Dissolution of minerals with rough surfaces

NASA Astrophysics Data System (ADS)

de Assis, Thiago A.; Aarão Reis, Fábio D. A.

2018-05-01

We study dissolution of minerals with initial rough surfaces using kinetic Monte Carlo simulations and a scaling approach. We consider a simple cubic lattice structure, a thermally activated rate of detachment of a molecule (site), and rough surface configurations produced by fractional Brownian motion algorithm. First we revisit the problem of dissolution of initial flat surfaces, in which the dissolution rate rF reaches an approximately constant value at short times and is controlled by detachment of step edge sites. For initial rough surfaces, the dissolution rate r at short times is much larger than rF ; after dissolution of some hundreds of molecular layers, r decreases by some orders of magnitude across several time decades. Meanwhile, the surface evolves through configurations of decreasing energy, beginning with dissolution of isolated sites, then formation of terraces with disordered boundaries, their growth, and final smoothing. A crossover time to a smooth configuration is defined when r = 1.5rF ; the surface retreat at the crossover is approximately 3 times the initial roughness and is temperature-independent, while the crossover time is proportional to the initial roughness and is controlled by step-edge site detachment. The initial dissolution process is described by the so-called rough rates, which are measured for fixed ratios between the surface retreat and the initial roughness. The temperature dependence of the rough rates indicates control by kink site detachment; in general, it suggests that rough rates are controlled by the weakest microscopic bonds during the nucleation and formation of the lowest energy configurations of the crystalline surface. Our results are related to recent laboratory studies which show enhanced dissolution in polished calcite surfaces. In the application to calcite dissolution in alkaline environment, the minimal values of recently measured dissolution rate spectra give rF ∼10-9 mol/(m2 s), and the calculated rate laws of our model give rough rates in the range 10-6 -10-5 mol/(m2 s). This estimate is consistent with the range of calcite dissolution rates obtained in a recent work after treatment of literature data, which suggests the universal control of kink site dissolution in short term laboratory works. The weak effects of lattice size on our results also suggest that smoothing of mineral grain surfaces across geological times may be a microscopic explanation for the difference of chemical weathering rate of silicate minerals in laboratory and in the environment.

Formation and Coloring Mechanism of Typical Aluminosilicate Clay Minerals for CoAl2O4 Hybrid Pigment Preparation

PubMed Central

Zhang, Anjie; Mu, Bin; Wang, Xiaowen; Wen, Lixin; Wang, Aiqin

2018-01-01

Different kinds of aluminosilicate minerals were employed to fabricate CoAl2O4 hybrid pigment for studying its formation and coloring mechanism. It revealed that the color of the obtained hybrid pigments was determined by the content of Al2O3 and lightness of clay minerals. The higher the Al2O3 content and the lightness of clay minerals, the better the color parameters of hybrid pigments. During the preparation of hybrid pigments, CoAl2O4 nanoparticles were confined to be loaded on the surface of the aluminosilicate minerals, which effectively prevented from the aggregation and the size increase of CoAl2O4 nanoparticles. What's more, aluminosilicate mineral might be an ideal natural aluminum source to compensate the aluminum loss due to the dissolution of Al(OH)3 at alkaline medium during precursor preparation, keeping an optimum molar ratio of Co2+/Al3+ for formation of spinel CoAl2O4 pigments in the process of high-temperature crystallization. PMID:29725589

Formation and Coloring Mechanism of Typical Aluminosilicate Clay Minerals for CoAl2O4 Hybrid Pigment Preparation.

PubMed

Zhang, Anjie; Mu, Bin; Wang, Xiaowen; Wen, Lixin; Wang, Aiqin

2018-01-01

Different kinds of aluminosilicate minerals were employed to fabricate CoAl 2 O 4 hybrid pigment for studying its formation and coloring mechanism. It revealed that the color of the obtained hybrid pigments was determined by the content of Al 2 O 3 and lightness of clay minerals. The higher the Al 2 O 3 content and the lightness of clay minerals, the better the color parameters of hybrid pigments. During the preparation of hybrid pigments, CoAl 2 O 4 nanoparticles were confined to be loaded on the surface of the aluminosilicate minerals, which effectively prevented from the aggregation and the size increase of CoAl 2 O 4 nanoparticles. What's more, aluminosilicate mineral might be an ideal natural aluminum source to compensate the aluminum loss due to the dissolution of Al(OH) 3 at alkaline medium during precursor preparation, keeping an optimum molar ratio of Co 2+ /Al 3+ for formation of spinel CoAl 2 O 4 pigments in the process of high-temperature crystallization.

Explosive eruption of coal and basalt and the end-Permian mass extinction

PubMed Central

Ogden, Darcy E.; Sleep, Norman H.

2012-01-01

The end-Permian extinction decimated up to 95% of carbonate shell-bearing marine species and 80% of land animals. Isotopic excursions, dissolution of shallow marine carbonates, and the demise of carbonate shell-bearing organisms suggest global warming and ocean acidification. The temporal association of the extinction with the Siberia flood basalts at approximately 250 Ma is well known, and recent evidence suggests these flood basalts may have mobilized carbon in thick deposits of organic-rich sediments. Large isotopic excursions recorded in this period are potentially explained by rapid venting of coal-derived methane, which has primarily been attributed to metamorphism of coal by basaltic intrusion. However, recently discovered contemporaneous deposits of fly ash in northern Canada suggest large-scale combustion of coal as an additional mechanism for rapid release of carbon. This massive coal combustion may have resulted from explosive interaction with basalt sills of the Siberian Traps. Here we present physical analysis of explosive eruption of coal and basalt, demonstrating that it is a viable mechanism for global extinction. We describe and constrain the physics of this process including necessary magnitudes of basaltic intrusion, mixing and mobilization of coal and basalt, ascent to the surface, explosive combustion, and the atmospheric rise necessary for global distribution. PMID:22184229

Leaching kinetics of As, Mo, and Se from acidic coal fly ash samples

DOE Office of Scientific and Technical Information (OSTI.GOV)

Neupane, Ghanashyam; Donahoe, Rona J.; Bhattacharyya, Siddhartha

Annually, coal-fired electric power plants produce large volumes potentially hazardous coal combustion products (CCPs) including fly ash. Since majority of the coal fly ash and other CCPs deposited in dry land fills or wet lagoons, they pose risk of contamination to local environment and hydrogeology. In this study, we present results of leaching kinetics for As, Mo, and Se from three acidic fly ash samples. This study shows that the leachate concentrations of As, Mo, and Se increase over time. Three kinetics equations, pseudo-second order, Elovich, and power-function, are able to adequately describe the experimental leaching kinetics data. Experimental leachingmore » data and modeling results indicate that the rate limiting leaching of As, Mo, and Se is largely controlled by the dissolution of the fly ash particles. Furthermore, it is important to adopt effective containment/treatment schemes to avoid potential and persistent dispersion of trace elements from ash disposal facilities to surrounding environment for a long time.« less

Leaching kinetics of As, Mo, and Se from acidic coal fly ash samples

DOE PAGES

Neupane, Ghanashyam; Donahoe, Rona J.; Bhattacharyya, Siddhartha; ...

2017-07-03

Annually, coal-fired electric power plants produce large volumes potentially hazardous coal combustion products (CCPs) including fly ash. Since majority of the coal fly ash and other CCPs deposited in dry land fills or wet lagoons, they pose risk of contamination to local environment and hydrogeology. In this study, we present results of leaching kinetics for As, Mo, and Se from three acidic fly ash samples. This study shows that the leachate concentrations of As, Mo, and Se increase over time. Three kinetics equations, pseudo-second order, Elovich, and power-function, are able to adequately describe the experimental leaching kinetics data. Experimental leachingmore » data and modeling results indicate that the rate limiting leaching of As, Mo, and Se is largely controlled by the dissolution of the fly ash particles. Furthermore, it is important to adopt effective containment/treatment schemes to avoid potential and persistent dispersion of trace elements from ash disposal facilities to surrounding environment for a long time.« less

Predictors of supportive coparenting after relationship dissolution among at-risk parents.

PubMed

Kamp Dush, Claire M; Kotila, Letitia E; Schoppe-Sullivan, Sarah J

2011-06-01

Supportive coparenting after relationship dissolution is associated with increased father involvement which can buffer against the negative effects of parental relationship dissolution. Low-income, at-risk families are much more likely to experience relationship dissolutions; hence, supportive coparenting after dissolution is particularly important in these families. We examined whether relationship (commitment and quality) and child (difficult temperament and gender) characteristics predicted initial levels of, and change in, supportive coparenting after relationship dissolution in the Fragile Families and Child Wellbeing Study (N = 1,603). We used structural equation modeling of latent growth curves to examine four time points collected at the focal child's birth and first, third, and fifth birthdays. Ninety-percent of the mothers had nonmarital births, and about three-quarters had a high school diploma or less education. Overall, supportive coparenting decreased over time. Mothers in more committed relationships prior to the dissolution initially had significantly lower supportive coparenting. But over time, mothers who had been in more committed relationships increased in supportive coparenting. Mothers who had been in higher quality relationships prior to dissolution initially reported more supportive coparenting. At each time point, if a mother was romantically involved with a new partner, she reported significantly lower supportive coparenting compared to mothers who were single. With regard to child characteristics, mothers who reported their child as more difficult had significantly lower initial supportive coparenting. Similar results for fathers are discussed. Overall, the relationship characteristics of parents were important predictors of supportive coparenting both initially and over time. 2011 APA, all rights reserved

Catalysts and process developments for two-stage liquefaction. Fourth quarterly technical progress report, July 1, 1991--September 30, 1991

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cronauer, D.C.; Swanson, A.J.; Sajkowski, D.J.

Research under way in this project centers upon developing and evaluating catalysts and process improvements for coal liquefaction in the two-stage close-coupled catalytic process. As documented in the previous quarterly report there was little advantage for presoaking Black Thunder coal or Martin Lake lignite in a hydrogen-donor solvent, such as tetralin, at temperatures up to 600{degrees}F prior to liquefaction at higher temperatures. The amount of decarboxylation that occurred during the presoaking of Black Thunder coal or Martin Lake lignite in tetralin in the temperature range of 400 to 600{degrees}F was also relatively small. As indicated by both CO{sub 2} releasemore » and the change in oxygen-containing coal functionality, the level of decarboxylation in coal-derived solvent seems to correlate with the depth of coal dissolution. The feedstock liquefaction studies for the three feedstocks (Black Thunder subbituminous coal, Martin Lake lignite, and Illinois No. 6 coal) have been completed, and their results were compared in this report. Both Black Thunder coal and Martin Lake lignite gave lighter products than Illinois No. 6 coal at similar process conditions. Severe catalyst deactivation in the first stage was also observed with the Martin Lake lignite run. The first stage catalyst testing program was started. After a successful reference run with Illinois No. 6 coal, a high temperature run with AMOCAT{trademark} 1C was completed. In addition, a run was made with Illinois No. 6 coal using an oil-soluble catalyst, Molyvan L, in the first stage and AMOCAT{trademark} 1C in the second stage, where preliminary run results look promising.« less

TEM study of PM2.5 emitted from coal and tire combustion in a thermal power station.

PubMed

Gieré, Reto; Blackford, Mark; Smith, Katherine

2006-10-15

The research presented here was conducted within the scope of an experiment investigating technical feasibility and environmental impacts of tire combustion in a coal-fired power station. Previous work has shown that combustion of a coal+tire blend rather than pure coal increased bulk emissions of various elements (e.g., Zn, As, Sb, Pb). The aim of this study is to characterize the chemical and structural properties of emitted single particles with dimensions <2.5 microm (PM2.5). This transmission electron microscope (TEM)-based study revealed that, in addition to phases typical of coal fly ash (e.g., aluminum-silicate glass, mullite), the emitted PM2.5 contains amorphous selenium particles and three types of crystalline metal sulfates never reported before from stack emissions. Anglesite, PbSO4, is ubiquitous in the PM2.5 derived from both fuels and contains nearly all Pb present in the PM. Gunningite, ZnSO4-H2O, is the main host for Zn and only occurs in the PM derived from the coal+tire blend, whereas yavapaiite, KFe3+(SO4)2, is present only when pure coal was combusted. We conclude that these metal sulfates precipitated from the flue gas, may be globally abundant aerosols, and have, through hydration or dissolution, a major environmental and health impact.

Fate of the naturally occurring radioactive materials during treatment of acid mine drainage with coal fly ash and aluminium hydroxide.

PubMed

Madzivire, Godfrey; Maleka, Peane P; Vadapalli, Viswanath R K; Gitari, Wilson M; Lindsay, Robert; Petrik, Leslie F

2014-01-15

Mining of coal is very extensive and coal is mainly used to produce electricity. Coal power stations generate huge amounts of coal fly ash of which a small amount is used in the construction industry. Mining exposes pyrite containing rocks to H2O and O2. This results in the oxidation of FeS2 to form H2SO4. The acidic water, often termed acid mine drainage (AMD), causes dissolution of potentially toxic elements such as, Fe, Al, Mn and naturally occurring radioactive materials such as U and Th from the associated bedrock. This results in an outflow of AMD with high concentrations of sulphate ions, Fe, Al, Mn and naturally occurring radioactive materials. Treatment of AMD with coal fly ash has shown that good quality water can be produced which is suitable for irrigation purposes. Most of the potentially toxic elements (Fe, Al, Mn, etc) and substantial amounts of sulphate ions are removed during treatment with coal fly ash. This research endeavours to establish the fate of the radioactive materials in mine water with coal fly ash containing radioactive materials. It was established that coal fly ash treatment method was capable of removing radioactive materials from mine water to within the target water quality range for drinking water standards. The alpha and beta radioactivity of the mine water was reduced by 88% and 75% respectively. The reduced radioactivity in the mine water was due to greater than 90% removal of U and Th radioactive materials from the mine water after treatment with coal fly ash as ThO2 and UO2. No radioisotopes were found to leach from the coal fly ash into the mine water. Copyright © 2013 Elsevier Ltd. All rights reserved.

Sulfate formation catalyzed by coal fly ash, mineral dust and iron(iii) oxide: variable influence of temperature and light.

PubMed

Gankanda, Aruni; Coddens, Ellen M; Zhang, Yaping; Cwiertny, David M; Grassian, Vicki H

2016-12-08

Recent atmospheric field and modeling studies have highlighted a lack of understanding of the processes responsible for high levels of sulfate aerosol in the atmosphere, ultimately arising from a dearth of experimental data on such processes. Here we investigated the effect of temperature and simulated solar radiation on the catalytic oxidation of S(iv) to S(vi) (i.e., sulfite to sulfate) in aqueous suspensions of several metal-containing, atmospherically relevant particles including coal fly ash (FA), Arizona test dust (ATD) and an iron oxide (γ-Fe 2 O 3 ). The effect of temperature and light on S(iv) oxidation was found to be very different for these three samples. For example, in the presence of FA and γ-Fe 2 O 3 the temporal evolution of dissolved Fe(ii) (formed via reductive particle dissolution) correlated with S(iv) oxidation. Accordingly, we propose that S(iv) oxidation in most of these systems initially occurs primarily at the particle surface (i.e., a heterogeneous reaction pathway), although a solution-phase (i.e., homogeneous) catalytic pathway also contributes over later timescales due to the formation and accumulation of dissolved Fe(iii) (generated via oxidation of dissolved Fe(ii) by O 2 ). It is likely that the homogeneous reaction pathway is operative at initial times in the presence of γ-Fe 2 O 3 at 25 °C. In contrast, S(iv) oxidation in the presence of ATD appears to proceed entirely via a heterogeneous reaction, which notably does not lead to any iron dissolution. In fact, the greater overall rate of S(iv) loss in the presence of ATD compared to FA and γ-Fe 2 O 3 suggests that other factors, including greater adsorption of sulfite, transition metal ion (TMI) catalysis by other metal ions (e.g., Ti), or different species of iron in ATD, play a role. Overall these studies suggest that the rate, extent and products of atmospheric S(iv) oxidation can be highly variable and dependent upon the nature of aerosol sources and ambient conditions (e.g., temperature and irradiance). Ultimately, such complexity precludes simple, broadly generalized schemes for this reaction when modeling atmospheric processes involving diverse components of different mineral dust aerosol as well as other metal-containing aerosol.

25 CFR 11.606 - Dissolution proceedings.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 25 Indians 1 2012-04-01 2011-04-01 true Dissolution proceedings. 11.606 Section 11.606 Indians... ORDER CODE Domestic Relations § 11.606 Dissolution proceedings. (a) Either or both parties to the marriage may initiate dissolution proceedings. (b) If a proceeding is commenced by one of the parties, the...

25 CFR 11.606 - Dissolution proceedings.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 25 Indians 1 2013-04-01 2013-04-01 false Dissolution proceedings. 11.606 Section 11.606 Indians... ORDER CODE Domestic Relations § 11.606 Dissolution proceedings. (a) Either or both parties to the marriage may initiate dissolution proceedings. (b) If a proceeding is commenced by one of the parties, the...

25 CFR 11.606 - Dissolution proceedings.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 25 Indians 1 2011-04-01 2011-04-01 false Dissolution proceedings. 11.606 Section 11.606 Indians... ORDER CODE Domestic Relations § 11.606 Dissolution proceedings. (a) Either or both parties to the marriage may initiate dissolution proceedings. (b) If a proceeding is commenced by one of the parties, the...

25 CFR 11.606 - Dissolution proceedings.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 25 Indians 1 2014-04-01 2014-04-01 false Dissolution proceedings. 11.606 Section 11.606 Indians... ORDER CODE Domestic Relations § 11.606 Dissolution proceedings. (a) Either or both parties to the marriage may initiate dissolution proceedings. (b) If a proceeding is commenced by one of the parties, the...

Anaerobic microbial dissolution of lead and production of organic acids

DOEpatents

Francis, Arokiasamy J.; Dodge, Cleveland; Chendrayan, Krishnachetty; Quinby, Helen L.

1988-01-01

The present invention relates to an anaerobic bacterial culture of Clostridium sp. ATCC No. 53464 which solubilizes lead oxide under anaerobic conditions in coal and industrial wastes and therefore presents a method of removing lead from such wastes before they are dumped into the environment. The rate of lead dissolution during logarithmic growth of the bacteria in 40 ml medium containing 3.32 .mu.moles of lead as lead oxide was 0.042 .mu.moles ml.sup.-1 hr.sup.-1. Dissolution of lead oxide by the bacterial isolate is due to the production of metabolites and acidity in the culture medium. The major metabolites are acetic, butyric and lactic acid. Clostridium sp. ATCC No. 53464 can be used in the recovery of strategic metals from ores and wastes and also for the production of lactic acid for commercial purposes. The process yields large quantities of lactic acid as well as lead complexed in a stable form with said acids.

Hydrobiogeochemical interactions in 'anoxic' limestone drains for neutralization of acidic mine drainage

USGS Publications Warehouse

Robbins, E.I.; Cravotta, C.A.; Savela, C.E.; Nord, G.L.

1999-01-01

Processes affecting neutralization of acidic coal mine drainage were evaluated within 'anoxic' limestone drains (ALDs). Influents had pH???3.5 and dissolved oxygen <2 mg/l. Even though effluents were near neutral (pH 6 and alkalinity acidity), two of the four ALDs were failing due to clogging. Mineral-saturation indices indicated the potential for dissolution of calcite and gypsum, and precipitation of Al3+ and Fe3+ compounds. Cleavage mounts of calcite and gypsum that were suspended within the ALDs and later examined microscopically showed dissolution features despite coatings by numerous bacteria, biofilms, and Fe-Al-Si precipitates. In the drain exhibiting the greatest flow reduction, Al-hydroxysulfates had accumulated on limestone surfaces and calcite etch points, thus causing the decline in transmissivity and dissolution. Therefore, where Al loadings are high and flow rates are low, a pre-treatment step is indicated to promote Al removal before diverting acidic mine water into alkalinity-producing materials. ?? 1998 Elsevier Science Ltd.

Effects of selective handling of pyritic, acid-forming materials on the chemistry of pore gas and ground water at a reclaimed surface coal mine in Clarion County, PA, USA

USGS Publications Warehouse

Cravotta,, Charles A.; Dugas, Diana L.; Brady, Keith; Kovalchuck, Thomas E.

1994-01-01

A change from dragline to “selective handling” mining methods at a reclaimed surface coal mine in western Pennsylvania did not significantly affect concentrations of metals in ground water because oxidation of pyrite and dissolution of siderite were not abated. Throughout the mine, placement of pyritic material near the land surface facilitated the oxidation of pyrite, causing the consumption of oxygen (O2) and release of acid, iron, and sulfate ions. Locally in the unsaturated zone, water sampled within or near pyritic zones was acidic, with concentrations of sulfate exceeding 3,000 milligrams per liter (mg/L). However, acidic conditions generally did not persist below the water table because of neutralization by carbonate minerals. Dissolution of calcite, dolomite, and siderite in unsaturated and saturated zones produced elevated concentrations of carbon dioxide (CO2), alkalinity, calcium, magnesium, iron, and manganese. Alkalinity concentrations of 600 to 800 mg/L as CaCO3 were common in water samples from the unsaturated zone in spoil, and alkalinities of 100 to 400 mg/L as CaCO3 were common in ground-water samples from the underlying saturated zone in spoil and bedrock. Saturation indices indicated that siderite could dissolve in water throughout the spoil, but that calcite dissolution or precipitation could occur locally. Calcite dissolution could be promoted as a result of pyrite oxidation, gypsum precipitation, and calcium ion exchange for sodium. Calcite precipitation could be promoted by evapotranspiration and siderite dissolution, and corresponding increases in concentrations of alkalinity and other solutes. Partial pressures of O2 (Po2) and CO2 (Pco2) in spoil pore gas indicated that oxidation of pyrite and precipitation of ferric hydroxide, coupled with dissolution of calcite, dolomite, and siderite were the primary reactions affecting water quality. Highest vertical gradients in Po2, particularly in the near-surface zone (0-1 m), did not correlate with concentrations of total sulfur in spoil. This lack of correlation could indicate that total sulfur concentrations in spoil do not reflect the amount of reactive pyrite or that oxidation rates can be controlled more by rates of O2 diffusion than the amount of pyrite. Hence, if placed in O2-rich zones near the land surface, even small amounts of disseminated pyritic material can be relatively significant sources of acid and mineralized water.

Evaluation of correlation between dissolution rates of loxoprofen tablets and their surface morphology observed by scanning electron microscope and atomic force microscope.

PubMed

Yoshikawa, Shinichi; Murata, Ryo; Shida, Shigenari; Uwai, Koji; Suzuki, Tsuneyoshi; Katsumata, Shunji; Takeshita, Mitsuhiro

2010-01-01

We observed the surface morphological structures of 60 mg tablets of Loxonin, Loxot, and Lobu using scanning electron microscope (SEM) and atomic force microscope (AFM) to evaluate the dissolution rates. We found a significant difference among the initial dissolution rates of the three kinds of loxoprofen sodium tablets. Petal forms of different sizes were commonly observed on the surface of the Loxonin and Loxot tablets in which loxoprofen sodium was confirmed by measuring the energy-dispersible X-ray (EDX) spectrum of NaKalpha using SEM. However, a petal form was not observed on the surface of the Lobu tablet, indicating differences among the drug production processes. Surface area and particle size of the principal ingredient in tablets are important factors for dissolution rate. The mean size of the smallest fine particles constituting each tablet was also determined with AFM. There was a correlation between the initial dissolution rate and the mean size of the smallest particles in each tablet. Visualizing tablet surface morphology using SEM and AFM provides information on the drug production processes and initial dissolution rate, and is associated with the time course of pharmacological activities after tablet administration.

Olivine dissolution from Indian dunite in saline water.

PubMed

Agrawal, Amit Kumar; Mehra, Anurag

2016-11-01

The rate and mechanism of olivine dissolution was studied using naturally weathered dunite FO 98.21 (Mg 1.884 Fe 0.391 SiO 4 ) from an Indian source, that also contains serpentine mineral lizardite. A series of batch dissolution experiments were carried out to check the influence of temperature (30-75 ∘ C), initial dunite concentration (0.5 and 20 g/L), and salinity (0-35 g/L NaCl) under fixed head space CO 2 pressure (P[Formula: see text] = 1 barg) on dunite dissolution. Dissolved Mg, Si, and Fe concentrations were determined by inductive coupled plasma atomic emission spectroscopy. End-product solids were characterized by scanning electron microscopy and X-ray diffraction. Initially, rates of dissolution of Si and Mg were observed to be in stoichiometric proportion. After 8 h, the dissolution rate was observed to decline. At the end of the experiment (504 h), an amorphous silica-rich layer was observed over the dunite surface. This results in decay of the dissolution rate. The operating conditions (i.e., salinity, temperature, and mineral loading) affect the dissolution kinetics in a very complex manner because of which the observed experimental trends do not exhibit a direct trend.

Natural radionuclides in plants, soils and sediments affected by U-rich coal mining activities in Brazil.

PubMed

Galhardi, Juliana Aparecida; García-Tenorio, Rafael; Bonotto, Daniel Marcos; Díaz Francés, Inmaculada; Motta, João Gabriel

2017-10-01

Mining activities can increase the mobility of metals by accelerating the dissolution and leaching of minerals from the rocks and tailing piles to the environment and, consequently, their availability for plants and subsequent transfer to the food chain. The weathering of minerals and the disposal of coal waste in tailing piles can accelerate the generation of acid mine drainage (AMD), which is responsible for the higher dissolution of metals in mining areas. In this context, the behavior of U, Th and K in soils and sediment, and the transfer factor (TF) of 238 U, 234 U and 210 Po for soybean, wheat, pine and eucalyptus cultivated around a coal mine in southern Brazil was evaluated. Alpha and gamma spectrometry were used for the measurements of the activity concentration of the radioelements. 210 Po was the radionuclide that is most accumulated in the plants, especially in the leaves. When comparing the plant species, pine showed the highest TF values for 234 U (0.311 ± 0.420) for leaves, while eucalyptus showed the highest TF for 238 U (0.344 ± 0.414) for leaves. In general, TF were higher for the leaves of soybean and wheat when compared to the grains, and grains of wheat showed higher TF for 210 Po and 238 U than grains of soybean. Deviations from the natural U isotopic ratio were recorded at all investigated areas, indicating possible industrial and mining sources of U for the vegetables. A safety assessment of transport routes and accumulation of radionuclides in soils with a potential for cultivation is important, mainly in tropical areas contaminated with solid waste and effluents from mines and industry. Copyright © 2017 Elsevier Ltd. All rights reserved.

Environmental characterisation of coal mine waste rock in the field: an example from New Zealand

NASA Astrophysics Data System (ADS)

Hughes, J.; Craw, D.; Peake, B.; Lindsay, P.; Weber, P.

2007-08-01

Characterisation of mine waste rock with respect to acid generation potential is a necessary part of routine mine operations, so that environmentally benign waste rock stacks can be constructed for permanent storage. Standard static characterisation techniques, such as acid neutralisation capacity (ANC), maximum potential acidity, and associated acid-base accounting, require laboratory tests that can be difficult to obtain rapidly at remote mine sites. We show that a combination of paste pH and a simple portable carbonate dissolution test, both techniques that can be done in the field in a 15 min time-frame, is useful for distinguishing rocks that are potentially acid-forming from those that are acid-neutralising. Use of these techniques could allow characterisation of mine wastes at the metre scale during mine excavation operations. Our application of these techniques to pyrite-bearing (total S = 1-4 wt%) but variably calcareous coal mine overburden shows that there is a strong correlation between the portable carbonate dissolution technique and laboratory-determined ANC measurements (range of 0-10 wt% calcite equivalent). Paste pH measurements on the same rocks are bimodal, with high-sulphur, low-calcite rocks yielding pH near 3 after 10 min, whereas high-ANC rocks yield paste pH of 7-8. In our coal mine example, the field tests were most effective when used in conjunction with stratigraphy. However, the same field tests have potential for routine use in any mine in which distinction of acid-generating rocks from acid-neutralising rocks is required. Calibration of field-based acid-base accounting characteristics of the rocks with laboratory-based static and/or kinetic tests is still necessary.

Arsenic-bearing pyrite and marcasite in the Fire Clay coal bed, Middle Pennsylvanian Breathitt Formation, eastern Kentucky

USGS Publications Warehouse

Ruppert, L.F.; Hower, J.C.; Eble, C.F.

2005-01-01

Arsenic concentrations determined on 11 lithotype samples from the Middle Pennsylvanian Breathitt Group Fire Clay coal bed, Leslie County, KY, range from 1 to 418 ppm (whole coal basis). The 11 lithotype samples, which vary in thickness from 4 to 18 cm, were sampled from a continuous 1.38 m channel sample, and were selected based on megascopic appearance (vitrain-rich versus attrital-rich). A lithotype that contains 418 ppm As is located near the top of the coal bed and is composed of 10.5 cm of bright clarain bands containing fusain that, within short distances, grade laterally into Fe sulfide bands. To determine the mode of occurrence of As in this lithotype, the coal was examined with scanning electron microscopy and analyzed by energy dispersive X-ray fluorescence. Massive, framboidal, cell filling, cell-wall replacement, and radiating forms of Fe sulfide were observed in the high As lithotype; many of the radiating Fe sulfide forms, and one of the cell-wall replacements contained As. Examination of the grains with optical light microscopy shows that the majority of radiating morphologies are pyrite, the remainder are marcasite. Selected Fe sulfide grains were also analyzed by electron microprobe microscopy. Arsenic concentrations within individual grains range from 0.0 wt.% to approximately 3.5 wt.%. On the basis of morphology, these Fe sulfides are presumed to be of syngenetic origin and would probably be removed from the coal during physical coal cleaning, thus eliminating a potential source of As from the coal combustion process. However, because the grains are radiating and have high surface area, dissolution and release of As could occur if the pyrite is oxidized in refuse ponds.

Clean coal initiatives in Indiana

USGS Publications Warehouse

Bowen, B.H.; Irwin, M.W.; Sparrow, F.T.; Mastalerz, Maria; Yu, Z.; Kramer, R.A.

2007-01-01

Purpose - Indiana is listed among the top ten coal states in the USA and annually mines about 35 million short tons (million tons) of coal from the vast reserves of the US Midwest Illinois Coal Basin. The implementation and commercialization of clean coal technologies is important to the economy of the state and has a significant role in the state's energy plan for increasing the use of the state's natural resources. Coal is a substantial Indiana energy resource and also has stable and relatively low costs, compared with the increasing costs of other major fuels. This indigenous energy source enables the promotion of energy independence. The purpose of this paper is to outline the significance of clean coal projects for achieving this objective. Design/methodology/approach - The paper outlines the clean coal initiatives being taken in Indiana and the research carried out at the Indiana Center for Coal Technology Research. Findings - Clean coal power generation and coal for transportation fuels (coal-to-liquids - CTL) are two major topics being investigated in Indiana. Coking coal, data compilation of the bituminous coal qualities within the Indiana coal beds, reducing dependence on coal imports, and provision of an emissions free environment are important topics to state legislators. Originality/value - Lessons learnt from these projects will be of value to other states and countries.

Anaerobic microbial dissolution of lead and production of organic acids

DOEpatents

Francis, A.J.; Dodge, C.; Chendrayan, K.; Quinby, H.L.

1987-04-16

The present invention related to an anaerobic bacterial culture of Clostridium sp. ATCC No. 53464 which solubilizes lead oxide under anaerobic conditions in coal and industrial wastes and therefore presents a method of removing lead from such wastes before they are dumped into the environment. The rat of lead dissolution during logarithmic growth of the bacteria in 40 ml medium containing 3.32 ..mu..moles of lead as lead oxide was 0.042 ..mu..moles m1/sup /-/1/ hr/sup /-/1/. Dissolution of lead oxide by the bacterial isolate is due to the production of metabolites and acidity in the culture medium. The major metabolites are acetic, butyric and lactic acid. The major metabolites are acetic, butyric and lactic acid. Clostridium sp. ATCC No. 53464 can be used in the recovery of the strategic metals from ores and wastes and also for the production of lactic acid for commercial purposes. The process yields large quantities of lactic acid as well as lead complexed in a stable form with said acids. 4 figs., 3 tabs.

Geochemical characteristics of dissolved rare earth elements in acid mine drainage from abandoned high-As coal mining area, southwestern China.

PubMed

Li, Xuexian; Wu, Pan

2017-09-01

Acid mine drainage (AMD) represents a major source of water pollution in the small watershed of Xingren coalfield in southwestern Guizhou Province. A detailed geochemical study was performed to investigate the origin, distribution, and migration of REEs by determining the concentrations of REEs and major solutes in AMD samples, concentrations of REEs in coal, bedrocks, and sediment samples, and modeling REEs aqueous species. The results highlighted that all water samples collected in the mining area are identified as low pH, high concentrations of Fe, Al, SO 4 2- and distinctive As and REEs. The spatial distributions of REEs showed a peak in where it is nearby the location of discharging of AMD, and then decrease significantly with distance away from the mining areas. Lots of labile REEs have an origin of coal and bedrocks, whereas the acid produced by the oxidation of pyrite is a prerequisite to cause the dissolution of coal and bedrocks, and then promoting REEs release in AMD. The North American Shale Composite (NASC)-normalized REE patterns of coal and bedrocks are enriched in light REEs (LREEs) and middle REEs (MREEs) relative to heavy REEs (HREEs). Contrary to these solid samples, AMD samples showed slightly enrichment of MREEs compared with LREEs and HREEs. This behavior implied that REEs probably fractionate during acid leaching, dissolution of bedrocks, and subsequent transport, so that the MREEs is primarily enriched in AMD samples. Calculation of REEs inorganic species for AMD demonstrated that sulfate complexes (Ln(SO 4 ) + and Ln(SO 4 ) 2 - ) predominate in these species, accounting for most of proportions for the total REEs species. The high concentrations of dissolved SO 4 2- and low pH play a decisive role in controlling the presence of REEs in AMD, as these conditions are necessary for formation of stable REEs-sulfate complexes in current study. The migration and transportation of REEs in AMD are more likely constrained by adsorption and co-precipitation of Fe-Al hydroxides/hydroxysulfate. In addition, the MREEs is preferentially captured by poorly crystalline Fe-Al hydroxides/hydroxysulfate, which favors that sediments also preserve NASC-normalized patterns with MREEs enrichment in the stream.

25 CFR 11.606 - Dissolution proceedings.

Code of Federal Regulations, 2010 CFR

2010-04-01

... marriage may initiate dissolution proceedings. (b) If a proceeding is commenced by one of the parties, the... proceeding for dissolution of marriage or legal separation shall allege that the marriage is irretrievably... under the jurisdiction of the court of each party; (2) The date of the marriage and the place at which...

Dissolution of Uranium Oxides Under Alkaline Oxidizing Conditions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smith, Steven C.; Peper, Shane M.; Douglas, Matthew

2009-11-01

Bench scale experiments were conducted to determine the dissolution characteristics of uranium oxide powders (UO2, U3O8, and UO3) in aqueous peroxide-carbonate solutions. Experimental parameters included H2O2 concentration, carbonate counter cation (NH4+, Na+, K+, and Rb+), and pH. Results indicate the dissolution rate of UO2 in 1 M (NH4)2CO3 increases linearly with peroxide concentration ranging from 0.05 – 2 M. The three uranium oxide powders exhibited different dissolution patterns however, UO3 exhibited prompt complete dissolution. Carbonate counter cation affected the dissolution kinetics. There is minimal impact of solution pH, over the range 8.8 to 10.6, on initial dissolution rate.

Quantification of the resist dissolution process: an in situ analysis using high speed atomic force microscopy

NASA Astrophysics Data System (ADS)

Santillan, Julius Joseph; Shichiri, Motoharu; Itani, Toshiro

2016-03-01

This work focuses on the application of a high speed atomic force microscope (HS-AFM) for the in situ visualization / quantification of the resist dissolution process. This technique, as reported in the past, has provided useful pointers on the formation of resist patterns during dissolution. This paper discusses about an investigation made on the quantification of what we refer to as "dissolution unit size" or the basic units of patterning material dissolution. This was done through the establishment of an originally developed analysis method which extracts the difference between two succeeding temporal states of the material film surface (images) to indicate the amount of change occurring in the material film at a specific span of time. Preliminary experiments with actual patterning materials were done using a positive-tone EUV model resist composed only of polyhydroxystyrene (PHS)-based polymer with a molecular weight of 2,500 and a polydispersity index of 1.2. In the absence of a protecting group, the material was utilized at a 50nm film thickness with post application bake of 90°C/60s. The resulting film is soluble in the alkali-based developer even without exposure. Results have shown that the dissolution components (dissolution unit size) of the PHS-based material are not of fixed size. Instead, it was found that aside from one constantly dissolving unit size, another, much larger dissolution unit size trend also occurs during material dissolution. The presence of this larger dissolution unit size suggests an occurrence of "polymer clustering". Such polymer clustering was not significantly present during the initial stages of dissolution (near the original film surface) but becomes more persistently obvious after the dissolution process reaches a certain film thickness below the initial surface.

Biochemical bond breaking in coal: Third quarterly report, (April through June 1987)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1987-07-01

Major research efforts are presently being conducted in three principal areas of focus: (1) optimization of coal biosolubilization; (2) characterization of the solubilized products resulting from microbial coal depolymerization; and (3) degradation of model compounds to assess potential interunit linkages which may be attacked by whole culture or cell-free culture supernatants containing extracellular enzymes. Initial evaluations of the various combinations of microbes, coals, and coal pretreatments indicated that CP1 and CP1 + 2 solubilized all of the coals selected for this project at substantially higher rates than S. setonii or T. versicolor. The ARC CP1 + 2 consortium was chosenmore » as the primary culture for detailed evaluation of coal biosolubilization and model compound degradation. Studies were conducted to determine if solubilization of coal by CP1 + 2 supernatants could be enhanced by elevating the temperature. Solubilization of both untreated Leonardite and HNO3 treated Wyodak (Smith-Roland) subbituminous coal was increased when elevating the temperature from ambient to 35C. The initial solubilization rate (T0 - 1 hour) of Leonardite at 22C was 16 OD units/hour and at 35C was 18 OD units/hour. Thus, an elevation of 13C enhanced solubilization of this coal by 12.5%. The effect of temperature on solubilization of Wyodak coal appeared to be more pronounced. Solubilization of HNO3 treated coals by the CP organisms is not only relatively rapid, but is also extensive. The relatively rapid and extensive coal solubilization attainable by CP1 + 2 has enabled us to produce quantities of product sufficient for analytical methods development and for characterization of the coal products. Initial attempts have been made to characterize the depolymerized products using HPLC and GC/MS. 9 figs., 3 tabs.« less

Chemical analyses of coal, coal-associated rocks and coal combustion products collected for the National Coal Quality Inventory

USGS Publications Warehouse

Hatch, Joseph R.; Bullock, John H.; Finkelman, Robert B.

2006-01-01

In 1999, the USGS initiated the National Coal Quality Inventory (NaCQI) project to address a need for quality information on coals that will be mined during the next 20-30 years. At the time this project was initiated, the publicly available USGS coal quality data was based on samples primarily collected and analyzed between 1973 and 1985. The primary objective of NaCQI was to create a database containing comprehensive, accurate and accessible chemical information on the quality of mined and prepared United States coals and their combustion byproducts. This objective was to be accomplished through maintaining the existing publicly available coal quality database, expanding the database through the acquisition of new samples from priority areas, and analysis of the samples using updated coal analytical chemistry procedures. Priorities for sampling include those areas where future sources of compliance coal are federally owned. This project was a cooperative effort between the U.S. Geological Survey (USGS), State geological surveys, universities, coal burning utilities, and the coal mining industry. Funding support came from the Electric Power Research Institute (EPRI) and the U.S. Department of Energy (DOE).

Strontium isotope quantification of siderite, brine and acid mine drainage contributions to abandoned gas well discharges in the Appalachian Plateau

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chapman, Elizabeth C.; Capo, Rosemary C.; Stewart, Brian W.

2013-04-01

Unplugged abandoned oil and gas wells in the Appalachian region can serve as conduits for the movement of waters impacted by fossil fuel extraction. Strontium isotope and geochemical analysis indicate that artesian discharges of water with high total dissolved solids (TDS) from a series of gas wells in western Pennsylvania result from the infiltration of acidic, low Fe (Fe < 10 mg/L) coal mine drainage (AMD) into shallow, siderite (iron carbonate)-cemented sandstone aquifers. The acidity from the AMD promotes dissolution of the carbonate, and metal- and sulfate-contaminated waters rise to the surface through compromised abandoned gas well casings. Strontium isotopemore » mixing models suggest that neither upward migration of oil and gas brines from Devonian reservoirs associated with the wells nor dissolution of abundant nodular siderite present in the mine spoil through which recharge water percolates contribute significantly to the artesian gas well discharges. Natural Sr isotope composition can be a sensitive tool in the characterization of complex groundwater interactions and can be used to distinguish between inputs from deep and shallow contamination sources, as well as between groundwater and mineralogically similar but stratigraphically distinct rock units. This is of particular relevance to regions such as the Appalachian Basin, where a legacy of coal, oil and gas exploration is coupled with ongoing and future natural gas drilling into deep reservoirs.« less

Illinois basin coal fly ashes. 2. Equilibria relationships and qualitative modeling of ash-water reactions

USGS Publications Warehouse

Roy, W.R.; Griffin, R.A.

1984-01-01

Alkaline and acidic Illinois Basin coal fly ash samples were each mixed with deionized water and equilibrated for about 140 days to simulate ash ponding environments. Common to both equilibrated solutions, anhydrite solubility dominated Ca2+ activities, and Al3+ activities were in equilibrium with both matrix mullite and insoluble aluminum hydroxide phases. Aqueous silica activities were controlled by both mullite and matrix silicates. The pH of the extract of the acidic fly ash was 4.1 after 24 h but increased to a pH value of 6.4 as the H2SO4, assumed to be adsorbed to the particle surfaces, was exhausted by the dissolution of matrix iron oxides and aluminosilicates. The activities of aqueous Al3+ and iron, initially at high levels during the early stages of equilibration, decreased to below analytical detection limits as the result of the formation of insoluble Fe and Al hydroxide phases. The pH of the extract of the alkaline fly ash remained above a pH value of 10 during the entire equilibration interval as a result of the hydrolysis of matrix oxides. As with the acidic system, Al3+ activities were controlled by amorphous aluminum hydroxide phases that began to form after about 7 days of equilibration. The proposed mechanisms and their interrelations are discussed in addition to the solubility diagrams used to deduce these relationships. ?? 1984 American Chemical Society.

Hydrochemical characterization and pollution sources identification of groundwater in Salawusu aquifer system of Ordos Basin, China.

PubMed

Yang, Qingchun; Wang, Luchen; Ma, Hongyun; Yu, Kun; Martín, Jordi Delgado

2016-09-01

Ordos Basin is located in an arid and semi-arid region of northwestern China, which is the most important energy source bases in China. Salawusu Formation (Q3 s) is one of the most important aquifer systems of Ordos Basin, which is adjacent to Jurassic coalfield areas. A large-scale exploitation of Jurassic coal resources over ten years results in series of influences to the coal minerals, such as exposed to the oxidation process and dissolution into the groundwater due to the precipitation infiltration. Therefore, how these processes impact groundwater quality is of great concerns. In this paper, the descriptive statistical method, Piper trilinear diagram, ratios of major ions and canonical correspondence analysis are employed to investigate the hydrochemical evolution, determine the possible sources of pollution processes, and assess the controls on groundwater compositions using the monitored data in 2004 and 2014 (before and after large-scale coal mining). Results showed that long-term exploration of coal resources do not result in serious groundwater pollution. The hydrochemical types changed from HCO3(-)-CO3(2-) facies to SO4(2-)-Cl facies during 10 years. Groundwater hardness, nitrate and sulfate pollution were identified in 2014, which was most likely caused by agricultural activities. Copyright © 2016 Elsevier Ltd. All rights reserved.

The Effect of a Tectonic Stress Field on Coal and Gas Outbursts

PubMed Central

An, Fenghua; Cheng, Yuanping

2014-01-01

Coal and gas outbursts have always been a serious threat to the safe and efficient mining of coal resources. Ground stress (especially the tectonic stress) has a notable effect on the occurrence and distribution of outbursts in the field practice. A numerical model considering the effect of coal gas was established to analyze the outburst danger from the perspective of stress conditions. To evaluate the outburst tendency, the potential energy of yielded coal mass accumulated during an outburst initiation was studied. The results showed that the gas pressure and the strength reduction from the adsorbed gas aggravated the coal mass failure and the ground stress altered by tectonics would affect the plastic zone distribution. To demonstrate the outburst tendency, the ratio of potential energy for the outburst initiation and the energy consumption was used. Increase of coal gas and tectonic stress could enhance the potential energy accumulation ratio, meaning larger outburst tendency. The component of potential energy for outburst initiation indicated that the proportion of elastic energy was increased due to tectonic stress. The elastic energy increase is deduced as the cause for a greater outburst danger in a tectonic area from the perspective of stress conditions. PMID:24991648

30 CFR 716.4 - Special bituminous coal mines.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 30 Mineral Resources 3 2011-07-01 2011-07-01 false Special bituminous coal mines. 716.4 Section... INTERIOR INITIAL PROGRAM REGULATIONS SPECIAL PERFORMANCE STANDARDS § 716.4 Special bituminous coal mines. (a) Definition. Special bituminous coal surface mines as used in this section means those bituminous...

30 CFR 716.4 - Special bituminous coal mines.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 30 Mineral Resources 3 2014-07-01 2014-07-01 false Special bituminous coal mines. 716.4 Section... INTERIOR INITIAL PROGRAM REGULATIONS SPECIAL PERFORMANCE STANDARDS § 716.4 Special bituminous coal mines. (a) Definition. Special bituminous coal surface mines as used in this section means those bituminous...

30 CFR 716.4 - Special bituminous coal mines.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 30 Mineral Resources 3 2012-07-01 2012-07-01 false Special bituminous coal mines. 716.4 Section... INTERIOR INITIAL PROGRAM REGULATIONS SPECIAL PERFORMANCE STANDARDS § 716.4 Special bituminous coal mines. (a) Definition. Special bituminous coal surface mines as used in this section means those bituminous...

30 CFR 716.4 - Special bituminous coal mines.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 30 Mineral Resources 3 2013-07-01 2013-07-01 false Special bituminous coal mines. 716.4 Section... INTERIOR INITIAL PROGRAM REGULATIONS SPECIAL PERFORMANCE STANDARDS § 716.4 Special bituminous coal mines. (a) Definition. Special bituminous coal surface mines as used in this section means those bituminous...

30 CFR 716.4 - Special bituminous coal mines.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 3 2010-07-01 2010-07-01 false Special bituminous coal mines. 716.4 Section... INTERIOR INITIAL PROGRAM REGULATIONS SPECIAL PERFORMANCE STANDARDS § 716.4 Special bituminous coal mines. (a) Definition. Special bituminous coal surface mines as used in this section means those bituminous...

Simulating star clusters with the AMUSE software framework. I. Dependence of cluster lifetimes on model assumptions and cluster dissolution modes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Whitehead, Alfred J.; McMillan, Stephen L. W.; Vesperini, Enrico

2013-12-01

We perform a series of simulations of evolving star clusters using the Astrophysical Multipurpose Software Environment (AMUSE), a new community-based multi-physics simulation package, and compare our results to existing work. These simulations model a star cluster beginning with a King model distribution and a selection of power-law initial mass functions and contain a tidal cutoff. They are evolved using collisional stellar dynamics and include mass loss due to stellar evolution. After studying and understanding that the differences between AMUSE results and results from previous studies are understood, we explored the variation in cluster lifetimes due to the random realization noisemore » introduced by transforming a King model to specific initial conditions. This random realization noise can affect the lifetime of a simulated star cluster by up to 30%. Two modes of star cluster dissolution were identified: a mass evolution curve that contains a runaway cluster dissolution with a sudden loss of mass, and a dissolution mode that does not contain this feature. We refer to these dissolution modes as 'dynamical' and 'relaxation' dominated, respectively. For Salpeter-like initial mass functions, we determined the boundary between these two modes in terms of the dynamical and relaxation timescales.« less

A Review: Pharmaceutical and Pharmacokinetic Aspect of Nanocrystalline Suspensions.

PubMed

Shah, Dhaval A; Murdande, Sharad B; Dave, Rutesh H

2016-01-01

Nanocrystals have emerged as a potential formulation strategy to eliminate the bioavailability-related problems by enhancing the initial dissolution rate and moderately super-saturating the thermodynamic solubility. This review contains an in-depth knowledge of, the processing method for formulation, an accurate quantitative assessment of the solubility and dissolution rates and their correlation to observe pharmacokinetic data. Poor aqueous solubility is considered the major hurdle in the development of pharmaceutical compounds. Because of a lack of understanding with regard to the change in the thermodynamic and kinetic properties (i.e., solubility and dissolution rate) upon nanosizing, we critically reviewed the literatures for solubility determination to understand the significance and accuracy of the implemented analytical method. In the latter part, we reviewed reports that have quantitatively studied the effect of the particle size and the surface area change on the initial dissolution rate enhancement using alternative approaches besides the sink condition dissolution. The lack of an apparent relationship between the dissolution rate enhancement and the observed bioavailability are discussed by reviewing the reported in vivo data on animal models along with the particle size and food effect. The review will provide comprehensive information to the pharmaceutical scientist in the area of nanoparticulate drug delivery.

Carbon dioxide adsorption in Brazilian coals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jose Luciano Soares; Andre L.B. Oberziner; Humberto J. Jose

Carbon dioxide (CO{sub 2}) is one of the most important greenhouse gases. In the period between 1980 and 1998, CO{sub 2} emissions increased more than 21% and projections suggest that the emissions will continue to increase globally by 2.2% between 2000 and 2020 and 3.3% in the developed countries. The sequestration of CO{sub 2} in deep unminable coal beds is one of the more promising of several methods of geological sequestration that are currently being investigated. CO{sub 2} can adsorb onto coal, and there are several studies demonstrating that CO{sub 2} dissolves in coals and swells them. At very lowmore » pressures (P {lt} 1 bar), CO{sub 2} dissolution does not seem to be a problem; however, high pressures are necessary for CO{sub 2} sequestration (P {gt} 50 bar). In this study, we evaluated the kinetics and equilibrium of sorption of CO{sub 2} on Brazilian coals at low pressures. The adsorption equilibrium isotherm at room temperature (30{sup o}C) was measured through the static method. The results showed that the Freundlich model or the Langmuir model is suitable to describe the equilibrium experimental results. The CO{sub 2} adsorption capacity of Brazilian coals are in the range of 0.089-0.186 mmol CO{sub 2}/g, which are typical values for coals with high ash content. The dynamics of adsorption in a fixed-bed column that contains granular coal (particle sizes of 0.8, 2.4, and 4.8 mm) showed that the adsorption rate is fast and a mathematical model was developed to describe the CO{sub 2} dynamics of the adsorption in a fixed-bed column. The linear driving force (LDF) was used to describe the rate of adsorption and the mass-transfer constants of the LDF model (K{sub s}) are in the range of 1.0-2.0 min{sup -1}. 29 refs., 5 figs., 3 tabs.« less

Uranium carbide dissolution in nitric solution: Sonication vs. silent conditions

NASA Astrophysics Data System (ADS)

Virot, Matthieu; Szenknect, Stéphanie; Chave, Tony; Dacheux, Nicolas; Moisy, Philippe; Nikitenko, Sergey I.

2013-10-01

The dissolution of uranium carbide (UC) in nitric acid media is considered by means of power ultrasound (sonication) or magnetic stirring. The induction period required to initiate UC dissolution was found to be dramatically shortened when sonicating a 3 M nitric solution (Ar, 20 kHz, 18 W cm-2, 20 °C). At higher acidity, magnetic stirring offers faster dissolution kinetics compared to sonication. Ultrasound-assisted UC dissolution is found to be passivated after ∼60% dissolution and remains incomplete whatever the acidity which is confirmed by ICP-AES, LECO and SEM-EDX analyses. In general, the kinetics of UC dissolution is linked to the in situ generation of nitrous acid in agreement with the general mechanism of UC dissolution; the nitrous acid formation is reported to be faster under ultrasound at low acidity due to the nitric acid sonolysis. The carbon balance shared between the gaseous, liquid, and solid phases is strongly influenced by the applied dissolution procedure and HNO3 concentration.

Western Canadian coals to eastern markets: to and through Thunder Bay terminal

DOE Office of Scientific and Technical Information (OSTI.GOV)

Michaud, M.; Farrugia, M.A.

Remoteness of western Canadian coals has always been a barrier to the use of Canadian coals domestically. However, the world energy crunch, increased mining costs, stricter environmental controls, labor shortages, etc., are such that by 1980 a shortfall from traditional U.S. sources will prevail. Of necessity, Canada must then bring western coals east, requiring major new transportation initiatives. CN, CP Rail and Neptune Terminals are proceeding jointly with the design of a $30 million, fully automated, coal terminal at Thunder Bay. This element forms part of a $400 million integral transportation system to open new lines, improve trackage, acquire rollingmore » stock and ships, for an initial capacity of 3 million tpy.« less

43 CFR 3420.2 - Regional leasing levels.

Code of Federal Regulations, 2011 CFR

2011-10-01

... coal teams shall be the forum through which initial leasing level recommendations are transmitted to the Secretary. Initial leasing level recommendations shall be developed as follows: (1) The... shall be requested by the regional coal team chairperson to provide comments and recommendations...

Coal-water slurry sprays from an electronically controlled accumulator fuel injection system: Break-up distances and times

NASA Astrophysics Data System (ADS)

Caton, J. A.; Payne, S. E.; Terracina, D. P.; Kihm, K. D.

Experiments have been completed to characterize coal-water slurry sprays from an electronically-controlled accumulator fuel injection system of a diesel engine. The sprays were injected into a pressurized chamber equipped with windows. High speed movies, fuel pressures, and needle lifts were obtained as a function of time, orifice diameter, coal loading, gas density in the chamber, and accumulator fuel pressure. For the base conditions (50% by mass coal loading, 0.4 mm diameter nozzle hole, coal-water slurry pressure of 82 MPa (12,000 psi), and a chamber density of 25 kg/m(exp 3)), the break-up time was 0.30 ms. An empirical correlation for spray tip penetration, break-up time, and initial jet velocity was developed. For the conditions of this study, the spray tip penetration and initial jet velocity were 15% greater for coal-water slurry than for diesel fuel or water. Results of this study and the correlation are specific to the tested coal-water slurry and are not general for other coal-water slurry fuels.

Experimental Study of the Influence of the Concentration of Organic Water-Coal Fuel Components on the Integral Ignition Characteristics

NASA Astrophysics Data System (ADS)

Vershinina, K. Yu.; Kuznetsov, G. V.; Strizhak, P. A.

2017-01-01

To enlarge the power raw material base, the processes of stable initiation of combustion of drops of organic watercoal fuels have been investigated. For the main components, we used filter cakes (coal processing waste), anthracite, bituminous and brown coals of brands D and B2, water, and spent machine, turbine, and transformer oils. We have established the influence of concentrations of components on the minimum (limiting) ignition temperatures of organic water-coal fuels and the ignition delay times of drops of fuel components with initial sizes of 0.25-1.5 mm. Investigations were carried out for oxidizer temperatures of 600-1100 K and its velocities of 0.5-5 m/s characteristic of units, aggregates, and large and small power plants. We have determined the characteristic differences of organic water-coal fuel from water-coal fuel and the close laws of the investigated processes for these fuels.

PRODUCTION AND SCREENING OF CARBON PRODUCTS PRECURSORS FROM COAL

DOE Office of Scientific and Technical Information (OSTI.GOV)

Caulton L. Irwin

2001-05-31

The authors have examined effects of blending a raw coal extract (EXT) with an extracted coal-tar pitch (ECTP). Previous reports were concerned with the addition of 15 wt% EXT, or less, on the physical characteristics of the blend and on the development of optical texture following carbonization. Two additional blends of ECTP and EXT were prepared at the 30 and 50 wt% EXT content using a procedure already described. The characteristics of the blends are presented. The density for these blended materials is not much different than the density for the blends reported earlier. The softening point temperature for themore » 30 wt% EXT increased to over 200 C while the softening point temperature for the 50 wt% EXT blend was too high to be determined by the Mettler method. Coke yields approximately follow the law of mixtures. The optical texture of the green cokes for the 30 and 50 wt% EXT blends is shown. Though the optical texture of the green cokes was not significantly affected where the level of EXT is 15 wt% or less, larger proportions of EXT exert a marked reduction in anisotropy. The co-processing of coal with petroleum residues or other heavy hydrocarbons at elevated temperature and pressure has received considerable attention in the research community as a means to upgrade simultaneously coal and byproducts. Heavy hydrocarbons can function as sources of hydrogen, as well as performing as a medium for dissolution and dispersion of coal fragments. However, the focus of much of the prior research has been on developing fuels, distillable liquids, or synthetic crudes. Comparatively little effort has been deliberately directed toward the production of heavier, non-distillable materials which could perform as binder and extender pitches, impregnants, or feedstocks for cokes and other carbons.« less

Dissolution of Platinum in the Operational Range of Fuel Cells

PubMed Central

Keeley, Gareth P.; Geiger, Simon; Zeradjanin, Aleksandar R.; Hodnik, Nejc; Kulyk, Nadiia

2015-01-01

Abstract One of the most important practical issues in low‐temperature fuel‐cell catalyst degradation is platinum dissolution. According to the literature, it initiates at 0.6–0.9 VRHE, whereas previous time‐ and potential‐resolved inductively coupled plasma mass spectrometry (ICP–MS) experiments, however, revealed dissolution onset at only 1.05 VRHE. In this manuscript, the apparent discrepancy is addressed by investigating bulk and nanoparticulated catalysts. It is shown that, given enough time for accumulation, traces of platinum can be detected at potentials as low as 0.85 VRHE. At these low potentials, anodic dissolution is the dominant process, whereas, at more positive potentials, more platinum dissolves during the oxide reduction after accumulation. Interestingly, the potential and time dissolution dependence is similar for both types of electrode. Dissolution processes are discussed with relevance to fuel‐cell operation and plausible dissolution mechanisms are considered. PMID:27525206

Dewetting kinetics of metallic liquid films: Competition between unbalanced Young's force and dissolutive reaction

NASA Astrophysics Data System (ADS)

Lu, Gui; Lin, Lin; Hui, Sheng; Wang, Shuo-Lin; Wang, Xiao-Dong; Lee, Duu-Jong

2017-11-01

Dewetting kinetics of Al and NiAl metallic liquid films on NiAl (1 0 0) substrates was studied using molecular dynamics simulations. A new dewetting-spreading transitional behavior was observed for high temperature dewetting. The dewetting-spreading transition comes from the competition between unbalanced Young's force and dissolutive reaction. Without dissolutive reaction, liquid films keep dewetting, but immediately turn into spreading when the dissolutive reaction involved. The dissolutive reaction depends on the initial Ni atom contents rather than the contact areas of dewetting films. The far-away-from saturated Ni content is the main mechanism which accelerates the wetting and reverses the dewetting process at high temperatures.

Dissolution and Precipitation Behaviour during Continuous Heating of Al–Mg–Si Alloys in a Wide Range of Heating Rates

PubMed Central

Osten, Julia; Milkereit, Benjamin; Schick, Christoph; Kessler, Olaf

2015-01-01

In the present study, the dissolution and precipitation behaviour of four different aluminium alloys (EN AW-6005A, EN AW-6082, EN AW-6016, and EN AW-6181) in four different initial heat treatment conditions (T4, T6, overaged, and soft annealed) was investigated during heating in a wide dynamic range. Differential scanning calorimetry (DSC) was used to record heating curves between 20 and 600 °C. Heating rates were studied from 0.01 K/s to 5 K/s. We paid particular attention to control baseline stability, generating flat baselines and allowing accurate quantitative evaluation of the resulting DSC curves. As the heating rate increases, the individual dissolution and precipitation reactions shift to higher temperatures. The reactions during heating are significantly superimposed and partially run simultaneously. In addition, precipitation and dissolution reactions are increasingly suppressed as the heating rate increases, whereby exothermic precipitation reactions are suppressed earlier than endothermic dissolution reactions. Integrating the heating curves allowed the enthalpy levels of the different initial microstructural conditions to be quantified. Referring to time–temperature–austenitisation diagrams for steels, continuous heating dissolution diagrams for aluminium alloys were constructed to summarise the results in graphical form. These diagrams may support process optimisation in heat treatment shops.

43 CFR 3430.2-1 - Initial showing.

Code of Federal Regulations, 2011 CFR

2011-10-01

... Public Lands: Interior Regulations Relating to Public Lands (Continued) BUREAU OF LAND MANAGEMENT...-1 Initial showing. All preference right coal lease applications shall have contained or shall have been supplemented by the timely submission of: (a) Information on the quantity and quality of the coal...

Anion-Dependent Potential Precycling Effects on Lithium Deposition/Dissolution Reaction Studied by an Electrochemical Quartz Crystal Microbalance.

PubMed

Smaran, Kumar Sai; Shibata, Sae; Omachi, Asami; Ohama, Ayano; Tomizawa, Eika; Kondo, Toshihiro

2017-10-19

The electrochemical quartz crystal microbalance technique was employed to study the initial stage of the electrodeposition and dissolution of lithium utilizing three kinds of electrolyte solutions such as LiPF 6 , LiTFSI, or LiFSI in tetraglyme. The native-SEI (solid-electrolyte interphase) formed by a potential prescan before lithium deposition/dissolution in all three solutions. Simultaneous additional SEI (add-SEI) deposition and its dissolution with lithium deposition and dissolution, respectively, were observed in LiPF 6 and LiTFSI. Conversely, the add-SEI dissolution with lithium deposition and its deposition with lithium dissolution were observed in LiFSI. Additional potential precycling resulted in the accumulation of a "pre-SEI" layer over the native-SEI layer in all of the solutions. With the pre-SEI, only lithium deposition/dissolution were significantly observed in LiTFSI and LiFSI. On the basis of the potential dependences of the mass and resistance changes, the anion-dependent effects of such a pre-SEI layer presence/absence on the lithium deposition/dissolution processes were discussed.

20 CFR 726.304 - Notice of initial assessment.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 20 Employees' Benefits 3 2010-04-01 2010-04-01 false Notice of initial assessment. 726.304 Section 726.304 Employees' Benefits EMPLOYMENT STANDARDS ADMINISTRATION, DEPARTMENT OF LABOR FEDERAL COAL MINE HEALTH AND SAFETY ACT OF 1969, AS AMENDED BLACK LUNG BENEFITS; REQUIREMENTS FOR COAL MINE OPERATOR'S...

Converter slag-coal cinder columns for the removal of phosphorous and other pollutants.

PubMed

Yang, Jian; Wang, Su; Lu, Zhibo; Yang, Jian; Lou, Shanjie

2009-08-30

A mixture of converter slag and coal cinder as adsorbent for the removal of phosphorous and other pollutants was studied in the paper. The maximum P adsorption capacity, pH of solution, contact time and initial phosphate concentration were evaluated in batch experiments for the two materials firstly. The data of P sorption were best fitted to Langumir equation, and the maximum adsorption capacities of converter slag and coal cinder were 2.417 and 0.398 mg P/g, respectively. The pH of solutions with converter slag and coal cinder changed dramatically with time and closed to 8 in 8h, and the influence of initial pH on phosphate removal by coal cinder was more significant than by converter slag. Phosphate removal rate by converter slag decreased with increase of initial phosphate concentrations. Subsequently, two flow-through columns (Column 1#, V(converter slag):V(coal cinder)=1:5; Column 2#, V(converter slag):V(coal cinder)=1:3) were operated for the removal of phosphorous and other pollutants from the effluents of a vermifilter for nearly eleven months. Results indicated the average removal efficiency of total phosphorus, dissolved phosphorus, COD and NH(4)(+)-N by Column 1# were 44%, 56%, 31% and 67%, and by Column 2# were 42%, 54%, 24% and 57%, respectively. Column 1# had higher removal efficiency for P and other pollutants.

Estimating the time for dissolution of spent fuel exposed to unlimited water

DOE Office of Scientific and Technical Information (OSTI.GOV)

Leider, H.R.; Nguyen, S.N.; Stout, R.B.

1991-12-01

The release of radionuclides from spent fuel cannot be precisely predicted at this point because a satisfactory dissolution model based on specific chemical processes is not yet available. However, preliminary results on the dissolution rate of UO{sub 2} and spent fuel as a function of temperature and water composition have recently been reported. This information, together with data on fragment size distribution of spent fuel, are used to estimate the dissolution response of spent fuel in excess flowing water within the framework of a simple model. In this model, the reaction/dissolution front advances linearly with time and geometry is preserved.more » This also estimates the dissolution rate of the bulk of the fission products and higher actinides, which are uniformly distributed in the UO{sub 2} matrix and are presumed to dissolve congruently. We have used a fuel fragment distribution actually observed to calculate the time for total dissolution of spent fuel. A worst-case estimate was also made using the initial (maximum) rate of dissolution to predict the total dissolution time. The time for total dissolution of centimeter size particles is estimated to be 5.5 {times} 10{sup 4} years at 25{degrees}C.« less

Mechanism of Urea Crystal Dissolution in Water from Molecular Dynamics Simulation.

PubMed

Anand, Abhinav; Patey, G N

2018-01-25

Molecular dynamics simulations are used to determine the mechanism of urea crystal dissolution in water under sink conditions. Crystals of cubic and tablet shapes are considered, and results are reported for four commonly used water models. The dissolution rates for different water models can differ considerably, but the overall dissolution mechanism remains the same. Urea dissolution occurs in three stages: a relatively fast initial stage, a slower intermediate stage, and a final stage. We show that the long intermediate stage is well described by classical rate laws, which assume that the dissolution rate is proportional to the active surface area. By carrying out simulations at different temperatures, we show that urea dissolution is an activated process, with an activation energy of ∼32 kJ mol -1 . Our simulations give no indication of a significant diffusion layer, and we conclude that the detachment of molecules from the crystal is the rate-determining step for dissolution. The results we report for urea are consistent with earlier observations for the dissolution of NaCl crystals. This suggests that the three-stage mechanism and classical rate laws might apply to the dissolution of other ionic and molecular crystals.

Viscosity Determination of Molten Ash from Low-Grade US Coals

DOE PAGES

Zhu, Jingxi; Nakano, Jinichiro; Kaneko, Tetsuya Kenneth; ...

2012-10-01

In entrained slagging gasifiers, the fluidity of the molten ash is a critical factor for process control since it affects slag formation, the capture of inorganic constituents, refractory wear, and slag drainage along the gasification chamber walls. The use of western coal, or mixtures of eastern and western coals as gasifier feedstock, is likely to occur as western coals become available and technological issues that hinder their use are being resolved. In the present work, the viscosity of synthetic slags with ash chemistries simulating the western U.S. coals, was experimentally measured at a Po 2 = 10 - 8 atmmore » in the temperature range of 1773–1573 K (1500–1300 °C) using a rotating-bob viscometer. Alumina spindles and containment crucibles of both alumina and zirconia were used. Crystallization studies of this slag using a confocal scanning laser microscope found that a (Mg,Fe)Al 2O 4-based spinel precipitated at temperatures below 1723 K (1450 °C), and this agreed with FactSage equilibrium phase prediction. The same spinels were observed in the post-viscometry experiment slags when ZrO 2 crucibles were used and assumed to be in equilibrium with the slag at the higher temperatures. Zirconia dissolution resulted in a slight increase in the solid fraction present in slags at lower temperatures, compared to spinel fraction. Crystal precipitation changed the apparent activation energy and required a longer stabilization times for viscosity measurements. The viscosity results were used in predictive equations based on Veytsman and Einstein's models, with critical nucleation temperatures and the solid fraction calculated with FactSage. In the simulated eastern/western coal feedstock blends based on ash compositions, the fractions of the solid precipitates were also calculated using the thermodynamic program FactSage for each blend composition, and the plastic viscosity of each eastern/western coal slag blend was predicted using Veytsman's model and compared to available experimental data.« less

Coal Rank and Stratigraphy of Pennsylvanian Coal and Coaly Shale Samples, Young County, North-Central Texas

USGS Publications Warehouse

Guevara, Edgar H.; Breton, Caroline; Hackley, Paul C.

2007-01-01

Vitrinite reflectance measurements were made to determine the rank of selected subsurface coal and coaly shale samples from Young County, north-central Texas, for the National Coal Resources Database System State Cooperative Program conducted by the Bureau of Economic Geology at The University of Texas at Austin. This research is the continuation of a pilot study that began in adjacent Archer County, and forms part of a larger investigation of the coalbed methane resource potential of Pennsylvanian coals in north-central Texas. A total of 57 samples of coal and coaly shale fragments were hand-picked from drill cuttings from depths of about 2,000 ft in five wells, and Ro determinations were made on an initial 10-sample subset. Electric-log correlation of the sampled wells indicates that the collected samples represent coal and coaly shale layers in the Strawn (Pennsylvanian), Canyon (Pennsylvanian), and Cisco (Pennsylvanian-Permian) Groups. Coal rank in the initial sample subset ranges from lignite (Ro=0.39), in a sample from the Cisco Group at a depth of 310 to 320 ft, to high volatile bituminous A coal (Ro=0.91) in a sample from the lower part of the Canyon Group at a depth of 2,030 to 2,040 ft.

Estimation of Crack Initiation and Propagation Thresholds of Confined Brittle Coal Specimens Based on Energy Dissipation Theory

NASA Astrophysics Data System (ADS)

Ning, Jianguo; Wang, Jun; Jiang, Jinquan; Hu, Shanchao; Jiang, Lishuai; Liu, Xuesheng

2018-01-01

A new energy-dissipation method to identify crack initiation and propagation thresholds is introduced. Conventional and cyclic loading-unloading triaxial compression tests and acoustic emission experiments were performed for coal specimens from a 980-m deep mine with different confining pressures of 10, 15, 20, 25, 30, and 35 MPa. Stress-strain relations, acoustic emission patterns, and energy evolution characteristics obtained during the triaxial compression tests were analyzed. The majority of the input energy stored in the coal specimens took the form of elastic strain energy. After the elastic-deformation stage, part of the input energy was consumed by stable crack propagation. However, with an increase in stress levels, unstable crack propagation commenced, and the energy dissipation and coal damage were accelerated. The variation in the pre-peak energy-dissipation ratio was consistent with the coal damage. This new method demonstrates that the crack initiation threshold was proportional to the peak stress ( σ p) for ratios that ranged from 0.4351 to 0.4753 σ p, and the crack damage threshold ranged from 0.8087 to 0.8677 σ p.

Coal cleaning: An underutilized solution?

DOE Office of Scientific and Technical Information (OSTI.GOV)

Godfrey, R.L.

1995-12-31

Custom Coals Corporation is based in Pittsburgh, Pennsylvania. It is involved in the construction and operation of advanced coal cleaning facilities. The company has initially chosen to focus on Pennsylvania`s vast reserves of coal, because these coal provide a superior feedstock for the Technology. In a $76 million project co-sponsored by the U.S. Department of Energy, Custom Coals is constructing its first coal cleaning facility. The DOE chose to participate with the company in the project pursuant to a competition it sponsored under Round IV of Its Clean Cod Technology program. Thirty-one companies submitted 33 projects seeking approximately $2.3 billionmore » of funding against the $600 million available. The company`s project was one of nine proposals accepted and was the only pre-combustion cleaning technology awarded. The project includes both the construction of a 500 ton per hour coal cleaning facility utilizing the company`s proprietary technologies and a series of power plant test bums on a variety of U.S. coals during a 12-month demonstration program. Three U.S. coal seams - Sewickley, Lower Freeport and Illinois No. 5 - will supply the initial feedstock for the demonstration project. These seams represent a broad range of raw cod qualifies. The processed coals will then be distributed to a number of generating stations for combustion. The 300 megawatt Martins Creek Plant of Pennsylvania Power & Light Co., near Allentown, Pennsylvania, will burn Carefree Coal, the 60 megawatt Whitewater Valley Power Station of Richmond Power and Light (in Indiana) and the Ashtabula, Ohio unit of Centerior Energy will burn Self-Scrubbing Coal. Following these demonstrations, the plant will begin full-scale commercial operation, providing two million tons of Pennsylvania compliance coals to electric power utilities.« less

30 CFR 700.4 - Responsibility.

Code of Federal Regulations, 2013 CFR

2013-07-01

... concurrence of the Federal surface managing agency as unsuitable for all or certain types of surface coal... the regulation of surface coal mining and reclamation operations under the initial regulatory program... coal mining and reclamation operations on Federal lands in accordance with 30 CFR part 745. (e) The...

30 CFR 700.4 - Responsibility.

Code of Federal Regulations, 2010 CFR

2010-07-01

... concurrence of the Federal surface managing agency as unsuitable for all or certain types of surface coal... the regulation of surface coal mining and reclamation operations under the initial regulatory program... coal mining and reclamation operations on Federal lands in accordance with 30 CFR part 745. (e) The...

30 CFR 700.4 - Responsibility.

Code of Federal Regulations, 2012 CFR

2012-07-01

... concurrence of the Federal surface managing agency as unsuitable for all or certain types of surface coal... the regulation of surface coal mining and reclamation operations under the initial regulatory program... coal mining and reclamation operations on Federal lands in accordance with 30 CFR part 745. (e) The...

30 CFR 700.4 - Responsibility.

Code of Federal Regulations, 2014 CFR

2014-07-01

... concurrence of the Federal surface managing agency as unsuitable for all or certain types of surface coal... the regulation of surface coal mining and reclamation operations under the initial regulatory program... coal mining and reclamation operations on Federal lands in accordance with 30 CFR part 745. (e) The...

30 CFR 700.4 - Responsibility.

Code of Federal Regulations, 2011 CFR

2011-07-01

... concurrence of the Federal surface managing agency as unsuitable for all or certain types of surface coal... the regulation of surface coal mining and reclamation operations under the initial regulatory program... coal mining and reclamation operations on Federal lands in accordance with 30 CFR part 745. (e) The...

Reaction paths and equilibrium end-points in solid-solution aqueous-solution systems

USGS Publications Warehouse

Glynn, P.D.; Reardon, E.J.; Plummer, Niel; Busenberg, E.

1990-01-01

Equations are presented describing equilibrium in binary solid-solution aqueous-solution (SSAS) systems after a dissolution, precipitation, or recrystallization process, as a function of the composition and relative proportion of the initial phases. Equilibrium phase diagrams incorporating the concept of stoichiometric saturation are used to interpret possible reaction paths and to demonstrate relations between stoichiometric saturation, primary saturation, and thermodynamic equilibrium states. The concept of stoichiometric saturation is found useful in interpreting and putting limits on dissolution pathways, but there currently is no basis for possible application of this concept to the prediction and/ or understanding of precipitation processes. Previously published dissolution experiments for (Ba, Sr)SO4 and (Sr, Ca)C??O3orth. solids are interpreted using equilibrium phase diagrams. These studies show that stoichiometric saturation can control, or at least influence, initial congruent dissolution pathways. The results for (Sr, Ca)CO3orth. solids reveal that stoichiometric saturation can also control the initial stages of incongruent dissolution, despite the intrinsic instability of some of the initial solids. In contrast, recrystallisation experiments in the highly soluble KCl-KBr-H2O system demonstrate equilibrium. The excess free energy of mixing calculated for K(Cl, Br) solids is closely modeled by the relation GE = ??KBr??KClRT[a0 + a1(2??KBr-1)], where a0 is 1.40 ?? 0.02, a1, is -0.08 ?? 0.03 at 25??C, and ??KBr and ??KCl are the mole fractions of KBr and KCl in the solids. The phase diagram constructed using this fit reveals an alyotropic maximum located at ??KBr = 0.676 and at a total solubility product, ???? = [K+]([Cl-] + [Br-]) = 15.35. ?? 1990.

In vitro dynamic solubility test: influence of various parameters.

PubMed Central

Thélohan, S; de Meringo, A

1994-01-01

This article discusses the dissolution of mineral fibers in simulated physiological fluids (SPF), and the parameters that affect the solubility measurement in a dynamic test where an SPF runs through a cell containing fibers (Scholze and Conradt test). Solutions simulate either the extracellular fluid (pH 7.6) or the intracellular fluid (pH 4.5). The fibers have various chemical compositions and are either continuously drawn or processed as wool. The fiber solubility is determined by the amount of SiO2 (and occasionally other ions) released in the solution. Results are stated as percentage of the initial silica content released or as dissolution rate v in nm/day. The reproducibility of the test is higher with the less soluble fibers (10% solubility), than with highly soluble fibers (20% solubility). The influence of test parameters, including SPF, test duration, and surface area/volume (SA/V), has been studied. The pH and the inorganic buffer salts have a major influence: industrial glasswool composition is soluble at pH 7.6 but not at pH 4.5. The opposite is true for rock- (basalt) wool composition. For slightly soluble fibers, the dissolution rate v remains constant with time, whereas for highly soluble fibers, the dissolution rate decreases rapidly. The dissolution rates believed to occur are v1, initial dissolution rate, and v2, dissolution rate of the residual fibers. The SA of fibers varies with the mass of the fibers tested, or with the fiber diameter at equal mass. Volume, V, is the chosen flow rate. An increase in the SA/V ratio leads to a decrease in the dissolution rate.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7882964

In vitro dynamic solubility test: influence of various parameters.

PubMed

Thélohan, S; de Meringo, A

1994-10-01

This article discusses the dissolution of mineral fibers in simulated physiological fluids (SPF), and the parameters that affect the solubility measurement in a dynamic test where an SPF runs through a cell containing fibers (Scholze and Conradt test). Solutions simulate either the extracellular fluid (pH 7.6) or the intracellular fluid (pH 4.5). The fibers have various chemical compositions and are either continuously drawn or processed as wool. The fiber solubility is determined by the amount of SiO2 (and occasionally other ions) released in the solution. Results are stated as percentage of the initial silica content released or as dissolution rate v in nm/day. The reproducibility of the test is higher with the less soluble fibers (10% solubility), than with highly soluble fibers (20% solubility). The influence of test parameters, including SPF, test duration, and surface area/volume (SA/V), has been studied. The pH and the inorganic buffer salts have a major influence: industrial glasswool composition is soluble at pH 7.6 but not at pH 4.5. The opposite is true for rock- (basalt) wool composition. For slightly soluble fibers, the dissolution rate v remains constant with time, whereas for highly soluble fibers, the dissolution rate decreases rapidly. The dissolution rates believed to occur are v1, initial dissolution rate, and v2, dissolution rate of the residual fibers. The SA of fibers varies with the mass of the fibers tested, or with the fiber diameter at equal mass. Volume, V, is the chosen flow rate. An increase in the SA/V ratio leads to a decrease in the dissolution rate.(ABSTRACT TRUNCATED AT 250 WORDS)

Addressable Direct-Write Nanoscale Filament Formation and Dissolution by Nanoparticle-Mediated Bipolar Electrochemistry.

PubMed

Crouch, Garrison M; Han, Donghoon; Fullerton-Shirey, Susan K; Go, David B; Bohn, Paul W

2017-05-23

Nanoscale conductive filaments, usually associated with resistive memory or memristor technology, may also be used for chemical sensing and nanophotonic applications; however, realistic implementation of the technology requires precise knowledge of the conditions that control the formation and dissolution of filaments. Here we describe and characterize an addressable direct-write nanoelectrochemical approach to achieve repeatable formation/dissolution of Ag filaments across a ∼100 nm poly(ethylene oxide) (PEO) film containing either Ag + alone or Ag + together with 50 nm Ag-nanoparticles acting as bipolar electrodes. Using a conductive AFM tip, formation occurs when the PEO film is subjected to a forward bias, and dissolution occurs under reverse bias. Formation-dissolution kinetics were studied for three film compositions: Ag|PEO-Ag + , Ag|poly(ethylene glycol) monolayer-PEO-Ag + , and Ag|poly(ethylene glycol) monolayer-PEO-Ag + /Ag-nanoparticle. Statistical analysis shows that the distribution of formation times exhibits Gaussian behavior, and the fastest average initial formation time occurs for the Ag|PEO-Ag + system. In contrast, formation in the presence of Ag nanoparticles likely proceeds by a noncontact bipolar electrochemical mechanism, exhibiting the slowest initial filament formation. Dissolution times are log-normal for all three systems, and repeated reformation of filaments from previously formed structures is characterized by rapid regrowth. The direct-write bipolar electrochemical deposition/dissolution strategy developed here presents an approach to reconfigurable, noncontact in situ wiring of nanoparticle arrays-thereby enabling applications where actively controlled connectivity of nanoparticle arrays is used to manipulate nanoelectronic and nanophotonic behavior. The system further allows for facile manipulation of experimental conditions while simultaneously characterizing surface conditions and filament formation/dissolution kinetics.

Convective Instability and Mass Transport of the Diffusion Layer in CO2 Sequestration

NASA Astrophysics Data System (ADS)

Backhaus, S.

2011-12-01

The long-term fate of supercritical (sc) CO2 in saline aquifers is critical to the security of carbon sequestration, an important option for eliminating or reducing the emissions of this most prevalent greenhouse gas. scCO2 is less dense than brine and floats to the top of the aquifer where it is trapped in a metastable state by a geologic feature such as a low permeability cap rock. Dissolution into the underlying brine creates a CO2-brine mixture that is denser than brine, eliminating buoyancy and removing the threat of CO2 escaping back to the atmosphere. If molecular diffusion were the only dissolution mechanism, the CO2 waste stream from a typical large coal-fired electrical power plant may take upward of 10,000 years to no longer pose a threat, however, a convective instability of the dense diffusion boundary layer between the scCO2 and the brine can dramatically increase the dissolution rates, shortening the lifetime of the scCO2 waste pool. We present results of 2D and 3D similitude-correct, laboratory-scale experiments using an analog fluid system. The experiments and flow visualization reveal the onset of the convective instability, the dynamics of the fluid flows during the convective processes, and the long-term mass transfer rates.

Experiments and modeling of variably permeable carbonate reservoir samples in contact with CO₂-acidified brines

DOE PAGES

Smith, Megan M.; Hao, Yue; Mason, Harris E.; ...

2014-12-31

Reactive experiments were performed to expose sample cores from the Arbuckle carbonate reservoir to CO₂-acidified brine under reservoir temperature and pressure conditions. The samples consisted of dolomite with varying quantities of calcite and silica/chert. The timescales of monitored pressure decline across each sample in response to CO₂ exposure, as well as the amount of and nature of dissolution features, varied widely among these three experiments. For all samples cores, the experimentally measured initial permeability was at least one order of magnitude or more lower than the values estimated from downhole methods. Nondestructive X-ray computed tomography (XRCT) imaging revealed dissolution featuresmore » including “wormholes,” removal of fracture-filling crystals, and widening of pre-existing pore spaces. In the injection zone sample, multiple fractures may have contributed to the high initial permeability of this core and restricted the distribution of CO₂-induced mineral dissolution. In contrast, the pre-existing porosity of the baffle zone sample was much lower and less connected, leading to a lower initial permeability and contributing to the development of a single dissolution channel. While calcite may make up only a small percentage of the overall sample composition, its location and the effects of its dissolution have an outsized effect on permeability responses to CO₂ exposure. The XRCT data presented here are informative for building the model domain for numerical simulations of these experiments but require calibration by higher resolution means to confidently evaluate different porosity-permeability relationships.« less

Coal Mine Dust Desquamative Chronic Interstitial Pneumonia: A Precursor of Dust-Related Diffuse Fibrosis and of Emphysema.

PubMed

Jelic, Tomislav M; Estalilla, Oscar C; Sawyer-Kaplan, Phyllis R; Plata, Milton J; Powers, Jeremy T; Emmett, Mary; Kuenstner, John T

2017-07-01

Diseases associated with coal mine dust continue to affect coal miners. Elucidation of initial pathological changes as a precursor of coal dust-related diffuse fibrosis and emphysema, may have a role in treatment and prevention. To identify the precursor of dust-related diffuse fibrosis and emphysema. Birefringent silica/silicate particles were counted by standard microscope under polarized light in the alveolar macrophages and fibrous tissue in 25 consecutive autopsy cases of complicated coal worker's pneumoconiosis and in 21 patients with tobacco-related respiratory bronchiolitis. Coal miners had 331 birefringent particles/high power field while smokers had 4 (p<0.001). Every coal miner had intra-alveolar macrophages with silica/silicate particles and interstitial fibrosis ranging from minimal to extreme. All coal miners, including those who never smoked, had emphysema. Fibrotic septa of centrilobular emphysema contained numerous silica/silicate particles while only a few were present in adjacent normal lung tissue. In coal miners who smoked, tobacco-associated interstitial fibrosis was replaced by fibrosis caused by silica/silicate particles. The presence of silica/silicate particles and anthracotic pigment-laden macrophages inside the alveoli with various degrees of interstitial fibrosis indicated a new disease: coal mine dust desquamative chronic interstitial pneumonia, a precursor of both dust-related diffuse fibrosis and emphysema. In studied coal miners, fibrosis caused by smoking is insignificant in comparison with fibrosis caused by silica/silicate particles. Counting birefringent particles in the macrophages from bronchioalveolar lavage may help detect coal mine dust desquamative chronic interstitial pneumonia, and may initiate early therapy and preventive measures.

43 CFR 3420.1-2 - Call for coal resource and other resource information.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false Call for coal resource and other resource... Competitive Leasing § 3420.1-2 Call for coal resource and other resource information. (a) Prior to or as part of the initiation or update of a land use plan or land use analysis, a Call for Coal and Other...

43 CFR 3420.1-2 - Call for coal resource and other resource information.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 43 Public Lands: Interior 2 2012-10-01 2012-10-01 false Call for coal resource and other resource... Competitive Leasing § 3420.1-2 Call for coal resource and other resource information. (a) Prior to or as part of the initiation or update of a land use plan or land use analysis, a Call for Coal and Other...

Economic and Technological Role of Kuzbass Industry in the Implementation of National Energy Strategy of Russian Federation

NASA Astrophysics Data System (ADS)

Zhironkin, S. A.; Khoreshok, A. A.; Tyulenev, M. A.; Barysheva, G. A.; Hellmer, M. C.

2016-08-01

This article describes the problems and prospects of development of coal mining in Kuzbass - the center of coal production in Siberia and Russia, in the framework of the major initiatives of the National Energy Strategy for the period until 2035. The structural character of the regional coal industry problems, caused by decline in investment activity, high level of fixed assets depreciation, slow development of deep coal processing and technological reduction of coal mining is shown.

Hydrochemical characteristics and quality assessment of deep groundwater from the coal-bearing aquifer of the Linhuan coal-mining district, Northern Anhui Province, China.

PubMed

Lin, Man-Li; Peng, Wei-Hua; Gui, He-Rong

2016-04-01

There is little information available about the hydrochemical characteristics of deep groundwater in the Linhuan coal-mining district, Northern Anhui Province, China. In this study, we report information about the physicochemical parameters, major ions, and heavy metals of 17 groundwater samples that were collected from the coal-bearing aquifer. The results show that the concentrations of total dissolved solids, electrical conductivity, and potassium and sodium (K(+) + Na(+)) in most of the groundwater samples exceeded the guidelines of the World Health Organization (WHO) and the Chinese National Standards for Drinking Water Quality (GB 5749-2006). The groundwater from the coal-bearing aquifer was dominated by the HCO3·Cl-K + Na and HCO3·SO4-K + Na types. Analysis with a Gibbs plot suggested that the major ion chemistry of the groundwater was primarily controlled by weathering of rocks and that the coal-bearing aquifer in the Linhuan coal-mining district was a relatively closed system. K(+) and Na(+) originated from halite and silicate weathering reactions, while Ca(2+) and Mg(2+) originated from the dissolution of calcite, dolomite, and gypsum or anhydrite. Ion exchange reactions also had an influence on the formation of major ions in groundwater. The concentrations of selected heavy metals decreased in the order Mn > Zn > Cr > Cu > Ni > Pb. In general, the heavy metal concentrations were low; however, the Cr, Mn, and Ni concentrations in some of the groundwater samples exceeded the standards outlined by the WHO, the GB 5749-2006, and the Chinese National Standards for Groundwater (GB/T 14848-93). Analysis by various indices (% Na, SAR, and EC), a USSL diagram, and a Wilcox diagram showed that both the salinity and alkalinity of the groundwater were high, such that the groundwater could not be used for irrigating agricultural land without treatment. These results will be significant for water resource exploiting and utilization in coal mine area.

Kinetics and mechanism of natural fluorapatite dissolution at 25 °C and pH from 3 to 12

NASA Astrophysics Data System (ADS)

Chaïrat, Claire; Schott, Jacques; Oelkers, Eric H.; Lartigue, Jean-Eric; Harouiya, Najatte

2007-12-01

The dissolution rates of natural fluorapatite (FAP), Ca 10(PO 4) 6F 2, were measured at 25 °C in mixed-flow reactors as a function of pH from 3.0 to 11.7, and aqueous calcium, phosphorus, and fluoride concentration. After an initial preferential Ca and/or F release, stoichiometric Ca, P, and F release was observed. Measured FAP dissolution rates decrease with increasing pH at 3 ⩽ pH ⩽ 7, FAP dissolution rates are pH independent at 7 ⩽ pH ⩽ 10, and FAP dissolution rates again decrease with increasing pH at pH ⩾ 10. Measured FAP dissolution rates are independent of aqueous Ca, P, and F concentration at pH ≈ 3 and pH ≈ 10. Apatite dissolution appears to be initiated by the relatively rapid removal from the near surface of F and the Ca located in the M1 sites, via proton for Ca exchange reactions. Dissolution rates are controlled by the destruction of this F and Ca depleted surface layer. The destruction of this layer is facilitated by the adsorption/penetration of protons into the surface at acidic conditions, and by surface hydration at neutral and basic conditions. Taking into account these two parallel mechanisms, measured fluorapatite forward dissolution rates can be accurately described using r+(molms)=6.61×10-6{aK}/{1+aK+aCa4aF1.4aOH0.6aH6K}+3.69×10-8[tbnd CaOH2+] where ai refers to the activity of the ith aqueous species, [tbnd CaOH2+] denotes the concentration of hydrated calcium sites at the surface of the leached layer (mol m -2), and Kex and Kads stand for the apparent stability constants of the Ca 2+/H + exchange and adsorption/penetration reactions, respectively.

Coal-water slurry spray characteristics of an electronically-controlled accumulator fuel injection system

NASA Astrophysics Data System (ADS)

Caton, J. A.; Payne, S. E.; Terracina, D. P.; Kihm, K. D.

Experiments have been complete to characterize coal-water slurry sprays from a electronically-controlled accumulator fuel injection system of diesel engine. The sprays were injected into a pressurized chamber equipped with windows. High speed movies, fuel pressures and needle lifts were obtained as a function of time, orifice diameter, coal loading, gas density in the chamber, and accumulator fuel pressure. For the base conditions 50% (by mass) coal loading, 0.4 mm diameter nozzle hole, coal-water slurry pressure of 82 MPa (12,000 psi), and a chamber density of 25 kg/m(exp 3), the break-up time was 0.30 ms. An empirical correlation for both spray tip penetration and initial jet velocity was developed. For the conditions of this study, the spray tip penetration and initial jet velocity were 15% greater for coal-water slurry than for diesel fuel or water. Cone angles of the sprays were dependent on the operating conditions and fluid, as well as the time and locations of the measurement. The time-averaged cone angle for the base case conditions was 13.6 degrees. Results of this study and the correlation are specific to the tested coal-water slurry and are not general for other coal-water slurry fuels.

Heat transfer capacity of heat pipes: An application in coalfield wildfire in China

NASA Astrophysics Data System (ADS)

Li, Bei; Deng, Jun; Xiao, Yang; Zhai, Xiaowei; Shu, Chi-Min; Gao, Wei

2018-01-01

Coalfield wildfires are serious catastrophes associated with mining activities. Generally, the coal wildfire areas have tremendous heat accumulation regions. Eliminating the internal heat is an effective method for coal wildfire control. In this study, high thermal conductivity component of a heat pipe (HP) was used for enhancing the heat dissipation efficiency and impeding heat accumulation. An experimental system was set up to analyze the thermal resistance network of the coal-HP system. A coal-HP heat removal model was also established for studying the heat transfer performance of HP on the coal pile. The HP exhibited outstanding cooling performance in the initial period, resulting in the highest temperature difference between the coal pile and ambient temperature. However, the effect of the HP on the distribution temperature of coal piles decreased with increasing distance. The largest decline in the coal temperature occurred in a 20-mm radius of the HP; the temperature decreased from 84.3 to 50.9 °C, a decline of 39.6%. The amount of energy transfer by the HP after 80 h was 1.0865, 2.1680, and 3.3649 MJ under the initial heat source temperatures of 100, 150, and 200 °C, respectively. The coal was governed below 80 °C with the HP under the experimental conditions. It revealed that the HP had a substantial effect on thermal removal and inhibited spontaneous coal combustion. In addition, this paper puts forward the technological path of HP to control typical coalfield wildfire.

Development of a 5 kW Prototype Coal-Based Fuel Cell

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chuang, Steven S.C.; Mirzababaei, Jelvehnaz; Rismanchian, Azadeh

2014-01-20

The University of Akron Fuel Cell Laboratory pioneered the development of a laboratory scale coal-based fuel cell, which allows the direct use of high sulfur content coal as fuel. The initial research and coal fuel cell technology development (“Coal-based Fuel Cell,” S. S. C. Chuang, PCT Int. Appl. 2006, i.e., European Patent Application, 35 pp. CODEN: PIXXD2 WO 2006028502 A2 20060316) have demonstrated that it is feasible to electrochemically oxidize carbon to CO2, producing electricity. The key innovative concept of this coal-based fuel cell technology is that carbon in coal can be converted through an electrochemical oxidation reaction into manageablemore » carbon dioxide, efficiently generating electricity without involving coal gasification, reforming, and water-gas shift reaction. This study has demonstrated that electrochemical oxidation of carbon can take place on the Ni anode surface and the CO and CO 2 product produced can further react with carbon to initiate the secondary reaction. A carbon injection system was developed to inject the solid fuel without bringing air into the anode chamber; a fuel cell stack was developed and tested to demonstrate the feasibility of the fuel cell stack. Further improvement of anode catalyst activity and durability is needed to bring this novel coal fuel cell to a highly efficient, super clean, multi-use electric generation technology, which promises to provide low cost electricity by expanding the utilization of U.S. coal supplies and relieving our dependence on foreign oil.« less

Cognitive processing in the aftermath of relationship dissolution: Associations with concurrent and prospective distress and posttraumatic growth.

PubMed

Del Palacio-González, Adriana; Clark, David A; O'Sullivan, Lucia F

2017-12-01

Non-marital romantic relationship dissolution is amongst the most stressful life events experienced by young adults. Yet, some individuals experience posttraumatic growth following relationship dissolution. Little is known about the specific and differential contribution of trait-like and event-specific cognitive processing styles to each of these outcomes. A longitudinal design was employed in which trait-like (brooding and reflection) and dissolution-specific (intrusive and deliberate) cognitive processing was examined as predictors of growth (Posttraumatic Growth Inventory) and distress (Breakup Distress Scale) following a recent relationship dissolution. Initially, 148 participants completed measures of trait-like and dissolution-specific cognitive processing, growth, and distress (T1). A subsample completed a seven-month follow-up (T2). Higher frequency of relationship-dissolution intrusive thoughts predicted concurrent distress after accounting for brooding and relationship characteristics. Further, higher brooding and lower reflection predicted higher distress prospectively. Concurrent growth was predicted by both higher brooding and more deliberate relationship-dissolution thoughts. Prospectively, T1 dissolution intrusive thoughts predicted higher T2 deliberate thoughts, and the interaction between these two constructs predicted higher T2 growth. Therefore, deliberately thinking of the dissolution was related to positive psychological outcomes. In contrast, intrusive dissolution cognitions and a tendency for brooding had a mixed (paradoxical) association with psychological adjustment. Copyright © 2016 John Wiley & Sons, Ltd.

Ionic liquid processing of cellulose.

PubMed

Wang, Hui; Gurau, Gabriela; Rogers, Robin D

2012-02-21

Utilization of natural polymers has attracted increasing attention because of the consumption and over-exploitation of non-renewable resources, such as coal and oil. The development of green processing of cellulose, the most abundant biorenewable material on Earth, is urgent from the viewpoints of both sustainability and environmental protection. The discovery of the dissolution of cellulose in ionic liquids (ILs, salts which melt below 100 °C) provides new opportunities for the processing of this biopolymer, however, many fundamental and practical questions need to be answered in order to determine if this will ultimately be a green or sustainable strategy. In this critical review, the open fundamental questions regarding the interactions of cellulose with both the IL cations and anions in the dissolution process are discussed. Investigations have shown that the interactions between the anion and cellulose play an important role in the solvation of cellulose, however, opinions on the role of the cation are conflicting. Some researchers have concluded that the cations are hydrogen bonding to this biopolymer, while others suggest they are not. Our review of the available data has led us to urge the use of more chemical units of solubility, such as 'g cellulose per mole of IL' or 'mol IL per mol hydroxyl in cellulose' to provide more consistency in data reporting and more insight into the dissolution mechanism. This review will also assess the greenness and sustainability of IL processing of biomass, where it would seem that the choices of cation and anion are critical not only to the science of the dissolution, but to the ultimate 'greenness' of any process (142 references).

Characterization of pH-fractionated humic acids derived from Chinese weathered coal.

PubMed

Zhang, Shuiqin; Yuan, Liang; Li, Wei; Lin, Zhian; Li, Yanting; Hu, Shuwen; Zhao, Bingqiang

2017-01-01

To reduce the compositional and structural heterogeneity of humic acids (HAs) and achieve better use of HA resources, in this study, we report a new sequential dissolution method for HAs derived from Chinese weathered coal. This method was used to separate HAs into seven fractions by adjusting the pH (3-10) of the extraction solution. The results showed that the HA fractions derived from Chinese weathered coal were concentrated up to 90.31% in the lower pH solutions (3-7). The compositional and structural characteristics of the HA fractions were determined by elemental analysis; ultraviolet-visible (UV-Vis), Fourier transform infrared (FTIR), and solid-state 13 C-nuclear magnetic resonance (NMR) spectroscopies; and other techniques. The results showed significant differences among the HA fractions. The concentrations of the total acidic groups and the carboxyl groups decreased with the increasing pH of the extraction solution. However, the HA fractions derived from extraction solutions with pH 3-4 had relatively lower aromaticity but a higher protonated carbon content. The HA fractions derived from extraction solutions with pH 6-7 had the highest aromaticity and the greatest abundance of COO/N-C=O. This study demonstrated that adjusting the pH of the extraction solution is one way to fractionate HAs from Chinese weathered coal and to obtain HA fractions with compositions and structures that could serve as useful material for study and utilization. Copyright © 2016 Elsevier Ltd. All rights reserved.

Clustered Single Cellulosic Fiber Dissolution Kinetics and Mechanisms through Optical Microscopy under Limited Dissolving Conditions.

PubMed

Mäkelä, Valtteri; Wahlström, Ronny; Holopainen-Mantila, Ulla; Kilpeläinen, Ilkka; King, Alistair W T

2018-05-14

Herein, we describe a new method of assessing the kinetics of dissolution of single fibers by dissolution under limited dissolving conditions. The dissolution is followed by optical microscopy under limited dissolving conditions. Videos of the dissolution were processed in ImageJ to yield kinetics for dissolution, based on the disappearance of pixels associated with intact fibers. Data processing was performed using the Python language, utilizing available scientific libraries. The methods of processing the data include clustering of the single fiber data, identifying clusters associated with different fiber types, producing average dissolution traces and also extraction of practical parameters, such as, time taken to dissolve 25, 50, 75, 95, and 99.5% of the clustered fibers. In addition to these simple parameters, exponential fitting was also performed yielding rate constants for fiber dissolution. Fits for sample and cluster averages were variable, although demonstrating first-order kinetics for dissolution overall. To illustrate this process, two reference pulps (a bleached softwood kraft pulp and a bleached hardwood pre-hydrolysis kraft pulp) and their cellulase-treated versions were analyzed. As expected, differences in the kinetics and dissolution mechanisms between these samples were observed. Our initial interpretations are presented, based on the combined mechanistic observations and single fiber dissolution kinetics for these different samples. While the dissolution mechanisms observed were similar to those published previously, the more direct link of mechanistic information with the kinetics improve our understanding of cell wall structure and pre-treatments, toward improved processability.

Analytical modeling of mercury injection in high-rank coalbed methane reservoirs based on pores and microfractures: a case study of the upper carboniferous Taiyuan Formation in the Heshun block of the Qinshui Basin, central China

NASA Astrophysics Data System (ADS)

Gu, Yang; Ding, Wenlong; Yin, Shuai; Wang, Ruyue; Mei, Yonggui; Liu, Jianjun

2017-03-01

The coalbed gas reservoirs in the Qinshui Basin in central China are highly heterogeneous; thus, the reservoir characteristics are difficult to assess. Research on the pore structure of a reservoir can provide a basis for understanding the occurrence and seepage mechanisms of coal reservoirs, rock physics modeling and the formulation of rational development plans. Therefore, the pore structure characteristics of the coalbed gas reservoirs in the high rank bituminous coal in the No. 15 coal seam of the Carboniferous Taiyuan Group in the Heshun coalbed methane (CBM) blocks in the northeastern Qinshui Basin were analyzed based on pressure mercury and scanning electron microscopy data. The results showed that the effective porosity system of the coal reservoir was mainly composed of pores and microfractures and that the pore throat configuration of the coal reservoir was composed of pores and microthroats. A model was developed based on the porosity and microfractures of the high rank coal rock and the mercury injection and drainage curves. The mercury injection curve model and the coal permeability are well correlated and were more reliable for the analysis of coal and rock pore system connectivity than the mercury drainage curve model. Coal rocks with developed microfractures are highly permeable; the production levels are often high during the initial drainage stages, but they decrease rapidly. A significant portion of the natural gas remains in the strata and cannot be exploited; therefore, the ultimate recovery is rather low. Coal samples with underdeveloped microfractures have lower permeabilities. While the initial production levels are lower, the production cycle is longer, and the ultimate recovery is higher. Therefore, the initial production levels of coal reservoirs with poorly developed microfractures in some regions of China may be low. However, over the long term, due to their higher ultimate recoveries and longer production cycles, the total gas production levels will increase. This understanding can provide an important reference for developing appropriate CBM development plans.

Effects of solution chemistry on arsenic(V) removal by low-cost adsorbents.

PubMed

Wang, Yuru; Tsang, Daniel C W

2013-11-01

Natural and anthropogenic arsenic (As) contamination of water sources pose serious health concerns, especially for small communities in rural areas. This study assessed the applicability of three industrial byproducts (coal fly ash, lignite, and green waste compost) as the low-cost adsorbents for As(V) removal under various field-relevant conditions (dissolved oxygen, As(V)/Fe ratio, solution pH, and presence of competing species). The physico-chemical properties of the adsorbents were characterized by XRD, XRF, FT-IR, and NMR analysis. Batch experiments demonstrated that coal fly ash could provide effective As(V) removal (82.1%-95%) because it contained high content of amorphous iron/aluminium hydroxides for As(V) adsorption and dissolvable calcium minerals for calcium arsenate precipitation. However, the addition of lignite and green waste compost was found unfavourable since they hindered the As(V) removal by 10%-42% possibly due to dissolution of organic matter and ternary arsenate-iron-organic matter complexes. On the other hand, higher concentrations of dissolved iron (comparing As(V)/Fe ratios of 1:1 and 1:10) and dissolved oxygen (comparing 0.2 and 6 mg/L) only marginally enhanced the As(V) removal at pH 6 and 8. Thus, addition of dissolved iron, water aeration, or pH adjustment became unnecessary because coal fly ash was able to provide effective As(V) removal under the natural range of geochemical conditions. Moreover, the presence of low levels of background competing (0.8 or 8 mg/L of humic acid, phosphate, and silicate) imposed little influence on As(V) removal, possibly because the high adsorption capacity of coal fly ash was far from exhaustion. These results suggested that coal fly ash was a potentially promising adsorbent that warranted further investigation.

Coal Combustion Science quarterly progress report, April--June 1992

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hardesty, D.R.; Hurt, R.H.; Baxter, L.L.

1992-09-01

The objective of this work is to support the Office of Fossil Energy in executing research on coal combustion science. This project consists of basic research on coal combustion that supports both the Pittsburgh Energy Technology Center (PETC) Direct Utilization Advanced Research and Technology Development Program, and the International Energy Agency (IEA) Coal Combustion Science Project. Specific tasks include: The characterization of the physical and chemical processes that constitute the early devolatilization phase of coal combustion: Characterization of the combustion behavior of selected coals under conditions relevant to industria pulverized coal-fired furnaces; and to establish a quantitative understanding of themore » mechanisms and rates of transformation, fragmentation, and deposition of mineral matter in coal combustion environments as a function of coal type, particle size and temperature, the initial forms and distributions of mineral species in the unreacted coal, and the local gas temperature and composition.« less

77 FR 39938 - Approval and Promulgation of Air Quality Implementation Plans; Maryland; Regional Haze State...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-07-06

... responses are provided below. Comment 1: The Commenter recommended that emission controls for a coal... Dakota. The Commenter stated that initially the coal cleaning facility was identified as BART-eligible... further evaluate controls at the coal cleaning facility and the three EGUs under the reasonable progress...

Coal Combustion Science quarterly progress report, April--June 1992. Task 1, Coal devolatilization: Task 2, Coal char combustion; Task 3, Fate of mineral matter

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hardesty, D.R.; Hurt, R.H.; Baxter, L.L.

1992-09-01

The objective of this work is to support the Office of Fossil Energy in executing research on coal combustion science. This project consists of basic research on coal combustion that supports both the Pittsburgh Energy Technology Center (PETC) Direct Utilization Advanced Research and Technology Development Program, and the International Energy Agency (IEA) Coal Combustion Science Project. Specific tasks include: The characterization of the physical and chemical processes that constitute the early devolatilization phase of coal combustion: Characterization of the combustion behavior of selected coals under conditions relevant to industria pulverized coal-fired furnaces; and to establish a quantitative understanding of themore » mechanisms and rates of transformation, fragmentation, and deposition of mineral matter in coal combustion environments as a function of coal type, particle size and temperature, the initial forms and distributions of mineral species in the unreacted coal, and the local gas temperature and composition.« less

Fossil Energy organization restructured

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

The Department of Energy has restructured its fossil energy organization to accommodate increases in activity and visibility of the President's $2.5 billion clean coal technology initiative. The realignment also includes changes in the coal research and development program and in supporting staff functions. In the coal program, changes in the organization include the establishment of two associate deputy assistant secretaries, both reporting to the deputy Assistant Secretary for Coal Technology. One associate deputy assistant secretary will oversee the Clean Coal Technology Program. A second associate deputy assistant secretary will manage the coal research and development program. An organizational chart illustratesmore » the new fossil energy headquarters organization.« less

Catalytic Graphitization of Coal-Based Carbon Materials with Light Rare Earth Elements.

PubMed

Wang, Rongyan; Lu, Guimin; Qiao, Wenming; Yu, Jianguo

2016-08-30

The catalytic graphitization mechanism of coal-based carbon materials with light rare earth elements was investigated using X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy, selected-area electron diffraction, and high-resolution transmission electron microscopy. The interface between light rare earth elements and carbon materials was carefully observed, and two routes of rare earth elements catalyzing the carbon materials were found: dissolution-precipitation and carbide formation-decomposition. These two simultaneous processes certainly accelerate the catalytic graphitization of carbon materials, and light rare earth elements exert significant influence on the microstructure and thermal conductivity of graphite. Moreover, by virtue of praseodymium (Pr), it was found that a highly crystallographic orientation of graphite was induced and formed, which was reasonably attributed to the similar arrangements of the planes perpendicular to (001) in both graphite and Pr crystals. The interface between Pr and carbon was found to be an important factor for the orientation of graphite structure.

The long-term dissolution characteristics of a residually trapped BTX mixture in soil

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rixey, W.G.

1996-12-31

A mass transfer limited model is presented to describe the long-term dissolution of organic compounds from a benzene, toluene, and xylenes (BTX) mixture residually trapped in a sandy soil. The model is an extension of a previously presented equilibrium dissolution model which takes into consideration mass transfer limitations that develop later in the leaching process and is similar to that presented by Borden and Kao for modeling BTX dissolution from residually trapped gasoline. The residual nonaqueous phase liquid (NAPL) is divided into multiple regions: one region which undergoes equilibrium dissolution and additional regions in which mass transfer is progressively limited.more » Application of the model to BTX column effluent data indicates that the initial dissolution (exponential decay region) of BTX can be effectively described by equilibrium dissolution. When applied to later dissolution times (Asymptotic region) a multiple-region model is required to rationalize the data for all three components. This explanation of the observed tailing in leaching experiments form residually trapped hydrocarbons if offered as an alternative to the explanation of tailing due to rate-limited desorption from soils. 16 refs., 5 figs., 2 tabs.« less

Dissolution patterns of biocompatible glasses in 2-amino-2-hydroxymethyl-propane-1,3-diol (Tris) buffer.

PubMed

Fagerlund, S; Hupa, L; Hupa, M

2013-02-01

A continuous flow measurement system with sensitive on-line ion analysis has been applied to study the initial dissolution behaviour of biocompatible glasses in Tris. Altogether 16 glasses with widely varying compositions were studied. The measurement system allowed for quantitative determination of the time-dependent rates of dissolution of sodium, potassium, calcium, magnesium, silicon and phosphorus during the first 10-15 min in contact with Tris solution. The dissolution rates of the different ions showed significant glass to glass variations, but all glasses studied showed one of four distinct dissolution patterns. The ion dissolution rates after an exposure of 1000 s, expressed as the normalized surface-specific mass loss rates, were compared with the in vitro and in vivo reactivity of the glasses as predicted by models in the literature. The results showed a clear correlation between the dissolution rates of the glasses in Tris and their reactivity as measured by other different methods. Consequently, the measured short-term dissolution patterns could be used to determine which glasses are suitable as bioactive, biodegradable, or inert biomaterials for medical devices. Copyright © 2012 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Significance of a Shelf-wide Dissolution Event during the Paleocene-Eocene Thermal Maximum, Maryland and New Jersey, USA

NASA Astrophysics Data System (ADS)

Bralower, T. J.; Kump, L. R.; Robinson, M. M.; Self-Trail, J. M.; Zachos, J. C.

2016-12-01

Continental-shelf sediments of the US Atlantic margin experienced a brief episode of carbonate dissolution during the onset of the Paleocene-Eocene Thermal Maximum (PETM). Dissolution is represented by reduced percentages of carbonate, and calcareous microfossil distribution and preservation trends, in cores from Maryland and New Jersey. The base and the top of the dissolution zone are abrupt compared to the gradual nature of the onset of the carbon isotope excursion (CIE). The thickness of the dissolution zone varies from 9 cm in the Bass River core (outer paleoshelf) to 1.6 m in the CamDor core (middle paleoshelf). The decrease in %CaCO3 suggests dissolution locally removed 83 to 100% of the initial biogenic carbonate. Shelf-wide dissolution during the onset of the PETM may be a regional event, associated, for example, with eutrophication. Samples from across the paleoshelf contain abundant fine-grained framboidal pyrite, which suggests photic-zone euxinia occurred before, during, and after the dissolution event. Dissolution may also be associated with oxidation of this pyrite during later exposure to oxidizing groundwaters, although the restricted duration of the dissolution interval argues against this. Alternatively, the dissolution event may have global significance related to surface ocean-water acidification or shoaling of the calcite compensation depth (CCD) to shelf depths. The event began near the onset of the CIE on the shelf, whereas dissolution in deep-sea sections began later. Earlier shelf dissolution is consistent with surface ocean acidification while later deep-sea dissolution is thought to be associated with shoaling of the CCD. In our presentation, we weigh evidence for each of these possibilities and test them using the global dataset.

Synthetic coprecipitates of exopolysaccharides and ferrihydrite. Part II: Siderophore-promoted dissolution

NASA Astrophysics Data System (ADS)

Mikutta, Christian; Kretzschmar, Ruben

2008-02-01

Ferrihydrite (Fh) coprecipitated with exopolymers of plants and microbes may differ in its geochemical reactivity from its abiotic counterpart. We synthesized Fh in the presence and absence of acid polysaccharides (polygalacturonic acid (PGA), alginate, xanthan) and characterized the physical and structural properties of the precipitates formed [Mikutta C., Mikutta R., Bonneville S., Wagner F., Voegelin A., Christl I. and Kretzschmar R. (2008) Synthetic coprecipitates of exopolysaccharides and ferrihydrite. Part I: Characterization. Geochim. Cosmochim. Acta]. In this paper, we focus on the reactivity of PGA and alginate coprecipitates and pure Fh, and studied their interaction with the microbial siderophore desferrioxamine B (DFOB) in the presence and absence of low molecular weight organic (LMWO) acid anions (malate, citrate). Batch adsorption and dissolution experiments were performed in the dark at pH 7 in 10 mM NaClO 4 background electrolyte. In the dissolution experiments, different modes of ligand addition were applied (single, simultaneous, stepwise). With an estimated Langmuir sorption maximum of 15 mmol/mol Fe, a PGA coprecipitate with 11% C org sorbed about four times as much DFOB as pure Fh, and the amount of DFOB sorbed was ˜4-fold larger than estimated from the sum of DFOB sorption to pure Fh and PGA alone. The apparent initial dissolution rates, Rapp-initial, and pseudo-first order rate coefficients, k, of the coprecipitates exceeded those of pure Fh by up to two orders of magnitude. Citrate and malate exerted a strong synergistic effect on the DFOB-promoted dissolution of pure Fh, whereas synergistic effects of both anions were absent or negligible for the coprecipitates. Rapp-initial of the citrate and DFOB-promoted dissolution of PGA coprecipitates increased with increasing molar C/Fe ratio of the coprecipitates, independent of the charge of the LMWO ligand. Our results indicate that polyuronates stabilize Fh particles sterically and /or electrostatically, thus increasing the mineral surface area accessible to LMWO ligands. In contrast, pure Fh was coagulated at pH 7 (pH iep of Fh = 7.1), and hence only a small fraction of the Fh surface underwent dissolution. The increase in ligand-accessible surface area of Fh upon coprecipitation with acid polysaccharides seems to primarily control the kinetics of the ligand-promoted dissolution at neutral pH. In pH environments where the solubility of Fe(III) is very low, dissolution rates of Fe(III) (hydr)oxides in such coprecipitates may therefore exceed those of pure minerals by several orders of magnitude, despite a similar crystallinity of the minerals.

High temperature alkali corrosion of ceramics in coal gas

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pickrell, G.R.; Sun, T.; Brown, J.J.

1992-02-24

The high temperature alkali corrosion kinetics of SiC have been systematically investigated from 950 to 1100[degrees]C at 0.63 vol % alkali vapor concentration. The corrosion rate in the presence of alkaliis approximately 10[sup 4] to 10[sup 5] times faster than the oxidation rate of SiC in air. The activation energy associated with the alkali corrosion is 406 kJ/mol, indicating a highly temperature-dependent reaction rate. The rate-controlling step of the overall reaction is likely to be the dissolution of silica in the sodium silicate liquid, based on the oxygen diffusivity data.

Heat transfer capacity of heat pipes: An application in coalfield wildfire in China

NASA Astrophysics Data System (ADS)

Li, Bei; Deng, Jun; Xiao, Yang; Zhai, Xiaowei; Shu, Chi-Min; Gao, Wei

2018-06-01

Coalfield wildfires are serious catastrophes associated with mining activities. Generally, the coal wildfire areas have tremendous heat accumulation regions. Eliminating the internal heat is an effective method for coal wildfire control. In this study, high thermal conductivity component of a heat pipe (HP) was used for enhancing the heat dissipation efficiency and impeding heat accumulation. An experimental system was set up to analyze the thermal resistance network of the coal-HP system. A coal-HP heat removal model was also established for studying the heat transfer performance of HP on the coal pile. The HP exhibited outstanding cooling performance in the initial period, resulting in the highest temperature difference between the coal pile and ambient temperature. However, the effect of the HP on the distribution temperature of coal piles decreased with increasing distance. The largest decline in the coal temperature occurred in a 20-mm radius of the HP; the temperature decreased from 84.3 to 50.9 °C, a decline of 39.6%. The amount of energy transfer by the HP after 80 h was 1.0865, 2.1680, and 3.3649 MJ under the initial heat source temperatures of 100, 150, and 200 °C, respectively. The coal was governed below 80 °C with the HP under the experimental conditions. It revealed that the HP had a substantial effect on thermal removal and inhibited spontaneous coal combustion. In addition, this paper puts forward the technological path of HP to control typical coalfield wildfire. [Figure not available: see fulltext.

Coal resource assessments using coal availability and recoverability methods

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rohrbacher, T.J.

1997-12-01

The U.S. Geological Survey (USGS), in conjunction with state geological surveys and other federal agencies, has initiated a study and developed methodology to reassess the nation`s major coal resources. This study differs from previous coal resource assessments of the USGS, U.S. Bureau of Mines, and the Department of Energy`s Energy Information Administration, because this program: (1) Identifies and characterizes the coal beds and coal zones that will provide the bulk of the nation`s coal-derived energy during the first quarter of the twenty-first century; (2) organizes geologic, chemical, environmental, and geographic information in digital format and makes these data available tomore » the public through the Internet or other digital media, such as CD ROMs; (3) includes coal resource availability and coal recoverability analyses for selected areas; (4) provides economic assessments and coal recoverability analyses for selected areas; (5) provides methodology to perform socio-economic impact analysis related to coal mining in specific geographical areas as small as a county.« less

Dissolution of Fe(III) (hydr) oxides by metal-EDTA complexes

NASA Astrophysics Data System (ADS)

Ngwack, Bernd; Sigg, Laura

1997-03-01

The dissolution of Fe(III)(hydr)oxides (goethite and hydrous ferric oxide) by metal-EDTA complexes occurs by ligand-promoted dissolution. The process is initiated by the adsorption of metal-EDTA complexes to the surface and is followed by the dissociation of the complex at the surface and the release of Fe(III)EDTA into solution. The dissolution rate is decreased to a great extent if EDTA is complexed by metals in comparison to the uncomplexed EDTA. The rate decreases in the order EDTA CaEDTA ≫ PbEDTA > ZnEDTA > CuEDTA > Co(II)EDTA > NiEDTA. Two different rate-limiting steps determine the dissolution process: (1) detachment of Fe(III) from the oxide-structure and (2) dissociation of the metal-EDTA complexes. In the case of goethite, step 1 is slower than step 2 and the dissolution rates by various metals are similar. In the case of hydrous ferric oxide, step 2 is rate-limiting and the effect of the complexed metal is very pronounced.

Effect of Initial Iron Content in a Zinc Bath on the Dissolution Rate of Iron During a Hot Dip Galvanizing Process

NASA Astrophysics Data System (ADS)

Lee, Sang Myung; Lee, Suk Kyu; Paik, Doo-Jin; Park, Joo Hyun

2017-04-01

The mechanism of iron dissolution and the effect of initial Fe content in a Zn bath on the dissolution rate of iron were investigated using a finger rotating method (FRM). When the initial iron content, [Fe]°, in the zinc bath was less than the solubility limit, the iron content in the zinc bath showed a rapid increase, whereas a moderate increase was observed when [Fe]° was close to the solubility limit. Based on Eisenberg's kinetic model, the mass transfer coefficient of iron in the present experimental condition was calculated to be k M = 1.2 × 10-5 m/s, which was similar to the results derived by Giorgi et al. under industrial practice conditions. A dissolution of iron occurred even when the initial iron content in the zinc bath was greater than the solubility limit, which was explained by the interfacial thermodynamics in conjunction with the morphology of the surface coating layer. By analyzing the diffraction patterns using TEM, the outermost dendritic-structured coating layer was confirmed as FeZn13 ( ζ). In order to satisfy the local equilibrium based on the Gibbs-Thomson equation, iron in the dendrite-structured phase spontaneously dissolved into the zinc bath, resulting in the enrichment of iron in front of the dendrite tip. Through the diffusion boundary layer in front of the dendritic-structured layer, dissolved Fe atoms diffused out and reacted with Zn and small amounts of Al, resulting in the formation of dross particles such as FeZn10Al x ( δ). It was experimentally confirmed that the smaller the difference between the initial iron content in the zinc bath and the iron solubility limit at a given temperature, the lower the number of formed dross particles.

U.S. Port Development and the Expanding World Coal Trade: A Study of Alternatives.

DTIC Science & Technology

1982-06-01

Dredging Program . . ... 70 4. Growth Potential Index . . . . . . . . . . 71 B. SENSITIVITY ANALYSIS . . . . . . . . . . .. . 74 1. Dredging Effect... PROGRAM TO ’:OMPUTE COST AND COAL CAPACITIES ............ .. 95 LIST OPREFRENCES .. . .. .. . . 999 INITIAL DISTRIBUTION LIST .... ....... .. 102 7 LIST...Deepuater Terminal Evaluation Summary ...... 64 Vi. Coal Export Capacities by Port ......... 68 VII. Optimal and Next Best Programs for Various

Alaska Regional Energy Resources Planning Project. Phase 2: coal, hydroelectric and energy alternatives. Volume I. Beluga Coal District Analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rutledge, G.; Lane, D.; Edblom, G.

This volume deals with the problems and procedures inherent in the development of the Beluga Coal District. Socio-economic implications of the development and management alternatives are discussed. A review of permits and approvals necessary for the initial development of Beluga Coal Field is presented. Major land tenure issues in the Beluga Coal District as well as existing transportation routes and proposed routes and sites are discussed. The various coal technologies which might be employed at Beluga are described. Transportation options and associated costs of transporting coal from the mine site area to a connecting point with a major, longer distancemore » transportation made and of transporting coal both within and outside (exportation) the state are discussed. Some environmental issues involved in the development of the Beluga Coal Field are presented. (DMC)« less

Coal-oil slurry preparation

DOEpatents

Tao, John C.

1983-01-01

A pumpable slurry of pulverized coal in a coal-derived hydrocarbon oil carrier which slurry is useful as a low-ash, low-sulfur clean fuel, is produced from a high sulfur-containing coal. The initial pulverized coal is separated by gravity differentiation into (1) a high density refuse fraction containing the major portion of non-coal mineral products and sulfur, (2) a lowest density fraction of low sulfur content and (3) a middlings fraction of intermediate sulfur and ash content. The refuse fraction (1) is gasified by partial combustion producing a crude gas product from which a hydrogen stream is separated for use in hydrogenative liquefaction of the middlings fraction (3). The lowest density fraction (2) is mixed with the liquefied coal product to provide the desired fuel slurry. Preferably there is also separately recovered from the coal liquefaction LPG and pipeline gas.

Method for increasing the calorific value of gas produced by the in situ combustion of coal

DOEpatents

Shuck, Lowell Z.

1978-01-01

The present invention relates to the production of relatively high Btu gas by the in situ combustion of subterranean coal. The coal bed is penetrated with a horizontally-extending borehole and combustion is initiated in the coal bed contiguous to the borehole. The absolute pressure within the resulting combustion zone is then regulated at a desired value near the pore pressure within the coal bed so that selected quantities of water naturally present in the coal will flow into the combustion zone to effect a hydrogen and carbon monoxide-producing steam-carbon reaction with the hot carbon in the combustion zone for increasing the calorific value of the product gas.

Improving the hardness of dry granulated tablets containing sodium lauryl sulfate.

PubMed

Moore, Francis; Okelo, Geoffrey; Colón, Ivelisse; Kushner, Joseph

2010-11-15

The impact of the addition of a wetting agent, the surfactant sodium lauryl sulfate (SLS), on the tablet hardness of a dry granulated, solid oral dosage form was investigated. In three batches, SLS was added concurrently with: (1) a poorly soluble, highly hydrophobic active pharmaceutical ingredient (API) and the other excipients prior to the initial blending step, (2) magnesium stearate prior to roller compaction, or (3) magnesium stearate prior to tableting. A fourth batch, which did not contain SLS, served as a control. The maximum hardness of 100 mg, 1/4″-SRC tablets for the four batches--SLS added initially, prior to roller compaction, prior to tableting, and no SLS--were 61±3, 71±3, 89±5, and 86±3N, respectively, suggesting reduced processing of SLS improves tablet hardness by ∼50%. Dissolution of the tablets in 900 ml of simulated gastric fluid with paddles at 75 rpm showed that: (1) there was no impact on the insertion point of SLS into the process on API dissolution, and (2) that the presence of SLS improved dissolution by 5% compared to the control tablets. Adding SLS just prior to tableting can improve tablet hardness and yield similar dissolution performance relative to SLS addition prior to the initial blending step. Copyright © 2010 Elsevier B.V. All rights reserved.

The Navy Biofuel Initiative Under the Defense Production Act

DTIC Science & Technology

2012-06-22

Market for Biomass -Based Diesel Fuel in the Renewable Fuel Standard (RFS), by Brent D. Yacobucci, The Market for Biomass -Based Diesel Fuel in the...defense.17 During the 1970s, DOE directed a synthetic fuels program toward commercializing coal liquefaction, coal gasification , and oil shale... Biomass : Background and Policy, by Anthony Andrews and Jeffrey Logan. The Navy Biofuel Initiative Under the Defense Production Act Congressional

Surfactant studies for bench-scale operation

NASA Technical Reports Server (NTRS)

Hickey, Gregory S.; Sharma, Pramod K.

1992-01-01

A phase 2 study was initiated to investigate surfactant-assisted coal liquefaction, with the objective of quantifying the enhancement in liquid yields and product quality. This publication covers the first quarter of work. The major accomplishments were: the refurbishment of the high-pressure, high-temperature reactor autoclave, the completion of four coal liquefaction runs with Pittsburgh #8 coal, two each with and without sodium lignosulfonate surfactant, and the development of an analysis scheme for the product liquid filtrate and filter cake. Initial results at low reactor temperatures show that the addition of the surfactant produces an improvement in conversion yields and an increase in lighter boiling point fractions for the filtrate.

Reactivity of coal in direct hydrogenation processes: Technical progress report, March-May 1987

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baldwin, R.M.; Miller, R.L.

Research during the past quarter centered on continuation of two facets related to the study of coal reactivity in direct hydrogenation liquefaction processes. Five coals from the Argonne Premium coal collection were liquefied at three temperature levels in order to gather data for kinetic analysis purposes. Conversion of these coals to THF-, toluene-, and hexane-solubles was determined at temperatures of 425, 400, and 375 C, and nominal reaction times of 3, 5, 10, 15, and 40 minutes in the microautoclave batch reaction system. Preliminary mathematical modeling of the data using simple irreversible rate expressions and more complex formulations based onmore » a statistical distribution of activation energies was initiated in order to investigate the feasibility of utilizing activation energy as an additional reactivity screening factor. Use of complex models such as the Anthony-Howard formulation for purposes of activation energy determination from liquefaction data at one temperature level was further examined. Five of the 21 coals from the Penn State Premium coal sample bank were liquefied at the standard reactivity screening conditions, and the rate and extent of conversion to THF-, and toluene-, and hexane-solubles quantified. These data were added to the existing data base containing similar information for the prior coal suites from the Exxon and Argonne collections, and preliminary correlational efforts for reactivity vs. coal properties were initiated. Prior conclusions regarding the effect of rank on the rate and extent of conversion were qualitatively verified from the data collected. 1 ref., 13 figs., 2 tabs.« less

Reactivity of Nanoscale Zero-Valent Iron in Unbuffered Systems: Effect of pH and Fe(II) Dissolution.

PubMed

Bae, Sungjun; Hanna, Khalil

2015-09-01

While most published studies used buffers to maintain the pH, there is limited knowledge regarding the reactivity of nanoscale zerovalent iron (NZVI) in poorly buffered pH systems to date. In this work, the effect of pH and Fe(II) dissolution on the reactivity of NZVI was investigated during the reduction of 4-nitrophenol (4-NP) in unbuffered pH systems. The reduction rate increased exponentially with respect to the NZVI concentration, and the ratio of dissolved Fe(II)/initial NZVI was related proportionally to the initial pH values, suggesting that lower pH (6-7) with low NZVI loading may slow the 4-NP reduction through acceleration of the dissolution of NZVI particles. Additional experiments using buffered pH systems confirmed that high pH values (8-9) can preserve the NZVI particles against dissolution, thereby enhancing the reduction kinetics of 4-NP. Furthermore, reduction tests using ferrous ion in suspensions of magnetite and maghemite showed that surface-bound Fe(II) on oxide coatings can play an important role in enhancing 4-NP reduction by NZVI at pH 8. These unexpected results highlight the importance of pH and Fe(II) dissolution when NZVI technology is applied to poorly buffered systems, particularly at a low amount of NZVI (i.e., <0.075 g/L).

Improving Competitiveness of U.S. Coal Dialogue

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kokkinos, Angelos

The Improving Competitiveness of U.S. Coal Dialogue held in September 2017 explored a broad range of technical developments that have the potential to improve U.S. coal competitiveness in domestic and overseas markets. The workshop is one in a series of events hosted by DOE to gather expert input on challenges and opportunities for reviving the coal economy. This event brought together coal industry experts to review developments in a broad range of technical areas such as conventional physical (e.g. dense-medium) technologies, and dry coal treatments; thermal, chemical, and bio-oxidation coal upgrading technologies; coal blending; and applications for ultrafine coal andmore » waste streams. The workshop was organized to focus on three main discussion topics: Challenges and Opportunities for Improving U.S. Coal Competitiveness in Overseas Markets, Mineral Processing, and Technologies to Expand the Market Reach of Coal Products. In each session, invited experts delivered presentations to help frame the subsequent group discussion. Throughout the discussions, participants described many possible areas of research and development (R&D) in which DOE involvement could help to produce significant outcomes. In addition, participants discussed a number of open questions—those that the industry has raised or investigated but not yet resolved. In discussing the three topics, the participants suggested potential areas of research and issues for further investigation. As summarized in Table ES-1, these crosscutting suggestions centered on combustion technologies, coal quality, coal processing, environmental issues, and other issues. The discussions at this workshop will serve as an input that DOE considers in developing initiatives that can be pursued by government and industry. This workshop generated strategies that described core research concepts, identified implementation steps, estimated benefits, clarified roles of government and industry, and outlined next steps. While more work is needed, each of these initiatives, included in the sections that follow, details new ideas to increase efficiency and reduce carbon emissions. DOE will integrate the results of this workshop with ongoing research work at the National Laboratories as well as other relevant data sources. This combined information will be used to develop a comprehensive strategy for capitalizing on the opportunity for U.S. coal and mineral competitiveness.« less

Structurally Altered Hard Coal in the Areas of Tectonic Disturbances - An Initial Attempt at Classification

NASA Astrophysics Data System (ADS)

Godyń, Katarzyna

2016-09-01

As regards the exploitation of hard coal seams, the near-fault zones and faults themselves are considered to be particularly dangerous areas, which is due to a high probability of the occurrence of gasogeodynamic phenomena. Tectonic dislocations running across a seam have a destructive impact on coal. Degradation of the coal structure, particularly visible in the microscale, is reflected in the coal's strength or gas properties. Such "structurally altered" coal is characterized by the presence of numerous fracturings, crushed areas, or dislocations of some of its fragments, and sometimes even the total destruction of the original structure. The present paper provides a detailed analysis and description of near-fault coal obtained from selected seams of the Upper Silesian Coal Basin, completed due to the application of optical methods. Both the type and the degree of changes in the structure of such coal were identified. On this basis, the author attempted to systematize the nomenclature used in relation to selected Upper Silesian hard coal seams, which, in turn, resulted in a proposed classification of the "altered structures" of the near-fault coal.

Phyto-bioconversion of hard coal in the Cynodon dactylon/coal rhizosphere.

PubMed

Igbinigie, Eric E; Mutambanengwe, Cecil C Z; Rose, Peter D

2010-03-01

Fundamental processes involved in the microbial degradation of coal and its derivatives have been well documented. A mutualistic interaction between plant roots and certain microorganisms to aid growth of plants such as Cynodon dactylon (Bermuda grass) on hard coal dumps has recently been suggested. In the present study coal bioconversion activity of nonmycorrhizal fungi was investigated in the C. dactylon/coal rhizosphere. Fungal growth on 2% Duff-agar, gutation formation on nitric acid treated coal and submerged culture activity in nitrogen-rich and -deficient broth formed part of the screening and selection of the fungi. The selected fungal isolates were confirmed to be found in pristine C. dactylon/coal rhizosphere. To simulate bioconversion, a fungal aliquot of this rhizosphere was used as inoculum for a Perfusate fixed bed bioreactor, packed with coal. The results demonstrate an enhanced coal bioconversion facilitated by low molecular weight organics and the bioconversion of coal may be initiated by an introduction of nitrogen moieties to the coal substrate. These findings suggest a phyto-bioconversion of hard coal involving plant and microbes occurring in the rhizosphere to promote the growth of C. dactylon. An understanding of this relationship can serve as a benchmark for coal dumps rehabilitation as well as for the industrial scale bioprocessing of hard coal.

Results of Characterization and Retrieval Testing on Tank 241-C-109 Heel Solids

DOE Office of Scientific and Technical Information (OSTI.GOV)

Callaway, William S.

Eight samples of heel solids from tank 241-C-109 were delivered to the 222-S Laboratory for characterization and dissolution testing. After being drained thoroughly, one-half to two-thirds of the solids were off-white to tan solids that, visually, were fairly evenly graded in size from coarse silt (30-60 μm) to medium pebbles (8-16 mm). The remaining solids were mostly strongly cemented aggregates ranging from coarse pebbles (16-32 mm) to fine cobbles (6-15 cm) in size. Solid phase characterization and chemical analysis indicated that the air-dry heel solids contained ≈58 wt% gibbsite [Al(OH){sub 3}] and ≈37 wt% natrophosphate [Na{sub 7}F(PO{sub 4}){sub 2}·19H{sub 2}O].more » The strongly cemented aggregates were mostly fine-grained gibbsite cemented with additional gibbsite. Dissolution testing was performed on two test samples. One set of tests was performed on large pieces of aggregate solids removed from the heel solids samples. The other set of dissolution tests was performed on a composite sample prepared from well-drained, air-dry heel solids that were crushed to pass a 1/4-in. sieve. The bulk density of the composite sample was 2.04 g/mL. The dissolution tests included water dissolution followed by caustic dissolution testing. In each step of the three-step water dissolution tests, a volume of water approximately equal to 3 times the initial volume of the test solids was added. In each step, the test samples were gently but thoroughly mixed for approximately 2 days at an average ambient temperature of 25 °C. The caustic dissolution tests began with the addition of sufficient 49.6 wt% NaOH to the water dissolution residues to provide ≈3.1 moles of OH for each mole of Al estimated to have been present in the starting composite sample and ≈2.6 moles of OH for each mole of Al potentially present in the starting aggregate sample. Metathesis of gibbsite to sodium aluminate was then allowed to proceed over 10 days of gentle mixing of the test samples at temperatures ranging from 26-30 °C. The metathesized sodium aluminate was then dissolved by addition of volumes of water approximately equal to 1.3 times the volumes of caustic added to the test slurries. Aluminate dissolution was allowed to proceed for 2 days at ambient temperatures of ≈29 °C. Overall, the sequential water and caustic dissolution tests dissolved and removed 80.0 wt% of the tank 241-C-109 crushed heel solids composite test sample. The 20 wt% of solids remaining after the dissolution tests were 85-88 wt% gibbsite. If the density of the residual solids was approximately equal to that of gibbsite, they represented ≈17 vol% of the initial crushed solids composite test sample. In the water dissolution tests, addition of a volume of water ≈6.9 times the initial volume of the crushed solids composite was sufficient to dissolve and recover essentially all of the natrophosphate present. The ratio of the weight of water required to dissolve the natrophosphate solids to the estimated weight of natrophosphate present was 8.51. The Environmental Simulation Program (OLI Systems, Inc., Morris Plains, New Jersey) predicts that an 8.36 w/w ratio would be required to dissolve the estimated weight of natrophosphate present in the absence of other components of the heel solids. Only minor amounts of Al-bearing solids were removed from the composite solids in the water dissolution tests. The caustic metathesis/aluminate dissolution test sequence, executed at temperatures ranging from 27-30 °C, dissolved and recovered ≈69 wt% of the gibbsite estimated to have been present in the initial crushed heel solids composite. This level of gibbsite recovery is consistent with that measured in previous scoping tests on the dissolution of gibbsite in strong caustic solutions. Overall, the sequential water and caustic dissolution tests dissolved and removed 80.3 wt% of the tank 241-C-109 aggregate solids test sample. The residual solids were 92-95 wt% gibbsite. Only a minor portion (≈4.5 wt%) of the aggregate solids was dissolved and recovered in the water dissolution test. Other than some smoothing caused by continuous mixing, the aggregates were essentially unaffected by the water dissolution tests. During the caustic metathesis/aluminate dissolution test sequence, ≈81 wt% of the gibbsite estimated to have been present in the aggregate solids was dissolved and recovered. The pieces of aggregate were significantly reduced in size but persisted as distinct pieces of solids. The increased level of gibbsite recovery, as compared to that for the crushed heel solids composite, suggests that the way the gibbsite solids and caustic solution are mixed is a key determinant of the overall efficiency of gibbsite dissolution and recovery. The liquids recovered after the caustic dissolution tests on the crushed solids composite and the aggregate solids were observed for 170 days. No precipitation of gibbsite was observed. The distribution of particle sizes in the residual solids recovered following the dissolution tests on the crushed heel solids composite was characterized. Wet sieving indicated that 21.4 wt% of the residual solids were >710 μm in size, and laser light scattering indicated that the median equivalent spherical diameter in the <710-μm solids was 35 μm. The settling behavior of the residual solids following the large-scale dissolution tests was also studied. When dispersed at a concentration of ≈1 vol% in water, ≈24 wt% of the residual solids settled at a rate >0.43 in./s; ≈68 wt% settled at rates between 0.02 and 0.43 in./s; and ≈7 wt% settled slower than 0.02 in./s.« less

JPRS Report, Science & Technology, Japan

DTIC Science & Technology

1987-10-27

large untapped deposits of low-grade coal in such countries as Thailand and Indonesia . China has large shares of both the production and consumption...their supply and demand situations well balanced. Among these nations, production and consumption of coal are also well balanced, and there are...of coal in this region. Among other energy sources, natural gas is still in the initial stages of development and utilization, and hydropower

Glass composition and solution speciation effects on stage III dissolution

DOE Office of Scientific and Technical Information (OSTI.GOV)

Trivelpiece, Cory L.; Rice, Jarret A.; Pantano, Carlo G.

To understand and mitigate the onset of Stage III corrosion of multicomponent oxides waste glasses. Stage III refers to a resumption of the high initial rate of glass dissolution in some glass samples that have otherwise exhibited dissolution at the much lower residual rate for a long time (Stage II). Although the onset of Stage III is known to occur concurrently with the precipitation of particular alteration products, the root cause of the transition is still unknown. Certain glass compositions (notably AFCI) and high pH environmental conditions are also associated with this observed transition.

Coal ash by-product reutilization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Muncy, J.; Miller, B.

1997-09-01

Potomac Electric Power Company (PEPCO) has as part of its vision and value statement that, ``We are responsible stewards of environmental and corporate resources.`` With this moral imperative in mind, a project team was charged with initiating the Coal Pile Liner Project--installing a membrane liner under the existing coal storage pile at the Morgantown Generating Station. The existing coal yard facilities were constructed prior to the current environmental regulations, and it became necessary to upgrade the storage facilities to be environmentally friendly. The project team had two objectives in this project: (1) prevent coal pile leachate from entering the groundwatermore » system; (2) test the viability of using coal ash by-products as an aggregate substitute for concrete applications. Both objectives were met, and two additional benefits were achieved as well: (1) the use of coal ash by-products as a coal liner produced significant cost savings to the project directly; (2) the use of coal ash by-products reduced plant operation and maintenance expenses.« less

Bioconversion of Coal: Hydrologic indicators of the extent of coal biodegradation under different redox conditions and coal maturity, Velenje Basin case study, Slovenia

NASA Astrophysics Data System (ADS)

Kanduč, Tjaša; Grassa, Fausto; Lazar, Jerneja; Jamnikar, Sergej; Zavšek, Simon; McIntosh, Jennifer

2014-05-01

Underground mining of coal and coal combustion for energy has significant environmental impacts. In order to reduce greenhouse gas emissions, other lower -carbon energy sources must be utilized. Coalbed methane (CBM) is an important source of relatively low-carbon energy. Approximately 20% of world's coalbed methane is microbial in origin (Bates et al., 2011). Interest in microbial CBM has increased recently due to the possibility of stimulating methanogenesis. Despite increasing interest, the hydrogeochemical conditions and mechanisms for biodegradation of coal and microbial methane production are poorly understood. This project aims to examine geochemical characteristics of coalbed groundwater and coalbed gases in order to constrain biogeochemical processes to better understand the entire process of coal biodegradation of coal to coalbed gases. A better understanding of geochemical processes in CBM areas may potentially lead to sustainable stimulation of microbial methanogenesis at economical rates. Natural analogue studies of carbon dioxide occurring in the subsurface have the potential to yield insights into mechanisms of carbon dioxide storage over geological time scales (Li et al., 2013). In order to explore redox processes related to methanogenesis and determine ideal conditions under which microbial degradation of coal is likely to occur, this study utilizes groundwater and coalbed gas samples from Velenje Basin. Determination of the concentrations of methane, carbondioxide, nitrogen, oxygen, argon was performed with homemade NIER mass spectrometer. Isotopic composition of carbon dioxide, isotopic composition of methane, isotopic composition of deuterium in methane was determined with Europa-Scientific IRMS with an ANCA-TG preparation module and Thermo Delta XP GC-TC/CF-IRMS coupled to a TRACE GC analyzer. Total alkalinity of groundwater was measured by Gran titration. Major cations were analyzed by ICP-OES and anions by IC method. Isotopic composition of dissolved inorganic carbon was determined by MultiflowBio preparation module. The stable isotope composition of sulphur was determined with a Europa Scientific 20-20 continuous flow IRMS ANCA-SL preparation module. Concentrations of tritium were determined with the electrolytic enrichment method. PHREEQC for Windows was used to perform thermodynamic modelling. The average coalbed gas composition in the coalbed seam is approximately carbon dioxide: methane > 2:1, where a high proportion of CO2 is adsorbed on the lignite structure, while methane is present free in coal fractures. It can be concluded that isotopic composition of carbon in methane from -70.4‰ to -50.0‰ is generated via acetate fermentation and via reduction of carbon dioxide, while isotopic composition of carbon in methane values range from -50.0‰ to -18.8‰, thermogenic methane can be explained by secondary processes, causing enrichment of residual methane with the heavier carbon isotope. Isotopic composition of deuterium in methane range from -343.9‰ to -223.1‰. Isotopic composition of carbon in carbon dioxide values at excavation fields range from -11.0‰ to +5‰ and are endogenic and microbial in origin. The major ion chemistry, redox conditions, stable isotopes and tritium measured in groundwater from the Velenje Basin, suggest that the Pliocene and Triassic aquifers contain distinct water bodies. Groundwater in the Triassic aquifer is dominated by hydrogen carbonate, calcium, magnesium and isotopic composition of dissolved inorganic carbon indicating degradation of soil organic matter and dissolution of carbonate minerals, similar to surface waters. In addition, groundwater in the Triassic aquifer has isotopic composition of oxygen and isotopic composition of deuterium values which plot near surface waters on the local and global meteoric water lines and detectable tritium reflects recent recharge. In contrast, groundwater in the Pliocene aquifers is enriched in magnesium, sodium, calcium, potassium, and silica and has alkalinity and isotopic composition of dissolved inorganic carbon values with low sulphate and nitrate concentrations. These waters have likely been influenced by sulfate reduction and microbial methanogenesis associated with coal seams and dissolution of feldspars and magnesium-rich clay minerals. Pliocene aquifer waters are also depleted in heavier oxygen isotope and heavier deuterium isotope and have tritium concentrations near the detection limit, suggesting these waters are older. References Bates, B.L., McIntosh J.C., Lohse K.A., Brooks P.D. 2011: Influence of groundwater flowpaths, residence times, and nutrients on the extent of microbial methanogenesis in coal beds: Powder River Basin, USA, Chemical geology, 284, 45-61. Li, W., Cheng Y., Wang L., Zhou H., Wang H., Wang L. 2013: Evaluating the security of geological coalbed sequestration of supercritical CO2 reservoirs: The Haishiwan coalfield, China as a natural analogue, International Journal of Greenhouse Gas Control, 13, 102-111.

Insight into the Development of Dissolution Media for BCS Class II Drugs: A Review from Quality Control and Prediction of In Vivo Performance Perspectives.

PubMed

Wu, Chunnuan; Liu, Yan; He, Zhonggui; Sun, Jin

2016-01-01

To assess in vivo behavior through in vitro method, the dissolution test is mostly used, both for quality control (QC) and for development purpose. In view of the fact that a dissolution test can hardly achieve two goals at the same time, the design of dissolution testing generally varies along with the development stage of drug products and therefore the selection of dissolution media may change with the goals of the dissolution test. To serve the QC purpose, a dissolution medium is designed to provide a sink condition; for development purpose, the dissolution medium is required to simulate the physiological conditions in the gastrointestinal tract as far as possible. In this review, we intended to provide an initial introduction to the various dissolution media applied for QC and formulation development purposes for poorly water soluble drugs. We focused on these methods like addition of cosolvents, surfactants and utilization of biphasic media, applied to provide sink conditions which are difficult to be achieved by simple aqueous buffers for lipophilic drugs, and introduced the development of physiologically relevant media for human and animals like dog and rat with respect to the choice of buffers, bile salts, lipids and so on. In addition, we further discussed the influence of biorelevant dissolution media on the modification of drug Biopharmaceutical Classification System (BCS) classification, especially for BCS class II drugs with low solubility and high permeability, the solubility of which is relatively sensitive to the presence of bile salts and lipids.

Dissolution of cinnabar (HgS) in the presence of natural organic matter

USGS Publications Warehouse

Waples, J.S.; Nagy, K.L.; Aiken, G.R.; Ryan, J.N.

2005-01-01

Cinnabar (HgS) dissolution rates were measured in the presence of 12 different natural dissolved organic matter (DOM) isolates including humic, fulvic, and hydrophobic acid fractions. Initial dissolution rates varied by 1.3 orders of magnitude, from 2.31 ?? 10-13 to 7.16 ?? 10-12 mol Hg (mg C)-1 m-2 s-1. Rates correlate positively with three DOM characteristics: specific ultraviolet absorbance (R2 = 0.88), aromaticity (R2 = 0.80), and molecular weight (R2 = 0.76). Three experimental observations demonstrate that dissolution was controlled by the interaction of DOM with the cinnabar surface: (1) linear rates of Hg release with time, (2) significantly reduced rates when DOM was physically separated from the surface by dialysis membranes, and (3) rates that approached constant values at a specific ratio of DOM concentration to cinnabar surface area, suggesting a maximum surface coverage by dissolution-reactive DOM. Dissolution rates for the hydrophobic acid fractions correlate negatively with sorbed DOM concentrations, indicating the presence of a DOM component that reduced the surface area of cinnabar that can be dissolved. When two hydrophobic acid isolates that enhanced dissolution to different extents were mixed equally, a 20% reduction in rate occurred compared to the rate with the more dissolution-enhancing isolate alone. Rates in the presence of the more dissolution-enhancing isolate were reduced by as much as 60% when cinnabar was prereacted with the isolate that enhanced dissolution to a lesser extent. The data, taken together, imply that the property of DOM that enhances cinnabar dissolution is distinct from the property that causes it to sorb irreversibly to the cinnabar surface. Copyright ?? 2005 Elsevier Ltd.

Research on Improving Low Rank Coal Caking Ability by Moderate Hydrogenation

NASA Astrophysics Data System (ADS)

Huang, Peng

2017-12-01

The hydrogenation test of low metamorphic coal was carried out by using a continuous hydrogen reactor at the temperature of (350-400)°C and the initial hydrogen pressure of 3 ~ 6Mpa. The purpose of the experiment was to increase the caking property, and the heating time was controlled from 30 to 50min. The test results show that the mild hydrogenation test, no adhesion of low metamorphic coal can be transformed into a product having adhesion, oxygen elements in coal have good removal, the calorific value of the product has been improved significantly and coal particles during pyrolysis, swelling, catalyst, hydrogenation, structural changes and the combined effects of particles a new component formed between financial and is a major cause of coal caking enhancement and lithofacies change, coal blending test showed that the product can be used effectively in the coking industry.

Hydration of dicalcium silicate and diffusion through neo-formed calcium-silicate-hydrates at weathered surfaces control the long-term leaching behaviour of basic oxygen furnace (BOF) steelmaking slag.

PubMed

Stewart, Douglas I; Bray, Andrew W; Udoma, Gideon; Hobson, Andrew J; Mayes, William M; Rogerson, Mike; Burke, Ian T

2018-04-01

Alkalinity generation and toxic trace metal (such as vanadium) leaching from basic oxygen furnace (BOF) steel slag particles must be properly understood and managed by pre-conditioning if beneficial reuse of slag is to be maximised. Water leaching under aerated conditions was investigated using fresh BOF slag at three different particle sizes (0.5-1.0, 2-5 and 10 × 10 × 20 mm blocks) and a 6-month pre-weathered block. There were several distinct leaching stages observed over time associated with different phases controlling the solution chemistry: (1) free-lime (CaO) dissolution (days 0-2); (2) dicalcium silicate (Ca 2 SiO 4 ) dissolution (days 2-14) and (3) Ca-Si-H and CaCO 3 formation and subsequent dissolution (days 14-73). Experiments with the smallest size fraction resulted in the highest Ca, Si and V concentrations, highlighting the role of surface area in controlling initial leaching. After ~2 weeks, the solution Ca/Si ratio (0.7-0.9) evolved to equal those found within a Ca-Si-H phase that replaced dicalcium silicate and free-lime phases in a 30- to 150-μm altered surface region. V release was a two-stage process; initially, V was released by dicalcium silicate dissolution, but V also isomorphically substituted for Si into the neo-formed Ca-Si-H in the alteration zone. Therefore, on longer timescales, the release of V to solution was primarily controlled by considerably slower Ca-Si-H dissolution rates, which decreased the rate of V release by an order of magnitude. Overall, the results indicate that the BOF slag leaching mechanism evolves from a situation initially dominated by rapid hydration and dissolution of primary dicalcium silicate/free-lime phases, to a slow diffusion limited process controlled by the solubility of secondary Ca-Si-H and CaCO 3 phases that replace and cover more reactive primary slag phases at particle surfaces.

Surfactant studies for bench-scale operation

NASA Technical Reports Server (NTRS)

Hickey, Gregory S.; Sharma, Pramod K.

1993-01-01

A phase 2 study has been initiated to investigate surfactant-assisted coal liquefaction, with the objective of quantifying the enhancement in liquid yields and product quality. This report covers the second quarter of work. The major accomplishments were: completion of coal liquefaction autoclave reactor runs with Illinois number 6 coal at processing temperatures of 300, 325, and 350 C, and pressures of 1800 psig; analysis of the filter cake and the filtrate obtained from the treated slurry in each run; and correlation of the coal conversions and the liquid yield quality to the surfactant concentration. An increase in coal conversions and upgrading of the liquid product quality due to surfactant addition was observed for all runs.

Control of Drug Dissolution Rate from Film Dosage Forms Containing Valsartan.

PubMed

Murata, Yoshifumi; Kofuji, Kyoko; Maida, Chieko

2016-01-01

Film dosage forms (FDs) containing valsartan (VST), a popular antihypertensive drug, were prepared using a casting method with sodium alginate and other polysaccharides as the film base. Drug dissolution profiles of the FDs were investigated in limited medium. The FDs were 170-200 μm thick and were easy to handle. All FDs immediately swelled and disintegrated in the medium. About 23% of the VST incorporated into the FD prepared with 1.5% sodium alginate dissolved at 5 min. The initial dissolution rate of VST increased upon the addition of chitosan to the film base; this effect was not observed in the case of chitin. On the other hand, the rate apparently decreased upon modification with alginic acid. In addition, the solubility of VST in the dissolution medium was changed by the addition of chitosan or alginic acid. FDs prepared with polysaccharides are useful for simplifying the administration of drugs to patients, and the drug dissolution rate from FDs can be controlled by modification.

Real-Time X-ray Imaging Reveals Interfacial Growth, Suppression, and Dissolution of Zinc Dendrites Dependent on Anions of Ionic Liquid Additives for Rechargeable Battery Applications.

PubMed

Song, Yuexian; Hu, Jiugang; Tang, Jia; Gu, Wanmiao; He, Lili; Ji, Xiaobo

2016-11-23

The dynamic interfacial growth, suppression, and dissolution of zinc dendrites have been studied with the imidazolium ionic liquids (ILs) as additives on the basis of in situ synchrotron radiation X-ray imaging. The phase contrast difference of real-time images indicates that zinc dendrites are preferentially developed on the substrate surface in the ammoniacal electrolytes. After adding imidazolium ILs, both nucleation overpotential and polarization extent increase in the order of additive-free < EMI-Cl < EMI-PF 6 < EMI-TFSA < EMI-DCA. The real-time X-ray images show that the EMI-Cl can suppress zinc dendrites, but result in the formation of the loose deposits. The EMI-PF 6 and EMI-TFSA additives can smooth the deposit morphology through suppressing the initiation and growth of dendritic zinc. The addition of EMI-DCA increases the number of dendrite initiation sites, whereas it decreases the growth rate of dendrites. Furthermore, the dissolution behaviors of zinc deposits are compared. The zinc dendrites show a slow dissolution process in the additive-free electrolyte, whereas zinc deposits are easily detached from the substrate in the presence of EMI-Cl, EMI-PF 6 , or EMI-TFSA due to the formation of the loose structure. Hence, the dependence of zinc dendrites on anions of imidazolium IL additives during both electrodeposition and dissolution processes has been elucidated. These results could provide the valuable information in perfecting the performance of zinc-based rechargeable batteries.

Lattice Boltzmann simulation of dissolution-induced changes in permeability and porosity in 3D CO2 reactive transport

NASA Astrophysics Data System (ADS)

Tian, Zhiwei; Wang, Junye

2018-02-01

Dissolution and precipitation of rock matrix are one of the most important processes of geological CO2 sequestration in reservoirs. They change connections of pore channels and properties of matrix, such as bulk density, microporosity and hydraulic conductivity. This study builds on a recently developed multi-layer model to account for dynamic changes of microporous matrix that can accurately predict variations in hydraulic properties and reaction rates due to dynamic changes in matrix porosity and pore connectivity. We apply the model to simulate the dissolution and precipitation processes of rock matrix in heterogeneous porous media to quantify (1) the effect of the reaction rate on dissolution and matrix porosity, (2) the effect of microporous matrix diffusion on the overall effective diffusion and (3) the effect of heterogeneity on hydraulic conductivity. The results show the CO2 storage influenced by factors including the matrix porosity change, reaction front movement, velocity and initial properties. We also simulated dissolution-induced permeability enhancement as well as effects of initial porosity heterogeneity. The matrix with very low permeability, which can be unresolved on X-ray CT, do contribute to flow patterns and dispersion. The concentration of reactant H+ increases along the main fracture paths where the flow velocity increases. The product Ca++ shows the inversed distribution pattern against the H+ concentration. This demonstrates the capability of this model to investigate the complex CO2 reactive transport in real 3D heterogeneous porous media.

Free radical reaction characteristics of coal low-temperature oxidation and its inhibition method.

PubMed

Li, Zenghua; Kong, Biao; Wei, Aizhu; Yang, Yongliang; Zhou, Yinbo; Zhang, Lanzhun

2016-12-01

Study on the mechanism of coal spontaneous combustion is significant for controlling fire disasters due to coal spontaneous combustion. The free radical reactions can explain the chemical process of coal at low-temperature oxidation. Electron spin resonance (ESR) spectroscopy was used to measure the change rules of the different sorts and different granularity of coal directly; ESR spectroscopy chart of free radicals following the changes of temperatures was compared by the coal samples applying air and blowing nitrogen, original coal samples, dry coal samples, and demineralized coal samples. The fragmentation process was the key factor of producing and initiating free radical reactions. Oxygen, moisture, and mineral accelerated the free radical reactions. Combination of the free radical reaction mechanism, the mechanical fragmentation leaded to the elevated CO concentration, fracturing of coal pillar was more prone to spontaneous combustion, and spontaneous combustion in goaf accounted for a large proportion of the fire in the mine were explained. The method of added diphenylamine can inhibit the self-oxidation of coal effectively, the action mechanism of diphenylamine was analyzed by free radical chain reaction, and this research can offer new method for the development of new flame retardant.

Continuous bench-scale slurry catalyst testing direct coal liquefaction rawhide sub-bituminous coal

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bauman, R.F.; Coless, L.A.; Davis, S.M.

In 1992, the Department of Energy (DOE) sponsored research to demonstrate a dispersed catalyst system using a combination of molybdenum and iron precursors for direct coal liquefaction. This dispersed catalyst system was successfully demonstrated using Black Thunder sub-bituminous coal at Wilsonville, Alabama by Southern Electric International, Inc. The DOE sponsored research continues at Exxon Research and Development Laboratories (ERDL). A six month continuous bench-scale program using ERDL`s Recycle Coal Liquefaction Unit (RCLU) is planned, three months in 1994 and three months in 1995. The initial conditions in RCLU reflect experience gained from the Wilsonville facility in their Test Run 263.more » Rawhide sub-bituminous coal which is similar to the Black Thunder coal tested at Wilsonville was used as the feed coal. A slate of five dispersed catalysts for direct coal liquefaction of Rawhide sub-bituminous coal has been tested. Throughout the experiments, the molybdenum addition rate was held constant at 100 wppm while the iron oxide addition rate was varied from 0.25 to 1.0 weight percent (dry coal basis). This report covers the 1994 operations and accomplishments.« less

Continuous bench-scale slurry catalyst testing direct coal liquefaction of rawhide sub-bituminous coal

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bauman, R.F.; Coless, L.A.; Davis, S.M.

In 1992, the Department of Energy (DOE) sponsored research to demonstrate a dispersed catalyst system using a combination of molybdenum and iron precursors for direct coal liquefaction. This dispersed catalyst system was successfully demonstrated using Black Thunder sub-bituminous coal at Wilsonville, Alabama by Southern Electric International, Inc. The DOE sponsored research continues at Exxon Research and Development Laboratories (ERDL). A six month continuous bench-scale program using ERDL`s Recycle Coal Liquefaction Unit (RCLU) is planned, three months in 1994 and three months in 1995. The initial conditions in RCLU reflect experience gained from the Wilsonville facility in their Test Run 263.more » Rawhide sub-bituminous coal which is similar to the Black Thunder coal tested at Wilsonville was used as the feed coal. A slate of five dispersed catalysts for direct coal liquefaction of Rawhide sub-bituminous coal has been tested. Throughout the experiments, the molybdenum addition rate was held constant at 100 wppm while the iron oxide addition rate was varied from 0.25 to 1.0 weight percent (dry coal basis). This report covers the 1994 operations and accomplishments.« less

Direct Determination of ECD in ECD Kit: A Solid Sample Quantitation Method for Active Pharmaceutical Ingredient in Drug Product

PubMed Central

Chao, Ming-Yu; Liu, Kung-Tien; Hsia, Yi-Chih; Liao, Mei-Hsiu; Shen, Lie-Hang

2011-01-01

Technetium-99m ethyl cysteinate dimer (Tc-99m-ECD) is an essential imaging agent used in evaluating the regional cerebral blood flow in patients with cerebrovascular diseases. Determination of active pharmaceutical ingredient, that is, L-Cysteine, N, N′-1,2-ethanediylbis-, diethyl ester, dihydrochloride (ECD) in ECD Kit is a relevant requirement for the pharmaceutical quality control in processes of mass fabrication. We here presented a direct solid sample determination method of ECD in ECD Kit without sample dissolution to avoid the rapid degradation of ECD. An elemental analyzer equipped with a nondispersive infrared detector and a calibration curve of coal standard was used for the quantitation of sulfur in ECD Kit. No significant matrix effect was found. The peak area of coal standard against the amount of sulfur was linear over the range of 0.03–0.10 mg, with a correlation coefficient (r) of 0.9993. Method validation parameters were achieved to demonstrate the potential of this method. PMID:21687539

Effects and mechanistic aspects of absorbing organic compounds by coking coal.

PubMed

Ning, Kejia; Wang, Junfeng; Xu, Hongxiang; Sun, Xianfeng; Huang, Gen; Liu, Guowei; Zhou, Lingmei

2017-11-01

Coal is a porous medium and natural absorbent. It can be used for its original purpose after adsorbing organic compounds, its value does not reduce and the pollutants are recycled, and then through systemic circulation of coking wastewater zero emissions can be achieved. Thus, a novel method of industrial organic wastewater treatment using adsorption on coal is introduced. Coking coal was used as an adsorbent in batch adsorption experiments. The quinoline, indole, pyridine and phenol removal efficiencies of coal adsorption were investigated. In addition, several operating parameters which impact removal efficiency such as coking coal consumption, oscillation contact time, initial concentration and pH value were also investigated. The coking coal exhibited properties well-suited for organics' adsorption. The experimental data were fitted to Langmuir and Freundlich isotherms as well as Temkin and Redlich-Peterson (R-P) models. The Freundlich isotherm model provided reasonable models of the adsorption process. Furthermore, the purification mechanism of organic compounds' adsorption on coking coal was analysed.

Federal coal follies: a new program ends (begins) a decade of anxiety

DOE Office of Scientific and Technical Information (OSTI.GOV)

Watson, J.L.

1980-01-01

The history, outline, and implementation of the new Federal Coal Management Program (FCMP) which has preoccupied the Department of Interior during the administrations of at least three presidents. The introduction briefly reviews the coal resource in the United States in general and the Federal coal resource in particular. Part II outlines the history of the Federal coal-leasing program over the decade of the 1970's. This is followed in Part III by a detailed discussion of the new FCMP which has been developed over the last two years and is now in the initial stages of implementation. Part III will focusmore » on the principal differences between the old and new coal programs. Part IV provides a critical review of the new program and discusses recommendations for revisions. Part V concludes that the future of Federal coal leasing may depend on whether the FCMP can generate the timely and defensible data needed to stimulate renewed coal development. 310 references, 6 figures, 2 tables.« less

Optimizing and Characterizing Geopolymers from Ternary Blend of Philippine Coal Fly Ash, Coal Bottom Ash and Rice Hull Ash.

PubMed

Kalaw, Martin Ernesto; Culaba, Alvin; Hinode, Hirofumi; Kurniawan, Winarto; Gallardo, Susan; Promentilla, Michael Angelo

2016-07-15

Geopolymers are inorganic polymers formed from the alkaline activation of amorphous alumino-silicate materials resulting in a three-dimensional polymeric network. As a class of materials, it is seen to have the potential of replacing ordinary Portland cement (OPC), which for more than a hundred years has been the binder of choice for structural and building applications. Geopolymers have emerged as a sustainable option vis-à-vis OPC for three reasons: (1) their technical properties are comparable if not better; (2) they can be produced from industrial wastes; and (3) within reasonable constraints, their production requires less energy and emits significantly less CO₂. In the Philippines, the use of coal ash, as the alumina- and silica- rich geopolymer precursor, is being considered as one of the options for sustainable management of coal ash generation from coal-fired power plants. However, most geopolymer mixes (and the prevalent blended OPC) use only coal fly ash. The coal bottom ash, having very few applications, remains relegated to dumpsites. Rice hull ash, from biomass-fired plants, is another silica-rich geopolymer precursor material from another significantly produced waste in the country with only minimal utilization. In this study, geopolymer samples were formed from the mixture of coal ash, using both coal fly ash (CFA) and coal bottom ash (CBA), and rice hull ash (RHA). The raw materials used for the geopolymerization process were characterized using X-ray fluorescence spectroscopy (XRF) for elemental and X-ray diffraction (XRD) for mineralogical composition. The raw materials' thermal stability and loss on ignition (LOI) were determined using thermogravimetric analysis (TGA) and reactivity via dissolution tests and inductively-coupled plasma mass spectrometry (ICP) analysis. The mechanical, thermal and microstructural properties of the geopolymers formed were analyzed using compression tests, Fourier transform infra-red spectroscopy (FTIR), scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). Using a Scheffé-based mixture design, targeting applications with low thermal conductivity, light weight and moderate strength and allowing for a maximum of five percent by mass of rice hull ash in consideration of the waste utilization of all three components, it has been determined that an 85-10-5 by weight ratio of CFA-CBA-RHA activated with 80-20 by mass ratio of 12 M NaOH and sodium silicate (55% H₂O, modulus = 3) produced geopolymers with a compressive strength of 18.5 MPa, a volumetric weight of 1660 kg/m³ and a thermal conductivity of 0.457 W/m-°C at 28-day curing when pre-cured at 80 °C for 24 h. For this study, the estimates of embodied energy and CO₂ were all below 1.7 MJ/kg and 0.12 kg CO₂/kg, respectively.

Distribution of arsenic, selenium, and other trace elements in high pyrite Appalachian coals: evidence for multiple episodes of pyrite formation

USGS Publications Warehouse

Diehl, S.F.; Goldhaber, M.B.; Koenig, A.E.; Lowers, H.A.; Ruppert, L.F.

2012-01-01

Pennsylvanian coals in the Appalachian Basin host pyrite that is locally enriched in potentially toxic trace elements such as As, Se, Hg, Pb, and Ni. A comparison of pyrite-rich coals from northwestern Alabama, eastern Kentucky, and West Virginia reveals differences in concentrations and mode of occurrence of trace elements in pyrite. Pyrite occurs as framboids, dendrites, or in massive crystalline form in cell lumens or crosscutting veins. Metal concentrations in pyrite vary over all scales, from microscopic to mine to regional, because trace elements are inhomogeneously distributed in the different morphological forms of pyrite, and in the multiple generations of sulfide mineral precipitates. Early diagenetic framboidal pyrite is usually depleted in As, Se, and Hg, and enriched in Pb and Ni, compared to other pyrite forms. In dendritic pyrite, maps of As distribution show a chemical gradient from As-rich centers to As-poor distal branches, whereas Se concentrations are highest at the distal edges of the branches. Massive crystalline pyrite that fills veins is composed of several generations of sulfide minerals. Pyrite in late-stage veins commonly exhibits As-rich growth zones, indicating a probable epigenetic hydrothermal origin. Selenium is concentrated at the distal edges of veins. A positive correlation of As and Se in pyrite veins from Kentucky coals, and of As and Hg in pyrite-filled veins from Alabama coals, suggests coprecipitation of these elements from the same fluid. In the Kentucky coal samples (n = 18), As and Se contents in pyrite-filled veins average 4200 ppm and 200 ppm, respectively. In Alabama coal samples, As in pyrite-filled veins averages 2700 ppm (n = 34), whereas As in pyrite-filled cellular structures averages 6470 ppm (n = 35). In these same Alabama samples, Se averages 80 ppm in pyrite-filled veins, but was below the detection limit in cell structures. In samples of West Virginia massive pyrite, As averages 1700 ppm, and Se averages 270 ppm (n = 24). The highest concentration of Hg (≤ 102 ppm) is in Alabama pyrite veins. Improved detailed descriptions of sulfide morphology, sulfide mineral paragenesis, and trace-element concentration and distribution allow more informed predictions of: (1) the relative rate of release of trace elements during weathering of pyrite in coals, and (2) the relative effectiveness of various coal-cleaning procedures of removing pyrite. For example, trace element-rich pyrite has been shown to be more soluble than stoichiometric pyrite, and fragile fine-grained pyrite forms such as dendrites and framboids are more susceptible to dissolution and disaggregation but less amenable to removal during coal cleaning.

76 FR 60965 - Western Coal Traffic League-Petition for Declaratory Order

Federal Register 2010, 2011, 2012, 2013, 2014

2011-09-30

... DEPARTMENT OF TRANSPORTATION Surface Transportation Board [Docket No. FD 35506] Western Coal Traffic League--Petition for Declaratory Order AGENCY: Surface Transportation Board. ACTION: Notice of declaratory order proceeding; request for comments. SUMMARY: The Board is initiating a declaratory order...

Green Energy for the Battlefield

DTIC Science & Technology

2007-12-01

Biodiesel, Ethanol, Natural Gas, Coal-Derived Liquid Fuels, Electricity , Greenhouse Gas, Emissions, Battlefield, Hybrid Vehicles 16. PRICE CODE 17...37 5. Electricity ............................................................................................38 C. CURRENT DOD RESEARCH AND...APPLICATIONS............................38 1. Coal-Derived Liquid Fuels – Assured Fuels Initiative ...................38 2. Electricity – Luke Air Force

State perspectives on clean coal technology deployment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Moreland, T.

1997-12-31

State governments have been funding partners in the Clean Coal Technology program since its beginnings. Today, regulatory and market uncertainties and tight budgets have reduced state investment in energy R and D, but states have developed program initiatives in support of deployment. State officials think that the federal government must continue to support these technologies in the deployment phase. Discussions of national energy policy must include attention to the Clean Coal Technology program and its accomplishments.

Applications of micellar enzymology to clean coal technology. [Laccase from Polyporus versicolor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Walsh, C.T.

1990-07-24

This project is designed to develop methods for pre-combustion coal remediation by implementing recent advances in enzyme biochemistry. The novel approach of this study is incorporation of hydrophilic oxidative enzymes in reverse micelles in an organic solvent. Enzymes from commercial sources or microbial extracts are being investigated for their capacity to remove organic sulfur from coal by oxidation of the sulfur groups, splitting of C-S bonds and loss of sulfur as sulfuric acid. Dibenzothiophen (DBT) and ethylphenylsulfide (EPS) are serving as models of organic sulfur-containing components of coal in initial studies.

Underground gasification of coal

DOEpatents

Pasini, III, Joseph; Overbey, Jr., William K.; Komar, Charles A.

1976-01-20

There is disclosed a method for the gasification of coal in situ which comprises drilling at least one well or borehole from the earth's surface so that the well or borehole enters the coalbed or seam horizontally and intersects the coalbed in a direction normal to its major natural fracture system, initiating burning of the coal with the introduction of a combustion-supporting gas such as air to convert the coal in situ to a heating gas of relatively high calorific value and recovering the gas. In a further embodiment the recovered gas may be used to drive one or more generators for the production of electricity.

Interrelating the breakage and composition of mined and drill core coal

NASA Astrophysics Data System (ADS)

Wilson, Terril Edward

Particle size distribution of coal is important if the coal is to be beneficiated, or if a coal sales contract includes particle size specifications. An exploration bore core sample of coal ought to be reduced from its original cylindrical form to a particle size distribution and particle composition that reflects, insofar as possible, a process stream of raw coal it represents. Often, coal cores are reduced with a laboratory crushing machine, the product of which does not match the raw coal size distribution. This study proceeds from work in coal bore core reduction by Australian investigators. In this study, as differentiated from the Australian work, drop-shatter impact breakage followed by dry batch tumbling in steel cylinder rotated about its transverse axis are employed to characterize the core material in terms of first-order and zeroth-order breakage rate constants, which are indices of the propensity of the coal to degrade during excavation and handling. Initial drop-shatter and dry tumbling calibrations were done with synthetic cores composed of controlled low-strength concrete incorporating fly ash (as a partial substitute for Portland cement) in order to reduce material variables and conserve difficult-to-obtain coal cores. Cores of three different coalbeds--Illinois No. 6, Upper Freeport, and Pocahontas No. 5 were subjected to drop-shatter and dry batch tumbling tests to determine breakage response. First-order breakage, characterized by a first-order breakage index for each coal, occurred in the drop-shatter tests. First- and zeroth-order breakage occurred in dry batch tumbling; disappearance of coarse particles and creation of fine particles occurred in a systematic way that could be represented mathematically. Certain of the coal cores available for testing were dry and friable. Comparison of coal preparation plant feed with a crushed bore core and a bore core prepared by drop-shatter and tumbling (all from the same Illinois No.6 coal mining property) indicated that the size distribution and size fraction composition of the drop-shattered/tumbled core more closely resembled the plant feed than the crushed core. An attempt to determine breakage parameters (to allow use of selection and breakage functions and population balance models in the description of bore core size reduction) was initiated. Rank determination of the three coal types was done, indicating that higher rank associates with higher breakage propensity. The two step procedure of drop-shatter and dry batch tumbling simulates the first-order (volume breakage) and zeroth-order (abrasion of particle surfaces) that occur in excavation and handling operations, and is appropriate for drill core reduction prior to laboratory analysis.

Respiratory Diseases Caused by Coal Mine Dust

PubMed Central

Laney, A. Scott; Weissman, David N.

2015-01-01

Objective To provide an update on respiratory diseases caused by coal mine dust. Methods This article presents the results of a literature review initially performed for an International Conference on Occupational and Environmental Lung Disease held in summer 2013. Results Coal mine dust causes a spectrum of lung diseases collectively termed coal mine dust lung disease (CMDLD). These include Coal Workers’ Pneumoconiosis, silicosis, mixed dust pneumoconiosis, dust-related diffuse fibrosis (which can be mistaken for idiopathic pulmonary fibrosis), and chronic obstructive pulmonary disease. CMDLD continues to be a problem in the United States, particularly in the central Appalachian region. Treatment of CMDLD is symptomatic. Those with end-stage disease are candidates for lung transplantation. Because CMDLD cannot be cured, prevention is critical. Conclusions Coal mine dust remains a relevant occupational hazard and miners remain at risk for CMDLD. PMID:25285970

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yuan, Ke; De Andrade, Vincent; Feng, Zhange

The presence of impurity ions is known to significantly influence mineral surface morphology during crystal growth from aqueous solution, but knowledge on impurity ion-mineral interactions during dissolution under far-from equilibrium conditions remains limited. Here we show that calcite (CaCO 3) exhibits a rich array of dissolution features in the presence of Pb. During the initial stage, calcite exhibits non-classical surface features characterized as micro pyramids developed spontaneously in acidic Pb-bearing solutions. Subsequent pseudomorphic growth of cerussite (PbCO 3) was observed, where nucleation occurred entirely within a pore space created by dissolution at the calcite/substrate interface. Uneven growth rates yielded amore » cerussite shell made of lath- or dendritic-shaped crystals. The cerussite phase was separated from the calcite by pores of less than 200 nm under transmission X-ray microscopy, consistent with the interface-coupled dissolution-precipitation mechanism. These results show that impurity metal ions exert significant control over the microscale dissolution features found on mineral surfaces and provide new insights into interpreting and designing micro structures observed in naturally-occurring and synthetic carbonate minerals by dissolution. In addition, heterogeneous micro-environments created in transport limited reactions under pore spaces may lead to unusual growth forms during crystal nucleation and precipitation.« less

30 CFR 715.11 - General obligations.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Mineral Resources OFFICE OF SURFACE MINING RECLAMATION AND ENFORCEMENT, DEPARTMENT OF THE INTERIOR INITIAL... surface coal mining and reclamation operations conducted on lands where any element of the operations is... are established by part 716 of this chapter for— (1) Surface coal mining operations on steep slopes...

Subtask 3.9 - Direct Coal Liquefaction Process Development

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aulich, Ted; Sharma, Ramesh

The Energy and Environmental Research Center (EERC), in partnership with the U.S. Department of Energy (DOE) and Accelergy Corporation, an advanced fuels developer with technologies exclusively licensed from ExxonMobil, undertook Subtask 3.9 to design, build, and preliminarily operate a bench-scale direct coal liquefaction (DCL) system capable of converting 45 pounds/hour of pulverized, dried coal to a liquid suitable for upgrading to fuels and/or chemicals. Fabrication and installation of the DCL system and an accompanying distillation system for off-line fractionation of raw coal liquids into 1) a naphtha middle distillate stream for upgrading and 2) a recycle stream was completed inmore » May 2012. Shakedown of the system was initiated in July 2012. In addition to completing fabrication of the DCL system, the project also produced a 500-milliliter sample of jet fuel derived in part from direct liquefaction of Illinois No. 6 coal, and submitted the sample to the Air Force Research Laboratory (AFRL) at Wright Patterson Air Force Base, Dayton, Ohio, for evaluation. The sample was confirmed by AFRL to be in compliance with all U.S. Air Force-prescribed alternative aviation fuel initial screening criteria.« less

Economic assessment of coal-burning locomotives: Topical report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1986-02-01

The General Electric Company embarked upon a study to evaluate various alternatives for the design and manufacture a coal fired locomotive considering various prime movers, but retaining the electric drive transmission. The initial study was supported by the Burlington-Northern and Norfolk-Southern railroads, and included the following alternatives: coal fired diesel locomotive; direct fired gas turbine locomotives; direct fired gas turbine locomotive with steam injection; raw coal gasifier gas turbine locomotive; and raw coal fluid bed steam turbine locomotive. All alternatives use the electric drive transmission and were selected for final evaluation. The first three would use a coal water slurrymore » as a fuel, which must be produced by new processing plants. Therefore, use of a slurry would require a significant plant capital investment. The last two would use classified run-of-the-mine (ROM) coal with much less capital expenditure. Coal fueling stations would be required but are significantly lower in capital cost than a coal slurry plant. For any coal fired locomotive to be commercially viable, it must pass the following criteria: be technically feasible and environmentally acceptable; meet railroads' financial expectations; and offer an attractive return to the locomotive manufacturer. These three criteria are reviewed in the report.« less

Effects of Gas Pressure on the Failure Characteristics of Coal

NASA Astrophysics Data System (ADS)

Xie, Guangxiang; Yin, Zhiqiang; Wang, Lei; Hu, Zuxiang; Zhu, Chuanqi

2017-07-01

Several experiments were conducted using self-developed equipment for visual gas-solid coupling mechanics. The raw coal specimens were stored in a container filled with gas (99% CH4) under different initial gas pressure conditions (0.0, 0.5, 1.0, and 1.5 MPa) for 24 h prior to testing. Then, the specimens were tested in a rock-testing machine, and the mechanical properties, surface deformation and failure modes were recorded using strain gauges, an acoustic emission (AE) system and a camera. An analysis of the fractals of fragments and dissipated energy was performed to understand the changes observed in the stress-strain and crack propagation behaviour of the gas-containing coal specimens. The results demonstrate that increased gas pressure leads to a reduction in the uniaxial compression strength (UCS) of gas-containing coal and the critical dilatancy stress. The AE, surface deformation and fractal analysis results show that the failure mode changes during the gas state. Interestingly, a higher initial gas pressure will cause the damaged cracks and failure of the gas-containing coal samples to become severe. The dissipated energy characteristic in the failure process of a gas-containing coal sample is analysed using a combination of fractal theory and energy principles. Using the theory of fracture mechanics, based on theoretical analyses and calculations, the stress intensity factor of crack tips increases as the gas pressure increases, which is the main cause of the reduction in the UCS and critical dilatancy stress and explains the influence of gas in coal failure. More serious failure is created in gas-containing coal under a high gas pressure and low exterior load.

Evaluation of ERDA-sponsored coal feed system development

NASA Technical Reports Server (NTRS)

Phen, R. L.; Luckow, W. K.; Mattson, L.; Otth, D.; Tsou, P.

1977-01-01

Coal feeders were evaluated based upon criteria such as technical feasibility, performance (i.e. ability to meet process requirements), projected life cycle costs, and projected development cost. An initial set of feeders was selected based on the feeders' cost savings potential compared with baseline lockhopper systems. Additional feeders were considered for selection based on: (1) increasing the probability of successful feeder development; (2) application to specific processes; and (3) technical merit. A coal feeder development program is outlined.

Initial Drug Dissolution from Amorphous Solid Dispersions Controlled by Polymer Dissolution and Drug-Polymer Interaction.

PubMed

Chen, Yuejie; Wang, Shujing; Wang, Shan; Liu, Chengyu; Su, Ching; Hageman, Michael; Hussain, Munir; Haskell, Roy; Stefanski, Kevin; Qian, Feng

2016-10-01

To identify the key formulation factors controlling the initial drug and polymer dissolution rates from an amorphous solid dispersion (ASD). Ketoconazole (KTZ) ASDs using PVP, PVP-VA, HMPC, or HPMC-AS as polymeric matrix were prepared. For each drug-polymer system, two types of formulations with the same composition were prepared: 1. Spray dried dispersion (SDD) that is homogenous at molecular level, 2. Physical blend of SDD (80% drug loading) and pure polymer (SDD-PB) that is homogenous only at powder level. Flory-Huggins interaction parameters (χ) between KTZ and the four polymers were obtained by Flory-Huggins model fitting. Solution (13)C NMR and FT-IR were conducted to investigate the specific drug-polymer interaction in the solution and solid state, respectively. Intrinsic dissolution of both the drug and the polymer from ASDs were studied using a Higuchi style intrinsic dissolution apparatus. PXRD and confocal Raman microscopy were used to confirm the absence of drug crystallinity on the tablet surface before and after dissolution study. In solid state, KTZ is completely miscible with PVP, PVP-VA, or HPMC-AS, demonstrated by the negative χ values of -0.36, -0.46, -1.68, respectively; while is poorly miscible with HPMC shown by a positive χ value of 0.23. According to solution (13)C NMR and FT-IR studies, KTZ interacts with HPMC-AS strongly through H-bonding and dipole induced interaction; with PVPs and PVP-VA moderately through dipole-induced interactions; and with HPMC weakly without detectable attractive interaction. Furthermore, the "apparent" strength of drug-polymer interaction, measured by the extent of peak shift on NMR or FT-IR spectra, increases with the increasing number of interacting drug-polymer pairs. For ASDs with the presence of considerable drug-polymer interactions, such as KTZ/PVPs, KTZ/PVP-VA, or KTZ /HPMC-AS systems, drug released at the same rate as the polymer when intimate drug-polymer mixing was ensured (i.e., the SDD systems); while drug released much slower than the polymer when molecular level mixing or drug-polymer interaction was absent (SDD-PB systems). For ASDs without drug-polymer interaction (i.e., KTZ/HPMC systems), the mixing homogeneity had little impact on the release rate of either the drug or the polymer thus SDD and SDD-PB demonstrated the same drug or polymer release rate, while the drug released slowly and independently of polymer release. The initial drug release from an ASD was controlled by 1) the polymer release rate; 2) the strength of drug-polymer interaction, including the intrinsic interaction caused by the chemistry of the drug and the polymer (measured by the χ value), as well as that the apparent interaction caused by the drug-polymer ratio (measure by the extent of peak shift on spectroscopic analysis); and 3) the level of mixing homogeneity between the drug and polymer. In summary, the selection of polymer, drug-polymer ratio, and ASD processing conditions have profound impacts on the dissolution behavior of ASDs. Graphical Abstract Relationship between initial drug and polymer dissolution rates from amorphous solid dispersions with different mixing uniformity and drug-polymer interactions.

Formation and dissolution of bacterial colonies.

PubMed

Weber, Christoph A; Lin, Yen Ting; Biais, Nicolas; Zaburdaev, Vasily

2015-09-01

Many organisms form colonies for a transient period of time to withstand environmental pressure. Bacterial biofilms are a prototypical example of such behavior. Despite significant interest across disciplines, physical mechanisms governing the formation and dissolution of bacterial colonies are still poorly understood. Starting from a kinetic description of motile and interacting cells we derive a hydrodynamic equation for their density on a surface, where most of the kinetic coefficients are estimated from experimental data for N. gonorrhoeae bacteria. We use it to describe the formation of multiple colonies with sizes consistent with experimental observations. Finally, we show how the changes in the cell-to-cell interactions lead to the dissolution of the bacterial colonies. The successful application of kinetic theory to a complex far from equilibrium system such as formation and dissolution of living bacterial colonies potentially paves the way for the physical quantification of the initial stages of biofilm formation.

Mass Transport Phenomena Between Bubbles and Dissolved Gases in Liquids Under Reduced Gravity Conditions

NASA Technical Reports Server (NTRS)

Dewitt, K. J.; Brockwell, J. L.

1985-01-01

The long term objective of the experiment is to observe the dissolution of isolated, immobile gas bubbles of specified size and composition in a solvent liquid of known concentration in the reduced gravity environment of earth orbit. Preliminary bubble dissolution experiment conducted both in the NASA Lewis 2.2 sec drop tower and in normal gravity using SO2 - Toluene system were not completely successful in their objective. The method of gas injection and lack of bubble interface stabiliy experienced due to the extreme solubility of SO in Toluene has the effects of changing the problem from that of bubble dissolution to one of bubble formation stability and subsequent dissolution in a liquid of unknown initial solute concentration. Current work involves further experimentation in order to refine the bubble injection system and to investigate the concept of having a bubble with a critical radius in a state of unstable equilibrium.

Fe-Containing Allophane and Hisingerite Dissolution and Implications for Gale Crater, Mars

NASA Technical Reports Server (NTRS)

Ralston, S. J.; Hausrath, E. M.; Tschauner, O.; Rampe, E. B.; Clark-Hogancamp, J. V.; Christoffersen, R.

2017-01-01

The mass-normalized dissolution rates measured in this study demonstrate that hisingerite and Fe-substituted allophane dissolve rapidly, much faster than crystalline phyllosilicates such as nontronite and kaolinite that have similar compositions. In addition, hisingerite dissolves more rapidly than allophane. Future work will focus on measuring dissolution rates at other pH values, so that dissolution rate laws for allophane and hisingerite can be derived. Results will be used to interpret data from Gale Crater. These initial experiments suggest that, if the liquid water present in Gale Crater was highly acidic, it was likely present for only a short time, allowing some amorphous soil-material similar to allophane to persist. Further experiments will enable us to constrain the timescales over which liquid water was present in Gale Crater and provide insight into its pH. This information is essential to assessing the potential habitability of ancient Mars.

Effects of ammonium on uranium partitioning and kaolinite mineral dissolution.

PubMed

Emerson, Hilary P; Di Pietro, Silvina; Katsenovich, Yelena; Szecsody, Jim

2017-02-01

Ammonia gas injection is a promising technique for the remediation of uranium within the vadose zone. It can be used to manipulate the pH of a system and cause co-precipitation processes that are expected to remove uranium from the aqueous phase and decrease leaching from the solid phase. The work presented in this paper explores the effects of ammonium and sodium hydroxide on the partitioning of uranium and dissolution of the kaolinite mineral in simplified synthetic groundwaters using equilibrium batch sorption and sequential extraction experiments. It shows that there is a significant increase in uranium removal in systems with divalent cations present in the aqueous phase but not in sodium chloride synthetic groundwaters. Further, the initial conditions of the aqueous phase do not affect the dissolution of kaolinite. However, the type of base treatment does have an effect on mineral dissolution. Published by Elsevier Ltd.

Rapid disintegrating tablets of simvastatin dispersions in polyoxyethylene–polypropylene block copolymer for maximized disintegration and dissolution

PubMed Central

Balata, Gehan F; Zidan, Ahmad S; Abourehab, Mohamad AS; Essa, Ebtessam A

2016-01-01

The objective of this research was to improve the dissolution of simvastatin and to incorporate it in rapid disintegrating tablets (RDTs) with an optimized disintegration and dissolution characteristics. Polyoxyethylene–polypropylene block copolymer (poloxamer 188) was employed as a hydrophilic carrier to prepare simvastatin solid dispersions (SDs). Fourier transform infrared spectroscopy, differential scanning calorimetry (DSC) and X-ray diffractometry were employed to understand the interaction between the drug and the carrier in the solid state. The results obtained from Fourier transform infrared spectroscopy showed absence of any chemical interaction between the drug and poloxamer. The results of differential scanning calorimetry and X-ray diffractometry confirmed the conversion of simvastatin to distorted crystalline state. The SD of 1:2 w/w drug to carrier ratio showed the highest dissolution; hence, it was incorporated in RDT formulations using a 32 full factorial design and response surface methodology. The initial assessments of RDTs demonstrated an acceptable flow, hardness, and friability to indicate good mechanical strength. The interaction and Pareto charts indicated that percentage of croscarmellose sodium incorporated was the most important factor affecting the disintegration time and dissolution parameter followed by the hardness value and their interaction effect. Compression force showed a superior influence to increase RDT’s porosity and to fasten disintegration rather than swelling action by croscarmellose sodium. On the other hand, croscarmellose sodium was most important for the initial simvastatin release. The results suggest the potential use of poloxamer 188-based SD in RDT for the oral delivery of poor water-soluble antihyperlipidemic drug, simvastatin. PMID:27757012

Characterization and modes of occurrence of elements in feed coal and coal combustion products from a power plant utilizing low-sulfur coal from the Powder River Basin, Wyoming

USGS Publications Warehouse

Brownfield, Michael E.; Cathcart, James D.; Affolter, Ronald H.; Brownfield, Isabelle K.; Rice, Cynthia A.; O'Connor, Joseph T.; Zielinski, Robert A.; Bullock, John H.; Hower, James C.; Meeker, Gregory P.

2005-01-01

The U.S. Geological Survey and the University of Kentucky Center for Applied Energy Research are collaborating with an Indiana utility company to determine the physical and chemical properties of feed coal and coal combustion products from a coal-fired power plant. The Indiana power plant utilizes a low-sulfur (0.23 to 0.47 weight percent S) and lowash (4.9 to 6.3 weight percent ash) subbituminous coal from the Wyodak-Anderson coal zone in the Tongue River Member of the Paleocene Fort Union Formation, Powder River Basin, Wyoming. Based on scanning electron microscope and X-ray diffraction analyses of feed coal samples, two mineral suites were identified: (1) a primary or detrital suite consisting of quartz (including beta-form grains), biotite, feldspar, and minor zircon; and (2) a secondary authigenic mineral suite containing alumino-phosphates (crandallite and gorceixite), kaolinite, carbonates (calcite and dolomite), quartz, anatase, barite, and pyrite. The primary mineral suite is interpreted, in part, to be of volcanic origin, whereas the authigenic mineral suite is interpreted, in part, to be the result of the alteration of the volcanic minerals. The mineral suites have contributed to the higher amounts of barium, calcium, magnesium, phosphorus, sodium, strontium, and titanium in the Powder River Basin feed coals in comparison to eastern coals. X-ray diffraction analysis indicates that (1) fly ash is mostly aluminate glass, perovskite, lime, gehlenite, quartz, and phosphates with minor amounts of periclase, anhydrite, hematite, and spinel group minerals; and (2) bottom ash is predominantly quartz, plagioclase (albite and anorthite), pyroxene (augite and fassaite), rhodonite, and akermanite, and spinel group minerals. Microprobe and scanning electron microscope analyses of fly ash samples revealed quartz, zircon, and monazite, euhedral laths of corundum with merrillite, hematite, dendritic spinels/ferrites, wollastonite, and periclase. The abundant calcium and magnesium mineral phases in the fly ash are attributed to the presence of carbonate, clay, and phosphate minerals in the feed coal and their alteration to new phases during combustion. The amorphous diffraction-scattering maxima or glass 'hump' appears to reflect differences in chemical composition of fly ash and bottom ash glasses. In Wyodak-Anderson fly and bottom ashes, the center point of scattering maxima is due to calcium and magnesium content, whereas the glass 'hump' of eastern fly ash reflects variation in aluminum content. The calcium- and magnesium-rich and alumino-phosphate mineral phases in the coal combustion products can be attributed to volcanic minerals deposited in peat-forming mires. Dissolution and alteration of these detrital volcanic minerals occurred either in the peat-forming stage or during coalification and diagenesis, resulting in the authigenic mineral suite. The presence of free lime (CaO) in fly ash produced from Wyodak-Anderson coal acts as a self-contained 'scrubber' for SO3, where CaO + SO3 form anhydrite either during combustion or in the upper parts of the boiler. Considering the high lime content in the fly ash and the resulting hydration reactions after its contact with water, there is little evidence that major amounts of leachable metals are mobilized in the disposal or utilization of this fly ash.

Low salinity hydrocarbon water disposal through deep subsurface drip irrigation: leaching of native selenium

USGS Publications Warehouse

Bern, Carleton R.; Engle, Mark A.; Boehlke, Adam R.; Zupancic, John W.; Brown, Adrian; Figueroa, Linda; Wolkersdorfer, Christian

2013-01-01

A subsurface drip irrigation system is being used in Wyoming’s Powder River Basin that treats high sodium, low salinity, coal bed methane (CBM) produced water with sulfuric acid and injects it into cropped fields at a depth of 0.92 m. Dissolution of native gypsum releases calcium that combats soil degradation that would otherwise result from high sodium water. Native selenium is leached from soil by application of the CBM water and traces native salt mobilization to groundwater. Resulting selenium concentrations in groundwater at this alluvial site were generally low (0.5–23 μg/L) compared to Wyoming’s agricultural use suitability standard (20 μg/L).

Effect of electrolyte temperature on the formation of self-organized anodic niobium oxide microcones in hot phosphate-glycerol electrolyte

NASA Astrophysics Data System (ADS)

Yang, S.; Aoki, Y.; Habazaki, H.

2011-07-01

Nanoporous niobium oxide films with microcone-type surface morphology were formed by anodizing at 10 V in glycerol electrolyte containing 0.6 mol dm -3 K 2HPO 4 and 0.2 mol dm -3 K 3PO 4 in a temperature range of 428-453 K. The microcones appeared after prolonged anodizing, but the required time was largely reduced by increasing electrolyte temperature. The anodic oxide was initially amorphous at all temperatures, but crystalline oxide nucleated during anodizing. The anodic oxide microcones, which were crystalline, appeared on surface as a consequence of preferential chemical dissolution of initially formed amorphous oxide. The chemical dissolution of an initially formed amorphous layer was accelerated by increasing the electrolyte temperature, with negligible influence of the temperature on the morphology of microcones up to 448 K.

Fate(s) of injected CO2 in a coal-bearing formation, Louisiana, Gulf Coast Basin: Chemical and isotopic tracers of microbial-brine-rock-CO2 interactions

USGS Publications Warehouse

Shelton, Jenna L.

2013-01-01

Coal beds are one of the most promising reservoirs for geologic carbon dioxide (CO₂) sequestration, as CO₂ can strongly adsorb onto organic matter and displace methane; however, little is known about the long-term fate of CO₂ sequestered in coal beds. The "2800' sand" of the Olla oil field is a coal-bearing, oil and gas-producing reservoir of the Paleocene–Eocene Wilcox Group in north-central Louisiana. In the 1980s, this field, specifically the 2800' sand, was flooded with CO₂ in an enhanced oil recovery (EOR) project, with 9.0×10⁷m³ of CO₂ remaining in the 2800' sand after injection ceased. This study utilized isotopic and geochemical tracers from co-produced natural gas, oil and brine from reservoirs located stratigraphically above, below and within the 2800' sand to determine the fate of the remaining EOR-CO₂, examining the possibilities of CO₂ migration, dissolution, mineral trapping, gas-phase trapping, and sorption to coal beds, while also testing a previous hypothesis that EOR-CO₂ may have been converted by microbes (CO₂-reducing methanogens) into methane, creating a microbial "hotspot". Reservoirs stratigraphically-comparable to the 2800' sand, but located in adjacent oil fields across a 90-km transect were sampled to investigate regional trends in gas composition, brine chemistry and microbial activity. The source field for the EOR-CO₂, the Black Lake Field, was also sampled to establish the δ¹³C-CO₂ value of the injected gas (0.9‰ +/- 0.9‰). Four samples collected from the Olla 2800' sand produced CO₂-rich gas with δ¹³C-CO₂ values (average 9.9‰) much lower than average (pre-injection) conditions (+15.9‰, average of sands located stratigraphically below the 2800' sand in the Olla Field) and at much higher CO₂ concentrations (24.9 mole %) than average (7.6 mole %, average of sands located stratigraphically below the 2800' sand in the Olla Field), suggesting the presence of EOR-CO₂ and gas-phase trapping as a major storage mechanism. Using δ¹³C values of CO₂ and dissolved organic carbon (DIC), CO₂ dissolution was also shown to be a major storage mechanism for 3 of the 4 samples from the Olla 2800' sand. Minor storage mechanisms were shown to be migration, which only affected 2 samples (from 1 well), and some EOR-CO₂ conversion to microbial methane for 3 of the 4 Olla 2800' sand samples. Since methanogenesis was not shown to be a major storage mechanism for the EOR-CO₂ in the Olla Field (CO₂ injection did not stimulate methanogenesis), samples were examined from adjacent oil fields to determine the cause of the Olla microbial "hot-spot". Microbial methane was found in all oil fields sampled, but indicators of methanogenesis (e.g. alkalinity, high δ¹³C-DIC values) were the greatest in the Olla Field, and the environmental conditions (salinity, pH, temperature) were most ideal for microbial CO₂ reduction in the Olla field, compared to adjacent fields.

Preventing Vision Loss from Blast Injuries with Regenerative Biomaterial

DTIC Science & Technology

2011-12-01

photorefractive keratectomy ( PRK ) procedure, which can be used to monitor epithelial healing rates. It was shown that the curved silk film bandage could...dissolution time on epithelial regeneration The PRK injury model was utilized to assess the rabbit cornea’s initial response to the application of the silk...dissolution time as compared to trial 1 within water. The PRK debridement procedure was performed and tracked over time with fluorescein staining. The films

The dissolution or growth of a gas bubble inside a drop in zero gravity

NASA Technical Reports Server (NTRS)

Kondos, Pericles A.; Subramanian, R. Shankar; Weinberg, Michael C.

1987-01-01

The radius-time history of a gas bubble located concentrically within a spherical liquid drop in a space laboratory is analyzed within the framework of the quasi-stationary approximation. Illustrative results are calculated from the theory which demonstrate interesting qualitative features. For instance, when a pure gas bubble dissolves within a liquid drop in an environment containing the same gas and some inert species, the dissolution can be more or less rapid than that in an unbounded liquid depending on the initial relative size of the drop. Further, given a similar growth situation, indefinite growth is not possible, and the bubble will initially grow, but always dissolve in the end.

PILOT SCALE PROCESS EVALUATION OF REBURNING FOR IN-FURNACE NOX REDUCTION

EPA Science Inventory

The report gives results of coal and natural gas reburning application tests to a pilot scale 3.0 MWt furnace to provide the scaling information required for commercial application of reburning to pulverized-coal-fired boilers. Initial parametric studies had been conducted in a 2...

OVERBURDEN MINERALOGY AS RELATED TO GROUND-WATER CHEMICAL CHANGES IN COAL STRIP MINING

EPA Science Inventory

A research program was initiated to define and develop an inclusive, effective, and economical method for predicting potential ground-water quality changes resulting from the strip mining of coal in the Western United States. To utilize the predictive method, it is necessary to s...

ENVIRONMENTAL EFFECTS OF WESTERN COAL COMBUSTION. PART II. THE AQUATIC MACROINVERTEBRATES OF ROSEBUD CREEK, MONTANA

EPA Science Inventory

The aquatic macroinvertebrates of Rosebud Creek, Montana, were sampled between February 1976 and March 1977 to provide data on their abundance, distribution, and diversity. The sampling program was initiated during the first year of operation of the coal-fired power plants locate...

The dissolution of calcite in CO2-saturated solutions at 25°C and 1 atmosphere total pressure

USGS Publications Warehouse

Plummer, Niel; Wigley, T.M.L.

1976-01-01

The dissolution of Iceland spar in CO2-saturated solutions at 25°C and 1 atm total pressure has been followed by measurement of pH as a function of time. Surface concentrations of reactant and product species have been calculated from bulk fluid data using mass transport theory and a model that accounts for homogeneous reactions in the bulk fluid. The surface concentrations are found to be close to bulk solution values. This indicates that calcite dissolution under the experimental conditions is controlled by the kinetics of surface reaction. The rate of calcite dissolution follows an empirical second order relation with respect to calcium and hydrogen ion from near the initial condition (pH 3.91) to approximately pH 5.9. Beyond pH 5.9 the rate of surface reaction is greatly reduced and higher reaction orders are observed. Calculations show that the rate of calcite dissolution in natural environments may be influenced by both transport and surface-reaction processes. In the absence of inhibition, relatively short times should be sufficient to establish equilibrium.

[Leaching of Rare Earth Elements from Coal Ashes Using Acidophilic Chemolithotrophic Microbial Communities].

PubMed

Muravyov, M I; Bulaev, A G; Melamud, V S; Kondrat'eva, T F

2015-01-01

A method for leaching rare earth elements from coal ash in the presence of elemental sulfur using communities of acidophilic chemolithotrophic microorganisms was proposed. The optimal parameters determined for rare element leaching in reactors were as follows: temperature, 45 degrees C; initial pH, 2.0; pulp density, 10%; and the coal ash to elemental sulfur ratio, 10 : 1. After ten days of leaching, 52.0, 52.6, and 59.5% of scandium, yttrium, and lanthanum, respectively, were recovered.

On-line determination of the ash content in coal using industrial, natural gamma-ray equipment

NASA Astrophysics Data System (ADS)

Alvarez, M. C.; Dopico, M. T.

1995-12-01

This work presents phases of an investigation carried out in Spain to develop industrial natural-γ equipment to determine the ash content in coals. Initially the programme was on a laboratory scale and later tests were performed in a coal washing plant on a mixture of washed products. The results obtained are very satisfactory since the equipment permits the ash content to be determined with a mean error of 1.3% and a SD of 1.

A moving baseline for evaluation of advanced coal extraction systems

NASA Technical Reports Server (NTRS)

Bickerton, C. R.; Westerfield, M. D.

1981-01-01

Results from the initial effort to establish baseline economic performance comparators for a program whose intent is to define, develop, and demonstrate advanced systems suitable for coal resource extraction beyond the year 2000 are reported. Systems used were selected from contemporary coal mining technology and from conservation conjectures of year 2000 technology. The analysis was also based on a seam thickness of 6 ft. Therefore, the results are specific to the study systems and the selected seam extended to other seam thicknesses.

Channel-fill coal beds along the western margin of the Eastern Kentucky Coal Field

USGS Publications Warehouse

Eble, C.F.; Greb, S.F.

1997-01-01

Four channel-filling coal beds from the lower part of the Breathitt Formation (lower Middle Pennsylvanian, late Westphalian A) were examined palynologically, petrographically and geochemically to determine the paleoenvironmental conditions under which these peats accumulated. These results were then compared with detailed sedimentological analyses of the strata overlying the coal in the channels to see if any genetic relationship between coal composition and the origin of the overburden could be drawn. All four of the coal beds used in this study are located in the western-most part of the Eastern Kentucky Coal Field and occur at, or near, the Early Pennsylvanian unconformity (0-30 m). Lycospora and Densosporites (and related crassicingulate taxa, e.g. Cristatisporites, Cingulizonates and Radiizonates) dominate the studied assemblages, with Granulatisporites (and related trilete, sphaerotriangular genera, e.g. Leiotriletes and Lophotriletes), Laevigatosporites and Schulzospora being common accessory genera. Petrographically, all four coals contain high percentages of vitrinite macerals (avg. 78.6% mineral matter free), moderate amounts of liptinite (or exinite) macerals (avg. 14.9%, mmf) and low percentages of inertinite macerals (avg. 6.5%, mmf). Strata above the coals consist of dark, carbonaceous shales, and heterolithic strata that exhibit varying degrees of bioturbation. Commonly occurring trace fossils include Arenicolites, Monocraterion, Planolites and Skolithos. Although marine-influenced strata, as determined from detailed sedimentology and ichnology (the study of trace fossils), covers all four coal beds, they are not uniformly high in total total sulfur content as might be expected. Rather they are extremely variable, ranging from 1-9% (dry basis) total sulfur. Ash yields are also variable ranging from 6.2-54.3% (dry basis). It is probable that the origin of the very first sediments covering the peat, as well as the amount of brackish water influence during peat accumulation, were important factors in determining the total sulfur content of the resultant coal. Initial sedimentation of fresh water clays and silts may have acted as a barrier to downward percolation/diffusion of sulfate bearing waters, or may have served as a site for sulfide formation, thereby keeping the total sulfur content of the underlying coal low. If initial sedimentation was of brackish or marine origin, as indicated by bioturbated laminae directly above the coal, or if the peat was subject to frequent brackish or marine water influence during accumulation, then sulfide generation might proceed unchecked, resulting in high sulfur coal.

Biogenic coal-to-methane conversion efficiency decreases after repeated organic amendment

USGS Publications Warehouse

Davis, Katherine J.; Barnhart, Elliott P.; Fields, Matthew W.; Gerlach, Robin

2018-01-01

Addition of organic amendments to coal-containing systems can increase the rate and extent of biogenic methane production for 60–80 days before production slows or stops. Understanding the effect of repeated amendment additions on the rate and extent of enhanced coal-dependent methane production is important if biological coal-to-methane conversion is to be enhanced on a commercial scale. Microalgal biomass was added at a concentration of 0.1 g/L to microcosms with and without coal on days 0, 76, and 117. Rates of methane production were enhanced after the initial amendment but coal-containing treatments produced successively decreasing amounts of methane with each amendment. During the first amendment period, 113% of carbon added as amendment was recovered as methane, whereas in the second and third amendment periods, 39% and 32% of carbon added as amendment was recovered as methane, respectively. Additionally, algae-amended coal treatments produced ∼38% more methane than unamended coal treatments and ∼180% more methane than amended coal-free treatments after one amendment. However, a second amendment addition resulted in only an ∼25% increase in methane production for coal versus noncoal treatments and a third amendment addition resulted in similar methane production in both coal and noncoal treatments. Successive amendment additions appeared to result in a shift from coal-to-methane conversion to amendment-to-methane conversion. The reported results indicate that a better understanding is needed of the potential impacts and efficiencies of repeated stimulation for enhanced coal-to-methane conversion.

Solutal convection induced by dissolution. Influence on erosion dynamics and interface shaping.

NASA Astrophysics Data System (ADS)

Berhanu, Michael; Philippi, Julien; Cohen, Caroline; Derr, Julien; Courrech du Pont, Sylvain

2017-04-01

Rock fractures invaded by a water flow, are often subjected to dissolution, which let grow and evolve the initial fracture network, by evacuating the eroded minerals under a solute form. In the case of fast kinetic of dissolution, local erosion rate is set by the advection of the solute. The erosion velocity decreases indeed with the solute concentration at the interface and vanishes when this concentration reaches the saturation value. Even in absence of an imposed or external flow, advection can drive the dissolution, when buoyancy effects due to gravity induce a solutal convection flow, which controls the erosive dynamics and modifies the shape of the dissolving interface. Here, we investigate using model experiments with fast dissolving materials and numerical simulations in simplified situations, solutal convection induced by dissolution. Results are interpreted regarding a linear stability analysis of the corresponding solutal Rayleigh-Benard instability. A dissolving surface is suspended above a water height, initially at rest. In a first step, solute flux is transported through a growing diffusion layer. Then after an onset time, once the layer exceeds critical width, convection flow starts under the form of falling plumes. A dynamic equilibrium results in average from births and deaths of intermittent plumes, setting the size of the solute concentration boundary layer at the interface and thus the erosion velocity. Solutal convection can also induce a pattern on the dissolving interface. We show experimentally with suspended and inclined blocks of salt and sugar, that in a linear stage, the first wavelength of the dissolution pattern corresponds to the wavelength of the convection instability. Then pattern evolves to more complex shapes due to non-linear interactions between the flow and the eroded interface. More generally, we inquire what are the conditions to observe a such solutal convection instability in geological situations and if the properties of dissolution patterns can be related to the characteristic of the convective flow. C. Oltéan, F. Golfier and M.A. Buès, Numerical and experimental investigation of buoyancy-driven dissolution in vertical fracture, J. Geophys. Res. Solid Earth, 118(5), 2038-2048 (2013) C. Cohen, M. Berhanu, J. Derr and S. Courrech du Pont, Erosion patterns on dissolving and melting bodies (2015 Gallery of Fluid motion), Phys. Rev. Fluids, 1, 050508 (2016) T. S. Sullivan, Y. Liu, and R. E. Ecke, Turbulent solutal convection and surface patterning in solid dissolution, Phys. Rev. E 54, 486 (1996)

In situ nano- to microscopic imaging and growth mechanism of electrochemical dissolution (e.g., corrosion) of a confined metal surface

PubMed Central

Merola, C.; Cheng, H.-W.; Schwenzfeier, K.; Kristiansen, K.; Chen, Y.-J.; Dobbs, H. A.; Valtiner, M.

2017-01-01

Reactivity in confinement is central to a wide range of applications and systems, yet it is notoriously difficult to probe reactions in confined spaces in real time. Using a modified electrochemical surface forces apparatus (EC-SFA) on confined metallic surfaces, we observe in situ nano- to microscale dissolution and pit formation (qualitatively similar to previous observation on nonmetallic surfaces, e.g., silica) in well-defined geometries in environments relevant to corrosion processes. We follow “crevice corrosion” processes in real time in different pH-neutral NaCl solutions and applied surface potentials of nickel (vs. Ag|AgCl electrode in solution) for the mica–nickel confined interface of total area ∼0.03 mm2. The initial corrosion proceeds as self-catalyzed pitting, visualized by the sudden appearance of circular pits with uniform diameters of 6–7 μm and depth ∼2–3 nm. At concentrations above 10 mM NaCl, pitting is initiated at the outer rim of the confined zone, while below 10 mM NaCl, pitting is initiated inside the confined zone. We compare statistical analysis of growth kinetics and shape evolution of individual nanoscale deep pits with estimates from macroscopic experiments to study initial pit growth and propagation. Our data and experimental techniques reveal a mechanism that suggests initial corrosion results in formation of an aggressive interfacial electrolyte that rapidly accelerates pitting, similar to crack initiation and propagation within the confined area. These results support a general mechanism for nanoscale material degradation and dissolution (e.g., crevice corrosion) of polycrystalline nonnoble metals, alloys, and inorganic materials within confined interfaces. PMID:28827338

Electrical Resistivity Tomography for coal fire mapping over Jharia coal field, India

NASA Astrophysics Data System (ADS)

Pal, S. K.; Kumar, S.; Bharti, A. K.; Pathak, V. K.; Kumar, R.

2016-12-01

Over the decades, coal fires are serious global concern posing grievous hazards to the valuable energy resources, local environments and human life. The coal seam and coal mine fires may be initiated due to improper mining activities, exothermic reactions, lighting, forest fire and other anthropic activities, which burn the coal and may continue underground for decades. The burning of concealed coal seams is a complex process involving numerous ill-defined parameters. Generally, the coal exhibits resistivity of 100 to 500Ωm at normal temperature conditions. During the pyrolysis process, at temperatures greater than 6500C coal became a good conductor with a resistivity of approximately 1 Ωm. The present study deals with the mapping of coal fire over Jharia coal field, India using Electrical Resistivity Tomography (ERT). A state-of-the-art 61-channel 64 electrode FlashRES-Universal ERT data acquisition system has been used for data acquisition in the field. The ERT data have been collected using Gradient array and processed in FlashRES Universal survey data checking program for removing noisy data. Then, filtered output data have been inverted using a 2.5D resistivity inversion program. Low resistivity anomalies over 80m-125m and 320m-390m along the profile are inferred to be active coal fire in seam- XVI at a depth of 25m -35m(Figure 1). High resistivity anomaly over 445m - 510m at a depth of 25m -35m has been delineated, due to void associated with complete combustion of seam- XVI coal, followed by char and ash formation resulting from the coal seam fire. Results prove the efficacy of the ERT study comprising Gradient array for coal fire mapping over, Jharia coal field, India.

Pb 2+–Calcite Interactions under Far-from-Equilibrium Conditions: Formation of Micropyramids and Pseudomorphic Growth of Cerussite

DOE PAGES

Yuan, Ke; De Andrade, Vincent; Feng, Zhange; ...

2018-01-04

The presence of impurity ions is known to significantly influence mineral surface morphology during crystal growth from aqueous solution, but knowledge on impurity ion-mineral interactions during dissolution under far-from equilibrium conditions remains limited. Here we show that calcite (CaCO 3) exhibits a rich array of dissolution features in the presence of Pb. During the initial stage, calcite exhibits non-classical surface features characterized as micro pyramids developed spontaneously in acidic Pb-bearing solutions. Subsequent pseudomorphic growth of cerussite (PbCO 3) was observed, where nucleation occurred entirely within a pore space created by dissolution at the calcite/substrate interface. Uneven growth rates yielded amore » cerussite shell made of lath- or dendritic-shaped crystals. The cerussite phase was separated from the calcite by pores of less than 200 nm under transmission X-ray microscopy, consistent with the interface-coupled dissolution-precipitation mechanism. These results show that impurity metal ions exert significant control over the microscale dissolution features found on mineral surfaces and provide new insights into interpreting and designing micro structures observed in naturally-occurring and synthetic carbonate minerals by dissolution. In addition, heterogeneous micro-environments created in transport limited reactions under pore spaces may lead to unusual growth forms during crystal nucleation and precipitation.« less

Effect of ball milling on the physicochemical properties of atorvastatin calcium sesquihydrate: the dissolution kinetic behaviours of milled amorphous solids.

PubMed

Kobayashi, Makiko; Hattori, Yusuke; Sasaki, Tetsuo; Otsuka, Makoto

2017-01-01

The purposes of this study were to clarify the amorphization by ball milling of atorvastatin calcium sesquihydrate (AT) and to analyse the change in dissolution kinetics. The amorphous AT was prepared from crystal AT by ball milling and analysed in terms of the changes of its physicochemical properties by powder X-ray diffraction analysis (XRD), thermal analysis and infrared spectroscopy (IR). Moreover, to evaluate the usefulness of the amorphous form for pharmaceutical development, intrinsic solubility of the ground product was evaluated using a dissolution kinetic method. The XRD results indicated that crystalline AT was transformed into amorphous solids by more than 30-min milling. The thermal analysis result suggested that chemical potential of the ground AT are changed significantly by milling. The IR spectra of the AT showed the band shift from the amide group at 3406 cm -1 with an intermolecular hydrogen bond to a free amide group at 3365 cm -1 by milling. The dissolution of amorphous AT follows a dissolution kinetic model involving phase transformation. The initial dissolution rate of the ground product increased with the increase in milling time to reflect the increase in the intrinsic solubility based on the amorphous state. © 2016 Royal Pharmaceutical Society.

Dynamic reservoir-condition microtomography of reactive transport in complex carbonates: Effect of initial pore structure and initial brine pH

NASA Astrophysics Data System (ADS)

Menke, H. P.; Bijeljic, B.; Blunt, M. J.

2017-05-01

We study the impact of brine acidity and initial pore structure on the dynamics of fluid/solid reaction at high Péclet numbers and low Damköhler numbers. A laboratory μ-CT scanner was used to image the dissolution of Ketton, Estaillades, and Portland limestones in the presence of CO2-acidified brine at reservoir conditions (10 MPa and 50 °C) at two injected acid strengths for a period of 4 h. Each sample was scanned between 6 and 10 times at ∼4 μm resolution and multiple effluent samples were extracted. The images were used as inputs into flow simulations, and analysed for dynamic changes in porosity, permeability, and reaction rate. Additionally, the effluent samples were used to verify the image-measured porosity changes. We find that initial brine acidity and pore structure determine the type of dissolution. Dissolution is either uniform where the porosity increases evenly both spatially and temporally, or occurs as channelling where the porosity increase is concentrated in preferential flow paths. Ketton, which has a relatively homogeneous pore structure, dissolved uniformly at pH = 3.6 but showed more channelized flow at pH = 3.1. In Estaillades and Portland, increasingly complex carbonates, channelized flow was observed at both acidities with the channel forming faster at lower pH. It was found that the effluent pH, which is higher than that injected, is a reasonably good indicator of effective reaction rate during uniform dissolution, but a poor indicator during channelling. The overall effective reaction rate was up to 18 times lower than the batch reaction rate measured on a flat surface at the effluent pH, with the lowest reaction rates in the samples with the most channelized flow, confirming that transport limitations are the dominant mechanism in determining reaction dynamics at the fluid/solid boundary.

Optimizing and Characterizing Geopolymers from Ternary Blend of Philippine Coal Fly Ash, Coal Bottom Ash and Rice Hull Ash

PubMed Central

Kalaw, Martin Ernesto; Culaba, Alvin; Hinode, Hirofumi; Kurniawan, Winarto; Gallardo, Susan; Promentilla, Michael Angelo

2016-01-01

Geopolymers are inorganic polymers formed from the alkaline activation of amorphous alumino-silicate materials resulting in a three-dimensional polymeric network. As a class of materials, it is seen to have the potential of replacing ordinary Portland cement (OPC), which for more than a hundred years has been the binder of choice for structural and building applications. Geopolymers have emerged as a sustainable option vis-à-vis OPC for three reasons: (1) their technical properties are comparable if not better; (2) they can be produced from industrial wastes; and (3) within reasonable constraints, their production requires less energy and emits significantly less CO2. In the Philippines, the use of coal ash, as the alumina- and silica- rich geopolymer precursor, is being considered as one of the options for sustainable management of coal ash generation from coal-fired power plants. However, most geopolymer mixes (and the prevalent blended OPC) use only coal fly ash. The coal bottom ash, having very few applications, remains relegated to dumpsites. Rice hull ash, from biomass-fired plants, is another silica-rich geopolymer precursor material from another significantly produced waste in the country with only minimal utilization. In this study, geopolymer samples were formed from the mixture of coal ash, using both coal fly ash (CFA) and coal bottom ash (CBA), and rice hull ash (RHA). The raw materials used for the geopolymerization process were characterized using X-ray fluorescence spectroscopy (XRF) for elemental and X-ray diffraction (XRD) for mineralogical composition. The raw materials’ thermal stability and loss on ignition (LOI) were determined using thermogravimetric analysis (TGA) and reactivity via dissolution tests and inductively-coupled plasma mass spectrometry (ICP) analysis. The mechanical, thermal and microstructural properties of the geopolymers formed were analyzed using compression tests, Fourier transform infra-red spectroscopy (FTIR), scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). Using a Scheffé-based mixture design, targeting applications with low thermal conductivity, light weight and moderate strength and allowing for a maximum of five percent by mass of rice hull ash in consideration of the waste utilization of all three components, it has been determined that an 85-10-5 by weight ratio of CFA-CBA-RHA activated with 80-20 by mass ratio of 12 M NaOH and sodium silicate (55% H2O, modulus = 3) produced geopolymers with a compressive strength of 18.5 MPa, a volumetric weight of 1660 kg/m3 and a thermal conductivity of 0.457 W/m-°C at 28-day curing when pre-cured at 80 °C for 24 h. For this study, the estimates of embodied energy and CO2 were all below 1.7 MJ/kg and 0.12 kg CO2/kg, respectively. PMID:28773702

Microbial conversion of coal

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bean, R.M.

1989-10-01

The objectives of this project were to describe in detail the degradation of coals by fungi and microbes, to expand the range of applicability of the process to include new microbes and other coal types, to identify the means by which biosolubilization of coal is accomplished, and to explore means to enhance the rates and extent of coal bioconversion. The project was initiated in a response to the discovery by Dr. Martin Cohen at the University of Hartford, of a fungal strain of Coriolus versicolor that would render a solid coal substance, leonardite, into a liquid product. The project hasmore » identified the principal agent of leonardite solubilization as a powerful metal chelator, most likely a fungal-produced siderophore. Another nonlaccase enzyme has also been identified as a unique biosolubilizing agent produced by C. versicolor. Assays were developed for the quantitative determination of biological coal conversion, and for the determination of potency of biosolubilizing agent. Screening studies uncovered several microbial organisms capable of coal biodegradation, and led to the discovery that prolonged heating in air at the moderate temperature of 150{degree}C allowed the biodegradation of Illinois {number sign}6 coal to material soluble in dilute base. Chemical studies showed that leonardite biosolubilization was accompanied by relatively small change in composition, while solubilization of Illinois {number sign}6 coal involves considerable oxidation of the coal. 24 refs., 32 figs., 27 tabs.« less

Zinc isotopic composition of particulate matter generated during the combustion of coal and coal + tire-derived fuels

USGS Publications Warehouse

Borrok, D.M.; Gieré, R.; Ren, M.; Landa, E.R.

2010-01-01

Atmospheric Zn emissions from the burning of coal and tire-derived fuel (TDF) for power generation can be considerable. In an effort to lay the foundation for tracking these contributions, we evaluated the Zn isotopes of coal, a mixture of 95 wt % coal + 5 wt % TDF, and the particulate matter (PM) derived from their combustion in a power-generating plant. The average Zn concentrations and δ(66)Zn were 36 mg/kg and 183 mg/kg and +0.24‰ and +0.13‰ for the coal and coal + TDF, respectively. The δ(66)Zn of the PM sequestered in the cyclone-type mechanical separator was the lightest measured, -0.48‰ for coal and -0.81‰ for coal+TDF. The δ(66)Zn of the PM from the electrostatic precipitator showed a slight enrichment in the heavier Zn isotopes relative to the starting material. PM collected from the stack had the heaviest δ(66)Zn in the system, +0.63‰ and +0.50‰ for the coal and coal + TDF, respectively. Initial fractionation during the generation of a Zn-rich vapor is followed by temperature-dependent fractionation as Zn condenses onto the PM. The isotopic changes of the two fuel types are similar, suggesting that their inherent chemical differences have only a secondary impact on the isotopic fractionation process.

Zinc isotopic composition of particulate matter generated during the combustion of coal and coal + tire-derived fuels.

PubMed

Borrok, David M; Gieré, Reto; Ren, Minghua; Landa, Edward R

2010-12-01

Atmospheric Zn emissions from the burning of coal and tire-derived fuel (TDF) for power generation can be considerable. In an effort to lay the foundation for tracking these contributions, we evaluated the Zn isotopes of coal, a mixture of 95 wt % coal + 5 wt % TDF, and the particulate matter (PM) derived from their combustion in a power-generating plant. The average Zn concentrations and δ(66)Zn were 36 mg/kg and 183 mg/kg and +0.24‰ and +0.13‰ for the coal and coal + TDF, respectively. The δ(66)Zn of the PM sequestered in the cyclone-type mechanical separator was the lightest measured, -0.48‰ for coal and -0.81‰ for coal+TDF. The δ(66)Zn of the PM from the electrostatic precipitator showed a slight enrichment in the heavier Zn isotopes relative to the starting material. PM collected from the stack had the heaviest δ(66)Zn in the system, +0.63‰ and +0.50‰ for the coal and coal + TDF, respectively. Initial fractionation during the generation of a Zn-rich vapor is followed by temperature-dependent fractionation as Zn condenses onto the PM. The isotopic changes of the two fuel types are similar, suggesting that their inherent chemical differences have only a secondary impact on the isotopic fractionation process.

DNAPL remediation with in situ chemical oxidation using potassium permanganate - Part I. Mineralogy of Mn oxide and its dissolution in organic acids

NASA Astrophysics Data System (ADS)

Li, X. David; Schwartz, Franklin W.

2004-01-01

Previous studies on in situ chemical oxidation of trichloroethylene (TCE) with potassium permanganate indicated that the solid reaction product, Mn oxide, could reduce the permeability of the porous medium and impact the success of dense non-aqueous phase liquid (DNAPL) removal. In order to address the issue of permeability reduction caused by precipitation, this study investigated the mineralogy of Mn oxides and the possibilities of removing the solid precipitates by dissolution. The solid reaction product from the oxidation of TCE by permanganate is semi-amorphous potassium-rich birnessite, which has a layered mineral structure with an interlayer spacing of 7.3 Å. The chemical formula is K 0.854Mn 1.786O 4·1.55H 2O. It has a relatively small specific surface area at 23.6±0.82 m 2/g. Its point of zero charge (pzc) was measured as 3.7±0.4. This birnessite is a relatively active species and could participate in various reactions with existing organic and inorganic matter. The dissolution kinetics of Mn oxide was evaluated in batch experiments using solutions of citric acid, oxalic acid, and ethylenediaminetetraacetic acid (EDTA). Initial dissolution rates were determined to be 0.126 mM/m 2/h for citric acid, 1.35 mM/m 2/h for oxalic acid, and 5.176 mM/m 2/h for EDTA. These rates compare with 0.0025 mM/m 2/h for nitric acid at pH=2. Organic acids dissolve Mn oxide quickly. Reaction rates increase with acid concentration, as tested with citric acid. The dissolution mechanism likely involves proton and ligand-promoted dissolution and reductive dissolution. Citric and oxalic acid can induce ligand-promoted dissolution, while EDTA can induce ligand-promoted and reductive dissolutions. At low pH, proton-promoted dissolution seems to occur with all the acids tested, but this process is not dominant. Reductive dissolution appears to be the most effective process in dissolving the solid, followed by ligand-promoted dissolution. These experiments indicate the significant potential in using these organic acids to remove precipitates formed during the oxidation reaction.

Effects of drug-carrier interactions on drug dissolution from binary and ternary matrices

NASA Astrophysics Data System (ADS)

Iqbal, Zafar

For nearly five decades, pharmaceutical researchers have studied solid solutions of drugs in polymers as a potential means to enhance the dissolution of drugs with poor aqueous solubility. This has become of greater importance in recent years because most new potential drug compounds (new chemical entities) exhibit poor water solubility and present great challenges to scientists who must design dosage forms from which the drugs are bioavailable. During the formulation of a solid solution, the drug undergoes physical but not chemical alterations that increase its chemical potential in the formulation relative to that of the pure drug in its stable form. This increased chemical potential is responsible for enhanced dissolution as well as physical instabilities, such as amorphous to crystalline conversions and precipitation within the solid state. The chemical potential is derived from the Gibbs free energy, so it is reasonable to explain the behavior of solid solution systems in terms of thermodynamics. Solid solutions and dispersions have been extensively studied by pharmaceutical scientists, both with regard to manufacturing aspects and the proposal of various models in attempts to explain the physical bases for how these systems work. Recently, Dave and Bellantone proposed a model based on the thermodynamic changes resulting from the formulation of binary solid solutions of a drug in the polymer PVP. Their model introduced a modification of the F-H theory, which was used to quantify the drug-polymer interaction energies and calculate the entropy of mixing of the drug and polymer. In this work, the model of Dave and Bellantone was extended to include three-component systems, consisting of one drug mixed in a carrier matrix consisting of mixture of two polymers or a polymer and a surfactant. For this research, solid solutions were formed using various drug weight fractions in the formulations. The study focused on the following points: (1) Prepare solid solution formulations and perform appropriate physical characterizations. (2) Characterize the increase in drug dissolution rates resulting from solid solution formulations. (3) Relate the initial dissolution rates to the drug solubility. (4) Explain the solubility enhancement from solid solution dosage in terms of the drug polymer interactions using the extended thermodynamic model. Two poorly water soluble drugs, levonorgestrel (LEVO) and ethinyl estradiol (EE) were formulated in seven solid solution preparations comprised of four carrier systems. Materials used as carriers included various combinations of the polymers PVP K-30, Copovidone (COP), Poloxamer 182, and the surfactant TweenRTM 20. Additionally, ibuprofen (IBU) was used in three formulations consisting of various combinations of PVP K-30, Copovidone and TweenRTM 20. Formulations with various drug weight fractions (0.5%--30%) were prepared using the solvent evaporation technique. Each formulation was tested for dissolution using intrinsic dissolution apparatus (USP). The solid solutions were compressed into tablets into the sample die that maintained a constant surface area during the dissolution process. DSC, XRD and NIRS scans identified that the crystalline peaks of the drug disappeared with the addition of the polymer for all ratios of EE, indicating the formation of solid solutions (to within the limits of detection of the equipment). This was also observed for the LEVO dispersions up to 10% drug loading. At higher drug loading, solutions were formed but some small degree crystallinity was also present. For each experiment, the initial dissolution rates were obtained from the slope of the mass dissolved vs. time plots taken at early times, and volume normalized initial dissolution rates RV were calculated by dividing the initial dissolution rate by the volume fraction of the drug in the formulation. Comparison of the RV values for the various formulations with a reference RV (typically that of the pure drug or of the formulation with the highest polymer content) allowed calculation of relative volume normalized dissolution rates (RNV). The various RNV were used in the thermodynamic model for data analyses and to determine the interactions between the drug and carrier molecules. It was generally seen that RNV increased with decreased drug fraction, and was adequately modeled by the equations derived from the extended thermodynamic model. It was concluded that the model proposed for the binary and ternary systems successfully represented the mechanism of drug-polymer interaction and the energy changes taken place within the dispersion systems. The dissolution data analysis and subsequent understanding of physical modifications in the dispersion systems characterized by XRD, NIRS and DSC further substantiated the findings. The understanding of the fundamental physical might help scientists to predict the effects of mixing various drugs and polymers, and the effects of varying ratios.

Dynamics of altered surface layer formation on dissolving silicates

NASA Astrophysics Data System (ADS)

Daval, Damien; Bernard, Sylvain; Rémusat, Laurent; Wild, Bastien; Guyot, François; Micha, Jean Sébastien; Rieutord, François; Magnin, Valérie; Fernandez-Martinez, Alejandro

2017-07-01

The extrapolation of mineral dissolution kinetics experiments to geological timescales has frequently been challenged by the observation that mineral dissolution rates decrease with time. In the present study, we report a detailed investigation of the early stages of wollastonite dissolution kinetics, linking time-resolved measurements of wollastonite dissolution rate as a function of crystallographic orientation to the evolution of physicochemical properties (i.e., diffusivity, density, and thickness) of amorphous silica-rich layers (ASSLs) that developed on each surface. Batch dissolution experiments conducted at room temperature and at far-from-equilibrium conditions revealed that the initial (i.e., ASSL-free) dissolution rate of wollastonite (R(hkl)) based on Ca release observe the following trend: R(010) ≈R(100) >R(101) >R(001) . A gradual decrease of the dissolution rate of some faces by up to one order of magnitude resulted in a modification of this trend after two days: R(010) ≫R(100) ⩾R(101) ≈R(001) . In parallel, the diffusivity of ASSLs developed on each face was estimated based on the measurement of the concentration profile of a conservative tracer (methylene blue) across the ASSL using nanoSIMS. The apparent diffusion coefficients of methylene blue as a function of the crystallographic orientation (Dapp(hkl)) observe the following trend: Dapp(010) ⩾Dapp(100) >Dapp(101) ≫Dapp(001) , and decreases as a function of time for the (1 0 0) and (1 0 1) faces. Finally, the density of ASSL was estimated based on the modeling of X-ray reflectivity patterns acquired as a function of time. The density of ASSLs developed on the (0 1 0) faces remains low and constant, whereas it increases for the ASSLs developed on the (0 0 1) faces. On the whole, our results suggest that the impact of the formation of ASSLs on the wollastonite dissolution rate is anisotropic: while some crystal faces are weakly affected by the formation of non-passivating ASSLs (e.g., the (0 1 0) face), the dissolution of other faces is hampered by passivating ASSLs within a few hours. The observed passivation is suggested to originate from the progressive densification of the ASSL, which limits the transport of reactive species from and to the dissolving wollastonite surface, as evidenced by the estimated diffusivity of the ASSLs. Because the apparent face-specific diffusivity of the ASSLs is correlated with the face-specific initial (i.e., ASSL-free) dissolution rate of wollastonite, we propose that the extent of ASSL densification (and the resulting impact on ion transport) is (at least partly) controlled by the absolute mineral dissolution rate. Overall, this study argues that the formation and microstructural evolution of ASSLs are likely candidates for mineral ageing, highlighting the need for determining the parameters controlling the spontaneous changes of ASSL diffusivity as a function of the reaction progress.

CHANGES IN TERRESTRIAL ECOLOGY RELATED TO A COAL-FIRED POWER PLANT: WISCONSIN POWER PLANT IMPACT STUDY

EPA Science Inventory

This report summarizes the effects of a coal-fired power plant on terrestrial plants and animals. Research was conducted from 1971 through 1977 at the Columbia Generating Station in the eastern flood-plain of the Wisconsin River in south-central Wisconsin. Initial studies were la...

30 CFR 730.11 - Inconsistent and more stringent State laws and regulations.

Code of Federal Regulations, 2010 CFR

2010-07-01

... regulations. 730.11 Section 730.11 Mineral Resources OFFICE OF SURFACE MINING RECLAMATION AND ENFORCEMENT... Register setting forth the text or a summary of any State law or regulation initially determined by him to... stringent land use and environmental controls and regulations of coal exploration and surface coal mining...

Strength Restoration of Cracked Sandstone and Coal under a Uniaxial Compression Test and Correlated Damage Source Location Based on Acoustic Emissions.

PubMed

Feng, Xiaowei; Zhang, Nong; Zheng, Xigui; Pan, Dongjiang

2015-01-01

Underground rock masses have shown a general trend of natural balance over billions of years of ground movement. Nonetheless, man-made underground constructions disturb this balance and cause rock stability failure. Fractured rock masses are frequently encountered in underground constructions, and this study aims to restore the strength of rock masses that have experienced considerable fracturing under uniaxial compression. Coal and sandstone from a deep-buried coal mine were chosen as experimental subjects; they were crushed by uniaxial compression and then carefully restored by a chemical adhesive called MEYCO 364 with an innovative self-made device. Finally, the restored specimens were crushed once again by uniaxial compression. Axial stress, axial strain, circumferential strain, and volumetric strain data for the entire process were fully captured and are discussed here. An acoustic emission (AE) testing system was adopted to cooperate with the uniaxial compression system to provide better definitions for crack closure thresholds, crack initiation thresholds, crack damage thresholds, and three-dimensional damage source locations in intact and restored specimens. Several remarkable findings were obtained. The restoration effects of coal are considerably better than those of sandstone because the strength recovery coefficient of the former is 1.20, whereas that of the latter is 0.33, which indicates that MEYCO 364 is particularly valid for fractured rocks whose initial intact peak stress is less than that of MEYCO 364. Secondary cracked traces of restored sandstone almost follow the cracked traces of the initial intact sandstone, and the final failure is mainly caused by decoupling between the adhesive and the rock mass. However, cracked traces of restored coal only partially follow the traces of intact coal, with the final failure of the restored coal being caused by both bonding interface decoupling and self-breakage in coal. Three-dimensional damage source locations manifest such that AE events are highly correlated with a strength recovery coefficient; the AE events show a decreasing tendency when the coefficient is larger than 1, and vice versa. This study provides a feasible scheme for the reinforcement of fractured rock masses in underground constructions and reveals an internal mechanism of the crushing process for restored rock masses, which has certain instructive significance.

Strength Restoration of Cracked Sandstone and Coal under a Uniaxial Compression Test and Correlated Damage Source Location Based on Acoustic Emissions

PubMed Central

Feng, Xiaowei; Zhang, Nong; Zheng, Xigui; Pan, Dongjiang

2015-01-01

Underground rock masses have shown a general trend of natural balance over billions of years of ground movement. Nonetheless, man-made underground constructions disturb this balance and cause rock stability failure. Fractured rock masses are frequently encountered in underground constructions, and this study aims to restore the strength of rock masses that have experienced considerable fracturing under uniaxial compression. Coal and sandstone from a deep-buried coal mine were chosen as experimental subjects; they were crushed by uniaxial compression and then carefully restored by a chemical adhesive called MEYCO 364 with an innovative self-made device. Finally, the restored specimens were crushed once again by uniaxial compression. Axial stress, axial strain, circumferential strain, and volumetric strain data for the entire process were fully captured and are discussed here. An acoustic emission (AE) testing system was adopted to cooperate with the uniaxial compression system to provide better definitions for crack closure thresholds, crack initiation thresholds, crack damage thresholds, and three-dimensional damage source locations in intact and restored specimens. Several remarkable findings were obtained. The restoration effects of coal are considerably better than those of sandstone because the strength recovery coefficient of the former is 1.20, whereas that of the latter is 0.33, which indicates that MEYCO 364 is particularly valid for fractured rocks whose initial intact peak stress is less than that of MEYCO 364. Secondary cracked traces of restored sandstone almost follow the cracked traces of the initial intact sandstone, and the final failure is mainly caused by decoupling between the adhesive and the rock mass. However, cracked traces of restored coal only partially follow the traces of intact coal, with the final failure of the restored coal being caused by both bonding interface decoupling and self-breakage in coal. Three-dimensional damage source locations manifest such that AE events are highly correlated with a strength recovery coefficient; the AE events show a decreasing tendency when the coefficient is larger than 1, and vice versa. This study provides a feasible scheme for the reinforcement of fractured rock masses in underground constructions and reveals an internal mechanism of the crushing process for restored rock masses, which has certain instructive significance. PMID:26714324

National Coal Utilization Assessment. a preliminary assessment of the health and environmental effects of coal utilization in the Midwest. Volume I. Energy scenarios, technology characterizations, air and water resource impacts, and health effects

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1977-01-01

This report presents an initial evaluation of the major health and environmental issues associated with increased coal use in the six midwestern states of Illinois, Indiana, Michigan, Minnesota, Ohio, and Wisconsin. Using an integrated assessment approach, the evaluation proceeds from a base-line scenario of energy demand and facility siting for 1975-2020. Emphasis is placed on impacts from coal extraction, land reclamation, coal combustion for electrical generation, and coal gasification. The range of potential impacts and constraints is illustrated by a second scenario that represents an expected upper limit for coal utilization in Illinois. The following are among the more significantmore » issues identified and evaluated in this study: If environmental and related issues can be resolved, coal will continue to be a major source of energy for the Midwest; existing sulfur emission constraints will increase use of western coal; the resource requirements and environmental impacts of coal utilization will require major significant environmental and economic tradeoffs in site selection; short-term (24-hr) ambient standards for sulfur dioxide will limit the sizes of coal facilities or require advanced control technologies; an impact on public health may result from long-range transport of airborne sulfur emissions from coal facilities in the Midwest; inadequately controlled effluents from coal gasification may cause violations of water-quality standards; the major ecological effects of coal extraction are from pre-mining and post-reclamation land use; and sulfur dioxide is the major potential contributor to effects on vegetation of atmospheric emissions from coal facilities.« less

Phase Behavior of Ritonavir Amorphous Solid Dispersions during Hydration and Dissolution.

PubMed

Purohit, Hitesh S; Taylor, Lynne S

2017-12-01

The aim of this research was to study the interplay of solid and solution state phase transformations during the dissolution of ritonavir (RTV) amorphous solid dispersions (ASDs). RTV ASDs with polyvinylpyrrolidone (PVP), polyvinylpyrrolidone vinyl acetate (PVPVA) and hydroxypropyl methylcellulose acetate succinate (HPMCAS) were prepared at 10-50% drug loading by solvent evaporation. The miscibility of RTV ASDs was studied before and after exposure to 97% relative humidity (RH). Non-sink dissolution studies were performed on fresh and moisture-exposed ASDs. RTV and polymer release were monitored using ultraviolet-visible spectroscopy. Techniques including fluorescence spectroscopy, confocal imaging, scanning electron microscopy (SEM), atomic force microscopy (AFM), differential scanning calorimetry (DSC) and nanoparticle tracking analysis (NTA) were utilized to monitor solid and the solution state phase transformations. All RTV-PVP and RTV-PVPVA ASDs underwent moisture-induced amorphous-amorphous phase separation (AAPS) on high RH storage whereas RTV-HPMCAS ASDs remained miscible. Non-sink dissolution of PVP- and PVPVA-based ASDs at low drug loadings led to rapid RTV and polymer release resulting in concentrations in excess of amorphous solubility, liquid-liquid phase separation (LLPS) and amorphous nanodroplet formation. High drug loading PVP- and PVPVA-based ASDs did not exhibit LLPS upon dissolution as a consequence of extensive AAPS in the hydrated ASD matrix. All RTV-HPMCAS ASDs led to LLPS upon dissolution. RTV ASD dissolution is governed by a competition between the dissolution rate and the rate of phase separation in the hydrated ASD matrix. LLPS was observed for ASDs where the drug release was polymer controlled and only ASDs that remained miscible during the initial phase of dissolution led to LLPS. Techniques such as fluorescence spectroscopy, confocal imaging and SEM were useful in understanding the phase behavior of ASDs upon hydration and dissolution and were helpful in elucidating the mechanism of generation of amorphous nanodroplets.

Dissolution Rates and Mineral Lifetimes of Phosphate Containing Minerals and Implications for Mars

NASA Astrophysics Data System (ADS)

Adcock, C. T.; Hausrath, E.

2011-12-01

The objectives of NASA's Mars Exploration Program include exploring the planet's habitability and the possibility of past, present, or future life. This includes investigating "possible supplies of bioessential elements" [1]. Phosphate is one such bioessential element for life as we understand it. Phosphate is also abundant on Mars [2], and the phosphate rich minerals chlorapatite, fluorapatite, and merrillite have been observed in Martian meteorites [3]. Surface rock analyses from the MER Spirit also show the loss of a phosphate rich mineral from the rocks Wishstone and Watchtower at Gusev Crater [4,5], implying mineral dissolution. Dissolution rates of phosphate containing minerals are therefore important for characterizing phosphate mobility and bioavailability on Mars. Previous studies have measured dissolution rates of fluorapatite [6-8]. However, chlorapatite and merrillite (a non-terrestrial mineral similar to whitlockite) are more common phosphate minerals found in Martian meteorites [3], and few dissolution data exist for these minerals. We have begun batch dissolution experiments on chlorapatite, synthesized using methods of [9], and whitlockite, synthesized using a method modified from [10]. Additionally, we are dissolving Durango fluorapatite to compare to dissolution rates in literature, and natural Palermo whitlockite to compare to dissolution rates of our synthesized whitlockite. Batch dissolution experiments were performed after [8], using a 0.01 molar KNO3 solution with 0.1500g-0.3000g mineral powders and starting solution volumes of 180ml in LDPE reaction vessels. HNO3 or KOH were used to adjust initial pH as required. Dissolution rates are calculated from the rate of change of elemental concentration in solution as a function of time, and normalized to the mineral surface area as measured by BET. Resulting rates will be used to calculate mineral lifetimes for the different phosphate minerals under potential Mars-like aqueous conditions, and in future reactive transport modeling.

Apparatus and method for direct measurement of coal ash sintering and fusion properties at elevated temperatures and pressures

DOEpatents

Khan, M. Rashid

1990-01-01

A high-pressure microdilatometer is provided for measuring the sintering and fusion properties of various coal ashes under the influence of elevated pressures and temperatures in various atmospheres. Electrical resistivity measurements across a sample of coal ash provide a measurement of the onset of the sintering and fusion of the ash particulates while the contraction of the sample during sintering is measured with a linear variable displacement transducer for detecting the initiation of sintering. These measurements of sintering in coal ash at different pressures provide a mechanism by which deleterious problems due to the sintering and fusion of ash in various combustion systems can be minimized or obviated.

Record production on Gary No. 13 blast furnace with 450 lb./THM co-injection rates

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schuett, K.J.; White, D.G.

1996-12-31

Coal injection was initiated on No. 13 Blast Furnace in 1993 with 400 lb/THM achieved in 9 months. In early 1994, cold weather and coal preparation upsets led to the use of a second injectant, oil atomized by natural gas, to supplement the coal. Various combinations of coal and oil were investigated as total injection was increased to 450 lb/THM. Beginning in the last half of 1994, a continuing effort has been made to increase furnace production while maintaining this high co-injection level. Typical furnace production is now in excess of 10,000 THM/day compared with about 8500 THM/day in latemore » 1993.« less

Differentiation of pre-existing trapped methane from thermogenic methane in an igneous-intruded coal by hydrous pyrolysis

USGS Publications Warehouse

Dias, Robert F.; Lewan, Michael D.; Birdwell, Justin E.; Kotarba, Maciej J.

2014-01-01

So as to better understand how the gas generation potential of coal changes with increasing rank, same-seam samples of bituminous coal from the Illinois Basin that were naturally matured to varying degrees by the intrusion of an igneous dike were subjected to hydrous pyrolysis (HP) conditions of 360 °C for 72 h. The accumulated methane in the reactor headspace was analyzed for δ13C and δ2H, and mol percent composition. Maximum methane production (9.7 mg/g TOC) occurred in the most immature samples (0.5 %Ro), waning to minimal methane values at 2.44 %Ro (0.67 mg/g TOC), and rebounding to 3.6 mg/g TOC methane in the most mature sample (6.76 %Ro). Methane from coal with the highest initial thermal maturity (6.76 %Ro) shows no isotopic dependence on the reactor water and has a microbial δ13C value of −61‰. However, methane from coal of minimal initial thermal maturity (0.5 %Ro) shows hydrogen isotopic dependence on the reaction water and has a δ13C value of −37‰. The gas released from coals under hydrous pyrolysis conditions represents a quantifiable mixture of ancient (270 Ma) methane (likely microbial) that was generated in situ and trapped within the rock during the rapid heating by the dike, and modern (laboratory) thermogenic methane that was generated from the indigenous organic matter due to thermal maturation induced by hydrous pyrolysis conditions. These findings provide an analytical framework for better assessment of natural gas sources and for differentiating generated gas from pre-existing trapped gas in coals of various ranks.

Capturing the emerging market for climate-friendly technologies: opportunities for Ohio

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

2006-11-15

This paper briefly describes the factors driving the growing demand for climate-friendly technologies, some of the key existing companies, organizations, and resources in Ohio, and the potential for Ohio to become a leading supplier of climate solutions. These solutions include a new generation of lower-emitting coal technologies, components for wind turbines, and the feedstocks and facilities to produce biofuels. Several public-private partnerships and initiatives have been established in Ohio. These efforts have encouraged the development of numerous federal- and state-funded projects and attracted major private investments in two increasingly strategic sectors of the Ohio economy: clean-coal technology and alternative energymore » technology, with a focus on fuel cells. Several major clean-coal projects have been recently initiated in Ohio. In April 2006, the Public Utilities Commission of Ohio approved American Electric Power's (AEP) plan to build a 600 MW clean-coal plant along the Ohio River in Meigs County. The plant will use Integrated Gasification Combined Cycle (IGCC) technology which makes it easier to capture carbon dioxide for sequestration. Three other potential coal gasification facilities are being considered in Ohio: a combination IGCC and synthetic natural gas plant in Allen County by Global Energy/Lima Energy; a coal-to-fuels facility in Lawrence County by Baard Energy, and a coal-to-fuels facility in Scioto County by CME North American Merchant Energy. The paper concludes with recommendations for how Ohio can capitalize on these emerging opportunities. These recommendations include focusing and coordinating state funding of climate technology programs, promoting the development of climate-related industry clusters, and exploring export opportunities to states and countries with existing carbon constraints.« less

Dissolution of fludrocortisone from phospholipid coprecipitates.

PubMed

Vudathala, G K; Rogers, J A

1992-03-01

The physical properties and dissolution behavior of phospholipid coprecipitates of fludrocortisone acetate (FA) prepared from ethyl acetate, as well as the effect of added polymer, have been determined. The fraction dissolved after 90 min and the initial dissolution rate (IDR) of coprecipitates containing dimyristoyl phosphatidylcholine (DMPC) (4:1, w/w; FA:DMPC) were 77% and 3.5-fold greater than for FA at pH 2.0 and 37 degrees C. The mechanisms of dissolution were similar to those previously established for griseofulvin, but no aging occurred over 4 months at room temperature in a desiccator. The addition of 0.01 mol% of dextran (MW = 2 million) or 0.1 mol% of poly(lactic acid) reduced the fraction of FA dissolved in 90 min by 15% and reduced the IDR by 35%. The addition of poly(vinylpyrrolidone) (PVP) resulted in a minimum of dissolution efficiency at 1 mol% of PVP 10 (MW = 10,000) or PVP 24 (MW = 24,000) and at 0.1 mol% PVP 40 (MW = 40,000). Only PVP 24 influenced the melting point and heat of fusion of the coprecipitates (determined by differential thermal analysis). Coprecipitate dissolution was reasonably described by either second-order or Weibull distribution kinetic models. These results support the application of high drug-containing solid dispersions using phospholipids to increase the dissolution behavior of poorly water-soluble drug solvates and the possibility of modifying drug release by the incorporation of small amounts of polymers.

Experimental investigation of the dissolution of fractures. From early stage instability to phase diagram

NASA Astrophysics Data System (ADS)

Osselin, Florian; Budek, Agnieszka; Cybulski, Olgierd; Kondratiuk, Pawel; Garstecki, Piotr; Szymczak, Piotr

2016-04-01

Dissolution of natural rocks is a fundamental geological process and a key part of landscape formation and weathering processes. Moreover, in current hot topics like Carbon Capture and Storage or Enhanced Oil Recovery, mastering dissolution of the host rock is fundamental for the efficiency and the security of the operation. The basic principles of dissolution are well-known and the theory of the reactive infiltration instability has been extensively studied. However, the experimental aspect has proved very challenging because of the strong dependence of the outcome with pore network, chemical composition, flow rate... In this study we are trying to tackle this issue by using a very simple and efficient device consisting of a chip of pure gypsum inserted between two polycarbonate plates and subjected to a constant flow rate of pure water. Thanks to this device, we are able to control all parameters such as flow rate, fracture aperture, roughness of the walls... but also to observe in situ the progression of the dissolution thanks to the transparency of the polycarbonate which is impossible with 3D rocks. We have been using this experimental set-up to explore and investigate all aspects of the dissolution in a fracture, such as initial instability and phase diagram of different dissolution patterns, and to compare it with theory and simulations, yielding very good agreement and interesting feedbacks on the coupling between flow and chemistry in geological media

Ionic solutions of two-dimensional materials

NASA Astrophysics Data System (ADS)

Cullen, Patrick L.; Cox, Kathleen M.; Bin Subhan, Mohammed K.; Picco, Loren; Payton, Oliver D.; Buckley, David J.; Miller, Thomas S.; Hodge, Stephen A.; Skipper, Neal T.; Tileli, Vasiliki; Howard, Christopher A.

2017-03-01

Strategies for forming liquid dispersions of nanomaterials typically focus on retarding reaggregation, for example via surface modification, as opposed to promoting the thermodynamically driven dissolution common for molecule-sized species. Here we demonstrate the true dissolution of a wide range of important 2D nanomaterials by forming layered material salts that spontaneously dissolve in polar solvents yielding ionic solutions. The benign dissolution advantageously maintains the morphology of the starting material, is stable against reaggregation and can achieve solutions containing exclusively individualized monolayers. Importantly, the charge on the anionic nanosheet solutes is reversible, enables targeted deposition over large areas via electroplating and can initiate novel self-assembly upon drying. Our findings thus reveal a unique solution-like behaviour for 2D materials that enables their scalable production and controlled manipulation.

The effect of ion irradiation on the dissolution of UO 2 and UO 2 -based simulant fuel

DOE PAGES

Popel, Aleksej J.; Wietsma, Thomas W.; Engelhard, Mark H.; ...

2017-11-21

Our aim is to study the separate effect of fission fragment damage on the dissolution of simulant UK advanced gas-cooled reactor nuclear fuel in water. Plain UO 2 and UO 2 samples, doped with inactive fission products to simulate 43 GWd/tU of burn-up, were fabricated. A set of these samples were then irradiated with 92 MeV 129Xe 23+ ions to a fluence of 4.8 × 10 15 ions/cm 2 to simulate the fission damage that occurs within nuclear fuels. The primary effect of the irradiation on the UO 2 samples, observed by scanning electron microscopy, was to induce a smootheningmore » of the surface features and formation of hollow blisters, which was attributed to multiple overlap of ion tracks. Dissolution experiments were conducted in single-pass flow-through (SPFT) mode under anoxic conditions (<0.1 O 2 ppm in Ar) to study the effect of the induced irradiation damage on the dissolution of the UO 2 matrix with data collection capturing six minute intervals for several hours. These time-resolved data showed that the irradiated samples showed a higher initial release of uranium than unirradiated samples, but that the uranium concentrations converged towards ~10 -9 mol/l after a few hours. And apart from the initial spike in uranium concentration, attributed to irradiation induced surficial micro-structural changes, no noticeable difference in uranium chemistry as measured by X-ray electron spectroscopy or ‘effective solubility’ was observed between the irradiated, doped and undoped samples in this work. Some secondary phase formation was observed on the surface of UO 2 samples after the dissolution experiment.« less

The effect of ion irradiation on the dissolution of UO 2 and UO 2 -based simulant fuel

DOE Office of Scientific and Technical Information (OSTI.GOV)

Popel, Aleksej J.; Wietsma, Thomas W.; Engelhard, Mark H.

Our aim is to study the separate effect of fission fragment damage on the dissolution of simulant UK advanced gas-cooled reactor nuclear fuel in water. Plain UO 2 and UO 2 samples, doped with inactive fission products to simulate 43 GWd/tU of burn-up, were fabricated. A set of these samples were then irradiated with 92 MeV 129Xe 23+ ions to a fluence of 4.8 × 10 15 ions/cm 2 to simulate the fission damage that occurs within nuclear fuels. The primary effect of the irradiation on the UO 2 samples, observed by scanning electron microscopy, was to induce a smootheningmore » of the surface features and formation of hollow blisters, which was attributed to multiple overlap of ion tracks. Dissolution experiments were conducted in single-pass flow-through (SPFT) mode under anoxic conditions (<0.1 O 2 ppm in Ar) to study the effect of the induced irradiation damage on the dissolution of the UO 2 matrix with data collection capturing six minute intervals for several hours. These time-resolved data showed that the irradiated samples showed a higher initial release of uranium than unirradiated samples, but that the uranium concentrations converged towards ~10 -9 mol/l after a few hours. And apart from the initial spike in uranium concentration, attributed to irradiation induced surficial micro-structural changes, no noticeable difference in uranium chemistry as measured by X-ray electron spectroscopy or ‘effective solubility’ was observed between the irradiated, doped and undoped samples in this work. Some secondary phase formation was observed on the surface of UO 2 samples after the dissolution experiment.« less

Tissue dissolution ability of sodium hypochlorite activated by photon-initiated photoacoustic streaming technique.

PubMed

Guneser, Mehmet Burak; Arslan, Dilara; Usumez, Aslihan

2015-05-01

The aim of this study was to evaluate the effect of the photon-initiated photoacoustic streaming (PIPS) technique on the pulp tissue-dissolving capacity of sodium hypochlorite (NaOCl) and compare it with the EndoActivator System (Dentsply Tulsa Dental Specialties, Tulsa, OK) and the Er:YAG laser with an endodontic fiber tip. Bovine pulp tissue samples (45 ± 15 mg) and dentin powder (10 mg) were placed in 1.5-mL Eppendorf tubes with 1 mL 5.25% NaOCl (Wizard; Rehber Kimya, Istanbul, Turkey) or distilled water (control) for 5 minutes with activation by the EndoActivator System, the Er:YAG laser with an endodontic fiber tip, and the PIPS technique. Nonactivated NaOCl served as the positive control. All testing procedures were performed at room temperature. The tissue samples were weighed before and after treatment, and the percentage of weight loss was calculated. The differences were statistically analyzed. The highest rate of tissue dissolution was observed in the NaOCl + Er:YAG group (P < .05). The NaOCl + PIPS group dissolved more bovine pulp tissue than the nonactivated NaOCl group (P < .05). There was no statistically significant difference between the rates of tissue dissolution of the NaOCl + EA and the nonactivated NaOCl groups (P > .05). NaOCl activation with the Er:YAG laser with an endodontic fiber tip was the most effective in bovine pulp tissue dissolution. The PIPS technique also promoted superior tissue-dissolving effects when compared with no activation. However, the EndoActivator System had no direct effect on tissue dissolution. Copyright © 2015 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Underground Coal Gasification Research Program near Hanna, Carbon County, Wyoming: Environmental impact assessment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

In the fall of 1972, the Laramie Energy Research Center initiated an in situ coal gasification experiment in Hanna, Wyoming. The objective was to test the feasibility of underground gasification in a deep, thick seam of western subbituminous coal and, if feasible, to maximize gas heating value while sustaining stable gas production rates and achieving a high coal utilization efficiency. The coal seam was ignited on March 28, 1973, in a 30-foot seam 400 feet deep. The ''burn'' was maintained for a year, until March 22, 1974, when air injection was stopped. The combustion zone was extinguished by the naturalmore » influx of seam water in approximately three months. This report discusses the environmental inpacts of this program on the area and provides details of the program. 13 refs., 7 figs., 11 tabs.« less

Studying the specific features pertinent to combustion of chars obtained from coals having different degrees of metamorphism and biomass chars

NASA Astrophysics Data System (ADS)

Bestsennyi, I. V.; Shchudlo, T. S.; Dunaevskaya, N. I.; Topal, A. I.

2013-12-01

Better conditions for igniting low-reaction coal (anthracite) can be obtained, higher fuel burnout ratio can be achieved, and the problem of shortage of a certain grade of coal can be solved by firing coal mixtures and by combusting coal jointly with solid biomass in coal-fired boilers. Results from studying the synergetic effect that had been revealed previously during the combustion of coal mixtures in flames are presented. A similar effect was also obtained during joint combustion of coal and wood in a flame. The kinetics pertinent to combustion of char mixtures obtained from coals characterized by different degrees of metamorphism and the kinetics pertinent to combustion of wood chars were studied on the RSK-1D laboratory setup. It was found from the experiments that the combustion rate of char mixtures obtained from coals having close degrees of metamorphism is equal to the value determined as a weighted mean rate with respect to the content of carbon. The combustion rate of char mixtures obtained from coals having essentially different degrees of metamorphism is close to the combustion rate of more reactive coal initially in the process and to the combustion rate of less reactive coal at the end of the process. A dependence of the specific burnout rate of carbon contained in the char of two wood fractions on reciprocal temperature in the range 663—833 K is obtained. The combustion mode of an experimental sample is determined together with the reaction rate constant and activation energy.

Coal fly ash as a source of iron in atmospheric dust.

PubMed

Chen, Haihan; Laskin, Alexander; Baltrusaitis, Jonas; Gorski, Christopher A; Scherer, Michelle M; Grassian, Vicki H

2012-02-21

Anthropogenic coal fly ash (FA) aerosol may represent a significant source of bioavailable iron in the open ocean. Few measurements have been made that compare the solubility of atmospheric iron from anthropogenic aerosols and other sources. We report here an investigation of iron dissolution for three FA samples in acidic aqueous solutions and compare the solubilities with that of Arizona test dust (AZTD), a reference material for mineral dust. The effects of pH, simulated cloud processing, and solar radiation on iron solubility have been explored. Similar to previously reported results on mineral dust, iron in aluminosilicate phases provides the predominant component of dissolved iron. Iron solubility of FA is substantially higher than of the crystalline minerals comprising AZTD. Simulated atmospheric processing elevates iron solubility due to significant changes in the morphology of aluminosilicate glass, a dominant material in FA particles. Iron is continuously released into the aqueous solution as FA particles break up into smaller fragments. These results suggest that the assessment of dissolved atmospheric iron deposition fluxes and their effect on the biogeochemistry at the ocean surface should be constrained by the source, environmental pH, iron speciation, and solar radiation.

Advanced direct coal liquefaction concepts. Quarterly report, January 1, 1994--March 31, 1994

DOE Office of Scientific and Technical Information (OSTI.GOV)

Berger, D.J.; Parker, R.J.; Simpson, P.L.

A detailed evaluation of the bench unit data on Black Thunder feedstocks was completed. The results show that in a once-through operation using counterflow, reactor technology coal conversions in excess of 90% could be obtained, giving distillable oil yields in the range 60--65 wt % on MAF coal. The remaining non-distillable oil fraction which represents 20--25 wt % on MAF coal is a source of additional distillable oil in further processing, for example, bottoms recycle operation. C{sub 1}-C{sub 3} gas yields were generally in the order of 6--8 wt %. In autoclave studies, Illinois No. 6 coal was found tomore » be much less reactive than Black Thunder coal, and did not respond well to solubilization with carbon monoxide/steam. Process severity was, therefore, increased for bench unit operations on Illinois No. 6 coal, and work has concentrated on the use of hydrogen rather than carbon monoxide for solubilization. Preliminary coking studies on the resid from bench unit runs on Black Thunder coal were also carried out. Distillable liquid yields of 55--60 wt % were obtained. The technical and economic study to be carried out by Kilborn Engineering Company has been initiated.« less

Pilot-Scale Demonstration of Pefi's Oxygenated Transportation Fuels Production Technology

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

Coal-cleaning processes have been utilized to increase the heating value of coal by extracting ash-forming minerals in the coal. These processes involve the crushing or grinding of raw coal followed by physical separation processes, taking advantage of the density difference between carbonaceous particles and mineral particles. In addition to the desired increase in the heating value of coal, a significant reduction of the sulfur content of the coal fed to a combustion unit is effected by the removal of pyrite and other sulfides found in the mineral matter. WRI is assisting PulseWave to develop an alternate, more efficient method ofmore » liberating and separating the undesirable mineral matter from the carbonaceous matter in coal. The approach is based on PulseWave's patented resonance disintegration technology that reduces that particle size of materials by application of destructive resonance, shock waves, and vortex generating forces. Illinois No.5 coal, a Wyodak coal, and a Pittsburgh No.8 coal were processed using the resonance disintegration apparatus then subjected to conventional density separations. Initial microscopic results indicate that up to 90% of the pyrite could be liberated from the coal in the machine, but limitations in the density separations reduced overall effectiveness of contaminant removal. Approximately 30-80% of the pyritic sulfur and 30-50% of the mercury was removed from the coal. The three coals (both with and without the pyritic phase separated out) were tested in WRI's 250,000 Btu/hr Combustion Test Facility, designed to replicate a coal-fired utility boiler. The flue gases were characterized for elemental, particle bound, and total mercury in addition to sulfur. The results indicated that pre-combustion cleaning could reduce a large fraction of the mercury emissions.« less

Geochemical Analyses of Surface and Shallow Gas Flux and Composition Over a Proposed Carbon Sequestration Site in Eastern Kentucky

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thomas Parris; Michael Solis; Kathryn Takacs

2009-12-31

Using soil gas chemistry to detect leakage from underground reservoirs (i.e. microseepage) requires that the natural range of soil gas flux and chemistry be fully characterized. To meet this need, soil gas flux (CO{sub 2}, CH{sub 4}) and the bulk (CO{sub 2}, CH{sub 4}) and isotopic chemistry ({delta}{sup 13}C-CO2) of shallow soil gases (<1 m, 3.3 ft) were measured at 25 locations distributed among two active oil and gas fields, an active strip mine, and a relatively undisturbed research forest in eastern Kentucky. The measurements apportion the biologic, atmospheric, and geologic influences on soil gas composition under varying degrees ofmore » human surface disturbance. The measurements also highlight potential challenges in using soil gas chemistry as a monitoring tool where the surface cover consists of reclaimed mine land or is underlain by shallow coals. For example, enrichment of ({delta}{sup 13}C-CO2) and high CH{sub 4} concentrations in soils have been historically used as indicators of microseepage, but in the reclaimed mine lands similar soil chemistry characteristics likely result from dissolution of carbonate cement in siliciclastic clasts having {delta}{sup 13}C values close to 0{per_thousand} and degassing of coal fragments. The gases accumulate in the reclaimed mine land soils because intense compaction reduces soil permeability, thereby impeding equilibration with the atmosphere. Consequently, the reclaimed mine lands provide a false microseepage anomaly. Further potential challenges arise from low permeability zones associated with compacted soils in reclaimed mine lands and shallow coals in undisturbed areas that might impede upward gas migration. To investigate the effect of these materials on gas migration and composition, four 10 m (33 ft) deep monitoring wells were drilled in reclaimed mine material and in undisturbed soils with and without coals. The wells, configured with sampling zones at discrete intervals, show the persistence of some of the aforementioned anomalies at depth. Moreover, high CO{sub 2} concentrations associated with coals in the vadose zone suggest a strong affinity for adsorbing CO{sub 2}. Overall, the low permeability of reclaimed mine lands and coals and CO2 adsorption by the latter is likely to reduce the ability of surface geochemistry tools to detect a microseepage signal.« less

Experimental laboratory measurement of thermophysical properties of selected coal types

NASA Technical Reports Server (NTRS)

Lloyd, W. G.

1979-01-01

A number of bituminous coals of moderate to high plasticity were examined, along with portions of their extrudates from the JPL 1.5-inch 850 F screw extruder. Portions of the condensed pyrolysis liquids released during extrusion, and of the gaseous products formed during extrusion were also analyzed. In addition to the traditional determinations, the coals and extrudates were examined in terms of microstructure (especially extractable fractions), thermal analysis (especially that associated with the plastic state), and reactivity towards thermal and catalyzed hydroliquefaction. The process of extrusion increases the fixed carbon content of coals by about 5% and tends to increase the surface area. Coals contaning 25% or more DMF-extractable material show an increase in extractables as a result of extrusion; those initially containing less than 20% extractables show a decrease as a result of extrusion. Both the raw and extruded samples of Kentucky #9 coal are highly reactive towards hydroliquefaction, undergoing conversions of 75 to 80% in 15 min and 85-94% in 60 min in a stirred clave.

Oxidation and carbonisation of coals: a case study of coal fire affected coals from the Wuda coalfield, Inner Mongolia, China

NASA Astrophysics Data System (ADS)

Kus, Jolanta; Meyer, Uwe; Ma, Jianwei; Chen-Brauchler, Dai

2010-05-01

At the coalfield of Wuda (Inner Mongolia, PR China) extensive underground coal fires cause widespread thermal and oxidative effects in coal seams. Within phase B of the Coal Fire Research Project of the Sino-German Initiative, methods for innovative fire-extinguishing technologies were investigated in multifaceted research approaches. Extensive investigations of oxidative and thermally affected coal seams in coal fire zone 18 were conducted in 2008 prior to application of new fire-extinguishing methods. We present results from the outcrop of coal seam No. 4 in the fire zone 18. The coal of seam No. 4 is of Early Permian age and belongs stratigraphically to the Shanxi Formation. The unaffected coal displays a high volatile bituminous A rank with a background value of random vitrinite reflectance ranging from 0.90 to 0.96 % Rr. Coal channel samples were coallected at actively extracted coal faces along multiple profiles with surface temperatures ranging from about 50° to 600°C. Microscopic examinations revealed a variety of products of coal exposure to the fire. Within coal samples, a marked rise in vitrinite reflectance from background values to 5.55% Rr (6.00 % Rmax) is encountered. In addition, a number of coal samples showed suppressed vitrinite reflectances ranging between 0.82 to 0.88% Rr. Further, seemingly heat unaffected coal samples display intensive development of oxidations rims at coal grain edges and cracks as well as shrinkage cracks and formation of iron oxides/hydroxides. Instead, thermally affected coal samples with higher coalification grade are further characterised by development of macropores (devolatilisation pores) in vitrinitic streaks, transformation of liptinite to meta-liptinite and micrinite as well as by natural coke particles of mostly porous nature and fine to coarse grained anisotropic mosaic. Coal petrographic investigations confirmed a hypothesis that both, oxidations as well as low temperature carbonisation govern the thermal regime in the coal fire zone 18. The occurrence of various thermal alteration products indicates temperatures in the range of 500-700°C.

Understanding the roles of ligand promoted dissolution, water column saturation and hydrological properties on intense basalt weathering using reactive transport and watershed-scale hydrologic modeling

NASA Astrophysics Data System (ADS)

Perez Fodich, A.; Walter, M. T.; Derry, L. A.

2016-12-01

The interaction of rocks with rainwater generates physical and chemical changes, which ultimately culminates in soil development. The addition of catalyzers such as plants, atmospheric gases and hydrological properties will result in more intense and/or faster weathering transformations. The intensity of weathering across the Island of Hawaii is strongly correlated with exposure age and time-integrated precipitation. Intense weathering has resulted from interaction between a thermodynamically unstable lithology, high water/rock ratios, atmospheric gases (O2, CO2) and biota as an organic acid and CO2 producer. To further investigate the role of different weathering agents we have developed 1-D reactive transport models (RTM) to understand mineralogical and fluid chemistry changes in the initially basaltic porous media. The initial meso-scale heterogeneity of porosity makes it difficult for RTMs to capture changes in runoff/groundwater partitioning. Therefore, hydraulic properties (hydraulic conductivity and aquifer depth) are modeled as a watershed parameter appropriate for this system where sub-surface hydraulic data is scarce(1). Initial results agree with field data in a broad sense: different rainfall regimes and timescales show depletion of mobile cations, increasingly low pH, congruent dissolution of olivine and pyroxene, incongruent dissolution of plagioclase and basaltic glass, precipitation of non-crystalline allophane and ferrihydrite, and porosity changes due to dissolution and precipitation of minerals; ultimately Al and Fe are also exported from the system. RTM is used to examine the roles of unsaturation in the soil profile, ligand promoted dissolution of Al- and Fe-bearing phases, and Fe-oxide precipitation at the outcrop scale. Also, we aim to test the use of recession flow analysis to model watershed-scale hydrological properties to extrapolate changes in the runoff/groundwater partitioning. The coupling between weathering processes and hydrologic properties is a fundamental driver of the evolution of volcanic landscapes and weathering fluxes. 1. G. F. Mendoza, T. S. Steenhuis, M. T. Walter, J. Y. Parlange, Estimating basin-wide hydraulic parameters of a semi-arid mountainous watershed by recession-flow analysis. Journal of Hydrology 279, 57-69 (2003).

Shrub and tree establishment on coal spoils in northern High Plains - USA

Treesearch

Ardell J. Bjugstad

1984-01-01

Trickle irrigation, during establishment, increased survival two fold for seven species of shrubs and trees planted on coal mine spoil in the semiarid area of northeastern Wyoming, USA. Increased survival of irrigated plants persisted for five years after initiation of this study, which included two growing and winter seasons after cessation of irrigation. Species...

The influence of pH on biotite dissolution and alteration kinetics at low temperature

USGS Publications Warehouse

Acker, James G.; Bricker, O.P.

1992-01-01

Biotite dissolution rates in acidic solutions were determined in fluidized-bed reactors and flowthrough columns. Biotite dissolution rates increased inversely as a linear function of pH in the pH range 3-7, where the rate order n = -0.34. Biotite dissolved incongruently over this pH range, with preferential release of magnesium and iron from the octahedral layer. Release of tetrahedral silicon was much greater at pH 3 than at higher pH. Iron release was significantly enhanced by low pH conditions. Solution compositions from a continuous exposure flow-through column of biotite indicated biotite dissolves incongruently at pH 4, consistent with alteration to a vermiculite-type product. Solution compositions from a second intermittent-flow column exhibited elevated cation release rates upon the initiation of each exposure to solution. The presence of strong oxidizing agents, the mineral surface area, and sample preparation methodology also influenced the dissolution or alteration kinetics of biotite. ?? 1992.

Size-dependent reactivity of magnetite nanoparticles: a field-laboratory comparison

USGS Publications Warehouse

Swindle, Andrew L.; Elwood Madden, Andrew S.; Cozzarelli, Isabelle M.; Benamara, Mourad

2014-01-01

Logistic challenges make direct comparisons between laboratory- and field-based investigations into the size-dependent reactivity of nanomaterials difficult. This investigation sought to compare the size-dependent reactivity of nanoparticles in a field setting to a laboratory analog using the specific example of magnetite dissolution. Synthetic magnetite nanoparticles of three size intervals, ∼6 nm, ∼44 nm, and ∼90 nm were emplaced in the subsurface of the USGS research site at the Norman Landfill for up to 30 days using custom-made subsurface nanoparticle holders. Laboratory analog dissolution experiments were conducted using synthetic groundwater. Reaction products were analyzed via TEM and SEM and compared to initial particle characterizations. Field results indicated that an organic coating developed on the particle surfaces largely inhibiting reactivity. Limited dissolution occurred, with the amount of dissolution decreasing as particle size decreased. Conversely, the laboratory analogs without organics revealed greater dissolution of the smaller particles. These results showed that the presence of dissolved organics led to a nearly complete reversal in the size-dependent reactivity trends displayed between the field and laboratory experiments indicating that size-dependent trends observed in laboratory investigations may not be relevant in organic-rich natural systems.

Systematic review: Coca-Cola can effectively dissolve gastric phytobezoars as a first-line treatment.

PubMed

Ladas, S D; Kamberoglou, D; Karamanolis, G; Vlachogiannakos, J; Zouboulis-Vafiadis, I

2013-01-01

Gastric phytobezoars represent the most common bezoars in patients with poor gastric motility. A variety of dissolution therapies and endoscopic fragmentation techniques have been evaluated as conservative treatment so as to avoid surgery. To investigate the effectiveness of Coca-Cola for gastric phytobezoars dissolution. We performed a systematic search to identify publications on gastric phytobezoars to assess the efficacy of Coca-Cola as a dissolution therapy. Diospyrobezoars, formed after persimmon ingestion, are a distinct type of phytobezoars characterized by their hard consistency. Thus, these two subgroups of bezoars were compared in terms of successful dissolution. Over a 10-year period (2002-2012), 24 papers including 46 patients have been published. In 91.3% of the cases, phytobezoar resolution with Coca-Cola administration was successful, either as a single treatment (50%) or combined with further endoscopic techniques, whereas only 4 patients underwent surgery. Phytobezoars were more likely to dissolve after initial attempt with Coca-Cola compared with diospyrobezoars (60.6% vs. 23%, P = 0.022). Coca-Cola alone is effective in gastric phytobezoar dissolution in half of the cases and, combined with additional endoscopic methods, is successful in more than 90% of them. © 2012 Blackwell Publishing Ltd.

In vitro dissolution of uranium oxide by baboon alveolar macrophages.

PubMed Central

Poncy, J L; Metivier, H; Dhilly, M; Verry, M; Masse, R

1992-01-01

In vitro cellular dissolution tests for insoluble forms of uranium oxide are technically difficult with conventional methodology using adherent alveolar macrophages. The limited number of cells per flask and the slow dissolution rate in a large volume of nutritive medium are obvious restricting factors. Macrophages in suspension cannot be substituted because they represent different and poorly reproducible functional subtypes with regard to activation and enzyme secretion. Preliminary results on the dissolution of uranium oxide using immobilized alveolar macrophages are promising because large numbers of highly functional macrophages can be cultured in a limited volume. Cells were obtained by bronchoalveolar lavages performed on baboons (Papio papio) and then immobilized after the phagocytosis of uranium octoxide (U3O8) particles in alginate beads linked with Ca2+. The dissolution rate expressed as percentage of initial uranium content in cells was 0.039 +/- 0.016%/day for particles with a count median geometric diameter of 3.84 microns(sigma g = 1.84). A 2-fold increase in the dissolution rate was observed when the same number of particles was immobilized without macrophages. These results, obtained in vitro, suggest that the U3O8 preparation investigated should be assigned to inhalation class Y as recommended by the International Commission on Radiological Protection. Future experiments are intended to clarify this preliminary work and to examine the dissolution characteristics of other particles such as uranium dioxide. It is recommended that the dissolution rate should be measured over an interval of 3 weeks, which is compatible with the survival time of immobilized cells in culture and may reveal transformation states occurring with aging of the particles. PMID:1396447

Solutal Convection in Porous Media

NASA Astrophysics Data System (ADS)

Liang, Y.; Wen, B.; DiCarlo, D. A.; Hesse, M. A.

2017-12-01

Atmospheric CO2 is one important component of greenhouse gases, which can greatly affect the temperature of the Earth. There are four trapping mechanisms for CO2sequestration, including structural & stratigraphic trapping, residual trapping, dissolution trapping and mineral trapping. Leakage potential is a serious problem for its storage efficiency, and dissolution trapping is a method that can prevent such leakages effectively. Convective dissolution trapping process can be simplified to an interesting physical problem: in porous media, dissolution can initiate convection, and then its dynamics can be affected by the continuous convection conversely. However, it is difficult to detect whether the convective dissolution may take place, as well as how fast and in what pattern it may take place. Previous studies have established a model and related scaling (Rayleigh number and Sherwood number) to describe this physical problem. To testify this model with a large range of Rayleigh numbers, we conducted a series of convective dissolution experiments in porous media. In addition, this large experimental assembly can allow us to quantify relation between wavenumber of the convective motion and the controlling factors of the system for the first time. The result of our laboratory experiments are revolutionary: On one hand, it shows that previous scaling of the convective dissolution becomes invalid once the permeability is large enough; On the other hand, the relation between wavenumber and Rayleigh number demonstrates an opposite trend against the classic model. According to our experimental results, we propose a new model to describe the solutal convection in porous media, and our model can describe and explain our experimental observations. Also, simulation work has been conducted to confirm our model. In the future, our model and relevant knowledge can be unscaled to industrial applications which are relevant to convective dissolution process.

Evaluating the reliability of equilibrium dissolution assumption from residual gasoline in contact with water saturated sands

NASA Astrophysics Data System (ADS)

Lekmine, Greg; Sookhak Lari, Kaveh; Johnston, Colin D.; Bastow, Trevor P.; Rayner, John L.; Davis, Greg B.

2017-01-01

Understanding dissolution dynamics of hazardous compounds from complex gasoline mixtures is a key to long-term predictions of groundwater risks. The aim of this study was to investigate if the local equilibrium assumption for BTEX and TMBs (trimethylbenzenes) dissolution was valid under variable saturation in two dimensional flow conditions and evaluate the impact of local heterogeneities when equilibrium is verified at the scale of investigation. An initial residual gasoline saturation was established over the upper two-thirds of a water saturated sand pack. A constant horizontal pore velocity was maintained and water samples were recovered across 38 sampling ports over 141 days. Inside the residual NAPL zone, BTEX and TMBs dissolution curves were in agreement with the TMVOC model based on the local equilibrium assumption. Results compared to previous numerical studies suggest the presence of small scale dissolution fingering created perpendicular to the horizontal dissolution front, mainly triggered by heterogeneities in the medium structure and the local NAPL residual saturation. In the transition zone, TMVOC was able to represent a range of behaviours exhibited by the data, confirming equilibrium or near-equilibrium dissolution at the scale of investigation. The model locally showed discrepancies with the most soluble compounds, i.e. benzene and toluene, due to local heterogeneities exhibiting that at lower scale flow bypassing and channelling may have occurred. In these conditions mass transfer rates were still high enough to fall under the equilibrium assumption in TMVOC at the scale of investigation. Comparisons with other models involving upscaled mass transfer rates demonstrated that such approximations with TMVOC could lead to overestimate BTEX dissolution rates and underestimate the total remediation time.

Patterns of entrapped air dissolution in a two-dimensional pilot-scale synthetic aquifer.

PubMed

McLeod, Heather C; Roy, James W; Smith, James E

2015-01-01

Past studies of entrapped air dissolution have focused on one-dimensional laboratory columns. Here the multidimensional nature of entrapped air dissolution was investigated using an indoor tank (180 × 240 × 600 cm(3) ) simulating an unconfined sand aquifer with horizontal flow. Time domain reflectometry (TDR) probes directly measured entrapped air contents, while dissolved gas conditions were monitored with total dissolved gas pressure (PTDG ) probes. Dissolution occurred as a diffuse wedge-shaped front from the inlet downgradient, with preferential dissolution at depth. This pattern was mainly attributed to increased gas solubility, as shown by PTDG measurements. However, compression of entrapped air at greater depths, captured by TDR and leading to lower quasi-saturated hydraulic conductivities and thus greater velocities, also played a small role. Linear propagation of the dissolution front downgradient was observed at each depth, with both TDR and PTDG , with increasing rates with depth (e.g, 4.1 to 5.7× slower at 15 cm vs. 165 cm depth). PTDG values revealed equilibrium with the entrapped gas initially, being higher at greater depth and fluctuating with the barometric pressure, before declining concurrently with entrapped air contents to the lower PTDG of the source water. The observed dissolution pattern has long-term implications for a wide variety of groundwater management issues, from recharge to contaminant transport and remediation strategies, due to the persistence of entrapped air near the water table (potential timescale of years). This study also demonstrated the utility of PTDG probes for simple in situ measurements to detect entrapped air and monitor its dissolution. © 2014 Her Majesty the Queen in Right of Canada Groundwater © 2014, National Ground Water Association.

Evaluating the reliability of equilibrium dissolution assumption from residual gasoline in contact with water saturated sands.

PubMed

Lekmine, Greg; Sookhak Lari, Kaveh; Johnston, Colin D; Bastow, Trevor P; Rayner, John L; Davis, Greg B

2017-01-01

Understanding dissolution dynamics of hazardous compounds from complex gasoline mixtures is a key to long-term predictions of groundwater risks. The aim of this study was to investigate if the local equilibrium assumption for BTEX and TMBs (trimethylbenzenes) dissolution was valid under variable saturation in two dimensional flow conditions and evaluate the impact of local heterogeneities when equilibrium is verified at the scale of investigation. An initial residual gasoline saturation was established over the upper two-thirds of a water saturated sand pack. A constant horizontal pore velocity was maintained and water samples were recovered across 38 sampling ports over 141days. Inside the residual NAPL zone, BTEX and TMBs dissolution curves were in agreement with the TMVOC model based on the local equilibrium assumption. Results compared to previous numerical studies suggest the presence of small scale dissolution fingering created perpendicular to the horizontal dissolution front, mainly triggered by heterogeneities in the medium structure and the local NAPL residual saturation. In the transition zone, TMVOC was able to represent a range of behaviours exhibited by the data, confirming equilibrium or near-equilibrium dissolution at the scale of investigation. The model locally showed discrepancies with the most soluble compounds, i.e. benzene and toluene, due to local heterogeneities exhibiting that at lower scale flow bypassing and channelling may have occurred. In these conditions mass transfer rates were still high enough to fall under the equilibrium assumption in TMVOC at the scale of investigation. Comparisons with other models involving upscaled mass transfer rates demonstrated that such approximations with TMVOC could lead to overestimate BTEX dissolution rates and underestimate the total remediation time. Copyright © 2016. Published by Elsevier B.V.

Carbonate dissolution rates in high salinity brines: Implications for post-Noachian chemical weathering on Mars

NASA Astrophysics Data System (ADS)

Phillips-Lander, Charity M.; Parnell, S. R.; McGraw, L. E.; Elwood Madden, M. E.

2018-06-01

A diverse suite of carbonate minerals including calcite (CaCO3) and magnesite (MgCO3) have been observed on the martian surface and in meteorites. Terrestrial carbonates usually form via aqueous processes and often record information about the environment in which they formed, including chemical and textural biosignatures. In addition, terrestrial carbonates are often found in association with evaporite deposits on Earth. Similar high salinity environments and processes were likely active on Mars and some areas may contain active high salinity brines today. In this study, we directly compare calcite and magnesite dissolution in ultrapure water, dilute sulfate and chloride solutions, as well as near-saturated sulfate and chloride brines with known activity of water (aH2O) to determine how dissolution rates vary with mineralogy and aH2O, as well as aqueous cation and anion chemistry to better understand how high salinity fluids may have altered carbonate deposits on Mars. We measured both calcite and magnesite initial dissolution rates at 298 K and near neutral pH (6-8) in unbuffered solutions containing ultrapure water (18 MΩ cm-1 UPW; aH2O = 1), dilute (0.1 mol kg-1; aH2O = 1) and near-saturated Na2SO4 (2.5 mol kg-1, aH2O = 0.92), dilute (0.1 mol kg-1, aH2O = 1) and near-saturated NaCl (5.7 mol kg-1, aH2O = 0.75). Calcite dissolution rates were also measured in dilute and near-saturated MgSO4 (0.1 mol kg-1, aH2O = 1 and 2.7 mol kg-1, aH2O = 0.92, respectively) and MgCl2 (0.1 mol kg-1, aH2O = 1 and 3 mol kg-1, aH2O = 0.73, respectively), while magnesite dissolution rates were measured in dilute and near-saturated CaCl2 (0.1 mol kg-1, aH2O = 1 and 9 mol kg-1, aH2O = 0.35). Initial calcite dissolution rates were fastest in near-saturated MgCl2 brine, while magnesite dissolution rates were fastest in dilute (0.1 mol kg-1) NaCl and CaCl2 solutions. Calcite dissolution rates in near-saturated Na2SO4 were similar to those observed in the dilute solutions (-8.00 ± 0.12 log mol m-2 s-1), while dissolution slowed in both NaCl solutions (0.1 mol kg-1; -8.23 ± 0.10 log mol m-2 s-1 and (5.7 mol kg-1; -8.44 ± 0.11 log mol m-2 s-1), as well as near-saturated MgSO4 brine (2.7 mol kg-1; -8.35 ± 0.05 log mol m-2 s-1). The slowest calcite dissolution rates observed in the near-saturated NaCl brine. Magnesite dissolution rates were ∼5 times faster in the dilute salt solutions relative to UPW, but similar to UPW (-8.47 ± 0.06 log mol m-2 s-1) in near-saturated Na2SO4 brines (-8.41 ± 0.18 log mol m-2 s-1). Magnesite dissolution slowed significantly in near-saturated CaCl2 brine (-9.78 ± 0.10 log mol m-2 s-1), likely due to the significantly lower water activity in these experiments. Overall, magnesite dissolution rates are slower than calcite dissolution rates and follow the trend: All dilute salt solutions >2.5 mol kg-1 Na2SO4 ≈ UPW > 5.7 mol kg-1 NaCl >> 9 mol kg-1 CaCl2. Calcite rates follow the trend 3 mol kg-1 MgCl2 > 2.5 mol kg-1 Na2SO4 ≈ UPW ≈ all dilute salt solutions >2.7 mol kg-1 MgSO4 ≈ 5.7 mol kg-1 NaCl. Magnesite dissolution rates in salt solutions generally decrease with decreasing aH2O in both chloride and sulfate brines, which indicates water molecules act as ligands and participate in the rate-limiting magnesite dissolution step. However, there is no general trend associated with water activity observed in the calcite dissolution rates. Calcite dissolution accelerates in near-saturated MgCl2, but slows in near-saturated NaCl brine despite both brines having similar water activities (aH2O = 0.73 and 0.75, respectively). High Mg calcite was observed as a reaction product in the near-saturated MgCl2, indicating Mg2+ from solution likely substituted for Ca2+ in the initial calcite, releasing additional Ca2+ into solution and increasing the observed calcite dissolution rate. Calcite dissolution rates also increase slightly as Na2SO4 concentration increases, while calcite dissolution rates slow slightly with increasing concentration of MgSO4 and NaCl. However, all of the carbonate rates vary by less than 0.5 log units and are within or near the standard deviation observed for each set of replicate experiments. Carbonate mineral lifetimes in high salinity brines indicate magnesite may be preferentially preserved compared to calcite on Mars. Therefore, Mg-carbonates that have experienced post-depositional aqueous alteration are more likely to preserve paleoenvironmental indicators and potential biosignatures. Rapid weathering of carbonates in circum-neutral pH sulfate brines may provide a potential source of cations for abundant sulfate minerals observed on Mars, Ceres, and other planetary bodies.

How good is cola for dissolution of gastric phytobezoars?

PubMed

Lee, Beom-Jae; Park, Jong-Jae; Chun, Hoon-Jai; Kim, Ji-Hoon; Yeon, Jong-Eun; Jeen, Yoon-Tae; Kim, Jae-Seon; Byun, Kwan-Soo; Lee, Sang-Woo; Choi, Jae-Hyun; Kim, Chang-Duck; Ryu, Ho-Sang; Bak, Young-Tae

2009-05-14

To evaluate the efficacy of cola treatment for gastric phytobezoars, including diospyrobezoars. A total of 17 patients (range: 48 to 78 years) with symptomatic gastric phytobezoars treated with cola and adjuvant endoscopic therapy were reviewed. Three liters of cola lavage (10 cases) or drink (7 cases) were initially used, and then endoscopic fragmentation was done for the remnant bezoars by using a lithotripsy basket or a polypectomy snare. The overall success of dissolving a gastric phytobezoars with using three liters of cola and the clinical and endoscopic findings were compared retrospectively between four cases of complete dissolution by using only cola and 13 cases of partial dissolution with cola. After 3 L of cola lavage or drinking, a complete dissolution of bezoars was achieved in four patients (23.5%), while 13 cases (76.5%) were only partially dissolved. Phytobezoars (4 of 6 cases) were observed more frequently than diospyrobezoars (0 of 11) in the group that underwent complete dissolution (P = 0.006). Gender, symptom duration, size of bezoar and method of cola administration were not significantly different between the two groups. Twelve of 13 patients with residual bezoars were completely treated with a combination of cola and endoscopic fragmentation. The rate of complete dissolution with three liters of cola was 23.5%, but no case of diospyrobezoar was completely dissolved using this method. However, pretreatment with cola may be helpful and facilitate endoscopic fragmentation of gastric phytobezoars.

Improving the dissolution rate of poorly water soluble drug by solid dispersion and solid solution: pros and cons.

PubMed

Chokshi, Rina J; Zia, Hossein; Sandhu, Harpreet K; Shah, Navnit H; Malick, Waseem A

2007-01-01

The solid dispersions with poloxamer 188 (P188) and solid solutions with polyvinylpyrrolidone K30 (PVPK30) were evaluated and compared in an effort to improve aqueous solubility and bioavailability of a model hydrophobic drug. All preparations were characterized by differential scanning calorimetry, powder X-ray diffraction, intrinsic dissolution rates, and contact angle measurements. Accelerated stability studies also were conducted to determine the effects of aging on the stability of various formulations. The selected solid dispersion and solid solution formulations were further evaluated in beagle dogs for in vivo testing. Solid dispersions were characterized to show that the drug retains its crystallinity and forms a two-phase system. Solid solutions were characterized to be an amorphous monophasic system with transition of crystalline drug to amorphous state. The evaluation of the intrinsic dissolution rates of various preparations indicated that the solid solutions have higher initial dissolution rates compared with solid dispersions. However, after storage at accelerated conditions, the dissolution rates of solid solutions were lower due to partial reversion to crystalline form. The drug in solid dispersion showed better bioavailability in comparison to solid solution. Therefore, considering physical stability and in vivo study results, the solid dispersion was the most suitable choice to improve dissolution rates and hence the bioavailability of the poorly water soluble drug.

MICROCHARACTERIZATION OF ARSENIC- AND SELENIUM-BEARING PYRITE IN UPPER FREEPORT COAL, INDIANA COUNTY, PENNSYLVANIA.

USGS Publications Warehouse

Minkin, J.A.; Finkelman, R.B.; Thompson, C.L.; Chao, E.C.T.; Ruppert, L.F.; Blank, H.; Cecil, C.B.

1984-01-01

Optical and scanning electron microscope as well as electron and proton microprobe techniques have been used in a detailed investigation of the modes of occurrence of arsenic and selenium in pyrite in Upper Freeport coal from the Homer City area, Indiana County, Pennsylvania. Polished blocks were prepared from columnar samples of the coal bed to represent particular zones continuously from top to bottom. Initial selection of zones to be studied was based on chemical analysis of bench-channel samples. Microprobe data indicate that the highest concentrations of arsenic (as great as 1. 5 wt. %) are apparently in solid solution in pyrite within a limited stratigraphic interval of the coal bed. Smaller amounts of arsenic and selenium (concentrations up to approximately 0. 1 and 0. 2 wt. % respectively) were detected at isolated points within pyrite grains in various strata of the coal bed.

Coal-derived humus: plant growth effects

DOE Office of Scientific and Technical Information (OSTI.GOV)

Freeman, P.G.; Fowkes, W.W.

The growth-promoting properties of coal-derived humus were tested by a variety of bioassay methods. Humate materials used included leonardite, a form of naturally oxidized lignite, and humic acids extracted from leonardite. It was found that the greatest effects were evident when water-soluble humic acid was applied to excised root tips. No significant short-term effect was noted when water-soluble humic acid was applied to stem or coleoptile sections. Root initiation was promoted in bean stems when high concentrations of coal-derived humate were applied. Gross weight of tomato plants was increased by up to 40 percent when coal-derived humates were added inmore » concentrations of 10/sup 1/ to 10/sup 4/ ppM to the nutrient in a hydroponic growth test of 6 weeks' duration. It is concluded that coal-derived humate promotes the uptake of minerals, specifically iron, by serving as a metal chelate.« less

Gasification in pulverized coal flames. First quarterly progress report, July--September 1975

DOE Office of Scientific and Technical Information (OSTI.GOV)

Laurendeau, N. M.

1975-10-01

This project is concerned with the production of power and synthesis gases from pulverized coal via suspension gasification. Specifically, the concentric jet and vortex gasifiers, with separation of oxidation and reduction zones, will be investigated. Gasifier performance will be correlated with internally measured temperature and concentration profiles. A suction pyrometer will be used to simultaneously measure temperature and gas concentrations. Rapid species analysis will be provided by a UTI Q-30C mass spectrometer system. To date, a coal-handling facility has been developed, test cell design has been initiated, and preliminary literature searches have been made. A coal crusher, pulverizer, feeder, andmore » sieve shaker are on order. Preliminary consultations are underway concerning the mass spectrometer system. (auth)« less

Method for control of subsurface coal gasification

DOEpatents

Komar, Charles A.

1976-12-14

The burn front in an in situ underground coal gasification operation is controlled by utilizing at least two parallel groups of vertical bore holes disposed in the coalbed at spaced-apart locations in planes orthogonal to the plane of maximum permeability in the coalbed. The combustion of the coal is initiated in the coalbed adjacent to one group of the bore holes to establish a combustion zone extending across the group while the pressure of the combustion supporting gas mixture and/or the combustion products is regulated at each well head by valving to control the burn rate and maintain a uniform propagation of the burn front between the spaced-apart hole groups to gasify virtually all the coal lying therebetween.

Optimization of biogenic methane production from coal

DOE PAGES

Fuertez, John; Nguyen, Van; McLennan, John D.; ...

2017-09-29

Given continuously increasing global energy needs, diversified efforts have been made to find and exploit new natural gas resources. These include coalbed methane (CBM), which represents an important global, unconventional source of natural gas. Efforts have been underway for some time to more effectively generate methane in-situ in coal plays by introduction of nutrients and/or microbial consortia. However, much is still to be learned about the limitations and environmental conditions that support microbial growth and are conducive to biogenic methane production from coal. Here we evaluated environmental conditions that led to increased methane production from subbituminous coal by introducing amore » foreign methanogenic consortium that included Methanobacterium sp. Furthermore, we used a central composite design (CCD) to explore a broad range of operational conditions, examine the effects of the important environmental factors, such as temperature, pH and salt concentration, and query a feasible region of operation to maximize methane production from coal. An anticipated detrimental effect of NaCl concentration on methane production was observed for the consortium assessed. The range of feasible operational conditions comprised initial pH values between 4.2 and 6.8, temperatures between 23 °C and 37 °C, and NaCl concentrations between 3.7 mg/cm 3 and 9.0 mg/cm 3. Coal biogasification was optimal for this consortium at an initial pH value of 5.5, at 30 °C, and at a NaCl concentration 3.7 mg/cm 3 (i.e., 145,165 ppm, which is 25.6 sft 3/ton).« less

Optimization of biogenic methane production from coal

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fuertez, John; Nguyen, Van; McLennan, John D.

Given continuously increasing global energy needs, diversified efforts have been made to find and exploit new natural gas resources. These include coalbed methane (CBM), which represents an important global, unconventional source of natural gas. Efforts have been underway for some time to more effectively generate methane in-situ in coal plays by introduction of nutrients and/or microbial consortia. However, much is still to be learned about the limitations and environmental conditions that support microbial growth and are conducive to biogenic methane production from coal. Here we evaluated environmental conditions that led to increased methane production from subbituminous coal by introducing amore » foreign methanogenic consortium that included Methanobacterium sp. Furthermore, we used a central composite design (CCD) to explore a broad range of operational conditions, examine the effects of the important environmental factors, such as temperature, pH and salt concentration, and query a feasible region of operation to maximize methane production from coal. An anticipated detrimental effect of NaCl concentration on methane production was observed for the consortium assessed. The range of feasible operational conditions comprised initial pH values between 4.2 and 6.8, temperatures between 23 °C and 37 °C, and NaCl concentrations between 3.7 mg/cm 3 and 9.0 mg/cm 3. Coal biogasification was optimal for this consortium at an initial pH value of 5.5, at 30 °C, and at a NaCl concentration 3.7 mg/cm 3 (i.e., 145,165 ppm, which is 25.6 sft 3/ton).« less

Model-based estimation of adiabatic flame temperature during coal gasification

NASA Astrophysics Data System (ADS)

Sarigul, Ihsan Mert

Coal gasification temperature distribution in the gasifier is one of the important issues. High temperature may increase the risk of corrosion of the gasifier wall or it may cause an increase in the amount of volatile compounds. At the same time, gasification temperature is a dominant factor for high conversion of products and completing the reactions during coal gasification in a short time. In the light of this information it can be said that temperature is one of key parameters of coal gasification to enhance the production of high heating value syngas and maximize refractory longevity. This study aims to predict the adiabatic flame temperatures of Australian bituminous coal and Indonesian roto coal in an entrained flow gasifier using different operating conditions with the ChemCAD simulation and design program. To achieve these objectives, two types of gasification parameters were carried out using simulation of a vertical entrained flow reactor: oxygen-to-coal feed ratio by kg/kg and pressure and steam-to-coal feed ratio by kg/kg and pressure. In the first part of study the adiabatic flame temperatures, coal gasification products and other coal characteristics of two types of coals were determined using ChemCAD software. During all simulations, coal feed rate, coal particle size, initial temperature of coal, water and oxygen were kept constant. The relationships between flame temperature, coal gasification products and operating parameters were fundamentally investigated. The second part of this study addresses the modeling of the flame temperature relation to methane production and other input parameters used previous chapter. The scope of this work was to establish a reasonable model in order to estimate flame temperature without any theoretical calculation. Finally, sensitivity analysis was performed after getting some basic correlations between temperature and input variables. According to the results, oxygen-to-coal feed ratio has the most influential effect on adiabatic flame temperature.

Dissolution of aragonite-strontianite solid solutions in nonstoichiometric Sr (HCO3)2-Ca (HCO3)2-CO2-H2O solutions

USGS Publications Warehouse

Plummer, Niel; Busenberg, E.; Glynn, P.D.; Blum, A.E.

1992-01-01

Synthetic strontianite-aragonite solid-solution minerals were dissolved in CO2-saturated non-stoichiometric solutions of Sr(HCO3)2 and Ca(HCO3)2 at 25??C. The results show that none of the dissolution reactions reach thermodynamic equilibrium. Congruent dissolution in Ca(HCO3)2 solutions either attains or closely approaches stoichiometric saturation with respect to the dissolving solid. In Sr(HCO3)2 solutions the reactions usually become incongruent, precipitating a Sr-rich phase before reaching stoichiometric saturation. Dissolution of mechanical mixtures of solids approaches stoichiometric saturation with respect to the least stable solid in the mixture. Surface uptake from subsaturated bulk solutions was observed in the initial minutes of dissolution. This surficial phase is 0-10 atomic layers thick in Sr(HCO3)2 solutions and 0-4 layers thick in Ca(HCO3)2 solutions, and subsequently dissolves and/or recrystallizes, usually within 6 min of reaction. The initial transient surface precipitation (recrystallization) process is followed by congruent dissolution of the original solid which proceeds to stoichiometric saturation, or until the precipitation of a more stable Sr-rich solid. The compositions of secondary precipitates do not correspond to thermodynamic equilibrium or stoichiometric saturation states. X-ray photoelectron spectroscopy (XPS) measurements indicate the formation of solid solutions on surfaces of aragonite and strontianite single crystals immersed in Sr(HCO3)2 and Ca(HCO3)2 solutions, respectively. In Sr(HCO3)2 solutions, the XPS signal from the outer ~ 60 A?? on aragonite indicates a composition of 16 mol% SrCO3 after only 2 min of contact, and 14-18 mol% SrCO3 after 3 weeks of contact. The strontianite surface averages approximately 22 mol% CaCO3 after 2 min of contact with Ca(HCO3)2 solution, and is 34-39 mol% CaCO3 after 3 weeks of contact. XPS analysis suggests the surface composition is zoned with somewhat greater enrichment in the outer ~25 A?? (as much as 26 mol% SrCO3 on aragonite and 44 mol% CaCO3 on strontianite). The results indicate rapid formation of a solid-solution surface phase from subsaturated aqueous solutions. The surface phase continually adjusts in composition in response to changes in composition of the bulk fluid as net dissolution proceeds. Dissolution rates of the endmembers are greatly reduced in nonstoichiometric solutions relative to dissolution rates observed in stoichiometric solutions. All solids dissolve more slowly in solutions spiked with the least soluble component ((Sr(HCO3)2)) than in solutions spiked with the more soluble component (Ca(HCO3)2), an effect that becomes increasingly significant as stoichiometric saturation is approached. It is proposed that the formation of a non-stoichiometric surface reactive zone significantly decreases dissolution rates. ?? 1992.

Characterization of airborne float coal dust emitted during continuous mining, longwall mining and belt transport.

PubMed

Shahan, M R; Seaman, C E; Beck, T W; Colinet, J F; Mischler, S E

2017-09-01

Float coal dust is produced by various mining methods, carried by ventilating air and deposited on the floor, roof and ribs of mine airways. If deposited, float dust is re-entrained during a methane explosion. Without sufficient inert rock dust quantities, this float coal dust can propagate an explosion throughout mining entries. Consequently, controlling float coal dust is of critical interest to mining operations. Rock dusting, which is the adding of inert material to airway surfaces, is the main control technique currently used by the coal mining industry to reduce the float coal dust explosion hazard. To assist the industry in reducing this hazard, the Pittsburgh Mining Research Division of the U.S. National Institute for Occupational Safety and Health initiated a project to investigate methods and technologies to reduce float coal dust in underground coal mines through prevention, capture and suppression prior to deposition. Field characterization studies were performed to determine quantitatively the sources, types and amounts of dust produced during various coal mining processes. The operations chosen for study were a continuous miner section, a longwall section and a coal-handling facility. For each of these operations, the primary dust sources were confirmed to be the continuous mining machine, longwall shearer and conveyor belt transfer points, respectively. Respirable and total airborne float dust samples were collected and analyzed for each operation, and the ratio of total airborne float coal dust to respirable dust was calculated. During the continuous mining process, the ratio of total airborne float coal dust to respirable dust ranged from 10.3 to 13.8. The ratios measured on the longwall face were between 18.5 and 21.5. The total airborne float coal dust to respirable dust ratio observed during belt transport ranged between 7.5 and 21.8.

Studies of coupled chemical and catalytic coal conversion methods

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stock, L.M.

1988-01-01

Liquefaction of coal by depolymerization in an organic solvent has been studied for several years. The liquefied coal extract which results from such a process is far more suitable for conversion into liquid fuel by hydrogenolysis than is the untreated coal. Investigations on the chemical structure and the reactive sites of coal can help to select useful reactions for the production of liquids from coal. Sternberg et al. demonstrated that the reductive alkylation method transforms bituminous coal into an enormously soluble substance, irrespective of the mild reaction conditions. The effectiveness of newly introduced alkyl groups for the disruption of intermolecularmore » hydrogen bonds and pi-pi interactions between the aromatic sheets in coal macromolecules has been recognized. It has been reported by Ignasiak et al. that a C-alkylabon reaction using sodium or potassium amide in liquid ammonia can be used to introduce alkyl groups at acidic carbon sites. A method has been developed recently in this laboratory for the solubilization of high rank coals. In the previous reports it was shown that n-butyl lithium and potassium t-butoxide in refluxing heptane produced coal anions which could be alkylated with different alkyl halides. Such alkylated coals were soluble up to 92% in solvents like pyridine. Though the solubilization of coal depended very much on the length of the alkyl group, it also depended very much on the nature of the base used. Strong bases like n-butyl lithium (pKa=42) can cause proton abstraction from aromatic structures, if the more acidic benzylic protons are absent. The utility of this procedure, initially developed and used by Miyake and Stock, has now been tested with the high oxygen containing, low rank Illinois No. 6 and Wyodak coals.« less

Studies of coupled chemical and catalytic coal conversion methods. Fifth quarterly report, October--December 1988

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stock, L.M.

1988-12-31

Liquefaction of coal by depolymerization in an organic solvent has been studied for several years. The liquefied coal extract which results from such a process is far more suitable for conversion into liquid fuel by hydrogenolysis than is the untreated coal. Investigations on the chemical structure and the reactive sites of coal can help to select useful reactions for the production of liquids from coal. Sternberg et al. demonstrated that the reductive alkylation method transforms bituminous coal into an enormously soluble substance, irrespective of the mild reaction conditions. The effectiveness of newly introduced alkyl groups for the disruption of intermolecularmore » hydrogen bonds and pi-pi interactions between the aromatic sheets in coal macromolecules has been recognized. It has been reported by Ignasiak et al. that a C-alkylabon reaction using sodium or potassium amide in liquid ammonia can be used to introduce alkyl groups at acidic carbon sites. A method has been developed recently in this laboratory for the solubilization of high rank coals. In the previous reports it was shown that n-butyl lithium and potassium t-butoxide in refluxing heptane produced coal anions which could be alkylated with different alkyl halides. Such alkylated coals were soluble up to 92% in solvents like pyridine. Though the solubilization of coal depended very much on the length of the alkyl group, it also depended very much on the nature of the base used. Strong bases like n-butyl lithium (pKa=42) can cause proton abstraction from aromatic structures, if the more acidic benzylic protons are absent. The utility of this procedure, initially developed and used by Miyake and Stock, has now been tested with the high oxygen containing, low rank Illinois No. 6 and Wyodak coals.« less

Characterization, dissolution and solubility of the hydroxypyromorphite-hydroxyapatite solid solution [(PbxCa1-x)5(PO4)3OH] at 25 °C and pH 2-9.

PubMed

Zhu, Yinian; Huang, Bin; Zhu, Zongqiang; Liu, Huili; Huang, Yanhua; Zhao, Xin; Liang, Meina

2016-01-01

The interaction between Ca-HAP and Pb(2+) solution can result in the formation of a hydroxyapatite-hydroxypyromorphite solid solution [(PbxCa1-x)5(PO4)3(OH)], which can greatly affect the transport and distribution of toxic Pb in water, rock and soil. Therefore, it's necessary to know the physicochemical properties of (PbxCa1-x)5(PO4)3(OH), predominantly its thermodynamic solubility and stability in aqueous solution. Nevertheless, no experiment on the dissolution and related thermodynamic data has been reported. Dissolution of the hydroxypyromorphite-hydroxyapatite solid solution [(PbxCa1-x)5(PO4)3(OH)] in aqueous solution at 25 °C was experimentally studied. The aqueous concentrations were greatly affected by the Pb/(Pb + Ca) molar ratios (XPb) of the solids. For the solids with high XPb [(Pb0.89Ca0.11)5(PO4)3OH], the aqueous Pb(2+) concentrations increased rapidly with time and reached a peak value after 240-720 h dissolution, and then decreased gradually and reached a stable state after 5040 h dissolution. For the solids with low XPb (0.00-0.80), the aqueous Pb(2+) concentrations increased quickly with time and reached a peak value after 1-12 h dissolution, and then decreased gradually and attained a stable state after 720-2160 h dissolution. The dissolution process of the solids with high XPb (0.89-1.00) was different from that of the solids with low XPb (0.00-0.80). The average K sp values were estimated to be 10(-80.77±0.20) (10(-80.57)-10(-80.96)) for hydroxypyromorphite [Pb5(PO4)3OH] and 10(-58.38±0.07) (10(-58.31)-10(-58.46)) for calcium hydroxyapatite [Ca5(PO4)3OH]. The Gibbs free energies of formation (ΔG f (o) ) were determined to be -3796.71 and -6314.63 kJ/mol, respectively. The solubility decreased with the increasing Pb/(Pb + Ca) molar ratios (XPb) of (PbxCa1‒x)5(PO4)3(OH). For the dissolution at 25 °C with an initial pH of 2.00, the experimental data plotted on the Lippmann diagram showed that the solid solution (PbxCa1-x)5(PO4)3(OH) dissolved stoichiometrically at the early stage of dissolution and moved gradually up to the Lippmann solutus curve and the saturation curve for Pb5(PO4)3OH, and then the data points moved along the Lippmann solutus curve from right to left. The Pb-rich (PbxCa1-x)5(PO4)3(OH) was in equilibrium with the Ca-rich aqueous solution. Graphical abstractLippmann diagrams for dissolution of the hydroxypyromorphite-hydroxyapatite solid solution [(PbxCa1-x)5(PO4)3OH] at 25 ˚C and an initial pH of 2.00.

CO2 Adsorption in Low-Rank Coals: Progress Toward Assessing the National Capacity to Store CO2 in the Subsurface

NASA Astrophysics Data System (ADS)

Stanton, R. W.; Burruss, R. C.; Flores, R. M.; Warwick, P. D.

2001-05-01

Subsurface environments for geologic storage of CO2 from combustion of fossil fuel include saline formations, depleted oil and gas reservoirs, and unmineable coalbeds. Of these environments, storage in petroleum reservoirs and coal beds offers a potential economic benefit of enhanced recovery of energy resources. Meaningful assessment of the volume and geographic distribution of storage sites requires quantitative estimates of geologic factors that control storage capacity. The factors that control the storage capacity of unmineable coalbeds are poorly understood. In preparation for a USGS assessment of CO2 storage capacity we have begun new measurements of CO2 and CH4 adsorption isotherms of low-rank coal samples from 4 basins. Initial results for 13 samples of low-rank coal beds from the Powder River Basin (9 subbituminous coals), Greater Green River Basin (1 subbituminous coal), Williston Basin (2 lignites) and the Gulf Coast (1 lignite) indicate that their adsorption capacity is up to 10 times higher than it is for CH4. These values contrast with published measurements of the CO2 adsorption capacity of bituminous coals from the Fruitland Formation, San Juan basin, and Gates Formation, British Columbia, that indicate about twice as much carbon dioxide as methane can be adsorbed on coals. Because CH4 adsorption isotherms are commonly measured on coals, CO2 adsorption capacity can be estimated if thecorrect relationship between the gases is known. However, use a factor to predict CO2 adsorption that is twice that of CH4 adsorption, which is common in the published literature, grossly underestimates the storage capacity of widely distributed, thick low-rank coal beds. Complete petrographic and chemical characterization of these low-rank coal samples is in progress. Significant variations in adsorption measurements among samples are depicted depending on the reporting basis used. Properties were measured on an "as received" (moist) basis but can be converted to a dry basis, ash-free basis (moist), or dry ash-free basis to emphasize the property having the greatest effect on the adsorption isotherm. Initial results show that moisture content has a strong effect on CO2 adsorption. Our current sample base covers a limited range of coal rank and composition. Full characterization of the storage capacity of coalbeds in the US will require additional samples that cover a broader range of coal compositions, ranks, and depositional environments. Even at this preliminary stage, we can use results from the recent USGS assessment of the Powder River Basin (Wyoming and Montana) to examine the impact of these new measurements on estimates of storage capacity. At depths greater than 500 feet, the Wyodak-Anderson coal zone contains 360 billion metric tons of coal. Using the new measurements of CO2 storage capacity, this coal zone could, theoretically, sequester about 290 trillion cubic feet (TCF) of CO2. This estimate contrasts sharply with an estimated capacity of 70 TCF based on the published values for bituminous coals.

The Risk of Divorce as a Barrier to Marriage among Parents of Young Children

PubMed Central

Waller, Maureen R.; Peters, H. Elizabeth

2008-01-01

Using data from the Fragile Families Study, we examine how unmarried parents’ risk of divorce influences their decision to marry. Regression results show that unmarried parents with a high predicted probability of marital dissolution (based on estimates of marital dissolution for a sample of initially married mothers with similar characteristics) had significantly lower odds of marriage to the father of their child even after controlling for individual and relationship characteristics expected to influence marriage transitions. The dissolution propensity we examine also includes a measure of the local divorce climate. As such, our results provide support for the argument that high rates of divorce in the population have led to a fear of divorce among unmarried parents which reduces their probability of marriage. PMID:19227697

The risk of divorce as a barrier to marriage among parents of young children.

PubMed

Waller, Maureen R; Peters, H Elizabeth

2008-12-01

Using data from the Fragile Families Study, we examine how unmarried parents' risk of divorce influences their decision to marry. Regression results show that unmarried parents with a high predicted probability of marital dissolution (based on estimates of marital dissolution for a sample of initially married mothers with similar characteristics) had significantly lower odds of marriage to the father of their child even after controlling for individual and relationship characteristics expected to influence marriage transitions. The dissolution propensity we examine also includes a measure of the local divorce climate. As such, our results provide support for the argument that high rates of divorce in the population have led to a fear of divorce among unmarried parents which reduces their probability of marriage.

43 CFR 4.1128 - Effect of initial order or decision.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 43 Public Lands: Interior 1 2010-10-01 2010-10-01 false Effect of initial order or decision. 4... AND APPEALS PROCEDURES Special Rules Applicable to Surface Coal Mining Hearings and Appeals Evidentiary Hearings § 4.1128 Effect of initial order or decision. An initial order or decision shall become...

A life-cycle description of underground coal mining

NASA Technical Reports Server (NTRS)

Lavin, M. L.; Borden, C. S.; Duda, J. R.

1978-01-01

An initial effort to relate the major technological and economic variables which impact conventional underground coal mining systems, in order to help identify promising areas for advanced mining technology is described. The point of departure is a series of investment analyses published by the United States Bureau of Mines, which provide both the analytical framework and guidance on a choice of variables.

Opportunity for America: Mexico`s coal future

DOE Office of Scientific and Technical Information (OSTI.GOV)

Loose, V.W.

1993-09-01

This study examines the history, current status and future prospects for increased coal use in Mexico. Environmental implications of the power-generation capacity expansion plans are examined in general terms. Mexican environmental law and regulations are briefly reviewed along with the new sense of urgency in the cleanup of existing environmental problems and avoidance of new problems as clearly mandated in recent Mexican government policy initiatives. It is expected that new capital facilities will need to incorporate the latest in process and technology to comply with existing environmental regulation. Technology developments which address these issues are identified. What opportunities have newmore » initiatives caused by the recent diversification of Mexico`s energy economy offered US firms? This report looks at the potential future use of coal in the Mexican energy economy, examining this issue with an eye toward identifying markets that might be available to US coal producers and the best way to approach them. Market opportunities are identified by examining new developments in the Mexican economy generally and the energy economy particularly. These developments are examined in light of the current situation and the history which brought Mexico to its present status.« less

Propagation characteristics of pulverized coal and gas two-phase flow during an outburst.

PubMed

Zhou, Aitao; Wang, Kai; Fan, Lingpeng; Tao, Bo

2017-01-01

Coal and gas outbursts are dynamic failures that can involve the ejection of thousands tons of pulverized coal, as well as considerable volumes of gas, into a limited working space within a short period. The two-phase flow of gas and pulverized coal that occurs during an outburst can lead to fatalities and destroy underground equipment. This article examines the interaction mechanism between pulverized coal and gas flow. Based on the role of gas expansion energy in the development stage of outbursts, a numerical simulation method is proposed for investigating the propagation characteristics of the two-phase flow. This simulation method was verified by a shock tube experiment involving pulverized coal and gas flow. The experimental and simulated results both demonstrate that the instantaneous ejection of pulverized coal and gas flow can form outburst shock waves. These are attenuated along the propagation direction, and the volume fraction of pulverized coal in the two-phase flow has significant influence on attenuation of the outburst shock wave. As a whole, pulverized coal flow has a negative impact on gas flow, which makes a great loss of large amounts of initial energy, blocking the propagation of gas flow. According to comparison of numerical results for different roadway types, the attenuation effect of T-type roadways is best. In the propagation of shock wave, reflection and diffraction of shock wave interact through the complex roadway types.

Propagation characteristics of pulverized coal and gas two-phase flow during an outburst

PubMed Central

Zhou, Aitao; Wang, Kai; Fan, Lingpeng; Tao, Bo

2017-01-01

Coal and gas outbursts are dynamic failures that can involve the ejection of thousands tons of pulverized coal, as well as considerable volumes of gas, into a limited working space within a short period. The two-phase flow of gas and pulverized coal that occurs during an outburst can lead to fatalities and destroy underground equipment. This article examines the interaction mechanism between pulverized coal and gas flow. Based on the role of gas expansion energy in the development stage of outbursts, a numerical simulation method is proposed for investigating the propagation characteristics of the two-phase flow. This simulation method was verified by a shock tube experiment involving pulverized coal and gas flow. The experimental and simulated results both demonstrate that the instantaneous ejection of pulverized coal and gas flow can form outburst shock waves. These are attenuated along the propagation direction, and the volume fraction of pulverized coal in the two-phase flow has significant influence on attenuation of the outburst shock wave. As a whole, pulverized coal flow has a negative impact on gas flow, which makes a great loss of large amounts of initial energy, blocking the propagation of gas flow. According to comparison of numerical results for different roadway types, the attenuation effect of T-type roadways is best. In the propagation of shock wave, reflection and diffraction of shock wave interact through the complex roadway types. PMID:28727738

Simulation Experiment and Acoustic Emission Study on Coal and Gas Outburst

NASA Astrophysics Data System (ADS)

Li, Hui; Feng, Zengchao; Zhao, Dong; Duan, Dong

2017-08-01

A coal and gas outburst is an extreme hazard in underground mining. The present paper conducts a laboratory simulation of a coal and gas outburst combined with acoustic emission analysis. The experiment uses a three-dimensional stress loading system and a PCI-2 acoustic emission monitoring system. Furthermore, the development of a coal and gas outburst is numerically studied. The results demonstrate that the deformation and failure of a coal sample containing methane under three-dimensional stress involves four stages: initial compression, elastic deformation, plastic deformation and failure. The development of internal microscale fractures within a coal sample containing methane is reflected by the distribution of acoustic emission events. We observed that the deformation and failure zone for a coal sample under three-dimensional stress has an ellipsoid shape. Primary acoustic emission events are generated at the weak structural surface that compresses with ease due to the external ellipsoid-shaped stress. The number of events gradually increases until an outburst occurs. A mathematical model of the internal gas pressure and bulk stress is established through an analysis of the internal gas pressure and bulk stress of a coal sample, and it is useful for reproducing experimental results. The occurrence of a coal and gas outburst depends not only on the in situ stress, gas pressure and physical and mechanical characteristics of the coal mass but also on the free weak surface of the outburst outlet of the coal mass. It is more difficult for an outburst to occur from a stronger free surface.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bandosz, T.J.; Petit, C.

Ammonia adsorption was studied under dynamic conditions, at room temperature, on activated carbons of different origins (coal-based, wood-based and coconut-shell-based carbons) before and after their impregnation with various inorganic compounds including metal chlorides, metal oxides and polycations. The role of humidity was evaluated by running tests in both dry and moist conditions. Adsorbents were analyzed before and after exposure to ammonia by thermal analyses, sorption of nitrogen, potentiometric titration, X-ray diffraction and FTIR spectroscopy. Results of breakthrough tests show significant differences in terms of adsorption capacity depending on the parent carbon, the impregnates and the experimental conditions. It is foundmore » that surface chemistry governs ammonia adsorption on the impregnated carbons. More precisely, it was demonstrated that a proper combination of the surface pH, the strength, type and amount of functional groups present on the adsorbents' surface is a key point in ammonia uptake. Water can have either positive or negative effects on the performance of adsorbents. It can enhance NH{sub 3} adsorption capacity since it favors ammonia dissolution and thus enables reaction between ammonium ions and carboxylic groups from the carbons' surface. On the other hand, water can also reduce the performance from the strength of adsorption standpoint. It promotes dissolution of ammonia and that ammonia is first removed from the system when the adsorbent bed is purged with air. Ammonia, besides adsorption by van der Waals forces and dissolution in water, is also retained on the surface via reactive mechanisms such as acid-base reactions (Bronsted and Lewis) or complexation. Depending on the materials used and the experimental conditions, 6-47% ammonia adsorbed is strongly retained on the surface even when the bed is purged with air.« less

Plans moving to tap Rocky Mountain and Eastern US coal for innovative projects

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1980-02-18

Energy Transition Corp. is conducting a study for W.R. Grace and Co. to determine the feasibility of using coal-derived methanol and liquefied carbon dioxide to transport coal in a proposed $500 million coal slurry pipeline from northwestern Colorado to an as-yet unchosen destination. If, as expected, the study shows that the three products can be separated upon delivery, and if suitable synthetic fuels legislation is passed, Grace would decide whether to proceed with the project, which would use technology developed by Koppers Co., Inc., to produce 5000 tons/day of fuel-grade methanol. Permitting and construction would probably take at least fivemore » years. With funding by the US Department of Energy for the initial stages, the Ashland Synthetic Fuels Inc./Airco Energy Co., Inc., Breckenridge Project will plan an H-Coal process plant that will convert 18,000 tons/day of coal to about 50,000 bbl/day of liquid hydrocarbons. The site will be Addison in Breckenridge County, Ky., and the project will probably use high-sulfur Illinois basin coal. The design and construction of the $1.5 billion commercial plant would require about 6.5 yr.« less

Changes in optical properties, chemistry, and micropore and mesopore characteristics of bituminous coal at the contact with dikes in the Illinois Basin

USGS Publications Warehouse

Mastalerz, Maria; Drobniak, A.; Schimmelmann, A.

2009-01-01

Changes in high-volatile bituminous coal (Pennsylvanian) near contacts with two volcanic intrusions in Illinois were investigated with respect to optical properties, coal chemistry, and coal pore structure. Vitrinite reflectance (Ro) increases from 0.62% to 5.03% within a distance of 5.5??m from the larger dike, and from 0.63% to 3.71% within 3.3??m from the small dike. Elemental chemistry of the coal shows distinct reductions in hydrogen and nitrogen content close to the intrusions. No trend was observed for total sulfur content, but decreases in sulfate content towards the dikes indicate thermochemical sulfate reduction (TSR). Contact-metamorphism has a dramatic effect on coal porosity, and microporosity in particular. Around the large dike, the micropore volume, after a slight initial increase, progressively decreases from 0.0417??cm3/g in coal situated 4.7??m from the intrusive contact to 0.0126??cm3/g at the contact. Strongly decreasing mesopore and micropore volumes in the altered zone, together with frequent cleat and fracture filling by calcite, indicate deteriorating conditions for both coalbed gas sorption and gas transmissibility. ?? 2008 Elsevier B.V. All rights reserved.

Application of Paste Backfill in Underground Coal Fires

NASA Astrophysics Data System (ADS)

Masniyom, M.; Drebenstedt, C.

2009-04-01

Coal fires are known from different coalfields worldwide. China, India, USA, Australia, Indonesia and South Africa are the main countries affected by coal fires. The fires is thermally intensive and cause numerous sinkholes, large-scale subsidence, air pollution, global warming, loss of mining productivity and increasing safety risk. The Wuda Inner Mongolia coalfield has been selected as a possible test area for paste backfill. The traditional methods, executed by fire fighting teams, by covering the coalfire areas with soil, blasting burning coal outcrops and injecting water in the subsurface fire pockets are continuously improved and extended. Initiatives to introduce modern techniques, such as backfill placement at fracture and borehole, to cool down the burning coal and cut off the air supply. This study is to investigate backfill materials and techniques suited for underground coal fires. Laboratory tests were carried out on physical, chemical and mechanical properties of different backfill materials and mixtures thereof. Special attention was paid to materials generated as by-products and other cheaply available materials e.g. fly ash from power plants. There is a good chance that one of the different material mixtures investigated can be used as a technically and economically viable backfill for underground coal fires.

The experimental research on response characteristics of coal samples under the uniaxial loading process

NASA Astrophysics Data System (ADS)

Jia, Bing; Wei, Jian-Ping; Wen, Zhi-Hui; Wang, Yun-Gang; Jia, Lin-Xing

2017-11-01

In order to study the response characteristics of infrasound in coal samples under the uniaxial loading process, coal samples were collected from GengCun mine. Coal rock stress loading device, acoustic emission tested system and infrasound tested system were used to test the infrasonic signal and acoustic emission signal under uniaxial loading process. The tested results were analyzed by the methods of wavelet filter, threshold denoise, time-frequency analysis and so on. The results showed that in the loading process, the change of the infrasonic wave displayed the characteristics of stage, and it could be divided into three stages: initial stage with a certain amount infrasound events, middle stage with few infrasound events, and late stage gradual decrease. It had a good consistency with changing characteristics of acoustic emission. At the same time, the frequency of infrasound was very low. It can propagate over a very long distance with little attenuation, and the characteristics of the infrasound before the destruction of the coal samples were obvious. A method of using the infrasound characteristics to predict the destruction of coal samples was proposed. This is of great significance to guide the prediction of geological hazards in coal mines.

Review of China's Low-Carbon City Initiative and Developments in the Coal Industry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fridley, David; Khanna, Nina Zheng; Hong, Lixuan

As China continues its double-digit economic growth, coal remains the principal fuel for the country’s primary energy consumption and electricity generation. China’s dependence on coal in coming years makes its carbon emission intensity reduction targets more difficult to achieve, particularly given rising electricity demand from a growing number of Chinese cities. This paradox has led the government to pursue cleaner and more efficient development of the coal industry on the supply side and “low carbon” development of cities on the demand side. To understand and assess how China may be able to meet its energy and carbon intensity reduction targets,more » this report looks at the recent development of low carbon cities as well as new developments and trends in the coal industry. Specifically, we review low-carbon city and related eco-city development in China before delving into a comparison of eight pilot lowcarbon city plans to highlight their strengths and weaknesses in helping achieve national energy and carbon targets. We then provide insights into the future outlook for China’s coal industry by evaluating new and emerging trends in coal production, consumption, transport, trade and economic performance.« less

On the factors affecting porosity dissolution in selective laser sintering process

NASA Astrophysics Data System (ADS)

Ly, H.-B.; Monteiro, E.; Dal, M.; Regnier, G.

2018-05-01

Selective Laser Sintering process is one of the additive manufacturing techniques in which parts are manufactured layer by layer. During such process, gas bubbles are formed in the melted polymer due to faster polymer grains coalescence at surface than deeper in the powder bed. Although gas diffusion is possible through the polymer melt, it's usual that some porosities remain in the final part if their initial sizes are too big and solidification time too short. In this contribution, a bubble dissolution model involving fluid dynamics and mass transport has been developed to study factors affecting porosity resorption kinetic. In this model, gas diffusion follows Fick's laws and the melted polymer is supposed Newtonian. At the polymer/gas interface, surface tension is considered and Henry's law is used to relate the partial pressure of gas with its concentration in the fluid. This problem is solved numerically by means of the finite element method in 1D. After validation of the numerical tool, the influence on dissolution time of several parameters (e.g. the initial size and form of gas porosities, the viscosity, the diffusion coefficient, the surface tension constant or the ambient pressure) has been examined.

Measuring the Influence of Pearlite Dissolution on the Transient Dynamic Strength of Rapidly Heated Plain Carbon Steels

NASA Astrophysics Data System (ADS)

Mates, Steven; Stoudt, Mark; Gangireddy, Sindhura

2016-07-01

Carbon steels containing ferrite-pearlite microstructures weaken dramatically when pearlite dissolves into austenite on heating. The kinetics of this phase transformation, while fast, can play a role during dynamic, high-temperature manufacturing processes, including high-speed machining, when the time scale of this transformation is on the order of the manufacturing process itself. In such a regime, the mechanical strength of carbon steel can become time dependent. The present work uses a rapidly heated, high-strain-rate mechanical test to study the effect of temperature and time on the amount of pearlite dissolved and on the resulting transient effect on dynamic strength of a low and a high carbon (eutectoid) steel. Measurements indicate that the transient effect occurs for heating times less than about 3 s. The 1075 steel loses about twice the strength compared to the 1018 steel (85 MPa to 45 MPa) owing to its higher initial pearlite volume fraction. Pearlite dissolution is confirmed by metallographic examination of tested samples. Despite the different starting pearlite fractions, the kinetics of dissolution are comparable for the two steels, owing to the similarity in their initial pearlite morphology.

Bioleaching of zinc and manganese from spent Zn-Mn batteries and mechanism exploration.

PubMed

Xin, Baoping; Jiang, Wenfeng; Aslam, Hina; Zhang, Kai; Liu, Changhao; Wang, Renqing; Wang, Yutao

2012-02-01

In this work, bioleaching was used to extract valuable Zn and Mn from spent Zn-Mn batteries. The results showed that 96% of Zn extraction was achieved within 24h regardless of energy source types and bioleaching bacteria species. However, initial pH had a remarkable influence on Zn release, extraction dose sharply decreased from 2200 to 500mg/l when the initial pH value increased from 1.5 to 3.0 or higher. In contrast to Zn, all the tested factors evidently affected Mn extraction; the maximum released dose of 3020mg/l was obtained under the optimum conditions. The acidic dissolution by biogenic H(2)SO(4) by the non-contact mechanism was responsible for Zn extraction, while Mn extraction was owed to both contact/biological and non-contact mechanisms. The combined action of acidic dissolution of soluble Mn(2+) by biogenic H(2)SO(4) and reductive dissolution of insoluble Mn(4+) by Fe(2+) resulted in 60% of Mn extraction, while contact of microbial cells with the spent battery material and incubation for more than 7days was required to achieve the maximum extraction of Mn. Copyright © 2011 Elsevier Ltd. All rights reserved.

Origin, diagnostics, and mitigation of a salt dissolution sinkhole at the US Strategic Petroleum Reserve storage site, Weeks Island, Louisiana

DOE Office of Scientific and Technical Information (OSTI.GOV)

Neal, J.T.; Myers, R.E.

1995-01-27

A sinkhole was first observed in May 1992 over the edge of the two-level former salt mine that was converted for oil storage by the US Strategic Petroleum Reserve (SPR). Diagnostic studies that included geophysical, geochemical, drilling, and hydrological methods suggest a direct connection exists between the surface collapse area and the underground mine as shown by correlative measurements of sediment slump rates and brine influx into the mine. The dissolution of salt below the sinkhole that initiated the leak into the mine was likely caused by several confluent geologic processes, and exacerbated by mining-induced stresses that created fractures whichmore » served as hydrologic flowpaths. Modeling studies of mine stresses show that years may be required before tensional cracking begins to occur, but once begun can continue to develop, and relieve the stress in that specific regime. The crack regime creates the avenue for incursion of groundwater, very slowly initially, but gradually enlarging as undersaturated groundwater dissolves salt on the sides of the crack. Mitigation measures include increasing the mine pressurization, slowing the dissolution by injecting brine into the sinkhole throat, and freeze grouting to restrict hydrologic flowpaths.« less

Probing the mechanisms of drug release from amorphous solid dispersions in medium-soluble and medium-insoluble carriers.

PubMed

Sun, Dajun D; Lee, Ping I

2015-08-10

The objective of the current study is to mechanistically differentiate the dissolution and supersaturation behaviors of amorphous drugs from amorphous solid dispersions (ASDs) based on medium-soluble versus medium-insoluble carriers under nonsink dissolution conditions through a direct head-to-head comparison. ASDs of indomethacin (IND) were prepared in several polymers which exhibit different solubility behaviors in acidic (pH1.2) and basic (pH7.4) dissolution media. The selected polymers range from water-soluble (e.g., PVP and Soluplus) and water-insoluble (e.g., ethylcellulose and Eudragit RL PO) to those only soluble in an acidic or basic dissolution medium (e.g., Eudragit E100, Eudragit L100, and HPMCAS). At 20wt.% drug loading, DSC and powder XRD analysis confirmed that the majority of incorporated IND was present in an amorphous state. Our nonsink dissolution results confirm that whether the carrier matrix is medium soluble determines the release mechanism of amorphous drugs from ASD systems which has a direct impact on the rate of supersaturation generation, thus in turn affecting the evolution of supersaturation in amorphous systems. For example, under nonsink dissolution conditions, the release of amorphous IND from medium-soluble carriers is governed by a dissolution-controlled mechanism leading to an initial surge of supersaturation followed by a sharp decline in drug concentration due to rapid nucleation and crystallization. In contrast, the dissolution of IND ASD from medium-insoluble carriers is more gradual as drug release is regulated by a diffusion-controlled mechanism by which drug supersaturation is built up gradually and sustained over an extended period of time without any apparent decline. Since several tested carrier polymers can be switched from soluble to insoluble by simply changing the pH of the dissolution medium, the results obtained here provide unequivocal evidence of the proposed transition of kinetic solubility profiles from the same ASD system induced by changes in the drug release mechanism in dissolution medium of a different pH. Copyright © 2015 Elsevier B.V. All rights reserved.

Chemical structure influence on NAPL mixture nonideality evolution, rate-limited dissolution, and contaminant mass flux.

PubMed

Padgett, Mark C; Tick, Geoffrey R; Carroll, Kenneth C; Burke, William R

2017-03-01

The influence of chemical structure on NAPL mixture nonideality evolution, rate-limited dissolution, and contaminant mass flux was examined. The variability of measured and UNIFAC modeled NAPL activity coefficients as a function of mole fraction was compared for two NAPL mixtures containing structurally-different contaminants of concern including toluene (TOL) or trichloroethene (TCE) within a hexadecane (HEXDEC) matrix. The results showed that dissolution from the NAPL mixtures transitioned from ideality for mole fractions >0.05 to nonideality as mole fractions decreased. In particular, the TCE generally exhibited more ideal dissolution behavior except at lower mole fractions, and may indicate greater structural/polarity similarity between the two compounds. Raoult's Law and UNIFAC generally under-predicted the batch experiment results for TOL:HEXDEC mixtures especially for mole fractions ≤0.05. The dissolution rate coefficients were similar for both TOL and TCE over all mole fractions tested. Mass flux reduction (MFR) analysis showed that more efficient removal behavior occurred for TOL and TCE with larger mole fractions compared to the lower initial mole fraction mixtures (i.e. <0.2). However, compared to TOL, TCE generally exhibited more efficient removal behavior over all mole fractions tested and may have been the result of structural and molecular property differences between the compounds. Activity coefficient variability as a function of mole fraction was quantified through regression analysis and incorporated into dissolution modeling analyses for the dynamic flushing experiments. TOL elution concentrations were modeled (predicted) reasonable well using ideal and equilibrium assumptions, but the TCE elution concentrations could not be predicted using the ideal model. Rather, the dissolution modeling demonstrated that TCE elution was better described by the nonideal model whereby NAPL-phase activity coefficient varied as a function of COC mole fraction. For dynamic column flushing experiments, dissolution rate kinetics can vary significantly with changes in NAPL volume and surface area. However, under conditions whereby NAPL volume and area are not significantly altered during dissolution, mixture nonideality effects may have a greater relative control on dissolution (elution) and MFR behavior compared to kinetic rate limitations. Copyright © 2017 Elsevier B.V. All rights reserved.

Chemical structure influence on NAPL mixture nonideality evolution, rate-limited dissolution, and contaminant mass flux

NASA Astrophysics Data System (ADS)

Padgett, Mark C.; Tick, Geoffrey R.; Carroll, Kenneth C.; Burke, William R.

2017-03-01

The influence of chemical structure on NAPL mixture nonideality evolution, rate-limited dissolution, and contaminant mass flux was examined. The variability of measured and UNIFAC modeled NAPL activity coefficients as a function of mole fraction was compared for two NAPL mixtures containing structurally-different contaminants of concern including toluene (TOL) or trichloroethene (TCE) within a hexadecane (HEXDEC) matrix. The results showed that dissolution from the NAPL mixtures transitioned from ideality for mole fractions > 0.05 to nonideality as mole fractions decreased. In particular, the TCE generally exhibited more ideal dissolution behavior except at lower mole fractions, and may indicate greater structural/polarity similarity between the two compounds. Raoult's Law and UNIFAC generally under-predicted the batch experiment results for TOL:HEXDEC mixtures especially for mole fractions ≤ 0.05. The dissolution rate coefficients were similar for both TOL and TCE over all mole fractions tested. Mass flux reduction (MFR) analysis showed that more efficient removal behavior occurred for TOL and TCE with larger mole fractions compared to the lower initial mole fraction mixtures (i.e. < 0.2). However, compared to TOL, TCE generally exhibited more efficient removal behavior over all mole fractions tested and may have been the result of structural and molecular property differences between the compounds. Activity coefficient variability as a function of mole fraction was quantified through regression analysis and incorporated into dissolution modeling analyses for the dynamic flushing experiments. TOL elution concentrations were modeled (predicted) reasonable well using ideal and equilibrium assumptions, but the TCE elution concentrations could not be predicted using the ideal model. Rather, the dissolution modeling demonstrated that TCE elution was better described by the nonideal model whereby NAPL-phase activity coefficient varied as a function of COC mole fraction. For dynamic column flushing experiments, dissolution rate kinetics can vary significantly with changes in NAPL volume and surface area. However, under conditions whereby NAPL volume and area are not significantly altered during dissolution, mixture nonideality effects may have a greater relative control on dissolution (elution) and MFR behavior compared to kinetic rate limitations.

Assessment of advanced coal gasification processes

NASA Technical Reports Server (NTRS)

Mccarthy, J.; Ferrall, J.; Charng, T.; Houseman, J.

1981-01-01

A technical assessment of the following advanced coal gasification processes is presented: high throughput gasification (HTG) process; single stage high mass flux (HMF) processes; (CS/R) hydrogasification process; and the catalytic coal gasification (CCG) process. Each process is evaluated for its potential to produce synthetic natural gas from a bituminous coal. Key similarities, differences, strengths, weaknesses, and potential improvements to each process are identified. The HTG and the HMF gasifiers share similarities with respect to: short residence time (SRT), high throughput rate, slagging, and syngas as the initial raw product gas. The CS/R hydrogasifier is also SRT, but is nonslagging and produces a raw gas high in methane content. The CCG gasifier is a long residence time, catalytic, fluidbed reactor producing all of the raw product methane in the gasifier.

Geologic coal assessment: The interface with economics

USGS Publications Warehouse

Attanasi, E.D.

2001-01-01

Geologic resource assessments describe the location, general characteristics, and estimated volumes of resources, whether in situ or technically recoverable. Such compilations are only an initial step in economic resource evaluation. This paper identifies, by examples from the Illinois and Appalachian basins, the salient features of a geologic assessment that assure its usefulness to downstream economic analysis. Assessments should be in sufficient detail to allocate resources to production units (mines or wells). Coal assessments should include the spatial distribution of coal bed characteristics and the ability to allocate parts of the resource to specific mining technologies. For coal bed gas assessment, the production well recoveries and well deliverability characteristics must be preserved and the risk structure should be specified so dryholes and noncommercial well costs are recovered by commercially successful wells. ?? 2001 International Association for Mathematical Geology.

Hydrologic data from wells at or in the vicinity of the San Juan coal mine, San Juan County, New Mexico

USGS Publications Warehouse

Stewart, Anne M.; Thomas, Nicole

2015-01-01

In 2010, in cooperation with the Mining and Minerals Division (MMD) of the State of New Mexico Energy, Minerals and Natural Resources Department, the U.S. Geological Survey (USGS) initiated a 4-year assessment of hydrologic conditions at the San Juan coal mine (SJCM), located about 14 miles west-northwest of the city of Farmington, San Juan County, New Mexico. The mine produces coal for power generation at the adjacent San Juan Generating Station (SJGS) and stores coal-combustion byproducts from the SJGS in mined-out surface-mining pits. The purpose of the hydrologic assessment is to identify groundwater flow paths away from SJCM coal-combustion-byproduct storage sites that might allow metals that may be leached from coal-combustion byproducts to eventually reach wells or streams after regional dewatering ceases and groundwater recovers to predevelopment levels. The hydrologic assessment, undertaken between 2010 and 2013, included compilation of existing data. The purpose of this report is to present data that were acquired and compiled by the USGS for the SJCM hydrologic assessment.

Improving the stability of coal slurries. Quarterly progress report, March 15-June 15, 1986. [Sedimentation tests in the presence and absence of gum tragacanth

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fogler, H.S.

1986-01-01

In this report, we will describe the progress of our research in two key areas. The twin objectives of this research are: (a) to examine the effectiveness of hydrocolloids as stabilizers of coal-water slurries and (b) to gain an understanding of the mechanism of stabilization through the use of monodisperse polystyrene lattices as model systems. Sedimentation tests with ultrafine ground coal in presence and absence of gum tragacanth have been carried out. An isotherm of gum tragacanth binding to coal surface has been generated. We have also conducted rheological studies to characterize the stabilized coal-water slurries. Similar experiments with -200more » mesh coal are currently under way. In the case of model system studies, the effect of article size on the gum tragacanth induced stability has been studied. Initial experiments on the effects of increased electrolyte concentration and the addition of nonsolvents like ethanol to the continuous phase have been undertaken. 9 refs., 16 figs., 1 tab.« less

Oxidation and the Effects of High Temperature Exposures on Notched Fatigue Life of an Advanced Powder Metallurgy Disk Superalloy

NASA Technical Reports Server (NTRS)

Sudbrack, Chantal K.; Draper, Susan L.; Gorman, Timothy T.; Telesman, Jack; Gab, Timothy P.; Hull, David R.

2012-01-01

Oxidation and the effects of high temperature exposures on notched fatigue life were considered for a powder metallurgy processed supersolvus heat-treated ME3 disk superalloy. The isothermal static oxidation response at 704 C, 760 C, and 815 C was consistent with other chromia forming nickel-based superalloys: a TiO2-Cr2O3 external oxide formed with a branched Al2O3 internal subscale that extended into a recrystallized - dissolution layer. These surface changes can potentially impact disk durability, making layer growth rates important. Growth of the external scales and dissolution layers followed a cubic rate law, while Al2O3 subscales followed a parabolic rate law. Cr- rich M23C6 carbides at the grain boundaries dissolved to help sustain Cr2O3 growth to depths about 12 times thicker than the scale. The effect of prior exposures was examined through notched low cycle fatigue tests performed to failure in air at 704 C. Prior exposures led to pronounced debits of up to 99 % in fatigue life, where fatigue life decreased inversely with exposure time. Exposures that produced roughly equivalent 1 m thick external scales at the various isotherms showed statistically equivalent fatigue lives, establishing that surface damage drives fatigue debit, not exposure temperature. Fractographic evaluation indicated the failure mode for the pre-exposed specimens involved surface crack initiations that shifted with exposure from predominately single intergranular initiations with transgranular propagation to multi-initiations from the cracked external oxide with intergranular propagation. Weakened grain boundaries at the surface resulting from the M23C6 carbide dissolution are partially responsible for the intergranular cracking. Removing the scale and subscale while leaving a layer where M23C6 carbides were dissolved did not lead to a significant fatigue life improvement, however, also removing the M23C6 carbide dissolution layer led to nearly full recovery of life, with a transgranular initiation typical to that observed in unexposed specimens.

Trait self-esteem moderates the effect of initiator status on emotional and cognitive responses to romantic relationship dissolution.

PubMed

Waller, Katherine L; MacDonald, Tara K

2010-08-01

We hypothesized that the effect of initiator status on post breakup distress would vary as a function of trait self-esteem, such that individuals with low self-esteem would experience more distress after being rejected by their partners, whereas, among individuals with high self-esteem, initiator status would not predict distress. We used a prospective design in which university students (N=66) were assessed for emotional responses following the dissolution of their real-life romantic relationships, as well as a laboratory design in which students (N=190) imagined breaking up with their partners. As predicted, participants with lower trait self-esteem exhibited greater distress after experiencing or imagining a romantic rejection than after ending or imagining themselves ending their relationships. Conversely, distress experienced by those with high trait self-esteem did not differ as a function of who ended the relationship. Implications for understanding self-esteem processes and the effects of romantic rejection are discussed.

An in situ occurrence of coal balls in the Amburgy coal bed, Pikeville Formation (Duckmantian), central Appalachian Basin, USA

USGS Publications Warehouse

Greb, S.F.; Eble, C.F.; Chesnut, D.R.; Phillips, T.L.; Hower, J.C.

1999-01-01

Carbonate concretions containing permineralized peat, commonly called coal balls, were encountered in the Amburgy coal, a generally low-ash (9.4%), but commonly high-sulfur (3.6%), Middle Pennsylvanian coal of the Eastern Kentucky Coal Field. These are the first coal balls from the Amburgy coal, and one of only a few reported occurrences from the central Appalachian Basin. The coal balls occur in the upper part of the coal, between two paleochannel cut-outs at the top of the Pikeville Formation, and immediately beneath a scour with a marine fossil lag at the base of the Kendrick Shale Member, Hyden Formation. The coal is thickest (1.3 m) in a narrow (<300 m), elongate depression between the bounding paleochannels, and thins toward the occurrence of coal balls. Total biovolume as measured from acetate peels of coal balls indicates cordaites or lycopsid (36.1% each) dominance. Vertical sampling through one coal-ball aggregate shows zoning from a lower cordaites-dominant (88.7%) assemblage, to a middle, degraded, sphenopsid-rich assemblage, to an upper lycopsid-dominant (88.6%) assemblage. Beneath the coal balls, palynologic and petrographic analyses indicate the basal and middle portions of the bed are dominated by arborescent lycopsid spores and cordaites pollen, and by vitrinite macerals. The top part of the bed, above the coal balls, contains increased intertinite macerals, increased percentages of small fern spores, and variable ash yield (5-21%). Thickening of the Amburgy coal along a structural low, in combination with basal high-ash yields, vitrinite-dominance, and heterogenous palynoflora, indicate paleotopographic control on initial peat accumulation. Abundant lycopsid spores in the basal and middle part of the coal reflect rheotrophic conditions consistent with accumulation in a paleotopographic depression. Apparent zonation preserved in one of the coal-ball masses may document plant successions in response to flooding. Similar percentages of cordaites and lycopods, respectively, in the zones above and below the degraded incursion interval reflect development of a mixed, successional pattern in response to the flooding. Coal-ball formation may have been facilitated by channeling along the Kendrick ravinement, within a paleotopographic depression, at the split margin of the Amburgy peat, either through direct transmittal of carbonates and marine waters into the peat, or through degassing of the peat beneath the scour.

Structural changes in C–S–H gel during dissolution: Small-angle neutron scattering and Si-NMR characterization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Trapote-Barreira, Ana, E-mail: anatrapotebarreira@gmail.com; Porcar, Lionel; Large Scale Structure Group, Institut Laue Langevin, Grenoble

2015-06-15

Flow-through experiments were conducted to study the calcium–silicate–hydrate (C–S–H) gel dissolution kinetics. During C–S–H gel dissolution the initial aqueous Ca/Si ratio decreases to reach the stoichiometric value of the Ca/Si ratio of a tobermorite-like phase (Ca/Si = 0.83). As the Ca/Si ratio decreases, the solid C–S–H dissolution rate increases from (4.5 × 10{sup −} {sup 14} to 6.7 × 10{sup −} {sup 12}) mol m{sup −} {sup 2} s{sup −} {sup 1}. The changes in the microstructure of the dissolving C–S–H gel were characterized by small-angle neutron scattering (SANS) and {sup 29}Si magic-angle-spinning nuclear magnetic resonance ({sup 29}Si-MAS NMR). Themore » SANS data were fitted using a fractal model. The SANS specific surface area tends to increase with time and the obtained fit parameters reflect the changes in the nanostructure of the dissolving solid C–S–H within the gel. The {sup 29}Si MAS NMR analyses show that with dissolution the solid C–S–H structure tends to a more ordered tobermorite structure, in agreement with the Ca/Si ratio evolution.« less

Numerical ages of Holocene tributary debris fans inferred from dissolution pitting on carbonate boulders in the Grand Canyon of Arizona

USGS Publications Warehouse

Hereford, R.; Thompson, K.S.; Burke, K.J.

1998-01-01

Carbonate boulders transported down steep tributary channels by debris flow came to rest on Holocene debris fans beside the Colorado River in Grand Canyon National Park. Weakly acidic rainfall and the metabolic activity of blue-green algae have produced roughly hemispheric dissolution pits as much as 2-cm deep on the initially smooth surfaces of the boulders. The average depth of dissolution pits increases with relative age of fan surfaces. The deepening rate averages 2.4 mm/1000 yr (standard error = 0.2 mm/1000 yr), as calculated from several radiometrically dated surfaces and an archeological structure. This linear rate, which appears constant over at least the past 3000 yr, is consistent with field relations limiting the maximum age of the fans and with the physical chemistry of limestone dissolution. Dissolution-pit measurements (n = 6973) were made on 617 boulders on 71 fan surfaces at the 26 largest debris fans in Grand Canyon. Among these fan surfaces, the average pit depth ranges from 1.2 to 17.4 mm, and the resulting pit dissolution ages range from 500 to 7300 cal yr B.P. Most (75%) surfaces are younger than 3000 yr, probably because of removal of older debris fans by the Colorado River. Many of the ages are close to 800, 1600, 2300, 3100, or 4300 cal yr B.P. If not the result of differential preservation of fan surfaces, this clustering implies periods of heightened debris-flow activity and increased precipitation.

How good is cola for dissolution of gastric phytobezoars?

PubMed Central

Lee, Beom Jae; Park, Jong-Jae; Chun, Hoon Jai; Kim, Ji Hoon; Yeon, Jong Eun; Jeen, Yoon Tae; Kim, Jae Seon; Byun, Kwan Soo; Lee, Sang Woo; Choi, Jae Hyun; Kim, Chang Duck; Ryu, Ho Sang; Bak, Young-Tae

2009-01-01

AIM: To evaluate the efficacy of cola treatment for gastric phytobezoars, including diospyrobezoars. METHODS: A total of 17 patients (range: 48 to 78 years) with symptomatic gastric phytobezoars treated with cola and adjuvant endoscopic therapy were reviewed. Three liters of cola lavage (10 cases) or drink (7 cases) were initially used, and then endoscopic fragmentation was done for the remnant bezoars by using a lithotripsy basket or a polypectomy snare. The overall success of dissolving a gastric phytobezoars with using three liters of cola and the clinical and endoscopic findings were compared retrospectively between four cases of complete dissolution by using only cola and 13 cases of partial dissolution with cola. RESULTS: After 3 L of cola lavage or drinking, a complete dissolution of bezoars was achieved in four patients (23.5%), while 13 cases (76.5%) were only partially dissolved. Phytobezoars (4 of 6 cases) were observed more frequently than diospyrobezoars (0 of 11) in the group that underwent complete dissolution (P = 0.006). Gender, symptom duration, size of bezoar and method of cola administration were not significantly different between the two groups. Twelve of 13 patients with residual bezoars were completely treated with a combination of cola and endoscopic fragmentation. CONCLUSION: The rate of complete dissolution with three liters of cola was 23.5%, but no case of diospyrobezoar was completely dissolved using this method. However, pretreatment with cola may be helpful and facilitate endoscopic fragmentation of gastric phytobezoars. PMID:19437568

Analysis of gob gas venthole production performances for strata gas control in longwall mining.

PubMed

Karacan, C Özgen

2015-10-01

Longwall mining of coal seams affects a large area of overburden by deforming it and creating stress-relief fractures, as well as bedding plane separations, as the mining face progresses. Stress-relief fractures and bedding plane separations are recognized as major pathways for gas migration from gas-bearing strata into sealed and active areas of the mines. In order for strata gas not to enter and inundate the ventilation system of a mine, gob gas ventholes (GGVs) can be used as a methane control measure. The aim of this paper is to analyze production performances of GGVs drilled over a longwall panel. These boreholes were drilled to control methane emissions from the Pratt group of coals due to stress-relief fracturing and bedding plane separations into a longwall mine operating in the Mary Lee/Blue Creek coal seam of the Upper Pottsville Formation in the Black Warrior Basin, Alabama. During the course of the study, Pratt coal's reservoir properties were integrated with production data of the GGVs. These data were analyzed by using material balance techniques to estimate radius of influence of GGVs, gas-in-place and coal pressures, as well as their variations during mining. The results show that the GGVs drilled to extract gas from the stress-relief zone of the Pratt coal interval is highly effective in removing gas from the Upper Pottsville Formation. The radii of influence of the GGVs were in the order of 330-380 m, exceeding the widths of the panels, due to bedding plane separations and stress relieved by fracturing. Material balance analyses indicated that the initial pressure of the Pratt coals, which was around 648 KPa when longwall mining started, decreased to approximately 150 KPa as the result of strata fracturing and production of released gas. Approximately 70% of the initial gas-in-place within the area of influence of the GGVs was captured during a period of one year.

Geochemistry of Selected Coal Samples from Sumatra, Kalimantan, Sulawesi, and Papua, Indonesia

USGS Publications Warehouse

Belkin, Harvey E.; Tewalt, Susan J.

2007-01-01

Introduction Indonesia is an archipelago of more than 17,000 islands that stretches astride the equator for about 5,200 km in southeast Asia (figure 1) and includes major Cenozoic volcano-plutonic arcs, active volcanoes, and various related onshore and offshore basins. These magmatic arcs have extensive Cu and Au mineralization that has generated much exploration and mining in the last 50 years. Although Au and Ag have been mined in Indonesia for over 1000 years (van Leeuwen, 1994), it was not until the middle of the nineteenth century that the Dutch explored and developed major Sn and minor Au, Ag, Ni, bauxite, and coal resources. The metallogeny of Indonesia includes Au-rich porphyry Cu, porphyry Mo, skarn Cu-Au, sedimentary-rock hosted Au, epithermal Au, laterite Ni, and diamond deposits. For example, the Grasberg deposit in Papua has the world's largest gold reserves and the third-largest copper reserves (Sillitoe, 1994). Coal mining in Indonesia also has had a long history beginning with the initial production in 1849 in the Mahakam coal field near Pengaron, East Kalimantan; in 1891 in the Ombilin area, Sumatra, (van Leeuwen, 1994); and in South Sumatra in 1919 at the Bukit Asam mine (Soehandojo, 1989). Total production from deposits in Sumatra and Kalimantan, from the 19thth century to World War II, amounted to 40 million metric tons (Mt). After World War II, production declined due to various factors including politics and a boom in the world-wide oil economy. Active exploration and increased mining began again in the 1980's mainly through a change in Indonesian government policy of collaboration with foreign companies and the global oil crises (Prijono, 1989). This recent coal revival (van Leeuwen, 1994) has lead Indonesia to become the largest exporter of thermal (steam) coal and the second largest combined thermal and metallurgical (coking) coal exporter in the world market (Fairhead and others, 2006). The exported coal is desirable as it is low sulfur and ash (generally <1 and < 10 wt.%, respectively). Coal mining for both local use and for export has a very strong future in Indonesia although, at present, there are concerns about the strong need for a major revision in mining laws and foreign investment policies (Wahju, 2004; United States Embassy Jakarta, 2004). The World Coal Quality Inventory (WoCQI) program of the U.S. Geological Survey (Tewalt and others, 2005) is a cooperative project with about 50 countries (out of 70 coal-producing countries world-wide). The WoCQI initiative has collected and published extensive coal quality data from the world's largest coal producers and consumers. The important aspects of the WoCQI program are; (1) samples from active mines are collected, (2) the data have a high degree of internal consistency with a broad array of coal quality parameters, and (3) the data are linked to GIS and available through the world-wide-web. The coal quality parameters include proximate and ultimate analysis, sulfur forms, major-, minor-, and trace-element concentrations and various technological tests. This report contains geochemical data from a selected group of Indonesian coal samples from a range of coal types, localities, and ages collected for the WoCQI program.

Dissolution Flowsheet for High Flux Isotope Reactor Fuel

DOE Office of Scientific and Technical Information (OSTI.GOV)

Daniel, W. E.; Rudisill, T. S.; O'Rourke, P. E.

2016-09-27

As part of the Spent Nuclear Fuel (SNF) processing campaign, H-Canyon is planning to begin dissolving High Flux Isotope Reactor (HFIR) fuel in late FY17 or early FY18. Each HFIR fuel core contains inner and outer fuel elements which were fabricated from uranium oxide (U 3O 8) dispersed in a continuous Al phase using traditional powder metallurgy techniques. Fuels fabricated in this manner, like other SNF’s processed in H-Canyon, dissolve by the same general mechanisms with similar gas generation rates and the production of H 2. The HFIR fuel cores will be dissolved and the recovered U will be down-blendedmore » into low-enriched U. HFIR fuel was previously processed in H-Canyon using a unique insert in both the 6.1D and 6.4D dissolvers. Multiple cores will be charged to the same dissolver solution maximizing the concentration of dissolved Al. The objective of this study was to identify flowsheet conditions through literature review and laboratory experimentation to safely and efficiently dissolve the HFIR fuel in H-Canyon. Laboratory-scale experiments were performed to evaluate the dissolution of HFIR fuel using both Al 1100 and Al 6061 T6 alloy coupons. The Al 1100 alloy was considered a representative surrogate which provided an upper bound on the generation of flammable (i.e., H 2) gas during the dissolution process. The dissolution of the Al 6061 T6 alloy proceeded at a slower rate than the Al 1100 alloy, and was used to verify that the target Al concentration in solution could be achieved for the selected Hg concentration. Mass spectrometry and Raman spectroscopy were used to provide continuous monitoring of the concentration of H 2 and other permanent gases in the dissolution offgas, allowing the development of H 2 generation rate profiles. The H 2 generation rates were subsequently used to evaluate if a full HFIR core could be dissolved in an H-Canyon dissolver without exceeding 60% of the calculated lower flammability limit (LFL) for H 2 at a given Hg concentration. Complete dissolution of the Al 1100 and Al 6061 T6 alloys up to a final Al concentration of 2 M was obtained using a 7 M HNO 3 solution containing a 0.002 M Hg catalyst. However, following the dissolutions, solids were observed in the solution. The solids were amorphous, but likely originated from the Si present in the alloys. No crystalline materials, such as Al(NO 3) 3 were observed. During the course of the dissolution experiments, it was determined that delaying the addition of Hg once the HNO 3 solution reached the boiling point can reduce the total offgas and H 2 generation rates. The delay in starting the Hg addition is not necessary for HFIR fuel dissolution, but could be useful in other research reactor dissolution campaigns. The potential to generate flammable concentrations of H 2 in the offgas during a HFIR fuel dissolution was evaluated using the experimental data. The predicted H 2 concentration in the dissolver offgas stream was compared with 60% of the calculated H 2 LFL at 200 °C using several prototypical experiments. The calculations showed that a full HFIR core can be dissolved using nominally 0.002 M Hg to catalyze the dissolution. The margin between the predicted H 2 concentration and the calculated LFL was greater when the solution was allowed to boil for 45 min prior to initiating the Hg addition. When the Hg was increased to 0.004 M, the predicted H 2 concentration exceeded the calculated LFL early in the dissolution. The dissolution experiments also demonstrated that additional Hg (beyond the initial 0.002 M) could be added as the Al concentration increases. The ability to add more Hg during a HFIR fuel dissolution could be beneficial if slow dissolution rates are observed at high Al concentrations. Experimental data were used to demonstrate that the predicted H 2 concentration in a dissolver was below 60% of the calculated LFL at 200 °C when 0.004 M Hg was used to catalyze the dissolution if the Al concentration is conservatively greater than 0.5 M. Data also show that the Hg concentration during a HFIR fuel dissolution can be increased from 0.002 to 0.008 M at an Al concentration of 1.3 M.« less

Effect of modeling factors on the dissolution-diffusion-convection process during CO2 geological storage in deep saline formations

NASA Astrophysics Data System (ADS)

Zhang, Wei

2013-06-01

It is well known that during CO2 geological storage, density-driven convective activity can significantly accelerate the dissolution of injected CO2 into water. This action could limit the escape of supercritical CO2 from the storage formation through vertical pathways such as fractures, faults and abandoned wells, consequently increasing permanence and security of storage. First, we investigated the effect of numerical perturbation caused by time and grid resolution and the convergence criteria on the dissolution-diffusion-convection (DDC) process. Then, using the model with appropriate spatial and temporal resolution, some uncertainty parameters investigated in our previous paper such as initial gas saturation and model boundaries, and other factors such as relative liquid permeability and porosity modification were used to examine their effects on the DDC process. Finally, we compared the effect of 2D and 3D models on the simulation of the DDC process. The above modeling results should contribute to clear understanding and accurate simulation of the DDC process, especially the onset of convective activity, and the CO2 dissolution rate during the convection-dominated stage.

Experimental layering development by indenter technique and application to fault rheology differentiation

NASA Astrophysics Data System (ADS)

Gratier, J. P.; Noiriel, C. N.; Renard, F.

2014-12-01

Natural deformation of rocks is often associated with differentiation processes leading to irreversible transformations of their microstructural thus leading in turn to modifications of their rheological properties. The mechanisms of development of such processes at work during diagenesis, metamorphism or fault differentiation are poorly known as they are not easy to reproduce in the laboratory due to the long duration required for most of chemically controlled differentiation processes. Here we show that experimental compaction with layering development, similar to what happens in natural deformation, can be obtained in the laboratory by indenter techniques. Samples of plaster mixed with clay and samples of diatomite loosely interbedded with clays were loaded during several months at 40°C (plaster) and 150°C (diatomite) in presence of their saturated solutions. High-resolution X-ray tomography and SEM studies show that the layering development is a self-organized process. Stress driven dissolution of the soluble minerals (gypsum in plaster, silica in diatomite) is initiated in the zones initially richer in clays because the kinetics of diffusive mass transfer along the clay/soluble mineral interfaces is much faster than along the healed boundaries of the soluble minerals. The passive concentration of the clay minerals amplifies the localization of the dissolution along some layers oriented perpendicular to the maximum compressive stress component. Conversely, in the areas with initial low content in clay and clustered soluble minerals, dissolution is more difficult as the grain boundaries of the soluble species are healed together. These areas are less deformed and they act as rigid objects that concentrate the dissolution near their boundaries thus amplifying the differentiation. Applications to fault processes are discussed: i) localized pressure solution and sealing processes may lead to fault rheology differentiation with a partition between two end-member behaviors: seismic (in sealed zones) and aseismic (in dissolved zones); ii) tectonic layering may lead to highly anisotropic structures with a drastic decrease of the rock strength parallel to the layering.

The long-term acceleration of waste glass corrosion: A preliminary review

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kielpinski, A.L.

1995-07-01

Whereas a prior conception of glass dissolution assumed a relatively rapid initial dissolution which then slowed to a smaller, fairly constant longer-term rate, some recent work suggests that these two stages are followed by a third phase of dissolution, in which the dissolution rate is accelerated with respect to what had previously been thought of as the final long-term rate. The goals of the present study are to compile experimental data which may have a bearing on this phenomena, and to provide an initial assessment of these data. The Savannah River Technology Center (SRTC) is contracted to develop glass formulationmore » models for vitrification of Hanford low-level waste (LLW), in support of the Hanford Tank Waste Remediation System Technology Development Program. The phenomenon of an increase in corrosion rate, following a period characterized by a low corrosion rate, has been observed by a number of researchers on a number of waste glass compositions. Despite inherent ambiguities arising from SA/V (glass surface area to solution volume ratio) and other effects, valid comparisons can be made in which accelerated corrosion was observed in one test, but not in another. Some glass compositions do not appear to attain a plateau region; it may be that the observation of continued, non-negligible corrosion in these glasses represents a passage from the initial rate to the accelerated rate. The long-term corrosion is a function of the interaction between the glass and its environment, including the leaching solution and the surrounding materials. Reaction path modeling and stability field considerations have been used with some success to predict the changes in corrosion rate over time, due to these interactions. The accelerated corrosion phenomenon highlights the need for such integrated corrosion modeling and the scenario-specific nature of a particular glass composition`s durability.« less

Growth and dissolution of an encapsulated contrast microbubble: effects of encapsulation permeability

PubMed Central

Sarkar, Kausik; Katiyar, Amit; Jain, Pankaj

2009-01-01

Gas diffusion from an encapsulated microbubble is modeled using an explicit linear relation for gas permeation through the encapsulation. Both the cases of single gas (air) and multiple gases (perfluorocarbon inside the bubble and air dissolved in surrounding liquid) are considered. An analytical expression for the dissolution time for an encapsulated air bubble is obtained; it showed that for small permeability the dissolution time increases linearly with decreasing permeability. A perfluorocarbon-filled contrast microbubble such as Definity was predicted to experience a transient growth due to air infusion before it dissolves in conformity with previous experimental findings. The growth phase occurs only for bubbles with a critical value of initial partial mole fraction of perfluorocarbon relative to air. With empirically obtained property values, the dissolution time of a 2.5 micron diameter (same as that of Definity) lipid coated octafluoropropane bubble with surface tension 25 mN/m predicts a lifetime of 42 minutes in an air saturated medium. The properties such as shell permeability, surface tension, relative mole fraction of octafluoropropane are varied to investigate their effects on the time scales of bubble growth and dissolution including their asymptotic scalings where appropriate. The dissolution dynamics scales with permeability, in that when the time is nondimensioanlized with permeability, curves for different permeabilities collapse on a single curve. Investigation of bubbles filled with other gases (non-octafluoropropane perfluorocarbon and sulfur hexafluoride) indicates longer dissolution time due to lower solubility and lower diffusivity for larger gas molecules. For such micron size encapsulated bubbles, lifetime of hours is possible only at extremely low surface tension (<1mN/m) or at extreme oversaturation. PMID:19616160

The comparative analysis of heat transfer efficiency in the conditions of formation of ash deposits in the boiler furnaces, with taking into account the crystallization of slag during combustion of coal and water-coal fuel

NASA Astrophysics Data System (ADS)

Salomatov, V. V.; Kuznetsov, G. V.; Syrodoy, S. V.

2017-11-01

The results of the numerical simulation of heat transfer from the combustion products of coal and coal-water fuels (CWF) to the internal environment. The mathematical simulation has been carried out on the sample of the pipe surfaces of the combustion chamber of the boiler unit. The change in the characteristics of heat transfer (change of thermochemical characteristics) in the conditions of formation of the ash deposits have been taken into account. According to the results of the numerical simulation, the comparative analysis of the efficiency of heat transfer has been carried out from the furnace environment to the inside pipe coolant (water, air, or water vapor) from the combustion of coal and coal-water fuels. It has been established that, in the initial period of the boiler unit operation during coal fuel combustion the efficiency of heat transfer from the combustion products of the internal environment is higher than when using CWF. The efficiency of heat transfer in CWF combustion conditions is more at large times (τ≥1.5 hours) of the boiler unit. A significant decrease in heat flux from the combustion products to the inside pipe coolant in the case of coal combustion compared to CWF has been found. It has been proved that this is due primarily to the fact that massive and strong ash deposits are formed during coal combustion.

Leaching characteristics of toxic constituents from coal fly ash mixed soils under the influence of pH.

PubMed

Komonweeraket, Kanokwan; Cetin, Bora; Benson, Craig H; Aydilek, Ahmet H; Edil, Tuncer B

2015-04-01

Leaching behaviors of Arsenic (As), Barium (Ba), Calcium (Ca), Cadmium (Cd), Magnesium (Mg), Selenium (Se), and Strontium (Sr) from soil alone, coal fly ash alone, and soil-coal fly ash mixtures, were studied at a pH range of 2-14 via pH-dependent leaching tests. Seven different types of soils and coal fly ashes were tested. Results of this study indicated that Ca, Cd, Mg, and Sr showed cationic leaching pattern while As and Se generally follows an oxyanionic leaching pattern. On the other hand, leaching of Ba presented amphoteric-like leaching pattern but less pH-dependent. In spite of different types and composition of soil and coal fly ash investigated, the study reveals the similarity in leaching behavior as a function of pH for a given element from soil, coal fly ash, and soil-coal fly ash mixtures. The similarity is most likely due to similar controlling mechanisms (e.g., solubility, sorption, and solid-solution formation) and similar controlling factors (e.g., leachate pH and redox conditions). This offers the opportunity to transfer knowledge of coal fly ash that has been extensively characterized and studied to soil stabilized with coal fly ash. It is speculated that unburned carbon in off-specification coal fly ashes may provide sorption sites for Cd resulting in a reduction in concentration of these elements in leachate from soil-coal fly ash mixture. Class C fly ash provides sufficient CaO to initiate the pozzolanic reaction yielding hydrated cement products that oxyanions, including As and Se, can be incorporated into. Copyright © 2014 Elsevier Ltd. All rights reserved.

Weathering of historical copper slags in dynamic experimental system with rhizosphere-like organic acids.

PubMed

Potysz, Anna; Kierczak, Jakub; Grybos, Malgorzata; Pędziwiatr, Artur; van Hullebusch, Eric D

2018-06-01

This study was undertaken to simulate experimentally the weathering of slags disposed nearby soil rhizosphere. The aim of the research was to differentiate the effect of pH and organics on slags dissolution as well as to indicate weathering sequence of phase components. The studied slags are mainly composed of Fe (34.5 wt%) and Si (17.9 wt%) and contain up to 3761 mg kg -1 of Cu and 3628 mg kg -1 of Zn. The main identified phases are fayalite and glass, whereas sulfides and metallic Cu are volumetrically minor. A 30 days long slag weathering experiment was carried out with artificial root exudates (43.7 mM) and demineralized water at initial pH = 3.5 and pH = 6.7. The highest metal release (up to 10.9% of Zn and 4.6% of Cu) was observed in ARE solution at initial pH 3.5. Dissolution of sulfides and fayalite was mainly driven by pH. Artificial root exudates enhance glass dissolution as compared to demineralized water regardless of initially fixed pH. Based on this study following weathering sequences are delineated: i) under ARE 3.5 conditions: silicates > glass > sulfides, ii) under DW 3.5 conditions: sulfides > silicates > glass, iii) under near-neutral conditions: sulfides > glass > silicates. Copyright © 2018 Elsevier Ltd. All rights reserved.

Mathematical models as tools for probing long-term safety of CO2 storage

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pruess, Karsten; Birkholzer, Jens; Zhou, Quanlin

Subsurface reservoirs being considered for storing CO{sub 2} include saline aquifers, oil and gas reservoirs, and unmineable coal seams (Baines and Worden, 2004; IPCC, 2005). By far the greatest storage capacity is in saline aquifers (Dooley et al., 2004), and our discussion will focus primarily on CO{sub 2} storage in saline formations. Most issues for safety and security of CO{sub 2} storage arise from the fact that, at typical temperature and pressure conditions encountered in terrestrial crust, CO{sub 2} is less dense than aqueous fluids. Accordingly, CO{sub 2} will experience an upward buoyancy force in most subsurface environments, and willmore » tend to migrate upwards whenever (sub-)vertical permeable pathways are available, such as fracture zones, faults, or improperly abandoned wells (Bachu, 2008; Pruess, 2008a, b; Tsang et al., 2008). CO{sub 2} injection will increase fluid pressures in the target formation, thereby altering effective stress distributions, and potentially triggering movement along fractures and faults that could increase their permeability and reduce the effectiveness of a caprock in containing CO{sub 2} (Rutqvist et al., 2008; Chiaramonte et al., 2008). Induced seismicity as a consequence of fluid injection is also a concern (Healy et al., 1968; Raleigh et al., 1976; Majer et al., 2007). Dissolution of CO{sub 2} in the aqueous phase generates carbonic acid, which may induce chemical corrosion (dissolution) of minerals with associated increase in formation porosity and permeability, and may also mediate sequestration of CO{sub 2} as solid carbonate (Gaus et al., 2008). Chemical dissolution of caprock minerals could promote leakage of CO{sub 2} from a storage reservoir (Gherardi et al., 2007). Chemical dissolution and geomechanical effects could reinforce one another in compromising CO{sub 2} containment. Additional issues arise from the potential of CO{sub 2} to mobilize hazardous chemical species (Kharaka et al., 2006), and from migration of the large amounts of brine that would be mobilized by industrial-scale CO{sub 2} injection (Nicot et al., 2008; Birkholzer et al., 2008a, b).« less

Impact of dissolution and carbonate precipitation on carbon storage in basalt

NASA Astrophysics Data System (ADS)

Wells, R. K.; Xiong, W.; Tadeoye, J.; Menefee, A.; Ellis, B. R.; Skemer, P. A.; Giammar, D.

2016-12-01

The spatial evolution of silicate mineral dissolution, carbonate precipitation, and the transport of fluids influence the viability of carbon storage in basalt reservoirs. Dissolution of natural basalt and subsequent carbonate precipitation in systems with different transport processes operating were characterized using static and flow-through (5 mL/hr) experiments at 50, 100, and 150 °C, and 100 bar CO2. Intact samples and cores with milled pathways that simulate fractures were tested. Spatial and mineralogical patterns in dissolution and precipitation were analyzed using optical and electron microscopy, microCT scanning, and surface roughness data. Precipitates and fluid chemistry were analyzed using Raman spectroscopy, SEM-EDS, and ICP-MS. Analysis of the bulk solution and surface topography suggests dissolution of olivine and pyroxene grains begins within hours of the start of the experiments. In flow-through experiments, total effluent cation concentrations reach a peak concentration within a few hours then drop towards a steady state within a few days. In static experiments, the initial rate of cation release is faster than it is after several weeks. In both cases Ca2+, Mg2+, and Fe2+ are the dominant cations in solution in the initial stages of reaction. Lower concentrations of Na2+, K+, and Al3+, and the preservation of feldspar and matrix grains after several weeks of reaction indicate the slow reactivity of these minerals. As the reaction progresses, the surface roughness increases steadily with cavities developing at the sites of olivine and pyroxene grains. Post-reaction analysis of basalt samples reacted at static conditions with milled pathways reveals that both siderite and amorphous silica precipitated within diffusion-limited zones as early as 4-6 weeks. Siderite abundance varies with distance along the pathway with the highest concentration of carbonates 1-2 cm below the fracture opening. Siderite precipitates are large enough to fill fracture opening 100 μm wide within 4-6 weeks.

Subarctic physicochemical weathering of serpentinized peridotite

NASA Astrophysics Data System (ADS)

Ulven, O. I.; Beinlich, A.; Hövelmann, J.; Austrheim, H.; Jamtveit, B.

2017-06-01

Frost weathering is effective in arctic and subarctic climate zones where chemical reactions are limited by the reduced availability of liquid water and the prevailing low temperature. However, small scale mineral dissolution reactions are nevertheless important for the generation of porosity by allowing infiltration of surface water with subsequent fracturing due to growth of ice and carbonate minerals. Here we combine textural and mineralogical observations in natural samples of partly serpentinized ultramafic rocks with a discrete element model describing the fracture mechanics of a solid when subject to pressure from the growth of ice and carbonate minerals in surface-near fractures. The mechanical model is coupled with a reaction-diffusion model that describes an initial stage of brucite dissolution as observed during weathering of serpentinized harzburgites and dunites from the Feragen Ultramafic Body (FUB), SE-Norway. Olivine and serpentine are effectively inert at relevant conditions and time scales, whereas brucite dissolution produces well-defined cm to dm thick weathering rinds with elevated porosity that allows influx of water. Brucite dissolution also increases the water saturation state with respect to hydrous Mg carbonate minerals, which are commonly found as infill in fractures in the fresh rock. This suggests that fracture propagation is at least partly driven by carbonate precipitation. Dissolution of secondary carbonate minerals during favorable climatic conditions provides open space available for ice crystallization that drives fracturing during winter. Our model reproduces the observed cm-scale meandering fractures that propagate into the fresh part of the rock, as well as dm-scale fractures that initiate the breakup of larger domains. Rock disintegration increases the reactive surface area and hence the rate of chemical weathering, enhances transport of dissolved and particulate matter in the weathering fluid, and facilitates CO2 uptake by carbonate precipitation. Our observations have implications for element cycling and CO2 sequestration in natural gravel and mine tailings.

Underground thermal generation of hydrocarbons from dry, southwestern coals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vanderborgh, N.E.; Elliott, G.R.B.

1978-01-01

The LASL underground coal conversion concept produces intermediate-BTU fuel gas for nearby industries such as ''minemouth'' electric power plants, plus major byproducts in the form of liquid and gaseous hydrocarbons for feedstocks to chemical plants e.g., substitute natural gas (SNG) producers. The concept involves controlling the water influx and drying the coal, generating hydrocarbons, by pyrolysis and finally gasifying the residual char with O/sub 2//CO/sub 2/ or air/CO/sub 2/ mixtures to produce industrial fuel gases. Underground conversion can be frustrated by uncontrolled water in the coal bed. Moisture can (a) prevent combustion, (b) preclude fuel gas formation by lowering reactionmore » zone temperatures and creating kinetic problems, (c) ruin product gas quality by dropping temperatures into a thermodynamically unsatisfactory regime, (d) degrade an initially satisfactory fuel gas by consuming carbon monoxide, (e) waste large amounts of heat, and (f) isolate reaction zones so that the processing will bypass blocks of coal.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jones, M.L.

This paper very briefly summarizes progress in the demonstration of a small (up to 6 MWe), environmentally acceptable electric generating system fueled by indigenous fuels and waste materials to serve power distribution systems typical of Alaskan Native communities. Two detailed appendices supplement the report. The project is focused on two primary technologies: (1) atmospheric fluidized bed combustion (AFBC), and (2) coalbed methane and coal-fired diesel technologies. Two sites have been selected as possible locations for an AFBC demonstration, and bid proposals are under review. The transfer of a coal-fired diesel clean coal demonstration project from Maryland to Fairbanks, Alaska wasmore » approved, and the environmental assessment has been initiated. Federal support for a fuel cell using coalbed methane is also being pursued. The appendices included in the report provide: (1) the status of the conceptual design study for a 600-kWe coal-fired cogeneration plant in McGrath, Alaska; and (2) a global market assessment of coalbed methane, fluidized-bed combustion, and coal-fired diesel technologies in remote applications.« less

Discovery and ramifications of incidental Magnéli phase generation and release from industrial coal-burning.

PubMed

Yang, Yi; Chen, Bo; Hower, James; Schindler, Michael; Winkler, Christopher; Brandt, Jessica; Di Giulio, Richard; Ge, Jianping; Liu, Min; Fu, Yuhao; Zhang, Lijun; Chen, Yuru; Priya, Shashank; Hochella, Michael F

2017-08-08

Coal, as one of the most economic and abundant energy sources, remains the leading fuel for producing electricity worldwide. Yet, burning coal produces more global warming CO 2 relative to all other fossil fuels, and it is a major contributor to atmospheric particulate matter known to have a deleterious respiratory and cardiovascular impact in humans, especially in China and India. Here we have discovered that burning coal also produces large quantities of otherwise rare Magnéli phases (Ti x O 2x-1 with 4 ≤ x ≤ 9) from TiO 2 minerals naturally present in coal. This provides a new tracer for tracking solid-state emissions worldwide from industrial coal-burning. In its first toxicity testing, we have also shown that nanoscale Magnéli phases have potential toxicity pathways that are not photoactive like TiO 2 phases, but instead seem to be biologically active without photostimulation. In the future, these phases should be thoroughly tested for their toxicity in the human lung.Solid-state emissions from coal burning remain an environmental concern. Here, the authors have found that TiO2 minerals present in coal are converted into titanium suboxides during burning, and initial biotoxicity screening suggests that further testing is needed to look into human lung consequences.

CO(2), CO, and Hg emissions from the Truman Shepherd and Ruth Mullins coal fires, eastern Kentucky, USA.

PubMed

O'Keefe, Jennifer M K; Henke, Kevin R; Hower, James C; Engle, Mark A; Stracher, Glenn B; Stucker, J D; Drew, Jordan W; Staggs, Wayne D; Murray, Tiffany M; Hammond, Maxwell L; Adkins, Kenneth D; Mullins, Bailey J; Lemley, Edward W

2010-03-01

Carbon dioxide (CO(2)), carbon monoxide (CO), and mercury (Hg) emissions were quantified for two eastern Kentucky coal-seam fires, the Truman Shepherd fire in Floyd County and the Ruth Mullins fire in Perry County. This study is one of the first to estimate gas emissions from coal fires using field measurements at gas vents. The Truman Shepherd fire emissions are nearly 1400t CO(2)/yr and 16kg Hg/yr resulting from a coal combustion rate of 450-550t/yr. The sum of CO(2) emissions from seven vents at the Ruth Mullins fire is 726+/-72t/yr, suggesting that the fire is consuming about 250-280t coal/yr. Total Ruth Mullins fire CO and Hg emissions are estimated at 21+/-1.8t/yr and >840+/-170g/yr, respectively. The CO(2) emissions are environmentally significant, but low compared to coal-fired power plants; for example, 3.9x10(6)t CO(2)/yr for a 514-MW boiler in Kentucky. Using simple calculations, CO(2) and Hg emissions from coal-fires in the U.S. are estimated at 1.4x10(7)-2.9x10(8)t/yr and 0.58-11.5t/yr, respectively. This initial work indicates that coal fires may be an important source of CO(2), CO, Hg and other atmospheric constituents.

A preliminary review of coal exploration activities conducted by the government of Armenia and the coal resource potential of Armenia

USGS Publications Warehouse

Warwick, Peter D.; Pierce, B.S.; Landis, E.R.

1993-01-01

A coal resource assessment team from the U.S. Geological Survey (USGS), in cooperation with the Armenian Department of Underground Resources (DUR) and elements of the Ministry of Energy and Fuel, has completed an initial visit to Armenia under the auspices of the U.S. Agency for International Development JUSAID). The visit included discussions of the coal resources, identification of problems associated with on-going exploration and development activities, and field visits to selected solid fuel areas. The USGS team will return in November with a draft of the final report for discussion of conclusions and recommendations with Armenian counterparts, representatives of USAID, and the American Embassy. The final report, which will contain tabulated coal-sample analytical results and detailed recommendations, will be submitted to the USAID by the end of December 1993.Preliminary conclusions are that: 1) Armenia has usable deposits of coal that could form a viable, though relatively small, component of Armenia's energy budget; 2) on-going exploration and development activities must be augmented and expedited to increase understanding of the coal resource potential and subsequent utilization; 3) deficiencies in supplies (primarily fuel) and equipment (replacement of aging parts and units) have greatly reduced the gathering of necessary resource data; and 4) training of Armenian counterparts in conducting and managing coal exploration activities is desirable.

Fayalite Dissolution and Siderite Formation in Water-Saturated Supercritical CO2

DOE Office of Scientific and Technical Information (OSTI.GOV)

Qafoku, Odeta; Kovarik, Libor; Kukkadapu, Ravi K.

2012-11-25

Olivines, a significant constituent of basaltic rocks, have the potential to immobilize permanently CO2 after it is injected in the deep subsurface, due to carbonation reactions occurring between CO2 and the host rock. To investigate the reactions of fayalitic olivine with supercritical CO2 (scCO2) and formation of mineral carbonates, experiments were conducted at temperatures of 35 °C to 80 °C, 90 atm pressure and anoxic conditions. For every temperature, the dissolution of fayalite was examined both in the presence of liquid water and H2O-saturated scCO2. The experiments were conducted in a high pressure batch reactor at reaction time extending upmore » to 85 days. The newly formed products were characterized using a comprehensive suite of bulk and surface characterization techniques X-ray diffraction, Transmission/Emission Mössbauer Spectroscopy, Scanning Electron Microscopy coupled with Focused Ion Beam, and High Resolution Transmission Electron Microscopy. Siderite with rhombohedral morphology was formed at 35 °C, 50 °C, and 80 °C in the presence of liquid water and scCO2. In H2O-saturated scCO2, the formation of siderite was confirmed only at high temperature (80 °C). Characterization of reacted samples in H2O-saturated scCO2 with high resolution TEM indicated that siderite formation initiated inside voids created during the initial steps of fayalite dissolution. Later stages of fayalite dissolution result in the formation of siderite in layered vertical structures, columns or pyramids with a rhombus base morphology.« less

Facies development in the Lower Freeport coal bed, west-central Pennsylvania, U.S.A.

USGS Publications Warehouse

Pierce, B.S.; Stanton, R.W.; Eble, C.F.

1991-01-01

The Lower Freeport coal bed in west-central Pennsylvania is interpreted to have formed within a lacustrine-mire environment. Conditions of peat formation, caused by the changing chemical and physical environments, produced five coal facies and two mineral-rich parting facies within the coal bed. The coal bed facies are compositionally unique, having developed under varying conditions, and are manifested by megascopic, petrographic, palynologic and quality characteristics. The initial environment of the Lower Freeport peat resulted in a coal facies that is relatively high in ash yield and contains large amounts of lycopod miospores and moderate abundances of cryptotelinite, crypto-gelocollinite, inertinite and tree fern miospores. This initial Lower Freeport peat is interpreted to have been a topogenous body that was low lying, relatively nutrient rich (mesotrophic to eutrophic), and susceptible to ground water and to sediment influx from surface water. The next facies to form was a ubiquitous, clay-rich durain parting which is attributed to a general rise in the water table accompanied by widespread flooding. Following formation of the parting, peat accumulation resumed within an environment that inhibited clastic input. Development of doming in this facies restricted deposition of the upper shale parting to the margins of the mire and allowed low-ash peat to form in the interior of the mire. Because this environment was conducive to preservation of cellular tissue, this coal facies also contains large amounts of crypto-telinite. This facies development is interpreted to have been a transitional phase from topogenous, planar peat formation to slightly domed, oligotrophic (nutrient-poor) peat formation. As domed peat formation continued, fluctuations in the water table enabled oxidation of the peat surface and produced high inertinite concentrations toward the top of the coal bed. Tree ferns became an increasingly important peat contributor in the e upper facies, based on the palynoflora. This floral change is interpreted to have resulted from the peat surface becoming less wet or better drained, a condition that inhibited proliferation of lycopod trees. Accumulation of the peat continued until rising water levels formed a freshwater lake within which clays and silts were deposited. The development of the Lower Freeport peat from a planar mire through transitional phases toward domed peat formation may be an example of the type of peat formation of other upper Middle and Upper Pennsylvanian coal beds. ?? 1991.

Installation of a stoker-coal preparation plant in Krakow, Poland. Quarterly technical progress report No. 4, January--March, 1995

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rozelle, P.

1996-01-01

This report describes the progress made during this reporting period of a two year project to demonstrate that the air pollution from a traveling-grate stoker being used to heat water at a central heating plant in Krakow, Poland can be reduced significantly by (1) substituting the unwashed, unsized coal currently being used with a mechanically cleaned, double-sized stoker fuel and by (2) optimizing the operating parameters of the stoker. It is anticipated that these improvements will prove to be cost-effective and hence will be adopted by the other central heating plants in Krakow and ideally, throughout Eastern European cities wheremore » coal continues to be the primary source of fuel. EFH Coal Company has formed a partnership with two Polish institutions -- MPEC, a central heating company in Krakow, and Naftokrak-Naftobudowa, preparation plant designers and fabricators-for the execution of this effort. Five potential candidate sources have been located and contracts for coal deliveries should be executed early next quarter. TInitial delays in formalizing the EFH/Polish Partners agreement delayed finalizing the coal supply contracts and hence, precluded collecting the Polish coal samples for characterization and combustion performance studies. Work on this Task will be initialed next quarter after the raw coal supply contracts are executed. A conceptual design for a plant to wash 25mm x 0 raw coal fines at a need rate of 300 mtph was completed. This plant will receive raw coals ranging in ash content from 20 to 30 percent and produce a compliance coal containing about 1 percent ash, 0.8 percent sulfur and 27, 840 KJ/kg (12,000 Btu/lb). A heavy-media cyclone will be used to wash the 20mm x 1mm stoker coal. Discussions with financial institutions regarding the cost of producing a quality stoker coal in Poland and A for identifying sources of private capital to help cost share the project continued.« less

Characterization of airborne float coal dust emitted during continuous mining, longwall mining and belt transport

PubMed Central

Shahan, M.R.; Seaman, C.E.; Beck, T.W.; Colinet, J.F.; Mischler, S.E.

2017-01-01

Float coal dust is produced by various mining methods, carried by ventilating air and deposited on the floor, roof and ribs of mine airways. If deposited, float dust is re-entrained during a methane explosion. Without sufficient inert rock dust quantities, this float coal dust can propagate an explosion throughout mining entries. Consequently, controlling float coal dust is of critical interest to mining operations. Rock dusting, which is the adding of inert material to airway surfaces, is the main control technique currently used by the coal mining industry to reduce the float coal dust explosion hazard. To assist the industry in reducing this hazard, the Pittsburgh Mining Research Division of the U.S. National Institute for Occupational Safety and Health initiated a project to investigate methods and technologies to reduce float coal dust in underground coal mines through prevention, capture and suppression prior to deposition. Field characterization studies were performed to determine quantitatively the sources, types and amounts of dust produced during various coal mining processes. The operations chosen for study were a continuous miner section, a longwall section and a coal-handling facility. For each of these operations, the primary dust sources were confirmed to be the continuous mining machine, longwall shearer and conveyor belt transfer points, respectively. Respirable and total airborne float dust samples were collected and analyzed for each operation, and the ratio of total airborne float coal dust to respirable dust was calculated. During the continuous mining process, the ratio of total airborne float coal dust to respirable dust ranged from 10.3 to 13.8. The ratios measured on the longwall face were between 18.5 and 21.5. The total airborne float coal dust to respirable dust ratio observed during belt transport ranged between 7.5 and 21.8. PMID:28936001

USA's Black Thunder mine: a truck and shovel operation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dorling, I.

During 1966/1967, ARCO obtained over 2,631 hectares (6,500 acres) of federal and state coal leases, and initial exploration was started. A total of 312 coal core holes were drilled and logged to determine the reserves and quality of the coal. The results indicated that a large surface mine could be developed to exploit the substantial reserves. The application procedure for permits was started early in 1974. Thunder Basin Coal Company is mining the Wyodak-Anderson Seam where the coal is about 21 meters (69 feet) thick. It has been estimated that a total of 750,000,000 tons of coal exist with amore » 0.3 to 0.4 percent sulfur content and a heating value of about 8,600 Btu per pound. The seam is mined in one lift using electric shovels and trucks. There are many factors which govern the choice of either a dragline or a truck and shovel operation for removing overburden. At the Black Thunder mine the conditions which favored the choice of the truck and shovel method were topography and pit geometry. The run-of-mine coal is dumped into two 540-ton hoppers. Underground vibrating grizzly feeders (2,500 tph capacity) pass the coal into 2,500 tph primary single-roll crushers, where the ROM coal is reduced to minus 8 inches. A 72-inch-wide elevating conveyor carries the coal to a 110-ton surge hopper, and is then fed into two secondary crushers where the coal is further reduced to minus-2 inches. The system is able to handle 5,000 tons of ROM coal per hour. The total production of coal from the mine in 1978 is expected to be about 3,000,000 tons, depending on customer requirements. It is expected that in 1979 the output will rise to 8,000,000 tons, and by 1983 the full planned production of 20,000,000 tons a year will be reached. (LTN)« less

Electromagnetic wave method for mapping subterranean earth formations

DOEpatents

Shuck, Lowell Z.; Fasching, George E.; Balanis, Constantine A.

1977-01-01

The present invention is directed to a method for remotely mapping subterranean coal beds prior to and during in situ gasification operations. This method is achieved by emplacing highly directional electromagnetic wave transmitters and receivers in bore holes penetrating the coal beds and then mapping the anomalies surrounding each bore hole by selectively rotating and vertically displacing the directional transmitter in a transmitting mode within the bore hole, and thereafter, initiating the gasification of the coal at bore holes separate from those containing the transmitters and receivers and then utilizing the latter for monitoring the burn front as it progresses toward the transmitters and receivers.

Development of a Physiologically Relevant Population Pharmacokinetic in Vitro-in Vivo Correlation Approach for Designing Extended-Release Oral Dosage Formulation.

PubMed

Kim, Tae Hwan; Shin, Soyoung; Bulitta, Jürgen B; Youn, Yu Seok; Yoo, Sun Dong; Shin, Beom Soo

2017-01-03

Establishing a level A in vitro-in vivo correlation (IVIVC) for a drug with complex absorption kinetics is challenging. The objective of the present study was to develop an IVIVC approach based on population pharmacokinetic (POP-PK) modeling that incorporated physiologically relevant absorption kinetics. To prepare three extended release (ER) tablets of loxoprofen, three types of hydroxypropyl methylcellulose (HPMC 100, 4000, and 15000 cps) were used as drug release modifiers, while lactose and magnesium stearate were used as the diluent and lubricant, respectively. An in vitro dissolution test in various pH conditions showed that loxoprofen dissolution was faster at higher pH. The in vivo pharmacokinetics of loxoprofen was assessed following oral administration of the different loxoprofen formulations to Beagle dogs (n = 22 in total). Secondary peaks or shoulders were observed in many of the individual plasma concentration vs time profiles after ER tablet administration, which may result from secondary absorption in the intestine due to a dissolution rate increase under intestinal pH compared to that observed at stomach pH. In addition, in vivo oral bioavailability was found to decrease with prolonged drug dissolution, indicating site-specific absorption. Based on the in vitro dissolution and in vivo absorption data, a POP-PK IVIVC model was developed using S-ADAPT software. pH-dependent biphasic dissolution kinetics, described using modified Michaelis-Menten kinetics with varying V max , and site-specific absorption, modeled using a changeable absorbed fraction parameter, were applied to the POP-PK IVIVC model. To experimentally determine the biphasic dissolution profiles of the ER tablets, another in vitro dissolution test was conducted by switching dissolution medium pH based on an in vivo estimate of gastric emptying time. The model estimated, using linear regression, that in vivo initial maximum dissolution rate (V max (0) in vivo ) was highly correlated (r 2 > 0.998) with in vitro (V max (0) in vitro ), indicating that in vivo dissolution profiles obtained from POP-PK modeling could be converted to in vitro dissolution profiles and vice versa. Monte Carlo simulations were performed for model validation, and prediction errors for C max and AUC were all within the acceptable range (90 to 110%) according to the FDA guidelines. The developed model was successfully applied for the prediction of in vivo pharmacokinetics of a loxoprofen double-layered tablet using the in vitro dissolution profile. In conclusion, a level A IVIVC approach was developed and validated using population modeling that accounted for pH-dependent dissolution and site-specific absorption. Excellent correlations were observed between in vitro and in vivo dissolution profiles. This new approach holds great promise for the establishment of IVIVCs for drug and formulation development where absorption kinetics strongly depend on complex physiologically absorption processes.

Thermodynamic Aspects of the Formation of Sulfate Minerals from Hot Gaseous Phase

NASA Astrophysics Data System (ADS)

Giere, R.; Majzlan, J.

2006-12-01

Minerals may form by solid-state reactions or by dissolution and precipitation from a fluid phase, be it magma, aqueous medium, or gas. The latter phase was traditionally not considered as important as the other ones, although it may be essential in some geological environments. Components of minerals (e.g., sulfur) are commonly transported by hot gases in volcanoes. Others may form in burning coal dumps or by burning fossil fuels for energy production. We have identified a number of minerals which precipitated from the hot gases escaping into the atmosphere from the smoke stack of a coal-fired power plant. This power plant uses coal or a mixture of coal and used tires to produce electricity. The phases identified by TEM are anglesite (PbSO4), gunningite (ZnSO4?H2O), anhydrite (CaSO4), and yavapaiite (KFe(SO4)2). In addition to these crystalline phases, amorphous sulfate materials and soot have been identified. All these materials were captured by filtering the escaping gases beyond the last filters intended to remove any particles from the gas stream. Therefore, they must have formed by precipitation from the hot gas and may present a significant pollution load in the vicinity of power plants. Verhulst et al. (1996) have shown that several metals are most likely transported as chloride complexes in the gas phase. Their assumption correlates well with the finding that the chloride-richer coal+tire mixture increases considerably amounts of emitted metals. Using thermodynamic data for these and other sulfate minerals, we are trying to understand and model the precipitation process of these minerals from hot gases at ambient pressures. In this contribution, we focus on the mineral mikasaite (trigonal Fe2(SO4)3). This mineral has been reported only from burning coal dumps (Miura et al. 1994). Using acid-solution calorimetry, we have determined the enthalpy of formation of mikasaite from elements at T = 298.15 K. We have further estimated the standard entropy of this mineral. Using the measured and estimated thermodynamic data for mikasaite and the published data for Fe-Cl complexes, we will present equilibrium diagrams for the Fe2O3-H2O-SO2-HCl system. In future, we are aiming at developing a thermodynamic database for the minerals found to precipitate from hot gases at burning coal dumps, power plants, and volcanic fumaroles. Verhulst, D., Buekens, A., Spencer, P., Eriksson, G., 1996: Thermodynamic behavior of metal chlorides and sulfates under the conditions of incineration furnaces. Environmental Science and Technology 30, 50-56. Miura H, Niida K, Hirama T, 1994: Mikasaite, (Fe3+, Al)2(SO4)3, a new ferric sulfate mineral from Mikasa City, Hokkaido, Japan. Mineralogical Magazine 58, 649-653.

Studies of angiospermous wood in Australian brown coal by nuclear magnetic resonance and analytical pyrolysis: new insights into the early coalification process

USGS Publications Warehouse

Hatcher, P.G.; Wilson, M.A.; Vassallo, A.M.; Lerch, H. E.

1989-01-01

Many Tertiary coals contain abundant fossilized remains of angiosperms, which commonly dominated the ancient peat-swamp environments; modern analogs of such swamps can be found in tropical and subtropical regions of the world. Comparisons of angiospermous wood from Australian brown coal with similar wood buried in modern peat swamps of Indonesia have provided some new insights into coalification reactions. These comparisons were made by using solid-state 13C nuclear magnetic resonance (NMR) techniques and pyrolsis-gas chromatography-mass spectrometry (py-gc-ms). These two modern techniques are especially suited for detailed structural evaluation of the complex macromolecules in coal. The earliest transformation (peatification) of organic matter in angiospermous wood is the degradation and removal of cellulosic components and the concomitant selective preservation of lignin-derived components. The angiospermous lignin that becomes enriched in wood as a result of cellulose degradation also is modified by coalification reactions; this modification, however, does not involve degradation and removal of the lignin. Rather, the early coalification process transforms the lignin phenols (guiacyl and syringyl) to eventually yield the aromatic structures typically found in brown coal. One such transformation, which is determined from NMR data, involves the cleavage of aryl-ether bonds that link guaiacyl and syringyl units in lignin, and this transformation leads to the formation of free lignin phenols. Another transformation, which is also determined from the NMR data, involves the loss of methoxyl groups, probably via demethylation, to produce catechol-like structures. Coincident with ether-cleavage and demethylation, the aromatic rings derived from lignin phenols become more carbon-substituted and cross linked, as determined by dipolar-dephasing NMR studies. This cross linking is probably responsible for preventing the lignin phenols, which are freed from the lignin macromolecule by ether cleavage, from being removed from the coal by dissolution. Pyrolysis data suggest that the syringyl units are altered more readily than are guaiacyl units, and this difference in resistance leads to an enrichment of the guaiacyl units in fossil angiospermous woods. Many of the coalification reactions noted above occur to some degree in all angiospermous fossil wood examined; however, some significant differences are observed in the degree of coalification of the fossil wood samples from the same burial depth in the brown coal. These differences indicate that the depth and duration of burial are probably not entirely responsible for the variations in degree of coalification. Different rates of degradation in peat may have contributed to the variations in the apparent degree of coalification; some woods may have been altered more rapidly at the peat stage than others. Although preliminary, this systematic study of botanically related wood in peat and coal results in a more detailed differentiation of coalification reactions than have previous investigations. The combined use of solid-state 13C NMR and py-gc-ms has facilitated this detailed insight into the coalification of angiospermous wood. ?? 1989.

Research and development to prepare and characterize robust coal/biomass mixtures for direct co-feeding into gasification systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Felix, Larry; Farthing, William; Hoekman, S. Kent

This project was initiated on October 1, 2010 and utilizes equipment and research supported by the Department of Energy, National Energy Technology Laboratory, under Award Number DE- FE0005349. It is also based upon previous work supported by the Department of Energy, National Energy Technology Laboratory, under Award Numbers DOE-DE-FG36-01GOl1082, DE-FG36-02G012011 or DE-EE0000272. The overall goal of the work performed was to demonstrate and assess the economic viability of fast hydrothermal carbonization (HTC) for transforming lignocellulosic biomass into a densified, friable fuel to gasify like coal that can be easily blended with ground coal and coal fines and then be formedmore » into robust, weather-resistant pellets and briquettes.« less

Illinois basin coal fly ashes. 1. Chemical characterization and solubility

USGS Publications Warehouse

Roy, W.R.; Griffin, R.A.; Dickerson, D.R.; Schuller, R.M.; Martin, S.M.C.

1984-01-01

Twelve precipitator-collected fly ash samples (nine derived from high-sulfur Illinois Basin coals and three from Western U.S. coals) were found to contain a variety of paraffins, aryl esters, phenols, and polynuclear aromatic hydrocarbons including phenanthrene, pyrene, and chrysene but all at very low concentrations. Less than 1% of the organic carbon in the samples was extractable into benzene. Solubility studies with a short-term (24-h) extraction procedure and a long-term (20-week) procedure indicate that the inorganic chemical composition of some types of fly ash effluent is time dependent and may be most toxic to aquatic ecosystems when initially mixed with water and pumped to disposal ponds. Some acidic, high-Cd fly ashes would be classified as hazardous wastes if coal ash was included in this waste category by future RCRA revisions. ?? 1984 American Chemical Society.

Distribution law of temperature changes during methane adsorption and desorption in coal using infrared thermography technology

NASA Astrophysics Data System (ADS)

Zhao, Dong; Chen, Hao; An, Jiangfei; Zhou, Dong; Feng, Zengchao

2018-05-01

Gas adsorption and desorption is a thermodynamic process that takes place within coal as temperature changes and that is related to methane (CH4) storage. As infrared thermographic technology has been applied in this context to measure surface temperature changes, the aim of this research was to further elucidate the distribution law underlying this process as well as the thermal effects induced by heat adsorption and desorption in coal. Specimens of two different coal ranks were used in this study, and the surface temperature changes seen in the latter were detected. A contour line map was then drawn on the basis of initial results enabling a distribution law of temperature changes for samples. The results show that different regions of coal sample surfaces exhibit different heating rates during the adsorption process, but they all depends on gas storage capacity to a certain extent. It proposes a correlation coefficient that expresses the relationship between temperature change and gas adsorption capacity that could also be used to evaluate the feasibility of coalbed CH4 extraction in the field. And finally, this study is deduced a method to reveal the actual adsorption capacity of coal or CH4 reservoirs in in situ coal seams.

Mortality in an extended follow-up of British coal workers

NASA Astrophysics Data System (ADS)

MacCalman; L; Miller; G, B.

2009-02-01

The Pneumoconiosis Field Research (PFR) programme was established in the 1950s, to evaluate effects of coal mining exposures on the health and mortality of British coal workers. Surveys of working miners were carried out at 5-yearly intervals, initially in 24 collieries but later concentrating on 10, collecting detailed work histories and health information for each recruit. Here we report on cause-specific mortality in a cohort of almost 18,000 men from 10 British collieries, followed up for periods up to 47 years, yielding over 516,000 life-years of follow-up. External analyses compared cause-specific death rates in the cohort to those of the population of the regions in which the collieries were situated, using Standardised Mortality Ratios (SMRs). The causes investigated included lung cancer, stomach cancer, non-malignant respiratory disorders and cardiovascular disorders. SMRs showed evidence of an initial healthy worker effect diminishing over time. Several causes, including non-malignant respiratory disease and lung cancer, showed a significant deficit of mortality at the start of the study period with an excess in the latter part of the follow-up period. In these results, effects of working conditions are likely to be confounded with smoking habits. Overall, we believe our results may be generalised to the British coal industry since nationalisation.

Silicosis and coal workers' pneumoconiosis.

PubMed Central

Castranova, V; Vallyathan, V

2000-01-01

Exposure to coal mine dust and/or crystalline silica results in pneumoconiosis with initiation and progression of pulmonary fibrosis. This review presents characteristics of simple and complicated coal workers' pneumoconiosis (CWP) as well as pathologic indices of acute and chronic silicosis by summarizing results of in vitro, animal, and human investigations. These results support four basic mechanisms in the etiology of CWP and silicosis: a) direct cytotoxicity of coal dust or silica, resulting in lung cell damage, release of lipases and proteases, and eventual lung scarring; b) activation of oxidant production by pulmonary phagocytes, which overwhelms the antioxidant defenses and leads to lipid peroxidation, protein nitrosation, cell injury, and lung scarring; c) activation of mediator release from alveolar macrophages and epithelial cells, which leads to recruitment of polymorphonuclear leukocytes and macrophages, resulting in the production of proinflammatory cytokines and reactive species and in further lung injury and scarring; d) secretion of growth factors from alveolar macrophages and epithelial cells, stimulating fibroblast proliferation and eventual scarring. Results of in vitro and animal studies provide a basis for proposing these mechanisms for the initiation and progression of pneumoconiosis. Data obtained from exposed workers lend support to these mechanisms. Images Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 PMID:10931786

Depositional controls on coal distribution and quality in the Eocene Brunner Coal Measures, Buller Coalfield, South Island, New Zealand

USGS Publications Warehouse

Flores, R.M.; Sykes, R.

1996-01-01

The Buller Coalfield on the West Coast of the South Island, New Zealand, contains the Eocene Brunner Coal Measures. The coal measures unconformably overlie Paleozoic-Cretaceous basement rocks and are conformably overlain by, and laterally interfinger with, the Eocene marine Kaiata Formation. This study examines the lithofacies frameworks of the coal measures in order to interpret their depositional environments. The lower part of the coal measures is dominated by conglomeratic lithofacies that rest on a basal erosional surface and thicken in paleovalleys incised into an undulating peneplain surface. These lithofacies are overlain by sandstone, mudstone and organic-rich lithofacies of the upper part of the coal measures. The main coal seam of the organic-rich lithofacies is thick (10-20 m), extensive, locally split, and locally absent. This seam and associated coal seams in the Buller Coalfield are of low- to high-volatile bituminous rank (vitrinite reflectance between 0.65% and 1.75%). The main seam contains a variable percentage of ash and sulphur. These values are related to the thickening and areal distribution of the seam, which in turn, were controlled by the nature of clastic deposition and peat-forming mire systems, marine transgression and local tidal incursion. The conglomeratic lithofacies represent deposits of trunk and tributary braided streams that rapidly aggraded incised paleovalleys during sea-level stillstands. The main seam represents a deposit of raised mires that initially developed as topogenous mires on abandoned margins of inactive braidbelts. Peat accumulated in mires as a response to a rise in the water table, probably initially due to gradual sea-level rise and climate, and the resulting raised topography served as protection from floods. The upper part of the coal measures consists of sandstone lithofacies of flu vial origin and bioturbated sandstone, mudstone and organic-rich lithofacies, which represent deposits of paralic (deltaic, barrier shoreface, tidal and mire) and marine environments. The fluvial sandstone lithofacies accumulated in channels during a sea-level stillstand. The channels were infilled by coeval braided and meandering streams prior to transgression. Continued transgression, ranging from tidal channel-estuarine incursions to widespread but uneven paleoshoreline encroachment, accompanied by moderate basin subsidence, is marked by a stacked, back-stepping geometry of bioturbated sandstone and marine mudstone lithofacies. Final retrogradation (sea-level highstand) is marked by backfilling of estuaries and by rapid landward deposition of the marine Kaiata Formation in the late Eocene.

Formulation Predictive Dissolution (fPD) Testing to Advance Oral Drug Product Development: an Introduction to the US FDA Funded '21st Century BA/BE' Project.

PubMed

Hens, Bart; Sinko, Patrick; Job, Nicholas; Dean, Meagan; Al-Gousous, Jozef; Salehi, Niloufar; Ziff, Robert M; Tsume, Yasuhiro; Bermejo, Marival; Paixão, Paulo; Brasseur, James G; Yu, Alex; Talattof, Arjang; Benninghoff, Gail; Langguth, Peter; Lennernäs, Hans; Hasler, William L; Marciani, Luca; Dickens, Joseph; Shedden, Kerby; Sun, Duxin; Amidon, Gregory E; Amidon, Gordon L

2018-06-23

Over the past decade, formulation predictive dissolution (fPD) testing has gained increasing attention. Another mindset is pushed forward where scientists in our field are more confident to explore the in vivo behavior of an oral drug product by performing predictive in vitro dissolution studies. Similarly, there is an increasing interest in the application of modern computational fluid dynamics (CFD) frameworks and high-performance computing platforms to study the local processes underlying absorption within the gastrointestinal (GI) tract. In that way, CFD and computing platforms both can inform future PBPK-based in silico frameworks and determine the GI-motility-driven hydrodynamic impacts that should be incorporated into in vitro dissolution methods for in vivo relevance. Current compendial dissolution methods are not always reliable to predict the in vivo behavior, especially not for biopharmaceutics classification system (BCS) class 2/4 compounds suffering from a low aqueous solubility. Developing a predictive dissolution test will be more reliable, cost-effective and less time-consuming as long as the predictive power of the test is sufficiently strong. There is a need to develop a biorelevant, predictive dissolution method that can be applied by pharmaceutical drug companies to facilitate marketing access for generic and novel drug products. In 2014, Prof. Gordon L. Amidon and his team initiated a far-ranging research program designed to integrate (1) in vivo studies in humans in order to further improve the understanding of the intraluminal processing of oral dosage forms and dissolved drug along the gastrointestinal (GI) tract, (2) advancement of in vitro methodologies that incorporates higher levels of in vivo relevance and (3) computational experiments to study the local processes underlying dissolution, transport and absorption within the intestines performed with a new unique CFD based framework. Of particular importance is revealing the physiological variables determining the variability in in vivo dissolution and GI absorption from person to person in order to address (potential) in vivo BE failures. This paper provides an introduction to this multidisciplinary project, informs the reader about current achievements and outlines future directions. Copyright © 2018. Published by Elsevier B.V.

Ultrasonic extraction of arsenic and selenium from rocks associated with mountaintop removal/valley fills coal mining: Estimation of bioaccessible concentrations.

PubMed

Pumure, I; Renton, J J; Smart, R B

2010-03-01

Ultrasonic extraction (UE) was used to estimate the total bioaccessible fractions of arsenic and selenium released from rocks associated with mountaintop removal/valley fill coal mining. The combined readily bioaccessible amounts of arsenic and selenium in water soluble, exchangeable and NaOH fractions can be extracted from the solid phase within a 20 or 25 min application of 200 W cm(-2) ultrasound energy in nanopure water for selenium and arsenic, respectively. Application of a two-way ANOVA predicted that there are no significant differences (p0.001, n=12) in the extracted arsenic and selenium concentrations between the combined bioaccessible and ultrasonic extracts. The mechanisms for the UE of arsenic and selenium are thought to involve the formation of secondary minerals on the particle surfaces which eventually dissolve with continued sonication. This is supported by the presence of transient Si-O stretching and OH absorption and bending ATR-FTIR peaks at 795.33 cm(-1), 696.61 cm(-1) and 910.81 cm(-1). The subsequent dissolution of secondary minerals is followed by the release of chemical species that include selenium and arsenic. Release rates decrease after the ultrasound energy elastic limit for the particles is reached. Selenium and arsenic are bound differently within the rock lattice because no selenium was detected in the acid soluble fraction and no arsenic was found in the exchangeable fraction. However, selenium was found in the exchangeable fraction and arsenic was found in the acid soluble fraction. The characterization of coal associated rocks is essential to the design of methodologies and procedures that can be used to control the release of arsenic and selenium from valley fills. Published by Elsevier Ltd.

Coal fly ash interaction with environmental fluids: Geochemical and strontium isotope results from combined column and batch leaching experiments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brubaker, Tonya M; Stewart, Brian W; Capo, Rosemary C

2013-05-01

The major element and Sr isotope systematics and geochemistry of coal fly ash and its interactions with environmental waters were investigated using laboratory flow-through column leaching experiments (sodium carbonate, acetic acid, nitric acid) and sequential batch leaching experiments (water, acetic acid, hydrochloric acid). Column leaching of Class F fly ash samples shows rapid release of most major elements early in the leaching procedure, suggesting an association of these elements with soluble and surface bound phases. Delayed release of certain elements (e.g., Al, Fe, Si) signals gradual dissolution of more resistant silicate or glass phases as leaching continues. Strontium isotope resultsmore » from both column and batch leaching experiments show a marked increase in {sup 87}Sr/{sup 86}Sr ratio with continued leaching, yielding a total range of values from 0.7107 to 0.7138. For comparison, the isotopic composition of fluid output from a fly ash impoundment in West Virginia falls in a narrow range around 0.7124. The experimental data suggest the presence of a more resistant, highly radiogenic silicate phase that survives the combustion process and is leached after the more soluble minerals are removed. Strontium isotopic homogenization of minerals in coal does not always occur during the combustion process, despite the high temperatures encountered in the boiler. Early-released Sr tends to be isotopically uniform; thus the Sr isotopic composition of fly ash could be distinguishable from other sources and is a useful tool for quantifying the possible contribution of fly ash leaching to the total dissolved load in natural surface and ground waters.« less

Geochemical assessments and classification of coal mine spoils for better understanding of potential salinity issues at closure.

PubMed

Park, Jin Hee; Li, Xiaofang; Edraki, Mansour; Baumgartl, Thomas; Kirsch, Bernie

2013-06-01

Coal mining wastes in the form of spoils, rejects and tailings deposited on a mine lease can cause various environmental issues including contamination by toxic metals, acid mine drainage and salinity. Dissolution of salt from saline mine spoil, in particular, during rainfall events may result in local or regional dispersion of salts through leaching or in the accumulation of dissolved salts in soil pore water and inhibition of plant growth. The salinity in coal mine environments is from the geogenic salt accumulations and weathering of spoils upon surface exposure. The salts are mainly sulfates and chlorides of calcium, magnesium and sodium. The objective of the research is to investigate and assess the source and mobility of salts and trace elements in various spoil types, thereby predicting the leaching behavior of the salts and trace elements from spoils which have similar geochemical properties. X-ray diffraction analysis, total digestion, sequential extraction and column experiments were conducted to achieve the objectives. Sodium and chloride concentrations best represented salinity of the spoils, which might originate from halite. Electrical conductivity, sodium and chloride concentrations in the leachate decreased sharply with increasing leaching cycles. Leaching of trace elements was not significant in the studied area. Geochemical classification of spoil/waste defined for rehabilitation purposes was useful to predict potential salinity, which corresponded with the classification from cluster analysis based on leaching data of major elements. Certain spoil groups showed high potential salinity by releasing high sodium and chloride concentrations. Therefore, the leaching characteristics of sites having saline susceptible spoils require monitoring, and suitable remediation technologies have to be applied.

Ground-water contamination at an inactive coal and oil gasification plant site, Gas Works Park, Seattle, Washington

USGS Publications Warehouse

Turney, G.L.; Goerlitz, D.F.

1989-01-01

Gas Works Park, in Seattle, Washington, is located on the site of a coal and oil gasification plant that ceased operation in 1956. During operation, many types of wastes, including coal, tar, and oil, accumulated on site. The park soil is presently (1986) contaminated with compounds such as polynuclear aromatic hydrocarbons, volatile organic compounds, trace metals, and cyanide. Analyses of water samples from a network of observation wells in the park indicate that these compounds are also present in the groundwater. Polynuclear aromatic hydrocarbons and volatile organic compounds were identified in groundwater samples in concentrations as large as 200 mg/L. Concentrations of organic compounds were largest where groundwater was in contact with a nonaqueous phase liquid in the soil. Concentrations in groundwater were much smaller where no nonaqueous phase liquid was present, even if the groundwater was in contact with contaminated soils. This condition is attributed to weathering processes at the site, such as dissolution, volatilization, and biodegradation. Soluble, volatile, low-molecular-weight organic compounds are preferentially dissolved from the nonaqueous phase liquid into the groundwater. Where no nonaqueous phase liquid is present, only stained soils containing relatively insoluble, high-molecular-weight compounds remain; therefore, contaminant concentrations in the groundwater are much smaller. Concentrations of organic contaminants in the soils may still remain large. Values of specific conductance were as large as 5,280 microsiemens/cm, well above a background of 242 microsiemens/cm, suggesting large concentrations of minerals in the groundwater. Trace metal concentrations, however , were generally < 0.010 mg/L, and below limits of US EPA drinking water standards. Cyanide was present in groundwater samples from throughout the park, ranging in concentration from 0.01 to 8.6 mg/L. (Author 's abstract)

Geochemical processes and the effects of natural organic solutes on the solubility of selenium in coal-mine backfill samples from the Powder River basin, Wyoming

USGS Publications Warehouse

See, R.B.; Reddy, K.J.; Vance, G.F.; Fadlelmawla, A.A.; Blaylock, M.J.

1995-01-01

Geochemical processes and the effects of natural organic solutes on the solubility of selenium in coal-mine backfill aquifers were investigated. Backfill and ground-water samples were collected at coal mines in the Powder River Basin, Wyoming. Backfill was generally dominated by aluminum (14,400 to 49,000 mg/kg (milligrams per kilogram)), iron (3,330 to 23,200 mg/kg), and potassium (7,950 to 18,000 mg/kg). Backfill saturated-paste selenium concentrations ranged from 1 to 156 mg/kg (microsiemens per kilogram). Ground-water total selenium concentrations ranged from 3 to 125 mg/L. Dissolved organic carbon in all ground-water samples was dominated by hydrophobic and hydrophilic acids (38 to 84 percent). Selenite sorption/desorption experiments were conducted using background solutions of distilled-deionized water, 0.1 molar calcium chloride, and isolated hydrophobic and hydrophilic acids. Selenite sorption was larger when 0.1 molar calcium chloride was used. The addition of hydrophilic acid decreased selenite sorption more than the addition of hydrophobic acids. Geochemical modelling was used to predict the solid phases controlling dissolved selenium concentrations and to evaluate the effects of dissolved organic carbon on selenium solubility. Results suggested that 55 to 90 percent of selenium in backfill precipitation/dissolution extracts was dominated by magnesium selenate ion pairs. Dissolved organic carbon had little effect on selenium speciation. A redox chamber was constructed to control Eh and pH in water and backfill-core sample suspensions. The response of selenite and selenate in water samples to redox conditions did not follow thermodynamic predictions. Reduction of selenate in water samples did not occur at any of the redox levels tested.

A Conserving Discretization for the Free Boundary in a Two-Dimensional Stefan Problem

NASA Astrophysics Data System (ADS)

Segal, Guus; Vuik, Kees; Vermolen, Fred

1998-03-01

The dissolution of a disk-likeAl2Cuparticle is considered. A characteristic property is that initially the particle has a nonsmooth boundary. The mathematical model of this dissolution process contains a description of the particle interface, of which the position varies in time. Such a model is called a Stefan problem. It is impossible to obtain an analytical solution for a general two-dimensional Stefan problem, so we use the finite element method to solve this problem numerically. First, we apply a classical moving mesh method. Computations show that after some time steps the predicted particle interface becomes very unrealistic. Therefore, we derive a new method for the displacement of the free boundary based on the balance of atoms. This method leads to good results, also, for nonsmooth boundaries. Some numerical experiments are given for the dissolution of anAl2Cuparticle in anAl-Cualloy.

Understanding the barriers to crystal growth: dynamical simulation of the dissolution and growth of urea from aqueous solution.

PubMed

Piana, Stefano; Gale, Julian D

2005-02-16

Both the dissolution and growth of a molecular crystalline material, urea, has been studied using dynamical atomistic simulation. The kinetic steps of dissolution and growth are clearly identified, and the activation energies for each possible step are calculated. Our molecular dynamics simulations indicate that crystal growth on the [001] face is characterized by a nucleation and growth mechanism. Nucleation on the [001] urea crystal face is predicted to occur at a very high rate, followed by rapid propagation of the steps. The rate-limiting step for crystallization is actually found to be the removal of surface defects, rather than the initial formation of the next surface layer. Through kinetic Monte Carlo modeling of the surface growth, it is found that this crystal face evolves via a rough surface topography, rather than a clean layer-by-layer mechanism.

Effects of pretreatment processes for Zr electrorefining of oxidized Zircaloy-4 cladding tubes

NASA Astrophysics Data System (ADS)

Hwa Lee, Chang; Lee, Yoo Lee; Jeon, Min Ku; Choi, Yong Taek; Kang, Kweon Ho; Park, Geun Il

2014-06-01

The effect of pretreatment processes for the Zr electrorefining of oxidized Zircaloy-4 cladding tubes is examined in LiCl-KCl-ZrCl4 molten salts at 500 °C. The cyclic voltammetries reveal that the Zr dissolution kinetics is highly dependent on the thickness of a Zr oxide layer formed at 500 °C under air atmosphere. For the Zircaloy-4 tube covered with a 1 μm thick oxide layer, the Zr dissolution process is initiated from a non-stoichiometric Zr oxide surface through salt treatment at an open circuit potential in the molten salt electrolyte. The Zr dissolution of the samples in the middle range of oxide layer thickness appears to be more effectively derived by the salt treatment coupled with an anodic potential application at an oxidation potential of Zr. A modification of the process scheme offers an applicability of Zr electrorefining for the treatment of oxidized cladding hull wastes.

Controlled Dissolution of Phenytoin by Hybridizing with Silica Nanoparticles

NASA Astrophysics Data System (ADS)

Goto, H.; Isobe, T.; Senna, M.

1999-06-01

A sparingly soluble model drug, phenytoin (5,5-diphenyl-hydantoin, denoted as PT), was incorporated during or after hydrolysis and polycondensation of tetra orthoethyl silicate (TEOS) to obtain silica-drug hybrids. We also compare the hybrids obtained by sol-gel process with those obtained by simple adsorption on nonporous silica particles. The initial rate of dissolution in water increases by a factor of 40 with respect to the intact PT by aging silica before drug addition. The IR results show that νC=O in the position 2 of PT and νN-H shift toward the higher wavenumber, showing that intermolecular hydrogen bonds between C=O and N-H are loosened or broken to form new hydrogen bonds between C=O in PT and Si-OH in silica. The dissolution rate of PT is determined by the degree of the breakage of hydrogen bonds between PT molecules and the intensity of the interaction between silica and PT.

Romantic Partner Monitoring After Breakups: Attachment, Dependence, Distress, and Post-Dissolution Online Surveillance via Social Networking Sites.

PubMed

Fox, Jesse; Tokunaga, Robert S

2015-09-01

Romantic relationship dissolution can be stressful, and social networking sites make it difficult to separate from a romantic partner online as well as offline. An online survey (N = 431) tested a model synthesizing attachment, investment model variables, and post-dissolution emotional distress as predictors of interpersonal surveillance (i.e., "Facebook stalking") of one's ex-partner on Facebook after a breakup. Results indicated that anxious attachment predicted relational investment but also seeking relationship alternatives; avoidant attachment was negatively related to investment but positively related to seeking alternatives. Investment predicted commitment, whereas seeking alternatives was negatively related to commitment. Commitment predicted emotional distress after the breakup. Distress predicted partner monitoring immediately following the breakup, particularly for those who did not initiate the breakup, as well as current partner monitoring. Given their affordances, social media are discussed as potentially unhealthy enablers for online surveillance after relationship termination.

Gastric phytobezoars may be treated by nasogastric Coca-Cola lavage.

PubMed

Ladas, Spiros D; Triantafyllou, Konstantinos; Tzathas, Charalabos; Tassios, Pericles; Rokkas, Theodore; Raptis, Sotirios A

2002-07-01

Large gastric phytobezoars may occur in patients with gastric dysmotility disorders. Treatment options include dissolution with enzymes, endoscopic fragmentation with removal or aspiration, and surgery. We report our experience with nasogastric cola lavage therapy. Over an 8-year period, five consecutive patients were referred to our unit for endoscopic treatment of large gastric phytobezoars. They included one patient with lobectomy for lung cancer and four patients with diabetic gastroparesis. An initial attempt of endoscopic fragmentation and removal was unsuccessful. Patients were treated with 3 l of Coca-Cola nasogastric lavage over 12 h. Nasogastric lavage was very well tolerated by the patients. Complete phytobezoar dissolution was achieved in one session in all cases. There were no procedure-related complications. The dissolution of large gastric phytobezoars with cola nasogastric lavage is a safe, rapid and effective method. Patients may be treated in the medical ward, avoiding therapeutic endoscopy or surgery.

Solute transport by flow yields geometric shocks in shape evolution

NASA Astrophysics Data System (ADS)

Huang, Jinzi (Mac); Davies Wykes, Megan; Hajjar, George; Ristroph, Leif; Shelley, Michael

2017-11-01

Geological processes such as erosion and dissolution of surfaces often lead to striking shapes with strikingly sharp features. We present observations of such features forming in dissolution under gravity. In our experiment, a dissolving body with initially smooth surface evolves into an increasingly sharp needle shape. A mathematical model of its shape dynamics, derived from a boundary layer theory, predicts that a geometric shock forms at the tip of dissolved body, with the tip curvature becoming infinite in finite time. We further discuss the model's application to similar processes, such as flow driven erosion which can yield corners.

30 CFR 710.2 - Objectives.

Code of Federal Regulations, 2012 CFR

2012-07-01

... REGULATIONS INITIAL REGULATORY PROGRAM § 710.2 Objectives. The objectives of the initial regulatory program... resulting from surface coal mining operations during the interval between enactment of the Act and adoption of a permanent State or Federal regulatory program; and (b) Coordinate the State and Federal...

30 CFR 710.2 - Objectives.

Code of Federal Regulations, 2014 CFR

2014-07-01

... REGULATIONS INITIAL REGULATORY PROGRAM § 710.2 Objectives. The objectives of the initial regulatory program... resulting from surface coal mining operations during the interval between enactment of the Act and adoption of a permanent State or Federal regulatory program; and (b) Coordinate the State and Federal...

30 CFR 710.2 - Objectives.

Code of Federal Regulations, 2010 CFR

2010-07-01

... REGULATIONS INITIAL REGULATORY PROGRAM § 710.2 Objectives. The objectives of the initial regulatory program... resulting from surface coal mining operations during the interval between enactment of the Act and adoption of a permanent State or Federal regulatory program; and (b) Coordinate the State and Federal...

30 CFR 710.2 - Objectives.

Code of Federal Regulations, 2013 CFR

2013-07-01

... REGULATIONS INITIAL REGULATORY PROGRAM § 710.2 Objectives. The objectives of the initial regulatory program... resulting from surface coal mining operations during the interval between enactment of the Act and adoption of a permanent State or Federal regulatory program; and (b) Coordinate the State and Federal...

Chemicals from low temperature liquid-phase cracking of coals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sato, Y.; Kodera, Y.; Kamo, T.

1999-07-01

Mild gasification and low temperature pyrolysis are considered to be the most promising process for high-moisture subbituminous and lignite coal to produce upgraded solid fuel with high heating value and low sulfur, and to produce a useful liquid product. However effective technology to prevent spontaneous combustion of solid product and to utilize oxygen-rich liquid product has not yet been reported to enhance commercial feasibility of these process. In this study, liquid-phase cracking of low rank coal at 350--450 C under 2 MPa of initial nitrogen atmosphere has been studied to produce upgraded coal and value added liquid product. Liquid-phase crackingmore » of Wyoming subbituminous Buckskin coal using iron oxide catalyst in the presence of t-decalin at 440C gave 10 wt% of liquid product, 12 wt% of gases and 74 wt% of upgraded coal with small amount of water. Gaseous product consisted of mainly carbon dioxide (62wt%) and methane. Therefore, cracking of carboxylic function took place effectively in these conditions. Liquid product contains BTX, phenols and alkylphenols. Concentrated chemicals of BTX, phenol and cresols from the liquid products by hydrocracking and hydrotreating will be discussed.« less

In situ gasification process for producing product gas enriched in carbon monoxide and hydrogen

DOEpatents

Capp, John P.; Bissett, Larry A.

1978-01-01

The present invention is directed to an in situ coal gasification process wherein the combustion zone within the underground coal bed is fed with air at increasing pressure to increase pressure and temperature in the combustion zone for forcing product gases and water naturally present in the coal bed into the coal bed surrounding the combustion zone. No outflow of combustion products occurs during the build-up of pressure and temperature in the combustion zone. After the coal bed reaches a temperature of about 2000.degree. F and a pressure in the range of about 100-200 psi above pore pressure the airflow is terminated and the outflow of the combustion products from the combustion zone is initiated. The CO.sub.2 containing gaseous products and the water bleed back into the combustion zone to react endothermically with the hot carbon of the combustion zone to produce a burnable gas with a relatively high hydrogen and carbon monoxide content. About 11 to 29 percent of the gas recovered from the combustion zone is carbon monoxide which is considerably better than the 4 to 10 percent carbon monoxide obtained by employing previously known coal gasification techniques.

Feedbacks of Density and Viscosity Nonlinearities on Convective Mixing: Experiments and High-resolution Simulations

NASA Astrophysics Data System (ADS)

Hidalgo, J. J.; MacMinn, C. W.; Cueto-Felgueroso, L.; Fe, J.

2011-12-01

Dissolution by convective mixing is one of the main trapping mechanisms during CO2 sequestration in saline aquifers. The free-phase CO2 tends to rise due to buoyancy, accumulate beneath the caprock and dissolve into the brine, initially by diffusion. The CO2-brine mixture, however, is denser than the two initial fluids, leading to a Rayleigh-Bénard-type instability known as convective mixing, which greatly accelerates CO2 dissolution. Although this is a well-known process, it remains unclear how convective mixing scales with the governing parameters of the system and its impact on the actual mixing of CO2 and brine. Here, we perform high-resolution numerical simulations and laboratory experiments with an analogue fluid system (water and propylene glycol) to explore the dependence of the CO2 dissolution flux on the nonlinearity of the density and viscosity of the fluid mixture. We find that the convective flux depends strongly on the value of the concentration for which the density of the mixture is maximum, and on the viscosity contrast between the fluids. From the experimental and simulation results we elucidate the scaling behavior of convective mixing, and clarify the role of nonlinear density and viscosity feedbacks in the interpretation of the analogue-fluid experiments.

Experiments and High-resolution Simulations of Density and Viscosity Feedbacks on Convective Mixing

NASA Astrophysics Data System (ADS)

Hidalgo, Juan J.; Fe, Jaime; MacMinn, Christopher W.; Cueto-Felgueroso, Luis; Juanes, Ruben

2011-11-01

Dissolution by convective mixing is one of the main trapping mechanisms during CO2 sequestration in saline aquifers. Initially, the buoyant CO2 dissolves into the underlying brine by diffusion. The CO2-brine mixture is denser than the two initial fluids, leading to a Rayleigh-Bénard-type instability known as convective mixing, which greatly accelerates CO2 dissolution. Although this is a well-known process, it remains unclear how convective mixing scales with the governing parameters of the system and its impact on the actual mixing of CO2 and brine. We explore the dependence of the CO2 dissolution flux on the nonlinearity of the density and viscosity of the fluid mixture by means of high-resolution numerical simulations and laboratory experiments with an analogue fluid system (water and propylene glycol). We find that the value of the concentration for which the density of the mixture is maximum, and the viscosity contrast between the fluids, both exert a powerful control on the convective flux. From the experimental and simulation results, we obtain the scaling behavior of convective mixing, and clarify the role of nonlinear density and viscosity feedbacks. JJH acknowledges the support from the FP7 Marie Curie Actions of the European Commission, via the CO2-MATE project (PIOF-GA-2009-253678).

Salt dissolution sinkhole at the Weeks Island, Louisiana, Strategic Petroleum Reserve storage site

DOE Office of Scientific and Technical Information (OSTI.GOV)

Neal, J.T.; Myers, R.E.

1994-12-31

A sinkhole was first observed in May 1992 over the outer edge of the two-tiered former salt mine that was converted for oil storage by the US Strategic Petroleum Reserve (SPR). Results of diagnostic studies which included geophysical, geochemical, drilling, and hydrological methods suggest a direct connection exists between the surface collapse area and the underground mine. The connection was confirmed by correlative measurements of sediment slump rates, piezometric surface deflection, and brine influx rates into the mine. The dissolution of salt below the sinkhole that initiated the leak into the mine was likely caused by several confluent geologic processes,more » and exacerbated by mining-induced stresses that created fractures which severed as hydrologic flowpaths. Modeling studies of mine stresses show that years of tensional stresses may be required before cracking begins to occur, but once begun can continue to develop, and relieve the stress in that specific regime. The crack regime creates the avenue for incursion of groundwater, very slowly initially, but gradually enlarging as undersaturated groundwater dissolves salt on the sides of the crack. Mitigative measures include increasing the mine pressurization, slowing the dissolution by injecting brine into the sinkhole throat, and permeation grouting in hydrologic flowpaths.« less

Installation of a stoker-coal preparation plant in Krakow, Poland. Quarterly technical progress report No. 1, May--July, 1994

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rozelle, P.

1996-01-01

This report describes the progress made during the first Quarter of a two year project to demonstrate that the air pollution from a traveling grate stoker being used to heat water at a central heating plant in Krakow Poland can be reduced significantly by replacing the unwashed, unsized coal now being used with a mechanically cleaned, double sized stoker fuel and by optimizing the operating parameters of the stoker. It is anticipated that these improvements will prove to be cost effective and hence be adopted in the other central heating plants in Krakow and indeed throughout Eastern European cities wheremore » coal is the primary source of heating fuel. EFH Coal Company has formed a partnership with two Polish institutions -- MPEC a central heating company in Krakow and Naftokrak-Naftobudowa, preparation plant designers and fabricators, for this effort. An evaluation of the washability characteristics of five samples of two coals (Piast and Janina) showed that {open_quotes}compliance-quality{close_quotes} stoker coals could be produced which contained less than 640 g of SO{sub 2}/KJ (1.5 lbs SO{sub 2}/MMBtu) at acceptable plant yields by washing in heavy media cyclones. A search for long-term sources of raw coal to feed the proposed new 300 tph stoker coal preparation plant was initiated. As the quantity of stoker coal that will be produced (300 tph) at the new plant will exceed the demand by MPEC, a search for other and additional potential markets was begun. Because the final cost of the stoker coal will be influenced by such factors as the plant`s proximity to both the raw coal supply and the customers, the availability and cost of utilities, and the availability of suitable refuse disposal areas, these concerns were the topic of discussions at the many meetings that were held between EFH Coal and the Polish Partners.« less

A Combined Micro-CT Imaging/Microfluidic Approach for Understating Methane Recovery in Coal Seam Gas Reservoirs

NASA Astrophysics Data System (ADS)

Mostaghimi, P.; Armstrong, R. T.; Gerami, A.; Lamei Ramandi, H.; Ebrahimi Warkiani, M.

2015-12-01

Coal seam methane is a form of natural gas stored in coal beds and is one of the most important unconventional resources of energy. The flow and transport in coal beds occur in a well-developed system of natural fractures that are also known as cleats. We use micro-Computed Tomography (CT) imaging at both dry and wet conditions to resolve the cleats below the resolution of the image. Scanning Electron Microscopy (SEM) is used for calibration of micro-CT data. Using soft lithography technique, the cleat system is duplicated on a silicon mould. We fabricate a microfluidic chip using Polydimethylsiloxane (PDMS) to study both imbibition and drainage in generated coal structures for understating gas and water transport in coal seam reservoirs. First, we use simple patterns observed on coal images to analyse the effects of wettability, cleat size and distribution on flow behaviour. Then, we study transport in a coal by injecting both distilled water and decane with a rate of 1 microliter/ min into the fabricated cleat structure (Figure 1), initially saturated with air. We repeat the experiment for different contact angles by plasma treating the microfluidic chip, and results show significant effects of wettability on the displacement efficiency. The breakthrough time in the imbibition setup is significantly longer than in the drainage. Using rapid video capturing, and high resolution microscopy, we measure the saturation of displacing fluid with respect to time. By measuring gas and liquid recovery in the outlet at different saturation, we predict relative permeability of coal. This work has important applications for optimising gas recovery and our results can serve as a benchmark in the verification of multiphase numerical models used in coal seam gas industry.

Testing of advanced liquefaction concepts in HTI Run ALC-1: Coal cleaning and recycle solvent treatment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Robbins, G.A.; Winschel, R.A.; Burke, F.P.

In 1991, the Department of Energy initiated the Advanced Liquefaction Concepts Program to promote the development of new and emerging technology that has potential to reduce the cost of producing liquid fuels by direct coal liquefaction. Laboratory research performed by researchers at CAER, CONSOL, Sandia, and LDP Associates in Phase I is being developed further and tested at the bench scale at HTI. HTI Run ALC-1, conducted in the spring of 1996, was the first of four planned tests. In Run ALC-1, feed coal ash reduction (coal cleaning) by oil agglomeration, and recycle solvent quality improvement through dewaxing and hydrotreatmentmore » of the recycle distillate were evaluated. HTI`s bench liquefaction Run ALC-1 consisted of 25 days of operation. Major accomplishments were: 1) oil agglomeration reduced the ash content of Black Thunder Mine coal by 40%, from 5.5% to 3.3%; 2) excellent coal conversion of 98% was obtained with oil agglomerated coal, about 3% higher than the raw Black Thunder Mine coal, increasing the potential product yield by 2-3% on an MAF coal basis; 3) agglomerates were liquefied with no handling problems; 4) fresh catalyst make-up rate was decreased by 30%, with no apparent detrimental operating characteristics, both when agglomerates were fed and when raw coal was fed (with solvent dewaxing and hydrotreating); 5) recycle solvent treatment by dewaxing and hydrotreating was demonstrated, but steady-state operation was not achieved; and 6) there was some success in achieving extinction recycle of the heaviest liquid products. Performance data have not been finalized; they will be available for full evaluation in the new future.« less

Preparation and characterization of poly(lactic acid) nanoparticles for sustained release of pyridostigmine bromide.

PubMed

Tan, Q Y; Xu, M L; Wu, J Y; Yin, H F; Zhang, J Q

2012-04-01

A novel pyridostigmine bromide poly (lactic acid) nanoparticles (PBPNPs) was prepared to obtain sustained release characteristics of PB. A central composite design approach was employed for process optimization. The in vitro release studies were carried out by dialysis method and conducted using four different dissolution media. Similar factor method was investigated for dissolution profile comparison. Multiple linear regression analysis for process optimization revealed that the optimal PBPNPs were obtained where the values of the amount of PB (X1, mg), PLA concentration (X2, % w:v), and PVA concentration (X3, % w:v) were 49.20 mg, 3.31% and 3.41%, respectively. The average particle size and zeta potential of PBPNPs with the optimized formulation were 722.9 +/- 4.3 nm, and -25.12 +/- 1.2 mV, respectively. PBPNPs provided an initial burst of drug release followed by a very slow release over an extended period of time (72 h). Compared with free PB, PBPNPs had a significantly lower release rate of PB in vitro. The in vitro release profile of the PBPNPs could be described by Weibull models, regardless of type of dissolution medium. Statistical significance of similarity between every two dissolution profiles of PBPNPs in different dissolution media was found, and the difference between the curves of PBPNPs and pure PB was statistically significant.

Self-sculpting of a dissolvable body due to gravitational convection

NASA Astrophysics Data System (ADS)

Davies Wykes, Megan S.; Huang, Jinzi Mac; Hajjar, George A.; Ristroph, Leif

2018-04-01

Natural sculpting processes such as erosion or dissolution often yield universal shapes that bear no imprint or memory of the initial conditions. Here we conduct laboratory experiments aimed at assessing the shape dynamics and role of memory for the simple case of a dissolvable boundary immersed in a fluid. Though no external flow is imposed, dissolution and consequent density differences lead to gravitational convective flows that in turn strongly affect local dissolving rates and shape changes, and we identify two distinct behaviors. A flat boundary dissolving from its lower surface tends to retain its overall shape (an example of near perfect memory) while bearing small-scale pits that reflect complex near-body flows. A boundary dissolving from its upper surface tends to erase its initial shape and form an upward spike structure that sharpens indefinitely. We propose an explanation for these different outcomes based on observations of the coupled shape dynamics, concentration fields, and flows.

Marital Dissolution and Major Depression in Midlife: A Propensity Score Analysis.

PubMed

Sbarra, David A; Emery, Robert E; Beam, Christopher R; Ocker, Bailey L

2014-05-01

Marital dissolution is commonly assumed to cause increased depression among adults, but causality can be questioned based on directionality and third variable concerns. The present study improves upon past research by using a propensity score matching algorithm to identify a sub-sample of continuously married participants equivalent in divorce risk to participants who actually experienced separation/divorce between two waves of the nationally representative study, Midlife Development in the United States (MIDUS). After correcting for participants' propensity to separate/divorce, increased rates of depression at the second assessment were observed only among participants who were (a) depressed at the initial assessment, and (b) experienced a separation/divorce. Participants who were not depressed at the initial assessment but who experienced a separation/divorce were not at increased risk for a later major depressive disorder (MDE). Thus, both social selection and social causation contribute to the increased risk for a MDE found among separated/divorced adults.

Study on HOPE Management Mode of Coal Enterprises Based on Systematic Thinking

NASA Astrophysics Data System (ADS)

Zhaoran, Zhang; Tianzhu, Zhang; Wenjing, Tong

2018-02-01

The extensive management mode of coal enterprises is no longer applicable to the demand of enterprise development under the new economic situation. Combined with the characteristics of coal mine production, based on the system of thinking, integration of lean, people, comprehensive, job management theory, formed HOPE management model, including a core system and three support systems and 18 elements. There are three stages in the development and implementation of this model. To 6S site management for the initial stage to job process reengineering for the intermediate stage to post value process control for the advanced stage. The successful implementation of HOPE model in coal enterprises needs comprehensive control from five aspects: lean culture construction, flattening organizational structure, cost control system, performance appraisal system and lean information management platform. HOPE model can be implemented smoothly and make “win-win” between enterprises and employees.

Reconnaissance for uranium in the coal of Sao Paulo, Santa Catarina, and Rio Grande do Sul, Brazil

USGS Publications Warehouse

Haynes, Donald D.; Pierson, Charles T.; White, Max G.

1958-01-01

Uranium-bearing coal and carbonaceous shale of the Rio Bonito formation of Pennsylvanian age have been found in the States of Sao Paulo, Santa Catarlna and Rio Grande do Sul, Brazil. The uranium oxide content of the samples collected in the State of Sao Paulo ranges from 0.001 percent to 0.082 percent. The samples collected in Santa Catarina averaged about 0.002 percent uranium oxide; those collected in Rio Grande do Sul, about 0.003 percent uranium oxide. Since the field and laboratory investigations are still in their initial stages, only raw data on the radioactivity and uranium content of Brazilian coals are given in this report.

The role of fluids in rock layering development: a pressure solution self-organized process revealed by laboratory experiments

NASA Astrophysics Data System (ADS)

Gratier, Jean-Pierre; Noiriel, Catherine; Renard, Francois

2015-04-01

Natural deformation of rocks is often associated with stress-driven differentiation processes leading to irreversible transformations of their microstructures. The development mechanisms of such processes during diagenesis, tectonic, metamorphism or fault differentiation are poorly known as they are difficult to reproduce experimentally due to the very slow kinetics of stress-driven chemical processes. Here, we show that experimental compaction with development of differentiated layering, similar to what happens in natural deformation, can be obtained by indenter techniques in laboratory conditions. Samples of plaster mixed with clay and of diatomite loosely interbedded with volcanic dust were loaded in presence of their saturated aqueous solutions during several months at 40°C and 150°C, respectively. High-resolution X-ray microtomography and scanning electron microscopy observations show that the layering development is a pressure solution self-organized process. Stress-driven dissolution of the soluble minerals (either gypsum or silica) is initiated in the areas initially richer in insoluble minerals (clays or volcanic dust) because the kinetics of diffusive mass transfer along the soluble/insoluble mineral interfaces is much faster than along the healed boundaries of the soluble minerals. The passive concentration of insoluble minerals amplifies the localization of dissolution along some layers oriented perpendicular to the maximum compressive stress. Conversely, in the areas with initial low content in insoluble minerals and clustered soluble minerals, dissolution is slower. Consequently, these areas are less deformed, they host the re-deposition of the soluble species and they act as rigid objects that concentrate the dissolution near their boundaries thus amplifying the differentiation. A crucial parameter required for self-organized process of pressure solution is the presence of a fluid that is a good solvent of at least some of the rock-forming minerals. Another general requirement for the development of such differentiated layering is the heterogeneous mixing of variously soluble and insoluble species. From a general point of view, the development of diagenetic or tectonic layering has crucial consequences in geological processes. The main one is to modify the composition and microstructure of rocks by dissolution of the most soluble species, passive concentration of the insoluble species and re-deposition of the dissolved species at a distance that depends on the transport efficiency (diffusion or advection). Consequently, layering development modifies both the rheological and the transfer properties of rocks. It is the most common strain localization process in the upper crust when a reactive fluid phase is present, complementary to other strain localization processes in the lithosphere. A specific effect is the development of anisotropic properties that may favor local sliding on weak surfaces. This is particularly important in fault zones where pressure solution processes are at work. Modeling of differentiated layering during natural deformation must be rooted in the stress-driven dissolution and transport properties of the various minerals forming the rocks, and on the evolution of their rheological properties. The strength evolution can be taken into account through a weakening factor in the zone of dissolution and a strengthening factor in the zone of deposition. The kinetics evolution is controlled by the critical parameters of pressure solution.

Flow microcapillary plasma mass spectrometry-based investigation of new Al-Cr-Fe complex metallic alloy passivation.

PubMed

Ott, N; Beni, A; Ulrich, A; Ludwig, C; Schmutz, P

2014-03-01

Al-Cr-Fe complex metallic alloys are new intermetallic phases with low surface energy, low friction, and high corrosion resistance down to very low pH values (0-2). Flow microcapillary plasma mass spectrometry under potentiostatic control was used to characterize the dynamic aspect of passivation of an Al-Cr-Fe gamma phase in acidic electrolytes, allowing a better insight on the parameters inducing chemical stability at the oxyhydroxide-solution interface. In sulfuric acid pH 0, low element dissolution rates (in the µg cm(-2) range after 60 min) evidenced the passive state of the Al-Cr-Fe gamma phase with a preferential over-stoichiometric dissolution of Al and Fe cations. Longer air-aging was found to be beneficial for stabilizing the passive film. In chloride-containing electrolytes, ten times higher Al dissolution rates were detected at open-circuit potential (OCP), indicating that the spontaneously formed passive film becomes unstable. However, electrochemical polarization at low passive potentials induces electrical field generated oxide film modification, increasing chemical stability at the oxyhydroxide-solution interface. In the high potential passive region, localized attack is initiated with subsequent active metal dissolution. © 2013 Published by Elsevier B.V.

Formulation and evaluation of diclofenac controlled release matrix tablets made of HPMC and Poloxamer 188 polymer: An assessment on mechanism of drug release.

PubMed

Al-Hanbali, Othman A; Hamed, Rania; Arafat, Mosab; Bakkour, Youssef; Al-Matubsi, Hisham; Mansour, Randa; Al-Bataineh, Yazan; Aldhoun, Mohammad; Sarfraz, Muhammad; Dardas, Abdel Khaleq Yousef

2018-01-01

In this study, hydrophilic hydroxypropyl methylcellulose matrices with various concentrations of Poloxamer 188 were used in the development of oral controlled release tablets containing diclofenac sodium. Four formulations of hydrophilic matrix tablets containing 16.7% w/w HPMC and 0, 6.7, 16.7 and 25.0% w/w Poloxamer 188, respectively, were developed. Tablets were prepared by direct compression and characterized for diameter, hardness, thickness, weight and uniformity of content. The influence of various blends of hydroxypropyl methylcellulose and Poloxamer 188 on the in vitro dissolution profile and mechanism of drug release of was investigated. In the four formulations, the rate of drug release decreased with increasing the concentration of Poloxamer 188 at the initial dissolution stages due to the increase in the apparent viscosity of the gel diffusion layer. However, in the late dissolution stages, the rate of drug release increased with increasing Poloxamer 188 concentration due to the increase in wettability and dissolution of the matrix. The kinetic of drug release from the tablets followed non-Fickian mechanism, as predicted by Korsmeyer-Peppas model, which involves diffusion through the gel layer and erosion of the matrix system.

Supersaturation and crystallization: non-equilibrium dynamics of amorphous solid dispersions for oral drug delivery.

PubMed

Kawakami, Kohsaku

2017-06-01

Amorphous solid dispersions (ASDs) are one of the key formulation technologies that aid the development of poorly soluble candidates. However, their dynamic behaviors, including dissolution and crystallization processes, are still full of mystery. Further understanding of these processes should enhance their wider use. Areas covered: The first part of this review describes the current understanding of the dissolution of ASDs, where phase separation behavior is frequently involved and attempts to develop appropriate dissolution tests to achieve an in vitro-in vivo correlation are examined. The second part of this review discusses crystallization of the drug molecule with the eventual aim of establishing an accelerated testing protocol for predicting its physical stability. Expert opinion: The phase separation behavior from the supersaturated state during the dissolution test must be understood, and its relevance to the oral absorption behavior needs to be clarified. Research efforts should focus on the differences between the phase behavior in in vitro and in vivo situations. Initiation time of the crystallization was shown to be predicted only from storage and glass transition temperatures. This finding should encourage the establishment of testing protocol of the physical stability of ASDs.

A conversion of CO2-ECBM related lab observations to reservoir requirements

NASA Astrophysics Data System (ADS)

Gensterblum, Yves; Merkel, Alexej; Busch, Andreas; Krooß, Bernhard

2013-04-01

To predict a CBM production profile either during primary or secondary production, aspects like coal permeability and porosity, density, ash and moisture content, initial gas-in-place (GIP) (from canister desorption tests), gas sorption capacity from laboratory isotherms (to obtain gas saturations and desorption pressure), gas diffusivities, coal volumetrics (thickness and areal extent) need to be understood as a minimum requirement. When dealing with CO2-ECBM selective adsorption, counter diffusion in the coal matrix, or coal shrinkage and swelling (from CH4 desorption and CO2 adsorption, respectively) and the influence of moisture need to be investigated in addition to the parameters above. During CO2-ECBM processes, the areal distribution of the CO2 injected is accomplished by flow through the cleat network. When CO2 is entering the coal matrix by a combined sorption/diffusion process it will adsorb to the coal inner surface and at the same time replace part of the CH4. This replacement occurs either by a reduction in the CH4 partial pressure or by a higher selective sorption of CO2 over CH4. Because of a concentration gradient between CH4 in the matrix compared to the cleat system, CH4 diffuses from the coal matrix into the cleat system where, by pressure drawdown towards a production well, it can be produced. In this context this presentation summarizes gas (CO2, CH4) and water sorption on coal and specifically addresses the following topics: • CH4 and CO2 sorption capacity as a function depth and rank • CO2 and CH4 sorption on natural coals and its dependence on coal specific parameters like coal rank, maceral composition or ash content (Busch and Gensterblum, 2011). • Water sorption on coal, its dependence on coal properties such as rank and coal chemistry and gas sorption in the presence of water (Busch and Gensterblum, 2011). • Uncertainties in reservoir characterisation (Gensterblum et al., 2010; Gensterblum et al., 2009) • Sorption uptake kinetic as a function of surface coverage and the influence of moisture on the kinetic Busch, A. and Gensterblum, Y., 2011. CBM and CO2-ECBM related sorption processes in coal: A review. International Journal of Coal Geology, 87: 49-71. Gensterblum, Y. et al., 2010. European inter-laboratory comparison of high pressure CO2 sorption isotherms II: Natural coals. International Journal of Coal Geology, 84(2): 115-124. Gensterblum, Y. et al., 2009. European inter-laboratory comparison of high pressure CO2 sorption isotherms. I: Activated carbon. Carbon, 47(13): 2958-2969.

Homer City Multistream Coal Cleaning Demonstration: A progress report. Report for January 1979-July 1983

DOE Office of Scientific and Technical Information (OSTI.GOV)

Carey, D.W.; Higgins, S.T.; Slowik, A.A.

1984-08-01

The report gives an overview of ongoing testing and evaluation of the Homer City Coal Cleaning Plant, built to enable the Homer City Power Complex to meet sulfur dioxide (SO2) emission levels mandated by the State of Pennsylvania and the U.S. Government. The plant was constructed as a result of an extensive comparative evaluation of flue gas desulfurization (FGD) and physical coal cleaning. The Homer City System, the Multistream Coal Cleaning System (MCCS), was chosen as an economical alternative to FGD. The plant contains circuits for cleaning coarse, medium, and fine coals and for recovering fine and very fine coals.more » The dominant type of cleaning equipment used in the plant is the dense medium cyclone. The original '93 plant' configuration was never able to clean coal to the conditions specified in the plant design. An extensive test and evaluation program was begun to identify and correct the causes of plant operating problems. After extensive pilot plant equipment tests and engineering studies were completed, recommendations were made for plant modifications necessary to correct the design and operating deficiencies of the plant. Extensive modifications were made to one of two parallel processing trains in the plant (the 'B' circuits), and a test program was initiated to evaluate these corrective measures. The modified 'B' circuits have not yet met design conditions.« less

Saga of coal bed methane, Ignacio Blanco gas field, Colorado

DOE Office of Scientific and Technical Information (OSTI.GOV)

Boyce, B.C.; Harr, C.L.; Burch, L.C.

1989-09-01

Prior to the 1977 discovery of the Cedar Hill Basal Fruitland pool (the first officially designated coal-bed methane field in the western US) 28.5 bcf of gas had been produced from Fruitland Formation coal seams in the Ignacio Blanco Fruitland-Pictured Cliffs field, Northern San Juan basin, Colorado. The discovery well for the field, Southern Ute D-1, was drilled and completed in 1951 on the Ignacio anticline, La Plata County, Colorado. Initial completion was attempted in the Pictured Cliffs Sandstone. The well was plugged back after making water from the Pictured Cliffs and was completed in the lower coal-bearing section ofmore » the Fruitland Formation. The well produced 487,333 mcf of gas in nine years and was abandoned in 1959 due to water encroachment. Additionally, 52 similarly completed Ignacio anticline Fruitland wells were abandoned by the early 1970s due to the nemesis of If it's starting to kick water, you're through. Under today's coal-bed methane technology and economics, Amoco has twinned 12 of the abandoned wells, drilled five additional wells, and is successfully dewatering and producing adsorbed methane from previously depleted coal sections of the Ignacio structure. Field-wide drilling activity in 1988 exceeded all previous annual levels, with coal-seam degasification projects leading the resurgence. Drilling and completion forecasts for 1989 surpass 1988 levels by 50%.« less

Effects of igneous intrusion on microporosity and gas adsorption capacity of coals in the Haizi Mine, China.

PubMed

Jiang, Jingyu; Cheng, Yuanping

2014-01-01

This paper describes the effects of igneous intrusions on pore structure and adsorption capacity of the Permian coals in the Huaibei Coalfield, China. Twelve coal samples were obtained at different distances from a ~120 m extremely thick sill. Comparisons were made between unaltered and heat-affected coals using geochemical data, pore-fracture characteristics, and adsorption properties. Thermal alteration occurs down to ~1.3 × sill thickness. Approaching the sill, the vitrinite reflectance (R(o)) increased from 2.30% to 2.78%, forming devolatilization vacuoles and a fine mosaic texture. Volatile matter (VM) decreased from 17.6% to 10.0% and the moisture decreased from 3.0% to 1.6%. With decreasing distance to the sill, the micropore volumes initially increased from 0.0054 cm(3)/g to a maximum of 0.0146 cm(3)/g and then decreased to 0.0079 cm(3)/g. The results show that the thermal evolution of the sill obviously changed the coal geochemistry and increased the micropore volume and adsorption capacity of heat-affected coal (60-160 m from the sill) compared with the unaltered coals. The trap effect of the sill prevented the high-pressure gas from being released, forming gas pocket. Mining activities near the sill created a low pressure zone leading to the rapid accumulation of methane and gas outbursts in the Haizi Mine.

Energy technologies and the environment: Environmental information handbook

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1988-10-01

This revision of Energy Technologies and the Environment reflects the changes in energy supply and demand, focus of environmental concern, and emphasis of energy research and development that have occurred since publication of the earlier edition in 1980. The increase in availability of oil and natural gas, at least for the near term, is responsible in part for a reduced emphasis on development of replacement fuels and technologies. Trends in energy development also have been influenced by an increased reliance on private industry initiatives, and a correspondingly reduced government involvement, in demonstrating more developed technologies. Environmental concerns related to acidmore » rain and waste management continue to increase the demand for development of innovative energy systems. The basic criteria for including a technology in this report are that (1) the technology is a major current or potential future energy supply and (2) significant changes in employing or understanding the technology have occurred since publication of the 1980 edition. Coal is seen to be a continuing major source of energy supply, and thus chapters pertaining to the principal coal technologies have been revised from the 1980 edition (those on coal mining and preparation, conventional coal-fired power plants, fluidized-bed combustion, coal gasification, and coal liquefaction) or added as necessary to include emerging technologies (those on oil shale, combined-cycle power plants, coal-liquid mixtures, and fuel cells).« less

Coprocessing of plastics with coal and petroleum resid

DOE Office of Scientific and Technical Information (OSTI.GOV)

Joo, H.; Curtis, C.W.

1995-12-31

Waste plastics have become an increasing problem in the United States since land filling is no longer considered a feasible disposal method. Since plastics are petroleum-derived materials, coprocessing then with coal to produce transportation fuels is a feasible alternative. In this study, catalytic coprocessing reactions were performed using Blind Canyon bituminous coal, Manji petroleum resid, and waste plastics. Model polymers including polystyrene, low density polyethylene (LDPE) and polyethylene tereplithalare (PET) were selected because they represent a substantial portion of the waste plastics generated in the United States. Coprocessing reactions of coal, resid, and polymer as well as reactions of individualmore » components and combinations of two components were performed at 430{degrees}C for one hour with an initial H{sub 2} pressure of 8.5 MPa introduced at ambient temperature with presulfided NiMo/Al{sub 2}O{sub 3} as catalyst. Coprocessing all three materials resulted in a substantial improvement in the total conversion compared to the coal plus polymer reaction and slightly less conversion than the resid plus polymer combinations.« less

Modeling and experiments for the time-dependent diffusion coefficient during methane desorption from coal

NASA Astrophysics Data System (ADS)

Cheng-Wu, Li; Hong-Lai, Xue; Cheng, Guan; Wen-biao, Liu

2018-04-01

Statistical analysis shows that in the coal matrix, the diffusion coefficient for methane is time-varying, and its integral satisfies the formula μt κ /(1 + β κ ). Therefore, a so-called dynamic diffusion coefficient model (DDC model) is developed. To verify the suitability and accuracy of the DDC model, a series of gas diffusion experiments were conducted using coal particles of different sizes. The results show that the experimental data can be accurately described by the DDC and bidisperse models, but the fit to the DDC model is slightly better. For all coal samples, as time increases, the effective diffusion coefficient first shows a sudden drop, followed by a gradual decrease before stabilizing at longer times. The effective diffusion coefficient has a negative relationship with the size of the coal particle. Finally, the relationship between the constants of the DDC model and the effective diffusion coefficient is discussed. The constant α (μ/R 2 ) denotes the effective coefficient at the initial time, and the constants κ and β control the attenuation characteristic of the effective diffusion coefficient.

Developing methanogenic microbial consortia from diverse coal sources and environments

DOE PAGES

Fuertez, John; Boakye, Richard; McLennan, John; ...

2017-08-18

Biogenic gas production is a promising alternative or supplement to conventional methane extraction from coalbeds. Adsorbed and free gas, generated over geologic time, can be supplemented with biogenic gas during short-term engineering operations. There are two generic protocols for doing this. The first is to contact the coal with nutrients to support native bacterial development. The second approach is to inject appropriately cultured ex-situ consortia into subsurface coal accumulations. Research has mainly focused on the former: in-situ stimulation of native microbial communities with added nutrients. Relatively few studies have been conducted on the strategies for enriching ex-situ microbial populations undermore » initial atmospheric exposure for subsequent injection into coal seams to stimulate biodegradation, and methanogenesis. In order to evaluate the feasibility of ex-situ cultivation, natural microbial populations were collected from various hydrocarbon-rich environments and locations characterized by natural methanogenesis. Different rank coals (i.e., lignite, sub-bituminous, bituminous), complex hydrocarbon sources (i.e., oil shale, waxy crude), hydrocarbon seeps, and natural biogenic environments were incorporated in the sampling. Three levels of screening (down-selection to high grade the most productive consortia) allowed selection of microbial populations, favorable nutrient amendments, sources of the microbial community, and quantification of methane produced from various coal types. Incubation periods of up to twenty-four weeks were evaluated at 23 °C. Headspace concentrations of CH 4 and CO 2 were analyzed by gas chromatography. After a two-week incubation period of the most promising microbes, generated headspace gas concentrations reached 873,400 ppm (154 sft 3/ton or 4.8 scm 3/g) for methane and 176,370 ppm (31 sft 3/ton or 0.9 scm 3/g) for carbon dioxide. Rudimentary statistical assessments – variance analysis (ANOVA) of a single factor - were used to identify trends and levels of significance or impact of the consortia enrichment. We then demonstrated that microbial communities from coal and lake sediments can be enriched and adapted to effectively generate methane under initial atmospheric exposure. The development and enrichment of these methanogenic consortia is described.« less

Developing methanogenic microbial consortia from diverse coal sources and environments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fuertez, John; Boakye, Richard; McLennan, John

Biogenic gas production is a promising alternative or supplement to conventional methane extraction from coalbeds. Adsorbed and free gas, generated over geologic time, can be supplemented with biogenic gas during short-term engineering operations. There are two generic protocols for doing this. The first is to contact the coal with nutrients to support native bacterial development. The second approach is to inject appropriately cultured ex-situ consortia into subsurface coal accumulations. Research has mainly focused on the former: in-situ stimulation of native microbial communities with added nutrients. Relatively few studies have been conducted on the strategies for enriching ex-situ microbial populations undermore » initial atmospheric exposure for subsequent injection into coal seams to stimulate biodegradation, and methanogenesis. In order to evaluate the feasibility of ex-situ cultivation, natural microbial populations were collected from various hydrocarbon-rich environments and locations characterized by natural methanogenesis. Different rank coals (i.e., lignite, sub-bituminous, bituminous), complex hydrocarbon sources (i.e., oil shale, waxy crude), hydrocarbon seeps, and natural biogenic environments were incorporated in the sampling. Three levels of screening (down-selection to high grade the most productive consortia) allowed selection of microbial populations, favorable nutrient amendments, sources of the microbial community, and quantification of methane produced from various coal types. Incubation periods of up to twenty-four weeks were evaluated at 23 °C. Headspace concentrations of CH 4 and CO 2 were analyzed by gas chromatography. After a two-week incubation period of the most promising microbes, generated headspace gas concentrations reached 873,400 ppm (154 sft 3/ton or 4.8 scm 3/g) for methane and 176,370 ppm (31 sft 3/ton or 0.9 scm 3/g) for carbon dioxide. Rudimentary statistical assessments – variance analysis (ANOVA) of a single factor - were used to identify trends and levels of significance or impact of the consortia enrichment. We then demonstrated that microbial communities from coal and lake sediments can be enriched and adapted to effectively generate methane under initial atmospheric exposure. The development and enrichment of these methanogenic consortia is described.« less

REGULATION OF COAL POLYMER DEGRADATION BY FUNGI

DOE Office of Scientific and Technical Information (OSTI.GOV)

John A. Bumpus

1998-11-30

A variety of lignin degrading fungi mediate solubilization and subsequent biodegradation of coal macromolecules (a.k.a. coal polymer) from highly oxidized low rank coals such as leonardites. It appears that oxalate or possibly other metal chelators (i.e., certain Krebs Cycle intermediates) mediate solubilization of low rank coals while extracellular oxidases have a role in subsequent oxidation of solubilized coal macromolecule. These processes are under nutritional control. For example, in the case of P. chrysosporium, solubilization of leonardite occurred when the fungi were cultured on most but not all nutrient agars tested and subsequent biodegradation occurred only in nutrient nitrogen limited cultures.more » Lignin peroxidases mediate oxidation of coal macromolecule in a reaction that is dependent on the presence of veratryl alcohol and hydrogen peroxide. Kinetic evidence suggests that veratryl alcohol is oxidized to the veratryl alcohol cation radical which then mediates oxidation of the coal macromolecule. Results by others suggest that Mn peroxidases mediate formation of reactive Mn{sup 3+} complexes which also mediate oxidation of coal macromolecule. A biomimetic approach was used to study solubilization of a North Dakota leonardite. It was found that a concentration {approximately}75 mM sodium oxalate was optimal for solubilization of this low rank coal. This is important because this is well above the concentration of oxalate produced by fungi in liquid culture. Higher local concentrations probably occur in solid agar cultures and thus may account for the observation that greater solubilization occurs in agar media relative to liquid media. The characteristics of biomimetically solubilized leonardite were similar to those of biologically solubilized leonardite. Perhaps our most interesting observation was that in addition to oxalate, other common Lewis bases (phosphate/hydrogen phosphate/dihydrogen phosphate and bicarbonate/carbonate ions) are able to mediate substantial solubilization of leonardite at physiological pH values. Lastly, we present evidence that some fungi appear to possess coal solubilization ability in which the initial events of solubilization is not mediated by oxalate ion.« less

Evaluation of heavy metal leaching from coal ash-versus conventional concrete monoliths and debris.

PubMed

Gwenzi, Willis; Mupatsi, Nyarai M

2016-03-01

Application of coal ash in construction materials is constrained by the potential risk of heavy metal leaching. Limited information is available on the comparative heavy metal leaching from coal ash-versus conventional concrete. The current study compared total and leached heavy metal concentrations in unbound coal ash, cement and sand; and investigated the effect of initial leachant pH on heavy metal leaching from coal-ash versus conventional concrete monoliths and their debris. Total Pb, Mn and Zn in coal ash were lower than or similar to that of other materials, while Cu and Fe showed the opposite trend. Leached concentrations of Zn, Pb, Mn, Cu and Fe in unbound coal ash, its concrete and debris were comparable and in some cases even lower than that for conventional concrete. In all cases, leached concentrations accounted for just <1% of the total concentrations. Log-log plots of concentration and cumulative release of Fe versus time based on tank leaching data showed that leaching was dominated by diffusion. Overall, the risk of Zn, Pb, Mn, Cu and Fe leaching from coal ash and its concrete was minimal and comparable to that of conventional concrete, a finding in contrast to widely held public perceptions and earlier results reported in other regions such as India. In the current study the coal ash, and its concrete and debris had highly alkaline pH indicative of high acid neutralizing and pH buffering capacity, which account for the stabilization of Zn, Pb, Mn, Cu and Fe. Based on the low risk of Zn, Pb, Mn, Cu and Fe leaching from the coal ash imply that such coal ash can be incorporated in construction materials such as concrete without adverse impacts on public and environmental health from these constituents. Copyright © 2015 Elsevier Ltd. All rights reserved.

Experimental analysis of multiple factors on hydraulic fracturing in coalbed methane reservoirs

PubMed Central

Ma, Geng; Liu, Xiao; Tao, Yunqi; Feng, Dan; Li, Rui

2018-01-01

Hydraulic fracturing can improve the permeability of coalbed methane (CBM) reservoirs effectively, which is of great significance to the commercial production of CBM. However, the efficiency of hydraulic fracturing is affected by multiple factors. The mechanism of fracture initiation, morphology and propagation in CBM reservoirs is not clear and need to be further explored. Hydraulic fracturing experiment is an accurate tool to explore these mechanisms. The quantity of experimental coal rock is large and processing method is complex, so specimen made of similar materials was applied to replace coal rock. The true triaxial hydraulic fracturing experimental apparatus, 3D scanning device for coal rock section were applied to carry out hydraulic fracturing experiment. The results show that the initiation pressure is inversely proportional to the horizontal stress difference (Δσ) and positively related to fracturing fluid injection rate. When vertical stress (σv) is constant, the initiation pressure and fracture width decrease with the increasing of Δσ. Natural fractures can be connected by main fracture when propagates perpendicular to the direction of minimum horizontal stress (σh), then secondary fractures and fracture network form in CBM reservoirs. When two stresses of crustal stress are close and far different from the third one, the fracture morphology and propagation become complex. Influenced by perforations and filtration of fracturing fluid in specimen, fracturing fluid flows to downward easily after comparing horizontal well fracturing with vertical well fracturing. Fracture width increases with the decreasing of elastic modulus, the intensity of fracture is positively related with the elastic modulus of coal rock. The research results can provide theoretical basis and technical support for the efficient development of CBM. PMID:29621295

Experimental analysis of multiple factors on hydraulic fracturing in coalbed methane reservoirs.

PubMed

Zhang, Fan; Ma, Geng; Liu, Xiao; Tao, Yunqi; Feng, Dan; Li, Rui

2018-01-01

Hydraulic fracturing can improve the permeability of coalbed methane (CBM) reservoirs effectively, which is of great significance to the commercial production of CBM. However, the efficiency of hydraulic fracturing is affected by multiple factors. The mechanism of fracture initiation, morphology and propagation in CBM reservoirs is not clear and need to be further explored. Hydraulic fracturing experiment is an accurate tool to explore these mechanisms. The quantity of experimental coal rock is large and processing method is complex, so specimen made of similar materials was applied to replace coal rock. The true triaxial hydraulic fracturing experimental apparatus, 3D scanning device for coal rock section were applied to carry out hydraulic fracturing experiment. The results show that the initiation pressure is inversely proportional to the horizontal stress difference (Δσ) and positively related to fracturing fluid injection rate. When vertical stress (σv) is constant, the initiation pressure and fracture width decrease with the increasing of Δσ. Natural fractures can be connected by main fracture when propagates perpendicular to the direction of minimum horizontal stress (σh), then secondary fractures and fracture network form in CBM reservoirs. When two stresses of crustal stress are close and far different from the third one, the fracture morphology and propagation become complex. Influenced by perforations and filtration of fracturing fluid in specimen, fracturing fluid flows to downward easily after comparing horizontal well fracturing with vertical well fracturing. Fracture width increases with the decreasing of elastic modulus, the intensity of fracture is positively related with the elastic modulus of coal rock. The research results can provide theoretical basis and technical support for the efficient development of CBM.

Initiation, Combustion and Transition to Detonation in Homogeneous and Heterogeneous Reactive Mixtures: A Summary

DTIC Science & Technology

1981-09-01

undoubtedly associ- uid expanding-vapor explosions, or’ course of an explosion. In buildings ated with the manufacture, handling, BLEVEs , and unconfined...with its need for fossil fuel away, owing to atmospheric inhomo- energy, introduced coal mine explo- geneities, it is heard as a "boom." The blast wave...1947, when the fuels in enclosures compressed-air lines ship Grand Camp caught fire Combustion explosions of dusts In enclosures Coal mines , grain

Change of brown coal oxidation kinetic characteristics by promoting additives appending in the form of copper salts

NASA Astrophysics Data System (ADS)

Larionov, K. B.; Mishakov, I. V.; Gromov, A. A.; Zenkov, A. V.

2017-11-01

Process of brown coal oxidation with 5%wt content of copper-salt additives of various nature (Cu (NO3)2, CuSO4 and Cu(CH3COO)2) was studied. The experiment has been performed by thermogravimetric analysis at a heating rate of 2.5°C/min to a maximum temperature of 600°C in the air. Analytical evaluation of oxidation process kinetic characteristics has been conducted based on the results of TGA. It has been established that addition of initiating agents leads to significant reduction in the initial ignition temperature of coal (ΔTi = 15÷40°C), shortening of the sample warm-up time to the ignition point (Δte = 6÷12 min) and reduction of the sample burning time (Δtf = 40÷54 min). The following series of additives activity affecting ignition temperature of coals has been established: Cu(CH3COO)2 > Cu(NO3)2 > CuSO4. Additionally, the opposite can be said about the effect of additives on residence time of the sample in its combustion area (CuSO4 > Cu(NO3)2 > Cu(CH3COO)2). According to mass spectrometric analysis, presence of NOx, SO2, CO2 (intense peaks at 190÷290°C) was recorded in oxidation products of modified samples, which is explained by partial or complete decomposition of salts.

Microfine coal firing results from a retrofit gas/oil-designed industrial boiler

DOE Office of Scientific and Technical Information (OSTI.GOV)

Patel, R.; Borio, R.W.; Liljedahl, G.

1995-12-31

The development of a High Efficiency Advanced Coal Combustor (HEACC) has been in progress since 1987 and the ABB Power Plant Laboratories. The initial work on this concept produced an advanced coal firing system that was capable of firing both water-based and dry pulverized coal in an industrial boiler environment. Economics may one day dictate that it makes sense to replace oil or natural gas with coal in boilers that were originally designed to burn these fuels. The objective of the current program is to demonstrate the technical and economic feasibility of retrofitting a gas/oil designed boiler to burn micronizedmore » coal. In support of this overall objective, the following specific areas were targeted: A coal handling/preparation system that can meet the technical requirements for retrofitting microfine coal on a boiler designed for burning oil or natural gas; Maintaining boiler thermal performance in accordance with specifications when burning oil or natural gas; Maintaining NOx emissions at or below 0.6 lb/MBtu; Achieving combustion efficiencies of 98% or higher; and Calculating economic payback periods as a function of key variables. The overall program has consisted of five major tasks: (1) A review of current state-of-the-art coal firing system components; (2) Design and experimental testing of a prototype HEACC burner; (3) Installation and testing of a HEACC system in a commercial retrofit application; (4) Economic evaluation of the HEACC concept for retrofit applications; and (5) Long term demonstration under commercial user demand conditions. This paper will summarize the latest key experimental results (Task 3) and the economic evaluation (Task 4) of the HEACC concept for retrofit applications. 28 figs., 6 tabs.« less

Kinetics of scheelite dissolution in groundwater: defining the release rate of tungsten contamination from a natural source

NASA Astrophysics Data System (ADS)

Montgomery, S. D.; Mckibben, M. A.

2011-12-01

Tungsten, an emerging contaminant, has no EPA standard for its permissible levels in drinking water. At sites in California, Nevada, and Arizona there may be a correlation between elevated levels of tungsten in drinking water and clusters of childhood acute lymphocytic leukemia (ALL). Developing a better understanding of how tungsten is released from rocks into surface and groundwaters is therefore of growing environmental interest. Knowledge of tungstate ore mineral weathering processes, particularly the rates of dissolution of scheelite (CaWO4) in groundwater, could improve models of how tungsten is released and transported in natural waters. Our research is focusing on experimental determination of the rates and products of tungstate mineral dissolution in synthetic groundwater, as a function of temperature, pH and mineral surface area. The initial rate method is being used to develop rate laws. Batch reactor experiments are conducted within constant temperature circulation baths over a pH range of 2-9. Cleaned scheelite powder with grain diameters of 106-150um is placed between two screens in a sample platform and then placed inside a two liter Teflon vessel filled with synthetic groundwater. Ports on the vessel allow sample extraction, temperature and pH measurement, gas inflow, and water circulation. Aliquots of solution are taken periodically for product analysis by ICP -MS. Changes in mineral surface characteristics are monitored using SEM and EDS methods. Results so far reveal that the dissolution of scheelite is incongruent at both neutral and low pH. Solid tungstic acid forms on scheelite mineral surfaces under acidic conditions, implying that this phase controls the dissolution rate in acidic environments. The influence of dissolved CO2 and resultant calcium carbonate precipitation on the dissolution of scheelite at higher pH is also being investigated. The rate law being developed for scheelite dissolution will be useful in reactive-transport computer codes designed to model tungsten contamination in a variety of surface and groundwater settings.

The temporal evolution of magnesium isotope fractionation during hydromagnesite dissolution, precipitation, and at equilibrium

NASA Astrophysics Data System (ADS)

Oelkers, Eric H.; Berninger, Ulf-Niklas; Pérez-Fernàndez, Andrea; Chmeleff, Jérôme; Mavromatis, Vasileios

2018-04-01

This study provides experimental evidence of the resetting of the magnesium (Mg) isotope signatures of hydromagnesite in the presence of an aqueous fluid during its congruent dissolution, precipitation, and at equilibrium at ambient temperatures over month-long timescales. All experiments were performed in batch reactors in aqueous sodium carbonate buffer solutions having a pH from 7.8 to 9.2. The fluid phase in all experiments attained bulk chemical equilibrium within analytical uncertainty with hydromagnesite within several days, but the experiments were allowed to continue for up to 575 days. During congruent hydromagnesite dissolution, the fluid first became enriched in isotopically light Mg compared to the dissolving hydromagnesite, but this Mg isotope composition became heavier after the fluid attained chemical equilibrium with the mineral. The δ26Mg composition of the fluid was up to ∼0.35‰ heavier than the initial dissolving hydromagnesite at the end of the dissolution experiments. Hydromagnesite precipitation was provoked during one experiment by increasing the reaction temperature from 4 to 50 °C. The δ26Mg composition of the fluid increased as hydromagnesite precipitated and continued to increase after the fluid attained bulk equilibrium with this phase. These observations are consistent with the hypothesis that mineral-fluid equilibrium is dynamic (i.e. dissolution and precipitation occur at equal, non-zero rates at equilibrium). Moreover the results presented in this study confirm (1) that the transfer of material from the solid to the fluid phase may not be conservative during stoichiometric dissolution, and (2) that the isotopic compositions of carbonate minerals can evolve even when the mineral is in bulk chemical equilibrium with its coexisting fluid. This latter observation suggests that the preservation of isotopic signatures of carbonate minerals in the geological record may require a combination of the isolation of fluid-mineral system from external chemical input and/or the existence of a yet to be defined dissolution/precipitation inhibition mechanism.

Hierarchical zeolites from class F coal fly ash

NASA Astrophysics Data System (ADS)

Chitta, Pallavi

Fly ash, a coal combustion byproduct is classified as types class C and class F. Class C fly ash is traditionally recycled for concrete applications and Class F fly ash often disposed in landfills. Class F poses an environmental hazard due to disposal and leaching of heavy metals into ground water and is important to be recycled in order to mitigate the environmental challenges. A major recycling option is to reuse the fly ash as a low-cost raw material for the production of crystalline zeolites, which serve as catalysts, detergents and adsorbents in the chemical industry. Most of the prior literature of fly ash conversion to zeolites does not focus on creating high zeolite surface area zeolites specifically with hierarchical pore structure, which are very important properties in developing a heterogeneous catalyst for catalysis applications. This research work aids in the development of an economical process for the synthesis of high surface area hierarchical zeolites from class F coal fly ash. In this work, synthesis of zeolites from fly ash using classic hydrothermal treatment approach and fusion pretreatment approach were examined. The fusion pretreatment method led to higher extent of dissolution of silica from quartz and mullite phases, which in turn led to higher surface area and pore size of the zeolite. A qualitative kinetic model developed here attributes the difference in silica content to Si/Al ratio of the beginning fraction of fly ash. At near ambient crystallization temperatures and longer crystallization times, the zeolite formed is a hierarchical faujasite with high surface area of at least 360 m2/g. This work enables the large scale recycling of class F coal fly ash to produce zeolites and mitigate environmental concerns. Design of experiments was used to predict surface area and pore sizes of zeolites - thus obviating the need for intense experimentation. The hierarchical zeolite catalyst supports tested for CO2 conversion, yielded hydrocarbons up to C9, a performance attesting the hierarchal pore structure. The preliminary techno-economic feasibility assessment demonstrates a net energy saving of 75% and cost saving of 63% compared to the commercial zeolite manufacturing process.

Selenium content and oxidation states in fly ashes from western U.S. coals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mattigod, Shas V; Quinn, Thomas R

2003-08-01

A selective extraction scheme was developed for the determination of the oxidation states of Se species in coal ashes. As compared to HF dissolution, extractions with 70% HC1O4 mobilized 90 to 100% of all compound and redox forms of Se from four of the five fly ashes. Extractions with 16M HNO3 did not mobilize all forms of Se as effectively as perchloric acid. Both oxidized forms of Se (IV and VI) were completely mobilized by 12M HCl extraction. Deionized-distilled water was not an effective extractant for mobilizing all compound forms of Se(IV) from fly ashes. Extraction data (70% HClO4, 16Mmore » HNO3, 12M HCl, DI water) indicated that the solid:solution ratio is a critical factor in Se extractability from fly ashes. Maximum extractions in all cases were obtained only with very high (1:500) solid:solution ratios. Extraction times from 1.5 to 25 hours did not significantly change Se extractability with any of the extractants except with 12M HCl, which required a minimum reaction time of 48 hours to attain maximum Se extractability. Reaction times shorter than the critical time and low solid:solution ratios significantly affected Se extractability from these fly ashes. Measurements of Se content and redox state in particle size and density fractions five western United States coal ashes indicated that typically, the Se content increased with decreasing particle size.. However, no consistent trend in Se concentration between the light and heavy density fractions of <2.7-m size fraction was observed. Selenium redox state data indicated that only Se(0) and Se(IV) forms were present in these five coal ashes. The presence of Se(IV) is significant since it is much more easily mobilized than the elemental form. Examination of fly ashes by the proposed scheme to determine Se redox species could permit better estimation of the Se content of plants grown on fly ash amended soils.« less

The effects of ion identity and ionic strength on the dissolution rate of a gibbsitic bauxite

NASA Astrophysics Data System (ADS)

Mogollón, José Luis; Pérez-Diaz, Alberto; Lo Monaco, Salvador

2000-03-01

The influence of cation and anion identity and concentration, on the far from equilibrium dissolution rate of gibbsite, was studied at 298°K. Input solutions, with initial pH = 3.5 and variable salt type and concentration, were flowed at different rates, through columns packed with a unconsolidated gibbsitic bauxite from Los Pijigüaos-Venezuela ore deposit. It was observed cations Na +, K +, Mg 2+ and Ca2+ have no influence on the far from equilibrium dissolution rate. Anions have two different effects: concentration increases of monovalent anions (Cl -, NO 3- and ClO 4-) causes a decrease in the rate, as a function of [anion] (-0.11 ± 0.01); and increases of sulfate concentration causes an increase in the rate as a function of [SO 4=] (0.4 ± 0.1). According to our calculations, these two effects have a remarkable influence upon the lifetime of gibbsite under weathering conditions. Based on Transition State Theory, it is proposed the experimental observations are due to an electrostatic effect on the activated complex (AC ♯) of the gibbsite dissolution reaction. For this AC ♯ the product of the charge of the involved chemical entities is negative. When SO 4= participates in the AC ♯ the product of the charges switches to positive and therefore, the electrostatic interaction increase the dissolution rate. The dissolution rates are independent of the solution saturation degree below ΔGr = - 0.74 kcal/mol. It is inferred that the critical ΔGr is a constant of the solid, not affected by the solution characteristics, e.g., pH, ionic strength, cation and anion identities.

Improving Crotalidae polyvalent immune Fab reconstitution times.

PubMed

Quan, Asia N; Quan, Dan; Curry, Steven C

2010-06-01

Crotalidae polyvalent immune Fab (CroFab) is used to treat rattlesnake envenomations in the United States. Time to infusion may be a critical factor in the treatment of these bites. Per manufacturer's instructions, 10 mL of sterile water for injection (SWI) and hand swirling are recommended for reconstitution. We wondered whether completely filling vials with 25 mL of SWI would result in shorter reconstitution times than using 10-mL volumes and how hand mixing compared to mechanical agitation of vials or leaving vials undisturbed. Six sets of 5 vials were filled with either 10 mL or 25 mL. Three mixing techniques were used as follows: undisturbed; agitation with a mechanical agitator; and continuous hand rolling and inverting of vials. Dissolution was determined by observation and time to complete dissolution for each vial. Nonparametric 2-tailed P values were calculated. Filling vials completely with 25 mL resulted in quicker dissolution than using 10-mL volumes, regardless of mixing method (2-tailed P = .024). Mixing by hand was shorter than other methods (P < .001). Reconstitution with 25 mL and hand mixing resulted in the shortest dissolution times (median, 1.1 minutes; range, 0.9-1.3 minutes). This appeared clinically important because dissolution times using 10 mL and mechanical rocking of vials (median, 26.4 minutes) or leaving vials undisturbed (median, 33.6 minutes) was several-fold longer. Hand mixing after filling vials completely with 25 mL results in shorter dissolution times than using 10 mL or other methods of mixing and is recommended, especially when preparing initial doses of CroFab. Copyright (c) 2010 Elsevier Inc. All rights reserved.

Numerical modeling of mineral dissolution - precipitation kinetics integrating interfacial processes

NASA Astrophysics Data System (ADS)

Azaroual, M. M.

2016-12-01

The mechanisms of mineral dissolution/precipitation are complex and interdependent. Within a same rock, the geochemical modelling may have to manage kinetic reactions with high ratios between the most reactive minerals (i.e., carbonates, sulfate salts, etc.) and less reactive minerals (i.e., silica, alumino-silicates, etc.). These ratios (higher than 10+6) induce numerical instabilities for calculating mass and energy transfers between minerals and aqueous phases at the appropriate scales of time and space. The current scientific debate includes: i) changes (or not) of the mineral reactive surface with the progress of the dissolution/precipitation reactions; ii) energy jumps (discontinuity) in the thermodynamic affinity function of some dissolution/precipitation reactions and iii) integration of processes at the "mineral - aqueous solution" interfaces for alumino-silicates, silica and carbonates. In recent works dealing with the specific case of amorphous silica, measurements were performed on nano-metric cross-sections indicating the presence of surface layer between the bulk solution and the mineral. This thin layer is composed by amorphous silica and hydrated silica "permeable" to the transfer of water and ionic chemical constituents. The boundary/interface between the initial mineral and the silica layer is characterized by a high concentration jump of chemical products at the nanoscale and some specific interfacial dissolution/precipitation processes.In this study, the results of numerical simulations dealing with different mechanisms of silicate and carbonate dissolution/precipitation reactions and integrating interfacial processes will be discussed. The application of this approach to silica precipitation is based on laboratory experiments and it highlights the significant role of the "titration" surface induced by surface complexation reactions in the determination of the kinetics of precipitation.

The chemical composition of tertiary Indian coal ash and its combustion behaviour - a statistical approach: Part 2

NASA Astrophysics Data System (ADS)

Sharma, Arpita; Saikia, Ananya; Khare, Puja; Dutta, D. K.; Baruah, B. P.

2014-08-01

In Part 1 of the present investigation, 37 representative Eocene coal samples of Meghalaya, India were analyzed and their physico-chemical characteristics and the major oxides and minerals present in ash samples were studied for assessing the genesis of these coals. Various statistical tools were also applied to study their genesis. The datasets from Part 1 used in this investigation (Part 2) show the contribution of major oxides towards ash fusion temperatures (AFTs). The regression analysis of high temperature ash (HTA) composition and initial deformation temperature (IDT) show a definite increasing or decreasing trend, which has been used to determine the predictive indices for slagging, fouling, and abrasion propensities during combustion practices. The increase or decrease of IDT is influenced by the increase of Fe2O3, Al2O3, SiO2, and CaO, respectively. Detrital-authigenic index (DAI) calculated from the ash composition and its relation with AFT indicates Sialoferric nature of these coals. The correlation analysis, Principal Component Analysis (PCA), and Hierarchical Cluster Analysis (HCA) were used to study the possible fouling, slagging, and abrasion potentials in boilers during the coal combustion processes. A positive relationship between slagging and heating values of the coal has been found in this study.

75 FR 68570 - Approval and Disapproval and Promulgation of Air Quality Implementation Plans; Colorado; Revision...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-11-08

... and with current Federal NSR regulations. These definitions include clean coal technology, electric... restrictions on increment consumption, add innovative control technology as an alternative to BACT requirements... initials RACT mean or refer to Reasonably Available Control Technology, and the initials NAAQS mean or...

A conversion of CO2-ECBM related lab observations to reservoir requirements

NASA Astrophysics Data System (ADS)

Gensterblum, Y.; Merkel, A.; Busch, A.; Krooss, B. M.

2012-04-01

To predict a CBM production profile either during primary or secondary production, aspects like coal permeability and porosity, density, ash and moisture content, initial gas-in-place (GIP) (from canister desorption tests), gas sorption capacity from laboratory isotherms (to obtain gas saturations and desorption pressure), gas diffusivities, coal volumetrics (thickness and areal extent) need to be understood as a minimum requirement. When dealing with CO2-ECBM selective adsorption, counter diffusion in the coal matrix, or coal shrinkage and swelling (from CH4 desorption and CO2 adsorption, respectively) and the influence of moisture need to be investigated in addition to the parameters above. During CO2-ECBM processes, the areal distribution of the CO2 injected is accomplished by flow through the cleat network. When CO2 is entering the coal matrix by a combined sorption/diffusion process it will adsorb to the coal inner surface and at the same time replace part of the CH4. This replacement occurs either by a reduction in the CH4 partial pressure or by a higher selective sorption of CO2 over CH4. Because of a concentration gradient between CH4 in the matrix compared to the cleat system, CH4 diffuses from the coal matrix into the cleat system where, by pressure drawdown towards a production well, it can be produced. In this context this presentation summarizes gas (CO2, CH4) and water sorption on coal and specifically addresses the following topics: • CH4 and CO2 sorption capacity as a function depth and rank • CO2 and CH4 sorption on natural coals and its dependence on coal specific parameters like coal rank, maceral composition or ash content (Busch and Gensterblum, 2011). • Water sorption on coal, its dependence on coal properties such as rank and coal chemistry and gas sorption in the presence of water (Busch and Gensterblum, 2011). • N2, CH4, CO2 displacement experiments and the volumetric response of the coal on the present gas type (sorbing or inert) in the pore system • Uncertainties in reservoir characterisation (Gensterblum et al., 2010; Gensterblum et al., 2009) • Sorption uptake kinetic as a function of surface coverage and the influence of moisture on the kinetic Busch, A. and Gensterblum, Y., 2011. CBM and CO2-ECBM related sorption processes in coal: A review. International Journal of Coal Geology, 87: 49-71. Gensterblum, Y. et al., 2010. European inter-laboratory comparison of high pressure CO2 sorption isotherms II: Natural coals. International Journal of Coal Geology, 84(2): 115-124. Gensterblum, Y. et al., 2009. European inter-laboratory comparison of high pressure CO2 sorption isotherms. I: Activated carbon. Carbon, 47(13): 2958-2969.

Studies of angiospermous woods in Australian brown coal by nuclear magnetic resonance and analytical pyrolysis: new insight into early coalification

USGS Publications Warehouse

Hatcher, P.G.; Wilson, M.A.; Vassalo, M.; Lerch, H. E.

1990-01-01

Many Tertiary coals contain abundant fossilized remains of angiosperms that often dominated some ancient peat-swamp environments; modern analogs of which can be found in tropical and subtropical regions of the world. Comparisons of angiospermous woods from Australian brown coal with similar woods buried in modern peat swamps of Indonesia have provided some new insights into coalification reactions. These comparisons were made by using solid-state 13C nuclear magnetic resonance (NMR) techniques and pyrolysis-gas chromatography-mass spectrometry (py-gc-ms), two modern techniques especially suited for detailed structural evaluation of the complex macromolecules in coal. From these studies, we conclude that the earliest transformation (peatification) of organic matter in angiospermous wood is the degradation of cellulosic components. The efficiency of removal of cellulosic components in the wood varies considerably in peat, which results in variable levels of cellulose in peatified wood. However, the net trend is towards eventual removal of the cellulose. The angiospermous lignin that becomes enriched in wood as a result of cellulose degradation also is modified by coalifications reactions; this modification, however, does not involve degradation and removal. Rather, the early coalification process transforms the lignin phenols (guaiacyl and syringyl) to eventually yield the aromatic structures typically found in brown coal. One such transformation, which is determined from the NMR data, involves the cleavage of aryl ether bonds that link guaiacyl and syringyl units in lignin and leads to the formation of free lignin phenols. Another transformation, which is also determined from the NMR data, involves the loss of methoxyl groups, probably via demethylation, to produce catechol-like structures. Coincident with ether-cleavage and demethylation, the aromatic rings derived from lignin phenols become more carbon-substituted and cross-linked, as determined by dipolar-dephasing NMR studies. This cross-linking is probably responsible for preventing the lignin phenols, which are freed from the lignin macromolecule by ether cleavage and from being removed from the coal by dissolution. Pyrolysis data suggest that the syringyl units are altered more readily than are guaiacyl units, which leads to an enrichment of the guaiacyl units in fossil angiospermous woods. Although many of the coalification reactions noted above occur to some degree in all angiospermous fossil woods examined, some significant differences are observed in the degree of coalification of the fossil woods from the same burial depth in the brown coal. This indicates that the depth and the duration of burial are probably not entirely responsible for the variations in degree of coalification. It is likely that different rates of degradation in peat may have contributed to the variations in the apparent degree of coalification, considering the fact that some woods may have been altered more rapidly at the peat stage than others. Although preliminary, it is clear that a systematic study of botanically related woods in peat and coal leads to a more detailed differentiation of coalification reactions than have previous investigations. The combined use of solid-state 13C NMR and py-gc-ms has facilitated this detailed new insight into coalification of angiospermous wood. ?? 1990.

Dissolution kinetics of a lunar glass simulant at 25 degrees C: the effect of pH and organic acids

NASA Technical Reports Server (NTRS)

Eick, M. J.; Grossl, P. R.; Golden, D. C.; Sparks, D. L.; Ming, D. W.

1996-01-01

The dissolution kinetics of a simulated lunar glass were examined at pH 3, 5, and 7. Additionally, the pH 7 experiments were conducted in the presence of citric and oxalic acid at concentrations of 2 and 20 mM. The organic acids were buffered at pH 7 to examine the effect of each molecule in their dissociated form. At pH 3, 5, and 7, the dissolution of the synthetic lunar glass was observed to proceed via a two-stage process. The first stage involved the parabolic release of Ca, Mg, Al, and Fe, and the linear release of Si. Dissolution was incongruent, creating a leached layer rich in Si and Ti which was verified by transmission electron microscopy (TEM). During the second stage the release of Ca, Mg, Al, and Fe was linear. A coupled diffusion/surface dissolution model was proposed for dissolution of the simulated lunar glass at pH 3, 5, and 7. During the first stage the initial release of mobile cations (i.e., Ca, Mg, Al, Fe) was limited by diffusion through the surface leached layer of the glass (parabolic release), while Si release was controlled by the hydrolysis of the Si-O-Al bonds at the glass surface (linear release). As dissolution continued, the mobile cations diffused from greater depths within the glass surface. A steady-state was then reached where the diffusion rate across the increased path lengths equalled the Si release rate from the surface. In the presence of the organic acids, the dissolution of the synthetic lunar glass proceeded by a one stage process. The release of Ca, Mg, Al, and Fe followed a parabolic relationship, while the release of Si was linear. The relative reactivity of the organic acids used in the experiments was citrate > oxalate. A thinner leached layer rich in Si/Ti, as compared to the pH experiments, was observed using TEM. Rate data suggest that the chemisorption of the organic anion to the surface silanol groups was responsible for enhanced dissolution in the presence of the organic acids. It is proposed that the increased rate of Si release is responsible for the one stage parabolic release of mobile cations and the relatively thin leached layer compared to experiments at pH 3 and 5.

Evolution of Abnormally Low Pressure at Bravo Dome and its Implications for Carbon Capture and Storage (CCS)

NASA Astrophysics Data System (ADS)

Akhbari, D.; Hesse, M. A.

2015-12-01

Carbon capture and storage allows reductions of the rapidly rising CO2 from fossil fuel-based power generation, if large storage rates and capacities can be achieved. The injection of large fluid volumes at high rates leads to a build-up of pore-pressure in the storage formation that may induce seismicity and compromise the storage security. Many natural CO2 fields in midcontinent US, in contrast, are under-pressured rather than over-pressured suggesting that natural processes reduce initial over-pressures and generate significant under-pressures. The question is therefore to understand the sequence of process(es) that allow the initial over-pressure to be eliminated and the under-pressure to be maintained over geological periods of time. We therefore look into pressure evolution in Bravo Dome, one of the largest natural CO2 accumulations in North America, which stores 1.3 Gt of CO2. Bravo Dome is only 580-900 m deep and is divided into several compartments with near gas-static pressure (see Figure). The pre-production gas pressures in the two main compartments that account for 70% of the mass of CO2 stored at Bravo Dome are more than 6 MPa below hydrostatic pressure. Here we show that the under-pressure in the Bravo Dome CO2 reservoir is maintained by hydrological compartmentalization over millennial timescales and generated by a combination of processes including cooling, erosional unloading, limited leakage into overlying formations, and CO2 dissolution into brine. Herein, we introduce CO2 dissolution into brine as a new process that reduce gas pressure in a compartmentalized reservoir and our results suggest that it may contribute significantly to reduce the initial pressure build-up due to injection. Bravo Dome is the first documented case of pressure drop due to CO2 dissolution. To have an accurate prediction of pressure evolution in Bravo Dome, our models must include geomechanics and thermodynamics for the reservoir while they account for the pressure changes due to the CO2 dissolution.

Numerical study of bituminous coal combustion in a boiler furnace with bottom blowing

NASA Astrophysics Data System (ADS)

Zroychikov, N. A.; Kaverin, A. A.

2016-11-01

Results obtained by the numerical study of a solid fuel combustion scheme with bottom blowing using Ekibastuz and Kuznetsk bituminous coals of different fractional makeup are presented. Furnace chambers with bottom blowing provide high-efficiency combustion of coarse-grain coals with low emissions of nitrogen oxides. Studying such a combustion scheme, identification of its technological capabilities, and its further improvement are topical issues. As the initial object of study, we selected P-57-R boiler plant designed for burning of Ekibastuz bituminous coal in a prismatic furnace with dry-ash (solid slag) removal. The proposed modernization of the furnace involves a staged air inflow under the staggered arrangement of directflow burners (angled down) and bottom blowing. The calculation results revealed the specific aerodynamics of the flue gases, the trajectories of solid particles in the furnace chamber, and the peculiarities of the fuel combustion depending on the grinding fineness. It is shown that, for coal grinding on the mill, the overall residue on the screen plate of 90 µm ( R 90 ≤ 27% for Ekibastuz coal and R 90 ≤ 15% for Kuznetsk coal) represents admissible values for fuel grind coarsening in terms of economic efficiency and functional reliability of a boiler. The increase in these values leads to the excess of regulatory heat losses and unburned combustible losses. It has been established that the change in the grade of the burned coal does not significantly affect the flow pattern of the flue gases, and the particles trajectory is essentially determined by the elemental composition of the fuel.

A drowned lycopsid forest above the Mahoning coal (Conemaugh Group, Upper Pennsylvanian) in eastern Ohio, U.S.A

USGS Publications Warehouse

DiMichele, W.A.; Eble, C.F.; Chaney, D.S.

1996-01-01

Over 800 mud-filled casts of upright lycopsid tree stumps have been documented immediately above the Mahoning coal in an active underground mine located in northwestern Jefferson County, Ohio. The coal body originated as a pod-shaped peat body of ??? 60 km2. Trees are rooted at several levels within a thin (15-40 cm) bone coal directly above the banded coal; they extend upward up to 15 cm into overlying, flat-bedded, carbonaceous mudstones that coarsen up. From a maximum basal diameter of 1.2 m, stumps taper upward to diameters no less than 0.3 m. Within single-entry transects, < 6 m wide that total 2585 m in length, stumps are randomly distributed. The trees are identified as lepidodendrids on the basis of gross morphology, external stem patterns, and attached stigmarian root systems, and provisionally as Lepidophloios or Lepidodendron by associated palynology of the enclosing matrix. Palynological analyses of incremental seam samples indicate an initial dominance of lycopsid spores with lepidodendracean affinities (Lycospora granulata from Lepidophloios hallii), replaced upwards by tree-fern spores, with a reoccurrence of lepidodendracean spores in the upper benches; spores of Sigillaria (Crassispora) are abundant only at the base of the coal. Petrographic analyses indicate a parallel trend from vitrinite-rich to inertinite- and liptinite-rich upward in the coal body. All data indicate that the peat represented by the Mahoning coal was drowned slowly. During the earliest stages of inundation, a lycopsid forest was re-established, only to be subsequently drowned.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Plemons, R.E.; Hopwood, W.H. Jr.; Hamilton, J.H.

For a number of years the Oak Ridge Y-12 Plant Laboratory has been analyzing coal predominately for the utilities department of the Y-12 Plant. All laboratory procedures, except a Leco sulfur method which used the Leco Instruction Manual as a reference, were written based on the ASTM coal analyses. Sulfur is analyzed at the present time by two methods, gravimetric and Leco. The laboratory has two major endeavors for monitoring the quality of its coal analyses. (1) A control program by the Plant Statistical Quality Control Department. Quality Control submits one sample for every nine samples submitted by the utilitiesmore » departments and the laboratory analyzes a control sample along with the utilities samples. (2) An exchange program with the DOE Coal Analysis Laboratory in Bruceton, Pennsylvania. The Y-12 Laboratory submits to the DOE Coal Laboratory, on even numbered months, a sample that Y-12 has analyzed. The DOE Coal Laboratory submits, on odd numbered months, one of their analyzed samples to the Y-12 Plant Laboratory to be analyzed. The results of these control and exchange programs are monitored not only by laboratory personnel, but also by Statistical Quality Control personnel who provide statistical evaluations. After analysis and reporting of results, all utilities samples are retained by the laboratory until the coal contracts have been settled. The utilities departments have responsibility for the initiation and preparation of the coal samples. The samples normally received by the laboratory have been ground to 4-mesh, reduced to 0.5-gallon quantities, and sealed in air-tight containers. Sample identification numbers and a Request for Analysis are generated by the utilities departments.« less

CO2, CO, and Hg emissions from the Truman Shepherd and Ruth Mullins coal fires, eastern Kentucky, USA

USGS Publications Warehouse

O'Keefe, Jennifer M.K.; Henke, Kevin R.; Hower, James C.; Engle, Mark A.; Stracher, Glenn B.; Stucker, J.D.; Drew, Jordan W.; Staggs, Wayne D.; Murray, Tiffany M.; Hammond, Maxwell L.; Adkins, Kenneth D.; Mullins, Bailey J.; Lemley, Edward W.

2010-01-01

Carbon dioxide (CO2), carbon monoxide (CO), and mercury (Hg) emissions were quantified for two eastern Kentucky coal-seam fires, the Truman Shepherd fire in Floyd County and the Ruth Mullins fire in Perry County. This study is one of the first to estimate gas emissions from coal fires using field measurements at gas vents. The Truman Shepherd fire emissions are nearly 1400 t CO2/yr and 16 kg Hg/yr resulting from a coal combustion rate of 450–550 t/yr. The sum of CO2 emissions from seven vents at the Ruth Mullins fire is 726 ± 72 t/yr, suggesting that the fire is consuming about 250–280 t coal/yr. Total Ruth Mullins fire CO and Hg emissions are estimated at 21 ± 1.8 t/yr and > 840 ± 170 g/yr, respectively. The CO2emissions are environmentally significant, but low compared to coal-fired power plants; for example, 3.9 × 106 t CO2/yr for a 514-MW boiler in Kentucky. Using simple calculations, CO2 and Hg emissions from coal-fires in the U.S. are estimated at 1.4 × 107–2.9 × 108 t/yr and 0.58–11.5 t/yr, respectively. This initial work indicates that coal fires may be an important source of CO2, CO, Hg and other atmospheric constituents.

Catalytic multi-stage liquefaction of coal at HTI: Bench-scale studies in coal/waste plastics coprocessing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pradhan, V.R.; Lee, L.K.; Stalzer, R.H.

1995-12-31

The development of Catalytic Multi-Stage Liquefaction (CMSL) at HTI has focused on both bituminous and sub-bituminous coals using laboratory, bench and PDU scale operations. The crude oil equivalent cost of liquid fuels from coal has been curtailed to about $30 per barrel, thus achieving over 30% reduction in the price that was evaluated for the liquefaction technologies demonstrated in the late seventies and early eighties. Contrary to the common belief, the new generation of catalytic multistage coal liquefaction process is environmentally very benign and can produce clean, premium distillates with a very low (<10ppm) heteroatoms content. The HTI Staff hasmore » been involved over the years in process development and has made significant improvements in the CMSL processing of coals. A 24 month program (extended to September 30, 1995) to study novel concepts, using a continuous bench scale Catalytic Multi-Stage unit (30kg coal/day), has been initiated since December, 1992. This program consists of ten bench-scale operations supported by Laboratory Studies, Modelling, Process Simulation and Economic Assessments. The Catalytic Multi-Stage Liquefaction is a continuation of the second generation yields using a low/high temperature approach. This paper covers work performed between October 1994- August 1995, especially results obtained from the microautoclave support activities and the bench-scale operations for runs CMSL-08 and CMSL-09, during which, coal and the plastic components for municipal solid wastes (MSW) such as high density polyethylene (HDPE)m, polypropylene (PP), polystyrene (PS), and polythylene terphthlate (PET) were coprocessed.« less

Processing of Janina coal at 600 atm. to gasoline and middle oil. Second progress report (in German)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hupfer, H.; Leonhardt

1944-03-13

The experiments described here were run in a 10-liter hydrogenation oven which was fitted with an outlet for desanding the reaction mixture to keep down the formation of caviar deposits in the oven. The experiments proceeded very well, and the Janina coal proved to be one that was very well suited to hydrogenation because of its relatively low carbon content. The coal gave high yields of products (0.35 kg/liter/hour), low losses to gases (18.6%), and low levels of asphalt formation. Although the fact needed further confirmation in full-scale operations, it seemed that the Janina coal did not require as highmore » a temperature from the preheater as did other coals in order to initiate the reaction (about 400/sup 0/C vs. about 425/sup 0/C). One of the disadvantages of the Janina coal was the fact that its rather large yield of liquid-phase gasoline had lower octane number than that from some other coals (Heinitz coal, for example - about 71 vs. 74). The gasoline contained 33% paraffins, 35% naphthenes, 23% aromatics, and 9% unsaturated compounds. The gasoline contained 11% phenol, whereas the middle oil contained 20.5% phenols. The aniline point of the various dephenolized fractions of gasoline varied from 18.2 to 36.0/sup 0/, whereas the aniline point of the various dephenolized fractions of middle oil varied from -24.5 to -14.0/sup 0/. The solidifying point of the heavy oil was 9/sup 0/C. 7 tables.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Byrer, C.W.; Layne, A.W.; Guthrie, H.D.

The U.S. Department of Energy (DOE), at its Morgantown Energy Technology Center, has been involved in natural gas research since the 1970`s. DOE has assessed the potential of gas in coals throughout the U.S. and promoted research and development for recovery and use of methane found in minable and unminable coalbeds. DOE efforts have focused on the use of coal mine methane for regional economic gas self-sufficiency, energy parks, self-help initiatives, and small-power generation. This paper focuses on DOE`s past and present efforts to more effectively and efficiently recover and use this valuable domestic energy source. The Climate Change Actionmore » Plan (CCAP) (1) lists a series of 50 voluntary initiatives designed to reduce greenhouse gas emissions, such as methane from mining operations, to their 1990 levels. Action No. 36 of the CCAP expands the DOE research, development, and demonstration (RD&D) efforts to broaden the range of cost-effective technologies and practices for recovering methane associated with coal mining operations. The major thrust of Action No. 36 is to reduce methane emissions associated with coal mining operations from target year 2000 levels by 1.5 MMT of carbon equivalent. Crosscutting activities in the DOE Natural Gas Program supply the utilization sectors will address RD&D to reduce methane emissions released from various mining operations, focusing on recovery and end use technology systems to effectively drain, capture, and utilize the emitted gas. Pilot projects with industry partners will develop and test the most effective methods and technology systems for economic recovery and utilization of coal mine gas emissions in regions where industry considers efforts to be presently non-economic. These existing RD&D programs focus on near-term gas recovery and gathering systems, gas upgrading, and power generation.« less

Coal to methanol feasiblity study: Beluga methanol project. Volume 4: Environmental

NASA Astrophysics Data System (ADS)

1981-09-01

The major environmental issues relevant to development of a coal gasification and methanol fuels production facility and related coal mining activities and transportation systems in the west Cook Inlet area, Alaska were assessed. An extensive review into existing information on the Beluga region of west Cook Inlet was conducted and updated with the findings of land resource projects. Specific field activities then were initiated to expand the environmental data base in areas relevant to this project where there was a paucity of information. Based on these findings the project was reviewed in detail to identify significant environmental issues and to outline the state and federal permit requirements to ensure that these element are an integral component of all subsequent project planning and management decisions.

Comprehensive assessment of toxic emissions from coal-fired power plants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brown, T D; Schmidt, C E; Radziwon, A S

1991-01-01

The Pittsburgh Energy Technology Center (PETC) of the US Department of Energy (DOE) has two current investigations, initiated before passage of the Clean Air Act Amendment (CAAA), that will determine the air toxic emissions from coal-fired electric utilities. DOE has contracted with Battelle Memorial Institute and Radian corporation to conduct studies focusing on the potential air toxics, both organic and inorganic, associated with different size fractions of fine particulate matter emitted from power plant stacks. Table 2 indicates the selected analytes to be investigated during these studies. PETC is also developing guidance on the monitoring of Hazardous Air Pollutants (HAPS)more » to be incorporated in the Environmental Monitoring plans for the demonstration projects in its Clean Coal Technology Program.« less

Wink Sink

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baumgardner, R.W. Jr.

1988-01-01

The Wink Sink formed on June 3, l980. Inferred precursor of the sinkhole was a solution cavity in the Permian Salado Formation formed either by natural dissolution or by water flow in an abandoned oil well. Correlation of well logs in the area indicates that the Salado Formation contains several dissolution zones. Dissolution in the middle of the Salado evaporite sequence may have resulted from ground-water flow along fractured anhydrite interbeds. The Wink Sink lies directly above the Permian Capitan reef on the margin of a natural salt dissolution trough. Other natural collapse features overlie the reef to the north.more » Hydraulic head of water in the reef is higher than the elevation of the Salado Formation but lower than the head in the Triassic Santa Rosa Sandstone, a near-surface freshwater aquifer. Fracture or cavernous permeability occurs above, within, and below the Salado Formation. Consequently, a brine-density flow may be operating: relatively fresh water moves upward through fractures under artesian pressure and dissolves salt; the denser brine moves downward under gravity flow. Alternatively, downward flow of water from freshwater aquifers above the salt may have caused dissolution. An oil well drilled into the Permian Yates Formation (with the aid of nitroglycerine) in 1928 was located within the sinkhole. The well initially produced about 80% saline water from the Permian Tansill Formation, which directly underlies the Salado. About 600 ft of casing was removed from the well when it was plugged and abandoned in 1964.« less

Insights into the dissolution and the three-dimensional structure of insensitive munitions formulations.

PubMed

Taylor, Susan; Ringelberg, David B; Dontsova, Katerina; Daghlian, Charles P; Walsh, Marianne E; Walsh, Michael R

2013-11-01

Two compounds, 2,4-dinitroanisole (DNAN) and 3-nitro-1,2,4-triazol-5-one (NTO) are the main ingredients in a suite of explosive formulations that are being, or soon will be, fielded at military training ranges. We aim to understand the dissolution characteristics of DNAN and NTO and three insensitive muntions (IM) formulations that contain them. This information is needed to accurately predict the environmental fate of IM constituents, some of which may be toxic to people and the environment. We used Raman spectroscopy to identify the different constituents in the IM formulations and micro computed tomography to image their three-dimensional structure. These are the first three-dimensional images of detonated explosive particles. For multi-component explosives the solubility of the individual constituents and the fraction of each constituent wetted by water controls the dissolution. We found that the order of magnitude differences in solubility amongst the constituents of these IM formulations quickly produced hole-riddled particles when these were exposed to water. Micro-computed tomography showed that particles resulting from field detonations were fractured, producing conduits by which water could access the interior of the particle. We think that micro-computed tomography can also be used to determine the initial composition of IM particles and to track how their compositions change as the particles dissolve. This information is critical to quantifying dissolution and developing physically based dissolution models. Published by Elsevier Ltd.

Numerical Modelling by FLAC on Coal Fires in North China

NASA Astrophysics Data System (ADS)

Gusat, D.; Drebenstedt, C.

2009-04-01

Coal fires occur in many countries all over the world (e.g. Australia, China, India, Indonesia, USA and Russia) in underground and on surface. In China the most coal fires occur especially in the North. Economical and environmental damages are the negative effects of the coal fires: coal fires induce open fractures and fissures within the seam and neighbouring rocks. So that these are the predominant pathways for oxygen flow and exhaust gases from a coal fire. All over northern China there are a large number of coal fires, which cause and estimated yearly coal loss of between 100 and 200 million tons ([1], [2], [3]). Spontaneous combustion is a very complicated process and is influenced by number of factors. The process is an exothermic reaction in which the heat generated is dissipated by conduction to the surrounding environment, by radiation, by convection to the ventilation flow, and in some cases by evaporation of moisture from the coal [4]. The coal fires are very serious in China, and the dangerous extent of spontaneous combustion is bad which occupies about 72.9% in mining coal seams. During coal mining in China, the coal fires of spontaneous combustion are quite severity. The dangerous of coal spontaneous combustion has been in 56% of state major coalmines [5]. The 2D and 3D-simulation models describing coal fire damages are strong tools to predict fractures and fissures, to estimate the risk of coal fire propagation into neighbouring seams, to test and evaluate coal fire fighting and prevention methods. The numerical simulations of the rock mechanical model were made with the software for geomechanical and geotechnical calculations, the programs FLAC and FLAC3D [6]. To fight again the coal fires, exist several fire fighting techniques. Water, slurries or liquefied nitrogen can be injected to cool down the coal or cut of air supply with the backfill and thereby extinct the fire. Air supply also can be cut of by covering the coal by soil or sealing of the coal mine with the backfill. A smaller fires can also be handled by taking out burning coal by bulldozing techniques described above are applicable to small fires, but they do not work well in extinction of large coal fires. References [1] http://www.coalfire.caf.dlr.de [2] Schalke, H.J.W.G.; Rosema, A.; Van Genderen, J.L. (1993): Environmental monitoring of coal fires in North China. Project Identification Mission Report. Report Remote Sensing Programme Board, Derft, the Netherlands. [3] Zhang, X.; Kroonenberg, S. B.; De Boer, C. B. (2004): Dating of coal fires in Xinjiang, north-west China. Terra Nova. Band 16, No 2, S. 68-74. DOI: 10.1111/j.1365-3121.2004.00532.x [4] Deng Jun, Hou Shuang, Li Huirong, e.t.c (2006): Oxidation Mechanism at Initial Stage of a Simulated Coal Molecule with -CH2O-[J]. Journal of Changchun University of Science and Technology, 29(2), P. 84-87. [5] Deng, Jun (2008): Presentation. Chinese Researches and Practical Experiences on Controlling Underground Coal Fires. The 2nd Australia-China Symposium on Science, Technology and Education. 15-18 October 2008, Courtyard Marriott, Surfers Paradise Beach, Gold Coast, Queensland, Australia. [6] Itasca (2003): FLAC, Fast Lagrangian Analysis of Continua. Itasca Consultants Group, Inc., Minneapolis.

Hydrometallurgical recycling of lithium-ion batteries by reductive leaching with sodium metabisulphite.

PubMed

Vieceli, Nathália; Nogueira, Carlos A; Guimarães, Carlos; Pereira, Manuel F C; Durão, Fernando O; Margarido, Fernanda

2018-01-01

The hydrometallurgical extraction of metals from spent lithium-ion batteries (LIBs) was investigated. LIBs were first dismantled and a fraction rich in the active material was obtained by physical separation, containing 95% of the initial electrode, 2% of the initial steel and 22% of plastic materials. Several reducers were tested to improve metals dissolution in the leaching step using sulphuric acid. Sodium metabisulphite led to the best results and was studied in more detail. The best concentration of Na 2 S 2 O 5 was 0.1 M. The metals dissolution increased with acid concentration, however, concentrations higher than 1.25 M are unnecessary. Best results were reached using a stirring speed of 400 min -1 . The metals leaching efficiency from the active material (Li, Mn, Ni, Co) increased with the temperature and was above 80% for temperatures higher than 60 °C. The dissolution of metals also rose with the increase in the liquid/solid ratio (L/S), however, extractions above 85% can be reached at L/S as lower as 4.5 L/kg, which is favourable for further purification and recovery operations. About 90% of metals extraction can be achieved after only 0.5 h of leaching. Sodium metabisulphite can be an alternative reducer to increase the leaching of Li, Mn, Co, and Ni from spent LIBs. Copyright © 2017 Elsevier Ltd. All rights reserved.

Degradable borate glass polyalkenoate cements.

PubMed

Shen, L; Coughlan, A; Towler, M; Hall, M

2014-04-01

Glass polyalkenoate cements (GPCs) containing aluminum-free borate glasses having the general composition Ag2O-Na2O-CaO-SrO-ZnO-TiO2-B2O3 were evaluated in this work. An initial screening study of sixteen compositions was used to identify regions of glass formation and cement compositions with promising rheological properties. The results of the screening study were used to develop four model borate glass compositions for further study. A second round of rheological experiments was used to identify a preferred GPC formulation for each model glass composition. The model borate glasses containing higher levels of TiO2 (7.5 mol %) tended to have longer working times and shorter setting times. Dissolution behavior of the four model GPC formulations was evaluated by measuring ion release profiles as a function of time. All four GPC formulations showed evidence of incongruent dissolution behavior when considering the relative release profiles of sodium and boron, although the exact dissolution profile of the glass was presumably obscured by the polymeric cement matrix. Compression testing was undertaken to evaluate cement strength over time during immersion in water. The cements containing the borate glass with 7.5 mol % TiO2 had the highest initial compressive strength, ranging between 20 and 30 MPa. No beneficial aging effect was observed-instead, the strength of all four model GPC formulations was found to degrade with time.

Thermal surface characteristics of coal fires 1 results of in-situ measurements

NASA Astrophysics Data System (ADS)

Zhang, Jianzhong; Kuenzer, Claudia

2007-12-01

Natural underground coal fires are fires in coal seams occurring subsurface. The fires are ignited through a process named spontaneous combustion, which occurs based on a natural reaction but is usually triggered through human interaction. Coal mining activities expose coal to the air. This leads to the exothermal oxidation of the carbon in the coal with the air's oxygen to CO 2 and - under certain circumstances - to spontaneous combustion. Coal fires occur in many countries world wide - however, currently the Chinese coal mining industry faces the biggest problems with coal fires. Coal fires destroy the valuable resource coal and furthermore lead to many environmental degradation phenomena such as the deterioration of surrounding vegetation, land subsidence and the emission of toxic gasses (CO, N 2O). They additionally contribute to the emission of green house relevant gasses such as CO 2 and CH 4 to the atmosphere. In this paper we present thermal characteristics of coal fires as measured in-situ during a field campaign to the Wuda coal fire area in south-central Inner Mongolia, China. Thermal characteristics include temperature anomaly measurements at the surface, spatial surface temperature profiles of fire areas and unaffected background areas, diurnal temperature profiles, and temperature measurements inside of coal fire induced cracks in the overlying bedrock. For all the measurements the effects of uneven solar heating through influences of slope and aspect are considered. Our findings show that coal fires result in strong or subtle thermal surface anomalies. Especially the latter can easily be influenced by heating of the surrounding background material through solar influences. Temperature variation of background rocks with different albedo, slope, aspect or vegetation cover can substantially influence the detectability of thermal anomalies. In the worst case coal fire related thermal anomalies can be completely masked by solar patterns during the daytime. Thus, night-time analysis is the most suitable for thermal anomaly mapping of underground coal fires, although this is not always feasible. The heat of underground coal fires only progresses very slowly through conduction in the rock material. Anomalies of coal fires completely covered by solid unfractured bedrock are very weak and were only measured during the night. The thermal pattern of underground coal fires manifested on the surface during the daytime is thus the pattern of cracks and vents, which occur due to the volume loss underground and which support radiation and convective energy transport of hot gasses. Inside coal fire temperatures can hardly be measured and can only be recorded if the glowing coal is exposed through a wider crack in the overlaying bedrock. Direct coal fire temperatures measured ranged between 233 °C and 854 °C. The results presented can substantially support the planning of thermal mapping campaigns, analyses of coal fire thermal anomalies in remotely sensed data, and can provide initial and boundary conditions for coal fire related numerical modeling. In a second paper named "Thermal Characteristics of Coal Fires 2: results of measurements on simulated coal fires" [ Zhang J., Kuenzer C., Tetzlaff A., Oettl D., Zhukov B., Wagner W., 2007. Thermal Characteristics of Coal Fires 2: Result of measurements on simulated coal fires. Accepted for publication at Journal of Applied Geophysics. doi:10.1016/j.jappgeo.2007.08.003] we report about thermal characteristics of simulated coal fires simulated under simplified conditions. The simulated set up allowed us to measure even more parameters under undisturbed conditions — especially inside fire temperatures. Furthermore we could demonstrate the differences between open surface coal fires and covered underground coal fires. Thermal signals of coal fires in near range thermal remotely sensed imagery from an observing tower and from an airplane are presented and discussed.

A study on the dissolution rates of K-Cr(VI)-jarosites: kinetic analysis and implications.

PubMed

Reyes, Iván A; Mireles, Ister; Patiño, Francisco; Pandiyan, Thangarasu; Flores, Mizraim U; Palacios, Elia G; Gutiérrez, Emmanuel J; Reyes, Martín

2016-01-01

The presence of natural and industrial jarosite type-compounds in the environment could have important implications in the mobility of potentially toxic elements such as lead, mercury, arsenic, chromium, among others. Understanding the dissolution reactions of jarosite-type compounds is notably important for an environmental assessment (for water and soil), since some of these elements could either return to the environment or work as temporary deposits of these species, thus would reduce their immediate environmental impact. This work reports the effects of temperature, pH, particle diameter and Cr(VI) content on the initial dissolution rates of K-Cr(VI)-jarosites (KFe3[(SO4)2 - X(CrO4)X](OH)6). Temperature (T) was the variable with the strongest effect, followed by pH in acid/alkaline medium (H3O(+)/OH(-)). It was found that the substitution of CrO4 (2-)in Y-site and the substitution of H3O(+) in M-site do not modify the dissolution rates. The model that describes the dissolution process is the unreacted core kinetic model, with the chemical reaction on the unreacted core surface. The dissolution in acid medium was congruent, while in alkaline media was incongruent. In both reaction media, there is a release of K(+), SO4 (2-) and CrO4 (2-) from the KFe3[(SO4)2 - X(CrO4)X](OH)6 structure, although the latter is rapidly absorbed by the solid residues of Fe(OH)3 in alkaline medium dissolutions. The dissolution of KFe3[(SO4)2 - X(CrO4)X](OH)6 exhibited good stability in a wide range of pH and T conditions corresponding to the calculated parameters of reaction order n, activation energy E A and dissolution rate constants for each kinetic stages of induction and progressive conversion. The kinetic analysis related to the reaction orders and calculated activation energies confirmed that extreme pH and T conditions are necessary to obtain considerably high dissolution rates. Extreme pH conditions (acidic or alkaline) cause the preferential release of K(+), SO4 (2-) and CrO4 (2-) from the KFe3[(SO4)2 - X(CrO4)X](OH)6 structure, although CrO4 (2-) is quickly adsorbed by Fe(OH)3 solid residues. The precipitation of phases such as KFe3[(SO4)2 - X(CrO4)X](OH)6, and the absorption of Cr(VI) after dissolution can play an important role as retention mechanisms of Cr(VI) in nature.

Adsorption of Crystal Violet Dye Using Zeolite A Synthesized From Coal Fly Ash

NASA Astrophysics Data System (ADS)

Jumaeri; Kusumastuti, E.; Santosa, S. J.; Sutarno

2017-02-01

Adsorption of Crystal Violet (CV) dye using zeolite A synthesized from coal fly ash (ZA) has been done. Effect of pH, contact time, and the initial concentration of dye adsorption was studied in this adsorption. Model experimental of adsorption isotherms and adsorption kinetics were also studied. The adsorption is done in a batch reactor at room temperature. A total of 0.01 g of zeolite A was added to the Erlenmeyer flask 50 mL containing 20 mL of the dye solution of Crystal Violet in a variety of conditions of pH, contact time and initial concentration. Furthermore, Erlenmeyer flask and its contents were shaken using an orbital shaker at a speed of 200 rpm. After a specified period of adsorption, the solution was centrifuged for 2 minutes so that the solids separated from the solution. The concentration of the dye after adsorption determined using Genesis-20 Spectrophotometer. The results showed that the Zeolite A synthesized from coal fly ash could be used as an effective adsorbent for Crystal Violet dye. The optimum adsorption occurs at pH 6, and contact time 45 minutes. At the initial concentration of 2 to 6 mg/L, adsorption is reduced from 79 to 62.8%. Crystal Violet dye adsorption in zeolite A fulfilled kinetic model of pseudo-order 2 and model of Freundlich adsorption isotherm.

HIGH PRESSURE COAL COMBUSTON KINETICS PROJECT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stefano Orsino

As part of the U.S. Department of Energy (DoE) initiative to improve the efficiency of coal-fired power plants and reduce the pollution generated by these facilities, DOE has funded the High-Pressure Coal Combustion Kinetics (HPCCK) Projects. A series of laboratory experiments were conducted on selected pulverized coals at elevated pressures with the specific goals to provide new data for pressurized coal combustion that will help extend to high pressure and validate models for burnout, pollutant formation, and generate samples of solid combustion products for analyses to fill crucial gaps in knowledge of char morphology and fly ash formation. Two seriesmore » of high-pressure coal combustion experiments were performed using SRI's pressurized radiant coal flow reactor. The first series of tests characterized the near burner flame zone (NBFZ). Three coals were tested, two high volatile bituminous (Pittsburgh No.8 and Illinois No.6), and one sub-bituminous (Powder River Basin), at pressures of 1, 2, and 3 MPa (10, 20, and 30 atm). The second series of experiments, which covered high-pressure burnout (HPBO) conditions, utilized a range of substantially longer combustion residence times to produce char burnout levels from 50% to 100%. The same three coals were tested at 1, 2, and 3 MPa, as well as at 0.2 MPa. Tests were also conducted on Pittsburgh No.8 coal in CO2 entrainment gas at 0.2, 1, and 2 MPa to begin establishing a database of experiments relevant to carbon sequestration techniques. The HPBO test series included use of an impactor-type particle sampler to measure the particle size distribution of fly ash produced under complete burnout conditions. The collected data have been interpreted with the help of CFD and detailed kinetics simulation to extend and validate devolatilization, char combustion and pollutant model at elevated pressure. A global NOX production sub-model has been proposed. The submodel reproduces the performance of the detailed chemical reaction mechanism for the NBFZ tests.« less

Application of MIKE SHE to study the impact of coal mining on river runoff in Gujiao mining area, Shanxi, China

PubMed Central

Ping, Jianhua; Yan, Shiyan; Gu, Pan; Wu, Zening; Hu, Caihong

2017-01-01

Coal mining is one of the core industries that contribute to the economic development of a country but deteriorate the environment. Being the primary source of energy, coal has become essential to meet the energy demand of a country. It is excavated by both opencast and underground mining methods and affects the environment, especially hydrological cycle, by discharging huge amounts of mine water. Natural hydrological processes have been well known to be vulnerable to human activities, especially large scale mining activities, which inevitably generate surface cracks and subsidence. It is therefore valuable to assess the impact of mining on river runoff for the sustainable development of regional economy. In this paper, the impact of coal mining on river runoff is assessed in one of the national key coal mining sites, Gujiao mining area, Shanxi Province, China. The characteristics of water cycle are described, the similarities and differences of runoff formation are analyzed in both coal mining and pre-mining periods. The integrated distributed hydrological model named MIKE SHE is employed to simulate and evaluate the influence of coal mining on river runoff. The study shows that mining one ton of raw coal leads to the reduction of river runoff by 2.87 m3 between 1981 and 2008, of which the surface runoff decreases by 0.24 m3 and the baseflow by 2.63 m3. The reduction degree of river runoff for mining one ton of raw coal shows an increasing trend over years. The current study also reveals that large scale coal mining initiates the formation of surface cracks and subsidence, which intercepts overland flow and enhances precipitation infiltration. Together with mine drainage, the natural hydrological processes and the stream flows have been altered and the river run off has been greatly reduced. PMID:29267313

The use of ethanol to remove sulfur from coal. Final report, September 1991--December 1992; Revision

DOE Office of Scientific and Technical Information (OSTI.GOV)

Savage, R.L.; Lazarov, L.K.; Prudich, M.E.

1994-03-10

The initial technical goal in the project was to develop a chemical method for the cost effective removal of both inorganic and organic sulfur from Ohio coals. Verifying and using a process of reacting ethanol vapors with coal under conditions disclosed in U.S. Patent 4,888,029, the immediate technical objectives were to convert a small scale laborative batch process to a larger scale continuous process which can serve as the basis for commercial development of the technology. This involved getting as much information as possible from small scale batch autoclave or fluid bed laboratory reactors for use in pilot plant studies.more » The laboratory data included material balances on the coal and sulfur, temperature and pressure ranges for the reaction, minimum reaction times at different conditions, the effectiveness of different activators such as oxygen and nitric oxide, the amount and nature of by-products such as sulfur dioxide, hydrogen sulfide and acetaldehyde, the effect of coal particle size on the speed and completeness of the reaction, and the effectiveness of the reaction on different Ohio coals. Because the laboratory experiments using the method disclosed in U.S. 4,888,029 were not successful, the objective for the project was changed to develop a new laboratory process to use ethanol to remove sulfur from coal. Using copper as a catalyst and as an H{sub 2}S scavenger, a new laboratory procedure to use ethanol to remove sulfur from coal has been developed at Ohio University and a patent application covering this process was filed in March, 1993. The process is based on the use of copper as a catalyst for the dehydrogenation of ethanol to produce nascent hydrogen to remove sulfur from the coal and the use of copper as a scavenger to capture the hydrogen sulfide formed from the sulfur removed from coal.« less

Application of MIKE SHE to study the impact of coal mining on river runoff in Gujiao mining area, Shanxi, China.

PubMed

Ping, Jianhua; Yan, Shiyan; Gu, Pan; Wu, Zening; Hu, Caihong

2017-01-01

Coal mining is one of the core industries that contribute to the economic development of a country but deteriorate the environment. Being the primary source of energy, coal has become essential to meet the energy demand of a country. It is excavated by both opencast and underground mining methods and affects the environment, especially hydrological cycle, by discharging huge amounts of mine water. Natural hydrological processes have been well known to be vulnerable to human activities, especially large scale mining activities, which inevitably generate surface cracks and subsidence. It is therefore valuable to assess the impact of mining on river runoff for the sustainable development of regional economy. In this paper, the impact of coal mining on river runoff is assessed in one of the national key coal mining sites, Gujiao mining area, Shanxi Province, China. The characteristics of water cycle are described, the similarities and differences of runoff formation are analyzed in both coal mining and pre-mining periods. The integrated distributed hydrological model named MIKE SHE is employed to simulate and evaluate the influence of coal mining on river runoff. The study shows that mining one ton of raw coal leads to the reduction of river runoff by 2.87 m3 between 1981 and 2008, of which the surface runoff decreases by 0.24 m3 and the baseflow by 2.63 m3. The reduction degree of river runoff for mining one ton of raw coal shows an increasing trend over years. The current study also reveals that large scale coal mining initiates the formation of surface cracks and subsidence, which intercepts overland flow and enhances precipitation infiltration. Together with mine drainage, the natural hydrological processes and the stream flows have been altered and the river run off has been greatly reduced.

Coal-bed methane discoveries in Powder River basin

DOE Office of Scientific and Technical Information (OSTI.GOV)

Matson, R.E.

1991-06-01

The Powder River basin of northeastern Wyoming and southeastern Montana contains the nation's largest supply of subbituminous coal. The coal beds have been mapped with surprising continuity, with thickness of individual beds exceeding 200 ft. The Paleocene Tongue River Member of the Fort Union Formation contains the bulk of the reserves. The coal near surface along the eastern part of the basin is subbituminous C, while in the deeper part and in the northwestern part of the basin the rank is subbituminous B or A. Commercial exploitation of methane in the Powder River was initiated by Wyatt Petroleum in themore » Recluse area north of Gillette in 1986. Early production was from sands occurring between major coal beds. Production directly from coal beds along the shallow eastern part of the Powder River basin was achieved by Betop Inc. in the Rawhide field a short distance north of Gillette in early 1989 from five wells. Fifteen additional wells were drilled and completed in the field in late 1990. Other shallow coal-bed methane production has been achieved from the same thick Wyodak coalbed nearby by Martins and Peck Operating, Wasatch Energy, and DCD Inc. Numerous deeper tests have been drilled and tested by various companies including Coastal Oil and Gas, Materi Exploration, Cenex, Gilmore Oil and Gas, and Betop Inc., none of which has attained commercial success. Recent exploration in the northwestern part of the basin has resulted in two apparent discoveries.« less

Effects of Igneous Intrusion on Microporosity and Gas Adsorption Capacity of Coals in the Haizi Mine, China

PubMed Central

2014-01-01

This paper describes the effects of igneous intrusions on pore structure and adsorption capacity of the Permian coals in the Huaibei Coalfield, China. Twelve coal samples were obtained at different distances from a ~120 m extremely thick sill. Comparisons were made between unaltered and heat-affected coals using geochemical data, pore-fracture characteristics, and adsorption properties. Thermal alteration occurs down to ~1.3 × sill thickness. Approaching the sill, the vitrinite reflectance (R o) increased from 2.30% to 2.78%, forming devolatilization vacuoles and a fine mosaic texture. Volatile matter (VM) decreased from 17.6% to 10.0% and the moisture decreased from 3.0% to 1.6%. With decreasing distance to the sill, the micropore volumes initially increased from 0.0054 cm3/g to a maximum of 0.0146 cm3/g and then decreased to 0.0079 cm3/g. The results show that the thermal evolution of the sill obviously changed the coal geochemistry and increased the micropore volume and adsorption capacity of heat-affected coal (60–160 m from the sill) compared with the unaltered coals. The trap effect of the sill prevented the high-pressure gas from being released, forming gas pocket. Mining activities near the sill created a low pressure zone leading to the rapid accumulation of methane and gas outbursts in the Haizi Mine. PMID:24723841

Chemicl-looping combustion of coal with metal oxide oxygen carriers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Siriwardane, R.; Tian, H.; Richards, G.

2009-01-01

The combustion and reoxidation properties of direct coal chemical-looping combustion (CLC) over CuO, Fe2O3, Co3O4, NiO, and Mn2O3 were investigated using thermogravimetric analysis (TGA) and bench-scale fixed-bed flow reactor studies. When coal is heated in either nitrogen or carbon dioxide (CO2), 50% of weight loss was observed because of partial pyrolysis, consistent with the proximate analysis. Among various metal oxides evaluated, CuO showed the best reaction properties: CuO can initiate the reduction reaction as low as 500 °C and complete the full combustion at 700 °C. In addition, the reduced copper can be fully reoxidized by air at 700 °C.more » The combustion products formed during the CLC reaction of the coal/metal oxide mixture are CO2 and water, while no carbon monoxide was observed. Multicycle TGA tests and bench-scale fixed-bed flow reactor tests strongly supported the feasibility of CLC of coal by using CuO as an oxygen carrier. Scanning electron microscopy (SEM) images of solid reaction products indicated some changes in the surface morphology of a CuO-coal sample after reduction/oxidation reactions at 800 °C. However, significant surface sintering was not observed. The interactions of fly ash with metal oxides were investigated by X-ray diffraction and thermodynamic analysis. Overall, the results indicated that it is feasible to develop CLC with coal by metal oxides as oxygen carriers.« less

Technology for advanced liquefaction processes: Coal/waste coprocessing studies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cugini, A.V.; Rothenberger, K.S.; Ciocco, M.V.

1995-12-31

The efforts in this project are directed toward three areas: (1) novel catalyst (supported and unsupported) research and development, (2) study and optimization of major operating parameters (specifically pressure), and (3) coal/waste coprocessing. The novel catalyst research and development activity has involved testing supported catalysts, dispersed catalysts, and use of catalyst testing units to investigate the effects of operating parameters (the second area) with both supported and unsupported catalysts. Several supported catalysts were tested in a simulated first stage coal liquefaction application at 404{degrees}C during this performance period. A Ni-Mo hydrous titanate catalyst on an Amocat support prepared by Sandiamore » National laboratories was tested. Other baseline experiments using AO-60 and Amocat, both Ni-Mo/Al{sub 2}O{sub 3} supported catalysts, were also made. These experiments were short duration (approximately 12 days) and monitored the initial activity of the catalysts. The results of these tests indicate that the Sandia catalyst performed as well as the commercially prepared catalysts. Future tests are planned with other Sandia preparations. The dispersed catalysts tested include sulfated iron oxide, Bayferrox iron oxide (iron oxide from Miles, Inc.), and Bailey iron oxide (micronized iron oxide from Bailey, Inc.). The effects of space velocity, temperature, and solvent-to-coal ratio on coal liquefaction activity with the dispersed catalysts were investigated. A comparison of the coal liquefaction activity of these catalysts relative to iron catalysts tested earlier, including FeOOH-impregnated coal, was made. These studies are discussed.« less

Geochemical Proxies for Enhanced Process Control of Underground Coal Gasification

NASA Astrophysics Data System (ADS)

Kronimus, A.; Koenen, M.; David, P.; Veld, H.; van Dijk, A.; van Bergen, F.

2009-04-01

Underground coal gasification (UCG) represents a strategy targeting at syngas production for fuel or power generation from in-situ coal seams. It is a promising technique for exploiting coal deposits as an energy source at locations not allowing conventional mining under economic conditions. Although the underlying concept has already been suggested in 1868 and has been later on implemented in a number of field trials and even at a commercial scale, UCG is still facing technological barriers, impeding its widespread application. Field UCG operations rely on injection wells enabling the ignition of the target seam and the supply with oxidants (air, O2) inducing combustion (oxidative conditions). The combustion process delivers the enthalpy required for endothermic hydrogen production under reduction prone conditions in some distance to the injection point. The produced hydrogen - usually accompanied by organic and inorganic carbon species, e.g. CH4, CO, and CO2 - can then be retrieved through a production well. In contrast to gasification of mined coal in furnaces, it is difficult to measure the combustion temperature directly during UCG operations. It is already known that geochemical parameters such as the relative production gas composition as well as its stable isotope signature are related to the combustion temperature and, consequently, can be used as temperature proxies. However, so far the general applicability of such relations has not been proven. In order to get corresponding insights with respect to coals of significantly different rank and origin, four powdered coal samples covering maturities ranging from Ro= 0.43% (lignite) to Ro= 3.39% (anthracite) have been gasified in laboratory experiments. The combustion temperature has been varied between 350 and 900 ˚ C, respectively. During gasification, the generated gas has been captured in a cryo-trap, dried and the carbon containing gas components have been catalytically oxidized to CO2. Thereafter, the generated CO2 has been analyzed with respect to its stable carbon isotope composition by mass spectrometry. All samples exhibited a similar trend: The ^13C signatures of initially produced CO2 revealed to be relatively light and linearly increasing with temperature until approaching the bulk stable carbon isotope composition of the coal at a certain temperature, where the isotope signature kept virtually constant during further temperature increase. The temperature introducing the range of constant isotope compositions of the produced gas increased with coal rank. Additionally, all coal samples were treated by Rock Eval pyrolysis up to 550 ˚ C in order to investigate temperature dependent generation of CO and CO2. The results exhibited a linear decrease of the CO2/CO ratio at increasing temperature. Both experimental approaches demonstrated dependencies between the qualitative and the isotope composition of the generated syngas on the one hand and the applied combustion temperature on the other hand and, consequently, the principal applicability of the considered geochemical parameters as temperature proxies for coals of significantly different rank and origin. Although the investigated samples revealed similar trends, the absolute characteristics of the correlation functions (e.g. linear gradients) between geochemical parameters and combustion temperatures differed on an individual sample base, implying a significant additional dependence of the considered geochemical parameters on the coal composition. As a consequence, corresponding experimental approaches are currently continued and refined by involving multi component compound specific isotope analysis, high temperature Rock Eval pyrolysis as well as an enforced consideration of initial coal and oxidant compositions.

Recovery of fissile materials from nuclear wastes

DOEpatents

Forsberg, Charles W.

1999-01-01

A process for recovering fissile materials such as uranium, and plutonium, and rare earth elements, from complex waste feed material, and converting the remaining wastes into a waste glass suitable for storage or disposal. The waste feed is mixed with a dissolution glass formed of lead oxide and boron oxide resulting in oxidation, dehalogenation, and dissolution of metal oxides. Carbon is added to remove lead oxide, and a boron oxide fusion melt is produced. The fusion melt is essentially devoid of organic materials and halogens, and is easily and rapidly dissolved in nitric acid. After dissolution, uranium, plutonium and rare earth elements are separated from the acid and recovered by processes such as PUREX or ion exchange. The remaining acid waste stream is vitrified to produce a waste glass suitable for storage or disposal. Potential waste feed materials include plutonium scrap and residue, miscellaneous spent nuclear fuel, and uranium fissile wastes. The initial feed materials may contain mixtures of metals, ceramics, amorphous solids, halides, organic material and other carbon-containing material.

Environmental Degradation of Materials: Surface Chemistry Related to Stress Corrosion Cracking

NASA Technical Reports Server (NTRS)

Schwarz, J. A.

1985-01-01

Parallel experiments have been performed in order to develop a comprehensive model for stress cracking (SCC) in structural materials. The central objective is to determine the relationship between the activity and selectivity of the microstructure of structural materials to their dissolution kinetics and experimentally measured SCC kinetics. Zinc was chosen as a prototype metal system. The SCC behavior of two oriented single-crystal disks of zinc in a chromic oxide/sodium sulfate solution (Palmerton solution) were determined. It was found that: (1) the dissolution rate is strongly (hkil)-dependent and proportional to the exposure time in the aggressive environment; and (2) a specific slip system is selectively active to dissolution under applied stress and this slip line controls crack initiation and propagation. As a precursor to potential microgrvity experiments, electrophoretic mobility measurements of zinc particles were obtained in solutions of sodium sulfate (0.0033 M) with concentrations of dissolved oxygen from 2 to 8 ppm. The equilibrium distribution of exposed oriented planes as well as their correlation will determine the particle mobility.

Solid dispersion of efavirenz in PVP K-30 by conventional solvent and kneading methods.

PubMed

Alves, Lariza Darlene Santos; de La Roca Soares, Mônica Felts; de Albuquerque, Camila Tavares; da Silva, Elica Rodrigues; Vieira, Alexandre Couto Carneiro; Fontes, Danilo Augusto Ferreira; Figueirêdo, Camila Bezerra Melo; Soares Sobrinho, José Lamartine; Rolim Neto, Pedro José

2014-04-15

Efavirenz (EFV) used as a part of the treatment of first choice in antiretroviral therapy for AIDS has low aqueous solubility and presents problems of absorption. We thus initially present a phase solubility diagram with carriers of different classes. With a view to obtaining a solid dispersion (SD) with suitable consistency to that of a solid formulation, we chose to use PVP K-30, since polymers present some of the best results. The kneading (KN) and solvent evaporation (EV) methods were thus used at different rates. These were characterized by the way of DSC, FT-IR, SEM, DR-X and dissolution. SD EV proved unsatisfactory, resulting in a decreased dissolution rate, despite the amorphous state of the samples, while the SD KN 4:1 (EFV:polymer) and physical mixtures (PM) had a higher rate of dissolution. SD KN and PM 4:1 were also evaluated for stability after storage, with benefits being observed in relation to EFV. Copyright © 2014. Published by Elsevier Ltd.

Design and performance of limestone drains to increase pH and remove metals from acidic mine drainage, Chapter 2

USGS Publications Warehouse

Cravotta,, Charles A.; Watzlaf, George R.

2002-01-01

Data on the construction characteristics and the composition of influent and effluent at 13 underground, limestone-filled drains in Pennsylvania and Maryland are reported to evaluate the design and performance of limestone drains for the attenuation of acidity and dissolved metals in acidic mine drainage. On the basis of the initial mass of limestone, dimensions of the drains, and average flow rates, the initial porosity and average detention time for each drain were computed. Calculated porosity ranged from 0.12 to 0.50 with corresponding detention times at average flow from 1.3 to 33 h. The effectiveness of treatment was dependent on influent chemistry, detention time, and limestone purity. At two sites where influent contained elevated dissolved Al (>5 mg/liter), drain performance declined rapidly; elsewhere the drains consistently produced near-neutral effluent, even when influent contained small concentrations of dissolved Fe^+ (<5 mg/liter). Rates of limestone dissolution computed on the basis of average long-term Ca ion flux normalized by initial mass and purity of limestone at each of the drains ranged from 0.008 to 0.079 year-1. Data for alkalinity concentration and flux during 11-day closed-container tests using an initial mass of 4kg crushed limestone and a solution volume of 2.3 liter yielded dissolution rate constants that were comparable to these long-term field rates. An analytical method is proposed using closed-container test data to evaluate long-term performance (longevity) or to estimate the mass of limestone needed for a limestone treatment. This method condisers flow rate, influent alkalinity, steady-state alkalinity of effluent, and desired effluent alkalinity or detention time at a future time(s) and aplies first-order rate laws for limestone dissolution (continuous) and production of alkalinity (bounded).

Investigation of drug loading and in vitro release mechanisms of insulin-lauryl sulfate complex loaded PLGA nanoparticles.

PubMed

Shi, K; Cui, F; Yamamoto, H; Kawashima, Y

2008-12-01

Insulin, a water soluble peptide hormone, was hydrophobically ion-paired with sodium lauryl sulfate (SDS) at the stoichiometric molar ratio of 6:1. The obtained insulin-SDS complex precipitation was subsequently formulated in biodegradable poly (D,L-lactic-co-glycolic acid) (PLGA) nanoparticles by a modified spontaneous emulsion solvent diffusion method. Compared with a conventional method for free insulin encapsulation, direct dissolution of SDS-paired insulin in the non-aqueous organic phase led to an increase in drug recovery from 42.5% to 89.6%. The more hydrophobic complex contributes to the improved affinity of insulin to the polymer matrix, resulting in a higher drug content in the nanoparticles. The drug loading was investigated by determining initial burst release at the first 30 min. The results showed that 64.8% of recovered drug were preferentially surface bound on complex loaded nanoparticles. The in vitro drug release was characterized by an initial burst and subsequent delayed release in dissolution media of deionized water and phosphate buffer saline (PBS). Compared with that in PBS, nanoparticles in deionized water medium presented very low initial burst release (15% vs. 65%) and incomplete cumulative release (25% vs. 90%) of the drug. In addition, dialysis experiments were performed to clarify the form of the released insulin in the dissolution media. The results suggested that the ion-pair complex was sensitive to ionic strength, insulin was released from the particular matrix as complex form and subsequently suffered dissociation from SDS in buffer saline. Moreover, the in vivo bioactivity of the SDS-paired insulin and nanoparticulate formulations were evaluated in mice by estimation of their blood sugar levels. The results showed that the bioactivity of insulin was unaltered after the ion-pairing process.

Global Development of Commercial Underground Coal Gasification

NASA Astrophysics Data System (ADS)

Blinderman, M. S.

2017-07-01

Global development of Underground Coal Gasification (UCG) is considered here in light of latest trends of energy markets and environmental regulations in the countries that have been traditional proponents of UCG. The latest period of UCG development triggered by initial success of the Chinchilla UCG project (1997-2006) has been characterized by preponderance of privately and share-market funded developments. The deceleration of UCG commercialization has been in part caused by recent significant decrease of world oil, gas and coal prices. Another substantial factor was lack of necessary regulations governing extraction and conversion of coal by UCG method in the jurisdictions where the UCG projects were proposed and developed. Along with these objective causes there seem to have been more subjective and technical reasons for a slowdown or cancelation of several significant UCG projects, including low efficiency, poor environmental performance, and inability to demonstrate technology at a sufficient scale and/or at a competitive cost. Latest proposals for UCG projects are briefly reviewed.

Combustion properties, water absorption and grindability of raw/torrefied biomass pellets and Silantek coal

NASA Astrophysics Data System (ADS)

Matali, Sharmeela; Rahman, Norazah Abdul; Idris, Siti Shawaliah; Yaacob, Nurhafizah

2017-12-01

Torrefaction, also known as mild pyrolysis, is proven to convert raw biomass into a value-added energy commodity particularly for application in combustion and co-firing systems with improved storage and handling properties. This paper aims to compare the characteristics of Malaysian bituminous coal i.e. Silantek coal with raw and torrefied biomass pellet originated from oil palm frond and fast growing tree species, Leucaena Leucocephala. Biomass samples were initially torrefied at 300 °C for 60 minutes. Resulting torrefied biomass pellets were analysed using a number of standard fuel characterisation analyses i.e. elemental analysis, proximate analysis and calorific content (high heating values) experiments. Investigations on combustion characteristics via dynamic thermogravimetric analysis (TGA), grindability and moisture uptake tests were also performed on the torrefied biomass pellets. Better quality bio-chars were produced as compared to its raw forms and with optimal process conditions, torrefaction may potentially produces a solid fuel with combustion reactivity and porosity equivalent to raw biomass while having compatible energy density and grindability to coal.

Effect of Ni-Co Ternary Molten Salt Catalysts on Coal Catalytic Pyrolysis Process

NASA Astrophysics Data System (ADS)

Cui, Xin; Qi, Cong; Li, Liang; Li, Yimin; Li, Song

2017-08-01

In order to facilitate efficient and clean utilization of coal, a series of Ni-Co ternary molten salt crystals are explored and the catalytic pyrolysis mechanism of Datong coal is investigated. The reaction mechanisms of coal are achieved by thermal gravimetric analyzer (TGA), and a reactive kinetic model is constructed. The microcosmic structure and macerals are observed by scanning electron microscope (SEM). The catalytic effects of ternary molten salt crystals at different stages of pyrolysis are analyzed. The experimental results show that Ni-Co ternary molten salt catalysts have the capability to bring down activation energy required by pyrolytic reactions at its initial phase. Also, the catalysts exert a preferable catalytic action on macromolecular structure decomposition and free radical polycondensation reactions. Furthermore, the high-temperature condensation polymerization is driven to decompose further with a faster reaction rate by the additions of Ni-Co ternary molten salt crystal catalysts. According to pyrolysis kinetic research, the addition of catalysts can effectively decrease the activation energy needed in each phase of pyrolysis reaction.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Spencer, D.F.

This analysis evaluates the incentives necessary to introduce commercial scale Advanced Clean Coal Technologies, specifically Integrated Coal Gasification Combined Cycle (ICGCC) and Pressurized Fluidized Bed Combustion (PFBC) powerplants. The incentives required to support the initial introduction of these systems are based on competitive busbar electricity costs with natural gas fired combined cycle powerplants, in baseload service. A federal government price guarantee program for up to 10 Advanced Clean Coal Technology powerplants, 5 each ICGCC and PFBC systems is recommended in order to establish the commercial viability of these systems by 2010. By utilizing a decreasing incentives approach as the technologiesmore » mature (plants 1--5 of each type), and considering the additional federal government benefits of these plants versus natural gas fired combined cycle powerplants, federal government net financial exposure is minimized. Annual net incentive outlays of approximately 150 million annually over a 20 year period could be necessary. Based on increased demand for Advanced Clean Coal Technologies beyond 2010, the federal government would be revenue neutral within 10 years of the incentives program completion.« less

Chapter 1: The Appalachian regional reforestation initiative

Treesearch

Patrick Angel; Vic Davis; Jim Burger; Don Graves; Carl Zipper

2017-01-01

The Appalachian Regional Reforestation Initiative (ARRI) is a cooperative effort by the States of the Appalachian region with the U.S. Department of the Interior's Office of Surface Mining Reclamation and Enforcement (OSMRE) to encourage restoration of high-quality forests on reclaimed coal mines in the eastern United States. The goals of ARRI are to communicate...

30 CFR 75.1320 - Multiple-shot blasting.

Code of Federal Regulations, 2013 CFR

2013-07-01

... in a round shall be initiated in sequence from the opener hole or holes. (e) Arrangement of detonator... blasting coal off the solid— (i) Each shot in the round shall be initiated in sequence from the opener hole or holes; and (ii) After the first shot or shots, the interval between the designated delay periods...

30 CFR 75.1320 - Multiple-shot blasting.

Code of Federal Regulations, 2014 CFR

2014-07-01

... in a round shall be initiated in sequence from the opener hole or holes. (e) Arrangement of detonator... blasting coal off the solid— (i) Each shot in the round shall be initiated in sequence from the opener hole or holes; and (ii) After the first shot or shots, the interval between the designated delay periods...

30 CFR 75.1320 - Multiple-shot blasting.

Code of Federal Regulations, 2012 CFR

2012-07-01

... in a round shall be initiated in sequence from the opener hole or holes. (e) Arrangement of detonator... blasting coal off the solid— (i) Each shot in the round shall be initiated in sequence from the opener hole or holes; and (ii) After the first shot or shots, the interval between the designated delay periods...

30 CFR 75.1320 - Multiple-shot blasting.

Code of Federal Regulations, 2011 CFR

2011-07-01

... in a round shall be initiated in sequence from the opener hole or holes. (e) Arrangement of detonator... blasting coal off the solid— (i) Each shot in the round shall be initiated in sequence from the opener hole or holes; and (ii) After the first shot or shots, the interval between the designated delay periods...

30 CFR 75.1320 - Multiple-shot blasting.

Code of Federal Regulations, 2010 CFR

2010-07-01

... in a round shall be initiated in sequence from the opener hole or holes. (e) Arrangement of detonator... blasting coal off the solid— (i) Each shot in the round shall be initiated in sequence from the opener hole or holes; and (ii) After the first shot or shots, the interval between the designated delay periods...

Dissolution of a Tetrachloroethene (PCE) pool in an Anaerobic Sand Tank Aquifer System: Bioenhancement, Ecology, and Hydrodynamics

NASA Astrophysics Data System (ADS)

Klemm, Sara; Becker, Jennifer; Seagren, Eric

2017-04-01

Dehalorespiring bacteria that reductively dechlorinate and grow on chlorinated ethenes in the aqueous phase can also achieve treatment of dense nonaqueous phase liquid (DNAPL) contaminants in the subsurface via bioenhanced dissolution, i.e., enhanced mass transfer from the DNAPL to the aqueous phase. Theoretical and experimental analyses predict that a number of interrelated physicochemical processes (e.g., advection and dispersion) and biological factors (e.g., biokinetics and competition) may influence the degree of bioenhancement. This research focused on understanding the interrelated roles that hydrodynamics and ecological interactions among dehalorespiring populations play in determining the distribution of dehalorespiring populations and the impact on bioenhanced dissolution and detoxification. The hypotheses driving this research are that: (1) ecological interactions between different dehalorespiring strains can significantly impact the dissolution rate bioenhancement and extent of dechlorination; and (2) hydrodynamics near the DNAPL pool will affect the outcome of ecological interactions and the potential for bioenhancement and detoxification. These hypotheses were evaluated via a multi-objective modeling and experimental framework focused on quantifying the impact of microbial interactions and hydrodynamics on the dissolution rate bioenhancement and plume detoxification using a model co-culture of Desulfuromonas michiganensis BB1 and Dehalococcoides mccartyi 195. The experiments were performed in a saturated intermediate-scale flow cell (1.2 m), with flow parallel to a tetrachloroethene (PCE) pool. Bioenhancement of PCE dissolution by the two dehalorespirers was evaluated using a steady-state mass balance, and initially resulted in a two- to three-fold increase in the dissolution rate, with cis-dichloroethene (cDCE) as the primary dechlorination product. Quantitative analysis of microbial population distribution and abundance using a 16S rRNA gene-based qPCR approach indicated that Dsm. michiganensis BB1 was the dominant population in the effluent. This was expected based on our previous work characterizing the PCE utilization kinetics of the two populations, and suggests that Dsm. michiganensis BB1 was the dominant population in the aquifer system and controlled PCE dissolution and its bioenhancement. This conclusion is consistent with our numerical modeling predictions for the same conditions, which suggested Dhc. mccartyi 195 had little effect on dissolution and dehalorespiration, but aided detoxification by growing on the cDCE produced by Dsm. michiganensis BB1. Subsequently, the PCE dissolution enhancement increased to six- to seven-fold relative to the abiotic dissolution rate. Quantitative analysis of population distribution and abundance in the porous media and nonreactive tracer studies suggested that microbial growth-induced bioclogging, coupled with inhibition of microbial activity near the DNAPL, resulted in increased flow immediately adjacent to the DNAPL-aqueous interface. The increased flow rate past the DNAPL could explain the observed increase in the PCE dissolution rate and is consistent with our numerical modeling of the system. The research described here is part of a larger project working to improve the fundamental understanding of the impact of hydrodynamics and ecological interactions on DNAPL dissolution rate bioenhancement and plume detoxification. These biotic data build on the baseline abiotic experiments reported in another abstract submitted to Session HS8.1.6.

Coal liquefaction process

DOEpatents

Maa, Peter S.

1978-01-01

A process for liquefying a particulate coal feed to produce useful petroleum-like liquid products which comprises contacting; in a series of two or more coal liquefaction zones, or stages, graded with respect to temperature, an admixture of a polar compound; or compounds, a hydrogen donor solvent and particulate coal, the total effluent being passed in each instance from a low temperature zone, or stage to the next succeeding higher temperature zone, or stage, of the series. The temperature within the initial zone, or stage, of the series is maintained about 70.degree. F and 750.degree. F and the temperature within the final zone, or stage, is maintained between about 750.degree. F and 950.degree. F. The residence time within the first zone, or stage, ranges, generally, from about 20 to about 150 minutes and residence time within each of the remaining zones, or stages, of the series ranges, generally, from about 10 minutes to about 70 minutes. Further steps of the process include: separating the product from the liquefaction zone into fractions inclusive of a liquid solvent fraction; hydrotreating said liquid solvent fraction in a hydrogenation zone; and recycling the hydrogenated liquid solvent mixture to said coal liquefaction zones.

Poromechanical response of naturally fractured sorbing media

NASA Astrophysics Data System (ADS)

Kumar, Hemant

The injection of CO2 in coal seams has been utilized for enhanced gas recovery and potential CO2 sequestration in unmineable coal seams. It is advantageous because as it enhances the production and significant volumes of CO2 may be stored simultaneously. The key issues for enhanced gas recovery and geologic sequestration of CO2 include (1) Injectivity prediction: The chemical and physical processes initiated by the injection of CO2 in the coal seam leads to permeability/porosity changes (2) Up scaling: Development of full scale coupled reservoir model which may predict the enhanced production, associated permeability changes and quantity of sequestered CO2. (3) Reservoir Stimulation: The coalbeds are often fractured and proppants are placed into the fractures to prevent the permeability reduction but the permeability evolution in such cases is poorly understood. These issues are largely governed by dynamic coupling of adsorption, fluid exchange, transport, water content, stress regime, fracture geometry and physiomechanical changes in coals which are triggered by CO 2 injection. The understanding of complex interactions in coal has been investigated through laboratory experiments and full reservoir scale models are developed to answer key issues. (Abstract shortened by ProQuest.).

The recovery of zinc from hot galvanizing slag in an anion-exchange membrane electrolysis reactor.

PubMed

Ren, Xiulian; Wei, Qifeng; Hu, Surong; Wei, Sijie

2010-09-15

This paper reports the optimization of the process parameters for recovery of zinc from hot galvanizing slag in an anion-exchange membrane electrolysis reactor. The experiments were carried out in an ammoniacal ammonium chloride system. The influence of composition of electrolytes, pH, stirring rate, current density and temperature, on cathodic current efficiency, specific power consumption and anodic dissolution of Zn were investigated. The results indicate that the cathode current efficiency increases and the hydrogen evolution decreased with increasing the cathode current density. The partial current for electrodeposition of Zn has liner relationship with omega(1/2) (omega: rotation rate). The highest current efficiency for dissolving zinc was obtained when NH(4)Cl concentration was 53.46 g L(-1) and the anodic dissolution of zinc was determined by mass transfer rate at stirring rate 0-300 r min(-1). Increase in temperature benefits to improve CE and dissolution of Zn, and reduce cell voltage. Initial pH of electrolytes plays an important role in the deposition and anodic dissolution of Zn. The results of single factor experiment show that about 50% energy consumption was saved for electrodeposition of Zn in the anion-exchange membrane electrolysis reactor. Copyright 2010 Elsevier B.V. All rights reserved.

Dispersion in Fractures with Ramified Dissolution Patterns

NASA Astrophysics Data System (ADS)

Xu, Le; Marks, Benjy; Toussaint, Renaud; Flekkøy, Eirik G.; Måløy, Knut J.

2018-04-01

The injection of a reactive fluid into an open fracture may modify the fracture surface locally and create a ramified structure around the injection point. This structure will have a significant impact on the dispersion of the injected fluid due to increased permeability, which will introduce large velocity fluctuations into the fluid. Here, we have injected a fluorescent tracer fluid into a transparent artificial fracture with such a ramified structure. The transparency of the model makes it possible to follow the detailed dispersion of the tracer concentration. The experiments have been compared to two dimensional (2D) computer simulations which include both convective motion and molecular diffusion. A comparison was also performed between the dispersion from an initially ramified dissolution structure and the dispersion from an initially circular region. A significant difference was seen both at small and large length scales. At large length scales, the persistence of the anisotropy of the concentration distribution far from the ramified structure is discussed with reference to some theoretical considerations and comparison with simulations.

Nitrogen mineralization from sludge in an alkaline, saline coal gasification ash environment.

PubMed

Mbakwe, Ikenna; De Jager, Pieter C; Annandale, John G; Matema, Taurai

2013-01-01

Rehabilitating coal gasification ash dumps by amendment with waste-activated sludge has been shown to improve the physical and chemical properties of ash and to facilitate the establishment of vegetation. However, mineralization of organic N from sludge in such an alkaline and saline medium and the effect that ash weathering has on the process are poorly understood and need to be ascertained to make decisions regarding the suitability of this rehabilitation option. This study investigated the rate and pattern of N mineralization from sludge in a coal gasification ash medium to determine the prevalent inorganic N form in the system and assess the effect of ash weathering on N mineralization. An incubation experiment was performed in which fresh ash, weathered ash, and soil were amended with the equivalent of 90 Mg ha sludge, and N mineralization was evaluated over 63 d. More N (24%) was mineralized in fresh ash than in weathered ash and soil, both of which mineralized 15% of the initial organic N in sludge. More nitrification occurred in soil, and most of the N mineralized in ash was in the form of ammonium, indicating an inhibition of nitrifying organisms in the ash medium and suggesting that, at least initially, plants used for rehabilitation of coal gasification ash dumps will take up N mostly as ammonium. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Catalytic oxidation of gaseous reduced sulfur compounds using coal fly ash.

PubMed

Kastner, James R; Das, K C; Melear, Nathan D

2002-11-11

Activated carbon has been shown to oxidize reduced sulfur compounds, but in many cases it is too costly for large-scale environmental remediation applications. Alternatively, we theorized that coal fly ash, given its high metal content and the presence of carbon could act as an inexpensive catalytic oxidizer of reduced sulfur compounds for "odor" removal. Initial results indicate that coal fly ash can catalyze the oxidization of H(2)S and ethanethiol, but not dimethyl sulfide (DMS) and dimethyl disulfide (DMDS) at room temperature. In batch reactor systems, initial concentrations of 100-500 ppmv H(2)S or ethanethiol were reduced to 0-2 ppmv within 1-2 and 6-8 min, respectively. This was contrary to control systems without ash in which concentrations remained constant. Diethyl disulfide was formed from ethanethiol substantiating the claim that catalytic oxidation occurred. The presence of water increased the rate of adsorption/reaction of both H(2)S and ethanethiol for the room temperature reactions (23-25 degrees C). Additionally, in a continuous flow packed bed reactor, a gaseous stream containing an inlet H(2)S concentration of 400-500 ppmv was reduced to 200 ppmv at a 4.6s residence time. The removal efficiency remained at 50% for approximately 4.6h or 3500 reactor volumes. These results demonstrate the potential of using coal fly ash in reactors for removal of H(2)S and other reduced sulfur compounds.

Dissolution of bedded rock salt: A seismic profile across the active eastern margin of the Hutchinson Salt Member, central Kansas

USGS Publications Warehouse

Anderson, N.L.; Hopkins, J.; Martinez, A.; Knapp, R.W.; Macfarlane, P.A.; Watney, W.L.; Black, R.

1994-01-01

Since late Tertiary, bedded rock salt of the Permian Hutchinson Salt Member has been dissolved more-or-less continuously along its active eastern margin in central Kansas as a result of sustained contact with unconfined, undersaturated groundwater. The associated westward migration of the eastern margin has resulted in surface subsidence and the contemporaneous sedimentation of predominantly valley-filling Quarternary alluvium. In places, these alluvium deposits extend more than 25 km to the east of the present-day edge of the main body of contiguous rock salt. The margin could have receded this distance during the past several million years. From an environmental perspective, the continued leaching of the Hutchinson Salt is a major concern. This predominantly natural dissolution occurs in a broad zone across the central part of the State and adversely affects groundwater and surface-water quality as nonpoint source pollution. Significant surface subsidence occurs as well. Most of these subsidence features have formed gradually; others developed in a more catastrophic manner. The latter in particular pose real threats to roadways, railways, and buried oil and gas pipelines. In an effort to further clarify the process of natural salt dissolution in central Kansas and with the long-term goal of mitigating the adverse environmental affects of such leaching, the Kansas Geological Survey acquired a 4-km seismic profile across the eastern margin of the Hutchinson Salt in the Punkin Center area of central Kansas. The interpretation of these seismic data (and supporting surficial and borehole geologic control) is consistent with several hypotheses regarding the process and mechanisms of dissolution. More specifically these data support the theses that: 1. (1) Dissolution along the active eastern margin of the Hutchinson Salt Member was initiated during late Tertiary. Leaching has resulted in the steady westward migration of the eastern margin, surface subsidence, and the contemporaneous deposition of predominantly valley-filling Quarternary alluvium. 2. (2) Along the active eastern margin, the rock salt has been leached vertically from the top down, and horizontally along the uppermost remnant bedded soluble layer(s). As a result, the eastern margin thickens gradually (up to 90 m) and in a stepwise manner from east to west for distances on the order 5-15 km. 3. (3) In places, the Hutchinson Salt Member has been leached locally along NNE-trending paleoshear zones situated to the west of the present-day edge of the main body of contiguous rock salt. Leaching at these sites initiated when the main dissolution front impinged upon preexisting shear zones. ?? 1994.

Rates and mechanisms of uranyl oxyhydroxide mineral dissolution

NASA Astrophysics Data System (ADS)

Reinoso-Maset, Estela; Steefel, Carl I.; Um, Wooyong; Chorover, Jon; O'Day, Peggy A.

2017-06-01

Uranyl oxyhydroxide minerals are important weathering products in uranium-contaminated surface and subsurface environments that regulate dissolved uranium (U) concentrations. However, dissolution rates for this class of minerals and associated dissolution mechanisms have not been previously reported for circumneutral pH conditions, particularly for the case of flow through porous media. In this work, the dissolution rates of K- and Na-compreignacite (K2(UO2)6O4(OH)6·8H2O and Na2(UO2)6O4(OH)6·8H2O, respectively) were measured using flow-through columns reacted with two simulated background porewater (BPW) solutions of low and high dissolved carbonate concentration (ca. 0.2 and 2.8 mmol L-1). Column materials were characterized before and after reaction with electron microscopy, bulk chemistry, and EXAFS to identify structural and chemical changes during dissolution and to obtain insight into molecular-scale processes. The reactive transport code CrunchFlow was used to calculate overall dissolution rates while accounting for fluid transport and changes in mineral volume and reactive surface area, and results were compared to steady-state dissolution rate calculations. In low carbonate BPW systems, interlayer K and Na were initially leached from both minerals, and in Na-compreignacite, K and minor divalent cations from the input solution were incorporated into the mineral structure. Results of characterization analyses suggested that after reaction both K- and Na-compreignacite resembled a disordered K-compreignacite with altered surfaces. A 10-fold increase in dissolved carbonate concentration and corresponding increase in pH (from 6.65 to 8.40) resulted in a net removal of 58-87% of total U mass from the columns, compared to <1% net loss in low carbonate BPW systems. Steady-state release of dissolved U was not observed with high carbonate solutions and post-reaction characterizations indicated a lack of development of leached or altered surfaces. Dissolution rates (normalized to specific surface area) were 2.5-3 orders-of-magnitude faster in high versus low carbonate BPW systems, with Na-compreignacite dissolving more rapidly than K-compreignacite under both BPW conditions, possibly due to greater ion exchange (1.57 · 10-10 vs. 1.28 · 10-13 mol m-2 s-1 [log R = -9.81 and -12.89] and 5.79 · 10-10 vs. 3.71 · 10-13 mol m-2 s-1 [log R = -9.24 and -12.43] for K- and Na-compreignacite, respectively). Experimental and spectroscopic results suggest that the dissolution rate is controlled by bond breaking of a uranyl group and detachment from polyhedral layers of the mineral structure. With higher dissolved carbonate concentrations, this rate-determining step is accelerated by the formation of Ca-uranyl carbonate complexes (dominant species under these conditions), which resulted in an increase of the dissolution rates. Optimization of both dissolution rate and mineral volume fraction in the reactive transport model to account for U mass removal during dissolution more accurately reproduced effluent data in high carbonate systems, and resulted in faster overall rates compared with a steady-state dissolution assumption. This study highlights the importance of coupling reaction and transport processes during the quantification of mineral dissolution rates to accurately predict the fate of contaminants such as U in porous geomedia.

DISSOLUTION OF PLUTONIUM METAL IN 8-10 M NITRIC ACID

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rudisill, T.; Pierce, R.

2012-02-21

The H-Canyon facility will be used to dissolve Pu metal for subsequent purification and conversion to plutonium dioxide (PuO{sub 2}) using Phase II of HB-Line. To support the new mission, the development of a Pu metal dissolution flowsheet which utilizes concentrated (8-10 M) nitric acid (HNO{sub 3}) solutions containing potassium fluoride (KF) is required. Dissolution of Pu metal in concentrated HNO{sub 3} is desired to eliminate the need to adjust the solution acidity prior to purification by anion exchange. The preferred flowsheet would use 8-10 M HNO{sub 3}, 0.015-0.07 M KF, and 0.5-1.0 g/L Gd to dissolve the Pu upmore » to 6.75 g/L. An alternate flowsheet would use 8-10 M HNO{sub 3}, 0.1-0.2 M KF, and 1-2 g/L B to dissolve the Pu. The targeted average Pu metal dissolution rate is 20 mg/min-cm{sup 2}, which is sufficient to dissolve a 'standard' 2250-g Pu metal button in 24 h. Plutonium metal dissolution rate measurements showed that if Gd is used as the nuclear poison, the optimum dissolution conditions occur in 10 M HNO{sub 3}, 0.04-0.05 M KF, and 0.5-1.0 g/L Gd at 112 to 116 C (boiling). These conditions will result in an estimated Pu metal dissolution rate of {approx}11-15 mg/min-cm{sup 2} and will result in dissolution times of 36-48 h for standard buttons. The recommended minimum and maximum KF concentrations are 0.03 M and 0.07 M, respectively. The maximum KF concentration is dictated by a potential room-temperature Pu-Gd-F precipitation issue at low Pu concentrations. The purpose of the experimental work described in this report was two-fold. Initially a series of screening experiments was performed to measure the dissolution rate of Pu metal as functions of the HNO{sub 3}, KF, and Gd or B concentrations. The objective of the screening tests was to propose optimized conditions for subsequent flowsheet demonstration tests. Based on the rate measurements, this study found that optimal dissolution conditions in solutions containing 0.5-1.0 g/L Gd occurred in 8-10 M HNO{sub 3} with 0.04-0.05 M KF at 112 to 116 C (boiling). The testing also showed that solutions containing 8-10 M HNO{sub 3}, 0.1-0.2 M KF, and 1-2 g/L B achieved acceptable dissolution rates in the same temperature range. To confirm that conditions identified by the dissolution rate measurements for solutions containing Gd or B can be used to dissolve Pu metal up to 6.75 g/L in the presence of Fe, demonstration experiments were performed using concentrations in the optimal ranges. In two of the demonstration experiments using Gd and in one experiment using B, the offgas generation during the dissolution was measured and samples were analyzed for H{sub 2}. The experimental methods used to perform the dissolution rate measurements and flowsheet demonstrations and a discussion of the results are presented.« less

Rates and mechanisms of uranyl oxyhydroxide mineral dissolution

DOE Office of Scientific and Technical Information (OSTI.GOV)

Reinoso-Maset, Estela; Steefel, Carl I.; Um, Wooyong

Uranyl oxyhydroxide minerals are important weathering products in uranium-contaminated surface and subsurface environments that regulate dissolved uranium concentrations. However, dissolution rates for this class of minerals and associated dissolution mechanisms have not been previously reported for circumneutral pH conditions, particularly for the case of flow through porous media. In this paper, the dissolution rates of K- and Na-compreignacite (K 2(UO 2) 6O 4(OH) 6·8H 2O and Na 2(UO 2) 6O 4(OH) 6·8H 2O respectively) were measured using flow-through columns reacted with two simulated background porewater (BPW) solutions of low and high dissolved total carbonate content (ca. 0.2 and 2.8 mmolmore » L -1). Column materials were characterized before and after reaction with electron microscopy, bulk chemistry, and EXAFS to identify structural and chemical changes during dissolution and to obtain insight into molecular-scale processes. The reactive transport code CrunchFlow was used to calculate overall dissolution rates while accounting for fluid transport and changes in mineral volume and reactive surface area and results were compared to steady-state dissolution rate calculations. In low carbonate BPW systems, interlayer K and Na were initially leached from both minerals, and in Na-compreignacite, K and minor divalent cations from the input solution were incorporated into the mineral structure. Results of characterization analyses suggested that after reaction both K- and Na-compreignacite resembled a disordered K-compreignacite with altered surfaces. A 10-fold increase in dissolved carbonate concentration and corresponding increase in pH (from 6.65 to 8.40) resulted in a net removal of 58-87% of total uranium mass from the columns, compared to <1% net loss in low carbonate BPW systems. Steady-state release of dissolved uranium was not observed with high carbonate solutions and post-reaction characterizations indicated a lack of development of leached or altered surfaces. Dissolution rates (normalized to specific surface area) were about 2.5-3 orders-of-magnitude faster in high versus low carbonate BPW systems, with Na-compreignacite dissolving more rapidly than K-compreignacite under both BPW conditions, possibly due to greater ion exchange (1.57·10 -10 vs. 1.28·10 -13 mol m -2 s -1 [log R = -9.81 and -12.89] and 5.79·10 -10 vs. 3.71·10 -13 mol m -2 s -1 [log R = -9.24 and -12.43] for K- and Na-compreignacite respectively). Experimental and spectroscopic results suggest that the dissolution rate is controlled by bond breaking of a uranyl group and detachment from polyhedral layers of the mineral structure. With higher dissolved carbonate concentrations, this rate-determining step is accelerated by the formation of Ca-uranyl carbonate complexes (dominant species under these conditions), which resulted in an increase of the dissolution rates. Optimization of both dissolution rate and mineral volume fraction in the reactive transport model to account for uranium mass removal during dissolution more accurately reproduced effluent data in high carbonate systems, and resulted in faster overall rates compared with a steady-state dissolution assumption. Finally, this study highlights the importance of coupling reaction and transport processes during the quantification of mineral dissolution rates to accurately predict the fate of contaminants such as uranium in porous geomedia.« less

Rates and mechanisms of uranyl oxyhydroxide mineral dissolution

DOE PAGES

Reinoso-Maset, Estela; Steefel, Carl I.; Um, Wooyong; ...

2017-06-01

Uranyl oxyhydroxide minerals are important weathering products in uranium-contaminated surface and subsurface environments that regulate dissolved uranium concentrations. However, dissolution rates for this class of minerals and associated dissolution mechanisms have not been previously reported for circumneutral pH conditions, particularly for the case of flow through porous media. In this paper, the dissolution rates of K- and Na-compreignacite (K 2(UO 2) 6O 4(OH) 6·8H 2O and Na 2(UO 2) 6O 4(OH) 6·8H 2O respectively) were measured using flow-through columns reacted with two simulated background porewater (BPW) solutions of low and high dissolved total carbonate content (ca. 0.2 and 2.8 mmolmore » L -1). Column materials were characterized before and after reaction with electron microscopy, bulk chemistry, and EXAFS to identify structural and chemical changes during dissolution and to obtain insight into molecular-scale processes. The reactive transport code CrunchFlow was used to calculate overall dissolution rates while accounting for fluid transport and changes in mineral volume and reactive surface area and results were compared to steady-state dissolution rate calculations. In low carbonate BPW systems, interlayer K and Na were initially leached from both minerals, and in Na-compreignacite, K and minor divalent cations from the input solution were incorporated into the mineral structure. Results of characterization analyses suggested that after reaction both K- and Na-compreignacite resembled a disordered K-compreignacite with altered surfaces. A 10-fold increase in dissolved carbonate concentration and corresponding increase in pH (from 6.65 to 8.40) resulted in a net removal of 58-87% of total uranium mass from the columns, compared to <1% net loss in low carbonate BPW systems. Steady-state release of dissolved uranium was not observed with high carbonate solutions and post-reaction characterizations indicated a lack of development of leached or altered surfaces. Dissolution rates (normalized to specific surface area) were about 2.5-3 orders-of-magnitude faster in high versus low carbonate BPW systems, with Na-compreignacite dissolving more rapidly than K-compreignacite under both BPW conditions, possibly due to greater ion exchange (1.57·10 -10 vs. 1.28·10 -13 mol m -2 s -1 [log R = -9.81 and -12.89] and 5.79·10 -10 vs. 3.71·10 -13 mol m -2 s -1 [log R = -9.24 and -12.43] for K- and Na-compreignacite respectively). Experimental and spectroscopic results suggest that the dissolution rate is controlled by bond breaking of a uranyl group and detachment from polyhedral layers of the mineral structure. With higher dissolved carbonate concentrations, this rate-determining step is accelerated by the formation of Ca-uranyl carbonate complexes (dominant species under these conditions), which resulted in an increase of the dissolution rates. Optimization of both dissolution rate and mineral volume fraction in the reactive transport model to account for uranium mass removal during dissolution more accurately reproduced effluent data in high carbonate systems, and resulted in faster overall rates compared with a steady-state dissolution assumption. Finally, this study highlights the importance of coupling reaction and transport processes during the quantification of mineral dissolution rates to accurately predict the fate of contaminants such as uranium in porous geomedia.« less

Acid mine drainage

USGS Publications Warehouse

Bigham, Jerry M.; Cravotta, Charles A.

2016-01-01

Acid mine drainage (AMD) consists of metal-laden solutions produced by the oxidative dissolution of iron sulfide minerals exposed to air, moisture, and acidophilic microbes during the mining of coal and metal deposits. The pH of AMD is usually in the range of 2–6, but mine-impacted waters at circumneutral pH (5–8) are also common. Mine drainage usually contains elevated concentrations of sulfate, iron, aluminum, and other potentially toxic metals leached from rock that hydrolyze and coprecipitate to form rust-colored encrustations or sediments. When AMD is discharged into surface waters or groundwaters, degradation of water quality, injury to aquatic life, and corrosion or encrustation of engineered structures can occur for substantial distances. Prevention and remediation strategies should consider the biogeochemical complexity of the system, the longevity of AMD pollution, the predictive power of geochemical modeling, and the full range of available field technologies for problem mitigation.

Hot corrosion and high temperature corrosion behavior of a new gas turbine material -- alloy 603GT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Agarwal, D.C.; Brill, U.; Klower, J.

1998-12-31

Salt deposits encountered in a variety of high temperature processes have caused premature failures in heat exchangers and superheater tubes in pulp and paper recovery boilers, waste incinerators and coal gasifiers. Molten salt corrosion studies in both land based and air craft turbines have been the subject of intense study by many researchers. This phenomenon referred to as ``hot corrosion`` has primarily been attributed to corrosion by alkali sulfates, and there is somewhat general agreement in the literature that this is caused by either basic or acidic dissolution (fluxing) of the protective metal oxide layers by complex salt deposits containingmore » both sulfates and chlorides. This paper describes experimental studies conducted on the hot corrosion behavior of a new Ni-Cr-Al alloy 603GT (UNS N06603) in comparison to some commercially established alloys used in gas turbine components.« less

Mine waters: Acidic to circumneutral

USGS Publications Warehouse

Nordstrom, D. Kirk

2011-01-01

Acid mine waters, often containing toxic concentrations of Fe, Al, Cu, Zn, Cd, Pb, Ni, Co, and Cr, can be produced from the mining of coal and metallic deposits. Values of pH for acid mine waters can range from –3.5 to 5, but even circumneutral (pH ≈ 7) mine waters can have high concentrations of As, Sb, Mo, U, and F. When mine waters are discharged into streams, lakes, and the oceans, serious degradation of water quality and injury to aquatic life can ensue, especially when tailings impoundments break suddenly. The main acid-producing process is the exposure of pyrite to air and water, which promotes oxidative dissolution, a reaction catalyzed by microbes. Current and future mining should plan for the prevention and remediation of these contaminant discharges by the application of hydrogeochemical principles and available technologies, which might include remining and recycling of waste materials.

Air pollution-aerosol interactions produce more bioavailable iron for ocean ecosystems.

PubMed

Li, Weijun; Xu, Liang; Liu, Xiaohuan; Zhang, Jianchao; Lin, Yangting; Yao, Xiaohong; Gao, Huiwang; Zhang, Daizhou; Chen, Jianmin; Wang, Wenxing; Harrison, Roy M; Zhang, Xiaoye; Shao, Longyi; Fu, Pingqing; Nenes, Athanasios; Shi, Zongbo

2017-03-01

It has long been hypothesized that acids formed from anthropogenic pollutants and natural emissions dissolve iron (Fe) in airborne particles, enhancing the supply of bioavailable Fe to the oceans. However, field observations have yet to provide indisputable evidence to confirm this hypothesis. Single-particle chemical analysis for hundreds of individual atmospheric particles collected over the East China Sea shows that Fe-rich particles from coal combustion and steel industries were coated with thick layers of sulfate after 1 to 2 days of atmospheric residence. The Fe in aged particles was present as a "hotspot" of (insoluble) iron oxides and throughout the acidic sulfate coating in the form of (soluble) Fe sulfate, which increases with degree of aging (thickness of coating). This provides the "smoking gun" for acid iron dissolution, because iron sulfate was not detected in the freshly emitted particles and there is no other source or mechanism of iron sulfate formation in the atmosphere.

EERC pilot-scale CFBC evaluation facility Project CFB test results. Topical report, Task 7.30

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mann, M.D.; Hajicek, D.R.; Henderson, A.K.

Project CFB was initiated at the University of North Dakota Energy and Environmental Research Center (EERC) in May 1988. Specific goals of the project were to (1) construct a circulating fluidized-bed combustor (CFBC) facility representative of the major boiler vendors` designs with the capability of producing scalable data, (2) develop a database for use in making future evaluations of CFBC technology, and (3) provide a facility for evaluating fuels, free of vendor bias for use in the - energy industry. Five coals were test-burned in the 1-MWth unit: North Dakota and Asian lignites, a Wyoming subbituminous, and Colorado and Pennsylvaniamore » bituminous coats. A total of 54 steady-state test periods were conducted, with the key test parameters being the average combustor temperature, excess air, superficial gas velocity, calcium-to-sulfur molar ratio, and the primary air-to-secondary air split. The capture for a coal fired in a CFBC is primarily dependent upon the total alkali-to-sulfur ratio. The required alkali-to ratio for 90% sulfur retention ranged from 1.4 to 4.9, depending upon coal type. While an alkali-to-ratio of 4.9 was required to meet 90% sulfur retention for the Salt Creek coal versus 1.4 for the Asian lignite, the total amount of sorbent addition required is much less for the Salt Creek coal, 4.2 pound sorbent per million Btu coal input, versus 62 pound/million Btu for the Asian lignite. The bituminous coals tested show optimal capture at combustor temperatures of approximately 1550{degree}F, with low-rank coals having optimal sulfur capture approximately 100{degree}F lower.« less

EERC pilot-scale CFBC evaluation facility Project CFB test results

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mann, M.D.; Hajicek, D.R.; Henderson, A.K.

Project CFB was initiated at the University of North Dakota Energy and Environmental Research Center (EERC) in May 1988. Specific goals of the project were to (1) construct a circulating fluidized-bed combustor (CFBC) facility representative of the major boiler vendors' designs with the capability of producing scalable data, (2) develop a database for use in making future evaluations of CFBC technology, and (3) provide a facility for evaluating fuels, free of vendor bias for use in the - energy industry. Five coals were test-burned in the 1-MWth unit: North Dakota and Asian lignites, a Wyoming subbituminous, and Colorado and Pennsylvaniamore » bituminous coats. A total of 54 steady-state test periods were conducted, with the key test parameters being the average combustor temperature, excess air, superficial gas velocity, calcium-to-sulfur molar ratio, and the primary air-to-secondary air split. The capture for a coal fired in a CFBC is primarily dependent upon the total alkali-to-sulfur ratio. The required alkali-to ratio for 90% sulfur retention ranged from 1.4 to 4.9, depending upon coal type. While an alkali-to-ratio of 4.9 was required to meet 90% sulfur retention for the Salt Creek coal versus 1.4 for the Asian lignite, the total amount of sorbent addition required is much less for the Salt Creek coal, 4.2 pound sorbent per million Btu coal input, versus 62 pound/million Btu for the Asian lignite. The bituminous coals tested show optimal capture at combustor temperatures of approximately 1550[degree]F, with low-rank coals having optimal sulfur capture approximately 100[degree]F lower.« less

CoalFleet RD&D augmentation plan for integrated gasification combined cycle (IGCC) power plants

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

2007-01-15

To help accelerate the development, demonstration, and market introduction of integrated gasification combined cycle (IGCC) and other clean coal technologies, EPRI formed the CoalFleet for Tomorrow initiative, which facilitates collaborative research by more than 50 organizations from around the world representing power generators, equipment suppliers and engineering design and construction firms, the U.S. Department of Energy, and others. This group advised EPRI as it evaluated more than 120 coal-gasification-related research projects worldwide to identify gaps or critical-path activities where additional resources and expertise could hasten the market introduction of IGCC advances. The resulting 'IGCC RD&D Augmentation Plan' describes such opportunitiesmore » and how they could be addressed, for both IGCC plants to be built in the near term (by 2012-15) and over the longer term (2015-25), when demand for new electric generating capacity is expected to soar. For the near term, EPRI recommends 19 projects that could reduce the levelized cost-of-electricity for IGCC to the level of today's conventional pulverized-coal power plants with supercritical steam conditions and state-of-the-art environmental controls. For the long term, EPRI's recommended projects could reduce the levelized cost of an IGCC plant capturing 90% of the CO{sub 2} produced from the carbon in coal (for safe storage away from the atmosphere) to the level of today's IGCC plants without CO{sub 2} capture. EPRI's CoalFleet for Tomorrow program is also preparing a companion RD&D augmentation plan for advanced-combustion-based (i.e., non-gasification) clean coal technologies (Report 1013221). 7 refs., 30 figs., 29 tabs., 4 apps.« less

30 CFR 939.764 - Process for designating areas unsuitable for surface coal mining operations.

Code of Federal Regulations, 2014 CFR

2014-07-01

... Mining Operations, pertaining to petitioning, initial processing, hearing requirements, decisions, data base and inventory systems, public information, and regulatory responsibilities shall become applicable...

30 CFR 903.764 - Process for designating areas unsuitable for surface coal mining operations.

Code of Federal Regulations, 2014 CFR

2014-07-01

... Mining Operations, pertaining to petitions, initial processing, hearing requirements, decisions, data base and inventory systems, public information, and regulatory responsibilities, applies to surface...

30 CFR 939.764 - Process for designating areas unsuitable for surface coal mining operations.

Code of Federal Regulations, 2013 CFR

2013-07-01

... Mining Operations, pertaining to petitioning, initial processing, hearing requirements, decisions, data base and inventory systems, public information, and regulatory responsibilities shall become applicable...

30 CFR 903.764 - Process for designating areas unsuitable for surface coal mining operations.

Code of Federal Regulations, 2012 CFR

2012-07-01

... Mining Operations, pertaining to petitions, initial processing, hearing requirements, decisions, data base and inventory systems, public information, and regulatory responsibilities, applies to surface...

30 CFR 903.764 - Process for designating areas unsuitable for surface coal mining operations.

Code of Federal Regulations, 2011 CFR

2011-07-01

... Mining Operations, pertaining to petitions, initial processing, hearing requirements, decisions, data base and inventory systems, public information, and regulatory responsibilities, applies to surface...

30 CFR 939.764 - Process for designating areas unsuitable for surface coal mining operations.

Code of Federal Regulations, 2012 CFR

2012-07-01

... Mining Operations, pertaining to petitioning, initial processing, hearing requirements, decisions, data base and inventory systems, public information, and regulatory responsibilities shall become applicable...

30 CFR 939.764 - Process for designating areas unsuitable for surface coal mining operations.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Mining Operations, pertaining to petitioning, initial processing, hearing requirements, decisions, data base and inventory systems, public information, and regulatory responsibilities shall become applicable...

30 CFR 939.764 - Process for designating areas unsuitable for surface coal mining operations.

Code of Federal Regulations, 2011 CFR

2011-07-01

... Mining Operations, pertaining to petitioning, initial processing, hearing requirements, decisions, data base and inventory systems, public information, and regulatory responsibilities shall become applicable...

30 CFR 903.764 - Process for designating areas unsuitable for surface coal mining operations.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Mining Operations, pertaining to petitions, initial processing, hearing requirements, decisions, data base and inventory systems, public information, and regulatory responsibilities, applies to surface...

Leaching characteristics of toxic constituents from coal fly ash mixed soils under the influence of pH

DOE Office of Scientific and Technical Information (OSTI.GOV)

Komonweeraket, Kanokwan; Cetin, Bora, E-mail: bora.cetin@sdsmt.edu; Benson, Craig H., E-mail: chbenson@wisc.edu

Highlights: • The impact of pH on the leaching of elements and metals from fly ash mixed soils. • Generally Ca, Cd, Mg, and Sr follows a cationic leaching pattern. • The leaching of As and Se shows an oxyanionic leaching pattern. • The leaching behavior of elements does not change based on material type. • Different fly ash types show different abilities in immobilizing trace elements. - Abstract: Leaching behaviors of Arsenic (As), Barium (Ba), Calcium (Ca), Cadmium (Cd), Magnesium (Mg), Selenium (Se), and Strontium (Sr) from soil alone, coal fly ash alone, and soil-coal fly ash mixtures, weremore » studied at a pH range of 2–14 via pH-dependent leaching tests. Seven different types of soils and coal fly ashes were tested. Results of this study indicated that Ca, Cd, Mg, and Sr showed cationic leaching pattern while As and Se generally follows an oxyanionic leaching pattern. On the other hand, leaching of Ba presented amphoteric-like leaching pattern but less pH-dependent. In spite of different types and composition of soil and coal fly ash investigated, the study reveals the similarity in leaching behavior as a function of pH for a given element from soil, coal fly ash, and soil-coal fly ash mixtures. The similarity is most likely due to similar controlling mechanisms (e.g., solubility, sorption, and solid-solution formation) and similar controlling factors (e.g., leachate pH and redox conditions). This offers the opportunity to transfer knowledge of coal fly ash that has been extensively characterized and studied to soil stabilized with coal fly ash. It is speculated that unburned carbon in off-specification coal fly ashes may provide sorption sites for Cd resulting in a reduction in concentration of these elements in leachate from soil-coal fly ash mixture. Class C fly ash provides sufficient CaO to initiate the pozzolanic reaction yielding hydrated cement products that oxyanions, including As and Se, can be incorporated into.« less

(Initiation of strategic assessment of fossil options, Phase 2). Summary. Progress report, November 1981-February 1982. [USA; coal transhipment capacity in 1990 for 37 ports

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kocur, G.; Adler, T.J.

1982-02-23

The export coal transportation study has proceeded through the first two subtasks. Figure 1 shows a comparison between past and projected US coal export demand and US port coal transshipment capacities. Projected export demand was taken from the MIT World Coal Study, and projected port capacities were determined primarily by personal communications with port managers. Table 1 details projected 1990 capacities at each major port, with a maximum-minimum range indicating undertain projects. The obvious observation from these data is the massive discrepancy between projected capacities and projected export movements. It is very likely that many ports have publicized ambitious expansionmore » plans in order to discourage competing ports from expanding. In addition, the excess port capacity could be used for exports of, for example, iron ore and grain. Nonetheless, Fig. 1 does indicate some need to determine which subset of ports will lie on the most cost-effective routing from mine to ultimate destination and which thus deserve the largest investments. The survey of rail export (steam) coal rates began with an identification of representative mines (13) to port (19) movement (total of 54 allowable). Per carload rail rates were then obtained for approximately 25 of these movements. Regression analyses were performed relating these rates to shipping distance, and other factors. 1 figure, 1 table.« less

Potassium dichromate method of coal gasification the study of the typical organic compounds in water

NASA Astrophysics Data System (ADS)

Quan, Jiankang; Qu, Guangfei; Dong, Zhanneng; Lu, Pei; Cai, Yingying; Wang, Shibo

2017-05-01

The national standard method is adopted in this paper the water - digestion spectrophotometry for determination of the chemical oxygen demand (COD), after ultrasonic processing of coal gasification water for CODCr measurement. Using the control variable method, measured in different solution pH, ultrasonic frequency, ultrasonic power, reaction conditions of different initial solution concentration, the change of coal gasification water CODCr value under the action of ultrasonic, the experimental results shows that appear when measurement is allowed to fluctuate, data, in order to explain the phenomenon we adopt the combination of the high performance liquid chromatography and mass spectrometry before and after ultrasonic coal gasification qualitative analysis on composition of organic matter in water. To raw water sample chromatography - mass spectrometry (GC/MS) analysis, combined with the spectra analysis of each peak stands for material, select coal gasification typical organic substances in water, with the method of single digestion, the equivalent CODCr values measured after digestion. Order to produce, coal gasification water contained high concentration organic wastewater, such as the national standard method is adopted to eliminate the organic material, therefore to measure the CODCr value is lower than actual CODCr value of the emergence of the phenomenon, the experiment of the effect of ultrasound [9-13] is promote the complex organic chain rupture, also explains the actual measurement data fluctuation phenomenon in the experiment.

Dissolution of a metal oxide film during titanium carbide synthesis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bloshenko, V.N.; Bokii, V.A.; Borovinskaya, I.P.

1985-05-01

Oxygen is most difficult to remove during combustion of the mixture Ti + C. Its fundamental mass is in two states in the initial charge: part of the oxygen is dissolved in the titanium particles; the rest is bound in the metal oxide film (an insignificant part of the oxygen is in the adsorbed state in the carbon and titanium particles). On the basis of the results of vacuum annealing of specimens from a Ti + C mixture, the possibility is shown in this paper for dissolution of the intrinsic oxide film by titanium particles during residency of these particlesmore » in the heating zone of the combustion wave.« less

A model for lignin alteration - Part II: Numerical model of natural gas generation and application to the Piceance Basin, Western Colorado

USGS Publications Warehouse

Payne, D.F.; Ortoleva, P.J.

2001-01-01

The model presented here simulates a network of parallel and sequential reactions that describe the structural and chemical transformation of lignin-derived sedimentary organic matter (SOM) and the resulting generation of mobile species from shallow burial to approximately low-volatile bituminous rank. The model is calibrated to the Upper Cretaceous Williams Fork Formation coal of the Piceance Basin at the Multi-Well Experiment (MWX) Site, assuming this coal is largely derived from lignin. The model calculates the content of functional groups on the residual molecular species, C, H, and O elemental weight percents of the residual species, and moles of residual molecular species and mobile species (including components of natural gas) through time. The model is generally more sensitive to initial molecular structure of the lignin-derived molecule and the H2O content of the system than to initial temperature, as the former affect the fundamental reaction paths. The model is used to estimate that a total of 314 trillion cubic feet (tcf) of methane is generated by the Williams Fork coal over the basin history. ?? 2001 Elsevier Science Ltd. All rights reserved.

30 CFR 922.764 - Process for designating areas unsuitable for surface coal mining operations.

Code of Federal Regulations, 2013 CFR

2013-07-01

... Mining Operations, pertaining to petitioning, initial processing, hearing requirements, decisions, data base and inventory systems, public information, and regulatory responsibilities shall apply to surface...

30 CFR 922.764 - Process for designating areas unsuitable for surface coal mining operations.

Code of Federal Regulations, 2011 CFR

2011-07-01

... Mining Operations, pertaining to petitioning, initial processing, hearing requirements, decisions, data base and inventory systems, public information, and regulatory responsibilities shall apply to surface...

30 CFR 947.764 - Process for designating areas unsuitable for surface coal mining operations.

Code of Federal Regulations, 2012 CFR

2012-07-01

... Mining Operations, pertaining to petitioning, initial processing, hearing requirements, decisions, data base and inventory systems, public information, and regulatory responsibilities shall apply to surface...

30 CFR 941.764 - Process for designating areas unsuitable for surface coal mining operations.

Code of Federal Regulations, 2011 CFR

2011-07-01

... Mining Operations, pertaining to petitioning, initial processing, hearing requirements, decisions, data base and inventory systems, public information, and regulatory responsibilities shall apply to surface...

30 CFR 922.764 - Process for designating areas unsuitable for surface coal mining operations.

Code of Federal Regulations, 2012 CFR

2012-07-01

... Mining Operations, pertaining to petitioning, initial processing, hearing requirements, decisions, data base and inventory systems, public information, and regulatory responsibilities shall apply to surface...

30 CFR 912.764 - Process for designating areas unsuitable for surface coal mining operations.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Mining Operations, pertaining to petitioning, initial processing, hearing requirements, decisions, data base and inventory systems, public information, and regulatory responsibilities shall apply to surface...

30 CFR 905.764 - Process for designating areas unsuitable for surface coal mining operations.

Code of Federal Regulations, 2011 CFR

2011-07-01

... Mining Operations, pertaining to petitions, initial processing, hearing requirements, decisions, data base and inventory systems, public information, and regulatory responsibilities shall apply to surface...

30 CFR 910.764 - Process for designating areas unsuitable for surface coal mining operations.

Code of Federal Regulations, 2014 CFR

2014-07-01

... Mining Operations, pertaining to petitioning, initial processing, hearing requirements, decisions, data base and inventory systems, public information, and regulatory responsibilities shall apply to surface...

30 CFR 905.764 - Process for designating areas unsuitable for surface coal mining operations.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Mining Operations, pertaining to petitions, initial processing, hearing requirements, decisions, data base and inventory systems, public information, and regulatory responsibilities shall apply to surface...

30 CFR 905.764 - Process for designating areas unsuitable for surface coal mining operations.

Code of Federal Regulations, 2014 CFR

2014-07-01

... Mining Operations, pertaining to petitions, initial processing, hearing requirements, decisions, data base and inventory systems, public information, and regulatory responsibilities shall apply to surface...

30 CFR 941.764 - Process for designating areas unsuitable for surface coal mining operations.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Mining Operations, pertaining to petitioning, initial processing, hearing requirements, decisions, data base and inventory systems, public information, and regulatory responsibilities shall apply to surface...

30 CFR 912.764 - Process for designating areas unsuitable for surface coal mining operations.

Code of Federal Regulations, 2011 CFR

2011-07-01

... Mining Operations, pertaining to petitioning, initial processing, hearing requirements, decisions, data base and inventory systems, public information, and regulatory responsibilities shall apply to surface...

30 CFR 941.764 - Process for designating areas unsuitable for surface coal mining operations.

Code of Federal Regulations, 2013 CFR

2013-07-01

... Mining Operations, pertaining to petitioning, initial processing, hearing requirements, decisions, data base and inventory systems, public information, and regulatory responsibilities shall apply to surface...

30 CFR 922.764 - Process for designating areas unsuitable for surface coal mining operations.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Mining Operations, pertaining to petitioning, initial processing, hearing requirements, decisions, data base and inventory systems, public information, and regulatory responsibilities shall apply to surface...

30 CFR 947.764 - Process for designating areas unsuitable for surface coal mining operations.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Mining Operations, pertaining to petitioning, initial processing, hearing requirements, decisions, data base and inventory systems, public information, and regulatory responsibilities shall apply to surface...

30 CFR 947.764 - Process for designating areas unsuitable for surface coal mining operations.

Code of Federal Regulations, 2014 CFR

2014-07-01

... Mining Operations, pertaining to petitioning, initial processing, hearing requirements, decisions, data base and inventory systems, public information, and regulatory responsibilities shall apply to surface...

30 CFR 941.764 - Process for designating areas unsuitable for surface coal mining operations.

Code of Federal Regulations, 2014 CFR

2014-07-01

... Mining Operations, pertaining to petitioning, initial processing, hearing requirements, decisions, data base and inventory systems, public information, and regulatory responsibilities shall apply to surface...

30 CFR 910.764 - Process for designating areas unsuitable for surface coal mining operations.

Code of Federal Regulations, 2012 CFR

2012-07-01

... Mining Operations, pertaining to petitioning, initial processing, hearing requirements, decisions, data base and inventory systems, public information, and regulatory responsibilities shall apply to surface...

30 CFR 910.764 - Process for designating areas unsuitable for surface coal mining operations.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Mining Operations, pertaining to petitioning, initial processing, hearing requirements, decisions, data base and inventory systems, public information, and regulatory responsibilities shall apply to surface...

30 CFR 910.764 - Process for designating areas unsuitable for surface coal mining operations.

Code of Federal Regulations, 2011 CFR

2011-07-01

... Mining Operations, pertaining to petitioning, initial processing, hearing requirements, decisions, data base and inventory systems, public information, and regulatory responsibilities shall apply to surface...

30 CFR 905.764 - Process for designating areas unsuitable for surface coal mining operations.

Code of Federal Regulations, 2012 CFR

2012-07-01

... Mining Operations, pertaining to petitions, initial processing, hearing requirements, decisions, data base and inventory systems, public information, and regulatory responsibilities shall apply to surface...

30 CFR 941.764 - Process for designating areas unsuitable for surface coal mining operations.

Code of Federal Regulations, 2012 CFR

2012-07-01

... Mining Operations, pertaining to petitioning, initial processing, hearing requirements, decisions, data base and inventory systems, public information, and regulatory responsibilities shall apply to surface...

30 CFR 912.764 - Process for designating areas unsuitable for surface coal mining operations.

Code of Federal Regulations, 2014 CFR

2014-07-01

... Mining Operations, pertaining to petitioning, initial processing, hearing requirements, decisions, data base and inventory systems, public information, and regulatory responsibilities shall apply to surface...

30 CFR 947.764 - Process for designating areas unsuitable for surface coal mining operations.

Code of Federal Regulations, 2011 CFR

2011-07-01

... Mining Operations, pertaining to petitioning, initial processing, hearing requirements, decisions, data base and inventory systems, public information, and regulatory responsibilities shall apply to surface...

30 CFR 947.764 - Process for designating areas unsuitable for surface coal mining operations.

Code of Federal Regulations, 2013 CFR

2013-07-01

... Mining Operations, pertaining to petitioning, initial processing, hearing requirements, decisions, data base and inventory systems, public information, and regulatory responsibilities shall apply to surface...

30 CFR 922.764 - Process for designating areas unsuitable for surface coal mining operations.

Code of Federal Regulations, 2014 CFR

2014-07-01

... Mining Operations, pertaining to petitioning, initial processing, hearing requirements, decisions, data base and inventory systems, public information, and regulatory responsibilities shall apply to surface...

30 CFR 912.764 - Process for designating areas unsuitable for surface coal mining operations.

Code of Federal Regulations, 2012 CFR

2012-07-01

... Mining Operations, pertaining to petitioning, initial processing, hearing requirements, decisions, data base and inventory systems, public information, and regulatory responsibilities shall apply to surface...

Coal Field Fire Fighting - Practiced methods, strategies and tactics

NASA Astrophysics Data System (ADS)

Wündrich, T.; Korten, A. A.; Barth, U. H.

2009-04-01

Subsurface coal fires destroy millions of tons of coal each year, have an immense impact to the ecological surrounding and threaten further coal reservoirs. Due to enormous dimensions a coal seam fire can develop, high operational expenses are needed. As part of the Sino-German coal fire research initiative "Innovative technologies for exploration, extinction and monitoring of coal fires in Northern China" the research team of University of Wuppertal (BUW) focuses on fire extinction strategies and tactics as well as aspects of environmental and health safety. Besides the choice and the correct application of different extinction techniques further factors are essential for the successful extinction. Appropriate tactics, well trained and protected personnel and the choice of the best fitting extinguishing agents are necessary for the successful extinction of a coal seam fire. The chosen strategy for an extinction campaign is generally determined by urgency and importance. It may depend on national objectives and concepts of coal conservation, on environmental protection (e.g. commitment to green house gases (GHG) reductions), national funding and resources for fire fighting (e.g. personnel, infrastructure, vehicles, water pipelines); and computer-aided models and simulations of coal fire development from self ignition to extinction. In order to devise an optimal fire fighting strategy, "aims of protection" have to be defined in a first step. These may be: - directly affected coal seams; - neighboring seams and coalfields; - GHG emissions into the atmosphere; - Returns on investments (costs of fire fighting compared to value of saved coal). In a further step, it is imperative to decide whether the budget shall define the results, or the results define the budget; i.e. whether there are fixed objectives for the mission that will dictate the overall budget, or whether the limited resources available shall set the scope within which the best possible results shall be achieved. For an effective and efficient fire fighting optimal tactics are requiered and can be divided into four fundamental tactics to control fire hazards: - Defense (digging away the coal, so that the coal can not begin to burn; or forming a barrier, so that the fire can not reach the not burning coal), - Rescue the coal (coal mining of a not burning seam), - Attack (active and direct cooling of burning seam), - Retreat (only monitoring till self-extinction of a burning seam). The last one is used when a fire exceeds the organizational and/or technical scope of a mission. In other words, "to control a coal fire" does not automatically and in all situations mean "to extinguish a coal fire". Best-practice tactics or a combination of them can be selected for control of a particular coal fire. For the extinguishing works different extinguishing agents are available. They can be applied by different application techniques and varying distinctive operating expenses. One application method may be the drilling of boreholes from the surface or covering the surface with low permeability soils. The mainly used extinction agents for coal field fire are as followed: Water (with or without additives), Slurry, Foaming mud/slurry, Inert gases, Dry chemicals and materials and Cryogenic agents. Because of its tremendous dimension and its complexity the worldwide challenge of coal fires is absolutely unique - it can only be solved with functional application methods, best fitting strategies and tactics, organisation and research as well as the dedication of the involved fire fighters, who work under extreme individual risks on the burning coal fields.

Influence of capsule shell composition on the performance indicators of hypromellose capsule in comparison to hard gelatin capsules.

PubMed

Al-Tabakha, Moawia M; Arida, Adi Issam; Fahelelbom, Khairi M S; Sadek, Bassem; Saeed, Dima Ahmed; Abu Jarad, Rami A; Jawadi, Jeevani

2015-01-01

The purpose of this study was to assess the in vitro performances of "vegetable" capsules in comparison to hard gelatin capsules in terms of shell weight variation, reaction to different humidity conditions, resistance to stress in the absence of moisture, powder leakage, disintegration and dissolution. Two types of capsules made of HPMC produced with (Capsule 2) or without (Capsule 3) a gelling agent and hard gelatin capsules (Capsule 1) were assessed. Shell weight variability was relatively low for all tested capsules shells. Although Capsule 1 had the highest moisture content under different humidity conditions, all capsule types were unable to protect the encapsulated hygroscopic polyvinylpyrrolidone (PVP) powder from surrounding humidity. The initial disintegration for all Capsule 1 occurred within 3 min, but for other types of capsules within 6 min (n = 18). Dissolution of acetaminophen was better when the deionized water (DIW) temperature increased from 32 to 42 °C in case of Capsule 1, but the effect of temperature was not significant for the other types of capsules. Acetaminphen dissolution from Capsule 1 was the fastest (i.e. >90% in 10 min) and independent of the media pH or contents unlike Capsule 2 which was influenced by the pH and dissolution medium contents. It is feasible to use hypromellose capsules shells with or without gelling agent for new lines of pharmaceutical products, however, there is a window for capsule shells manufacturing companies to improve the dissolution of their hypromellose capsules to match the conventional gelatin capsule shells and eventually replace them.

Interlaboratory studies on in vitro test methods for estimating in vivo resorption of calcium phosphate ceramics.

PubMed

Ito, Atsuo; Sogo, Yu; Yamazaki, Atsushi; Aizawa, Mamoru; Osaka, Akiyoshi; Hayakawa, Satoshi; Kikuchi, Masanori; Yamashita, Kimihiro; Tanaka, Yumi; Tadokoro, Mika; de Sena, Lídia Ágata; Buchanan, Fraser; Ohgushi, Hajime; Bohner, Marc

2015-10-01

A potential standard method for measuring the relative dissolution rate to estimate the resorbability of calcium-phosphate-based ceramics is proposed. Tricalcium phosphate (TCP), magnesium-substituted TCP (MgTCP) and zinc-substituted TCP (ZnTCP) were dissolved in a buffer solution free of calcium and phosphate ions at pH 4.0, 5.5 or 7.3 at nine research centers. Relative values of the initial dissolution rate (relative dissolution rates) were in good agreement among the centers. The relative dissolution rate coincided with the relative volume of resorption pits of ZnTCP in vitro. The relative dissolution rate coincided with the relative resorbed volume in vivo in the case of comparison between microporous MgTCPs with different Mg contents and similar porosity. However, the relative dissolution rate was in poor agreement with the relative resorbed volume in vivo in the case of comparison between microporous TCP and MgTCP due to the superimposition of the Mg-mediated decrease in TCP solubility on the Mg-mediated increase in the amount of resorption. An unambiguous conclusion could not be made as to whether the relative dissolution rate is predictive of the relative resorbed volume in vivo in the case of comparison between TCPs with different porosity. The relative dissolution rate may be useful for predicting the relative amount of resorption for calcium-phosphate-based ceramics having different solubility under the condition that the differences in the materials compared have little impact on the resorption process such as the number and activity of resorbing cells. The evaluation and subsequent optimization of the resorbability of calcium phosphate are crucial in the use of resorbable calcium phosphates. Although the resorbability of calcium phosphates has usually been evaluated in vivo, establishment of a standard in vitro method that can predict in vivo resorption is beneficial for accelerating development and commercialization of new resorbable calcium phosphate materials as well as reducing use of animals. However, there are only a few studies to propose such an in vitro method within which direct comparison was carried out between in vitro and in vivo resorption. We propose here an in vitro method based on measuring dissolution rate. The efficacy and limitations of the method were evaluated by international round-robin tests as well as comparison with in vivo resorption studies for future standardization. This study was carried out as one of Versailles Projects on Advanced Materials and Standards (VAMAS). Copyright © 2015 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

ISD3: a particokinetic model for predicting the combined effects of particle sedimentation, diffusion and dissolution on cellular dosimetry for in vitro systems.

PubMed

Thomas, Dennis G; Smith, Jordan N; Thrall, Brian D; Baer, Donald R; Jolley, Hadley; Munusamy, Prabhakaran; Kodali, Vamsi; Demokritou, Philip; Cohen, Joel; Teeguarden, Justin G

2018-01-25

The development of particokinetic models describing the delivery of insoluble or poorly soluble nanoparticles to cells in liquid cell culture systems has improved the basis for dose-response analysis, hazard ranking from high-throughput systems, and now allows for translation of exposures across in vitro and in vivo test systems. Complimentary particokinetic models that address processes controlling delivery of both particles and released ions to cells, and the influence of particle size changes from dissolution on particle delivery for cell-culture systems would help advance our understanding of the role of particles and ion dosimetry on cellular toxicology. We developed ISD3, an extension of our previously published model for insoluble particles, by deriving a specific formulation of the Population Balance Equation for soluble particles. ISD3 describes the time, concentration and particle size dependent dissolution of particles, their delivery to cells, and the delivery and uptake of ions to cells in in vitro liquid test systems. We applied the model to calculate the particle and ion dosimetry of nanosilver and silver ions in vitro after calibration of two empirical models, one for particle dissolution and one for ion uptake. Total media ion concentration, particle concentration and total cell-associated silver time-courses were well described by the model, across 2 concentrations of 20 and 110 nm particles. ISD3 was calibrated to dissolution data for 20 nm particles as a function of serum protein concentration, but successfully described the media and cell dosimetry time-course for both particles at all concentrations and time points. We also report the finding that protein content in media affects the initial rate of dissolution and the resulting near-steady state ion concentration in solution for the systems we have studied. By combining experiments and modeling, we were able to quantify the influence of proteins on silver particle solubility, determine the relative amounts of silver ions and particles in exposed cells, and demonstrate the influence of particle size changes resulting from dissolution on particle delivery to cells in culture. ISD3 is modular and can be adapted to new applications by replacing descriptions of dissolution, sedimentation and boundary conditions with those appropriate for particles other than silver.

Iron dissolution kinetics of mineral dust at low pH during simulated atmospheric processing

NASA Astrophysics Data System (ADS)

Shi, Z.; Bonneville, S.; Krom, M. D.; Carslaw, K. S.; Jickells, T. D.; Baker, A. R.; Benning, L. G.

2010-11-01

We investigated the iron (Fe) dissolution kinetics of African (Tibesti) and Asian (Beijing) dust samples at acidic pH with the aim of reproducing the low pH conditions in atmospheric aerosols. The Beijing dust and three size fractions of the Tibesti dust (<20 μm: PM20; <10 μm: PM10; and <2.5 μm: PM2.5) were dissolved at pH 1, 2 and/or 3 for up to 1000 h. In the first 10 min, all dust samples underwent an extremely fast Fe solubilisation. Subsequently, the Fe dissolution proceeded at a much slower rate before reaching a stable dissolution plateau. The time-dependant Fe dissolution datasets were best described by a model comprising three acid-extractable Fe pools each dissolving according to first-order kinetics. The dissolution rate constant k of each pool was independent of the source (Saharan or Asian) and the size (PM20, PM10 or PM2.5) of the dust but highly dependent on pH. The "fast" Fe pool had a k (25 h-1 at pH=1) of a similar magnitude to "dry" ferrihydrite nanoparticles and/or poorly crystalline Fe(III) oxyhydroxide, while the "intermediate" and "slow" Fe pools had k values respectively 50-60 times and 3000-4000 times smaller than the "fast" pool. The "slow" Fe pool was likely to consist of both crystalline Fe oxide phases (i.e., goethite and/or hematite) and Fe contained in the clay minerals. The initial mass of the "fast", "intermediate" and "slow" Fe pools represented respectively about 0.5-2%, 1-3% and 15-40% of the total Fe in the dust samples. Furthermore, we showed that in systems with low dust/liquid ratios, Fe can be dissolved from all three phases, whereas at high dust/liquid ratios (e.g., in aerosols), sufficient Fe is solubilised from the "fast" phase to dominate the Fe dissolved and to suppress the dissolution of Fe from the other Fe pools. These data demonstrated that dust/liquid ratio and pH are fundamental parameters controlling Fe dissolution kinetics in the dust. In order to reduce errors in atmospheric and climate models, these fundamental controlling factors need to be included.

Iron dissolution kinetics of mineral dust at low pH during simulated atmospheric processing

NASA Astrophysics Data System (ADS)

Shi, Z.; Bonneville, S.; Krom, M. D.; Carslaw, K. S.; Jickells, T. D.; Baker, A. R.; Benning, L. G.

2011-02-01

We investigated the iron (Fe) dissolution kinetics of African (Tibesti) and Asian (Beijing) dust samples at acidic pH with the aim of reproducing the low pH conditions in atmospheric aerosols. The Beijing dust and three size fractions of the Tibesti dust (<20 μm: PM20; <10 μm: PM10; and <2.5 μm: PM2.5) were dissolved at pH 1, 2 and/or 3 for up to 1000 h. In the first 10 min, all dust samples underwent an extremely fast Fe solubilisation. Subsequently, the Fe dissolution proceeded at a much slower rate before reaching a stable dissolution plateau. The time-dependant Fe dissolution datasets were best described by a model comprising three acid-extractable Fe pools each dissolving according to first-order kinetics. The dissolution rate constant k (h-1) of each pool was independent of the source (Saharan or Asian) and the size (PM20, PM10 or PM2.5) of the dust but highly dependent on pH. The "fast" Fe pool had a k (25 h-1 at pH = 1) of a similar magnitude to "dry" ferrihydrite nanoparticles and/or poorly crystalline Fe(III) oxyhydroxide, while the "intermediate" and "slow" Fe pools had k values respectively 50-60 times and 3000-4000 times smaller than the "fast" pool. The "slow" Fe pool was likely to consist of both crystalline Fe oxide phases (i.e., goethite and/or hematite) and Fe contained in the clay minerals. The initial mass of the "fast", "intermediate" and "slow" Fe pools represented respectively about 0.5-2%, 1-3% and 15-40% of the total Fe in the dust samples. Furthermore, we showed that in systems with low dust/liquid ratios, Fe can be dissolved from all three pools, whereas at high dust/liquid ratios (e.g., in aerosols), sufficient Fe may be solubilised from the "fast" phase to dominate the Fe dissolved and to suppress the dissolution of Fe from the other Fe pools. These data demonstrated that dust/liquid ratio and pH are fundamental parameters controlling Fe dissolution kinetics in the dust. In order to reduce errors in atmospheric and climate models, these fundamental controlling factors need to be included.

40 CFR 63.10011 - How do I demonstrate initial compliance with the emissions limits and work practice standards?

Code of Federal Regulations, 2013 CFR

2013-07-01

... Hazardous Air Pollutants: Coal- and Oil-Fired Electric Utility Steam Generating Units Testing and Initial... liquid oil-fired unit, and you use quarterly stack testing for HCl and HF plus site-specific parameter monitoring to demonstrate continuous performance, you must also establish a site-specific operating limit, in...

40 CFR 63.10011 - How do I demonstrate initial compliance with the emissions limits and work practice standards?

Code of Federal Regulations, 2014 CFR

2014-07-01

... Hazardous Air Pollutants: Coal- and Oil-Fired Electric Utility Steam Generating Units Testing and Initial... liquid oil-fired unit, and you use quarterly stack testing for HCl and HF plus site-specific parameter monitoring to demonstrate continuous performance, you must also establish a site-specific operating limit, in...

Symposium on surface coal mining and reclamation in the Northern Great Plains. Research on shrub establishment in reclamation of surface-mined lands

DOE Office of Scientific and Technical Information (OSTI.GOV)

Eddleman, L.E.

1980-01-01

Shrubs are an important component of plant communities in southeastern Montana. Re-establishment of the majority of native shrubs by seed on surface coal mine lands has not been generally successful. Field plantings at the Rosebud Mine of 25 shrub and half-shrub species were initiated in 1978 using seed from native populations. Three species Atriplex canescens, Atriplex nuttallii and Ceratoids lanata establish numerous seedlings in both wet and dry years. No emergence was obtained from 12 species.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Newell, J; Miller, D; Stone, M

The Savannah River National Laboratory (SRNL) was tasked to provide an assessment of the downstream impacts to the Defense Waste Processing Facility (DWPF) of decisions regarding the implementation of Al-dissolution to support sludge mass reduction and processing. Based on future sludge batch compositional projections from the Liquid Waste Organization's (LWO) sludge batch plan, assessments have been made with respect to the ability to maintain comparable projected operating windows for sludges with and without Al-dissolution. As part of that previous assessment, candidate frits were identified to provide insight into melt rate for average sludge batches representing with and without Al-dissolution flowsheets.more » Initial melt rate studies using the melt rate furnace (MRF) were performed using five frits each for Cluster 2 and Cluster 4 compositions representing average without and with Al-dissolution. It was determined, however, that the REDOX endpoint (Fe{sup 2+}/{Sigma}Fe for the glass) for Clusters 2 and 4 resulted in an overly oxidized feed which negatively affected the initial melt rate tests. After the sludge was adjusted to a more reduced state, additional testing was performed with frits that contained both high and low concentrations of sodium and boron oxides. These frits were selected strictly based on the ability to ascertain compositional trends in melt rate and did not necessarily apply to any acceptability criteria for DWPF processing. The melt rate data are in general agreement with historical trends observed at SRNL and during processing of SB3 (Sludge Batch 3)and SB4 in DWPF. When MAR acceptability criteria were applied, Frit 510 was seen to have the highest melt rate at 0.67 in/hr for Cluster 2 (without Al-dissolution), which is compositionally similar to SB4. For Cluster 4 (with Al-dissolution), which is compositionally similar to SB3, Frit 418 had the highest melt rate at 0.63 in/hr. Based on this data, there appears to be a slight advantage of the Frit 510 based system without Al-dissolution relative to the Frit 418 based system with Al-dissolution. Though the without aluminum dissolution scenario suggests a slightly higher melt rate with frit 510, several points must be taken into consideration: (1) The MRF does not have the ability to assess liquid feeds and, thus, rheology impacts. Instead, the MRF is a 'static' test bed in which a mass of dried melter feed (SRAT product plus frit) is placed in an 'isothermal' furnace for a period of time to assess melt rate. These conditions, although historically effective in terms of identifying candidate frits for specific sludge batches and mapping out melt rate versus waste loading trends, do not allow for assessments of the potential impact of feed rheology on melt rate. That is, if the rheological properties of the slurried melter feed resulted in the mounding of the feed in the melter (i.e., the melter feed was thick and did not flow across the cold cap), melt rate and/or melter operations (i.e., surges) could be negatively impacted. This could affect one or both flowsheets. (2) Waste throughput factors were not determined for Frit 510 and Frit 418 over multiple waste loadings. In order to provide insight into the mission life versus canister count question, one needs to define the maximum waste throughput for both flowsheets. Due to funding limitations, the melt rate testing only evaluated melt rate at a fixed waste loading. (3) DWPF will be processing SB5 through their facility in mid-November 2008. Insight into the over arching questions of melt rate, waste throughput, and mission life can be obtained directly from the facility. It is recommended that processing of SB5 through the facility be monitored closely and that data be used as input into the decision making process on whether to implement Al-dissolution for future sludge batches.« less

Pore-scale supercritical CO 2 dissolution and mass transfer under drainage conditions

DOE PAGES

Chang, Chun; Zhou, Quanlin; Oostrom, Mart; ...

2016-12-05

Recently, both core- and pore-scale imbibition experiments have shown non-equilibrium dissolution of supercritical CO 2 (scCO 2) and a prolonged depletion of residual scCO 2. In this paper, pore-scale scCO 2 dissolution and mass transfer under drainage conditions were investigated using a two-dimensional heterogeneous micromodel and a novel fluorescent water dye with a sensitive pH range between 3.7 and 6.5. Drainage experiments were conducted at 9 MPa and 40 °C by injecting scCO 2 into the sandstone-analogue pore network initially saturated by water without dissolved CO 2 (dsCO 2). During the experiments, time-lapse images of dye intensity, reflecting water pH,more » were obtained. These images show non-uniform pH in individual pores and pore clusters, with average pH levels gradually decreasing with time. Further analysis on selected pores and pore clusters shows that (1) rate-limited mass transfer prevails with slowly decreasing pH over time when the scCO 2-water interface area is low with respect to the volume of water-filled pores and pore clusters, (2) fast scCO 2 dissolution and phase equilibrium occurs when scCO 2 bubbles invade into water-filled pores, significantly enhancing the area-to-volume ratio, and (3) a transition from rate-limited to diffusion-limited mass transfer occurs in a single pore when a medium area-to-volume ratio is prevalent. The analysis also shows that two fundamental processes – scCO 2 dissolution at phase interfaces and diffusion of dsCO 2 at the pore scale (10–100 µm) observed after scCO 2 bubble invasion into water-filled pores without pore throat constraints – are relatively fast. The overall slow dissolution of scCO 2 in the millimeter-scale micromodel can be attributed to the small area-to-volume ratios that represent pore-throat configurations and characteristics of phase interfaces. Finally, this finding is applicable for the behavior of dissolution at pore, core, and field scales when water-filled pores and pore clusters of varying size are surrounded by scCO 2 at narrow pore throats.« less

Pore-scale supercritical CO 2 dissolution and mass transfer under drainage conditions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chang, Chun; Zhou, Quanlin; Oostrom, Mart

Recently, both core- and pore-scale imbibition experiments have shown non-equilibrium dissolution of supercritical CO 2 (scCO 2) and a prolonged depletion of residual scCO 2. In this paper, pore-scale scCO 2 dissolution and mass transfer under drainage conditions were investigated using a two-dimensional heterogeneous micromodel and a novel fluorescent water dye with a sensitive pH range between 3.7 and 6.5. Drainage experiments were conducted at 9 MPa and 40 °C by injecting scCO 2 into the sandstone-analogue pore network initially saturated by water without dissolved CO 2 (dsCO 2). During the experiments, time-lapse images of dye intensity, reflecting water pH,more » were obtained. These images show non-uniform pH in individual pores and pore clusters, with average pH levels gradually decreasing with time. Further analysis on selected pores and pore clusters shows that (1) rate-limited mass transfer prevails with slowly decreasing pH over time when the scCO 2-water interface area is low with respect to the volume of water-filled pores and pore clusters, (2) fast scCO 2 dissolution and phase equilibrium occurs when scCO 2 bubbles invade into water-filled pores, significantly enhancing the area-to-volume ratio, and (3) a transition from rate-limited to diffusion-limited mass transfer occurs in a single pore when a medium area-to-volume ratio is prevalent. The analysis also shows that two fundamental processes – scCO 2 dissolution at phase interfaces and diffusion of dsCO 2 at the pore scale (10–100 µm) observed after scCO 2 bubble invasion into water-filled pores without pore throat constraints – are relatively fast. The overall slow dissolution of scCO 2 in the millimeter-scale micromodel can be attributed to the small area-to-volume ratios that represent pore-throat configurations and characteristics of phase interfaces. Finally, this finding is applicable for the behavior of dissolution at pore, core, and field scales when water-filled pores and pore clusters of varying size are surrounded by scCO 2 at narrow pore throats.« less

Pore-scale supercritical CO 2 dissolution and mass transfer under drainage conditions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chang, Chun; Zhou, Quanlin; Oostrom, Mart

Abstract: Recently, both core- and pore-scale imbibition experiments have shown non-equilibrium dissolution of supercritical CO 2 (scCO 2) and a prolonged depletion of residual scCO 2. In this study, pore-scale scCO 2 dissolution and mass transfer under drainage conditions were investigated using a two-dimensional heterogeneous micromodel and a novel fluorescent water dye with a sensitive pH range between 3.7 and 6.5. Drainage experiments were conducted at 9 MPa and 40 °C by injecting scCO 2 into the sandstone-analogue pore network initially saturated by water without dissolved CO 2 (dsCO 2). During the experiments, time-lapse images of dye intensity, reflecting watermore » pH, were obtained. These images show non-uniform pH in individual pores and pore clusters, with average pH levels gradually decreasing with time. Further analysis on selected pores and pore clusters shows that (1) rate-limited mass transfer prevails with slowly decreasing pH over time when the scCO 2-water interface area is low with respect to the volume of water-filled pores and pore clusters, (2) fast scCO 2 dissolution and phase equilibrium occurs when scCO 2 bubbles invade into water-filled pores, significantly enhancing the area-to-volume ratio, and (3) a transition from rate-limited to diffusion-limited mass transfer occurs in a single pore when a medium area-to-volume ratio is prevalent. The analysis also shows that two fundamental processes – scCO 2 dissolution at phase interfaces and diffusion of dsCO 2 at the pore scale (10-100 µm) observed after scCO 2 bubble invasion into water-filled pores without pore throat constraints – are relatively fast. The overall slow dissolution of scCO 2 in the millimeter-scale micromodel can be attributed to the small area-to-volume ratios that represent pore-throat configurations and characteristics of phase interfaces. This finding is applicable for the behavior of dissolution at pore, core, and field scales when water-filled pores and pore clusters of varying size are surrounded by scCO 2 at narrow pore throats.« less

ISD3: a particokinetic model for predicting the combined effects of particle sedimentation, diffusion and dissolution on cellular dosimetry for in vitro systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thomas, Dennis G.; Smith, Jordan N.; Thrall, Brian D.

The development of particokinetic models describing the delivery of insoluble or poorly soluble nanoparticles to cells in liquid cell culture systems has improved the basis for dose-response analysis, hazard ranking from high-throughput systems, and now allows for translation of exposures across in vitro and in vivo test systems. Complimentary particokinetic models that address processes controlling delivery of both particles and released ions to cells, and the influence of particle size changes from dissolution on particle delivery for cell-culture systems would help advance our understanding of the role of particles ion dosimetry on cellular toxicology. We developed ISD3, an extension ofmore » our previously published model for insoluble particles, by deriving a specific formulation of the Population Balance Equation for soluble particles. ISD3 describes the time, concentration and particle size dependent dissolution of particles, their delivery to cells, and the delivery and uptake of ions to cells in in vitro liquid test systems. The model is modular, and can be adapted by application of any empirical model of dissolution, alternative approaches to calculating sedimentation rates, and cellular uptake or treatment of boundary conditions. We apply the model to calculate the particle and ion dosimetry of nanosilver and silver ions in vitro after calibration of two empirical models, one for particle dissolution and one for ion uptake. The results demonstrate utility and accuracy of the ISD3 framework for dosimetry in these systems. Total media ion concentration, particle concentration and total cell-associated silver time-courses were well described by the model, across 2 concentrations of 20 and 110 nm particles. ISD3 was calibrated to dissolution data for 20 nm particles as a function of serum protein concentration, but successfully described the media and cell dosimetry time-course for both particles at all concentrations and time points. We also report the finding that protein content in media has effects both on the initial rate of dissolution and the resulting near-steady state ion concentration in solution.« less

Size and performance of anoxic limestone drains to neutralize acdic mine drainagei

USGS Publications Warehouse

Cravotta, C.A.

2003-01-01

Acidic mine drainage (AMD) can be neutralized effectively in underground, anoxic limestone drains (ALDs). Owing to reaction between the AMD and limestone (CaCO3), the pH and concentrations of alkalinity and calcium increase asymptotically with detention time in the ALD, while concentrations of sulfate, ferrous iron, and manganese typically are unaffected. This paper introduces a method to predict the alkalinity produced within an ALD and to estimate the mass of limestone required for its construction on the basis of data from short-term, closed-container (cubitainer) tests. The cubitainer tests, which used an initial mass of 4 kg crushed limestone completely inundated with 2.8 L AMD, were conducted for 11 to 16 d and provided estimates for the initial and maximum alkalinities and corresponding rates of alkalinity production and limestone dissolution. Long-term (5-11 yr) data for alkalinity and CaCO3 flux at the Howe Bridge, Morrison, and Buck Mountain ALDs in Pennsylvania, USA, indicate that rates of alkalinity production and limestone dissolution under field conditions were comparable with those in cubitainers filled with limestone and AMD from each site. The alkalinity of effluent and intermediate samples along the flow path through the ALDs and long-term trends in the residual mass of limestone and the effluent alkalinity were estimated as a function of the computed detention time within the ALD and second-order dissolution rate models for cubitainer tests. Thus, cubitainer tests can be a useful tool for designing ALDs and predicting their performance.

Testing Mechanisms of Mercury Retention in GFD Products

DOE Office of Scientific and Technical Information (OSTI.GOV)

Beatty, W.L.; Schroeder, K.T.; Kairies, C.L.

2007-07-01

The natural mode of retention of Hg in FGD products is a key issue in the utilization of coal byproducts as environmentally acceptable resources. This is being investigated with a sequential extraction scheme that subjects FGD material to a series of phase-targeted reagents. Mineral phases with the greatest affinity for Hg and the form in which Hg is naturally immobilized can be discovered by observing the amount of Hg mobilized by each successive extracting solution. The extraction procedure consists of a prolonged water rinse in a continuously stirred tank extractor to dissolve CaSO4 followed by a series of batch extractions.more » These extraction include: a water rinse of the resulting residue to remove any remaining water soluble and loosely sorbed ions, 0.11M acetic acid to target carbonate minerals and exchangeable ions, 0.1 M hydroxylamine hydrochloride to dissolve manganese oxides and hydroxides, 0.25 M hydroxylamine hydrochloride in 0.25 M HCl to dissolve iron oxides and hydroxides, and hydrogen peroxide and 0.1 M ammonium acetate to oxidize organic matter and dissolve sulfide minerals. Analysis of the supernatant after each extraction step includes ICP-OES or ICP-MS for major and trace elemental composition and CVAF for mercury. Initial results indicate that Hg is associated with two distinct fractions of FGD materials. Although most of the solubilized Hg is extracted by the iron oxide and hydroxide dissolution reagent, ICP analysis suggests an association with clay minerals present in this fraction. The organic matter and sulfide minerals fraction typically yields lower but still significant amounts of Hg.« less

Reductive reactivity of iron(III) oxides in the east china sea sediments: characterization by selective extraction and kinetic dissolution.

PubMed

Chen, Liang-Jin; Zhu, Mao-Xu; Yang, Gui-Peng; Huang, Xiang-Li

2013-01-01

Reactive Fe(III) oxides in gravity-core sediments collected from the East China Sea inner shelf were quantified by using three selective extractions (acidic hydroxylamine, acidic oxalate, bicarbonate-citrate buffered sodium dithionite). Also the reactivity of Fe(III) oxides in the sediments was characterized by kinetic dissolution using ascorbic acid as reductant at pH 3.0 and 7.5 in combination with the reactive continuum model. Three parameters derived from the kinetic method: m 0 (theoretical initial amount of ascorbate-reducible Fe(III) oxides), k' (rate constant) and γ (heterogeneity of reactivity), enable a quantitative characterization of Fe(III) oxide reactivity in a standardized way. Amorphous Fe(III) oxides quantified by acidic hydroxylamine extraction were quickly consumed in the uppermost layer during early diagenesis but were not depleted over the upper 100 cm depth. The total amounts of amorphous and poorly crystalline Fe(III) oxides are highly available for efficient buffering of dissolved sulfide. As indicated by the m 0, k' and γ, the surface sediments always have the maximum content, reactivity and heterogeneity of reactive Fe(III) oxides, while the three parameters simultaneously downcore decrease, much more quickly in the upper layer than at depth. Albeit being within a small range (within one order of magnitude) of the initial rates among sediments at different depths, incongruent dissolution could result in huge discrepancies of the later dissolution rates due to differentiating heterogeneity, which cannot be revealed by selective extraction. A strong linear correlation of the m 0 at pH 3.0 with the dithionite-extractable Fe(III) suggests that the m 0 may represent Fe(III) oxide assemblages spanning amorphous and crystalline Fe(III) oxides. Maximum microbially available Fe(III) predicted by the m 0 at pH 7.5 may include both amorphous and a fraction of other less reactive Fe(III) phases.

Reductive Reactivity of Iron(III) Oxides in the East China Sea Sediments: Characterization by Selective Extraction and Kinetic Dissolution

PubMed Central

Chen, Liang-Jin; Zhu, Mao-Xu; Yang, Gui-Peng; Huang, Xiang-Li

2013-01-01

Reactive Fe(III) oxides in gravity-core sediments collected from the East China Sea inner shelf were quantified by using three selective extractions (acidic hydroxylamine, acidic oxalate, bicarbonate-citrate buffered sodium dithionite). Also the reactivity of Fe(III) oxides in the sediments was characterized by kinetic dissolution using ascorbic acid as reductant at pH 3.0 and 7.5 in combination with the reactive continuum model. Three parameters derived from the kinetic method: m 0 (theoretical initial amount of ascorbate-reducible Fe(III) oxides), k′ (rate constant) and γ (heterogeneity of reactivity), enable a quantitative characterization of Fe(III) oxide reactivity in a standardized way. Amorphous Fe(III) oxides quantified by acidic hydroxylamine extraction were quickly consumed in the uppermost layer during early diagenesis but were not depleted over the upper 100 cm depth. The total amounts of amorphous and poorly crystalline Fe(III) oxides are highly available for efficient buffering of dissolved sulfide. As indicated by the m 0, k′ and γ, the surface sediments always have the maximum content, reactivity and heterogeneity of reactive Fe(III) oxides, while the three parameters simultaneously downcore decrease, much more quickly in the upper layer than at depth. Albeit being within a small range (within one order of magnitude) of the initial rates among sediments at different depths, incongruent dissolution could result in huge discrepancies of the later dissolution rates due to differentiating heterogeneity, which cannot be revealed by selective extraction. A strong linear correlation of the m 0 at pH 3.0 with the dithionite-extractable Fe(III) suggests that the m 0 may represent Fe(III) oxide assemblages spanning amorphous and crystalline Fe(III) oxides. Maximum microbially available Fe(III) predicted by the m 0 at pH 7.5 may include both amorphous and a fraction of other less reactive Fe(III) phases. PMID:24260377

30 CFR 937.764 - Process for designating areas unsuitable for surface coal mining operations.

Code of Federal Regulations, 2013 CFR

2013-07-01

... Mining Operations, pertaining to petitioning, initial processing, hearing requirements, decisions, data base and inventory systems, public information, and rith the February 26, 1980, May 16, 1980, and...