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Sample records for selectively oxidized coals

  1. Mild pyrolysis of selectively oxidized coals

    SciTech Connect

    Hippo, E.J.

    1991-01-01

    The primary objective of this study is to investigate the removal organic sulfur from selectively oxidized Illinois coals using mild thermal/chemical processes. Work completed this quarter includes the investigation of the mild pyrolysis of unoxidized coals plus a selection of selectively oxidized coals. In addition the effect of particle size and extent of oxidation on pyrolysis was investigated. Some preliminary data concerning pyrolysis under vacuum and ambient pressure was also obtained. Work completed this quarter supports the following conclusions: (1) Desulfurization of unoxidized coals increases with increasing pyrolysis temperature and correlates with the loss of volatile matter. (2) Particle size did not influence the extent of desulfurization significantly. (3) Removing pyrite prior to pyrolysis helps to achieve a lower sulfur product beyond that expected from the removal of pyrite alone. (4) The extent of selective oxidation in teh pretreatment step did not effect the level of desulfurization obtained by pyrolysis alone. However this factor was important in the desulfurization obtained with supercritical methanol (SCM)/base. (5) Up to 84% of the sulfur has been removed from the IBC 101 coal by combining selective oxidation and SCM/base reactions. (6) Evidence for regressive reactions between volatilized sulfur compounds and partially desulfurized products was obtained by studying how changes in pyrolysis pressure effected the product sulfur content.

  2. Mild pyrolysis of selectively oxidized coals. Technical report, September 1--November 30, 1991

    SciTech Connect

    Hippo, E.J.

    1991-12-31

    The primary objective of this study is to investigate the removal organic sulfur from selectively oxidized Illinois coals using mild thermal/chemical processes. Work completed this quarter includes the investigation of the mild pyrolysis of unoxidized coals plus a selection of selectively oxidized coals. In addition the effect of particle size and extent of oxidation on pyrolysis was investigated. Some preliminary data concerning pyrolysis under vacuum and ambient pressure was also obtained. Work completed this quarter supports the following conclusions: (1) Desulfurization of unoxidized coals increases with increasing pyrolysis temperature and correlates with the loss of volatile matter. (2) Particle size did not influence the extent of desulfurization significantly. (3) Removing pyrite prior to pyrolysis helps to achieve a lower sulfur product beyond that expected from the removal of pyrite alone. (4) The extent of selective oxidation in teh pretreatment step did not effect the level of desulfurization obtained by pyrolysis alone. However this factor was important in the desulfurization obtained with supercritical methanol (SCM)/base. (5) Up to 84% of the sulfur has been removed from the IBC 101 coal by combining selective oxidation and SCM/base reactions. (6) Evidence for regressive reactions between volatilized sulfur compounds and partially desulfurized products was obtained by studying how changes in pyrolysis pressure effected the product sulfur content.

  3. MERCURY OXIDATION PROMOTED BY A SELECTIVE CATALYTIC REDUCTION CATALYST UNDER SIMULATED POWDER RIVER BASIN COAL COMBUSTION CONDITIONS

    EPA Science Inventory

    A bench-scale reactor consisting of a natural gas burner and an electrically heated reactor housing a selective catalytic reduction (SCR) catalyst was constructed for studying elemental mercury oxidation under SCR conditions. A low sulfur Power River Basin (PRB) coal combustion ...

  4. A predictive mechanism for mercury oxidation on selective catalytic reduction catalysts under coal-derived flue gas

    SciTech Connect

    Stephen Niksa; Naoki Fujiwara

    2005-12-15

    This paper introduces a predictive mechanism for elemental mercury (Hg{sup 0}) oxidation on selective catalytic reduction (SCR) catalysts in coal-fired utility gas cleaning systems, given the ammonia (NH{sub 3})/nitric oxide (NO) ratio and concentrations of Hg{sup 0} and HCl at the monolith inlet, the monolith pitch and channel shape, and the SCR temperature and space velocity. A simple premise connects the established mechanism for catalytic NO reduction to the Hg{sup 0} oxidation behavior on SCRs: that hydrochloric acid (HCl) competes for surface sites with NH{sub 3} and that Hg{sup 0} contacts these chlorinated sites either from the gas phase or as a weakly adsorbed species. This mechanism explicitly accounts for the inhibition of Hg{sup 0} oxidation by NH{sub 3}, so that the monolith sustains two chemically distinct regions. In the inlet region, strong NH{sub 3} adsorption minimizes the coverage of chlorinated surface sites, so NO reduction inhibits Hg{sup 0} oxidation. But once NH{sub 3} has been consumed, the Hg{sup 0} oxidation rate rapidly accelerates, even while the HCl concentration in the gas phase is uniform. Factors that shorten the length of the NO reduction region factors that enhance surface chlorination, promote Hg{sup 0} oxidation. This mechanism accurately interprets the reported tendencies for greater extents of Hg{sup 0} oxidation on honeycomb monoliths with smaller channel pitches and hotter temperatures and the tendency for lower extents of Hg{sup 0} oxidation for hotter temperatures on plate monoliths. The mechanism reproduces the reported extents of Hg{sup 0} oxidation on a single catalyst for four coals that generated HCl concentrations from 8 to 241 ppm, which covers the entire range encountered in the U.S. utility industry. Similar performance is also demonstrated for full-scale SCRs with diverse coal types and operating conditions. 28 refs., 5 figs., 3 tabs.

  5. Mercury oxidation promoted by a selective catalytic reduction catalyst under simulated Powder River Basin coal combustion conditions.

    PubMed

    Lee, Chun W; Serre, Shannon D; Zhao, Yongxin; Lee, Sung Jun; Hastings, Thomas W

    2008-04-01

    A bench-scale reactor consisting of a natural gas burner and an electrically heated reactor housing a selective catalytic reduction (SCR) catalyst was constructed for studying elemental mercury (Hg(o)) oxidation under SCR conditions. A low sulfur Powder River Basin (PRB) subbituminous coal combustion fly ash was injected into the entrained-flow reactor along with sulfur dioxide (SO2), nitrogen oxides (NOx), hydrogen chloride (HCl), and trace Hg(o). Concentrations of Hg(o) and total mercury (Hg) upstream and downstream of the SCR catalyst were measured using a Hg monitor. The effects of HCl concentration, SCR operating temperature, catalyst space velocity, and feed rate of PRB fly ash on Hg(o) oxidation were evaluated. It was observed that HCl provides the source of chlorine for Hg(o) oxidation under simulated PRB coal-fired SCR conditions. The decrease in Hg mass balance closure across the catalyst with decreasing HCl concentration suggests that transient Hg capture on the SCR catalyst occurred during the short test exposure periods and that the outlet speciation observed may not be representative of steady-state operation at longer exposure times. Increasing the space velocity and operating temperature of the SCR led to less Hg(o) oxidized. Introduction of PRB coal fly ash resulted in slightly decreased outlet oxidized mercury (Hg2+) as a percentage of total inlet Hg and correspondingly resulted in an incremental increase in Hg capture. The injection of ammonia (NH3) for NOx reduction by SCR was found to have a strong effect to decrease Hg oxidation. The observations suggest that Hg(o) oxidation may occur near the exit region of commercial SCR reactors. Passage of flue gas through SCR systems without NH3 injection, such as during the low-ozone season, may also impact Hg speciation and capture in the flue gas.

  6. A predictive mechanism for mercury oxidation on selective catalytic reduction catalysts under coal-derived flue gas.

    PubMed

    Niksa, Stephen; Fujiwara, Naoki

    2005-12-01

    This paper introduces a predictive mechanism for elemental mercury (Hg(o)) oxidation on selective catalytic reduction (SCR) catalysts in coal-fired utility gas cleaning systems, given the ammonia (NH3)/nitric oxide (NO) ratio and concentrations of Hg(o) and HCl at the monolith inlet, the monolith pitch and channel shape, and the SCR temperature and space velocity. A simple premise connects the established mechanism for catalytic NO reduction to the Hg(o) oxidation behavior on SCRs: that hydrochloric acid (HCl) competes for surface sites with NH3 and that Hg(o) contacts these chlorinated sites either from the gas phase or as a weakly adsorbed species. This mechanism explicitly accounts for the inhibition of Hg(o) oxidation by NH3, so that the monolith sustains two chemically distinct regions. In the inlet region, strong NH3 adsorption minimizes the coverage of chlorinated surface sites, so NO reduction inhibits Hg(o) oxidation. But once NH3 has been consumed, the Hg(o) oxidation rate rapidly accelerates, even while the HCl concentration in the gas phase is uniform. Factors that shorten the length of the NO reduction region, such as smaller channel pitches and converting from square to circular channels, and factors that enhance surface chlorination, such as higher inlet HCl concentrations and lower NH3/NO ratios, promote Hg(o) oxidation. This mechanism accurately interprets the reported tendencies for greater extents of Hg(o) oxidation on honeycomb monoliths with smaller channel pitches and hotter temperatures and the tendency for lower extents of Hg(o) oxidation for hotter temperatures on plate monoliths. The mechanism also depicts the inhibition of Hg(o) oxidation by NH3 for NH3/NO ratios from zero to 0.9. Perhaps most important for practical applications, the mechanism reproduces the reported extents of Hg(o) oxidation on a single catalyst for four coals that generated HCl concentrations from 8 to 241 ppm, which covers the entire range encountered in the U

  7. Selective Catalytic Oxidation of Hydrogen Sulfide to Elemental Sulfur from Coal-Derived Fuel Gases

    SciTech Connect

    Gardner, Todd H.; Berry, David A.; Lyons, K. David; Beer, Stephen K.; Monahan, Michael J.

    2001-11-06

    The development of low cost, highly efficient, desulfurization technology with integrated sulfur recovery remains a principle barrier issue for Vision 21 integrated gasification combined cycle (IGCC) power generation plants. In this plan, the U. S. Department of Energy will construct ultra-clean, modular, co-production IGCC power plants each with chemical products tailored to meet the demands of specific regional markets. The catalysts employed in these co-production modules, for example water-gas-shift and Fischer-Tropsch catalysts, are readily poisoned by hydrogen sulfide (H{sub 2}S), a sulfur contaminant, present in the coal-derived fuel gases. To prevent poisoning of these catalysts, the removal of H{sub 2}S down to the parts-per-billion level is necessary. Historically, research into the purification of coal-derived fuel gases has focused on dry technologies that offer the prospect of higher combined cycle efficiencies as well as improved thermal integration with co-production modules. Primarily, these concepts rely on a highly selective process separation step to remove low concentrations of H{sub 2}S present in the fuel gases and produce a concentrated stream of sulfur bearing effluent. This effluent must then undergo further processing to be converted to its final form, usually elemental sulfur. Ultimately, desulfurization of coal-derived fuel gases may cost as much as 15% of the total fixed capital investment (Chen et al., 1992). It is, therefore, desirable to develop new technology that can accomplish H{sub 2}S separation and direct conversion to elemental sulfur more efficiently and with a lower initial fixed capital investment.

  8. Mechanisms for selective coalescence of coals

    SciTech Connect

    Wheelock, T.D.; Markuszewski, R.; Fan, C.W.; Drzymala, J.; Allen, R.W.; Hu, Y.C.; Tyson, D.; Xiaoping, Qiu; Lessa, A.

    1988-12-01

    The study of basic mechanisms which underlie various processes for cleaning coal by selective agglomeration with oil was continued. Upper Freeport coal, used extensively in this study, was further characterized by measuring its heat of wetting in dilute salt solutions (CaCl{sub 2}/NaCl/FeCl{sub 3}) range of pH. The effect of mild surface oxidation on the agglomeration characteristics of Lower Kittanning coal was investigated because of the large pyritic sulfur content of this material. Oxidation was performed by exposing a thin layer of the finely ground coal to air at room temperature for 10 days. When the ground material was subsequently agglomerated with heptane, the agglomeration recovery of the oxidized coal was only slightly less than that of unoxidized coal. However, the sulfur content was lower than that of agglomerated coal which had not been oxidized. The effect of pyrite surface properties on the separation of coal/pyrite mixtures was further studied by combining acid-cleaned mineral pyrite with No. 2 gas seam coal from Raleigh Country, West Virginia. The separation was not as good as that obtained previously with mixtures involving mineral pyrite which had been mildly oxidized. 1 ref., 12 figs., 3 tabs.

  9. The cyclic oxidation resistance at 1200 C of beta-NiAl, FeAl, and CoAl alloys with selected third element additions

    NASA Technical Reports Server (NTRS)

    Barrett, C. A.; Titran, R. H.

    1992-01-01

    The intermetallic compounds Beta-NiAl, FeAl, and CoAl were tested in cyclic oxidation with selected third element alloy additions. Tests in static air for 200 1-hr cycles at 1200 C indicated by specific weight change/time data and x-ray diffraction analysis that the 5 at percent alloy additions did not significantly improve the oxidation resistance over the alumina forming baseline alloys without the additions. Many of the alloy additions were actually deleterious. Ta and Nb were the only alloy additions that actually altered the nature of the oxide(s) formed and still maintained the oxidation resistance of the protective alumina scale.

  10. Impacts of halogen additions on mercury oxidation, in a slipstream selective catalyst reduction (SCR), reactor when burning sub-bituminous coal

    SciTech Connect

    Yan Cao; Zhengyang Gao; Jiashun Zhu; Quanhai Wang; Yaji Huang; Chengchung Chiu; Bruce Parker; Paul Chu; Wei-ping Pan

    2008-01-01

    This paper presents a comparison of impacts of halogen species on the elemental mercury (Hg(0)) oxidation in a real coal-derived flue gas atmosphere. It is reported there is a higher percentage of Hg(0) in the flue gas when burning sub-bituminous coal (herein Powder River Basin (PRB) coal) and lignite, even with the use of selective catalytic reduction (SCR). The higher Hg(0) concentration in the flue gas makes it difficult to use the wet-FGD process for the mercury emission control in coal-fired utility boilers. Investigation of enhanced Hg(0) oxidation by addition of hydrogen halogens (HF, HCl, HBr, and HI) was conducted in a slipstream reactor with and without SCR catalysts when burning PRB coal. Two commercial SCR catalysts were evaluated. SCR catalyst no. 1 showed higher efficiencies of both NO reduction and Hg(0) oxidation than those of SCR catalyst no. 2. NH{sub 3} addition seemed to inhibit the Hg(0) oxidation, which indicated competitive processes between NH{sub 3} reduction and Hg(0) oxidation on the surface of SCR catalysts. The hydrogen halogens, in the order of impact on Hg(0) oxidation, were HBr, HI, and HCl or HF. Addition of HBr at approximately 3 ppm could achieve 80% Hg(0) oxidation. Addition of HI at approximately 5 ppm could achieve 40% Hg(0) oxidation. In comparison to the empty reactor, 40% Hg(0) oxidation could be achieved when HCl addition was up to 300 ppm. The enhanced Hg(0) oxidation by addition of HBr and HI seemed not to be correlated to the catalytic effects by both evaluated SCR catalysts. The effectiveness of conversion of hydrogen halogens to halogen molecules or interhalogens seemed to be attributed to their impacts on Hg(0) oxidation. 30 refs., 4 figs.

  11. Impacts of halogen additions on mercury oxidation, in a slipstream selective catalyst reduction (SCR), reactor when burning sub-bituminous coal.

    PubMed

    Cao, Yan; Gao, Zhengyang; Zhu, Jiashun; Wang, Quanhai; Huang, Yaji; Chiu, Chengchung; Parker, Bruce; Chu, Paul; Pant, Wei-Ping

    2008-01-01

    This paper presents a comparison of impacts of halogen species on the elemental mercury (Hg(0)) oxidation in a real coal-derived flue gas atmosphere. It is reported there is a higher percentage of Hg(0) in the flue gas when burning sub-bituminous coal (herein Powder River Basin (PRB) coal) and lignite, even with the use of selective catalytic reduction (SCR). The higher Hg(0)concentration in the flue gas makes it difficult to use the wet-FGD process for the mercury emission control in coal-fired utility boilers. Investigation of enhanced Hg(0) oxidation by addition of hydrogen halogens (HF, HCl, HBr, and HI) was conducted in a slipstream reactor with and without SCR catalysts when burning PRB coal. Two commercial SCR catalysts were evaluated. SCR catalyst no. 1 showed higher efficiencies of both NO reduction and Hg(0) oxidation than those of SCR catalyst no. 2. NH3 addition seemed to inhibit the Hg(0) oxidation, which indicated competitive processes between NH3 reduction and Hg(0) oxidation on the surface of SCR catalysts. The hydrogen halogens, in the order of impact on Hg(0) oxidation, were HBr, HI, and HCl or HF. Addition of HBr at approximately 3 ppm could achieve 80% Hg(0) oxidation. Addition of HI at approximately 5 ppm could achieve 40% Hg(0) oxidation. In comparison to the empty reactor, 40% Hg(0) oxidation could be achieved when HCl addition was up to 300 ppm. The enhanced Hg(0) oxidation by addition of HBr and HI seemed not to be correlated to the catalytic effects by both evaluated SCR catalysts. The effectiveness of conversion of hydrogen halogens to halogen molecules or interhalogens seemed to be attributed to their impacts on Hg(0) oxidation.

  12. Plasma gasification of coal in different oxidants

    SciTech Connect

    Matveev, I.B.; Messerle, V.E.; Ustimenko, A.B.

    2008-12-15

    Oxidant selection is the highest priority for advanced coal gasification-process development. This paper presents comparative analysis of the Powder River Basin bituminous-coal gasification processes for entrained-flow plasma gasifier. Several oxidants, which might be employed for perspective commercial applications, have been chosen, including air, steam/carbon-dioxide blend, carbon dioxide, steam, steam/air, steam/oxygen, and oxygen. Synthesis gas composition, carbon gasification degree, specific power consumptions, and power efficiency for these processes were determined. The influence of the selected oxidant composition on the gasification-process main characteristics have been investigated.

  13. REFORMULATION OF COAL-DERIVED TRANSPORTATION FUELS: SELECTIVE OXIDATION OF CARBON MONOXIDE ON METAL FOAM CATALYSTS

    SciTech Connect

    Paul Chin; George W. Roberts; James J. Spivey

    2003-12-31

    Uses for structured catalytic supports, such as ceramic straight-channel monoliths and ceramic foams, have been established for a long time. One of the most prominent examples is the washcoated ceramic monolith as a three-way catalytic converter for gasoline-powered automobiles. A distinct alternative to the ceramic monolith is the metal foam, with potential use in fuel cell-powered automobiles. The metal foams are characterized by their pores per inch (ppi) and density ({rho}). In previous research, using 5 wt% platinum (Pt) and 0.5 wt% iron (Fe) catalysts, washcoated metal foams, 5.08 cm in length and 2.54 cm in diameter, of both varying and similar ppi and {rho} were tested for their activity (X{sub CO}) and selectivity (S{sub CO}) on a CO preferential oxidation (PROX) reaction in the presence of a H{sub 2}-rich gas stream. The variances in these metal foams' activity and selectivity were much larger than expected. Other structured supports with 5 wt% Pt, 0-1 wt% Fe weight loading were also examined. A theory for this phenomenon states that even though these structured supports have a similar nominal catalyst weight loading, only a certain percentage of the Pt/Fe catalyst is exposed on the surface as an active site for CO adsorption. We will use two techniques, pulse chemisorption and temperature programmed desorption (TPD), to characterize our structured supports. Active metal count, metal dispersion, and other calculations will help clarify the causes for the activity and selectivity variations between the supports. Results on ceramic monoliths show that a higher Fe loading yields a lower dispersion, potentially because of Fe inhibition of the Pt surface for CO adsorption. This theory is used to explain the reason for activity and selectivity differences for varying ppi and {rho} metal foams; less active and selective metal foams have a lower Fe loading, which justifies their higher metal dispersion. Data on the CO desorption temperature and average metal

  14. Demonstration of selective catalytic reduction (SCR) technology for the control of nitrogen oxide (NOx) emissions from high-sulfur coal-fired boilers

    SciTech Connect

    Not Available

    1991-11-01

    The objective of this project is to demonstrate and evaluate commercially available Selective Catalytic Reduction (SCR) catalysts from US, Japanese and European catalyst suppliers on a high-sulfur US coal-fired boiler. SCR is a post-combustion nitrogen oxide (NO{sub x}) control technology that involves injecting ammonia into the flue gas generated from coal combustion in an electric utility boiler. The flue gas containing ammonia is then passed through a reactor that contains a specialized catalyst. In the presence of the catalyst, the ammonia reacts with NO{sub x} to convert it to nitrogen and water vapor.

  15. Thermal oxidative stability of coal-based JP-900 jet fuel: Impact on selected physical properties

    NASA Astrophysics Data System (ADS)

    Berkhous, Scott K.

    The low-temperature oxidative stability of a fuel is determined by the potential for production of peroxides, leading to the formation of oxygenated products, change in color, and ultimately formation of sediment. The role of oxygenated products in determining the low-temperature physical properties of jet fuels has not been reported in the literature. The current study evaluates the impact of oxidative jet fuel stability on the following low-temperature properties: crystal size, crystal shape, freeze point, and viscosity. It was found that over the range of oxidative conditions studied, compositionally similar products were produced for each fuel. Increasing the reaction temperature, between 50°C and 200°C, and pressure, between atmospheric and 200 psi, altered the quantity of oxidation products, but did not significantly shift the composition of these products. Major products observed in the oxidation of jet fuel samples included alcohols, ketones, and to a lesser extent acids. The predominant crystal structures observed using cold-stage microscope techniques were small needle-like structures for cycloalkane-based fuels and large broad leaf-shaped structures for n-alkane-based fuels. The presence of oxidized compounds in the fuel samples decreased the overall size of the crystals and produced ribbon-shaped crystals in the n -alkane-based fuels. This was the result of the oxygenated functionalities of the polar compounds interrupting the regular alignment of molecules in the crystal structure. Major differences in the freeze points of oxidized and unoxidized fuel samples were not observed. However, the viscosities of the oxidized fuel samples were found to be higher at all temperatures than the unoxidized fuel samples. The model of Coutinho et al. was found to be effective for predicting the freeze point of n-alkane-rich fuels, but failed to accurately predict the freeze point of cycloalkane-based hydrocarbons. A model by Cookson et al. was found to be effective

  16. Quality of Selected Hungarian Coals

    USGS Publications Warehouse

    Landis, E.R.; Rohrbacher, T.J.; Gluskoter, H.J.; Fodor, B.; Gombar, G.

    2007-01-01

    As part of a program conducted jointly by the U.S. Geological Survey and the Hungarian Geological Survey under the auspices of the United States-Hungarian Science and Technology Fund, a total of 39 samples from five coal mines in Hungary were selected for analysis. The mine areas sampled represent most of the coal mined recently in Hungary. Almost all the coal is used to generate electricity. Coals from the five mines (four underground, one surface) reflect differences in age, depositional setting, organic and inorganic components of the original sediments, and deformational history. Classified according to the ranking system of the American Society for Testing and Materials, the coals range in rank from lignite B (Pliocene[?] coals) to high volatile A bituminous (Jurassic coals). With respect to grade classification, based on seam-weighted averages of moisture, ash, and sulfur contents: (1) all contain high moisture (more than 10 percent), (2) all except the Eocene coals are high (more than 15 percent) in ash yield, and (3) two (Jurassic and Eocene coals) are high in sulfur (more than 3 percent) and three (Cretaceous, Miocene, and Pliocene coals) have medium sulfur contents (1 to 3 percent). Average heat values range from 4,000 to 8,650 British thermal units per pound.

  17. Demonstration of selective catalytic reduction (SCR) technology for the control of nitrogen oxide (NO sub x ) emissions from high-sulfur coal-fired boilers

    SciTech Connect

    Not Available

    1991-08-01

    The objective of this project is to demonstrate and evaluate commercially available Selective Catalytic Reduction (SCR) catalysts from US, Japanese and European catalyst suppliers on a high-sulfur US coal-fired boiler. SCR is a post-combustion nitrogen oxide (NOx) control technology that involves injecting ammonia into the flue gas generated from coal combustion in an electric utility boiler. The flue gas containing ammonia is then passed through a reactor that contains a specialized catalyst. In the presence of the catalyst, the ammonia reacts with NOx to convert it to nitrogen and water vapor, Although SCR is widely practiced in Japan and Europe, there are numerous technical uncertainties associated with applying SCR to US coals. These uncertainties include: (1) potential catalyst deactivation due to poisoning by trace metal species present in US coals that are not present in other fuel performance of the technology and effects on the balance-of-plant equipment in the presence of high amounts of SO{sub 2} and SO{sub 3}. (3) performance of a wide variety of SCR catalyst compositions, geometries and methods of manufacture under typical high-sulfur coal-fired utility operating conditions. These uncertainties will be explored by constructing a series of small-scale SCR reactors and simultaneously exposing different SCR catalysts to flue gas derived from the combustion of high sulfur US coal.

  18. REFORMULATION OF COAL-DERIVED TRANSPORTATION FUELS: SELECTIVE OXIDATION OF CARBON MONOXIDE ON METAL FOAM CATALYSTS

    SciTech Connect

    Paul Chin; Xiaolei Sun; George W. Roberts; Amornmart Sirijarhuphan; Sourabh Pansare; James G. Goodwin Jr; Richard W. Rice; James J. Spivey

    2005-06-01

    Hydrocarbon fuels must be reformed in a series of steps to provide hydrogen for use in proton exchange membrane fuel cells (PEMFCs). Preferential oxidation (PROX) is one method to reduce the CO concentration to less than 10 ppm in the presence of {approx}40% H{sub 2}, CO{sub 2}, and steam. This will prevent CO poisoning of the PEMFC anode. Structured supports, such as ceramic monoliths, can be used for the PROX reaction. Alternatively, metal foams offer a number of advantages over the traditional ceramic monolith.

  19. Coal combustion by wet oxidation

    SciTech Connect

    Bettinger, J.A.; Lamparter, R.A.; McDowell, D.C.

    1980-11-15

    The combustion of coal by wet oxidation was studied by the Center for Waste Management Programs, of Michigan Technological University. In wet oxidation a combustible material, such as coal, is reacted with oxygen in the presence of liquid water. The reaction is typically carried out in the range of 204/sup 0/C (400/sup 0/F) to 353/sup 0/C (650/sup 0/F) with sufficient pressure to maintain the water present in the liquid state, and provide the partial pressure of oxygen in the gas phase necessary to carry out the reaction. Experimental studies to explore the key reaction parameters of temperature, time, oxidant, catalyst, coal type, and mesh size were conducted by running batch tests in a one-gallon stirred autoclave. The factors exhibiting the greatest effect on the extent of reaction were temperature and residence time. The effect of temperature was studied from 204/sup 0/C (400/sup 0/F) to 260/sup 0/C (500/sup 0/F) with a residence time from 600 to 3600 seconds. From this data, the reaction activation energy of 2.7 x 10/sup 4/ calories per mole was determined for a high-volatile-A-Bituminous type coal. The reaction rate constant may be determined at any temperature from the activation energy using the Arrhenius equation. Additional data were generated on the effect of mesh size and different coal types. A sample of peat was also tested. Two catalysts were evaluated, and their effects on reaction rate presented in the report. In addition to the high temperature combustion, low temperature desulfurization is discussed. Desulfurization can improve low grade coal to be used in conventional combustion methods. It was found that 90% of the sulfur can be removed from the coal by wet oxidation with the carbon untouched. Further desulfurization studies are indicated.

  20. Innovative clean coal technology (ICCT): Demonstration of selective catalytic reduction (SCR) technology for the control of nitrogen oxide (NO{sub x}) emissions from high-sulfur coal-fired boilers. Fourth quarterly progress report

    SciTech Connect

    1992-12-31

    The objective of this project is to demonstrate and evaluate commercially available Selective Catalytic Reduction (SCR) catalysts from US, Japanese and European catalyst suppliers on a high-sulfur US coal-fired boiler. SCR is a post-combustion nitrogen oxide (NO{sub x}) control technology that involves injecting ammonia into the flue gas generated from coal combustion in an electric utility boiler. The flue gas containing ammonia is then passed through a reactor that contains a specialized catalyst. In the presence of the catalyst, the ammonia reacts with NO{sub x} to convert it to nitrogen and water vapor. Although SCR is widely practiced in Japan and Europe, there are numerous technical uncertainties include: (1) potential catalyst deactivation due to poisoning by trace metal species present in US coals that are not present in other fuels; (2) performance of the technology and effects on the balance-of-plant equipment in the presence of high amounts of SO{sub 2} and SO{sub 3}; and (3) performance of a wide variety of SCR catalyst compositions, geometries and methods of manufacture under typical high-sulfur coal-fired utility operating conditions. These uncertainties will be explored by constructing a series of small-scale SCR reactors and simultaneously exposing different SCR catalysts to flue gas derived from the combustion of high sulfur US coal.

  1. Innovative Clean Coal Technology (ICCT). Demonstration of Selective Catalytic Reduction (SCR) technology for the control of nitrogen oxide (NO{sub x}) emissions from high-sulfur coal-fired boilers: Volume 1. Final report

    SciTech Connect

    1996-10-01

    The objective of this project is to demonstrate and evaluate commercially available Selective Catalytic Reduction (SCR) catalysts from U.S., Japanese and European catalyst suppliers on a high-sulfur U.S. coal-fired boiler. SCR is a post-combustion nitrogen oxide (NO.) control technology that involves injecting ammonia into the flue gas generated from coal combustion in an electric utility boiler. The flue gas containing ammonia is then passed through a reactor that contains a specialized catalyst. In the presence of the catalyst, the ammonia reacts with NO. to convert it to nitrogen and water vapor. Although SCR is widely practiced in Japan and Europe on gas-, oil-, and low-sulfur coal- fired boilers, there are several technical uncertainties associated with applying SCR to U.S. coals. These uncertainties include: 1) potential catalyst deactivation due to poisoning by trace metal species present in U.S. coals that are not present in other fuels. 2) performance of the technology and effects on the balance-of- plant equipment in the presence of high amounts of SO{sub 2} and SO{sub 3}. 3) performance of a wide variety of SCR catalyst compositions, geometries and methods of manufacturer under typical high-sulfur coal-fired utility operating conditions. These uncertainties were explored by operating nine small-scale SCR reactors and simultaneously exposing different SCR catalysts to flue gas derived from the combustion of high sulfur U.S. coal. In addition, the test facility operating experience provided a basis for an economic study investigating the implementation of SCR technology.

  2. Innovative Clean Coal Technology (ICCT): Demonstration of selective catalytic reduction (SCR) technology for the control of nitrogen oxide (NO{sub x}) emissions from high-sulfur coal-fired boilers. Technical progress report, October 1993--December 1993

    SciTech Connect

    1995-06-01

    The objective of this project is to demonstrate and evaluate commercially available Selective Catalytic Reduction (SCR) catalysts from U.S., Japanese and European catalyst suppliers on a high-sulfur U.S. coal-fired boiler. SCR is a post-combustion nitrogen oxide (NO{sub x}) control technology that involves injecting ammonia into the flue gas generated from coal combustion in an electric utility boiler. The flue gas containing ammonia is then passed through a reactor that contains a specialized catalyst. In the presence of the catalyst, the ammonia reacts with NO{sub x} to convert it to nitrogen and water vapor. Although SCR is widely practiced in Japan and Europe on gas-, oil-, and low-sulfur coal-fired boilers, there are several technical uncertainties associated with applying SCR to U.S. coals. These uncertainties include: (1) potential catalyst deactivation due to poisoning by trace metal species present in U.S. coals that are not present in other fuels; (2) performance of the technology and effects on the balance-of-plant equipment in the presence of high amounts of SO{sub 2} and SO{sub 3}; and (3) performance of a wide variety of SCR catalyst compositions, geometries and methods of manufacture under typical high-sulfur coal-fired utility operating conditions. These uncertainties are being explored by operating a series of small-scale SCR reactors and simultaneously exposing different SCR catalysts to flue gas derived from the combustion of high sulfur U.S. coal.

  3. Oxidative Denitrogenation of Coal Liquids

    NASA Astrophysics Data System (ADS)

    Mirshamsi, Sepideh

    The oxidative denitrogenation of quinoline (as a model compound representing the nitrogen containing structure of coal liquids) has been investigated in two steps: oxidation by perdecanoic acid at 50 °C to produce quinoline N-oxide in order to weaken the nitrogen-carbon bond; thermal decomposition of quinoline N-oxide to remove nitrogen as its respective oxides. Quinoline is successfully converted to quinoline N-oxide in the oxidation step. Thermal decomposition of quinoline N-oxide at 400 °C and 600 kPa of N2 produces 52-wt% quinoline, 22-wt% a condensed polymeric compound and 26-wt% gaseous mixture of CO2, CO and O2. Almost all the nitrogen content of quinoline N-oxide has remained in the residue of decomposition reaction. This confirms that thermal decomposition not only fails to remove nitrogen from structure of the oxidized molecule, but it also leads to production of a more complex aromatic structure with 10.4-wt% nitrogen content, compared to 10.6-wt% nitrogen content of quinoline.

  4. Process for coal liquefaction employing selective coal feed

    DOEpatents

    Hoover, David S.; Givens, Edwin N.

    1983-01-01

    An improved coal liquefaction process is provided whereby coal conversion is improved and yields of pentane soluble liquefaction products are increased. In this process, selected feed coal is pulverized and slurried with a process derived solvent, passed through a preheater and one or more dissolvers in the presence of hydrogen-rich gases at elevated temperatures and pressures, following which solids, including mineral ash and unconverted coal macerals, are separated from the condensed reactor effluent. The selected feed coals comprise washed coals having a substantial amount of mineral matter, preferably from about 25-75%, by weight, based upon run-of-mine coal, removed with at least 1.0% by weight of pyritic sulfur remaining and exhibiting vitrinite reflectance of less than about 0.70%.

  5. Selective flotation of inorganic sulfides from coal

    DOEpatents

    Miller, K.J.; Wen, Wu-Wey

    1988-05-31

    Pyritic sulfur is removed from coal or other carbonaceous material through the use of humic acid as a coal flotation depressant. Following the removal of coarse pyrite, the carbonaceous material is blended with humic acid, a pyrite flotation collector and a frothing agent within a flotation cell to selectively float pyritic sulfur leaving clean coal as an underflow. 1 fig., 2 tabs.

  6. Selective flotation of inorganic sulfides from coal

    DOEpatents

    Miller, Kenneth J.; Wen, Wu-Wey

    1989-01-01

    Pyritic sulfur is removed from coal or other carbonaceous material through the use of humic acid as a coal flotation depressant. Following the removal of coarse pyrite, the carbonaceous material is blended with humic acid, a pyrite flotation collector and a frothing agent within a flotation cell to selectively float pyritic sulfur leaving clean coal as an underflow.

  7. Flotation and flocculation chemistry of coal and oxidized coals

    SciTech Connect

    Somasundaran, P.

    1990-01-01

    The objective of this research project is to understand the fundamentals involved in the flotation and flocculation of coal and oxidized coals and elucidate mechanisms by which surface interactions between coal and various reagents enhance coal beneficiation. An understanding of the nature of the heterogeneity of coal surfaces arising from the intrinsic distribution of chemical moieties is fundamental to the elucidation of mechanism of coal surface modification and its role in interfacial processes such as flotation, flocculation and agglomeration. A new approach for determining the distribution in surface properties of coal particles was developed in this study and various techniques capable of providing such information were identified. Distributions in surface energy, contact angle and wettability were obtained using novel techniques such as centrifugal immersion and film flotation. Changes in these distributions upon oxidation and surface modifications were monitored and discussed. An approach to the modelling of coal surface site distributions based on thermodynamic information obtained from gas adsorption and immersion calorimetry is proposed. Polyacrylamide and dodecane was used to alter the coal surface. Methanol adsorption was also studied. 62 figs.

  8. Coal combustion by wet oxidation. Wet oxidation of coal for energy production: test plan and partial results. Interim report

    SciTech Connect

    Bettinger, J.A.

    1980-07-10

    A test plan has been developed which will provide the data necessary to carry out design and economic studies of a steam generating facility, employing the wet oxidation of coal as a heat source. It is obvious, from the literature search and preliminary testing, that the higher the reaction temperature, the more complete the combustion of coal. However, operation at elevated temperatures and pressures present difficult design problems, and the necessary equipment is costly. Operation under these conditions can only be justified by the higher economic value of high pressure and temperature steam. With a reduction in temperature from 550/sup 0/F (228/sup 0/C) to 450/sup 0/F (232/sup 0/C), the operating pressure is reduced by more than half, thus holding down the overall cost of the system. For this reason, our plan is to study both the enhancement of low temperature wet oxidation of coal, and the higher operating regions. The coal selected for the first portion of this test is an Eastern Appalachian high-volatile-A Bituminous type, from the Upper Clarion seam in Pennsylvania. This coal was selected as being a typical high sulfur, eastern coal. The wet oxidation of coal to produce low pressure steam is a process suited for a high sulfur, low grade, coal. It is not intended that wet oxidation be used in all applications with all types of coals, as it does not appear to be competitive, economically, with conventional combustion, therefore the testing will focus on using high sulfur, low grade coals. In the later portion of testing all the available coals will be tested. In addition, a sample of Minnesota peat will be tested to determine if it also can be used in the process.

  9. Innovative clean coal technology (ICCT): Demonstration of Selective Catalytic Reduction (SCR) technology for the control of nitrogen oxide (NO sub x ) emissions from high-sulfur coal-fired boilers

    SciTech Connect

    Not Available

    1990-11-01

    This project's objective is to demonstrate the selective catalytic reduction (SCR) process that removes nitrogen oxides (NOx) from the flue gas of boilers that burn US high-sulfur coal. The SCR technology involves the catalytic reduction of NH{sub 3} which is injected into the flue gas to react with NOx contained in the flue gas to produce molecular nitrogen (N{sub 2}) and water vapor. This quarter, work was initiated on the pilot plant ductwork layout, flue gas distribution and flow control concepts and preliminary pilot plant reactor designs concepts. Conceptual designs were produced for flue gas flow distribution and control philosophy that includes a variable speed fan, dampers, full-flow venturi and reactor bypass ducting to ensure proper control and distribution among all the reactors. 23 figs., 16 tabs.

  10. MOLECULAR ACCESSIBILITY IN OXIDIZED AND DRIED COALS

    SciTech Connect

    Lowell D. Kispert

    1999-07-01

    Changes in physical and chemical structure of the micropore system in eight solvent swelled Argonne Premium Coal Sample (APCS) coals upon weathering were studied using the EPR spin probe method. Spin probes, which are allowed to diffuse into the coal structure during swelling, are trapped when the swelling solvent is removed. Excess spin probes are removed from the coal surface and larger pores so that only the presence of spin probes trapped in pores which closely approximate the size of the spin probe are detected. Detailed explanations and illustrations of the experimental procedure used are given. Careful examination of the weathering process on coal as a function of rank was accomplished using the EPR spin probe method. The retention of spin probes in eight APCS coals provided valuable insight into both the loss of water and the oxidation which occur during the weathering process. The results could be explained in terms of the autoxidation process observed in other polymeric systems. It was shown that initial oxidation of coal can result in increased cross-linking in the coal structure. As the oxidation process continued, both the covalent and hydrogen bonded character of the coal were significantly altered. The retention character of some coals during oxidation was shown to change by as much as three orders of magnitude. Experiments were performed to study the effects of short term oxidation and dehydration on coal structure by exposing the coal samples to argon or oxygen for time periods up to five minutes. The results indicate that the structure of coal is extremely sensitive to environmental changes and exhibits significant changes in as little as 30 seconds. Exposure of Illinois No.6 coal to argon or oxygen for 30 seconds caused a decrease in the retention of polar spin probes by as much as an order of magnitude. The studies presented here suggest that the structure of coal is dynamic in nature, and has an intimate relationship with the nature of its

  11. Molecular accessibility in oxidized and dried coals. Quarterly report

    SciTech Connect

    Kispert, L.D.

    1996-09-01

    The objective of this research project is to determine the molecular and structural changes that occur in swelled coal as a result of oxidation and moisture loss both in the presence and absence of light using the EPR spin pore method. The proposed study will make it possible to deduce the molecular accessibility distribution in swelled, oxidized APCS coal as a function of sunlight for each rank as a function of (1) size (up to 6 nm) and shape, (2) the relative acidic/basic reactive site distribution, and (3) the role of hydrogen bonding as a function of swelling solvents. The advantage of the EPR method is that it permits molecules of selected shape, size and chemical reactivity to be used as probes of molecular accessible regions of swelled coal. From such data an optimum catalyst can be designed to convert oxidized coal into a more convenient form and methods can be devised to lessen the detrimental weathering processes.

  12. Molecular accessibility in oxidized and dried coals. Quarterly report

    SciTech Connect

    Kispert, L.D.

    1995-06-01

    The objective of this research project is to determine the molecular and structural changes that occur in swelled coal as a result of oxidation and moisture loss both in the presence and absence of light using the newly developed EPR spin probe method. The proposed study will make it possible to deduce the molecular accessibility distribution in swelled, oxidized APCS coal for each rank as a function of (1) size (up to 6 nm) and shape, (2) the relative acidic/basic reactive site distributions, and (3) the role of hydrogen bonding as a function of swelling solvents. The advantage of the EPR method is that it permits molecules of selected shape, size and chemical reactivity to be used as probes of molecular accessible regions of swelled coal. From such data an optimum catalyst can be designed to convert oxidized coal into a more convenient form and methods can be devised to lessen the detrimental weathering processes.

  13. Demonstration of selective catalytic reduction (SCR) technology for the control of nitrogen oxide (NOx) emissions from high-sulfur coal-fired boilers. Quarterly report No. 5, July--September 1991

    SciTech Connect

    Not Available

    1991-11-01

    The objective of this project is to demonstrate and evaluate commercially available Selective Catalytic Reduction (SCR) catalysts from US, Japanese and European catalyst suppliers on a high-sulfur US coal-fired boiler. SCR is a post-combustion nitrogen oxide (NO{sub x}) control technology that involves injecting ammonia into the flue gas generated from coal combustion in an electric utility boiler. The flue gas containing ammonia is then passed through a reactor that contains a specialized catalyst. In the presence of the catalyst, the ammonia reacts with NO{sub x} to convert it to nitrogen and water vapor.

  14. Oxidation of coal and coal pyrite mechanisms and influence on surface characteristics. [Coal pyrite electrodes

    SciTech Connect

    Doyle, F.M.

    1992-01-01

    The objective of this research is to develop a mechanistic understanding of the oxidation of coal and coal pyrite, and to correlate the intrinsic physical and chemical properties of these minerals, along with changes resulting from oxidation, with those surface properties that influence the behavior in physical cleaning processes. The results will provide fundamental insight into oxidation, in terms of the bulk and surface chemistry, the microstructure, and the semiconductor properties of the pyrite. During the eighth quarter, wet chemical and dry oxidation tests were done on Upper Freeport coal from the Troutville [number sign]2 Mine, Clearfield County, Pennsylvania. In addition electrochemical experiments were done on electrodes prepared from Upper Freeport coal pyrite and Pittsburgh coal pyrite samples provided by the US Bureau of Mines, Pittsburgh Research Center, Pennsylvania.

  15. ENHANCED COAL REBURNING IN OXIDIZING ENVIRONMENTS

    SciTech Connect

    Eric G. Eddings; Kerry Kelly; Dana W. Overacker; Christopher R. Thurston

    2004-11-01

    Conventional fuel rich coal reburning relies upon two primary mechanisms: (1) the reaction of coal volatiles with NO to form HCN, which can subsequently decay to molecular nitrogen (N{sub 2}) given sufficient residence time at a suitable temperature; and (2), additional NO reduction by reaction of NO with carbon on the coal char surfaces. Recent research has indicated the possibility of HCN release as an additional product during char oxidation, and under appropriate conditions this HCN could provide a third mechanism for reducing NO to N{sub 2}. Lab-scale experiments and kinetic calculations were carried out to identify conditions that might lead to effective coal reburning under oxidizing conditions. The results of the kinetic calculations indicated that, depending on the temperature, oxygen concentrations in the range of 200 ppm to 1000 ppm (0.1%) would provide the greatest levels of gas phase reduction of NO using HCN, and that reductions between 60-80% are possible (in the absence of heterogeneous effects). Experiments using pulverized coal in a laminar flow drop tube furnace demonstrated NO reduction levels as high as 40-50%; however, these experiments were shown to have limited gas/coal contacting. The two different experimental configurations used demonstrated a clear dependence of observed NO reduction efficiency on gas/coal loading. The laboratory results were thus extrapolated to gas/solid loadings more typical of a utility boiler, and this extrapolation indicated that greater levels of NO reductions may well be achievable in a coal-fired boiler application. It was concluded that, given a knowledge of the location of high NO concentrations (obtained for example by CFD modeling), these regions could be targeted with coal injection under slightly oxidizing conditions to obtain NO reductions in excess of the 40-50% levels obtained in the lab-scale experiments. It is recommended that further testing under conventional pulverized coal combustion conditions be

  16. Demonstration of selective catalytic reduction (SCR) technology for the control of nitrogen oxide (NO{sub x}) emissions from high-sulfur coal-fired boilers. Quarterly report No. 4, April--June 1991

    SciTech Connect

    Not Available

    1991-08-01

    The objective of this project is to demonstrate and evaluate commercially available Selective Catalytic Reduction (SCR) catalysts from US, Japanese and European catalyst suppliers on a high-sulfur US coal-fired boiler. SCR is a post-combustion nitrogen oxide (NOx) control technology that involves injecting ammonia into the flue gas generated from coal combustion in an electric utility boiler. The flue gas containing ammonia is then passed through a reactor that contains a specialized catalyst. In the presence of the catalyst, the ammonia reacts with NOx to convert it to nitrogen and water vapor, Although SCR is widely practiced in Japan and Europe, there are numerous technical uncertainties associated with applying SCR to US coals. These uncertainties include: (1) potential catalyst deactivation due to poisoning by trace metal species present in US coals that are not present in other fuel performance of the technology and effects on the balance-of-plant equipment in the presence of high amounts of SO{sub 2} and SO{sub 3}. (3) performance of a wide variety of SCR catalyst compositions, geometries and methods of manufacture under typical high-sulfur coal-fired utility operating conditions. These uncertainties will be explored by constructing a series of small-scale SCR reactors and simultaneously exposing different SCR catalysts to flue gas derived from the combustion of high sulfur US coal.

  17. Fluidized bed selective pyrolysis of coal

    DOEpatents

    Shang, J.Y.; Cha, C.Y.; Merriam, N.W.

    1992-12-15

    The present invention discloses a process for the pyrolysis of coal which comprises the effective utilization of two zonal inclined fluidized beds, where said zones can be selectively controlled as to temperature and heating rate. The first zonal inclined fluidized bed serves as a dryer for crushed coal and additionally is controlled to selectively pyrolyze said coal producing substantially carbon dioxide for recycle use. The second zonal inclined fluidized bed further pyrolyses the coal to gaseous, liquid and char products under controlled temperature and heating rate zones designed to economically integrate the product mix. The gas and liquid products are recovered from the gaseous effluent stream while the char which remains can be further treated or utilized in a subsequent process step. 9 figs.

  18. Fluidized bed selective pyrolysis of coal

    DOEpatents

    Shang, Jer Y.; Cha, Chang Y.; Merriam, Norman W.

    1992-01-01

    The present invention discloses a process for the pyrolysis of coal which comprises the effective utilization of two zonal inclined fluidized beds, where said zones can be selectively controlled as to temperature and heating rate. The first zonal inclined fluidized bed serves as a dryer for crushed coal and additionally is controlled to selectively pyrolyze said coal producing substantially carbon dioxide for recycle use. The second zonal inclined fluidized bed further pyrolyzes the coal to gaseous, liquid and char products under controlled temperature and heating rate zones designed to economically integrate the product mix. The gas and liquid products are recovered from the gaseous effluent stream while the char which remains can be further treated or utilized in a subsequent process step.

  19. Oxidation of coal and coal pyrite mechanisms and influence on surface characteristics

    SciTech Connect

    Doyle, F.M.

    1992-06-30

    during the seventh quarter, electrokinetic, humic acid extraction and film flotation tests were done on oxidized samples of Upper Freeport coal from the Troutville {number sign} 2 Mine, Clearfield County, Pennsylvania. Scanning electron microscopy and energy dispersive X-ray analysis was done to characterize the morphology and composition of the surface of as-received coal, oxidized coal, oxidized coal after extraction of humic acids and humic acid extracted from oxidized coal. In addition, electrochemical studies were done on electrodes prepared from coal pyrite samples.

  20. Oxidation of coal and coal pyrite mechanisms and influence on surface characteristics

    SciTech Connect

    Doyle, F.M.

    1992-01-01

    During the ninth quarter, electrochemical experiments were done on electrodes prepared from Upper Freeport coal pyrite and Pittsburgh coal pyrite samples provided by the US Bureau of Mines, Pittsburgh Research Center, Pennsylvania. Scanning electron microscopy and energy dispersive X-ray analysis were done to characterize the morphology and composition of the surface of as-received coal, oxidized coal and coal pyrite. In addition, electrokinetic tests were done on Upper Freeport coal pyrite.

  1. Mechanisms for selective agglomeration of coals

    SciTech Connect

    Wheelock, T.D.; Drzymala, J.; Allen, R.W.; Hu, Y.-C.; Tyson, D.; Xiaoping, Qiu; Lessa, A.

    1989-05-01

    Work continued on the basic mechanisms which underlie various processes for beneficiating aqueous suspensions of coal by selective agglomeration with oil. A new method was demonstrated for characterizing the agglomerability of coal suspensions. This method utilizes a photometric dispersion analyzer to monitor changes in the turbidity of a particle suspension as increasing amounts of oil are added to the suspension in a batch agglomeration test. Agglomeration of the particles leads to a marked decrease in the turbidity of the suspension. Another experimental technique was also demonstrated for characterizing oil agglomeration. This technique involves measuring the rate of growth of agglomerates in a continuous flow system operating under stead-state conditions. The data are analyzed by means of a population balance. The results of a preliminary set of experiments in which Indiana V seam coal was agglomerated with tetralin seemed to fit a particular growth model very well. Equipment was also constructed for studying the kinetics of agglomeration in a batch process. While earlier work showed that quebracho (a commercially available dispersant) is a strong agglomeration depressant for pyrite, recent experiments with mixtures of Upper Freeport coal and mineral pyrite showed that quebracho does not appear to be sufficiently selective. Further consideration was given to the separation of mixtures of coal and pyrite agglomeration with heptane. 2 refs., 17 figs., 1 tab.

  2. COST OF SELECTIVE CATALYTIC REDUCTION (SCR) APPLICATION FOR NOX CONTROL ON COAL-FIRED BOILERS

    EPA Science Inventory

    The report provides a methodology for estimating budgetary costs associated with retrofit applications of selective catalytic reduction (SCR) technology on coal-fired boilers. SCR is a postcombustion nitrogen oxides (NOx) control technology capable of providing NOx reductions >90...

  3. Detection and modeling of subsurface coal oxidation

    USGS Publications Warehouse

    Leonhart, Leo S.; Rasmussen, William O.; Barringer, Anthony R.

    1980-01-01

    The oxidation and sustained ignition of coal and coaly wastes within surface coal mine spoils in the southwestern U.S. have hampered the success of reclamation efforts at these locations. To assess better the magnitude, depth, geometry, and dynamics of the oxidation process thermal infrared remote sensing data have been used. Digital thermal imagery was found to be useful for this purpose and was integrated with finite different heat transfer models to yield predictions of several characteristics of the thermal source. In addition to thermal infrared imagery, aerial color and false color infrared imagery were found to provide useful information for the interpretation of oxidation phenomena by means of variations in surface vegetation, color of the surface material, subsidence, etc. The combined use of thermal infrared imagery and thermal modeling techniques are well suited for use in exploration and interpretation of other thermal targets.

  4. Bacterial Oxidation of Pyritic Materials in Coal.

    PubMed

    Silverman, M P; Rogoff, M H; Wender, I

    1961-11-01

    Applicability of the manometric method for studying the oxidation of pyritic material in the presence of bacteria has been demonstrated. Resting cells of Ferrobacillus ferrooxidans accelerated the oxidation of coal pyrites and coarsely crystalline marcasite, but were inactive on coarsely crystalline pyrite. Resting cells of Thiobacillus thiooxidans were inactive on all pyrites tested. Oxidation rates in the presence of Ferrobacillus were increased by reducing the particle size of pyritic samples, and, in one case, by removing the CaCO(3) from a calcite-containing sample. PMID:16349610

  5. Bacterial Oxidation of Pyritic Materials in Coal.

    PubMed

    Silverman, M P; Rogoff, M H; Wender, I

    1961-11-01

    Applicability of the manometric method for studying the oxidation of pyritic material in the presence of bacteria has been demonstrated. Resting cells of Ferrobacillus ferrooxidans accelerated the oxidation of coal pyrites and coarsely crystalline marcasite, but were inactive on coarsely crystalline pyrite. Resting cells of Thiobacillus thiooxidans were inactive on all pyrites tested. Oxidation rates in the presence of Ferrobacillus were increased by reducing the particle size of pyritic samples, and, in one case, by removing the CaCO(3) from a calcite-containing sample.

  6. Upgrading of coal liquefaction feedstock by selective agglomeration

    SciTech Connect

    Lai, R.; Sinha, K.; Richardson, A.; Killmeyer, R.; Utz, B.; Hickey, R.; Cillo, D.

    1994-03-01

    The technical feasibility study of using selective agglomeration (with coal-derived oil) to upgrade Illinois No. 6 coal for a liquefaction feedstock was completed. Effects of coal particle size, slurry pH, oil-to-coal ratio, and operating temperature on mineral matter reduction, clean coal weight recovery, and clean coal moisture content were studied. The addition of coal-derived naphtha or kerosene as conditioners to increase hydrophobicity and recovery of coal was also investigated. Results showed that approximately 70% of the mineral matter could be removed from this coal at a clean coal weight recovery of over 85% by grinding the coal to a mean volume diameter of about 10 microns and properly selecting of the operation variables.

  7. Oxidation of Mercury in Products of Coal Combustion

    SciTech Connect

    Peter Walsh; Giang Tong; Neeles Bhopatkar; Thomas Gale; George Blankenship; Conrad Ingram; Selasi Blavo Tesfamariam Mehreteab; Victor Banjoko; Yohannes Ghirmazion; Heng Ban; April Sibley

    2009-09-14

    Laboratory measurements of mercury oxidation during selective catalytic reduction (SCR) of nitric oxide, simulation of pilot-scale measurements of mercury oxidation and adsorption by unburned carbon and fly ash, and synthesis of new materials for simultaneous oxidation and adsorption of mercury, were performed in support of the development of technology for control of mercury emissions from coal-fired boilers and furnaces. Conversion of gas-phase mercury from the elemental state to water-soluble oxidized form (HgCl{sub 2}) enables removal of mercury during wet flue gas desulfurization. The increase in mercury oxidation in a monolithic V{sub 2}O{sub 5}-WO{sub 3}/TiO{sub 2} SCR catalyst with increasing HCl at low levels of HCl (< 10 ppmv) and decrease in mercury oxidation with increasing NH{sub 3}/NO ratio during SCR were consistent with results of previous work by others. The most significant finding of the present work was the inhibition of mercury oxidation in the presence of CO during SCR of NO at low levels of HCl. In the presence of 2 ppmv HCl, expected in combustion products from some Powder River Basin coals, an increase in CO from 0 to 50 ppmv reduced the extent of mercury oxidation from 24 {+-} 3 to 1 {+-} 4%. Further increase in CO to 100 ppmv completely suppressed mercury oxidation. In the presence of 11-12 ppmv HCl, increasing CO from 0 to {approx}120 ppmv reduced mercury oxidation from {approx}70% to 50%. Conversion of SO{sub 2} to sulfate also decreased with increasing NH{sub 3}/NO ratio, but the effects of HCl and CO in flue gas on SO{sub 2} oxidation were unclear. Oxidation and adsorption of mercury by unburned carbon and fly ash enables mercury removal in a particulate control device. A chemical kinetic mechanism consisting of nine homogeneous and heterogeneous reactions for mercury oxidation and removal was developed to interpret pilot-scale measurements of mercury oxidation and adsorption by unburned carbon and fly ash in experiments at pilot

  8. Further studies of the effects of oxidation on the surface properties of coal and coal pyrite

    SciTech Connect

    Herrera, M.N.

    1994-12-31

    The objective of this research was to investigate the oxidation behavior of coal and coal pyrite and to correlate the changes in the surface properties induced by oxidation, along with the intrinsic physical and chemical properties of these organic and inorganic materials, with the behavior in physical coal cleaning processes. This provide more fundamental knowledge for understanding the way in which different factors interact in a medium as heterogeneous as coal. Fourteen coal samples of different ranks ranging from high to medium sulfur content were studied by dry oxidation tests at different temperatures and humidities, and by wet oxidation tests using different oxidizing agents. The concentration of surface oxygen functional groups was determined by ion-exchange methods. The changes in the coal composition with oxidation were analyzed by spectroscopic techniques. The wettability of as-received and oxidized coal and coal pyrite samples was assessed by film flotation tests. The electrokinetic behavior of different coals and coal pyrite samples was studied by electrokinetic tests using electrophoresis. Possible oxidation mechanisms have been proposed to explain the changes on the coal surface induced by different oxidation treatments.

  9. Enhanced coal hydrogasification via oxidative pretreatment

    SciTech Connect

    Miller, D.J.

    1992-04-16

    The gasification of coal char by hydrogen is much slower than in steam or carbon dioxide; moreover, hydrogasification rate in pure hydrogen decreases sharply with conversion for most carbons. To overcome this kinetic behavior, the oxidation of the char prior to and during hydrogasification has been investigated as a means of enhancing hydro gasification rate. Kinetic rate studies under well-characterized conditions have been complemented by careful surface analyses to characterize oxygen on the char surface prior to and during hydrogasification.

  10. Microbial oxidation of pyrrhotites in coal chars

    USGS Publications Warehouse

    Miller, K.W.; Risatti, J.B.

    1988-01-01

    The ability of Thiobacillus ferrooxidans to oxidize pyrrhotite minerals occurring in coal chars was investigated, to evaluate the feasibility of microbial char desulphurization. Bio-oxidation of pyrrhotites in chars produced by two different processes was demonstrated conclusively. Microbial removal of sulphur from a char and its parent coal proceeded at the rate of 3.5% and 12% day-1, respectively with a total of 48% and 81% removal after 27 days. The pH of shake flask cultures containing the coal dropped naturally to a final value of 2.2, while the pH of cultures containing the corresponding char rose and had to be lowered artificially with additional acid. Amending char cultures with elemental sulphur to increase acidity upon bio-oxidation and prevent precipitation of ferric iron was successful; however, the extent of pyrrhotite removal, as demonstated by X-ray diffraction analysis, was not improved. As yet, there is no explanation for the failure of microbial removal of pyrrhotitic sulphur to go to completion. ?? 1988.

  11. Fast and Selective Preconcentration of Europium from Wastewater and Coal Soil by Graphene Oxide/Silane@Fe3O4 Dendritic Nanostructure.

    PubMed

    Patra, Santanu; Roy, Ekta; Madhuri, Rashmi; Sharma, Prashant K

    2015-05-19

    In this study, nanocomposite of graphene oxide and silane modified magnetic nanoparticles (silane@Fe3O4) were synthesized in a form of dendritic structure. For this, silane@Fe3O4 nanoparticle gets sandwiched between two layers of graphene oxide by chemical synthesis route. The synthesized dendritic structure was used as a monomer for synthesis of europium ion imprinted polymer. The synthesis of imprinted polymer was contemplated onto the surface of the vinyl group modified silica fiber by activated generated free radical atom-transfer radical polymerization, that is, AGET-ATRP technique. The synthesized dendritic monomer was characterized by XRD, FT-IR, VSM, FE-SEM, and TEM analyses. The imprinted polymer modified silica fiber was first validated in the aqueous and blood samples for successful extraction and detection of europium ion with limit of detection = 0.050 pg mL(-1) (signal/noise = 3). The imprinted polymer modified silica fiber was also used for preconcentration and separation of europium metal ion from various soil samples of coal mine areas. However, the same silica fiber was also used for wastewater treatment and shows 100% performance for europium removal. The findings herein suggested that dendritic nanocomposite could be potentially used as a highly effective material for the enrichment and preconcentration of europium or other trivalent lanthanides/actinides in nuclear waste management.

  12. Fast and Selective Preconcentration of Europium from Wastewater and Coal Soil by Graphene Oxide/Silane@Fe3O4 Dendritic Nanostructure.

    PubMed

    Patra, Santanu; Roy, Ekta; Madhuri, Rashmi; Sharma, Prashant K

    2015-05-19

    In this study, nanocomposite of graphene oxide and silane modified magnetic nanoparticles (silane@Fe3O4) were synthesized in a form of dendritic structure. For this, silane@Fe3O4 nanoparticle gets sandwiched between two layers of graphene oxide by chemical synthesis route. The synthesized dendritic structure was used as a monomer for synthesis of europium ion imprinted polymer. The synthesis of imprinted polymer was contemplated onto the surface of the vinyl group modified silica fiber by activated generated free radical atom-transfer radical polymerization, that is, AGET-ATRP technique. The synthesized dendritic monomer was characterized by XRD, FT-IR, VSM, FE-SEM, and TEM analyses. The imprinted polymer modified silica fiber was first validated in the aqueous and blood samples for successful extraction and detection of europium ion with limit of detection = 0.050 pg mL(-1) (signal/noise = 3). The imprinted polymer modified silica fiber was also used for preconcentration and separation of europium metal ion from various soil samples of coal mine areas. However, the same silica fiber was also used for wastewater treatment and shows 100% performance for europium removal. The findings herein suggested that dendritic nanocomposite could be potentially used as a highly effective material for the enrichment and preconcentration of europium or other trivalent lanthanides/actinides in nuclear waste management. PMID:25895010

  13. Molecular accessibility in oxidized and dried coals. Quarterly report, 1996

    SciTech Connect

    Kispert, L.D.

    1996-06-01

    The objective of this research project is to determine the molecular and structural changes that occur in swelled coal as a result of oxidation and moisture loss both in the presence and absence of light using our newly developed EPR spin probe method. The proposed study will make it possible to deduce the molecular accessibility distribution in swelled, oxidized APCS coal for each rank as a function of (1) size (up to 6 nm) and shape, (2) the relative acidic/basic reactive site distributions, and (3) the role of hydrogen bonding as a function of swelling solvents. The advantage of the EPR method is that it permits molecules of selected shape, size and chemical reactivity to be used as probes of molecular accessible regions of swelled coal. From such data an optimum catalyst can be designed to convert oxidized coal into a more convenient form and methods can be devised to lessen the detrimental weathering processes. It appears that the observed binary swelling data for the APCS coals studied to date can be explained in terms of four different processes: one, disruption of weak hydrogen bonds which protect or isolate the interconnected micropore system; two, disruption of weak hydrogen bonds which protect individual micropores; three, the competition of pyridine for the active sites capable of establishing hydrogen bonds or the `poisoning` of active sites; four, disruption of stronger hydrogen bonds within the macromolecular structure which cause an opening of the structure. The contributions of each of these factors to the spin probe retention with increasing concentrations of pyridine vary up to 5% pyridine. At concentrations above 5% pyridine, the first factor becomes less significant, and variations in the others require greater changes in pyridine concentration.

  14. A new approach in ultrapurification of coal by selective flocculation

    SciTech Connect

    Moudgil, B.M.

    1990-03-01

    The mathematical and computational model developed for predicting optimum selectivity achievable with a polymer has been successfully verified experimentally. Adsorption density of polymer SF 362 on coal and coal pyrite was measured using the depletion method. Values of {Upsilon}{sub R} (active sites ratio) and {Theta} (fractional surface coverage) were computed using the adsorption data. The mathematical model predicted a low selectivity in separating coal pyrite from coal which was also verified by selective flocculation tests. FTIR surface area and size distribution analysis indicated that mineral matter associated with both coal and coal pyrite samples can adversely affect the performance of the polymer in the selective flocculation process. Adsorption tests are in progress to identify experimental conditions (dispersant, pH, flocculent) yielding a higher value of {Upsilon}{sub R} so that the desired separation of coal pyrite from coal can be obtained. 2 refs., 8 figs., 3 tabs.

  15. Oxidation of coal and coal pyrite mechanisms and influence on surface characteristics

    SciTech Connect

    Doyle, F.M.

    1992-01-28

    The objective of this research is to develop a mechanistic understanding of the oxidation of coal and coal pyrite, and to correlate the intrinsic physical and chemical properties of these minerals, along with changes resulting from oxidation, with those surface properties that influence the behavior in physical coal cleaning processes. The results will provide fundamental insight into oxidation, in terms of the bulk and surface chemistry, the microstructure, and the semiconductor properties of the pyrite. During the fifth quarter, wet chemical and dry oxidation tests were done on Upper Freeport coal from the Troutville {number sign}2 Mine, Clearfield County, Pennsylvania.

  16. Treatment of aqueous streams containing strong oxidants using bituminous coal

    SciTech Connect

    Doyle, F.M.; Bodine, D.L.

    1995-12-31

    Certain oxidizing contaminants, notably Cr(VI) and Mn(VII), are attenuated by reduction and sorption on organic matter in soils. Coals have some chemical similarity with this organic matter, and might be used on an industrial scale to treat effluents. We have studied the ability of acidic KMnO{sub 4} to oxidize Upper Freeport, bituminous coal with concurrent sorption of the resulting Mn(IV) and Mn(II). The oxidizing ability of Cr(VI) was briefly investigated. The ability of the oxidized coal to sorb Cu{sup 2+} and Cd{sup 2+} was then studied, and compared with coal oxidized by hydrogen peroxide. The effect of oxidation treatment, metal ion concentration, and solution pH on metal uptake kinetics and coal loading was investigated. Potential applications for treating effluents containing oxidizing ions are discussed.

  17. Oxidative decomposition of formaldehyde catalyzed by a bituminous coal

    SciTech Connect

    Haim Cohen; Uri Green

    2009-05-15

    It has been observed that molecular hydrogen is formed during long-term storage of bituminous coals via oxidative decomposition of formaldehyde by coal surface peroxides. This study has investigated the effects of coal quantity, temperature, and water content on the molecular hydrogen formation with a typical American coal (Pittsburgh No. 6). The results indicate that the coal's surface serves as a catalyst in the formation processes of molecular hydrogen. Furthermore, the results also indicate that low temperature emission of molecular hydrogen may possibly be the cause of unexplained explosions in confined spaces containing bituminous coals, for example, underground mines or ship holds. 20 refs., 4 figs., 6 tabs.

  18. Molecular accessibility in oxidized and dried coals. Quarterly report

    SciTech Connect

    Kispert, L.D.

    1995-12-01

    The objective of this research project is to determine the molecular and structural changes that occur in swelled coal as a result of oxidation and moisture los both in the presence and absence of light using our newly developed EPR spin probe method. The proposed study will make it possible to deduce the molecular accessibility distribution swelled, {ital oxidized} APCS coal for each rank as a function of (1) size (up to 6 nm) and shape, (2) the relative acidic/basic reactive site distributions, and (3) the role of hydrogen bonding as a function of swelling solvents. The advantage of the EPR method is that it permits molecules of selected shape, size and chemical reactivity to be used as probes of molecular accessible regions of swelled coal. From such data an optimum catalyst can be designed to convert oxidized coal into a more convenient form and methods can be devised to lessen the detrimental weathering process. This quarter we have continued to examine the effect of exposure of light before alkylation versus after O-alkylation of the coal structure. The variation in uptake of spin probe VII (amine group) is depicted in figure 1 for Wyodak-Anderson. Before O-alkylation, a significant decrease occurred in the uptake of VII with increasing exposure to ambient light. This suggests that partial break-up of the hydrogen bond network occurs, making it possible to wash out more of the spin probes. This effect was eliminated if the coal was O-alkylated after exposure to sunlight (Figure 2). The removal of the source of hydrogen bonding is responsible for the lack of spin probe up-take variation with time of exposure to light. Further experiments have shown that the data in Figures 1 and 2 is reproducible with a deviation of less than {+-} 10%. It has also been observed that if Wyodak-Anderson coal is exposed to sunlight before swelling, the oscillatory up-take of spin probe VII as a function of percent pyridine is essentially removed.

  19. Molecular accessibility in oxidized and dried coals. Quarterly report, [January 1, 1996--March 31, 1996

    SciTech Connect

    Kispert, L.D.

    1996-03-01

    The objective of this research project is to determine the molecular and structural changes that occur in swelled coal as a result of oxidation and moisture loss both in the presence and absence of light using our newly developed EPR spin probe method. The proposed study will make it possible to deduce the molecular accessibility distribution in swelled, oxidized Argonne Premium Coal Samples (APCS) for each rank as a function of (1) size (up to 6nm) and shape, (2) the relative acidic/basic reactive site distributions, and (3) the role of hydrogen bonding as a function of swelling solvents. The advantage of the EPR method is that it permits molecules of selected shape, size and chemical reactivity to be used as probes of molecular accessible regions of swelled coal. From such data an optimum catalyst can be designed to convert oxidized coal into a more convenient form and methods can be devised to lessen the detrimental weathering processes. Results of current study on changes in molecular accessibility in APCS coal oxidized in presence of sunlight show that accessibility to spin probes upon O-alkylation of the oxidized coal depends on the percent oxygen present before alkylation. An increase in microporosity occurs upon alkylation and this increase is more pronounced in higher rank than lower ranked coals. It was also observed that the increase in microporosity depends on the structure of each coal.

  20. Oxidation of coal and coal pyrite mechanisms and influence on surface characteristics. Progress report

    SciTech Connect

    Doyle, F.M.

    1995-02-28

    The objective of this research is to develop a mechanistic understanding of the oxidation of coal and coal pyrite, and to correlate the intrinsic physical and chemical properties of these minerals, along with changes resulting from oxidation, with those surface properties that influence the behavior in physical cleaning processes. Work during the eighteenth quarter has focused on severe oxidation of coal by thermal and chemical treatment, and on investigating the partition of metal ions between such strongly oxidized coal samples and aqueous solutions. This partitioning behavior is being followed to obtain further information on the chemistry of the coal surfaces after different oxidation treatments, for example, whether partition occurs by an ion-exchange mechanism, or whether the surface is capable of changing the oxidation state of metallic species, with concurrent surface or bulk precipitation.

  1. Desulfurization of coal: enhanced selectivity using phase transfer catalysts. Quarterly report, March 1 - May 31, 1996

    SciTech Connect

    Palmer, S.R.; Hippo, E.J.

    1996-12-31

    Due to environmental problems related to the combustion of high sulfur Illinois coal, there continues to be interest in the development in viable pre-combustion desulfurization processes. Recent studies by the authors have obtained very good sulfur removals but the reagents that are used are too expensive. Use of cheaper reagents leads to a loss of desired coal properties. This study investigated the application phase transfer catalysts to the selective oxidation of sulfur in coal using air and oxygen as oxidants. The phase transfer catalyst is expected to function as a selectivity moderator by permitting the use of milder reaction conditions that otherwise necessary. This would enhance the sulfur selectivity and help retain the heating value of the coal. The use of certain coal combustion wastes for desulfurization, and the application of cerium (IV) catalyzed air oxidation for selective sulfur oxidation are also being studied. If successful, this project could lead to the rapid development of a commercially viable desulfurization process. This would significantly improve the marketability of Illinois coal.

  2. A new approach in ultrapurification of coal by selective flocculation

    SciTech Connect

    Moudgil, B.M.

    1992-04-01

    The specific objective of the present investigation is to develop a mathematical and computational model to elicit values of active sites ({phi}) and fractional surface coverage ({theta}) which would yield optimum separation of coal from coal pyrite and coal refuse. Attempts are to be made to select appropriate flocculants and experimental conditions to obtain {phi} and {theta} values as dictated by the theoretical model so as to achieve the desired separation in naturally occurring samples of fine coal. (VC)

  3. Coal as a catalyst in the oxidative decomposition of formaldehyde

    SciTech Connect

    Nehemia, V.; Davidi, S.; Richter, U.B.; Haenel, M.W.; Cohen, H.

    1997-12-31

    Recently it has been reported that molecular hydrogen is released in small, but appreciable concentrations as a result of the low temperature (40--120 C) oxidation of bituminous coal during long term storage. The amounts of hydrogen produced correlates linearly with the amounts of oxygen consumed. An oxidation process promoted by molecular oxygen is generally not expected to produce a reduction product such as hydrogen. It has been suggested that formaldehyde might be formed in the low temperature oxidation of the coal, and that this acts as the hydrogen precursor. Batch reactor studies have proved that formaldehyde undergoes oxidative decomposition with oxygen. The authors now propose that formaldehyde is oxidized by coal-derived hydroperoxides to form dioxirane, which subsequently decomposes into hydrogen and carbon dioxide. It is known that acetone is oxidized by potassium peroxomonosulfate (KHSO{sub 5}), ``oxone`` to dimethyldioxirane, which recently has become an important oxidant in preparative chemistry. According to a theoretical study (published in 1993) the decomposition of dioxirane yielding hydrogen and carbon dioxide is exothermic by {minus}420 kJ/mole. In order to further support their mechanistic proposal, the authors investigated the oxidative decomposition of formaldehyde by tert-butyl hydroperoxide (BuOOH) in the absence and the presence of a German bituminous coal. It is observed that indeed hydrogen and CO{sub 2} are produced in about a 1:1 ratio. A demineralized coal sample was prepared in order to investigate the influence of the mineral matter within the coal on the oxidative decomposition of formaldehyde. The results corroborate the suggestion that the hydrogen emission in the low temperature oxidation of coal originates from formaldehyde oxidation by coal-derived hydroperoxides, both of which appeared to be formed by decomposition of surface oxides within the coal.

  4. Desulfurization of coal: Enhanced selectivity using phase transfer catalysts. Technical report, September 1--November 30, 1995

    SciTech Connect

    Palmer, S.R.; Hippo, E.J.

    1995-12-31

    Due to environmental problems related to the combustion of high sulfur Illinois coal, there continues to be interest in the development of viable pre-combustion desulfurization processes. Recent studies by the authors have obtained very good sulfur removals but the reagents that are used are too expensive. Use of cheaper reagents leads to a loss of desired coal properties. This study investigates the application of phase transfer catalysts to the selective oxidation of sulfur in coal using air and oxygen as oxidants. The phase transfer catalyst is expected to function as a selectivity moderator by permitting the use of milder reaction conditions than otherwise necessary. This would enhance the sulfur selectivity and help retain the heating value of the coal. The use of certain coal combustion wastes for desulfurization, and the application of cerium (IV) catalyzed air oxidations for selective sulfur oxidation are also being studied. If successful this project could lead to the rapid development of a commercially viable desulfurization process. This would significantly improve the marketability of Illinois coal. During this quarter aliquots of the IBC-101 coal have been ground to various particle sizes in an attempt to find the optimum physical pretreatment for mineral, especially pyrite, removal. Analysis of these various aliquots shows them to be representative of the original coal. In addition, preliminary desulfurization reactions using fly ash and scrubber sludges have been performed on an unoxidized IBC-101 sample. Results will be available next quarter. Also, SEM-EDAX analysis of the fly ash indicates that it contains oxides that have shown activity in base desulfurization reactions.

  5. Selective solvent absorption in coal conversion

    SciTech Connect

    Larsen, J.W.; Lapucha, A.; Lazarov, L.; Amui, J.

    1992-04-01

    The objectives of this project are: (1) to determine the importance of the presence of added hydrogen donor compounds within the coal in the first stage of direct liquefaction processes; and (2) to determine the composition of the solvent absorbed by and present within the coal in the first stage of direct coal liquefaction.

  6. The research of ultrafine coal selective flocculation in China

    SciTech Connect

    Cai, Z.

    1994-12-31

    Selective flocculation was suggested to separate ultrafine coal which was taken from the coal preparation plants of Datun, Bayi, Dawukou etc. A number of selective flocculation separation tests have been done and the results show the method has good selectivity and can be used to separate ultrafine coal as well as to produce super-clean coal. After selective flocculation, the ash content of clean coal may reach 12--13% with the lowest of 5.73% and the recovery of combustible coal is over 90%. The ash content difference between the two products is 50% or so. By using selective flocculation to produce super-clean coal, the ash content is below 3%, both the yield and combustible recovery are about 90% and the highest is 94%, and 95.88% respectively. It is promising to use this technique in the split-feed flotation for ultrafine coal separation and to produce super-clean coal. The factors influencing selective flocculation are also discussed in the paper.

  7. Process for selective grinding of coal

    DOEpatents

    Venkatachari, Mukund K.; Benz, August D.; Huettenhain, Horst

    1991-01-01

    A process for preparing coal for use as a fuel. Forming a coal-water slurry having solid coal particles with a particle size not exceeding about 80 microns, transferring the coal-water slurry to a solid bowl centrifuge, and operating same to classify the ground coal-water slurry to provide a centrate containing solid particles with a particle size distribution of from about 5 microns to about 20 microns and a centrifuge cake of solids having a particle size distribution of from about 10 microns to about 80 microns. The classifer cake is reground and mixed with fresh feed to the solid bowl centrifuge for additional classification.

  8. Molecular accessibility in oxidized and dried coals: Quarterly report, October 1996--December 1996

    SciTech Connect

    Kispert, L.D.

    1996-12-01

    The objective of this research project is to determine the molecular and structural changes that occur in swelled coal as a result of oxidation and moisture loss both in the presence and absence of light using our EPR spin probe method. The proposed study will make it possible to deduce the molecular accessibility distribution in swelled, oxidized APCS coal as a function of sunlight for each rank as a function of (1) size (up to 6 nm) and shape, (2) the relative acidic/basic reactive site distributions, and (3) the role of hydrogen bonding as a function of swelling solvents. The advantage of the EPR method is that it permits molecules of selected shape, size and chemical reactivity to be used as probes of molecular accessible regions of swelled coal. From such data an optimum catalyst can be designed to convert oxidized coal into a more convenient form and methods can be devised to lessen the detrimental weathering processes.

  9. Molecular accessibility in oxidized and dried coals. Quarterly report, July 1995--September 1995

    SciTech Connect

    Kispert, L.D.

    1996-02-01

    The objective of this research project is to determine the molecular and structural changes that occur in swelled coal as a result of oxidation and moisture loss both in the presence and absence of light using our newly developed EPR spin probe method. The proposed study will make it possible to deduce the molecular accessibility distribution in swelled, oxidized APCS coal for each rank as a function of (1) size (up to 6 nm) and shape, (2) the relative acidic/basic reactive site distributions, and (3) the role of hydrogen bonding as a function of swelling solvents. The advantage of the EPR method is that it permits molecules of selected shape, size and chemical reactivity to be used as probes of molecular accessible regions of swelled coal. From such data an optimum catalyst can be designed to convert oxidized coal into a more convenient form and methods can be devised to lessen the detrimental weathering processes.

  10. Molecular accessibility in oxidized and dried coals. Quarterly report, January 1995--March 1995

    SciTech Connect

    Kispert, L.D.

    1995-03-01

    The objective of this research project is to determine the molecular and structural changes that occur in swelled coal as a result of oxidation and moisture loss both in the presence and absence of light using our newly developed EPR spin probe method. The proposed study will make it possible to deduce the molecular accessibility distribution in swelled, oxidized APCS coal for each rank as a function of (1) size (up to 6 nm) and shape, (2) the relative acidic/basic reactive site distributions, and (3) the role of hydrogen bonding as a function of swelling solvents. The advantage of the EPR method is that it permits molecules of selected shape, size and chemical reactivity to be used as probes of molecular accessible regions of swelled coal. From such data an optimum catalyst can be designed to convert oxidized coal into a more convenient form and methods can be devised to lessen the detrimental weathering processes.

  11. Molecular accessibility in oxidized and dried coals. Quarterly report, October--November 1994

    SciTech Connect

    Kispert, L.D.

    1994-12-01

    The objective of this research project is to determine the molecular and structural changes that occur in swelled coal as a result of oxidation and moisture loss both in the presence and absence of light using a newly developed EPR spin probe method. The proposed study will make it possible to deduce the molecular accessibility distribution in swelled, oxidized APCS coal for each rank as a function of (1) size (up to 6 nm) and shape, (2) the relative acidic/basic reactive site distributions, and (3) the role of hydrogen bonding as a function of swelling solvents. The advantage of the EPR method is that it permits molecules of selected shape, size and chemical reactivity to be used as probes of molecular accessible regions of swelled coal. From such data an optimum catalyst can be designed to convert oxidized coal into a more convenient form and methods can be devised to lessen the detrimental weathering processes.

  12. COAL CONVERSION WASTEWATER TREATMENT BY CATALYTIC OXIDATION IN SUPERCRITICAL WATER

    SciTech Connect

    Phillip E. Savage

    1999-10-18

    Wastewaters from coal-conversion processes contain phenolic compounds in appreciable concentrations. These compounds need to be removed so that the water can be discharged or re-used. Catalytic oxidation in supercritical water is one potential means of treating coal-conversion wastewaters, and this project examined the reactions of phenol over different heterogeneous oxidation catalysts in supercritical water. More specifically, we examined the oxidation of phenol over a commercial catalyst and over bulk MnO{sub 2}, bulk TiO{sub 2}, and CuO supported on Al{sub 2} O{sub 3}. We used phenol as the model pollutant because it is ubiquitous in coal-conversion wastewaters and there is a large database for non-catalytic supercritical water oxidation (SCWO) with which we can contrast results from catalytic SCWO. The overall objective of this research project is to obtain the reaction engineering information required to evaluate the utility of catalytic supercritical water oxidation for treating wastes arising from coal conversion processes. All four materials were active for catalytic supercritical water oxidation. Indeed, all four materials produced phenol conversions and CO{sub 2} yields in excess of those obtained from purely homogeneous, uncatalyzed oxidation reactions. The commercial catalyst was so active that we could not reliably measure reaction rates that were not limited by pore diffusion. Therefore, we performed experiments with bulk transition metal oxides. The bulk MnO{sub 2} and TiO{sub 2} catalysts enhance both the phenol disappearance and CO{sub 2} formation rates during SCWO. MnO{sub 2} does not affect the selectivity to CO{sub 2}, or to the phenol dimers at a given phenol conversion. However, the selectivities to CO{sub 2} are increased and the selectivities to phenol dimers are decreased in the presence of TiO{sub 2} , which are desirable trends for a catalytic SCWO process. The role of the catalyst appears to be accelerating the rate of formation of

  13. Coal conversion wastewater treatment by catalytic oxidation in supercritical water

    SciTech Connect

    Phillip E. Savage

    1999-10-20

    Wastewaters from coal-conversion processes contain phenolic compounds in appreciable concentrations. These compounds need to be removed so that the water can be discharged or re-used. Catalytic oxidation in supercritical water is one potential means of treating coal-conversion wastewaters, and this project examined the reactions of phenol over different heterogeneous oxidation catalysts in supercritical water. More specifically, the authors examined the oxidation of phenol over a commercial catalyst and over bulk MnO{sub 2}, bulk TiO{sub 2}, and CuO supported on Al{sub 2}O{sub 3}. They used phenol as the model pollutant because it is ubiquitous in coal-conversion wastewaters and there is a large database for non-catalytic supercritical water oxidation (SCWO) with which they can contrast results from catalytic SCWO. The overall objective of this research project is to obtain the reaction engineering information required to evaluate the utility of catalytic supercritical water oxidation for treating wastes arising from coal conversion processes. All four materials were active for catalytic supercritical water oxidation. Indeed, all four materials produced phenol conversions and CO{sub 2} yields in excess of those obtained from purely homogeneous, uncatalyzed oxidation reactions. The commercial catalyst was so active that the authors could not reliably measure reaction rates that were not limited by pore diffusion. Therefore, they performed experiments with bulk transition metal oxides. The bulk MnO{sub 2} and TiO{sub 2} catalysts enhance both the phenol disappearance and CO{sub 2} formation rates during SCWO. MnO{sub 2} does not affect the selectivity to CO{sub 2}, or to the phenol dimers at a given phenol conversion. However, the selectivities to CO{sub 2} are increased and the selectivities to phenol dimers are decreased in the presence of TiO{sub 2}, which are desirable trends for a catalytic SCWO process. The role of the catalyst appears to be accelerating the

  14. Oxidation of coal and coal pyrite mechanisms and influence on surface characteristics. Technical progress report, [March--May 1992

    SciTech Connect

    Doyle, F.M.

    1992-06-30

    during the seventh quarter, electrokinetic, humic acid extraction and film flotation tests were done on oxidized samples of Upper Freeport coal from the Troutville {number_sign} 2 Mine, Clearfield County, Pennsylvania. Scanning electron microscopy and energy dispersive X-ray analysis was done to characterize the morphology and composition of the surface of as-received coal, oxidized coal, oxidized coal after extraction of humic acids and humic acid extracted from oxidized coal. In addition, electrochemical studies were done on electrodes prepared from coal pyrite samples.

  15. Flotation and flocculation chemistry of coal and oxidized coals: Technical progress report, June 15, 1988--September 15, 1988

    SciTech Connect

    Somasundaran, P.

    1988-01-01

    This project is designed to develop an understanding of the fundamentals involved in flotation and flocculation chemistry of coal, and of coal in various states of oxidation. The main objective of this study is to elucidate mechanisms by which surface interactions between coal and various reagents enhance the benefication of coal. The effect of oxidation on the modification of surface characteristics of coal will also be studied. 1 ref., 7 figs.

  16. Oxidation of coal and coal pyrite mechanisms and influence on surface characteristics. Technical progress report, December 31, 1992

    SciTech Connect

    Doyle, F.M.

    1992-12-31

    During the ninth quarter, electrochemical experiments were done on electrodes prepared from Upper Freeport coal pyrite and Pittsburgh coal pyrite samples provided by the US Bureau of Mines, Pittsburgh Research Center, Pennsylvania. Scanning electron microscopy and energy dispersive X-ray analysis were done to characterize the morphology and composition of the surface of as-received coal, oxidized coal and coal pyrite. In addition, electrokinetic tests were done on Upper Freeport coal pyrite.

  17. Oxidation of coal and coal pyrite mechanisms and influence on surface characteristics

    SciTech Connect

    Doyle, F.M.

    1991-09-24

    The objective of this research is to develop a mechanistic understanding of the oxidation of coal and coal pyrite, and to correlate the intrinsic physical and chemical properties of these minerals, along with changes resulting from oxidation, with those surface properties that influence the behavior in physical coal cleaning processes. The results will provide fundamental insight into oxidation, in terms of the bulk and surface chemistry, the microstructure, and the semiconductor properties of the pyrite. During the fourth quarter, characterization and oxidation tests were done on Upper Freeport coal from the Troutville {number sign}2 Mine, Clearfield County, Pennsylvania. In addition, standard test methods for characterizing pyrite-bearing materials were studied. 3 figs., 2 tabs.

  18. Oxidative derivatization and solubilization of coal. Final report. Period: October 1, 1986 - April 30, 1988

    SciTech Connect

    Schulz, J.G.; Porowski, E.N.; Straub, A.M.

    1988-05-01

    We investigated the solubilization of coal by oxidative means to produce motor fuels. Nitric acid was used in the first of two approaches taken to cleave aliphatic linkages in coal and reduce the size of its macrostructure. Mild conditions, with temperatures up to a maximum of 75 C, and nitric acid concentrations below 20% by weight, characterize this process. The solid product, obtained in high yields, is soluble in polar organic solvents. Lower alcohols, methanol in particular, are of interest as carrier solvents in diesel fuel applications. Coals investigated were New York State peat, Wyodak subbituminous coal, North Dakota lignite, and Illinois No. 6 bituminous coal. The lower tank coals were easily converted and appear well suited to the process, while the bituminous Illinois No. 6 and Pitt Seam coals were unreactive. We concentrated our efforts on Wyodak coal and North Dakota lignite. Reaction conditions with regards to temperature, acid concentration, and time were optimized to obtain high product selectivity at maximum conversion. A continuous process scheme was developed for single pass coal conversions of about 50% to methanol-soluble product.

  19. 2000 resource assessment of selected coal beds and zones in the Northern and Central Appalachian Basin coal regions

    USGS Publications Warehouse

    Northern and Central Appalachian Basin Coal Regions Assessment Team

    2001-01-01

    This report includes results of a digital assessment of six coal beds or zones in the Northern and Central Appalachian Basin coal regions that produce over 15 percent of the Nation's coal. Other chapters include an executive summary, a report on geology and mining, a report summarizing other selected coal zones that were not assessed, and a report on USGS coal availability and recoverablity studies in the Northern and Central Appalachian Basin coal regions.

  20. Selective solvent absorption in coal conversion

    SciTech Connect

    Larsen, J.W.; Amui, J.

    1992-06-01

    The objectives of this research are: (1) to determine the importance of the presence of added hydrogen donor compounds within the coal in the first stage of direct liquefaction processes; and (2) to determine the composition of the solvent absorbed by and present within the coal in the first stages of direct coal liquefaction. Scope of work study the conversion of Argonne Premium coals in tetralin and 2-t-butyltetralin and compare the following: conversion to soluble products and product composition. Hydrogen donated by both solvents will be measured by gas chromatography and the same technique will be used to establish the amount of dealkylation of 2-t-butyltetralin. Reactions will be performed at several different temperatures for varying amounts of time.

  1. Shield support selection based on geometric characteristics of coal seam

    SciTech Connect

    K. Goshtasbi; K. Oraee; F. Khakpour-yeganeh

    2006-01-15

    The most initial investment in longwall face equipping is the cost of powered support. Selection of proper shields for powered supports is based on load, geometric characterization of coal seams and economical considerations.

  2. NITRIC OXIDE FORMATION DURING PULVERIZED COAL COMBUSTION

    EPA Science Inventory

    Data on the overall conversion of coal-nitrogen to NOx were obtained at 1250 K and 1750 K for a residence time of one second. The conversion of coal-nitrogen to NOx decreased monotonically with increasing fuel/oxygen equivalence ratio and decreased slightly with increasing temper...

  3. Innovative Clean Coal Technology (ICCT). Demonstration of Selective Catalytic Reduction (SCR) technology for the control of nitrogen oxide (NO{sub x}) emissions from high-sulfur coal-fired boilers: Volume 2, Appendices A--N. Final report

    SciTech Connect

    1996-10-01

    Volume 2 contains the following appendices: Appendix A, Example Material Safety Data Sheet; Appendix B, Initial Site Characterization Test Results; Appendix C, Testing Proposal, Southern Research Institute; Appendix D, Example Laboratory Catalyst Test Protocol; Appendix E, Detailed Coal Analysis Data; Appendix F, Standard Methods-QA/QC Document; Appendix G, Task No. 1 Commissioning Tests; Appendix H, Task No. 2 Commissioning Tests; Appendix I, First Parametric Sequence Spreadsheets; Appendix J, Second Parametric Sequence Spreadsheets; Appendix K, Third Parametric Sequence Spreadsheets; Appendix L, Fourth Parametric Sequence Spreadsheets; Appendix M, Fifth Parametric Sequence Spreadsheets; and Appendix N, First Series-Manual APH Tests.

  4. Oxidation of pyrite in coal to magnetite

    USGS Publications Warehouse

    Thorpe, A.N.; Senftle, F.E.; Alexander, C.C.; Dulong, F.T.

    1984-01-01

    When bituminous coal is heated in an inert atmosphere (He) containing small amounts of oxygen at 393-455 ??C, pyrite (FeS2) in coal is partially converted to magnetite (Fe304). The maximum amount of Fe304 formed during the time of heating corresponds to 5-20% of the total pyrite present, depending on the coal sample. The magnetite forms as an outer crust on the pyrite grains. The fact that the magnetic properties of the pyrite grains are substantially increased by the magnetite crust suggests that pyrite can be separated from coal by use of a low magnetic field. In a laboratory test, 75% removal is obtained by means of a 500 Oe magnet on three samples, and 60% on a fourth sample. ?? 1984.

  5. Desulphurization of coal via low temperature atmospheric alkaline oxidation.

    PubMed

    Liu, Kaicheng; Yang, Ji; Jia, Jinping; Wang, Yaling

    2008-03-01

    Different from other options which usually required strict conditions, a method combining atmospheric oxidization and chemical cleaning with alkali solutions was employed to desulphur coals at temperature around 90 degrees C. The data show that 66% organic sulphur, 44% sulphide sulphur, and 15% pyrite sulphur were lost when the coal was treated in 0.25M NaOH at 90 degrees C, while the solution being aerated at the flow rate of 0.136m3h(-1). The rate increased to 73% for organic sulphur, 83% for sulphide sulphur and 84% for pyrite sulphur when the previous coal was further treated in acidic solution containing HCl at pH 1 for another hour. The mechanism of desulphurization was explored using inductively coupled plasma mass spectrometry, X-ray photoelectron spectroscopy and infrared. It was found out that the bond of -CS was broken by atmospheric oxygen in basic environment, leading to the lost of organic sulphur in coal. Scanning electron microscope data show that the physical structure of the coal was not adversely affected by the treatment and thermogravimetric analysis results prove that the pyrolysis behavior remained unchanged, indicating that the burning process of the coal would not be adversely affected. Unlike other oxidizing methods, this technique does not lower the heating value of the coal which was manifested by relevant data.

  6. Molecular accessibility in oxidized and dried coals. Quarterly report, October--December 1993

    SciTech Connect

    Kispert, L.D.

    1993-12-01

    The objective of this research project is to determine the molecular and structural changes that occur in swelled coal as a result of oxidation and moisture loss both in the presence and absence of light using our newly developed EPR spin probe method. The proposed study will make it possible to deduce the molecular accessibility distribution in swelled, oxidized APCS coal for each rank as a function of (1) size (up to 6nm) and shape, (2) the relative acidic/basic reactive site distributions, (3) the role of hydrogen bonding and (4) the changes in the size and shape distribution of the accessible regions of the oxidized coal as a function of swelling solvents. The advantage of the EPR method is that it permits molecules of selected shape, size and chemical reactivity to be used as probes of molecularly accessible regions of swelled coal. From such data an optimum catalyst can be designed to convert oxidized coal into a more convenient form and methods can be devised to lessen the detrimental weathering processes.

  7. Desulfurization of coal: Enhanced selectivity using phase transfer catalysts. Final technical report, September 1, 1995--August 31, 1996

    SciTech Connect

    Palmer, S.R.; Hippo, E.J.

    1997-05-01

    Due to environmental problems related to the combustion of high sulfur Illinois coal, there continues to be interest in the development of viable pre-combustion desulfurization processes. Recent studies by the authors have obtained very good sulfur removals but the reagents that are used are too expensive. Use of cheaper reagents leads to a loss of desired coal properties. This study investigated the application of phase transfer catalysts to the selective oxidation of sulfur in coal using air and oxygen as oxidants. The phase transfer catalyst was expected to function as a selectivity moderator by permitting the use of milder reaction conditions than otherwise necessary. This would enhance the sulfur selectivity and help retain the heating value of the coal. The use of certain coal combustion wastes for desulfurization, and the application of cerium (IV) catalyzed air oxidations for selective sulfur oxidation were also studied. If successful this project would have lead to the rapid development of a commercially viable desulfurization process. This would have significantly improved the marketability of Illinois coal. However, the phase transfer catalysts, the cerium and the scrubber sledge did not catalize the sulfur removal significantly.

  8. Oxidation of coal and coal pyrite mechanisms and influence on surface characteristics. Technical progress report, [September--December 1991

    SciTech Connect

    Doyle, F.M.

    1992-01-28

    The objective of this research is to develop a mechanistic understanding of the oxidation of coal and coal pyrite, and to correlate the intrinsic physical and chemical properties of these minerals, along with changes resulting from oxidation, with those surface properties that influence the behavior in physical coal cleaning processes. The results will provide fundamental insight into oxidation, in terms of the bulk and surface chemistry, the microstructure, and the semiconductor properties of the pyrite. During the fifth quarter, wet chemical and dry oxidation tests were done on Upper Freeport coal from the Troutville {number_sign}2 Mine, Clearfield County, Pennsylvania.

  9. Colloidal stability of coal-simulated suspensions in selective agglomeration

    SciTech Connect

    Schurger, M.L.

    1989-01-01

    A coal suspension was simulated by using graphite to simulate the carbonaceous fraction and kaolinite clay to simulate the ash fraction. Separate studies on each material established their response to additions of oxidized pyrite (ferrous sulfate) and a humic acid simulate (salicylic acid) in terms of zeta potentials profiles with pH and Ionic strength. Concentrations of iron and salicylic acid evaluated were 4.5 {times} 10{sup {minus}3} M and 2.0 {times} 10{sup {minus}4} M, respectively. The zeta potentials profiles of graphite, clay and hexadecane were negative throughout the pH ranges studied. The addition of iron lowered the zeta potentials all of the suspensions under all pH and ionic strength conditions. Salicylic acid decreased the graphite and hexadecane zeta potentials but had no effect on the clay zeta potential profiles. Agglomeration of graphite with bridging liquid shows distinct time dependent rate mechanisms, a initial growth of graphite agglomerates followed by consolidation phase. Graphite agglomeration was rapid with the maximum amount of agglomerate volume growth occurring in under 2-4 minutes. Agglomeration in the first two minutes was characterized by a 1st order rate mechanism. The presence of either Iron and salicylic acid generally improved the first order rates. The addition of clay also improved the first order rates except in the presence of salicylic acid. Heteroagglomeration of graphite with clay was found by hydrodynamic arguments to be unfavored. A multicomponent population balance model which had been developed for evaluating collision efficiencies of coal, ash and pyrite selective agglomeration was evaluated to explain these results. The growth and consolidation characteristics of graphite agglomeration for the experimental conditions examined herein revealed the limitations of such as model for this application.

  10. Mechanisms for selective coalescence of coals: Fossil Energy quarterly report, 1 October 1987--31 December 1987

    SciTech Connect

    Wheelock, T.D.; Markuszewski, R.; Fan, C.W.; Venkatadri, R.; Labuschagne, B.C.J.; Hu, Y.C.; Tyson, D.

    1987-12-01

    The overall objective is to determine the basic mechanisms which underlie a number of selective coalescence or oil agglomeration processes that have been proposed for beneficiating fine-size coal. Recent work has shown that the oil agglomeration recovery of less hydrophobic Illinois No. 6 coal is reduced by an increase on ionic strength of the suspending medium. Also the oil agglomeration recovery of iron pyrite is reduced by an increase in ionic strength and the reduction is affected by the cations present. Thus, pyrite recovery is affected increasingly by Na/sup +/, Ca/sup + +/, and Mg/sup + +/ ions in that order. To study the effect of mild surface oxidation on the oil agglomeration of Pittsburgh seam coal, a freshly ground sample of the coal was exposed to air at room temperature for one week. When agglomerated with heptane, the recovery from neutral or acidic suspensions was similar to that of untreated coal, but the recovery from basic suspensions was lower than that of untreated coal. The total sulfur content of the agglomerated product was significantly lower for the treated coal. The use of magnesium salts as selective depressants for pyrite was investigated and found to be very effective in the separation of a synthetic mixture of hydrophobic Upper Freeport coal and pyrite by oil agglomeration. However, when a magnesium salt was applied to the separation of a synthetic mixture of the less hydrophobic Illinois No. 6 coal and pyrite, both coal and pyrite were depressed. 3 refs., 12 figs., 4 tabs.

  11. Nitrogen oxide emissions from coal fired MHD plants

    SciTech Connect

    Chapman, J.N.

    1996-03-01

    In this topical report, the nitrogen oxide emission issues from a coal fired MHD steam combined cycle power plant are summarized, both from an experimental and theoretical/calculational viewpoint. The concept of staging the coal combustion to minimize NO{sub x} is described. The impact of NO{sub x} control design choices on electrical conductivity and overall plant efficiency are described. The results of the NO{sub x} measurements in over 3,000 hours of coal fired testing are summarized. A chemical kinetics model that was used to model the nooks decomposition is described. Finally, optimum design choices for a low nooks plant are discussed and it is shown that the MHD Steam Coal Fired Combined Cycle Power Plant can be designed to operate with nooks emissions less than 0.05 lbm/MMBTU.

  12. Protocols for the selective cleavage of carbon-sulfur bonds in coal. Technical report, December 1, 1992--February 28, 1993

    SciTech Connect

    Bausch, M.; Ho, K.K.

    1993-05-01

    Chemical reactions that result in carbon-sulfur bond cleavage are an essential aspect of any protocol designed to remove organic sulfur from coal. Planned in the second year of our project Protocols for the Selective Cleavage of Carbon-Sulfur Bonds in Coal are investigations of reactions in which organic sulfur-containing coal model compounds are subjected to different conditions of temperature, solvent mixtures and radiation. Other investigations that will result in analyses of the likelihood of C-S bond cleavages resulting from various oxidative processes will also be undertaken. Summarized in this quarterly report are results of our investigations of the following topics: (a) desulfurization of coal model sulfones; (b) desulfurization of coal model sulfides; (c) photooxidation of organic sulfides; and (d) photolytic desulfurization of coal.

  13. Ultrasound assisted, thermally activated persulfate oxidation of coal tar DNAPLs.

    PubMed

    Peng, Libin; Wang, Li; Hu, Xingting; Wu, Peihui; Wang, Xueqing; Huang, Chumei; Wang, Xiangyang; Deng, Dayi

    2016-11-15

    The feasibility of ultrasound assisted, thermally activated persulfate for effective oxidation of twenty 2-6 ringed coal tar PAHs in a biphasic tar/water system and a triphasic tar/soil/water system were investigated and established. The results indicate that ultrasonic assistance, persulfate and elevated reaction temperature are all required to achieve effective oxidation of coal tar PAHs, while the heating needed can be provided by ultrasonic induced heating as well. Further kinetic analysis reveals that the oxidation of individual PAH in the biphasic tar/water system follows the first-order kinetics, and individual PAH oxidation rate is primary determined by the mass transfer coefficients, tar/water interfacial areas, the aqueous solubility of individual PAH and its concentration in coal tar. Based on the kinetic analysis and experimental results, the contributions of ultrasound, persulfate and elevated reaction temperature to PAHs oxidation were characterized, and the effects of ultrasonic intensity and oxidant dosage on PAHs oxidation efficiency were investigated. In addition, the results indicate that individual PAH degradability is closely related to its reactivity as well, and the high reactivity of 4-6 ringed PAHs substantially improves their degradability. PMID:27450342

  14. Ultrasound assisted, thermally activated persulfate oxidation of coal tar DNAPLs.

    PubMed

    Peng, Libin; Wang, Li; Hu, Xingting; Wu, Peihui; Wang, Xueqing; Huang, Chumei; Wang, Xiangyang; Deng, Dayi

    2016-11-15

    The feasibility of ultrasound assisted, thermally activated persulfate for effective oxidation of twenty 2-6 ringed coal tar PAHs in a biphasic tar/water system and a triphasic tar/soil/water system were investigated and established. The results indicate that ultrasonic assistance, persulfate and elevated reaction temperature are all required to achieve effective oxidation of coal tar PAHs, while the heating needed can be provided by ultrasonic induced heating as well. Further kinetic analysis reveals that the oxidation of individual PAH in the biphasic tar/water system follows the first-order kinetics, and individual PAH oxidation rate is primary determined by the mass transfer coefficients, tar/water interfacial areas, the aqueous solubility of individual PAH and its concentration in coal tar. Based on the kinetic analysis and experimental results, the contributions of ultrasound, persulfate and elevated reaction temperature to PAHs oxidation were characterized, and the effects of ultrasonic intensity and oxidant dosage on PAHs oxidation efficiency were investigated. In addition, the results indicate that individual PAH degradability is closely related to its reactivity as well, and the high reactivity of 4-6 ringed PAHs substantially improves their degradability.

  15. The oxidizing power of illinois coal. I. The reaction with titanous chloride

    USGS Publications Warehouse

    Yoke, G.R.; Harman, C. Alex

    1941-01-01

    Illinois coals which have been exposed to air or oxygen show a small but definite ability to oxidize titanous chloride. This oxidizing power is gained very rapidly when freshly ground coal is exposed to air. Neither the magnitude nor the rapid increase of this oxidizing power can be accounted for entirely by the presence or the formation of soluble ferric compounds in the coal.

  16. Integrating catalytic coal gasifiers with solid oxide fuel cells

    SciTech Connect

    Siefert, N.; Shamsi, A.; Shekhawat, D.; Berry, D.

    2010-01-01

    A review was conducted for coal gasification technologies that integrate with solid oxide fuel cells (SOFC) to achieve system efficiencies near 60% while capturing and sequestering >90% of the carbon dioxide [1-2]. The overall system efficiency can reach 60% when a) the coal gasifier produces a syngas with a methane composition of roughly 25% on a dry volume basis, b) the carbon dioxide is separated from the methane-rich synthesis gas, c) the methane-rich syngas is sent to a SOFC, and d) the off-gases from the SOFC are recycled back to coal gasifier. The thermodynamics of this process will be reviewed and compared to conventional processes in order to highlight where available work (i.e. exergy) is lost in entrained-flow, high-temperature gasification, and where exergy is lost in hydrogen oxidation within the SOFC. The main advantage of steam gasification of coal to methane and carbon dioxide is that the amount of exergy consumed in the gasifier is small compared to conventional, high temperature, oxygen-blown gasifiers. However, the goal of limiting the amount of exergy destruction in the gasifier has the effect of limiting the rates of chemical reactions. Thus, one of the main advantages of steam gasification leads to one of its main problems: slow reaction kinetics. While conventional entrained-flow, high-temperature gasifiers consume a sizable portion of the available work in the coal oxidation, the consumed exergy speeds up the rates of reactions. And while the rates of steam gasification reactions can be increased through the use of catalysts, only a few catalysts can meet cost requirements because there is often significant deactivation due to chemical reactions between the inorganic species in the coal and the catalyst. Previous research into increasing the kinetics of steam gasification will be reviewed. The goal of this paper is to highlight both the challenges and advantages of integrating catalytic coal gasifiers with SOFCs.

  17. KINETICS OF DIRECT OXIDATION OF H2S IN COAL GAS TO ELEMENTAL SULFUR

    SciTech Connect

    K.C. Kwon

    2002-02-01

    Removal of hydrogen sulfide (H{sub 2}S) from coal gasifier gas and sulfur recovery are key steps in the development of Department of Energy's (DOE's) advanced Vision 21 plants that employ coal and natural gas and produce electric power and clean transportation fuels. These Vision 21 plants will require highly clean coal gas with H{sub 2}S below 1 ppm and negligible amounts of trace contaminants such as hydrogen chloride, ammonia, alkali, heavy metals, and particulate. The conventional method of sulfur removal and recovery employing amine, Claus, and tail-gas treatment is very expensive. A second generation approach developed under DOE's sponsorship employs hot-gas desulfurization (HGD) using regenerable metal oxide sorbents followed by Direct Sulfur Recovery Process (DSRP). However, this process sequence does not remove trace contaminants and is targeted primarily towards the development of advanced integrated gasification combined cycle (IGCC) plants that produce electricity (not both electricity and transportation fuels). There is an immediate as well as long-term need for the development of cleanup processes that produce highly clean coal gas for next generation Vision 21 plants. To this end, a novel process is now under development at Research Triangle Institute (RTI) in which the H{sub 2}S in coal gas is directly oxidized to elemental sulfur over a selective catalyst. Such a process is ideally suited for coal gas from commercial gasifiers with a quench system to remove essentially all the trace contaminants except H{sub 2}S. This direct oxidation process has the potential to produce a super clean coal gas more economically than both conventional amine-based processes and HGD/DSRP. The objective of this research is to support the near- and long-term DOE efforts to commercialize this direct oxidation technology. Specifically, we aim to: Measure the kinetics of direct oxidation of H{sub 2}S to elemental sulfur over selective catalysts in the presence of major

  18. OXIDATION AND DEVOLATILIZATION OF NITROGEN IN COAL CHAR

    EPA Science Inventory

    The reactions of organically-bound nitrogen in coal char during combustion have been studied in a laboratory furnace using size-graded char particles prepared by the pyrolysis of a Montana lignite. The time-resolved variations of nitrogen-to-carbon ratio during char oxidation hav...

  19. The effect of coal bed dewatering and partial oxidation on biogenic methane potential

    USGS Publications Warehouse

    Jones, Elizabeth J.P.; Harris, Steve H.; Barnhart, Elliott P.; Orem, William H.; Clark, Arthur C.; Corum, Margo D.; Kirshtein, Julie D.; Varonka, Matthew S.; Voytek, Mary A.

    2013-01-01

    Coal formation dewatering at a site in the Powder River Basin was associated with enhanced potential for secondary biogenic methane determined by using a bioassay. We hypothesized that dewatering can stimulate microbial activity and increase the bioavailability of coal. We analyzed one dewatered and two water-saturated coals to examine possible ways in which dewatering influences coal bed natural gas biogenesis by looking at differences with respect to the native coal microbial community, coal-methane organic intermediates, and residual coal oxidation potential. Microbial biomass did not increase in response to dewatering. Small Subunit rRNA sequences retrieved from all coals sampled represented members from genera known to be aerobic, anaerobic and facultatively anaerobic. A Bray Curtis similarity analysis indicated that the microbial communities in water-saturated coals were more similar to each other than to the dewatered coal, suggesting an effect of dewatering. There was a higher incidence of long chain and volatile fatty acid intermediates in incubations of the dewatered coal compared to the water-saturated coals, and this could either be due to differences in microbial enzymatic activities or to chemical oxidation of the coal associated with O2 exposure. Dilute H2O2 treatment of two fractions of structural coal (kerogen and bitumen + kerogen) was used as a proxy for chemical oxidation by O2. The dewatered coal had a low residual oxidation potential compared to the water-saturated coals. Oxidation with 5% H2O2 did increase the bioavailability of structural coal, and the increase in residual oxidation potential in the water saturated coals was approximately equivalent to the higher methanogenic potential measured in the dewatered coal. Evidence from this study supports the idea that coal bed dewatering could stimulate biogenic methanogenesis through partial oxidation of the structural organics in coal once anaerobic conditions are restored.

  20. A new approach in ultrapurification of coal by selective flocculation

    SciTech Connect

    Moudgil, B.M.

    1989-12-01

    The mathematical and computational model of the selective flocculation process for separating coal pyrite from coal has been further developed. Computational simulation in Fortran (as opposed to Turbo Pascal) has enabled consideration of 10{sup 6} particles which is of the order of number of particles encountered in experimental systems. Relative importance of {Phi} (active sites ratio) over {Theta} (fractional surface coverage) indicated that the desired separation may not be possible by controlling the polymer dosage, and that it is more important to select a polymer which has no affinity for the inert component(s). Also, feed composition, according to the simulations, should not have any significant influence over the selectivity. Selective flocculation tests with two previously selected polymers indicated that separation of coal pyrite from coal is possible. Effect of feed composition, however, was found to be different than predicted by the computational model. This has been attributed to the experimental parameters which are not optimized at the present time. 3 refs., 3 figs., 5 tabs.

  1. Oxidation of coal and coal pyrite mechanisms and influence on surface characteristics. Technical progress report, June 1995--August 1995

    SciTech Connect

    Doyle, F.M.

    1996-03-01

    The objective of this research is to develop a mechanistic understanding of the oxidation of coal and coal pyrite, and to correlate the intrinsic physical and chemical properties of these minerals, along with changes resulting from oxidation, with those surface properties that influence the behavior in physical cleaning processes. The action of coal and pyrite as reducing agents and as waste processing sorptive material for wastes outside the industry are also discussed.

  2. Surface Properties of Photo-Oxidized Bituminous Coals: Final report

    SciTech Connect

    1998-09-01

    Natural weathering has a detrimental effect on the hydrophobic nature of coal, which in turn can influence clean-coal recovery during flotation. Few techniques are available that can establish the quality of coal surfaces and that have a short analysis time to provide input for process control. Luminescence emissions which can be quantified with an optical microscope and photometer system, are measurably influenced by degree of weathering as well as by mild storage deterioration. In addition, it has been shown that when vitrinite is irradiated with a relatively high intensity flux of violet- or ultraviolet- light in the presence of air, photo-oxidation of the surface occurs. The combination of measuring the change in luminescence emission intensity with degree of surface oxidation provided the impetus for the current investigation. The principal aim of this research was to determine whether clear correlations could be established among surface oxygen functionality, hydrophobicity induced by photo-oxidation, and measurements of luminescence intensity and alteration. If successful, the project would result in quantitative luminescence techniques based on optical microscopy that would provide a measure of the changes in surface properties as a function of oxidation and relate them to coal cleanability. Two analytical techniques were designed to achieve these goals. Polished surfaces of vitrain bands or a narrow size fraction of powdered vitrain concentrates were photo-oxidized using violet or ultraviolet light fluxes and then changes in surface properties and chemistry were measured using a variety of near-surface analytical techniques. Results from this investigation demonstrate that quantitative luminescence intensity measurements can be performed on fracture surfaces of bituminous rank coals (vitrains) and that the data obtained do reveal significant variations depending upon the level of surface oxidation. Photo-oxidation induced by violet or ultraviolet light

  3. Selectivity improvement in the solvent refined coal process. I - Detailed first-stage reaction studies - Coal mineral catalysis. II - Detailed second-stage reaction studies - Hydrotreating of coal liquids

    NASA Astrophysics Data System (ADS)

    Garg, D.; Tarrer, A. R.; Guin, J. A.; Curtis, C. W.; Clinton, J. H.

    1980-08-01

    A two stage process is investigated for the production of a low-sulfur solid SRC-I (solvent refined coal) type boiler fuel with a minimum consumption of hydrogen. The first stage involves the scavenging action of coal minerals. Mineral additives (e.g., iron oxide and iron) increase selectivity for hydrodesulfurization over hydrogenation in coal liquefaction reactions. Mineral residues from SRC processes show insignificant desulfurization activity, but through oxidation, their sulfurization activity increases to significant levels without an increase in hydrogenation activity. The sulfur removal activity of an additive depends on its surface area. The second stage involves hydrotreating the dissolver effluent for maximum sulfur removal, with a minimum consumption of hydrogen. The effect of a wide range of variables on hydrotreating of a coal liquid in the presence of a commercial Co-Mo-Al catalyst is evaluated. The variables include catalyst loading, hydrogen partial pressure, reaction temperature and time.

  4. [Comprehensive fuzzy evaluation of nitrogen oxide control technologies for coal-fired power plants].

    PubMed

    Yu, Chao; Wang, Shu-xiao; Hao, Ji-ming

    2010-07-01

    A multi-level assessment index system was established to quantitatively and comprehensively evaluate the performance of typical nitrogen oxide control technologies for coal-fired power plants. Comprehensive fuzzy evaluation was conducted to assess six NO, control technologies, including low NO, burner (LNB), over the fire (OFA), flue gas reburning (Reburning), selective catalyst reduction (SCR), selective non-catalyst reduction (SNCR) and hybrid SCR/SNCR. Case studies indicated that combination of SCR and LNB are the optimal choice for wall-fired boilers combusting anthracite coal which requires NO, removal efficiency to be over 70%, however, for W-flame or tangential boilers combusting bituminous and sub-bituminous coal which requires 30% NO, removal, LNB and reburning are better choices. Therefore, we recommend that in the developed and ecological frangible regions, large units burning anthracite or meager coal should install LNB and SCR and other units should install LNB and SNCR. In the regions with environmental capacity, units burning anthracite or meager coal shall install LNB and SNCR, and other units shall apply LNB to reduce NO, emissions.

  5. Oxidation of coal and coal pyrite mechanisms and influence on surface characteristics. Technical progress report, September 30, 1992

    SciTech Connect

    Doyle, F.M.

    1992-12-31

    The objective of this research is to develop a mechanistic understanding of the oxidation of coal and coal pyrite, and to correlate the intrinsic physical and chemical properties of these minerals, along with changes resulting from oxidation, with those surface properties that influence the behavior in physical cleaning processes. The results will provide fundamental insight into oxidation, in terms of the bulk and surface chemistry, the microstructure, and the semiconductor properties of the pyrite. During the eighth quarter, wet chemical and dry oxidation tests were done on Upper Freeport coal from the Troutville {number_sign}2 Mine, Clearfield County, Pennsylvania. In addition electrochemical experiments were done on electrodes prepared from Upper Freeport coal pyrite and Pittsburgh coal pyrite samples provided by the US Bureau of Mines, Pittsburgh Research Center, Pennsylvania.

  6. Enhanced coal hydrogasification via oxidative pretreatment. Final technical report

    SciTech Connect

    Miller, D.J.

    1992-04-16

    The gasification of coal char by hydrogen is much slower than in steam or carbon dioxide; moreover, hydrogasification rate in pure hydrogen decreases sharply with conversion for most carbons. To overcome this kinetic behavior, the oxidation of the char prior to and during hydrogasification has been investigated as a means of enhancing hydro gasification rate. Kinetic rate studies under well-characterized conditions have been complemented by careful surface analyses to characterize oxygen on the char surface prior to and during hydrogasification.

  7. Selective Oxidizer For Removal Of Carbon Monoxide

    NASA Technical Reports Server (NTRS)

    Trocciola, John C.; Schroll, Craig R.; Lesieur, Roger R.

    1996-01-01

    Catalytic apparatus selectively oxidizes most of carbon monoxide (without oxidizing hydrogen) in stream of reformed fuel gas fed to low-temperature fuel cell. Multiple catalytic stages at progressively lower temperatures operate without becoming poisoned. Catalysts used to oxidize CO selectively include platinum on alumina and commercial catalyst known as "Selectoxo."

  8. Recovery of iron oxide from coal fly ash

    DOEpatents

    Dobbins, Michael S.; Murtha, Marlyn J.

    1983-05-31

    A high quality iron oxide concentrate, suitable as a feed for blast and electric reduction furnaces is recovered from pulverized coal fly ash. The magnetic portion of the fly ash is separated and treated with a hot strong alkali solution which dissolves most of the silica and alumina in the fly ash, leaving a solid residue and forming a precipitate which is an acid soluble salt of aluminosilicate hydrate. The residue and precipitate are then treated with a strong mineral acid to dissolve the precipitate leaving a solid residue containing at least 90 weight percent iron oxide.

  9. STUDY OF THE EFFECT OF CHLORINE ADDITION ON MERCURY OXIDATION BY SCR CATALYST UNDER SIMULATED SUBBITUMINOUS COAL FLUE GAS

    EPA Science Inventory

    An entrained flow reactor is used to study the effect of addition of chlorine-containing species on the oxidation of elemental mercury (Hgo)by a selective catalytic reduction (SCR) catalyst in simulated subbituminous coal combustion flue gas. The combustion flue gas was doped wit...

  10. Selective Adsorption and Selective Transport Diffusion of CO2-CH4 Binary Mixture in Coal Ultramicropores.

    PubMed

    Zhao, Yongliang; Feng, Yanhui; Zhang, Xinxin

    2016-09-01

    The adsorption and diffusion of the CO2-CH4 mixture in coal and the underlying mechanisms significantly affect the design and operation of any CO2-enhanced coal-bed methane recovery (CO2-ECBM) project. In this study, bituminous coal was fabricated based on the Wiser molecular model and its ultramicroporous parameters were evaluated; molecular simulations were established through Grand Canonical Monte Carlo (GCMC) and Molecular Dynamic (MD) methods to study the effects of temperature, pressure, and species bulk mole fraction on the adsorption isotherms, adsorption selectivity, three distinct diffusion coefficients, and diffusivity selectivity of the binary mixture in the coal ultramicropores. It turns out that the absolute adsorption amount of each species in the mixture decreases as temperature increases, but increases as its own bulk mole fraction increases. The self-, corrected, and transport diffusion coefficients of pure CO2 and pure CH4 all increase as temperature or/and their own bulk mole fractions increase. Compared to CH4, the adsorption and diffusion of CO2 are preferential in the coal ultramicropores. Adsorption selectivity and diffusivity selectivity were simultaneously employed to reveal that the optimal injection depth for CO2-ECBM is 800-1000 m at 308-323 K temperature and 8.0-10.0 MPa. PMID:27518119

  11. Nitrogen oxides emission control options for coal-fired electric utility boilers

    SciTech Connect

    Ravi K. Srivastava; Robert E. Hall; Sikander Khan; Kevin Culligan; Bruce W. Lani

    2005-09-01

    Recent regulations have required reductions in emissions of nitrogen oxides (NOx) from electric utility boilers. To comply with these regulatory requirements, it is increasingly important to implement state-of-the-art NOx control technologies on coal-fired utility boilers. This paper reviews NOx control options for these boilers. It discusses the established commercial primary and secondary control technologies and examines what is being done to use them more effectively. Furthermore, the paper discusses recent developments in NOx controls. The popular primary control technologies in use in the United States are low-NOx burners and overfire air. Data reflect that average NOx reductions for specific primary controls have ranged from 35% to 63% from 1995 emissions levels. The secondary NOx control technologies applied on U.S. coal-fired utility boilers include reburning, selective noncatalytic reduction (SNCR), and selective catalytic reduction (SCR). Thirty-six U.S. coal-fired utility boilers have installed SNCR, and reported NOx reductions achieved at these applications ranged from 15% to 66%. Recently, SCR has been installed at 150 U.S. coal-fired utility boilers. Data on the performance of 20 SCR systems operating in the United States with low-NOx emissions reflect that in 2003, these units achieved NOx emission rates between 0.04 and 0.07 lb/106 Btu. 106 refs., 6 figs., 6 tabs.

  12. Nitrogen oxides emission control options for coal-fired electric utility boilers.

    PubMed

    Srivastava, Ravi K; Hall, Robert E; Khan, Sikander; Culligan, Kevin; Lani, Bruce W

    2005-09-01

    Recent regulations have required reductions in emissions of nitrogen oxides (NOx) from electric utility boilers. To comply with these regulatory requirements, it is increasingly important to implement state-of-the-art NOx control technologies on coal-fired utility boilers. This paper reviews NOx control options for these boilers. It discusses the established commercial primary and secondary control technologies and examines what is being done to use them more effectively. Furthermore, the paper discusses recent developments in NOx controls. The popular primary control technologies in use in the United States are low-NOx burners and overfire air. Data reflect that average NOx reductions for specific primary controls have ranged from 35% to 63% from 1995 emissions levels. The secondary NOx control technologies applied on U.S. coal-fired utility boilers include reburning, selective noncatalytic reduction (SNCR), and selective catalytic reduction (SCR). Thirty-six U.S. coal-fired utility boilers have installed SNCR, and reported NOx reductions achieved at these applications ranged from 15% to 66%. Recently, SCR has been installed at >150 U.S. coal-fired utility boilers. Data on the performance of 20 SCR systems operating in the United States with low-NOx emissions reflect that in 2003, these units achieved NOx emission rates between 0.04 and 0.07 lb/10(6) Btu.

  13. Selective flotation of fossil resin from western coal

    SciTech Connect

    Jensen, G.F.; Miller, J.D.

    1992-03-20

    The test program has demonstrated that: (1) technically, the new flotation technologies discovered at the University of Utah and then improved upon by Advanced Processing Technologies, Inc. provide a highly efficient means to selectively recover fossil resin from coal. The proof-of-concept continuous flotation circuit resulted in fossil resin recovery with the same separation efficiency as was obtained from laboratory bench-scale testing (more than 80% recovery at about 80% concentrate grade); and (2) economically, the selective flotation process has been shown to be sufficiently profitable to justify the development of a fossil resin industry based on this new flotation process. The proof-of-concept testing has resulted in significant interest from several coal mining companies and has sparked the desire of local and state government to establish a fossil resin industry in the Wasatch Plateau coal field. In this view, the results from the current proof-of-concept testing program have been successful. This special report provides theoretical and analytical data on some surface chemistry work pertinent to fossil resin characterization, and other efforts carried out during the past months.

  14. Interactions of selected bacterial isolates with DBT and solubilized coal

    SciTech Connect

    Key, D.H.; Fox, R.V.; Kase, R.S.; Willey, M.S.; Stoner, D.L.; Ward, T.E.

    1990-01-01

    We are studying the interactions of isolated bacteria with dibenzothiophene (DBT), a sulfur-containing model compound, and with a solubilized coal product derived from a high-organic-sulfur lignite. The sensitivity of the tetrazolium assay used to identify and study these strains was improved by substituting tetrazolium violet for triphenyltetrazolium. DBT metabolism by thirteen strains was investigated using qualitative and quantitative GC and GC-MS analyses. Growth medium and incubation time affect the extent of DBT degradation and the production of DBT metabolites. Under specific conditions, seven of the strains produce metabolites which elute close to the position of one or another of the biphenyl standards. However, when these samples are spiked with the standard compounds, the bacterial metabolites do not co-elute with the standards. The modification of solubilized high-organic-sulfur coal by six of these strains was also studied. No selective removal of sulfur relative to carbon was observed. 13 refs., 1 fig., 2 tabs.

  15. Pilot-scale study of the effect of selective catalytic reduction catalyst on mercury speciation in Illinois and Powder River Basin coal combustion flue gases.

    PubMed

    Lee, Chun W; Srivastava, Ravi K; Ghorishi, S Behrooz; Karwowski, Jarek; Hastings, Thomas W; Hirschi, Joseph C

    2006-05-01

    A study was conducted to investigate the effect of selective catalytic reduction (SCR) catalyst on mercury (Hg) speciation in bituminous and subbituminous coal combustion flue gases. Three different Illinois Basin bituminous coals (from high to low sulfur [S] and chlorine [Cl]) and one Powder River Basin (PRB) subbituminous coal with very low S and very low Cl were tested in a pilot-scale combustor equipped with an SCR reactor for controlling nitrogen oxides (NOx) emissions. The SCR catalyst induced high oxidation of elemental Hg (Hg0), decreasing the percentage of Hg0 at the outlet of the SCR to values <12% for the three Illinois coal tests. The PRB coal test indicated a low oxidation of Hg0 by the SCR catalyst, with the percentage of Hg0 decreasing from approximately 96% at the inlet of the reactor to approximately 80% at the outlet. The low Cl content of the PRB coal and corresponding low level of available flue gas Cl species were believed to be responsible for low SCR Hg oxidation for this coal type. The test results indicated a strong effect of coal type on the extent of Hg oxidation.

  16. Oxidation of coal-water slurry feed to hydrogasifier

    DOEpatents

    Lee, Bernard S.

    1976-01-01

    An aqueous coal slurry is preheated, subjected to partial oxidation and vaporization by injection of high pressure oxygen and is introduced into a top section of a hydrogasifier in direct contact with hot methane-containing effluent gases where vaporization of the slurry is completed. The resulting solids are reacted in the hydrogasifier and the combined gases and vapors are withdrawn and subjected to purification and methanation to provide pipeline gas. The amount of oxygen injected into the slurry is controlled to provide the proper thermal balance whereby all of the water in the slurry can be evaporated in contact with the hot effluent gases from the hydrogasifier.

  17. Demonstration of selective catalytic reduction (SCR) technology for the control of nitrogen oxide (NO{sub x}) emissions from high-sulfur coal-fired boilers. Draft final report

    SciTech Connect

    1996-06-14

    The primary goal of this project was to demonstrate the use of Selective Catalytic Reduction (SCR) to reduce NO{sub x} emissions from pulverized-coal utility boilers using medium- to high-sulfur US coal. The prototype SCR facility, built in and around the ductwork of Plant Crist Unit 5, consisted of three large SCR reactor units (Reactors A, B, and C), each with a design capacity of 5,000 standard cubic feet per minute (scfm) of flue gas, and six smaller reactors (Reactors D through J), each with a design capacity of 400 scfm of flue gas. The three large reactors contained commercially available SCR catalysts as offered by SCR catalyst suppliers. These reactors were coupled with small-scale air preheaters to evaluate (1) the long-term effects of SCR reaction chemistry on air preheater deposit formation and (2) the impact of these deposits on the performance of air preheaters. The small reactors were used to test additional varieties of commercially available catalysts. The demonstration project was organized into three phases: (1) Permitting, Environmental Monitoring Plan (EMP) Preparation, and Preliminary Engineering; (2) Detail Design Engineering and Construction; and (3) Operation, Testing, Disposition, and Final Report Preparation. Section 2 discusses the planned and actual EMP monitoring for gaseous, aqueous, and solid streams over the course of the SCR demonstration project; Section 3 summarizes sampling and analytical methods and discusses exceptions from the methods specified in the EMP; Section 4 presents and discusses the gas stream monitoring results; Section 5 presents and discusses the aqueous stream monitoring results; Section 6 presents and discusses the solid stream monitoring results; Section 7 discusses EMP-related quality assurance/quality control activities performed during the demonstration project; Section 8 summarizes compliance monitoring reporting activities; and Section 9 presents conclusions based on the EMP monitoring results.

  18. Kinetics of Direct Oxidation of H2S in Coal Gas to Elemental Sulfur

    SciTech Connect

    K.C. Kwon

    2005-11-01

    Removal of hydrogen sulfide (H{sub 2}S) from coal gasifier gas and sulfur recovery are key steps in the development of Department of Energy's (DOE's) advanced Vision 21 plants that produce electric power and clean transportation fuels with coal and natural gas. These Vision 21 plants will require highly clean coal gas with H{sub 2}S below 1 ppm and negligible amounts of trace contaminants such as hydrogen chloride, ammonia, alkali, heavy metals, and particulate. The conventional method of sulfur removal and recovery employing amine, Claus, and tail-gas treatment is very expensive. A second generation approach developed under DOE's sponsorship employs hot-gas desulfurization (HGD) using regenerable metal oxide sorbents followed by Direct Sulfur Recovery Process (DSRP). However, this process sequence does not remove trace contaminants and is targeted primarily towards the development of advanced integrated gasification combined cycle (IGCC) plants that produce electricity (not both electricity and transportation fuels). There is an immediate as well as long-term need for the development of cleanup processes that produce highly clean coal gas for next generation Vision 21 plants. To this end, a novel process is now under development at several research organizations in which the H{sub 2}S in coal gas is directly oxidized to elemental sulfur over a selective catalyst. Such a process is ideally suited for coal gas from commercial gasifiers with a quench system to remove essentially all the trace contaminants except H{sub 2}S. The direct oxidation of H{sub 2}S to elemental sulfur in the presence of SO{sub 2} is ideally suited for coal gas from commercial gasifiers with a quench system to remove essentially all the trace contaminants except H{sub 2}S. This direct oxidation process has the potential to produce a super clean coal gas more economically than both conventional amine-based processes and HGD/DSRP. The objectives of this research are to measure kinetics of direct

  19. Decaking of coal or oil shale during pyrolysis in the presence of iron oxides

    DOEpatents

    Rashid Khan, M.

    1988-05-05

    A method for producing a fuel from the pyrolysis of coal or oil shale in the presence of iron oxide in an inert gas atmosphere is described. The method includes the steps of pulverizing feed coal or oil shale, pulverizing iron oxide, mixing the pulverized feed and iron oxide, and heating the mixture in a gas atmosphere which is substantially inert to the mixture so as to form a product fuel, which may be gaseous, liquid and/or solid. The method of the invention reduces the swelling of coals, such as bituminous coal and the like, which are otherwise known to swell during pyrolysis. 4 figs., 8 tabs.

  20. Decaking of coal or oil shale during pyrolysis in the presence of iron oxides

    DOEpatents

    Khan, M. Rashid

    1989-01-01

    A method for producing a fuel from the pyrolysis of coal or oil shale in the presence of iron oxide in an inert gas atmosphere. The method includes the steps of pulverizing feed coal or oil shale, pulverizing iron oxide, mixing the pulverized feed and iron oxide, and heating the mixture in a gas atmosphere which is substantially inert to the mixture so as to form a product fuel, which may be gaseous, liquid and/or solid. The method of the invention reduces the swelling of coals, such as bituminous coal and the like, which are otherwise known to swell during pyrolysis.

  1. Studies on the Low-Temp Oxidation of Coal Containing Organic Sulfur and the Corresponding Model Compounds.

    PubMed

    Zhang, Lanjun; Li, Zenghua; Li, Jinhu; Zhou, Yinbo; Yang, Yongliang; Tang, Yibo

    2015-12-11

    This paper selects two typical compounds containing organic sulfur as model compounds. Then, by analyzing the chromatograms of gaseous low-temp oxidation products and GC/MS of the extractable matter of the oxidation residue, we summarizing the mechanism of low-temp sulfur model compound oxidation. The results show that between 30°C to 80°C, the interaction between diphenyl sulfide and oxygen is mainly one of physical adsorption. After 80°C, chemical adsorption and chemical reactions begin. The main reaction mechanism in the low-temp oxidation of the model compound diphenyl sulfide is diphenyl sulfide generates diphenyl sulfoxide, and then this sulfoxide is further oxidized to diphenyl sulphone. A small amount of free radicals is generated in the process. The model compound cysteine behaves differently from diphenyl sulfide. The main reaction low-temp oxidation mechanism involves the thiol being oxidized into a disulphide and finally evolving to sulfonic acid, along with SO₂ being released at 130°C and also a small amount of free radicals. We also conducted an experiment on coal from Xingcheng using X-ray photoelectron spectroscopy (XPS). The results show that the major forms of organic sulfur in the original coal sample are thiophene and sulfone. Therefore, it can be inferred that there is none or little mercaptan and thiophenol in the original coal. After low-temp oxidation, the form of organic sulfur changes. The sulfide sulfur is oxidized to the sulfoxide, and then the sulfoxide is further oxidized to a sulfone, and these steps can be easily carried out under experimental conditions. What's more, the results illustrate that oxidation promotes sulfur element enrichment on the surface of coal.

  2. Studies on the Low-Temp Oxidation of Coal Containing Organic Sulfur and the Corresponding Model Compounds.

    PubMed

    Zhang, Lanjun; Li, Zenghua; Li, Jinhu; Zhou, Yinbo; Yang, Yongliang; Tang, Yibo

    2015-01-01

    This paper selects two typical compounds containing organic sulfur as model compounds. Then, by analyzing the chromatograms of gaseous low-temp oxidation products and GC/MS of the extractable matter of the oxidation residue, we summarizing the mechanism of low-temp sulfur model compound oxidation. The results show that between 30°C to 80°C, the interaction between diphenyl sulfide and oxygen is mainly one of physical adsorption. After 80°C, chemical adsorption and chemical reactions begin. The main reaction mechanism in the low-temp oxidation of the model compound diphenyl sulfide is diphenyl sulfide generates diphenyl sulfoxide, and then this sulfoxide is further oxidized to diphenyl sulphone. A small amount of free radicals is generated in the process. The model compound cysteine behaves differently from diphenyl sulfide. The main reaction low-temp oxidation mechanism involves the thiol being oxidized into a disulphide and finally evolving to sulfonic acid, along with SO₂ being released at 130°C and also a small amount of free radicals. We also conducted an experiment on coal from Xingcheng using X-ray photoelectron spectroscopy (XPS). The results show that the major forms of organic sulfur in the original coal sample are thiophene and sulfone. Therefore, it can be inferred that there is none or little mercaptan and thiophenol in the original coal. After low-temp oxidation, the form of organic sulfur changes. The sulfide sulfur is oxidized to the sulfoxide, and then the sulfoxide is further oxidized to a sulfone, and these steps can be easily carried out under experimental conditions. What's more, the results illustrate that oxidation promotes sulfur element enrichment on the surface of coal. PMID:26690405

  3. Novel two stage bio-oxidation and chlorination process for high strength hazardous coal carbonization effluent.

    PubMed

    Manekar, Pravin; Biswas, Rima; Karthik, Manikavasagam; Nandy, Tapas

    2011-05-15

    Effluent generated from coal carbonization to coke was characterized with high organic content, phenols, ammonium nitrogen, and cyanides. A full scale effluent treatment plant (ETP) working on the principle of single stage carbon-nitrogen bio-oxidation process (SSCNBP) revealed competition between heterotrophic and autotrophic bacteria in the bio-degradation and nitrification process. The effluent was pretreated in a stripper and further combined with other streams to treat in the SSCNBP. Laboratory studies were carried on process and stripped effluents in a bench scale model of ammonia stripper and a two stage bio-oxidation process. The free ammonia removal efficiency of stripper was in the range 70-89%. Bench scale studies of the two stage bio-oxidation process achieved a carbon-nitrogen reduction at 6 days hydraulic retention time (HRT) operating in an extended aeration mode. This paper addresses the studies on selection of a treatment process for removal of organic matter, phenols, cyanide and ammonia nitrogen. The treatment scheme comprising ammonia stripping (pretreatment) followed by the two stage bio-oxidation and chlorination process met the Indian Standards for discharge into Inland Surface Waters. This treatment process package offers a techno-economically viable treatment scheme to neuter hazardous effluent generated from coal carbonization process. PMID:21371822

  4. A new approach in ultrapurification of coal by selective flocculation. Final report

    SciTech Connect

    Moudgil, B.M.

    1992-04-01

    The specific objective of the present investigation is to develop a mathematical and computational model to elicit values of active sites ({phi}) and fractional surface coverage ({theta}) which would yield optimum separation of coal from coal pyrite and coal refuse. Attempts are to be made to select appropriate flocculants and experimental conditions to obtain {phi} and {theta} values as dictated by the theoretical model so as to achieve the desired separation in naturally occurring samples of fine coal. (VC)

  5. Patterning by area selective oxidation

    SciTech Connect

    Nam, Chang-Yong; Kamcev, Jovan; Black, Charles T.; Grubbs, Robert

    2015-12-29

    Technologies are described for methods for producing a pattern of a material on a substrate. The methods may comprise receiving a patterned block copolymer on a substrate. The patterned block copolymer may include a first polymer block domain and a second polymer block domain. The method may comprise exposing the patterned block copolymer to a light effective to oxidize the first polymer block domain in the patterned block copolymer. The method may comprise applying a precursor to the block copolymer. The precursor may infuse into the oxidized first polymer block domain and generate the material. The method may comprise applying a removal agent to the block copolymer. The removal agent may be effective to remove the first polymer block domain and the second polymer block domain from the substrate, and may not be effective to remove the material in the oxidized first polymer block domain.

  6. Coal resources of selected coal beds and zones in the Northern and Central Appalachian Basin

    USGS Publications Warehouse

    Ruppert, Leslie; Tewalt, Susan; Bragg, Linda

    2002-01-01

    The Appalachian Basin is one of the most important coal-producing regions in the world. Bituminous coal has been mined in the basin for the last three centuries, and the cumulative production is estimated at 34.5 billion short tons. Annual production in 1998 was about 452 million short tons; the basin's production is mostly in the northern (32 percent) and central (63 percent) coal regions. The coal is used primarily within the Eastern United States for electric power generation, but some of it is suitable for metallurgical uses. The U.S. Geological Survey (USGS) is completing a National Coal Resource Assessment of five coal-producing regions of the United States, including the Appalachian Basin. The USGS, in cooperation with the State geological surveys of Kentucky, Maryland, Ohio, Pennsylvania, Virginia, and West Virginia, has completed a digital coal resource assessment of five of the top-producing coal beds and coal zones in the northern and central Appalachian Basin coal regions -- the Pittsburgh coal bed, the Upper Freeport coal bed, the Fire Clay and Pond Creek coal zones, and the Pocahontas No. 3 coal bed. Of the 93 billion short tons of original coal in these units, about 66 billion short tons remain.

  7. Surface analysis reveals biogenic oxidation of sub-bituminous coal by Pseudomonas fluorescens.

    PubMed

    Hazrin-Chong, Nur Hazlin; Marjo, Christopher E; Das, Theerthankar; Rich, Anne M; Manefield, Mike

    2014-01-01

    Direct analysis of the colonised surface on coal using attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) revealed the nature of bacteria-mediated oxidation at the coal surface. Unique oxidation peaks generated by the presence of Pseudomonas fluorescens on coal was shown through ATR-FTIR measurements, and ATR-FTIR imaging illustrated that this peak was only observed within the region of coal colonised by bacteria. Contact angle measurements and surface free energy of adhesion calculations showed that the adhesion between P. fluorescens and coal was thermodynamically favourable, and scanning electron microscopy (SEM) exhibited individual cell or monolayer cluster attachment on coal. Furthermore, Gaussian peak fitting of peroxidase-treated coal ATR-FTIR spectra revealed that peroxidase or related enzymes produced by P. fluorescens may be responsible for coal oxidation. This study demonstrated the usefulness and practicality of ATR-FTIR for analysing coal oxidation by P. fluorescens and may well be applied to other microbe-driven modifications of coal for its rapidity and reliability.

  8. Oxidative desulfurization of Tufanbeyli coal by hydrogen peroxide solution

    SciTech Connect

    Guru, M.; Sarioz, B.V.; Cakanyildirim, C.

    2008-07-01

    It is becoming popular to use fossil fuels efficiently since the necessary energy is mostly supplied from fossil fuels. Altough there are high lignite reserves, high sulfur content limits the efficient use of them. In this article, we aimed to convert combustible sulfur in coal to non-combustible sulfate form in the ash by oxidizing it with a hydrogen peroxide solution. The parameters affecting the sulfur conversion were determined to be: hydrogen peroxide concentration, reaction time, mean particle size at constant room temperature and shaking rate. The maximum desulfurization efficiency reached was 74% of the original combustible sulfur with 15% (w/w) hydrogen peroxide solution, 12 hours of reaction time, and 0.25 mm mean particle size.

  9. Wear of Selected Oxide Ceramics and Coatings

    NASA Technical Reports Server (NTRS)

    Miyoshi, K.; Sayir, A.; Farmer, S. C.

    2005-01-01

    The use of oxide ceramics and coatings for moving mechanical components operating in high-temperature, oxidizing environments creates a need to define the tribological performance and durability of these materials. Results of research focusing on the wear behavior and properties of Al2O3/ZrO2 (Y2O3) eutectics and coatings under dry sliding conditions are discussed. The importance of microstructure and composition on wear properties of directionally solidified oxide eutectics is illustrated. Wear data of selected oxide-, nitride-, and carbide-based ceramics and coatings are given for temperatures up to 973K in air.

  10. Coal extraction - environmental prediction

    SciTech Connect

    C. Blaine Cecil; Susan J. Tewalt

    2002-08-01

    To predict and help minimize the impact of coal extraction in the Appalachian region, the U.S. Geological Survey (USGS) is addressing selected mine-drainage issues through the following four interrelated studies: spatial variability of deleterious materials in coal and coal-bearing strata; kinetics of pyrite oxidation; improved spatial geologic models of the potential for drainage from abandoned coal mines; and methodologies for the remediation of waters discharged from coal mines. As these goals are achieved, the recovery of coal resources will be enhanced. 2 figs.

  11. Distribution of trace elements in selected pulverized coals as a function of particle size and density

    USGS Publications Warehouse

    Senior, C.L.; Zeng, T.; Che, J.; Ames, M.R.; Sarofim, A.F.; Olmez, I.; Huggins, Frank E.; Shah, N.; Huffman, G.P.; Kolker, A.; Mroczkowski, S.; Palmer, C.; Finkelman, R.

    2000-01-01

    Trace elements in coal have diverse modes of occurrence that will greatly influence their behavior in many coal utilization processes. Mode of occurrence is important in determining the partitioning during coal cleaning by conventional processes, the susceptibility to oxidation upon exposure to air, as well as the changes in physical properties upon heating. In this study, three complementary methods were used to determine the concentrations and chemical states of trace elements in pulverized samples of four US coals: Pittsburgh, Illinois No. 6, Elkhorn and Hazard, and Wyodak coals. Neutron Activation Analysis (NAA) was used to measure the absolute concentration of elements in the parent coals and in the size- and density-fractionated samples. Chemical leaching and X-ray absorption fine structure (XAFS) spectroscopy were used to provide information on the form of occurrence of an element in the parent coals. The composition differences between size-segregated coal samples of different density mainly reflect the large density difference between minerals, especially pyrite, and the organic portion of the coal. The heavy density fractions are therefore enriched in pyrite and the elements associated with pyrite, as also shown by the leaching and XAFS methods. Nearly all the As is associated with pyrite in the three bituminous coals studied. The sub-bituminous coal has a very low content of pyrite and arsenic; in this coal arsenic appears to be primarily organically associated. Selenium is mainly associated with pyrite in the bituminous coal samples. In two bituminous coal samples, zinc is mostly in the form of ZnS or associated with pyrite, whereas it appears to be associated with other minerals in the other two coals. Zinc is also the only trace element studied that is significantly more concentrated in the smaller (45 to 63 ??m) coal particles.

  12. (Application of selected microorganisms for organic sulfur removal from coal)

    SciTech Connect

    Elmore, B.B.

    1990-06-20

    Research continues on methods for desulfurization of coal using microorganisms. Topics reported on this term include: coal procurement and preparation, microbial removal of pyrite and sulfate, analytical procedures for characterization of total organic sulfur, organic sulfur removal, microbial activity on model coal organosulfur compounds, screening/detection assays, and monitoring of desulfurization activity. (VC)

  13. National coal resource assessment non-proprietary data: Location, stratigraphy, and coal quality for selected tertiary coal in the Northern Rocky Mountains and Great Plains region

    USGS Publications Warehouse

    Flores, Romeo M.; Ochs, A.M.; Stricker, G.D.; Ellis, M.S.; Roberts, S.B.; Keighin, C.W.; Murphy, E.C.; Cavaroc, V.V.; Johnson, R.C.; Wilde, E.M.

    1999-01-01

    One of the objectives of the National Coal Resource Assessment in the Northern Rocky Mountains and Great Plains region was to compile stratigraphic and coal quality-trace-element data on selected and potentially minable coal beds and zones of the Fort Union Formation (Paleocene) and equivalent formations. In order to implement this objective, drill-hole information was compiled from hard-copy and digital files of the: (1) U.S. Bureau of Land Management (BLM) offices in Casper, Rawlins, and Rock Springs, Wyoming, and in Billings, Montana, (2) State geological surveys of Montana, North Dakota, and Wyoming, (3) Wyoming Department of Environmental Quality in Cheyenne, (4) U.S. Office of Surface Mining in Denver, Colorado, (5) U.S. Geological Survey, National Coal Resource Data System (NCRDS) in Reston, Virginia, (6) U.S. Geological Survey coal publications, (7) university theses, and (8) mining companies.

  14. An evaluation of micronized coal reburning for nitrogen oxide emissions reduction in pulverized coal-fired electric utility boilers

    NASA Astrophysics Data System (ADS)

    de Angelo, Joseph Gerard

    Recent increases in the prices of imported fuels and increases in the cost of natural gas have underscored the need to consider other sources of energy for electric production in the United States. Our most abundant fuel source is coal, however the use of coal brings with it a set of environmental problems. This dissertation presents an investigation into the use of micronized coal reburning. This technology may provide a cost-effective solution to the requirements to reduce NOx emissions from pulverized coal-fired electric generating stations. This research effort evaluated the use of micronized coal as a reburning fuel to lower nitrogen oxide emissions from coal-fired boilers. The research effort included: (1) an investigation of all available literature on the subject, (2) planning and supervision of a number of baseline and parametric tests on a full-scale coal fired utility boiler. The testing was carried out on the former NYSEG generating unit, Milliken 1. Milliken Unit 1 is a 150 MW coal-fired electric utility boiler located in Lansing, NY on the eastern shore of Cayuga Lake, (3) development of a model to predict NOx emissions from a coal-fired boiler, and (4) completion of a conceptual design for a micronized coal reburning system. The original plan of the research effort was to include a full-scale micronized coal reburn installation and subsequent modeling and testing. However, in 1998 the deregulation of the electric utility industry in New York caused the focus of the dissertation to be narrowed. The test site, Milliken Station was sold to another entity, and the installation of the micronized coal reburn system was cancelled. The following conclusions were drawn from the research: (1) Testing showed that nitrogen oxide production was significantly influenced by changes in controllable boiler operating parameters. (2) The predictive model for baseline nitrogen oxide production was fairly accurate in estimating NOx emissions. The model had an average

  15. Quality of selected coal seams from Indiana: Implications for carbonization

    USGS Publications Warehouse

    Walker, R.; Mastalerz, Maria; Padgett, P.

    2001-01-01

    The chemical properties of two high-volatile bituminous coals, the Danville Coal Member of the Dugger Formation and the Lower Block Coal Member of the Brazil Formation from southern Indiana, were compared to understand the differences in their coking behavior. It was determined that of the two, the Lower Block has better characteristics for coking. Observed factors that contribute to the differences in the coking behavior of the coals include carbon content, organic sulfur content, and oxygen/carbon (O/C) ratios. The Lower Block coal has greater carbon content than the Danville coal, leading to a lower O/C ratio, which is more favorable for coking. Organic sulfur content is higher in the Lower Block coal, and a strong correlation was found between organic sulfur and plasticity. The majority of the data for both seams plot in the Type III zone on a van Krevelen diagram, and several samples from the Lower Block coal plot into the Type II zone, suggesting a perhydrous character for those samples. This divergence in properties between the Lower Block and Danville coals may account for the superior coking behavior of the Lower Block coal. ?? 2001 Elsevier Science B.V. All rights reserved.

  16. Cleaning of China high sulfur coals by selective dispersion and flocculation

    SciTech Connect

    Wang Li; Liu Zechang; Liu Zhenxue

    1997-12-31

    A process for removing pyritic sulfur from high sulfur coals by selective dispersion and flocculation has been conceptually developed and tested in China. The tentative tests on China high sulfur coals have shown that this coal cleaning process can be very efficient in coal desulfurization, provided the process parameters are properly optimized. While acquiring high coal recovery, the total sulfur rejection with four kinds of coals normally falls in the range 57% to 71% by one-step reverse flocculation, and within the range 40% to 59% by one-step normal flocculation process. This cleaning process presents a promising approach for the removal of pyrite particles from coal fines suspensions. Most of the results presented in this paper are preliminary in nature, and further research is being carried out.

  17. Protocols for the selective cleavage of carbon-sulfur bonds in coal. Final technical report, September 1, 1992--December 31, 1993

    SciTech Connect

    Bausch, M.

    1993-12-31

    Results of research pertaining to chemical reactions that aim to selectively cleave C-S bonds in model compounds as well as Illinois coal are summarized. Chemical reactions that result in carbon-sulfur bond cleavage are an essential aspect of any protocol designed to remove organic sulfur from coal. In the second year of the project ``Protocols for the Selective Cleavage of Carbon-Sulfur Bonds in Coal`` investigations of reactions in which organic sulfur-containing coal model compounds are subjected to different conditions of temperature, solvent mixtures, reagents, and radiation have been completed. A series of reactions have been undertaken in which physically cleaned Illinois coal has been subjected to many of the same reaction conditions that were shown, via the use of model sulfides, to result in substantial C-S bond cleavage and or sulfur oxidation. Therefore, summarized in this final report are results of the investigations of the photooxidation reactions of coal model sulfones and sulfides; the photolytic desulfurization of coal; and various other topics, including a summary of endeavors aimed at initiating C-S bond cleavage reactions using oxidation/chlorination/desulfurization protocols, and various tellurium reagents.

  18. Protocols for the selective cleavage of carbon-sulfur bonds in coal. Interim final technical report, September 1, 1992--August 31, 1993

    SciTech Connect

    Bausch, M.

    1993-12-31

    This report presents results of research pertaining to chemical reactions that aim to selectively cleave C-S bonds in model compounds as well as Illinois coal. Chemical reactions that result in carbon-sulfur bond cleavage are an essential aspect of any protocol designed to remove organic sulfur from coal. In the second year of the project {open_quotes}Protocols for the Selective Cleavage of Carbon-Sulfur Bonds in Coal, the author has completed investigations of reactions in which organic sulfur-containing coal model compounds are subjected to different conditions of temperature, solvent mixtures, reagents, and radiation. He has also undertaken a series of reactions in which physically cleaned Illinois coal has been subjected to many of the same reaction conditions that were shown, via the use of model sulfides, to result in substantial C-S bond cleavage and or sulfur oxidation. Therefore, summarized in this interim final report are results of the investigations of the photooxidation reactions of coal model sulfones and sulfides; the photolytic desulfurization of coal; and various other topics, including a summary of the endeavors aimed at initiating C-S bond cleavage reactions using oxidation/chlorination/desulfurization protocols, and various tellurium reagents. Important experiments remain to be completed on this project; therefore, efforts in these areas will continue through the end of calendar year 1993.

  19. Oxide-supported metal carbonyls: novel catalysts for the liquefaction of coal. Final technical report

    SciTech Connect

    Melson, G.A.

    1985-01-01

    Coal liquefaction, hydrodesulfurization (HDS), and hydrodenitrogenation (HDN) catalysts have been investigated increasingly in recent years because of the need to understand how to develop more selective and stable materials for coal utilization. One catalyst that has been used extensively for HDS and subjected to numerous characterization and model reaction studies is Co-Mo/Al/sub 2/O/sub 3/. In these studies, the catalyst preparation technique has usually involved the incipient-wetness impregnation of ..gamma..-Al/sub 2/O/sub 3/ with ammonium molybdates and cobalt nitrates. Such a technique leads to a variety of surface species, bulk-like and monolayer forms, which have been described and can be controlled by alterations in the preparation techniques and materials. However, certain structural and chemical factors of the catalysts, e.g., Co and Mo reducibility and dispersion or surface speciation at low and high metal concentrations, seem to be independent of such alterations. To investigate whether these factors can be affected by preparation techniques and to develop oxide-supported, metal catalysts having controlled metal dispersions and speciation, a catalyst preparation technique using metal carbonyls with an extraction process to metal-load oxide supports has been developed (J.E. Crawford, G.A. Melson, L.E. Makovsky, F.R. Brown, J. Catal., 83: 454 (1983)). This report discusses the surface and bulk characterization, and presents initial HDS and liquefaction results, for these catalysts. 7 refs., 4 figs., 1 tab.

  20. Process and analytical studies of enhanced low severity co-processing using selective coal pretreatment

    SciTech Connect

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

    1991-12-01

    The findings in the first phase were as follows: 1. Both reductive (non-selective) alkylation and selective oxygen alkylation brought about an increase in liquefaction reactivity for both coals. 2. Selective oxygen alkylation is more effective in enhancing the reactivity of low rank coals. In the second phase of studies, the major findings were as follows: 1. Liquefaction reactivity increases with increasing level of alkylation for both hydroliquefaction and co-processing reaction conditions. 2. the increase in reactivity found for O-alkylated Wyodak subbituminous coal is caused by chemical changes at phenolic and carboxylic functional sites. 3. O-methylation of Wyodak subbituminous coal reduced the apparent activation energy for liquefaction of this coal.

  1. Removal of sulfur and chlorine from Illinois coals by wet-grinding and selective flocculation

    SciTech Connect

    Chou, C.L.

    1999-07-01

    A coal-cleaning method for removing sulfur and chlorine from Illinois Basin coals was developed. The method includes four steps: (1) crushing raw coal to {minus}10 mesh, (2) using a concentrating table to remove pyrite and other minerals, (3) wet-grinding coal to an ultrafine particle size to liberate coal from pyrite and other minerals, and (4) conducting selective flocculation to separate coal from mineral particles and chlorine-containing water. A sample of Illinois Basin coal IBC-106 (9.0% ash and 3.77% sulfur) was ground to {minus}10 mesh and separated into five fractions on a concentrating table. The pyritic sulfur content decreased from 1.85% in feed coal to 1.49%, 0.85%, and 0.82% in clean, fine, and overflow fractions, respectively. Wet-grinding and selective flocculation tests were conducted on another sample of Illinois Basin coal IBC-105 (18.6% ash and 4.55% sulfur). The coal was ground in a stirred ball mill to generate a coal slurry with a particle size distribution of 90% <19 micrometer. The slurry was dispersed to make a complete suspension. Sodium metaphosphate was added as a dispersant. Various polymeric flocculants were tested to determine the selective flocculation performance of each. The acidity of the slurry (pH) and the flocculant dosage are critical in selective flocculation tests. When flocculant Calgon WCL-762 was used, the ash content decreased from 18.6% to 8.1% (56% reduction) in a single-stage flocculation process, and to 5.7% (69% reduction) in a two-stage process. Chlorine removal from coal was investigated on a high-chlorine coal sample IBC-109 (8.2% ash, 1.13% sulfur, and 0.42% chlorine). Wet-grinding the coal to 90% <20 micrometer, and subsequently dewatering the slurry by selective flocculation reduced the chlorine content from 0.42% to between 0.11% and 0.15% (64% to 74% reduction). In addition, ash content was reduced from 8.2% to between 4.0% and 5.4% (34% to 51% reduction) and pyritic sulfur content from 0.50% to between 0

  2. Sequential solvent extraction for forms of antimony in five selected coals

    USGS Publications Warehouse

    Qi, C.; Liu, Gaisheng; Kong, Y.; Chou, C.-L.; Wang, R.

    2008-01-01

    Abundance of antimony in bulk samples has been determined in five selected coals, three coals from Huaibei Coalfield, Anhui, China, and two from the Illinois Basin in the United States. The Sb abundance in these samples is in the range of 0.11-0.43 ??g/g. The forms of Sb in coals were studied by sequential solvent extraction. The six forms of Sb are water soluble, ion changeable, organic matter bound, carbonate bound, silicate bound, and sulfide bound. Results of sequential extraction show that silicate-bound Sb is the most abundant form in these coals. Silicate- plus sulfide-bound Sb accounts for more than half of the total Sb in all coals. Bituminous coals are higher in organic matterbound Sb than anthracite and natural coke, indicating that the Sb in the organic matter may be incorporated into silicate and sulfide minerals during metamorphism. ?? 2008 by The University of Chicago. All rights reserved.

  3. Sequential solvent extraction for forms of antimony in five selected coals

    SciTech Connect

    Qi, C.C.; Liu, G.J.; Kang, Y.; Chou, C.L.; Wang, R.W.

    2008-03-15

    Abundance of antimony in bulk samples has been determined in five selected coals, three coals from Huaibei Coalfield, Anhui, China, and two from the Illinois Basin in the United States. The Sb abundance in these samples is in the range of 0.11-0.43 {mu} g/g. The forms of Sb in coals were studied by sequential solvent extraction. The six forms of Sb are water soluble, ion changeable, organic matter bound, carbonate bound, silicate bound, and sulfide bound. Results of sequential extraction show that silicate-bound Sb is the most abundant form in these coals. Silicate-plus sulfide-bound Sb accounts for more than half of the total Sb in all coals. Bituminous coals are higher in organic matter bound Sb than anthracite and natural coke, indicating that the Sb in the organic matter may be incorporated into silicate and sulfide minerals during metamorphism.

  4. Reactive molecular dynamics simulations of the initial stage of brown coal oxidation at high temperatures

    NASA Astrophysics Data System (ADS)

    Yan, Guochao; Zhang, Zhiqiang; Yan, Kefeng

    2013-01-01

    To investigate the detailed mechanisms for brown coal oxidation at high temperatures, a ReaxFF reactive forcefield was used to perform a series of molecular dynamics simulations from 1000 K to 2500 K. Analyses indicated that the chemical system tend to be more reactive with increasing temperature. It was found that the oxidation process of brown coal primarily initiates from hydrogen abstraction reactions by O2 and related oxygenated radicals from phenolic hydroxyl groups, methyl groups, especially carboxyl groups in lower temperature to form peroxygen species, or by either thermal decomposition of brown coal backbone in higher temperature. These peroxygen species usually could chemically adsorb on the C-centered radicals of brown coal backbone. The weak O-O bond in peroxygen makes them easier to break into oxygenated radical, which could also chemically adsorb on the C-centred radical to form hydroxyl group and other oxygenated compounds. In the oxidation process of brown coal, the decomposition and oxidation of aliphatic chain is easier than aromatic ring. The chemisorption of peroxygen radical induces the breakage of aromatic ring and accelerates the depth oxidation of brown coal. An increasing number of products are observed with increasing temperature.

  5. Selective flocculation of pyrite and/or silica in the presence of coal

    SciTech Connect

    Venkatadri, R.; Markuszevski, R.; Wheelock, T.D. ); Walters, A.B. )

    1988-06-01

    Two cationic surfactants, Arquad T-50 and Duomac T, were investigated as possible selective flocculants or coagulants for iron pyrite or silica particles in the presence of particles of eastern bituminous coal. Although these surfactants were adsorbed by all three materials, they were found to promote the flocculation of pyrite and silica much more than the flocculation of coal when the solid materials were flocculated separately. In subsequent selective flocculation tests involving binary mixtures of the solid components, a good separation of coal and silica was achieved with Duomac T by agitating the flocculating suspension for a prolonged time. However, the separation of coal and pyrite proved more elusive. While some separation was achieved with Arquad T-50 because pyrite was flocculated more extensively than coal, the separation was marginal at best.

  6. Use of metal hydrous titanium oxide catalysts to enhance coal tar yield via hydropyrolysis

    SciTech Connect

    Klavetter, E.A.; Stephens, H.P.; Dosch, R.G.

    1990-01-01

    Catalytic hydropyrolysis experiments performed in this project on several US and UK coals have established that tar yields in excess of 70% (daf basis) and conversions (100%-char) in excess of 80% can be achieved from bituminous coals containing 80--84% dmmf carbon using hydrous titanium oxide (HTO) catalysts with low concentrations of active metals. Total conversion approaches the reactive maceral contents for these coals. Previously performed two-stage catalytic hydropyrolysis experiments have demonstrated that high yields of liquid products with high H/C ratios, low heteroatom contents, and a significant concentration of light naphtha can be achieved. The objectives of this research are to determine suitable methods for catalyzing the hydropyrolysis process and to investigate the reactions and mechanisms responsible for the high conversion of coal materials to distillable liquids via direct catalytic hydropyrolysis. Recently developed hydrous titanium oxide (HTO)-supported catalysts have received encouraging results in direct coal liquefaction applications. Results of hydropyrolysis experiment using Mo and Pd HTO catalysts coated directly onto the coal are presented here and compared with results from experiments using uncatalyzed coal samples and using a dispersed MoS{sub 2} catalyst. The effect of coal rank, active metals concentration, dispersion method, and metal type are discussed. 9 refs., 6 figs., 2 tabs.

  7. Air/water oxidative desulfurization of coal and sulfur-containing compounds

    NASA Astrophysics Data System (ADS)

    Warzinski, R. P.; Freidman, S.; LaCount, R. B.

    1981-02-01

    Air/water Oxydesulfurization has been demonstrated in autoclave experiments at the Pittsburgh Energy Technology Center for various coals representative of the major U. S. coal basins. The applicability at present of this treatment for producing an environmentally acceptable coal has been restricted by recently proposed SO2 emission standards for utility boilers. The product would, however, be attractive to the many smaller industrial coal users who cannot afford to operate and maintain flue gas desulfurization systems. It is also possible that the utility industry could realize a benefit by using chemically cleaned coal with partial flue gas scrubbing. The higher cost of the cleaned coal would be offset by the reduction in capital and operating costs resulting from decreased FGD requirements. The susceptibility of sulfur in coal to oxidative removal varies with the nature of the sulfur-containing species. The inorganic sulfur compounds, primarily pyrite, marcasite, and iron sulfate, are more amenable to treatment than the organically bound sulfur which exhibits varying degrees of resistance depending on its chemical environment. Air/water Oxydesulfurization consistently removes in excess of 90 percent of the pyritic sulfur; the extent and efficiency of organic sulfur removal however, depends on the type of coal and severity of treatment used. In general, the organic sulfur of the higher rank coals exhibits more resistance to treatment than that of the lower rank coals; however, the accompanying heating value is greater for the latter. Similar treatment of sulfur-containing model compounds further illustrates the relative susceptibilities of different chemical species to oxidation. Application of these data to the understanding of the complex chemistry involved in the treatment of coal is a preliminary step toward improving the efficiency of Oxydesulfurization.

  8. Fossil resin flotation from coal by selective coagulation and depression of coal

    SciTech Connect

    Miller, J.D.; Yi, Y.

    1990-02-27

    This patent describes a method for separating minute resin particles from a slurry mixture of minute resin particles and minute coal particles. It comprises: adjusting the pH of the slurry mixture of minute resin particles and minute coal particles to above about 12 and subjecting the pH adjusted slurry mixture of particles to froth flotation in the presence of a frothing agent, to produce a froth fraction enriched with respect to the minute resin particles.

  9. NOVEL MERCURY OXIDANT AND SORBENT FOR MERCURY EMISSIONS CONTROL FROM COAL-FIRED POWER PLANTS

    EPA Science Inventory

    The authors have successfully developed novel efficient and cost-effective sorbent and oxidant for removing mercury from power plant flue gases. These sorbent and oxidant offer great promise for controlling mercury emissions from coal-fired power plants burning a wide range of c...

  10. Gas cleaning and hydrogen sulfide removal for COREX coal gas by sorption enhanced catalytic oxidation over recyclable activated carbon desulfurizer.

    PubMed

    Sun, Tonghua; Shen, Yafei; Jia, Jinping

    2014-02-18

    This paper proposes a novel self-developed JTS-01 desulfurizer and JZC-80 alkaline adsorbent for H2S removal and gas cleaning of the COREX coal gas in small-scale and commercial desulfurizing devices. JTS-01 desulfurizer was loaded with metal oxide (i.e., ferric oxides) catalysts on the surface of activated carbons (AC), and the catalyst capacity was improved dramatically by means of ultrasonically assisted impregnation. Consequently, the sulfur saturation capacity and sulfur capacity breakthrough increased by 30.3% and 27.9%, respectively. The whole desulfurizing process combined selective adsorption with catalytic oxidation. Moreover, JZC-80 adsorbent can effectively remove impurities such as HCl, HF, HCN, and ash in the COREX coal gas, stabilizing the system pressure drop. The JTS-01 desulfurizer and JZC-80 adsorbent have been successfully applied for the COREX coal gas cleaning in the commercial plant at Baosteel, Shanghai. The sulfur capacity of JTS-01 desulfurizer can reach more than 50% in industrial applications. Compared with the conventional dry desulfurization process, the modified AC desulfurizers have more merit, especially in terms of the JTS-01 desulfurizer with higher sulfur capacity and low pressure drop. Thus, this sorption enhanced catalytic desulfurization has promising prospects for H2S removal and other gas cleaning.

  11. Gas cleaning and hydrogen sulfide removal for COREX coal gas by sorption enhanced catalytic oxidation over recyclable activated carbon desulfurizer.

    PubMed

    Sun, Tonghua; Shen, Yafei; Jia, Jinping

    2014-02-18

    This paper proposes a novel self-developed JTS-01 desulfurizer and JZC-80 alkaline adsorbent for H2S removal and gas cleaning of the COREX coal gas in small-scale and commercial desulfurizing devices. JTS-01 desulfurizer was loaded with metal oxide (i.e., ferric oxides) catalysts on the surface of activated carbons (AC), and the catalyst capacity was improved dramatically by means of ultrasonically assisted impregnation. Consequently, the sulfur saturation capacity and sulfur capacity breakthrough increased by 30.3% and 27.9%, respectively. The whole desulfurizing process combined selective adsorption with catalytic oxidation. Moreover, JZC-80 adsorbent can effectively remove impurities such as HCl, HF, HCN, and ash in the COREX coal gas, stabilizing the system pressure drop. The JTS-01 desulfurizer and JZC-80 adsorbent have been successfully applied for the COREX coal gas cleaning in the commercial plant at Baosteel, Shanghai. The sulfur capacity of JTS-01 desulfurizer can reach more than 50% in industrial applications. Compared with the conventional dry desulfurization process, the modified AC desulfurizers have more merit, especially in terms of the JTS-01 desulfurizer with higher sulfur capacity and low pressure drop. Thus, this sorption enhanced catalytic desulfurization has promising prospects for H2S removal and other gas cleaning. PMID:24456468

  12. Influence of Combined Water in Coal on Pre-reduction of Iron Oxide with Coal Carbonization Gas in Low, Middle and High Volatile Matter Coal

    NASA Astrophysics Data System (ADS)

    Inoue, Noriyoshi; Usui, Tateo

    Volatile matter, which occupies more than 20 mass% in non-coking coal, is not utilized when the coal is fed directly into the smelting furnace. Its presence may even cause adverse effects in the operation. Therefore, the fundamental study on pre-reduction of iron oxide was carried out in order to investigate the conditions for efficient use of volatile matter in an iron bath smelting reduction total process. The final fractional reduction, F, was calculated from the loss in weight of pellets after reduction. Presence of combined water in coal affected F and caused a decrease in F at higher temperatures. However, when the combined water was removed from coal, F increased. In each coal, when the combined water was removed from volatile matter, F increased linearly from about 0.08 to 0.20 at the reduction temperatures from 773K up to 1073 K, beyond which F increased more than the linear relation, such as F about 0.30 at 1173 K and 0.40 at 1273 K. This may be due to caused by the contribution of hydrocarbons in the reduction reaction at high temperatures.

  13. 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.

  14. An EPR spin probe method for characterizing changes in the accessible regions of coal upon oxidation

    SciTech Connect

    Sady, W.; Kispert, L.D.; Spears, D.R.

    1992-01-01

    Eight Argonne Premium Coal Samples (APCS) were weathered in air and the structural and chemical changes that upon swelling with toluene and pyridine were, examined by an EPR spin probe method developed in this laboratory. Under mild oxidation conditions and swelling with toluene large structural changes were observed for lignite (Beulah-Zap) which suggested the collapse of the coal structure. This did not occur for higher rank coal. Upon oxidation and swelling with toluene and pyridine an increase occurred in the amino substituted spin probe concentration for coals with the carbon percent above 80%. A maximum was found for the creation of 5 {Angstrom} diameter pores upon swelling with pyridine at 85% C.

  15. An EPR spin probe method for characterizing changes in the accessible regions of coal upon oxidation

    SciTech Connect

    Sady, W.; Kispert, L.D.; Spears, D.R.

    1992-09-01

    Eight Argonne Premium Coal Samples (APCS) were weathered in air and the structural and chemical changes that upon swelling with toluene and pyridine were, examined by an EPR spin probe method developed in this laboratory. Under mild oxidation conditions and swelling with toluene large structural changes were observed for lignite (Beulah-Zap) which suggested the collapse of the coal structure. This did not occur for higher rank coal. Upon oxidation and swelling with toluene and pyridine an increase occurred in the amino substituted spin probe concentration for coals with the carbon percent above 80%. A maximum was found for the creation of 5 {Angstrom} diameter pores upon swelling with pyridine at 85% C.

  16. Oxidative Activity of Heated Coal Affected by Antypirogens

    NASA Astrophysics Data System (ADS)

    Torosyan, V. F.; Torosyan, E. S.; Borovikov, I. F.; Yakutova, V. A.

    2016-04-01

    The effect of antypirogens on chemical activity of heated coal is studied. It is proved that ammonium sulfate, calcium phosphate, calcium chloride, calcium nitrate and acid fluoride are the most effective antypirogens.

  17. Palynology of selected coal beds in the proposed Pennsylvanian System stratotype in West Virginia

    USGS Publications Warehouse

    Kosanke, Robert M.

    1984-01-01

    ) Wilson and Venkatachala, Schopfites dimorphus Kosanke, and Thymospora thiessenii (Kosanke) Wilson and Venkatachala. Some of the range zones are relatively short and extremely useful for correlation studies. For example, in the Charleston Sandstone, T. pseudothiessenii (Kosanke) Wilson and Venkatachala is present in the Upper No.5 Block coal (upper bench) and the No.6 Block coal, whereas Schopfites dimorphus Kosanke is restricted to the No.6 Block coal. Thymospora thiessenii (Kosanke) Wilson and Venkatachala is not restricted to the Pittsburgh No.8 coal, but it is the only coal known in which this taxon is so dominant (more than 70 percent of the palynomorph assemblage). This preliminary report has provided a framework for the correlation of a selected number of coals occurring in Ohio and eastern Kentucky with those of the proposed Pennsylvanian System stratotype of West Virginia. In other studies, additional samples from the stratotype would be examined for ultimate correlation with rocks of Pennsylvania and in adjacent States and elsewhere.

  18. Novel microorganism for selective separation of coal from ash and pyrite. Fifth quarterly technical progress report, October 1--December 31, 1994

    SciTech Connect

    Misra, M.; Smith, R.W.; Raichur, A.M.

    1994-12-31

    The objective of this project is to study the effectiveness of a novel hydrophobic microorganism, Mycobacterium phlei (M. phlei), for the selective flocculation of coal from pyrite and ash forming minerals. During the reporting period, the flocculation efficiencies of Illinois No.6 coal with M. phlei and with polymeric flocculants such as polyethylene oxide and polyacrylamide were investigated. Results indicated that good flocculation efficiencies were obtained with M. phlei as opposed to synthetic flocculants at an acidic pH value. Floc separation studies were conducted using column flotation. It was found that very good recovery of coal with a high rejection of pyrite and ash could be obtained using M. phlei when compared with synthetic flocculants. DLVO calculations for coal/M. phlei interface showed that minimum interaction energy occurs at acidic pH values thus facilitating the adhesion of M. phlei. A good correlation between the interaction energy and adhesion, contact angle and flocculation results were noticed.

  19. Toxic Substances From Coal Combustion - Phase I Coal Selection and Chaacterization

    SciTech Connect

    A. Kolker; A. Sarofim; C.A. Palmer; C.L. Senior; F.E. Huggins; G.P. Huffman; I. Olmez; N. Shah; R. Finkelman; S. Crowley; T. Zeng

    1998-07-16

    The Clean Air Act Amendments of 1990 identify a number of hazardous air pollutants (HAPs) as candidates for regulation. Should regulations be imposed on HAP emissions from coal-fired power plants, a sound understanding of the fundamental principles controlling the formation and partitioning of toxic species during coal combustion will be needed. Over the past decade, a large database identifying the partitioning and emitted concentrations of several toxic metals on the list of HAPs has been developed. Laboratory data have also been generated to help define the general behavior of several elements in combustion systems. These data have been used to develop empirical and probabalistic models to predict emissions of trace metals from coal-fired power plants. While useful for providing average emissions of toxic species, these empirically based models fail when extrapolated beyond their supporting database. This represents a critical gap; over the coming decades, new fuels and combustion systems will play an increasing role in our nation's power generation system. For example, new fuels, such as coal blends or beneficiated fuels, new operating conditions, such as low-NO burners or staged combustion, or new power x systems, for example, those being developed under the DoE sponsored Combustion 2000 programs and integrated gasification combined cycle (IGCC) systems, are all expected to play a role in power generation in the next century. The need for new predictive tools is not limited to new combustion systems, however. Existing combustion systems may have to employ controls for HAPs, should regulations be imposed. Testing of new control methods, at pilot and full scale, is expensive. A sound under-standing of the chemical transformations of both organic and inorganic HAPs will promote the development of new control methods in a cost-effective manner. To ensure that coal-fired power generation proceeds in an environmentally benign fashion, methods for the prediction and

  20. Genetic and oxidative damage of peripheral blood lymphocytes in workers with occupational exposure to coal.

    PubMed

    Rohr, Paula; Kvitko, Kátia; da Silva, Fernanda R; Menezes, Ana Paula Simões; Porto, Carem; Sarmento, Merielen; Decker, Natália; Reyes, Juliana M; Allgayer, Mariangela da C; Furtado, Tatiane Chao; Salvador, Mirian; Branco, Catia; da Silva, Juliana

    2013-12-12

    Coal is an important fossil fuel used to generate energy. Coal dust is constituted primarily of hydrocarbons and metals. During coal extraction, large quantities of coal dust particles are emitted, contributing to environmental pollution. Coal miners are constantly exposed to coal dust and its derivatives. The goal of this study was to evaluate the potential genotoxic effects of coal and oxidative stress in individuals from Candiota who were exposed to coal as part of their occupation. The comet assay and micronucleus (MN) test were used to assess these effects. This study involved 128 male participants of whom 71 reported work that included exposure to coal (exposed group) and 57 reported working at different jobs (unexposed group). The exposed group had a significantly increased damage index and damage frequency, as assessed using the comet assay, and increased MN and nucleoplasmic bridge frequencies, as assessed using the MN assay, compared with unexposed individuals. Significant and positive correlations between MN frequencies in the lymphocytes and buccal cells of control and exposed individuals were observed. The exposed individuals presented lower average levels of thiobarbituric acid reactive substances (TBARS) and catalase activity (CAT), while the mean superoxide dismutase activity (SOD) levels were higher in this group. The exposed group also had higher hematocrit levels. No correlation between DNA damage and inorganic elements, as identified using PIXE, was found; however, there was a correlation between the damage index and zinc. The evidence that exposure to coal and its derivatives presents a genetic hazard demonstrates the need for protective measures and educational programs for coal miners.

  1. Selective thermal oxidation of hydrocarbons in zeolites by oxygen

    DOEpatents

    Frei, Heinz; Blatter, Fritz; Sun, Hai

    2000-01-01

    A process for selective thermal oxidation of hydrocarbons adsorbed onto zeolite matrices. A highly selective thermal oxidation of unsubstituted or alkyl substituted alkanes, alkenes, aromatics and cycloalkyls is carried out in solvent free zeolites under dark thermal conditions. The process oxidizes hydrocarbons almost completely selectively without substantial production of byproducts.

  2. Occurrence and activity of iron and sulfur-oxidizing microorganisms in alkaline coal strip mine spoils

    SciTech Connect

    Olson, G.J.; McFeters, G.A.; Temple, K.L.

    1980-03-01

    Spoils samples collected from a coal strip mine in southeastern Montana were examined for populations and activities of iron- and sulfur-oxidizing bacteria. Spoils examined were of three types: (1) acidic pyrite-rich waste coal, (2) oxidation halo material, and (3) alkaline, which was the most widespread type. Bacterial numbers, sulfur oxidation, and /sup 14/CO/sub 2/ uptake activity declined to low levels in the summer when spoils were dry. Even in wetter spring months pyritic spoils contained relatively low numbers of acidophilic iron- and sulfur-oxidizing bacteria, probably indicative of water stress since the same spoils incubated with excess water or dilute mineral salts showed considerably greater bacterial numbers and activity. Certain wells in coal and spoils aquifers contained substantial populations of iron-oxidizing acidophilic bacteria. However, these wells were always of alkaline or neutral pH indicating that bacterial pyrite oxidation occurred in localized areas where groundwaters contacted either replaced spoils or coal which contained either pyrite or other metal sulfides. Bacterial activity may contribute to trace metal and sulfate leaching which occur in the area.

  3. Occurrence and activity of iron- and sulfur-oxidizing microorganisms in alkaline coal strip mine spoils

    SciTech Connect

    Olson, G.J.; McFeters, G.A.; Temple, K.L.

    1981-01-01

    Spoils samples collected from a coal strip mine in southeastern Montana were examined for populations and activities of iron-and sulphur-oxidizing bacteria. Spoils examined were of three types: (a) acidic pyrite-rich waste coal; (b) oxidation halo material; and (c) alkaline material, which was the most widespread type. Bacterial numbers, sulphur oxidation and /SUP/1/SUP/4CO/SUB/2 uptake activity declined to low levels in the summer when spoils were dry. Even in wetter spring months pyritic spoils contained relatively low numbers of acidophilic iron- and sulphur-oxidizing bacteria, probably indicative of water stress since the same spoils incubated with excess water or dilute mineral salts showed considerably greater bacterial numbers and activity. Certain wells in coal and spoils aquifers contained substantial populations of iron-oxidizing acidophilic bacteria. However, these wells were always of alkaline or neutral pH, indicating that bacterial pyrite oxidation occurred where groundwaters contacted either replaced spoils of coal that contained pyrite or other metal sulphides. Bacterial activity may contribute to trace metal and sulphate leaching in the area. (27 refs.)

  4. Occurrence and activity of iron- and sulfur-oxidizing microorganisms in alkaline coal strip mine spoils.

    PubMed

    Olson, G J; McFeters, G A; Temple, K L

    1981-03-01

    Spoils samples collected from a coal strip mine in southeastern Montana were examined for populations and activities of iron- and sulfur-oxidizing bacteria. Spoils examined were of three types: (a) acidic pyrite-rich waste coal, (b) oxidation halo material, and (c) alkaline material, which was the most widespread type. Bacterial numbers, sulfur oxidation, and(14)CO2 uptake activity declined to low levels in the summer when spoils were dry. Even in wetter spring months pyritic spoils contained relatively low numbers of acidophilic iron- and sulfur-oxidizing bacteria, probably indicative of water stress since the same spoils incubated with excess water or dilute mineral salts showed considerably greater bacterial numbers and activity. Certain wells in coal and spoils aquifers contained substantial populations of iron-oxidizing acidophilic bacteria. However, these wells were always of alkaline or neutral pH, indicating that bacterial pyrite oxidation occurred where groundwaters contacted either replaced spoils or coal that contained pyrite or other metal sulfides. Bacterial activity may contribute to trace metal and sulfate leaching in the area.

  5. Determination of selected elements in whole coal and in coal ash from the eight argonne premium coal samples by atomic absorption spectrometry, atomic emission spectrometry, and ion-selective electrode

    USGS Publications Warehouse

    Doughten, M.W.; Gillison, J.R.

    1990-01-01

    Methods for the determination of 24 elements in whole coal and coal ash by inductively coupled argon plasma-atomic emission spectrometry, flame, graphite furnace, and cold vapor atomic absorption spectrometry, and by ion-selective electrode are described. Coal ashes were analyzed in triplicate to determine the precision of the methods. Results of the analyses of NBS Standard Reference Materials 1633, 1633a, 1632a, and 1635 are reported. Accuracy of the methods is determined by comparison of the analysis of standard reference materials to their certified values as well as other values in the literature.

  6. Cooperative research program in coal liquefaction

    SciTech Connect

    Huffman, G.P.; Sendlein, L.V.A.

    1991-01-01

    This report is a coordinated effort of the Consortium for Fossil Fuel Liquefaction Science. The topics concerning coal liquefaction discussed are: sulfate promoted metal oxides as direct coal liquefaction catalysts; low temperature depolymerization and liquefaction of premium R.S. coal samples; construction of continuous flow-through gas reactor for liquefaction investigations; generic structural characterization and liquefaction research; macerals, model compounds and iron catalyst dispersion; coal structure/liquefaction yield correlation by means of advanced NMR techniques; GC/MS of model compound mixtures; catalytic cracking, hydrogenation and liquefaction of coals under milder conditions; ENDOR investigations of coal liquefaction under mild conditions; catalytic dehydrogenation of model compounds in relation to direct coal liquefaction; surface characterization of catalyst added coal samples; computational chemistry of model compounds and molecular fragments of relevance to coal liquefaction; chemical characterization and hydrogenation reactions of single coal particles; thermolytic cleavage of selected coal-related linkages at mild temperatures; solvent sorption and FTIR studies on the effect of catalytic depolymerization reactions in coal; bioprocessing of coal; chemical routes to breaking bonds; novel liquefaction concepts cyclic olefins: novel new donors for coal liquefaction; better hydrogen transfer in coal liquefaction; catalytic hydropyrolysis and energized extraction of coals; gallium catalyst in mild coal liquefaction; potential of temperature microscope in coal liquefaction; evaluation of nitride catalysts for hydrotreatment and coal liquefaction; coprocessing and coal liquefaction with novel catalysts.

  7. Selective ion penetration of graphene oxide membranes.

    PubMed

    Sun, Pengzhan; Zhu, Miao; Wang, Kunlin; Zhong, Minlin; Wei, Jinquan; Wu, Dehai; Xu, Zhiping; Zhu, Hongwei

    2013-01-22

    The selective ion penetration and water purification properties of freestanding graphene oxide (GO) membranes are demonstrated. Sodium salts permeated through GO membranes quickly, whereas heavy-metal salts infiltrated much more slowly. Interestingly, copper salts were entirely blocked by GO membranes, and organic contaminants also did not infiltrate. The mechanism of the selective ion-penetration properties of the GO membranes is discussed. The nanocapillaries formed within the membranes were responsible for the permeation of metal ions, whereas the coordination between heavy-metal ions with the GO membranes restricted the passage of the ions. Finally, the penetration processes of hybrid aqueous solutions were investigated; the results revealed that sodium salts can be separated effectively from copper salts and organic contaminants. The presented results demonstrate the potential applications of GO in areas such as barrier separation and water purification.

  8. Removal of ash, sulfur, and trace elements of environmental concern from eight selected Illinois coals

    USGS Publications Warehouse

    Demir, I.

    1998-01-01

    Release analysis (RA) and float-sink (F-S) data were generated to assess the beneficiation potential of washed coals from selected Illinois coal preparation plants through the use of advanced physical cleaning at -60 mesh size. Generally, the F-S process removed greater amounts of ash, sulfur, and trace elements of environmental concern from the coals than the RA process, indicating that the cleanability of Illinois coals by advanced methods can be estimated best by F-S testing. At an 80%-combustibles recovery, the ash yield in the clean F-S products decreased by 47-75%, relative to the parent coals. Average decreases for the elements As(67%), Cd(78%), Hg(73%), Mn(71%), and P(66%) exceeded the average decrease for ash yield (55%). Average decreases for other elements were: Co(31%), Cr(27%), F(39%), Ni(25%), Pb(50%), S(28%), Sb(20%), Se(39), Th(32%), and U(8%). Only Be was enriched (up to 120%) in the clean products relative to the parent coals. These results suggested that the concentration of elements with relatively high atmospheric mobilities (As, Cd, F, Hg, Pb, and Se) during coal combustion can be reduced substantially in Illinois coals through the use of advanced physical cleaning. Advanced physical cleaning can be effective also for the removal of inorganic S. Environmental risks from the emission of other elements with enrichment or relatively low cleanabilities could be small because these elements generally have very low concentrations in Illinois coals or are largely retained in solid residues during coal combustion. ?? 1998 OPA (Overseas Publishers Association) N.V. Published by license under the Gordon and Breach Science Publishers imprint.

  9. A Combined Raman Spectroscopic and Thermogravimetric Analysis Study on Oxidation of Coal with Different Ranks

    PubMed Central

    Zhang, Weiqing; Jiang, Shuguang; Hardacre, Christopher; Goodrich, Peter; Wang, Kai; Shao, Hao; Wu, Zhengyan

    2015-01-01

    Raman spectroscopy and nonisothermal thermogravimetric analysis (TGA) measurements have been reported for different rank coals (lignite, bituminous coal, and anthracite) and the relationship between the measurements was examined. It was found that the Raman spectra parameters can be used to characterize structure changes in the different rank coals, such as the band area ratios based on the curve-fitted results. Higher ranked coal was found to have higher values of IGR/IAll and I(G + GR)/IAll but lower values of ID/I(G+GR), IDL/I(G+GR), I(S + SL)/I(G+GR), and I(GL+GL')/I(G+GR). The oxidation properties of the coal samples were characterized by the reactivity indexes Tig, T20%, and Tmax from TGA data which were found to correlate well with the band area ratios of IGR/IAll, I(G + GR)/IAll, and I(S + SL)/I(G+GR). Based on these correlations, the Raman band area ratios were found to correlate with the oxidation activity of coal providing additional structural information which can be used to understand the changes in the TGA measurements. PMID:26682084

  10. Molecular accessibility in oxidized and dried coals. Quarterly report, [January--March 1994

    SciTech Connect

    Kispert, L.D.

    1994-03-01

    The objective of this research project is to determine the molecular and structural changes that occur in swelled coal as a result of oxidation and moisture loss both in the presence and absence of light using our newly developed EPR spin probe method. Looking at the over-all picture of the because of the increased cross-linking and lack of decrease in retention would be observed because of the increased cross-linking and lack of structural accessibility of the spin probes. This decrease would be observed in coals swelled in both toluene and pyridine since neither solvent is known to disrupt covalent cross-linking in coal. As the concentration of free radicals in the coal is decreased, this process would become less significant, and the production of hydroperoxides would become more important. As the oxidation process continue, production of hydroxides would cause both polar spin probes to be more strongly retained. As the hydroxyls were oxidized further to ketones, the retention of spin probe VI would become stronger than spin probe VII. However, as the ketones and hydroxyls are further oxidized to carboxylic groups, this trend would be reversed and spin probe VII. would be retained more strongly than spin probe VI. Of course, since the reaction products can form cross-links with other sections of the coal, this process would much more convoluted. A more complete picture of this process and its application to each individual spin probe is currently being prepared. It is apparent that the EPR spin probe method is very sensitive to the oxidation process in coal.

  11. MECHANISMS OF NITROUS OXIDE FORMATION IN COAL FLAMES

    EPA Science Inventory

    The paper gives results of a study, using both detailed kinetic modeling and plug-flow simulator experiments, to investigate an unknown mechanism by which N2O is formed in coal flames. This mechanism has considerable importance in determining the influence of common and advanced ...

  12. The use of coal in a solid phase reduction of iron oxide

    NASA Astrophysics Data System (ADS)

    Nokhrina, O. I.; Rozhihina, I. D.; Hodosov, I. E.

    2015-09-01

    The results of the research process of producing metalized products by solid-phase reduction of iron using solid carbonaceous reducing agents. Thermodynamic modeling was carried out on the model of the unit the Fe-C-O and system with iron ore and coal. As a result of modeling the thermodynamic boundary reducing, oxidizing, and transition areas and the value of the ratio of carbon and oxygen in the system. Simulation of real systems carried out with the gas phase obtained in the pyrolys of coal. The simulation results allow to determine the optimal cost of coal required for complete reduction of iron ore from a given composition. The kinetics of the processes of solid-phase reduction of iron using coal of various technological brands.

  13. Predicting extents of mercury oxidation in coal-derived flue gases.

    PubMed

    Niksa, Stephen; Fujiwara, Naoki

    2005-07-01

    The proposed mercury (Hg) oxidation mechanism consists of a 168-step gas phase mechanism that accounts for interaction among all important flue gas species and a heterogeneous oxidation mechanism on unburned carbon (UBC) particles, similar to established chemistry for dioxin production under comparable conditions. The mechanism was incorporated into a gas cleaning system simulator to predict the proportions of elemental and oxidized Hg species in the flue gases, given relevant coal properties (C/H/O/N/S/Cl/Hg), flue gas composition (O2, H2O, HCl), emissions (NO(X), SO(X), CO), the recovery of fly ash, fly ash loss-on-ignition (LOI), and a thermal history. Predictions are validated without parameter adjustments against datasets from lab-scale and from pilot-scale coal furnaces at 1 and 29 MWt. Collectively, the evaluations cover 16 coals representing ranks from sub-bituminous through high-volatile bituminous, including cases with Cl2 and CaCl2 injection. The predictions are, therefore, validated over virtually the entire domain of Cl-species concentrations and UBC levels of commercial interest. Additional predictions identify the most important operating conditions in the furnace and gas cleaning system, including stoichiometric ratio, NO(X), LOI, and residence time, as well as the most important coal properties, including coal-Cl.

  14. Experimental and modeling study of the effect of CH(4) and pulverized coal on selective non-catalytic reduction process.

    PubMed

    Zhang, Yanwen; Cai, Ningsheng; Yang, Jingbiao; Xu, Bo

    2008-10-01

    The reduction of nitric oxide using ammonia combined with methane and pulverized coal additives has been studied in a drop tube furnace reactor. Simulated flue gas with 1000 ppm NO(x) and 3.4% excess oxygen was generated by cylinder gas. Experiments were performed in the temperature range of 700-1200 degrees C to investigate the effects of additives on the DeNO(x) performance. Subsequently, a kinetic mechanism was modified and validated based on experimental results, and a computational kinetic modeling with CHEMKIN was conducted to analyze the secondary pollutants. For both methane and pulverized coal additives, the temperature window is shifted towards lower temperatures. The appropriate reaction temperature is shifted to about 900 and 800 degrees C, respectively with 1000 ppm methane and 0.051 g min(-1) pulverized lignite coal. The addition of methane and pulverized coal widens the temperature window towards lower temperature suggesting a low temperature application of the process. Furthermore, selective non-catalytic reduction (SNCR) reaction rate is accelerated evidently with additives and the residence time to complete the reaction is shortened distinctly. NO(x) reduction efficiency with 80% is achieved in about 0.3s without additive at 1000 degrees C. However, it is achieved in only about 0.2s with 100 ppm methane as additive, and only 0.07 and 0.05s are needed respectively for the cases of 500 and 1000 ppm methane. The modified kinetic modeling agrees well with the experimental results and reveals additional information about the process. Investigation on the byproducts where NO(2) and N(2)O were analyzed by modeling and the others were investigated by experimental means indicates that emissions would not increase with methane and pulverized coal additions in SNCR process and the efficacious temperature range of SNCR reaction is widened approximately with 100 degrees C.

  15. Protocols for the selective cleavage of carbon-sulfur bonds in coal

    SciTech Connect

    Bausch, M.

    1991-01-01

    Removal of the organic sulfur in coal constitutes one of the major challenges facing fossil fuel scientists today. A cost--effective of desulfurizing Illinois coal is non-existent at the present time. Research in our group aims to develop a simple protocol for sulfur removal by gaining understanding of how various additives can enhance the rates of C-S bond cleavage in Illinois coal and coal model compounds, relative to fragmentation of the coal macromolecule via C-C, C-O, and C-N bond cleavage. During this funding period, we plan to carry out examinations of: (a) the effects of various reaction conditions on radical-initiated and Lewis acid-catalyzed C-S bond cleavages; (b) the effects of caustic impregnation and subsequent alcoholic reflux on C-S bond cleavage strategies; (c) the reactions of coal model compounds with electron-deficient substrates; (d) examinations of photooxidative C-S bond cleavage reactions; (e) the effects of moderate (300--400{degrees}C) temperatures and pressures as well as ultrasonic radiation on (a) - (c). Also planned are differential scanning calorimetric (DSC) examinations of selected C-S bond cleavage protocols, including those on Illinois coals that possess varying amounts of organic and inorganic sulfur.

  16. The effect of selective absorption on coal conversion. [2-t-butyltetralin

    SciTech Connect

    Larsen, J.W.; Lazarov, L.

    1991-07-01

    Scope of work: (1) Importance of hydrogen donors in the coal, prepare highly pure 2-t-butyltetralin. Study the conversion of Argonne coals in tetralin and 2-t-butyltetralin and compare the following: conversion to soluble products, product molecular weight distributions, and product structure. Hydrogen donated by both solvents will be measured by gas chromatography and the same technique will be used to establish the amount of dealkylation of 2-t-butyltetralin. Reactions will be run at several temperatures for varying times. (2) Selective recycle solvent absorption. Argonne coals will be exposed to recycle solvents at several elevated temperatures and the non-absorbed portion of the solvent will be separated by filtration. The composition of the whole oil and non-absorbed portion will be analyzed spectroscopically and chromatographically and compared to determine the composition of the recycle oil dissolved in the coal. 6 figs., 1 tab.

  17. Evaluation of BOC'S Lotox Process for the Oxidation of Elemental Mercury in Flue Gas from a Coal-Fired Boiler

    SciTech Connect

    Khalid Omar

    2008-04-30

    Linde's Low Temperature Oxidation (LoTOx{trademark}) process has been demonstrated successfully to remove more than 90% of the NOx emitted from coal-fired boilers. Preliminary findings have shown that the LoTOx{trademark} process can be as effective for mercury emissions control as well. In the LoTOx{trademark} system, ozone is injected into a reaction duct, where NO and NO{sub 2} in the flue gas are selectively oxidized at relatively low temperatures and converted to higher nitrogen oxides, which are highly water soluble. Elemental mercury in the flue gas also reacts with ozone to form oxidized mercury, which unlike elemental mercury is water-soluble. Nitrogen oxides and oxidized mercury in the reaction duct and residual ozone, if any, are effectively removed in a wet scrubber. Thus, LoTOx{trademark} appears to be a viable technology for multi-pollutant emission control. To prove the feasibility of mercury oxidation with ozone in support of marketing LoTOx{trademark} for multi-pollutant emission control, Linde has performed a series of bench-scale tests with simulated flue gas streams. However, in order to enable Linde to evaluate the performance of the process with a flue gas stream that is more representative of a coal-fired boiler; one of Linde's bench-scale LoTOx{trademark} units was installed at WRI's combustion test facility (CTF), where a slipstream of flue gas from the CTF was treated. The degree of mercury and NOx oxidation taking place in the LoTOx{trademark} unit was quantified as a function of ozone injection rates, reactor temperatures, residence time, and ranks of coals. The overall conclusions from these tests are: (1) over 80% reduction in elemental mercury and over 90% reduction of NOx can be achieved with an O{sub 3}/NO{sub X} molar ratio of less than two, (2) in most of the cases, a lower reactor temperature is preferred over a higher temperature due to ozone dissociation, however, the combination of both low residence time and high temperature

  18. Effect of carbon entrapped in Co-Al double oxides on structural restacking and electrochemical performances

    NASA Astrophysics Data System (ADS)

    Su, Ling-Hao; Zhang, Xiao-Gang

    Co-Al layered double hydroxides (LDH) were synthesized from nitrates and sodium benzoate by direct coprecipitation, and heated at 600 °C for 3 h in argon gas flow to obtain Co-Al double oxides. The effect of carbon, created during the pyrolysis of benzoate and inserted in resulting double oxides, on structural reconstruction was investigated by X-ray diffraction, scanning electron microscope, Raman spectroscopy, and infrared spectroscopy techniques. It is horizontal arrangement rather than vertical dilayer orientation in the interlayer spacing that was adopted by benzoate. An abnormal phenomenon was found that when immersed in aqueous 6 M KOH solution in air, the double oxides restacked to Co-Al layered double hydroxides with more regular crystal than before. The reason is believed that carbon was confined in the matrix of resulting double oxides, which prevented further collapse of the layered structure. Cyclic voltammetries (CV) and constant current charge/discharge measurements reveal that the restacked Co-Al layered double hydroxide has good long-life capacitive performance with a capacitance up to 145 F g -1 even at a large current of 2 A g -1. In addition, two clear slopes in chronoampermetric test demonstrated two different diffusion coefficients, explaining the slope of about 118.4 mV in the plot of formal potential E f versus pOH.

  19. NOVEL ECONOMICAL HG(0) OXIDATION REAGENT FOR MERCURY EMISSIONS CONTROL FROM COAL-FIRED BOILERS

    EPA Science Inventory

    The authors have developed a novel economical additive for elemental mercury (Hg0) removal from coal-fired boilers. The oxidation reagent was rigorously tested in a lab-scale fixed-bed column with the Norit America's FGD activated carbon (DOE's benchmark sorbent) in a typical PRB...

  20. Formation and destruction of nitrogen oxides in coal combustion. [Reburning

    SciTech Connect

    Chen, W.Y.; Lester, T.W.; Babcock, L.

    1988-01-01

    The study of stoichiometric constraints under equilibrium conditions provides us with the following information related to reburning as a NO reduction technology: (1) The stoichiometry of air to fuel is the most important stoichiometry of air to fuel is the most important stoichiometric variable for reburning; (2) based on equivalent energy production, the comparative reduction efficiencies of the reburning fuels follow the trend: methane > ethane, ammonia > butane > aromatics, coal > CO; (3) the nitrogen in burning coals causes increases in equilibrium NO; (4) equilibrium TFN is not very sensitive in inlet NO concentration; (5) the heat carried by the flue gas in reburning could push the NO reduction toward equilibrium. If so, reburning has a strong correlation with air staging with air preheat. Further experimental verification is required.

  1. Application of infiltrated LSCM-GDC oxide anode in direct carbon/coal fuel cells.

    PubMed

    Yue, Xiangling; Arenillas, Ana; Irvine, John T S

    2016-08-15

    Hybrid direct carbon/coal fuel cells (HDCFCs) utilise an anode based upon a molten carbonate salt with an oxide conducting solid electrolyte for direct carbon/coal conversion. They can be fuelled by a wide range of carbon sources, and offer higher potential chemical to electrical energy conversion efficiency and have the potential to decrease CO2 emissions compared to coal-fired power plants. In this study, the application of (La, Sr)(Cr, Mn)O3 (LSCM) and (Gd, Ce)O2 (GDC) oxide anodes was explored in a HDCFC system running with two different carbon fuels, an organic xerogel and a raw bituminous coal. The electrochemical performance of the HDCFC based on a 1-2 mm thick 8 mol% yttria stabilised zirconia (YSZ) electrolyte and the GDC-LSCM anode fabricated by wet impregnation procedures was characterized and discussed. The infiltrated oxide anode showed a significantly higher performance than the conventional Ni-YSZ anode, without suffering from impurity formation under HDCFC operation conditions. Total polarisation resistance (Rp) reached 0.8-0.9 Ω cm(2) from DCFC with an oxide anode on xerogel and bituminous coal at 750 °C, with open circuit voltage (OCV) values in the range 1.1-1.2 V on both carbon forms. These indicated the potential application of LSCM-GDC oxide anode in HDCFCs. The chemical compatibility of LSCM/GDC with carbon/carbonate investigation revealed the emergence of an A2BO4 type oxide in place of an ABO3 perovskite structure in the LSCM in a reducing environment, due to Li attack as a result of intimate contact between the LSCM and Li2CO3, with GDC being stable under identical conditions. Such reaction between LSCM and Li2CO3 was not observed on a LSCM-YSZ pellet treated with Li-K carbonate in 5% H2/Ar at 700 °C, nor on a GDC-LSCM anode after HDCFC operation. The HDCFC durability tests of GDC-LSCM oxide on a xerogel and on raw bituminous coal were performed under potentiostatic operation at 0.7 V at 750 °C. The degradation mechanisms were

  2. Application of infiltrated LSCM-GDC oxide anode in direct carbon/coal fuel cells.

    PubMed

    Yue, Xiangling; Arenillas, Ana; Irvine, John T S

    2016-08-15

    Hybrid direct carbon/coal fuel cells (HDCFCs) utilise an anode based upon a molten carbonate salt with an oxide conducting solid electrolyte for direct carbon/coal conversion. They can be fuelled by a wide range of carbon sources, and offer higher potential chemical to electrical energy conversion efficiency and have the potential to decrease CO2 emissions compared to coal-fired power plants. In this study, the application of (La, Sr)(Cr, Mn)O3 (LSCM) and (Gd, Ce)O2 (GDC) oxide anodes was explored in a HDCFC system running with two different carbon fuels, an organic xerogel and a raw bituminous coal. The electrochemical performance of the HDCFC based on a 1-2 mm thick 8 mol% yttria stabilised zirconia (YSZ) electrolyte and the GDC-LSCM anode fabricated by wet impregnation procedures was characterized and discussed. The infiltrated oxide anode showed a significantly higher performance than the conventional Ni-YSZ anode, without suffering from impurity formation under HDCFC operation conditions. Total polarisation resistance (Rp) reached 0.8-0.9 Ω cm(2) from DCFC with an oxide anode on xerogel and bituminous coal at 750 °C, with open circuit voltage (OCV) values in the range 1.1-1.2 V on both carbon forms. These indicated the potential application of LSCM-GDC oxide anode in HDCFCs. The chemical compatibility of LSCM/GDC with carbon/carbonate investigation revealed the emergence of an A2BO4 type oxide in place of an ABO3 perovskite structure in the LSCM in a reducing environment, due to Li attack as a result of intimate contact between the LSCM and Li2CO3, with GDC being stable under identical conditions. Such reaction between LSCM and Li2CO3 was not observed on a LSCM-YSZ pellet treated with Li-K carbonate in 5% H2/Ar at 700 °C, nor on a GDC-LSCM anode after HDCFC operation. The HDCFC durability tests of GDC-LSCM oxide on a xerogel and on raw bituminous coal were performed under potentiostatic operation at 0.7 V at 750 °C. The degradation mechanisms were

  3. Catalysts for the selective oxidation of hydrogen sulfide to sulfur

    DOEpatents

    Srinivas, Girish; Bai, Chuansheng

    2000-08-08

    This invention provides catalysts for the oxidation of hydrogen sulfide. In particular, the invention provides catalysts for the partial oxidation of hydrogen sulfide to elemental sulfur and water. The catalytically active component of the catalyst comprises a mixture of metal oxides containing titanium oxide and one or more metal oxides which can be selected from the group of metal oxides or mixtures of metal oxides of transition metals or lanthanide metals. Preferred metal oxides for combination with TiO.sub.2 in the catalysts of this invention include oxides of V, Cr, Mn, Fe, Co, Ni, Cu, Nb, Mo, Tc, Ru, Rh, Hf, Ta, W, Au, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu. Catalysts which comprise a homogeneous mixture of titanium oxide and niobium (Nb) oxide are also provided. A preferred method for preparing the precursor homogenous mixture of metal hydroxides is by coprecipitation of titanium hydroxide with one or more other selected metal hydroxides. Catalysts of this invention have improved activity and/or selectivity for elemental sulfur production. Further improvements of activity and/or selectivity can be obtained by introducing relatively low amounts (up to about 5 mol %)of a promoter metal oxide (preferably of metals other than titanium and that of the selected second metal oxide) into the homogeneous metal/titanium oxide catalysts of this invention.

  4. Process for selected gas oxide removal by radiofrequency catalysts

    DOEpatents

    Cha, Chang Y.

    1993-01-01

    This process to remove gas oxides from flue gas utilizes adsorption on a char bed subsequently followed by radiofrequency catalysis enhancing such removal through selected reactions. Common gas oxides include SO.sub.2 and NO.sub.x.

  5. Graphene Oxide Selectively Enhances Thermostability of Trypsin.

    PubMed

    Yao, Kai; Tan, Pengli; Luo, Yinchan; Feng, Liangzhu; Xu, Ligeng; Liu, Zhuang; Li, Youyong; Peng, Rui

    2015-06-10

    In the past few years, graphene and its derivative, graphene oxide (GO), have been extensively studied for their applications in biotechnology. In our previous work, we reported certain PEGylated GOs (GO-PEGs) can selectively promote trypsin activity and enhance its thermostability. To further explore this, here we synthesized a series of GO-PEGs with varying PEGylation degrees. Enzymatic activity assay shows that both GO and GO-PEGs can protect trypsin, but not chymotrypsin, from thermal denaturation at high temperature. Surprisingly, the lower the PEGylation degree, the better the protection, and GO as well as the GO-PEG with the lowest PEGylation degree show the highest protection efficiency (∼70% retained activity at 70 °C). Fluorescence spectroscopy analysis shows that GO/GO-PEGs have strong interactions with trypsin. Molecular Dynamics (MD) simulation results reveal that trypsin is adsorbed onto the surface of GO through its cationic residues and hydrophilic residues. Different from chymotrypsin adsorbed on GO, the active site of trypsin is covered by GO. MD simulation at high temperature shows that, through such interaction with GO, trypsin's active site is therefore stabilized and protected by GO. Our work not only illustrates the promising potential of GO/GO-PEGs as efficient, selective modulators for trypsin, but also provides the interaction mechanism of GO with specific proteins at the nano-bio interface. PMID:25985836

  6. Protocols for the selective cleavage of carbon-sulfur bonds in coal. Final technical report, September 1, 1991--August 31, 1992

    SciTech Connect

    Bausch, M.

    1992-12-31

    Summarized in the final technical report for our project ``Protocols for the Selective Cleavage of Carbon-Sulfur Bonds in Coal`` are results of research pertaining to chemical reactions that aim to selectively cleave C-S bonds in model compounds as well as Illinois coal. Removal of the organic sulfur in coal constitutes one of the major challenges facing fossil fuel scientists today. A cost-effective means of desulfurizing Illinois coal is, at present, non-existent. Research in our group aims to develop a simple protocol for sulfur removal by gaining understanding of how various additives and reaction conditions, including solvents, bases, added reagents, catalysts, oxidizing agents, electron acceptors, temperature, pressure, and light energy, can enhance the rates of C-S bond cleavage in Illinois coal and coal model compounds. These experiments have been at the focus of our research effort for the past twelve months. Previous quarterly reports described research results in which simple aromatic and aliphatic sulfides were allowed to react with (a) Lewis Acids such as zinc chloride and tin chloride; (b) electron accepting substrates such as 9-fluorenone and benzoquinone; (c) strong bases such as NaOH and KOH; (d) radical initiators such as AIBN; (e) neat solvents at reflux temperatures and higher temperatures; (f) molecular oxygen in the presence of dyes or sensitizers such as anthracene. In this final report, we report on additional experiments involving the photooxidation of organic sulfides, as well as some experiments aimed at evaluating and comparing the reactivities of simple organic sulfones with their sulfidyl analogues. Also contained in this final report is a brief summary of the research described in the previous three quarterly reports for ``Protocols for the Selective Cleavage of Carbon-Sulfur Bonds in Coal.``

  7. Protocols for the selective cleavage of carbon-sulfur bonds in coal. Technical report, December 1, 1991--February 29, 1992

    SciTech Connect

    Bausch, M.

    1992-08-01

    Planned in this project ``Protocols for the Selective Cleavage of Carbon-Sulfur Bonds in Coal`` are reactions in which organic free radicals and/or organic anions are allowed to react with physically cleaned Illinois coal and sulfur-containing coal model compounds. This quarterly report contains the results of photooxidation of coal model compounds, namely, benzyl phenyl sulfide, phenylsulfide, dibenzothiophene, benzothiophene and thiophene, in the presence of 9,10-dicyanoanthracene or anthracene. Quantitative product analysis for the matrix of reactions whereby the coal model compounds are subjected to various solvents and temperature changes is presented in this quarterly report. Further quantitative analyses of the products are being undertaken.

  8. Studies of the effect of selected nondonor solvents on coal liquefaction yields

    SciTech Connect

    Jolley, R. L.; Rodgers, B. R.; Benjamin, B. M.; Poutsma, M. L.; Douglas, E. C.; McWhirter, D. A.

    1983-09-01

    The objective of this research program was to evaluate the effectiveness of selected nondonor solvents (i.e., solvents that are not generally considered to have hydrogen available for hydrogenolysis reactions) for the solubilization of coals. Principal criteria for selection of candidate solvents were that the compound should be representative of a major chemical class, should be present in reasonable concentration in coal liquid products, and should have the potential to participate in hydrogen redistribution reactions. Naphthalene, phenanthrene, pyrene, carbazole, phenanthridine, quinoline, 1-naphthol, and diphenyl ether were evaluated to determine their effect on coal liquefaction yields and were compared with phenol and two high-quality process solvents, Wilsonville SRC-I recycle solvent and Lummus ITSL heavy oil solvent. The high conversion efficacy of 1-naphthol may be attributed to its condensation to binaphthol and the consequent availability of hydrogen. The effectiveness of both the nitrogen heterocycles and the polycyclic aromatic hydrocarbon (PAH) compounds may be due to their polycyclic aromatic nature (i.e., possible hydrogen shuttling or transfer agents) and their physical solvent properties. The relative effectiveness for coal conversion of the Lummus ITSL heavy oil solvent as compared with the Wilsonville SRC-I process solvent may be attributed to the much higher concentration of 3-, 4-, and 5-ring PAH and hydroaromatic constituents in Lummus solvent. The chemistry of coal liquefaction and the development of recycle, hydrogen donor, and nondonor solvents are reviewed. The experimental methodology for tubing-bomb tests is outlined, and experimental problem areas are discussed.

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

    USGS Publications Warehouse

    Belkin, Harvey E.; Tewalt, Susan J.

    2007-01-01

    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.

  10. Selective-oxidation catalyst improves Claus process

    SciTech Connect

    Lagas, J.A.; Borsboom, J. ); Berben, P.H. )

    1988-10-10

    Increased SO/sub 2/ emissions. On a worldwide scale, the exploitation and processing of crude oil and natural gas have increased significantly during the past 30 years. This expansion has caused severe pollution problems, especially from sulfur dioxide emissions to the atmosphere. A new development for the well-known Claus process improves production of elemental sulfur from H/sub 2/S. The ''SuperClaus'' process involves a modification of the process-control system and the use of a newly developed selective-oxidation catalyst in the third reactor with the objective of achieving a 99% or 99.5% overall sulfur recovery (two versions) without further tail-gas cleanup. The catalyst for the new process was developed and tested on laboratory bench scale for more than 3 years. Based on the results, it was decided to test the process directly in a commercial unit. A three-stage, 100-t/d Claus plant in a natural-gas plant in the Federal Republic of Germany has been retrofitted to SuperClause. Since Jan. 21, the process has been successfully operated.

  11. Selective batch crushing in the coal-preparation shop at OAO NTMK

    SciTech Connect

    N.A. Berkutov; Yu.V. Stepanov; P.V. Shtark; L.A. Makhortova; N.K. Popova; D.A. Koshkarov; N.V. Tsarev

    2007-05-15

    In September 2004, after reconstruction at OAO Nizhnetagil'skii Metallurgicheskii Kombinat (NTMK), blast furnace 6 went into operation for the production of vanadium from hot metal. At the startup of furnace 6, besides optimising its composition; it was decided to restore selective crushing of the coal batch using pneumatic and mechanical separation in the third unit of the coal preparation shop. Additional increase in the mechanical strength of coke by 1.5-2.0% was predicted with a 0.5-1.0% decrease in wear.

  12. A Sensor System Based on Semi-Conductor Metal Oxide Technology for In Situ Detection of Coal Fired Combustion Gases

    SciTech Connect

    Brent Marquis

    2007-05-31

    Sensor Research and Development Corporation (SRD) proposed a two-phase program to develop a robust, autonomous prototype analyzer for in situ, real-time detection, identification, and measurement of coal-fired combustion gases and perform field-testing at an approved power generation facility. SRD developed and selected sensor materials showing selective responses to carbon monoxide, carbon dioxide, nitric oxide, nitrogen dioxide, ammonia, sulfur dioxide and hydrogen chloride. Sensor support electronics were also developed to enable prototype to function in elevated temperatures without any issues. Field-testing at DOE approved facility showed the ability of the prototype to detect and estimate the concentration of combustion by-products accurately with relatively low false-alarm rates at very fast sampling intervals.

  13. Effect of Coal Contaminants on Solid Oxide Fuel System Performance and Service Life

    SciTech Connect

    Gopala Krishnan; P. Jayaweera; J. Bao; J. Perez; K. H. Lau; M. Hornbostel; A. Sanjurjo; J. R. Albritton; R. P. Gupta

    2008-09-30

    The U.S. Department of Energy's SECA program envisions the development of high-efficiency, low-emission, CO{sub 2} sequestration-ready, and fuel-flexible technology to produce electricity from fossil fuels. One such technology is the integrated gasification-solid oxide fuel cell (SOFC) that produces electricity from the gas stream of a coal gasifier. SOFCs have high fuel-to-electricity conversion efficiency, environmental compatibility (low NO{sub x} production), and modularity. Naturally occurring coal has many impurities and some of these impurities end in the fuel gas stream either as a vapor or in the form of fine particulate matter. Establishing the tolerance limits of SOFCs for contaminants in the coal-derived gas will allow proper design of the fuel feed system that will not catastrophically damage the SOFC or allow long-term cumulative degradation. The anodes of Ni-cermet-based SOFCs are vulnerable to degradation in the presence of contaminants that are expected to be present in a coal-derived fuel gas stream. Whereas the effects of some contaminants such as H{sub 2}S, NH{sub 3} and HCl have been studied, the effects of other contaminants such as As, P, and Hg have not been ascertained. The primary objective of this study was to determine the sensitivity of the performance of solid oxide fuel cells to trace level contaminants present in a coal-derived gas stream in the temperature range 700 to 900 C. The results were used to assess catastrophic damage risk and long-term cumulative effects of the trace contaminants on the lifetime expectancy of SOFC systems fed with coal-derived gas streams.

  14. Selected coal-related ground-water data, Wasatch Plateau-Book Cliffs area, Utah

    USGS Publications Warehouse

    Sumsion, C.T.

    1979-01-01

    The Wasatch Plateau-Book Cliffs area in east-central Utah consists of about 8,000 square miles within the upper Colorado River drainage system. Coal production in the area is expected to increase from 8 million tons to as much as 30 million tons annually within the next 10 years. Most sources of water supply will be subjected to possible contamination and increased demands by coal-related municipal and industrial growth in the area. The report presents a compilation of coal-related ground-water data from many unpublished sources for the use of local and regional water planners and users. The report includes generalized stratigraphic sections and hydrologic characteristics of rocks in the Wasatch Plateau-Book Cliffs area , records of selected test holes and water wells, logs of selected test holes and water wells, water levels in selected wells, records of selected springs, records of ground-water discharge from selected mines, and chemical analyses of water from selected test holes, water wells, springs, and mines. (Kosco-USGS)

  15. Significance of RuO2 modified SCR catalyst for elemental mercury oxidation in coal-fired flue gas.

    PubMed

    Yan, Naiqiang; Chen, Wanmiao; Chen, Jie; Qu, Zan; Guo, Yongfu; Yang, Shijian; Jia, Jinping

    2011-07-01

    Catalytic conversion of elemental mercury (Hg(0)) to its oxidized form has been considered as an effective way to enhance mercury removal from coal-fired power plants. In order to make good use of the existing selective catalytic reduction of NO(x) (SCR) catalysts as a cobenefit of Hg(0) conversion at lower level HCl in flue gas, various catalysts supported on titanium dioxide (TiO(2)) and commercial SCR catalysts were investigated at various cases. Among the tested catalysts, ruthenium oxides (RuO(2)) not only showed rather high catalytic activity on Hg(0) oxidation by itself, but also appeared to be well cooperative with the commercial SCR catalyst for Hg(0) conversion. In addition, the modified SCR catalyst with RuO(2) displayed an excellent tolerance to SO(2) and ammonia without any distinct negative effects on NO(x) reduction and SO(2) conversion. The demanded HCl concentration for Hg(0) oxidation can be reduced dramatically, and Hg(0) oxidation efficiency over RuO(2) doped SCR catalyst was over 90% even at about 5 ppm HCl in the simulated gases. Ru modified SCR catalyst shows a promising prospect for the cobenefit of mercury emission control.

  16. COAL CLEANING VIA LIQUID-FLUIDIZED CLASSIFICAITON (LFBC) WITH SELECTIVE SOLVENT SWELLING

    SciTech Connect

    J. M. Calo

    2000-12-01

    The concept of coal beneficiation due to particle segregation in water-fluidized beds, and its improvement via selective solvent-swelling of organic material-rich coal particles, was investigated in this study. Particle size distributions and their behavior were determined using image analysis techniques, and beneficiation effects were explored via measurements of the ash content of segregated particle samples collected from different height locations in a 5 cm diameter liquid-fluidized bed column (LFBC). Both acetone and phenol were found to be effective swelling agents for both Kentucky No.9 and Illinois No.6 coals, considerably increasing mean particle diameters, and shifting particle size distributions to larger sizes. Acetone was a somewhat more effective swelling solvent than phenol. The use of phenol was investigated, however, to demonstrate that low cost, waste solvents can be effective as well. For unswollen coal particles, the trend of increasing particle size from top to bottom in the LFBC was observed in all cases. Since the organic matter in the coal tends to concentrate in the smaller particles, the larger particles are typically denser. Consequently, the LFBC naturally tends to separate coal particles according to mineral matter content, both due to density and size. The data for small (40-100 {micro}m), solvent-swollen particles clearly showed improved beneficiation with respect to segregation in the water-fluidized bed than was achieved with the corresponding unswollen particles. This size range is quite similar to that used in pulverized coal combustion. The original process concept was amply demonstrated in this project. Additional work remains to be done, however, in order to develop this concept into a full-scale process.

  17. Conducting oxide formation and mechanical endurance of potential solid-oxide fuel cell interconnects in coal syngas environment

    NASA Astrophysics Data System (ADS)

    Liu, Kejia; Luo, Junhang; Johnson, Chris; Liu, Xingbo; Yang, J.; Mao, Scott X.

    The oxidation properties of potential SOFCs materials Crofer 22 APU, Ebrite and Haynes 230 exposed in coal syngas at 800 °C for 100 h were studied. The phases and surface morphology of the oxide scales were characterized by X-ray diffraction, scanning electron microscopy and energy-dispersive X-ray analysis (EDX). The mechanical endurance and electrical resistance of the conducting oxides were characterized by indentation and electrical impedance, respectively. It was found that the syngas exposure caused the alloys to form porous oxide scales, which increased the electrical resistant and decreased the mechanical stability. As for short-term exposure in syngas, neither carbide nor metal dusting was found in the scales of all samples.

  18. Durable zinc oxide-containing sorbents for coal gas desulfurization

    SciTech Connect

    Siriwardane, R.V.

    1994-12-31

    Durable zinc-oxide containing sorbent pellets for removing hydrogen sulfide from a gas stream at an elevated temperature are made up to contain titania as a diluent, high-surface-area silica gel as a matrix material, and a binder. These materials are mixed, moistened, and formed into pellets, which are then dried and calcined. The resulting pellets undergo repeated cycles of sulfidation and regeneration without loss of reactivity and without mechanical degradation. Regeneration of the pellets is carried out by contacting the bed with an oxidizing gas mixture.

  19. Durable zinc oxide-containing sorbents for coal gas desulfurization

    DOEpatents

    Siriwardane, Ranjani V.

    1996-01-01

    Durable zinc-oxide containing sorbent pellets for removing hydrogen sulfide from a gas stream at an elevated temperature are made up to contain titania as a diluent, high-surface-area silica gel, and a binder. These materials are mixed, moistened, and formed into pellets, which are then dried and calcined. The resulting pellets undergo repeated cycles of sulfidation and regeneration without loss of reactivity and without mechanical degradation. Regeneration of the pellets is carried out by contacting the bed with an oxidizing gas mixture.

  20. Surface properties of photo-oxidized bituminous coals. Technical progress report, October--December 1995

    SciTech Connect

    Mitchell, G.; Polat, H.; Davis, A.; Chander, S.

    1996-02-01

    During this report period, polished blocks of coal containing 3--4 mm wide vitrain bands were prepared for contact angle measurements of fresh and photo-oxidized surfaces using the advancing-drop technique. Contact angles were measured on two of the coals collected for this study, (the Ohio No. 4a (DECS-33) and Lower Kittanning (PSOC-1562) seams) and the results added to those presented in the last quarterly report. Although the new data give additional variation to the sample set, they are consistent with the original observations, i.e., that contact angle is influenced by irradiation time and coal rank. Using the maximum change in contact angle measured between fresh and photo-oxidized surfaces, a linear decrease is observed with increasing rank resulting from 5 and 10 minutes of irradiation. The magnitude of the decrease in contact angle diminishes with increasing rank. Also during this period, an ultraviolet spotlight was evaluated as a means of irradiating powdered vitrain. This 100 watt, long wavelength (366 nm) ultraviolet lamp is to be used in place of the optical microscope system to establish the influence of surface photo-oxidation on the flotation characteristics of vitrain concentrates. A series of experiments was designed to determine the magnitude of change in the luminescence intensity (at 600 nm measured in the optical microscope) with exposure to the ultraviolet light with time for vitrinite from different rank coals. The authors have established that there is a significant decrease in luminescence intensity with time of exposure which diminishes slightly as rank increases. The ultraviolet light appears to provide a level of photo-oxidation that is a factor of 10 lower than that obtained with their optical microscope system.

  1. The mechanism of coal gas desulfurization by iron oxide sorbents.

    PubMed

    Lin, Yi-Hsing; Chen, Yen-Chiao; Chu, Hsin

    2015-02-01

    This study aims to understand the roles of hydrogen and carbon monoxide during the desulfurization process in a coal gasification system that H2S of the syngas was removed by Fe2O3/SiO2 sorbents. The Fe2O3/SiO2 sorbents were prepared by incipient wetness impregnation. Through the breakthrough experiments and Fourier transform infrared spectroscopy analyses, the overall desulfurization mechanism of the Fe2O3/SiO2 sorbents was proposed in this study. The results show that the major reaction route is that Fe2O3 reacts with H2S to form FeS, and the existence of CO and H2 in the simulated gas significantly affects equilibrium concentrations of H2S and COS. The formation of COS occurs when the feeding gas is blended with CO and H2S, or CO2 and H2S. The pathways in the formation of products from the desulfurization process by the reaction of Fe2O3 with H2S have been successfully established. PMID:25434261

  2. Quartz in coal dust deposited on internal surface of respirable size selective samplers.

    PubMed

    Soo, Jhy-Charm; Lee, Taekhee; Kashon, Michael; Kusti, Mohannad; Harper, Martin

    2014-01-01

    The objective of the present study is to quantify quartz mass in coal dust deposited on the internal cassette surface of respirable size-selective samplers. Coal dust was collected with four different respirable size-selective samplers (10 mm Dorr-Oliver nylon [Sensidyne, St. Petersburg, Fla.], SKC Aluminum [SKC Inc., Eighty Four, Pa.], BGI4L [BGI USA Inc., Waltham, Mass.], and GK2.69 cyclones [BGI USA Inc.]) with two different cassette types (polystyrene and static-dissipative polypropylene cassettes). The coal dust was aerosolized in a calm air chamber by using a fluidized bed aerosol generator without neutralization under the assumption that the procedure is similar to field sampling conditions. The mass of coal dust was measured gravimetrically and quartz mass was determined by Fourier transform infrared spectroscopy according to the National Institute for Occupational Safety and Health (NIOSH) Manual of Analytical Methods, Method 7603. The mass fractions of the total quartz sample on the internal cassette surface are significantly different between polystyrene and static-dissipative cassettes for all cyclones (p < 0.05). No consistent relationship between quartz mass on cassette internal surface and coal dust filter mass was observed. The BGI4L cyclone showed a higher (but not significantly) and the GK2.69 cyclone showed a significantly lower (p < 0.05) internal surface deposit quartz mass fraction for polystyrene cassettes compared to other cyclones. This study confirms previous observations that the interior surface deposits in polystyrene cassettes attached to cyclone pre-selectors can be a substantial part of the sample, and therefore need to be included in any analysis for accurate exposure assessment. On the other hand, the research presented here supports the position that the internal surface deposits in static-dissipative cassettes used with size-selective cyclones are negligible and that it is only necessary to analyze the filter catch.

  3. KINETICS OF DIRECT OXIDATION OF H2S IN COAL GAS TO ELEMENTAL SULFUR

    SciTech Connect

    K.C. Kwon

    2004-01-01

    The direct oxidation of H{sub 2}S to elemental sulfur in the presence of SO{sub 2} is ideally suited for coal gas from commercial gasifiers with a quench system to remove essentially all the trace contaminants except H{sub 2}S. This direct oxidation process has the potential to produce a super clean coal gas more economically than both conventional amine-based processes and the hot-gas desulfurization using regenerable metal oxide sorbents followed by Direct Sulfur Recovery Process. The objective of this research is to support the near- and long-term process development efforts to commercialize this direct oxidation technology. The objectives of this research are to measure kinetics of direct oxidation of H{sub 2}S to elemental sulfur in the presence of a simulated coal gas mixture containing SO{sub 2}, H{sub 2}, and moisture, using 160-{micro}m C-500-04 alumina catalyst particles and a micro bubble reactor, and to develop kinetic rate equations and model the direct oxidation process to assist in the design of large-scale plants. This heterogeneous catalytic reaction has gaseous reactants such as H{sub 2}S and SO{sub 2}. However, this heterogeneous catalytic reaction has heterogeneous products such as liquid elemental sulfur and steam. To achieve the above-mentioned objectives, experiments on conversion of hydrogen sulfide into liquid elemental sulfur were carried out for the space time range of 1-6 milliseconds at 125-155 C to evaluate effects of reaction temperature, moisture concentration, reaction pressure on conversion of hydrogen sulfide into liquid elemental sulfur. Simulated coal gas mixtures consist of 70 v% hydrogen, 2,500-7,500-ppmv hydrogen sulfide, 1,250-3,750 ppmv sulfur dioxide, and 0-15 vol% moisture, and nitrogen as remainder. Volumetric feed rates of a simulated coal gas mixture to a micro bubble reactor are 100 cm{sup 3}/min at room temperature and atmospheric pressure. The temperature of the reactor is controlled in an oven at 125-155 C. The

  4. KINETICS OF DIRECT OXIDATION OF H2S IN COAL GAS TO ELEMENTAL SULFUR

    SciTech Connect

    K.C. Kwon

    2005-01-01

    The direct oxidation of H{sub 2}S to elemental sulfur in the presence of SO{sub 2} is ideally suited for coal gas from commercial gasifiers with a quench system to remove essentially all the trace contaminants except H{sub 2}S. This direct oxidation process has the potential to produce a super clean coal gas more economically than both conventional amine-based processes and the hot-gas desulfurization using regenerable metal oxide sorbents followed by Direct Sulfur Recovery Process. The objective of this research is to support the near- and long-term process development efforts to commercialize this direct oxidation technology. The objectives of this research are to measure kinetics of direct oxidation of H{sub 2}S to elemental sulfur in the presence of a simulated coal gas mixture containing SO{sub 2}, H{sub 2}, and moisture, using 160-{micro}m C-500-04 alumina catalyst particles and a micro bubble reactor, and to develop kinetic rate equations and model the direct oxidation process to assist in the design of large-scale plants. This heterogeneous catalytic reaction has gaseous reactants such as H{sub 2}S and SO{sub 2}. However, this heterogeneous catalytic reaction has heterogeneous products such as liquid elemental sulfur and steam. To achieve the above-mentioned objectives, experiments on conversion of hydrogen sulfide into liquid elemental sulfur were carried out for the space time range of 0.059-0.87 seconds at 125-155 C to evaluate effects of reaction temperature, H{sub 2}S concentration, reaction pressure, and catalyst loading on conversion of hydrogen sulfide into liquid elemental sulfur. Simulated coal gas mixtures consist of 62-78 v% hydrogen, 3,000-7,000-ppmv hydrogen sulfide, 1,500-3,500 ppmv sulfur dioxide, and 10 vol % moisture, and nitrogen as remainder. Volumetric feed rates of a simulated coal gas mixture to a micro bubble reactor are 50 cm{sup 3}/min at room temperature and atmospheric pressure. The temperature of the reactor is controlled in an

  5. Process and analytical studies of enhanced low severity co-processing using selective coal pretreatment. Final technical report

    SciTech Connect

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

    1991-12-01

    The findings in the first phase were as follows: 1. Both reductive (non-selective) alkylation and selective oxygen alkylation brought about an increase in liquefaction reactivity for both coals. 2. Selective oxygen alkylation is more effective in enhancing the reactivity of low rank coals. In the second phase of studies, the major findings were as follows: 1. Liquefaction reactivity increases with increasing level of alkylation for both hydroliquefaction and co-processing reaction conditions. 2. the increase in reactivity found for O-alkylated Wyodak subbituminous coal is caused by chemical changes at phenolic and carboxylic functional sites. 3. O-methylation of Wyodak subbituminous coal reduced the apparent activation energy for liquefaction of this coal.

  6. Catalytic effect of metallic oxides on combustion behavior of high ash coal

    SciTech Connect

    X.G. Li; B.G. Ma; L. Xu; Z.T. Luo; K. Wang

    2007-09-15

    By means of thermogravimetric analysis, the catalytic effect of metallic oxides (CuO, Fe{sub 2}O{sub 3}, and ZnO) on the combustion behavior of high-ash coal was investigated under nonisothermal conditions. Experiments were conducted from ambient temperature to 1000{sup o}C at a heating rate of 20{sup o}C{center_dot}min{sup -1}. The ignition temperature, burnout performance, and exothermic behavior were used to evaluate the catalytic effect. Moreover, the kinetics parameters (activation energy and pre-exponential factor) were determined using the Coats-Redfern method. It is indicated that, compared with the combustion characteristics of high-ash coal, the ignition temperature of the samples with metallic oxides decreases by 8-50{sup o}C. Metallic oxides can speed up the combustion rate and burnout of the fixed carbon. The exothermic values of samples incorporating metallic oxides increase by 15-30%, which may be due to the catalytic effect of metallic oxides on fixed carbon combustion. The activation energies of the samples decrease, and there is a linear connection between the activation energies and pre-exponential factors (ln A = 0.2683 x E-12.807). 19 refs., 2 figs., 2 tabs.

  7. Modeling Selective Intergranular Oxidation of Binary Alloys

    SciTech Connect

    Xu, Zhijie; Li, Dongsheng; Schreiber, Daniel K.; Rosso, Kevin M.; Bruemmer, Stephen M.

    2015-01-07

    Intergranular attack of alloys under hydrothermal conditions is a complex problem that depends on metal and oxygen transport kinetics via solid-state and channel-like pathways to an advancing oxidation front. Experiments reveal very different rates of intergranular attack and minor element depletion distances ahead of the oxidation front for nickel-based binary alloys depending on the minor element. For example, a significant Cr depletion up to 9 µm ahead of grain boundary crack tips were documented for Ni-5Cr binary alloy, in contrast to relatively moderate Al depletion for Ni-5Al (~100s of nm). We present a mathematical kinetics model that adapts Wagner’s model for thick film growth to intergranular attack of binary alloys. The transport coefficients of elements O, Ni, Cr, and Al in bulk alloys and along grain boundaries were estimated from the literature. For planar surface oxidation, a critical concentration of the minor element can be determined from the model where the oxide of minor element becomes dominant over the major element. This generic model for simple grain boundary oxidation can predict oxidation penetration velocities and minor element depletion distances ahead of the advancing front that are comparable to experimental data. The significant distance of depletion of Cr in Ni-5Cr in contrast to the localized Al depletion in Ni-5Al can be explained by the model due to the combination of the relatively faster diffusion of Cr along the grain boundary and slower diffusion in bulk grains, relative to Al.

  8. Modeling selective intergranular oxidation of binary alloys

    NASA Astrophysics Data System (ADS)

    Xu, Zhijie; Li, Dongsheng; Schreiber, Daniel K.; Rosso, Kevin M.; Bruemmer, Stephen M.

    2015-01-01

    Intergranular attack of alloys under hydrothermal conditions is a complex problem that depends on metal and oxygen transport kinetics via solid-state and channel-like pathways to an advancing oxidation front. Experiments reveal very different rates of intergranular attack and minor element depletion distances ahead of the oxidation front for nickel-based binary alloys depending on the minor element. For example, a significant Cr depletion up to 9 μm ahead of grain boundary crack tips was documented for Ni-5Cr binary alloy, in contrast to relatively moderate Al depletion for Ni-5Al (˜100 s of nm). We present a mathematical kinetics model that adapts Wagner's model for thick film growth to intergranular attack of binary alloys. The transport coefficients of elements O, Ni, Cr, and Al in bulk alloys and along grain boundaries were estimated from the literature. For planar surface oxidation, a critical concentration of the minor element can be determined from the model where the oxide of minor element becomes dominant over the major element. This generic model for simple grain boundary oxidation can predict oxidation penetration velocities and minor element depletion distances ahead of the advancing front that are comparable to experimental data. The significant distance of depletion of Cr in Ni-5Cr in contrast to the localized Al depletion in Ni-5Al can be explained by the model due to the combination of the relatively faster diffusion of Cr along the grain boundary and slower diffusion in bulk grains, relative to Al.

  9. Summary of selected water-quality data for the Warrior coal field, Alabama

    USGS Publications Warehouse

    Mooty, W.S.

    1985-01-01

    A summary is presented of selected water quality data collected from 1976 to 1984 at 75 surface water sites and 28 test wells in the Warrior coal field in northwestern Alabama. The minimum, maximum, mean or median, standard deviation, and number of determinations are given for each site for discharge, pH, alkalinity, specific conductance, hardness, dissolved and suspended solids, sulfate, and total and dissolved iron and manganese. Twelve quadrangles are included in the report showing the location of each site. (USGS)

  10. Performance of solid oxide fuel cells operated with coal syngas provided directly from a gasification process

    NASA Astrophysics Data System (ADS)

    Hackett, Gregory A.; Gerdes, Kirk; Song, Xueyan; Chen, Yun; Shutthanandan, Vaithiyalingam; Engelhard, Mark; Zhu, Zihua; Thevuthasan, Suntharampillai; Gemmen, Randall

    2012-09-01

    Solid oxide fuel cells (SOFCs) are being developed for integrated gasification power plants that generate electricity from coal at 50+% efficiency. The interaction of trace metals in coal syngas with Ni-based SOFC anodes is being investigated through thermodynamic analyses and in laboratory experiments, but test data from direct coal syngas exposure are sparsely available. This effort evaluates the significance of performance losses associated with exposure to direct coal syngas. Specimen are operated in a unique mobile test skid that is deployed to the research gasifier at NCCC in Wilsonville, AL. The test skid interfaces with a gasifier slipstream to deliver hot syngas to a parallel array of twelve SOFCs. During the 500 h test period, all twelve cells are monitored for performance at four current densities. Degradation is attributed to syngas exposure and trace material attack on the anode structure that is accelerated at increasing current densities. Cells that are operated at 0 and 125 mA cm-2 degrade at 9.1 and 10.7% per 1000 h, respectively, while cells operated at 250 and 375 mA cm-2 degrade at 18.9 and 16.2% per 1000 h, respectively. Spectroscopic analysis of the anodes showed carbon, sulfur, and phosphorus deposits; no secondary Ni-metal phases were found.

  11. Performance of solid oxide fuel cells operaated with coal syngas provided directly from a gasification process

    SciTech Connect

    Hackett, G.; Gerdes, K.; Song, X.; Chen, Y.; Shutthanandan, V.; Englehard, M.; Zhu, Z.; Thevuthasan, S.; Gemmen, R.

    2012-01-01

    Solid oxide fuel cells (SOFCs) are being developed for integrated gasification power plants that generate electricity from coal at 50% efficiency. The interaction of trace metals in coal syngas with Ni-based SOFC anodes is being investigated through thermodynamic analyses and in laboratory experiments, but test data from direct coal syngas exposure are sparsely available. This effort evaluates the significance of performance losses associated with exposure to direct coal syngas. Specimen are operated in a unique mobile test skid that is deployed to the research gasifier at NCCC in Wilsonville, AL. The test skid interfaces with a gasifier slipstream to deliver hot syngas to a parallel array of twelve SOFCs. During the 500 h test period, all twelve cells are monitored for performance at four current densities. Degradation is attributed to syngas exposure and trace material attack on the anode structure that is accelerated at increasing current densities. Cells that are operated at 0 and 125 mA cm{sup 2} degrade at 9.1 and 10.7% per 1000 h, respectively, while cells operated at 250 and 375 mA cm{sup 2} degrade at 18.9 and 16.2% per 1000 h, respectively. Spectroscopic analysis of the anodes showed carbon, sulfur, and phosphorus deposits; no secondary Ni-metal phases were found.

  12. Fuel nitrogen conversion and release of nitrogen oxides during coal gangue calcination.

    PubMed

    Zhang, Yingyi; Ge, Xinlei; Liu, Lili; Wang, Xidong; Zhang, Zuotai

    2015-05-01

    The pollution emission during the widespread utilization of coal gangue in construction industry has long been neglected. In present study, the NO x release behaviors in a simulation experiment of coal gangue calcination in construction industry were systematically investigated. The corresponding evolution of nitrogen functionalities in coal gangue was also discussed. Results showed that pyrrolic (N-5) and pyridine N-oxide (N-6-O) forms nitrogen were relatively abundant in the raw gangue. During calcination, the N-5 and N-6-O form nitrogen greatly decreased and converted to quaternary nitrogen (N-Q). It was found that NO2 was formed under slowly heating-up condition and at 600 °C under isothermal condition, while only NO was detected with further increase of temperature. From 600 to 1000 °C, the conversion ratio of fuel nitrogen to NO x increased from 8 to 12 %. The char nitrogen was found greatly contribute to NO formation, which may bring difficulty to the abatement of NO x emission during coal gangue calcination.

  13. Effect of coal ash on growth and metal uptake by some selected ectomycorrhizal fungi in vitro

    SciTech Connect

    Ray, P.; Reddy, U.G.; Lapeyrie, F.; Adholeya, A.

    2005-07-01

    Six isolates of ectomycorrhizal fungi namely, Laccaria fraterna (EM-1083), Pisolithus tinctorius (EM-1081), Pisolithus tinctorius (EM-1290), Pisolithus tinctorius (EM-1293), Scleroderma verucosurn (EM-1283), and Scleroderma cepa (EM-1233), were grown on three variants of coal ash, namely electrostatically precipitated (ESP) ash, pond ash, and bottom ash moistened with Modified Melin-Norkans (MMN) medium in vitro. The colony diameter reflected the growth of the isolates on the coal ash. Metal accumulation in the mycelia was assayed by atomic absorption spectrophotometry. Six metals, namely aluminum, cadmium, chromium, iron, lead, and nickel were selected on the basis of their abundance in coal ash and toxicity potential for the present work. Growth of vegetative mycelium on fly ash variants and metal accumulation data indicated that Pisolithus tinctorius (EM-1290) was the most tolerant among the isolates tested for most of the metals. Since this isolate is known to be mycorrhizal with Eucalyptus, it could be used for the reclamation of coal ash over burdened sites.

  14. OXIDATION OF MERCURY ACROSS SCR CATALYSTS IN COAL-FIRED POWER PLANTS BURNING LOW RANK FUELS

    SciTech Connect

    Constance Senior

    2004-12-31

    The objectives of this program were to measure the oxidation of mercury in flue gas across SCR catalyst in a coal-fired power plant burning low rank fuels using a slipstream reactor containing multiple commercial catalysts in parallel and to develop a greater understanding of mercury oxidation across SCR catalysts in the form of a simple model. The Electric Power Research Institute (EPRI) and Argillon GmbH provided co-funding for this program. REI used a multicatalyst slipstream reactor to determine oxidation of mercury across five commercial SCR catalysts at a power plant that burned a blend of 87% subbituminous coal and 13% bituminous coal. The chlorine content of the blend was 100 to 240 {micro}g/g on a dry basis. Mercury measurements were carried out when the catalysts were relatively new, corresponding to about 300 hours of operation and again after 2,200 hours of operation. NO{sub x}, O{sub 2} and gaseous mercury speciation at the inlet and at the outlet of each catalyst chamber were measured. In general, the catalysts all appeared capable of achieving about 90% NO{sub x} reduction at a space velocity of 3,000 hr{sup -1} when new, which is typical of full-scale installations; after 2,200 hours exposure to flue gas, some of the catalysts appeared to lose NO{sub x} activity. For the fresh commercial catalysts, oxidation of mercury was in the range of 25% to 65% at typical full-scale space velocities. A blank monolith showed no oxidation of mercury under any conditions. All catalysts showed higher mercury oxidation without ammonia, consistent with full-scale measurements. After exposure to flue gas for 2,200 hours, some of the catalysts showed reduced levels of mercury oxidation relative to the initial levels of oxidation. A model of Hg oxidation across SCRs was formulated based on full-scale data. The model took into account the effects of temperature, space velocity, catalyst type and HCl concentration in the flue gas.

  15. Recent advances in heterogeneous selective oxidation catalysis for sustainable chemistry.

    PubMed

    Guo, Zhen; Liu, Bin; Zhang, Qinghong; Deng, Weiping; Wang, Ye; Yang, Yanhui

    2014-05-21

    Oxidation catalysis not only plays a crucial role in the current chemical industry for the production of key intermediates such as alcohols, epoxides, aldehydes, ketones and organic acids, but also will contribute to the establishment of novel green and sustainable chemical processes. This review is devoted to dealing with selective oxidation reactions, which are important from the viewpoint of green and sustainable chemistry and still remain challenging. Actually, some well-known highly challenging chemical reactions involve selective oxidation reactions, such as the selective oxidation of methane by oxygen. On the other hand some important oxidation reactions, such as the aerobic oxidation of alcohols in the liquid phase and the preferential oxidation of carbon monoxide in hydrogen, have attracted much attention in recent years because of their high significance in green or energy chemistry. This article summarizes recent advances in the development of new catalytic materials or novel catalytic systems for these challenging oxidation reactions. A deep scientific understanding of the mechanisms, active species and active structures for these systems are also discussed. Furthermore, connections among these distinct catalytic oxidation systems are highlighted, to gain insight for the breakthrough in rational design of efficient catalytic systems for challenging oxidation reactions.

  16. SELECTIVE OXIDATION IN SUPERCRITICAL CARBON DIOXIDE USING CLEAN OXIDANTS

    EPA Science Inventory

    We have systematically investigated heterogeneous catalytic oxidation of different substrates in supercritical carbon dioxide (SC-CO2). Three types of catagysts: a metal complex, 0.5% platinum g-alumina and 0.5% palladium g-alumina were used at a pressure of 200 bar, temperatures...

  17. Co-Al mixed metal oxides/carbon nanotubes nanocomposite prepared via a precursor route and enhanced catalytic property

    SciTech Connect

    Fan Guoli; Wang Hui; Xiang Xu; Li Feng

    2013-01-15

    The present work reported the synthesis of Co-Al mixed metal oxides/carbon nanotubes (CoAl-MMO/CNT) nanocomposite from Co-Al layered double hydroxide/CNTs composite precursor (CoAl-LDH/CNT). The materials were characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM), low temperature nitrogen adsorption-desorption experiments, thermogravimetric and differential thermal analyses (TG-DTA), Raman spectra and X-ray photoelectron spectroscopy (XPS). The results revealed that in CoAl-MMO/CNT nanocomposite, the nanoparticles of cobalt oxide (CoO) and Co-containing spinel-type complex metal oxides could be well-dispersed on the surface of CNTs, thus forming the heterostructure of CoAl-MMO and CNTs. Furthermore, as-synthesized CoAl-MMO/CNT nanocomposite was utilized as additives for catalytic thermal decomposition of ammonium perchlorate (AP). Compared to those for pure AP and CoAl-MMO, the peak temperature of AP decomposition for CoAl-MMO/CNT was significantly decreased, which is attributed to the novel heterostructure and synergistic effect of multi-component metal oxides of nanocomposite. - Graphical abstract: Hybrid Co-Al mixed metal oxides/carbon nanotubes nanocomposite showed the enhanced catalytic activity in the thermal decomposition of ammonium perchlorate, as compared to carbon nanotubes and pure Co-Al mixed metal oxides. Highlights: Black-Right-Pointing-Pointer Co-Al mixed metal oxides/carbon nanotubes nanocomposite was synthesized. Black-Right-Pointing-Pointer Co-Al mixed metal oxides consisted of cobalt oxide and Co-containing spinels. Black-Right-Pointing-Pointer Nanocomposite exhibited excellent catalytic activity for the decomposition of AP. Black-Right-Pointing-Pointer The superior catalytic property is related to novel heterostructure and composition.

  18. OXIDATION OF MERCURY ACROSS SCR CATALYSTS IN COAL-FIRED POWER PLANTS BURNING LOW RANK FUELS

    SciTech Connect

    Constance Senior; Temi Linjewile

    2003-07-25

    This is the first Quarterly Technical Report for DOE Cooperative Agreement No: DE-FC26-03NT41728. The objective of this program is to measure the oxidation of mercury in flue gas across SCR catalyst in a coal-fired power plant burning low rank fuels using a slipstream reactor containing multiple commercial catalysts in parallel. The Electric Power Research Institute (EPRI) and Ceramics GmbH are providing co-funding for this program. This program contains multiple tasks and good progress is being made on all fronts. During this quarter, analysis of the coal, ash and mercury speciation data from the first test series was completed. Good agreement was shown between different methods of measuring mercury in the flue gas: Ontario Hydro, semi-continuous emission monitor (SCEM) and coal composition. There was a loss of total mercury across the commercial catalysts, but not across the blank monolith. The blank monolith showed no oxidation. The data from the first test series show the same trend in mercury oxidation as a function of space velocity that has been seen elsewhere. At space velocities in the range of 6,000-7,000 hr{sup -1} the blank monolith did not show any mercury oxidation, with or without ammonia present. Two of the commercial catalysts clearly showed an effect of ammonia. Two other commercial catalysts showed an effect of ammonia, although the error bars for the no-ammonia case are large. A test plan was written for the second test series and is being reviewed.

  19. Surface properties of photo-oxidized bituminous coals. Technical progress report, January--March 1996

    SciTech Connect

    Mitchell, G.; Davis, A.; Chander, S.

    1996-12-31

    During this report period, a vitrinite concentrate from the mvb Splash Dam seam (DECS-30) was prepared and analyzed. Results show that the concentrate was 91 vol % vitrinite and that the sample has been adequately protected from oxidation under refrigerated storage in argon. The 9% level of contamination within the vitrinite resulted from the extreme friability of the coal and to the dispersion of fine grains of semifusinite and micrinite. Polished blocks containing vitrain bands that were prepared, irradiated in blue-light and employed in contact angle measurements were evaluated using specular reflectance-mode FT-IR for changes in functional group chemistry. Infrared spectra from unexposed areas of vitrinite and those irradiated for 1, 5 and 10 min for six coals ranging in rank from hvCb to mvb were obtained using a FTS 175 spectrometer with a Bio-Rad UMA 500 microscope accessory. Preliminary results demonstrate that photo-oxidation occurred during irradiation, becoming progressively more intense with increasing irradiation time; however, the magnitude of this change diminished with increasing rank. A relatively steady increase in the carbonyl region (1,800--1,650 cm{sup {minus}1}) and a decrease in the aliphatic region (2,950--2,850 cm{sup {minus}1}) of the spectra supports this observation and is similar to observations made in the past for natural weathering and laboratory oxidation of coals. A series of tests was initiated to photo-oxidize powdered vitrains using the BLAK-RAY ultraviolet lamp evaluated last quarter. Samples of four vitrinite concentrates were exposed to UV light for 10 mins per side. These and the corresponding whole-seam channel samples and raw vitrinite concentrates were submitted for initial microflotation tests which have not been completed at this time.

  20. Semiconducting Metal Oxide Based Sensors for Selective Gas Pollutant Detection

    PubMed Central

    Kanan, Sofian M.; El-Kadri, Oussama M.; Abu-Yousef, Imad A.; Kanan, Marsha C.

    2009-01-01

    A review of some papers published in the last fifty years that focus on the semiconducting metal oxide (SMO) based sensors for the selective and sensitive detection of various environmental pollutants is presented. PMID:22408500

  1. Selective enrichment of phenols from coal liquefaction oil by solid phase extraction method

    SciTech Connect

    Tian, M.; Feng, J.

    2009-07-01

    This study focuses on the solid phase extraction method for the enrichment and separation of phenol from coal liquefaction oil. The phenols' separation efficiency was compared on different solid phase extraction (SPE) cartridges, and the effect of solvents with different polarity and solubility parameter on amino-bonded silica was compared for selection of optimal elution solution. The result showed that amino-bonded silica has the highest selectivity and best extraction capability due to two factors, weak anion exchange adsorption and polar attraction adsorption.

  2. Oxidative Dehydrogenative Couplings of Pyrazol-5-amines Selectively Forming Azopyrroles

    PubMed Central

    2015-01-01

    New oxidative dehydrogenative couplings of pyrazol-5-amines for the selective synthesis of azopyrrole derivatives have been described. The former reaction simultaneously installs C–I and N–N bonds through iodination and oxidation, whereas the latter involved a copper-catalyzed oxidative coupling process. The resulting iodo-substituted azopyrroles were employed by treatment with various terminal alkynes through Sonogashira cross-coupling leading to new azo compounds. PMID:24731223

  3. SELECTIVE OXIDATION OF ALCOHOLS OVER VANADIUM PHOSPHORUS OXIDE CATALYST USING HYDROGEN PEROXIDE

    EPA Science Inventory

    Oxidation of various alcohols is studied in liquid phase under nitrogen atmosphere over vanadium phosphorus oxide catalyst in an environmentally friendly protocol using hydrogen peroxide. The catalyst and the method are found to be suitable for the selective oxidation of a variet...

  4. Unprecedented Selective Oxidation of Styrene Derivatives using a Supported Iron Oxide Nanocatalyst in Aqueous Medium

    EPA Science Inventory

    Iron oxide nanoparticles supported on mesoporous silica-type materials have been successfully utilized in the aqueous selective oxidation of alkenes under mild conditions using hydrogen peroxide as a green oxidant. Catalysts could be easily recovered after completion of the reac...

  5. Characterization of solid reaction products from wet oxidation of pyrite in coal using alkaline solutions

    SciTech Connect

    Greer, R.T.; Markuszewski, R.; Wheelock, T.D.

    1980-01-01

    Oxidation of pyrite alone and pyrite embedded in coal by leaching with hot solutions of sodium carbonate containing dissolved oxygen under pressure produces hematite, the major solid reaction product. The hematite is deposited as a concentric rim surrounding the core of unreacted pyrite. The thickness of the rim is greater for products obtained after longer leaching time or under conditions of higher oxygen partial pressure. The product is identified as hematite by X-ray diffraction analysis. Data from scanning electron microscopy, and energy-dispersive X-ray analysis show that under these conditions of desulfurization, phase transformations occur (from pyrite to hematite). In addition, great differences in porosity of the two zones (core and rim) are observed. The nature and extent of these transformations are discussed in terms of the desulfurization potential of pyrite in coal. (10 refs.)

  6. Enzymatic desulfurization of coal

    SciTech Connect

    Boyer, Y.N.; Crooker, S.C.; Kitchell, J.P.; Nochur, S.V.

    1991-05-16

    The overall objective of this program was to investigate the feasibility of an enzymatic desulfurization process specifically intended for organic sulfur removal from coal. Toward that end, a series of specific objectives were defined: (1) establish the feasibility of (bio)oxidative pretreatment followed by biochemical sulfate cleavage for representative sulfur-containing model compounds and coals using commercially-available enzymes; (2) investigate the potential for the isolation and selective use of enzyme preparations from coal-utilizing microbial systems for desulfurization of sulfur-containing model compounds and coals; and (3) develop a conceptual design and economic analysis of a process for enzymatic removal of organic sulfur from coal. Within the scope of this program, it was proposed to carry out a portion of each of these efforts concurrently. (VC)

  7. Ti-STT: a new zeotype shape selective oxidation catalyst.

    PubMed

    Eilertsen, Einar André; Giordanino, Filippo; Lamberti, Carlo; Bordiga, Silvia; Damin, Alessandro; Bonino, Francesca; Olsbye, Unni; Lillerud, Karl Petter

    2011-11-21

    A new zeotype titanium silicate oxidation catalyst with the STT topology has been synthesized from direct synthesis. Ti-STT has a microporous structure with small pore openings, allowing shape selective oxidation catalysis. The isomorphous substitution of Si by Ti in the framework has been confirmed by Raman, FT-IR, UV-VIS and XANES spectroscopies.

  8. NHC-catalysed highly selective aerobic oxidation of nonactivated aldehydes

    PubMed Central

    Möhlmann, Lennart; Ludwig, Stefan

    2013-01-01

    Summary This publication describes a highly selective oxidation of aldehydes to the corresponding acids or esters. The reaction proceeds under metal-free conditions by using N-heterocyclic carbenes as organocatalysts in combination with environmentally friendly oxygen as the terminal oxidation agent. PMID:23616801

  9. Process for selected gas oxide removal by radiofrequency catalysts

    DOEpatents

    Cha, C.Y.

    1993-09-21

    This process to remove gas oxides from flue gas utilizes adsorption on a char bed subsequently followed by radiofrequency catalysis enhancing such removal through selected reactions. Common gas oxides include SO[sub 2] and NO[sub x]. 1 figure.

  10. The oxidative potential of PM10 from coal, briquettes and wood charcoal burnt in an experimental domestic stove

    NASA Astrophysics Data System (ADS)

    Shao, Longyi; Hou, Cong; Geng, Chunmei; Liu, Junxia; Hu, Ying; Wang, Jing; Jones, Tim; Zhao, Chengmei; BéruBé, Kelly

    2016-02-01

    Coal contains many potentially harmful trace elements. Coal combustion in unvented stoves, which is common in most parts of rural China, can release harmful emissions into the air that when inhaled cause health issues. However, few studies have dealt specifically with the toxicological mechanisms of the particulate matter (PM) released by coal and other solid fuel combustion. In this paper, PM10 particles that were generated during laboratory stove combustion of raw powdered coal, clay-mixed honeycomb briquettes, and wood charcoal were analysed for morphology, trace element compositions, and toxicity as represented by oxidative DNA damage. The analyses included Field Emission Scanning Electron Microscopy (FESEM), Inductively Coupled Plasma Mass Spectrometry (ICP-MS) and Plasmid Scission Assay (PSA). Gravimetric analysis indicated that the equivalent mass concentration of PM10 emitted by burning raw powdered coal was higher than that derived by burning honeycomb briquette. FESEM observation revealed that the coal burning-derived PM10 particles were mainly soot aggregates. The PSA results showed that the PM10 emitted by burning honeycomb briquettes had a higher oxidative capacity than that from burning raw powdered coal and wood charcoal. It is also demonstrated that the oxidative capacity of the whole particle suspensions were similar to those of the water soluble fractions; indicating that the DNA damage induced by coal burning-derived PM10 were mainly a result of the water-soluble fraction. An ICP-MS analysis revealed that the amount of total analysed water-soluble elements in the PM10 emitted by burning honeycomb briquettes was higher than that in PM produced by burning raw powdered coal, and both were higher than PM from burning wood charcoal. The total analysed water-soluble elements in these coal burning-derived PM10 samples had a significantly positive correlation with the level of DNA damage; indicating that the oxidative capacity of the coal burning

  11. Selective Electrocatalytic Activity of Ligand Stabilized Copper Oxide Nanoparticles

    SciTech Connect

    Kauffman, Douglas R; Ohodnicki, Paul R; Kail, Brian W; Matranga, Christopher

    2011-01-01

    Ligand stabilization can influence the surface chemistry of Cu oxide nanoparticles (NPs) and provide unique product distributions for electrocatalytic methanol (MeOH) oxidation and CO{sub 2} reduction reactions. Oleic acid (OA) stabilized Cu{sub 2}O and CuO NPs promote the MeOH oxidation reaction with 88% and 99.97% selective HCOH formation, respectively. Alternatively, CO{sub 2} is the only reaction product detected for bulk Cu oxides and Cu oxide NPs with no ligands or weakly interacting ligands. We also demonstrate that OA stabilized Cu oxide NPs can reduce CO{sub 2} into CO with a {approx}1.7-fold increase in CO/H{sub 2} production ratios compared to bulk Cu oxides. The OA stabilized Cu oxide NPs also show 7.6 and 9.1-fold increases in CO/H{sub 2} production ratios compared to weakly stabilized and non-stabilized Cu oxide NPs, respectively. Our data illustrates that the presence and type of surface ligand can substantially influence the catalytic product selectivity of Cu oxide NPs.

  12. The use of starch to enhance sulfur and ash removal from coal by selective oil agglomeration

    SciTech Connect

    Good, R.J.; Badgujar, M.N.

    1990-01-01

    We have found that the use of starch or gelatin, as an additive in the Otisca T-Process of selective oil agglomeration of coal, leads to a considerable improvement in the reduction of pyritic sulfur and of ash-forming minerals. A patent application has been filed; (Good Badgugar). Improvement in rejection of pyritic sulfur by up to 55% has been found, and improvement in ash rejection by up to 28%. Carbon recovery of 97.5 to 99.1% was obtained when the starch concentration was in the range, 30 to 200 ppM in the water. Three different bituminous coals were used: Upper Freeport, Kentucky No. 9, and Illinois No. 6.

  13. New Approach to Study the Ignition Processes of Organic Coal-Water Fuels in an Oxidizer Flow

    NASA Astrophysics Data System (ADS)

    Valiullin, T. R.; Dmitrienko, M. A.; Strizhak, P. A.

    2016-02-01

    To converge the conditions of organic water-coal fuel composition combustion in the typical power equipment we developed a new approach and installed an experimental setup, eliminating the traditional fixing the fuel droplets on the thermocouples or rods. Specialized cone-shaped chamber was used to implement the process of lingering of organic water-coal fuel droplets. Necessary and sufficient conditions for the lingering of organic water-coal fuel droplets were established. We determined the parameters of the system (droplet size of 0.4-0.6 mm, temperatures 823-903 K and the velocity of the oxidizer flow 1.5-6 m/s) at which the droplets were consistently ignited in the process of lingering. Minimum temperatures and ignition delay times of organic water-coal fuel droplets based on brown coal, used motor, turbine, transformer oils, kerosene, gasoline and water were defined.

  14. Molybdenum-based additives to mixed-metal oxides for use in hot gas cleanup sorbents for the catalytic decomposition of ammonia in coal gases

    DOEpatents

    Ayala, Raul E.

    1993-01-01

    This invention relates to additives to mixed-metal oxides that act simultaneously as sorbents and catalysts in cleanup systems for hot coal gases. Such additives of this type, generally, act as a sorbent to remove sulfur from the coal gases while substantially simultaneously, catalytically decomposing appreciable amounts of ammonia from the coal gases.

  15. Selected elements in major minerals from bituminous coal as determined by INAA: Implications for removing environmentally sensitive elements from coal

    USGS Publications Warehouse

    Palmer, C.A.; Lyons, P.C.

    1996-01-01

    The four most abundant minerals generally found in Euramerican bituminous coals are quartz, kaolinite, illite and pyrite. These four minerals were isolated by density separation and handpicking from bituminous coal samples collected in the Ruhr Basin, Germany and the Appalachian basin, U.S.A. Trace-element concentrations of relatively pure (??? 99+%) separates of major minerals from these coals were determined directly by using instrumental neutron activation analysis (INAA). As expected, quartz contributes little to the trace-element mass balance. Illite generally has higher trace-element concentrations than kaolinite, but, for the concentrates analyzed in this study, Hf, Ta, W, Th and U are in lower concentrations in illite than in kaolinite. Pyrite has higher concentrations of chalcophile elements (e.g., As and Se) and is considerably lower in lithophile elements as compared to kaolinite and illite. Our study provides a direct and sensitive method of determining trace-element relationships with minerals in coal. Mass-balance calculations suggest that the trace-element content of coal can be explained mainly by three major minerals: pyrite, kaolinite and illite. This conclusion indicates that the size and textural relationships of these major coal minerals may be a more important consideration as to whether coal cleaning can effectively remove the most environmentally sensitive trace elements in coal than what trace minerals are present.

  16. Selective Electrochemical versus Chemical Oxidation of Bulky Phenol.

    PubMed

    Zabik, Nicole L; Virca, Carolyn N; McCormick, Theresa M; Martic-Milne, Sanela

    2016-09-01

    The electrochemical oxidation of selected tert-butylated phenols 2,6-di-tert-butyl-4-methylphenol (1), 2,6-di-tert-butylphenol (2), 2,4,6-tri-tert-butylphenol (3), 2-tert-butylphenol (4), and 4-tert-butylphenol (5) was studied in an aprotic environment using cyclic voltammetry, square-wave voltammetry, and UV-vis spectroscopy. All compounds exhibited irreversible oxidation of the corresponding phenol or phenolate ion. Compound 2 was selectively electrochemically oxidized, while other phenol analogues underwent mostly chemical oxidation. The electrochemical oxidation of 2 produced a highly absorbing product, 3,5,3',5'-tetra-tert-butyl-4,4'-diphenoquinone, which was characterized by X-ray crystal diffraction. The electrochemical oxidation was monitored as a function of electrochemical parameters and concentration. Experimental and theoretical data indicated that the steric hindrance, phenoxyl radical stability, and hydrogen bonding influenced the outcome of the electrochemical oxidation. The absence of the substituent at the para position and the presence of the bulky substituents at ortho positions were structural and electrostatic requirements for the selective electrochemical oxidation.

  17. Selective Electrochemical versus Chemical Oxidation of Bulky Phenol.

    PubMed

    Zabik, Nicole L; Virca, Carolyn N; McCormick, Theresa M; Martic-Milne, Sanela

    2016-09-01

    The electrochemical oxidation of selected tert-butylated phenols 2,6-di-tert-butyl-4-methylphenol (1), 2,6-di-tert-butylphenol (2), 2,4,6-tri-tert-butylphenol (3), 2-tert-butylphenol (4), and 4-tert-butylphenol (5) was studied in an aprotic environment using cyclic voltammetry, square-wave voltammetry, and UV-vis spectroscopy. All compounds exhibited irreversible oxidation of the corresponding phenol or phenolate ion. Compound 2 was selectively electrochemically oxidized, while other phenol analogues underwent mostly chemical oxidation. The electrochemical oxidation of 2 produced a highly absorbing product, 3,5,3',5'-tetra-tert-butyl-4,4'-diphenoquinone, which was characterized by X-ray crystal diffraction. The electrochemical oxidation was monitored as a function of electrochemical parameters and concentration. Experimental and theoretical data indicated that the steric hindrance, phenoxyl radical stability, and hydrogen bonding influenced the outcome of the electrochemical oxidation. The absence of the substituent at the para position and the presence of the bulky substituents at ortho positions were structural and electrostatic requirements for the selective electrochemical oxidation. PMID:27454828

  18. Cooperative Catalysis for Selective Alcohol Oxidation with Molecular Oxygen.

    PubMed

    Slot, Thierry K; Eisenberg, David; van Noordenne, Dylan; Jungbacker, Peter; Rothenberg, Gadi

    2016-08-22

    The activation of dioxygen for selective oxidation of organic molecules is a major catalytic challenge. Inspired by the activity of nitrogen-doped carbons in electrocatalytic oxygen reduction, we combined such a carbon with metal-oxide catalysts to yield cooperative catalysts. These simple materials boost the catalytic oxidation of several alcohols, using molecular oxygen at atmospheric pressure and low temperature (80 °C). Cobalt and copper oxide demonstrate the highest activities. The high activity and selectivity of these catalysts arises from the cooperative action of their components, as proven by various control experiments and spectroscopic techniques. We propose that the reaction should not be viewed as occurring at an 'active site', but rather at an 'active doughnut'-the volume surrounding the base of a carbon-supported metal-oxide particle.

  19. Monolithic solid oxide fuel cell technology advancement for coal- based power generation. Quarterly report, December 1991

    SciTech Connect

    Not Available

    1992-01-15

    The program is conducted by a team consisting of AiResearch Los Angeles Division of Allied-Signal Aerospace Company and Argonne National Laboratory (ANL). The objective of the program is to advance materials and fabrication methodologies to develop a monolithic solid oxide fuel cell (MSOFC) system capable of meeting performance, life, and cost goals for coal-based power generation. The program focuses on materials research and development, fabrication process development, cell/stack performance testing and characterization, cost and system analysis, and quality development.

  20. Monolithic solid oxide fuel cell technology advancement for coal- based power generation

    SciTech Connect

    Not Available

    1992-01-15

    The program is conducted by a team consisting of AiResearch Los Angeles Division of Allied-Signal Aerospace Company and Argonne National Laboratory (ANL). The objective of the program is to advance materials and fabrication methodologies to develop a monolithic solid oxide fuel cell (MSOFC) system capable of meeting performance, life, and cost goals for coal-based power generation. The program focuses on materials research and development, fabrication process development, cell/stack performance testing and characterization, cost and system analysis, and quality development.

  1. Two Catalysts for Selective Oxidation of Contaminant Gases

    NASA Technical Reports Server (NTRS)

    Wright, John D.

    2011-01-01

    Two catalysts for the selective oxidation of trace amounts of contaminant gases in air have been developed for use aboard the International Space Station. These catalysts might also be useful for reducing concentrations of fumes in terrestrial industrial facilities especially facilities that use halocarbons as solvents, refrigerant liquids, and foaming agents, as well as facilities that generate or utilize ammonia. The first catalyst is of the supported-precious-metal type. This catalyst is highly active for the oxidation of halocarbons, hydrocarbons, and oxygenates at low concentrations in air. This catalyst is more active for the oxidation of hydrocarbons and halocarbons than are competing catalysts developed in recent years. This catalyst completely converts these airborne contaminant gases to carbon dioxide, water, and mineral acids that can be easily removed from the air, and does not make any chlorine gas in the process. The catalyst is thermally stable and is not poisoned by chlorine or fluorine atoms produced on its surface during the destruction of a halocarbon. In addition, the catalyst can selectively oxidize ammonia to nitrogen at a temperature between 200 and 260 C, without making nitrogen oxides, which are toxic. The temperature of 260 C is higher than the operational temperature of any other precious-metal catalyst that can selectively oxidize ammonia. The purpose of the platinum in this catalyst is to oxidize hydrocarbons and to ensure that the oxidation of halocarbons goes to completion. However, the platinum exhibits little or no activity for initiating the destruction of halocarbons. Instead, the attack on the halocarbons is initiated by the support. The support also provides a high surface area for exposure of the platinum. Moreover, the support resists deactivation or destruction by halogens released during the destruction of halocarbons. The second catalyst is of the supported- metal-oxide type. This catalyst can selectively oxidize ammonia to

  2. Evaluation of reaction mechanism of coal-metal oxide interactions in chemical-looping combustion

    SciTech Connect

    Siriwardane, Ranjani; Richards, George; Poston, James; Tian, Hanjing; Miller, Duane; Simonyi, Thomas

    2010-11-15

    The knowledge of reaction mechanism is very important in designing reactors for chemical-looping combustion (CLC) of coal. Recent CLC studies have considered the more technically difficult problem of reactions between abundant solid fuels (i.e. coal and waste streams) and solid metal oxides. A definitive reaction mechanism has not been reported for CLC reaction of solid fuels. It has often been assumed that the solid/solid reaction is slow and therefore requires that reactions be conducted at temperatures high enough to gasify the solid fuel, or decompose the metal oxide. In contrast, data presented in this paper demonstrates that solid/solid reactions can be completed at much lower temperatures, with rates that are technically useful as long as adequate fuel/metal oxide contact is achieved. Density functional theory (DFT) simulations as well as experimental techniques such as thermo-gravimetric analysis (TGA), flow reactor studies, in situ X-ray photo electron spectroscopy (XPS), in situ X-ray diffraction (XRD) and scanning electron microscopy (SEM) are used to evaluate how the proximal interaction between solid phases proceeds. The data indicate that carbon induces the Cu-O bond breaking process to initiate the combustion of carbon at temperatures significantly lower than the spontaneous decomposition temperature of CuO, and the type of reducing medium in the vicinity of the metal oxide influences the temperature at which the oxygen release from the metal oxide takes place. Surface melting of Cu and wetting of carbon may contribute to the solid-solid contacts necessary for the reaction. (author)

  3. Understanding mercury transformations in coal-fired power plants: evaluation of homogeneous Hg oxidation mechanisms

    SciTech Connect

    Balaji Krishnakumar; Joseph J. Helble

    2007-11-15

    Homogeneous mercury oxidation mechanisms described by Niksa and Qiu, and three theoretical mercury oxidation reaction rate constants developed by Wilcox were evaluated for their predictions of the extent of mercury oxidation under coal combustion conditions. Predictions were compared to results from bench-scale experiments to determine whether such models were suitable for predicting measured levels of homogeneous mercury oxidation. Experiments considered different flue gas compositions and quench rates to provide a broad range of conditions for analysis. Most mercury oxidation was predicted to occur at temperatures below 900 K. The Niksa mechanism predicted Hg oxidation to occur only in systems that were close to isothermal at temperatures above 900 K followed by a rapid gas quench. This mechanism provided the best agreement with the experimental data of Sliger. The Qiu mechanism predicted Hg oxidation in several experimental systems and conditions fairly accurately although it did not provide the best agreement in all cases. Qiu mechanism predictions for the experimental system at the University of Connecticut operating at an equivalence ratio of 0.9 in the presence of HCl/Cl{sub 2} and also SO{sub 2} were within the bounds of experimental uncertainty. The effects of flue gas composition and quench on Hg oxidation are qualitatively represented by the Qiu mechanism suggesting a relative robustness of the model, although there is still need to refine rate constants to achieve greater accuracy. The Wilcox rate constants when substituted in the Qiu mechanism predicted near-complete oxidation of Hg irrespective of HCl concentrations in systems that involve flue gas quench below temperatures of 450 K. 22 refs., 5 figs., 1 tab.

  4. Understanding mercury transformations in coal-fired power plants: evaluation of homogeneous Hg oxidation mechanisms.

    PubMed

    Krishnakumar, Balaji; Helble, Joseph J

    2007-11-15

    Homogeneous mercury oxidation mechanisms described by Niksa and Qiu, and three theoretical mercury oxidation reaction rate constants developed by Wilcox were evaluated for their predictions of the extent of mercury oxidation under coal combustion conditions. Predictions were compared to results from bench-scale experiments to determine whether such models were suitable for predicting measured levels of homogeneous mercury oxidation. Experiments considered different flue gas compositions (O2, Cl, NO, and SO2) and quench rates to provide a broad range of conditions for analysis. Regardless of the mechanism chosen, most mercury oxidation was predicted to occur at temperatures below 900 K. The Niksa mechanism predicted Hg oxidation to occur only in systems that were close to isothermal at temperatures above 900 K followed by a rapid gas quench. This mechanism provided the best agreement with the experimental data of Sliger. The Qiu mechanism predicted Hg oxidation in several experimental systems and conditions fairly accurately although it did not provide the best agreement in all cases. Qiu mechanism predictions for the experimental system at the University of Connecticut operating at an equivalence ratio of 0.9 in the presence of HCl/Cl2 and also SO2 were within the bounds of experimental uncertainty. Additionally, for an experimental dataset obtained from the University of Utah for quench rates of 210 and 440 K/s in the presence of HCI, the Qiu model predicted the experimental observations with a high degree of accuracy. The effects of flue gas composition and quench on Hg oxidation are qualitatively represented by the Qiu mechanism suggesting a relative robustness of the model, although there is still need to refine rate constants to achieve greater accuracy. The Wilcox rate constants when substituted in the Qiu mechanism predicted near-complete oxidation of Hg irrespective of HCl concentrations in systems that involve flue gas quench below temperatures of 450 K.

  5. Catalytic coal liquefaction process

    DOEpatents

    Garg, D.; Sunder, S.

    1986-12-02

    An improved process for catalytic solvent refining or hydroliquefaction of non-anthracitic coal at elevated temperatures under hydrogen pressure in a solvent comprises using as catalyst a mixture of a 1,2- or 1,4-quinone and an alkaline compound, selected from ammonium, alkali metal, and alkaline earth metal oxides, hydroxides or salts of weak acids. 1 fig.

  6. Catalytic coal liquefaction process

    DOEpatents

    Garg, Diwakar; Sunder, Swaminathan

    1986-01-01

    An improved process for catalytic solvent refining or hydroliquefaction of non-anthracitic coal at elevated temperatures under hydrogen pressure in a solvent comprises using as catalyst a mixture of a 1,2- or 1,4-quinone and an alkaline compound, selected from ammonium, alkali metal, and alkaline earth metal oxides, hydroxides or salts of weak acids.

  7. Method For Selective Catalytic Reduction Of Nitrogen Oxides

    DOEpatents

    Mowery-Evans, Deborah L.; Gardner, Timothy J.; McLaughlin, Linda I.

    2005-02-15

    A method for catalytically reducing nitrogen oxide compounds (NO.sub.x, defined as nitric oxide, NO, +nitrogen dioxide, NO.sub.2) in a gas by a material comprising a base metal consisting essentially of CuO and Mn, and oxides of Mn, on an activated metal hydrous metal oxide support, such as HMO:Si. A promoter, such as tungsten oxide or molybdenum oxide, can be added and has been shown to increase conversion efficiency. This method provides good conversion of NO.sub.x to N.sub.2, good selectivity, good durability, resistance to SO.sub.2 aging and low toxicity compared with methods utilizing vanadia-based catalysts.

  8. Method for selective catalytic reduction of nitrogen oxides

    DOEpatents

    Mowery-Evans, Deborah L.; Gardner, Timothy J.; McLaughlin, Linda I.

    2005-02-15

    A method for catalytically reducing nitrogen oxide compounds (NO.sub.x, defined as nitric oxide, NO, +nitrogen dioxide, NO.sub.2) in a gas by a material comprising a base metal consisting essentially of CuO and Mn, and oxides of Mn, on an activated metal hydrous metal oxide support, such as HMO:Si. A promoter, such as tungsten oxide or molybdenum oxide, can be added and has been shown to increase conversion efficiency. This method provides good conversion of NO.sub.x to N.sub.2, good selectivity, good durability, resistance to SO.sub.2 aging and low toxicity compared with methods utilizing vanadia-based catalysts.

  9. Coal Ash Resources Research Consortium. Annual report and selected publications, 1 July 1992--30 June 1993

    SciTech Connect

    Pflughoeft-Hassett, D.F.; Dockter, B.A.; Eylands, K.E.; Hassett, D.J.; O`Leary, E.M.

    1994-04-01

    The Coal Ash Resources Research Consortium (CARRC, pronounced cars), formerly the Western Fly Ash Research, Development, and Data Center (WFARDDC), has continued fundamental and applied scientific and engineering research focused on promoting environmentally safe, economical use of coal combustion fly ash. The research tasks selected for the year included: (1) Coal Ash Properties Database Maintenance and Expansion, (2) Investigation of the High-Volume Use of Fly Ash for Flowable Backfill Applications, (3) Investigation of Hydrated Mineralogical Phases in Coal Combustion By-Products, (4) Comparison of Department of Transportation Specifications for Coal Ash Utilization, (5) Comparative Leaching Study of Coal Combustion By-Products and Competing Construction Materials, (6) Application of CCSEM for Coal Ash Characterization, (7) Determination of Types and Causes of Efflorescence in Regional Concrete Products, and (8) Sulfate Resistance of Fly Ash Concrete: A Literature Review and Evaluation of Research Priorities. The assembly of a database of information on coal fly ash has been a focus area for CARRC since its beginning in 1985. This year, CARRC members received an updated run time version of the Coal Ash Properties Database (CAPD) on computer disk for their use. The new, user-friendly database management format was developed over the year to facilitate the use of CAPD by members as well as CARRC researchers. It is anticipated that this direct access to CAPD by members as well as CARRC researchers. It is anticipated that this direct access to CAPD by members will be beneficial to each company`s utilization efforts, to CARRC, and to the coal ash industry in general. Many additions and improvements were made to CAPD during the year, and a three-year plan for computer database and modeling related to coal ash utilization was developed to guide both the database effort and the research effort.

  10. Effect of selective catalytic reduction (SCR) on fine particle emission from two coal-fired power plants in China

    NASA Astrophysics Data System (ADS)

    Li, Zhen; Jiang, Jingkun; Ma, Zizhen; Wang, Shuxiao; Duan, Lei

    2015-11-01

    Nitrogen oxides (NOx) emission abatement of coal-fired power plants (CFPPs) requires large-scaled installation of selective catalytic reduction (SCR), which would reduce secondary fine particulate matter (PM2.5) (by reducing nitrate aerosol) in the atmosphere. However, our field measurement of two CFPPs equipped with SCR indicates a significant increase of SO42- and NH4+ emission in primary PM2.5, due to catalytic enhancement of SO2 oxidation to SO3 and introducing of NH3 as reducing agent. The subsequent formation of (NH4)2SO4 or NH4HSO4 aerosol is commonly concentrated in sub-micrometer particulate matter (PM1) with a bimodal pattern. The measurement at the inlet of stack also showed doubled primary PM2.5 emission by SCR operation. This effect should therefore be considered when updating emission inventory of CFPPs. By rough estimation, the enhanced primary PM2.5 emission from CFPPs by SCR operation would offset 12% of the ambient PM2.5 concentration reduction in cities as the benefit of national NOx emission abatement, which should draw attention of policy-makers for air pollution control.

  11. Selective edge modification in graphene and graphite by chemical oxidation.

    PubMed

    Yang, Min; Moriyama, Satoshi; Higuchi, Masayoshi

    2014-04-01

    The effect of edge structures in graphene sheets has been well investigated theoretically but most experimental demonstrations of the functionalization have been for the bulk structures because of only a few reports on chemical methods to modify the edges selectively. We herein report a chemical method using the Lemieux-von Rudloff reagent that selectively oxidizes only the edges of graphene sheets. The selective oxidation at the edges of the graphene sheet was confirmed by thermogravimetric analysis (TGA), Raman mapping measurements, and X-ray photoelectron spectroscopy (XPS). The TGA result of the oxidized graphite with different particle sizes showed a slight weight loss at approximately 350 degrees C (2.29% for the middle particles (35 microm)), which indicates thermal decomposition of the oxidized edge part. The Raman mapping measurement in the inner part of graphene sheets didn't detect any defects or translational symmetry breaking after the oxidation. The XPS data clearly showed that the total carbon atom content present as C--O, C==O, and O--C==C increased from 4.65 to 6.18% by the oxidation. Using the obtained edge-oxidized graphene as a starting material, various functionalizations of the edge structure are expected in the future.

  12. Method and reaction pathway for selectively oxidizing organic compounds

    DOEpatents

    Camaioni, Donald M.; Lilga, Michael A.

    1998-01-01

    A method of selectively oxidizing an organic compound in a single vessel comprises: a) combining an organic compound, an acid solution in which the organic compound is soluble, a compound containing two oxygen atoms bonded to one another, and a metal ion reducing agent capable of reducing one of such oxygen atoms, and thereby forming a mixture; b) reducing the compound containing the two oxygen atoms by reducing one of such oxygen atoms with the metal ion reducing agent to, 1) oxidize the metal ion reducing agent to a higher valence state, and 2) produce an oxygen containing intermediate capable of oxidizing the organic compound; c) reacting the oxygen containing intermediate with the organic compound to oxidize the organic compound into an oxidized organic intermediate, the oxidized organic intermediate having an oxidized carbon atom; d) reacting the oxidized organic intermediate with the acid counter ion and higher valence state metal ion to bond the acid counter ion to the oxidized carbon atom and thereby produce a quantity of an ester incorporating the organic intermediate and acid counter ion; and e) reacting the oxidized organic intermediate with the higher valence state metal ion and water to produce a quantity of alcohol which is less than the quantity of ester, the acid counter ion incorporated in the ester rendering the carbon atom bonded to the counter ion less reactive with the oxygen containing intermediate in the mixture than is the alcohol with the oxygen containing intermediate.

  13. Oxidation resistance of selected mechanical carbons at 650 deg C in dry flowing air

    NASA Technical Reports Server (NTRS)

    Allen, G. P.; Wisander, D. W.

    1973-01-01

    Oxidation experiments were conducted with several experimental mechanical carbons at 650 C in air flowing at 28 cu cm/sec (STP). Experiments indicate that boron carbide addition and zinc phosphate treatment definitely improved oxidation resistance. Impregnation with coal tar pitch before final graphitization had some beneficial effect on oxidation resistance and it markedly improved flexure strength and hardness. Graphitization temperature alone did not affect oxidation resistance, but with enough added boron carbide the oxidation resistance was increased although the hardness greatly decreased.

  14. Performance of solid oxide fuel cells operated with coal syngas provided directly from a gasification process

    SciTech Connect

    Hackett, Gregory A.; Gerdes, Kirk R.; Song, Xueyan; Chen, Yun; Shutthanandan, V.; Engelhard, Mark H.; Zhu, Zihua; Thevuthasan, Suntharampillai; Gemmen, Randall

    2012-09-15

    Solid oxide fuel cells (SOFCs) are presently being developed for gasification integrated power plants that generate electricity from coal at 50+% efficiency. The interaction of trace metals in coal syngas with the Ni-based SOFC anodes is being investigated through thermodynamic analyses and in laboratory experiments, but direct test data from coal syngas exposure are sparsely available. This research effort evaluates the significance of SOFC performance losses associated with exposure of a SOFC anode to direct coal syngas. SOFC specimen of industrially relevant composition are operated in a unique mobile test skid that was deployed to the research gasifier at the National Carbon Capture Center (NCCC) in Wilsonville, AL. The mobile test skid interfaces with a gasifier slipstream to deliver hot syngas (up to 300°C) directly to a parallel array of 12 button cell specimen, each of which possesses an active area of approximately 2 cm2. During the 500 hour test period, all twelve cells were monitored for performance at four discrete operating current densities, and all cells maintained contact with a data acquisition system. Of these twelve, nine demonstrated good performance throughout the test, while three of the cells were partially compromised. Degradation associated with the properly functioning cells was attributed to syngas exposure and trace material attack on the anode structure that was accelerated at increasing current densities. Cells that were operated at 0 and 125 mA/cm² degraded at 9.1 and 10.7% per 1000 hours, respectively, while cells operated at 250 and 375 mA/cm² degraded at 18.9 and 16.2% per 1000 hours, respectively. Post-trial spectroscopic analysis of the anodes showed carbon, sulfur, and phosphorus deposits; no secondary Ni-metal phases were found.

  15. Structural features of a bituminous coal and their changes during low-temperature oxidation and loss of volatiles investigated by advanced solid-state NMR spectroscopy

    USGS Publications Warehouse

    Mao, J.-D.; Schimmelmann, A.; Mastalerz, Maria; Hatcher, P.G.; Li, Y.

    2010-01-01

    Quantitative and advanced 13C solid-state NMR techniques were employed to investigate (i) the chemical structure of a high volatile bituminous coal, as well as (ii) chemical structural changes of this coal after evacuation of adsorbed gases, (iii) during oxidative air exposure at room temperature, and (iv) after oxidative heating in air at 75 ??C. The solid-state NMR techniques employed in this study included quantitative direct polarization/magic angle spinning (DP/MAS) at a high spinning speed of 14 kHz, cross polarization/total sideband suppression (CP/TOSS), dipolar dephasing, CH, CH2, and CHn selection, 13C chemical shift anisotropy (CSA) filtering, two-dimensional (2D) 1H-13C heteronuclear correlation NMR (HETCOR), and 2D HETCOR with 1H spin diffusion. With spectral editing techniques, we identified methyl CCH 3, rigid and mobile methylene CCH2C, methine CCH, quaternary Cq, aromatic CH, aromatic carbons bonded to alkyls, small-sized condensed aromatic moieties, and aromatic C-O groups. With direct polarization combined with spectral-editing techniques, we quantified 11 different types of functional groups. 1H-13C 2D HETCOR NMR experiments indicated spatial proximity of aromatic and alkyl moieties in cross-linked structures. The proton spin diffusion experiments indicated that the magnetization was not equilibrated at a 1H spin diffusion time of 5 ms. Therefore, the heterogeneity in spatial distribution of different functional groups should be above 2 nm. Recoupled C-H long-range dipolar dephasing showed that the fraction of large charcoal-like clusters of polycondensed aromatic rings was relatively small. The exposure of this coal to atmospheric oxygen at room temperature for 6 months did not result in obvious chemical structural changes of the coal, whereas heating at 75 ??C in air for 10 days led to oxidation of coal and generated some COO groups. Evacuation removed most volatiles and caused a significant reduction in aliphatic signals in its DP

  16. Microbial Oxidation of Ethane within Seep Sediment at Coal Oil Point, Santa Barbara, CA

    NASA Astrophysics Data System (ADS)

    Mendes, S. D.; Duncombe, R.; Scarlett, R. D.; Shaffer, J.; Lensch, S.; Valentine, D. L.

    2013-12-01

    The hydrocarbon seep field at Coal Oil Point (COP), off the coast of Santa Barbara, California, releases more than 10^10 g of thermogenic natural gas each year. Only a fraction of this methane, ethane, propane, and butane reaches the atmosphere, and is instead consumed by marine microbes in both the sediment and water column. Bacterial respiration of these gases has been observed in aerobic and anaerobic conditions, with the exception of ethane (aerobic only) (Kniemeyer et. al 2007). This work seeks to quantify the rate of ethane oxidation (both aerobic and anaerobic) in marine sediment. A series of experiments, to be conducted using COP seep sediment aboard the R/V Atlantis in October 2013, will test how varying oxygen conditions impact ethane oxidation rate. Oxidation rates will be quantified using sensitive 3H-ethane tracers. Preliminary data from Shane's Seep, located within the COP seep field, indicates that ethane oxidation is restricted to the top 6 cm of sediment. This suggests that oxygen is a limiting factor, but further work is needed to establish if ethane oxidation is restricted to exclusively aerobic environments.

  17. Boiler materials for ultra-supercritical coal power plants—Steamside oxidation

    NASA Astrophysics Data System (ADS)

    Viswanathan, R.; Sarver, J.; Tanzosh, J. M.

    2006-06-01

    The corrosion behavior of tubing materials carrying steam at high temperature is of great concern to fossil power plant operators. This is due to the fact that the oxide films formed on the steam side can lead to major failures and consequently to reduced plant availability. The wall loss of the pressure boundary caused by oxidation can increase the hoop stresses and cause premature creep failures; second, the increased insulation of the tubes due to the low thermal conductivity of the oxide film can lead to increased metal temperature, thereby exacerbating the fireside corrosion as well as creep problems. The third concern is that thicker oxides may spall more easily when the plant is cooled down. On restart, the spalled material may lodge somewhere in the system with the potential for causing tube blockages, or it may be swept out with the working fluid and enter the steam turbine causing erosion damage to the turbine nozzles and blades. Failures of tubing and turbine components by these mechanisms have been widely reported in the United States. In view of the importance of the steamside oxidation, a major study of the phenomenon is being carried out as part of a major national program sponsored by the U.S. Department of Energy and the Ohio Coal Development Office. As a prelude to the experimental work, a literature survey was performed to document the state of the art. Results of the review are reported here.

  18. Removal of oxides of nitrogen from gases in multi-stage coal combustion

    SciTech Connect

    Mollot, D.J.; Bonk, D.L.; Dowdy, T.E.

    1996-12-31

    Polluting NO{sub x} gas values are removed from off-gas of a multi-stage coal combustion process which includes an initial carbonizing reaction, firing of char from this reaction in a fluidized bed reactor, and burning of gases from the carbonizing and fluidized bed reactions in a topping combustor having a first, fuel-rich zone and a second, fuel-lean zone. The improvement by means of which NO{sub x} gases are removed is directed to introducing NO{sub x}-free oxidizing gas such as compressor air into the second, fuel-lean zone and completing combustion with this source of oxidizing gas. Excess air fed to the fluidized bed reactor is also controlled to obtain desired stoichiometry in the first, fuel-rich zone of the topping combustor.

  19. MINIMIZING NET CO2 EMISSIONS BY OXIDATIVE CO-PYROLYSIS OF COAL / BIOMASS BLENDS

    SciTech Connect

    Todd Lang; Robert Hurt

    2001-12-23

    This study presents a set of thermodynamic calculations on the optimal mode of solid fuel utilization considering a wide range of fuel types and processing technologies. The technologies include stand-alone combustion, biomass/coal cofiring, oxidative pyrolysis, and straight carbonization with no energy recovery but with elemental carbon storage. The results show that the thermodynamically optimal way to process solid fuels depends strongly on the specific fuels and technologies available, the local demand for heat or for electricity, and the local baseline energy-production method. Burning renewable fuels reduces anthropogenic CO{sub 2} emissions as widely recognized. In certain cases, however, other processing methods are equally or more effective, including the simple carbonization or oxidative pyrolysis of biomass fuels.

  20. Removal of oxides of nitrogen from gases in multi-stage coal combustion

    DOEpatents

    Mollot, Darren J.; Bonk, Donald L.; Dowdy, Thomas E.

    1998-01-01

    Polluting NO.sub.x gas values are removed from off-gas of a multi-stage coal combustion process which includes an initial carbonizing reaction, firing of char from this reaction in a fluidized bed reactor, and burning of gases from the carbonizing and fluidized bed reactions in a topping combustor having a first, fuel-rich zone and a second, fuel-lean zone. The improvement by means of which NO.sub.x gases are removed is directed to introducing NO.sub.x -free oxidizing gas such as compressor air into the second, fuel-lean zone and completing combustion with this source of oxidizing gas. Excess air fed to the fluidized bed reactor is also controlled to obtain desired stoichiometry in the first, fuel-rich zone of the topping combustor.

  1. Removal of oxides of nitrogen from gases in multi-stage coal combustion

    DOEpatents

    Mollot, D.J.; Bonk, D.L.; Dowdy, T.E.

    1998-01-13

    Polluting NO{sub x} gas values are removed from off-gas of a multi-stage coal combustion process which includes an initial carbonizing reaction, firing of char from this reaction in a fluidized bed reactor, and burning of gases from the carbonizing and fluidized bed reactions in a topping combustor having a first, fuel-rich zone and a second, fuel-lean zone. The improvement by means of which NO{sub x} gases are removed is directed to introducing NO{sub x}-free oxidizing gas such as compressor air into the second, fuel-lean zone and completing combustion with this source of oxidizing gas. Excess air fed to the fluidized bed reactor is also controlled to obtain desired stoichiometry in the first, fuel-rich zone of the topping combustor. 2 figs.

  2. Heavy-metal content and oxidative damage in Hypsiboas faber: the impact of coal-mining pollutants on amphibians.

    PubMed

    Zocche, Jairo José; da Silva, Luciano Acordi; Damiani, Adriani Paganini; Mendonça, Rodrigo Ávila; Peres, Poliana Bernardo; dos Santos, Carla Eliete Iochims; Debastiani, Rafaela; Dias, Johnny Ferraz; de Andrade, Vanessa Moraes; Pinho, Ricardo Aurino

    2014-01-01

    It has been identified worldwide that amphibians are experiencing massive population declines. This decrease could be further enhanced by the exposure of amphibians to pollutants, which would enhance reactive oxygen species production and cause subsequent alterations in oxidant defense levels. The present study was aimed at understanding the impact of mineral coal on amphibians. For this purpose, chemical elemental contents and oxidative stress indexes in Hypsiboas faber from coal-mining areas and in an unpolluted area in the Catarinense Coal Basin, Brazil, were assessed. The highest contents of sulfur, chlorine, iron, zinc, and bromine were registered in specimens from the coal-mining area, whereas the highest contents of potassium calcium, and silicon were registered in specimens from the control area. It was found that there was a significant increase (p < 0.05) in the activity of super oxide dismutase (SOD) and glutathione peroxidase (GPx) in the animals from the coal-mining area, whereas the level of catalase showed no differences between the animal groups. The levels of TBARS showed no differences between the tested groups. However, carbonylation decreased significantly (p < 0.05) in animals from the coal-mining area, and there was a significant increase (p < 0.05) in the formation of total thiols in animals from the coal-mining area. In conclusion, the antioxidant system of H. faber is sensitive to pollutants present in coal-mining wastes, and its SOD and GPx activity may be a potential biomarker for monitoring the level of contaminants in the environment.

  3. Selective aerobic oxidation mediated by TiO(2) photocatalysis.

    PubMed

    Lang, Xianjun; Ma, Wanhong; Chen, Chuncheng; Ji, Hongwei; Zhao, Jincai

    2014-02-18

    TiO2 is one of the most studied metal oxide photocatalysts and has unparal-leled efficiency and stability. This cheap, abundant, and non-toxic material has the potential to address future environmental and energy concerns. Understanding about the photoinduced interfacial redox events on TiO2 could have profound effect on the degradation of organic pollutants, splitting of H2O into H2 and O2, and selective redox organic transformations. Scientists traditionally accept that for a semiconductor photocatalyst such as TiO2 under the illumination of light with energy larger than its band gap, two photocarriers will be created to carry out their independent reduction and oxidation processes. However, our recent discoveries indicate that it is the concerted rather than independent effect of both photocarriers of valence band hole (hvb(+)) and conduction band electron (ecb(-)) that dictate the product formation during interfacial oxidation event mediated by TiO2 photocatalysis. In this Account, we describe our recent findings on the selective oxidation of organic substrates with O2 mediated by TiO2 photocatalysis. The transfer of O-atoms from O2 to the corresponding products dominates the selective oxidation of alcohols, amines, and alkanes mediated by TiO2 photocatalysis. We ascribe this to the concerted effect of both hvb(+) and ecb(-) of TiO2 in contribution to the oxidation products. These findings imply that O2 plays a unique role in its transfer into the products rather than independent role of ecb(-) scavenger. More importantly, ecb(-) plays a crucial role to ensure the high selectivity for the oxygenation of organic substrates. We can also use the half reactions such as those of the conduction band electron of TiO2 for efficient oxidation reactions with O2. To this end, efficient selective oxidation of organic substrates such as alcohols, amines, and aromatic alkanes with O2 mediated by TiO2 photocatalysis under visible light irradiation has been achieved. In

  4. Selective aerobic oxidation mediated by TiO(2) photocatalysis.

    PubMed

    Lang, Xianjun; Ma, Wanhong; Chen, Chuncheng; Ji, Hongwei; Zhao, Jincai

    2014-02-18

    TiO2 is one of the most studied metal oxide photocatalysts and has unparal-leled efficiency and stability. This cheap, abundant, and non-toxic material has the potential to address future environmental and energy concerns. Understanding about the photoinduced interfacial redox events on TiO2 could have profound effect on the degradation of organic pollutants, splitting of H2O into H2 and O2, and selective redox organic transformations. Scientists traditionally accept that for a semiconductor photocatalyst such as TiO2 under the illumination of light with energy larger than its band gap, two photocarriers will be created to carry out their independent reduction and oxidation processes. However, our recent discoveries indicate that it is the concerted rather than independent effect of both photocarriers of valence band hole (hvb(+)) and conduction band electron (ecb(-)) that dictate the product formation during interfacial oxidation event mediated by TiO2 photocatalysis. In this Account, we describe our recent findings on the selective oxidation of organic substrates with O2 mediated by TiO2 photocatalysis. The transfer of O-atoms from O2 to the corresponding products dominates the selective oxidation of alcohols, amines, and alkanes mediated by TiO2 photocatalysis. We ascribe this to the concerted effect of both hvb(+) and ecb(-) of TiO2 in contribution to the oxidation products. These findings imply that O2 plays a unique role in its transfer into the products rather than independent role of ecb(-) scavenger. More importantly, ecb(-) plays a crucial role to ensure the high selectivity for the oxygenation of organic substrates. We can also use the half reactions such as those of the conduction band electron of TiO2 for efficient oxidation reactions with O2. To this end, efficient selective oxidation of organic substrates such as alcohols, amines, and aromatic alkanes with O2 mediated by TiO2 photocatalysis under visible light irradiation has been achieved. In

  5. Effect of the water-vapor content on the oxidative desulfurization of sulfur-rich coal

    SciTech Connect

    S. Pysh'yev; K. Shevchuk; L. Chmielarz; P. Kutrowski; A. Pattek-Janczyk

    2007-01-15

    Ukrainian sulfur-rich coal containing about 3.6 mass % of sulfur was studied. The desulfurization process was performed in the fluidized-bed reactor in dry (4 vol % of H{sub 2}O vapor) and wet (30-70 vol % of H{sub 2}O vapor) atmospheres in the temperature range of 350-450{sup o}C. A significant influence of the water-vapor content in the reaction mixture on the sulfur removal during the oxidative desulfurization of the coal was observed especially at low temperatures. The extent of FeS{sub 2} oxidation, the main sulfur-containing compound, was studied by Moessbauer spectroscopy. The Moessbauer data revealed different iron-containing products (FeSO{sub 4}nH{sub 2}O, Fe{sub 2}O{sub 3}, Fe{sub 3}O{sub 4}, and Fe{sub 1-x}S) formed in the course of the process carried out in dry and wet atmospheres. The promoting effect of water vapor on the pyrite transformation was observed especially at low temperatures. The mechanism of this promotion on the molecular scale was proposed. 19 refs., 6 figs., 4 tabs.

  6. Near-neutral oxidation of pyrite in coal slurry solids. [Quarterly] technical report, September 1--November 30, 1994

    SciTech Connect

    Frost, J.K.; Dreher, G.B.

    1994-12-31

    In this research project we plan to determine the rate of oxidation of pyrite associated with coaly particles (coal slurry solid) when the pH of the surrounding environment is held at approximately 7.8. Coaly particles that contain pyrite are generated during the preparation of Illinois Basin coal for market. These particles are discharged to an impoundment, which eventually must be reclaimed. The purpose for reclamation is either to prevent the generation of acidic solution as the pyrite in the coal slurry solid reacts with air, or to prevent the migration of the acidic solution to a groundwater aquifer. The reclamation is usually accomplished by covering the impoundment with a four-foot-thick layer of topsoil. One possible alternative method for reclamation of a coal slurry impoundment is to mix in alkaline residue from the fluidized-bed combustion of coal. This codisposal would slow the production of acid and would also neutralize any acid produced. If the codisposal method is found to be environmentally acceptable, it will save the coal mining companies part of their cost of reclamation, and also provide a safe and useful disposal outlet for a portion of the residue that is generated by the fluidized-bed combustion of coal. During this quarter we purchased and set up two automatic titrators, which will be used in determining the rate of pyrite oxidation at nearly neutral pH. The titrators will provide a means for maintaining the pH at the desired level. The rate at which sulfate ion is produced as a result of pyrite oxidation will be used to measure the amount of pyrite oxidized over time.

  7. KINETICS OF DIRECT OXIDATION OF H2S IN COAL GAS TO ELEMENTAL SULFUR

    SciTech Connect

    K.C. Kwon

    2003-01-01

    The direct oxidation of H{sub 2}S to elemental sulfur in the presence of SO{sub 2} is ideally suited for coal gas from commercial gasifiers with a quench system to remove essentially all the trace contaminants except H{sub 2}S. This direct oxidation process has the potential to produce a super clean coal gas more economically than both conventional amine-based processes and HGD/DSRP. The objective of this research is to support the near- and long-term DOE efforts to commercialize this direct oxidation technology. The objectives of this research are to measure kinetics of direct oxidation of H{sub 2}S to elemental sulfur in the presence of a simulated coal gas mixture containing SO{sub 2}, H{sub 2}, and moisture, using 60-{micro}m C-500-04 alumina catalyst particles and a PFA differential fixed-bed micro reactor, and to develop kinetic rate equations and model the direct oxidation process to assist in the design of large-scale plants. To achieve the above-mentioned objectives, experiments on conversion of hydrogen sulfide into elemental sulfur were carried out for the space time range of 0.01-0.047 seconds at 125-155 C to evaluate effects of reaction temperatures, moisture concentrations, reaction pressures on conversion of hydrogen sulfide into elemental sulfur. Simulated coal gas mixtures consist of 61-89 v% hydrogen, 2,300-9,200-ppmv hydrogen sulfide, 1,600-4,900 ppmv sulfur dioxide, and 2.6-13.7 vol % moisture, and nitrogen as remainder. Volumetric feed rates of a simulated coal gas mixture to the reactor are 100-110 cm{sup 3}/min at room temperature and atmospheric pressure (SCCM). The temperature of the reactor is controlled in an oven at 125-155 C. The pressure of the reactor is maintained at 28-127 psia. The following results were obtained based on experimental data generated from the differential reactor system, and their interpretations, (1) Concentration of moisture and concentrations of both H{sub 2}S and SO{sub 2} appear to affect slightly reaction

  8. Selected oxidized fragrance terpenes are common contact allergens.

    PubMed

    Matura, Mihaly; Sköld, Maria; Börje, Anna; Andersen, Klaus E; Bruze, Magnus; Frosch, Peter; Goossens, An; Johansen, Jeanne D; Svedman, Cecilia; White, Ian R; Karlberg, Ann-Therese

    2005-06-01

    Terpenes are widely used fragrance compounds in fine fragrances, but also in domestic and occupational products. Terpenes oxidize easily due to autoxidation on air exposure. Previous studies have shown that limonene, linalool and caryophyllene are not allergenic themselves but readily form allergenic products on air-exposure. This study aimed to determine the frequency and characteristics of allergic reactions to selected oxidized fragrance terpenes other than limonene. In total 1511 consecutive dermatitis patients in 6 European dermatology centres were patch tested with oxidized fragrance terpenes and some oxidation fractions and compounds. Oxidized linalool and its hydroperoxide fraction were found to be common contact allergens. Of the patients tested, 1.3% showed a positive reaction to oxidized linalool and 1.1% to the hydroperoxide fraction. About 0.5% of the patients reacted to oxidized caryophyllene whereas 1 patient reacted to oxidized myrcene. Of the patients reacting to the oxidized terpenes, 58% had fragrance-related contact allergy and/or a positive history for adverse reaction to fragrances. Autoxidation of fragrance terpenes contributes greatly to fragrance allergy, which emphasizes the need of testing with compounds that patients are actually exposed to and not only with the ingredients originally applied in commercial formulations.

  9. Comparative analyses for selected clean coal technologies in the international marketplace

    SciTech Connect

    Szpunar, C.B.; Gillette, J.L.

    1990-07-01

    Clean coal technologies (CCTs) are being demonstrated in research and development programs under public and private sponsorship. Many of these technologies could be marketed internationally. To explore the scope of these international opportunities and to match particular technologies with markets appearing to have high potential, a study was undertaken that focused on seven representative countries: Italy, Japan, Morocco, Turkey, Pakistan, the Peoples' Republic of China, and Poland. The results suggest that there are international markets for CCTs and that these technologies can be cost competitive with more conventional alternatives. The identified markets include construction of new plants and refurbishment of existing ones, especially when decision makers want to decrease dependence on imported oil. This report describes potential international market niches for U.S. CCTs and discusses the status and implications of ongoing CCT demonstration activities. Twelve technologies were selected as representative of technologies under development for use in new or refurbished industrial or electric utility applications. Included are the following: Two generic precombustion technologies: two-stage froth-flotation coal beneficiation and coal-water mixtures (CWMs); Four combustion technologies: slagging combustors, integrated-gasification combined-cycle (IGCC) systems, atmospheric fluidized-bed combustors (AFBCs), and pressurized fluidized-bed combustors (PFBCs); and Six postcombustion technologies: limestone-injection multistage burner (LIMB) systems, gas-reburning sorbent-injection (GRSI) systems, dual-alkali flue-gas desulfurization (FGD), spray-dryer FGD, the NOXSO process, and selective catalytic reduction (SCR) systems. Major chapters of this report have been processed separately for inclusion on the data base.

  10. Selective flotation of fossil resin from Western coal. Final report, July 1, 1990--May 25, 1992

    SciTech Connect

    Jensen, G.F.; Miller, J.D.

    1992-05-25

    The proof-of-concept test program was designed to clarify a number of concerns that have been raised by coal companies who own the valuable resin resource. First, from laboratory bench-scale flotation experiments, a froth product from cleaner flotation containing more than 80% hexane-extractable resin at higher than 80% recovery can be produced. Pilot-plant testing was initiated to demonstrate the selective flotation of fossil resin and to establish a better confidence level in the new technology. Second, pilot-plant testing was designed to evaluate the effect and impact of random variation in slurry solids concentration and feed grade on this new selective fossil resin flotation technology. The flotation performance obtained under these industrial conditions is more realistic for process evaluation. Third, more accurate operating cost data was to be obtained for economic analysis. Fourth, sufficient quantities of the fossil resin concentrate were to be produced from the test program for evaluation by potential industrial users. Fifth, and finally, optimum levels for the operating variables were to be established. Such information was required for eventual scale-up and design of a fossil resin flotation plant. The pilot-plant proof-of-concept testing of selective resinate flotation has demonstrated that: (1) technically, the new flotation technologies discovered at the University of Utah and then improved upon by Advanced Processing Technologies, Inc. provide a highly efficient means to selectively recover fossil resin from coal. The proof-of-concept continuous flotation circuit (about 0.1 tph) resulted in fossil resin recovery with the same separation efficiency as was obtained from laboratory bench-scale testing (more than 80% recovery at about 80% concentrate grade); and (2) economically, the selective flotation process has been shown to be sufficiently profitable to justify the development of a fossil resin industry based on this new flotation process.

  11. Porcelain enamelled absorbers, coated by spectral selective tin oxide

    SciTech Connect

    Simonis, F.; Faber, A.J.; Hoogendoorn, C.J.

    1987-02-01

    The use of porcelain enamelled absorbers in flat plate collectors features longevity thanks to the durability and thermal stability of the enamel finish. The porcelain enamel can be made spectral selective by coating with doped tin oxide or indium oxide. The application procedure involves an enamelling step followed by a pyrosol process with tin or indium compounds. The optical properties of tin oxide coated enamel yield values of 0.90-0.92 absorptance and 0.13-0.18 hemispherical emittance. The temperature dependence of the emittance is very small. The thermal stability has been proved up to 400/sup 0/C in air.

  12. The effect of emission from coal combustion in nonindustrial sources on deposition of sulfur and oxidized nitrogen in Poland.

    PubMed

    Kryza, Maciej; Werner, Małgorzata; Błaś, Marek; Dore, Anthony J; Sobik, Mieczysław

    2010-07-01

    Poland has one of the largest sulfur and nitrogen emissions in Europe. This is mainly because coal is a main fuel in industrial and nonindustrial combustion. The aim of this paper is to assess the amount of sulfur and nitrogen deposited from SNAP sector 02 (nonindustrial sources) coal combustion. To assess this issue, the Fine Resolution Atmospheric Multipollutant Exchange (FRAME) model was used. The results suggest that industrial combustion has the largest impact on deposition of oxidized sulfur, whereas the oxidized nitrogen national deposition budget is dominated by transboundary transport. The total mass of pollutants deposited in Poland, originating from nonindustrial coal combustion, is 45 Gg of sulfur and 2.5 Gg of nitrogen, which is over 18% of oxidized sulfur and nearly 2% of oxidized nitrogen deposited. SNAP 02 is responsible for up to 80% of dry-deposited sulfur and 11% of nitrogen. The contribution to wet deposition is largest in central Poland in the case of sulfur and in some areas can exceed 11%. For oxidized nitrogen, nonindustrial emissions contribute less than 1% over the whole area of Poland. The switch from coal to gas fuel in this sector will result in benefits in sulfur and nitrogen deposition reduction.

  13. The effect of emission from coal combustion in nonindustrial sources on deposition of sulfur and oxidized nitrogen in Poland.

    PubMed

    Kryza, Maciej; Werner, Małgorzata; Błaś, Marek; Dore, Anthony J; Sobik, Mieczysław

    2010-07-01

    Poland has one of the largest sulfur and nitrogen emissions in Europe. This is mainly because coal is a main fuel in industrial and nonindustrial combustion. The aim of this paper is to assess the amount of sulfur and nitrogen deposited from SNAP sector 02 (nonindustrial sources) coal combustion. To assess this issue, the Fine Resolution Atmospheric Multipollutant Exchange (FRAME) model was used. The results suggest that industrial combustion has the largest impact on deposition of oxidized sulfur, whereas the oxidized nitrogen national deposition budget is dominated by transboundary transport. The total mass of pollutants deposited in Poland, originating from nonindustrial coal combustion, is 45 Gg of sulfur and 2.5 Gg of nitrogen, which is over 18% of oxidized sulfur and nearly 2% of oxidized nitrogen deposited. SNAP 02 is responsible for up to 80% of dry-deposited sulfur and 11% of nitrogen. The contribution to wet deposition is largest in central Poland in the case of sulfur and in some areas can exceed 11%. For oxidized nitrogen, nonindustrial emissions contribute less than 1% over the whole area of Poland. The switch from coal to gas fuel in this sector will result in benefits in sulfur and nitrogen deposition reduction. PMID:20681433

  14. Selective placement of carbon nanotubes on metal-oxide surfaces.

    PubMed

    Hannon, J B; Afzali, A; Klinke, Ch; Avouris, Ph

    2005-09-13

    We describe a method to selectively position carbon nanotubes on Al2O3 and HfO2 surfaces. The method exploits the selective binding of alkylphosphonic acids to oxide surfaces with large isoelectric points (i.e. basic rather than acidic surfaces). We have patterned oxide surfaces with acids using both microcontact printing and conventional lithography. With proper choice of the functional end group (e.g., -CH3 or -NH2), nanotube adhesion to the surface can be either prevented or enhanced.

  15. Method and apparatus for the selective separation of gaseous coal gasification products by pressure swing adsorption

    DOEpatents

    Ghate, Madhav R.; Yang, Ralph T.

    1987-01-01

    Bulk separation of the gaseous components of multi-component gases provided by the gasification of coal including hydrogen, carbon monoxide, methane, and acid gases (carbon dioxide plus hydrogen sulfide) are selectively adsorbed by a pressure swing adsorption technique using activated carbon, zeolite or a combination thereof as the adsorbent. By charging a column containing the adsorbent with a gas mixture and pressurizing the column to a pressure sufficient to cause the adsorption of the gases and then reducing the partial pressure of the contents of the column, the gases are selectively and sequentially desorbed. Hydrogen, the least absorbable gas of the gaseous mixture, is the first gas to be desorbed and is removed from the column in a co-current direction followed by the carbon monoxide, hydrogen and methane. With the pressure in the column reduced to about atmospheric pressure the column is evacuated in a countercurrent direction to remove the acid gases from the column. The present invention is particularly advantageous as a producer of high parity hydrogen from gaseous products of coal gasification and as an acid gas scrubber.

  16. Method and apparatus for the selective separation of gaseous coal gasification products by pressure swing adsorption

    DOEpatents

    Ghate, M.R.; Yang, R.T.

    1985-10-03

    Bulk separation of the gaseous components of multi-component gases provided by the gasification of coal including hydrogen, carbon monoxide, methane, and acid gases (carbon dioxide plus hydrogen sulfide) are selectively adsorbed by a pressure swing adsorption technique using activated carbon zeolite or a combination thereof as the adsorbent. By charging a column containing the adsorbent with a gas mixture and pressurizing the column to a pressure sufficient to cause the adsorption of the gases and then reducing the partial pressure of the contents of the column, the gases are selectively and sequentially desorbed. Hydrogen, the least absorbable gas of the gaseous mixture, is the first gas to be desorbed and is removed from the column in a co-current direction followed by the carbon monoxide, hydrogen and methane. With the pressure in the column reduced to about atmospheric pressure the column is evacuated in a countercurrent direction to remove the acid gases from the column. The present invention is particularly advantageous as a producer of high purity hydrogen from gaseous products of coal gasification and as an acid gas scrubber. 2 figs., 2 tabs.

  17. Full scale calcium bromide injection with subsequent mercury oxidation and removal within wet flue gas desulphurization system: Experience at a 700 MW coal-fired power facility

    NASA Astrophysics Data System (ADS)

    Berry, Mark Simpson

    The Environmental Protection Agency promulgated the Mercury and Air Toxics Standards rule, which requires that existing power plants reduce mercury emissions to meet an emission rate of 1.2 lb/TBtu on a 30-day rolling average and that new plants meet a 0.0002 lb/GWHr emission rate. This translates to mercury removals greater than 90% for existing units and greater than 99% for new units. Current state-of-the-art technology for the control of mercury emissions uses activated carbon injected upstream of a fabric filter, a costly proposition. For example, a fabric filter, if not already available, would require a 200M capital investment for a 700 MW size unit. A lower-cost option involves the injection of activated carbon into an existing cold-side electrostatic precipitator. Both options would incur the cost of activated carbon, upwards of 3M per year. The combination of selective catalytic reduction (SCR) reactors and wet flue gas desulphurization (wet FGD) systems have demonstrated the ability to substantially reduce mercury emissions, especially at units that burn coals containing sufficient halogens. Halogens are necessary for transforming elemental mercury to oxidized mercury, which is water-soluble. Plants burning halogen-deficient coals such as Power River Basin (PRB) coals currently have no alternative but to install activated carbon-based approaches to control mercury emissions. This research consisted of investigating calcium bromide addition onto PRB coal as a method of increasing flue gas halogen concentration. The treated coal was combusted in a 700 MW boiler and the subsequent treated flue gas was introduced into a wet FGD. Short-term parametric and an 83-day longer-term tests were completed to determine the ability of calcium bromine to oxidize mercury and to study the removal of the mercury in a wet FGD. The research goal was to show that calcium bromine addition to PRB coal was a viable approach for meeting the Mercury and Air Toxics Standards rule

  18. Study of enhanced low-quality coal oxidative desulphurization and deashing by using HNO3 and microwave pretreatment.

    PubMed

    Ma, Xiangmei; Zhang, Mingxu; Min, Fanfei

    2014-01-01

    In this paper, the effect of urea-hydrogen peroxide (UHP) solution on desulphurization and demineralization of coal with high sulphur and high ash by using HNO3 and microwave pretreatment was investigated. The oxidation process is strongly dependent on irradiation power and time for microwave pretreatment, UHP concentration, leaching time and temperature of the UHP solution. X-ray diffraction and Fourier transform infrared technique have been performed for the raw and treated coals. Compared with the UHP alone, successive treatments with HNO3 and microwave pretreatment resulted in the significant removal of total sulphur and mineral matter from the coal. The proposed experimental method has the meaning of practical guide to the desulphurization and deashing of coal by microwave.

  19. Studies of incipient oxidation of coal-pyrite for improved pyrite rejection

    SciTech Connect

    Yoon, R.H.; Richardson, P.E.

    1992-01-01

    In order to foster the development of advanced coal cleaning technologies fundamental studies.of the initial stages of pyrite oxidation have been.initiated. This work is being done on pyrite surfaces that are freshly fractured in an electrolyte solution. This procedure produces surfaces that are initially unoxidized, allowing the subsequent oxidation processes to be studied in detail. It is shown that freshly fractured pyrite electrodes instantaneously (at fracture) assume a rest potential several hundred millivolts more negative than the usual open-circuit potential. A finite, anodic photocurrent, is also observed on the fractured electrodes. Following cleavage, the rest potential increases, indicating an oxidation reaction occurring on the electrodes. The photocurrent is relatively insensitive to this oxidation process, and to moderate anodic and cathodic polarization. However, strong cathodic polarization to about -0.76 V (SHE) at pH 9.2 causes the photocurrent to decrease to zero. No reversal in the sign of the photocurrent is observed and it is believed that the flat band potential occurs near -0.76 V, i.e., where the photocurrent goes to zero. Voltammetry indicates that pyrite also undergoes cathodic decomposition at -0.76 V. This establishes that pyrite must be cathodically decomposed to reach the flat band potential.

  20. Charge transport-driven selective oxidation of graphene

    NASA Astrophysics Data System (ADS)

    Lee, Young Keun; Choi, Hongkyw; Lee, Changhwan; Lee, Hyunsoo; Goddeti, Kalyan C.; Moon, Song Yi; Doh, Won Hui; Baik, Jaeyoon; Kim, Jin-Soo; Choi, Jin Sik; Choi, Choon-Gi; Park, Jeong Young

    2016-06-01

    Due to the tunability of the physical, electrical, and optical characteristics of graphene, precisely controlling graphene oxidation is of great importance for potential applications of graphene-based electronics. Here, we demonstrate a facile and precise way for graphene oxidation controlled by photoexcited charge transfer depending on the substrate and bias voltage. It is observed that graphene on TiO2 is easily oxidized under UV-ozone treatment, while graphene on SiO2 remains unchanged. The mechanism for the selective oxidation of graphene on TiO2 is associated with charge transfer from the TiO2 to the graphene. Raman spectra were used to investigate the graphene following applied bias voltages on the graphene/TiO2 diode under UV-ozone exposure. We found that under a reverse bias of 0.6 V on the graphene/TiO2 diode, graphene oxidation was accelerated under UV-ozone exposure, thus confirming the role of charge transfer between the graphene and the TiO2 that results in the selective oxidation of the graphene. The selective oxidation of graphene can be utilized for the precise, nanoscale patterning of the graphene oxide and locally patterned chemical doping, finally leading to the feasibility and expansion of a variety of graphene-based applications.Due to the tunability of the physical, electrical, and optical characteristics of graphene, precisely controlling graphene oxidation is of great importance for potential applications of graphene-based electronics. Here, we demonstrate a facile and precise way for graphene oxidation controlled by photoexcited charge transfer depending on the substrate and bias voltage. It is observed that graphene on TiO2 is easily oxidized under UV-ozone treatment, while graphene on SiO2 remains unchanged. The mechanism for the selective oxidation of graphene on TiO2 is associated with charge transfer from the TiO2 to the graphene. Raman spectra were used to investigate the graphene following applied bias voltages on the graphene/TiO2

  1. Protocols for the selective cleavage of carbon-sulfur bonds in coal. Quarterly report, September 1, 1991--November 30, 1991

    SciTech Connect

    Bausch, M.

    1991-12-31

    Removal of the organic sulfur in coal constitutes one of the major challenges facing fossil fuel scientists today. A cost--effective of desulfurizing Illinois coal is non-existent at the present time. Research in our group aims to develop a simple protocol for sulfur removal by gaining understanding of how various additives can enhance the rates of C-S bond cleavage in Illinois coal and coal model compounds, relative to fragmentation of the coal macromolecule via C-C, C-O, and C-N bond cleavage. During this funding period, we plan to carry out examinations of: (a) the effects of various reaction conditions on radical-initiated and Lewis acid-catalyzed C-S bond cleavages; (b) the effects of caustic impregnation and subsequent alcoholic reflux on C-S bond cleavage strategies; (c) the reactions of coal model compounds with electron-deficient substrates; (d) examinations of photooxidative C-S bond cleavage reactions; (e) the effects of moderate (300--400{degrees}C) temperatures and pressures as well as ultrasonic radiation on (a) - (c). Also planned are differential scanning calorimetric (DSC) examinations of selected C-S bond cleavage protocols, including those on Illinois coals that possess varying amounts of organic and inorganic sulfur.

  2. Resource requirements and economics of the coal-mining process: a comparative analysis of mines in selected countries

    SciTech Connect

    Astakhov, A.; Gruebler, A.

    1984-06-01

    This report examines the natural resource requirements and economics of the resource extraction process, taking coal-mining activities as an example. Coal was chosen for the study because it is receiving growing attention as the fossile energy resource with the largest potential to contribute to the world's long-term energy supply. The computerized description of the extraction process is stored in the Coal Mines Data Base (CMDB) which was developed within the framework of this study. The data base currently holds information on 70 mines located in different countries. The analytic approach used is the first of its kind to compare resource requirements and economics of coal mines under such a broad range of geological and socioeconomic conditions. A general model of the factors influencing resource inputs and impacts of the coal-mining process is presented. Then for each of the main mining methods (opencast, conventional underground, and hydraulic underground) the principal geological and technological factors influencing the resource requirements, economics, and environmental impacts, as well as the comparative advantages and disadvantages of each mining method, are discussed. For the three main mining methods the resource requirements (including manpower, energy, materials, and land) and the economics (including construction investments and operating costs) are then quantified and their cost structures (i.e. requirements for the different operations at a mine) are examined in detail using data from coal mines in the USA, the USSR, and other selected coal-producing countries (Australia, Austria, and France).

  3. Characterization of Manganese Oxide Precipitates from Appalachian Coal Mine Mine Drainage Treatment Systems

    SciTech Connect

    Tan, H.; Zhang, G; Heaney, P; Webb, S; Burgos, W

    2010-01-01

    The removal of Mn(II) from coal mine drainage (CMD) by chemical addition/active treatment can significantly increase treatment costs. Passive treatment for Mn removal involves promotion of biological oxidative precipitation of manganese oxides (MnO{sub x}). Manganese(II) removal was studied in three passive treatment systems in western Pennsylvania that differed based on their influent Mn(II) concentrations (20-150 mg/L), system construction ({+-}inoculation with patented Mn(II)-oxidizing bacteria), and bed materials (limestone vs. sandstone). Manganese(II) removal occurred at pH values as low as 5.0 and temperatures as low as 2 C, but was enhanced at circumneutral pH and warmer temperatures. Trace metals such as Zn, Ni and Co were removed effectively, in most cases preferentially, into the MnO{sub x} precipitates. Based on synchrotron radiation X-ray diffraction and Mn K-edge extended X-ray absorption fine structure spectroscopy, the predominant Mn oxides at all sites were poorly crystalline hexagonal birnessite, triclinic birnessite and todorokite. The surface morphology of the MnOx precipitates from all sites was coarse and 'sponge-like' composed of nm-sized lathes and thin sheets. Based on scanning electron microscopy (SEM), MnO{sub x} precipitates were found in close proximity to both prokaryotic and eukaryotic organisms. The greatest removal efficiency of Mn(II) occurred at the one site with a higher pH in the bed and a higher influent total organic C (TOC) concentration (provided by an upstream wetland). Biological oxidation of Mn(II) driven by heterotrophic activity was most likely the predominant Mn removal mechanism in these systems. Influent water chemistry and Mn(II) oxidation kinetics affected the relative distribution of MnOx mineral assemblages in CMD treatment systems.

  4. Selective electrochemical generation of hydrogen peroxide from water oxidation

    DOE PAGES

    Viswanathan, Venkatasubramanian; Hansen, Heine A.; Norskov, Jens K.

    2015-10-08

    Water is a life-giving source, fundamental to human existence, yet over a billion people lack access to clean drinking water. The present techniques for water treatment such as piped, treated water rely on time and resource intensive centralized solutions. In this work, we propose a decentralized device concept that can utilize sunlight to split water into hydrogen and hydrogen peroxide. The hydrogen peroxide can oxidize organics while the hydrogen bubbles out. In enabling this device, we require an electrocatalyst that can oxidize water while suppressing the thermodynamically favored oxygen evolution and form hydrogen peroxide. Using density functional theory calculations, wemore » show that the free energy of adsorbed OH* can be used to determine selectivity trends between the 2e– water oxidation to H2O2 and the 4e– oxidation to O2. We show that materials which bind oxygen intermediates sufficiently weakly, such as SnO2, can activate hydrogen peroxide evolution. Furthermore, we present a rational design principle for the selectivity in electrochemical water oxidation and identify new material candidates that could perform H2O2 evolution selectively.« less

  5. Selective electrochemical generation of hydrogen peroxide from water oxidation

    SciTech Connect

    Viswanathan, Venkatasubramanian; Hansen, Heine A.; Norskov, Jens K.

    2015-10-08

    Water is a life-giving source, fundamental to human existence, yet over a billion people lack access to clean drinking water. The present techniques for water treatment such as piped, treated water rely on time and resource intensive centralized solutions. In this work, we propose a decentralized device concept that can utilize sunlight to split water into hydrogen and hydrogen peroxide. The hydrogen peroxide can oxidize organics while the hydrogen bubbles out. In enabling this device, we require an electrocatalyst that can oxidize water while suppressing the thermodynamically favored oxygen evolution and form hydrogen peroxide. Using density functional theory calculations, we show that the free energy of adsorbed OH* can be used to determine selectivity trends between the 2e– water oxidation to H2O2 and the 4e– oxidation to O2. We show that materials which bind oxygen intermediates sufficiently weakly, such as SnO2, can activate hydrogen peroxide evolution. Furthermore, we present a rational design principle for the selectivity in electrochemical water oxidation and identify new material candidates that could perform H2O2 evolution selectively.

  6. Selective Electrochemical Generation of Hydrogen Peroxide from Water Oxidation.

    PubMed

    Viswanathan, Venkatasubramanian; Hansen, Heine A; Nørskov, Jens K

    2015-11-01

    Water is a life-giving source, fundamental to human existence, yet over a billion people lack access to clean drinking water. The present techniques for water treatment such as piped, treated water rely on time and resource intensive centralized solutions. In this work, we propose a decentralized device concept that can utilize sunlight to split water into hydrogen and hydrogen peroxide. The hydrogen peroxide can oxidize organics while the hydrogen bubbles out. In enabling this device, we require an electrocatalyst that can oxidize water while suppressing the thermodynamically favored oxygen evolution and form hydrogen peroxide. Using density functional theory calculations, we show that the free energy of adsorbed OH* can be used to determine selectivity trends between the 2e(-) water oxidation to H2O2 and the 4e(-) oxidation to O2. We show that materials which bind oxygen intermediates sufficiently weakly, such as SnO2, can activate hydrogen peroxide evolution. We present a rational design principle for the selectivity in electrochemical water oxidation and identify new material candidates that could perform H2O2 evolution selectively.

  7. 1999 resource assessment of selected Tertiary coal beds and zones in the Northern Rocky Mountains and Great Plains region

    USGS Publications Warehouse

    ,

    1999-01-01

    The USGS has assessed resources of selected coal of the Fort Union Formation and equivalent units in the Northern Rocky Mountains and Great Plains region. The assessment focused on coal in the Powder River, Williston, Hanna-Carbon, and Greater Green River basins most likely to be utilized in the next few decades. In other basins in the region Tertiary coal resources are summarized but not assessed. Disc 1, in PDF files, includes results of the assessment and chapters on coal geology, quantity and quality, and land use and ownership. Disc 2 provides GIS files for land use and ownership maps and geologic maps, and basic GIS data for the assessed basins. ArcView shapefiles, PDF files for cross sections and TIFF files are included along with ArcView Datapublisher software for Windows-based computer systems.

  8. Greenhouse gas emissions from Australian open-cut coal mines: contribution from spontaneous combustion and low-temperature oxidation.

    PubMed

    Day, Stuart J; Carras, John N; Fry, Robyn; Williams, David J

    2010-07-01

    Spontaneous combustion and low-temperature oxidation of waste coal and other carbonaceous material at open-cut coal mines are potentially significant sources of greenhouse gas emissions. However, the magnitude of these emissions is largely unknown. In this study, emissions from spontaneous combustion and low-temperature oxidation were estimated for six Australian open-cut coal mines with annual coal production ranging from 1.7 to more than 16 Mt. Greenhouse emissions from all other sources at these mines were also estimated and compared to those from spontaneous combustion and low-temperature oxidation. In all cases, fugitive emission of methane was the largest source of greenhouse gas; however, in some mines, spontaneous combustion accounted for almost a third of all emissions. For one mine, it was estimated that emissions from spontaneous combustion were around 250,000 t CO(2)-e per annum. The contribution from low-temperature oxidation was generally less than about 1% of the total for all six mines. Estimating areas of spoil affected by spontaneous combustion by ground-based surveys was prone to under-report the area. Airborne infrared imaging appears to be a more reliable method.

  9. Shape-selective sieving layers on an oxide catalyst surface.

    PubMed

    Canlas, Christian P; Lu, Junling; Ray, Natalie A; Grosso-Giordano, Nicolas A; Lee, Sungsik; Elam, Jeffrey W; Winans, Randall E; Van Duyne, Richard P; Stair, Peter C; Notestein, Justin M

    2012-12-01

    New porous materials such as zeolites, metal-organic frameworks and mesostructured oxides are of immense practical utility for gas storage, separations and heterogeneous catalysis. Their extended pore structures enable selective uptake of molecules or can modify the product selectivity (regioselectivity or enantioselectivity) of catalyst sites contained within. However, diffusion within pores can be problematic for biomass and fine chemicals, and not all catalyst classes can be readily synthesized with pores of the correct dimensions. Here, we present a novel approach that adds reactant selectivity to existing, non-porous oxide catalysts by first grafting the catalyst particles with single-molecule sacrificial templates, then partially overcoating the catalyst with a second oxide through atomic layer deposition. This technique is used to create sieving layers of Al(2)O(3) (thickness, 0.4-0.7 nm) with 'nanocavities' (<2 nm in diameter) on a TiO(2) photocatalyst. The additional layers result in selectivity (up to 9:1) towards less hindered reactants in otherwise unselective, competitive photocatalytic oxidations and transfer hydrogenations. PMID:23174984

  10. Shape-selective sieving layers on an oxide catalyst surface

    NASA Astrophysics Data System (ADS)

    Canlas, Christian P.; Lu, Junling; Ray, Natalie A.; Grosso-Giordano, Nicolas A.; Lee, Sungsik; Elam, Jeffrey W.; Winans, Randall E.; van Duyne, Richard P.; Stair, Peter C.; Notestein, Justin M.

    2012-12-01

    New porous materials such as zeolites, metal-organic frameworks and mesostructured oxides are of immense practical utility for gas storage, separations and heterogeneous catalysis. Their extended pore structures enable selective uptake of molecules or can modify the product selectivity (regioselectivity or enantioselectivity) of catalyst sites contained within. However, diffusion within pores can be problematic for biomass and fine chemicals, and not all catalyst classes can be readily synthesized with pores of the correct dimensions. Here, we present a novel approach that adds reactant selectivity to existing, non-porous oxide catalysts by first grafting the catalyst particles with single-molecule sacrificial templates, then partially overcoating the catalyst with a second oxide through atomic layer deposition. This technique is used to create sieving layers of Al2O3 (thickness, 0.4-0.7 nm) with ‘nanocavities’ (<2 nm in diameter) on a TiO2 photocatalyst. The additional layers result in selectivity (up to 9:1) towards less hindered reactants in otherwise unselective, competitive photocatalytic oxidations and transfer hydrogenations.

  11. Selective electrocatalytic oxidation of sorbitol to fructose and sorbose.

    PubMed

    Kwon, Youngkook; de Jong, Ed; van der Waal, Jan Kees; Koper, Marc T M

    2015-03-01

    A new electrocatalytic method for the selective electrochemical oxidation of sorbitol to fructose and sorbose is demonstrated by using a platinum electrode promoted by p-block metal atoms. By the studying a range of C4, C5 and C6 polyols, it is found that the promoter interferes with the stereochemistry of the polyol and thereby modifies its reactivity.

  12. Progressive oxidation of pyrite in five bituminous coal samples: An As XANES and 57Fe Mössbauer spectroscopic study

    USGS Publications Warehouse

    Kolker, Allan; Huggins, Frank E.

    2007-01-01

    Naturally occurring pyrite commonly contains minor substituted metals and metalloids (As, Se, Hg, Cu, Ni, etc.) that can be released to the environment as a result of its weathering. Arsenic, often the most abundant minor constituent in pyrite, is a sensitive monitor of progressive pyrite oxidation in coal. To test the effect of pyrite composition and environmental parameters on the rate and extent of pyrite oxidation in coal, splits of five bituminous coal samples having differing amounts of pyrite and extents of As substitution in the pyrite, were exposed to a range of simulated weathering conditions over a period of 17 months. Samples investigated include a Springfield coal from Indiana (whole coal pyritic S = 2.13 wt.%; As in pyrite = detection limit (d.l.) to 0.06 wt.%), two Pittsburgh coal samples from West Virginia (pyritic S = 1.32–1.58 wt.%; As in pyrite = d.l. to 0.34 wt.%), and two samples from the Warrior Basin, Alabama (pyritic S = 0.26–0.27 wt.%; As in pyrite = d.l. to 2.72 wt.%). Samples were collected from active mine faces, and expected differences in the concentration of As in pyrite were confirmed by electron microprobe analysis. Experimental weathering conditions in test chambers were maintained as follows: (1) dry Ar atmosphere; (2) dry O2 atmosphere; (3) room atmosphere (relative humidity ∼20–60%); and (4) room atmosphere with samples wetted periodically with double-distilled water. Sample splits were removed after one month, nine months, and 17 months to monitor the extent of As and Fe oxidation using As X-ray absorption near-edge structure (XANES) spectroscopy and 57Fe Mössbauer spectroscopy, respectively. Arsenic XANES spectroscopy shows progressive oxidation of pyritic As to arsenate, with wetted samples showing the most rapid oxidation. 57Fe Mössbauer spectroscopy also shows a much greater proportion of Fe3+ forms (jarosite, Fe3+ sulfate, FeOOH) for samples stored under wet conditions, but much less

  13. Heat removal from high temperature tubular solid oxide fuel cells utilizing product gas from coal gasifiers.

    SciTech Connect

    Parkinson, W. J. ,

    2003-01-01

    In this work we describe the results of a computer study used to investigate the practicality of several heat exchanger configurations that could be used to extract heat from tubular solid oxide fuel cells (SOFCs) . Two SOFC feed gas compositions were used in this study. They represent product gases from two different coal gasifier designs from the Zero Emission Coal study at Los Alamos National Laboratory . Both plant designs rely on the efficient use of the heat produced by the SOFCs . Both feed streams are relatively rich in hydrogen with a very small hydrocarbon content . One feed stream has a significant carbon monoxide content with a bit less hydrogen . Since neither stream has a significant hydrocarbon content, the common use of the endothermic reforming reaction to reduce the process heat is not possible for these feed streams . The process, the method, the computer code, and the results are presented as well as a discussion of the pros and cons of each configuration for each process .

  14. Reduction of Nitrogen Oxides Emissions from a Coal-Fired Boiler Unit

    NASA Astrophysics Data System (ADS)

    Zhuikov, Andrey V.; Feoktistov, Dmitry V.; Koshurnikova, Natalya N.; Zlenko, Lyudmila V.

    2016-02-01

    During combustion of fossil fuels a large amount of harmful substances are discharged into the atmospheres of cities by industrial heating boiler houses. The most harmful substances among them are nitrogen oxides. The paper presents one of the most effective technological solutions for suppressing nitrogen oxides; it is arrangement of circulation process with additional mounting of the nozzle directed into the bottom of the ash hopper. When brown high-moisture coals are burnt in the medium power boilers, generally fuel nitrogen oxides are produced. It is possible to reduce their production by two ways: lowering the temperature in the core of the torch or decreasing the excess-air factor in the boiler furnace. Proposed solution includes the arrangement of burning process with additional nozzle installed in the lower part of the ash hopper. Air supply from these nozzles creates vortex involving large unburned fuel particles in multiple circulations. Thereby time of their staying in the combustion zone is prolonging. The findings describe the results of the proposed solution; and recommendations for the use of this technological method are given for other boilers.

  15. Combustion process and nitrogen oxides emission of Shenmu coal added with sodium acetate

    SciTech Connect

    Yang Weijuan; Zhou Junhu; Liu Maosheng; Zhou Zhijun; Liu Jianzhong; Cen Kefa

    2007-09-15

    Shenmu bituminous coal with 4% sodium acetate added was used to investigate the characteristics of combustion and nitrogen oxide (NOx) release in a fixed bed reactor heated by a tube furnace. The composition of the flue gas was analyzed to investigate the effects of sodium acetate on the combustion process and NOx emission. The experiments were carried out in a partial reductive atmosphere and a strong oxidative atmosphere. The O{sub 2} valley value in the partial reductive atmosphere was reduced by the added sodium acetate. Sodium acetate accelerated the combustion and shortened the combustion process. The experimental results showed that the emissions of NO, NO{sub 2}, and N{sub 2}O were affected by the reacting atmosphere and the combustion temperature. In the strong oxidative atmosphere, sodium acetate resulted in a slight NOx reduction. In the partial reductive atmosphere, sodium acetate reduced both the peak value of NO concentration and the total NO emission significantly. An over 30% NOx reduction efficiency was achieved at 900{sup o}C in the partial reductive atmosphere, which decreased with the increase in temperature. Sodium acetate was decomposed into hydrocarbon radicals and sodium hydroxide, which can both reduce NOx emissions due to their special reactions with the nitrogen component. 17 refs., 11 figs., 2 tabs.

  16. Multiple sample characterization of coals and other substances by controlled-atmosphere programmed temperature oxidation

    DOEpatents

    LaCount, Robert B.

    1993-01-01

    A furnace with two hot zones holds multiple analysis tubes. Each tube has a separable sample-packing section positioned in the first hot zone and a catalyst-packing section positioned in the second hot zone. A mass flow controller is connected to an inlet of each sample tube, and gas is supplied to the mass flow controller. Oxygen is supplied through a mass flow controller to each tube to either or both of an inlet of the first tube and an intermediate portion between the tube sections to intermingle with and oxidize the entrained gases evolved from the sample. Oxidation of those gases is completed in the catalyst in each second tube section. A thermocouple within a sample reduces furnace temperature when an exothermic condition is sensed within the sample. Oxidized gases flow from outlets of the tubes to individual gas cells. The cells are sequentially aligned with an infrared detector, which senses the composition and quantities of the gas components. Each elongated cell is tapered inward toward the center from cell windows at the ends. Volume is reduced from a conventional cell, while permitting maximum interaction of gas with the light beam. Reduced volume and angulation of the cell inlets provide rapid purgings of the cell, providing shorter cycles between detections. For coal and other high molecular weight samples, from 50% to 100% oxygen is introduced to the tubes.

  17. Small-Scale Coal-Biomass to Liquids Production Using Highly Selective Fischer-Tropsch Synthesis

    SciTech Connect

    Gangwal, Santosh K.; McCabe, Kevin

    2015-04-30

    The research project advanced coal-to-liquids (CTL) and coal-biomass to liquids (CBTL) processes by testing and validating Chevron’s highly selective and active cobalt-zeolite hybrid Fischer-Tropsch (FT) catalyst to convert gasifier syngas predominantly to gasoline, jet fuel and diesel range hydrocarbon liquids, thereby eliminating expensive wax upgrading operations The National Carbon Capture Center (NCCC) operated by Southern Company (SC) at Wilsonville, Alabama served as the host site for the gasifier slip-stream testing/demonstration. Southern Research designed, installed and commissioned a bench scale skid mounted FT reactor system (SR-CBTL test rig) that was fully integrated with a slip stream from SC/NCCC’s transport integrated gasifier (TRIGTM). The test-rig was designed to receive up to 5 lb/h raw syngas augmented with bottled syngas to adjust the H2/CO molar ratio to 2, clean it to cobalt FT catalyst specifications, and produce liquid FT products at the design capacity of 2 to 4 L/day. It employed a 2-inch diameter boiling water jacketed fixed-bed heat-exchange FT reactor incorporating Chevron’s catalyst in Intramicron’s high thermal conductivity micro-fibrous entrapped catalyst (MFEC) packing to efficiently remove heat produced by the highly exothermic FT reaction.

  18. Indexes of hydrologic data from selected coal-mining areas in northwestern Colorado

    USGS Publications Warehouse

    Gaggiani, N.G.

    1989-01-01

    Currently (1988), data from hydrologic studies related to coal mining that have been done in northwestern Colorado since the early 1970 's are stored in the files of private companies and government offices and in various computer systems. To compile these data for additional research, a trip to each office would have to be made to determine the availability and acceptability of the data. The U.S. Geological Survey, in cooperation with the U.S. Bureau of Land Management and the Colorado Mined Land Reclamation Division, has created a database (COALDATA) that includes stream discharge, groundwater levels, and chemical analysis of water samples that were collected by private companies and government agencies other than the U.S. Geological Survey in and near selected coal mines in northwestern Colorado. Indexes in this report list 93 surface water sites and 95 groundwater sites where hydrologic data are available in the COALDATA data base. The indexes also list 62 surface water sites and 480 groundwater sites in the U.S. Geological Survey data base, which is separate from the COALDATA data base and contains only data collected by the U.S. Geological Survey. The combined output of the COALDATA data base and the U.S. Geological Survey data base provides surface water and groundwater data that include most of the study area. (USGS)

  19. Ruthenium ion-catalyzed oxidation of Shenfu coal and its residues

    SciTech Connect

    Yao-Guo Huang; Zhi-Min Zong; Zi-Shuo Yao; Yu-Xuan Zheng; Jie Mou; Guang-Feng Liu; Jin-Pei Cao; Ming-Jie Ding; Ke-Ying Cai; Feng Wang; Wei Zhao; Zhi-Lin Xia; Lin Wu; Xian-Yong Wei

    2008-05-15

    Shenfu coal (SFC), its liquefaction residue (RL), and carbon disulfide (CS{sub 2})/tetrahydrofuran (THF)-inextractable matter (RE) were subject to ruthenium ion-catalyzed oxidation to understand the differences in structural features among the above three samples. The results suggest that SFC is rich in long-chain arylalkanes and {alpha}. {omega}-diarylalkanes (DAAs) with carbon number of methylene linkage from 2 to 4 and that long-chain arylalkanes and DAAs are reactive toward hydroliquefaction and soluble in a CS{sub 2}/THF mixed solvent, whereas highly condensed aromatic species in SFC show poor solubility in the CS{sub 2}/THF mixed solvent. 29 refs., 6 figs., 4 tabs.

  20. Characterization and evaluation of washability of Alaskan coals: Fifty selected seams from various coal fields: Final technical report, September 30, 1976-February 28, 1986. [50 coal seams

    SciTech Connect

    Rao, P.D.

    1986-09-01

    This final report is the result of a study initiated in 1976 to obtain washability data for Alaskan coals, to supplement the efforts of the US Department of Energy in their ongoing studies on washability of US coals. Washability characteristics were determined for fifty coal samples from the Northern Alaska, Chicago Creek, Unalakleet, Nenana, Matanuska, Beluga, Yentna and Herendeen Bay coal fields. The raw coal was crushed to 1-1/2 inches, 3/8 inch, 14 mesh and 65 mesh top sizes, and float-sink separations were made at 1.30, 1.40 and 1.60 specific gravities. A limited number of samples were also crushed to 200 and 325 mesh sizes prior to float-sink testing. Samples crushed to 65 mesh top size were also separated at 1.60 specific gravity and the float and sink products were characterized for proximate and ultimate analyses, ash composition and ash fusibility. 72 refs., 79 figs., 57 tabs.

  1. Partitioning of selected trace elements in coal combustion products from two coal-burning power plants in the United States

    USGS Publications Warehouse

    Swanson, Sharon M.; Engle, Mark A.; Ruppert, Leslie F.; Affolter, Ronald H.; Jones, Kevin B.

    2013-01-01

    Samples of feed coal (FC), bottom ash (BA), economizer fly ash (EFA), and fly ash (FA) were collected from power plants in the Central Appalachian basin and Colorado Plateau to determine the partitioning of As, Cr, Hg, Pb, and Se in coal combustion products (CCPs). The Appalachian plant burns a high-sulfur (about 3.9 wt.%) bituminous coal from the Upper Pennsylvanian Pittsburgh coal bed and operates with electrostatic precipitators (ESPs), with flue gas temperatures of about 163 °C in the ESPs. At this plant, As, Pb, Hg, and Se have the greatest median concentrations in FA samples, compared to BA and EFA. A mass balance (not including the FGD process) suggests that the following percentages of trace elements are captured in FA: As (48%), Cr (58%), Pb (54%), Se (20%), and Hg (2%). The relatively high temperatures of the flue gas in the ESPs and low amounts of unburned C in FA (0.5% loss-on-ignition for FA) may have led to the low amount of Hg captured in FA. The Colorado Plateau plant burns a blend of three low-S (about 0.74 wt.%) bituminous coals from the Upper Cretaceous Fruitland Formation and operates with fabric filters (FFs). Flue gas temperatures in the baghouses are about 104 °C. The elements As, Cr, Pb, Hg, and Se have the greatest median concentrations in the fine-grained fly ash product (FAP) produced by cyclone separators, compared to the other CCPs at this plant. The median concentration of Hg in FA (0.0983 ppm) at the Colorado Plateau plant is significantly higher than that for the Appalachian plant (0.0315 ppm); this higher concentration is related to the efficiency of FFs in Hg capture, the relatively low temperatures of flue gas in the baghouses (particularly in downstream compartments), and the amount of unburned C in FA (0.29% loss-on-ignition for FA).

  2. Some consideration on potentials of coal organic materials for chemicals

    SciTech Connect

    Nomura, Masakatsu; Artok, Levent; Su, Yan; Murata, Satoru

    1998-12-31

    According to the recent structural studies on bituminous coals, the presence of condensed aromatic nuclei and alicyclic portion in coal is considered to be more abundant than believed so far. Based on these data consideration of the potential of coal for chemical production is made by referring to the results on sodium dichromate-oxidation of Akabira coal and detailed analysis of vacuum residue from Illinois No.6 coal derived liquid. It is also stressed that to select the appropriate coal samples for either flash pyrolysis or hydroliquefaction based on their detailed structural index is important to attain their effective conversion. Three methods occurs in the minds of coal chemists, pyrolysis, direct liquefaction and indirect liquefaction. In this paper, the authors focus on the former two methods because indirect liquefaction makes use of carbon monoxide and hydrogen obtained in coal gasification, being not fitted in the present context of potentials of coal organic materials.

  3. Near-neutral oxidation of pyrite in coal slurry solids. Quarterly report, 1 December 1994--28 February 1995

    SciTech Connect

    Frost, J.K.; Dreher, G.B.

    1995-12-31

    In this research project we plan to determine the rate of oxidation of pyrite associated with coaly particles when the pH of the surrounding environment is held at approximately 7.8. Coaly particles that contain pyrite are generated during the preparation of Illinois Basin coal for market. These particles are discharged to an impoundment, which eventually must be reclaimed. The purpose for reclamation is either to prevent the Generation of acidic solution as the pyrite in the coal slurry solid reacts with air, or to prevent the migration of the acidic solution to a groundwater aquifer. The reclamation is usually accomplished by covering the impoundment with a four-foot-thick layer of topsoil. One possible alternative method for reclamation of a coal slurry impoundment is to mix in alkaline residue from the fluidized-bed combustion of coal. This codisposal would slow the production of acid and would also neutralize any acid produced. If the codisposal method is found to be environmentally acceptable, it will save the coal mining companies part of their cost of reclamation, and also provide a safe and useful disposal outlet for a portion of the residue that is Generated by the fluidized-bed combustion of coal.

  4. Hydrologic data for selected streams in the coal area of southeastern Oklahoma, July 1978 to September 1982

    USGS Publications Warehouse

    Blumer, S.P.; Alf, L.A.

    1987-01-01

    Hydrologic data on quantity and quality of surface waters were collected in the coal resource area of southeastern Oklahoma during an investigation of the effects of coal surface mining on the hydrology of the area. The objective of the study was to determine the characteristics of the regional hydrologic system and to detect and document changes in the system that may occur as the result of coal surface mining. This report presents data which were collected at 13 sites in 4 counties between July 1978 and September 1982. The data include: (1) mean daily stream discharge; (2) physical properties, selected field constituents, and concentration of suspended sediment of water samples; (3) concentration of selected common constituents, nutrients, and trace elements of water samples; (4) mean daily specific conductance, pH, water temperature, and dissolved oxygen; and (5) analyses of biological samples.

  5. Near-neutral oxidation of pyrite in coal slurry solids. Technical report, March 1--May 31, 1995

    SciTech Connect

    Frost, J.K.

    1995-12-31

    In this research project are determining the rate of oxidation of pyrite associated with coaly particles (coal slurry solid) when the pH of the surrounding environment is held at approximately 7.8. Coaly particles that contain pyrite are generated during the preparation of Illinois Basin coal for market. These particles are discharged to an impoundment, which eventually must be reclaimed. The purpose for reclamation is either to prevent the generation of acidic solution as the pyrite in the coal slurry solid reacts with air, or to prevent the migration of the acidic solution to a groundwater aquifer. The reclamation is usually accomplished by covering the impoundment with a four-foot-thick layer of topsoil. One possible alternative method for reclamation of a coal slurry impoundment is to mix in alkaline residue from the fluidized-bed combustion of coal. This codisposal would slow the production of acid and would also neutralize any acid produced. If the codisposal method is found to be environmentally acceptable, it will save the coal mining companies part of their cost of reclamation, and also provide a safe and useful disposal outlet for a portion of the residue that is generated by the fluidized-bed combustion of coal. Pyrite oxidation experiments were conducted during the quarter in the following manner. Air, free of carbon dioxide, is bubbled through water in a covered beaker. The pH is adjusted to 7.8 and the solution is circulated by a peristaltic pump through the coal slurry sample contained in a cellulose thimble in a Soxhlet tube mounted above the beaker. The pH of the solution is continuously statted to 7.8 by addition of NaOH solution. Samples are pipetted from the reaction solution for sulfate determination. The rate of oxidation of pyrite in coal slurry solids sample CSS-2a was calculated from the rate of production of sulfate ion to be 1.71 {times} 10{sup {minus}6} {micro}mole pyrite per minute per {micro}mole of pyrite present.

  6. Coal-gasification and tar-conversion reactions over calcium oxide. Annual progress report, August 1, 1981-October 31, 1982

    SciTech Connect

    Longwell, J.P.; Chang, C.S.; Peters, W.A.

    1983-01-01

    This research focusses on low temperature (723-1123 K) effects of calcium oxide on coal gasification and coal pyrolysis. The general objective of the present research is to investigate the chemistry and global kinetics of thermal reactions of freshly-formed tars in the presence of calcium oxide, and thereby assess the potential application for achieving improved overall gas yields and product quality in practical processes. Construction and debugging of the experimental system, designed to achieve this goal, have been completed. Preliminary runs showed that the system can be operated satisfactorily according to the design specifications. The extent of fresh tar cracking can be controlled by independently adjusting the major operating variables, such as reactor temperature, contact time (with active calcium oxide), and system pressure. The collection systems and the analytical techniques employed for characterizing the pyrolysis products have been identified. A standard procedure for reproducibly generating packed beds of active calcium oxide that exhibited minimal variation in stone surface area along their axis is under development. A 2-step calcination protocol shows promise for achieving this goal for well-defined experiments. Preliminary results of coal volatile generation and cracking experiments indicate that calcium oxide can drastically reduce the absolute yield of tars and significantly increase the production and yields of methane and ethylene gases. Overall material balances also appear to be satisfactory.

  7. Chemistry and origin of minor and trace elements in selected vitrinite concentrates from bituminous and anthracitic coals

    USGS Publications Warehouse

    Palmer, C.A.; Lyons, P.C.

    1990-01-01

    Twelve hand-picked vitrinite concentrates and companion whole-coal samples were analyzed for trace and minor elements by instrumental neutron activation analysis (INAA) and direct-current-arc spectrographic techniques (DCAS). The vitrinite concentrates contained 94 to nearly 100 vol.% vitrinite compared to 71-95 vol.% in the companion whole coals. The ash contents of the vitrinite concentrates were 2 to more than 190 times less than the ash contents of the companion whole coals. Organic and inorganic affinities were determined by comparing the elemental concentrations in the vitrinite concentrates to the concentrations in the companion whole coals. The ratios of these concentrations for 33 selected elements are shown in Figure 1. Ratios greater than 1 indicate organic affinity, and ratios less than 1 indicate inorganic affinity. Br and W generally showed organic affinity in all samples in this study. In the nine samples from the eastern United States (Fig. 1A-C) less than one-fourth of the trace elements show organic affinity compared to nearly one-half for the three English and Australian samples (Fig. 1D). The elements that generally show organic affinity in the non-U.S.A. samples studied include As, Cs, Hf, and Ni, which have generally inorganic affinities in the U.S.A. samples, and Cr, Sb, Se, and U, which have mixed (both organic and inorganic) affinities, in the U.S.A. coals studied, has an inorganic affinity in the English coals studied. B shows organic affinity in the samples from the Illinois basin (Fig. 1C). For the samples studied, Ba shows organic affinity in the Appalachian basin bituminous coals (Fig. 1B), inorganic affinity in the Illinois basin coals, and overall mixed affinities. In all the samples studied, Cu, Mn, Na, Sr, Ta, V, and Zn show mixed affinities, and A1, Co, Eu, Fe, Ga, K, La, Mg, Sc, Si, Th, Ti, and Ub have generally inorganic affinity. ?? 1990.

  8. Effect of Coal Contaminants on Solid Oxide Fuel System Performance and Service Life

    SciTech Connect

    Krishnan, Gopala N.; Jayaweera, Palitha; Perez, Jordi; Hornbostel, M.; Albritton, John R.; Gupta, Raghubir P.

    2007-10-31

    The U.S. Department of Energy’s SECA program envisions the development of high-efficiency, low-emission, CO2 sequestration-ready, and fuel-flexible technology to produce electricity from fossil fuels. One such technology is the integrated gasification-solid oxide fuel cell (SOFC) that produces electricity from the gas stream of a coal gasifier. SOFCs have high fuel-to-electricity conversion efficiency, environmental compatibility (low NOx production), and modularity. The primary objective of the Phase I study was to determine the sensitivity of the performance of solid oxide fuel cells to trace level contaminants present in a coal-derived gas stream in the temperature range 700° to 900°C. Laboratory-scale tests were performed with 1-inch diameter solid oxide fuel cells procured from InDec B.V., Netherlands. These cells produce 0.15, 0.27, and 0.35 W/cm2 at 700°, 750°, and 800°C, respectively, in a H2 anode feed and are expected to be stable within 10% of the original performance over a period of 2000 h. A simulated coal-derived gas containing 30.0% CO, 30.6% H2 11.8% CO2, 27.6% H2O was used at a rate of ~100 standard cm3/min to determine the effect of contaminants on the electrical performance of the cells. Alumina or zirconia components were used for the gas manifold to prevent loss of contaminants by reaction with the surfaces of the gas manifold Short-term accelerated tests were conducted with several contaminants including As, P, CH3Cl, HCl, Hg, Sb, and Zn vapors. In these tests, AsH3, PH3, Cd vapor and CH3Cl identified as the potential contaminants that can affect the electrical performance of SOFCs. The effect of some of these contaminants varied with the operating temperature. Cell failure due to contact break inside the anode chamber occurred when the cell was exposed to 10 ppm arsenic vapor at 800°C. The electrical performance of SOFC

  9. Advanced treatment of biologically pretreated coal gasification wastewater by a novel heterogeneous Fenton oxidation process.

    PubMed

    Zhuang, Haifeng; Han, Hongjun; Ma, Wencheng; Hou, Baolin; Jia, Shengyong; Zhao, Qian

    2015-07-01

    Sewage sludge from a biological wastewater treatment plant was converted into sewage sludge based activated carbon (SBAC) with ZnCl2 as activation agent, which was used as a support for ferric oxides to form a catalyst (FeOx/SBAC) by a simple impregnation method. The new material was then used to improve the performance of Fenton oxidation of real biologically pretreated coal gasification wastewater (CGW). The results indicated that the prepared FeOx/SBAC significantly enhanced the pollutant removal performance in the Fenton process, so that the treated wastewater was more biodegradable and less toxic. The best performance was obtained over a wide pH range from 2 to 7, temperature 30°C, 15 mg/L of H2O2 and 1g/L of catalyst, and the treated effluent concentrations of COD, total phenols, BOD5 and TOC all met the discharge limits in China. Meanwhile, on the basis of significant inhibition by a radical scavenger in the heterogeneous Fenton process as well as the evolution of FT-IR spectra of pollutant-saturated FeOx/BAC with and without H2O2, it was deduced that the catalytic activity was responsible for generating hydroxyl radicals, and a possible reaction pathway and interface mechanism were proposed. Moreover, FeOx/SBAC showed superior stability over five successive oxidation runs. Thus, heterogeneous Fenton oxidation of biologically pretreated CGW by FeOx/SBAC, with the advantages of being economical, efficient and sustainable, holds promise for engineering application.

  10. Selection of fluxing agent for coal ash and investigation of fusion mechanism: a first-principles study

    SciTech Connect

    Jie Li; Mei-Fang Du; Zhong-Xiao Zhang; Rong-Qing Guan; Yu-Shuang Chen; Ting-Yu Liu

    2009-01-15

    An approach based on the ab initio quantum chemical modeling (CASTEP, generalized gradient approximation (GGA), and density functional theory (DFT)) was first employed to guide the selection of the appropriate fluxing agent to reduce the coal ash melting temperature. Two kinds of typical Chinese coal ash A and B with a high-melting temperature were chosen as the investigated subjects. Result of the calculation shows that mullite mineral, which is the main component of coal ash, is easier to combine with an electron acceptor than with an electron donor. Because the cations of borax (Na{sub 2}B{sub 4}O{sub 7}10H{sub 2}O) and limestone can act as electron acceptors, borax and limestone were selected as the fluxing agents in our experiment. Results of the experiment show that the melting temperatures of coal ash A and B are both decreased by borax and limestone, respectively. Moreover, borax has a better fluxing effect than limestone under the same conditions. The further numerical study on the coal ash fusing mechanism indicates that the Na{sup +} and Ca{sup 2+} cations, as acceptors, can enter into the crystal lattice of mullite mainly through O(7) and O(8) and then cause the Al(6)-O(8) and Al(5)-O(7) bonds to rupture in the (AlO{sub 6})-octahedron. From this, mullite is forced to transform to feldspar and corundum minerals that have a low binding energy. Because of the phase change of minerals in the coal ash, the coal ash melting temperature is decreased by adding borax and limestone. 27 refs., 8 figs., 3 tabs.

  11. Selective methane oxidation over promoted oxide catalysts. Topical report, September 8, 1992--September 7, 1996

    SciTech Connect

    Klier, K.; Herman, R.G.

    1996-12-31

    The objective of this research was to selectively oxidize methane to C{sub 2} hydrocarbons and to oxygenates, in particular formaldehyde and methanol, in high space time yields using air at the oxidant under milder reaction conditions that heretofore employed over industrially practical oxide catalysts. The research carried out under this US DOE-METC contract was divided into the following three tasks: Task 1, maximizing selective methane oxidation to C{sub 2}{sup +} products over promoted SrO/La{sub 2}O{sub 3} catalysts; Task 2, selective methane oxidation to oxygenates; and Task 3, catalyst characterization and optimization. Principal accomplishments include the following: the 1 wt% SO{sub 4}{sup 2{minus}}/SrO/La{sub 2}O{sub 3} promoted catalyst developed here produced over 2 kg of C{sub 2} hydrocarbons/kg catalyst/hr at 550 C; V{sub 2}O{sub 5}/SiO{sub 2} catalysts have been prepared that produce up to 1.5 kg formaldehyde/kg catalyst/hr at 630 C with low CO{sub 2} selectivities; and a novel dual bed catalyst system has been designed and utilized to produce over 100 g methanol/kg catalyst/hr at 600 C with the presence of steam in the reactant mixture.

  12. Sulfur species leached from pyrite during oxidative desulfurization of coal in alkaline solutions

    SciTech Connect

    Stephenson, M.D.; Wheelock, T.D.; Markuszewski, R.

    1983-01-01

    The results indicate that thiosulfate, sulfite, and sulfate are the principal soluble sulfur species produced when coal-derived pyrite leached with a hot alkaline solution containing dissolved oxygen. The distribution of soluble sulfur species in the leachate was found to depend on leaching temperature, oxygen partial pressure, leachant composition, and time of contact. At lower temperatures and oxygen partial pressures and with a short time of contact between the leaching solution and pyrite, the leachate sulfur species were dominated by thiosulfate. However, the leachate also contained significant amounts of sulfite and sulfate. When the temperature, oxygen partial pressure, or time of contact were increased, the proportions of thiosulfate and sulfite decreased and the proportion of sulfate increased. It was observed also that reacted pyrite particles catalyzed the oxidation of thiosulfate to sulfite and sulfate. Consequently when pyrite was oxidized in a stirred reactor for 1 h at elevated temperature and oxygen partial pressure, most of the dissolved sulfur appeared as sulfate and very little as thiosulfate or sulfite. 10 references, 4 figures, 1 table.

  13. Coal desulfurization in oxidative acid media using hydrogen peroxide and ozone: a kinetic and statistical approach

    SciTech Connect

    F.R. Carrillo-Pedroza; A. Davalos Sanchez; M. Soria-Aguilar; E.T. Pecina Trevino

    2009-07-15

    The removal of pyritic sulfur from a Mexican sub-bituminous coal in nitric, sulfuric, and hydrochloric acid solutions was investigated. The effect of the type and concentration of acid, in the presence of hydrogen peroxide and ozone as oxidants, in a temperature range of 20-60{sup o}C, was studied. The relevant factors in pyrite dissolution were determined by means of the statistical analysis of variance and optimized by the response surface method. Kinetic models were also evaluated, showing that the dissolution of pyritic sulfur follows the kinetic model of the shrinking core model, with diffusion through the solid product of the reaction as the controlling stage. The results of statistical analysis indicate that the use of ozone as an oxidant improves the pyrite dissolution because, at 0.25 M HNO{sub 3} or H{sub 2}SO{sub 4} at 20{sup o}C and 0.33 g/h O{sub 3}, the obtained dissolution is similar to that of 1 M H{sub 2}O{sub 2} and 1 M HNO{sub 3} or H{sub 2}SO{sub 4} at 40{sup o}C. 42 refs., 9 figs., 3 tabs.

  14. Reversible Poisoning of the Nickel/Zirconia Solid Oxide Fuel Cell Anodes by Hydrogen Chloride in Coal Gas

    SciTech Connect

    Marina, Olga A.; Pederson, Larry R.; Thomsen, Edwin C.; Coyle, Christopher A.; Yoon, Kyung J.

    2010-10-15

    The performance of anode-supported solid oxide fuel cells (SOFC) was evaluated in synthetic coal gas containing HCl in the temperature range 650 to 850oC. Exposure to up to 800 ppm HCl resulted in reversible poisoning of the Ni/zirconia anode by chlorine species adsorption, the magnitude of which decreased with increased temperature. Performance losses increased with the concentration of HCl to ~100 ppm, above which losses were insensitive to HCl concentration. Cell voltage had no effect on poisoning. No evidence was found for long-term degradation that can be attributed to HCl exposure. Similarly, no evidence of microstructural changes or formation of new solid phases as a result of HCl exposure was found. From thermodynamic calculations, solid nickel chloride phase formation was shown to be highly unlikely in coal gas. Further, the presence of HCl at even the highest anticipated concentrations in coal gas would minimally increase the volatility of nickel.

  15. Kinetically driven instabilities and selectivities in methane oxidation

    SciTech Connect

    Park, Y.K.; Vlachos, D.G.

    1997-08-01

    Ignitions, extinctions, and Hopf bifurcations in methane oxidation were studied as a function of pressure and inlet fuel composition. A continuous stirred-tank reactor was modeled with numerical bifurcation techniques, using the 177 reaction/31 species mechanism. Sensitivity and reaction pathway analyses were performed at turning points to identify the most important reactions and reactive species. Then, simulations were compared with experimental data. Multiple ignitions and extinctions as well as oscillations that are purely kinetically driven were found. Ignition to a partially ignited state with considerable reactivity of methane indicates possible narrow operation windows with high selectivities to partial oxidation products. At 0.1 atm, the authors found a selectivity of up to 80% to CO at 70% CH{sub 4} conversion. The ignition to a fully ignited branch is associated with high selectivity to CO{sub 2} and H{sub 2}O. The C2 chemistry inhibits the ignition of methane to the partially ignited branch. The methane ignition temperature exhibits two branches with respect to pressure, with only the low-pressure branch being dominant. Reaction path analysis at ignition conditions shows that the preferred pathway of CH{sub 4} oxidation is to form CO and CO{sub 2} though CH{sub 2}O and CH{sub 2}(s) intermediates. However, at intermediate to high pressures, the recombination of CH{sub 3} to C{sub 2}H{sub 6} also becomes quite significant.

  16. Bioenergetic studies of coal sulfur oxidation by extremely thermophilic bacteria. Final report, September 15, 1992--August 31, 1997

    SciTech Connect

    Kelly, R.M.; Han, C.J.

    1997-12-31

    Thermoacidophilic microorganisms have been considered for inorganic sulfur removal from coal because of expected improvements in rates of both biotic and abiotic sulfur oxidation reactions with increasing temperature. In this study, the bioenergetic response of the extremely thermoacidophilic archaeon, Metallosphaera sedula, to environmental changes have been examined in relation to its capacity to catalyze pyrite oxidation in coal. Given an appropriate bioenergetic challenge, the metabolic response was to utilize additional amounts of energy sources (i.e., pyrite) to survive. Of particular interest were the consequences of exposing the organism to various forms of stress (chemical, nutritional, thermal, pH) in the presence of coal pyrite. Several approaches to take advantage of stress response to accelerate pyrite oxidation by this organism were examined, including attempts to promote acquired thermal tolerance to extend its functional range, exposure to chemical uncouplers and decouplers, and manipulation of heterotrophic and chemolithotrophic tendencies to optimize biomass concentration and biocatalytic activity. Promising strategies were investigated in a continuous culture system. This study identified environmental conditions that promote better coupling of biotic and abiotic oxidation reactions to improve biosulfurization rates of thermoacidophilic microorganisms.

  17. Geochemistry and petrology of selected coal samples from Sumatra, Kalimantan, Sulawesi, and Papua, Indonesia

    USGS Publications Warehouse

    Belkin, H.E.; Tewalt, S.J.; Hower, J.C.; Stucker, J.D.; O'Keefe, J. M. K.

    2009-01-01

    Indonesia has become the world's largest exporter of thermal coal and is a major supplier to the Asian coal market, particularly as the People's Republic of China is now (2007) and perhaps may remain a net importer of coal. Indonesia has had a long history of coal production, mainly in Sumatra and Kalimantan, but only in the last two decades have government and commercial forces resulted in a remarkable coal boom. A recent assessment of Indonesian coal-bed methane (CBM) potential has motivated active CBM exploration. Most of the coal is Paleogene and Neogene, low to moderate rank and has low ash yield and sulfur (generally < 10 and < 1??wt.%, respectively). Active tectonic and igneous activity has resulted in significant rank increase in some coal basins. Eight coal samples are described that represent the major export and/or resource potential of Sumatra, Kalimantan, Sulawesi, and Papua. Detailed geochemistry, including proximate and ultimate analysis, sulfur forms, and major, minor, and trace element determinations are presented. Organic petrology and vitrinite reflectance data reflect various precursor flora assemblages and rank variations, including sample composites from active igneous and tectonic areas. A comparison of Hazardous Air Pollutants (HAPs) elements abundance with world and US averages show that the Indonesian coals have low combustion pollution potential.

  18. Geochemical Niches of Iron-Oxidizing Acidophiles in Acidic Coal Mine Drainage

    PubMed Central

    Kohl, Courtney; Grettenberger, Christen; Larson, Lance N.; Burgos, William D.

    2014-01-01

    A legacy of coal mining in the Appalachians has provided a unique opportunity to study the ecological niches of iron-oxidizing microorganisms. Mine-impacted, anoxic groundwater with high dissolved-metal concentrations emerges at springs and seeps associated with iron oxide mounds and deposits. These deposits are colonized by iron-oxidizing microorganisms that in some cases efficiently remove most of the dissolved iron at low pH, making subsequent treatment of the polluted stream water less expensive. We used full-cycle rRNA methods to describe the composition of sediment communities at two geochemically similar acidic discharges, Upper and Lower Red Eyes in Somerset County, PA, USA. The dominant microorganisms at both discharges were acidophilic Gallionella-like organisms, “Ferrovum” spp., and Acidithiobacillus spp. Archaea and Leptospirillum spp. accounted for less than 2% of cells. The distribution of microorganisms at the two sites could be best explained by a combination of iron(II) concentration and pH. Populations of the Gallionella-like organisms were restricted to locations with pH >3 and iron(II) concentration of >4 mM, while Acidithiobacillus spp. were restricted to pH <3 and iron(II) concentration of <4 mM. Ferrovum spp. were present at low levels in most samples but dominated sediment communities at pH <3 and iron(II) concentration of >4 mM. Our findings offer a predictive framework that could prove useful for describing the distribution of microorganisms in acid mine drainage, based on readily accessible geochemical parameters. PMID:25501473

  19. Interaction of iron-copper mixed metal oxide oxygen carriers with simulated synthesis gas derived from steam gasification of coal

    SciTech Connect

    Siriwardane, Ranjani V.; Ksepko, Ewelina; Tian, Hanging

    2013-01-01

    The objective of this work was to prepare supported bimetallic Fe–Cu oxygen carriers and to evaluate their performance for the chemical-looping combustion (CLC) process with simulated synthesis gas derived from steam gasification of coal/air. Ten-cycle CLC tests were conducted with Fe–Cu oxygen carriers in an atmospheric thermogravimetric analyzer utilizing simulated synthesis gas derived from the steam gasification of Polish Janina coal and Illinois #6 coal as fuel. The effect of temperature on reaction rates, chemical stability, and oxygen transport capacity were determined. Fractional reduction, fractional oxidation, and global rates of reactions were calculated from the thermogravimetric analysis (TGA) data. The supports greatly affected reaction performance. Data showed that reaction rates and oxygen capacities were stable during the 10-cycle TGA tests for most Fe–Cu/support oxygen carriers. Bimetallic Fe–Cu/support oxygen carriers showed higher reduction rates than Fe-support oxygen carriers. The carriers containing higher Cu content showed better stabilities and better reduction rates. An increase in temperature from 800 °C to 900 °C did not have a significant effect on either the oxygen capacity or the reduction rates with synthesis gas derived from Janina coal. Oxidation reaction was significantly faster than reduction reaction for all supported Fe–Cu oxygen carriers. Carriers with higher Cu content had lower oxidation rates. Ten-cycle TGA data indicated that these oxygen carriers had stable performances at 800–900 °C and might be successfully used up to 900 °C for coal CLC reaction in the presence of steam.

  20. Selective methane oxidation over promoted oxide catalysts. Quarterly report, March--May 1995

    SciTech Connect

    Klier, K.; Herman, R.G.; Wang, Chaun-Bao; Shi, Chunlei; Sun, Qun

    1995-08-01

    The objective of this research is the selective oxidative coupling of methane to C{sub 2}H{sub 4} hydrocarbons and oxygenates, in particular formaldehyde and methanol. Air, oxygen or carbon dioxide, rather than nitrous oxide will be utilized as the oxidizing gas at high gas hourly space velocity, but mild reaction conditions (500-700 {degrees}C, 1 atm total pressure). All the investigated processes are catalytic, aiming at minimizing gas phase reactions that are difficult to control. The research is divided into the following three tasks: (1) maximizing selective methane oxidation to C{sub 2}H{sub 4} products over promoted Sr/La{sub 2}O{sub 3}; (2) selective methane oxidation to oxygenates; and (3) catalyst characterization and optimization. Task 1 dealt with the preparation, testing, and optimization of acidic promoted lanthana-based catalysts for the synthesis of C{sub 2}H{sub 4} hydrocarbons and is essentially completed. Task 2 aims at the formation and optimization of promoted catalysts for the synthesis of oxygenates, in particular formaldehyde and methanol. Task 3 involves characterization of the most promising catalysts so that optimization can be achieved under Task 2. Accomplishments for this period are presented.

  1. Effects of coal mining on the hydrologic environment of selected stream basins in southern West Virginia. Water resources investigation

    SciTech Connect

    Borchers, J.W.; Ehlke, T.A.; Mathes, M.V.; Downs, S.C.

    1991-01-01

    The study was undertaken to help answer questions about the effects of coal mining on streamflow characteristics, stream-water quality, ground-water flow and availability, ground-water quality, concentration, loading and types of suspended sediment in streams, and biological life in streams. Three mined basins and two unmined control basins in southern West Virginia were selected for study. The report defines the effects of coal mining on the hydrologic environment of small stream basins in southern West Virginia. It answers some of the questions that have been raised by coal companies, regulatory agencies, environmental groups, researchers, and the public. The report compares hydrologic data collected in unmined basins to data collected in deep-mined and surface-mined basins. The data include the measurement and description of precipitation, streamflow, ground-water levels, suspended sediment, stream and ground-water quality, and benthic invertebrate life in streams.

  2. Air toxics in coal: Distribution and abundance of selected trace elements in the Powder River Basin

    SciTech Connect

    Crowley, S.S.; Stanton, R.W.

    1994-12-31

    The 1990 Clean Air Act Amendments identified 12 potentially toxic elements, called ``air toxics,`` that may be released during the combustion of coal. The elements identified in the amendments are As, Be, Cd, Cr, Co, Hg, Mn, Ni, Pb, Sb, Se, and U (radionuclides). In this study, the distribution and concentration of these elements were examined, on a whole-coal basis, in samples from two cores of the Wyodak-Anderson coal bed (Paleocene, Tongue River Member of the Fort Union Formation), in the Powder River Basin of Wyoming. The distribution of these elements in the Wyodak-Anderson coal bed is also compared to the distribution of the same elements in a correlative coal bed, the Anderson-Dietz 1 coal bed in the Powder River Basin of Montana.

  3. Biodesulfurization techniques: Application of selected microorganisms for organic sulfur removal from coals. Final report

    SciTech Connect

    Elmore, B.B.

    1993-08-01

    As an alternative to post-combustion desulfurization of coal and pre-combustion desulfurization using physicochemical techniques, the microbial desulfurization of coal may be accomplished through the use of microbial cultures that, in an application of various microbial species, may remove both the pyritic and organic fractions of sulfur found in coal. Organisms have been isolated that readily depyritize coal but often at prohibitively low rates of desulfurization. Microbes have also been isolated that may potentially remove the organic-sulfur fraction present in coal (showing promise when acting on organic sulfur model compounds such as dibenzothiophene). The isolation and study of microorganisms demonstrating a potential for removing organic sulfur from coal has been undertaken in this project. Additionally, the organisms and mechanisms by which coal is microbially depyritized has been investigated. Three cultures were isolated that grew on dibenzothiophene (DBT), a model organic-sulfur compound, as the sole sulfur source. These cultures (UMX3, UMX9, and IGTS8) also grew on coal samples as the sole sulfur source. Numerous techniques for pretreating and ``cotreating`` coal for depyritization were also evaluated for the ability to improve the rate or extent of microbial depyritization. These include prewashing the coal with various solvents and adding surfactants to the culture broth. Using a bituminous coal containing 0.61% (w/w) pyrite washed with organic solvents at low slurry concentrations (2% w/v), the extent of depyritization was increased approximately 25% in two weeks as compared to controls. At slurry concentrations of 20% w/v, a tetrachloroethylene treatment of the coal followed by depyritization with Thiobacillus ferrooxidans increased both the rate and extent of depyritization by approximately 10%.

  4. Sulfur and ash reduction potential and selected chemical and physical properties of United States coals. [Contains glossary

    SciTech Connect

    Cavallaro, J.A.; Deurbrouck, A.W.; Killmeyer, R.P.; Fuchs, W. . Coal Preparation Div.); Jacobsen, P.S. )

    1991-02-01

    This report presents the washability and comprehensive characterization results of 184 raw coal channel samples, including anthracite, bituminous and lignite coals, collected from the Central Region of the United States. This is the second of a three volume report on the coals of the United States. All the data are presented in six appendices. Statistical techniques and definitions are presented in Appendix A, and a glossary of terms is presented in Appendix B. The complete washability data and an in-depth characterization of each sample are presented alphabetically by state in Appendix C. In Appendix D, a statistical evaluation is given for the composited washability data, selected chemical and physical properties and washability data interpolated at various levels of Btu recovery. This presentation is shown by state, section, and region where four or more samples were collected. Appendix E presents coalbed codes and names for the Central Region coals. Graphical summations are presented by state, section and region showing the effects of crushing on impurity reductions, and the distribution of raw and clean coal samples meeting various levels of SO{sub 2} emissions. 35 figs., 5 tabs.

  5. Protocols for the selective cleavage of carbon-sulfur bonds in coal. Technical report, March 1, 1992--May 30, 1992

    SciTech Connect

    Bausch, M.

    1992-10-01

    Chemical reactions that result in carbon-sulfur bond cleavage are an essential aspect of any protocol designed to remove organic sulfur from coal. Unfortunately, several classes of reactions that lead to carbon-sulfur bond cleavage are not well understood. Planned in ``Protocols for the Selective Cleavage of Carbon-Sulfur Bonds in Coal`` are reactions in which organic sulfur-containing coal model compounds are subjected to different conditions of temperature, solvent mixtures and radiation. Summarized in this quarterly report are results of our investigations of the following topics: (a) the reactions of coal model compounds, namely, benzyl phenyl sulfide (BPS), diphenyl sulfide (hereafter referred to as phenylsulfide, PS) and dibenzothiophene (DBT) with various reagents (Lewis acid catalysts, radical initiators, electron acceptors) using different solvents and temperature in an attempt to maximize the degree of carbon-sulfur (C-S) bond cleavage; and (b) the results of photooxidation of coal model compounds under controlled conditions. Quantitative product analyses are presented in this report.

  6. Highly-Efficient Buried-Oxide-Waveguide Laser by selective Oxidation

    SciTech Connect

    VAWTER,GREGORY A.; SPAHN,OLGA B.; ALLERMAN,ANDREW A.; GAO,YING

    2000-02-15

    An edge-emitting buried-oxide waveguide (BOW) laser structure employing lateral selective oxidation of AlGaAs layers above and below the active region for waveguiding and current confinement is presented. This laser configuration has the potential for very small lateral optical mode size and high current confinement and is well suited for integrated optics applications where threshold current and overall efficiency are paramount. Optimization of the waveguide design, oxide layer placement, and bi-parabolic grading of the heterointerfaces on both sides of the AlGaAs oxidation layers has yielded 95% external differential quantum efficiency and 40% wall-plug efficiency from a laser that is very simple to fabricate and does not require epitaxial regrowth of any kind.

  7. Effects of pretreatment of coal by CO{sub 2} on nitric oxide emission and unburned carbon in various combustion environments

    SciTech Connect

    Gathitu, B.B.; Chen, W.Y.

    2009-12-15

    Polar solvents are known to swell coal, break hydrogen bonds in the macromolecular structure, and enhance coal liquefaction efficiencies. The effects of the pretreatment of coal using supercritical CO{sub 2} on its physical structure and combustion properties have been studied at the bench-scale level. Emphasis has been placed on NO reburning, NO emissions during air-fired and oxy-fired combustion, and loss on ignition (LOI). Pretreatment was found to increase porosity and to significantly alter the fuel nitrogen reaction pathways. Consequently, NO reduction during reburning using bituminous coal increased, and NO emissions during oxidation of lignite decreased. These two benefits were achieved without negative impacts on LOI.

  8. Separation of aromatic carboxylic acids using quaternary ammonium salts on reversed-phase HPLC. 2. Application for the analysis of Loy Yang coal oxidation products

    SciTech Connect

    Kawamura, K.; Okuwaki, A.; Verheyen, T.V.; Perry, G.J.

    2006-07-01

    In order to develop separation processes and analytical methods for aromatic carboxylic acids for the coal oxidation products, the separation behavior of aromatic carboxylic acids on a reversed-phase HPLC using eluent containing quaternary ammonium salt was optimized using the solvent gradient method. This method was applied for the analysis of Loy Yang coal oxidation products. It was confirmed that the analytical data using this method were consistent with those determined using gas chromatography.

  9. Hydrology of the Price River basin, Utah, with emphasis on selected coal-field areas

    USGS Publications Warehouse

    Waddell, Kidd M.; Dodge, J.E.; Darby, D.W.; Theobald, S.M.

    1986-01-01

    Data obtained during a hydrologic study of the Price River basin, Utah, are used to describe seasonal variations of flow of springs, relation between ground water and surface water, hydraulic properties of the ground-water reservoir, ground-water recharge and discharge, flood characteristics of streams, mineralogic composition and depositional rates of sediments, nutrient and inorganic loading in streams and Scofield Reservoir, and water budgets for selected basins. Additional study and monitoring are needed to detect possible hydrologic changes caused by coal mining. Much of the ground-water discharge from the Star Point Sandstone in the Mesaverde Group in the Wasatch Plateau occurs along faults. In the Book Cliffs, where faulting is less extensive, most of the ground-water discharge is from the Flagstaff Limestone. The Flagstaff Limestone is greatly diffusive, has a small storage coefficient, and contains water which is perched. Springs issuing from the Star Point Sandstone in the Mud Creek drainage (Wasatch Plateau) had recession indexes greater than 365 days per log cycle. Springs issuing at higher altitudes from the Colton Formation and the Flagstaff Limestone in the Soldier Creek area (Book Cliffs) have great seasonal variability, with recession indexes ranging from 24 to 115 days per log cycle. Estimated transmissivities in the Soldier Creek area ranged from 0.003 foot squared per day in the lower part of the Castlegate Sandstone to 0.07 foot squared per day in the Price River Formation. Seepage from the Star Point Sandstone is the major contributor to base flow of the stream in Eccles Canyon (Wasatch Plateau). Gains of as much as 230 gallons per minute occurred near a fault zone which crosses Eccles Canyon at the junction with South Fork Canyon. The potentiometric surface of water in the Blackhawk Formation in the Wasatch Plateau (Mud Creek drainage) and the Book Cliffs (Soldier Creek area) generally is above the coal zones, and dewatering will be necessary

  10. Oxide ion transport for selective oxidative coupling of methane with new membrane reactor

    SciTech Connect

    Nozaki, Takao; Fujimoto, Kaoru . Dept. of Synthetic Chemistry)

    1994-05-01

    Oxidative coupling of methane was conducted by using membrane reactors. The nonporous membrane film that consisted of PbO modified by alkaline or alkaline earth compound was supported on porous SiO[sub 2]-Al[sub 2]O[sub 3] tube. Higher hydrocarbons were successfully synthesized with high selectivity (about 90%). A kinetic analysis was conducted to clarify whether oxide ion transportation through PbO film participated in the oxidative coupling of methane. The evaluated value of the diffusion coefficient of oxide ion transport based on the methane oxidation agreed well with that of published data. The simulated gradient of the oxide ion concentration through the PbO membrane agreed well with that measured by electron probe X-ray microanalyzer. A transient response simulated by using kinetic parameters evaluated from steady-state analysis also agreed well with the experiment. These results prove the validity of the reaction model that consists of surface reactions of methane with oxide ion which is transferred from inside to outside of the membrane reactor. Alkali modifiers on the PbO membrane surface exhibited a promotional effect on the surface reaction of methane coupling. Another membrane reactor containing Bi[sub 2]O[sub 3] showed higher activity than the PbO membrane.

  11. Cobalt-promoted Iron Oxide Nanoparticles for the Selective Oxidative Dehydrogenation of Cyclohexane

    NASA Astrophysics Data System (ADS)

    Rutter, Matthew

    Recent work has shown that both cobalt and iron oxide nanoparticles are active for the oxidative dehydrogenation (ODH) of cyclohexane to benzene, the former more active than the latter. Further study has shown that the addition of gold species as a minority component into iron oxide nanocrystals increases the selectivity of the reaction to benzene. Since a primary motivation for this work is the addition of catalysts in jet fuels to facilitate the dehydrogenation and cracking reactions preceding their combustion, a low-cost, sacrificial catalyst is sought after. In this application, catalyst nanoparticles suspended in the fuel stream will dehydrogenate cyclic alkanes (cyclohexane) to their aromatic counterparts (benzene). Alkenes and aromatics have a much higher rate of combustion, which decreases the amount of uncombusted fuel in the exhaust, thereby increasing performance. As these catalysts are not recyclable, there is significant impetus to substitute cheaper base metals for expensive noble metals. In this work, iron oxide nanoparticles are doped with varying levels of cobalt to examine the effect of cobalt content and oxidation state on the selectivity and activity of the iron oxide for the oxidative dehydrogenation of cyclohexane, used as a model cyclic alkane in jet fuel. We have shown previously that small (˜5nm) cobalt oxide nanoparticles favor the production of benzene over the partial dehydrogenation products cyclohexene and cyclohexadiene, or the complete oxidation product carbon dioxide. It is the aim of this work to examine the surface of these cobalt-iron oxide nanoparticles to determine the conditions most favorable for this selective oxidative dehydrogenation. Cobalt-doped iron nanoparticles were prepared by a surfactant-free hydrothermal co-precipitation technique that enabled a high degree of composition control and size control. These samples were characterized via Transmission Electron Microscopy (TEM), powder X-Ray Diffraction (XRD), X

  12. Exergy and Economic Analysis of Catalytic Coal Gasifiers Coupled With Solid Oxide Fuel Cells

    SciTech Connect

    Siefert, Nicholas; Litster, Shawn

    2011-01-01

    The National Energy Technology Laboratory (NETL) has undertaken a review of coal gasification technologies that integrate with solid oxide fuel cells (SOFC) to achieve system efficiencies near 60% while capturing and sequestering >90% of the carbon dioxide. One way to achieve an overall system efficiency of greater than 60% is in a power plant in which a catalytic coal gasifier produces a syngas with a methane composition of roughly 25% on a dry volume basis and this is sent to a SOFC, with CO{sub 2} capture occurring either before or after the SOFC. Integration of a catalytic gasifier with a SOFC, as opposed to a conventional entrained flow gasifier, is improved due to (a) decreased exergy destruction inside a catalytic, steam-coal gasifier producing a high-methane content syngas, and (b) decreased exergy destruction in the SOFC due to the ability to operate at lower air stoichiometric flow ratios. For example, thermal management of the SOFC is greatly improved due to the steam-methane reforming in the anode of the fuel cell. This paper has two main goals. First, we converted the levelized cost of electricity (LCOE) estimates of various research groups into an average internal rate of return on investment (IRR) in order to make comparisons between their results, and to underscore the increased rate of return on investment for advanced integrated gasification fuel cell systems with carbon capture & sequestration (IGFC-CCS) compared with conventional integrated gasification combined cycle (IGCC-CCS) systems and pulverized coal combustion (PCC-CCS) systems. Using capital, labor, and fuel costs from previous researchers and using an average price of baseload electricity generation of $61.50 / MW-hr, we calculated inflation-adjusted IRR values of up to 13%/yr for catalytic gasification with pressurized fuel cell and carbon dioxide capture and storage (CCS), whereas we calculate an IRR of ~4%/yr and ~2%/yr for new, conventional IGCC-CCS and PCC-CCS, respectively. If the

  13. Silicone glycol collectors in the beneficiation of fine coal by froth flotation

    SciTech Connect

    Owen, M.J.

    1985-07-02

    A froth flotation process for the beneficiation of fine coal is disclosed which employs as a collector a water-dispersible polyorganosiloxane or a mixture of water-dispersible polyorganosiloxanes which contain organic radicals selected from the group consisting of polyethylene oxide and polypropylene oxide radicals. The process of this invention is especially useful for the beneficiation of difficult-to-float fine coals.

  14. Hierarchical zeolites and their catalytic performance in selective oxidative processes.

    PubMed

    Ojeda, Manuel; Grau-Atienza, Aida; Campos, Rafael; Romero, Antonio A; Serrano, Elena; Maria Marinas, Jose; García Martínez, Javier; Luque, Rafael

    2015-04-24

    Hierarchical ZSM-5 zeolites prepared using a simple alkali treatment and subsequent HCl washing are found to exhibit unprecedented catalytic activities in selective oxidation of benzyl alcohol under microwave irradiation. The metal-free zeolites promote the microwave-assisted oxidation of benzyl alcohol with hydrogen peroxide in yields ranging from 45-35 % after 5 min of reaction under mild reaction conditions as well as the epoxidation of cyclohexene to valuable products (40-60 % conversion). The hierarchically porous systems also exhibited an interesting catalytic activity in the dehydration of N,N-dimethylformamide (25-30 % conversion), representing the first example of transition-metal free catalysts in this reaction.

  15. Thermal Behavior Study of the MoVTeNb Oxide Catalyst for Selective Oxidation Process

    SciTech Connect

    Idris, R.; Hamid, S. B. Abd.

    2009-06-01

    Several parameters involved in preparing the multi metal oxide (MMO) catalysts (Mo{sub 1}V{sub 0.3}Te{sub 0.23}Nb{sub 0.12}O{sub x}) for selective oxidation of propane to acrylic acid (AA) were investigated. These included the proper pre-calcined and calcinations atmosphere effect on the performance of the catalysts. It was found that each metal element plays a critical role to the performance of an effective catalyst and also the calcinations under a non-flow inert atmosphere. The characterization results from XRD, SEM, TG and DSC show the important differences depending on the activation procedures of the MoVTeNb oxide catalyst. The XRD analysis is used to identify the phase inventory of the MoVTeNb oxide catalysts. The structure of orthorhombic M1, M2, TeMo{sub 5}O{sub 16}, V{sub 0.95}Mo{sub 0.97}O{sub 5} and Mo{sub 5}O{sub 14} phase was investigated. The orthorhombic M1 phase is the most active and selective phase and is responsible for the major of the efficiently of the best catalyst for selective oxidation process. TGA and DTG allow the identification of the number and types, of reactions involving evaporation of small molecules from removal of ligands and water to condensation or drying processes. From all these analyses it was proven that the activation procedures would affect the performance of the MoVTeNb oxide catalyst.

  16. SUBMICROSCOPIC ( less than 1 mu m) MINERAL CONTENTS OF VITRINITES IN SELECTED BITUMINOUS COAL BEDS.

    USGS Publications Warehouse

    Minkin, J.A.; Chao, E.C.T.; Thompson, C.L.; Wandless, M.-V.; Dulong, F.T.; Larson, R.R.; Neuzil, S.G.; ,

    1983-01-01

    An important aspect of the petrographic description of coal is the characterization of coal quality, including chemical attributes. For geologic investigations, data on the concentrations, distribution, and modes of occurrence of minor and trace elements provide a basis for reconstructing the probable geochemical environment of the swamp material that was converted into peat, and the geochemical conditions that prevailed during and subsequent to coalification. We have been using electron (EPMA) and proton (PIXE) microprobe analytical methods to obtain data on the chemical characteristics of specific coal constituents in their original associations within coal samples. The present study is aimed at evaluation of the nature of mineral occurrences and heterogeneous elemental concentrations within vitrinites. Vitrinites are usually the most abundant, and therefore most important, maceral group in bituminous coal. 8 refs.

  17. An assessment of the quality of selected EIA data series: Coal data, 1983--1988

    SciTech Connect

    Not Available

    1991-11-25

    The purpose of this report is to present information on the quality of some of the Energy Information Administration`s (EIA) coal data. This report contains discussions of data on production, direct labor hours, recoverable reserves, and prices from 1983 through 1988. Chapter 2 of this report presents a summary of the EIA coal data collection and identifies other sources providing similar data. Chapters 3 and 4 focus on data on coal production and direct labor hours, respectively. Detailed comparisons with data from the Mine Safety and Health Administration (MSHA) and State mining agencies are presented. Chapter 5 examines recoverable reserves. Included are internal comparisons as well as comparisons with other published reserve-related data, namely those of BXG, Inc. Chapter 6 describes how EIA obtains estimates of coal prices and discusses the variability in the prices caused by factors such as mine type, coal rank, and region. 5 figs., 5 tabs.

  18. PILOT-SCALE STUDY OF THE EFFECT OF SELECTIVE CATALYTIC REDUCTION CATALYST ON MERCURY SPECIATION IN ILLINOIS AND POWDER RIVER BASIN COAL COMBUSTION FLUE GASES

    EPA Science Inventory

    A study was conducted to investigate the effect of selective catalytic reduction (SCR) catalyst on mercury (Hg) speciation in bituminous and subbituminous coal combustion flue gases. Three different Illinois Basin bituminous coals (from high to low sulfur and chlorine) and one Po...

  19. A summary of selected publications, project activities, and data sources related to hydrology in the Warrior and Plateau coal fields of Alabama

    USGS Publications Warehouse

    Kidd, Robert E.; Hill, Thomas J.

    1982-01-01

    The report is a reference source on hydrologic information related to coal-mining activities in the Warrior and Plateau coal fields of Alabama. It contains a bibliography of more than 200 references and selected annotations. Also included is information on maps, automated-data bases, water-monitoring programs, and data-source agencies and organizations.

  20. Short-Term Oxidation Studies on Nicrofer- 6025HT in Air at Elevated Temperatures for Advanced Coal Based Power Plants

    SciTech Connect

    Joshi, Vineet V.; Meier, Alan; Darsell, Jens T.; Nachimuthu, Ponnusamy; Bowden, Mark E.; Weil, K. Scott

    2013-04-01

    Several advanced air separation unit (ASU) designs being considered for use in coal gasification rely on the use of solid state mixed ionic and electronic conductors. Nicrofer-6025HT, a nickel-based alloy, has been identified as a potential manifold material to transport the hot gases into the ASUs. In the current study, isothermal oxidation tests were conducted on Nicrofer-6025HT in the temperature range of 700–900 °C for up to 24 h. The evolution of oxide scale was evaluated using SEM, XRD, and XPS. The composite surface oxide layer that formed consisted of an outer chromia-rich scale and an inner alumina scale. For the longer times at the higher temperatures evaluated, a NiCr2O4 spinel phase was located at the interface between the alumina and chromia. Based on the experimental results a four-step oxidation model was proposed.

  1. Arsenic remediation of drinking water using iron-oxide coated coal bottom ash

    SciTech Connect

    MATHIEU, JOHANNA L.; GADGIL, ASHOK J.; ADDY, SUSAN E.A.; KOWOLIK, KRISTIN

    2010-06-01

    We describe laboratory and field results of a novel arsenic removal adsorbent called 'Arsenic Removal Using Bottom Ash' (ARUBA). ARUBA is prepared by coating particles of coal bottom ash, a waste material from coal fired power plants, with iron (hydr)oxide. The coating process is simple and conducted at room temperature and atmospheric pressure. Material costs for ARUBA are estimated to be low (~;;$0.08 per kg) and arsenic remediation with ARUBA has the potential to be affordable to resource-constrained communities. ARUBA is used for removing arsenic via a dispersal-and-removal process, and we envision that ARUBA would be used in community-scale water treatment centers. We show that ARUBA is able to reduce arsenic concentrations in contaminated Bangladesh groundwater to below the Bangladesh standard of 50 ppb. Using the Langmuir isotherm (R2 = 0.77) ARUBA's adsorption capacity in treating real groundwater is 2.6x10-6 mol/g (0.20 mg/g). Time-to-90percent (defined as the time interval for ARUBA to remove 90percent of the total amount of arsenic that is removed at equilibrium) is less than one hour. Reaction rates (pseudo-second-order kinetic model, R2>_ 0.99) increase from 2.4x105 to 7.2x105 g mol-1 min-1 as the groundwater arsenic concentration decreases from 560 to 170 ppb. We show that ARUBA's arsenic adsorption density (AAD), defined as the milligrams of arsenic removed at equilibrium per gram of ARUBA added, is linearly dependent on the initial arsenic concentration of the groundwater sample, for initial arsenic concentrations of up to 1600 ppb and an ARUBA dose of 4.0 g/L. This makes it easy to determine the amount of ARUBA required to treat a groundwater source when its arsenic concentration is known and less than 1600 ppb. Storing contaminated groundwater for two to three days before treatment is seen to significantly increase ARUBA's AAD. ARUBA can be separated from treated water by coagulation and clarification, which is expected to be less expensive than

  2. Arsenic remediation of drinking water using iron-oxide coated coal bottom ash.

    PubMed

    Mathieu, Johanna L; Gadgil, Ashok J; Addy, Susan E A; Kowolik, Kristin

    2010-09-01

    We describe laboratory and field results of a novel arsenic removal adsorbent called 'Arsenic Removal Using Bottom Ash' (ARUBA). ARUBA is prepared by coating particles of coal bottom ash, a waste material from coal fired power plants, with iron (hydr)oxide. The coating process is simple and conducted at room temperature and atmospheric pressure. Material costs for ARUBA are estimated to be low (approximately $0.08 per kg) and arsenic remediation with ARUBA has the potential to be affordable to resource-constrained communities. ARUBA is used for removing arsenic via a dispersal-and-removal process, and we envision that ARUBA would be used in community-scale water treatment centers. We show that ARUBA is able to reduce arsenic concentrations in contaminated Bangladesh groundwater to below the Bangladesh standard of 50 ppb. Using the Langmuir isotherm (R(2) = 0.77) ARUBA's adsorption capacity in treating real groundwater is 2.6 x 10(- 6)mol/g (0.20 mg/g). Time-to-90% (defined as the time interval for ARUBA to remove 90% of the total amount of arsenic that is removed at equilibrium) is less than 1 hour. Reaction rates (pseudo-second-order kinetic model, R(2) > or = 0.99) increase from 2.4 x 10(5) to 7.2 x 10(5) g mol(- 1)min(- 1) as the groundwater arsenic concentration decreases from 560 to 170 ppb. We show that ARUBA's arsenic adsorption density (AAD), defined as the milligrams of arsenic removed at equilibrium per gram of ARUBA added, is linearly dependent on the initial arsenic concentration of the groundwater sample, for initial arsenic concentrations of up to 1600 ppb and an ARUBA dose of 4.0 g/L. This makes it easy to determine the amount of ARUBA required to treat a groundwater source when its arsenic concentration is known and less than 1600 ppb. Storing contaminated groundwater for two to three days before treatment is seen to significantly increase ARUBA's AAD. ARUBA can be separated from treated water by coagulation and clarification, which is expected to

  3. Layer Control of WSe2 via Selective Surface Layer Oxidation.

    PubMed

    Li, Zhen; Yang, Sisi; Dhall, Rohan; Kosmowska, Ewa; Shi, Haotian; Chatzakis, Ioannis; Cronin, Stephen B

    2016-07-26

    We report Raman and photoluminescence spectra of mono- and few-layer WSe2 and MoSe2 taken before and after exposure to a remote oxygen plasma. For bilayer and trilayer WSe2, we observe an increase in the photoluminescence intensity and a blue shift of the photoluminescence peak positions after oxygen plasma treatment. The photoluminescence spectra of trilayer WSe2 exhibit features of a bilayer after oxygen plasma treatment. Bilayer WSe2 exhibits features of a monolayer, and the photoluminescence of monolayer WSe2 is completely absent after the oxygen plasma treatment. These changes are observed consistently in more than 20 flakes. The mechanism of the changes observed in the photoluminescence spectra of WSe2 is due to the selective oxidation of the topmost layer. As a result, N-layer WSe2 is reduced to N-1 layers. Raman spectra and AFM images taken from the WSe2 flakes before and after the oxygen treatment corroborate these findings. Because of the low kinetic energy of the oxygen radicals in the remote oxygen plasma, the oxidation is self-limiting. By varying the process duration from 1 to 10 min, we confirmed that the oxidation will only affect the topmost layer of the WSe2 flakes. X-ray photoelectron spectroscopy shows that the surface layer WOx of the sample can be removed by a quick dip in KOH solution. Therefore, this technique provides a promising way of controlling the thickness of WSe2 layer by layer. PMID:27391161

  4. Selective oxidation of bromide in wastewater brines from hydraulic fracturing.

    PubMed

    Sun, Mei; Lowry, Gregory V; Gregory, Kelvin B

    2013-07-01

    Brines generated from oil and natural gas production, including flowback water and produced water from hydraulic fracturing of shale gas, may contain elevated concentrations of bromide (~1 g/L). Bromide is a broad concern due to the potential for forming brominated disinfection byproducts (DBPs) during drinking water treatment. Conventional treatment processes for bromide removal is costly and not specific. Selective bromide removal is technically challenging due to the presence of other ions in the brine, especially chloride as high as 30-200 g/L. This study evaluates the ability of solid graphite electrodes to selectively oxidize bromide to bromine in flowback water and produced water from a shale gas operation in Southwestern PA. The bromine can then be outgassed from the solution and recovered, as a process well understood in the bromine industry. This study revealed that bromide may be selectively and rapidly removed from oil and gas brines (~10 h(-1) m(-2) for produced water and ~60 h(-1) m(-2) for flowback water). The electrolysis occurs with a current efficiency between 60 and 90%, and the estimated energy cost is ~6 kJ/g Br. These data are similar to those for the chlor-alkali process that is commonly used for chlorine gas and sodium hydroxide production. The results demonstrate that bromide may be selectively removed from oil and gas brines to create an opportunity for environmental protection and resource recovery.

  5. Selective oxidation of cyclohexene through gold functionalized silica monolith microreactors

    NASA Astrophysics Data System (ADS)

    Alotaibi, Mohammed T.; Taylor, Martin J.; Liu, Dan; Beaumont, Simon K.; Kyriakou, Georgios

    2016-04-01

    Two simple, reproducible methods of preparing evenly distributed Au nanoparticle containing mesoporous silica monoliths are investigated. These Au nanoparticle containing monoliths are subsequently investigated as flow reactors for the selective oxidation of cyclohexene. In the first strategy, the silica monolith was directly impregnated with Au nanoparticles during the formation of the monolith. The second approach was to pre-functionalize the monolith with thiol groups tethered within the silica mesostructure. These can act as evenly distributed anchors for the Au nanoparticles to be incorporated by flowing a Au nanoparticle solution through the thiol functionalized monolith. Both methods led to successfully achieving even distribution of Au nanoparticles along the length of the monolith as demonstrated by ICP-OES. However, the impregnation method led to strong agglomeration of the Au nanoparticles during subsequent heating steps while the thiol anchoring procedure maintained the nanoparticles in the range of 6.8 ± 1.4 nm. Both Au nanoparticle containing monoliths as well as samples with no Au incorporated were tested for the selective oxidation of cyclohexene under constant flow at 30 °C. The Au free materials were found to be catalytically inactive with Au being the minimum necessary requirement for the reaction to proceed. The impregnated Au-containing monolith was found to be less active than the thiol functionalized Au-containing material, attributable to the low metal surface area of the Au nanoparticles. The reaction on the thiol functionalized Au-containing monolith was found to depend strongly on the type of oxidant used: tert-butyl hydroperoxide (TBHP) was more active than H2O2, likely due to the thiol induced hydrophobicity in the monolith.

  6. Evaluation of Suitability of Selected Set of Coal Plant Sites for Repowering with Small Modular Reactors

    SciTech Connect

    Belles, Randy; Copinger, Donald A; Mays, Gary T; Omitaomu, Olufemi A; Poore III, Willis P

    2013-03-01

    This report summarizes the approach that ORNL developed for screening a sample set of small coal stations for possible repowering with SMRs; the methodology employed, including spatial modeling; and initial results for these sample plants. The objective in conducting this type of siting evaluation is to demonstrate the capability to characterize specific sample coal plant sites to identify any particular issues associated with repowering existing coal stations with SMRs using OR-SAGE; it is not intended to be a definitive assessment per se as to the absolute suitability of any particular site.

  7. Co-Al mixed metal oxides/carbon nanotubes nanocomposite prepared via a precursor route and enhanced catalytic property

    NASA Astrophysics Data System (ADS)

    Fan, Guoli; Wang, Hui; Xiang, Xu; Li, Feng

    2013-01-01

    The present work reported the synthesis of Co-Al mixed metal oxides/carbon nanotubes (CoAl-MMO/CNT) nanocomposite from Co-Al layered double hydroxide/CNTs composite precursor (CoAl-LDH/CNT). The materials were characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM), low temperature nitrogen adsorption-desorption experiments, thermogravimetric and differential thermal analyses (TG-DTA), Raman spectra and X-ray photoelectron spectroscopy (XPS). The results revealed that in CoAl-MMO/CNT nanocomposite, the nanoparticles of cobalt oxide (CoO) and Co-containing spinel-type complex metal oxides could be well-dispersed on the surface of CNTs, thus forming the heterostructure of CoAl-MMO and CNTs. Furthermore, as-synthesized CoAl-MMO/CNT nanocomposite was utilized as additives for catalytic thermal decomposition of ammonium perchlorate (AP). Compared to those for pure AP and CoAl-MMO, the peak temperature of AP decomposition for CoAl-MMO/CNT was significantly decreased, which is attributed to the novel heterostructure and synergistic effect of multi-component metal oxides of nanocomposite.

  8. Microbial, algal, and fungal strategies for manganese oxidation at a Shade Township coal mine, Somerset County, Pennsylvania

    SciTech Connect

    Robbins, E.I.; Brant, D.L.; Ziemkiewicz, P.F.

    1999-07-01

    Successful designs to eliminate Mn from mine discharge are necessary for both restoring abandoned mine lands and permitting the mining of high sulfur coal in the eastern United States. A passive in-line system that meets Mn discharge limits was built at the discharge from the former Shade Township coal mine in south central Pennsylvania. Qualitative research on monthly changes in the microbial and algal community that removes Mn is underway. Epilithic attachment of microorganisms was analyzed on artificial (glass microscope slides) and natural substrates (limestone thin sections) that were immersed in surface water for one month periods over 6 months. Organisms attached to both glass and limestone substrates. Limestone became coated with 34--86% more Mn that did glass surfaces. Light microscopy revealed 12 different strategies are being used by bacteria, cyan bacteria, diatoms, green algae, and fungi to oxidize Mn. the dominant method used by the epilithic community to oxidize Mn is coating of holdfasts by the iron bacterium, Liptothrix discophora, and the green alga, Ulothrix sp. Other methods for Mn removal by oxidation include coating of individual cells, filaments/sheaths/hyphae, extracellular polysaccharides, and biofilms. The unplanned community at the site is multifaceted and extremely efficient in its Mn removal ability. Community interactions or complexity may play roles in the stability of the ecosystem and the efficiency of its Mn oxidizing ability.

  9. Highly Selective H2 Separation Zeolite Membranes for Coal Gasification Membrane Reactor Applications

    SciTech Connect

    Mei Hong; Richard D. Noble; John L. Falconer

    2006-09-24

    Zeolite membranes are thermally, chemically, and mechanically stable. They also have tunable molecular sieving and catalytic ability. These unique properties make zeolite membrane an excellent candidate for use in catalytic membrane reactor applications related to coal conversion and gasification, which need high temperature and high pressure range separation in chemically challenging environment where existing technologies are inefficient or unable to operate. Small pore, good quality, and thin zeolite membranes are needed for highly selective H{sub 2} separation from other light gases (CO{sub 2}, CH{sub 4}, CO). However, zeolite membranes have not been successful for H{sub 2} separation from light gases because the zeolite pores are either too big or the membranes have a large number of defects. The objective of this study is to develop zeolite membranes that are more suitable for H{sub 2} separation. In an effort to tune the size of zeolite pores and/or to decrease the number of defects, medium-pore zeolite B-ZSM-5 (MFI) membranes were synthesized and silylated. Silylation on B-ZSM-5 crystals reduced MFI-zeolite pore volume, but had little effect on CO{sub 2} and CH{sub 4} adsorption. Silylation on B-ZSM-5 membranes increased H{sub 2} selectivity both in single component and in mixtures with CO{sub 2}CO{sub 2}, CH{sub 4}, or N2. Single gas and binary mixtures of H{sub 2}/CO{sub 2} and H{sub 2}/CH{sub 4} were separated through silylated B-ZSM-5 membranes at feed pressures up to 1.7 MPa and temperatures up to 773 K. For one BZSM-5 membrane after silylation, the H2/CO{sub 2} separation selectivity at 473 K increased from 1.4 to 37, whereas the H{sub 2}/CH{sub 4} separation selectivity increased from 1.6 to 33. Hydrogen permeance through a silylated B-ZSM-5 membrane was activated, but the CO{sub 2} and CH4 permeances decreased slightly with temperature in both single gas and in mixtures. Therefore, the H{sub 2} permeance and H{sub 2}/CO{sub 2} and H{sup 2} /CH{sub 4

  10. Phase discrimination through oxidant selection in low-temperature atomic layer deposition of crystalline iron oxides.

    PubMed

    Riha, Shannon C; Racowski, Joy M; Lanci, Michael P; Klug, Jeffrey A; Hock, Adam S; Martinson, Alex B F

    2013-03-12

    Control over the oxidation state and crystalline phase of thin-film iron oxides was achieved by low-temperature atomic layer deposition (ALD), utilizing a novel iron precursor, bis(2,4-methylpentadienyl)iron. This low-temperature (T = 120 °C) route to conformal deposition of crystalline Fe3O4 or α-Fe2O3 thin films is determined by the choice of oxygen source selected for the second surface half-reaction. The approach employs ozone to produce fully oxidized α-Fe2O3 or a milder oxidant, H2O2, to generate the Fe(2+)/Fe(3+) spinel, Fe3O4. Both processes show self-limiting surface reactions and deposition rates of at least 0.6 Å/cycle, a significantly high growth rate at such mild conditions. We utilized this process to prepare conformal iron oxide thin films on a porous framework, for which α-Fe2O3 is active for photocatalytic water splitting.

  11. Selective solvent absorption in coal conversion. Quarterly report, April 1, 1992--June 30, 1992

    SciTech Connect

    Larsen, J.W.; Amui, J.

    1992-06-01

    The objectives of this research are: (1) to determine the importance of the presence of added hydrogen donor compounds within the coal in the first stage of direct liquefaction processes; and (2) to determine the composition of the solvent absorbed by and present within the coal in the first stages of direct coal liquefaction. Scope of work study the conversion of Argonne Premium coals in tetralin and 2-t-butyltetralin and compare the following: conversion to soluble products and product composition. Hydrogen donated by both solvents will be measured by gas chromatography and the same technique will be used to establish the amount of dealkylation of 2-t-butyltetralin. Reactions will be performed at several different temperatures for varying amounts of time.

  12. Selective solvent absorption in coal conversion. Quarterly report, July 1, 1992--September 30, 1992

    SciTech Connect

    Larsen, J.W.; Amui, J.

    1992-12-31

    The objectives of this program include: Determine the importance of the presence of added hydrogen donor compounds within the coal in the first stage of direct liquefaction processes; and to determine the composition of the solvent absorbed by and present within the coal in the first stages of direct coal liquefaction. The scope includes the study of the conversion of Argonne Premium coals in tetralin and 2-t-butyltetralin and a comparison of the following: Conversion to soluble products and product composition. Hydrogen donated by both solvents will be measured by gas chromatography and the same technique will be used to establish the amount of dealkylation of 2-t-butyltetralin. Reactions will be performed at several different temperatures for varying amounts of time.

  13. Selective oxidation of methanol and ethanol on supported ruthenium oxide clusters at low temperatures.

    PubMed

    Liu, Haichao; Iglesia, Enrique

    2005-02-17

    RuO2 domains supported on SnO2, ZrO2, TiO2, Al2O3, and SiO2 catalyze the oxidative conversion of methanol to formaldehyde, methylformate, and dimethoxymethane with unprecedented rates and high combined selectivity (>99%) and yield at low temperatures (300-400 K). Supports influence turnover rates and the ability of RuO2 domains to undergo redox cycles required for oxidation turnovers. Oxidative dehydrogenation turnover rates and rates of stoichiometric reduction of RuO2 in H2 increased in parallel when RuO2 domains were dispersed on more reducible supports. These support effects, the kinetic effects of CH3OH and O2 on reaction rates, and the observed kinetic isotope effects with CH3OD and CD3OD reactants are consistent with a sequence of elementary steps involving kinetically relevant H-abstraction from adsorbed methoxide species using lattice oxygen atoms and with methoxide formation in quasi-equilibrated CH3OH dissociation on nearly stoichiometric RuO2 surfaces. Anaerobic transient experiments confirmed that CH3OH oxidation to HCHO requires lattice oxygen atoms and that selectivities are not influenced by the presence of O2. Residence time effects on selectivity indicate that secondary HCHO-CH3OH acetalization reactions lead to hemiacetal or methoxymethanol intermediates that convert to dimethoxymethane in reactions with CH3OH on support acid sites or dehydrogenate to form methylformate on RuO2 and support redox sites. These conclusions are consistent with the tendency of Al2O3 and SiO2 supports to favor dimethoxymethane formation, while SnO2, ZrO2, and TiO2 preferentially form methylformate. These support effects on secondary reactions were confirmed by measured CH3OH oxidation rates and selectivities on physical mixtures of supported RuO2 catalysts and pure supports. Ethanol also reacts on supported RuO2 domains to form predominately acetaldehyde and diethoxyethane at 300-400 K. The bifunctional nature of these reaction pathways and the remarkable ability of Ru

  14. Selective oxidation of methanol and ethanol on supported ruthenium oxide clusters at low temperatures

    SciTech Connect

    Liu, Haichao; Iglesia, Enrique

    2004-03-04

    RuO2 domains supported on SnO2, ZrO2, TiO2, Al2O3, and SiO2 catalyze the oxidative conversion of methanol to formaldehyde, methylformate, and dimethoxymethane with unprecedented rates and high combined selectivity (>99 percent) and yield at low temperatures (300-400 K). Supports influence turnover rates and the ability of RuO2 domains to undergo redox cycles required for oxidation turnovers. Oxidative dehydrogenation turnover rates and rates of stoichiometric reduction of RuO2 in H2 increased in parallel when RuO2 domains were dispersed on more reducible supports. These support effects, the kinetic effects of CH3OH and O2 on reaction rates, and the observed kinetic isotope effects with CH3OD and CD3OD reactants are consistent with a sequence of elementary steps involving kinetically relevant H-abstraction from adsorbed methoxide species using lattice oxygen atoms and with methoxide formation in quasi-equilibrated CH3OH dissociation on nearly stoichiometric RuO2 surfaces. Anaerobic transient experiments confirmed that CH3OH oxidation to HCHO requires lattice oxygen atoms and that selectivities are not influenced by the presence of O2. Residence time effects on selectivity indicate that secondary HCHO-CH3OH acetalization reactions lead to hemiacetal or methoxymethanol intermediates that convert to dimethoxymethane in reactions with CH3OH on support acid sites or dehydrogenate to form methylformate on RuO2 and support redox sites. These conclusions are consistent with the tendency of Al2O3 and SiO2 supports to favor dimethoxymethane formation, while SnO2, ZrO2, and TiO2 preferentially form methylformate. These support effects on secondary reactions were confirmed by measured CH3OH oxidation rates and selectivities on physical mixtures of supported RuO2 catalysts and pure supports. Ethanol also reacts on supported RuO2 domains to form predominately acetaldehyde and diethoxyethane at 300-400 K. The bifunctional nature of these reaction pathways and the remarkable

  15. Enzymatic desulfurization of coal

    SciTech Connect

    Boyer, Y.N.; Crooker, S.C.; Kitchell, J.P.; Nochur, S.V. ); Marquis, J.K. . School of Medicine)

    1989-11-07

    Our experimental approach focuses on the use of enzymes which catalyze the addition of oxygen to organic compounds. In tailoring the application of these enzymes to coal processing, we are particularly interested in ensuring that oxidation occurs at sulfur and not at carbon-carbon bonds. Previous studies with DBT have shown that the reaction most frequently observed in microbial oxidative pathways is one in which DBT is oxidized at ring carbons. These reactions, as we have said, are accompanied by a considerable decrease in the energy content of the compound. In addition, microbial pathways have been identified in which the sulfur atom is sequentially oxidized to sulfoxide, to sulfone, to sulfonate, and finally to sulfuric acid. In this case, the fuel value of the desulfurized compounds is largely retained. We are evaluating the potential of commercially available enzymes to selectively catalyze oxidation at sulfur.

  16. Elucidating the mechanism of Cr(VI) formation upon the interaction with metal oxides during coal oxy-fuel combustion.

    PubMed

    Chen, Juan; Jiao, Facun; Zhang, Lian; Yao, Hong; Ninomiya, Yoshihiko

    2013-10-15

    The thermodynamics underpinning the interaction of Cr-bearing species with basic metal oxides, i.e. K2O, Fe2O3, MgO and CaO, during the air and oxy-fuel combustion of coal have been examined. The synchrotron-based X-ray adsorption near-edge spectroscopy (XANES) was used for Cr speciation. For the oxides tested, Cr(VI) formation is dominated by the reduction potential of the metals. The oxides of Ca(2+) with high reduction potential favored the oxidation of Cr(III), same for K(+). The other two basic metals, Fe2O3 and MgO with lower reduction potentials reacted with Cr(III) to form the corresponding chromites at the temperatures above 600°C. Coal combustion experiments in drop-tube furnace have confirmed the rapid capture of Cr vapors, either trivalent or hexavalent, by CaO into solid ash. The existence of HCl in flue gas favored the vaporization of Cr as CrO2Cl2, which was in turn captured by CaO into chromate. Both Fe2O3 and MgO exhibited less capability on scavenging the Cr(VI) vapor. Particularly, MgO alone exhibited a low capability for capturing the vaporized Cr(III) vapors. However, its co-existence with CaO in the furnace inhibited the Cr(VI) formation. This is beneficial for minimizing the toxicity of Cr in the coal combustion-derived fly ash. PMID:23969010

  17. Magneto-transport properties of oriented Mn{sub 2}CoAl films sputtered on thermally oxidized Si substrates

    SciTech Connect

    Xu, G. Z.; Du, Y.; Zhang, X. M.; Liu, E. K.; Wang, W. H. Wu, G. H.; Zhang, H. G.

    2014-06-16

    Spin gapless semiconductors are interesting family of materials by embracing both magnetism and semiconducting due to their unique band structure. Its potential application in future spintronics requires realization in thin film form. In this Letter, we report fabrication and transport properties of spin gapless Mn{sub 2}CoAl films prepared on thermally oxidized Si substrates by magnetron sputtering deposition. The films deposited at 673 K are well oriented to (001) direction and display a uniform-crystalline surface. Magnetotransport measurements on the oriented films reveal a semiconducting-like resistivity, small anomalous Hall conductivity, and linear magnetoresistance representative of the transport signatures of spin gapless semiconductors. The magnetic properties of the films have also been investigated and compared to that of bulk Mn{sub 2}CoAl, showing small discrepancy induced by the composition deviation.

  18. Interaction of coal-derived synthesis gas impurities with solid oxide fuel cell metallic components

    NASA Astrophysics Data System (ADS)

    Marina, Olga A.; Pederson, Larry R.; Coyle, Christopher A.; Edwards, Danny J.; Chou, Yeong-Shyung; Cramer, Carolyn N.

    Oxidation-resistant alloys find use as interconnect materials, heat exchangers, and gas supply tubing in solid oxide fuel cell (SOFC) systems, especially when operated at temperatures below ∼800 °C. If fueled with synthesis gas derived from coal or biomass, such metallic components could be exposed to impurities contained in those fuel sources. In this study, coupons of ferritic stainless steels Crofer 22 APU and SS 441, austenitic nickel-chromium superalloy Inconel 600, and an alumina-forming high nickel alloy alumel were exposed to synthesis gas containing ≤2 ppm phosphorus, arsenic and antimony, and reaction products were tested. Crofer 22 APU coupons coated with a (Mn,Co) 3O 4 protective layer were also evaluated. Phosphorus was found to be the most reactive. On Crofer 22 APU, the (Mn,Cr) 3O 4 passivation layer reacted to form an Mn-P-O product, predicted to be manganese phosphate from thermochemical calculations, and Cr 2O 3. On SS 441, reaction of phosphorus with (Mn,Cr) 3O 4 led to the formation of manganese phosphate as well as an Fe-P product, predicted from thermochemical calculations to be Fe 3P. Minimal interactions with antimony or arsenic in synthesis gas were limited to Fe-Sb and Fe-As solid solution formation. Though not intended for use on the anode side, a (Mn,Co) 3O 4 spinel coating on Crofer 22 APU reacted with phosphorus in synthesis gas to produce products consistent with Mn 3(PO 4) 2 and Co 2P. A thin Cr 2O 3 passivation layer on Inconel 600 did not prevent the formation of nickel phosphides and arsenides and of iron phosphides and arsenides, though no reaction with Cr 2O 3 was apparent. On alumel, an Al 2O 3 passivation layer rich in Ni did not prevent the formation of nickel phosphides, arsenides, and antimonides, though no reaction with Al 2O 3 occurred. This work shows that unprotected metallic components of an SOFC stack and system can provide a sink for P, As and Sb impurities that may be present in fuel gases, and thus complicate

  19. N sub 2 O formation from advanced NO sub x control processes (selective non-catalytic reduction and coal reburning)

    SciTech Connect

    Montgomery, T.A.; Martz, T.D.; Quartucy, G.C.; Muzio, L.J. ); Sheldon, M.S.; Cole, J.A.; Kramlich, J.C. ); Samuelsen, G.S.; Reddy, V. )

    1991-04-01

    The current work addressed the potential of N{sub 2}O production from two NO{sub x} reduction techniques: selective non-catalytic NO{sub x} reduction (SNCR processes) and reburning with pulverized coal. The effects of SNCR processes (utilizing ammonia, urea, and cyanuric acid injection) and reburning processes (with bituminous and lignite coals) upon NO{sub x} and N{sub 2}O levels were evaluated. Pilot scale testing and chemical kinetic modeling were used to characterize the N{sub 2} production from SNCR processes over a range of process parameters. The data show that the evaluated SNCR processes (ammonia, urea, and cyanuric acid injection) produced some N{sub 2}O as a by-product. Ammonia injection produced the lowest levels of N{sub 2}O; less than 4% of the reduced NO{sub x} was converted to N{sub 2}O. Cyanuric acid injection produced the highest levels; N{sub 2}O increases ranged between 12--40% of the reduced NO{sub x}. The conversion of NO{sub x} to N{sub 2}O with urea injection ranged from 7--25%. Pilot scale testing was used to characterize the N{sub 2}O production from reburning processes with coal over a range of process parameters. Parameters included: coal type, firing rate, initial NO level, and reburn zone stoichiometry. Data show that N{sub 2}O is not a major product during coal reburning processes for NO{sub x} reduction. 56 figs., 13 tabs.

  20. Development of a Solid Oxide Fuel Cell for the utilization of coal mine gas

    NASA Astrophysics Data System (ADS)

    Groß, B.; Blum, L.; de Haart, L. G. J.; Dengel, A.

    Apart from natural gas there is another important natural source of methane. The so-called coal mine gas is a by-product of the geochemical process of the carbonization of sediments from marsh woods of the Earth's Carboniferous Period. Methane evaporates from the coal and has to be removed out of the active mines where it represents one of the main safety risks. Methane also evaporates in abandoned coal mines. In the federal state Saarland in Germany exists above ground a more than 110 km pipeline for the drained coal mine gas from 12 different sources. The content of methane varies between 25 and 90%, the oxygen content (from air) is in the range up to 10%. This wide range or variation, respectively, of fuel and oxygen content, causes a lot of problems for the use in conventional engines. Therefore the company Evonik New Energies GmbH is interested in using SOFC with coal mine gas as efficient as possible to produce electric power. For that purpose at Forschungszentrum Jülich the available SOFC technology was adapted to the use with coal mine gas and a test facility was designed to operate an SOFC stack (approximately 2 kW electrical power output) together with a pre-reformer. This paper presents the results of the coal mine gas analysis and the effect on the pre-reformer and the fuel cell. The composition of the coal mine gas was determined by means of micro-gas chromatography. The results obtained from preliminary tests using synthetic and real coal mine gas on the pre-reformer and on the fuel cell are discussed.

  1. Materials selection for oxide-based resistive random access memories

    SciTech Connect

    Guo, Yuzheng; Robertson, John

    2014-12-01

    The energies of atomic processes in resistive random access memories (RRAMs) are calculated for four typical oxides, HfO{sub 2}, TiO{sub 2}, Ta{sub 2}O{sub 5}, and Al{sub 2}O{sub 3}, to define a materials selection process. O vacancies have the lowest defect formation energy in the O-poor limit and dominate the processes. A band diagram defines the operating Fermi energy and O chemical potential range. It is shown how the scavenger metal can be used to vary the O vacancy formation energy, via controlling the O chemical potential, and the mean Fermi energy. The high endurance of Ta{sub 2}O{sub 5} RRAM is related to its more stable amorphous phase and the adaptive lattice rearrangements of its O vacancy.

  2. Quinone-Catalyzed Selective Oxidation of Organic Molecules.

    PubMed

    Wendlandt, Alison E; Stahl, Shannon S

    2015-12-01

    Quinones are common stoichiometric reagents in organic chemistry. Para-quinones with high reduction potentials, such as DDQ and chloranil, are widely used and typically promote hydride abstraction. In recent years, many catalytic applications of these methods have been achieved by using transition metals, electrochemistry, or O2 to regenerate the oxidized quinone in situ. Complementary studies have led to the development of a different class of quinones that resemble the ortho-quinone cofactors in copper amine oxidases and mediate the efficient and selective aerobic and/or electrochemical dehydrogenation of amines. The latter reactions typically proceed by electrophilic transamination and/or addition-elimination reaction mechanisms, rather than hydride abstraction pathways. The collective observations show that the quinone structure has a significant influence on the reaction mechanism and has important implications for the development of new quinone reagents and quinone-catalyzed transformations. PMID:26530485

  3. Increased Oxidative Stress as a Selective Anticancer Therapy

    PubMed Central

    Liu, Jiahui; Wang, Zhichong

    2015-01-01

    Reactive oxygen species (ROS) are closely related to tumorgenesis. Under hypoxic environment, increased levels of ROS induce the expression of hypoxia inducible factors (HIFs) in cancer stem cells (CSCs), resulting in the promotion of the upregulation of CSC markers, and the reduction of intracellular ROS level, thus facilitating CSCs survival and proliferation. Although the ROS level is regulated by powerful antioxidant defense mechanisms in cancer cells, it is observed to remain higher than that in normal cells. Cancer cells may be more sensitive than normal cells to the accumulation of ROS; consequently, it is supposed that increased oxidative stress by exogenous ROS generation therapy has an effect on selectively killing cancer cells without affecting normal cells. This paper reviews the mechanisms of redox regulation in CSCs and the pivotal role of ROS in anticancer treatment. PMID:26273420

  4. Nanorecycling: Monolithic Integration of Copper and Copper Oxide Nanowire Network Electrode through Selective Reversible Photothermochemical Reduction.

    PubMed

    Han, Seungyong; Hong, Sukjoon; Yeo, Junyeob; Kim, Dongkwan; Kang, Bongchul; Yang, Min-Yang; Ko, Seung Hwan

    2015-11-01

    Laser induced selective photothermochemical reduction is demonstrated to locally and reversibly control the oxidation state of Cu and Cu oxide nanowires in ambient conditions without any inert gas environment. This new concept of "nanorecycling" can monolithically integrate Cu and Cu oxide nanowires by restoring oxidized Cu, considered unusable for the electrode, back to a metallic state for repetitive reuse.

  5. Process for removing sulfur from coal

    DOEpatents

    Aida, Tetsuo; Squires, Thomas G.; Venier, Clifford G.

    1985-02-05

    A process for the removal of divalent organic and inorganic sulfur compounds from coal and other carbonaceous material. A slurry of pulverized carbonaceous material is contacted with an electrophilic oxidant which selectively oxidizes the divalent organic and inorganic compounds to trivalent and tetravalent compounds. The carbonaceous material is then contacted with a molten caustic which dissolves the oxidized sulfur compounds away from the hydrocarbon matrix.

  6. Process for removing sulfur from coal

    DOEpatents

    Aida, T.; Squires, T.G.; Venier, C.G.

    1983-08-11

    A process is disclosed for the removal of divalent organic and inorganic sulfur compounds from coal and other carbonaceous material. A slurry of pulverized carbonaceous material is contacted with an electrophilic oxidant which selectively oxidizes the divalent organic and inorganic compounds to trivalent and tetravalent compounds. The carbonaceous material is then contacted with a molten caustic which dissolves the oxidized sulfur compounds away from the hydrocarbon matrix.

  7. Selective stabilization of aliphatic organic carbon by iron oxide

    PubMed Central

    Adhikari, Dinesh; Yang, Yu

    2015-01-01

    Stabilization of organic matter in soil is important for natural ecosystem to sequestrate carbon and mitigate greenhouse gas emission. It is largely unknown what factors govern the preservation of organic carbon in soil, casting shadow on predicting the response of soil to climate change. Iron oxide was suggested as an important mineral preserving soil organic carbon. However, ferric minerals are subject to reduction, potentially releasing iron and decreasing the stability of iron-bound organic carbon. Information about the stability of iron-bound organic carbon in the redox reaction is limited. Herein, we investigated the sorptive interactions of organic matter with hematite and reductive release of hematite-bound organic matter. Impacts of organic matter composition and conformation on its sorption by hematite and release during the reduction reaction were analyzed. We found that hematite-bound aliphatic carbon was more resistant to reduction release, although hematite preferred to sorb more aromatic carbon. Resistance to reductive release represents a new mechanism that aliphatic soil organic matter was stabilized by association with iron oxide. Selective stabilization of aliphatic over aromatic carbon can greatly contribute to the widely observed accumulation of aliphatic carbon in soil, which cannot be explained by sorptive interactions between minerals and organic matter. PMID:26061259

  8. Selective stabilization of aliphatic organic carbon by iron oxide.

    PubMed

    Adhikari, Dinesh; Yang, Yu

    2015-01-01

    Stabilization of organic matter in soil is important for natural ecosystem to sequestrate carbon and mitigate greenhouse gas emission. It is largely unknown what factors govern the preservation of organic carbon in soil, casting shadow on predicting the response of soil to climate change. Iron oxide was suggested as an important mineral preserving soil organic carbon. However, ferric minerals are subject to reduction, potentially releasing iron and decreasing the stability of iron-bound organic carbon. Information about the stability of iron-bound organic carbon in the redox reaction is limited. Herein, we investigated the sorptive interactions of organic matter with hematite and reductive release of hematite-bound organic matter. Impacts of organic matter composition and conformation on its sorption by hematite and release during the reduction reaction were analyzed. We found that hematite-bound aliphatic carbon was more resistant to reduction release, although hematite preferred to sorb more aromatic carbon. Resistance to reductive release represents a new mechanism that aliphatic soil organic matter was stabilized by association with iron oxide. Selective stabilization of aliphatic over aromatic carbon can greatly contribute to the widely observed accumulation of aliphatic carbon in soil, which cannot be explained by sorptive interactions between minerals and organic matter. PMID:26061259

  9. Selected attributes of polyphenols in targeting oxidative stress in cancer.

    PubMed

    Stepanic, Visnja; Gasparovic, Ana Cipak; Troselj, Koraljka Gall; Amic, Dragan; Zarkovic, Neven

    2015-01-01

    Various plant polyphenols have been recognized as redox active molecules. This review discusses some aspects of polyphenols' modes of redox action, corresponding structure-activity relationships and their potential to be applied as adjuvants to conventional cytostatic drugs. Polyphenols' antioxidative capacity has been discussed as the basis for targeting oxidative stress and, consequently, for their chemopreventive and anti-inflammatory activities, which may alleviate side-effects on normal cells arising from oxidative stress caused by cytostatics. Some polyphenols may scavenge various free radicals directly, and some of them are found to suppress free radical production through inhibiting NADPH oxidases and xanthine oxidase. Additionally, polyphenols may increase antioxidative defense in normal cells by increasing the activity of NRF2, transcription factor for many protective proteins. The activation of the NRF2-mediated signaling pathways in cancer cells results in chemoresistance. Luteolin, apigenin and chrysin reduce NRF2 expression and increase the chemosensitivity of cancer cells to cytostatic drugs. Their common 5,7-dihydroxy-4H-chromen-4-one moiety, may represent a starting pharmacophore model for designing novel, non-toxic compounds for overcoming chemoresistance. However, prooxidative activity of some polyphenols (quercetin, EGCG) may also provide a basis for their use as chemotherapeutic adjuvants since they may enhance cytotoxic effects of cytostatics selectively on cancer cells. However, considerable caution is needed in applying polyphenols to anticancer therapy, since their effects greatly depend on the applied dose, the cell type, exposure time and environmental conditions.

  10. Highly Selective H2 Separation Zeolite Membranes for Coal Gasification Membrane Reactor Applications

    SciTech Connect

    Mei Hong; Richard Noble; John Falconer

    2007-09-24

    Zeolite membranes are thermally, chemically, and mechanically stable. They also have tunable molecular sieving and catalytic ability. These unique properties make zeolite membrane an excellent candidate for use in catalytic membrane reactor applications related to coal conversion and gasification, which need high temperature and high pressure range separation in chemically challenging environment where existing technologies are inefficient or unable to operate. Small pore, good quality, and thin zeolite membranes are needed for highly selective H2 separation from other light gases (CO2, CH4, CO). However, current zeolite membranes have either too big zeolite pores or a large number of defects and have not been successful for H2 separation from light gases. The objective of this study is to develop zeolite membranes that are more suitable for H2 separation. In an effort to tune the size of zeolite pores and/or to decrease the number of defects, medium-pore zeolite B-ZSM-5 (MFI) membranes were synthesized and silylated. Silylation on B-ZSM-5 crystals reduced MFI-zeolite pore volume, but had little effect on CO2 and CH4 adsorption. Silylation on B-ZSM-5 membranes increased H2 selectivity both in single component and in mixtures with CO2, CH4, or N2. Single gas and binary mixtures of H2/CO2 and H2/CH4 were permeated through silylated B-ZSM-5 membranes at feed pressures up to 1.7 MPa and temperatures up to 773 K. For one B-ZSM-5 membrane after silylation, the H2/CO2 separation selectivity at 473 K increased from 1.4 to 37, whereas the H2/CH4 separation selectivity increased from 1.6 to 33. Hydrogen permeance through a silylated BZSM-5 membrane was activated with activation energy of {approx}10 kJ/mol, but the CO2 and CH4 permeances decreased slightly with temperature in both single gas and in mixtures. Therefore, the H2 permeance and H2/CO2 and H2/CH4 separation selectivities increased with temperature. At 673 K, the H2 permeance was 1.0x10-7 mol{center_dot}m-2{center

  11. Aerobic sulfur-oxidizing bacteria: Environmental selection and diversification

    NASA Technical Reports Server (NTRS)

    Caldwell, D.

    1985-01-01

    Sulfur-oxidizing bacteria oxidize reduced inorganic compounds to sulfuric acid. Lithotrophic sulfur oxidizer use the energy obtained from oxidation for microbial growth. Heterotrophic sulfur oxidizers obtain energy from the oxidation of organic compounds. In sulfur-oxidizing mixotrophs energy are derived either from the oxidation of inorganic or organic compounds. Sulfur-oxidizing bacteria are usually located within the sulfide/oxygen interfaces of springs, sediments, soil microenvironments, and the hypolimnion. Colonization of the interface is necessary since sulfide auto-oxidizes and because both oxygen and sulfide are needed for growth. The environmental stresses associated with the colonization of these interfaces resulted in the evolution of morphologically diverse and unique aerobic sulfur oxidizers.

  12. Studies of the fate of sulfur trioxide in coal-fired utility boilers based on modified selected condensation methods.

    PubMed

    Cao, Yan; Zhou, Hongcang; Jiang, Wu; Chen, Chien-Wei; Pan, Wei-Ping

    2010-05-01

    The formation of sulfur trioxide (SO(3)) in coal-fired utility boilers can have negative effects on boiler performance and operation, such as fouling and corrosion of equipment, efficiency loss in the air preheater (APH), increase in stack opacity, and the formation of PM(2.5). Sulfur trioxide can also compete with mercury when bonding with injected activated carbons. Tests in a lab-scale reactor confirmed there are major interferences between fly ash and SO(3) during SO(3) sampling. A modified SO(3) procedure to maximize the elimination of measurement biases, based on the inertial-filter-sampling and the selective-condensation-collecting of SO(3), was applied in SO(3) tests in three full-scale utility boilers. For the two units burning bituminous coal, SO(3) levels starting at 20 to 25 ppmv at the inlet to the selective catalytic reduction (SCR), increased slightly across the SCR, owing to catalytic conversion of SO(2) to SO(3,) and then declined in other air pollutant control device (APCD) modules downstream to approximately 5 ppmv and 15 ppmv at the two sites, respectively. In the unit burning sub-bituminous coal, the much lower initial concentration of SO(3) estimated to be approximately 1.5 ppmv at the inlet to the SCR was reduced to about 0.8 ppmv across the SCR and to about 0.3 ppmv at the exit of the wet flue gas desulfurization (WFGD). The SO(3) removal efficiency across the WFGD scrubbers at the three sites was generally 35% or less. Reductions in SO(3) across either the APH or the dry electrostatic precipitator (ESP) in units burning high-sulfur bituminous coal were attributed to operating temperatures being below the dew point of SO(3).

  13. Tunable Orbital-Selective Magnetic Interaction in Tricolor Oxide Interfaces

    NASA Astrophysics Data System (ADS)

    Cao, Yanwei; Kareev, Michael; Liu, Xiaoran; Choudhury, Debraj; Middey, Srimanta; Meyers, Derek; Chakhalian, Jak

    2015-03-01

    Recently, several theoretical scenarios of orbital-selective magnetic interactions were proposed to understand the emergence of the unexpected interfacial magnetism in the archetypical SrTiO3-based two-dimensional electron gas systems, the origin of which is still intriguing and not an entirely understood phenomenon in oxide interface physics. Experimentally, however, there thus far lacks a material system to directly demonstrate the magnetic interaction with orbital-selection (dxy vs. dxz/dyz) and eventually manipulate this magnetic interaction. To address this, here we induced 2DEG and localized magnetism into the same SrTiO3 layer by devising the heterostructure LaTiO3/SrTiO3/YTiO3. Combined electrical transport and atomic-resolved scanning transmission electron microscope with electron energy loss spectroscopy revealed that the magnetic localized electrons are formed by the spin transfer from the YTiO3 layer into 2DEG formed at the LaTiO3 /SrTiO3 interface, with the orbital occupancy and strength of the magnetic interaction controlled by the SrTiO3 layer thickness. Our work provides an ideal platform to explore the orbital physics driven by the interfacial magnetism with prospects for exciting spintronic applications.

  14. Influence of retardation caused by partially oxidized adsorbate upon the oxidation state of copper catalyst and its performance for selective propylene oxidation

    SciTech Connect

    Inui, T.; Ueda, T.; Suehiro, M.

    1980-09-01

    Propylene oxidation to acrolein on copper oxide catalyst was optimized at 300/sup 0/C, a 3.5:1 propylene-oxygen ratio, and a slightly reduced cuprous oxide catalyst of 2.17:1 copper-oxygen ratio. Increasing feed concentrations of both propylene and oxygen (in nitrogen) increased both conversion and selectivity for acrolein. The optimum oxidation state of the catalyst was obtained by starting with completely reduced copper; other initial oxidation states gave steady-state catalysts with higher oxidation states. High oxygen concentrations caused sintering and cupric oxide whisker growth.

  15. Promotion of Mn(II) Oxidation and Remediation of Coal Mine Drainage in Passive Treatment Systems by Diverse Fungal and Bacterial Communities ▿ †

    PubMed Central

    Santelli, Cara M.; Pfister, Donald H.; Lazarus, Dana; Sun, Lu; Burgos, William D.; Hansel, Colleen M.

    2010-01-01

    Biologically active, passive treatment systems are commonly employed for removing high concentrations of dissolved Mn(II) from coal mine drainage (CMD). Studies of microbial communities contributing to Mn attenuation through the oxidation of Mn(II) to sparingly soluble Mn(III/IV) oxide minerals, however, have been sparse to date. This study reveals a diverse community of Mn(II)-oxidizing fungi and bacteria existing in several CMD treatment systems. PMID:20495049

  16. Evaluation of the Impact of Chlorine on Mercury Oxidation in a Pilot-Scale Coal Combustor--The Effect of Coal Blending

    EPA Science Inventory

    A study has been undertaken to investigate the effect of blending PRB coal with an Eastern bituminous coal on the speciation of Hg across an SCR catalyst. In this project, a pilot-scale (1.2 MWt) coal combustor equipped with an SCR reactor for NOx control was used for evaluating ...

  17. Electrochemical, structural and surface characterization of nickel/zirconia solid oxide fuel cell anodes in coal gas containing antimony

    NASA Astrophysics Data System (ADS)

    Marina, Olga A.; Pederson, Larry R.; Coyle, Christopher A.; Thomsen, Edwin C.; Nachimuthu, Ponnusamy; Edwards, Danny J.

    The interactions of antimony with the nickel-zirconia anode in solid oxide fuel cells (SOFCs) have been investigated. Tests with both anode-supported and electrolyte-supported button cells were performed at 700 and 800 °C in synthetic coal gas containing 100 ppb to 9 ppm antimony. Minor performance loss was observed immediately after Sb introduction to coal gas resulting in ca. 5% power output drop. While no further degradation was observed during the following several hundred hours of testing, cells abruptly and irreversibly failed after 800-1600 h depending on Sb concentration and test temperature. Antimony was found to interact strongly with nickel resulting in extensive alteration phase formation, consistent with expectations based on thermodynamic properties. Nickel antimonide phases, NiSb and Ni 5Sb 2, were partially coalesced into large grains and eventually affected electronic percolation through the anode support. Initial degradation was attributed to diffusion of antimony to the active anode/electrolyte interface to form an adsorption layer, while the late stage degradation was due the Ni-Sb phase formation. Assuming an average Sb concentration in coal gas of 0.07 ppmv, a 500 μm thick Ni/zirconia anode-supported cell is not expected to fail within 7 years when operated at a power output of 0.5 W cm -2 and fuel utilization above 50%.

  18. XAFS SPECTROSCOPY ANALYSIS OF SELECTED HAP ELEMENTS IN FINE PM DERIVED FROM COAL COMBUSTION

    EPA Science Inventory

    X-ray absorption fine structure (XAFS) spectroscopy has been used to investigate the valence states and molecular structures of sulfur (S), chromium (Cr), arsenic (As), and zinc (Zn) in fine particulate matter (PM) separated from coal flyash produced in a realistic combustion sys...

  19. Application of selected chemical reactions to the organic chemistry of coal. [Ms thesis; 146 references

    SciTech Connect

    Metzler, R.M.

    1981-02-01

    This thesis involved 3 separate efforts. In the first trimethylsilyl ethers of a series model compounds were synthesized and their /sup 29/Si nmr spectra observed. This procedure was then used on the benzene soluble, pentane insoluble portion of Lovilia coal. The proton nmr showed approximately 30 percent of the protons present were silicon methyl protons, but the /sup 29/Si nmr showed no signal. This was not a completely surprisingly result. Coal is only about 10 percent oxygen by weight, and only about half of that is present as hydroxyl groups. Therefore, the silicon concentration in the coal will be low and /sup 29/Si makes up only 4.7 percent of the silicon atoms. It was then suggested and later proven that enhancement of the /sup 29/Si signal could be accomplished using cross-polarization between /sup 1/H and /sup 29/Si in silyl hydrides. A series of dimethylsilyl ethers were synthesized and their /sup 29/Si nmr observed using the technique of cross-polarization. These nmr were run in a 10 percent solution in benzene. These results show that the /sup 29/Si nmr signals of aromatic and aliphatic ethers are much closer together in the case of dimethylsilyl ethers than they were in the case of trimethylsilyl ethers. The second and third parts involve the reaction of Grignard reagent and trimethyliodosilane with organosulfur compounds chosen as structural models of coal. (LTN)

  20. Coal mine wastes. (Latest citations from the Selected Water Resources Abstracts database). Published Search

    SciTech Connect

    Not Available

    1993-07-01

    The bibliography contains citations concerning coal mining wastes, refuse dumps, and spoil. The disposal, environmental impact, waste treatment, utilization, and pollution control of these wastes are discussed. The revegetation of mined lands using waste water sludge is also considered. (Contains a minimum of 243 citations and includes a subject term index and title list.)

  1. Coal mine wastes. (Latest citations from the Selected Water Resources Abstracts database). Published Search

    SciTech Connect

    Not Available

    1994-05-01

    The bibliography contains citations concerning coal mining wastes, refuse dumps, and spoil. The disposal, environmental impact, waste treatment, utilization, and pollution control of these wastes are discussed. The revegetation of mined lands using waste water sludge is also considered. (Contains a minimum of 138 citations and includes a subject term index and title list.)

  2. Engineering Development of Advanced Physical Fine Coal Cleaning for Premium Fuel Applications: Task 9 - Selective agglomeration Module Testing and Evaluation.

    SciTech Connect

    Moro, N.` Jha, M.C.

    1997-09-29

    The primary goal of this project was the engineering development of two advanced physical fine coal cleaning processes, column flotation and selective agglomeration, for premium fuel applications. The project scope included laboratory research and bench-scale testing of both processes on six coals to optimize the processes, followed by the design, construction, and operation of a 2 t/hr process development unit (PDU). The project began in October, 1992, and is scheduled for completion by September 1997. This report summarizes the findings of all the selective agglomeration (SA) test work performed with emphasis on the results of the PDU SA Module testing. Two light hydrocarbons, heptane and pentane, were tested as agglomerants in the laboratory research program which investigated two reactor design concepts: a conventional two-stage agglomeration circuit and a unitized reactor that combined the high- and low-shear operations in one vessel. The results were used to design and build a 25 lb/hr bench-scale unit with two-stage agglomeration. The unit also included a steam stripping and condensation circuit for recovery and recycle of heptane. It was tested on six coals to determine the optimum grind and other process conditions that resulted in the recovery of about 99% of the energy while producing low ash (1-2 lb/MBtu) products. The fineness of the grind was the most important variable with the D80 (80% passing size) varying in the 12 to 68 micron range. All the clean coals could be formulated into coal-water-slurry-fuels with acceptable properties. The bench-scale results were used for the conceptual and detailed design of the PDU SA Module which was integrated with the existing grinding and dewatering circuits. The PDU was operated for about 9 months. During the first three months, the shakedown testing was performed to fine tune the operation and control of various equipment. This was followed by parametric testing, optimization/confirmatory testing, and finally a

  3. Extraction, separation, and analysis of high sulfur coal. Final report

    SciTech Connect

    Olesik, S.V.; Pekay, L.A.; Larkins, W. Jr.

    1992-05-31

    The work described in this report studies the removal of sulfur by oxidative interaction of various cupric salts with coal and also considers the possibility of removing organic sulfur by the selective interaction of supercritical ethanol with the organic coal matrix. Either one of these methods could potentially be used to pretreat coals before burning. The primary purpose of these studies is to ascertain the nature of the chemical reactions occurring, the chemical composition of the resultant products, and information on possible reaction mechanisms. This information should allow prediction of reasonable reaction conditions for the removal of organosulfur compound from coal.

  4. Extraction, separation, and analysis of high sulfur coal

    SciTech Connect

    Olesik, S.V.; Pekay, L.A.; Larkins, W. Jr.

    1992-05-31

    The work described in this report studies the removal of sulfur by oxidative interaction of various cupric salts with coal and also considers the possibility of removing organic sulfur by the selective interaction of supercritical ethanol with the organic coal matrix. Either one of these methods could potentially be used to pretreat coals before burning. The primary purpose of these studies is to ascertain the nature of the chemical reactions occurring, the chemical composition of the resultant products, and information on possible reaction mechanisms. This information should allow prediction of reasonable reaction conditions for the removal of organosulfur compound from coal.

  5. Novel microorganism for selective separation of coal from ash and pyrite; First quarterly technical progress report, September 1, 1993--November 30, 1993

    SciTech Connect

    Misra, M.; Smith, R.W.; Raichur, A.M.

    1993-12-31

    This report summarizes the progress made during the first quarter of the research project entitled ``A Novel Microorganism for Selective Separation of Coal from Ash and Pyrite,`` DOE Grant No. DE-FG22-93PC93215. The objective of this project is to study the effectiveness of a novel hydrophobic microorganism, Mycobacterium phlei (M. phlei), for the selective flocculation of coal from pyrite and ash-forming minerals. During the reporting period, three different coal samples: Illinois No. 6 coal, Kentucky No. 9 coal and Pittsburgh No. 8 coal, were collected to be used in the investigation. The microorganism, M. phlei, was obtained as freeze-dried cultures and the growth characteristics of the bacteria were studied. Scanning electron microphotographs revealed that M. phlei cells are coccal in shape and are approximately 1 {mu}m in diameter. Electrokinetic measurements showed that the Illinois No. 6 and Pittsburgh No. 8 coal samples had an isoelectric point (IEP) around pH 6 whereas M. phlei had an IEP around pH 1.5. Electrokinetic measurements of the ruptured microorganisms exhibited an increase in IEP. The increase in IEP of the ruputured cells was due to the release of fatty acids and polar groups from the cell membrane.

  6. EVALUATION AND MITIGATION OF VISIBLE ACIDIC AEROSOL PLUMES FROM COAL FIRED POWER BOILERS

    EPA Science Inventory

    The formation of sulfur trioxide during the combustion of coal can increase significantly following the installation and operation of selective catalytic reduction systems for reduction of nitrogen oxides. This can in turn lead to adverse environmental impacts, including visible...

  7. Nitrogen oxide removal processes for coal-fueled electric power generation

    SciTech Connect

    Van Nieuwenhuizen, Wm.

    1993-12-31

    There is a global trend requiring lower NO{sub x}, emissions from stationary combustion sources. When NO{sub x} is released into the atmosphere it contributes to photochemical smog and acid rain. Elevated ozone concentrations have been implicated in crop and forest damage, and adverse effects on human health. Several alternative technologies have been developed to reduce NO{sub x} emissions resulting from the combustion of coal. The alternatives, which range from combustion modifications, to addition of post-combustion systems, to use of alternate coal combustion technologies, provide different degrees of NO{sub x} reduction efficiency with different associated costs. Only by careful evaluation of site specific factors can the optimum technology for each application be chosen. This chapter will investigate the alternatives for NO{sub x} control for new, large utility steam generators using coal as a fuel.

  8. Surface intermediates in selective olefin oxidation and ammoxidation

    SciTech Connect

    Burrington, J.D.; Kartisek, C.T.; Grasselli, R.K.

    1983-02-01

    An investigation of the mechanism of the oxidation and ammoxidation of propylene was made. The products of the above reactions were acrylonitrile and acrolein for ammoxidation and oxidation, respectively. Also, the ammoxidation and oxidation of allyl alcohol, allyl amine, and their allylic deuterium substituted analogues was studied. It was concluded that oxidation and ammoxidation of propylene have the same rate determining step. Other conclusions about the reaction intermediates were also made.

  9. Nitric oxide selectively tunes inhibitory synapses to modulate vertebrate locomotion.

    PubMed

    McLean, David L; Sillar, Keith T

    2002-05-15

    We have explored the possible modulation by nitric oxide (NO) of inhibitory synaptic transmission mediated by either glycine or GABA during episodes of rhythmic fictive swimming in postembryonic Xenopus laevis tadpoles. Extracellular ventral-root recordings suggest a stage-dependent increase in the reliability and extent of the NO donor S-nitroso-n-acetylpenicillamine (SNAP; 0.1-1 mm) to inhibit swimming by reducing the frequency and shortening the duration of swim episodes. These effects of SNAP on the swimming rhythm at both developmental stages are corroborated by intracellular recordings from presumed motor neurons with sharp microelectrodes, which also suggest that NO inhibits swimming by facilitating both glycinergic and GABAergic inhibition. However, we found no evidence for NO modulation of the excitatory drive for swimming. In addition to presynaptic effects on inhibitory transmitter release, a pronounced postsynaptic membrane depolarization ( approximately 5-10 mV) and conductance decrease ( approximately 10-20%) are associated with bath application of SNAP. Hence, NO exerts inhibitory effects on swimming through multiple but selective actions on both the electrical properties of spinal neurons and on particular synaptic interconnections. The presynaptic and postsynaptic effects of NO act in concert to tune inhibitory synapses.

  10. Highly oxidized peroxisomes are selectively degraded via autophagy in Arabidopsis.

    PubMed

    Shibata, Michitaro; Oikawa, Kazusato; Yoshimoto, Kohki; Kondo, Maki; Mano, Shoji; Yamada, Kenji; Hayashi, Makoto; Sakamoto, Wataru; Ohsumi, Yoshinori; Nishimura, Mikio

    2013-12-01

    The positioning of peroxisomes in a cell is a regulated process that is closely associated with their functions. Using this feature of the peroxisomal positioning as a criterion, we identified three Arabidopsis thaliana mutants (peroxisome unusual positioning1 [peup1], peup2, and peup4) that contain aggregated peroxisomes. We found that the PEUP1, PEUP2, and PEUP4 were identical to Autophagy-related2 (ATG2), ATG18a, and ATG7, respectively, which are involved in the autophagic system. The number of peroxisomes was increased and the peroxisomal proteins were highly accumulated in the peup1 mutant, suggesting that peroxisome degradation by autophagy (pexophagy) is deficient in the peup1 mutant. These aggregated peroxisomes contained high levels of inactive catalase and were more oxidative than those of the wild type, indicating that peroxisome aggregates comprise damaged peroxisomes. In addition, peroxisome aggregation was induced in wild-type plants by exogenous application of hydrogen peroxide. The cat2 mutant also contained peroxisome aggregates. These findings demonstrate that hydrogen peroxide as a result of catalase inactivation is the inducer of peroxisome aggregation. Furthermore, an autophagosome marker, ATG8, frequently colocalized with peroxisome aggregates, indicating that peroxisomes damaged by hydrogen peroxide are selectively degraded by autophagy in the wild type. Our data provide evidence that autophagy is crucial for quality control mechanisms for peroxisomes in Arabidopsis.

  11. Selective laser sintering of MA956 oxide dispersion strengthened steel

    NASA Astrophysics Data System (ADS)

    Hunt, Ryan M.; Kramer, Kevin J.; El-Dasher, Bassem

    2015-09-01

    Oxide Dispersion Strengthened (ODS) steels' qualities of radiation damage resistance and high strength at high temperature make them promising nuclear structural materials. However, the dispersed yttria that gives ODS steel its beneficial qualities are generally compromised during joining processes, making fabrication difficult and expensive. The selective laser sintering process offers a potential path through this barrier by which net-shape parts can feasibly be built via additive manufacturing without fully melting the structure. Rastering a 400 W laser over a 110 μm MA956 ODS steel powder bed, we additively built parts with varying build conditions. Although density was achieved to within 97% of the wrought MA956, ultimate tensile strengths achieved only 65% of the wrought strength. Spectroscopy analysis points to the agglomeration of the yttria nano-particles as a possible explanation for the loss in strength. Further study might benefit from exploration of other parameters such as thinner powder build layers which would require less energy input to achieve sintering while minimizing time above the melting temperature.

  12. Characterization of selected Ohio coals to predict their conversion behavior relative to 104 North American Coals. [Factors correlating with liquefaction behavior

    SciTech Connect

    Whitacre, T. P.; Hunt, T. J.; Kneller, W. A.

    1982-02-01

    Twenty-six coal samples from Ohio were collected as washed and seam samples, and lithobodies within the seams. Characterization of these samples included determination of % maceral, % anti R/sub max/, LTA, chlorine content and proximate/ultimate and qualitative mineral analyses. These data were compared to data from a similar project by Yarzab, R.F., et al., 1980 completed at Pennsylvania State University using tetralin as the hydrogen donor solvent. The characteristics of these coals were correlated with liquefaction conversion and other data accrued on 104 North American coals by statistical analyses. Utilizing percent carbon, sulfur, volatile matter, reflectance, vitrinite and total reactive macerals, Q-mode cluster analysis demonstrated that Ohio coals are more similar to the coals of the Interior province than to those of the Appalachian province. Linear multiple regression analysis for the 104 North American coals provided a prediction equation for conversion (R = .96). The predicted conversion values for the samples range from 58.8 to 79.6%, with the Lower Kittanning (No. 5) and the Middle Kittanning (No. 6) coal seams showing the highest predicted percent conversion (respectively, 73.4 and 72.2%). The moderately low FSI values for the No. 5 and No. 6 coals (respectively, 2.5 and 3) and their moderately high alkaline earth content (respectively, 0.69 and 0.74%) suggest that these coals possess the best overall properties for conversion. Stepwise regression has indicated that the most important coal characteristics affecting conversion are, in decreasing order of importance: % volatile matter, % vitrinite and % total sulfur. Conversion processes can be expected to produce higher yields with Ohio coals due to the presence of such mineral catalysts as pyrite and kaolinite. It is believed that the presence of these disposable catalysts increases the marketability of Ohio coals.

  13. Novel microorganism for selective separation of coal from ash and pyrite. Seventh quarterly technical progress report, April 1, 1995--June 30, 1995

    SciTech Connect

    Misra, M.; Smith, R.W.; Raichur, A.M.

    1996-12-31

    The selective separation of pyrite and ash-forming minerals from coal can be accomplished by flotation, agglomeration and selective flocculation. The methods currently used for selective flocculation of coals include addition of natural or synthetic polymeric flocculants along with precise pH control. In some cases, these flocculants are nonselective or work imperfectly. It is known that many highly charged planktonic algae and bacteria will adhere to certain solid surfaces if the charge or hydrophobic interaction between the organism and the solids are favorable for adhesion. The resultant microorganism-mineral entities, if formed, can flocculate and can be separated. In addition, many living organisms produce extracellular biopolymers that can also cause flocculation. The microorganism, M. phlei, has the properties of being both highly charged and highly hydrophobic. The aim of the present investigation is to study the effectiveness of M. phlei and biopolymers derived from the organism for selective flocculation and separation of fine coal from pyrite and ash.

  14. Novel microorganism for selective separation of coal from ash and pyrite. Third quarterly technical progress report, March 1, 1994--May 31, 1994

    SciTech Connect

    Misra, M.; Smith, R.W.; Raichur, A.M.

    1994-11-01

    The selective separation of pyrite and ash-forming minerals from coal can be accomplished by flotation, agglomeration and selective flocculation. The methods currently used for selective flocculation of coals include addition of natural or synthetic polymeric flocculants along with precise pH control. In some cases, these flocculants are nonselective or work imperfectly. It is known that many highly charged planktonic algae and bacteria will adhere to certain solid surface if the charge or hydrophobic interaction between the organism and the solids are favorable for adhesion. The resultant microorganism-mineral entities if formed can flocculate and can be separated. In addition, many living organism produce extracellular biopolymers that can also cause flocculation. The microorganism, M. phlei, has the properties of being both highly charged and highly hydrophobic. The aim of the present investigation is to study the effectiveness of M. phlei and biopolymers derived from the organism for selective flocculation of fine coal from ash and pyrite.

  15. Reactivity to oxidation of the active centers formed in the thermal degradation of the brown coal of the Irsha-Borodino deposit

    SciTech Connect

    Sukhov, V.A.; Davydova, Zh.A.; Lukovnikov, A.F.; Nedoshivin, Yu.A.; Neshin, Yu.I.

    1983-01-01

    In the thermal degradation of a brown coal at 400/sup 0/C in vacuum, the formation of PMCs takes place as the result of the thermal decomposition of free acid groups, mainly carboxylic, and of the organomineral compounds. The PMCs formed differ in reactivity. Simultaneously with the formation of PMCs in the thermal degradation of a coal there is probably a simulataneous formation of structural groupings of the ketene type actively interacting with oxygen by a radical mechanism, which leads to an accumulation of a considerable amount of new PMCs in the coal. The overall tendency of the heat-treated coals to undergo oxidation depends on the qualitative and quantitative ratio of all the radicals and structures formed in the thermal degradation of the coal. The more completely the thermal degradation of the organomineral compounds present in brown coals take place, the larger is the amount of structural groupings actively interacting with oxygen to form PMCs that is produced and the greater is the heat effect of the oxidation of the HTCs.

  16. Effects of Mikania glomerata Spreng. and Mikania laevigata Schultz Bip. ex Baker (Asteraceae) extracts on pulmonary inflammation and oxidative stress caused by acute coal dust exposure

    SciTech Connect

    Freitas, T.P.; Silveira, P.C.; Rocha, L.G.; Rezin, G.T.; Rocha, J.; Citadini-Zanette, V.; Romao, P.T.; Dal-Pizzol, F.; Pinho, R.A.; Andrade, V.M.; Streck, E.L.

    2008-12-15

    Several studies have reported biological effects of Mikania glomerata and Mikania laevigata, used in Brazilian folk medicine for respiratory diseases. Pneumoconiosis is characterized by pulmonary inflammation caused by coal dust exposure. In this work, we evaluated the effect of pretreatment with M. glomerata and M. laevigata extracts (MGE and MLE, respectively) (100 mg/kg, s.c.) on inflammatory and oxidative stress parameters in lung of rats subjected to a single coal dust intratracheal instillation. Rats were pretreated for 2 weeks with saline solution, MGE, or MLE. On day 15, the animals were anesthetized, and gross mineral coal dust or saline solutions were administered directly in the lung by intratracheal instillation. Fifteen days after coal dust instillation, the animals were killed. Bronchoalveolar lavage (BAL) was obtained; total cell count and lactate dehydrogenase (LDH) activity were determined. In the lung, myeloperoxidase activity, thiobarbituric acid-reactive substances (TBARS) level, and protein carbonyl and sulfhydryl contents were evaluated. In BAL of treated animals, we verified an increased total cell count and LDH activity. MGE and MLE prevented the increase in cell count, but only MLE prevented the increase in LDH. Myeloperoxidase and TBARS levels were not affected, protein carbonylation was increased, and the protein thiol levels were decreased by acute coal dust intratracheal administration. The findings also suggest that both extracts present an important protective effect on the oxidation of thiol groups. Moreover, pretreatment with MGE and MLE also diminished lung inflammatory infiltration induced by coal dust, as assessed by histopathologic analyses.

  17. CeO2-TiO2 catalysts for catalytic oxidation of elemental mercury in low-rank coal combustion flue gas.

    PubMed

    Li, Hailong; Wu, Chang-Yu; Li, Ying; Zhang, Junying

    2011-09-01

    CeO(2)-TiO(2) (CeTi) catalysts synthesized by an ultrasound-assisted impregnation method were employed to oxidize elemental mercury (Hg(0)) in simulated low-rank (sub-bituminous and lignite) coal combustion flue gas. The CeTi catalysts with a CeO(2)/TiO(2) weight ratio of 1-2 exhibited high Hg(0) oxidation activity from 150 to 250 °C. The high concentrations of surface cerium and oxygen were responsible for their superior performance. Hg(0) oxidation over CeTi catalysts was proposed to follow the Langmuir-Hinshelwood mechanism whereby reactive species from adsorbed flue gas components react with adjacently adsorbed Hg(0). In the presence of O(2), a promotional effect of HCl, NO, and SO(2) on Hg(0) oxidation was observed. Without O(2), HCl and NO still promoted Hg(0) oxidation due to the surface oxygen, while SO(2) inhibited Hg(0) adsorption and subsequent oxidation. Water vapor also inhibited Hg(0) oxidation. HCl was the most effective flue gas component responsible for Hg(0) oxidation. However, the combination of SO(2) and NO without HCl also resulted in high Hg(0) oxidation efficiency. This superior oxidation capability is advantageous to Hg(0) oxidation in low-rank coal combustion flue gas with low HCl concentration.

  18. CeO2-TiO2 catalysts for catalytic oxidation of elemental mercury in low-rank coal combustion flue gas.

    PubMed

    Li, Hailong; Wu, Chang-Yu; Li, Ying; Zhang, Junying

    2011-09-01

    CeO(2)-TiO(2) (CeTi) catalysts synthesized by an ultrasound-assisted impregnation method were employed to oxidize elemental mercury (Hg(0)) in simulated low-rank (sub-bituminous and lignite) coal combustion flue gas. The CeTi catalysts with a CeO(2)/TiO(2) weight ratio of 1-2 exhibited high Hg(0) oxidation activity from 150 to 250 °C. The high concentrations of surface cerium and oxygen were responsible for their superior performance. Hg(0) oxidation over CeTi catalysts was proposed to follow the Langmuir-Hinshelwood mechanism whereby reactive species from adsorbed flue gas components react with adjacently adsorbed Hg(0). In the presence of O(2), a promotional effect of HCl, NO, and SO(2) on Hg(0) oxidation was observed. Without O(2), HCl and NO still promoted Hg(0) oxidation due to the surface oxygen, while SO(2) inhibited Hg(0) adsorption and subsequent oxidation. Water vapor also inhibited Hg(0) oxidation. HCl was the most effective flue gas component responsible for Hg(0) oxidation. However, the combination of SO(2) and NO without HCl also resulted in high Hg(0) oxidation efficiency. This superior oxidation capability is advantageous to Hg(0) oxidation in low-rank coal combustion flue gas with low HCl concentration. PMID:21770402

  19. Quantitating the efficiency of the coal mine personal respirable dust sampler for sampling oxide fumes.

    PubMed

    Tomb, T F; Beckert, A J; Treaftis, H N

    1976-08-01

    Coal mine environments containing fume contaminants are assessed using the standard personal respirable dust sampler. The effect of the first-stage collector and filter on the total concentration measured was evaluated. The results showed that the personal respirable dust sampler could be used to sample fumes with TLV's greater than 1.0 mg/m3.

  20. Effects of Ceric Oxide Coatings on Materials Performance of 430 Steel in Coal Synthetc Gas

    SciTech Connect

    Ziomek-Moroz, M. Jablonski, P

    2011-12-21

    The surfaces of low silicon and aluminum 430 stainless steel (UNS 43000) coupons with and without ceria (CeO2) surface treatment were investigated after exposure to simulated coal syngas based fuel at 800 C. The results indicate a different mechanism of carburization for the ceria treated steel than that for the untreated steel.

  1. Carbon monoxide detection of chemisorbed oxygen in coal and other carbonaceous materials

    USGS Publications Warehouse

    Hinckley, C.C.; Wiltowski, T.; Wiltowska, T.; Ellison, D.W.; Shiley, R.H.; Wu, L.

    1990-01-01

    The oxidation of carbon monoxide by mildly oxidized and devolatilized coal samples was studied thermogravimetrically. The oxidation was attributed to oxygen chemisorbed on inorganic components of the coals. The reaction of CO with pyrite producing carbonyl sulphide, OCS, accompanied the oxidation. A mechanism for CO oxidation is proposed in which active oxygen chemisorbed on the inorganic components of the coal directly oxidized CO to CO2, and facilitates the chemisorption of CO on the coal as carbonate. A factor, ?? = ( 11 14) [1 - ( Wn Wc)], was derived where Wn is the sample weight loss not attributed to OCS formation, and Wc is the estimated weight of evolved CO2. This quantity is proportional to the fraction of CO2 produced by the direct oxidation of CO, and was used to compare the coal samples studied. Samples of an Illinois No. 5 coal yielded average ?? values of 0.7 and those of an Illinois No. 6 coal yielded values of 0.6, indicating that in these cases, the majority of CO2 produced came from the direct oxidation of CO. The results obtained for the coal samples are compared with a selection of carbonaceous samples for which the proposed mechanism does not apply. ?? 1990.

  2. Selective Growth of Noble Gases at Metal/Oxide Interface.

    PubMed

    Takahashi, Keisuke; Oka, Hiroshi; Ohnuki, Somei

    2016-02-17

    The locations and roles of noble gases at an oxide/metal interface in oxide dispersed metal are theoretically and experimentally investigated. Oxide dispersed metal consisting of FCC Fe and Y2Hf2O7 (Y2Ti2O7) is synthesized by mechanical alloying under a saturated Ar gas environment. Transmission electron microscopy and density functional theory observes the strain field at the interface of FCC Fe {111} and Y2Hf2O7 {111} whose physical origin emerges from surface reconstruction due to charge transfer. Noble gases are experimentally observed at the oxide (Y2Ti2O7) site and calculations reveal that the noble gases segregate the interface and grow toward the oxide site. In general, the interface is defined as the trapping site for noble gases; however, transmission electron microscopy and density functional theory found evidence which shows that noble gases grow toward the oxide, contrary to the generally held idea that the interface is the final trapping site for noble gases. Furthermore, calculations show that the inclusion of He/Ar hardens the oxide, suggesting that material fractures could begin from the noble gas bubble within the oxides. Thus, experimental and theoretical results demonstrate that noble gases grow from the interface toward the oxide and that oxides behave as a trapping site for noble gases. PMID:26840881

  3. Surface properties of photo-oxidized bituminous coals. Quarterly technical report, October 1, 1996--December 31, 1996

    SciTech Connect

    Mitchell, G.; Davis, A.

    1997-02-01

    During this reporting period, three vitrain concentrate samples crushed to -200 mesh were irradiated (photo-oxidized) for different time periods (0, 10, 50 and 100 min) using the BLAK-RAY ultraviolet lamp to obtain samples suitable for pyrolysis GC/MS. These samples will be used to investigate whether the levels of photo-oxidation induced with increasing UV irradiation can be detected and measured in bulk vitrains using the technique. The analyses have not been fully completed. Further, additional analysis of reflectance-mode FTIR results obtained from polished blocks of vitrain is currently under way. This evaluation involves calculating the second derivative of the spectra in an attempt to better identify the spectral regions of most significant change resulting from photo-oxidation. These analyses, along with final analytical tests that will destroy the irradiated surfaces, including electron microprobe analysis for near- surface oxygen concentration and x-ray mapping, and measurement of reflectance in oil immersion, are under way and will be completed by the end of February, 1997. During this report period we have begun the preparation of a manuscript tentatively entitled, ``Time Resolved C-NEXAFS Analysis of the Chemistry of Photochemical Alteration of Vitrinite. This publication will discuss our efforts in utilizing Scanning Transmission X-ray Microscopy as a tool to better define the kinetics of photo-oxidation or vitrinite from coals of three different ranks by measuring changes in regions near the carbon-edge absorption.

  4. Occurrence of microbial acetate-oxidation in ~2 km-deep coal-bearing sediments off the Shimokita Peninsula, Japan (IODP Expedition 337)

    NASA Astrophysics Data System (ADS)

    Ijiri, A.; Inagaki, F.

    2015-12-01

    During the Integrated Ocean Drilling Program (IODP) Expedition 337 in 2012, the riser-drilling vessel Chikyu extended the previous world depth record of scientific ocean drilling and made one of the deepest scientific borehole down to 2466 m below the seafloor (mbsf) at Site C0020 Hole A off the Shimokita Peninsula, Japan. The sedimentary sequence consists of 17 lignite layers below 1.5 km bellow the seafloor. Microbiological and geochemical data consistently showed evidence for the existence of microbial communities associated with lignite coal beds in the coal-bearing sediments (Inagaki and Hinrichs et al., Science, 2015). Since lignite coals produce substantial dissolved organic compounds during the burial alternation process, volatile fatty acids may play important roles for microbial life and its activity in the deep sedimentary environment. To address this hypothesis, we measured methanogenic and acetate-oxidation activities by radiotracer incubation experiments using 14C-labelled substrate ([2-14C]-acetate) immediately after core recovery. Activity of aceticlastic methanogenesis was observed in the sediment above the coal-baring layers (>1990 mbsf), ranging from 0.2 to 1.2 pmol cm-3 d-1. The highest activity was observed in a coal-bed horizon at 1990 mbsf. However, aceticlastic methanogenesis was below the detection limit in sediment samples below the 2 km-coal layers. Activity of acetate oxidation to CO2 was measured by 14CO2 production rate from [2-14C]-acetate. Interestingly, the acetate-oxidation activity was observed in sediments above the coal beds, which values were generally higher than those of methanogenesis with the maximum value of 33 pmol cm-3 d-1 at 1800 mbsf. The rates gradually decreased with increasing depth from 1800 mbsf and reached below the detection limit (i.e., 0.05 pmol cm-3 d-1) in 2 km-deep coal-bed samples. The occurrence of relatively high acetate oxidation at ~1800 mbsf above the coal formation suggests that microbes respire

  5. Selective catalytic reduction of nitric oxide with ammonia over silica-supported vanadium oxide catalyst

    SciTech Connect

    Qajar, J.; Mowla, D.

    2009-07-01

    The selective catalytic reduction (SCR) of nitric oxide with excess ammonia in the presence of oxygen on silica-supported vanadium oxide catalyst was studied in a packed-bed reactor, and a mathematical model was proposed for the processes occurring in the reactor. Experimental data were presented for evaluation of the accuracy of the proposed model. Good agreement was observed between the measured and calculated values of the conversion in the outlet of the reactor. Once the validity of the proposed model was verified, it was used to examine the effects of different parameters such as feed temperature, inlet feed composition, and gas hourly space velocity (GHSV) on the conversion of NO over V{sub 2}O{sub 5}/SiO{sub 2} catalyst for practical application. The results for the employed catalyst showed that high NO conversion occurred at temperatures of 280-300C, GHSV less than 2000h{sup -1} (STP), and O{sub 2} concentration greater than 10% v/v. These results clearly demonstrate the high potential for this catalyst to be applied commercially for the control of NOx emissions from flue gases of different sources.

  6. Selective reduction of nitric oxides with ammonia using a cellular block catalyst

    SciTech Connect

    M.V. D'yakov; A.I. Kozlov; E.S. Lukin

    2004-03-15

    An aluminum-vanadium cellular block catalyst for selective reduction of nitric oxides with ammonia has been developed. With an average degree of conversion of oxides over 90%, the efficiency of the proposed catalyst is significantly higher than that of industrial catalysts currently used. Such catalyst can be recommended for use in selective plants for purification of waste gases from nitric oxides, which makes it possible to significantly decrease the cost of making a catalyst block.

  7. Selective Removal of Technetium from Water Using Graphene Oxide Membranes.

    PubMed

    Williams, Christopher D; Carbone, Paola

    2016-04-01

    The effective removal of radioactive technetium ((99)Tc) from contaminated water is of enormous importance from an environmental and public health perspective, yet many current methodologies are highly ineffective. In this work, however, we demonstrate that graphene oxide membranes may remove (99)Tc, present in the form of pertechnetate (TcO4(-)), from water with a high degree of selectivity, suggesting they provide a cost-effective and efficient means of achieving (99)Tc decontamination. The results were obtained by quantifying and comparing the free energy changes associated with the entry of the ions into the membrane capillaries (ΔFperm), using molecular dynamics simulations. Initially, three capillary widths were investigated (0.35, 0.68, and 1.02 nm). In each case, the entry of TcO4(-) from aqueous solution into the capillary is associated with a decrease in free energy, unlike the other anions (SO4(2-), I(-), and Cl(-)) investigated. For example, in the model with a capillary width of 0.68 nm, ΔFperm(TcO4(-)) = -6.3 kJ mol(-1), compared to ΔFperm(SO4(2-)) = +22.4 kJ mol(-1). We suggest an optimum capillary width (0.48 nm) and show that a capillary with this width results in a difference between ΔFperm(TcO4(-)) and ΔFperm(SO4(2-)) of 89 kJ mol(-1). The observed preference for TcO4(-) is due to its weakly hydrating nature, reflected in its low experimental hydration free energy.

  8. A convenient and selective palladium-catalyzed aerobic oxidation of alcohols.

    PubMed

    Gowrisankar, Saravanan; Neumann, Helfried; Gördes, Dirk; Thurow, Kerstin; Jiao, Haijun; Beller, Matthias

    2013-11-18

    An efficient procedure for the oxidation of primary and secondary alcohols to aldehydes and ketones, respectively, with molecular oxygen under ambient conditions has been achieved. By applying catalytic amounts of Pd(OAc)2 in the presence of tertiary phosphine oxides (O=PR3) as ligands, a variety of substrates are selectively oxidized without formation of ester byproducts. Spectroscopic investigations and DFT calculations suggest stabilization of the active palladium(II) catalyst by phosphine oxide ligands.

  9. Selective uptake of pyrrolizidine N-oxides by cell suspension cultures from pyrrolizidine alkaloid producing plants.

    PubMed

    von Borstel, K; Hartmann, T

    1986-02-01

    The N-oxides of pyrrolizidine alkaloids such as senecionine or monocrotaline are rapidly taken up and accumulated by cell suspension cultures obtained from plants known to produce pyrrolizidines, i.e. Senecio vernalis, vulgaris, viscosus (Asteraceae) and Symphytum officinale (Boraginaceae). The transport of the N-oxides into the cells is a specific and selective process. Other alkaloid N-oxides such as sparteine N-oxide are not taken up. Cell cultures from plant species which do not synthesize pyrrolizidine alkaloids are unable to accumulate pyrrolizidine N-oxides. The suitability of the pyrrolizidine N-oxides in alkaloid storage and accumulation is emphasized. PMID:24247963

  10. Novel microorganism for selective separation of coal from ash and pyrite. Sixth quarterly technical progress report, January 1, 1995--March 31, 1995

    SciTech Connect

    Misra, M.; Smith, R.W.; Raichur, A.M.

    1995-08-01

    The objective of this research project is to study the effectiveness of a novel hydrophobic microorganism, Mycobacterium phlei (M. phlei), for the selective flocculation of coal from pyrite and ash forming minerals. During the reporting period, the flocculation efficiencies of Illinois No. 6 and KY No. 9 coal in the presence of whole and ruptured cells of M. phlei were studied. The effect of synthetic flocculants were also studied for comparison at selected pH values. Results showed that the whole cells of M. phlei can flocculate coal very effectively and rapidly for both the coal samples. However, with ruptured cells of M. phlei the flocculation efficiency is significantly less which can be attributed to the loss of extracellular surfactants during rupturing. Separation of flocs using column flotation was studied for both the coal samples in the acidic pH range. Results indicated that excellent rejection of pyritic sulfur and ash could be obtained with a high combustible recovery. DLVO calculations were performed for all the minerals used in this study to calculate the interaction energies in the presence of whole cells and ruptured cells of M. phlei. A minimum in interaction energy is observed between coal and whole cells of M. phlei at pH 4 which is probably responsible for the higher adhesion and flocculation efficiencies at the pH. However, with ruptured cells the interaction energy increases thus decreasing the amount of M. phlei cells adhering to the surface.

  11. OXIDATIVE DAMAGE-RELATED GENES AKR1C3 AND OGG1 MODULATE RISKS FOR LUNG CANCER DUE TO EXPOSURE TO PAH-RICH COAL COMBUSTION EMISSIONS

    EPA Science Inventory

    We studied polymorphisms in genes that generate, prevent, or repair oxidative damage and lung cancer risk among 118 cases and 113 controls in Xuan Wei China, where extremely high lung cancer rates are caused by indoor exposure to smoky coal. SOD2-Vak16Ala and NQO1-Pro 187Ser were...

  12. Practical nitric oxide measurement employing a nitric oxide-selective electrode

    NASA Astrophysics Data System (ADS)

    Ichimori, K.; Ishida, H.; Fukahori, M.; Nakazawa, H.; Murakami, E.

    1994-08-01

    An NO-selective electrode was developed as an easily applicable tool for a real-time nitric oxide (NO) measurement. The working electrode (0.2 mm diam) was made from Pt/Ir alloy coated with a three-layered membrane. The counterelectrode was made from a carbon fiber. When a stable NO donor, S-nitroso-N-acetyl-dl-penicillamine, was applied, the electrode current increased in a dose-dependent fashion. The current and calculated NO concentration showed a linear relationship in the range from 0.2 nM (S/N=1) to 1 μM of NO. The response of the electrode was 1.14±0.09 s. The effects of temperature, pH, and chemicals other than NO on the electrode current were also evaluated. Electrodes which were placed in the luminal side of rat aortic rings exhibited 30 pA of current due to NO generation induced by the addition of 10-6 M of acetylcholine. The current was eliminated in the presence of 50 μM NG-monomethyl-L-arginine, an inhibitor of NO synthase. Thus, this NO-selective electrode is applicable to real-time NO assay in biological systems.

  13. Pathways for conversion of char nitrogen to nitric oxide during pulverized coal combustion

    SciTech Connect

    Molina, A.; Murphy, J.J.; Blevins, L.G.; Shaddix, C.R.; Winter, F.; Haynes, B.S.

    2009-03-15

    The conversion of nitrogen in char (char-N) to NO was studied both experimentally and computationally. In the experiments, pulverized coal char was produced from a U.S. high-volatile bituminous coal and burned in a dilute suspension at 1170 K, 1370 K and 1570 K, at an excess oxygen concentration of 8% (dry), with different levels of background NO. In some experiments, hydrogen bromide (HBr) was added to the vitiated air as a tool to alter the concentration of gas-phase radicals. During char combustion, low NO concentration and high temperature promoted the conversion of char-N to NO. HBr addition altered NO production in a way that depended on temperature. At 1170 K the presence of HBr increased NO production by 80%, whereas the addition of HBr decreased NO production at higher temperatures by 20%. To explain these results, three mechanistic descriptions of char-N evolution during combustion were evaluated with computational models that simulated (a) homogeneous chemistry in a plug-flow reactor with entrained particle combustion, and (b) homogeneous chemistry in the boundary layer surrounding a reacting particle. The observed effect of HBr on NO production could only be captured by a chemical mechanism that considered significant release of HCN from the char particle. Release of HCN also explained changes in NO production with temperature and NO concentration. Thus, the combination of experiments and simulations suggests that HCN evolution from the char during pulverized coal combustion plays an essential role in net NO production. (author)

  14. Electrochemical, Structural and Surface Characterization of Nickel/Zirconia Solid Oxide Fuel Cell Anodes in Coal Gas Containing Antimony

    SciTech Connect

    Marina, Olga A.; Pederson, Larry R.; Coyle, Christopher A.; Thomsen, Edwin C.; Nachimuthu, Ponnusamy; Edwards, Danny J.

    2011-02-27

    The interaction of antimony with the nickel-zirconia solid oxide fuel cell (SOFC) anode has been investigated. Tests with both anode-supported and electrolyte-supported button cells were performed at 700 and 800oC in synthetic coal gas containing 10 ppb to 9 ppm antimony. Minor performance loss was observed immediately after Sb introduction to coal gas resulting in ca. 5 % power output drop. While no further degradation was observed during the following several hundred hours of testing, cells abruptly and irreversibly failed after 800-1500 hours depending on Sb concentration and test temperature. Antimony was found to interact strongly with nickel and result in extensive alteration phase formation, consistent with expectations based on thermodynamic properties. Nickel antimonide phases, NiSb and Ni5Sb2, were partially coalesced into large grains and eventually affected electronic percolation through the anode support. Initial degradation was attributed to diffusion of antimony to the active anode/electrolyte interface to form an adsorption layer.

  15. Enzymatic coal desulfurization

    SciTech Connect

    Kern, E.E.; Menger, W.M.; Odelson, D.A.; Sinskey, A.S.; Wise, D.L.; Trantolo, D.J.

    1992-03-10

    This patent describes a method for reducing the total sulfur content of a fossil fuel containing organic sulfur. It comprises contacting the fossil fuel with a solution containing sulfatase to release organic sulfur as water-soluble free sulfate; recovering from the solution a fossil fuel having a reduced sulfur content. Wherein the fossil fuel is coal, petroleum, or a process-derived product thereof. It further comprises the step of: contacting the fossil fuel with an oxidizing agent. Wherein the sulfatase is selected from the group consisting of Aerobacter species sulfatase, limpet sulfatase, abalone entrail sulfatase, and Helix species sulfatase.

  16. Surface properties of photo-oxidized bituminous coals. Technical progress report for the period July--September 1996

    SciTech Connect

    Mitchell, G.; Werner, D.; Davis, A.; Chander, S.

    1996-11-01

    During this report period, irradiation (photo-oxidation) of all six vitrain concentrates for three different time periods (10, 50 and 100 min) using the BLAK-RAY ultraviolet lamp was completed along with film flotation and surface luminescence measurements for each condition. Flotation results from photo-oxidized powdered vitrains appear to be contrary to earlier results obtained from contact angle measurements on polished surfaces. Some of the more strongly photo-oxidized powders, particularly for hvAb and mvb coals, exhibit greater hydrophobicity. The changes in hydrophobicity as well as a measured decrease in surface luminescence with increasing irradiation time, clearly shows that UV irradiation has had an influence on surface properties. There is some possibility that increasing exposure to the UV source may cause mobilization of aliphatic compounds (oils) from the fresh fracture surfaces of vitrain. These compounds, once exuded onto the surface could act like a natural flotation collector that would both increase particle hydrophobicity and may obscure the surface from further oxidation. Because most aliphatic compounds do not luminesce, their presence on the surface would reduce measured luminescence. A second possible explanation is that the types of oxygen functional groups which form during UV irradiation may inhibit or promote hydrophobicity depending upon their concentration. In an attempt to resolve these issues several analytical tests will be undertaken. Pyrolysis GC/MS will be used to investigate whether photo-oxidation of bulk vitrains was sufficiently severe with increasing UV irradiation. Reflectance-mode FTIR will be used to measure changes in surface chemistry for some of the irradiated powdered vitrains.

  17. Bioaugmentation of biological contact oxidation reactor (BCOR) with phenol-degrading bacteria for coal gasification wastewater (CGW) treatment.

    PubMed

    Fang, Fang; Han, Hongjun; Zhao, Qian; Xu, Chunyan; Zhang, Linghan

    2013-12-01

    This study was conducted to evaluate the performance of the biological contact oxidation reactor (BCOR) treating coal gasification wastewater (CGW) after augmented with phenol degrading bacteria (PDB). The PDB were isolated with phenol, 4-methyl phenol, 3,5-dimethyl phenol and resorcinol as carbon resources. Much of the refractory phenolic compounds were converted into easily-biodegradable compounds in spite of low TOC removal. The bioaugmentation with PDB significantly enhanced the removal of COD, total phenols (TP) and NH3-N, with efficiencies from 58% to 78%, 66% to 80%, and 5% to 25%, respectively. In addition, the augmented BCOR exhibited strong recovery capability in TP and COD removal while recovery of NH3-N removal needed longer time. Microbial community analysis revealed that the PDB presented as dominant populations in the bacteria consortia, which in turn determined the overall performance of the system.

  18. Desulfurization and de-ashing of a mixture of subbituminous coal and gangue minerals by selective oil agglomeration

    SciTech Connect

    Ayhan, F.D.

    2009-11-15

    The aim of this study was to investigate desulfurization and de-ashing of a mixture of subbituminous coal and gangue minerals by the agglomeration method. For this purpose, experimental studies were conducted on a mixture containing subbituminous coal, pyrite, quartz and calcite. The effects of some parameters that markedly influence the effectiveness of selective oil agglomeration, such as solid concentration, pH, bridging liquid type and concentration, and depressant type and amount, were investigated. Agglomeration results showed that the usage of various depressants (Na{sub 2}SiO{sub 3}, FeCl3, corn starch, wheat starch) in the agglomeration medium has a positive effect on the reduction of ash and total sulfur content of agglomerates. It was found that an agglomerate product containing 3.03% total sulfur and 25.01% ash with a total sulfur reduction of 56.71% was obtained from a feed that contained 7% total sulfur and 43.58% ash when FeCl{sub 3} was used in the agglomeration medium.

  19. Effects of coal mining on the water quality and sedimentation of Lake Tuscaloosa and selected tributaries, North River basin, Alabama

    USGS Publications Warehouse

    Cole, E.F.

    1985-01-01

    Lake Tuscaloosa, a reservoir on North River, is the primary source of water supply for the city of Tuscaloosa, Alabama, and surrounding areas. Between October 1982 and September 1983, 14 sites in the North River basin were sampled to determine if surface coal mining has impacted the quality of water in the lake and selected tributaries. Water draining mined basins showed increases in specific conductance, sulfate concentrations , and dissolved and total recoverable iron and manganese concentrations after mining started in 1975. Although water in the reservoir has become more mineralized with only an estimated 5 percent of the basin mined, total dissolved solids concentrations are still very low, ranging from 28 to 35 milligrams per liter at the dam. The quality of water at most sites was, except for pH, iron, and manganese, within secondary drinking water standards. The pH of water from streams draining either mined or unmined basins was generally less than 6.5. Sedimentation has occurred at most measured lake cross sections since impoundment. However, natural factors such as steep overland and channel slopes, may cause more sedimentation in the lake from unmined basins than from coal mining in a different basin. (USGS)

  20. Novel microorganism for selective separation of coal from ash and pyrite. Fourth quarterly technical progress report, July 1, 1994--September 30, 1994

    SciTech Connect

    Misra, M.; Smith, R.W.

    1995-12-31

    This report summarizes the progress made during the fourth quarter of the research 9 project entitled {open_quotes}A Novel Microorganism for Selective Separation of Coal from Ash and Pyrite{close_quotes}. The objective of this project is to study the effectiveness of a novel hydrophobic microorganism, Mycobacterium phlei (M. phlei), for the selective flocculation of coal from pyrite and ash forming minerals. During the reporting period, the adhesion of M phlei on the surface of quartz was investigated as a function of pH and conditioning time. Results showed that the little adhesion of M phlei onto quartz occurred. The amount of M phlei adsorbed onto the surface of quartz was less compared to coal. These results suggest that it would be possible to flocculate coal selectively from ash forming minerals. Flocculation tests conducted with Illinois No. 6 coal showed that rapid flocculation takes place in the pH range of 3-4. Flocculation efficiency is highly dependent upon the M. phlei concentration.

  1. SELECTIVE OXIDATION OF ALCOHOLS - COMPARING DIFFERENT CATALYTIC PROCESSES

    EPA Science Inventory

    Oxidation of alcohols to aldehydes, ketones or carboxylic acids is one of the most desirable chemical transformations in organic synthesis as these products are important precursors and intermediates for many drugs, vitamins and fragrances. Numerous methods are available for alc...

  2. Water quality of selected streams in the coal area of southeastern Montana

    USGS Publications Warehouse

    Knapton, J.R.; McKinley, P.W.

    1977-01-01

    This report summarizes and evaluates water-quality data collected at 35 stream sites the the coal region of southeastern Montana. Sarpy Creek, Armells Creek, and Rosebud Creek sometimes have dissolved-solids concentrations that cause water to be marginal for agricultural purposes. At times of rainfall and snowmelt, the runoff water mixes with the base-flow component to improve the overall quality. Water in the Tongue River generally showed a downstream degradation in which some changes were related to lithology of the aquifers contributing water to streamflow. Water from Pumpkin Creek and Mizpah Creek is used mostly for cattle watering. To some extent water is used for irrigation although the salinity hazard was often high. The chemical quality of the Powder River changed little during flow downstream. High sediment loads of the river acted as transporting agents for many of the plant nutrients and trace-element constituents. (Woodard-USGS)

  3. Diesel-exhaust/coal-dust exposure study: characterization of selected vapor-phase organic emissions

    SciTech Connect

    Lunsford, R.A.; Okenfuss, J.R.; Shulman, S.A.

    1984-02-28

    In efforts to characterize the atmospheres present in animal exposure chambers, samples of the air were taken during coal dust and diesel exhaust inhalation studies. No detectable quantities of phenol, cresol, and the xylenols were found in the exposure chambers. Formaldehyde and acetaldehyde were present at slightly under 40 parts per billion (ppb) concentration levels. Other aldehydes present in the chambers were at much lower concentrations, about 6ppb. Formaldehyde was the only aldehyde consistently present in the nondiesel chambers, at 7ppb. It is suggested that the water scrubber on the diesel engine used in the study might have moderated the concentrations of water-soluble pollutants, such as aldehydes and phenols. A combination of analytical results suggests that formaldehyde, acetaldehyde, and acrolein were the major aldehydes present in the diesel exhaust, each at levels less than 100ppb.

  4. [Application of selected microorganisms for organic sulfur removal from coal]. Quarterly progress report, March 15, 1990--June 15, 1990

    SciTech Connect

    Elmore, B.B.

    1990-06-20

    Research continues on methods for desulfurization of coal using microorganisms. Topics reported on this term include: coal procurement and preparation, microbial removal of pyrite and sulfate, analytical procedures for characterization of total organic sulfur, organic sulfur removal, microbial activity on model coal organosulfur compounds, screening/detection assays, and monitoring of desulfurization activity. (VC)

  5. [Application of selected microorganisms for organic sulfur removal from coal]. Quarterly progress report, December 15, 1989--March 15, 1990

    SciTech Connect

    Not Available

    1990-03-20

    Research continues on methods to desulfurize coal using microorganisms. Topics reported on this term include: coal procurement and preparation, microbial pyrite and sulfate removal, analytical procedures for characterization of total organic sulfur, microbial activity on model coal organosulfur compounds, screening assays, and plasmid mediation techniques.(VC)

  6. Geochemical characterisation of pyrite oxidation and environmental problems related to release and transport of metals from a coal washing low-grade waste dump, Shahrood, northeast Iran.

    PubMed

    Doulati Ardejani, Faramarz; Jodieri Shokri, Behshad; Moradzadeh, Ali; Shafaei, Seyed Ziadin; Kakaei, Reza

    2011-12-01

    Pyrite oxidation and release of the oxidation products from a low-grade coal waste dump to stream, groundwater and soil was investigated by geochemical and hydrogeochemical techniques at Alborz Sharghi coal washing plant, Shahrood, northeast Iran. Hydrogeochemical analysis of water samples indicates that the metal concentrations in the stream waters were low. Moreover, the pH of the water showed no considerable change. The analysis of the stream water samples shows that except the physical changes, pyrite oxidation process within the coal washing waste dump has not affected the quality of the stream water. Water type was determined to be calcium sulphate. The results of the analysis of groundwater samples indicate that the pH varies from 7.41 to 7.51. The concentrations of the toxic metals were low. The concentration of SO4 is slightly above than its standard concentration in potable water. It seems that the groundwater less affected by the coal washing operation in the study area. Geochemical analysis of the sediment samples shows that Fe concentration decreases gradually downstream the waste dump with pH rising. SO(4) decreases rapidly downstream direction. Copper, Zn and Co concentrations decrease with distance from the waste dump due to a dilution effect by the mixing of uncontaminated sediments. These elements, in particular, Zn are considerably elevated in sediment sample collected at the nearest distance to the waste dump. There is no doubt that such investigations can help to develop an appropriate water remediation plan.

  7. Natural selection of PAH-degrading bacterial guilds at coal-tar disposal sites

    SciTech Connect

    Ghiorse, W.C.; Herrick, J.B.; Sandoli, R.L.; Madsen, E.L.

    1995-06-01

    Microbial activity patterns at buried coal-tar disposal sites have been under investigation for several years to determine the response of naturally occurring microflora to polycyclic aromatic hydrocarbons (PAHs) at the sites. At one site in upstate New York, data have shown enrichment of PAH-degrading bacteria in subsurface contaminated zones but not in uncontaminated zones. Similar work at a Midwestern site showed that the same trends existed in a heterogeneous disposal site except that a borehole outside the plume showed some PAH-mineralization activity. Polymerase chain reaction amplification of DNA extracted from sediment samples from the New York site indicated the presence of naphthalene metabolism genes nahAc and nahR, similar to those found on the NAH7 plasmid of Pseudomonas putida G7. Significant sequence polymorphism was observed in amplified nahAc products, indicating that divergent homologs of nahAc were present in the native community. Protozoan numbers were elevated in sediment samples displaying relatively high PAH-degrading activity, suggesting that a food chain was established based on PAH-degrading bacteria. Removal of the coal-tar source at the site occurred in 1991. In 1992, sampling of three key borehole stations revealed that mixing and backfilling operations had introduced soil microorganisms into the source area and introduced 14C-PAH-mineralization activity into the previously inactive pristine area. Thus removal of the source of the contaminants and restoration at the site have altered the microbial activity patterns outside the contaminant plume as well as in the source area. 15 refs., 3 figs.

  8. Metallization of oxide-ore-containing wastes with the use of brown coal semicoke from Berezovsky deposit of the Kansk- Achinsk Basin

    NASA Astrophysics Data System (ADS)

    Anikin, A. E.; Galevsky, G. V.; Nozdrin, E. V.; Rudneva, V. V.; Galevsky, S. G.

    2016-09-01

    The research of the metallization process of the roll scale and sludge after gas treatment in the BOF production with the use of brown coal semicoke mined in Berezovsky field of the Kansk-Achinsk Basin was carried out. A flow diagram of “cold” briquetting using a water-soluble binder was offered. The reduction of iron from its oxide Fe2O3 with brown coal semicoke in the laboratory electric-tube furnace in the argon atmosphere was studied. The mathematical models of dependence of the metallization degree on variable factors were developed. The optimal values of technological factors and essential characteristics of the obtained metallized products were revealed.

  9. Geologic setting and water quality of selected basins in the active coal-mining areas of Ohio, 1987-88

    USGS Publications Warehouse

    Sedam, A.C.

    1991-01-01

    This report presents hydrologic data from selected drainage basins in the active coal-mining areas of Ohio from July 1987 through October 1988. The study area is mostly within the unglaciated part of eastern Ohio along the western edge of the Appalachian Plateaus physiographic province. The 1987-88 work is the second phase of a 7-year study to assess baseline water quality in Ohio's coal region. The data collection network consisted of 41 long-term surface-water sites in 21 basins. The sites were measured and sampled twice yearly at low flow. In addition, six individual basins (three each year) selected for a more detailed representation of surface-water and ground-water quality. In 1987, the Sandy Creek, Middle Tuscarawas River and Sugar Creek, and Lower Tuscarawas River basins were chosen. In 1988, the Short and Wheeling Creeks, Upper Wills Creek, and Upper Raccoon Creek basins were chosen. Because of their proximity to the glaciated region and outwash drainage, the basins studied intensively in 1987 contain more shallow productive aquifers than do the basins studied in detail for 1988, in which shallow ground-water sources are very localized. Chemical analyses for 202 surface-water and 24 ground-water samples are presented. For field measurements made at surface-water sites, the specific conductance ranged from 295 to 3150 ? S/cm (microsiemens per centimeter at 25 degrees Celsius). For pH, the range was 2.8 to 8.6. Alkalinity ranged from 5 to 305 mg/L (milligrams per liter) as CaCO3.

  10. Continuous coal processing method

    NASA Technical Reports Server (NTRS)

    Ryason, P. R. (Inventor)

    1980-01-01

    A coal pump is provided in which solid coal is heated in the barrel of an extruder under pressure to a temperature at which the coal assumes plastic properties. The coal is continuously extruded, without static zones, using, for example, screw extrusion preferably without venting through a reduced diameter die to form a dispersed spray. As a result, the dispersed coal may be continuously injected into vessels or combustors at any pressure up to the maximum pressure developed in the extrusion device. The coal may be premixed with other materials such as desulfurization aids or reducible metal ores so that reactions occur, during or after conversion to its plastic state. Alternatively, the coal may be processed and caused to react after extrusion, through the die, with, for example, liquid oxidizers, whereby a coal reactor is provided.

  11. Kinetics of methane oxidation in selected mineral soils

    NASA Astrophysics Data System (ADS)

    Walkiewicz, A.; Bulak, P.; Brzeziñska, M.; Włodarczyk, T.; Polakowski, C.

    2012-10-01

    The kinetic parameters of methane oxidation in three mineral soils were measured under laboratory conditions. Incubationswere preceded by a 24-day preincubationwith 10%vol. of methane. All soils showed potential to the consumption of added methane. None of the soils, however, consumed atmospheric CH4. Methane oxidation followed the Michaelis-Menten kinetics, with relatively low values of parameters for Eutric Cambisol, while high values for Haplic Podzol, and especially for Mollic Gleysol which showed the highest methanotrophic activity and much lower affinity to methane. The high values of parameters for methane oxidation are typical for organic soils and mineral soils from landfill cover. The possibility of the involvement of nitrifying microorganisms, which inhabit the ammonia-fertilized agricultural soils should be verified.

  12. Colour and toxic characteristics of metakaolinite-hematite pigment for integrally coloured concrete, prepared from iron oxide recovered from a water treatment plant of an abandoned coal mine

    NASA Astrophysics Data System (ADS)

    Sadasivam, Sivachidambaram; Thomas, Hywel Rhys

    2016-07-01

    A metakaolinite-hematite (KH) red pigment was prepared using an ocherous iron oxide sludge recovered from a water treatment plant of an abandoned coal mine. The KH pigment was prepared by heating the kaolinite and the iron oxide sludge at kaolinite's dehydroxylation temperature. Both the raw sludge and the KH specimen were characterised for their colour properties and toxic characteristics. The KH specimen could serve as a pigment for integrally coloured concrete and offers a potential use for the large volumes of the iron oxide sludge collected from mine water treatment plants.

  13. Facile preparation of highly-dispersed cobalt-silicon mixed oxide nanosphere and its catalytic application in cyclohexane selective oxidation

    PubMed Central

    2011-01-01

    Highly dispersed cobalt-silicon mixed oxide [Co-SiO2] nanosphere was successfully prepared with a modified reverse-phase microemulsion method. This material was characterized in detail by X-ray diffraction, transmission electron microscopy, Fourier transform infrared, ultraviolet-visible diffuse reflectance spectra, X-ray absorption spectroscopy near-edge structure, and N2 adsorption-desorption measurements. High valence state cobalt could be easily obtained without calcination, which is fascinating for the catalytic application for its strong oxidation ability. In the selective oxidation of cyclohexane, Co-SiO2 acted as an efficient catalyst, and good activity could be obtained under mild conditions. PMID:22067075

  14. Dairy Biomass-Wyoming Coal Blends Fixed Gasification Using Air-Steam for Partial Oxidation

    DOE PAGES

    Gordillo, Gerardo; Annamalai, Kalyan

    2012-01-01

    Concenmore » trated animal feeding operations such as dairies produce a large amount of manure, termed as dairy biomass (DB), which could serve as renewable feedstock for thermal gasification. DB is a low-quality fuel compared to fossil fuels, and hence the product gases have lower heat content; however, the quality of gases can be improved by blending with coals. This paper deals with air-steam fixed-bed counterflow gasification of dairy biomass-Wyoming coal blend (DBWC). The effects of equivalence ratio ( 1.6 < Φ < 6.4 ) and steam-to-fuel ratio ( 0.4 < S : F < 0.8 ) on peak temperatures, gas composition, gross heating value of the products, and energy recovery are presented. According to experimental results, increasing Φ and ( S : F ) ratios decreases the peak temperature and increases the H 2 and CO 2 production, while CO production decreases. On the other hand, the concentrations of CH 4 and C 2 H 6 were lower compared to those of other gases and almost not affected by Φ.« less

  15. Bio-oxidation of thiocyanates typical of coal conversion effluents. Final report

    SciTech Connect

    Neufeld, R. D.; Mattson, L.; Lubon, P.

    1981-01-08

    Thiocyanates have been found in most coal conversion and coke plant effluents. The objectives of this study were to develop data for the biological degradation fate kinetics of thiocyanate removal, and to develop material balance information for the fate of sulfur and nitrogen resulting from such bio-decomposition of aqueous thiocyanates. A literature review of thiocyanate bio-degradation indicates that while much biochemistry information is available, little information in the biological processing arena is known. Based on both batch and continuous culture experiments utilizing an activated sludge type of system with strictly thiocyanate degradating organisms, the specific utilization rate for SCN degradation was found to follow a substrate inhibition biokinetic relationship as: d(SCN)/dt-X = 2.24/(1 + (5/SCN) + (SCN/1340)/sup 6/) where; d(SCN)/dt-X = lb SCN used/lb biomass-day, SCN = mg/L SCN in effluent. The observed biomass sludge production rate was quantified as a function of sludge age in the bio-reactor. The major metabolic by-products of SCN aerobic biodegradation are ammonia and sulfate, with such formation being stochiometric with SCN. High levels of SCN in coal conversion and Stretford system effluents may lead to biological nitrification process requirements to be added to the wastetreatment scheme for compliance with BAT effluent ammonia discharge restrictions.

  16. Fabrication of Fe-Al nanoparticles by selective oxidation of Fe-Al thin films

    NASA Astrophysics Data System (ADS)

    Jang, Pyungwoo; Shin, Seungchan; Jung, Chip-Sup; Kim, Kwang-Ho; Seomoon, Kyu

    2013-04-01

    The possibility of a new technique for fabricating nanoparticles from thin films using selective oxidation in an atmosphere mixture of water vapor and hydrogen was investigated. Fe-5wt.%Al films were RF-sputtered and annealed in the atmosphere mixture at 900°C for up to 200 min, in order to oxidize aluminum selectively. Thermodynamics simulation showed that temperatures exceeding 800°C are necessary to prevent iron from being oxidized, as confirmed by the depth profile of XPS. As the annealing time increased, the morphology of the 200-nm Fe-Al films changed from the continuous to the discontinuous type; thus, particulate Fe-Al films formed after 100 min. The particulate 10- to 100-nm Fe-Al films showed super-paramagnetic behavior after the oxidation. Thus, a new technique for fabricating nanoparticles was successfully introduced using selective oxidation.

  17. [Current research situation of H2S selective catalytic oxidation technologies and catalysts].

    PubMed

    Hao, Zheng-ping; Dou, Guang-yu; Zhang, Xin; Qu, Si-qiu

    2012-08-01

    This review summarizes and discusses different selective catalytic oxidation technologies and various catalysts for removing H2S, the undesirable byproduct of the fluid catalytic cracking (FCC) processing. Currently the selective oxidation technologies used include Superclaus, Euroclaus, Clinsulf-Do, BSR/Hi-Activity, Selectox and Modop techniques, which have various characteristics and application areas. Catalysts for H2S selective oxidation mainly contain the following systems: carbon, supported SiC, zeolite, oxide, and pillared clay. Former studies focused on carbon and oxide systems. The research interest on zeolite system decreased in recent years, while SiC is regarded as a typical support with great potential for this reaction and continues to be attractive. Pillared clay system is at the preliminary research stage, and is still far from practical application.

  18. Selective oxidation of cyclohexane on a novel catalyst Mg-Cu/SBA-15 by molecular oxygen.

    PubMed

    Duan, Xiaogang; Liu, Weimin; Yue, Lumin; Fu, Wei; Ha, Minh Ngoc; Li, Jun; Lu, Guanzhong

    2015-10-21

    The novel catalysts xMg-2.3Cu/SBA-15 with copper and magnesium oxide co-supported on mesoporous silica were synthesized by an impregnation method. The newly synthesized catalysts were characterized using a series of techniques such as BET, XRD, H2-TPR, UV-vis, XPS, EDS and TEM. The catalytic performance was evaluated by using selective oxidation of cyclohexane with molecular oxygen as the oxidant in a solvent free system. The incorporation of magnesium improved the dispersion of copper oxide and prevented the deep oxidation of cyclohexanol and cyclohexanone. The selectivity of K/A oil was up to 99.3% with 12% conversion of cyclohexane over the 1.2Mg-2.3Cu/SBA-15 catalyst. To our knowledge, this is the best result for the heterogeneous oxidation of cyclohexane by O2. PMID:26388454

  19. Engineering development of coal-fired high performance power systems, Phase 2: Selective non-catalytic reduction system development

    SciTech Connect

    1997-02-24

    Most of the available computational models for Selective Non- Catalytic Reduction (SNCR) systems are capable of identifying injection parameters such as spray droplet size, injection angles and velocity. These results allow identification of the appropriate injection locations based on the temperature window and mixing for effective dispersion of the reagent. However, in order to quantify No{sub x} reduction and estimate the potential for ammonia slip, a kinetic model must be coupled with the mixing predictions. Typically, reaction mechanisms for SNCR consist of over 100 elementary steps occurring between approximately 30 different species. Trying to model a mechanism of this size is not practical. This ABB project incorporated development of SNCR systems including NO{sub x} reduction and ammonia slip. The model was validated using data collected from a large-scale experimental test facility. The model developed under this project can be utilized for the SNCR system design applicable to HIPPS. The HITAF design in the HIPPS project includes low NO{sub x} firing system in the coal combustor and both selective non-catalytic reduction (SNCR) downstream of the radiant heating section and selective catalytic reduction in a lower temperature zone. The performance of the SNCR will dictate the capacity and capital cost requirements of the SCR.

  20. Catalytic Destruction of a Surrogate Organic Hazardous Air Pollutant as a Potential Co-benefit for Coal-fired Selective Catalyst Reduction Systems

    EPA Science Inventory

    Catalytic destruction of benzene (C6H6), a surrogate for organic hazardous air pollutants (HAPs) produced from coal combustion, was investigated using a commercial selective catalytic reduction (SCR) catalyst for evaluating the potential co-benefit of the SCR technology for reduc...

  1. SUPERCRITICAL WATER OXIDATION MODEL DEVELOPMENT FOR SELECTED EPA PRIORITY POLLUTANTS

    EPA Science Inventory

    Supercritical Water Oxidation (SCWO) evaluated for five compounds: acetic acid, 2,4-dichlorophenol, pentachlorophenol, pyridine, 2,4-dichlorophenoxyacetic acid (methyl ester). inetic models were developed for acetic acid, 2,4-dichlorophenol, and pyridine. he test compounds were e...

  2. Regenerable cobalt oxide loaded magnetosphere catalyst from fly ash for mercury removal in coal combustion flue gas.

    PubMed

    Yang, Jianping; Zhao, Yongchun; Zhang, Junying; Zheng, Chuguang

    2014-12-16

    To remove Hg(0) in coal combustion flue gas and eliminate secondary mercury pollution of the spent catalyst, a new regenerable magnetic catalyst based on cobalt oxide loaded magnetospheres from fly ash (Co-MF) was developed. The catalyst, with an optimal loading of 5.8% cobalt species, attained approximately 95% Hg(0) removal efficiency at 150 °C under simulated flue gas atmosphere. O2 could enhance the Hg(0) removal activity of magnetospheres catalyst via the Mars-Maessen mechanism. SO2 displayed an inhibitive effect on Hg(0) removal capacity. NO with lower concentration could promote the Hg(0) removal efficiency. However, when increasing the NO concentration to 300 ppm, a slightly inhibitive effect of NO was observed. In the presence of 10 ppm of HCl, greater than 95.5% Hg(0) removal efficiency was attained, which was attributed to the formation of active chlorine species on the surface. H2O presented a seriously inhibitive effect on Hg(0) removal efficiency. Repeated oxidation-regeneration cycles demonstrated that the spent Co-MF catalyst could be regenerated effectively via thermally treated at 400 °C for 2 h.

  3. Mathematical modeling of the kinetics of carbothermic reduction of iron oxides in ore-coal composite pellets

    SciTech Connect

    Sun, K.; Lu, W.K.

    2009-02-15

    The kinetics of the carbothermic reduction of iron oxides in a composite pellet made of taconite concentrate and high-volatility coal has been studied by means of mathematical modeling that simultaneously takes into account the transfer rates of both the mass and the heat, and the rates of chemical reactions. The computational results, which have been validated with experimental data in the literature, confirm that the overall rate of the carbothermic reduction, which is strongly endothermic, is limited by heat-transfer steps. From a kinetics viewpoint, the optimum composition of the composite pellet is approximately in accordance with the stoichiometry, when CO is assumed to be the sole oxide of carbon in the gas. To raise the temperature of the pellet from its ambient value to furnace temperature, the heat required is greater than that needed for sustaining all chemical reactions, including the Boudouard reaction. The gaseous product consists mainly of CO and H{sub 2}, except in the very initial stage. The overall observable reaction rate, in terms of the volumetric rate of the generation of gases, peaks at approximately 30 seconds of reaction time.

  4. Regenerable cobalt oxide loaded magnetosphere catalyst from fly ash for mercury removal in coal combustion flue gas.

    PubMed

    Yang, Jianping; Zhao, Yongchun; Zhang, Junying; Zheng, Chuguang

    2014-12-16

    To remove Hg(0) in coal combustion flue gas and eliminate secondary mercury pollution of the spent catalyst, a new regenerable magnetic catalyst based on cobalt oxide loaded magnetospheres from fly ash (Co-MF) was developed. The catalyst, with an optimal loading of 5.8% cobalt species, attained approximately 95% Hg(0) removal efficiency at 150 °C under simulated flue gas atmosphere. O2 could enhance the Hg(0) removal activity of magnetospheres catalyst via the Mars-Maessen mechanism. SO2 displayed an inhibitive effect on Hg(0) removal capacity. NO with lower concentration could promote the Hg(0) removal efficiency. However, when increasing the NO concentration to 300 ppm, a slightly inhibitive effect of NO was observed. In the presence of 10 ppm of HCl, greater than 95.5% Hg(0) removal efficiency was attained, which was attributed to the formation of active chlorine species on the surface. H2O presented a seriously inhibitive effect on Hg(0) removal efficiency. Repeated oxidation-regeneration cycles demonstrated that the spent Co-MF catalyst could be regenerated effectively via thermally treated at 400 °C for 2 h. PMID:25403026

  5. Coal Combustion Science

    SciTech Connect

    Hardesty, D.R.; Fletcher, T.H.; Hurt, R.H.; Baxter, L.L. )

    1991-08-01

    The objective of this activity is to support the Office of Fossil Energy in executing research on coal combustion science. This activity consists of basic research on coal combustion that supports both the Pittsburgh Energy Technology Center Direct Utilization Advanced Research and Technology Development Program, and the International Energy Agency Coal Combustion Science Project. Specific tasks for this activity include: (1) coal devolatilization - the objective of this risk is to characterize the physical and chemical processes that constitute the early devolatilization phase of coal combustion as a function of coal type, heating rate, particle size and temperature, and gas phase temperature and oxidizer concentration; (2) coal char combustion -the objective of this task is to characterize the physical and chemical processes involved during coal char combustion as a function of coal type, particle size and temperature, and gas phase temperature and oxygen concentration; (3) fate of mineral matter during coal combustion - the objective of this task is to establish a quantitative understanding of the 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 distribution of mineral species in the unreacted coal, and the local gas temperature and composition.

  6. Selective oxidation of cyclohexanol to cyclohexanone in the ionic liquid 1-octyl-3-methylimidazolium chloride.

    PubMed

    Chen, Long; Zhou, Teng; Chen, Lifang; Ye, Yinmei; Qi, Zhiwen; Freund, Hannsjörg; Sundmacher, Kai

    2011-09-01

    Ionic liquid (IL) 1-octyl-3-methylimidazolium chloride was found to effectively intensify cyclohexanol oxidation and resulted in 100% conversion of cyclohexanol with 100% selectivity to cyclohexanone using hydrogen peroxide as an oxidant and WO(3) as a catalyst. The effect of the IL as a solvent is discussed with the support of COSMO-RS theory.

  7. Cu and Boron Doped Carbon Nitride for Highly Selective Oxidation of Toluene to Benzaldehyde.

    PubMed

    Han, Hongling; Ding, Guodong; Wu, Tianbin; Yang, Dexin; Jiang, Tao; Han, Buxing

    2015-07-13

    A novel Cu and boron doped graphitic carbon nitride catalyst (Cu-CNB) was synthesized using cheap precursors and systematically characterized. The selective oxidation of toluene proceeded very smoothly over the catalyst at 70 °C using tert-butyl hydroperoxide (TBHP) as the oxidant to exclusively afford benzaldehyde. The catalyst can be used for at least five cycles without decrease in activity and selectivity.

  8. Selective Oxidation of Methionine and Tryptophan Residues in a Therapeutic IgG1 Molecule.

    PubMed

    Folzer, Emilien; Diepold, Katharina; Bomans, Katrin; Finkler, Christof; Schmidt, Roland; Bulau, Patrick; Huwyler, Jörg; Mahler, Hanns-Christian; Koulov, Atanas V

    2015-09-01

    Oxidation of methionine and tryptophan are common degradation pathways for monoclonal antibodies and present major analytical challenges in biotechnology. Generally, protein oxidation is detectable in stability and/or stressed samples (e.g., exposed to hydrogen peroxide, UV light, or metal ions). The induced chemical modifications may impact the biological activity of antibodies and may have biological consequences. However, these effects and the contribution of individual protein modifications are difficult to delineate as different amino acids are often oxidized simultaneously and accompanied by other degradants such as aggregates, especially in forced degradation studies. Here, we report a new method to obtain selective oxidation of methionine or tryptophan by using oxidation reagents combined with large excess of free tryptophan or methionine, correspondingly. More specifically, using hydrogen peroxide or tert-butyl hydroperoxide in combination with addition of free tryptophan allowed for selective oxidation of methionine. Conversely, the use of 2,2-azobis(2-amidinopropane) dihydrochloride in combination with free methionine resulted in selective tryptophan oxidation, whereas methionine oxidation was not significantly altered. This novel stress model system may prove to be valuable tool in future mechanistic studies of oxidative degradation of protein therapeutics.

  9. Hydrology of Selected Basins in the Warrior Coal Field, Alabama - A Progress Report

    USGS Publications Warehouse

    Puente, Celso; Newton, John G.; Hill, Thomas J.

    1980-01-01

    Hydrologic data are being collected in four basins in the Warrior coal field in Alabama to provide baseline information to aid in determining the effect mining will have on water resources. Basins monitored are in two different geologic and hydrologic environments. Two basins are underlain predominantly by relatively impermeable indurated rocks in the Pottsville Formation of Pennsylvanian age. The two remaining basins are underlain predominantly by unconsolidated permeable rocks in the Coker Formation of Late Cretaceous age. Well yields from the Pottsville Formation generally range from 0 to 0.3 liter per second, whereas well yields from the Coker Formation generally range form 0.3 to 6.4 liters per second. Streamflow distribution reflects seasonal precipitation. Storm runoff is characterized by sharply concentrated flows of short duration that rapidly recede to low-flow conditions. Streams draining basins underlain chiefly by the Pottsville Formation frequently go dry, whereas those draining basins underlain chiefly by the Coker Formation have well sustained low flows. Water in the Pottsville Formation is slightly acidic and moderately hard to very hard. Dissolved solids concentrations ranged from 176 to 268 milligrams per liter. Water in the Coker Formation is soft, far less mineralized, and more acidic than water in the Pottsville. Surface water is generally soft, acidic and low in dissolved solids concentrations. Water in streams draining basins underlain chiefly by the Pottsville Formation was slightly more mineralized and less acidic than water in streams draining the Coker Formation. (USGS)

  10. Heavy metals in wild house mice from coal-mining areas of Colombia and expression of genes related to oxidative stress, DNA damage and exposure to metals.

    PubMed

    Guerrero-Castilla, Angélica; Olivero-Verbel, Jesús; Marrugo-Negrete, José

    2014-03-01

    Coal mining is a source of pollutants that impact on environmental and human health. This study examined the metal content and the transcriptional status of gene markers associated with oxidative stress, metal transport and DNA damage in livers of feral mice collected near coal-mining operations, in comparison with mice obtained from a reference site. Mus musculus specimens were caught from La Loma and La Jagua, two coal-mining sites in the north of Colombia, as well as from Valledupar (Cesar Department), a city located 100km north of the mines. Concentrations in liver tissue of Hg, Zn, Pb, Cd, Cu and As were determined by differential stripping voltammetry, and real-time PCR was used to measure gene expression. Compared with the reference group (Valledupar), hepatic concentrations of Cd, Cu and Zn were significantly higher in animals living near mining areas. In exposed animals, the mRNA expression of NQ01, MT1, SOD1, MT2, and DDIT3 was 4.2-, 7.3-, 2.5-, 4.6- and 3.4-fold greater in coal mining sites, respectively, than in animals from the reference site (p<0.05). These results suggest that activities related to coal mining may generate pollutants that could affect the biota, inducing the transcription of biochemical markers related to oxidative stress, metal exposure, and DNA damage. These changes may be in part linked to metal toxicity, and could have implications for the development of chronic disease. Therefore, it is essential to implement preventive measures to minimize the effects of coal mining on its nearby environment, in order to protect human health.

  11. Shape control of AlGaAs selective oxidation by intermixing method

    NASA Astrophysics Data System (ADS)

    Gi, Tetsu; Miyamoto, Tomoyuki

    2016-11-01

    Shape control of AlGaAs selective oxidation regions by heterointerface intermixing was investigated. The oxidation rate dependence on the intermixing conditions was characterized. Under 880 °C with three hours of intermixing, the oxidation rate was reduced to half that of the usual oxidation without intermixing. The thicknesses of a GaAs capping layer and a deposited SiO2 layer affected the oxidation rate. A detailed analysis of the oxidation after intermixing was carried out by scanning transmission electron microscopy (STEM) measurement. On the basis of the oxidation characteristics with intermixing, in-plane shape control was demonstrated. This result will be helpful in the fabrication of complicated device shapes.

  12. Levels of Exhaled Breath Condensate pH and Fractional Exhaled Nitric Oxide in Retired Coal Miners.

    PubMed

    Lee, Jong Seong; Shin, Jae Hoon; Lee, Joung Oh; Lee, Kyung Myung; Kim, Ji Hong; Choi, Byung-Soon

    2010-12-01

    Inhaled inorganic dusts, such as coal, can cause inflammation and fibrosis in the lungs, known as pneumoconiosis. Diagnosis of pneumoconiosis depends on morphological changes by radiological findings and functional change by pulmonary function test (PFT) . Unfortunately, current diagnostic findings are limited only to lung fibrosis, which is usually irreversibly progressive. Therefore, it is important that research on potential and prospective biomarkers for pneumoconiosis should be conducted prior to initiation of irreversible radiological or functional changes in the lungs. Analytical techniques using exhaled breath condensate (EBC) or exhaled gas are non-invasive methods for detection of various respiratory diseases. The objective of this study is to investigate the relationship between inflammatory biomarkers, such as EBC pH or fractional exhaled nitric oxide (FENO) , and pneumoconiosis among 120 retired coal miners (41 controls and 79 pneumoconiosis patients) . Levels of EBC pH and FENO did not show a statistically significant difference between the pneumoconiosis patient group and pneumoconiosis patients with small opacity classified by International Labor Organization (ILO) classification. The mean concentration of FENO in the low percentage FEV1 (< 80%) was lower than that in the high percentage (80% ≤) (p = 0.023) . The mean concentration of FENO in current smokers was lower than that in non smokers (never or past smokers) (p = 0.027) . Although there was no statistical significance, the levels of FENO in smokers tended to decrease, compared with non smokers, regardless of pneumoconiosis. In conclusion, there was no significant relationship between the level of EBC pH or FENO and radiological findings or PFT. The effects between exhaled biomarkers and pneumoconiosis progression, such as decreasing PFT and exacerbation of radiological findings, should be monitored. PMID:24278541

  13. Fluidized Bed Selective Oxidation-Sulfation Roasting of Nickel Sulfide Concentrate: Part I. Oxidation Roasting

    NASA Astrophysics Data System (ADS)

    Yu, Dawei; Utigard, Torstein A.; Barati, Mansoor

    2014-04-01

    Two-stage oxidation-sulfation roasting of nickel sulfide concentrate in fluidized bed was investigated to generate water-soluble metal sulfates as an alternative process to smelting of the sulfide concentrate for the recovery of valuable metals. The first stage, i.e., oxidation roasting, was employed to preferentially oxidize the iron before performing sulfation roasting. A batch fluidized bed roaster was constructed for roasting tests. Roasting products from various roasting temperatures and different roasting times were analyzed by SEM/EDS, EPMA, XRD, and ICP-OES to investigate the oxidation roasting behavior of the nickel concentrate as a function of temperature and time.

  14. Selective heterocyclic amidine inhibitors of human inducible nitric oxide synthase.

    PubMed

    Moormann, A E; Metz, S; Toth, M V; Moore, W M; Jerome, G; Kornmeier, C; Manning, P; Hansen, D W; Pitzele, B S; Webber, R K

    2001-10-01

    The potency and selectivity of a series of 5-hetero-2-iminohexahydroazepines were examined as inhibitors of the three human NOS isoforms. The effect of ring substitution of the 5-carbon for a heteroatom is presented. Potencies (IC(50)'s) for these inhibitors are in the low micromolar range for hi-NOS with some examples exhibiting a 500x selectivity versus hec-NOS.

  15. Oxidation of electrodeposited black chrome selective solar absorber films

    SciTech Connect

    Holloway, P.H.; Shanker, K.; Pettit, R.B.; Sowell, R.R.

    1980-01-01

    X-ray photoelectron and Auger electron spectroscopies have been used to study the composition and oxidation of electrodeposited black chrome films. The outer layer of the film is Cr/sub 2/O/sub 3/ with the inner layer being a continuously changing mixture of Cr + Cr/sub 2/O/sub 3/. Initially, approximately 40% by volume of the film is combined as Cr/sub 2/O/sub 3/, and the volume percentage of Cr/sub 2/O/sub 3/ increases to greater than 60% after only 136 hours at 250/sup 0/C. After approximately 3600 hours at 400/sup 0/C, the volume percentage of Cr/sub 2/O/sub 3/ increased to as high as 80%. The thermal emittance decreased approximately linearly with increasing oxide content, while the solar absorptance remained constant until the percentage of Cr/sub 2/O/sub 3/ exceeded approximately 70%. Oxidation was slower when the Cr/sup +3/ concentration in the plating bath was reduced from 16 g/l to 8 g/l, and when black chrome was deposited on stainless steel rather than sulfamate nickel.

  16. Evaluating the combustion reactivity of drop tube furnace and thermogravimetric analysis coal chars with a selection of metal additives

    SciTech Connect

    Katherine Le Manquais; Colin E. Snape; Ian McRobbie; Jim Barker

    2011-03-17

    Opportunities exist for effective coal combustion additives that can reduce the carbon content of pulverized fuel ash (PFA) to below 6%, thereby making it saleable for filler/building material applications without the need for postcombustion treatment. However, with only limited combustion data currently available for the multitude of potential additives, catalytic performance under pulverized fuel (PF) boiler conditions has received relatively little attention. This paper therefore compares the reactivity of catalyzed bituminous coal chars from thermogravimetric analysis (TGA) with those generated by devolatilization in a drop tube furnace (DTF). The principal aim was to explore the fundamental chemistry behind the chosen additives' relative reactivities. Accordingly, all eight of the investigated additives increased the TGA burnout rate of the TGA and DTF chars, with most of the catalysts demonstrating consistent reactivity levels across chars from both devolatilization methods. Copper(I) chloride, silver chloride, and copper nitrate were thus identified as the most successful additives tested, but it proved difficult to establish a definitive reactivity ranking. This was largely due to the use of physical mixtures for catalyst dispersion, the relatively narrow selection of additives examined, and the inherent variability of the DTF chars. Nevertheless, one crucial exception to normal additive behavior was discovered, with copper(I) chloride perceptibly deactivating during devolatilization in the DTF, even though it remained the most effective catalyst tested. As a prolonged burnout at over 1000{sup o}C was required to replicate this deactivation effect on the TGA, the phenomenon could not be detected by typical testing procedures. Subsequently, a comprehensive TGA study showed no obvious relationship between the catalyst-induced reductions in the reaction's apparent activation energy and the samples recorded burnout rates.

  17. Impact of blend ratio on the co-firing of a commercial torrefied biomass and coal via analysis of oxidation kinetics.

    PubMed

    Goldfarb, Jillian L; Liu, Chao

    2013-12-01

    Incorporation of torrefied biomass into coal-fired power plants could potentially lower the SOx and net CO2 emissions resulting from electricity generation. However, concerns over lower heating values and slightly higher ash content of torrefied biomass suggest that blending it with coal in industrial boilers may be preferable to complete fuel transition. By studying the oxidation kinetics of coal-torrefied biomass blends in a thermogravimetric analyzer at a heating rate of 100°C/min, we find an additive nature among the fuels for peak mass loss rates and enthalpies of combustion. The activation energy required to initiate decomposition decreases from 132.6 to 77.6 kJ/mol as the torrefied biomass increases from 0 to 100 wt%, with a sharp decrease between 0 and 40 wt%. Data suggest that incorporation of torrefied biomass into coal-fired boilers is dependent on the ability to sacrifice heating value for the lower emissions of SOx and net CO2 garnered using bio-coal.

  18. Supported, Alkali-Promoted Cobalt Oxide Catalysts for NOx Removal from Coal Combustion Flue Gases

    SciTech Connect

    Morris D. Argyle

    2005-12-31

    A series of cobalt oxide catalysts supported on alumina ({gamma}-Al{sub 2}O{sub 3}) were synthesized with varying contents of cobalt and of added alkali metals, including lithium, sodium, potassium, rubidium, and cesium. Unsupported cobalt oxide catalysts and several cobalt oxide catalysts supported ceria (CeO{sub 2}) with varying contents of cobalt with added potassium were also prepared. The catalysts were characterized with UV-visible spectroscopy and were examined for NO{sub x} decomposition activity. The CoO{sub x}/Al{sub 2}O{sub 3} catalysts and particularly the CoO{sub x}/CeO{sub 2} catalysts show N{sub 2}O decomposition activity, but none of the catalysts (unsupported Co{sub 3}O{sub 4} or those supported on ceria or alumina) displayed significant, sustained NO decomposition activity. For the Al{sub 2}O{sub 3}-supported catalysts, N{sub 2}O decomposition activity was observed over a range of reaction temperatures beginning about 723 K, but significant (>50%) conversions of N{sub 2}O were observed only for reaction temperatures >900 K, which are too high for practical commercial use. However, the CeO{sub 2}-supported catalysts display N{sub 2}O decomposition rates similar to the Al{sub 2}O{sub 3}-supported catalysts at much lower reaction temperatures, with activity beginning at {approx}573 K. Conversions of >90% were achieved at 773 K for the best catalysts. Catalytic rates per cobalt atom increased with decreasing cobalt content, which corresponds to increasing edge energies obtained from the UV-visible spectra. The decrease in edge energies suggests that the size and dimensionality of the cobalt oxide surface domains increase with increasing cobalt oxide content. The rate data normalized per mass of catalyst that shows the activity of the CeO{sub 2}-supported catalysts increases with increasing cobalt oxide content. The combination of these data suggest that supported cobalt oxide species similar to bulk Co{sub 3}O{sub 4} are inherently more active than

  19. Selective coal mine overburden treatment with topsoil and compost to optimise pasture or native vegetation establishment.

    PubMed

    Spargo, A; Doley, D

    2016-11-01

    Overburden at a coal mine in the Hunter Valley, New South Wales, was stored in a flat-topped artificial mound with 14-degree side slopes. Topsoil was scarce, dispersive and readily eroded. A split-plot factorial experiment applied an enhanced municipal solid waste compost at 0, 60 or 100 t ha(-1) to untreated overburden or to overburden covered with 0.1 m of topsoil. Two seeding treatments, of trees and shrubs or of pasture species, were applied to two 0.5-ha replicates of each surface treatment. Substrate physical and chemical properties and vegetation attributes were assessed 2.5 years later. Compost application to both topsoil and overburden significantly increased total N, P, Cu and Zn, soluble K, Ca and Mg, and significantly reduced soluble Na and pH. Mean tree density, size and total canopy cover were significantly greater with compost applied at 60 t ha(-1) to overburden than with all other treatments, especially those on topsoil where tree growth was inhibited by undesired species. Compost application to overburden and topsoil at 100 t ha(-1) significantly increased biomass of desired pasture species and significantly reduced undesired species cover compared with unamended topsoil and the extent of bare ground compared with unamended overburden. Successful development of woody species on overburden and pastures on both overburden and topsoil treated with compost provides opportunities for new combinations of landscape design, surface preparation and plant species introductions to increase the stability of final landforms, the effectiveness of resource use, and the delivery of commercial and biodiversity benefits from mine site rehabilitation. PMID:27497311

  20. Counteraction of poly(4-vinylpyridine-n-oxide) on the depression of viral interferon induction by coal dust.

    PubMed Central

    Hahon, N

    1976-01-01

    The depressive activity of coal dust on interferon induction by influenza was markedly subverted when either coal dust or LLC-MK2 cell monolayers were pretreated with poly (4-vinylpyridine-N-oside). The polymer alone neither induced interferon synthesis, inhibited viral induction of interferon, influenced viral multiplication, nor affected cellular-induced resistance by interferon. Absorption of the polymer to coal dust not only occurred at a more rapid rate than to cell monolayers, but also less polymer was required to pretreat coal dust than cell monolayers to achieve comparable amelioration of interferon production. The polymer effectively negated the adverse activity of coal dust particles, irrespective of the latter's size (is less than 2.0 to 74.0 mum). Virus multiplication in the presence of coal dust=treated cell monolayers attained a level that was twofol higher than that noted with either polymer-pretreated coal dust or polymer-pretreated cell monolayers. Interferon production was almost completely inhibited in the presence of coal dust; pretreating coal dust or cells with the polymer abrogated this inhibitory activity of coal dust. It is tentatively suggested that coal dust particles per se directly interact with cell membranes to subvert interferon induction and that the formation of an absorbed polymerlayer on these complexes prevents their interaction. PMID:178603

  1. The influence of selected parameters on the efficiency and economic charactersistics of the oxy-type coal unit with a membrane-cryogenic oxygen separator

    NASA Astrophysics Data System (ADS)

    Kotowicz, Janusz; Berdowska, Sylwia

    2016-03-01

    In this paper a 600 MW oxy-type coal unit with a pulverized bed boiler and a membrane-cryogenic oxygen separator and carbon capture installation was analyzed. A membrane-cryogenic oxygen separation installation consists of a membrane module and two cryogenic distillation columns. In this system oxygen is produced with the purity equal to 95%. Installation of carbon capture was based on the physical separation method and allows to reduce the CO2 emission by 90%. In this work the influence of the main parameter of the membrane process - the selectivity coefficient, on the efficiency of the coal unit was presented. The economic analysis with the use of the break-even point method was carried out. The economic calculations were realized in view of the break-even price of electricity depending on a coal unit availability.

  2. An assessment of zinc oxide nanosheets as a selective adsorbent for cadmium

    PubMed Central

    2013-01-01

    Zinc oxide nanosheet is assessed as a selective adsorbent for the detection and adsorption of cadmium using simple eco-friendly extraction method. Pure zinc oxide nanosheet powders were characterized using field emission scanning electron microscopy, energy dispersive spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and Fourier transform infrared spectroscopy. The zinc oxide nanosheets were applied to different metal ions, including Cd(II), Cu(II), Hg(II), La(III), Mn(II), Pb(II), Pd(II), and Y(III). Zinc oxide nanosheets were found to be selective for cadmium among these metal ions when determined by inductively coupled plasma-optical emission spectrometry. Moreover, adsorption isotherm data provided that the adsorption process was mainly monolayer on zinc oxide nanosheets. PMID:24011201

  3. Superior catalysts for selective catalytic reduction of nitric oxide. Final technical report, October 1, 1993--September 30, 1995

    SciTech Connect

    Yang, R.T.; Li, W.B.; Chen, J.P.; Hausladen, M.C.; Cheng, L.S.; Kikkinides, E.S.

    1995-12-31

    The most advanced and proven technology for NO{sub x} control for stationary sources is Selective Catalytic Reduction (SCR). In SCR, NO{sub x} is reduced by NH{sub 3} to N{sub 2} and H{sub 2}O. The commercial catalysts are based on V{sub 2}O{sub 5}/TiO{sub 2}, and the vanadium-based catalysts are patented by the Japanese (Mitsubishi). However, there are three main advantages for the vanadium-based SCR catalyst: (a) a tendency to be poisoned in the flue gas; (b) oxidation of SO{sub 2} to SO{sub 3} by V{sub 2}O{sub 5}, this is a particularly severe problem due to the higher sulfur content of American coals compared with coals used in Japan (from Australia) and in Europe; (c) environmental problems involved in the disposal of the spent catalyst (due to the toxicity of vanadium). In order to overcome these problems, in addition to the undesirable dominance by the Japanese patent position, the authors have studied in this project a new type of catalyst for the SCR reaction; namely, pillared clays, which have adjustable, unique structures and acidity. Three types of catalysts were developed and tested for this reaction, i.e. Fe{sub 2}O{sub 3}-pillared clays, delaminated Fe{sub 2}O{sub 3}-pillared clays, and ion-exchanged pillared clays. The project was divided into sixteen tasks, and will be reported as such.

  4. Theoretical technique for predicting the cumulative impact of iron and manganese oxidation in streams receiving discharge from coal mines

    USGS Publications Warehouse

    Bobay, Keith E.

    1986-01-01

    Two U.S. Geological Survey computer programs are modified and linked to predict the cumulative impact of iron and manganese oxidation in coal-mine discharge water on the dissolved chemical quality of a receiving stream. The coupled programs calculate the changes in dissolved iron, dissolved manganese, and dissolved oxygen concentrations; alkalinity; and, pH of surface water downstream from the point of discharge. First, the one-dimensional, stead-state stream, water quality program uses a dissolved oxygen model to calculate the changes in concentration of elements as a function of the chemical reaction rates and time-of-travel. Second, a program (PHREEQE) combining pH, reduction-oxidation potential, and equilibrium equations uses an aqueous-ion association model to determine the saturation indices and to calculate pH; it then mixes the discharge with a receiving stream. The kinetic processes of the first program dominate the system, whereas the equilibrium thermodynamics of the second define the limits of the reactions. A comprehensive test of the technique was not possible because a complete set of data was unavailable. However, the cumulative impact of representative discharges from several coal mines on stream quality in a small watershed in southwestern Indiana was simulated to illustrate the operation of the technique and to determine its sensitivity to changes in physical, chemical, and kinetic parameters. Mine discharges averaged 2 cu ft/sec, with a pH of 6.0, and concentrations of 7.0 mg/L dissolved iron, 4.0 mg/L dissolved manganese, and 8.08 mg/L dissolved oxygen. The receiving stream discharge was 2 cu ft/sec, with a pH of 7.0, and concentrations of 0.1 mg/L dissolved iron, 0.1 mg/L dissolved manganese, and 8.70 mg/L dissolved oxygen. Results of the simulations indicated the following cumulative impact on the receiving stream from five discharges as compared with the effect from one discharge: 0.30 unit decrease in pH, 1.82 mg/L increase in dissolved

  5. Stable lead isotope compositions in selected coals from around the world and implications for present day aerosol source tracing.

    PubMed

    Díaz-Somoano, M; Kylander, M E; López-Antón, M A; Suárez-Ruiz, I; Martínez-Tarazona, M R; Ferrat, M; Kober, B; Weiss, D J

    2009-02-15

    The phasing out of leaded gasoline in many countries around the world at the end of the last millennium has resulted in a complex mixture of lead sources in the atmosphere. Recent studies suggest that coal combustion has become an important source of Pb in aerosols in urban and remote areas. Here, we report lead concentration and isotopic composition for 59 coal samples representing major coal deposits worldwide in an attempt to characterize this potential source. The average concentration in these coals is 35 microg Pb g(-1), with the highest values in coals from Spain and Peru and the lowest in coals from Australia and North America. The 206Pb/207Pb isotope ratios range between 1.15 and 1.24, with less radiogenic Pb in coals from Europe and Asia compared to South and North America. Comparing the Pb isotopic signatures of coals from this and previous studies with those published for Northern and Southern Hemisphere aerosols, we hypothesize that coal combustion might now be an important Pb source in China, the eastern U.S., and to some extent, in Europe but not as yet in other regions including South Africa, South America, and western U.S. This supports the notion that "old Pb pollution" from leaded gasoline reemitted into the atmosphere or long-range transport (i.e., from China to the western U.S.) is important. Comparing the isotope ratios of the coals, the age of the deposits, and Pb isotope evolution models for the major geochemical reservoirs suggests that the PbIC in coals is strongly influenced by the depositional coal forming environment.

  6. Stable lead isotope compositions in selected coals from around the world and implications for present day aerosol source tracing

    SciTech Connect

    M. Diaz-Somoano; M.E. Kylander; M.A. Lopez-Anton; I. Suarez-Ruiz; M.R. Martinez-Tarazona; M. Ferrat; B. Kober; D.J. Weiss

    2009-02-15

    The phasing out of leaded gasoline in many countries around the world at the end of the last millennium has resulted in a complex mixture of lead sources in the atmosphere. Recent studies suggest that coal combustion has become an important source of Pb in aerosols in urban and remote areas. Lead concentration and isotopic composition is reported for 59 coal samples representing major coal deposits worldwide in an attempt to characterize this potential source. The average concentration in these coals is 35 {mu}g Pb g{sup -1}, with the highest values in coals from Spain and Peru and the lowest in coals from Australia and North America. The {sup 206}Pb/{sup 207}Pb isotope ratios range between 1.15 and 1.24, with less radiogenic Pb in coals from Europe and Asia compared to South and North America. Comparing the Pb isotopic signatures of coals from this and previous studies with those published for Northern and Southern Hemisphere aerosols, we hypothesize that coal combustion might now be an important Pb source in China, the eastern U.S., and to some extent, in Europe but not as yet in other regions including South Africa, South America, and western U.S. This supports the notion that 'old Pb pollution' from leaded gasoline reemitted into the atmosphere or long-range transport (i.e., from China to the western U.S.) is important. Comparing the isotope ratios of the coals, the age of the deposits, and Pb isotope evolution models for the major geochemical reservoirs suggests that the lead isotope ratios (PbIC) in coals is strongly influenced by the depositional coal forming environment. 47 refs., 3 figs., 1 tab.

  7. Surface electrochemical control for fine coal and pyrite separation

    SciTech Connect

    Hu, Weibai; Huang, Qinping; Li, Jun; Zhu, Ximeng; Bodily, D.M.; Liang, Jun; Zhong, Tingke; Wadsworth, M.E.

    1991-01-01

    The ongoing work includes the characterization of coal pyrites, the floatability evaluation of three typical US coal samples, the flotation behavior of coal pyrites, the electrochemical measurement of the surface properties of coal pyrites, and the characterization of species produced at pyrite surfaces. This report contains three sections, Transpassive Oxidation of Pyrite,'' Flotation and Electrochemical Pretreatment,'' and Flotation Kinetics of Coal and Coal Pyrite.''

  8. Minor and trace elements in coal: a selected bibliography of reports in English, January 1976

    USGS Publications Warehouse

    U.S. Geological Survey

    1976-01-01

    A bibliography of 175 selected references on trace elements in is presented as a guide to readily available information and as an aid to further study. All the reports cited are in English, and most are applicable to the United States

  9. Catalytic conversion of alcohols. 28. Product selectivities for 2-methylcyclohexanol conversion with metal oxide catalysts

    SciTech Connect

    Dabbagh, H.A.; Hughes, C.G.; Davis, B.H. )

    1992-02-01

    Metal oxides exhibit a range of selectivities (dehydration percentage, alkene distribution and alcohol isomerization) for the conversion of a 2-methylcyclohexanol isomer. For many metal oxide catalysts, trans-2-methylcyclohexanol produces a predominance of the less stable 3-methylcyclohexene isomer. The grouping of metal oxides based on the production of the less stable alkene isomers from 2-octanol is similar to that for trans-2-methlycyclohexanol. It is proposed that the same catalytic properties determine the selectivity for both reactants: for smaller metal cations the product selectivity is determined by steric crowding in the transition state, and for the larger cations the product selectivity is determined by the basicity of the oxygen anion and the relative acidity of the {beta}-hydrogens that are eliminated to produce water.

  10. Mechanism of the selective catalytic oxidation of slip ammonia over Ru-modified Ce-Zr complexes determined by in situ diffuse reflectance infrared Fourier transform spectroscopy.

    PubMed

    Chen, Wanmiao; Ma, Yongpeng; Qu, Zan; Liu, Qinghang; Huang, Wenjun; Hu, Xiaofang; Yan, Naiqiang

    2014-10-21

    The slip ammonia from selective catalytic reduction (SCR) of NOx in coal-fired flue gas can result in deterioration of the utilities or even the environmental issues. To achieve selective catalytic oxidation (SCO) of slip ammonia, Ru-modified Ce-Zr solid solution catalysts were prepared and evaluated under various conditions. It was found that the Ru/Ce(0.6)Zr(0.4)O2(polyvinylpyrrolidone (PVP)) catalyst displayed significant catalytic activity and the slip ammonia was almost completely removed with the coexistence of NOx and SO2. Interestingly, the effect of SO2 on NH3 oxidation was bifacial, and the N2 selectivity of the resulting products was as high as 100% in the presence of SO2 and NH3. The mechanism of the SCO of NH3 over Ru/Ce(0.6)Zr(0.4)O2(PVP) was studied using various techniques, and the results showed that NH3 oxidation follows an internal SCR (iSCR) mechanism. The adsorbed ammonia was first activated and reacted with lattice oxygen atoms to form an -HNO intermediate. Then, the -HNO mainly reacted with atomic oxygen from O2 to form NO. Meanwhile, the formed NO interacted with -NH2 to N2 with N2O as the byproduct, but the presence of SO2 can effectively inhibit the production of N2O.

  11. Mechanism of the selective catalytic oxidation of slip ammonia over Ru-modified Ce-Zr complexes determined by in situ diffuse reflectance infrared Fourier transform spectroscopy.

    PubMed

    Chen, Wanmiao; Ma, Yongpeng; Qu, Zan; Liu, Qinghang; Huang, Wenjun; Hu, Xiaofang; Yan, Naiqiang

    2014-10-21

    The slip ammonia from selective catalytic reduction (SCR) of NOx in coal-fired flue gas can result in deterioration of the utilities or even the environmental issues. To achieve selective catalytic oxidation (SCO) of slip ammonia, Ru-modified Ce-Zr solid solution catalysts were prepared and evaluated under various conditions. It was found that the Ru/Ce(0.6)Zr(0.4)O2(polyvinylpyrrolidone (PVP)) catalyst displayed significant catalytic activity and the slip ammonia was almost completely removed with the coexistence of NOx and SO2. Interestingly, the effect of SO2 on NH3 oxidation was bifacial, and the N2 selectivity of the resulting products was as high as 100% in the presence of SO2 and NH3. The mechanism of the SCO of NH3 over Ru/Ce(0.6)Zr(0.4)O2(PVP) was studied using various techniques, and the results showed that NH3 oxidation follows an internal SCR (iSCR) mechanism. The adsorbed ammonia was first activated and reacted with lattice oxygen atoms to form an -HNO intermediate. Then, the -HNO mainly reacted with atomic oxygen from O2 to form NO. Meanwhile, the formed NO interacted with -NH2 to N2 with N2O as the byproduct, but the presence of SO2 can effectively inhibit the production of N2O. PMID:25229460

  12. In situ vibrational spectroscopic investigation of C{sub 4} hydrocarbon selective oxidation over vanadium-phosphorus-oxide catalysts

    SciTech Connect

    Xue, Z.Y.

    1999-05-10

    n-Butane selective oxidation over the VPO catalyst to maleic anhydride is the first and only commercialized process of light alkane selective oxidation. The mechanism of this reaction is still not well known despite over twenty years of extensive studies, which can partially be attributed to the extreme difficulties to characterize catalytic reactions real-time under typical reaction conditions. In situ spectroscopic characterization techniques such as Infrared spectroscopy and laser Raman spectroscopy were used in the current mechanistic investigations of n-butane oxidation over VPO catalysts. To identify the reaction intermediates, oxidation of n-butane, 1,3-butadiene and related oxygenates on the VPO catalyst were monitored using FTIR spectroscopy under transient conditions. n-Butane was found to adsorb on the VPO catalyst to form olefinic species, which were further oxidized to unsaturated, noncyclic carbonyl species. The open chain dicarbonyl species then experienced cycloaddition to form maleic anhydride. VPO catalyst phase transformations were investigated using in situ laser Raman spectroscopy. This report contains Chapter 1: General introduction; Chapter 2: Literature review; and Chapter 5: Conclusion and recommendations.

  13. Selective oxidation of methanol to hydrogen over gold catalysts promoted by alkaline-earth-metal and lanthanum oxides.

    PubMed

    Hereijgers, Bart P C; Weckhuysen, Bert M

    2009-01-01

    A series of alumina-supported gold catalysts was investigated for the CO-free production of hydrogen by partial oxidation of methanol. The addition of alkaline-earth metal oxide promoters resulted in a significant improvement of the catalytic performance. The methanol conversion was ca. 85 % with all studied catalyst materials, however, the selectivity for hydrogen increased from 15 % to 51 % when going from the unpromoted to a BaO-promoted catalyst. The formation of the undesired byproducts CO, methane, and dimethyl ether was considerably reduced as well. The observed trend in catalyst performance follows the trend in increasing basicity of the studied promoter elements, indicating a chemical effect of the promoter material. Superior catalytic performance, in terms of H(2) and CO selectivity, was obtained with a Au/La(2)O(3) catalyst. At 300 degrees C the hydrogen selectivity reached 80 % with only 2 % CO formation, and the catalyst displayed a stable performance over at least 24 h on-stream. Furthermore, the formation of CO was found to be independent of the oxygen concentration in the feed. The commercial lanthanum oxide used in this study had a low specific surface area, which led to the formation of relative large gold particles. Therefore, the catalytic activity could be enhanced by decreasing the gold particle size through deposition on lanthanum oxide supported on high-surface-area alumina.

  14. CO2 Hydrogenation over Oxide-Supported PtCo Catalysts: The Role of the Oxide Support in Determining the Product Selectivity.

    PubMed

    Kattel, Shyam; Yu, Weiting; Yang, Xiaofang; Yan, Binhang; Huang, Yanqiang; Wan, Weiming; Liu, Ping; Chen, Jingguang G

    2016-07-01

    By simply changing the oxide support, the selectivity of a metal-oxide catalysts can be tuned. For the CO2 hydrogenation over PtCo bimetallic catalysts supported on different reducible oxides (CeO2 , ZrO2 , and TiO2 ), replacing a TiO2 support by CeO2 or ZrO2 selectively strengthens the binding of C,O-bound and O-bound species at the PtCo-oxide interface, leading to a different product selectivity. These results reveal mechanistic insights into how the catalytic performance of metal-oxide catalysts can be fine-tuned.

  15. Optical turn-on sensor based on graphene oxide for selective detection of D-glucosamine.

    PubMed

    Cheng, Rumei; Liu, Yong; Ou, Shengju; Pan, Yaqiong; Zhang, Shu; Chen, Hao; Dai, Liming; Qu, Jia

    2012-07-01

    By incorporating the well-known fluorophore 8-aminoquinoline into graphene oxide, we have successfully prepared a turn-on fluorescent sensor capable of specific detection of D-glucosamine with a high selectivity and sensitivity. This methodology provides a new concept for the design and development of highly selective and sensitive turn-on optical sensors for selective detection of aminosaccharides and many other biomolecules. PMID:22655914

  16. Selective Oxidation Technology and its Applications Toward Electronic and Optoelectronic Devices

    SciTech Connect

    Spahn, Olga B.; Allerman, Andrew A.; Choquette, Kent D.; Vawter, Gregory A.; Klem, John F.; Sullivan, Charles T.; Sullivan, John P.; Ashby, Carol I.; Smith, Arlee V.; Raymond, Thomas D.; Alford, Willima J.

    1999-07-01

    Selective oxidation of AlGaAs compounds has facilitated dramatic improvements in the performance of near IR VCSELS. Under the auspices of this proposal we have: (1) expanded our understanding of both the strengths and the limitations of this technology; (2) explored its applicability to other Al bearing materials; (3) utilized this technology base to demonstrate a variety of new electronic and optoelectronic devices; and (4) established the reliability and manufacturability of oxidized devices such as VCSELS. Specifically, we have investigated conditions required to maximize control of the oxidation process as well as those required to facilitate inhibit etching of the resultant oxide. Concurrently, studies were performed to extend the technology to other Al-bearing compounds such as Al(Ga)AsSb, InAl(Ga)P and Al(Ga)N. Several new devices utilizing the selective oxidation technology of AlGaAs, as well as Al(Ga)AsSb were be considered. On a separate front, we also explored the possibility of using oxidized AlGaAs and InAl(Ga)P to form GaAs/AIGaAs FETs. Finally, reliability and manufacturability issues of the high performance VCSELS fabricated using selective oxidation technology, were addressed.

  17. Evaluation of transition metal oxide as carrier-selective contacts for silicon heterojunction solar cells

    SciTech Connect

    Ding, L.; Boccard, Matthieu; Holman, Zachary; Bertoni, M.

    2015-04-06

    "Reducing light absorption in the non-active solar cell layers, while enabling the extraction of the photogenerated minority carriers at quasi-Fermi levels are two key factors to improve current generation and voltage, and therefore efficiency of silicon heterojunction solar devices. To address these two critical aspects, transition metal oxide materials have been proposed as alternative to the n- and p-type amorphous silicon used as electron and hole selective contacts, respectively. Indeed, transition metal oxides such as molybdenum oxide, titanium oxide, nickel oxide or tungsten oxide combine a wide band gap typically over 3 eV with a band structure and theoretical band alignment with silicon that results in high transparency to the solar spectrum and in selectivity for the transport of only one carrier type. Improving carrier extraction or injection using transition metal oxide has been a topic of investigation in the field of organic solar cells and organic LEDs; from these pioneering works a lot of knowledge has been gained on materials properties, ways to control these during synthesis and deposition, and their impact on device performance. Recently, the transfer of some of this knowledge to silicon solar cells and the successful application of some metal oxide to contact heterojunction devices have gained much attention. In this contribution, we investigate the suitability of various transition metal oxide films (molybdenum oxide, titanium oxide, and tungsten oxide) deposited either by thermal evaporation or sputtering as transparent hole or electron selective transport layer for silicon solar cells. In addition to systematically characterize their optical and structural properties, we use photoemission spectroscopy to relate compound stoichiometry to band structure and characterize band alignment to silicon. The direct silicon/metal oxide interface is further analyzed by quasi-steady state photoconductance decay method to assess the quality of surface

  18. Selective Inhibition of the Oxidation of Ferrous Iron or Sulfur in Thiobacillus ferrooxidans

    PubMed Central

    Harahuc, Lesia; Lizama, Hector M.; Suzuki, Isamu

    2000-01-01

    The oxidation of either ferrous iron or sulfur by Thiobacillus ferrooxidans was selectively inhibited or controlled by various anions, inhibitors, and osmotic pressure. Iron oxidation was more sensitive than sulfur oxidation to inhibition by chloride, phosphate, and nitrate at low concentrations (below 0.1 M) and also to inhibition by azide and cyanide. Sulfur oxidation was more sensitive than iron oxidation to the inhibitory effect of high osmotic pressure. These differences were evident not only between iron oxidation by iron-grown cells and sulfur oxidation by sulfur-grown cells but also between the iron and sulfur oxidation activities of the same iron-grown cells. Growth experiments with ferrous iron or sulfur as an oxidizable substrate confirmed the higher sensitivity of iron oxidation to inhibition by phosphate, chloride, azide, and cyanide. Sulfur oxidation was actually stimulated by 50 mM phosphate or chloride. Leaching of Fe and Zn from pyrite (FeS2) and sphalerite (ZnS) by T. ferrooxidans was differentially affected by phosphate and chloride, which inhibited the solubilization of Fe without significantly affecting the solubilization of Zn. PMID:10698768

  19. Effect of various coal contaminants on the performance of solid oxide fuel cells: Part I. Accelerated testing

    NASA Astrophysics Data System (ADS)

    Bao, JianEr; Krishnan, Gopala N.; Jayaweera, Palitha; Perez-Mariano, Jordi; Sanjurjo, Angel

    The contaminants that are potentially present in the coal-derived gas stream and their thermochemical nature are discussed. Accelerated testing was carried out on Ni-YSZ/YSZ/LSM solid oxide fuel cells (YSZ: yttria stabilized zirconia and LSM: lanthanum strontium manganese oxide) for eight main kind of contaminants: CH 3Cl, HCl, As, P, Zn, Hg, Cd and Sb at the temperature range of 750-850 °C. The As and P species, at 10 and 35 ppm, respectively, resulted in severe power density degradation at temperatures 800 °C and below. SEM and EDX analysis indicated that As attacked the Ni region of the anode surface and the Ni current collector, caused the break of the current collector and the eventual cell failure at 800 °C. The phosphorous containing species were found in the bulk of the anode, they were segregated and formed "grain boundary" like phases separating large Ni patches. These species are presumably nickel phosphide/phosphate and zirconia phosphate, which could break the Ni network for electron transport and inhibit the YSZ network for oxygen ion transport. The presence of 40 ppm CH 3Cl and 5 ppm Cd only affected the cell power density at above 800 °C and Cd caused significant performance loss. Whereas the presence of 9 ppm Zn, 7 ppm Hg and 8 ppm Sb only degraded the cell power density by less than 1% during the 100 h test in the temperature range of 750-850 °C.

  20. DEVELOPMENT OF IMPROVED CATALYSTS FOR THE SELECTIVE CATALYTIC REDUCTION OF NITROGEN OXIDES WITH HYDROCARBONS

    SciTech Connect

    Dr. Ates Akyurlu; Dr. Jale F. Akyurtlu

    2003-01-28

    Significant work has been done by the investigators on the cerium oxide-copper oxide based sorbent/catalysts for the combined removal of sulfur and nitrogen oxides from the flue gases of stationary sources. A relatively wide temperature window was established for the use of alumina-supported cerium oxide-copper oxide mixtures as regenerable sorbents for SO{sub 2} removal. Evaluation of these sorbents as catalysts for the selective reduction of NO{sub x} gave promising results with methane. Since the replacement of ammonia by methane is commercially very attractive, in this project, it was planned to investigate the effect of promoters on the activity and selectivity of copper oxide/cerium oxide-based catalysts and to obtain data on the reaction mechanism for the SCR with methane. The investigation of the reaction mechanism will help in the selection of promoters to improve the catalytic activity and selectivity of the sorbents in the SCR with methane. This will result in new catalyst formulations. The last component of the project involves our industrial partner TDA Research, and the objective is to evaluate long- term stability and durability of the prepared sorbent/catalysts. In the second year of the project, the catalysts were investigated for their SCR activity with methane in a microreactor setup and also, by the temperature-programmed desorption (TPD) technique. The results from the SCR experiments indicated that manganese is a more effective promoter than rhodium on the supported copper oxide-ceria catalysts under study; the effectiveness of the promoter increases with the increase in Ce/Cu ratio. The TPD profiles of the unpromoted catalyst (Cu/Ce=3) is different than those promoted with 0.1% rhodium. In the current reporting period, the screening of the promoted catalysts were completed, sufficient amount of the selected catalysts were prepared and delivered to TDA for long term deactivation testing.

  1. EVALUATION OF THE IMPACT OF CHLORINE ON MERCURY OXIDATION IN A PILOT-SCALE COAL COMBUSTION--THE EFFECT OF COAL BLENDING

    EPA Science Inventory

    Coal-fired power plants are a major source of mercury (Hg) released into the environment and the utility industry is currently investigating options to reduce Hg emissions. The EPA Clean Air Mercury Rule (CAMR) depends heavily on the co-benefit of mercury removal by existing and ...

  2. Coal recovery process

    DOEpatents

    Good, Robert J.; Badgujar, Mohan

    1992-01-01

    A method for the beneficiation of coal by selective agglomeration and the beneficiated coal product thereof is disclosed wherein coal, comprising impurities, is comminuted to a particle size sufficient to allow impurities contained therein to disperse in water, an aqueous slurry is formed with the comminuted coal particles, treated with a compound, such as a polysaccharide and/or disaccharide, to increase the relative hydrophilicity of hydrophilic components, and thereafter the slurry is treated with sufficient liquid agglomerant to form a coagulum comprising reduced impurity coal.

  3. (Bioprocessing of lignite coals using reductive microorganisms)

    SciTech Connect

    Crawford, D.L.

    1990-01-01

    The objectives of this report are to: (1) characterize selected aerobic bacterial strains for their abilities to depolymerize lignite coal polymers, and isolate and identify the extracellular enzymes responsible for depolymerization of the coal; (2) characterize selected strictly anaerobic bacteria, that were previously shown to reductively transform coal substructure model compounds, for the ability to similarly transform polymeric coal; and (3) isolate more strains of anaerobic bacteria by enrichment using additional coal substructure model compounds and coal as substrates.

  4. Cooperative research program in coal liquefaction

    SciTech Connect

    Huffman, G.P.; Sendlein, L.V.A.

    1990-01-01

    Cooperative research in coal liquefaction is presented. Topics include: Sulfate-promoted metal oxides as direct coal liquefaction catalysts; low temperature depolymerization and liquefaction of premium US coal samples; construction of continuous flow-through gas reactor for liquefaction investigations; examination of ferric sulfide as a liquefaction catalyst; generic structural characterization and liquefaction research; spectroscopic studies of coal macerals depolymerization catalyzed by iron chloride; characterization of catalysts used in coal hydrogenation systems; coal structure/liquefaction yield correlation by means of advanced NMR techniques; mass spectrometry of coal derived liquids: determination of molecular weight distributions; catalyst cracking, hydrogenation and liquefaction of coals under milder conditions; ENDOR investigations of coal liquefaction under mild conditions; direct determination of hydroaromatic structures in coal and coal conversion products by catalytic dehydrogenation; surface characterization of APCSB coals by XPS; computation chemistry of model compounds and molecular fragments of relevance to coal liquefaction; chemical characterization and hydrogenation reactions of single coal particles; the role of hydrogen during liquefaction using donor and non-donor solvents; solvent sorption and FTIR studies on the effect of catalytic depolymerization reactions in coal; bioprocessing of coal; chemical routes to breaking bonds: new approaches to low-temperature liquefaction; an investigation into the reactivity of isotetralin and tetralin using molecular orbital calculations; coal liquefaction modification for enhanced reactivity; catalytic hydropyrolysis and energized extraction of coals; gallium catalyst in mild coal liquefaction -- potential of temperature microscope in coal liquefaction; evaluation of nitride catalysts for hydrotreatment and coal liquefaction; and improved catalysts for coal liquefaction and coprocessing.

  5. Oxidation of elemental mercury by modified spent TiO2-based SCR-DeNOx catalysts in simulated coal-fired flue gas.

    PubMed

    Zhao, Lingkui; Li, Caiting; Zhang, Xunan; Zeng, Guangming; Zhang, Jie; Xie, Yin'e

    2016-01-01

    In order to reduce the costs, the recycle of spent TiO2-based SCR-DeNOx catalysts were employed as a potential catalytic support material for elemental mercury (Hg(0)) oxidation in simulated coal-fired flue gas. The catalytic mechanism for simultaneous removal of Hg(0) and NO was also investigated. The catalysts were characterized by Brunauer-Emmett-Teller (BET), scanning electron microscope (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) method. Results indicated that spent TiO2-based SCR-DeNOx catalyst supported Ce-Mn mixed oxides catalyst (CeMn/SCR1) was highly active for Hg(0) oxidation at low temperatures. The Ce1.00Mn/SCR1 performed the best catalytic activities, and approximately 92.80% mercury oxidation efficiency was obtained at 150 °C. The inhibition effect of NH3 on Hg(0) oxidation was confirmed in that NH3 consumed the surface oxygen. Moreover, H2O inhibited Hg(0) oxidation while SO2 had a promotional effect with the aid of O2. The XPS results illustrated that the surface oxygen was responsible for Hg(0) oxidation and NO conversion. Besides, the Hg(0) oxidation and NO conversion were thought to be aided by synergistic effect between the manganese and cerium oxides. PMID:26370819

  6. Oxidation of elemental mercury by modified spent TiO2-based SCR-DeNOx catalysts in simulated coal-fired flue gas.

    PubMed

    Zhao, Lingkui; Li, Caiting; Zhang, Xunan; Zeng, Guangming; Zhang, Jie; Xie, Yin'e

    2016-01-01

    In order to reduce the costs, the recycle of spent TiO2-based SCR-DeNOx catalysts were employed as a potential catalytic support material for elemental mercury (Hg(0)) oxidation in simulated coal-fired flue gas. The catalytic mechanism for simultaneous removal of Hg(0) and NO was also investigated. The catalysts were characterized by Brunauer-Emmett-Teller (BET), scanning electron microscope (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) method. Results indicated that spent TiO2-based SCR-DeNOx catalyst supported Ce-Mn mixed oxides catalyst (CeMn/SCR1) was highly active for Hg(0) oxidation at low temperatures. The Ce1.00Mn/SCR1 performed the best catalytic activities, and approximately 92.80% mercury oxidation efficiency was obtained at 150 °C. The inhibition effect of NH3 on Hg(0) oxidation was confirmed in that NH3 consumed the surface oxygen. Moreover, H2O inhibited Hg(0) oxidation while SO2 had a promotional effect with the aid of O2. The XPS results illustrated that the surface oxygen was responsible for Hg(0) oxidation and NO conversion. Besides, the Hg(0) oxidation and NO conversion were thought to be aided by synergistic effect between the manganese and cerium oxides.

  7. The release of iron during coal combustion. Milestone report

    SciTech Connect

    Baxter, L.L.

    1995-06-01

    Iron plays an important role in the formation of both fly ash and deposits in many pulverized-coal-fired boilers. Several authors indicate that iron content is a significant indicator of the slagging propensity of a majority of US bituminous coals, in particular eastern bituminous coals. The pyritic iron content of these coals is shown to be a particularly relevant consideration. A series of investigations of iron release during combustion is reported for a suite of coals ranging in rank from lignite to low-volatile bituminous coal under combustion conditions ranging from oxidizing to inert. Experimental measurements are described in which, under selected conditions, major fractions of the iron in the coal are released within a 25 ms period immediately following coal devolatilization. Mechanistic interpretation of the data suggest that the iron is released as a consequence of oxygen attack on porous pyrrhotite particles. Experimental testing of the proposed mechanism reveals that the release is dependent on the presence of both pyrite in the raw coal and oxygen in the gas phase, that slow preoxidation (weathering) of the pyrite significantly inhibits the iron release, and that iron loss increases as oxygen penetration of the particle increases. Each observation is consistent with the postulated mechanism.

  8. Selective Autooxidation of Ethanol over Titania-Supported Molybdenum Oxide Catalysts: Structure and Reactivity

    PubMed Central

    Caro, Carlos; Thirunavukkarasu, K; Anilkumar, M; Shiju, N R; Rothenberg, Gadi

    2012-01-01

    We study the selective catalytic oxidation of ethanol with air as a sustainable alternative route to acetaldehyde. The reaction is catalysed by molybdenum oxide supported on titania, in a flow reactor under ambient pressure. High selectivity to acetaldehyde (70%–89%, depending on the Mo loading) is obtained at 150 °C. Subsequently, we investigate the structure/performance relationship for various molybdenum oxide species using a combination of techniques including diffuse reflectance UV-visible, infrared, X-ray photoelectron spectroscopies, X-ray diffraction and temperature programmed reduction. As their surface density increases, the monomeric molybdenum oxide species undergo two-dimensional and three-dimensional oligomerisation. This results in polymolybdates and molybdenum oxide crystallites. Importantly, the ethanol oxidation rate depends not only on the overall molybdenum loading and dispersion, but also on the type of molybdenum oxide species prevalent at each surface density and on the domain size. As the molybdenum oxide oligomerisation increases, electron delocalisation becomes easier. This lowers the absorption edge energy and increases the reaction rate. PMID:23396482

  9. Fe-MCM-41 from Coal-Series Kaolin as Catalysts for the Selective Catalytic Reduction of NO with Ammonia

    NASA Astrophysics Data System (ADS)

    Li, Shuiping; Wu, Qisheng; Lu, Guosen; Zhang, Changsen; Liu, Xueran; Cui, Chong; Yan, Zhiye

    2013-12-01

    Fe-MCM-41, one kind of high-ordered mesoporous materials catalysts, with molar ratio of Fe/Si = 0.01-0.1, was synthesized by hydrothermal method from coal-series kaolin. Fe-MCM-41 catalysts were characterized by Fourier transform infrared spectroscopy, high resolution transmission electron microscopy, N2 adsorption-desorption, x-ray photoelectron spectroscopy, and UV-vis spectroscopy. The results clearly indicated that: (1) all the samples exhibited typical hexagonal arrangement of mesoporous structure; (2) the incorporation of tiny amount of Fe3+ onto the surface and pore channel of MCM-41 mesoporous materials could efficiently promote the deNO x activity of these catalysts. Moreover, the Fe-MCM-41 mesoporous materials were evaluated in the selective catalytic reduction of NO with NH3. The results showed that Fe-MCM-41 catalyst with Fe/Si = 0.05 showed the highest catalytic activity at 350 °C, a gas hourly space velocity of 5000 h-1, n(NH3)/ n(NO) = 1.1, and O2% = 2.5%.

  10. Method of extracting coal from a coal refuse pile

    DOEpatents

    Yavorsky, Paul M.

    1991-01-01

    A method of extracting coal from a coal refuse pile comprises soaking the coal refuse pile with an aqueous alkali solution and distributing an oxygen-containing gas throughout the coal refuse pile for a time period sufficient to effect oxidation of coal contained in the coal refuse pile. The method further comprises leaching the coal refuse pile with an aqueous alkali solution to solubilize and extract the oxidized coal as alkali salts of humic acids and collecting the resulting solution containing the alkali salts of humic acids. Calcium hydroxide may be added to the solution of alkali salts of humic acid to form precipitated humates useable as a low-ash, low-sulfur solid fuel.

  11. Rare-Earth Oxide (Yb2O3) Selective Emitter Fabrication and Evaluation

    NASA Technical Reports Server (NTRS)

    Jennette, Bryan; Gregory, Don A.; Herren, Kenneth; Tucker, Dennis; Smith, W. Scott (Technical Monitor)

    2001-01-01

    This investigation involved the fabrication and evaluation of rare-earth oxide selective emitters. The first goal of this study was to successfully fabricate the selective emitter samples using paper and ceramic materials processing techniques. The resulting microstructure was also analyzed using a Scanning Electron Microscope. All selective emitter samples fabricated for this study were made with ytterbium oxide (Yb2O3). The second goal of this study involved the measurement of the spectral emission and the radiated power of all the selective emitter samples. The final goal of this study involved the direct comparison of the radiated power emitted by the selective emitter samples to that of a standard blackbody at the same temperature and within the same wavelength range.

  12. Thermal NF3 fluorination/oxidation of cobalt, yttrium, zirconium, and selected lanthanide oxides

    SciTech Connect

    Scheele, Randall D.; McNamara, Bruce K.; Casella, Andrew M.; Kozelisky, Anne E.; Neiner, Doinita

    2013-02-01

    This paper presents results of our continuing investigation on the use of nitrogen trifluoride as a fluorination or fluorination/oxidation agent for separating valuable constituents from used nuclear fuels by exploiting the different volatilities of the constituent fission product and actinide fluorides. This article focuses on fission products that do not have volatile fluorides or oxyfluorides at expected operations temperatures. Our thermodynamic calculations show that nitrogen trifluoride has the potential to completely fluorinate fission product oxides to their fluorides. Simultaneous thermogravimetric and differential thermal analyses show that the oxides of cobalt, zirconium, and the lanthanides are fluorinated but do not form volatile fluorides when treated with nitrogen trifluoride at temperatures up to 550°C. Our studies of gadolinium-doped commercial nuclear fuel indicate that nitrogen trifluoride can extract uranium from the non-volatile gadolinium.

  13. Selective Aerobic Oxidation of 5-(Hydroxymethyl)furfural to 5-Formyl-2-furancarboxylic Acid in Water.

    PubMed

    Ventura, Maria; Aresta, Michele; Dibenedetto, Angela

    2016-05-23

    A simple, cheap, and selective catalyst based on copper/cerium oxides is described for the oxidation of 5-(hydroxymethyl)furfural (5-HMF) in water. An almost quantitative conversion (99 %) with excellent (90 %) selectivity towards the formation of 5-formyl-2-furancarboxylic acid, a platform molecule for other high value chemicals, is observed. The catalyst does not require any pretreatment or additives, such as bases, to obtain high yield and selectivity in water as solvent and using oxygen as oxidant. When a physical mixture of the oxides is used, low conversion and selectivity are observed. Air can be used instead of oxygen, but a lower conversion rate is observed if the same overall pressure is used, and the selectivity remains high. The catalyst can be recovered almost quantitatively and reused. Deactivation of the catalyst, observed in repeated runs, is due to the deposition of humins on its surface. Upon calcination the catalyst almost completely recovers its activity and selectivity, proving that the catalyst is robust. PMID:27101568

  14. Decision criteria for the selection of wet oxidation and conventional biological treatment.

    PubMed

    Collado, Sergio; Laca, Adriana; Diaz, Mario

    2012-07-15

    The suitability of wet oxidation or biological treatments for the degradation of industrial wastewaters is here discussed. Advantages of these operations, either singly or in combination, are discussed on the basis of previous experimental results from laboratory and industry. Decision diagrams for the selection of conventional biological treatment, wet oxidation or a combination of both techniques are suggested according to the type of pollutant, its concentration and the wastewater flow rate.

  15. Niobium phosphates as new highly selective catalysts for the oxidative dehydrogenation of ethane.

    PubMed

    Weng, Weihao; Davies, Mathew; Whiting, Gareth; Solsona, Benjamin; Kiely, Christopher J; Carley, Albert F; Taylor, Stuart H

    2011-10-14

    Several niobium phosphate phases have been prepared, fully characterized and tested as catalysts for the selective oxidation of ethane to ethylene. Three distinct niobium phosphate catalysts were prepared, and each was comprised predominantly of a different bulk phase, namely Nb(2)P(4)O(15), NbOPO(4) and Nb(1.91)P(2.82)O(12). All of the niobium phosphate catalysts showed high selectivity towards ethylene, but the best catalyst was Nb(1.91)P(2.82)O(12), which was produced from the reduction of niobium oxide phosphate (NbOPO(4)) by hydrogen. It was particularly selective for ethylene, giving ca. 95% selectivity at 5% conversion, decreasing to ca. 90% at 15% conversion, and only produced low levels of carbon oxides. It was also determined that the only primary product from ethane oxidation over this catalyst was ethylene. Catalyst activity also increased with time-on-line, and this behaviour was ascribed to an increase of the concentration of the Nb(1.91)P(2.82)O(12) phase, as partially transformed NbOPO(4), formed during preparation, was converted to Nb(1.91)P(2.82)O(12) during use. Catalysts with predominant phases of Nb(2)P(4)O(15) and NbOPO(4) also showed appreciable activity and selectivities to ethylene with values around 75% and 85% respectively at 5% ethane conversion. The presence of phosphorous is required to achieve high ethylene selectivity, as orthorhombic and monoclinic Nb(2)O(5) catalysts showed similar activity, but displayed selectivities to ethylene that were <20% under the same reaction conditions. To the best of our knowledge, this is the first time that niobium phosphates have been shown to be highly selective catalysts for the oxidation of ethane to ethylene, and demonstrates that they are worthy candidates for further study. PMID:21881631

  16. State coal profiles, January 1994

    SciTech Connect

    Not Available

    1994-02-02

    The purpose of State Coal Profiles is to provide basic information about the deposits, production, and use of coal in each of the 27 States with coal production in 1992. Although considerable information on coal has been published on a national level, there is a lack of a uniform overview for the individual States. This report is intended to help fill that gap and also to serve as a framework for more detailed studies. While focusing on coal output, State Coal Profiles shows that the coal-producing States are major users of coal, together accounting for about three-fourths of total US coal consumption in 1992. Each coal-producing State is profiled with a description of its coal deposits and a discussion of the development of its coal industry. Estimates of coal reserves in 1992 are categorized by mining method and sulfur content. Trends, patterns, and other information concerning production, number of mines, miners, productivity, mine price of coal, disposition, and consumption of coal are detailed in statistical tables for selected years from 1980 through 1992. In addition, coal`s contribution to the State`s estimated total energy consumption is given for 1991, the latest year for which data are available. A US summary of all data is provided for comparing individual States with the Nation as a whole. Sources of information are given at the end of the tables.

  17. Oxidizer Selection for the ISTAR Program (Liquid Oxygen versus Hydrogen Peroxide)

    NASA Technical Reports Server (NTRS)

    Quinn, Jason Eugene; Koelbl, Mary E. (Technical Monitor)

    2002-01-01

    This paper discusses a study of two alternate oxidizers, liquid oxygen and hydrogen peroxide, for use in a rocket based combined cycle (RBCC) demonstrator vehicle. The flight vehicle is baselined as an airlaunched self-powered Mach 0.7 to 7 demonstration of an RBCC engine through all or its air breathing propulsion modes. Selection of an alternate oxidizer has the potential to lower overall vehicle size, system complexity/ cost and ultimately the total program risk. This trade study examined the oxidizer selection effects upon the overall vehicle performance, safety and operations. After consideration of all the technical and programmatic details available at this time, 90% hydrogen peroxide was selected over liquid oxygen for use in this program.

  18. Activity and selectivity control by niobium for the preferential oxidation of co on pt supported catalysts

    SciTech Connect

    Guerrero, S.; Miller, J.T.; Wolf, E.E.

    2010-10-22

    The promotional effect of Nb on Pt supported on alumina or on niobia, was studied for the preferential oxidation of CO (PROX) in hydrogen. The results show a unique effect of Nb as a promoter to Pt. At low Nb loadings on Pt/alumina, the CO oxidation activity and selectivity are significantly increased. The CO selectivity is 100% at conversions up to about 60%. For Pt supported on Nb{sub 2}O{sub 5}, however, the CO oxidation activity is strongly suppressed with low CO conversion but high H{sub 2} oxidation activity. Pt on niobia, therefore, is poorly selective for the PROX reaction, but is an active hydrogen oxidation catalyst, resistant to CO poisoning. For Pt supported on highly loaded Nb-alumina or Nb{sub 2}O{sub 5}, XPS indicate an increase in the Pt and Nb oxidation states. These surface changes also correlate with changes in the DRIFTS spectra suggesting that CO is more weakly adsorbed on Pt/Nb{sub 2}O{sub 5} compared to Pt/Al{sub 2}O{sub 3}, or Pt/Nb-Al{sub 2}O{sub 3}.

  19. Iron-tellurium-selenium mixed oxide catalysts for the selective oxidation of propylene to acrolein

    SciTech Connect

    Patel, B.M.; Price, G.L. )

    1990-05-01

    This paper reports on iron-tellurium-selenium mixed oxide catalysts prepared by coprecipitation from aqueous solution investigated for the propylene to acrolein reaction in the temperature range 543-773 K. Infrared spectroscopy, electron dispersive X-ray analysis, X-ray diffraction, and isotopic tracer techniques have also been employed to characterize this catalytic system. Properties of the Fe-Te-Se mixed oxide catalysts have been compared with Fe-Te mixed oxides in an effort to deduce the functionality of Se. The selenium in the Fe-Te-Se-O catalyst has been found to be the hydrocarbon activating site. The activation energies for the acrolein and carbon dioxide formation are 71 and 54 kJ/mol, respectively. Reactions carried out with {sup 18}O{sub 2} have shown lattice oxygen to be primarily responsible for the formation of both acrolein and carbon dioxide. The initial and rate-determining step for acrolein formation is hydrogen abstraction as determined by an isotope effect associated with the C{sub 3}D{sub 6} reaction. No isotope effect is observed for carbon dioxide formation from C{sub 3}D{sub 6} suggesting that CO{sub 2} is formed by parallel, not consecutive, oxidation of propylene.

  20. Selective aerobic alcohol oxidation method for conversion of lignin into simple aromatic compounds

    DOEpatents

    Stahl, Shannon S; Rahimi, Alireza

    2015-03-03

    Described is a method to oxidize lignin or lignin sub-units. The method includes oxidation of secondary benzylic alcohol in the lignin or lignin sub-unit to a corresponding ketone in the presence of unprotected primarily aliphatic alcohol in the lignin or lignin sub-unit. The optimal catalyst system consists of HNO.sub.3 in combination with another Bronsted acid, in the absence of a metal-containing catalyst, thereby yielding a selectively oxidized lignin or lignin sub-unit. The method may be carried out in the presence or absence of additional reagents including TEMPO and TEMPO derivatives.