Science.gov

Sample records for lignite ash slags

  1. Predicting slag viscosity from coal ash composition

    SciTech Connect

    Laumb, J.; Benson, S.A.; Katrinak, K.A.; Schwalbe, R.; McCollor, D.P.

    1999-07-01

    Management of slag flow from cyclone-fired utility boilers requires accurate prediction of viscosity. Cyclones tend to build up slag when the cyclone combustion temperature is less than the temperature required to melt and tap the ash from the coal being fired. Cyclone-fired boilers designed for lignite are equipped with predry systems, which remove 6-9% of the moisture from the coal. Cyclones tend to slag when the as-received heating value of the fuel is less than 6350 Btu/lb and T250 (temperature where viscosity equals 250 poise) is greater than 2350 F. The T250 value, as well as the rest of the viscosity-temperature relationship, can be predicted using models based on coal ash composition. The focus of this work is to evaluate several models in terms of their agreement with measured viscosities. Viscosity measurements were made for ten samples, including nine lignite coals and one lignite-derived slag. Model performance is related to the SiO{sub 2}, CaO, and Fe{sub 2}O{sub 3} contents of the slag. The Sage and McIlroy and Kalmanovitch models worked best for high SiO{sub 2} and low Fe{sub 2}O{sub 3} fuels. The Senior model worked best when Fe{sub 2}O{sub 3} content was moderate to high.

  2. Utilization of lignite ash in concrete mixture

    SciTech Connect

    Demirbas, A.; Karslioglu, S.; Ayas, A.

    1995-12-01

    In this article 11 ashes from various Turkish lignite sources were studied to show the effects upon lignite ash quality for use as a mineral admixture in concrete. The lignite ashes were classified into two general types (Class A and Class B) based on total of silica, alumina, and iron oxide. Total content of the three major oxides must be more than 50% for Class A lignite ash and more than 70% for Class B lignite ash. When 25% of the cement was replaced by LA-1 (Class A) lignite ash, based on 300 kg/m{sup 3} cementitious material, the 28-day compressive strength increased 24.3% compared to the control mix. The optimal lignite ash replacement was 25% at 300 kg/m{sup 3} cementitious material.

  3. Natural radioactivity in lignites and lignite ash: Final report

    SciTech Connect

    Greiner, N.R.; Wagner, P.

    1987-04-01

    Natural radioactivity in a Texas lignite field and in leachates from lignite ash from power plants was measured. The radioactivity concentrations found (4 ppM uranium in the lignite, 16 ppM uranium in the lignite ash, and a few picocuries of natural radionuclides per liter in the leachates) do not differ appreciably from those found previously in similar samples and in natural materials such as soils and ground waters. Additional information on stable elements are reported for both the lignites and the leachates.

  4. Radiological investigation of lignite ash. The case of the West Macedonia Lignite Center (Greece)

    SciTech Connect

    Tsikritzis, L.I.; Fotakis, M.; Tzimkas, N.; Tsikritzi, R.; Trikoilidou, E.; Kolovos, N.

    2009-07-01

    This article investigates the natural radioactivity of 26 ash samples, laboratory produced from lignite samples collected in the West Macedonia Lignite Center in Northern Greece. The activity concentrations of {sup 40}K, {sup 235}U, {sup 238}U, {sup 226}Ra, {sup 228}Ra, and 232Th were measured by spectroscopy and found four to five times higher than those in the original lignite samples. The radionuclides transfer factors depend on the characteristics of the combustion process and were found higher for {sup 232}Th, {sup 228}Ra, and 40K, because of their closer affinity with the inorganic fraction of the lignite. Compared with other results found in the published literature, the studied ash has relatively high content in radioactivity, but the resulting radiation dose from the radionuclide emissions in the West Macedonia Lignite Center do not contribute significantly to the total effective dose.

  5. Synthesis of inorganic polymers using fly ash and primary lead slag.

    PubMed

    Onisei, S; Pontikes, Y; Van Gerven, T; Angelopoulos, G N; Velea, T; Predica, V; Moldovan, P

    2012-02-29

    The present work reports on the synthesis and properties of inorganic polymers ("geopolymers") made of 100% fly ash from lignite's combustion, 100% primary lead slag and mixtures of the two. In the inorganic polymers with both fly ash and lead slag the main crystalline phases detected are wüstite, magnetite, sodium zinc silicate, quartz, anorthite, and gehlenite; litharge partially dissolves. FTIR analysis in these samples revealed that the main peaks and bands of end members also exist, along with a new amorphous reaction product. In terms of microstructure, both fly ash and lead slag dissolve and contribute in the binding phase whereas the larger particles act as aggregates. For an increasing lead slag in the composition, the binding phase is changing in chemistry and reaches PbO values higher than 50 wt.% for the 100% lead slag inorganic polymer. Regarding the properties of fly ash and lead slag inorganic polymers, compressive strength is higher than 35 MPa in all cases and water absorption diminishes as the lead slag content increases. A comparison of leaching results before and after polymerisation reveals that pH is an important factor as Pb is immobilised in the binding phase, unlike Zn and As. PMID:22252096

  6. Preventing ash agglomeration during gasification of high-sodium lignite

    SciTech Connect

    Robert S. Dahlin; Johnny R. Dorminey; WanWang Peng; Roxann F. Leonard; Pannalal Vimalchand

    2009-01-15

    Various additives were evaluated to assess their ability to prevent ash agglomeration during the gasification of high-sodium lignite. Additives that showed promise in simple muffle furnace tests included meta-kaolin, vermiculite, two types of silica fume, and one type of bauxite. Additives that were tested and rejected included dolomite, calcite, sand flour, kaolinite, fine kaolin, and calcined bauxite. Based on the muffle furnace test results, the meta-kaolin was selected for a follow-on demonstration in a pilot-scale coal gasifier. Pilot-scale testing showed that the addition of coarse (minus 14-mesh, 920-{mu}m mean size) meta-kaolin at a feed rate roughly equivalent to the ash content of the lignite (10 wt %) successfully prevented agglomeration and deposition problems during gasification of high-sodium lignite at a maximum operating temperature of 927{sup o}C (1700{sup o}F). 13 refs., 24 figs., 1 tab.

  7. Radiative properties of ash and slag

    SciTech Connect

    Solomon, P.R.; Markham, J.R.

    1989-01-01

    Thermal radiation plays a key role in the operation and efficiency of combustion systems, accounting for over 90% of the heat transfer. The analysis of radiative heat transfer in coal-fired boilers, combustion chambers and other energy systems requires accounting for the effects of inorganic deposits on bounding surfaces and of entrained particulates, such as pulverized coal, char and fly-ash. These effects can be predicted; however, the accuracy in predicting the radiative properties of entrained particles (ash) and deposit layers (slag) is limited by inaccurate knowledge of the physical/chemical properties of the materials over a range of material temperatures and radiative wavelengths that is representative of conditions in practical combustion systems. The objective of this project is to make laboratory measurements of the radiative properties of extracted ash deposit samples. During this quarter, technique validation measurements were performed on several test samples. Technique validation has been achieved for infrared opaque and semi-transparent materials that exhibit a high degree of specular reflection (i.e. having a negligible diffuse reflectance component). Validation has not been achieved for non-specular reflecting surfaces, but work is progressing on modifying the present system to accommodate these materials.

  8. Lignite air-steam gasification in the fluidized bed of iron-containing slag catalysts

    SciTech Connect

    Kuznetsov, B.N.; Shchipko, M.L.; Golovin, Yu.

    1995-12-01

    The influence of fluidized bed of iron-containing slag particles on air-steam gasification of powdered Kansk-Achinsk lignite in entrained flow was studied in pilot installation with productivity about 60 kg per hour. Slag of Martin process and boiler slag were used as catalytic active materials until their complete mechanical attrition. Two following methods of catalytic gasification of lignite were compared: the partial gasification in stationary fluidized bed of slag particles with degree of fuel conversion 40-70% and complete gasification in circulating bed of slag particles. In the first case only the most reactive part of fuel is gasified with the simultaneously formation of porous carbon residue with good sorption ability. It was found the catalytic fluidized bed improves heat transfer from combustion to reduction zone of gas-generator and increases the rate of fuel conversion at the temperature range 900-1000{degrees}C. At these temperatures the degree of conversion is depended considerably on the duration time of fuel particles in the catalytic fluidized bed. The influence of catalytic fluidized bed height and velocity of reaction mixture on the temperature profiles in the gas-generator was studied. The optimal relationship was found between the fluidized bed height and velocity of flow which makes possible to produce the gas with higher calorific value at maximum degree of fuel conversion.

  9. Enhancing performance and durability of slag made from incinerator bottom ash and fly ash.

    PubMed

    Chiou, Ing-Jia; Wang, Kuen-Sheng; Tsai, Chen-Chiu

    2009-02-01

    This work presents a method capable of melting the incinerator bottom ash and fly ash in a plasma furnace. The performance of slag and the strategies for recycling of bottom ash and fly ash are improved by adjusting chemical components of bottom ash and fly ash. Ashes are separated by a magnetic process to improve the performance of slag. Analytical results indicate that the air-cooled slag (ACS) and magnetic-separated slag (MSS) have hardness levels below 590 MPa, indicating fragility. Additionally, the hardness of crystallized slag (RTS) is between 655 and 686 MPa, indicating toughness. The leached concentrations of heavy metals for these three slags are all below the regulatory limits. ACS appears to have better chemical stability than MSS, and is not significantly different from RTS. In the potential alkali-silica reactivity of slag, MSS falls on the border between the harmless zone and the potentially harmful zone. ACS and RTS fall in the harmless zone. Hence, the magnetic separation procedure of ashes does not significantly improve the quality of slag. However, RTS appears to improve its quality. PMID:18544471

  10. Workability and strength of lignite bottom ash geopolymer mortar.

    PubMed

    Sathonsaowaphak, Apha; Chindaprasirt, Prinya; Pimraksa, Kedsarin

    2009-08-30

    In this paper, the waste lignite bottom ash from power station was used as a source material for making geopolymer. Sodium silicate and sodium hydroxide (NaOH) were used as liquid for the mixture and heat curing was used to activate the geopolymerization. The fineness of bottom ash, the liquid alkaline/ash ratio, the sodium silicate/NaOH ratio and the NaOH concentration were studied. The effects of the additions of water, NaOH and napthalene-based superplasticizer on the workability and strength of the geopolymer mortar were also studied. Relatively high strength geopolymer mortars of 24.0-58.0 MPa were obtained with the use of ground bottom ash with 3% retained on sieve no. 325 and mean particle size of 15.7 microm, using liquid alkaline/ash ratios of 0.429-0.709, the sodium silicate/NaOH ratios of 0.67-1.5 and 7.5-12.5M NaOH. The incorporation of water improved the workability of geopolymer mortar more effectively than the use of napthalene-based superplasticizer with similar slight reduction in strengths. The addition of NaOH solution slightly improves the workability of the mix while maintaining the strength of the geopolymer mortars. PMID:19264400

  11. Radiative properties of ash and slag

    SciTech Connect

    Solomon, P.R.; Markham, J.R.; Best, P.E.; Yu, Zhen-Zhong.

    1990-10-01

    The objective of this program has been to make laboratory measurements of the radiative properties of ash and slag deposits that have been extracted from combustion devices. The program has resuited in measurements of radiative properlies of materials at high temperatures made by a technique employing a sample heatng deVice that is coupled to a FT-IR spectrometer to measure emission, directional-hemispherical transmission, and directional-hemispherical reflection of a sample. By this technique, the temperature at the measurement point and the spectral emittance (emissivity) of the surface are both obtained. These measurements are then related to the physical and chemical properties of the surface to determine what controls the radiative properlies. The measurements have shown that the physical state of a deposit (i.e. fused, sintered or packed particles) greatly influence the measured spectral emittance. The main accomplishments of the program are as follows: (1) Demonstration of measurement technique validation. (2) Measurements of spectral emittance for deposit samples as a function of temperature and morphology. (3) Accurate calculations of the optical properties of smooth and sintered surfaces based on the material's complex Index of refraction and the surface morphology.

  12. Rate limitations of lime dissolution into coal ash slag

    SciTech Connect

    L.K. Elliott; John A. Lucas; Jim Happ; John Patterson; Harry Hurst; Terry F. Wall

    2008-11-15

    The rate-limiting mechanisms of lime dissolution from a solid pellet into coal ash slag and synthetic slag was investigated using an experiment involving a rotating cylinder of lime in a liquid slag bath at temperatures of 1450-1650{degree}C. Scanning electron microscopy (SEM) analysis of the slag composition around the lime cylinder was used to determine the nature of the boundary layer surrounding the pellet and the calcium concentration profile. Predictions using shrinking core models of a cylindrical pellet were compared to experimental results, suggesting that diffusion through the slag boundary layer and the change of the phase of lime from solid to liquid in the boundary layer combine to limit the process. These results indicate that a combination of controlling steps: diffusion through the boundary layer and the phase change of lime from solid to liquid, must be considered when predicting lime dissolution rates. 24 refs., 5 figs., 3 tabs.

  13. Determination of slagging behavior of various coal ash samples by using DTF

    SciTech Connect

    Kim, H.T.; Choi, B.C.; Park, S.W.

    1999-07-01

    The objective of this study is to investigate slagging behavior of various ash samples with the conjunction to the properties of ashes and original coal such as concentration of each ash components, ash slagging temperature and slag viscosity. To simulate actual ash melting condition in coal combustion as well as gasification, DTF (drop tube furnace) is utilized for the acquisition of slag sample with different reaction condition. The sampled slag is photographed for the visual inspection and the shape of the slag is evaluated with ash properties. The sampled ash slag is also analyzed with XRD for the determination of phase transition during the ash melting. Furthermore, coal ashes are processed with Ash Fusion Determinator for the fusion temperature and High-Temperature Viscometer for the slag viscosity. Such ash-related properties are also determined by empirical formulation for the refinement of the result. So far, three different coal samples, Alaska, Datong, Cyprus are investigated. For the 3 ash samples, slag formation shows similar shape in combustion as well as gasification condition and completely different shape with different coal types. Alaska slag, which represents higher fluidity, is penetrated into alumina disk so that small half-cone shape of slag is produced. However, Cyprus slag is formed with more circular shape of sphere and Datong slag represents an in-between shape. More coal samples will be studied for the determination of slag behavior. The shape data will be analyzed with ash composition, fluidity behavior and ash fusion determination of original coal. Such relationship will be the baseline to determine the operation parameter of slag removal in the 3 ton/day coal gasifier located in the Ajou University, Suwon, Korea.

  14. Edaphological characteristics of unweathered and weathered fly ashes from Gondwana and lignite coal.

    PubMed

    Khandkar, U R; Gangwar, M S; Srivastava, P C; Singh, M

    1993-01-01

    Naturally weathered and unweathered samples of fly ashes produced from Gondwana and lignite coals were characterized for their edaphological properties. The particle size distribution in these fly ashes varied widely, and the percentage of [Formula: see text] size particles governed their water holding capacity. All fly ashes were noncoherent in the dry state and had lower particle density than quartz and mulite. The fly ashes were low in available N, but were sufficient in available P, K, Ca, Mg, S, Cu, Fe, Mn, Zn and B. Among the fly ashes, unweathered lignite fly ash was the richest source of K, Ca, Mg, S and Fe, while weathered lignite fly ash had the highest amounts of Mn, Zn and B. The pH of the fly ashes was closely related to the ratio of exchangeable Ca to exchangeable Al. The fly ashes were high in soluble salt, but were poor in cation exchange capacity. As an amendment to correct soil pH, the fly ashes had a poor buffering capacity. Weathering decreased the total Fe, available S and exchangeable Na percentages, but increased the organic C content of the fly ashes. Invariably, an excess of soluble salts and exchangeable Na could limit plant growth on fly ash dumps. Toxic levels of B and Al existed in only some fly ashes. PMID:15091893

  15. Behavior study of trace elements in pulverized lignite, bottom ash, and fly ash of Amyntaio power station, Greece.

    PubMed

    Megalovasilis, Pavlos; Papastergios, Georgios; Filippidis, Anestis

    2013-07-01

    The Kozani-Ptolemais-Amyntaio basin constitutes the principal coal field of Greece. Approximately 50% of the total power production of Greece is generated by five power stations operating in the area. Lignite samples, together with the corresponding fly ash and bottom ash were collected, over a period of 3 months, from the power plant of Amyntaio and analyzed for their content in 16 trace elements. The results indicate that Y, Nb, U, Rb, Zr, Ni, Pb, Ba, Zn, Sr, Cu, and Th demonstrate an organic affinity during the combustion of lignite, while V has an inorganic affinity. Three elements (Co, Cr, and Sc) show an intermediate affinity. PMID:23188071

  16. Potential products from North Dakota lignite fly ash. Final report

    SciTech Connect

    Anderson, G R

    1980-06-01

    Four major areas where fly ash can be used are explored. Concrete building blocks with fly ash replacing 50% of the portland cement have proven to be successful using current ASTM standards. Results in the ceramics area show that a ceramic-like product using fly ash and crushed glass with a small amount of clay as a green binder. Some preliminary results using sulfur ash in building materials are reported and with results of making wallboard from ash. (MHR)

  17. Utilization options for fly ash, bottom ash, and slag in Eastern Europe

    SciTech Connect

    Manz, O.E.

    1995-12-01

    Since 1967, at least six ash utilization symposiums have been held in the United States, with papers presented by several European authors on the utilization of coal by-products in Eastern Europe. There is currently over 80,000 megawatts of installed coal-fired capacity available in that region. Unfortunately, of the 117,778,000 tonnes of fly ash, bottom ash, and slag produced in Eastern Europe in 1989, only 13% was utilized. This paper outlines the research and levels and kinds of coal by-product utilization taking place in Eastern Europe since the late 1960s.

  18. Characterization of Slag, Fly Ash and Portland Cement for Saltstone

    SciTech Connect

    Harbour, J

    2006-02-01

    Batch-to-batch variability in the chemical and physical properties of the fly ash, slag and portland cement (binders) will be an ongoing concern over the many years that salt waste from Tank 50 will be processed into grout at the Saltstone Processing Facility. This batch-to-batch variability in the properties of the binder materials translates to variability in the fresh and cured properties of Saltstone. Therefore, it is important to quantify the batch-to-batch variability of the binder materials and the resultant variation in grout properties. This report is the starting point for that process by providing the baseline (reference point) binder properties to which future batches of binder materials can be compared. For this characterization effort, properties of fly ash, slag and portland cement were obtained and documented in this report. These properties included particle size distribution by laser light scattering and dry sieving, particle size and morphology by scanning electron microscopy, true, aerated and tapped densities, chemical composition, rheological properties of the water based slurries made from individual binder material, and volatility through thermogravimetric analysis and differential thermal analysis. The properties presented in this report also provide a baseline data set to assist in problem solving efforts when or if unanticipated and/or unwanted processing events occur at the Saltstone Processing Facility.

  19. Dissolution of lime into synthetic coal ash slags

    SciTech Connect

    Elliott, L.; Wang, Shen Mao; Wall, T.; Lucas, J.

    1996-12-31

    One of the alternate processes presently being investigated to produce electrical power from coal is Integrated Gasification Combined Cycle (IGCC). The ash that remains when the coal is gasified in this process, is removed by granulating the molten ash at 1400 - 1500{degrees}C, To reduce the melting temperature of the coal ash to this level, a flux, usually limestone, is added with the cow to the gasifier. The rate of dissolution of the flux is uncertain. This paper reports the investigation of the rate of time dissolution into synthetic coal ashes, consisting of SiO{sub 2}, Al{sub 2}O{sub 3} and CaO. Results previously reported have shown that the free dissolution of fine particles (50-200 {mu}m) is mass transfer controlled. To investigate forced dissolution, a high temperature viscometer was used to rotate a cylinder of lime in the molten slag for a given period. At temperatures between 1450{degrees}C and 1656{degrees}C, reaction products of 3CaO.SiO{sub 2}/3CaOAl{sub 2}O{sub 3}, 2CaO.SiO{sub 2}/3CaO.Al{sub 2}O{sub 3}/12CaO,7Al{sub 2}O{sub 3} form around the lime pellet. The concentration gradient involved in the mass transfer was defined, and initial studies of the diffusion coefficients were completed.

  20. Hydraulic activity of cement mixed with slag from vitrified solid waste incinerator fly ash.

    PubMed

    Lin, Kae-Long; Wang, Kuen-Sheng; Tzeng, Bor-Yu; Lin, Chung-Yei

    2003-12-01

    This study investigates the effects of the slag composition on the hydraulic activity in slag blended cement pastes that incorporate synthetic slag prepared by melting CaO-modified municipal solid waste incinerator fly ash. Two types of composition-modified slag were prepared for this study. First, fly ash was mixed with the modifier (CaO) at 5% and 15% (by weight) respectively, resulting in two fly ash mixtures. These mixtures were then melted at 1400 degrees C for 30 minutes and milled to produce two types of slag with different modifier contents, designated as C1-slag and C2-slag. These synthetic slags were blended with ordinary Portland cement at various weight ratios ranging from 10% to 40%. The synthetic slags presented sufficient hydraulic activity, and the heavy metal leaching concentrations all met the EPA's regulatory thresholds. The pore size distribution was determined by mercury intrusion porosimetry, and the results correlated with the compressive strength. The results also indicate that the incorporation of the 10% C1-slag tended to enhance the hydration degree of slag blended cement pastes during the early ages (3-28 days). However, at later ages, no significant difference in hydration degree was observed between ordinary Portland cement pastes and 10% C1-slag blended cement pastes. In the 10% C2-slag case, the trend was similar, but with a more limited enhancement during the early ages (3-28 days). Thus vitrified waste incinerator fly ash is a technically useful additive to cement, reducing the disposal needs for the toxic fly ash. PMID:14986718

  1. Managing metolachlor and atrazine leaching losses using lignite fly ash.

    PubMed

    Ghosh, Rakesh Kumar; Singh, Neera

    2012-10-01

    Application of low cost amendment for pesticide retention in soil is an important area of research in environmental sciences. The present study reports the potential of coal fly ash (Inderprastha and Badarpur), a waste from thermal power stations, for retaining soil applied metolachlor and atrazine within the application zone. Both the fly ashes were highly effective in reducing the leaching losses of metolachlor and atrazine and at 2% and 5% fly ash amendment levels the herbicides were retained in the top 15 cm profile of the column. However, fly ashes varied in their capacity in reducing the downward mobility of herbicides, as the Inderprastha fly ash was more effective than the Badarpur fly ash. Although fly ash contained heavy metals like Cr, Cu or Pb, but they were not detected in the leachate. Also, concentration of other metals like Zn, Mn and Fe in leachate decreased after fly ash amendment. Results of this study have implications in reducing the leaching losses of these herbicides in agricultural soils. PMID:22854744

  2. Study of slag content and properties after plasma melting of incineration ash

    NASA Astrophysics Data System (ADS)

    Park, Hyun-Seo

    2011-06-01

    The paper presents the investigation of plasma melting of the mixed bottom and fly incineration ash at various mixing ratios of the components. Chemical compound of the bottom and fly ash as well as the slag after its melting was analyzed by different methods, and the content of toxic components in them was determined. It is demonstrated that the direct disposal of the fly and bottom incineration ash may cause dioxin and heavy metal contamination of the environment. The influence of melted ash basicity on the resulting slag compound was studied. The mass balance of the melting process was defined. The tests were performed to determine the heavy-metals leaching from the ash and slag. It is also shown that the slag after plasma melting is dioxin-free and environmentally friendly.

  3. Characterizations of Deposited Ash During Co-Firing of White Pine and Lignite in Fluidized Bed Combustor

    NASA Astrophysics Data System (ADS)

    Shao, Yuanyuan; Zhu, Jesse; Preto, Fernando; Tourigny, Guy; Wang, Jinsheng; Badour, Chadi; Li, Hanning; Xu, Chunbao Charles

    Characterizations of ash deposits from co-firing/co-combusting of a woody biomass (i.e., white pine) and lignite coal were investigated in a fluidized-bed combustor using a custom designed air-cooled probe installed in the freeboard region of the reactor. Ash deposition behaviors on a heat transfer surface were comprehensively investigated and discussed under different conditions including fuel type, fuel blending ratios (20-80% biomass on a thermal basis), and moisture contents. For the combustion of 100% lignite, the compositions of the deposited ash were very similar to those of the fuel ash, while in the combustion of 100% white pine pellets or sawdust the deposited ash contained a much lower contents of CaO, SO3, K2O and P2O5 compared with the fuel ash, but the deposited ash was enriched with SiO2, Al2O3 and MgO. A small addition of white pine (20% on a heat input basis) to the coal led to the highest ash deposition rates likely due to the strong interaction of the CaO and MgO (from the biomass ash) with the alumina and silica (from the lignite ash) during the co-combustion process, evidenced by the detection of high concentrations of calcium/magnesium sulfates, aluminates and silicates in the ash deposits. Interestingly, co-firing of white pine pellets and lignite at a 50% blending ratio led to the lowest ash deposition rates. Ash deposition rates in combustion of fuels as received with a higher moisture content was found to be much lower than those of oven-dried fuels.

  4. Analyzing the Technology of Using Ash and Slag Waste from Thermal Power Plants in the Production of Building Ceramics

    NASA Astrophysics Data System (ADS)

    Malchik, A. G.; Litovkin, S. V.; Rodionov, P. V.; Kozik, V. V.; Gaydamak, M. A.

    2016-04-01

    The work describes the problem of impounding and storing ash and slag waste at coal thermal power plants in Russia. Recovery and recycling of ash and slag waste are analyzed. Activity of radionuclides, the chemical composition and particle sizes of ash and slag waste were determined; the acidity index, the basicity and the class of material were defined. The technology for making ceramic products with the addition of ash and slag waste was proposed. The dependencies relative to the percentage of ash and slag waste and the optimal parameters for baking were established. The obtained materials were tested for physical and mechanical properties, namely for water absorption, thermal conductivity and compression strength. Based on the findings, future prospects for use of ash and slag waste were identified.

  5. Radiative properties of ash and slag. Final report

    SciTech Connect

    Solomon, P.R.; Markham, J.R.; Best, P.E.; Yu, Zhen-Zhong

    1990-10-01

    The objective of this program has been to make laboratory measurements of the radiative properties of ash and slag deposits that have been extracted from combustion devices. The program has resuited in measurements of radiative properlies of materials at high temperatures made by a technique employing a sample heatng deVice that is coupled to a FT-IR spectrometer to measure emission, directional-hemispherical transmission, and directional-hemispherical reflection of a sample. By this technique, the temperature at the measurement point and the spectral emittance (emissivity) of the surface are both obtained. These measurements are then related to the physical and chemical properties of the surface to determine what controls the radiative properlies. The measurements have shown that the physical state of a deposit (i.e. fused, sintered or packed particles) greatly influence the measured spectral emittance. The main accomplishments of the program are as follows: (1) Demonstration of measurement technique validation. (2) Measurements of spectral emittance for deposit samples as a function of temperature and morphology. (3) Accurate calculations of the optical properties of smooth and sintered surfaces based on the material`s complex Index of refraction and the surface morphology.

  6. Industrial properties of lignitic and lignocellulosic fly ashes from Turkish sources

    SciTech Connect

    Demirbas, A.; Cetin, S.

    2006-01-21

    Fly ash is an inorganic matter from combustion of the carbonaceous solid fuels. More than half the electricity in Turkey is produced from lignite-fired power plants. This energy production has resulted in the formation of more than 13 million tons of fly ash waste annually. The presence of carbon in fly ash inducing common faults include adding unwanted black color and adsorbing process or product materials such as water and chemicals. One of the reasons for not using fly ash directly is its carbon content. For some uses carbon must be lower than 3%. Fly ash has been used for partial replacement of cement, aggregate, or both for nearly 70 years, and it is still used on a very limited scale in Turkey. The heavy metal content of industrial wastewaters is an important source of environmental pollution. Each of the three major oxides (SiO{sub 2} + Al{sub 2}O{sub 3} + Fe{sub 2}O{sub 3}) in fly ash can be ideal as a metal adsorbent.

  7. Acidification-neutralization processes in a lignite mine spoil amended with fly ash or limestone.

    PubMed

    Seoane, S; Leirós, M C

    2001-01-01

    A laboratory experiment was conducted to investigate the longterm effects of amending sulfide-rich lignite mine spoil with fly ash (originating from a coal-fired power station and largely comprised of aluminosilicates) and/or agricultural limestone. The experiment was carried out with soil moisture maintained at field capacity or alternate cycles of wetting and drying. Results obtained suggest that the principal acidification processes were oxidation of sulfide and formation of hydroxysulfate (FeOHSO4), whereas the main neutralization processes were weathering of aluminosilicates in fly ash-treated samples and dissolution of calcium carbonate in limestone-treated samples. The highest dose of limestone rapidly raised the pH of the spoil, but this increase was not maintained throughout the one-year experiment. In contrast, fly ash-treated samples showed a more sustained increase in pH, attributable to the gradual weathering of aluminosilicates. The best results (i.e., good short- and long-term neutralization) were obtained in samples treated with both fly ash and limestone. The low liming capacity of the fly ash (47.85 cmol kg(-1)) means that it must be used in large quantities, an advantage in achieving the further aim of disposing of the fly ash. PMID:11476521

  8. Biofunctional Characteristics of Lignite Fly Ash Modified by Humates: A New Soil Conditioner

    PubMed Central

    Chassapis, Konstantinos; Roulia, Maria; Vrettou, Evangelia; Fili, Despina; Zervaki, Monica

    2010-01-01

    Fly ash superficially modified with humic substances from the Megalopolis lignitic power plant was prepared and evaluated for agricultural uses. UV-vis spectrophotometry and IR spectroscopy revealed that fly ash shows high sorption efficiency towards humic substances. Adsorption proceeds stepwise via strong Coulombic and hydrophophic forces of attraction between guest and host materials. Langmuir, Freundlich, BET, Harkins-Jura, and Dubinin-Radushkevich isotherm models were employed to evaluate the ongoing adsorption and shed light to the physicochemical properties of the sorbent-adsorbate system. Humic substances desorption and microbial cultivation experiments were also carried out to examine the regeneration of the humates under washing and explore the possibility of this material acclimatizing in real soil conditions, both useful for biofunctional agricultural applications. PMID:20592758

  9. Biofunctional characteristics of lignite fly ash modified by humates: a new soil conditioner.

    PubMed

    Chassapis, Konstantinos; Roulia, Maria; Vrettou, Evangelia; Fili, Despina; Zervaki, Monica

    2010-01-01

    Fly ash superficially modified with humic substances from the Megalopolis lignitic power plant was prepared and evaluated for agricultural uses. UV-vis spectrophotometry and IR spectroscopy revealed that fly ash shows high sorption efficiency towards humic substances. Adsorption proceeds stepwise via strong Coulombic and hydrophophic forces of attraction between guest and host materials. Langmuir, Freundlich, BET, Harkins-Jura, and Dubinin-Radushkevich isotherm models were employed to evaluate the ongoing adsorption and shed light to the physicochemical properties of the sorbent-adsorbate system. Humic substances desorption and microbial cultivation experiments were also carried out to examine the regeneration of the humates under washing and explore the possibility of this material acclimatizing in real soil conditions, both useful for biofunctional agricultural applications. PMID:20592758

  10. Refinement of procedures for analysis and construction of hydraulicked ash-slag dumps to improve their in-service safety

    SciTech Connect

    Frolov, A. N.

    2013-03-15

    Solutions are proposed for enhancement of the in-service safety of hydraulicked ash-slag dumps with consideration of their hydrothermal regime. An assessment is given for the minimum dimensions of the settling basins and top surface of ash-slag dumps.

  11. Alkali-Activated Fly ash-slag Cement based nuclear waste forms

    SciTech Connect

    Jiang, W.; Wu, X.; Roy, D.M.

    1993-12-31

    This paper is based on the results of an in-progress research project on Alkali-Activated Cement System at MRL. The objective of this research is to establish the potential for large volume use of fly ash and slag as main components of the cement system. Alkali-activated Fly ash-slag Cement (AFC) was studied as a matrix for immobilization of nuclear waste. AFC is characterized by high early strength, high ultimate strength, low porosity, lower solubilities of the hydrates, and high resistance to chemical corrosion as well as to freezing and thawing. All these advanced properties are particularly favorable to the immobilization the nuclear wastes.

  12. Environmental assessment of remedial action at the inactive uraniferous lignite ashing sites at Belfield and Bowman, North Dakota

    SciTech Connect

    Not Available

    1993-09-01

    The Uranium Mill Tailings Radiation Control Act (UMTRCA) of 1978 authorized the US Department of Energy (DOE) to perform remedial actions at Belfield and Bowman inactive lignite ashing sites in southwestern North Dakota to reduce the potential public health impacts from the residual radioactivity remaining at the sites. The US Environmental Protection Agency (EPA) promulgated standards (40 CFR 192) that contain measures to control the residual radioactive materials and other contaminated materials, and proposed standards to protect the groundwater from further degradation. Remedial action at the Belfield and Bowman sites must be performed in accordance with these standards and with the concurrence of the US Nuclear Regulatory Commission (NRC) and the state of North Dakota. The Belfield and Bowman designated sites were used by Union Carbide and Kerr-McGee, respectively, to process uraniferous lignite in the 1960s. Uranium-rich ash from rotary kiln processing of the lignite was loaded into rail cars and transported to uranium mills in Rifle, Colorado, and Ambrosia Lake, New Mexico, respectively. As a result of the ashing process, there is a total of 158,400 cubic yards (yd{sup 3}) [121,100 cubic meters (m{sup 3})] of radioactive ash-contaminated soils at the two sites. Windblown ash-contaminated soil covers an additional 21 acres (8.5 ha) around the site, which includes grazing land, wetlands, and a wooded habitat.

  13. Reactivity of alkaline lignite fly ashes towards CO{sub 2} in water

    SciTech Connect

    Martin Back; Michael Kuehn; Helge Stanjek; Stefan Peiffer

    2008-06-15

    The reaction kinetics between alkaline lignite fly ashes and CO{sub 2} (pCO{sub 2} = 0.01-0.03 MPa) were studied in a laboratory CO{sub 2} flow-through reactor at 25-75{sup o}C. The reaction is characterized by three phases that can be separated according to the predominating buffering systems and the rates of CO{sub 2} uptake. Phase I (pH > 12, < 30 min) is characterized by the dissolution of lime, the onset of calcite precipitation and a maximum uptake, the rate of which seems to be limited by dissolution of CO{sub 2}. Phase II (pH < 10.5, 10-60 min) is dominated by the carbonation reaction. CO{sub 2} uptake in phase III (pH < 8.3) is controlled by the dissolution of periclase (MgO) leading to the formation of dissolved magnesium-bicarbonate. Phase I could be significantly extended by increasing the solid-liquid ratios and temperature, respectively. At 75{sup o}C the rate of calcite precipitation was doubled leading to the neutralization of approximately 0.23 kg CO{sub 2} per kg fly ash within 4.5 h, which corresponds to nearly 90% of the total acid neutralizing capacity. 21 refs., 5 figs., 1 tab.

  14. The influence of nickel slag aggregate concentration to compressive and flexural strength on fly ash-based geopolymer composite

    NASA Astrophysics Data System (ADS)

    Sujiono, E. H.; Setiawan, A.; Husain, H.; Irhamsyah, A.; Samnur, S.; Subaer, S.

    2016-04-01

    Fly ash-based geopolymer with nickel slag aggregate has been successfully produced. Fly ash and nickel slag were obtained from Bosowa Jeneponto Power Plant and PT. Vale Indonesia, respectively. This research aims to investigate the influence of nickel slag concentration to compressive strength, flexural strength, and microstructure of geopolymer composite. The increment of nickel slag aggregate on fly ash was relative to the weight of samples. Geopolymer composite were synthesized by using alkali activated method, cured at temperature of 70 °C for 1 hour. The resulting composites were left at room temperature for 14 days, before compressive and flexural strength were performed. The results showed that the addition of nickel slag aggregate was found to increase the compressive strength of the material. The optimum compressive strength was 14.81 MPa with the addition of 10% aggregate. The optimum flexural strength was 2.63 MPa with the addition of 15% aggregate.

  15. Slags and ashes from municipal waste incineration in Poland - mineralogical and chemical composition

    NASA Astrophysics Data System (ADS)

    Kowalski, Piotr; Michalik, Marek

    2013-04-01

    In the next few years there will be a large change in the waste management system in Poland. Its primary aim will be reduction of the amount of landfilled waste by enhancing level of recycling, waste segregation, composting of biomass and incineration. The biggest investment during this transformation is construction of nine incinerators with assumed slags production around 200 thousand tons per year. Slag production is accompanied by fly ash generating. This ash can be a valuable raw material as fly ash from the power industry. Waste management system transformation will cause big increase in slag production in comparison to the present amount and will require taking necessary steps to ensure environmental safety. For this purpose, studies of slags and fly ashes in terms of environmental risk and potential impact on human health are significant. The object of the study are fly ashes and slags produced in the biggest municipal waste incineration power plant in Poland. Two series of samples obtained in municipal waste incineration process were studied in order to characterize mineralogical and chemical composition and to determine the concentrations of heavy metals and their possible negative environmental impact. Characteristics of these materials will be the basis for determining their value in application, for example in building industry. Mineralogical characteristic of slags was based on X-ray diffraction. Characteristic of structures and forms of occurrence of mineral phases was based on the optical microscopy and SEM imaging coupled with EDS analysis. Chemical analysis were performed using ICP-MS/ICP-AES methods. They allowed to follow variability between studied samples and gave basic information about metals. Metals in samples of slag and ashes are present as component of mineral phases and in the form of metallic inclusions in glass or minerals. Potentially hazardous concentrations for environment are observed for copper (330-4900ppm), zinc (1500-8100ppm

  16. Gel nanostructure in alkali-activated binders based on slag and fly ash, and effects of accelerated carbonation

    SciTech Connect

    Bernal, Susan A.; Provis, John L.; Walkley, Brant; San Nicolas, Rackel; Gehman, John D.; Brice, David G.; Kilcullen, Adam R.; Duxson, Peter; Deventer, Jannie S.J. van

    2013-11-15

    Binders formed through alkali-activation of slags and fly ashes, including ‘fly ash geopolymers’, provide appealing properties as binders for low-emissions concrete production. However, the changes in pH and pore solution chemistry induced during accelerated carbonation testing provide unrealistically low predictions of in-service carbonation resistance. The aluminosilicate gel remaining in an alkali-activated slag system after accelerated carbonation is highly polymerised, consistent with a decalcification mechanism, while fly ash-based binders mainly carbonate through precipitation of alkali salts (bicarbonates at elevated CO{sub 2} concentrations, or carbonates under natural exposure) from the pore solution, with little change in the binder gel identifiable by nuclear magnetic resonance spectroscopy. In activated fly ash/slag blends, two distinct gels (C–A–S–H and N–A–S–H) are formed; under accelerated carbonation, the N–A–S–H gel behaves comparably to fly ash-based systems, while the C–A–S–H gel is decalcified similarly to alkali-activated slag. This provides new scope for durability optimisation, and for developing appropriate testing methodologies. -- Highlights: •C-A-S-H gel in alkali-activated slag decalcifies during accelerated carbonation. •Alkali-activated fly ash gel changes much less under CO{sub 2} exposure. •Blended slag-fly ash binder contains two coexisting gel types. •These two gels respond differently to carbonation. •Understanding of carbonation mechanisms is essential in developing test methods.

  17. Hazard rating of ash and slag dumps of thermal power plants firing Kuznetskii coal

    SciTech Connect

    E.P. Dik; A.N. Soboleva

    2006-03-15

    Results of a study of the degree of toxicity and of the hazard rating of ash and slag waste due to firing Kuznetskii coals at thermal power plants are presented. Computation shows and biological tests prove that the waste belongs to the fifth hazard class, i.e., is virtually safe. Comparison of the results obtained with foreign data shows that the waste in question belongs to the safe category in accordance with foreign standards as well.

  18. Management of Lignite Fly Ash for Improving Soil Fertility and Crop Productivity

    NASA Astrophysics Data System (ADS)

    Ram, Lal C.; Srivastava, Nishant K.; Jha, Sangeet K.; Sinha, Awadhesh K.; Masto, Reginald E.; Selvi, Vetrivel A.

    2007-09-01

    Lignite fly ash (LFA), being alkaline and endowed with excellent pozzolanic properties, a silt loam texture, and plant nutrients, has the potential to improve soil quality and productivity. Long-term field trials with groundnut, maize, and sun hemp were carried out to study the effect of LFA on growth and yield. Before crop I was sown, LFA was applied at various doses with and without press mud (an organic waste from the sugar industry, used as an amendment and source of nutrients). LFA with and without press mud was also applied before crops III and V were cultivated. Chemical fertilizer, along with gypsum, humic acid, and biofertilizer, was applied in all treatments, including the control. With one-time and repeat applications of LFA (with and without press mud), yield increased significantly (7.0-89.0%) in relation to the control crop. The press mud enhanced the yield (3.0-15.0%) with different LFA applications. The highest yield LFA dose was 200 t/ha for one-time and repeat applications, the maximum yield being with crop III (combination treatment). One-time and repeat application of LFA (alone and in combination with press mud) improved soil quality and the nutrient content of the produce. The highest dose of LFA (200 t/ha) with and without press mud showed the best residual effects (eco-friendly increases in the yield of succeeding crops). Some increase in trace- and heavy-metal contents and in the level of γ-emitters in soil and crop produce, but well within permissible limits, was observed. Thus, LFA can be used on a large scale to boost soil fertility and productivity with no adverse effects on the soil or crops, which may solve the problem of bulk disposal of fly ash in an eco-friendly manner.

  19. Management of lignite fly ash for improving soil fertility and crop productivity

    SciTech Connect

    Ram, L.C.; Srivastava, N.K.; Jha, S.K.; Sinha, A.K.; Masto, R.E.; Selvi, V.A.

    2007-09-15

    Lignite fly ash (LFA), being alkaline and endowed with excellent pozzolanic properties, a silt loam texture, and plant nutrients, has the potential to improve soil quality and productivity. Long-term field trials with groundnut, maize, and sun hemp were carried out to study the effect of LFA on growth and yield. Before crop I was sown, LFA was applied at various doses with and without press mud (an organic waste from the sugar industry, used as an amendment and source of nutrients). LFA with and without press mud was also applied before crops III and V were cultivated. Chemical fertilizer, along with gypsum, humic acid, and bioferfertilizer, was applied in all treatments, including the control. With one-time and repeat applications of LFA (with and without press mud), yield increased significantly (7.0-89.0%) in relation to the control crop. The press mud enhanced the yield (3.0-15.0%) with different LFA applications. One-time and repeat application of LFA (alone and in combination with press mud) improved soil quality and the nutrient content of the produce. The highest dose of LFA (200 t/ha) with and without press mud showed the best residual effects (eco-friendly increases in the yield of succeeding crops). Some increase in trace- and heavy metal contents and in the level of gamma-emitters in soil and crop produce, but well within permissible limits, was observed. Thus, LFA can be used on a large scale to boost soil fertility and productivity with no adverse effects on the soil or crops, which may solve the problem of bulk disposal of fly ash in an eco-friendly manner.

  20. Management of lignite fly ash for improving soil fertility and crop productivity.

    PubMed

    Ram, Lal C; Srivastava, Nishant K; Jha, Sangeet K; Sinha, Awadhesh K; Masto, Reginald E; Selvi, Vetrivel A

    2007-09-01

    Lignite fly ash (LFA), being alkaline and endowed with excellent pozzolanic properties, a silt loam texture, and plant nutrients, has the potential to improve soil quality and productivity. Long-term field trials with groundnut, maize, and sun hemp were carried out to study the effect of LFA on growth and yield. Before crop I was sown, LFA was applied at various doses with and without press mud (an organic waste from the sugar industry, used as an amendment and source of nutrients). LFA with and without press mud was also applied before crops III and V were cultivated. Chemical fertilizer, along with gypsum, humic acid, and biofertilizer, was applied in all treatments, including the control. With one-time and repeat applications of LFA (with and without press mud), yield increased significantly (7.0-89.0%) in relation to the control crop. The press mud enhanced the yield (3.0-15.0%) with different LFA applications. The highest yield LFA dose was 200 t/ha for one-time and repeat applications, the maximum yield being with crop III (combination treatment). One-time and repeat application of LFA (alone and in combination with press mud) improved soil quality and the nutrient content of the produce. The highest dose of LFA (200 t/ha) with and without press mud showed the best residual effects (eco-friendly increases in the yield of succeeding crops). Some increase in trace- and heavy-metal contents and in the level of gamma-emitters in soil and crop produce, but well within permissible limits, was observed. Thus, LFA can be used on a large scale to boost soil fertility and productivity with no adverse effects on the soil or crops, which may solve the problem of bulk disposal of fly ash in an eco-friendly manner. PMID:17705037

  1. Modelling chloride diffusion in concrete: Effect of fly ash and slag

    SciTech Connect

    Thomas, M.D.A.; Bamforth, P.B.

    1999-04-01

    The ability of concrete to resist the penetration of chloride ions is a critical parameter in determining the service life of steel-reinforced concrete structures exposed to deicing salts or marine environments. Data from long-term field and laboratory studies of concrete exposed to chloride environments were analyzed using a chloride transport model developed at the University of Toronto. The results show that the incorporation of fly ash and slag may have little impact on transport properties determined at early ages (e.g., 28 days), but can lead to order of magnitude improvements in the long term. This means that the rate of chloride penetration during the first 6 months or so of exposure is similar for concretes with and without these materials. However, after a few years of exposure, chloride ingress slows to a much-decreased rate in fly ash and slag concretes, leading to dramatic increases in the predicted service life. Predictive models and laboratory test methods for determining chloride ingress should take account of the time-dependent nature of the transport processes in concrete, especially when supplementary cementing materials, such as fly ash or slag, are used.

  2. Management of mine spoil for crop productivity with lignite fly ash and biological amendments.

    PubMed

    Ram, L C; Srivastava, N K; Tripathi, R C; Jha, S K; Sinha, A K; Singh, G; Manoharan, V

    2006-04-01

    Long-term field trials using lignite fly ash (LFA) were carried out in rice crops during the period 1996-2000 at Mine I, Neyveli Lignite Corporation, Tamil Nadu. LFA, being alkaline and endowed with an excellent pozzolanic nature, silt loam texture, and plant nutrients, has the potential to improve the texture, fertility, and crop productivity of mine spoil. The rice crops were the first, third, fifth, and sixth crops in rotation. The other crops, such as green gram (second) and sun hemp (fourth), were grown as green manure. For experimental trials, LFA was applied at various dosages (0, 5, 10, 20, 50, 100, and 200 t/ha), with and without press mud (10 t/ha), before cultivation of the first crop. Repeat applications of LFA were made at the same dosages in treatments of up to 50 t/ha (with and without press mud) before cultivation of the third and fifth crops. Press mud, a lightweight organic waste product from the sugar industry, was used as an organic amendment and source of plant nutrients. Also, a recommended dosage of chemical fertilizer, along with gypsum, humic acid, and biofertilizer as supplementing agents, was applied in all the treatments, including control. With one-time and repeat applications of LFA, from 5 to 20 t/ha (with and without press mud), the crop yield (grain and straw) increased significantly (p < 0.05), in the range from 3.0 to 42.0% over the corresponding control. The maximum yield was obtained with repeat applications of 20 t/ha of LFA with press mud in the third crop. The press mud enhanced the yield in the range of 1.5-10.2% with various dosages of LFA. The optimum dosage of LFA was 20 t/ha for both one-time and repeat applications. Repeat applications of LFA at lower dosages of up to 20 t/ha were more effective in increasing the yield than the corresponding one-time applications of up to 20 t/ha and repeat applications at 50 t/ha. One-time and repeat applications of LFA of up to 20 t/ha (with and without press mud), apart from

  3. Market Assessment and Demonstration of Lignite FBC Ash Flowable Fill Applications

    SciTech Connect

    Alan E. Bland

    2003-09-30

    Montana-Dakota Utilities (MDU) and Western Research Institute (WRI) have been developing flowable fill materials formulated using ash from the Montana-Dakota Utilities R. M. Heskett Station in Mandan, North Dakota. MDU and WRI have partnered with the U.S. Department of Energy (DOE) and the North Dakota Industrial Commission (NDIC) to further the development of these materials for lignite-fired fluidized-bed combustion (FBC) facilities. The MDU controlled density fill (CDF) appears to be a viable engineering material and environmentally safe. WRI is pursuing the commercialization of the technology under the trademark Ready-Fill{trademark}. The project objectives were to: (1) assess the market in the Bismarck-Mandan area; (2) evaluate the geotechnical properties and environmental compatibility; and (3) construct and monitor demonstrations of the various grades of flowable fill products in full-scale demonstrations. The scope of initial phase of work entailed the following: Task I--Assess Market for MDU Flowable Fill Products; Task II--Assess Geotechnical and Environmental Properties of MDU Flowable Fill Products; and Task III--Demonstrate and Monitor MDU Flowable Fill Products in Field-Scale Demonstrations. The results of these testing and demonstration activities proved the following: (1) The market assessment indicated that a market exists in the Bismarck-Mandan area for structural construction applications, such as sub-bases for residential and commercial businesses, and excavatable fill applications, such as gas line and utility trench filling. (2) The cost of the MDU flowable fill product must be lower than the current $35-$45/cubic yard price if it is to become a common construction material. Formulations using MDU ash and lower-cost sand alternatives offer that opportunity. An estimated market of 10,000 cubic yards of MDU flowable fill products could be realized if prices could be made competitive. (3) The geotechnical properties of the MDU ash-based flowable

  4. Baseline risk assessment of ground water contamination at the inactive uraniferous lignite ashing site near Bowman, North Dakota

    SciTech Connect

    Not Available

    1994-11-01

    This baseline risk assessment of ground water contamination at the inactive uraniferous lignite ashing site near Bowman, North Dakota, evaluates the potential impacts to public health or the environment from contaminated ground water at this site. This contamination is a result of the uraniferous lignite ashing process, when coal containing uranium was burned to produce uranium. Potential risk is quantified only for constituents introduced by the processing activities and not for the constituents naturally occurring in background ground water in the site vicinity. Background ground water, separate from any site-related contamination, imposes a percentage of the overall risk from ground water ingestion in the Bowman site vicinity. The US Department of Energy (DOE) Uranium Mill Tailings Remedial Action (UMTRA) Project is developing plans to address soil and ground water contamination at the site. The UMTRA Surface Project involves the determination of the extent of soil contamination and design of an engineered disposal cell for long-term storage of contaminated materials. The UMTRA Ground Water Project evaluates ground water contamination. Based on results from future site monitoring activities as defined in the site observational work plan and results from this risk assessment, the DOE will propose an approach for managing contaminated ground water at the Bowman site.

  5. Magnetic tracing of coal slag and ash in a river basin

    NASA Astrophysics Data System (ADS)

    Appel, Erwin; Frančišković-Bilinski, Stanislav; Zhang, Qi; Rösler, Wolfgang; Zhang, Qian

    2016-04-01

    Atmospheric distribution of pollutants by magnetic means has been extensively studied, but only little is known about pollution-related magnetic signatures for aquatic transport. The case of a textile factory in Croatia that released heavy-metal polluted and highly magnetic ash and slag material from coal burning into Mrežnica River for 110 years (1884-1994) represents an ideal target for studying principles of magnetic tracing through a river system. Samples from the riverside close to the factory show high concentrations of magnetite (mass-specific susceptibility χ ˜1-4 x10‑5 m3kg‑1) with low frequency dependence (χfd% <3%). However, quantitative detection of slag and ash transport in the downstream direction through the riverbed is hindered by extremely variable magnetic properties of the river sediments, presumably due to hydrodynamic sorting. Surface mapping of χ on riverbanks ˜3 km downstream of the factory reveals clear evidence for substantial distribution of slag and ash materials in the river basin due to flooding; the affected area reaches to >100 m from the riverside. The spatial pattern of shallow vertical sections of χ (surface to ˜0.5 m depth) shows different layers of coal burning residues which may even allow discriminating different flooding events (historical flooding). In order to assess the possible influence of fly ash from the factory, we studied vertical soil profiles at locations which cannot be reached by floods. These (red) soils, formed on limestones, are strongly magnetic (χ >10‑6 m3kg‑1). Despite this strong natural magnetic signals, the depth dependence of χfd% and characteristic chemical properties (sulfur content, Ni/Cu ratio) as well as the dependence of the vertical χ distribution with distance to the point source indicate a contribution of fly ash to soil contamination near the factory (within about one kilometer). The presently available results indicate that with a strong magnetic point source as in the case

  6. Slags

    NASA Astrophysics Data System (ADS)

    Somerville, Michael; Sun, Shouyi; Jahanshahi, Sharif

    2014-12-01

    New measurements on solubility of copper and redox equilibria in magnesia-saturated calcium ferrite-based slags are presented. These data were obtained from equilibrium experiments at 1573 K (1300 °C) and over a range of oxygen partial pressures of 10-11 to 10-5 atm, through equilibrating the slag with metallic copper in magnesia crucibles under a flowing Ar-CO-CO2 gas mixture. At low oxygen partial pressures, copper was found to dissolve into slag as a univalent species (CuO0.5) with a linear dependence on the oxygen partial pressure (in logarithm), with a slope of 0.23. At higher oxygen partial pressures (>10-7 atm), the data suggest a divalent copper species becomes significant (CuO) and causes the dependence on oxygen partial pressure to increase. The determination of the Fe3+/Fe2+ ratio in the slag was effected by the cuprous (Cu+) content, which acts to increase the apparent ferrous (Fe2+) content during acid digestion. A correction procedure was applied to the Fe3+/Fe2+ ratio based on the calculated Cu+ content of the slag. The procedure assumes that the activity coefficients of CuO0.5 and CuO (and γ CuO) in these slags are independent of oxygen partial pressure. The calculated activity coefficients of CuO0.5 and CuO were 3.43 and 0.29, respectively. The corrected Fe3+/Fe2+ ratio had a linear dependence of 0.17 on the oxygen partial pressure over the entire oxygen partial pressure range. This agrees with similar data from the literature.

  7. Influence of the composition of cement kiln dust on its interaction with fly ash and slag

    SciTech Connect

    Chaunsali, Piyush; Peethamparan, Sulapha

    2013-12-15

    Cement kiln dust (CKD), a by-product of the cement industry, contains significant amounts of alkali, free lime, chloride and sulfate. Wide variation reported in the chemical composition of CKDs limits their potential application as a sustainable binder component in concrete. In the current study, the performance of two different CKDs as components in a novel binder is evaluated. Several binders are developed by blending CKDs with fly ash or slag. Binders with 70% CKD were prepared at a water-to-binder ratio of 0.4, and heat-cured at 75 °C to accelerate the strength development. The hydration progress was monitored using X-ray diffraction, and morphological examination was performed using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Ettringite and calcium aluminosilicate hydrate (C-A-S-H) were identified as the main hydration products in the hardened binder system. Strength development of CKD-based binder was found to be significantly influenced by its free lime and sulfate contents. -- Highlights: •Interaction of cement kiln dust with fly ash and slag was explored. •CKD with higher free lime and sulfate content increased the strength of binder. •C-S-H like reaction gel with fibrillar morphology is observed in CKD-based binders.

  8. Ash and slag characterization. Final report for the period ending March 31, 1986

    SciTech Connect

    Falcone, S K

    1986-06-01

    A procedure was developed for mine sampling and the storage of standard coals under argon. In total, 53 coals were collected and are also available to other DOE supported projects at the Center. Task 2 was the study of mineral transformation during ashing of low-rank coals. Results of this study verified the importance of organically-bound alkalies, specifically calcium and sodium, in forming low-melting temperature aluminosilicates (i.e., melilites). Task 3 highlighted the viscosity studies on the molten ash of low-rank coals. A major part of this study involved the modification of the Urbain equation so that it can be used to predict the Newtonian behavior of low-rank coal slags. In addition, the effects of iron and sodium on viscosity, hysteresis, and the nature of the non-Newtonian flow were examined. Task 4 comprised the identification of volatilized species evolved during the combustion of selected low-rank coals. In each case sodium, potassium and sulfur were found to be major components of the condensed volatiles. Verification of their volatility on an experimental basis has significance in their possible contributions to forming new solid and liquid phases at high temperatures. Finally Task 5 evaluated the use of various sessile drop techniques to determine the surface tension of low-rank coal slags. Results show that meaningful surface tension measurements can be obtained with the use of vitreous carbon as a substrate.

  9. Mineralogical composition of boiler fouling and slagging deposits and their relation to fly ashes: the case of Kardia power plant.

    PubMed

    Kostakis, George

    2011-01-30

    Slagging and fouling deposits from a pulverized lignite fired steam generating unit of the Kardia power plant (West Macedonia, Greece) were mineralogically investigated. The structure and cohesion of these deposits varied, usually depending on the level height of the boiler unit where they were formed. Some of the deposits had complex phase composition. The dominant components of the deposits of the burner zone and of the lower and intermediate boiler zones were the amorphous, anhydrite and hematite, while those of the highest levels contained amorphous, and anhydrite. Furthermore, in deposits formed in various other boiler areas gehlenite, anorthite, diopside, quartz, Ca(2)SiO(4), brownmillerite and other crystalline phases were also identified, usually in low amounts or in traces. The major part of the phases constituting the deposits were formed in the boiler, since only a minor part derived from the unreacted minerals present in lignite. Anhydrite was generated from the reaction of SO(2) with CaO formed mainly by the calcination of calcite as well as from dehydration of gypsum contained in lignite, while hematite was produced mainly from the oxidation of pyrite. The calcium-containing silicates formed in the boiler were mainly the products of reactions between CaO and minerals contained in the lignite. PMID:21035255

  10. Self-degradable Slag/Class F Fly Ash-Blend Cements

    SciTech Connect

    Sugama, T.; Warren, J.; Butcher, T.; Lance Brothers; Bour, D.

    2011-03-01

    Self-degradable slag/Class F fly ash blend pozzolana cements were formulated, assuming that they might serve well as alternative temporary fracture sealers in Enhanced Geothermal System (EGS) wells operating at temperatures of {ge} 200 C. Two candidate formulas were screened based upon material criteria including an initial setting time {ge} 60 min at 85 C, compressive strength {ge} 2000 psi for a 200 C autoclaved specimen, and the extent of self-degradation of cement heated at {ge} 200 C for it was contacted with water. The first screened dry mix formula consisted of 76.5 wt% slag-19.0 wt% Class F fly ash-3.8 wt% sodium silicate as alkali activator, and 0.7 wt% carboxymethyl cellulose (CMC) as the self-degradation promoting additive, and second formula comprised of 57.3 wt% slag, 38.2 wt% Class F fly ash, 3.8 wt% sodium silicate, and 0.7 wt% CMC. After mixing with water and autoclaving it at 200 C, the aluminum-substituted 1.1 nm tobermorite crystal phase was identified as hydrothermal reaction product responsible for the development of a compressive strength of 5983 psi. The 200 C-autoclaved cement made with the latter formula had the combined phases of tobermorite as its major reaction product and amorphous geopolymer as its minor one providing a compressive strength of 5271 psi. Sodium hydroxide derived from the hydrolysis of sodium silicate activator not only initiated the pozzolanic reaction of slag and fly ash, but also played an important role in generating in-situ exothermic heat that significantly contributed to promoting self-degradation of cementitious sealers. The source of this exothermic heat was the interactions between sodium hydroxide, and gaseous CO{sub 2} and CH{sub 3}COOH by-products generated from thermal decomposition of CMC at {ge} 200 C in an aqueous medium. Thus, the magnitude of this self-degradation depended on the exothermic temperature evolved in the sealer; a higher temperature led to a sever disintegration of sealer. The exothermic

  11. Influence of coal ash and slag dumping on dump waste waters of the Kostolac power plants (Serbia)

    SciTech Connect

    Popovic, A.; Djinovic, J.

    2006-10-01

    The content of selected trace and major elements in the river water used for transport, as well as in the subcategories of the waste waters (overflow and drainage) were analyzed in order to establish the influence of transport and dumping of coal ash and slag from the 'Kostolac A' and 'Kostolac B' power plants located 100 km from Belgrade (Serbia). It was found that during transport of coal ash and slag to the dump, the water used for transport becomes enriched with manganese, nickel, zinc, chromium, vanadium, titanium, cobalt, arsenic, aluminum, and silicon, while more calcium, iron, cadmium, and lead are adsorbed by the ash and slag than is released from them. There is also an equilibrium between the release and adsorption processes of copper and magnesium during transport. The vertical penetration of the water used for transport results in a release of calcium, magnesium, manganese, and cadmium to the environment, while iron, nickel, zinc, chromium, copper, lead, vanadium, titanium, cobalt, and arsenic are adsorbed by the fractions of coal ash and slag in the dump.

  12. The pH-dependent contaminant leaching from the copper smelter fly ash and slag

    NASA Astrophysics Data System (ADS)

    Jarosikova, Alice; Ettler, Vojtech; Mihaljevic, Martin; Penizek, Vit

    2014-05-01

    Metallurgical wastes produced during smelting processes represent a potential risk of environmental contamination, depending particularly on the content and mobility of the elements contained. Due to leaching, serious environmental impact especially in contaminated soil systems in the vicinity of the smelting plants may occur. In this respect two potentially hazardous metallurgical wastes from the copper smelter Tsumeb (Namibia, Africa) were investigated by laboratory leaching experiments. The leaching behaviours of (i) Ausmelt slag from Cu smelting (9500 ppm As, 24000 ppm Cu, 10200 ppm Pb, 24500 ppm Zn; mineralogy: glass, fayalite, spinel, metallic/sulphide droplets) and (ii) fly ash from Cu smelter bag house filters (43.7 wt% As, 13000 ppm Cu, 39700 ppm Pb, 20000 ppm Zn; mineralogy: arsenolite, galena, gypsum, litharge, anglesite) were studied using a 48-h pH-static leaching test (CEN/TS 14997). The release of metals/metalloids at a range of pH 3-12, investigation of changes in mineralogical composition and PHREEQC speciation-solubility modelling were used to understand processes governing the contaminant leaching from these waste materials. It was observed that the contaminant leaching was highly pH-dependent. The release of metals from slag corresponded to "L-type" leaching curve with Cu being the key contaminant leached (up to 1780 mg/kg). In contrast, As was highly leached also in alkaline conditions (31-173 mg/kg) and significantly exceeded the limit value for hazardous waste materials in all cases (25 mg/kg). Fly ash was found to be extremely reactive in terms of the As release with a "J-type" leaching curve indicating the highest leaching at pH of 11 and 12 (up to 314 g/kg). Arsenic was considered to be the most important contaminant for both waste materials and its release can represent a risk for the environment, especially in case, where the fly ash- or slag-derived particulates are deposited into the soil systems. This study was supported by the Czech

  13. Radiative properties of ash and slag. Sixth quarterly report, November 1, 1988--January 31, 1989

    SciTech Connect

    Solomon, P.R.; Markham, J.R.

    1989-12-31

    Thermal radiation plays a key role in the operation and efficiency of combustion systems, accounting for over 90% of the heat transfer. The analysis of radiative heat transfer in coal-fired boilers, combustion chambers and other energy systems requires accounting for the effects of inorganic deposits on bounding surfaces and of entrained particulates, such as pulverized coal, char and fly-ash. These effects can be predicted; however, the accuracy in predicting the radiative properties of entrained particles (ash) and deposit layers (slag) is limited by inaccurate knowledge of the physical/chemical properties of the materials over a range of material temperatures and radiative wavelengths that is representative of conditions in practical combustion systems. The objective of this project is to make laboratory measurements of the radiative properties of extracted ash deposit samples. During this quarter, technique validation measurements were performed on several test samples. Technique validation has been achieved for infrared opaque and semi-transparent materials that exhibit a high degree of specular reflection (i.e. having a negligible diffuse reflectance component). Validation has not been achieved for non-specular reflecting surfaces, but work is progressing on modifying the present system to accommodate these materials.

  14. Recovery of gold from gold slag by wood shaving fly ash.

    PubMed

    Aworn, Amphol; Thiravetyan, Paitip; Nakbanpote, Woranan

    2005-07-15

    Wood shaving fly ash was used as an alternative adsorbent for gold preconcentration from gold slag. The maximum gold adsorption capacity of wood shaving fly ash washed with tap water (WSFW) at 20, 30, 40, and 60 degrees C was 8.68, 7.79, 7.44, and 7.25 mg(Au)/g(adsorbent), respectively, while of activated carbon it was 76.78, 60.95, 56.13, and 51.90 mg(Au)/g(adsorbent), respectively. Deionized water at 100 degrees C could elute gold adsorbed onto WSFW to 71%. The effect of the increasing temperature of water, 30, 60, and 100 degrees C, implied that the adsorption mechanism was mainly physical adsorption. The negative values of enthalpy change (DeltaH) and free energy change (DeltaG) indicated an exothermic and spontaneous process, respectively. The positive values of entropy change (DeltaS) indicated increasing disorder of the system. The advantages of wood shaving fly ash are the purification of gold and the easier recycling of gold from the gold-adsorbed adsorbent. PMID:15925603

  15. Utilization of ferrochrome wastes such as ferrochrome ash and ferrochrome slag in concrete manufacturing.

    PubMed

    Acharya, Prasanna K; Patro, Sanjaya K

    2016-08-01

    Solid waste management is one of the subjects essentially addressing the current interest today. Due to the scarcity of land filling area, utilization of wastes in the construction sector has become an attractive proposition for disposal. Ferrochrome ash (FA) is a dust obtained as a waste material from the gas cleaning plant of Ferro alloy industries. It possesses the chemical requirements of granulated slag material used for the manufacture of Portland cement. Ferrochrome slag (FS) is another residue that is obtained as a solid waste by the smelting process during the production of stainless steel in Ferroalloy industries. FS possesses the required engineering properties of coarse aggregates. The possibility of using FA with lime for partial replacement of ordinary Portland cement (OPC) and FS for total replacement of natural coarse aggregates is explored in this research. The combined effect of FA with lime and FS-addition on the properties of concrete, such as workability, compressive strength, flexural strength, splitting tensile strength and sorptivity, were studied. Results of investigation revealed improvement in strength and durability properties of concrete on inclusion of FA and FS. Concrete mix containing 40% FA with 7% lime (replacing 47% OPC) and100% of FS (replacing 100% natural coarse aggregate) achieved the properties of normal concrete or even better properties at all ages. The results were confirmed by microscopic study such as X-ray diffraction and petrography examination. Environmental compatibility of concrete containing FA and FS was verified by the toxicity characteristic leaching procedure test. PMID:27357563

  16. THE IMPACT OF DISSOLVED SALTS ON PASTES CONTAINING FLY ASH, CEMENT AND SLAG

    SciTech Connect

    Harbour, J.; Edwards, T.; Williams, V.

    2009-09-21

    The degree of hydration of a mixture of cementitious materials (Class F fly ash, blast furnace slag and portland cement) in highly concentrated alkaline salt solutions is enhanced by the addition of aluminate to the salt solution. This increase in the degree of hydration, as monitored with isothermal calorimetry, leads to higher values of dynamic Young's modulus and compressive strength and lower values of total porosity. This enhancement in performance properties of these cementitious waste forms by increased hydration is beneficial to the retention of the radionuclides that are also present in the salt solution. The aluminate ions in the solution act first to retard the set time of the mix but then enhance the hydration reactions following the induction period. In fact, the aluminate ions increase the degree of hydration by {approx}35% over the degree of hydration for the same mix with a lower aluminate concentration. An increase in the blast furnace slag concentration and a decrease in the water to cementitious materials ratio produced mixes with higher values of Young's modulus and lower values of total porosity. Therefore, these operational factors can be fine tuned to enhance performance properties of cementitious waste form. Empirical models for Young modulus, heat of hydration and total porosity were developed to predict the values of these properties. These linear models used only statistically significant compositional and operational factors and provided insight into those factors that control these properties.

  17. Immobilisation of lead smelting slag within spent aluminate-fly ash based geopolymers.

    PubMed

    Ogundiran, M B; Nugteren, H W; Witkamp, G J

    2013-03-15

    This study presents the solidification/stabilisation and immobilisation of lead smelting slag (LSS) by its incorporation in coal fly ash - blast furnace slag based geopolymers. It also explores the use of a spent aluminium etching solution (AES) as geopolymer activator instead of the commonly used silicate solutions. The compressive strength of the geopolymers produced with the AES was lower than when applying a K-silicate solution as activator (100MPa versus 80MPa after 28 days). Compressive strength was not affected when up to 10% of the FA was replaced by LSS. NEN 12457-4, TCLP, SPLP and NEN 7375 leaching tests indicated that mobile Pb from LSS was highly immobilised. The diffusion leaching test NEN 7375 revealed exceeding of the Dutch Soil Quality Regulation threshold limits only for Se and Sb. On the condition that the remaining excess leaching can be reduced by further refinement of the mixture recipes, the proposed process will have the potential of producing waste-based construction materials that may be applied under controlled conditions in specific situations. PMID:23339881

  18. Frit screening for Rocky Flats ash and sand, slag, and crucible vitrification

    SciTech Connect

    Vienna, J.D.; Li, Hong; Darab, J.G.

    1997-06-01

    Pacific Northwest National Laboratory (PNNL) is developing vitrified waste forms for plutonium-bearing ash and plutonium-bearing sand, slag, and crucible (SS&C) materials from Rocky Flats. Waste forms are to meet product criteria (e.g., safeguard termination limits, storage criteria, and target plutonium loading) and processing constraints (e.g., upper temperature limits, processing time, and equipment compatibility). The target waste form for ash is an agglomerated product, while that for SS&C is a fully encapsulated product. Laboratory scoping studies were conducted on glass formulations from six different glass families: (1) antimony vanadium phosphate, (2) iron vanadium phosphate, (3) tin zinc phosphate, (4) soda-lime silicate, (5) alkali borosilicate, and (6) alkali borate. Glass families were selected due to viscosity behavior in the temperature range of interest (< 800C). Scoping study tests included gradient furnace tests to determine processing range and sintering temperature, thermogravimetric analysis to determine weight loss as a function of temperature, and crucible tests to determine frit compositions tolerance to variations in processing temperature, waste loading, and waste type. The primary screening criterion for the selection of frits for future studies was processing temperature below 400C to minimize the potential for foaming in ash caused by the release of gases (main source of gas is combustion of carbon species) and to minimize processing cycle times. Based on this criterion, glass formulations from the tin zinc phosphate and alkali borosilicate families were selected for future variability testing. Variability testing will include final product evaluation, glass system tolerance to waste loading and composition variation, and identification of parameters impacting time/temperature profiles. Variability testing results will give a final frit formulation for ash and SS&C, and identify key processing parameters. 12 refs., 13 figs., 9 tabs.

  19. Radioactivity of coals and ash and slag wastes at coal-fired thermal power plants

    NASA Astrophysics Data System (ADS)

    Krylov, D. A.; Sidorova, G. P.

    2013-04-01

    This paper presents an analysis of published data on the content of radioactive nuclides in coals originating from various coal deposits, and in ash and slag wastes produced at coal-fired thermal power plants, as well as in fly ash emitted from thermal power plants into the atmosphere. Problems related to the use of coals with an elevated content of natural radionuclides (NRNs) and methods of their solution implemented at the Urtuyskoe coalfield are dealt with. Data on the analysis of Transbaikal coals for the NRN content, as well as weighted mean content of uranium and thorium in coals from the Siberian Region, are given. In order to reduce irradiation of plant personnel and the population of the areas where coal producers and coal-fired thermal power plants are located, it is necessary to organize very careful control of the NRN content in both coals and products of their combustion that are released into the environment. To solve the problem related to the control of radioactivity, the centralized approach and creation of a proper normative base are needed. Experience gained in developing the Urtuyskoe coalfield shows that it is possible to create an efficient system of coal quality control with respect to the radiation hygiene factor and provide protection of the environment and health of the population.

  20. Hydrothermal solidification of municipal solid waste incineration bottom ash with slag addition.

    PubMed

    Jing, Zhenzi; Ran, Xianqiang; Jin, Fangming; Ishida, Emile H

    2010-01-01

    Hydrothermal solidification of municipal solid waste incineration (MSWI) bottom ash has been carried out under saturated steam pressure (1.56 MPa) at 200 degrees C for up to 24 h by mixing quartz, slaked lime and water-cooled blast furnace slag (WBFS). The strength enhancement for the WBFS addition was best. The strength development was shown to be due mainly to tobermorite formation, and the tobermorite formation densified matrix, thus promoting the strength development. WBFS seemed to have a higher reactivity than the quartz during the initial hydrothermal process, which provided more silica available to harden the solidified specimens. However, a longer curing time (24 h) was favorable to the quartz dissolution for tobermorite formation, which in turn, enhanced the strength for quartz addition. Curing time affected the crystal morphology evolution, and the stubby plate of tobermorite seemed to result in a high strength enhancement in this study. Laboratory leaching tests were conducted to determine the amount of heavy metals dissolved from the final solidified specimens, and the leaching results showed that after hydrothermal processing the heavy metals dissolved from the solidified specimens were reduced effectively. As such, the hydrothermal processing may have a high potential for recycling/reusing MSWI ash on a large scale. PMID:20385479

  1. Environmental assessment of no remedial action at the inactive uraniferous lignite ashing sites at Belfield and Bowman, North Dakota

    SciTech Connect

    1997-06-01

    The Belfield and Bowman sites were not included on the original congressional list of processing sites to be designated by the Secretary of Energy. Instead, the sites were nominated for designation by the Dakota Resource Council in a letter to the DOE (September 7, 1979). In a letter to the DOE (September 12, 1979), the state of North Dakota said that it did not believe the sites would qualify as processing sites under the Uranium Mill Tailings Radiation Control Act (UMTRCA) because the activities at the sites involved only the ashing of uraniferous lignite coal and the ash was shipped out of state for actual processing. Nevertheless, on October 11, 1979, the state of North Dakota agreed to the designation of the sites because they met the spirit of the law (reduce public exposure to radiation resulting from past uranium operations). Therefore, these sites were designated by the Secretary of Energy for remedial action. Because of the relatively low health impacts determined for these sites, they were ranked as low priority and scheduled to be included in the final group of sites to be remediated.

  2. Effect of biomass-sulfur interaction on ash composition and agglomeration for the co-combustion of high-sulfur lignite coals and olive cake in a circulating fluidized bed combustor.

    PubMed

    Varol, Murat; Atimtay, Aysel T

    2015-12-01

    This study aimed to investigate the effect of biomass-sulfur interaction on ash composition and agglomeration for the co-combustion of high-sulfur lignite coals and olive cake in a circulating fluidized bed combustor. The tests included co-combustion of 50-50% by wt. mixtures of Bursa-Orhaneli lignite+olive cake and Denizli-Kale lignite+olive cake, with and without limestone addition. Ash samples were subjected to XRF, XRD and SEM/EDS analyses. While MgO was high in the bottom ash for Bursa-Orhaneli lignite and olive cake mixture, Al2O3 was high for Denizli-Kale lignite and olive cake mixture. Due to high Al2O3 content, Muscovite was the dominant phase in the bottom ash of Denizli Kale. CaO in the bottom ash has increased for both fuel mixtures due to limestone addition. K was in Arcanite phase in the co-combustion test of Bursa/Orhaneli lignite and olive cake, however, it mostly appeared in Potassium Calcium Sulfate phase with limestone addition. PMID:26407346

  3. Hierarchical Order of Influence of Mix Variables Affecting Compressive Strength of Sustainable Concrete Containing Fly Ash, Copper Slag, Silica Fume, and Fibres

    PubMed Central

    Natarajan, Sakthieswaran; Karuppiah, Ganesan

    2014-01-01

    Experiments have been conducted to study the effect of addition of fly ash, copper slag, and steel and polypropylene fibres on compressive strength of concrete and to determine the hierarchical order of influence of the mix variables in affecting the strength using cluster analysis experimentally. While fly ash and copper slag are used for partial replacement of cement and fine aggregate, respectively, defined quantities of steel and polypropylene fibres were added to the mixes. It is found from the experimental study that, in general, irrespective of the presence or absence of fibres, (i) for a given copper slag-fine aggregate ratio, increase in fly ash-cement ratio the concrete strength decreases and with the increase in copper slag-sand ratio also the rate of strength decrease and (ii) for a given fly ash-cement ratio, increase in copper slag-fine aggregate ratio increases the strength of the concrete. From the cluster analysis, it is found that the quantities of coarse and fine aggregate present have high influence in affecting the strength. It is also observed that the quantities of fly ash and copper slag used as substitutes have equal “influence” in affecting the strength. Marginal effect of addition of fibres in the compression strength of concrete is also revealed by the cluster analysis. PMID:24707213

  4. Hierarchical order of influence of mix variables affecting compressive strength of sustainable concrete containing fly ash, copper slag, silica fume, and fibres.

    PubMed

    Natarajan, Sakthieswaran; Karuppiah, Ganesan

    2014-01-01

    Experiments have been conducted to study the effect of addition of fly ash, copper slag, and steel and polypropylene fibres on compressive strength of concrete and to determine the hierarchical order of influence of the mix variables in affecting the strength using cluster analysis experimentally. While fly ash and copper slag are used for partial replacement of cement and fine aggregate, respectively, defined quantities of steel and polypropylene fibres were added to the mixes. It is found from the experimental study that, in general, irrespective of the presence or absence of fibres, (i) for a given copper slag-fine aggregate ratio, increase in fly ash-cement ratio the concrete strength decreases and with the increase in copper slag-sand ratio also the rate of strength decrease and (ii) for a given fly ash-cement ratio, increase in copper slag-fine aggregate ratio increases the strength of the concrete. From the cluster analysis, it is found that the quantities of coarse and fine aggregate present have high influence in affecting the strength. It is also observed that the quantities of fly ash and copper slag used as substitutes have equal "influence" in affecting the strength. Marginal effect of addition of fibres in the compression strength of concrete is also revealed by the cluster analysis. PMID:24707213

  5. Characterisation of magnesium potassium phosphate cements blended with fly ash and ground granulated blast furnace slag

    SciTech Connect

    Gardner, Laura J.; Bernal, Susan A.; Walling, Samuel A.; Corkhill, Claire L.; Provis, John L.; Hyatt, Neil C.

    2015-08-15

    Magnesium potassium phosphate cements (MKPCs), blended with 50 wt.% fly ash (FA) or ground granulated blast furnace slag (GBFS) to reduce heat evolution, water demand and cost, were assessed using compressive strength, X-ray diffraction (XRD), scanning electron microscopy (SEM) and nuclear magnetic resonance (NMR) spectroscopy on {sup 25}Mg, {sup 27}Al, {sup 29}Si, {sup 31}P and {sup 39}K nuclei. We present the first definitive evidence that dissolution of the glassy aluminosilicate phases of both FA and GBFS occurred under the pH conditions of MKPC. In addition to the main binder phase, struvite-K, an amorphous orthophosphate phase was detected in FA/MKPC and GBFS/MKPC systems. It was postulated that an aluminium phosphate phase was formed, however, no significant Al–O–P interactions were identified. High-field NMR analysis of the GBFS/MKPC system indicated the potential formation of a potassium-aluminosilicate phase. This study demonstrates the need for further research on these binders, as both FA and GBFS are generally regarded as inert fillers within MKPC.

  6. High infrared radiance glass-ceramics obtained from fly ash and titanium slag.

    PubMed

    Wang, Shuming; Liang, Kaiming

    2007-11-01

    A new glass-ceramic was synthesized by crystal growth from a homogenous glass obtained by melting a mixture of fly ash collected from a power plant in Hebei province of China, titanium slag collected from a titanium factory in Sichuan province of China, and MgCO(3) as an additive. According to the measurement results of differential thermal analysis, a thermal treatment of nucleating at 850 degrees C for 2h and crystallizing at 985 degrees C for 1.5h was used to obtain the crystallized glass. X-ray diffraction and scanning electron microscopy measurements showed that the main crystalline phase of this material was iron-ion substituted cordierite, (Mg,Fe)(2)Al(4)Si(5)O(18), which is homogeneously dispersed within the parent glass matrix. The infrared radiance and thermal expansion coefficient of this material have been examined, and the results demonstrate that this glass-ceramic material has potential for application in a wide range of infrared heating and drying materials. PMID:17640707

  7. Baseline risk assessment of ground water contamination at the inactive uriniferous lignite ashing site near Belfield, North Dakota

    SciTech Connect

    1994-08-01

    This Baseline Risk Assessment of Ground Water Contamination at the Inactive Uraniferous Lignite Ashing Site Near Belfield, North Dakota, evaluates potential impacts to public health or the environment resulting from ground water contamination at the site where coal containing uranium was burned to produce uranium. The US Department of Energy`s Uranium Mill Tailings Remedial Action (UMTRA) Project is evaluating plans to remedy soil and ground water contamination at the site. Phase I of the UMTRA Project consists of determining the extent of soil contamination. Phase II of the UMTRA Project consists of evaluating ground water contamination. Under Phase II, results of this risk assessment will help determine what remedial actions may be necessary for contaminated ground water at the site. This risk assessment evaluates the potential risks to human health and the environment resulting from exposure to contaminated ground water as it relates to historic processing activities at the site. Potential risk is quantified for constituents introduced from the processing activities, and not for those constituents naturally occurring in water quality in the site vicinity. Background ground water quality has the potential to cause adverse health effects from exposure through drinking. Any risks associated with contaminants attributable to site activities are incremental to these risks from background ground water quality. This incremental risk from site-related contaminants is quantified in this risk assessment. The baseline risk from background water quality is incorporated only into the assessment of potential chemical interactions and the definition of the overall site condition.

  8. Effect of water quenching and SiO2 addition during vitrification of fly ash Part 1: on the crystalline characteristics of slags.

    PubMed

    Kuo, Yi-Ming; Wang, Jian-Wen; Wang, Chih-Ta; Tsai, Cheng-Hsien

    2008-04-15

    The objective of this study is to investigate how cooling rate and basicity in a vitrification process govern the crystalline characteristics of slags. In this experiment, the incineration fly ash mixtures with various SiO2 addition ratios were vitrified at 1450 degrees C and cooled down separately by air or water. Different thermal analysis, scanning electron microscopy and X-ray diffraction analysis with an internal standard addition were applied to investigate the crystalline characteristics of slags. The microanalytical mapping images showed that water quenching and the addition of SiO2, both enhanced the glassy amorphous phase to distribute more uniformly in slags. Addition of SiO2 would lower the melting temperature of fly ash mixtures and retard the formation of crystalline phases in slags. When the basicity (mass ratio of CaO to SiO2 before vitrification) was >0.990, the profiles of crystalline phases in slags with equal basicity were similar no matter how they were cooled. However, when the basicity <0.674, water quenching greatly enhanced the formation of the glassy amorphous phase in slags. For air cooled slags, an even lower basicity (<0.511) is required to vitrify fly ash well. PMID:17766040

  9. Investigation on the application of steel slag-fly ash-phosphogypsum solidified material as road base material.

    PubMed

    Shen, Weiguo; Zhou, Mingkai; Ma, Wei; Hu, Jinqiang; Cai, Zhi

    2009-05-15

    The aim of the present work is to prepare a new type of steel slag-fly ash-phosphogypsum solidified material totally composed with solid wastes to be utilized as road base material. The mix formula of this material was optimized, the solidified material with optimal mix formula (fly ash/steel slag=1:1, phosphogypsum dosage=2.5%) results in highest strength. The strength development, resilience modulus and splitting strength of this material were studied comparing with some typical road base materials, the 28- and 360-day strength of this material can reach 8MPa and 12MPa, respectively, its resilience modulus reaches 1987MPa and splitting strength reaches 0.82MPa, it has higher early strength than lime-fly ash and lime-soil road base material, its long-term strength is much higher than cement stabilized granular materials, the solidified material has best water stability among those road base materials, it can be engineered as road base material with competitive properties. The strength formation mechanism of this solidified material is discussed also. PMID:18801617

  10. Influence of a Modification of the Petcoke/Coal Ratio on the Leachability of Fly Ash and Slag Produced from a Large PCC Power Plant

    SciTech Connect

    Izquierdo,M.; Font, O.; Moreno, N.; Querol, X.; Huggins, F.; Alvarez, E.; Diez, S.; Otero, P.; Ballesteros, J.; Gimenez, A.

    2007-01-01

    Co-firing of coal with inexpensive secondary fuels such as petroleum coke is expected to increase in the near future in the EU given that it may provide certain economic and environmental benefits with respect to coal combustion. However, changes in the feed fuel composition of power plants may modify the bulk content and the speciation of a number of elements in fly ash and slag. Consequently, leachability of these byproducts also can be modified. This study is focused on identifying the changes in the environmental quality of co-fired fly ash and slag induced by a modification of the petcoke/coal ratio. Petcoke was found to increase the leachable content of V and Mo and to enhance the mobility of S and As. However, with the exception of these elements, the addition of this secondary fuel did not drastically modify the bulk composition or the overall leachability of the resulting fly ash and slag.

  11. Chemical speciation, mobility and phyto-accessibility of heavy metals in fly ash and slag from combustion of pelletized municipal sewage sludge.

    PubMed

    Xiao, Zhihua; Yuan, Xingzhong; Li, Hui; Jiang, Longbo; Leng, Lijian; Chen, Xiaohong; Zeng, Guangming; Li, Fei; Cao, Liang

    2015-12-01

    Combustion of pelletized municipal sewage sludge (MSS) can generate pestilent byproducts: fly ash and slag. Comparisons of heavy metal sequential extraction results among MSS, fly ash and slag showed that after combustion, the bioavailable heavy metal fractions (acid soluble/exchangeable, reducible and oxidizable fractions) were mostly transformed into the very stable heavy metal fractions (residual fractions). On the other hand, the results of toxicity characteristic leaching procedure (TCLP), diethylenetriamine pentaacetic acid and HCl extraction (phyto-accessibility assessment) demonstrated that the mobility and toxicity of heavy metals were greatly reduced. The direct and long-term bioavailability and eco-toxicity of heavy metals in fly ash and slag were relieved, which implied that combustion of pelletized MSS could be a promising and completely safe disposal technology for MSS treatment. PMID:26254077

  12. Economic evaluation of losses to electric power utilities caused by ash fouling. Final technical report, November 1, 1979-April 30, 1980

    SciTech Connect

    Burkhardt, F.R.; Persnger, M.M.

    1980-01-01

    Problems with convection ash fouling and wall slagging were considerable during our study. The Dakota lignites posed the greatest problems, particularly with fouling. The subbituminous coals had considerable problems, related mostly with wall slagging. The Texas lignites had few problems, and those were only associated with wall slagging. The generation losses were as follows: The Dakota lignite burning stations averaged an overall availability of 87.13%. Convection fouling outages were responsible for 57.75% of this outage time for a decrease in availability of 7.43%. Fouling was responsible for curtailment losses of 317,649 Mwh or 8.25% of the remaining available generation. Slagging was responsible for losses of 2732 megawatt hours or .07% of the remaining available generation. Total ash related losses amounted to 16.08% of the total available generation. The subbituminous burning stations averaged an overall availability of 78.36%. Total ash related losses amounted to 1.54% of the total available generation. The Texas lignite burning stations averaged an overall availability of 80.63%. No ash related outage losses occurred. Slagging curtailments accounted 0.08% of the total available generation. Costs due to ash fouling and slagging related curtailments are a tremendous sum. Seven power stations were studied for a six month period to assess costs. The total cost directly attributable to ash slagging and fouling condition was $20,638,113. Recommendations for reducing the problems involve soot blowers, control of furnace gas exit temperature, water blowers and more conservative boiler design.

  13. Survey and conceptual flow sheets for coal conversion plant handling-preparation and ash/slag removal operations

    SciTech Connect

    Zapp, F.C.; Thomas, O.W.; Silverman, M.D.; Dyslin, D.A.; Holmes, J.M.

    1980-03-01

    This study was undertaken at the request of the Fossil Fuel Processing Division of the Department of Energy. The report includes a compilation of conceptual flow sheets, including major equipment lists, and the results of an availability survey of potential suppliers of equipment associated with the coal and ash/slag operations that will be required by future large coal conversion plant complexes. Conversion plant flow sheet operations and related equipment requirements were based on two representative bituminous coals - Pittsburgh and Kentucky No. 9 - and on nine coal conversion processes. It appears that almost all coal handling and preparation and ash/slag removal equipment covered by this survey, with the exception of some coal comminution equipment, either is on hand or can readily be fabricated to meet coal conversion plant capacity requirements of up to 50,000 short tons per day. Equipment capable of handling even larger capacities can be developed. This approach appears to be unjustified, however, because in many cases a reasonable or optimum number of trains of equipment must be considered when designing a conversion plant complex. The actual number of trains of equipment selected will be influenced by the total requied capacity of the complex, the minimum on-line capacity that can be tolerated in case of equipment failure, reliability of specific equipment types, and the number of reactors and related feed injection stations needed for the specific conversion process.

  14. The role of open and closed curing conditions on the leaching properties of fly ash-slag-based geopolymers.

    PubMed

    Izquierdo, Maria; Querol, Xavier; Phillipart, Charles; Antenucci, Diano; Towler, Mark

    2010-04-15

    This study deals with the synthesis of geopolymers from co-fired fly ash and blast furnace slags. Geopolymer bodies were simultaneously synthesized in open and closed curing conditions in order to elucidate the role of this parameter on their resultant properties. Open curing conditions produce solid bodies characterized by high porosity, low compressive strength and exacerbated leaching of certain oxyanionic metalloids. By contrast, protected curing promotes the binder development, giving rise to higher strength and less porous systems. This imposes physical restrictions to leaching which decreases and/or retards releases of oxyanionic metalloids in comparison to open curing conditions. Fly ash-slag-based geopolymers may immobilize a number of trace pollutants such as Be, Bi, Cd, Co, Cr, Cu, Nb, Ni, Pb, REE, Sn, Th, U, Y and Zr, regardless of the curing conditions. Due to geopolymers displaying weak assimilation capacity for oxyanionic species, their successful regarding oxyanionic retention is strongly dependent on porosity and therefore on curing conditions applied. PMID:20005626

  15. Characteristics of slag, fly ash and deposited particles during melting of dewatered sewage sludge in a pilot plant.

    PubMed

    Kanchanapiya, Premrudee; Sakano, Takeo; Kanaoka, Chikao; Mikuni, Tokuyoshi; Ninomiya, Yoshihiko; Zhang, Lian; Masui, Megumi; Masami, Furuuchi

    2006-04-01

    This study examines slag, fly ash, and deposited particles during melting of dewatered sewage sludge in a pilot plant. In addition, the chemical composition of particles in flue gas was simulated using a thermodynamics program, namely FACTSage 5.2. The results showed that the main components of slag were Al, Fe, Ca, P and Si; the minor components were Na, K, Mg, Cu, and Zn. The main chemical compound of slag was Ca4(Mg,Fe)5(PO4)6. For fly ash particles, heavy metals with the highest concentrations were in the order of Zn and As, Pb, Cu, and Cd, respectively. For non-heavy metals, Al, Fe and P were also found in significant amounts. The majority of deposited particles were composed of elements of Zn, P, S, Na, Fe, Al, Si, and Ca and such chemical compounds as Zn3(PO4)2, AlPO4, FePO4 and Fe(OH)3 while the minority consisted of elements of As, Cu, and Pb. Moreover, the compositions of deposited particles in each chamber differed due to different flue gas temperatures inside. In the secondary chamber at 760 degrees C, the amounts of Fe and Al were higher than Zn, whereas, in the other chambers (600-400 degrees C), the amount of Zn was higher. In other words, at the lower temperature the deposition of Zn was higher than the deposition of Fe and Al. In the water cooling section, volatile elements (i.e. Zn, As, Cu, Pb) were found in the highest concentrations due to a big difference in temperature between the wall surface and flue gas. From the simulation results, most of the elements in the gas phase were found to be chloride compounds, whereas those in the solid phase were in the form of oxide, sulfate, and phosphate compounds. PMID:16198048

  16. Effect of fuel quality on slagging behavior in a cyclone-fired boiler

    SciTech Connect

    Katrinak, K.; Laumb, J.; Peterson, W.; Schwalbe, R.

    1998-12-31

    Relationships between the occurrence of poor slag flow episodes at a cyclone-fired boiler, coal mineral content, heating value, and other fuel quality parameters have been investigated. In addition, optimization of boiler operating conditions to match coal quality is the major emphasis of current activities. The boiler fires North Dakota lignite, a highly variable fuel, and experiences intermittent cyclone slagging problems related to coal quality. Cyclone slagging episodes were found to occur when the heating value of the fuel was less than 6600 Btu/lb and the T250 was greater than 2250 F. Higher-Btu coals burn hotter and appear to be able to handle higher T250 values without slagging. Other fuel quality parameters related to cyclone slag flow behavior include high silicon and aluminum concentrations and high concentrations of the silicon- and aluminum-rich clay minerals illite and montmorillonite. These minerals are thought to contribute to cyclone slagging episodes by reducing the ability of the slag to incorporate calcium, thus leading to increased slag viscosity. To improve slag flow behavior, operating conditions have been modified to maintain high temperatures in the cyclones. Changes include increasing coal drying temperature and balancing the air/fuel ratio. T250 can be readily calculated from coal ash composition. Clays and other minerals can be identified in individual coal particles using automated scanning electron microscopy with energy-dispersive X-ray spectrometry. Use of these analytical techniques can enable potential cyclone slagging problems to be predicted in advance.

  17. Recycling municipal incinerator fly- and scrubber-ash into fused slag for the substantial replacement of cement in cement-mortars.

    PubMed

    Lee, Tzen-Chin; Rao, Ming-Kang

    2009-06-01

    Fly- and scrubber-ash (weight ratio of approximately 1:3) from municipal solid waste incinerators (MSWI) are a major land-fill disposal problem due to their leaching of heavy metals. We uniformly mixed both types of ash with optimal amounts of waste glass frit, which was then melted into a glassy slag. The glassy slag was then pulverized to a particle size smaller than 38microm for use as a cement substitute (20-40% of total cement) and blended with sand and cement to produce slag-blended cement-mortar (SCM) specimens. The toxicity characteristics of the leaching procedure tests on the pulverized slag samples revealed that the amount of leached heavy metals was far below regulatory thresholds. The compressive strength of the 28-day cured SCM specimens was comparable to that of ordinary Portland cement mortars, while the compressive strength of specimens cured for 60 or 90 days were 3-11% greater. The observed enhanced strength is achieved by Pozzolanic reaction. Preliminary evaluation shows that the combination of MSWI fly- and scrubber-ash with waste glass yields a cost effective and environmentally friendly cement replacement in cement-mortars. PMID:19216067

  18. Assessment of Pb-slag, MSWI bottom ash and boiler and fly ash for using as a fine aggregate in cement mortar.

    PubMed

    Saikia, Nabajyoti; Cornelis, Geert; Mertens, Gilles; Elsen, Jan; Van Balen, Koenraad; Van Gerven, Tom; Vandecasteele, Carlo

    2008-06-15

    Three types of wastes, metallurgical slag from Pb production (SLG), the sand-sized (0.1-2 mm) fraction of MSWI bottom ash from a grate furnace (SF), and boiler and fly ash from a fluidised bed incinerator (BFA), were characterized and used to replace the fine aggregate during preparation of cement mortar. The chemical and mineralogical behaviour of these wastes along with the reactivities of the wastes with lime and the hydration behaviour of ordinary Portland cement paste with and without these wastes added were evaluated by various chemical and instrumental techniques. The compressive strengths of the cement mortars containing waste as a partial substitution of fine aggregates were also assessed. Finally, leaching studies of the wastes and waste containing cement mortars were conducted. SLG addition does not show any adverse affect during the hydration of cement, or on the compressive strengths behaviours of mortars. Formation of expansive products like ettringite, aluminium hydroxide and H2 gas due to the reaction of some constituents of BFA and SF with alkali creates some cracks in the paste as well as in the cement mortars, which lower the compressive strength of the cement mortars. However, utilization of all materials in cement-based application significantly improves the leaching behaviour of the majority of the toxic elements compared to the waste as such. PMID:18068299

  19. Fourth international conference on fly ash, silica fume, slag, and natural pozzolans in concrete: Supplemental proceedings

    SciTech Connect

    Berry, E.E.; Hemmings, R.T.; Zhang, M.H. ); Malhotra, V.M. )

    1992-03-01

    This report consists of four papers presented at a special session on high volume fly ash (HVFA) concrete. These four papers summarize an EPRI research project currently in progress that is investigating HVFA concretes. This objective of this research is to commercialize the HVFA concrete technology through: (1) an extensive measurement of basic engineering and durability properties; (2) an examination of the binder microstructure and cementation hydration reactions; and (3) technology transfer to industry and the construction community. Overall the data from the project that are summarized in these papers, show that commercial quality structural grade concrete (up to 50 MPa compressive strength at 90 days) can be made from a wide range of fly ashes and cements available throughout the USA. It has been shown in this project that fly ash is a reactive participant with the Portland cement in the cementing process, and also serves as a microaggregate in a multiphase composite binder formed during curing. The properties of the binder were found to significantly influence strength development, elastic modulus, and the stress-strain behavior of HVFA concrete. Overall, the data presented show that regardless of the type of fly ash (from the nine US ashes evaluated) and the two cements used, that air-entrained HVFA concrete exhibits excellent durability in all respects except under application of deicing salts where some surface scaling has been observed in the laboratory.

  20. Coal fly ash-slag-based geopolymers: microstructure and metal leaching.

    PubMed

    Izquierdo, Maria; Querol, Xavier; Davidovits, Joseph; Antenucci, Diano; Nugteren, Henk; Fernández-Pereira, Constantino

    2009-07-15

    This study deals with the use of fly ash as a starting material for geopolymeric matrices. The leachable concentrations of geopolymers were compared with those of the starting fly ash to evaluate the retention of potentially harmful elements within the geopolymer matrix. Geopolymer matrices give rise to a leaching scenario characterised by a highly alkaline environment, which inhibits the leaching of heavy metals but may enhance the mobilization of certain oxyanionic species. Thus, fly ash-based geopolymers were found to immobilize a number of trace pollutants such as Be, Bi, Cd, Co, Cr, Cu, Nb, Ni, Pb, Sn, Th, U, Y, Zr and rare earth elements. However, the leachable levels of elements occurring in their oxyanionic form such as As, B, Mo, Se, V and W were increased after geopolymerization. This suggests that an optimal dosage, synthesis and curing conditions are essential in order to obtain a long-term stable final product that ensures an efficient physical encapsulation. PMID:19118943

  1. Influence of a modification of the petcoke/coal ratio on the leachability of fly ash and slag produced from a large PCC power plant

    SciTech Connect

    Maria Izquierdo; Oriol Font; Natalia Moreno

    2007-08-01

    Co-firing of coal with inexpensive secondary fuels such as petroleum coke is expected to increase in the near future in the EU given that it may provide certain economic and environmental benefits with respect to coal combustion. However, changes in the feed fuel composition of power plants may modify the bulk content and the speciation of a number of elements in fly ash and slag. Consequently, leachability of these byproducts also can be modified. This study is focused on identifying the changes in the environmental quality of co-fired fly ash and slag induced by a modification of the petcoke/coal ratio. Petcoke was found to increase the leachable content of V and Mo and to enhance the mobility of S and As. However, with the exception of these elements, the addition of this secondary fuel did not drastically modify the bulk composition or the overall leachability of the resulting fly ash and slag. 30 refs., 3 figs., 2 tabs.

  2. Pelletizing lignite

    DOEpatents

    Goksel, Mehmet A.

    1983-11-01

    Lignite is formed into high strength pellets having a calorific value of at least 9,500 Btu/lb by blending a sufficient amount of an aqueous base bituminous emulsion with finely-divided raw lignite containing its inherent moisture to form a moistened green mixture containing at least 3 weight % of the bituminous material, based on the total dry weight of the solids, pelletizing the green mixture into discrete green pellets of a predetermined average diameter and drying the green pellets to a predetermined moisture content, preferrably no less than about 5 weight %. Lignite char and mixture of raw lignite and lignite char can be formed into high strength pellets in the same general manner.

  3. Leaching of polycyclic aromatic hydrocarbons from power plant lignite ash--influence of parameters important for environmental pollution.

    PubMed

    Pergal, Miodrag M; Relić, Dubravka; Tešić, Zivoslav Lj; Popović, Aleksandar R

    2014-03-01

    Nikola Tesla B power plant (TENT B), located at the Sava River, in Obrenovac, 50 km west from the Serbian's capital, Belgrade, is the second largest coal-fired power plant in the country, consisting of two blocks, each of 620 MW capacity. In order to investigate the threat polycyclic aromatic hydrocarbons (PAHs) from deposited coal ash, obtained by coal combustion in this power plant, can represent for the surrounding environment, samples of coal ash were submitted to extraction with river water used for transport of coal ash to the dump, as well as with water of different ionic strength and acidity. It was found that, out of 16 EPA priority PAHs, only naphthalene, acenaphthylene, fluorene, phenantrene, fluoranthene, and pyrene were found in measurable concentrations in the different extracts. Their combined concentration was around 0.1 μg/L, so they do not, in terms of leached concentrations, represent serious danger for the surrounding environment. In all cases of established (and leached) PAH compounds, changes of ionic strength, acidity, or the presence of organic compounds in river water may to some extent influence the leached concentrations. However, under the examined conditions, similar to those present in the environment, leached concentrations were not more than 50 % greater than the concentrations leached by distilled water. Therefore, water desorption is likely the most important mechanism responsible for leaching of PAH compounds from filter coal ash. PMID:24243163

  4. Mineral matter identification of some Turkish lignites

    SciTech Connect

    Yaman, S.; Taptik, Y.; Kuecuekbayrak, S.; Kadioglu, E.

    1995-01-01

    Samples of 15 Turkish lignites were oxidized by performic acid. Their mineral matter was isolated without any important chemical decomposition. The X-ray diffraction method was employed to determine the mineral species in the isolated mineral matter and in the ashes of the lignite samples. The results were compared and discussed.

  5. The evolution of strength and crystalline phases for alkali-activated ground blast furnace slag and fly ash-based geopolymers

    SciTech Connect

    Oh, Jae Eun; Monteiro, Paulo J.M.; Jun, Ssang Sun; Choi, Sejin; Clark, Simon M.

    2010-02-15

    The increase in strength and evolution of crystalline phases in inorganic polymer cement, made by the alkali activation of slag, Class C and Class F fly ashes, was followed using compressive strength test and synchrotron X-ray diffraction. In order to increase the crystallinity of the product the reactions were carried out at 80 deg. C. We found that hydrotalcite formed in both the alkali-activated slag cements and the fly ash-based geopolymers. Hydroxycancrinite, one member of the ABC-6 family of zeolites, was found only in the fly ash geopolymers. Assuming that the predominantly amorphous geopolymer formed under ambient conditions relates to the crystalline phases found when the mixture is cured at high temperature, we propose that the structure of this zeolitic precursor formed in Na-based high alkaline environment can be regarded as a disordered form of the basic building unit of the ABC-6 group of zeolites which includes poly-types such as hydroxycancrinite, hydroxysodalite and chabazite-Na.

  6. Properties of mortars made by uncalcined FGD gypsum-fly ash-ground granulated blast furnace slag composite binder.

    PubMed

    Zhong, Shiyun; Ni, Kun; Li, Jinmei

    2012-07-01

    A series of novel mortars were developed from composite binder of uncalcined FGD gypsum, fly ash (FA) and ground granulated blast furnace slag (GGBFS) for the good utilization of flue gas desulphurization (FGD) gypsum. At a fixed ratio (20%) of GGBFS to the composite binder, keeping consistency of the mortar between 9.5 and 10.0 cm, the properties of the composite mortar were studied. The results show that higher water/binder (W/B) is required to keep the consistency when increasing the percentage of FGD gypsum. No obvious influences of the W/B and content of FGD gypsum on the bleeding of paste were observed which keeps lower than 2% under all experimental conditions tried. The highest compressive and flexural strengths (ratio is 20% FGD gypsum, 20% GGBFS and 60% FA) are 22.6 and 4.3 MPa at 28 days, respectively. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) results indicate that massive ettringite crystals and C-S-H gels exist in the hydration products. At 90 days the mortars with FGD gypsum is dramatically smaller drying shrinkage (563-938 micro strain) than that without FGD gypsum (about 2250 micro strain). The release of the SO(4)(2-) from the mortar was analyzed, indicating that the dissolution of sulfate increases with FGD gypsum. The concentration of SO(4)(2-) releasing from the mortar with 10% FGD gypsum is almost equal to that obtained from the mortar without FGD gypsum. The release of SO(4)(2-) from the mortar with 20% FGD gypsum is 9200 mg·m(-2), which is lower than that from the mortar with 95% cement clinker and 5% FGD gypsum. PMID:22440404

  7. Properties of mortars made by uncalcined FGD gypsum-fly ash-ground granulated blast furnace slag composite binder

    SciTech Connect

    Zhong Shiyun; Ni Kun; Li Jinmei

    2012-07-15

    Highlights: Black-Right-Pointing-Pointer The mortar with uncalcined FGD gypsum has suitable workability. Black-Right-Pointing-Pointer The strength of mortar with uncalcined FGD gypsum is higher than that of mortar without uncalcined FGD gypsum. Black-Right-Pointing-Pointer The dry shrinkage of mortar with uncalcined FGD gypsum is lower than that of mortar without uncalcined FGD gypsum. Black-Right-Pointing-Pointer The leaching of sulfate ion of mortar is studied. - Abstract: A series of novel mortars were developed from composite binder of uncalcined FGD gypsum, fly ash (FA) and ground granulated blast furnace slag (GGBFS) for the good utilization of flue gas desulphurization (FGD) gypsum. At a fixed ratio (20%) of GGBFS to the composite binder, keeping consistency of the mortar between 9.5 and 10.0 cm, the properties of the composite mortar were studied. The results show that higher water/binder (W/B) is required to keep the consistency when increasing the percentage of FGD gypsum. No obvious influences of the W/B and content of FGD gypsum on the bleeding of paste were observed which keeps lower than 2% under all experimental conditions tried. The highest compressive and flexural strengths (ratio is 20% FGD gypsum, 20% GGBFS and 60% FA) are 22.6 and 4.3 MPa at 28 days, respectively. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) results indicate that massive ettringite crystals and C-S-H gels exist in the hydration products. At 90 days the mortars with FGD gypsum is dramatically smaller drying shrinkage (563-938 micro strain) than that without FGD gypsum (about 2250 micro strain). The release of the SO{sub 4}{sup 2-} from the mortar was analyzed, indicating that the dissolution of sulfate increases with FGD gypsum. The concentration of SO{sub 4}{sup 2-} releasing from the mortar with 10% FGD gypsum is almost equal to that obtained from the mortar without FGD gypsum. The release of SO{sub 4}{sup 2-} from the mortar with 20% FGD gypsum is 9200 mg

  8. Characterisation and treatment of roads covered with zinc ashes, muffle furnace fragments and lead slags from former non-ferrous metal industries in Belgium.

    PubMed

    Vandecasteele, C; Van den Broeck, K; Van Gerven, T; Dutré, V; Seuntjens, P; Berghmans, P; Cornelis, C; Nouwen, J

    2002-08-01

    Zinc ashes, muffle furnace fragments and lead slags from non-ferrous industries were applied to pave roads in the North of Belgium. From an inventory it appeared that there are at least 490 km of such roads. In our survey the materials on these roads were characterised. The total metal concentration, the availability and the leaching as a function of time were determined. It appeared that these materials contain high concentrations of heavy metals, some of which are readily available. The high leaching of some metals makes them as such unsuitable as secondary construction material. Methods for the application of these materials for road construction were examined where the materials replaced part of the sand and gravel fraction in lean concrete and in bituminous mixtures, or where they replaced the sand in sand-cement mixtures, all these to be used for road foundations, cycle tracks, etc. When lead slags were applied in lean concrete, a material was obtained complying with the standards for secondary construction materials and with sufficient compressive strength for road foundations. When zinc ashes or muffle fragments were used to replace sand in sand-cement mixtures, again a suitable construction material was obtained. The other combinations tried out were rather unsuccessful, because of high metal leaching and/or poor compressive strength. PMID:12363097

  9. Secondary superheater slagging reduction

    SciTech Connect

    Larose, J.A. ); Benson, R.C. )

    1992-01-01

    Utility boilers can be modified to reduce excessive slagging on the secondary superheater lower leading edges. Reduction of the high slagging accumulation rates will increase the pendant heat absorption and reduce the required superheater cleaning and slag removal. The cause of te slagging and appropriate boiler modifications are determined with numerical modeling. Results from two utility boiler analyses showed that regions of high gas and particle temperatures and flow rates exist near the superheater lower surfaces and are the probable cause of the rapid slagging. Design modifications which redistribute the flow and reduce the temperature entering the superheater reduce the impaction of molten ash on the pendant surface; this lowers the slag accumulation rate which allows the boiler to operate longer without cleaning and at a higher capacity. This paper shows the potential improvements in the secondary superheater inlet conditions by modifying the boiler.

  10. Firing system modification to alter ash properties for reduction of deposition and slagging under low NOx firing conditions

    SciTech Connect

    Hart, D.; Lewis, R.; Tobiasz, R.; Chen, W.

    1998-07-01

    The composition and properties of ash formed during coal firing have a major impact on boiler performance. Higher ash content in the coal can mean higher costs associated with coal handling, transportation, ash removal and ash disposal along with higher costs due to the increased ash content's deleterious effects on pulverizing, combustion and heat transfer. ABB C-E Services, Inc. has conducted research what might be done to minimize the adverse effects of ash on boiler performance for many years. Recently, ABB C-E Services has studied the effects of firing system modifications on ash composition and properties and the effect these firing system modifications have on overall furnace performance. The subject of this paper is the impact of the installation of the CFS{trademark} yaw angles were varied and particle samples were collected at the waterwalls for the different yaw angles tested. These ash samples were analyzed for ash composition. The results showed that with a larger CFS{trademark} yaw angle (the air stream directed more towards the boiler walls) the base/acid ratio, iron content and sulfur content of the particle samples collected at the waterwall were reduced. This effect is due to several contributing factors: (1) an oxidizing environment produced by injecting more air toward the walls; and (2) an aerodynamic change which impacts the particle combustion time/temperature history.

  11. Evaluation of lignite combustion residues as cement additives

    SciTech Connect

    Demirbas, A.; Aslan, A.

    1999-07-01

    In this study the physical and chemical properties of lignite fly ashes obtained from electrostatic precipitator and cyclone, lignite bottom ash, cement + lignite ash mixtures, and their effects on mechanical properties of concrete were investigated. The ashes were classified into two general types based on total silica, alumina, and iron-III oxide: class A and class B. When 25% of the cement was replaced by class A lignite bottom ash (the combined three oxide contents were 30.2%), the 28-day compressive strength increased by 18.9% compared to the control mix, and when 25% of the cement was replaced by class B lignite ash (the combined three oxide contents were 78.1%), the compressive strength decreased by 3.5% compared to the control mix. The results obtained were compared with the Turkish Standards and, in general, were found to be within the limits. As a result, the lignite fly ash and bottom ash samples may be used as cementitious materials.

  12. Multiple-use marketing of lignite

    SciTech Connect

    Knudson, C.L.

    1993-09-01

    Marketing of lignite faces difficulties due to moisture and sulfur contents, as well as the sodium content, of the ash. The purpose of this study is to determine the economic viability of multiple-use marketing of lignite as a method to increase the use of North Dakota lignite by recapturing lost niche markets. Multiple-use marketing means using lignite and sulfur-capturing additives to clean agricultural wastewater followed by either direct steam and power generation or briquetting to produce a higher-Btu compliance fuel. Cooperative ownership of the resulting business by a coal company and an agriculture processing company helps ensure that lignite remains the coal of choice, especially when the ``good`` attributes of lignites are maximized, while the agricultural company obtains cleaner wastewater and a long-term supply of coal at a set price. The economic viabilities of the following scenarios were investigated: (1) Agriprocessing wastewater treatment using lignite and an additive followed by (2) the production of compliance fuel for resale or on-site cogeneration of steam and electricity. Laboratory tests were performed utilizing potato-processing plant wastewater with lignite and lime sludge.

  13. Alkali Activated Systems: Understanding the Influence of Curing Conditions and Activator Type/Chemistry on the Mechanical Strength and Chemical Structure of Fly Ash/Slag Systems

    NASA Astrophysics Data System (ADS)

    Chowdhury, Ussala

    The alkali activation of aluminosilicate materials as binder systems derived from industrial byproducts have been extensively studied due to the advantages they offer in terms enhanced material properties, while increasing sustainability by the reuse of industrial waste and byproducts and reducing the adverse impacts of OPC production. Fly ash and ground granulated blast furnace slag are commonly used for their content of soluble silica and aluminate species that can undergo dissolution, polymerization with the alkali, condensation on particle surfaces and solidification. The following topics are the focus of this thesis: (i) the use of microwave assisted thermal processing, in addition to heat-curing as a means of alkali activation and (ii) the relative effects of alkali cations (K or Na) in the activator (powder activators) on the mechanical properties and chemical structure of these systems. Unsuitable curing conditions instigate carbonation, which in turn lowers the pH of the system causing significant reductions in the rate of fly ash activation and mechanical strength development. This study explores the effects of sealing the samples during the curing process, which effectively traps the free water in the system, and allows for increased aluminosilicate activation. The use of microwave-curing in lieu of thermal-curing is also studied in order to reduce energy consumption and for its ability to provide fast volumetric heating. Potassium-based powder activators dry blended into the slag binder system is shown to be effective in obtaining very high compressive strengths under moist curing conditions (greater than 70 MPa), whereas sodium-based powder activation is much weaker (around 25 MPa). Compressive strength decreases when fly ash is introduced into the system. Isothermal calorimetry is used to evaluate the early hydration process, and to understand the reaction kinetics of the alkali powder activated systems. A qualitative evidence of the alkali

  14. Disposal of Ash and Slag Waste of the Berezovsk State Regional Power Plant in the Berezovskii-1 Mined-Out Space: A Promising Direction of Environmental Protection in the Region

    SciTech Connect

    Ozerskii, A. Yu.; Ozerskii, D. A.

    2003-07-15

    The results of a study of the mineral, chemical, and radionuclide compositions of ash and slag waste of the Berezovsk state regional power plant (BGRES-1) and the capping of the Berezovskii-1 coal mine suggest disposal of the waste into the mined-out space. The ash and slag waste and the capping are composed of low-toxicity materials and do not endanger the environment, which makes it possible to use the suggested technology. The use of the waste for reclamation of refuse soils should have a positive ecological effect due to chemical melioration, strengthening, and lower settlement of the refuse soils and compensation of the rock mass deficit in the mined-out space.

  15. An Empirical Viscosity Model for Coal Slags

    SciTech Connect

    Matyas, Josef; Cooley, Scott K.; Sundaram, S. K.; Rodriguez, Carmen P.; Edmondson, Autumn B.; Arrigoni, Benjamin M.

    2008-10-25

    Slags of low viscosity readily penetrate the refractory lining in slagging gasifiers, causing rapid and severe corrosion called spalling. In addition, a low-viscosity slag that flows down the gasifier wall forms a relatively thin layer of slag on the refractory surface, allowing the corrosive gases in the gasifier to participate in the chemical reactions between the refractory and the slag. In contrast, a slag viscosity of <25 Pa•s at 1400°C is necessary to minimize the possibility of plugging the slag tap. There is a need to predict and optimize slag viscosity so slagging gasifiers can operate continuously at temperatures ranging from 1300 to 1650°C. The approach adopted in this work was to statistically design and prepare simulated slags, measure the viscosity as a function of temperature, and develop a model to predict slag viscosity based on slag composition and temperature. Statistical design software was used to select compositions from a candidate set of all possible vertices that will optimally represent the composition space for 10 main components. A total of 21 slag compositions were generated, including 5 actual coal slag compositions. The Arrhenius equation was applied to measured viscosity versus temperature data of tested slags, and the Arrhenius coefficients (A and B in ln(vis) = A + B/T) were expressed as linear functions of the slag composition. The viscosity model was validated using 1) data splitting approach, and 2) viscosity/temperature data of selected slag compositions from the literature that were formulated and melted at Pacific Northwest National Laboratory. The capability of the model to predict the viscosity of coal slags was compared with the model developed by Browning et al. because this model can predict the viscosity of slags from coal ash better than the most commonly used empirical models found in the literature.

  16. Effects of lignite properties on the hydroliquefaction behavior of representative Turkish lignites

    SciTech Connect

    Oener, M.; Bolat, E.; Dincer, S. )

    1992-01-01

    This paper reports on the conversion and yield data obtained for hydroliquefaction of 11 different Turkish lignites in tetralin, anthracene, and creosote oils with or without catalyst at 440{degrees}C and 80 bar that were correlated with the lignite properties obtained from proximate, ultimate, and petrographic analyses. The intercorrelation of experimental results and analytical data was evaluated by both simple linear regression and stepwise multiple linear regression analyses. Simple linear correlations between conversion and yield data with individual lignite parameters are unsatisfactory. An approach utilizing a stepwise multiple linear regression analysis lead to a number of linear equations relating oil yields to ash, sulfur, volatile matter, elemental carbon, maceral, and xylene extract contents of the lignites.

  17. Study on Combustion Characteristics of Lignite in a CFB Boiler

    NASA Astrophysics Data System (ADS)

    Leng, J.; Zou, T. S.; Wu, J. X.; Jiang, C.; Gao, J. L.; Wu, J.; Su, D.; Song, D. Y.

    The shortage of coal promotes the lignite utility in power plant because of the rapid economy development recently. However, lignite is high in moisture content as well as volatile content and low in calorific value. It is very difficult to burn in traditional pulverized coal fired boiler. Circulating fluidized bed (CFB) boiler is an alternative with low pollutant emission. Some CFB boilers are built and put into commercial operation in Northeast China and East Inner Mongolia where lignite is abundant. The operation experiences of these boilers are introduced in this paper. The effect of coal particle size on bottom ash ratio, combustion efficiency, thermal efficiency, pollution emission, and ash deposits in convective heating surface were investigated. It was found that for the lignite fired CFB boiler, the largest coal particle size should be 20 to 40mm to maintain bed material balance. But the bottom ash only shares less than 10% of the total ash. Due to high volatile content in the lignite, the combustion efficiency could achieve more than 99%. Meanwhile, NOx emission was relative low and satisfied national environment protection requirement. It is suggested that flue gas velocity in convective heating surface should be ranged in a certain scope to prevent ash deposit and erosion.

  18. Appraising lignite quality parameters by linguistic fuzzy identification

    SciTech Connect

    Tutmez, B.

    2007-03-15

    Lignite quality parameters have had central importance for power plants. This article addresses a comparative study on fuzzy and regression modeling for estimating the calorific value of lignite, which is one of the quality parameters from the other parameters: moisture, ash, volatile matter, and sulphur content. For the estimations, data driven models were designed based on linguistic fuzzy modeling structures. In addition, estimations of the fuzzy models were compared with linear regression estimations. The great majority of performance evaluations showed that the fuzzy estimations are very satisfactory in estimating calorific value of lignite.

  19. Distribution of coal quality parameters in lignites of northeast Texas

    SciTech Connect

    Crowley, S.S.; Warwick, P.D.; Thomas, R.E.; Mason, W.H.

    1996-12-31

    The distribution of coal quality characteristics was examined in lignites (Wilcox Group, Paleocene-Eocene) near Mt. Pleasant, Texas. Coal quality parameters including ash yield, sulfur forms, moisture, calorific value, and selected potentially hazardous trace elements were plotted on cross sections of lignite beds to determine their stratigraphic distribution. This study has been undertaken as a part of the US Geological Survey`s National Coal Resource Assessment (NCRA) program in the Gulf Coast Lignite Region. The distribution in coal of Hazardous Air Pollutant elements (HAPs), as defined in the Clean Air Act Amendments of 1990, are an important focus of the NCRA program.

  20. Drying grain using a hydrothermally treated liquid lignite fuel

    SciTech Connect

    Bukurov, Z.; Cvijanovic, P.; Bukurov, M.; Ljubicic, B.R.

    1995-12-01

    A shortage of domestic oil and natural gas resources in Yugoslavia, particularly for agricultural and industrial purposes, has motivated the authors to explore the possibility of using liquid lignite as an alternate fuel for drying grain. This paper presents a technical and economic assessment of the possibility of retrofitting grain-drying plants currently fueled by oil or natural gas to liquid lignite fuel. All estimates are based on lignite taken from the Kovin deposit. Proposed technology includes underwater mining techniques, aqueous ash removal, hydrothermal processing, solids concentration, pipeline transport up to 120 km, and liquid lignite direct combustion. For the characterization of Kovin lignite, standard ASTM procedures were used: proximate, ultimate, ash, heating value, and Theological analyses were performed. Results from an extensive economic analysis indicate a delivered cost of US$20/ton for the liquid lignite. For the 70 of the grain-drying plants in the province of Vojvodina, this would mean a total yearly saving of about US $2,500,000. The advantages of this concept are obvious: easy to transport and store, nonflammable, nonexplosive, nontoxic, 30%-40% cheaper than imported oil and gas, domestic fuel is at hand. The authors believe that liquid lignite, rather than an alternative, is becoming more and more an imperative.

  1. Slag Behavior in Gasifiers. Part II: Constitutive Modeling of Slag

    SciTech Connect

    Massoudi, Mehrdad; Wang, Ping

    2013-02-07

    The viscosity of slag and the thermal conductivity of ash deposits are among two of the most important constitutive parameters that need to be studied. The accurate formulation or representations of the (transport) properties of coal present a special challenge of modeling efforts in computational fluid dynamics applications. Studies have indicated that slag viscosity must be within a certain range of temperatures for tapping and the membrane wall to be accessible, for example, between 1,300 °C and 1,500 °C, the viscosity is approximately 25 Pa·s. As the operating temperature decreases, the slag cools and solid crystals begin to form. Since slag behaves as a non-linear fluid, we discuss the constitutive modeling of slag and the important parameters that must be studied. We propose a new constitutive model, where the stress tensor not only has a yield stress part, but it also has a viscous part with a shear rate dependency of the viscosity, along with temperature and concentration dependency, while allowing for the possibility of the normal stress effects. In Part I, we reviewed, identify and discuss the key coal ash properties and the operating conditions impacting slag behavior.

  2. Compatibility of water-cooled chromia-containing refractories with a high iron oxide acidic coal-ash slag at 1575/sup 0/C

    SciTech Connect

    Kennedy, C.R.

    1981-12-01

    Sixteen water-cooled refractories were exposed to a synthetic high iron oxide acidic coal slag. The importance of high chromia content and density in minimizing corrosive attack was evident. The beneficial effect of water cooling was also demonstrated. All the refractories reacted with the slag to form complex intermediate spinel layers. Refractories high in chromia resist fluxing by iron oxide better than refractories high in alumina.

  3. Slag pit practices to improve slag quality

    SciTech Connect

    Mertdogan, A.; Gambol, F.C.; Spaeth, J.R.; Zbos, J.; Batka, R.; Tolliver, D.

    1996-12-31

    Slag quality had deteriorated recently. Without the explicit approval for slag quality by the Illinois Department of Transportation, the slag would not be saleable. Disposal of slag to landfills was going to be an expensive solution and rife with environmental concerns. A slag quality control program embarked on in mid-1994 restored slag quality to desired specifications. This paper describes the changes in slag pit practice adopted following extensive tests performed on cooling slag under controlled conditions.

  4. JV Task 75 - Lignite Fuel Enhancement via Air-Jigging Technology

    SciTech Connect

    Jason Lamb; Steven Benson; Joshua Stanislowski

    2007-03-01

    Several North Dakota lignite coals from the Falkirk Mine were processed in a 5-ton-per-hour dry coal-cleaning plant. The plant uses air-jigging technology to separate undesirable ash constituents as well as sulfur and mercury. The results of this study indicate average ash, sulfur, and mercury reductions on a weight basis of 15%, 22%, and 28%, respectively. The average heating value was increased by 2% on a Btu/lb basis. Two computer models were used to understand the impact of a cleaned fuel on boiler performance: PCQUEST{reg_sign} and Vista. The PCQUEST model indicated improvements in slagging and fouling potential when cleaned coals are used over feed coals. The Vista model was set up to simulate coal performance and economics at Great River Energy's Coal Creek Station. In all cases, the cleaned fuel performed better than the original feed coal, with economic benefits being realized for all fuels tested. The model also indicated that one fuel considered to be unusable before cleaning was transformed into a potentially salable product. While these data indicate full-scale implementation of air-jigging technology may be beneficial to the mine and the plant, complete economic analysis, including payback period, is needed to make the final decision to implement.

  5. Naturally occurring radioactive materials (NORMs) generated from lignite-fired power plants in Kosovo.

    PubMed

    Hasani, F; Shala, F; Xhixha, G; Xhixha, M K; Hodolli, G; Kadiri, S; Bylyku, E; Cfarku, F

    2014-12-01

    The energy production in Kosovo depends primarily on lignite-fired power plants. During coal combustion, huge amounts of fly ash and bottom ash are generated, which may result in enriched natural radionuclides; therefore, these radionuclides need to be investigated to identify the possible processes that may lead to the radiological exposure of workers and the local population. Lignite samples and NORMs of fly ash and bottom ash generated in lignite-fired power plants in Kosovo are analyzed using a gamma-ray spectrometry method for the activity concentration of natural radionuclides. The average activity concentrations of (40)K, (226)Ra and (232)Th in lignite are found to be 36 ± 8 Bq kg(-1), 9 ± 1 Bq kg(-1) and 9 ± 3 Bq kg(-1), respectively. Indications on the occurrence and geochemical behavior of uranium in the lignite matrix are suggested. The activity concentrations of natural radionuclides in fly ash and bottom ash samples are found to be concentrated from 3 to 5 times that of the feeding lignite. The external gamma-ray absorbed dose rate and the activity concentration index are calculated to assess the radiological hazard arising from ash disposal and recycling in the cement industry. PMID:25233215

  6. COFIRING BIOMASS WITH LIGNITE COAL

    SciTech Connect

    Darren D. Schmidt

    2002-01-01

    The University of North Dakota Energy & Environmental Research Center, in support of the U.S. Department of Energy's (DOE) biomass cofiring program, completed a Phase 1 feasibility study investigating aspects of cofiring lignite coal with biomass relative to utility-scale systems, specifically focusing on a small stoker system located at the North Dakota State Penitentiary (NDSP) in Bismarck, North Dakota. A complete biomass resource assessment was completed, the stoker was redesigned to accept biomass, fuel characterization and fireside modeling tests were performed, and an engineering economic analysis was completed. In general, municipal wood residue was found to be the most viable fuel choice, and the modeling showed that fireside problems would be minimal. Experimental ash deposits from firing 50% biomass were found to be weaker and more friable compared to baseline lignite coal. Experimental sulfur and NO{sub x} emissions were reduced by up to 46%. The direct costs savings to NDSP, from cogeneration and fuel saving, results in a 15- to 20-year payback on a $1,680,000 investment, while the total benefits to the greater community would include reduced landfill burden, alleviation of fees for disposal by local businesses, and additional jobs created both for the stoker system as well as from the savings spread throughout the community.

  7. The distribution of trace elements in Turkish lignites in Western Anatolia and the Thrace Basin

    SciTech Connect

    Palmer, C.A.; Tuncali, E.; Finkelman, R.

    1999-07-01

    The United States Geological Survey (USGS) and the General Directorate of Mineral Research and Exploration in Turkey (Maden Tetkik ve Arama:MTA) are working together to provide a more complete understanding of the chemical properties of lignites from major Turkish lignite producing areas. The project is a part of the USGS effort to produce an international coal database and is part of the ``Technological and Chemical properties of Turkish Lignite Inventory Project'' being conducted by the MTA General Directorate. The lignites in Turkey formed in several different depositional environments at different geologic times and have differing chemical properties. The Eocene lignites are limited to northern Turkey. Oligocene lignites, in the Trace Basin of northwestern Turkey, are intercalated with marine sediments. Miocene lignites are generally located in western Turkey. These coal deposits have relatively abundant reserves, with limnic characteristics. The Pliocene-Pleistocene lignites are found in the eastern part of Turkey. Most of these lignites have low calorific values, high moisture and high ash contents. The majority of the lignite extraction is worked in open-pit mines. Turkish lignite production is used mainly by power plants; small amounts are used by households and in industry. All the samples in this study were collected as channel samples of the beds. Analyses of 71 coal samples (mostly lignites) have been completed for 54 elements using various analytical techniques including inductively coupled plasma emission and mass spectrometry, instrumental neutron activation analysis and various single element techniques. Many of these lignites have elemental concentrations similar to those of US lignites. However, maximum or mean concentrations of B, Cr, Cs, Ni, As, Br, Sb, Cs and U in Turkey were higher than the corresponding maximum or mean found in either of the Fort Union or Gulf Coast basins, the two most productive lignite basins in the U.S.

  8. Briquettability of lignite and woody wastes composite fuel

    SciTech Connect

    Beker, U.G.

    2000-03-01

    Woody wastes have favorable burning characteristics compared to lignite, as well as low ash content and reduced smoke emission. The aim of this study was to blend lignite with woody wastes to obtain a solid fuel that retains the advantageous characteristics of woody materials. Blends with lignite were made up with 7, 9, 12, 15, and 20% of waste and then briquetted under pressures of 400, 550, 700, and 800 MPa. Sunflower shell, sawdust, and paper mill wastes were used in different amounts with molasses as binder. Studies were carried out on a laboratory scale to determine optimum parameters for briquetting, such as moisture content of lignite and pressure. Briquetting of lignite without waste materials produces products of low strength. The strongest briquettes were obtained with waste contents of 12--20% and lignite moisture contents of 10--12% at briquetting pressures of 550, 700, and 800 MPa. Briquettes with adequate mechanical strength are obtained from lignite-waste blends with the addition of 8% molasses.

  9. Statistical tests for prediction of lignite quality

    SciTech Connect

    C.J. Kolovos

    2007-06-15

    Domestic lignite from large, bucket wheel excavators based open pit mines is the main fuel for electricity generation in Greece. Lignite from one or more mines may arrive at any power plant stockyard. The mixture obtained constitutes the lignite fuel fed to the power plant. The fuel is sampled in regular time intervals. These samples are considered as results of observations of values of spatial random variables. The aim was to form and statistically test many small sample populations. Statistical tests on the values of the humidity content, the ash-water free content, and the lower heating value of the lignite fuel indicated that the sample values form a normal population. The Kolmogorov-Smirnov test was applied for testing goodness-of-fit of sample distribution for a three year period and different power plants of the Kozani-Ptolemais area, western Macedonia, Greece. The normal distribution hypothesis can be widely accepted for forecasting the distribution of values of the basic quality characteristics even for a small number of samples.

  10. Ensuring slagging-free operation of a boiler equipped with hammer mills in firing brown coal with low-melting ash

    NASA Astrophysics Data System (ADS)

    Arkhipov, A. M.; Dorogoi, G. A.

    2011-04-01

    The possibility of ensuring slagging-free operation of heating surfaces in firing Pereyaslov brown coal is considered taking the PK-38 boiler at the Krasnoyarsk GRES-2 district power station as an example. Retrofitting of burners and nozzles and setting up of a recirculation-vortex flame are recommended.

  11. Slag-based saltstone formulations

    SciTech Connect

    Langton, C.A.

    1987-08-25

    Approximately 400 x 10/sup 6/ liters of low-level alkaline salt solution will be treated at the Savannah River Plant (SRP) Defense Waste Processing Facility (DWPF) prior to disposal in concrete vaults at SRP. Treatment involves removal of CS/sup +/ and Sr/sup +2/ followed by solidification and stabilization of potential contaminants in saltstone, a hydrated ceramic waste form. Chromium, technetium, and nitrate releases from saltstone can be significantly reduced by substituting hydraulic blast furnace slag for portland cement in the formulation designs. Slag-based mixes are also compatible with Class F fly ash used in saltstone as a functional extender to control heat of hydration and reduce permeability. A monolithic waste form is produced by the hydration of the slag and fly ash. Soluble ion release (NO/sub 3//sup -/) is controlled by the saltstone microstructure. Chromium and technetium are less leachable from slag mixes compared to cement-based waste forms because these species are chemically reduced to a lower valence state by ferrous iron in the slag and precipitated as relatively insoluble phases, such as CR(OH)/sub 3/ and TcO/sub 2/. 5 refs., 4 figs., 4 tabs.

  12. LIGNITE FUEL ENHANCEMENT

    SciTech Connect

    Charles Bullinger

    2005-06-07

    This 3rd quarterly Technical Progress Report for the Lignite Fuel Enhancement Project summarizes activities from January 1st through March 31st of 2005. It also summarizes the subsequent purchasing activity and final dryer/process design.

  13. LIGNITE FUEL ENHANCEMENT

    SciTech Connect

    Charles Bullinger

    2005-07-07

    This 4th quarterly Technical Progress Report for the Lignite Fuel Enhancement Project summarizes activities from April 1st through June 30th of 2005. It also summarizes the subsequent purchasing activity and dryer/process construction.

  14. Lignite Fuel Enhancement

    SciTech Connect

    Charles Bullinger

    2006-02-03

    This 6th quarterly Technical Progress Report for the Lignite Fuel Enhancement Project summarizes activities from October 1st through December 31st of 2005. It also summarizes the subsequent purchasing activity and dryer/process construction. Hypothesis remains the same. We will be able to dry lignite an increment to benefit the performance of and reduce emissions from a coal burning electric power generating station.

  15. Potentially toxic elements in lignite and its combustion residues from a power plant.

    PubMed

    Ram, L C; Masto, R E; Srivastava, N K; George, J; Selvi, V A; Das, T B; Pal, S K; Maity, S; Mohanty, D

    2015-01-01

    The presence of potentially toxic elements in lignite and coal is a matter of global concern during energy extraction from them. Accordingly, Barsingsar lignite from Rajasthan (India), a newly identified and currently exploited commercial source of energy, was evaluated for the presence of these elements and their fate during its combustion. Mobility of these elements in Barsingsar lignite and its ashes from a power plant (Bikaner-Nagaur region of Thar Desert, India) is presented in this paper. Kaolinite, quartz, and gypsum are the main minerals in lignite. Both the fly ash and bottom ash of lignite belong to class-F with SiO₂ > Al₂O₃ > CaO > MgO. Both the ashes contain quartz, mullite, anhydrite, and albite. As, In, and Sr have higher concentration in the feed than the ashes. Compared to the feed lignite, Ba, Co, U, Cu, Cd, and Ni are enriched (10-5 times) in fly ash and Co, Pb, Li, Ga, Cd, and U in bottom ash (9-5 times). Earth crust-normalization pattern showed enrichment of Ga, U, B, Ag, Cd, and Se in the lignite; Li, Ba, Ga, B, Cu, Ag, Cd, Hg, Pb, and Se, in fly ash; and Li, Sr, Ga, U, B, Cu, Ag, Cd, Pb, and Se in bottom ash. Hg, Ag, Zn, Ni, Ba, and Se are possibly associated with pyrite. Leaching test by toxicity characteristic leaching procedure (TCLP) showed that except B all the elements are within the safe limits prescribed by Indian Standards. PMID:25446718

  16. Slagging gasifier

    SciTech Connect

    Schulz, H.

    1982-07-20

    A slagging gasifier for the gasification of coal and organic waste materials is disclosed. The gasifier includes a vertical blast furnace having a hearth section at the bottom thereof. A slag tap hole is formed in hearth section and opens into a quenching vessel. A honeycomb structure is formed on the inner surface of said hearth section in the area surrounding said slag tap hole, and the inner wall of the hearth section. A plurality of tuyeres extend into the hearth section and feed the furnace with steam and oxygen so as to permit the oxidation of coal and organic waste materials fed into the furnace. As a result of the oxidation, gas and molten slag are formed in the furnace. The slag is collected in the hearth section and exits the hearth section via the tap hole. One or more conduits are provided for recycling (Either internally or externally) the gas exiting the top of the gasifier with the tars, oils, and particulates entrained therein to the partial combustion zone of the gasifier where the tars, oils and particulates are converted to noncondensible gases. A portion of the tar-free product gas is removed from an intermediate point in the gasifier below the pyrolysis and coking zone.

  17. Modeling of a coal-fired slagging combustor: Development of a slag submodel

    SciTech Connect

    Wang, X.H.; Zhao, D.Q.; He, L.B.; Jiang, L.Q.; He, Q.; Chen, Y.

    2007-05-15

    In a slagging combustor or furnace, the high combustion temperature makes the molten slag layer cover the wall and capture the particles. If these particles contain combustible matter, they will continue to burn on the running slag. As a result, the total amount of ash deposition will be much greater than that in dry-wall combustors and the total heat flux through the deposition surface will change greatly. Considering the limitations of existing simulation methods for slagging combustion, this paper introduces a new wall burning model and slag flow model from the analysis of particle deposition phenomena. Combined with a conventional combustion simulation program, the total computational frame is introduced. From comparisons of simulation results from several kinds of methods with experimental data, the conclusion is drawn that the conventional simulation methods are not very suitable for slagging combustion and the wall burning mechanism should be considered more thoroughly. (author)

  18. The effects of advanced physical coal cleaning on mineral matter and ash composition and its relationship to boiler slagging and fouling potential

    SciTech Connect

    DeMaris, P.J.; Read, R.B.; Camp, L.R. )

    1988-06-01

    Recent progress in cleaning medium to high-sulfur coals from the Illinois Basic by advanced flotation methods (Read et al., 1987a) has led to the need to evaluate changes in the ash fusion temperatures of deep cleaned coal. Because the alumina and silica-rich clay minerals and coarse pyrite are more easily removed during coal cleaning than finely disseminated pyrite, it is believed that deeply cleaned coal products may have lower ash fusion temperatures because of altered composition of the remaining ash. To investigate this question a suite of six coals, cleaned to various degrees, were analyzed for ash chemistry (ASTM method on 750/sup 0/C Ash), ash fusion temperatures, perographic variation and mineralogic composition. The samples include the two major mined seams in the Illinois Basin, the Herrin (No. 6) and Springfield (No. 5) Coal Members, as well as the widely used Pittsburgh seam. In this abbreviated paper results for ash chemistry and ash fusion analysis are reported and evaluated. The coals tested contain a variety of minerals. For a run-of-mine (ROM) or channel sample the typical mineral suite listed in decreasing abundance order is: various clay minerals (kaolinite, illite and expandables), pyrite/marcasite, quartz, calcite and other minerals. As these coals are cleaned certain components are more easily removed, such as the free clay and quartz (largely from floor and roof materials) and coarse pyrite/marcasite and calcite from the coal seam. While some of the mineral matter can be liberated with minimum crushing and removed by gravity separation without significant Btu loss, the finely dispersed (framboidal) pyrite requires extensive grinding to achieve significant liberation levels.

  19. Humic preperations from Russian lignites

    SciTech Connect

    Rodeh, V.V.; Ryzhkov, O.G.

    1994-12-31

    THe objective of this work was to study lignites as the precursor materials to humic substances. Lignites contain humic substances primarily as humic acids. Their extraction requires the processing of coals with alkali.

  20. Lignite Fuel Enhancement

    SciTech Connect

    Charles Bullinger; Nenad Sarunac

    2010-03-31

    Pulverized coal power plants which fire lignites and other low-rank high-moisture coals generally operate with reduced efficiencies and increased stack emissions due to the impacts of high fuel moisture on stack heat loss and pulverizer and fan power. A process that uses plant waste heat sources to evaporate a portion of the fuel moisture from the lignite feedstock in a moving bed fluidized bed dryer (FBD) was developed in the U.S. by a team led by Great River Energy (GRE). The demonstration was conducted with Department of Energy (DOE) funding under DOE Award Number DE-FC26-04NT41763. The objectives of GRE's Lignite Fuel Enhancement project were to demonstrate reduction in lignite moisture content by using heat rejected from the power plant, apply technology at full scale at Coal Creek Station (CCS), and commercialize it. The Coal Creek Project has involved several stages, beginning with lignite drying tests in a laboratory-scale FBD at the Energy Research Center (ERC) and development of theoretical models for predicting dryer performance. Using results from these early stage research efforts, GRE built a 2 ton/hour pilot-scale dryer, and a 75 ton/hour prototype drying system at Coal Creek Station. Operated over a range of drying conditions, the results from the pilot-scale and prototype-scale dryers confirmed the performance of the basic dryer design concept and provided the knowledge base needed to scale the process up to commercial size. Phase 2 of the GRE's Lignite Fuel Enhancement project included design, construction and integration of a full-scale commercial coal drying system (four FBDs per unit) with Coal Creek Units 1 and 2 heat sources and coal handling system. Two series of controlled tests were conducted at Coal Creek Unit 1 with wet and dried lignite to determine effect of dried lignite on unit performance and emissions. Wet lignite was fired during the first, wet baseline, test series conducted in September 2009. The second test series was performed

  1. Radioenvironmental survey of the Megalopolis lignite field basin.

    PubMed

    Rouni, P K; Petropoulos, N P; Anagnostakis, M J; Hinis, E P; Simopoulos, S E

    2001-05-14

    The Megalopolis lignite field basin in southern Greece, with Megalopolis-A and B lignite-fired power plants in operation (total 900 MW), has been repeatedly investigated during the past 25 years by the Nuclear Engineering Section of the National Technical University of Athens (NES-NTUA). The present work aims at an integrated radioenvironmental approach leading to the dose assessment to the public and to the plants staff. This approach includes systematic sampling of lignite and barren at the local lignite mines feeding the power plants and sampling of lignite, fly-ash and bottom ash at the power plants for the determination of the activity of the natural radionuclides 226Ra, 232Th, 40K, 234Th and 210Pb. Furthermore, the following measurements and samplings were conducted in 25 selected sites within 10 km around the power plants: soil sampling for the determination of the above radionuclides, radon concentration and exhalation rate measurements, soil gas radon concentration measurements, dose measurements and calculations, determination of air-particulate matter concentration, etc. The results obtained allowed for the mapping of the parameters studied which lead to useful conclusions. Dosimetric calculations for the population living around the power plants and the plants staff were also performed based on the guidance of UNSCEAR (1982 report). PMID:11379921

  2. Viscosity measurements and empirical predictions for coal slags

    SciTech Connect

    Matyas, Josef; Sundaram, S K; Rodriguez, Carmen P; Heredia-Langner, Alejandro; Arrigoni, Benjamin M

    2009-10-25

    Slag viscosity in slagging coal gasifier is an important factor affecting the gasification regime and operating cost. Most of the empirical viscosity models of coal slags that are available in the literature are applicable to only limited ranges of temperature and composition. To develop a reliable slag viscosity model, additional data are needed. Slag viscosity was measured under air or reducing atmosphere (calculated pO2~1.2 10-12 atm at 1400°C) at temperatures in the range of 1150-1550°C on 63 statistically designed slags, including 5 actual coal slag compositions and 4 validation slag compositions. The Arrhenius equation, with Arrhenius coefficients A = constant and B expressed as linear function of mass fractions of nine major components was used to fit the viscosity/temperature data. This Arrhenius relationship represents the viscosity–temperature relationship of tested slags reasonably well, = 0.981 (reducing atmosphere) and = 0.974 (air atmosphere). The validation of the model with four randomly selected slags (two from the SciGlass database and two from experimental design) indicated an accurately measured viscosity-temperature data and a fairly good predictive performance of slag viscosity models over designed compositions. The capability of the developed model to predict the viscosity of coal slags under reducing atmosphere was found to be a superior to a number of the most commonly used empirical models in the literature that are based on simplified oxide melts and British or Australian coal ash slags.

  3. Overcoming ash deposition: A case study. Part 1: Measurements and modeling -- The research perspective

    SciTech Connect

    McCollor, D.P.; Gunderson, J.R.; Zygarlicke, C.J.; Backman, B.C.; Blohm, C.L.

    1998-12-31

    Coyote Station of Montana Dakota Utilities was experiencing increasingly severe ash slagging and fouling in its 425-MW cyclone boiler while burning a Beulah lignite coal from three seams of the adjoining Knife River Coal Mining Company Beulah Mine. A dual approach of assessing coal quality and examining plant operating characteristics was implemented to formulate mine-planning, coal-blending, and boiler-operating strategies to mitigate the slagging and fouling. Advanced coal analyses were performed on core samples in advance of the active mining operation for the three mine seams. Concurrently, a boiler inspection protocol was implemented by the plant personnel to quantitatively track the progress of ash deposition. A field test at Coyote Station was conducted to obtain furnace gas temperatures, ash deposit samples, and crucial operating data. Other valuable information was obtained by correlation of day-to-day mining records with plant operating data over a several-month period. Initial examination of coal loadout records prior to fouling-related outages suggested possible mine areas with significant fouling potential. This was supported by PCQUEST fireside performance modeling and by equilibrium thermodynamic calculations of ash viscosity, with sodium calcium silicates and sulfates the main contributors to problematic deposition. Correlations of the PCQUEST slagging and fouling index values were developed for this specific coal and mine to provide indicators of coal quality based on standard American Society for Testing and Materials (ASTM) analysis parameters. This allowed data from a large number of previous core samples to be used to map coal fouling and slagging potential on a minewide basis. Two areas of high-fouling coal were discovered across the lateral extent of the mine. In the vertical section, the top coal seam revealed much lower fouling propensity than the lower two seams. The same correlations also permitted assessment of the fouling and slagging

  4. Binderless lignite briquetting

    SciTech Connect

    Mall, L.

    1996-12-31

    Almost all of Germany`s lignite deposits were formed during the Tertiary Period 20 to 40 million years ago. Germany`s entire coal resources amount to something over 100 billion tonnes, of which roughly 57 billion tonnes may be economically mined with today`s mining technology and energy prices. This means that Germany has more than 10% of the world`s economically mineable coal reserves. Lignite production on an economically significant scale is taking place in the following mining areas: (1) Rhine Mining Area, (2) Helmstedt Mining Area, (3) Central German Mining Area, and (4) Lusatian Mining Area.

  5. Refractory failure in slagging gasifiers

    SciTech Connect

    Bennett, James P.; Kwong, Kyei-Sing

    2004-08-01

    Slagging gasifiers are used to produce chemicals and/or electricity from feedstocks such as coal and/or petroleum coke. A gasifier environment includes pressures from 400 to 1000 psi, temperatures from 1250-1550 C, are cyclic, reducing gases of CO and H2, and molten ash that interacts with the refractory liner materials. The high Cr2O3 refractory liners of gasifiers fail within 3 to 24 months due to slag attack at elevated temperatures. Gasifier users seek materials with increased reliability and service life. The causes of refractory failure and efforts to increase refractory service life are discussed. Mechanisms involving corrosion and slag infiltration/spalling are the main causes of refractory wear. The reduction of slag penetration can reduce hot face lining wear. The performance of high Cr2O3-Al2O3 materials with phosphate additions were evaluated. Phosphate additions were found to have comparable wear and physical properties to materials with no additions, and to have good slag penetration resistance. Field trials in a gasifier are needed to clarify the potential of the materials.

  6. Lignite combustion test project interim report: Tests L101-L114

    SciTech Connect

    Phillips, K.E.; Wilson, K.B.

    1980-08-01

    Fluidized bed combustion research on North Dakota lignite is being performed by Combustion Power Company, Inc. under contract to Grand Forks Energy Technology Center in a 7 sq ft Atmospheric Fluid Bed Combustor. A series of 14 parameteric tests have been completed in which various combinations of bed temperature, superficial velocity, excess air, and limestone Ca/S ratios made up the test matrix. Twelve of the 14 tests used ash recycle. The test results extend the lignite combustion characteristics determined from GFETC tests on smaller reactors with respect to: (1) sulfur retention on lignite ash and supplemental sorbents; (2) ash and bed agglomeration problems; (3) effect of operational conditions and bed characteristics on heat transfer coeffficient; (4) ash reinjection; and (5) flue gas pollutants. This interim report summarizes the test setup, test procedures and test results, describes operational problems, and provides observations noted during the tests and on post-test inspections.

  7. Lignite Research Project.

    ERIC Educational Resources Information Center

    Robinson, Fred

    Since it became known in l979 that the Arkansas Power and Light Company was going to build a large electricity generating plant near Hampton and that there would be a lignite mining operation established there to support the power plant, the Warren public schools have been preparing to meet the impact on the schools. Because it was assumed that…

  8. Properties and reserves of lignite in the Aydin-Sahinali field, Turkey

    SciTech Connect

    Kirhan, S.; Inaner, H.; Nakoman, E.; Karayigit, A.I.

    2007-07-01

    This study focuses on some lignite properties and calculation of lignite reserves with two classical (isopach and polygon) methods in the Aydin-Sahinali field, Turkey, which is located in the western Turkey. This field has been mined by a private coal company since 1960 by open-cast and mainly underground mining methods. The producing lignites are consumed in domestic heating and industrial factories around Aydin. The metamorphic rocks of Palaezoic age form the basement of the coal field. The lignite-bearing unit of Miocene age, from bottom to the top, consists mainly of pebblestone, lignite and clayey lignite, siltstone with sandstone lenses, white colored claystone, clayey limestone and silisified limestone lenses. This unit in the lignite field was unconformably overlain by Pliocene unconsolidated sands and gravels. Three hundred seventy-three borehole data have been evaluated, and this study shows that a relatively thick and lateral extensive lignite seam has a mineable thickness of 1.6-14.4 m. The core samples from boreholes in panels in the lignite field indicate that the coal seam, on an as-received basis, contains high moisture contents (17.95-23.45%, average), high ash yields (16.30-26.03%, average), relatively high net calorific values (3,281-3,854 kcal/kg, average), and low total sulfur contents (1.00-1.22%, average). The remaining lignite potential in the Aydin-Sahinali lignite field was calculated as a 4.7 Mt of measured and a 2.9 Mt of mineable lignite-reserves.

  9. Correlation between the critical viscosity and ash fusion temperatures of coal gasifier ashes

    SciTech Connect

    Hsieh, Peter Y.; Kwong, Kyei-Sing; Bennett, James

    2015-09-27

    Coal gasification yields synthesis gas, an important intermediate in chemical manufacturing. It is also vital to the production of liquid fuels through the Fischer-Tropsch process and electricity in Integrated Gasification Combined Cycle power generation. Minerals naturally present in coal become molten in entrained-flow slagging gasifiers. Molten coal ash slag penetrates and dissolves refractory bricks, leading to costly plant shutdowns. The extent of coal ash slag penetration and refractory brick dissolution depends on the slag viscosity, the gasification temperature, and the composition of slag and bricks. Here, we measured the viscosity of several synthetic coal ash slags with a high-temperature rotary viscometer and their ash fusion temperatures through optical image analysis. We made all measurements in a carbon monoxide-carbon dioxide reducing atmosphere that approximates coal gasification conditions. Empirical correlation models based on ash fusion temperatures were used to calculate critical viscosity temperatures based on the coal ash compositions. These values were then compared with those obtained from thermodynamic phase-transition models. Finally, an understanding of slag viscosity as a function of ash composition is important to reducing refractory wear in slagging coal gasifiers, which would help to reduce the cost and environmental impact of coal for chemical and electricity production.

  10. Selective oil agglomeration of lignite

    SciTech Connect

    Halime Abakay Temel; Volkan Bozkurt; Arun Kumar Majumder

    2009-01-15

    In this study, desulfurization and deashing of Adiyaman-Glbai lignite by the agglomeration method were studied. For this purpose, three groups of agglomeration experiments were made. The effects of solid concentration, bridging liquid type and dosage, pH, and screen size on the agglomeration after desliming were investigated in the first group of experiments. The effects of lake water and sea water (the Mediterranean Sea water, the Aegean Sea water, and the Black Sea water) on the agglomeration were investigated in the second group of experiments. The effects of different salts (NaCl, MgCl{sub 2}, and FeCl{sub 3}) on the agglomeration were investigated in the third group of experiments. Agglomeration results showed that the usage of sea waters and soda lake water in the agglomeration medium had a positive effect on the reduction of total sulfur content of agglomerates. In addition, the usage of NaCl, MgCl{sub 2}, and FeCl{sub 3} in the agglomeration medium had a positive effect on the ash content reduction of the agglomerates. 27 refs., 10 figs., 6 tabs.

  11. Cheap carbon sorbents produced from lignite by catalytic pyrolysis

    SciTech Connect

    Kuznetsov, B.N.; Schchipko, M.L.

    1995-12-01

    Some data are presented describing the new technology of carbon sorbent production from powdered lignite in the installation with fluidized bed of catalyst. It was shown the different types of char products with extended pore structure and high sorption ability can be produced from cheap and accessible lignite of Kansk-Achinsk coal pit in pilot installation with fluidized bed of Al-Cu-Cr oxide catalyst or catalytically active slag materials. In comparison with the conventional technologies of pyrolysis the catalytic pyrolysis allows to increase by 3-5 times the process productivity and to decrease significantly the formation of harmful compounds. The latter is accomplished by complete oxidation of gaseous pyrolysis products in the presence of catalysts and by avoiding the formation of pyrolysis tars - the source of cancerogenic compounds. The technology of cheap powdered sorbent production from lignites makes possible to obtain from lignite during the time of pyrolysis only a few seconds char products with porosity up to 0.6 cm{sup 3} /g, and specific surface area more than 400 m{sup 3} /g. Some methods of powdered chars molding into carbon materials with the different shape were proved for producing of firmness sorbents. Cheap carbon sorbents obtained by thermocatalytic pyrolysis can be successfully used in purification of different industrial pollutants as one-time sorbent or as adsorbents of long-term application with periodic regeneration.

  12. Overcoming ash deposition: A case study. Part 2: Application of model reaps benefits -- The utility perspective

    SciTech Connect

    Backman, B.C.; Gunderson, J.R.

    1998-12-31

    The Montana-Dakota Utilities (MDU) Company Coyote Station is a 425-MW Babcock and Wilcox cyclone-fired unit commissioned in 1981. The plant was designed to fire a high-ash-, high-sodium-content lignite from the adjacent Knife River Coal Mining Company (KRCMC) Beulah Mine. In recent years, the Coyote Station had been experiencing increasingly severe fouling and slagging, resulting in more frequent and often unscheduled outages. A joint project with the Energy and Environmental Research Center to address this problem was instituted by MDU and KRCMC. Plant operating parameters were reviewed and compared with historical coal data and PCQUEST modeling to identify fuel and operating effects on convective pass ash fouling. Results indicated separate and combined effects of fuel quality and operating parameters leading to troublesome ash-fouling tendencies. Historically, Coyote Station was down for cleaning between three and four times per year as a result of problematic boiler tube ash fouling and has been down as many as five times per year. Outages represent a considerable expense to the utility in both cleaning costs and lost generating revenue. Application of the model at the mine to deliver a consistent product, using the model at the plant to track incoming coal quality, and setting reasonable operating limits based on incoming coal quality have resulted in improved operation of the plant. Current operations suggest that between two and three outages per year on average will be required to maintain the unit.

  13. Concentration of low-grade lignites by multi-stage processing (washing, semicoking, magnetic separation)

    SciTech Connect

    Onal, G.; Renda, D.; Dogan, Z.

    1999-07-01

    Tavanl-Omerler lignite deposit with a reserve of 264 million tons forms an important section of Turkish lignites. This lignitic coal was subjected to washing, semi-coking and magnetic separation so that the total sulphur and ash contents were reduced from 4.08 % to 1.27 and 15.64 % to 8.5 % respectively. The calorific value of the solid fuel was raised from 5030 Kcal/kg to 6727 Kcal/kg and the volatiles can also be used after sulphur removal. This process appears to be feasible as a clean coal production from the point of energy efficiency. A short economic analysis is also presented.

  14. LIGNITE FUEL ENHANCEMENT

    SciTech Connect

    Charles Bullinger

    2004-10-29

    This 1st quarterly Technical Progress Report for the Lignite Fuel Enhancement Project explains what has transpired since Great River Energy was selected to negotiate the Cooperative agreement in February of 2003. The report will summarize Pre-award activities and any other activity since signature of the contract on July 9th of this year. It also summarizes the subsequent purchasing activity and final dryer/process design up to September 30th of 2004.

  15. The washability of lignites for clay removal

    SciTech Connect

    Oteyaka, B.; Yamik, A.; Ucar, A.; Sahbaz, O.; Demir, U.

    2008-07-01

    In the washability research of the Seyitomer Lignites (Kutahya-Turkey), with lower calorific value (1,863 kcal/kg) and high ash content (51.91%), by heavy medium separation, it was found out that middling clay in the coal had an effect to change the medium density. To prevent this problem, a trommel sieve with 18 and 5 mm aperture diameter was designed, and the clay in the coal was tried to be removed using it before the coal was released to heavy medium. Following that, the obtained coal in -100 + 18 mm and -18 + 5 mm fractions was subjected to sink and float test having 1.4 gcm{sup -3} and 1.7 gcm{sup -3} medium densities (-5 mm fraction will be evaluated in a separate work). Depending on the raw coal, with the floating of -100 + 18 mm and -18 + 5 mm size fraction in 1.4 gcm{sup -3} medium density, clean coal with 60.10% combustible matter recovery, 19.12% ash, and 3,150 kcal/kg was obtained. Also floating of the samples sinking in 1.4 gcm{sup -3} in the medium density (1.7 gcm{sup -3}), middling with 18.70% combustible matter recovery, 41.93% ash, 2,150 kcal/kg, and tailing having 78.31% ash were obtained.

  16. A preliminary report on a zone containing thick lignite beds, Denver Basin, Colorado

    USGS Publications Warehouse

    Soister, Paul E.

    1973-01-01

    hand pressure. Quality of the lignite is lowered by the non-coal partings and, locally at least, by some small blebs and balls of clay in the lignite itself, especially at the base. Available analyses indicate that the following general figures, on an as-received basis, may be applied to relatively clean lignite from this zone: 6,000-7,000 Btu, 20-35 percent moisture, 8-18 percent ash, and 0.3-0.5 percent sulfur. Rank of the lignite is lignite A as calculated by the formulas of the American Society for Testing and . Materials (ASTM), although some parts, especially of deeper beds, may be as high as subbituminous C coal in rank. Best utilization of the lignite probably would be by gasification, liquefaction, or similar methods, because of the numerous non-coal partings and low quality. The thickest known lignite bed is estimated to contain at least 1.25 billion short tons of lignite. Two methods of roughly estimating the order of magnitude of lignite resources, in beds at least 4 feet thick and within 1,000 feet of the surface in this zone, indicate resources are on the order of 20 billion tons.

  17. COAL SLAGGING AND REACTIVITY TESTING

    SciTech Connect

    Donald P. McCollor; Kurt E. Eylands; Jason D. Laumb

    2003-10-01

    Union Fenosa's La Robla I Power Station is a 270-MW Foster Wheeler arch-fired system. The unit is located at the mine that provides a portion of the semianthracitic coal. The remaining coals used are from South Africa, Russia, Australia, and China. The challenges at the La Robla I Station stem from the various fuels used, the characteristics of which differ from the design coal. The University of North Dakota Energy & Environmental Research Center (EERC) and the Lehigh University Energy Research Center (LUERC) undertook a program to assess problematic slagging and unburned carbon issues occurring at the plant. Full-scale combustion tests were performed under baseline conditions, with elevated oxygen level and with redistribution of air during a site visit at the plant. During these tests, operating information, observations and temperature measurements, and coal, slag deposit, and fly ash samples were obtained to assess slagging and unburned carbon. The slagging in almost all cases appeared due to elevated temperatures rather than fuel chemistry. The most severe slagging occurred when the temperature at the sampling port was in excess of 1500 C, with problematic slagging where first-observed temperatures exceeded 1350 C. The presence of anorthite crystals in the bulk of the deposits analyzed indicates that the temperatures were in excess of 1350 C, consistent with temperature measurements during the sampling period. Elevated temperatures and ''hot spots'' are probably the result of poor mill performance, and a poor distribution of the coal from the mills to the specific burners causes elevated temperatures in the regions where the slag samples were extracted. A contributing cause appeared to be poor combustion air mixing and heating, resulting in oxygen stratification and increased temperatures in certain areas. Air preheater plugging was observed and reduces the temperature of the air in the windbox, which leads to poor combustion conditions, resulting in unburned

  18. RECLAMATION OF ALKALINE ASH PILES AND PROTECTION OF THEIR ENVIRONMENT AGAINST DUSTING

    EPA Science Inventory

    The objective of this study was to develop methods to reclaim and stabilize by vegetation fly ash and bottom ash from bituminous and lignite fired power plants. The ash had been transported from the power plant as a slurry and disposed of in ponds. Ashes from these power plants w...

  19. The effect of operation conditions on slagging

    SciTech Connect

    Alekhnovich, A.N.; Bogomolov, V.V.

    1996-12-31

    Operation conditions have an effect on slagging properties of fly ash due to changes of the flue gas temperature and the heat flux. The effect of the same factors for various coal types and boiler zones may differ not only in degree but in opposite sign. In addition, the effect of the factors may vary depending on a combination of other factors. The experimental results confirmed the above idea. It also presents examples of a successful decrease of slagging with the change of operating conditions.

  20. Co-combustion of pellets from Soma lignite and waste dusts of furniture works

    SciTech Connect

    Deveci, N.D.; Yilgin, M.; Pehlivan, D.

    2008-07-01

    In this work, volatiles and char combustion behaviors of the fuel pellets prepared from a low quality lignite and the dusts of furniture works and their various blends were investigated in an experimental fixed bed combustion system through which air flowed by natural convection. Combustion data obtained for varied bed temperatures, mass of pellets, and blend compositions has showed that ignition times of the pellets decreased and volatiles combustion rates tended to increase with the burning temperature. It was concluded that some synergy had existed between lignite and lower ratios of furniture work dusts, which was indicated by a prompt effect on the volatiles combustion rates. Char combustion rates of blend pellets have depended predominantly on the amount of lignite in the blend. The amounts of combustion residues of the pellets were considerably higher than those calculated from individual ash contents of the raw materials and related to lignite ratio in the blends.

  1. Lignite Fuel Enhancement

    SciTech Connect

    Charles Bullinger

    2007-03-31

    This 11th quarterly Technical Progress Report for the Lignite Fuel Enhancement Project summarizes activities from January 1st through March 31st of 2007. It summarizes the completion of the Prototype testing activity and initial full-scale dryer design, Budget Period 2 activity during that time period. The Design Team completed process design and layouts of air, water, and coal systems. Heyl-Patterson completed dryer drawings and has sent RFPs to several fabricators for build and assembly. Several meetings were held with Barr engineers to finalize arrangement of the drying, air jig, and coal handling systems. Honeywell held meetings do discuss the control system logic and hardware location. By the end of March we had processed nearly 300,000 tons of lignite through the dryer. Outage preparation maintenance activities on a coal transfer hopper restricted operation of the dryer in February and March. The Outage began March 17th. We will not dry coal again until early May when the Outage on Unit No.2 completes. The Budget Period 1 (Phase 1) final report was submitted this quarter. Comments were received from NETL and are being reviewed. The Phase 2 Project Management Plan was submitted to NETL in January 2007. This deliverable also included the Financing Plan. An application for R&D 100 award was submitted in February. The project received an award from the Minnesota Professional Engineering Society's Seven Wonders of Engineering Award and Minnesota ACEC Grand Award in January. To further summarize, the focus this quarter has been on finalizing commercial design and the layout of four dryers behind each Unit. The modification to the coal handling facilities at Coal Creek and incorporation of air jigs to further beneficiate the segregated material the dryers will reject 20 to 30 % of the mercury and sulfur is segregated however this modification will recover the carbon in that stream.

  2. Drying of Beulah Zap lignite

    SciTech Connect

    Vorres, K.S.; Molenda, D. ); Dang, Y.; Malhotra, V.M. . Dept. of Physics)

    1991-01-01

    Recent results on the kinetics of water's desorption from Beulah-Zap lignite coal, as determined by thermogravimetric analysis (TGA) and the differential scanning calorimetry (DSC) technique were reported. The kinetic analysis of DSC was further complimented by determining the mechanism of air drying of lignite coal with the help of an in-situ Desorption Kinetics via Fourier transform infrared (ISDK-FTIR) technique. 17 refs., 5 figs., 1 tab.

  3. Fly Ash Amendments Catalyze Soil Carbon Sequestration

    SciTech Connect

    Amonette, James E.; Kim, Jungbae; Russell, Colleen K.; Palumbo, A. V.; Daniels, William L.

    2003-09-15

    We tested the effects of four alkaline fly ashes {Class C (sub-bituminous), Class F (bituminous), Class F [bituminous with flue-gas desulfurization (FGD) products], and Class F (lignitic)} on a reaction that simulates the enzyme-mediated formation of humic materials in soils. The presence of FGD products completely halted the reaction, and the bituminous ash showed no benefit over an ash-free control. The sub-bituminous and lignitic fly ashes, however, increased the amount of polymer formed by several-fold. The strong synergetic effect of these ashes when enzyme is present apparently arises from the combined effects of metal oxide co-oxidation (Fe and Mn oxides), alkaline pH, and physical stabilization of the enzyme (porous silica cenospheres).

  4. Crystallization of synthetic coal-petcoke slag mixtures simulating those encountered in entrained bed slagging gasifiers

    SciTech Connect

    Jinichiro Nakano; Seetharaman Sridhar; Tyler Moss; James Bennett; Kyei-Sing Kwong

    2009-09-15

    Commercial entrained bed slagging gasifiers use a carbon feedstock of coal, petcoke, or combinations of them to produce CO and H{sub 2}. These carbon sources contain mineral impurities that liquefy during gasification and flow down the gasification sidewall, interacting with the refractory linear and solidifying in the cooler zones of the gasifier. Proper slag flow is critical to good gasifier operation. A hot-stage confocal scanning laser microscope (CSLM) was used to analyze the kinetic behavior of slag crystallization for a range of synthetic coal-petcoke mixtures. On the basis of the observed precipitation during cool down studies in the 1200-1700{sup o}C temperature range, a time-temperature-transformation (TTT) diagram was created. The crystallization studies were conducted with a CO/CO{sub 2} (=1.8) corresponding to a gasification PO{sub 2} of approximately 10-8 atm at 1500{sup o}C. Ash chemistries were chosen such that they correspond to coal-petcoke feedstock mixtures with coal ash amounts of 0, 10, 30, 50, 70, and 100% (by weight), with the balance being petcoke ash. The TTT diagram exhibited two crystallization areas, one above and one below 1350{sup o}C. At the nose of the higher temperature curves, karelianite (V{sub 2}O{sub 3}) crystallization occurred and was fastest for a 30% coal-petcoke ash mixture. The second nose was located below 1350{sup o}C and had spinel-type phases that formed at 1200{sup o}C, in which preferred atomic occupation at the octahedral and tetrahedral sites varied depending upon the ash composition. At 1200{sup o}C, an Al-rich spinel formed for 100% coal slag and a Fe-rich spinel formed in petcoke-enriched slags. The addition of petcoke ash to coal ash promoted crystallization in the slag, with additional crystalline phases, such as V-rich spinel, forming at the lower temperatures. These phases were not predicted using commercially available databases. 30 refs., 18 figs.

  5. Fly ash quality and utilization

    SciTech Connect

    Barta, L.E.; Lachner, L.; Wenzel, G.B.; Beer, M.J.

    1995-12-01

    The quality of fly ash is of considerable importance to fly ash utilizers. The fly ash puzzolanic activity is one of the most important properties that determines the role of fly ash as a binding agent in the cementing process. The puzzolanic activity, however is a function of fly ash particle size and chemical composition. These parameters are closely related to the process of fly ash formation in pulverized coal fired furnaces. In turn, it is essential to understand the transformation of mineral matter during coal combustion. Due to the particle-to-particle variation of coal properties and the random coalescence of mineral particles, the properties of fly ash particles e.g. size, SiO{sub 2} content, viscosity can change considerably from particle to particle. These variations can be described by the use of the probability theory. Since the mean values of these randomly changing parameters are not sufficient to describe the behavior of individual fly ash particles during the formation of concrete, therefore it is necessary to investigate the distribution of these variables. Examples of these variations were examined by the Computer Controlled Scanning Electron Microscopy (CCSEM) for particle size and chemical composition for Texas lignite and Eagel Butte mineral matter and fly ash. The effect of combustion on the variations of these properties for both the fly ash and mineral matter were studied by using a laminar flow reactor. It is shown in our paper, that there are significant variations (about 40-50% around the mean values) of the above-listed properties for both coal samples. By comparing the particle size and chemical composition distributions of the mineral matter and fly ash, it was possible to conclude that for the Texas lignite mineral matter, the combustion did not effect significantly the distribution of these properties, however, for the Eagel Butte coal the combustion had a major impact on these mineral matter parameters.

  6. Interactions of Refractory Materials with Molten Gasifier Slags

    SciTech Connect

    Nakano, Jinichiro; Sridhar, Seetharaman; Bennett, James; Kwong, Kyei-Sing; Moss, Tyler

    2011-01-01

    The current study focuses on the analysis of sessile-drop interfacial reactions between two synthetic slags (based on average ash chemistries of coal and petcoke feedstock) and two refractory materials (90 wt% Cr{sub 2}O{sub 3}–10 wt% Al{sub 2}O{sub 3} and 100 wt% Al{sub 2}O{sub 3}), using a Confocal Scanning Laser Microscope (CSLM). Ground slag samples (less than 325 mesh) were placed at specific microstructure locations on refractory substrates and heated to 1500 °C in an atmosphere of CO/CO{sub 2} gas mixture (volume ratio = 1.8), using a gold-image heating chamber. Cross-sections of the slag/refractory interface indicated unique slag penetration into preferred areas of the refractory and grain dissolution into the slag which promoted spalling of the refractory. Initially, the slag attacked both grain boundaries and fine microstructure areas, freeing alumina grains into the slag. The formation of VO{sub x}-based crystalline material in the petcoke slag was found to alter the liquid composition. Chemical spalling of Cr-containing crystal layer also facilitated degradation of the refractory.

  7. Interactions of Refractory Materials with Molten Gasifier Slags

    SciTech Connect

    Nakano, Jimichiro; Sridhar, Seetharaman; Kwong, Kye-Sing; Bennett, James; Moss, Tyler

    2011-04-01

    The current study focuses on the analysis of sessile-drop interfacial reactions between two synthetic slags (based on average ash chemistries of coal and petcoke feedstock) and two refractory materials (90 wt% Cr{sub 2}O{sub 3}–10 wt% Al{sub 2}O{sub 3} and 100 wt% Al{sub 2}O{sub 3}), using a Confocal Scanning Laser Microscope (CSLM). Ground slag samples (less than 325 mesh) were placed at specific microstructure locations on refractory substrates and heated to 1500 °C in an atmosphere of CO/CO{sub 2} gas mixture (volume ratio = 1.8), using a gold-image heating chamber. Cross-sections of the slag/refractory interface indicated unique slag penetration into preferred areas of the refractory and grain dissolution into the slag which promoted spalling of the refractory. Initially, the slag attacked both grain boundaries and fine microstructure areas, freeing alumina grains into the slag. The formation of VO{sub x}-based crystalline material in the petcoke slag was found to alter the liquid composition. Chemical spalling of Cr-containing crystal layer also facilitated degradation of the refractory.

  8. Lignite Fuel Enhancement

    SciTech Connect

    Charles Bullinger

    2005-10-03

    The Design Team continues to conference this quarter albeit not as often. Primary focus this quarter is the continued procurement of material, receiving, and construction/installation. Phase 1 extension recommendation, and subsequent new project estimate. Forms 424 and 4600 were submitted to Ms. Zysk. The NETL technology team subsequently agreed that the increase is justified and made their recommendation to DOE HQ. All major mechanical equipment was delivered this quarter. Three hot water in-bed coils are all that remains for delivery. Two of the five are installed above the dryer air distribution bed. The dryer, baghouse, bucket elevator, control room, exhaust fan, process ductwork, and piping have all been installed. The mezzanine level over the inlet ductwork for access to the dryer was installed. Instrumentation was delivered and locations were identified. Cable is being pulled and connections made from the Control Room to the Motor Control Center. ''Emergency Stop'' equipment logic conditions were discussed and finalized. The functional description was competed and reviewed with Honeywell Controls. Piping & Instrument diagrams are completed. Some electrical schematics have been delivered for equipment south of Q-line. Dry & Wet coal conveyors are not completed. The exhaust chimney was installed. An Open House and ribbon cutting took place on August 9th. GRE project manager gave a presentation of the technology. Joe Strakey, NETL, also spoke. The Open House was attended by Governor Hoevon and Senator Conrad who also spoke about Clean Coal and helped kick-off Blue Flint ethanol and a potential Liquefaction plant. The deign team met the following day to discuss test plan and progress update. Headwaters Energy Incorporated also attended the Open House. A meeting was conducted with them to begin planning for the marketing and finalize our memorandum of understanding. Headwaters still plans to contact all US lignite plants and all bituminous plants who have

  9. Quantitative evaluation of minerals in lignites and intraseam sediments from the Achlada Basin, Northern Greece

    SciTech Connect

    Nikolaos Koukouzas; Colin R. Ward; Dimitra Papanikolaou; Zhongsheng Li

    2009-04-15

    Seven core samples (five lignite samples and two intraseam nonlignite rock samples) from the Achlada open-cut mine in northern Greece were characterized by X-ray diffraction (XRD) and X-ray fluorescence (XRF) techniques. Quantitative evaluation of the mineral phases in each sample was made from the powder X-ray diffractograms using Siroquant commercial interpretation software, which is based on Rietveld principles. The main minerals in the low-temperature ash (LTA) ash of the lignites are kaolinite and illite, with bassanite and quartz in minor proportions. The nonlignite rock samples mainly consist of illite, mica (2M1), and kaolinite (poorly ordered), along with quartz, chlorite (ferroan), feldspar (albite), rutile, and dolomite. Oriented-aggregate XRD study further shows the presence of smectite, and interstratified illite/smectite (I/S), in the clay fractions of the lignite and rock samples, with the mineral matter of the lignites being richer in kaolinite, smectite, and I/S than in mineral matter of the nonlignite materials. The differences in mineralogy between the lignite and the rock materials probably reflect selective concentration of minerals in the original peat during deposition, combined with authigenic precipitation of minerals such as kaolinite in the peat deposit. Inferred chemical analyses derived from the XRD data show reasonably good correlations with chemical data obtained by direct ash analysis, especially if the smectite and I/S are taken into account. This provides a link between mineralogical and chemical studies that may be valuable in evaluating the behavior of the lignite under different utilization conditions. 27 refs., 4 figs., 6 tabs.

  10. Cofiring lignite with hazelnut shell and cotton residue in a pilot-scale fluidized bed combustor

    SciTech Connect

    Zuhal Gogebakan; Nevin Selcuk

    2008-05-15

    In this study, cofiring of high ash and sulfur content lignite with hazelnut shell and cotton residue was investigated in 0.3 MWt METU Atmospheric Bubbling Fluidized Bed Combustion (ABFBC) Test Rig in terms of combustion and emission performance of different fuel blends. The results reveal that cofiring of hazelnut shell and cotton residue with lignite increases the combustion efficiency and freeboard temperatures compared to those of lignite firing with limestone addition only. CO{sub 2} emission is not found sensitive to increase in hazelnut shell and cotton residue share in fuel blend. Cofiring lowers SO{sub 2} emissions considerably. Cofiring of hazelnut shell reduces NO and N{sub 2}O emissions; on the contrary, cofiring cotton residue results in higher NO and N{sub 2}O emissions. Higher share of biomass in the fuel blend results in coarser cyclone ash particles. Hazelnut shell and cotton residue can be cofired with high ash and sulfur-containing lignite without operational problems. 32 refs., 12 figs., 11 tabs.

  11. Lignite Fuel Enhancement

    SciTech Connect

    Charles Bullinger

    2006-04-03

    This 7th quarterly Technical Progress Report for the Lignite Fuel Enhancement Project summarizes activities from January 1st through March 31st of 2006. It also summarizes the subsequent purchasing activity, dryer/process construction, and testing. The Design Team began conferencing again as construction completed and the testing program began. Primary focus this quarter was construction/installation completion. Phase 1 extension recommendation, and subsequent new project estimate, Forms 424 and 4600 were accepted by DOE headquarters. DOE will complete the application and amended contract. All major mechanical equipment was run, checked out, and tested this quarter. All water, air, and coal flow loops were run and tested. The system was run on January 30th, shut down to adjust equipment timing in the control system on the 31st, and run to 75 ton//hour on February 1st. It ran for seven to eight hours per day until March 20th when ''pairs'' testing ( 24 hour running) began. ''Pairs'' involves comparative testing of unit performance with seven ''wet'' pulverizers versus six ''wet'' and one ''dry''. During the interim, more operators were brought up to speed on system operation and control was shifted to the main Unit No.2 Control Room. The system is run now from the Unit control board operator and an equipment operator checks the system during regular rounds or when an alarm needs verification. The flawless start-up is unprecedented in the industry and credit should be made to the diligence and tenacity of Coal Creek maintenance/checkout staff. Great River Energy and Headwaters did not meet to discuss the Commercialization Plan this quarter. The next meeting is pending data from the drying system. Discussions with Basin Electric, Otter Tail, and Dairyland continue and confidentiality secured as we promote dryers in their stations. Lighting and fire protection were completed in January. Invoices No.12 through No.20 are completed and forwarded following preliminary

  12. Thermal exploitation of wastes with lignite for energy production.

    PubMed

    Grammelis, Panagiotis; Kakaras, Emmanuel; Skodras, George

    2003-11-01

    The thermal exploitation of wastewood with Greek lignite was investigated by performing tests in a laboratory-scale fluidized bed reactor, a 1-MW(th) semi-industrial circulating fluidized bed combustor, and an industrial boiler. Blends of natural wood, demolition wood, railroad sleepers, medium-density fiberboard residues, and power poles with lignite were used, and the co-combustion efficiency and the effect of wastewood addition on the emitted pollutants were investigated. Carbon monoxide, sulfur dioxide, and oxides of nitrogen emissions were continuously monitored, and, during the industrial-scale tests, the toxic emissions (polychlorinated dibenzodioxins and dibenzofurans and heavy metals) were determined. Ash samples were analyzed for heavy metals in an inductively coupled plasma-atomic emission spectroscopy spectrophotometer. Problems were observed during the preparation of wastewood, because species embedded with different compounds, such as railway sleepers and demolition wood, were not easily treated. All wastewood blends were proven good fuels; co-combustion proceeded smoothly and homogeneous temperature and pressure profiles were obtained. Although some fluctuations were observed, low emissions of gaseous pollutants were obtained for all fuel blends. The metal element emissions (in the flue gases and the solid residues) were lower than the legislative limits. Therefore, wastewood co-combustion with lignite can be realized, provided that the fuel handling and preparation can be practically performed in large-scale installations. PMID:14649749

  13. Effect of Coal Properties and Operation Conditions on Flow Behavior of Coal Slag in Entrained Flow Gasifiers: A Brief Review

    SciTech Connect

    Wang,Ping; Massoudi, Mehrdad

    2011-01-01

    Integrated gasification combined cycle (IGCC) is a potentially promising clean technology with an inherent advantage of low emissions, since the process removes contaminants before combustion instead of from flue gas after combustion, as in a conventional coal steam plant. In addition, IGCC has potential for cost-effective carbon dioxide capture. Availability and high capital costs are the main challenges to making IGCC technology more competitive and fully commercial. Experiences from demonstrated IGCC plants show that, in the gasification system, low availability is largely due to slag buildup in the gasifier and fouling in the syngas cooler downstream of the gasification system. In the entrained flow gasifiers used in IGCC plants, the majority of mineral matter transforms to liquid slag on the wall of the gasifier and flows out the bottom. However, a small fraction of the mineral matter (as fly ash) is entrained with the raw syngas out of the gasifier to downstream processing. This molten/sticky fly ash could cause fouling of the syngas cooler. Therefore, it is preferable to minimize the quantity of fly ash and maximize slag. In addition, the hot raw syngas is cooled to convert any entrained molten fly slag to hardened solid fly ash prior to entering the syngas cooler. To improve gasification availability through better design and operation of the gasification process, better understanding of slag behavior and characteristics of the slagging process are needed. Slagging behavior is affected by char/ash properties, gas compositions in the gasifier, the gasifier wall structure, fluid dynamics, and plant operating conditions (mainly temperature and oxygen/carbon ratio). The viscosity of the slag is used to characterize the behavior of the slag flow and is the dominating factor to determine the probability that ash particles will stick. Slag viscosity strongly depends on the temperature and chemical composition of the slag. Because coal has varying ash content and

  14. A Brief Review of Viscosity Models for Slag in Coal Gasification

    SciTech Connect

    Massoudi, Mehrdad; Wang, Ping

    2011-11-01

    Many researchers have defined the phenomenon of 'slagging' as the deposition of ash in the radiative section of a boiler, while 'fouling' refers to the deposition of ash in the convective-pass region. Among the important parameters affecting ash deposition that need to be studied are ash chemistry, its transport, deposit growth, and strength development; removability of the ash deposit; heat transfer mechanisms; and the mode of operation for boilers. The heat transfer at the walls of a combustor depends on many parameters including ash deposition. This depends on the processes or parameters controlling the impact efficiency and the sticking efficiency. For a slagging combustor or furnace, however, the temperatures are so high that much of the coal particles are melted and the molten layer, in turn, captures more particles as it flows. The main problems with ash deposition are reduced heat transfer in the boiler and corrosion of the tubes. Common ways of dealing with these issues are soot blowing and wall blowing on a routine basis; however, unexpected or uncontrolled depositions can also complicate the situation, and there are always locations inaccessible to the use of such techniques. Studies have indicated that slag viscosity must be within a certain range of temperatures for tapping and the membrane wall to be accessible, for example, between 1300 C and 1500 C, the viscosity is approximately 25 Pa {center_dot} s. As the operating temperature decreases, the slag cools and solid crystals begin to form. In such cases the slag should be regarded as a non-Newtonian suspension, consisting of liquid silicate and crystals. A better understanding of the rheological properties of the slag, such as yield stress and shear-thinning, are critical in determining the optimum operating conditions. To develop an accurate heat transfer model in any type of coal combustion or gasification process, the heat transfer and to some extent the rheological properties of ash and slag

  15. UTILIZATION OF LIGHTWEIGHT MATERIALS MADE FROM COAL GASIFICATION SLAGS

    SciTech Connect

    Unknown

    2000-04-24

    The integrated-gasification combined-cycle (IGCC) process is an emerging technology that utilizes coal for power generation and production of chemical feedstocks. However, the process generates large amounts of solid waste, consisting of vitrified ash (slag) and some unconverted carbon. In previous projects, Praxis investigated the utilization of ''as-generated'' slags for a wide variety of applications in road construction, cement and concrete production, agricultural applications, and as a landfill material. From these studies, we found that it would be extremely difficult for ''as-generated'' slag to find large-scale acceptance in the marketplace even at no cost because the materials it could replace were abundantly available at very low cost. It was further determined that the unconverted carbon, or char, in the slag is detrimental to its utilization as sand or fine aggregate. It became apparent that a more promising approach would be to develop a variety of value-added products from slag that meet specific industry requirements. This approach was made feasible by the discovery that slag undergoes expansion and forms a lightweight material when subjected to controlled heating in a kiln at temperatures between 1400 and 1700 F. These results confirmed the potential for using expanded slag as a substitute for conventional lightweight aggregates (LWA). The technology to produce lightweight and ultra-lightweight aggregates (ULWA) from slag was subsequently developed by Praxis with funding from the Electric Power Research Institute (EPRI), Illinois Clean Coal Institute (ICCI), and internal resources. The major objectives of the subject project are to demonstrate the technical and economic viability of commercial production of LWA and ULWA from slag and to test the suitability of these aggregates for, various applications. The project goals are to be accomplished in two phases Phase I, comprising the production of LWA and ULWA from slag at the large pilot scale, and

  16. UTILIZATION OF LIGHTWEIGHT MATERIALS MADE FROM COAL GASIFICATION SLAGS

    SciTech Connect

    1999-03-29

    The integrated-gasification combined-cycle (IGCC) process is an emerging technology that utilizes coal for power generation and production of chemical feedstocks. However, the process generates large amounts of solid waste, consisting of vitrified ash (slag) and some unconverted carbon. In previous projects, Praxis investigated the utilization of ''as-generated'' slags for a wide variety of applications in road construction, cement and concrete production, agricultural applications, and as a landfill material. From these studies, we found that it would be extremely difficult for ''as-generated'' slag to find large-scale acceptance in the marketplace even at no cost because the materials it could replace were abundantly available at very low cost. It was further determined that the unconverted carbon, or char, in the slag is detrimental to its utilization as sand or fine aggregate. It became apparent that a more promising approach would be to develop a variety of value-added products from slag that meet specific industry requirements. This approach was made feasible by the discovery that slag undergoes expansion and forms a lightweight material when subjected to controlled heating in a kiln at temperatures between 1400 and 1700 F. These results confirmed the potential for using expanded slag as a substitute for conventional lightweight aggregates (LWA). The technology to produce lightweight and ultra-lightweight aggregates (ULWA) from slag was subsequently developed by Praxis with funding from the Electric Power Research Institute (EPRI), Illinois Clean Coal Institute (ICCI), and internal resources. The major objectives of the subject project are to demonstrate the technical and economic viability of commercial production of LWA and ULWA from slag and to test the suitability of these aggregates for various applications. The project goals are to be accomplished in two phases: Phase I, comprising the production of LWA and ULWA from slag at the large pilot scale, and

  17. Utilization of lightweight materials made from coal gasification slags

    SciTech Connect

    1999-09-30

    The integrated-gasification combined-cycle (IGCC) process is an emerging technology that utilizes coal for power generation and production of chemical feedstocks. However, the process generates large amounts of solid waste, consisting of vitrified ash (slag) and some unconverted carbon. In previous projects, Praxis investigated the utilization of as-generated slags for a wide variety of applications in road construction, cement and concrete production, agricultural applications, and as a landfill material. From these studies, the authors found that it would be extremely difficult for as-generated slag to find large-scale acceptance in the marketplace even at no cost because the materials it could replace were abundantly available at very low cost. It was further determined that the unconverted carbon, or char, in the slag is detrimental to its utilization as sand or fine aggregate. It became apparent that a more promising approach would be to develop a variety of value-added products from slag that meet specific industry requirements. This approach was made feasible by the discovery that slag undergoes expansion and forms a lightweight material when subjected to controlled heating in a kiln at temperatures between 1,400 and 1,700 F. These results confirmed the potential for using expanded slag as a substitute for conventional lightweight aggregates (LWA). The technology to produce lightweight and ultra-lightweight aggregates (ULWA) from slag was subsequently developed by Praxis with funding from the Electric Power Research Institute (EPRI), Illinois Clean Coal Institute (ICCI), and internal resources. The major objectives of the subject project are to demonstrate the technical and economic viability of commercial production of LWA and ULWA from slag and to test the suitability of these aggregates for various applications. The project goals are to be accomplished in two phases: Phase 1, comprising the production of LWA and ULWA from slag at the large pilot scale

  18. Slag characterization and removal using pulse detonation for coal gasification

    SciTech Connect

    Huque, Z.; Mei, D.; Biney, P.O.; Zhou, J.

    1997-06-25

    This report is a preliminary economic analysis of the Sherburne Co. plant North State Power. This analysis is made with the cooperation of Joe Brojberg (senior analysis engineer of NSP) and Steve Bension (Slag and ash specialist, President of Microbeam Technologies Incorporated (MTI) of North Dakota) and Paul Johnson of Diamond Power Speciality.

  19. Atmospheric Fluidized Bed Combustion testing of North Dakota lignite

    SciTech Connect

    Goblirsch, G; Vander Molen, R H; Wilson, K; Hajicek, D

    1980-05-01

    The sulfur retention by the inherent alkali, and added limestone sorbent, perform about the same and are reasonably predictable within a range of about +-10% retention by application of alkali to sulfur ratio. Temperature has a substantial effect on the retention of sulfur by the inherent alkali or limestone. The temperature effect is not yet fully understood but it appears to be different for different coals and operational conditions. The emission of SO/sub 2/ from the fluid bed burning the Beulah lignite sample used for these tests can be controlled to meet or better the current emission standards. The injection of limestone to an alkali-to-sulfur molar ratio of 1.5 to 1, should lower the SO/sub 2/ emissions below the current requirement of 0.6 lb SO/sub 2//10/sup 6/ Btu to 0.4 lb SO/sub 2//10/sup 6/ Btu, a safe 33% below the standard. Agglomeration of bed material, and consequent loss of fluidization quality can be a problem when burning high sodium lignite in a silica bed. There appears, however, to be several ways of controlling the problem including the injection of calcium compounds, and careful control of operating conditions. The heat transfer coefficients measured in the CPC and GFETC tests are comparable to data obtained by other researchers, and agree reasonably well with empirical conditions. The NO/sub x/ emissions measured in all of the tests on Beulah lignite are below the current New Source Performance Standard of 0.5 lb NO/sub 2//10/sup 6/ Btu input. Combustion efficiencies for the Beulah lignite are generally quite high when ash recycle is being used. Efficiencies in the range of 98% to 99%+ have been measured in all tests using this fuel.

  20. Removal of Metallic Iron on Oxide Slags

    NASA Astrophysics Data System (ADS)

    Shannon, George N.; Fruehan, R. J.; Sridhar, Seetharaman

    2009-10-01

    It is possible, in some cases, for ground coal particles to react with gasifier gas during combustion, allowing the ash material in the coal to form phases besides the expected slag phase. One of these phases is metallic iron, because some gasifiers are designed to operate under a reducing atmosphere ({p_{O2}} of approximately 10-4 atm). Metallic iron can become entrained in the gas stream and deposit on, and foul, downstream equipment. To improve the understanding of the reaction between different metallic iron particles and gas, which eventually oxidizes them, and the slag that the resulting oxide dissolves in, the kinetics of iron reaction on slag were predicted using gas-phase mass-transfer limitations for the reaction and were compared with diffusion in the slag; the reaction itself was observed under confocal scanning laser microscopy. The expected rates for iron droplet removal are provided based on the size and effective partial pressure of oxygen, and it is found that decarburization occurs before iron reaction, leading to an extra 30- to 100-second delay for carbon-saturated particles vs pure iron particles. A pure metallic iron particle of 0.5 mg should be removed in about 220 seconds at 1400 °C and in 160 seconds at 1600 °C.

  1. Removal of metallic iron on oxide slags

    SciTech Connect

    Shannon, G.N.; Fruehan, R.J.; Sridhar, S.

    2009-10-15

    It is possible, in some cases, for ground coal particles to react with gasifier gas during combustion, allowing the ash material in the coal to form phases besides the expected slag phase. One of these phases is metallic iron, because some gasifiers are designed to operate under a reducing atmosphere (pO{sub 2}) of approximately 10{sup -4} atm). Metallic iron can become entrained in the gas stream and deposit on, and foul, downstream equipment. To improve the understanding of the reaction between different metallic iron particles and gas, which eventually oxidizes them, and the slag that the resulting oxide dissolves in, the kinetics of iron reaction on slag were predicted using gas-phase mass-transfer limitations for the reaction and were compared with diffusion in the slag; the reaction itself was observed under confocal scanning laser microscopy. The expected rates for iron droplet removal are provided based on the size and effective partial pressure of oxygen, and it is found that decarburization occurs before iron reaction, leading to an extra 30- to 100-second delay for carbon-saturated particles vs pure iron particles. A pure metallic iron particle of 0.5 mg should be removed in about 220 seconds at 1400{sup o}C and in 160 seconds at 1600{sup o}C.

  2. Slag characterization and removal using pulse detonation for coal gasification. Quarterly research report, July 1--September 31, 1996

    SciTech Connect

    Huque, Z.; Mei, D.; Biney, P.O.; Zhou, J.; Ali, M.R.

    1996-10-25

    Boiler slagging and fouling as a result of inorganic impurities in combustion gases being deposited on heat transfer tubes have caused severe problems in coal-fired power plant operation. These problems are fuel, system design, and operating condition dependent. Conventional slag and ash removal methods include the use of in situ blowing or jet-type devices such as air or steam soot blowers and water lances. Pulse detonation technology for the purpose of removing slag and fouling deposits in coal-fired utility power plant boilers offers great potential. The detonation wave technique based on high impact velocity with sufficient energy and thermal shock on the slag deposited on gas contact surfaces offers a convenient, inexpensive, yet efficient and effective way to supplement existing slag removal methods. These detonation waves have been demonstrated experimentally to have exceptionally high shearing capability important to the task of removing slag and fouling deposits. Several tests have been performed with single shot detonation wave at University of Texas at Arlington to remove the slag deposit. To hold the slag deposit samples at the exit of detonation tube, two types of fixture was designed and fabricated. They are axial arrangement and triangular arrangement. The slag deposits from the utility boilers have been used to prepare the slag samples for the test. The experimental results show that the single shot detonation wave is capable of removing the entire slag (types of slag deposited on economizer, and air-heater, i.e., relatively softer slags) and 30% of the reheater slag (which is harder) even at a distance of 6 in. from the exit of a detonation engine tube. Wave strength and slag orientation also have different effects on the chipping off of the slag. The annual report discusses about the results obtained in effectively removing the slag.

  3. Production of cooking briquettes from Maissade (Haiti) lignite. Feasibility study and preliminary plant design

    SciTech Connect

    Hauserman, W.B.; Johnson, M.D.

    1986-03-20

    A laboratory study was done to establish the technical feasibility of producing domestic cooking briquettes to be marketed in Haiti, from the Maissade lignite reserves of that country, which are high in both ash and sulfur and not yet mined. It was found that acceptable briquettes could be made from Maissade char, pyrolized and compacted with a molasses-lime binder and the addition of bagasse to improve strength and burning rate. Molasses, lime and bagasse are all produced in Haiti. Sodium nitrate was added to enhance ignition, and borax as a wetting and release agent. Standard, ''pillow-shaped'' briquettes were successfully produced on a standard, double roll briquetting machine. The recommended process sequence and equipment selection are virtually identical to that used to produce standard US barbecue briquettes from North Dakota lignite. The heating value of the Maissade briquettes is lower due to their high ash level, which may be acceptable if they can be produced at a cost per heating value comparable to wood charcoal, currently used in Haiti. The high sulfur content, mostly in organic form, presents no problem, since it is tied up after combustion as CaSO/sub 4/ by the unusually high calcium content of this lignite. Detailed analyses of Maissade lignite and its mineral components are included, as well as a preliminary plant design and capital cost estimate, for capacities of 10,000 and 50,000 metric tons per year, and for a smaller pilot plant.

  4. Crystallization phenomena in slags

    NASA Astrophysics Data System (ADS)

    Orrling, Carl Folke

    2000-09-01

    The crystallization of the mold slag affects both the heat transfer and the lubrication between the mold and the strand in continuous casting of steel. In order for mold slag design to become an engineering science rather than an empirical exercise, a fundamental understanding of the melting and solidification behavior of a slag must be developed. Thus it is necessary to be able to quantify the phenomena that occur under the thermal conditions that are found in the mold of a continuous caster. The double hot thermocouple technique (DHTT) and the Confocal Laser Scanning Microscope used in this study are two novel techniques for investigating melting and solidification phenomena of transparent slags. Results from these techniques are useful in defining the phenomena that occur when the slag film infiltrates between the mold and the shell of the casting. TTT diagrams were obtained for various slags and indicated that the onset of crystallization is a function of cooling rate and slag chemistry. Crystal morphology was found to be dependent upon the experimental temperature and four different morphologies were classified based upon the degree of melt undercooling. Continuous cooling experiments were carried out to develop CCT diagrams and it was found that the amount and appearance of the crystalline fraction greatly depends on the cooling conditions. The DHTT can also be used to mimic the cooling profile encountered by the slag in the mold of a continuous caster. In this differential cooling mode (DCT), it was found that the details of the cooling rate determine the actual response of the slag to a thermal gradient and small changes can lead to significantly different results. Crystal growth rates were measured and found to be in the range between 0.11 mum/s to 11.73 mum/s depending on temperature and slag chemistry. Alumina particles were found to be effective innoculants in oxide melts reducing the incubation time for the onset of crystallization and also extending

  5. Nonequilibrium Sulfur Capture and Retention in an Air cooled Slagging Coal Combustion.

    SciTech Connect

    Zauderer, B.

    1997-04-14

    Calcium oxide sorbents injected in a slagging combustor react with the sulfur released during coal combustion to form sulfur bearing particles, some of which are deposited on the liquid slag layer on the combustor wall. Since the solubility of sulfur in liquid slag is low, the slag must be drained from the combustor to limit sulfur re-evolution into the gas phase. The objective of this 24 month project is to perform a series of 16 one day tests to determine the factors that control the retention of the sulfur in the slag that is drained from the combustor. The last of the 16 tests planned for this project was completed in the present reporting period. This was the first test in this project that validated one of the primary hypothesis of this project, namely to retain substantial quantities of sulfur in slag requires high slag mass flow rate. Previous attempts to achieve high sulfur retention with artificial slag met limited success. In this, the 16th test, a high, 37%, ash Indian coal was injected into Coal Tech`s 20 MMBtu/hr air cooled, slagging combustor with gypsum, CaSO{sub 4} (2H{sub 2}O). The slag analysis showed that 20% of the sulfur in the gypsum remained in the slag. This is double the highest sulfur concentration in slag measured in numerous test operations with this combustor. While the test results to date have met the objectives of this project, further high slag mass flow rate tests are planned with the Indian coal to optimize sulfur retention in slag.

  6. Coal Ash Behavior in Reducing Environments (CABRE) III Year 6 - Activity 1.10 - Development of a National Center for Hydrogen

    SciTech Connect

    Stanislowski, Joshua; Azenkeng, Alexander; McCollor, Donald; Galbreath, Kevin; Jensen, Robert; Lahr, Brent

    2012-03-31

    The Energy & Environmental Research Center (EERC) has been conducting research on gasification for six decades. One of the objectives of this gasification research has been to maximize carbon conversion and the water–gas shift process for optimal hydrogen production and syngas quality. This research focus and experience were a perfect fit for the National Center for Hydrogen Technology ® (NCHT®) Program at the EERC for improving all aspects of coal gasification, which ultimately aids in the production and purification of hydrogen. A consortia project was developed under the NCHT Program to develop an improved predictive model for ash formation and deposition under the project entitled “Coal Ash Behavior in Reducing Environments (CABRE) III: Development of the CABRE III Model.” The computer-based program is now applicable to the modeling of coal and ash behavior in both entrained-flow and fluidized-bed gasification systems to aid in overall gasification efficiency. This model represents a significant improvement over the CABRE II model and runs on a Microsoft Windows PC platform. The major achievements of the CABRE III model are partitioning of inorganic transformations between various phases for specific gas cleanup equipment; slag property predictions, including standard temperature–viscosity curves and slag flow and thickness; deposition rates in gasification cleanup equipment; provision for composition analysis for all input and output streams across all process equipment, including major elements and trace elements of interest; composition analysis of deposit streams for various deposit zones, including direct condensation on equipment surfaces (Zone A), homogeneous particulate deposition (Zone B), and entrained fly ash deposition (Zone C); and physical removal of ash in cyclones based on D50 cut points. Another new feature of the CABRE III model is a user-friendly interface and detailed reports that are easily exportable into Word documents, Excel

  7. Molten welding slag enthalpies

    SciTech Connect

    Stukalo, V.A.; Neshchimenko, N.Ya.; Batalin, G.I.; Patselii, N.V.; Galinich, V.I.

    1988-05-01

    We measured enthalpies at 1740-19970 K for four multicomponent oxide liquids. The initial materials were special-purity metal oxides, chemically pure manganese oxalate, and calcium fluoride. High-temperature calorimetry has been applied to the enthalpies of slags used in automatic constructional-steel welding. The mean specific heats have been calculated from the temperature dependence of the enthalpies. The enthalpies increase with the basicity in these slags.

  8. Making IGCC slag valuable

    SciTech Connect

    Wicker, K.

    2005-12-01

    All indications are that integrated gasification combined-cycle (IGCC) technology will play a major role in tomorrow's generation industry. But before it does, some by-products of the process must be dealt with, for example unburned carbon that can make IGCC slag worthless. Charah Inc.'s processing system, used at Tampa Electric's Polk Station for years, segregates the slag's constituents by size, producing fuel and building materials. 3 figs.

  9. Analysis of municipal refuse incinerator ashes for asbestos

    SciTech Connect

    Patel-Mandlik, K.J.; Manos, C.G.; Lisk, D.J.

    1988-12-01

    The ash which results from incineration includes bottom ash (slag) and fly ash, the latter being trapped in electrostatic precipitators or fabric filtration systems (baghouses, etc.). These ashes are collected separately or mixed and usually disposed in secure landfills with or without prior recovery of reusable metals. Whereas many published surveys have dealt with the concentrations of heavy metals and toxic organics in such ashes, very little has been reported on the possible presence of asbestos in them. In the work reported here, an analytical survey was conducted of the possible presence of asbestos in 20 such ashes from 18 incinerators in the United States.

  10. Solubilization of Australian lignites by microorganisms

    SciTech Connect

    Catcheside, D.E.A.; Mallett, K.J.; Cox, R.E.

    1988-01-01

    Australia has substantial lignite deposits, particularly in the Latrobe Valley in Victoria where 4.10/sup 10/ tons are accessible with available technologies. The authors have investigated the susceptibility of these coal to solubilization by microorganisms, including species additional to those already identified as active on North American lignites. The data presented here show that acid oxidized lignites from the Latrobe Valley are solubilized by each of seven species of microorganisms previously found to be active on Leonardite and oxidized North American lignites. These are the wood rot fungi: Trametes versicolor, Poria placenta and Phanerochaete chrysosporium, the lignin degrading prokaryote Streptomyces viridosporus and three fungi isolated from lignite in Mississippi: Candida ML-13, Cunninghamelia YML-1 and Penicillium waksmanii.

  11. Trace elements in a Pliocene-Pleistocene lignite profile from the Afsin-Elbistan field, eastern Turkey

    SciTech Connect

    Karayigit, A.I.; Gayer, R.A.

    2000-01-01

    The authors present the results of proximate and ultimate analyses, mineralogical determination, and trace element analysis of a lignite profile from the Afsin-Elbistan field (eastern Turkey). The lignite, which developed during the Pliocene-Pleistocene transition under freshwater lacustrine conditions, contains white gastropod (Planorbidae) shells composed of calcite and a little aragonite. Other identifiable mineral constituents, analyzed by X-ray powder diffraction, include quartz, pyrite, clay minerals, and rare feldspares. Petrographical studies demonstrate the immature nature of these lignites and very low degree of compaction during diagenesis. The mean concentrations of trace elements in the lignite, determined by inductively coupled plasma mass spectrometry (ICP-MS), show relative enrichment in Mo (avg. 20 ppm), W (avg. 15 ppm) and U (avg. 25 ppm) when compared to the global range for most coals, while the others (Ti, p, Sc, Be, Mn, Co, Cu, Zn, Ga, As, Rb, Sr, Zr, Nb, Cs, Ba, Y, Ta, Tl, Pb, Bi, Th, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Yb, Lu) fall within their global ranges. Many of the trace elements show a good correlation with the ash yield, implying an inorganic affinity. However, Mo and Sr show a negative correlation with the ash yield and are thought to be organically associated. A lack of correlation of U with either the ash yield or the coal sulfur content, together with its relative enrichment, suggests secondary mobility of this element.

  12. Behaviour of heavy metals immobilized by co-melting treatment of sewage sludge ash and municipal solid waste incinerator fly ash.

    PubMed

    Lin, Kae-Long; Huang, Wu-Jang; Chen, Kuan-Chung; Chow, Jing-Dong; Chen, His-Jien

    2009-10-01

    This study elucidates the behaviour of heavy metals in slag produced from four different sewage sludge ashes mixed with municipal solid waste incinerator fly ash and then co-melted. Experimental results indicate that sewage sludge ashes consisted of SiO(2), CaO, and Al(2)O(3). Fly ash consisted of CaO, Na(2)O and SO(3). The speciation of sewage sludge ashes indicates that the ashes contained quartz and AlPO(4). The speciation in fly ash consisted of anhydrite, microcline, calcium chloride, sylvite and halite. The leaching behaviours of sewage sludge ashes met the Taiwan Environmental Protection Administration's regulatory standards. The fly ash had high concentrations of Zn and Pb; however, the leaching of these metals was low. The major components of synthetic slags were SiO(2) (33.5-54.0%), CaO (21.4-36.7%), and Al(2)O(3) (8.1-15.7%). The X-ray diffraction patterns of co-melted slags demonstrate that the slags contained significant amounts of glass. Most heavy metals can be fixed in a net-like structure; thus, they can not be extracted easily. The toxicity characteristic leaching procedure (TCLP) leaching concentrations for target metals in all slags met the Taiwan Environmental Protection Administration's regulatory standards. PMID:19470538

  13. Thermal treatment and vitrification of boiler ash from a municipal solid waste incinerator.

    PubMed

    Yang, Y; Xiao, Y; Voncken, J H L; Wilson, N

    2008-06-15

    Boiler ash generated from municipal solid waste (MSW) incinerators is usually classified as hazardous materials and requires special disposal. In the present study, the boiler ash was characterized for the chemical compositions, morphology and microstructure. The thermal chemical behavior during ash heating was investigated with thermal balance. Vitrification of the ash was conducted at a temperature of 1400 degrees C in order to generate a stable silicate slag, and the formed slag was examined with chemical and mineralogical analyses. The effect of vitrification on the leaching characteristics of various elements in the ash was evaluated with acid leaching. The study shows that the boiler ash as a heterogeneous fine powder contains mainly silicate, carbonate, sulfates, chlorides, and residues of organic materials and heavy metal compounds. At elevated temperatures, the boiler ash goes through the initial moisture removal, volatilization, decomposition, sintering, melting, and slag formation. At 1400 degrees C a thin layer of salt melt and a homogeneous glassy slag was formed. The experimental results indicate that leaching values of the vitrified slag are significantly reduced compared to the original boiler ash, and the vitrification could be an interesting alternative for a safer disposal of the boiler ash. Ash compacting, e.g., pelletizing can reduce volatilization and weight loss by about 50%, and would be a good option for the feed preparation before vitrification. PMID:18077086

  14. Lignite pellets and methods of agglomerating or pelletizing

    DOEpatents

    Baker, Albert F.; Blaustein, Eric W.; Deurbrouck, Albert W.; Garvin, John P.; McKeever, Robert E.

    1981-01-01

    The specification discloses lignite pellets which are relatively hard, dust resistant, of generally uniform size and free from spontaneous ignition and general degradation. Also disclosed are methods for making such pellets which involve crushing as mined lignite, mixing said lignite with a binder such as asphalt, forming the lignite binder mixture into pellets, and drying the pellets.

  15. Paleocene-eocene lignite beds of southwest Alabama: Parasequence beds in highstand systems tracts

    SciTech Connect

    Mancini, E.A.; Tew, B.H. ); Carroll, R.E. )

    1993-09-01

    In southwest Alabama, lignite beds are present in at least four stratigraphic intervals that span approximately 8 m.y. of geologic time. Lignite is found in the Paleocene Oak Hill Member and Coal Bluff Member of the Naheola Formation of the Midway Group and the Paleocene Tuscahoma Sand and the Eocene Hatchetigbee Formation of the Wilcox Group. Lignite beds range in thickness from 0.5 to 11 ft and consist of 32-53% moisture, 13-39% volatile matter, 4-36% fixed carbon, and 5-51% ash. These Paleocene and Eocene lignite beds occur as parasequence deposits in highstand systems tracts of four distinct third-order depositional sequences. The lignite beds are interpreted as strata within highstand systems tract parasequences that occur in mud-dominated regressive intervals. Lignite beds were deposited in coastal marsh and low-lying swamp environments as part of deltaic systems that prograded into southwestern Alabama from the west. As sediment was progressively delivered into the basin from these deltas, the effects of relative sea level rise during an individual cycle were overwhelmed, producing a net loss of accommodation and concomitant overall basinward progradation of the shoreline (regression). Small-scale fluctuations in water depth resulting from the interaction of eustasy, sediment yield, and subsidence led to cyclical flooding of the low-lying coastal marshes and swamps followed by periods of progradational and regression. Highstand systems tract deposition within a particular depositional sequence culminated with a relative sea level fall that resulted in a lowering of base level and an abrupt basinward shift in coastal onlap. Following sea level fall and the subsequent accumulation of the lowstand deposits, significant relative sea level rise resulted in the marine inundation of the area previously occupied by coastal marshes and swamps and deposition of the transgressive systems tract of the overlying sequence.

  16. Evaluation of PRB subbituminous coal--petroleum coke blending on fouling and slagging

    SciTech Connect

    Galbreath, K.C.; Zygarlicke, J.; Toman, D.L.

    1999-07-01

    The effects of blending petroleum shot coke with two Powder River Basin (PRB) subbituminous coals on ash fouling and slagging were evaluated using two laboratory-scale (fuel feed rates of {approx} 6 g/hr and 2 kg/hr) combustion systems. Deposits from coal-petroleum coke blends of 100:0, 90:10, and 80:20 on a coal:coke weight basis were generated under fouling and slagging conditions. Measurements of fouling deposit growth rates and slag deposit compressive strengths indicate that petroleum coke blending with PRB subbituminous coal impedes the rate of ash deposition but promotes slag deposit strength. A vanadium K-edge x-ray absorption fine structure spectroscopy analysis of a fly ash sample indicates that vanadium, generally the dominant inorganic component of petroleum coke, is present in a pentavalent oxidation state (V{sup 5+}), most likely as a metal vanadate compound. Sulfur analysis of combustion flue gases and fly ashes indicate that petroleum coke blending promotes the conversion of fuel sulfur to inorganic sulfate (SO{sub 4}) compounds in the fly ash. V{sup 5+} catalysis of SO{sub 2}(g) oxidation followed by SO{sub 3}(g) reaction with lime (CaO) to form anhydrite (CaSO{sub 4}) is the dominant ash sulfation mechanism.

  17. Ash melting system and reuse of products by arc processing

    SciTech Connect

    Kinto, Koichiro

    1996-12-31

    To form a resource recycling society and to extend the life of landfill sites, the melting process of municipal waste incinerator residue is estimated to be the best way of recycling products as resources. This paper presents a recent application of an arc melting system and utilization of its products. Five plants are now operating satisfactorily and two are under construction. Total capacity of these corresponds to the largest in the world. The slag and metal from these plants are under trial utilization. Pb and Zn recovery methods from the condensate have been developed. The arc melting process of fly ash mixed with bottom ash has been certified and the mechanical properties and chemical stability of fly ash mixed slag was found to be equivalent to bottom ash slag, both fulfilling the regulations.

  18. Paleocene lignite deposits of southwest Alabama

    SciTech Connect

    Mancini, E.A.

    1984-04-01

    In southwest Alabama, lignite having economic potential occurs in the Oak Hill Member of the Naheola Formation. This middle Paleocene lignite generally consists of a single bed of 1-14 ft (0.5-4 m) in thickness and is the most extensive lignite in the southwest Alabama region. The Oak Hill lignite deposit accumulated in lower delta plain coastal marshes in interchannel areas behind a barrier system. The source area for the deltaic sediments was probably to the west and/or northwest of Choctaw County, Alabama. The lignite occurs in a clay-dominated sequence. Oak Hill interdistributary bay ripple-laminated clays are interbedded with ripple-laminated, crevasse splay sands generally less than 15 ft (5 m) thick. The glauconitic sands of the overlying Coal Bluff Marl Member of the Naheola Formation represent times of marine encroachment into the interchannel basin area. Lignite having subeconomic value at present occurs in the upper part of the Tuscahoma Sand. This upper Paleocene lignite is irregular in its outcrop pattern and apparently is not represented over extensive areas. It is locally persistent with one or more beds less than 3 ft (1 m) thick. The Tuscahoma may contain up to 6 lignite seams that may exceed a total thickness of 5 ft (1.5 m). These lignite beds were deposited in lower delta-plain coastal marshes adjacent to high constructive deltaic bar finger sands. Tuscahoma marsh clays are interbedded with ripple-laminated and cross-bedded bar finger sands. The Tuscahoma Sand is overlain by the Bashi Marl Member of the Hatchetigbee Formation. The Bashi contains a diverse lower Eocene marine fossil assemblage.

  19. Paleocene lignite deposits of southwest Alabama

    SciTech Connect

    Mancini, E.A.

    1984-04-01

    In southwest Alabama, lignite having economic potential occurs in the Oak Hill Member of the Naheola Formation. This middle Paleocene lignite generally consists of a single bed of 1-14 ft (0.5-4 m) in thickness and is the most extensive lignite in the southwest Alabama region. The Oak Hill lignite deposit accumulated in lower delta plain coastal marshes in interchannel areas behind a barrier system. The source area for the deltaic sediments was probably to the west and/or northwest of Choctaw County, Alabama. The lignite occurs in a clay-dominated sequence. Oak Hill interdistributary bay ripple-laminated clays are interbedded with ripple-laminated, crevasse splay sands generally less than 15 ft (5 m) thick. The glauconitic sands of the overlying Coal Bluff Marl Member of the Naheola Formation represent times of marine encroachment into the interchannel basin area. Lignite haing subeconomic value at present occurs in the upper part of the Tuscahoma Sand. This upper Paleocene lignite is irregular in its outcrop pattern and apparently is not represented over extensive areas. It is locally persistent with one or more beds less than 3 ft (1 m) thick. The Tuscahoma may contain up to 6 lignite seams that may exceed a total thickness of 5 ft (1.5 m). These lignite beds were deposited in lower delta-plain coastal marshes adjacent to high constructive deltaic bar finger sands. Tuscahoma marsh clays are interbedded with ripple-laminated and cross-bedded bar finger sands. The Tuscahoma Sand is overlain by the Bashi Marl Member of the Hatchetigbee Formation. The Bashi contains a diverse lower Eocene marine fossil assemblage.

  20. Microbial desulphurization of Turkish lignites by White Rot Fungi

    SciTech Connect

    Pinar Aytar; Mesut Sam; Ahmet Cabuk

    2008-03-15

    Biodesulphurization experiments were carried out with Tuncbilek lignite, characterized by high sulfur content (2.59%) by using Trametes versicolor ATCC 200801 and Phanerochaete chrysosporium ME 446. At fungal biomass studies, the effects of various parameters on fungal desulphurization of coals such as pH, temperature, pulp density, incubation time, and sterilization were investigated for both microorganisms. The maximum desulphurization (40%) was observed after 6 days of incubation at 35{sup o}C for T. versicolor. The optimum pH was measured at 6, and the agitation rate was fixed at 125 rpm. The pulp density was found as 5% (w/v) for the high extent of desulphurization. Also, calorific value did not change during this experiment. However, the ash and metal contents of coal were eliminated. 30 refs., 6 figs., 2 tabs.

  1. JV Task - 129 Advanced Conversion Test - Bulgarian Lignite

    SciTech Connect

    Michael Swanson; Everett Sondreal; Daniel Laudal; Douglas Hajicek; Ann Henderson; Brandon Pavlish

    2009-03-27

    The objectives of this Energy & Environmental Research Center (EERC) project were to evaluate Bulgarian lignite performance under both fluid-bed combustion and gasification conditions and provide a recommendation as to which technology would be the most technically feasible for the particular feedstock and also identify any potential operating issues (such as bed agglomeration, etc.) that may limit the applicability of a potential coal conversion technology. Gasification tests were run at the EERC in the 100-400-kg/hr transport reactor development unit (TRDU) on a 50-tonne sample of lignite supplied by the Bulgarian Lignite Power Project. The quality of the test sample was inferior to any coal previously tested in this unit, containing 50% ash at 26.7% moisture and having a higher heating value of 5043 kJ/kg after partial drying in preparation for testing. The tentative conclusion reached on the basis of tests in the TRDU is that oxygen-blown gasification of this high-ash Bulgarian lignite sample using the Kellogg, Brown, and Root (KBR) transport gasifier technology would not provide a syngas suitable for directly firing a gas turbine. After correcting for test conditions specific to the pilot-scale TRDU, including an unavoidably high heat loss and nitrogen dilution by transport air, the best-case heating value for oxygen-blown operation was estimated to be 3316 kJ/m{sup 3} for a commercial KRB transport gasifier. This heating value is about 80% of the minimum required for firing a gas turbine. Removing 50% of the carbon dioxide from the syngas would increase the heating value to 4583 kJ/m{sup 3}, i.e., to about 110% of the minimum requirement, and 95% removal would provide a heating value of 7080 kJ/m{sup 3}. Supplemental firing of natural gas would also allow the integrated gasification combined cycle (IGCC) technology to be utilized without having to remove CO{sub 2}. If removal of all nitrogen from the input gas streams such as the coal transport air were

  2. Bioprocessing of lignite coals using reductive microorganisms

    SciTech Connect

    Crawford, D.L.

    1992-03-29

    In order to convert lignite coals into liquid fuels, gases or chemical feedstock, the macromolecular structure of the coal must be broken down into low molecular weight fractions prior to further modification. Our research focused on this aspect of coal bioprocessing. We isolated, characterized and studied the lignite coal-depolymerizing organisms Streptomyces viridosporus T7A, Pseudomonas sp. DLC-62, unidentified bacterial strain DLC-BB2 and Gram-positive Bacillus megaterium strain DLC-21. In this research we showed that these bacteria are able to solubilize and depolymerize lignite coals using a combination of biological mechanisms including the excretion of coal solublizing basic chemical metabolites and extracellular coal depolymerizing enzymes.

  3. Interfaces Between Coke, Slag, and Metal in the Tuyere Level of a Blast Furnace

    NASA Astrophysics Data System (ADS)

    Li, Kejiang; Zhang, Jianliang; Liu, Zhengjian; Barati, Mansoor; Zhong, Jianbo; Wei, Mengfang; Wang, Guangwei; Jiao, Kexin; Yang, Tianjun

    2015-04-01

    An in-depth understanding about the reactions in the high-temperature zone of a blast furnace is significant to optimize both the current and future blast furnace process. The interfaces between coke, slag, and metal were observed using scanning electronic microscope with samples obtained from the tuyere level of a blast furnace. Two types of slag phases were identified, one originating from coke ash and the other from the bosh slag. Slag formed by coke ash was seen to cover the coke surface, which may hinder the reaction of coke with both gas and liquid iron. The reduction of FeO from the bosh slag (originated from the primary slag) occurs in the coke/slag interface with the reduced iron forming a metal layer surrounding the coke surface. The reduction of SiO2 occurs both in and outside the coke, and the reduced silicon reacts with iron to form iron silicide if the two species come into contact. Further study is proposed based on the results of this study.

  4. Hydration characteristics and environmental friendly performance of a cementitious material composed of calcium silicate slag.

    PubMed

    Zhang, Na; Li, Hongxu; Zhao, Yazhao; Liu, Xiaoming

    2016-04-01

    Calcium silicate slag is an alkali leaching waste generated during the process of extracting Al2O3 from high-alumina fly ash. In this research, a cementitious material composed of calcium silicate slag was developed, and its mechanical and physical properties, hydration characteristics and environmental friendly performance were investigated. The results show that an optimal design for the cementitious material composed of calcium silicate slag was determined by the specimen CFSC7 containing 30% calcium silicate slag, 5% high-alumina fly ash, 24% blast furnace slag, 35% clinker and 6% FGD gypsum. This blended system yields excellent physical and mechanical properties, confirming the usefulness of CFSC7. The hydration products of CFSC7 are mostly amorphous C-A-S-H gel, rod-like ettringite and hexagonal-sheet Ca(OH)2 with small amount of zeolite-like minerals such as CaAl2Si2O8·4H2O and Na2Al2Si2O8·H2O. As the predominant hydration products, rod-like ettringite and amorphous C-A-S-H gel play a positive role in promoting densification of the paste structure, resulting in strength development of CFSC7 in the early hydration process. The leaching toxicity and radioactivity tests results indicate that the developed cementitious material composed of calcium silicate slag is environmentally acceptable. This study points out a promising direction for the proper utilization of calcium silicate slag in large quantities. PMID:26691955

  5. Valorization of lignite combustion residues and ferroalumina in the production of aggregates.

    PubMed

    Anagnostopoulos, I M; Stivanakis, V E; Angelopoulos, G N; Papamantellos, D C

    2010-02-15

    The present research study investigates the synergy of industrial solid by-products from lignite combustion (fly ash and bottom ash) and aluminum production (ferroalumina) in the production of lightweight aggregates (LWA). The process consists of two stages, pelletization and sintering. Bottom ash (BA) is used as the principal raw material in mixtures while ferroalumina (FAL) is added in lower percentages (5-30 wt%). BA carbon content is used as the fuel of sintering process in high temperatures, around 1250 degrees C, and gas generation is responsible for porous structure formation. Physical properties such as porosity, water absorption and bulk density, of sintering products are measured. Increase of FAL percentage in sintering mixtures results in decrease of porosity from 61% to 35% and of water absorption from 61% to 21% and in increase of bulk density from 1.02 g/cm(3) to 1.80 g/cm(3) of the produced aggregates. Aggregates produced by FAL addition up to 20 wt% are characterized as LWA. Aggregates formed are used in the production of concrete specimens. Compressive strength of concrete increases by increasing FAL addition in aggregates from 5 wt% to 15 wt% (highest strength value), while decrease by increasing FAL addition from 20 wt% to 30 wt%. FAL addition in lignite ashes sintering mixtures (up to 15 wt%) is considered as an important parameter for enhancing aggregates strength. PMID:19850411

  6. Geochemistry and mineralogy of Greek lignites from the Ioannina Basin

    SciTech Connect

    Gentzis, T.; Goodarzi, F.; Foscolos, A.E.

    1997-02-01

    Mineralogical and elemental composition of 26 lignites/lignitic shales and their ashes from the Ioannina Basin were examined using X-ray diffraction, X-ray fluorescence, and instrumental neutron activation analysis. Mineralogy consists of quartz, 2:1 interstratified layer silicates, kaolinite, and gypsum. Illite, calcite, amphiboles, feldspars, and pyrite are the minor minerals in the samples. The major oxides SiO{sub 2}, Al{sub 2}O{sub 3}, Fe{sub 2}O{sub 3}, TiO{sub 2}, and K{sub 2}O show an enrichment in the upper lignite-bearing interval within the succession, CaO shows the exact reverse trend, and Na{sub 2}O and MgO do not show any trends. Arsenic in the samples ranges from 2 to 46 ppm, Br from 10 to 25 ppm, Cl from 61 to 278 ppm, and Se from 2 to 14 ppm. Vertically, As content decreases from the shallower interval II to the deeper interval I. Within interval II, Cr and Br show a decrease from top to bottom. The concentration of Br and Cl is higher in the samples of low mineral matter, while the opposite is true for As. Laterally, there is an increase in Br and Cl from the northern to the central part of the basin, an increase of As in an eastern direction, and a decrease of Se in the same direction. Epigenetic processes related to high water table and subsurface water flow from the nearby phosphorite deposits are probably responsible for the high concentration of U, Mo, Sb, and possibly, V. The enrichment of Se is due to leaching from gypsum and/or anhydrite beds in the area. The rare earth elements follow variations in the low-temperature ash, but more specifically, the light REEs tend to mimic variations in Th and Al{sub 2}O{sub 3} concentration, and the heavy REEs follow the TiO{sub 2} variation.

  7. Modeling higher heating values of lignites

    SciTech Connect

    Demirbas, A.; Dincer, K.

    2008-07-01

    In this work, the elemental analysis results such as carbon (C), hydrogen (H), oxygen (O), nitrogen (N), and sulfur (S) were used for calculated higher heating values (HHVs) of 26 lignite samples from different areas of Turkey. The lignite samples have been tested with particle size of 0-0.05 mm. The HHVs of 26 lignite samples obtained from different Turkish sources were experimentally determined and can be calculated from the equation-based modeling. The HHVs (MJ/kg) of the lignite samples as a function of carbon (C), hydrogen (H), oxygen (O), nitrogen (N), and sulfur (S) was calculated from the following equation: HHV = 31.6(C) + 142.3(H) + 30.8(S) - 15.4(O) - 14.5(N) of which the correlation coefficients for the equation was 0.9891. HHVs calculated from the equation showed mean deviation of +0.1.

  8. Swelling of lignites in organic solvents

    SciTech Connect

    R.G. Makitra; D.V. Bryk

    2008-10-15

    Data on the swelling of Turkish lignites can be summarized using linear multiparameter equations that take into account various properties of solvents. Factors responsible for the amounts of absorbed solvents are the basicity and cohesion energy density of the solvents.

  9. Slag Penetration into Refractory Lining of Slagging Coal Gasifier

    SciTech Connect

    Matyas, Josef; Sundaram, S. K.; Rodriguez, Carmen P.; Edmondson, Autumn B.; Arrigoni, Benjamin M.

    2008-10-25

    The impurities in coal are converted into molten slag typically containing SiO2, FeO, CaO, and Al2O3 when coal feedstock is burned in slagging gasifiers. The slag flows down the gasifier sidewalls, dissolves, and penetrates and reacts with the refractory lining that protects the stainless steel shell of the gasifier from elevated temperatures (1300–1600°C). Refractories composed primarily of Cr2O3 have been found most resistant to slag corrosion, but they continue to fail performance requirements because of low resistance to spalling. Post-mortem analysis of high-chromia refractory bricks collected from commercial gasifiers suggests that the spalling is affected by the depth of slag penetration that is in turn affected by the wettability and interconnected porosity of the refractory as well as the slag viscosity. Laboratory tests were conducted to measure the viscosity of slags (Wyoming Powder River Basin [PRB], Pocahontas #3, and Pittsburgh #8), their contact angle on refractories (chromia-alumina [Aurex 75SR] and high-chromia [Serv 95 and Aurex 95P]), and the apparent porosity of selected refractories. In addition, the depth of slag penetration as a function of time and temperature was determined for various refractory-slag combinations. The results of laboratory tests were used to develop a refractory material that has high resistance to penetration by molten slag and thus has a potential to have a substantially longer service life than the materials currently being used.

  10. Utilization of Lightweight Materials Made from Coal Gasificaiton Slags

    SciTech Connect

    Choudhry, V.; Hadley, S.

    1996-12-31

    The integrated gasification combined-cycle (IGCC) coal conversion process has been demonstrated to be a clean, efficient, and environmentally acceptable method of generating power; however, it generates solid waste materials in relatively large quantities. For example, a 400-MW power plant using 4000 tons of 10% ash coal per day may generate over 440 tons/day of solid waste of slag, consisting of vitrified mineral matter and unburned carbon. The disposal of the wastes represents significant costs. Regulatory trends with respect to solid wastes disposal, landfill development costs and public concern make utilization of solid wastes a high-priority issue. As coal gasification technologies find increasing commercial applications for power generation or production of chemical feed stocks, it becomes imperative that slag utilization methods be developed, tested and commercialized in order to offset disposal costs. Praxis is working on a DOE/METC funded project to demonstrate the technical and economic feasibility of making lightweight and ultra-lightweight aggregates from slags left as solid by-products from the coal gasification process. The project objectives are to develop and demonstrate the technology for producing slag-based lightweight aggregates (SLA), to produce 10 tons of SLA products with different unit weights from two slags, to collect operational and emissions data from pilot-scale operations, and to conduct laboratory and commercial scale evaluations of SLA with conventional lightweight and ultra-lightweight aggregates.

  11. Mössbauer Studies of Thermal Power Plant Coal and Fly Ash

    NASA Astrophysics Data System (ADS)

    Taneja, S. P.

    Iron-57 Mössbauer spectroscopic studies were carried out at room temperature on samples of coal, slag (bottom ash) and mechanical ash collected from Bhatinda (India) thermal power plant. Hyperfine parameters such as isomer shift, quadrupole splitting and total internal magnetic field of 57Fe nuclei were used to characterize various iron-bearing minerals. The observed parameters indicate the presence of pyrite, siderite and ankerite in coal sample while magnetic fractions of mechanical ash and slag samples show the formation of hematite and Al-substituted magnesio-ferrite. The non-magnetic fraction of slag ash shows the dominance of Fe2+ phases while that of mechanical ash demonstrates the formation of both Fe2+ and Fe3+ phases. These findings are compared with Mössbauer and magnetic susceptibility studies on fly ash samples of Panipat (India) thermal power plant reported earlier.

  12. Co-firing of olive residue with lignite in bubbling FBC

    SciTech Connect

    Gogebakan, Z.; Gogebakan, Y.; Selcuk, N.

    2008-07-01

    The effect of biomass share on gaseous pollutant emissions from fluidized bed co-firing of various biomass fuels with high calorific value coals have extensively been investigated to date. However, effect of co-firing of olive residues with low calorific value lignites having high ash and sulfur contents has not been studied in bubbling fluidized bed combustors. In this study, experimental results of various runs pertaining to gaseous emissions (O{sub 2}, CO{sub 2}, CO, SO{sub 2}, NO, N{sub 2}O) from METU 0.3 MWt Atmospheric Bubbling Fluidized Bed Combustor (ABFBC) test rig co-firing olive residue with indigenous lignite at different biomass shares are presented. The results reveal that co-firing increases combustion efficiency irrespective of the biomass share and that increase in biomass share reduces N{sub 2}O and SO{sub 2} emissions considerably while increasing CO emission. O{sub 2}, CO{sub 2} and NO emissions are not found sensitive to increase in biomass share. Olive residues are co-fired with high ash and sulfur containing lignite without any operational problems.

  13. Speciation of copper in the thermally stabilized slag

    NASA Astrophysics Data System (ADS)

    Tuan, Y.-J.; Paul Wang, H.; Chang, J.-E.; Chao, C.-C.; Tsai, C.-K.

    2010-07-01

    The Taiwan universities laboratory hazardous wastes have been treated by incineration at the temperature range of 1173-1273 K. By X-ray absorption near edge structure (XANES) spectroscopy, mainly CuO and CuSO 4 are found in the incineration bottom and fly ashes. The incineration fly ash can be stabilized thermally at 1773 K in the plasma melting reaction chamber (integrated with the incinerator), and converted to slag. The concentration of leachable copper in the slag is reduced significantly mainly due to the fact that copper is encapsulated in the SiO 2 matrix. In addition, the refined extended X-ray adsorption fine structure (EXAFS) spectra of copper also indicate formation of the Cu-O-Si species in the slag as the bond distances of 1.95 Å for Cu-O and 2.67 Å for O-Si are observed. This work exemplifies utilization of the synchrotron X-ray absorption spectroscopy to facilitate the thermal stabilization treatments of the fly ash hazardous waste using the plasma melting method.

  14. Utilization of lightweight materials made from coal gasification slags

    SciTech Connect

    1998-09-30

    The integrated-gasification combined-cycle (IGCC) process is an emerging technology that utilizes coal for power generation and production of chemical feedstocks. However, the process generates large amounts of solid waste, consisting of vitrified ash (slag) and some unconverted carbon. In previous projects, Praxis investigated the utilization of ''as-generated'' slags for a wide variety of applications in road construction, cement and concrete production, agricultural applications, and as a landfill material. From these studies, we found that it would be extremely difficult for ''as-generated'' slag to find large-scale acceptance in the marketplace even at no cost because the materials it could replace were abundantly available at very low cost. It was further determined that the unconverted carbon, or char, in the slag is detrimental to its utilization as sand or fine aggregate. It became apparent that a more promising approach would be to develop a variety of value-added products from slag that meet specific industry requirements. This approach was made feasible by the discovery that slag undergoes expansion and forms a lightweight material when subjected to controlled heating in a kiln at temperatures between 1400 and 1700 F. These results confirmed the potential for using expanded slag as a substitute for conventional lightweight aggregates (LWA). The technology to produce lightweight and ultra-lightweight aggregates (ULWA) from slag was subsequently developed by Praxis with funding from the Electric Power Research Institute (EPRI), Illinois Clean Coal Institute (ICCI), and internal resources. The major objectives of the subject project are to demonstrate the technical and economic viability of commercial production of LWA and ULWA from slag and to test the suitability of these aggregates for various applications. The project goals are to be accomplished in two phases: Phase I, comprising the production of LWA and ULWA from slag at the large pilot scale, and

  15. Utilization of lightweight materials made from coal gasification slags

    SciTech Connect

    1999-12-30

    The integrated-gasification combined-cycle (IGCC) process is an emerging technology that utilizes coal for power generation and production of chemical feedstocks. However, the process generates large amounts of solid waste, consisting of vitrified ash (slag) and some unconverted carbon. In previous projects, Praxis investigated the utilization of as-generated slags for a wide variety of applications in road construction, cement and concrete production, agricultural applications, and as a landfill material. From these studies, the authors found that it would be extremely difficult for as-generated slag to find large-scale acceptance in the marketplace even at no cost because the materials it could replace were abundantly available at very low cost. It was further determined that the unconverted carbon, or char, in the slag is detrimental to its utilization as sand or fine aggregate. It became apparent that a more promising approach would be to develop a variety of value-added products from slag that meet specific industry requirements. This approach was made feasible by the discovery that slag undergoes expansion and forms a lightweight material when subjected to controlled heating in a kiln at temperatures between 1,400 and 1,700 F. These results confirmed the potential for using expanded slag as a substitute for conventional lightweight aggregates (LWA). The technology to produce lightweight and ultra-lightweight aggregates (ULWA) from slag was subsequently developed by Praxis with funding from the Electric Power Research Institute (EPRI), Illinois Clean Coal Institute (ICCI), and internal resources. The major objectives of the subject project are to demonstrate the technical and economic viability of commercial production of LWA and ULWA from slag and to test the suitability of these aggregates for various applications. The project goals are to be accomplished in two phases: Phase 1, comprising the production of LWA and ULWA from slag at the large pilot scale

  16. UTILIZATION OF LIGHTWEIGHT MATERIALS MADE FROM COAL GASIFICATION SLAGS

    SciTech Connect

    1998-12-24

    The integrated-gasification combined-cycle (IGCC) process is an emerging technology that utilizes coal for power generation and production of chemical feedstocks. However, the process generates large amounts of solid waste, consisting of vitrified ash (slag) and some unconverted carbon. In previous projects, Praxis investigated the utilization of ''as-generated'' slags for a wide variety of applications in road construction, cement and concrete production, agricultural applications, and as a landfill material. From these studies, we found that it would be extremely difficult for ''as-generated'' slag to find large-scale acceptance in the marketplace even at no cost because the materials it could replace were abundantly available at very low cost. It was further determined that the unconverted carbon, or char, in the slag is detrimental to its utilization as sand or fine aggregate. It became apparent that a more promising approach would be to develop a variety of value-added products from slag that meet specific industry requirements. This approach was made feasible by the discovery that slag undergoes expansion and forms a lightweight material when subjected to controlled heating in a kiln at temperatures between 1400 and 1700 F. These results confirmed the potential for using expanded slag as a substitute for conventional lightweight aggregates (LWA). The technology to produce lightweight and ultra-lightweight aggregates (ULWA) from slag was subsequently developed by Praxis with funding from the Electric Power Research Institute (EPRI), Illinois Clean Coal Institute (ICCI), and internal resources. The major objectives of the subject project are to demonstrate the technical and economic viability of commercial production of LWA and ULWA from slag and to test the suitability of these aggregates for various applications. The project goals are to be accomplished in two phases: Phase I, comprising the production of LWA and ULWA from slag at the large pilot scale, and

  17. Alteration of municipal and industrial slags under atmospheric conditions

    NASA Astrophysics Data System (ADS)

    Rafał Kowalski, Piotr; Michalik, Marek

    2014-05-01

    The Waste Management System in Poland is being consequently built since 1998. After important changes in legislation, local governments have taken over the duty of waste collection. New points of selective collection of wastes have been opened and new sorting and composting plants were built. The last stage of introducing the Waste Management System is construction of waste incineration power plants. From nine installations which were planned, six are now under construction and they will start operating within the next two years. It is assumed that the consumption of raw wastes for these installations will reach 974 thousand tons per year. These investments will result in increased slags and ashes production. Now in Poland several local waste incinerators are operating and predominant amount of produced incineration residues is landfilled. These materials are exposed to atmospheric conditions in time of short term storage (just after incineration) and afterwards for a longer period of time on the landfill site. During the storage of slags low temperature mineral transformations and chemical changes may occur and also some components can be washed out. These materials are stored wet because of the technological processes. The aim of this study is to investigate the influence of storage in atmospheric conditions on slags from incineration of industrial and municipal wastes. The experiment started in January 2013. During this period slag samples from incineration of industrial and municipal wastes were exposed to atmospheric conditions. Samples were collected after 6 and 12 months. Within this time the pH value was measured monthly, and during the experimental period remained constant on the level of 9.5. After 6 months of exposure only slight changes in mineral compositions were observed in slags. The results of XRD analysis of municipal slags showed increase in content of carbonate minerals in comparison to the raw slag samples. In industrial slags, a decrease in

  18. Apparatus having inductively coupled coaxial coils for measuring buildup of slay or ash in a furnace

    DOEpatents

    Mathur, Mahendra P.; Ekmann, James M.

    1989-01-01

    The buildup of slag or ash on the interior surface of a furnace wall is monitored by disposing two coils to form a transformer which is secured adjacent to the inside surface of the furnace wall. The inductive coupling between the two coils of the transformer is affected by the presence of oxides of iron in the slag or ash which is adjacent to the transformer, and the application of a voltage to one winding produces a voltage at the other winding that is related to the thickness of the slag or ash buildup on the inside surface of the furnace wall. The output of the other winding is an electrical signal which can be used to control an alarm or the like or provide an indication of the thickness of the slag or ash buildup at a remote location.

  19. SLAG CHARACTERIZATION AND REMOVAL USING PULSE DETONATION TECHNOLOGY DURING COAL GASIFICATION

    SciTech Connect

    DR. DANIEL MEI; DR. JIANREN ZHOU; DR. PAUL O. BINEY; DR. ZIAUL HUQUE

    1998-07-30

    Pulse detonation technology for the purpose of removing slag and fouling deposits in coal-fired utility power plant boilers offers great potential. Conventional slag removal methods including soot blowers and water lances have great difficulties in removing slags especially from the down stream areas of utility power plant boilers. The detonation wave technique, based on high impact velocity with sufficient energy and thermal shock on the slag deposited on gas contact surfaces offers a convenient, inexpensive, yet efficient and effective way to supplement existing slag removal methods. A slight increase in the boiler efficiency, due to more effective ash/deposit removal and corresponding reduction in plant maintenance downtime and increased heat transfer efficiency, will save millions of dollars in operational costs. Reductions in toxic emissions will also be accomplished due to reduction in coal usage. Detonation waves have been demonstrated experimentally to have exceptionally high shearing capability, important to the task of removing slag and fouling deposits. The experimental results describe the parametric study of the input parameters in removing the different types of slag and operating condition. The experimental results show that both the single and multi shot detonation waves have high potential in effectively removing slag deposit from boiler heat transfer surfaces. The results obtained are encouraging and satisfactory. A good indication has also been obtained from the agreement with the preliminary computational fluid dynamics analysis that the wave impacts are more effective in removing slag deposits from tube bundles rather than single tube. This report presents results obtained in effectively removing three different types of slag (economizer, reheater, and air-heater) t a distance of up to 20 cm from the exit of the detonation tube. The experimental results show that the softer slags can be removed more easily. Also closer the slag to the exit of

  20. Ash fusion study of West Virginia coals

    SciTech Connect

    Ashton, K.C., Smith, C.J.; Hohn, M.E.

    1984-12-01

    As more industries and utilities convert to coal, ash fusion information becomes more important for boiler design (waste disposal systems). For example, burning a low fusion temperature coal can cause slagging - the buildup of molten ash on boiler waterwall tubes. Not only is boiler efficiency lowered, but downtime is also increased. Recently, potential buyers of West Virginia coal have inquired frequently about ash fusion. However, the amount of information in the West Virginia Geological and Economic Survey's data base is limited to data from about 800 samples, 50% of which were collected in five counties. Thus, the survey is conducting a study of ash fusion temperatures for the state's coals, to increase available data and its geographic coverage. A Leco AF-500 automated ash fusion analyzer was used in this study, which addresses: 1) reliability of results from an automated analyzer, 2) comparison of automated data with conventional data, 3) techniques of sample preparation, high-temperature ashing, and cone preparation, 4) ash-fusion trends in the state, and 5) research developments. The research sought to develop for West Virginia coal a statistical correlation model relating ash-elemental data with fusion data, and to investigate the relationship between ash color and fusion temperature. (Light-colored ashes generally have higher fusion temperatures than darker ashes.)

  1. Nonequilibrium Sulfur Capture & Retention in an Air Cooled Slagging Coal Combustor

    SciTech Connect

    Bert Zauderer

    1998-04-21

    Calcium oxide injected in a slagging combustor reacts with the sulfur from coal combustion to form sulfur-bearing particles, which are deposited on the liquid slag layer on the combustor wall. Due to the low solubility of sulfur in slag, it must be rapidly drained from the combustor to limit sulfur gas re-evolution. Analysis indicated that slag mass flow rates in excess of 400 lb/hr should limit sulfur re-evolution. The objective of this 36 month project was to perform a series of tests to determine the factors that control the retention of the sulfur in the slag. 19 days of testing were completed prior to 9/30/97. In the present quarterly reporting period ending 12/31/97, 13 tests days were completed on co-firing coal and a high ash, rice husk biomass, which was selected to produce a high slag flow rate. Most of the test effort focussed on developing methods for feeding the very low density rice husks into combustor. Various levels of mineral matter from coal ash, rice husk ash, calcium sulfate, and calcium oxide was injected in the combustor during these 13 tests. The peak mineral matter, injection rate was 592 lb/hr for a period of about one-hour. No significant sulfur concentration was measured in the slag removed from the combustor. This may be due to the brief test duration, and longer duration tests are planned for the next quarter. The two major accomplishments in this quarter are the successful co-firing of coal and biomass in the slagging combustor. This is a major technical milestone due to its application to greenhouse gas emission reduction. It was not in the original project plan. Also, the total of 31 test days completed by 12/31/97 is double the number originally planned.

  2. Utilization of lightweight materials made from coal gasification slags. Quarterly report, September--November 1995

    SciTech Connect

    1995-12-01

    Integrated-gasification combined-cycle (IGCC) technology is an emerging technology that utilizes coal for power generation and production of chemical feedstocks. However, the process generates large amounts of solid waste, consisting of vitrified ash (slag) and some unconverted carbon. Slag undergoes expansion and forms a lightweight material when subjected to controlled heating in a kiln. The potential exists for using expanded slag as a substitute for conventional lightweight aggregates (LWA). The technology to produce lightweight and ultra-lightweight aggregates (ULWA) from slag was subsequently developed. The project scope consists of collecting a 20-ton sample of slag (primary slag), processing it for char removal, and subjecting it to pyroprocessing to produce expanded slag aggregates of various size gradations and unit weights, ranging from 12 to 50 lb/ft{sup 3}. A second smaller slag sample will be used for confirmatory testing. The expanded slag aggregates will then be tested for their suitability in manufacturing precast concrete products (e.g., masonry blocks and roof tiles) and insulating concrete, first at the laboratory scale and subsequently in commercial manufacturing plants. These products will be evaluated using ASTM and industry test methods. Technical data generated during production and testing of the products will be used to assess the overall technical viability of expanded slag production. In addition, a market assessment will be made based on an evaluation of both the expanded slag aggregates and the final products, and market prices for these products will be established in order to assess the economic viability of these utilization technologies.

  3. Moessbauer analysis of Lewisville, Texas, archaeological site lignite and hearth samples. Environmental geology notes

    SciTech Connect

    Shiley, R.H.; Hughes, R.E.; Cahill, R.A.; Konopka, K.L.; Hinckley, C.C.

    1985-01-01

    The Lewisville site, located in Denton County on the Trinity River north of Dallas, Texas, was thought to provide evidence of the earliest human activity in the western hemisphere. Radiocarbon dates of 37,000 to 38,000 B.P. determined for the site in the late 1950s conflicted with the presence of a Clovis point, which would fix the age of the site between 11,000 and 11,500 B.P. It was hypothesized (Johnson, 1982) that Clovis people were burning lignite from nearby outcrops: lignite in hearth residues would give older than actual ages by radiocarbon dating. X-ray diffraction and instrumental neutron-activation analysis proved inconclusive; however, Moessbauer spectroscopy indicated that hematite, a pyrite combustion product, was present in the ash. From this evidence the authors conclude that there is some support for the hypothesis.

  4. Effect of ash circulation in gasification melting system on concentration and leachability of lead in melting furnace fly ash.

    PubMed

    Okada, Takashi; Suzuki, Masaru

    2013-11-30

    In some gasification-melting plants, generated melting furnace fly ash is returned back to the melting furnace for converting the ash to slag. This study investigated the effect of such ash circulation in the gasification-melting system on the concentration and leachability of lead in the melting furnace fly ash. The ash circulation in the melting process was simulated by a thermodynamic calculation, and an elemental analysis and leaching tests were performed on a melting furnace fly ash sample collected from the gasification-melting plant with the ash circulation. It was found that by the ash circulation in the gasification-melting, lead was highly concentrated in the melting furnace fly ash to the level equal to the fly ash from the ash-melting process. The thermodynamic calculation predicted that the lead volatilization by the chlorination is promoted by the ash circulation resulting in the high lead concentration. In addition, the lead extraction from the melting furnace fly ash into a NaOH solution was also enhanced by the ash circulation, and over 90% of lead in the fly ash was extracted in 5 min when using 0.5 mol l(-1) NaOH solution with L/S ratio of 10 at 100 °C. Based on the results, a combination of the gasification-melting with the ash circulation and the NaOH leaching method is proposed for the high efficient lead recovery. PMID:24121545

  5. Nonequilibrium sulfur capture and retention in an air cooled slagging coal combustor

    SciTech Connect

    Zauderer, B.

    1997-08-13

    Calcium oxide injected in a slagging combustor react with the sulfur from coal combustion to form sulfur bearing particles, which are deposited on the liquid slag layer on the combustor wall. Due to the low solubility of sulfur in slag, it must be drained from the combustor to limit sulfur gas re-evolution. Analysis indicated that slag mass flow rates in excess of 400 lb/hr should limit sulfur re- evolution. The objective of this 36 month project was to perform a series of 16 one day tests to determine the factors that control the retention of the sulfur in the slag. In the present quarterly reporting period, 3 days of combustor tests were performed, bringing the total number of tests performed to 19. Two of the test were a repeat of two tests performed in the previous quarter with a high, 37% ash, Indian coal. The high slag flow rate with that coal resulted in the highest observed sulfur retention to-date, namely 20% of the injected sulfur. In the present quarter, this test was repeated with the same coal feed rate but with 75% longer period of 2.4 hours. The total mineral matter injected was 635 lb/hr, compared to only 19.7 lb/hr of sulfur, of which 75% was from injected gypsum. However, despite excellent slag flow from the previous Indian coal tests, only 5.8% of the sulfur from the gypsum reported to the slag. Since substantial amounts slag remained on the combustor walls, it is concluded that still longer duration tests are required to establish equilibrium conditions. Current efforts are focused on finding a U.S. source of high ash coal to implement additional tests.

  6. Nonequilibrium Sulfur Capture and Retention in an Air Cooled Slagging Coal Combustor.

    SciTech Connect

    Zauderer, B.

    1997-09-30

    Calcium oxide injected in a slagging combustor react with the sulfur from coal combustion to form sulfur bearing particles, which are deposited on the liquid slag layer on the combustor wall. Due to the low solubility of sulfur in slag, it must be drained from the combustor to limit sulfur gas re-evolution. Analysis indicated that slag mass flow rates in excess of 400 lb/hr should limit sulfur re-evolution. The objective of this 36 month project was to perform a series of 16 one day tests to determine the factors that control the retention of the sulfur in the slag. In the present quarterly reporting period, 3 days of combustor tests were performed, bringing the total number of tests performed to 19. Two of the test were a repeat of two tests performed in the previous quarter with a high, 37% ash, Indian coal. The high slag flow rate with that coal resulted in the highest observed sulfur retention to-date, namely 20% of the injected sulfur. In the present quarter, this test was repeated with the same coal feed rate but with 75% longer period of 2.4 hours. The total mineral matter injected was 635 lb/hr, compared to only 19.7 lb/hr of sulfur, of which 75% was from injected gypsum. However, despite excellent slag flow from the previous Indian coal tests, only 5.8% of the sulfur from the gypsum reported to the slag. Since substantial amounts slag remained on the combustor walls, it is concluded that still longer duration tests are required to establish equilibrium conditions. Current efforts are focused on finding a U.S. source of high ash coal to implement additional tests.

  7. Slag recycling of irradiated vanadium

    SciTech Connect

    Gorman, P.K.

    1995-04-05

    An experimental inductoslag apparatus to recycle irradiated vanadium was fabricated and tested. An experimental electroslag apparatus was also used to test possible slags. The testing was carried out with slag materials that were fabricated along with impurity bearing vanadium samples. Results obtained include computer simulated thermochemical calculations and experimentally determined removal efficiencies of the transmutation impurities. Analyses of the samples before and after testing were carried out to determine if the slag did indeed remove the transmutation impurities from the irradiated vanadium.

  8. Gasifier slag and feedstock characterization. Final technical report

    SciTech Connect

    Lancet, M.S.; Havekotte, D.E.; Sim, F.A.; Sivasubramanian, R.

    1983-03-01

    The purpose of this subcontract work was to establish the gasification reactivities and ash and slag properties of several Midwestern coals and Kerr-McGee ash concentrates which would be available to the SRC-I demo plant as gasifier feedstocks to produce process hydrogen. The ash concentrates are high ash by-products of the Kerr-McGee critical solvent deashing (CSD) process which is a leading candidate for solids removal at the SRC-I demo plant. Four Midwestern coals, three from Kentucky and one from Illinois, and six Kerr-McGee ash concentrate samples produced at the SRC-I pilot plant in Wilsonville, Alabama, were characterized in this work. In addition to complete chemical analysis, a petrographic analysis was performed on each coal sample. CO/sub 2/-carbon reactivities of chars produced during the pressurized coking at simulated gasifier conditions of all ten materials were determined. These reactivities were measured under pressure (300 psig) at 800/sup 0/C, and at 950/sup 0/C and 1 atmosphere. The results of the atmospheric high temperature reactivity determinations suggest that all materials tested should be sufficiently reactive for use in a Koppers-Totzek or Texaco slagging gasifier. The pressurized, 800/sup 0/C reactivities are fairly low for every material tested. This is consistent with the reactivities of Eastern and midcontinent bituminous coals and limits the desirability of using these coals and Kerr-McGee ash concentrates as feedstocks to lower temperature, when coupled with the low fusion temperatures of the ashes from all of these materials, virtually precludes their economic useage in a conventional (dry-bottom) Lurgi gasifier. 11 references, 5 figures, 26 tables.

  9. Slag-Refractory Interaction in Slagging Coal Gasifiers

    SciTech Connect

    Matyas, Josef; Sundaram, S. K.; Hicks, Brent J.; Edmondson, Autumn B.; Arrigoni, Benjamin M.

    2008-03-03

    The combustion chamber of slagging coal gasifiers is lined with refractories to protect the stainless steel shell of the gasifier from elevated temperatures and corrosive attack of the coal slag. Refractories composed primarily of Cr2O3 have been found most resistant to slag corrosion, but they continue to fail performance requirements. Post-mortem analysis of high-chromia refractory bricks collected from commercial gasifiers suggests that slag penetration and subsequent spalling of refractory are the cause of significantly shorter service life of gasifier refractories. Laboratory tests were conducted to determine the penetration depth of three slags representative of a wide variety of coals in the United States into chromia-alumina and two high-chromia refractories. Variables tested were refractory-slag combinations and two partial pressures of O2. Slag penetration depths were measured from spliced images of each refractory. Samples heated to 1470°C for 2 hrs had maximum penetration depths ranging from 1.99±0.15 mm to at least 21.6 mm. Aurex 95P, a high-chromia refractory containing 3.3% phosphorous pentoxide (P2O5), showed the least slag penetration of all refractories tested. P2O5 likely reacts with the slags to increase their viscosity and restrict molten slag penetration. Experimental data on the slag-refractory interaction will be incorporated into mathematical model that will be used to 1) identify critical conditions at which refractory corrosion sharply increases, and 2) predict the service life of a gasifier refractory.

  10. Chemical and physical properties of plasma slags containing various amorphous volume fractions.

    PubMed

    Kuo, Yi-Ming; Wang, Chih-Ta; Tsai, Cheng-Hsien; Wang, Lin-Chi

    2009-02-15

    In this study, municipal solid waste incinerator fly ash was vitrified using a plasma torch. The fly ash contained rich Ca, causing a high basicity of 2.43. Pure quartz was used as an additive to adjust the basicity. BET surface area analysis, X-ray diffraction analysis, and a scanning electron microscope were used to examine the physical properties of slags. The chemical stability and the acid resistance of slags were evaluated using the toxicity characteristics leaching procedure and tests of acid bathing. The results indicate that the plasma torch effectively vitrified the fly ash. Anthropogenic metals with low boiling points, such as Cd, Pb, and Zn, were predominately vaporized into flue gas. Most of the metals with high boiling points, such as Cr, Cu, and Mn, remained in the slag. After the vitrification, hazardous metals were noticeably immobilized in all slags. However, the slags with higher amorphous volume fractions were more effective in metal immobilization and in resisting acid corrosion. This indicates that SiO(2) enhanced the formation of the glassy amorphous phase and improved the resistance of acid corrosion and the immobilization of hazardous metals. PMID:18573600

  11. NONEQUILIBRIUM SULFUR CAPTURE AND RETENTION IN AN AIR COOLED SLAGGING COAL COMBUSTOR

    SciTech Connect

    Dr. Bert Zauderer

    1999-03-15

    Calcium oxide injected in a slagging combustor reacts with the sulfur from coal combustion to form sulfur-bearing particles. They are deposited on the liquid slag layer on the combustor wall. Due to the low solubility of sulfur in slag, slag must be rapidly drained from the combustor to limit sulfur gas re-evolution. Analysis indicated that slag mass flow rates in excess of 400 lb/hr should limit sulfur re-evolution. The objective of this 42-month project was to perform a series of tests to determine the factors that control the retention of the sulfur in the slag. 36 days of testing on the combustor were completed prior to the end of this reporting period, 12/31/98. This compares with 16 tests required in the original project plan. Combustor tests in early 1997 with high (37%) ash, Indian coal confirmed that high slag mass flow rates of about 500 lb/hr resulted in retention in the slag of up to 20% of the injected sulfur content mineral matter. To further increase the slag flow rate, rice husks, which contain 20% ash, and rice husk char, which contain 70% ash, were co-fired with coal in the combustor. A series of 13 combustor tests were performed in fourth quarter of 1997 and a further 6 tests were performed in January 1998 and in the summer of 1998. The test objective was to achieve slag flow rates between 500 and 1,000 lb/hr. Due to the very low bulk density of rice husk, compared to pulverized coal, almost the entire test effort focused on developing methods for feeding the rice husks into combustor. In the last test of December 1997, a peak mineral matter, injection rate of 592 lb/hr was briefly achieved by injection of coal, rice husk char, gypsum, and limestone into the combustor. However, no significant sulfur concentration was measured in the slag removed from the combustor. The peak injection rate reached with biomass in the 1997 tests was 310 lb/hr with rice husk, and 584 lb/hr with rice husk char.

  12. Utilization of lightweight materials made from coal gasification slags. Quarterly report, June 1--August 31, 1996

    SciTech Connect

    1996-12-31

    Integrated-gasification combined-cycle (IGCC) technology is an emerging technology that utilizes coal for power generation and production of chemical feedstocks. However, the process generates large amounts of solid waste, consisting of vitrified ash (slag) and some unconverted carbon. In previous projects, Praxis investigated the utilization of ``as-generated`` slags for a wide variety of applications in road construction, cement and concrete production, agricultural applications, and as a landfill material. From these studies, we found that it would be extremely difficult for ``as-generated`` slag to find large-scale acceptance in the marketplace even at no cost because the materials it could replace were abundantly available at very low cost. It was further determined that the unconverted carbon, or char, in the slag is detrimental to its utilization as sand or fine aggregate. It became apparent that a more promising approach would be to develop a variety of value-added products from slag that meet specific industry requirements. This approach was made feasible by the discovery that slag undergoes expansion and forms a lightweight material when subjected to controlled heating in a kiln at temperatures between 1400 and 17000F. These results confirmed the potential for using expanded slag as a substitute for conventional lightweight aggregates (LWA). The technology to produce lightweight and ultra-lightweight aggregates (ULWA) from slag was subsequently developed by Praxis. The major objectives of the subject project are to demonstrate the technical and economic viability of commercial production of LWA and ULWA from slag and to test the suitability of these aggregates for various applications. The project goals are to be accomplished in two phases: Phase 1, comprising the production of LWA and ULWA from slag at the large pilot-scale, and Phase 2, which involves commercial evaluation of these aggregates in a number of applications. Accomplishments are described.

  13. Usage of fly ash as a coal desulphurization reagent

    SciTech Connect

    Yaman, S.; Kuecuekbayrak, S.

    1996-12-31

    This paper covers the direct usage of fly ash to remove sulphur from coal. Experiments were carried out on a high sulphur Turkish lignite. 5 g of fly ash was extracted in 200 ml of water under pressure and the dilute solution containing water extractable parts of fly ash was used as desulphurization reagent. Oxygen pressure was created over desulphurization medium during the extraction period by which dissolved oxygen was concentrated in the solution. Effects of temperature, partial pressure of oxygen, and time were investigated in the ranges of 403--498 K, 0.0--1.5 MPa and 15--90 min, respectively.

  14. Vitrification of fly ash by swirling-flow furnace

    SciTech Connect

    Ito, Tadashi

    1996-12-31

    According to the amendment of the Waste Disposal and Public Cleansing Law of 1992, fly ash is regulated as Specially controlled waste and wide attention is now being paid to the melting and vitrification treatment of fly ash, which can reduce overall volume, detoxify and recover sources. Kobe Steel has demonstrated its operation using a swirling-flow furnace and has perfected a vitrification technique. The demonstration test has confirmed stable melting, high decomposition ratio of dioxins and the soundness of the slag. Kobe Steel has successfully developed a new technique for heightening the quality of slag and a new process for the heavy metals recovery from collected dust.

  15. Utilization of lightweight materials made from coal gasification slags. Quarterly report, March 1--May 31, 1996

    SciTech Connect

    1996-12-31

    Integrated-gasification combined-cycle (IGCC) technology is an emerging technology that utilizes coal for power generation and production of chemical feedstocks. However, the process generates large amounts of solid waste, consisting of vitrified ash (slag) and some unconverted carbon. The major objectives of the subject project are to demonstrate the technical and economic viability of commercial production of lightweight aggregates (LWA) and ultra-lightweight (ULWA) from slag and to test the suitability of these aggregates for various applications. The project goals are to be accomplished in two phases: Phase 1, comprising the production of LWA and ULWA from slag at the large pilot-scale, and Phase 2, which involves commercial evaluation of these aggregates in a number of applications. The following significant events occurred during this reporting period: testing of slag-based lightweight aggregates for roof tile and concrete applications.

  16. Utilization of lightweight materials made from coal gasification slags. Quarterly report, December 1994--February 1995

    SciTech Connect

    1995-03-01

    Integrated-gasification combined-cycle (IGCC) technology is an emerging technology that utilizes coal for power generation and production of chemical feedstocks. However, this process generates large amounts of solid waste, consisting of vitrified ash (slag) along with some unconverted carbon, which is disposed of as solid waste. The objectives of this project is to demonstrate the technical and economic viability of slag utilization technologies for commercial production of lightweight aggregates (LWA) and ultra-lightweight aggregates (ULWA) from slag and to test the suitability of these aggregates for various applications. The scheduled date for completing Phase I, which includes production of LWA and ULWA from slag at the large pilot-scale, is 14 December 1995. The scheduled start date for Phase II, which involves commercial utilization of these aggregates in a number of applications, is 15 December 1995, and the scheduled completion date of the project is 14 March 1997.

  17. Study of Decision Index for Ignition Timing of Slag Melting Burner

    NASA Astrophysics Data System (ADS)

    Murata, Hiroshi; Nakajima, Chikahito; Watanabe, Hiroaki

    In coal gasification plants, coal ash is discharged as molten slag. If the molten slag solidifies and is not discharged, an operator who monitors the plant throughout the day ignites a melting burner and removes the solidified slag. However, the use of this burner decreases the efficiency of the gasifier. Therefore, objective and appropriate automatic decision of ignition timing for the slag melting burner is necessary for economical operation, thereby reducing the operator's work load. In this report, we propose a decision index for ignition timing of the melting burner using monitoring videos. We have evaluated our method using 54 actual monitoring videos, and we have shown the applicability of automatically deciding the ignition timing.

  18. ACTIVATED CARBON FROM LIGNITE FOR WATER TREATMENT

    SciTech Connect

    Edwin S. Olson; Daniel J. Stepan

    2000-07-01

    High concentrations of humate in surface water result in the formation of excess amounts of chlorinated byproducts during disinfection treatment. These precursors can be removed in water treatment prior to disinfection using powdered activated carbon. In the interest of developing a more cost-effective method for removal of humates in surface water, a comparison of the activities of carbons prepared from North Dakota lignites with those of commercial carbons was conducted. Previous studies indicated that a commercial carbon prepared from Texas lignite (Darco HDB) was superior to those prepared from bituminous coals for water treatment. That the high alkali content of North Dakota lignites would result in favorable adsorptive properties for the very large humate molecules was hypothesized, owing to the formation of larger pores during activation. Since no standard humate test has been previously developed, initial adsorption testing was performed using smaller dye molecules with various types of ionic character. With the cationic dye, methylene blue, a carbon prepared from a high-sodium lignite (HSKRC) adsorbed more dye than the Darco HDB. The carbon from the low-sodium lignite was much inferior. With another cationic dye, malachite green, the Darco HDB was slightly better. With anionic dyes, methyl red and azocarmine-B, the results for the HSKRC and Darco HDB were comparable. A humate test was developed using Aldrich humic acid. The HSKRC and the Darco HDB gave equally high adsorption capacities for the humate (138 mg/g), consistent with the similarities observed in earlier tests. A carbon prepared from a high-sodium lignite from a different mine showed an outstanding improvement (201 mg/g). The carbons prepared from the low-sodium lignites from both mines showed poor adsorption capacities for humate. Adsorption isotherms were performed for the set of activated carbons in the humate system. These exhibited a complex behavior interpreted as resulting from two types

  19. Thermal behaviour of ESP ash from municipal solid waste incinerators.

    PubMed

    Yang, Y; Xiao, Y; Wilson, N; Voncken, J H L

    2009-07-15

    Stricter environmental regulations demand safer treatment and disposal of incinerator fly ashes. So far no sound technology or a process is available for a sustainable and ecological treatment of the waste incineration ashes, and only partial treatment is practised for temporary and short-term solutions. New processes and technology need to be developed for comprehensive utilization and detoxification of the municipal solid waste (MSW) incinerator residues. To explore the efficiency of thermal stabilisation and controlled vitrification, the thermal behaviour of electrostatic precipitator (ESP) ash was investigated under controlled conditions. The reaction stages are identified with the initial moisture removal, volatilization, melting and slag formation. At the temperature higher than 1100 degrees C, the ESP ashes have a quicker weight loss, and the total weight loss reaches up to 52%, higher than the boiler ash. At 1400 degrees C a salt layer and a homogeneous glassy slag were formed. The effect of thermal treatment on the leaching characteristics of various elements in the ESP ash was evaluated with the availability-leaching test. The leaching values of the vitrified slag are significantly lowered than that of the original ash. PMID:19150174

  20. Influence of slag chemistry on the hydration of alkali-activated blast-furnace slag - Part I: Effect of MgO

    SciTech Connect

    Ben Haha, M.; Lothenbach, B. Le Saout, G.; Winnefeld, F.

    2011-09-15

    The hydration and the microstructure of three alkali activated slags (AAS) with MgO contents between 8 and 13 wt.% are investigated. The slags were hydrated in the presence of two different alkaline activators, NaOH and Na{sub 2}SiO{sub 3}.5H{sub 2}O (WG). Higher MgO content of the slag resulted in a faster reaction and higher compressive strengths during the first days. The formation of C(- A)-S-H and of a hydrotalcite-like phase was observed in all samples by X-ray diffraction (XRD), thermal analysis (TGA) and scanning electron microscopy (SEM) techniques. Increasing the MgO content of the slag from 8 to 13% increased the amount of hydrotalcite and lowered the Al uptake by C-S-H resulting in 9% higher volume of the hydrates and a 50 to 80% increase of the compressive strength after 28 days and longer for WG activated slag pastes. For NaOH activated slags only a slight increase of the compressive strength was measured.

  1. Chemical composition in relation with biomass ash structure

    NASA Astrophysics Data System (ADS)

    Holubcik, Michal; Jandacka, Jozef

    2014-08-01

    Biomass combustion can be more complicated like combustion of fossil fuels because it is necessary to solve problems with lower ash melting temperature. It can cause a lot of problems during combustion process. Chemical composition of biomass ash has great impact on sinters and slags creation in ash because it affects structure of heated ash. In this paper was solved relation between chemical composition and structure of heated ash from three types of biomass (spruce wood, miscanthus giganteus and wheat straw). Amount of SiO2, CaO, MgO, Al2O3 and K2O was determined. Structure of heated ash was optically determined after heating to 1000 °C or 1200 °C. Results demonstrated that chemical composition has strong effect on structure and color of heated ash.

  2. Advanced power assessment for Czech lignite. Task 3.6, Volume 1

    SciTech Connect

    Sondreal, E.A.; Mann, M.D.; Weber, G.W.; Young, B.C.

    1995-12-01

    The US has invested heavily in research, development, and demonstration of efficient and environmentally acceptable technologies for the use of coal. The US has the opportunity to use its leadership position to market a range of advanced coal-based technologies internationally. For example, coal mining output in the Czech Republic has been decreasing. This decrease in demand can be attributed mainly to the changing structure of the Czech economy and to environmental constraints. The continued production of energy from indigenous brown coals is a major concern for the Czech Republic. The strong desire to continue to use this resource is a challenge. The Energy and Environmental Research Center undertook two major efforts recently. One effort involved an assessment of opportunities for commercialization of US coal technologies in the Czech Republic. This report is the result of that effort. The technology assessment focused on the utilization of Czech brown coals. These coals are high in ash and sulfur, and the information presented in this report focuses on the utilization of these brown coals in an economically and environmentally friendly manner. Sections 3--5 present options for utilizing the as-mined coal, while Sections 6 and 7 present options for upgrading and generating alternative uses for the lignite. Contents include Czech Republic national energy perspectives; powering; emissions control; advanced power generation systems; assessment of lignite-upgrading technologies; and alternative markets for lignite.

  3. Synthetic Coal Slag Infiltration into Varying Refractory Materials

    SciTech Connect

    Kaneko, Tetsuya K; Thomas, Hugh; Bennett, James P; Sridhar, Seetharaman

    2012-10-01

    The infiltrations of synthetic coal slag into 99%Al{sub 2}O{sub 3}, 85%Al{sub 2}O{sub 3}–15%SiO{sub 2}, and 90%Cr{sub 2}O{sub 3}–10%Al{sub 2}O{sub 3} refractories with a temperature gradient induced along the penetration direction were compared to one another. The infiltrating slag was synthesized with a composition that is representative of an average of the ash contents from U S coal feedstock. Experiments were conducted with a hot-face temperature of 1450°C in a CO/CO{sub 2} atmosphere. Minimal penetration was observed in the 90%Cr{sub 2}O{sub 3}–10%Al{sub 2}O{sub 3} material because interactions between the refractory and the slag produced a protective layer of FeCr{sub 2}O{sub 4}, which impeded slag flow into the bulk of the refractory. After 5 h, the 99%Al{sub 2}O{sub 3} sample exhibited an average penetration of 12.7 mm whereas the 85%Al{sub 2}O{sub 3}–15%SiO{sub 2} sample showed 3.8 mm. Slag infiltrated into the 99%Al{sub 2}O{sub 3} and 85%Al{sub 2}O{sub 3}–15%SiO{sub 2} refractory systems by dissolving the respective refractories' matrix materials, which consist of fine Al{sub 2}O{sub 3} particles and an amorphous alumino-silicate phase. Due to enrichment in SiO{sub 2}, a network-former, infiltration into the 85%Al{sub 2}O{sub 3}–15%SiO{sub 2} system yielded a higher viscosity slag and hence, a shallower penetration depth. The results suggest that slag infiltration can be limited by interactions with the refractory through the formation of either a solid layer that physically impedes fluid flow or a more viscous slag that retards infiltration.

  4. Inorganic constituents of some Turkish lignites

    SciTech Connect

    Yaman, S.; Taptik, Y.; Yavuz, R.; Kuecuekbayrak, S.

    1996-12-31

    In this study the mineral matter contents of two different Turkish lignite samples from Cayirhan and Tuncbilek regions were isolated by means of mild oxidation of organic matrix applying H{sub 2}O{sub 2}/HCOOH treatment. The isolated minerals were analyzed by XRD and FTIR techniques and constituents of the minerals were investigated qualitatively.

  5. Optical properties of fly ash. Volume 2, Final report

    SciTech Connect

    Self, S.A.

    1994-12-01

    Research performed under this contract was divided into four tasks under the following headings: Task 1, Characterization of fly ash; Task 2, Measurements of the optical constants of slags; Task 3, Calculations of the radiant properties of fly ash dispersions; and Task 4, Measurements of the radiant properties of fly ash dispersions. Tasks 1 and 4 constituted the Ph.D. research topic of Sarbajit Ghosal, while Tasks 2 and 3 constituted the Ph.D. research topic of Jon Ebert. Together their doctoral dissertations give a complete account of the work performed. This final report, issued in two volumes consists of an executive summary of the whole program followed by the dissertation of Ghosal and Ebert. Volume 2 contains the dissertation of Ebert which covers the measurements of the optical constants of slags, and calculations of the radiant properties of fly ash dispersions. A list of publications and conference presentations resulting from the work is also included.

  6. Ash Analysis

    NASA Astrophysics Data System (ADS)

    Marshall, Maurice R.

    Ash refers to the inorganic residue remaining after either ignition or complete oxidation of organic matter in a foodstuff. A basic knowledge of the characteristics of various ashing procedures and types of equipment is essential to ensure reliable results. Two major types of ashing are used: dry ashing, primarily for proximate composition and for some types of specific mineral analyses; wet ashing (oxidation), as a preparation for the analysis of certain minerals. Microwave systems now are available for both dry and wet ashing, to speed the processes. Most dry samples (i.e., whole grain, cereals, dried vegetables) need no preparation, while fresh vegetables need to be dried prior to ashing. High-fat products such as meats may need to be dried and fat extracted before ashing. The ash content of foods can be expressed on either a wet weight (as is) or on a dry weight basis. For general and food-specific information on measuring ash content, see references (1-11).

  7. Low-Chrome/Chrome Free Refractories for Slagging Gasifiers

    SciTech Connect

    Bennett, J.P.; Kwong, K.-S.; Powell, C.P.; Thomas, H.; Petty, A.V., Jr.

    2007-01-01

    Gasifiers are containment vessels used to react carbon-containing materials with oxygen and water, producing syngas (CO and H2) that is used in chemical and power production. It is also a potential source of H2 in a future hydrogen economy. Air cooled slagging gasifiers are one type of gasifier, operating at temperatures from 1275-1575º C and at pressures of 400 psi or higher. They typically use coal or petroleum coke as the carbon source, materials which contain ash impurities that liquefy at the gasification temperatures, producing liquid slag in quantities of 100 or more tons/day, depending on the carbon fed rate and the percent ash present in the feedstock. The molten slag is corrosive to refractory linings, causing chemical dissolution and spalling. The refractory lining is composed of chrome oxide, alumina, and zirconia; and is replaced every 3-24 months. Gasifier users would like greater on-line availability and reliability of gasifier liners, something that has impacted gasifier acceptance by industry. Research is underway at NETL to improve refractory service life and to develop a no-chrome or low-chrome oxide alternative refractory liner. Over 250 samples of no- or low-chrome oxide compositions have been evaluated for slag interactions by cup testing; with potential candidates for further studies including those with ZrO2, Al2O3, and MgO materials. The development of improved liner materials is necessary if technologies such as IGCC and DOE’s Near Zero Emissions Advanced Fossil Fuel Power Plant are to be successful and move forward in the marketplace.

  8. Utilization of lightweight materials made from coal gasification slags. Quarterly report, June--August 1995

    SciTech Connect

    1995-09-01

    Integrated-gasification combined-cycle (IGCC) technology is an emerging technology that utilizes coal for power generation and production of chemical feedstocks. However, the process generates large amounts of solid waste, consisting of vitrified ash (slag) and some unconverted carbon. In previous projects, Praxis investigated the utilization of {open_quotes}as-generated{close_quotes} slags for a wide variety of applications in road construction, cement and concrete production, agricultural applications, and as a landfill material. From these studies, we found that it would be extremely difficult for {open_quotes}as-generated{close_quotes} slag to find large-scale acceptance in the marketplace even at no cost because the materials it could replace were abundantly available at very low cost. It was further determined that the unconverted carbon, or char, in the slag is detrimental to its utilization as sand or fine aggregate. It became apparent that a more promising approach would be to develop a variety of value-added products from slag that meet specific industry requirements. This approach was made feasible by the discovery that slag undergoes expansion and forms a lightweight material when subjected to controlled heating in a kiln at temperatures between 1400 and 1700{degrees}F. These results indicated the potential for using expanded slag as a substitute for conventional lightweight aggregates (LWA). The technology to produce lightweight and ultra-lightweight aggregates (ULWA) from slag was subsequently developed by Praxis with funding from the Electric Power Research Institute (EPRI), Illinois Clean Coal Institute (ICCI), and internal resources. The major objectives of the subject project are to demonstrate the technical and economic viability of commercial production of LWA and ULWA from slag and to test the suitability of these aggregates for various applications.

  9. Destruction of inorganic municipal solid waste incinerator fly ash in a DC arc plasma furnace.

    PubMed

    Zhao, Peng; Ni, Guohua; Jiang, Yiman; Chen, Longwei; Chen, Mingzhou; Meng, Yuedong

    2010-09-15

    Due to the toxicity of dioxins, furans and heavy metals, there is a growing environmental concern on municipal solid waste incinerator (MSWI) fly ash in China. The purpose of this study is directed towards the volume-reduction of fly ash without any additive by thermal plasma and recycling of vitrified slag. This process uses extremely high-temperature in an oxygen-starved environment to completely decompose complex waste into very simple molecules. For developing the proper plasma processes to treat MSWI fly ash, a new crucible-type plasma furnace was built. The melting process metamorphosed fly ash to granulated slag that was less than 1/3 of the volume of the fly ash, and about 64% of the weight of the fly ash. The safety of the vitrified slag was tested. The properties of the slag were affected by the differences in the cooling methods. Water-cooled and composite-cooled slag showed more excellent resistance against the leaching of heavy metals and can be utilized as building material without toxicity problems. PMID:20542633

  10. A study of uranium and molybdenum in a South Texas lignite

    SciTech Connect

    Ilger, J.D.

    1989-01-01

    The modes of occurrence of U and Mo in a South Texas lignite (Eocene, Jackson Group, Whitsett Formation) have been investigated in detail. The distribution of U and Mo in the whole coal density separates indicates variable modes of occurrence predominantly in finely disseminated form. The relative enrichment of U in the heaviest density separate indicates the presence of mineralized uranium. U and Mo extraction efficiencies for most of the organic solvents studied were low and it appears that these elements are not occurring in significant amounts as low molecular weight organometallics. Humic acids have been separated into three M.W. tractions (110,000, 24,000, and 7,000 daltons) by gel filtration chromatography. The humic acids have also been separated into five molecular weight fractions (ranging from > 100,000 to < 1000) by ultrafiltration for the determination of the U and Mo distribution. The >100,000 M.W. fraction contained 78 percent of the U and the <1000 M.W. fraction contained 67 percent of the Mo. Sequential extraction of the lignite with HCl solutions ranging in pH from 3.0 to 0.7 produced a U extraction curve that is similar in shape to the acid dissociation curves of metal complexes. The good fit between curves for the first HCl lignite extraction and calculated pH dependent uranyl-humate extraction are consistent with an exchange between the uranyl ions and hydrogen ions at the humic acid sites. Calculations indicate that approximately 80 percent of the U is humically associated. Poorly crystalline uranium oxide minerals (possibly uraninite) were found in the >2.90 g/ml fraction of the low temperature ash by SEMEDS. These minerals appear to be precipitated onto clay particles. The uranium oxide minerals account for 10 to 20 percent of the U present in the lignite.

  11. Potential uses for the slag from the Cool Water demonstration plant: Final report

    SciTech Connect

    Deason, D.M.; Choudhry, V.

    1987-02-01

    Coal gasification processes produce waste materials which represent a significant expense in both disposal costs and real estate requirements. Other coal combustion wastes, such as fly ash, bottom ash, and boiler slag, are increasingly being used in construction applications. Similarly, there is considerable potential for utilizing coal gasification wastes, but to date very little evaluation has been carried out on these wastes. Praxis Engineers, Inc. prepared this report as part of an EPRI-sponsored study investigating the utilization potential of the gasification waste (slag) produced by the Cool Water facility, which uses integrated-gasification-combined-cycle (IGCC) technology. Basic chemical and physical properties of the slag were determined during this study. Its chemistry is quite similar to that of other coal combustion wastes, but its physical characteristics are considerably different due to the method of its formation, i.e., quenching of the molten mineral matter. On the basis of this work, sixteen potential applications were recommended for evaluation and show promise. The study also included evaluation of the utilization potential of the slag as a material for road construction and as a substitute for aggregate in cement concrete. However, before wider acceptance can be achieved larger-scale demonstration projects are required, both to overcome existing biases in favor of currently used materials, and to establish the economic competitiveness of the slag. 37 refs., 11 figs., 30 tabs.

  12. Removal of Gangue Minerals Containing Major Elements from Karlıova-Derinçay (Bingöl) Lignite Using a Reverse Flotation Method

    NASA Astrophysics Data System (ADS)

    Temel, Halime Abakay

    2015-12-01

    The removal of gangue minerals containing major elements was investigated using a reverse flotation method. Experiments were conducted on lignite samples, with high-ash and low-sulphur contents taken from a lignite field in Karlıova-Derinçay (Bingöl), Turkey. Predominant gangue minerals in the samples were found to be quartz, gypsum, feldspar minerals, mica minerals, and clays (smectite group). Preliminary flotation studies showed that gangue materials are more buoyant than the lignite sample. Some parameters that markedly influence the effectiveness of reverse flotation, such as grinding time, pH, collector type and volume, frother type and volume, and salt, were investigated. Quartz was found to cause a major problem in terms of reverse flotation. Flotation measurements showed that anionic collectors in an acidic medium result in the following element reduction order: sulphur trioxide > ferric oxide > magnesium oxide > calcium oxide > silicon dioxide > aluminium oxide.

  13. Understanding Slag Freeze Linings

    NASA Astrophysics Data System (ADS)

    Fallah-Mehrjardi, Ata; Hayes, Peter C.; Jak, Evgueni

    2014-09-01

    Slag freeze linings, the formation of protective deposit layers on the inner walls of furnaces and reactors, are increasingly used in industrial pyrometallurgical processes to ensure that furnace integrity is maintained in these aggressive, high-temperature environments. Most previous studies of freeze-linings have analyzed the formation of slag deposits based solely on heat transfer considerations. These thermal models have assumed that the interface between the stationary frozen layer and the agitated molten bath at steady-state deposit thickness consists of the primary phase, which stays in contact with the bulk liquid at the liquidus temperature. Recent experimental studies, however, have clearly demonstrated that the temperature of the deposit/liquid bath interface can be lower than the liquidus temperature of the bulk liquid. A conceptual framework has been proposed to explain the observations and the factors influencing the microstructure and the temperature of the interface at steady-state conditions. The observations are consistent with a dynamic steady state that is a balance between (I) the rate of nucleation and growth of solids on detached crystals in a subliquidus layer as this fluid material moves toward the stagnant deposit interface and (II) the dissolution of these detached crystals as they are transported away from the interface by turbulent eddies. It is argued that the assumption that the interface temperature is the liquidus of the bulk material represents only a limiting condition, and that the interface temperature can be between T liquidus and T solidus depending on the process conditions and bath chemistry. These findings have implications for the modeling approach and boundary conditions required to accurately describe these systems. They also indicate the opportunity to integrate considerations of heat and mass flows with the selection of melt chemistries in the design of future high temperature industrial reactors.

  14. Petrography and geochemistry of selected lignite beds in the Gibbons Creek mine (Manning Formation, Jackson Group, Paleocene) of east-central Texas

    USGS Publications Warehouse

    Warwick, P.D.; Crowley, S.S.; Ruppert, L.F.; Pontolillo, J.

    1997-01-01

    This study examined the petrographic and geochemical characteristics of two lignite beds (3500 and 4500 beds, Manning Formation, Jackson Group, Eocene) that are mined at the Gibbons Creek mine in east-central Texas. The purpose of the study was to identify the relations among sample ash yield, coal petrography, and trace-element concentrations in lignite and adjoining rock layers of the Gibbons Creek mine. Particular interest was given to the distribution of 12 environmentally sensitive trace elements (As, Be, Cd, Cr, Co, Hg, Mn, Ni, Pb, Sb, Se, and U) that have been identified as potentially hazardous air pollutants (HAPs) in the United States Clean Air Act Amendments of 1990. Eleven lignite, floor, and rock parting samples were collected from incremental channel samples of the 3500 and 4500 beds that were exposed in a highwall of pit A3 at the Gibbons Creek mine. Short proximate and ultimate and forms of sulfur analyses were performed on all lignite samples, and lignite and rock samples were analyzed for 60 major, minor and trace elements. Representative splits of all lignite samples were ground and cast into pellets, and polished for petrographic analyses in blue-light fluorescence and reflected white light to determine liptinite, inertinite, and huminite maceral group percentages. The following observations summarize our results and conclusions about the geochemistry, petrography, and sedimentology of the 3500 and 4500 beds of the Gibbons Creek lignite deposit: (1) Weighted average dry (db) ash yield for the two beds is 29.7%, average total sulfur content is 2.6%, and average calorific value is 7832 Btu (18.22 MJ/kg). Ash yields are greatest in the lower bench (59.33% db) of the 3500 bed and in the upper bench of the 4500 bed (74.61% db). (2) For lignite samples (on a whole-coal basis), the distributions of two of the HAPs (Pb and Sb) are positively related to ash yield, probably indicating an inorganic affinity for these elements. By using cluster analysis we

  15. Comparative studies of Eocene silicified peat and lignite: transition between peat and lignite

    SciTech Connect

    Ting, F.T.C.

    1985-01-01

    Silicified Eocene peats with excellent preserved cellular structures were found in lignite beds in western North Dakota and were comparatively studied. The well preserved plant tissues resemble that of modern Taxodium peat. The most striking difference between silicified peat and lignite is the disappearance of cell cavities when peat is transformed to lignite, a phenomenon caused primarily by compaction rather than cell wall swelling through humification or gelification. The differences between textinite and ulminite can be traced back to the differences between early wood and late wood of the secondary xylem. What appear to be cutinites in lignite are compressed cortex tissues of young plants. Silicified leaf and cortex tissues contain more visible fluorinite exhibiting brilliant fluorescence. Clustering phloem fibers or stone cells give rise to a material resembling resinite but are more akin to huminite A and/or suberinite. They converge to vitrinite when vitrinite reflectance exceeds 0.6%. Alternating banded phloem fibers and phloem parenchyma give rise to alternating layers of huminite A and huminite B. True micrinite does occur in lignite but in limited quantities.

  16. Fundamental Study of Low NOx Combustion Fly Ash Utilization

    SciTech Connect

    E. M. Suubert; I. Kuloats; K. Smith; N. Sabanegh; R.H. Hurt; W. D. Lilly; Y. M. Gao

    1997-05-01

    This study is principally concerned with characterizing the organic part of coal combustion fly ashes. High carbon fly ashes are becoming more common as by-products of low-NOx combustion technology, and there is need to learn more about this fraction of the fly ash. The project team consists of two universities, Brown and Princeton, and an electrical utility, New England Power. A sample suite of over forty fly ashes has been gathered from utilities across the United States, and includes ashes from a coals ranging in rank from bituminous to lignite. The characterizations of these ashes include standard tests (LOI, Foam Index), as well as more detailed characterizations of their surface areas, porosity, extractability and adsorption behavior. The ultimate goal is, by better characterizing the material, to enable broadening the range of applications for coal fly ash re-use beyond the current main market as a pozzolanic agent for concretes. The potential for high carbon-content fly ashes to substitute for activated carbons is receiving particular attention. The work performed to date has already revealed how very different the surfaces of different ashes produced by the same utility can be, with respect to polarity of the residual carbon. This can help explain the large variations in acceptability of these ashes as concrete additives.

  17. FUNDAMENTAL STUDY OF LOW-NOx COMBUSTION FLY ASH UTILIZATION

    SciTech Connect

    ERIC M. SUUBERG; ROBERT H. HURT

    1998-10-19

    This study is principally concerned with characterizing the organic part of coal combustion fly ashes. High carbon fly ashes are becoming more common as by-products of low-NOx combustion technology, and there is need to learn more about this fraction of the fly ash. The project team consists of two universities, Brown and Princeton, and an electrical utility, New England Power. A sample suite of over fifty fly ashes has been gathered from utilities across the United States, and includes ashes from a coals ranging in rank from bituminous to lignite. The characterizations of these ashes include standard tests (LOI, Foam Index), as well as more detailed characterizations of their surface areas, porosity, extractability and adsorption behavior. The ultimate goal is, by better characterizing the material, to enable broadening the range of applications for coal fly ash re-use beyond the current main market as a pozzolanic agent for concretes. The potential for high carbon-content fly ashes to substitute for activated carbons is receiving particular attention. The work performed to date has already revealed how very different the surfaces of different ashes produced by the same utility can be, with respect to polarity of the residual carbon. This can help explain the large variations in acceptability of these ashes as concrete additives.

  18. Fundamental Study of Low-Nox Combustion Fly Ash Utilization

    SciTech Connect

    E. M. Suuberg; I. Kuloats; K. Smith; N. Sabanegh; R. H. Hurt; W. D. Lilly; Y. M. Gao

    1997-11-01

    This study is principally concerned with characterizing the organic part of coal combustion fly ashes. High carbon fly ashes are becoming more common as by-products of low-NOx combustion technology, and there is need to learn more about this fraction of the fly ash. The project team consists of two universities, Brown and Princeton, and an electrical utility, New England Power. A sample suite of over forty fly ashes has been gathered from utilities across the United States, and includes ashes from a coals ranging in rank from bituminous to lignite. The characterizations of these ashes include standard tests (LOI, Foam Index), as well as more detailed characterizations of their surface areas, porosity, extractability and adsorption behavior. The ultimate goal is, by better characterizing the material, to enable broadening the range of applications for coal fly ash re-use beyond the current main market as a pozzolanic agent for concretes. The potential for high carbon-content fly ashes to substitute for activated carbons is receiving particular attention. The work performed to date has already revealed how very different the surfaces of different ashes produced by the same utility can be, with respect to polarity of the residual carbon. This can help explain the large variations in acceptability of these ashes as concrete additives.

  19. Rising from the ashes: Coal ash in recycling and construction

    SciTech Connect

    Naquin, D.

    1998-02-01

    Beneficial Ash Management (BAM, Clearfield, Pa.) has won an environmental award for its use of ash and other waste to fight acid mine drainage. The company`s workers take various waste materials, mainly fly ash from coal-burning plants, to make a cement-like material or grouting, says Ernest Roselli, BAM president. The grouting covers the soil, which helps prevent water from contacting materials. This, in turn, helps control chemical reactions, reducing or eliminating formation of acid mine drainage. The company is restoring the 1,400-acre Bark Camp coal mine site near Penfield in Clearfield County, Pa. Under a no-cost contract with the state of Pennsylvania, BAM is using boiler slag, causticizing byproducts (lime) and nonreclaimable clarifier sludge from International Paper Co. (Erie, Pa.). The mine reclamation techniques developed and monitored at the site include using man-made wetlands to treat acid mine drainage and testing anhydrous ammonia as a similar treatment agent. BAM researches and tests fly ash mixed with lime-based activators as fill material for land reclamation, and develops and uses artificial soil material from paper mill and tannery biosolids.

  20. Hydrothermal reactions of fly ash. Final report

    SciTech Connect

    Brown, P.W.

    1995-12-31

    The emphasis of the work done has been to determine the reactivities of two ashes believed to be representative of those generated. A bituminous ash and a lignitic ash have been investigated. The reactions of these ashes undergo when subjected to mild hydrothermal conditions were explored. The nature of the reactions which the ashes undergo when alkaline activators, calcium hydroxide and calcium sulfate are present was also investigated. It was determined that calcium silicate hydrate, calcium aluminate hydrate, and the calcium sulfoaluminate hydrate ettringite form under these conditions. It appears 3CaO{center_dot}Al{sub 2}O{sub 3}{center_dot}3CaSO{sub 4}{center_dot}32H{sub 2}O (ettringite) formation needs to be considered in ashes which contain significant amounts of sulfate. Therefore the stability region for ettringite was established. It was also determined that calcium silicate hydrate, exhibiting a high internal surface area, will readily form with hydrothermal treatment between 50{degrees} and 100{degrees}C. This phase is likely to have a significant capacity to take up heavy metals and oxyanions and this ability is being explored.

  1. Fly ash: Perspective resource for geo-polymer materials production

    NASA Astrophysics Data System (ADS)

    Kargin, Aleksey; Baev, Vladimir; Mashkin, Nikolay; Uglyanica, Andrey

    2016-01-01

    The present paper presents the information about the chemical and mineralogical composition of the ash and slag and their amounts at the dumps of the thermoelectric plants located in the city of Kemerovo. It is known that about 85% of ash and slag from the thermoelectric plants in Russia are removed by means of the hydraulic sluicing systems and only about 15% - by the systems of pneumatic ash handling. Currently, however, the transition from the "wet" ash removal systems to the "dry" ones is outlined. This process is quite logical since the fly ash has the higher reactivity compared with the hydraulic sluicing ash and therefore it is of the great interest for recycling and use. On the other hand, the recent trend is the increased use of fly ash in the production of geo-polymers due to their availability, workability and the increased life of the final product. The analysis is carried out to check the possibility of using the fly ash from various Kemerovo thermoelectric plants as a raw material for the production of the alkali-activated binder.

  2. NOx reduction in a lignite cyclone furnace

    SciTech Connect

    Melland, C.; O`Connor, D.

    1998-12-31

    Reburning, selective catalytic reduction, and selective noncatalytic reduction techniques have demonstrated some potential for NOx reduction in cyclone boilers. These techniques are costly in terms of both capital and operating costs. Lignite cyclone combustion modeling studies indicated that modifying combustion inside the cyclone barrel could reduce cyclone NOx emissions. The modeling showed that air staging, secondary air basing, flue gas injection and variations in coal moisture content could affect NOx emissions. Short term lignite boiler tests and now longer term boiler operation have confirmed that significant NOx reductions can be accomplished merely by modifying cyclone combustion. The low NOx operation does not appear to significantly impact maintenance, reliability or capacity of the cyclone burner or furnace.

  3. The spatial distribution of the lignite qualitative parameters and variant estimates of coal reserves: the Czech Part of the Vienna Basin

    NASA Astrophysics Data System (ADS)

    Jelínek, Jan; Staněk, František; Vebr, Lukáš; Honěk, Josef

    2014-06-01

    The aim of this article is to inform about the spatial distribution of the lignite qualitative parameters and total lignite reserves in the Czech Part of the Vienna Basin—The South Moravian Lignite Coalfield (SMLC). The total reserves were estimated on the basis of several composed variant digital models of individual seams in four partial area of SMLC. Calculations of the reserves resulted from the identified spatial distribution of chemical-technological parameters obtained from the thousands analysis of samples taken from more than 4,000 exploration works. The basic model of the deposit was so-called geological model characterising genetic evolution of the deposit and defines the spatial positions of the coal seams. Subsequently developed variant economical models spatially define the selected areas by the quality of lignite expressed by the limits of ash yield. Based on the created models, it was found that in the past just 3-7 % (depending on the variant model) of the total lignite reserves SMLC had been extracted. The presented geological reserves are currently using the existing mining technologies only partially mineable.

  4. (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.

  5. A Study on Suitability of EAF Oxidizing Slag in Concrete: An Eco-Friendly and Sustainable Replacement for Natural Coarse Aggregate.

    PubMed

    Sekaran, Alan; Palaniswamy, Murthi; Balaraju, Sivagnanaprakash

    2015-01-01

    Environmental and economic factors increasingly encourage higher utility of industrial by-products. The basic objective of this study was to identify alternative source for good quality aggregates which is depleting very fast due to fast pace of construction activities in India. EAF oxidizing slag as a by-product obtained during the process in steel making industry provides great opportunity to utilize it as an alternative to normally available coarse aggregates. The primary aim of this research was to evaluate the physical, mechanical, and durability properties of concrete made with EAF oxidizing slag in addition to supplementary cementing material fly ash. This study presents the experimental investigations carried out on concrete grades of M20 and M30 with three mixes: (i) Mix A, conventional concrete mix with no material substitution, (ii) Mix B, 30% replacement of cement with fly ash, and (iii) Mix C, 30% replacement of cement with fly ash and 50% replacement of coarse aggregate with EAF oxidizing slag. Tests were conducted to determine mechanical and durability properties up to the age of 90 days. The test results concluded that concrete made with EAF oxidizing slag and fly ash (Mix C) had greater strength and durability characteristics when compared to Mix A and Mix B. Based on the overall observations, it could be recommended that EAF oxidizing slag and fly ash could be effectively utilized as coarse aggregate replacement and cement replacement in all concrete applications. PMID:26421315

  6. A Study on Suitability of EAF Oxidizing Slag in Concrete: An Eco-Friendly and Sustainable Replacement for Natural Coarse Aggregate

    PubMed Central

    Sekaran, Alan; Palaniswamy, Murthi; Balaraju, Sivagnanaprakash

    2015-01-01

    Environmental and economic factors increasingly encourage higher utility of industrial by-products. The basic objective of this study was to identify alternative source for good quality aggregates which is depleting very fast due to fast pace of construction activities in India. EAF oxidizing slag as a by-product obtained during the process in steel making industry provides great opportunity to utilize it as an alternative to normally available coarse aggregates. The primary aim of this research was to evaluate the physical, mechanical, and durability properties of concrete made with EAF oxidizing slag in addition to supplementary cementing material fly ash. This study presents the experimental investigations carried out on concrete grades of M20 and M30 with three mixes: (i) Mix A, conventional concrete mix with no material substitution, (ii) Mix B, 30% replacement of cement with fly ash, and (iii) Mix C, 30% replacement of cement with fly ash and 50% replacement of coarse aggregate with EAF oxidizing slag. Tests were conducted to determine mechanical and durability properties up to the age of 90 days. The test results concluded that concrete made with EAF oxidizing slag and fly ash (Mix C) had greater strength and durability characteristics when compared to Mix A and Mix B. Based on the overall observations, it could be recommended that EAF oxidizing slag and fly ash could be effectively utilized as coarse aggregate replacement and cement replacement in all concrete applications. PMID:26421315

  7. Effects of Measurement Materials and Oxygen Partial Pressure on the Viscosity of synthetic Eastern and Western United States Coal Slags

    SciTech Connect

    Zhu, Jingxi; Tetsuya, Kenneth; Mu, Haoyuan; Bennett, James P.; Sridhar, Seetharaman

    2012-07-01

    The viscosity of the molten ash (slag) resulting from the mineral constituents in carbon feedstock used in slagging gasifiers is critical for controlling the gasification process. The viscosity of two synthetic slags with compositions resembling the mineral impurities in average eastern and western coal feedstock was examined at temperatures from 1300–1500 °C using a rotating bob viscometer. A few combinations of atmospheres and experimental materials were investigated with respect to one another to determine slag viscosity. A CO/CO{sub 2} atmosphere (CO/CO{sub 2} = 1.8, corresponding to a P{sub O{sub 2}} = 10–8 atm) is required to sustain ferrous ions in FeO-containing slags, an environment that is oxidizing to most metals. Iron oxide in the slag prevents usage of Fe parts. In unpurified Ar, the Fe metal surface oxidizes. Using purified argon prevents iron measurement components from oxidation; however, the metallic surfaces act as nucleation sites for the reduction of the Fe oxide in the slag into metallic Fe. Dissolution of ceramic materials into the slag, including Al{sub 2}O{sub 3} and ZrO{sub 2}, occurs in both atmospheres. Therefore, evaluating slag properties in the laboratory is challenging. The measured viscosities of two synthetic slags in this study diverged depending upon material selection. This difference is likely attributable to container/spindle-slag interactions. Viscosity measurements of the eastern coal slag using all ceramic parts agreed best with FactSage prediction above 1350 °C, with an average activation energy of 271.2 kJ. For western coal slag, the dissolution of container/spindle materials was substantial during the measurement, with precipitation of crystalline phase noted. The experimental viscosity data of the western coal slag agreed best with Kalmanovitch prediction above 1350 °C. The activation energy changed dramatically for both data sets of western coal slag, likely indicating the Newtonian-to-non-Newtonian transition.

  8. Investigation of coal char-slag transition during oxidation: effect of temperature and residual carbon

    SciTech Connect

    Suhui Li; Kevin J. Whitty

    2009-04-15

    The transition of coal char to molten slag at high conversion was studied for a bituminous coal using a laminar entrained-flow reactor under oxidizing conditions. Post-oxidized char particles were analyzed by various techniques including loss-on-ignition, gas adsorption analysis, and scanning electron microscopy to determine carbon content, internal surface area and pore size distribution, and char morphology, respectively. These analyses provide information concerning the effect of temperature and residual carbon on the transition from porous char to molten slag. Results showed that, at temperatures above the ash flow temperature, the transition from porous char to molten slag occurred at about 90% conversion for the coal used in this study. No transition occurred at temperatures below the ash flow temperature. This finding explains previous observations that there is a coal-dependent critical carbon conversion at which the ash stickiness increases dramatically. This result also indicates that surface area can be used as a criterion for determining the critical conversion of the transition. In addition, it was found that the randomly overlapping pore model cannot be directly applied to predict the surface area evolution of char particles during the transition without considering the reopening of closed micropores during the initial reaction and the ash fusion effect. 33 refs., 9 figs., 2 tabs.

  9. Preparation and combustion of Yugoslavian lignite-water fuel, Task 7.35. Topical report, July 1991--December 1993

    SciTech Connect

    Anderson, C.M.; DeWall, R.A.; Ljubicic, B.R.; Musich, M.A.; Richter, J.J.

    1994-03-01

    Yugoslavia`s interest in lignite-water fuel (LWF) stems from its involvement in an unusual power project at Kovin in northern Serbia. In the early 1980s, Electric Power of Serbia (EPS) proposed constructing a 600-MW power plant that would be fueled by lignite found in deposits along and under the Danube River. Trial underwater mining at Kovin proved that the dredging operation is feasible. The dredging method produces a coal slurry containing 85% to 90% water. Plans included draining the water from the coal, drying it, and then burning it in the pulverized coal plant. In looking for alternative ways to utilize the ``wet coal`` in a more efficient and economical way, a consortium of Yugoslavian companies agreed to assess the conversion of dredged lignite into a LWF using hot-water-drying (HWD) technology. HWD is a high-temperature, nonevaporative drying technique carried out under high pressure in water that permanently alters the structure of low-rank coals. Changes effected by the drying process include irreversible removal of moisture, micropore sealing by tar, and enhancement of heating value by removal of oxygen, thus, enhancement of the slurry ability of the coal with water. Physical cleaning results indicated a 51 wt % reduction in ash content with a 76 wt % yield for the lignite. In addition, physical cleaning produced a cleaned slurry that had a higher attainable solids loading than a raw uncleaned coal slurry. Combustion studies were then performed on the raw and physically cleaned samples with the resulting indicating that both samples were very reactive, making them excellent candidates for HWD. Bench-scale results showed that HWD increased energy densities of the two raw lignite samples by approximately 63% and 81%. An order-of-magnitude cost estimate was conducted to evaluate the HWD and pipeline transport of Kovin LWF to domestic and export European markets. Results are described.

  10. Environmental assessment of remedial action at the inactive uraniferous lignite processing sites at Belfield and Bowman, North Dakota. [UMTRA Project

    SciTech Connect

    Beranich, S.; Berger, N.; Bierley, D.; Bond, T.M.; Burt, C.; Caldwell, J.A.; Dery, V.A.; Dutcher, A.; Glover, W.A.; Heydenburg, R.J.; Larson, N.B.; Lindsey, G.; Longley, J.M.; Millard, J.B.; Miller, M.; Peel, R.C.; Persson-Reeves, C.H.; Titus, F.B.; Wagner, L.

    1989-09-01

    The Uranium Mill Tailings Radiation Control Act of 1978 (UMTRCA), to clean up the Belfield and Bowman, North Dakota, uraniferous lignite processing sites to reduce the potential health impacts associated with the residual radioactive materials remaining at these sites. Remedial action at these sites must be performed in accordance with the US Environmental Protection Agency's (EPA) standards promulgated for the remedial action and with the concurrence of the US Nuclear Regulatory Commission (NRC) and the state of North Dakota. The inactive Belfield uraniferous lignite processing site is one mile southeast of Belfield, North Dakota. The inactive Bowman uraniferous lignite processing site at the former town of Griffin, is seven miles northwest of Bowman, North Dakota and 65 road miles south of Belfield. Lignite ash from the processing operations has contaminated the soils over the entire 10.7-acre designated Belfield site and the entire 12.1-acre designated Bowman site. Dispersion of the ash has contaminated an additional 20.6 acres surrounding the Belfield processing site and an additional 59.2 acres surrounding the Bowman processing site. The proposed remedial action is to relocate the contaminated materials at the Belfield processing site to the Bowman processing/disposal site for codisposal with the Bowman contaminated soils. The environmental impacts assessed in this EA were evaluated for the proposed remedial action and the no action alternative and demonstrate that the proposed action would not significantly affect the quality of the human environment and would be performed in compliance with applicable environmental laws. The no action alternative would not be consistent with the intent of Public Law 95-604 and would not comply with the EPA standards. 48 refs., 10 figs., 7 tabs.

  11. Comparative Study on Synergetic Degradation of a Reactive Dye Using Different Types of Fly Ash in Combined Adsorption and Photocatalysis

    NASA Astrophysics Data System (ADS)

    Giri Babu, P. V. S.; Swaminathan, G.

    2016-07-01

    A comprehensive study was carried out on four different fly ashes used as a catalyst for the degradation of Acid Red 1 using ultraviolet rays. These fly ashes are collected from different thermal power stations located at various places in India and having different chemical compositions. Three fly ashes are from lignite-based thermal power plants, and one is from the coal-based power plant. One fly ash is classified as Class F, two fly ashes are classified as Class C and remaining one is not conforming to ASTM C618 classification. X-Ray Fluorescence analysis was used to identify the chemical composition of fly ashes and SiO2, Al2O3, CaO, Fe2O3 and TiO2 were found to be the major elements present in different proportions. Various analysis were carried out on all the fly ashes like Scanning Electron Microscopy to identify the microphysical properties, Energy Dispersive X-Ray spectroscopy to quantify the elements present in the catalyst and X-Ray Diffraction to identify the catalyst phase analysis. The radical generated during the reaction was identified by Electron paramagnetic resonance spectroscopy. The parameters such as initial pH of the dye solution, catalyst dosage and initial dye concentration which influence the dye degradation efficiency were studied and optimised. In 60 min duration, the dye degradation efficiency at optimum parametric values of pH 2.5, initial dye concentration of 10 mg/L and catalyst dosage of 1.0 g/L using various fly ashes, i.e., Salam Power Plant, Barmer Lignite Power Plant, Kutch Lignite Power Plant and Neyveli Lignite Thermal Power plant (NLTP) were found to be 40, 60, 67 and 95 % respectively. The contribution of adsorption alone was 18 % at the above mentioned optimum parametric values. Among the above four fly ash NLTP fly ashes proved to be most efficient.

  12. Development of improved performance refractory liner materials for slagging gasifiers

    SciTech Connect

    Kwong, Kyei-Sing; Bennett, James P.; Powell, Cynthia; Thomas, Hugh; Krabbe, Rick

    2005-01-01

    Refractory liners for slagging gasifiers used in power generation, chemical production, or as a possible future source of hydrogen for a hydrogen based economy, suffer from a short service life. These liner materials are made of high Cr2O3 and lower levels of Al2O3 and/or ZrO2. As a working face lining in the gasifier, refractories are exposed to molten slags at elevated temperature that originate from ash in the carbon feedstock, including coal and/or petroleum coke. The molten slag causes refractory failure by corrosion dissolution and by spalling. The Albany Research Center is working to improve the performance of Cr2O3 refractories and to develop refractories without Cr2O3 or with Cr2O3 content under 30 wt pct. Research on high Cr2O3 materials has resulted in an improved refractory with phosphate additions that is undergoing field testing. Results to date of field trials, along with research direction on refractories with no or low Cr2O3, will be discussed.

  13. Corrosion performance of ceramic materials in slagging environments

    SciTech Connect

    Natesan, K.

    1996-10-01

    Conceptual designs of advanced combustion systems that use coal as feedstock require high-temperature furnaces and heat transfer surfaces that can operate at temperatures much higher than in current coal-fired power plants. Combination of elevated temperatures and hostile combustion environments requires advanced ceramics. Objectives of this program are to evaluate the (a) chemistry of gaseous and condensed products arising during coal combustion, (b) corrosion behavior of candidate materials in air, slag, and salt environments, and (c)residual mechanical properties of the materials after corrosion. Temperatures in the range of 1000-1400 C for ceramics and 600-1000 C for metallic alloys are emphasized. Coal/ash chemistries developed on the basis of thermodynamic/kinetic calculations, together with slags from actual combustors, are used. Materials being evaluated include monolithic Si carbides from several sources: Si nitride, Si carbide in alumina composites, Si carbide fibers in a Si carbide-matrix composite, and some advanced Ni-base alloys. This paper presents results from an ongoing program on corrosion performance of candidate ceramic materials exposed to air, salt, and slag environments and their effect on flexural strength and energy absorbed during fracture of these materials. 10 figs, 4 tabs, 8 refs.

  14. Slag-based saltstone formulations

    SciTech Connect

    Langton, C.A.

    1987-08-01

    Approximately 400 x 10/sup 6/ L of low-level alkaline salt solution will be treated at the Savannah River Plant (SRP) Defense Waste Processing Facility (DWPF) prior to disposal in concrete vaults at SRP. Treatment involves removal of Cs/sup +/ and Sr/sup +2/, followed by solidification and stabilization of potential contaminants in saltstone, a hydrated ceramic wasteform. Chromium, technetium, and nitrate releases from saltstone can be significantly reduced by substituting hydraulic blast furnace slag for portland cement in the formulation designs. Slag-based mixes are also compatible with the Class F flyash used in saltstone as a functional extender to control heat of hydration and reduce permeability. (Class F flyash is also locally available at SRP.) A monolithic wasteform is produced by the hydration of the slag and flyash. Soluble ion release (NO/sup 3 -/) is controlled by the saltstone microstructure. Chromium and technetium are less leachable from slag mixes because these species are chemically reduced to a lower valence state by ferrous iron in the slag and are precipitated as relatively insoluble phases, such as Cr(OH)/sub 3/ and TcO/sub 2/. 3 refs., 3 figs., 2 tabs.

  15. Origin and significance of high nickel and chromium concentrations in pliocene lignite of the Kosovo Basin, Serbia

    USGS Publications Warehouse

    Ruppert, L.; Finkelman, R.; Boti, E.; Milosavljevic, M.; Tewalt, S.; Simon, N.; Dulong, F.

    1996-01-01

    Trace element data from 59 Pliocene lignite cores from the lignite field in the Kosovo Basin, southern Serbia, show localized enrichment of Ni and Cr (33-304 ppm and 8-176 ppm, respectively, whole-coal basis). Concentrations of both elements decrease from the western and southern boundaries of the lignite field. Low-temperature ash and polished coal pellets of selected bench and whole-coal samples were analyzed by X-ray diffraction and scanning electron microscopy with energy-dispersive X-ray analyses. These analyses show that most of the Ni and Cr are incorporated in detrital and, to a lesser degree, in authigenic minerals. The Ni- and Cr-bearing detrital minerals include oxides, chromites, serpentine-group minerals and rare mixed-layer clays. Possible authigenic minerals include Ni-Fe sulfates and sulfides. Analyses of three lignite samples by a supercritical fluid extraction technique indicate that some (1-11%) of the Ni is organically bound. Ni- and Cr-bearing oxides, mixed-layer clays, chromites and serpentine-group minerals were also identified in weathered and fresh samples of laterite developed on serpentinized Paleozoic peridotite at the nearby Glavica and C??ikatovo Ni mines. These mines are located along the western and northwestern rim, respectively, of the Kosovo Basin, where Ni contents are highest. The detrital Ni- and Cr-bearing minerals identified in lignite samples from the western part of the Kosovo Basin may have been transported into the paleoswamp by rivers that drained the two Paleocene laterites. Some Ni may have been transported directly into the paleoswamp in solution or, alternatively, Ni may have been leached from detrital minerals by acidic peat water and adsorbed onto organic matter and included into authigenic mineral phases. No minable source of Ni and Cr is known in the southern part of the lignite field; however, the mineral and chemical data from the lignite and associated rocks suggest that such a source area may exist.

  16. Slagging properties of coals and allowance for them in the analysis of the possibility of using out-of-design fuel

    SciTech Connect

    A.N. Alekhnovich; N.V. Artem'eva; V.V. Bogomolov

    2006-05-15

    It is shown that out-of-design coal should be used only after computational analysis of slagging of the boiler. The use of ash fusibility as a criterion for the analysis should be avoided because this property does not reflect the slagging properties of coal to an acceptable degree. Parameters characterizing the properties more appropriately are presented. It is shown that slagging of an actual furnace depends on many factors and the condition that 'the thermal stresses should be lower than the limiting value' is insufficient. An algorithm for the analysis is suggested on the basis of the slagging conditions arising upon transition from one kind of fuel to another with allowance for the actual slagging situation.

  17. Non traditional uses of coal ash: Steel industry applications

    SciTech Connect

    Hauke, D.

    1997-09-01

    Coal fly ash is used by the steel industry as an insulating cover to retain heat in ladles of molten steel and as a slag foamer in electric arc furnaces (EAFs) to prolong the life of consumable components and to aid extraction of impurities from the molten steel. The fly ashes that are used in the steel industry are generated from stoker boilers and have a relatively wide particle-size distribution. The powder-type materials used by steel mills to insulate ladles of molten metal include rice hull ash, a heat treated montmorillonite clay mineral (calcined clay), a fly ash from a stoker boiler called LadleJacket, and coke breeze. These ladle insulators should be flowable, coarse, and have a wide particle-size distribution. A study to compare the insulating characteristics of ladle insulators, conducted by the American Foundrymen`s Society Cast Metals Institute, indicated that the ladle insulated with LadleJacket exhibited a lower rate of heat loss than either the rice hull ash or calcined clay. To prolong the life of carbon electrodes and refractory in EAFs and to promote extraction of contaminants from the steel, carbon-based ingredients are injected into the slag to cause it to foam. Typically, high-carbon products such as coke breeze (coke fines) are used as slag foamers. A new product called Carbon Plus, which is a coarse, high-carbon fly ash from a coal-fired stoker boiler, is now being used as a slag foamer in the steel industry.

  18. INTEGRATED ASSESSMENT OF TEXAS LIGNITE DEVELOPMENT. VOLUME I. TECHNICAL ANALYSES

    EPA Science Inventory

    This report contains the results of a project to assess the probable impacts of expected future development of Texas lignite resources. This multi-disciplinary, policy-oriented study considered possible lignite extraction and utilization options through the year 2000. The researc...

  19. Characterization of microbes which polymerize and depolymerize lignite coals

    SciTech Connect

    Polman, J.K.; Breckenridge, C.R.; Quigley, D.R.

    1991-01-01

    Several bacteria were tested for their ability to modify the macromolecular structure of different coals. When grown in the presence of Mississippi Wilcox lignite, North Dakota Beulah Zap lignite, and North Dakota lenoardite, strain Con5-1L produces polymerization products that are derived from coal. This bacterium was characterized extensively with respect to physiology and morphology and may be a member of the genus Arthrobacter. Strain UPLCPS2-B, which was identified as Pseudomonas chlororaphis, may be capable of limited depolymerization of Mississippi Wilcox lignite and leonardite, but not Beulah Zap lignite. Fermentative strain Con5-5C, which may extensively depolymerize Mississippi Wilcox lignite, was characterized according to morphology and physiology. Other strains tested had little or no effect on coal macromolecular structure. These included Escherichia coli, Arthrobacter paraffineus, and strain BED1. 21 refs., 2 figs.

  20. Characterization of microbes which polymerize and depolymerize lignite coals

    SciTech Connect

    Polman, J.K.; Breckenridge, C.R.; Quigley, D.R.

    1991-12-01

    Several bacteria were tested for their ability to modify the macromolecular structure of different coals. When grown in the presence of Mississippi Wilcox lignite, North Dakota Beulah Zap lignite, and North Dakota lenoardite, strain Con5-1L produces polymerization products that are derived from coal. This bacterium was characterized extensively with respect to physiology and morphology and may be a member of the genus Arthrobacter. Strain UPLCPS2-B, which was identified as Pseudomonas chlororaphis, may be capable of limited depolymerization of Mississippi Wilcox lignite and leonardite, but not Beulah Zap lignite. Fermentative strain Con5-5C, which may extensively depolymerize Mississippi Wilcox lignite, was characterized according to morphology and physiology. Other strains tested had little or no effect on coal macromolecular structure. These included Escherichia coli, Arthrobacter paraffineus, and strain BED1. 21 refs., 2 figs.

  1. Vitrification of MSWI Fly Ash by Thermal Plasma Melting and Fate of Heavy Metals

    NASA Astrophysics Data System (ADS)

    Ni, Guohua; Zhao, Peng; Jiang, Yiman; Meng, Yuedong

    2012-09-01

    Municipal solid waste incinerator (MSWI) fly ash with high basicity (about 1.68) was vitrified in a thermal plasma melting furnace system. Through the thermal plasma treatment, the vitrified product (slag) with amorphous dark glassy structure was obtained, and the leachability of hazardous metals in slag was significantly reduced. Meanwhile, it was found that the cooling rate affects significantly the immobility of heavy metals in slag. The mass distribution of heavy metals (Zn, Cd, Cr, Pb, As, Hg) was investigated in residual products (slag, secondary residues and flue gas), in order to analyze the behavior of heavy metals in thermal plasma atmosphere. Heavy metal species with low boiling points accounting for the major fraction of their input-mass were adsorbed in secondary residues by pollution abatement devices, while those with high boiling points tended to be encapsulated in slag.

  2. Control methods for mitigating biomass ash-related problems in fluidized beds.

    PubMed

    Vamvuka, D; Zografos, D; Alevizos, G

    2008-06-01

    Embodiment of biomass combustion technologies in the Cretan energy system will play an important role and will contribute to the local development. The main biomass fuels of Crete are the agricultural residues olive kernel and olive tree wood. Future applications of these biofuels may create, among others, operational problems related to ash effects. In this regard, the thermal behavior of the ashes during lab-scale fluidized bed combustion tests was examined, in terms of slagging/fouling and agglomeration of bed material. Control methodologies for mitigating ash problems were applied, such as leaching the raw fuels with water and using different mineral additives during combustion. The ashes and the bed material were characterized in terms of mineralogical, chemical and morphological analyses and the slagging/fouling and agglomeration propensities were determined. The results showed that fly ashes were rich in Ca, Si and Fe minerals and contained substantial amounts of alkali, falling within the range of "certain or probable slagging/fouling". Leaching of the raw fuels with water resulted in a significant reduction of the problematic elements K, Na, Cl and S in the fly ashes. The use of fuel additives decreased the concentrations of alkali and iron minerals in the fly ashes. With clay additives calcium compounds were enriched in the bottom ash, while with carbonate additives they were enriched in the fly ash. Fuel additives or water leaching reduced the slagging/fouling potential due to alkali. Under the conditions of the combustion tests, no signs of ash deposition or bed agglomeration were noticed. PMID:17826986

  3. Optical properties of fly ash. Volume 1, Final report

    SciTech Connect

    Self, S.A.

    1994-12-01

    Research performed under this contract was divided into four tasks under the following headings: Task 1, Characterization of fly ash; Task 2, Measurements of the optical constants of slags; Task 3, Calculations of the radiant properties of fly ash dispersions; and Task 4, Measurements of the radiant properties of fly ash dispersions. Tasks 1 and 4 constituted the Ph.D. research topic of Sarbajit Ghosal, while Tasks 2 and 3 constituted the Ph.D. research topic of Jon Ebert. Together their doctoral dissertations give a complete account of the work performed. This final report, issued in two volumes consists of an executive summary of the whole program followed by the dissertation of Ghosal. Volume 1 contains the dissertation of Ghosal which covers the characterization of fly ash and the measurements of the radiant properties of fly ash dispersions. A list of publications and conference presentations resulting from the work is also included.

  4. Preliminary results from field testing an improved refractory material for slagging coal gasifiers

    SciTech Connect

    Bennett, James P.; Kwong, Kyei-Sing; Powell, Cynthia A.

    2004-01-01

    Slag attack of refractory materials used to line the hot face of slagging gasifiers limits their service life to between 3 and 24 months. These gasifiers use coal, petroleum coke, or combinations of them as raw materials to produce chemicals, liquid fuel, and/or electricity; with future consideration being given to the use of other abundant, low cost feedstock such as biomass. The ash from these materials generate liquid slags during gasification at temperature between 1300 - 1575 C and pressures up to 1000 psi, leading to severe slag attack of a vessel lining and causing unacceptable gasifier reliability and on-line availability. To maximize refractory life and provide protection of the gasifier metal shell, the best liners have contained a minimum of 60-70 pct chromia in combination with alumina, alumina/zirconia, or magnesia. The Albany Research Center of DOE has developed a phosphate containing high chrome oxide refractory liner that indicates potential for increased service life over currently used materials. This new liner has been produced commercially by a refractory company and installed in a gasifier for performance evaluation. Refractory issues in slagging gasifiers, the development and properties of the phosphate containing high chrome oxide material, and the preliminary results from the plant trial of this material will be presented.

  5. Construction material properties of slag from the high temperature arc gasification of municipal solid waste.

    PubMed

    Roessler, Justin G; Olivera, Fernando D; Wasman, Scott J; Townsend, Timothy G; McVay, Michael C; Ferraro, Christopher C; Blaisi, Nawaf I

    2016-06-01

    Slag from the high temperature arc gasification (HTAG) of municipal solid waste (MSW) was tested to evaluate its material properties with respect to use as a construction aggregate. These data were compared to previously compiled values for waste to energy bottom ash, the most commonly produced and beneficially used thermal treatment residue. The slag was tested using gradations representative of a base course and a course aggregate. Los Angeles (LA) abrasion testing demonstrated that the HTAG slag had a high resistance to fracture with a measured LA loss of 24%. Soundness testing indicated a low potential for reactivity and good weathering resistance with a mean soundness loss of 3.14%. The modified Proctor compaction testing found the slag to possess a maximum dry density (24.04kN/m(3)) greater than conventionally used aggregates and WTE BA. The LBR tests demonstrated a substantial bearing capacity (>200). Mineralogical analysis of the HTAG suggested the potential for self cementing character which supports the elevated LBR results. Preliminary material characterization of the HTAG slag establishes potential for beneficial use; larger and longer term studies focusing on the material's possibility for swelling and performance at the field scale level are needed. PMID:27020344

  6. Immobilization of antimony waste slag by applying geopolymerization and stabilization/solidification technologies.

    PubMed

    Salihoglu, Güray

    2014-11-01

    During the processing of antimony ore by pyrometallurgical methods, a considerable amount of slag is formed. This antimony waste slag is listed by the European Union as absolutely hazardous waste with a European Waste Catalogue code of 10 08 08. Since the levels of antimony and arsenic in the leachate of the antimony waste slag are generally higher than the landfilling limits, it is necessary to treat the slag before landfilling. In this study, stabilization/solidification and geopolymerization technologies were both applied in order to limit the leaching potential of antimony and arsenic. Different combinations ofpastes by using Portland cement, fly ash, clay, gypsum, and blast furnace slag were prepared as stabilization/solidification or geopoljymer matrixes. Sodium silicate-sodium hydroxide solution and sodium hydroxide solution at 8 M were used as activators for geopolymer samples. Efficiencies of the combinations were evaluated in terms of leaching and unconfined compressive strength. None of the geopolymer samples prepared with the activators yielded arsenic and antimony leaching below the regulatory limit at the same time, although they yielded high unconfined compressive strength levels. On the other hand, the stabilization/solidification samples prepared by using water showed low leaching results meeting the landfilling criteria. Use of gypsum as an additive was found to be successful in immobilizing the arsenic and antimony. PMID:25509550

  7. Leaching and toxicity behavior of coal-biomass waste cocombustion ashes

    SciTech Connect

    Skodras, G.; Prokopidou, M.; Sakellaropoulos, G.P.

    2006-08-15

    Land disposal of ash residues, obtained from the cocombustion of Greek lignite with biomass wastes, is known to create problems due to the harmful constituents present. In this regard, the leachability of trace elements from lignite, biomass, and blends cocombustion ashes was investigated by using the Toxicity Characteristic Leaching Procedure (TCLP) of the US Environmental Protection Agency (US EPA). In this work, the toxicity of the aqueous leachates and the concentrations of the metals obtained from the leaching procedure were measured using the Microtox test (Vibrio fischen) and inductive coupled plasma-atomic emission spectrometer (ICP-AES), respectively. The toxic effects of most leachates on Vibrio fischeri were found to be significantly low in both 45% and 82% screening test protocols. However, the liquid sample originating from olive kernels fly ash (FA4) caused the highest toxic effect in both protocols, which can be attributed to its relatively high concentrations of As, Cd, Co, Cu, Mn, Ni, and Zn.

  8. Leaching and toxicity behavior of coal-biomass waste cocombustion ashes.

    PubMed

    Skodras, G; Prokopidou, M; Sakellaropoulos, G P

    2006-08-01

    Land disposal of ash residues, obtained from the cocombustion of Greek lignite with biomass wastes, is known to create problems due to the harmful constituents present. In this regard, the leachability of trace elements from lignite, biomass, and blends cocombustion ashes was investigated by using the Toxicity Characteristic Leaching Procedure (TCLP) of the US Environmental Protection Agency (US EPA). In this work, the toxicity of the aqueous leachates and the concentrations of the metals obtained from the leaching procedure were measured using the Microtox test (Vibrio fischeri) and inductive coupled plasma-atomic emission spectrometer (ICP-AES), respectively. The toxic effects of most leachates on Vibrio fischeri were found to be significantly low in both 45% and 82% screening test protocols. However, the liquid sample originating from olive kernels fly ash (FA4) caused the highest toxic effect in both protocols, which can be attributed to its relatively high concentrations of As, Cd, Co, Cu, Mn, Ni, and Zn. PMID:16841309

  9. Utilization of lightweight materials made from coal gasification slags. Quarterly report, March 1995--May 1995

    SciTech Connect

    1995-06-01

    Integrated-gasification combined-cycle (IGCC) technology is an emerging technology that utilizes coal for power generation and production of chemical feedstocks. However, this process generates large amounts of solid waste, consisting of vitrified ash (slag) along with some unconverted carbon, which is disposed of as solid waste. In previous projects, Praxis investigated the utilization of {open_quotes}as-generated{close_quotes} slags for a wide variety of applications in road construction, cement and concrete production, agricultural applications, and as a landfill material. From these studies, we found that it would be extremely difficult for {open_quotes}as-generated{close_quotes} slag to find large-scale acceptance in the marketplace even at no cost because the materials it could replace were abundantly available at very low cost. It became apparent that a more promising approach would be to develop a variety of value-added products from slag that meet specific industry requirements. This approach was made feasible by the discovery that slag could be made into a lightweight material by controlled heating in a kiln at temperatures between 1400 and 1700{degrees}F. These results indicated the potential for using such materials as substitutes for conventional lightweight aggregates (LWA). The technology to produce lightweight and ultra-lightweight aggregates (ULWA) from slag was subsequently developed by Praxis with funding from the Electric Power Research Institute (EPRI), Illinois Clean Coal Institute (ICCI), and internal resources. The major objectives of the subject project, funded by DOE`s Morgantown Energy Technology Center (METC), are to demonstrate the technical and economic viability of commercial production of LWA and ULWA from slag and to test the suitability of these aggregates for various applications.

  10. COAL-FIRED UTILITY BOILERS: SOLVING ASH DEPOSITION PROBLEMS

    SciTech Connect

    Christopher J. Zygarlicke; Donald P. McCollor; Steven A. Benson; Jay R. Gunderson

    2001-04-01

    The accumulation of slagging and fouling ash deposits in utility boilers has been a source of aggravation for coal-fired boiler operators for over a century. Many new developments in analytical, modeling, and combustion testing methods in the past 20 years have made it possible to identify root causes of ash deposition. A concise and comprehensive guidelines document has been assembled for solving ash deposition as related to coal-fired utility boilers. While this report accurately captures the current state of knowledge in ash deposition, note that substantial research and development is under way to more completely understand and mitigate slagging and fouling. Thus, while comprehensive, this document carries the title ''interim,'' with the idea that future work will provide additional insight. Primary target audiences include utility operators and engineers who face plant inefficiencies and significant operational and maintenance costs that are associated with ash deposition problems. Pulverized and cyclone-fired coal boilers are addressed specifically, although many of the diagnostics and solutions apply to other boiler types. Logic diagrams, ash deposit types, and boiler symptoms of ash deposition are used to aid the user in identifying an ash deposition problem, diagnosing and verifying root causes, determining remedial measures to alleviate or eliminate the problem, and then monitoring the situation to verify that the problem has been solved. In addition to a step-by-step method for identifying and remediating ash deposition problems, this guideline document (Appendix A) provides descriptions of analytical techniques for diagnostic testing and gives extensive fundamental and practical literature references and addresses of organizations that can provide help in alleviating ash deposition problems.

  11. Utilization of lightweight materials made from coal gasification slags. Quaterly report, March 1, 1997--May 30, 1997

    SciTech Connect

    1998-12-31

    The integrated-gasification combined-cycle (IGCC) process is an emerging technology that utilizes coal for power generation and production of chemical feedstocks. However, the process generates large amounts of solid waste, consisting of vitrified ash (slag) and some unconverted carbon. In previous projects, Praxis investigated the utilization of {open_quotes}as-generated{close_quotes} slags for a wide variety of applications in road construction, cement and concrete production, agricultural applications, and as a landfill material. From these studies, we found that it would be extremely difficult for {open_quotes}as-generated{close_quotes} slag to find large-scale acceptance in the marketplace even at no cost because the materials it could replace were abundantly available at very low cost. It was further determined that the unconverted carbon, or char, in the slag is detrimental to its utilization as sand or fine aggregate. It became apparent that a more promising approach would be to develop a variety of value-added products from slag that meet specific industry requirements. This approach was made feasible by the discovery that slag undergoes expansion and forms a lightweight material when subjected to controlled heating in a kiln at temperatures between 1400 and 1700{degrees}F. These results confirmed the potential for using expanded slag as a substitute for conventional lightweight aggregates (LWA). The technology to produce lightweight and ultra-lightweight aggregates (ULWA) from slag was subsequently developed by Praxis with funding from the Electric Power Research Institute (EPRI), Illinois Clean Coal Institute (ICCI), and internal resources. The major objectives of the subject project are to demonstrate the technical and economic viability of commercial production of LWA and ULWA from slag and to test the suitability of these aggregates for various applications.

  12. Utilization of lightweight materials made from coal gasification slags. Quaterly report, December 1, 1996--February 28, 1997

    SciTech Connect

    1998-12-31

    Integrated-gasification combined-cycle (IGCC) technology is an emerging technology that utilizes coal for power generation and production of chemical feedstocks. However, the process generates large amounts of solid waste, consisting of vitrified ash (slag) and some unconverted carbon. In previous projects, Praxis investigated the utilization of {open_quotes}as-generated{close_quotes} slags for a wide variety of applications in road construction, cement and concrete production, agricultural applications, and as a landfill material. From these studies, we found that it would be extremely difficult for {open_quotes}as-generated{close_quotes} slag to find large-scale acceptance in the marketplace even at no cost because the materials it could replace were abundantly available at very low cost. It was further determined that the unconverted carbon, or char, in the slag is detrimental to its utilization as sand or fine aggregate. It became apparent that a more promising approach would be to develop a variety of value-added products from slag that meet specific industry requirements. This approach was made feasible by the discovery that slag undergoes expansion and forms a lightweight material when subjected to controlled heating in a kiln at temperatures between 1400 and 1700{degrees}F. These results confirmed the potential for using expanded slag as a substitute for conventional lightweight aggregates (LWA). The technology to produce lightweight and ultra-lightweight aggregates (ULWA) from slag was subsequently developed by Praxis with funding from the Electric Power Research Institute (EPRI), Illinois Clean Coal Institute (ICCI), and internal resources. The major objectives of the subject project are to demonstrate the technical and economic viability of commercial production of LWA and ULWA from slag and to test the suitability of these aggregates for various applications.

  13. Trace elements in the lignite-bearing area of Lofoi, Florina basin, Western Greek Macedonia, Greece

    SciTech Connect

    Pentari, D.; Foscolos, A.E.; Perdikatsis, V.

    2008-07-01

    Drill core samples of two boreholes from the Lofoi lignite-bearing area of Miocene-Pliocene age were analyzed for their trace element contents. The methods used were Instrumental Neutron Activation Analysis (INAA), Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-AES), and Atomic Absorption Spectroscopy (AAS). The results showed that all studied elements occur in concentrations within the reported ones for different coal-bearing basins of Greece. The elements Co, U, Sb, Th, Cs, As, Li, Mo, Y, Cu, Ni, Cr, Pb, Yb, Be, Rb, V, and Lu are enriched in the ashes when compared to their average concentration on the Earth's crust. The enrichment of elements encountered in silicic rocks as well as mafic and ultramafic rocks implies that there are two different types of rocks influencing the formation of the lignite deposit. Very strong to intermediate correlation is observed for the REE as well as for the elements Mo with As, Cu with Sb, Sc with Ni, Co, and V, and Rb with Ga, which is expected for these elements. Intermediate to strong positive correlation is also observed for the elements Th with Zn, Y with Be, Cr with As, Sb with Yb, As with Y, Zn with both Yb and Eu, as well as Cu with Th; this could only be attributed to the hypothesis that both silisic and mafic-ultramafic rocks influenced the formation of the deposit.

  14. Simulation of 0.3 MWt AFBC test rig burning Turkish lignites

    SciTech Connect

    Selcuk, N.; Degirmenci, E.; Oymak, O.

    1997-12-31

    A system model coupling bed and freeboard models for continuous combustion of lignite particles of wide size distribution burning in their own ash in a fluidized bed combustor was modified to incorporate: (1) a procedure for faster computation of particle size distributions (PSDs) without any sacrifice in accuracy; (2) energy balance on char particles for the determination of variation of temperature with particle size, (3) plug flow assumption for the interstitial gas. An efficient and accurate computer code developed for the solution of the conservation equations for energy and chemical species was applied to the prediction of the behavior of a 0.3 MWt AFBC test rig burning low quality Turkish lignites. The construction and operation of the test rig was carried out within the scope of a cooperation agreement between Middle East Technical University (METU) and Babcock and Wilcox GAMA (BWG) under the auspices of Canadian International Development Agency (CIDA). Predicted concentration and temperature profiles and particle size distributions of solid streams were compared with measured data and found to be in reasonable agreement. The computer code replaces the conventional numerical integration of the analytical solution of population balance with direct integration in ODE form by using a powerful integrator LSODE (Livermore Solver for Ordinary Differential Equations) resulting in two orders of magnitude decrease in CPU (Central Processing Unit) time.

  15. Influence of lignite mining and utilization on organic matter budget in the Alfeios River Plain, Peloponnese (South Greece)

    SciTech Connect

    G. Siavalas; S. Kalaitzidis; G. Cornelissen; A. Chatziapostolou; K. Christanis

    2007-09-15

    The Megalopolis Lignite Centre (MLC) is a lignite mining and power generation complex located in Southern Greece. In the present study, we investigate the influence of mining and combustion activities on the organic matter (OM) budget of the adjacent Alfeios River plain sediments. A total of 28 plain-sediment samples along with 13 lignite and ash samples from the MLC were collected. The sediment samples were collected from sites upstream and downstream, as well as from the vicinity of the MLC. Their OM and total organic carbon contents range from 0.9 to 43.4 and 0.2 to 24.0 wt %, respectively. The particulate OM was classified in coal-derived, carbonized particles and fresh tissues according to its origin. The different OM phases were quantified using maceral analysis on the sediments' light fraction obtained after heavy media separations. Approximately 75 vol % of the OM was of anthropogenic origin (coal and char particles) related to mining, transport, and combustion processes at the MLC, revealing a high contamination degree. The most contaminated sites were those in the vicinity of the MLC, but upstream and downstream sites also proved to contain high concentrations of anthropogenic OM. The polycyclic aromatic hydrocarbons content of the same sediments was very low, similar to pristine areas indicating that there is no contamination from such compounds in the area. 82 refs., 7 figs., 6 tabs.

  16. Recycling of Malaysia's electric arc furnace (EAF) slag waste into heavy-duty green ceramic tile.

    PubMed

    Teo, Pao-Ter; Anasyida, Abu Seman; Basu, Projjal; Nurulakmal, Mohd Sharif

    2014-12-01

    Recently, various solid wastes from industry such as glass waste, fly ash, sewage sludge and slag have been recycled into various value-added products such as ceramic tile. The conventional solutions of dumping the wastes in landfills or incineration, including in Malaysia are getting obsolete as the annual huge amount of the solid wastes would boost-up disposal cost and may cause permanent damage to the flora and fauna. This recent waste recycling approach is much better and greener as it can resolve problems associated with over-limit storage of industrial wastes and reduce exploration of natural resources for ceramic tile to continuously sustain the nature. Therefore, in this project, an attempt was made to recycle electric arc furnace (EAF) slag waste, obtained from Malaysia's steel making industry, into ceramic tile via conventional powder compaction method. The research work was divided into two stages. The first stage was to evaluate the suitability of EAF slag in ceramic tile by varying weight percentage of EAF slag (40 wt.%, 50 wt.% and 60 wt.%) and ball clay (40 wt.%, 50 wt.% and 60 wt.%), with no addition of silica and potash feldspar. In the second stage, the weight percentage of EAF slag was fixed at 40 wt.% and the percentage of ball clay (30 wt.% and 40 wt.%), feldspar (10 wt.% and 20 wt.%) and silica (10 wt.% and 20 wt.%) added was varied accordingly. Results obtained show that as weight percentage of EAF slag increased up to 60 wt.%, the percentage of apparent porosity and water absorption also rose, with a reduction in tile flexural strength and increased porosity. On the other hand, limiting the weight percentage of EAF slag to 40 wt.% while increasing the weight percentage of ball clay led to a higher total percentage of anorthite and wollastonite minerals, resulting in higher flexural strength. It was found that introduction of silica and feldspar further improved the flexural strength due to optimization of densification process. The highest

  17. Relationships proximate analysis results and higher heating values of lignites

    SciTech Connect

    Demirbas, A.

    2008-07-01

    In this study, the higher heating values (HHVs) of 26 lignite samples were calculated by using the proximate and elemental analyses data. The proximate analysis results such as volatile materials (VM), fixed carbon (FC) and HHV and the elemental analysis results such as carbon, hydrogen (H), oxygen (O), nitrogen (N) and sulfur (S) were determined for 26 lignite samples from different areas of Turkey. The lignite samples have been tested with particle size of 0-0.05 mm. The HHVs of 26 lignite samples obtained from different Turkish sources were determined experimentally and calculated from both ultimate and proximate analyses. HHVs of 26 the lignite samples can be calculated from the equation based modeling. The HHVs (MJ/kg) of the lignite samples as a function of fixed carbon (FC, wt%) or volatile materials (VM, %) was calculated from the following equations: HHV = 0.300FC + 11.117 (1) HHV = -0.323VM + 42.223 (2) where the correlation coefficients for Eqs. (1) and (2) were 0.9907 and 0.9862, respectively. The combustion heats calculated from Eqs. (1) and (2) showed mean differences of +3.9% and +0.3%, respectively. The HHVs (MJ/kg) of the lignite samples as a function of C, H, O, N, and S were calculated from a given equation where the correlation coefficients for the equation was 0.9891. HHVs calculated from this equation showed a mean deviation of +0.1.

  18. Nitrogen incorporation into lignite humic acids during microbial degradation

    SciTech Connect

    Dong, L.H.; Yuan, H.L.

    2009-07-01

    Previous study showed that nitrogen content in lignite humic acids (HA) increased significantly during lignite biodegradation. In this paper we evaluated the factors responsible for the increased level of N in HA and the formation of new nitrogen compound following microbial degradation. When the ammonium sulfate concentration in lignite medium was 0.5%, the N-content in HA was higher than that in the crude lignite humic acid (cHA); when the ammonium sulfate concentration was epsilon 0.5%, both the biodegraded humic acid (bHA) N-content and the content of bHA in lignite increased significantly, but at 2.0% no increase was observed. This indicated that HA incorporated N existing in the lignite medium, and more HA can incorporate more N with the increase of bHA amount in lignite during microbial degradation. CP/MAS {sup 15}N NMR analysis showed that the N incorporated into HA during biotransformation was in the form of free or ionized NH{sub 2}-groups in amino acids and sugars, as well as NH{sub 4}{sup +}. We propose nitrogen can be incorporated into HA biotically and abiotically. The high N content bHA has a potential application in agriculture since N is essential for plant growth.

  19. Emissions estimation for lignite-fired power plants in Turkey

    SciTech Connect

    Nurten Vardar; Zehra Yumurtaci

    2010-01-15

    The major gaseous emissions (e.g. sulfur dioxide, nitrogen oxides, carbon dioxide, and carbon monoxide), some various organic emissions (e.g. benzene, toluene and xylenes) and some trace metals (e.g. arsenic, cobalt, chromium, manganese and nickel) generated from lignite-fired power plants in Turkey are estimated. The estimations are made separately for each one of the thirteen plants that produced electricity in 2007, because the lignite-fired thermal plants in Turkey are installed near the regions where the lignite is mined, and characteristics and composition of lignite used in each power plant are quite different from a region to another. Emission factors methodology is used for the estimations. The emission factors obtained from well-known literature are then modified depending on local moisture content of lignite. Emission rates and specific emissions (per MWh) of the pollutants from the plants without electrostatic precipitators and flue-gas desulfurization systems are found to be higher than emissions from the plants having electrostatic precipitators and flue -gas desulfurization systems. Finally a projection for the future emissions due to lignite-based power plants is given. Predicted demand for the increasing generation capacity based on the lignite-fired thermal power plant, from 2008 to 2017 is around 30%. 39 refs., 13 figs., 10 tabs.

  20. JV Task 117 - Impact of Lignite Properties on Powerspan's NOx Oxidation System

    SciTech Connect

    Scott Tolbert; Steven Benson

    2008-02-29

    Powerspan's multipollutant control process called electrocatalytic oxidation (ECO) technology is designed to simultaneously remove SO{sub 2}, NO{sub x}, PM{sub 2.5}, acid gases (such as hydrogen fluoride [HF], hydrochloric acid [HCl], and sulfur trioxide [SO{sub 3}]), Hg, and other metals from the flue gas of coal-fired power plants. The core of this technology is a dielectric barrier discharge reactor composed of cylindrical quartz electrodes residing in metal tubes. Electrical discharge through the flue gas, passing between the electrode and the tube, produces reactive O and OH radicals. The O and OH radicals react with flue gas components to oxidize NO to NO{sub 2} and HNO{sub 3} and a small portion of the SO{sub 2} to SO{sub 3} and H{sub 2}SO{sub 4}. The oxidized compounds are subsequently removed in a downstream scrubber and wet electrostatic precipitator. A challenging characteristic of selected North Dakota lignites is their high sodium content. During high-sodium lignite combustion and gas cooling, the sodium vaporizes and condenses to produce sodium- and sulfur-rich aerosols. Based on past work, it was hypothesized that the sodium aerosols would deposit on and react with the silica electrodes and react with the silica electrodes, resulting in the formation of sodium silicate. The deposit and reacted surface layer would then electrically alter the electrode, thus impacting its dielectric properties and NO{sub x} conversion capability. The purpose of this project was to determine the impact of lignite-derived flue gas containing sodium aerosols on Powerspan's dielectric barrier discharge (DBD) reactor with specific focus on the interaction with the quartz electrodes. Partners in the project were Minnkota Power Cooperative; Basin Electric Power Cooperative; Montana Dakota Utilities Co.; Minnesota Power; the North Dakota Industrial Commission, the Lignite Energy Council, and the Lignite Research Council; the Energy & Environmental Research Center (EERC); and

  1. ²²⁶Ra, ²³²Th and ⁴⁰K radionuclides enhancement rate and dose assessment for residues of lignite-fired thermal power plants in Turkey.

    PubMed

    Parmaksiz, A; Arikan, P; Vural, M; Yeltepe, E; Tükenmez, I

    2011-11-01

    A total of 77 coal, slag and fly ash samples collected from six thermal power plants were measured by gamma-ray spectrometry. The average (226)Ra activity concentrations in coal, slag and fly ash were measured as 199.8±16.7, 380.3±21.8 and 431.5±29.0 Bq kg(-1), respectively. The average (232)Th activity concentrations in coal, slag and fly ash were measured as 32.0±2.4, 74.0±9.0 and 87.3±9.8 Bq kg(-1), respectively. The average (40)K activity concentrations in coal, slag and fly ash were found to be 152.8±12.1, 401.3±25.0 and 439.0±30.2 Bq kg(-1), respectively. The radium equivalent activities of samples varied from 147.6±8.5 to 1077.4±53.3 Bq kg(-1). The gamma and alpha index of one thermal power plant's fly ash were calculated to be 3.5 and 5 times higher than that of the reference values. The gamma absorbed dose rates were found to be higher than that of the average Earth's crust. The annual effective dose of residues measured in four thermal power plants were calculated higher than that of the permitted dose rate for public, i.e. 1 mSv y(-1). PMID:21217134

  2. Modeling of NOx emissions from fluidized bed combustion of high volatile lignites

    SciTech Connect

    Afacan, O.; Gogebakan, Y.; Selcuk, N.

    2007-01-15

    A comprehensive model, previously developed and tested for prediction of behavior of continuous fluidized bed combustors is extended to incorporate NOx formation and reduction reactions and applied to the simulation of Middle East Technical University (METU) 0.3 MW Atmospheric Bubbling Fluidized Bed Combustor (ABFBC) burning lignites with high Volatile Matter/Fixed Carbon (VM/FC) ratios in their own ashes. Favorable comparisons are obtained between the predicted and measured temperatures and concentrations of gaseous species along the combustor. Results show that determination of partitioning of coal nitrogen into char-N and volatile-N, char combustion rate, and amount of volatile nitrogen released along the combustor are found to be the most important parameters that affect NO formation and reduction in bubbling fluidized bed combustors.

  3. Use of fuzzy logic in lignite inventory estimation

    SciTech Connect

    Tutmez, B.; Dag, A.

    2007-07-01

    Seam thickness is one of the most important parameters for reserve estimation of a lignite deposit. This paper addresses a case study on fuzzy estimation of lignite seam thickness from spatial coordinates. From the relationships between input (Cartesian coordinates) and output (thickness) parameters, fuzzy clustering and a fuzzy rule-based inference system were designed. Data-driven fuzzy model parameters were derived from numerical values directly. In addition, estimations of the fuzzy model were compared with kriging estimations. It was concluded that the performance ofthe fuzzy model was more satisfactory. The results indicated that the fuzzy modeling approach is very reliable for the estimation of lignite reserves.

  4. Beysehir lignite-mining study. Final report. Export trade information

    SciTech Connect

    Not Available

    1984-03-30

    Mineable lignite has been identified at three zones in the Beysehir area of Turkey; Karadiken, Avdancik, and Akcalar. The lignite from all three areas, has definite possibilities to be economically and selectively recovered by modern open pit mining techniques. It can then be converted into fuel for a steam electric power generating station by technology that has been proven in operation for over eight years. The highest Turkish government authorities have authorized the Turkish Electricity Authority (TEK) to contract for and eventually operate both the lignite mining facility and the steam electric generating plant at Beysehir in an effort to avoid heretofore experienced delays, overruns, and under-production.

  5. Development of a sintering process for recycling oil shale fly ash and municipal solid waste incineration bottom ash into glass ceramic composite.

    PubMed

    Zhang, Zhikun; Zhang, Lei; Li, Aimin

    2015-04-01

    Oil shale fly ash and municipal solid waste incineration bottom ash are industrial and municipal by-products that require further treatment before disposal to avoid polluting the environment. In the study, they were mixed and vitrified into the slag by the melt-quench process. The obtained vitrified slag was then mixed with various percentages of oil shale fly ash and converted into glass ceramic composites by the subsequent sintering process. Differential thermal analysis was used to study the thermal characteristics and determine the sintering temperatures. X-ray diffraction analysis was used to analyze the crystalline phase compositions. Sintering shrinkage, weight loss on ignition, density and compressive strength were tested to determine the optimum preparation condition and study the co-sintering mechanism of vitrified amorphous slag and oil shale fly ash. The results showed the product performances increased with the increase of sintering temperatures and the proportion of vitrified slag to oil shale fly ash. Glass ceramic composite (vitrified slag content of 80%, oil shale fly ash content of 20%, sintering temperature of 1000 °C and sintering time of 2h) showed the properties of density of 1.92 ± 0.05 g/cm(3), weight loss on ignition of 6.14 ± 0.18%, sintering shrinkage of 22.06 ± 0.6% and compressive strength of 67 ± 14 MPa. The results indicated that it was a comparable waste-based material compared to previous researches. In particular, the energy consumption in the production process was reduced compared to conventional vitrification and sintering method. Chemical resistance and heavy metals leaching results of glass ceramic composites further confirmed the possibility of its engineering applications. PMID:25649918

  6. Utilization of lignite power generation residues for the production of lightweight aggregates.

    PubMed

    Anagnostopoulos, Iason M; Stivanakis, Victor E

    2009-04-15

    A novel process is proposed for the utilization of lignite combustion solid residues in the production of inflammable lightweight aggregates (LWA). The process consists of two stages, pelletization and sintering, and carbon contained in BA was used as the process fuel. The main residues bottom ash (BA) and fly ash (FA) from Megalopolis power plant were characterized, mixed in different proportions and treated through pelletization and sintering process. Sintering benefits from combustion of BA carbon content and the product is a hardened porous cake. The energy required for achievement of high temperatures, in the range of 1250 degrees C, was offered by carbon combustion and CO(2) evolution is responsible for porous structure formation. Selected physical properties of sintered material relevant to use as lightweight aggregates were determined, including bulk density, porosity and water absorption. Bulk density varies from 0.83 to 0.91 g/cm(3), porosity varies from 60% to 64% and water absorption varies from 66% to 80%. LWA formed is used for the production of lightweight aggregate concrete (LWAC). Thermal conductivity coefficient varies from 0.25 to 0.37 W/mK (lower than maximum limit 0.43 W/mK) and compressive strength varies from 19 to 23 MPa (higher than minimum limit 17 MPa). The results indicate that sintering of lignite combustion residues is an efficient method of utilization of carbon containing BA and production of LWA for structural and insulating purposes. Carbon content of BA is a key factor in LWA production. Finally, this research work comprises the first proposed application for utilization of BA in Greece. PMID:18804911

  7. 50. Taken from highline; "B" furnace slag pots, pipe is ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    50. Taken from high-line; "B" furnace slag pots, pipe is main blast furnace gas line from "C" furnace dust catcher; levy, slag hauler, removing slag. Looking east - Rouge Steel Company, 3001 Miller Road, Dearborn, MI

  8. Constant voltage electro-slag remelting control

    DOEpatents

    Schlienger, Max E.

    1996-01-01

    A system for controlling electrode gap in an electro-slag remelt furnace has a constant regulated voltage and an eletrode which is fed into the slag pool at a constant rate. The impedance of the circuit through the slag pool is directly proportional to the gap distance. Because of the constant voltage, the system current changes are inversely proportional to changes in gap. This negative feedback causes the gap to remain stable.

  9. Constant voltage electro-slag remelting control

    DOEpatents

    Schlienger, M.E.

    1996-10-22

    A system for controlling electrode gap in an electro-slag remelt furnace has a constant regulated voltage and an electrode which is fed into the slag pool at a constant rate. The impedance of the circuit through the slag pool is directly proportional to the gap distance. Because of the constant voltage, the system current changes are inversely proportional to changes in gap. This negative feedback causes the gap to remain stable. 1 fig.

  10. Development of a sintering process for recycling oil shale fly ash and municipal solid waste incineration bottom ash into glass ceramic composite

    SciTech Connect

    Zhang, Zhikun; Zhang, Lei; Li, Aimin

    2015-04-15

    Highlights: • Glass ceramic composite is prepared from oil shale fly ash and MSWI bottom ash. • A novel method for the production of glass ceramic composite is presented. • It provides simple route and lower energy consumption in terms of recycling waste. • The vitrified slag can promote the sintering densification process of glass ceramic. • The performances of products decrease with the increase of oil shale fly ash content. - Abstract: Oil shale fly ash and municipal solid waste incineration bottom ash are industrial and municipal by-products that require further treatment before disposal to avoid polluting the environment. In the study, they were mixed and vitrified into the slag by the melt-quench process. The obtained vitrified slag was then mixed with various percentages of oil shale fly ash and converted into glass ceramic composites by the subsequent sintering process. Differential thermal analysis was used to study the thermal characteristics and determine the sintering temperatures. X-ray diffraction analysis was used to analyze the crystalline phase compositions. Sintering shrinkage, weight loss on ignition, density and compressive strength were tested to determine the optimum preparation condition and study the co-sintering mechanism of vitrified amorphous slag and oil shale fly ash. The results showed the product performances increased with the increase of sintering temperatures and the proportion of vitrified slag to oil shale fly ash. Glass ceramic composite (vitrified slag content of 80%, oil shale fly ash content of 20%, sintering temperature of 1000 °C and sintering time of 2 h) showed the properties of density of 1.92 ± 0.05 g/cm{sup 3}, weight loss on ignition of 6.14 ± 0.18%, sintering shrinkage of 22.06 ± 0.6% and compressive strength of 67 ± 14 MPa. The results indicated that it was a comparable waste-based material compared to previous researches. In particular, the energy consumption in the production process was reduced

  11. Determination and calculation of combustion heats of 20 lignite samples

    SciTech Connect

    Demirbas, A.; Dincer, K.; Topaloglu, N.

    2008-07-01

    In this study, the proximate analyses, such as volatile matter (VM), fixed carbon (FC), and higher heating value (HHV), were determined for 20 lignite samples from different areas of Turkey. The lignite samples have been tested with particle size of 0-0.05 mm. Combustion heats (higher heating values, HHVs) of 20 lignite samples obtained from different Turkish sources were determined experimentally and calculated from both ultimate and proximate analyses. The HHVs (MJ/kg) of the lignite samples as a function of fixed carbon (FC, wt%) or volatile materials (VM, %) was calculated from the following equations: HHV = 0.2997FC + 11.1170 (1) HHV = -0.3225VM + 42.223 (2). The correlation coefficients for Eqs. (1) and (2) were 0.9820 and 0.9686, respectively. The combustion heats calculated from Eqs. (1) and (2) showed mean differences of +0.4% and +0.4%, respectively.

  12. Chemical mass balance source apportionment of TSP in a lignite-burning area of Western Macedonia, Greece

    NASA Astrophysics Data System (ADS)

    Samara, Constantini

    Total suspended particle mass concentrations (TSP) were determined in the Kozani-Ptolemais-Florina basin (western Macedonia, Greece), an area with intensive lignite burning for power generation. The study was conducted over a 1-year period (November 2000-November 2001) at 10 receptor sites located at variable distances from the power plants. Ambient TSP samples were analyzed for 27 major, minor and trace elements. Particulate emissions were also collected from a variety of sources including fly ash, lignite dust, automobile traffic, domestic heating, and open-air burning of agricultural biomass and refuse, and analyzed for the same chemical components. Ambient and source chemical profiles were used for source identification and apportionment of TSP by employing a chemical mass balance (CMB) receptor model. Diesel burning in vehicular traffic and in the power plants for generator start up was found to be the major contributor to ambient TSP levels at all 10 sites. Other sources with significant contributions were domestic coal burning, vegetative burning (wood combustion and agricultural burns) and refuse open-air burning. Fly ash escaping the electrostatic precipitators of the power plants was a minor contributor to ambient TSP.

  13. Effect of mechanical dispersion of lignite on its thermal decomposition

    SciTech Connect

    Yusupov, T.S.; Shumskaya, L.G.; Burdukov, A.P.

    2007-09-15

    It is studied how the high-rate mechanical grinding affects thermal decomposition of lignite extracted from the Kansk-Achinsk Coal Basin. It has been shown that dispersion of lignite in the high energy intensive vibration-centrifugal and planetary mills causes formation of structures exhibiting lower thermal stability. That results in the shift of primary decomposition phenomena into the low-temperature region and, thus, in the higher reactivity of coals.

  14. Mercury Control for Plants Firing Texas Lignite and Equipped with ESP-wet FGD

    SciTech Connect

    Katherine Dombrowski

    2009-12-31

    This report presents the results of a multi-year test program conducted as part of Cooperative Agreement DE-FC26-06NT42779, 'Mercury Control for Plants Firing Texas Lignite and Equipped with ESP-wet FGD.' The objective of this program was to determine the level of mercury removal achievable using sorbent injection for a plant firing Texas lignite fuel and equipped with an ESP and wet FGD. The project was primarily funded by the U.S. DOE National Energy Technology Laboratory. EPRI, NRG Texas, Luminant (formerly TXU), and AEP were project co-funders. URS Group was the prime contractor, and Apogee Scientific and ADA-ES were subcontractors. The host site for this program was NRG Texas Limestone Electric Generating Station (LMS) Units 1 and 2, located in Jewett, Texas. The plant fires a blend of Texas lignite and Powder River Basin (PRB) coal. Full-scale tests were conducted to evaluate the mercury removal performance of powdered sorbents injected into the flue gas upstream of the ESP (traditional configuration), upstream of the air preheater, and/or between electric fields within the ESP (Toxecon{trademark} II configuration). Phases I through III of the test program, conducted on Unit 1 in 2006-2007, consisted of three short-term parametric test phases followed by a 60-day continuous operation test. Selected mercury sorbents were injected to treat one quarter of the flue gas (e.g., approximately 225 MW equivalence) produced by Limestone Unit 1. Six sorbents and three injection configurations were evaluated and results were used to select the best combination of sorbent (Norit Americas DARCO Hg-LH at 2 lb/Macf) and injection location (upstream of the ESP) for a two-month performance evaluation. A mercury removal rate of 50-70% was targeted for the long-term test. During this continuous-injection test, mercury removal performance and variability were evaluated as the plant operated under normal conditions. Additional evaluations were made to determine any balance

  15. Utilization of lightweight materials made from coal gasification slags. Quarterly report, September 1, 1996--November 30, 1996

    SciTech Connect

    1997-04-01

    Integrated-gasification combined-cycle (IGCC) technology is an emerging technology that utilizes coal for power generation and production of chemical feedstocks. However, the process generates large amounts of solid waste, consisting of vitrified ash (slag) and some unconverted carbon. In previous projects, Praxis investigated the utilization of {open_quotes}as-generated{close_quotes} slags for a wide variety of applications in road construction, cement and concrete production, agricultural applications, and as a landfill material. From these studies, we found that it would be extremely difficult for {open_quotes}as-generated{close_quotes} slag to find large-scale acceptance in the marketplace even at no cost because the materials it could replace were abundantly available at very low cost. It was further determined that the unconverted carbon, or char, in the slag is detrimental to its utilization as sand or fine aggregate. It became apparent that a more promising approach would be to develop a variety of value-added products from slag that meet specific industry requirements. This approach was made feasible by the discovery that slag undergoes expansion and forms a lightweight material when subjected to controlled heating in a kiln at temperatures between 1400 and 1700{degrees}F. These results confirmed the potential for using expanded slag as a substitute for conventional lightweight aggregates (LWA). The major objectives of the subject project are to demonstrate the technical and economic viability of commercial production of LWA and ULWA from slag and to test the suitability of these aggregates for various applications.

  16. Slag characterization and removal using pulse detonation for coal gasification. Quarterly research report, January 1, 1996--March 31, 1996

    SciTech Connect

    Huque, Z.; Mei, D.; Biney, P.O.; Zhou, J.

    1996-03-25

    Microbeam Technologies Incorporated (MTI) is working with Prairie View to develop and demonstrate a new method to remove deposits from coal-fired utility boilers. MTI is providing background information on fuel properties, ash formation, ash deposition, and ash removal. In addition, MTI is providing deposits collected from a full scale utility boilers. Ash deposits on fireside heat exchange surfaces of power plants significantly decrease plant efficiency and are aggravated by variability in coal quality. Deposit formation is related to coal quality (chemical and physical characteristics of the inorganic material), system operating conditions, and system design. Variations in coal quality can significantly influence ash deposition on heat transfer surfaces resulting in decreased plant performance and availability. Ash accumulations on heat transfer surfaces require annual or semi-annual shutdowns for cleaning which result in cleaning costs and lost revenues from being off-line. In addition, maintaining slag flow in wet bottom boilers and cyclone-fired boilers can require co-firing of other fuels and outages to remove frozen slag resulting in decreased efficiency and availability. During this reporting period MTI performed analysis of deposits collected from full-scale utility boilers. Deposit samples were obtained from Basin Electric and from Northern States Power (NSP). The analyses were conducted using scanning electron microscopy/microprobe techniques as described in the past quarterly report. The chemical and physical properties of the deposits were determined. The results for sample collected from NSP`s Riverside plant are reported here.

  17. Greener durable concretes through geopolymerisation of blast furnace slag

    NASA Astrophysics Data System (ADS)

    Rajamane, N. P.; Nataraja, M. C.; Jeyalakshmi, R.; Nithiyanantham, S.

    2015-05-01

    The eco-friendliness of concrete is quantified by parameters such as ‘embodied energy’ (EE) and ‘embodied CO2 emission’ (ECO2e), besides duration of designed ‘service life’. It may be noted that ECO2e is also referred as carbon footprint (CF) in the literature. Geopolymer (GP) is an inorganic polymeric gel, a type of amorphous alumino-silicate product, which can be synthesised by polycondensation reactions. The concrete reported in this paper was prepared using industrial wastes in the form of blast furnace slag, fly ash as geopolymeric source materials and sodium silicate and sodium hydroxide as activators. Many mechanical properties such as compressive strength, chloride diffusion, steel corrosion, rapid chloride permeability test and rapid migration test are compared with Portland cement.

  18. Functional design of refractories for slagging gasifiers

    SciTech Connect

    Kwong, Kyei-Sing; Dogan, Cynthia P.; Bennett, James P.; Chinn, Richard E.; Dahlin, Cheryl L.

    2002-09-01

    Refractories are used in coal slagging gasifiers to protect the outer steel shell from coal slag attack and to insulate it from heat. Corrosion by the aggressive coal slags and unexpected temperature shock severely shorten the service life of these refractories. Currently, the best refractories available for the slagging coal gasifiers last from 6 to 18 months. The down time for the installation of new refractory lining reduces on-line availability of the gasifier. Researchers at the Albany Research Center (ARC) have found that structural spalling by slag penetration into the refractory is responsible for the early failure of refractories in some gasifiers. The low melting point of coal slags, the low thermal gradient in the refractory, and the improper design of refractory microstructure contribute to promote slag penetration. Work at ARC has demonstrated that refractories with an improved functional design are more resistant to slag penetration. Cooperation with commercial refractory companies and gasifier designers/operators is underway to produce and test improved refractories.

  19. Neural network predictions of slagging and fouling in pulverized coal-fired utility boilers

    SciTech Connect

    Wildman, D.; Smouse, S.; Chi, R.

    1996-12-31

    Feed-forward back-propagation neural networks were trained to relate the occurrence and characteristics of troublesome slagging and fouling deposits in utility boilers to coal properties, boiler design features, and boiler operating conditions. The data used in this effort were from a survey of utility boilers conducted by Battelle Columbus Laboratories in an Electric Power Research Institute project. Two networks were developed in this study, one for slagging and one for fouling, to predict ash deposition in various types of boilers (wall-, opposed wall-, tangentially, and cyclone-fired) that fire bituminous and sub-bituminous coals. Both networks predicted the frequency of deposition problems, physical nature (or state) of the deposit, and the thickness of the deposit. Since deposit characteristics vary with boiler location and operating conditions, the worst documented cases of ash deposition were used to train the neural networks. Comparison of actual and predicted deposition showed very good agreement in general. The relative importance of some of the input variables on the predicted deposit characteristics were assessed in a sensitivity analysis. Also, the slagging and fouling characteristics of a blend of two coals with significant different deposition characteristics were predicted to demonstrate a practical application of developed neural networks.

  20. Slag-Refractory Interaction in Coal Gasifiers

    SciTech Connect

    Sundaram, S. K.; Johnson, Kenneth I.; Williford, Ralph E.; Pilli, Siva Prasad; Matyas, Josef; Fluegel, Alexander; Cooley, Scott K.; Crum, Jarrod V.; Edmondson, Autumn B.

    2007-10-13

    Pacific Northwest National Laboratory (PNNL) has taken an integrated approach to address major technical issues in conversion of coal into clean-burning liquid fuel. The approach includes: 1) modeling of gasifier and slag flow, 2) experimental characterization of slag viscoelastic behavior as a function of temperature for representative slags and refractory-slag interactions, and 3) interplay of the modeling and experimental measurements to identify critical conditions beyond which refractory corrosion tends to increase sharply. Basic heat and mass balances were considered in the gasifier and flow models. Two new refractory spalling models were developed. An experimental design that encompassed the broad range of slag chemistries that were of interest to coal gasification was developed and implemented. Selected gasifier refractories were tested in a simulated gasifier environment in our laboratory to identify refractory degradation mechanisms. Preliminary results of the effort are summarized.

  1. Get smart about removing slag

    SciTech Connect

    Wicker, K.

    2005-10-01

    More often than not, sootblowing is literally a shot in the dark. Clyde Bergemann's solution to this problem: control sootblowing operations intelligently, based on the outputs of real-time weight and heat-flux sensors and the calculations of a computer model. The company's intelligent sootblowing system contains many pieces - SmartCannons to clean the furnace by water jets; SmartSensors to detect heat flux, SmartGuages to detect slag buildup, SmartLances aimed at the superheater and reheater, SmartModel to determine when and where cleaning is needed, and SmartControls to direct operations. 3 figs.

  2. CO2 sequestration by carbonation of steelmaking slags in an autoclave reactor.

    PubMed

    Chang, E-E; Pan, Shu-Yuan; Chen, Yi-Hung; Chu, Hsiao-Wen; Wang, Chu-Fang; Chiang, Pen-Chi

    2011-11-15

    Carbon dioxide (CO(2)) sequestration experiments using the accelerated carbonation of three types of steelmaking slags, i.e., ultra-fine (UF) slag, fly-ash (FA) slag, and blended hydraulic slag cement (BHC), were performed in an autoclave reactor. The effects of reaction time, liquid-to-solid ratio (L/S), temperature, CO(2) pressure, and initial pH on CO(2) sequestration were evaluated. Two different CO(2) pressures were chosen: the normal condition (700 psig) and the supercritical condition (1300 psig). The carbonation conversion was determined quantitatively by using thermo-gravimetric analysis (TGA). The major factors that affected the conversion were reaction time (5 min to 12h) and temperature (40-160°C). The BHC was found to have the highest carbonation conversion of approximately 68%, corresponding to a capacity of 0.283 kg CO(2)/kg BHC, in 12h at 700 psig and 160°C. In addition, the carbonation products were confirmed to be mainly in CaCO(3), which was determined by using scanning electron microscopy (SEM) and X-ray powder diffraction (XRD) to analyze samples before and after carbonation. Furthermore, reaction kinetics were expressed with a surface coverage model, and the carbon footprint of the developed technology in this investigation was calculated by a life cycle assessment (LCA). PMID:21889848

  3. Variation and correlation of content and leachability of hazardous metals in MSW molten slag.

    PubMed

    Sekito, T; Onoue, K; Dote, Y; Sakanakura, H; Nakamura, K

    2015-01-01

    To increase the amount of accessible municipal solid waste molten slag (MSWS) for its use in aggregates such as sand, MSWS must be deemed environmentally safe. Municipal solid waste (MSW) is a heterogeneous waste source used in MSWS and varies in chemical composition. Due to its nature, there is great concern about hazardous metal contamination among users of MSWS. In this study, MSWS samples were obtained weekly for 1 year from a typical incineration ash melting facility for municipal solid waste in Japan. Variation in heavy metal contents and the leachability of MSWS were investigated using two content analysis methods and two leaching tests, respectively. There is a weak correlation between metal content and concentration, and the leachability of metals in slag could not be reduced by decreasing its metal content. No measured values of hazardous metal concentration and metal content exceed the regulation levels stipulated in Japanese Industrial Standards A5031 and A5032, respectively, thereby demonstrating that the slag can be safely utilized as road and concrete aggregates. However, metal concentrations varied widely and differed by greater than 1 order of magnitude and Pb concentrations of several MSWS samples approach the regulation level. Therefore, frequent monitoring of lead leachability of MSWS and storing MSWS for several weeks to obtain a high quality that is more homogeneous in chemical composition are demanded. This study provides fundamental information for controlling the quality of MSWS and the contributing factors for achieving a safe slag recycling system. PMID:25504189

  4. Characteristics of element distributions in an MSW ash melting treatment system.

    PubMed

    Sekito, T; Dote, Y; Onoue, K; Sakanakura, H; Nakamura, K

    2014-09-01

    Thermal treatment of municipal solid waste (MSW) has become a common practice in waste volume reduction and resource recovery. For the utilization of molten slag for construction materials and metal recovery, it is important to understand the behavior of heavy metals in the melting process. In this study, the correlation between the contents of elements in feed materials and MSW molten slag and their distributions in the ash melting process, including metal residues, are investigated. The hazardous metal contents in the molten slag were significantly related to the contents of metals in the feed materials. Therefore, the separation of products containing these metals in waste materials could be an effective means of producing environmentally safe molten slag with a low hazardous metals content. The distribution ratios of elements in the ash melting process were also determined. The elements Zn and Pb were found to have a distribution ratio of over 60% in fly ash from the melting furnace and the contents of these metals were also high; therefore, Zn and Pb could be potential target metals for recycling from fly ash from the melting furnace. Meanwhile, Cu, Ni, Mo, Sn, and Sb were found to have distribution ratios of over 60% in the metal residue. Therefore, metal residue could be a good resource for these metals, as the contents of Cu, Ni, Mo, Sn, and Sb in metal residue are higher than those in other output materials. PMID:24863626

  5. Effect of carbonaceous particles on slag foaming

    NASA Astrophysics Data System (ADS)

    Zhang, Y.; Fruehan, R. J.

    1995-08-01

    Use of carbonaceous particles such as coke or coal char in controlling slag foaming is of great practical significance for bath-smelting and other steelmaking processes. The foamability of the liquid slag in terms of the foam index has been determined with the presence of different amounts of coke and coal char particles. Different sized and shaped particles were used in the experiments. It was found that the foam index decreased significantly as the ratio of the total cross-sectional area of the particles to the liquid slag surface area increased. When the foam was generated by argon gas injection through an alumina nozzle (i.d. = 1.5 mm), a liquid slag, CaO-SiO2-CaF2-(Al2O3), depending on the alumina content, could have an initial foam index of about 2 to 4 seconds at 1500 °C without any carbonaceous particles. When the slag surface was covered only 15 ~20 pct with either coke or coal char particles, the foam was totally suppressed regardless of the initial foam index. In order to understand the mechanism of the antifoam effect of the carbonaceous particles, interactions of a coke sphere, an iron ore pellet, an alumina tube, and a coal char particle with the liquid slag foam were examined by X-ray observation. It was concluded that the antifoam effect of coke or coal char particles is primarily contributed by the nonwetting nature of the carbonaceous materials with the liquid slag. Possible mechanisms of carbonaceous particles rupturing a slag film could be (1) the rapid thinning of the liquid slag film driven by a difference between the instantaneous contact angle and the equilibrium contact angle or (2) the “dewetting” of the liquid slag from the interface when the film is “bridged” by the particle.

  6. Microbial screening test for lignite degradation. Quarterly progress report No. 1, January-March 1985

    SciTech Connect

    Yen, T.F.

    1985-01-01

    Potassium permanganate and sodium hypochlorite oxidation of lignitic coal were performed. Ion chromatography of low molecular weight carboxylic acids - oxalic acid, formic acid, and acetic acid - produced by potassium permanganate and sodium hypochlorite oxidation was executed. Oxalic acid was found to be the most predominant low molecular weight species. It was estimated that about 10% of the carbon present in the chemical structure of lignite was converted to oxalic acid by sodium hypochlorite oxidation. Ion chromatography analysis showed that about 43% of the lignite carbon was converted to carbon dioxide in all experiments. Biological degradation of lignite by P. versicolor, a white-rot fungus, on lignite/agar and lignite slurry was attempted. Apparently, P. versicolor is capable of growing on lignite slurry. Acclimation of P. versicolor to lignite was proceeded. Biochemical reaction test for laccase production of P. versicolor was performed and found to be positive. 15 refs., 5 figs., 6 tabs.

  7. Uses found for gasification slag

    SciTech Connect

    Not Available

    1986-12-01

    A study carried out for the Electric Power Research Institute by Praxis Engineers, Inc. has examined possible uses for the gasifier slag produced during coal gasification. After describing some of the problems foreseen to market development, seven categories of uses are listed and briefly discussed. The possible uses for slag identified are: (1) Agriculture (soil conditioner, lime substitute, low analysis fertilizer, carrier for insecticides); (2) Industrial material (abrasive grit, catalyst and adsorbent, roofing granules, industrial filler, mineral wool production, filter media); (3) Cement and Concrete (concrete aggregate, mortar/grouting material, pozzolanic admixture, raw materials for Portland cement production, masonary unit production); (4) Road Construction and Maintenance (de-icing grit, fine aggregate for bituminous pavement, base aggregate, sub-base aggregate, seal-cost aggregate); (5) Synthetic Aggregate (lightweight construction aggregate, landscaping material, sand substitute); (6) Land Fill and Soil Stabilization (soil conditioner for improving stability, structural fill, embankment material); (7) Resource Recovery (source of carbon, magnetite, iron, aluminium, and other metals). 2 tables.

  8. An analysis of the causes of failure in high chrome oxide refractory materials from slagging gasifiers

    SciTech Connect

    Bennett, James P.; Kwong, Kyei-Sing; Powell, Cynthia A.; Thomas, Hugh; Krabbe, Rick

    2006-01-01

    High Cr2O3 refractory materials are used to line the hot face of slagging gasifiers. Gasifiers are reaction chambers that convert water, oxygen, and a carbon feedstock into CO, H2, and methane at temperatures as high as 1575DGC and pressures up to 1000 psi. Ash in the carbon feedstock liquefies, erodes and corrodes the gasifier's refractory liner, contributing to liner failure within a few months to two years. The failure of a refractory liner decreases a gasifier's on-line availability and causes costly system downtime and repairs. Many factors contribute to refractory lining failure, including slag penetration and corrosion, thermal cycling, gasifier environment, and mechanical loads. The results of refractory post-mortem failure analysis and how observations relate to gasifier service life will be discussed.

  9. Analysis of the causes of failure in high chrome oxide refractory materials from slagging gasifiers

    SciTech Connect

    Bennett, J.P.; Kwong, K.-S.; Powell, C.A.; Thomas, H.; Krabbe, R.A.

    2006-03-01

    High Cr2O3 refractory materials are used to line the hot face of slagging gasifiers. Gasifiers are reaction chambers that convert water, oxygen, and a carbon feedstock into CO, H2, and methane at temperatures as high as 1575oC and pressures up to 1000 psi. Ash in the carbon feedstock liquefies, erodes and corrodes the gasifier’s refractory liner, contributing to liner failure within a few months to two years. The failure of a refractory liner decreases a gasifier’s on-line availability and causes costly system downtime and repairs. Many factors contribute to refractory lining failure, including slag penetration and corrosion, thermal cycling, gasifier environment, and mechanical loads. The results of refractory post-mortem failure analysis and how observations relate to gasifier service life will be discussed.

  10. Fundamental studies of the mechanisms of slag deposit formation: Studies on initiation, growth and sintering in the formation of utility boiler deposits: Topical technical report

    SciTech Connect

    Tangsathitkulchai, M.; Austin, L.G.

    1986-03-01

    Three laboratory-scale devices were utilized to investigate the mechanisms of the initiation, growth and sintering process involved in the formation of boiler deposits. Sticking apparatus investigations were conducted to study deposit initiation by comparing the adhesion behavior of the ash drops on four types of steel-based heat exchanger materials under the conditions found in a utility boiler and an entrained slagging gasifier. In addition, the adhesion behavior of the ash drops on a reduced steel surface were investigated. All the ash drops studied in this investigation were produced from bituminous coals.

  11. Detoxifying PCDD/Fs and heavy metals in fly ash from medical waste incinerators with a DC double are plasma torch.

    PubMed

    Pan, Xinchao; Yan, Jianhua; Xie, Zhengmiao

    2013-07-01

    Medical waste incinerator (MWI) fly ash is regarded as a highly toxic waste because it contains high concentrations of heavy metals and dioxins, including polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs). Therefore fly ash from MWI must be appropriately treated before being discharged into the environment. A melting process based on a direct current thermal plasma torch has been developed to convert MWI fly ash into harmless slag. The leaching characteristics of heavy metals in fly ash and vitrified slag were investigated using the toxicity characteristic leaching procedure, while the content of PCDD/Fs in the fly ashes and slags was measured using method 1613 of the US EPA. The experimental results show that the decomposition rate of PCDD/Fs is over 99% in toxic equivalent quantity value and the leaching of heavy metals in the slag significantly decreases after the plasma melting process. The produced slag has a compact and homogeneous microstructure with density of up to 2.8 g/cm3. PMID:24218848

  12. New laser technology helps reduce coal-slagging headaches

    SciTech Connect

    Neville, A.

    2009-02-15

    Laser-induced breakdown spectroscopy (LIBS) is starting to light the way for power plant operators who want to reduce coal ash deposition in their boilers. The method was developed by Lehigh University's Energy Research Centre and the Energy Research Co. The LIBS system analyzes the chemical properties of coal using a pulsating laser with two frequencies, one infrared and one visible light. The laser vaporizes a sample, resulting in a distinct elemental signature. From these data, a newly developed software package containing artificial neural network (ANN) models estimates ash fusion temperature and predicts coal slagging potential. LIBS is the size of a table top, safe to use and provides instantaneous data without interrupting the process. The performance of the LIBS system was verified in lab experiments and then the system was set up at Dominion's Brayton Point Power Station, a 1,150-MW coal-fired power plant in Somerset, MA. The project demonstrated the merit of the LIBS system that produces coal elemental analysis and estimated fusion temperatures. Further development is needed to equip a LIBS system with an automatic online coal-sampling attachment and to achieve higher accuracy and repeatability. The researchers have been awarded a second DOE grant to fund development of a commercial prototype of the LIBS system. 2 figs., 2 photos.

  13. Ash from the combustion of Ekibastuzsk coals - a raw material for obtaining glasses and aluminium

    SciTech Connect

    Suleimenov, S.T.

    1984-01-01

    The ash content of the Ekibastuzsk coal deposit is up to 45%. The ash contains 26-30% Al2O3, 60-65% SiO2 and at least 4-5% coke. It was mixed with 20-30% slag from the phosphorus industry and 4-5% sodium sulphate for the making of glass ceramic tiles. The good acid resistance of these tiles makes them suitable for lining the equipment in which Al is extracted from the same ash for producing aluminium sulphate.

  14. Thermal decomposition behaviors of lignite by pyrolysis-FTIR

    SciTech Connect

    Feng, J.; Li, W.Y.; Xie, K.C.

    2006-01-21

    An in situ pyrolysis reactor combined with the Fourier transformation infrared spectrometer (PFTIR) technique is employed to study the coal structure and its thermal decomposition behaviors. The interface of pyroprobe with FTIR was designed delicately to ensure the path of the laser beam in FTIR was just 3 {mu}m above the coal sample, so any detection information of products from coal pyrolysis would be acquired previous to the secondary reaction. The PFTIR technique can be adopted to determine the activation energy of coal pyrolysis. Lignite coal has been used to evaluate this new method. The thermal decomposition behaviors of functional groups from lignite pyrolysis coincide with the first-order reaction.

  15. Co-gasification of solid waste and lignite - a case study for Western Macedonia.

    PubMed

    Koukouzas, N; Katsiadakis, A; Karlopoulos, E; Kakaras, E

    2008-01-01

    Co-gasification of solid waste and coal is a very attractive and efficient way of generating power, but also an alternative way, apart from conventional technologies such as incineration and landfill, of treating waste materials. The technology of co-gasification can result in very clean power plants using a wide range of solid fuels but there are considerable economic and environmental challenges. The aim of this study is to present the available existing co-gasification techniques and projects for coal and solid wastes and to investigate the techno-economic feasibility, concerning the installation and operation of a 30MW(e) co-gasification power plant based on integrated gasification combined cycle (IGCC) technology, using lignite and refuse derived fuel (RDF), in the region of Western Macedonia prefecture (WMP), Greece. The gasification block was based on the British Gas-Lurgi (BGL) gasifier, while the gas clean-up block was based on cold gas purification. The competitive advantages of co-gasification systems can be defined both by the fuel feedstock and production flexibility but also by their environmentally sound operation. It also offers the benefit of commercial application of the process by-products, gasification slag and elemental sulphur. Co-gasification of coal and waste can be performed through parallel or direct gasification. Direct gasification constitutes a viable choice for installations with capacities of more than 350MW(e). Parallel gasification, without extensive treatment of produced gas, is recommended for gasifiers of small to medium size installed in regions where coal-fired power plants operate. The preliminary cost estimation indicated that the establishment of an IGCC RDF/lignite plant in the region of WMP is not profitable, due to high specific capital investment and in spite of the lower fuel supply cost. The technology of co-gasification is not mature enough and therefore high capital requirements are needed in order to set up a direct

  16. Molten Slag Would Boost Coal Conversion

    NASA Technical Reports Server (NTRS)

    Ferrall, J. F.

    1984-01-01

    Reactor increases residence time of uncovered char. Near-100percent carbon conversion achievable in reactor incorporating moltenslag bath. Slag maintains unconverted carbon impinging on surface at high temperatures for longer period of time, enhancing conversion.

  17. MgO Solubility in Steelmaking Slags

    NASA Astrophysics Data System (ADS)

    Tayeb, Mohammed A.; Assis, Andre N.; Sridhar, Seetharaman; Fruehan, Richard J.

    2015-04-01

    A predominantly liquid and MgO-saturated slag is preferred in EAF and BOF steelmaking. Fully liquid slag provides a better environment for faster mass transfer due to lower bulk viscosities and larger liquid slag volume and these help dephosphorization and desulfurization. Also, an MgO-saturated slag would be preferable in order to increase the lifetime of furnace refractory lining by reducing the extent of dissolution. This article will demonstrate the factors that would influence MgO saturation, which includes FeO, CaO, P2O5, and Al2O3 contents and temperature. In addition, this paper comments on the applicability and accuracy of FactSage prediction, which are compared to laboratory experiments. The results indicate that FactSage may underestimate MgO solubility by up to 2.5 wt pct at higher basicities while there is reasonable agreement with current measurements at lower basicities.

  18. Improving thermocouple service life in slagging gasifiers

    SciTech Connect

    Bennett, James P.; Kwong, Kyei-Sing; Powell, Cynthia A.; Thomas, Hugh; Krabbe, Rick

    2005-01-01

    The measurement of temperature within slagging gasifiers for long periods of time is difficult/impossible because of sensor failure or blockage of inputs used to monitor gasifier temperature. One of the most common means of temperature measurement in a gasifier is physically, through the use of thermocouples in a gasifier sidewall. These units can fail during startup, standby, or during the first 40-90 days of gasifier service. Failure can be caused by a number of issues; including thermocouple design, construction, placement in the gasifier, gasifier operation, and molten slag attack of the materials used in a thermocouple assembly. Lack of temperature control in a gasifier can lead to improper preheating, slag buildup on gasifier sidewalls, slag attack of gasifier refractories used to line a gasifier, or changes in desired gas output from a gasifier. A general outline of thermocouple failure issues and attempts by the Albany Research Center to improve the service life of thermocouples will be discussed.

  19. Seismic behavior of geogrid reinforced slag wall

    SciTech Connect

    Edincliler, Ayse; Baykal, Gokhan; Saygili, Altug

    2008-07-08

    Flexible retaining structures are known with their high performance under earthquake loads. In geogrid reinforced walls the performance of the fill material and the interface of the fill and geogrid controls the performance. Geosynthetic reinforced walls in seismic regions must be safe against not only static forces but also seismic forces. The objective of this study is to determine the behavior of a geogrid reinforced slag wall during earthquake by using shaking table experiments. This study is composed of three stages. In the first stage the physical properties of the material to be used were determined. In the second part, a case history involving the use of slag from steel industry in the construction of geogrid reinforced wall is presented. In the third stage, the results of shaking table tests conducted using model geogrid wall with slag are given. From the results, it is seen that slag can be used as fill material for geogrid reinforced walls subjected to earthquake loads.

  20. Semi lightweight concretes produced by volcanic slags

    SciTech Connect

    Topcu, I.B.

    1997-01-01

    The properties of the semi-lightweight concretes produced by using volcanic slags as coarse aggregate were investigated. The volcanic slags were brought from the quarry crushed and then classified according to their aggregate sizes of 0--8, 0--16, 0--31.5, 4--8, and 8--16 mm. The concrete series of five different volcanic slag sizes were produced by addition of a specific cement paste in volume fractions of 0.15, 0.30, 0.45 and 0.60. The cubic, cylindrical and prismatic specimens were made from each of the concrete series. The physical and mechanical properties of the concrete series were determined by conducting unit weight, slump, ultrasound velocity, Schmidt hardness, cylindrical and cubic compressive, bending and splitting tensile strength tests. The results indicated that the volcanic slags can be safely used in the production of semi lightweight concrete.

  1. Reaction of iron and steel slags with refractories

    SciTech Connect

    Banerjee, S.; Anderson, M.W.

    1993-04-01

    Slag corrosion and erosion has been a major wear factor for refractories wear in contact with molten iron and steel. In blast furnace ironmaking, the slag/iron interface plays a more important role than does the slag/refractory interface. On the other hand in steelmaking, the slag in the ladles and tundish predominantly affect refractory wear. This paper presents the results of a detailed microstructural evaluation of (a) slag and slag/iron interactions with A1{sub 2}O{sub 3}-SiC-C refractories for ironmaking in blast furnaces, (b) basic oxygen furnace and ladle slag interactions with alumina spinel refractories for steelmaking, and (c) slag interactions with working refractory lining for continuous casting tundishes. Results will also be presented on refractory wear/failure due to simultaneous corrosion and penetration by the slag.

  2. Characterization of a fluidized-bed combustion ash to determine potential for environmental impact. Final report

    SciTech Connect

    Hassett, D.J.; Henderson, A.K.; Pflughoeft-Hassett, D.F.; Mann, M.D.; Eylands, K.E.

    1997-10-01

    A 440-megawatt, circulating fluidized-bed combustion (CFBC), lignite-fired power plant is planned for construction in Choctaw County north of Ackerman, Mississippi. This power plant will utilize Mississippi lignite from the first lignite mine in that state. Malcolm Pirnie, Inc., is working with the power plant developer in the current planning and permitting efforts for this proposed construction project. In order to accommodate Mississippi state regulatory agencies and meet appropriate permit requirements, Malcolm Pirnie needed to provide an indication of the characteristics of the by-products anticipated to be produced at the proposed plant. Since the Mississippi lignite is from a newly tapped mine and the CFBC technology is relatively new, Malcolm Pirnie contacted with the Energy and Environmental Research Center (EERC) to develop and perform a test plan for the production and characterization of ash similar to ash that will be eventually produced at the proposed power plant. The work performed at the EERC included two primary phases: production of by-products in a bench-scale CFBC unit using lignite provided by Malcolm Pirnie with test conditions delineated by Malcolm Pirnie to represent expected operating conditions for the full-scale plant; and an extensive characterization of the by-products produced, focusing on Mississippi regulatory requirements for leachability, with the understanding that return of the by-product to the mine site was an anticipated by-product management plan. The overall focus of this project was the environmental assessment of the by-product expected to be produced at the proposed power plant. Emphasis was placed on the leachability of potentially problematic trace elements in the by-products. The leaching research documented in this report was performed to determine trends of leachability of trace elements under leaching conditions appropriate for evaluating land disposal in monofills, such as returning the by-products to the mine

  3. Triple-activated blast furnace slag

    SciTech Connect

    Clarke, W.J.

    1995-12-31

    The current shortage of portland cement in the world will require the use of Ground Granulated Blast Furnace Slag (GGBFS) to fill demands in many industrialized countries. Therefore, an extensive series of triple-activated slag experiments have been undertaken to optimize an economical combination of mechanical properties for alkali-activated slags. Na{sub 2}OSiO{sub 2} (N Grade), Ca(OH){sub 2}, H{sub 2}O and Na{sub 2}CO{sub 3} have been added as activators in 5 to 10, 0 to 5 and 0 to 5 weight percentages of water and slag in a mix with a water:cement ratio of 1:1. Silica Fume and Sika 10 superplasticizer have been added as 1 and 10 weight percent of slag. Set times, initial hardening times and compressive strengths at percentages of the mix to identify more refined formulations. Finally, the resulting aggregate to develop a triple-activated slag formulation with the ultimate objective of contributing toward satisfying the world shortage of high performance concrete.

  4. Preparation of steel slag porous sound-absorbing material using coal powder as pore former.

    PubMed

    Sun, Peng; Guo, Zhancheng

    2015-10-01

    The aim of the study was to prepare a porous sound-absorbing material using steel slag and fly ash as the main raw material, with coal powder and sodium silicate used as a pore former and binder respectively. The influence of the experimental conditions such as the ratio of fly ash, sintering temperature, sintering time, and porosity regulation on the performance of the porous sound-absorbing material was investigated. The results showed that the specimens prepared by this method had high sound absorption performance and good mechanical properties, and the noise reduction coefficient and compressive strength could reach 0.50 and 6.5MPa, respectively. The compressive strength increased when the dosage of fly ash and sintering temperature were raised. The noise reduction coefficient decreased with increasing ratio of fly ash and reducing pore former, and first increased and then decreased with the increase of sintering temperature and time. The optimum preparation conditions for the porous sound-absorbing material were a proportion of fly ash of 50% (wt.%), percentage of coal powder of 30% (wt.%), sintering temperature of 1130°C, and sintering time of 6.0hr, which were determined by analyzing the properties of the sound-absorbing material. PMID:26456608

  5. GAMMA RADIATION TREATMENT OF WATERS FROM LIGNITE MINES

    EPA Science Inventory

    Discussed in this report are results of laboratory investigations carried out with the application of gamma radiation for the purification of waters drained from surface lignite mines. These waters are polluted to a considerable extent with suspended matter of various sizes, a la...

  6. PURIFICATION OF WATERS DISCHARGED FROM POLISH LIGNITE MINES

    EPA Science Inventory

    The exploitation of lignite deposits is linked with the necessity of lowering the groundwater table and dewatering the mine of precipitation. A large percentage of the discharge waters requires purification prior to delivery of receiving streams. The chief pollutants of these wat...

  7. WASHABILITY CHARACTERISTICS OF ARKANSAS AND TEXAS LIGNITES: REPORT OF INVESTIGATIONS

    EPA Science Inventory

    The report describes the washability characteristics of 11 channel samples of lignite: 4 from Arkansas and 7 from Texas. The two samples collected from Dallas County, Arkansas, could be upgraded to meet the current EPA New Source Performance Standard (NSPS) of 1.2 lb SO2/million ...

  8. 30 CFR 75.380 - Escapeways; bituminous and lignite mines.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Escapeways; bituminous and lignite mines. 75.380 Section 75.380 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE SAFETY AND HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Ventilation §...

  9. 30 CFR 75.380 - Escapeways; bituminous and lignite mines.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Escapeways; bituminous and lignite mines. 75.380 Section 75.380 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE SAFETY AND HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Ventilation §...

  10. 30 CFR 75.380 - Escapeways; bituminous and lignite mines.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Escapeways; bituminous and lignite mines. 75.380 Section 75.380 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE SAFETY AND HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Ventilation §...

  11. 30 CFR 75.380 - Escapeways; bituminous and lignite mines.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Escapeways; bituminous and lignite mines. 75.380 Section 75.380 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE SAFETY AND HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Ventilation §...

  12. 30 CFR 75.380 - Escapeways; bituminous and lignite mines.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Escapeways; bituminous and lignite mines. 75.380 Section 75.380 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE SAFETY AND HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Ventilation §...

  13. Investigation of pyrite as a contributor to slagging in Eastern bituminous coals. Quarterly progress report, October 1, 1981-February 28, 1982

    SciTech Connect

    Not Available

    1982-03-01

    Slagging by bituminous eastern US coals in industrial furnaces results primarily from pyritic iron in the coal ash. Since it has been learned that coals of similar pyritic levels fired in furnaces of similar design do not always produce the same slagging conditions, and since segregation of pyrites from other minerals does occur when slagging is encountered, slagging must be attributed to the size and orientation of the pyrites in the coal, in addition to their concentration level. A program is underway to examine slags from coals with varying concentration levels, size distribution, and orientation of pyrite with other mineral matter, when the coals are fired in a laboratory furnace under controlled conditions simulating an industrial furnace. During Task 1 Foster Wheeler will select eight candidate coals with variations in pyrite size and distribution according to the specifications of the Research Plan. The selection will be made after reviewing the specification with such agencies as the DOE Fuel Preparation Laboratory at Bruceton, Pennsylvania; the Pennsylvania State College of Mineralogy and Coal Combustion Laboratory; the Coal Research Department of the University of Kentucky; the Indiana State Geological Survey; and the Illinois Geological Survey. Foster Wheeler will locate the source of each coal, negotiate the coal purchase, and arrange for shipment of the required amount of each coal selected. The coals will be selected to provide a suitable matrix of pyrite size distribution and concentration, permitting identification of the source of pyrite responsible for slagging.

  14. A Novel Kinematic Model for Molten Slag Fiberization: Prediction of Slag Fiber Properties

    NASA Astrophysics Data System (ADS)

    Zhao, Dawei; Zhang, Zuotai; Liu, Lili; Wang, Xidong

    2015-04-01

    The current study developed a novel kinematic model describing the molten slag fiberization process with a purpose of understanding the slag wool preparation. A reasonable predictive model to describe the diameter and length of slag fiber in commercial fiber making process is necessary because the length-to-diameter ratio has a huge impact on the thermal insulation performance, which will contribute to energy conservation. The current model was established based on melt droplet kinematics under relevant hypotheses. Through this model, changes in fiber dimensions with slag viscosity and rotational speed of spinning wheel have been systematically investigated to determine the optimized technological parameters. To verify the model, experiments were carried out and the results were in good agreement with the predicted values. Thus, the current model can serve as a useful guide for the industrial production of slag wool.

  15. Summary of the engineering assessment of inactive uranium-mill tailings, Bowman Site, Bowman, North Dakota. [Burning of uranium-bearing lignite

    SciTech Connect

    1981-11-01

    Ford, Bacon and Davis Utah Inc. has performed an engineering assessment of the problems resulting from the existence of radioactive residues from the burning of uranium-bearing lignite at Bowman, North Dakota. This engineering assessment has included the preparation of topographic maps, the performance of core drillings and radiometric measurements sufficient to determine areas and volumes of ash residues and radiation exposures of individuals and nearby populations, the investigations of site hydrology and meteorology, and the evaluation and costing of alternative corrective actions. Radon gas released from the 97,000 tons of ash and contaminated materials at the Bowman site constitutes a significant environmental impact, although windblown ash and external gamma radiation also are factors. The four alternative actions presented in this engineering assessment range from millsite decontamination with the addition of 3 m of stabilization cover material (Option I), to removal of the contaminated materials to remote disposal sites and decontamination of the ashing site (Options II through IV). Cost estimates for the four options range from about $1,740,000 for stabilization in-place, to about $3,060,000 for disposal at a distance of about 4 mi. Reprocessing the ash for uranium recovery is not feasible because of the extremely small amount of material available at the site and because of its low U/sub 3/O/sub 8/ content.

  16. Viscosity Determination of Molten Ash from Low-Grade US Coals

    DOE PAGESBeta

    Zhu, Jingxi; Nakano, Jinichiro; Kaneko, Tetsuya Kenneth; Mu, Haoyuan; Bennett, James P.; Kwong, Kyei-Sing; Rozelle, Peter; Sridhar, Seetharaman

    2012-10-01

    In entrained slagging gasifiers, the fluidity of the molten ash is a critical factor for process control since it affects slag formation, the capture of inorganic constituents, refractory wear, and slag drainage along the gasification chamber walls. The use of western coal, or mixtures of eastern and western coals as gasifier feedstock, is likely to occur as western coals become available and technological issues that hinder their use are being resolved. In the present work, the viscosity of synthetic slags with ash chemistries simulating the western U.S. coals, was experimentally measured at a Po2 = 10- 8 atm in themore » temperature range of 1773–1573 K (1500–1300 °C) using a rotating-bob viscometer. Alumina spindles and containment crucibles of both alumina and zirconia were used. Crystallization studies of this slag using a confocal scanning laser microscope found that a (Mg,Fe)Al2O4-based spinel precipitated at temperatures below 1723 K (1450 °C), and this agreed with FactSage equilibrium phase prediction. The same spinels were observed in the post-viscometry experiment slags when ZrO2 crucibles were used and assumed to be in equilibrium with the slag at the higher temperatures. Zirconia dissolution resulted in a slight increase in the solid fraction present in slags at lower temperatures, compared to spinel fraction. Crystal precipitation changed the apparent activation energy and required a longer stabilization times for viscosity measurements. The viscosity results were used in predictive equations based on Veytsman and Einstein's models, with critical nucleation temperatures and the solid fraction calculated with FactSage. In the simulated eastern/western coal feedstock blends based on ash compositions, the fractions of the solid precipitates were also calculated using the thermodynamic program FactSage for each blend composition, and the plastic viscosity of each eastern/western coal slag blend was predicted using Veytsman's model and compared to

  17. Viscosity Determination of Molten Ash from Low-Grade US Coals

    SciTech Connect

    Zhu, Jingxi; Nakano, Jinichiro; Kaneko, Tetsuya Kenneth; Mu, Haoyuan; Bennett, James P.; Kwong, Kyei-Sing; Rozelle, Peter; Sridhar, Seetharaman

    2012-10-01

    In entrained slagging gasifiers, the fluidity of the molten ash is a critical factor for process control since it affects slag formation, the capture of inorganic constituents, refractory wear, and slag drainage along the gasification chamber walls. The use of western coal, or mixtures of eastern and western coals as gasifier feedstock, is likely to occur as western coals become available and technological issues that hinder their use are being resolved. In the present work, the viscosity of synthetic slags with ash chemistries simulating the western U.S. coals, was experimentally measured at a Po2 = 10- 8 atm in the temperature range of 1773–1573 K (1500–1300 °C) using a rotating-bob viscometer. Alumina spindles and containment crucibles of both alumina and zirconia were used. Crystallization studies of this slag using a confocal scanning laser microscope found that a (Mg,Fe)Al2O4-based spinel precipitated at temperatures below 1723 K (1450 °C), and this agreed with FactSage equilibrium phase prediction. The same spinels were observed in the post-viscometry experiment slags when ZrO2 crucibles were used and assumed to be in equilibrium with the slag at the higher temperatures. Zirconia dissolution resulted in a slight increase in the solid fraction present in slags at lower temperatures, compared to spinel fraction. Crystal precipitation changed the apparent activation energy and required a longer stabilization times for viscosity measurements. The viscosity results were used in predictive equations based on Veytsman and Einstein's models, with critical nucleation temperatures and the solid fraction calculated with FactSage. In the simulated eastern/western coal feedstock blends based on ash compositions, the fractions of the solid precipitates were also calculated using the thermodynamic program FactSage for each blend composition, and the plastic viscosity of each eastern/western coal slag blend was

  18. Leaching Behavior of Slags from AN Old Lead Smelter in Chihuahua, Mexico: Metals, Chlorides, Nitrates, Sulfates and Tds Analyses

    NASA Astrophysics Data System (ADS)

    Espejel-Garcia, D.; Wenglas-Lara, G.; Villalobos-Aragon, A.; Espejel-Garcia, V. V.

    2013-05-01

    Waste materials (such as, smelter slags, waste glass, tires, plastics, rubbish, ashes, etc.), have a large potential to substitute natural materials, reducing costs, especially for the construction industry. Smelter slags are resistant and have better compression strength values in comparison to natural aggregates, and generally are far beyond of what the standard ratios need to qualify a material as a good one for construction. But this material has a big problem within it: the existence of toxic elements and compounds in high concentrations, which means that water and soil contamination can be present after water infiltrates through this material; so we perform leaching experiments to characterize and measure the possible contamination under controlled conditions. To perform the slags-leaching experiments, we used an EA-NEN-7375-2004 tank test standard from Netherlands. This test was selected because to our knowledge it is the only one which allows the use of coarse material, as the one utilized in construction. The leaching experiments sampling was performed at different times: 6, 24, 168 and 360 hours, to compare the leachate concentration at the two different pH's values (5 and 8) selected to simulate real conditions. For the leaching experiments, the slags were mixed with natural road base material (gravel-sands from volcanic rocks) at different proportions of 30% and 50%. In order to understand the slags' leaching behavior, other experiments were carried out with the pure material, for both (slags and natural aggregates). After analyses by ICP-OES , the slags from this smelter in Chihuahua contain Pb (0.5 - 4 wt.%), Zn (15-35 wt.%) and As (0.6 wt.%), as well such as: bicarbonates, chlorides, nitrates, sulfates, Mg, K, Na, Ca and TDS. Based on the results of the leaching analyses, via atomic absorption technique, we conclude that Pb and As concentrations are provided by the slags, meanwhile, the bicarbonates, chlorides, Na and Ca are contributed by the road

  19. Stabilization of Oklahoma expensive soils using lime and class C fly ash

    SciTech Connect

    Buhler, R.L.; Cerato, A.B.

    2007-01-15

    This study uses lime and class C fly ash, an industrial byproduct of electric power production produced from burning lignite and subbituminous coal, to study the plasticity reduction in highly expensive natural clays from Idabel, Oklahoma. This study is important, especially in Oklahoma, because most of the native soils are expansive and cause seasonal damage to roadways and structures. The addition of lime or fly ash helps to arrest the shrinkage and swelling behavior of soil. Four soil samples with the same AASHTO classification were used in this study to show shrinkage variability within a soil group with the addition of lime and class C fly ash. The plasticity reduction in this study was quantified using the linear shrinkage test. It was found that soils classified within the same AASHTO group had varying shrinkage characteristics. It was also found that both lime and fly ash reduced the lienar shrinkage, however, the addition of lime reduced the linear shrinkage to a greater degree than the same percentage of class C fly ash. Even though it takes much less lime than fly ash to reduce the plasticity of a highly expansive soil, it may be less expensive to utilize fly ash, which is a waste product of electric power production. Lime also has a lower unit weight than fly ash so weight percentage results may be misleading.

  20. 44. DETAIL VIEW LOOKING EAST AT THE FOUNDATION FOR SLAG ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    44. DETAIL VIEW LOOKING EAST AT THE FOUNDATION FOR SLAG CRUSHER, A DEVICE USED TO REMOVE HARDENED SLAG FROM STEEL LADLES. - John A. Roebling's Sons Company, Kinkora Works, Support Systems, Roebling, Burlington County, NJ

  1. Achieving waste to energy through sewage sludge gasification using hot slags: syngas production

    NASA Astrophysics Data System (ADS)

    Sun, Yongqi; Nakano, Jinichiro; Liu, Lili; Wang, Xidong; Zhang, Zuotai

    2015-06-01

    To relieve the environmental issues of sewage sludge (SS) disposal and greenhouse gas (GHG) emission in China, we proposed an integrated method for the first time to simultaneously deal with these two problems. The hot slags below 920 °C could act as a good heat carrier for sludge gasification and the increasing CO2 concentration in CO2/O2 atmospheres enhanced the production of CO and H2 at 400-800 °C. Three stages of syngas release were clearly identified by Gaussian fittings, i.e., volatile release, char transformation and fixed carbon reaction. Additionally, the effect of sulfur retention of slags and the synergy effect of the stabilization of toxic elements in the solid residuals were discovered in this study. Furthermore, a novel prototype of multiple industrial and urban systems was put forward, in which the produced CO + H2 could be utilized for direct reduced iron (DRI) production and the solid residuals of sludge ash and glassy slags would be applied as cementitious materials. For a steel plant with an annual production of crude steel of 10 million tons in China, the total annual energy saving and GHG emission reduction achieved are 3.31*105 tons of standard coal and 1.74*106 tons of CO2, respectively.

  2. Achieving waste to energy through sewage sludge gasification using hot slags: syngas production.

    PubMed

    Sun, Yongqi; Nakano, Jinichiro; Liu, Lili; Wang, Xidong; Zhang, Zuotai

    2015-01-01

    To relieve the environmental issues of sewage sludge (SS) disposal and greenhouse gas (GHG) emission in China, we proposed an integrated method for the first time to simultaneously deal with these two problems. The hot slags below 920 °C could act as a good heat carrier for sludge gasification and the increasing CO2 concentration in CO2/O2 atmospheres enhanced the production of CO and H2 at 400-800 °C. Three stages of syngas release were clearly identified by Gaussian fittings, i.e., volatile release, char transformation and fixed carbon reaction. Additionally, the effect of sulfur retention of slags and the synergy effect of the stabilization of toxic elements in the solid residuals were discovered in this study. Furthermore, a novel prototype of multiple industrial and urban systems was put forward, in which the produced CO + H2 could be utilized for direct reduced iron (DRI) production and the solid residuals of sludge ash and glassy slags would be applied as cementitious materials. For a steel plant with an annual production of crude steel of 10 million tons in China, the total annual energy saving and GHG emission reduction achieved are 3.31*10(5) tons of standard coal and 1.74*10(6) tons of CO2, respectively. PMID:26074060

  3. Achieving waste to energy through sewage sludge gasification using hot slags: syngas production

    PubMed Central

    Sun, Yongqi; Nakano, Jinichiro; Liu, Lili; Wang, Xidong; Zhang, Zuotai

    2015-01-01

    To relieve the environmental issues of sewage sludge (SS) disposal and greenhouse gas (GHG) emission in China, we proposed an integrated method for the first time to simultaneously deal with these two problems. The hot slags below 920 °C could act as a good heat carrier for sludge gasification and the increasing CO2 concentration in CO2/O2 atmospheres enhanced the production of CO and H2 at 400–800 °C. Three stages of syngas release were clearly identified by Gaussian fittings, i.e., volatile release, char transformation and fixed carbon reaction. Additionally, the effect of sulfur retention of slags and the synergy effect of the stabilization of toxic elements in the solid residuals were discovered in this study. Furthermore, a novel prototype of multiple industrial and urban systems was put forward, in which the produced CO + H2 could be utilized for direct reduced iron (DRI) production and the solid residuals of sludge ash and glassy slags would be applied as cementitious materials. For a steel plant with an annual production of crude steel of 10 million tons in China, the total annual energy saving and GHG emission reduction achieved are 3.31*105 tons of standard coal and 1.74*106 tons of CO2, respectively. PMID:26074060

  4. The improvement of slagging gasifier refractories

    SciTech Connect

    Kwong, K.-S.; Bennett, J.P.; Powell, C.A.; Krabbe, R.A.

    2006-03-01

    Refractories play a vital role in slagging gasifier on-line availability and profitability for the next clean power generation system. A recent survey of gasifier users by USDOE indicated that a longer service life of refractories is the highest need among gasifier operators. Currently, Cr2O3 based refractories, the best of commercially available materials for use in slagging gasifiers, last between 3 and 24 months. Researchers at Albany Research Center (ARC) have identified structural spalling, caused by slag penetration, as one of the major failure mechanisms of Cr2O3 refractories through postmortem analysis. New Cr2O3 refractories with phosphate additives have been developed by ARC to decrease slag penetration and thus structural spalling. Laboratory physical property tests indicated that ARC developed refractories are superior to other commercial bricks. One of the ARC developed phosphate containing refractories has been installed in a slagging gasifier. Preliminary results of the performance of this refractory in the gasifier will be reported along with research to develop non-chromia refractories.

  5. ENHANCEMENT OF STRUCTURAL FOAM MATERIALS BY INCORPORATION OF GASIFIER SLAG

    SciTech Connect

    Olin Perry Norton; Ronald A. Palmer; W. Gene Ramsey

    2006-03-15

    As advanced gasification technology is increasingly adopted as an energy source, disposal of the resulting slag will become a problem. We have shown that gasifier slag can be incorporated into foamed glass, which is currently being manufactured as an abrasive and as an insulating material. The slag we add to foamed glass does not simply act as filler, but improves the mechanical properties of the product. Incorporation of gasifier slag can make foamed glass stronger and more abrasion resistant.

  6. Bonding material containing ashes after domestic waste incineration for cementation of radioactive waste

    SciTech Connect

    Dmitriev, S.A.; Varlakov, A.P.; Gorbunova, O.A.; Arustamov, A.E.; Barinov, A.S.

    2007-07-01

    It is known that cement minerals hydration is accompanied with heat emission. Heat of hardening influences formation of a cement compound structure and its properties. It is important to reduce the heat quantity at continuous cementation of waste and filling of compartments of a repository or containers by a cement grout. For reduction of heating, it is necessary to use cement of mineral additives (fuel ashes, slag and hydraulic silica). Properties of ashes after domestic waste incineration can be similar to ones of fly fuel ashes. However, ash after domestic waste incineration is toxic industrial waste as it contains toxic elements (As, Cd, Hg, Pb, Sb, Zn). Utilization of secondary waste (slag and ash) of combustion plants is an important environmental approach to solving cities' issues. Results of the research have shown that ashes of combustion plants can be used for radioactive waste conditioning. Co-processing of toxic and radioactive waste is ecologically and economically effective. At SIA 'Radon', experimental batches of cement compositions are used for cementation of oil containing waste. (authors)

  7. Effect of Temperature Gradient on Industrial Coal Slag Infiltration into Porous Refractory Materials in Slagging Gasifiers

    SciTech Connect

    Kaneko, Tetsuya Kenneth; Bennett, James P.; Dridhar, Seetharaman

    2011-12-01

    Infiltration characteristics of industrial coal slag into alumina (Al{sub 2}O{sub 3}) refractory material with a temperature gradient induced along the slag's penetration direction are compared to those obtained under near-isothermal conditions. Experiments were conducted with a hot-face temperature of 1450°C and a CO/CO{sub 2} ratio of 1.8, which corresponds to an oxygen partial pressure of ~10{sup −8} atm. The refractory under the near-isothermal temperature profile, with higher average temperatures, demonstrated a greater penetration depth than its counterpart that was under the steeper temperature gradient. Slag that did not infiltrate into the refractory due to the induced temperature gradient, pooled and solidified on the top of the sample. Within the pool, a conglomerated mass of troilite (FeS) formed separately from the surrounding slag. Microscopy of the cross-sectioned infiltrated refractories revealed that the slag preferentially corroded the matrix regions closer to the top surface. Furthermore, the formation of a thick layer of hercynite (FeAl{sub 2}O{sub 4}) at the top of refractory/slag interface significantly depleted the slag of its iron-oxide content with respect to its virgin composition. A qualitative description of the penetration process is provided in this article.

  8. Mercury capture by selected Bulgarian fly ashes: Influence of coal rank and fly ash carbon pore structure on capture efficiency

    USGS Publications Warehouse

    Kostova, I.J.; Hower, J.C.; Mastalerz, Maria; Vassilev, S.V.

    2011-01-01

    Mercury capture by fly ash C was investigated at five lignite- and subbituminous-coal-burning Bulgarian power plants (Republika, Bobov Dol, Maritza East 2, Maritza East 3, and Sliven). Although the C content of the ashes is low, never exceeding 1.6%, the Hg capture on a unit C basis demonstrates that the low-rank-coal-derived fly ash carbons are more efficient in capturing Hg than fly ash carbons from bituminous-fired power plants. While some low-C and low-Hg fly ashes do not reveal any trends of Hg versus C, the 2nd and, in particular, the 3rd electrostatic precipitator (ESP) rows at the Republika power plant do have sufficient fly ash C range and experience flue gas sufficiently cool to capture measurable amounts of Hg. The Republika 3rd ESP row exhibits an increase in Hg with increasing C, as observed in other power plants, for example, in Kentucky power plants burning Appalachian-sourced bituminous coals. Mercury/C decreases with an increase in fly ash C, suggesting that some of the C is isolated from the flue gas stream and does not contribute to Hg capture. Mercury capture increases with an increase in Brunauer-Emmett-Teller (BET) surface area and micropore surface area. The differences in Hg capture between the Bulgarian plants burning low-rank coal and high volatile bituminous-fed Kentucky power plants suggests that the variations in C forms resulting from the combustion of the different ranks also influence the efficiency of Hg capture. ?? 2010 Elsevier Ltd.

  9. Activation of fly ash

    DOEpatents

    Corbin, David R.; Velenyi, Louis J.; Pepera, Marc A.; Dolhyj, Serge R.

    1986-01-01

    Fly ash is activated by heating a screened magnetic fraction of the ash in a steam atmosphere and then reducing, oxidizing and again reducing the hydrothermally treated fraction. The activated fly ash can be used as a carbon monoxide disproportionating catalyst useful in the production of hydrogen and methane.

  10. Magnetism of cigarette ashes

    NASA Astrophysics Data System (ADS)

    Jordanova, Neli; Jordanova, Diana; Henry, Bernard; Le Goff, Maxime; Dimov, Dimo; Tsacheva, Tsenka

    2006-06-01

    Mineral composition of cigarette ashes is well studied in the literature, but no reports are available about the magnetic fraction. Our study presents an investigation of the basic magnetic characteristics of ashes from several commercially available cigarette brands and a wood ash. Magnetic susceptibility, which is a concentration-dependent parameter in case of uniform mineralogy, shows that cigarette ashes contain relatively high amount of magnetic iron minerals, similar to that in wood ash from our study and other literature data. Magnetization data suggest that cigarette ashes contain some 0.1 wt% or lower quantity of magnetite, depending on the brand. Analyses of magnetic mineralogy imply that the main magnetic minerals in ashes from higher quality cigarette brands are magnetite and iron carbide cementite, while in ashes from lower quality brands without additives magnetic minerals are pure and substituted with foreign ions magnetite. Magnetic grain-size analysis shows that cigarette ashes contain significant amount of very fine, nano-meter sized magnetic particles, as well as coarser (up to several microns), magnetically stable grains. Thus, the magnetic study of cigarette ashes proved that these plant ashes possess non-negligible magnetic properties. The results could serve for better elucidation of mineralogy of cigarette ashes as a whole, as well as for future investigation on the presence of magnetic ultra fine particles in cigarette smoke, which may be inhaled in lungs during smoking.

  11. Activation of fly ash

    DOEpatents

    Corbin, D.R.; Velenyi, L.J.; Pepera, M.A.; Dolhyj, S.R.

    1986-08-19

    Fly ash is activated by heating a screened magnetic fraction of the ash in a steam atmosphere and then reducing, oxidizing and again reducing the hydrothermally treated fraction. The activated fly ash can be used as a carbon monoxide disproportionating catalyst useful in the production of hydrogen and methane.

  12. Improved thermocouple assemblies for slagging gasifiers

    SciTech Connect

    Chinn, Richard E.; Bennett, James P.; Dahlin, Cheryl L.; Dogan, Cynthia P.; Kwong, Kyei-Sing; Petty, Arthur V.

    2002-09-01

    The thermocouple devices currently employed to monitor temperatures in slagging coal gasifiers typically fail within a few weeks of exposure to the harsh operating environment. As a result, gasifier operators are often left to optimize their system’s performance without precise knowledge of the gasifier operating temperature. Engineers at the Albany Research Center are exploring ways to extend thermocouple life in gasifier environments by enhancing the thermocouple assembly’s resistance to slag penetration and attack. In this presentation, several strategies will be examined that can reduce thermocouple susceptibility to corrosive attack by coal slag, including the use of barrier coatings and improved filler materials. The relative effectiveness of these techniques in laboratory exposure tests will be discussed.

  13. Modeling of viscosities of the partly crystallized slags in the Al2O3-CaO-``FeO''-SiO2 system

    NASA Astrophysics Data System (ADS)

    Kondratiev, Alex; Jak, Evgueni

    2001-12-01

    A viscosity model of the partly crystallized slag in the Al2O3-CaO-‘FeO’-SiO2 system has been developed in conjunction with the thermodynamic computer package F*A*C*T. Proportions of solids crystallized out of the liquid phase and compositions of the remaining liquid phase predicted by F*A*C*T are used in the viscosity model. Various heterogeneous viscosity models have been tested using large experimental dataset in the Al2O3-CaO-‘FeO’-SiO2 system in reducing conditions close to the equilibrium with metallic iron. The Roscoe equation with new empirical parameters was found to provide reasonable agreement with experimental data. Examples of model application to industrial nonferrous smelting slag systems are presented. This model can also be applied to coal ash slags.

  14. Chemical characterization of high-temperature arc gasification slag with a focus on element release in the environment.

    PubMed

    Roessler, Justin G; Oehmig, Wesley N; Blaisi, Nawaf I; Townsend, Timothy G

    2014-07-15

    High-temperature arc gasification (HTAG) has been proposed as a viable technology for the generation of energy and the production of saleable byproducts from municipal solid waste (MSW). Total concentrations of elements in HTAG slag were assessed and indicated a high partitioning of trace elements (Pb, Cd, and As) into the flue gas, an issue of concern when assessing the air pollution control residues (APCR) status as a hazardous waste. Hazardous waste leaching tests [such as the toxicity characteristic leaching procedure (TCLP)] were performed and confirmed that the slag did not meet U.S. criteria for a hazardous waste. Leaching was assessed using batch and column tests; the results revealed that Sb and Al were elevated in respect to risk-based regulatory thresholds. Slag samples were carbonated to simulate weathering effects, and although leachable concentrations of Al did decrease by an order of magnitude, Sb concentrations were found to increase. Low total concentrations of certain trace elements (As, Cd, and Pb), with respect to MSW incineration bottom ashes support the potential for reuse of HTAG slag; however, leaching of elements (Pb, Al, and Sb) in batch and column tests indicate that proper engineering controls would need to be taken to ensure protection of water supplies in a reuse application. PMID:24912855

  15. Update on cost differentials - lignite versus other coals

    SciTech Connect

    Gorman, P.F.

    1983-11-01

    Renewed interest in solid fossil fuels has developed a strongly competitive market environment for coals and lignites of widely different physical and chemical properties. In addressing this situation, both utility planners and fuel suppliers face decisions involving, simultaneously, the combustibles characteristics and relative pricing. This paper discusses the influence of fuel properties on capital, operating and maintenance costs, and proposes a method for preliminary economic evaluations of competing fuels focusing on heating value and sulfur content. The analysis performed suggests that exclusion of other properties, or their indirect assessment through the heating value, does not introduce significant distortion to the comparison. A procedure correlating fuel characteristics and electricity busbar costs is developed to assist the quick determination of competitive pricing ranges between fuels. A specific application of this approach quantifies the current degree of attractiveness of lignites as an energy source for electrical power generation in the Gulf Coast Region.

  16. Oxydesulfurization of a Turkish lignite using trona solutions

    SciTech Connect

    Yaman, S.; Kuecuekbayrak, S.

    1996-06-01

    This article investigates the possibility of using trona minerals in the oxydesulfurization of coal. The experiments were performed on a Turkish lignite having high organic and high pyritic sulfur content from the Gediz area. Oxydesulfurization of the lignite sample using trona minerals was studied at 423--473 K, under 0--1 MPa oxygen partial pressure at 0--0.3 M equivalent alkalinity of Na{sub 2}CO{sub 3} for 2.5--60 min. Almost all of the pyritic sulfur content and, depending on the working conditions, an important part of the organic sulfur content were removed. Unless the temperature reached 473 K, solid product yield was not negatively affected. Trona minerals were seen as a suitable alkaline to use in oxydesulfurization of coal.

  17. Use of North Dakota lignite in advanced power systems

    SciTech Connect

    Willson, W.G.; Hurley, J.P.; Sharp, L.

    1992-12-01

    In order to develop critical data for Department of Energy (DOE) and private industry for advanced high-efficiency power systems using North Dakota lignite in pressurized gasification and combustion systems, tests were performed in bench-scale equipment at the Energy and Environmental Research Center (EERC). The primary objectives were to (1) determine the conversion levels for Center ND lignite under pressurized fluid-bed gasification conditions with sorbent addition as a function of temperature, (2) determine the sulfur capture using limestone or dolomite under gasification conditions giving 90% or higher carbon conversion, (3) evaluate char/coal conversion and sulfur capture in a pressurized fluid-bed combustor, (4) assess the potential for bed agglomeration under the preferred operating conditions for both systems.

  18. Beneficiation of Turkish lignites by thermal treatment and magnetic separation

    SciTech Connect

    Onal, G.; Renda, D.; Mustafaev, I.; Dogan, Z.

    1999-07-01

    In this paper, the improvement of Turkish lignites by semi-coking and REMS magnetic separation, in two stages, is discussed. The oxidation and decomposition of pyrite through the thermal treatment result in the formation of iron oxide and pyrrhotite on the surface. In addition to pyrite, part of the organic sulfur is also removed. After thermal treatment of lignites at temperatures ranging from 370 to 650 C, the application of REMS magnetic separator produces a product higher in calorific value and lower in sulfur content. The product can be utilized after briquetting. The volatile gases can also be used after sulfur removal. This process appears to be feasible as a clean coal manufacture from the point of energy efficiency. A short economic analysis is also presented.

  19. Refractory liner materials used in slagging gasifiers

    SciTech Connect

    Bennett, James P.

    2004-09-01

    Refractory liners are used on the working face of entrained flow slagging gasifiers that react coal, petroleum coke, or other carbon feedstock with oxygen and water. The refractory liners protect the gasifier shell from elevated temperatures, corrosive slags, and thermal cycling during gasification. Refractory failure is primarily by two means, corrosive dissolution and spalling. High chrome oxide refractory materials have evolved as the material of choice to line the hot face of gasifiers, yet the performance of these materials does not meet the service requirements of industry. A review of gasifier liner materials, their evolution, issues impacting their performance, and future research direction are discussed.

  20. Advanced ash management technologies for CFBC ash.

    PubMed

    Anthony, E J; Berry, E E; Blondin, J; Bulewicz, E M; Burwell, S

    2003-01-01

    The combustion of high-sulphur coal demands the reduction of sulphur emissions. The sorbent most often used in sulphur capture technology is calcium-based. Ashes from technologies such as circulating fluidized bed combustion (CFBC), therefore, contain high calcium levels. The use and disposal of these ashes poses challenges, because of highly exothermic reactions with water, high-pH leachates, and excessive expansion of solidified materials. This paper looks at the potential of two post-combustion ash treatment processes, CERCHAR hydration and AWDS disposal, in solving these challenges. A high-sulphur coal-derived CFBC ash is examined, after CERCHAR hydration treatment, in conjunction with a conventionally hydrated ash, in a range of chemical, geotechnical and utilization scenarios. The ashes are used to make no-cement and roller-compacted concrete as well as Ash Water Dense Suspensions (AWDS). The solidified mortar paste from no-cement concrete is subjected to an extensive geochemical examination to determine how solidification progresses and strength develops, from a chemical point of view. PMID:12909091

  1. Alkylation of lignites and peat in low-temperature plasma

    SciTech Connect

    L.I. Shchukin; S.I. Zherebtsov; M.V. Kornievich; O.A. Skutina

    2007-02-15

    The alkylation of lignites and peat was carried out at 50-270{sup o}C in different plasmas. The degree of conversion determined as the yield of the alcohol-benzene extract increases on passing from methane to alcohol plasma. The dependence of the extract yield on the plasma temperature, treatment time, and sample grinding degree was studied. 5 refs., 4 figs., 2 tabs.

  2. Distribution of heavy metals from iron bath-melting separation process applied to municipal solid waste incineration fly ash.

    PubMed

    Wei, C M; Liu, Q C; Wen, J

    2009-12-14

    Fly ash generated from municipal solid waste (MSW) incineration is frequently classified as hazardous material and requires special disposal. The management of the large amount of fly ash has caused increasing problems in China. This work describes a novel approach for melting MSW incineration fly ash, and the distribution of heavy metals was characterized during the iron bath-melting separation process. Four hundred grams of pelletized fly ash was fed into the furnace in molten iron bath atmosphere. After the melting separation process, the distribution of heavy metals in samples and the leaching characteristics of the slag were investigated. The results indicated that iron bath-melting promoted the transfer of Cr, Mn and Cu from the slag phase to the iron phase, which also improved Zn and Pb volatilization. The leaching concentrations, determined by the Chinese Standard Method (rollover leaching procedure) of the target metals of the slag from leaching tests were lower than the Chinese regulatory thresholds. Therefore, this method was proposed as an environmentally friendly technology to achieve a satisfactory solution for MSW incineration fly ash management. PMID:20183994

  3. Arsenic and copper stabilisation in a contaminated soil by coal fly ash and green waste compost.

    PubMed

    Tsang, Daniel C W; Yip, Alex C K; Olds, William E; Weber, Paul A

    2014-09-01

    In situ metal stabilisation by amendments has been demonstrated as an appealing low-cost remediation strategy for contaminated soil. This study investigated the short-term leaching behaviour and long-term stability of As and Cu in soil amended with coal fly ash and/or green waste compost. Locally abundant inorganic (limestone and bentonite) and carbonaceous (lignite) resources were also studied for comparison. Column leaching experiments revealed that coal fly ash outperformed limestone and bentonite amendments for As stabilisation. It also maintained the As stability under continuous leaching of acidic solution, which was potentially attributed to high-affinity adsorption, co-precipitation, and pozzolanic reaction of coal fly ash. However, Cu leaching in the column experiments could not be mitigated by any of these inorganic amendments, suggesting the need for co-addition of carbonaceous materials that provides strong chelation with oxygen-containing functional groups for Cu stabilisation. Green waste compost suppressed the Cu leaching more effectively than lignite due to the difference in chemical composition and dissolved organic matter. After 9-month soil incubation, coal fly ash was able to minimise the concentrations of As and Cu in the soil solution without the addition of carbonaceous materials. Nevertheless, leachability tests suggested that the provision of green waste compost and lignite augmented the simultaneous reduction of As and Cu leachability in a fairly aggressive leaching environment. These results highlight the importance of assessing stability and remobilisation of sequestered metals under varying environmental conditions for ensuring a plausible and enduring soil stabilisation. PMID:24859701

  4. Slag processing system for direct coal-fired gas turbines

    DOEpatents

    Pillsbury, Paul W.

    1990-01-01

    Direct coal-fired gas turbine systems and methods for their operation are provided by this invention. The systems include a primary combustion compartment coupled to an impact separator for removing molten slag from hot combustion gases. Quenching means are provided for solidifying the molten slag removed by the impact separator, and processing means are provided forming a slurry from the solidified slag for facilitating removal of the solidified slag from the system. The released hot combustion gases, substantially free of molten slag, are then ducted to a lean combustion compartment and then to an expander section of a gas turbine.

  5. Simulation of slag control for the Plasma Hearth Project

    SciTech Connect

    Power, M.A.; Carney, K.P.; Peters. G.G.

    1996-12-31

    The goal of the Plasma Hearth Project is to stabilize alpha-emitting radionuclides in a vitreous slag and to reduce the effective storage volume of actinide-containing waste for long-term burial. The actinides have been shown to partition into the vitreous slag phase of the melt. The slag composition may be changed by adding glass-former elements to ensure that this removable slag has the most desired physical and chemical properties for long-term burial. A data acquisition and control system has been designed to regulate the composition of five elements in the slag.

  6. Limitation of Sulfide Capacity Concept for Molten Slags

    NASA Astrophysics Data System (ADS)

    Jung, In-Ho; Moosavi-Khoonsari, Elmira

    2016-04-01

    The sulfide capacity concept has been widely used in pyrometallurgy to define sulfur removal capacities of slags. Typically, the sulfide capacity is considered to be a unique slag property depending only on temperature regardless of partial pressures of oxygen and sulfur. In the present study, it is demonstrated that sulfide capacities of slags in particular those of Na2O-containing slags can vary with partial pressures of oxygen and sulfur due to large solubility of sulfide in Na2O-containing slag systems.

  7. Sulfur removal from Gediz lignite using aqueous sodium hydroxide solutions under mild oxidative conditions

    SciTech Connect

    Yaman, S.; Kuecuekbayrak, S.

    1999-11-01

    Sulfur removal from a high-sulfur Turkish lignite (Gediz) using aqueous sodium hydroxide solutions having dissolved oxygen was investigated under mild oxidative conditions. Effects of the parameters such as sodium hydroxide/lignite weight ratio, temperature, and partial pressure of oxygen were investigated within the ranges of 0.05--0.8, 423--498 K, and 1--2 MPa, respectively. Optimum values of these parameters were determined regarding sulfur removal and coal recovery. Influences of dry oxidation of the lignite sample as a pretreatment at 573 K and subsequent washing of some treated lignite samples with 1 N HCl were investigated.

  8. JV Task 98 - Controlling Mercury Emissions for Utilities Firing Lignites from North America

    SciTech Connect

    Steven Benson

    2007-06-15

    This project compiled and summarized the findings and conclusions of research, development, and demonstration projects on controlling mercury from lignite coals. A significant amount of work has been conducted since 1994 on mercury in lignite, mercury measurement in flue gases, sorbent, sorbent enhancement additives, oxidation agent development, and full-scale demonstration of mercury control technologies. This report is focused on providing the lignite industry with an understanding of mercury issues associated with the combustion of lignite, as well as providing vital information on the methods to control mercury emissions in coal-fired power plants.

  9. Assessment of the radiological impact of coal utilization. II. Radionuclides in western coal ash

    SciTech Connect

    Styron, C.E.; Bishop, C.T.; Casella, V.R.; Jenkins, P.H.; Yanko, W.H.

    1981-04-03

    A project has been initiated at Mound Facility specifically to evaluate the potential radiological impact of coal utilization. Phase I of the project included a survey of western US coal mines and an assessment of emissions from a power plant burning Western coal. Concentrations of uranium in coal from operating Western mines were slightly below the national average and roughly comparable to Eastern coal. Environmental deposition of radionuclides from stack emissions over a 20-year accumulation at a power plant burning Western coal was estimated to be 0.1 to 1.0% of measured background. Phase II of the project, the subject of the present report, has involved an interlaboratory comparison of results of radioanalytical procedures, determining partitioning coefficients for radionuclides in bottom ash and fly ash, and an assessment of the potential for migration of radionuclides from ash disposal sites. Results from the various laboratories for uranium-238, uranium-234, thorium-230, radium-226, polonium-210, thorium-232, thorium-228, and uranium-235 were generally in very good agreement. However, values for lead-210 in coal varied widely. Essentially all the nonvolatile radionuclides (uranium, radium, and thorium) from feed coal were accounted for in fly ash and bottom ash. However, 20 to 50% of the volatile radionuclides (lead and polonium) from subbituminous and lignitic coals could not be accounted for in ash, and it is assumed that this fraction exits via the stack. At the power plant burning bituminous coal, essentially all the lead and most of the polonium remained with the ash.

  10. Characterizing coal-gasifier slag-refractory interactions

    SciTech Connect

    Rawers, J.; Kwong, J.; Bennett, J.

    1999-07-01

    To characterize refractory degradation and loss on commercial coal-gasifier combined cycle powder generating facilities, cup-type tests were conducted on high chromium-alumina, sinter-bonded refractories under laboratory conditions designed to simulate commercial operations of temperature, atmosphere, and slag interactions. These tests provided qualitative results from which the slag-refractory interactions can be characterized. These high chromium refractories were generally inert with respect to the coal slag components. However, this study did show (1) iron (oxide) in the slag reacted with chrome sesquioxide to produce a Cr-Fe spinel at the slag-refractory interface, and (2) chrome was soluble in the molten slag. Comparison of cup-type test results with data from operating commercial plants suggests that the principal loss of refractory material in a coal-gasifier combustion chamber is chrome dissolution into the slag. Tests are currently underway to determine if minor modifications to the combustion process might increase refractory life.

  11. THERMOCHEMICAL MODELING OF REFRACTORY CORROSION IN SLAGGING COAL GASIFIERS

    SciTech Connect

    Besmann, Theodore M

    2008-01-01

    Slagging coal gasifiers suffer corrosive attack on the refractory liner and these interactions were thermochemically simulated. The slag is observed to penetrate the refractory, which complicates modeling the phase behavior of the slag-penetrated interior of the refractory. A simple strategy was adopted such that step-wise changes in composition with decreasing slag content were assumed to account for the compositional changes as slag penetrates the refractory. The thermochemical equilibrium calculations following this strategy typically yielded three solution phases as well as the stoichiometric crystalline phases AlPO4 and Ca3(PO4)2 depending on composition/penetration. Under some conditions a slag liquid miscibility gap exists such that two slag liquids co-exist.

  12. Melting of municipal solid waste incinerator fly ash by waste-derived thermite reaction.

    PubMed

    Wang, Kuen-Sheng; Lin, Kae-Long; Lee, Ching-Hwa

    2009-02-15

    This work describes a novel approach for melting municipal solid waste incinerator (MSWI) fly ash, based on self-propagating reactions, by using energy-efficient simulated waste-derived thermite. The self-propagating characteristics, the properties of the recycled alloy and slag and the partitioning of heavy metals during the process are also studied. Experimental results demonstrate that the mix ratio of fly ash to the starting mixture of less than 30% supports the development of the self-propagating reaction with a melting temperature of 1350-2200 degrees C. Furthermore, metallic iron (or alloy) and the slag were retrieved after activation of the thermite reactions among the starting mixtures. It was noted that more than 91wt.% of iron was retrieved as alloy and the rest of non-reductive oxides as slag. During the thermite reactions, the partition of heavy metals to the SFA and flue gas varied with the characteristics of the target metals: Cd was mainly partitioned to flue gas (75-82%), and partition slightly increased with the increasing fly ash ratio; Pb and Zn, were mainly partitioned to the SFA, and the partition increased with increasing fly ash ratio; Cu was partitioned to the SFA (18-31%) and was not found in the flue gas; and moreover stable Cr and Ni were not identified in both the SFA and flue gas. On the other hand, the determined TCLP leaching concentrations were all well within the current regulatory thresholds, despite the various FA ratios. This suggests that the vitrified fly ash samples were environmental safe in heavy metal leaching. The results of this study suggested that melting of municipal solid waste incinerator fly ash by waste-derived thermite reactions was a feasible approach not only energy-beneficial but also environmental-safe. PMID:18573610

  13. Decalcification resistance of alkali-activated slag.

    PubMed

    Komljenović, Miroslav M; Baščarević, Zvezdana; Marjanović, Nataša; Nikolić, Violeta

    2012-09-30

    This paper analyses the effects of decalcification in concentrated 6M NH(4)NO(3) solution on mechanical and microstructural properties of alkali-activated slag (AAS). Portland-slag cement (CEM II/A-S 42.5 N) was used as a benchmark material. Decalcification process led to a decrease in strength, both in AAS and in CEM II, and this effect was more pronounced in CEM II. The decrease in strength was explicitly related to the decrease in Ca/Si atomic ratio of C-S-H gel. A very low ratio of Ca/Si ~0.3 in AAS was the consequence of coexistence of C-S-H(I) gel and silica gel. During decalcification of AAS almost complete leaching of sodium and tetrahedral aluminum from C-S-H(I) gel also took place. AAS showed significantly higher resistance to decalcification in relation to the benchmark CEM II due to the absence of portlandite, high level of polymerization of silicate chains, low level of aluminum for silicon substitution in the structure of C-S-H(I), and the formation of protective layer of polymerized silica gel during decalcification process. In stabilization/solidification processes alkali-activated slag represents a more promising solution than Portland-slag cement due to significantly higher resistance to decalcification. PMID:22818592

  14. Prospects for using the fly ash produced at thermal power plants in the Rostov region

    NASA Astrophysics Data System (ADS)

    Fedorova, N. V.; Shaforost, D. A.

    2015-01-01

    A detailed analysis of the chemical composition of the fuel mineral component and admixtures in ash and slag materials is presented taking as an example some of coal-fired thermal power plants in the Rostov region. The physicochemical properties of ash and slag components from different coals that are of interest for industrial use are considered together with methods for separating them. The list of such components includes hollow aluminum silicate microspheres, inert mass of aluminum silicate composition, magnetite microballs, unburned coal particles, carbonate microspheres, heavy fraction containing ferrosilicium, admixtures of noble metals and rare and trace elements. Various ways of using these components directly at thermal power plants and enterprises in the Rostov region are proposed.

  15. Application of thermal plasma to vitrify fly ash from municipal solid waste incinerators.

    PubMed

    Wang, Qin; Yan, Jian-Hua; Chi, Yong; Li, Xiao-Dong; Lu, Sheng-Yong

    2010-01-01

    Several fly ash samples collected from different municipal solid waste incinerator plants were vitrified using thermal plasma furnace at 1400-1500 degrees C. After vitrification, there are obvious changes in microstructures and crystalline phases between produced slag and original ash. Toxicity characteristic leaching procedure results show that there is an excellent resistance against leaching of heavy metal ions. The residual fractions of heavy metals in slag presumably decrease in the following sequence: Cr>Ni>Cu>Zn>Pb>Cd. Almost all of PCDD/Fs could be destroyed through thermal plasma treatment. And the average decomposition efficiency of the samples vitrified by thermal plasma furnace is 100% in toxic equivalent calculations, higher than that of the samples vitrified by conventional resistance furnace. PMID:20004931

  16. Fly ash carbon passivation

    DOEpatents

    La Count, Robert B; Baltrus, John P; Kern, Douglas G

    2013-05-14

    A thermal method to passivate the carbon and/or other components in fly ash significantly decreases adsorption. The passivated carbon remains in the fly ash. Heating the fly ash to about 500 and 800 degrees C. under inert gas conditions sharply decreases the amount of surfactant adsorbed by the fly ash recovered after thermal treatment despite the fact that the carbon content remains in the fly ash. Using oxygen and inert gas mixtures, the present invention shows that a thermal treatment to about 500 degrees C. also sharply decreases the surfactant adsorption of the recovered fly ash even though most of the carbon remains intact. Also, thermal treatment to about 800 degrees C. under these same oxidative conditions shows a sharp decrease in surfactant adsorption of the recovered fly ash due to the fact that the carbon has been removed. This experiment simulates the various "carbon burnout" methods and is not a claim in this method. The present invention provides a thermal method of deactivating high carbon fly ash toward adsorption of AEAs while retaining the fly ash carbon. The fly ash can be used, for example, as a partial Portland cement replacement in air-entrained concrete, in conductive and other concretes, and for other applications.

  17. Chemical composition and some trace element contents in coals and coal ash from Tamnava-Zapadno Polje Coal Field, Serbia

    SciTech Connect

    Vukasinovic-Pesic, V.; Rajakovic, L.J.

    2009-07-01

    The chemical compositions and trace element contents (Zn, Cu, Co, Cr, Ni, Pb, Cd, As, B, Hg, Sr, Se, Be, Ba, Mn, Th, V, U) in coal and coal ash samples from Tamnava-Zapadno Polje coal field in Serbia were studied. The coal from this field belongs to lignite. This high volatility coal has high moisture and low S contents, moderate ash yield, and high calorific value. The coal ash is abundant in alumosilicates. Many trace elements such as Ni > Cd > Cr > B > As > Cu > Co > Pb > V > Zn > Mn in the coal and Ni > Cr > As > B > Cu > Co = Pb > V > Zn > Mn in the coal ash are enriched in comparison with Clarke concentrations.

  18. Investigation of pyrite as a contributor to slagging in eastern bituminous coals. Quarterly progress report 9, October 1-December 31, 1983

    SciTech Connect

    Bryers, R.W.

    1984-06-01

    The objective of this program is to examine slags formed as a result of firing coals with varying concentration levels, size distribution, and orientation of pyrite with regard to mineral matter in the coal in a laboratory furnace. The program tasks are: (1) selection of eight candidate coals; (2) chemical characterization of the coal samples and identification of the pyrite size, distribution, and orientation with respect to other mineral matter and concentration levels; (3) testing of the candidate coals in a laboratory furnace; (4) chemical and physical characterization of the slag and fly ash samples created by the impurities in the coal sample; (5) influence of coal beneficiation on furnace slagging; and (6) analysis of data and identification of parameters influencing the contribution of pyrite to slagging problems. Washing of the Upper Freeport coal from Indiana County, Pennsylvania, was completed by the last quarter of 1983. The washed product was characterized for mineral content, and a combustion test was performed. Kentucky No. 9 from Henderson County, Kentucky, selected as the sixth coal to be investigated, was characterized using size and gravity fractionation techniques and was combusted in the laboratory furnace to evaluate its slagging and fouling potential. The remaining two coals to be characterized and combusted were identified as Illinois No. 5 and Lower Kittanning from Clarion County, Pennsylvania. 80 figures, 27 tables.

  19. Investigation of pyrite as a contributor to slagging in Eastern Bituminous coals. Quarterly progress report 10, January 1-March 30, 1984

    SciTech Connect

    Bryers, R.W.

    1984-06-01

    The objective of this program is to examine slags formed as a result of firing coals with varying concentration levels, size distribution, and orientation of pyrite with regard to mineral matter in the coal in a laboratory furnace. The program tasks are: (1) selection of eight candidate coals; (2) chemical characterization of the coal samples and identification of the pyrite size, distribution, and orientation with respect to other mineral matter and concentration levels; (3) testing of the candidate coals in a laboratory furnace; (4) chemical and physical characterization of the slag and fly ash samples created by the impurities in the coal sample; (5) influence of coal beneficiation on furnace slagging; and (6) analysis of data and identification of parameters influencing the contribution of pyrite to slagging problems. Results of analysis of two coals, Illinois No. 5 Gallatin County, Illinois and Lower Kittaning Clarion County, Pennsylvania, are presented. Examination of the morphology of furnace slag deposited in the 100 lb/hr combustor, as well as industrial furnace, revealed reocurring crystals of iron of pyrite origin on the surface of the deposit. The cubic, octahedron and cubic/octahedron crystals are similar in size and structure to pyrite crystals occasionally found in coal. To characterize the morphology of pyrites within the coal samples of Illinois No. 5 and Lower Kittaning coals were examined using SEM and EDAX analysis. Results are presented of the types of minerals found. 10 figures, 3 tables.

  20. Photosynthetic pigment concentrations, gas exchange and vegetative growth for selected monocots and dicots treated with two contrasting coal fly ashes

    SciTech Connect

    Yunusa, I.A.M.; Burchett, M.D.; Manoharan, V.; DeSilva, D.L.; Eamus, D.; Skilbeck, C.G.

    2009-07-15

    There is uncertainty as to the rates of coal fly ash needed for optimum physiological processes and growth. In the current study we tested the hyothesis that photosynthetic pigments concentrations and CO{sub 2} assimilation (A) are more sensitive than dry weights in plants grown on media amended with coal fly ash. We applied the Terrestrial Plant Growth Test (Guideline 208) protocols of the Organization for Economic Cooperation and Development (OECD) to monocots (barley (Hordeum vulgare) and ryegrass (Secale cereale)) and dicots (canola (Brasica napus), radish (Raphanus sativus), field peas (Pisum sativum), and lucerne (Medicago sativa)) on media amended with fly ashes derived from semi-bituminous (gray ash) or lignite (red ash) coals at rates of 0, 2.5, 5.0, 10, or 20 Mg ha(-1). The red ash had higher elemental concentrations and salinity than the gray ash. Fly ash addition had no significant effect on germination by any of the six species. At moderate rates ({<=}10 Mg ha{sup -1}) both ashes increased (P < 0.05) growth rates and concentrations of chlorophylls a and b, but reduced carotenoid concentrations. Addition of either ash increased A in radish and transpiration in barley. Growth rates and final dry weights were reduced for all of the six test species when addition rates exceeded 10 Mg ha{sup -1} for gray ash and 5 Mg ha{sup -1} for red ash. We concluded that plant dry weights, rather than pigment concentrations and/or instantaneous rates of photosynthesis, are more consistent for assessing subsequent growth in plants supplied with fly ash.

  1. Slag remelt purification of irradiated vanadium alloys

    SciTech Connect

    Carmack, W.J.; Smolik, G.R.; McCarthy, K.A.; Gorman, P.K.

    1995-07-01

    This paper describes theoretical and scoping experimental efforts to investigate the decontamination potential of a slag remelting process for decontaminating irradiated vanadium alloys. Theoretical calculations, using a commercial thermochemical computer code HSC Chemistry, determined the potential slag compositions and slag-vanadium alloy ratios. The experiment determined the removal characteristics of four surrogate transmutation isotopes (Ca, Y - to simulate Sc, Mn, and Ar) from a V-5Ti-5Cr alloy with calcium fluoride slag. An electroslag remelt furnace was used in the experiment to melt and react the constituents. The process achieved about a 90 percent removal of calcium and over 99 percent removal of yttrium. Analyses indicate that about 40 percent of the manganese may have been removed. Argon analyses indicates that 99.3% of the argon was released from the vanadium alloy in the first melt increasing to 99.7% during the second melt. Powder metallurgy techniques were used to incorporate surrogate transmutation products in the vanadium. A powder mixture was prepared with the following composition: 90 wt % vanadium, 4.7 wt % titanium, 4.7 wt % chromium, 0.35 wt % manganese, 0.35 wt % CaO, and 0.35 wt % Y{sub 2}O{sub 3}. This mixture was packed into 2.54 cm diameter stainless steel tubes. Argon was introduced into the powder mixture by evacuating and backfilling the stainless steel containers to a pressure of 20 kPa (0.2 atm). The tubes were hot isostatically pressed at 207 MPa (2000 atm) and 1473 K to consolidate the metal. An electroslag remelt furnace (crucible dimensions: 5.1 cm diameter by 15.2 cm length) was used to process the vanadium electrodes. Chemical analyses were performed on samples extracted from the slags and ingots. Ingot analyses results are shown below. Values are shown in percent removal of the four targeted elements of the initial compositions.

  2. Effect of SiO2 on immobilization of metals and encapsulation of a glass network in slag.

    PubMed

    Kuo, Yi-Ming; Lin, Ta-Chang; Tsai, Perng-Jy

    2003-11-01

    The final disposal of ash from an incinerator is of special concern because of the possibility of its releasing toxic substances. Melting/vitrification has been regarded as a prospective technology of ash treatment. The object of this investigation was to evaluate the effect of silica (SiO2) addition on the immobilization of hazardous metals and the encapsulation of a glass network during the vitrification process. Four specimens with SiO2/fly ash mixing ratios of 0, 0.1, 0.2, and 0.3, respectively, were tested. The mobility of metals in slag was then estimated by a sequential extraction procedure. X-ray diffraction analysis indicates that SiO2 leads to the polymerization of silicates. The encapsulation of aluminum, calcium, and magnesium would not be observed unless adequate amount of SiO2 was added. It was also found that SiO2 addition enhances the formation of a compact and interconnected glass network structure and, thus, contributes to the chemical stability of metals in slag. After vitrification, the mobility of cadmium, copper, iron, chromium, nickel, lead, and zinc was significantly reduced. However, there is no significant correlation between the immobilization of these metals and the addition of SiO2. PMID:14649761

  3. Direct utilization - recovery of minerals from coal fly ash. Technical progress report, October 1, 1982-December 31, 1982

    SciTech Connect

    Burnet, G.; Murtha, M.J.; Seaverson, L.M.

    1983-02-01

    Research included an examination of the adsorbed water on coal fly ash, the utilization of phosgene as a chlorination agent, the physical adsorption and chemisorption of phosgene on fly ash particles, and the aqueous separation of chlorination products. Results of an investigation of coal fly ash powder samples using photoacoustic infrared spectroscopy showed almost complete removal of adsorbed water after drying for 30 hours at 700/sup 0/C. A thermodynamic computer simulation of the chlorination of an SiO/sub 2/ and Al/sub 2/O/sub 3/ mixture of 2:1 molar ratio with a stoichiometric amount of carbon present revealed that silica is the preferred reactant at lower temperature, but that alumina chlorination is preferred at 800/sup 0/C. Experiments using phosgene to chlorinate acid-leached Texas lignite fly ash gave information about the kinetic rate dependence of the reaction involved. Work to determine the amount of chemisorption and physical adsorption of phosgene on pellets of the leached Texas lignite ash was initiated to permit the calculation of surface reaction rates. Separation of FeCl/sub 3/ by solvent extraction improved as the chloride ion concentration of the aqueous phase increased, regardless of whether the associated cation was hydrogen or aluminum. A static equilibrium cell/furnace arrangement with ultraviolet spectroscopy capability has been confirmed to be suitable for measurement of the absorbance of vapor species. A Harper 6 in. dia rotary kiln was used to continuously sinter a limestone-soda ash-fly ash mixture in the form of 1/8 in. dia pellets. Extraction of sintered material with dilute aqueous soda ash solution gave aluminate recoveries comparable to those obtained when small samples were sintered in a benchscale tube furnace. Results are presented which show that x-ray diffraction data can be used to calculate the amounts of individual compounds in sintered samples.

  4. Development of an ash particle deposition model considering build-up and removal mechanisms

    SciTech Connect

    Kjell Strandstroem; Christian Muellera; Mikko Hupa

    2007-12-15

    Slagging and fouling on heat exchanger surfaces in power boilers fired with fossil fuels and fuel mixtures has a significant influence on boiler efficiency and availability. Mathematical modelling has long been considered a suitable method to assist boiler operators to determine optimized operating conditions for an existing furnace. The ultimate goal in ash deposition prediction is hereby the determination of the total amount of material deposited and hence the determination of the total reduction in efficiency. Depending on the fuels fired the total deposited mass is a combination of ash particle deposition and ash particle erosion due to non-sticky particles. The novel ash particle deposition model presented in this work considers deposition of sticky ash particles, cleansing of deposit by non-sticky sand particles and sticking of sand due to contact with sticky ash. The steady-state modelling results for the total amount of ash deposited on the deposition probe of an entrained flow reactor presented in this work agree well with the experimental data. Only at very high fractions of sand added as non-sticky material, a significant influence of the sand on the overall mass deposited was found. Since the model considers sticking of non-sticking sand due to contact with sticky ash, the fraction of sand deposited on the probe was especially studied. Using a correction factor to consider the influence of operating time on the steady-state simulations led to good agreement between simulations and experimental data. 12 refs., 10 figs.

  5. Reuse potential of low-calcium bottom ash as aggregate through pelletization.

    PubMed

    Geetha, S; Ramamurthy, K

    2010-01-01

    Coal combustion residues which include fly ash, bottom ash and boiler slag is one of the major pollutants as these residues require large land area for their disposal. Among these residues, utilization of bottom ash in the construction industry is very low. This paper explains the use of bottom ash through pelletization. Raw bottom ash could not be pelletized as such due to its coarseness. Though pulverized bottom ash could be pelletized, the pelletization efficiency was low, and the aggregates were too weak to withstand the handling stresses. To improve the pelletization efficiency, different clay and cementitious binders were used with bottom ash. The influence of different factors and their interaction effects were studied on the duration of pelletization process and the pelletization efficiency through fractional factorial design. Addition of binders facilitated conversion of low-calcium bottom ash into aggregates. To achieve maximum pelletization efficiency, the binder content and moisture requirements vary with type of binder. Addition of Ca(OH)(2) improved the (i) pelletization efficiency, (ii) reduced the duration of pelletization process from an average of 14-7 min, and (iii) reduced the binder dosage for a given pelletization efficiency. For aggregate with clay binders and cementitious binder, Ca(OH)(2) and binder dosage have significant effect in reducing the duration of pelletization process. PMID:20400282

  6. Experimental Study on Ash-Returned Reactor of CFB Atmospheric Air Gasifier

    NASA Astrophysics Data System (ADS)

    Shihong, Zhang; Luning, Tian; Xianrong, Zhou; Hanping, Chen; Haiping, Yang; Xianhua, Wang

    In an attempt to improve the gasification efficiency and decrease the carbon content in fly ash of atmospheric air CFB gasifiers, an innovatory equipment by name ash-returned reactor is put forward by SKLCC. Ash-returned reactor is an ash-returned apparatus on line of ash circulation, typically like "U" type valve in CFB boilers, with additional function of some extent combustion of residual carbon and increase the furnace inlet temperature of returning ash, and hence the coal conversion of gasifiers is enhanced. As to its configuration compared to conventional "U" type valve, ash-returned rector has two distinguished features of several times of height scale of fluidizing transportation region to meet the combustion reaction time need and appropriate heat transfer tube bundles arranged in the region to moderate the local temperature so as to avoid slagging. And hence, corresponding to the structure renovation, the material transportation and regulation performance of ash-returned reactor is primarily investigated through a series of experiments in a cold lab-scale facility in this paper. The heat transfer characteristic of the tube bundles is then researched and its influential factors are further discussed. These works lay a foundation on the following study of hot state experiments and industrial applications.

  7. Reprocessing of metallurgical slag into materials for the building industry

    SciTech Connect

    Pioro, L.S.; Pioro, I.L

    2004-07-01

    Several methods of reprocessing metallurgical (blast furnace) slag into materials for the building industry, based on melting aggregates with submerged combustion, were developed and tested. The first method involves melting hot slag with some additives directly in a slag ladle with a submerged gas-air burner, with the objective of producing stabilized slag or glass-ceramic. The second method involves direct draining of melted slag from a ladle into the slag receiver, with subsequent control of the slag draining into the converter where special charging materials are added to the melt, with the objective of producing glass-ceramic. A third method involves melting cold slag with some additives inside a melting converter with submerged gas-air burners, with the objective of producing glass-ceramic fillers for use in road construction. Specific to the melting process is the use of a gas-air mixture with direct combustion inside the melt. This feature provides melt bubbling to help achieve maximum heat transfer from combustion products to the melt, improve mixing (and therefore homogeneity of the melt), and increases the rate of chemical reactions. The experimental data for different aspects of the proposed methods are presented. The reprocessed blast-furnace slag in the form of granules can be used as fillers for concretes, asphalts, and as additives in the production of cement, bricks and other building materials. As well, reprocessed blast-furnace slag can be poured into forms for the production of glass-ceramic tiles.

  8. Reprocessing of metallurgical slag into materials for the building industry.

    PubMed

    Pioro, L S; Pioro, I L

    2004-01-01

    Several methods of reprocessing metallurgical (blast furnace) slag into materials for the building industry, based on melting aggregates with submerged combustion, were developed and tested. The first method involves melting hot slag with some additives directly in a slag ladle with a submerged gas-air burner, with the objective of producing stabilized slag or glass-ceramic. The second method involves direct draining of melted slag from a ladle into the slag receiver, with subsequent control of the slag draining into the converter where special charging materials are added to the melt, with the objective of producing glass-ceramic. A third method involves melting cold slag with some additives inside a melting converter with submerged gas-air burners, with the objective of producing glass-ceramic fillers for use in road construction. Specific to the melting process is the use of a gas-air mixture with direct combustion inside the melt. This feature provides melt bubbling to help achieve maximum heat transfer from combustion products to the melt, improve mixing (and therefore homogeneity of the melt), and increases the rate of chemical reactions. The experimental data for different aspects of the proposed methods are presented. The reprocessed blast-furnace slag in the form of granules can be used as fillers for concretes, asphalts, and as additives in the production of cement, bricks and other building materials. As well, reprocessed blast-furnace slag can be poured into forms for the production of glass-ceramic tiles. PMID:15081065

  9. Dusting control of magnesium slag produced by Pidgeon process

    NASA Astrophysics Data System (ADS)

    Wu, Laner; Yang, Qixing; Han, Fenglan; Du, Chun

    2013-06-01

    Magnesium production by Pidgeon process has been developed very fast in China since 1990's. The waste slag from magnesium production has attracted broad attention because the huge amounts of the slag. For each ton of magnesium produced, there will be 6-8 tons of the slag generated. A big part of the Mg slag exists as fine dust with particle size of D95 < 0.1mm, which may pollute air, soil and water surrounding the Mg industry. The fine particles are generated by phase transformations of dicalcium silicate C2S (2CaOṡSiO2) during the slag cooling. There is a volume expansion of more than 10% with the transformation of β-C2S to γ-C2S phase, causing a disintegration or dusting of the Mg slag. In the present study, several chemical stabilizers were used to treat the dusting Mg slag at 1200°C, including borates, phosphates and rare earth oxides, in order to obtain volume stable slag aggregates for environmental protection and recycling of the Mg slag. The volume expanding rates of the samples were measured. XRD and SEM studies were carried out to confirm effects of the stabilizers. The results show that all of the stabilizers were effective for the stabilization of Mg slag. Some differences between the stabilizers were also described and discussed.

  10. Distribution of Bi Between Slags and Liquid Copper

    NASA Astrophysics Data System (ADS)

    Chen, Chunlin; Wright, Steven

    2016-06-01

    The distribution of Bi between liquid copper and calcium ferrite slag containing 24 wt pct CaO, iron silicate slag with 25 wt pct SiO2, and calcium iron silicate slags was measured at 1573 K (1300 °C) under controlled CO-CO2 atmosphere. The experimental results showed that bismuth distribution is affected by the oxygen partial pressure, and bismuth is likely to exist in slags in the 2+ oxidation state, i.e., as BiO. The distribution ratio between calcium ferrite slag and metal was found to be close to that of iron silicate slag. The Bi distribution ratio was found to decrease with increasing SiO2 and Al2O3 content in slag. Increasing temperature was found to decrease the Bi distribution ratio between slag and metal. Using the measured equilibrium data on Bi content of the metal and slag and composition dependence of the activity of Bi in liquid copper, the activity and hence activity coefficient of BiO in the slag was calculated. The close value of activity coefficient of BiO in both slags at the same oxygen partial pressure indicates that the CaO-BiO and SiO2-BiO interactions are likely to be at the same level, or the FeO x -BiO interaction is the predominant interaction for BiO in the slag. Therefore at a constant FeO x content in the slag, the CaO-BiO and SiO2-BiO interactions doesn't affect γ_{{BiO}} significantly.

  11. Synthesis and heavy metal immobilization behaviors of slag based geopolymer.

    PubMed

    Yunsheng, Zhang; Wei, Sun; Qianli, Chen; Lin, Chen

    2007-05-01

    In this paper, two aspects of studies are carried out: (1) synthesis of geopolymer by using slag and metakaolin; (2) immobilization behaviors of slag based geopolymer in a presence of Pb and Cu ions. As for the synthesis of slag based geopolymer, four different slag content (10%, 30%, 50%, 70%) and three types of curing regimes (standard curing, steam curing and autoclave curing) are investigated to obtain the optimum synthesis condition based on the compressive and flexural strength. The testing results showed that geopolymer mortar containing 50% slag that is synthesized at steam curing (80 degrees C for 8h), exhibits higher mechanical strengths. The compressive and flexural strengths of slag based geopolymer mortar are 75.2 MPa and 10.1 MPa, respectively. Additionally, Infrared (IR), X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques are used to characterize the microstructure of the slag based geopolymer paste. IR spectra show that the absorptive band at 1086 cm(-1) shifts to lower wave number around 1007 cm(-1), and some six-coordinated Als transforms into four-coordination during the synthesis of slag based geopolymer paste. The resulting slag based geopolymeric products are X-ray amorphous materials. SEM observation shows that it is possible to have geopolymeric gel and calcium silicate hydrate (C-S-H) gel forming simultaneously within slag based geopolymer paste. As for immobilization of heavy metals, the leaching tests are employed to investigate the immobilization behaviors of the slag based geopolymer mortar synthesized under the above optimum condition. The leaching tests show that slag based geopolymer mortar can effectively immobilize Cu and Pb heavy metal ions, and the immobilization efficiency reach 98.5% greater when heavy metals are incorporated in the slag geopolymeric matrix in the range of 0.1-0.3%. The Pb exhibits better immobilization efficiency than the Cu in the case of large dosages of heavy metals. PMID:17034943

  12. Long term contracts, expansion, innovation and stability: North Dakota's lignite mines thrive

    SciTech Connect

    Buchsbaum, L.

    2009-08-15

    North Dakota's lignite coal industry is mainly located in three countries in the central part of the state. Its large surface lignite mines are tied through long-term (20-40 years) contracts to power plants. The article talks about operations at three of the most productive mines - the Freedom mine, Falkirk mine and Center Mine. 4 figs.

  13. Evaluation of US coal performance in the shell coal gasification process (SCGP). Volume 1. Texas lignite. Final report

    SciTech Connect

    Heitz, W.L.; McCullough, G.R.; Gierman, H.; van Kessel, M.M.

    1984-02-01

    The Shell Coal Gasificaton Process was included in the EPRI evaluation of the more promising gasification technologies. This report evaluates the performance of Texas lignite in the SCGP. A companion report (RP2094-1) evaluates the performance of an Illinois No. 5 seam coal. Tests were conducted in the Shell Internationale Research Maatschappij B.V. Amsterdam laboratory process development unit (6 metric ton per day nominal throughput). Shell also has a 150 metric ton per day gasification process development unit at Deutsche Shell's Harburg Refinery, Federal Republic of Germany. These initial tests indicate that Texas lignite is as suitable for the Shell Coal Gasification Process as any bituminous coal previously tested and that only moderate conditions are required for gasification. Process variables included oxygen/MAF (moisture and ash free) coal ratios of 0.82 to 0.96 kg/kg, throughputs of 74 to 207 kg MAF coal/hr, and pressures of 2.1 to 2.8 MPa (1 MPa = 10 bar or 145 psia). Extensive environmental sampling programs were carried out with 50% of normal bleed water recycled to the process via an evaporating venturi. Carbon conversion was nearly complete (99+ %) at reactor outlet temperatures as low as 1250/sup 0/C; at a pressure of 2.1 MPa, a maximum thermal efficiency (76% of LHV-coal) was obtained at an oxygen/MAF coal ratio of 0.90 kg/kg. Process results were only marginally influenced by variations in coal throughput but an increase in pressure at constant throughput increased the cold gas efficiency by two percentage points to 78% of LHV coal (mainly through a reduction in heat loss). In a test on load-following characteristics of the process, the unit pressure remained constant and the flow of product gas responded within one minute to a stepwise change in coal feed rate.

  14. JV Task 90 - Activated Carbon Production from North Dakota Lignite

    SciTech Connect

    Steven Benson; Charlene Crocker; Rokan Zaman; Mark Musich; Edwin Olson

    2008-03-31

    The Energy & Environmental Research Center (EERC) has pursued a research program for producing activated carbon from North Dakota lignite that can be competitive with commercial-grade activated carbon. As part of this effort, small-scale production of activated carbon was produced from Fort Union lignite. A conceptual design of a commercial activated carbon production plant was drawn, and a market assessment was performed to determine likely revenue streams for the produced carbon. Activated carbon was produced from lignite coal in both laboratory-scale fixed-bed reactors and in a small pilot-scale rotary kiln. The EERC was successfully able to upgrade the laboratory-scale activated carbon production system to a pilot-scale rotary kiln system. The activated carbon produced from North Dakota lignite was superior to commercial grade DARCO{reg_sign} FGD and Rheinbraun's HOK activated coke product with respect to iodine number. The iodine number of North Dakota lignite-derived activated carbon was between 600 and 800 mg I{sub 2}/g, whereas the iodine number of DARCO FGD was between 500 and 600 mg I{sub 2}/g, and the iodine number of Rheinbraun's HOK activated coke product was around 275 mg I{sub 2}/g. The EERC performed both bench-scale and pilot-scale mercury capture tests using the activated carbon made under various optimization process conditions. For comparison, the mercury capture capability of commercial DARCO FGD was also tested. The lab-scale apparatus is a thin fixed-bed mercury-screening system, which has been used by the EERC for many mercury capture screen tests. The pilot-scale systems included two combustion units, both equipped with an electrostatic precipitator (ESP). Activated carbons were also tested in a slipstream baghouse at a Texas power plant. The results indicated that the activated carbon produced from North Dakota lignite coal is capable of removing mercury from flue gas. The tests showed that activated carbon with the greatest iodine number

  15. MHD generator performance comparisons between coal + ash firing. [Coal versus fuel oil with ashes added

    SciTech Connect

    Petty, S.; Enos, G.; Kessler, R.; Swallom, D.

    1983-08-01

    A two-stage slagging coal combustor developed by TRW Corporation, was successfully integrated with an MHD generator developed by the Avco Corporation, when the two companies cooperated in an operational demonstration of a coal fired MHD power train under the sponsorship of DOE. The experimental components, rated at a nominal 20 MW thermal input, are the engineering prototypes of 50 MW /SUB th/ hardware to be supplied by the contractors to the recently commissioned Component Development and Integration Facility (CDIF), a federal MHD test site in Butte, Montana. A second series of tests was conducted in which the same channel and operating parameters were employed with an oil-fired ash-injected combustor (AIC) to provide performance comparisons. The only significant performance variation uncovered in the comparison tests was attributable to a non-optimum method and location for seed injection in the coal-fired combustor. The corrective measures are deemed to be relatively straightforward.

  16. Chemistry of lignite liquefaction. Quarterly report, October-December 1981

    SciTech Connect

    Baltisberger, R.J.; Stenberg, V.I.; Klabunde, K.J.; Woolsey, N.F.

    1982-01-01

    Asphaltene and preasphaltene samples were isolated by solvent extraction using toluene and tetrahydrofuran, respectively, from GFETC liquefaction runs 44-14, 44-12, 45-15, 46-16 and 58-15. All the forty series samples were prepared from North Dakota lignite while 58-15 was from a Texas lignite. The quantity of preashpaltenes and asphaltenes in the five samples were 4.5 +- 0.5% wt and 13 +- 3% wt, respectively. The majority of the lignite was converted into distillable oils. The samples contain 7 to 10% wt oxygen for the preasphaltenes and 4 to 6% wt for the asphaltenes. The preasphaltene/asphaltene ratio of oxygen was 1.5 +- 0.1 for a given run. Approximately 50% of the oxygen is phenolic and the remainder we assume to be etheral types. In comparing process conditions, higher reaction pressures led to lower aromaticity and degree of condensation in the products, but had little effect on the oxygen content for the asphaltenes and raised the oxygen percentage for the preasphaltenes. Understanding the Catalytic Role of H/sub 2/S in Low-Rank Coal Liquefaction: One postulate on the mechanism of H/sub 2/S promotion of liquefaction is by means of its conversion into elemental sulfur in intermediate stages. Consequently, elemental sulfur was reacted with compounds postulated to approximate the crucial chemical bonds of coal which are necessary to rupture for liquefaction: diphenylmethane, bibenzyl, diphenyl ether and N,N-dimethylaniline. The reactions quickly proceeded at liquefaction temperatures to give a variety of products. A portion of these products are lower in molecular weight than the starting materials. Some of the products have been identified. N,N-dimethylaniline is demethylated with either elemental sulfur or H/sub 2/S sequentially via N-methylaniline.

  17. H-binding groups in lignite vs. soil humic acids: NICA-Donnan and spectroscopic parameters

    SciTech Connect

    Drosos, M.; Jerzykiewicz, M.; Deligiannakis, Y.

    2009-04-15

    A comparative study has been carried out for two sets of humic acids isolated from lignites and soils. H-binding data were analyzed using the NICA-Donnan model, for three Greek lignite humic acids (HA) plus IHSS Leonardite reference HA, and five Greek soil HAs plus a commercial peat HA. {sup 13}C-CP-MAS NMR and H-binding data provide quantitative estimates for functional groups, showing that lignite HAs of diverse origin have strikingly homogeneous properties, while the H-binding structural units of soil HAs are characterized by a large degree of variability. Consistent differences between soil HA vs. lignite HA are revealed at the level of functional groups' concentrations. In the pH range 4 to 10, soil HA showed a charge variation < 3 (equiv kg{sup -1}) while lignite HAs showed a higher charge variation > 3.5 (equiv kg{sup -1}).

  18. H-binding groups in lignite vs. soil humic acids: NICA-Donnan and spectroscopic parameters.

    PubMed

    Drosos, Marios; Jerzykiewicz, Maria; Deligiannakis, Yiannis

    2009-04-01

    A comparative study has been carried out for two sets of humic acids isolated from lignites and soils. H-binding data were analyzed using the NICA-Donnan model, for three Greek lignite humic acids (HA) plus IHSS Leonardite reference HA, and five Greek soil HAs plus a commercial peat HA. (13)C-CP-MAS NMR and H-binding data provide quantitative estimates for functional groups, showing that lignite HAs of diverse origin have strikingly homogeneous properties, while the H-binding structural units of soil HAs are characterized by a large degree of variability. Consistent differences between soil HA vs. lignite HA are revealed at the level of functional groups' concentrations. In the pH range 4 to 10, soil HA showed a charge variation <3 [equiv kg(-1)] while lignite HAs showed a higher charge variation >3.5 [equiv kg(-1)]. PMID:19144349

  19. Effect of Slag Basicity on Phase Equilibria and Selenium and Tellurium Distribution in Magnesia-Saturated Calcium Iron Silicate Slags

    NASA Astrophysics Data System (ADS)

    Johnston, M. D.; Jahanshahi, S.; Zhang, L.; Lincoln, F. J.

    2010-06-01

    New measurements have been made on the phase equilibria of magnesia-saturated CaO-FeOx-SiO2 slags at 1573 K (1300 °C) and an oxygen partial pressure of 10-9 atm. The thermodynamic behavior of selenium (Se) and tellurium (Te) in the slag and the stability of oxide mineral phases within the slag were examined as a function of slag composition. The measured equilibrium distribution of Se and Te between the slag and the copper showed nonlinear dependence on the slag basicity, reaching maxima at CaO/(CaO + SiO2) ratios of about 0.2 and 1 and a minimum at a ratio of about 0.5. The solubility of the copper oxide in the bulk slag also passed through a minimum value at a ratio of about 0.5. Results from drop-quench experiments confirmed the stability of various oxide solid solution phases at 1573 K (1300 °C) that had virtually no solubility for Se and Te. The deduced capacity of the liquid slag for Se was found to be independent of basicity in relatively basic slags, and decreased sharply as SiO2 replaced CaO in relatively acidic slags.

  20. Quantifying the Thermal Behavior of Slags (TRP 9903)

    SciTech Connect

    Alan W. Cramb

    2003-05-30

    Successful operation of a continuous caster is based upon control of heat transfer in the mold. The mold slag is a key component in the success of continuous casting; however, the phenomena that occur in the gap between the shell and the mold are largely unknown as until recently there have been no techniques that allowed visualization and quantification of the solidification behavior of liquid slags. This has lead to slag design being an empirical science or art. Recently a new experimental technique, called Double Hot Thermocouple Technique (DHTT), was developed at Carnegie Mellon University that allowed the solidification behavior of a slag to be observed and quantified under conditions that simulate the thermal conditions that occur in steelmaking environments. This technique allows ladle, tundish and mold slags to be characterized under extreme conditions including those found between the mold wall and the growing shell of a continuous caster. Thus, a program is initiated, under this grant, to quantify and describe the phenomena that occur during the solidification of a slag in a steel mill environment. This will allow slag design to become an engineering science rather than an empirical exercise. The project deliverables were as follows: (1) The further development of a tool that will have broad use in the quantification of slag melting and solidification behavior; and (2) The development of a set of meaningful design criteria for slag application in steel mill environments. The project was broken down into a number of objectives: (a) Develop a systematic understanding of the effect of cooling rate on slag solidification; (b) Develop a systematic understanding on the effect of slag chemistry changes on slag solidification behavior; (c) Develop a method to characterize slag melting; (d) Develop an understanding of the role of the environment on slag solidification and melting; (e) Develop the ability to understand slag solidification under the conditions that

  1. Oxydesulfurization of a Turkish hard lignite with ammonia solutions

    SciTech Connect

    Yaman, S.; Kuecuekbayrak, S.

    1996-09-01

    In this study the desulfurization of a high pyritic and high organic sulfur lignite taken from the Gediz area (western Turkey) was investigated by the oxydesulfurization method using ammonia solutions. The influence of such parameters as the concentration of ammonia solution, partial pressure of oxygen, temperature, and reaction time were studied. The ranges of these parameters were selected as 0--10 M concentration of ammonia solution, 0--1.5 MPa partial pressure of oxygen, 403--473 K temperature, and 10--60 min reaction time. It was concluded that the use of ammonia solution as an extraction solution increased the efficiency of the oxydesulfurization process.

  2. Reduction of quinquevalent vanadium solutions by wood and lignite

    USGS Publications Warehouse

    Pommer, A.M.

    1957-01-01

    To determine whether reduced vanadium ores could have been deposited by reduction from supergene quinquevalent vanadium solutions, the reducing capacity of fresh wood, wood degraded by long burial, and lignite was determined experimentally at temperatures of 120?? and 150?? in closed containers. A precipitate obtained by reduction of quinquevalent vanadium solutions with wood gave an X-ray pattern identical with a recently discovered low-valent vanadium mineral. The evidence indicated that deposition of reduced vanadium minerals by this mechanism is possible. ?? 1957.

  3. Levoglucosan and other cellulose and lignin markers in emissions from burning of Miocene lignites

    NASA Astrophysics Data System (ADS)

    Fabbri, Daniele; Torri, Cristian; Simoneit, Bernd R. T.; Marynowski, Leszek; Rushdi, Ahmed I.; Fabiańska, Monika J.

    Levoglucosan (L), mannosan (M), galactosan (G) and other cellulose and lignin markers from burn tests of Miocene lignites of Poland were determined by gas chromatography-mass spectrometry (GC-MS) to assess their distributions and concentrations in the smoke. Their distributions were compared to those in the pyrolysis products of the lignites. Levoglucosan and other anhydrosaccharides are products from the thermal degradation of cellulose and hemicellulose and are commonly used as tracers for wood smoke in the atmosphere. Here we report emission factors of levoglucosan in smoke particulate matter from burning of lignite varying from 713 to 2154 mg kg -1, which are similar to those from burning of extant plant biomass. Solvent extracts of the lignites revealed trace concentrations of native levoglucosan (0.52-3.7 mg kg -1), while pyrolysis yielded much higher levels (1.6-3.5 × 10 4 mg kg -1), indicating that essentially all levoglucosan in particulate matter of lignite smoke is derived from cellulose degradation. The results demonstrate that burning of lignites is an additional input of levoglucosan to the atmosphere in regions where brown coal is utilized as a domestic fuel. Interestingly, galactosan, another tracer from biomass burning, is not emitted in lignite smoke and mannosan is emitted at relatively low concentrations, ranging from 7.8 to 70.5 mg kg -1. Thus, we propose L/M and L/(M + G) ratios as discriminators between products from combustion of lignites and extant biomass. In addition, other compounds, such as shonanin, belonging to lignans, and some saccharides, e.g., α- and β-glucose and cellobiose, are reported for the first time in extracts of bulk lignites and of smoke particulate matter from burning these lignites.

  4. Selenium And Arsenic Speciation in Fly Ash From Full-Scale Coal-Burning Utility Plants

    SciTech Connect

    Huggins, F.E.; Senior, C.L.; Chu, P.; Ladwig, K.; Huffman, G.P.; /Kentucky U. /Reaction Engin. Int. /Elect. Power Res. Inst., Palo Alto

    2007-07-09

    X-ray absorption fine structure spectroscopy has been used to determine directly the oxidation states and speciation of selenium and arsenic in 10 fly ash samples collected from full-scale utility plants. Such information is needed to assess the health risk posed by these elements in fly ash and to understand their behavior during combustion and in fly ash disposal options, such as sequestration in tailings ponds. Selenium is found predominantly as Se(IV) in selenite (SeO{sub 3}{sup 2-}) species, whereas arsenic is found predominantly as As(V) in arsenate (AsO{sub 4}{sup 3-}) species. Two distinct types of selenite and arsenate spectra were observed depending upon whether the fly ash was derived from eastern U.S. bituminous (Fe-rich) coals or from western subbituminous or lignite (Ca-rich) coals. Similar spectral details were observed for both arsenic and selenium in the two different types of fly ash, suggesting that the post-combustion behavior and capture of both of these elements are likely controlled by the same dominant element or phase in each type of fly ash.

  5. The Effects of Orbital Distribution from Solid Rocket Motor Slag

    NASA Astrophysics Data System (ADS)

    Peng, Keke; Pang, Baojun; Xiao, Weike

    2013-08-01

    Solid rocket motor (SRM) firings are an important source of space debris environment. The resulting by-products are generally divided into two categories: slag and dust. Dust will re-entry sharply and do not pose a significant hazard. Slag debris can achieve centimeter level, these particles have a serious effect on risk assessment and defend structural design of spacecraft. It is important to understand the size distribution and orbital behavior of slag in order to predict the hazard posed both currently and in the future. Utilizing previous researches on SRM slag and 8-year launch cycle, we have analyzed the orbital distribution of SRM slag. The results indicate that SRM slag is a crucial component of the space debris environment. In order to sustainable utilization outer space, human should forbid the use of SRM in the future, especially for the medium Earth orbit (MEO) and geosynchronous Earth orbit (GEO) regions.

  6. PENETRATION OF COAL SLAGS INTO HIGH-CHROMIA REFRACTORIES

    SciTech Connect

    Longanbach, Sara C.; Matyas, Josef; Sundaram, S. K.

    2009-10-05

    Slagging coal gasifiers are used for the production of electricity and synthetic gases, as well as chemicals. High temperatures in the reaction chamber, typically between 1250ºC and 1600ºC, high pressure, generally greater than 400 psi, and corrosive slag place severe demands on the refractory materials. Slag produced during the combustion of coal flows over the refractory surface and penetrates the porous material. Slag penetration is typically followed by spalling of a brick that significantly decreases the service life of gasifier refractories. Laboratory tests were conducted to determine the penetration depth of slags into high-chromia refractories as a function of time and temperature for various refractory-slag combinations.

  7. The hydraulic potential of high iron bearing steel slags

    NASA Astrophysics Data System (ADS)

    Ionescu, Denisa Virginia

    The incorporation of additives to the clinker or to the raw materials stream is a common practice in cement manufacture. However, steel slag, unlike its ironmaking parent the blast furnace slag, it is not a conventional admixture for cement. Currently most steel slags are slow cooled rendering stable crystalline compounds with minor hydraulic value. Nevertheless, if steel slags would be quenched and granulated, the resulting glassy product might display increased hydration and strength development potential. The use of steel slag in cement could contribute to important savings for both cement and steelmaking industries and provide a solution for the environmental problems linked to CO2 emissions and costs of transport and disposal. The purpose of this research is to explore the thermodynamics and kinetics of steel slag hydration in an effort to produce a cement additive, or a more promising material of near Portland cement composition. An important criteria used in the assessment of slags as potential cements is the presence of a glassy phase. At present, it is not very clear why glass enhances the hydration process. However, it is known that the free energy of formation for glasses is less than for crystals so that glasses are easier to hydrate compared to crystalline materials. In the particular case of steel slag, the glassy phase would have to contain high amounts of iron. Steel slags are known to display iron levels approximately 10 times higher than Portland cement and commonly used blast furnace slags. However, the effect of high Fe2O3 levels on the setting and strengthening of cement paste is not clearly understood due to the fact that most cement additives do not present this characteristic. The present work looks at the progress made in recycling steel slag as cement additive, the complexity of the hydration process in slags, the possibilities of improving the hydration potential of slags at laboratory and industrial level, and the problems that still

  8. Evaluation of the distribution patterns of Pb, Cu and Cd from MSWI fly ash during thermal treatment by sequential extraction procedure.

    PubMed

    Chou, Jing-Dong; Wey, Ming-Yen; Chang, Shih-Hsien

    2009-03-15

    Municipal solid waste incinerator (MSWI) fly ash was frequently classified as hazardous materials as the metals' concentration of toxicity characteristic leaching procedure (TCLP) exceeded regulations. Many studies have focused on reducing the concentration of TCLP using thermal treatment and increasing the application of thermally treated slag. However, the metal patterns in MSWI fly ash with or without thermal treatment have seldom been addressed. The main objective of this study was evaluation of the distribution patterns of Pb, Cu and Cd from MSWI fly ash during thermal treatment by sequential extraction procedure. The experimental parameters included the form of pretreatment, the proportion of bottom ash (bottom ash/fly ash, B/F=0, 0.1 and 1) and the retention time. The results indicated that (1) In comparison to raw fly ash, the distribution patterns of Pb, Cu and Cd become stable in thermally treated slag. (2) Washing pretreatment caused the Pb pattern to become stable, while the influence on Cu and Cd were not significant. (3) The distribution patterns of Pb, Cu, and Cd became more stable as the retention time increased. (4) Adding bottom ash could make the distribution patterns of Pb and Cd more stable. PMID:18614278

  9. Fly-ash utilization

    SciTech Connect

    Lockerby, R.W.

    1984-01-01

    The over 200 references in this bibliography cover some of the uses found for fly-ash, which range from the manufacture of bricks and as a new type of concrete to the recovery of aluminum and other valuable ores from the ash. The entries are grouped under seven headings: General, Agriculture, Brickmaking, Cement/Concrete, Land Reclamation, Resource Recovery, and Other.

  10. The chemical composition of tertiary Indian coal ash and its combustion behaviour - a statistical approach: Part 2

    NASA Astrophysics Data System (ADS)

    Sharma, Arpita; Saikia, Ananya; Khare, Puja; Dutta, D. K.; Baruah, B. P.

    2014-08-01

    In Part 1 of the present investigation, 37 representative Eocene coal samples of Meghalaya, India were analyzed and their physico-chemical characteristics and the major oxides and minerals present in ash samples were studied for assessing the genesis of these coals. Various statistical tools were also applied to study their genesis. The datasets from Part 1 used in this investigation (Part 2) show the contribution of major oxides towards ash fusion temperatures (AFTs). The regression analysis of high temperature ash (HTA) composition and initial deformation temperature (IDT) show a definite increasing or decreasing trend, which has been used to determine the predictive indices for slagging, fouling, and abrasion propensities during combustion practices. The increase or decrease of IDT is influenced by the increase of Fe2O3, Al2O3, SiO2, and CaO, respectively. Detrital-authigenic index (DAI) calculated from the ash composition and its relation with AFT indicates Sialoferric nature of these coals. The correlation analysis, Principal Component Analysis (PCA), and Hierarchical Cluster Analysis (HCA) were used to study the possible fouling, slagging, and abrasion potentials in boilers during the coal combustion processes. A positive relationship between slagging and heating values of the coal has been found in this study.

  11. TRW Advanced Slagging Coal Combustor Utility Demonstration

    SciTech Connect

    Not Available

    1989-01-01

    The TRW Advanced Slagging Coal Combustor Demonstration Project consists of retrofitting Orange and Rockland (O R) Utility Corporation's Lovett Plant Unit No. 3 with four (4) slagging combustors which will allow the gas/ou desip unit to fire 2.5 sulfur coal. The slogging combustor process will provide NO[sub x] and SO[sub x] emissions that meet NSPS and New York State Envirommental Standards. TRW-CBU scope of work includes the engineering, design and supply of the slogging combustors, coal and limestone feed systems and a control system for these components. During this report period, the design activities for all systems progressed to permit the release of specifications and requests for proposals. Award of contracts for long-delivery items and major equipment are being placed to meet the revised program schedule.

  12. TRW advanced slagging coal combustor utility demonstration

    SciTech Connect

    Not Available

    1990-01-01

    The TRW Advanced Entrained Coal Combustor Demonstration Project consists of retrofitting Orange and Rockland (O R) Utility Corporation's Lovett Plant Unit No. 3 with four (4) slagging combustors which will allow the gas/oil unit to fire 2.5% sulfur coal. The slagging combustor process will provide NO{sub x} and SO{sub x} emissions that meet NSPS and New York State Environmental Standards. The TRW-Utility Demonstration Unit (UDU) is responsible for the implementation of program policies and overall direction of the project. The following projects will be carried out: process and design development of clean coal technology CCT-1 the development and operation of the entrained coal combustor will enable the boiler to burn low and medium sulfur coal while meeting all the Federal/State emission requirements; demonstrate sulfur dioxide emissions control by pulverized limestone injection into the entrained coal combustor system.

  13. Predictive thermochemistry and phase equilibria of slags

    NASA Astrophysics Data System (ADS)

    Barry, Thomas I.; Dinsdale, Alan T.; Gisby, John A.

    1993-04-01

    It is well understood that the efficient recovery of values by pyrometallurgical processing of ores requires control of the slag chemistry. In an effort to improve the understanding of slags, a thermodynamic database on subsystems of the CaO-MgO-Fe-O-Al2O3-SiO2 system has been generated through critical assessment of the literature. Data for connecting systems of specific industrial interest are being added. The data can be combined using well-established thermodynamic principles to make calculations on the multicomponent systems of practical interest. Following a description of the calculations, this article illustrates specific applications of thermodynamic modeling to the extraction of copper, nickel, and precious metals; zinc extraction; purification of pig iron; meltdown in nuclear reactors; hot corrosion; and pollution control.

  14. 40 CFR 424.30 - Applicability; description of the slag processing subcategory.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... values in the furnace slag are recovered via concentration for return to the furnace, or (b) the slag is... (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS FERROALLOY MANUFACTURING POINT SOURCE CATEGORY Slag...

  15. Reduction Kinetics of Electric Arc Furnace Oxidizing Slag by Al-Fe Alloy

    NASA Astrophysics Data System (ADS)

    Lee, Jaehong; Oh, Joon Seok; Lee, Joonho

    2016-07-01

    Effects of temperature and slag basicity on the reduction rate of iron oxide in molten synthetic electric arc furnace oxidizing slag by Al-40 wt.%Fe alloy was investigated. An alloy sample was dropped into molten slag in an MgO crucible. When the initial slag temperature was 1723 K, there was no reduction. However, when the initial slag temperature was 1773 K and the slag basicity was 1.1, the reduction was initiated and the temperature of the slag rapidly increased. When the slag basicity was 1.1, increasing the initial slag temperature from 1773 K to 1823 K increases the reaction rate. As the slag basicity increased from 1.1 to 1.4 at 1773 K, the reaction rate increased. From SEM analysis, it was found that an Al2O3 or a spinel phase at the slag-metal interface inhibited the reaction at a lower temperature and a lower slag basicity.

  16. Evaluation of steel furnace slags as cement additives

    SciTech Connect

    Tuefekci, M.; Demirbas, A.; Genc, H.

    1997-11-01

    Chemical and physical properties and strength development have been studied for six granulated steel furnace slags from the normal steelmaking process. This paper reports results of research performed to develop cement mixture proportions using these slags. The influence of slag proportions, specific surface, and water demand on compressive strength and bulk density of cement blends are presented in this paper. The different test results, which were compared with the Turkish Standards, in general, were found to be within the limits.

  17. Melting characteristics during the vitrification of MSWI fly ash with a pilot-scale diesel oil furnace.

    PubMed

    Wang, Qi; Tian, Shulei; Wang, Qunhui; Huang, Qifei; Yang, Jie

    2008-12-30

    Treatment of municipal solid waste incineration (MSWI) fly ash is becoming an important issue in China. A pilot-scale experiment was carried out to treat MSWI fly ash by using a diesel oil furnace (DOF) for more than 6 months. The effects of melting temperature on volume reduction, weight loss, compositional changes, and toxicity of leach water for molten slag have been investigated and reported. Results indicated that the volume reduction fraction of raw fly ash (RFA) and washed-fly ash (WFA) was 75-80% and the weight loss fraction was 23.8-30% at 1260-1350 degrees C. During the vitrification, CaO, A12O3, and SiO2 percentages in fly ash increased as the temperature increased, especially for SiO2, which was caused by both the decomposition of carbonates or sulfates and the volatilization of metal chlorides because the main components in secondary fly ash collected from fabric filter bags were NaCl and KCl. The leaching concentrations of heavy metals in molten slag were lower than the standard values of TCLP. The releasing levels of dioxin and other pollutants (such as SO2, HCl, CO, NOx, etc.) in flue gas were all lower than the Chinese standard. PMID:18439755

  18. Durability of Alkali Activated Blast Furnace Slag

    NASA Astrophysics Data System (ADS)

    Ellis, K.; Alharbi, N.; Matheu, P. S.; Varela, B.; Hailstone, R.

    2015-11-01

    The alkali activation of blast furnace slag has the potential to reduce the environmental impact of cementitious materials and to be applied in geographic zones where weather is a factor that negatively affects performance of materials based on Ordinary Portland Cement. The scientific literature provides many examples of alkali activated slag with high compressive strengths; however research into the durability and resistance to aggressive environments is still necessary for applications in harsh weather conditions. In this study two design mixes of blast furnace slag with mine tailings were activated with a potassium based solution. The design mixes were characterized by scanning electron microscopy, BET analysis and compressive strength testing. Freeze-thaw testing up to 100 freeze-thaw cycles was performed in 10% road salt solution. Our findings included compressive strength of up to 100 MPa after 28 days of curing and 120 MPa after freeze-thaw testing. The relationship between pore size, compressive strength, and compressive strength after freeze-thaw was explored.

  19. Windblown fugitive dust emissions from smelter slag

    NASA Astrophysics Data System (ADS)

    Sanderson, R. Steven; McKenna Neuman, Cheryl; Boulton, J. Wayne

    2014-06-01

    The waste products of mining and smelter operations contain fine particles that, when stored in stockpiles and tailings ponds, are subject to aerodynamic forces that may result in their suspension and transport within boundary layer air flows. The accuracy of atmospheric dispersion models such as AERMOD depends strongly upon suitable inputs for the emission rate that generally must be either measured or estimated from suitable analogues. Measurements of the emission rate of PM10 from smelter slag, based on wind tunnel experiments using the control volume method, are reported in this study and compared with vertical flux values obtained using a finite difference approximation. As compared to natural soils, the dust coatings on slag fragments are rapidly depleted during wind events so that the temporal aspect is important to capture in any consideration of the emission rate. At low wind speeds, vertical flux measurements underestimate the emission rate, but otherwise the agreement is excellent. Comparison with field measurements obtained at the smelter site reveals a degree of overlap with the laboratory data. As a general rule, PM10 emission from smelter slag by aerodynamic entrainment alone is several orders of magnitude lower than published fluxes of total suspended particulate (TSP) emitted from natural soil surfaces for which saltation bombardment is recognized to play a key role in the ejection of dust.

  20. Energy effective approach for activation of metallurgical slag

    NASA Astrophysics Data System (ADS)

    Mazov, I. N.; Khaydarov, B. B.; Mamulat, S. L.; Suvorov, D. S.; Saltikova, Y. S.; Yudin, A. G.; Kuznetsov, D. V.

    2016-01-01

    The paper presents results of investigation of the process of mechanical activation of metallurgical slag using different approaches - ball milling and electromagnetic vortex apparatus. Particle size distribution and structure of mechanically activated slag samples were investigated, as well as energetic parameters of the activation process. It was shown that electromagnetic vortex activation is more energy effective and allows to produce microscale milled slag-based concrete using very short treatment time. Activated slag materials can be used as clinker-free cement in civilian and road construction, providing ecology-friendly technology and recycling of high-tonnage industrial waste.

  1. Characteristics and environmental aspects of slag: a review

    USGS Publications Warehouse

    Piatak, Nadine M.; Parsons, Michael B.; Seal, Robert R., II

    2015-01-01

    The composition of ferrous slag is dominated by Ca and Si. Steel slag may contain significant Fe, whereas Mg and Al may be significant in Fe slag. Calcium-rich olivine-group silicates, melilite-group silicates that contain Al or Mg, Ca-rich glass, and oxides are the most commonly reported major phases in ferrous slag. Calcite and trace amounts of a variety of sulfides, intermetallic compounds, and pure metals are typically also present. The composition of non-ferrous slag, most commonly from base-metal production, is dominated by Fe and Si with significant but lesser amounts of Al and Ca. Silicates in the olivine, pyroxene, and melilite groups, as well as glass, spinels, and SiO2 (i.e., quartz and other polymorphs) are commonly found in non-ferrous slag. Sulfides and intermetallic compounds are less abundant than the silicates and oxides. The concentrations of some elements exceed generic USEPA soil screening levels for human contact based on multiple exposure pathways; these elements include Al, Cr, Cu, Fe, Mn, Pb, and Zn based on bulk chemical composition. Each slag type usually contains a specific suite of elements that may be of environmental concern. In general, non-ferrous slag may have a higher potential to negatively impact the environment compared to ferrous slag, and is thus a less attractive material for reuse, based on trace element chemistry, principally for base metals. However, the amount of elements released into the environment is not always consistent with bulk chemical composition. Many types of leaching tests have been used to help predict slag’s long-term environmental behavior. Overall, ferrous slags produce an alkaline leachate due to the dissolution of Ca oxides and silicates derived from compounds originally added as fluxing agents, such as lime. Ferrous slag leachate is commonly less metal-rich than leachate from non-ferrous slag generated during base metal extraction; the latter leachate may even be acidic due to the oxidation of

  2. Evaluation of copper slag blast media for railcar maintenance

    NASA Technical Reports Server (NTRS)

    Sagers, N. W.; Finlayson, Mack H.

    1989-01-01

    Copper slag was tested as a blasting substitute for zirconium silicate which is used to remove paint from railroad cars. The copper slag tested is less costly, strips paint faster, is produced near the point of need, provides a good bonding surface for paint, and permits the operator to work in a more comfortable position, i.e., standing nearly erect instead of having to crouch. Outdoor blasting with the tested Blackhawk (20 to 40 mesh) copper slag is also environmentally acceptable to the State of Utah. Results of tests for the surface erosion rate with copper slag blasting are included.

  3. Thermochemistry of calcium oxide and calcium hydroxide in fluoride slags

    NASA Astrophysics Data System (ADS)

    Chattopadhyay, S.; Mitchell, A.

    1990-08-01

    Calcium oxide activity in binary CaF2-CaO and ternary CaF2-CaO-Al2O3 and CaF2-CaO-SiO2 slags has been determined by CO2-slag equilibrium experiments at 1400 °C. The carbonate ca-pacity of these slags has also been computed and compared with sulfide capacity data available in the literature. The similarity in trends suggests the possibility of characterizing carbonate capacity as an alternative basicity index for fluoride-base slags. Slag-D2O equilibrium experi-ments are performed at 1400°C with different fluoride-base slags to determine water solubility at two different partial pressures of D2O, employing a new slag sampling technique. A novel isotope tracer detection technique is employed to analyze water in the slags. The water solubility data found show higher values than the previous literature data by an order of magnitude but show a linear relationship with the square root of water vapor partial pressure. The activity of hydroxide computed from the data is shown to be helpful in estimating water solubility in in-dustrial electroslag remelting (ESR) slags.

  4. The hydrogasification of lignite and sub-bituminous coals

    NASA Astrophysics Data System (ADS)

    Bhatt, B.; Fallon, P. T.; Steinberg, M.

    1981-02-01

    A North Dakota lignite and a New Mexico sub-bituminous coal have been hydrogenated at up to 900°C and 2500 psi hydrogen pressure. Yields of gaseous hydrocarbons and aromatic liquids have been studied as a function of temperature, pressure, residence time, feed rates and H2/coal ratio. Coal feed rates in excess of 10 lb/hr have been achieved in the 1 in. I. D.×8 ft reactor and methane concentration as high as 55% have been observed. A four-step reaction model was developed for the production and decomposition of the hydrocarbon products. A single object function formulated from the weighted errors for the four dependent process, variables, CH4, C2H6, BTX, and oil yields, was minimized using a program containing three independent iterative techniques. The results of the nonlinear regression analysis for lignite show that a first-order chemical reaction model with respect to C conversion satisfactorily describes the dilute phase hydrogenation. The activation energy for the initial products formation was estimated to be 42,700 cal/gmole and the power of hydrogen partial pressure was found to be +0.14. The overall correlation coefficient was 0.83. The mechanism, the rate expressions, and the design curves developed can be used for scale-up and reactor design.

  5. NO emission during oxy-fuel combustion of lignite

    SciTech Connect

    Andersson, K.; Normann, F.; Johnsson, F.; Leckner, B.

    2008-03-15

    This work presents experimental results and modeling of the combustion chemistry of the oxy-fuel (O{sub 2}/CO{sub 2} recycle) combustion process with a focus on the difference in NO formation between oxy-fired and air-fired conditions. Measurements were carried out in a 100 kW test unit, designed for oxy-fuel combustion with flue gas recycling. Gas concentration and temperature profiles in the furnace were measured during combustion of lignite. The tests comprise a reference test in air and three oxy-fuel cases with different oxygen fractions in the recycled feed gas. With the burner settings used, lignite oxy-combustion with a global oxygen fraction of 25 vol % in the feed gas results in flame temperatures close to those of air-firing. Similar to previous work, the NO emission (mg/MJ) during oxy-fuel operation is reduced to less than 30% of that of air-firing. Modeling shows that this reduction is caused by increased destruction of formed and recycled NO. The reverse Zeldovich mechanism was investigated by detailed modeling and was shown to significantly reduce NO at high temperature, given that the nitrogen content is low (low air leakage) and that the residence time is sufficient.

  6. Radiation intensity of lignite-fired oxy-fuel flames

    SciTech Connect

    Andersson, Klas; Johansson, Robert; Hjaertstam, Stefan; Johnsson, Filip; Leckner, Bo

    2008-10-15

    The radiative heat transfer in oxy-fuel flames is compared to corresponding conditions in air-fuel flames during combustion of lignite in the Chalmers 100 kW oxy-fuel test facility. In the oxy-fuel cases the flue-gas recycle rate was varied, so that, in principle, the same stoichiometry was kept in all cases, whereas the oxygen fraction in the recycled flue-gas mixture ranged from 25 to 29 vol.%. Radial profiles of gas concentration, temperature and total radiation intensity were measured in the furnace. The temperature, and thereby the total radiation intensity of the oxy-fuel flames, increases with decreasing flue-gas recycle rate. The ratio of gas and total radiation intensities increases under oxy-fuel conditions compared to air-firing. However, when radiation overlap between gas and particles is considered the ratios for air-firing and oxy-fuel conditions become more similar, since the gas-particle overlap is increased in the CO{sub 2}-rich atmosphere. A large fraction of the radiation in these lignite flames is emitted by particles whose radiation was not significantly influenced by oxy-fuel operation. Therefore, an increment of gas radiation due to higher CO{sub 2} concentration is not evident because of the background of particle radiation, and, the total radiation intensities are similar during oxy-fuel and air-fuel operation as long as the temperature distributions are similar. (author)

  7. Activated carbons from North Dakota lignite and leonardite

    SciTech Connect

    Young, B.C.; Olson, E.S.; Knudson, C.L.; Timpe, R.C.

    1995-12-01

    In a research and development program on carbon development, the EERC investigated key factors in the preparation of activated carbons from low-rank coals indigenous to North Dakota. The carbons were prepared for potential sorption applications with flue gas and waste liquid streams. Testing involved as-received, physically cleaned, and demineralized samples of a lignite and a leonardite. The following variables were examined: mineral matter content (7-19 wt%), carbonization temperature (350{degrees}-550{degrees}C), activation temperature (700{degrees}-1000{degrees}C), and activation time (10-60 minutes). Activated carbon samples were characterized by sorption of gaseous sulfur dioxide and liquid iodine. For both lignite and leonardite, sorption activity increased with lower mineral content and correlated with medium carbonization temperature and relatively high activation temperature but relatively short activation time. Steam activation did not significantly enhance the char`s sorptive capacity. Physically cleaned leonardite char had SO{sub 2} sorptive capacities as high as 10.9% of the sample weight at ambient temperatures.

  8. Activated carbons from North Dakota lignite and leonardite

    SciTech Connect

    Young, B.C.; Olson, E.S.; Knudson, C.L.; Timpe, R.C.

    1995-12-31

    The EERC is undertaking a research and development program on carbon development, part of which is directed towards investigating the key parameters in the preparation of activated carbons from low-rank coals indigenous to North Dakota. Carbons have been prepared and characterized for potential sorption applications in flue gas and waste liquid streams. Lignite, owing to its wide occurrence and variability in properties, has received significant attention as a precursor of active carbon manufacture. Mineral matter content and its alkaline nature are two highly variable properties that can have important consequences on the production of suitable activated carbons. Other factors affecting the production include carbonizing conditions, the activation agents, activation temperature, and activation time. However, as previously noted, the relationship between the above factors and the sorption activity is particularly complex. Part of the difficulty is that sorption activity encompasses at least three parameters, namely, surface area, pore distribution, and surface acidity/basicity. The presence of mineral matter in the coal can affect not only carbonization but also the activation and subsequent sorption and desorption processes. This paper presents results of an investigation of demineralization, carbonization temperature, activation temperature, and activation time for one lignite and leonardite from North Dakota.

  9. Utilizing acid mine drainage sludge and coal fly ash for phosphate removal from dairy wastewater.

    PubMed

    Wang, Y R; Tsang, Daniel C W; Olds, William E; Weber, Paul A

    2013-01-01

    This study aims to investigate a new and sustainable approach for the reuse of industrial by-products from wastewater treatment. The dairy industry produces huge volumes of wastewater, characterized by high levels of phosphate that can result in eutrophication and degradation of aquatic ecosystems. This study evaluated the application of acid mine drainage (AMD) sludge, coal fly ash, and lignite as low-cost adsorbents for the removal of phosphate from dairy wastewater. Material characterization using X-ray fluorescence, X-ray diffraction, and Brunauer-Emmett-Teller surface area analysis revealed significant amounts of crystalline/amorphous Fe/Al/Si/Ca-based minerals and large surface areas of AMD sludge and fly ash. Batch adsorption isotherms were best described using the Freundlich model. The Freundlich distribution coefficients were 13.7 mg(0.577) L(0.423) g(-1) and 16.9 mg(0.478) L(0.522) g(-1) for AMD sludge and fly ash, respectively, and the nonlinearity constants suggested favourable adsorption for column applications. The breakthrough curves of fixed-bed columns, containing greater than 10 wt% of the waste materials (individual or composite blends) mixed with sand, indicated that phosphate breakthrough did not occur within 100 pore volumes while the cumulative removal was 522 and 490 mg kg(-1) at 10 wt% AMD sludge and 10 wt% fly ash, respectively. By contrast, lignite exhibited negligible phosphate adsorption, possibly due to small amounts of inorganic minerals suitable for phosphate complexation and limited surface area. The results suggest that both AMD sludge and fly ash were potentially effective adsorbents if employed individually at a ratio of 10 wt% or above for column application. PMID:24617077

  10. Airborne crystalline silica concentrations at coal-fired power plants associated with coal fly ash.

    PubMed

    Hicks, Jeffrey; Yager, Janice

    2006-08-01

    This study presents measurements of airborne concentrations of respirable crystalline silica in the breathing zone of workers who were anticipated to encounter coal fly ash. Six plants were studied; two were fired with lignite coal, and the remaining four plants used bituminous and subbituminous coals. A total of 108 personal breathing zone respirable dust air samples were collected. Bulk samples were also collected from each plant site and subjected to crystalline silica analysis. Airborne dust particle size analysis was measured where fly ash was routinely encountered. The results from bituminous and subbituminous fired plants revealed that the highest airborne fly ash concentrations are encountered during maintenance activities: 0.008 mg/m3 to 96 mg/m3 (mean of 1.8 mg/m3). This group exceeded the threshold limit values (TLV) in 60% of the air samples. During normal production activities, airborne concentrations of crystalline silica ranged from nondetectable to 0.18 mg/m3 (mean value of 0.048 mg/m3). Air samples collected during these activities exceeded the current and proposed TLVs in approximately 54% and 65% of samples, respectively. Limited amounts of crystalline silica were detected in samples collected from lignite-fired plants, and approximately 20% of these air samples exceeded the current TLV. Particle size analysis in areas where breathing zone air samples were collected revealed mass median diameters typically between 3 microm and 8 microm. Bulk and air samples were analyzed for all of the common crystalline silica polymorphs, and only alpha quartz was detected. As compared with air samples, bulk samples from the same work areas consistently yielded lower relative amounts of quartz. Controls to limit coal fly ash exposures are indicated during some normal plant operations and during episodes of short term, but high concentrations of dust that may be encountered during maintenance activities, especially in areas where ash accumulations are present

  11. Field Trial Results of an Improved Refractory Material for Slagging Gasifiers

    SciTech Connect

    Bennett, J.P.; Kwong, K.-S.; Powell, C.P.; Petty, A.V., Jr.; Thomas, H.; Prior, H.D.; Schnake, M.

    2006-09-01

    Gasifiers are used commercially to react a carbon feedstock with water and oxygen under reducing conditions; producing chemicals used as feedstock for other processes, fuel for power plants, and/or steam used in other processes. A gasifier acts as a high temperature, high pressure reaction chamber, typically operating between 1250-1575°C, and with pressures between 300-1000 psi. Ash that originates from mineral impurities in the carbon feedstock becomes a by-product of gasification. In a slagging gasifier it melts, forming a liquid which flows down the gasifier sidewall; penetrating and wearing away the refractory liner by corrosive dissolution, abrasive wear, or by other processes such as spalling. The refractory liner must withstand the severe service environment, protecting the steel shell against corrosive gases, temperature, and material wear. Users have identified refractory service life as the most important limitation to sustained on-line availability of gasifiers, limiting gasifier acceptance and use by industry. The National Energy Technology Laboratory in Albany, OR, has developed and patented (US Patent # 6,815,386) a phosphate containing high chrome oxide refractory for use in slagging gasifiers. In cooperation with ANH Refractories Company, this refractory material has been commercially produced and is undergoing field tests in commercial gasifiers. An analysis of data from these field tests indicates that the phosphate containing refractory results in an improved service life over other refractory materials currently used as gasifier liners. Results from the post-mortem analysis of the field trial in relation to the failure mechanisms in a slagging gasifier will be presented.

  12. Appraisal of Hydrologic Information Needed in Anticipation of Lignite Mining in Lauderdale County, Tennessee

    USGS Publications Warehouse

    Parks, William Scott

    1981-01-01

    Lignite in western Tennessee occurs as lenses or beds at various stratigraphic horizons in the Coastal Plain sediments of Late Cretaceous and Tertiary age. The occurrence of this lignite has been known for many decades, but not until the energy crisis was it considered an important energy resource. In recent years, several energy companies have conducted extensive exploration programs in western Tennessee, and tremendous reserves of lignite have been found. From available information, Lauderdale County was selected as one of the counties where strip-mining of lignite will most likely occur. Lignite in this county occurs in the Jackson and Cockfield Formations, undivided, of Tertiary age. The hydrology of the county is known only from regional studies and the collection of some site-specific data. Therefore, in anticipation of the future mining of lignite, a plan is needed for obtaining hydrologic and geologic information to adequately define the hydrologic system before mining begins and to monitor the effects of strip-mining once it is begun. For this planning effort, available hydrologic, geologic, land use, and associated data were located and compiled; a summary description of the surface and shallow subsurface hydrologic system was prepared: the need for additional baseline hydrologic information was outlined; and plans to monitor the effects of strip-mining were proposed. This planning approach, although limited to a county area, has transferability to other Coastal Plain areas under consideration for strip-mining of lignite.

  13. Foamability of stainless steelmaking slags in an EAF

    NASA Astrophysics Data System (ADS)

    Kerr, James John

    Foaming in electric furnace steelmaking is desirable to allow for a longer arc and subsequently higher power operation in order to reduce the tap to tap time and consequently increase productivity. Stainless steelmaking slags do not foam as well as carbon steelmaking slags. To produce foam, the foamability or foam index of a slag and the gas generation rate must be adequate. The possible causes for the poor foamability of stainless steelmaking slags were examined in this research. Specifically the foam index of a simulated stainless steelmaking slag containing chrome oxide was measured and the rate at which carbon reacts with Cr2O3, CrO, and FeO was also measured. The experimental results show that the foam index of stainless steelmaking slags is comparable to carbon steelmaking slags provided that the amount of solid chrome oxide particles or complexes is not excessive. This indicates the low foamability is not due to a poor foam index. Gas is normally generated by cycling carbon into the slag, which produces CO by reducing oxides in the slag. The experimental results demonstrate that the reaction rate of carbon with CrO dissolved in the slag and hence the generation of CO is significantly slower than for the reaction rate of carbon with FeO dissolved in slags. Therefore, the lack of FeO or other reducible oxides in stainless steelmaking slags is a primary reason for the poor foamability. Experimental results indicate that limestone, nickel oxide, calcium nitrate, and waste oxide briquettes generate gas at sufficient rates to induce foaming when added to the stainless steelmaking slag. Heat transfer most likely controls the rate of CO2 generated by limestone and NiO reduction is controlled by mass transfer of NiO to the carbon in the slag. WOBs generate gas very rapidly due to intimate mixing of the carbon and iron oxides at unit activity. Calcium nitrate generates gas by dissociation and heat transfer likely controls the dissociation rate. Simple models are

  14. Petrological, geochemical and isotopic characteristics of lignite and calcified lignite from mining area Pesje, Velenje Basin, Slovenia

    NASA Astrophysics Data System (ADS)

    Vrabec, Mirijam; Markič, Miloš; Vrabec, Marko; Jaćimović, Radojko; Kanduč, Tjaša

    2014-05-01

    Lignite (organic rich) and calcified lignite (inorganic rich) samples from excavation field -50c mining area Pesje, Velenje Basin, Slovenia were investigated. During geological and structural mapping lignite and calcified lignite samples were systematically taken for determination of their petrological, geochemical and isotopic characteristics. Lignite is composed of fine detritical gelified matrix. At least five different types of calcified lignite were recognized forming laminations, calcifications after wood, petrified wood and complete replacements of lignite with carbonate. All measured parameters so far indicate geochemical processes during sedimentation of the Velenej Basin. After macroscopic description samples were split to organic and inorganic component (Ward, 1984) and powdered in an agate mortar for geochemical and isotopic analyses. Major and trace elements (As, B, Ba, Cd, Co, Cr, Cu, Hg, Mn, Mo, Sb, Se, Th, U, Zn) in these samples were determined by instrumental neutron activation analysis (INAA) using k-0 standardization method (Jaćimović et al, 2002). The isotopic composition of carbon and nitrogen was determined using a Europa 20-20 continuous flow IRMS ANCA-SL preparation module. A 1 mg amount of a sample was weighed in a tin capsule for carbon and 10 mg for nitrogen analysis. Samples for carbon analyses were pretreated with 1 M HCl to remove carbonates. Carbonate samples from carbonate-rich strata and calcified xylite were first roasted at 450 deg C (Krantz et al., 1987). Three miligrams of carbonate sample was transformed into CO2 by reaction with anhydrous H3PO4 at 55 deg C under vacuum (McCrea, 1950) and measured with GV 2003 isotope ratio mass spectrometer. Measured isotopic composition of oxygen as VPDB values was recalculated to the VSMOW reference standard to enable the comparison with data from other coal basins. SEM/EDXS of carbonate rich sediments was performed with JEOL JSM 5800 electron microanalyzer scanning electron microscope

  15. Coal ash monitors

    SciTech Connect

    Clayton, C.G.; Wormald, M.R.

    1981-07-14

    A monitor for determining the ash content of coal in rail cars consisting of a structure including means for irradiating each car as it passes the structure with a known dose of neutrons, means for detecting and measuring the intensities of gamma -rays emitted by ash-forming elements in the coal, and means for providing an indication of the concentration of the ash-forming elements. There also are included interlocks for ensuring that the neutron source is only operated when a loaded car is in the appropriate position.

  16. Chemical stabilization of chromate in blast furnace slag mixed cementitious materials.

    PubMed

    Meena, Amanda H; Kaplan, Daniel I; Powell, Brian A; Arai, Yuji

    2015-11-01

    Cement waste form (CWF) technology is among the leading approaches to disposing of metals and liquid low-level nuclear waste in the United States. One such material, saltstone, includes slag, fly ash and Portland cement to enhance the immobilization of contaminants (e.g., Cr, (99)Tc) in alkaline liquid wastes. To evaluate the stability of such redox sensitive contaminants in saltstone, the effects of slag as a source of reductant on Cr immobilization was evaluated in aged (<300 d) saltstone monoliths. Specifically, we investigated the effects of artificial cement pore waters on the Cr release and the spatially resolved Cr chemical state analysis using synchrotron based microfocused X-ray microprobe analysis. The microprobe analysis indicated the heterogeneous distribution of insoluble Cr(III)-species in saltstone. Although at most of 20% Crtotal was leached at the top few (2-3) millimeter depth, the release of Cr(VI) was small (<5%) at 5-30 mm with slight changes, indirectly suggesting that Cr is likely present as insoluble Cr(III) species throughout the depths. The study suggests that this saltstone formulation can effectively retain/immobilize Cr under the oxic field condition after ⩽300 d of aging time. PMID:26086810

  17. Analysis of char-slag interaction and near-wall particle segregation in entrained-flow gasification of coal

    SciTech Connect

    Montagnaro, Fabio; Salatino, Piero

    2010-05-15

    The fate of carbon particles during entrained-flow gasification of coal in the slagging regime is analyzed. More specifically, the study addresses the relevance of segregation of carbon particles in a near-wall region of the gasifier to coal conversion. Segregation of carbon particles is analyzed considering the effects of turbulence- and swirl-promoted particle migration toward the wall, interaction of the impinging particles with the wall ash layer, coverage of the slag layer by refractory carbon particles, accumulation of carbon particles in a dense-dispersed phase near the wall of the gasifier. Operating conditions of the gasifier and slag properties may be combined so as to give rise to a variety of conversion regimes characterized by distinctively different patterns of carbon particles segregation. A simple 1D model of an entrained-flow gasifier has been developed based on the conceptual framework of carbon particle segregation. The model aims at providing a general assessment of the impact of the different patterns of carbon particle segregation on the course and extent of carbon gasification. A sensitivity analysis with reference to selected model parameters is performed to identify key processes controlling carbon segregation and their impact on the gasifier performance. (author)

  18. Concentrations and source apportionment of PM10 and associated elemental and ionic species in a lignite-burning power generation area of southern Greece.

    PubMed

    Argyropoulos, G; Grigoratos, Th; Voutsinas, M; Samara, C

    2013-10-01

    Ambient concentrations of PM10 and associated elemental and ionic species were measured over the cold and the warm months of 2010 at an urban and two rural sites located in the lignite-fired power generation area of Megalopolis in Peloponnese, southern Greece. The PM10 concentrations at the urban site (44.2 ± 33.6 μg m(-3)) were significantly higher than those at the rural sites (23.7 ± 20.4 and 22.7 ± 26.9 μg m(-3)). Source apportionment of PM10 and associated components was accomplished by an advanced computational procedure, the robotic chemical mass balance model (RCMB), using chemical profiles for a variety of local fugitive dust sources (power plant fly ash, flue gas desulfurization wet ash, feeding lignite, infertile material from the opencast mines, paved and unpaved road dusts, soil), which were resuspended and sampled through a PM10 inlet onto filters and then chemically analyzed, as well as of other common sources such as vehicular traffic, residential oil combustion, biomass burning, uncontrolled waste burning, marine aerosol, and secondary aerosol formation. Geological dusts (road/soil dust) were found to be major PM10 contributors in both the cold and warm periods of the year, with average annual contribution of 32.6 % at the urban site vs. 22.0 and 29.0 % at the rural sites. Secondary aerosol also appeared to be a significant source, contributing 22.1 % at the urban site in comparison to 30.6 and 28.7 % at the rural sites. At all sites, the contribution of biomass burning was most significant in winter (28.2 % at the urban site vs. 14.6 and 24.6 % at the rural sites), whereas vehicular exhaust contribution appeared to be important mostly in the summer (21.9 % at the urban site vs. 11.5 and 10.5 % at the rural sites). The highest contribution of fly ash (33.2 %) was found at the rural site located to the north of the power plants during wintertime, when winds are favorable. In the warm period, the highest contribution of fly ash was found at the

  19. Bioprocessing of lignite coals using reductive microorganisms. Final technical report, September 30, 1988--March 29, 1992

    SciTech Connect

    Crawford, D.L.

    1992-03-29

    In order to convert lignite coals into liquid fuels, gases or chemical feedstock, the macromolecular structure of the coal must be broken down into low molecular weight fractions prior to further modification. Our research focused on this aspect of coal bioprocessing. We isolated, characterized and studied the lignite coal-depolymerizing organisms Streptomyces viridosporus T7A, Pseudomonas sp. DLC-62, unidentified bacterial strain DLC-BB2 and Gram-positive Bacillus megaterium strain DLC-21. In this research we showed that these bacteria are able to solubilize and depolymerize lignite coals using a combination of biological mechanisms including the excretion of coal solublizing basic chemical metabolites and extracellular coal depolymerizing enzymes.

  20. Quantitative evaluation of minerals in fly ashes of biomass, coal and biomass-coal mixture derived from circulating fluidised bed combustion technology.

    PubMed

    Koukouzas, Nikolaos; Ward, Colin R; Papanikolaou, Dimitra; Li, Zhongsheng; Ketikidis, Chrisovalantis

    2009-09-30

    The chemical and mineralogical composition of fly ash samples collected from laboratory scale circulating fluidised bed (CFB) combustion facility have been investigated. Three fly ashes were collected from the second cyclone in a 50 kW laboratory scale boiler, after the combustion of different solid fuels. Characterisation of the fly ash samples was conducted by means of X-ray fluorescence (XRF), X-ray diffraction (XRD) and scanning electron microscopy (SEM). Quantitative analysis of the crystalline (mineral) and amorphous phases in each ash sample was carried out using the Rietveld-based Siroquant system, with an added spike of ZnO to evaluate the amorphous content. SiO(2) is the dominant oxide in the fly ashes, with CaO, Al(2)O(3) and Fe(2)O(3) also present in significant proportions. XRD results show that all three fly ashes contain quartz, anhydrite, hematite, illite and amorphous phases. The minerals calcite, feldspar, lime and periclase are present in ashes derived from Polish coal and/or woodchips. Ash from FBC combustion of a Greek lignite contains abundant illite, whereas illite is present only in minor proportions in the other ash samples. PMID:19410365

  1. A General Viscosity Model for Molten Blast Furnace Slag

    NASA Astrophysics Data System (ADS)

    Gan, Lei; Lai, Chaobin

    2014-06-01

    Blast furnace slag is the most abundant slag in the steel industry. Its metallurgical properties are determined to a great extent by its viscosity. Therefore, it is necessary to establish a reliable viscosity model for blast furnace slag. In the current work, a simple, accurate, and physically meaningful viscosity model for a wide composition range of blast furnace slags is developed based on the Vogel-Fulcher-Tammann (VFT) equation: log η = A + B/( T - C). The model is calibrated by a database containing 365 compositions and 1233 measurements of synthetic and industrial slags. The parameter A has a value of -3.10. The parameters B and C are related to the mass fraction ratio of (CaO + MgO) to (SiO2 + Al2O3) and liquidus temperature of the slag, respectively. Present viscosity model accurately predicts the viscosity of blast furnace slag with relative average error (Δ) of 0.211 (±0.180) and root mean square error (RMSE) of 0.239 Pa·s. A slight modification of this model can also predict the glass transition temperature of blast furnace slag satisfactorily.

  2. Modeling of Manganese Ferroalloy Slag Properties and Flow During Tapping

    NASA Astrophysics Data System (ADS)

    Muller, Jacques; Zietsman, Johannes Hendrik; Pistorius, Petrus Christiaan

    2015-12-01

    Stable operation of submerged-arc furnaces producing high-carbon ferromanganese (HCFeMn) and silicomanganese (SiMn) requires tapping of consistent amounts of liquid slag and metal. Minimal effort to initiate and sustain tapping at reasonable rates is desired, accommodating fluctuations in especially slag chemical composition and temperature. An analytical model is presented that estimates the tapping rate of the liquid slag-metal mixture as a function of taphole dimensions, coke bed particulate properties, and slag and metal physicochemical properties with dependencies on chemical composition and temperature. This model may be used to evaluate the sensitivity to fluctuations in these parameters, and to determine the influence of converting between HCFeMn and SiMn production. The model was applied to typical HCFeMn and SiMn process conditions, using modeled slag viscosities and densities. Tapping flow rates estimated were comparable to operational data and found to be dependent mostly on slag viscosity. Slag viscosities were generally lower for typical SiMn slags due to the higher temperature used for calculating viscosity. It was predicted that flow through the taphole would mostly develop into laminar flow, with the pressure drop predominantly over the coke bed. Flow rates were found to be more dependent on the taphole diameter than on the taphole length.

  3. Micronutrient availability from steel slag amendment in pine bark substrates

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Steel slag is a byproduct of the steel industry that can be used as a liming agent, but also has a high mineral nutrient content. While micronutrients are present in steel slag, it is not known if the mineral form of the micronutrients would render them available for plant uptake. The objective of...

  4. A ceramographic evaluation of chromia refractories corroded by slag

    SciTech Connect

    Hunt, Alton H.; Chinn, Richard E.

    2001-01-01

    This paper describes the ceramographic preparation of Cr{sub 2}O{sub 3}-Al{sub 2}O{sub 3} refractory bricks and subsequent microstructural analysis to determine the corrosive effects of molten slag. The porous and friable nature of the brick, especially after exposure to the slag or its individual components, presented some problems in the preparation.

  5. Modeling of Time Varying Slag Flow in Coal Gasifiers

    SciTech Connect

    Pilli, Siva Prasad; Johnson, Kenneth I.; Williford, Ralph E.; Sundaram, S. K.; Korolev, Vladimir N.; Crum, Jarrod V.

    2008-08-30

    There is considerable interest within government agencies and the energy industries across the globe to further advance the clean and economical conversion of coal into liquid fuels to reduce our dependency on imported oil. To date, advances in these areas have been largely based on experimental work. Although there are some detailed systems level performance models, little work has been done on numerical modeling of the component level processes. If accurate models are developed, then significant R&D time might be saved, new insights into the process might be gained, and some good predictions of process or performance can be made. One such area is the characterization of slag deposition and flow on the gasifier walls. Understanding slag rheology and slag-refractory interactions is critical to design and operation of gasifiers with extended refractory lifetimes and also to better control of operating parameters so that the overall gasifier performance with extended service life can be optimized. In the present work, the literature on slag flow modeling was reviewed and a model similar to Seggiani’s was developed to simulate the time varying slag accumulation and flow on the walls of a Prenflo coal gasifier. This model was further extended and modified to simulate a refractory wall gasifier including heat transfer through the refractory wall with flowing slag in contact with the refractory. The model was used to simulate temperature dependent slag flow using rheology data from our experimental slag testing program. These modeling results as well as experimental validation are presented.

  6. 15. TAKING A CAST AT FURNACE NO. 1 HOT SLAG, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    15. TAKING A CAST AT FURNACE NO. 1 HOT SLAG, BY-PRODUCT IN SMELTING OF PIG IRON, CAN BE SEEN FLOWING INTO THE SLAG YARD. VIEW IS LOOKING SOUTH. - Corrigan, McKinney Steel Company, 3100 East Forty-fifth Street, Cleveland, Cuyahoga County, OH

  7. INTERIOR VIEW WITH SKIMMER, BRUCE ELLIOTT, RAKING SLAG FROM THE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    INTERIOR VIEW WITH SKIMMER, BRUCE ELLIOTT, RAKING SLAG FROM THE LADLE OF MOLTEN METAL. THE MOLTEN SLAG SPARKS AS IT HITS THE MIXER BUILDING FLOOR. - American Cast Iron Pipe Company, Mixer Building, 1501 Thirty-first Avenue North, Birmingham, Jefferson County, AL

  8. Ash cloud aviation advisories

    SciTech Connect

    Sullivan, T.J.; Ellis, J.S.; Schalk, W.W.; Nasstrom, J.S.

    1992-06-25

    During the recent (12--22 June 1991) Mount Pinatubo volcano eruptions, the US Air Force Global Weather Central (AFGWC) requested assistance of the US Department of Energy`s Atmospheric Release Advisory Capability (ARAC) in creating volcanic ash cloud aviation advisories for the region of the Philippine Islands. Through application of its three-dimensional material transport and diffusion models using AFGWC meteorological analysis and forecast wind fields ARAC developed extensive analysis and 12-hourly forecast ash cloud position advisories extending to 48 hours for a period of five days. The advisories consisted of ``relative`` ash cloud concentrations in ten layers (surface-5,000 feet, 5,000--10,000 feet and every 10,000 feet to 90,000 feet). The ash was represented as a log-normal size distribution of 10--200 {mu}m diameter solid particles. Size-dependent ``ashfall`` was simulated over time as the eruption clouds dispersed. Except for an internal experimental attempt to model one of the Mount Redoubt, Alaska, eruptions (12/89), ARAC had no prior experience in modeling volcanic eruption ash hazards. For the cataclysmic eruption of 15--16 June, the complex three-dimensional atmospheric structure of the region produced dramatically divergent ash cloud patterns. The large eruptions (> 7--10 km) produced ash plume clouds with strong westward transport over the South China Sea, Southeast Asia, India and beyond. The low-level eruptions (< 7 km) and quasi-steady-state venting produced a plume which generally dispersed to the north and east throughout the support period. Modeling the sequence of eruptions presented a unique challenge. Although the initial approach proved viable, further refinement is necessary and possible. A distinct need exists to quantify eruptions consistently such that ``relative`` ash concentrations relate to specific aviation hazard categories.

  9. Experimental Study of Hydrogasification of Lignite and Subbituminous Coal Chars

    PubMed Central

    Gil, Stanisław

    2015-01-01

    The experimental facility for pressure hydrogasification research was adapted to the pressure of 10 MPa and temperature of 1300 K, which ensured repeatability of results and hydrogen heating to the process temperature. A hydrogasification reaction of chars produced from two rank coals was investigated at temperatures up to 1173 K, pressures up to 8 MPa, and the gas flow rates of 0.5–5 dmn3/min. Reactivity of the “Szczerców” lignite char was found to be slightly higher than that of the subbituminous “Janina” coal char produced under the same conditions. A high value of the char reactivity was observed to a certain carbon conversion degree, above which a sharp drop took place. It was shown that, to achieve proper carbon conversion, the hydrogasification reaction must proceed at a temperature above 1200 K. PMID:26065028

  10. Discrimination of unique biological communities in the Mississippi lignite belt

    NASA Technical Reports Server (NTRS)

    Miller, W. F. (Principal Investigator); Cutler, J. D.

    1981-01-01

    Small scale hardcopy LANDSAT prints were manually interpreted and color infrared aerial photography was obtained in an effort to identify and map large contiguous areas of old growth hardwood stands within Mississippi's lignite belt which do not exhibit signs of recent disturbance by agriculture, grazing, timber harvesting, fire, or any natural catastrophe, and which may, therefore, contain unique or historical ecological habitat types. An information system using land cover classes derived from digital LANDSAT data and containing information on geology, hydrology, soils, and cultural activities was developed. Using computer-assisted land cover classifications, all hardwood remnants in the study area which are subject to possible disturbance from surface mining were determined. Twelve rare plants were also identified by botanists.

  11. Progress in Slag Foaming in Metallurgical Processes

    NASA Astrophysics Data System (ADS)

    Zhu, Tai Xi; Coley, K. S.; Irons, G. A.

    2012-08-01

    Professor Fruehan has been a pioneer in the fundamental understanding of slag foaming in ironmaking and steelmaking processes. Although considerable progress has been made in our understanding of the phenomena, there are still unanswered questions regarding the mechanisms in industrial processes and how to control them. At McMaster University, we have been working on conditions that are relevant to foaming in electric arc furnaces (EAFs) where these phenomena are central to modern EAF practices. This work will be reviewed and put in the context of what is known from a fundamental standpoint.

  12. Microbial screening test for lignite degradation: Quarterly progress report No. 9 for the period January-March 1987

    SciTech Connect

    Yen, Teh Fu

    1987-03-01

    Anaerobic fermentation of water soluble fraction of modified lignite was attempted. Solubilized lignite formed bioprecipitate after biodegradation. Fermentation of water solubilized lignite in enrichment media produced gases and organic acids. FT-IR spectra of solubilized lignite after biodegradation showed that the concentration of organic oxygen have decreased and that the concentration of -CH/sub 3/ terminal group have increased. Solubilized lignite may serve as sole carbon source by using selective media. Bacteria was suspected of being able to utilize fulvic-like materials from solubilized lignite. Isolation of anaerobic bacteria was achieved by surface culture, and it indicated morphological differences among isolated colonies. Alginate gel entrapment, an immobilization method, was applied to T. versicolor fungal cells. Active fungal growth was observed from the immobilized spheres on sodium-alginate gel. It seems that the immobilized biocatalysts may be used to enhance the production of bioextract from lignite in a reactor system. Hydroxylation of lignite was accomplished through Fenton reaction at pH 7.5. FT-IR analysis showed that lignite treated with Fenton's reagent exhibits weaker aromatic bending and ether linkage than untreated lignite. 13 refs., 8 figs.

  13. Solidification of stainless steel slag by accelerated carbonation.

    PubMed

    Johnson, D C; MacLeod, C L; Carey, P J; Hills, C D

    2003-06-01

    On exposure to carbon dioxide (CO2) at a pressure of 3 bars, compacts formed from pressed ground slag, and 12.5 weight percent water, were found to react with approximately 18% of their own weight of CO2. The reaction product formed was calcium carbonate causing the slag to self-cement. Unconfined compressive strengths of 9MPa were recorded in carbonated compacts whereas strengths of < 1 MPa were recorded in non-carbonated slag compacts. As molten stainless steel slag containing dicalcium silicate (C2S) cools it can undergo several phase transitions. The final transformation from the beta-polymorph to gamma-C2S is accompanied by a volume change that causes the slag to self-pulverise or 'dust'. As a consequence of this the fine grained portion of the slag contains more of this phase whilst the coarser particles of the slag contain more of the calcium magnesium silicates that contribute the bulk of the waste. The fine fraction (< 125 microm) of the slag when ground is found to react to the same extent as the ground bulk slag and produces compacts with equivalent strength. A coarser fraction (4-8 mm) when ground to a similar grading does not react as extensively and produces a weaker product. Additions of ordinary Portland cement (OPC) at 5 and 10 percent by weight did not alter the degree of reaction during carbonation of the bulk slag or ground fine fraction, however the strength of the 4-8 mm fraction was increased by this change. PMID:12868521

  14. Review of lignite resources of western Tennessee and the Jackson Purchase area, western Kentucky

    USGS Publications Warehouse

    Hackley, Paul C.; Warwick, Peter D.; Thomas, Roger E.; Nichols, Douglas J.

    2006-01-01

    Introduction: This review of the lignite deposits of western Tennessee and the Jackson Purchase area in western Kentucky (Fig. 1) is a preliminary report on part of the U.S. Geological Survey's National Coal Resource Assessment of the Gulf Coastal Plain Coal Province. Lignite deposits of western Kentucky and Tennessee are an extension of the Gulf Coastal Plain Coal Province (Cushing and others, 1964), and currently are not economic to mine. These deposits have not been extensively investigated or developed as an energy resource. This review includes a description of the geology of the lignite-bearing units, a discussion of the available coal quality data, and information on organic petrology. Palynological data for lignite samples collected in Kentucky and Tennessee as part of this work are presented in an Appendix.

  15. Nonisothermal Thermogravimetric Analysis of Thai Lignite with High CaO Content

    PubMed Central

    Pintana, Pakamon

    2013-01-01

    Thermal behaviors and combustion kinetics of Thai lignite with different SO3-free CaO contents were investigated. Nonisothermal thermogravimetric method was carried out under oxygen environment at heating rates of 10, 30, and 50°C min−1 from ambient up to 1300°C. Flynn-Wall-Ozawa (FWO) and Kissinger-Akahira-Sunose (KAS) methods were adopted to estimate the apparent activation energy (E) for the thermal decomposition of these coals. Different thermal degradation behaviors were observed in lignites with low (14%) and high (42%) CaO content. Activation energy of the lignite combustion was found to vary with the conversion fraction. In comparison with the KAS method, higher E values were obtained by the FWO method for all conversions considered. High CaO lignite was observed to have higher activation energy than the low CaO coal. PMID:24250259

  16. Rank and petrology of the Middle Miocene Karapinar lignites in southeast Turkey

    SciTech Connect

    Karayigit, A.I.; Goodarzi, F.; Ardag, Y.; Gentzis, T.

    1996-12-01

    The coal-bearing strata in the Basoren Formation from the Sariz-Karapinar coal region are of middle Miocene age and were deposited in a lacustrine environment. Coal in this formation is lignitic in rank (%Ro, random of eu-ulminite B is 0.37). These lignites have high inertinite content (up to 37.4%), which is higher than in any other Turkish lignites studied previously. Inertinite content in the region increases from the northeast to the southwest, possibly indicating oxidation of organic matter in the coal-forming environment due to lowering of the water level. Total sulfur content in the lignites ranges from 1.8 to 4.8%. High-rank coals present in the Upper Permian Yigiltepe Formation (%Ro, random is 0.66--0.70) contain more sulfur (S{sub tot} = 5.6--6.9%) and less inertinite (9.6--12.1%).

  17. 30 CFR 75.1319 - Weight of explosives permitted in boreholes in bituminous and lignite mines.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... and Blasting § 75.1319 Weight of explosives permitted in boreholes in bituminous and lignite mines. (a... 3 pounds except when blasting solid rock in its natural deposit. (b) The total weight of...

  18. Biomass fuel leaching for the control of fouling, slagging, and agglomeration in biomass power generation

    NASA Astrophysics Data System (ADS)

    Bakker, Robert Reurd

    The use of straws and other herbaceous biomass as boiler fuel is limited because of rapid formation of boiler deposits (i.e. fouling and slagging), which results in high boiler operating costs. The removal of troublesome elements in biomass that lead to slagging and fouling was tested by washing (leaching) biomass fuels in water. Potassium, sodium, and chlorine are easily removed from rice straw and other biomass in both tap and distilled water. Simple water leaching leads to considerable changes in combustion properties and ash transformation in biomass. In general, leaching elevates the sintering and melting temperatures, improves ash fusibility, and reduces the volatilization of inorganic species. Leaching leads to a notable decline in the alkali index, a broad indicator of the fouling potential of a biomass fuel. Bench-scale combustion tests at 800-1000°C furnace gas temperatures confirm that leaching dramatically changes the combustion behavior of rice straw. Full-scale combustion tests indicate that leached rice straw is technically suitable under normal boiler operating conditions. Two potential strategies to accomplish leaching of rice straw include leaching under controlled circumstances, and leaching by natural precipitation. Under controlled conditions, substantial amounts of K and Cl can be leached from rice straw with water at ambient temperatures, and without extensive particle size reduction. Leaching straw in a full-scale process is estimated to add approximately $15 to 18 Mg-1 to the fuel costs of a combustion facility. Leaving rice straw in the field and exposed to rainy weather leads to similar improvements in combustion behavior as observed with biomass that is leached under controlled circumstances. Collection of naturally leached rice straw in the Sacramento Valley through delayed harvesting is technically feasible, however its commercial implementation is dependent on harvest practices, rainfall distribution, and field-specific factors. The

  19. Industrial Application Study on New-Type Mixed-Flow Fluidized Bed Bottom Ash Cooler

    NASA Astrophysics Data System (ADS)

    Zeng, B.; Lu, X. F.; Liu, H. Z.

    As a key auxiliary device of CFB boiler, the bottom ash cooler (BAC) has a direct influence on secure and economic operation of the boiler. The operating situation of domestic CFB power plant is complex and changeable with a bad coal-fired condition. The principle for designing BAC suitable for the bad coal-fired condition and high parameter CFB boilers was summarized in this paper. Meanwhile, a new-type mixed-flow fluidized bed bottom ash cooler was successfully designed on the basis of the comprehensive investigation on the existing BAC s merits and drawbacks. Using coarse/fine slag separation technology and micro-bubbling fluidization are the significant characteristics of this new BAC. This paper also puts great emphasis on its industrial test in a 460t/h CFB boiler. The results indicate that it achieves significant separation of the coarse/fine slag, an obvious cooling effect, no slag block and coking phenomenon, and continuous stable operation. Figs 7, Tabs 4 and Refs 11.

  20. Effects of lignite application on ammonia and nitrous oxide emissions from cattle pens.

    PubMed

    Sun, Jianlei; Bai, Mei; Shen, Jianlin; Griffith, David W T; Denmead, Owen T; Hill, Julian; Lam, Shu Kee; Mosier, Arvin R; Chen, Deli

    2016-09-15

    Beef cattle feedlots are a major source of ammonia (NH3) emissions from livestock industries. We investigated the effects of lignite surface applications on NH3 and nitrous oxide (N2O) emissions from beef cattle feedlot pens. Two rates of lignite, 3 and 6kgm(-2), were tested in the treatment pen. No lignite was applied in the control pen. Twenty-four Black Angus steers were fed identical commercial rations in each pen. We measured NH3 and N2O concentrations continuously from 4th Sep to 13th Nov 2014 using Quantum Cascade Laser (QCL) NH3 analysers and a closed-path Fourier Transform Infrared Spectroscopy analyser (CP-FTIR) in conjunction with the integrated horizontal flux method to calculate NH3 and N2O fluxes. During the feeding period, 16 and 26% of the excreted nitrogen (N) (240gNhead(-1)day(-1)) was lost via NH3 volatilization from the control pen, while lignite application decreased NH3 volatilization to 12 and 18% of the excreted N, for Phase 1 and Phase 2, respectively. Compared to the control pen, lignite application decreased NH3 emissions by approximately 30%. Nitrous oxide emissions from the cattle pens were small, 0.10 and 0.14gN2O-Nhead(-1)day(-1) (<0.1% of excreted N) for the control pen, for Phase 1 and Phase 2, respectively. Lignite application increased direct N2O emissions by 40 and 57%, to 0.14 and 0.22gN2O-Nhead(-1)day(-1), for Phase 1 and Phase 2, respectively. The increase in N2O emissions resulting from lignite application was counteracted by the lower indirect N2O emission due to decreased NH3 volatilization. Using 1% as a default emission factor of deposited NH3 for indirect N2O emissions, the application of lignite decreased total N2O emissions. PMID:27161136

  1. Water washing effects on metals emission reduction during municipal solid waste incinerator (MSWI) fly ash melting process.

    PubMed

    Chiang, Kung-Yuh; Hu, Yu-Hsin

    2010-05-01

    This study investigated that water washing effects on the metals emission reduction in melting of municipal solid waste incinerator (MSWI) fly ash. Experimental conditions were conducted at liquid-to-solid (L/S) ratio 10, 20, and 100 for water-washing process and its subsequent melting treatment at 1450 degrees C for 2h. The simple water-washing process as a pre-treatment for MSWI fly ash can remove most of the chlorides, leachable salts, and amphoteric heavy metals from the MSWI fly ash, resulting in the washed ash having lowered chlorine content. MSWI fly ashes washed by L/S ratio 10 and above that were melted at 1450 degrees C produced slag containing relatively high vitrificaton ratio of Cu and Pb. Besides, the vitrification ratios of Na, K, Ca, and Mg in washed MSWI fly ash were also higher than that of MSWI fly ash. The results indicated that washed MSWI fly ash can reduce the emission of metallic chlorides during its subsequent melting treatment. PMID:20079621

  2. Comparison of Copper Sorption on Lignite and on Soils of Different Types and Their Humic Acids

    SciTech Connect

    Pekar, M.; Klucakova, M.

    2008-10-15

    We compared the sorption of copper on South Moravian lignite with that on several soils from Slovakia, using batch adsorption at a laboratory temperature of 25{sup o}C followed by a two-step desorption procedure. The results confirmed that lignite has a copper-sorption capacity and copper-binding strength that is comparable to or better than that of the Slovakian soils that we investigated. We compared these results with previously obtained data for sorption on humic acids (HA) isolated from lignite and soils. Although soil constituents other than HA, such as fulvic acids and mineral particles, also control metal sorption, HA bind copper at higher capacity and with greater strength than do the whole matrices of the soils we tested, and lignite showed a greater binding strength for copper than any of these soils. Our results thus far indicate that natural lignite mined in the Czech Republic, or lignite-derived HA, are potential agents for in situ soil remediation.

  3. An overview on characterization, utilization and leachate analysis of biomedical waste incinerator ash.

    PubMed

    Rajor, Anita; Xaxa, Monika; Mehta, Ratika; Kunal

    2012-10-15

    Solid waste management is one of the major global environmental issues, as there is continuous increase in industrial globalization and generation of waste. Solid wastes encompass the heterogeneous mass of throwaways from the urban community as well as the homogeneous accumulations of agricultural, industrial and mineral wastes. Biomedical waste pose a significant impact on health and environment. A proper waste management system should be required to dispose hazardous biomedical waste and incineration should be the best available technology to reduce the volume of this hazardous waste. The incineration process destroys pathogens and reduces the waste volume and weight but leaves a solid material called biomedical waste ash as residue which increases the levels of heavy metals, inorganic salts and organic compounds in the environment. Disposal of biomedical waste ash in landfill may cause contamination of groundwater as metals are not destroyed during incineration. The limited space and the high cost for land disposal led to the development of recycling technologies and the reuse of ash in different systems. In order to minimize leaching of its hazardous components into the environment several studies confirmed the successful utilization of biomedical waste ash in agriculture and construction sector. This paper presents the overview on the beneficial use of ash in agriculture and construction materials and its leachate characteristics. This review also stressed on the need to further evaluate the leachate studies of the ashes and slag for their proper disposal and utilization. PMID:22647736

  4. The Laconia, New Hampshire bottom ash paving project: Volume 3, Physical Performance Testing Report

    SciTech Connect

    1996-03-01

    Bottom ash is the principal waste stream from the combustion of municipal solid waste (MSW). It is comprised of grate ash (97%), the slag material discharged at the end of the grate system, and grate sifting (3%), the material that melts or falls through the grate structure. This project was conducted to demonstrate the feasibility of using municipal solid waste grate ash as an aggregate substitute in the construction of a pavement binder course for a portion of Rt. 3 in Laconia, New Hampshire. The research was conducted over a two year period during 1993 and 1994. This study is the culmination of an earlier two year characterization study between 1990 and 1992 that documented the physical and environmental characteristics of the bottom ash as it was produced at the Concord, N.H. waste-to-energy (@) facility and used in an asphaltic binder course. Together, these two studies provide a complete evaluation of the potential for using grate ash or bottom ash in asphalt binder course or as recycled asphalt pavement (RAP) in base courses in pavements.

  5. Alkali-slag cements for the immobilization of radioactive wastes

    SciTech Connect

    Shi, C.; Day, R.L.

    1996-12-31

    Alkali-slag cements consist of glassy slag and an alkaline activator and can show both higher early and later strengths than Type III Portland cement, if a proper alkaline activator is used. An examination of microstructure of hardened alkali-slag cement pastes with the help of XRD and SEM with EDAX shows that the main hydration product is C-S-H (B) with low C/S ratio and no crystalline substances exist such as Ca(OH){sub 2}, Al (OH){sub 3} and sulphoaluminates. Mercury intrusion tests indicate that hardened alkali-slag cement pastes have a lower porosity than ordinary Portland cement, and contain mainly gel pores. The fine pore structure of hardened alkali-slag cement pastes will restrict the ingress of deleterious substances and the leaching of harmful species such as radionuclides. The leachability of Cs{sup + } from hardened alkali-slag cement pastes is only half of that from hardened Portland cement. From all these aspects, it is concluded that alkali-slag cements are a better solidification matrix than Portland cement for radioactive wastes.

  6. Leaching modelling of slurry-phase carbonated steel slag.

    PubMed

    Costa, G; Polettini, A; Pomi, R; Stramazzo, A

    2016-01-25

    In the present work the influence of accelerated mineral carbonation on the leaching behaviour of basic oxygen furnace steel slag was investigated. The environmental behaviour of the material as evaluated through the release of major elements and toxic metals under varying pH conditions was the main focus of the study. Geochemical modelling of the eluates was used to derive a theoretical description of the underlying leaching phenomena for the carbonated material as compared to the original slag. Among the investigated elements, Ca and Si were most appreciably affected by carbonation. A very clear effect of carbonation on leaching was observed for silicate phases, and lower-Ca/Si-ratio minerals were found to control leaching in carbonated slag eluates as compared to the corresponding untreated slag sample as a result of Ca depletion from the residual slag particles. Clear evidence was also gained of solubility control for Ca, Mg and Mn by a number of carbonate minerals, indicating a significant involvement of the original slag constituents in the carbonation process. The release of toxic metals (Zn, V, Cr, Mo) was found to be variously affected by carbonation, owing to different mechanisms including pH changes, dissolution/precipitation of carbonates as well as sorption onto reactive mineral surfaces. The leaching test results were used to derive further considerations on the expected metal release levels on the basis of specific assumptions on the relevant pH domains for the untreated and carbonated slag. PMID:26489916

  7. Vanadium bioavailability in soils amended with blast furnace slag.

    PubMed

    Larsson, Maja A; Baken, Stijn; Smolders, Erik; Cubadda, Francesco; Gustafsson, Jon Petter

    2015-10-15

    Blast furnace (BF) slags are commonly applied as soil amendments and in road fill material. In Sweden they are also naturally high in vanadium. The aim of this study was to assess the vanadium bioavailability in BF slags when applied to soil. Two soils were amended with up to 29% BF slag (containing 800 mg V kg(-1)) and equilibrated outdoors for 10 months before conducting a barley shoot growth assay. Additional soil samples were spiked with dissolved vanadate(V) for which assays were conducted two weeks (freshly spiked) and 10 months (aged) after spiking. The BF slag vanadium was dominated by vanadium(III) as shown by V K-edge XANES spectroscopy. In contrast, results obtained by HPLC-ICP-MS showed that vanadium(V), the most toxic vanadium species, was predominant in the soil solution. Barley shoot growth was not affected by the BF slag additions. This was likely due to limited dissolution of vanadium from the BF slag, preventing an increase of dissolved vanadium above toxic thresholds. The difference in vanadium bioavailability among treatments was explained by the vanadium concentration in the soil solution. It was concluded that the vanadium in BF slag is sparingly available. These findings should be of importance in environmental risk assessment. PMID:25917693

  8. UTILIZATION OF LIGHTWEIGHT MATERIALS MADE FROM COAL GASIFICATION SLAGS

    SciTech Connect

    Vas Choudhry; Stephen Kwan; Steven R. Hadley

    2001-07-01

    The objective of the project entitled ''Utilization of Lightweight Materials Made from Coal Gasification Slags'' was to demonstrate the technical and economic viability of manufacturing low-unit-weight products from coal gasification slags which can be used as substitutes for conventional lightweight and ultra-lightweight aggregates. In Phase I, the technology developed by Praxis to produce lightweight aggregates from slag (termed SLA) was applied to produce a large batch (10 tons) of expanded slag using pilot direct-fired rotary kilns and a fluidized bed calciner. The expanded products were characterized using basic characterization and application-oriented tests. Phase II involved the demonstration and evaluation of the use of expanded slag aggregates to produce a number of end-use applications including lightweight roof tiles, lightweight precast products (e.g., masonry blocks), structural concrete, insulating concrete, loose fill insulation, and as a substitute for expanded perlite and vermiculite in horticultural applications. Prototypes of these end-use applications were made and tested with the assistance of commercial manufacturers. Finally, the economics of expanded slag production was determined and compared with the alternative of slag disposal. Production of value-added products from SLA has a significant potential to enhance the overall gasification process economics, especially when the avoided costs of disposal are considered.

  9. Utilizing steel slag in environmental application - An overview

    NASA Astrophysics Data System (ADS)

    Lim, J. W.; Chew, L. H.; Choong, T. S. Y.; Tezara, C.; Yazdi, M. H.

    2016-06-01

    Steel slags are generated as waste material or byproduct every day from steel making industries.The potential environmental issues which are related with the slag dump or reprocessing for metal recovery are generally being focused in the research. However the chemistry and mineralogy of slag depends on metallurgical process which is able to determine whether the steel slag can be the reusable products or not. Nowadays, steel slag are well characterized by using several methods, such as X-ray Diffraction, ICP-OES, leaching test and many more. About the industrial application, it is mainly reused as aggregate for road construction, as armour stones for hydraulic engineering constructions and as fertilizers for agricultural purposes. To ensure the quality of steel slag for the end usage, several test methods are developed for evaluating the technical properties of steel slag, especially volume stability and environmental behaviour. In order to determine its environmental behaviour, leaching tests have been developed. The focus of this paper however is on those applications that directly affect environmental issues including remediation, and mitigation of activities that negatively impact the environment.

  10. Characterizing coal-gasifier slag-refractory interactions

    SciTech Connect

    Rawers, James C.; Kwong, Kyei-Sing; Bennett, James P.

    1999-01-01

    To characterize refractory degradation and loss in commercial coal-gasifier combined cycle power systems, cup-type tests were conducted on high chromium-alumina, sinter-bonded refractories under laboratory conditions designed to simulate commercial operations of temperature, atmosphere, and slag interactions. These tests provided qualitative results from which the slag?refractory interactions can be characterized. These high chromium refractories were generally inert with respect to the coal slag components. However, in this study preliminary findings did show (1) iron ( oxide) in the slag reacted with chrome sesquioxide to produce a Cr?Fe spinel at the slag?refractory interface, and (2) chrome was soluble in the molten slag. Comparison of cup-type test results with data from operating commercial plants suggests that the principal loss of refractory material in a coal-gasifier combustion chamber is chrome dissolution into the slag. Tests are currently underway to determine if minor modifications to the combustion process might increase refractory life.

  11. Slag/mud mixtures improve cementing operations in China

    SciTech Connect

    Wu, D.; Peiyan; Huang, B.

    1996-12-23

    The use of blast furnace slag, which is inexpensive and widely available throughout China, can with proper activators and retarders, solidify mud into an excellent cementing material. The use of slag-mix has been somewhat controversial. Some experts claim slag-mix is the most important progress to date in mud-to-cement conversion and has become another choice for cementing practices.They also believed there were no fundamental limitations to its application downhole, and conceivably the material could be used for any well cemented. Other experts have different points of view and thought it might have limits for oil field use. In their studies, the basic mud had to be diluted by 60% or more with water before the blast furnace slag (BFS) was added. Their slag slurries showed a high incidence of cracking and apparent brittle nature, bad settling stability, and volume shrinkage. To date, the Chinese National petroleum Corp. (CNPC) has used mud solidification by slag successfully on 22 cementing jobs in the Sichun, Changqing, Jidong, and Shengli oil fields.The major purpose of these investigations was to determine the application of slag-mix technology to various cementing operations.

  12. Calibration-free electrical conductivity measurements for highly conductive slags

    SciTech Connect

    MACDONALD,CHRISTOPHER J.; GAO,HUANG; PAL,UDAY B.; VAN DEN AVYLE,JAMES A.; MELGAARD,DAVID K.

    2000-05-01

    This research involves the measurement of the electrical conductivity (K) for the ESR (electroslag remelting) slag (60 wt.% CaF{sub 2} - 20 wt.% CaO - 20 wt.% Al{sub 2}O{sub 3}) used in the decontamination of radioactive stainless steel. The electrical conductivity is measured with an improved high-accuracy-height-differential technique that requires no calibration. This method consists of making continuous AC impedance measurements over several successive depth increments of the coaxial cylindrical electrodes in the ESR slag. The electrical conductivity is then calculated from the slope of the plot of inverse impedance versus the depth of the electrodes in the slag. The improvements on the existing technique include an increased electrochemical cell geometry and the capability of measuring high precision depth increments and the associated impedances. These improvements allow this technique to be used for measuring the electrical conductivity of highly conductive slags such as the ESR slag. The volatilization rate and the volatile species of the ESR slag measured through thermogravimetric (TG) and mass spectroscopy analysis, respectively, reveal that the ESR slag composition essentially remains the same throughout the electrical conductivity experiments.

  13. Slag analysis with laser-induced breakdown spectrometry.

    PubMed

    Kraushaar, M; Noll, R; Schmitz, H U

    2003-10-01

    Laser-induced breakdown spectrometry (LIBS) has been applied for multi-elemental analysis of slag samples from a steel plant. In order to avoid the time-consuming step of sample preparation, the liquid slag material can be filled in special probes. After cooling of the liquid slag and solidification, the samples can be analyzed with LIBS. Chemical analysis of slag is an essential input parameter used for numerical simulations to control liquid steel processing. The relative variation range of element concentrations in slag samples from steel production can amount to up to 30%. A multivariate calibration model is used to take into account matrix effects caused by these varying concentrations. By optimizing the measuring parameters as well as the calibration models, an agreement between the standard X-ray fluorescence (XRF) analysis and LIBS analysis in terms of the coefficient of determination r2 of 0.99 for the main analytes CaO, SiO2, and Fetot of converter slag samples was achieved. The average repeatability of the LIBS measurement for these elements in terms of the relative standard deviation of the determined concentration is improved to less than 1.0%. With these results, the basis is established for future on-line applications of LIBS in the steel-making industry for slag analysis. PMID:14639759

  14. Effects of leachant temperature and pH on leachability of metals from fly ash. A case study: Can thermal power plant, province of Canakkale, Turkey.

    PubMed

    Baba, Alper; Gurdal, Gulbin; Sengunalp, Fatma; Ozay, Ozgur

    2008-04-01

    Lignite powered electric generation plants result in increasing environmental problems associated with gaseous emissions and the disposal of ash residues. Especially, low quality coals with high ash content cause enormous quantities of both gaseous and solid fly ash emissions. The main problem is related to the disposal of fly ash, which, in many cases, contains heavy metals. It is known that toxic trace metals may leach when fly ash is in contact with water. In this study, fly ash samples obtained from the thermal power plant in the town of Can in Turkey were investigated for leachability of metals under different acidic and temperature conditions. The experimental results show that a decrease in pH of the leachant favors the extraction of metal ions from fly ash. A significant increase in the extraction of arsenic, cadmium, chromium, zinc, lead, mercury, and selenium ions from the ash is attributed to the instability of the mineral phases. These heavy metals concentrations increase with respect to increasing acidic conditions and temperature. Peak concentrations, in general, were found at around 30 degrees C. PMID:17588209

  15. Pb(II) removal from aqueous solution by a low-cost adsorbent dry desulfurization slag

    NASA Astrophysics Data System (ADS)

    Wu, Qiong; You, Ruirong; Clark, Malcolm; Yu, Yan

    2014-09-01

    A collectable and non-sintered material prepared as hollow cylindrical shaped pellet from dry desulfurization slag (FGD ash) and ordinary Portland cement (OPC) for wastewater treatments is tested. The characteristic results of powder X-ray diffraction (XRD) and infrared absorption spectroscopy (IR) show that -OH, CO32-, SO32- and SO42- are the possible functional groups responsible for Pb uptake. Adsorption data indicate that Pb removal is pH dependent and optimal at pH 6, with a very rapid initial removal that reaches equilibrium in about 90 min. A maximum removal of 99.2% is seen for 5 mg/L (pH of 6); higher initial Pb concentrations reduce overall removal efficiencies, but generate higher surface loadings. Adsorption process correlates well with both Langmuir and Freundlich models, although the Langmuir isotherm is more favored, providing a maximum adsorption capacity (Qm) of 130.2 mg/g (13 wt%). Pseudo-second order rate kinetic model best describes the Pb removal, and calculated RL values between 0 and 1, indicate a favored adsorption process that is chemisorption limited. SEM and EDAX analysis of the surface and fracture surface show that Pb occurs as surface precipitates and that Pb is not distributed to the inner core of the pellet. This study demonstrates that dry FGD ash could be successfully used for wastewater Pb removal.

  16. Coal gasifier wall protection system - slag shedding technique

    SciTech Connect

    Sanscrainte, W.; Marshall, D.

    1982-12-01

    This report describes how a long-term slag shedding experiment was developed. The results of the evaluation of various materials and techniques for protecting gasifier walls from damaging environments while maintaining high efficiency and good cooling properties are presented. This report states that an A 387 alloy appears to be an acceptable gasifier wall material. Cyclic slag shedding and slag thickness are dependent on cooling level, temperature and surface roughness. A water-cooled test section was operated successfully at full-scale operating temperature.

  17. Effective Diffusivity and Spalling Models for Slagging Coal Gasifiers

    SciTech Connect

    Williford, Rick E.; Johnson, Kenneth I.; Sundaram, S. K.; Pilli, Siva Prasad

    2008-01-08

    A major impact on the economics of coal gasification is the spalling degradation of hot-face refractories in slagging coal gasifiers. Two predictive models for spalling have been previously proposed and benchmarked. Both models express molten slag ingress into the porous refractory in terms of an effective diffusivity, a formulation for which is developed in the present Communication. The results appear useful for predicting the lifetimes of refractories in slagging coal gasifiers, and for determining whether the spall originated from tensile or compressive mechanisms.

  18. Allowable gas temperature at outlet from furnace subject to slagging

    SciTech Connect

    A.N. Alekhnovich; N.V. Artem'eva; V.V. Bogomolov

    2007-03-15

    The paper is devoted to substantiation and prediction of the allowable gas temperature at the outlet from a furnace subject to slagging. The non-optimality of values recommended by effective methodical instructions regarding the design of furnace devices is demonstrated. Utilizing knowledge gained from temperature measurements in boilers, and the situation regarding the slagging of heating surfaces located at the outlet from the furnace, new, frequently higher values are proposed. A method for evaluating the allowable gas temperature at the outlet from a furnace subject to slagging is suggested on the basis of data regarding the chemical composition of the mineral portion of coals.

  19. Study on Apparent Viscosity and Structure of Foaming Slag

    NASA Astrophysics Data System (ADS)

    Martinsson, Johan; Glaser, Björn; Sichen, Du

    2016-07-01

    Foaming slag was generated using induction heating. The foam was found non-Newtonian having much higher apparent viscosity compared to the dynamic viscosity of pure slag. Quenched foam was examined. The appearance of the foaming slag was very different from silicone oil-gas foam. The size of gas bubbles ranged from 0.1 to 4 mm (while in the case of silicone oil, 1 to 2 mm). The gas fraction in the foam was considerably lower than in the case of silicone oil.

  20. Initial stages of coal slag interaction with high chromia sesquioxide refractories

    SciTech Connect

    Rawers, James C.; Iverson, Larissa; Collins, Wesley K.

    2002-02-01

    Slagging coal gasifiers operate at temperatures as high as 1650◦C in a reducing environment, requiring combustion chambers to be lined with refractories. The liner materials of choice are semi-porous high chromia refractories. Recently, a new series of high-chromia aluminia sesquioxide refractories have been developed. Both long term and short term tests are being conducted to evaluate the performance of these materials. In this study, the initial stage of slag-refractory interactions was analyzed. Samples of gasifier slag were compacted and placed upon the surface of these new chromia refractories and the temperature was raised consistent with start-up operating conditions of commercial gasifiers. The slag was completely molten by the time the furnace achieved a temperature consistent with gasifier operation conditions: 1350◦C. Measurement of the slag contact angle, slag spread along the slag-refractory interface, and the loss of slag due to slag infusion into the refractory were monitored by camera. Analysis suggests a single phenomenon with an activation energy of approximately 54 kcal may be the controlling factor. Cross-section analysis of the sample and analysis of slag chemistry indicate that slag infusion preceded the slag-refractory interface front movement and that the iron component of the slag was becoming concentrated at the slag-refractory interface leading to the formation of a chromium-iron spinel phase. Results of these short term tests are critical in characterizing and understanding the results long term slag-refractory interactions.

  1. Initial stages of coal slag interaction with high chromia sesquioxide refractories

    SciTech Connect

    Rawers, J.C.; Iverson, L.; Collins, W.K.

    2002-02-01

    Slagging coal gasifiers operate at temperatures as high as 1650°C in a reducing environment, requiring combustion chambers to be lined with refractories. The liner materials of choice are semi-porous high chromia refractories. Recently, a new series of high-chromia aluminia sesquioxide refractories have been developed. Both long term and short term tests are being conducted to evaluate the performance of these materials. In this study, the initial stage of slag-refractory interactions was analyzed. Samples of gasifier slag were compacted and placed upon the surface of these new chromia refractories and the temperature was raised consistent with start-up operating conditions of commercial gasifiers. The slag was completely molten by the time the furnace achieved a temperature consistent with gasifier operation conditions: 1350°C. Measurement of the slag contact angle, slag spread along the slag-refractory interface, and the loss of slag due to slag infusion into the refractory were monitored by camera. Analysis suggests a single phenomenon with an activation energy of approximately 54 kcal may be the controlling factor. Cross-section analysis of the sample and analysis of slag chemistry indicate that slag infusion preceded the slag-refractory interface front movement and that the iron component of the slag was becoming concentrated at the slag-refractory interface leading to the formation of a chromium-iron spinel phase. Results of these short term tests are critical in characterizing and understanding the results long term slag-refractory interactions.

  2. Effect of P2O5 and FetO on the Viscosity and Slag Structure in Steelmaking Slags

    NASA Astrophysics Data System (ADS)

    Wang, Z. J.; Shu, Q. F.; Sridhar, S.; Zhang, M.; Guo, M.; Zhang, Z. T.

    2015-04-01

    The present paper investigates the influence of P2O5 and FetO on the viscosity and structure of steelmaking slags. An understanding of the viscous behavior and structure of FetO-bearing smelting slags is essential to control the dephosphorization in steelmaking process and to efficiently recycle the phosphorus from steelmaking slags. It is found that the viscosity of CaO-SiO2-Al2O3-MgO-FetO-P2O5 slags slightly increases with increasing P2O5 content, while the viscosity decreases with increasing FetO content. The degree of the polymerization of quenched slags, determined from Raman spectra, is found to increase with increasing P2O5 content and decrease with increasing FetO content. It is also noted that the peaks of Raman spectra between 800 and 1200 cm-1 were nearly absent at the FetO content of 22.46 wt pct; whereas according to 29Si MAS-NMR and FTIR analysis, it is clearly seen that the [SiO4]-tetrahedra-related peaks existed even for the same slag. This may confirm that small quantities of extra-framework iron species can absorb the Raman scattering and damp the Raman signal intensity and the presence of FetO in the slag does not necessarily eliminate [SiO4]-tetrahedra.

  3. Engineering Model for Ash Formation

    Energy Science and Technology Software Center (ESTSC)

    1994-12-02

    Ash deposition is controlled by the impaction and sticking of individual ash particles to heat transfer surfaces. Prediction of deposition therefore requires that the important factors in this process be predictable from coal and operational parameters. Coal combustion, boiler heat transfer, ash formation, ash particle aerodynamic, and ash particle sticking models are all essential steps in this process. The model described herein addresses the prediction of ash particle size and composition distributions based upon combustionmore » conditions and coal parameters. Key features of the model include a mineral redistribution routine to invert CCSEM mineralogical data, and a mineral interaction routine that simulates the conversion of mineral matter into ash during coal burning and yields ash particle size and composition distributions.« less

  4. A new cost-effective method to mitigate ammonia loss from intensive cattle feedlots: application of lignite

    NASA Astrophysics Data System (ADS)

    Chen, Deli; Sun, Jianlei; Bai, Mei; Dassanayake, Kithsiri B.; Denmead, Owen T.; Hill, Julian

    2015-11-01

    In open beef feedlot systems, more than 50% of dietary nitrogen (N) is lost as ammonia (NH3). Here we report an effective and economically-viable method to mitigate NH3 emissions by the application of lignite. We constructed two cattle pens (20 × 20 m) to determine the effectiveness of lignite in reducing NH3 emissions. Twenty-four steers were fed identical commercial rations in each pen. The treatment pen surface was dressed with 4.5 kg m-2 lignite dry mass while no lignite was applied in the control pen. We measured volatilised NH3 concentrations using Ecotech EC9842 NH3 analysers in conjunction with a mass balance method to calculate NH3 fluxes. Application of lignite decreased NH3 loss from the pen by approximately 66%. The cumulative NH3 losses were 6.26 and 2.13 kg N head-1 in the control and lignite treatment, respectively. In addition to the environmental benefits of reduced NH3 losses, the value of retained N nutrient in the lignite treated manure is more than $37 AUD head-1 yr-1, based on the current fertiliser cost and estimated cost of lignite application. We show that lignite application is a cost-effective method to reduce NH3 loss from cattle feedlots.

  5. A new cost-effective method to mitigate ammonia loss from intensive cattle feedlots: application of lignite

    PubMed Central

    Chen, Deli; Sun, Jianlei; Bai, Mei; Dassanayake, Kithsiri B.; Denmead, Owen T.; Hill, Julian

    2015-01-01

    In open beef feedlot systems, more than 50% of dietary nitrogen (N) is lost as ammonia (NH3). Here we report an effective and economically-viable method to mitigate NH3 emissions by the application of lignite. We constructed two cattle pens (20 × 20 m) to determine the effectiveness of lignite in reducing NH3 emissions. Twenty-four steers were fed identical commercial rations in each pen. The treatment pen surface was dressed with 4.5 kg m−2 lignite dry mass while no lignite was applied in the control pen. We measured volatilised NH3 concentrations using Ecotech EC9842 NH3 analysers in conjunction with a mass balance method to calculate NH3 fluxes. Application of lignite decreased NH3 loss from the pen by approximately 66%. The cumulative NH3 losses were 6.26 and 2.13 kg N head−1 in the control and lignite treatment, respectively. In addition to the environmental benefits of reduced NH3 losses, the value of retained N nutrient in the lignite treated manure is more than $37 AUD head−1 yr−1, based on the current fertiliser cost and estimated cost of lignite application. We show that lignite application is a cost-effective method to reduce NH3 loss from cattle feedlots. PMID:26584639

  6. The effect of lignite on nitrogen mobility in a low-fertility soil amended with biosolids and urea.

    PubMed

    Paramashivam, Dharini; Clough, Tim J; Carlton, Anna; Gough, Kelsi; Dickinson, Nicholas; Horswell, Jacqui; Sherlock, Robert R; Clucas, Lynne; Robinson, Brett H

    2016-02-01

    Lignite has been proposed as a soil amendment that reduces nitrate (NO3(-)) leaching from soil. Our objective was to determine the effect of lignite on nitrogen (N) fluxes from soil amended with biosolids or urea. The effect of lignite on plant yield and elemental composition was also determined. Batch sorption and column leaching experiments were followed by a lysimeter trial where a low fertility soil was amended with biosolids (400 kg N/ha equivalent) and urea (200 kg N/ha equivalent). Treatments were replicated three times, with and without lignite addition (20 t/ha equivalent). Lignite did not reduce NO3(-) leaching from soils amended with either biosolids or urea. While lignite decreased NO3(-) leaching from an unamended soil, the magnitude of this effect was not significant in an agricultural context. Furthermore, lignite increased cumulative N2O production from soils receiving urea by 90%. Lignite lessened the beneficial growth effects of adding biosolids or urea to soil. Further work could investigate whether coating urea granules with lignite may produce meaningful environmental benefits. PMID:26615483

  7. Surface restructuring of lignite by bio-char of Cuminum cyminum - Exploring the prospects in defluoridation followed by fuel applications

    NASA Astrophysics Data System (ADS)

    Msagati, T. A. M.; Mamba, B. B.; Sivasankar, V.; Omine, Kiyoshi

    2014-05-01

    Recently, there has been an interest in the areas of developing new carbon materials for fluoride removal applications. The development of new carbon materials is of recent choice which involves the synthesis of hybrid carbon from various sources. In this context, the present contribution is made to focus on the study the restructured surface of lignite using a bio-material called Cuminum cyminum. The restructured lignite (RSL) was synthesized with an improved carbon content of 13% and its BET surface area was found to be 3.12 times greater than lignite (L). The amorphous nature of lignite and RSL was quite explicable from XRD studies. SEM studies exhibited a fibrous and finer surface of lignite which was well restructured into a semi-melt (5 μm) surface for RSL. Defluoridation potential of Restructured Lignite (15.8 mg g-1) was greater than the lignite (13.8 mg g-1) at pH 7.93 ± 0.03. Kinetic and isotherm parameters derived from various models helped in comprehending the nature and dynamics of fluoride sorption. Both the normal and the restructured lignite were found to be consistent with its fluoride uptake of 57% and 60% respectively even after fifth cycle of regeneration. High heating values of 22.01 MJ kg-1 and 26.90 MJ kg-1 respectively for lignite and RSL deemed their additional application as fuel materials.

  8. RECLAMATION OF ALKALINE ASH PILES

    EPA Science Inventory

    The objective of the study was to develop methods for reclaiming ash disposal piles for the ultimate use as agricultural or forest lands. The ashes studied were strongly alkaline and contained considerable amounts of salts and toxic boron. The ashes were produced from burning bit...

  9. Engineered refractoriers for slagging coal gasifiers

    SciTech Connect

    Bennett, James P.; Kwong, Kyei-Sing; Powell, Cynthia A; Krabbe, Rick; Thomas, Hugh

    2005-01-01

    The widespread commercial adaptation of slagging gasifier technology to produce power, fuel, and/or chemicals from coal will depend in large measure on the technology's ability to prove itself both economic and reliable. Improvements in gasifier reliability, availability, and maintainability will in part depend on the development of improved structural materials with longer service life in this application. Current generation refractory materials used to line the gasifier vessel, and contain the gasification reaction, often last no more than three to 18 months in commercial applications. The downtime required for tear-out and replacement of these critical materials results in gasifier on-line availabilities that fall short of targeted goals. In this talk we will discuss the development of improved refractory materials engineered specifically for longer service life in this application, with emphasis on the design of new refractories that contain little or no chrome.

  10. Induction slag reduction process for purifying metals

    DOEpatents

    Traut, Davis E.; Fisher, II, George T.; Hansen, Dennis A.

    1991-01-01

    A continuous method is provided for purifying and recovering transition metals such as neodymium and zirconium that become reactive at temperatures above about 500.degree. C. that comprises the steps of contacting the metal ore with an appropriate fluorinating agent such as an alkaline earth metal fluosilicate to form a fluometallic compound, and reducing the fluometallic compound with a suitable alkaline earth or alkali metal compound under molten conditions, such as provided in an induction slag metal furnace. The method of the invention is advantageous in that it is simpler and less expensive than methods used previously to recover pure metals, and it may be employed with a wide range of transition metals that were reactive with enclosures used in the prior art methods and were hard to obtain in uncontaminated form.

  11. Numerical Investigation of Slag Behavior for RSRM

    NASA Technical Reports Server (NTRS)

    Liaw, P.; Chen, Y.-S.; Shang, H.; Shih, M.; Doran, D.; Stewart, E.

    1996-01-01

    It is known that the flow field of the redesigned solid rocket motor (RSRM) is very complicated due to the complex characteristics of turbulent multi-phase flow, chemical reaction, particle combustion, evaporation, breakup and agglomeration etc. It requires multi-phase calculations, chemical reaction simulation, and particle combustion, evaporation, and breakup models to obtain a better understanding of thermophysics for the RSRM design using numerical methods. Also, the slag buildup due to the molten particles is another factor affecting the performance of the RSRM. To achieve this goal, the volume of fluid (VOF) method is used to capture the free surface motion so as to simulate the accumulation of the molten particles (slag) of the RSRM. A finite rate chemistry model is used to simulate the chemical reaction effects. For multi-phase calculations, the Hermsen combustion model is used for the aluminum particle combustion analysis and the Taylor Analogy Breakup (TAB) model is used for the particle breakup analysis. An interphase mas-exchange model introduced by Spalding is used for the evaporation calculation. The particle trajectories are calculated using a one-step implicit method for several groups of particle sizes by which the drag forces and heat fluxes are then coupled with the gas phase equations. The preliminary results predicted a reasonable physical simulation of the particle effects using a simple two dimensional solid rocket motor configuration. It shows that the AL/AL2O3 particle sizes are reduced due to the combustion, evaporation, and breakup. The flow field is disturbed by the particles. Mach number distributions in the nozzle are deformed due to the effect of particle concentrations away from the center line.

  12. 180. Jet Lowe, Photographer July 1978. VIEW FROM SLAG DUMP ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    180. Jet Lowe, Photographer July 1978. VIEW FROM SLAG DUMP OF (LEFT TO RIGHT) RAILROAD WAREHOUSE (1901); BRIQUETTING PLANT (1906); CUPOLA BUILDING (1898) AND MACHINE SHOP (1907). - Quincy Mining Company, Hancock, Houghton County, MI

  13. Monitoring the Thickness of Coal-Conversion Slag

    NASA Technical Reports Server (NTRS)

    Walsh, J. V.

    1984-01-01

    Technique adapts analogous ocean-floor-mapping technology. Existing ocean floor acoustic technology adapted for real-time monitoring of thickness and viscosity of flowing slag in coal-conversion processing.

  14. Waste Heat Recovery from Blast Furnace Slag by Chemical Reactions

    NASA Astrophysics Data System (ADS)

    Qin, Yuelin; Lv, Xuewei; Bai, Chenguang; Qiu, Guibao; Chen, Pan

    2012-08-01

    Blast furnace (BF) slag, which is the main byproduct in the ironmaking process, contains large amounts of sensible heat. To recover the heat, a new waste heat-recovery system—granulating molten BF slag by rotary multinozzles cup atomizer and pyrolyzing printed circuited board with obtained hot BF slag particle—was proposed in this study. The feasibility of the waste heat-recovery system was verified by dry granulation and pyrolyzation experiments. The energy of hot BF slag could be converted to chemical energy through the pyrolysis reaction, and a large amount of combustible gas like CO, H2, C m H n , and CH4 can be generated during the process.

  15. British Gas/Lurgi Slagging Gasifier a springboard into synfuels

    SciTech Connect

    Sharman, R.B.; Lacey, J.A.; Scott, J.E.

    1981-01-01

    The most developed and widely used fixed bed pressure gasification systems are based on the Lurgi Gasification Process. The British Gas/Lurgi Slagging Gasifier results from the joing together of British Gas Corporation and Lurgi Company technology. The British Gas Slagging Gasification technology offers significant advantages over dry bottom Lurgi and other fixed bed gasification systems. The slagging gasifier has more advantages than disadvantages when compared with entrained flow gasifiers and these advantages are sufficient to give it an economic advnatage in most process situations. The processing of crude Slagging Gasifier gas and the multifarious uses of the resulting clean gas in the chemicals, power generation and fuel gas fields are described. The environmental impact of the process is also discussed and plans for commercialization are considered. 21 refs.

  16. Characterization of structure and thermophysical properties of three ESR slags

    NASA Astrophysics Data System (ADS)

    Plotkowski, A.; deBarbadillo, J.; Krane, Matthew J. M.

    2016-07-01

    The structure and properties of electroslag remelting (ESR) slags were characterized. Slags samples of three compositions were obtained from industrial remelting processes at Special Metals Corporation and from casting in a laboratory vacuum induction melter. The structure of the slag samples was observed using optical and electron microscopy, and phases were identified and their relative amounts quantified using X-ray diffraction. Laser flash thermal diffusivity, density, and differential scanning calorimetry measurements for specific heat were performed to determine the bulk thermal conductivity of the samples. Sample porosity was measured as a function of depth using a serial sectioning technique, and a onedimensional computational model was developed to estimate the thermal conductivity of the fully dense slags. These results are discussed in context with previous studies, and opportunities for future research are identified. AFRL Case Number: 88ABW-2015-1871.

  17. Use of granular slag columns for lead removal.

    PubMed

    Dimitrova, S V

    2002-09-01

    The use of granular blast furnace slag (GBFS)-packed columns to treat lead-containing solutions has been investigated. The results obtained indicated that the slag usage rate decreased with increasing flow velocity, particle size, initial lead concentration and decreasing with bed height. Lead removed selectively in the presence of other heavy metal ions. High concentrations of sodium and especially calcium in the solutions impeded the uptake of lead. For 20 mg l(-1) lead concentration an empty bed contact time greater of 4 min provided to efficient use of the slag bed. Column pH was an important parameter to lead removal under dynamic conditions and reflected the influence of the investigated factors. During all runs lead breakthrough coincided with an abrupt drop in effluent pH. The apparent mechanisms of lead removal in GBFS column are sorption (ion exchange and adsorption) on the slag surface and precipitation. PMID:12405409

  18. Space Shuttle solid rocket motor slag expulsion mechanisms

    NASA Technical Reports Server (NTRS)

    Hopson, Charles B.

    1995-01-01

    A 13 psi pressure perturbation occurred at approximately 68 seconds on the right Redesigned Solid Rocket Motor (RSRM) during the STS-54 space shuttle mission. While pressure perturbations are a normal characteristic of RSRM operation, the magnitude of the STS-54 perturbation and the resulting thrust imbalance between the left and right motors was outside of flight experience. A joint Marshall Space Flight Center (MSFC) and Thiokol Corporation (RSRM manufacturer) team soon narrowed the probable cause to a temporary nozzle restriction due to slag expulsion. In support of the team, Rockwell Aerospace performed fluid finite element simulations and vehicle flight dynamic correlations to investigate possible slag expulsion mechanisms responsible for pressure perturbations. Results of the simulations and analyses provided evidence that the combination of flight induced accelerations acting on accumulated slag and nozzle vectoring were the most probable cause of RSRM slag expulsion.

  19. WORKER REMOVING SLAG FROM THE MOLTEN METAL BATH IN THE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    WORKER REMOVING SLAG FROM THE MOLTEN METAL BATH IN THE ELECTRIC FURNACE AFTER ADDING A CHEMICAL COAGULANT TO FORCE IT TO THE SURFACE. - Southern Ductile Casting Company, Melting, 2217 Carolina Avenue, Bessemer, Jefferson County, AL

  20. Experimental Investigation and Modeling of Copper Smelting Slags

    NASA Astrophysics Data System (ADS)

    Starodub, Konstantin; Kuminova, Yaroslava; Dinsdale, Alan; Cheverikin, Vladimir; Filichkina, Vera; Saynazarov, Abdukahhar; Khvan, Alexandra; Kondratiev, Alex

    2016-07-01

    Effective extraction of copper from sulfide ores requires careful operation of a copper smelter, which in turn depends very much on chemistry of the feed and resulted slag and matte. For example, chemical composition of copper smelting slags has to be in a certain range to ensure that their properties are within specific limits. Disobeying these rules may lead to complications in smelting operation, poor quality of the copper products, and premature shutdown of the copper smelter. In the present paper the microstructure and phase composition of slags from the Almalyk copper flash smelter were investigated experimentally and then modeled thermodynamically to evaluate potential ways of improvement and optimization of the copper smelting process and its products. The slag samples were taken at different stages of the copper smelting process: on slag tapping, after slag transportation to a deposition site, and at the site. Experimental investigation included the XRD, XRF, and SEM techniques, which were also confirmed by the traditional wet chemistry analysis. Thermodynamic modeling was carried out using thermochemical software package MTDATA, which enables thermodynamic and physical properties of the matte, slag, and gas phases to be calculated in a wide range of temperatures, pressures, and chemical compositions. In addition, slag viscosities and corresponding matte settling rates were estimated using the modified Urbain and Utigard-Warczok models, and the Hadamard-Rybczynski equation, respectively. It was found that the copper content in the slags may vary significantly depending on the location of slag sampling. Cu was found to be present as sulfide particles, almost no Cu was found to be dissolved in the slag. Analysis of microstructure and phase composition showed that major phase found in the samples is fayalite, while other phases are complex spinels (based on magnetite), different sulfides, and a glass-like phase. Thermodynamic calculations demonstrated the