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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. 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.

  4. 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.

  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

    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 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

  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. 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

  14. 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.

  15. 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

  16. 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

  17. 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.

  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. 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

  11. 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.

  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. 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

  14. 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.

  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. 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.

  2. 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

  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. 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.

  11. 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.

  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. 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.

  3. 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.

  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. 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.

  13. 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.

  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. (Bioprocessing of lignite coals using reductive microorganisms)

    SciTech Connect

    Crawford, D.L.

    1990-01-01

    The objectives of this report are to: (1) characterize selected aerobic bacterial strains for their abilities to depolymerize lignite coal polymers, and isolate and identify the extracellular enzymes responsible for depolymerization of the coal; (2) characterize selected strictly anaerobic bacteria, that were previously shown to reductively transform coal substructure model compounds, for the ability to similarly transform polymeric coal; and (3) isolate more strains of anaerobic bacteria by enrichment using additional coal substructure model compounds and coal as substrates.

  4. 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.

  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.