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02296 Sulfur forms in coal and desulfurization characteristics
0 1 So/id fuels (preparation)
00/02285 Composition of carbonaceous deposits and catalyst deactivation in the early stages of the hydrocracking of a coal extract Begon, V. c/ ul. Fiircl, 1999, 7X, (6), 681-688. Carbonaceous deposits on finely dispersed MO& particulates and a NiMosupported catalyst, recovered from coal extract hydrocracking experiments, have been examined. Large surges in carbon deposition on catalyst surfaces were observed when using fresh catalyst and fresh feed. When using fresh feed with re-used catalyst, additional but smaller surges in deposition were found. The composition of the deposits appear to reflect, at least in part, the composition of the coal liquefaction extract. The relative stability in the amounts of carbonaceous deposit at reaction times longer than 2 h mirrors earlier findings suggesting that deactivation of the catalyst after the first 2 h of usage (up to 6 h) was marginal. Most of the deposition of carbonaceous material was found to precede completion of the activation (by sulfidation) of the catalysts. Moreover, much greater loadings of deposits were found on the finely dispersed sulfided-molybdenum catalyst compared with the supported NiMo/~-AlzO-i. Nevertheless, broadly comparable conversions of + 450°C boiling fractions have earlier been observed in the presence of the two catalysts, at reaction times longer than 30 min. Both these catalysts appear to function at their observed levels of activity, while carrying high levels of carbonaceous deposits. These findings tend to confirm earlier work suggesting that carbonaceous deposits might act as a permeable layer, and perhaps act as a reservoir of hydrogen-shuttling hydrogen from the liquid phase to molecules on the catalyst surface. 00102286 Development tendency of MDEA in desulfurization Wang, Q. and Huang, G. Gucmg~r~ng Huqong, 1999, I, 43-44, 47. (In Chinese) The absorption mechanism of MDEA is introduced to acidic gas in this review, the application of MDEA in desulfurization is also considered. 00/02287 Enhanced NO, reduction by interaction of nitrogen and sodium compounds in the reburning zone Zamansky, V. M. er nl. Symp. iInr./ Comhusf., /Proc./, 1998, 2, 3001-3008. This paper analyses the significant factors that affect NO, reduction performance in the advanced reburning-rich process (AR-Rich), which is a combination of reburning with a nitrogen agent and sodium carbonate injection into the reburning zone. These factors include the effects of chemical composition and stoichiometric ratio in the reburning zone, temperature of nitrogen-agent and sodium injections and the presence and concentration of sodium. Experiments in 30 and 300 kW combustors demonstrate that nitrogen oxide reduction is improved by injection of nitrogen-agents (urea or ammonia) in the reburning zone and can be further enhanced up to about 90% by small quantities of sodium carbonate (lo-15 ppm) added to aqueous nitrogen-agents. The delay from reburning fuel to nitrogen-agent injection affects the level of nitrogen oxide reduction. Sodium promoters broaden and deepen the temperature window of nitrogen oxide reduction with maximum values in the range of 1350-1550 K, allowing greater flexibility in installation. AR-Rich is dependent on mixing and droplet evaporation times, Performance is generally improved by longer mixing times. By using three kinetic codes and a detailed chemical mechanism, modelling helps in the interpretation of experimental results, including mixing regimes and provides insight into the internal chemical processes and reaction trends that govern the behaviour of this reacting system. During the selection of the injection nozzles, the predicted impacts of mixing provide some guidance. An identification of chemical reactions responsible for nitrogen-sodium interaction under fuel-rich conditions are also included. For experimental and modelling the results the observed trends seem to be very similar. 00102288 Investigation of desulfurization and sulfur analysis method in hydropyrolysis of coal Liu, L. CI al. Meircm Zhuunhrru, 1999, 22, (2), 39-42. (In Chinese) The desulfurization effect of hydropyrolysis was studied with two kinds of high sulfur coal. Suitable conditions are selected to analyse sulfur contents in raw coal, solid and liquid products using an elemental analyser. The results showed that high desulfurization obtained in hydropyrolysis desulfurization and sulfur distribution differed with each type of coal.
The effect of reduction on particular sulfur compounds is discussed. It was found that reduction in the potassium-liquid ammonia system led to cleavage of carbon-sulfur bonds, appearance of thiol groups, and the partial removal of pyrite and sulfates from the coal whereas the content of elemental sulfur did not change significantly. 00/02291 Removal of thiophene from benzene from coal source by liquid adsorption on modified ZSM-5 synthetic reolite Tan, X. and Wang, X. Chin. 1. Chem. Eng.. 1999, 7, (I), 91-94. The investigation presented is concerned with the removal of thiophene from benezene by adsorption on Cu- and La-exchanged ZSM-5 synthetic zeolite. 00/02292 Semi-industrial scale investigations into NO, emissions control using coal-over-coal reburn techniques Morgan, D. J. er al. Symp. (Inr.) Cornbust., [Proc.], 1998, 2. 304553051. In order to meet the present and future legislation for boiler emissions, the technique of reburning should be considered. Reburning also has the potential to provide NO, reduction with reasonable capital expenditure. The technique has not been applied extensively in new or retrofit applications and this may be because of the complexity of designing a new boiler or modifying an existing one and a scarcity of research information available to aid in this design. Other factors preventing the implementation of the reburning technique are the perceived problem of carbon burnout and the flame stability over a wide range of boiler operating conditions. Reburning has been demonstrated to be effective in a semiindustrial scale facility and the results confirm that the mechanism is suitable for retrofit application. NO, reductions greater than 77% were achieved, relative to a type-11 classification flame, when reburning high- and medium-volatile coal in various combinations. Overall, the most promising combinations for reburning were a low- or high-volatile coal as the primary fuel and a high-volatile, highly reactive coal as the reburn fuel. Typically, for effective NO, reduction, reburn fuel fractions greater than 10% were required in combination with a primary zone stoichiometry less than 0.9. Some features of chemical composition, structure 00102293 and reactive ability of Kansk-Achinsk lignite modified by ozone treatment Sharypov, V. I. er al. Fuel, 1999, 78. (6). 663-666. A study on the influence of ozonization of Kansk-Achinsk lignite on the chemical composition, structure and modified lignite reactivity in hydrogenation processes with different solvents and pyrite catalysts. The chemical analysis data indicates that the incorporation of oxygen into the organic matter of lignite occurs during ozonization. X-ray diffraction and electron paramagnetic resonance techniques were used to determine that ozonization causes the loosening of the lignite structure. Lignite modified by ozone treatment is more reactive, than untreated lignite, in hydrogenation reactions at 380-430°C in the presence of pyrite catalyst. 00102294 Study on enhancing desulfurization of coal by oxidizing coal selectively with Hz02 Liang, Y. et al. Meirun Zhuanhua, 1997, 20, (4). 80-85. (In Chinese) The Box-Wilson experimental procedure was used to study the preoxidization Illinois Basin coal (IBC-108) with HzOz and desulfurizing the pre-oxidized coal with formic acid. The pre-oxidation of coal with HzOz significantly enhanced the desulfurization of coal and that the removal of sulfur from the coal increased with the increasing amount of Hz02. Under the experimental conditions 500°C and 4.96-15.11 MPa) the maximum removal of 74.2% total sulfur and 73.3% organic sulfur was achieved, gaseous HzS was the main product. The mechanism of enhancing desulfurization of the coal by pre-oxidizing selectively with HzOz was also discussed.
00102289 Manufacturing clean coal by extraction with CS,-NMP mixed solvent Yuan, X. r( al. Meirun Zhuunhira. 1999. 22, (2) 53-55. (In Chinese) An analysis of an extract of Pangzhuang coal (Xuzhou), obtained by extraction with carbon-disulfide-N-methyl-2-pyrrolidinone (CSz-NW) mixed solvent (1: 1, V/V) at mild conditions, room temperature and a normal atmosphere, took place using X-ray diffraction and TEM. The results show that the extract, basically free of ash and mainly between 80 and 240 ppm, is also a super-clean and superfine coal.
Study on reaction property of co-processing 00102295 bituminous coals and heavy oils Zou, G. and Wang, 2. Ranliao Huaxue Xuehuo, 1999, 27, (2). 187-191. (In Chinese) A resonance agitation reactor was used to study the reaction process of coprocessing two bituminous coals with low temperature coal tar distillate (LTCTD) and petroleum residue (PR) from Beijing Yanshan Petrochemical Corporation. The effects of temperature and types of heavy oils on coals conversion and products including preasphaltene, asphaltene were also investigated. When the reaction time was 60 minutes, the highest conversion was obtained at temperatures of 390” and 410” for Yangcun coal and Daliuta coal, respectively. The conversion followed the order of both LTCTD > blended heavy oils > PR. There was no intensive synergy between LTCTD and PR on coal conversion. GC-MS analysis showed that PR mainly consisted of long-chain alkane and LTCTD was mainly derivate of naphthalene. A discussion takes place on their interactions with coal,
00102290 Reduction of high-sulphur coal in the potassiumliquid ammonia system Kozlowski, M. Fuel, 1999, 78, (7), 769-774. Polish high-sulfur coal was twice subjected to reduction in the potassiumliquid ammonia system. The process was carried out on both raw and demineralized coal. Elemental and spectral analyses of the initial coal and the reduction products were performed. Different forms of sulfur found in the samples were studied by the classical chemical methods and by atmospheric pressure-temperature programmed reduction (AP-TPR).
00/02296 Sulfur forms in coal and desulfurization characteristics Sugawara, K. er al. Sozai Busseigoku Zasshi, 1998, II, (2), 88-101. (In Japanese) There are a number of areas reviewed in this paper, including the origin of sulfur and sulfur forms in coal, methods such as gravity separation that can be used for removing sulfur-rich materials, the presence and forms of organic sulfur and rapid pyrolysis of coal, which results in sulfur enrichment in certain products, such as semicoke. Greater than 90% of the organic
262
Fuel and Energy Abstracts
September
2000
07 Solid fuels (economics,
sulfur was removed from the subbituminous coal using this method. Sulfur in coal was derived mainly from: (1) parent plant material and (2) sulfate in seawater that overlaid peat swamps.
00102297 Technological and economic aspects of coal biodesulfurisation Klein, J. Biodegrada/ion, 1998. 9, (3-4), 293-300. Sulfur contained in coal is either part of the molecular coal structure (organically bound sulfur), is found in minerals such as pyrite (Fe&) or occurs in minor quantities in the form of sulfate and elemental sulfur. When pyrite crystals are finely distributed within the coal matrix, mechanical cleaning can only remove part of the pyrite. It can, however, be removed by microbial action requiring only mild conditions. The process involves simple equipment, almost no chemicals, but relatively long reaction times, and treatment of iron sulfate containing process water. Different process configurations are possible, depending on the coal particle size. Coal with particle sizes of less than 0.5 mm is preferably desulfurized in slurry reactors, while lump coal (>O.S mm) should be treated in heaps. Investment and operating costs are estimated for different process configurations on an industrial scale. Up to now there is no promising biochemical pathway for the degradation and/or desulfurization of organically bound sulfur in coal.
The effects of temperature, mixing and volatile OOlO2298 release on NO reduction mechanisms by coal reburning Yang, Y. B. er al. Sump. (In/.) Cornbust.. [Proc.], 1998. 2, 3009-3017. Using a 0.2-MW pilot-scale furnace an experimental investigation was carried out into the effects of temperature, devolatilization and mixing rates. The sensitivity of the reburning process to the devolatilization behaviour and mixing rates of the reburn coal was investigated using a mathematical model. The model considers the major NO reduction pathways relevant to reburn using a global chemical approach, namely, hydrocarbon fragments, volatile fuel-nitrogen species, and heterogeneous NO reduction by char particles. The experimental and predicted results both indicate that increased volatile yields and faster devolatilization rates can result in improved NO reduction in the reburn zone provided that the reburn zone is operated fuel rich so as to limit the consumption of volatile gases by oxygen. As reburn zone conditions become increasingly leaner, rapid coal pyrolysis results in the earlier consumption of volatile gases by oxygen as mixing takes place, leading to less NO reduction. Increasing the temperature increases the rate of coal devolatilization near the reburn coal injectors, leading to less efficient NO reduction. The magnitude of this effect was found to vary with the coal type. Consequently, while it is known that rank plays a vital role in determining the effectiveness of a coal as a reburn fuel, the results presented also show that simple rank indicators such as proximate volatile yield can only provide an initial indication of the suitability of a particular coal as a reburn fuel. Of further significance to the reburning process is the specific coal pyrolysis behaviour, which is controlled by the process temperature and heating rate and can vary between coals of similar rank but different morphology. The model predictions suggest that the NO reduction by CH fragments is the dominant NO-reduction mechanism in the reburn zone, accounting for about 70% of the total reduction observed.
Transport,
storage
00/02299 Association behaviors of coal-derived materials in organic solvents Iino, M. Prepr. Symp.-Am. Chew. Sot.. Div. Fuel Chem., 1999, 44, (I), 145-148. This review discusses the association behaviours of coal-derived materials in organic solvents. The factors under investigation include molecular weight, solubility, surface tension, viscosity and small angle neutron scattering. Comparisons are made with petroleum asphaltenes in solutions.
00102300 Coal transporters gain ground Fiscor, S. Coal Age, 2000, 105, (5). 24-39. In many ways, coal transportation cycles follow a pattern similar to that of the mining business itself. Both businesses are seasonal and both depend on each other as well as Mother Nature. The recent mergers and acquisitions that have taken place within the railroad industry have had enormous impact on the coal industry.
00102301 Cut costs by controlling dust Carter, R. A. Coral Age, 1999. 104. (l2), 19-20. Heavy haul-road dust can stir up haulage and maintenance problems. As the new generation of ultra-class haulers steadily filter into the industry’s truck fleets, operators are finding that the enormous payloads carried by these million-pound behemoths are accompanied by expanded maintenance requirements that include greater emphasis on road conditions and dust control.
business, marketing, policy)
00/02302 Economic plant producing transportation fuels and feed for carbon products from coal Simpson, T. B. Prepr. Symp.-Am. Chem Sot., D~v fwl Clam.. 1999. 44. (I), 966100. In this paper a discussion takes place on the economic feasibility of coal liquefaction for production of transportation fuels and pitch for carbon product production.
OOlO2363 Prevention of spontaneous combustion in coal stockpiles. Experimental results in coal storage yard Fierro, V. er (11.Fuel Process. Technol., 1999, 59. (I ), 23-34. The problem of coal stockpiles spontaneously igniting is serious both from an economic and a safety point of view. This paper deals with oxidation and spontaneous combustion of coal piles laid in coal storage yards and the measures to avoid the heat losses produced. Investigations on self-heating were carried out with five test piles (2000-3000 tons) built at the ENDESA power station in Teruel (Spain), and the results are here reported. The efficiency of several measures to reduce the heat losses were tested: periodic compaction, the use of a low angle slope, protection of the coal stockpiled with an artificial barrier and covering it with an ash-water slurry made with fly ash from the same power statjon. Wind tunnel tests were used to design the wind barrier which was showed to be effective although the best way to avoid the heat losses is the use of an ash-water slurry to cover the coal pile. A direct method to determine the coefficient of total losses was developed and the coefficients of heat losses and total losses were determined. The agreement between the temperatures measured by IR thermography and thermocouples leads to the conclusion that this technique is also able to accurately quantify heat emissions from coal piles,
00102304 The technology transfer Carter, R. A. Cocll Age, 2000, March, 32-3:;. This article presents a sampling from a steady stream of new materialhandling products that offer new options and alternatives for getting coal from one point to another.
Economics,
business,
marketing,
policy
00102305 Modeling demand for coal in India: vector autoregressive models with cointegrated variables Kulshreshtha, M. and Parikh, J. K. Energy, 2000, 25. (2). 1499168. In this paper, long-run structural relationships of coal demand with price and income variables have been estimated for the four major coal consuming sectors in India using annual time series data from 1970-1995. Some of the recent developments in multivariate dynamic econometric time series modelling techniques have been used, including the estimation of long-run co-integrating relationships, short-run dynamics and measurement of the effects of shocks and their effect on the evolution of dynamic coal demand system. The models have been estimated using co-integrating VAR framework, which allows for endogeneity of regressors. Results indicate that coal demand is likely to grow more than proportionately with economic growth due to high GDP elasticities and low price elasticities. Further, coal prices are found to be weakly exogenous in all the sectors except cement. Persistence profiles indicate that coal demand systems in the four sectors seem to be stable and converge to equilibrium within a period of around 47 years after a typical system-wide shock.
00102306 Organic petrological research on Rock-Eva1 pyrolysis parameters of coal from the Jurassic in Santanghu Basin, Xinjiang, Northwest China Huo, Y. er d.Berjing Drrrue Xuehuo, Zirun Kcruehun, 1998, 34, (6), 8Ol806. (In Chinese) With an aim of evaluating coal type, a series of the Jurassic coals in the Santanghu Basin has been studied by Rock-Eva1 pyrolysis, white microscopy, and element analysis. The results obtained by Rock-Eva1 pyrolysis are different from those by the other approaches. The influences, such as maceral composition, deposit-diagenetic environment and maturity, have been analysed, the conclusion is that high-content of hydrogen-rich maceral (4-19%) in the coals and the maturity are important effects on hydrogen index, H/C atomic ratio, and types of coal.
00102307 Tax credit synfuels influence coal markets Morey, M. Leshock, C. Cool Age, 2000, 105, (5) 35-36 The recent introduction of synthetic coal products has upset balance between supply and demand in the US coal market.
Fuel and Energy Abstracts
September
the fragile
2000
263
00/02285 Composition of carbonaceous deposits and catalyst deactivation in the early stages of the hydrocracking of a coal extract Begon, V. c/ ul. Fiircl, 1999, 7X, (6), 681-688. Carbonaceous deposits on finely dispersed MO& particulates and a NiMosupported catalyst, recovered from coal extract hydrocracking experiments, have been examined. Large surges in carbon deposition on catalyst surfaces were observed when using fresh catalyst and fresh feed. When using fresh feed with re-used catalyst, additional but smaller surges in deposition were found. The composition of the deposits appear to reflect, at least in part, the composition of the coal liquefaction extract. The relative stability in the amounts of carbonaceous deposit at reaction times longer than 2 h mirrors earlier findings suggesting that deactivation of the catalyst after the first 2 h of usage (up to 6 h) was marginal. Most of the deposition of carbonaceous material was found to precede completion of the activation (by sulfidation) of the catalysts. Moreover, much greater loadings of deposits were found on the finely dispersed sulfided-molybdenum catalyst compared with the supported NiMo/~-AlzO-i. Nevertheless, broadly comparable conversions of + 450°C boiling fractions have earlier been observed in the presence of the two catalysts, at reaction times longer than 30 min. Both these catalysts appear to function at their observed levels of activity, while carrying high levels of carbonaceous deposits. These findings tend to confirm earlier work suggesting that carbonaceous deposits might act as a permeable layer, and perhaps act as a reservoir of hydrogen-shuttling hydrogen from the liquid phase to molecules on the catalyst surface. 00102286 Development tendency of MDEA in desulfurization Wang, Q. and Huang, G. Gucmg~r~ng Huqong, 1999, I, 43-44, 47. (In Chinese) The absorption mechanism of MDEA is introduced to acidic gas in this review, the application of MDEA in desulfurization is also considered. 00/02287 Enhanced NO, reduction by interaction of nitrogen and sodium compounds in the reburning zone Zamansky, V. M. er nl. Symp. iInr./ Comhusf., /Proc./, 1998, 2, 3001-3008. This paper analyses the significant factors that affect NO, reduction performance in the advanced reburning-rich process (AR-Rich), which is a combination of reburning with a nitrogen agent and sodium carbonate injection into the reburning zone. These factors include the effects of chemical composition and stoichiometric ratio in the reburning zone, temperature of nitrogen-agent and sodium injections and the presence and concentration of sodium. Experiments in 30 and 300 kW combustors demonstrate that nitrogen oxide reduction is improved by injection of nitrogen-agents (urea or ammonia) in the reburning zone and can be further enhanced up to about 90% by small quantities of sodium carbonate (lo-15 ppm) added to aqueous nitrogen-agents. The delay from reburning fuel to nitrogen-agent injection affects the level of nitrogen oxide reduction. Sodium promoters broaden and deepen the temperature window of nitrogen oxide reduction with maximum values in the range of 1350-1550 K, allowing greater flexibility in installation. AR-Rich is dependent on mixing and droplet evaporation times, Performance is generally improved by longer mixing times. By using three kinetic codes and a detailed chemical mechanism, modelling helps in the interpretation of experimental results, including mixing regimes and provides insight into the internal chemical processes and reaction trends that govern the behaviour of this reacting system. During the selection of the injection nozzles, the predicted impacts of mixing provide some guidance. An identification of chemical reactions responsible for nitrogen-sodium interaction under fuel-rich conditions are also included. For experimental and modelling the results the observed trends seem to be very similar. 00102288 Investigation of desulfurization and sulfur analysis method in hydropyrolysis of coal Liu, L. CI al. Meircm Zhuunhrru, 1999, 22, (2), 39-42. (In Chinese) The desulfurization effect of hydropyrolysis was studied with two kinds of high sulfur coal. Suitable conditions are selected to analyse sulfur contents in raw coal, solid and liquid products using an elemental analyser. The results showed that high desulfurization obtained in hydropyrolysis desulfurization and sulfur distribution differed with each type of coal.
The effect of reduction on particular sulfur compounds is discussed. It was found that reduction in the potassium-liquid ammonia system led to cleavage of carbon-sulfur bonds, appearance of thiol groups, and the partial removal of pyrite and sulfates from the coal whereas the content of elemental sulfur did not change significantly. 00/02291 Removal of thiophene from benzene from coal source by liquid adsorption on modified ZSM-5 synthetic reolite Tan, X. and Wang, X. Chin. 1. Chem. Eng.. 1999, 7, (I), 91-94. The investigation presented is concerned with the removal of thiophene from benezene by adsorption on Cu- and La-exchanged ZSM-5 synthetic zeolite. 00/02292 Semi-industrial scale investigations into NO, emissions control using coal-over-coal reburn techniques Morgan, D. J. er al. Symp. (Inr.) Cornbust., [Proc.], 1998, 2. 304553051. In order to meet the present and future legislation for boiler emissions, the technique of reburning should be considered. Reburning also has the potential to provide NO, reduction with reasonable capital expenditure. The technique has not been applied extensively in new or retrofit applications and this may be because of the complexity of designing a new boiler or modifying an existing one and a scarcity of research information available to aid in this design. Other factors preventing the implementation of the reburning technique are the perceived problem of carbon burnout and the flame stability over a wide range of boiler operating conditions. Reburning has been demonstrated to be effective in a semiindustrial scale facility and the results confirm that the mechanism is suitable for retrofit application. NO, reductions greater than 77% were achieved, relative to a type-11 classification flame, when reburning high- and medium-volatile coal in various combinations. Overall, the most promising combinations for reburning were a low- or high-volatile coal as the primary fuel and a high-volatile, highly reactive coal as the reburn fuel. Typically, for effective NO, reduction, reburn fuel fractions greater than 10% were required in combination with a primary zone stoichiometry less than 0.9. Some features of chemical composition, structure 00102293 and reactive ability of Kansk-Achinsk lignite modified by ozone treatment Sharypov, V. I. er al. Fuel, 1999, 78. (6). 663-666. A study on the influence of ozonization of Kansk-Achinsk lignite on the chemical composition, structure and modified lignite reactivity in hydrogenation processes with different solvents and pyrite catalysts. The chemical analysis data indicates that the incorporation of oxygen into the organic matter of lignite occurs during ozonization. X-ray diffraction and electron paramagnetic resonance techniques were used to determine that ozonization causes the loosening of the lignite structure. Lignite modified by ozone treatment is more reactive, than untreated lignite, in hydrogenation reactions at 380-430°C in the presence of pyrite catalyst. 00102294 Study on enhancing desulfurization of coal by oxidizing coal selectively with Hz02 Liang, Y. et al. Meirun Zhuanhua, 1997, 20, (4). 80-85. (In Chinese) The Box-Wilson experimental procedure was used to study the preoxidization Illinois Basin coal (IBC-108) with HzOz and desulfurizing the pre-oxidized coal with formic acid. The pre-oxidation of coal with HzOz significantly enhanced the desulfurization of coal and that the removal of sulfur from the coal increased with the increasing amount of Hz02. Under the experimental conditions 500°C and 4.96-15.11 MPa) the maximum removal of 74.2% total sulfur and 73.3% organic sulfur was achieved, gaseous HzS was the main product. The mechanism of enhancing desulfurization of the coal by pre-oxidizing selectively with HzOz was also discussed.
00102289 Manufacturing clean coal by extraction with CS,-NMP mixed solvent Yuan, X. r( al. Meirun Zhuunhira. 1999. 22, (2) 53-55. (In Chinese) An analysis of an extract of Pangzhuang coal (Xuzhou), obtained by extraction with carbon-disulfide-N-methyl-2-pyrrolidinone (CSz-NW) mixed solvent (1: 1, V/V) at mild conditions, room temperature and a normal atmosphere, took place using X-ray diffraction and TEM. The results show that the extract, basically free of ash and mainly between 80 and 240 ppm, is also a super-clean and superfine coal.
Study on reaction property of co-processing 00102295 bituminous coals and heavy oils Zou, G. and Wang, 2. Ranliao Huaxue Xuehuo, 1999, 27, (2). 187-191. (In Chinese) A resonance agitation reactor was used to study the reaction process of coprocessing two bituminous coals with low temperature coal tar distillate (LTCTD) and petroleum residue (PR) from Beijing Yanshan Petrochemical Corporation. The effects of temperature and types of heavy oils on coals conversion and products including preasphaltene, asphaltene were also investigated. When the reaction time was 60 minutes, the highest conversion was obtained at temperatures of 390” and 410” for Yangcun coal and Daliuta coal, respectively. The conversion followed the order of both LTCTD > blended heavy oils > PR. There was no intensive synergy between LTCTD and PR on coal conversion. GC-MS analysis showed that PR mainly consisted of long-chain alkane and LTCTD was mainly derivate of naphthalene. A discussion takes place on their interactions with coal,
00102290 Reduction of high-sulphur coal in the potassiumliquid ammonia system Kozlowski, M. Fuel, 1999, 78, (7), 769-774. Polish high-sulfur coal was twice subjected to reduction in the potassiumliquid ammonia system. The process was carried out on both raw and demineralized coal. Elemental and spectral analyses of the initial coal and the reduction products were performed. Different forms of sulfur found in the samples were studied by the classical chemical methods and by atmospheric pressure-temperature programmed reduction (AP-TPR).
00/02296 Sulfur forms in coal and desulfurization characteristics Sugawara, K. er al. Sozai Busseigoku Zasshi, 1998, II, (2), 88-101. (In Japanese) There are a number of areas reviewed in this paper, including the origin of sulfur and sulfur forms in coal, methods such as gravity separation that can be used for removing sulfur-rich materials, the presence and forms of organic sulfur and rapid pyrolysis of coal, which results in sulfur enrichment in certain products, such as semicoke. Greater than 90% of the organic
262
Fuel and Energy Abstracts
September
2000
07 Solid fuels (economics,
sulfur was removed from the subbituminous coal using this method. Sulfur in coal was derived mainly from: (1) parent plant material and (2) sulfate in seawater that overlaid peat swamps.
00102297 Technological and economic aspects of coal biodesulfurisation Klein, J. Biodegrada/ion, 1998. 9, (3-4), 293-300. Sulfur contained in coal is either part of the molecular coal structure (organically bound sulfur), is found in minerals such as pyrite (Fe&) or occurs in minor quantities in the form of sulfate and elemental sulfur. When pyrite crystals are finely distributed within the coal matrix, mechanical cleaning can only remove part of the pyrite. It can, however, be removed by microbial action requiring only mild conditions. The process involves simple equipment, almost no chemicals, but relatively long reaction times, and treatment of iron sulfate containing process water. Different process configurations are possible, depending on the coal particle size. Coal with particle sizes of less than 0.5 mm is preferably desulfurized in slurry reactors, while lump coal (>O.S mm) should be treated in heaps. Investment and operating costs are estimated for different process configurations on an industrial scale. Up to now there is no promising biochemical pathway for the degradation and/or desulfurization of organically bound sulfur in coal.
The effects of temperature, mixing and volatile OOlO2298 release on NO reduction mechanisms by coal reburning Yang, Y. B. er al. Sump. (In/.) Cornbust.. [Proc.], 1998. 2, 3009-3017. Using a 0.2-MW pilot-scale furnace an experimental investigation was carried out into the effects of temperature, devolatilization and mixing rates. The sensitivity of the reburning process to the devolatilization behaviour and mixing rates of the reburn coal was investigated using a mathematical model. The model considers the major NO reduction pathways relevant to reburn using a global chemical approach, namely, hydrocarbon fragments, volatile fuel-nitrogen species, and heterogeneous NO reduction by char particles. The experimental and predicted results both indicate that increased volatile yields and faster devolatilization rates can result in improved NO reduction in the reburn zone provided that the reburn zone is operated fuel rich so as to limit the consumption of volatile gases by oxygen. As reburn zone conditions become increasingly leaner, rapid coal pyrolysis results in the earlier consumption of volatile gases by oxygen as mixing takes place, leading to less NO reduction. Increasing the temperature increases the rate of coal devolatilization near the reburn coal injectors, leading to less efficient NO reduction. The magnitude of this effect was found to vary with the coal type. Consequently, while it is known that rank plays a vital role in determining the effectiveness of a coal as a reburn fuel, the results presented also show that simple rank indicators such as proximate volatile yield can only provide an initial indication of the suitability of a particular coal as a reburn fuel. Of further significance to the reburning process is the specific coal pyrolysis behaviour, which is controlled by the process temperature and heating rate and can vary between coals of similar rank but different morphology. The model predictions suggest that the NO reduction by CH fragments is the dominant NO-reduction mechanism in the reburn zone, accounting for about 70% of the total reduction observed.
Transport,
storage
00/02299 Association behaviors of coal-derived materials in organic solvents Iino, M. Prepr. Symp.-Am. Chew. Sot.. Div. Fuel Chem., 1999, 44, (I), 145-148. This review discusses the association behaviours of coal-derived materials in organic solvents. The factors under investigation include molecular weight, solubility, surface tension, viscosity and small angle neutron scattering. Comparisons are made with petroleum asphaltenes in solutions.
00102300 Coal transporters gain ground Fiscor, S. Coal Age, 2000, 105, (5). 24-39. In many ways, coal transportation cycles follow a pattern similar to that of the mining business itself. Both businesses are seasonal and both depend on each other as well as Mother Nature. The recent mergers and acquisitions that have taken place within the railroad industry have had enormous impact on the coal industry.
00102301 Cut costs by controlling dust Carter, R. A. Coral Age, 1999. 104. (l2), 19-20. Heavy haul-road dust can stir up haulage and maintenance problems. As the new generation of ultra-class haulers steadily filter into the industry’s truck fleets, operators are finding that the enormous payloads carried by these million-pound behemoths are accompanied by expanded maintenance requirements that include greater emphasis on road conditions and dust control.
business, marketing, policy)
00/02302 Economic plant producing transportation fuels and feed for carbon products from coal Simpson, T. B. Prepr. Symp.-Am. Chem Sot., D~v fwl Clam.. 1999. 44. (I), 966100. In this paper a discussion takes place on the economic feasibility of coal liquefaction for production of transportation fuels and pitch for carbon product production.
OOlO2363 Prevention of spontaneous combustion in coal stockpiles. Experimental results in coal storage yard Fierro, V. er (11.Fuel Process. Technol., 1999, 59. (I ), 23-34. The problem of coal stockpiles spontaneously igniting is serious both from an economic and a safety point of view. This paper deals with oxidation and spontaneous combustion of coal piles laid in coal storage yards and the measures to avoid the heat losses produced. Investigations on self-heating were carried out with five test piles (2000-3000 tons) built at the ENDESA power station in Teruel (Spain), and the results are here reported. The efficiency of several measures to reduce the heat losses were tested: periodic compaction, the use of a low angle slope, protection of the coal stockpiled with an artificial barrier and covering it with an ash-water slurry made with fly ash from the same power statjon. Wind tunnel tests were used to design the wind barrier which was showed to be effective although the best way to avoid the heat losses is the use of an ash-water slurry to cover the coal pile. A direct method to determine the coefficient of total losses was developed and the coefficients of heat losses and total losses were determined. The agreement between the temperatures measured by IR thermography and thermocouples leads to the conclusion that this technique is also able to accurately quantify heat emissions from coal piles,
00102304 The technology transfer Carter, R. A. Cocll Age, 2000, March, 32-3:;. This article presents a sampling from a steady stream of new materialhandling products that offer new options and alternatives for getting coal from one point to another.
Economics,
business,
marketing,
policy
00102305 Modeling demand for coal in India: vector autoregressive models with cointegrated variables Kulshreshtha, M. and Parikh, J. K. Energy, 2000, 25. (2). 1499168. In this paper, long-run structural relationships of coal demand with price and income variables have been estimated for the four major coal consuming sectors in India using annual time series data from 1970-1995. Some of the recent developments in multivariate dynamic econometric time series modelling techniques have been used, including the estimation of long-run co-integrating relationships, short-run dynamics and measurement of the effects of shocks and their effect on the evolution of dynamic coal demand system. The models have been estimated using co-integrating VAR framework, which allows for endogeneity of regressors. Results indicate that coal demand is likely to grow more than proportionately with economic growth due to high GDP elasticities and low price elasticities. Further, coal prices are found to be weakly exogenous in all the sectors except cement. Persistence profiles indicate that coal demand systems in the four sectors seem to be stable and converge to equilibrium within a period of around 47 years after a typical system-wide shock.
00102306 Organic petrological research on Rock-Eva1 pyrolysis parameters of coal from the Jurassic in Santanghu Basin, Xinjiang, Northwest China Huo, Y. er d.Berjing Drrrue Xuehuo, Zirun Kcruehun, 1998, 34, (6), 8Ol806. (In Chinese) With an aim of evaluating coal type, a series of the Jurassic coals in the Santanghu Basin has been studied by Rock-Eva1 pyrolysis, white microscopy, and element analysis. The results obtained by Rock-Eva1 pyrolysis are different from those by the other approaches. The influences, such as maceral composition, deposit-diagenetic environment and maturity, have been analysed, the conclusion is that high-content of hydrogen-rich maceral (4-19%) in the coals and the maturity are important effects on hydrogen index, H/C atomic ratio, and types of coal.
00102307 Tax credit synfuels influence coal markets Morey, M. Leshock, C. Cool Age, 2000, 105, (5) 35-36 The recent introduction of synthetic coal products has upset balance between supply and demand in the US coal market.
Fuel and Energy Abstracts
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