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Low-cost potassium-containing char briquettes for NOx reduction
01 Solid fuels (derived solid fuels) The purpose of this paper is to describe the design of a process-flow model that will improve the understanding of the industrial energy use, efficiency, and pollution in the coke-making sector in the People's Republic of China (China). A modified version of the input-output process model (IOPM) developed by Lin and Polenske is used. By modifying the design of the IOPM model for use in the coke-making sector, three key contributions have been made. First, the end result of the design is a generic energy process-flow model that can be easily adapted for use in conducting energy and environmental analyses of cokemaking in China and other countries as well as examining other industrial processes in other sectors. Second, while constructing the design framework, the key differences in energy use and pollution generation among three generic coke-making technologies in China has been identified. Third, important issues have been determined, such as changes in iron and steel making technologies, plant location, and world coal and coke trade, that may affect the coke-making sector in China in the next decade. The research is a micro-level examination of the production processes and input-output structure of three alternative types of coke-making technologies (modified indigenous, small machinery, and non-recovery) in use in Shanxi Province, China, in the year 2000.
03/00490 Activated sludge fuels containing carbon and their manufacture Kaita, A. and Miyagawa, T. Jpn. Kokai Tokkyo Koho JP 2000 201,481 (CI. C10L5/46), 19 Jul 2002, Appl. 2000/400,274, 28 Dec. 2000. 9. (In Japanese) Carbon-containing fine-grain powder and activated sludge are kneaded with coal tar (binder) to give a solidified fuel. The coal tar used in the process is obtained by dry distillation of coal (1) at 250-450 ° under an atmosphere free of air or (2) at 250-600 ° under H or steam atmosphere. Thus manufactured fuel and such fuels containing tar binders mainly consisting of alcohols, naphthalene, carbolic oils, and/or glycerins are also claimed. Fuels showing high calorific value are manufactured from activated sludges.
03/00491 Characterization of chars obtained from co-pyrolysis of coal and petroleum residues Suelves, I. et al. Energy & Fuels, 2002, 16, (4), 878-886. Copyrolysis of coal and petroleum residue has been carried out in a bench scale unit in order to study the influence of the coal nature and the experimental conditions on the characteristics of the char obtained. Two coals of different rank, Samca (sub-bituminous) and Figaredo (bituminous), and a petroleum residue from the Maya crude have been used. Temperatures of 600, 650, and 700°C, pressures of 0.1, 0.5, and 1 MPa, and mass ratios (Coal/PR) of 70/30 and 50/50 have been studied. A synergistic effect on char yields, which increases as temperature, pressure, and PR/coal ratio increase, is observed for both coals studied. Some relevant char characteristics of sulfur content, reactivity, and coking properties have been analysed in order to detect a final use for the chars obtained. It is concluded that Samca/PR chars, especially for the 70/30 mixture, could be gasified to produce synthesis gas. Coal/PR ratio higher than 50/50, temperature lower than 700°C, and atmospheric pressure should be used in copyrolysis with Samca coal, to keep chars reactive enough to be gasified. Figaredo/PR chars, having a low sulfur content, good optical properties, and a lower reactivity could be used as a coke feedstock.
03100492 Coal blend rank changes and resultant coke quality from IHCC heat recovery cokemaking Valia, H. S. Ironmaking Conference Proceedings, 2002, (61), 419-426. The blend changes described in this paper encompassed a coal rank spectrum varying from high volatile (1.11% reflectance) to low volatile (1.42% reflectance). Such a blend rank change would have been impossible to imagine in a by-product coke battery. Despite the dramatic change in blend rank, the coke strength properties remained high, meeting the Ispat Inland contract specifications. Highlights of the relevant coal and coke relationships are discussed.
03100493 Combustion reactivity of char from pyrolysis of Shenmu macerals Sun, Q. et al. Huagong Xuebao, 2002, 53, (l), 92-95. (In Chinese) The combustion reactivity of'chars from pyrolysis of Shenmu coat maceral concentrations under different pyrolysis temperature, heating rate and pressure were systematically investigated by using TGA. The results indicated that the combustion reactivity of chars was related to pyrolysis temperature, pressure, heating rate and distribution of elements in chars. With decreasing temperature and pressure and increasing heating rate, the combustion reactivity of the pyrolysis residues increased. The lower the carbon content and higher the hydrogen content in chars, the higher combustion reactivity of chars. Under the same pyrolysis condition, the vitrinite chars had higher combustion reactivity that the fusinite chars.
03•00494 Design of coking charges based on optimization and prediction of coke strength according to chemical and petrographic indexes of coals Stankevieh, A. S. et al. Koks i Khimiya, 2002, (3), 9 17. (In Russian) A model for selection of coking charges and prediction of coke strength based on chemical and petrographic. Characteristics of coals (e.g. vitrinite reflectance, content of caking components, coal rank and petrographic composition fluctuations in the blend, oxidation state of coal, moisture content, ash content) was modified.
03•00495
Designed cellular coal
Rogers, D. and Plucinski, J. W. U.S. Pat. Appl. Publ. US 2002 92,229 (Cl. 44-530; C10L1/10), 18 Ju[ 2002, Appl. 733,602, 8 Dec 2000. 11. The invention relates to a coal-based cellular product that can be custom designed to have integral stiffeners or load paths, directed heat transfer paths, and/or directed mass transfer paths and methods for their production are described. Such design and production is made possible by the appropriate selection of starting materials, thermal treatment conditions and mold materials combined in at least some instances with segregation of different starting materials in different regions of a forming mold.
03100496 Eliminating coke formed in CH4 coupl.ing under plasma via pure H2 discharge in the system Cui, J. et al. Wu/i Huaxue Xuebao, 2002, 18, (3), 276-278. Eliminating coke under plasma with positive or negative high voltage in a DC electrical field has been compared with that in an AC field. The elimination of coke takes place only on the negative electrode in a DC field, while it does on both electrodes in an AC field. The coke on the reactor walls can be eliminated with either positive or negative high voltage and in either DC or AC fields. Based on the experimental facts, hypotheses on the reaction mechanism are suggested. The quantity of eliminated coke depends on the reactor and electrode arrangement, input power and electrode materials.
03100497 Enhancement role of additives in biomass coal briquette on sulfur fixing Lu, Y. et al. Huanjing Kexue, 2002, 23, (1), 26-29. (In Chinese) The sulfur-fixing performance of biomass coal briquette in a tubular furnace was studied. The effects of three additives A1203, Fe203, and MnOz on the sulfur retention by calcium-based sorbent in briquette were studied. The results showed that only AI203 displayed the enhancement of sulfur retention. The high temperature decomposition of CaSO4 in the reducing atmosphere was effectively inhibited with the addition of A1203. The XPS and XRD analyses of briquette ash showed that due to the interaction among A1203, CaSO4, and CaO, the composite CaSO4.3CaO.3AIzO3 with high thermal stability was formed, with its wrapping or binding onto the surface of CaSO4 crystal, the decomposition of CaSO4 was mitigated.
03/00498 Evolution of surface fractal dimension of coal chars during combustion Hu, S. et al. Ranliao Huaxue Xuebao, 2002, 30. (2). 136-140. (In Chinese) Non-linear dynamic character is shown on the chemical reaction and mass transfer of coal combustion. Fractal pore system changes with coal combustion. Surface transformation of coal partially reflects the change of inner-pore structure. Based on the fractal theory and the methods of image processing, the authors studied the SEM photographs of char samples of different types and different stages. It was shown that surface fractal dimension of coal char changes with two trends. There is a relation between coal samples and surface fractal dimension. By using least square method, the relation between surface fractal dimension and char conversion is obtained for different coal samples.
03/00499 Low-cost potassium-containing char briquettes for NOx reduction Bueno-Lopez, A. et al. Energy & Fuels, 2002, 16. (4). 997-1003. The activity of potassium-containing char briquettes, for NO,, reduction, has been investigated at 350°C, using a mixture of 0.2%NO/5%O2/Nz. The samples have been prepared from a Spanish bituminous coal and a coal tar-formaldehyde resin (resole) as binder. The influence of a number of variables relating to the preparation process, such potassium loading and pyrolysis temperature, on their reduction capacity has been analysed. For comparative purposes, a set of binder-free samples with different potassium contents has been prepared. Potassium contents highly affect the selectively of the briquettes. Samples prepared with high potassium loading exhibit satisfactory selectivity values with very low burnoff. Lifetime tests, until complete consumption of the sample, have been performed with the samples exhibiting high selectivity values. The most important finding is that high selectivity values are maintained during the whole life of
Fuel and Energy Abstracts
March 2003 71
01 Solid fuels (derived solid fuels) the briquette. The binder affects the reaction kinetic and the lifetime of the sample. A binder-free sample presents higher activity with regard to binder samples.
03/00500 furnace
Manufacture of powdered coal for blowing into
Okochi, I. et al. Jpn. Kokai Tokkyo Koho JP 2000 194,408 (CI. C21B5/00), 10 Jul 2002, Appl. 2000/400,638, 28 Dec 2000. 13. (In Japanese) A finely powdered coal is manufactured for blowing into and combustion in a furnace, e.g. blast furnace. Control of particle size distribution of finely powdered coal is conducted by using grindability of the starting material coal as a parameter and adjusting the powdering force applied to the starting material coal in a grinding apparatus. No adhesion or clogging occurs in the process of blowing the powder through pipes.
03/00501
Nuclear microprobe analysis of artificial coal
Bailey, A. M. et al. Nuclear Instruments & Method~ in Physics Research, Section B: Beam Interactions with Materials and Atoms, 2002, (189), 418~20. An artificially coalified Taxodium peat was used to examine the behaviour of inorganic constituents in terrestrial organic matter during the early coalification process. The artificial coal is produced by subjecting the peat to incremental increases in temperature up to 60 ° and pressures to 14.48 MPa over a 4-week period in a partially open reactor. A standard polished thin section 30 gm thick is then cut from the resulting disk and examined using light microscopy to select and mark areas to be cut from the polished thin section. The distribution of inorganic constituents in these areas of the solid produced during the coalification process is then studied using nuclear microscopy. Results suggest tll'at concentrations of inorganic constituents, including silicon, are lower in the newly produced solids than in the initial material. Distributions of other inorganic elements, including aluminium, sulfur, chlorine, potassium, calcium, barium and iron are also investigated.
03/00502 Petrochemical coke combustion and catalytic reaction mechanism Xu, M. et al. Huadong Ligong Daxue Xueb~u~, 2002, 28, (1), 12-15. (In Chinese) The effect of different types of ionic combustion-supporting agents on petrochemical coke combustion was studied by detecting combustion ratios. Comparing with coal combustion process, coke catalytic combustion rule and mechanism were clarified. Transition metal ionic catalysts' catalytic function on coke combustion can be interpreted with oxygen-transfer mechanism. IA ionic catalyst has excellent catalytic function and is the most suitable catalyst in petrochemical coke combustion. IA and IIA ionic catalysts' catalytic function on coke combustion can be interpreted by the process of producing C + which is easier to ignite.
03/00503 Research on BP neural network in the prediction model of optimized coal blending Ying, L. and Zhou, J. Meitaa Zhuanhua, 2002, 25, (2), 79 85. (In Chinese) Due to the variability of coal properties, coal blending is an optimization procedure under uncertain circumstances. The traditional linear programming models can not solve this non-linear problem. However, BP neural network, an effective tool for non-linear optimization, was successfully applied in prediction of blended coal's properties. Different BP network structures and factors affecting its performance are analysed. It shows that the number of learning samples is the key for a good performance of BP network.
03•00504 Simultaneous co-carbonization of coal and decant oil: the effect of varying process parameters Badger, M. et al. Preprints o f Symposia -- American Chemical Society, Division o f Fuel Chemistry, 2002, 47, (1), 179-180. There are efforts to scale up the co-coking process from static small laboratory-scale tubing bomb experiments to a semi-continuous small pilot-scale delayed coker unit. As a result, some changes in the processing parameters are expected, which could have an effect on the yield and composition of products. Changing the experimental parameters can have a marked effect on the quality and yield of the products produced in the co-coking of coat and decant oil. While increasing the quantity of coal in the feed mix does not seem to have a detrimental effect, lowering the water feed rate results in a coke product of poor quality if used as a value-added carbon. Increasing the drum pressure was found to have a disproportionate effect. The yield of the liquid increases with increasing pressure, along with the yield of low boiling liquids. Conversely, the high degree of isotropic carbon reduces the quality of the coke.
72
Fuel and Energy Abstracts
March 2003
03/00505 boron
Structure of coke powder heat-treated with
Hamada, T. et aL Carbon, 2002, 40, (8), 1203-1210. Coal tar pitch-based coke powder with a fine mosaic texture was heattreated with various concentrations of boron powder at 2900°C. Increasing the boron amount led to smaller d002 and larger dll0, and made the original fine texture coarser. Some small particles showed specific structures of polyhedrons, of which surfaces are 002 planes of graphite lattice, after heat treatment with boron. The size of the polyhedron increased with boron content. Boron concentration was lower at the surface than at the inner portions of particles for a powder heat-treated with a higher amount of boron, while it depended less on the depth for that heat-treated with a lower amount of boron. The formation mechanism of the polyhedron particle is discussed.
03100506 Study on structural properties and their influencing factors during gasification of chars Xiang, Y. et al. Ranliao Huaxue aVuebao, 2002, 30, (2), 108-112. (In Chinese) This work considers the development of porosity in chars prepared at different conditions by measuring their N2 adsorption characteristics. It is found that the structural properties are affected not only by original char properties, but also by gasification conditions (reactant gas and temperature). The order of the specific surface area and pore volume is Binxian char > Shenmu char > Wangfeng char at the same carbon conversion. High gasification temperature would result in lower specific surface area and micropore area. The results obtained also show that carbon dioxide produces micropores during the whole gasification process; it produces more micropores than steam during high carbon conversion. The specific surface area and micropore area of demineralized chars are larger than those of raw coal chars during initial stage, but opposite results are obtained during high carbon conversion.
03/00507 Study on the effect of microwave on the dewatering of fine coal Cui, P. et al. Ranliao Huaxue Xuebao, 2002, 30, (2), 178-181. (In Chinese) The coal-water slurry with different concentrations was prepared using four different kinds of coal (gas coal, fat coal, coking coal and lean coal) and dewatered using microwave. The effect of coal particle, rank, strength and irradiation time of microwave on the moisture content of the filter cake was investigated. In addition, the dewatering efficiency was compared using microwave and electronic heat under same power and time. The results show that the moisture content of the coal cake depends on the particle size and coal rank. The fine coal has higher water content in its cake. With increasing coal rank, the moisture content in the cake decrease and then increase and the coking coal cake has the lowest value. With increasing irradiation time, the water content of the cake with different rank and particle size tends to be the same. The water content in the cake decreases with the enhancement of the microwave strength, but has no effect on the relation between the water content and the granularity. Compared with electronic heating, microwave decrease the dewatering time, therefore, decreasing energy consumption and improving efficiency.
03/00508 Study on hydropyrolysis of macerals from Shenmu coal Sun, Q. et al. Ranliao Huaxue Xuebao, 2002, 30, (l), 11-15. (in Chinese) Hydropyrolysis of maceral concentrates from Shenmu coal was investigated by using TGA at a heating rate of 20°C/min to 900°C final temperature at 0.1-3 MPa. The effect of pressure on the TG/DTG curve, distribution of elements in solid residues and removal of sulfur and nitrogen were investigated. A remarkable weight loss occurred in the temperature range 378-718°C, the peak temperature of the maximum reaction rate was 496 and 522°C for V-C and F-C, respectively, and a larger weight loss rate for V-C was observed. With increasing pressure the diffusion of hydrogen increased markedly, which led to increase of weight loss. The C content of the solid residue increased, H and O content decreased, and S content changed little. The desulfurization and denitrogenation also increased with increase in pressure. At a pressure of 3 MPa, V-C desulfurization was higher than that of F-C. With increasing pyrolysis pressure, the combustion reactivity of solid residue first decreased and then increased. Combustion reactivity of the V-C solid residue was higher than that of the F-C residue under the same conditions.
03/00490 Activated sludge fuels containing carbon and their manufacture Kaita, A. and Miyagawa, T. Jpn. Kokai Tokkyo Koho JP 2000 201,481 (CI. C10L5/46), 19 Jul 2002, Appl. 2000/400,274, 28 Dec. 2000. 9. (In Japanese) Carbon-containing fine-grain powder and activated sludge are kneaded with coal tar (binder) to give a solidified fuel. The coal tar used in the process is obtained by dry distillation of coal (1) at 250-450 ° under an atmosphere free of air or (2) at 250-600 ° under H or steam atmosphere. Thus manufactured fuel and such fuels containing tar binders mainly consisting of alcohols, naphthalene, carbolic oils, and/or glycerins are also claimed. Fuels showing high calorific value are manufactured from activated sludges.
03/00491 Characterization of chars obtained from co-pyrolysis of coal and petroleum residues Suelves, I. et al. Energy & Fuels, 2002, 16, (4), 878-886. Copyrolysis of coal and petroleum residue has been carried out in a bench scale unit in order to study the influence of the coal nature and the experimental conditions on the characteristics of the char obtained. Two coals of different rank, Samca (sub-bituminous) and Figaredo (bituminous), and a petroleum residue from the Maya crude have been used. Temperatures of 600, 650, and 700°C, pressures of 0.1, 0.5, and 1 MPa, and mass ratios (Coal/PR) of 70/30 and 50/50 have been studied. A synergistic effect on char yields, which increases as temperature, pressure, and PR/coal ratio increase, is observed for both coals studied. Some relevant char characteristics of sulfur content, reactivity, and coking properties have been analysed in order to detect a final use for the chars obtained. It is concluded that Samca/PR chars, especially for the 70/30 mixture, could be gasified to produce synthesis gas. Coal/PR ratio higher than 50/50, temperature lower than 700°C, and atmospheric pressure should be used in copyrolysis with Samca coal, to keep chars reactive enough to be gasified. Figaredo/PR chars, having a low sulfur content, good optical properties, and a lower reactivity could be used as a coke feedstock.
03100492 Coal blend rank changes and resultant coke quality from IHCC heat recovery cokemaking Valia, H. S. Ironmaking Conference Proceedings, 2002, (61), 419-426. The blend changes described in this paper encompassed a coal rank spectrum varying from high volatile (1.11% reflectance) to low volatile (1.42% reflectance). Such a blend rank change would have been impossible to imagine in a by-product coke battery. Despite the dramatic change in blend rank, the coke strength properties remained high, meeting the Ispat Inland contract specifications. Highlights of the relevant coal and coke relationships are discussed.
03100493 Combustion reactivity of char from pyrolysis of Shenmu macerals Sun, Q. et al. Huagong Xuebao, 2002, 53, (l), 92-95. (In Chinese) The combustion reactivity of'chars from pyrolysis of Shenmu coat maceral concentrations under different pyrolysis temperature, heating rate and pressure were systematically investigated by using TGA. The results indicated that the combustion reactivity of chars was related to pyrolysis temperature, pressure, heating rate and distribution of elements in chars. With decreasing temperature and pressure and increasing heating rate, the combustion reactivity of the pyrolysis residues increased. The lower the carbon content and higher the hydrogen content in chars, the higher combustion reactivity of chars. Under the same pyrolysis condition, the vitrinite chars had higher combustion reactivity that the fusinite chars.
03•00494 Design of coking charges based on optimization and prediction of coke strength according to chemical and petrographic indexes of coals Stankevieh, A. S. et al. Koks i Khimiya, 2002, (3), 9 17. (In Russian) A model for selection of coking charges and prediction of coke strength based on chemical and petrographic. Characteristics of coals (e.g. vitrinite reflectance, content of caking components, coal rank and petrographic composition fluctuations in the blend, oxidation state of coal, moisture content, ash content) was modified.
03•00495
Designed cellular coal
Rogers, D. and Plucinski, J. W. U.S. Pat. Appl. Publ. US 2002 92,229 (Cl. 44-530; C10L1/10), 18 Ju[ 2002, Appl. 733,602, 8 Dec 2000. 11. The invention relates to a coal-based cellular product that can be custom designed to have integral stiffeners or load paths, directed heat transfer paths, and/or directed mass transfer paths and methods for their production are described. Such design and production is made possible by the appropriate selection of starting materials, thermal treatment conditions and mold materials combined in at least some instances with segregation of different starting materials in different regions of a forming mold.
03100496 Eliminating coke formed in CH4 coupl.ing under plasma via pure H2 discharge in the system Cui, J. et al. Wu/i Huaxue Xuebao, 2002, 18, (3), 276-278. Eliminating coke under plasma with positive or negative high voltage in a DC electrical field has been compared with that in an AC field. The elimination of coke takes place only on the negative electrode in a DC field, while it does on both electrodes in an AC field. The coke on the reactor walls can be eliminated with either positive or negative high voltage and in either DC or AC fields. Based on the experimental facts, hypotheses on the reaction mechanism are suggested. The quantity of eliminated coke depends on the reactor and electrode arrangement, input power and electrode materials.
03100497 Enhancement role of additives in biomass coal briquette on sulfur fixing Lu, Y. et al. Huanjing Kexue, 2002, 23, (1), 26-29. (In Chinese) The sulfur-fixing performance of biomass coal briquette in a tubular furnace was studied. The effects of three additives A1203, Fe203, and MnOz on the sulfur retention by calcium-based sorbent in briquette were studied. The results showed that only AI203 displayed the enhancement of sulfur retention. The high temperature decomposition of CaSO4 in the reducing atmosphere was effectively inhibited with the addition of A1203. The XPS and XRD analyses of briquette ash showed that due to the interaction among A1203, CaSO4, and CaO, the composite CaSO4.3CaO.3AIzO3 with high thermal stability was formed, with its wrapping or binding onto the surface of CaSO4 crystal, the decomposition of CaSO4 was mitigated.
03/00498 Evolution of surface fractal dimension of coal chars during combustion Hu, S. et al. Ranliao Huaxue Xuebao, 2002, 30. (2). 136-140. (In Chinese) Non-linear dynamic character is shown on the chemical reaction and mass transfer of coal combustion. Fractal pore system changes with coal combustion. Surface transformation of coal partially reflects the change of inner-pore structure. Based on the fractal theory and the methods of image processing, the authors studied the SEM photographs of char samples of different types and different stages. It was shown that surface fractal dimension of coal char changes with two trends. There is a relation between coal samples and surface fractal dimension. By using least square method, the relation between surface fractal dimension and char conversion is obtained for different coal samples.
03/00499 Low-cost potassium-containing char briquettes for NOx reduction Bueno-Lopez, A. et al. Energy & Fuels, 2002, 16. (4). 997-1003. The activity of potassium-containing char briquettes, for NO,, reduction, has been investigated at 350°C, using a mixture of 0.2%NO/5%O2/Nz. The samples have been prepared from a Spanish bituminous coal and a coal tar-formaldehyde resin (resole) as binder. The influence of a number of variables relating to the preparation process, such potassium loading and pyrolysis temperature, on their reduction capacity has been analysed. For comparative purposes, a set of binder-free samples with different potassium contents has been prepared. Potassium contents highly affect the selectively of the briquettes. Samples prepared with high potassium loading exhibit satisfactory selectivity values with very low burnoff. Lifetime tests, until complete consumption of the sample, have been performed with the samples exhibiting high selectivity values. The most important finding is that high selectivity values are maintained during the whole life of
Fuel and Energy Abstracts
March 2003 71
01 Solid fuels (derived solid fuels) the briquette. The binder affects the reaction kinetic and the lifetime of the sample. A binder-free sample presents higher activity with regard to binder samples.
03/00500 furnace
Manufacture of powdered coal for blowing into
Okochi, I. et al. Jpn. Kokai Tokkyo Koho JP 2000 194,408 (CI. C21B5/00), 10 Jul 2002, Appl. 2000/400,638, 28 Dec 2000. 13. (In Japanese) A finely powdered coal is manufactured for blowing into and combustion in a furnace, e.g. blast furnace. Control of particle size distribution of finely powdered coal is conducted by using grindability of the starting material coal as a parameter and adjusting the powdering force applied to the starting material coal in a grinding apparatus. No adhesion or clogging occurs in the process of blowing the powder through pipes.
03/00501
Nuclear microprobe analysis of artificial coal
Bailey, A. M. et al. Nuclear Instruments & Method~ in Physics Research, Section B: Beam Interactions with Materials and Atoms, 2002, (189), 418~20. An artificially coalified Taxodium peat was used to examine the behaviour of inorganic constituents in terrestrial organic matter during the early coalification process. The artificial coal is produced by subjecting the peat to incremental increases in temperature up to 60 ° and pressures to 14.48 MPa over a 4-week period in a partially open reactor. A standard polished thin section 30 gm thick is then cut from the resulting disk and examined using light microscopy to select and mark areas to be cut from the polished thin section. The distribution of inorganic constituents in these areas of the solid produced during the coalification process is then studied using nuclear microscopy. Results suggest tll'at concentrations of inorganic constituents, including silicon, are lower in the newly produced solids than in the initial material. Distributions of other inorganic elements, including aluminium, sulfur, chlorine, potassium, calcium, barium and iron are also investigated.
03/00502 Petrochemical coke combustion and catalytic reaction mechanism Xu, M. et al. Huadong Ligong Daxue Xueb~u~, 2002, 28, (1), 12-15. (In Chinese) The effect of different types of ionic combustion-supporting agents on petrochemical coke combustion was studied by detecting combustion ratios. Comparing with coal combustion process, coke catalytic combustion rule and mechanism were clarified. Transition metal ionic catalysts' catalytic function on coke combustion can be interpreted with oxygen-transfer mechanism. IA ionic catalyst has excellent catalytic function and is the most suitable catalyst in petrochemical coke combustion. IA and IIA ionic catalysts' catalytic function on coke combustion can be interpreted by the process of producing C + which is easier to ignite.
03/00503 Research on BP neural network in the prediction model of optimized coal blending Ying, L. and Zhou, J. Meitaa Zhuanhua, 2002, 25, (2), 79 85. (In Chinese) Due to the variability of coal properties, coal blending is an optimization procedure under uncertain circumstances. The traditional linear programming models can not solve this non-linear problem. However, BP neural network, an effective tool for non-linear optimization, was successfully applied in prediction of blended coal's properties. Different BP network structures and factors affecting its performance are analysed. It shows that the number of learning samples is the key for a good performance of BP network.
03•00504 Simultaneous co-carbonization of coal and decant oil: the effect of varying process parameters Badger, M. et al. Preprints o f Symposia -- American Chemical Society, Division o f Fuel Chemistry, 2002, 47, (1), 179-180. There are efforts to scale up the co-coking process from static small laboratory-scale tubing bomb experiments to a semi-continuous small pilot-scale delayed coker unit. As a result, some changes in the processing parameters are expected, which could have an effect on the yield and composition of products. Changing the experimental parameters can have a marked effect on the quality and yield of the products produced in the co-coking of coat and decant oil. While increasing the quantity of coal in the feed mix does not seem to have a detrimental effect, lowering the water feed rate results in a coke product of poor quality if used as a value-added carbon. Increasing the drum pressure was found to have a disproportionate effect. The yield of the liquid increases with increasing pressure, along with the yield of low boiling liquids. Conversely, the high degree of isotropic carbon reduces the quality of the coke.
72
Fuel and Energy Abstracts
March 2003
03/00505 boron
Structure of coke powder heat-treated with
Hamada, T. et aL Carbon, 2002, 40, (8), 1203-1210. Coal tar pitch-based coke powder with a fine mosaic texture was heattreated with various concentrations of boron powder at 2900°C. Increasing the boron amount led to smaller d002 and larger dll0, and made the original fine texture coarser. Some small particles showed specific structures of polyhedrons, of which surfaces are 002 planes of graphite lattice, after heat treatment with boron. The size of the polyhedron increased with boron content. Boron concentration was lower at the surface than at the inner portions of particles for a powder heat-treated with a higher amount of boron, while it depended less on the depth for that heat-treated with a lower amount of boron. The formation mechanism of the polyhedron particle is discussed.
03100506 Study on structural properties and their influencing factors during gasification of chars Xiang, Y. et al. Ranliao Huaxue aVuebao, 2002, 30, (2), 108-112. (In Chinese) This work considers the development of porosity in chars prepared at different conditions by measuring their N2 adsorption characteristics. It is found that the structural properties are affected not only by original char properties, but also by gasification conditions (reactant gas and temperature). The order of the specific surface area and pore volume is Binxian char > Shenmu char > Wangfeng char at the same carbon conversion. High gasification temperature would result in lower specific surface area and micropore area. The results obtained also show that carbon dioxide produces micropores during the whole gasification process; it produces more micropores than steam during high carbon conversion. The specific surface area and micropore area of demineralized chars are larger than those of raw coal chars during initial stage, but opposite results are obtained during high carbon conversion.
03/00507 Study on the effect of microwave on the dewatering of fine coal Cui, P. et al. Ranliao Huaxue Xuebao, 2002, 30, (2), 178-181. (In Chinese) The coal-water slurry with different concentrations was prepared using four different kinds of coal (gas coal, fat coal, coking coal and lean coal) and dewatered using microwave. The effect of coal particle, rank, strength and irradiation time of microwave on the moisture content of the filter cake was investigated. In addition, the dewatering efficiency was compared using microwave and electronic heat under same power and time. The results show that the moisture content of the coal cake depends on the particle size and coal rank. The fine coal has higher water content in its cake. With increasing coal rank, the moisture content in the cake decrease and then increase and the coking coal cake has the lowest value. With increasing irradiation time, the water content of the cake with different rank and particle size tends to be the same. The water content in the cake decreases with the enhancement of the microwave strength, but has no effect on the relation between the water content and the granularity. Compared with electronic heating, microwave decrease the dewatering time, therefore, decreasing energy consumption and improving efficiency.
03/00508 Study on hydropyrolysis of macerals from Shenmu coal Sun, Q. et al. Ranliao Huaxue Xuebao, 2002, 30, (l), 11-15. (in Chinese) Hydropyrolysis of maceral concentrates from Shenmu coal was investigated by using TGA at a heating rate of 20°C/min to 900°C final temperature at 0.1-3 MPa. The effect of pressure on the TG/DTG curve, distribution of elements in solid residues and removal of sulfur and nitrogen were investigated. A remarkable weight loss occurred in the temperature range 378-718°C, the peak temperature of the maximum reaction rate was 496 and 522°C for V-C and F-C, respectively, and a larger weight loss rate for V-C was observed. With increasing pressure the diffusion of hydrogen increased markedly, which led to increase of weight loss. The C content of the solid residue increased, H and O content decreased, and S content changed little. The desulfurization and denitrogenation also increased with increase in pressure. At a pressure of 3 MPa, V-C desulfurization was higher than that of F-C. With increasing pyrolysis pressure, the combustion reactivity of solid residue first decreased and then increased. Combustion reactivity of the V-C solid residue was higher than that of the F-C residue under the same conditions.