- Email: [email protected]
00963 Research on production of high quality foundry coke in 75-type non-recoverable double-coke oven
01
Solid fuels (preparation)
capture activity at low temperature. During coal gasification at high temperature, iron played a role as sulfur-transfer in the desulfurization. Calcium-iron complex desulfurizers increased sulfur capture efficiency. The sulfur capture efficiency was affected by the ratio of iron to sulfur and calcium to sulfur. CO2 acted to suppress in-situ sulfur capture and Fe& decomposition and changed greatly the crystallized state of products.
Integrated technique for pyritic sulfur reduction in 99100952 Indian (Assam) coal Bhatnagar, A. et al. Energy Convers. Manage., 1998, 39, (11). 1121-1126. Using a pyrite oxidizing organism such as Thiobacillus ferrooxidans, microbial desulfurization of coal results in approximately 90% pyritic sulfur reduction in 30 density. An integrated technique, comprised of bacterial preconditioning and subsequent oil agglomeration, is concerned with surface modification of the pyrite by short contacts (2-240 min) with a culture of Thiobacillus ferrooxidans and its rejection during agglomeration. Coal (-250 pm) was preconditioned with the bacterial culture for 2.5-30 min before subjecting it to oil agglomeration. About 75-80% ash rejection and 90-97% pyritic sulfur reduction (PSRD) have been obtained. Extending preconditioning for 240 min could not improve the PSRD beyond 97%. By increasing the particle size from -250 pm to -800 + 400 Frn the PSRD decreased from 97% to 71%, whereas prolonging the preconditioning period to 240 min enhanced the PSRD to 90%. The integrated technique has considerably reduced the time requirement from 20-30 density to 30-240 min in order to obtain 90% pyritic sulfur reduction. Compared to traditionally used petroleum fractions, castor oil has been used as the agglomerant and found to be a good substitute.
Manufacture of needle coke 99100953 Shibata, K. et al. Jpn. Kokai Tokkyo Koho JP 10 168,461 [98 168,461] (Cl. ClOC3/02), 23 Jun 1998, Appl. 96/334,157, 13 Dee 1996, 5 pp. (In Japanese) High-quality needle coke can be manufactured by using coal tar raw material generated by adding recycle coal tar or coal-tar pitch to coal charge in a coke oven. The coal tar raw material contains 6-10 wt% phenanthrene. The needle coke manufactured can be used as graphite electrode. Method for increasing the charring ratio of coal 99100954 Cho, M. Y. et al. PCT Int. Appl. WO 98 28,385 (Cl. ClOL9/10), 2 Jul 1998, KR Appl. 9,673,769, 27 Dee 1996, 20 pp. A method for increasing the charring ratio of coal is discussed. An iron ingot using coal, magnesium oxide or limestone is used in manufacturing as an additive for charring coal. The additive increases the charring ratio of the coal without affecting the slag. Coal is mixed with an MgO suspension or limestone suspension. The mixture is dried to attach MgO or the limestone onto the surface of the coal. The charring effect is increased and hence the amount of coke used can be reduced. Numerical modeling of waste heat recovery boiler 99100955 Meyyappan, M. et al. Heat Mass Transfer Australas. 1996, Proc. Conf., 6th, C. 1996, (Pub. 1998) 303-311. Edited by Leonardi, E. and Madhusudana, V., Bengell House, New York. As a part of a consulting study undertaken by the Cooperative Center for New Technologies for Power Generation from Low-Rank Coal (CRC), a waste heat recovery boiler utilizing plant off-gas was numerically modelled, using the code CFDSFLOW3D (1994). The principal aim of the work was to estimate temperatures of char and the dust within the boiler to determine the likelihood of deposition onto the boiler walls. A series of solution strategies were adopted to overcome the difficulties in achieving convergence for this problem which were due to its complex shape and multiple blocking. Two areas were covered - the results of simulating operation in which only plant off-gas and char are combusted (Mode 1) and operation in which natural gas and melter gas are injected (Mode 3). For Mode 1 the model predicted good mixing in the region between the primary and secondary air jets and a nearly 100% char burnout. Most of the char and primary concentrate particles hitting the walls are cooler than the respectively critical temperatures identified for sticking at the boiler walls. Based on Flamelet modelling, combustion essentially takes place at and below the primary air jet plane. For Mode 3, the maximum temperature predicted agrees with the expected maximum adiabatic temperature for the natural gas combustion. Procedure for separation of ballast particles of coal 99100956 Kahnt, G. et al. Ger. Offen., DE 19,700,471 (Cl. ClOL5/04), 16 Jul 1998, Appl. 19,700,471, 9 Jan 1997, 8 pp. (In German) This paper discusses the four stages which are involved in a simple separation of ballast particles of coal, brown coal in particular. Stage 1 - a classification to obtain a fraction of 510 mm diameter (preferably <6 mm diameter). Stage 2 - drying at 105-125” to a predetermined moisture content (e.g. 520%). Stage 3 - charging into a horizontal air stream having a predetermined flow rate from a port located above the air stream. Stage 4 - removal of the ballast particles to withdrawal positions located below the air stream in relation to the particle mass and flow rate.
102
Fuel and Energy Abstracts
March 1999
99100957 Progress and energy effects of weathering and degassing of solid fuels Postrzednik, S. Energy Convers. Manage., 1998. 39, (16-18). 1883-1889. Low temperature oxidation of solid fuels is the main phenomenon of weathering and self heating of the combustible substance. Additionally, the degassing and low temperature devolatilization of the solid fuel and the transport of water vapour through the solid fuel bed are of importance. In this paper, energy losses and the ecological aspects of solid fuel weathering (self heating, endogenous fires, gas explosions) are discussed. A method of the energy consumption determination in the weathering process of solid fuel, treated as a physical and chemical process, by using the kinetic relations of the main phenomena is proposed. 99100956 Pyrolysis of coal in a fluidized bed reactor I. Effect of temperature on the devolatilization Li, H. et al. Ranliao Huaxue Xuebao, 1998, 26, (3). 238-242. (In Chinese) A specially designed fluidized-bed reactor (I.D. 48 mm) and a cone-shaped distributor were used to pyrolyse Shenmu coal (-45+80 mesh). The relationship between the gas-phase product yield and the dense-phase temperature was derived. While the yields of HZ, CO, CHI and CzH4 increased dramatically with increasing dense-phase temperature, the liquid yield reaches the maximum at a dense-phase temperature of 600-650°C. When the freeboard temperature is high, coal volatiles can undergo significant secondary reactions even at a very short residence time. The results were believed to represent a more accurate trend of the effect of bed temperature on gas-phase product yield because secondary reactions in the vapour phase were minimized. Pyrolysis of coal in fluidized bed reactors 99100959 Li, H. et al. Meitan Zhuanhua, 1997, 20, (4). 9-14. (In Chinese) The pyrolysis of coal in fluidized bed reactors is discussed with emphases apparatus, equipment and affecting factors.
on
99100960 Pyrolysis of coal with hydrogen-rich gases. 2. Desulfurization and denitrogenation in coal pyrolysis under coke-oven gas and synthesis gas Liao, H. et al. Fuel, 1998, 77, (14), 1643-1646. Desulfurization and denitrogenation were investigated by analysing the chars and tars from pyrolysis of high sulfur Chinese Yanzhou bituminous coal with coke-oven gas (COG), synthesis gas (SG), Ha and Nz at different operating conditions. It is found that desulfurization and denitrogenation in coal pyrolysis with COG, SG and Hz are about 20% and IO-20% higher than those under Nz, respectively. At the same hydrogen partial pressure, desulfurization under COG (5 MPa) is about 4.5% higher than that under Hz (3 MPa), while the denitrogenation is about 3.5% lower. 99100961 Rapid operation of beneficiation plants with respect to the ash content factor of run-of-mine coals Fon, M. G. et al. Koks K&m., 1998, (4), 4-5. (In Russian) The reliability of the prediction of the theoretical balance of coal beneficiation products in preparation plants, the determination of the fractional composition of coals from their ash content and the ash content as a determining factor of classification parameters are the focus of this work. 99100962 Reducing fouling from brown coals by sodiumbinding additives Vuthaluru, H. B. ef al. Fuel Process. Technol., 1998, 55, (2), 161-173. The methods to control medium-temperature fouling in brown coal-fired power utilities are reported in this paper. Binding of sodium is crucial to prevent deposition of condensable sodium salts in the convection sections of pulverized coal-fired boilers. Experiments using mixtures of candidate additives with different sodium compounds were conducted in a drop tube furnace. Sodium could be effectively captured by clay-type mineral additives, particularly kaolin as experiments showed. Pre-treated with alumina, earlier data using coal particles complement our results obtained with inorganic mixtures. For pulverized coal conversion processes based on Victorian brown coal, lo-201rm kaolin making up 2-3 wt%. The percentage of the feed was estimated to effectively reduce fouling. 99100963 Research on production of high quality foundry coke in 754ype non-recoverable double-coke oven Wang, X. Meitan Zhuanhua, 1997, 20, (4), 41-45. (In Chinese) Topics discussed include: structure and features of 75-type non-recoverable double-coke oven, production techniques of high quality foundry coke and the factors affecting quality of coke. 99100964 Selective maceral enrichment during grinding and effect of particle size on coal devolatilization yields Man, C. K. et al. Fuel Process. Technol., 1998, 56, (3), 215-227. By rapid heating of a range of particle-size fractions prepared from three different coals the effect of coal particle size on volatiles yields was observed. The yields obtained were measured using a wire-mesh apparatus. Samples were pyrolysed in helium at heating rates of 1000 K/s to 950°C with a 10 second hold time. Particle-size fractions of 38-150 pm were prepared using two methods, sieving from a ground coal and regrinding the largestsieved size fraction. The latter approach was used in an effort to minimize differences in size-cut compositions. Total dry ash-free basis volatile yields
Solid fuels (preparation)
capture activity at low temperature. During coal gasification at high temperature, iron played a role as sulfur-transfer in the desulfurization. Calcium-iron complex desulfurizers increased sulfur capture efficiency. The sulfur capture efficiency was affected by the ratio of iron to sulfur and calcium to sulfur. CO2 acted to suppress in-situ sulfur capture and Fe& decomposition and changed greatly the crystallized state of products.
Integrated technique for pyritic sulfur reduction in 99100952 Indian (Assam) coal Bhatnagar, A. et al. Energy Convers. Manage., 1998, 39, (11). 1121-1126. Using a pyrite oxidizing organism such as Thiobacillus ferrooxidans, microbial desulfurization of coal results in approximately 90% pyritic sulfur reduction in 30 density. An integrated technique, comprised of bacterial preconditioning and subsequent oil agglomeration, is concerned with surface modification of the pyrite by short contacts (2-240 min) with a culture of Thiobacillus ferrooxidans and its rejection during agglomeration. Coal (-250 pm) was preconditioned with the bacterial culture for 2.5-30 min before subjecting it to oil agglomeration. About 75-80% ash rejection and 90-97% pyritic sulfur reduction (PSRD) have been obtained. Extending preconditioning for 240 min could not improve the PSRD beyond 97%. By increasing the particle size from -250 pm to -800 + 400 Frn the PSRD decreased from 97% to 71%, whereas prolonging the preconditioning period to 240 min enhanced the PSRD to 90%. The integrated technique has considerably reduced the time requirement from 20-30 density to 30-240 min in order to obtain 90% pyritic sulfur reduction. Compared to traditionally used petroleum fractions, castor oil has been used as the agglomerant and found to be a good substitute.
Manufacture of needle coke 99100953 Shibata, K. et al. Jpn. Kokai Tokkyo Koho JP 10 168,461 [98 168,461] (Cl. ClOC3/02), 23 Jun 1998, Appl. 96/334,157, 13 Dee 1996, 5 pp. (In Japanese) High-quality needle coke can be manufactured by using coal tar raw material generated by adding recycle coal tar or coal-tar pitch to coal charge in a coke oven. The coal tar raw material contains 6-10 wt% phenanthrene. The needle coke manufactured can be used as graphite electrode. Method for increasing the charring ratio of coal 99100954 Cho, M. Y. et al. PCT Int. Appl. WO 98 28,385 (Cl. ClOL9/10), 2 Jul 1998, KR Appl. 9,673,769, 27 Dee 1996, 20 pp. A method for increasing the charring ratio of coal is discussed. An iron ingot using coal, magnesium oxide or limestone is used in manufacturing as an additive for charring coal. The additive increases the charring ratio of the coal without affecting the slag. Coal is mixed with an MgO suspension or limestone suspension. The mixture is dried to attach MgO or the limestone onto the surface of the coal. The charring effect is increased and hence the amount of coke used can be reduced. Numerical modeling of waste heat recovery boiler 99100955 Meyyappan, M. et al. Heat Mass Transfer Australas. 1996, Proc. Conf., 6th, C. 1996, (Pub. 1998) 303-311. Edited by Leonardi, E. and Madhusudana, V., Bengell House, New York. As a part of a consulting study undertaken by the Cooperative Center for New Technologies for Power Generation from Low-Rank Coal (CRC), a waste heat recovery boiler utilizing plant off-gas was numerically modelled, using the code CFDSFLOW3D (1994). The principal aim of the work was to estimate temperatures of char and the dust within the boiler to determine the likelihood of deposition onto the boiler walls. A series of solution strategies were adopted to overcome the difficulties in achieving convergence for this problem which were due to its complex shape and multiple blocking. Two areas were covered - the results of simulating operation in which only plant off-gas and char are combusted (Mode 1) and operation in which natural gas and melter gas are injected (Mode 3). For Mode 1 the model predicted good mixing in the region between the primary and secondary air jets and a nearly 100% char burnout. Most of the char and primary concentrate particles hitting the walls are cooler than the respectively critical temperatures identified for sticking at the boiler walls. Based on Flamelet modelling, combustion essentially takes place at and below the primary air jet plane. For Mode 3, the maximum temperature predicted agrees with the expected maximum adiabatic temperature for the natural gas combustion. Procedure for separation of ballast particles of coal 99100956 Kahnt, G. et al. Ger. Offen., DE 19,700,471 (Cl. ClOL5/04), 16 Jul 1998, Appl. 19,700,471, 9 Jan 1997, 8 pp. (In German) This paper discusses the four stages which are involved in a simple separation of ballast particles of coal, brown coal in particular. Stage 1 - a classification to obtain a fraction of 510 mm diameter (preferably <6 mm diameter). Stage 2 - drying at 105-125” to a predetermined moisture content (e.g. 520%). Stage 3 - charging into a horizontal air stream having a predetermined flow rate from a port located above the air stream. Stage 4 - removal of the ballast particles to withdrawal positions located below the air stream in relation to the particle mass and flow rate.
102
Fuel and Energy Abstracts
March 1999
99100957 Progress and energy effects of weathering and degassing of solid fuels Postrzednik, S. Energy Convers. Manage., 1998. 39, (16-18). 1883-1889. Low temperature oxidation of solid fuels is the main phenomenon of weathering and self heating of the combustible substance. Additionally, the degassing and low temperature devolatilization of the solid fuel and the transport of water vapour through the solid fuel bed are of importance. In this paper, energy losses and the ecological aspects of solid fuel weathering (self heating, endogenous fires, gas explosions) are discussed. A method of the energy consumption determination in the weathering process of solid fuel, treated as a physical and chemical process, by using the kinetic relations of the main phenomena is proposed. 99100956 Pyrolysis of coal in a fluidized bed reactor I. Effect of temperature on the devolatilization Li, H. et al. Ranliao Huaxue Xuebao, 1998, 26, (3). 238-242. (In Chinese) A specially designed fluidized-bed reactor (I.D. 48 mm) and a cone-shaped distributor were used to pyrolyse Shenmu coal (-45+80 mesh). The relationship between the gas-phase product yield and the dense-phase temperature was derived. While the yields of HZ, CO, CHI and CzH4 increased dramatically with increasing dense-phase temperature, the liquid yield reaches the maximum at a dense-phase temperature of 600-650°C. When the freeboard temperature is high, coal volatiles can undergo significant secondary reactions even at a very short residence time. The results were believed to represent a more accurate trend of the effect of bed temperature on gas-phase product yield because secondary reactions in the vapour phase were minimized. Pyrolysis of coal in fluidized bed reactors 99100959 Li, H. et al. Meitan Zhuanhua, 1997, 20, (4). 9-14. (In Chinese) The pyrolysis of coal in fluidized bed reactors is discussed with emphases apparatus, equipment and affecting factors.
on
99100960 Pyrolysis of coal with hydrogen-rich gases. 2. Desulfurization and denitrogenation in coal pyrolysis under coke-oven gas and synthesis gas Liao, H. et al. Fuel, 1998, 77, (14), 1643-1646. Desulfurization and denitrogenation were investigated by analysing the chars and tars from pyrolysis of high sulfur Chinese Yanzhou bituminous coal with coke-oven gas (COG), synthesis gas (SG), Ha and Nz at different operating conditions. It is found that desulfurization and denitrogenation in coal pyrolysis with COG, SG and Hz are about 20% and IO-20% higher than those under Nz, respectively. At the same hydrogen partial pressure, desulfurization under COG (5 MPa) is about 4.5% higher than that under Hz (3 MPa), while the denitrogenation is about 3.5% lower. 99100961 Rapid operation of beneficiation plants with respect to the ash content factor of run-of-mine coals Fon, M. G. et al. Koks K&m., 1998, (4), 4-5. (In Russian) The reliability of the prediction of the theoretical balance of coal beneficiation products in preparation plants, the determination of the fractional composition of coals from their ash content and the ash content as a determining factor of classification parameters are the focus of this work. 99100962 Reducing fouling from brown coals by sodiumbinding additives Vuthaluru, H. B. ef al. Fuel Process. Technol., 1998, 55, (2), 161-173. The methods to control medium-temperature fouling in brown coal-fired power utilities are reported in this paper. Binding of sodium is crucial to prevent deposition of condensable sodium salts in the convection sections of pulverized coal-fired boilers. Experiments using mixtures of candidate additives with different sodium compounds were conducted in a drop tube furnace. Sodium could be effectively captured by clay-type mineral additives, particularly kaolin as experiments showed. Pre-treated with alumina, earlier data using coal particles complement our results obtained with inorganic mixtures. For pulverized coal conversion processes based on Victorian brown coal, lo-201rm kaolin making up 2-3 wt%. The percentage of the feed was estimated to effectively reduce fouling. 99100963 Research on production of high quality foundry coke in 754ype non-recoverable double-coke oven Wang, X. Meitan Zhuanhua, 1997, 20, (4), 41-45. (In Chinese) Topics discussed include: structure and features of 75-type non-recoverable double-coke oven, production techniques of high quality foundry coke and the factors affecting quality of coke. 99100964 Selective maceral enrichment during grinding and effect of particle size on coal devolatilization yields Man, C. K. et al. Fuel Process. Technol., 1998, 56, (3), 215-227. By rapid heating of a range of particle-size fractions prepared from three different coals the effect of coal particle size on volatiles yields was observed. The yields obtained were measured using a wire-mesh apparatus. Samples were pyrolysed in helium at heating rates of 1000 K/s to 950°C with a 10 second hold time. Particle-size fractions of 38-150 pm were prepared using two methods, sieving from a ground coal and regrinding the largestsieved size fraction. The latter approach was used in an effort to minimize differences in size-cut compositions. Total dry ash-free basis volatile yields