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03261 Empirical correlations of the ash fusion temperatures and temperature of critical viscosity for coal and biomass ashes
04 By-products
injection into coal-heds have shown mcreased yields of produced CH4 over conventional coal-bed methane recovery. These coal deposits represent a widely dispersed potential geological sink for CO2 storage while at the same time offering an opportunity to recover commercial quantities of natural gas from coal-beds. The US Department of Energy has been facilitating the evolving recognition and development of this novel CO&H? concept in order to enhance coal-bed methane production and evaluate a potential geological option for the disposal of carbon dioxide from power plant stack gases. 00103257 Detailed modeling of soot formation in hydrocarbon pyrolysis Krestinin, A. V. Comhus/ron und F/me, 2000, 121. (3), 513-524. Extended calculations of soot formation in the pyrolysis of a number of hydrocarbons varying in chemical structure have been performed. The computer code for soot formation was based on the ‘polyyne model’, which uses the ‘acetylene pathway’ to soot particles. The model treats soot formation as a process of chemical condensation (polymerization) of supersaturated polyyne vapour (Cz,zH2, ~1 = 2, 3,...). This process results in polymeric globules as primary soot particles. The computer code is based on a detailed description of both gas-phase and heterogeneous reactions, soot particle nucleation, their surface growth and coalescence. The principal parameters for soot formation, such as induction time, soot particle number density, and soot volume fraction over a wide temperature range have been calculated. There is good quantitative agreement between these calculations and available experimental measurements for methane, acetylene, ethylene, diacetylene, benzene, and naphthalene as fuel. 00/03258 Effect of low-level boron doping on oxidation behavior of polyimide-derived carbon films Zhong, D. H. Carbon, 2000, 38, (S), 119991206. The oxidation behaviour of polyimid$-derived carbon films doped with boron in low levels (up to 1.23 x 10 _ B/C) was investigated by means of thermogravimetric analysis (TGA). It was observed that boron-doping less than 7.09 x 10 a B/C in the carbon film formed at 1500°C had a catalytic effect on the oxidation of the carbon. Based on a kinetic analysis, it is revealed that four factors - the catalytic effect and the inhibiting effect of substitutional boron, the improvement of graphitization due to boron doping, and the formation of BZOa during oxidation - may contribute to the appearance of the oxidation process. The catalytic effect would be dominant up to some level of carbon burn-off when less boron is doped; the contribution of the inhibiting effect(s) may rapidly become dominant when more doped boron is employed. 00103259 Effect of pressure on sulphur capture and NOx/NPO emissions during pressurized fluidized bed combustion of coal Nagel, H. et al. Proc. In!. Cmf. Fluid. Bed Comhus~.. 1999. 594-609. There are particular advantages of pressurized fluidized bed combustion over conventional firing systems, e.g. in silu pollutant removal (SO*) and high thermal efficiencies even in intermediate power ranges. The low combustion temperature of about 1050-1200 K results in low NO emissions without any secondary flue gas treatment but on the other hand yields considerable NzO emissions. To know in which way the operatmg pressure influences the gaseous emissions of PFBC, especially SO?, NO and NlO were studied. Furthermore, examinations were made as to what extent the experiences from AFBC, e.g. influence of temperature, air ratio and additives on pollutant formation, can be transferred to pressurized conditions. At the IVD’s PFBC test facility (SO kW thermal power) various experiments were carried out with two different coals (high volatile bituminous coal and sub-bituminous coal) at defined operating temperatures in the range of 1073-1213 K. and pressures from 1.5 to I3 bar. Dolomite and calcinated lime were used as additives for in .si/u sulfur capture at different molar ratios in each case and its influence on NO and NaO emissions were studied. It was found that NO emissions decreased with Increasing pressure and increasing Ca:S molar ratio. At pressures above 4 bar and with more sorbent addition, NO emissions decreased with increasing temperature N20 emissions showed no significant decrease at elevated pressures and were not influenced by dolomite or CaO added, but were found to depend on CO emissions or, rather, carbon conversion. At higher system pressures better carbon conversion rates could be achieved (higher O2 partial pressure), which results in lower CO concentrations in the fluidized bed and the freeboard, respectively. As a result, the reduction of NO to NzO decreases so that compared with atmospheric operation mode the overall NzO emissions in a PFBC are lower.
related
to fuels
from Regression analysis has been used to derive empirical correlations which one can calculate the ash fusion temperatures under reducing conditions and the temperature of critical viscosity from the ash chemical composition, The database used in this work includes about 300 ash samples from coals of different sources and hiomasses. The standard deviation, 0, for these equations are generally about 45-80°C. These fall within the experimental errors of the measurements. These correlations: (1) provide a total for calculating the thermal properties of the ash from its chemical composition and (2) provide a method to predict the effect of adding minerals (such as CaO) normally used to modify the slag behaviour. 00103262 Experience with the operation of high-capacity cokeoven batteries Lohov, A. A. el crl. K&s Khim, 1999. 3. 9 14. (In Russian) This paper describes the long time operational experience (dating back to 1980 and 1982) of 7 m coke-oven batteries in a by-product coking plant. 00/03263 False deformation temperatures for ash fusibility associated with the conditions for ash preparation Wall, T. F. e/ crl. Fuel, 1999, 78, (9), 1057-1063. A study was made to investigate the fusibility behaviour of coal ashes of high ash fusion temperatures. Coals and ashes formed in the boiler were sampled in several Australian power stations, with laboratory ashes being prepared from the coals. The laboratory ashes gave lower values for the deformation temperature (DT) than the combustion ashes when the ash had low levels of basic oxide components. Thermomechanical analysis, quantifiable X-ray diffraction and SEM were used to establish the mechanisms responsible for the difference. Laboratory ash was finer than combustion ash and included unreacted minerals (such as quartz, kaolinite and illite) and anhydrite (CaSOJ). Fusion events which appear to be characteristic of reacting illite, at temperatures from 900 to 12OO”C, were observed for the laboratory ashes, these being associated with the formation of melt phase and substantial shrinkage. The combustion ashes did not contain this mineral and their fusion events were observed at temperatures exceeding 1300°C. The low DTs of coal ashes with low levels of basic oxides are therefore a characteristic of laboratory ash rather than that found in practical combustion systems. It is not expected that these low temperatures are to be associated with slagging in pulverized coal fired systems. 00/03264 Heat recovery from lean industrial methane emissions. Environmental and economic benefits of CFRR technology Sapoundjiev, H. et (II. Greenhouse Gus Control Tc~chnol., Proc. Inr. Conf:, 4rh, 1999, 805-810. Edited by Ehasson A. ri al. Out of the approximately 1 billion equivalent tons of carbon dioxide emitted yearly by the industrial sectors, the diluted (0.1-1.0 vol/vol%) methane emissions from industrial activities (underground coal mining, natural gas and petroleum and petrochemical primary and secondary production) constitute a major fraction. Natural Resources Canada technology can technically eliminate the methane of no less than 20% of these emissions, and application of its catalytic flow reversal reactor (CFRR) technology can be economically justified for a quarter of this market. The CFRR technology will also recover the methane heat value, with an efficiency of up to 90%, further reducmg greenhouse gas emissions by correspondingly decreasing world energy consumption. OOlO3265 Hydrogen production from coal and coal bed methane, using byproduct COP for enhanced methane recovery and sequestering the COB in the coal bed Williams, R. H. Greenltou.se Gas Confrol Techrio/. Proc. Inc. Conf.. 4rh. 1999. 799-804. Edited by Eliasson B. ef a/ Renewed interest is being created for the use 01 hydrogen, due to rapid advances in proton exchange membrane fuel cell technology which use hydrogen as the preferred fuel for these fuel cells. A promising strategy for providing hydrogen for fuel cells in countries such as China that are poorly endowed with conventional hydrocarbon resources but coal and coal bed methane-rich, would be to produce it from coal and coal bed methane, using the low-cost CO2 generated as a by-product of hydrogen production to stimulate the recovery of methane from deep beds of unminable coal. While awaiting the arrival of fuel cells for major commercial applications, hydrogen so produced might be used in the manufacture of ammonia for fertilizer, as a less costly option than making hydrogen from coal only, as is done at present in China. Moreover, because the CO2 injected into the coal bed for methane recovery would be sequestered there, the production of hydrogen in this manner would lead to low levels of lifecycle COa emissions.
00/03260 Efficient operation of hydrogen-absorbing metal hydride system using heat pump Popovich, V. A. Prohl. Mashrnos~r N&zhno,sri Mash.. 1999. 2, 83-88. (In Russian) This study obtained mathematical relationships for an evaluation of the effective operation of a hydrogen-absorbing metal hydride system. Basic components of compression and temperature-increasing blocks with high technical efficiency are presented and evaluated.
00103266 Improvement of fly ash flotation process Feng, I. and Yan, C. Hrrrmjing Gongcht,n~, 1999. Ii. (3). 72-74. (In Chinese) In order to improve the original sieving-concentration filtration process, a sieving-flotation/sieving-dewatering process for the size classification of fly ash was proposed. The fly ash ohtained by the process was used as the light aggregate for producing bricks.
00/03261 Empirical correlations of the ash fusion temperatures and temperature of critical viscosity for coal and biomass ashes Seggiani, M. Fire!, 1999, 78. (9). 1121&l 125.
00103267 Intercalation of nickel atoms under two-dimensional graphene film on (1ll)lr Gall, N.R. E[ ul.Corhon, 2000, 38. (5).663-6617
Fuel and Energy Abstracts
November 2000
367
injection into coal-heds have shown mcreased yields of produced CH4 over conventional coal-bed methane recovery. These coal deposits represent a widely dispersed potential geological sink for CO2 storage while at the same time offering an opportunity to recover commercial quantities of natural gas from coal-beds. The US Department of Energy has been facilitating the evolving recognition and development of this novel CO&H? concept in order to enhance coal-bed methane production and evaluate a potential geological option for the disposal of carbon dioxide from power plant stack gases. 00103257 Detailed modeling of soot formation in hydrocarbon pyrolysis Krestinin, A. V. Comhus/ron und F/me, 2000, 121. (3), 513-524. Extended calculations of soot formation in the pyrolysis of a number of hydrocarbons varying in chemical structure have been performed. The computer code for soot formation was based on the ‘polyyne model’, which uses the ‘acetylene pathway’ to soot particles. The model treats soot formation as a process of chemical condensation (polymerization) of supersaturated polyyne vapour (Cz,zH2, ~1 = 2, 3,...). This process results in polymeric globules as primary soot particles. The computer code is based on a detailed description of both gas-phase and heterogeneous reactions, soot particle nucleation, their surface growth and coalescence. The principal parameters for soot formation, such as induction time, soot particle number density, and soot volume fraction over a wide temperature range have been calculated. There is good quantitative agreement between these calculations and available experimental measurements for methane, acetylene, ethylene, diacetylene, benzene, and naphthalene as fuel. 00/03258 Effect of low-level boron doping on oxidation behavior of polyimide-derived carbon films Zhong, D. H. Carbon, 2000, 38, (S), 119991206. The oxidation behaviour of polyimid$-derived carbon films doped with boron in low levels (up to 1.23 x 10 _ B/C) was investigated by means of thermogravimetric analysis (TGA). It was observed that boron-doping less than 7.09 x 10 a B/C in the carbon film formed at 1500°C had a catalytic effect on the oxidation of the carbon. Based on a kinetic analysis, it is revealed that four factors - the catalytic effect and the inhibiting effect of substitutional boron, the improvement of graphitization due to boron doping, and the formation of BZOa during oxidation - may contribute to the appearance of the oxidation process. The catalytic effect would be dominant up to some level of carbon burn-off when less boron is doped; the contribution of the inhibiting effect(s) may rapidly become dominant when more doped boron is employed. 00103259 Effect of pressure on sulphur capture and NOx/NPO emissions during pressurized fluidized bed combustion of coal Nagel, H. et al. Proc. In!. Cmf. Fluid. Bed Comhus~.. 1999. 594-609. There are particular advantages of pressurized fluidized bed combustion over conventional firing systems, e.g. in silu pollutant removal (SO*) and high thermal efficiencies even in intermediate power ranges. The low combustion temperature of about 1050-1200 K results in low NO emissions without any secondary flue gas treatment but on the other hand yields considerable NzO emissions. To know in which way the operatmg pressure influences the gaseous emissions of PFBC, especially SO?, NO and NlO were studied. Furthermore, examinations were made as to what extent the experiences from AFBC, e.g. influence of temperature, air ratio and additives on pollutant formation, can be transferred to pressurized conditions. At the IVD’s PFBC test facility (SO kW thermal power) various experiments were carried out with two different coals (high volatile bituminous coal and sub-bituminous coal) at defined operating temperatures in the range of 1073-1213 K. and pressures from 1.5 to I3 bar. Dolomite and calcinated lime were used as additives for in .si/u sulfur capture at different molar ratios in each case and its influence on NO and NaO emissions were studied. It was found that NO emissions decreased with Increasing pressure and increasing Ca:S molar ratio. At pressures above 4 bar and with more sorbent addition, NO emissions decreased with increasing temperature N20 emissions showed no significant decrease at elevated pressures and were not influenced by dolomite or CaO added, but were found to depend on CO emissions or, rather, carbon conversion. At higher system pressures better carbon conversion rates could be achieved (higher O2 partial pressure), which results in lower CO concentrations in the fluidized bed and the freeboard, respectively. As a result, the reduction of NO to NzO decreases so that compared with atmospheric operation mode the overall NzO emissions in a PFBC are lower.
related
to fuels
from Regression analysis has been used to derive empirical correlations which one can calculate the ash fusion temperatures under reducing conditions and the temperature of critical viscosity from the ash chemical composition, The database used in this work includes about 300 ash samples from coals of different sources and hiomasses. The standard deviation, 0, for these equations are generally about 45-80°C. These fall within the experimental errors of the measurements. These correlations: (1) provide a total for calculating the thermal properties of the ash from its chemical composition and (2) provide a method to predict the effect of adding minerals (such as CaO) normally used to modify the slag behaviour. 00103262 Experience with the operation of high-capacity cokeoven batteries Lohov, A. A. el crl. K&s Khim, 1999. 3. 9 14. (In Russian) This paper describes the long time operational experience (dating back to 1980 and 1982) of 7 m coke-oven batteries in a by-product coking plant. 00/03263 False deformation temperatures for ash fusibility associated with the conditions for ash preparation Wall, T. F. e/ crl. Fuel, 1999, 78, (9), 1057-1063. A study was made to investigate the fusibility behaviour of coal ashes of high ash fusion temperatures. Coals and ashes formed in the boiler were sampled in several Australian power stations, with laboratory ashes being prepared from the coals. The laboratory ashes gave lower values for the deformation temperature (DT) than the combustion ashes when the ash had low levels of basic oxide components. Thermomechanical analysis, quantifiable X-ray diffraction and SEM were used to establish the mechanisms responsible for the difference. Laboratory ash was finer than combustion ash and included unreacted minerals (such as quartz, kaolinite and illite) and anhydrite (CaSOJ). Fusion events which appear to be characteristic of reacting illite, at temperatures from 900 to 12OO”C, were observed for the laboratory ashes, these being associated with the formation of melt phase and substantial shrinkage. The combustion ashes did not contain this mineral and their fusion events were observed at temperatures exceeding 1300°C. The low DTs of coal ashes with low levels of basic oxides are therefore a characteristic of laboratory ash rather than that found in practical combustion systems. It is not expected that these low temperatures are to be associated with slagging in pulverized coal fired systems. 00/03264 Heat recovery from lean industrial methane emissions. Environmental and economic benefits of CFRR technology Sapoundjiev, H. et (II. Greenhouse Gus Control Tc~chnol., Proc. Inr. Conf:, 4rh, 1999, 805-810. Edited by Ehasson A. ri al. Out of the approximately 1 billion equivalent tons of carbon dioxide emitted yearly by the industrial sectors, the diluted (0.1-1.0 vol/vol%) methane emissions from industrial activities (underground coal mining, natural gas and petroleum and petrochemical primary and secondary production) constitute a major fraction. Natural Resources Canada technology can technically eliminate the methane of no less than 20% of these emissions, and application of its catalytic flow reversal reactor (CFRR) technology can be economically justified for a quarter of this market. The CFRR technology will also recover the methane heat value, with an efficiency of up to 90%, further reducmg greenhouse gas emissions by correspondingly decreasing world energy consumption. OOlO3265 Hydrogen production from coal and coal bed methane, using byproduct COP for enhanced methane recovery and sequestering the COB in the coal bed Williams, R. H. Greenltou.se Gas Confrol Techrio/. Proc. Inc. Conf.. 4rh. 1999. 799-804. Edited by Eliasson B. ef a/ Renewed interest is being created for the use 01 hydrogen, due to rapid advances in proton exchange membrane fuel cell technology which use hydrogen as the preferred fuel for these fuel cells. A promising strategy for providing hydrogen for fuel cells in countries such as China that are poorly endowed with conventional hydrocarbon resources but coal and coal bed methane-rich, would be to produce it from coal and coal bed methane, using the low-cost CO2 generated as a by-product of hydrogen production to stimulate the recovery of methane from deep beds of unminable coal. While awaiting the arrival of fuel cells for major commercial applications, hydrogen so produced might be used in the manufacture of ammonia for fertilizer, as a less costly option than making hydrogen from coal only, as is done at present in China. Moreover, because the CO2 injected into the coal bed for methane recovery would be sequestered there, the production of hydrogen in this manner would lead to low levels of lifecycle COa emissions.
00/03260 Efficient operation of hydrogen-absorbing metal hydride system using heat pump Popovich, V. A. Prohl. Mashrnos~r N&zhno,sri Mash.. 1999. 2, 83-88. (In Russian) This study obtained mathematical relationships for an evaluation of the effective operation of a hydrogen-absorbing metal hydride system. Basic components of compression and temperature-increasing blocks with high technical efficiency are presented and evaluated.
00103266 Improvement of fly ash flotation process Feng, I. and Yan, C. Hrrrmjing Gongcht,n~, 1999. Ii. (3). 72-74. (In Chinese) In order to improve the original sieving-concentration filtration process, a sieving-flotation/sieving-dewatering process for the size classification of fly ash was proposed. The fly ash ohtained by the process was used as the light aggregate for producing bricks.
00/03261 Empirical correlations of the ash fusion temperatures and temperature of critical viscosity for coal and biomass ashes Seggiani, M. Fire!, 1999, 78. (9). 1121&l 125.
00103267 Intercalation of nickel atoms under two-dimensional graphene film on (1ll)lr Gall, N.R. E[ ul.Corhon, 2000, 38. (5).663-6617
Fuel and Energy Abstracts
November 2000
367