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00521 Characteristics of underground coal combustion
09
Combustion
(burners, combustion systems)
98/00510 Vortex combustion of solid fuel in boilers with horizontal and vertical cyclone forechambers Korchevoi, Y. P. &erg. Elekrrif 1997, (2). 7-10. (In Russian) Coals containing 35 wt% ash and 10-40 wt% volatiles can be burned in boilers with horizontal and vertical cyclone forechambers with minimum demand for supplemental fuel. Anthracite containing 4-9 wt% volatiles can be burned in these boilers without supplemental fuel.
09
COMBUSTION Burners,
Combustion
Systems
Activation energy for the oxidation of Malaysian 9810051i coal chars Haji-Sulaiman, M. Z. and Aroua, M. K. .I. Insr. Energy. 1997, 70, (483), 5256. Thermal gravimetric analysis was used to study the oxidation of two Malaysian coal chars. The Temperature Program Reaction technique, which employed the random pore model of Bhatia & Perlmutter, was used to analyse the weight-loss data. All experiments were conducted within a temperature range of 698-773 K and heating rates of 2-10 K min-’ with char samples in the size range 53-75 ,Lm. The random pore model can accurately describe the oxidation of char to yield activation energy. It is similar to that obtained from model free kinetics, provided the structural parameter ~1, which is an input to the model, is taken as an adjustable parameter.
98100512 Alkali release and adsorption by ash components and additives during the combustion of lignites Muchmore, C. B. et al. DGMK Tagungsber., 1997, 9703, (Proceedings ICCS ‘97, Volume 2), 1047-1050. Sodium and potassium release from lignite was studied in laboratory-scale combustion and gasification experiments. When 50% sewage sludge was added to the lignite, the alkali release decreased significantly, while kaolin addition showed no positive effect. At higher temperatures the alkali release was lower, indicating the enhanced reaction rate between the alkali metals and the ash compounds. 98100513
Analysis of combustion properties of mixed coal Qiu, S. et al. Shandong Jiancai Xueyuan Xuebao, 1997, 11, (1) 27-31, 36. (In Chinese) A study of three different kinds of coal and their blends in varying proportions used in the cement industry was performed by TGA. The combustion characteristics of these coal blends and their effects on clinkering are investigated.
98100514
Analysis of combustion properties of mixed coal Qiu, S. et al. Shandong Jiancai Xueyuon Xuebao, 1997, 11, (l), 27-31, 36. (In Chinese) TGA was used to analyse three different kinds of coal and their blends in different proportions used in the cement industry. The combustion characteristics of these coal blends and their effects on clinkering were investigated. Assessing coal quality impacts on PC [personal 9aioo5i 5 computer] combustion behaviour Niksa, S. DGMK Tugungsber., 1997, 9703, (Proceedings ICCS ‘97, Volume 2), 947-950. A computational approach based on FLASHCHAIN for assessing coal quality impacts that achieves the accuracy of laboratory testing for a fraction of the expense is introduced. Two applications are considered here. First, the model is used to identify the parameter values in the simple devolatilization rate expressions used in coal combustor simulators that mimic the FLASHCHAIN predictions. In the second application, predicted yields for rapid heating conditions and coal-nitrogen release are used as regression variables in engineering correlations to relate coal quality to NO, emissions and unburned carbon in ash from full-scale furnaces. Carbons as models for coal devolatilization and 9aioo516 combustion DGMK Tagungsber., 1997, 9703, (Proceedings ICCS ‘97, Jones, .I. M. et al. Volume 2), 1083-1086. Coal-fuelled power generation experiences problems from fuel-NO, emissions. Consequently, the fate of fuel-nitrogen during combustion is a topic of great interest and an understanding of how the different forms of nitrogen in coal are released during devolatilization and combustion is one approach towards predicting NO, emissions. Nitrogen-containing carbons were used as models to study NO, release during coal combustion. The
44
Fuel and Energy Abstracts
January 1999
presence of impregnated catalytic metals and chelated metal species were investigated in an attempt to examine the role of trace metals on nitrogen release during pyrolysis and combustion.
98100517 Catalytic influence of ash elements on NO, formation from bound nitrogen in coal combustion Kopsel, R. and Halang, S. DGMK Tagungsber., 1997, 9703, (Proceedings ICCS ‘97, Volume 2), 1119-l 122. NO, formation/reduction reactions are mainly catalytic. For the purpose of investigating the influence of coal ash comparative experiments were carried out with original, deashed. and impregnated lignite and hard coal. Further insight into the catalytic activity of ash components was obtained by experiments with selected gas mixtures over different bed materials in a quartz glass tube reactor. Conclusions were drawn on the proceeding reactions and the catalytic activity of the individual ash components. Many single ash components like CeO, MgO, and Fe203 are also effective as catalysts. CaS04 is largely inert iron oxide has the highest activity for NO reduction as well as NH-, oxidation to NO. 9810051a Characteristics of char combustion in a high temperature advanced furnace for the high performance power system Cho, S. M. et al. Proc. Int. Tech. Conf. Coal Util. Fuel Syst., 1997, 22, 233244.
Foster Wheeler Development Corporation, under the sponsorship of the United States Department of Energy-Pittsburgh Energy Technology Center, is developing a high performance power system (HIPPS) with a thermal-to-electricity conversion efficiency of more than 47%. This system is a coal-fired combined cycle system that employs a high temperature advanced furnace (HITAF) to transfer the heat to the air and steam working fluids. In the HIPPS plant, pulverized coal and sorbent are fed into the pyrolyzer where the coal is partially gasified to produce a low-Btu fuel gas and combustible char. The fuel gas is supplied to the gas turbine combustor and the char is burned in the HITAF. This paper examines char combustion in the HITAF. It presents laboratory characterization of char combustion and numerical simulation of char combustion in a subscale test combustor. The laboratory characterization tests are conducted to determine the char ignition index, relative fuel reactivity. and drop-tube furnace performance. Numerical simulation of char combustion at the Foster Wheeler CETF is performed using a state-of-the-art furnace combustion computational fluid dynamics (CFD) code. The results of the laboratory bench-scale tests to characterize the char and CFD simulation of a sub-scale test combustor are detailed in the paper. Characteristics of pulverized coal combustion with 9aioo5i 9 complex swirl jets. (1). Experiment CU. F. and Xu. J. Ranshao Kexue Yu Jiuhu, 1997, 3. (2). 190-196. (In Chinese) An experimental study into the characteristics of pulverized coal comhustion with complex swirl jets is reported. The tests used three types of coal (brown coal, bituminous coal and anthracite) and various concentrations of coal particles in the jets. The temperature distribution, several gaseous components’ distributions, heat radiation distribution and coal particle characterizations were measured. The effect of the type of coal and the concentration of coal particles in the jets on the combustion behaviours are discussed. The results show the advantages of the combustion and the study determined the properties of the combustor.
9aioo520 Characteristics of pulverized coal combustion with complex swirl jets. (2). Numerical simulation Cu, F. and Xu, J. Ranshao Kexue Yu Jishu, 1997. 3, (2), 197-205. (In Chinese) The numerical calculation of pulverized coal combustion with complex swirl jets is described. The computing process consists of several parts, including fluid turbulent flow, turbulent gaseous chemical reactions, gas-solid twophase flow, complex coal particle combustion, and flame radiation. Some advanced models and theories were applied in the simulations. The distributions of the temperature, gaseous components and concentration of particle and particle track, flame surface were computed. The results and the experiment agreed well and thus the combustion characteristics were derived. 9aioo52i
Characteristics of underground coal combustion Troshen’kin. B. A. and Markosova. V. P. Ugol’ Ukr., 1996, (2) 6-7. (In Russian) At1300 K it is controlled by diffusion. Correlations are given for gas velocity in air injection and production wells and Nusselt number under underground combustion conditions.
98100522
Characterization multicomponent fuel effects during the initial stages of pulverized coal combustion ICCS Niksa, S. and Cho, S. DGMK Tagungsber.. 1997, 9703, (Proceedings ‘97, Volume 2), 1147-1150. The paper reports the complete distributions of all major products for the oxidative pyrolysis and combustion of premixed suspensions of suhbituminous, Pit. #8 hvA bituminous, and low volatile bituminous coals after 150 ms in a one-dimensional coal flame. As inlet O2 levels were progressively increased from 0 to 15% in successive tests, the process
Combustion
(burners, combustion systems)
98/00510 Vortex combustion of solid fuel in boilers with horizontal and vertical cyclone forechambers Korchevoi, Y. P. &erg. Elekrrif 1997, (2). 7-10. (In Russian) Coals containing 35 wt% ash and 10-40 wt% volatiles can be burned in boilers with horizontal and vertical cyclone forechambers with minimum demand for supplemental fuel. Anthracite containing 4-9 wt% volatiles can be burned in these boilers without supplemental fuel.
09
COMBUSTION Burners,
Combustion
Systems
Activation energy for the oxidation of Malaysian 9810051i coal chars Haji-Sulaiman, M. Z. and Aroua, M. K. .I. Insr. Energy. 1997, 70, (483), 5256. Thermal gravimetric analysis was used to study the oxidation of two Malaysian coal chars. The Temperature Program Reaction technique, which employed the random pore model of Bhatia & Perlmutter, was used to analyse the weight-loss data. All experiments were conducted within a temperature range of 698-773 K and heating rates of 2-10 K min-’ with char samples in the size range 53-75 ,Lm. The random pore model can accurately describe the oxidation of char to yield activation energy. It is similar to that obtained from model free kinetics, provided the structural parameter ~1, which is an input to the model, is taken as an adjustable parameter.
98100512 Alkali release and adsorption by ash components and additives during the combustion of lignites Muchmore, C. B. et al. DGMK Tagungsber., 1997, 9703, (Proceedings ICCS ‘97, Volume 2), 1047-1050. Sodium and potassium release from lignite was studied in laboratory-scale combustion and gasification experiments. When 50% sewage sludge was added to the lignite, the alkali release decreased significantly, while kaolin addition showed no positive effect. At higher temperatures the alkali release was lower, indicating the enhanced reaction rate between the alkali metals and the ash compounds. 98100513
Analysis of combustion properties of mixed coal Qiu, S. et al. Shandong Jiancai Xueyuan Xuebao, 1997, 11, (1) 27-31, 36. (In Chinese) A study of three different kinds of coal and their blends in varying proportions used in the cement industry was performed by TGA. The combustion characteristics of these coal blends and their effects on clinkering are investigated.
98100514
Analysis of combustion properties of mixed coal Qiu, S. et al. Shandong Jiancai Xueyuon Xuebao, 1997, 11, (l), 27-31, 36. (In Chinese) TGA was used to analyse three different kinds of coal and their blends in different proportions used in the cement industry. The combustion characteristics of these coal blends and their effects on clinkering were investigated. Assessing coal quality impacts on PC [personal 9aioo5i 5 computer] combustion behaviour Niksa, S. DGMK Tugungsber., 1997, 9703, (Proceedings ICCS ‘97, Volume 2), 947-950. A computational approach based on FLASHCHAIN for assessing coal quality impacts that achieves the accuracy of laboratory testing for a fraction of the expense is introduced. Two applications are considered here. First, the model is used to identify the parameter values in the simple devolatilization rate expressions used in coal combustor simulators that mimic the FLASHCHAIN predictions. In the second application, predicted yields for rapid heating conditions and coal-nitrogen release are used as regression variables in engineering correlations to relate coal quality to NO, emissions and unburned carbon in ash from full-scale furnaces. Carbons as models for coal devolatilization and 9aioo516 combustion DGMK Tagungsber., 1997, 9703, (Proceedings ICCS ‘97, Jones, .I. M. et al. Volume 2), 1083-1086. Coal-fuelled power generation experiences problems from fuel-NO, emissions. Consequently, the fate of fuel-nitrogen during combustion is a topic of great interest and an understanding of how the different forms of nitrogen in coal are released during devolatilization and combustion is one approach towards predicting NO, emissions. Nitrogen-containing carbons were used as models to study NO, release during coal combustion. The
44
Fuel and Energy Abstracts
January 1999
presence of impregnated catalytic metals and chelated metal species were investigated in an attempt to examine the role of trace metals on nitrogen release during pyrolysis and combustion.
98100517 Catalytic influence of ash elements on NO, formation from bound nitrogen in coal combustion Kopsel, R. and Halang, S. DGMK Tagungsber., 1997, 9703, (Proceedings ICCS ‘97, Volume 2), 1119-l 122. NO, formation/reduction reactions are mainly catalytic. For the purpose of investigating the influence of coal ash comparative experiments were carried out with original, deashed. and impregnated lignite and hard coal. Further insight into the catalytic activity of ash components was obtained by experiments with selected gas mixtures over different bed materials in a quartz glass tube reactor. Conclusions were drawn on the proceeding reactions and the catalytic activity of the individual ash components. Many single ash components like CeO, MgO, and Fe203 are also effective as catalysts. CaS04 is largely inert iron oxide has the highest activity for NO reduction as well as NH-, oxidation to NO. 9810051a Characteristics of char combustion in a high temperature advanced furnace for the high performance power system Cho, S. M. et al. Proc. Int. Tech. Conf. Coal Util. Fuel Syst., 1997, 22, 233244.
Foster Wheeler Development Corporation, under the sponsorship of the United States Department of Energy-Pittsburgh Energy Technology Center, is developing a high performance power system (HIPPS) with a thermal-to-electricity conversion efficiency of more than 47%. This system is a coal-fired combined cycle system that employs a high temperature advanced furnace (HITAF) to transfer the heat to the air and steam working fluids. In the HIPPS plant, pulverized coal and sorbent are fed into the pyrolyzer where the coal is partially gasified to produce a low-Btu fuel gas and combustible char. The fuel gas is supplied to the gas turbine combustor and the char is burned in the HITAF. This paper examines char combustion in the HITAF. It presents laboratory characterization of char combustion and numerical simulation of char combustion in a subscale test combustor. The laboratory characterization tests are conducted to determine the char ignition index, relative fuel reactivity. and drop-tube furnace performance. Numerical simulation of char combustion at the Foster Wheeler CETF is performed using a state-of-the-art furnace combustion computational fluid dynamics (CFD) code. The results of the laboratory bench-scale tests to characterize the char and CFD simulation of a sub-scale test combustor are detailed in the paper. Characteristics of pulverized coal combustion with 9aioo5i 9 complex swirl jets. (1). Experiment CU. F. and Xu. J. Ranshao Kexue Yu Jiuhu, 1997, 3. (2). 190-196. (In Chinese) An experimental study into the characteristics of pulverized coal comhustion with complex swirl jets is reported. The tests used three types of coal (brown coal, bituminous coal and anthracite) and various concentrations of coal particles in the jets. The temperature distribution, several gaseous components’ distributions, heat radiation distribution and coal particle characterizations were measured. The effect of the type of coal and the concentration of coal particles in the jets on the combustion behaviours are discussed. The results show the advantages of the combustion and the study determined the properties of the combustor.
9aioo520 Characteristics of pulverized coal combustion with complex swirl jets. (2). Numerical simulation Cu, F. and Xu, J. Ranshao Kexue Yu Jishu, 1997. 3, (2), 197-205. (In Chinese) The numerical calculation of pulverized coal combustion with complex swirl jets is described. The computing process consists of several parts, including fluid turbulent flow, turbulent gaseous chemical reactions, gas-solid twophase flow, complex coal particle combustion, and flame radiation. Some advanced models and theories were applied in the simulations. The distributions of the temperature, gaseous components and concentration of particle and particle track, flame surface were computed. The results and the experiment agreed well and thus the combustion characteristics were derived. 9aioo52i
Characteristics of underground coal combustion Troshen’kin. B. A. and Markosova. V. P. Ugol’ Ukr., 1996, (2) 6-7. (In Russian) At
98100522
Characterization multicomponent fuel effects during the initial stages of pulverized coal combustion ICCS Niksa, S. and Cho, S. DGMK Tagungsber.. 1997, 9703, (Proceedings ‘97, Volume 2), 1147-1150. The paper reports the complete distributions of all major products for the oxidative pyrolysis and combustion of premixed suspensions of suhbituminous, Pit. #8 hvA bituminous, and low volatile bituminous coals after 150 ms in a one-dimensional coal flame. As inlet O2 levels were progressively increased from 0 to 15% in successive tests, the process