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03155 Combustibility of coal for power plants
09
09
(burners, combustion
systems)
levels the unit was operated for combustion of very low-CV gas, giving rise to low exhaust temperatures and insufficient residence time for full oxidation of the CO.
COMBUSTION Burners, Combustion
Combustion
Systems
Association of environmental trace elements with 9am314a sulfide minerals. Significance in coal combustion Dale, L. S. et al. DGMK Tagung.sher., 1997,9704, (Proceedings ICCS ‘97, Volume 3). 1715-1718. The association of environmentally sensitive trace elements with sulfide minerals was determined via selective chemical leaching of raw coals. Using the IS0 standard method for determining sulfur forms the association of copper, zinc, arsenic, selenium, mercury, lead, chromium and nickel in a selection of Australian thermal coals was determined. Arsenic, selenium and copper were found to be substantially associated with sulfide minerals, whereas mercury, lead and zinc had only a minor association. The low recoveries for nickel and chromium suggest an association with other ironbearing minerals. 98103149
Calculation of the main operating parameters of an installation for combustion of coal in a fluidized bed
Petkov, V. and Stanev. R. Energetika, 1997, 49, (l/Z), 48-50. Reports on heat balance and the main characteristics of coal fluidized combustion, with sulfur capture by calcium sorbent.
bed
Characteristics of disintegration of a liquid fuel jet 9aio3150 across a high-temperature and high-speed airstream (1st report, spray shape obtained by ejecting the liquid fuel)
Oda, T. et al. Nippon Kikai Gakkai Ronhunshu, B-hen, 1997, 63, (615), 3764-3769. (In Japanese) In an attempt to elucidate the disintegrating process of the spray, a liquid fuel (kerosene) jet was ejected across high-temperature and a high-speed airstream. All tests were performed at an airstream velocity of 30-80 m/s and a temperature of 300-900 K. Scattered-light photographs with a long exposure time were taken to obtain spray shapes. Short exposure photographs were used to obtain detail of the spray near the injector. Although the effect of parameter, the momentum flux ratio of ejecting liquid to airstream, on the height of the spray outer line could be explained for the room temperature airstream, it could not be explained for the hightemperature as follows. Height of the spray outer line increases with the temperature of the airstream under the condition of the same momentum flux ratio and decreases with airstream velocity under the condition of the same momentum flux ratio. Height of the outer line hardly changed when the airstream temperature increased from SO0 K to 900 K under the condition of the same ratio of the mass flow rate of airstream to ejected fuel.
Characteristics of disintegration of jet across a high-temperature and high-steed airstream (2nd report, controlling the distribution of liquid fuel and combustion by means of a bubbling fuel liquid jet)
98103151
Oda, T. et al. Nippon Kikai Gakkai Ronhunshu, B-hen, 1997, 63, (615), 3770-3774. (In Japanese) In order to control the spray shape and temperature of the airstream under an airstream velocity of 80 m/s and a constant ejecting pressure, a bubbling liquid fuel (kerosene) jet was ejected in a normal to high-temperature and high-speed airstream. Spray shapes were obtained by taking scatter-light photographs with a long exposure time, the flame photographs were taken in the downstream region of the flame holder the temperature of the airstream was measured at the exit of the test section of the wind tunnel. The results are presented.
Clean and efficient combustion of simulated low98/03152 calorific-value gases in swirl burner/furnace systems
Fick, W. et al. J. Inst. Energy, March 1998, 71, 12-20. The performance of a large swirl burner/furnace system is examined in terms of its ability to burn simulated gases of very low calorific value efficiently. Previous work has demonstrated that the combustion behaviour and temperature levels produced by waste gas from production of carbon black can be simulated approximately by mixtures of natural gas diluted with substantial amounts of excess air. The system comprises a 2 MW swirl burner/furnace system that can be operated either non-premixed with axial fuel injection on the centreline, or piloted-premixed with up to 60% of the natural gas introduced axially on the centre line in order to pilot the flame and enable the flame detector to monitor the flame front. The results are discussed in terms of the system aerodynamics and, in particular, the influence of coherent structures on the flame stabilization process, temperature, power, excess air levels, mode of fuel entry and emissions of NO, and CO. In particular it is shown that gases of very low calorific value can be efficiently burnt when small amounts of piloting or support fuel are introduced axially on the centre line. Although very low NO, emission levels can be achieved with premixed or simulated low-CV gas consumption, some penalty accrues in terms of CO emission levels-which are typically around 150 ppm as distinct from 50 ppm with non-premixed combustion or for simulated low-CV gases. This probably arises from the very low power
98/03153
Coal combustion research in CSIRO
98/03154
Coal science impact on combustion technology
Weright, J. W. Proc. Annu. Int. Pittsburgh Coal Conf., 1996, 13, (I), 637642. Australia’s leading research organization, CSIRO (Commonwealth Scientific and Industrial Research Organization) contains the Division of Coal and Energy Technology. History and general information about research at CSIRO are given. Coal research in relation to combustion and pyrolysis, gasification, coal minerals, and environmental implications of coal combustion are described.
Beer, J. M. DGMK Tagungsber., 1997, 9702, (Proceedings ICCS ‘97, Volume l), 19-23. The paper reviews selected research works on the combustion process of coal, pollutant release control, fly ash utilization in cement manufacturing and the transformation of mineral matter during coal combustion.
99lo3155
Combustibility of coal for power plants
Zheng, M. and Yao, B. Ranliao Huaxue Xuebao. 1996, 24, (6). 565-570. (In Chinese) For five typical coals for power stations with volatile matter from about 20 to 40%, combustibility curves, characteristic temperatures and kinetic parameters were obtained by ordinary analysis and thermogravimetry analysis techniques. 95103156 Combustion behavior of oxidized coals Rincon, .I. M. et al. DGMK Tugungsber., 1997, 9702, (Proceedings ICCS ‘97, Volume l), 313-316. Coal combustion behaviour was investigated to find out the influence of pre-oxidation. Three bituminous coals were demineralized. The oxidation isotherms at 180, 200, and 230°C were monitored during 24 h and the burning profiles were recorded. The oxygen chemisorption kinetics were studied and the activation energy was estimated to be 70-93 kJ/mol. The mineral matter and the moiety of oxidized coal improve the combustibility properties of coal.
95lo3157 Comprehensive modelling of pulverized coal combustion in a vortex combustor
Zhang, J. and Nieh, S. Fuel, 1997, 76, (2) 123-131. A comprehensive numerical modelling is introduced for the strongly swirling gas-particle turbulent flow and pulverized coal combustion in a recently developed vortex comhustor (VC) for commercial heating applications. A comprehensive two-dimensional coal combustion model was developed which incorporates a new algebraic Reynolds stress turbulence model (ASM). The numerical results for an 88 kW coal fired VC describe the detailed characteristics of the gas-particle flow and combustion in terms of gas velocities, turbulence quantities, temperature, species concentrations, particle density, trajectories, burnout time and residence time. All of these are important to the design and operation of the VC. 9am3i
58 The computation of particle Eulerian models of coal combustion
size in Eulerian-
Fueyo, N. et al. Int. J. Multiphase Flow, 1997, 23, (3). 607-612. The average particle size in the framework of an Eulerian model can be calculated by the method presented here, with allowance for the size diminution due to mass transfer and for a phenomenological representation of other mechanisms which may cause a particle-size change. The method is first validated by comparison with the case which has an analysis solution and then it is applied, in combination with an Eulerian-Eulerian model of coal combustion, to an actual power production boiler. The EulerianEulerian models of coal combustion can be supplied with a method which allows the calculation of the evolution of the mean particle size. The effects of burnout in size diminution and of volatilization in particle swelling and fragmentation is shown. The method can be incorporated further models of particle size evolution.
Computer-aided study on the influence of catalysts 9#03159 on coal combustion property. (IV). Catalytic influence and the mechanics of transition metal oxides and salts catalysts on coal combustion Wu, Z.-h. et al. Jisuanji Yu Yingyong Huaxue, 1998, 15, (1). 49-52 (In Chinese) Typically, ignition temperature measurements are used to study the effects of various catalysts on coal combustion properties. However, in this paper, gas componentsanalysis with gas chromatography is used to examine the influence and mechanisms of transition metal oxides and salts on coal combustion properties. The results show that some of the catalysts have activities on the homogeneous combustion, lowering the ignition temperature, and/or the heterogeneous combustion, promoting the carbon oxidation.
Fuel and Energy Abstracts
July 1999 291
09
(burners, combustion
systems)
levels the unit was operated for combustion of very low-CV gas, giving rise to low exhaust temperatures and insufficient residence time for full oxidation of the CO.
COMBUSTION Burners, Combustion
Combustion
Systems
Association of environmental trace elements with 9am314a sulfide minerals. Significance in coal combustion Dale, L. S. et al. DGMK Tagung.sher., 1997,9704, (Proceedings ICCS ‘97, Volume 3). 1715-1718. The association of environmentally sensitive trace elements with sulfide minerals was determined via selective chemical leaching of raw coals. Using the IS0 standard method for determining sulfur forms the association of copper, zinc, arsenic, selenium, mercury, lead, chromium and nickel in a selection of Australian thermal coals was determined. Arsenic, selenium and copper were found to be substantially associated with sulfide minerals, whereas mercury, lead and zinc had only a minor association. The low recoveries for nickel and chromium suggest an association with other ironbearing minerals. 98103149
Calculation of the main operating parameters of an installation for combustion of coal in a fluidized bed
Petkov, V. and Stanev. R. Energetika, 1997, 49, (l/Z), 48-50. Reports on heat balance and the main characteristics of coal fluidized combustion, with sulfur capture by calcium sorbent.
bed
Characteristics of disintegration of a liquid fuel jet 9aio3150 across a high-temperature and high-speed airstream (1st report, spray shape obtained by ejecting the liquid fuel)
Oda, T. et al. Nippon Kikai Gakkai Ronhunshu, B-hen, 1997, 63, (615), 3764-3769. (In Japanese) In an attempt to elucidate the disintegrating process of the spray, a liquid fuel (kerosene) jet was ejected across high-temperature and a high-speed airstream. All tests were performed at an airstream velocity of 30-80 m/s and a temperature of 300-900 K. Scattered-light photographs with a long exposure time were taken to obtain spray shapes. Short exposure photographs were used to obtain detail of the spray near the injector. Although the effect of parameter, the momentum flux ratio of ejecting liquid to airstream, on the height of the spray outer line could be explained for the room temperature airstream, it could not be explained for the hightemperature as follows. Height of the spray outer line increases with the temperature of the airstream under the condition of the same momentum flux ratio and decreases with airstream velocity under the condition of the same momentum flux ratio. Height of the outer line hardly changed when the airstream temperature increased from SO0 K to 900 K under the condition of the same ratio of the mass flow rate of airstream to ejected fuel.
Characteristics of disintegration of jet across a high-temperature and high-steed airstream (2nd report, controlling the distribution of liquid fuel and combustion by means of a bubbling fuel liquid jet)
98103151
Oda, T. et al. Nippon Kikai Gakkai Ronhunshu, B-hen, 1997, 63, (615), 3770-3774. (In Japanese) In order to control the spray shape and temperature of the airstream under an airstream velocity of 80 m/s and a constant ejecting pressure, a bubbling liquid fuel (kerosene) jet was ejected in a normal to high-temperature and high-speed airstream. Spray shapes were obtained by taking scatter-light photographs with a long exposure time, the flame photographs were taken in the downstream region of the flame holder the temperature of the airstream was measured at the exit of the test section of the wind tunnel. The results are presented.
Clean and efficient combustion of simulated low98/03152 calorific-value gases in swirl burner/furnace systems
Fick, W. et al. J. Inst. Energy, March 1998, 71, 12-20. The performance of a large swirl burner/furnace system is examined in terms of its ability to burn simulated gases of very low calorific value efficiently. Previous work has demonstrated that the combustion behaviour and temperature levels produced by waste gas from production of carbon black can be simulated approximately by mixtures of natural gas diluted with substantial amounts of excess air. The system comprises a 2 MW swirl burner/furnace system that can be operated either non-premixed with axial fuel injection on the centreline, or piloted-premixed with up to 60% of the natural gas introduced axially on the centre line in order to pilot the flame and enable the flame detector to monitor the flame front. The results are discussed in terms of the system aerodynamics and, in particular, the influence of coherent structures on the flame stabilization process, temperature, power, excess air levels, mode of fuel entry and emissions of NO, and CO. In particular it is shown that gases of very low calorific value can be efficiently burnt when small amounts of piloting or support fuel are introduced axially on the centre line. Although very low NO, emission levels can be achieved with premixed or simulated low-CV gas consumption, some penalty accrues in terms of CO emission levels-which are typically around 150 ppm as distinct from 50 ppm with non-premixed combustion or for simulated low-CV gases. This probably arises from the very low power
98/03153
Coal combustion research in CSIRO
98/03154
Coal science impact on combustion technology
Weright, J. W. Proc. Annu. Int. Pittsburgh Coal Conf., 1996, 13, (I), 637642. Australia’s leading research organization, CSIRO (Commonwealth Scientific and Industrial Research Organization) contains the Division of Coal and Energy Technology. History and general information about research at CSIRO are given. Coal research in relation to combustion and pyrolysis, gasification, coal minerals, and environmental implications of coal combustion are described.
Beer, J. M. DGMK Tagungsber., 1997, 9702, (Proceedings ICCS ‘97, Volume l), 19-23. The paper reviews selected research works on the combustion process of coal, pollutant release control, fly ash utilization in cement manufacturing and the transformation of mineral matter during coal combustion.
99lo3155
Combustibility of coal for power plants
Zheng, M. and Yao, B. Ranliao Huaxue Xuebao. 1996, 24, (6). 565-570. (In Chinese) For five typical coals for power stations with volatile matter from about 20 to 40%, combustibility curves, characteristic temperatures and kinetic parameters were obtained by ordinary analysis and thermogravimetry analysis techniques. 95103156 Combustion behavior of oxidized coals Rincon, .I. M. et al. DGMK Tugungsber., 1997, 9702, (Proceedings ICCS ‘97, Volume l), 313-316. Coal combustion behaviour was investigated to find out the influence of pre-oxidation. Three bituminous coals were demineralized. The oxidation isotherms at 180, 200, and 230°C were monitored during 24 h and the burning profiles were recorded. The oxygen chemisorption kinetics were studied and the activation energy was estimated to be 70-93 kJ/mol. The mineral matter and the moiety of oxidized coal improve the combustibility properties of coal.
95lo3157 Comprehensive modelling of pulverized coal combustion in a vortex combustor
Zhang, J. and Nieh, S. Fuel, 1997, 76, (2) 123-131. A comprehensive numerical modelling is introduced for the strongly swirling gas-particle turbulent flow and pulverized coal combustion in a recently developed vortex comhustor (VC) for commercial heating applications. A comprehensive two-dimensional coal combustion model was developed which incorporates a new algebraic Reynolds stress turbulence model (ASM). The numerical results for an 88 kW coal fired VC describe the detailed characteristics of the gas-particle flow and combustion in terms of gas velocities, turbulence quantities, temperature, species concentrations, particle density, trajectories, burnout time and residence time. All of these are important to the design and operation of the VC. 9am3i
58 The computation of particle Eulerian models of coal combustion
size in Eulerian-
Fueyo, N. et al. Int. J. Multiphase Flow, 1997, 23, (3). 607-612. The average particle size in the framework of an Eulerian model can be calculated by the method presented here, with allowance for the size diminution due to mass transfer and for a phenomenological representation of other mechanisms which may cause a particle-size change. The method is first validated by comparison with the case which has an analysis solution and then it is applied, in combination with an Eulerian-Eulerian model of coal combustion, to an actual power production boiler. The EulerianEulerian models of coal combustion can be supplied with a method which allows the calculation of the evolution of the mean particle size. The effects of burnout in size diminution and of volatilization in particle swelling and fragmentation is shown. The method can be incorporated further models of particle size evolution.
Computer-aided study on the influence of catalysts 9#03159 on coal combustion property. (IV). Catalytic influence and the mechanics of transition metal oxides and salts catalysts on coal combustion Wu, Z.-h. et al. Jisuanji Yu Yingyong Huaxue, 1998, 15, (1). 49-52 (In Chinese) Typically, ignition temperature measurements are used to study the effects of various catalysts on coal combustion properties. However, in this paper, gas componentsanalysis with gas chromatography is used to examine the influence and mechanisms of transition metal oxides and salts on coal combustion properties. The results show that some of the catalysts have activities on the homogeneous combustion, lowering the ignition temperature, and/or the heterogeneous combustion, promoting the carbon oxidation.
Fuel and Energy Abstracts
July 1999 291