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Survey of biomass cofiring experience in the US
09 Combustion (burners, combustion systems) of interest were fir bark and agricultural waste, fir bark and plastic waste, and forest residue. Deposits were collected on superheater tube simulators with controlled surface temperatures. Kaolin (hydrous 40:60 wt% A1203 SiO2) sharply decreased the tendency of CI to bind in the deposits at high metal temperatures. Minimum kaolin dosage needed to decrease the CI concentration in deposits collected at 500°C to the same level as in the main fuel (fir bark) was 30-50 wt% of the mass flow of the fuel ash. Kaolin did not prevent CI from depositing at probe temperature of 400°C, where high-temperature corrosion is not a problem. The presence of other elements in the kaolin (e.g. Fe and Ca) increased the required dosage.
02/02118 Repowering lignite fuelled boiler plant for high efficiency Mclntosh, M. J. Proc. Int. Conf. Fluid. B e d Combust., 2001, (16), 477488. By the mechanical thermal expression (MTE) process, that had allow energy requirement and used low-grade heat it was possible to reduce the moisture of lignite. This dried lignite, fired in a power plant, increased the efficiency of the plant by about 17% and reduced the greenhouse gas emission by about 14%. In a second technology the gasification of the lignite was performed, and the resulting fuel gas was used in a gas turbine to produce power. This process increased the efficiency of the existing plant by 29-36% and reduced the greenhouse gas emission by 22-26% without predrying of the lignite.
02/02119 Study on fluidized region of particles using direct simulation method Yuan, Z. Ranshao Kexue Yu Jishu, 2001, 7, (2), 120-122. (In Chinese) Since fluidized bed boilers have the advantages of high combustion efficiency and low environmental pollution, developing fluidized bed boilers has received extensive attention. The physical properties of desulphurizing materials are usually different from coal-particles in diameter and density In order to desulphurization efficiently and economically, it is significant to study the fluidized region of bed materials with different diameters and densities. In this paper, the fluidized regions of particles with different diameters and densities were studied using the direct numerical simulation method, and relevant conclusions were drawn out.
02/02120 Study on visualization simulation of 3-D combustion temperature profiles of large boiler furnace Zhou, H. et al. Proc. - Annu. Int. Pittsburgh Coal Conf., 2000, (17), 2050-2058. A method of 3-D combustion temperature profiles of large boiler furnace has been structured using flame image monitor device to examine the distribution of image information of furnace combustion radiative energy, based on the analysis of the principle of radiative energy transfer and the image processing. In the analysis of the radiative energy image processing of the image device, the author suggested a method decomposing the total radiative energy to direct and indirect part, then using Monte Carlo method to calculate. The method can efficiently process the non-uniformly absorbing and isotropic scattering characteristic of coal burning boiler medium, and satisfy the requirement of the visualization of temperature profiles of coal burning boiler. Considering measurement error, least-square procedure was used with prior error to solve 3-D temperature profiles from radiative energy image information. The results of simulating calculation show that when the measurement error is less than 5%, the distribution characteristics (the position of high temperature area and temperature level) of 3-D temperature profiles can still be reconstructed well. It is shown that the method is practicable.
02/02121
Survey of biomass cofiring experience in the US
Battista, J. J. and Hughes, E. E. Proceedings - Annual International Pittsburgh Coal Cot~ference, 2000, (17), 1442-1451. Since 1992, and together with TVA, other utility companies and the Department of Energy (DOE), EPRI has conducted a research and field testing programme on biomass cofiring in utility boilers. Tests in over 10 boilers have been carried out as part of that programme. EPRI was aware of other tests that were not part of the EPRI-related programme and were performed at various times, both before 1992 and during the years of the EPRI programme. In order to obtain information on these other tests and to summarize results both within and outside of the EPRI programme, EPRI with support from DOE is performing a survey of persons and companies with knowledge of biomass cofiring tests and their results. This paper presents some findings from that survey. A total of over 20 and perhaps over 30 such tests may potentially be documented. In general such tests have revealed that biomass, usually wood-derived fuels, can be co-fired at over 10% of the heat input. In performing the survey, EPRI sought to document the time, place, amount co-fired, duration, parties involved, boiler and burner types, blended versus separated as the feeding approach, and the results observed or measured.
274
Fuel and Energy Abstracts July 2002
02/02122 The design and experiment of 25 t/h double circulating fluidized bed boiler Wu, Z. et al. Proeeedings o f the International Conference on Fluidi:ed Bed Combustion, 2001, (t6), 751-755. This paper describes the design and experiment of 25t/h double circulating fluidized bed (DCFB) boiler. The National Laboratory of Coal Combustion in Huazhong University of Science and Technology has developed the new type of 25t/h DCFB boiler. The DCFB boiler can run steadily and reach the design steam capacity. By the two-stage separators, the DCFB boiler overcomes the problem of abrasion in normal CFB boiler. This type of boiler can be used to not only build a new boiler, but also retrofit the chain boiler with the double drums into circulating fluidized bed boiler.
02/02123 The study on spray dryer absorber flue gas desulfurization for industrial boiler Wang, F. and Lu, M. Proc. - Annu. Int. Pittsburgh Coal Conl(., 2000, (17), 1148-1153. The spray dryer absorber for flue gas desulphurization was first adopted in China in 1980's. Since it has the advantages of high efficiency and low investment, it showed a potential cleaner in flue gas desulphurization. But because it mostly used Calcium Hydroxide (Ca(OH)z) solution as desulphurizing agent, thus brought about problems such as conglomerating of reagent and clogging the spray nozzles. To eliminate these problems, special reagents had to be studied. Pilot tests by spray dryer absorber system for treating 10000 m3/h flue gas had been done with three types of spray nozzles and four kinds of desulphurizing agents. Test results showed that with sodium hydroxide as desulphurizing agent, cleaning efficiency could be steady at 60,.~69.7%, and 79% of desulphurization efficiency could be achieved if the cleaning agent were increased. This type of equipment for treating 10000 m3/b flue gas was adopted by four companies,
02/02124
Treatment of brown coal for firing of boilers
Lenz, U. et al. Ger. DE 10,006,613 (CI. F23KI/00), 22 Nov 2001, Appl. 10,006,613, 15 Feb 2000. 4. (In German) A brown coal feed for boilers is subjected to multistage size reduction and drying to obtain an average particle size of <1 ram. After >1 size reduction stage, magnetic and/or electrostatic separation of Fe minerals (especially siderite) is carried out to increase the melting point of ash and decrease slag formation during combustion. The separation is done at least in fractions having a middle particle size in which the siderite enrichment is maximum The Fe content is decreased below 5000 ppm.
02/02125 Use of steam-gas ejector for improvement of capacity and explosion safety of pulverization systems in thermal power plants Klochenko, V. S. and Karamanyan, A. K. Energetika i Elektrif.ikatsiya, 2001, (5), 16-20. (In Russian) AT 'VIPOL'. A steam ejector is used to increase the drying capacity of the pulverization unit of a utility boiler. It increases the volume of flue gases drawn from the boiler's convection zone by 30% and decreases explosion hazard.
09
COMBUSTION Burners, combustion systems
02/02126 A CFD-based study of the mixing processes during reburning Zarnescu, V. and Pisupati, S. V. Proceedings - Annual International Pittsburgh Coal Conference, 2000, (17), 234-258. The current study is part of a broader investigation, which deals with the application of a novel concept of integrated design to combustor modelling using CFD methods. The main objective is the reduction of NOx emissions. The current work studies the impact of mixing optimization and mixing model on NOx reduction during re-burning. Numerical simulations of the re-burning process are conducted on a pilot-scale 0.5 MM Btu/h down-fired combustor (DFC) and compared with experimental data. Optimized mixing conditions resulted in a significant reduction in NO× levels. A 're-burn calculator' including the TSL mixing model is used for predicting the NOx emissions in the DFC and the results are compared with quality and quantity CFD-based simulations. Modelling results showed that for this case mixing is dominant over the chemical, and hence the use of an advanced fluid
02/02118 Repowering lignite fuelled boiler plant for high efficiency Mclntosh, M. J. Proc. Int. Conf. Fluid. B e d Combust., 2001, (16), 477488. By the mechanical thermal expression (MTE) process, that had allow energy requirement and used low-grade heat it was possible to reduce the moisture of lignite. This dried lignite, fired in a power plant, increased the efficiency of the plant by about 17% and reduced the greenhouse gas emission by about 14%. In a second technology the gasification of the lignite was performed, and the resulting fuel gas was used in a gas turbine to produce power. This process increased the efficiency of the existing plant by 29-36% and reduced the greenhouse gas emission by 22-26% without predrying of the lignite.
02/02119 Study on fluidized region of particles using direct simulation method Yuan, Z. Ranshao Kexue Yu Jishu, 2001, 7, (2), 120-122. (In Chinese) Since fluidized bed boilers have the advantages of high combustion efficiency and low environmental pollution, developing fluidized bed boilers has received extensive attention. The physical properties of desulphurizing materials are usually different from coal-particles in diameter and density In order to desulphurization efficiently and economically, it is significant to study the fluidized region of bed materials with different diameters and densities. In this paper, the fluidized regions of particles with different diameters and densities were studied using the direct numerical simulation method, and relevant conclusions were drawn out.
02/02120 Study on visualization simulation of 3-D combustion temperature profiles of large boiler furnace Zhou, H. et al. Proc. - Annu. Int. Pittsburgh Coal Conf., 2000, (17), 2050-2058. A method of 3-D combustion temperature profiles of large boiler furnace has been structured using flame image monitor device to examine the distribution of image information of furnace combustion radiative energy, based on the analysis of the principle of radiative energy transfer and the image processing. In the analysis of the radiative energy image processing of the image device, the author suggested a method decomposing the total radiative energy to direct and indirect part, then using Monte Carlo method to calculate. The method can efficiently process the non-uniformly absorbing and isotropic scattering characteristic of coal burning boiler medium, and satisfy the requirement of the visualization of temperature profiles of coal burning boiler. Considering measurement error, least-square procedure was used with prior error to solve 3-D temperature profiles from radiative energy image information. The results of simulating calculation show that when the measurement error is less than 5%, the distribution characteristics (the position of high temperature area and temperature level) of 3-D temperature profiles can still be reconstructed well. It is shown that the method is practicable.
02/02121
Survey of biomass cofiring experience in the US
Battista, J. J. and Hughes, E. E. Proceedings - Annual International Pittsburgh Coal Cot~ference, 2000, (17), 1442-1451. Since 1992, and together with TVA, other utility companies and the Department of Energy (DOE), EPRI has conducted a research and field testing programme on biomass cofiring in utility boilers. Tests in over 10 boilers have been carried out as part of that programme. EPRI was aware of other tests that were not part of the EPRI-related programme and were performed at various times, both before 1992 and during the years of the EPRI programme. In order to obtain information on these other tests and to summarize results both within and outside of the EPRI programme, EPRI with support from DOE is performing a survey of persons and companies with knowledge of biomass cofiring tests and their results. This paper presents some findings from that survey. A total of over 20 and perhaps over 30 such tests may potentially be documented. In general such tests have revealed that biomass, usually wood-derived fuels, can be co-fired at over 10% of the heat input. In performing the survey, EPRI sought to document the time, place, amount co-fired, duration, parties involved, boiler and burner types, blended versus separated as the feeding approach, and the results observed or measured.
274
Fuel and Energy Abstracts July 2002
02/02122 The design and experiment of 25 t/h double circulating fluidized bed boiler Wu, Z. et al. Proeeedings o f the International Conference on Fluidi:ed Bed Combustion, 2001, (t6), 751-755. This paper describes the design and experiment of 25t/h double circulating fluidized bed (DCFB) boiler. The National Laboratory of Coal Combustion in Huazhong University of Science and Technology has developed the new type of 25t/h DCFB boiler. The DCFB boiler can run steadily and reach the design steam capacity. By the two-stage separators, the DCFB boiler overcomes the problem of abrasion in normal CFB boiler. This type of boiler can be used to not only build a new boiler, but also retrofit the chain boiler with the double drums into circulating fluidized bed boiler.
02/02123 The study on spray dryer absorber flue gas desulfurization for industrial boiler Wang, F. and Lu, M. Proc. - Annu. Int. Pittsburgh Coal Conl(., 2000, (17), 1148-1153. The spray dryer absorber for flue gas desulphurization was first adopted in China in 1980's. Since it has the advantages of high efficiency and low investment, it showed a potential cleaner in flue gas desulphurization. But because it mostly used Calcium Hydroxide (Ca(OH)z) solution as desulphurizing agent, thus brought about problems such as conglomerating of reagent and clogging the spray nozzles. To eliminate these problems, special reagents had to be studied. Pilot tests by spray dryer absorber system for treating 10000 m3/h flue gas had been done with three types of spray nozzles and four kinds of desulphurizing agents. Test results showed that with sodium hydroxide as desulphurizing agent, cleaning efficiency could be steady at 60,.~69.7%, and 79% of desulphurization efficiency could be achieved if the cleaning agent were increased. This type of equipment for treating 10000 m3/b flue gas was adopted by four companies,
02/02124
Treatment of brown coal for firing of boilers
Lenz, U. et al. Ger. DE 10,006,613 (CI. F23KI/00), 22 Nov 2001, Appl. 10,006,613, 15 Feb 2000. 4. (In German) A brown coal feed for boilers is subjected to multistage size reduction and drying to obtain an average particle size of <1 ram. After >1 size reduction stage, magnetic and/or electrostatic separation of Fe minerals (especially siderite) is carried out to increase the melting point of ash and decrease slag formation during combustion. The separation is done at least in fractions having a middle particle size in which the siderite enrichment is maximum The Fe content is decreased below 5000 ppm.
02/02125 Use of steam-gas ejector for improvement of capacity and explosion safety of pulverization systems in thermal power plants Klochenko, V. S. and Karamanyan, A. K. Energetika i Elektrif.ikatsiya, 2001, (5), 16-20. (In Russian) AT 'VIPOL'. A steam ejector is used to increase the drying capacity of the pulverization unit of a utility boiler. It increases the volume of flue gases drawn from the boiler's convection zone by 30% and decreases explosion hazard.
09
COMBUSTION Burners, combustion systems
02/02126 A CFD-based study of the mixing processes during reburning Zarnescu, V. and Pisupati, S. V. Proceedings - Annual International Pittsburgh Coal Conference, 2000, (17), 234-258. The current study is part of a broader investigation, which deals with the application of a novel concept of integrated design to combustor modelling using CFD methods. The main objective is the reduction of NOx emissions. The current work studies the impact of mixing optimization and mixing model on NOx reduction during re-burning. Numerical simulations of the re-burning process are conducted on a pilot-scale 0.5 MM Btu/h down-fired combustor (DFC) and compared with experimental data. Optimized mixing conditions resulted in a significant reduction in NO× levels. A 're-burn calculator' including the TSL mixing model is used for predicting the NOx emissions in the DFC and the results are compared with quality and quantity CFD-based simulations. Modelling results showed that for this case mixing is dominant over the chemical, and hence the use of an advanced fluid