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03998 Diesel coal combined cycle
09
Combustion
(burners, combustion
systems)
Combustion performance characteristics of fine 97103993 grind fuels Chow, 0. K and Levasseur. A. A. Proc. Int. Tech. Conf. Coal Util. Fuel Syst., 1996, 21, 327-33X. Finer grind fuels improved the combustion and carbon conversion of Pittsburgh No. 8 coal at both unstaged and staged firing conditions. Improvements in furnace slagging, deposit cleanability by soot blowing, and heat flux recoveries were ohserved. Designing, installing and operating low NO, com97103994 bustion systems in power plants Lazzeri. L. and De Santis, R. Proc. Am. Power Conf., 1997, 59, (2) 11411150. Innovative technologies for ‘in furnace’ NO, control have been developed by Ansaldo Energia, in strict co-operation with the Italian Electricity Board (ENEL), The methods, applied both in Italy and abroad, on all types of boilers >20 MWe and for different fuels contain innovative low NO, burners (LNB) and optimized air and fuel staging techniques. Eighty-five per cent NO, reductions have been obtained with no significant impact on boiler efficiency. Techniques employed and operating examples are provided. Desulfurization of coal by co-firing it with EVA co97103995 polymer waste in a fluidized bed combustor Sulaiman, M. R. and Cliffe, K. R. Jubilee Res. Event, Two-Day Symp., 1997, 1, 9-12. Ethylene Vinyl Acetate (EVA) co-polymer waste generated from the footwear industry in Malaysia amounts to 18000 tonnes per year. Despite having reasonably high calorific values, this is reduced in the product used for making shoes by the addition of fillers and additives. The major filler which amounts to 40% of the product is calcium carbonate which is used in fluidized bed combustors to remove sulfur from coal. In this project, EVA waste was co-fired with a high sulfur Spanish Lignite to examine the potential of this polymer waste for sulfur removal from coal. A specially designed fluidized bed combustor 15 cm diameter and 120 cm high was constructed for the tests. Results shows that the sulfur dioxide emissions can he reduced significantly depending on coal size, EVA-to-coal ratio and residence time. Development and impkmematfon of hybrid fluidii bed 97/03996 combustion Karoly, R. Energiagazdalkodos, 1997, 38, (4) 147-148. (In Hungary)“,4> The development of low NO. burners under the IEA 97103997 coal combustion sciences agreement Whaley, H. Proc. Am. Power Conf., 1997, 59, (2) 1136-1140. The International Energy Agency ( IEA) has been implementing agreement on coal combustion sciences since 1985. There are two operating annexes, the first, Annex I is task-shared; designated research projects within the participating countries are reported on an annual basis. Annex II is costshared; research is conducted at the International Flame Research Foundation (IFRF) in the Netherlands and paid for by the participants, Canada, Germany, the Netherlands and the UK. The objectives of Annex II are to develop advanced low NO, coal burners for power boilers and to characterize their performance with a wide range of coals and coal blends. Two burners have been selected for promising NO, formation suppression, thereby reducing emissions to below regulatory levels. One is an aerodynamically air-staged burner (AASB) and the other an internally fuel-staged burner (IFSB). Both can utilize a single boiler entry port, which makes them ideal for retrofitting. The IFSB, when commercially developed, is anticipated to meet projected Canadian NO, regulations. Diesel coal combined cycle 97103998 Shelor, F. M. et al. Proc. Inf. Tech. Conf. Coal Vtil. Fuel Syst., 1993, 18, 3748.
The authors describe the development of the Diesel Coal Combined Cycle (DCCC). Topics include the performance of an example plant and gas clean-up system, and combustion testing. A unique feature of the DCCC, in contrast to IGCCs, is their high efficiency at in smaller plants. Ecological and economic aspects of coal 97103999 combustion Hycnar, J. J. and Pinko, L. Karbo-Energochemical-Ekol., 1997,42, (1) 3-6. (In Polish). Sulfur dioxide emissions reduction in coal-fired power plants can be achieved in a number of ways. The flue gas desulfurization process is very effective, hut also relatively expensive. In old and small power plants, it is more economical to use a low sulfur coal. The supply of low sulfur coal is limited, it is therefore advisable from a technical and economical point of view, to prepare the coal prior to power plant combustion. The paper gives some relevant points in attaining the required composition of energetic coal for ensuring low sulfur content and high heating value. The system is described and presented.
336
Fuel and Energy Abstracts
September
1997
Effect of burner design on combustion and SHIRH 97/04000 spray performance Nakkeeran, S. ef al. Proc. Int. Tech. Conf. Coal Util. Fuel Syst., 1997, 22. 639-646. Secondary air nozzle design influence on combustion in the furnace and its implication on the performance of the superheat (SH)/reheat (RH) system and its effect on SHiRH spray. The design of coal nozzle assembly and secondary air nozzle has previously undergone several changes to meet varying demands like low load stabilization and NO, emissions control. Trials were conducted in a power station with two units of identical design, with six pulverizers. The chosen unit [tangential] burner assembly consisted of six coal elevations and three fuel oil elevations for start-up and low load stabilization. During the trials, the different nozzle design adopted in one of the units changed the air regime, under the similar operating condition, resulting in a considerable reduction in the SHiRH spray quantities. The details of changes made in the fuel oil nozzle design, other operating conditions during the trials, and the operating results were discussed. 97/04001 Effect of operating parameters on heat transfer in the lean phase region of a CFB riser column Reddy, B. V. and Nag, P. K. Inr. .I. Energy Res., 1997, 21, (IO). 9.11~Y40. The paper investigates the radial variation of the heat transfer coefficient across the bed width, including the effect of fins and fin shapes on the heat transfer characteristics in the lean phase region of a circulating fluidized bed riser column. Three test sections (hare horizontal tube, V-fin tube and square fin tube) were employed for the investigation. The experimental unit consists of a riser column of 102 x 102 mm in bed cross-section, 5.25 m in height with a return leg of the same dimensions, and both made up of Plexiglas columns. For the same operating conditions. the provision of fins results in a drop in heat transfer coefficient, but increases total heat transfer owing to increased surface area. The present experimental data are compared with published literature and good agreement is found. The experimental data also corresponds to the two-zone hydrodynamics of a circulating fluidized bed. 97104002 Effects of mild treatment on the properties of the char product by the flash pyrolysis of Wandoan coal Kishino, M. et al. Nippon Enerugi Gakkaishi, 1997, 76. (5). 405-411. (In Japanese) Flash pyrolysis reactivity of Wandoan coal was investigated with regard to the effects of mild acid and/or tetralin treatments in order to improve the product distribution as well as to modify the properties of the char. The reactivity of Wandoan coal at 590°C for 5 s by Curie-point pyrolyser was improved by hydrogen chloride or acetic acid aqueous/20 vol.% alcohol pretreatment. The char yield was decreased with increased yields of gas and tar. Tetralin impregnation also reduced the char yield to 63.5%. A combination of acid and tetralin pre-treatments reduced the char yield slightly more. The porosity of the pyrolysed char was influenced very much by the acid treatment. The macropores of which areas ranging from 2OS411 pm* were increased significantly by the acetic acid pre-treatment. These results revealed that such acid pre-treatments may enhance the gasification and the volatilization of tar fraction and improved the fusibility of coal to enlarge the porosity. 97104003 An experimental study of combustion of Shen-Mu cws Lifang, C. et al. Proc. Int. Tech. Conf. Coal Util. Fuel Syst., 1993. 18. 651658. The paper studies self-stabilized combustion of Shen-Mu coal-water slurries (CWS). Results show that the Shen-Mu CWS of about 65% concentration possesses good rheological property and is easily atomized. The Sauter mean diameter, of the slurry spray is 56 I’m, while the air/fuel mass ratio is 0.21. The atomizer has excellent atomization performance. Self-stabilized combustion is sustained without heated air or auxiliary fuel. The used is a combustion chamber 360 mm x 540 mm x 1400 mm, and the rates of CWS flow is 320 kg/h. 97104004 Experimental study on rapid combustion of oil shale particles under elevated pressure Li, S. and Wang, J. Shiyou Daxue Xuebao, Ziran Kexueban, 1996, 20, (Suppl.), 73-76. (In Chinese) Fushun and Maoming oil shale particles were subjected to rapid combustion tests in a pressured thermogravimetric analyser for simulating the real combustion behaviour in fluidized bed boiler. The effects of particle diameter, temperature and pressure on combustion were studied. The oil shale samples with the diameters of 3-11 mm were used and the combustion conversions vs time at the temperature of 700-9000°C and the pressure of 0.1-0.9 MPa were obtained. The experimental data fit the first order reaction model, and the kinetic parameters were obtained. Gas concentration profiles and NO, formation in 97104005 circulating fluidized bed combustion Zhao, J. et al. Fuel, 1997, 76, (9), 853-860. In order to better understand the competing NO, formation and destruction reactions in circulating fluidized bed combustion, an experimental study was undertaken. Both longitudinal and lateral gradients were measured for NO,, Oz, CO and CH, during combustion of solid fuels of
Combustion
(burners, combustion
systems)
Combustion performance characteristics of fine 97103993 grind fuels Chow, 0. K and Levasseur. A. A. Proc. Int. Tech. Conf. Coal Util. Fuel Syst., 1996, 21, 327-33X. Finer grind fuels improved the combustion and carbon conversion of Pittsburgh No. 8 coal at both unstaged and staged firing conditions. Improvements in furnace slagging, deposit cleanability by soot blowing, and heat flux recoveries were ohserved. Designing, installing and operating low NO, com97103994 bustion systems in power plants Lazzeri. L. and De Santis, R. Proc. Am. Power Conf., 1997, 59, (2) 11411150. Innovative technologies for ‘in furnace’ NO, control have been developed by Ansaldo Energia, in strict co-operation with the Italian Electricity Board (ENEL), The methods, applied both in Italy and abroad, on all types of boilers >20 MWe and for different fuels contain innovative low NO, burners (LNB) and optimized air and fuel staging techniques. Eighty-five per cent NO, reductions have been obtained with no significant impact on boiler efficiency. Techniques employed and operating examples are provided. Desulfurization of coal by co-firing it with EVA co97103995 polymer waste in a fluidized bed combustor Sulaiman, M. R. and Cliffe, K. R. Jubilee Res. Event, Two-Day Symp., 1997, 1, 9-12. Ethylene Vinyl Acetate (EVA) co-polymer waste generated from the footwear industry in Malaysia amounts to 18000 tonnes per year. Despite having reasonably high calorific values, this is reduced in the product used for making shoes by the addition of fillers and additives. The major filler which amounts to 40% of the product is calcium carbonate which is used in fluidized bed combustors to remove sulfur from coal. In this project, EVA waste was co-fired with a high sulfur Spanish Lignite to examine the potential of this polymer waste for sulfur removal from coal. A specially designed fluidized bed combustor 15 cm diameter and 120 cm high was constructed for the tests. Results shows that the sulfur dioxide emissions can he reduced significantly depending on coal size, EVA-to-coal ratio and residence time. Development and impkmematfon of hybrid fluidii bed 97/03996 combustion Karoly, R. Energiagazdalkodos, 1997, 38, (4) 147-148. (In Hungary)“,4> The development of low NO. burners under the IEA 97103997 coal combustion sciences agreement Whaley, H. Proc. Am. Power Conf., 1997, 59, (2) 1136-1140. The International Energy Agency ( IEA) has been implementing agreement on coal combustion sciences since 1985. There are two operating annexes, the first, Annex I is task-shared; designated research projects within the participating countries are reported on an annual basis. Annex II is costshared; research is conducted at the International Flame Research Foundation (IFRF) in the Netherlands and paid for by the participants, Canada, Germany, the Netherlands and the UK. The objectives of Annex II are to develop advanced low NO, coal burners for power boilers and to characterize their performance with a wide range of coals and coal blends. Two burners have been selected for promising NO, formation suppression, thereby reducing emissions to below regulatory levels. One is an aerodynamically air-staged burner (AASB) and the other an internally fuel-staged burner (IFSB). Both can utilize a single boiler entry port, which makes them ideal for retrofitting. The IFSB, when commercially developed, is anticipated to meet projected Canadian NO, regulations. Diesel coal combined cycle 97103998 Shelor, F. M. et al. Proc. Inf. Tech. Conf. Coal Vtil. Fuel Syst., 1993, 18, 3748.
The authors describe the development of the Diesel Coal Combined Cycle (DCCC). Topics include the performance of an example plant and gas clean-up system, and combustion testing. A unique feature of the DCCC, in contrast to IGCCs, is their high efficiency at in smaller plants. Ecological and economic aspects of coal 97103999 combustion Hycnar, J. J. and Pinko, L. Karbo-Energochemical-Ekol., 1997,42, (1) 3-6. (In Polish). Sulfur dioxide emissions reduction in coal-fired power plants can be achieved in a number of ways. The flue gas desulfurization process is very effective, hut also relatively expensive. In old and small power plants, it is more economical to use a low sulfur coal. The supply of low sulfur coal is limited, it is therefore advisable from a technical and economical point of view, to prepare the coal prior to power plant combustion. The paper gives some relevant points in attaining the required composition of energetic coal for ensuring low sulfur content and high heating value. The system is described and presented.
336
Fuel and Energy Abstracts
September
1997
Effect of burner design on combustion and SHIRH 97/04000 spray performance Nakkeeran, S. ef al. Proc. Int. Tech. Conf. Coal Util. Fuel Syst., 1997, 22. 639-646. Secondary air nozzle design influence on combustion in the furnace and its implication on the performance of the superheat (SH)/reheat (RH) system and its effect on SHiRH spray. The design of coal nozzle assembly and secondary air nozzle has previously undergone several changes to meet varying demands like low load stabilization and NO, emissions control. Trials were conducted in a power station with two units of identical design, with six pulverizers. The chosen unit [tangential] burner assembly consisted of six coal elevations and three fuel oil elevations for start-up and low load stabilization. During the trials, the different nozzle design adopted in one of the units changed the air regime, under the similar operating condition, resulting in a considerable reduction in the SHiRH spray quantities. The details of changes made in the fuel oil nozzle design, other operating conditions during the trials, and the operating results were discussed. 97/04001 Effect of operating parameters on heat transfer in the lean phase region of a CFB riser column Reddy, B. V. and Nag, P. K. Inr. .I. Energy Res., 1997, 21, (IO). 9.11~Y40. The paper investigates the radial variation of the heat transfer coefficient across the bed width, including the effect of fins and fin shapes on the heat transfer characteristics in the lean phase region of a circulating fluidized bed riser column. Three test sections (hare horizontal tube, V-fin tube and square fin tube) were employed for the investigation. The experimental unit consists of a riser column of 102 x 102 mm in bed cross-section, 5.25 m in height with a return leg of the same dimensions, and both made up of Plexiglas columns. For the same operating conditions. the provision of fins results in a drop in heat transfer coefficient, but increases total heat transfer owing to increased surface area. The present experimental data are compared with published literature and good agreement is found. The experimental data also corresponds to the two-zone hydrodynamics of a circulating fluidized bed. 97104002 Effects of mild treatment on the properties of the char product by the flash pyrolysis of Wandoan coal Kishino, M. et al. Nippon Enerugi Gakkaishi, 1997, 76. (5). 405-411. (In Japanese) Flash pyrolysis reactivity of Wandoan coal was investigated with regard to the effects of mild acid and/or tetralin treatments in order to improve the product distribution as well as to modify the properties of the char. The reactivity of Wandoan coal at 590°C for 5 s by Curie-point pyrolyser was improved by hydrogen chloride or acetic acid aqueous/20 vol.% alcohol pretreatment. The char yield was decreased with increased yields of gas and tar. Tetralin impregnation also reduced the char yield to 63.5%. A combination of acid and tetralin pre-treatments reduced the char yield slightly more. The porosity of the pyrolysed char was influenced very much by the acid treatment. The macropores of which areas ranging from 2OS411 pm* were increased significantly by the acetic acid pre-treatment. These results revealed that such acid pre-treatments may enhance the gasification and the volatilization of tar fraction and improved the fusibility of coal to enlarge the porosity. 97104003 An experimental study of combustion of Shen-Mu cws Lifang, C. et al. Proc. Int. Tech. Conf. Coal Util. Fuel Syst., 1993. 18. 651658. The paper studies self-stabilized combustion of Shen-Mu coal-water slurries (CWS). Results show that the Shen-Mu CWS of about 65% concentration possesses good rheological property and is easily atomized. The Sauter mean diameter, of the slurry spray is 56 I’m, while the air/fuel mass ratio is 0.21. The atomizer has excellent atomization performance. Self-stabilized combustion is sustained without heated air or auxiliary fuel. The used is a combustion chamber 360 mm x 540 mm x 1400 mm, and the rates of CWS flow is 320 kg/h. 97104004 Experimental study on rapid combustion of oil shale particles under elevated pressure Li, S. and Wang, J. Shiyou Daxue Xuebao, Ziran Kexueban, 1996, 20, (Suppl.), 73-76. (In Chinese) Fushun and Maoming oil shale particles were subjected to rapid combustion tests in a pressured thermogravimetric analyser for simulating the real combustion behaviour in fluidized bed boiler. The effects of particle diameter, temperature and pressure on combustion were studied. The oil shale samples with the diameters of 3-11 mm were used and the combustion conversions vs time at the temperature of 700-9000°C and the pressure of 0.1-0.9 MPa were obtained. The experimental data fit the first order reaction model, and the kinetic parameters were obtained. Gas concentration profiles and NO, formation in 97104005 circulating fluidized bed combustion Zhao, J. et al. Fuel, 1997, 76, (9), 853-860. In order to better understand the competing NO, formation and destruction reactions in circulating fluidized bed combustion, an experimental study was undertaken. Both longitudinal and lateral gradients were measured for NO,, Oz, CO and CH, during combustion of solid fuels of