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03965 Cofiring wood waste in utility boilers: results of parametric testing and engineering evaluations
08
Boiler tuning using SPO at Detroit Edison’s River 98103961 Rouge Plant for best economic performance while minimizing NO. emissions
Haman, R. L. et al. FACT, 1996, 21, (Proceedings of the International Joint Power Generation Conference, Volume 1: Environmental Control/ Fuels and Combustion Technologies, 1996) l-8. In order to comply with the Clean Air Act Amendments of 1990 (CAAA), as well as to preparation for a more competitive business environment, a growing number of utilities arc including boiler tuning in strategies. Combustion tuning (optimization) is a logical first step in meeting both these challenges. Provided by Ultramax Corporation and EPRI, a technology based on sequential process optimization (SPO), is being used as a cost-effective tool to gain improvements prior to decisions for capitalintensive solutions. Called the ULTRAMAX” Method, this empirical method of optimization is capable of determining the best boiler capabilities and help delay, or even avoid, expensive retrofits or repowering. SPO can serve as a least-cost way to attain the right degree of compliance with current and future phases of CAAA. Tuning ensures a staged strategy to stay ahead of emissions regulations, but not so far ahead as to cause regret for taking actions that ultimately are not mandated or warranted. Detroit Edison is a large utility investigating SPO as a tool to lower NO, emissions and optimize boiler performance. The company has applied SPO to tune two coal-fired units at its River Rouge Power Plant to evaluate the technology for possible system-wide usage. Following the successful demonstration in reducing NO, from these units, SPO is being considered for use in other Detroit Edison fossil-fired plants. Tuning first will be used as a least-cost option to drive NO, to its lowest level with operating adjustment. In addition, optimization shows the true capability of the units and the margins available when the Phase II rules become effective in 2000. A case study of the second tuning process is given with a discussion of the opportunities offered by the technology.
Boiler with gravity circulating bed for co-generation 98103962 of coal gas and steam Zhang, X. and Cheng, Y. Faming Zhuanli Shenqing Gongkai Shuomingshu CN 1,144,260 (Cl. ClOJ3/80), 5 Mar 1997, Appt. 95108,875, 1 Sep 1995, 8 pp. (In Chinese) A fluidized bed in the lower portion of the boiler comprises three parallel beds: (1) a combustion bed; (2) a heat-transfer bed; and (3) a gasification bed, with submerged orifices arranged between them. By strengthening the gravity recirculation of fly ashes inside the furnace, the amount of ash recirculation increases, making effective use of the heat source and thus the gas output of the boiler improves with increasing temperature.
Characterization of coal with respect to carbon 98103963 burnout in pulverized coal-fired boilers Cloke, M. er al. Fuel, 1997, 76, (13) 1257-1267. Measured as percentage combustibles remaining, carbon burnout was determined for 16 world coals on a 1 MW pulverized coal combustion rig. The combustibles-remaining figures were correlated with parameters such as ash yield, carbon content, fuel ratio, rank, reactive macerals content and a reactivity parameter determined from a gray-scale histogram obtained by image analysis of the coals. The correlation of the reactivity parameter with the combustibles remaining was far superior to that given by any other parameter. Char samples collected at various points in the combustion rig confirmed that the intrinsic reactivity of char decreases during the combustion process and that the morphology of the char produced during the very early stages of combustion has a much greater effect than intrinsic reactivity on carbon burnout. !3:;3:;64
Co-firing switchgrass in a 50 MW pulverized coal
Regland, K. W. et al. Bioenergy ‘96, Proc. Natl. BioenergV Conf., 7th. 1996, 1, 113-120. Co-firing of switchgrass with pulverized coal took place in a 50 MW wallfired, radiant boiler generating station. Shredded switchgrass was fed to a hammermill onto a live bottom storage bunker. The switchgrass was moved onto a belt conveyor, via twin screw augers, which leads to a rotary air lack valve and through a pressurized pipe to the boiler where it is injected into the furnace at two points between first and second level coal burners. The project’s main objective was to evaluate the boiler performance, slagging behaviour and emissions of the co-fired switchgrass at replacement of rates of up to 20% by mass. Fuel handling and feeding, combustion behaviour, boiler response and emissions are favourable according to initial co-firing tests.
Cofiring wood waste in utility boilers: results of parametric testing and engineering evaluations
Steam raising (boiler operation/design)
and the engineering studies have included the influence of co-firing on boiler capacity, efficiency, and emissions such as NO, and SO?. The test results from the Allen Fossil Plant of Tennessee Valley Authority (TVA) and the Shawville Generating Station of GPUiPenelec are reviewed. The paper focuses upon the results of these tests in the context of co-firing test experience. Finally, the paper considers some of the parameters that emerge from co-firing engineering analyses and test programs and overviews some of the ongoing programmes in co-firing.
The combustion aerodynamics of a pulverized coal low NO, swirl burner in an industrial boiler
98lO3966
Sharifi, R. and Scaroni, A. W. FACT, 1996, 21, (Proceedings of the International Joint Power Generation Conference, Volume 1: Environmental Control/Fuels and Combustion Technologies, 1996), 59-66. The application of a Computational Fluid Dynamics (CFD) code (FLUENT) to predict temperature and velocity profiles and particle trajectories in an industrial boiler fired by a low NO, pulverized coal swirl burner is investigated. The code predictions were compared to experimental measurements of gas temperature, particle size distribution and particle velocities. A suction pyrometer and a Particle Counter Sizer Velocimeter Probe (PCSV-P) were employed as the diagnostics. Good agreement was found between the temperature predictions and the measurements. Using the Baum and Street model with a swelling factor of zero, the in situ particle size distributions were accurately predicted. The Type II flow issued from the burner could be transformed into Type III flow, by eliminating swirl from the primary air stream, which provided the preferred particle trajectories and increased the combustion efficiency, as illustrated by the numerical modelling.
98103967 Combustion characteristics pulverized-coal 300 MW. utility boiler
of a front-wall-fired
Costa, M. et al. Cornbust. Sci. Technol., 1997, 129, (l-6), 277-293. The results of an experimental study carried out in a 300 MW,, front-wallfired, pulverized-coal, utility boiler are described. The data reported include local mean gas species concentrations of Oz, CO, COs, NO, and gas temperatures measured at several ports in the boiler including those in the burner region and incident wall heat fluxes taken around the boiler periphery at 39 ports. The incident wall heat fluxes are reported for two boiler operating conditions. A considerable effort was made to assure minimum variations in boiler operating conditions and coal chemistry and particle size characteristics so that the data presented are especially useful for 3-D mathematical model evaluation and development. The findings were that: (i) the boundary air injected below the first row of burners leads to oxidizing conditions close to the back wall; (ii) local gas temperatures and CO concentrations in the boiler, near the burners, reached maximum values of about 1470°C and 1.6%, respectively; (iii) above the boiler nose the measured NO,, concentrations are reasonably uniform with averaged values of about 670 ppm; and (iv) wall radiant heat fluxes present maximum values at the side wall close to the intermediate row of burners.
99/03968 The demonstration of gas reburning technology on a 600 MWe boiler at Longannet, Scotland Macphail, J. M. and Rhine, J. M. Combust. Emiss. Control III, 1997, 340350. Edited by Adams, M., Institute of Energy, London, UK. The progress of the demonstration of gas reburning technology on a 600 MW, coal-fired boiler at Longannet in Scotland, owned and operated by Scottish Power is described. The project involves a partnership of leading European utilities and boiler manufacturers and will he the largest demonstration of the technology in the world. Details of the process design, the specification of the modifications to the boiler, and some of the aspects of the engineering design and installation are discussed. Plans for the testing and optimization of the system are outlined. The resultant plant data will be used to validate the design tools needed to exploit the technology post-demonstration.
9BlO3969 The design and installation of a gas reburn system on a 600 MW coal-fired boiler
Golland, E. S. et al. FACT, 1996, 21, (Proceedings of the International Joint Power Generation Conference, Volume 1: Environmental Control/ Fuels and Combustion Technologies, 1996) 101-109. In order to demonstrate the economic and technical viability of the technology, a gas reburn system with overfire air injection, to reduce NO, emissions was installed on a 600 MW coal-fired boiler. The facility was the Longannet Power Station, at Fife, Scotland. The design and retrofit of existing equipment were described.
Development of an ultra low NO, staged mixing burner for pulverized coal
98/03966
9aio3970
Tillman, D. A. FACT (Am. Sot. Mechanical Eng.), 1996,21, (Proceedings of the International Joint Power Generation Conference, Volume 1: Environmental Control/Fuels and Combustion Technologies, 1996). 455462. Under contract to the Electric Power Research Institute (EPRI), the Foster Wheeler Environmental Corporation has conducted parametric tests and engineering evaluations of co-firing wood waste with both eastern and western coal in cyclone and PC boilers. The tests, and the engineering evaluations, have evaluated the impact of co-firing at levels below 20% wood waste with eastern or western coal. In some tests, wood waste was trifired with coal and tyre-derived fuel (TDF). The results of both the tests
Joint Jochem, M. er al. FACT, 1996, 21, (Proceedings of the International Power Generation Conference, Volume 1: Environmental Control/Fuels and Combustion Technologies, 1996), 119-149. This paper describes the 1995 SM-IV staged mixing burner, which represents the most recent development stage of the Steinmuller staged mixing burner series started in 1978. Its main feature is the extreme deep staging ratio of -40% combustion air in the primary combustion zone, which results in NO, emissions as low as 350 to 550 mg/Nms depending on the fired fuel properties without additional measures like SOFA or FGR. In combination with a primary throat, a special coal nozzle was used to stabilize flame ignition close to the burner outlet to achieve deep staging.
Fuel and Energy Abstracts
September 1998 371
Boiler tuning using SPO at Detroit Edison’s River 98103961 Rouge Plant for best economic performance while minimizing NO. emissions
Haman, R. L. et al. FACT, 1996, 21, (Proceedings of the International Joint Power Generation Conference, Volume 1: Environmental Control/ Fuels and Combustion Technologies, 1996) l-8. In order to comply with the Clean Air Act Amendments of 1990 (CAAA), as well as to preparation for a more competitive business environment, a growing number of utilities arc including boiler tuning in strategies. Combustion tuning (optimization) is a logical first step in meeting both these challenges. Provided by Ultramax Corporation and EPRI, a technology based on sequential process optimization (SPO), is being used as a cost-effective tool to gain improvements prior to decisions for capitalintensive solutions. Called the ULTRAMAX” Method, this empirical method of optimization is capable of determining the best boiler capabilities and help delay, or even avoid, expensive retrofits or repowering. SPO can serve as a least-cost way to attain the right degree of compliance with current and future phases of CAAA. Tuning ensures a staged strategy to stay ahead of emissions regulations, but not so far ahead as to cause regret for taking actions that ultimately are not mandated or warranted. Detroit Edison is a large utility investigating SPO as a tool to lower NO, emissions and optimize boiler performance. The company has applied SPO to tune two coal-fired units at its River Rouge Power Plant to evaluate the technology for possible system-wide usage. Following the successful demonstration in reducing NO, from these units, SPO is being considered for use in other Detroit Edison fossil-fired plants. Tuning first will be used as a least-cost option to drive NO, to its lowest level with operating adjustment. In addition, optimization shows the true capability of the units and the margins available when the Phase II rules become effective in 2000. A case study of the second tuning process is given with a discussion of the opportunities offered by the technology.
Boiler with gravity circulating bed for co-generation 98103962 of coal gas and steam Zhang, X. and Cheng, Y. Faming Zhuanli Shenqing Gongkai Shuomingshu CN 1,144,260 (Cl. ClOJ3/80), 5 Mar 1997, Appt. 95108,875, 1 Sep 1995, 8 pp. (In Chinese) A fluidized bed in the lower portion of the boiler comprises three parallel beds: (1) a combustion bed; (2) a heat-transfer bed; and (3) a gasification bed, with submerged orifices arranged between them. By strengthening the gravity recirculation of fly ashes inside the furnace, the amount of ash recirculation increases, making effective use of the heat source and thus the gas output of the boiler improves with increasing temperature.
Characterization of coal with respect to carbon 98103963 burnout in pulverized coal-fired boilers Cloke, M. er al. Fuel, 1997, 76, (13) 1257-1267. Measured as percentage combustibles remaining, carbon burnout was determined for 16 world coals on a 1 MW pulverized coal combustion rig. The combustibles-remaining figures were correlated with parameters such as ash yield, carbon content, fuel ratio, rank, reactive macerals content and a reactivity parameter determined from a gray-scale histogram obtained by image analysis of the coals. The correlation of the reactivity parameter with the combustibles remaining was far superior to that given by any other parameter. Char samples collected at various points in the combustion rig confirmed that the intrinsic reactivity of char decreases during the combustion process and that the morphology of the char produced during the very early stages of combustion has a much greater effect than intrinsic reactivity on carbon burnout. !3:;3:;64
Co-firing switchgrass in a 50 MW pulverized coal
Regland, K. W. et al. Bioenergy ‘96, Proc. Natl. BioenergV Conf., 7th. 1996, 1, 113-120. Co-firing of switchgrass with pulverized coal took place in a 50 MW wallfired, radiant boiler generating station. Shredded switchgrass was fed to a hammermill onto a live bottom storage bunker. The switchgrass was moved onto a belt conveyor, via twin screw augers, which leads to a rotary air lack valve and through a pressurized pipe to the boiler where it is injected into the furnace at two points between first and second level coal burners. The project’s main objective was to evaluate the boiler performance, slagging behaviour and emissions of the co-fired switchgrass at replacement of rates of up to 20% by mass. Fuel handling and feeding, combustion behaviour, boiler response and emissions are favourable according to initial co-firing tests.
Cofiring wood waste in utility boilers: results of parametric testing and engineering evaluations
Steam raising (boiler operation/design)
and the engineering studies have included the influence of co-firing on boiler capacity, efficiency, and emissions such as NO, and SO?. The test results from the Allen Fossil Plant of Tennessee Valley Authority (TVA) and the Shawville Generating Station of GPUiPenelec are reviewed. The paper focuses upon the results of these tests in the context of co-firing test experience. Finally, the paper considers some of the parameters that emerge from co-firing engineering analyses and test programs and overviews some of the ongoing programmes in co-firing.
The combustion aerodynamics of a pulverized coal low NO, swirl burner in an industrial boiler
98lO3966
Sharifi, R. and Scaroni, A. W. FACT, 1996, 21, (Proceedings of the International Joint Power Generation Conference, Volume 1: Environmental Control/Fuels and Combustion Technologies, 1996), 59-66. The application of a Computational Fluid Dynamics (CFD) code (FLUENT) to predict temperature and velocity profiles and particle trajectories in an industrial boiler fired by a low NO, pulverized coal swirl burner is investigated. The code predictions were compared to experimental measurements of gas temperature, particle size distribution and particle velocities. A suction pyrometer and a Particle Counter Sizer Velocimeter Probe (PCSV-P) were employed as the diagnostics. Good agreement was found between the temperature predictions and the measurements. Using the Baum and Street model with a swelling factor of zero, the in situ particle size distributions were accurately predicted. The Type II flow issued from the burner could be transformed into Type III flow, by eliminating swirl from the primary air stream, which provided the preferred particle trajectories and increased the combustion efficiency, as illustrated by the numerical modelling.
98103967 Combustion characteristics pulverized-coal 300 MW. utility boiler
of a front-wall-fired
Costa, M. et al. Cornbust. Sci. Technol., 1997, 129, (l-6), 277-293. The results of an experimental study carried out in a 300 MW,, front-wallfired, pulverized-coal, utility boiler are described. The data reported include local mean gas species concentrations of Oz, CO, COs, NO, and gas temperatures measured at several ports in the boiler including those in the burner region and incident wall heat fluxes taken around the boiler periphery at 39 ports. The incident wall heat fluxes are reported for two boiler operating conditions. A considerable effort was made to assure minimum variations in boiler operating conditions and coal chemistry and particle size characteristics so that the data presented are especially useful for 3-D mathematical model evaluation and development. The findings were that: (i) the boundary air injected below the first row of burners leads to oxidizing conditions close to the back wall; (ii) local gas temperatures and CO concentrations in the boiler, near the burners, reached maximum values of about 1470°C and 1.6%, respectively; (iii) above the boiler nose the measured NO,, concentrations are reasonably uniform with averaged values of about 670 ppm; and (iv) wall radiant heat fluxes present maximum values at the side wall close to the intermediate row of burners.
99/03968 The demonstration of gas reburning technology on a 600 MWe boiler at Longannet, Scotland Macphail, J. M. and Rhine, J. M. Combust. Emiss. Control III, 1997, 340350. Edited by Adams, M., Institute of Energy, London, UK. The progress of the demonstration of gas reburning technology on a 600 MW, coal-fired boiler at Longannet in Scotland, owned and operated by Scottish Power is described. The project involves a partnership of leading European utilities and boiler manufacturers and will he the largest demonstration of the technology in the world. Details of the process design, the specification of the modifications to the boiler, and some of the aspects of the engineering design and installation are discussed. Plans for the testing and optimization of the system are outlined. The resultant plant data will be used to validate the design tools needed to exploit the technology post-demonstration.
9BlO3969 The design and installation of a gas reburn system on a 600 MW coal-fired boiler
Golland, E. S. et al. FACT, 1996, 21, (Proceedings of the International Joint Power Generation Conference, Volume 1: Environmental Control/ Fuels and Combustion Technologies, 1996) 101-109. In order to demonstrate the economic and technical viability of the technology, a gas reburn system with overfire air injection, to reduce NO, emissions was installed on a 600 MW coal-fired boiler. The facility was the Longannet Power Station, at Fife, Scotland. The design and retrofit of existing equipment were described.
Development of an ultra low NO, staged mixing burner for pulverized coal
98/03966
9aio3970
Tillman, D. A. FACT (Am. Sot. Mechanical Eng.), 1996,21, (Proceedings of the International Joint Power Generation Conference, Volume 1: Environmental Control/Fuels and Combustion Technologies, 1996). 455462. Under contract to the Electric Power Research Institute (EPRI), the Foster Wheeler Environmental Corporation has conducted parametric tests and engineering evaluations of co-firing wood waste with both eastern and western coal in cyclone and PC boilers. The tests, and the engineering evaluations, have evaluated the impact of co-firing at levels below 20% wood waste with eastern or western coal. In some tests, wood waste was trifired with coal and tyre-derived fuel (TDF). The results of both the tests
Joint Jochem, M. er al. FACT, 1996, 21, (Proceedings of the International Power Generation Conference, Volume 1: Environmental Control/Fuels and Combustion Technologies, 1996), 119-149. This paper describes the 1995 SM-IV staged mixing burner, which represents the most recent development stage of the Steinmuller staged mixing burner series started in 1978. Its main feature is the extreme deep staging ratio of -40% combustion air in the primary combustion zone, which results in NO, emissions as low as 350 to 550 mg/Nms depending on the fired fuel properties without additional measures like SOFA or FGR. In combination with a primary throat, a special coal nozzle was used to stabilize flame ignition close to the burner outlet to achieve deep staging.
Fuel and Energy Abstracts
September 1998 371