一种空气分级切向燃烧烟煤锅炉的燃尽特性
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摘要
采用实炉试验和数值模拟研究一台空气分级低NO_x切向燃烧烟煤锅炉飞灰燃尽度随主燃烧区过剩空气系数的变化特性。结果表明,该锅炉在临界过剩空气系数为0.88时,主燃烧区出口处易燃小颗粒刚好消耗烟气中所有氧气,小颗粒快速燃烧形成的高温烟气环境在缺氧量条件下对大颗粒燃烧未能起到促进作用,只增加主燃烧区辐射换热,降低SOFA风区烟气温度,而SOFA风区能提供富氧烟气环境。因此,在该临界过剩空气系数下,炉内温度场和氧量场协同性较差,不利于大颗粒的燃尽;降低主燃烧区过剩空气系数到临界值0.88以下,一部分小颗粒转移到SOFA风区,在富氧环境中小颗粒燃烧放热对烟温的提升促进大颗粒的燃尽,当主燃烧区过剩空气系数降低到0.71时,飞灰可燃物从1.89%下降到1.25%,在降低NO_x排放的同时,提高颗粒燃尽度。因此,对于空气分级低NO_x燃烧锅炉,运行时避开临界过剩空气系数对降低NO_x排放量和提高飞灰燃尽度有较为重要的意义。
The aim of this work was to investigate the burnout characteristics of bituminous coal in tangentially fired furnace with air staging. Both field tests and model simulation have been performed to characterize the impact of the primary zone stoichiometric ratio on the unburned carbon in fly ash, the main conclusions of this study are as follows, there exists a critical value of primary zone stoichiometric ratio of 0.88 in which all the oxygen in the flue gas is consumed by combustible small particles just at the outlet of the primary zone in this boiler, in this instance, the high temperature environment formed by rapid combustion of small particles can not promote the combustion of large particles with absence of oxygen, only increase the radiation heat transfer in the primary zone, and reduce the temperature of flue gas in the SOFA zone with a rich oxygen environment, and therefore, in the critical primary zone stoichiometric ratio in this boiler, the synergy between temperature field and oxygen field in furnace is poor,having a deleterious effect on burnout of large particles. Below aforementioned critical value of the primary zone stoichiometric ratio, some small flammable particles migrate the SOFA zone with enriched oxygen, the combustion of which increase flue gas temperature and promote the burning of large particles, when the primary zone stoichiometric ratio is reduced to 0.71, the combustibles in fly ash decrease from 1.89% to 1.25%, both particles burnout and NO_x reduction are improved.It is highly relevant in combustion tuning due to achievements of environmental effectiveness and burnout improvements at the same time.
The aim of this work was to investigate the burnout characteristics of bituminous coal in tangentially fired furnace with air staging. Both field tests and model simulation have been performed to characterize the impact of the primary zone stoichiometric ratio on the unburned carbon in fly ash, the main conclusions of this study are as follows, there exists a critical value of primary zone stoichiometric ratio of 0.88 in which all the oxygen in the flue gas is consumed by combustible small particles just at the outlet of the primary zone in this boiler, in this instance, the high temperature environment formed by rapid combustion of small particles can not promote the combustion of large particles with absence of oxygen, only increase the radiation heat transfer in the primary zone, and reduce the temperature of flue gas in the SOFA zone with a rich oxygen environment, and therefore, in the critical primary zone stoichiometric ratio in this boiler, the synergy between temperature field and oxygen field in furnace is poor,having a deleterious effect on burnout of large particles. Below aforementioned critical value of the primary zone stoichiometric ratio, some small flammable particles migrate the SOFA zone with enriched oxygen, the combustion of which increase flue gas temperature and promote the burning of large particles, when the primary zone stoichiometric ratio is reduced to 0.71, the combustibles in fly ash decrease from 1.89% to 1.25%, both particles burnout and NO_x reduction are improved.It is highly relevant in combustion tuning due to achievements of environmental effectiveness and burnout improvements at the same time.
引文
[1]Ribeirete A,Costa M.Impact of the air staging on the performance of a pulverized coal fired furnace[J].Proceedings of the Combustion Institute,2009,32(2):2667-2673.
[2]Cheoreon Moon,Yonmo Sung,Seongyong Eom,et al.NOx emissions and burnout characteristics of bituminous coal,lignite,and their blends in a pulverized coal-fired furnace[J].Experimental Thermal and Fluid Science,2015,62:99-108.
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[5]Ribeirete A,Costa M.Detailed measurements in a pulverized-coal-fired large-scale laboratory furnace with air staging[J].Fuel,2009,88(1):40-45.
[6]Pallarés J,Arauzo I,Díez L I.Numerical prediction of unburned carbon levels in large pulverized coal utility boilers[J].Fuel,2005,84(18):2365-2371.
[7]Gao H,Majeski A J,Runstedtler A.A method to target and correct sources of unburned carbon in coal-fired utility boilers[J].Fuel,2013,108:484-489.
[8]Stephenson P.Computer modelling of the combined effects of plant conditions and coal quality on burnout in utility furnaces[J].Fuel,2007,86(14):2026-2031.
[9]刘福国.石横发电厂#3锅炉再热汽温度调整试验报告[R].济南:山东电力研究院,2014.Liu Fuguo.Test report on reheating temperature adjustment of#3 boiler in Shi Heng power plant[R].Ji’nan:Shandong Electric Power Research Institute,2014(in Chinese).
[10]中华人民共和国国家质量监督检验检疫总局,中国国家标准化管理委员会.GB/T10184-88电站锅炉性能试验规程[S].北京:中国标准出版社,2016.People's Republic of China State Administration of Quality Supervision,Inspection and Quarantine,China National Standardization Management Committee.GB/T10184-88 Performance test code for utility boiler[S].Beijing:Standards Press of China,2016(in Chinese).
[11]刘福国,刘科,崔福兴,等.锅炉二次风挡板特性试验数据处理方法与应用[J].热能动力工程,2016,31(10):115-121.Liu Fuguo,Liu Ke,Cui Fuxing,et al.Data processing of air damper performance characteristics in boiler cold test and its application[J].Journal of Engineering for Thermal Energy&Power,2016,31(10):115-121(in Chinese).
[12]刘福国,崔福兴,刘科,等.切向燃烧摆动喷口附加进风诊断模型[J].动力工程学报,2017,37(8):606-614.Liu Fuguo,Cui Fuxing,Liu Ke,et al.Diagnosis model of additional air flow through gaps of tangential firing oscillating nozzles[J].Journal of Chinese Society of Power Engineering,2017,37(8):606-614(in Chinese).
[13]山东电力研究院,国家电网公司.锅炉二次风挡板特性实验数据的处理方法:中国,ZL 2015 1 0493413.2[P].2017.Shandong Electric Power Research Institute,State Grid.Data processing of air damper performance characteristics in boiler cold test:China,ZL 2015 10493413.2[P].2017(in Chinese).
[14]Pallarés J,Arauzo I,Díez L I.Numerical prediction of unburned carbon levels in large pulverized coal utility boilers[J].Fuel,2005,84(18):2364-2371.
[15]Kouprianov V I.Modeling of thermal characteristics for a furnace of a 500MW boiler fired with high-ash coal[J].Energy,2001,26(9):839-853.
[16]北京锅炉厂设计科.锅炉机组热力计算标准方法[M].北京:机械工业出版社,1976.Beijing Boiler Work,Ltd.Thermal calculation criterion for station boil units[M].Beijing:Mechanical Industry Press,1976(in Chinese).
[17]Biagini E,Tognotti L.A generalized correlation for coal devolatilization kinetics at high temperature[J].Fuel Processing Technology,2014,126:513-520.
[18]冯俊凯,沈幼庭.锅炉原理及计算[M].3版.北京:科学出版社,2003.Feng Junkai,Shen Youting.Theory and calculation of station boiler[M].3rd ed.Beijing:Science Press,2003(in Chinese).
[19]菲尔德M A,吉尔D W,摩根B B,等.煤粉燃烧[M].张明川,译.北京:水利电力出版社,1989.Field M A,Gill D W,Morgan B B,et al.Combustion of pulverised coal[M].Zhang Mingchuan,trans.Beijing:Water Conservancy&Hydropower Press,1989(in Chinese).
[20]Williams A,Backreedy R,Habib R,et al.Modelling of coal combustion:the current position[J].Fuel,2002,81(5):605-618.
[21]Fu W B,Zhang B L,Zheng S M.A Relationship Between the Kinetic Parameters of Char Combustion and the Coal's Properties[J].Combustionand Flame,1997,109(4):587-598.
[22]容銮恩,袁镇福,刘志敏,等.电站锅炉原理[M].北京:中国电力出版社,1997.Rong Luanen,Yuan Zhenfu,Liu Zhimin,et al.The principle of power plant boiler[M].Beijing:China Electric Power Press,1997(in Chinese).
[2]Cheoreon Moon,Yonmo Sung,Seongyong Eom,et al.NOx emissions and burnout characteristics of bituminous coal,lignite,and their blends in a pulverized coal-fired furnace[J].Experimental Thermal and Fluid Science,2015,62:99-108.
[3]Pallarés J,Arauzo I,Williams A.Integration of CFDcodes and advanced combustion models for quantitative burnout determination[J].Fuel,2007,86(15):2283-2290.
[4]Li Shi,Fu Zhongguang,Duan Xuenong,et al.Influence of combustion system retrofit on NOx formation characteristics in a 300MW tangentially fired furnace[J].Applied Thermal Engineering,2016,98:766-777.
[5]Ribeirete A,Costa M.Detailed measurements in a pulverized-coal-fired large-scale laboratory furnace with air staging[J].Fuel,2009,88(1):40-45.
[6]Pallarés J,Arauzo I,Díez L I.Numerical prediction of unburned carbon levels in large pulverized coal utility boilers[J].Fuel,2005,84(18):2365-2371.
[7]Gao H,Majeski A J,Runstedtler A.A method to target and correct sources of unburned carbon in coal-fired utility boilers[J].Fuel,2013,108:484-489.
[8]Stephenson P.Computer modelling of the combined effects of plant conditions and coal quality on burnout in utility furnaces[J].Fuel,2007,86(14):2026-2031.
[9]刘福国.石横发电厂#3锅炉再热汽温度调整试验报告[R].济南:山东电力研究院,2014.Liu Fuguo.Test report on reheating temperature adjustment of#3 boiler in Shi Heng power plant[R].Ji’nan:Shandong Electric Power Research Institute,2014(in Chinese).
[10]中华人民共和国国家质量监督检验检疫总局,中国国家标准化管理委员会.GB/T10184-88电站锅炉性能试验规程[S].北京:中国标准出版社,2016.People's Republic of China State Administration of Quality Supervision,Inspection and Quarantine,China National Standardization Management Committee.GB/T10184-88 Performance test code for utility boiler[S].Beijing:Standards Press of China,2016(in Chinese).
[11]刘福国,刘科,崔福兴,等.锅炉二次风挡板特性试验数据处理方法与应用[J].热能动力工程,2016,31(10):115-121.Liu Fuguo,Liu Ke,Cui Fuxing,et al.Data processing of air damper performance characteristics in boiler cold test and its application[J].Journal of Engineering for Thermal Energy&Power,2016,31(10):115-121(in Chinese).
[12]刘福国,崔福兴,刘科,等.切向燃烧摆动喷口附加进风诊断模型[J].动力工程学报,2017,37(8):606-614.Liu Fuguo,Cui Fuxing,Liu Ke,et al.Diagnosis model of additional air flow through gaps of tangential firing oscillating nozzles[J].Journal of Chinese Society of Power Engineering,2017,37(8):606-614(in Chinese).
[13]山东电力研究院,国家电网公司.锅炉二次风挡板特性实验数据的处理方法:中国,ZL 2015 1 0493413.2[P].2017.Shandong Electric Power Research Institute,State Grid.Data processing of air damper performance characteristics in boiler cold test:China,ZL 2015 10493413.2[P].2017(in Chinese).
[14]Pallarés J,Arauzo I,Díez L I.Numerical prediction of unburned carbon levels in large pulverized coal utility boilers[J].Fuel,2005,84(18):2364-2371.
[15]Kouprianov V I.Modeling of thermal characteristics for a furnace of a 500MW boiler fired with high-ash coal[J].Energy,2001,26(9):839-853.
[16]北京锅炉厂设计科.锅炉机组热力计算标准方法[M].北京:机械工业出版社,1976.Beijing Boiler Work,Ltd.Thermal calculation criterion for station boil units[M].Beijing:Mechanical Industry Press,1976(in Chinese).
[17]Biagini E,Tognotti L.A generalized correlation for coal devolatilization kinetics at high temperature[J].Fuel Processing Technology,2014,126:513-520.
[18]冯俊凯,沈幼庭.锅炉原理及计算[M].3版.北京:科学出版社,2003.Feng Junkai,Shen Youting.Theory and calculation of station boiler[M].3rd ed.Beijing:Science Press,2003(in Chinese).
[19]菲尔德M A,吉尔D W,摩根B B,等.煤粉燃烧[M].张明川,译.北京:水利电力出版社,1989.Field M A,Gill D W,Morgan B B,et al.Combustion of pulverised coal[M].Zhang Mingchuan,trans.Beijing:Water Conservancy&Hydropower Press,1989(in Chinese).
[20]Williams A,Backreedy R,Habib R,et al.Modelling of coal combustion:the current position[J].Fuel,2002,81(5):605-618.
[21]Fu W B,Zhang B L,Zheng S M.A Relationship Between the Kinetic Parameters of Char Combustion and the Coal's Properties[J].Combustionand Flame,1997,109(4):587-598.
[22]容銮恩,袁镇福,刘志敏,等.电站锅炉原理[M].北京:中国电力出版社,1997.Rong Luanen,Yuan Zhenfu,Liu Zhimin,et al.The principle of power plant boiler[M].Beijing:China Electric Power Press,1997(in Chinese).