利用电站锅炉耦合秸秆直燃炉提高再热汽温和SCR烟温经济性分析
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摘要
针对电站锅炉普遍存在的再热蒸汽温度偏低和选择性催化还原(SCR)烟气脱硝系统低负荷下无法正常投运的问题,提出通过一种电站锅炉耦合秸秆绝热直燃炉,利用秸秆直燃的高温烟气显热直接提高锅炉尾部烟道烟气温度的技术方案。以某超临界350 MW机组锅炉为例,对不同负荷下将耦合秸秆绝热直燃炉高温烟气分别引入低温再热器进口烟道和SCR烟气脱硝系统前烟道的情况进行热力计算和经济性分析。结果表明:将1 000℃高温烟气引入低温再热器进口烟道时,100%负荷工况下,消耗秸秆3 749 kg/h,可将再热蒸汽温度升高13.5℃,节省供电标准煤耗1.86 g/(kW·h);50%负荷工况下,消耗秸秆3 749 kg/h,再热蒸汽温度升高33.3℃,节省供电标准煤耗7.39g/(kW·h);将1000℃高温烟气引入SCR烟气脱硝系统前烟道时,50%负荷工况下,消耗秸秆580 kg/h,SCR烟气脱硝系统入口烟温升高8.7℃,满足SCR烟气脱硝系统投运要求,供电标准煤耗增加0.84 g/(kW·h)。
In view of the common problems occur in utility boilers, such as low reheat steam temperature and failure operation of SCR flue gas denitration system at low load, a technical program of utility boiler coupling straw adiabatic direct combustion furnace was proposed. In this program, the flue gas temperature of boiler tail flue is directly increased by using the sensible heat of high temperature flue gas produced by straw combustion.Taking an ultra supercritical 350 MW unit boiler as the example, thermodynamic calculation and economic analysis were performed when the high temperature flue gas produced by straw combustion in adiabatic direct firing boiler was introduced to the inlet flue duct of the low temperature reheater and the flue duct in front of the SCR denitration system at different loads. The results show that, when the 1 000 ℃ high temperature flue gas was sent to the inlet flue duct of low temperature reheater at 100% load, the consumption of straw was 3 749 kg/h, the reheat steam temperature increased by 13.5℃ and the power supply coal consumption reduced by 1.86 g/(kW·h).At 50% load, the consumption of straw was 3 749 kg/h, the reheat steam temperature increased by 33.3℃ and the power supply coal consumption reduced by 7.39 g/(k W·h). When the 1 000 ℃ high temperature flue gas was sent to the flue duct in front of the SCR flue gas denitration system at 50% load, the consumption of straw was580 kg/h, the flue gas temperature at the SCR denitration system inlet increased by 8.7℃ and the power supply coal consumption increased by 0.84 g/(kW·h), which met the requirements of the SCR denitration system.
In view of the common problems occur in utility boilers, such as low reheat steam temperature and failure operation of SCR flue gas denitration system at low load, a technical program of utility boiler coupling straw adiabatic direct combustion furnace was proposed. In this program, the flue gas temperature of boiler tail flue is directly increased by using the sensible heat of high temperature flue gas produced by straw combustion.Taking an ultra supercritical 350 MW unit boiler as the example, thermodynamic calculation and economic analysis were performed when the high temperature flue gas produced by straw combustion in adiabatic direct firing boiler was introduced to the inlet flue duct of the low temperature reheater and the flue duct in front of the SCR denitration system at different loads. The results show that, when the 1 000 ℃ high temperature flue gas was sent to the inlet flue duct of low temperature reheater at 100% load, the consumption of straw was 3 749 kg/h, the reheat steam temperature increased by 13.5℃ and the power supply coal consumption reduced by 1.86 g/(kW·h).At 50% load, the consumption of straw was 3 749 kg/h, the reheat steam temperature increased by 33.3℃ and the power supply coal consumption reduced by 7.39 g/(k W·h). When the 1 000 ℃ high temperature flue gas was sent to the flue duct in front of the SCR flue gas denitration system at 50% load, the consumption of straw was580 kg/h, the flue gas temperature at the SCR denitration system inlet increased by 8.7℃ and the power supply coal consumption increased by 0.84 g/(kW·h), which met the requirements of the SCR denitration system.
引文
[1]章斐然,周克毅,徐奇,等.燃煤机组低负荷运行SCR烟气脱硝系统应对措施[J].热力发电,2016,45(7):78-83.ZHANG Feiran,ZHOU Keyi,XU Qi,et al.Countermeasures for SCR denitration system of coal-fired unit during low-load operation[J].Thermal Power Generation,2016,45(7):78-83.
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[6]黄文静,戴苏峰,艾春美,等.电站燃煤锅炉全负荷SCR脱硝控制技术探讨[J].节能技术,2015,33(2):189-192.HUANG Wenjing,DAI Sufeng,AI Chunmei,et al.Discussion about SCR denitration control technology under full load in a coal-fired boiler[J].Energy Conservation Technology,2015,33(2):189-192.
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[8]胡蓉.关于锅炉SCR全负荷适应性改造的探讨[J].中国科技信息,2015,3(1):179-181.HU Rong.Discussion about SCR full load adaptation of the boiler[J].China Science and Technology Information,2015,3(1):179-181.
[9]李励.基于弹性回热技术的低负荷SCR脱硝系统性能研究[J].电力与能源,2016,37(6):740-745.LI Li.Performance of a low-load SCR de-NOx system based on the flexible feed water regeneration technology[J].Power and Energy,2016,37(6):740-745.
[10]ZHANG S,LI H,ZHONG Q.Promotional effect of F-doped V2O5-WO3/TiO2 catalyst for NH3-SCR of NO at low-temperature[J].Applied Catalysis A:General,2012,435:156-162.
[11]DENG Y X,CHEN X,SHAO R,et al.V2O5-WO3/TiO2catalysts for low temperature NH3 SCR:catalytic activity and characterization[J].Key Engineering Materials,2016,697:275-278.
[12]SHEN M,LI C,WANG J,et al.New insight into the promotion effect of Cu doped V2O5-WO3/TiO2 for low temperature NH3-SCR performance[J].Rsc Advances,2015,5(44):35155-35165.
[13]李永生,阎维平,田舜尧,等.电站锅炉系统及电站锅炉整合生物质气化补燃提高尾部烟温的方法:107255269A[P].2017-10-17.LI Yongsheng,YAN Weiping,TIAN Shunyao,et al.The method of improving the flue gas temperature by the combined biomass gasification of utility boiler system and utility boiler:107255269A[P].2017-10-17.
[14]赵振宁,王晶晶,徐立伟,等.300 MW锅炉再热汽温低的原因分析及改造[J].中国电力,2012,45(12):21-25.ZHAO Zhenning,WANG Jingjing,XU Liwei,et al.Reasons and retrofits of low reheat steam temperature of300 MW boiler[J].Electric Power,2012,45(12):21-25.
[15]孙科,吴松,秦大川,等.提高再热汽温对锅炉和机组热力特性的影响及经济性分析[J].热力发电,2014,43(8):19-23.SUN Ke,WU Song,QIN Dachuan,et al.Effect of improving reheat steam temperature on boiler thermal performance and economic analysis[J].Thermal Power Generation,2014,43(8):19-23.
[16]王春昌.蒸发吸热比例变化对700℃超超临界机组锅炉设计的影响[J].热力发电,2013,42(1):59-62.WANG Chunchang.Influence of evaporating and heat absorption proportion on design of 700℃ultrasupercritical boilers[J].Thermal Power Generation,2013,42(1):59-62.
[17]TARELIN A A.Influence of the reheat temperature on the efficiency of the wet-steam turbines of thermal power plants that operate under variable conditions[J].Thermal Engineering,2017,64(4):295-300.
[18]WEITZEL P S.Steam generator for advanced ultra supercritical power plants 700℃to 760℃[C]//ASME2011 Power Conference Collocated with Jsme Icope.2011:281-291.
[19]韩英昆,孟祥荣,牟琳,等.超临界火电机组再热汽温控制系统分析[J].山东电力技术,2010(1):66-70.HAN Yingkun,MENG Xiangrong,MOU Lin,et al.Analysis on RH control system on supercritical power generation unit[J].Shandong Electric Power,2010(1):66-70.
[20]WANG J,ZHAO Z,XU L,et al.Scheme analysis of capacity-increasing transformation for reheaters of300 MW boilers in a power plant[C]//International Conference on Materials for Renewable Energy and Environment.IEEE,2013:698-702.
[21]马隆龙,吴创之,孙立.生物质气化技术及其应用[M].北京:化学工业出版社,2003:182-183.MA Longlong,WU Chuangzhi,SUN Li.Biomass gasification technology and its application[M].Beijing:Chemical Industry Press,2003:182-183.
[22]GANESH A,BANERJEE R.Biomass pyrolysis for power generation:a potential technology[J].Renewable Energy,2001,22(1/2/3):9-14.
[23]孙俊威,阎维平,赵文娟,等.600 MW超临界燃煤锅炉生物质气体再燃的数值研究[J].动力工程学报,2012,32(2):89-95.SUN Junwei,YAN Weiping,ZHAO Wenjuan,et al.Numerical study on biomass gas reburning in a 600 MWsupercritical coal-fired boiler[J].Journal of Chinese Society of Power Engineering,2012,32(2):89-95.
[24]HIGGINS B,YAN L,GADALLA H,et al.Biomass co-firing retrofit with ROFA for NOx reduction[J].Polish Journal of Environmental Studies,2010,19(6):1185-1197.
[25]HARDING N S,ADAMS B R.Biomass as a reburning fuel:a specialized cofiring application[J].Biomass&Bioenergy,2000,19(6):429-445.
[26]费茂华.一台35 t/h燃煤粉过热器锅炉的设计[J].锅炉制造,2015(4):8-10.FEI Maohua.The design of 35 t/h pulverized coal fired superheater boiler[J].Boiler Manufacturing,2015(4):8-10.
[2]沈伯雄,赵宁,刘亭.烟气脱硝选择性催化还原催化剂反应模拟研究[J].中国电机工程学报,2011,31(8):31-37.SHEN Boxiong,ZHAO Ning,LIU Ting.Mathematical simulation of flue gas denitration based on selective catalytic reduction catalyst[J].Proceedings of the CSEE,2011,31(8):31-37.
[3]鲁芬,问树荣,冯润富,等.某600 MW机组锅炉换热面分级及烟气流场优化[J].热力发电,2018,47(5):124-130.LU Fen,WEN Shurong,FENG Runfu,et al.Classification of heat exchanger and optimization of flue gas flow field in a 600 MW coal-fired boiler[J].Thermal Power Generation,2018,47(5):124-130.
[4]王乐乐,何川,王凯,等.SCR脱硝催化剂低负荷运行评估技术研究与应用[J].热力发电,2018,47(10):24-30.WANG Lele,HE Chuan,WANG Kai,et al.Research and application of low-load operation evaluation technology for SCR catalysts[J].Thermal Power Generation,2018,47(10):24-30.
[5]白文刚,于在松,张一帆,等.超超临界二次再热机组锅炉全负荷脱硝特性[J].热力发电,2017,46(8):141-144.BAI Wengang,YU Zaisong,ZHANG Yifan,et al.Denitration performance of an ultra-supercritical unit boiler with double-reheat cycle under full load conditons[J].Thermal Power Generation,2017,46(8):141-144.
[6]黄文静,戴苏峰,艾春美,等.电站燃煤锅炉全负荷SCR脱硝控制技术探讨[J].节能技术,2015,33(2):189-192.HUANG Wenjing,DAI Sufeng,AI Chunmei,et al.Discussion about SCR denitration control technology under full load in a coal-fired boiler[J].Energy Conservation Technology,2015,33(2):189-192.
[7]LEHTORANTA K,VESALA H,KOPONEN P,et al.Selective catalytic reduction operation with heavy fuel oil:NOx,NH3,and particle emissions[J].Environmental Science&Technology,2015,49(7):4735-41.
[8]胡蓉.关于锅炉SCR全负荷适应性改造的探讨[J].中国科技信息,2015,3(1):179-181.HU Rong.Discussion about SCR full load adaptation of the boiler[J].China Science and Technology Information,2015,3(1):179-181.
[9]李励.基于弹性回热技术的低负荷SCR脱硝系统性能研究[J].电力与能源,2016,37(6):740-745.LI Li.Performance of a low-load SCR de-NOx system based on the flexible feed water regeneration technology[J].Power and Energy,2016,37(6):740-745.
[10]ZHANG S,LI H,ZHONG Q.Promotional effect of F-doped V2O5-WO3/TiO2 catalyst for NH3-SCR of NO at low-temperature[J].Applied Catalysis A:General,2012,435:156-162.
[11]DENG Y X,CHEN X,SHAO R,et al.V2O5-WO3/TiO2catalysts for low temperature NH3 SCR:catalytic activity and characterization[J].Key Engineering Materials,2016,697:275-278.
[12]SHEN M,LI C,WANG J,et al.New insight into the promotion effect of Cu doped V2O5-WO3/TiO2 for low temperature NH3-SCR performance[J].Rsc Advances,2015,5(44):35155-35165.
[13]李永生,阎维平,田舜尧,等.电站锅炉系统及电站锅炉整合生物质气化补燃提高尾部烟温的方法:107255269A[P].2017-10-17.LI Yongsheng,YAN Weiping,TIAN Shunyao,et al.The method of improving the flue gas temperature by the combined biomass gasification of utility boiler system and utility boiler:107255269A[P].2017-10-17.
[14]赵振宁,王晶晶,徐立伟,等.300 MW锅炉再热汽温低的原因分析及改造[J].中国电力,2012,45(12):21-25.ZHAO Zhenning,WANG Jingjing,XU Liwei,et al.Reasons and retrofits of low reheat steam temperature of300 MW boiler[J].Electric Power,2012,45(12):21-25.
[15]孙科,吴松,秦大川,等.提高再热汽温对锅炉和机组热力特性的影响及经济性分析[J].热力发电,2014,43(8):19-23.SUN Ke,WU Song,QIN Dachuan,et al.Effect of improving reheat steam temperature on boiler thermal performance and economic analysis[J].Thermal Power Generation,2014,43(8):19-23.
[16]王春昌.蒸发吸热比例变化对700℃超超临界机组锅炉设计的影响[J].热力发电,2013,42(1):59-62.WANG Chunchang.Influence of evaporating and heat absorption proportion on design of 700℃ultrasupercritical boilers[J].Thermal Power Generation,2013,42(1):59-62.
[17]TARELIN A A.Influence of the reheat temperature on the efficiency of the wet-steam turbines of thermal power plants that operate under variable conditions[J].Thermal Engineering,2017,64(4):295-300.
[18]WEITZEL P S.Steam generator for advanced ultra supercritical power plants 700℃to 760℃[C]//ASME2011 Power Conference Collocated with Jsme Icope.2011:281-291.
[19]韩英昆,孟祥荣,牟琳,等.超临界火电机组再热汽温控制系统分析[J].山东电力技术,2010(1):66-70.HAN Yingkun,MENG Xiangrong,MOU Lin,et al.Analysis on RH control system on supercritical power generation unit[J].Shandong Electric Power,2010(1):66-70.
[20]WANG J,ZHAO Z,XU L,et al.Scheme analysis of capacity-increasing transformation for reheaters of300 MW boilers in a power plant[C]//International Conference on Materials for Renewable Energy and Environment.IEEE,2013:698-702.
[21]马隆龙,吴创之,孙立.生物质气化技术及其应用[M].北京:化学工业出版社,2003:182-183.MA Longlong,WU Chuangzhi,SUN Li.Biomass gasification technology and its application[M].Beijing:Chemical Industry Press,2003:182-183.
[22]GANESH A,BANERJEE R.Biomass pyrolysis for power generation:a potential technology[J].Renewable Energy,2001,22(1/2/3):9-14.
[23]孙俊威,阎维平,赵文娟,等.600 MW超临界燃煤锅炉生物质气体再燃的数值研究[J].动力工程学报,2012,32(2):89-95.SUN Junwei,YAN Weiping,ZHAO Wenjuan,et al.Numerical study on biomass gas reburning in a 600 MWsupercritical coal-fired boiler[J].Journal of Chinese Society of Power Engineering,2012,32(2):89-95.
[24]HIGGINS B,YAN L,GADALLA H,et al.Biomass co-firing retrofit with ROFA for NOx reduction[J].Polish Journal of Environmental Studies,2010,19(6):1185-1197.
[25]HARDING N S,ADAMS B R.Biomass as a reburning fuel:a specialized cofiring application[J].Biomass&Bioenergy,2000,19(6):429-445.
[26]费茂华.一台35 t/h燃煤粉过热器锅炉的设计[J].锅炉制造,2015(4):8-10.FEI Maohua.The design of 35 t/h pulverized coal fired superheater boiler[J].Boiler Manufacturing,2015(4):8-10.
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