燃煤烟气超低排放全流程协同削减三氧化硫效果分析
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摘要
烟气三氧化硫(SO_3)是形成雾霾的前驱体之一,研究火电厂烟气污染物控制流程中SO_3的形态、浓度、排放水平以及影响因素很有必要。对容量300~1 000 MW的燃煤机组超低排放设施进行实测,并对1 000 MW机组开展了全流程测试,同时与常规污染物控制流程进行比较,表明超低排放设施对SO_3具有更好的控制效果,SO_3综合脱除效率可达到90%。对烟气流程各设备脱除SO_3机理与减排效果进行分析,结果表明:(1)SCR脱硝装置具有将SO_2催化氧化成SO_3的作用。(2)空气预热器烟温降低过程间接消耗SO_3,低低温电除尘器、湿法脱硫吸收塔与湿式电除尘器对SO_3有削减作用,各设备对SO_3的削减份额分别占SO_3总量的30%、40%、15%、5%。(3)空气预热器、电除尘器运行温度对SO_3脱除率有较大影响。(4)高效脱硫协同除尘一体化吸收塔具有更好的脱除SO_3效果。
It is necessary to study the formation, concentration, emission level and influencing factors of the sulfur trioxide in the control process of flue gas pollutants in thermal power plants because the sulfur trioxide in the flue gas is one of the precursors of smog. Based on the onsite measurements of ultra-low emission facilities of 300~1 000 MW coal-fired units and the whole process test of a 1 000 MW unit, the comparison with the conventional pollutant control process shows that the ultra-low emission facilities have a better control effect on SO_3 with SO_3 comprehensive removal efficiency reaching 90%. The SO_3 removal mechanism and effect of each equipment in flue gas flow process were also analyzed. The results show that:(1) SCR denitrification device has a catalytic oxidation effect on SO_2 converted to SO_3.(2) The air preheater consumes SO_3 indirectly during the process of the flue gas temperature drop. The low-low temperature electrostatic precipitator, the wet desulfurization absorber and the wet electrostatic precipitator all contribute to the SO_3 reduction, accounting for 30%, 40%, 15% and 5% of total reduction respectively.(3) The air preheater, electrostatic precipitator operating temperature has great impacts on SO_3 removal rate.(4) The high-efficiency desulfurization synergistic dust removing integrated absorption tower has a better effect of SO_3 removal.
It is necessary to study the formation, concentration, emission level and influencing factors of the sulfur trioxide in the control process of flue gas pollutants in thermal power plants because the sulfur trioxide in the flue gas is one of the precursors of smog. Based on the onsite measurements of ultra-low emission facilities of 300~1 000 MW coal-fired units and the whole process test of a 1 000 MW unit, the comparison with the conventional pollutant control process shows that the ultra-low emission facilities have a better control effect on SO_3 with SO_3 comprehensive removal efficiency reaching 90%. The SO_3 removal mechanism and effect of each equipment in flue gas flow process were also analyzed. The results show that:(1) SCR denitrification device has a catalytic oxidation effect on SO_2 converted to SO_3.(2) The air preheater consumes SO_3 indirectly during the process of the flue gas temperature drop. The low-low temperature electrostatic precipitator, the wet desulfurization absorber and the wet electrostatic precipitator all contribute to the SO_3 reduction, accounting for 30%, 40%, 15% and 5% of total reduction respectively.(3) The air preheater, electrostatic precipitator operating temperature has great impacts on SO_3 removal rate.(4) The high-efficiency desulfurization synergistic dust removing integrated absorption tower has a better effect of SO_3 removal.
引文
[1]纪培栋.SCR催化剂SO2氧化机理及调控机制研究[D].杭州:浙江大学,2016.
[2]朱崇兵,金保升,李峰,等.SO2氧化对SCR法烟气脱硝的影响[J].锅炉技术,2008,39(3):68–72.ZHU Chongbing,JIN Baosheng,LI Feng,et al.Effect of SO2oxidation on SCR-De NOx[J].Boiler Technology,2008,39(3):68–72.
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[6]FLEIG D,ANDERSSON K,NORMANN F,et al.SO3 formation under oxyfuel combustion conditions[J].Industrial&Engineering Chemistry Research,2011,50(14):8505–8514.
[7]OFFEN G.Modeling of SO3 formation process in coal-fired boilers[R].Palo Alto:EPRI,2007.
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[10]DUNN J P,KOPPULA P R,STENGER H G,et al.Oxidation of sulfur dioxide to sulfur trioxide over supported vanadia catalysts[J].Applied Catalysis B:Environmental,1998,19(2):103–117.
[11]李峰.以纳米Ti O2为载体的燃煤烟气脱硝SCR催化剂的研究[D].南京:东南大学,2006.
[12]J BURKE J M,JOHNSON K L.Ammonium sulfate and bisulfate formation in air preheaters[R].US EPA 600/7-82-025a,1982.
[13]马双忱,金鑫,孙云雪,等.SCR烟气脱硝过程硫酸氢铵的生成机理与控制[J].热力发电,2010,39(8):12–17.MA Shuangchen,JIN Xin,SUN Yunxue,et al.The formation mechanism of ammonium bisulfate in SCR flue gas denitrification process and control thereof[J].Thermal Power Generation,2010,39(8):12–17.
[14]Chetan Chothani,Robert Morey.ABS measurement for SCR NOx control and air heater protection[C]//2008 DOE-EPRI-EPA-A&WMA Power Plant Air Pollutant Control"Mega"Symposium,2008,Baltimore.
[15]姚宣,郑鹏,郑伟.SCR脱硝系统最低连续喷氨温度的研究[J].中国电力,2016,49(1):146–150.YAO Xuan,ZHENG Peng,ZHENG Wei.Study on minimum continuous-operation temperature of SCR system[J].Electric Power,2016,49(1):146–150.
[16]沈艳梅,董琨,崔智勇,等.低低温电除尘器设计烟温的理论计算及存在问题[J].中国电力,2016,49(7):151–156.SHEN Yanmei,DONG Kun,CUI Zhiyong,et al.The theoretical calculation of designed temperature of flue gas in low-low temperature electrostatic precipitator and the existing problems[J].Electric Power,2016,49(7):151–156.
[17]NAKAYAMA Y,NAKAMURA S,TAKEUCHI Y,et al.MHI high efficiency system-proven technology for multi pollutant removal[R].Hiroshima Research&Development Center.2011:1-11.
[18]陈瑶姬,孟炜,胡达清.燃煤电厂烟气超低排放技术对三氧化硫脱除影响的研究[J].上海节能,2015(12):657–660.CHEN Yaoji,MENG Wei,HU Daqing.Research on coal-fired power plant flue gas ultra low emission technology influence on sulfur trioxide removal[J].Shanghai Energy Conservation,2015(12):657–660.
[19]张绪辉.低低温电除尘器对细颗粒物及三氧化硫的协同脱除研究[D].北京:清华大学,2015.
[20]滕农,张运宇,魏晗等.石灰石/石膏湿法FGD装置除尘效率和SO3脱除率探讨[J].电力环境保护,2008,24(4):27–28.TENG Nong,ZHANG Yunyu,WEI Han,et al.Discussion on ash removal efficiency and sulfur trioxide removal efficiency of WFGD system[J].Electric Power Environmental Protection,2008,24(4):27–28.
[21]刘宇,单广波,闫松,等.燃煤锅炉烟气中SO3的生成、危害及控制技术研究进展[J].环境工程,2016,34(12):93–97.LIU Yu,SHAN Guangbo,YAN Song,et al.Progress in research on formation,harm and control technique of SO3 in flue gas of coal-fired boiler[J].Environmental Engineering,2016,34(12):93–97.
[2]朱崇兵,金保升,李峰,等.SO2氧化对SCR法烟气脱硝的影响[J].锅炉技术,2008,39(3):68–72.ZHU Chongbing,JIN Baosheng,LI Feng,et al.Effect of SO2oxidation on SCR-De NOx[J].Boiler Technology,2008,39(3):68–72.
[3]MOSER R E.SO3's impacts on plant O&M:Part I[J].Power,2006,150(8):40–42.
[4]新井纪男.燃烧生成物的发生与抑制技术[M].赵黛青,赵哲石,王昶,等译.北京:科学出版社:2001.138-141.
[5]魏宏鸽,程雪山,马彦斌,等.燃煤烟气中SO3的产生与转化及其抑制对策探讨[J].发电与空调,2012,33(2):1–4.WEI Hongge,CHENG Xueshan,MA Yanbin,et al.Some discussion about SO3's generation,transformation and its inhibiting methods in coal-fired flue gas[J].Refrigeration Air Conditioning&Electric Power Machinery,2012,33(2):1–4.
[6]FLEIG D,ANDERSSON K,NORMANN F,et al.SO3 formation under oxyfuel combustion conditions[J].Industrial&Engineering Chemistry Research,2011,50(14):8505–8514.
[7]OFFEN G.Modeling of SO3 formation process in coal-fired boilers[R].Palo Alto:EPRI,2007.
[8]GREENWOOD N N,EARNSHAW A.Chemistry of the Elements[M].2nd ed.Butterworth-Heinemann,Oxford,U K,1997:321-332.
[9]马双忱,邓悦,吴文龙,等.SCR脱硝过程中硫酸氢铵形成特性实验研究[J].动力工程学报,2016,36(2):143–150.MA Shuangchen,DENG Yue,WU Wenlong,et al.Experimental research on ABS formation characteristics in SCR denitrification process[J].Journal Of Chinese Society Of Power Engineering,2016,36(2):143–150.
[10]DUNN J P,KOPPULA P R,STENGER H G,et al.Oxidation of sulfur dioxide to sulfur trioxide over supported vanadia catalysts[J].Applied Catalysis B:Environmental,1998,19(2):103–117.
[11]李峰.以纳米Ti O2为载体的燃煤烟气脱硝SCR催化剂的研究[D].南京:东南大学,2006.
[12]J BURKE J M,JOHNSON K L.Ammonium sulfate and bisulfate formation in air preheaters[R].US EPA 600/7-82-025a,1982.
[13]马双忱,金鑫,孙云雪,等.SCR烟气脱硝过程硫酸氢铵的生成机理与控制[J].热力发电,2010,39(8):12–17.MA Shuangchen,JIN Xin,SUN Yunxue,et al.The formation mechanism of ammonium bisulfate in SCR flue gas denitrification process and control thereof[J].Thermal Power Generation,2010,39(8):12–17.
[14]Chetan Chothani,Robert Morey.ABS measurement for SCR NOx control and air heater protection[C]//2008 DOE-EPRI-EPA-A&WMA Power Plant Air Pollutant Control"Mega"Symposium,2008,Baltimore.
[15]姚宣,郑鹏,郑伟.SCR脱硝系统最低连续喷氨温度的研究[J].中国电力,2016,49(1):146–150.YAO Xuan,ZHENG Peng,ZHENG Wei.Study on minimum continuous-operation temperature of SCR system[J].Electric Power,2016,49(1):146–150.
[16]沈艳梅,董琨,崔智勇,等.低低温电除尘器设计烟温的理论计算及存在问题[J].中国电力,2016,49(7):151–156.SHEN Yanmei,DONG Kun,CUI Zhiyong,et al.The theoretical calculation of designed temperature of flue gas in low-low temperature electrostatic precipitator and the existing problems[J].Electric Power,2016,49(7):151–156.
[17]NAKAYAMA Y,NAKAMURA S,TAKEUCHI Y,et al.MHI high efficiency system-proven technology for multi pollutant removal[R].Hiroshima Research&Development Center.2011:1-11.
[18]陈瑶姬,孟炜,胡达清.燃煤电厂烟气超低排放技术对三氧化硫脱除影响的研究[J].上海节能,2015(12):657–660.CHEN Yaoji,MENG Wei,HU Daqing.Research on coal-fired power plant flue gas ultra low emission technology influence on sulfur trioxide removal[J].Shanghai Energy Conservation,2015(12):657–660.
[19]张绪辉.低低温电除尘器对细颗粒物及三氧化硫的协同脱除研究[D].北京:清华大学,2015.
[20]滕农,张运宇,魏晗等.石灰石/石膏湿法FGD装置除尘效率和SO3脱除率探讨[J].电力环境保护,2008,24(4):27–28.TENG Nong,ZHANG Yunyu,WEI Han,et al.Discussion on ash removal efficiency and sulfur trioxide removal efficiency of WFGD system[J].Electric Power Environmental Protection,2008,24(4):27–28.
[21]刘宇,单广波,闫松,等.燃煤锅炉烟气中SO3的生成、危害及控制技术研究进展[J].环境工程,2016,34(12):93–97.LIU Yu,SHAN Guangbo,YAN Song,et al.Progress in research on formation,harm and control technique of SO3 in flue gas of coal-fired boiler[J].Environmental Engineering,2016,34(12):93–97.