SCR脱硝系统性能及空气预热器阻力上升分析
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摘要
NO_x排放浓度、氨逃逸浓度难以控制及空气预热器阻力上升,是SCR脱硝系统超低排放改造中遇到的主要问题。以某SCR脱硝系统超低排放改造后的300 MW机组为研究对象,通过测试得知:(1)SCR反应器出口NO_x分布不均,氨逃逸浓度超标严重,氨逃逸监测表计示值不具代表性,造成NO_x排放浓度控制困难和空气预热器阻力上升;(2)过度追求NO_x超低排放浓度,造成催化剂活性、主要化学成分明显衰减,硫酸氢铵在其表面沉积严重。对此提出的改进措施为:进行NO_x浓度烟气在线监测系统(CEMS)多点取样改造,定期进行喷氨优化和催化剂性能检测,以改善SCR系统运行效果和提高运行的经济性。
Some major problems were encountered such as the difficulties to control NOx emission concentration and ammonia escape concentration as well as the resistance increase of air preheater during the transformation of SCR denitrification system for ultra-low emission. In this paper, an SCR System of 300 MW unit after the ultra-low retrofit was selected for study purpose. The testing results are summarized as follows:(1) The NO_x at the outlet of unit denitrification was unevenly distributed. However, since the ammonia escape concentration limit was severely exceeded and the on-line ammonia escape monitoring meter readings were no longer eligible to represent the right values, NO_x concentration control would become more difficult and the increase of the resistance of the air preheater had been observed.(2) Excessively pursuing the ultra-low NO_x emission concentration may result in the drastic attenuation of the catalyst activities and some main chemical components. Then eventually severe deposition of ammonium bisulfate comes up on its surface. Therefore corresponding improvement plans are proposed. CEMS multi-point sampling transformation at denitrification outlet should be carried out to monitor NO_x concentration after ultra-low emission transformation. Both the ammonia injection optimization adjustment and the catalyst performance testing should be done on a regular basis to improve the effect of SCR denitrification device and the economy of denitrification operation.
Some major problems were encountered such as the difficulties to control NOx emission concentration and ammonia escape concentration as well as the resistance increase of air preheater during the transformation of SCR denitrification system for ultra-low emission. In this paper, an SCR System of 300 MW unit after the ultra-low retrofit was selected for study purpose. The testing results are summarized as follows:(1) The NO_x at the outlet of unit denitrification was unevenly distributed. However, since the ammonia escape concentration limit was severely exceeded and the on-line ammonia escape monitoring meter readings were no longer eligible to represent the right values, NO_x concentration control would become more difficult and the increase of the resistance of the air preheater had been observed.(2) Excessively pursuing the ultra-low NO_x emission concentration may result in the drastic attenuation of the catalyst activities and some main chemical components. Then eventually severe deposition of ammonium bisulfate comes up on its surface. Therefore corresponding improvement plans are proposed. CEMS multi-point sampling transformation at denitrification outlet should be carried out to monitor NO_x concentration after ultra-low emission transformation. Both the ammonia injection optimization adjustment and the catalyst performance testing should be done on a regular basis to improve the effect of SCR denitrification device and the economy of denitrification operation.
引文
[1]环境保护部,国家发展和改革委员会,国家能源局.关于印发《全面实施燃煤电厂超低排放和节能改造工作方案》的通知[A].环发[2015]164号,2015.
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[3]何军,马大卫,王正风,等.安徽省煤电机组超低排放改造及CEMS验收问题分析[J].中国电力,2018,51(7):170-177.HE Jun,MA Dawei,WANG Zhengfeng,et al.Analysis of the ultralow emission transformation and CEMS acceptance of coal-fired power plant in Anhui province[J].Electric Power,2018,51(7):170-177.
[4]王树民,余学海,顾永正,等.基于燃煤电厂“近零排放”的大气污染物排放限值探讨[J].环境科学研究,2018,31(6):975-984.WANG Shumin,YU Xuehai,GU Yongzheng,et al.Discussion of emission limits of air pollutants for‘near-zero emission’coal fired power plants[J].Research of Environmental Sciences,2018,31(6):975-984.
[5]郦建国,朱法华,孙雪丽.中国火电大气污染防治现状及挑战[J].中国电力,2018,51(6):2-10.LI Jianguo,ZHU Fahua,SUN Xueli.Current status and challenges of atmospheric pollution prevention and control of thermal power plants in China[J].Electric Power,2018,51(6):2-10.
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[7]钟礼金,宋玉宝.锅炉SCR烟气脱硝空气预热器堵塞原因及其解决措施[J].热电发电,2012,41(8):45-47,50.ZHONG Lijin,SONG Yubao.Air preheater blocking in boiler with SCR denitrification device:reason analysis and solutions[J].Thermal Power Generation,2012,41(8):45-47,50.
[8]孟小然,王金秀,陈进生,等.波纹板式SCR催化剂性能检测及其失活原因分析[J].中国电力,2016,49(1):141-145.MENG Xiaoran,WANG Jinxiu,CHEN Jinsheng,et al.Performance determination and deactivation analysis of corrugated SCRcatalysts[J].Electric Power,2016,49(1):141-145.
[9]马大卫,张其良,黄齐顺,等.超低排放改造后SCR出口NOx分布及氨逃逸浓度评估研究[J].中国电力,2017,50(5):168-171.MA Dawei,ZHANG Qiliang,HUANG Qishun,et al.Assessment of NOx distribution and ammonia escape concentration at SCR outlet after ultra-low emission retrofit[J].Electric Power,2017,50(5):168-171.
[10]萧嘉繁,谭厚章,刘鹤欣,等.某1 000 MW超超临界燃煤机组尾部烟道硫酸氢铵盐沉积分析[J].中国电力,2018,51(4):67-74.XIAO Jiafan,TAN Houzhang,LIU Hexin,et al.Analysis on ammonium sulfate deposition in tail flue of 1 000 MW ultrasupercritical coal-fired unit[J].Electric Power,2018,51(4):67-74.
[11]潘栋,李淑宏,景云辉,等.超低排放电站锅炉SCR脱硝装置的故障诊断及运行优化研究[J].中国电力,2017,50(3):41-45,64.PAN Dong,LI Shuhong,JING Yunhui,et al.Study on fault diagnosis and operation optimization for power plant SCR with ultralow emission[J].Electric Power,2017,50(3):41-45,64.
[12]滕农,段玖祥,郭阳.燃煤电厂烟气脱硝装置氨逃逸浓度的测定方法[J].电力科技与环保,2013,29(1):37-39.TENG Nong,DUAN Jiuxiang,GUO Yang.Determination method for the ammonia slip of flue gas denitrification equipment in coalfired power plants[J].Electric Power Technology and Environmental Protection,2013,29(1):37-39.
[13]王树民,宋畅,陈寅彪,等.燃煤电厂大气污染物"近零排放"技术研究及工程应用[J].环境科学研究,2015,28(4):487-494.WANG Shumin,SONG Chang,CHEN Yinbiao,et al.Technology research and engineering applications of near-zero air pollutant emission coal-fired power plants[J].Research of Environmental Sciences,2015,28(4):487-494.
[14]商雪松,陈进生,胡恭任.不同运行时间烟气脱硝催化剂性能对比分析[J].中国电力,2012,45(1):45-49,68.SHANG Xuesong,CHEN Jinsheng,HU Gongren.Comparative analysis of de-NOx catalysts with different operation-times[J].Electric Power,2012,45(1):45-49,68.
[15]马大卫,查智明,黄齐顺,等.蜂窝式脱硝催化剂化学成分分析方法建立及应用[J].东北电力技术,2018,39(7):40-42,45.MA Dawei,ZHA Zhiming,HUANG Qishun,et al.Establishment and application of chemical composition analysis method in honeycomb-type denitration catalyst[J].Northeast Electric Power Technology,2018,39(7):40-42,45.
[16]王树民,刘吉臻.燃煤电厂烟气污染物近零排放工程实践分析[J].中国电机工程学报,2016,36(22):6140-6147.WANG Shumin,LIU Jizhen.Investigation of near-zero air pollutant emission characteristics from coal-fired power plants[J].Proceedings of the CSEE,2016,36(22):6140-6147.
[17]毛奕升,吴智鹏,张孝天.火电厂SCR脱硝系统喷氨优化调整及烟气取样方法改进[J].中国电力,2017,50(4):167-171.MAO Yisheng,WU Zhipeng,ZHANG Xiaotian.Optimization and adjustment of ammonia injection system and improvement of flue gas sampling method for SCR denitrification system of thermal power plants[J].Electric Power,2017,50(4):167-171.
[2]朱法华,王临清.煤电超低排放的技术经济性与环境效益分析[J].环境保护,2014,42(21):28-33.ZHU Fahua,WANG Linqing.Analysis on technology-economy and environment benefit of ultra-low emission from coal-fired power units[J].Environmental Protection,2014,42(21):28-33.
[3]何军,马大卫,王正风,等.安徽省煤电机组超低排放改造及CEMS验收问题分析[J].中国电力,2018,51(7):170-177.HE Jun,MA Dawei,WANG Zhengfeng,et al.Analysis of the ultralow emission transformation and CEMS acceptance of coal-fired power plant in Anhui province[J].Electric Power,2018,51(7):170-177.
[4]王树民,余学海,顾永正,等.基于燃煤电厂“近零排放”的大气污染物排放限值探讨[J].环境科学研究,2018,31(6):975-984.WANG Shumin,YU Xuehai,GU Yongzheng,et al.Discussion of emission limits of air pollutants for‘near-zero emission’coal fired power plants[J].Research of Environmental Sciences,2018,31(6):975-984.
[5]郦建国,朱法华,孙雪丽.中国火电大气污染防治现状及挑战[J].中国电力,2018,51(6):2-10.LI Jianguo,ZHU Fahua,SUN Xueli.Current status and challenges of atmospheric pollution prevention and control of thermal power plants in China[J].Electric Power,2018,51(6):2-10.
[6]河北省环境保护厅,河北省质量技术监督局.钢铁工业大气污染物超低排放标准:DB 13/2169-2018[S].2018.
[7]钟礼金,宋玉宝.锅炉SCR烟气脱硝空气预热器堵塞原因及其解决措施[J].热电发电,2012,41(8):45-47,50.ZHONG Lijin,SONG Yubao.Air preheater blocking in boiler with SCR denitrification device:reason analysis and solutions[J].Thermal Power Generation,2012,41(8):45-47,50.
[8]孟小然,王金秀,陈进生,等.波纹板式SCR催化剂性能检测及其失活原因分析[J].中国电力,2016,49(1):141-145.MENG Xiaoran,WANG Jinxiu,CHEN Jinsheng,et al.Performance determination and deactivation analysis of corrugated SCRcatalysts[J].Electric Power,2016,49(1):141-145.
[9]马大卫,张其良,黄齐顺,等.超低排放改造后SCR出口NOx分布及氨逃逸浓度评估研究[J].中国电力,2017,50(5):168-171.MA Dawei,ZHANG Qiliang,HUANG Qishun,et al.Assessment of NOx distribution and ammonia escape concentration at SCR outlet after ultra-low emission retrofit[J].Electric Power,2017,50(5):168-171.
[10]萧嘉繁,谭厚章,刘鹤欣,等.某1 000 MW超超临界燃煤机组尾部烟道硫酸氢铵盐沉积分析[J].中国电力,2018,51(4):67-74.XIAO Jiafan,TAN Houzhang,LIU Hexin,et al.Analysis on ammonium sulfate deposition in tail flue of 1 000 MW ultrasupercritical coal-fired unit[J].Electric Power,2018,51(4):67-74.
[11]潘栋,李淑宏,景云辉,等.超低排放电站锅炉SCR脱硝装置的故障诊断及运行优化研究[J].中国电力,2017,50(3):41-45,64.PAN Dong,LI Shuhong,JING Yunhui,et al.Study on fault diagnosis and operation optimization for power plant SCR with ultralow emission[J].Electric Power,2017,50(3):41-45,64.
[12]滕农,段玖祥,郭阳.燃煤电厂烟气脱硝装置氨逃逸浓度的测定方法[J].电力科技与环保,2013,29(1):37-39.TENG Nong,DUAN Jiuxiang,GUO Yang.Determination method for the ammonia slip of flue gas denitrification equipment in coalfired power plants[J].Electric Power Technology and Environmental Protection,2013,29(1):37-39.
[13]王树民,宋畅,陈寅彪,等.燃煤电厂大气污染物"近零排放"技术研究及工程应用[J].环境科学研究,2015,28(4):487-494.WANG Shumin,SONG Chang,CHEN Yinbiao,et al.Technology research and engineering applications of near-zero air pollutant emission coal-fired power plants[J].Research of Environmental Sciences,2015,28(4):487-494.
[14]商雪松,陈进生,胡恭任.不同运行时间烟气脱硝催化剂性能对比分析[J].中国电力,2012,45(1):45-49,68.SHANG Xuesong,CHEN Jinsheng,HU Gongren.Comparative analysis of de-NOx catalysts with different operation-times[J].Electric Power,2012,45(1):45-49,68.
[15]马大卫,查智明,黄齐顺,等.蜂窝式脱硝催化剂化学成分分析方法建立及应用[J].东北电力技术,2018,39(7):40-42,45.MA Dawei,ZHA Zhiming,HUANG Qishun,et al.Establishment and application of chemical composition analysis method in honeycomb-type denitration catalyst[J].Northeast Electric Power Technology,2018,39(7):40-42,45.
[16]王树民,刘吉臻.燃煤电厂烟气污染物近零排放工程实践分析[J].中国电机工程学报,2016,36(22):6140-6147.WANG Shumin,LIU Jizhen.Investigation of near-zero air pollutant emission characteristics from coal-fired power plants[J].Proceedings of the CSEE,2016,36(22):6140-6147.
[17]毛奕升,吴智鹏,张孝天.火电厂SCR脱硝系统喷氨优化调整及烟气取样方法改进[J].中国电力,2017,50(4):167-171.MAO Yisheng,WU Zhipeng,ZHANG Xiaotian.Optimization and adjustment of ammonia injection system and improvement of flue gas sampling method for SCR denitrification system of thermal power plants[J].Electric Power,2017,50(4):167-171.