660 MW超低排放燃煤电站汞分布特征研究
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摘要
对某660 MW超低排放燃煤电站进行汞形态和浓度监测,实验结果表明:在SCR前烟气中,汞主要以单质游离态存在,SCR催化剂对Hg~0氧化率约为20.22%.烟冷器内Hg~0向Hg_p和Hg~(2+)转化,Hg_p浓度增加72.18%,Hg~(2+)浓度增加55.40%.低温电除尘不仅可以脱除Hg_p,对Hg~0和Hg~(2+)也具有协同脱除作用,Hg~0浓度下降47.14%,Hg~(2+)浓度下降68.70%.经过湿法脱硫后Hg~0浓度由0.37μg·m~(-3)升高到0.86μg·m~(-3),Hg~(2+)在湿法脱硫装置内被还原为Hg~0.大气汞排放浓度在0.82～0.95μg·m~(-3)之间,远低于标准要求.超低排放电站产生的汞大部分进入粉煤灰(68.35%),大气排放的汞为21.20%,进入石膏中的汞为4.87%,进入脱硫废水处理站固废5.53%.超低排放环保设备总的协同脱汞效率为78.77%,大气汞排放因子(EF_煤、EF_电)分别为6.07μg·kg~(-1)和1.70μg·kW~(-1)·h~(-1).
The speciation and quantity of mercury were monitored and tested in a 660 MW coal-fired power plant with ultra-low air pollutant control technologies. The results show that mercury is existed as elemental mercury(Hg~0) before SCR and 20.22% elemental mercury(Hg~0) are converted as oxidized mercury(Hg~(2+)) by SCR catalyst. And Majority of Hg~0 in low-temperature economizer was converted to Hg_p and Hg~(2+), the concentration of Hg_p and Hg~(2+) increased by 72.18% and 55.40% respectively. Low-low temperature ESP has the significantly synergistic removal of Hg~0 and Hg~(2+), the concentration of Hg~0 and Hg~(2+) decreased by 47.14% and 68.70% respectively. Besides, The concentration of Hg~0 increase from 0.37 μg·m~(-3) to 0.86 μg·m~(-3) after WFGD, since Hg~(2+) is reduced to Hg~0 in WFGD. The concentration of mercury emission is about 0.82～0.95 μg·m~(-3), which is far below the national standards. Most of the mercury is left in fly ash, accounted for 68.35%, the rest of mercury is lest in the atmospheric emission with 21.20%, gypsum with 4.87%, and the desulfurization wastewater with 5.53%. In total, the mercury removal efficiency of ultra-low emission environmental protection equipment is 78.77%, Emission factors of mercury for coal and electricity of the power plant are 6.07 μg·kg~(-1) and 1.70 μg·kW~(-1)·h~(-1)respectively.
The speciation and quantity of mercury were monitored and tested in a 660 MW coal-fired power plant with ultra-low air pollutant control technologies. The results show that mercury is existed as elemental mercury(Hg~0) before SCR and 20.22% elemental mercury(Hg~0) are converted as oxidized mercury(Hg~(2+)) by SCR catalyst. And Majority of Hg~0 in low-temperature economizer was converted to Hg_p and Hg~(2+), the concentration of Hg_p and Hg~(2+) increased by 72.18% and 55.40% respectively. Low-low temperature ESP has the significantly synergistic removal of Hg~0 and Hg~(2+), the concentration of Hg~0 and Hg~(2+) decreased by 47.14% and 68.70% respectively. Besides, The concentration of Hg~0 increase from 0.37 μg·m~(-3) to 0.86 μg·m~(-3) after WFGD, since Hg~(2+) is reduced to Hg~0 in WFGD. The concentration of mercury emission is about 0.82～0.95 μg·m~(-3), which is far below the national standards. Most of the mercury is left in fly ash, accounted for 68.35%, the rest of mercury is lest in the atmospheric emission with 21.20%, gypsum with 4.87%, and the desulfurization wastewater with 5.53%. In total, the mercury removal efficiency of ultra-low emission environmental protection equipment is 78.77%, Emission factors of mercury for coal and electricity of the power plant are 6.07 μg·kg~(-1) and 1.70 μg·kW~(-1)·h~(-1)respectively.
引文
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全国煤炭标准化技术委员会.2009.GB_475_2008商品煤样人工采取方法[S].北京:中国标准出版社
任建莉,周劲松,骆仲泱,等.2002.煤中汞燃烧过程析出规律试验研究[J].环境科学学报,22(3):289-293
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Yokoyama T, Asakura K, Matsuda H, et al.2000.Mercury emissions from a coal-fired power plant in Japan[J]. The Science of the Total Environment, 259(1/3): 97-103
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Wu C L, Cao Y, He C C, et al.2010.study of elemental mercury re-emission through a lab-scale simulated）scrubber[J]. Fuel,89:2072-2080
Wu Y,Wang S X,Streets D G,et al.2006.Trends in anthropogenic mercury emissions in China from 1995 to 2003[J].Environmental Science and Technology,40:5312-5318
吴晓云,郑有飞,林克思.2015.我国大气环境中汞污染现状[J].中国环境科学,35(9):2623-2635
Yang H M, Pan W P.2007.Transformation of mercury speciation through the SCR system in power plants[J]. Journal of environmental sciences (China),19(2): 181-184
Zhuang Y.2007.Impacts of acid gases on mercury oxidation across SCR catalyst[J].Fuel Processing Technology,88(10):929-934
尹连庆,王晶.2009.粉尘比电阻对电除尘的影响及改进措施研究[J].电力环境保护,25(5):34-37
殷立宝,禚玉群,徐齐胜,等.2013.中国燃煤电厂汞排放规律[J].中国电机工程学报,33(29):1-9
英国石油集团公司.2017.BP世界能源统计年鉴2017[EB/ OL].https://www.bp.com/zh_cn/china/reports-and-publications/_bp_2017-_.html
Yoshio N,Satoshi N,Yasuhiro T,et al.2011.MHI high efficiency system-proven technology for multipollutant removal[R].Hiroshima Research & Development Center,1-11
Zhang L, Wang S X, Wang L, et al. 2015.Updated emission inventories for speciated atmospheric mercury from anthropogenic sources in China[J]. Environmental Science and Technology, 49(5): 3185-3194
赵继尧,唐修义,黄文辉.2002.中国煤中微量元素的丰度[J].中国煤田地质,14(Z1):5-13
中华人民共和国国家统计局.2017.中国统计年鉴[OL].北京:中国统计出版社.Http:/ /www.mwr.gov.cn/zwzc/hygb
Eom Y,Jeon S H,Ngo T A,et al.2008.Heterogeneous mercury reaction on a selective catalytic reduction (SCR) catalyst[J].Catalysis Letter,121(3/4):219-225
Eswaran S,Stenger H G.2005.Understanding mercury conversion in selective catalytic reduction (SCR) catalysts[J].Energy & Fuels,19(6):2328-2334
Eswaran S,Stenger H G.2008.Effect of halogens on mercury conversion in SCR catalysts[J].Fuel Processing Technology, 89(11):1153-1159
国家环境保护部.2011.GB13223—2011 火电厂大气污染物排放标准[S].北京:中国标准出版社
惠霂霖,张磊,王书肖,等.2017.中国燃煤部门大气汞排放协同控制效果评估及未来预测[J].环境科学学报,37(1): 11-22
靳星.2013.静电除尘器内细颗粒物脱除特性的技术基础研究[D].北京:清华大学
Kamata H, Yukimura A.2012.Catalyst aging in a coal combustion flue gas for mercury oxidation[J].Fuel Processing Technology, 104(104):295-299
Li J R,He C,Shang X S,et al.2012.Oxidation efficiency of elemental mercury in flue gas by SCR De-NOx catalysts[J].Journal of Fuel Chemistry and Technology,40(2):241-246
李舒,高伟,王书肖,等.2016.上海崇明地区大气分形态汞污染特征 [J].环境科学学报,37(9): 3290-3297
Nian T, Pan S W.2013.Study on mercury emission and migration from large-scale pulverized coal fired boilers[J].Journal of Fuel Chemistry & Technology,41(4):484-490
Omine N, Romero C E, Kikkawa H, et al.2012.Study of elemental mercury re-emission in a simulated wet）scrubber[J]. Fuel,91(1):93-101
Pacyna E G.2006.Global anthropogenic mercury emission inventory for 2000 [J].Atmospheric Environment,40(22):4048-4063
Pacyna E G.2010.Global emission of mercury to the atmosphere from anthropogenic sources in 2005 and projections to 2020[J].Atmospheric Environment,44(20):2487-2499
Pirrone N.2010.Global mercury emissions to the atmosphere from anthropogenic and natural sources[J].Atmospheric Chemistry & smp; Physics Discussions,10(13):5951-5964
全国煤炭标准化技术委员会.2009.GB_475_2008商品煤样人工采取方法[S].北京:中国标准出版社
任建莉,周劲松,骆仲泱,等.2002.煤中汞燃烧过程析出规律试验研究[J].环境科学学报,22(3):289-293
Senior C L. 2006.Oxidation of mercury across selective catalytic reduction catalysts in coal-fired power plants[J]. Air Repair, 56(1):23-31
Srivastava R K, Hutson N, Martin B, et al.2006.Control of mercury emissions from coal-fired electric utility boilers）[J]. Environmental Science & Technology,40(5):1385-1393
Yokoyama T, Asakura K, Matsuda H, et al.2000.Mercury emissions from a coal-fired power plant in Japan[J]. The Science of the Total Environment, 259(1/3): 97-103
王铮,薛建明,许月阳,等.2013.选择性催化还原协同控制燃煤烟气中汞排放效果影响因素研究[J].中国电机工程学报,33(14):32-37
Wu C L, Cao Y, He C C, et al.2010.study of elemental mercury re-emission through a lab-scale simulated）scrubber[J]. Fuel,89:2072-2080
Wu Y,Wang S X,Streets D G,et al.2006.Trends in anthropogenic mercury emissions in China from 1995 to 2003[J].Environmental Science and Technology,40:5312-5318
吴晓云,郑有飞,林克思.2015.我国大气环境中汞污染现状[J].中国环境科学,35(9):2623-2635
Yang H M, Pan W P.2007.Transformation of mercury speciation through the SCR system in power plants[J]. Journal of environmental sciences (China),19(2): 181-184
Zhuang Y.2007.Impacts of acid gases on mercury oxidation across SCR catalyst[J].Fuel Processing Technology,88(10):929-934
尹连庆,王晶.2009.粉尘比电阻对电除尘的影响及改进措施研究[J].电力环境保护,25(5):34-37
殷立宝,禚玉群,徐齐胜,等.2013.中国燃煤电厂汞排放规律[J].中国电机工程学报,33(29):1-9
英国石油集团公司.2017.BP世界能源统计年鉴2017[EB/ OL].https://www.bp.com/zh_cn/china/reports-and-publications/_bp_2017-_.html
Yoshio N,Satoshi N,Yasuhiro T,et al.2011.MHI high efficiency system-proven technology for multipollutant removal[R].Hiroshima Research & Development Center,1-11
Zhang L, Wang S X, Wang L, et al. 2015.Updated emission inventories for speciated atmospheric mercury from anthropogenic sources in China[J]. Environmental Science and Technology, 49(5): 3185-3194
赵继尧,唐修义,黄文辉.2002.中国煤中微量元素的丰度[J].中国煤田地质,14(Z1):5-13
中华人民共和国国家统计局.2017.中国统计年鉴[OL].北京:中国统计出版社.Http:/ /www.mwr.gov.cn/zwzc/hygb