喷射点位及温度对超低排放电厂活性炭吸附脱汞的影响
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摘要
针对活性炭对燃煤电厂烟气中汞污染控制的影响,在实验室和超低排放电厂开展了烟气脱汞研究,考察了活性炭吸附反应温度、停留时间对吸附效果的影响。结果表明,在固定床中获得了适用于燃煤电厂喷射吸附的优化吸附温度,120℃反应条件下,活性炭的吸附能力最强。在300MW超低排放燃煤机组开展了活性炭喷射吸附脱汞实验,未实施活性炭喷射前湿式静电除尘器(wet electrostatic precipitator,WESP)后排放浓度在0.50～0.58mg/m~3之间;在选择性催化还原装置(selective catalytic reduction device,SCR)后空预器(airpreheater,APH)前(350℃)和APH后低温省煤器(low temperature economizer,LTE)前(121℃) 2个点位进行了活性炭喷射实验,其中在APH后LTE前喷射活性炭后,WESP后浓度最低可达到0.11mg/m~3。实验同时表明,温度对活性炭吸附脱汞的影响要强于停留时间的影响,相比SCR后喷射脱汞,在LTE前进行活性炭的喷射对烟气中汞的脱除效率更高。
For better understanding the effect of activated carbon on mercury emission in the flue gas of coal-fired power plant, mercury removal from flue gas was studied in the laboratory scale and the ultra-low emission power plant. The effects of temperature and residence time on the mercury captured using activated carbon were investigated. Results from a laboratory scale fixed bed reactor indicated that the optimal mercury captured temperature is 120℃. Activated carbon injection and mercury removal experiments were carried out in 300 MW ultra-low emission coal-fired power plant, and the mercury emission concentration of wet electrostatic precipitator(WESP) was 0.50～0.58mg/m~3 before activated carbon injection. Activated carbon injection experiments were also carried out at two points. The first location was after selective catalytic reduction device(SCR)and before air preheater(APH)(350℃). The second location was before the low temperature economizer(LTE)and after the APH(121℃). The mercury concentration after WESP could reach as low as 0.11mg/m~3, when the activated carbon was injected before the LTE. The results show that the effect of temperature on the adsorption and removal of mercury using activated carbon is more important than that of residence time.Compared with the injection after SCR, the removal efficiency of mercury in the flue gas is higher by the injection of activated carbon in front of the LTE.
For better understanding the effect of activated carbon on mercury emission in the flue gas of coal-fired power plant, mercury removal from flue gas was studied in the laboratory scale and the ultra-low emission power plant. The effects of temperature and residence time on the mercury captured using activated carbon were investigated. Results from a laboratory scale fixed bed reactor indicated that the optimal mercury captured temperature is 120℃. Activated carbon injection and mercury removal experiments were carried out in 300 MW ultra-low emission coal-fired power plant, and the mercury emission concentration of wet electrostatic precipitator(WESP) was 0.50～0.58mg/m~3 before activated carbon injection. Activated carbon injection experiments were also carried out at two points. The first location was after selective catalytic reduction device(SCR)and before air preheater(APH)(350℃). The second location was before the low temperature economizer(LTE)and after the APH(121℃). The mercury concentration after WESP could reach as low as 0.11mg/m~3, when the activated carbon was injected before the LTE. The results show that the effect of temperature on the adsorption and removal of mercury using activated carbon is more important than that of residence time.Compared with the injection after SCR, the removal efficiency of mercury in the flue gas is higher by the injection of activated carbon in front of the LTE.
引文
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[23]中华人民共和国环境保护部.HJ 917-2017固定污染源废气气态汞的测定活性炭吸附/热裂解原子吸收分光光度法[S].北京:中国环境科学出版社,2017.Ministry of Environmental Protection of the People's Republic of China.HJ 917-2017 Stationary source emission-Determination of total gaseous mercury-carbon sorbent traps/thermal cracking atomic absorption spectrophotometric method[S].Beijing:China Environmental Science Press,2017(in Chinese).
[24]刘倩雁,张锦红,赵丽丽,等.活性炭对烟气汞吸附特性的实验研究[J].上海电力学院学报,2012,28(6):541-544.Liu Qianyan,Zhang Jinhong,Zhao Lili,et al.Experimental study of activated carbon adsorption characteristics on flue gas mercury[J].Journal of Shanghai University of Electric Power,2012,28(6):541-544(in Chinese).
[25]Zhang Yongsheng,Shang Panfeng,Wang Jiawei,et al.Trace element(Hg,As,Cr,Cd,Pb)distribution and speciation in coal-fired power plants[J].Fuel,2017,208:647-654.
[2]Zhong Longchun,Li Wenhan,Zhang Yongsheng,et al.Kinetic studies of mercury adsorption in activated carbon modified by iodine steam vapor deposition method[J].Fuel,2017,188:343-351.
[3]Li Guoliang,Wu Qingru,Wang Shuxiao,et al.Improving flue gas mercury removal in waste incinerators by optimization of carbon injection rate[J].Environmental Science&Technology,2018,52(4):1940-1945.
[4]Zhong Longchun,Zhang Yongsheng,Ji Yong,et al.Synthesis of activated carbon from coal pitch for mercury removal in coal-fired power plants[J].Journal of Thermal Analysis and Calorimetry,2016,123(1):851-860.
[5]中国环境科学研究院,国电环境保护研究院.GB 13223-2011火电厂大气污染物排放标准[S].北京:中国环境科学出版社,2012.Chinese Research Academy of Environmental Sciences,Research Institute of Environmental Protection of Power Station.GB 13223-2011 Emission standard of air pollutants for thermal power plants[S].Beijing:China Environmental Science Press,2012(in Chinese).
[6]中国人大网.关于汞的水俣公约(中文本)[Z].2017.The People’s Congress of China.Minamata convention on mercur(Chinese version)[Z].2017(in Chinese).
[7]潘伟平,张永生,李文瀚,等.燃煤汞污染监测及控制技术[J].科技导报,2014,32(33):57-60.Pan Weiping,Zhang Yongsheng,Li Wenhan,et al.Mercury monitoring and controlling technologies for coal power plants[J].Science&Technology Review,2014,32(33):57-60(in Chinese).
[8]宋畅,张翼,郝剑,等.燃煤电厂超低排放改造前后汞污染排放特征[J].环境科学研究,2017,30(5):672-677.Song Chang,Zhang Yi,Hao Jian,et al.Mercury emission characteristics from coal-fired power plant before and after ultra-low emission retrofitting[J].Research of Environmental Sciences,2017,30(5):672-677(in Chinese).
[9]郑楚光,张军营,赵永椿,等.煤燃烧汞的排放及控制[M].北京:科学出版社,2010.Zheng Chuguang,Zhang Junying,Zhao Yongchun,et al.Emission and control of mercury from coal combustion[M].Beijing:Science Press,2010(in Chinese).
[10]Pavlish J H,Holmes M J,Benson S A,et al.Application of sorbents for mercury control for utilities burning lignite coal[J].Fuel Processing Technology,2004,85(6-7):563-576.
[11]Glesmann S,Mimna R.The state of U.S.mercury control in response to MATS[EB/OL].2015(2015-04-01).http://www.powermag.com/the-state-of-u-s-merc ury-control-in-response-to-mats/?pagenum=1.
[12]Brown T,Lissianski V.First full-scale demonstration of mercury control in Alberta[J].Fuel Processing Technology,2009,90(11):1412-1418.
[13]Derenne S,Sartorelli P,Bustard J,et al.TOXECON clean coal demonstration for mercury and multi-pollutant control at the Presque Isle Power Plant[J].Fuel Processing Technology,2009,90(11):1400-1405.
[14]Serre S D,Gullett B K,Ghorishi S B.Entrained-flow adsorption of mercury using activated carbon[J].Journal of the Air&Waste Management Association,2001,51(5):733-741.
[15]洪亚光,段钰锋,朱纯,等.载溴高硫石油焦活性炭脱汞实验研究[J].中国电机工程学报,2014,34(11):1762-1768.Hong Yaguang,Duan Yufeng,Zhu Chun,et al.Experimental study on mercury removal of high-sulfur petroleum coke activated carbon impregnated with bromine[J].Proceedings of the CSEE,2014,34(11):1762-1768(in Chinese).
[16]董守亮,毛雁翎.燃煤电站烟道内活性炭喷射对汞脱除的模拟研究[J].计算机与应用化学,2016,33(3):365-368.Dong Shouliang,MaoYanling.Activated carbon injection for mercury removal simulation of coal-fired power plant flue inside[J].Computers and Applied Chemistry,2016,33(3):365-368(in Chinese).
[17]周强,段钰锋,洪亚光,等.模拟烟气活性炭喷射脱汞实验研究[J].中国电机工程学报,2013,33(35):36-43.Zhou Qiang,Duan Yufeng,Hong Yaguang,et al.Experimental study on mercury capture using activated carbon injection in simulated flue gas[J].Proceedings of the CSEE,2013,33(35):36-43(in Chinese).
[18]胡长兴,周劲松,骆仲泱,等.烟气脱汞过程中活性炭喷射量的影响因素[J].化工学报,2005,56(11):2172-2177.Hu Changxing,Zhou Jinsong,Luo Zhongyang,et al.Factors affecting amount of activated carbon injection for flue gas mercury control[J].Journal of Chemical Industry and Engineering(China),2005,56(11):2172-2177(in Chinese).
[19]Sjostrom S,Durham M,Bustard C J,et al.Activated carbon injection for mercury control:Overview[J].Fuel,2010,89(6):1320-1322.
[20]Zhao Bingtao,Zhang Zhongxiao,Jing Jing,et al.Simulation of mercury capture by sorbent injection using a simplified model[J].Journal of Hazardous Materials,2009,170(2-3):1179-1185.
[21]史晓宏,温武斌,薛志钢,等.300MW燃煤电厂溴化钙添加与烟气脱硫协同脱汞技术研究[J].动力工程学报,2014,34(6):482-486.Shi Xiaohong,Wen Wubin,Xue Zhigang,et al.Study on simultaneous desulfurization and demercurization with CaBr2 in a 300 MW coal-fired power plant[J].Journal of Chinese Society of Power Engineering,2014,34(6):482-486(in Chinese).
[22]钟犁,肖平,江建忠,等.燃煤锅炉氧化协同脱汞试验研究[J].热力发电,2016,45(2):52-58,63.Zhong Li,Xiao Ping,Jiang Jianzhong,et al.Experimental study on mercury removal by oxidation in a coal-fired boiler[J].Thermal Power Generation,2016,45(2):52-58,63(in Chinese).
[23]中华人民共和国环境保护部.HJ 917-2017固定污染源废气气态汞的测定活性炭吸附/热裂解原子吸收分光光度法[S].北京:中国环境科学出版社,2017.Ministry of Environmental Protection of the People's Republic of China.HJ 917-2017 Stationary source emission-Determination of total gaseous mercury-carbon sorbent traps/thermal cracking atomic absorption spectrophotometric method[S].Beijing:China Environmental Science Press,2017(in Chinese).
[24]刘倩雁,张锦红,赵丽丽,等.活性炭对烟气汞吸附特性的实验研究[J].上海电力学院学报,2012,28(6):541-544.Liu Qianyan,Zhang Jinhong,Zhao Lili,et al.Experimental study of activated carbon adsorption characteristics on flue gas mercury[J].Journal of Shanghai University of Electric Power,2012,28(6):541-544(in Chinese).
[25]Zhang Yongsheng,Shang Panfeng,Wang Jiawei,et al.Trace element(Hg,As,Cr,Cd,Pb)distribution and speciation in coal-fired power plants[J].Fuel,2017,208:647-654.