溴元素改性椰壳活性炭对实际燃煤烟气的脱汞性能
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摘要
以椰壳活性炭(YAC)为原料,通过NH4Br溶液浸渍改性,制备了溴素改性椰壳活性炭脱汞吸附剂(YAC-Br)。在固定床实验台上开展了YAC和YAC-Br的汞脱除实验,主要研究了入口汞(Hg0)浓度对YAC-Br脱汞性能的影响,并结合BET、SEM、XRF等表征手段分析了YAC-Br的脱汞原理。在0.3MW燃煤循环流化床锅炉上对YAC-Br进行了烟气管道喷射吸附剂脱汞(ACI)实验,验证了其在实际燃煤烟气中对汞的脱除效果。结果表明:改性过程不会破坏椰壳活性炭原有的孔隙结构和微孔容积,而会使活性炭表面更加平整;化学改性后活性炭表面Br负载量提高,成为Hg0的主要活性吸附位。固定床实验结果说明:改性后椰壳活性炭的初始汞吸附效率和单位累积汞吸附量分别提高了6.02倍和21.8倍,吸附效率随汞浓度增大而降低。0.3MW燃煤循环流化床实验结果表明:改性后椰壳活性炭对元素汞和氧化汞均有很好的脱除作用,脱汞效率随着吸附剂喷射量的增加而增加,当喷射量为0.7kg/h时,脱汞效率可达到76.38%。
The bromine-modified coconut shell activated carbon(YAC-Br) for mercury removal adsorbent was prepared by using the coconut shell activated carbon(YAC) as raw material and impregnating with NH4 Br solution. The mercury removal experiments of YAC and YAC-Br were carried out in a fixed bed. The effects of initial mercury(Hg0) concentration on the mercury removal performance of YAC-Br were studied. The principle of mercury removal from YAC-Br was analyzed, combined with characterization methods such as BET, SEM and XRF. Activated carbon injection(ACI) experiments were carried out on a 0.3 MW coal-fired circulating fluidized bed boiler to study the adsorption effect of YACBr on mercury in real flue gas. The results showed that the modification process has no damage on the original pore structure and pore volume of YAC, but it makes the surface smoother. After chemical modification, the Br-loading capacity on the activated carbon surface increases and becomes the main active adsorption site of Hg0. The results of the fixed bed experiments showed that the initial mercury adsorption efficiency and unit cumulative mercury adsorption capacity of YAC-Br increases by 6.02 times and 21.8 times, respectively. The adsorption efficiency decreases with the increase of mercury initial concentration. The results of the 0.3 MW circulating fluidized bed coal combustion experiments showed that YAC-Br has good adsorption to elemental mercury and oxidized mercury. The mercury removal efficiency increases with the increase of the adsorbent injection amount. When the injection amount was0.7 kg/h, the mercury removal efficiency reached 76.38%.
The bromine-modified coconut shell activated carbon(YAC-Br) for mercury removal adsorbent was prepared by using the coconut shell activated carbon(YAC) as raw material and impregnating with NH4 Br solution. The mercury removal experiments of YAC and YAC-Br were carried out in a fixed bed. The effects of initial mercury(Hg0) concentration on the mercury removal performance of YAC-Br were studied. The principle of mercury removal from YAC-Br was analyzed, combined with characterization methods such as BET, SEM and XRF. Activated carbon injection(ACI) experiments were carried out on a 0.3 MW coal-fired circulating fluidized bed boiler to study the adsorption effect of YACBr on mercury in real flue gas. The results showed that the modification process has no damage on the original pore structure and pore volume of YAC, but it makes the surface smoother. After chemical modification, the Br-loading capacity on the activated carbon surface increases and becomes the main active adsorption site of Hg0. The results of the fixed bed experiments showed that the initial mercury adsorption efficiency and unit cumulative mercury adsorption capacity of YAC-Br increases by 6.02 times and 21.8 times, respectively. The adsorption efficiency decreases with the increase of mercury initial concentration. The results of the 0.3 MW circulating fluidized bed coal combustion experiments showed that YAC-Br has good adsorption to elemental mercury and oxidized mercury. The mercury removal efficiency increases with the increase of the adsorbent injection amount. When the injection amount was0.7 kg/h, the mercury removal efficiency reached 76.38%.
引文
[1] XU W Q, WANG H R, ZHU T Y, et al. Mercury removal from coal combustion flue gas by modified fly ash[J]. Journal of Environmental Science, 2013, 25(2):393-398.
[2]吴福全,梁柱,王雅玲,等.全球大气汞排放清单研究现状[J].环境监测管理与技术, 2015, 27(3):18-21.WU Fuquan, LIANG Zhu, WANG Yaling, et al. Study on the status of global atmospheric mercury emission inventory[J]. The Administration and Technique of Environmental Monitoring, 2015, 27(3):18-21.
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[4]王起超,沈文国,麻壮伟.中国燃煤汞排放量估算[J].中国环境科学,1999, 19(4):318-321.WANG Qichao, SHEN Wenguo, MA Zhuangwei. The emission of mercury from coal combustion in China[J]. China Environmental Science, 1999, 19(4):318-321.
[5]吴晓云,郑有飞,林克思.我国大气坏境中汞污染现状[J].中国环境科学, 2015, 35(9):2623-2635.WU Xiaoyun, ZHENG Youfei, LIN Kesi. Chinese atmosphere mercury pollution status[J]. China Environmental Science, 2015, 35(9):2623-2635.
[6]朱纯,段钰锋,尹建军,等.卤化铵盐改性生物质稻壳焦的汞吸附特性[J].东南大学学报(自然科学版), 2013, 43(1):99-104.ZhU Chun, DUAN Yufeng, YIN Jianjun, et al. Mercury adsorption by rice husk char sorbents modified by ammonium halide[J]. Journal of Southeast University(Natural Science Edition), 2013, 43(1):99-104.
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[8]北京市环境保护局,北京市质量技术监督局.锅炉大气污染物排放标准:DB11/139—2015[S].北京, 2015.Beijing Municipal Environmental Protection Bureau, Beijing Municipal Bureau of Quality and Technical Supervision. Emission standard of air pollutants for boilers:DB 11/139—2015[S]. Beijing,2015.
[9]段钰锋,尹建军,冒咏秋,等.改性生物质稻杆焦脱除烟气中汞的实验研究[J].工程热物理学报, 2013, 34(3):581-585.DUAN Yufeng, YIN Jianjun, MAO Yongqiu, et al. Mercury removal from simulated flue gas by modified rice straw char[J]. Journal of Engineering Thermophysics, 2013, 34(3):581-585.
[10]王晨平,段钰锋,佘敏,等. SO2活化改性石油焦吸附剂的汞吸附特性[J].化工学报, 2017, 68(12):4764-4773.WANG Chenping, DUAN Yufeng, SHE Min, et al. Mercury adsorption characteristics of petroleum coke activated[J]. CIESC Journal, 2017, 68(12):4764-4773.
[11]佘敏,段钰锋,朱纯,等.CO2/H3PO4活化与NH4Br改性稻壳焦的脱汞性能实验研究[J].东南大学学报(自然科学版), 2014, 44(2):321-327.SHE Min, DUAN Yufeng, ZHU Chun,et al. Experimental study on mercury adsorption performances of rice husk chars activated by CO2/H3PO4and modified by NH4Br[J]. Journal of Southeast University(Natural Science Edition), 2014, 44(2):321-327.
[12]洪亚光,段钰锋,朱纯,等.硫改性椰壳活性炭管道喷射脱汞实验研究[J].东南大学学报(自然科学版), 2015, 45(3):521-525.HONG Yaguang, DUAN Yufeng, ZHU Chun, et al. Experimental study on mercury adsorption of S-impregnated coconut shell activated carbon by duct injection[J]. Journal of Southeast University(Natural Science Edition), 2015, 45(3):521-525.
[13]许静,段钰锋,姚婷,等.可再生脱汞吸附剂的研究进展[J].化工进展, 2017, 36(1):442-448.XU Jing, DUAN Yufeng, YAO Ting, et al. Research progress on regenerable mercury sorbents[J]. Chemical Industry and Engineering Progress, 2017, 36(1):442-448.
[14]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]. CIESC Journal, 2005, 56(11):2172-2177.
[15]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. Exprimental study on mercury using activated carbon injection in simulated flue gas[J]. Proceedings of the CSEE, 2013, 33(35):36-43.
[16]姚婷,洪亚光,段钰锋,等.KI改性凹凸棒管道喷射脱汞实验研究[J].中国电机工程学报, 2015, 35(22):5787-5792.YAO Ting, HONG Yaguang, DUAN Yufeng, et al. Experimental study on mercury removal by duct injection with KI-impregnated attapulgite[J]. Proceedings of the CSEE, 2015, 35(22):5787-5792.
[17]赵鹏飞,郭欣,郑楚光.载银稻壳基吸附剂的制备与表征及其脱除Hg0的实验研究[J].中国电机工程学报, 2012, 32(5):61-67.ZHAO Pengfei, GUO Xin, ZHENG Chuguang. Synthesis and characterizations of silver-loaded rice husk ash sorbents and their performance for elemental mercury removal[J]. Proceedings of the CSEE,2012,32(5):61-67.
[18] WANG Shuxiao, ZHANG Lei, WU Ye, et al. Synergistic mercury removal by convention pollutant control strategies for coal-fired power plants in China[J]. Journal of the Air&Waste Management Association, 2010, 60(6):722-730.
[19]孙巍,宴乃强,贾金平.载溴活性炭去除烟气中的单质汞[J].中国环境科学, 2006, 26(3):257-261.SUN Wei, YAN Naiqiang, JIA Jinping. Removal of elemental mercury in flue gas by brominated activated carbon[J]. China Environmental Science, 2006, 26(3):257-261.
[20] KWON S, BORGUET E, VIDIC R D. Impact of surface heterogeneity on mercury uptake by carbonaceous sorbents under UHV and atmospheric pressure[J]. Environmental Science&Technology, 2002,36(19):41624169.
[21] KRISHAN S V, GULLETT B K, JOZEWICZ W, et al. Sorption of elemental mercury by activated acrbons[J]. Environmental Science&Technology, 1994, 28(8):1506-1512.
[22] ZENG H C, JIN F, GUO J. Removal of elemental mercury from coal combustion flue gas by chloride-impregnated activated carbon[J].Fuel, 2004, 83(1):143-146.
[23]高正阳,杨维结.卤素改性活性炭氧化单质汞的机理研究[J].工程热物理学报, 2017, 38(2):381-385.GAO Zhengyang, YANG Weijie. The study of reaction mechanism of mercury oxidation on halogenated activated carbon[J]. Journal of Engineering Thermophysics, 2017, 38(2):381-385.
[24] WANG S X, ZHANG L, LI G H, et al. Mercury emission and speciation of coal-fired power plants in China[J]. Atmospheric Chemistry and Physics, 2010, 10(3):1183-1192.
[25]杜雯,殷立宝,禚玉群,等. 100MW燃煤电厂非碳基吸附剂喷射脱汞实验研究[J].化工学报, 2014, 65(11):4413-4419.DU Wen, YIN libao, ZHUO Yuqun, et al. Experimental study on mercury capture using non-carbon sorbents in 100MW coal-fired power plant[J]. CIESC Journal, 2014, 65(11):4413-4419.
[26] JONES A P, HOFFMANN J W, SMITH D N, FEELEY T J, et al. DOE/NET’s phaseⅡmercury control technology field testing program:preliminary economic analysis of activated carbon injection[J].Environmental Science&Technology, 2007, 41(4):1365-1371.
[2]吴福全,梁柱,王雅玲,等.全球大气汞排放清单研究现状[J].环境监测管理与技术, 2015, 27(3):18-21.WU Fuquan, LIANG Zhu, WANG Yaling, et al. Study on the status of global atmospheric mercury emission inventory[J]. The Administration and Technique of Environmental Monitoring, 2015, 27(3):18-21.
[3]黄文辉,杨宜春.中国煤中的汞[J].中国煤田地质, 2002(14):37-40.HUANG Wenhui, YANG Yichun. Mercury in Chinese coal[J]. Coal Geology of China, 2002(14):37-40.
[4]王起超,沈文国,麻壮伟.中国燃煤汞排放量估算[J].中国环境科学,1999, 19(4):318-321.WANG Qichao, SHEN Wenguo, MA Zhuangwei. The emission of mercury from coal combustion in China[J]. China Environmental Science, 1999, 19(4):318-321.
[5]吴晓云,郑有飞,林克思.我国大气坏境中汞污染现状[J].中国环境科学, 2015, 35(9):2623-2635.WU Xiaoyun, ZHENG Youfei, LIN Kesi. Chinese atmosphere mercury pollution status[J]. China Environmental Science, 2015, 35(9):2623-2635.
[6]朱纯,段钰锋,尹建军,等.卤化铵盐改性生物质稻壳焦的汞吸附特性[J].东南大学学报(自然科学版), 2013, 43(1):99-104.ZhU Chun, DUAN Yufeng, YIN Jianjun, et al. Mercury adsorption by rice husk char sorbents modified by ammonium halide[J]. Journal of Southeast University(Natural Science Edition), 2013, 43(1):99-104.
[7]环境保护部,国家质量监督检验检疫总局.火电厂大气污染物排放标准:GB13223—2011[S].北京:中国环境科学出版社, 2011.Ministry of Environmental Protection, General Administration of Quality Supervision, Inspection and Quarantine of the People’s Republic of China. Emission standard of air pollutants for thermal power plants:GB 13223—2011[S]. Beijing:China Environmental Science Press, 2011.
[8]北京市环境保护局,北京市质量技术监督局.锅炉大气污染物排放标准:DB11/139—2015[S].北京, 2015.Beijing Municipal Environmental Protection Bureau, Beijing Municipal Bureau of Quality and Technical Supervision. Emission standard of air pollutants for boilers:DB 11/139—2015[S]. Beijing,2015.
[9]段钰锋,尹建军,冒咏秋,等.改性生物质稻杆焦脱除烟气中汞的实验研究[J].工程热物理学报, 2013, 34(3):581-585.DUAN Yufeng, YIN Jianjun, MAO Yongqiu, et al. Mercury removal from simulated flue gas by modified rice straw char[J]. Journal of Engineering Thermophysics, 2013, 34(3):581-585.
[10]王晨平,段钰锋,佘敏,等. SO2活化改性石油焦吸附剂的汞吸附特性[J].化工学报, 2017, 68(12):4764-4773.WANG Chenping, DUAN Yufeng, SHE Min, et al. Mercury adsorption characteristics of petroleum coke activated[J]. CIESC Journal, 2017, 68(12):4764-4773.
[11]佘敏,段钰锋,朱纯,等.CO2/H3PO4活化与NH4Br改性稻壳焦的脱汞性能实验研究[J].东南大学学报(自然科学版), 2014, 44(2):321-327.SHE Min, DUAN Yufeng, ZHU Chun,et al. Experimental study on mercury adsorption performances of rice husk chars activated by CO2/H3PO4and modified by NH4Br[J]. Journal of Southeast University(Natural Science Edition), 2014, 44(2):321-327.
[12]洪亚光,段钰锋,朱纯,等.硫改性椰壳活性炭管道喷射脱汞实验研究[J].东南大学学报(自然科学版), 2015, 45(3):521-525.HONG Yaguang, DUAN Yufeng, ZHU Chun, et al. Experimental study on mercury adsorption of S-impregnated coconut shell activated carbon by duct injection[J]. Journal of Southeast University(Natural Science Edition), 2015, 45(3):521-525.
[13]许静,段钰锋,姚婷,等.可再生脱汞吸附剂的研究进展[J].化工进展, 2017, 36(1):442-448.XU Jing, DUAN Yufeng, YAO Ting, et al. Research progress on regenerable mercury sorbents[J]. Chemical Industry and Engineering Progress, 2017, 36(1):442-448.
[14]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]. CIESC Journal, 2005, 56(11):2172-2177.
[15]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. Exprimental study on mercury using activated carbon injection in simulated flue gas[J]. Proceedings of the CSEE, 2013, 33(35):36-43.
[16]姚婷,洪亚光,段钰锋,等.KI改性凹凸棒管道喷射脱汞实验研究[J].中国电机工程学报, 2015, 35(22):5787-5792.YAO Ting, HONG Yaguang, DUAN Yufeng, et al. Experimental study on mercury removal by duct injection with KI-impregnated attapulgite[J]. Proceedings of the CSEE, 2015, 35(22):5787-5792.
[17]赵鹏飞,郭欣,郑楚光.载银稻壳基吸附剂的制备与表征及其脱除Hg0的实验研究[J].中国电机工程学报, 2012, 32(5):61-67.ZHAO Pengfei, GUO Xin, ZHENG Chuguang. Synthesis and characterizations of silver-loaded rice husk ash sorbents and their performance for elemental mercury removal[J]. Proceedings of the CSEE,2012,32(5):61-67.
[18] WANG Shuxiao, ZHANG Lei, WU Ye, et al. Synergistic mercury removal by convention pollutant control strategies for coal-fired power plants in China[J]. Journal of the Air&Waste Management Association, 2010, 60(6):722-730.
[19]孙巍,宴乃强,贾金平.载溴活性炭去除烟气中的单质汞[J].中国环境科学, 2006, 26(3):257-261.SUN Wei, YAN Naiqiang, JIA Jinping. Removal of elemental mercury in flue gas by brominated activated carbon[J]. China Environmental Science, 2006, 26(3):257-261.
[20] KWON S, BORGUET E, VIDIC R D. Impact of surface heterogeneity on mercury uptake by carbonaceous sorbents under UHV and atmospheric pressure[J]. Environmental Science&Technology, 2002,36(19):41624169.
[21] KRISHAN S V, GULLETT B K, JOZEWICZ W, et al. Sorption of elemental mercury by activated acrbons[J]. Environmental Science&Technology, 1994, 28(8):1506-1512.
[22] ZENG H C, JIN F, GUO J. Removal of elemental mercury from coal combustion flue gas by chloride-impregnated activated carbon[J].Fuel, 2004, 83(1):143-146.
[23]高正阳,杨维结.卤素改性活性炭氧化单质汞的机理研究[J].工程热物理学报, 2017, 38(2):381-385.GAO Zhengyang, YANG Weijie. The study of reaction mechanism of mercury oxidation on halogenated activated carbon[J]. Journal of Engineering Thermophysics, 2017, 38(2):381-385.
[24] WANG S X, ZHANG L, LI G H, et al. Mercury emission and speciation of coal-fired power plants in China[J]. Atmospheric Chemistry and Physics, 2010, 10(3):1183-1192.
[25]杜雯,殷立宝,禚玉群,等. 100MW燃煤电厂非碳基吸附剂喷射脱汞实验研究[J].化工学报, 2014, 65(11):4413-4419.DU Wen, YIN libao, ZHUO Yuqun, et al. Experimental study on mercury capture using non-carbon sorbents in 100MW coal-fired power plant[J]. CIESC Journal, 2014, 65(11):4413-4419.
[26] JONES A P, HOFFMANN J W, SMITH D N, FEELEY T J, et al. DOE/NET’s phaseⅡmercury control technology field testing program:preliminary economic analysis of activated carbon injection[J].Environmental Science&Technology, 2007, 41(4):1365-1371.