Comparative Study on the Characteristics of Mercury Emission from Coal-Fired Plants before and after Ultra-Low Emission Retrofitting

doi:10.11930/j.issn.1004-9649.202006328

Abstract

Abstract: In this paper, with the aid of Ontario Hydro Method (OHM), the mercury emissions from the two units with ultra-low emission retrofit are sampled and tested, then the testing data are compared and analyzed with those before the retrofitting. The testing results show that the mercury emission concentrations from the two units are 2.31 and 4.22 μg/m³ respectively, far below the limit value in the current domestic national standard. The mercury emission factors are reduced from 1.76 and 3.13 g/TJ to 0.83 and 2.17 g/TJ correspondingly, 52.84% and 30.67% of decrease. And the total mercury removal efficiencies of the retrofitted air pollution control devices with the combination of SCR+DESP+WFGD+WESP are 87.91% and 82.27%, respectively, 18.34% and 16.66% of increase compared with the efficiency of 69.57% and 65.61% of the combination of SCR+DESP+WFGD before the retrofit. These data indicate that the ultra-low emission retrofit has improved the oxidation rate of SCR to elemental mercury, and enhanced the capability of WFGD to capture mercury oxide and particulate mercury. Besides, the newly added WESP also displays a synergistic removal capability of both mercury oxide and elemental mercury. Furthermore, by improving the uniformity of SCR flow field, strengthening the maintenance of catalyst and inhibiting the reduction of mercury oxide in WFGD, the synergistic mercury removal capacity can be effectively guaranteed for the present air pollution control devices.

Key words: coal-fired plant, ultra-low emission retrofitting, air pollution control devices (APCDs), mercury synergistic removal, mercury emission factor

WANG Hongliang, XU Yueyang, XUE Jianming, LIU Tao, GUAN Yiming. Comparative Study on the Characteristics of Mercury Emission from Coal-Fired Plants before and after Ultra-Low Emission Retrofitting[J]. Electric Power, 2020, 53(11): 243-251.

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URL: https://www.electricpower.com.cn/EN/10.11930/j.issn.1004-9649.202006328

https://www.electricpower.com.cn/EN/Y2020/V53/I11/243

References

[1] ZHANG L, ZHUO Y Q, CHEN L, et al. Mercury emissions from six coal-fired power plants in China[J]. Fuel Processing Technology, 2008, 89(11): 1033-1040.
[2] 张凡, 邓双, 刘宇, 等. 燃煤电厂大气汞等污染物的排放与控制[M]. 北京: 中国环境出版社, 2015.
[3] 中国电力企业联合会. 2020年中国电力行业年度发展报告[R]. 北京: 中国建材工业出版社, 2020.
[4] ZHANG Y, YANG J P, YU X H, et al. Migration and emission characteristics of Hg in coal-fired power plant of China with ultra low emission air pollution control devices[J]. Fuel Processing Technology, 2017, 158: 272-280.
[5] 郭静娟, 刘松涛, 张优, 等. 基于燃煤电厂超低排放的汞分布特性研究[J]. 中国环境监测, 2020, 36(1): 55-59
GUO Jingjuan, LIU Songtao, ZHANG You, et al. Impacts of ultra-low emission in coal-fired power plants on the distribution characteristics of mercury[J]. Environmental Monitoring in China, 2020, 36(1): 55-59
[6] 华晓宇, 章良利, 宋玉彩, 等. 燃煤机组超低排放改造对汞排放的影响[J]. 热能动力工程, 2016, 31(7): 110-116
HUA Xiaoyu, ZHANG Liangli, SONG Yucai, et al. Influence of the ultra low emission modification of a coal-fired unit on the mercury emissions[J]. Journal of Engineering for Thermal Energy and Power, 2016, 31(7): 110-116
[7] 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
[8] 魏绍青, 滕阳, 李晓航, 等. 300 MW等级燃煤机组煤粉炉与循环流化床锅炉汞排放特性比较[J]. 燃料化学学报, 2017, 45(8): 1009-1016
WEI Shaoqing, TENG Yang, LI Xiaohang, et al. Comparison of mercury emission from around 300 MW coal-fired power generation units between pulverized boiler and circulating fluidized-bed boiler[J]. Journal of Fuel Chemistry and Technology, 2017, 45(8): 1009-1016
[9] 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
[10] 赵毅, 韩立鹏. 660 MW超低排放燃煤电站汞分布特征研究[J]. 环境科学学报, 2019, 39(3): 853-858
ZHAO Yi, HAN Lipeng. Distribution characteristics of mercury in 660 MW coal-fired power plant with ultra-low emission[J]. Acta Scientiae Circumstantiae, 2019, 39(3): 853-858
[11] 陈磊, 段钰锋, 赵士林, 等. 350 MW超低排放燃煤电厂污染物控制装置对汞的协同脱除[J]. 热能动力工程, 2020, 35(2): 187-193, 200
CHEN Lei, DUAN Yufeng, ZHAO Shilin, et al. Mercury co-removal by the air pollutant control devices in a 350 MW ultra-low emission coal-fired power plant[J]. Journal of Engineering for Thermal Energy and Power, 2020, 35(2): 187-193, 200
[12] 王建庆. 煤中汞在空气重介质流化床分选过程中的分配规律[D]. 徐州: 中国矿业大学, 2015.
WANG Jianqing. The distribution rule of mercury in coal during the separation process of air dense medium fluidized bed[D]. Xuzhou: China University of Mining and Technology, 2015.
[13] LUTTRELL G H, KOHMUENCH J N, YOON R H. An evaluation of coal preparation technologies for controlling trace element emissions[J]. Fuel Processing Technology, 2000, 65/66: 407-422.
[14] 冯立品. 煤中汞的赋存状态和选煤过程中的迁移规律研究[D]. 北京: 中国矿业大学, 2009.
FENG Lipin. The study of mercury occurrence in coal and migration regularity during coal preparation[D]. Beijing: China University of Mining and Technology, 2009.
[15] 吴清茹, 赵子鹰, 杨帆, 等. 中国燃煤电厂履行《关于汞的水俣公约》的差距与展望[J]. 中国人口·资源与环境, 2019, 29(10): 52-60
WU Qingru, ZHAO Ziying, YANG Fan, et al. Gaps and prospects for the implementation of Minamata Convention on Mercury by China's coal-fired power plants[J]. China Population Resources and Environment, 2019, 29(10): 52-60
[16] ZHAO S L, DUAN Y F, YAO T, et al. Study on the mercury emission and transformation in an ultra-low emission coal-fired power plant[J]. Fuel, 2017, 199: 653-661.
[17] ZHAO S L, PUDASAINEE D, DUAN Y F, et al. A review on mercury in coal combustion process: content and occurrence forms in coal, transformation, sampling methods, emission and control technologies[J]. Progress in Energy and Combustion Science, 2019, 73: 26-64.
[18] REYNOLDS J. Multi-pollutant control using membrane-based up-flow wet electrostatic precipitation[R]. Office of Scientific and Technical Information (OSTI), Ohio University, Akron, Ohio, 2004.
[19] 睢辉, 张梦泽, 董勇, 等. 燃煤烟气中单质汞吸附与氧化机理研究进展[J]. 化工进展, 2014, 33(6): 1582-1588, 1595
SUI Hui, ZHANG Mengze, DONG Yong, et al. Research progress of adsorption and oxidation mechanism of elemental mercury from coal-fired flue gas[J]. Chemical Industry and Engineering Progress, 2014, 33(6): 1582-1588, 1595
[20] 赵毅, 韩立鹏. 超低排放燃煤电厂低低温电除尘器协同脱汞研究[J]. 动力工程学报, 2019, 39(4): 319-323, 330
ZHAO Yi, HAN Lipeng. Synergistic removal of mercury by low-low temperature ESP for ultra-low emission coal-fired power plants[J]. Journal of Chinese Society of Power Engineering, 2019, 39(4): 319-323, 330