Abstract:A full-scale field study of lead (Pb) emission from coal combustion was conducted at six coal-fired power plants in China. Flue gas samples were taken from the inlets and outlets of the existing air pollutant control devices (APCDs) to investigate their effects on speciation and distribution of Pb in the flue gas. Concurrent with flue gas sampling, coal, bottom ash, fly ash and samples from the FGD process (desulfurization gypsum and waster water) were collected. Average release of Pb from the pulverized-coal (PC) boilers was 97.11% of Pb in feed coal. In comparison, the release of Pb from a fluidized bed furnace was lower, at 84.99%. A high proportion of Pb (86%~92%) was found as particulate-bound Pb (Pbp) in the flue gas at outlet of boiler. Further, there was a positive correlation between the proportion of particulate-bound Pb (Pbp) and the chlorine content in the coal. The existing APCDs were able to remove most of the Pb in the flue gas, dedusting devices being most effective. Around 91.85% of Pb in flue gas was removed by electrostatic precipitator (ESP), while Bag-house filters captured 95.12%. The Pb removal efficiency of wet flue gas desulfurization (FGD) varied from 35.67 to 77.81%, which depended on the process operation. The result of overall lead (Pb) balance showed that 81.97%~90.18% of Pb in feed-coals was discharged with fly ash, while 3.94%~11.82% of Pb was discharged with the desulfurization gypsum. Only 1.75%~5.40% was emitted directly into the atmosphere.
邓双, 张凡, 刘宇, 石应杰, 王红梅, 张辰, 王相凤, 曹晴. 燃煤电厂铅的迁移转化研究[J]. 中国环境科学, 2013, 33(7): 1199-1206.
DENG Shuang, ZHANG Fan, LIU Yu, SHI Ying-Jie, WANG Hong-Mei, ZHANG Chen, WANG Xiang-Feng, CAO Qing. Lead emission and speciation of coal-fired power plants in China. CHINA ENVIRONMENTAL SCIENCECE, 2013, 33(7): 1199-1206.