Characteristics of Mercury Emissions from a Coal-fired Power Plant

Abstract

Coal-fired power plant is one of the important mercury emission sources in the world. In order to understand the characteristics of mercury emission from the coalfired power plants in Shanghai area, a series of measurement data was collected on a continuous basis to evaluate the mercury emissions speciation profiles, and the mercury emissions factors as well. The whole-process mercury emissions data in 2012 was also obtained with the manual sampling method. The results show that (1) the ratio of the mercury balances in the two units were 75.6% and 87.8%, respectively; (2) the existing air pollutant control devices in the two power plants showed certain mercury removal capability, and the average mercury removal efficiencies from dust collector plus Wet-FGD was more than 50%; (3) the average mercury content in the mixed coal 73 µg/kg, which ranged from 40 to 102 µg/kg. The annual average emission concentration of Hg 2+ in #1 Unit was close to that in #4 Unit. However, the emission concentration of Hg 0 in #4 Unit was 2.62 µg/Nm 3 , two times higher than that in #1 Unit. The Hg 0 was removed by the Fabric Filter, whose efficiency was two times more than the ESPs. (4) In the coal-fired power plants, the mercury emission was greatly impacted by coal types, APCD.