Mercury Removal Characteristics of Coal-Fired Power Plants

Abstract

The standard Ontario Hydro Method (OHM) was used into the flue gas mercury sampling before and after fabric filter (FF)/ electrostatic precipitator (ESP) locations in coal-fired power stations in China, and then various mercury speciation, Hg 0 , Hg 2+ and Hg P in flue gas, were analyzed by using EPA method. The solid sample, such as coal, bottom ash and ESP ash, were analyzed by DMA 80, based on EPA Method 7473. According to mercury balance, mercury speciation and its distribution in different locations downstream the flue gas were obtained. The mercury removal efficiency of coal-fired power plants installed FF is more than 20% and 80% respectively. While the mercury removal efficiency of coal-fired power plants installed ESP is around 7%, 20% and 4% respectively. The concentrations of chlorine and sulfur in coal, NO x , SO 2 , HCl and Cl 2 in flue gas have positive correlation with formation of the oxidized mercury.