Abstract: The effect of mercury removal in the existing air pollutant control devices in coal-fired power plants is evaluated and the mercury control technologies, which could be classified as pre-combustion control and flue gas mercury removal technology and mercury removal related multi-pollutant removal technologies are presented. According to the data collected, the SCR system can convert Hg⁰ to Hg²⁺, which could be removed more easily by downstream equipment. Both the electrostatic precipitator (ESP) and the fabric filter can remove Hgp and Hg²⁺ from the flue gas, while the latter shows better performance. The carbon content of the flue gas has great effect on the removal efficiency of dust collectors, that is, more carbon content leads to better efficiency. The existing flue gas desulphurization (FGD) systems can collect Hg²⁺, but can also convert Hg²⁺ to Hg⁰. The method of adding bromides to coal can raise the Hg²⁺ content of flue gas, which could enhance the performance of mercury removal for the existing air pollutant control devices. Some multi-pollutant control technologies with promising prospect are also introduced, which could achieve the goal of removing SO_x, NO_x, Hg and fine particulate matter.

Key words: flue gas mercury removal, mercury content of coal, existing environmental equipment mercury removal, multi-pollutant