Effect of flue gas pollution control devices on mercury emission from coal-fired power plants

Coal-fired power plant is one of the largest sources of mercury emitted into the atmosphere artificially. In the paper, more intensive investigations were performed in 27 power plants for observing distribution of mercury at all the effluents. Mass balance of mercury was figured out from the emission data and analysis results of mercury at all the in- and out-streams. The results show that, concentrations of mercury emitted from stack gas equipped with air pollution control devices (APCDs) range between 0.6734 and 14.4312 mu g/m(3) with coal mercury content lower than 0.20mg/kg. FGD gypsum mercury is about 2 similar to 10 times as that of in coal. The average mercury removal efficiency by ESP is only about 29.36% while ESP +wFGD and dry-FGD+FF about 68.72% and 81.51% separately. Therefore, it is necessary to enhance the existing APCDs, wash and mix coal to Hg co-removal for coal-fired power plants.