Effects of Wet Flue Gas Desulfurization and Wet Electrostatic Precipitators on Emission Characteristics of Particulate Matter and Its Ionic Compositions from Four 300 MW Level Ultralow Coal-Fired Power Plants

To achieve ultralow-emission (ULE) standards, wet electrostatic precipitators (WESP) installed downstream from wet flue gas desulfurization (WFGD) have been widely used in Chinese coal-fired power plants (CFPPs). We conducted a comprehensive field test study at four 300 MW level ULE CFPPs, to explore the impact of wet clean processing (WFGD and WESP) on emission characteristics of three size fractions of particulate matter (PM: PM2.5, PM10–2.5, and PM>10) and their ionic compositions. All these CFPPs are installed with limestone-based/magnesium-based WFGD and followed by WESP as the end control device. Our results indicate that particle size distribution, mass concentration of PM, and ionic compositions in flue gas change significantly after passing WFGD and WESP. PM mass concentrations through WFGD are significantly affected by the relative strength between desulfur slurry scouring and flue gas carrying effects. Concentrations of ions in PM increase greatly after passing WFGD; especially, SO42– in PM2.5,...