PM2.5 Emission Reduction by Technical Improvement in a Typical Coal-Fired Power Plant in China

ABSTRACT

To investigate PM_2.5 reduction by technical improvement in typical Chinese coal-fired power plants, two units built in different time with different particulate matter (PM) control technologies but with the same coal-fired boiler type were selected to characterize the concentrations of PM_2.5 generated and emitted from coal-fired power plants. We found that significant benefit of PM_2.5 emission reduction was achieved by technological improvement. Due to the increase in the installed capacity and the application of low NO_x burner alone, PM_2.5 emission factor without adopting other air pollution control devices decreased from 0.153 kg t^–1 (the 100 MW unit) to 0.123 kg t^–1 (the 300 MW unit). With the help of an improved electrostatic precipitator (ESP) of which removal efficiency increased from 76.4% to 97.5%, PM_2.5 emission factor further decreased from 0.014 kg t^–1 (the unit with a normal ESP) to 0.003 kg t^–1 (the unit with a cold-side ESP and a wet flue gas desulphurization (WFGD)). However, the application of flue gas denitrification and desulfurization devices may alter PM_2.5 compositions and their emissions. For instance, the installation of a WFGD was found to largely increase the emissions of water-soluble ions in PM_2.5 (e.g., SO₄^2–, Ca²⁺, and NH₄⁺).