Influence of flue gas cleaning system on characteristics of PM2.5 emission from coal-fired power plants

This study investigated the influence of precipitators and wet flue gas desulfurization equipment on characteristics of PM2.5 emission from coal-fired power stations. We measured size distribution and removal efficiencies, including hybrid electrostatic precipitator/bag filters (ESP/BAGs) which have rarely been studied. A bimodal distribution of particle concentrations was observed at the inlet of each precipitator. After the precipitators, particle concentrations were significantly reduced. Although a bimodal distribution was still observed, all peak positions shifted to the smaller end. The removal efficiencies of hybrid ESP/BAGs reached 99 % for PM2.5, which is considerably higher than those for other types of precipitators. In particular, the influence of hybrid ESP/BAG operating conditions on the performance of dust removal was explored. The efficiency of hybrid ESP/BAGs decreased by 1.9 % when the first electrostatic field was shut down. The concentrations and distributions of particulate matter were also measured in three coal-fired power plants before and after desulfurization devices. The results showed diverse removal efficiencies for different desulfurization towers. The reason for the difference requires further research. We estimated the influence of removal technology for particulate matter on total emissions in China. Substituting ESPs with hybrid ESP/BAGs could reduce the total emissions to 104.3 thousand tons, with 47.48 thousand tons of PM2.5. © 2014, The Author(s).