Removal characteristics of particulate matters and hazardous trace elements in a 660 MW ultra-low emission coal-fired power plant

Abstract

Coal is the dominant energy source in China, and coal-fired power plant (CFPP) accounts for about half of coal consumption. However, air pollutant emissions from coal-fired power plants cause severe environmental and ecological problems. The most stringent regulations to limit air pollutant emissions from CFPP have been implemented in China since 2015. The ultra-low emission standards require that particulate matters (PMs) concentration from stack must not exceed 5 mg/Nm3. For exploring the emission characteristics of particulate matters and some trace elements, the field sampling test was carried out in a 660 MW ultra-low emission coal-fired power plant. It is equipped with low temperature economizer (LTE), electrostatic precipitators (ESP), wet flue gas desulfurization (WFGD), and wet electrostatic precipitator (WESP). The results showed that the mass removal efficiency of PM10 is about 80% in ESP and about 70% in WESP, in which most of them are PM2.5. The mass concentration removal efficiency of PM10 was 98.77% in ESP while that of PM2.5 is 98.58%. The mass concentration removal efficiency of PM10 was 63.43% in WESP while that of PM2.5 is 71.92%. At the same time, the trace elements on different particle sizes were analyzed. Manganese contents were found to be independent of the particle size. Cr, As and Pb are mainly enriched in the fine ash particles. In terms of the emission factors, Cr, As, Pb, and Mn are mainly in the fine particles.