Effects of ultra-low emission air pollution control devices on the evolution of PM and its associated water-soluble ions in a 1000 MW coal-fired power plant

Abstract

PM (Particulate matter) is a major air pollutant from CFPPs (coal-fired power plants). APCDs (Air pollutant control devices) work in concert to achieve ultra-low emission requirements. Large-scale and higher parameters CFPPs have become a future trend. This work investigated the PM evolution of the APCDs in a 1000 MW ultra-low emission CFPP. The PM1, PM2.5, and PM10 (particulate matter with an aerodynamic diameter less than 1, 2.5, and 10 μm) and WSIs (water-soluble ions) characteristics at the inlet and outlet of selective catalytic reduction (SCR), low-low temperature electrostatic precipitators (LLT-ESP), wet flue gas desulfurization (WFGD), and wet electrostatic precipitator (WESP) were investigated. PM samples were collected by a Dekati low-pressure impactor. The WSIs in PM (K+, Ca2+, Na+, Mg2+, NH4+, Cl-, SO42-, NO3–) were also detected by inductively coupled plasma optical emission spectrometer, ion chromatography, and ultraviolet spectrophotometer, respectively. The results show that PM1, PM2.5, and PM10 generally decrease along with flue gas steam, while PM1 increases by 16.36% and 17.47% at SCR outlet and GGH outlet. The percentages of WSIs in PM show an increasing trend along with flue gas steam. SO42- and Ca2+ are the main components of WSIs. ESP had high efficiencies of 98.18%, 98.54%, and 99.31% for PM1, PM2.5, and PM10, respectively. PM reduces by more than 50% after WFGD and WESP. About 1.00% of PM1, 0.29% of PM2.5, and 0.08% of PM10 are emitted at Stack. PM emissions meet ultra-low emission requirements. The emission factors of PM1, PM2.5, and PM10 are 8.73, 15.90, and 21.04 g/t_fuel on average.