Mercury emission from three lignite-fired power plants in the Czech Republic

Abstract

The main aim of the research was to estimate mercury emissions from three selected power plants in the Czech Republic, where lignite is burnt, as well as to conduct a comprehensive measurement of Hg in fuels, fly ash and desulfurization products. The average concentrations of the mercury in fuel were as follows: for Power Plant 1 it was 0.19 ± 0.01 mg/kg, in the case of power plants 2 and 3 it was 0.24 ± 0.03 mg/kg and 0.23 ± 0.02 mg/kg, respectively. The average concentrations of mercury in the flue gas, at the stack, were the following: for Power Plant 1–19.5 ± 2.9 μg/m3N, for Power Plant 1–19.9 ± 3.0 μg/m3N and for power plant 3–23.5 ± 3.5 μg/m3N. In all three cases, the mercury emission level exceeds the planned permissible emission level, 7 μg/m3N. The percentage of the mercury removed by means of the flue gas purification systems installed in the power plants varied from approximately 30 to 53%. The efficiency of mercury removal with the fly ash in the electrostatic precipitators ranged from 2 to 52%. The efficiency of mercury removal in the SO2 removal systems ranged from about 1 to 30%.