Simultaneous Removal of COS, H2S, and Dust in Industrial Exhaust Gas by DC Corona Discharge Plasma

Simultaneous removal of COS, H2S, and dust by means of DC corona discharge plasma was investigated in a plasma reactor. The results showed that the DC corona discharge was effective in removing COS, H2S, and dust simultaneously. As the content of O2 increased, the conversion of COS and H2S decreased. O3 was produced at high O2 content, resulting in more energy being shared. Higher temperature is not conducive to the conversion of COS and H2S. Dust could react with gaseous pollutant or serve as a carrier under the electric field. The conversion of COS and H2S and yield of CO2 were slightly improved after the dust was introduced. In contrast, a significant decrease of the yield of SO2 and CO was observed. Meanwhile, the removal efficiency of dust reached 99%. In a plasma reactor, the chemical bonds of COS and H2S were broken and then further oxidized to sulfur-containing and carbon-containing products caused by free electrons, oxygen radicals, and ozone. The CO and CO2 products were generated from the COS, and sulfur compounds (S, SO2, and SO42–) were a result of the oxidation of COS and H2S. Free electrons and oxidative radicals might play more significant roles in the conversion of COS and H2S.