[Removal of NO and Hg0 in flue gas using alkaline absorption enhanced by non-thermal plasma].

ABSTRACT

Non-thermal plasma (NTP) induced by positive corona discharge was utilized to oxidize NO and Hg0 to more water-soluble NO2 and Hg2+ under the conditions of simulated flue gas. The effects of discharge voltage and inlet SO2 and NO concentrations on NO and Hg0 oxidation and their removals by alkaline absorption were investigated. The results show that the oxidation and removal of NO and Hg0 are enhanced with the increase of discharge voltage. The concentrations of NO and NO2 at the outlet of absorption tower are 0 and 69 mg/m3 with an inlet NO concentration of 134 mg/m3 and a discharge voltage of 12. 8 kV while the outlet concentrations of Hg0 and Hg2+ are 22 microg/m3 and 11 microg/m3 with an inlet Hg0 concentration of 110 microg/m3 and a discharge voltage of 13.1 kV. The presence of SO2 slightly improves the oxidation and removal of Hg0 while it has almost no effect on NO oxidation and its removal. The oxidation and removal of Hg0 are significantly inhibited with the increase of inlet NO concentration. In the coexistence of 800 mg/m3 SO2, 134 mg/m3 NO and 110 microg/m3 Hg0, the removal efficiencies are 57% for NO and 31% for Hg0 with an energy input of 77 J/L.