Simultaneous oxidation of NO, SO2 and Hg-0 from flue gas by pulsed corona discharge

A process capable of simultaneously oxidizing NO, SO2, and Hg-0 was proposed, using a high-voltage and short-duration positive pulsed corona discharge. By focusing on NO, SO2, and Hg-0 oxidation efficiencies, the influences of pulse peak voltage, pulse frequency, initial concentration, electrode number, residence time and water vapor addition were investigated. The results indicate that NO, SO2 and Hg-0 oxidation efficiencies depend primarily on the radicals (OH, HO2, O) and the active species (O-3, H2O2, etc.) produced by the pulsed corona discharge. The NO, SO2 and Hg-0 oxidation efficiencies could be improved as pulse peak voltage, pulse frequency, electrode number and residence time increased, but they were reduced with increasing initial concentrations. By adding water vapor, the SO2 oxidation efficiency was improved remarkably, while the NO oxidation efficiency decreased slightly. In our experiments, the simultaneous NO, SO2, and Hg-0 oxidation efficiencies reached to 40%, 98%, and 55% with the initial concentrations 479 mg/m(3), 1040 mg/m(3), and 15.0 mu g/m(3), respectively.