Influences of water vapor and fly ash addition on NO and SO2 gas conversion efficiencies enhanced by pulsed corona discharge

The NO and SO2 gas conversion processes in a pulsed corona discharge field have been studied. The experiments were conducted to investigate the influences of water vapor and fly ash addition on the conversion efficiencies of NO and SO2. Experimental results show that positive pulsed corona discharge can facilitate NO and SO2 conversion processes, and the conversion efficiencies of NO and SO2 are primarily dependent on the radicals OH, O and the active species O3, HO2, H2O2, etc. With water vapor addition, SO2 conversion efficiency is improved, but NO conversion process is restrained. Low fly ash concentration helps to enhance the conversion of NO and SO2; however, the conversion efficiencies of NO and SO2 are drastically degraded by high fly ash concentration addition. The synergistic effects of water vapor and fly ash addition strengthen the chemical adsorption ability of the fly ash surface, which results in a considerable improvement in the conversion of NO and SO2. Furthermore, the specific input energy plays an important role in NO and SO2 conversion efficiencies. Measured conversion efficiencies of NO and SO2 reach about 60% and 90%, respectively, under the conditions tested.