Removal of NO and SO2 by pulsed corona discharge process

Abstract

Overall examination was made on the removal of NO and SO2, by pulsed corona discharge process. The mechanism for the removal of NO was found to largely depend on the gas composition. In the absence of oxygen, most of the NO removed was reduced to N2; on the other hand, oxidation of NO to NO2 was dominant in the presence of oxygen even when the content was low. Water vapor was an important ingredient for the oxidation of NO2, to nitric acid rather than that of NO to NO2. The removal of NO only slightly increased with the concentration of ammonia while the effect of ammonia on the removal of SO2 was very significant. The energy density (power delivered/feed gas flow rate) can be a measure for the degree of removal of NO. Regardless of the applied voltage and the flow rate of the feed gas stream, the amount of NO removed was identical at the same energy density. The production of N2O increased with the pulse repetition rate, and the presence of NH3 and SO2 enhanced it. Byproducts generated from propene used as additive were identified and analyzed. The main byproducts other than carbon oxides were found to be ethane and formaldehyde, but their concentrations were negligibly small.