Development of a New Dry-Desulfurization Process by a Non-Thermal Plasma Hybrid Reactor

Abstract

To find out a new dry-type desulfurization process with high efficiency and cost performance, a hybrid-type reaction process combining pulsed streamer corona plasma and TiO 2 catalyst was developed in order to oxidize SO 2 to SO 3 . Experiments of both gas-phase reaction and surface reaction were performed to elucidate oxidation characteristics. Experimental results show that the oxidation fraction of SO 2 to SO 3 in the gas-phase reaction is below 5% at low temperatures (under 800 K). Similarly, when using TiO 2 only as catalyst and applying the pulsed streamer corona plasma, respectively, the oxidation fraction is not increased significantly. Moreover, when simply combining the gas-phase reaction and the surface reaction, the oxidation fraction can reach and maintain only about 10% below 673 K. Contrary to the above two results, the oxidation fraction could be increased significantly by adding H 2 O of about 0.2 vol %. Hydrogen peroxide was demonstrated to have better oxidation promotion characteristics in comparison to the addition of H 2 O and H 2 O + plasma. The oxidation fractions of 60% and 90% can be achieved, respectively, by adding a very small amount of H 2 O 2 and applying the pulsed streamer corona plasma in the reaction process. Finally, these experimental results confirmed our initial hypothesis that hydroxyl radicals (OH) enhance the oxidation of SO 2 to SO 3 in both the gas-phase reaction and the surface reaction on TiO 2 .