Oxidization of SO2 by Reactive Oxygen Species for Flue Gas Desulfurization and H2SO4 Production

A strong ionization dielectric barrier discharge was used to produce a high concentration of reactive oxygen species that were then injected into a simulated flue gas in a duct to remove SO2 by oxidation. Sulfuric acid (H2SO4) was produced through the following two reactions: (1) O3 oxidation of SO2–SO3, which then reacted with H2O to produce H2SO4; and (2) reaction of O2+ with H2O to produce ·OH radicals, which then rapidly and non-selectively oxidized SO2–H2SO4. When the molar ratio of reactive oxygen species to SO2 was 4:1, the SO2 removal efficiency was 94.6%, the energy consumption per cubic meter of flue gas was 13.3 Wh/m3, the concentration of recovered H2SO4 was 4.53 g/l, and the H2SO4 recovery efficiency was 28.8%. The H2O volume fraction in the simulated flue gas affected the SO2 removal efficiency, whereas the O2 and CO2 volume fractions did not. These results prove that oxidation by reactive oxygen species is a feasible method for flue gas desulfurization.