Simultaneous Removal of H2S and Dust in the Tail Gas by DC Corona Plasma

Abstract

The removal of hydrogen sulfide and dust simultaneously by the DC corona discharge plasma with a wire-cylinder reactor was studied at atmospheric pressure and room temperature. The outlet gases were analyzed by Fourier Transform Infrared. Chemical compositions of the dust collected from ground electrode were analyzed by X-ray fluorescence. The results showed that the DC corona discharge is effective in removing H2S and dust simultaneously. The best H2S conversion was gained with the 2 cm discharge gap. The lower inlet H2S concentration, the higher conversion efficiency was gained at any specific input energy (SIE), while the energy yield was on the contrary. The removal efficiency of H2S decreased gradually as oxygen concentration increased, which means that the H2S decomposition mainly depends on direct electron collisions or short-living species, such as·O, ·OH radicals in the non-thermal plasma. At the initial stage, the conversion efficiency of H2S increased with the increasing of relative humidity, but later decreased while the relative humidity keep increasing with the same SIE. Existing of dust can not only reduce the energy consumption of H2S conversion and improve the removal efficiency, but also inhibit the yield of SO2 for it can further react with some compounds in the dust. With the discharge gap of 2 cm, inlet H2S concentration of 2400 ppm, O2 Of 0.5 %, relative humidity of 41 %, dust content of 4000 ± 5 % mg/m3 and SIE of 600 J/L, the H2S conversion reached 98.8 %, and the dust removal efficiency was close to 100 %.