Experimental study on the influence of H 2 O vapor and O 2 for desulfurization and denitrification of the diesel exhaust in marine application by non‐thermal plasma

Abstract

To improve the pollutant removal efficiency by non-thermal plasma (NTP), the effect of H2O vapor and O2 on removal efficiency of NO and SO2 as well as the reduction of CO was investigated in H2O/O2/SO2/NO/C3H6/CO2/N2 system. To analyse the reaction mechanism, the effects of H2O vapor and O2 on the emission intensity of O ( 3 p 5 P → 3 s 5 S 2 0 ) and O H ( A 2 ∑ + → X 2 ∏ ) were investigated. The experimental results show that the increase of H2O vapour (0%–9.8%) promotes the generation of OH radicals, increases the removal efficiency of NO from 18.9% to 57.3%, decreases the energy per NO removed from 449.0 to 148.1 eV/NO, increases SO2 removal efficiency from 4.8% to 35.3%, decreases the energy per SO2 removed decreases from 2784.0 to 582.9 eV/SO2, and reduces the generation of CO from 460 to 229 ppm. In the range of 0%–15%, the increase of O2 content promotes the formation of O radicals, increases the removal efficiency of NO from 8.5% to 54.2%, and decreases the energy per NO removed from 994.3 to 156.4 eV/NO. In the range of 0%–5%, increasing O2 content promotes SO2 removal efficiency from 8.7% to 24.8%, and decreases the energy per SO2 removed from 2485.7 to 876.6 eV/SO2. However, CO generation increases from 200 to 350 ppm with the increase of O2 in 0%–5% due to the incomplete oxidation of C3H6. In the range of 5%–15%, the increase of O2 produces more O radicals, decreases the removal efficiency of SO2 from 24.8% to 23.5% and the generates of CO from 350 to 311 ppm. This study is helpful for improving the efficiency of NTP for desulfurization and denitrification, while reducing the by-product CO.