摘要
Effects of C3H6 and CO2 on desulfurization and denitrification by nonthermal plasma (NTP) and formation of the by-product CO were investigated under the simulated diesel exhaust condition. Optical emission spectroscopy (OES) was employed to observe the plasma process, and effects of C3H6 and CO2 on the emission intensities of O(3p(5)P -> 3s(5)S(2)(0)) and OH (A(2)sigma(+)-> X-2 pi)were detected. The experimental result shows that the CO2 concentration has negligible effect on formation of O and OH radicals, and the change in the CO2 concentration has no significant impact on the removal of NO and SO2, but every 1% increase of the CO2 concentration will raise the CO by about 22.5 ppm. When the C3H6 concentration increases from 0 to 600 ppm, the NO removal efficiency increases from 42.8 to 70.5%. However, the existence of C3H6 has marginal effect on the SO2 removal. C3H6 is an effective additive for the oxidative removal of NO, which can react with O and OH radicals in DBD reactor and generate a lot of oxidative radicals including HO2 and RO2 (C2H5O2, CH3O2, HOC3H6O2). The generated HO2 and RO2 will replace O and OH radicals as the main species to realize the oxidative removal of NO. However, the by-product CO formed in the plasma process and the unreacted C3H6 also need to be concerned. Through analyzing the mechanism of CO2 and C3H6 promoting the removal of NO and SO2 in a more realistic simulated gas atmosphere based on OES, the present study can provide guidance for improving the efficiencies of desulfurization and denitrification for marine diesel exhaust by NTP.
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单位武汉理工大学