Plasma-assisted process for removing NO/NO_x from gas streams with C₂H₄ as additive

NO_x removal from gas streams via dielectric barrier discharges (DBDs) has been experimentally evaluated. This paper investigates the effect of injecting C₂H₄ as an additive with respect to the De-NO_x chemistry and the effect of gas composition on NO/NO_x removal efficiencies. Experimental results indicate that both removal efficiencies of NO and NO_x are enhanced with increasing applied voltage, gas temperature, and water vapor. Water vapor in gas streams has a distinct influence on NO_x removal by generating OH radicals to convert NO₂ to form HNO₃. NO_x removal decreases with increasing oxygen content although NO removal increases with increasing oxygen content. As high as 100% of NO and 57% of NO_x are removed at 140°C for the gas stream containing [NO]:[C₂H₄]:[H₂O_(g):]: [O₂]:[N₂]=0.05:0.2:3.0:5.0:91.75. Major mechanisms for NO and NO_x removals in DBD processingwith C₂H₄ as an additive are described in the text.