Effects of CH₄ and CO on the Reduction of Nitric Oxide to Nitrogen in a Discharge Reactor

Abstract

Additives are often added to enhance the efficiency of NO removal. This study uses a radio frequency (rf) discharge to consider the effect of added CH 4 and CO to simulated NO/N 2 /O 2 /H 2 O mixtures on the elevation of NO conversion and the reduction of NO into N 2 . The enhancement levels of NO conversion when using various additives were found to be in this order: ϩCH 4 Ͼ ϩCO Ͼ no additive. NO conversion reached 99.3%, 86.2%, and 77.6% when adding CH 4 , CO, and without additive, respectively, at inlet additive/NO molar ratio (R) ϭ 5 and at 120 W. Moreover, the fraction of total N atoms converted from NO into N 2 (F N2 ) was very high, reaching 99.4% and 99.5% when adding CH 4 and CO, respectively, at R ϭ 1 and at 120 W. The better operating conditions are using CH 4 as the additive at R Ն 1 and a power of Ͼ60 W to reach a higher NO conversion with a higher F N2 . However, it should be noted that this rf plasma approach is not practical at this stage because of its relative low pressure.