Effect of CO2 on Nonthermal-Plasma Reactions of Nitrogen Oxides in N2. 1. PPM-Level Concentrations

PPM-level concentrations of CO2 are added to NO/N2 mixtures to determine the effect of CO2 on plasma generation and to investigate the mechanism of CO2 reactions. Addition of 599.9 ppm CO2 does not affect the electric discharge in NOx in N2 nonthermal plasma. However, CO2 slightly dissociates, with CO2 conversion reaching a maximum of about 5.5% at the power input at which NO conversion ceases. NO(A), the first-excited electronic state of NO, is detected by corona-induced optical emission and is found to contribute to CO2 dissociation. A kinetic model including 38 reactions is required to adequately model decomposition of NOx and CO2 in the presence of CO2. About 18% of the NO(A) that is formed reacts with CO2 to form NO, CO, and O.