Combined plasma-catalytic processing of nitrous oxide

The gliding arc discharge, combined with a catalytic bed, has been applied for nitrous oxide processing in oxygen containing gases. It has been found that under conditions of the gliding arc, nitrous oxide in mixtures with oxygen or air not only decomposes to oxygen and nitrogen, but is also oxidised to nitric oxide. The overall conversion of nitrous oxide, as well as the degree of N2O oxidation to NO were studied as a function of its initial concentration, flow rate, and discharge power. The overall N2O conversion and degree of oxidation to NO decreased with increasing flow rate and initial N2O concentration, and increased with increasing discharge power. The degree of N2O oxidation to NO varied within 20–37%. The overall conversion and degree of N2O oxidation increased when granular dielectric materials (TiO2, SiO2 (quartz glass), and γ-Al2O3) were introduced into the reaction zone. The energy efficiency and the overall conversion of N2O were still further increased due to catalytic effects of a number of metal oxides (CuO, NiO, MnO2, Fe2O3, Co3O4, ZrO2) deposited on γ-Al2O3. The activity of the oxide catalysts within the active power range of 300–360 W decreased in the order: CuO>Fe2O3>NiO>MnO2>Co3O4>ZrO2. It has been concluded that the combined plasma-catalytic processing may be an efficient way for the reduction of N2O emissions.