Kinetic Modeling of the Gas-Phase Oxidation of Nitric Oxide Using Hydrogen Peroxide

The use of hydrogen peroxide (H2O2) to enhance the oxidation of nitric oxide (NO) under postflame conditions in the presence or absence of sulfur dioxide (SO2) has been studied by means of chemical kinetic modeling and compared with pilot-scale experimental data. The experimental results were obtained from a nonisothermal reactor at atmospheric pressure with inlet temperatures in the range of 770-790  K. The CHEMKIN-II model with a kinetic mechanism from the literature was employed for this work. At the temperatures studied, H2O2 produces OH and HO2 radicals which enhance the oxidation of NO. The OH radical also helps oxidize SO2. The modeling results confirmed an optimum temperature of about 775  K where the NO conversion reached about 90% with an H2O2:NO molar ratio of 1:1. Conversion of NO2 to HNO3 was found to occur to a slight extent. Finally, the presence of SO2 was found to promote slightly the oxidation of NO to NO2.