Energy conversion and temperature dependence in ozone generator fed by synthetic air

Abstract

ABSTRACTA homogenous chemical kinetic model consisting of 21 species and 118 reactions is applied to investigate energy conversion and its temperature dependence in ozone generator fed by synthetic air. The portion of electric energy converted into reaction heat, gas heating and heat loss to surroundings (by convection) in terms of the total electric energy input, the conversion ratios ηreaction, ηgas, and ηloss, are obtained. The detailed reaction pathway including the degree of transformation among species for ozone production is also obtained via simulation of the reaction kinetics. In addition, sensitivity analysis and rate-of-production analysis for the three foremost species O3, O, and N2(A) are performed to understand quantitatively the temperature dependence of sensitivity coefficient and production rate for each individual reaction. ηreaction shows a steep rise at low specific energy, but then suffers a gradual decrease at high specific energy. ηloss has a contrary behavior. And ηgas increases steadily with the increase of specific energy. The ηreaction peak of 35.1% is achieved at specific energy of 0.17 J/cm3 at the conditions under investigation. Additionally, inlet gas temperature only has a small effect on energy conversion. Moreover, high gas temperature in discharge gap is confirmed to be not favorable for ozone formation from the view of reaction heat. The sensitivity coefficients of reactions with electron participation are sensitive to gas temperature. O+O2+O2→O2+O3 and O+O2+N2→N2+O3 account for about 70% and 30% of generated ozone respectively at the given conditions. And e+O2→e+O+O, N2(A)+O2→N2O+O, and N2(A)+O2→O+O+N2 are responsible for about 51.3%, 14.7%, and 32.0% of oxygen atom, respectively.