Model analysis of atmospheric non-thermal plasma for methane abatement in a gas phase dielectric barrier discharge reactor

A physical model of a non-thermal plasma reactor for the abatement of CH4 emissions is presented. The model includes mass balances for neutral, charged and radical species, the enthalpy balance for the gas phase and specific equations for electron temperature and density. The kinetic scheme of CH4 abatement couples the GRI-Mech set of radical reactions (325 steps) with ten sets of plasma reactions (108 steps), which comprise elastic collisions, direct ionization, dissociative ionization, excitation and attachment reactions. The model is validated based on literature results that explore the effects of Specific Input Energy, gas temperature and H2O addition. The results highlight that dissociative electron-impact reactions produce chemically active OH and O radicals, which boost CH4 conversion, making H2O a key abatement promoter in the plasma process. The heating effect induced by electron collisions is relevant, suggesting that an accurate control of thermal insulation is crucial to characterize the reactor performance. (C) 2019 Elsevier Ltd. All rights reserved.