Numerical modeling and mechanism investigation of nanosecond-pulsed DBD plasma-catalytic CH4 dry reforming

Abstract

Plasma-catalytic CH4 dry reforming is an emerging technology that takes advantage of plasma-catalysis interactions to implement the conversion of CH4 and CO2 into syngas and valuable chemicals. In this work, an experiment is conducted to determine the reduced electric field E/N in the numerical modeling. In addition to essential reactor parameters, catalysis characteristics are integrated into the modeling. The 3D geometry of a nanosecond (ns) pulsed DBD plasma reactor for plasma-catalytic CH4 dry reforming is reduced into a 0D kinetics model to investigate the inherent plasma-catalysis mechanisms. The simulation results indicate that C2O4 + and CH4 +, H and O, and CH4(v 13) are the dominant ions, radicals and vibrationally excited species, respectively. Although the reactions related to CH4 and CO2 consume 19.7% and 80.3% of the total electron energy, the electron energy loss caused by the CH4 ionizations (1.3%) is distinctly higher than that caused by the CO2 ionizations (0.4%). Surface reactions can generate a large amount of adsorbed species CH3(s), H(s), CO(s) and O(s). An amount of 77.2% of formaldehyde is produced by the reaction between CH3 and O. In addition, methanol is derived from the reactions between CH3 and OH in the pulsed dielectric barrier discharge (DBD) plasma catalytic reforming CH4/CO2. This numerical modeling reflects the practical plasma-catalysis system and therefore should be a novel tool to further understand the complicated underlying mechanism of the ns-pulsed DBD plasma-catalytic CH4 dry reforming.