Kinetics study on carbon dioxide reforming of methane in kilohertz spark-discharge plasma

Abstract

The kinetics of CO2 reforming of CH4 in kilohertz spark-discharge plasma was studied. At CH4/CO2 ratio of 1, the effects of specific energy input (SEI), electrode gap (d), total pressure (p) and frequency of the applied voltage (f) on the reactant conversions and C-based and H-based selectivities were investigated. Thereby, the kinetic rate equation for CO2 reforming of CH4 in spark-discharge plasma was established. The dependence of the CH4 and CO2 conversions XCH4,XCO2 on pd value (the product of p and d) and SEI can be expressed as follows: XCH41-XCH4=kCH4·(pd)·SEI and XCO21-XCO2=kCO2·(pd)·SEI, where kCH4 and kCO2 are the rate constant of CH4 and CO2 conversion, respectively. Increasing f from 5 to 80kHz, kCH4 and kCO2 increase from 0.78 and 0.53mol·MJ−1·bar−1·mm−1 to 1.04 and 0.63mol·MJ−1·bar−1·mm−1, respectively. The reliability of the rate equation was verified by a comparison between the calculated value and the experimental data.