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

•A kinetic rate equation for CO2 reforming of CH4 in kHz spark plasma was established.•Rate constants of CH4 and CO2 conversion in the plasma at various f were obtained.•The dependence of the CH4 and CO2 conversion on pd value was investigated.•The reliability of the rate equation was verified.

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)XCH4,XCO2 on pd value (the product of p and d) and SEI   can be expressed as follows: XCH4/(1-XCH4)=kCH4·(pd)·SEIXCH41-XCH4=kCH4·(pd)·SEI and XCO2/(1-XCO2)=kCO2·(pd)·SEIXCO21-XCO2=kCO2·(pd)·SEI, where kCH4kCH4 and kCO2kCO2 are the rate constant of CH4 and CO2 conversion, respectively. Increasing f from 5 to 80 kHz, kCH4kCH4 and kCO2kCO2 increase from 0.78 and 0.53 mol·MJ−1·bar−1·mm−1 to 1.04 and 0.63 mol·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.

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