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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