Carbon dioxide reforming of methane in kilohertz spark‐discharge plasma at atmospheric pressure

The spark‐discharge plasma, generated between tubular and rotary‐disc electrodes using a sine‐wave high voltage with 5 kHz frequency, was explored for CO2 reforming of CH4. Based upon the investigation on the effects of specific energy input and CO2/CH4 ratio, the energy costs (EC) and fuel‐production efficiencies (η) at various CO2/CH4 ratios (r) in the same conversion range were compared and accordingly their sequences were given: EC (r = 0.5) and EC (r = 3) are the lowest; η(r = 0.5) is the highest. Compared with other nonthermal discharge techniques, the kilohertz spark discharge exhibits low EC and high fuel‐production efficiency, especially at high total‐carbon conversions. Preliminary investigation on partial oxidation and CO2 mixed reforming at (O2 + CO2)/CH4 = 0.5 exhibited high H2/CO ratio (nearly 2) and low total‐carbon EC (0.59–0.96 MJ/mol, 58–77% of total‐carbon conversion, and O2/(CO2 + O2) = 0.8).