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: ECmath image (r = 0.5) and ECmath image (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). © 2010 American Institute of Chemical Engineers AIChE J, 2011