Carbon dioxide reforming of methane by pulsed glow discharge at atmospheric pressure: The effect of pulse compression

Methane reforming by carbon dioxide in pulsed glow discharge at atmospheric pressure is examined. The plasma pulse is compressed to less than 50 ns. This compression enables one to work at higher frequencies, over 3 kHz, without glow-arc transition. The main products of the reaction are synthetic gases (H-2, CO) and C-2 hydrocarbons. Approximately 42% of plasma energy goes to the chemical dissociation, when the reactant ratio is CO2/CH4=1. At this point, the energy expense is less than 3.8 eV per converted molecule while reactant conversions are relatively high reaching to 55% (CH4) and 42% (CO2). The reactor energy performance even gets better at higher CO2/CH4 ratios. While energy efficiency reached about 45%, at feed ratio of CO2/CH4=5, the conversions of about 65% and 45% were obtained for methane and carbon dioxide, respectively. A model describing dissociation through molecular vibrations is introduced. According to the model, the high nonequilibrium state of vibrational energy at short pulses leads to this improvement, especially in carbon dioxide. (c) 2007 American Institute of Physics.