Comparison between the thermal and plasma (NTP) assisted palladium catalyzed oxidation of CH₄ using AC or nanopulse power supply

The combustion of methane using a plasma, a plasma-catalyst or a thermo-catalytic system was explored using a palladium supported on alumina catalyst. The three systems were compared in terms of their specific input energy (SIE*) and the potential presence of a synergistic effect between the plasma and the heterogeneous catalyst. For the plasma-catalyst system, an evaluation of the specific input of energy between systems using either a traditional AC or a nano-pulse power supply was also assessed. Based on the SIE*, the thermal process was more efficient than the plasma systems and no synergistic effect was found for the plasma systems when an AC power supply was used. Conversely, the nanopulsed operation showed greater promise since the energy requirements were reduced in both the homogeneous and heterogeneous configurations, showing high conversion at energy levels where the thermo-catalytic process with a commercial catalyst was not active.