Dry reforming of CH4[sbnd]CO2 in AC rotating gliding arc discharge: Effect of electrode structure and gas parameters

Abstract

Conversion of CH4 and CO2 into synthesis gas has been performed in a rotating gliding arc discharge (RGAD) reactor driven by a high frequency AC power. Influence of electrode structure and gas parameters on RGAD plasma CH4CO2 conversion and energy efficiency of the process was investigated. Summit angle of internal electrode is an important parameter affecting the stability of the reaction. Internal electrode with summit angle of 45° is more favorable for CH4 and CO2 conversions. The energy efficiencies increase by 25% and 22% than those in RGAD involving internal electrode with summit angle of 30° and 60°, respectively. Longer external electrode improves the arc extension leading to an increase of 17% and 25% in CO2 and CH4 conversion at the applied voltage of 11 kV. Feed flow rate has significant impact on the CO2 and CH4 conversion, while low CO2/CH4 ratio inhibits rotating gliding arc extension due to carbon-black deposition. A large number of graphene quantum dots have been observed to generate on the lamellar ley of the carbon-black. Maximum energy efficiency of 3.9 mmol/kJ is achieved at feed flow rate of 3 L/min and CO2/CH4 ratio of 3:2 in this work.