A comparison between plasma single and double dielectric barrier discharge reactors in terms of electrical characterization and products generation for methane slip oxidation application

The issue of methane slip from marine low-pressure LNG-fuelled engines has received increasing attention because it contributes to greenhouse gas emissions. In this study, methane conversion in non-thermal plasma single (DBD) and double (DDBD) dielectric barrier discharge reactors has been investigated experimentally at 200 °C. A comparison of the two reactors in terms of discharge characterization, CH4 conversion, NOx generation, and energy efficiency was performed. The result showed that the DBD reactor had stronger amplitude and intensity of current pulses while the DDBD reactor displayed higher applied voltage and specific input energy. CH4 conversion efficiency above 98 % was achieved in both reactors at high input power of 97.65 W. CO and CO2 were the only products of CH4 oxidation. Compared to the DBD reactor, Lower CO selectivity, higher CO2 selectivity, and much lower NOx formation were observed in the DDBD rector. The DBD reactor achieved the highest energy efficiency of CH4 conversion at low input power while the DDBD reactor showed the highest energy efficiency for product generation at high input power. Although the performance of both reactors in terms of methane conversion efficiency was quite close, the DDBD reactor had better performance in decreasing CO formation and NOx generation.