Dry reforming process using microwave plasma generator with high carbon dioxide conversion efficiency for syngas production

Abstract

The proposed CO2 reforming solution has improved CO2 conversion efficiency by developing a new double helix type plasma generator (DHTPG) to preheat the discharge gas and increase residence time of CO2 at DHTPG. In addition, injecting CH4 independently allows for a stable increase in the temperature of the CO2 plasma in the microwave plasma generator compared with other conventional methods. To verify the performance of the DHTPG, we experimentally investigated the distribution of the plasma gas temperature using an enthalpy probe system as a function of the specific energy input, which is a key parameter for understanding the mechanisms of CO2 reforming of CH4. We performed the CO2 reforming of CH4 using the newly designed plasma generator and a comparative analysis of its characteristics with those of other plasma generators. Without catalyst materials, our method significantly enhanced the CO2 conversion efficiency to 91.4 % with an energy efficiency of 67 % at a specific energy input of 245 kJ/mol. The main advantage of our method is an increase in energy-consumption selectivity, in which the energy injected through the plasma decomposes CO2 rather than CH4. In addition, it reduces the energy required to stably maintain the plasma to improve energy efficiency.