Investigation of CO2 Splitting Process Under Atmospheric Pressure Using Multi-electrode Cylindrical DBD Plasma Reactor

In this paper, the CO2 splitting process was performed under atmospheric pressure in a multi-electrode cylindrical dielectric barrier discharge (DBD) plasma reactor. The influence of the plasma processing parameters including discharge voltage, discharge length and gas flow rate was investigated. Besides, the effect of the similar specific energy input (SEI) values obtained using different plasma powers and gas flow rates was studied. The experimental results indicated that the CO2 conversion and energy efficiency increased along with the increased discharge length due to the increased residence time and the enhanced electric field. The increase of the applied voltage and hence the plasma power or the decrease of the gas flow rate generated enhanced effect on CO2 conversion while negative influence on energy efficiency. In addition, by comparing the energy efficiency at similar SEI values obtained with different discharge powers and gas flow rates, it was found that the gas flow rate played a more important role in CO2 conversion. The proposed multi-electrode plasma reactor led to the highest CO2 conversion of 18.50% and maximum energy efficiency of 12.83%. Compared with other types of cylindrical DBD plasma reactors, the multi-electrode design proposed in this work can give a similar CO2 conversion and higher energy efficiency. The multi-electrode design can enhance the local electric field at the electrode edges, leading to the enhanced corona discharge and the generation of more micro-discharges, which is considered to be responsible for enhanced CO2 conversion process.