CO2 and CH4 conversion to syngas via membrane and plasma routes: Challenges and future directions

The increase in emissions of greenhouse gases (GHGs) such as CO2 is the main reason for global warming which has attracted considerable attention over the year. Dry reforming is one of the attractive processes among the CO2 conversion and utilization approaches due to its ability to convert both CO2 and CH4 into syngas. Catalytic membrane and non-thermal plasma catalytic reactors are promising technologies for CO2 and CH4 conversion. Non-thermal plasma-catalytic in particular benefits from its low energy consumption and ease of operation. In this review, the mitigation techniques for CO2 capture along with their advantages and disadvantages are initially presented. Then, catalytic membrane reactors for dry reforming are introduced, followed by an analysis on the effect of operating parameters as well as the presence of catalysts toward gas conversion. Non-thermal dielectric barrier discharge (DBD) plasma method for dry reforming is subsequently introduced and discussed. Furthermore, the challenges and problems of both technologies to form syngas are highlighted. Lastly, examples of integrated DBD plasma-membrane systems utilized in other processes are explored which leads to a discussion on the future directions of these technologies for CO2 and CH4 conversion.