Low-Temperature CO<sub>2</sub> Splitting in a Noncatalytic Dielectric-Barrier Discharge Plasma: Effect of Operational Parameters with a New Strategy of Experimentation
M.R. Jahanbakhsh, Hamed Taghvaei, Omid Khalifeh, Mahla Ghanbari, Mohammad Reza Rahimpour
Abstract
In this study, low-temperature CO2 decomposition to CO was investigated experimentally through a dielectric-barrier discharge plasma reactor with the main objective of improving CO2 conversion and energy efficiency without using a catalyst. In this regard, the effects of key operating parameters including input power, total flow rate, and CO2 volume fraction were evaluated to find the best operating conditions. In contrast with the strategy of experimentation in previous studies at which every parameter has to be analyzed individually while others are kept constant, in this study, all combinations of the operating parameters were included and tested experimentally. There was a direct correlation between power and conversion, but this was less noticeable for higher powers. Thus, the highest conversion of 12.2% could be obtained at a power, CO2 fraction, and total flow of 30 W, 5%, and 400 mL/min, respectively. It was also observed that the maximum obtained energy efficiencies were related to the higher total flows and higher CO2 volume fractions; thus, the best energy efficiency was around 7% for a total flow of 400 mL/min and CO2 volume fraction of 25%. Besides, precise predicting correlations indicating the degree of sensitivity of conversion and energy efficiency toward variation of each parameter were developed based on full factorial experimental design. Analysis of variance demonstrated an excellent agreement between the experimental data and the proposed models. The strategy of experimentation that we adopted in this study gave us a new insight into the effects of operating parameters on the cold CO2 decomposition process relative to previous studies.