CO₂ reduction using non-thermal plasma generated with photovoltaic energy in a fluidized reactor

The aim of this work was to study the efficiency of a fluidized plasma reactor (FPR) coupled to a photovoltaic system to reduce CO₂ to CO at atmospheric pressure and low temperatures. The major products of this reaction were CO and O₂, which suggests that the stoichiometric conversion of CO₂ into CO and O₂ was achieved. The results indicate that increasing the number of discharge points in the anode, voltage and frequency, the conversion of CO₂ to CO increased due to the a higher number of random non-thermal plasma (NTP) discharges generated in the FPR. An increase of the gap between the electrodes resulted also in higher conversions. At higher CO₂ flowrate, the CO₂ conversion decreased but the energy efficiency increased. The addition of low concentration of copper in the alumina fluidized bed resulted in a slight improvement of the CO₂ conversion and energy efficiency. The maximum CO₂ conversion and energy efficiency obtained in this study were 41% and 2.1% respectively. From a life cycle assessment approach, it was concluded that the use of photovoltaic energy coupled to the FPR technology improve the sustainability of the process. It was estimated that with the optimal conditions obtained in this work, it would be possible to compensate 67% of the CO₂ emissions associated to the process.