An optimized reactor for CO2 splitting in DC atmospheric pressure discharge

Direct current atmospheric pressure discharges offer a unique set of properties, that make them ideal for the splitting of CO2. In this study, a reactor with a maximum plasma power of 220 W is presented that operates in the glow-to-arc transition region. It facilitates the splitting of CO2 with up to 43% energy efficiency in the plasma at a high CO2 conversion of 27%. The goal of this study was to improve the splitting efficiency of CO2 and gain an understanding for the scaling effects involved in the process. To achieve this, a tubular plasma reactor with adequate driver was constructed, in which the discharge is formed between a pin and ring electrode. The reactor represents an improved version of our previous design, utilizing optimized gas flow. The plasma is forced into a disc-like volume by an axial magnetic field. The relationship of electrical characteristics of the plasma and the applied magnetic field were studied successfully. It was revealed that the magnetic field can be used to tune the burn voltage and stabilize the plasma. The shape and rotation rate of the plasma in the magnetic field were investigated. Splitting of CO2 was performed under a wide range of parameters, the ideal operation conditions could be determined.