Low pressure glow-discharge methanation with an ancillary oxygen ion conductor.

Plasma technology is gaining increased interest for the reduction of carbon dioxide (CO 2 ) to carbon monoxide (CO) and oxygen (O 2 ). CO is a reaction partner with hydrogen (H 2 ) to produce gas and fuel. This paper elaborates an improved method to produce methane (CH 4 ) by plasma induced dissociation of carbon dioxide and H 2 in one single setup. A low pressure glow discharge plasma with an integrated zirconia based ion conductor transports oxygen ions (O 2− ) in or out of the reaction chamber. Transporting oxygen ions into the reaction chamber is a way to have a controlled amount of water vapor for the conducted experiments. In contrast, leads the reduced amount of O 2 ions to a theoretical decrease in the recombination of CO and O 2 to CO 2 in the ionized gas and therefore increases the CO 2 conversion rate. The applied voltage to the ion conductor for the outward ion transportation and the power of the plasma source current have a major impact on the amount of extracted O 2− ions. The effect of these parameters on the CO production rate and the formation of methane are investigated. A positive effect of the plasma current on the amount of CO and CH 4 is detected. The influence of the temperature increase from the heated ion conductor relates to an undesired increase of the recombination rate of CO and O 2 to CO 2 , but has a positive effect on the methanation. [ABSTRACT FROM AUTHOR]