CO2 reforming of biogas to obtain synthesis gas using non-thermal plasma

Abstract

Due to the high content of CO2 (40–50 mol%) in biogas, it is highly important to upgrade biogas. The usual methods for upgrading biogas involve the separation of CO2 from it. Alternatively, this paper reports the development of a new method for upgrading biogas, which is the CO2 reforming of biogas for gliding arc plasma-assisted production of synthesis gas. This work primarily includes four parts: (1) Basic discharge characteristics: the discharge characteristics of gliding arc plasma during the process of CO2 reforming of biogas can be divided into four stages. (2) The effects of input voltage: with the increase of input voltage, the volume fractions of CH4 and CO2 are reduced while those of H2 and CO are increased. (3) The effects of reaction time: with the extension of reaction time, the conversion rates of CH4 and CO2 are hugely increased from 30% to 34%, respectively, at 15 min to 90% and 84%, respectively, at 75 min; and the concentrations of H2 and CO are also obviously increased from 19.5 mol% to 13.08 mol%, respectively, at 15 min to 41.76% and 45.15%, respectively, at 75 min. (4) Lastly, the optimal power density in this work is 11 kW/(L/s) under the working conditions of 15 min and 7955 V, which is a notably good value for CO2 reforming of biogas with the assistance of plasma. Therefore, this paper is highly important for biogas upgrading.