Comparative study on the performance of microwave-assisted plasma DRM in nitrogen and argon atmospheres at a low microwave power

Abstract

Dry reforming of methane (DRM) is an attractive route to convert CH4 and CO2 into syngas (a mixture of CO and H2). In this work, the performance of microwave-assisted DRM at atmospheric pressure (in terms of CH4 and CO2 conversions, H2 and CO selectivities, H2 and CO yields, and H2 to CO ratio) is studied as functions of additive gas flow rate, microwave power, CO2 to CH4 inlet supply ratio, and reaction time. Two additive gases were used, i.e., nitrogen and argon. Microwave-assisted DRM experiments in both gases show identical trend of conversions, selectivities, yields, and product ratio. DRM performances in both additive gases atmosphere were stable for up to 8 h. Under the same operating conditions, using Ar as an additive gas, however, led to higher H2 and CO selectivities and yields and thus, higher H2 to CO ratio relative to using N2 as an additive gas. Maximum CH4 and CO2 conversions of 79.35% and 44.82%, H2 and CO selectivities of 50.12% and 58.42%, H2 and CO yields of 39.77% and 32.89%, and H2 to CO ratio of 0.86 were obtained at 700 W and N2, CO2, and CH4 flow rates of 1.5, 0.4, and 0.2 L min−1, respectively.