Microwave-assisted dry reforming of methane

Abstract

The microwave-assisted dry reforming of methane over an activated carbon, which acted as catalyst and microwave receptor, was investigated. As a preliminary study, the CO2 reforming of CH4 was carried out using conventional heating and microwave heating in order to compare both heating devices. Higher conversions of CH4 and CO2 were achieved by microwave heating. Under microwave heating, various operating variables were studied in order to determine the best conditions for performing dry reforming with high conversions and the most suitable H2/CO ratio. Thus, the dry reforming reaction was studied at different temperatures. An optimum range of working temperatures (between 700 °C and 800 °C) was established. In this range of temperatures, the dry reforming reaction is believed to take place as a combination of CH4 decomposition and CO2 gasification. Carbonaceous deposits from CH4 decomposition are gasified by CO2 and, as a result, active centres for the dry reforming reaction are constantly regenerated. The effect of the proportion of CO2 fed in on the CH4 and CO2 conversions was also investigated. Small increases in the percentage of CO2 fed in gave rise to large increases in both conversions, but especially in the case of CH4. The volumetric hourly space velocity was also studied. It was found that the lower the space velocity, the higher the conversions obtained.