Study of energy consumption in a laboratory pilot plant for the microwave-assisted CO2 reforming of CH4

In this work the microwave-assisted CO2 reforming of CH4 over carbon-based catalysts, carried out in a lab-scale microwave pilot plant, was investigated focusing on the conversions achieved and energy consumption. The activated carbon, FY5, and a heterogeneous mixture of FY5 and an in-lab prepared Ni/Al2O3 were selected as catalysts. Regardless of the catalyst used (FY5 or FY5 + Ni/Al2O3), high and steady CH4 and CO2 conversions were obtained. However, the catalytic activity of the heterogeneous mixture of FY5 and Ni/Al2O3 was found to be better. Energy consumption values of the scale-up microwave-assisted CO2 reforming of CH4 reaction were estimated from the experimental data and a flow rate of 1 m3 h− 1 of introduced CH4 was used as calculation basis. An energy consumption of 44.4 kW·h per m3 of H2 produced, with FY5 as catalyst, and of 4.6 kW·h per m3 of H2 produced, with FY5 + Ni/Al2O3, was estimated. A comparison of these estimations with bibliographic values of energy consumption for steam methane reforming (1.2 kW·h per m3 of H2 produced), showed the microwave-assisted CO2 reforming of CH4 over mixtures of activated carbon and metal-based catalyst to be a promising process able to rival the steam reforming process.

► Energy consumption of microwave-assisted CO2 reforming of CH4 was estimated.
► A lab-scale microwave pilot plant was used as the heating device.
► The activated carbon, FY5, and a mixture of FY5 and Ni/Al2O3 were used as catalysts.
► Energy consumption was 4.6 kW·h per m3 of H2 using FY5 + Ni/Al2O3 as catalyst.
► Microwave-assisted CO2 reforming of CH4 over FY5 + Ni/Al2O3 may be able to rival SMR.