Experimentation and CFD modelling of a microchannel reactor for carbon dioxide methanation

The methanation of carbon dioxide (CO2) via the Sabatier process is increasingly gaining interest for power-to-gas application. In this investigation, a microchannel reactor was evaluated for CO2 methanation at different operational pressures (atmospheric, 5 bar, and 10 bar), reaction temperatures (250–400 °C) and space velocities (32.6–97.8 L.gcat−1.h−1). The recommended operation point was identified at reactor conditions corresponding to 5 bar, 400 °C, and 97.8 L.gcat−1.h−1. At this condition, the microchannel reactor yielded good CO2 conversion (83.4%) and high methane (CH4) productivity (16.9 L.gcat−1.h−1). The microchannel reactor also demonstrated good long-term performance at demanding operation conditions relating to high space velocity and high temperature. Subsequently, a CFD model was developed to describe the reaction-coupled transport phenomena within the microchannel reactor. Kinetic rate expressions were developed and validated for all reaction conditions to provide reaction source terms for the CFD modelling. Velocity and concentration profiles were discussed at different reaction conditions to interpret experimental results and provide insight into reactor operation. Overall, the results reported in this paper could give fundamental design and operational insight to the further development of microchannel reactors for CO2 methanation in power-to-gas application