Effect of enrichments on the CH₄ yield and CO₂ conversion in a Sabatier process modeled in a microchannel reactor.

Sustainable energy systems for the future are gaining interest in terms of reducing carbon emissions and efficiently utilizing CO₂. The Sabatier reaction is one which has the potential to convert the atmospheric CO₂ into methane (fuels), and has attracted attention of the researchers because of its applications in the power to gas technology and space exploration missions. The Sabatier process, which is a catalytic reduction of CO₂ into methane, is highly reversible and exothermic in nature, and requires a higher than ambient temperature for occurrence. It is usually accompanied by a reverse water gas shift (RWGS) reaction, which results in an oxidizer-fuel (O/F) ratio of 3.5:1, as opposed to 2:1 with the Sabatier process alone. In the current study, a CFD model is developed to describe the reaction-coupled transport phenomena and effect of enrichments on the conversion of CO₂ and methane yield inside a microchannel reactor at different temperatures and pressures to determine the optimum operating conditions. The use of a microchannel reactor helps in providing a better thermal and mass transfer performance, while providing savings in space requirements. In addition, H₂ and CO₂ enrichment studies conducted here, deliver significant gains in terms of methane yield and CO₂ conversion, and also present very interesting effects on the reaction rates and associated products. In summary, a detailed set of parametric CFD studies of the Sabatier reaction help in identifying the optimal reactant ratios in order to achieve the highest efficiency