Computational investigations of enrichment effects for CO2 methanation in Sabatier microchannel reactors

Abstract

The Sabatier micro-reactor for CO2 reduction through methanation, in manned mission applications, has gained a lot of interest due to higher yields of fuel and improved logistics. Three-dimensional (3D) computational fluid dynamics (CFD) calculations of flow, heat transfer and chemical reactions are performed here to understand and evaluate the potential of H2 and CO2 enrichment to increase the efficiency of the CO2 methanation in Sabatier microchannel reactors. The model is first validated by comparing calculations of the stoichiometrically-fueled reaction with previously conducted experiments at varying temperatures and pressures. A comprehensive set of studies at different H2 and CO2 enrichment levels, temperatures ranging from 200 to 400∘C and gauge pressures of 1 bar and 5 bar is carried out. Results show that yields and conversions of almost 100% are achievable with the highest H2 enrichment levels at the highest temperature and pressure tested here, with a desirable control of CO emission.