Pure methane from CO₂ hydrogenation using a sorption enhanced process with catalyst/zeolite bifunctional materials

Abstract

Methanation is a potential large-scale option for CO₂ utilization, and it is one of the solutions for decreasing carbon emission and production of synthetic green fuels. However, the CO₂ conversion is limited by thermodynamics in conventional reaction conditions. However, around 100 % conversion can be obtained using sorption enhanced CO₂ methanation according to Le Chatelier's principle, where water is removed during the reaction using zeolite as a sorbent. In this work 5%Ni5A, 5%Ni13X, 5%NiL and 5%Ni2.5%Ce13X bifunctional materials with both catalytic and water adsorption properties were tested in a fixed bed reactor. The overall performance of the bifunctional materials decreased on going from 5%Ni2.5%Ce13X, 5%Ni13X, 5%Ni5A, to 5%NiL. The CO₂ conversion and CH₄ selectivity were approaching 100 % during prolonged stability testing in a 100 reactive adsorption – desorption cycles test for 5%Ni2.5%Ce13X, and only a slight decrease of the water uptake capacity was observed.