Dynamic operation of fixed-bed methanation reactors: Yield control by catalyst dilution profile and magnetic induction

Abstract

Dynamic operation of fixed-bed methanation reactors has been subject to increasing research efforts over the past years, as a consequence of its potential interest for the energy transition (power-to-gas). Due to the reaction exothermicity, the thermal management of a reactor is particularly difficult. In the present work, a model and a software are developed to simulate the behavior of a reactor whose reaction medium contains a mixture of catalytic pellets and induction-sensitive pellets. The study shows that a reactor made-up of two reaction zones of different catalytic fractions can produce a gas of identical steady-state compositions for two different flow rates. A steep shift from the low to the high inflow rate generates a transient drop in the methane yield. Magnetic induction rapidly heats up an appropriate portion of the reaction medium, so that the yield remains nearly constant during both transient and steady state after a flow rate shift. This study constitutes a first step towards the final aim of using induction and catalyst dilution profile to stabilize the yield for any flow rate variation in a given range.