Transient Effects during Dynamic Operation of a Wall-Cooled Fixed-Bed Reactor for CO2 Methanation

Abstract

The power-to-gas process is an option to transform fluctuating renewable electric energy into methane via water electrolysis and subsequent conversion of H2 by methanation with CO2. The dynamic behavior of the methanation reactor may then be a critical aspect. The kinetics of CO2 methanation on a Ni-catalyst were determined under isothermal and stationary conditions. Transient isothermal kinetic experiments showed a fast response of the rate on step changes of the concentrations of H2, CO2; in case of H2O, the response was delayed. Non-isothermal experiments were conducted in a wall-cooled fixed-bed reactor. Temperature profiles were measured and the effect of a changing volumetric flow was studied. The experimental data were compared with simulations by a transient reactor model.