Sorption enhanced CO2 hydrogenation reactions are a promising technological approach for process intensification in the context of Power-to-X and CCU. Due to the in-situ removal of reaction products, the chemical equilibrium can be shifted towards higher conversions while additionally leading to higher reaction rates. CO2 hydrogenation reactions, i.e. methanol synthesis, methanation or the reverse water-gas-shift reaction (rWGS) form water as a byproduct. Water can be adsorbed on many different material types including zeolites, salt chlorides and metal oxides.
This work presents systematic experimental investigation of different sorption materials at reaction conditions, also accounting for co-adsorption phenomena. Our results indicate that common Linde Type A- and Y-zeolites provide substantial water sorption capacity and favorable kinetics up to 350 °C, while co-adsorption of CO2 as the most critical component plays a minor role, if an appropriate zeolite is chosen.
These experiments are accompanied by a kinetic model and integrated into a dynamic reactor simulation of a sorption-enhanced rWGS reactor in which the endothermic reaction is coupled with the exothermic adsorption of water.
Based on these experimentally validated simulations a new highly energy-optimized process scheme for the production of syngas e.g. for Fischer-Tropsch application is presented, that reduces the process temperature by more than 600 °C.