Simulation Enhancement of CO 2 Hydrogenation to Methanol With Water Removal Membrane

ABSTRACT The integration of carbon dioxide (CO 2 ) with green hydrogen (H 2 ) for methanol synthesis presents a viable alternative to conventional fossil fuel‐based production routes under the background of carbon emission reduction. However, the synthesis reaction is thermodynamically limited and the byproduct of H 2 O would deactivate catalysts. The water removal membrane is introduced to improve the synthesis process and a coupled multiphase catalytic membrane reaction model has been established to investigate the enhancement of methanol synthesis due to the water removal in CO 2 hydrogenation. Results demonstrate that the selective permeability of water removal membrane both for countercurrent and co‐current flow lead to the significant improvement to the CO 2 conversion and methanol yield. The former flow type exhibits higher ΔP H2O around the outlet of the reaction channel (RC), higher maximum for H 2 O concentration in the sweep gas channel (SC), but may cause reverse H 2 O permeability around the inlet of RC, while the later flow shows a slightly lower average driving force but a relatively smooth water removal process. The optimization analysis show that the performance of membrane reactor can be significantly improved with the increase of reaction temperature and, pressure or H 2 /CO 2 . For the membrane reactor with co‐current flow at 513 K, 5.5 MPa and 0.015 m/s, CO 2 conversion increase up to 50% and methanol yield up to 56%, which are much higher than that of fixed‐bed reactor.