Experimental Investigation of Sorption-Enhanced CO2 Hydrogenation to Methanol

Water removal through adsorption on zeolite13X in the CO2 hydrogenation reaction significantly increasesthe activityand methanol production. In this work, we investigate experimentally the use ofzeolite13X as an efficient water sorbent in the sorption-enhanced CO2 hydrogenation reaction over Cu/ZnO/Al2O3 under different operating conditions and over multiple reaction-regenerationcycles. Introduction of the solid sorbent along with the catalystin the reactor leads to a prominent increase in the CO2 conversion and CH3OH yield. As the reaction proceeds,the sorbent gradually becomes saturated, the enhancement effect reduces,and the system eventually reaches the same steady state as with catalystonly. The CH3OH yield increase is higher than that of theCO(2) conversion, indicating preferential enhancement ofmethanol production. This can be attributed to the partial co-adsorptionof both methanol and water on zeolite 13X. The effects of reactionand regeneration temperature on the activity, product distribution,enhancement degree, and recyclability are also examined. The highestsorption enhancement occurs at 225 & DEG;C, with the methanol yieldincreasing by 115% compared to the conventional process. The cyclicstability is investigated by consecutive reaction-regenerationcycles. The correlation between activity reduction and textural propertiesof both the catalyst and sorbent as well as the zeolite's abilityto regenerate are explored. To that end, the effect of regenerationtemperature on the products' desorption is also examined.