Enhanced methanol production by two-stage reaction of CO2 hydrogenation at atmospheric pressure

Methanol can be produced from CO2 hydrogenation. CO2 was hydrogenated to CH3OH in one-stage reaction at atmospheric pressure. The result was highly selective to CH3OH but insufficient conversion of CO2 using Cu/Zn/Al2O3. A two-stage reaction was carried out with high and low temperatures, respectively. CO2 was hydrogenated to carbon monoxide (CO) and H2O in the first-stage at high temperatures. Subsequently, after removing H2O, CO was further hydrogenated to CH3OH in the second-stage at low temperatures. The CH3OH yield was 3.4 times higher than that of single-stage reaction. This concept achieves CO2 hydrogenation towards more CH3OH production.