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.