Hydrogenation of carbon dioxide into methanol on a Cu/Zn/Al₂O₃ catalyst in a fixed-bed reactor

The catalytic hydrogenation of CO₂ to CH₃OH has a bright prospect along with high market demand. Methanol (CH₃OH) was needed as raw material in the petrochemical industry to produce formaldehyde, chloromethane, amine acetate and also as an new alternative environmentally friendly energy. This study aims to obtain a Cu/Zn/Al₂O₃ catalyst design and the effect of feed temperature on CO₂ conversion, CH₃OH selectivity, and CH₃OH yield. The preparation of Cu/Zn/Al₂O₃ catalysts by co-precipitation method resulted in the percentage ratio of Cu/Zn/Al metal composition of 66,7: 27,4: 4,29 and the catalyst surface area of 98,3411 m²/g. The H₂:CO₂ ratio in the feed gas is 3: 1. The fixed-bed reactor has the dimension of 1.5 cm in inner diameter, 5 cm in length of reactor bed, and is equipped by a furnace upstream the reactor bed. The reaction was carried out at the pressure of 30 bar and the flowrate is kept constant. The feed temperature varies at 220, 250, 280°C. At the feed temperature of 250°C, the best performance is obtained: the CO₂ conversion of 21.8%, the CH₃OH selectivity of 82.76%, and the CH₃OH yield of 18.04%, which is reached after 240 minutes of the reaction (steady state).