Investigation of simultaneous reaction of carbon monoxide and carbon dioxide with hydrogen on a commercial copper/zinc oxide catalyst

The kinetics of low-pressure methanol synthesis from CO, CO2 and H2 on a commercial Cu/ZnO catalyst was investigated in a Berty-type reactor at low overall conversion to reduce the influence of chemical equilibria (reaction conditions: p = 3–5 MPa, T = 483–543 K). At constant H2 partial pressure the ratio of CO to Co2 was varied. The results show that the rate of methanol production depends strongly on the age of the catalyst and less strongly on the feed composition. The fresh catalyst gives a maximum rate with an H2:CO:CO2 ratio of 70:28:2, whereas the deactivated catalyst gives maximum rates if a synthesis gas with ratio 70:0:30 is used. The activation energy of methanol synthesis from CO2 and H2 is considerably lower than that from CO and H2. The experimental results shed useful light on three contradictory kinetic equations published in the past decade.