Influence of forced feed composition cycling on catalytic methanol synthesis

Studies have been carried out between 230 and 270°C and 1.97 and 2.93 MPa total pressure on the synthesis of methanol over an industrial catalyst of the copper‐zinc oxide‐alumina type using a gradientless reactor. Two modes of forced feed composition cycling were explored: periodic variations of the mole fraction of H 2 and CO and periodic variation of the CO 2 content. The latter mode substantially improved methanol production and suppressed the parasitic formation of methane, while the former mode had just the opposite effect. Measurements of methanol, methane and CO during a cycle as well as separate observations of the response to step‐changes in concentration indicated substantial storage of CO on the catalyst surface. Rapid response of methane to the CO 2 content suggests over‐reduced areas of the catalyst surface are responsible for methane formation and that these regions are readily oxidized. CO 2 or H 2 O associated with methane formation appear to relate to the dynamics of methanol formation.