Effects of space velocity on methanol synthesis from CO2/CO/H-2 over Cu/ZnO/Al2O3 catalyst

Abstract

The space velocity had profound and complicated effects on methanol synthesis from CO2/CO/H-2 over Cu/ZnO/Al2O3 at 523 K and 3.0 MPa. At high space velocities, methanol yields as well as the rate of methanol production increased continuously with increasing CO2 concentration in the feed. Below a certain space velocity, methanol yields and reaction rates showed a maximum at CO2 concentration of 5-10%. Different coverages of surface reaction intermediates on copper appeared to be responsible for this phenomenon. The space velocity that gave the maximal rate of methanol production also depended on the feed composition. Higher space velocity yielded higher rates for CO2/H-2 and the opposite effect was observed for the CO/H-2 feed. For CO2/CO/H-2 feed, an optimal space velocity existed for obtaining the maximal rate.