Methanol Formation in the Water Gas Shift Reaction over Copper-Containing Catalysts

In ammonia and hydrogen production, methanol formation takes place mainly at the low-temperature (second) WGS stage, where the gas composition, catalysts, and operating conditions are similar to those in methanol synthesis. The methanol formation reaction consumes hydrogen, an expensive gas, and causes a number of technological and environmental problems. This raises the problem of reducing the methanol formation rate. To do this, it is necessary to analyze the kinetics, thermodynamics, and technological features of methanol formation at the low-temperature shift stage. Here, we report the equilibrium methanol concentrations calculated for CO conversion under near-industrial conditions. Systematizing the relevant experimental data available from the literature, we demonstrate how methanol formation depends on WGS conditions. The methanol formation rate can be reduced by lowering the CO concentration in the feed gas and employing low-methanol catalysts. Another favorable factor for methanol reduction is the aging of the catalyst during its operation.