Intra-particle diffusion limitations in low-pressure methanol synthesis

The dusty gas diffusion model was applied for the description of intra-particle diffusion limitations in methanol synthesis over a commercial CuZnAl catalyst. Experimental kinetic data were obtained at p = 10–50 bar and T = 210–275°C using a spinning basket reactor and a fixed bed catalytic reactor, starting from carbon monoxide, carbon dioxide and hydrogen. The results, obtained from experiments with two different catalyst particle sizes, show that commercial size catalyst particles exhibit intra-particle diffusion limitations. Combining the dusty gas diffusion with kinetic rate expressions for methanol formation from CO, methanol formation from CO2 and the water-gas shift reaction, good agreement with experimental data was obtained.