OPTIMAL CATALYST ACTIVITY PROFILES IN PELLETS .9. STUDY OF ETHYLENE EPOXIDATION

The concept of optimal catalyst activity distribution is studied experimentally for the ethylene epoxidation reaction network on a Ag/alpha - Al2O3 catalyst in a single-pellet reactor. The Dirac delta-type distribution of the catalyst is approximated by a step distribution of narrow width. For a fixed amount of silver, the influence of location and width of the catalytically active layer on the conversion of ethylene and on the selectivity and yield to ethylene oxide is investigated under oxygen-rich conditions in the temperature range 210-270-degrees-C. The results clearly demonstrate that for optimum selectivity and yield to ethylene oxide, the silver catalyst should be placed in a thin layer at the external surface of the pellet.