Factors Influencing the Deactivation of Industrial Catalysts I. Co-Mo-A1203 Hydrodesulfurization Catalysts

The changes that occurred in tbe physico-chemical properties of a commercial Co-Mo-A1203 catalyst on industrial usage were examined. The catalyst under study had operated satisfactorily, meeting the full guarantees on its life, but had to be discarded after six regenerations due to shortened cycle lengths. It was observed that changes in the texture and structure of the support alumina and loss of the active components (Mo03 and CoO) had occurred. Also, the spent catalyst was found to be more acidic, resulting in faster coke pick up during reaction. Some evidence for the weakening of the Mo03 - A1203 interaction was also noticed. The reasons for the above changes in the physico-chemical properties, believed to be responsible for the short cycle lengths of the catalyst, are analysed