Deactivation of platinum on chlorinated alumina catalyst in the light naphtha isomerization process

Abstract

In order to maintain and increase the lifetime of platinum on chlorinated alumina catalyst, its deactivation was investigated in the presence of oxygenated compounds or mercaptans in the light naphtha hydroisomerization process. A high concentration of methanol or dimethyl disulfide (DMDS) in the feed resulted in irreversible and reversible deactivation of the catalyst. The degree of deactivation and activity recovery of the catalysts measured in the light naphtha isomerization and benzene hydrogenation reactions. The experimental results indicated that when the catalyst was deactivated with oxygenated compounds such as methanol, the catalyst activity was lost drastically, and the regeneration treatment was unable to restore the catalyst’s initial activity. However, a full recovery of the catalyst may obtain when deactivation occurred with dimethyl disulfide. It found that oxygenated compounds affect the acidic functional groups, but mercaptans had an important influence on metallic sites of the catalyst.