Impacts of Alumina Introduction on a Pt–SO4/ZrO2 Catalyst in Light Naphtha Isomerization

Alumina-promoted Pt–SO4/ZrO2 catalysts (termed as PtSZAl) with excellent stability were prepared for isomerization. In the present work, the impacts of alumina on structure, surface properties, isomerization activity, and stability were investigated. The results of characterizations showed that alumina introduction improved the stability of tetragonal zirconia and increased the pore volume and the Brunauer–Emmett–Teller surface area. In addition, alumina also improved the water capacity of the catalyst, which contributed to better stability when the moisture content in the feed was high. The long-term life test was evaluated by n-hexane and reforming topping oil in about 1000 h. The conversion of n-hexane was higher than 90%, and the research octane number of reforming topping oil was increased from 62.8 to 79.3. Moreover, the used catalyst was regenerated nine times and the activity was almost not reduced, which proved that the reusability of PtSZAl catalysts was perfect.