Deactivation of Pt/SO42−/ZrO2 Catalyst with Sulfur Compounds and Preventive Measures

Hydrodesulfurization of feed oil stocks is essential for the industrial isomerization process of light naphtha, because the isomerization catalysts are deactivated by small amounts of sulfur compounds. In this study, the deactivation of Pt/SO42−/ZrO2 catalyst by various sulfur compounds was examined, and reactions to suppress the deactivation were proposed. Various sulfur compounds caused rapid deactivation of Pt/SO42−/ZrO2 catalyst, in the order of (n-C3)2S2 >> Et-S-Me >> i-C3SH > H2S. The order of deactivation seems to depend on the adsorption of the sulfur compound on the active site. In order to suppress deactivation of the isomerization catalyst, a two reactor process combining hydrodesulfurization (HDS) and isomerization was examined. HDS followed by Pt/SO42−/ZrO2 catalyst isomerization showed stable activity for light naphtha with relatively high sulfur content.