Abstract: The S Zorb process can produce low sulfur gasoline. However, the final boiling point (FBP) of the product gasoline rises. To find the reason, the boiling ranges and compositions of the products before and after S Zorb process were investigated in a micro-fixed reactor using FCC gasoline and straight-run gasoline as feedstocks from SINOPEC Cangzhou Company and fromYanshan Refinery, respectively. Results show that the FBP of the product rises with the rise of the reaction temperature. The increase of aromatic hydrocarbons and high boiling point aromatics in heavy distillates, the existence of olefins which cause the increase of carbon number of the components are the primary reasons of the FBP rising. In addition to the hydrogenation of hydrocarbons < C5, the cyclization of alkanes and dehydro-aromatization of naphthene occurs as well. However, under laboratory conditions, the mole ratios of H/C change little.

Key words: S-Zorb, final boiling point, alkane cyclization, dehydro-aromatization, adsorption desulfurization