Deep hydrodesulfurization of DBT and diesel fuel on supported Pt and Ir catalysts

Deep hydrodesulfurization (HDS) of dibenzothiophene (DBT) and diesel fuel (0.08 wt,-% S) has been carried out on Pt and Ir supported on amorphous silica-alumina (ASA) and on a stabilized HY zeolite under standard industrial conditions. The effect of temperature, two different supports and feedstocks on HDS and hydrogenation (HYD) product selectivities are investigated, Normalized activity data indicate that in the HDS of DBT and of diesel fuel, the platinum catalysts are much more active than the iridium counterparts. In HDS of diesel fuel (at 623 K), both Pt/HY and Pt/ASA are a little more active than a commercial Co-Mo/Al2O3 catalyst. The normalized activity in the HDS of DBT (593 K) increases in the following order: Pt/HY > Pt/ASA much greater than Ir/HY > Ir/ASA, and in the HDS of diesel fuel (623 K), increases according to: Pt/HY much greater than Pt/ASA much greater than Ir/HY > Ir/ASA. All spent catalysts were characterized by X-ray photoelectron spectroscopy (XPS). In view of their superior performance, both platinum catalysts were characterized by FTIR spectroscopy of CO probe.