Abstract: A new high active unsupported Ni-W-Mo hydrotreating catalyst was synthesized and characterized by using X-ray powder diffraction (XRD), BET adsorption measurements, and transmission electron microscopy (TEM). Said unsupported Ni-Mo-W catalyst had considerable active sites and highly divided active phases, which led to its excellent thiophene hydrodesulfurization (HDS) activity and toluene hydrogenation (HYD) activity. Said unsupported catalyst was compared with a high active commercial supported catalyst on a 100 mL fixed bed pilot plant unit using Middle East straight-run diesel oil as feedstock. Test results showed that the HDS activity and HDN activity of said unsupported catalyst was almost 7 times and 3 times of the reference catalyst, respectively. Clean diesel fuel meeting the Euro-V emission standard could be obtained under relatively mild reaction conditions with said unsupported catalyst.

Key words: unsupported, activity, hydrotreating, catalyst, hydrodesulfurization