Abstract: The unloading and ex-situ regeneration of catalyst, and restarting for 2.0 Mt/a diesel hydrotreating unit and problems occurred during these stages were introduced. The solutions for solving above problems were suggested. The calibration results indicate that the activity of the regenerated catalysts recovers well, close to the fresh catalyst. The hydrodesulfurization rate reaches 98.5%, and the sulfur content in diesel product is 170 μg/g, when a mixed feedstock of straight-run diesel and FCC diesel is processed.

Key words: diesel hydrotreating, catalyst, regeneration, startup