Hydrodesulfurization and hydrodemetallization of different origin vacuum residues: Characterization and reactivity

This work presents an insight on the reactivities of different geographical origin residues in hydrotreatment processes. Hydrodemetallization (HDM) and hydrodesulfurization (HDS) experiments have been performed on different vacuum residue (Arabian Light, Buzurgan, Djeno and Ural) with commercial catalysts under industrial conditions. Depending on its origin each residue appears to have a specific behavior; however, some general trends can also be highlighted.One key reactivity parameter (both for HDM and HDS reactions) seems to be the size of residue molecules that depends strongly on its origin. In fact, diffusion limitations may occur, even in the HDM section.Hydrodesulfurization (HDS) reactions are not completely controlled by diffusion; the nature of chemical structures also appears to be an important parameter for reactivity. A better knowledge of the chemical structures is therefore still necessary to understand these different reactivities.

► Molecules size is key parameters for residue hydrotreatment, especially in the HDS section.
► HDV reactions are controlled by diffusion limitation.
► Removal of Nickel is more difficult than that of vanadium.
► High hydrogenating activity of HDS catalysts increases the removal of sulfur in the aromatics.
► Djeno residue contains highly refractory sulfur molecules.