Abstract: An asphaltene-containing oil hydrodesulfurization process employing a guard reactor and a main reactor in series, with the diameter of the guard reactor being smaller than the diameter of the main reactor. The catalyst in the guard reactor comprises particles of supported Group VI and Group VIII metals in the form of elongated extrudates whose surface is provided with a plurality of alternating longitudinal grooves and protrusions. An advantageous mass velocity-related activity effect is demonstrated when catalyst particles having this shape are disposed in a guard reactor having a smaller diameter than the diameter of the main reactor with which it is associated.

Abstract: An asphaltene-containing oil hydrodesulfurization process employing an upstream catalyst and a downstream catalyst in series. The downstream catalyst comprises supported Group VI and Group VIII metals together with a promoting amount of Group IV-B metal in the form of particles whose surface is shaped by multiple elongated alternating grooves and protrusions. The upstream catalyst comprises Group VI and Group VIII metals without promotion with Group IV-B metal in the form of particles which may or may not be similarly shaped. Beds of the downstream and upstream catalyst may be diposed in the same or in different reactors. The adaptation of the grooved particle configuration to the promoted catalyst composition provided the early development of a plateau-like aging curve which was not achieved by the adaptation of the grooved shape to a non-promoted catalyst.

Abstract: A catalytic asphaltene-containing oil hydrodesulfurization process employing a fixed catalyst bed comprising particles of supported Group VI and Group VIII metals, preferably together with a separate and downstream fixed catalyst bed comprising particles of Group VI and Group VIII metals together with a promoting amount of Group IV-B metal. The catalyst particles in both beds are in the form of elongated extrudates whose surface is provided with a plurality of alternating longitudinal grooves and protrusions. An advantageous mass velocity-related catalyst activity effect is achieved by recycling a portion of the desulfurized liquid product.

Abstract: An asphaltene-containing oil hydrodesulfurization process employing upstream and downstream reactors in series with an interstage flashing step. The catalyst in the downstream reactor comprises supported Group VI and Group VIII metals together with a promoting amount of Group IV-B metal. The particles of the catalyst in the downstream reactor are in the form of extrudates whose surface is provided with a plurality of alternating longitudinal grooves and protrusions. The catalyst in the upstream reactor comprises Group VI and Group VIII metals without promotion with Group IV-B metal and is in the form of particles whose surface may or may not have a similar grooved form. An advantageous mass velocity-related activity effect has been found when the downstream reactor has a diameter which is smaller than the diameter of the upstream reactor.

Abstract: An improved process for the hydrodesulfurization of hydrocarbons employing a catalyst comprising Group VI-B and Group VIII metals supported on a refractory oxide and promoted with a minor amount of titanium by contacting the refractory oxide with an aqueous solution of a titanium salt.

Abstract: A shutdown procedure for residual hydrocarbon hydrodesulfurization process which employs a catalyst comprising Group VI-B and Group VIII metals, in sulfided form, supported on a refractory oxide and promoted with a minor amount of titanium.