High performance monolith treater for gasoline upgrade

Abstract

A method of increasing the selective desulfurization of naphtha feed streams that includes: combining a naphtha feed stream with a hydrogen containing gas to form a combined feed stream and reacting the combined feed stream over a monolithic honeycomb catalyst bed containing hydrodesulfurization catalyst components to give a desulfurized naphtha. In conducting such an illustrative embodiment, the percent desulfurization of the naphtha is preferably greater than about 50% and the percent olefin hydrogenation of the naphtha is preferably less than about 50%. The monolithic honeycomb catalyst bed of one alternative and illustrative embodiment preferably has a channel density of about 25 to 1600 cells per square inch; a channel size from about 0.1 to 10 mm; and a channel wall thickness of about 0.01 to about 2.0 mm. The illustrative method should be carried out such that the octane number (R+M/2) of the naphtha feed stream is reduced by no more than 3.0 at 95% desulfurization and preferably no more than 1.5. The hydrodesulfurization catalyst components include a powdered refractory oxide and transition metal catalyst compounds. Alternatively the hydrodesulfurization catalyst components may be impregnated into the monolithic honeycomb catalyst bed itself. Preferable hydrodesulfurization catalyst components include a Group VIII metal containing compound and a Group VIB metal containing compound. Alternatively the hydrodesulfurization catalyst components may further include a phosphorous promoter.