FIELD: material hydrodesulfurization.
SUBSTANCE: invention relates to a method for hydrodesulfurization of an olefinic naphtha feedstock while maintaining a significant amount of olefins, said feedstock having a boiling point T95 below 250°C and containing at least 50 wt. ppm organically bound sulfur and 5% to 60% olefins and diolefins. The method includes: (a) selective hydrogenation of diolefins under reaction conditions comprising a temperature of 100°C to 200°C, a pressure of 5 bar to 50 bar, and a gas to oil ratio of 2 nm3/m3 to 25 nm3/m3 to convert at least 90% of diolefins to alkanes or monoolefins, with provision of pretreated feedstock, (b) hydrodesulfurizing the pretreated feedstock in a sulfur removal step in the presence of hydrogen and a hydrodesulfurization catalyst under hydrodesulfurization reaction conditions comprising a temperature of 200°C to 350°C, a pressure of 2 bar to 50 bar, and a gas to oil ratio of 750 nm3/m3 to 2500 nm3/m3 to convert at least 50% of organically bound sulfur to hydrogen sulfide and obtain a desulfurized product stream containing from 0 wt. ppm up to 50 wt. ppm of organically bound sulfur, c) separating the pretreated feedstock into at least a heavy naphtha stream and a light naphtha stream according to the boiling point, d) directing said heavy naphtha stream as a feedstock for said hydrodesulfurization step to provide a desulfurized product stream, f) combining said stream a desulfurized product and said light naphtha stream to form a final product stream.
EFFECT: reduces sulfur removal while minimizing olefin hydrogenation and octane reduction.
13 cl, 4 dwg, 6 tbl, 4 ex
