Production of low sulfur gasoline

A process for desulfurizing gasoline containing olefins comprising the steps of:

• (a) introducing a gasoline stream comprising sulfur compounds and olefins into a fractionation zone to produce a low boiling fraction comprising mercaptan sulfur compounds and olefins, a mid boiling fraction comprising thiophene and olefins and a high boiling fraction comprising sulfur compounds and olefins;
• (b) contacting the low boiling fraction comprising mercaptan sulfur compounds and olefins with an aqueous alkaline solution to selectively remove at least a portion of the mercaptan sulfur compounds to produce a low boiling fraction having a reduced concentration of mercaptan sulfur compounds and comprising olefins;
• (c) contacting the mid boiling fraction comprising thiophene and olefins with a lean solvent to produce a raffinate stream having a reduced sulfur content relative to the mid boiling fraction and containing olefins and a rich-solvent stream enriched in thiophene;
• (d) separating the rich-solvent stream enriched in thiophene to produce a hydrocarbonaceous stream rich in thiophene and a lean solvent;
• and
• (e) reacting the hydrocarbonaceous stream rich in thiophene recovered in step (d) and the high boiling fraction comprising sulfur compounds and olefins recovered in step (a) in a hydrodesulfurization reaction zone to produce a hydrocarbonaceous stream having a reduced sulfur concentration.

A process for desulfurizing gasoline containing olefins comprising the steps of:

• (a) introducing a gasoline stream comprising sulfur compounds and olefins into a fractionation zone to produce a low boiling fraction comprising mercaptan sulfur compounds and olefins, a mid boiling fraction comprising thiophene and olefins, and a high boiling fraction comprising sulfur compounds and olefins;
• (b) contacting the low boiling fraction comprising mercaptan sulfur compounds and olefins with an aqueous alkaline solution to selectively remove at least a portion of the mercaptan sulfur compounds to produce a low boiling fraction having a reduced concentration of mercaptan sulfur compounds and comprising olefins;
• (c) introducing the mid boiling fraction comprising thiophene and olefins into an extractive distillation zone to produce a raffinate stream having a reduced sulfur content relative to the mid boiling fraction and containing olefins, and a hydrocarbonaceous stream rich in thiophene;
• and
• (d) reacting the hydrocarbonaceous stream rich in thiophene recovered in step (c) and the high boiling fraction comprising sulfur compounds and olefins recovered in step (a) in a hydrodesulfurization zone to produce a hydrocarbonaceous stream having a reduced sulfur concentration.