Catalytic gasoline desulfurization method having also an olefin selective removal function

Abstract

The present invention provides a catalytic gasoline desulfurization method having also an olefin selective removal function, which comprises: when a catalytic gasoline is pre-hydrotreated, cutting into a light fraction, a middle fraction and a heavy fraction; performing liquid-liquid extraction desulfurization treatment on the middle fraction to produce a sulfur-poor oil and a rich solvent containing sulfur-rich oil; the light fraction back-extracting the rich solvent, using C5 olefin therein to replace a macromolecular acyclic olefin in the sulfur-rich oil, so as to gather together C5 iso-olefins, cycloolefins, aromatic hydrocarbons and sulfides in the sulfur-rich oil; performing hydrogenation, olefin-reduction and desulfurization treatment on the heavy fraction together with the sulfur-rich oil removed from the back-extracted rich solvent to saturate the olefin therein; and finally, preparing together with the sulfur-poor oil to produce a full range gasoline. The sulfur-content of the catalytic gasoline produced by the method of the present invention can be reduced to 10 ppm or less, the olefin content of the catalytic gasoline can be reduced to 22%, the olefin is saturated by up to 8 percentage, and the RON loss of the full range gasoline is 1.5 or less, so that while reducing the olefin content of the catalytic gasoline, it ensures the less octane number loss, thereby satisfying the olefin-reduction requirements upgraded in the gasoline National VI Standard for ethanol-gasoline supply area enterprises.