Production of high-octane gasoline by paraffin isomerization comprises separating isopentane and dibranched six carbon paraffins from n-pentane in membrane separation unit

摘要

The production of high-octane gasoline from a C 5-C 7hydrocarbon feed comprising a major amount of n-paraffins, isoparaffins and naphthenes and a minor amount of aromatics comprises introducing the feed into an isomerization unit, removing light hydrocarbons in a stabilizer column, separating n-pentane, isopentane and dibranched C 6paraffins in a deisohexanizer column and separating isopentane and dibranched C 6paraffins in a membrane separation unit. The production of high-octane gasoline from a C 5-C 7hydrocarbon feed comprising a major amount of n-paraffins, isoparaffins and naphthenes and a minor amount of aromatics comprises optionally removing part of the branched paraffins from the feed, introducing the feed into an isomerization unit (1), recovering an effluent (C) enriched in multibranched paraffins, passing effluent (C) to a stabilizer column (2) to produce a light overhead gas stream (D) comprising C 5-hydrocarbons and a bottoms stream (E) which is passed to a deisohexanizer column (3), withdrawing an overhead stream (H) comprising n-pentane, isopentane and dibranched C 6paraffins, withdrawing a side or bottoms stream (G) comprising n-hexane and monobranched C 6paraffins, which is recycled to the isomerization unit and/or passed to a petrochemical naphtha storage and blending zone, optionally withdrawing a bottoms stream (F) comprising branched C 7paraffins, cyclohexane and naphthenes, passing stream (H) to a membrane separation unit (4) to produce a retentate (J) comprising isopentane and dibranched C 6paraffins, which is passed to a gasoline storage and blending zone, and a permeate (I) comprising n-pentane which is recycled to the isomerization unit and/or passed to a petrochemical naphtha storage and blending zone.