Patent ID: 7847141

Claim:
A process for converting a hydrocarbons charge comprising paraffins, and linear and branched olefins comprising from 4 to 15 carbon atoms, said process comprising the following stages: a) a stage of membrane separation of the hydrocarbon charge, wherein the membrane separation stage comprises a membrane based on zeolites of MFI or ZSM-5 type, native or having been exchanged with H+, Na+, K+, Cs+, Ca+, Ba+ ions at ambient temperature to 400° C. and under conditions making it possible to produce a cut β containing paraffins and a majority of the linear olefins present in said charge, and a cut β containing paraffins and a majority of the branched olefins constituting a gasoline with a high octane number, greater than that of the charge, b) an oligomerization stage of treatment of the linear olefins contained in cut β under moderate oligomerization conditions comprising a pressure between 0.2 and 10 MPa, a ratio of charge volume flow rate to the catalyst volume (HSV) between 0.05 liter/liter.hour and 50 liter/liter.hour, and a temperature between 15° C. and 300° C., c) a stage of distillation separation of effluents from the oligomerization stage into at least two cuts a light cut δ, comprising hydrocarbons having a final boiling point below a temperature of between 150° C. and 200° C., and comprising the majority of the linear olefins and partly recycling said light cut δ to the oligomerization stage, and partly mixing said light cut δ with said cut γ containing paraffins and the majority of the branched olefins from the membrane stage, a heavy cut η, comprising hydrocarbons having an initial boiling point above a temperature of between 150° C. and 200° C., d) a stage of hydrogenation of the cut η under conditions for obtaining a gas oil with a cetane number of at least 35.