Patent ID: 7273958
Filing Date: 2007-09-25
Classification: C10G

Abstract:
1. A process for the production of an isomerate with a RON that is at least equal to 80, formed by at least 70% by weight of multibranched C 7 paraffins and containing less than 1% by weight of aromatic compounds, starting with a fraction comprising mostly of hydrocarbons with 7 carbon atoms, and containing paraffins, naphthenes, and aromatic compounds, said process comprising at least one isomerization unit, at least one unit for opening naphthene rings, and at least one separation unit, characterized in that said units are combined so as to recycle, to exhaustion, methyl cyclohexane, toluene, and normal paraffins and monobranched paraffins, and wherein at least one of the separation units is a distillation column fed by a mixture of different streams, at least one of which is obtained from fresh feedstock, and from which is extracted a) a top stream which, after optional supplemental separation, provides the produced isomerate, b) a side stream from a side draw-off plate that feeds, alone or in a mixture, a first isomerization unit having an inlet and an outlet, from which the normal paraffins and monobranched paraffins are converted to exhaustion, and c) a bottom stream, from which the toluene and the methyl cyclohexane contained in the fresh feedstock are recycled to exhaustion, wherein the isomerization effluent from the first isomerization unit, after stabilization, is sent to said distillation column on a plate located above the side draw-off plate, and wherein the fresh feedstock feeds the distillation column and wherein the ring opening unit is fed by the bottom stream from said column, part of the effluent from this ring opening unit being recycled to the inlet of the isomerization unit, mixed with the side draw-off stream obtained from said distillation column, and another part of the effluent from this ring opening unit being recycled, mixed with fresh feedstock, and fed to said distillation column.