High octane number gasolines and their production using a process associating hydro-isomerzation and separation

Abstract

The invention provides a high octane number gasoline pool comprises at least 2% of di-branched paraffins containing 7 carbon atoms, and a process for producing this gasoline pool by hydro-isomerising a feed constituted by a C5 to C8 cut which comprises at least one hydro-isomerisation section and at least one separation section, in which the hydro-isomerisation section comprises at least one reactor. The separation section comprises at least one unit and produces at least two streams: a first stream which is rich in di- and tri-branched paraffins, and possibly in naphthenes and aromatic compounds which is sent to the gasoline pool; and in a first version of the process, a second stream is produced which is rich in straight-chain and mono-branched paraffins which is recycled to the inlet of the hydro-isomerisation section, while in a second version of the process, a second flux is produced which is rich in straight-chain paraffins which is recycled to the inlet of a first hydro-isomerisation section and a third stream is produced which is rich in mono-branched paraffins which is recycled to the inlet of a second hydro-isomerisation section.

1 . A high octane number gasoline pool comprising a base from hydro-isomerisation of a C5 to C8 cut and comprising at least 2% of di-branched paraffins containing 7 carbon atoms.  
     
     
         2 . A gasoline pool according to  claim 1 , in which the content of di-branched paraffins containing 7 carbon atoms is at least 3%.  
     
     
         3 . A gasoline pool according to  claim 1 , in which the content of di-branched paraffins containing 7 carbon atoms is at least 4.5%.  
     
     
         4 . A gasoline pool according to any one of  claims 1  to  3 , in which the base from hydro-isomerisation originates from hydro-isomerisation of a C5 -C8 cut.  
     
     
         5 . A gasoline pool according to any one of  claims 1  to  3 , in which the base from hydro-isomerisation originates from hydro-isomerisation of a C6 -C8 cut.  
     
     
         6 . A process for producing a gasoline stock by hydro-isomerisation of a feed constituted by a C5 to C8 cut, comprising at least one hydro-isomerisation section and at least one separation section, in which the hydro-isomerisation section comprises at least one reactor, and the separation section comprises at least one unit and produces at least two streams: a first stream which is rich in di- and tri-branched paraffins, and possibly in naphthenes and aromatic compounds which is sent to the gasoline pool; and a second stream which is rich in straight-chain paraffins and mono-branched paraffins which is recycled to the inlet to the hydro-isomerisation section.  
     
     
         7 . A process for producing a gasoline stock by hydro-isomerisation of a feed constituted by a C5 to C8 cut, comprising at least two hydro-isomerisation section and at least one separation section, in which the separation section produces three streams: a first stream which is rich in di and tri-branched paraffins, and possibly in naphthenes and aromatic compounds which is sent to the gasoline pool; a second stream which is rich in straight-chain paraffins which is recycled to the inlet to the first hydro-isomerisation section; and a third stream which is rich in mono-branched paraffins which is recycled to the inlet to the second hydro-isomerisation section.  
     
     
         8 . A process according to  claim 7 , in which all of the effluent from the first hydro-isomerisation section traverses the second section.  
     
     
         9 . A process according to  claim 8 , in which the separation section is located downstream of the hydro-isomerisation sections, the feed is mixed with the straight-chain paraffins recycled from the separation section, the resulting mixture is sent to the first hydro-isomerisation section, the effluent leaving the first hydro-isomerisation section is mixed with the stream which is rich in mono-branched paraffins from the separation section, then the mixture is sent to the second hydro-isomerisation section, and the effluent from the latter section is sent to the separation section.  
     
     
         10 . A process according to  claim 8 , in which the separation section is located upstream of the hydro-isomerisation sections, the feed is mixed with the stream from the second hydro-isomerisation section, the resulting mixture is sent to the separation section, the effluent which is rich in straight-chain paraffins is sent to the first hydro-isomerisation section, the stream which is rich in mono-branched paraffins from the separation section is added to the effluent from the first hydro-isomerisation section, and the ensemble is sent to the second hydro-isomerisation section.  
     
     
         11 . A process according to  claim 7 , in which the effluents from the hydro-isomerisation sections are sent to at least one separation section.  
     
     
         12 . A process according to any one of  claims 6  to  11 , in which the separation section is constituted by at least two distinct units to carry out two different types of separation.  
     
     
         13 . A process according to any one of  claims 6  to  12 , in which the separation section comprises one or more sections operating by adsorption.  
     
     
         14 . A process according to any one of  claims 6  to  12 , in which the separation section comprises one or more sections operating by permeation.  
     
     
         15 . A process according to any one of  claims 6  to  12 , in which the separation section comprises at least one unit operating by adsorption and at least one unit operating by permeation.  
     
     
         16 . A process according to any one of  claims 6  to  15 , in which at least one light fraction is separated by distillation upstream or downstream of the hydro-isomerisation and/or separation sections.  
     
     
         17 . A process according to any one of  claims 6  to  15 , in which the feed contains the C5 cut and at least one deisopentaniser and/or at least one depentaniser are located upstream or downstream of the hydro-isomerisation and/or separation sections.  
     
     
         18 . A process according to any one of  claims 6  to  15 , in which the feed contains a C6 cut but contains no C5, and at least one deisohexaniser is located upstream or downstream of the hydro-isomerisation and/or separation sections.  
     
     
         19 . A process according to any one of  claims 16  to  18 , in which the light fraction or the isopentane and/or the pentane and/or a mixture of the two, or the hexane, act as an eluent or a flushing gas for the adsorption or permeation separation processes respectively.  
     
     
         20 . A process according to any one of  claims 6  to  18 , in which butane and/or isobutane is used as an eluent or a flushing gas for the adsorption or permeation separation processes respectively.  
     
     
         21 . A process according to  claim 17 , in which the isopentane is sent to the gasoline pool.  
     
     
         22 . A process according to any one of  claims 6  to  21 ; in which the feed comprises at least 12 mole % of hydrocarbons containing at least 7 carbon atoms.  
     
     
         23 . A process according to any one of  claims 6  to  21 , in which the feed comprises at least 15 mole % of hydrocarbons containing at least 7 carbon atoms.  
     
     
         24 . A process according to any one of  claims 6  to  23 , in which hydro-isomerisation is carried out at temperatures in the range 25° C. to 450° C., at a pressure in the range 0.01 to 7 MPa, at a space velocity, measured in kg of feed per kg of catalyst per hour, in the range 0.5 to 2, and with an H2/hydrocarbons molar ratio in the range 0.01 to 50.  
     
     
         25 . A process according to any one of  claims 6  to  24 , in which separation is carried out at temperatures in the range 50° C. to 450° C. and at a pressure in the range 0.01 to 7 MPa.