Process for the dearomatization of petroleum cuts
A process for dearomatization of a petroleum cut produces a dearomatized hydrocarbon-containing fluid with a sulphur content less than or equal to 5 ppm and a content of aromatic compounds less than or equal to 300 ppm, the hydrocarbon-containing fluid has a boiling point between 100 and 400° C. according to the standard ASTM D-86 and a distillation range defined by the difference between the Initial Boiling Point (IBP) and the Final Boiling Point (FBP) determined by the standard ASTM D-86 not exceeding 80° C. The process includes at least one dearomatization cycle utilizing a mixture of the petroleum cut with one or more inert and light diluents having a distillation range not exceeding 80° C.
1. A process for dearomatization of a petroleum cut comprising producing a dearomatized hydrocarbon-containing fluid having a sulphur content less than or equal to 5 ppm and having a content of aromatic compounds less than or equal to 300 ppm, the hydrocarbon-containing fluid having a boiling point comprised between 100 and 400° C. according to the standard ASTM D-86 and a distillation range defined by the difference between an Initial Boiling Point (IBP) and a Final Boiling Point (FBP) determined in accordance with the standard ASTM D-86 not exceeding 80° C., the process further comprising at least one dearomatization cycle utilizing a mixture of the petroleum cut with one or more inert and light diluent, wherein:
the petroleum cut is an ultra-low sulphur diesel obtained by a hydrodesulphurization of straight run gasoil cuts from atmospheric distillation, the petroleum cut being devoid of hydrocracked vacuum gasoil (HCVGO),
the one or more inert and light diluent has a boiling point in the range of 141 to 164° C. according to the standard ASTM D-86, has a distillation range not exceeding 80° C., has a content of aromatics less than 50 ppm measured by UV spectrometry, has a sulphur content less than 2 ppm according to the standard ASTM D-5453, and consists of a majority of isoparaffins and a minority of normal paraffins, wherein a mass ratio between the petroleum cut and the one or more inert and light diluent is comprised between 30/70 and 50/50, and
the dearomatization is a catalytic hydrogenation carried out at a temperature between 160 and 200° C. and at a pressure between 100 and 160 bar in the presence of a nickel-based catalyst.
2. The process according to claim 1 , wherein the Final Boiling Point of the one or more inert and light diluent is less than the Initial Boiling Point of the petroleum cut to be treated by at least 10° C.
3. The process according to claim 1 , wherein the one or more inert and light diluent contains more than 90% by weight of isoparaffins.
4. The process according to claim 1 , wherein the one or more inert and light diluent has a content of benzene compounds less than 10 ppm by weight according to the standard ASTM D-6229.
5. The process according to claim 1 , wherein the one or more inert and light diluent has a kinematic viscosity at 20° C. comprised between 0.75 and 2.04 mm 2 /s according to the standard EN ISO 3104.
6. The process according to claim 1 , wherein the one or more inert and light diluent is a hydrocarbon-containing cut obtained by atmospheric distillation, vacuum distillation, catalytic cracking, oligomerization and/or hydrogenation of crude oil.
7. The process according to claim 1 , wherein the one or more inert and light diluent is a hydrocarbon-containing cut obtained by the oligomerization and hydrogenation of a propylene cut or a butylene cut.
8. The process according to claim 1 , wherein the one or more inert and light diluent is a gasoline cut or a kerosene cut originating from the oligomerization and hydrogenation of a propylene cut or a butylene cut.
9. The process according to claim 1 , wherein the petroleum cut contains a sulphur content less than 15 ppm according to the standard EN ISO 20846.
10. A method for improving hydrogenation yield and reducing deactivation of a hydrogenation catalyst, said method comprising the steps of:
a) mixing an inert and light diluent having a boiling point in the range of 141 to 164° C. according to the standard ASTM D-86, a distillation range not exceeding 80° C., having a content of aromatics less than 50 ppm measured by UV spectrometry, having a sulphur content less than 2 ppm according to the standard ASTM D-5453 and consisting of a majority of isoparaffins and a minority of normal paraffins, with a petroleum cut, wherein the petroleum cut is an ultra-low sulphur diesel obtained by a hydrodesulphurization of straight run gasoil cuts from atmospheric distillation, the petroleum cut being devoid of hydrocracked vacuum gasoil (HCVGO), wherein a mass ratio between the petroleum cut and the one or more inert and light diluent is comprised between 30/70 and 50/50;
b) subjecting the mixture to at least one dearomatization cycle, wherein the dearomatization is a catalytic hydrogenation carried out at a temperature between 160 and 200° C. and at a pressure between 100 and 160 bar in the presence of a nickel-based catalyst.
11. The process according to claim 1 , wherein the one or more inert and light diluent is constituted by branched C7-C14 alkanes.
12. The process according to claim 11 , wherein the one or more inert and light diluent is constituted by branched C9-C12 alkanes.
13. The process according to claim 3 , wherein the one or more inert and light diluent contains more than 99% by weight of isoparaffins.
14. The process according to claim 1 , wherein the one or more inert diluent is constituted by a majority of C10-C12 isoparaffins.