Desulphurization and hydrogenation of aromatic-containing hydrocarbon fractions

Claim 2

A process for the catalytic desulphurization of an aromatic-containing hydrocarbon fraction containing up to 50 ppm wt. sulphur without hydrogenation of more than 10 mol percent of the aromatic hydrocarbons, which process comprises passing said fraction in the liquid phase with hydrogen through a bed of catalyst comprising nickel supported on sepiolite, at a temperature in the range 75* to 250* C., a pressure in the range 100 to 2,000 psig, a liquid hourly space velocity (LHSV) in the range 0.1 to 5 v/v/hr and an inlet hydrogen:hydrocarbon molar ratio in the range 0.001:1 to 0.2:1, such that sulphur combines with the nickel but substantially no hydrogen sulphide is produced, the amount of hydrogen present being greater than the minimum necessary to prevent de-activation of the supported nickel catalyst but not more than the maximum Amount that would dissolve in the liquid fraction at the process temperature and pressure.

Claim 3

A process as claimed in claim 1 in which the aromatic-containing hydrocarbon fraction contains from 95 to 100 percent wt. aromatics, and boils within the range 15*-250* C, any other components present being saturated hydrocarbons.

Claim 4

A process as claimed in claim 1 in which the aromatic-containing hydrocarbon fraction is a straight-run distillate containing up to 25 percent wt. aromatics and boiling within the range 15*-250* C.

Claim 5

A process as claimed in claim 1, in which the aromatic hydrocarbon-containing fraction containing up to 50 ppm wt. sulphur is desulphurized to produce a fraction containing up to 2 ppm wt. sulphur, and this fraction is then hydrogenated in at least one hydrogenation stage with a catalyst comprising nickel supported on sepiolite.

Claim 6

A process for the desulphurization of an aromatic-containing hydrocarbon fraction containing more than 20 ppm wt. sulphur without hydrogenation of more than 10 mol percent of the aromatic hydrocarbons which comprises first contacting the fraction in a hydrodesulphurization stage with one or more oxides or sulphides of elements of Groups VIa and VIII of the Periodic Table in the presence of hydrogen, to reduce the sulphur content of the feedstock to about 50 ppm wt. sulphur, removing the hydrogen sulphide formed, and the fraction from which the H2S is removed being passed in the liquid phase with hydrogen through a bed of catalyst comprising nickel supported on sepiolite, at a temperature in the range 75* to 250* C., a pressure in the range 100 to 2,000 psig, a liquid hourly space velocity (LHSV) in the range 0.1 to 5 v/v/hr and an inlet hydrogen:hydrocarbon molar ratio in the range 0.001:1 to 0.2:1 such that the sulphur combines with the nickel but substantially no hydrogen sulphide is produced, the amount of hydrogen present being greater than the minimum necessary to prevent deactivation of the supported nickel catalyst but not more than the maximum amount that would dissolve in the liquid fraction at the process temperature and pressure.

Claim 7

A process for the desulphurization of an aromatic-containing hydrocarbon fraction containing more than 20 ppm wt. sulphur without hydrogenation of more than 10 mol percent of the aromatic hydrocarbons which comprises first contacting the fraction in a hydrodesulphurization stage with one or more oxides or sulphides of elements of Groups VIa and VIII of the Periodic Table in the presence of hydrogen, to reduce the sulphur content of the feedstock to about 50 ppm wt. sulphur, removing the hydrogen sulphide formed, and the fraction from which the H2S is removed being passed in the liquid phase with hydrogen through a bed of catalyst comprising nickel supported on sepiolite, at a temperature in the range 75* to 250* C., a pressure in the range 100 to 2,000 psig, a liquid hourly space velocity (LHSV) in the range 0.1 to 5 v/v/hr and an inlet hydrogen:hydrocarbon molar ratio in the range 0.001:1 to 0.2:1 such that the sulphur combines with the nickel but substantially no hydrogen sulphide is produced, the amount of hydrogen present being greater than the minimum necessary to prevent deactivation of the supported nickel catalyst but not more than the maximum amount that would dissolve in the liquid fraction at the process temperature and pressure.

Claim 8

A process as claimed in claim 1, in which the nickel on sepiolite catalyst used for the desulphurization and any subsequent hydrogenation stages contains from 1 to 50 percent wt. nickel.

Claim 9

A process as claimed in claim 6, in which the catalyst contains from 5 to 25 percent wt. nickel.

Claim 10

A process as claimed in claim 1, in which naphthenes are supplied to the desulphurization reaction when the aromatic content of the feedstock thereto is greater than 15 percent wt.

Claim 11

A process as claimed in claim 4, in which a hydrocarbon fraction containing more than 30 percent wt. aromatics is desulphurized to produce a fraction containing up to 2 ppm wt. sulphur and this latter fraction is hydrogenated in two stages, the first a main stage and the second a finishing stage, both of said stages using a catalyst comprising nickel supported on sepiolite, in which not less than 90 percent wt. and not more than 99 percent wt. of the aromatic hydrocarbons is hydrogenated in the first hydrogenation stage, with the hydrogenation reaction being substantially completed in the second hydrogenation stage and in which the temperature of the first hydrogenation stage is controlled by cooling.

Claim 12

A process as claimed in claim 9, in which the reaction conditions for the first and second hydrogenation stages are selected from the following: main hydrogenation reactor (first hydrogenation stage) Temperature 25 to 350*C Pressure 25 to 2000 psig Space velocity (fresh feed) 0.01 to 10.0 v/v/hr Product recycle ratio 0.1 to 10:1 Hydrogen recycle rate on total feed 50 to 5000 scf/brl finishing reaction (second hydrogenation stage) Temperature 77 to 662*F (25 to 350*C Pressure 75 to 2000 psig Space velocity 0.01 to 10.0 v/v/hr Hydrogen recycle rate 100 to 5000 scf/brl.

Claim 13

A process as claimed in claim 10, in which the reaction conditions for the first and second hydrogenation stages are selected from the following: main hydrogenation reactor (first hydrogenation stage) Temperature 122 to 572*F (50 to 300*C) Pressure 50 to 500 psig Space velocity (fresh feed) 0.5 to 5.0 v/v/hr Product recycle ratio 2.5:1 to 6:1 Hydrogen recycle rate on total feed 200 to 1000 scf/brl finishing reactor (second hydrogenation stage) Temperature 122 to 572*F (50 to 300*C) Pressure 50 to 500 psig Space velocity 0.5 to 5.0 v/v/hr Hydrogen recycle rate 500 to 2000 scf/brl.

Claim 14

A process as claimed in claim 9, in which the feedstock to the first hydrogenation stage is in mixed phase and the temperature of this stage is controlled by liquid recycle from the main reactor outlet or the finishing reactor outlet, and in which the finishing reactor outlet temperature is lower than the main reactor outlet temperature.

Claim 15

A process as claimed in claim 9, in which the flow of reactants in the main reactor is periodically reversed.

Claim 16

A process as claimed in claim 4, in which a hydrocarbon fraction containing not more than 30 percent wt. aromatics is desulphurized to produce a fraction containing up to 2 ppm wt. sulphur and this fraction is hydrogenated in one stage using conditions selected from the following: Temperature *C 25 to 350 Pressure psig 25 to 2000 Space velocity (LHSV) v/v/hr 0.01 to 10.0 Product recycle ratio 0.1 to 10:1 Hydrogen recycle rate on total feed scf/brl 50 to 5000.

Claim 17

A process as claimed in claim 14, in which the conditions are selected from the following: Temperature *C 50 to 300 Pressure psig 50 to 500 Space velocity (LHSV) v/v/hr 0.5 to 5.0 Product recycle ratio 1:1 to 6:1 Hydrogen recycle rate on total feed scf/brl 200 to 1000.