Process for reducing unsaturated hydrocarbons in aromatic fraction through selective hydrogenation

Patent metadata

Field	Value
Publication number	US-11802248-B2
Application number	US-202117460843-A
Country	US
Kind code	B2
Filing date	Aug 30, 2021
Priority date	Sep 7, 2020
Publication date	Oct 31, 2023
Grant date	Oct 31, 2023

Abstract

Disclosed are a process and system that are capable of performing selective hydrogenation on aromatic fractions by configuring a catalyst bed through staged loading of a plurality of hydrogenation catalysts with different catalytic properties, or configuring a catalyst system in which a plurality of hydrogenation catalysts are arranged using a plurality of reactors in such a way as to be equivalent with the staged loading, and as a result, are capable of suppressing aromatic loss while improving the selective removal of unsaturated hydrocarbons in the aromatic fraction and durability compared to the case of using a single catalyst.

First claim

What is claimed is:

1. A method of removing unsaturated hydrocarbons in an aromatic fraction, which comprises:
a) providing an aromatic hydrocarbon-containing feedstock having a bromine index of 30 to 15,000, and
b) bringing the feedstock into contact with a multi-stage catalyst bed comprising at least one first catalyst bed and a second catalyst bed disposed downstream of the at least one first catalyst bed in a reactor and performing hydrogenation in a liquid phase reaction or three-phase reaction under supply of hydrogen to form an aromatic hydrocarbon-containing product having a reduced bromine index,
wherein,
the at least one first catalyst bed comprises a support containing inorganic oxide, and at least one active metal selected from the group consisting of Ni, Pd, Pt, Ru, Re, Co, Mo, Co—Mo, Ni—Mo, and Ni—W, in which, among the active metals, each of Re, Co, Mo, and Co—Mo is a reduced or sulfide form, and each of Ni, Pd, Pt, Ru, Ni—Mo and Ni—W is a sulfide form,
the second catalyst bed comprises a support containing inorganic oxide, and Ni—Mo and/or Ni—W in a reduced form as an active metal,
the at least one first catalyst bed exhibits a less activity for aromatic loss than the second catalyst bed, and
hydrogen supplied on the at least one first catalyst bed is consumed as the hydrogenation proceeds such that hydrogen is supplied on the second catalyst bed in an amount lower than on the at least one first catalyst bed, and
a temperature of the hydrogenation is determined within a range from room temperature to less than 230° C.

2. A method of removing unsaturated hydrocarbons in an aromatic fraction, which comprises:
a) providing an aromatic hydrocarbon-containing feedstock having a bromine index of 30 to 15,000, and
b) transferring the feedstock to a multi-stage hydrogenation unit comprising a first reaction unit containing at least one first catalyst and a second reaction unit containing a second catalyst and communicating with the first reaction unit at the downstream of the first reaction unit and performing hydrogenation in a liquid phase reaction or three-phase reaction under supply of hydrogen to form an aromatic hydrocarbon-containing product having a reduced bromine index,
wherein,
the at least one first catalyst comprises a support containing inorganic oxide, and at least one active metal selected from the group consisting of Ni, Pd, Pt, Ru, Re, Co, Mo, Co—Mo, Ni—Mo, and Ni—W, in which, among the active metals, each of Re, Co, Mo, and Co—Mo is a reduced or sulfide form, and each of Ni, Pd, Pt, Ru, Ni—Mo and Ni—W is a sulfide form,
the second catalyst comprises a support containing inorganic oxide, and Ni—Mo and/or Ni—W in a reduced form as an active metal,
the at least one first catalyst exhibits a less activity for aromatic loss than the second catalyst, and
hydrogen supplied to the first reaction unit is consumed as the hydrogenation proceeds such that hydrogen is supplied to the second reaction unit in an amount lower than the first reaction unit, and
a temperature of the hydrogenation is determined within a range from room temperature to less than 230° C.

3. The method according to claim 1 , wherein at least 30% by weight of unsaturated hydrocarbons in the aromatic hydrocarbon-containing feedstock is removed by hydrogenation.

4. The method according to claim 1 , wherein an aromatic loss in the aromatic hydrocarbon-containing product is less than 1% by weight relative to the aromatic hydrocarbon-containing feedstock.

5. The method according to claim 2 , wherein the first reaction unit comprises a plurality of reactors connected in series.

6. The method according to claim 1 , wherein an amount of hydrogen supplied to the hydrogenation is within a range of at least 0.5 moles with respect to 1 mole of unsaturated hydrocarbons present in the feedstock.

7. The method according to claim 1 , wherein
a pressure for the hydrogenation is determined within a range of 3 to 70 bar.

8. The method according to claim 1 , wherein the inorganic oxide comprises at least one selected from the group consisting of alumina, silica, silica-alumina, aluminum phosphate, zirconia, titania, bentonite, kaolin, clinoptilolite and montmorillonite.

9. The method according to claim 1 , wherein a content of the active metal in the first catalyst ranges from 0.5 to 40% by weight, and
a content of the active metal in the second catalyst ranges from 2 to 40% by weight.

10. The method according to claim 1 , wherein the aromatic hydrocarbon-containing feedstock has a boiling point in a range of 35 to 300° C.

11. The method according to claim 1 , wherein the aromatic hydrocarbon-containing feedstock is a C5+ reformate.

12. The method according to claim 1 , wherein an amount of the at least one first catalyst bed is in a range of 10 to 90%, based on the total volume of the at least one first catalyst bed and the second catalyst bed.

13. The method according to claim 1 , wherein the aromatic hydrocarbon-containing feedstock contains C6 to C18 alkyl aromatic hydrocarbons.

14. The method according to claim 13 , wherein the aromatic hydrocarbon-containing feedstock contains benzene, toluene, xylene, and/or C9+ aromatics.

15. The method according to claim 1 , wherein an aromatic content of the aromatic hydrocarbon-containing feedstock is in a range of at least 50% by weight.

16. The method according to claim 1 , wherein the support in each of the at least one first catalyst bed and the second catalyst bed is in a shape of cylinder, granule, pellet, tablet or sphere.

17. The method according to claim 1 , wherein the support in each of the at least one first catalyst bed and the second catalyst bed exhibits an apparent density of 0.3 to 1.2 g/cc, an average pore diameter of 3 to 1,000 nm, and a specific surface area (BET) of 10 to 1,000 m 2 /g.

18. The method according to claim 7 , wherein a space velocity (LHSV) of the aromatic-containing feedstock is controlled within a range of 0.3 to 30 hr −1 .

19. The method according to claim 1 , which further comprises subjecting the aromatic hydrocarbon-containing product having a reduced bromine index to benzene, toluene or xylene product separation, transalkylation, or xylene isomerization.

Assignees

• Sk Innovation Co Ltd
• Sk Geo Centric Co Ltd

Inventors

• Lee Sang Il
• Lee Ji Hoon
• Cheon Young Eun

Classifications

• C10G45/38 Primary

  in combination with chromium, molybdenum or tungsten metals, or compounds thereof · CPC title

• B01J19/245

  placed in series · CPC title

• B01J23/28

  Molybdenum · CPC title

• B01J23/882

  and cobalt · CPC title

• B01J23/883

  and nickel · CPC title