Hydrogen recycle and hydrogen chloride recovery in an alkylation process

• US 9,233,316 B2
• Filed: 07/31/2012
• Issued: 01/12/2016
• Est. Priority Date: 07/31/2012
• Status: Active Grant

• Current Assignee: Chevron USA Incorporated (Chevron Corp.)
• Original Assignee: Chevron USA Incorporated (Chevron Corp.)
• Inventors: Timken, Hye Kyung Cho, Cleverdon, Robert Fletcher, Chang, Bong-Kyu, Mohr, Donald Henry, Phillips, Christine Marie
• Primary Examiner(s): Bullock, In Suk
• Assistant Examiner(s): Jeong, Youngsul
• Application Number:
  US13/563,385
• Publication Number:
  US 20140039231A1
• Time in Patent Office: 1,260 Days
• Field of Search: 585/251, 585/721
• US Class Current: 1/1
• CPC Class Codes: B01D 3/009 in combination with chemical reactions
• CPC Class Codes: B01J 2231/32 Addition reactions to C=C or C-C triple bonds
• CPC Class Codes: B01J 31/0277 comprising ionic liquids, as components in catalyst systems or catalysts per se, the ionic liquid compounds being used in the molten state at the respective reaction temperature
• CPC Class Codes: B01J 31/0281 the nitrogen being a ring member
• CPC Class Codes: C07C 2/58 Catalytic processes
• CPC Class Codes: C07C 5/02 by hydrogenation simultaneous hydrogenation and dehydrogenation C07C5/52
• CPC Class Codes: C10G 29/205 by reaction with hydrocarbons added to the hydrocarbon oil
• CPC Class Codes: Y02P 20/584 Recycling of catalysts

Abstract

We provide an alkylation process, comprising: separating and recycling a hydrogen gas and a hydrogen chloride from an offgas of a hydrogenation reactor; wherein the hydrogen gas is recycled to the hydrogenation reactor; and wherein the hydrogen chloride is recycled to an alkylation reactor. We also provide an alkylation process unit for performing this process.

Claims

1. An alkylation process, comprising:

alkylating hydrocarbon reactants in an alkylation reactor (300) in the presence of an alkylation catalyst comprising an ionic liquid catalyst; and

separating an offgas (50) from a hydrogenation reactor (100) wherein the hydrogenation reactor is used to regenerate a used ionic liquid catalyst;

separating a purified hydrogen gas stream and a hydrogen chloride from the offgas, and

recycling the purified hydrogen gas stream and the hydrogen chloride,

wherein the purified hydrogen gas stream is recycled to the hydrogenation reactor (100),

wherein the hydrogen chloride is recycled to the alkylation reactor (300),

wherein the hydrogen chloride is separated from the offgas (50) using a hydrocarbon extraction solvent (25) comprising the hydrocarbon reactants,

and wherein the purified hydrogen gas stream has a reduced amount of the hydrogen chloride that is less than or equal to 20% of the hydrogen chloride contained in the offgas (50).

2. The alkylation process of claim 1, wherein the hydrocarbon extraction solvent (25) comprises an isomerized olefin.

3. The alkylation process of claim 1, wherein the alkylation reactor (300) uses an alkylation catalyst comprising a chloride.

4. The alkylation process of claim 3, wherein the alkylation catalyst is the ionic liquid catalyst.

5. The alkylation process of claim 4, wherein a hydrocarbon extraction solvent (25) is fed into a stream selected from the group consisting of a hydrogenated effluent (10), the offgas (50) of the hydrogenation reactor (100) that was separated in a separator (400), and a combination thereof.

6. The alkylation process of claim 5, wherein the hydrocarbon extraction solvent (25) is fed at a vol/vol ratio of the hydrocarbon extraction solvent (25) to the ionic liquid catalyst from 1.0 to 100.

7. The alkylation process of claim 5, wherein a vol/vol ratio of the hydrocarbon extraction solvent (25) to the ionic liquid catalyst is selected to provide a level of hydrogen chloride less than 600 wppm in a gas fraction comprising the purified hydrogen gas stream.

8. The alkylation process of claim 5, wherein a vol/vol ratio of the hydrocarbon extraction solvent (25) to the ionic liquid catalyst is selected to provide at least 85% of the hydrogen chloride produced in the hydrogenation reactor (100) is recovered and recycled to the alkylation reactor (300).

9. The alkylation process of claim 1, wherein the separating the purified hydrogen gas stream and the hydrogen chloride is done in a fractionation unit (200) that is a distillation column.

10. The alkylation process of claim 1, wherein a hydrocarbon extraction solvent (25) is fed into a fractionation unit (200), used for the separating, at a location above where the offgas (50) of the hydrogenation reactor (100) is fed into the fractionation unit (200).

11. The alkylation process of claim 1, wherein the hydrocarbon extraction solvent (25) comprises an olefin and an isoparaffin to be alkylated to make an alkylate gasoline blending component.

12. The alkylation process of claim 11, wherein the olefin contains greater than 10 wt % 2-butene and the isoparaffin is isobutane.

13. The alkylation process of claim 1, additionally comprising separating an extracted conjunct polymer naphtha (45) from the effluent (10) of the hydrogenation reactor (100) and blending the extracted conjunct polymer naphtha (45) into an alkylate gasoline.

14. The alkylation process of claim 1, wherein the hydrocarbon extraction solvent (25) comprises isobutane, 2-butene, or mixtures thereof.

15. The alkylation process of claim 1, additionally comprising compressing the purified hydrogen gas stream before recycling the purified hydrogen gas stream to the hydrogenation reactor.

16. The alkylation process of claim 15, wherein conventional compressor equipment and piping are used for the compressing.

17. The alkylation process of claim 13, wherein the extracted conjunct polymer naphtha (45) has a final boiling point less than 246°

C.

18. The alkylation process of claim 1, wherein the reduced amount of the hydrogen chloride is from less than 1% to less than 10% of the hydrogen chloride contained in the offgas (50).

19. The alkylation process of claim 1, wherein the hydrocarbon extraction solvent (25) is fed to a fractionation unit or to a separator that is located between the hydrogenation reactor and the fractionation unit.

20. The alkylation process of claim 1, wherein the hydrogen chloride that is recycled to the hydrogenation reactor (100) is mixed with a recycled stream comprising a mixture of gaseous hydrogen chloride and a propane.