Transalkyation processes in the presence of sulfolane

Patent metadata

Field	Value
Publication number	US-11001544-B2
Application number	US-202015930215-A
Country	US
Kind code	B2
Filing date	May 12, 2020
Priority date	Jun 28, 2019
Publication date	May 11, 2021
Grant date	May 11, 2021

Abstract

Co-feeding sulfolane into a transalkylation reactor along with the aromatic hydrocarbon feed(s) can improve benzene purity of the benzene product stream produced from the transalkylation product mixture, especially at the beginning phase of a catalyst cycle.

First claim

What is claimed is:

1. A transalkylation process comprising:
introducing a C9+ aromatic feed, sulfolane, molecular hydrogen (H 2 ), and at least one of benzene and toluene into a transalkylation reactor having a transalkylation catalyst disposed therein, wherein at least a portion of the sulfolane is (i) introduced into the transalkylation reactor separately from the C9+ aromatic feed and the at least one of benzene and toluene and/or (ii) added into the C9+ aromatic feed and/or the at least one of benzene and toluene; and
contacting the C9+ aromatic feed, the sulfolane, and the at least one of benzene and toluene with the transalkylation catalyst for a first period of time under transalkylation conditions to produce a product mixture.

2. The process of claim 1 , wherein the first period of time is 1 day to 14 days.

3. The process of claim 1 , wherein the first period of time begins in proximity to a start of a catalyst cycle of the transalkylation catalyst.

4. The process of claim 1 , further comprising ceasing introducing sulfolane into the transalkylation reactor at the end of the first period of time.

5. The process of claim 4 , wherein the process further comprises:
supplying at least a portion of the product mixture into a distillation column without intermediate solvent extraction; and
obtaining a benzene product stream from the distillation column;

wherein the benzene product stream after ceasing introducing sulfolane into the transalkylation reactor at the end of the first period of time has a higher benzene purity is higher than a benzene product stream in a comparative process where sulfolane is not introduced into the transalkylation reactor in the first period of time.

6. The process of claim 1 , wherein the sulfolane is introduced into the transalkylation reactor at a quantity of 50 ppm to 400 ppm, based on the total weight of the C9+ aromatic feed, the sulfolane, and the at least one of benzene and toluene.

7. The process of claim 1 , wherein the sulfolane is fed into the transalkylation reactor at a quantity of 70 ppm to 200 ppm, based on the total weight of the C9+ aromatic feed, the sulfolane, and the at least one of benzene and toluene.

8. The process of claim 1 , wherein the C9+ aromatic feed consists essentially of C9+ aromatic hydrocarbons.

9. The process of claim 1 , wherein the at least one of benzene and toluene is toluene.

10. The process of claim 1 , further comprising:
supplying at least a portion of the product mixture into a distillation column without intermediate solvent extraction; and
obtaining a benzene product stream from the distillation column.

11. The process of claim 10 , wherein the benzene product stream comprises benzene at a concentration of at least 98.00 wt %, based on the total weight of the benzene product stream.

12. The process of claim 1 , wherein the transalkylation conditions comprise a feed inlet temperature of 200° C. to 550° C., a hydrogen to hydrocarbon molar ratio of 1.5 to 10, and an absolute pressure of 380 kPa to 4240 kPa.

13. The process of claim 1 , wherein the at least one of benzene and toluene is produced by a solvent extraction process using sulfolane as an extraction solvent.

14. The process of claim 13 , wherein at least a portion of the sulfolane is entrained in the at least one of benzene and toluene and is derived from the solvent extraction process.

15. The process of claim 1 , wherein at least a portion of the sulfolane is introduced into the transalkylation reactor separately from the C9+ aromatic feed and the at least one of benzene and toluene.

16. The process of claim 1 , wherein at least a portion of the sulfolane is added into the C9+ aromatic feed and/or the at least one of benzene and toluene.

17. A transalkylation process, the process comprising:
feeding a C9+ aromatic feed, molecular hydrogen (H 2 ), sulfolane and at least one of benzene and toluene into a transalkylation reactor having a transalkylation catalyst comprising a metal disposed therein, where the sulfolane is fed at a quantity from 50 ppm to 400 ppm, based on the total weight of the C9+ aromatic feed, the at least one of benzene and toluene, wherein at least a portion of the sulfolane is (i) introduced into the transalkylation reactor separately from the C9+ aromatic feed and the at least one of benzene and toluene and/or (ii) added into the C9+ aromatic feed and/or the at least one of benzene and toluene;
contacting the C9+ aromatic feed, the at least one of benzene and toluene, the molecular hydrogen, and the sulfolane with the transalkylation catalyst for a first period of time under transalkylation conditions to produce a product mixture rich in xylenes, wherein the transalkylation conditions comprise a feed inlet temperature from 200° C. to 550° C., a hydrogen to hydrocarbon molar ratio from 1.5 to 10, and an absolute pressure from 380 kPa to 4240 kPa; and
ceasing feeding the sulfolane to the transalkylation reactor at the end of the first period;
supplying at least a portion of the product mixture to a benzene distillation column without an intermediate solvent extraction process; and
obtaining a benzene product stream from the benzene distillation column.

18. The process of claim 17 , wherein the first period of time is from 1 to 14 days.

19. The process of claim 17 , wherein the first period of time begins in proximity to a start of a catalyst cycle of the transalkylation catalyst.

20. The process of claim 17 , wherein the sulfolane is fed into the transalkylation unit at a quantity from 70 ppm to 200 ppm, based on the total weight of the C9+ aromatic feed, the sulfolane, and the at least one of benzene and toluene.

21. The process of claim 17 , wherein the at least one of benzene and toluene is toluene.

22. The process of claim 17 , wherein the benzene product stream comprises benzene at a concentration of at least 99.00 wt %.

23. The process of claim 17 , the benzene purity of the benzene product stream after ceasing introducing sulfolane into the transalkylation reactor at the end of the first period of time is higher than a benzene product stream in a comparative process where sulfolane is not introduced into the transalkylation reactor in the first period of time.

24. The process of claim 16 , wherein the at least one of benzene and toluene is produced by a solvent extraction process using sulfolane as an extraction solvent.

25. The process of claim 24 , wherein at least a portion of the sulfolane is entrained in the at least one of benzene and toluene and is derived from the solvent extraction process.

26. The process of claim 17 , wherein at least a portion of the sulfolane is introduced into the transalkylation reactor separately from the C9+ aromatic feed and the at least one of benzene and toluene.

27. The process of claim 17 , wherein at least a portion of the sulfolane is added into the C9+ aromatic feed and/or the at least one of benzene and toluene.

Assignees

• Exxonmobil Chemical Patents Inc

Inventors

• Ramos Jesus A
• Tinger Robert G
• Podsiadlo Paul
• Detjen Todd E
• Keville Kathleen M

Classifications

• C07C6/126 Primary

  of more than one hydrocarbon · CPC title