Method of removing oxygenate contaminants from an olefin stream

• US 6,838,587 B2
• Filed: 04/19/2002
• Issued: 01/04/2005
• Est. Priority Date: 04/19/2002
• Status: Expired due to Term

• Current Assignee: UOP Llc (Honeywell International Inc.)
• Original Assignee: ExxonMobil Chemical Patents Inc. (Exxon Mobil Corporation)
• Inventors: Lattner, James R., Lumgair, David R. Jr.
• Primary Examiner(s): Griffin, Walter D.
• Assistant Examiner(s): Nguyen, Tam M.
• Application Number:
  US10/126,390
• Publication Number:
  US 20030199722A1
• Time in Patent Office: 991 Days
• Field of Search: 585/807, 585/809, 585/833, 585/864, 585/639
• US Class Current: 585/807
• CPC Class Codes: C07C 11/02 Alkenes
• CPC Class Codes: C07C 7/005 Processes comprising at least two steps in series
• CPC Class Codes: C07C 7/08 by extractive distillation

Abstract

This invention is directed to a method of removing acetaldehyde, CO₂ and/or water from an ethylene and/or propylene containing stream. In this invention, acetaldehyde and C₄+ olefins are substantially removed from the ethylene and/or propylene containing stream. The stream is then acid gas treated. The ethylene and/or propylene streams which are separated and recovered according to this invention can be further processed, for example, to make polymers such as polyethylene and polypropylene.

Claims

1. A method of treating an ethylene and/or propylene containing stream, comprising:

providing an olefin stream containing ethylene, propylene, C₄+ olefins and acetaldehyde;

separating the olefin stream into a first fraction and a second fraction, wherein the first fraction comprises at least a majority of the ethylene and/or propylene present in the olefin stream, and the second fraction comprises at least a majority of the C₄+ olefins and acetaldehyde present in the olefin stream; and

acid gas treating the first fraction.

2. The method of claim 1, wherein the provided olefin stream further comprises CO₂, and the first fraction further contains at least a majority of the CO₂ in the provided olefin stream.

3. The method of claim 2, wherein acid gas treating the first fraction comprises contacting the first fraction with caustic.

4. The method of claim 1, wherein the second fraction is comprised of at least 5 wt % C₄+ olefin, based on the total weight of the second fraction.

5. The method of claim 1, wherein the olefin stream is separated by distillation.

6. The method of claim 2, wherein the distillation is extractive distillation using an extractant.

7. The method of claim 6, wherein the extractant is a polar composition having an average boiling point of at least 100°

F. (38°

C.) at 1 atm.

8. The method of claim 7, wherein the extractant is methanol.

9. The method of claim 1, wherein the first fraction comprises at least a majority of the ethylene present in the olefin stream, and the second fraction comprises at least a majority of the propylene present in the olefin stream.

10. The method of claim 1, wherein the first fraction comprises at least a majority of the ethylene and propylene present in the olefin stream.

11. The method of claim 1, wherein the second fraction comprises at least 1,000 wppm acetaldehyde.

12. The method of claim 1, wherein the provided olefin stream further contains propane, and the first fraction comprises at least a majority of the ethylene, propylene and propane present in the olefin stream.

13. The method of claim 1, wherein the provided olefin stream further contains propane, the first fraction comprises at least a majority of the ethylene and propylene present in the olefin stream, and the second fraction further comprises at least a majority of the propane present in the olefin stream.

14. A method of treating an ethylene and/or propylene containing stream made from an oxygenate to olefin process comprising:

contacting oxygenate with a molecular sieve catalyst to form an olefin stream comprising ethylene, propylene, and acetaldehyde;

separating the olefin stream into a first fraction and a second fraction, wherein the first fraction comprises at least a majority of the ethylene and/or propylene present in the olefin stream, and the second fraction comprises at least a majority of the acetaldehyde present in the olefin stream; and

acid gas treating the first fraction.

15. The method of claim 14, wherein the olefin stream further comprises CO₂, and the first fraction further contains at least a majority of the CO₂ in the provided olefin stream.

16. The method of claim 15, wherein acid gas treating the first fraction comprises contacting the first fraction with caustic.

17. The method of claim 14, wherein the olefin stream further comprises C₄+ olefins, and the second fraction further comprises at least 5 wt % C₄+ olefin, based on the total weight of the second fraction.

18. The method of claim 14, wherein the olefin stream is separated by distillation.

19. The method of claim 18, wherein the distillation is extractive distillation using an extractant.

20. The method of claim 19, wherein the extractant is a polar composition having an average boiling point of at least 100°

F. (38°

C.) at 1 atm.

21. The method of claim 20, wherein the extractant is methanol.

22. The method of claim 14, wherein the first fraction comprises at least a majority of the ethylene present in the olefin stream, and the second fraction comprises at least a majority of the propylene present in the olefin stream.

23. The method of claim 14, wherein the first fraction comprises at least a majority of the ethylene and propylene present in the olefin stream.

24. The method of claim 14, wherein the second fraction comprises at least 1,000 wppm acetaldehyde.

25. The method of claim 14, wherein the olefin stream further contains propane, and the first fraction comprises at least a majority of the ethylene, propylene and propane present in the olefin stream.

26. The method of claim 14, wherein the olefin stream further contains propane, the first fraction comprises at least a majority of the ethylene and propylene present in the olefin stream, and the second fraction comprises at least a majority of the propane present in the olefin stream.

27. A method of treating an ethylene containing stream, comprising:

providing an olefin stream containing ethylene, propylene, C₄+ olefins and acetaldehyde;

separating the olefin stream into a first fraction and a second fraction, wherein the first fraction comprises at least a majority of the ethylene present in the olefin stream and the second fraction comprises at least a majority of the propylene, C₄+ olefin and acetaldehyde present in the olefin stream; and

acid gas treating the first fraction.

28. The method of claim 27, wherein the provided olefin stream further comprises CO₂, and the first fraction further contains at least a majority of the CO₂ in the provided olefin stream.

29. The method of claim 28, wherein acid gas treating the first fraction comprises contacting the first fraction with caustic.

30. The method of claim 29, wherein the olefin stream is separated by distillation.

31. The method of claim 30, wherein the distillation is extractive distillation using an extractant.

32. The method of claim 31, wherein the extractant is a polar composition having an average boiling point of at least 100°

F. (38°

C.) at 1 atm.

33. The method of claim 32, wherein the extractant is methanol.

34. The method of claim 27, wherein ethylene in the first fraction is polymerized to form polyethylene.

35. A method of treating an ethylene and propylene containing stream comprising:

providing an olefin stream containing ethylene, propylene, C₄+ olefins and acetaldehyde;

separating the olefin stream into an first fraction and a second fraction, wherein the first fraction comprises at least a majority of the ethylene and propylene present in the olefin stream, and the second fraction comprises at least a majority of the C₄+ olefins and acetaldehyde present in the olefin stream; and

acid gas treating the first fraction.

36. The method of claim 35, wherein the provided olefin stream further comprises CO₂, and the first fraction further contains at least a majority of the CO₂ in the provided olefin stream.

37. The method of claim 36, wherein acid gas treating the first fraction comprises contacting the first fraction with caustic.

38. The method of claim 35, wherein the olefin stream is separated by distillation.

39. The method of claim 38, wherein the distillation is extractive distillation using an extractant.

40. The method of claim 39, wherein the extractant is a polar composition having an average boiling point of at least 100°

F. (38°

C.) at 1 atm.

41. The method of claim 40, wherein the extractant is methanol.

42. The method of claim 35, wherein the ethylene and propylene in the first fraction are separated before or after acid gas treatment, and polymerized to form polyethylene and polypropylene.

43. The method of claim 35, wherein the second fraction comprises at least 1,000 wppm acetaldehyde.

44. The method of claim 35, wherein the provided olefin stream further contains propane, and the first fraction further comprises at least a majority of propane present in the olefin stream.

45. The method of claim 35, wherein the provided olefin stream further contains propane, and the second fraction further comprises at least a majority of the propane present in the olefin stream.