METHODS AND APPARATUSES FOR PURIFYING CRUDE PROPANE

• US 20190330128A1
• Filed: 04/24/2019
• Published: 10/31/2019
• Est. Priority Date: 04/25/2018
• Status: Active Grant

• Current Assignee: Lyondell Chemical Technology LP (Lyondellbasell Industries NV)
• Original Assignee: Lyondell Chemical Technology LP (Lyondellbasell Industries NV)
• Inventors: Keyvani, Majid
• Granted Patent: US 10,640,437 B2
• Time in Patent Office: Days
• CPC Class Codes: B01D 53/1487 Removing organic compounds
• CPC Class Codes: B01J 20/18 Synthetic zeolitic molecular sieves
• CPC Class Codes: B01J 29/7007 Zeolite Beta
• CPC Class Codes: C07C 27/26 Purification; Separation; Stabilisation
• CPC Class Codes: C07C 47/06 Acetaldehyde
• CPC Class Codes: C07C 7/005 Processes comprising at least two steps in series
• CPC Class Codes: C07C 7/13 by molecular-sieve technique
• CPC Class Codes: C07C 7/148 by treatment giving rise to a chemical modification of at least one compound
• CPC Class Codes: C07C 7/20 Use of additives, e.g. for stabilisation
• CPC Class Codes: C07C 9/08 Propane
• CPC Class Codes: C07D 301/32 Separation; Purification
• CPC Class Codes: C07D 303/04 containing only hydrogen and carbon atoms in addition to the ring oxygen atoms

Abstract

Systems and methods for purifying crude propane streams are provided herein. For example, in some embodiments, methods are provided including passing a crude propane stream to a fixed bed reactor containing a Beta zeolite configured to reduce the propylene oxide content of the crude propane stream and produce a propylene-treated stream and contacting the propylene-treated stream with an acetaldehyde scavenger to produce a treated propane stream. In some embodiments, methods are provided including passing a crude propane stream through a water wash system to provide a treated propane stream having a lower propylene oxide content, a lower acetaldehyde content, or both.

Claims

1. A method of purifying a crude propane stream, the method comprising:

providing a crude propane stream comprising propane, propylene oxide, acetaldehyde, and propylene;

contacting the crude propane stream with a zeolite catalyst and an acetaldehyde scavenger under conditions sufficient to reduce the propylene oxide content and the acetaldehyde content of the crude propane stream and produce a first treated propane stream.

2. The method of claim 1, wherein the method comprises first contacting the crude propane stream with the zeolite catalyst and subsequently contacting with an acetaldehyde scavenger to produce the first treated propane stream.

3. The method of claim 1, wherein the crude propane stream has a temperature of from about 60°

F. to about 200°

F. and a pressure of from about 250 psig to about 350 psig.

4. The method of claim 1 wherein the zeolite catalyst comprises a Beta zeolite catalyst.

5. The method of claim 1, wherein the acetaldehyde scavenger is an amino alcohol.

6. The method of claim 1, wherein the acetaldehyde scavenger is Dorf Ketal™

DA 2604 or Dow AMP-95®

.

7. The method of claim 1, wherein the acetaldehyde scavenger is a carbohydrazide base anti-polymerant.

8. The method of claim 1, wherein the crude propane stream comprises from about 2 wt % to about 6 wt % propylene oxide.

9. The method of claim 8, wherein the first treated propane stream comprises less than 100 ppm of propylene oxide.

10. The method of claim 1, wherein the crude propane stream comprises from about 2 wt % to about 4 wt % acetaldehyde.

11. The method of claim 10, wherein the first treated propane stream comprises less than about 1 wt % acetaldehyde.

12. The method of claim 1, comprising contacting the crude propane stream with the Beta zeolite catalyst in a fixed bed reactor and contacting an output of the fixed bed reactor with the acetaldehyde scavenger in a static mixer downstream of the fixed bed reactor.

13. A reactor for purifying a crude propane stream, the reactor comprising:

a fixed bed reactor having a crude propane stream inlet, the crude propane stream comprising propane, propylene oxide, acetaldehyde, and propylene;

the fixed bed reactor comprising a Beta zeolite configured to contact the crude propane stream, reduce the propylene oxide content of the crude propane stream, and produce a first treated propane stream; and

an acetaldehyde scavenger system configured to contact one or more of the crude propane stream and the first treated propane stream with one or more acetaldehyde scavengers under conditions sufficient to reduce the acetaldehyde content of the one or more of the crude propane stream and the first treated propane stream.

14. The reactor system of claim 13, wherein the acetaldehyde scavenger system comprises a static mixer configured to mix at least a portion of the one or more of the crude propane stream and the first treated propane stream with an acetaldehyde scavenger to produce a second treated propane stream.

15. A propane production system comprising:

a first system configured to produce a first hydrocarbon stream comprising C3 hydrocarbons;

a distillation column configured to separate propylene and propane and produce a crude propane stream;

the reactor of claim 13 configured to purify the crude propane stream.

16. A method of purifying a crude propane stream comprising:

providing a crude propane stream comprising propane, propylene oxide, acetaldehyde, and propylene; and

passing the crude propane stream through a water wash system to provide a treated propane stream having a lower propylene oxide content, a lower acetaldehyde content, or both;

wherein the water wash system comprises treating water in a water wash column with at least 15 theoretical stages.

17. The method of claim 16, wherein the crude propane stream comprises from about 2 wt % to about 6 wt % propylene oxide and wherein the first treated propane stream comprises less than about 100 ppm propylene oxide.

18. The method of claim 16, wherein the crude propane stream comprises from about 2 wt % to about 4 wt % acetaldehyde and wherein the first treated propane stream comprises less than about 1000 ppm acetaldehyde.

19. The method of claim 16, wherein the weight ratio of the treating water to the crude propane stream is from about 2 to about 4.

20. The method of claim 16, wherein the treating water has a pH of from about 6.8 to 7.6.