Process for producing olefins

• US 7,361,799 B2
• Filed: 03/25/2005
• Issued: 04/22/2008
• Est. Priority Date: 07/14/2004
• Status: Active Grant

• Current Assignee: ExxonMobil Chemical Patents Inc. (Exxon Mobil Corporation)
• Original Assignee: ExxonMobil Chemical Patents Inc. (Exxon Mobil Corporation)
• Inventors: Ruziska, Philip Andrew, Brinen, Jeffrey L., Kuechler, Keith H.
• Primary Examiner(s): Caldarola; Glenn
• Assistant Examiner(s): BULLOCK, IN SUK C
• Application Number:
  US11/090,422
• Publication Number:
  US 20060014991A1
• Time in Patent Office: 1,124 Days
• Field of Search: 585638-640, 585/802, 585/809, 585/833
• US Class Current: 585/809
• CPC Class Codes: C07C 1/20 starting from organic compounds containing only oxygen atoms as heteroatoms
• CPC Class Codes: C07C 11/02 Alkenes
• CPC Class Codes: C07C 11/04 Ethylene
• CPC Class Codes: C07C 11/06 Propene
• CPC Class Codes: C07C 7/10 by extraction, i.e. purification or separation of liquid hydrocarbons with the aid of liquids
• CPC Class Codes: Y02P 30/20 using bio-feedstock
• CPC Class Codes: Y02P 30/40 Ethylene production

Abstract

A process is described for producing olefins from a vapor product stream from an oxygenate to olefin conversion reaction, the vapor product stream comprising C₂ to C₄ olefins, C₅+ hydrocarbons, at least one oxygenate and water. In the process, the vapor product stream is cooled to remove water therefrom and produce a first vapor effluent stream. The first vapor effluent stream is then cooled and compressed to produce a condensed liquid effluent stream comprising C₅+ hydrocarbons and at least one oxygenate, and a residual vapor effluent stream comprising C₂ to C₄ olefins. At least part of the condensed liquid effluent stream is contacted with a liquid water-containing stream in a liquid-liquid contacting device to at least partly separate said condensed liquid effluent stream, or portion thereof, into an aqueous phase rich in said at least one oxygenate and an organic phase rich in said C₅+ hydrocarbons.

Claims

1. A process for producing olefins comprising:

(a) providing a vapor product stream from an oxygenate to olefin reaction comprising C₂ to C₄ olefins, C₅+ hydrocarbons, at least one oxygenate and water;

(b) cooling the vapor product stream to remove water therefrom and produce a first vapor effluent stream;

(c) compressing and cooling the first vapor effluent stream to produce a second effluent stream that is at least partially in the vapor state;

(d) washing at least part of the second effluent stream with a liquid alcohol-containing stream to remove at least a portion of at least one oxygenate from the second effluent stream in a wash liquid effluent stream, and produce a wash vapor effluent stream comprising C₂ to C₄ olefins, the wash liquid effluent stream further comprising C₅+ hydrocarbons and alcohol contained in the liquid alcohol-containing stream;

(e) contacting at least a portion of the wash liquid effluent stream with a liquid water-containing stream in a liquid-liquid contacting device to at least partially separate said wash liquid effluent stream, or portion thereof, into an aqueous phase rich in said at least one oxygenate and alcohol from the liquid alcohol-containing stream, and an organic phase rich in said C₅+ hydrocarbons;

(f) washing the wash vapor effluent stream with a stream containing predominantly water to form a water-washed vapor effluent stream and a water-washed liquid effluent stream;

(g) treating the water-washed vapor effluent stream with a basic component to remove carbon dioxide therefrom, thus forming a CO₂-depleted, water-washed vapor effluent stream; and

(h) cooling the CO₂-depleted, water-washed vapor effluent stream to a temperature below 90°

F. (32°

C.) and separating the cooled, CO₂-depleted, water-washed vapor effluent stream into a partially dried vapor stream containing light olefins and a wet liquid stream.

2. The process of claim 1 wherein said liquid alcohol-containing stream comprises at least one alcohol from the group consisting of methanol and ethanol.

3. The process of claim 1 wherein the wash liquid effluent stream produced in (d) comprises up to about 20 wt. % aromatics.

4. The process of claim 1 wherein the wash liquid effluent stream produced in (d) comprises at least about 1 wt. % of said at least one oxygenate.

5. The process of claim 1 wherein the wash liquid effluent stream produced in (d) comprises at least about 10 wt. % alcohol contained in the liquid alcohol-containing stream.

6. The process of claim 1 wherein the liquid water-containing stream in (e) comprises at least 90 wt. % water.

7. The process of claim 1 wherein said organic phase in (e) comprises up to about 95 wt. % C₅+ hydrocarbons.

8. The process of claim 1 wherein said organic phase in (e) comprises up to about 40 wt. % C₂ to C₆ carbonyls.

9. The process of claim 1 wherein said contacting (e) is conducted at a pressure of from about 170 kPaa (10 psig) to about 2514 kPaa (350 psig), and a temperature of from about 1°

C. (34°

F.) to about 54°

C. (130°

F.).

10. The process of claim 1 further comprising exposing said wash liquid effluent stream produced in (d) to one or more reductions in pressure to form a wash flash liquid effluent stream, wherein said wash flash liquid effluent stream is provided as the portion of the wash liquid effluent stream for contacting (e).

11. The process of claim 10 wherein the wash flash liquid effluent stream comprises up to about 20 wt. % aromatics and at least about 30 wt. % alcohol contained in the liquid alcohol-containing stream.

12. The process of claim 1 wherein (c) comprises compressing the first vapor effluent stream;

cooling the compressed first vapor effluent stream to produce a first condensed liquid effluent stream and a first residual vapor effluent stream;

compressing the first residual vapor effluent stream; and

cooling the compressed first residual vapor effluent stream to produce a second residual vapor effluent stream that is at least partially in the vapor state, said second residual vapor effluent stream being provided for said washing (d).

13. A process for producing olefins comprising:

(a) providing a vapor product stream from an oxygenate to olefin reaction comprising C₂ to C₄ olefins, C₅+ hydrocarbons, at least one oxygenate and water;

(b) cooling the vapor product stream to remove water therefrom and produce a first vapor effluent stream;

(c) compressing and cooling the first vapor effluent stream to produce a condensed liquid effluent stream comprising C5+ hydrocarbons and at least one oxygenate, and a residual vapor effluent stream comprising C₂ to C₄ olefins, and;

(d) washing at least part of the residual vapor effluent stream with a liquid alcohol-containing stream to produce a wash vapor effluent stream comprising C₂ to C₄ olefins, and a wash liquid effluent stream comprising said at least one oxygenated hydrocarbon and said C₅+ hydrocarbons;

(e) contacting at least a portion of the condensed liquid effluent stream produced in (c) and at least a portion of the wash liquid effluent stream produced in (d) with a liquid water-containing stream in a liquid-liquid contacting device to at least partially separate said condensed liquid effluent stream produced in (c) and the wash liquid effluent stream produced in (d), or portions thereof, into an aqueous phase rich in said at least one oxygenate and alcohol contained in the liquid alcohol containing stream, and an organic phase rich in said C₅+ hydrocarbons;

(f) washing the wash vapor effluent stream with a stream containing predominantly water to form a water-washed vapor effluent stream and a water-washed liquid effluent stream;

(g) treating the water-washed vapor effluent stream with a basic component to remove carbon dioxide therefrom, thus forming a CO₂-depleted, water-washed vapor effluent stream; and

(h) cooling the CO₂-depleted, water-washed vapor effluent stream to a temperature below 90°

F. (32°

C.) and separating the cooled, CO₂-depleted, water-washed vapor effluent stream into a partially dried vapor stream containing light olefins and a wet liquid stream.

14. The process of claim 13 wherein said liquid alcohol-containing stream comprises methanol and/or ethanol.

15. The process of claim 13 wherein the wash liquid effluent stream produced in (d) comprises up to about 20 wt. % aromatics.

16. The process of claim 13 wherein the wash liquid effluent stream produced in (d) comprises at least about 1 wt. % of said at least one oxygenate.

17. The process of claim 13 wherein the wash liquid effluent stream produced in (d) comprises at least about 10 wt. % alcohol contained in the liquid alcohol-containing stream.

18. The process of claim 13 further comprising exposing said wash liquid effluent stream produced in (d) to one or more reductions in pressure to form a wash flash liquid effluent stream, wherein said wash flash liquid effluent stream is provided as the portion of the wash liquid effluent stream for contacting (e).

19. The process of claim 18 wherein the wash flash liquid effluent stream comprises up to about 20 wt. % aromatics and at least about 20 wt. % alcohol contained in the liquid alcohol-containing stream.

20. The process of claim 13 wherein said organic phase in (e) comprises up to about 95 wt. % C₅+ hydrocarbons and up to about 40 wt. % C₂ to C₆ carbonyls.

21. The process of claim 13 wherein said contacting (e) is conducted at a pressure of from about 170 kPaa (10 psig) to about 2514 kPaa (350 psig), and a temperature of from about 1°

C. (34°

F.) to about 54°

C. (130°

F.).

22. The process of claim 13 wherein said condensed liquid effluent stream and said wash liquid effluent stream, or portions thereof, are combined, and said combined stream, or portion thereof, is provided for contacting (e).

23. The process of claim 13 wherein said condensed liquid effluent stream and said wash liquid effluent stream, or portions thereof, are combined, and said combined stream, or portion thereof, is exposed to one or more reductions in pressure to form a flash liquid effluent stream, wherein said flash liquid effluent stream is provided as the portion of the wash liquid effluent stream for contacting (e).

24. The process of claim 13 wherein (c) comprises compressing the first vapor effluent stream;

cooling the compressed first vapor effluent stream to produce a first condensed liquid effluent stream and a first residual vapor effluent stream;

compressing the first residual vapor effluent stream; and

cooling the compressed first residual vapor effluent stream to produce a second effluent stream that is at least partially in the vapor state, at least part of said second effluent stream being provided for said washing (d).

25. The process of claim 24 wherein said second effluent stream is segregated into a second condensed liquid effluent stream and a second residual vapor effluent stream, said second residual vapor effluent stream being provided for said washing (d).

26. The process of claim 25 wherein said first condensed liquid effluent stream, said second condensed liquid effluent stream or said wash liquid effluent stream, or portions thereof, is exposed to one or more reductions in pressure to form a flash liquid effluent stream, wherein said flash liquid effluent stream is provided as the portion of the condensed liquid effluent stream and wash liquid effluent stream for contacting (e).

27. The process of claim 25 wherein said second condensed liquid effluent stream and said wash liquid effluent stream, or portions thereof, are exposed to a reduction in pressure along with the compressed and cooled first vapor effluent stream to produce a first residual vapor effluent stream and a common first condensed liquid effluent stream and first flash liquid effluent stream, said common first condensed liquid effluent stream and first flash liquid effluent stream being exposed to a further reduction in pressure to produce a second flash liquid effluent stream, and said second flash liquid effluent stream being provided as the portion of the condensed liquid effluent stream and wash liquid effluent stream for contacting (e).