Processes for cooling a wet natural gas stream

Patent metadata

Field	Value
Publication number	US-9662609-B2
Application number	US-201514686434-A
Country	US
Kind code	B2
Filing date	Apr 14, 2015
Priority date	Apr 14, 2015
Publication date	May 30, 2017
Grant date	May 30, 2017

Abstract

One or more processes to cool a wet natural gas feed stream before the feed stream is passed to a guard bed zone for a membrane separation unit. The processes utilizing an existing processes stream that has a temperature below the hydrate formation temperature of the feed stream. The existing stream may be a residue stream from the membrane separation unit which is heat exchanged with a cleaned stream from the guard bed zone. The cooled clean stream may then be used to cool the wet feed stream.

First claim

What is claimed is:

1. A process for removing compounds from a natural gas stream to provide a feed stream for a membrane separation unit, the process comprising:
removing heat from a wet feed stream to provide a cooled wet feed stream;
separating water and heavy hydrocarbons from the cooled wet feed stream to provide a cleaned feed stream; and,
removing heat from the cleaned feed stream to provide a cooled cleaned feed stream, wherein heat is removed from the cleaned feed stream by a cooling stream having a temperature below a hydrate formation temperature for the wet feed stream, and wherein the cooled cleaned feed stream is used to remove heat from the wet feed stream; and
separating carbon dioxide from the cooled cleaned feed stream in a membrane separation unit to provide a carbon dioxide lean stream; wherein the carbon dioxide lean stream comprise the cooling stream.

2. The process of claim 1 wherein the cooling stream has a temperature between −15 to 15° C. (5 to 59° F.).

3. The process of claim 1 further comprising:
removing heat from the cooled cleaned feed stream after the cooled cleaned feed stream has removed heat from the wet feed stream.

4. The process of claim 1 further comprising:
combining a portion of the cleaned feed stream with the cooled cleaned feed stream, after the cooled cleaned feed stream has removed heat from the wet feed stream.

5. The process of claim 1 wherein water and heavy hydrocarbons are separated from the cooled wet feed stream in a phase separation vessel as a liquid stream.

6. The process of claim 5 wherein water and heavy hydrocarbons are further separated from the cooled wet feed stream in a separation zone.

7. The process of claim 6 wherein the separation zone includes a thermal swing adsorption unit having at least one an adsorption vessel including an adsorbent.

8. A process for removing compounds from a natural gas stream to provide a feed stream for a membrane separation unit, the process comprising:
passing a wet feed stream to a first heat exchange zone to remove heat from the wet feed stream and to provide a cooled wet feed stream;
separating water and heavy hydrocarbons from the cooled wet feed stream in a guard bed zone to provide a cleaned feed stream;
passing the cleaned feed stream to a second heat exchange zone to remove heat from the cleaned feed stream with a cooling stream and to provide a cooled cleaned feed stream; and,
passing the cooled cleaned feed stream to the first heat exchange zone to remove heat from the wet feed stream,
wherein the cooling stream has a temperature below a hydrate formation temperature for the wet feed stream.

9. The process of claim 8 further comprising:
passing the cooled cleaned feed stream from the first heat exchange zone to a third heat exchange zone to remove heat from the cooled cleaned feed stream.

10. The process of claim 9 further comprising:
passing the cooling stream from the second heat exchange zone to the third heat exchange zone.

11. The process of claim 10 further comprising:
passing the cooled cleaned feed stream from the third heat exchange zone to a membrane separation zone.

12. The process of claim 11 , wherein the cooling stream is passed from the membrane separation zone to the second exchange zone.

13. The process of claim 9 wherein the first heat exchange zone comprises a heat exchanger and the third heat exchange zone comprises a heat exchanger.

14. The process of claim 13 wherein the heat exchanger in the first heat exchange zone and the heat exchanger in the third heat exchange zone are formed into a single unit.

15. The process of claim 13 wherein the heat exchanger in the first heat exchange zone and the heat exchanger in the third heat exchange zone are separated.

16. The process of claim 8 wherein the cooling stream is comprises a gaseous stream from a membrane separation zone.

17. The process of claim 8 wherein the guard bed zone comprises a thermal swing adsorption unit.

18. The process of claim 17 wherein the thermal swing adsorption unit includes a phase separation vessel.

Assignees

• Uop Llc

Inventors

• Cnop Tom
• Ng Seow Ching

Classifications

• C10L3/101

  Removal of contaminants · CPC title

• B01D53/261

  by adsorption · CPC title

• C10L2290/06

  Heat exchange, direct or indirect · CPC title

• B01D2257/80

  Water · CPC title

• C10L3/106

  of water · CPC title