Apparatus and system for combined temperature and pressure swing adsorption processes related thereto

Patent metadata

Field	Value
Publication number	US-10293298-B2
Application number	US-201615233631-A
Country	US
Kind code	B2
Filing date	Aug 10, 2016
Priority date	Sep 2, 2015
Publication date	May 21, 2019
Grant date	May 21, 2019

Abstract

Provided are apparatus and systems for performing a swing adsorption process. This swing adsorption process may involve passing streams through adsorbent bed units to treat the pipeline quality natural gas to form a stream that complies with liquefied natural gas (LNG) specifications. The process may involve a combined TSA and PSA process, which is utilized to remove contaminants from the feed stream.

First claim

What is claimed is:

1. A process for removing contaminants from a gaseous feed stream, the process comprising:
a) performing one or more adsorption steps, wherein each of the one or more adsorption steps comprise passing a gaseous feed stream through an adsorbent bed unit having an adsorbent bed to separate one or more contaminants from the gaseous feed stream to form a product stream;
b) performing one or more depressurization steps, wherein the pressure within the adsorbent bed unit is reduced by a predetermined amount with each successive depressurization step;
c) performing a heating step, wherein the heating step comprises passing a heating stream at a heating temperature into the adsorbent bed unit, wherein the heating stream is passed in a countercurrent direction relative to the direction of the feed stream and the heating temperature is less than 500° F. (260° C.);
d) performing purge step, wherein the purge step comprises passing a purge stream into the adsorbent bed unit, wherein the purge stream is passed in a countercurrent direction relative to the direction of the feed stream and wherein a temperature differential exists at the end of the purge step in a range between 50° F. (27.8° C.) and 400° F. (222.2° C.), wherein the temperature differential is the difference in temperatures between a feed end of the adsorbent bed and a product end of the adsorbent bed; and
e) repeating the steps a) to d) for at least one additional cycle, wherein the cycle duration is for a period greater than 1 second and less than 600 seconds.

2. The process of claim 1 , wherein the temperature differential is in a range between 125° F. (69.4° C.) and 350° F. (194.4° C.).

3. The process of claim 1 , wherein the temperature differential is in a range between 175° F. (97.2° C.) and 300° F. (166.7° C.).

4. The process of claim 1 , wherein the gaseous feed stream is a hydrocarbon containing stream having greater than one volume percent hydrocarbons based on the total volume of the feed stream.

5. The process of claim 1 , wherein the gaseous feed stream comprises hydrocarbons and CO 2 , wherein the CO 2 content is in the range of one hundred parts per million volume and less than or equal to about 5 volume % of the gaseous feed stream.

6. The process of claim 1 , wherein the adsorbent bed unit is configured to lower the carbon dioxide (CO 2 ) level to less than 50 parts per million.

7. The process of claim 1 , wherein the gaseous feed stream is provided at a feed pressure in the range between 50 bar absolute (bara) and 150 bara and at a feed temperature in the range between −40° F. (−40° C.) and 200° F. (93.3° C.).

8. The process of claim 1 , wherein passing the heating stream comprises heating a portion of the adsorbent bed from a product end of the adsorbent bed to 40% of the bed length to the within 10% of the heating temperature.

9. The process of claim 1 , wherein passing the heating stream comprises heating a portion of the adsorbent bed from a. product end of the adsorbent bed to 10% of the bed length to a temperature of the difference between the heating temperature and the temperature differential.

10. The process of claim 1 , further comprising:
passing an input stream to a dehydration adsorption unit; and
adsorbing a portion of the H 2 O from the input stream during an adsorption step, wherein the remaining portion of the input stream is the gaseous feed stream; and
conducting away a portion of the H 2 O from the dehydration adsorption unit during a regeneration step.

11. The process of claim 1 , further comprising:
passing the product stream from the adsorbent bed unit to a liquefied natural gas process unit; and
separating a flash fuel stream of high purity methane from the LNG process unit to be utilized as at least a portion of the purge stream.

12. The process of claim 1 , wherein the cycle duration is greater than 2 seconds and less than 300 seconds.

13. The process of claim 1 , wherein passing the heating stream at the heating temperature into the adsorbent bed unit further comprising recycling the heating stream through the adsorbent bed via a heating loop.

14. The process of claim 13 , further comprising passing the heating stream to a heating unit to increase the temperature of the heating stream prior to passing the heating stream at the heating temperature into the adsorbent bed unit.

15. The process of claim 14 , further comprising passing the heating stream from a blower to the heating unit to increase the pressure of the heating stream prior to passing the heating stream to the adsorbent bed unit.

16. The process of claim 1 , comprising performing a second purge step prior to the purge step, wherein the second purge step comprises passing a second purge stream into the adsorbent bed unit to remove contaminants from the adsorbent bed unit, wherein the second purge stream is an output purge product stream from another adsorbent bed unit.

17. The process of claim 1 , wherein passing the heating stream at the heating temperature into the adsorbent bed unit further comprising passing an output purge stream from another adsorbent bed unit.

18. A system for removing contaminants from a gaseous feed stream, the system comprising:
an adsorbent bed unit configured to separate contaminants from a gaseous feed stream and to output a product stream, wherein the adsorbent bed unit comprises an adsorbent bed;
a liquefied natural gas process unit in fluid communication with the adsorbent bed unit and configured to receive the product stream and separate the product stream into a final product stream and a flash fuel stream of high methane; and
one or more purge units in fluid communication with the liquefied natural gas process unit and configured to provide a purge stream to the adsorbent bed unit, wherein the purge stream is provided from one of a portion of the product stream, the flash fuel stream of high purity methane, and any combination thereof;
a heating mechanism in fluid communication with the adsorbent bed unit and configured to:
pass a heating stream at a heating temperature into the adsorbent bed unit, wherein the heating stream is configured to create a temperature differential in a range between 50° F. (27.8° C.) and 400° F. (222.2° C.), wherein the temperature differential is the difference in temperatures between a feed end of the adsorbent bed and a product end of the adsorbent bed; and
combine a portion of the heating stream with the purge stream that is passed through the adsorbent bed unit.

19. The system of claim 18 , further comprising a dehydration adsorption unit in fluid communication with the adsorbent bed unit and configured to receive an input stream and form the gaseous feed stream, wherein the dehydration adsorption unit is configured to adsorb a portion of the H 2 O from the input stream during an adsorption step, wherein the remaining portion of the input stream is the gaseous feed stream; and to conduct away a portion of the H 2 O from the dehydration adsorption unit during a regeneration step.

20. The system of claim 19 , wherein the dehydration adsorption unit is a molecular sieve adsorption unit.

21. The system of claim 19 , wherein the dehydration adsorption unit is an adsorbent bed unit configured to perform a rapid cycle thermal swing adsorption process.

22. The system of claim 18 , wherein the heating mechanism is a heating loop that includes a heating unit configured to heat the heating stream prior to passing the heating stream

Assignees

• Marshall Bennett D
• Kelley Bruce T
• Nagavarapu Ananda K
• Deckman Harry W
• Johnson Robert A
• Ramkumar Shwetha
• Oelfke Russell H
• Exxonmobil Upstream Res Co

Inventors

• Marshall Bennett D
• Kelley Bruce T
• Nagavarapu Ananda K
• Deckman Harry W
• Johnson Robert A
• Ramkumar Shwetha
• Oelfke Russell H

Classifications

• B01D53/0473

  Rapid pressure swing adsorption · CPC title

• Y02C10/08

  Cross-Sectional Technologies · mapped topic

• B01D53/0407

  Constructional details of adsorbing systems · CPC title

• B01D2259/4009

  using hot gas · CPC title

• B01D53/047

  Pressure swing adsorption · CPC title