Methods of Removing Contaminants from a Hydrocarbon Stream by Swing Adsorption and Related Apparatus and Systems

• US 20130327216A1
• Filed: 02/27/2012
• Published: 12/12/2013
• Est. Priority Date: 03/01/2011
• Status: Active Grant

• Current Assignee: Exxonmobil Upstream Research Company (Exxon Mobil Corporation)
• Original Assignee: Exxonmobil Upstream Research Company (Exxon Mobil Corporation)
• Inventors: Deckman, Harry W., Johnson, Robert A., Tammera, Robert F., Anderson, Thomas N.
• Granted Patent: US 9,168,485 B2
• Time in Patent Office: Days
• US Class Current: 95/96
• CPC Class Codes: B01D 2253/308 Pore size
• CPC Class Codes: B01D 2257/304 Hydrogen sulfide
• CPC Class Codes: B01D 2257/504 Carbon dioxide
• CPC Class Codes: B01D 2259/40018 with more than three sub-steps
• CPC Class Codes: B01D 2259/40033 with more than three sub-steps
• CPC Class Codes: B01D 2259/40035 Equalization
• CPC Class Codes: B01D 2259/40041 with more than three sub-steps
• CPC Class Codes: B01D 2259/40043 Purging
• CPC Class Codes: B01D 2259/40075 More than ten
• CPC Class Codes: B01D 2259/4068 using more than ten beds
• CPC Class Codes: B01D 53/047 Pressure swing adsorption
• CPC Class Codes: B01D 53/0473 Rapid pressure swing adsorption
• CPC Class Codes: B01D 53/053 with storage or buffer vessel
• CPC Class Codes: Y02C 20/40 of CO2

Abstract

A swing adsorption process for removing contaminants from a gaseous feed stream through a combination of a selective adsorbent material containing an effective amount of a non-adsorbent filler, adsorbent contactor design, and adsorption cycle design.

Claims

1. A cyclical swing adsorption process for removing contaminants from gas feed streams comprising the steps of:

a) passing a gaseous feed stream at a feed pressure through a adsorbent bed unit having an adsorbent bed to separate one or more contaminants from the gaseous feed stream to form a product stream;

b) interrupting the flow of the gaseous feed stream;

c) performing a plurality of depressurization steps, wherein each depressurization step comprises passing a portion of the gas from the adsorbent bed unit into one or more equalization vessels that are dedicated to the adsorbent bed unit and the depressurization step to reduce the pressure within the adsorbent bed unit;

d) performing a plurality of re-pressurization steps, wherein each re-pressurization step comprises passing the portion of the gas from one or more equalization vessels associated with one of the plurality of depressurization steps to the adsorbent bed unit to increase the pressure within the adsorbent bed unit ; and

e) repeating the steps a) to d) for at least one additional cycle.

2. The cyclical swing adsorption process of claim 1, further comprising a step of purging the adsorbent bed unit after the plurality of depressurization steps and before the plurality of equalization steps.

3. The cyclical swing adsorption process of claim 1, further comprising one or more blow-down steps to reduce the pressure in the adsorbent bed unit after the plurality of depressurization steps and before the plurality of equalization steps.

4. The cyclical swing adsorption process of claim 1, wherein the ratio of the pressure within the adsorbent bed unit at one depressurization step divided by the pressure within the adsorbent bed unit at a subsequent depressurization step is less than about 0.98.

5. The cyclical swing adsorption process of claim 1, wherein the ratio of the pressure within the adsorbent bed unit at one re-pressurization step divided by the pressure within the adsorbent bed unit at a previous re-pressurization step is less than about 0.98.

6. The cyclical swing adsorption process of claim 1, wherein the gaseous feed stream is a hydrocarbon containing stream having >

20 volume percent hydrocarbons based on the total volume of the gaseous feed stream.

7. The cyclical swing adsorption process of claim 6, wherein the hydrocarbon containing stream has >

2 volume percent CO₂ based on the total volume of the gaseous feed stream and an adsorbent material in the adsorbent bed has a higher selectivity to CO₂ as compared to hydrocarbons.

8. The cyclical swing adsorption process of claim 5, wherein the product stream has greater than 98 volume percent hydrocarbons based on the total volume of the product stream.

9. The cyclical swing adsorption process of claim 1, wherein the gaseous feed stream is a hydrocarbon containing stream having >

20 volume percent CO₂ based on the total volume of the gaseous containing stream.

10. The cyclical swing adsorption process of claim 9, wherein the hydrocarbon containing stream has >

2 volume percent N₂ based on the total volume of the gaseous containing stream and the adsorbent material has a higher selectivity to N₂ as compared to hydrocarbons.

11. The cyclical swing adsorption process of claim 1, wherein the one or more contaminants being adsorbed comprise CO₂ or H₂S.

12. The cyclical swing adsorption process of claim 1, wherein the cycle of steps a) through d) is performed in a time interval less than about 60 seconds.

13. The cyclical swing adsorption process of claim 1, wherein the cycle of steps a) through d) is performed in a time interval less than about 20 seconds.

14. The cyclical swing adsorption process of claim 1, further comprising passing the gaseous feed stream to a manifold that distributes the gaseous feed steam to one of a plurality of the adsorbent bed unit, wherein each of the adsorbent bed units operate cycles independently of each other.

15. The cyclical swing adsorption process of claim 1, wherein the steps a) to d) are steps in the cycle of one or more of a pressure swing adsorption process, thermal swing adsorption process, calcination, partial pressure swing or displacement purge adsorption process and combinations of these processes.

16. The cyclical swing adsorption process of claim 1, wherein the gaseous feed stream comprises one or more contaminants of H₂S in a range from about 0.001 volume percent to about 70 volume percent based on the total volume of the gaseous feed stream.

17. The cyclical swing adsorption process of claim 1, wherein an adsorbent material in adsorbent bed has less than about 20% of its open pore volume in pores with diameters greater than about 20 angstroms and less than about 1 micron.

18. The cyclical swing adsorption process of claim 1, further comprising recapturing pressure from at least one of the equalization vessels after the equalization vessel has be utilized in the one of the plurality of equalization steps.

19. A adsorbent bed assembly comprising:

a housing having an interior region and configured to maintain a pressure from 0 bar to 80 bar within the interior region;

an adsorbent bed disposed in the interior region and having a plurality of flow channels through the adsorbent bed, wherein the plurality of flow channels have an adsorbent material disposed on at least one surface within the plurality of flow channels;

an inlet conduit disposed adjacent to the adsorbent bed and configured to pass a stream into the interior region from a location external to the housing;

an outlet conduit disposed adjacent to the adsorbent bed and configured to pass a stream into the interior region from a location external to the housing; and

a plurality of equalization vessels in fluid communication with the interior region and dedicated to the adsorbent bed.

20. The adsorbent bed assembly of claim 19, wherein at least one of the plurality of equalization vessels is configured to support the housing and adsorbent bed.

21. The adsorbent bed assembly of claim 19, wherein each of the plurality of equalization vessels has a pressure reset valve and is configured to exchange fluids with a conduit in a first position and to prevent fluid flow to the conduit in a second position.

22. The adsorbent bed assembly of claim 19, wherein each of the plurality of equalization vessels is configured to exchange fluids with the housing during one of a plurality of re-pressurization steps and one of a plurality of depressurization steps in each cycle and configured to prevent fluid flow in other re-pressurization steps and other depressurization steps in each cycle.

23. The adsorbent bed assembly of claim 19, wherein the adsorbent material in the adsorbent bed has less than about 20% of its open pore volume in pores with diameters greater than about 20 angstroms and less than about 1 micron.

24. A swing adsorption system comprising:

a plurality of adsorbent bed assemblies, wherein each adsorbent bed assembly comprises;

a housing having an interior region and configured to maintain a pressure from 0 bar a to 80 bar a within the interior region;

an adsorbent bed disposed in the interior region and having a plurality of flow channels through the adsorbent bed, wherein the plurality of flow channels have an adsorbent material disposed on at least one surface within the plurality of flow channels;

a inlet conduit disposed adjacent to the adsorbent bed and configured to pass a stream into the interior region from a location external to the housing;

an outlet conduit disposed adjacent to the adsorbent bed and configured to pass a stream into the interior region from a location external to the housing; and

a plurality of equalization vessels in fluid communication with the interior region and dedicated to the adsorbent bed.

25. The swing adsorption system of claim 24, wherein at least one of the plurality of equalization vessels for at least one of each adsorbent bed assembly is configured to support the housing and adsorbent bed.

26. The swing adsorption system of claim 24, wherein each of the plurality of equalization vessels has a pressure reset valve and is configured to exchange fluids with a conduit in a first position and to prevent fluid flow to the conduit in a second position.

27. The swing adsorption system of claim 24, wherein at least one of the plurality of adsorbent bed assemblies has each of the plurality of equalization vessels configured to exchange fluids with the housing during one of a plurality of re-pressurization steps and one of a plurality of depressurization steps in each cycle and configured to prevent fluid flow in other re-pressurization steps and other depressurization steps in each cycle.

28. The swing adsorption system of claim 24, wherein the adsorbent material in the adsorbent bed has less than about 20% of its open pore volume in pores with diameters greater than about 20 angstroms and less than about 1 micron.

29. The swing adsorption system of claim 24, wherein each of the plurality of adsorbent bed assemblies is configured to independently utilize the plurality of equalization vessels associated with that adsorbent bed assembly.