Multicomponent adsorption process

• US 4,812,147 A
• Filed: 11/08/1985
• Issued: 03/14/1989
• Est. Priority Date: 11/08/1985
• Status: Expired due to Fees

• Current Assignee: Praxair Technology Incorporated (Linde Plc)
• Original Assignee: Union Carbide Corporation (Dow, Inc.)
• Inventors: BeVier, William E.
• Primary Examiner(s): Spitzer, Robert
• Application Number:
  US06/796,240
• Time in Patent Office: 1,222 Days
• Field of Search: 55/25, 55/26, 55/31, 55/33-35, 55/58, 55/60, 55/62, 55/68, 55/74, 55/75, 55/77
• US Class Current: 95/95
• CPC Class Codes: B01D 2257/504 Carbon dioxide
• CPC Class Codes: B01D 2257/702 Hydrocarbons
• CPC Class Codes: B01D 2257/80 Water
• CPC Class Codes: B01D 2259/404 using four beds
• CPC Class Codes: B01D 53/04 with stationary adsorbents B01D53/025 takes precedence
• CPC Class Codes: B01D 53/047 Pressure swing adsorption
• CPC Class Codes: B01D 53/08 according to the "moving bed" method
• CPC Class Codes: Y02C 20/40 of CO2

Abstract

A process to absorb more than one component from a gaseous stream comprising passing the gaseous stream sequentially in contact with separate and distinct adsorbent masses wherein not all of the more strongly sorbed component is removed in a single adsorbent mass. The process exhibits improved overall efficiency over conventional multicomponent adsorption processes.

Claims

1. A process for the removal by adsorption of more than one component from a gaseous stream comprising:

(a) passing a gaseous stream containing two components, a first component and a second component, wherein the first component is more strongly sorbed than the second component, in contact with a first mass of adsorbent to transfer the majority but not all of the first component to the first mass of adsorbent;

(b) passing the resulting gaseous stream in contact with a second mass of adsorbent, separate and spaced from the first mass of adsorbent, to transfer substantially all of the remaining first component and substantially all of the second component to the second mass of adsorbent;

(c) regenerating the second mass of adsorbent to a low residual loading with respect to the first component; and

(d) regenerating the first mass of adsorbent to a high residual loading.

2. The process of claim 1 wherein at least 90 percent of the first component is transferred to the first mass of adsorbent.

3. The process of claim 1 wherein at most about 99.5 percent of the first component is transferred to the first mass of adsorbent.

4. The process of claim 1 wherein at least one of the first and second mass of adsorbent contacts the gaseous stream in a fixed bed.

5. The process of claim 1 wherein at least one of the first and second mass of adsorbent contacts the gaseous stream in a moving bed.

6. The process of claim 5 wherein the contact in the moving bed is cocurrent.

7. The process of claim 5 wherein the contact in the moving bed is countercurrent.

8. The process of claim 1 wherein the first and second mass of adsorbent are the same type of adsorbent.

9. The process of claim 1 wherein the first and second mass of adsorbent are different types of adsorbent.

10. The process of claim 1 wherein at least one mass of adsorbent is molecular sieve.

11. The process of claim 1 wherein the gaseous stream is air, the first component is water vapor and the second component is carbon dioxide.

12. The process of claim 1 wherein the gaseous stream is natural gas, the first component is water vapor, and the second component is carbon dioxide.

13. The process of claim 1 wherein the gaseous stream is hydrogen, the first component is ethylene, and the second component is methane.

14. The process of claim 1 wherein the gaseous stream is helium, the first component is carbon dioxide and the second component is methane.

15. The process of claim 1 wherein at least one of the regenerations is carried out by changing the pressure on the adsorbent mass.

16. The process of claim 1 wherein at least one of the regenerations is carried out by changing the temperature of the adsorbent mass.

17. The process of claim 1 wherein at least one of the regenerations is carried out by contacting purge gas in countercurrent flow with the adsorbent mass.

18. The process of claim 17 wherein the purge gas is nitrogen.

19. The process of claim 17 wherein both regenerations are carried out by contacting purge gas in countercurrent flow with adsorbent mass.

20. The process of claim 19 wherein at least a part of the purge gas after regeneration of the second adsorbent mass is employed to make up at least part of the purge gas requirement for the regeneration of the first adsorbent mass.

21. The process of claim 19 wherein at least part of the purge gas after regeneration of the second adsorbent mass is employed to make up all of the purge gas requirement for the regeneration of the first adsorbent mass.

22. The process of claim 19 wherein the purge gas is heated prior to contact with the second adsorbent mass.

23. A process for the removal by adsorption of more than one component from a gaseous stream comprising:

(a) providing a gaseous stream containing at least two components, said components ranked by order of sorption as first through N^th component with the first component being the most strongly sorbed and the N^th component being the least strongly sorbed;

(b) passing the gaseous stream in contact with a first mass of absorbent to transfer the majority but not all of the first component to the first mass of adsorbent;

(c) passing the resulting gaseous stream in contact with a series of N-2 separate and spaced adsorbent masses, each adsorbent mass being associated with one component ranked 2 through N-1, wherein in each serial adsorbent mass the majority but not all of its associated component is removed from the stream to the said serial adsorbent mass along with the remainder of the component, more strongly sorbed than the associated component, which is still in the gaseous stream, while essentially none of the component(s) less strongly sorbed than the associated component are removed from the gaseous stream;

(d) passing the gaseous stream resulting from step (c) in contact with the N^th adsorbent mass wherein substantially all of the remainder of the N-1^th component and substantially all of the N^th component are transferred to the N^th adsorbent mass;

and

(e) regenerating the first mass of adsorbent to a higher residual loading with respect to the first component then the residual loading of any of the other adsorbent masses.

24. The process of claim 23 wherein the gaseous stream contains three components to be removed by adsorption.

25. The process of claim 24 wherein the gaseous stream is air, the first component is water vapor, the second component is carbon dioxide and the third component is a hydrocarbon gas.

26. The process of claim 24 wherein the gaseous stream is argon, the first component is water vapor, the second component is carbon dioxide and the third component is nitrogen.