Method and apparatus for thermal swing adsorption and thermally-enhanced pressure swing adsorption

• US 6,746,515 B2
• Filed: 04/29/2002
• Issued: 06/08/2004
• Est. Priority Date: 04/30/2001
• Status: Expired due to Term

• Current Assignee: Battelle Memorial Institute
• Original Assignee: Battelle Memorial Institute
• Inventors: TeGrotenhuis, Ward E., Rassat, Scot D., Drost, Kevin, Vishwanathan, Vilayanur V., Wegeng, Robert S.
• Primary Examiner(s): LAWRENCE JR, FRANK M
• Application Number:
  US10/135,891
• Publication Number:
  US 20020194990A1
• Time in Patent Office: 771 Days
• Field of Search: 95/95, 95/96, 951/06, 951/14, 951/15, 951/16, 951/39, 429/13, 429/19-21, 429/26
• US Class Current: 95/96
• CPC Class Codes: B01D 2253/108 Zeolites
• CPC Class Codes: B01D 2257/504 Carbon dioxide
• CPC Class Codes: B01D 2257/80 Water
• CPC Class Codes: B01D 2259/40088 by heating
• CPC Class Codes: B01D 2259/4575 in aeroplanes or space ships
• CPC Class Codes: B01D 53/02 by adsorption, e.g. preparative gas chromatography solid sorbent compositions B01J20/00, preparation of inorganic compounds or elements C01
• CPC Class Codes: B01D 53/0446 Means for feeding or distributing gases
• CPC Class Codes: B01D 53/0462 Temperature swing adsorption
• CPC Class Codes: B01D 53/047 Pressure swing adsorption
• CPC Class Codes: B01D 53/06 with moving adsorbents, e.g. rotating beds B01D53/025 takes precedence
• CPC Class Codes: C01B 2203/043 Regenerative adsorption process in two or more beds, one for adsorption, the other for regeneration
• CPC Class Codes: C01B 2203/0475 the impurity being carbon dioxide
• CPC Class Codes: C01B 2203/066 with fuel cells
• CPC Class Codes: C01B 3/56 by contacting with solids; Regeneration of used solids C01B3/508 takes precedence
• CPC Class Codes: H01M 8/0263 having meandering or serpentine paths
• CPC Class Codes: H01M 8/0267 having heating or cooling means, e.g. heaters or coolant flow channels
• CPC Class Codes: H01M 8/04014 Heat exchange using gaseous fluids; Heat exchange by combustion of reactants
• CPC Class Codes: H01M 8/04225 during start-up
• CPC Class Codes: H01M 8/04302 applied during start-up
• CPC Class Codes: H01M 8/0612 from carbon-containing material
• CPC Class Codes: H01M 8/0662 : Treatment of gaseous reactants or gaseous residues, e.g. cleaning
• CPC Class Codes: H01M 8/2483 : characterised by internal manifolds
• CPC Class Codes: Y02C 20/40 : of CO2
• CPC Class Codes: Y02E 60/50 : Fuel cells
• CPC Class Codes: Y02P 20/10 : Process efficiency
• CPC Class Codes: Y02P 20/133 : Renewable energy sources, e.g. sunlight
• CPC Class Codes: Y02P 20/151 : Reduction of greenhouse gas [GHG] emissions, e.g. CO2
• CPC Class Codes: Y02P 20/50 : Improvements relating to the production of bulk chemicals

Abstract

The present invention provides compact adsorption systems that are capable of rapid temperature swings and rapid cycling. Novel methods of thermal swing adsorption and thermally-enhanced pressure swing adsorption are also described. In some aspects of the invention, a gas is passed through the adsorbent thus allowing heat exchangers to be very close to all portions of the adsorbent and utilize less space. In another aspect, the adsorption media is selectively heated, thus reducing energy costs. Methods and systems for gas adsorption/desorption having improved energy efficiency with capability of short cycle times are also described. In another aspect, the apparatus or methods utilize heat exchange channels of varying lengths that have volumes controlled to provide equal heat fluxes. Methods of fuel cell startup are also described. Advantages of the invention include the ability to use (typically) 30-100 times less adsorbent compared to conventional systems.

Claims

1. A method of adsorbing and desorbing a gas in a sorption pump, wherein the sorption pump comprises:

an adsorption layer comprising an adsorption mesochannel containing adsorption media; and

a heat exchanger layer adjacent the adsorption layer, the heat exchanger layer comprising a first region comprising a first heat exchange fluid pathway and a second region comprising a second heat exchange fluid pathway;

the first fluid pathway having mutually perpendicular dimensions of length, width and height, and a second fluid pathway;

wherein the first fluid pathway connects a header and a footer;

wherein the second fluid pathway has mutually perpendicular dimensions of length, width and height, and wherein the second fluid pathway connects a header and a footer;

wherein length is measured in the direction of net fluid flow through the heat exchanger layer;

wherein the first fluid pathway has a shorter average length than the second fluid pathway; and

wherein the product of the average width and average height (width×

height) of the second fluid pathway is larger than the product of the average width and average height (width×

height) of the first fluid pathway;

the method comprising;

adsorbing a gas onto an adsorbent in the adsorbent mesochannel to form an adsorbed gas at a first temperature;

passing a heat exchange fluid into the first and the second fluid pathways, wherein the heat exchange fluid is at a temperature that is higher than the first temperature; and

desorbing at least a portion of the adsorbed gas.

2. The method of claim 1 wherein the desorbing step is conducted simultaneously with a step of reducing the partial pressure of a gas species that is adsorbed in the adsorbent.

18. The method of claim 1 wherein the sorption pump comprises at least 3 cells disposed about central axis in single unit, wherein each cell comprises:

an adsorption layer comprising an adsorption mesochannel containing adsorption media; and

a heat exchanger layer adjacent the adsorption layer, the heat exchanger layer comprising a first region comprising a first heat exchange fluid pathway and a second region comprising a second heat exchange fluid pathway;

wherein the first fluid pathway has mutually perpendicular dimensions of length, width and height, and wherein the first fluid pathway connects a header and a footer;

wherein the second fluid pathway has mutually perpendicular dimensions of length, width and height, and wherein the second fluid pathway connects a header and a footer;

wherein length is measured in the direction of net fluid flow through the heat exchanger layer;

wherein the first fluid pathway has a shorter average length than the second fluid pathway; and

wherein the product of the average width and average height (width×

height) of the second fluid pathway is larger than the product of the average width and average height (width×

height) of the first fluid pathway.

19. The method of claim 1 wherein the sorption pump is comprised of a material that has a lower density and lower heat capacity than stainless steel.

20. The method of claim 1 used to modify the partial pressure of H₂S, CO₂, H₂O, CO, H₂, or hydrocarbon gases.

3. A method of starting a fuel cell, comprising:

(a) producing hydrogen from a reformer and adsorbing less than 10% of the hydrogen produced by the reformer in hydrogen sorbent that is disposed in a mesochannel within a sorption pump;

(b) in the sorption pump, heating the hydrogen sorbent that is disposed in a mesochannel, causing hydrogen to be desorbed; and

passing at least a portion of the desorbed hydrogen into a non-operating fuel cell; and

(c) using the desorbed hydrogen to start the fuel cell.

4. The method of claim 3 comprising repeating steps (a)-(c) at least 10 times.

5. The method of claim 3 wherein the hydrogen sorbent comprises a metal hydride.

6. The method of claim 3 wherein heat is supplied to the mesochannel from an adjacent heat exchange channel.

7. The method of claim 6 wherein the fuel cell is in an automobile.

8. The method of claim 6 wherein the sorption pump comprises an adsorption layer comprising an adsorption mesochannel containing adsorption media;

and

a heat exchanger layer adjacent the adsorption layer, the heat exchanger layer comprising a first region comprising a first heat exchange, fluid pathway and a second region comprising a second heat exchange fluid pathway;

the first fluid pathway having mutually perpendicular dimensions of length, width and height, and a second fluid pathway;

wherein the first fluid pathway connects a header and a footer;

wherein the second fluid pathway has mutually perpendicular dimensions of length, width and height, and wherein the second fluid pathway connects a header and a footer;

wherein length is measured in the direction of net fluid flow through the heat exchanger layer;

wherein the first fluid pathway has a shorter average length than the second fluid pathway; and

wherein the product of the average width and average height (width×

height) of the second fluid pathway is larger than the product of the average width and average height (width×

height) of the first fluid pathway.

9. The method of claim 6 wherein heating is supplied by a compact combustor.

10. The method of claim 6 wherein the sorption pump is housed in a separate unit from the fuel cell.

11. The method of claim 6 further comprising a sorption pump that purifies reformer output.

16. The method of claim 11 wherein the sorption pump is a thermochemical compressor.

17. The method of claim 3 wherein step (b) is conducted simultaneously with a step of reducing the partial pressure of a gas species that is adsorbed in the adsorbent.

21. The method of claim 3 wherein the sorption pump is comprised of a material that has a lower density and lower heat capacity than stainless steel.

22. The method of claim 3 wherein the sorption pump contains at least two adsorption mesochannels in a laminated device.

23. The method of claim 11 wherein the sorption pump that purifies reformer output removes water, CO₂ or hydrocarbons from the reformer output before the output enters said mesochannel within a sorption pump.

24. The method of claim 3 wherein the sorption pump and the fuel cell are integrated within the same single unit.

25. The method of claim 3 further comprising an additional sorption pump that compresses hydrogen to increase pressure going into said mesochannel within a sorption pump.

27. The method of claim 25 wherein less than 10% of the hydrogen produced by the reformer is adsorbed by the sorption pump.

12. A method of gas adsorption and desorption, comprising:

in a gas adsorption and desorption apparatus comprising at least one adsorption mesochannel and at least one heat exchanger;

adsorbing gas into adsorption media in at least one adsorption mesochannel and, simultaneously, removing heat from the adsorption media into a heat-absorbing heat exchanger;

subsequently, adding heat from a heat-supplying heat exchanger to the adsorption media in the at least one adsorption mesochannel and desorbing gas from the adsorption media;

wherein the combined steps of adsorbing a gas and desorbing a gas form a complete cycle; and

wherein, in a complete cycle, at least 0.1 mol of gas per minute per liter of apparatus is adsorbed and desorbed.

13. The method of claim 12 wherein a single heat exchanger performs the functions of both absorbing and supplying heat.

14. The method of claim 12 wherein cycle time is less than 2 mm and at least 90% of the adsorbent capacity of the adsorbent is utilized in each cycle.

15. The method of claim 14 wherein the gas comprises CO₂.

32. The method of claim 12 wherein the heat-supplying heat exchanger comprises an electrical resistance heater.

33. The method of claim 12 wherein the heat-absorbing heat exchanger comprises a thermoelectric cooler.

34. The method of claim 12 wherein the temperature of the adsorption media during the complete cycle differs by less than 200°

C.

35. The method of claim 12 wherein the temperature of the adsorption media during the complete cycle differs by less than 100°

C.

36. The method of claim 12 wherein the temperature of the adsorption media during the complete cycle differs by 50 to 200°

C.

37. The method of claim 36 wherein from 0.1 to 1 mole of gas per minute per liter of apparatus is adsorbed and desorbed in a complete cycle.

38. The method of claim 34 wherein the cycle time is less than 5 minutes.

39. The method of claim 34 wherein the adsorption and desorption apparatus comprises a laminated device comprising at least 2 repeat units.

40. The method of claim 12 wherein the adsorption and desorption apparatus comprises a laminated device comprising at least 12 repeat units.

41. The method of claim 12 wherein the adsorption and desorption apparatus comprises at least 3 cells disposed around a central axis wherein the cells increase-in size as they extend away from the central axis.

42. The method of claim 12 wherein the adsorption and desorption apparatus comprises multiple heat exchanger fluid channels wherein several separate heat exchange fluids are delivered to and collected from multiple heat exchanger fluid channels.

43. The method of claim 12 wherein said complete cycle comprises one stage of a multi-stage process.

44. The method of claim 43 comprising at least two stages operating in series.

45. The method of claim 42 wherein the gas comprises CO₂;

and further wherein CO₂ is compressed in the first stage and the compressed CO₂ is fed to a cooled adsorption cell in a second stage.

46. The method of claim 14 wherein the gas comprises H₂S, CO, H₂O, CO₂, or H₂.

47. The method of claim 14 wherein the temperature of the adsorption media during the complete cycle differs by less than 200°

C.

26. A method of starting a fuel cell, comprising:

(a) producing hydrogen from a reformer and adsorbing a portion of the hydrogen produced by the reformer in a hydrogen sorbent that is disposed in a mesochannel within a sorption pump;

wherein the reformer produces an output of hydrogen and impurity gases and further comprising a second sorption pump that purifies the reformer output before this output reaches the mesochannel;

(b) in the sorption pump, heating the hydrogen sorbent that is disposed in a mesochannel, causing hydrogen to be desorbed; and

passing at least a portion of the desorbed hydrogen into a non-operating fuel cell; and

(c) using the desorbed hydrogen to start the fuel cell.

28. The method of claim 26 wherein the sorption pump contains at least two adsorption mesochannels in a laminated device.

29. The method of claim 26 wherein heating is supplied by a compact combustor.

30. The method of claim 26 comprising repeating steps (a)-(c) at least 10 times.

31. The method of claim 26 wherein heat is supplied to the mesochannel from an adjacent heat exchange channel.