Steam reformer with internal hydrogen purification

• US 5,997,594 A
• Filed: 10/15/1997
• Issued: 12/07/1999
• Est. Priority Date: 10/30/1996
• Status: Expired due to Term

• Current Assignee: DCNS SA (Government of France)
• Original Assignee: Northwest Power Systems LLC (IdaTech Ltd.)
• Inventors: Edlund, David J., Pledger, William A.
• Primary Examiner(s): BHAT, NINA NMN
• Application Number:
  US08/951,091
• Time in Patent Office: 783 Days
• Field of Search: 48/76, 48/127.7, 48/63, 422/217, 422/218, 423/652, 423/655, 95/56, 96/7, 96/11
• US Class Current: 48/76
• CPC Class Codes: B01D 2257/108 Hydrogen
• CPC Class Codes: B01D 2323/12 Specific ratios of components used
• CPC Class Codes: B01D 53/228 characterised by specific membranes
• CPC Class Codes: B01D 53/229 Integrated processes (Diffusion and at least one other process, e.g. adsorption, absorption)
• CPC Class Codes: B01D 69/10 Supported membranes; Membrane supports
• CPC Class Codes: B01D 69/1071 Woven, non-woven or net mesh
• CPC Class Codes: B01D 71/022 Metals
• CPC Class Codes: B01D 71/0221 Group 4 or 5 metals
• CPC Class Codes: B01D 71/02231 Palladium
• CPC Class Codes: B01D 71/02232 Nickel
• CPC Class Codes: B01J 19/2475 Membrane reactors
• CPC Class Codes: B01J 2208/00053 of the heat exchange medium
• CPC Class Codes: B01J 2208/00061 of the reactants
• CPC Class Codes: B01J 2208/00106 by indirect heat exchange
• CPC Class Codes: B01J 2208/00141 Coils
• CPC Class Codes: B01J 2208/00309 with two or more reactions in heat exchange with each other, such as an endothermic reaction in heat exchange with an exothermic reaction
• CPC Class Codes: B01J 2208/00415 electric resistance heaters
• CPC Class Codes: B01J 2208/00495 using insulating materials or refractories
• CPC Class Codes: B01J 2208/0053 Controlling multiple zones along the direction of flow, e.g. pre-heating and after-cooling
• CPC Class Codes: B01J 2208/00539 Pressure
• CPC Class Codes: B01J 2208/00548 : Flow
• CPC Class Codes: B01J 8/009 : Membranes, e.g. feeding or removing reactants or products to or from the catalyst bed through a membrane
• CPC Class Codes: B01J 8/04 : the fluid passing successively through two or more beds
• CPC Class Codes: B01J 8/0465 : the beds being concentric
• CPC Class Codes: B01J 8/0469 : the beds being superimposed one above the other
• CPC Class Codes: B01J 8/0496 : Heating or cooling the reactor
• CPC Class Codes: B01J 8/062 : being installed in a furnace
• CPC Class Codes: B01J 8/067 : Heating or cooling the reactor B01J8/062 takes precedence
• CPC Class Codes: C01B 2203/0233 : the reforming step being a steam reforming step
• CPC Class Codes: C01B 2203/0283 : containing a CO-shift step, i.e. a water gas shift step
• CPC Class Codes: C01B 2203/041 : In-situ membrane purification during hydrogen production
• CPC Class Codes: C01B 2203/0445 : Selective methanation
• CPC Class Codes: C01B 2203/047 : the impurity being carbon monoxide
• CPC Class Codes: C01B 2203/0475 : the impurity being carbon dioxide
• CPC Class Codes: C01B 2203/066 : with fuel cells
• CPC Class Codes: C01B 2203/0811 : by combustion of fuel
• CPC Class Codes: C01B 2203/0822 : the fuel containing hydrogen
• CPC Class Codes: C01B 2203/0827 : at least part of the fuel being a recycle stream
• CPC Class Codes: C01B 2203/085 : by electric heating
• CPC Class Codes: C01B 2203/0866 : by combination of different heating methods
• CPC Class Codes: C01B 2203/1011 : Packed bed of catalytic structures, e.g. particles, packing elements
• CPC Class Codes: C01B 2203/1041 : Composition of the catalyst
• CPC Class Codes: C01B 2203/1058 : Nickel catalysts
• CPC Class Codes: C01B 2203/1076 : Copper or zinc-based catalysts
• CPC Class Codes: C01B 2203/1217 : Alcohols
• CPC Class Codes: C01B 2203/1223 : Methanol
• CPC Class Codes: C01B 2203/1241 : Natural gas or methane
• CPC Class Codes: C01B 2203/1247 : Higher hydrocarbons
• CPC Class Codes: C01B 2203/1288 : Evaporation of one or more of the different feed components
• CPC Class Codes: C01B 2203/142 : At least two reforming, decomposition or partial oxidation steps in series
• CPC Class Codes: C01B 2203/146 : At least two purification steps in series
• CPC Class Codes: C01B 2203/1604 : Starting up the process
• CPC Class Codes: C01B 2203/1628 : Controlling the pressure
• CPC Class Codes: C01B 2203/1633 : Measuring the pressure
• CPC Class Codes: C01B 2203/82 : Several process steps of C01B2203/02 - C01B2203/08 integrated into a single apparatus
• CPC Class Codes: C01B 3/323 : Catalytic reaction of gaseous or liquid organic compounds other than hydrocarbons with gasifying agents
• CPC Class Codes: C01B 3/326 : characterised by the catalyst
• CPC Class Codes: C01B 3/382 : Multi-step processes
• CPC Class Codes: C01B 3/501 : by diffusion
• CPC Class Codes: C01B 3/503 : characterised by the membrane
• CPC Class Codes: C01B 3/505 : Membranes containing palladium
• CPC Class Codes: C01B 3/586 : the reaction being a methanation reaction
• CPC Class Codes: C12F 5/00 : Preparation of denatured alcohol
• CPC Class Codes: G01N 1/34 : Purifying; Cleaning processes or apparatus for extracting or separating nucleic acids from biological samples C12N15/1003
• CPC Class Codes: Y02E 60/32 : Hydrogen storage
• CPC Class Codes: Y02P 20/10 : Process efficiency
• CPC Class Codes: Y02P 20/52 : using catalysts, e.g. selective catalysts

Abstract

A steam reformer with internal hydrogen purification includes internal bulk hydrogen purification, internal hydrogen polishing to remove trace levels of carbon monoxide and carbon dioxide, an integrated combustion method utilizing waste gas to heat the reformer, efficient integration of heat transfer, and a compact design. One steam reformer shown includes a concentric cylindrical architecture nesting an annular combustion region, an annular reforming region, an annular hydrogen transport region, and a cylindrical polishing region. Other reformers shown include modified combustion systems distributed within a reformation region, isolated vaporization chambers, combustion systems providing uniform temperature gradient, and plate membrane construction methods.

Claims

1. A steam reformer, comprising:

a reformation chamber containing a reformation catalyst, wherein the reformation chamber is adapted to receive a reformation feedstock and produce a reformate stream including hydrogen therefrom; and

a membrane module adapted to receive the reformate stream and divide the reformate stream into a byproduct stream and a hydrogen product stream, the membrane module comprising;

a plurality of hydrogen permeable membranes, each having a reformate side and a permeate side, wherein the membranes are spaced-apart from each other and oriented with their permeate sides generally facing each other to define a harvesting conduit extending therebetween, and further wherein the hydrogen product stream is formed from the portion of the reformate stream that passes through the membranes to the harvesting conduit, with the remaining portion of the reformate stream which remains on the reformate side of the membranes forming the byproduct stream;

a support within the harvesting conduit adapted to support the membranes, wherein the support includes a pair of generally opposed surfaces which are adapted to provide support to a respective one of the permeate sides of the membranes; and

a product outlet port in fluid communication with the harvesting conduit and through which the hydrogen product stream is withdrawn from the membrane module.

2. The reformer of claim 1, wherein the support engages but is not bonded to the membranes.

3. The reformer of claim 1, wherein the support is formed from a porous material.

4. The reformer of claim 1, wherein the support is adapted to permit flow of gas both parallel and transverse to the permeate sides of the membranes.

5. The reformer of claim 1, wherein the support defines a gas stream path through the harvesting conduit, with the stream path extending parallel and transverse to the permeate sides of the membranes.

6. The reformer of claim 1, wherein the support includes mesh.

7. The reformer of claim 6, wherein the support includes an inner mesh screen with outer mesh screens separating the inner mesh screen and the permeate sides of the membranes.

8. The reformer of claim 7, wherein the inner mesh screen is coarser than the outer mesh screens.

9. The reformer of claim 1, wherein the membranes define generally parallel, spaced-apart planes with the harvesting conduit extending therebetween and being at least substantially coextensive therewith.

10. The reformer of claim 1, wherein each membrane includes an edge region secured to a frame that extends beyond the edge region of the membrane.

11. The reformer of claim 10, wherein the frame is bonded to the edge region by ultrasonic welding.

12. The reformer of claim 10, wherein the reformer includes a plurality of gas transport conduits extending through the frames to selectively deliver the reformate stream to the reformate sides of the membranes, remove the product stream from the harvesting conduit, and to remove the byproduct stream.

13. The reformer of claim 12, wherein at least one of the conduits is adapted to deliver the byproduct stream to a combustion region of the reformer.

14. The reformer of claim 12, wherein at least one of the conduits is adapted to deliver the product stream to a polishing catalyst bed.

15. The reformer of claim 1, wherein the support and the membranes whose permeate sides are supported by the support comprise a membrane envelope, and further wherein the membrane module includes plural membrane envelopes.

16. The reformer of claim 15, wherein each membrane envelope includes an inlet port through which at least a portion of the reformate stream is delivered to the membrane envelope, a product outlet port through which the product stream is withdrawn from the harvesting conduit, and a byproduct port through which the byproduct stream is withdrawn from the membrane envelope, and further wherein the corresponding ports of the plurality of membrane envelopes are in fluid communication with each other to respectively form an inlet conduit, a product conduit and a byproduct conduit.

17. The reformer of claim 16, wherein the byproduct conduit is adapted to deliver the byproduct stream to a combustion region of the reformer.

18. The reformer of claim 16, wherein the product conduit is adapted to deliver the product stream to a polishing catalyst bed.

19. The reformer of claim 1, wherein each hydrogen permeable membrane is formed from at least one of palladium or a palladium alloy.

20. The reformer of claim 19, wherein each membrane contains less than 200 ppm carbon.

21. The reformer of claim 20, wherein each membrane contains less than 100 ppm carbon.

22. The reformer of claim 21, wherein each membrane contains less than 50 ppm carbon.

23. A hydrogen-selective membrane envelope, comprising:

a hydrogen permeable membrane region having an inlet side and a permeate side;

another hydrogen permeable membrane region having an inlet side and a permeate side, wherein the membrane regions are spaced-apart from each other with their permeate sides facing each other and defining a harvesting conduit extending therebetween;

a support within the harvesting conduit and adapted to support the permeate sides of the membrane regions, wherein the support enables gas passing through the membrane regions to the harvesting conduit to travel transverse and parallel to the permeate sides of the membrane regions; and

an outlet port through which gas may be harvested from the harvesting conduit.

24. The membrane envelope of claim 23, wherein the envelope is in fluid communication with a steam reformer and adapted to receive a reformate stream containing hydrogen therefrom.

25. The membrane envelope of claim 24, wherein the envelope is coupled to the steam reformer.

26. The membrane envelope of claim 25, wherein the envelope is at least partially contained within the steam reformer.

27. The membrane envelope of claim 23, wherein the support engages the permeate sides of the membrane regions but is not bonded to the permeate sides of the membrane regions.

28. The membrane envelope of claim 23, wherein the support includes mesh.

29. The membrane envelope of claim 28, wherein the support includes an inner mesh screen and outer mesh screens separating the inner mesh screen and the permeate sides of the membrane regions.

30. The membrane envelope of claim 29, wherein the inner mesh screen is coarser than the outer mesh screens.

31. The membrane envelope of claim 23, wherein the membrane regions define generally parallel, spaced-apart surfaces with the harvesting conduit extending therebetween.

32. The membrane envelope of claim 23, wherein each membrane region includes an outer edge region to which a frame is bonded.

33. The membrane envelope of claim 32, wherein each frame is bonded to the outer edge region of a corresponding one of the membrane regions by ultrasonic welding.

34. The membrane envelope of claim 23, wherein each of the membranes is formed from at least one of palladium and a palladium alloy.

35. The membrane envelope of claim 24, wherein each of the membranes contains less than 200 ppm carbon.

36. The membrane envelope of claim 35, wherein each of the membranes contains less than 100 ppm carbon.

37. The membrane envelope of claim 36, wherein each of the membranes contains less than 50 ppm carbon.