Fibrous composite catalytic structures and their use in chemical reactors

• US 20120077664A1
• Filed: 08/17/2007
• Published: 03/29/2012
• Est. Priority Date: 08/17/2007
• Status: Active Grant

• Current Assignee: Juzer Jangbarwala
• Original Assignee: Juzer Jangbarwala
• Inventors: Jangbarwala, Juzer
• Granted Patent: US 8,314,044 B2
• Time in Patent Office: Days
• US Class Current: 502/1
• CPC Class Codes: B01J 21/18 Carbon
• CPC Class Codes: B01J 23/80 with zinc, cadmium or mercury
• CPC Class Codes: B01J 35/58 Fabrics or filaments
• CPC Class Codes: B01J 37/343 of ultrasonic wave energy
• CPC Class Codes: C01B 2203/0233 the reforming step being a steam reforming step
• CPC Class Codes: C01B 2203/1017 characterised by the form of the structure
• CPC Class Codes: C01B 2203/1076 Copper or zinc-based catalysts
• CPC Class Codes: C01B 2203/1223 Methanol
• CPC Class Codes: C01B 3/326 characterised by the catalyst
• CPC Class Codes: H01M 8/0631 Reactor construction specially adapted for combination reactor/fuel cell hydrogen C01B3/00; reactors for physicochemical processes B01J19/00
• CPC Class Codes: Y02E 60/50 Fuel cells
• CPC Class Codes: Y02P 20/52 using catalysts, e.g. selective catalysts
• CPC Class Codes: Y10T 428/23921 With particles
• CPC Class Codes: Y10T 428/23986 With coating, impregnation, or bond
• CPC Class Codes: Y10T 428/249928 Fiber embedded in a ceramic, glass, or carbon matrix
• CPC Class Codes: Y10T 428/249929 Fibers are aligned substantially parallel
• CPC Class Codes: Y10T 428/249953 Composite having voids in a component [e.g., porous, cellular, etc.]
• CPC Class Codes: Y10T 428/25 Web or sheet containing structurally defined element or component and including a second component containing structurally defined particles
• CPC Class Codes: Y10T 428/2913 Rod, strand, filament or fiber
• CPC Class Codes: Y10T 428/2918 including free carbon or carbide or therewith [not as steel]
• CPC Class Codes: Y10T 428/2927 : including structurally defined particulate matter
• CPC Class Codes: Y10T 428/294 : including metal or compound thereof [excluding glass, ceramic and asbestos]
• CPC Class Codes: Y10T 442/107 : Comprising at least two chemically different fibers
• CPC Class Codes: Y10T 442/133 : Inorganic fiber-containing scrim
• CPC Class Codes: Y10T 442/134 : Including a carbon or carbonized fiber
• CPC Class Codes: Y10T 442/152 : Including a free metal or alloy constituent
• CPC Class Codes: Y10T 442/159 : Including a nonwoven fabric which is not a scrim
• CPC Class Codes: Y10T 442/164 : Including a preformed film, foil, or sheet
• CPC Class Codes: Y10T 442/184 : Nonwoven scrim
• CPC Class Codes: Y10T 442/186 : Comprising a composite fiber

Abstract

Permeable composite fibrous catalytic sheets comprised of at least three distinct solid phases. A first solid phase is an electrically conductive phase comprised of randomly oriented electrically conductive carbon fibers. A second solid phase is a 3-dimensional porous network of a non-conductive porous ceramic material. A third phase is comprised of catalytic particles dispersed on said 3-dimensional porous network.

Claims

1. A catalytic sheet comprised of three solid phases wherein a first solid phase is comprised of a plurality of randomly oriented electrically conductive carbon fibers, a second solid phase is comprised of a 3-dimensional network of a substantially non-conductive porous ceramic material intermingled with said first solid phase, and a third solid phase comprised of a plurality of catalyst particles dispersed on said 3-dimensional network of porous ceramic material.

2. The catalytic sheet of claim 1 wherein the carbon fibers are graphitic fibers.

3. The catalytic sheet of claim 1 wherein the ceramic material is selected from the group consisting of alumina, silica, silica-alumina, titania, zirconia, and magnesia.

4. The catalytic sheet of claim 3 wherein the ceramic material is alumina.

5. The catalytic sheet of claim 1 wherein the catalyst is a methanol reforming catalyst.

6. The catalytic sheet of claim 5 wherein the methanol reforming catalyst contains copper.

7. The catalyst sheet of claim 5 wherein the methanol reforming catalyst contains both copper and zinc oxide.

8. The catalytic sheet of claim 1 which also contains an effective amount of non-conductive ceramic fibers.

9. The catalytic sheet of claim 8 wherein the ceramic fibers are selected from the group consisting of zirconia fibers, alumina fibers, aluminosilica fibers and aluminoborosilicate fibers.

10. The catalytic sheet of claim 1 wherein there is also present in an effective amount of graphite nanofibers.

11. The catalytic sheet of claim 10 wherein the graphitic nanofibers are comprised of graphite platelets that are aligned parallel, perpendicular or at an angle to the longitudinal axis of the nanofiber.

12. A catalytic sheet comprised of three solid phases wherein a first solid phase is comprised of a plurality of randomly oriented electrically conductive carbon fibers;

a second solid phase which is comprised of a 3-dimensional network of an substantially non-conductive porous ceramic material intermingled with said first solid phase, which ceramic material is selected from the group consisting of alumina, silica, alumina-silica, titania, zirconia, and magnesia; and

a third solid phase which is comprised of a plurality of particles of methanol reforming catalyst dispersed on said 3-dimensional network of substantially non-conductive porous ceramic material.

13. The catalytic sheet of claim 12 wherein the ceramic material is alumina.

14. The catalytic sheet of claim 12 wherein the methanol reforming catalyst contains copper as a catalytic metal.

15. The catalytic sheet of claim 14 wherein the methanol reforming catalyst contains both copper and zinc.

16. The catalytic sheet of claim 12 which also contains an effective amount of non-conductive ceramic fibers.

17. The catalytic sheet of claim 16 wherein the ceramic fibers are selected from the group consisting of alumina fibers, aluminosilica fibers and aluminaborosilicate fibers.

18. The catalytic sheet of claim 12 wherein there is also present in an effective amount of graphite nanofibers.

19. The catalytic sheet of claim 18 wherein the graphitic nanofibers are comprised of graphite platelets that are aligned parallel, perpendicular or at an angle to the longitudinal axis of the nanofiber.

20. A process for producing catalytic sheets comprised of three solid phases wherein a first solid phase is comprised of a plurality of randomly oriented electrically conductive carbon fibers, a second solid phase is comprised of a 3-dimensional network of a substantially non-conductive porous ceramic material intermingled with said first solid phase, and a third solid phase comprised of a plurality of catalyst particles dispersed on said 3-dimensional network of porous ceramic material;

which process comprises;

a) providing a porous mat of randomly oriented electrically conductive carbon fibers;

b) preparing a blend of an effective amount of catalyst particles in a dispersing liquid;

c) passing said blend through said porous mat of electrically conductive carbon fibers an effective number of times until a predetermined amount of catalyst particles are deposited onto the carbon fibers of said porous mat;

d) driving-off substantially all liquid dispersing agent that may be present on said catalyst-containing carbon fiber mat;

e) preparing a ceramic sol;

f) introducing said ceramic sol into an open mold at least as large as said carbon fiber mat;

g) submerging said catalyst-containing carbon fiber mat into said ceramic sol for an effective amount of time to allow substantially all of said catalyst particles to migrate from said carbon fibers to said alumina sol;

h) driving-off substantially all liquid from step g) above thereby resulting in a 3-dimensional porous network of ceramic material intermingled throughout said carbon fiber mat, which 3-dimensional porous network of non-conductive ceramic material now supports substantially all of said catalyst particles;

i) calcining dried intermingled 3-dimensional porous network of ceramic material and carbon fiber mat of step h) above in an oxygen-containing atmosphere and at a temperature from about 100°

C. to about 500°

C.; and

j) subjecting said calcined 3-dimensional porous network of ceramic material and carbon fiber mat of step i) above in a hydrogen-containing atmosphere at a temperature from about 200°

C. to about 500°

C. for an effective amount of time to activate substantially all of said catalyst particles, thereby resulting in a catalytic sheet product.

21. The process of claim 20 wherein the liquid dispersing agent is selected from the group consisting of water and C₁ to C₃ aliphatic alcohols.

22. The process of claim 21 wherein the carbon fibers are graphitic.

23. The process of claim 20 wherein the catalyst is a methanol reforming catalyst.

24. The process of claim 23 wherein the methanol reforming catalyst contains copper.

25. The process of claim 23 wherein the methanol reforming catalyst contains both copper and zinc.

26. The process of claim 20 wherein the ceramic material is selected from the group consisting of alumina, silica, silica-alumina, titania, and magnesia.

27. The process of claim 26 wherein the ceramic material is alumina.

28. The process of claim 20 which also contains an effective amount of non-conductive ceramic fibers.

29. The process of claim 28 wherein the ceramic fibers are selected from the group consisting of alumina fibers, aluminosilica fibers and aluminoborosilicate fibers.

30. The process of claim 20 wherein there is also present in an effective amount of graphite nanofibers.

31. The process of claim 30 wherein the graphitic nanofibers are comprised of graphite platelets that are aligned parallel, perpendicular or at an angle to the longitudinal axis of the nanofiber.

32. The process of claim 22 wherein:

i) the catalyst is a methanol reforming catalyst containing both copper and zinc as catalytic metals;

ii) the ceramic material is selected from the group consisting of alumina, silica, silica-alumina, titania, and magnesia; and

iii) an effective amount of non-conductive ceramic fibers are present and are selected from the group consisting of alumina fibers, aluminosilica fibers and aluminoborosilicate fibers.

33. A process for producing catalytic sheets comprised of three solid phases wherein a first solid phase is comprised of a plurality of randomly oriented electrically conductive carbon fibers, a second solid phase is comprised of a 3-dimensional network of a substantially non-conductive porous ceramic material intermingled with said first solid phase, and a third solid phase comprised of a plurality of catalyst particles dispersed on said 3-dimensional network of porous ceramic material;

which process comprises;

a) blending together an effective amount of catalyst particles for an intended reaction and an effective amount of electrically conductive carbon fibers thereby resulting in a blend;

b) mixing at least a portion of said blend with a liquid dispersing agent thereby resulting in a mixture;

c) introducing at least a portion of said mixture and an effective amount of a ceramic sol into a mold;

d) driving-off substantially all of any liquid from the mixture thereby resulting in a dried 3-dimensional porous network of non-conductive ceramic material intermingled with randomly dispersed electrically conductive carbon fibers;

e) calcining dried 3-dimensional porous network of ceramic material and carbon fiber mat of step d) above in an oxygen-containing atmosphere and at a temperature from about 100°

C. to about 500°

C.; and

f) subjecting said calcined 3-dimensional porous network of non-conductive ceramic material/randomly dispersed carbon fibers of step e) above in a hydrogen-containing atmosphere at a temperature from about 200°

C. to about 500°

C. for an effective amount of time to activate substantially all of said catalyst particles, thereby resulting in a catalytic sheet product.

34. The process of claim 33 wherein the carbon fibers are graphitic.

35. The process of claim 33 wherein the catalyst is a methanol reforming catalyst.

36. The process of claim 35 wherein the methanol reforming catalyst contains copper.

37. The process of claim 35 wherein the methanol reforming catalyst contains both copper and zinc.

38. The process of claim 33 wherein the ceramic material is selected from the group consisting of alumina, silica, silica-alumina, titania, and magnesia.

39. The process of claim 38 wherein the ceramic material is alumina.

40. The process of claim 33 which also contains an effective amount of non-conductive ceramic fibers.

41. The process of claim 40 wherein the ceramic fibers are selected from the group consisting of alumina fibers, aluminosilica fibers and aluminoborosilicate fibers.

42. The process of claim 33 wherein there is also present an effective amount of graphite nanofibers.

43. The process of claim 42 wherein the graphitic nanofibers are comprised of graphite platelets that are aligned parallel, perpendicular or at an angle to the longitudinal axis of the nanofiber.