초록 ▼

The present invention provides a method of steam reforming a hydrocarbon over a catalyst at short residence times or short contact times. The present invention also provides spinel-containing catalysts. Surprisingly superior results and properties obtained in methods and catalysts of the present i

The present invention provides a method of steam reforming a hydrocarbon over a catalyst at short residence times or short contact times. The present invention also provides spinel-containing catalysts. Surprisingly superior results and properties obtained in methods and catalysts of the present invention are also described.

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We claim: 1. A method of steam reforming, comprising: passing steam and hydrocarbon through a reaction chamber; wherein the reaction chamber comprises a catalyst that has surface active sites comprising a material selected from the group consisting of rhodium, iridium, nickel, palladium, platinum,

We claim: 1. A method of steam reforming, comprising: passing steam and hydrocarbon through a reaction chamber; wherein the reaction chamber comprises a catalyst that has surface active sites comprising a material selected from the group consisting of rhodium, iridium, nickel, palladium, platinum, ruthenium, carbide of group VIb and combinations thereof; wherein the rate of said passing steam and hydrocarbon is controlled such that contact time in the reaction chamber is less than 0.1 seconds; wherein, after passing through the reaction chamber, the hydrocarbon conversion has reached at least 50% of equilibrium conversion. 2. The method of claim 1 wherein the reaction chamber comprises a catalyst that has surface active sites comprising a material selected from the group consisting of rhodium, iridium, nickel, palladium, platinum, and combinations thereof. 3. The method of claim 2 wherein the temperature in the reaction chamber is in the range of 500�� C. to 1000�� C. 4. The method of claim 3 wherein the catalyst comprises: a first porous structure with a first pore surface area and a first pore size of at least 0.1 μm; and a porous interfacial layer with a second pore surface area and a second pore size that is less than the first pore size. 5. The method of claim 4 wherein the porous interfacial layer comprises a spinel. 6. The method of claim 4 wherein the first porous structure comprises a metal foam or metal felt, and the porous interfacial layer comprises alumina. 7. The method of claim 3 wherein the hydrocarbon is converted to at least 90% of equilibrium conversion and hydrogen selectivity is at least 85%. 8. The method of claim 7 wherein the catalyst comprises surface active sites comprising Rh. 9. The method of claim 8 having a hydrogen productivity of between 0.5 and 2 mmol��s-1��cm-3 at a contact time of 10 to 25 msec. 10. The method of claim 8 wherein the hydrocarbon comprises a synthetic fuel made by the Fischer-Tropsch process and wherein, after passing through the reaction chamber, the hydrocarbon conversion has reached at least 70% of equilibrium conversion. 11. The method of claim 3 wherein the H2 productivity is 0.5 to 2 mmol catalyst��s-1��cm-3. 12. The method of claim 3 wherein the catalyst comprises a zirconia support. 13. The method of claim 3 wherein the catalyst is disposed in the reaction chamber such that a gap is provided for flow past the catalyst. 14. The method of claim 13 wherein the reaction chamber is defined by a reaction chamber wall or reaction chamber walls, and wherein the catalyst is in close contact with a reaction chamber wall. 15. The method of claim 2 wherein the catalyst comprises a spinel support. 16. The method of claim 15 wherein the spinel support is in the form of a spinel layer disposed over a high surface area material. 17. The method of claim 16 wherein the high surface area material comprises gamma alumina. 18. The method of claim 15 where the contact time in the reaction chamber is 5 to 100 ms. 19. The method of claim 18 wherein the catalyst possesses a H2 productivity of at least 0.7 mmol��s-1��cm-3. 20. The method of claim 19 wherein the hydrocarbon comprises methane. 21. The method of claim 18 wherein the H2 productivity is 0.5 to 2 mmol catalyst��s-1��cm-3. 22. The method of claim 15 where the hydrocarbon comprises methane. 23. The method of claim 15 wherein the temperature in the reaction chamber is at least 650�� C. 24. The method of claim 15 wherein the hydrocarbon consists essentially of C1-C10 alkanes; wherein hydrocarbon equilibrium conversion is at least 90% and H2 selectivity is at least 60%. 25. The method of claim 24 wherein hydrocarbon equilibrium conversion is at least 99%, wherein the surface active sites comprise Rh, and wherein the reaction is conducted at a temperature in the range of 650-885�� C. 26. The method of claim 24 wherein the hydrocarbon consists essentially of methane; wherein hydrocarbon equilibrium conversion is at least 99% and H2 selectivity is 100%. 27. The method of claim 2 where the contact time in the reaction chamber is 10 to 25 ms. 28. The method of claim 2 where the hydrocarbon consists essentially of methane. 29. The method of claim 2 wherein the absolute conversion is at least 90%. 30. The method of claim 29 wherein H2 selectivity is at least 95%. 31. The method of claim 2 wherein the equilibrium conversion is at least 95%. 32. The method of claim 2 wherein H2 selectivity is at least 85%. 33. The method of claim 1 wherein the catalyst comprises a zirconia support. 34. The method of claim 1 wherein the catalyst has a pore volume of 30 to 95% and at least 50% of the catalyst's pore volume is composed of pores in the size range of 0.3 to 200 microns. 35. The method of claim 1 wherein H2 selectivity is at least 60%. 36. The method of claim 1 wherein the catalyst has a corrugated form. 37. The method of claim 1 wherein the hydrocarbon consists essentially of C1-C10 alkanes; wherein hydrocarbon equilibrium conversion is at least 90% and H2 selectivity is at least 60%. 38. The method of claim 37 wherein hydrocarbon equilibrium conversion is at least 99%, and wherein the reaction is conducted at a temperature in the range of 650-885�� C. 39. The method of claim 37 wherein the hydrocarbon consists essentially of methane; wherein hydrocarbon equilibrium conversion is at least 99% and H2 selectivity is 100%. 40. A method of steam reforming, comprising: passing steam and hydrocarbon through a reaction chamber; wherein the reaction chamber comprises a catalyst; wherein the catalyst comprises: a first porous structure with a first pore surface area and a first pore size of at least 0.1 μm; a porous interfacial layer with a second pore surface area and a second pore size that is less than the first pore size; and a catalyst metal. 41. The method of claim 40 wherein the rate of said passing steam and hydrocarbon is controlled such that residence time in the reaction chamber is less than about 0.1 seconds; wherein at least 50% of said hydrocarbon has been converted to products after passing through the reaction chamber. 42. The method of claim 41 wherein the catalyst that has surface active sites comprising a material selected from the group consisting of rhodium, iridium, nickel, palladium, platinum, and combinations thereof. 43. The method of claim 42 wherein the absolute conversion is at least 90%. 44. The method of claim 41 wherein the porous interfacial layer comprises a material selected from the group consisting of alumina and spinel. 45. The method of claim 44 where the porous interfacial layer comprises spinel or zirconia and the temperature in the reaction chamber is in the range of 500��to 1000�� C. 46. The method of claim 45 wherein the equilibrium conversion is at least 90%. 47. The method of claim 46 wherein the contact time is 5 to 100 ms. 48. The method of claim 41 where the hydrocarbon comprises methane. 49. The method of claim 41 wherein the porous interfacial layer comprises zirconia. 50. The method of claim 40 wherein the rate of said passing steam and hydrocarbon is controlled such that contact time in the reaction chamber is in the range of 5 to 100 milliseconds; and wherein, after passing through the reaction chamber, the hydrocarbon conversion has reached at least 50% of equilibrium conversion. 51. The method of claim 50 wherein H2 selectivity is at least 50%. 52. The method of claim 40 wherein the catalyst is disposed in the reaction chamber such that a gap is provided for flow past the catalyst. 53. A method of steam reforming, comprising: passing steam and hydrocarbon through a reaction chamber; wherein the reaction chamber comprises a catalyst; wherein the catalyst comprises: catalyst has a pore volume of 30 to 95% and at least 50% of the catalyst's pore volume is composed of pores in the size range of 0.3 to 200 microns; and a catalyst metal. 54. The method of claim 53 wherein the catalyst has a hydrogen productivity of at least 0.7 mmol��s-1��cm3. 55. The method of claim 54 wherein H2 selectivity is at least 60%. 56. The method of claim 53 wherein the catalyst comprises a spinel coating. 57. The method of claim 56 wherein the spinel coating is disposed over a high surface area material. 58. The method of claim 53 wherein the hydrocarbon has a contact time of 5-100 ms with the catalyst.