Hydrogen Production

• US 20080159938A1
• Filed: 01/23/2006
• Published: 07/03/2008
• Est. Priority Date: 02/10/2005
• Status: Active Grant

• Current Assignee: Bestrong International Limited
• Original Assignee: Elektrowatt AG (Siemens AG)
• Inventors: Hammel, Ernst, Mauthner, Klaus
• Granted Patent: US 8,034,321 B2
• Time in Patent Office: Days
• US Class Current: 423/246
• CPC Class Codes: B01J 23/755 Nickel
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: B82Y 40/00 Manufacture or treatment of nanostructures
• CPC Class Codes: C01B 2203/0233 the reforming step being a steam reforming step
• CPC Class Codes: C01B 2203/0277 containing a catalytic decomposition step
• CPC Class Codes: C01B 2203/1058 Nickel catalysts
• CPC Class Codes: C01B 2203/141 At least two reforming, decomposition or partial oxidation steps in parallel
• CPC Class Codes: C01B 3/26 using catalysts
• CPC Class Codes: C01B 3/382 Multi-step processes
• CPC Class Codes: C01B 32/16 Preparation
• CPC Class Codes: C01B 32/18 Nanoonions; Nanoscrolls; Nanohorns; Nanocones; Nanowalls
• CPC Class Codes: Y02P 20/129 Energy recovery, e.g. by cogeneration, H2recovery or pressure recovery turbines
• CPC Class Codes: Y02P 20/52 using catalysts, e.g. selective catalysts

Abstract

A method is described for producing a hydrogen-containing gas mixture from a suitable hydrocarbon-containing feed gas in a reformer, wherein at least part of the feed gas is diverted before it enters the reformer and is supplied to at least one secondary reformer, and wherein the feed gas is contacted with a nanostructured catalyst in the secondary reformer and the substantially CO and CO₂-free exhaust gases of the secondary reformer are either combined with the hydrogen-containing gas mixture which escapes the reformer or introduced into the reformer. Furthermore, there is described the use of this method for producing high-quality soots, nanoonions, nanohorns, nanofibers and/or nanotubes which adhere to the catalyst, and a device for producing a hydrogen-containing gas mixture from a suitable feed gas in a reformer (1) which comprises a supply line (a) with a superheated-vapor line (b) joining said supply line, and a discharge line (c).

Claims

1. Method for producing a hydrogen-containing gas mixture from a suitable hydrocarbon-containing feed gas in a reformer, comprising:

diverting at least part of the feed gas before it enters the reformer and is supplied to at least one secondary reformer, wherein the feed gas is contacted with a nanostructured catalyst in the secondary reformer and the substantially CO and CO2-free exhaust gases of the secondary reformer are either combined with the hydrogen-containing gas mixture which escapes the reformer or is introduced into the reformer.

2. Method according to claim 1, wherein the exhaust gases of the secondary reformer are preheated before they enter the reformer.

3. Method according to claim 1, wherein the exhaust gases of the reformer are post-combusted for removing carbon monoxide.

4. Method according to claim 3, wherein the exhaust gases of the secondary reformer are combined with the hydrogen-containing gas mixture which escapes the reformer and cooled down before post-combustion.

5. Method according to claim 1, wherein the nanostructured catalyst is arranged on a carrier.

6. Method according to claim 5, wherein the carrier is a two-dimensional carrier.

7. Method according to claim 5, wherein the carrier comprises particle-shaped ceramic bodies or particle-shaped glass bodies.

8. Method according to claim 1, wherein in the secondary reformer the nanostructured catalyst is continuously fed in and fed out, optionally as a function of the hydrogen content in the exhaust gas.

9. Method according to claim 8, wherein the nanostructured catalyst and the feed gas in the secondary reformer are guided in co-current flow.

10. Method according to claim 8, wherein the nanostructured catalyst and the feed gas in the secondary reformer are guided in counter-current flow.

11. Method according to claim 1, wherein the feed gas in the secondary reformer is contacted with the nanostructured catalyst at a temperature in the range of from 300°

C. to 1400°

C.

12. Method according to claim 11, wherein the feed gas in the secondary reformer is contacted with the nanostructured catalyst at a temperature in the range of from 400°

C. to 700°

C.

13. Method according to claim 1, wherein the catalyst is selected from the group consisting of group-VIII transition elements.

14. Method according to claim 13, wherein the catalyst is a composite catalyst which comprises a member selected from the group consisting of alkaline earth metal oxides, silicon, silicon oxide, and mixtures thereof.

15. Method according to claim 13, wherein nickel and/or iron is/are used as catalyst.

16. Method according to claim 1, wherein the catalyst in the secondary reformer is continuously or discontinuously fed out and separated from adhering carbon compounds.

17. Method according to claim 16, wherein the catalyst is mechanically separated from adhering carbon compounds by scraping off or in a cyclone.

18. Method according to claim 16, wherein the catalyst is chemically separated from adhering carbon compounds by an etching process.

19. Method according to claim 16, wherein the catalyst is physically separated from adhering carbon compounds by high-temperature treatment, baking out, inductively, by RF or HF.

20. Method according to claim 1, wherein natural gas is used as feed gas.

21. Method according to claim 1, wherein an optionally pre-purified biogas is used as feed gas.

22. Method according to claim 1, wherein part of the feed gas is used as heating gas for heating the reformer and/or secondary reformer.

23. Method according to claim 1, wherein the secondary reactor is at least partially heated by the waste heat of the reformer.

24. A method according to claim 1, for producing high-quality technical soots, nanoonions, nanohorns, nanofibers and/or nanotubes which adhere to the catalyst.

25. Device for producing a hydrogen-containing gas mixture from a suitable feed gas in a reformer, said reformer comprising a supply line with a superheated-steam line joining said supply line, and a discharge line, wherein at least part of the feed gas, before it enters the reformer, is diverted via a first line provided in the flowing direction in front of the junction of the superheated-vapor line, and is supplied to at least one secondary reformer, wherein the feed gas in the secondary reformer is contacted with a nanostructured catalyst and the exhaust gases of the secondary reformer are either combined with the hydrogen-containing gas mixture, which escapes the reformer, in line via a second line or are introduced into the reformer via a third line.

26. Device according to claim 25, wherein a heat exchanger is additionally arranged in the reformer, wherein the exchanger can optionally be connected to the third line.

27. Device according to claim 25, wherein a heat exchanger connected with the superheated steam line via a line is additionally arranged in the reformer, and the exhaust gases of the secondary reformer are fed into the vapor supply of the heat exchanger via a fourth line.

28. Device according to claim 27, wherein the exhaust gases of the reformer are guided into a heat exchanger via the discharge line and the arising vapor is fed into the vapor supply of the heat exchanger.

29. Device according to claim 28, wherein the exhaust gases escaping the heat exchanger are guided into a combustion reactor via a line for removing carbon monoxide.

30. Device according to claim 25, wherein the secondary reformer comprises a supply and discharge arrangement for continuous feed-in and feed-out of nanostructured catalyst.

31. Device according to claim 25, wherein part of the feed gas is diverted from the first line via a fifth line and is supplied to the reformer and/or the secondary reformer as heating gas via the fifth line.

32. Device according to claim 25, wherein the reformer and the secondary reformer are connected by a heat-conducting element.

33. Using a method for producing a hydrogen-containing gas mixture from a suitable carbon-containing feed gas, wherein at least part of the feed gas is supplied to a secondary reformer wherein the feed gas in the secondary reformer is contacted with a nanostructured catalyst, and the substantially CO and CO2-free exhaust gases of the secondary reformer are, in addition, optionally CO2 reduced, for producing high-quality technical soots, nanoonions, nanohorns, nanofibers and/or nanotubes which adhere to the catalyst, and for using them as substitute for industrial soot.