Hydrogen production by an autothermal heat exchanger packed-bed membrane gas reformer

Patent metadata

Field	Value
Publication number	US-9359201-B2
Application number	US-201013387841-A
Country	US
Kind code	B2
Filing date	Aug 2, 2010
Priority date	Aug 3, 2009
Publication date	Jun 7, 2016
Grant date	Jun 7, 2016

Abstract

A process for producing hydrogen from natural gas, said process comprises the steps of: (i) providing an autothermal heat exchanger packed-bed membrane reformer (APBMR) comprising: (a) an elongated external gas oxidation compartment comprising an inlet, an outlet and packed oxidation catalyst particles, said inlet and outlet being located each at one extremity of said external gas oxidation compartment; (b) an elongated internal gas steam-reforming compartment comprising an inlet, an outlet and packed steam-reforming catalyst particles, said inlet and outlet being located each at one extremity of said internal gas steam-reforming compartment; (c) one or more hydrogen-separating membrane(s) positioned in said steam-reforming compartment substantially parallel to the longitudinal axis of said steam-reforming compartment; (d) one insulation layer surrounding said external compartment; and, optionally, (e) one or more elongated internal gas oxidation compartment(s) positioned in said steam-reforming compartment substantially parallel to the longitudinal axis of said gas steam-reforming internal compartment, and comprising an inlet, an outlet and packed oxidation catalyst particles, said inlet and outlet being located each at an extremity of said internal gas oxidation compartment(s); (ii) supplying a mixture comprising said natural gas and air to said gas oxidation compartment(s) of said reformer; and (iii) supplying a mixture comprising said natural gas and water to said gas steam-reforming compartment, wherein the water-to-gas molar ratio is of between 2 and 4, and wherein the water may be pre-vaporized before being supplied into said gas steam-reforming compartment; thereby producing hydrogen suitable to be directly fed into a power generating device (PGD) to generate an electrical power, or to be stored into a suitable container before further use.

First claim

The invention claimed is:

1. A process for producing hydrogen from a natural gas, said process comprising the steps of:
(i) providing an autothermal heat exchanger packed-bed membrane reformer (APBMR) comprising:
(a) an external gas oxidation tube comprising an inlet, an outlet and packed oxidation catalyst particles, said inlet and outlet being located each at one extremity of said external gas oxidation tube;
(b) gas steam-reforming tube disposed within said external gas oxidation tube and substantially parallel to a longitudinal axis of said external gas oxidation tube, said gas steam-reforming tube comprising an inlet, an outlet and packed steam-reforming catalyst particles, said inlet and outlet being located each at one extremity of said internal gas steam-reforming tube;
(c) at least one hydrogen-separating membrane disposed within said steam-reforming tube and substantially parallel to the longitudinal axis of said steam-reforming tube;
(d) one insulation layer surrounding said external tube; and,
(e) at least one internal gas oxidation tube disposed within said steam-reforming tube and substantially parallel to the longitudinal axis of said gas steam-reforming internal tube, and comprising an inlet, an outlet and packed oxidation catalyst particles, said inlet and outlet being located each at an extremity of said at least one internal gas oxidation tube wherein said inlet(s) of said internal gas oxidation tube(s) and said inlet of said external gas oxidation tube are located at opposite extremities, providing opposing flow direction alongside said steam reforming tube, so as to reduce temperature gradient along said steam reforming tube;
(ii) supplying a mixture comprising said natural gas and air to said gas oxidation tube(s) of said reformer; and
(iii) supplying a mixture comprising said natural gas and water to said gas steam-reforming tube, wherein the water-to-gas molar ratio is of between 2 and 4, and wherein the water may be pre-vaporized before being supplied into said gas steam-reforming tube;
thereby producing hydrogen suitable to be directly fed into a power generating device (PGD) to generate an electrical power, or to be stored into a suitable container before further use.

2. A process according to claim 1 , wherein the natural gas is methane.

3. A process according to claim 1 , wherein the autothermal heat exchanger APBMR has a power output of between about 80% and 120% of the PGD power output, an overall methane-to-hydrogen conversion efficiency of between about 55% and about 95%, and is operated at a temperature of between 450° C. and 750° C.

4. A process according to claim 1 , wherein the PGD power output is of between about 0.1 kW and about 10 kW.

5. A process according to claim 1 , wherein the PGD is a polymer electrolyte membrane full cell (PEMFC) stack.

6. A process according to claim 5 , wherein the power efficiency of the PGD is about 0.6 and the autothermal heat exchanger APBMR has a volumetric power density of between about 0.5 kW/L and about 2 kW/L, more preferably between about 0.7 kW/L and about 1.5 kW/L, and more preferably between about 0.9 kW/L to about 1.1 kW/L.

7. A process according to claim 1 , wherein the hydrogen produced comprises less than about 50 ppm of CO, preferably less than about 10 ppm of CO, and more preferably less than 5 ppm of CO.

8. A process according to claim 1 , wherein said autothermal packed-bed membrane reformer is operated in a normal operation mode.

9. A process according to claim 1 , wherein said autothermal packed-bed membrane reformer is operated in a reverse flow operation mode.

10. A process according to claim 1 , wherein said autothermal packed-bed membrane reformer is operated in a counter-current oxidative flow operation mode.

11. A process according to claim 1 , wherein said autothermal packed-bed membrane reformer is operated in a mode selected from normal operation mode, reverse flow operation mode, and counter-current oxidative flow operation mode; and wherein said autothermal packed-bed membrane reformer is additionally operated in a recycling operation mode.

12. An autothermal heat exchanger packed-bed membrane reformer (APBMR) comprising:
(a) an external gas oxidation tube-comprising an inlet, an outlet and packed oxidation catalyst particles, said inlet and outlet being located each at one extremity of said external gas oxidation tube;
(b) a gas steam-reforming tube-disposed within said external gas oxidation tube and substantially parallel to a longitudinal axis of said external gas oxidation tube, said gas steam-reforming tube comprising an inlet, an outlet and packed steam-reforming catalyst particles, said inlet and outlet being located each at one extremity of said internal gas steam-reforming tube;
(c) at least one hydrogen-separating membrane disposed within said steam-reforming tube, and substantially parallel to the longitudinal axis of said steam-reforming tube;
(d) at least one insulation layer surrounding said external tube; and
(e) at least one internal gas oxidation tube disposed within said steam-reforming tube, and substantially parallel to the longitudinal axis of said gas steam-reforming internal tube, and comprising an inlet, an outlet and packed oxidation catalyst particles, said inlet and outlet being located each at one extremity of said at least one internal gas oxidation tube,
wherein said at least one inlet of said at least one internal gas oxidation tube and said inlet of said external gas oxidation tube are located at opposite extremities, providing opposing flow direction alongside said steam reforming tube, so as to reduce temperature gradient along said steam reforming tube.

13. An autothermal heat exchanger APBMR according to claim 12 , wherein the external gas oxidation tube and the internal gas steam-reforming tube are made of two concentric hollow tubes.

14. An autothermal heat exchanger APBMR according to claim 12 , characterized by a length-to-diameter ratio of between about 3 to about 8, wherein said length and said diameter are taken from the external side of the external gas oxidation tube.

15. An autothermal heat exchanger APBMR according to claim 14 , characterized by a length of between about 10 cm and 150 cm, preferably between about 20 cm and 70 cm, and more preferably about 30 cm and 50 cm.

16. An autothermal heat exchanger APBMR according to claim 12 , characterized by an insulation layer having a thickness of about 2 cm to 15 cm.

17. An autothermal heat exchanger APBMR according to claim 12 , wherein the oxidation catalyst particles are spherical pellets of between about 4 mm and 6 mm diameter, and the steam-reforming particles are spherical pellets of between about 3 mm and 5 mm diameter.

18. An autothermal heat exchanger APBMR according to claim 12 , wherein the oxidation catalyst particles are Pt/Al 2 O 3 or Pd/Al 2 O 3 pellets.

19. An autothermal heat exchanger APBMR according to claim 12 , wherein the steam-reforming catalyst particles are Ni/Al 2 O 3 pellets.

20. An autothermal heat exchanger APBMR according to claim 12 , wherein the hydrogen selective membranes are Pd—Ag membranes selected from the group consisting of Pd—Ag foil membranes and Pd—Ag thin films membrane coated on ceramic tubes, stainless steel tubes, or Inconel® tubes.

21. A system for converting natural gas into hydrogen and provide a source of electrical power, said system comprising:
(a) an autothermal heat exchanger packed-bed membrane reformer APBMR according to claim 12 suitable

Assignees

• Simakov David Stanislav A
• Sheintuch Moshe
• Technion Res & Dev Foundation

Inventors

• Simakov David Stanislav A
• Sheintuch Moshe

Classifications

• C01B2203/0844

  the non-combustive exothermic reaction being another reforming reaction as defined in groups C01B2203/02 - C01B2203/0294 · CPC title

• C01B2203/148

  involving a recycle stream to the feed of the process for making hydrogen or synthesis gas · CPC title

• C01B2203/1058

  Nickel catalysts · CPC title

• C01B2203/0233

  the reforming step being a steam reforming step · CPC title

• C01B2203/041

  In-situ membrane purification during hydrogen production · CPC title