WO2003093536A2

WO2003093536A2 - Hydrogen generation

Info

Publication number: WO2003093536A2
Application number: PCT/GB2003/001933
Authority: WO
Inventors: Kevin Kendall; Gary John Saunders; Christian Mallon
Original assignee: Hydrogen Advance Limited
Priority date: 2002-05-02
Filing date: 2003-05-02
Publication date: 2003-11-13
Also published as: AU2003229987A8; GB0210075D0; AU2003229987A1; WO2003093536A3

Abstract

An apparatus (2) is provided to generate hydrogen and includes a region (6) and a partition (10) including electrolyte material that is conductive of oxygen ions. The electrolyte material is provided with a non-metallic electron conducting path. In the apparatus (2) at least a portion of the partition (10) is in the region (6). The apparatus further comprises steam generating means (14) to supply steam to the first side of the portion and the steam is in a dissociated state comprising hydrogen and oxygen and means to ionise the dissociation oxygen into oxygen ions. Means are provided to cause the oxygen ions to pass through the partition (10) to the second side leaving at the first side dissociation hydrogen as residual hydrogen and means are provided to collect residual hydrogen. The apparatus (2) is arranged for operations where the temperature of the region (6) is at least 700°C when the apparatus (2) is in use.

Description

HYDROGEN GENERATION

This invention concerns a method of generating hydrogen, and also concerns apparatus to generate hydrogen, and further concerns hydrogen generated by said method and/or by said apparatus, and additionally concerns a fuel cell fuelled by the generated hydrogen.

Pure or substantially pure hydrogen will be needed in large quantities when the hydrogen economy becomes established. Fuel cells especially need pure hydrogen because of their sensitivity to impurities such as carbon monoxide in the fuel stream.

Hydrogen is conventionally produced from hydrocarbons such as natural gas by a reforming process whereby steam, CO₂ or other reactant is contacted with the fuel to produce hydrogen and carbon monoxide. The problem is that this process does not give pure hydrogen. This can only be obtained by further shift reaction with water to convert the CO into hydrogen, followed by further processing to remove residual CO and subsequent clean-up to reduce CO to around lppm. These extra steps are expensive, and add complexity and sluggishness to the overall hydrogen generation.

Another method for producing pure hydrogen is electrolysis of water. Electrical current is passed through an ionised water composition and hydrogen is separated at one electrode and oxygen at the other. There are two problems with this method when operated near ambient temperature :- the first is that expensive catalysts are generally needed to enhance the reaction rate; the second is that the process requires a large ΔG to generate hydrogen where ΔG is the change in Gibb's (free energy) function. US 3 635 812 provides a solid oxygen ion electrolyte cell for the dissociation of steam. The cell is tubular with porous nickel-zirconia electrodes and a solid oxygen electrolyte formed from yttria-stabilised zirconia sintered with iron oxide additive. The electrodes are connected to a DC electrical power supply. In operation, steam at 800 °C is supplied to the cathode inside the tube. At this temperature the water vapour dissociates into hydrogen and oxygen. At the cathode, each oxygen atom accepts two electrons to become an oxygen ion which is then transported across the electrolyte. At the anode, the oxygen-ions release electrons, which return to the power supply making oxygen atoms available at the anode. A reducing gas mixture of CO and H₂ is supplied to the anode to remove the oxygen produced. This document also discloses providing nickel conducting paths through the electrolyte between the anode and cathode which allows the cell to operate without an external source of power.

A problem with the arrangement disclosed in US 3 635 812 is that it cannot be operated at a high temperature. Generally the higher the temperature, the more efficient the cell becomes. However at a temperature above 1100°C nickel sinters, which would destroy a cell.

A solution to these problems has been sought.

A new process has now been devised by which pure or substantially pure hydrogen may be produced in what may be regarded as effectively one step.

According to a first aspect of the invention a method of producing hydrogen includes the steps of: providing a partition comprising electrolyte material, said partition having a thickness between opposite first and second sides of the partition and wherein oxygen ions can pass through the thickness of the partition in which said material provides obstruction to passage of non-ionised oxygen and species other than oxygen, at least a portion of the partition being in a region at a temperature of at least substantially 700°C; providing at said portion at said first side steam dissociated into hydrogen and oxygen (hereinafter referred to as dissociation hydrogen and dissociation oxygen); separating the dissociation oxygen from the dissociation hydrogen to leave residual dissociation hydrogen which is collected; wherein a procedure to separate said dissociation hydrogen from said dissociation oxygen includes ionising said dissociation oxygen into oxygen ions and causing the oxygen ions to pass through the partition to said second side; and wherein said partition has non-metallic electron conducting paths.

According to a second aspect of the invention apparatus to generate hydrogen includes: a region; a partition including electrolyte material; said partition having a thickness between opposite first and second sides of the partition; said electrolyte material being conductive of oxygen ions whereby an oxygen ion can pass through the thickness of the partition in which said material provides obstruction to passage of non-ionised oxygen and species other than oxygen; said electrolyte material being provided with a non-metallic electron conducting path whereby an electron can pass through the thickness of the partition; at least a portion of the partition being in said region; the apparatus being arranged for operations such that the temperature of said region is at least substantially 700 °C when the apparatus is in use; steam generating means to supply steam to the first side of the portion at said portion whereat, when said apparatus is in use, said steam is to be in a dissociated state comprising hydrogen and oxygen (hereinafter referred to as dissociation hydrogen and dissociation oxygen) ; means to ionise aforesaid dissociation oxygen into oxygen ions; means to be used, when the apparatus is in use, to cause said oxygen ions to pass through the partition to said second side leaving at said first side aforesaid dissociation hydrogen as residual hydrogen; and means to collect said residual hydrogen.

Said electrolyte material may be or include solid oxide electrolyte which conducts oxygen ions. The electrolyte material may prevent, or provide obstruction to, passage or conduction therethrough of species other than oxygen such as non-ionised oxygen or other atoms or molecules which are not oxygen and which are ionised or non-ionised. Said electrolyte material may comprise cubic zirconium oxide, for example stabilised cubic zirconium oxide and/or bismuth oxide and/or cerium oxide and/or other oxygen ion conducting materials, for example certain rare earth oxides .

The non-metallic electron conducting path may be provided by using zirconia in the electrolyte material and operating the apparatus or the method at a temperature above substantially 1300 °C. Under these conditions, zirconia conducts electrons. Alternatively the non-metallic electron conducting path may be provided by doping the electrolyte material with a dopant which conducts electrons at a temperature above substantially 700 °C. A suitable dopant is ytterbium oxide, cerium oxide, praseodymium oxide, and/or hafnium oxide. The dopant may be included in an amount of up to 10% by weight. The electrolyte is preferably free from metallic additives, particularly metallic additives which provide an electron conducting path.

By including an electron conducting path, the electrolyte is short-circuited and can operate without application of an externally applied electrical potential. Since the electron conducting path is non-metallic, the apparatus can be operated at much higher temperatures where the ΔG is less.

Said region may be arranged to be at a temperature of substantially 700 °C or higher for example at least substantially 800 °C or higher. Said temperature may be at least substantially 1300°C or higher, for example at least substantially 1500°C or higher. For example said temperature may be in a range of substantially 700 °C to substantially 2000 °C, or of substantially 800 °C to substantially 2000°C, or of substantially 1300°C to substantially 2000°C, or of substantially 1500°C to substantially 2000°C.

Said region may be a furnace chamber. Said furnace chamber may be provided with heating means, for example electrical heating means, which may be controlled.

Said partition may be arranged for ionising oxygen at or adjacent to said first side. Said partition may be provided with catalyst means for use in ionising oxygen and/or dissociating oxygen and/or transmitting oxygen, at or adjacent to said first side.

Said partition may be arranged for de-ionising oxygen ions at or adjacent to said second side. Said partition may be provided with catalyst means for use in de-ionising ionised oxygen and/or combining de-ionised oxygen and/or transmitting de-ionised oxygen, at or adjacent to said second side.

Means may be provided for collecting water formed from a combination of dissociation hydrogen and dissociation oxygen from said first side. Said water may be supplied for production of said steam, for example by said steam generation means.

Arrangement may be provided to promote or encourage oxygen ion flow through the partition.

Said arrangement may comprise providing an electric field across the partition. For example a cathode may be provided at said first side and an anode may be provided at said second side. A DC potential may be applied to the cathode and anode. Said cathode and/or said anode may be a layer of aforesaid catalyst means.

Said arrangement may comprise creating or encouraging provision of a chemical potential or oxygen gradient across the partition. This may be encouraged or promoted by removal of oxygen from the vicinity of the second side. Oxygen may be so removed by reacting or combusting it in said region with a fuel. Preferably said reacting or combusting is an exothermic reaction, preferably a highly exotherthermic reaction providing heat to heat said region. Products of combustion from said region may be used, for example in heat exchange means, to provide heat used in aforesaid provision of steam, for example in said steam generating means. Said fuel may comprise at least one hydrocarbon, and/or a biofuel, and/ or carbon monoxide, and/or carbon, and/or ammonia, and/or hydrazine. Said arrangement may comprise providing high pressure at said first side to encourage oxygen ion flow from the first side through the partition.

Said arrangement may comprise withdrawing oxygen from a vicinity of said second side by application of suction, for example by pump means.

An external electron conductor arrangement may be provided for conducting electrons from the second side to the first side, wherein said conductor arrangement comprises at least one specifically provided electron path additional to said electrolyte material. Said conductor arrangement may comprise a coil. Said conductor arrangement may comprise metal wire, strips, or rods.

Said electrolyte material may be such that free electrons may pass therethrough from the second side of the partition to said first side when the material is at a temperature of at least substantially 1300°C or higher.

Said partition may be a tubular wall, and one said side may be an external surface of the tube and the other said side may be an internal surface of the tube. Said region may have a plurality of said tubes therein. Said tubes may be narrow, for example having an external diameter of substantially 5 mm or preferably less, more preferably less than 2 mm, most preferably less than 1 mm. Tube wall thickness may be substantially 0.1 mm or preferably less, or more preferably less than 0.5 mm. Said first side may be an inner surface of a said tube, and said second side may be an outer surface of the tube. A plurality of said tubes may be supplied with steam by a first common manifold, and/or said tubes may supply hydrogen product to a second common manifold.

A problem with using zirconia in the electrolyte is that it has a high expansion coefficient. One advantage of the apparatus according to the invention is that the tubes can be made with a relatively narrow external diameter and wall thickness minimising the problems caused by using zirconia. Such problems include temperature gradients within the tubes due to part of the tubes being within said region and part of the tubes being between said region and the manifold possibly resulting in the tubes becoming cracked. Generally the larger the tubes are, the more of a problem this becomes.

According to a third aspect of the invention there is provided hydrogen generated by a method according to the first aspect of the invention.

According to a fourth aspect of the invention there is provided hydrogen generated by use of an apparatus according to the second aspect of the invention.

According to a fifth aspect of the invention there is provided a fuel cell fuelled by hydrogen produced according to the third or fourth aspect of the invention.

The invention will now be further described, by way of example, with reference to the accompanying drawings, in which :-

Figure 1 diagrammatically illustrates apparatus to generate hydrogen, said apparatus being formed according to the second aspect of the invention and being suitable for use in performance of the method of producing hydrogen according to the first aspect of the invention;

Figures 2 to 4 are respective illustrations, similar to Figure 1 , of respective modifications of the apparatus in Figure 1, each modification being suitable for use in performance of the method according to the first aspect of the invention;

Figure 5 is a diagrammatic cross-sectional view of a fragment of a tube of electrolyte material, which tube may be used in any of the apparatus in Figures 1 to 4; and

Figure 6 diagrammatically illustrates a battery of fuel cells each being supplied with hydrogen fuel produced by apparatus according to the second aspect of the invention performing the method according to the first aspect.

In the following description the same references identify similar or comparable parts.

With reference to Figure 1 a hydrogen generator is indicated at 2 and comprises a furnace 4 comprising a furnace chamber 6 surrounded by furnace walls 8 comprising heat insulation material. A plurality of tubes 10 (at least some of which tubes may be of substantially circular cross- section and at least some of which tubes may be substantially parallel) may extend through the furnace chamber 6.

Each tube 10 has a tube wall forming a partition between the interior and exterior of the tube, the tube wall comprising an electrolyte membrane material which is a conductor of oxygen ions but obstructs passage of non-ionised oxygen and other species or matter through the tube wall. The tubes 10 may be formed of solid oxide electrolyte material known in the solid oxide fuel cell art, which electrolyte material may be of a ceramic nature, for example, the tubes 10 may comprise zirconium oxide, for example stabilised cubic zirconia, and/or bismuth oxide and/or cerium oxide and the tube wall material may be doped whereby the doped material is an electrolyte material which conducts oxygen ions; a suitable dopant may be yttrium oxide.

The tube wall material may be further doped with a dopant which provides a non-metallic electron conducting path such as ytterbium oxide, cerium oxide, praseodymium oxide, and/or hafnium oxide in an amount of up to 10% by weight. Such a dopant is included where the electrolyte material does not include zirconia and is not intended for operation at a temperature above substantially 1300°C.

Advantageously the wall of each tube 10 is as thin as possible consistent with the tube remaining intact during use in the operational conditions chosen; for example in the process discussed with reference to Figure 1 each tube 10 may have an external diameter of substantially 2.0 mm or preferably less and a wall thickness of substantially 0.1 mm (100 μm) or preferably less. Narrow tubes 10 allow the furnace chamber 6 to be packed with a relatively large surface area of the electrolyte membrane material.

At one end, the tubes 10 are connected to a steam manifold 12 supplied with steam by a steam generator 14. At their other ends, the tubes are connected to an outlet or collector manifold 16 from which hydrogen from the process is output through outlet 18. Condensed water from the process is output through outlet 20 from the manifold 16 and supplied on line 22 to the steam generator 14, which may be additionally supplied with make-up water as indicated by arrow 24.

The furnace chamber 6 is raised to a relatively high temperature, for example to at least substantially 700 °C or higher and more preferably to at least substantially 800°C or higher, for example to a temperature in a range of substantially 800°C to substantially 2000°C. The furnace 6 may be heated, or at least heated initially, by heating means 26 which may provide a controlled input of heat whereby the furnace chamber is raised to a desired temperature and/or operated at a desired controlled predetermined temperature. For example the heating means 26 may comprise an electric heater supplied with a suitably controlled supply of power by a supply and control system 28. Within the tubes 10, and essentially within those parts of the tubes exposed to the temperature of the chamber 6, the steam from manifold 12 dissociates into hydrogen and oxygen (herein called dissociation hydrogen and dissociation oxygen) . The dissociation oxygen may be molecular or atomic oxygen, but if in the molecular state some will dissociate into atomic oxygen. At or adjacent to an inner surface of each tube 10 oxygen atoms become ionised and oxygen ions pass through the membrane wall 10 to the exterior of the tube. At or adjacent to the exterior of each tube 10 oxygen ions are de- ionised to resultant oxygen. Means is provided as will be discussed below to consume or carry off the resultant oxygen. From the membrane tubes 10, the dissociation hydrogen is supplied to the manifold 16 and can leave as substantially pure hydrogen through outlet 18. This hydrogen is the product. Non-ionised dissociation oxygen from within the tubes 10 can recombine with some of the dissociation hydrogen to form water which is condensed and output from the water outlet 20 of manifold 16.

At high temperatures within the chamber 6, for example at about or above substantially 1300°C the electrolyte membranes 10 can conduct electrons through the tubular wall in the opposite direction to oxygen ion flow. Thus on oxygen ions becoming de-ionised at or adjacent to the exteriors of the tubes 10, the detached or free electrons can return to the inside surfaces of the tubes to participate in ionising dissociation oxygen.

To promote ionisation of the dissociation oxygen at or adjacent to an inner surface of a said tubular electrolyte membrane 10 and to promote de-ionisation at or adjacent to the outer surface of the tube both surfaces may be coated with a respective thin pervious coating, as indicated illustratively at 30 and 32 of one or more suitable known catalysts which may be known from the solid oxide fuel cell art. For example, the outer layer or coating 30 may be regarded in the operation discussed below with reference to Figure 2 as an anode and may comprise a metal cermet material. Said metal cermet material may comprise one or more of nickel, cerium, zirconium and/or oxides thereof, for example ceria or zirconia, and/or other catalytic and/or metallic additives. In the operation discussed below with reference to Figure 2, the inner layer or coating 32 may be regarded as a cathode. For example this inner coating 32 may comprise a lanthanum strontium manganite material and/or other mixed conducting species.

If desired, each tubular electrolyte membrane 10 may be provided with one or more external electron conducting paths whereby electrons appearing at an outer surface of said tube 10 consequential to de-ionising of oxygen ions can be conducted back to the inner surface of the tubes to participate in the ionising of the dissociation oxygen. For example, in Figure 5 the electrolyte membrane tube 10 has a coil of wire or other conductor wound around its exterior surface and a length 36 of this wire or conductor extends from the coil and passes around an end of the tube to make conducting contact with an inner surface of the tube where the latter ionises the dissociation oxygen, for example at catalyst inner layer 32. Thus free electrons at the outside of the tube 10 can be captured by the coil 34 and conducted back to the inside of the tube.

A number of procedures may be used to encourage flow of oxygen ions through the walls of the tubes 10. For example in Figure 2, the outer and inner catalyst coatings 30 and 32 are respectively connected by conductors 35 and 37 to the positive and negative sides of a source of DC electrical power 39 applying a potential so that the outer coating 30 is an anode and the inner coating 32 is a cathode and an electric field between the anode and cathode of a tube 10 drives the oxygen ions through the electrolyte membrane and produces an enhanced production and flow of hydrogen product along the tube. Also oxygen ion flow can be encouraged by creating a chemical or oxygen potential across the membrane from inside each tube 10 to its exterior. This may be done by chemically or mechanically removing oxygen from the environment surrounding the tubes 10. The chemical removal of the oxygen may be by combustion or comparable exothermic reaction, preferably a highly exothermic reaction. For example a suitable fuel may be supplied as indicated by arrow 40 along inlet conduit 42 to the furnace chamber 6 which is a combustion chamber in which the fuel combusts with the oxygen and wherein the hot products of combustion heat the sections of the tubes 10 within the furnace chamber and leave via outlet or flue conduit 44 as exhaust gases. The conduit 44 supplies the hot products of combustion to an inlet 46 of a heater or heat exchanger providing steam generating heat in the steam generator 14 from which an outlet 48 carries off the exhaust gases after steam generating heat has been extracted. Suitable fuel which may be supplied to combustion chamber 6 through inlet 42 may be one or more hydrocarbons, biofuel, carbon dioxide, carbon, ammonia, or hydrazine. For example, if the hydrocarbon fuel is methane the exothermic combustion reaction would be:-

2CH₄ + 30₂ -» 2CO + 4H₂O If the reaction within combustion chamber 6 is highly exothermic, there may be no need to continue using heating means 26 once the process is running.

In the procedure described above with reference to Figure 1 the overall effect is to produce substantially pure hydrogen product in what is effectively a one step process. Benefits of the procedure are: (1) a single stage process;

(2) pure hydrogen product with no carbon content;

(3) no expensive precious metal catalysts required;

(4) good kinetics at high temperature; and (5) low ΔG at elevated temperature.

Figure 6 shows the hydrogen generator 2 supplying the hydrogen product on line 18 as fuel to a fuel cell, or more specifically to a battery 50 of fuel cells.

In Figure 3, the furnace chamber 6 has an outlet conduit 44A. Oxygen ions may be induced to pass through the walls of the membrane tubes 10 from inside to the outside of the tubes by the high pressure of the steam supplied to the tubes. In this case heating of the chamber 6 may be by the heating means 26 and hot gaseous products, for example hot oxygen, may leave the chamber 6 through the conduit 44A and may be used to provide heat for steam generation in steam generator 14, for example, as aforesaid.

In Figure 4, the conduit 44A is provided with suction pump means 52. In this instance suction is applied to the furnace chamber 6 to encourage the flow of oxygen ions through the membrane walls to the exterior of the tubes 10. Again hot gaseous products from the conduit 44A can be used in the steam generator 14 to provide heat for steam generation.

Claims

1. Apparatus to generate hydrogen includes: a region; a partition including electrolyte material; said partition having a thickness between opposite first and second sides of the partition; said electrolyte material being conductive of oxygen ions whereby an oxygen ion can pass through the thickness of the partition in which said material provides obstruction to passage of non-ionised oxygen and species other than oxygen; said electrolyte material being provided with a non-metallic electron conducting path whereby an electron can pass through the thickness of the partition; at least a portion of the partition being in said region; the apparatus being arranged for operations such that the temperature of said region is at least substantially 700°C when the apparatus is in use; steam generating means to supply steam to the first side of the portion at said portion whereat, when said apparatus is in use, said steam is to be a dissociated state comprising hydrogen and oxygen (hereinafter referred to as dissociation hydrogen and dissociation oxygen); means to ionise aforesaid dissociation oxygen into oxygen ions; means to be used, when the apparatus is in use, to cause said oxygen ions to pass through the partition to said second side leaving at said first side aforesaid dissociation hydrogen as residual hydrogen; and means to collect said residual hydrogen.

2. The apparatus according to Claim 1 wherein the electrolyte material is or includes solid oxide electrolyte which conducts oxygen ions.

3. The apparatus according to Claim 1 or Claim 2 wherein the electrolyte material comprises cubic zirconium oxide.

4. The apparatus according to any preceding claim wherein the non- metallic electron conducting path is provided by using zirconia in the electrolyte material and operating the apparatus or the method at a temperature above substantially 1300°C.

5. The apparatus according to any one of Claims 1 to 3 wherein the non-metallic electron conducting path is provided by doping the electrolyte material with a dopant which conducts electrons at a temperature above substantially 700°C.

6. The apparatus according to Claim 5 wherein the dopant is ytterbium oxide, cerium oxide, praseodymium oxide, and/or hafnium oxide.

7. The apparatus according to Claim 5 or Claim 6 wherein the dopant is included in an amount of up to 10% by weight.

8. The apparatus according to any preceding claim wherein the region is arranged to be at a temperature of substantially 700°C to substantially 2000°C.

9. The apparatus according to any preceding claim wherein the region is a furnace chamber.

10. The apparatus according to Claim 9 wherein the furnace chamber is provided with heating means which is controlled.

11. The apparatus according to any preceding claim wherein means are provided for collecting water formed from a combination of dissociation hydrogen and dissociation oxygen from said first side.

12. The apparatus according to any preceding claim wherein an arrangement is provided to promote or encourage oxygen ion flow through the partition.

13. The apparatus according to Claim 12 wherein the arrangement comprises providing an electric field across the partition.

14. The apparatus according to Claim 12 wherein the arrangement comprises creating or encouraging provision of a chemical potential or oxygen gradient across the partition.

15. The apparatus according to Claim 12 wherein the arrangement comprises providing high pressure at said first side to encourage oxygen ion flow from the first side through the partition.

16. The apparatus according to Claim 12 wherein the arrangement comprises withdrawing oxygen from a vicinity of said second side by application of suction.

17. The apparatus according to any preceding claim wherein an external electron conductor arrangement is provided for conducting electrons from the second side to the first side.

18. The apparatus according to Claim 17 wherein said conductor arrangement comprises at least one specifically provided electron path additional to said electrolyte material.

19. The apparatus according to any preceding Claim wherein the electrolyte material is such that free electrons can pass there through from the second side of the partition to said first side when the material is at a temperature of at least substantially 1300°C or higher.

20. The apparatus according to any preceding claim wherein the partition is a tubular wall and one said side is an external surface of the tube and the other side is an internal surface of the tube.

21. The apparatus according to Claim 20 wherein the tube region has a plurality of said tubes therein.

22. A method of producing hydrogen includes the steps of: providing a partition comprising electrolyte material, said partition having a thickness between opposite first and second sides of the partition and wherein oxygen ions can pass through the thickness of the partition in which said material provides obstruction to passage of non-ionised oxygen and species other than oxygen, at least a portion of the partition being in a region at a temperature of at least substantially 700°C; providing at said portion at said first side steam dissociated into hydrogen and oxygen (hereinafter referred to as dissociation hydrogen and dissociation oxygen) ; separating the dissociation oxygen from the dissociation hydrogen to leave residual dissociation hydrogen which is collected; wherein a procedure to separate said dissociation hydrogen from said dissociation oxygen includes ionising said dissociation oxygen into oxygen ions and causing the oxygen ions to pass through the partition to said second side; and wherein said partition has non-metallic electron conducting paths.

23. Use of a method according to Claim 22 to generate hydrogen.

24. Use of an apparatus according to any one of Claims 1 - 21 to generate hydrogen.

25. A fuel cell fuelled by hydrogen produced according to Claim 23 or 24.

26. Apparatus to generate hydrogen substantially as described herein and with reference to the drawings.

27. A method of producing hydrogen substantially as described herein and with reference to the drawings.

28. Use of apparatus to generate hydrogen substantially as described herein and with reference to the drawings.

29. Use of a method of producing hydrogen substantially as described herein and with reference to the drawings.

30. A fuel cell substantially as described herein and with reference to the drawings.