GB2559953A

GB2559953A - An apparatus for generating hydrogen

Info

Publication number: GB2559953A
Application number: GB1700697.4A
Authority: GB
Inventors: Collins Mark
Original assignee: Ihod Ltd
Current assignee: Ihod Ltd
Priority date: 2017-01-14
Filing date: 2017-01-14
Publication date: 2018-08-29
Also published as: GB201700697D0; WO2018130622A1

Abstract

An apparatus for generating hydrogen is disclosed comprising a handheld container; the container having a hollow interior defining a reaction chamber 50, and being provided with a reactant inlet chamber 36 for receiving solid unit dosage forms comprising one or more reactants capable of reacting in the presence of a liquid co-reactant to form hydrogen; wherein the reactant inlet chamber has a first reclosable opening which opens to the container exterior for receiving the solid unit dosage forms; and a second reclosable opening 40 communicating with the reaction chamber through which the solid unit dosage forms can be introduced into the reaction chamber; at least one of the first and second reclosable openings being provided with a gas tight seal to prevent leakage of hydrogen gas from the reaction chamber; the container further having a hydrogen gas outlet 28 and a liquid co-reactant inlet 26, each being provided with valves to enable the control of fluid; whereby in use, the one or more reactants in the solid unit dosage form react in the presence of liquid co-reactant introduced through the liquid co-reactant inlet to generate hydrogen.

Description

(54) Title of the Invention: An apparatus for generating hydrogen Abstract Title: An apparatus for generating hydrogen (57) An apparatus for generating hydrogen is disclosed comprising a handheld container; the container having a hollow interior defining a reaction chamber 50, and being provided with a reactant inlet chamber 36 for receiving solid unit dosage forms comprising one or more reactants capable of reacting in the presence of a liquid co-reactant to form hydrogen; wherein the reactant inlet chamber has a first reclosable opening which opens to the container exterior for receiving the solid unit dosage forms; and a second reclosable opening 40 communicating with the reaction chamber through which the solid unit dosage forms can be introduced into the reaction chamber; at least one of the first and second reclosable openings being provided with a gas tight seal to prevent leakage of hydrogen gas from the reaction chamber; the container further having a hydrogen gas outlet 28 and a liquid coreactant inlet 26, each being provided with valves to enable the control of fluid; whereby in use, the one or more reactants in the solid unit dosage form react in the presence of liquid co-reactant introduced through the liquid co-reactant inlet to generate hydrogen.

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AN APPARATUS FOR GENERATING HYDROGEN

This invention relates to a handheld apparatus for generating hydrogen.

Background of the Invention

In recent years, fuel cells have become increasingly popular as a means of generating electricity in situations where there is no mains power available. Fuel cells typically run on hydrogen and have a number of advantages over internal combustion engines traditionally used in stand-alone power generators. Thus, the waste product of the operation of a fuel cell run on hydrogen is solely water, and no carbon dioxide or carbon monoxide is produced. Fuel cells are also more efficient than internal combustion engines. A further advantage of a fuel cell compared to a conventional petroleum burning generator is that fuel cells can be miniaturised, thereby making them more portable. One example of a portable fuel cell is the proton exchange membrane (PEM) fuel cell. Light weight fuel cells capable of producing a continuous output of 150W and 230V are now commercially available. One such commercially available fuel cell is the Hymera™ fuel cell generator produced by BOC. The Hymera fuel cell generator has a length of 433mm, a width of 188mm, a height of 278mm and a weight of 7kg.

However, a problem with the use of hydrogen-based fuel cells is that they require a supply of hydrogen. In many remote locations and field situations, a supply of hydrogen may simply be unobtainable. Thus, currently, the use of hydrogen-based fuel cells is limited by the difficulties in obtaining or maintaining a supply of hydrogen.

It is known that hydrogen can be generated by the reaction of various metals with acid or alkali. For example, US4325355 describes a heating system in which an exothermic reaction between a solid metal and a solution takes place in a reactor containing a heat exchanger. In the specific reaction system described, aluminium pieces are lowered into a solution of sodium hydroxide solution. During the reaction between aluminium and sodium hydroxide solution, the aluminium is converted to aluminium hydroxide with the evolution of hydrogen gas. The aluminium hydroxide reacts with the sodium hydroxide to form sodium aluminate. The generation of hydrogen by the reaction of aluminium with sodium hydroxide is also described in US2009/0252671 (Fullerton). The hydrogen generating apparatuses of the type described above are relatively large scale fixed installations that are not readily suited to portable use.

At present, there remains a need for an apparatus that is portable, lightweight and can preferably be carried by a person as part of his or her personal luggage (for example in a ruck sack) and which can provide hydrogen on demand in remote or field situations, for example in humanitarian relief operations, where it is not possible or practicable to use hydrogen storage containers such as gas cylinders.

Summary of the Invention

The present invention provides a portable handheld device for generating hydrogen on demand.

In a first aspect, the invention provides an apparatus for generating hydrogen; the apparatus comprising:

a container having dimensions that enable it to be held in a human hand; the container having a hollow interior defining a reaction chamber, and being provided with a reactant inlet chamber for receiving solid unit dosage forms comprising one or more reactants capable of reacting in the presence of a liquid co-reactant to form hydrogen;

wherein the reactant inlet chamber has a first reclosable opening which opens to the container exterior for receiving the solid unit dosage forms; and a second reclosable opening communicating with the reaction chamber through which the solid unit dosage forms can be introduced into the reaction chamber;

at least one of the first and second reclosable openings being provided with a gas tight seal to prevent leakage of hydrogen gas from the reaction chamber;

the container further having a hydrogen gas outlet and a liquid co-reactant inlet, each being provided with valves to enable the control of fluid therethrough;

whereby in use, the one or more reactants in the solid unit dosage form react in the presence of liquid co-reactant introduced through the liquid co-reactant inlet to generate hydrogen.

The container has dimensions that enable it to be held in a human hand. Thus the container can typically be grasped or lifted and carried using a single human hand. The “handheld” apparatus of the invention can comprise a container having a minimum dimension of up to about 7cm so that it can be held in a hand. For example, the container can have a width (e.g. diameter where the container is of circular cross section) of up to about 7cm. More usually, the container will have a minimum dimension (e.g. width/diameter) of up to about 6.5cm, for example from 5.5-6.5cm. In one embodiment, the container has a minimum dimension (e.g. width/diameter) of about 5.8-6.2cm.

The apparatus of the invention may be connected to a device (e.g. a portable or handheld device) that consumes hydrogen. For example, the apparatus may be connected to a fuel cell. The fuel cell is typically a portable fuel cell such as a proton exchange membrane (PEM) fuel cell. An example of a portable fuel cell is the Hymera ™ fuel cell described above.

Thus, in a further aspect, the invention provides an apparatus as defined herein in combination with a fuel cell, e.g. a PEM fuel cell.

The apparatus and fuel cell combinations are of particular use in situations where there is no direct access to electricity. They may be used, for example, in field situations to charge devices such as computers, mobile phones and other portable electronic devices such as military communication units or for the continuous cooling of essential medical items within a small fridge.

The apparatus of the invention makes use of solid unit dosage forms containing one or more reactants that react in the presence of a liquid co-reactant to generate hydrogen. The solid dosage forms can take the form of tablets, the term tablets as used herein referring to a unitary dosage form typically formed by moulding and/or compression although it may also be formed by casting and by division of a larger dosage form. As an alternative to tablets, the solid dosage form can take the form of a capsule containing one or more reactants in solid, semi-solid or gel form. The solid unit dosage forms are typically constructed to provide an (at least approximately) known amount of hydrogen after reaction in the presence of the liquid co-reactant.

The solid unit dosage forms may contain a single reactant or more than one reactant. In one embodiment, the solid unit dosage form contains only a single reactant that reacts directly with the liquid co-reactant to form hydrogen. In another embodiment, the unit dosage form contains a first reactant that reacts with one or more further reactants in the presence of the liquid co-reactant to form hydrogen.

In one particular embodiment, the solid unit dosage form contains two or more reactants that react together in the presence of a liquid co-reactant to generate hydrogen. In another embodiment, a plurality (e.g. two or three, more usually two) different unit dosage forms are provided, each comprising a different reactant or combination of reactants.

Preferably, the reactants necessary for the generation of hydrogen in the presence of the liquid co-reactant are present in a single unit dosage form.

Where a unit dosage form contains more than one reactant, a barrier may be provided so as to separate the reactants. For example, in a tablet, two or more reactants may be presented as different layers of a tablet. In order to prevent premature reaction in the dry state between the reactants, a barrier film (e.g. a polymeric barrier film) may be interposed between at least two of the reactants.

The barrier film may comprise a soluble or dispersible polymer which dissolves or disperses to release the reactants when contacted with the liquid co-reactant. In an alternative form, the tablet may comprise particles (e.g. beads or pellets or granules) of one or more reactants wherein the particles of at least one reactant are coated with a protective coating that breaks down or dissolves once the unit dosage form comes into contact with the liquid co-reactant. Similarly, in a capsule formulation, particles (e.g. beads or pellets or granules) of at least one reactant may be provided with a protective coating such as a polymeric coating.

The dry dosage forms (e.g. unit dosage forms) may be provided with a protective wrapping or outer container that the user removes or opens to give access to the dosage form prior to use. The protective wrapping or outer container is typically constructed to protect the dry dosage form from attack by moisture.

Where the reaction between a reactant and liquid co-reactant, or two or more reactants in the presence of liquid co-reactant, is particularly vigorous, controlled release technology may be used to control the rate of release of one or more reactants so as to slow down the hydrogen-generating reaction and prevent excessive heat generation. For example, one or more reactants may be coated in a slowly dissolving or eroding polymer that releases reactants at a controlled rate.

Protective coatings and release-controlling coatings and polymers are well known in the art, particularly in the pharmaceutical sciences, and need not be discussed in detail here.

The liquid co-reactant is typically water or a liquid medium containing water. The water may be the sole reactive component of the liquid co-reactant or the liquid co5 reactant may contain other reactive substances. In one embodiment, water is the sole reactive component in the liquid co-reactant.

The reactants can be any substances that react with the liquid co-reactant (e.g. water) or with other reactants in the presence of the liquid co-reactant (e.g. water) to generate hydrogen.

For example, the reactants can take the form of a metal (e.g. a finely divided metal) that reacts with the liquid co-reactant (e.g. water) to form hydrogen.

In another embodiment, the reactants can take the form of a metal (e.g. a finely divided metal such as a metal powder) and an acid or an alkali that reacts with the metal to generate hydrogen. Where the reactant comprises an acid or an alkali, the acid or alkali will be in solid form or will be contained within a solid dosage form.

The metal can be, for example, an alkali metal or alkaline earth metal, a group III metal such as aluminium, a non-transition metal such as zinc, or a transition metal.

Examples of acids include solid acids such as citric acid and tartaric acid, or mineral acids such as sulphuric acid and hydrochloric acid contained in a protective matrix (see for example W02009/022123 (Concentrated Solutions Limited).

Examples of alkalis include sodium and potassium hydroxide.

In one particular embodiment, the reactants comprise a metal powder such as zinc or aluminium and an alkali metal hydroxide.

A particular pair of reactants that may be used to generate hydrogen comprises finely divided aluminium and sodium hydroxide.

The container has a reactant inlet chamber for receiving the solid unit dosage forms. The reactant inlet chamber has a first reclosable opening which opens to the container exterior for receiving the solid unit dosage forms and a second reclosable opening communicating with the reaction chamber through which the solid unit dosage forms can be introduced into the reaction chamber.

At least one of the first and second reclosable openings is provided with a gas-tight seal to prevent leakage of hydrogen gas from the reaction chamber. In one embodiment, both the first and second reclosable openings are provided with gastight seals and hence the reactant inlet chamber functions as an air-lock between the reaction chamber and the container exterior.

The first reclosable opening can be closed by a closure device that can be opened to receive the solid unit dosage form and then closed to bring the solid unit dosage form into the inlet chamber. The closure device can be, for example, a lid or a drawer. In one embodiment, the closure is a drawer set into a side wall of the container.

The drawer may be configured so that it can hold a solid dosage form such as a tablet but is unable to hold materials in liquid or powder form. Thus, for example, the draw may have one or more bottom openings through which any liquid or powdered materials would fall before they could enter the reactant inlet chamber.

The first reclosable closable opening may be provided with sealing means for providing a gas-tight seal between the inlet chamber and the container exterior.

For example, where the closure device is a lid or drawer, the sealing means may comprise a sealing gasket around the opening and/or a sealing gasket on the lid or drawer.

The second reclosable opening provides communication with the reaction chamber and enables the solid unit dosage forms to be introduced into the reaction chamber. The second reclosable opening can be closed by means of a valve or door which can be opened to permit the solid unit dosage form to pass (e g. fall) into the reaction chamber. The valve or door, when closed, preferably forms a gas tight seal that prevents hydrogen from escaping from the reaction chamber into the reactant inlet chamber.

The reactants are introduced into the reaction chamber in the form of solids. In the presence of liquid co-reactant (e.g. water) introduced into the reaction chamber through the liquid co-reactant inlet (e.g.water inlet), the reactants react to form hydrogen. The hydrogen then passes out through the hydrogen gas outlet and on to a coupled device such as a PEM fuel cell that consumes hydrogen.

Both the water inlet and the hydrogen gas outlet are controlled by valves. Thus, for example, the hydrogen gas outlet can be provided with a one way valve allowing the escape of hydrogen but not allowing gases or other fluids to enter the reaction chamber. Alternatively, the hydrogen gas outlet can be provided with an on-off valve or a two way valve that can be closed to prevent escape of hydrogen. In this latter case, means may be provided for venting hydrogen to the atmosphere if the gas pressure within the reaction chamber exceeds a predetermined limit.

The liquid co-reactant inlet (e.g. water inlet) may likewise be provided with a one way valve, which allows liquid co-reactant (e.g. water) to be introduced into the reaction chamber but does not allow gas or other material to escape from the reaction chamber.

The apparatus of the invention is a handheld apparatus. During the hydrogen generation reaction, the container may become very hot. It may therefore be provided with a layer of thermal insulation so that it can be held in the hand without burning the hand of the user. The layer of thermal insulation may take the form of a jacket or sleeve of a thermally insulating material disposed around an outer side wall of the container. The jacket or sleeve may, for example, be formed from a cellulose-based material such as paper or card or may be formed from an insulating polymer. Examples of insulating polymers include polymer foams such as polyurethane foams and polymers such as heat resistant silicone polymers.

In an alternative embodiment, the apparatus may be provided with a liquid cooling jacket around the container, for example a jacket or outer container containing cooling water.

In one embodiment, the apparatus comprises an outer container and, contained therein, an inner container;

the inner container having a hollow interior which defines the reaction chamber;

a void for holding cooling water being present between an inner wall of the outer container and an outer wall of the inner container, a cooling water inlet being provided for introducing water into the void;

wherein the reactant inlet chamber extends from within the inner container through the outer container so that the first reclosable opening is accessible from the exterior of the outer container; and wherein the hydrogen gas outlet and liquid co-reactant inlet ((e.g.water inlet) for the reaction chamber extend from the reaction chamber through the outer container and are accessible from the exterior of the outer container.

The cooling water can be clean cooling water or impure or dirty water.

An inlet is provided for admitting cooling water into the void between the said inner and outer walls. The inlet can take the form of, for example, a reclosable opening in a wall of the outer container or a removable portion of the outer wall. When the inlet takes the form of a removable portion of the outer wall, it may, for example, comprise a removable cap.

Heat generated in the reaction chamber will heat the water in the void between the inner and outer container walls causing it to evaporate. The water vapour produced in this way can be collected by a suitable condensing means typically located at an upper end of the outer container.

Accordingly, in one preferred embodiment, the invention provides an apparatus comprising inner and outer containers as defined herein, wherein the outer container is provided with condensate collection means for condensing and collecting evaporated cooling water. The condensate collection means is preferably connected to a clean water outlet mounted in an outer wall of the outer container.

Thus, an ancillary use of an apparatus of the invention having inner and outer containers is to provide a means of purifying dirty water. Water introduced into the void and caused to evaporate by the heat produced in the reaction chamber is condensed and collected as clean water.

The collection means for condensing and collecting evaporated cooling water can take the form of a sloping condensation surface at an upper end of the outer container, the sloping condensation surface sloping downwardly to a collection point linked to the clean water outlet. Thus, for example, where the outer container is cylindrical, the sloping condensation surface can be an inverted conical surface, with a collection point at the tip of the inverted cone.

The collection means can be at least partially housed within a removable cap, the removal of which enables cooling water to be introduced into the void.

A benefit of the apparatus of the invention is that it does not require a source of clean water in order to function. Any available source of water, clean or dirty can be used for both the aqueous medium in the reaction chamber and any cooling water used in the water cooled version of the apparatus. A further benefit of the apparatus is that, when the apparatus has outer and inner containers with a void for cooling water, the apparatus can be employed to purify dirty water by the simple expedient of allowing the cooling water to be evaporated by the heat from the reaction chamber and then condensing and collecting the evaporated water.

The container (or the inner and outer container when present) can be made from a variety of materials and in particular metals (such as stainless steel) and plastics materials. The container (or inner container) can comprise a stainless steel cylindrical main body portion and separately formed base and cap portions that may also be made from stainless steel or can be made from a plastics material.

The base may be configured so as to be removable to give access to the interior of the reaction chamber for cleaning and inspection purposes. For example, the base and main body portion may be secured together by means of a screw thread. Similarly, the cap and main body portion may be secured together by means of a screw thread. In each case, sealing elements such as sealing rings or gaskets may be used to ensure that the connection between the base and main body portion, or between main body portion and cap, is gas-tight. The materials from which the container (or inner container) are made will be resistant to the chemical reactants and reaction products inside the reaction chamber. Where the materials are insufficiently chemically resistant in their own right, the inner walls (i.e. the walls defining the reaction chamber) may be coated with an inert substance as PTFE. The PTFE may be applied, for example, by means of vapour deposition in accordance with known methods.

The invention will now be illustrated in more detail (but not limited) by reference to the specific embodiment shown in the accompanying drawings.

Brief Description of the Drawings

Figure 1 is a perspective view of an apparatus according to a first embodiment of the invention.

Figure 2 is a view from one side of the apparatus of Figure 1.

Figure 3 is a side view of the apparatus of Figure 2 rotated through 90°.

Figure 4 is a view from above of the apparatus of Figures 1 to 3.

Figure 5 is a side sectional view through the apparatus of Figures 1 to 4

Figure 6 is an enlarged view of part of Figure 5.

Figure 7 is an enlarged view corresponding to Figure 6 but rotated through 90°.

Detailed Description of the Invention

Figure 1 is a perspective view of an apparatus according to a first embodiment of the invention. The apparatus comprises an outer container 2 and, contained therein, an inner container 4. The outer container 2 comprises a cylindrical main body portion 6, a base 8 and a cap 10. In this embodiment, the main body portion 6 is formed from stainless steel, although it may alternatively be formed from a gas-impermeable plastics material which is resistant to the reactants and reaction products used and formed in the apparatus. The base 8 may also be formed from stainless steel or a suitable plastics material and, in this embodiment, is removably secured to the main body portion by means of a screw thread. A PTFE gasket (not shown) provides a gas-tight seal between the base 8 and main body portion 6. The cap 10 is likewise formed from a stainless steel or plastics material and is removably attached to the main body portion 6.

Located inside the outer container 2 is an inner container 4 which comprises a main body portion 12, a base 14 and a cap 16. The main body portion 12, base 14 and cap 16 together form a hollow container, the interior of which serves as a reaction chamber 50. The inner surfaces of the main body portion 12, base 14 and cap 16 may advantageously be coated with a fluoropolymer such as PTFE to increase resistance to attack by the reactants and reaction products.

Set into the cap 16 of the inner container 4 are a valved internal water inlet 18 and a valved internal gas outlet 20 which communicate via short lengths of tubing 22, 24 with corresponding external water inlet port 26 and external gas outlet port 28 mounted in the cap 10 of the outer container.

The main body portion 12 of the inner container and the main body portion 6 of the outer container 2 are provided with aligned inner and outer openings 30 and 32 respectively in which in which is mounted a sliding drawer 34. The innermost end of the drawer 34 is slidably mounted within a reactant inlet chamber 36 defined by a roof 38, a sliding floor panel 40, side walls 42 and an end wall 44 mounted within the body of the inner container 2. The drawer 34 is provided with sealing elements (not shown) so that when it is in a closed position, a fluid-tight seal is formed between the drawer 34 and the surrounding walls of the inner opening 30. The inner opening 30 thus constitutes a first reclosable opening for the reactant inlet chamber.

A drawer release button 46 is mounted in the wall of the outer container 2 beneath the drawer opening 32 and is linked by an actuating bar or rod 48 to a spring loaded drawer-retaining latch (not shown). The drawer-retaining latch holds the drawer in the reactant inlet chamber against the force of a spring or other resilient element (not shown) located between the end wall 44 and the inner end of the drawer 34. Depressing the button 46 releases the latch thereby enabling the drawer 34 to move out of the reactant inlet chamber under the force of the resilient element and into an open position. When the drawer 34 is pushed back into the reactant inlet chamber to its closed position, the spring loaded drawer-retaining latch re-engages the drawer 34 to hold it in place. The resilient element is preferably damped to prevent the drawer 34 from being ejected from the reactant inlet chamber too quickly.

The sliding floor panel 40 of the reactant inlet chamber 36 can be opened to allow communication between the reactant inlet chamber and the reaction chamber 50. The sliding floor panel 40 is provided with sealing elements (not shown) that form a fluid tight seal around the edges of the panel when the panel is in a closed position to prevent fluids from passing into or out of the reaction chamber 50. Thus, the sliding floor panel constitutes a second reclosable opening for the reactant inlet chamber.

The drawer 34 has a lower wall or floor on which a tablet or other solid dosage form containing reactants may be placed when the drawer 34 is pushed back into the reactant inlet chamber. The lower wall of the drawer has an opening (not shown) large enough to enable the tablet or other dosage form to pass through.

By virtue of the gas-tight seals preventing escape of gas through the first and second reclosable openings when they are in the closed position, the reactant inlet chamber 36 can function as an airlock. When the drawer is in its open position, the second reclosable opening in the floor of the reactant inlet chamber can remain sealed. Once the drawer is pushed back into the reactant inlet chamber and the first reclosable opening is thus resealed, the second reclosable opening may then be opened by releasing the sliding floor panel 40 to allow the reactant tablet to fall into the reaction chamber 50.

In the reaction chamber 50, hydrogen can be generated through the chemical reaction of two or more chemical reactants. The reactants are introduced in dry unit dose form through the reactant inlet chamber 36 as described above. Water (or an aqueous medium) is then introduced into the reaction chamber 50 through the water inlet 26, 22, 18. The water can be clean water or, in the absence of clean water, dirty water (e.g. river water) can be used. The water dissolves or causes the disintegration of the reactant tablet so that either a reactant reacts with water to generate hydrogen gas, or two or more reactants react with each other to generate hydrogen gas.

Hydrogen gas generated by the chemical reaction is vented from the container through the gas outlet 20, 24, 28 which, in use, is typically connected to a device such as a fuel cell that uses hydrogen as a fuel. The fuel cell is typically a portable fuel cell such as a proton exchange membrane (PEM) fuel cell.

The quantity of reactant in the unit dosage form is sufficient to provide hydrogen pressures within the reaction chamber 50 of 2-3 bar, which is of the order of magnitude required for a PEM fuel cell. A pressure gauge (not shown) may be provided to enable the user to determine whether a fresh charge of reactant is required.

The chemical reactants are provided in dry unit dose form and the dry unit doses are constructed so that the reactants do not react to generate hydrogen until they come into contact with water. The dry unit doses can contain a single reactant that reacts with water to generate hydrogen or they can contain two or more reactants that react together in water, or with water, to generate hydrogen.

Where the unit doses contain two reactants, the individual reactants can be presented in separate unit doses or as part of a single integrated unit dose. Where there are more than two reactants, each reactant can be presented in a separate unit dose or two or more of the reactants may be presented in a single integrated dosage form.

The unit doses can take the form of a tablet. In order to prevent premature reaction between the reactants, the reactants can be separated by a barrier material, for example, a water soluble polymeric material. In one embodiment, reactants that might otherwise react in the dry state are separated into layers, with a layer of a barrier material such as a water soluble or water dispersible polymer being interposed between the layers. For example, in one particular embodiment, a tablet may comprise two layers separated by a barrier film of a water-soluble or waterdispersible material, one layer containing a first reactant and the other layer containing a second reactant. In another embodiment, the tablet may comprise a compressed mixture of the reactants in which one or more of the reactants is present in the form of pellets or granules coated with a water-soluble or water dispersible protective coating, for example a water-soluble or water-dispersible polymer.

The reactants may be any one or more chemical entities that react together to form hydrogen. In one embodiment, the reactants are aluminium powder or aluminium pellets or microbeads and an alkali metal hydroxide such as sodium hydroxide.

The reaction used to generate hydrogen is typically an exothermic reaction and high temperatures (e.g. up to about 130°C) are generally produced within the reaction chamber. The container may therefore be insulated to prevent burns to the user during operation. Alternatively, a cooling system may be employed to carry away the heat generated inside the reactor. In one embodiment, the apparatus may comprise an outer container containing a coolant liquid and an inner container within which the reaction takes place.

In the apparatus illustrated in the drawings 1 to 7, a cooling liquid is used to remove heat generated in the reaction chamber 50. The cooling water is held in a void 52 between the outer wall of the inner container 4 and the inner wall of the outer container 2. The cooling water can be introduced into the void through an inlet port (not shown) or it can be introduced into the outer container by removing the cap 10 of the outer container 2. To enable the cap to be removed and replaced, it may be provided with a screw thread (not shown) that engages a mating screw thread (not shown) on the inner surface of the main body portion 6 of the outer container. Where the cap is removable, sealing means such as a sealing gasket (not shown) are provided to give a fluid tight seal between the cap and container body.

The cap is provided on its inner side with a downwardly oriented conical condenser surface 54 which is formed from a thermally conductive material such as stainless steel. Immediately below the apex of the conical surface is an open-topped collector vessel 56 which is connected via tubing 58 to a clean water outlet 60.

In use, heat generated by the exothermic chemical inside the reaction vessel 50 heats up the water in the void 52, causing it to evaporate. The water vapour condenses on the conical condenser surface 54 and is collected and channelled to the clean water outlet 60. Although a source of clean water may be used to provide the cooling water where such clean water is plentiful, the apparatus of the invention will more usually be used in circumstances where no clean water is available. In such cases, dirty water (e.g. water for a well or river, or other sources such as urine) can be used as the cooling water. The apparatus of the invention can thus be used as a means of purifying water by distillation as well as providing a source of hydrogen.

The embodiments described above and illustrated in the accompanying figures and tables are merely illustrative of the invention and are not intended to have any limiting effect. It will readily be apparent that numerous modifications and alterations may be made to the specific embodiments shown without departing from the principles underlying the invention. All such modifications and alterations, are intended to be embraced by this application.

Claims

1. An apparatus for generating hydrogen; the apparatus comprising:

a container having dimensions that enable it to be held in a human hand;

the container having a hollow interior defining a reaction chamber, and being provided with a reactant inlet chamber for receiving solid unit dosage forms comprising one or more reactants capable of reacting in the presence of a liquid co-reactant (e.g. water) to form hydrogen;

the container further having a hydrogen gas outlet and a liquid coreactant inlet (e.g. water inlet), each being provided with valves to enable the control of fluid therethrough;

whereby in use, the one or more reactants in the solid unit dosage form react in the presence of the liquid co-reactant (e.g. water) introduced through the liquid co-reactant inlet (e.g. water inlet) to generate hydrogen.

2. An apparatus according to claim 1 wherein both the first and second reclosable openings are provided with gas-tight seals and hence the reactant inlet chamber functions as an air-lock between the reaction chamber and the container exterior.

3. An apparatus according to claim 2 wherein the first reclosable opening is closed by a closure device that can be opened to receive the solid unit dosage form and then closed to bring the solid unit dosage form into the inlet chamber.

4. An apparatus according to claim 3 wherein the closure device is a drawer.

5. An apparatus according to any one of the preceding claims, the apparatus comprising an outer container and, contained therein, an inner container; the inner container having a hollow interior which defines the reaction chamber;

5 a void for holding cooling water being present between an inner wall of the outer container and an outer wall of the inner container, a cooling water inlet being provided for introducing water into the void;

wherein the reactant inlet chamber extends from within the inner container through the outer container so that the first reclosable opening is accessible

10 from the exterior of the outer container; and wherein the hydrogen gas outlet and liquid co-reactant inlet (e.g. water inlet) for the reaction chamber extend from the reaction chamber through the outer container and are accessible from the exterior of the outer container.

6. An apparatus according to claim 5 wherein the outer container is provided

15 with condensate collection means for condensing and collecting evaporated cooling water, the condensate collection means being connected to a clean water outlet mounted in an outer wall of the outer container.

7. An apparatus according to claim 6 wherein the collection means for condensing and collecting evaporated cooling water takes the form of a

20 sloping condensation surface at an upper end of the outer container, the sloping condensation surface sloping downwardly to a collection point linked to the clean water outlet.

8. A method of generating hydrogen using the apparatus of any one of claims 1 to 7, which method comprises introducing into the reaction chamber one

25 or more reactants in a solid unit dosage form and then introducing a liquid co-reactant (e.g.) water into the reaction chamber to bring about chemical reaction and the generation of hydrogen.

9. A method according to claim 8 wherein the chemical reaction is exothermic and heat generated by the reaction is used for the purification of water by

30 distillation.

Intellectual

Property

Office

Application No: GB1700697.4