WO2023227872A1

WO2023227872A1 - An electrolysis apparatus and a burner

Info

Publication number: WO2023227872A1
Application number: PCT/GB2023/051341
Authority: WO
Inventors: Thomas W K LAM
Original assignee: Lam Thomas W K
Priority date: 2022-05-27
Filing date: 2023-05-23
Publication date: 2023-11-30
Also published as: GB202207851D0; GB2619087A

Abstract

An Electrolysis Apparatus and a Burner An electrolysis apparatus (200) for generating oxygen and hydrogen, comprising: a storage tank (210) for storing a volume of water; at least one electrolysis cell (100a-d) for electrolysing water fed from the storage tank (100) to generate oxygen and hydrogen respectively at an anode (120) and a cathode (130), the generated oxygen and hydrogen are separated by a proton exchange membrane (110) and are arranged to discharge through respective oxygen and hydrogen discharge pipes (124, 134), and wherein during use at least a portion of water in the electrolysis cell (100a-d) is arranged to recycle back to the storage tank (210) by the oxygen discharge pipe (124); and a heat exchanger (220a) arranged externally to the electrolysis cell (100a-d), the heat exchanger (220a) is configured to cool the recycled water.

Description

An Electrolysis Apparatus and a Burner

Field

The present invention relates to an electrolysis apparatus and a burner, and in particular to a burner using oxygen and hydrogen generated by an electrolysis apparatus.

Background

It is known to use hydrogen and oxygen in a burner such as in a welding torch. The oxygen and hydrogen are normally supplied in the form of compressed gas in a cylinder. The hydrogen and oxygen are pre-mixed in a chamber and then the mixed gas is fed to a burner jet where the gases are ignited.

One problem with hydrogen and oxygen is that the combination is highly explosive and a blowback (commonly referred to as flashback or popping) can occur where the flame ignites the hydrogen and oxygen in the chamber leading to explosions. Safety valves are often used to prevent the further supply of hydrogen and oxygen when this occurs which adds to the cost, along with the additional cost for the control systems which operate the valves. Furthermore, a lowered pressure in an emptying hydrogen gas cylinder may lead to a flashback at the torch tip. Therefore, such a hazard inhibits the widespread use of hydrogen and oxygen in many applications, such as cooking stoves and central heating boilers.

In addition to their bulk sizes, another drawback of using gas cylinders is that they can take some time to procure. Therefore, the use of electrolysers as an alternative gas source has received significant interest in recent years. By employing a Proton Exchange Membrane (PEM) in an electrolysing cell, electrolysers generate hydrogen and oxygen gases in separate streams at the correct stoichiometry ratio, requiring only water and an electrical source. Thus, not only they are more portable than conventional gas cylinders, but their use may also ensure a steady supply of hydrogen and oxygen gases over a prolonged period.

However, electrolysis is an energy-intensive process, and it is estimated that around 30-40% of supplied electrical energy is converted into heat. Whilst some of the heat produced during electrolysis is utilised to maintain the required operating temperate, commercially available electrolysers often demand significant cooling within the electrolysing cell to dissipate excess heat, e.g. by means of refrigeration or thermoelectric cooling. This increases the size and complexity of the electrolysis cell, as well as negatively impacting the overall efficiency of the electrolyser.

Therefore, a burner that reduces or eliminates the risk of flashback, and an electrolyser apparatus that is compact and efficient, are highly desirable.

Summary

According to a first aspect of the present invention, there is provided an electrolysis apparatus for generating oxygen and hydrogen, comprising: a storage tank for storing a volume of water; at least one electrolysis cell for electrolysing water fed from the storage tank to generate oxygen and hydrogen respectively at an anode and a cathode, the generated oxygen and hydrogen are separated by a proton exchange membrane and are arranged to discharge through respective oxygen and hydrogen discharge pipes, and wherein during use at least a portion of water in the electrolysis cell is arranged to recycle back to the storage tank by the oxygen discharge pipe; and a heat exchanger arranged externally to the electrolysis cell, the heat exchanger is configured to cool the recycled water.

The electrolysis cell may be an electrochemical device for converting electricity and water into hydrogen and oxygen, and it may be an electrolysis cell of any known design. In its simplest form, the electrolysis cell may contain the proton exchange membrane (PEM) which sealingly divides the electrolysis cell into two sections each containing one of the anode and the cathode. The electrodes typically comprise catalysts such as platinum or iridium and may be energised by a suitable electric power supply.

During electrolysis, water fed from the storage tank is oxidised at the anode to generate oxygen gas, protons and electrons. The protons may conduct through the PEM to the cathode, thereby combining with the supplied electron to form hydrogen gas thereat. Thus, the generated oxygen and hydrogen gases may be separately discharged through respective oxygen and hydrogen discharge pipes.

In contrast to known electrolysers, the electrolysis cell may be provided in absence of any cooling means. That is, some or all of the water inside the electrolysis cell, at a temperature above ambient temperature (e.g. at a desired operating temperature of the electrolysis cell), may be continuously discharged and recycled to the storage tank through the oxygen discharge pipe. A heat exchanger may be provided externally to the electrolysis cell for cooling the said recycled water, which in turn may mix with the stored water in the storage tank. The recycled water may be cooled to a temperature lower than the temperature at the electrolysis cell. In some embodiments, the recycled water may be cooled to, or below, the ambient temperature. In some cases, the cooled recycled water may advantageously reduce the temperature of the water that is subsequently fed to the electrolysis cell. As a result, the temperature inside the electrolysis cell may be readily regulated by controlling the temperature and/or the quantity of recycled water.

In some embodiments, the heat exchanger cools the recycled water in the oxygen discharge tube, e.g. the oxygen discharge tube may be connected in line with the heat exchanger. Alternatively, or in addition, the heat exchanger may be provided to directly cool the water (e.g. both the recycled water and stored water) inside the storage tank. The heat exchanger may be any suitable cooler, for example, a water-air heat exchanger, an evaporative cooler or a vapour-compression refrigerator.

By removing the cooling means from within the electrolysis cell, such an arrangement may advantageously reduce the complexity and the size of the electrolysis cell. Furthermore, the heat exchanger may be serviced independently of the electrolysis cell. Moreover, in an apparatus with a plurality of electrolysis cells, the temperature in each of the cells may be centrally regulated through collective cooling of recycled water discharged from all the plurality of cells. Additionally, the cooling of the oxygen and water mixture helps to condense water vapour in the oxygen gas, thus reducing and/or eliminating the need for gas drying prior to consumption.

In some embodiments, the hydrogen discharged from the electrolysis cell may bypass the storage tank. For example, since the hydrogen discharge pipe may be in absence of water, it may directly connect to a gas drier for reducing the humidity of the hydrogen gas, or it may be connected to a hydrogen outlet for immediate consumption. This arrangement may be particularly applicable to electrolysis cells where water is not provided in the section containing the cathode.

Alternatively, the storage tank comprises a first compartment and a second compartment each having a fluid inlet fluidly connected to respective oxygen and hydrogen discharge pipes, each of the first and second compartments is configured to receive the respective oxygen and hydrogen in their headspaces. More specifically, in these embodiments, both the oxygen and hydrogen gases may discharge into their respective first and second compartments at the storage tank, as such the headspaces in the first and second compartments may serve as buffering space for the gases, thereby mitigating fluctuations in gas supply/consumption. In some embodiment, accumulated water in the cathode section of the electrolysis cell may be discharged to the second compartment in the storage tank, alone with the discharged hydrogen, by the hydrogen discharge tube.

Optionally, the fluid inlets of the first and second compartments are arranged to submerge in the water stored in the storage tank, and wherein during use the oxygen and hydrogen gases rise through the stored water to their respective headspaces. The fluid inlets may be provided with a suitable one-way valve to prevent the backflow of water from the storage tank to the electrolysis cell. Advantageously, the stored water in the storage tank may be agitated by the bubbling gas, thus improving convection and the associated heat transfer therein.

Alternatively, the fluid inlets of the first and second compartments are arranged at a level above the stored water in the storage tank. In these embodiments, the oxygen gas and water are separated by gravity upon entering through the fluid inlet.

Optionally, the oxygen and hydrogen in their respective first and second compartments are sealed from each other. For example, the first and second compartments may be separated by a wall extending across the storage tank. Alternatively, the first and second compartments may be provided with a fluid passage that allows water to flow therebetween, where a water trap may be installed in the fluid passage to prevent the oxygen and hydrogen in their respective compartments to come into contact. This may advantageously promote convective heat transfer between the first and second compartments.

Optionally, the first and second compartments each comprises a gas outlet fluidly communicable with a respective gas drier for reducing the humidity of the oxygen and hydrogen gases. Each drier may be fluidly connected to a respective gas supply outlet for outputting the oxygen and hydrogen from the electrolysis apparatus. The gas drier may be any suitable gas drier such as filters, membrane driers and desiccant driers such as silica gel. Advantageously, such an arrangement may improve the potency of the generated gas, thereby eliminating the occurrence of so-called "wet flame".

Preferably, the at least one electrolysis cell comprises a plurality of electrolysis cells in a parallel arrangement. For example, the water fed from the storage tank may be distributed, optionally with individual flow control, to each of the plurality of electrolysis cells. The oxygen and water from each of the electrolysis cells may be collectively discharged to the storage tank by a single oxygen discharge pipe. Likewise, the hydrogen from each of the electrolysis cells may be collectively discharged to the storage tank, or the drier, by a single hydrogen discharge pipe.

Optionally, the electrolysis apparatus may be mains- or battery-powered or powered by green energy such as a solar panel/s or wind generator/s or combinations of these.

According to a second aspect of the present invention, there is provided a hydrogen and oxygen burner comprising: one or more chambers each having an oxygen inlet and at least one oxygen exhaust aperture; and a hydrogen feed pipe for each oxygen exhaust aperture, each feed pipe passing through the or each chamber and having an outlet end passing through an oxygen or hydrogen exhaust aperture, the area of the outlet end through which hydrogen passes having a cross-sectional diameter equal to, or less than, 0.25mm; wherein in use the oxygen and hydrogen being ignitable to create a flame extending from each oxygen exhaust aperture and hydrogen feed pipe outlet end.

Optionally, the area of the feed pipe outlet through which hydrogen passes is substantially twice the area of the exhaust aperture through which oxygen passes. Advantageously, such an arrangement may ensure the hydrogen and oxygen gases are supplied at the correct 2: 1 stoichiometric ratio. Optionally, the feed pipe outlet end extends proud of the oxygen exhaust aperture. Advantageously, such an arrangement may reduce the likelihood of hydrogen gas ingress into the oxygen exhaust aperture, thereby minimising the risk of flashback.

Optionally, the hydrogen feed pipe outlet end and oxygen exhaust aperture is circular.

Optionally, the feed pipe outlet is concentric with the oxygen exhaust aperture.

Optionally, the or each chamber having a single exhaust aperture and a single feed pipe outlet. Optionally, the burner comprises a single chamber having a single exhaust aperture and a single feed pipe outlet. For example, the burner may be a welding or brazing torch.

Alternatively, the chamber comprises a plurality of exhaust apertures and a feed pipe outlet for each exhaust aperture.

Optionally, the chamber comprises first and second opposing end walls spaced by side wall/s with said exhaust apertures in said first end wall, and said feed pipes extend from a second end wall and/or the side wall/s through the chamber and through the exhaust apertures in the first side wall, and optionally the second end wall and/or the side wall/s also forms part of a housing supplying hydrogen to the feed pipes and from which the feed pipes extend.

Optionally, the burner comprises a plurality of chambers distributed around an axis, wherein the one or more outlet ends of each chamber are arranged in a different axial orientation to the outlet ends of at least another chamber. Optionally, the burner comprises a plurality of chambers distributed around an axis, wherein the one or more outlet ends of each chamber are arranged in a different axial orientation to the outlet ends of the other chambers. The plurality of chambers may be arranged equidistant from the axis. The plurality of chambers may be evenly distributed around the axis. More specifically, each chamber may consider to be a discrete heating unit where all of the associated hydrogen feed pipe outlet ends are in the same axial orientation, e.g. facing the same direction with respect to the axis.

Optionally, the one or more outlet ends of each chamber are directed away from, or directed towards, the axis. Optionally, the one or more outlet ends of each chamber are directed at a non-zero angle away from or towards the axis. Optionally, the one or more outlet ends of each chamber are directed away from, or directed towards, other outlet ends of another chamber.

Alternatively, the chamber has first and second opposing end walls spaced by side wall/s with said exhaust apertures in one or more side wall/s, and said feed pipes extend through the exhaust apertures in the side wall/s. The feed pipes may extend from a housing in the chamber supplying hydrogen to the feed pipes and from which the feed pipes extend.

Optionally, the outlet ends extend in the same plane and are angled to each other in the said plane.

According to a third aspect of the present invention, there is provided a central heating boiler comprising the burner of the second aspect.

Optionally, the central heating boiler comprises a radial heat exchanger concentrically extending with one or more chambers along an axis.

According to a fourth aspect of the present invention, there is provided a burner system, comprising the burner of the second aspect and the electrolysis apparatus of the first aspect, wherein during use, the burner consumes the oxygen and hydrogen generated by the electrolysis apparatus to create a flame extending from each oxygen exhaust aperture and hydrogen feed pipe outlet end. According to a fifth aspect of the present invention, there is provided a boiler system, comprising the boiler of third aspect and the electrolysis apparatus of the first aspect, wherein during use the boiler consumes the oxygen and hydrogen generated by the electrolysis apparatus to create a flame extending from each oxygen exhaust aperture and hydrogen feed pipe outlet end.

Features from any one of the first to the fifth aspects of the present invention may be applicable with any other feature from the other aspects.

Brief Description of the Drawings

Embodiments of the invention will now be described with reference to the accompanying drawings in which :

Figure la shows a cross section view of a burner in the form of a welding/brazing torch according to a first embodiment of the present invention;

Figures lb and lc respectively shows a plan view and an enlarged perspective view of a burner in the form of a welding/brazing torch according to a second embodiment of the present invention;

Figure 2A shows a part-exploded perspective view of a burner in the form of a boiler burner according to a third embodiment of the present invention;

Figure 2B shows an assembled perspective view of a burner of Figure 2A;

Figure 2C shows a perspective view of a burner in the form of a boiler burner according to a fourth embodiment of the present invention;

Figure 3A shows a part exploded, part cross section, part perspective view of a burner in the form of a cooker burner according to a fifth embodiment of the present invention; Figure 3B shows an assembled part cross section, part perspective view of Figure 3A;

Figure 4A shows an exploded perspective view of a burner in the form of an alternative cooker I boiler burner according to a sixth embodiment of the present invention;

Figure 4B shows a part exploded, part cross section, part perspective view of the burner of Figure 4A;

Figure 4C shows a perspective view of the assembled burner of Figure 4A;

Figure 5 shows a schematic diagram of an electrolysis apparatus according to a seventh embodiment of the present invention; and

Figure 6 shows a cross-sectional diagram of an exemplary electrolysis cell for used in the electrolysis apparatus of Figure 5.

Detailed Description

First Embodiment - weldinq/blazinq torch

Referring to Figure la there is shown a hydrogen and oxygen burner in the form of a welding or brazing torch 1 according to a first embodiment of the present invention. Torch 1 has a tapered chamber 2, with a base 2A having an oxygen inlet 3A,3B,3C,3D, and at least one oxygen exhaust aperture 4 at a chamber apex. A hydrogen feed pipe 5 passes through the tapered chamber 2 and has an outlet end 6 passing through the oxygen exhaust aperture 4. In use the oxygen and hydrogen being ignitable to create a flame extending from each oxygen exhaust aperture 4 and hydrogen feed pipe outlet end 6. The area of the feed pipe outlet end 6 through which hydrogen passes is substantially twice the area of the exhaust aperture through which oxygen passes. This is because twice the volume of hydrogen is required to mix with oxygen to create a clean burn into water vapour.

The feed pipe outlet end 6 extends just proud of the oxygen exhaust aperture. This ensures no hydrogen can enter into the chamber 2 causing a flash back, as there is always a positive pressure of oxygen leaking out of the exhaust aperture 4 preventing the hydrogen from entering the chamber.

The hydrogen feed pipe outlet end and oxygen exhaust aperture are both circular, and the feed pipe outlet is concentric with the oxygen exhaust aperture.

Feed pipe 5 also passes through the base 2A of chamber 2 to a hydrogen inlet 5A connected to a supply of hydrogen. An oxygen supply tube 7 is concentric with and surrounds feed pipe 5 and has one end connected to the perimeter of base 2A and the other end has an oxygen inlet 7A connected to a supply of oxygen which supplies oxygen to the oxygen inlet 3A,3B,3C,3D.

A moulded handle 8 may be surround oxygen supply tube 7.

To safeguard against flashback, or popping, the size of the feed pipe outlet end 6 is reduced in comparison to those featured in known burners. This may cause an increase in the discharge velocity of the hydrogen, and thereby further reduces the chances of it entering chamber 2. It is found that the gas passage of a feed pipe outlet end 6 having a cross-sectional diameter of equal to or substantially less than 0.25mm effectively eliminates flashback. Preferably the gas passage of the feed pipe outlet end 6 has a cross-sectional diameter of substantially 0.25mm.

The torch 1 can be used to weld or braze as is well known in the art.

Second Embodiment - weldinq/blazinq torch In some cases, the reduction in the gas passage of the feed pipe outlet end may restrict the quantity of hydrogen and oxygen deliverable by the touch. Thus, the burner may be provided with multiple chambers and/or multiple feed pipe outlet ends to compensate for the reduced output. Referring to Figures lb and lc there is shown a hydrogen and oxygen burner in the form of a welding or brazing torch lb according to a second embodiment of the present invention. In torch lb, the arrangement of the outlet ends 6b of the hydrogen feed pipes 5b and their respective oxygen exhaust aperture 4b, as well as their relative positions, are similar to that in torch 1 of the first embodiment. Moreover, the gas passage of each of the feed pipe outlet ends 6 has a cross-sectional diameter of substantially 0.25mm.

In contrast to torch 1 of the first embodiment, torch lb of the second embodiment comprises two identical chambers 2b each having four outlet end 6b I oxygen exhaust aperture 4b pairings. Furthermore, all of the outlet ends 6b of each of the chambers 2b are oriented in the same direction. As shown in Figure lb, the torch lb comprises an oxygen inlet 7b and hydrogen inlet 5b respectively connecting to an oxygen supply and a hydrogen supply, wherein the hydrogen feed pipe and oxygen supply tube coextend in the handle 8b before branching towards each of the chambers 2b. A safety valve 9 is provided at the hydrogen inlet for controlling/shutting off the flow of hydrogen.

As shown in Figure 1C, chambers 2b are cylindrical in shape and each has an end wall through which the four oxygen exhaust apertures 4a are opened in a quadrilateral arrangement. In other embodiments, each chamber may comprise any number of outlet end I oxygen exhaust aperture pairings in any arrangement, e.g. there may be three outlet end I O I QX exhaust aperture pairings provided at each chamber, arranged in-line or in a triangular arrangement.

The chamber 2b are angled to each other as shown in the plan view of Figure IB, e.g. the chambers are distributed around axis 0, such that during use the flame extending from the outlet ends 6 of the two chambers 2b converges towards a single point 0. Such an arrangement advantageously focuses the heat of the flame projected from the outlet ends 6 at the single point 0 and is particularly beneficial for welding torches. In other embodiments, the outlet ends of the two chambers may align along the same axis and direct towards each other.

Third Embodiment - boiler burner

Referring now to Figures 2A and 2B there is shown a hydrogen and oxygen burner in the form of a boiler burner 10.

Boiler burner 10 has a chamber 11 having an oxygen inlet 12. Chamber 11 has first and second opposing end walls 11A,11B spaced by side walls 11C,11D,11E,11F. A plurality of oxygen exhaust apertures 13 are in a rectangular array in the end wall 11A.

Second end wall 11B also forms part of a housing 14 supplying hydrogen through inlet 14A to a plurality of hydrogen feed pipes 15. One feed pipe 15 is provided for every oxygen exhaust aperture 13. The feed pipes 15 extend from end wall 11B.

When burner 10 is assembled, each feed pipe 15 passes through the chamber 11 and has an outlet end 15A passing through an oxygen exhaust aperture 13. The gas passage of each of the feed pipe outlet ends 6 has a cross-sectional diameter of substantially 0.25mm. In use the oxygen and hydrogen is fed to the inlet 14A and 12 respectively. Oxygen and hydrogen emerging from the feed pipe outlet end 15A and oxygen exhaust aperture 13 being ignitable to create a flame extending from each oxygen exhaust aperture 13 and hydrogen feed pipe outlet end 15A.

The area of the feed pipe outlet end through which hydrogen passes is substantially twice the area of the exhaust aperture through which oxygen passes, and the feed pipe outlet end extends proud of the oxygen exhaust aperture. The hydrogen feed pipe outlet end 15A and oxygen exhaust aperture 13 is circular, and the feed pipe outlet end 15A is concentric with the oxygen exhaust aperture 13.

Fourth Embodiment - boiler burner

Referring now to Figure 2C there is shown a hydrogen and oxygen burner in the form of a boiler burner 10b.

Boiler burner 10b comprises four chambers lib distributed around an axis 0, and wherein the outlet ends 15b of each chamber lib are arranged in a different orientation to the outlet ends 15b of at least another chamber lib. When fitted to a boiler, the axis 0 extends substantially in the horizontal direction. Such an arrangement allows the boiler burner 10b to concentrically extend inside a primary radial heat exchanger (not shown) of a commonplace boiler, e.g. the boiler burner 10b is arranged to replace a conventional gas burner unit in a commonplace boiler. More specifically, the radial distribution of the four chambers lib allows the resulting flame to heat different surfaces of the radial heat exchanger, thereby improving the efficiency of the boiler.

Each of the chambers lib is structurally similar to that employed in the boiler burner 10 of the third embodiment, e.g. the gas passage of each of the feed pipe outlet ends 15b has a cross-sectional diameter of substantially 0.25mm, except that nine feed pipe outlet end 15b and oxygen exhaust aperture 13b pairings are linearly spaced in a direction parallel to the axis. Therefore, the four chambers comprise thirty-six feed pipe outlet end 15b I oxygen exhaust aperture 13b pairings.

Furthermore, the hydrogen inlet 14b and the oxygen inlet 12b in this embodiment are provided at an end wall 11g of the housing 14c. More specifically, the hydrogen is supplied through the hydrogen inlet 14b to the housing 14c, through which it is distributed to the plurality of hydrogen feed pipes 15b. On the other hand, the oxygen inlet 12b sealingly extends through the housing 14c and opened to the chamber lib, through which oxygen is distributed to the plurality of oxygen exhaust apertures 13b.

The hydrogen inlet 14b and the oxygen inlet 12b of each of the chambers lib are respectively connected to a central oxygen supply line 50 and a central hydrogen supply line 60, through which they receive oxygen and hydrogen from gas supplies, e.g. gas supply outlets 280a, 280b of an electrolysis apparatus 200 as shown in Figure 5. The central oxygen and hydrogen supply lines 50, 60 are rigid pipes that provide structural support for the chambers lib and are fixed in place by a base plate 70. Thus, the boiler burner 10b can be fitted to a boiler by the base plate 70.

As shown in Figure 2C, the outlet ends 15b of each chamber lib are directed, at a non-zero angle, away from the axis O. Specifically, the four chambers lib are grouped into two pairs wherein the outlet ends 15b of a chamber lib in each pair are directed in an opposite direction to the outlet ends 15b of another chamber lib in the pair.

In some other embodiments, the four chambers are evenly distributed around the axis O, wherein the outlet ends of each chamber are directed radially away from the axis O.

Fifth Embodiment - cooker burner

Referring now to Figures 3A and 3B there is shown a hydrogen and oxygen burner in the form of a cooker burner 20.

Cooker burner 20 has a chamber 21 having an oxygen inlet 22. Chamber 21 has first and second opposing end walls 21A,21B spaced by circular wall 21C. A plurality of oxygen exhaust apertures 23 are in a circular array in the end wall 21A. Second end wall 21B also forms part of a circular housing 24 supplying hydrogen through inlet 24A to a plurality of hydrogen feed pipes 25 in a circular array. One feed pipe 25 is provided for every oxygen exhaust aperture 23. The feed pipes 25 extend from end wall 21B.

When burner 20 is assembled, each feed pipe 25 passes through the chamber 21 and has an outlet end 25A passing through an oxygen exhaust aperture 23. The gas passage of each of the feed pipe outlet ends 25A has a cross-sectional diameter of substantially 0.25mm. In use the oxygen and hydrogen is fed to the inlet 22 and 24A respectively. Oxygen and hydrogen emerging from the feed pipe outlet end 25A and oxygen exhaust aperture 23 being ignitable to create a flame extending from each oxygen exhaust aperture 23 and hydrogen feed pipe outlet end 24A.

The area of the feed pipe outlet end through which hydrogen passes is substantially twice the area of the exhaust aperture through which oxygen passes, and the feed pipe outlet end extends proud of the oxygen exhaust aperture. The hydrogen feed pipe outlet end 25A and oxygen exhaust aperture 23 is circular, and the feed pipe outlet end 25A is concentric with the oxygen exhaust aperture.

The number of hydrogen and oxygen outlets can be increased to provide a more even flame and this will be complimented with an increase in volume of hydrogen and oxygen by increasing the electrolytic cell gas outputs.

Sixth Embodiment - cooker boiler burner

Referring now to Figures 4A, 4B and 4C there is shown a hydrogen and oxygen burner in the form of a cooker / boiler burner 30.

Burner 30 has a chamber 31 formed from two half components 31A,31B having an oxygen inlet 32. Chamber 31 has first and second opposing end walls 31C,31D spaced by an octagonal side wall 31E. A plurality of oxygen exhaust apertures 33 are in a circular array in each side of the octagonal side wall 31C.

Inside chamber 31 is an octagonal housing 34 supplying hydrogen from inlet 34A (passing through chamber end wall 31D) to a plurality of hydrogen feed pipes 35 extending radially from each octagonal wall of housing 34. .One feed pipe 35 is provided for every oxygen exhaust aperture 33. The feed pipes 35 extend from each side wall of octagonal housing 34 in the same plane and angled to each other in the said plane. Such an arrangement may substantially result in a flame that projects in a circular pattern, which is particularly suitable for use in a cooker and/or a boiler.

When burner 30 is assembled, each feed pipe 35 passes through part of the chamber 31 and has an outlet end 35A passing through an oxygen exhaust aperture 33. The gas passage of each of the feed pipe outlet ends 35A has a cross-sectional diameter of substantially 0.25mm. In use the oxygen and hydrogen is fed to the inlet 32 and 34A respectively. Oxygen and hydrogen emerging from the feed pipe outlet end 35A and oxygen exhaust aperture 33 being ignitable to create a flame extending from each oxygen exhaust aperture 33 and hydrogen feed pipe outlet end 35A.

The area of the feed pipe outlet end through which hydrogen passes is substantially twice the area of the exhaust aperture through which oxygen passes, and the feed pipe outlet end extends proud of the oxygen exhaust aperture. The hydrogen feed pipe outlet end 35A and oxygen exhaust aperture 33 is circular, and the feed pipe outlet end 35A is concentric with the oxygen exhaust aperture 33.

Seventh Embodiment -

If desired the hydrogen and oxygen can be derived by electrolysis of water, e.g. using a fuel cell in reverse, applying electricity across the cell. This has the advantage that tanks of oxygen and nitrogen are not required and the apparatus can simply be powered by main electricity. Also electrolysis ensures the exact proportion of hydrogen and oxygen are produced to ensure clean combustion. Alternatively such an apparatus could be powered by green electricity devices, such as solar cells or wind generators or combinations thereof.

An embodiment of a novel electrolysis apparatus 200 is shown in Figure 5. The electrolysis apparatus 200 comprises a storage tank 210 in which stores a volume of water for supplying four electrolysis cells 100a, 100b, 100c, lOOd through a supply water outlet 212. The storage tank 210 further comprises a freshwater inlet 214 for replenishing any expensed water. The four electrolysis cells lOOa-d are in a parallel arrangement, each configured to electrolysis water into oxygen and hydrogen for fuelling the burner of any one of the first to the sixth embodiment.

An example of electrolysis cell 100 is shown in Figure 6. The electrolysis cell 100 is an asymmetric PEM electrolysis cell where during use a section 130 of the electrolysis cell containing the cathode is in absence of water. However, other types of PEM electrolysis cell, such as a classic electrolysis cell where both sections of the electrolysis cell are provided with water, are also applicable for use with the electrolysis apparatus 200.

Referring to Figure 6, the electrolysis cell 100 comprises a proton exchange membrane (PEM) 110. The PEM sealingly divides the electrolysis cell 100 into an anode section 120 and a cathode section 130. The anode section 120 contains an anode 122 arranged adjacent to the PEM and is electrically connected to a positive DC power supply, wherein the cathode section 130 contains a cathode 132 arranged adjacent to the PEM and is electrically connected to a negative DC power supply. The anode section 120 comprises a water inlet 104 for receiving water that is fed from a storage tank 210, e.g. a first or main compartment 210a of the storage tank 210, wherein the water in the anode section 120 is sealed from the cathode section 130.

During use, the anode 122 and cathode 132 are energised. This causes the anode 122 to oxidise the water in the anode section 120, and thereby generates oxygen gas, electrons and protons thereat. Subsequently, the protons are conducted through the PEM 110 to the cathode section 130 to combine with supplied electrons, thereby generating hydrogen gas at the cathode 132.

Since the PEM 110 is impermeable to gas, the hydrogen and oxygen are separated and are arranged to discharge through respectively a hydrogen discharge tube 134 and an oxygen discharge tube 124.

According to the present invention, the electrolysis cell 100 is in absence of a cooling means. Instead, the excess heat caused by the electrolysis process is removed by continuously discharging a portion of heated water, along with the oxygen gas, through the oxygen discharge tube 124. That is, generated oxygen gas entrains a portion of water as it exhausts from the anode section 120.

Referring back to Figure 5, the oxygen/water discharged from each of the electrolysis cells lOOa-d are collectively cooled by a first heat exchanger 220a before recycling back to the first or main compartment 210a of the storage tank 210. The first heat exchanger 220a is an air-water heat exchanger but in some other embodiments, the heat exchanger may be a vapour-compression refrigerator. The first heat exchanger 220a is configured to cool the recycled water to a temperature that is lower than the temperature (e.g. the operating temperature) in the electrolysis cells lOOa-d, preferably to substantially the ambient temperature, or below the ambient temperature, and in the process condenses water vapour in the oxygen gas.

Advantageously, the majority, or all, of the excess heat is removed from the electrolysis apparatus through the recycled water. If the recycled water is cooled below ambient temperature, it may further reduce the temperature of supply water that is fed to electrolysis cells lOOa-d. Thus, the operating temperature in the electrolysis cells lOOa-d can be regulated by varying the temperature and/or the quality of recycled water.

Similarly, the hydrogen gas discharged through the hydrogen discharge tube 134 is cooled by a second heat exchanger 220b before feeding into a second or auxiliary compartment 210b of the storage tank 210. In the illustrated example, the hydrogen is discharged in absence of any water, and therefore due to the reduced duty the second heat exchanger 220b is sized substantially smaller than the first heat exchanger 220a.

In some other embodiments, particularly those employing classic PEM electrolysis cells in which both the anode and cathode sections are filled with water, a portion of water in both the anode and cathode sections may be recycled to respective first and second compartments of the water storage tank, e.g. by respective oxygen and hydrogen discharge tubes.

In the illustrated example, the storage tank 210 comprises the first compartment 210a and the second compartment 210b for respectively receiving, in their headspaces, the discharged hydrogen and oxygen/water from the electrolysis cells lOOa-d. More specifically, the oxygen/water enters the first compartment 210a through an oxygen inlet 216a and the hydrogen enters the second compartment 210b through a hydrogen inlet 216b.

The first compartment 210a is also used for storing the water that is supplied to the electrolysis cells lOOa-d, and therefore it is arranged to have a larger capacity than the second compartment 210b. In the illustrated embodiment, the second compartment 210b also contains a volume of water for preventing the hydrogen gas from leaking back into the hydrogen discharge tube 134, e.g. the water acts as a water trap. In some other embodiments, the second compartment 210b may be in absence of water and serves only as a buffer tank for the hydrogen gas.

The oxygen inlet 216a and the hydrogen inlet 216b are located on the floor of their respective compartments and are each provided with a one-way valve to prevent the stored water from draining into the oxygen and hydrogen discharge tubes 124,134.

As the gases enter the storage tank 120, they bubble through the stored water to rise to their respective headspaces and thereby agitate the stored water. Advantageously such an arrangement aids the mixing of the recycled water and the stored water in the storage tank, thus promoting heat transfer therein.

The headspaces provided in the first and second compartments 210a, 210b serve as buffering volumes for the respective oxygen and hydrogen gases, and thus it helps mitigate fluctuations that may arise during gas generation and consumption.

The first and second compartments 210a, 210b are each provided with a gas outlet 218a, 218b for discharging the oxygen and hydrogen gases to respective gas driers 270a, 270b. The gas driers 270a, 270b may be any applicable gas driers, for example, silica gels. In use, the gas driers 270a, 270b reduce the humidity of the oxygen and hydrogen gases, thus the gases are conditioned for consumption at respective gas supply outlets 280a, 280b.

The gas supply outlet 280a, 280b may be connected to the oxygen and hydrogen inlets of a burner of each of the first to the sixth embodiments to form a burner system.

Ei Embodiment -

An embodiment of a novel electrolysis apparatus 300 is shown in Figure 7. The electrolysis apparatus 300 is functionally and structurally similar to the electrolysis apparatus 200, except that the hydrogen discharged from the electrolysis cells lOOa-d bypasses the storage tank 310 and is directly dried at the hydrogen drier 370b. For conciseness, like features are not described again.

In the illustrated embodiment, the hydrogen discharged from the PEM cells 100a- d is cooled at a heat exchanger 320b prior to entering the hydrogen drier 370b. This helps in condensing water vapours in the hydrogen gas and thereby reducing the drying load at the hydrogen drier 370b. However, in some other embodiments, the heat exchanger 320b may not be provided. Furthermore, in some other embodiments, the hydrogen drier 370b may not be provided and thus the hydrogen discharged from the PEM lOOa-d is directly discharged to the hydrogen outlet 380b for immediate consumption.

In the illustrated embodiment, the

tank 310

onlv a si

a volume of water that feeds the PEM cells lOOa-d, as well as the

water and

from the PEM cells tube 324. Similar to the

storage tank 310 serves as a buffering before it is dried at the

drier 370a and

tlet 380a for

The invention may take a form different to that specifically described above.

Further modifications will be apparent to those skilled in the art without departing from the scope of the present invention.

Claims

1. A hydrogen and oxygen burner comprising: one or more a chambers each having an oxygen inlet and at least one oxygen exhaust aperture; and a hydrogen feed pipe for each oxygen exhaust aperture, each feed pipe passing through the or each chamber and having an outlet end passing through an oxygen or hydrogen exhaust aperture, the area of the outlet end through which hydrogen passes having a cross-sectional diameter equal to, or less than, 0.25mm; wherein in use the oxygen and hydrogen being ignitable to create a flame extending from each oxygen exhaust aperture and hydrogen feed pipe outlet end.

2. The burner of claim 1, wherein the area of the feed pipe outlet through which hydrogen passes is substantially twice the area of the exhaust aperture through which oxygen passes.

3. The burner of claim 1 or claim 2, wherein the feed pipe outlet end extends proud of the oxygen exhaust aperture.

4. The burner of any one of the claims 1 to 3, wherein the hydrogen feed pipe outlet end and oxygen exhaust aperture is circular.

5. The burner of any one of the claims 1 to 4, wherein the feed pipe outlet is concentric with the oxygen exhaust aperture.

6. The burner of any one of the claims 1 to 5, wherein the chamber having a single exhaust aperture and a single feed pipe outlet.

7. The burner of any one of the claims 1 to 5, wherein the chamber comprises a plurality of exhaust apertures and a feed pipe outlet for each exhaust aperture.

8. The burner of claim 7, wherein the chamber comprises first and second opposing end walls spaced by side wall/s with said exhaust apertures in said first end wall, and said feed pipes extend from a second end wall and/or the side wall/s through the chamber and through the exhaust apertures in the first side wall, and optionally the second end wall and/or the side wall/s also forms part of a housing supplying hydrogen to the feed pipes and from which the feed pipes extend.

9. The burner of any one of the claims 1 to 8, comprises a plurality of chambers distributed around an axis, wherein the one or more outlet ends of each chamber are arranged in a different axial orientation to the outlet ends of at least another chamber.

10. The burner of claim 9, wherein the one or more outlet ends of each chamber are directed away from, or directed towards, the axis.

11. The burner of claim 7, wherein the chamber has first and second opposing end walls spaced by side wall/s with said exhaust apertures in one or more side wall/s, and said feed pipes extend through the exhaust apertures in the side wall/s, and optionally the feed pipes may extend from a housing in the chamber supplying hydrogen to the feed pipes and from which the feed pipes extend.

12. The burner of claim 11, wherein the outlet ends extend in the same plane and are angled to each other in the said plane.

13. A central heating boiler comprising the burner of any one of the claims 1 to 12.

14. A burner system, comprising the burner of claims 1 to 13 and the electrolysis apparatus of claims 1 to 8, wherein during use, the burner consumes the oxygen and hydrogen generated by the electrolysis apparatus to create a flame extending from each oxygen exhaust aperture and hydrogen feed pipe outlet end.

15. An electrolysis apparatus for generating oxygen and hydrogen, comprising: a storage tank for storing a volume of water; at least one electrolysis cell for electrolysing water fed from the storage tank to generate oxygen and hydrogen respectively at an anode and a cathode, the generated oxygen and hydrogen are separated by a proton exchange membrane and are arranged to discharge through respective oxygen and hydrogen discharge pipes, and wherein during use at least a portion of water in the electrolysis cell is arranged to recycle back to the storage tank by the oxygen discharge pipe; and a heat exchanger arranged externally to the electrolysis cell, the heat exchanger is configured to cool the recycled water.

16. The electrolysis apparatus of claim 15, wherein the storage tank comprises a first compartment and a second compartment each having a fluid inlet fluidly connected to respective oxygen and hydrogen discharge pipes, each of the first and second compartments is configured to receive the respective oxygen and hydrogen in their headspaces.

17. The electrolysis apparatus of claim 16, wherein the fluid inlets of the first and second compartments are arranged to submerge in the water stored in the water storage tank, and wherein during use the oxygen and hydrogen gases rise through the water to their respective headspaces.

18. The electrolysis apparatus of claim 16 or claim 17, wherein the oxygen and hydrogen in respective first and second compartments are sealed from each other.

19. The electrolysis apparatus of any one of claims 15 to 18, wherein the first and second compartments each comprises a gas outlet fluidly communicable with a respective gas drier for reducing the humidity of the oxygen and hydrogen gases.

20. The electrolysis apparatus of claim 15, wherein the hydrogen discharge pipe is directly connected to a gas drier for reducing the humidity of the hydrogen gas.

21. The electrolysis apparatus of claim 19 or claim 20, wherein each drier is fluidly connected to a respective gas supply outlet for outputting the oxygen and hydrogen from the electrolysis apparatus.

22. The electrolysis apparatus of any one of claims 15 to 21, wherein the at least one electrolysis cell comprises a plurality of electrolysis cells in a parallel arrangement.