A method and a device for producing hydrogen, and use of batch comprising metal-containing material

Abstract

Disclosed is a method for producing hydrogen by using metal as a catalyst, the method comprising providing a reactor (10) comprising an inlet for aqueous solution of organic acid, outlet for hydrogen (20) and a receiving part (12) for receiving metal-containing material, providing metal- containing material (14) to the reactor, providing an aqueous solution of organic acid to the reactor, contacting the metal- containing material and the organic acid to obtain a reaction mixture in the reactor (16), providing controllable external energy to directly heat the metal-containing material to adjust the temperature of the reaction mixture in the reactor to 90ºC or more, allowing the reaction mixture to react at the increased temperature to produce hydrogen, and recovering the hydrogen Disclosed is also a device for producing hydrogen by using metal as a catalyst, and use of a batch (14) comprising metal-containing material in a porous or permeable form and / or enclosed in a casing for producing hydrogen with the method.

Description

[0001] A method and a device for producing hydrogen, and use of batch comprising metal-containing material

[0002] Technical field

[0003] The present application relates to a method for producing hydrogen by using metal as a catalyst. The present application also relates to a device for producing hydrogen by using metal as a catalyst. The device may be used in the method. The present application provides use of a batch comprising metal-containing material in a porous or permeable form and / or enclosed in a casing for producing hydrogen with the method.

[0004] Background

[0005] The development of hydrogen economy has increased the need of applications utilizing hydrogen as well as applications for producing hydrogen. Hydrogen as a highly flammable gas however provides several safety issues, and storing and transporting of hydrogen are also problematic. It is difficult to reliably store hydrogen in tanks and convey in pipes, as hydrogen leaks easily and the transport requires complex and safe systems, which are expensive and slow and difficult to implement.

[0006] Also the production of hydrogen requires complex systems and extensive use of reagents and / or electricity. The reagents may be harmful and / or challenging to handle, and the systems may be large and not applicable to different targets.

[0007] There is need for simple, economically sound and safe methods and devices to produce hydrogen. It is also desired to obtain versatile systems for hydrogen production, which can be used in variety of hydrogen-utilizing applications.

[0008] Summary

[0009] The present invention can solve drawbacks of prior art and provide desired systems and methods for producing hydrogen. It was found out how to produce hydrogen quickly and in a safe manner, so that the produced hydrogen can be used immediately, such as in situ, and the production and usage can be controlled in real time. As hydrogen is a versatile energy carrier, the present methods and devices enable providing energy in a safe and simple manner into a variety of targets.

[0010] The present system and method can utilize a variety of metal-containing raw materials, which may be obtained for example from raw materials which are considered as waste material or otherwise as material with low value. There raw materials are safe to handle and can be formed into forms or shapes, which are easy to store, transport, handle and use.

[0011] The present application provides a method for producing hydrogen by using metal as a catalyst, the method comprising

[0012] -providing a reactor 10 comprising an inlet for aqueous solution of organic acid, outlet 20 for hydrogen and a receiving part 12, such as one or more receiving parts 12, for receiving metal-containing material, -providing metal-containing material 14 to the reactor,

[0013] -providing an aqueous solution of organic acid to the reactor,

[0014] -contacting the metal-containing material and the organic acid to obtain a reaction mixture in the reactor 16,

[0015] -providing controllable external energy to the metal-containing material to adjust the temperature of the reaction mixture in the reactor to 90°C or more, such as to 100°C or more, for example to the range of 110-170°C,

[0016] -allowing the reaction mixture to react at the increased temperature to produce hydrogen, and

[0017] -recovering the hydrogen.

[0018] The present application provides a device for producing hydrogen by using metal as a catalyst, the device comprising

[0019] -a reactor 10 for reaction mixture,

[0020] -an inlet for aqueous solution of organic acid,

[0021] -one or more receiving parts 12 for receiving one or more batches of metalcontaining material 14, wherein the reactor is arranged to contact the metalcontaining material and the organic acid to obtain a reaction mixture in the reactor 16, -controllable heating means arranged to heat the metal-containing material to adjust the temperature of the reaction mixture in the reactor to 90°C or more, such as to 100°C or more, for example to the range of 110-170°C,

[0022] -one or more sensor(s) for detecting the temperature of the reaction mixture, -an outlet 20 for hydrogen generated from the reaction mixture.

[0023] The present application provides use of a batch comprising metal-containing material in a porous or permeable form and / or enclosed in a casing for producing hydrogen with the method.

[0024] The main embodiments are characterized in the independent claims. Various embodiments are disclosed in the dependent claims. The embodiments and examples recited in the claims and the specification are mutually freely combinable unless otherwise explicitly stated.

[0025] The present method and device enable providing a fast, efficient and controllable catalytic method and device for producing hydrogen by using organic acid. When the metal-containing material is heated directly in the reactor, a fast control of the process, and a fast and efficient catalytic formation of hydrogen, are obtained. The process and the arrangement in the device also protect the delicate organic acid used in the method while allowing raising the temperature of the reaction mixture, more particularly the aqueous solution, to 90°C or more, which is exceptionally high temperature for processes using organic acids. The process can be carried out for a prolonged time with the provided organic acid.

[0026] As the present methods and systems utilize organic acids, and the use of strong acids or other harmful reagents is avoided, the system and method are safe and do not provide harmful waste, that should be specifically treated according to regulations and using complex and expensive methods and treatment systems.

[0027] The present method and device enables safe production of hydrogen at a desired location, which may be for example a vehicle or a location, such as an industrial plant or other site, wherein hydrogen is needed for example for production of electricity or as a fuel in an engine. The process and the device can be maintained by an end user. The present devices can be implemented in compact size and can be controlled and operated at various conditions and for a long time. For example the feed of reagents can be implemented in a safe, simple and controllable manner. Also the hydrogen outputted from the device, as well as outputted by-products can be controlled and directly conveyed to a desired target.

[0028] As the hydrogen production can be implemented at an immediate vicinity of a target utilizing the hydrogen, there is no need to store hydrogen for prolonged time in tanks or the like, or convey hydrogen via long pipes, i.e. a gas grid, to a remote target. This is advantageous as hydrogen gas tends to easily leak from containers and pipes and also dissolve in air, and the transport of hydrogen is problematic. Therefore by generating hydrogen in situ with the present method and device such operations can be avoided. As there is no need to store large quantities of hydrogen in storage tanks or transport the hydrogen to a remote location, the risk of explosions and other undesired effects related to storing hydrogen can be avoided..

[0029] Brief description of the drawings

[0030] Figure 1 shows an example of the reactor comprising a gas and liquid separation valve on to, an outlet valve at the bottom, and a socket for a cartridge comprising the metal-containing material on the side of the reactor,

[0031] Figure 2 shows a close view of the socket for receiving a cartridge comprising the metal-containing material.

[0032] Figure 3 shows a close view of a cartridge comprising the metalcontaining material inserted into the socket, wherein the socket is closed with a lid.

[0033] Figure 4 shows an example of a reactor comprising a plurality of raw material batches arranged in replaceable raw material containers, which are placed inside the reactor. Figure 5 shows an example of a reactor comprising a plurality of raw material batches arranged in closed raw material containers which are placed inside the reactor and wherein one or more batches can be released to the process.

[0034] Figure 6 shows a prototype of a reactor.

[0035] Detailed description

[0036] In this specification, percentage values, where applicable and unless specifically indicated otherwise, are based on weight (w / w, by weight, or wt%). In embodiments the open term “comprise” may be limited with a closed term “consisting of”.

[0037] The present application provides a method for producing hydrogen by using metal as a catalyst. The method may comprise or be a method for producing hydrogen at the site of use, such as in situ. The method may comprise or be a method for controlling the production and / or use of the hydrogen in real time. The site of use may be any site or application location disclosed herein, such as a vehicle, for example an aeroplane, a car, a truck, a heavy-duty vehicle, or a ship, or an industrial system, such as a system in a plant, in a factory or the like system or environment, which may be coupled to one or more other devices and / or device setups. The method may be carried out with the device disclosed herein and / or the device may be arranged to perform the method disclosed herein, such as wherein the control unit 30 is arranged to control the device to perform the method.

[0038] The method comprises providing a reactor 10, which may be any suitable reactor, such as a pressure reactor. The method may also comprise providing the device disclosed herein, the device comprising the reactor. The reactor comprises an outlet 20, preferably with a valve, for hydrogen and / or for other gases and / or vapour, preferably an inlet for aqueous solution of organic acid, outlet 22, preferably with a valve, for emptying the reactor, and a receiving part 12 for receiving metal-containing material 14. The receiving part may be an inlet for the metal-containing material, part of the inlet for the metal-containing material or connected to the inlet for the metal-containing material. The reactor may comprise any other required parts, such as one or

[0039] RECTIFIED SHEET (RULE 91) more of the parts disclosed herein. The reactor or the device may be a part of a system, which includes further parts, such as accessories, means for using the hydrogen, a vehicle, industrial devices and / or equipment and / or the like. The reactor or the device may be a part thereof or the reactor and / or the device may be integrated with, connected to or installed in such system or environment.

[0040] The reactor may have a volume, such as inner volume, which may refer to a volume of a reaction space, ranging from decilitres to hundreds of litres, such as 0.1-500 litres, for example 0.1-200 litres, 0.2-100 litres, 5-200 litres or 5- 100 litres. For example for portable use, such as in many types of vehicles, the reactor volume may be in the range of 0.1-10 litres, such as 1-10 litres 0.2-5.0 litres, 0.2-3.0 litres or 0.2-2.0 litres. In larger scale use, such as in industry and / or in large vehicles the reactor volume may be up to hundreds of litres, such as up to about 500 litres, up to about 200 litres, up to about 100 litres, or up to about 50 litres. However for safety reasons and / or for sake of efficiency and controllability about 100 litres, or about 50 litres, even about 20 litres, is a practical upper limit for most applications. In example a larger reactor may have a volume in the range of 5-200 I, 10-200 I, 5-100 I, 10- 100 I, 10-20 I, 5-50 I, 5-20 I or 5-10 I. A relatively small volume of the reactor enables implementing the device or the system in a compact form, which is portable and can be installed in existing systems. Also related accessories and controlling means, as well as loading of liquids and solids, can be implemented in such compact systems without problems. A reactor with a compact volume, such as 5-20 I or 10-20 I or other volume disclosed in previous, may be suitable for implementing a system in a vehicle, and / or for implementing a system comprising two or more reactors, which enable providing more reliable system which can allow a break in the function of one reactor. In examples the system comprises one or more reactors, such as two or more reactors, for example three, four, five or six. Similarly, the amount of systems may be two or more.

[0041] The method comprises providing metal-containing material to the reactor. The metal-containing material may be any suitable material which contains suitable metal, that reacts with the organic acid in the present method and device to produce hydrogen gas in desired amounts. The metal can act as a catalyst. The formation of hydrogen in the reaction of the metal with the organic acid may include formation of metal-O-CO-R complex, release of hydrogen, and any further reactions. The metal may be oxidized by a suitable oxidant, and reduced back to metal, which may be zero-valent metal, by the organic acid. However as the present process of hydrogen formation was unexpected, all the details of the reactions may not be known.

[0042] The metal-containing material may be recycled material, waste material, a by-product from a process, such as an industrial and / or mining process, or the like raw material. The raw material may be used as such, or it may be processed to obtain a batch or other suitable entity comprising the metalcontaining material. The raw material may be for example pressed into a form of a batch, which is an entity with a specific shape and / or a porous and / or degradable structure or otherwise permeable structure which allows the organic acid to react with an increased surface area of the metalcontaining material compared to solid structures of similar material having lower surface area. The batch may include material, which is degraded in the method, for example by the acid and / or by the increased temperature, wherein the permeability of the material is increased. For example metal such as magnesium may be provided and included in the batch to obtain degradability and / or permeability while also acting in the hydrogen production reaction.

[0043] The metal-containing material may comprise or substantially be or consist of metal, such as selected from one or more of iron, zinc, cobalt, copper, aluminium, nickel, magnesium, manganese. Metal alloys may be used, for example alloys comprising at least iron and / or other metals disclosed herein. Other metals may be also included. For example titanium was found to work efficiently in the test.

[0044] The metal-containing material may be selected from one or more of ore, mineral, waste material and / or recycled material. For example metalcontaining material obtained from mining industry can be used as raw material for preparing suitable batches of metal-containing material. Such material obtained from mining industry may be considered less valuable for the mining purposes, as the metals mainly contained in the material are not the ones desired in the mining, so the material may be considered as waste or by-product, such as metal waste and / or by-product metal. Similar material may be obtained from other industrial processes, recycling processes, and the like. Therefore the raw material can be inexpensive and the present method and processes can provide or be implemented in applications of circular economy, which are desired also for environmental reasons. It is also possible to separate metal(s) from the metal-containing material in the present process and / or in processes linked to it, for example by using electrolytic methods, and to recover the metal(s).

[0045] One embodiment comprises providing the metal-containing material as one or more batches. The batch 14 may comprise or be in a form of a bar, a rod, a sphere, a block, granules, powder, particles, pieces, and / or other entity and / or the batch may have a shape, such as a cartridge or the like, which may be designed to fit into a compatible receiving part 12, such as a socket, or other part comprising an aperture or a slot for the cartridge, such as shown in Figures 1-3.

[0046] The batch 14 may be in the form of one or more cartridges comprising the metal-containing material. A cartridge refers to an entity with a specific shape, which is configured to fit to a compatible receiving part. A plurality of cartridges may have same size and / or shape. The cartridges may be prepared and provided to the users of the present device, for example as commercial products, and they can be safely stored, handled, handled and used without causing harm to the user and without disintegrating the metal- contained material in the cartridge. The cartridge may contain other materials and / or parts, which can facilitate these effects. End user can easily and safely insert and / or remove the cartridges.

[0047] The cartridge may contain the material in a porous, permeable and / or degradable form and / or enclosed in a casing. The casing may comprise material, which is permeable, or may turn permeable in the method, for example by the effect of the acid. The casing may contain for example granules, powder, particles, pieces and / or other loose metal-containing material. The casing may also be an openable casing, which can be opened and / or closed in the method and / or in the reactor or device. For example the casing may include a hatch, which can be opened and / or closed by an actuator in the device, and / or which can be operated manually, so that the contact of the metal-containing material with the acid and / or the reaction mixture can be controlled. The casing may also include a permeable portion, such as on one side, which is perforated of contains a grill or the like structure allowing fluid connection to the metal contained in the casing.

[0048] The batch, such as the cartridge, may be designed or formed to fit to the one or more receiving parts for receiving one or more batches of metal-containing material, i.e. the batch and the receiving part are compatible with each other. The receiving part may comprise or be a compartment, a pocket, a container or the like shape designed to receive and preferably hold a dose of the metalcontaining material, which may be a batch. The receiving part may comprise or form a socket, which may be compatible with the shape of the batch. The receiving part may be open and / or openable and / or it may be closable.

[0049] Figures 1 and 2 show an example of a cartridge 14 in a form of a container, which can be closed with a cap 24 to obtain a closed cartridge / casing, which is open or permeable, or openable, at one and, i.e. at the end which is first inserted into the receiving part 12. The cartridge may be inserted into an aperture on the side of the reactor, which aperture opens into a receiving part 12 in a form of a socket. The receiving part is equipped with a heating means in a form of an induction coil 18 shown as a schematic drawing in figure 2. After the closed cartridge 14 is inserted into the socket 12, the socked is sealed with a cover 26. The socket 12 may contain an openable mechanism, which can be operated to open the socked to the reaction space to allow the solution to contact the cartridge, which is open at one side, so that the metal contained in the cartridge can react with the aqueous solution of organic acid. The cartridge may contain a part which allows pulling the cartridge from the receiving part, such as an aperture, a loop or a projection allowing grabbing the cartridge.

[0050] The batch inserted or applied into the receiving part, such as the socket, may remain in the receiving part. The receiving part(s) may be controllably connectable or openable to the reactor, i.e. to reaction space / inner volume, to contact or to allow contact of the metal in the batch with the aqueous solution of organic acid or the reaction mixture in the reactor and / or reaction space, such as one receiving part at a time and / or two or more receiving parts at a time.

[0051] The “connectable” refers to ability to bring the metal into liquid connection with the liquid in the reactor, such as in the reaction space. “Openable” refers to a possibility to open a space limited by the receiving part to the reactor or reaction space, for example where the receiving part comprises or is a container, such as a closable and / or openable container, socket, slot, aperture or the like formation or limited space.

[0052] The one or more receiving parts for receiving one or more batches of metalcontaining material may be in a form of one or more socket(s). The socked may be designed and / or arranged to receive the batch, such as the cartridge, i.e. the receiving part may contain a shape, wherein the batch is fitted.

[0053] The terms “openable and “closable” as well as “openability” and “closability” refer to the ability of the associated parts to be controllably opened and / or closed, such as by using an actuator and / or other mechanism able to open and / or close a structure, such as a hatch, lid, port or the like. Such action is preferably reversable so an opened structure can be closed and reopened, and vice versa. The opening and / or closing may be fully and / or partial, so it is possible to control the degree of opening / closing thus enabling control on the process and parameters thereof. The controlled opening and / or closing may be implemented by a control unit operably connected to the actuator or other mechanism. The same principle applies also to valves and the like inlets and outlets, which may be controllable and openable / closable and operatively controlled or controllable by the control unit.

[0054] In this way it is possible to control the method and / or reaction. For example the reaction may be initiated by contacting a batch with the acid, and / or the reaction rate may be controlled by contacting more batches with the acid / reaction mixture. It is also possible to lower the reaction rate or stop the reaction by closing the receiving part, so that a batch will no longer be in contact with the reaction mixture. This may be necessary for example if the reaction rate increases too much, or if a batch needs to be removed. Closing, i.e. sealing, the receiving part in the reactor side, i.e. in the reaction space, also allows removing the batch, if applicable. The reactor may comprise one or more holding means for holding one or more batches, and the holding means may be connected to one or more actuators arranged to move the holding means and / or the one or more batches. The actuator may be operatively connected to controlling means, and the actuator may be operated to move the holding means and / or the batch to move the batch to the reactor, to the reaction mixture and / or from the reactor and / or the reaction mixture. This enables controlling the process, and / or the reaction, for example by providing metal to the reaction to initiate and / or facilitate the reaction and / or by removing metal from the reaction to stop and / or to suppress the reaction.

[0055] Providing the metal in batches also enables directly heating the metal, which is more efficient, more controllable, more energy efficient and which also minimizes the effect of high temperature to the reaction mixture, such as to the organic acid. Batches can thus be controlled in several ways, such as by moving to and / or from the reaction mixture, by controllably heating with the external energy, and / or by moving into the reactor and / or out from the reactor. The process can also be controlled by the number of the batches provided to the reaction / reactor.

[0056] The receiving part, especially when in a form of a socket accessible from outside the reactor, shall also be closable or sealable from the ambient conditions, for example with a closable and / or sealable hatch or cap. Preferably the receiving part can be sealed in a manner enabling maintaining the pressure in the reactor. The receiving part especially shall be made of material which can tolerate the reaction conditions. The device may be partly of fully made of steel, for example at least the reactor may be made of steel, or any other suitable material, such as plastic, composite material , glass, and combinations thereof, which materials preferably are such grade that tolerate the present conditions, at least in the parts of the device which are exposed to said conditions. In one example at least the receiving part comprises or is made of glass, such as tempered glass. Tempered glass was found to tolerate the present conditions, such as high temperatures, acids and the like. The device or the reactor may comprise one or more receiving part(s) for receiving one or more batches of metal-containing material, wherein the device or the reactor is arranged to contact the metal-containing material and the organic acid to obtain a reaction mixture in a reaction space, preferably in a closed reactor.

[0057] The device or the reactor may comprise two or more receiving parts for receiving two or more batches of metal-containing material, arranged as an array of subsequent receiving parts 14 at least partly inside the reactor space, such as at the inner walls of the reactor space, for example at the inner walls of a circular reactor space, for example wherein the one or more batches of metal-containing material in the one or more receiving parts are replaceable and / or insertable during carrying out the method. Such examples are presented in figures 4 and 5.

[0058] The socket may be at an outer surface of the reactor, preferably in a form of one or more socket(s) arranged to receive one or more cartridge(s) comprising the metal-containing material in a porous or permeable form and / or enclosed in a casing, the socket(s) being sealable after inserting the batch to seal the reactor. The socket may be controllably openable to the reactor to allow contact of the metal in the batch with the aqueous solution of organic acid or the reaction mixture in the reaction space.

[0059] An example of a reactor comprising a plurality receiving parts each containing a raw material batch 14, is shown in Figure 4. The batches are arranged in replaceable raw material containers, which are placed inside the reactor 16, more particularly in the reaction space.

[0060] An example of a reactor comprising a plurality of receiving parts each containing a raw material batch arranged in closed raw material containers, wherein one or more batches can be released to the process when needed, is shown in Figure 5. One raw material batch 14 to be released at a time and the release order (the arrow) are marked in the figure.

[0061] The device or the reactor may comprise one or more sources of liquid to the reactor. A source of liquid may comprise one or more containers, such as tanks, for the liquid, which may be aqueous solution, such as the aqueous solution of organic acid. The source of liquid may be controllably connected to the reactor, for example by tubing. The system may contain one or more pumps, sources of pressure or the like means for inputting the liquid into the reactor, or the liquid container may be placed above the reactor to allow the liquid to flow to the reactor by effect of gravity. The container(s) may be replaceable, which allows easy maintenance of the process by an end user. The liquid container may comprise an inlet for liquid, such as aqueous liquid. For example recycled water from the process can be conveyed via the inlet to the container, preferably in a controlled manner to maintain the concentration of acid in a desired range. Also acid solution may be conveyed via the inlet.

[0062] The method comprises providing aqueous solution of organic acid to the reactor. The device or the reactor may comprise an inlet for liquid, such as the aqueous solution of organic acid, preferably from the liquid container. The inlet may comprise a valve, such as a controllable valve, for controlling the flow of the aqueous solution of organic acid. The inlet may be operatively connected to a control unit for controlling the inlet or providing of the aqueous solution of organic acid to the reactor. The inlet may also comprise an opening in an openable reactor, such as a lid, which may be closed to obtain a closed / sealed and / or pressurized reactor. A closed or sealed reactor, preferably a reactor which can tolerate pressure, is advantageous to maintain the formed hydrogen and possible water vapour in the reactor and to allow controlled release of the hydrogen and / or vapour from the reactor via a controlled outlet, such as a valve. However the present process can be also carried out in an open reactor, and / or at ambient pressure, such as at 1 bar. If pressure is formed in the reactor, it is more than 1 bar, such as 1 .5 bar or more, 2 bar or more, or 3 bar or more. The pressure in the reactor can be controlled by controllably releasing the hydrogen, vapour and / or other gases, such as oxygen, from the reactor.

[0063] The released water, which may be contained in vapour and / or which can be condensed, can be recycled. For example the released water from the reaction or reactor may be used or conveyed to be reused. This is especially advantageous in environments such as aeroplanes or other moving vehicles and / or isolated systems, especially if there is no suitable external water available. The concentration of the organic acid in the aqueous solution shall be high enough to enable the present method to proceed in a desired manner and to obtain the efficient production of hydrogen. The concentration of the organic acid in the aqueous solution of organic acid may be 10% by weight or more, such as 20% by weight or more or 30% by weight or more, for example 10- 40% by weight, 20-40% by weight or 10-30% by weight.

[0064] The organic acid may comprise any suitable organic acid, such as RCOOH and / or HCOOH, wherein R may represent any suitable side chain present in an organic acid. The organic acid may be selected from one or more of formic acid, acetic acid, citric acid, oxalic acid, butyric acid, lactic acid, maleic acid, and gluconic acid, and salts and / or combinations thereof. Acetic acid and citric acids were found to be most efficient acids for different uses, for example with iron and iron-containing materials. Oxalic acid was found to be useful in long-term use, and for example in combination with one or more other acid(s). Acids derived from treatment of organic waste, such as municipal waste, agricultural waste, food waste and the like are useful in the present method. This allows implementing the present method and device in waste treatment sites, such as plants. It was also found out that there was no need to degas the aqueous solution of the organic acid, i.e. the solution of organic acid may be undegassed.

[0065] The temperature of the reaction mixture, such as the aqueous solution comprising organic acid, shall be 90°C or more, as it was found out that temperatures of 80°C could not provide the desired rection speed and efficient production of hydrogen. The reaction efficiency is not linearly dependent on the temperature above 80°C. It was noted that high enough temperature of 90°C or more brought the efficiency to a completely different, higher level.

[0066] It was surprisingly found out that the used organic acids could tolerate high temperatures, such as higher than it is generally assumed for organic acids. No denaturing of organic acid was detected, or at least the exceptionally high temperature has no adverse effect to the organic acid was, or the adverse effect was minor and in practice not detectable. Temperatures higher than the thermal decomposition or denaturing temperature of each acid could be used for such acid. The reaction proceeded very efficiently and for a long time with the organic acids, such as for hours. Therefore using the high temperatures, especially when obtained by directly heating the metalcontaining material, could significantly enhance the production of hydrogen. The process can be run for at least 1 hour or more, 2 hours or more, 3 hours or more, 4 hours or more, or 5 hours or more. Addition of metal-containing material and / or acid may be required.

[0067] The method comprises providing controllable external energy to the metalcontaining material, preferably to the batch, to adjust the temperature of the reaction mixture in the reactor to 90°C or more. The adjusting may comprise increasing the temperature to and / or maintaining the temperature in a desired range. Suitable controllable heating means 18 is / are used. When the metal-containing material, i.e. the metal itself, was heated directly, instead of conducting temperature via the reaction solution or other ways, a very high efficiency could be obtained. Further, the reaction could be controlled with high accuracy, especially when fast heating means were used, such as induction arranged to adjust the temperature of the metal. The metal(s) act as conductor so that in induction eddy currents are instantly formed in the metal-containing material thus causing immediate heating. Preferably the metal-containing material comprises ferromagnetic and ferrimagnetic materials, such as iron.

[0068] The device or the reactor comprises controllable heating means arranged to heat the metal-containing material to adjust the temperature of the reaction mixture in the reactor, preferably to 90°C or more. The receiving part 12 may comprise the heating means 18, such as shown in Figure 2 (connections from the heating means not shown). The heating means may be arranged to surround the metal-containing material received by the receiving part, either fully or partly. For example an induction coil or other electrical heating element, such as in a form of a coiled wire, may be coiled, folded or otherwise arranged around a space in a receiving part arranged to receive the metal-containing material, such as the batch. In such way the heat generated by the heating means can be specifically directed to the metal, which makes the heating and controlling thereof very efficient. The surrounding environment and conditions have therefore minimal effect to the heating and controlling the heating / temperature. This arrangement also facilitates the use of the organic acid, as the acid solution is not used primarily as a medium for conducting the heat to the metal, but rather the acid solution is heated by the heated metal. The temperature of the metal may be higher than the general temperature of the surrounding liquid, which also has an impact to the efficiency of the method.

[0069] When compared to prior art methods and arrangements, wherein the reaction vessel as a whole is heated, for example with a thermal heating loop surrounding the reaction vessel, the present method and device were significantly more efficient in respect of the efficiency, controllability and speed. Higher temperatures could be maintained without deteriorating the organic acid, so the organic acid could maintain its activity for a prolonged time. It was possible to efficiently control the temperature of the reaction mixture by directly heating the metal-containing material. This caused indirect heating of the reaction mixture, which can be efficiently controlled.

[0070] The reactor may comprise one or more sealed through-holes for any required wiring, tubing or the like accessories. For example a heating means may be wired and connected to a source of energy such as electricity, and / or to a control unit outside the reactor.

[0071] The device or the reactor comprises one or more sensor(s) for detecting the temperature of the reaction mixture. The sensors may be wired and / or wireless. This enables controlling the temperature in the reaction space, i.e. the temperature of the aqueous solution, for example to adjust the heating means to (indirectly) adjust the temperature of the reaction mixture. The one or more sensors may be connected to the control unit, which may be arranged to control the heating means as feedback to the detected temperature(s) to (indirectly) adjust the temperature of the reaction mixture / acid solution to a desired value and / or range.

[0072] The device or the reactor may comprise a control unit 30 operatively connected to the source of external energy and arranged to control operation, level and / or type of the external energy to control the heating means and the temperature of the reaction mixture, pressure in the reactor and / or the reaction rate, optionally the electrolysis, to a desired range using information obtained from the one or more sensor(s) for detecting the temperature of the reaction mixture, one or more sensor(s) for detecting pressure of the reaction space, one or more sensor(s) for detecting pH of the reaction mixture, one or more sensor(s) for detecting redox potential of the reaction mixture, and / or from combinations thereof.

[0073] The device, the reactor and / or the system including the device, may include controlling means, which may be in a form of one or more control units 30. A control unit may include one or more processors, memory, user interface, display, keyboard, power connection, one or more physical connectors for connecting to external computerized devices, and / or network connection, such as wired or wireless connection. The control unit may contain a software configured to carry out one or more controlling actions, such as to control the devices connected to the control unit. The control unit may be connected to means for controlling and / or monitoring the one or more source(s) of external energy, one or more redox meter(s), one or more pH meter(s), one or more mixer(s), one or more pump(s), one or more valve(s), one or more actuator(s), and / or other device(s) and parts disclosed herein. The control unit may be arranged to operatively control one or more of controllable devices, such as energy sources, actuators and / or any other applicable devices or parts which may be operated by the control unit, as a feedback to one or more detected and / or measured value(s) to maintain the temperature, pH, pressure, or other feature at a desired level, such as at a predetermined range. The process parameters, such as the desired ranges, may be specified by an user, and / or they may be already programmed in the control unit, such as in the software. The control unit(s), device(s), sensor(s) and other electronic components may be connected by wiring and / or they may be wirelessly connected. The system is connected to a power source, such as a to a battery or a power network, to provide power for the energy source(s), control unit(s), electronics, meter(s), sensor(s), actuators, pumps and / or the like devices and components. The system may be arranged to automatically or semi-automatically carry out one or more of the methods or method steps disclosed herein.

[0074] One example provides a device for producing hydrogen by using metal as a catalyst, the device comprising -a reactor 10 for reaction mixture,

[0075] -an inlet for aqueous solution of organic acid, -one or more receiving parts 12 for receiving one or more batches of metalcontaining material 14, wherein the reactor is arranged to contact the metalcontaining material and the organic acid to obtain a reaction mixture in the reactor 16,

[0076] -controllable heating means arranged to heat the metal-containing material, -one or more sensor(s) for detecting the temperature of the reaction mixture, -one or more control units 30 arranged or configured to operatively control the controllable heating means to adjust the temperature of the reaction mixture in the reactor, preferably as feedback to the temperature detected by the one or more sensor(s) for detecting the temperature of the reaction mixture, to 90°C or more, such as to 100°C or more, for example to the range of 110-170°C, and

[0077] -an outlet for hydrogen generated from the reaction mixture preferably equipped with a valve.

[0078] The temperature of the reaction mixture and / or the aqueous solution can be controlled accurately as it is possible to stop the heating of the metalcontaining material immediately when necessary, and the metal-containing material may be even isolated from the reactor by using the closability function of the receiving part or other mechanism. These features also increase the safety of the method and system as in case of overheating or other problems the heating can be turned off immediately thus minimizing any further problems.

[0079] The temperature of the reaction mixture in the reactor could be increased to 100°C or more, preferably to 110°C or more. The temperature could be increased even up to about 200 °C, but for security reasons it was found out that temperature of about 170°C is a preferred upper limit for most applications. The temperature may be increased to the range of 100-170°C or 110-170°C, such as to the range of 110-150°C, to the range of 110— 140°C, to the range of 120-170°C, or to the range of 120-150°C. The range of 110-130°C was found advantageous for most applications in respect of efficiency, safety and controllability of the method and system.

[0080] It was found out that it may not be necessary to provide the external energy continuously after the reaction has started, as the reaction itself will release heat, which can maintain the temperature at the desired range. Therefore the method may comprise switching off the external energy after the desired temperature and / or reaction efficiency has been obtained.

[0081] The external energy may be provided to the metal-containing material by one or more controllable means for heating the metal-containing material, such as one or more induction elements, by one or more electrical heating elements, by heated medium and / or by one or more sources of infrared light. The external energy may be provided with a source of electricity and / or the external energy may be electricity. The source of external energy may comprise one or more portable sources, such as one or more batteries, one or more solar power units, such as photovoltaic / solar cells or thin-film solar cells, one or more wind power units, a generator, and / or other power sources such as a source of mains current and / or the like. A battery is suitable for portable systems, such as in vehicles. The process may be started with a portable energy source, such as the battery, and if the generated hydrogen is used for generating electricity, this electricity may be used as an additional energy source, and / or it may subsequently replace the battery as an energy source.

[0082] The external energy, or the means for heating the metal-containing material, may be controlled or controllable by a control unit operatively connected to the source of external energy. This may include adjusting the operation, level and / or type of the external energy as feedback to one or more features detected from the reactor, reaction space and / or reaction mixture / aqueous solution. For example by adjusting the power, i.e. the electricity, such as level of voltage, level of current, waveform, and / or by switching on and / or off, which is provided by the source of external energy to the heating means, it is possible to control and adjust the heating to obtain desired temperature in the reactor and / or in the solution in the reactor.

[0083] Preferably the external energy is induction directed to the metal-containing material, such as the batch or cartridge. The energy be provided to the metalcontaining material by one or more induction elements, which may comprise one or more induction coils, which include an electromagnet and an electronic oscillator that passes a high-frequency alternating current (AC) through the electromagnet. The rapidly alternating magnetic field penetrates the metal-containing material, generating electric currents inside the conductor called eddy currents. The eddy currents flow through the resistance of the metal-containing material, and heat it by Joule heating. Each receiving part may include a separate induction element, which may be separately controllable. For example a receiving part 12 may comprise an induction coil 18 arranged to heat by induction the metal-containing material received by the receiving part. The receiving part may be a container, such as a socker or the like, wherein an induction coil or other heating means may be coiler or otherwise arranged to surround the receiving part. Therefore it is possible to heat the metal-containing material inserted into the receiving part in most efficient way.

[0084] In one example the reactor comprises one or more induction coils as heating means arranged to directly heat the metal-containing material provided to the reactor, wherein the induction coil is connected to a source of electricity as external energy. The control unit is arranged to control the source of external energy to adjust the operation of the induction coil to control the heating of the metal-containing material and thus to control the temperature of the reaction mixture.

[0085] The heating means may comprise one or more electrical heating elements, which convert electrical energy into heat through the process of Joule heating in the element. Therefore the electrical heating elements are different from the induction elements. The electrical heating elements may be in the form of a wire, a tubular element or the like.

[0086] Heated medium may be provided by a heating element comprising a tube, which may be coiled or otherwise shaped to efficiently heat the target.

[0087] Any heating element may be further in the form of a coil, a sheet or any other form, which may be shaped or formed to surround and / or cover a location wherein the metal-containing material is placed. For example a receiving part may comprise and / or be formed with a heating element, such as a heating element may form or may be installed in the inner wall of a socket or other receiving means having inner wall(s). The heating element may also be at an outer wall of a receiving means. The method may comprise comprising providing further external energy in the form of electrolytic energy to the liquid and / or to the reaction mixture. The device may comprise electrodes connected or connectable to a controllable source of electricity for providing external energy in the form of electrolytic energy to the liquid / organic acid and / or to the reaction mixture. The electrodes may be present in the reactor, such as in the reaction space, and / or they may be installed in the receiving part(s).

[0088] Electrolysis, or electrolytic energy, can be used as a supporting form of energy in the present process. For example the reaction may be initiated by using a different form and application of energy, such as induction, which may be considered primary energy and which is not electrolytic energy, and it may be supported by electrolysis, which may be considered secondary energy, and / or electrolysis may be utilized after the process is stable and running. Electrolysis may be also used for separating one or more metals from the metal-containing material, which metals may be separated and recovered from the solution.

[0089] The method comprises contacting the metal-containing material and the organic acid to obtain a reaction mixture in the reactor, such as in a reaction space of the reactor, such as inside the reactor. This can be carried out by inserting one or more batches to the reactor, to the reaction space and / or opening a receiving part to allow the contacting and formation of the reaction mixture. This may be carried out by operating an actuator in the device, which may be controllable by a control unit or other controlling means.

[0090] The reaction space refers to the space inside the reactor containing the solution or the reaction mixture, or arranged to receive the solution or reaction mixture, and wherein the reactions may occur, at least partly. Also terms inner volume and / or solution space may be used. In the simplest arrangement the reaction space refers to inside the reactor, but the reactor may further contain other parts or compartments, such as the receiving parts, which may be isolated from the reaction space at least for a part of time, and which may decrease the inner volume of the reactor.

[0091] The reaction mixture refers to solution of the organic acid in contact with the metal. The metal may be released to the acid solution from the batch, such as fully or partly, and / or the metal may remain in the batch, at least partly, wherein the acid is penetrated in the batch and thus can access the metal in the porous or otherwise permeable batch and thus can react with the metal. The reaction mixture is formed when the acid contacts the metal-containing material. The reaction mixture may also contain hydrogen formed in the reaction and / or other agents.

[0092] The method may comprise closing the reactor, preferably closing in an airtight and / or pressure tolerant manner. As the formation of hydrogen will rise the pressure inside the reactor, it is preferred that the reactor can be properly sealed to avoid leakages. Especially it is not desired that the formed hydrogen gas leaks from the reactor, but it is desired that the hydrogen is controllably outputted via a hydrogen valve. It may be desired to monitor the conditions inside the reactor, especially the reaction space, such as temperature, pressure, pH, and the like. This can be implemented by including one or more sensors, preferably connected to a control unit.

[0093] The method comprises allowing the reaction mixture to react at the increased temperature to produce hydrogen. This may be carried out for a desired time, for example as a continuous process. The reacting may be carried out as long as reactive ingredients are available. However it is possible to provide a plurality of batches of metal-containing material, as discussed, and / or new batches may be added during the process. It is also possible to provide new aqueous solution of the organic acid, and / or other required ingredients if needed. It is also possible to discharge used materials from the reactor, for example by a valve and / or from the receiving parts during the process.

[0094] The reactor may comprise one or more valves in an outlet 22 for emptying the reactor, for example at the bottom of the reactor. Such a valve may be called as a discharge valve, and it may be designed to output liquid and / or solids, for example one or more valves may be designed to output liquid and / or one or more valves may be designed to output solids.

[0095] The method comprises releasing and / or recovering the hydrogen. This may be carried out by controlling an outlet valve in an outlet 20 for gases such as hydrogen and / or vapour generated from the reaction mixture. Such valve may be at the top or at the upper part of the rector, and it may be controllable, such as operatively connected to the control unit 30, which enables controllably releasing the hydrogen and preferably other gases / vapours. The hydrogen can be conveyed to desired location, such as with one or more pipes or tubes, for example to a container and / or for use, such as for direct use.

[0096] The outlet valve for hydrogen may be operatively connected to the control unit, preferably wherein the control unit is arranged to control the outlet valve based on information obtained from one or more sensors for detecting pressure, one or more sensors for detecting gas flow, and / or from combinations thereof.

[0097] The reactor may comprise one or more valves for separating gas and liquids, such as at the top of the reactor or at the upper part of the reactor. The valve may be for example a four-way valve, which in general has two flow positions, and usually a central position where all ports are closed.

[0098] Any of the valves or other inlets or outlets disclosed herein may be controllable and may be operatively connectable to the control unit 30 or controlling means. The valves or other inlets or outlets may comprise a controllable actuator for controlling thereof, such as for opening and / or closing the valve or other inlet or outlet, and / or controlling the flow rate of a liquid.

[0099] The method may comprise directly using the recovered hydrogen in a target, such as in a vehicle or in an industrial process, and / or with means for producing electricity. The target may comprise means for using the hydrogen, preferably means for directly using the hydrogen.

[0100] Hydrogen is considered an alternative vehicle fuel under the Energy Policy Act of 1992. The interest in hydrogen as an alternative transportation fuel stems from its ability to power fuel cells in zero-emission vehicles. A fuel cell may be two to three times more efficient than an internal combustion engine running on gasoline. Hydrogen can also fuel internal combustion engines.

[0101] The high cost of fuel cells and the limited availability of hydrogen vehicle fueling stations have limited the number of hydrogen -fueled vehicles in use today. Production of hydrogen-fueled vehicles is limited because people do not buy such vehicles if hydrogen refueling stations are not easily accessible. The present method and device can facilitate the hydrogen-fueled vehicles to gain popularity.

[0102] The device may be integrated or installed to a vehicle, such as in an aeroplane, in a car, in a truck, in a heavy-duty vehicle, in a train or in a ship. In practice any vehicle type which can utilize hydrogen as engine fuel, and / or for other purposes, such as for producing electricity, can utilize the present method and device. As the present device can be implemented in a compact form, which can be operated in a controlled manner, already existing vehicles can be modified to use the present method and device. For example the compact device having a reactor of few litres can be installed even in a compact car or the like vehicle, and the feed of the metal-containing material as well as the organic acid can be arranged in such manner that can be easily operated. For example organic acid can be added into a separate tank and the metal-containing material can be fed as batches into a dedicated feed system, which can receive a plurality of batches, and the use thereof can be arranged in a controlled manner so that batches are fed and / or provided to the reaction as needed. Alternatively large reactors can be installed in large vehicles, such as ships, aeroplanes and the like, for example more than one reactors, so the system is well scalable in a variety of targets and applications.

[0103] The device may be is integrated or connected to an industrial system, such as in a system in a plant or in a factory. Conventionally hydrogen may have been used in industry as mixed with natural gas, but many industrial operators prefer using pure hydrogen. The present method and devices are ideal to produce pure hydrogen in the location of use. There is no need to invest to expensive gas grids or the like infrastructure, but the present system can be implemented with low costs and in a short time to any existing industrial target. When using pure hydrogen without any natural gas, no rules and regulations relating to natural gas will apply, which makes the use of hydrogen also simpler in the respect of regulations and authorizations. Applicable industrial systems or industries include systems of steel industry, chemical industry, refiner industry (refineries), pulp and paper industry and the like.

[0104] The device may comprise or be integrated or connected to means for producing electricity, or to a system using the generated hydrogen for production of electricity. Electricity can be produced from hydrogen for example by using any suitable means, such as by using hydrogen fuel cells, by burning hydrogen in combustion gas turbines or by using other type of engine using hydrogen as fuel and operating a generator with the engine. The device may comprise or be integrated or connected to one or more fuel cells, one or more combustion gas turbines, one or more combustion engines, and the like, which turbines or engines may be connected to one or more generators for producing electricity.

[0105] Hydrogen fuel cells produce electricity by combining hydrogen and oxygen atoms. The hydrogen reacts with oxygen across an electrochemical cell similar to that of a battery to produce electricity, water, and small amounts of heat. Therefore the fuel cells are the green option. A fuel cell may comprise an anode, a cathode and an electrolyte membrane. The hydrogen travels through the anode of a fuel cell and oxygen goes through the cathode. At the anode, the hydrogen is split into electrons and protons. The protons move through the electrolyte membrane, while the electrons travel through a circuit, generating an electric current and excess heat. At the cathode, the protons, electrons, and oxygen combine to produce water molecules.

[0106] The method may comprise directly using the recovered hydrogen for production of electricity. The device may be arranged to directly use the recovered hydrogen for production of electricity. The “directly using / use” refers to using the hydrogen immediately after it is formed, i.e. without transporting the hydrogen to another location and / or without storing the hydrogen in a storage tank, especially an external storage tank or the like container, such as which is not part of the device or the system, for a prolonged time. However the system may include a buffer tank for the hydrogen, which can help balancing the production and usage, but which can be considered included in the direct use. The direct use may take place in the proximity of the present device / reactor. For example the means for producing the electricity or other means for directly using the hydrogen, may be directly connected to the present device / reactor, for example via a buffer tank, and the device / reactor and the means for directly using the hydrogen may form or be a part of a same system or device.

[0107] Disclosed is a vehicle, such as an aeroplane, a car, a truck, a train or a ship, and an industrial system, and means for producing electricity comprising the reactor and / or the device disclosed herein.

[0108] The applications and targets disclosed herein may include two or more of the devices or reactors, which can increase the efficiency and reliability of operation.

[0109] The present application provides use of a batch comprising metal-containing material in a form disclosed herein, such as in a porous or permeable form and / or enclosed in a casing, such as in a form of a cartridge, for producing hydrogen with the method disclosed herein.

[0110] Examples

[0111] Example 1

[0112] The effect of temperature to the formation of hydrogen was demonstrated by using open vessels, so that the bubbling caused by the formation of hydrogen could be visually detected from the aqueous solution. Acetic acid was used as the organic acid and iron based metal alloy was used as the metal-containing material.

[0113] An open vessel containing aqueous solution of the acetic acid and metalcontaining material was heated to 76.2°C. The temperature was determined by using a hand-held temperature meter. It was observed visually that the aqueous solution is slightly turbid, indicating a low level of reactions. The increase in bubbling was observed to be linear and not very extensive until slightly over 80°C. When the temperature was increased close to 90°C, the formation of hydrogen increased drastically causing the aqueous solution to bubble extensively. The hydrogen production continued for a long time indicating that the organic acid well tolerated the high temperature. When temperatures over 100°C were used, controlled conditions in a closed reactor were required because of extremely high gas production.

[0114] The same experiment was carried out by using other organic acids, including citric acid, oxalic acid and maleic acid. It was noted that acetic acid and citric acid were the most efficient acids when iron was the main metal.

[0115] Organic acids derived from treated municipal waste sludge were also tested with the present method. The acids included butyric acid, lactic acid and formic acid. Also these acids were useful in the present method.

[0116] Similar tests were carried out with variations, such as by adding the metalcontaining material to heated acid solution, or by heating the metalcontaining acid solution from the start. All the tests yielded similar results.

[0117] Example 2

[0118] An acid solution comprising acetic acid was combined with metal-containing material in a container. A variety of metals were used as the metal-containing material, including aluminium, copper, brass, alloys, tin, scrap metal and minerals. Electrodes connected to a power source were applied to the container to obtain electrolysis in the solution. It was observed that the reactions could be initiated at room temperature, even at 17°C, by the aid of electrolysis. Voltages starting from 1 .5 V up to 30 V and more were used, and no clear upper limit was found.

[0119] Example 3

[0120] A reactor for carrying out the present method was manufactured. The reactor had an inner volume of 10 litres and it corresponded to the reactor disclosed in figures 1-3. The reactor was prepared from steel, but the socket 12 for receiving the cartridge 14 comprising the metal-containing material was prepared from tempered glass, which was found to well tolerate the reaction conditions. The reactor included an induction coil as heating means 18 arranged to heat the cartridge inserted into the socket 12. Cartridges 14 comprising a casing were filled with different metal-containing materials, such as iron-containing granular mineral or pieces of recycled metal containing iron and other metals. For example tests were carried out by using pieces of tin cans, which are iron-based but contain other metals and other materials as well. Also these materials could be efficiently used. The cartridges 14 were inserted to the socket 12 as shown in the figures, and opened to allow the contact of acid in the reaction space with the metalcontaining material in the casing of the cartridge.

[0121] The reactor was small enough to be portable, and it could be easily installed to a suitable location, for example in a vehicle. The present reactions, such as disclosed in Example 1 , could be efficiently and controllably carried out in the reactor. For example, the temperature could be efficiently controlled with information obtained from a temperature sensor in the reactor, and the heating could be maintained in desired range by controlling the energy provided to the induction coil. A very high hydrogen production was achieved safely and controllably by using the reactor.

[0122] Example 4

[0123] A pressure reactor system for carrying out the present method is shown in Figure 6. The reactor is made of steel and it has an inner volume of 200 litres and it corresponds to the reactor disclosed in figures 1-3. The reactor is installed in a frame support in a pivoted manner.

[0124] The reactor assembly comprises a control unit 30 shown in left. Inside the reactor 10 an induction coil as heating means is arranged to directly heat the metal-containing material provided to the reactor, wherein the induction coil is connected to a source of electricity as external energy. The control unit is arranged to control the source of external energy to adjust the operation of the induction coil to control the heating of the metal-containing material and thus to control the temperature of the reaction mixture.

[0125] The reactor comprises an outlet 20 for the formed hydrogen at the top of the reactor, an inlet for aqueous solution of organic acid, a receiving part 12 for receiving metal-containing material (not shown in detail), and an outlet 22 at the bottom of the reactor for emptying the reactor.

Claims

Claims:

1. A method for producing hydrogen by using metal as a catalyst, the method comprising-providing a reactor (10), such as a pressure reactor, comprising an inlet for aqueous solution of organic acid, an outlet (20) for hydrogen and a receiving part (12) for receiving metal-containing material,-providing metal-containing material (14) to the reactor,-providing an aqueous solution of organic acid to the reactor,-contacting the metal-containing material and the organic acid to obtain a reaction mixture in the reactor (16),-providing controllable external energy to directly heat the metal-containing material to adjust the temperature of the reaction mixture in the reactor to 90°C or more, such as to 100°C or more, for example to the range of 110- 170°C,-allowing the reaction mixture to react at the increased temperature to produce hydrogen, and-recovering the hydrogen.

2. The method of claim 1 , comprising providing the external energy to the metal-containing material by one or more induction elements, by one or more electrical heating elements, by heated medium and / or by one or more sources of infrared light, such as providing the external energy with a source of electricity and / or wherein the external energy is electricity.

3. The method claim 1 or 2, comprising providing further external energy in the form of electrolytic energy to the organic acid and / or to the reaction mixture.

4. The method any of the preceding claims, comprising providing the metal-containing material as one or more batches, such as in the form of one or more cartridges comprising the metal-containing material in a porous or permeable form and / or enclosed in a casing, preferably in a permeable and / or an openable casing.

5. The method of any of the preceding claims, wherein the metal is selected from one or more of iron, zinc, cobalt, copper, aluminium, nickel, magnesium, manganese and titanium.

6. The method of any of the preceding claims, wherein the metalcontaining material is selected from one or more of ore, mineral, waste material and / or recycled material.

7. The method of any of the preceding claims, wherein the organic acid is selected from one or more of formic acid, acetic acid, citric acid, oxalic acid, butyric acid, lactic acid, maleic acid, and gluconic acid.

8. The method of any of the preceding claims, comprising directly using the recovered hydrogen in a target, such as in a vehicle and / or in an industrial process.

9. The method of any of the preceding claims, comprising directly using the recovered hydrogen for production of electricity.

10. A device for producing hydrogen by using metal as a catalyst, the device comprising-a reactor (10) for reaction mixture, such as a pressure reactor,-an inlet for liquid, such as aqueous solution of organic acid,-one or more receiving parts (12) for receiving one or more batches (14) of metal-containing material, wherein the reactor is arranged to contact the metal-containing material and the organic acid to obtain a reaction mixture in the reactor (16),-one or more sensor(s) for detecting the temperature of the reaction mixture, -an outlet (20) for hydrogen generated from the reaction mixture, preferably equipped with a valve, and-controllable heating means (18) arranged to directly heat the metalcontaining material to adjust the temperature of the reaction mixture in the reactor to 90°C or more, such as to 100°C or more, for example to the range of 110-170°C,11. The device of claim 10, wherein the controllable heating means (18) comprise one or more induction elements, one or more electrical heating elements, by one or more sources of microwaves, heated medium and / or one or more sources of infrared light, connected or connectable to a controllable source of external energy, such as a source of electricity.

12. The device of claim 10 or 11 , comprising electrodes connected or connectable to a controllable source of electricity for providing external energy in the form of electrolytic energy to the liquid and / or to the reaction mixture.

13. The device of any of the claims 10-12, comprising a control unit (30) operatively connected to the source of external energy and arranged to control the operation, level and / or type of the external energy to control the temperature of the reaction mixture, pressure in the reactor and / or the reaction rate, optionally the electrolysis, to a desired range using information obtained from the one or more sensor(s) for detecting the temperature of the reaction mixture, one or more sensor(s) for detecting pressure of the reactor, one or more sensor(s) for detecting pH of the reaction mixture, one or more sensor(s) for detecting redox potential of the reaction mixture, and / or from combinations thereof.

14. The device of any of claims 10-13, wherein the one or more receiving part(s) is / are controllably connectable or openable to the reactor to contact the metal with the aqueous solution of organic acid or the reaction mixture, such as one receiving part at a time and / or two or more receiving parts at a time.

15. The device of any of claims 10-14, wherein the device comprises two or more receiving parts for receiving two or more batches of metal-containing material, arranged as an array of subsequent receiving parts at least partly inside the reactor space, such as at the inner walls of the reactor space, for example at the inner walls of a circular reactor, for example wherein the one or more batches of metal-containing material in the one or more receiving parts are replaceable and / or insertable during carrying out the method.

16. The device of any of claims 10-15, wherein the one or more receiving parts for receiving one or more batches of metal-containing material are in a form of one or more socket(s) at an outer surface of the reactor, preferably in a form of one or more socket(s) arranged to receive one or more cartridge(s) comprising the metal-containing material in a porous or permeable form and / or enclosed in a casing, the socket(s) being sealable after inserting the batch to seal the reactor, and the socket being controllably openable to the reactor to allow contact of the metal in the batch with the aqueous solution of organic acid or the reaction mixture in the reactor.

17. The device of any of claims 10-16, wherein the device is integrated or installed to a vehicle, such as in an aeroplane, in a car, in a truck, in a heavy- duty vehicle, in a train or in a ship.

18. The device of any of claims 10-17, wherein the device is integrated or connected to an industrial system, such as in a system in a plant or in a factory.

19. The device of any of claims 10-18, wherein the device comprises or is integrated or connected to a system using the generated hydrogen for production of electricity.

20. The device of any of claims 10-19 arranged to perform the method of any of the claims 1-9.

21. Use of a batch comprising metal-containing material in a porous or permeable form and / or enclosed in a casing for producing hydrogen with the method of any of the claims 1 -9.

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