Microreactor and reactor for ammonia decomposition into hydrogen

Abstract

The invention concerns a microreactor (20) for ammonia decomposition into hydrogen comprising two reactive chambers in fluid communications with each other, said first and second reactive chambers being formed by - a first ammonia decomposition chamber (21) containing a cracking catalyst, and - a second heating chamber (22), * said microreactor (20) having an ammonia feeding inlet (102) connected to said first ammonia decomposition chamber (21) and an air feeding inlet (108) connected to said second heating chamber inlet, * said first ammonia decomposition chamber (21) having an hydrogen outlet (104) for carrying off generated hydrogen and an ammonia decomposition products outlet (211), * said second heating chamber (22) having a second heating chamber inlet (212) in fluid connexion with the ammonia decomposition products outlet (211), and a residues outlet (106) for carrying off residues out of the microreactor (20).

Description

Microreactor and reactor for ammonia decomposition into hydrogenTechnical domain

[0001] The present invention concerns the decomposition or thermomechanical cracking of ammonia (NH3) to generate hydrogen (H2). More precisely, the present invention relates to microreactor and reactors for ammonia decomposition into hydrogen. The invention also relates to system for generating electricity with hydrogen provided by such microreactor and reactor. Also, microreactors and reactors of the present invention can also implement ammonia decomposition generating hydrogen and further nitrogen.

[0002] Nowadays, hydrogen is foreseen to play and important role for the energy transition and decarbonize the heavy-duty sectors that are more difficult to be directly electrified. Ammonia has the potential to become one of the key hydrogen carriers due to has competitive properties regarding the energy density. Then, for certain applications where ammonia cannot be used directly in the end-applications, it is needed to decompose it and extract the hydrogen molecules that will be used in the last part of the value chain.

[0003] As an example, for a potential end-use application for the pure hydrogen produced, is the feeding of a PEMFC (Proton-Exchange Membrane Fuel Cells) without producing any degradation or damage coming from particles or elements non desirables that could be present in the hydrogen flow in really small quantities at the level of ppm (parts per million). Thus, ensuring high level of purity for the hydrogen extracted from the ammonia molecule could be critical for certain applications. Nowadays, hydrogen is foreseen to play and important role for the energy transition and decarbonize the heavy-duty sectors that are more difficult to be directly electrified.

[0004] There is a need to improve the available ammonia cracking technologies, so that it can be used in a very reliable and efficient way to produce and provide hydrogen on demand of a system, directly within or in connection to the system requiring hydrogen as energy provider. Supplying in a competitive way a good quality hydrogen with an ammonia decomposition process within or close to the hydrogen working system will provide advantages. This will be cost saving since ammonia has a 3.5 times higherN EOLO-1 -PCTenergy density than hydrogen and this also will give rise to less dangers to distribute and store ammonia with comparison to hydrogen.Related art

[0005] The ammonia decomposition technology is an existing method to extract hydrogen from the hydrogen carrier molecule in an endothermic reaction, where external energy has to be provided to the system to make the reaction happen. In the recent years, one field of research is focused on the development of new catalyst for the reactors to decompose the ammonia into hydrogen at lower temperatures, hence, reducing the energy requirements and improving the efficiency.

[0006] Another field of research for the ammonia cracking technology is focused on the development and optimization of the reactors systems minimizing the energy losses and deploying innovative heating systems to integrated with the reactor. However, to achieve certain hydrogen purities required by the industry and some devices as the fuel cells, it would be needed to go to much higher temperatures to achieve a higher conversion and even so we could not ensure that the hydrogen produced meets these strict requirements.

[0007] Then, until today, for large-scale industrial applications, purification methods such as PSA (Pressure Swing Adsorption) are being used, which are economical since the technology is highly developed and in a mature state, but they are not optimal to optimize the use of energy or space for applications such as on-board applications.

[0008] Then, other recent innovative solutions for the purification system and for the ammonia to hydrogen decomposition systems have been coming in parallel to increase the potential use of ammonia as an energy vector.Short disclosure of the invention

[0009] An aim of the present invention is the provision of a device that overcomes the shortcomings and limitations of the state of the art.N EOLO-1 -PCT

[0010] Another aim is to provide a device that can decompose the ammonia for extracting hydrogen, that device being versatile to be used in systems different in size and / or in available equipment, either for stationary or for mobile applications.

[0011] Another aim of the invention is to provide a more efficient way to decompose the ammonia for extracting hydrogen, regarding one or several of the following properties: the energy requirement, the reaction temperature and the hydrogen purity obtained.

[0012] Therefore, the invention aims to provide a device extracting hydrogen from the ammonia molecule in an efficient way, reducing the energy requirements and optimizing the energy flows within the device.

[0013] An aim of the present invention is the provision of a reactor that overcomes the shortcomings and limitations of the state of the art.

[0014] According to the invention, these aims are attained by the object of the attached claims, and especially by a microreactor for ammonia decomposition into hydrogen comprising two reactive chambers in fluid communications with each other, said first and second reactive chambers being formed by :- a first ammonia decomposition chamber containing a cracking catalyst, and- a second heating chamber,* said microreactor having an ammonia feeding inlet connected to said first ammonia decomposition chamber and an air feeding inlet connected to said second heating chamber inlet,* said first ammonia decomposition chamber having an hydrogen outlet for carrying off generated hydrogen, said and an ammonia decomposition products outlet,* said second heating chamber having a second heating chamber inlet in fluid connexion with the ammonia decomposition products outlet, and a residues outlet for carrying off residues out of the microreactor.

[0015] In this generic version of the microreactor according to the invention, there are the basic and needed elements to decompose the ammonia into hydrogen while initiating and maintaining a sufficiently high temperature in the first ammonia decomposition chamber. In that context, the microreactor according to the invention integrates a heating system, inN EOLO-1 -PCTthe form of the second heating chamber, to improve the reaction conditions in the most compact way possible

[0016] In a specific embodiment, the microreactor further comprises a separating membrane. More specifically, the following provisions take place :- said first ammonia decomposition chamber is divided by said separating membrane into two adjacent spaces, forming respectively a hydrogen production space containing said cracking catalyst, and a hydrogen purification space connected to said hydrogen outlet,- said separating membrane is able to filter elements contained in said hydrogen production space so as to let hydrogen to go through said separating membrane into said hydrogen purification space,- said ammonia feeding inlet is connected to said hydrogen production space,- said hydrogen outlet of said first ammonia decomposition chamber is connected to said hydrogen purification space,- said ammonia decomposition products outlet is connected to said hydrogen production space.

[0017] With this specific embodiment of the microreactor, this is possible to extract hydrogen from the ammonia molecule in an efficient way while keeping a high purity for the hydrogen generated at the outlet of the microreactor, namely the hydrogen outlet.

[0018] With respect to what is known in the art, this specific embodiment of the invention provides, among other, due to integration of the separating membrane in the same device than reaction chambers, advantage of obtaining a system as compact as possible, with high energy efficiency, low heat requirements and high ammonia to hydrogen conversion ratios.

[0019] This will therefore allow the running of the two main processes in the same microreactor, namely the ammonia decomposition reaction and the hydrogen separation and purification.

[0020] In a possible embodiment, the first ammonia decomposition chamber and the second heating chamber form two adjacent reactive chambers separated by a common separation wall which allow for heat generated in said second heating chamber to be transferred by said separation wall to said first ammonia decomposition chamber, therebyN EOLO-1 -PCTproviding heat to the ammonia cracking reaction taking place in the hydrogen production space. This provision is energy saving.

[0021] In a possible embodiment, the first ammonia decomposition chamber and the second heating chamber are flat shape reactive chambers, parallel to each other with a common separation wall (chamber separating wall), and said hydrogen purification space and said hydrogen production space form two superposed spaces parallel to each other and to said second heating chamber. This compact and flat arrangement provides advantages as described below in the present text.

[0022] In a possible embodiment, the microreactor further comprises along two opposite sides of said reactive chambers a hallway for gaseous exchange with said reactive chambers, wherein :- a first hallway comprises said ammonia feeding inlet which communicates only with said hydrogen production space, and said residues outlet which communicates only with said second heating chamber, and- a second hallway comprises said air feeding inlet communicating with said second heating chamber and with no communication with first ammonia decomposition chamber, and said hydrogen outlet which communicates only with said hydrogen purification space.

[0023] In this case, this is possible that said second hallway has a splitting wall spaced from said second heating chamber by a communicating room between said ammonia decomposition products outlet of said hydrogen production and said inlet of said second heating chamber.

[0024] In this case, this is also possible that said first ammonia decomposition chamber and said second heating chamber being divided into parallel channels separated from each other and extending between said first hallway and said second hallway.

[0025] In a possible embodiment, said air feeding inlet is connected to said second heating chamber inlet at the vicinity of said ammonia decomposition products outlet.

[0026] The microreactor according to the present invention is based on a type of technology different from the current state of the art focused onN EOLO-1 -PCTpacked bed reactors. This packed bed reactor technology has a heating section that is difficult to control to ensure that all flows are at the optimum temperature for the reaction, potentially making it less dynamic to changes in system state.

[0027] In a possible embodiment, the microreactor further comprises an additional chamber superposed to the second heating chamber containing a heating module able to provide heat to the additional chamber and transfer heat therefrom to the second heating chamber. This heating module can be an electric heater or any other type of heating source.

[0028] The invention also concerns a reactor for ammonia decomposition into hydrogen comprising several microreactors as described in the present text.

[0029] The invention also concerns a system for generating energy with hydrogen provided by one or several microreactors or by reactor as defined in the present text.Short description of the drawings

[0030] Exemplar embodiments of the invention are disclosed in the description and illustrated by the drawings in which:Figure 1 illustrates schematically several possible applications of the microreactors and reactors of the present invention;Figure 2 shows two possible mobile applications of the microreactors and reactors of the present invention, namely a mobile application into a heavy-duty fuel cell electric truck (on the right) and a stationary application into a hydrogen refuelling station (on the left);Figure 3A shows a perspective view of a first embodiment for the microreactor with a separating membrane, some of the walls (top wall and front wall) being transparent to see the inside arrangement of the microreactor;N EOLO-1 -PCTFigure 3B is a frontal projection view of the first embodiment of the microreactor of Figure 3A, in section;Figure 4 is a enlarged partial perspective view of the microreactor of Figures 3A and 3B;Figure 5A shows a perspective view of a second embodiment for the microreactor without any separating membrane, some of the walls (top wall and front wall) being transparent to see the inside arrangement of the microreactor;Figure 5B is a frontal projection view of the second embodiment of the microreactor of Figure 5A, in section;Figure 6 is an enlarged partial perspective view of the microreactor of Figures 5A and 5B;Figure 7 illustrates the stacking of microreactors according to the embodiments of Figure 3A or of Figure5A, so as to form a reactor according to the present invention;Figure 8 schematically represents a frontal partial view in section of the reactor of Figure 7 when stacked, for hydrogen generation applications and based on a microreactor according to the first embodiment and on catalytic oxidation heating system;Figure 9 schematically represents a frontal partial view in section of the reactor of Figure 7 when stacked, for gas mixture generation applications and based on a microreactor according to the second embodiment and on a catalytic oxidation heating system;Figure 10A represents a top view of one of the second heating chamber of the reactor of Figure 8, from arrow XB in Figure 8, for hydrogen generation applications and based on a catalytic oxidation heating system;Figure 10B represents a top view of one of the first ammonia decomposition chamber of the reactor of Figure 8, from arrow XC in Figure 8,N EOLO-1 -PCTfor hydrogen generation applications and based on a catalytic oxidation heating system;Figure 11 A is a block diagram of a possible heating system, integrated with an electricity generation system comprising a fuel cell system including a second purification step, where the first ammonia decomposition chamber generating the hydrogen includes a separating membrane, where the heat source for the reactor comes from the second heating chamber through a hybrid heating system (combination of catalytic burner and electric heating systems), showing the flow control systems regulating the gaseous flows between the system modules;Figure 11B is a block diagram of a possible heating system, integrated with an electricity generation system comprising a fuel cell system, where the first ammonia decomposition chamber generating the hydrogen has no separating membrane, where the heat source for the reactor comes from the second heating chamber through a hybrid heating system (combination of catalytic burner and electric heating systems), showing the flow control systems regulating the gaseous flows between the system modules;Figure 12 is a block diagram of the integration of a reactor according to the present invention in a system for generating energy where the first ammonia decomposition chamber generating the hydrogen includes a separating membrane, or generating a gas mixture without including the separating membrane, where the heat source for the reactor comes from the second heating chamber through an hybrid heating system (combination of catalytic burner and electric heating systems), and where the heat source to preheat the ammonia flow before the reactor inlet comes from an internal and external energy source, showing the flow control systems regulating the gaseous flows between the system modules;Figure 13A is a block diagram showing the same system as in Figure 12, in a higher-level view, with a simplified integrated reactor block diagram not showing the flow control systems regulating the gaseous flows between the system modules, and including elements related with the end use case for gas mixture and hydrogen supply mainly focus for stationary applications;N EOLO-1 -PCTFigure 13B is a block diagram, with a simplified integrated reactor block diagram not showing the flow control systems regulating the gaseous flows between the system modules, and including elements related with the end use case which is a mobility / on-board or stationary showing the same system as in Figure 12, in a higher-level view for a powertrain application;Figure 14A is a block diagram showing the same system as in Figure 13A, in a more simplified version, andFigure 14B is a block diagram showing the same system as in Figure 13B, in a more simplified version.Examples of embodiments of the present invention

[0031] With reference to figure 1, possible applications for a reactor 100 according to the present invention are illustrated. This shows the generation of hydrogen from the decomposition reaction of ammonia provides an interesting route to produce carbon-free hydrogen on-site and on-demand. On the left portion of Figure 1, upstream of the reactor 100, the ammonia NH3 is produced through an ammonia production module alimented by nitrogen N2, hydrogen H2 and energy. Downstream of the ammonia production module, the ammonia NH3 is supplied to an ammonia inlet 102 of the reactor 100. Alternatively, in a variant not shown, the ammonia NH3 is already produced and stocked in a tank connected to ammonia inlet 102 of the reactor 100.On the right portion of Figure 1, downstream of the reactor 100, there are two outlets for products produced by the reactor 100, namely a hydrogen H2 outlet 104 and an ammonia decomposition products outlet 106 which delivers notably nitrogen N2.

[0032] The hydrogen H2 outlet 104 can be used directly to supply some facilities that are very demanding in hydrogen H2, such as heavy industries that continuously require large amounts of hydrogen H2, or such as hydrogen H2 refueling stations. For other applications, the hydrogen H2 outlet 104 serves as hydrogen H2 source for a hydrogen internal combustion engine (Hydrogen ICE) or for a hydrogen fuel cell (Hydrogen FC), which can power vehicles using hydrogen, such as trucks, vessels, trains... (mobile application)N EOLO-1 -PCTor which can power other stationary installations such as data-centers, construction sites or power plant.

[0033] Two more detailed examples are shown in Figure 2, where the reactor 100 is located as the point of use of hydrogen. On the left part of Figure 2, this is a reactor 100 for a hydrogen refuelling station. On the right part of Figure 2, the reactor 100 is integrated in a vehicle, downstream of the ammonia tank and upstream of a fuel cell system powering the electric power train of the vehicle.

[0034] Therefore, thanks to the reactor 100, this is possible to bring ammonia NH3 as hydrogen energy carrier to the point of use.

[0035] Referring now to Figure 3A, 3B and 4, is shown a possible implementation of a first embodiment for a microreactor 20 according to the invention, with a separating membrane 50.

[0036] Basically, the microreactor 20 comprises two reactive chambers separated by a wall but in fluid communications with each other at their end, to allow a gas flow from one reactive chamber up to the other one. These two reactive chambers form a first reactive chamber and a second reactive chamber.

[0037] The first reactive chamber is a first ammonia decomposition chamber 21 where the reaction of ammonia decomposition and hydrogen separation will take place according to the following reaction:2NH3^ N2+ 3H2 (1)

[0038] In that first ammonia decomposition chamber 21, there is the separating membrane 50 and the correspondent catalyst 51. More precisely, the separating membrane 50 divides the first ammonia decomposition chamber 21 into two spaces, namely a hydrogen production space 21a, and a hydrogen purification space 21 b.

[0039] The hydrogen production space 21a contains the catalyst 51. The decomposition of ammonia occurs at high temperature in the presence of a catalyst 51. This catalyst 51 is preferably adapted for low-temperatureN EOLO-1 -PCTcracking of ammonia, namely the catalyst can react at a minimum temperature of 450°C, or even at 400°C.

[0040] This cracking catalyst 51 can comprises a support and at least one metal selected from ruthenium, nickel, rhodium, iridium, cobalt, iron, platinum, chromium, palladium, molybdenum, tantalum, copper, manganese and silver or Ce2O3.

[0041] This cracking catalyst 51 can be promoted with at least one metal selected from Li, Na, K, Rb, Cs, Mg, Ca, Ba, Sr, La, Ce, Pr, Sm, and Gd or with at least one of the material groups : transitions metal carbides and nitrides, alkaline earth metal amides and imides, and complex metal hydrides including NaAlH4, LiAlH4, Mg(BH4)2.

[0042] This cracking catalyst 51 can comprises a support containing at least one material selected from AI2O3, MgO, CeO2, ZrO2, La2O3, SiO2, Y2O3, TiO, TiCb, SiC, hexagonal BN (boron nitride), BN nanotubes, silicon carbide, one or more zeolites, LaAlCh, CeAlCh, Mg AbO4, CaAbO4, one or more carbon nanotubes, one or more carbon fibers, activated carbon, mesoporous silica and graphene.

[0043] During running of the ammonia decomposition reaction, the temperature in the hydrogen production space 21a is comprised between 200°C and 800°C in said hydrogen production space, said temperature in said hydrogen production space being preferably comprised between 400°C and 800°C.

[0044] Also, the ammonia decomposition rate is also affected by the pressure. In the present invention, the microreactor 20 operates at atmospheric pressure or almost atmospheric pressure as will be explained below, depending on the presence or the absence of the separating membrane 50. The pressure in the hydrogen production space 21a is in general between 100 000 Pa (1 bar) and 1 000000 Pa (10 bar), and between 200000 Pa (2 bar) and 10 000000 Pa (100 bar) in the presence of the separating membrane 50.

[0045] The hydrogen production space 21a contains also ammonia gas coming from the ammonia feeding inlet 102. This ammonia gas NH3 isN EOLO-1 -PCTcracked, thanks to catalyst 51 and sufficient temperature, into hydrogen H2 and nitrogen N2.

[0046] The separating membrane 50 can be a H2 permeable membrane made from palladium based material (Pd-based ceramic membrane or Pd- based metallic membrane), such as Pd-Cu, Pd-Au or Pd-Ag alloys, or made in a polymeric material of the following list : polysulfones, silicone rubbers, poly(vinylchloride), natural rubbers, polycarbonates, and polystyrenes, or made in a porous ceramic, such as a Pd-based ceramic material, or such as porous oxides including AI2O3 or ZrCh or made in a nickel based alloy or made in a porous stainless steel or made in Ni-Nb-Zr, or made with perfluorinated sulfonic acid, with polybenzimidazole or with proton conducting oxides including SrCeo.gsYbo.osCh-a, BaCeo.goNdo.ioCh-a, and SrZro.5Ceo.4Yo.1O3 a where a denotes the amount of oxygen vacancy.

[0047] The separating membrane 50 can be a hollow fiber membrane.

[0048] The separating membrane 50 can be associated to a porous support, forming thereby a supported membrane hollow fiber membrane. The porous support associated to said separating membrane 50 can be based on one of the following materials : AI2O3, stainless steel, metal, glass, ceramic, zeolite, and organic polymer or a mixture thereof.

[0049] The separating membrane 50 can be further associated to an intermediate layer based on one of the following materials: ceramic, vanadium oxide, nickel, and nitride.

[0050] The separating membrane 50 allows passage of hydrogen molecules H2 from the hydrogen production space 21a to the hydrogen purification space 21 b where pure hydrogen H2 is collected. Not all hydrogen H2 produced in the hydrogen production space 21a is filtered by the separating membrane 50 and passing through the hydrogen purification space 21 b. Therefore, in addition to nitrogen N2 and non-decomposed ammonia NH3, some hydrogen H2 also remains in the hydrogen production space 21a for further circulation in the microreactor 20.

[0051] In some cases, the said hydrogen purification space 21 b is further able to contain some generated nitrogen N2 resulting from the ammoniaN EOLO-1 -PCTdecomposition, and having passed through said separating membrane 50, and said hydrogen outlet 104 is able to carry off generated hydrogen and part of generated nitrogen N2 contained in said hydrogen purification space 21 b.

[0052] The hydrogen purification space 21 b extends along the separating membrane 50 on the side of the separating membrane 50 opposite to the hydrogen production space 21a. When the gas flow present in the hydrogen production space 21a goes forward from the inlet to the outlet hydrogen production space 21a, the decomposition reaction of ammonia runs, allowing passage of newly generated hydrogen molecules to pass through the separating membrane 50 and being collected on the hydrogen purification space 21 b. This pure hydrogen is then flowing to the hydrogen outlet 104 for evacuation out of the microreactor 20. The filtration by the membrane is forced thanks to a pressure difference. Generally, there exists a difference of pressure of at least 100 000 Pa (1 bar) between said hydrogen production space 21a and said hydrogen purification space 21 b, with a pressure in said hydrogen purification space 21 b lower than the pressure in said hydrogen production space 21a.

[0053] The second reactive chamber is a second heating chamber 22 where there is a production or supply of heat and the transfer of this thermic energy to the first ammonia decomposition chamber 21 through the wall separating these two chambers 21, 22. This energy provision is required to maintain a sufficiently high temperature in the first ammonia decomposition chamber 21, and more specially in the hydrogen production space 21a, to allow the reaction running for ammonia decomposition. This requirement derives from the fact that the ammonia decomposition process is an endothermic reaction, where a certain energy level has to be reached to begin the reaction and extract the hydrogen molecules, and also to keep the reaction running with time.

[0054] This heat can have several origin or sources.In an embodiment, the microreactor 20 further comprises a heating system arranged so that some heat can be brought to said hydrogen production space 21a, whereby the reaction of ammonia cracking can be initiated and maintained. Some examples of heating system arrangements with heat provided by the heating system supplied in the second heating chamber 22, are shown in figures 8 to 10 and will be described below in the text.N EOLO-1 -PCT

[0055] The outlet 211 of the hydrogen production space 21a (at the right side of figure 3B) communicates with the inlet 212 of the second heating chamber 22 (arrow A1) via a communicating room 213. This outlet 211 of the hydrogen production space 21a corresponds to the ammonia decomposition products outlet.This communicating room 213 forms a space extending along the second hallway 32 at the level of both the hydrogen purification space 21 b and the second heating chamber 22, between the latter and the air supply space 32a, via a splitting wall 213a extending from the separating membrane 50 level to the chamber separating wall 23 level but not at the second heating chamber 22 level. Also, this communicating room 213 communicates with the Outlet of the hydrogen production space 211, the Inlet of the second heating chamber 22 and with the air supply space 32a (at the right of figures 3A and 3B).

[0056] In other words, regarding the ammonia NH3 flow, the second heating chamber 22 is placed downstream the first ammonia decomposition chamber 21. This allows the heat present in the flow of gas going out the first ammonia decomposition chamber 21 at the location of the hydrogen production space 21a to be kept a while in the microreactor 20, i.e. in the second heating chamber 22, and contributing to the maintain of a sufficiently high temperature in the first ammonia decomposition chamber 21.

[0057] The inlet 212 of the second heating chamber 22 also receives an air supply through an air feeding inlet 108. The outlet of the second heating chamber 22 corresponds to the residues outlet 106. In the second heating chamber 22, there occurs a second ammonia decomposition reaction in the presence of hydrogen and oxygen gases present in the air coming from the air feeding inlet 108. Namely, the second ammonia decomposition reaction taking place in the second heating chamber 22 consists in the following exothermic reaction:2NH3+ H2+ 2O2^ N2+ 4H2O (2) one understands that the second heating chamber 22 forms a catalytic oxidation heating system.

[0058] Therefore, at the residues outlet 106, there are water H2O and nitrogen N2being delivered and which can also be salvaged for use.

[0059] To get a compact and stackable arrangement and more efficient heat conservation and reaction yield, the microreactor 20 has a flat geometryN EOLO-1 -PCTas can be seen in Figures 3 to 6. The first ammonia decomposition chamber 21 and the second heating chamber 22 are generally flat, with a polygon geometry outline which is rectangular in the figures. The first ammonia decomposition chamber 21 and the second heating chamber 22 are separated by a chamber separating wall 23. There is also a bottom wall 24 and a top wall 25 to delimit and close the external flat sides of the microreactor 20. In the present text, "top" and "bottom" terms are in accordance with the figures but could be inversed or could be placed left and right depending on the orientation of the microreactor 20.

[0060] In the preferred configuration shown in the figures, the first ammonia decomposition chamber 21 and the second heating chamber 22 are parallel to each other. This means that the separating membrane 50, the chamber separating wall 23, top wall 24 and bottom wall 25 are also parallel to each other.

[0061] Those flat and parallel configurations enable a maximum area for the separation surface between the first ammonia decomposition chamber 21 and the second heating chamber 22, namely a separating membrane 50 having a maximum extension between the first ammonia decomposition chamber 21 and the second heating chamber 22. This arrangement also contributes to have flowing duration time sufficient in both hydrogen production space 21a and second heating chamber 22 to obtain a maximum reaction yield. This arrangement also contributes to maximize the heat transfer between the second heating chamber 22 and the hydrogen production space 21, and also contributes to maximize the heat conservation in the micro reactor 20.

[0062] Thanks to the provision of coupling and integrating a heating space (second heating chamber 22) in the microreactor 20, forming a parallel space to the space where the main reaction happens (first ammonia decomposition chamber 21), this is possible to transfer the energy in a highly efficient manner. The energy needed to perform the ammonia decomposition and hydrogen separation will be reduced having both processes coupled in a single microreactor 20. Thus, that will reduce the overall heat requirements to run the microreactor 20 or any system with such a microreactor 20, thereby making the process more efficient from a thermodynamic point of view. This could potentially reduce the TCO (Total Cost of Ownership) at the time ofN EOLO-1 -PCTrunning system working with hydrogen generated from ammonia decomposition reaction using microreactors of the present invention.

[0063] The way to produce the heat in the second heating chamber 22 is based on a catalytic oxidation, where the non-pure hydrogen and the uncracked ammonia will be combined with oxygen taken from the air to generate the heat, water and nitrogen. Thus, the water and nitrogen produced could be released in the environment since there are not dangerous or harmful elements for the planet.

[0064] The supply and discharge of the different gases is arranged in two specific hallways extending along the whole length of two opposite sides of the microreactor 20.A first hallway 31 extends between the two ends of the side 26 of the microreactor (on the left of figures 3A and 3B), for the distribution of the ammonia NH3 and for the collect of the ammonia decomposition products produced and / or collected in the second heating chamber 22.A second hallway 32 extends between the two ends of a second side 27 of the microreactor (on the right of figures 3A and 3B), for the distribution of the air and for the collect of the hydrogen H2 produced in the first ammonia decomposition chamber 21 and collected in the hydrogen purification space 21 b.

[0065] The first hallway 31 is divided into two superposed spaces which are gaseous tight respective with each other and are not in communication, , being separated by a division wall 31c.There is an ammonia supply space 31a at the same level than the hydrogen production space 21a and communicating with the hydrogen production space 21a and with the ammonia feeding inlet 102. The ammonia supply space 31a does not communicate with (is gaseous tight with respect to) the hydrogen purification space 50, nor with the second heating chamber 22. There is also a residues discharge space 31 b at the same level than the second heating chamber 22 and communicating with the second heating chamber 22 and with the residues outlet 106. The residues discharge space 31 b does not communicate with (is gaseous tight with respect to) the hydrogen purification space 50, nor with hydrogen production space 21a.

[0066] The second hallway 32 is also divided into two superposed spaces which are gaseous tight respective with each other and are not inN EOLO-1 -PCTcommunication, being separated by a division wall 32c.There is an air supply space 32a at the same level than the second heating chamber 22 and communicating with the air feeding inlet 108 and with the inlet 212 of the second heating chamber 22 via the communicating room 213. The air supply space 32a is separated from the hydrogen purification space 21 b by the communicating room 213, the outlet 211 of the hydrogen production space and the separating membrane 50.There is also a hydrogen discharge space 32b at the same level than the Hydrogen purification space 21 b and communicating with the outlet 214 of the hydrogen purification space hydrogen and with the hydrogen H2 outlet 104.

[0067] Also, to direct the flows in the two reactive chambers between the first side 26 and the second side 27, said first ammonia decomposition chamber 21 and said second heating chamber 22 are divided into parallel channels 21c, 22c separated from each other by separating walls 21d, 22d for the separating walls of the second heating chamber 22 in figures 3A, 3B, 5A and 5B. These parallel channels 21c, 22c extend from the first side 26 of the microreactor to the second side 27 of the microreactor opposite to the first side 27. This first side 26 corresponds to the first hallway 31 location and the second side 27 corresponds to the second hallway 32 location. For the first embodiment, this applies also to both the hydrogen production space 21a and said hydrogen purification space 21 b.The parallel channels 21c in the hydrogen production space 21a allow gas flow from the first side 26 (first hallway 31) to the second side 27 (second hallway 32) of the microreactor 20.The parallel channels 22c in the second heating chamber 22 allow gas flow from the second side 27 (second hallway 32) to the first side 26 (first hallway 31) of the microreactor 20.

[0068] According to the first embodiment of the microreactor 20, thanks to the integration of the separating membrane 50 into the microreactor, the reaction can be performed at lower temperatures having the same conversion efficiency as at higher temperatures without the separating membrane 50. In other words, we can reach higher conversions efficiency by keeping the same operation temperature as without the separating membrane 50. That will also bring as an advantage regarding the heat and energy requirements as lower temperatures are sufficient to run in the optimal operation point the microreactor 20.Also, as previously mentioned, when operating with a separating membraneN EOLO-1 -PCT50, a difference of pressure should be created between :- the permeate (output flow in the hydrogen purification space 21 b that contains the pure hydrogen) and- the retentate (output flow in the hydrogen production space 21a that contains the uncracked ammonia, nitrogen generated and hydrogen that is not separated as the membrane has a specific efficiency and is not possible to recover the 100% of the hydrogen generated) flows. This pressure difference within the microreactor 20 is required to ensure a correct operability making possible to decompose the ammonia molecules and separating the hydrogen ones. That differences of pressure will be the main mechanism to allow the hydrogen molecules to be separated from the ammonia and nitrogen one in the first ammonia decomposition chamber 21 . Thus, the creation of optimal pressure in the microreactor 20 will favorable the hydrogen recovery factor that is one parameter assessing the performance of the membrane.

[0069] In this first embodiment of the microreactor 20, this is a microreactor with ammonia cracking reaction including a separating membrane 50 to obtain pure hydrogen or a hydrogen gas with high purity. The highly pure hydrogen will have to fulfil the standard requirements needed for specific applications as PEMFC (proton-exchange membrane fuel cell) to avoid producing damage or degradation of such systems. The first embodiment of the microreactor 20 with the integrated hydrogen purification function is able to generate in a one step process pure hydrogen.

[0070] Referring now to Figure 5A, 5B and 6, is shown a possible implementation of a second embodiment for a microreactor 20 according to the invention, without any separating membrane. In that situation, the first ammonia decomposition chamber 21 consists only in the hydrogen production space 21a, and there is no hydrogen purification space 21 b. Therefore, when changing the expression of "hydrogen purification space 21 b" by "hydrogen production space 21a," in the preceding text describing the first embodiment, this corresponds to the description of the second embodiment.

[0071] In this situation, the gas mixture flowing at the outlet of the hydrogen production space or ammonia decomposition products outlet 211 divides itself into two flows: one towards the Inlet 212 of the second heating chamber 22 and another second flow for the hydrogen discharge space 32b in direction to the hydrogen outlet 104.N EOLO-1 -PCT

[0072] Also, since there is no hydrogen purification, the hydrogen discharge space 32b and the hydrogen outlet 104 contain a gas flow with hydrogen but also with non-cracked ammonia and with nitrogen resulting from the ammonia decomposition reaction. In that situation, the hydrogen outlet 104 is to be understood as "gas mixture" outlet 104 (H2+ NH3+ N2).

[0073] The hallways 31 and 32, and the channel configuration 21c, 22c can be the same as in the first embodiment as visible in figure 5B.

[0074] In the figures 3A, 3B, 5A and 5B, the parallel channels 21c, 22c are rectilinear but they can have other shape, such as waves or zig zag.

[0075] In the configuration with channels 21c, 22c in the hydrogen production space 21a and in the second heating chamber 22, the operational point can be changed in a much faster way as the reaction is split in stacked microchannels, 21c, 22c. This also render possible to control much easier the flow, in a kind of discrete manner. That brings an advantage regarding the flexibility of operational points at different powers for the same system, being able to reduce and increase the hydrogen flow without having huge delays in the system response. This is different from the current stationaries systems based on a unique reactor volume, where the inertia of the whole system is lower due to the whole reaction happen in the same chamber, making it much more difficult to change the reactor state when is operating at a certain pressure, temperature and flow.

[0076] The microreactors 20 as described previously in accordance to the first or to the second embodiment can be used in a stacked configuration to form a reactor 100 as shown in figures 7 to 10.

[0077] These microreactors 20 (five microreactors 20 in the exploded view of Figure 7) are flat boxes with four holes opening the bottom wall 24 and four holes opening the top wall 25. More precisely, there are two holes at the end of each of the hallways 31, 32 for the same gas flow. Namely, for each end of the hallways 31, 32, there is one hole opening the bottom wall 24 and one hole opening the top wall 25. With that configuration, when two adjacent microreactors are stacked, the same holes of the two adjacent microreactors are coaxial and superposed and communicate together in a tight way, to form a continuous pipe from one microreactor to another one. These four holes present in the top wall 25 and in the bottom wall 24 of eachN EOLO-1 -PCTmicroreactor 20 are the ammonia feeding inlet 102 and the residues outlet 106 when considering the first hallway 31, and the air feeding inlet 108 and the hydrogen H2 outlet 104 when considering the second hallway 32.

[0078] With such an arrangement, some embodiments of the reactor 100 according to the present invention can be defined as a reactor for ammonia decomposition into hydrogen comprising several microreactors 20 as previously defined, wherein said microreactors 20 are stacked in a way wherein considering a pair of stacked microreactors 20, the second heating chamber 22 of one of the pair of microreactors 22 is superposed with the first ammonia decomposition chamber 21 of the other of the pair of microreactors 20, wherein the ammonia feeding inlet 102 of all the microreactors 20 are in fluid communication, and with a reactor ammonia feeding inlet, wherein the air feeding inlet 108 of all the microreactors 20 are in fluid communication, and with a reactor air feeding inlet, wherein the hydrogen outlet 104 of all the microreactors 20 are in fluid communication, and with a reactor hydrogen outlet, and wherein the residues outlet 106 of all the microreactors 20 are in fluid communication, and with a reactor residues outlet.

[0079] Therefore, this is possible to superpose inasmuch microreactors 20 as required to produce the hydrogen throughput needed for the application. A single microreactor 20 comprising the Second heating chamber 22 and the main reaction chamber (First ammonia decomposition chamber 21 where the ammonia is decomposed and separated into pure hydrogen) has a specific maximum flow and therefore to scale-up and reach high power requirements, it will be needed to have bigger flows. Then, a specific number of microreactors 20 stacked one on top of the other will form the final reactor system. In this way it will be possible to achieve different sizes and capacities for the reactor 100 as a combination of small microreactors 20 integrated together, where the way to manage different parameters of the reactions will be easier than in the case of having only one large size chamber where the reaction would take place.

[0080] With the integration of the heat source in a parallel chamber within the microreactor (second heating chamber 22), the heat can be transferred in a more efficient manner. Additionally, when stacking the plates (microreactors 20) the layout created will potentially allow to reduce the heatN EOLO-1 -PCTlosses in the reactor 100, having more available heat for the same energy input.Therefore, the global energy system will need a subsystem in charge of controlling the mass flows and energy flows of the different elements present in the different chambers, making possible the dynamic operation of the device fed with hydrogen, under specific power conditions and pure hydrogen requirements.

[0081] In the front sections of the reactors 100 illustrated in figures 8 and 9, respectively with and without a separating membrane 50, there is an additional chamber 22' superposed to the second heating chamber 22. As understood from the explanation above, the second heating chamber 22 forms a catalytic oxidation heating system. When need arise to have more heat supplied to initiate and / or to maintains a sufficient temperature in the hydrogen production space 21a, during some period of time, this additional chamber 22' is integrated in the microreactor 20 and contains a heating module able to provide heat to the additional chamber 22' and transfer heat therefrom to the second heating chamber 22 which temperature can be elevated or maintain at a value sufficient to have the decomposition reaction (1) running in the hydrogen production space 21a. Such a heating module can be an electric heating module. Alternatively, this heating module of the additional chamber 22' can be another type of heating module.The power of such a heating module (which varies depending on the size of the system) is less than 10 kWh / kilo of hydrogen produced per hour. Also, the electrical and catalytic requirements are balanced by taking into account the heat retained when the reactor is hot. This can be performed through a heat exchanger located at the reactor outlet and which serves to preheat the ammonia at the reactor inlet to reduce the heat requirement in the reactor (electrical and catalytic) to a maximum of 10 kWh / kgH2 / h.For start-up of the system, since there is no electricity generated (not yet, because there is no hydrogen), the system can be started on battery power (energy buffer that allows the system to be cold-started). The size of the battery varies with the power of the overall system. This battery also acts as a buffer if the system is connected to the local grid (e.g. solar panels, wind turbines) during periods of excess energy.

[0082] Figures 10A, 10B are views of the reactor of Figure 8, respectively section views from above the second heating chamber 22 and from above the first ammonia decomposition chamber 21. These figures show the inlets and outlets of the different gas flows.N EOLO-1 -PCT

[0083] The integration of a heating in the microreactor 20, through the second heating chamber 22, and eventually through the additional chamber 22' with the heating module, creates a more compact reactor or system. This allows reduction of the energy requirements and recirculation of the energy from the non-pure hydrogen and uncracked ammonia.In such an embodiment where there is an additional chamber 22' with a heating module, the reactor system incorporates a hybrid heating module comprising both electrical and combustion heat sources. During startup or low-temperature phases, the system uses electrical resistive heating elements embedded within or adjacent to the reactor housing to initiate ammonia cracking. Once the reactor reaches operational temperature, a portion of the ammonia and / or hydrogen tail gas is diverted to a combustion heating zone (second heating chamber 22) where heat is generated by oxidation / combustion to sustain the thermal environment, said combustion being implemented as catalytic oxidation (flameless combustion) and / or direct flame combustion, optionally assisted or stabilized by a catalyst and / or a flame holder.

[0084] Figures 11 A and 11 B illustrate schematically a possible solution for the system organising the control of the heat and energy required for and / or provided in the second heating chamber 22 and the additional chamber 22' with an electric heating module. Those figures show a situation where the system comprise a fuel cell using the hydrogen gas produced by the first ammonia decomposition chamber 21 for conversion of this chemical energy contained in this hydrogen gas into electricity, with the supply of oxygen of air. Those figures also show the flow control systems regulating the gaseous flows. This corresponds to a hybrid heating system (combination of catalytic oxidation burner the second heating chamber 22 and electric heating system in the additional chamber 22').In figure 11 A, this solution corresponds to the situation where the first ammonia decomposition chamber 21 generating the hydrogen includes a separating membrane 50. In figure 11 B, this solution corresponds to the situation where the first ammonia decomposition chamber 21 generating the hydrogen includes no separating membrane 50.In both situations, a H2 separation and purification unit 110 is preferably installed between the reactor and the fuel-cell, namely downstream of the reactor outlet 104. This H2 separation and purification unit 110 forms an optional purification module designed to remove residual ammonia, NOx, or other trace contaminants. This H2 separation and purification unit 110 may use a sorbent-based mechanism employing materials such as activated carbon,N EOLO-1 -PCTzeolites, or metal-organic frameworks. Such sorbing material(s) can be regenerated, and it will capture the ammonia residue (and maybe N2) from the uncracked reaction and unnecessary N2. This H2 separation and purification unit 110 forms a detachable module and can be bypassed entirely depending on the purity requirements of the downstream application (e.g., internal combustion engine, tolerant fuel cell).This H2 separation and purification unit 110 is particularly advantageous when a separating membrane 50 is not present, as this leads to a reactor outlet gas composition with a hydrogen H2 content that is lower than when a separating membrane 50 is present.In some embodiments, the system dynamically actuates the purification path and activates the H2 separation and purification unit 110 based on gas composition sensors. For example, if residual ammonia is detected above a predefined threshold, a diverter valve directs flow through the purification module formed by the H2 separation and purification unit 110. This modular architecture allows the same reactor core to serve multiple application domains.In figures 11A and 11B, the H2 separation and purification unit 110 is located between the reactor outlet 104 and the buffer tank which thereby receives more pure hydrogen to supply the fuel cell. This H2 separation and purification unit 110 is therefore located between the reactor outlet 104 and the fuel cell.

[0085] Figure 12 is another block diagram representation of a possible system for generating energy integrating a microreactor 20 or reactor 100 according to the present invention, according to the first embodiment where there is a separating membrane in the first ammonia decomposition chamber 21 or to the second embodiment where the first ammonia decomposition chamber 21 generating the hydrogen includes no separating membrane. This example also corresponds to a hybrid heating system (combination of catalytic oxidation burner the second heating chamber 22 and electric heating system in the additional chamber 22').This figure does not show any specific device of module for the use of the gas at the outlet 104.

[0086] Figures 13A and 13B are block diagrams showing the same system as in Figure 12, in a higher-level view, not showing the flow control systems regulating the gaseous flows between the system modules. Figures 13A and 13B also show the modules present in an integrated system comprising a microreactor 20 or a reactor 100 as described above.N EOLO-1 -PCTFigure 13A further shows the use of the gas at the outlet 104 of the reactor 100 as a gas supply that can be used for stationary applications.Figure 13B further shows the use of the gas at the outlet 104 of the reactor 100 as a gas supply for a powertrain (PWT) module.

[0087] In figures 12, 13A, 13B, the "gas mixture" relates either to pure hydrogen H2 if the reactor 100 is built with microreactors 20 comprising a separating membrane 50 or to a gas mixture if the reactor 100 is built with microreactors 20 having no separating membrane 50.

[0088] Figures 11 A, 11 B, 12, 13A and 13B could be amended according to variants where there is no additional chamber 22', namely no "electric heater", which means no hybrid heating system but heating only with the second heating chamber 22 corresponding to a catalytic oxidation.

[0089] Figure 14A is a highly simplified block diagram of Figure 13A showing the energy flows entering the reactor 100, and the use of the gas at the outlet 104 of the reactor 100 as a gas supply. This gas supply can be used for stationary applications.

[0090] Figure 14B is a highly simplified block diagram of Figure 13B showing the energy flows entering the reactor 100, and the use of the gas at the outlet 104 of the reactor 100 as a gas supply for a powertrain (PWT) system for stationary or mobile application.

[0091] For Figures 14A and 14B, this gas is either a hydrogen source when the reactor 100 contains a separating membrane, or a gas mixture (hydrogen, ammonia and nitrogen) when the reactor 100 contains no separating membrane.

[0092] In the context of the present invention, any one or several of the following provisions can be implemented for such a system for generating energy with hydrogen:- the system further comprises an ammonia tank in fluid connection with the ammonia feeding inlet of said reactor, and a first heat exchanger between said ammonia tank and the ammonia feeding inlet of said reactor, being able to bring heat to ammonia flowing from said ammonia tank to the ammonia feeding inlet of said reactor, said heat being provided by the gasN EOLO-1 -PCTflow conning from the reactor hydrogen outlet.- the system further comprises an hydrogen storage unit in fluid connection with the Hydrogen H2 outlet of the first ammonia decomposition chamber.- the system further comprises a second heat exchanger between said ammonia tank and the ammonia feeding inlet of said reactor, being able to bring heat to ammonia flowing from said ammonia tank to the ammonia feeding inlet of said reactor, said heat being provided by an external thermal energy source. This external thermal energy source can be any available heat from the stationary / on-board application not coming from the powertrain. *Example for stationary: Reactor used to generate hydrogen for a specific industrial process, where they have heat available from other processes and could be recovered and recirculate to the reactor to reduce the heat required to be generated into the second heating chamber.*Example for on-board: Reactor used in a container vessel to generate hydrogen, and some heat is available from other processes or system auxiliaries of the ship. Therefore, recovering that heat is possible to reduce the input heat requirements.- the system further comprises a powertrain fuelled by the hydrogen generated by the reactor and converting said hydrogen into kinetic energy or in electric energy. This powertrain can comprise a hydrogen internal combustion engine converting said hydrogen into kinetic energy. This powertrain can comprise a hydrogen fuel cell converting said hydrogen into electric energy. Said electric energy generated by said fuel cell can be supplied to at least one of the following devices: a motor, a drive unit, an electric battery of a mobile vehicle.- the reactor can be configured to be able to be mounted to a vehicle, including a terrestrial vehicle, such as a passenger vehicle or a heavy-duty truck, an aerial vehicle, an aquatic or maritime vehicle.- the system further comprises either a hydrogen internal combustion engine converting said hydrogen into kinetic energy and a dynamo converting said kinetic energy into electric energy, or a hydrogen fuel cell converting said hydrogen into electric energy wherein said electric energy powers a motor, a drive unit, an electric battery, an electric battery of a mobile vehicle, a computer device, a telecommunication devices, a storage device.

[0093] In the context of the present invention, the illustrated embodiments show a possible arrangement for the microreactor 20 where said first ammonia decomposition chamber 21 and said second heatingN EOLO-1 -PCTchamber 22 are superposed to form a multi-layered structure in a flat sandwich-like stacked structure.In another possible arrangement (not shown) of the microreactor 20, said first ammonia decomposition chamber 21 and said second heating chamber 22 are superposed to form a multi-layered structure in a coaxial and concentric tubular structure.With this concentric geometry alternative, according to a possible provision, the reactor 100 is such that:* said microreactors (20) are associated in a way wherein considering a pair of stacked microreactors (20), the second heating chamber (22) of one of the pair of microreactors (20) is superposed with the first ammonia decomposition chamber (21) of the other of the pair of microreactors (20),* the ammonia feeding inlet (102) of all the microreactors (20) are in fluid communication, and with a reactor (100) ammonia feeding inlet (102),* the air feeding inlet (108) of all the microreactors (20) are in fluid communication, and with a reactor air feeding inlet (108) ,* the hydrogen outlet (104) of all the microreactors (20) are in fluid communication, and with a reactor hydrogen outlet (104), and* the residues outlet of all the microreactors (20) are in fluid communication, and with a reactor residues outlet (106).

[0094] Such possible arrangement (not shown) of the microreactor microreactor (or a pair of stacked microreactors (20 as above)) with a multilayered structure in a coaxial and concentric tubular structure looks like tubes in tubes. In section, such a microreactor (or a pair of stacked microreactors (20) as above), would look like tree growth rings, and from the exterior, such a microreactor would look like a tube.

[0095] Such possible arrangement (not shown) of a tubular microreactor can apply for the implementation of a first embodiment for a microreactor 20 according to the invention, with a separating membrane 50.Such possible arrangement (not shown) of a tubular microreactor can apply for the implementation of a second embodiment for a microreactor 20 according to the invention, where the first ammonia decomposition chamber 21 generating the hydrogen includes no separating membrane 50.Such possible arrangement (not shown) of a tubular microreactor can apply for the implementation of an embodiment where there is an additional chamber 22' with a heating module: this additional chamber 22' with a heating module stays superposed to the second heating chamber 22 enablingN EOLO-1 -PCTT1 transfer of heat from the additional chamber 22' to the second heating chamber 22.

[0096] With such possible arrangement (not shown) of a tubular microreactor, when several (two or more) microreactors are combined, they may be fluidly connected in parallel and / or in series depending on the targeted performance. In a parallel configuration, the corresponding inlets are connected to a common supply manifold and the corresponding outlets are connected to a common collecting manifold, thereby increasing the overall hydrogen production capacity and flow rate in a compact and energyefficient manner. In a series configuration, the outlet of a first tubular microreactor is connected to the inlet of a subsequent tubular microreactor so as to increase the effective reactor length and / or residence time, thereby improving ammonia cracking conversion and / or reducing residual ammonia at the outlet. In further embodiments, the tubular microreactors may be arranged in a series-parallel network, for example by providing parallel branches each comprising two or more tubular microreactors in series. In all cases, fluid communication between corresponding inlets / outlets is provided through dedicated channels as defined in the present text.

[0097] Also, preferably, the reactor 100 is instrumented with a suite of temperature, flow, and gas composition sensors embedded at key zones. These enable closed-loop control of heating power, air injection, and reactant flow rates. In advanced embodiments, the system uses a model-predictive control algorithm derived from a high-fidelity 3D multiple physics simulation of the reactor 100.The digital model simulates thermal gradients, reaction kinetics, ammonia cracking performance, and pressure drops under varying load conditions. Control algorithms leverage this model to anticipate system behavior, optimizing energy input and maintaining hydrogen purity. Real-time software updates may adjust parameters based on catalyst aging, ambient conditions, or load transitions.The software control stack operates as a digital twin, providing predictive maintenance alerts, anomaly detection, and energy optimization. It is particularly beneficial in remote or mission-critical applications where downtime is costly.Software modules may be updated remotely to adapt to different use profiles or regulatory contexts.N EOLO-1 -PCTReference signs employed in the figuresMicroreactorFirst ammonia decomposition chamber a Hydrogen production space b Hydrogen purification space c Channels d Separating walls 1 Outlet of the hydrogen production space (ammonia decomposition products outlet) 2 Inlet of the second heating chamber 22 3 Communicating room 3a Splitting wall 4 Outlet of the hydrogen purification spaceSecond heating chamber c Channels d Separating walls ' Additional chamber with Heating moduleChamber separating wallBottom wallTop wall 25First side of the microreactorSecond side of the microreactor, opposite to the first sideFirst hallway a Ammonia supply space b Residues discharge space c Division wallSecond hallway a Air supply space b Hydrogen discharge space c Division wallN EOLO-1 -PCT50 Separating membrane51 Catalyst100 Reactor102 Ammonia feeding inlet104 Hydrogen H2 outlet106 Residues outlet108 Air feeding inlet110 H2 separation and purification unitA1 ArrowN EOLO-1 -PCT

Claims

Claims1. Microreactor (20) for ammonia decomposition into hydrogen comprising two reactive chambers in fluid communications with each other, said first and second reactive chambers being formed by- a first ammonia decomposition chamber (21) containing a cracking catalyst, and- a second heating chamber (22) ,* said microreactor (20) having an ammonia feeding inlet (102) connected to said first ammonia decomposition chamber (21) and an air feeding inlet (108) connected to said second heating chamber inlet,* said first ammonia decomposition chamber (21) having an hydrogen outlet (104) for carrying off generated hydrogen and an ammonia decomposition products outlet (211),* said second heating chamber (22) having a second heating chamber inlet (212) in fluid connexion with the ammonia decomposition products outlet (211), and a residues outlet (106) for carrying off residues out of the microreactor (20).

2. Microreactor (20) according to claim 1, wherein said first ammonia decomposition chamber (21) and said second heating chamber (22) are superposed to form a multi-layered structure either in a flat sandwich-like stacked structure or in a coaxial and concentric tubular structure.

3. Microreactor (20) according to claim 1 or 2, wherein* said first ammonia decomposition chamber (21) being divided by a separating membrane (50) into two adjacent spaces, forming respectively a hydrogen production space (21a) containing said cracking catalyst, and a hydrogen purification space (21 b),* said separating membrane (50) being able to filter elements contained in said hydrogen production space so as to let hydrogen to go through said separating membrane (50) into said hydrogen purification space (21a) , wherein said ammonia feeding inlet (102) is connected to said hydrogenN EOLO-1 -PCTproduction space, wherein said hydrogen outlet (104) of said first ammonia decomposition chamber (21) is connected to said hydrogen purification space (21a) , wherein said ammonia decomposition products outlet is connected to said hydrogen production space.

4. Microreactor (20) according to claim 3, arranged so that there exists a difference of pressure of at least 100000 Pa (1 bar) between said hydrogen production space (21 b) and said hydrogen purification space (21a) , with a pressure in said hydrogen purification space (21a) lower than the pressure in said hydrogen production space.

5. Microreactor (20) as in any of claims 1 to 4, wherein it further comprises a heating system arranged so that some heat can be brought to said hydrogen production space, whereby the reaction of ammonia cracking can be initiated and maintained.

6. Microreactor (20) as in preceding claim, wherein the heating system allows a temperature comprised between 200°C and 800°C in said hydrogen production space, said temperature in said hydrogen production space (21 b)being preferably comprised between 400°C and 800°C.

7. Microreactor (20) as in any of claims 1 to 6, wherein said first ammonia decomposition chamber (21) and said second heating chamber (22) are divided into parallel channels separated from each other and extending from a first side of the microreactor (20) to a second side of the microreactor (20) opposite to the first side.

8. Microreactor (20) as in any of claims 1 to 7, wherein said first ammonia decomposition chamber (21) and second heating chamber (22) form two adjacent reactive chambers separated by a common separation wall which allow for heat generated in said second heating chamber (22) to be transferred by said separation wall to said first ammoniaN EOLO-1 -PCTdecomposition chamber (21), thereby providing heat to the ammonia cracking reaction taking place in the hydrogen production space (21 b).

9. Microreactor (20) as in any of claims 1 to 8, wherein said cracking catalyst comprises a support and at least one metal selected from ruthenium, nickel, rhodium, iridium, cobalt, iron, platinum, chromium, palladium, molybdenum, tantalum, copper, manganese and silver or Ce2O3.

10. Microreactor (20) as in preceding claim, wherein said cracking catalyst is promoted with at least one metal selected from Li, Na, K, Rb, Cs, Mg, Ca, Ba, Sr, La, Ce, Pr, Sm, and Gd or with at least one of the material groups : transitions metal carbides and nitrides, alkaline earth metal amides and imides, and complex metal hydrides including NaAlHzi, LiAl F , Mg(BH4)2.1 1. Microreactor (20) as in claim 9 or 10, wherein the support comprises at least one material selected from AI2O3, MgO, CeO2, ZrO2, La2O3, SiO2, Y2O3, TiO, TiCh, SiC, hexagonal BN (boron nitride), BN nanotubes, silicon carbide, one or more zeolites, LaAlCh, CeAlCh, Mg AI2O4, CaAbOzi, one or more carbon nanotubes, one or more carbon fibers, activated carbon, mesoporous silica and graphene.

12. Microreactor (20) as in claim 3, wherein said separating membrane (50) is a H2permeable membrane made from palladium based material, such as Pd-Cu, , Pd-Au or Pd-Ag alloys, or made in a polymeric material of the following list : polysulfones, silicone rubbers, poly(vinylchloride), natural rubbers, polycarbonates, and polystyrenes, or made in a porous ceramic, such as a Pd-based ceramic material, or such as porous oxides including AI2O3 or ZrO2or made in a nickel based alloy or made in a porous stainless steel or made in Ni-Nb-Zr, or made with perfluorinated sulfonic acid, with polybenzimidazole or with proton conducting oxides including SrCeo.gsYbo.osC -a, BaCeo.goNdo.-ioC -a, and SrZro.5Ceo.4Yo.1O3 a where a denotes the amount of oxygen vacancy.N EOLO-1 -PCT13. Microreactor (20) as in claim 3, wherein said separating membrane (50) is a hollow fiber membrane.

14. Microreactor (20) as in any of claims 12 to 13, wherein said separating membrane (50) is associated to a porous support, forming thereby a supported membrane.

15. Microreactor (20) as in claim 14, wherein said porous support associated to said separating membrane (50) is based on one of the following materials: AI2O3, stainless steel, metal, glass, ceramic, zeolite, and organic polymer or a mixture thereof.

16. Microreactor (20) as in claim 14 or 15, wherein said separating membrane (50) is further associated to an intermediate layer based on one of the following materials: ceramic, vanadium oxide, nickel, and nitride.

17. Microreactor (20) as in claim 3, wherein said first ammonia decomposition chamber (21) and second heating chamber (22) are flat shape reactive chambers, parallel to each other with a common separation wall, and wherein said hydrogen purification space (21a) and said hydrogen production space (21 b) form two superposed spaces parallel to each other and to said second heating chamber (22).

18. Microreactor (20) of claim 8, wherein it comprises along two opposite sides of said reactive chambers a hallway for gaseous exchange with said reactive chambers, wherein :- a first hallway (31) comprises said ammonia feeding inlet (102) which communicates only with said hydrogen production space (21a), and said residues outlet (106) which communicates only with said second heating chamber (22) , and- a second hallway (32) comprises said air feeding inlet (108) communicating with said second heating chamber (22) and with no communication with first ammonia decomposition chamber (21) , and saidN EOLO-1 -PCThydrogen outlet (104) which communicates only with said hydrogen purification space (21a) .

19. Microreactor (20) of claim 18, wherein said second hallway has a splitting wall spaced from said second heating chamber (22) by a communicating room between said ammonia decomposition products outlet (211) of said hydrogen production space (21a) and said inlet of said second heating chamber (22) .

20. Microreactor (20) of claim 18, wherein said first ammonia decomposition chamber (21) and said second heating chamber (22) being divided into parallel channels separated from each other and extending between said first hallway (31) and said second hallway (32).

21. Microreactor (20) as in any of claims 1 to 20, wherein said air feeding inlet (108) is connected to said second heating chamber inlet (212) at the vicinity of said ammonia decomposition products outlet (211).

22. Microreactor (20) as in claim 3, wherein said hydrogen purification space (21a) is further able to contain some generated nitrogen resulting from the ammonia decomposition, and having passed through said separating membrane (50) , and wherein said hydrogen outlet (104) is able to carry off generated hydrogen and generated nitrogen contained in said hydrogen purification space (21a) .

23. Microreactor (20) as in any of claims 1 to 22, wherein it further comprises an additional chamber (22') superposed to the second heating chamber (22) containing a heating module able to provide heat to the additional chamber (22') and transfer heat therefrom to the second heating chamber (22).

24. Microreactor (20) as in claim 23, wherein said heating module is an electric heater.N EOLO-1 -PCT25. Reactor (100) for ammonia decomposition into hydrogen comprising several microreactors (20) as in claims 1 to 24.

26. Reactor (100) for ammonia decomposition into hydrogen comprising several microreactors (20) as in claim 8, wherein said microreactors (20) are stacked in a way wherein considering a pair of stacked microreactors (20), the second heating chamber (22) of one of the pair of microreactors (20) is superposed with the first ammonia decomposition chamber (21) of the other of the pair of microreactors (20), wherein the ammonia feeding inlet (102) of all the microreactors (20) are in fluid communication, and with a reactor (100) ammonia feeding inlet (102), wherein the air feeding inlet (108) of all the microreactors (20) are in fluid communication, and with a reactor air feeding inlet (108) , wherein the hydrogen outlet (104) of all the microreactors (20) are in fluid communication, and with a reactor hydrogen outlet (104) , and wherein the residues outlet of all the microreactors (20) are in fluid communication, and with a reactor residues outlet (106).

27. Reactor (100) for ammonia decomposition into hydrogen comprising several microreactors (20) as in claim 1, said first ammonia decomposition chamber (21) and said second heating chamber (22) are superposed to form a multi-layered structure in a coaxial and concentric tubular structure, wherein said microreactors (20) are associated in a way wherein considering a pair of associated microreactors (20), the second heating chamber (22) of one of the pair of microreactors (20) is superposed with the first ammonia decomposition chamber (21) of the other of the pair of microreactors (20), wherein the ammonia feeding inlet (102) of all the microreactors (20) are in fluid communication, and with a reactor (100) ammonia feeding inlet (102), wherein the air feeding inlet (108) of all the microreactors (20) are in fluid communication, and with a reactor air feeding inlet (108) , wherein the hydrogen outlet (104) of all the microreactors (20) are in fluid communication, and with a reactor hydrogen outlet (104) ,N EOLO-1 -PCTand wherein the residues outlet of all the microreactors (20) are in fluid communication, and with a reactor residues outlet (106).

28. System for generating energy with hydrogen, comprising a reactor (100) as defined in any of claims 25 to 27 providing hydrogen, wherein it further comprises:- an ammonia tank in fluid connection with the ammonia feeding inlet (102) of said reactor (100),- a first heat exchanger between said ammonia tank and the ammonia feeding inlet (102) of said reactor (100), being able to bring heat to ammonia flowing from said ammonia tank to the ammonia feeding inlet (102) of said reactor (100), said heat being provided by the gas flow coming from the reactor hydrogen outlet (104) .

29. System for generating energy with hydrogen provided by a reactor (100) as defined in claim 25 to 28, further comprising a hydrogen storage unit in fluid connection with the hydrogen H2 outlet of the first ammonia decomposition chamber (21).

30. System for generating energy as in claim 28 or 29, wherein it further comprises:- a second heat exchanger between said ammonia tank and the ammonia feeding inlet (102) of said reactor (100), being able to bring heat to ammonia flowing from said ammonia tank to the ammonia feeding inlet (102) of said reactor (100), said heat being provided by an external thermal energy source.

31. System for generating energy as in any of claims 28 to 30, wherein it further comprises:- a powertrain fuelled by the hydrogen generated by the reactor (100) and converting said hydrogen into kinetic energy or in electric energy.N EOLO-1 -PCT32. System for generating energy according to claim 31, wherein said powertrain comprises a hydrogen internal combustion engine converting said hydrogen into kinetic energy.

33. System for generating energy according to any of claims 28 to 30, wherein said powertrain comprises a hydrogen fuel cell converting said hydrogen into electric energy.

34. System for generating energy as in claim 33, wherein electricity generated by said fuel cell is supplied to at least one of the following devices: a motor, a drive unit, an electric battery of a mobile vehicle.

35. System for generating energy as in any of claims 28 to 34, wherein said reactor (100) is configured to be able to be mounted to a vehicle, including a terrestrial vehicle, such as a passenger vehicle or a heavy-duty truck, an aerial vehicle, an aquatic or maritime vehicle.

36. System for generating energy as in any of claims 28 to 35, comprises further either a hydrogen internal combustion engine converting said hydrogen into kinetic energy and a dynamo converting said kinetic energy into electric energy, or a hydrogen fuel cell converting said hydrogen into electric energy, wherein said electric energy powers any of the following : a motor, a drive unit, an electric battery, an electric battery of a mobile vehicle, a computer device, a telecommunication devices, a storage device.

37. System for generating energy with hydrogen, comprising a reactor (100) as defined in any of claims 26 to 36 providing hydrogen, wherein it further comprises: a H2 separation and purification unit (110) downstream of the reactor outlet (104).N EOLO-1 -PCT

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