DE202019102695U1 - membrane reformer - Google Patents

Abstract

Membrane reformer for producing hydrogen, comprising
a) a first cavity (1) with a catalyst and a feed (8) for a gaseous dehydrogenatable educt, in which the production of hydrogen and at least one further reaction product is carried out,
b) a second cavity (3) connected downstream of the first cavity, in which the production of hydrogen and at least one further reaction product is continued with simultaneous removal of the hydrogen produced via a membrane and introduction into a third cavity,
c) a third cavity (5) with a discharge (10) for hydrogen,
d) a membrane (4) made of a metallic material containing a metal or made of metal and placed flat over a porous or perforated film (7) or inserted between two porous or perforated films (7, 17) and inserted between the second and third cavity (5), each immediately adjacent to membrane or foil,
e) a process (9) for the hydrocarbon-containing gas, the at least one further reaction product and water vapor from the second cavity (3),
f) wherein the membrane reformer is formed by a plate stack with a plurality of individual plates on both sides of the at least one membrane and
g) wherein the cavities are formed by depressions or openings in at least one plate.

Description

The innovation relates to a membrane reformer, preferably a palladium membrane reformer according to the first protection claim.

Membrane reformers of the type mentioned in particular are used to produce hydrogen from hydrocarbon or alcohol-containing gas and water vapor or ammonia. In particular, small designs allow a decentralized use. Accordingly, preferred applications can be found in the supply of industrial customers in the capacity range below 500 Nm ³ / h, with membrane reformer units in a hydrogen supply from the natural gas network form a cheaper alternative to the use of bottle or cylinder bundles. They also provide an ideal source of hydrogen for H ₂ filling stations or fuel cell systems for mobile or stationary applications.

The hydrocarbons which can be used include both gaseous substances, for example methane and propane, but also substances converted into the vapor phase, such as (bio) ethanol or higher molecular weight substances (hexadecane) and also possible unsaturated or partially oxidized derivatives (alkenes, alcohols, acids, etc.). ).

Pure hydrogen is often needed at many chemical and other industrial sites in small quantities. So far, the production of methane (natural gas) is the cheapest. However, transport in gas cylinders or tank trucks is costly and unsustainable. Therefore, small compact units with high power density and low investment costs represent a very attractive solution. The fuel cell market is also looking for favorable options for hydrogen supply.

Other important business segments and worthwhile segments are the supply of hydrogen to industrial customers or hydrogen refueling stations. Since the transport of hydrogen is very expensive and the proportion of transported weight in hydrogen is very low, aggregates of up to 500 Nm ³ / h are worthwhile for generating hydrogen via membrane reformers. Here, the acquisition costs are relatively quickly earned, because natural gas brings little cost.

A goal of developments to the membrane reformer lies in a simplified and energy-efficient manufacturability of hydrogen from hydrocarbon-containing gas and water on the one hand and the reduction of components as well as the size for decentralized applications on the other hand.

EP 1 669 323 A1 discloses, by way of example, a microstructurable reactor and method for producing hydrogen from ethanol and water. The hydrogen is diverted through a membrane and thus separated from the remaining reaction products. The reactor is formed by a plate stack with individual plates.

Membrane reformers can also be used for accelerating dehydrogenation, the thermodynamic boundary condition being shifted with regard to greater conversion with removal of the hydrogen formed. These dehydrogenations include hydrogen storage applications based on liquid organic hydrogen carriers (known as LOHC for short). There is a particularly compact and dynamic mode of operation with high volume-specific hydrogen release rates or reaction rates desired to discharge, for example, the hydrogen in a short time in a pressure accumulator or feed directly into a fuel cell system.

EP 2 578 532 A1 discloses use of a combustion zone, a membrane-integrated reaction zone and a hydrogen exhaust zone. The sealing or connection technology takes place via screw connections.

US Pat. No. 7,922,781 B1 describes as the aforementioned EP 1 669 323 A1 also a device for the production of hydrogen with a combustion zone, a reaction zone with integrated membrane and a hydrogen extraction zone. Also, some procedural claims are set forth; For example, the system is to be heated by the catalytic combustion of stored hydrogen until the ignition point of the catalyst for other substances has been reached. The implementation of a multilayer system with regard to the distribution of substances is not discussed.

The disadvantages of the aforementioned systems are their handling, the complex interchangeability of modules and in the limited purity of the separated hydrogen. In particular, the systems often require the branches of the media, which are arranged perpendicular to the flow direction in the individual modules.

On this basis, an object of the innovation is to make a membrane reformer of the type mentioned for a simplified and energy-efficient production of pure hydrogen from hydrocarbon-containing gas and water safer and more efficient, the aforementioned disadvantages should be avoided.

The problem is solved by a membrane reformer having the features of claim 1. On this back related claims give advantageous embodiments again.

It proposes a membrane reformer for the production of hydrogen. This comprises a first cavity (pre-reforming zone, i.e. pre-reaction zone without membrane) with a catalyst and a feed of a gaseous dehydrogenatable starting material, preferably together with steam, in which the production of hydrogen and at least one further reaction product is carried out. This is followed by a second cavity connected downstream of the first cavity (preferably with one, more preferably the above-mentioned catalyst of the first cavity), in which the production of hydrogen and at least one further reaction product with simultaneous removal of the generated hydrogen via a membrane and introduction into a third Cavity continues, followed by a third cavity with a drain for hydrogen.

Preferably, the gaseous dehydrogenatable educt is or contains a hydrocarbon, more preferably an alcohol, preferably methanol, ethanol and / or ammonia, and more preferably contains water vapor.

The membrane is made of metallic material containing a metal or made of metal. It is placed flat over a porous or open-worked film or inserted between two porous or open-worked films. The membrane is located between the second and third cavities, each directly adjacent to the membrane or foil.

Furthermore, the membrane reformer comprises a drain for the hydrocarbon-containing gas, the at least one further reaction product and optionally water vapor from the second cavity.

The membrane reformer has a layered construction, i. it is formed by a plate stack with several individual plates (plates, films) on both sides of the at least one membrane. The cavities are formed by depressions or openings in each case at least one plate.

The membrane reformer is therefore particularly suitable for miniaturization, in which the plates preferably have a thickness of 10 to 2000 microns, more preferably from 20 to 1000 microns, more preferably between 30 and 200 microns. The lateral dimensions of the preferably rectangular or square individual plates of such a micromembrane reformer are preferably between 10 and 300 mm, more preferably between 20, 30 or 40 and 60, 80 or 100 mm.

Preferably, each transition in the plate stack between two plates or between a plate and a film or membrane or between a membrane and a film is formed by sealingly surrounding the cavities and / or inlet and outlet welds. The welds each connect two adjacent layers, i. Single plates, membranes and / or films together. A weld seam penetrates preferably only one transition and the two adjacent layers, while the respective subsequent layer is placed after the welding of the weld, with this another transition forms and is welded by another welding process with the adjacent layer. The circumferential weld advantageously forms a material transition between two layers and thus forms a sealing barrier in the transition. It is essential that the welds are offset between two transitions adjacent to the plate stack and not intersecting each other, i. do not touch each other.

The type of construction of the connection technique by laser or electron beam welding advantageously also allows distortion-free or low-tension design of the membrane reformer, which ultimately individual modules, each with a planar membrane surface can be built and arranged by a right angle to the zones media access via seals to a total package are stackable, ie can be exchanged individually in the event of a defect.

An embodiment of the membrane reformer is characterized by a first cavity filled with particles of a catalyst for the reaction of the dehydrogenatable starting material and / or a wall or wall coating consisting of the catalyst. In this way, the beginning of the reaction takes place already in the first cavity, without there being a separation of hydrogen. As a result, first of all a hydrogen partial pressure is generated in the direction of reaction. The conversion is sufficiently small so as not to induce equilibrium limitation of the reaction. The arrangement avoids any recirculation of hydrogen into the reaction mixture, which could occur if the entire reaction space were spanned by a hydrogen permeable membrane.

A further embodiment of the membrane reformer provides that the second cavity is filled with particles of a catalyst for the reaction of the dehydrogenatable educt and / or a wall or wall coating consists of the catalyst. The reaction is merely continued in the second cavity, whereas only in this case a membrane separation of hydrogen takes place in parallel. The hydrogen partial pressure in the gas phase is lowered by the separation, so that further no equilibrium limitation of the reaction takes place. This makes it possible to achieve higher conversions for the dehydrogenatable starting material.

The aforementioned catalyst for the reaction of the dehydrogenatable educt is or preferably contains platinum, palladium, nickel and / or copper. More preferably, the catalyst has an increased specific surface, which is accessible for reaction of the dehydrogenatable starting material. The provision of the large surface is preferably carried out in the form of a fissured surface topography or an open porosity or, for particles alternatively or additionally, a small particle size, preferably between 10 ¹ and 10 ⁴ nm particle size.

The membrane reformer is preferably further configured in such a way that the second and third cavities, which are respectively arranged on both sides via a membrane, span over a common membrane area over the membrane and the one or both foils in an overlapping manner. This ensures that a maximum effective area is available for the transport of hydrogen through the membrane.

The film or the two films around the membrane region furthermore preferably have a circumferential dense region which is neither perforated nor porous. This serves to ensure that a substance discharge, preferably formed by the hydrogen to be removed, is discharged exclusively via the membrane.

In an advantageous embodiment, an inlet for a purge gas is additionally provided in the third cavity. The use of purge gas lowers the hydrogen partial pressure in the third cavity. This increases the parameter space for the use of the device, since hydrogen can also be dissipated at relatively low hydrogen partial pressures. Expediently, the process for hydrogen is at the same time also a process for the purge gas. More preferably, a predominant volume fraction of the third cavity is arranged between drain and inlet.

Tempering means, preferably a channel system for a tempering fluid, are preferably provided for the cavities, in particular the first two cavities. In this way, the temperature and thus the reactions in the first cavity can advantageously be controlled or limited upwards and / or downwards. The preferred channel system further preferably comprises recess structures in at least one plate or foil for the passage of a Temperierungsfluids and further preferably have no fluidic connection to the aforementioned cavities including the supply, discharge and connecting lines.

Alternatively, the said temperature control means in a further possible embodiment comprise a catalytic combustion of the residual portions of the dehydrogenatable starting material contained in the second cavity, non-separated hydrogen and / or other combustible products on a suitable catalyst, wherein the catalyst in a channel system comprising well structures in at least one single plate of the plate stack is arranged for the passage of the outlet of the second cavity mixed with air.

A preferred embodiment of the membrane reformer provides for an embodiment of the inlets and outlets in such a way that the membrane reformers can be assembled and operated in parallel with further membrane reformers, preferably of the same type, to form a membrane reformer system. This embodiment provides inflows and outflows to and from the cavities that exit or exit into collection channels. The collecting channels preferably penetrate orthogonally the plates (foils) of the plate stack, wherein the plates in the transition to the respective adjacent plates not only over the cavities and / or inlet and outlet lines, but also through the collecting channels sealingly circumferential welds with the respective adjacent flaps or membranes are connected. It is essential here that the weld seams are offset between two adjacent transitions and are not arranged to intersect one another. In this case, the collection channels penetrate the entire plate stack orthogonally, in particular similar membrane reformers of the same dimensions can be stacked on top of one another, wherein the collection channels of the respective aligned lines are arranged side by side. One embodiment therefore provides that the collecting ducts penetrate the plate stack in a straight line and orthogonal to the plates.

Alternatively, it is advisable to uniformly arrange at least the arrangement of the outlets and inlets of the collecting channels, in particular in the respective final plates or foils.

A preferred embodiment also provides that at least one inlet and / or outlet from a cavity takes place from a first plate into a collecting channel through an opening in a second plate and furthermore through a groove-shaped depression in a third plate towards the collecting channel.

The membranes of the membrane reformer used are preferably between 1, 2 or 3 and 10, 20 or 40 microns thick. Preferably, in the aforementioned micromembrane reformer, the thicknesses are preferably between 1 and 10 μm.

The permeability of the membrane to hydrogen must be given, preferably this permeability of the membrane is selective for hydrogen. For this purpose, in particular a membrane of palladium or a palladium alloy are suitable. Alternatively, such a membrane contains palladium or a palladium alloy. More preferably, the membranes are made by a rolling or a sputtering process. An alternative preparation provides for the membrane to be built up on a porous (open-porous) or perforated film as carrier substrate (support plate), preferably vapor-deposited directly onto the film via a sputtering process or alternatively, chemically deposited. The porous or perforated film is made of a metal and is preferably between 30 and 200 microns thick.

The cavities in the plate stack are preferably arranged one above the other and each extend rectangularly in a plate, preferably as depressions or openings in the plates. Furthermore, the inlets and outlets are preferably slit-shaped and in each case spanned a predominant portion of one side of a rectangular cavity.

A particular advantage of the construction described and the aforementioned embodiments in the context of a plate stack with individual plates lies in the Miniaturizierbarkeit and in the interconnection of a variety of small and thus thermally well controllable membrane reformer to membrane reformer systems.

• 1 eine schematische Prinzipskizze eines Membranreformers,
• 2 prinzipielle Explosionsansichten mit der Darstellung aller Platten eines Plattenstapels einer Ausführungsform eines Membranreformers in zwei Perspektiven,
• 3 prinzipielle Explosionsansichten mit der Darstellung aller Platten eines Plattenstapels einer weiteren Ausführungsform eines Membranreformers in zwei Perspektiven,
• 4 eine perspektivische Ansicht einer Ausgestaltung einer durchbrochenen Folie als Trägersubstrat (Stützplatte) für die Membran sowie
• 5 eine Darstellung aus einer Umsetzung von Methan mit Wasserdampf Methanumsatz X_CH4 als Funktion der Wasserstoffrückgewinnungsrate φ_H2 für acht verschiedene Betriebspunkte.

The innovation will be explained in more detail with reference to exemplary embodiments, the following figures and descriptions. The illustrated features and their combinations are not limited to these embodiments and their embodiments. Rather, these are representative of other possible, but not explicitly illustrated as embodiments further embodiments combined. Show it

• 1 a schematic schematic diagram of a membrane reformer,
• 2 schematic exploded views showing all plates of a plate stack of an embodiment of a membrane reformer in two perspectives,
• 3 schematic exploded views showing all plates of a plate stack of another embodiment of a membrane reformer in two perspectives,
• 4 a perspective view of an embodiment of a perforated film as a carrier substrate (support plate) for the membrane and
• 5 a representation from a conversion of methane with water vapor methane conversion X _CH4 as a function of the hydrogen recovery rate φ _H2 for eight different operating points.

The principle basic structure of an exemplary membrane reactor and the guided in these streams show 1 in a schematic cross-sectional representation.

The membrane reformer essentially comprises a first cavity 1 as a pre-reforming stage, after a flow diversion 2 in a second cavity 3 as a reforming stage, a third cavity 5 and a hydrogen permeable membrane disposed between the second and third cavities 4 , The first and second cavities also have a catalyst layer away from the membrane 6 on the walls of the cavity. The membrane itself is between two perforated films 7 used as carrier substrates (support plates).

Through a feed 8th there is an introduction of a gaseous dehydrogenatable educt, in the example CH ₄ and H ₂ O, in the first cavity. There is carried out in the first cavity a pre-reforming, ie an incipient reaction of the starting material in hydrogen and a further reaction product under the action of the aforementioned catalyst. When the reaction is ongoing, the reaction mixture is forwarded via the flow deflection into the second cavity 3 and thus also to the membrane 4 in which the reaction continued, but at the same time the hydrogen forming through the membrane in the third cavity 5 is transferred. While a residual portion of hydrogen (H ₂ ), an unreacted residue of the starting material (CH ₄ , H ₂ O, ie hydrocarbon-containing gas) and the other reaction products (CO, CO ₂ ) via a drain 9 are discharged from the second cavity, a discharge of hydrogen (H ₂ ) takes place via an outlet 10 from the third cavity.

Further in 1 shown is a channel 11 in which a fuel (eg CH ₄ ) with oxygen (O ₂ ) is introduced, and there oxidized to form heat (in particular to CO ₂ and water) and is discharged to the right out of the channel. The resulting heat serves as a tempering agent for the membrane reformer, ie it is transmitted via the channel wall in particular to the vorgeannten cavities. A fluidic connection between the channel and one of the cavities preferably does not exist.

Preferred embodiments of the realized through a plate stack membrane reformer can be found in 2 and 3 as exploded views from diagonally above (left) and diagonally below (right). The particular in 2 Arrows on the left indicate the material flows in Membrane reformer again. The foils of the plate stack are preferably made of a corrosion resistant steel and preferably have the same outer dimensions, wherein the lateral extents and the arrangements of the first, second and third cavities on the respective foils are preferably the same.

2 represents an embodiment without Temperierungsmittel again while 3 this tempering has in separate additional films.

• - Die untere Abschlussfolie 12 ist ein dichtender Abschluss des Membranreformers nach unten. Er weist lediglich einen Zulauf 8 für ein gasförmiges dehydrierbares Edukt aus einem alle Folien durchdringenden ersten Sammelkanal 13 sowie einen Teil des Ablaufs 9 für ein Restanteil von Wasserstoff, ein nicht umgesetzter Rest des Edukts sowie die weiteren Reaktionsprodukte in einen alle Folien durchdringenden zweiten Sammelkanal 14 auf. Ab- und Zulauf sind auf der unteren Abschlussfolie als rillenförmige Vertiefungen dargestellt. Ferner durchdringen je ein ebenfalls alle Folien durchdringender Auslass 10 für Wasserstoff aus der dritten Kavität sowie ein Spülgaskanal 20 für die Zuleitung eines Spülgases in die dritte Kavität die untere Abschlussfolie.
• - Die Vorreformierungsfolie 15 weist als vorzugsweise rechteckige flächige Vertiefung die erste Kavität auf, in die vorzugsweise über die eine gesamte Stirnseite der vorgenannte Zulauf ausmündet. Die Wandungen der Kavität sind vorzugsweise mit einem Katalysator der vorgenannten Art beschichtet. In der dem Zulauf gegenüberliegenden Stirnseite mündet die erste Kavität in die Strömungsumlenkung aus, womit in der Kavität eine möglichst gleichförmiger Strömungsquerschnitt realisierbar ist.
• - Es folgt die Reformierungsfolie 16 mit der zweiten Kavität, ebenfalls mit Wandungen, die mit Katalysator beschichtet sind. Ebenfalls wird das Reaktionsgemisch wie in der ersten Kavität über eine Stirnseite aus der Strömungsumlenkung eingeleitet und über die gegenüberliegenden Stirnseite über den Ablauf 9 ausgeleitet, womit sich auch hier ein möglichst gleichförmiger Strömungsquerschnitt ausbildet.
• - Die Reformierungsfolie ist mit einer vorzugsweise nur im Erstreckungsbereich der zweiten Kavität durchbrochenen Folien 7 als Trägersubstrate (Stützplatten) für die Membran abgedeckt. Auf der durchbrochenen Folie liegt die Membran 4 auf, die sich vorzugsweise - wie dargestellt - nur über die die zweite und dritte Kavität und nicht über die vorgenannten Sammelkanäle erstreckt. Vorzugsweise ist die Membran - wie ebenfalls dargestellt - zwischen der vorgenannten durchbrochenen Folie 7 und einer zweiten durchbrochenen Folie 17 angeordnet.
• - Es folgt die Wasserstoffabfuhrfolie 18 mit der als Vertiefung ausgearbeiteten und zur zweiten durchbrochenen Folie 17 hin weisenden dritten Kavität 5, wobei jene zur Membran hin den gleichen Erstreckungsbereich wie die zweite Kavität überspannt.
• - Die folgende Umlenkfolie 19 und die obere Abschlussfolie 21 dienen insbesondere der Umlenkung des Spülgases aus dem Spülgaskanal 20 in die Dritte Kavität sowie der Umlenkung des Spülgases mit dem durch die Membran abgetrennten Wasserstoff aus der dritten Kavität in den Auslass 10. Die Umlenkfolie 19 ermöglicht in vorteilhafter Weise die vorzugsweise vorgeschlagene Verbindung der Folien untereinander, wobei jeder Übergang im Plattenstapel zwischen zwei Platten oder zwischen einer Platte und einer Folie oder Membran oder zwischen einer Membran und einer Folie durch um die Kavitäten und/oder Zu- und Ableitungen dichtend umlaufenden Schweißnähte gebildet ist sowie die Schweißnähte zwischen zwei im Plattenstapel benachbarten Übergängen versetzt und nicht kreuzend zueinander angeordnet sind. Die Umlenkungen selbst sind im Wesentlichen als Vertiefungen auf der Unterseite der oberen Abschlussfolie dargestellt. Vorzugsweise sind die Öffnungen von unterer und oberer Abschlussfolie deckungsgleich, sodass eine Parallelschaltung mehrerer Membranreformer über eine Anordung derer übereinander realisierbar ist. 3 zeigt zudem noch drei weitere Folien, die die Temperierungsmittel für den Membranreformer umfassen. Im Gegensatz zu 1 sind diese hier nicht unmittelbar benachbart zur Vorreformierungsstufe (ersten Kavität 1), sondern über der oberen Abschlussfolie 21 d.h. angrenzend zur dritten Kavität 5 angeordnet.
• - Über der oberen Abschlussfolie 21 ist eine Brennkammerfolie 22 angeordnet, in der eine Brennkammer 23 als Vertiefung eingearbeitet ist. Die laterale Erstreckung der bevorzugt quaderförmigen Brennkammer auf der Brennkammerfolie entspricht vorzugsweise der der vorgenannten Kavitäten. Ferner ist ein bevorzugt über eine gesamte Stirnfläche der Brennkammer einmündender Brenngaszulauf 24 für ein bevorzugt gasförmiges Brenngas sowie ein bevorzugt auf der gegenüberliegenden Stirnfläche der Brennkammer ausmündender Abgasablauf 25 vorgesehen, wobei Brenngaszulauf und Abgasablauf jeweils fluidisch, vorzugsweise als rillenförmige Vertiefungen ausgestaltet, an je einen Brenngassammelkanal 26 bzw. Abgassammelkanal 27 angebunden sind. Brenngassammelkanal und Abgassammelkanal durchdringen vorzugsweise, wie zuvor für die Sammelkanäle für Edukte und Reaktionsprodukte beschrieben, alle Folien des Plattenstapels, vorzugsweise orthogonal zu den Folien.
• - Auf die Brennkammerfolie 22 ist eine Luftverteilerfolie 28 mit einem als Vertiefung oben eingebrachten Verteilervolumen 29 angeordnet. Die unten plane Luftverteilerfolie schließt vorzugsweise die die Brennkammer 23 bildende Vertiefung nach oben hin ab. Die Erstreckung des Verteilervolumens entspricht der der darunter angeordneten Brennkammer. Luftdurchführungen 30 vom Verteilervolumen zur Brennkammer, die über die gesamte Erstreckung vorgesehen sind, ermöglichen eine Luftzufuhr über das gesamte Brennkammervolumen und damit eine flächige Verbrennung in der Brennkammer. Das Verteilervolumen ist fluidisch (rillenförmige Vertiefung) an einen Luftsammelkanal 31 angeschlossen, der wiederum bevorzugt alle Folien des Plattenstapels durchdringt, vorzugsweise orthogonal zu den Folien.
• - Über der Luftverteilerfolie 28 ist eine obere Temperierungsmittelabdeckfolie 32 vorgesehen, die im Beispiel das Verteilervolumen nach oben hin begrenzt.

A description of the individual foils (individual plates) of the plate stack follows below, starting with the lowest foil:

• - The lower end foil 12 is a sealing end of the membrane reformer down. He only has an inlet 8th for a gaseous dehydrogenatable starting material from a first collection channel penetrating all the films 13 and part of the process 9 for a residual portion of hydrogen, an unreacted residue of the educt and the further reaction products in a foil all penetrating second collection channel 14 on. Drain and inlet are shown on the lower cover sheet as groove-shaped recesses. Furthermore penetrate a likewise all films penetrating outlet 10 for hydrogen from the third cavity and a purge gas channel 20 for the supply of a purge gas in the third cavity, the lower end foil.
• - The pre-reforming film 15 has as a preferably rectangular area depression on the first cavity into which opens preferably via the one entire end face of the aforementioned inlet. The walls of the cavity are preferably coated with a catalyst of the aforementioned type. In the opposite end of the inlet, the first cavity opens into the flow deflection, whereby in the cavity as uniform as possible flow cross-section can be realized.
• - It follows the reforming film 16 with the second cavity, also with walls coated with catalyst. Likewise in the first cavity, the reaction mixture is introduced via an end face out of the flow deflection and via the opposite end face via the outlet 9 discharged, which also forms a uniform as possible flow cross-section.
• - The reforming film is preferably with a perforated only in the extension region of the second cavity foils 7 covered as carrier substrates (support plates) for the membrane. The membrane lies on the perforated foil 4 on, which preferably - as shown - only on the second and third cavity and not over the aforementioned collection channels extends. Preferably, as also shown, the membrane is between the aforementioned perforated film 7 and a second open-worked film 17 arranged.
• - The hydrogen removal foil follows 18 with the developed as a recess and the second open-worked film 17 pointing third cavity 5 , wherein the spans to the membrane over the same extent range as the second cavity.
• - The following deflecting foil 19 and the top cover 21 serve in particular the deflection of the purge gas from the purge gas channel 20 into the third cavity and the deflection of the purge gas with the hydrogen separated by the membrane from the third cavity in the outlet 10 , The deflecting foil 19 Advantageously, the preferably proposed compound of the films with each other, wherein each transition in the plate stack between two plates or between a plate and a film or membrane or between a membrane and a film by sealing around the cavities and / or inlet and outlet welds is formed and the welds offset between two adjacent in the plate stack transitions and are not arranged crossing each other. The deflections themselves are shown essentially as depressions on the underside of the upper end foil. Preferably, the openings of the lower and upper end foil are congruent, so that a parallel connection of a plurality of membrane reformers via an arrangement of which one above the other can be realized. 3 also shows three more slides that include the temperature control agent for the membrane reformer. In contrast to 1 these are not immediately adjacent to the pre-reforming stage (first cavity 1 ), but over the top cover 21 ie adjacent to the third cavity 5 arranged.
• - Over the top cover 21 is a combustion chamber foil 22 arranged in a combustion chamber 23 is incorporated as a recess. The lateral extent of the preferably cuboid combustion chamber on the combustion chamber film preferably corresponds to that of the aforementioned cavities. Furthermore, a fuel gas inlet which preferably opens over an entire end face of the combustion chamber is provided 24 for a preferably gaseous fuel gas and a preferably on the opposite end face of the combustion chamber ausmündender exhaust gas outlet 25 provided, wherein fuel gas inlet and exhaust gas outlet each fluidly, preferably designed as groove-shaped depressions, depending on a fuel gas collection channel 26 or exhaust gas collection channel 27 are connected. Brenngassammelkanal and exhaust gas collection channel preferably penetrate, as described above for the collection channels for reactants and reaction products, all the films of the plate stack, preferably orthogonal to the films.
• - On the combustion chamber foil 22 is an air distribution foil 28 with a distribution chamber introduced as a recess at the top 29 arranged. The bottom plane air distribution foil preferably closes the combustion chamber 23 forming depression from above. The extension of the distribution volume corresponds to that of the combustion chamber arranged below. Bushings 30 From the distribution volume to the combustion chamber, which are provided over the entire extent, allow an air supply over the entire combustion chamber volume and thus a surface combustion in the combustion chamber. The distribution volume is fluidic (groove-shaped depression) to an air collection channel 31 connected, which in turn preferably penetrates all the films of the plate stack, preferably orthogonal to the films.
• - Above the air distribution foil 28 is an upper tempering agent masking film 32 provided, which limits the distribution volume in the example in the example.

In 2 and 3 are also on the slides various welding lines 33 represented, which are preferably formed by laser welding. The welding lines indicate the lines that are preferably approached by the laser beam of the welding system. The welds along the weld lines preferably connect the transition of two foils, in the illustrated embodiments, the respective foil with the respectively adjacent foil disposed thereunder (more preferably excluding perforated foils 7 and 17 and the membrane). Each transition in the plate stack between two plates or between a plate and a foil or membrane or between a membrane and a foil around the cavities and / or inlets and outlets is sealed to the outside of one of the circumferential weld. What is essential in such a preferred embodiment of the joining technique is that the welding lines of two adjacent transitions do not intersect, overlap or overlap in any other way. Consequently, the welds between two adjacent in the plate stack transitions are offset and not crossing each other.

Inside the membrane reactor, the circumferential weld lines are used to create a seal from the inside to the outside and between the individual foils. The welding is preferably carried out with a laser beam perpendicular to the individual foils.

In particular, a separation of the weld lines is avoided. In superimposed plates having a passage or circumferential sealing groove, also an alternating sequence of smaller and larger radii of the circumferential groove (with otherwise the same groove size) is realized so that the seam root does not hit the groove of the underlying weld and a reliable seal and compressive strength is guaranteed.

In addition, the welding of the array of plates from the central plate to the membrane is preferably done alternately from both sides to minimize distortion and to provide plane parallelism to the foils in the plate stack.

• - Verbindung des Übergangs zwischen Vorreformierungsfolie 15 und Reformierungsfolie 16,
• - anschließende Durchschweißung von Wasserstoffabfuhrfolie 18 durch die darunterliegenden Folien bis auf die Reformierungsfolie 16 (d.h. Verschweißung mehrerer Übergänge zugleich);
• - danach Anbindung der unteren Abschlussfolie 12 von unten;
• - abschließend erst Anbindung der Umlenkfolie 19 und dann der oberen Abschlussfolie 21.

A preferred welding order for a in 2 illustrated embodiment of the membrane reformer is:

• - Connecting the transition between Vorreformierungsfolie 15 and reforming film 16 .
• - subsequent penetration of hydrogen evacuation film 18 through the underlying films except for the reforming film 16 (ie welding multiple transitions at the same time);
• - Then connect the lower end foil 12 from underneath;
• - finally only connection of the deflecting foil 19 and then the top cover 21 ,

For an addition of the foils a in 3 shown embodiment is first referenced preferably to the above order, followed by a film-like preparation and welding of the films for a temperature (combustion chamber film 22 , Air distribution foil 28 and Temperierungsmittelabdeckfolie 32 ), whereby here only one transition at a time are welded together.

A central element of the design concerns the deflecting foil 19 , which allows a common connection to the hydrogen exhaust (channel 10 ) and to the purge gas channel 20 to produce on the films, without a passage of the purge gas from the purge gas channel to the channel away from the third cavity 5 on the bottom of the hydrogen removal foil 18 can take place.

Further advantages are found in the flow of the first and second wells. For example, a pre-reforming in the pre-reforming film allows 15 the buildup of a hydrogen partial pressure by reaction before contact with the membrane. The flow deflection 2 between the first and second cavity in turn provides a flow resistance between. This promotes on the one hand a uniform over the face surface inflow into the second cavity and on the other hand hinders a backflow of fluid components from the second cavity back into the first cavity.

The membrane 4 is on both sides of a perforated film 7 and 17 (preferably 50 microns thick and provided with 70 micron breakthroughs) framed for stabilization. The outer dimensions of the perforated films preferably correspond to those of the other films of the membrane reformer. More preferably, the apertures extend laterally onto the membrane and / or only in the region of the second and third cavities, while the remaining region has no openings.

Preferably, a non-porous edge of an open-pore membrane support (foil 7 and 17 ) ensures the sealing of the membrane to the outside. The Pd-containing membrane film preferably made of Pd or PdAg) is preferably only 3 to 20 microns thick (rolled or sputtered). One embodiment provides, the membrane directly on at least one of the open-pore foils 7 or 17 first a ceramic porous layer as a diffusion barrier for metal atoms in the palladium; then deposition of Pd or its alloys in various ways, for example. Sputtering, electroless deposition, electrochemical, or via a suspension plasma spraying.

An alternative embodiment of the films 7 and 17 For the membrane allows a laser sintering process, with a dense edge 34 is brought into the form of the reactor shown above ( 4 ). Essential in this embodiment is that the laser sintering in the inner open-pore area 35 a structure of additional groove-shaped channels 36 allows, which are used at the same time as hydrogen discharge channels, ie as part of the third cavity. A coating with membrane material or placing a membrane is then possible both on the top and the bottom of the film shown, with which the reformer is additionally made even more compact. It is important that the channels are also over the porous area 35 and the welding line 33 out in the dense border 34 continue and in a slot 37 etc. so that the separated hydrogen of the various modules can be collected.

5 shows test results from a conversion of methane with water vapor (methane conversion rate X _CH4 [%]) as a function of the H ₂ recovery rate φ _H2 [%] for eight different operating points. The lines represent calculated equilibrium conditions. Experimental values at pressures of 6, 8, 10, and 12 bar (from left to right) at 773 K (black filled symbols) and 823 K (white filled symbols), a constant W / F ratio of 0.33 g _cat h / mol _CH4 and an S / C ratio of 3. S / C indicates the molar ratio of steam to carbon (in methane). W / F is the ratio of catalyst mass to molten methane.

LIST OF REFERENCE NUMBERS

1

first cavity

2

flow deflection

3

second cavity

4

membrane

5

third cavity

6

catalyst layer

7

openwork foil

8th

Intake

9

procedure

10

outlet

11

channel

12

final film

13

first collection channel for educts

14

second collection channel for reaction products

15

Vorreformierungsfolie

16

reforming foil

17

second openwork foil

18

Hydrogen discharge film

19

Umlenkfolie

20

purge gas

21

final film

22

combustion chamber slide

23

combustion chamber

24

Fuel gas supply

25

exhaust gas flow

26

Fuel gas collection channel

27

Exhaust gas collection channel

28

Air distributor foil

29

distribution volume

30

Bushings

31

Air collection channel

32

Temperierungsmittelabdeckfolie

33

welding lines

34

dense border

35

open-pored area

36

grooved channels

37

Long hole

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• EP 1669323 A1 [0007, 0010]
• EP 2578532 A1 [0009]
• US 7922781 B1 [0010]

Claims (27)

Membrane reformer for producing hydrogen, comprising a) a first cavity (1) with a catalyst and a feed (8) for a gaseous dehydrogenatable educt, in which the production of hydrogen and at least one further reaction product is carried out, b) a second cavity (3) connected downstream of the first cavity, in which the production of hydrogen and at least one further reaction product is continued with simultaneous removal of the hydrogen produced via a membrane and introduction into a third cavity, c) a third cavity (5) with a discharge (10) for hydrogen, d) a membrane (4) made of a metallic material containing a metal or made of metal and placed flat over a porous or perforated film (7) or inserted between two porous or perforated films (7, 17) and inserted between the second and third cavity (5), each immediately adjacent to membrane or foil, e) a process (9) for the hydrocarbon-containing gas, the at least one further reaction product and water vapor from the second cavity (3), f) wherein the membrane reformer is formed by a plate stack with a plurality of individual plates on both sides of the at least one membrane and g) wherein the cavities are formed by depressions or openings in at least one plate. Membrane reformer after Claim 1 , characterized in that a) each transition in the plate stack between two plates or between a plate and a film or membrane or between a membrane and a film by around the cavities and / or inlet and outlet lines sealingly surrounding welds is formed and b) the Welded seams between two in the plate stack adjacent transitions offset and not crossing each other. Membrane reformer after Claim 1 or 2 , characterized in that the gaseous dehydrogenatable educt contains water vapor. Membrane reformer according to one of the preceding claims, characterized in that the dehydrogenatable educt is or comprises a hydrocarbon. Membrane reformer according to one of the preceding claims, characterized in that the dehydrogenatable educt is or comprises an alcohol, preferably methanol or ethanol. Membrane reformer according to one of the preceding claims, characterized in that the dehydrogenatable educt is or comprises ammonia. Membrane reformer according to one of the preceding claims, characterized in that the first cavity is filled with particles of the catalyst for the reaction of the dehydrogenatable reactant and / or a wall or wall coating consist of the catalyst. Membrane reformer according to one of the preceding claims, characterized in that the second cavity is filled with particles of a catalyst for the reaction of the dehydrogenatable reactant and / or consist of a wall or wall coating of the catalyst. Membrane reformer according to one of the preceding claims, characterized in that the catalyst for the reaction of the dehydrogenatable educt contains platinum, palladium, nickel and / or copper. Membrane reformer according to one of the preceding claims, characterized in that the respectively arranged on both sides via a membrane second and third cavities spanning a common membrane area over the membrane and the one film or the two films overlap same. Membrane reformer according to one of the preceding claims, characterized in that the one film or the two films around the membrane region have a circumferential dense region which is neither perforated nor porous. Membrane reformer according to one of the preceding claims, characterized in that an inlet for a purge gas is additionally provided in the third cavity and the sequence for hydrogen is at the same time also an outlet for the purge gas. Membrane reformer after Claim 12 , characterized in that between outlet and inlet a predominant volume fraction of the third cavity is arranged. Membrane reformer according to one of the preceding claims, characterized in that tempering means are provided for the first cavity. Membrane reformer after Claim 14 , characterized in that the tempering means is formed by a channel system comprising recessed structures in at least one plate for the passage of a Temperierungsfluids. Membrane reformer after Claim 14 characterized in that the tempering means comprise a catalytic combustion of the residual portions of the dehydrogenatable starting material contained in the second cavity, non-separated hydrogen and / or other combustible products on a suitable catalyst, wherein the catalyst in a channel system comprising well structures in at least one Single plate of the plate stack is arranged for the passage of the outlet of the second cavity mixed with air. Membrane reformer according to one of the preceding claims, characterized in that a) the inlets and outlets to or from the cavities in collecting channels or open, b) the collecting channels penetrate the plates of the plate stack and c) the plates in transition to the respective adjacent plates not only connected to the respective adjacent flaps or membranes around the cavities and / or inlet and outlet lines, but also through the collecting ducts sealingly surrounding welds, d) wherein the welds between two adjacent junctions offset and not crossing each other , Membrane reformer after Claim 17 , characterized in that at least one inlet and / or outlet from a cavity of a first plate in a collecting channel by a breakthrough of a second plate and further by a groove-shaped recess in a third plate to the collecting channel out. Membrane reformer after Claim 17 or 18 , characterized in that the collecting ducts penetrate the plate stack in a straight line and orthogonal to the plates. Membrane reformer according to one of the preceding claims, characterized in that the membrane is between 3 and 20μm thick. Membrane reformer according to one of the preceding claims, characterized in that the permeability of the membrane for hydrogen is selective. Membrane reformer after Claim 21 , characterized in that the membrane consists of palladium or a palladium alloy or contains palladium or a palladium alloy. Membrane reformer after Claim 21 or 22 , characterized in that the membrane is made by a rolling or a sputtering process. Membrane reformer according to one of Claims 21 to 23 , characterized in that one of the films is porous and the membrane is sputtered on a sputtering process directly on the film or chemically deposited. Membrane reformer according to one of the preceding claims, characterized in that the one or two porous or perforated films are made of a metal and are between 30 and 200μm thick. Membrane reformer according to one of the preceding claims, characterized in that the cavities are arranged one above the other in the plate stack, each extending rectangularly in a plate and the inlets and outlets are slot-shaped and each span a major portion of one side of a rectangular cavity. Membrane reformer system comprising a plate stack with at least two stacked in the plate stack membrane reformer according to one of the preceding claims.

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