WO2002085777A2

WO2002085777A2 - Device for producing and/or preparing a fuel for a fuel cell

Info

Publication number: WO2002085777A2
Application number: PCT/EP2002/004411
Authority: WO
Inventors: Peter Prechtl; Markus HÖHN; Sven Theisen; Armin Bartsch; Günter HAUSINGER
Original assignee: Peter Prechtl; Hoehn Markus; Sven Theisen; Armin Bartsch; Hausinger Guenter
Priority date: 2001-04-21
Filing date: 2002-04-22
Publication date: 2002-10-31
Also published as: AU2002319143A1; EP1383599A2; WO2002085777A3; DE10217335A1

Abstract

The aim of the invention is to provide a device (10) for producing and/or preparing a fuel for a fuel cell, which comprises a number of individual components and which requires little space and has a simple constructive design. To this end, the device (10) is configured as a sequence of individual layers (11, 12), comprising at least one first layer (11) for guiding therethrough a process medium that has at least partially a channel structure with at least one channel (16, 17), and at least one second layer (12) that has at least one component for treating the process medium flowing across the at least one first layer (11). The device (10) is further designed as a single microstructure component wherein all individual components are integrated into one single component.

Description

description

Device for generating and / or processing a fuel for a fuel cell

The present invention relates to a device for producing and / or processing a fuel for a fuel cell, which has a number of individual components.

Fuel cells have been known for a long time and are becoming increasingly important in the automotive industry, for example. Of course, other possible uses for fuel cells are also conceivable. Examples include fuel cells for mobile devices such as computers or the like, right up to power plants. Here, fuel cell technology is particularly suitable for the decentralized energy supply of houses, industrial plants or the like.

In a fuel cell, for example a PEM fuel cell, electricity is generated by a chemical reaction. A fuel such as hydrogen and an oxidizing agent such as oxygen from the air are converted into electrical energy and a reaction product such as water. A fuel cell essentially consists of an anode part, a membrane and a cathode part. The membrane consists of a gas-tight and proton-conducting material and is arranged between the anode and the cathode in order to exchange ions. The fuel is supplied on the anode side, while the oxidant is supplied on the cathode side. Protons or hydrogen ions are generated at the anode by catalytic reactions and move through the membrane to the cathode. At the cathode, the hydrogen ions react with the oxygen and water is formed. The electrons released during the reaction can be conducted as electrical current through a consumer, for example the electric motor of an automobile. If one wants to operate the fuel cell with a readily available or storable fuel, such as natural gas, methanol, gasoline or the like, the hydrocarbon must first be converted into a hydrogen-rich gas in an arrangement for producing and / or processing a fuel. This essentially decomposes to hydrogen and carbon dioxide.

Furthermore, carbon monoxide is also produced, which is a gas which is harmful to the fuel cell, since it renders the catalyst on the anode side ineffective and must therefore be removed before the fuel enters the fuel cell. From a certain concentration, the carbon monoxide in the fuel cell can result in the power output by the fuel cell being reduced and consequently in the efficiency of the fuel cell being greatly reduced.

The arrangement for producing and / or processing fuel generally consists of a number of individual components, which can be, for example, chemical reactors such as reformers, shift reactors, reactors for selective oxidation, evaporators, heat exchangers and the like.

In some of the components mentioned, which in turn can consist of a number of individual elements, exothermic reactions take place, which means that heat is released. This heat must be dissipated, which can be done for example via a heat exchanger. In other components, the medium must have a certain reaction temperature, for example, which can also be achieved by using heat exchangers. There are also components that require heat. One of these reactor elements is, for example, the evaporator. Heat must be supplied to the evaporator for operation. This is done, for example, using an appropriate heating element.

In the reformer, a starting material is reformed, for example, into a hydrogen-rich gas. The reformer is used, for example, to make one from a hydrocarbon serving as a starting material, for example gasoline To produce fuel for the fuel cell. Depending on the design of the reformer, it may be necessary to supply heat to the reformer for operation, which can be done using appropriately designed heating elements.

If the content of harmful components for the fuel cell, such as carbon monoxide, in the fuel is still too high after leaving the reformer, these can be reduced in a downstream shift reactor, for example by a homogeneous water gas reaction, and then in a reactor selective oxidation, for example for the selective oxidation of carbon monoxide to carbon dioxide. This reduces the CO content to values that are tolerable for the fuel cell.

So far, it has been common for the individual components of the device for producing and / or processing fuel to be present as separate components. The individual components are first manufactured independently of one another and then combined to form the overall system. On the one hand, this is space-intensive and, on the other hand, it is structurally complex, since the individual components have to be connected to one another, which is usually done via corresponding line systems. These systems have many connecting elements, which entail increased assembly and manufacturing costs. The systems work under overpressure and sometimes very high temperatures. These elements represent potential leakage points. The costs for these systems are correspondingly high.

In particular for mobile applications, however, the downsizing of the established technologies from large-scale production is necessary. In addition, the costs and the cost of materials have to be reduced.

So far, for example, reactors exist which are filled with a catalyst based on bulk material (pellets). Reactors are also known in which the catalyst is applied to monoliths (cf. exhaust gas catalyst in a motor vehicle). When a process medium flows through such a reactor, there is a reaction between the process medium and the catalyst material. Such reactions are often exothermic. Such reactors have the disadvantage that no integration of heat management is possible.

This should be illustrated using the example of a chemical reactor for selective oxidation of carbon monoxide in carbon dioxide. This is a highly exothermic reaction (conversion of CO + 02 into CO2). Today's reactors for selective oxidation consist of a number of individual components.

First of all, a heat exchanger is required to cool the process medium. A mixing unit is also required in order to be able to meter air into the process medium. In addition, a mixing section is required for homogeneous mixing of the very small volume of air. Of course, the actual chemical reactor is also required, which is usually designed without its own cooling. Finally, at least one further heat exchanger is required to cool the process medium upstream of the fuel cell. If necessary, the above-described required individual components of the device for generating and / or processing the fuel can form a system, with several such systems being able to be connected in series, depending on the embodiment.

The individual components of the device are initially available as components which are independent of one another and which, with the disadvantages described above, then have to be combined to form an overall system via corresponding line systems.

The present invention has for its object to provide a device for generating and / or processing a fuel for a fuel cell, with which the disadvantages described can be avoided. In particular, a device is to be provided which can be manufactured compactly and with little space requirement and which at the same time is particularly powerful. Furthermore, an advantageous use of such a device is to be specified.

This object is achieved according to the invention by the device with the features according to independent claim 1 and the use according to claim 20. Further advantages, features, details, aspects and effects of the invention result from the subclaims, the description and the drawing. Features and details that are described in the context of the device according to the invention naturally also apply in connection with the use according to the invention, and vice versa.

The invention is based on the basic idea that a device for producing and / or processing fuel for a fuel cell, which has a number of individual components, is designed as a layer sequence of individual layers with a channel structure, the device being designed as a single component in microstructure technology and whereby all individual components are integrated in the one, single component.

According to the present invention, a device for generating and / or preparing a fuel for a fuel cell is provided, which has a number of individual components. The device according to the invention is characterized in that the device is designed as a layer sequence of individual layers, with at least one first layer for passing a process medium through it, which at least in some areas has a channel structure with at least one channel, and with at least one second layer that has at least one component for Treatment of the process medium flowing through the at least one first layer has that the device is designed as a single component in microstructure technology and that all individual components are integrated in the one, single component. The term microstructure technology is usually understood to mean structures which are in the size range in the range of less than one millimeter (1 μm to 1000 μm). In the present application, the sizes of the structures are not limited to these dimensions. For example, structures on the order of one may be required Represent zenith meter. The systems are preferably particularly efficient today if the structures are in the order of magnitude between 100 μm and 1000 μm. It is important that a dimension of the duct dimension is already decisive for performance (eg duct height). The channels have dimensions such as

Channel width: 0.2 mm to 5 mm (or several centimeters)

Channel height: 0.1 mm to 1 mm (or more),

Width or thickness of the channel walls: 50 µm to 500 µm (or also in the range of

millimeters)

Length of the channels: 1 mm to a few cm (10 cm, 20 cm)

Most of the time, the microstructures are built up by stacking the same or different layers on top of each other and connecting them using a suitable joining process (e.g. soldering, welding, gluing, clamping, ...). The structures are created by various methods. Examples are: etching, embossing, turning, milling, extruding, injection molding, forming, etc.

The device according to the invention is initially very powerful. Furthermore, the device requires only a small amount of space, so that it can be made very compact. The device can therefore advantageously be used wherever only a small amount of space is available.

A basic idea of the invention is that the device is designed as a layer sequence of individual layers. This has a number of advantages. It is thus possible in a simple and inexpensive manner to initially produce the individual layers of the device separately and then to join them to form the final device. Furthermore, the number and / or arrangement and / or sequence of the individual layers can also be varied, so that the device can be easily adapted to the prevailing requirements. The layered design of the device also ensures that good heat transfer between the individual layers can be achieved. The layer sequence initially consists of at least a first layer for passing the process medium through. Of course, more than one first layer can also be provided per device. The first layer has, at least in regions, a channel structure with at least one channel. Some non-exclusive examples of what such a first layer could look like are presented in the further course of the description.

Furthermore, the layer sequence consists of at least one second layer, which has at least one component for treating the medium flowing through the at least one first layer. Here too, of course, several second layers can also be provided for each device. Non-exclusive examples of possible second layers are explained in more detail below.

In the light of the present invention, treatment is understood to mean any type of action on the process medium. Treatment can mean, for example, that the process medium changes, for example as a result of a chemical reaction, for example a catalytic reaction. However, treatment can also mean that the physical state or the external state of the process medium changes without changing its chemical composition. Treatment can therefore also mean that the process medium is merely heated or cooled, that it is evaporated or the like. The invention is not limited to certain forms of treatment. Rather, these result from the respective field of application of the device. The treatment of the process medium therefore includes any direct or indirect, external or internal influence on the process medium.

The first and second layers are combined to form a layer sequence or a layer stack. The sequence pattern of the individual layers can be designed as desired. For example, it can be provided that a first and a second layer are always stacked on top of one another. Of course, several first and / or second layers can also be stacked directly on top of one another, then after several first and / or second layers each follow one or more layers of the other type. Irregular sequence patterns of the individual layers can thus also be implemented, so that the design of the device can be adapted precisely to the prevailing requirements.

According to the invention, the device is designed as a single component in microstructure technology. In particular, it is provided that the at least one channel of the at least one first layer is designed as a microchannel. Of course, the further channels of the device described below can also be designed as microchannels. The design in microstructure technology ensures that a large number of microchannels can be realized in the smallest space, the width and height of which are in the submillimeter range. For this reason, such devices have high specific surfaces, that is to say a high ratio of channel surface to channel volume. Furthermore, appropriately designed devices, which in this case are referred to as microreactors - as the name suggests - have a very high performance with only a small space requirement.

All individual components of the device are now integrated in the one, single component. This has the advantage that the previously required line systems and connection systems between the individual components can be dispensed with. This considerably simplifies the construction of the device. Furthermore, enormous space savings can be achieved.

The advantage of the invention is therefore that the device is designed as a single component in microstructure technology. The individual components are now integrated in the device, for example the connection technology (cooling water to and from the fuel cell), heat exchanger, mixing section, cooled chemical reactor and the like. So there is only a single component that takes up little space.

According to the present invention, those individual components of the device, which were previously separate, are provided by corresponding line systems connected, individual components were formed within the device in the first and second layers. Some non-exclusive examples of how this can be done are described below.

The at least one first layer and the at least one second layer can advantageously be thermally coupled to one another at least in regions. This means that the layers do not necessarily have to be directly connected to one another. In the light of the present invention, thermally coupled only means that heat exchange in the area of the thermal coupling should be possible. If the individual layers are stacked on top of one another as a layer sequence of individual layers, the thermal coupling advantageously comes about in that the individual layers are placed directly on top of one another. The heat exchange can then take place over the respective layer surfaces. This makes it possible in a simple manner that the heat generated in one layer can be easily transferred to or into another layer.

The at least one first layer can advantageously have at least one reaction passage, at least one reaction channel being formed in the reaction passage. The reaction passage can act as the actual chemical reactor, for example.

In a further embodiment, the at least one first layer can have at least one cooling / heating passage, at least one cooling / heating channel being formed in the cooling / heating passage and wherein the cooling / heating passage seen before and in the flow direction of the process medium / or is provided after the reaction passage. The process medium can, for example, be brought to the temperature required for the reaction in the reaction passage via the cooling / heating passage. The cooling / heating passage is a cooling passage when the medium is to be cooled and a heating passage when the medium is to be heated. The cooling / heating passage can be designed in different ways. Some non-exclusive examples are discussed in more detail below. Design variants are also conceivable in which the process medium leaving the reaction passage is in one subsequent cooling / heating passage is brought to a temperature required for further process steps.

In the embodiment described above, the first layer has at least two individual components of the device, namely at least one reaction passage and at least one cooling / heating passage. At least one channel is provided for each passage. However, the invention is not limited to a certain number of channels. In the simplest case, a single channel is provided for each passage. However, several channels can also advantageously be provided, which are then preferably arranged parallel to one another. The more channels are provided, the larger quantities of process medium can be passed through the device at the same time. On the one hand, this can significantly improve throughput. Furthermore, the installation space requirement of the device can be reduced, since the individual channels can be made significantly shorter compared to a single channel.

Furthermore, the invention is not restricted to a specific configuration and / or arrangement of the channels. Rather, the channel structure can have any dimension. In particular, the individual channels can have any size and cross-sectional shape.

The at least one reaction channel and / or the at least one cooling / heating channel can advantageously be coated with a reaction medium, preferably with a catalyst material. In such a case, the cooling / heating duct is advantageously used as a heating duct. When the process medium flows through an appropriately coated channel, it reacts with the catalyst material. These reactions are mostly exothermic, so that heat is generated. This heat must then be dissipated, which can take place, for example, via the individual components of the device provided in the second layer, as will be explained in more detail below.

The at least one first layer can preferably have at least one mixing zone for mixing at least one further medium into the process medium have, the mixing zone seen in the flow direction of the process medium is provided before and / or after the reaction passage. For example, the mixing zone can be connected to the channel inlet of a reaction channel. The process medium then enters the at least one reaction channel via the mixing zone. In the mixing zone, the process medium can first be mixed with at least one further medium, for example with air, before it enters the reaction channel.

If the first layer also has a cooling / heating passage in addition to the reaction passage, the mixing zone can advantageously be provided between the reaction passage and the cooling / heating passage, as seen in the flow direction of the process medium. It is conceivable that the mixing zone is connected to a channel outlet of the cooling / heating passage and to a channel inlet of the reaction passage. In this way, the process medium can first be brought to the desired temperature in the cooling / heating channel and mixed with other media in the subsequent mixing zone. This well-tempered mixture is then introduced into the reaction channel. In the embodiment described above, there are thus at least three individual components of the device on or in the first layer.

In a further embodiment, the at least one second layer can have at least one cooling / heating device for cooling / heating the process medium flowing through the at least one first layer. Thus, further individual components of the device are realized in the second layer. In the present case, these components are cooling or heating components, depending on whether the process medium is to be cooled or heated. The invention is not restricted to specific embodiments for the cooling / heating device. It is only important that the device is able to bring the process medium to the required temperature.

For example, it is conceivable that a thermal energy required for this is generated electrically. In this case, thermal energy can be provided by means of suitable heating elements, heating cartridges and the like. These elements can then be arranged in the second layer. In another embodiment, it is conceivable that the cooling / heating device has a channel structure with at least one channel, and that a corresponding cooling medium or heating medium flows through the channel. Of course, the invention is not limited to the two exemplary examples mentioned above.

The at least one cooling / heating device of the at least one second layer can advantageously be thermally coupled to the reaction passage of the at least one first layer. This makes it possible, for example, to allow heat generated in the reaction passage during the reaction to be dissipated via the device, so that in this case it functions as a cooling device. Likewise, the heat required for a reaction can be supplied via the device, which then functions as a heating device, as required. Since the cooling / heating device is thermally coupled to the reaction passage, the required heat exchange can take place without any problems. The cooling / heating device is then a further individual component of the device, for example a heat exchanger.

In a further embodiment, at least one cooling / heating device of the at least one second layer can be thermally coupled to the cooling / heating passage of the at least one first layer. In this way, analogous to the above, a heat exchanger can be realized, for example, which cools or heats the process medium flowing through the cooling / heating passage to the required temperature.

The cooling / heating device can advantageously have at least one channel for passing a cooling / heating medium through it. In this case, the cooling / heating device is constructed in a similar manner to the cooling / heating passage or the reaction passage, so that in this regard reference is also made to the corresponding statements above and reference is hereby made. The at least one channel is particularly advantageously designed as a microchannel. The at least one channel of the cooling / heating device can also be coated with a reaction medium, preferably with a catalyst material, in a manner analogous to the channels of the cooling / heating passage or the reaction passage.

The channels of the at least one cooling / heating device and the reaction passage and / or the cooling / heating passage can advantageously be aligned with one another in a cross-flow design. Of course, the channels can also be aligned parallel to one another. In this case, the device can be operated, for example, in the cocurrent principle or in the countercurrent principle.

The at least one second layer can preferably have at least one mixing zone for mixing at least one further medium into the process medium. The individual first and second layers are advantageously layered one above the other in such a way that the mixing zones of the first and second layers come to lie directly one above the other. In this way, the mixing zones of the first and second layer (s) form a mixing room.

The mixing room is fed with the process medium via channels of the first layer. The mixing room is additionally fed with another medium via the second layer. For this purpose, the mixing zone of the at least one second layer is preferably connected to a corresponding medium inlet via at least one supply channel (of course, several, in particular, parallel, supply channels can also be provided). The various media are mixed with one another in the mixing room before they enter the at least one reaction channel of the reaction passage as a media mixture from the mixing room.

Since all the individual components of the device are integrated in a single component, at least one central inlet for the process medium is advantageously provided, the central inlet being connected to the at least one channel of the at least one first layer via a channel inlet. Similarly, at least one central outlet for the process medium can also be provided, the central outlet being connected to the at least one channel of the at least one first layer via a channel outlet. The device according to the invention can be used particularly preferably in connection with a so-called CO pulser. In conjunction with a CO pulser, for example, the space velocity can be increased considerably. With a CO pulser, for example, it is easily possible to prevent harmful influence of carbon monoxide (CO) on the fuel cell. Such a CO pulser is described, for example, in DE 197 10 819 C1, the disclosure content of which is included in the description of the present invention. Here, a fuel cell is described in which performance losses due to impurities absorbed on the anode catalyst are to be avoided. This is achieved in that the fuel cell is connected to means which impart a positive voltage pulse to the anode of the fuel cell (CO pulses). A pulse-shaped change in the anode potential is brought about by the stamping of the voltage pulse. This pulsed change in the anode potential means that the carbon monoxide in the fuel cell is oxidized. The voltage pulses can be impressed on the fuel cell, for example, by temporarily connecting an external DC voltage source to the fuel cell via a switch.

A circuit arrangement for such a CO pulser is further described in the older patent application DE 100 20 126.1 filed by the applicant, the disclosure content of which is also included in the description of the present invention.

The fuel cell normally requires a CO concentration of less than 50 ppm. By increasing the space velocity, the component can be reduced enormously at the expense of the purity of the hydrogen generated (for example a factor of 5). The gas stream fed into the fuel cell then typically contains 500 ppm CO, which, by using the CO pulser, leads to behavior comparable to that of 50 ppm CO in the fuel cell. This enables enormous space savings. The device according to the invention described above can be part of a fuel cell system, for example, with at least one fuel cell and with a device for producing and / or preparing a fuel for the fuel cell, which is connected upstream of the fuel cell and - as described above. Optionally, the fuel cell can also be connected, at least temporarily, to a device for applying voltage pulses (CO pulser), as described above.

Such a fuel cell system makes it possible to produce the fuel required for operating the fuel cell in a particularly simple and reliable manner. The fuel cell system can advantageously have more than one fuel cell, the individual fuel cells being combined to form a fuel cell stack, or fuel cell stack.

The device for producing and / or processing fuel generally consists of a number of individual components, which can be chemical reactors such as reformers, shift reactors, reactors for selective oxidation or the like. All of these reactors can be realized with the device according to the invention. Of course, embodiments of the device are also conceivable in which several chemical reactors are formed on or in the layers. Additional components such as evaporators, heat exchangers, catalytic burners and the like are also required to operate the chemical reactors. These components can also be implemented within the individual layers of the device according to the invention.

A device according to the invention as described above is therefore used particularly advantageously as a chemical reactor.

The advantageous replaceability will be illustrated below using a non-exclusive example. The device should be designed as a chemical reactor for selective oxidation. If the device for generating and / or Processing fuel is designed as a reactor for selective oxidation, this can be constructed, for example, as follows:

The catalysts within the reaction passage can be selected so that they work with temperatures in the range 90-140 ° C. This enables the device to be automatically tempered with the cooling water drain of the fuel cell (80-90 ° C). The mass flow is large enough to drive the temperature in the integrated selective oxidation in a very narrow temperature range.

Such a reactor for selective oxidation can therefore, for example, be flanged directly to a fuel cell without the need for a pipe connection and control unit for cooling (a thermal unit). Furthermore, no piping, no gaps, no regulation and the like are necessary for the cooling.

At least one heat exchanger is integrated into the device, which serves to cool the supplied process medium.

A micromixer in the device allows the process medium to be mixed homogeneously with at least one further medium, for example with air, in the smallest space (for example 1-3 cm in length).

In addition to the reaction passage, the device has a cooling / heating passage upstream of it (selective oxidation - reactor with water cooling passage). This enables exact temperature control to the cooling water temperature (e.g. 90-100 ° C).

Finally, the layout of the device also permits multi-stage air metering and reaction passage.

The invention will now be explained in more detail using an exemplary embodiment with reference to the accompanying drawings. The only FIG. 1 shows a perspective view of an inventive device for generating and / or processing a fuel, which is designed in the form of a reactor for selective oxidation.

FIG. 1 shows a device 10 for producing and / or processing a fuel, which is designed as a layer sequence of alternately stacked layers 11, 12 with a channel structure. The device 10 is designed in microstructure technology and consists of a number of individual components, which are also designed in microstructure technology, and all of which are integrated in the device 10, so that it is designed as a single component.

In the device 10 for generating and / or processing, a fuel for a fuel cell, not shown, is brought to the required quality. Since the device 10 is designed as a chemical reactor for selective oxidation, the carbon monoxide content of the fuel is reduced to an acceptable level for the fuel cell. The device 10 can be flanged directly to the fuel cell.

A process medium, for example the fuel, is passed through the layers 11. The layers 12 serve to treat the process medium flowing through the layers 11. The process medium enters the channel inlet 30 via the central inlet 13 for the process medium and is distributed via this into cooling / heating channels 16 of a cooling / heating passage 15. The cooling / heating passage 15 represents a first individual component of the device 10 and is formed in the layers 11. The process medium flows through the channels 16 of the layers 11, the cooling / heating passage 15 serving in the present example as a cooling passage for the process medium. A channel 18 adjoins the channels 16, in which the process medium is mixed with another medium, for example air. This is a further individual component of the device 10, which is formed in the layers 11. A reaction passage 40 is then provided, as seen in the flow direction S of the process medium, which has a number of parallel reaction channels 17. This is the actual reaction passage, for example selective oxidation. To When the reaction is complete, the process medium exits the device 10 via a channel outlet 31 and the central outlet 14.

Typical dimensions for the dimensions of the channels are:

Channel width: 0.3 mm to 5 mm

Channel height: 0.1 to 1 mm

Channel length: a few cm

Wall thicknesses: 0.1 to 0.5 mm

To cool the process medium in the cooling / heating passage 15, a cooling / heating device 20 is provided in a layer 12 adjacent to the layer 11, which first consists of a first cooling / heating device 41. The cooling / heating device 41 in turn has a number of channels 23. A cooling medium flows through the channels 23, which enters the channels 23 via a cooling / heating medium inlet 21 and exits the channels 23 via a cooling / heating medium outlet 22. The cooling channels 23 are aligned with the channels 16 for the process medium in a cross-flow construction, but can also be aligned in a parallel construction.

In the area of the reaction passage 40 in layer 11, a further cooling / heating device 41 is provided, which is constructed in the same way as the device described above. The cooling / heating devices 41 are further individual components of the device 10, for example appropriately designed heat exchangers. Since the layers 11 and 12 are thermally coupled, a sufficient heat exchange between the cooling / heating devices 41 on the one hand and the reaction passage 40 or the cooling / heating passage 15 on the other hand can easily take place.

Between the channels 16 of the cooling / heating passage 15 and the channels 17 of the reaction passage 40 is the mixing zone 18, in which a further medium, for example air, is mixed into the process medium. In order to achieve complete mixing of the two media in a simple manner, the mixing zone 18 is constructed as follows. In the layer 12 there is initially provided a relatively wide channel 27 aligned with the channels 16 in a cross-flow design. The medium, for example process air, enters the channel 27 via a medium inlet 24. Medium not used in the mixing zone 18 can exit from the channel 27 via a medium outlet 25. In order to be able to mix the additional medium into the process medium stream, a number of short supply channels 26 are provided, which are aligned in parallel flow construction with the channels 16 from layer 11 and which are connected to the channel 27. The medium flowing through the channel 27 enters the mixing zone 18 via the feed channels 26. The layers 11 and 12 are arranged one above the other in such a way that the mixing zones 18 of the individual layers 11 and 12 come to lie directly one above the other. In this way, a mixing space 19 is created. The mixing space 19 is charged with process medium via the channels 16 and with another medium, for example with air, via the feed channels.

The number and design of the feed channels 26 ensure that the additional medium can enter the mixing space 19 over the entire width of the mixing zone 18, which leads to a particularly good, thorough mixing of the two media.

The medium mixture formed in this way is then introduced into the reaction channels 17, where the actual reaction takes place. The heat generated during the reaction taking place in the reaction passage 40 is absorbed and transported away via the cooling / heating device 41 thermally coupled to the reaction passage 40, which in the present example is designed as a cooling device. For this purpose, the heat is transferred to a cooling medium flowing through the channels 23.

Further possible uses of the reactor structure described are given in the list below, which is not exhaustive, however. It goes without saying that other possible uses are also conceivable: 1. In addition, of course, any combinations of the solutions described here are also conceivable. Device for heating, evaporating and superheating process air for a fuel cell system with an integrated mixer (18, 19, 24, 25, 26, 27) for metering in process gases. In this unit, the heat required for the evaporation or overheating is provided, for example, by hot burned fuel cell exhaust gases. These gases are fed to the heat exchanger passages 20 (now heating passages) and passed through the heating passages 20, for example in a cross-counterflow construction (series connection of the passages 20 with flow direction against process gas flow). If there are still unburned exhaust gases that still contain energy, these can be burned (catalytically) in the channels 23 of the passages 20. The heat generated can then be used to heat the process gas. For this purpose, the channels 23 in passage 20 can be coated with an oxidation catalyst so that unburned exhaust gases from the fuel cell burn and thus release heat. 3 fluids are usually required for the preparation of fuel for fuel cells: 1. fuel (gasoline / natural gas), 2. water (steam), 3. air. These fluids must be mixed very homogeneously before entering the reformer. In order to achieve a very high integration density, it can make sense not only to meter in the air in the mixing passage but also all three necessary fluids (e.g. gasoline, water, air for a gasoline system or natural gas, water, air for a natural gas system) in one passage to mix. The layers would then be arranged alternately (for example, 1st water or steam, 2nd gasoline / natural gas, 3rd air: stacking sequence, for example 1st, 2nd, 1st, 2nd 3rd etc.) The passage 27 would then not more would connect the inlets 24 and 25 but would alternately be connected to 24 or 25 and could thus enable the described supply of gasoline / natural gas (for example 24) and air (for example 25) in a mixing unit.

2. Device for a multi-stage shift reactor with adapted temperature zones or temperature gradients. When processing fuel for a fuel cell system, the proportion of CO in the process gas must be reduced after the reformer (T approx. 700-800 ° C). This is through Shift reactors (T approx. 200 -400 ° C) reached. The higher the temperature of the process gas, the higher the proportion of CO in the process gas. As the temperature drops, the CO in the shift reactor is converted into CO2. However, the gas warms up again during this process. In addition, the reaction proceeds faster at higher temperatures (400 ° C) than at lower temperatures (200 ° C). It is therefore desirable to have the shift reaction first controlled at higher temperatures and then at lower temperatures. The device described allows the high and low temperature shift catalytic converters to be fitted in the passages 16 and 17 and a reaction controlled by the cooling passages to take place. In this case, the mixing passage is not absolutely necessary and can therefore be omitted. However, the mixing passage can also be used to feed additional water vapor into the system in order to improve the mode of operation of the shift reactors.

3. Device as described, however, the functional units are repeated several times, so that a reactor with several shift stages and stages for selective oxidation can also be integrated.

4. Device as described but with an additional integrated reformer and evaporator / mixer, so that a fully integrated system is created.

LIST OF REFERENCE NUMBERS

10 = device for producing and / or processing a fuel

11 = first layer

12 = second layer

13 = central inlet for a process medium

14 = central outlet for a process medium

15 = cooling / heating passage

16 = cooling / heating channel

17 = reaction channel

18 = mixing zone

19 = mixing room

20 = cooling / heating device

21 = cooling / heating medium inlet

22 = Cooling / heating medium outlet

23 = channel

24 = medium inlet

25 = medium outlet

26 = feed channel

27 = channel

30 = channel entry

31 = channel outlet

40 = reaction passage

41 = cooling / heating device

Flow direction of the process medium

Claims

claims

1. Device for producing and / or processing a fuel for a fuel cell, with a number of individual components, characterized in that the device (10) is designed as a layer sequence of individual layers (11, 12), with at least a first layer (11) for passing a process medium, which has at least in regions a channel structure with at least one channel (16, 17), and with at least one second layer (12), which has at least one component for treating the process medium flowing through the at least one first layer (11) that the device (10) is designed as a single component in microstructure technology and that all individual components are integrated in the one, single component.

2. Device according to claim 1, characterized in that the at least one channel (16, 17) of the at least one first layer (11) is designed as a microchannel.

3. Device according to claim 1 or 2, characterized in that the at least one first layer (11) and the at least one second layer (12) are thermally coupled to one another at least in regions.

4. Device according to one of claims 1 to 3, characterized in that the at least one first layer (11) has at least one reaction passage (40) and that in the reaction passage (40) at least one reaction channel (17) is formed.

5. The device according to claim 4, characterized in that the at least one first layer (11) has at least one cooling / heating passage (15), that in the cooling / heating passage (15) at least one cooling / heating channel ( 16) is formed and that the cooling / heating passage (15) seen in the flow direction (S) of the process medium is provided before and / or after the reaction passage (40).

6. The device according to claim 4 or 5, characterized in that the at least one reaction channel (17) and / or the at least one cooling / heating channel (16) is coated with a reaction medium, preferably a catalyst material.

7. Device according to one of claims 4 to 6, characterized in that the at least one first layer (11) has at least one mixing zone (18) for adding at least one further medium to the process medium and that the mixing zone (18) in the direction of flow (S) the process medium seen before and / or after the reaction passage (40) is provided.

8. The device according to claim 7, insofar as referred to one of claims 5 or 6, characterized in that the mixing zone (18) seen in the flow direction (S) of the process medium between the reaction passage (40) and the cooling / heating passage (15) is provided.

9. Device according to one of claims 1 to 8, characterized in that the at least one second layer (12) has at least one cooling / heating device (41) for cooling / heating of the process medium flowing through the at least one first layer (11).

10. The device according to claim 9, as far as related to one of claims 4 to 8, characterized in that at least one cooling / heating device (41) of the at least one second layer (12) thermally with the reaction passage (40) of the at least a first Layer (11) is coupled.

11.The device according to claim 9, insofar as referred to one of claims 5 to 8, characterized in that at least one cooling / heating device (41) of the at least one second layer (12) thermally with the cooling / heating passage (15) the at least one first layer (11) is coupled.

12. Device according to one of claims 9 to 11, characterized in that the cooling / heating device (41) has at least one channel (23) for passing a cooling / heating medium.

13. The apparatus according to claim 12, characterized in that the at least one channel (23) is coated with a reaction medium, preferably a catalyst material.

14. The apparatus according to claim 12 or 13, characterized in that the channels (23, 16, 17) of the at least one cooling / heating device (41) and the reaction passage (40) and / or the cooling / heating passage (15th ) are aligned with each other in cross-flow construction.

15. The device according to one of claims 1 to 14, characterized in that the at least one second layer (12) has at least one mixing zone (18) for mixing in at least one further medium to the process medium.

16. The apparatus according to claim 15, insofar as related to one of claims 7 to 14, characterized in that the mixing zones (18) of the first and second layers (11, 12) form a mixing space (19).

17. The apparatus according to claim 15 or 16, characterized in that the mixing zone (18) of the at least one second layer (12) via at least one feed channel (826) is connected to a medium inlet (24).

18. Device according to one of claims 1 to 17, characterized in that it has at least one central inlet (13) for the process medium and that the central inlet (13) via a channel inlet (30) with the at least one channel (16 , 17) the at least one first layer (11) is connected.

19. Device according to one of claims 1 to 18, characterized in that it has at least one central outlet (14) for the process medium and that the central outlet (14) via a channel outlet (31) with the at least one channel (16, 17) of the at least one first layer (11) is connected.

20. Use of a device according to one of claims 1 to 19 as a chemical reactor, in particular as a chemical reactor for selective oxidation.

21. Use of a device according to one of claims 1 to 20 as a chemical reactor that at least one individual component is designed for integrated selective oxidation in one or more stages, wherein channel structures (16, 17) through which process gas flows are provided with a catalyst, and that at least one individual component is designed as a mixer (24, 25, 26, 27, 18, 19).

22. Device according to one of claims 1 to 19, characterized in that at least one individual component is designed as an integrated evaporator / superheater, wherein one or more mixers can be provided.

23. The device according to claim 22, characterized in that a catalyst coating is provided in the provided heating passages (20).

24. Device according to one of claims 1 to 19, characterized in that several individual components together as an integrated (evaporator) / superheater / reformer with integrated mixing passages and catalyst in the heating passages (20) (oxidation catalyst) and catalyst in the process channels (reformer catalyst) are.

25. The device according to one of claims 1 to 19, characterized in that it forms a fully integrated reactor with all reactors for fuel processing (evaporator / superheater, reformer, shift reactors, selective oxidation).

26. Device according to one of claims 1 to 19, characterized in that it is designed as an integrated shift stage with a temperature gradient or a plurality of temperature zones with a catalyst (shift catalyst) in the process gas passages (16, 17).

27. Device according to one of claims 1 to 19, characterized in that channel structures in adjacent layers run obliquely, preferably transversely to one another, and are connected in a cross-countercurrent connection, so that a cooling medium flowing in channel structures (20), preferably an unformed one Process gas or part of it (eg water vapor) is heated and thereby serves as cooling for the process gases (16, 17).

28. Use of a device according to one of claims 1 to 27, however, not restricted to use in a fuel cell system.

29. Several devices according to one of claims 1 to 28 stacked one above the other and connected in series and thermally decoupled from one another by an insulation medium.

30. Device according to claims 1 to 29, wherein the layers are made of different materials (including metals, alloys, ceramics, plastics, glass, carbon) and / or thicknesses to influence the thermal behavior.