Filter, electrochemical cell device

Abstract

The invention relates to a filter (100) for cleaning a fluid in an electrochemical cell device (10), preferably a fuel cell device (10), wherein the filter (100) comprises a filter element (102) which is porous and is designed for filtering particles from the fluid, and wherein the filter (100) comprises at least one filter layer (112) which is designed to remove gaseous impurities from the fluid. It is proposed that the filter element (102) be coated with the filter layer (112).

Description

[0001] The invention relates to a filter for purifying a fluid in an electrochemical cell device according to the preamble of the independent claim. The invention further relates to an electrochemical cell device comprising such a filter. State of the art

[0002] The performance and lifespan of fuel cell stacks in fuel cell devices depend critically on the purity of the supplied airflow. Even small amounts of impurities, both gaseous and solid, can lead to irreversible damage to the stack and significantly reduce its performance. Disclosure of the invention Advantages

[0003] The present invention describes a filter for cleaning a fluid in an electrochemical cell device, preferably a fuel cell device, wherein the filter comprises a filter element which is porous and is designed for filtering particles from the fluid, and wherein the filter has at least one filter layer which is designed to remove gaseous impurities from the fluid. According to the invention, the filter element is coated with the filter layer.

[0004] The filter according to the invention combines the function of particle separation with the removal of gaseous contaminants, thus enabling improved protection of a downstream electrochemical cell device. In the context of the present invention, a fluid is understood to be, in particular, a liquid and / or a gas.

[0005] A porous filter element is understood to be, in particular, a structured element that has a spatial extent in three dimensions and is designed to interact with a gas flow. Due to its porosity, the filter element has an increased surface area in order to maximize the efficiency of chemical or physical processes, such as particle filtration.

[0006] Examples of such filter elements include honeycomb structures, which consist of numerous channels arranged parallel to the gas flow direction and have high wall porosity to increase their capacity to trap contaminants. Plate bundles, composed of several parallel plates, provide an increased surface area, and foam structures, such as open-cell or closed-cell foams, offer a high specific surface area and, due to their structure, enable effective fluid flow. Other forms include extrudates, which are produced by extrusion and have a defined three-dimensional structure, such as...Cylindrical or prismatic shapes, or the shape of a honeycomb structure, as well as pellets, tablets, and granules, which can be arranged as smaller, shaped particles in a bulk or layer to provide an increased surface area. Spheres, which can be arranged as spherical particles in a bulk or layer, as well as fibers, mats, and knitted fabrics, which, as textile-like structures made of fibers, offer a high specific surface area and can be present in various arrangements such as nonwovens, woven, or knitted materials, are also suitable filter elements.

[0007] A filter element can consist of various materials, selected according to the application and operating conditions. Suitable materials include ceramics, such as cordierite; metals and alloys, such as special steels like 1.4767; and alkaline earth metal compounds, such as oxides of magnesium (Mg), barium (Ba), and strontium (Sr). Non-ferrous metal compounds, such as nickel oxides, and micro- and mesoporous materials, such as zeolites, are also suitable materials for the manufacture of filter elements.

[0008] Advantageously, the porous filter element comprises a microporous and / or mesoporous material, in particular a zeolite. Microporous and mesoporous materials, especially zeolites, offer a very large surface area due to their pore structure, which increases the filter element's capacity to bind particles. The pores can act like traps for the particles, thus advantageously preventing them from escaping into the purified fluid.

[0009] Precious metal, alkaline earth metal, alkali metal (especially sodium), and / or hydrogen (H) forms of zeolites are particularly suitable. Especially suitable zeolites include, for example, the types FAU (faujasite), BEA (beta), CHA (chabazite), MFI (ZSM-5), FER (ferrierite), AEI (SSZ-39), and MOR (mordenite). These zeolites are characterized by their high specific surface area and their ability to capture and bind not only particles but also gaseous impurities.

[0010] A filter element is advantageously designed to provide an enlarged surface area, thereby maximizing the efficiency of chemical or physical processes in the operation of electrochemical cell devices. Specifically, it serves to capture and retain impurities from the fluid, thus reducing the contamination of the fluid stream. Through the specific design and material selection of the filter element, a high pollutant retention capacity can be achieved while simultaneously minimizing gas backpressure to improve the overall process efficiency.

[0011] In the context of the present invention, "particles" shall be understood to mean, in particular, liquid and / or solid particles. The filter layer is designed to remove gaseous impurities from the fluid stream. In particular, it is conceivable that the filter layer removes the gaseous impurities by chemical bonding. For example, the filter layer may comprise a protective material designed to form a chemical bond with the gaseous impurities. These gaseous impurities may include, for example, hydrogen sulfides such as H₂S, phosphorus, and / or ammonia (NH₃). The impurities are fixed by their bonding to the protective material.

[0012] The term "protective material" refers in particular to substances or mixtures of substances designed to react with gaseous impurities to form stable compounds. The protective material may, in particular, contain alkaline earth metals—especially magnesium, barium, and / or strontium—and / or alkaline earth metal compounds, especially their oxides, and / or alkali metals and / or alkali metal compounds, especially their oxides. The protective material may also contain non-ferrous metals and / or non-ferrous metal compounds—especially nickel oxides. Mixtures and / or mixed oxides of alkaline earth metals, alkaline earth metal compounds, non-ferrous metals, non-ferrous metal compounds, alkali metals, and / or alkali metal compounds are also conceivable.

[0013] It is also advantageous for the filter layer to have a protective material and a carrier material. This increases the efficiency of binding gaseous contaminants and extends the filter's service life. In particular, this improves the bond between the protective material and the filter element. The carrier material can increase the mechanical stability and service life of the protective layer. It is also beneficial for the filter element to be coated with the carrier material.

[0014] Typically, the support material contains one or more metal oxides. For example, the support material may contain titanium oxide, silicon oxide, aluminum oxide, and / or zirconium oxide, advantageously with high porosity. It is also possible for the support material to contain neodymium oxide, cerium oxide, praseodymium oxide, hafnium oxide, yttrium oxide, and / or rare earth elements, and mixtures and mixed oxides thereof. It is also conceivable that the support material contains molecular sieves such as zeolites.

[0015] The protective material is typically applied to the substrate, advantageously in the form of nanoparticles. In particular, the protective material is applied to a substrate already present on the base material. For example, the protective material can be applied by impregnation, especially by dry impregnation and / or wet impregnation. The aim is to distribute a desired amount of the protective material to specific locations within the internal pore structure of the substrate and to fix it there in one or more subsequent steps. Fixation can be achieved, for example, by changing process parameters, by adding substances – especially for changing pH values ​​– by changing the oxidation state and / or process temperature; in particular, processes for drying, calcination, and / or reduction are conceivable.

[0016] For example, to produce the substrate material, an aqueous powder suspension of metal oxides can be applied to the base body. Such a powder suspension is also known as a washcoat. This powder suspension is then partially dried, allowing the substrate material to form on the base body—especially the three-dimensional component. Subsequently, the protective material, particularly metals in their aqueous acid or salt solutions, can be impregnated onto the substrate material and then activated by calcination.

[0017] The protective material and / or filter layer can be applied to the filter, just like the optional support material, using standard catalyst manufacturing processes familiar to experts. Processes for applying slurries to three-dimensional components with surfaces have proven particularly effective.

[0018] An electrochemical cell device or cell device is understood to be, in particular, a device designed for the electrochemical reaction of at least two fluids. The cell device comprises an electrochemical cell unit that electrochemically reacts the two fluids, as well as components that supply the cell unit with electrical energy (i.e., supply and / or remove electrical energy), and components that supply the cell unit with the two fluids. This supply can be active—for example, via supply lines, pumps, fluid reservoirs, etc.—or passive—for example, using ambient air as the fluid—without active transport. Advantageously, the cell device also includes components for the removal and / or recycling of the reacted fluids.Advantageously, the cell device also includes components for heat transfer, particularly for temperature control of the cell unit, for example, for the utilization of waste heat. Examples of cell devices are fuel cell devices or electrolysis devices. The filter according to the invention can be used at different positions in the fluid flow path of the electrochemical cell device. Advantageously, the filter can be arranged upstream of the electrochemical cell unit. This has the advantage that the electrochemical cell unit can be protected from chromium or chromium compounds. For example, the filter can be used for pretreatment of the fluids before they are supplied to the electrochemical cell unit.It is also possible that the filter is arranged downstream of the electrochemical cell unit in terms of flow technology, so that the fluids processed in the electrochemical cell can be post-treated and any chromium present there can be removed.

[0019] In this context, an electrochemical cell unit refers specifically to a unit comprising multiple electrochemical cells. An electrochemical cell unit is also called an electrochemical stack or simply a stack. Typically, the electrochemical cells are stacked on top of each other. Advantageously, a cell can have a plate-shaped support on which the functional layers, particularly electrolyte layers, are arranged, as well as a plate-shaped interconnector with raised sections. The interconnector is positioned between the cell's support and another support of an adjacent cell. The interconnector establishes electrical contact between the adjacent cells. Furthermore, the interconnector creates a gap, and thus a flow-through space, between the cell's support and another support of an adjacent cell.This enables the supply of fluids to the substrates or the functional layers arranged on them. Advantageously, the cells are electrically connected in series. It is also conceivable that the cells are electrically connected in parallel. The cells can advantageously be arranged in a stack on a common chassis or substrate, or in a common housing. Examples of electrochemical cell units are fuel cell units or electrolysis cell units.

[0020] An electrochemical cell is understood to be, in particular, an arrangement that provides usable electrical energy through chemical reactions or is intended for the chemical production or conversion of substances by applying a voltage. An electrochemical cell has at least two or more functional layers. The functional layers comprise at least two electrode layers and a separating layer or electrolyte layer. The electrode layers each function as an electron conductor and are conductively connected to the separating layer or electrolyte layer. Also important for the electrode layers are ion transport and catalytic activity or oxygen exchange capacity between the electrode layer and the gas phase. The separating layer or electrolyte layer functions, in particular, as an ion conductor. Furthermore, the separating layer or electrolyte layer...Electrolyte layer provided for the separation of the two gas compartments, for example the separation between air and fuel gas in a fuel cell.

[0021] In particular, the term "cell" or "electrochemical cell" shall be understood to mean a fuel cell or an electrolysis cell. In this context, the term "fuel cell" or "electrolysis cell" shall be understood to mean, in particular, at least a part, especially a subassembly, of a fuel cell system, in particular a solid oxide fuel cell system, and / or an electrolysis cell device, in particular a high-temperature electrolyzer. In particular, the electrochemical cell may also comprise the entire fuel cell, in particular the entire solid oxide fuel cell, the entire electrolyzer, in particular the entire high-temperature electrolyzer, a stack of fuel cells and / or electrolysis cells, and / or a combination of several stacks of fuel cells and / or electrolysis cells.Preferably, the electrochemical cell is designed to convert a fuel into electrical energy in an electrochemical combustion process by supplying an oxidant. Alternatively or additionally, the electrochemical cell is designed to separate a fluid into at least two components in a separation process by supplying electrical energy. "Designed" is understood to mean, in particular, specially configured, specially designed, and / or specially equipped. The phrase "designed" means, in particular, that an object fulfills and / or performs this specific function in at least one application and / or operating state.

[0022] The cell, or electrochemical cell, can be, in particular, an electrolysis cell, especially a solid oxide electrolysis cell (SOEC). Alternatively, the electrolysis cell can also be a proton-conducting electrolysis cell, or protonic ceramic electrolysis cell (PCEC), based on a proton-conducting oxide (PCO). The electrochemical cell can also be a fuel cell, for example, a solid oxide fuel cell (SOFC). It is also conceivable that the fuel cell is designed like a proton conductor or proton-conducting oxide (PCO). Such fuel cells are also referred to as protonic ceramic fuel cells (PCFC).A fuel cell is specifically designed to convert at least one chemical reaction energy of at least one, in particular continuously supplied, fuel gas, in particular hydrogen, and at least one oxidizing agent, in particular oxygen, into electrical energy.

[0023] A fuel cell device is understood to be, in particular, a device that forms a component, especially a functional one, particularly a structural and / or functional component, of a fuel cell system, or the entire fuel cell system. In this context, a fuel cell system is understood to be, in particular, a system for the stationary and / or mobile generation of, in particular, electrical and / or thermal energy using at least one fuel cell unit.

[0024] A fuel cell system comprises one or more fuel cell units. Typically, a fuel cell system includes components and lines designed to supply fuel and air to the fuel cell unit. Furthermore, a fuel cell system includes components and lines for removing exhaust gases from the fuel cell unit. Advantageously, fuel cell systems include a recirculation circuit comprising components and lines designed to return unreacted fuel and / or unreacted air to the fuel cell unit. Overall, a fuel cell system includes at least one or more fans designed to convey a fluid, in particular a gaseous fluid. The fluid can be, in particular, fuel, air, exhaust gas, or a combination thereof.The blowers can be, in particular, air supply blowers, fuel supply blowers, exhaust gas exhaust blowers, and / or recirculation blowers. Advantageously, the fuel cell system includes one or more heat exchangers, especially to recover heat from the exhaust gas, or more specifically, the anode and cathode exhaust gases, and to transfer this heat back to the fluids supplied to the fuel cell unit—especially air, fuel, and / or recirculated fluid. The terms heat exchanger and heat transfer unit are used synonymously here.

[0025] Advantageous further developments of the filter are possible due to the features listed in the dependent claims.

[0026] The filter is further improved by arranging the filter layer on the inlet surface of the filter element relative to the fluid. This ensures that the filter layer comes into direct contact with the contaminated fluid and that the gaseous contaminants can be effectively removed before they reach the filter element.

[0027] The term "inlet surface" shall be understood to mean, in particular, a surface of the filter element which is designed so that, during operation of the filter, the fluid primarily flows into the filter element through this surface, and in particular into the porous volume of the filter element.

[0028] It is also advantageous if the filter element has multiple channels extending from an inlet side to an outlet side, with a plurality of inlet channels, representing a first subset of the total channels, each featuring a closure on their respective outlet side. These channels with closures allow for controlled fluid flow through the filter element, thereby improving the efficiency of particle and gas filtration. During filter operation, the closure directs the fluid from the inlet channels into the porous filter element, thus enhancing particle filtration.

[0029] For example, the filter element can be designed as a honeycomb structure with channels, made of a porous material. Alternatively, the filter element could be designed as a bundle of plates made of a porous material – for example, woven fabric – with the plates wrapped around and / or intertwined.

[0030] The closure can, for example, be designed as a plug.

[0031] The filter is further improved by the addition of a closure on the inlet side of multiple outlet channels, which constitute a second subset of the channels. The placement of the closures on the outlet channels ensures a uniform distribution of the fluid across the entire filter surface, thus guaranteeing optimal utilization of the porous filter element's filter volume.

[0032] Advantageously, a channel can belong only to the first subset or only to the second subset; advantageously, a channel is either only an inlet channel or only an outlet channel. Advantageously, exactly every channel is either an inlet channel or an outlet channel. Advantageously, the first subset and the second subset are equal in size or approximately equal in size.

[0033] It is also advantageous if each inlet channel is adjacent to at least one outlet channel. The adjacent arrangement of inlet and outlet channels allows for a short filter section and thus a low pressure drop within the filter. In this way, the fluid in the filter element flows primarily through the porous volume between the inlet and outlet channels, essentially through the walls between the channels. Such filters are therefore sometimes also referred to as wall-flow filters.

[0034] The filter is further improved by arranging the filter layer, at least partially, within the inlet channels. Placing the filter layer in the inlet channels increases the contact time between the fluid and the filter layer during operation, thereby further enhancing the efficiency of removing gaseous contaminants. This also maximizes the effective flow cross-section of the filter layer.

[0035] It is also advantageous if the filter layer has a protective material which contains at least one alkaline earth metal and / or one alkali metal or one alkaline earth metal compound and / or one alkali metal compound, in particular barium or one barium compound and / or strontium or one strontium compound.

[0036] Both barium and strontium react with H₂S to form stable sulfides (BaS, SrS). These sulfides are solids and remain in the filter layer, thus preventing H₂S from reaching the electrochemical cell device during operation. Similar to hydrogen sulfide, barium and strontium also form stable phosphates with phosphorus, such as Ba₃(PO₄)₂ or Sr₃(PO₄)₂. These phosphates are also solids and are retained in the filter layer during operation. Although the binding of ammonia to barium and strontium is less strong than that of H₂S and phosphorus, these alkaline earth metals can still contribute to ammonia immobilization by forming amide compounds (such as Ba(NH₂)₂, Sr(NH₂)₂) or by binding ammonia through physisorption.Furthermore, barium and strontium in particular are reactive metals and exhibit high thermal stability, which is especially advantageous when using the filter in high-temperature operation of electrochemical cell devices, such as solid oxide fuel cells.

[0037] The filter is further improved by a differential pressure sensor, which is designed to detect the differential pressure across the filter element. This sensor allows monitoring of the filter's contamination level and signals when a filter change and / or cleaning is necessary. For example, a cleaning mode could be implemented to clean a filter clogged with particles, perhaps by increasing the temperature – for instance, by burning off the filter element – ​​or by flushing it with a cleaning agent.

[0038] The present invention further describes an electrochemical cell device, in particular a fuel cell device, comprising an electrochemical cell unit and at least one filter according to the present invention.

[0039] Integrating the filter into the electrochemical cell device enables a compact design and effective protection of the electrochemical cells from gaseous contaminants and particles. By combining the functionality of cleaning the fluid of both particles and gaseous contaminants in a single unit, a compact and simply constructed filter is provided, which also reduces the complexity of the electrochemical device. This eliminates the need for a fluidic interconnection of multiple filter units, for example, one for particles and one for gaseous contaminants.

[0040] The present invention further describes an electrochemical cell device with a filter which is arranged in an air supply line in the direction of airflow immediately upstream of the electrochemical cell unit. By positioning the filter in the air supply line, the air is effectively cleaned before entering the electrochemical cell unit, thereby increasing the service life and performance of the electrochemical cells. This is particularly advantageous for fuel cell devices, as fuel cell units are especially sensitive to airborne contaminants; in particular, sulfur compounds can poison the cathode. Drawings

[0041] The drawings show exemplary embodiments of the filter and an electrochemical cell device incorporating the filter, which are explained in more detail in the following description. They show Fig. 1 a schematic representation of the fluid-technical circuitry of an electrochemical cell device and Fig. 2 a schematic representation of a filter. Description

[0042] In Fig. Figure 1 shows a schematic circuit diagram of an electrochemical cell device 10. The electrochemical cell device 10 is, by way of example, a fuel cell device 10. In the illustrated embodiment, the fuel cell device 10 is designed as a dual-fuel fuel cell device 10, which can be operated with hydrogen, natural gas, or a mixture of both. It has two fuel sources 14, one for hydrogen and one for natural gas, which can be used alone or in combination. The fuel cell device 10 comprises a fuel cell unit 12, which is, by way of example, designed as a SOFC fuel cell stack.

[0043] The fuel cell unit 12 is fluidically connected to a first fuel source 14a via a first fuel supply line 16a. More precisely, an anode side 12b of the fuel cell unit 12 is fluidically connected to the first fuel source 14a via the first fuel supply line 16a. In this way, a first fuel, in this case hydrogen, can be supplied to the fuel cell unit 12 or its anode side 12b.

[0044] For example, the first fuel source 14a is a gas connection for an external fuel supply line that provides hydrogen. Also for example, downstream of the first fuel source 14a in the first fuel supply line 16a, a first mass flow controller 46a for the first fuel is directly connected. In this way, the fuel flow required for the operation of the fuel cell unit 12 can be adjusted.

[0045] Additionally, the fuel cell device 10 has a second fuel source 14b. The fuel cell unit 12 is fluidically connected to the second fuel source 14b via a second fuel supply line 16b. More precisely, the anode side 12b of the fuel cell unit 12 is fluidically connected to the second fuel source 14b via the second fuel supply line 16b. In this way, a second fuel, in this case natural gas, can be supplied to the fuel cell unit 12 or its anode side 12b. For example, the second fuel source 14b is a gas connection for an external fuel supply line that provides natural gas.

[0046] As an example, a second mass flow controller 46b for the second fuel is connected directly downstream of the second fuel source 14b in the flow direction of the second fuel in the second fuel supply line 16b. In this way, the fuel flow required for the operation of the fuel cell unit 12 can be adjusted. By adjusting the first mass flow controller 46a and the second mass flow controller 46b accordingly, the mixture of the first fuel and the second fuel supplied to the fuel cell unit 12 can be adjusted.

[0047] The first fuel supply line 16a and the second fuel supply line 16b are fluidically connected at a first mixing section 40a. During operation of the fuel cell device 10, the first fuel and the second fuel mix at the first mixing section 40a. From the first mixing section 40a onwards, the first fuel supply line 16a and the second fuel supply line 16b merge to form a common fuel supply line 16, which is designed to deliver the mixture of the two fuels to the fuel cell unit 12. The first mixing section 40a is located in the recirculation circuit 36. The exact position of the first mixing section 40a relative to the other components is shown below. In particular, the first fuel supply line 16a is fluidly connected to the fuel supply line 16. In particular, the second fuel supply line 16b is fluidly connected to the fuel supply line 16.In particular, the fuel supply line 16 is directly connected to the fuel cell unit 12 or its anode side 12b in terms of flow technology.

[0048] A reformer 64 is arranged on the fuel supply line 16. The reformer 64 is designed to reform the fuel, in particular the second fuel, especially the natural gas. In this way, the fuel—especially the second fuel, preferably the natural gas—is converted in the reformer 64 into a reformed fuel, at least partially. The reformer 64 is required particularly in operating conditions in which natural gas, or predominantly natural gas, is supplied to the fuel cell unit 12. In the exemplary embodiment, the reformer 64 is arranged in the flow direction of the mixture of the two fuels in the common fuel supply line 16, directly upstream of the fuel cell unit 12.

[0049] The fuel cell unit 12 is fluidically connected to an air source 18 via an air supply line 20. More precisely, a cathode side 12a of the fuel cell unit 12 is fluidly connected to the air source 18 via the air supply line 20. In this way, the fuel cell unit 12, or rather its cathode side 12a, can be supplied with air during operation. As an example, an air blower 48 is fluidically arranged on the air supply line 20 between the air source 18 and the fuel cell unit 12. The air blower 48 is designed to supply air to the fuel cell unit 12, or rather its cathode side 12a. Advantageously, the air blower 48 is controllable, or rather, the airflow strength can be adjusted. In this way, the airflow required for the operation of the fuel cell unit 12 can be set. In the exemplary embodiment, the air source 18 is designed as an opening for outside air which has an air filter.The air filter is designed to filter pollutants and / or impurities out of the air.

[0050] In the fuel cell unit 12, the fuel or reformed fuel is electrochemically converted during operation with the help of oxygen from the air, generating electrical energy and heat. The electrical energy is absorbed and converted, for example, by power electronics connected to the fuel cell unit 12; for instance, the direct current from the fuel cell unit 12 can be converted into alternating current for external use. For clarity, the power electronics are shown in Fig. 1 not shown.

[0051] Following the electrochemical reaction in the fuel cell unit 12, the exhaust gas or cathode exhaust gas generated on the cathode side 12a is discharged from the fuel cell unit 12 via a cathode exhaust line 24a. The cathode exhaust line 24a is fluidically connected to the fuel cell unit 12, specifically to its cathode side 12a. The exhaust gas or anode exhaust gas generated on the anode side 12b is discharged from the fuel cell unit 12 via an anode exhaust line 24b. The anode exhaust line 24b is fluidically connected to the fuel cell unit 12, specifically to its anode side 12b. The anode exhaust gas may contain unreacted fuel as well as potentially unreformed fuel.

[0052] The fuel cell unit 12, or rather its cathode side 12a, is fluidically connected to an afterburner 26 via the cathode exhaust line 24a. In this way, during operation, the cathode exhaust can be routed from the fuel cell unit 12 to the afterburner 26 via the cathode exhaust line 24a. The fuel cell unit 12, or rather its anode side 12b, is fluidically connected to the afterburner 26 via the anode exhaust line 24b. The anode exhaust line 24b includes a flow divider 34 between the fuel cell unit 12 and the afterburner 26. The flow divider 34 is fluidly connected to a recirculation line 36.It is provided that the anode exhaust gas flowing from the anode side 12b during operation is split at the flow divider 34 into a first partial flow and a second partial flow, wherein the first partial flow is fed to the afterburner 26 via the anode exhaust line 24b and the second partial flow is fed to a recirculation circuit 38 via the recirculation line 36. The recirculation line 36 is fluidically connected to the recirculation circuit 38, or rather, it forms part of the recirculation circuit 38.

[0053] By means of the afterburner 26, the anode exhaust gas, or any unreacted and / or unreformed fuel it may contain, is reacted during operation with the addition of the cathode exhaust gas or the oxygen it contains from the air, thereby generating additional heat. In the exemplary embodiment, the afterburner 26 is a catalyst for the oxidation of methane and hydrogen and is designed as a catalytic afterburner. The afterburner 26 is fluidically connected to an exhaust outlet 30 via an exhaust line 28. During operation, the exhaust gases are routed out of the fuel cell device 10 via the exhaust line 28 and the exhaust outlet 30.

[0054] Advantageously, during operation, the waste heat from the exhaust gases of the fuel cell unit 12, in particular the cathode exhaust gas and the anode exhaust gas or the exhaust gas of the afterburner, is fed back to the fuel cell unit 12. In the exemplary embodiment, the fuel cell device 10 has a cathode heat exchanger 32a. The cathode heat exchanger 32a is designed to transfer heat from the exhaust gases flowing from the fuel cell unit 12 or the afterburner 26 to the air, which is supplied to the fuel cell unit 12 or its cathode side 12a via the air supply line 20. In this way, the efficiency of the fuel cell device 10 can be increased. In the exemplary embodiment, the cathode heat exchanger 32a is arranged upstream of the fuel cell unit 12 on the air supply line 20 with respect to the airflow direction.

[0055] In the exemplary embodiment, a filter 100 is arranged in the air supply line 20 in the direction of airflow immediately upstream of the fuel cell unit 12. By way of example, the filter 100 is arranged in the air supply line between the cathode heat exchanger 32a and the fuel cell unit 12. The filter 100 is designed to filter particles from the air by means of a porous filter element 102 and gaseous contaminants by means of a filter layer 112. In this way, contamination of the fuel cell unit 12 can be reduced or prevented. The filter element 102 and the filter layer 112 are in Fig. 1 not visible. The filter 100 including filter element 102 and the filter layer 112 are in Fig. 2 is shown in more detail and explained further in the accompanying character description.

[0056] Advantageously, the cathode heat exchanger 32a is arranged on the air supply line 20 downstream of the air blower 48 with respect to the air flow direction. In the exemplary embodiment, the cathode heat exchanger 32a is arranged on the exhaust gas line 28 downstream of the afterburner 26 with respect to the exhaust gas flow direction. In particular, the afterburner 26 is fluidically connected to the cathode heat exchanger 32a via the exhaust gas line 28. This is illustrated by example in the Fig. In the embodiment shown in Figure 1, an adjustable air bypass line 66 is arranged on the air duct 20, which is designed to direct an adjustable portion of the airflow past the cathode heat exchanger 32a. In this way, the temperature of the air arriving at the fuel cell unit 12 can be adjusted.

[0057] In the exemplary embodiment, the fuel cell device 10 has an anode heat exchanger 32b. The anode heat exchanger 32b is designed to transfer heat from the anode exhaust gases flowing from the fuel cell unit 12 or its anode side 12b to the fuel, which is supplied to the fuel cell unit 12 or its anode side 12b via the fuel supply line 16. In this way, the efficiency of the fuel cell device 10 can be further increased. In the exemplary embodiment, the anode heat exchanger 32b is arranged upstream of the fuel cell unit 12 in the fuel supply line 16 with respect to the fuel flow direction. By way of example, the anode heat exchanger 32b of the fuel supply line 16 is arranged upstream of the reformer 64 in the fuel flow direction.In the exemplary embodiment, the anode heat exchanger 32b is arranged fluidically downstream of the fuel cell unit 12 and downstream of the flow divider 34 on the recirculation line 36 with respect to the flow direction of the anode exhaust gas. In particular, the flow divider 34 is fluidically connected to the anode heat exchanger 32b via the recirculation line 36.

[0058] In the present embodiment, the fuel cell device has a secondary anode heat exchanger 32c. The secondary anode heat exchanger 32c is designed to transfer heat from the cathode exhaust gases flowing from the fuel cell unit 12 or its cathode side 12b, or from the exhaust gases of the afterburner 26, to the fuel, which is supplied to the fuel cell unit 12 or its anode side 12b via the fuel supply line 16. In this way, the efficiency of the fuel cell device 10 can be further increased. In this embodiment, the secondary anode heat exchanger 32c is arranged upstream of the fuel cell unit 12 and downstream of the (primary) anode heat exchanger 32b, relative to the fuel flow direction at the fuel supply line 16.In the exemplary embodiment, the anode heat exchanger 32b is arranged, with respect to the flow direction of the exhaust gas of the afterburner, downstream of the afterburner 26 and upstream of the cathode heat exchanger 32a on the exhaust pipe 28.

[0059] In the exemplary embodiment, the recirculation circuit 38 is designed to return a portion of the anode exhaust gases from the anode side 12b of the fuel cell unit 12. The recirculation circuit 38 has a second mixing section 40b, into which the recirculated fluid is fed into the second fuel supply line 16b, where it is mixed with fresh second fuel. The second fuel supply line 16b and the recirculation line 36 are fluidically connected at the second mixing section 40b. The second mixing section 40b is in Fig. In the embodiment shown in Figure 1, with respect to the flow direction of the second fuel or the second fuel mixed with the recirculated fuel, the second fuel supply line 16b is arranged fluidically downstream of the second fuel source 14b and upstream of the fuel cell unit 12, for example upstream of the first mixing section 40a, at which the first fuel supply line 16a is fluidically connected to the second fuel supply line 16b. The first mixing section 40a is fluidically arranged, with respect to the flow direction of the second fuel or a mixture of the first fuel, the second fuel, and the recirculated fuel, immediately upstream of the (primary) anode heat exchanger 32b.

[0060] In the Fig. In the embodiment shown in Figure 1, the recirculation blower 42 is arranged, by way of example, on the second fuel supply line 16b. With regard to the flow direction of the second fuel or of the second fuel mixed with the recirculated fuel in the second fuel supply line 16b, the recirculation blower 42 is arranged, by way of example, downstream of the second mixing section 40b and upstream of the first mixing section 40a.

[0061] As an example, the condenser heat exchanger 50 is arranged on the second fuel supply line 16b. In this embodiment, the condenser heat exchanger 50 is positioned downstream of the recirculation fan 42 and upstream of the first mixing section 40a with respect to the flow direction of the second fuel or the second fuel mixed with the recirculated fuel. In this way, during operation, the recirculated fuel mixed with the second fuel first flows through the condenser heat exchanger 50, where the water vapor is at least partially condensed. Subsequently, the recirculated fuel flows through the first mixing section 40a, where fresh first fuel – in this case, hydrogen – is added to the mixture of recirculated fuel and second fuel – in this case, natural gas.

[0062] In the Fig. In the embodiment shown in Figure 1, the recirculated fluid in the condenser heat exchanger 50 is cooled by air supplied by a secondary air supply that is independent of the primary air supply via air source 18. For example, the fuel cell device 10 has a secondary air source 18b. The secondary air source 18b is fluidically connected to the condenser heat exchanger 50 via a secondary air supply line 20b. The secondary air source 18b is, for example, designed as an opening for outside air, which includes a filter for coarse particles. The air is discharged from the condenser heat exchanger 50 and from the fuel cell device 10 via an air outlet 68. A secondary air blower 48b is arranged on the secondary air supply line 20b. Fluidically, the secondary air blower 48b is arranged between the secondary air source 18b and the condenser heat exchanger 50.The secondary air blower 48b is advantageous because it is adjustable in terms of airflow strength.

[0063] The adjustable secondary air blower 48b allows, in particular, the adjustment of the airflow through the condenser heat exchanger 50, thus enabling adjustment of the cooling capacity and the heat extracted from the recirculated fluid. Specifically, the condensation temperature can be set using the secondary air blower.

[0064] In the Fig. In the embodiment shown in Figure 1, a condensate drain 58 is connected to the condenser heat exchanger 50, which is designed to remove condensate from the condenser heat exchanger 50. By way of example, the condensate drain 58 connects the condenser heat exchanger 50 fluidically to a condensate outlet 60.

[0065] Fig. Figure 2 shows a schematic sectional view through the filter 100. The filter 100 has a filter element 102. For example, the filter element 102 is designed as the base body of the filter 100. For example, the filter element 102 is designed as a honeycomb structure with a plurality of channels 106 extending along a flow direction 104 of the fluid. In this context, the flow direction 104 is understood to be the direction in which the fluid flows over the filter element 102 during operation of the filter 100. For example, in this embodiment, the flow direction 104 also corresponds to the direction from which the fluid flows out of the filter element 102 during operation of the filter 100.

[0066] In this exemplary embodiment, the fluid is air. For clarity, only four channels 106 are shown as an example; typically, the filter element 102 has anywhere from one to several dozen channels 106 per square centimeter. Accordingly, the four channels 106 shown are not to scale relative to the filter element 102, but are greatly enlarged. This serves to provide a more precise representation of the channels 106. The filter element 102 is porous; in this example, the filter element 102 is made of a zeolite of type MFI or ZSM-5.

[0067] In the exemplary embodiment, the channels 106 each extend from an inlet side 108 of the filter element 102 to an outlet side 114 of the filter element 102. In the sectional view of Fig. 2. The filter element 102 has a largely rectangular cross-section or cut surface. An example is shown in Fig.2 the inlet side 108 the left side of the depicted cross-sectional area of ​​the filter element 102 and the outlet side 114 the opposite right side.

[0068] By way of example, two of the shown channels 106 are configured as inlet channels 106a, and the other two channels 106 are configured as outlet channels 106b. Each inlet channel 106a has a closure 116 at the outlet side 114, which is configured as a plug by way of example. Each outlet channel 106b has a closure 116 at the inlet side 108 by way of example, which is also configured as a plug by way of example. The inlet channels 106a alternate with the outlet channels 106b in a direction perpendicular to the main direction of extension or longitudinal direction of the channels 106, or perpendicular to the flow direction 104. In other words, each of the outlet channels 106b is directly adjacent to one or two inlet channels 106a, and each of the inlet channels 106a is directly adjacent to one or two outlet channels 106b.In other words, at least one inlet channel 106a is arranged between two outlet channels 106b and at least one outlet channel 106b is arranged between two inlet channels 106a.

[0069] In this way, a fluid flowing from an inlet side 108 into the inlet channels 106a must, during operation of the filter, flow through the porous filter element 102 into the adjacent outlet channels 106b, in order to subsequently flow out of the filter element 102 on the outlet side 114. During operation, the flow of the fluid through the filter element 102 between the channels 106 filters the particles out of the fluid due to the porosity of the filter element 102.

[0070] In the exemplary embodiment, a filter layer 112 is arranged in the inlet channels 106a; more precisely, the inner walls of the inlet channels 106a are covered with the filter layer 112. The filter layer 112 contains, for example, barium and strontium as a protective material 110. The protective material 110 is designed, for example, to chemically bind gaseous impurities in the fluid and thus remove them from the fluid. During operation of the filter 100, a fluid flowing from the inlet channels 106a into the filter element 102 therefore also flows through the filter layer 112 and is cleaned of the gaseous impurities.

[0071] Since during operation the fluid primarily flows into the filter element 102 through the inner walls of the inlet channels 106a, the inner walls of the inlet channels 106a are inlet surfaces 118.

Claims

[1] Filter (100) for cleaning a fluid in an electrochemical cell device (10), preferably a fuel cell device (10), wherein the filter (100) has a filter element (102) which is porous and is provided for filtering particles from the fluid, wherein the filter (100) has at least one filter layer (112) which is provided for removing gaseous impurities from the fluid, characterized by , that the filter element (102) is coated with the filter layer (112). [2] Filter (100) according to claim 1, characterized by , that the filter element (102) has an inlet surface (118) with respect to the fluid and the filter layer (112) is arranged on the inlet surface (118) of the filter element (102). [3] Filter (100) according to any one of the preceding claims, characterized by, that the filter element (102) has a plurality of channels (106) which extend from an inlet side (108) of the filter element (102) to an outlet side (114) of the filter element (102), wherein a plurality of inlet channels (106a), which represent a first subset of the channels (106), each have a closure (116) on their respective outlet side (114). [4] Filter (100) according to claim 3, characterized by , that a plurality of outlet channels (106b), which represent a second subset of the channels (106), each have a closure (1ww) on their respective inlet side (108). [5] Filter (100) according to one of claims 3 or 4, characterized by , that each inlet channel (106a) is adjacent to at least one outlet channel (106b). [6] Filter (100) according to any one of claims 3 to 5, characterized by , that the filter layer (112) is arranged at least sectionally in the inlet channels (106a). [7] Filter (100) according to any one of the preceding claims, characterized by , that the filter layer (112) comprises a protective material (110) comprising at least one alkaline earth metal and / or one alkali metal or one alkaline earth metal compound and / or one alkali metal compound, in particular barium or one barium compound and / or strontium or one strontium compound. [8] Filter (100) according to any one of the preceding claims, characterized by , that the filter (100) has a differential pressure sensor which is designed to detect a differential pressure across the filter element (102). [9] Electrochemical cell devices (10), in particular fuel cell devices (10), comprising an electrochemical cell unit (12) and at least one filter (100) according to any one of the preceding claims. [10] Electrochemical cell device (10) according to claim 9, characterized by, that the filter (10) is arranged in an air supply line (20) in the direction of air flow immediately in front of the electrochemical cell unit (12).

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