METHOD FOR REGENERATION OF A FUEL CELL SYSTEM

Description

State of the art

[0001] Fuel cell systems are known from the state of the art, whereby functional units, such as fuel cells, desulfurization units and / or other reactors, must be replaced and / or removed and regenerated at defined intervals.

[0002] From DE 100 40 011 A1, a fuel cell arrangement with a sulfur filter is known, on which a three-way valve is arranged immediately before and after in order to guide a regeneration gas via special supply and discharge lines exclusively through the sulfur filter.

[0003] From DE 101 21 604 A1 a fuel cell arrangement with a sulfur filter is known, on which a switching valve is arranged immediately before and after in order to guide a regeneration gas via special supply and discharge lines exclusively through the sulfur filter.

[0004] From DE 10 2012 201755 A1 a method for regenerating a desulfurization device of a fuel cell system is known, in which a regeneration agent is discharged through a fuel cell of the fuel cell system.

[0005] DE 101 30 776 A1 discloses a fuel cell system comprising at least two sulfur removal devices connected in parallel. For this purpose, switching means are provided via which the sulfur removal devices are or can be connected alternately, at least temporarily, to the fuel supply line.

[0006] From WO 02 / 02208 A1, a regenerable gas desulfurizer for fuel cells is known with two granulate containers, which can be switched alternately into a fuel or a regeneration agent via switches. Disclosure of the invention

[0007] The invention is based on a method for regenerating a fuel cell system, wherein the fuel cell system has at least one regenerable functional unit, wherein the functional unit is at least partially regenerated in an installed state by means of at least one regeneration agent.

[0008] It is proposed that a fuel cell exhaust gas and a regeneration exhaust gas be combined via a fluid valve of the fuel cell system designed as a 3-way valve, or via a first fluid valve designed as a 2-way valve and a second fluid valve of the fuel cell system designed as a 2-way valve, or via precisely one fluid valve of the fuel cell system designed as a 2-way valve, and be discharged via a discharge line. The functional unit is regenerated in an installed state and in particular in at least one method step, in particular during a regeneration process, at least partially, preferably at least largely, and particularly preferably completely, by means of at least one regeneration agent, in particular with the generation of a regeneration exhaust gas. In particular, the functional unit is exposed to, flooded, and / or flushed with the regeneration agent for at least partial regeneration.The expression "at least to a large extent" is to be understood as meaning in particular at least 55%, advantageously at least 65%, preferably at least 75%, particularly preferably at least 85% and particularly advantageously at least 95%.

[0009] In this context, a "fuel cell system" is understood to mean, in particular, a system designed for the generation of electrical and / or thermal energy, particularly in a stationary and / or mobile manner. In particular, the fuel cell system comprises at least one fuel cell unit, which can be designed as a functional unit, particularly one capable of regeneration. In particular, the fuel cell unit is designed at least to convert at least one chemical reaction energy of at least one, advantageously continuously supplied, fuel and at least one oxidizing agent, such as air and / or oxygen, into electrical and / or thermal energy. In particular, the fuel cell unit can comprise precisely one fuel cell and / or preferably a plurality of fuel cells, which can advantageously be arranged in a fuel cell stack.Furthermore, the at least one fuel cell unit is preferably designed as an alkaline fuel cell (AFC), a polymer electrolyte fuel cell (PEMFC), a magnesium-air fuel cell (MAFC), and / or advantageously as a solid oxide fuel cell (SOFC). "Provided" is to be understood in particular as being specially designed and / or equipped. The fact that an object is intended for a specific function is to be understood in particular as meaning that the object fulfills and / or performs this specific function in at least one application and / or operating state. A "fuel" in this context is to be understood in particular as a chemical substance, advantageously natural gas, whose stored chemical energy can be converted into usable energy, in particular into electrical and / or thermal energy, by reaction in the fuel cell unit.In particular, the fuel may comprise additives and / or auxiliary substances, such as odorants and / or sulfur compounds. Furthermore, the fuel cell system may comprise at least one further, advantageously regenerative, functional unit, in particular a conveying unit, such as a blower and / or a pump, a valve unit, a heat exchanger, a reformer unit, a burner unit, such as a protective gas burner and / or an afterburner, a desulfurization unit, such as a cold desulfurization unit and / or a hot desulfurization unit, and / or another reactor.

[0010] Furthermore, the fuel cell system preferably comprises a regeneration unit, which is advantageously formed at least partially in one piece with the functional unit and / or at least one further component of the fuel cell system and is in particular intended to carry out the method for regenerating the fuel cell system and in particular the at least one regenerable functional unit. In particular, the regeneration unit is thus intended to apply the regeneration agent to the functional unit in an installed state, to flood it and / or to flush it, and in particular to regenerate it at least partially, preferably to at least a large extent and particularly preferably completely, by means of the regeneration agent. In particular, the regeneration unit can for this purpose comprise a conveying unit and / or a computing unit.A "computing unit" is understood to mean, in particular, an electrical and / or electronic unit, which in particular has an information input, an information processing unit, and an information output. Advantageously, the computing unit further comprises at least one processor, at least one memory, at least one input and / or output means, at least one operating program, at least one control routine, at least one calculation routine, and / or at least one evaluation routine, in particular for at least partially automatically and / or automatically carrying out the method for regenerating the fuel cell system.In this context, the term "at least partially integrally formed" for an object with another object should be understood in particular to mean that the objects have at least one common component and / or that at least one component of the object and / or the object is connected and / or formed integrally with at least one component of the further object and / or the further object. Preferably, however, all components of the object are formed integrally with at least one component of the further object. In this context, "integral" should be understood in particular to mean at least materially connected and / or formed with one another. The material bond can be created, for example, by an adhesive process, an injection molding process, a welding process, a soldering process, and / or another process. Advantageously, "integral" should be understood to mean formed from one piece and / or in one piece.Preferably, this one piece is made from a single blank, a mass and / or a casting.

[0011] Furthermore, a "regenerating agent" is to be understood in particular as a particularly reactive agent that is supplied to the functional unit, particularly during the regeneration process, and is particularly intended to cause a reaction, preferably an oxidation, in the functional unit, particularly such that the functional unit is at least partially regenerated. The term "regenerating" a functional unit is to be understood in particular as meaning that the functional unit is restored and / or at least one, particularly reactive, functional agent of the functional unit, which is at least partially consumed and / or converted, particularly in a normal operating mode of the fuel cell system in which energy is generated, is at least partially restored and / or reprocessed.Furthermore, an "installed state" of a functional unit should be understood in particular as a state in which the functional unit is fluidly connected to at least one other functional unit and / or at least one other component of the fuel cell system. This configuration can, in particular, improve efficiency, in particular energy efficiency, implementation efficiency, performance efficiency, maintenance efficiency, component efficiency, installation space efficiency, and / or cost efficiency. In particular, the functional unit can advantageously be dimensioned and / or designed to be small, since a reactive capacity of the functional unit is not required over the entire service life of the fuel cell system, but can advantageously be regenerated.In addition, maintenance can be achieved quickly, as the removal and / or replacement of functional units is no longer necessary. Furthermore, costs and / or the required installation space can be reduced.

[0012] The regeneration agent could, for example, be liquid. However, a gas is preferably used as the regeneration agent, which can advantageously improve the reactivity of the regeneration agent. In particular, the regeneration agent is gaseous in this case.

[0013] Furthermore, it is proposed that the regeneration agent comprise oxygen. Preferably, an oxygen-containing gas, and particularly preferably air, is used as the regeneration agent. This can, in particular, trigger an oxidation reaction required for regeneration. Furthermore, costs can be advantageously reduced.

[0014] It is further proposed that at least one fuel, in particular the fuel already mentioned, flows through the functional unit in at least one normal operating mode, in particular the normal operating mode already mentioned. The functional unit could be designed as a fuel cell unit and in particular be provided for converting the fuel into energy. However, the functional unit is preferably arranged fluidically downstream of and / or preferably upstream of the fuel cell unit. The fuel is preferably processed in the functional unit. In this case, the functional unit can advantageously be designed as a reformer unit, as a desulfurization unit and / or as a further reactor. This can in particular improve the functionality of the fuel cell system and / or its power efficiency.

[0015] Furthermore, it is proposed that, in particular for at least partial regeneration of the functional unit and in particular in at least one method step, at least one residue of at least one fuel, in particular of the aforementioned fuel, is oxidized in the functional unit by means of the regeneration agent. The residue can in particular correspond to carbon and / or carbon compounds and can be present, for example, as a deposit in the functional unit. In particular, the residue can also at least partially correspond to an additive and / or auxiliary substance of the fuel, such as an odorant and / or a sulfur compound. This makes it possible, in particular, to achieve advantageous, rapid and / or simple regeneration of the functional unit.

[0016] The functional unit could, for example, be designed as a fuel cell unit, a reformer unit, and / or as an additional reactor. However, according to a particularly preferred embodiment of the invention, it is proposed that the functional unit be designed as a desulfurization unit, and particularly advantageously as a hot desulfurization unit. In this case, the residual material can particularly preferably correspond to zinc sulfide, which is formed in particular during desulfurization of the fuel in the functional unit designed as a desulfurization unit and is preferably oxidized to zinc oxide and sulfur oxide during the regeneration process.In this context, a "desulfurization unit" is understood to mean, in particular, a unit with at least one functional agent, which is intended to reduce a volume and / or molar fraction of sulfur compounds in the fuel below a specified limit and preferably to remove at least a large portion of them from the fuel, preferably by at least one physical and / or chemical adsorption process and / or absorption process. The desulfurization unit is preferably intended to convert sulfur compounds in the fuel with hydrogen into hydrogen sulfide, which then reacts with zinc oxide present in the desulfurization unit to form water and zinc sulfide. In particular, the zinc oxide corresponds to a functional agent of the functional unit designed as a desulfurization unit.In this way, in particular, an advantageous regeneration of a functional unit designed as a desulfurization unit can be achieved.

[0017] Furthermore, it is proposed that the regeneration agent and / or at least one regeneration exhaust gas generated by the regeneration agent, in particular in at least one method step, be passed at least partially through at least one fluid line fluidically connected to a fuel cell unit, in particular the aforementioned fuel cell unit, in particular a fuel supply line, an oxidant supply line, an exhaust line, and / or a recirculation line. In particular, the fuel cell system can comprise the fluid line. This makes it possible, in particular, to provide a fuel cell system that is advantageously space-efficient and / or component-efficient. Furthermore, the number of additionally required components can be advantageously reduced.

[0018] In a preferred embodiment of the invention, it is proposed that the regeneration agent, in particular in at least one method step, is heated by means of at least one heating unit to a regeneration temperature, advantageously at least 450°C and particularly advantageously at least 480°C, preferably before being fed to the functional unit and / or in the functional unit. In particular, the fuel cell system can comprise the heating unit. In particular, the regeneration unit can be provided to control the heating unit. Particularly preferably, the heating unit is integrated into the functional unit, whereby in particular a particularly energy-efficient heating unit can be provided. In particular, the heating unit is provided to heat the regeneration agent to the regeneration temperature before being fed to the functional unit and / or in the functional unit.In this way, in particular, an advantageously rapid and / or simple heating of the regeneration agent can be achieved, in particular independently of operation of the fuel cell system.

[0019] It is further proposed that at least one regeneration exhaust gas generated by the regeneration agent, in particular in at least one method step, is filtered by means of at least one filter unit, advantageously to reduce and / or remove residual substances, in particular dissolved residues and advantageously sulfur compounds. In particular, the fuel cell system can comprise the filter unit. In particular, the filter unit is provided to filter a regeneration exhaust gas generated by the regeneration agent, advantageously to reduce and / or remove residual substances, in particular dissolved residues and advantageously sulfur compounds. This advantageously allows pollutants to be removed from the regeneration exhaust gas before it is removed from the fuel cell system. Furthermore, in particular, an advantageously environmentally friendly fuel cell system can be provided.

[0020] If the functional unit is at least partially regenerated in a regeneration operating mode that differs from a normal operating mode, in particular the aforementioned normal operating mode, regeneration that is independent of operation can be achieved. Furthermore, existing lines and / or components of the fuel cell system can advantageously be used for the regeneration, thereby advantageously minimizing additional costs. Advantageously, at least the fuel cell unit is not operated in the regeneration operating mode, preferably at least in such a way that no fuel is converted in the fuel cell unit and / or no energy is generated by the fuel cell unit.

[0021] In a further embodiment of the invention, it is proposed that at least one regeneration parameter is detected by means of a detection unit, and the functional unit is at least partially regenerated, preferably at least partially automatically and / or automated, if the regeneration parameter lies outside a setpoint interval. In particular, the fuel cell system can comprise the detection unit. In particular, the detection unit is provided to detect at least one regeneration parameter. In particular, the regeneration unit can be provided to control the detection unit and / or to evaluate the regeneration parameter.A "regeneration parameter" is understood to mean, in particular, a parameter that is correlated with an operating parameter of the functional unit, for example, with a quantity of a functional agent of the functional unit and / or a residual fuel accumulated in the functional unit, and / or of the fuel cell unit, such as, for example, a heating efficiency. In particular, it can be determined at least based on the regeneration parameter and in particular by comparing it with the setpoint interval whether a regeneration process, in particular for regenerating the functional unit, should be initiated. Preferably, the regeneration unit can determine at least based on the regeneration parameter and in particular by comparing it with the setpoint interval whether a regeneration process, in particular for regenerating the functional unit, should be initiated.This can in particular prevent damage and / or degeneration of at least one component of the fuel cell system.

[0022] Furthermore, it is proposed that the functional unit be at least partially regenerated at regular intervals, preferably at least partially automatically and / or automated. Alternatively or additionally, regeneration of the functional unit can also be performed during maintenance and / or manually. This can, in particular, ensure consistent operation.

[0023] The method for regenerating the fuel cell system and the fuel cell system are not intended to be limited to the application and embodiment described above. In particular, the method for regenerating the fuel cell system and the fuel cell system may have a number of individual elements, components, and units that differs from the number stated herein to fulfill a functionality described herein. drawing

[0024] Further advantages will become apparent from the following description of the drawings. The drawings illustrate exemplary embodiments of the invention. The drawings, the description, and the claims contain numerous features in combination. Those skilled in the art will also expediently consider the features individually and combine them into useful further combinations.

[0025] They show: Fig. 1 shows a schematically illustrated fuel cell system with a regenerative functional unit, Fig. 2 shows an exemplary flow diagram of a method for regenerating the fuel cell system, Fig. 3 shows a further exemplary embodiment of a fuel cell system with a regenerative functional unit, Fig. 4 shows a further exemplary embodiment of a fuel cell system with a regenerative functional unit, Fig. 5 shows a further exemplary embodiment of a fuel cell system with a regenerative functional unit, Fig. 6 shows a further exemplary embodiment of a fuel cell system with a regenerative functional unit, Fig. 7 shows a further exemplary embodiment of a fuel cell system with a regenerative functional unit, Fig. 8 shows a further exemplary embodiment of a fuel cell system with a regenerative functional unit, Fig.Fig. 9 shows a further embodiment of a fuel cell system with a regenerative functional unit, Fig. 10 shows a further embodiment of a fuel cell system with a regenerative functional unit, Fig. 11 shows a further embodiment of a fuel cell system with a regenerative functional unit, Fig. 12 shows a further embodiment of a fuel cell system with a regenerative functional unit and Fig. 13 shows a further embodiment of a fuel cell system with a regenerative functional unit. Description of the embodiments

[0026] Figure 1shows, purely schematically, an exemplary fuel cell system 10a, particularly illustrated as a black box, not according to the invention. The fuel cell system 10a is designed as a system for generating and / or providing electrical and / or thermal energy. The fuel cell system 10a is used, for example, in buildings, in particular for generating electrical energy and / or for heating purposes and / or for hot water production.

[0027] The fuel cell system 10a has a housing 34a. The housing 34a is designed as an outer housing. The housing 34a is designed as a receiving housing. The housing 34a is designed as a closed housing. The housing 34a is thermally insulated. The housing 34a is designed, for example, as a hot box. Alternatively, it is conceivable to dispense with a housing entirely.

[0028] The fuel cell system 10a comprises a plurality of supply lines 36a, 38a, 40a. The supply lines 36a, 38a, 40a are connected to the housing 34a. A first supply line 36a of the supply lines 36a, 38a, 40a serves to supply a fuel 16a, in this case, in particular natural gas. A second supply line 38a of the supply lines 36a, 38a, 40a serves to supply an oxidizing agent 42a, in this case, in particular air. A third supply line 40a of the supply lines 36a, 38a, 40a serves to supply a regeneration agent 14a, in this case, in particular an oxygen-containing gas, in particular air. Alternatively, it is conceivable to dispense with at least one supply line and to supply an oxidizing agent and a regeneration agent, for example, through a single supply line. In addition, a fuel cell system could have additional supply lines, for example for water.

[0029] In addition, the fuel cell system 10a comprises a plurality of discharge lines 44a, 46a, 48a. The discharge lines 44a, 46a, 48a are connected to the housing 34a. A first discharge line 44a of the discharge lines 44a, 46a, 48a is designed as an electrical line and serves to utilize electrical energy 50a generated by the fuel cell system 10a. A second discharge line 46a of the discharge lines 44a, 46a, 48a serves to discharge a fuel cell exhaust gas 52a, which is generated in particular during energy generation. A third discharge line 48a of the discharge lines 44a, 46a, 48a serves to discharge a regeneration exhaust gas 18a, which is generated in particular by the regeneration agent 14a. Alternatively, it is conceivable to dispense with at least one discharge line and to discharge a fuel cell exhaust gas and a regeneration exhaust gas, for example, through a single discharge line.In addition, a fuel cell system could have additional discharge lines, for example for water, in particular a heat recovery system.

[0030] Furthermore, the fuel cell system 10a has a plurality of functional units 11a, 12a, 13a. The functional units 11a, 12a, 13a are arranged within the housing 34a. In a normal operating mode, at least the fuel 16a flows through the functional units 11a, 12a, 13a. At least one of the functional units 11a, 12a, 13a is further configured as a regenerative functional unit.

[0031] A first functional unit 11a of the functional units 11a, 12a, 13a is designed as a fuel cell unit 24a. The fuel cell unit 24a is shown here in simplified form as a single fuel cell. In the present case, the fuel cell unit 24a is designed as a solid oxide fuel cell (SOFC). The fuel cell unit 24a is intended to be operated with the fuel 16a and / or a fuel mixture and the oxidant 42a. The fuel cell unit 24a is intended to convert at least the fuel 16a using an electrochemical process and, in particular, to generate the electrical energy 50a. To supply the fuel 16a and / or the oxidant 42a, the fuel cell unit 24a is fluidly connected to the first supply line 36a and / or the second supply line 38a by means of at least one fluid line 20a of the fuel cell system 10a.In addition, the fuel cell unit 24a is fluidly connected to the second discharge line 46a by means of at least one further fluid line 22a of the fuel cell system 10a for discharging the fuel cell exhaust gas 52a. Alternatively, a fuel cell unit could also comprise a plurality of fuel cells. Furthermore, a fuel cell unit could alternatively also be designed as an alkaline fuel cell (AFC), a polymer electrolyte fuel cell (PEMFC), and / or a magnesium-air fuel cell (MAFC).

[0032] A second functional unit 12a of the functional units 11a, 12a, 13a is designed as a desulfurization unit. In the present case, the second functional unit 12a is designed, for example, as a hot desulfurization unit. The second functional unit 12a has an operative connection to the first functional unit 11a, in particular the fuel cell unit 24a. The second functional unit 12a is fluidically arranged upstream of the first functional unit 11a, in particular the fuel cell unit 24a. The second functional unit 12a is designed to be regenerative. The second functional unit 12a is provided for processing the fuel 16a. The second functional unit 12a is provided for removing sulfur compounds from the fuel 16a.In the present case, the second functional unit 12a is designed to convert sulfur compounds in the fuel 16a with hydrogen into hydrogen sulfide, which then reacts with zinc oxide to form water and zinc sulfide. The zinc oxide corresponds to a functional agent of the second functional unit 12a and is at least partially consumed, particularly in normal operating mode. Alternatively, however, a second functional unit could also be designed as a cold desulfurization unit and / or comprise a functional agent other than zinc oxide. Furthermore, it is conceivable to design a second functional unit so that it is not capable of regeneration.

[0033] Further functional units 13a, which are not shown in detail in the present case, can be designed, for example, as a reformer unit, as a burner unit and / or as further reactors or the like and can advantageously be designed to be at least partially regenerable.

[0034] The fuel cell system 10a further comprises at least one heating unit 26a. The heating unit 26a is arranged within the housing 34a. The heating unit 26a has an operative connection with the second functional unit 12a, which is designed in particular as a desulfurization unit. In the present case, the heating unit 26a is integrated into the second functional unit 12a. The heating unit 26a is provided for heating the regeneration agent 14a. Alternatively, it is conceivable to arrange a heating unit outside a second functional unit. In this case, the heating unit is advantageously arranged fluidically upstream of the second functional unit. In principle, however, a heating unit could also be dispensed with entirely. In this case, it is conceivable, for example, to use heat and / or waste heat generated in a normal operating mode from a fuel cell system and / or a fuel cell unit to heat a regeneration agent.

[0035] In addition, the fuel cell system 10a comprises at least one filter unit 28a. The filter unit 28a is arranged within the housing 34a. The filter unit 28a has an operative connection with the second functional unit 12a, which is designed in particular as a desulfurization unit. The filter unit 28a is arranged fluidically downstream of the second functional unit 12a. The filter unit 28a is arranged fluidically between the second functional unit 12a and the third discharge line 48a. The filter unit 28a is provided for filtering the regeneration exhaust gas 18a generated by the regeneration agent 14a. In the present case, the filter unit 28a is provided for reducing and / or removing sulfur compounds in the regeneration exhaust gas 18a, in particular those dissolved during a regeneration process.Alternatively or additionally, a filter unit could also be provided to filter carbon compounds or other pollutants, particularly those released during a regeneration process. Furthermore, in principle, a filter unit could be dispensed with entirely.

[0036] Furthermore, the fuel cell system 10a comprises at least one detection unit 30a. The detection unit 30a is arranged within the housing 34a. The detection unit 30a has an operative connection with the second functional unit 12a, which is designed in particular as a desulfurization unit. In the present case, the detection unit 30a is integrated, for example, into the second functional unit 12a. The detection unit 30a is provided to detect at least one regeneration parameter, based on which, in particular by comparison with a setpoint interval, it can be determined whether a regeneration process should be initiated, in the present case in particular for the regeneration of the second functional unit 12a. In the present case, the regeneration parameter is correlated with an operating parameter of the second functional unit 12a, for example, with a residual amount of the functional agent of the second functional unit 12a.Alternatively, it is conceivable to arrange a detection unit outside a second functional unit. It is also conceivable to integrate a detection unit into a fuel cell unit. A detection unit could also be provided to measure heating efficiency or the like. In principle, however, a detection unit could be dispensed with entirely, for example, if a regeneration process is carried out at regular intervals.

[0037] Furthermore, the fuel cell system 10a comprises a regeneration unit 32a. The regeneration unit 32a is provided to carry out a method for regenerating the fuel cell system 10a and, in the present case, in particular the second functional unit 12a. The regeneration unit 32a is thus provided to apply the regeneration agent 14a to the second functional unit 12a in an installed state, to flood it, and / or to flush it, and to at least partially regenerate it by means of the regeneration agent 14a. Alternatively, however, a regeneration unit could also be provided for the at least partial regeneration of a first functional unit, in particular designed as a fuel cell unit, and / or a further functional unit, in particular designed as a reformer unit, as a burner unit, and / or as further reactors or the like.

[0038] Figure 2shows an exemplary flow chart of the method for regenerating the fuel cell system 10a.

[0039] A step 60a corresponds to a normal operating mode. In the normal operating mode, energy is generated by the fuel cell unit 24a. In order to prevent damage to the components of the fuel cell system 10a, such as reformer units containing nickel and / or precious metals and / or an anode of the fuel cell unit 24a, by the fuel 16a and in particular additives and / or auxiliary substances present in the fuel 16a, such as odorants and / or sulfur compounds, the fuel 16a is processed by at least some of the functional units 12a, 13a. In the present case, the fuel 16a is processed, in particular desulfurized, at least in the second functional unit 12a, with the fuel 16a flowing through the second functional unit 12a.In the second functional unit 12a, sulfur compounds in the fuel 16a are converted with hydrogen into hydrogen sulfide, which then reacts with zinc oxide to form water and zinc sulfide. The zinc oxide, which corresponds to the functional agent of the second functional unit 12a, is at least partially consumed in the process. Furthermore, residues of the fuel 16a accumulate in the second functional unit 12a. In this case, the residues correspond to the zinc sulfide produced during desulfurization. In order to achieve sufficient desulfurization over the entire service life of the fuel cell system 10a, the second functional unit 12a must be replaced or, as in the present case, regenerated, whereby, in particular, the functional agent of the second functional unit 12a is restored.

[0040] A step 62a corresponds to a detection process, which can take place in particular at regular intervals and / or continuously during normal operating mode and / or in a special detection operating mode. The regeneration parameter is detected by means of the detection unit 30a and compared with a target value interval. If the regeneration parameter lies outside the target value interval, a regeneration process is initiated, preferably at least partially automatically and / or automatically. Alternatively, however, a warning message could also be issued so that a regeneration process can be started during maintenance. In principle, a detection process could also be dispensed with. In this case, it is conceivable to at least partially regenerate a second functional unit or other functional units at regular intervals, for example once a week, once a month and / or once a year.

[0041] If the regeneration parameter lies outside the setpoint interval, step 64a follows. In step 64a, the normal operating mode is terminated. The fuel cell system 10a and / or at least the fuel cell unit 24a are shut down. Furthermore, valves can be used to block the inflow of fuel 16a and / or the oxidizing agent 42a. A regeneration operating mode different from the normal operating mode is then started. For this purpose, it may be necessary to install the filter unit 28a into the fuel cell system 10a, for example, in the form of a replaceable filter cartridge. Preferably, however, the filter unit 28a is permanently integrated into the fuel cell system 10a. Furthermore, it is conceivable not to shut down the fuel cell system 10a completely.In particular, the regeneration process and / or the regeneration operating mode can be started in a hot state, for example after a rapid shutdown of the fuel cell unit 24a, whereby the fuel cell system 10a can advantageously be restarted quickly and / or the heating unit 26a can be completely dispensed with.

[0042] A step 66a corresponds to the regeneration operating mode and / or a regeneration process. In this case, the second functional unit 12a is at least partially regenerated in the installed state using the regeneration agent 14a. In the present case, the second functional unit 12a is at least partially regenerated at regular intervals, which advantageously allows the second functional unit 12a to be dimensioned and / or designed to be small, since a reactive capacity of the second functional unit 12a is not required over the entire operating period of the fuel cell system 10a.

[0043] For this purpose, the regeneration agent 14a, in this case in particular an oxygen-containing gas, flows through the third supply line 40a into the housing 34a. The regeneration agent 14a is then conducted at least partially through the fluid line 20a and / or the further fluid line 22a to the second functional unit 12a, which advantageously makes additional fluid lines unnecessary. In particular, a flow path of the regeneration agent 14a is adjusted, for example by means of valves, such that components, such as a recirculation fan, which could be damaged by the regeneration agent 14a, are omitted and / or are not flowed through by the regeneration agent 14a. The second functional unit 12a is then subjected to, flooded, and / or flushed with the regeneration agent 14a for at least partial regeneration.

[0044] In the second functional unit 12a, the regeneration agent 14a is then heated by the heating unit 26a to a regeneration temperature, in this case in particular at least 480°C, so that the residual materials of the fuel 16a, in this case in particular zinc sulfide, are oxidized in the second functional unit 12a. In this case, the zinc sulfide oxidizes to zinc oxide and sulfur dioxide. The resulting zinc oxide remains as a new functional agent in the second functional unit 12a. The sulfur dioxide corresponds to the regeneration exhaust gas 18a.

[0045] The regeneration exhaust gas 18a is then conducted, at least in sections, through the fluid line 20a and / or the further fluid line 22a to the third discharge line 48a. In particular, a flow path of the regeneration exhaust gas 18a is adjusted, for example by means of valves, such that components, such as an anode of the fuel cell unit 24a and / or a recirculation fan, which can be damaged by the regeneration exhaust gas 18a, are excluded and / or are not flowed through by the regeneration exhaust gas 18a. Before the regeneration exhaust gas 18a is discharged from the fuel cell system 10a, the regeneration exhaust gas 18a is additionally filtered by the filter unit 28a, whereby sulfur compounds can be advantageously removed from the regeneration exhaust gas 18a.

[0046] The example flow chart in Figure 2In particular, this is intended to describe, merely by way of example, a method for regenerating a fuel cell system. In particular, individual steps and / or a sequence of steps can vary. In particular, it is also conceivable to dispense with a detection process. Furthermore, it is conceivable to at least partially regenerate a fuel cell unit, a reformer unit, and / or another reactor in addition to or as an alternative to a desulfurization unit.

[0047] In the Figures 3 to 13Further embodiments of fuel cell systems according to the invention and not according to the invention are shown. The following descriptions and the drawings are essentially limited to the differences between the embodiments, whereby with regard to components with the same designation, in particular with regard to components with the same reference numerals, reference is also made to the drawings and / or the description of the other embodiments, in particular the Figures 1 and 2 To distinguish the embodiments, the letter a is added to the reference numerals of the embodiment in the Figures 1 and 2 In the examples of the Figures 3 to 13 the letter a is replaced by the letters b to I.

[0048] In Figure 3 A particularly detailed embodiment of the invention is shown. The embodiment of the Figure 3 is followed by the letter b.

[0049] Figure 3 shows a fuel cell system 10b with a fuel cell unit 24b in a regeneration mode. Valves opened in the regeneration mode are in Figure 3 aligned parallel to a flow direction, particularly indicated by arrows, while closed valves are aligned perpendicular to the flow direction.

[0050] In the present case, the fuel cell system 10b comprises two supply lines 36b, 38b, 40b. A first supply line 36b of the supply lines 36b, 38b, 40b serves to supply a fuel 16b. A second supply line 38b, 40b of the supply lines 36b, 38b, 40b serves to supply an oxidizing agent 42b and a regeneration agent 14b. To convey the regeneration agent 14b, a fan 56b of the fuel cell system 10b is operated in the regeneration mode.

[0051] In addition, the fuel cell system 10b includes a discharge line 46b, 48b, which serves to discharge a fuel cell exhaust gas 52b and a regeneration exhaust gas 18b. The fuel cell exhaust gas 52b and the regeneration exhaust gas 18b are combined via a fluid valve 54b of the fuel cell system 10b, designed as a 3-way valve. Furthermore, a flow path of the regeneration exhaust gas 18b is selected such that the fuel cell unit 24b is left unattended and / or is not flowed through by the regeneration exhaust gas 18b.

[0052] In addition, a regenerative functional unit 12b is designed as a desulfurization unit.

[0053] In the regeneration operating mode, the regeneration agent 14b, in this case in particular air, flows through a cathode of the fuel cell unit 24b, via a functional unit 13b designed as a burner unit, and then through two fuel valves of the fuel cell system 10b and a fluid line 20b, designed in particular as a fuel supply line, into the functional unit 12b. In principle, however, the regeneration agent 14b could also flow through an anode of the fuel cell unit 24b and via a recirculation path. After the regeneration of the functional unit 12b, the regeneration exhaust gas 18b generated by the regeneration agent 14b flows through a regeneration exhaust gas line 58b into a further fluid line 22b, designed in particular as an exhaust gas line, which is connected to the discharge line 46b, 48b.

[0054] The Figures 4 to 7 show alternative designs to the one in Figure 3illustrated embodiment and in particular for guiding a regeneration exhaust gas.

[0055] In Figure 4 A further embodiment of the invention is shown. The embodiment of the Figure 4 The letter c is added after the letter. The further embodiment of the Figure 4 differs from the previous embodiments at least essentially by guiding a regeneration exhaust gas 18c.

[0056] In this case, a fuel cell exhaust gas 52c and the regeneration exhaust gas 18c are combined via a first fluid valve 54c designed as a 2-way valve and a second fluid valve 55c designed as a 2-way valve of a fuel cell system 10c and are discharged by means of a discharge line 46c, 48c.

[0057] In Figure 5 A further embodiment of the invention is shown. The embodiment of the Figure 5 is followed by the letter d. The further embodiment of the Figure 5 differs from the previous embodiments at least essentially by guiding a regeneration exhaust gas 18d.

[0058] In this case, a fuel cell exhaust gas 52d and the regeneration exhaust gas 18d are combined via exactly one fluid valve 54d of a fuel cell system 10d, designed as a 2-way valve, and are discharged by means of a discharge line 46d, 48d.

[0059] In Figure 6 An embodiment of a fuel cell system 10e is shown which is not according to the invention. The embodiment of the Figure 6 is followed by the letter e. The further embodiment of the Figure 6 differs from the previous embodiments at least essentially by guiding a regeneration exhaust gas 18e.

[0060] In this case, a fuel cell exhaust gas 52e and the regeneration exhaust gas 18e are not combined, but are discharged via separate lines 46e, 48e of the fuel cell system 10e.

[0061] In Figure 7 Another embodiment of a fuel cell system 10f is shown. The embodiment of the Figure 7 The letter f is added after the letter. The further embodiment of the Figure 7 differs from the previous embodiments at least essentially by a routing of a regeneration exhaust gas 18f.

[0062] In this case, a fuel cell exhaust gas 52f and the regeneration exhaust gas 18f are not combined, but are discharged via separate lines 46f, 48f of the fuel cell system 10f.

[0063] In addition, the fuel cell system 10f comprises a fluid valve 55f designed as a 2-way valve which serves to close a second discharge line 46f.

[0064] In Figure 8 A further embodiment of the invention is shown. The embodiment of the Figure 8 The letter g is added after the letter. The further embodiment of the Figure 8 differs from the previous embodiments at least essentially by a number of functional units 11g, 12g, 13g of a fuel cell system 10g and / or by an anode exhaust gas recirculation.

[0065] In the present case, the fuel cell system 10g comprises a first functional unit 11g, which is designed as a fuel cell unit 24g. Furthermore, the fuel cell system 10g comprises two separately formed, regenerative functional units 12g, which are designed as reactors. Furthermore, the fuel cell system 10g comprises several further functional units 13g, such as several heat exchangers.

[0066] In Figure 9 A further embodiment of a fuel cell system 10h is shown, not according to the invention. The embodiment of the Figure 9 The letter h is added after the letter. The further embodiment of the Figure 9 differs from the previous embodiments at least essentially by guiding a regeneration agent 14h and / or a regeneration exhaust gas 18h.

[0067] In the present case, the fuel cell system 10h comprises a regenerative functional unit 12h and a fuel cell unit 24h.

[0068] Furthermore, a first supply line 36h of the fuel cell system 10h serves to supply a fuel 16h.

[0069] A second supply line 38h of the fuel cell system 10h is formed integrally with a third discharge line 48h of the fuel cell system 10h and serves in at least one operating state to supply an oxidizing agent 42h and in at least one further operating state to discharge the regeneration exhaust gas 18h.

[0070] A third supply line 40h of the fuel cell system 10h is formed integrally with a second discharge line 46h of the fuel cell system 10h and serves in at least one operating state to supply the regeneration agent 14h and in at least one further operating state to discharge a fuel cell exhaust gas 52h.

[0071] In addition, the fuel cell system 10h comprises two additional fluid valves 54h, 55h for conveying the oxidant 42h and / or the regeneration exhaust gas 18h, which in the present case are shown as 3-way valves, but which in principle can also be designed as 2-way valves.

[0072] In the regeneration operating mode, the regeneration agent 14h, in this case in particular air, is sucked into the functional unit 12h by means of a fan 56h through the third supply line 40h and / or the second discharge line 46h via a functional unit 13h designed as a burner unit and then through a fluid line 20h, designed in particular as a fuel supply line. After the regeneration of the functional unit 12h, the regeneration exhaust gas 18h generated by the regeneration agent 14h flows through a regeneration exhaust gas line 58h and through the second supply line 38h and / or the third discharge line 48h out of the fuel cell system 10h.

[0073] The Figure 10 shows an alternative embodiment not according to the invention to that in Figure 9 illustrated embodiment and in particular for guiding a regeneration exhaust gas.

[0074] The embodiment of the Figure 10The letter i is placed after the letter. The further embodiment of the Figure 10 differs from the previous embodiments at least essentially by routing a regeneration exhaust gas 18i.

[0075] In this case, a second supply line 38i of a fuel cell system 10i is formed separately from a third discharge line 48i of the fuel cell system 10i. An oxidizing agent 42i and the regeneration exhaust gas 18i are supplied to and discharged from the fuel cell system 10i via separate lines, in particular the second supply line 38i and the third discharge line 48i.

[0076] In Figure 11 A further non-inventive embodiment of a fuel cell system 10j is shown. The embodiment of the Figure 11 The letter j is added after the letter. The further embodiment of the Figure 11differs from the previous embodiments at least essentially by a number of functional units 11j, 12j, 13j of the fuel cell system 10j.

[0077] In the present case, the fuel cell system 10j comprises a first functional unit 11j, which is designed as a fuel cell unit 24j. Furthermore, the fuel cell system 10j comprises two separately formed, regenerative functional units 12j, which are designed as reactors. Furthermore, the fuel cell system 10j comprises several further functional units 13j, such as several heat exchangers.

[0078] In Figure 12 A further embodiment of a fuel cell system 10k is shown, not according to the invention. The embodiment of the Figure 12 The letter k is added after the letter. The further embodiment of the Figure 12differs from the previous embodiments at least essentially by a routing of a regeneration exhaust gas 18k.

[0079] In the present case, the fuel cell system 10k comprises a regenerative functional unit 12k and a fuel cell unit 24k.

[0080] Furthermore, a first supply line 36k of the fuel cell system 10k serves to supply a fuel 16k.

[0081] A second supply line 38k of the fuel cell system 10k is at least partially formed integrally with a third supply line 40k of the fuel cell system 10k and serves in at least one operating state to supply an oxidizing agent 42k and in at least one further operating state to supply a regeneration agent 14k.

[0082] A second discharge line 46k of the fuel cell system 10k is at least partially formed integrally with the third supply line 40k and serves in at least one operating state to discharge a fuel cell exhaust gas 52k and in at least one further operating state to supply the regeneration agent 14k.

[0083] Furthermore, a third discharge line 48k of the fuel cell system 10k serves to discharge the regeneration exhaust gas 18k.

[0084] In addition, the fuel cell system 10k includes an additional blower 56k designed as a regeneration blower for conveying the regeneration exhaust gas 18k. The blower 56k is permanently integrated into the fuel cell system 10k and / or can be integrated into the fuel cell system 10k during maintenance. In particular, the blower 56k can be supported and / or relieved by additional blowers, such as an oxidizer blower and / or a recirculation blower.

[0085] In the regeneration operating mode, the regeneration agent 14k, in this case in particular air, is conveyed through the third supply line 40k and via a functional unit 13k designed as a burner unit or via a cathode of the fuel cell unit 24k and the functional unit 13k designed as a burner unit and then through a fluid line 20k, designed in particular as a fuel supply line, into the functional unit 12k. After the regeneration of the functional unit 12k, the regeneration exhaust gas 18k generated by the regeneration agent 14k is conveyed by the blower 56k through a regeneration exhaust gas line 58k and through the third discharge line 48k out of the fuel cell system 10k.

[0086] In Figure 13 A further embodiment of a fuel cell system 10l is shown, not according to the invention. The embodiment of the Figure 13The letter l is added after the letter. The further embodiment of the Figure 13 differs from the previous embodiments at least essentially by a number of functional units 11l, 12l, 13l of the fuel cell system 10l.

[0087] In the present case, the fuel cell system 10l comprises a first functional unit 111, which is designed as a fuel cell unit 24l. Furthermore, the fuel cell system 10l comprises two separately formed, regenerative functional units 12l, which are designed as reactors. Furthermore, the fuel cell system 10l comprises several further functional units 13l, such as several heat exchangers.

Claims

1. Method for regenerating a fuel cell system (10b; 10c; 10d), wherein the fuel cell system (10b; 10c; 10d; 10g) has at least one functional unit (12b; 12g) capable of regeneration, wherein the functional unit (12b; 12g), in an installed state, is at least partially regenerated by means of at least one regeneration agent (14b), characterized in that a fuel cell exhaust gas (52b; 52c; 52d) and a regeneration exhaust gas (18b; 18c; 18d) are combined via a fluid valve (54b) of the fuel cell system (10b) designed as a 3-way valve or via a first fluid valve (54c) designed as a 2-way valve and a second fluid valve (55c) of the fuel cell system (10c) designed as a 2-way valve or via precisely one fluid valve (54d) of the fuel cell system (10d) designed as a 2-way valve and are discharged by means of a discharge line (46b, 48b; 46c, 48c; 46d, 48d).

2. Method according to Claim 1, characterized in that a gas is used as the regeneration agent (14b).

3. Method according to Claim 1 or 2, characterized in that the regeneration agent (14b) comprises oxygen.

4. Method according to any of the preceding claims, characterized in that at least one fuel (16b) flows through the functional unit (12b; 12g) in at least one normal operating mode.

5. Method according to Claim 4, characterized in that the fuel (16b) is treated in the functional unit (12b; 12g).

6. Method according to any of the preceding claims, characterized in that at least one residual substance of at least one fuel (16b) is oxidized in the functional unit (12b; 12g) by means of the regeneration agent (14b).

7. Method according to any of the preceding claims, characterized in that the functional unit (12b; 12g) is designed as a desulfurization unit.

8. Method according to any of the preceding claims, characterized in that the regeneration agent (14b) and / or at least one regeneration exhaust gas (18b; 18c; 18d) produced by the regeneration agent (14b) is conducted at least in portions by at least one fluid line (20b, 22b) fluidically connected to a fuel cell unit (24b).

9. Method according to any of the preceding claims, characterized in that the regeneration agent (14b) is heated to a regeneration temperature by means of at least one heating unit.

10. Method according to any of the preceding claims, characterized in that at least one regeneration exhaust gas (18b; 18c; 18d) produced by the regeneration agent (14b) is filtered by means of at least one filter unit.

11. Method according to any of the preceding claims, characterized in that the functional unit (12b; 12g) is at least partially regenerated in a regeneration operating mode different from a normal operating mode.

12. Method according to any of the preceding claims, characterized in that at least one regeneration characteristic variable is detected by means of a detection unit and the functional unit (12b; 12g) is at least partially regenerated if the regeneration characteristic variable lies outside a setpoint value interval.

13. Method according to any of the preceding claims, characterized in that the functional unit (12b; 12g) is at least partially regenerated at regular time intervals.

14. Fuel cell system (10b; 10c; 10d; 10g) for executing the method according to any of Claims 1-13 having at least one functional unit (12b; 12g) capable of regeneration and having a regeneration unit, which is provided for executing a method for regenerating the fuel cell system (10b; 10c; 10d; 10g), in which the functional unit (12b; 12g), in an installed state, is at least partially regenerated by means of at least one regeneration agent (14b), wherein the regeneration unit is intended to act on, flood and / or flush the functional unit (12b; 12g), in an installed state, with the regeneration agent (14b) and to regenerate at least a large portion of the functional unit, characterized by a discharge line (46b, 48b; 46c, 48c; 46d, 48d), which is used to discharge a fuel cell exhaust gas (52b; 52c; 52d) and a regeneration exhaust gas (18b; 18c; 18d).