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    • 专利摘要:
    The invention relates to a method for operating a fuel cell system (1) with a fuel (27), which fuel cell system (1) at least one high temperature fuel cell (1.0) having at least one arranged in a cathode space (12) cathode (11), with at least one in a Anodes (13) arranged anode space (14) and with a between cathode space (12) and anode space (14) existing electrolyte (15), wherein in an anode gas circulation (20) from the anode space (14) of at least one high-temperature fuel cell (10) recycled Anode exhaust gas (25) is mixed with fuel (27) and fed as Anodenzugas (30) with at least one gas conveyor (50) to an anode gas heat exchanger (70), in which the anode gas (31) is thermostated, wherein further in at least one reforming unit (60, 61) in the anode gas circuit (20) of the fuel (27) is reformed. The at least one reforming unit (60, 61, 62, 63) is located in a hot circulation section (210) of the anode gas loop (20) in which an anode gas temperature (200) is above the equilibrium temperature required in the reforming unit (60, 61, 62, 63) is reached and the at least one gas conveying device (50) in a cool circuit section (220) of the anode gas circulation (20) is arranged, in which an anode gas temperature (200) below thatn hot circuit section (210) is reached;
    公开号:AT518012A1
    申请号:T765/2015
    申请日:2015-11-26
    公开日:2017-06-15
    发明作者:Ing Dr Martin Hauth Dipl；Dipl Ing Rechberger Jürgen
    申请人:Avl List Gmbh；
    IPC主号:
    专利说明:

    Apparatus and method for operating a fuel cell system
    The invention relates to a method for operating a fuel cell system with a fuel, which fuel cell system at least one
    High-temperature fuel cell having at least one disposed in a cathode chamber cathode, comprising at least one arranged in an anode compartment and an anode electrolyte between Kathpdenraum and anode space, wherein in an anode gas circulation from the anode space of the at least one HoGhtemperaturbrennstoffzelle recirculated anode exhaust gas mixed with fuel and this mixture as Änodenzugas with at least one gas delivery device is fed to an anode gas heat exchanger in which the Anodes gas is thermostated, wherein further in at least one reforming unit in the Anodengaskreislauf the fuel is reformed. Likewise, devices for operating a fuel cell system with a fuel are specified in the context of the invention.
    By a high-temperature fuel cell, the person skilled in the art will understand, for example, a Molten Carbonate Fuel Cell (MCFG) which operates at operating temperatures of approximately from 580 ° C to 6759 ° C. The electrolyte used in this type of fuel cell is usually an alkali metal carbonate melt of lithium and potassium carbonate. Similarly, solid oxide fuel cells (Solid Oxide Fuel Gell, SOFG) are high temperature fuel cells. Solid oxide fuel cells are operated at operating temperatures of about 650 ° C to 10OCTC.
    The electrolyte of this cell type consists of a solid ceramic material capable of conducting oxygen ions but insulating for electrons. On both sides of the electrolyte layer are the electrodes, cathode and anode. They are gas-permeable electrical conductors. The oxygen-ion-conducting electrolyte is provided, for example, as a thin membrane in order to be able to transport the oxygen ions with low energy, which, however, only works at the aforementioned high temperatures. The remote from the electrolyte, the outer side of the cathode is surrounded by air, the outer anode side of fuel gas. Unused air and unused fuel gas and combustion products are extracted.
    Fuel cell systems, which are used in particular as auxiliary power supply devices in motor vehicles or as stationary systems or "stationary power plants", and which usually comprise at least one fuel cell for generating electric current from cathode air and reformate gas, are already known from the prior art. Such a fuel cell is usually composed of a plurality of individual fuel cell elements, which are stacked on each other and are referred to as a fuel cell stack.
    For producing reformate gas, such fuel cell systems are equipped with a reformer which generates the reformate gas from a fuel, usually a hydrocarbon such as diesel or natural gas * and from reformer air and / or water vapor. The reformate gas then contains hydrogen gas and carbon monoxide. The fuel cell system can also be equipped with an air supply device which sucks in ambient air by means of an air conveyor from an environment of the fuel cell system and subdivides these, for example, into reformer air and cathode air. The reformer air can then be supplied to the reformer via a reformer air line, while the cathode air can be supplied via a cathode air line to a cathode side of the at least one fuel cell. Usually, in such a fuel cell system, it is provided to guide anode gas of an anode side of the at least one fuel cell in the direction of the reformer by means of a recirculation line so as to be able to recycle anode exhaust gas from the respective fuel cell to the reformer. For driving the anode exhaust gas is usually in the recirculation line
    Gas conveyor arranged to convey hot anode exhaust gas, which usually a recirculation pump or an anode gas blower is used.
    Furthermore, various variants of the fuel supply to the anode of a fuel cell are already known. Usually, the gas delivery device is arranged in an anode gas circulation upstream of the reformer. Thus, the anode gas, ie the mixture of recirculated anode exhaust gas and fed fuel, is further mixed in the gas delivery device and supplied from the latter to the downstream reformer. It is necessary, high
    Anodeoeintrittstemperaturen to achieve in the fuel cell or in a
    Fuel cell stack to prevent the formation of thermal stresses. Conversely, in the gas conveying device required for the recirculation of the anode gas, it should be noted that the inlet temperature of the anode gas into the gas conveying device does not become too high to prevent damage and to ensure proper operation of the gas conveying device.
    A disadvantage of the previously known fuel cell systems, therefore, that cooled for safe operation of the gas conveyor hot anode gas or the gas conveyor must be cooled separately and thus the anode gas, which is mixed with a fuel and fed to the reformer as Anodenzugas too cold for Reforming is. Why the anode gas must be reheated before the reformer or the reformer must be heated with an external heater, which is complicated and energetically unfavorable.
    It is therefore the object of the present invention to provide a method for operating a fuel cell system with a fuel, which avoids the described disadvantages of the prior art and in which a proper and energetically optimized operation of the fuel cell system is ensured. It is a further object of the present invention to provide corresponding devices for operating such a fuel cell system with a fuel.
    The first object of the invention relates to a method for operating a generic fuel cell system with a fuel which fuel cell system comprises at least one high-temperature fuel cell with at least one arranged in a cathode compartment cathode, at least one arranged in an anode compartment anode and a space between the cathode compartment and anode vorh andenen electrolyte wherein mixed in an anode gas cycle from the anode space of the at least one high-temperature fuel cell recirculated anode exhaust gas with fuel and is supplied as Anodenzugas with at least one gas conveyor an anode gas heat exchanger in which the anode gas is thermostated, wherein further reformed in at least one reforming unit in the Anodengaskreislauf the fuel is solved by arranging the at least one reforming unit in a hot cycle section of the anode gas cycle It is in which hot cycle section in fuel cell operation an anode gas temperature above the equilibrium temperature required in the reforming unit is reached, and the at least one gas conveyor is arranged in a cool cycle section of the Anodengaskreislaufs, in which cool cycle section in fuel cell operation, an anode gas temperature below the prevailing in the hot cycle section temperature is achieved
    With the method according to the invention, the target conflicts usually occurring in an anode recirculator can be ensured, namely to prevent or reduce thermoelectric voltages in the fuel cells and at the same time keep the anode gas inlet temperature in a gas conveying device, for example an anode gas blower, as low as possible To save material of the gas conveyor and to achieve a higher flow rate or greater delivery efficiency, be solved together. Furthermore, it is ensured for the use of the reformer, that the operating temperatures required for the reforming of at least 50Q ° C are achieved without external heating, since the reformer is placed in a hot cycle section in which the required for the reforming equilibrium temperature of about 470 ° C is exceeded , Thus, advantageously, the desired anode gas composition for the anode reaction in the anode compartment of the high-temperature fuel cell is achieved without having to externally heat the reformer.
    Advantageous further refinements and developments of the invention are set forth in the subclaims and the description.
    Particularly advantageously, in a process according to the invention in the at least one reforming unit by an endothermic steam reforming of a carbonaceous mixture containing the fuel and the recirculated anode exhaust gas, a reformate gas can be prepared as a mixture of carbon monoxide and hydrogen.
    Steam reforming is a process for the production of synthesis gas or reformate gas, a mixture of carbon monoxide and hydrogen from carbonaceous energy sources such as natural gas, light gasoline,
    Methanol, biogas or biomass. Steam reforming is an all-thermal process in which methane and water vapor are converted to carbon monoxide and hydrogen and proceeds according to the following equation: CH 2+ + H 2 O 5 CO + 3 H 2
    To increase the hydrogen yield, the resulting carbon monoxide can be converted in a further reaction * of the water gas shift reaction to carbon dioxide and further hydrogen: CO + H2O CO2 + K2
    For this purpose, hot steam is mixed with the gas to be reformed (for example natural gas) or with vaporized liquid (for example mineral spirits) and reacted with constant supply of energy to a heterogeneous catalyst in the gas phase.
    In a method according to the invention, it may be particularly expedient for the anode gas temperature in the hot circulation section of the anode gas cycle in which the at least one reforming unit is arranged to be at least 500 ° C., preferably at least 550 ° C., particularly preferably at least 600 ° C. , In this process variant, the anode gas temperature in the hot cycle section is sufficient to heat the reforming unit arranged there and to ensure the required temperature for the reforming of the fuel.
    Also advantageous in a method according to the invention is that the anode gas temperature in the cool Kreisiaufabschnitt of Anodengaskreislaufs, in which the at least one gas conveyor is arranged at most 470 ° C, preferably at most 450 ° C, more preferably at most 400 ° C. In particular, if the gas delivery device is, for example, an anode gas blower, the efficiency of the blower is increased at the comparatively lower temperatures in the cool circulation section of the anode gas circulation. As the temperature decreases, the density of the gas increases and less fan power is needed to deliver the same mass flow. The service life of the gas conveyor is thereby advantageously prolonged.
    In a preferred variant, in a method according to the invention, the at least one reforming unit comprise a reformer which is arranged in the anode gas circulation in the recirculation line downstream of the anode gas heat exchanger and upstream of the gas conveyor, wherein the fuel to be reformed the hot anode exhaust gas in the Anodengasabfeitung before the anode gas heat exchanger and / or the Anodenrecyclegas in the recirculation line is supplied before the reformer or be.
    In this variant, the otherwise necessary long Rezirkulatronsstrecke the Anodengaskreislaufs can be saved by the reformer is arranged directly after the anode gas heat exchanger or immediately downstream of a T-shaped branching of the anode exhaust line on the one hand in the anode gas supply and on the other hand in the Abgasleitüng. The reformer is advantageously no longer additionally heated in this variant. In addition, the gas delivery device, such as the anode fan, is also located downstream of the reformer. The supply of fuel - preferably natural gas is used as fuel - takes place, for example, the hot anode exhaust gas in the anode gas discharge before the anode gas heat exchanger. Advantageously, a good mixing with anode exhaust gas is made possible by this comparatively early addition of the fuel into the anode gas circulation upstream of the reformer via the line to the reformer. However, with this type of admixture, part of the fuel also flows into the exhaust gas line and thus does not reach the reformer.
    Alternatively or in addition to the admixture of the fuel in the anode gas discharge, the fuel may also be supplied to the anode recycle gas in the recirculation line prior to the reformer. Advantageously, the entire admixed fuel thus enters the reformer. However, it should be noted that the reformer inlet temperature of the anode gas due to the admixture of the cooler natural gas so slightly lower. A further advantage of this method variant is that the heat losses associated therewith can be significantly reduced by eliminating the reformer heating. The remaining heat is available for preheating the cathode side. This results in a higher
    Cathode inlet temperature, which is an important factor in thermal management of a fuel cell system.
    The temperature level in the recirculation line of the anode gas is lower with temperatures of, for example, less than 300 ° C., so that the heat losses are less. The lower inlet temperature level at the gas conveyor or at the anode gas blower leads to a higher efficiency of the blower. In addition, less cooling power is required for the anode gas blower and its thermal load is reduced, which allows longer, trouble-free operation of the gas conveyor.
    Due to the higher reformer inlet temperature, no additional external reformer heating or pipelines or controllable throttle valves are necessary. The inlet temperature of the anode gas into the reformer is higher and sufficient to reach the equilibrium temperature. The lack of reforming heating reduces the temperature level in the anode circuit. While this may result in lower anode gas inlet temperatures, which may be critical due to thermal stresses for the high temperature fuel cell, this effect is offset by the reduced heat losses in the recirculation line.
    In a further advantageous variant, in a method according to the invention, the at least one reforming unit may comprise a catalytic reformer heat exchanger in which the fuel is reformed, wherein: the reformer heat exchanger is combined with the anode gas heat exchanger and placed in the anode inlet duct upstream of the anode compartment, the cold heat exchanger side and / or the hot heat exchanger side is coupled to the reformer heat exchanger and the fuel to be reformed is supplied to the hot anode exhaust gas in the anode gas drain on the hot heat exchanger side upstream of the anode gas heat exchanger and / or the anode recycle gas in the recirculation line on the cold heat exchanger side upstream of the anode gas heat exchanger.
    This variant of the method differs from the previously mentioned variants in that the reforming unit and anode gas heat exchangers are combined to form a common component. As a result, a higher reformer inlet temperature is achieved. At the same time both paths of the Anodengaswärmeübertragers, ie the kaite heat exchanger side and the hot heat exchanger side can be performed as a reformer, creating more
    Reformer surface is available and the combination component can be made smaller. However, either only the path of the cold heat exchanger side or only the path of the hot heat exchanger side can each be designed to be reforming or coupled to the reformer heat exchanger.
    The Anodengasejntrittstemperatur in the gas conveyor is lower with the advantages previously described of lower wear and a higher delivery efficiency and a lower required cooling capacity. Furthermore, due to the lower occurring Druekverlusts the required drive power of Gasfördereinriehtung lower. The recirculation line can be made comparatively short and the temperature of the medium flowing therein is low, which advantageously results in only small waste heat losses via the recirculation line.
    In an advantageous development of the invention, the catalytic reformer heat exchanger can be integrated in the anode gas heat exchanger in a variant of the method, wherein the cold heat exchanger side and / or the hot heat exchanger side is or are formed catalytically reforming the fuel.
    In a further alternative embodiment, in a method according to the invention, the at least one reforming unit comprise at least one catalytic reformer anode which is arranged in the anode chamber of the high-temperature fuel cell, wherein the fuel is supplied to the recirculation line of the anode gas cycle and reformed in the anode chamber. Advantageously, a reformer can be omitted in this variant of the method according to the invention. Due to the catalytic activity of a catalytic reformer anode, the reforming of the anode gas can also take place completely in the anode space of the high-temperature natural gas fuel cell.
    In a preferred embodiment of the invention, in one method, the anode of the high temperature fuel cell may be formed as a catalytic reformer anode.
    Due to the catalytic activity of the fuel cell anode, the reforming can also take place completely at the anode of the high-temperature fuel cell. It should be noted that due to the endothermic reforming reaction high thermal stresses can occur at the anode. Furthermore, fuel contaminants such as sulfur can affect the catalytic activity of the reformer anode. Through the use of. Particularly robust reformer anodes, which are largely inert to catalyst poisons of anode gas or of the fuel, sufficient service life for the operation of the high-temperature fuel cell can be ensured in this process variant.
    Suitably, in a method according to the invention, a plurality of reforming units of the same or different design can be arranged in each case in hot circulation sections of the anode gas cycle. For example, in the context of the process according to the invention, a reformer, a catalytic reformer heat exchanger and / or a catalytic reformer anode, which is arranged in the anode compartment of the high-temperature fuel cell, can be used together in the anode circuit and each have a reforming effect.
    The aforementioned object of the present invention to provide corresponding devices for operating a generic fuel cell system with a fuel, which fuel cell system at least one high-temperature fuel cell with at least one arranged in a cathode compartment cathode, with at least one arranged in an anode compartment anode and with an existing between cathode compartment and anode compartment Electrolyte comprises, in an anode gas circulation for the return of anode exhaust gas from the anode space, a fuel supply for mixing fuel to the anode gas flows, wherein at least one gas conveyor for j conveying the Gernischs as anode gas in an anode gas heat exchanger, 1 softer is connected in the anode gas circuit is provided and which
    Fuel cell system further comprises at least one reforming unit for reforming the fuel in the Anodengaskreislauf is from an I
    I r | s
    Device solved in which device, the at least one reforming unit is arranged in a hot cycle section of the Anodengaskreislaufs, in which hot cycle section during operation of the fuel cell system Anodengastemperatur is set above the required in the reforming unit Kalibraturperatur and the at least one gas conveyor arranged in a cool circuit section of the Anodengaskreislaufs is in wetehem cool circuit section during operation of the fuel cell system, an anode gas temperature is set below the prevailing in the hot cycle section anode gas temperature.
    Analogously, the advantages and effects mentioned above for the different methods according to the invention also apply to the corresponding devices for operating a generic fuel cell system with a fuel.
    Advantageously, in a device according to the invention, the at least one reforming unit can be designed for endothermic steam reforming, wherein the anode gas temperature in the hot circulation section of the anode gas circulation, in which the at least one reforming unit is arranged at least 500 ° C, preferably at least 550 ° C, particularly preferred at least 600 ° C, is.
    Suitably, in a device according to the invention at least one reforming unit comprise a reformer which is arranged in the Anodengaskreislauf in the Rezirkulationsleitüng downstream to the anode gas heat exchanger and upstream of the gas conveyor, wherein the fuel supply into the Anodengasableitung before the anode gas heat exchanger and / or in the Rezirkulationsleitüng before the reformer opens ,
    In a further embodiment variant of the invention, in a device the at least one reforming unit may comprise a catalytic reformer heat exchanger, wherein the reformer heat exchanger is combined with or integrated into the anode gas heat exchanger and located in the anode suction line in front of the anode space, the cold heat exchanger side and / or the hot one Heat exchanger side formed kataiytisch reforming or is coupled to the reform heat exchanger or are and the fuel supply into the
    Anodengasableitung opens before the anode gas heat exchanger and / or in the recirculation line before the Refoimerwärmeübertrager.
    In an alternative variant of the invention, in a device the at least one reforming unit may comprise at least one catalytic reformer anode which is arranged in the anode chamber of the high-temperature fuel cell, wherein the anode of the high-temperature fuel cell is preferably designed as a catalytic reformer anode, wherein the fuel feed line opens into the recirculation line of the anode gas cycle.
    According to the invention, different variants of the anode gas circulation or, respectively, different embodiments of the arrangement of reforming unit / gas delivery means / anode gas heat transfer containers are thus possible, as is also carried out in the following figure description.
    In principle, at least one reforming unit is provided in all variants of both the method and the apparatus for operating the generic fuel cell system, which, however, can also be combined with other components as a catalytic reformer heat exchanger or as a catalytic reformer anode. A reforming unit is necessary to ensure the desired anode gas composition or to prevent it in the fuel cell to an uncontrolled reforming, which could lead to thermal stresses and thus damage the fuel cell due to their endothermic nature.
    Further details, features and advantages of the invention will become apparent from the following description of the drawings in each case schematically illustrated, non-limiting embodiments. The following explanations regarding the description of the figures relate to processes as well as devices for operating a fuel cell system. 1 shows a fuel cell system according to the known state of the art, in which an gas circulation device is arranged in an anode gas circulation upstream of a reformer; FIG. 2 is a detailed view of FIG. 1 of the anode gas cycle according to the prior art; FIG. FIG. 3 shows the anode gas cycle of a fuel cell system according to a first embodiment. FIG
    Variant of the invention, wherein the reforming unit comprises a reformer which is arranged in the Anodengaskreislauf in the recirculation line downstream of an anode gas heat exchanger and upstream of a Gasfördereinriehtht, wherein the fuel to be reformed is supplied to the hot anode exhaust gas in the anode exhaust gas upstream of the anode gas heat exchanger; 4 shows the anode gas cycle of a fuel cell system according to a second
    Variant of the invention, wherein a reformer is arranged in the Anodengaskreislauf in the recirculation downstream of an anode gas heat exchanger and upstream of a Gasfordereinrichtung, wherein the fuel to be reformed is supplied to the recycled anode exhaust gas in the recirculation line before the reformer; FIG. 5 shows the anode gas cycle of a fuel cell system according to a third embodiment. FIG
    Variant of the invention, wherein the reforming unit comprises a catalytic reformer heat exchanger, in which the fuel is reformed, wherein the reformer heat exchanger is combined with or integrated into the anode gas heat exchanger; FIG. 6 shows the anode gas cycle of a fuel cell system according to a fourth embodiment. FIG
    Variant of the invention, wherein the reforming unit comprises a catalytic reformer anode, which is arranged in the anode chamber of the high-temperature fuel cell; FIG. 7 shows the anode gas circuit of an inventive device shown in FIG. 3
    Fuel line system during startup of the fuel cell system.
    By way of example, FIG. 1 shows a fuel cell system 1 known per se with a so-called solid oxide fuel cell 10 (SOFC), which is a high-temperature fuel cell 10 operating at operating temperatures of about 650.degree. C. to 1000.degree is operated. The electrolyte 15 of this cell type is made of a solid ceramic material capable of conducting oxygen ions but insulating for electrons. On both sides of the electrolyte layer 15, the electrodes, cathode 11 and anode 13 are mounted. They are gas-permeable electrical conductors. The oxygen ion-conducting electrolyte 15 is provided, for example, as a thin membrane in order to be able to transport the oxygen ions with low energy. It works only at the prevailing high temperatures The side facing away from the electrolyte, the outer side of the cathode 11 is surrounded by air, the outer anode side 13 of fuel gas. Unused air and unused fuel gas and combustion products are extracted.
    Solid oxide fuel cells 10 are galvanic cells for continuous electrochemical power generation, which are usually operated as a fuel cell stack, so-called SOFC stacks, that is, as an interconnection of a plurality of high-temperature fuel cells 10. For clarity, only a single high-temperature fuel cell 10 is illustrated in Figure 1. The function of each galvanic cell and any electrochemical reaction is based on a redox reaction in which reduction and oxidation occur spatially separated, namely at the interface between the electrode and the electrolyte. In solid oxide fuel cell 10, this redox reaction is a reaction of oxygen with the fuel, which may be hydrogen, but here also includes, for example, carbon monoxide. Excess oxygen prevails on the cathode side 12, whereas oxygen deficiency prevails on the anode side 14 because the oxygen present reacts with the hydrogen present, for example. Owing to this concentration gradient, oxygen 19 diffuses from the cathode T1 through the electrolyte 15 to the anode 13. The electrolyte 15 in between, however, is only permeable to oxygen ions.
    When the oxygen molecule reaches the interface between the cathode and the electrolyte, it absorbs two electrons, becoming an ion and penetrating the barrier. Arrived at the border to the anode 13, it reacts catalytically with the fuel gas with release of heat and the corresponding combustion products, and again emits two electrons to the anode. The prerequisite for this is a current flow - the actual purpose of the high-temperature combustion chamber - whereby the current flow can be used for other purposes.
    According to the variant shown in FIG. 1, an anode gas circuit 20 is provided, which is shown in detail in FIG. In the anode gas circuit 20, hot anode exhaust gas 22 is conveyed from the anode compartment 14 of the high-temperature fuel cell 10 to an anode gas heat exchanger 70 in the anode gas heat exchanger 70, which is preferably operated in countercurrent, and the anode exhaust gas line 21 is cooled in the anode exhaust gas line 70
    Anodengaswärmeübertrager 70 as hot anode exhaust gas 23 leaves again A portion of the hot anode exhaust gas 23 passes here in a T-shaped circuit branching in a recirculation line 24 and is recycled as Anodenrecyqlegas 25 or as recirculated anode exhaust gas 25 in the Anodengaskreislauf 20 and fresh fuel 27, the off a fuel supply line 26, which opens into the Anodengaskreislauf 20, mixed.
    The mixture of recirculated anode exhaust gas 25 and fresh fuel 27, the anode gas 29, is now supplied in an anode gas supply line 28 with a gas conveyor 50, which is designed here as Anodengasgebläse 50, a downstream of the anode gas blower 50 subsequent reforming unit 60 with a reformer 61. Furthermore, in the anode gas supply line 28, a steam line, which is fed by an evaporator 90: opens and can be injected with the water vapor 91. The anode gas 29 leaves after the reforming step in the reformer 61 as reformed anode gas 30 and passes in an anode gas line 31 in the anode gas heat exchanger 70 is heated in this and fed to the anode chamber 14 as a hot Anodenzugas 32. A portion of the hot anode exhaust gas 23 is not recycled, but discharged in an exhaust pipe 33 from the anode gas circuit 20 and leaves it as exhaust 34th
    In the recirculation line 24 here is a pressure gauge 40, for example, a Venturi tube 40, installed to measure the flow rate in the Anodengaskreislauf 20 by differential pressure measurement. This Druekmessgerät 40 is optional and can also be omitted. As fuel 27 here natural gas (English: Natural Gas, NG) is fed into the Anodengaskreislauf 20. With the anode gas blower 50 arranged upstream of the reformer 61, the anode gas recirculation is maintained. The anode gas heat exchanger 70 is disposed between reformer 61 and anode chamber 14. As can be seen in FIG. 2, the path of the anode gas 30,32 to be heated, which is supplied to the anode chamber 14, forms a cold heat exchanger side 71, which comes from the hot anode exhaust gas 22, 23 that comes from the anode chamber 14 in the anode exhaust gas line 21 flows and forms a hot heat transfer side 72 of the Anodengaswärmeübertragers 70, is heated.
    In the variant shown in FIG. 1, the reformer 61 is heated by hot burner exhaust gas 86, which originates as exhaust gas from a catalytic afterburner 80 or from a burner 85. Furthermore, in Fig. 1, a supply air line 35 for supplying supply air 36 by means of an air blower 37 including air preheater 38 and corresponding valves 45, for example, throttle valves 45, referred to in the lines. The gas delivery device 5: 0 or the anode gas blower 50 is provided with a cooling device 51 which serves to cool the bearing and the motor of the gas delivery device 50. Due to the cooling 51 necessary for the operation of the anode gas blower 50, however, a significant cooling of the anode recirculation gas between the inlet and outlet of the anode gas blower 50 results. This cooling in the anode gas supply line 28 to a temperature of approximately 400 ° G, however, causes an underflow line in the upstream the anode gas blower 50 subsequent reformer 61 at least required equilibrium temperature of about 470 ° C to start the Refömierungsreaktion.
    For this reason, or in order to substitute the required on the input side of the reformer 61 temperature of Reformierungsreaktiön of at least 500 ° C, the reformer 61 must be additionally heated with burner exhaust gas 86, which then leaves the system 1 as a cooled burner exhaust 87. A further disadvantage of the process variant shown in FIGS. 1 and 2 results - in addition to the required anode gas cooling for the operation of the anode gas blower 50 and the subsequent additional heating of the reformer 61 - through additional heat losses 100 in the comparatively long recirculation line 24 between anode gas heat exchanger 70 and anode gas blower 50 ,
    FIG. 3 illustrates the anode gas cycle 20 of a fuel cell system 1 according to a first variant of the invention, wherein the reforming unit 60 has a
    Reformer 61, which is arranged in the AnodengaskreisJauf 20 in the recirculation line 24 downstream of an anode gas heat exchanger 70 and upstream of a gas conveyor 50. The fuel 26 to be reformed is supplied to the hot anode exhaust gas 22 in the anode exhaust gas line 21 before the anode gas heat exchanger 70. The fuel supply is symbolized by an arrow 27. The anode gas temperature 200 in a hot cycle section 210 of the anode gas cycle 20, in which the Reförmierungseinheit 60 is arranged here is for example 560 ° G,
    The anode gas temperature 200 in a cool cycle section 220 of the anode gas cycle 20 downstream of the hot runner section 210 in the downstream direction and in which the gas conveyor 50 is located is at most 470 ° C. The anode gas temperature 200 after the anode gas blower 50 here is 270 ° C. and is further cooled in the anode gas supply line 31, which is why the anode gas 30 before the anode gas heat exchanger 70 on the cold heat exchanger side 71 has an anode gas temperature 200 of about 250 ° C. The anode gas 32 is heated when passing through the comparatively cold heat exchanger side 71 and, after the anode gas heat exchanger 70, has an anode gas temperature 200 of 700 ° C., with which the heated anode gas 32 reaches the anode compartment 14. When the anode gas exits the anode chamber of the high-temperature fuel cell 10, the
    Anode gas temperature 200 in the anode exhaust line 21 here about 820 ° G. The anode gas 29, which reaches the anode gas heat exchanger 70 here with an anode gas temperature 200 of approximately 800 ° C., thus forms its hot heat exchanger side 72,
    After passing through the comparatively hot heat exchanger side 72 of the Anodengaswärmeübertragers 70, the anode gas temperature 200 of the anode gas 29 before the reformer 60 here about 560 ° C, as illustrated here in Fig. 3 in this device according to the invention a
    Fuel cell system 1 no additional heating of the reforming unit 60 required.
    4 shows the anode gas circuit 20 of a fuel cell system 1 according to a second variant of the invention, wherein the reforming unit 60 comprises a reformer 61 which is arranged here in the anode gas circuit 20 in the recirculation line 24 downstream of an anode gas heat exchanger 70 and upstream of a gas conveyor 50. The reformer 61 is thus arranged in the anode gas cycle 20 between the upstream anode gas heat exchanger 70 and the downstream gas conveyor 50. In contrast to the variant shown in FIG. 3, in FIG. 4 the fuel 26 to be reformed is fed to the recirculated anode exhaust gas 29 in the recirculation line 24 directly upstream of the reformer 61. The fuel supply is symbolized by an arrow 27.
    5 illustrates the anode gas cycle 20 of a fuel cell system 1 according to a third variant of the invention, wherein the reforming unit 60 here comprises a catalytic reformer heat exchanger 62 in which the fuel is reformed, with the reformer heat exchanger 62 being combined with or integrated into the anode gas heat exchanger 70. 5, it is also possible, with the variant shown in FIG. 5, to optionally provide the fuel supply 27 with fuel 26 to be reformed in the anode exhaust gas line 21 upstream of the anode gas heat exchanger 70, the fuel 26 in this case hot anode exhaust gas 22 is supplied. Or the fuel supply 27 is arranged so that the fuel 26 is mixed into the anode exhaust gas line 31 just before the gas delivery device 50. This alternative variant of the fuel supply 27 is shown by dashed lines in Fig. 5. Likewise, it is possible within the scope of the invention to realize the fuel supply 27 at several points of the fuel cell system 1.
    Particularly advantageous here is the variant shown in FIG. 5 * that in the catalytic reformer heat exchanger 62, the reforming unit 60 and the anode gas heat exchanger 70 are combined to form a common component. The reformer heat exchanger 62 is arranged in the hot circulation section 210 of the Anpdengaskreislaufs. The anode gas temperature 200 in the hot cycle section 210 of the anode gas cycle 20, in which the reformer heat exchanger 62 is arranged. here is for example 800 ° C. The anode gas temperature 200 in a cool cycle section 220 of the anode gas cycle 20, which is the hot cycle section 210 in the downstream
    Direction downstream and in which the gas conveyor 50 is arranged here is at most 450 ° C,
    The anode gas temperature 200 after the anode gas blower 50 here is 270 * 0 and is further cooled in the anode gas supply line 31, which is why the anode gas 30 before the anode gas heat exchanger 70 on the cold heat exchanger side 71 has an anode gas temperature 200 of about 250 ° C. The anode gas 32 is heated when passing through the comparatively cold heat exchanger side 71 and, after the anode gas heat exchanger 70, has an anode gas temperature 200 of 700 ° C., with which the heated anode gas 32 reaches the anode compartment 14. When the anode gas exits the anode chamber of the high-temperature fuel cell 10, the anode gas temperature 200 in the anode exhaust gas line 21 here is about 820 ° C. The anode gas 29, which reaches the anode gas heat exchanger 70 here with an anode gas temperature 200 of approximately 800 ° C., thus forms its hot heat exchanger side 72.
    After passing through the comparatively hot heat exchanger side 72 of the reformer heat exchanger 62, the anode gas temperature 200 of the anode gas 29 after the reformer 60 here is about 470 ° C. As illustrated in FIG. 5, in this device according to the invention of a fuel cell system 1, likewise no additional heating of the reforming unit 60 is required.
    6 shows the anode gas cycle 20 of a fuel cell system 1 according to a fourth variant of the invention, wherein the reforming unit 60 comprises a catalytic reformer anode 63 which is arranged in the anode chamber 14 of the high-temperature fuel cell 10. The fuel 27 is supplied to the anode gas circulation 20 or the recirculation line 24 before the anode gas blower 50. The anode gas blower 50 is located in a cool KreislaufabsGhnitt 220 of the Anodengaskreislaufs 2Q.
    The temperature 200 of the anode gas 29 before the anode gas blower 50 is about 340 ° C and decreases after the anode gas blower 50 to a temperature 200 of about 300 ° G from. The anode gas 30 thus occurs at the cold heat exchanger side 71 in the anode gas heat exchanger 70 with about 300 ° G a. The anode gas 32 is heated when passing through the comparatively cold heat exchanger side 71 and, after the anode gas heat exchanger 70, has an anode gas temperature 200, for example of about 780 ° C., with which the heated anode gas 32 reaches the anode chamber 14. The reforming takes place at the catalytic reformer anode 63. At the outlet of the reformed anode gas from the anode chamber 14 of the HochtemperaturbrennstoffzeIle 10, the anode gas temperature 200 in the anode exhaust line 21 here, for example, about 820 ° C.
    The anode chamber 14 together with the catalytic reformer anode 63 disposed therein is located in the hot circulation section 210 of the anode gas circuit 20. The hot anode exhaust gas 22, which here passes with an anode gas temperature 200 of about 800 ° C in the anode gas heat exchanger 70, thus forming the hot heat exchanger side 72nd Nach Passing the comparatively hot heat exchanger side 72 of the Anodengaswärmeübertragers 70, the anode gas temperature 200 of the anode exhaust 23 and the Anoderecyclegases 25 here about 36GeG. As illustrated in FIG. 6, in this device according to the invention of a fuel cell system 1, likewise no additional heating of the reforming unit 60 is required.
    FIG. 7 shows the anode gas circuit 20 of a fuel cell system 1 according to the invention shown in FIG. 3 during startup of the fuel cell system 1. In certain operating phases of the fuel cell system 1 according to the invention, it may be necessary to supply water vapor externally into the system 1, since, for example, at startup by the anode gas recirculation -up, standby or part load operation no or not enough water vapor is returned.
    To prevent this, so far had to steam in one
    Produced evaporator heat exchanger and optionally fed to the system, which, however, additional investment and operating costs and undesirable pressure losses due to the required number of
    Conditioners arise.
    In Fig. 7, therefore, an alternative embodiment is shown, in which case a water injection 110 is provided, with the water 111, preferably below
    Pressure is injected through an injection nozzle in the anode gas stream and thereby directly evaporated. The water 111 is here injected at a temperature 200 of about 95 ° G ih the Anodenzugasleitung 32 after the anode gas heat exchanger 70, the anode gas 32 has about an anode gas temperature 200 of 140 ° C and is cooled by the injected water 111 to about 100 ° C. before the anode gas 32 enters the anode compartment 14. In contrast to the previously known state of the art in which water vapor is supplied to the system, the spraying or injection of water is technically much easier and less expensive to accomplish.
    权利要求:
    Claims (15)
    [1]
    claims
    1. A method for operating a fuel cell system (1) with a fuel (27), which fuel cell system (1) at least one Hoohtemperaturbrennstoffzelle (10) with at least one in a cathode compartment (12) arranged cathode (11), with at least one in a paving space ( 14) arranged anode (13) and with a between cathode space (12) and anode space (14) existing electrolyte (15), wherein in an anode gas circulation (20) from the anode space (14) of at least one Hochtemperaturbrennstoffzelie (10) recycled anode exhaust gas ( 25) is mixed with fuel (27) and supplied as an anode gas (30) with at least one gas delivery device (50) to an anode gas heat exchanger (70) in which the anode gas (31) is thermostated, wherein further in at least one reforming unit (60, 61) in the anode gas circulation (20) of the fuel (27) is reformed, characterized in that the at least one reforming unit (60, 61. ·, 62, 63) in ei nem hot circuit section (210) of the Anodengaskreislaufs (20) is arranged in which hot cycle section (210) in fuel cell operation, an anode gas temperature (200) above the in the reforming unit (60, 61, 62, 63) required equilibrium temperature is reached, and at least a gas delivery device (50) is arranged in a cool circulation section (220) of the anode gas circulation (20), in which cool circulation section (220) in fuel cell operation an anode gas temperature (200) is reached below the anode gas temperature (200) prevailing in the hot circulation section (210).
    [2]
    2. The method according to claim 1, characterized in that in the at least one reforming unit (60, 61, 62, 63) by an endothermic steam reforming of a carbonaceous mixture containing the fuel (27) and the recirculated anode exhaust gas (25) a reformate gas as a mixture produced by carbon monoxide and hydrogen.
    [3]
    3. The method according to claim 1 or 2, characterized in that the anode gas temperature (200) in the hot cycle section (210) of the Anodengaskreislaufs (20), in which the at least one reforming unit (60, 61, 62, 63) is arranged, at least 5Q0 ° C, preferably at least 550 ° C, more preferably at least 600 ° C, is
    [4]
    4. The method according to any one of claims 1 to 3, characterized in that the anode gas temperature (200) in the cool circulation section (220) of the Anodengaskreislaufs (20), in which the at least one Gasförderejnrichtung (50) is arranged, at most 470 ° C, preferably at most 450 ° C, more preferably at most 400 ° C, is.
    [5]
    5. The method according to any one of claims 1 to 4, characterized in that the at least one reforming unit (60) comprises a reformer (61) in the Anodengaskreislauf (20) in the recirculation line (24) downstream to the anode gas heat exchanger (70) and upstream in front of the gas delivery device (50), wherein the fuel (27) to be reformed precedes the hot anode exhaust gas (22) in the anode gas discharge (21) before the anode gas heat exchanger (70) and / or the anode recycle gas (26) in the recirculation line (24) the reformer (61) is supplied or be.
    [6]
    6. The method according to any one of claims 1 to 5, characterized in that the at least one reforming unit (60) comprises a catalytic heat exchanger Ver¬ (62), in which the fuel (27) is reformed, wherein the reformer heat exchanger (62) with the anode gas heat exchanger ( 70) is combined and arranged in the Anodenzugasleitung (31) in front of the anode chamber (14), wherein the cold heat exchanger side (71) and / or the hot heat exchanger side (72) is coupled to the heat exchanger (62) and are to be reformed Fuel (27) the hot anode exhaust gas (22) in the anode gas discharge line (21) on the bite heat exchanger side (72) before the anode gas heat exchanger (70) and / or the Anoderecyclegas (25) in the recirculation line (24) on the cold heat exchanger side (71) is supplied before the anode gas heat exchanger (70) or be.
    [7]
    7. The method according to claim 6, characterized in that the catalytic reformer heat exchanger (62) in the anode gas heat exchanger (70) is integrated, wherein the cold heat exchanger side (71) and / or the hot heat exchanger side (72) the fuel (27) is formed catalytically reforming or are.
    [8]
    8. The method according to any one of claims 1 to 7, characterized in that the at least one reforming unit (60) comprises at least one catalytic reformer anode (63) which is arranged in the anode chamber (14) of the Hochtemperaturbrennstöffzelle (10), wherein the fuel (27 ) is supplied to the recirculation line (24) of the anode gas circulation (20) and is reformed in the anode space (14),
    [9]
    9. The method according to claim 8, characterized in that the anode (13) of the high-temperature fuel cell (10) is designed as a catalytic reformer anode (63).
    [10]
    10. The method according to any one of claims 1 to 9, characterized in that a plurality of reforming units (60, 61,62,63) of the same or different type each in hot circulation sections (210) of the anode gas circulation (20) are arranged.
    [11]
    11. An apparatus for operating a fuel cell system (1) with a fuel (27), which fuel cell system (1) at least one high-temperature fuel cell (10) having at least one in a cathode chamber (12) arranged cathode (11), with at least one in an anode compartment ( 14) arranged anode (13) and with a between cathode space (12) and anode space (14) existing electrolyte (15), wherein in an anode gas circuit (20) for returning anode exhaust gas (25) from the anode space (14) a fuel supply line (26) for adding fuel (27) to the anode gas (25), at least one gas conveying device (50) for conveying the mixture as anode gas (30) into an anode gas heat exchanger (70) which is connected in the anode gas circuit (20) is provided, which Brennstöffzellensystem (1) further comprises at least one reforming unit (60, 61) for reforming the fuel (27) in the Anodengaskreislauf, characterized gekennze that the at least one reforming unit (60, 61, 62, 63) is arranged in a hot circulation section (210) of the anode gas cycle (20), in which hot cycle section (210) during operation of the fuel cell system (1) an anode gas temperature (200) is set above the equilibrium temperature required in the reforming unit (60, 61, 62, 63), and the at least one gas delivery device (50) is arranged in a cool circulation section (220) of the anode gas cycle (20), in which cool circulation section (220) is in operation of the fuel cell system (1), an anode gas temperature (200) is set below the anode gas temperature (200) prevailing in the hot circuit section (210).
    [12]
    12. The device according to claim 11, characterized in that the at least one reforming unit (60, 61, 62, 63) is designed for endothermic steam reforming, wherein the anode gas temperature (200) in the hot circuit section (210) of the anode gas cycle (20), in in which the at least one reforming unit (60, 61, 62, 63) is arranged is at least 500 ° C, preferably at least 550 ° C, particularly preferably at least 600 ° C,
    [13]
    13. The apparatus of claim 11 or 12, characterized in that at least one reforming unit (60) comprises a reformer (61) in the Anodengaskreislauf (20) in the recirculation line (24) downstream to the anode gas heat exchanger (70) and upstream of the gas conveyor (50) is arranged, wherein the fuel supply line (26) in the Anodengasableitung (21) before the anode gas heat exchanger (70) and / or in the recirculation line (24) before the reformer (61) opens
    [14]
    14. Device according to one of claims 11 to 13, characterized in that the at least one reforming unit (60) comprises a catalytic reformer heat exchanger (62), wherein the reformer heat exchanger (62) with the Anpdengaswärmeübertrager (70) combined or integrated in this and in the anode exhaust gas line (31) is arranged in front of the anode chamber (14), wherein the cold heat exchanger side (71) and / or the hot heat exchanger side (72) is catalytically reforming or is coupled to the reformer heat exchanger (62) and the fuel supply line (26 ) into the anode gas discharge line (21) before the anode gas heat exchanger (70) and / or into the recirculation line (24) before the reformer heat exchanger (62) opens.
    [15]
    15. Device according to one of claims 11 to 14, characterized in that the at least one reforming unit (60) comprises at least one catalytic reformer anode (63) which is arranged in the anode chamber (14) of the high-temperature fuel cell (10), wherein preferably the anode ( 13) of the high-temperature fuel cell (10) is designed as a catalytic reformer anode (63), wherein the fuel supply line (26) opens into the recirculation line (24) of the anode gas circuit (20).
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    同族专利:
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    DE102016223436A1|2017-06-22|
    AT518012B1|2018-04-15|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    EP1506589A1|2002-05-21|2005-02-16|Ceramic Fuel Cells Limited|Fuel cell system|
    WO2007087305A2|2006-01-23|2007-08-02|Bloom Energy Corporation|Integrated solid oxide fuel cell and fuel processor|
    US20110111314A1|2009-06-16|2011-05-12|Jingyu Cui|Systems and processes for operating fuel cell systems|
    AT521650B1|2018-08-23|2020-09-15|Avl List Gmbh|Fuel cell system and method of operating the same|
    法律状态:
    优先权:
    申请号 | 申请日 | 专利标题
    ATA765/2015A|AT518012B1|2015-11-26|2015-11-26|Apparatus and method for operating a fuel cell system|ATA765/2015A| AT518012B1|2015-11-26|2015-11-26|Apparatus and method for operating a fuel cell system|
    DE102016223436.6A| DE102016223436A1|2015-11-26|2016-11-25|Apparatus and method for operating a fuel cell system|
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