DE102021207632A1 - Fuel cell system and recirculation device for recirculating anode exhaust gas in a fuel cell system - Google Patents

Abstract

A recirculation device for recirculating anode exhaust gas in a fuel cell system comprises a fan with a suction port for connection to a fuel outlet of a fuel cell assembly of the fuel cell system, a pressure port for connection to a fuel inlet of the fuel cell assembly and an impeller for conveying the anode exhaust gas from the inlet to the outlet. Furthermore, the recirculation device has a turbine with an inlet for connection to a fuel tank of the fuel cell system, an outlet for connection to the fuel inlet of the fuel cell arrangement and a turbine wheel which is kinematically coupled to the impeller of the fan and which can be flown through the inlet with gaseous fuel from the fuel tank and can be rotated is to drive the impeller of the fan.

Description

technical field

The present invention relates to a fuel cell system and a recirculation device for recirculating anode exhaust gas in a fuel cell system.

State of the art

Fuel cells are increasingly used as energy converters, including in vehicles, to convert chemical energy stored in a fuel, such as hydrogen, directly into electrical energy together with oxygen. Fuel cells typically have an anode, a cathode, and an electrolytic membrane positioned between the anode and the cathode. The fuel is oxidized at the anode and the oxygen is reduced at the cathode. This creates water on the cathode side.

Typically, the anode of fuel cells is continuously supplied with excess gaseous fuel, that is, more fuel than would be stoichiometrically necessary for a given amount of oxygen supplied to the cathode. The excess fuel or the anode output is usually recirculated or fed back to the anode. This is typically done using a recirculation fan that circulates the anode exhaust from an outlet of the anode back to the inlet of the anode.

The recirculation fan is usually operated by an electric motor. To improve the energy efficiency of a fuel cell system is in the DE 10 2007 037 096 A1 discloses driving the recirculation fan by means of a turbine. The turbine uses compressed air as the working fluid, which has been compressed by means of a compressor for supply to the cathode.

Disclosure of Invention

According to the invention, a recirculation device having the features of claim 1 and a fuel cell system having the features of claim 9 are provided.

According to a first aspect of the invention, a recirculation device for recirculating anode exhaust gas in a fuel cell system comprises a fan with a suction port for connection to a fuel outlet of a fuel cell arrangement of the fuel cell system, a pressure port for connection to a fuel inlet of the fuel cell arrangement and an impeller for conveying the anode exhaust gas from the suction port to the Pressure connection and a turbine with an inlet for connection to a fuel tank of the fuel cell system, an outlet for connection to the fuel inlet of the fuel cell arrangement and a kinematically coupled to the impeller of the fan turbine wheel, which can flow through the inlet with gaseous fuel from the fuel tank and is rotatable, to drive the fan impeller.

According to a second aspect of the invention, a fuel cell system comprises a fuel cell arrangement having at least one fuel cell, a fuel inlet and a fuel outlet, and a recirculation device according to the first aspect of the invention, wherein the pressure port of the fan and the outlet of the turbine are connected to the fuel inlet, and wherein the The suction port of the blower is connected to the fuel outlet.

One idea on which the invention is based is to partially break down the kinetic energy of a fuel flow that is supplied to the fuel cell system, e.g. from a tank, in a turbine and to use the turbine to drive a blower in order to recirculate anode waste gas. For this purpose, according to the invention, an impeller of the turbine, which is driven by the fuel, such as hydrogen, and an impeller of the fan, which conveys the anode exhaust gas, are kinematically coupled to one another, e.g. via a shaft, a flange or by the turbine wheel and the impeller being in one piece are trained. Typically, the fuel is present in the tank at a pressure in a range between 8 bar and 20 bar and is supplied to an anode of the fuel cell assembly at a pressure in a range between 1.5 bar and 3.5 bar. The pressure difference can advantageously be reduced in the turbine and used to drive the fan.

By using the kinetic energy of a fuel flow that is supplied to the fuel cell system in a turbine to drive the fan that recirculates the anode exhaust gas, the energy efficiency of the fuel cell system is advantageously improved.

Advantageous refinements and developments result from the further dependent claims and from the description with reference to the figures of the drawing.

According to some embodiments, it can be provided that the turbine wheel is designed as a Tesla turbine with at least two first disks extending in parallel, which kinematically are coupled to the impeller of the fan, with at least one nozzle connected to the inlet being arranged in the area of an outer circumference of the first discs, which is aligned in such a way that fuel can be blown tangentially to the outer circumference into a space between the discs, and the outlet of the turbine is located in a central portion of the first disks with respect to a radial direction. An advantage of this structure is that the turbine can be operated with very little noise and vibration, which is particularly advantageous for applications in the motor vehicle sector. A further advantage lies in the structurally simple structure, since the discs can each be designed as simple discs with a circular circumference and flat surfaces.

According to some specific embodiments, it can be provided that the first disks of the turbine wheel and the impeller of the fan are coupled via a common shaft. Accordingly, the first disks and the impeller can be spaced apart in the axial direction and sit on one and the same shaft. This further simplifies the structural design of the recirculation device. Optionally, the shaft may have exhaust ports communicating with the space between the first disks to exhaust the fuel gas introduced into the space. The outlet openings thus form the turbine outlet or are connected to it.

According to some embodiments, it can be provided that the blower is designed as a Tesla compressor with at least two second disks extending in parallel, with a central area of the second disks in relation to the radial direction being connected to the suction port, and the pressure port being connected to a Outer circumference of the second discs is connected. For example, the first disks of the turbine and the second disks of the fan can be arranged on the same shaft. The shaft may optionally include inlet ports located between the second disks to deliver anode exhaust into the space between the second disks. A collection chamber can be formed or provided on the outer circumference of the second discs, which is connected to the pressure connection of the fan. In particular, the realization of the turbine and compressor as a Tesla turbine or compressor offers the advantage of a particularly simply constructed unit.

According to some embodiments, it can be provided that the fan and the turbine are arranged in a common housing, and the housing has an outlet connection to which the outlet of the turbine and the pressure connection of the fan are connected. For example, the turbine wheel and the impeller of the fan can be separated from one another by a separating disk rotating with the impeller and the turbine wheel, the separating disk dividing the housing into a fan section and a turbine section, in particular with respect to an axial direction. A stub or the like can be provided on the housing, which stub has the outlet connection, the stub being connected to the outlet of the turbine and the pressure connection of the fan. For example, the partial turbine area can be connected to the socket by a channel or an opening that forms the outlet. Likewise, the partial fan area can be connected to the connecting piece by a duct or an opening that forms the pressure connection. The integration of the blower and the turbine in a common housing with a common connection results in an even more compact construction of the recirculation device.

According to some embodiments, it can be provided that the recirculation device has a drive device that is kinematically coupled to the impeller of the fan, in particular in the form of an electric motor. The flexibility of the regulation of the mass flow of fuel that is conveyed by the blower can thus be further increased.

According to some embodiments, it can be provided that the recirculation device has a collection container for collecting liquid water that is separated from the anode waste gas in the blower.

According to some embodiments, it can be provided that the collection container is connected to the blower by one or more lines, the line(s) and/or the collection container being thermally coupled to the drive device. For example, the drive can protrude into the collection container or the lines can or the lines can run along the drive device. This improves the cooling of the drive device and thus its service life.

According to some specific embodiments, it can be provided that the pressure connection of the fan and the outlet of the turbine are connected directly to the fuel inlet without an interposed ejector pump. The combination of turbine and fan can advantageously provide the required recirculation mass flow and the required fresh gas mass flow both at high and at low loads, which regulates the fuel cell system tems simplified. Furthermore, the flow losses in the system are reduced.

According to some specific embodiments, it can be provided that the fuel cell system has a metering valve connected to the inlet of the turbine, which can be connected to a fuel tank and is set up to vary a fuel mass flow supplied to the turbine from the fuel tank.

According to some embodiments, it can be provided that the fuel cell system has a tank which is connected to the inlet of the turbine.

• 1 eine schematische Darstellung eines hydraulischen Schaltbildes eines Brennstoffzellensystems gemäß einem Ausführungsbeispiel der Erfindung;
• 2 eine schematische Schnittansicht einer Rezirkulationsvorrichtung gemäß einem Ausführungsbeispiel der Erfindung;
• 3 eine vereinfachte Draufsicht auf eine Scheibe eines Turbinenrads einer Turbine der in 2 gezeigten Rezirkulationsvorrichtung.

The invention is explained below with reference to the figures of the drawings. From the figures show:

• 1 a schematic representation of a hydraulic circuit diagram of a fuel cell system according to an embodiment of the invention;
• 2 a schematic sectional view of a recirculation device according to an embodiment of the invention;
• 3 a simplified plan view of a disk of a turbine wheel of a turbine in 2 shown recirculation device.

In the figures, the same reference symbols designate identical or functionally identical components, unless otherwise stated.

1 shows a fuel cell system 200 by way of example and in a schematic manner. As in FIG 1 shown by way of example, the fuel cell system 200 may include a tank 205 , a fuel cell assembly 210 , a recirculation device 100 , and a flow control valve 220 .

The tank 205 is designed to store gaseous fuel such as hydrogen at high pressure, eg at a pressure of more than 10 bar. The tank 205 is in 1 purely by way of example as part of the fuel cell system 200 . However, the invention is not limited to this, but the fuel cell system 200 can also be connectable to the tank 205 or another fuel source.

The fuel cell arrangement 210 can have a multiplicity of fuel cells 213 arranged to form a stack. In principle, however, it is also conceivable that only one fuel cell 213 is provided. As in 1 shown schematically, each fuel cell 213 can have an anode 213A, a cathode 213B and an electrolyte 213C arranged between them, for example in the form of an electrolyte membrane.

The fuel cell arrangement 210 has a fuel inlet 211, via which the anode 213A can be supplied with gaseous fuel, e.g. hydrogen or natural gas, and a fuel outlet 212, via which unused or unreacted fuel can be removed from the anode 213A. Unconsumed fuel discharged at fuel outlet 212 may also be referred to as excess fuel or anode exhaust.

As in 1 Also shown, the fuel cell arrangement 210 has an oxygen inlet 214, via which the cathode 213B can be supplied with gaseous oxygen, either as pure oxygen or as oxygen contained in the ambient air, and a product outlet 215, via which unused or unreacted oxygen and chemical Reaction products, in particular water, can be removed from the cathode 213B.

The fuel cell arrangement 210 is supplied with fuel from the tank 205 via a supply line 201 which is connected to the fuel inlet 211 . The anode waste gas or excess fuel exiting at the fuel outlet 212 of the fuel cell arrangement 210 is fed to the recirculation device 100 via a discharge line 202, recirculated by means of the recirculation device 100 and fed back to the fuel inlet together with fresh fuel.

As in 1 shown schematically, the recirculation device 100 comprises a blower 1 and a turbine 2. Optionally, a drive device 4 and/or a collection container 5 can also be provided, as in FIG 1 shown as an example.

Fan 1 is in 1 shown only symbolically and has a suction port 11 connected to the discharge line 202 and a pressure port 12 connected to the supply line 201 . The fan 1 is designed to convey anode waste gas from the fuel outlet 212 to the fuel inlet 211 .

Turbine 2 is in 1 also shown only symbolically and has an inlet 21 which is connected to the tank 205 and an outlet 22 which is connected to the supply line 201 . The turbine 2 is, as in 1 shown schematically, kinematically coupled to the fan 1. The turbine 2 can be flowed through with the fuel present at high pressure from the tank 205 and is designed to be in the flowing fuel to convert stored kinetic energy and thereby drive the fan 1. Thus, the energy efficiency of the fuel cell system 200 can be improved in a simple manner since the energy requirement for driving the blower 1 is reduced. As in 1 is also shown schematically, the pressure connection 12 of the blower 1 and the outlet 12 of the turbine 2 can be connected directly, in particular without an interposed ejector pump, to the fuel inlet 211 of the fuel cell arrangement. As a result, the fuel cell system 200 can be made more compact. However, it is not excluded that further flow components such as valves, humidifiers or dehumidifiers or the like are arranged between the pressure connection 12 of the fan 1 and the fuel inlet 211 or the outlet 12 of the turbine 2 and the fuel inlet 211 .

The optional motor 4 can be an electric motor, for example, and is also kinematically coupled to the fan 1 in order to drive it at least in support of the turbine 2 .

The flow control valve 220 can be arranged, for example, between the tank 205 and the inlet 21 of the turbine 2, as is shown in FIG 1 is shown schematically. The flow control valve 220 can in particular be designed to vary a mass flow of fuel that is supplied to the turbine 2 .

2 shows a schematic sectional view of a recirculation device 100, as is the case, for example, in the case of FIG 1 fuel cell system 200 shown can be installed. As already explained and as in 2 shown, the recirculation device 100 has a fan 1 with a pressure port 11 and a suction port 12 and a turbine 2 with an inlet 21 and an outlet 22 . The blower 1 also has an impeller 10 that can be rotated about an axis of rotation A1 for conveying the anode waste gas from the suction connection 11 to the pressure connection 12 . The turbine 2 has a turbine wheel 20, which can be flown with gaseous fuel from the fuel tank 205 and can be rotated, for example about the same axis of rotation A1 as the impeller 10 of the fan 1. As in FIG 2 is also shown schematically, the recirculation device 100 can also have a housing 3, with the blower 1 and the turbine 2 preferably being housed together in the housing 3.

As in 2 shown as an example, the turbine wheel 20 can be designed as a Tesla turbine. In this case, the turbine wheel 20 has at least two first disks 23 extending in parallel. In 2 a turbine wheel 20 with two discs 23 is shown purely by way of example. The invention is of course not limited to this and a larger number of first disks 23 can also be provided. As in 2 shown, the first disks 23 extend parallel to one another or the first disks 23 have flow surfaces 23b which are oriented towards one another and run parallel. The flow surfaces 23b can be flat, for example, as in 2 shown. The disks 23 are spaced apart along the axis of rotation A1, so that a first intermediate space 25 is formed between two mutually facing flow surfaces 23b. As in 3 As shown, the first disks 23 may have a circular outer periphery 23a.

As in 2 shown schematically, the first disks 23 can be arranged or attached to a shaft 6 in a rotationally fixed manner. The shaft 6 is rotatably mounted about the axis of rotation A1. As in 2 shown, the shaft 6 can be designed as a hollow shaft with an interior. With respect to the axial direction, the interior of the shaft 6 can be divided in particular into a first region 60A and a second region 60B which is fluidically separate therefrom, for example by a partition. The shaft 6 can have a plurality of first outlet openings 61, which are arranged between the disks 23 with respect to an axial direction running parallel to the axis of rotation A1, so that the intermediate space 25 between the disks 23 communicates with the interior of the shaft 6, in particular with the first region 60A of the interior are connected.

As in 2 and in the top view of the 3 As can be seen, at least one nozzle 24 can be arranged in the area of the outer circumference 23a of the first disks 32 . In 3 a nozzle 24 is shown as an example. However, a plurality of nozzles 24 can also be distributed along the outer circumference 23a. The nozzle 24 can, for example, protrude through a recess 31 of the housing 3 into an interior space of the housing 3 in which the turbine wheel 20 is arranged, as in FIG 2 shown schematically. The nozzle 24 can form the inlet 21 of the turbine 2 or can be connected to the inlet 21 in general. In 2 is shown by way of example that the nozzle 24 is connected directly to the flow control valve 220 which, as in FIG 2 shown by way of example, can be arranged on the housing 3. The nozzle 24 is aligned in such a way that fuel can be blown into the space 25 between the discs 23 tangentially to the outer circumference 23a in the area of the outer circumference 23a. Thereby, the fuel transmits its momentum to the first discs 23 via viscous interaction with the flow surfaces 23a and is spirally transported inward in the radial direction R1, as shown in FIG 3 by the arrows P20 is indicated symbolically. On the shaft 6, the fuel can be introduced into the shaft 6 through the openings 61, from where it can be discharged via the interior through one or more connection openings 63 formed in a first axial end region of the shaft 6, which form the outlet 22 of the turbine 2 is. The outlet 22 of the turbine 2 is thus arranged in the central area of the first discs 23 with respect to the radial direction R1.

The first disks 3 are kinematically coupled to the impeller 10 of the fan 1 in order to drive it. For example, the impeller 10 and the turbine wheel 20 can be arranged on the same shaft, in particular the shaft 6, as a 2 shown as an example.

The blower 1 can be implemented as a Tesla compressor, for example, as in 2 shown by way of example and schematically, but is not limited to this. As in 2 shown, the blower 1 can have at least two second disks 13 extending in parallel. In 2 an impeller with three discs 13 is shown purely by way of example. Of course, the invention is not limited to this, and a larger or smaller number of second disks 13 can also be provided. As in 2 shown, the second disks 13 extend parallel to one another or the second disks 13 have flow surfaces 13b which are oriented towards one another and run parallel. The flow surfaces 13b can be flat, for example, as in 2 shown. The discs 13 are spaced apart along the axis of rotation A1, so that a second intermediate space 15 is formed between two mutually facing flow surfaces 13b. The second discs 13 can have a circular outer circumference 13a, for example.

The second disks 13 can, for example, be fixed or fastened to the shaft 6 in a rotationally fixed manner. With respect to the axial direction between the first disks 23 and the second disks 13, a cutting disk 18 can be arranged, which is preferably also connected to the shaft 6 in a rotationally fixed manner. The interior of the shaft 6 is also divided in the axial direction. As in 2 shown, the shaft 6 can have a plurality of second outlet openings 62, which are arranged between the disks 13 with respect to an axial direction running parallel to the axis of rotation A1, so that the intermediate space 15 between the second disks 13 communicates with the interior of the shaft 6, in particular with the second area 60B of the interior are connected. As in 2 also shown, the shaft 6 can have an inlet opening 61 in a second axial end region, which in the example of FIG 2 forms the suction port 11 of the blower 1 . When the second disks 13 are rotated about the axis of rotation A1, the fluid or anode waste gas located in the space between the second disks 13 is accelerated by the flow surfaces 13b due to viscous effects and transported radially outwards. Anode waste gas is subsequently supplied from the interior of the shaft 6 through the inlet opening 61 and the openings 62 . Thus, a central portion of the second disks 13 with respect to the radial direction R<b>1 is connected to the suction port 11 .

The pressure connection 12 can be formed, for example, through an opening in the housing 3, in particular in the area of the outer circumference 13a of the second disks 13. In general, the pressure connection 12 can thus be fluidly conductively connected to the outer circumference of the second disks 13.

As in 2 is further shown, the housing 3 may have a first portion 30A, in which the impeller 20 of the turbine 2 is arranged, and a second portion 30B, in which the impeller 10 of the fan 1 is arranged. The first and second sections 30A, 30B can be separated from one another, for example by the separating disk 18, as in FIG 2 shown schematically. Furthermore, the housing 3 can have a third partial area 30C which is separate from the first and second partial area 30A, 30B and into which the second axial end of the shaft 6 protrudes. As in 6 shown schematically, the third partial area 30C can have a connection port 34 for connection to the discharge line 202 or the fuel outlet 212 of the fuel cell system 200 .

The pressure connection 12 of the fan 1 and the outlet 22 of the turbine 2 can each be connected via a duct 35, 36 to a socket 37, which has an outlet connection 32 for connection to the supply line 201 or the fuel inlet 211, as is shown in 2 is shown schematically. Thus, the housing 3 can generally have an outlet port 32 to which the outlet 22 of the turbine 2 and the pressure port 12 of the fan 1 are connected.

As already explained, the drive device 4 can be formed in particular by an electric motor. If fan 1 is constructed as a Tesla compressor, as in 2 shown by way of example, a stator 41 of the electric motor, which has an electrical conductor winding, can be accommodated in a motor housing 40 arranged outside of the housing 3, and a rotor 42, for example in the form of permanent magnets, can be arranged on one of the first second disks 13. However, the invention is not limited to this. For example, the rotor 42 can also be attached to the shaft 6 .

the inside 1 Collecting container 5, shown only schematically, is used to collect water that is separated from the anode waste gas when the impeller 10 of the blower 1 rotates. When the impeller 10 rotates about the axis of rotation A1, the anode off-gas located in the gaps 15 is accelerated in the radial direction R1. Liquid water, which may be contained in the anode waste gas, is conveyed into the radially outer region of the housing 3 due to its high density compared to the gaseous fuel as a result of the centrifugal force and collects there. The water can flow out of the radially outer area of the housing 3, as in 2 shown schematically, are conducted via one or more lines 51 in the collection container 5. As in 2 shown purely as an example, the collection container 5 can completely enclose the motor housing 40 of the electric motor. The outer circumference of the motor housing 40 of the electric motor is thus surrounded by water and thereby cooled. In general, the optional drive device 4 can be thermally coupled to the collection container 5, for example in the manner described above. Alternatively or additionally, the lines 51 can also be thermally coupled to the drive device 4 .

In 2 is shown by way of example that the axis of rotation A1 can be aligned parallel to the direction of gravity g. Since the lines 51 are connected in a radially outer area of the housing 3 or the housing 3 can be provided with corresponding outlet openings (not shown) in the radially outer area, the recirculation device 100 can also be positioned without any problems so that the axis of rotation A1 is inclined is aligned with the direction of gravity g. For example, an inclination up to a predetermined angle α may be possible, with the angle α being in a range between 15 degrees and 45 degrees, for example.

As in 2 is also shown schematically, the collection container 5 can be provided with a drain valve 8, for example in the form of a solenoid valve, to drain the water from the collection container 5 continuously or cyclically.

Furthermore shows 2 schematically that an optional heater 7 can be provided, which is thermally coupled to the collection container 5 and/or the lines 51. The heater 7 serves to prevent the water from freezing at low ambient temperatures and/or to thaw frozen water again.

Although the present invention has been explained above by way of example using exemplary embodiments, it is not limited thereto but can be modified in many different ways. In particular, combinations of the above exemplary embodiments are also conceivable.

QUOTES INCLUDED IN DESCRIPTION

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

Patent Literature Cited

• DE 102007037096 A1 [0004]

Claims (9)

Recirculation device (100) for recirculating anode exhaust gas in a fuel cell system (200), comprising: a blower (1) with a suction port (11) for connection to a fuel outlet (212) of a fuel cell assembly (210) of the fuel cell system (200), a pressure port (12) for connection to a fuel inlet (211) of the fuel cell assembly (210) and a Impeller (10) for conveying the anode exhaust gas from the suction port (11) to the pressure port (12); and a turbine (2) having an inlet (21) for connection to a fuel tank (205) of the fuel cell system (200), an outlet (22) for connection to the fuel inlet (211) of the fuel cell assembly (210) and a kinematically connected to the impeller ( 10) of the fan (1) coupled turbine wheel (20), which through the inlet (21) with gaseous fuel from the fuel tank (205) can flow and rotate to drive the impeller (10) of the fan (1). Recirculation device (100) after claim 1 , wherein the turbine wheel (20) is designed as a Tesla turbine with at least two first disks (23) extending in parallel, which are kinematically coupled to the impeller (10) of the fan (1), wherein in the area of an outer circumference (23a) of the first disks (32) at least one nozzle (24) connected to the inlet (21) is arranged, which is aligned in such a way that fuel can be blown into an intermediate space (25) between the disks (23) tangentially to the outer circumference (23a), and wherein the outlet (22) of the turbine (2) is located in a central portion of the first discs (23) with respect to a radial direction (R1). Recirculation device (100) after claim 2 , wherein the first disks (23) of the turbine wheel (20) and the impeller (10) of the fan (1) are coupled via a common shaft (6). Recirculation device (100) after claim 2 or 3 , wherein the blower (1) is designed as a Tesla compressor with at least two second disks (13) extending in parallel, wherein a central area of the second disks (13) with respect to the radial direction (R1) is connected to the suction connection (11) is connected, and wherein the pressure port (12) is connected to an outer periphery of the second disks (13). Recirculation device (100) according to one of claims 2 until 4 , wherein the fan (1) and the turbine (2) are arranged in a common housing (3), and wherein the housing (3) has an outlet connection (32) with which the outlet (22) of the turbine (2) and the pressure connection (12) of the blower (1) are connected. Recirculation device (100) according to any one of the preceding claims, additionally comprising: a drive device (4) kinematically coupled to the impeller (10) of the fan (1), in particular in the form of an electric motor. Recirculation device (100) after claim 6 , additionally comprising: a collection container (5) for collecting liquid water which is separated from the anode exhaust gas in the blower (1), the collection container (5) being connected to the blower (1) by one or more lines (51). , and wherein the line(s) and/or the collection container (5) is thermally coupled to the drive device (4). Fuel cell system (200), with: a fuel cell arrangement (210) with at least one fuel cell (213), a fuel inlet (211) and a fuel outlet (212); and a recirculation device (100) according to any one of the preceding claims; the pressure port (12) of the fan (1) and the outlet (12) of the turbine (2) being connected to the fuel inlet (211); and wherein the suction port (11) of the fan is connected to the fuel outlet (212). Fuel cell system (200) after claim 8 , wherein the pressure connection (12) of the fan (1) and the outlet (12) of the turbine (2) are connected directly to the fuel inlet (211) without an interposed ejector pump.

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