AT523780A1 - Separation device for separating liquid water from a recirculation gas in a fuel cell system - Google Patents

Abstract

The present invention relates to a separating device (10) for separating liquid water (W) from a recirculation gas (RG) in a recirculation section (160) of a fuel cell system (100), having a base body (20) with a cyclone section (30) with a spiral cross-section for separating liquid water (W) from the recirculation gas (RG) and a collecting section (40) for collecting the separated liquid water (W), the base body (20) having at least one gas inlet (22) upstream of the cyclone section (30) for the inlet of recirculation gas (RG) and a gas outlet (24) downstream of the cyclone section (30) for the outlet of recirculation gas (RG).

Description

Separation device for separating liquid water from one

Recirculation gas in a fuel cell system

The present invention relates to a separating device for separating

liquid water from a recirculation gas in a recirculation section of a fuel cell system, a fuel cell system with at least one such separating device and a method for assembling such a device

Separating device.

It is basically known that exhaust gases can contain water in fuel cell systems. This is in particular condensation water that has been formed in the corresponding exhaust gas, for example the anode exhaust gas or the cathode exhaust gas. It is also known to separate such water, also referred to as product water, in the respective exhaust gas and to discharge it from the fuel cell system or within the

To continue to use the fuel cell system.

In order to perform such a water separation in known fuel cell systems, a corresponding water separator is usually arranged in the anode discharge section and / or in the cathode discharge section, which such liquid water, which usually comprises product water and condensed water, to the environment via a so-called drain valve

can discharge or feed it back into the system.

However, the known solutions have the disadvantage that current water separators are and / or comprise simple components and do not have the high degree of integrated functions. This means that space-intensive solutions are necessary in order to integrate all the desired functions into the system. In addition, current solutions are only designed for a single installation direction and do not offer the option of being installed in a different position. Furthermore, the flow guidance of the current separator is not designed for the requirements of passive recirculation. Current separators can only be used for a single fuel cell stack and not for fuel cell systems with multiple stacks

be used.

It is the object of the present invention to provide those described above

To remedy disadvantages at least partially. In particular, it is the task of

present invention, in a cost-effective and simple manner, the separation of

To simplify product water and in particular in the system of the

To integrate the fuel cell system as well as possible.

The above object is achieved by a separating device with the features of claim 1, a fuel cell system with the features of claim 12 and a method with the features of claim 15. Further features and details of the invention emerge from the dependent claims, the description and the drawings . Features and details that are described in connection with the separating device according to the invention naturally also apply in connection with the fuel cell system according to the invention and the method according to the invention and in each case vice versa, so that with regard to the disclosure of the individual aspects of the invention

is or can always be referred to reciprocally.

According to the invention, a separating device for separating liquid water from a recirculation gas in a recirculation section of a fuel cell system is proposed. For this purpose, such a separating device has a base body with a cyclone section with a spiral cross-section for separating liquid water from the recirculation gas. In addition, this base body is equipped with a collecting section for collecting the separated liquid water. In addition, the base body has at least one gas inlet upstream of the cyclone section for the inlet of recirculation gas and a gas outlet downstream of the cyclone section for

Outlet of recirculation gas on.

The core idea according to the invention is now to design the separating device so that it can be integrated into a recirculation section of a fuel cell system. This allows recirculation gas, that is to say exhaust gas from the fuel cell stack, which is to be fed back into the feed gas to the fuel cell stack in a recirculating manner, to be dried and / or to be freed from liquid water. The recirculation gas is in particular anode exhaust gas, which is to be at least partially fed to an anode feed gas in a recirculating manner. It is thus possible to combine this recirculation function with the drying function and / or

Dehumidification function for this recirculation gas to combine constructively and

to reduce.

In the context of the invention, liquid water is understood to mean, in particular, product water and condensation water. In other words, liquid water includes product water and

Condensation.

Another core idea according to the invention is based on the use of a cyclone section with a spiral cross-section. A cyclone section with a spiral cross-section is to be understood as meaning that the recirculation gas is set in a rotational movement along the spiral cross-section. The cyclone section can additionally have a conical longitudinal extension in order to further intensify the cyclone effect. In principle, however, it is also sufficient if the spiral cross-section of the cyclone section has a cylindrical or essentially cylindrical configuration, in order to remove the liquid water components from the gaseous remainder of the

Separate recirculation gas.

According to the invention, it is now possible for moist recirculation gas, in particular anode exhaust gas, to penetrate into the base body via the gas inlet and to be fed to the cyclone section. The spiral-shaped cross-section in the cyclone section provides a corresponding guidance of the recirculation gas, which sets the recirculation gas in a rotational movement along this spiral-shaped cross-section. Through this rotational movement, the cyclone principle provides a separation of liquid water particles, which are then moved downwards along a direction of gravity. After this separation by the cyclone principle, the remaining recirculation gas, which can now also be referred to as dried recirculation gas, can leave the cyclone section again via the gas outlet. In other words, moist recirculation gas is introduced into the base body via the gas inlet and via the gas outlet

dried and / or dehumidified recirculation gas applied again.

In order to ensure further use or targeted discharge of the collected and separated liquid water, a collecting section is additionally provided within the base body. This catchment section is

preferably in the installed position in the direction of gravity below the

As can be seen from the preceding explanation, a high degree of integration can now be achieved. The separating functionality for drying the recirculation gas through the cyclone section is designed to be particularly simple and compact. In addition, this drying functionality is combined with the recirculation functionality, since after the drying step in the cyclone section the recirculation gas can be fed back to an anode feed gas as a recirculation gas in the dried state. The high degree of integration can be seen in particular from the fact that the cyclone section and the collecting section for the separated liquid water are integrated in a common base body, so that the compactness of such a body

Separation device has been increased even further.

The compact and simple design of the separating device in the common base body makes it possible to integrate this part of a recirculation section, which is formed by the separating device, into a central media supply of a fuel cell system, for example. The high degree of integration becomes even clearer if the fuel cell system has two or more fuel cell stacks for which one and the same central media supply and / or one and the same separating device according to the invention can be used.

It can bring advantages if, in a separating device according to the invention, the base body has a first base body component, which at least partially forms the cyclone section, and a second base body component, which forms the collection section at least partially. In particular, the cyclone section is complete or in

Essentially completely formed in the first main body component. Likewise

It is also advantageous if, in a separating device according to the invention, the cyclone section extends along a cyclone axis which is aligned along an assembly axis of the first base body component and the second base body component. Such a cyclone axis is defined in particular by the spiral-shaped cross section of the cyclone section. For example, such a cyclone axis can represent the central spiral axis of such a spiral cross-section. The cyclone axis can also be understood as an axis of rotation for a conical and / or cylindrical cyclone section. The correlation of this embodiment for the cyclone axis and the assembly axis further simplifies the assembly of the base body. The cyclone axis and the assembly axis are preferably aligned parallel or essentially parallel, in particular coaxially and / or essentially coaxially to one another.

This allows the second base body component to be incorporated into the first base body component

Base body components of the base body.

Further advantages can be achieved if, in a separating device according to the invention, the first base body component has the gas inlet and the second base body component has the gas outlet. This means that the gas inlet and gas outlet are divided into different main body components. However, it is fundamentally also conceivable that the gas inlet and gas outlet are arranged in one and the same base body component, in particular in the first base body component, in order to make this first base body component easier to manufacture, since no further base body components have to be taken into account with regard to manufacturing inaccuracies. In other words, the relative positions of the gas inlet and gas outlet are advantageously made available in this way simply and inexpensively in a single base body component.

It is also advantageous if, in a separating device according to the invention, the base body has at least one second gas inlet upstream of the cyclone section for an inlet of recirculation gas, in particular from a second fuel cell stack. As has already been explained, a separating device according to the invention can provide the advantages of integration and reduced complexity, in particular also in the case of highly complex fuel cell systems with several fuel cell stacks. It is now conceivable that recirculation gas is to be returned to the anode supply gas in a recirculating manner not only from one fuel cell stack, but also from a second or further fuel cell stack. in such a complex fuel cell system there is in particular one

central supply with anode supply gas advantageous, which after the central

specific gas inlet provided.

Further advantages can be achieved if, in a separating device according to the invention, the gas inlets each have an inlet direction which is oriented identically or essentially identically. If, according to the preceding paragraph, two or more gas inlets are provided, then these gas inlets guide the recirculation gas along the inlet direction into the cyclone section. Even with a single gas inlet, it is advantageous if this inlet direction is aligned along a wall of the spiral-shaped cross section of the cyclone section in order to further support the rotation function for the separation functionality in the cyclone section. If two or more gas inlets are provided, these inlet directions are preferably aligned in the same way, in particular in or essentially in a common plane. This supports the tangential introduction of the individual recirculation flows and in this way the separation functionality in the cyclone section. This is particularly the case when the gas inlets are provided at different height positions of the cyclone section. The inlet direction preferably defines the same direction with the same or essentially the same radial distance

with respect to the cyclone axis of the cyclone section.

It can also be advantageous if, in a separating device according to the invention, within the base body, at least one sensor element for determining a sensor parameter, in particular one of the following,

is arranged:

- pressure sensor,

- temperature sensor,

- flow sensor,

- gas sensor,

- humidity sensor,

- liquid level sensor.

The above list is not an exhaustive list. A pressure sensor makes it possible in particular in the gas inlet, in the cyclone section and / or in the gas outlet, to determine the corresponding internal pressure and to make it available to a further (essential) control function for the fuel cell system. In the same way, it is also possible to determine the corresponding individual temperatures via temperature sensors within the gas inlet, the cyclone section and / or the gas outlet and / or also in the collecting section. The same applies to correspondingly arranged flow sensors for flow velocities and / or gas sensors for the detection of certain gas components in a quantitative and / or qualitative manner. The moisture, in particular in the gas inlet and / or in the gas outlet, can also be detected with a sensor in order to be able to monitor the drying function and also the drying success within the separating device. With the aid of an integrated liquid level sensor, the liquid level can be monitored in the collecting section, in particular in a collecting container provided therein, in order to be able to ensure a defined discharge of separated liquid water. In this embodiment, the high degree of integration is shown again, since a large number of sensor elements are not only in the separating device, but in particular in the associated base body

are integrated.

It is also advantageous if, in a separating device according to the invention, the base body has a collecting container for collecting the separated liquid water downstream of the cyclone section, in particular as part of the collecting section. Such a collecting container allows intermediate storage or buffering of the collected liquid water. The corresponding drainage of the collected liquid water is to the environment or to

Further use within the fuel cell system is possible. Preferably the

Collecting section or the collecting container in the collecting section

and thus in particular in the associated separate second housing component of the

Integrated body. The second housing part can due to its geometry

can be flexibly adapted to the installation position so that it is independent of a

To be fuel cell stack position.

It is also advantageous if, in a separating device according to the invention, an introduction device, in particular in the form of an injector device and / or an ejector device, is arranged downstream of the gas outlet for introducing the recirculation gas from the gas outlet into an anode feed section of the fuel cell system. Such an introduction device can be part of the base body or a separate component. An injector device allows a pressurized, dried recirculation gas to be introduced into an anode feed gas or a corresponding mixing section. An ejector device allows the dried recirculation gas to be sucked in through the negative pressure developed in the area of the anode feed gas and fed to the anode feed gas from the gas outlet. Mixing with fresh anode gas is significantly improved in this way and, in particular, passive recirculation can be made available. Of course, it is also possible to integrate an additional shut-off valve in order to stop or switch on the recirculation completely and / or to control it quantitatively.

Further advantages can be achieved if, in a separating device according to the invention, an outlet valve is arranged downstream of the gas outlet, in particular in front of an introduction device. Such an outlet valve can also be referred to as a purge valve and is opened in particular during a starting process of the fuel cell system. The influence of such an outlet valve on the regular operation of the fuel cell system and in particular on the function of the recirculation of the recirculation gas is reduced or even minimized in this way. This is done by ensuring that the general flow direction of the recirculation is not disturbed during a purge process. In the context of the invention, an outlet valve is understood to mean a so-called purge valve, that is to say a gas outlet, for reducing N2

in the recirculation path.

10733

The present invention also relates to a fuel cell system,

having:

- At least one fuel cell stack with an anode section and

a cathode section,

an anode supply section for supplying anode supply gas

the anode section,

a cathode supply section for supplying cathode supply gas

to the cathode section, - an anode discharge section for discharging anode exhaust gas, - a cathode discharge section for discharging cathode exhaust gas,

- A recirculation section for recirculating at least part of the anode exhaust gas as recirculation gas from the

Anode discharge section into the anode feed section.

At least one separating device according to the invention is arranged in the recirculation section. A fuel cell system according to the invention thus brings the same advantages as they are detailed with reference to a

separating device according to the invention have been explained.

11733

Fuel cell stack can be further improved and in particular reduced.

It can also be advantageous if, in a fuel cell system according to the invention, the separating device is integrated into a central media supply unit, in particular for a plurality of fuel cell stacks. Such a central media supply unit can in particular be provided at a central positioning of the fuel cell system. The media supply unit thus allows a central connection, in particular to the anode supply gas, for example a corresponding hydrogen supply. Because the separating device is now also integrated into this central media supply unit, the advantages according to the invention with regard to reduced installation space and reduced costs can be achieved in an improved manner. This is especially true if the fuel cell system has several

Has fuel cell stack.

Another object of the present invention is a method for assembling a separating device according to the invention, comprising the following steps:

- forming the cyclone section,

- formation of the collecting section,

By designing a separating device according to the invention, a method according to the invention has the same advantages as have been explained in detail with reference to a separating device according to the invention. The formation of the cyclone section and / or the collecting section can be made available, for example, by an injection molding process. However, in the case of complex geometries, other training methods, for example three-dimensional printing methods, are also conceivable. The joining step includes, in particular, sliding different housing components into one another in order to form a common base body.

Further advantages, features and details of the invention emerge from the following description, in which exemplary embodiments of the invention are described in detail with reference to the drawings. The features mentioned in the claims and in the description can each be essential to the invention individually or in any combination. Show it

schematic:

Fig. 1 shows an embodiment of an inventive

Separating device on a fuel cell system, FIG. 2 the embodiment of FIG. 1 in a first cross section,

3 shows the embodiment of FIGS. 1 and 2 in a second

Cross-section,

4 shows a first basic body component in a first cross section,

FIG. 5 shows the first basic body component of FIG. 4 in a perspective illustration,

6 shows a second basic body component in a perspective illustration,

7 shows the second main body component of FIG. 6 in a top view,

Fuel cell system and

9 shows a further embodiment of an inventive

Fuel cell system.

FIG. 1 shows schematically how, in the case of a fuel cell system 100, a separating device 10 can be integrated into a central media supply unit 180. This is to be understood in particular in connection with FIGS. 8 and 9 and the fuel cell systems 100 illustrated therein. In this embodiment of FIG. 1, a base body 20 can be seen which has a first base body component 20a and a second base body component 20b. Recirculation gas RG can be introduced from two separate fuel cell stacks 110 via two separate gas inlets 22. In the first housing component 20a, a cyclone section 30 (not shown in FIG. 1) is formed, which allows the separation of liquid water into the outlet section 40 in the second base body component 20b. Here, too, after the gas outlet 24, an introduction device 170 is provided as an ejector, which allows the recirculation gas to be combined with fresh anode feed gas, in order to subsequently divide the anode feed section 120 to the individual fuel cell stacks 110

allow.

In addition, an outlet valve 60 can be seen in FIG. 1 as a purge valve on the upper side of the base body 20. With a sensor element 50, it is also possible here to monitor the liquid level in the collecting section 40 of the second base body component 20b and to open an outlet for the liquid water W via a drain valve 44, which can also be referred to as a drain valve

allow.

Figures 2 and 3 show the functionality of the cyclone action for the separation of liquid water W. Via the two gas inlets 22, recirculation gas RG is introduced into the first base body component 20a along the inlet directions ER. This creates a tangential inlet direction ER to the spiral cross section of the cyclone section 30, which can be seen particularly well in FIG. The introduced recirculation gas RG is set in a rotational movement and through this

Rotational movement via the cyclone functionality liquid water W to the

to be fed to one or more fuel stacks 110.

In addition, FIG. 4 shows the first base body component 20a in the dismantled state. In particular, the cyclone axis ZA, which at the same time also forms the assembly axis MA, can be seen clearly here. The gas inlets 22, which are aligned in parallel, can also be seen clearly in FIG. In conjunction with the illustration in FIGS. 6 and 7, the assembly effect is to be explained. The second base body component 20b is also designed with an assembly axis MA and here with an identical cyclone axis ZA, so that the second base body component 20b can be inserted into the first base body component 20a from below. This movement takes place along the assembly axes MA until a corresponding sealing line of the two base body components 20a and 20b touches and in this way seals the interior of the base body 20.

FIG. 8 shows schematically how a fuel cell system 100 according to the invention can be designed. Anode feed gas is fed to the anode section 112 of the fuel cell stack 110 via the anode feed section 120. Likewise, outside air as cathode feed gas is fed to the cathode section 114 via the cathode feed section 140 here via a compressor. After the reaction in the fuel cell stack 110, the anode exhaust gas can be removed from the anode section 112 via the anode removal section 122. In a similar manner, the cathode exhaust gas is discharged from the cathode section 114 via the

Cathode discharge section 142. In FIG. 8 it can also be seen that now

at least a portion of the anode off-gas via the recirculation section 130 via

a separating device 10 according to the invention and the introduction device 170

can be fed back to the anode feed section 120. About this

The drain valve 44 shown can discharge the separated liquid water W

and discharged, or else for further use in the fuel cell system 100

are fed.

FIG. 9 shows a further development of the embodiment of FIG. 8, the fuel cell system 100 here having two fuel cell stacks 110. In order to supply them with the appropriate anode feed gas, the anode feed section 120 is divided between the two anode sections 112 of the two fuel cell stacks 110. In the same way, a design in double division is also provided for the two fuel cell stacks 110 for the cathode feed section 140 as well as the anode discharge section 122 and the cathode discharge section 142. Here it can be seen again how the recirculation sections 130 of the two fuel cell stacks 110 are brought together in the common separating device 10 in order to then feed the recirculation gas in the common part of the anode feed section 120

Mix RG with fresh anode feed gas.

The above explanation of the embodiments describes the present invention exclusively in the context of examples. Of course, individual features of the embodiments can be freely combined with one another, insofar as it is technically sensible, without going beyond the scope of the present invention

leaving.

List of reference symbols

10 Separation device

20 basic bodies

20a first base body component 20b second base body component 22 gas inlet

24 gas outlet

30 cyclone section

40 catchment section

42 collection container

44 Drain valve

50 sensor element

60 exhaust valve

100 fuel cell system 110 fuel cell stack 112 anode section

114 cathode section

120 anode feed section 122 anode discharge section 130 recirculation section 140 cathode feed section 142 cathode discharge section 170 introduction device

180 central media supply unit

W water

RG recirculation gas ZA cyclone axis

MA assembly axis ER inlet direction

17733

Claims (1)

Claims 1. Separating device (10) for separating liquid water (W) from a recirculation gas (RG) in a recirculation section (160) of a fuel cell system (100), comprising a base body (20) with a cyclone section (30) with a spiral cross-section for separating liquid water (W) from the recirculation gas (RG) and a collecting section (40) for collecting the separated liquid water (W), the base body (20) having at least one gas inlet (22) upstream of the cyclone section (30) for the inlet of recirculation gas ( RG) and a gas outlet (24) downstream of the cyclone section (30) to the outlet of Has recirculation gas (RG). 2. Separating device (10) according to claim 1, characterized in that the base body (20) has a first base body component (20a) which forms the cyclone section (30) at least in sections, and a second base body component (20b) which has the collecting section (40 ) trains at least in sections. 3. Separating device (10) according to claim 2, characterized in that the cyclone section (30) extends along a cyclone axis (ZA), which along an assembly axis (MA) of the first base body component (20a) and of the second main body component (20b) is aligned. 4. Separating device (10) according to one of claims 2 or 3, characterized in that the first base body component (20a) is the gas inlet (22) and the second main body component (20b) has the gas outlet (24). 5. Separating device (10) according to one of the preceding claims, characterized in that the base body (20) has at least one second gas inlet (22) upstream of the cyclone section (30) for an inlet of recirculation gas (RG), in particular of a second Fuel cell stack (110). 7. Separating device (10) according to one of the preceding claims, characterized in that within the base body (20) at least one sensor element (50) for determining a sensor parameter, in particular one of the following, is arranged: - pressure sensor - temperature sensor - flow sensor - gas sensor - humidity sensor - liquid level sensor 8. Separating device (10) according to one of the preceding claims, characterized in that the base body (20) downstream of the cyclone section (30), in particular as part of the collecting section (40), a collecting container (42) for collecting the separated liquid water ( W) having. 9. Separating device (10) according to one of the preceding claims, characterized in that downstream of the gas outlet (24) an introduction device (170), in particular in the form of an injector device and / or an ejector device, for introducing the recirculation gas (RG) from the gas outlet (24) into an anode feed section (120) of the Fuel cell system (100) is arranged. 10. Separating device (10) according to one of the preceding claims, characterized in that downstream of the gas outlet (24), in particular in front of an introduction device (170), an outlet valve (60) is arranged. (W). 12. Fuel cell system (100), having - At least one fuel cell stack (110) with an anode section (112) and a cathode section (114), - an anode supply section (120) for supplying anode supply gas to the anode section (112), - a cathode supply section (140) for supplying Cathode feed gas to the cathode section (114), - an anode discharge section (122) for discharging anode exhaust gas, - a cathode discharge section (142) for discharging cathode exhaust gas, - a recirculation section (130) for recirculating at least part of the anode exhaust gas as recirculation gas (RG) from the anode discharge section (122) into the anode supply section (120), wherein in the recirculation section (130) at least one separating device (10) having the features of one of claims 1 to 11 is arranged. 13. Fuel cell system (100) according to claim 12, characterized in that at least two, in particular identical or substantially identical, fuel cell stacks (110) are provided, the separating device (10) at the end of the two recirculation sections (130) as a common separating device (10) ) for both recirculation gases (RG) the at least two fuel cell stacks (110) is arranged. 14. Fuel cell system (100) according to one of claims 12 or 13, characterized in that the separating device (10) in a central media supply unit (180), in particular for several Fuel cell stack (110), is integrated. 15. A method for assembling a separating device (10) having the features One of claims 1 to 11, comprising the following steps: - forming the cyclone section (30), - forming the collecting section (40), - Joining the cyclone section (30) and the collecting section (40) to form the base body (20) with the formation of a fluid-communicating connection between the cyclone section (30) and the collecting section (40).