DE102022125251A1 - Separation device for separating liquid water from an exhaust gas in an exhaust gas section of a fuel cell system - Google Patents

Abstract

The present invention relates to a separating device (10) for separating liquid water (W) from an exhaust gas (A) in an exhaust gas section of a fuel cell system (100), having a base body (20) with a separating section (30) for separating liquid water ( W) from the exhaust gas (A) 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 separating section (30) for the inlet of exhaust gas (A) and has a gas outlet (24) downstream of the separating section (30) for discharging exhaust gas (A), characterized in that the separating section (30) has a curved guide wall (32) for receiving and guiding the exhaust gas (A) from the gas inlet (22 ) and the curvature of this guide wall (32) reduces from an initial curved section (33) away from the gas inlet (22) to a final curved section (34).

Description

The present invention relates to a separating device for separating liquid water from an exhaust gas in an exhaust gas section of a fuel cell system and a fuel cell system with such a separating device.

It is known that the operation of fuel cell systems produces exhaust gas which, among other things, also contains liquid water in the form of droplets. It is also known that this droplet-shaped water should be separated from the exhaust gas, on the one hand, to keep the exhaust gas as dry as possible and, on the other hand, to protect components from increased mechanical stress caused by the effects of water droplets. This is usually ensured by the fact that separating devices are provided as water separators in the exhaust gas sections of a fuel cell system, which separate the liquid water from the gaseous exhaust gas and remove it or at least collect it.

A disadvantage of the known solutions is that the separating function for the water to be separated is usually accompanied by a high pressure drop. This is due in particular to the fact that a cyclone with a centrally arranged outlet pipe is often used. In this concept, the exhaust gas is continuously accelerated and causes high flow velocities and losses at the diversion to the smallest diameter of the outlet. Systems are also used to guide the exhaust gas in a labyrinthine manner in such a way that the water is separated.

It is the object of the present invention to at least partially eliminate the disadvantages described above. In particular, it is the object of the present invention to enable water to be separated from an exhaust gas in a fuel cell system in a cost-effective and simple manner with the lowest possible pressure loss.

The above object is achieved by a separating device having the features of claim 1 and a fuel cell system having the features of claim 15. Further features and details of the invention result 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 vice versa, so that the disclosure of the individual aspects of the invention is or can always be referred to alternately.

According to the invention, a separating device is used to separate liquid water from an exhaust gas in an exhaust gas section of a fuel cell system. For this purpose, such a separating device has a base body with a separating section for separating liquid water from the exhaust gas. In addition, a collecting section for collecting the separated liquid water is provided. The base body has at least one gas inlet upstream of the separating section for inlet of exhaust gas and one gas outlet downstream of the separating section for outlet of exhaust gas. According to the invention, the separating device is characterized in that the separating section has a curved guide wall for receiving and guiding the exhaust gas from the gas inlet, the curvature of this guide wall reducing from an initial curved section away from the gas inlet to an end curved section.

The at least one gas inlet is preferably designed with a narrow configuration in the radial direction, so that an elongated opening is formed. Consequently, in particular all gas inlets are formed on edge, ie they are narrow in a radial direction and long or large in the vertical direction.

The core idea according to the invention is based on a separation principle, which will also later be described as the reverse cyclone separation principle. This means that the exhaust gas is introduced into the separating section from the gas inlet together with the liquid water droplets still present. The separating section is now formed with the guide wall in such a way that it receives the exhaust gas and guides it along the guide wall. This type of guidance means that the direction of flow of the exhaust gas that is introduced is deflected and the direction of flow of the exhaust gas is directed by the guide wall. The guide wall is designed in such a way that the initial curved section is fitted directly after the gas inlet or shortly after the gas inlet. This initial curved section has a significantly greater curvature in relation to the final curved section, which will be explained later, so that the inflowing exhaust gas is strongly deflected here. Strong deflection of the exhaust gas, which is still flowing in at high flow speed, means that the water droplets that are entrained are pressed outwards against the guide wall by centrifugal force. In other words, the water droplets are separated from the exhaust gas to the outside by the centrifugal force as the separating force. Due to the fact that the exhaust gas and the separated water droplets flow along the guide wall as the curvature of this guide wall decreases, the influence of the change in flow direction will correspondingly also decrease. With the decrease in influence, the flow speed of the inflowed exhaust gas slows down, so that entrainment of waterdrops after being separated at the initial bend portion is reduced. The core idea of the present invention is therefore based on the fact that a strong deflection at the initial curved section compared to the later course of the guide wall provides a strong separating function, with the separation of the water droplets made available as a result of continuing through the reduced curvature to the End-curvature section is maintained. In particular, this means that this separation functionality can be performed without labyrinthine elements or a siphon. Since the separation functionality here is based essentially exclusively on speed differences and the redirection of the flow of the exhaust gas, this means that a very low pressure drop can be achieved when using this separation method.

The separation of the water droplets in liquid form from the exhaust gas takes place in the manner described by centrifugal force and the deflection of the exhaust gas. The further conveyance of the separated water droplets takes place in particular through the force of gravity along the gravitational direction. Thus, the separating device is preferably equipped with a defined installation position in the fuel cell system with a correspondingly correlated direction of gravity. The separated water can now be transported with the help of gravitation along this direction of gravity into the collecting section of the base body and collected there. Further transport, discharge from the collecting section or intermediate storage in this collecting section for the separated water can also take place, and this can preferably be promoted by the arrangement of drainage aids.

In addition to the fundamental change in the curvature over the course of the guide wall, a three-dimensional routing of the exhaust gas is preferably desired. As will also be explained in more detail later, the exhaust gas is preferably guided along the direction of gravity from top to bottom, so that from the gas inlet, the exhaust gas moves in a spiral manner with increasing curvature from the initial curved section to the final curved section. The speed decreases and the separating function for the separated water is maintained.

In addition, there is preferably a separation between the gas inlet and the gas outlet by the separating section and in particular by the guide wall in order to effectively avoid a bypass of inflowing exhaust gas past the separating section to the gas outlet.

It should also be pointed out that the separating section for this described functionality of the changing curvature can be designed in different ways. So it is conceivable that the separating section is tubular or at least partially tubular along a helical or spiral line and provides an enclosing guiding functionality for the exhaust gas. In principle, however, it is also possible for this guide wall to be designed as a one-sided wall or dividing wall, so that the guide functionality can be adjusted by the flow conditions in the separating section, in particular along the direction of gravity. Combinations of closed and open separating sections are also fundamentally conceivable within the scope of the present invention.

It can be advantageous if, in a separating device according to the invention, the initial curved section of the guide wall deflects the guided exhaust gas in the range between at least 30° and at most 360°. Such a very strong curvature thus leads to a continuous change of direction or even to a complete deflection of the introduced exhaust gas by 360°. In particular due to the high flow velocity directly at or after the gas inlet, this leads to high droplet velocities and a very strong separation functionality. In addition, the exhaust gas is also pushed outwards and there is a widening transverse to the flow direction on the guide wall, a strong reduction in the speed of the exhaust gas is accompanied by this widening, so that the separation function of the water that has already been separated is maintained with a high degree of certainty. In other words, after the initial bend section, the guide wall opens the flow cross-section much more than would ever be possible in a straight tubular diffuser without separation.

There can be advantages if, in a separating device according to the invention, the guide wall extends downwards, from the initial curved section to the final curved section, away from the gas inlet, in particular along a direction of gravity. This means that the exhaust gas is conveyed in the form of a roller around the direction of gravity and the separated water is conveyed by the effect of gravita tion force is conveyed out of this rolling flow. The aim is that no unnecessary braking occurs due to opposing flow conditions between the dry exhaust gas and the separated water. This leads to a further improvement in the flow conditions in the interior of the separating device and in particular in the separating section.

It is also advantageous if, in a separating device according to the invention, the flow cross section of the separating section increases from the initial curved section to the final curved section. This means that not only is the curvature reduced and, as a result, a speed reduction of the exhaust gas takes place, but this speed reduction can also be further intensified by widening the flow cross section. The combination of the widening of the curvature and the widening flow cross section thus leads to a mutually reinforcing separating effect and securing effect for the separated water. The aim is that the gravitational effect increasingly moves the wall films and not the flow forces from the exhaust gas flow at high speed.

It is also advantageous if, in a separating device according to the invention, the separating section is designed without a siphon section. Separating devices with a siphon have a high pressure loss, which is why the separating functionality according to the invention is made available in order to design the complete separating device without such a siphon. This leads to the great advantage already mentioned at the outset of a significantly lower pressure loss of a separating device according to the invention compared to one with a siphon. The separating effect is thus achieved here independently of a siphon through the speed reduction due to the curvature variation.

It is also advantageous if, in a separating device according to the invention, the separating section is designed as an inverted cyclone separator. This means a conical or essentially conical configuration, which takes into account the curvature conditions described in each case and preferably also the conditions of the flow cross section described, in order to design the speed profile with the directional profile of the flow of the exhaust gas with the separation functionality according to the invention for separating the liquid water.

It is also advantageous if, in a separating device according to the invention, the curvature of the guide wall decreases from the initial curved section to the final curved section without kinks, in particular continuously or essentially continuously. This leads in particular to a continuous decrease in the flow velocity and also preferably to a continuous change in the direction of the exhaust gas. Both lead to a particularly uniform flow and, in particular, prevent the formation of vortices and the shedding of vortices. This preferably leads to the entire wall film flow remaining largely or even completely in laminar flow conditions within the separating section, so that turbulent flow areas are avoided or at least reduced. The smoothest possible flow within the separating section, in turn, means that the separated water adheres to the guide wall of the separating section as a water film with a higher probability and greater certainty (adhesion), remains and can be discharged into the collecting section separated from the dried exhaust gas in the manner described . For the purposes of the present invention, dried exhaust gas is understood to be exhaust gas from which at least some liquid water has been removed by the separation principle described and which is therefore at least essentially free of water droplets. In particular, dried exhaust gas still has a residual moisture according to this definition, so that the present invention relates to the separation of liquid, droplet-shaped water free or essentially free of condensation drying.

It is also advantageous if, in a separating device according to the invention, the guide wall has at least one guide receptacle for receiving and removing water films, in particular at least in the curved end section. While the basic quality according to the invention is already ensured by the fact that a speed reduction of the exhaust gas is achieved through the variation in curvature and in particular also a variation in the flow cross section, securing the separated water against being entrained by the dried exhaust gas can be further improved by such a guide receptacle . In the simplest case, these can be grooved or rib-shaped elements that convey the water along the direction of gravity, i.e. the direction of gravity by gravitational force, and protect it against being entrained by the dried exhaust gas due to their geometric design. Lateral channel receptacles or pipe receptacles are also conceivable, which, as guide receptacles, receive the water, for example through a receptacle slot, and are accordingly still safe erer can dissipate separately from the dried exhaust gas.

It is also advantageous if, in the case of a separating device according to the preceding paragraph, a guide receptacle is aligned at least in sections along or essentially along the direction of gravity. As has already been explained, it is advantageous if, for the removal of the separated water from the then dried exhaust gas, this removed and separated water is moved into the collecting section by gravitational force. In order to now avoid one siphon section as effectively and finally as possible, this guide receptacle is aligned along or essentially along the direction of gravity, so that the maximum effect of the gravitational force is achieved for discharging the separated water.

It is also advantageous in a separating device of the two preceding paragraphs if the at least one guide receptacle has a non-return device, in particular in the form of at least one non-return device lip, to prevent the water that has been taken up from running back. As has already been explained, a strong separating function can be provided by a strong curvature variation in the initial curved section of the guide wall, so that a large part of the liquid water can be separated from the introduced exhaust gas over a very short distance along the guide wall. Thus, after a short distance after this separation, this already separated water can also be taken up through a corresponding slot or an inlet opening in the guide receptacle. In order to prevent the undesired entrainment of the separated water in the dried exhaust gas even more reliably for further conveyance, a backstop can be provided which, for example, lip-shaped or scored due to the geometry, prevents such entrainment even more effectively and thus further strengthens the functionality according to the invention. The water can thus be conveyed into the guide receptacle in separated form, in particular pressed, but cannot escape again against this backstop, or only partially, or only in very improbable cases.

There are advantages if, in a separating device according to the invention, the collecting section has a non-return element for preventing the collected water from flowing back into the separating section. This is also a backstop, which is already effective when the water is already in the collection section. Corresponding labyrinth formations or walls can be provided here in order to prevent the separated water from flowing back or running back out of the collecting section.

It can also be advantageous if the base body in a separating device according to the invention has at least two gas inlets for the inlet of exhaust gas in the separating section, the two gas inlets being arranged at different heights relative to a base body axis of the base body. This can be different exhaust gas sections of a fuel cell stack, for example. In the case of larger fuel cell systems with a plurality of fuel cell stacks, a plurality of gas inlets from the same section of the respective other fuel cell stack can also be introduced into a common separating device. The gas inlets are preferably arranged at different heights, but at the same or essentially the same circumferential position and/or at the same or essentially the same radial position, so that identical or essentially identical separating functions for separating the water are provided for both gas inlets and a mutual influence by the offset in height direction is avoided.

There are further advantages if, in the case of a separating device according to the invention, the base body is produced using a built-up process. This can be a so-called 3D printing process or sintering process, for example. This leads in particular to the fact that even very complex flow geometries can be produced in a cost-effective and simple manner, in particular for the guide wall.

It is also advantageous if, in a separating device according to the invention, the gas inlet extends from a side wall of the separating section into the separating section. This ensures that an expansion of the flow cross sections after the gas inlet is avoided and a clean transfer, in particular in a laminar manner, sets uniform flow conditions after the gas inlet when transferring to the guide wall. In particular, this avoids turbulence when the exhaust gas is introduced and, moreover, preferably avoids mixing with already dried exhaust gas after it has been guided through the guide wall.

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. The anode section has an anode supply section for supplying anode supply gas and an anode discharge section for discharging anode exhaust gas. The cathode section has a cathode supply section for supplying cathode supply gas and a cathode discharge section for discharging cathode off-gas. Furthermore, the fuel cell system is equipped with a separating device according to the present invention, the gas inlet of which is connected in fluid communication with the anode discharge section or the cathode discharge section. A fuel cell system according to the invention thus brings with it the same advantages as have been explained in detail with reference to a separating device according to the invention. The separated off-gases from anode off-gas and cathode off-gas can, for example, be admixed to a recirculation gas section for recirculation into the anode feed section.

A number of separating devices for different exhaust gas sections of the fuel cell system can also be operated separately from one another. In the case of recirculation, the gas outlet of the separating device is preferably formed with an injector device or is connected to it in fluid communication in order to provide an injector functionality for the recirculation.

• 1 eine Ausführungsform einer erfindungsgemäßen Separiervorrichtung in seitlichem Querschnitt,
• 2 die Ausführungsform der 1 in einem Querschnitt in Draufsicht,
• 3 eine schematische Darstellung eines Trennabschnitts in Draufsicht,
• 4 die Ausführungsform der 3 in seitlicher Darstellung,
• 5 eine weitere Ausführungsform eines Trennabschnitts mit einer Führungsaufnahme,
• 6 eine Detaildarstellung der Ausführungsform der 5,
• 7 eine weitere Ausführungsform einer erfindungsgemäßen Separiervorrichtung,
• 8 eine Ausführungsform eines erfindungsgemäßen Brennstoffzellensystems.

Further advantages, features and details of the invention result from the following description, in which exemplary embodiments of the invention are described in detail with reference to the drawings. They show schematically:

• 1 an embodiment of a separating device according to the invention in lateral cross section,
• 2 the embodiment of 1 in a cross section in top view,
• 3 a schematic representation of a separating section in plan view,
• 4 the embodiment of 3 in side view,
• 5 a further embodiment of a separating section with a guide receptacle,
• 6 a detailed representation of the embodiment of FIG 5 ,
• 7 a further embodiment of a separating device according to the invention,
• 8th an embodiment of a fuel cell system according to the invention.

The 1 and 2 show schematically how a separating device 10 can be constructed. This is essentially divided into two core sections, namely the separating section 30 and the collecting section 40 . Exhaust gas A can enter the separating section 30 via a gas inlet 22 and the water W can be separated from the exhaust gas A there with the aid of the separating function. Along the direction of gravity SR, in 1 down, this separated water can W (in 1 not shown in detail) are discharged down into the collecting section 40. A corresponding reservoir, a collecting volume or the like can be provided there in order to receive and store the separated water W or also to carry it on. The exhaust gas A dried in this way now goes into the left area and thus leaves the separating section 30 in order to flow in a dried manner to the gas outlet 24 and to be made available again to the further system or to be discharged to the environment.

Based on 2 the functionality of this separation of the water W from the exhaust gas A is shown schematically. The exhaust gas A flows through the gas inlet 22 and projects into the separating section 30 . In order to avoid turbulence of the exhaust gas A with a high degree of probability, the gas inlet 22 with its gas inlet wall 23 projects beyond the side wall 31 of the separating section 30 . This ensures that the exhaust gas A is applied cleanly to the guide wall 32 when it exits from the gas inlet 22 . Here, shown partially elliptical, the guide wall 32 is designed in such a way that the curvature now widens slowly. A spiral design is also conceivable in order to avoid an increased curvature after 90°. This figure also clearly shows that a cylindrical flow forms, which flows out of the separating section below and/or above the gas inlet 22 through a free space in the guide wall 32 . The other separation function is particularly in the following with reference to the 3 and 4 explained in more detail.

So show these 3 and 4 well, once in top view according to the 3 and once in lateral representation according to 4 , a schematic possibility of a separation functionality. This is shown here as essentially tubular, but it also works identically with a pure wall design, such as that shown in the 1 and 2 show. In 3 is shown in a plan view how the exhaust gas A flows into the gas inlet 22 and now rests against the guide wall 32 . In the initial curved section 33 there is a strong deflection, here for example by approximately 120°. The centrifugal force carries the water W outwards in the form of drops and presses it against the wall. About the further course shows the 4 that the dried exhaust gas A is guided downward along the direction of gravity. The water W is also conveyed downwards along the direction of gravity SR by the force of gravity. Because the water W is now already on the side wall of the guide wall 32, a water film is formed, as is shown schematically in FIG 4 is shown pushed down by the direction of gravity SR. This ensures that the separated water W can now be introduced into the collecting section 40 . The 3 12 shows how the curvature increases from the initial curvature portion 33 to the final curvature portion 34, with the flow velocity of the inflowing exhaust gas A correspondingly decreasing. In addition, the flow cross section increases along the guide wall 32, which additionally reduces the flow rate of the exhaust gas A in its dried form. Both have the effect that a reduced velocity of the exhaust gas A prevents the separated water W from being entrained or at least reduces this risk. The separated water W can now be received in the collecting section 40, this in the embodiment of FIG 4 is equipped with a backstop element 42. This is a labyrinthine wall here, which prevents water W that has entered the collecting section 40 from running back into the separating section 30 . In principle, any cross-sectional shape of the tube is conceivable. Cross-sections with a greater height extension than radial width, which are significantly greater than those in 3 and 4 indicated relations can be executed.

Based on 5 and 6 it is explained again how the separation functionality can be further increased and improved. So here after a little more than half of the circumference of the guide wall 32 a guide receptacle 36 is formed in the shape of a slot. Water, which has now been pressed against the guide wall 32 by the centrifugal force after entering from the gas inlet 22, is now entrained along this guide wall with the exhaust gas A and in the plane of the drawing 5 backwards, ie downwards along the direction of gravity SR. As soon as the slit of the guide seat 36 is reached, the separated water W enters this guide seat 36 and is pushed down by gravity along the gravity direction SR (in 5 into the plane of the drawing) to the collecting section 40 out. The 6 shows how this guide receptacle 36 can be further secured against the separated water W running back. Two backstops 37 are shown here in a lip-shaped manner, which are intended to hold the water W within the guide receptacle 36 with greater certainty after it has entered. As shown, a narrowing but also a widening design of this gap can be advantageous as a compromise between hydraulic and manufacturing aspects.

The 7 shows a development of the embodiment of FIG 1 . However, this is shown here with two gas inlets 22 which are offset from one another in the same circumferential position and the same radial position in the direction of gravity SR. In addition, the separating section 30 is designed to open conically here, so that an additional speed reduction after the inflow of the exhaust gas A can be ensured for this.

The 8th shows one possibility of a fuel cell system 100 according to the invention. This is equipped with a fuel cell stack 110 here. This fuel cell stack 110 has an anode section 120 and a cathode section 130 . Anode feed gas AZG is fed to the anode section 120 via the anode feed section 122 . Similarly, cathode supply gas KZG is supplied to the cathode section 130 via the cathode supply section 132 . Anode off-gas AAG is discharged via the anode discharge portion 124 and cathode off-gas KAG is discharged via the cathode discharge portion 134 . In the embodiment of 8th a separating device 10 according to the present invention is now shown in the anode discharge section 124 and can ensure that water is separated and the anode off-gas AAG is dried as off-gas A. Of course, a separating device 10 can also be arranged in the cathode removal section 134 in the same or a similar manner. The dried anode off-gas AAG can now be fed to the anode feed section 122 as recirculation gas or else be discharged to the environment as a common off-gas with cathode off-gas.

The above explanation describes the present invention solely within the framework of examples.

Reference List

10

separating device

20

body

22

gas inlet

23

gas inlet wall

24

gas outlet

30

separation section

31

sidewall

32

guide wall

33

Initial Bend Section

34

End Bend Section

36

lead recording

37

backstop

40

catch section

42

backstop element

100

fuel cell system

110

fuel cell stack

120

anode section

122

anode feeding section

124

anode discharge section

130

cathode section

132

cathode feeding section

134

cathode discharge section

W

Water

A

exhaust

AR

direction of gravity

GA

body axis

AZG

anode feed gas

AAG

anode exhaust

KZG

cathode feed gas

KAG

cathode exhaust

Claims (15)

Separation device (10) for separating liquid water (W) from an exhaust gas (A) in an exhaust gas section of a fuel cell system (100), having a base body (20) with a separating section (30) for separating liquid water (W) from the exhaust gas (A) 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 separating section (30) for the inlet of exhaust gas (A) and a gas outlet (24) downstream of the separating section (30) for the outlet of exhaust gas (A), characterized in that the separating section (30) has a curved guide wall (32) for receiving and guiding the exhaust gas (A) from the gas inlet (22) and the curvature thereof Guide wall (32) reduces from an initial curve section (33) away from the gas inlet (22) to a final curve section (34). Separating device (10) after claim 1 , characterized in that the initial curved section (33) of the guide wall (32) produces a deflection of the guided exhaust gas (A) in the range between at least 30° and a maximum of 360°. Separating device (10) according to one of the preceding claims, characterized in that the guide wall (32) extends away from the gas inlet (22) from the initial curved section (33) to the final curved section (34), in particular along a direction of gravity (SR) , extending downward. Separating device (10) according to one of the preceding claims, characterized in that the flow cross section of the separating section (30) increases from the initial curved section (33) to the final curved section (34). Separating device (10) according to one of the preceding claims, characterized in that the separating section (30) is designed without a siphon section. Separating device (10) according to one of the preceding claims, characterized in that the separating section (30) is designed as an inverted cyclone separator. Separating device (10) according to one of the preceding claims, characterized in that the curvature of the guide wall (32) decreases from the initial curved section (33) to the final curved section (34) without kinks, in particular continuously or essentially continuously. Separating device (10) according to one of the preceding claims, characterized in that the guide wall (32), in particular at least in the curved end section (34), has at least one guide receptacle (36) for receiving and discharging water (W). Separating device (10) after claim 8 , characterized in that the at least one guide receptacle (36) is aligned at least in sections along or essentially along a direction of gravity (SR). Separating device (10) according to one of Claims 8 or 9 , characterized in that the at least one guide receptacle (36) has a backstop (37), in particular in the form of at least one backstop lip, for preventing the water (W) that has been taken up from running back. Separating device (10) according to one of the preceding claims, characterized in that the collecting section (40) has a non-return element (42) for preventing collected water (W) from flowing back into the separating section (30). Separating device (10) according to one of the preceding claims, characterized in that the base body (20) has at least two gas inlets (22) for the inlet of exhaust gas (A) into the separating section (30), the two gas inlets (22) being related to one Body axis (GA) of the body (20) are arranged at different heights. Separating device (10) according to one of the preceding claims, characterized in that the base body (20) is produced by a build-up process. Separating device (10) according to one of the preceding claims, characterized in that the gas inlet (22) extends from a side wall (31) of the separating section (30) into the separating section (30). Fuel cell system (100), having at least one fuel cell stack (110) with an anode section (120) and a cathode section (130), the anode section (120) having an anode feed section (122) for supplying anode feed gas (AZG) and an anode discharge section (124) for Discharging anode waste gas (AAG), the cathode section (130) having a cathode feed section (132) for supplying cathode feed gas (KZG) and a cathode discharge section (134) for discharging cathode waste gas (KAG), further having a separating device (10) with the features of a the Claims 1 until 14 whose gas inlet (22) is connected in fluid communication with the anode discharge section (124) or the cathode discharge section (134).

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