DE102015015715A1 - Separating element and fuel cell system - Google Patents

Abstract

The invention relates to a separating element (10) for removing a fluid from a media flow, in particular air flow, comprising a tubular flow element (11) having a flow inlet (12), a flow outlet (14) and a collecting region (16) for the flow from the medium removed fluid. The collecting area (16) is arranged in a region between the flow inlet (12) and the flow outlet (14). A deflection of the flow direction (18) of the media flow from the flow inlet (12) to the flow outlet (14) is provided in the region of the collection region (16) for inertial separation of the fluid. The collecting area (16) forms a protuberance (66) of the tubular flow element (11), which increases in depth in the flow direction (18). The invention further relates to a fuel cell system (100) having a fuel cell stack (102) with at least one fuel cell (104), comprising a gas supply unit (60) with an anode gas supply (62) and a cathode gas supply (64), and at least one separation element (10).

Description

Technical area

The invention relates to a separation element for removing a fluid from a media flow, in particular an air flow, and a fuel cell system having a separation element.

State of the art

Liquid separators, in particular liquid separators for fuel cell systems, are known from the general state of the art. In particular, they are there to separate liquid from a two-phase mixture of typically exhaust gas or exhaust air and water, in particular in the form of droplets. They thus protect downstream components from the liquid droplets, for example a high-speed turbine in the region of the anode outlet of a fuel cell.

The DE 10 2012 023 682 A1 describes a liquid separator, which is provided in that it has in a flow inlet in front of the droplet arranged flow inlet at least one flow guide for uniformly distributing the two-phase flow on the cross-sectional area of the Droplet. About such a flow guide a division of the two-phase flow is achieved over the entire inflowable cross-section of the droplet. The division can be carried out so that in almost all operating situations of the fuel cell system, the two-phase mixture impinges on the surface of the droplet with a uniformly distributed over the entire surface flow velocity, so that the droplets deposited and can not be entrained by the material of the Droplet through.

From the JP 2007 188641 For example, a fuel cell system is known in which piping is used to deliver gas up to a gas inlet of the fuel cell stack. In this case, an inertia separator is formed over a part of the pipeline by bending the pipeline in order to separate dirt particles in the gas stream as well as dirt particles mixed with liquid droplets from the gas stream and to collect in the lower part of the pipeline.

Disclosure of the invention

An object of the invention is to provide a simple and reliable separation element which allows a fluid, in particular oil drops, to be removed from a medium flow, in particular from an air flow.

Another object of the invention is to provide a fuel cell system with a gas supply with a separation element, which is to operate as reliable and easy to maintain.

The above objects are achieved according to one aspect of the invention by a separation element for removing a fluid from a media flow, in particular an air flow, in which a deflection of the flow direction of the media flow is provided from a flow inlet to a flow outlet in the region of a collection region for inertial separation of the fluid. In this case, the collecting area forms a protuberance of the tubular flow element, which increases in depth in the flow direction.

According to a further aspect of the invention, the object is achieved by a fuel cell system having a fuel cell stack with at least one fuel cell, comprising a gas supply unit with an anode gas supply and a cathode gas supply, and at least one separation element.

Favorable embodiments and advantages of the invention will become apparent from the other claims, the description and the drawings.

The invention relates to a separating element for removing a fluid from a media flow, in particular air flow, which comprises a tubular flow element having a flow inlet, a flow outlet and a collecting region for the fluid removed from the media flow. In this case, the collecting region is arranged in a bottom region between the flow inlet and the flow outlet. There is provided a deflection of the flow direction of the media flow from the flow inlet to the flow outlet in the region of the collecting region for inertial separation of the fluid. The collecting area forms a protuberance of the tubular flow element, which increases in depth in the flow direction.

The separating element according to the invention, which can be used in particular for separating oil droplets from an air stream of a cathode gas supply of a fuel cell system, is well suited for the separation of larger droplet diameters and thereby generates only a small differential pressure. Oil drops can come, for example, from upstream compressors, which do not have to be lubricated with oil, but can still release small traces of oil, which then entrained in the air flow become. The separation element described has over the prior art for oil mist separation, which include the use of Rohrbogenabscheidern, swirl generators, wire knits, cyclones, etc., decisive advantages. In the prior art, for example, separators are described with an oil reservoir in which the separated oil can be collected. This oil reservoir is usually provided with a drain mechanism, such as a screw, through which drain mechanism, the separated oil can be discharged. In the separation element according to the invention, however, the oil can be bound and collected via an oil-binding material in a collecting area.

Advantageously, the chord of the pipe bend between flow inlet and flow outlet lie in a plane. Conceivable, however, are also more complex geometries.

As a result, the separating element according to the invention further avoids the risk that already separated oil (for example an oil film) will be torn off again so that a secondary droplet mist can form downstream of the separating element.

The separation element according to the invention comprises a pipe elbow, which is well suited for the separation of large drops and provides an advantageous differential pressure. During a deflection of the media flow, fluid drops in the media flow are deposited on the wall of the flow element in the region of the deflection due to the inertia of the mass. Furthermore, in a collecting region of the separating element, which is preferably arranged in the region of the deflection of the media flow to the lowest point of the separating element, a fluid-binding material is provided, which separates the separated fluid, for. B. Ölk, can permanently bind and so the emergence of a secondary oil mist by re-entrainment, so the entrainment of already separated oil drops in the media flow, reduced. For this purpose, fiber materials can be used, such as polypropylene (PP) meltblowns or natural fibers such as cotton or kapok fibers. Furthermore, the use of oil-binding powders / granules is conceivable.

Advantages of the described separation element are thus the separation of oil through the simple and reliable inertial separation as well as reducing or even preventing the re-entrainment of already separated oil. Used today, z. B. air bearing oil-free compressors are very expensive due to the requirement for the purity of the exiting air. In combination with this separation element, the overall system costs can be reduced, for example, by the fact that simpler, easily oil-emitting and therefore cheaper compressors can be used.

The separation element can consist of a tubular element which is inexpensive to produce, as is used in conventional tube sheet separators and can be produced by a conventional injection molding process. In the simplest embodiment, the separation element may comprise a bent through 90 ° elbow. In the region of the tube curvature, the collecting region for the separated oil can then be arranged in the form of a protuberance or bulge on the curvature outside. The cross-section of the separation element may be circular, as is usual with a pipe bend separator. Alternatively, however, other cross-sections such as oval or rectangular cross-sections can be used advantageously.

According to an advantageous embodiment, a coalescing medium for coalescing droplets of the fluid can be arranged in the flow inlet. In the event that in the oil droplets mist smaller drops are present, which could not deposit the pipe elbow, the coalescence stage, z. As a knitted wire as a coalescing medium, upstream. This coalescing stage coalesces the small liquid droplets and then creates the droplet spectrum for which the pipe elbow is designed, with only a slight increase in differential pressure. The wire knit can be attached either perpendicular to the air flow or obliquely at an angle thereto.

According to an advantageous embodiment, the direction of flow of the media flow may be directed in normal use from the vertical in the horizontal. Thus, the media flow, so for example air from an upstream compressor, be directed vertically from above into the tubular flow element of the separation element down and be deflected by the separation element in the horizontal. In this case, due to the curvature of the tubular flow element, the fluid, for example oil droplets, can be deposited on the wall of the separating element into the collecting area and, guided by gravity, run downwards and collect in the collecting area.

According to an advantageous embodiment, the collecting region at the downstream end can end in an end region which, when used as intended, is lower than a lower edge of the flow outlet of the tubular flow element. As a result, the separated oil can accumulate in the deeper end area and the risk that separated oil drops from the air flow in the direction of the Flow outlet of the separation element be entrained, can be reduced. Also, the remaining flow area for the air flow is narrowed as little as possible.

According to an advantageous embodiment, a shoulder can be formed at the transition of the end region to the tubular flow element. By the step, which may be formed as a step in the region in which the end portion of the collecting area again merges into the circular cross-section of the tubular flow element, the separated oil drops can be prevented in the course of re-entrainment of the air flow back into the Flow outlet be entrained and so may affect a fuel cell stack. The heel may be provided more or less sharp-edged and more or less high depending on the intended flow velocity.

According to an advantageous embodiment, the bottom of the collecting area may be formed flat in the tangential direction. The bottom of the collecting area may be provided tangentially or parallel to a tangent of the outside of the flow element. A flat bottom in the tangential direction favors a larger footprint of the collection area in which the deposited oil drops can be collected compared to a circumferentially curved bottom of a pipe section. The separated oil can spread so cheap and overall can be more absorbed before the collection area is exhausted. Also, the risk is reduced that in case of slight imbalance of the separation element oil can still get into the flow outlet.

According to an advantageous embodiment, a flow cross section of the flow inlet may be smaller than a flow cross section of the flow outlet. A smaller flow cross-section in the flow inlet, which decreases progressively to the flow outlet, favors a slight increase in the flow velocity and thus a more favorable separation behavior for the oil droplets to be separated. This can increase the efficiency of the separation element and reduce the risk of re-entrainment.

According to an advantageous embodiment, the deflection of the media flow by an angle of at least 45 °, preferably at least 60 °, most preferably at least 90 °. The tubular flow element of the separation element can be designed and optimized in a favorable manner, depending on the media flow used and the fluid to be deposited. Depending on the media flow and fluid as well as the flow velocity, different deflection angles of the media flow may prove favorable and the design of the separation element may be adapted to the boundary conditions.

According to an advantageous embodiment, a fluid-binding material can be arranged in the collecting area. Advantageously, the separated fluid can be bound by a suitable fluid-binding material, so that the risk that the separated fluid is entrained again by the media flow, can be reduced. For this purpose, fiber materials can be used, such as polypropylene (PP) meltblowns or natural fibers such as cotton or kapok fibers. The fluid binding materials may be provided in the form of a mat or mat. Furthermore, the use of oil-binding powders / granules as a bed or in bound form on a substrate is conceivable.

According to an advantageous embodiment, an apparent element can be provided in order to remove the fluid-binding material from the collecting area or to introduce it into the collecting area. Conveniently, an opening or flap may be provided on the separator to exchange the fluid-binding material should its capacity for absorption by the separated fluid be exhausted. For this purpose, the disclosed element can release an opening into the collecting area, so that the fluid-binding material can be removed and a fresh fluid-binding material can be introduced. Thereafter, the openable element is closed again to ensure an unimpeded flow of the media flow.

According to an advantageous embodiment, at least a part of the collecting region may be formed with the fluid-binding material as an exchangeable element of the tubular flow element. It is also possible to form the fluid-binding material in the form of an exchange element as part of the tubular flow element, so that when replacing the fluid-binding material, the entire exchange element can be removed from the separation element and replaced by a new exchange element with fresh fluid-binding material. Thus, the fluid binding material can be exchanged like a replaceable filter element.

According to an advantageous embodiment, the fluid-binding material may be materially secured, for example by welding, and / or positively, in particular undercut, in the collecting area. The fluid binding material may be welded as well as glued or riveted or attached in an otherwise meaningful manner. In particular, the fluid-binding material as a mat According to an advantageous embodiment, the collecting area may have an outlet for separated fluid. Instead of a fluid binding material or in combination with a fluid binding material, it is possible to provide an outlet for separated fluid at the collection area. In this way, accumulated and / or unbound fluid can be drained from the collection area via a drain plug, for example. The outlet is placed at the lowest point of the collection area, which occurs in the end region, to drain the accumulated fluid by gravity and to flow out.

According to an advantageous embodiment, the coalescence medium can be arranged transversely to the flow direction. The coalescing medium serves to coalesce small drops of fluid into larger drops of fluid, which can then be separated from the media flow due to inertial separation. For this purpose, it is expedient if the entire media flow flows through the coalescing medium. For this reason, it is favorable if the coalescence medium is arranged transversely to the flow direction of the media flow and thus across the flow inlet. Conveniently, a consistency of the coalescing medium is chosen such that the differential pressure when flowing through the coalescing medium is not too great.

According to an advantageous embodiment, the coalescing medium can be arranged at an angle oblique to the flow direction. Alternatively, it is also possible to arrange the coalescing medium in the flow inlet so that the coalescing medium is oriented obliquely to the flow direction. In this case, part of the flow cross-section of the flow inlet may be free, so that only part of the medium flow flows through the coalescing medium. However, the coalescing medium can also be arranged obliquely to the flow direction, that nevertheless the entire media flow must flow through the coalescing medium. In this way it is conveniently possible to increase the effective thickness of the coalescing medium and thereby increase the efficiency of coalescence.

According to an advantageous embodiment, the flow direction can be provided in the direction of gravity when used as intended in the flow inlet. It is beneficial if the media flow is oriented in the direction of gravity, as this increases the effect of gravity in the deposition of the fluid by the flow rate of the media flow. This increases the efficiency of the separation element and lowers the risk of re-entrainment. The separated fluid drops hit the wall of the collecting area or the fluid-binding material at a higher speed and thus adhere better.

According to an advantageous embodiment, holding elements for fixing the fluid-binding material can be provided in the collecting area. The fluid-binding material is expediently provided as a fleece or mat. In order to keep the fluid-binding material in the intended place, holding elements, for example in the form of bars, may be provided in the collecting area, under which the nonwoven or the mat can be pushed and which then hold the fluid-binding material. Thus, the fluid-binding material can be held in place even at higher flow velocities and fulfill its function safely and reliably. Even with movements of the separating element, the fluid-binding material is securely held.

According to an advantageous embodiment, downstream of the coalescing medium, a grille for supporting the coalescence medium can be provided. The grid may, for example, hold the coalescing medium at its intended place in the flow inlet of the separation element. The grid supports the coalescing medium against the flow pressure of the media flow. The mesh size of the grid can be suitably selected to ensure the lowest possible pressure loss through the attachment of the grid in the flow cross-section of the tubular flow element. Alternatively and / or additionally, the coalescing medium can also be attached to an inner wall of the pipe elbow by gluing, welding or related joining methods.

According to a further aspect, the invention relates to a fuel cell system with a fuel cell stack having at least one fuel cell, comprising a gas supply unit with an anode gas supply and a cathode gas supply and at least one separation element as described above.

According to an advantageous embodiment, the at least one separation element for separating oil in the cathode gas supply between the gas supply unit and the fuel cell stack, in particular downstream of a compressor, may be provided.

Brief description of the drawings

Further advantages emerge from the following description of the drawing. In the drawings, embodiments of the invention are shown. The drawings, the description and the claims contain numerous features in combination. The person skilled in the art will expediently also consider the features individually and combine them into meaningful further combinations. They show by way of example:

1 a separator for removing a fluid from a fluid flow in the form of a pipe bend according to an embodiment of the invention in side view;

2 the separation element after 1 in a sectional plan view;

3 the separation element after 1 in a side view;

4 the separation element after 1 in a longitudinal section; and

5 a fuel cell system with gas supply unit and separation element for removing oil droplets from the cathode gas supply according to an embodiment of the invention in a schematic representation.

Embodiments of the invention

In the figures, the same or similar components are numbered with the same reference numerals. The figures are merely examples and are not intended to be limiting.

1 shows a separation element 10 for removing a fluid from a media flow, in particular an air flow, in the form of a pipe bend according to an embodiment of the invention in side view. The separation element 10 comprises a tubular flow element 11 with a flow inlet 12 through which the media flow into the separation element 10 flows in and a flow outlet 14 through which the media flow the separation element 10 leaves again. Next, the tubular flow element 11 a collection area 16 for the fluid removed from the media flow which is in an area between the flow inlet 12 and the flow outlet 14 is arranged. The collection area 16 forms a tangentially arranged protuberance 66 or bulge of the tubular flow element 11 in the region of the curvature outside, in the flow direction 18 increases in flow cross-section, with a bottom 68 of the collection area 16 on the tangential outside of the tubular flow element 11 is arranged. The collection area 16 runs at the downstream end into an end region 70 off, which is lower than the flow outlet when used as intended 14 the tubular flow element 11 , A paragraph 72 is at the transition of the end region 70 to the tubular flow element 11 trained, however, in 1 not to be recognized, as the paragraph 72 in the tubular flow element 11 is arranged. The floor 68 of the collection area 16 is in the tangential direction of the tubular flow element 11 flat. The flow cross-section of the flow inlet 12 is slightly larger than the flow area of the flow outlet 14 , so that the flow rate when flowing through the separation element 10 increases and so the deposition behavior of the fluid is favorably influenced.

In the separation element 10 finds a deflection of the flow direction 18 the media flow from the flow inlet 12 to the flow outlet 14 in the area of the collection area 16 which causes an inertial separation of the fluid. The flow direction 18 runs in a plane so that the tubular flow element can be designed as a pipe bend. The media flow flows in the vertical direction from above into the separation element 10 , is deflected into the horizontal and leaves the separation element 10 through the flow outlet 14 in the horizontal. The deflection of the media flow takes place by an angle 30 of at least 45 °, preferably at least 60 °, very particularly preferably at least 90 °. In the illustrated embodiment, there is a deflection of the media flow by an angle 30 of 90 °. The flow direction 18 is in intended use in the flow inlet 12 provided in the direction of gravity, which also designed the deposition behavior of the fluid due to gravity low. The fluid drops to be deposited thus become not only by the flow rate of the media flow but also by gravity to the outside of the curved tubular flow element 11 where also the collection area 16 is arranged for the separated fluid, steered. So the fluid drops hit the wall of the collection area 16 or the - not shown in this figure - fluid-binding material 22 and can be so conveniently deposited and collected.

The collection area 16 can optionally have an outlet 24 for deposited fluid, as in the embodiment in 1 is shown schematically. This may be, for example, a drain valve or a drain plug.

2 shows the separation element 10 to 1 in a sectional plan view corresponding to in 1 represented line AA. The constriction of the wall of the tubular flow element 11 , what a 2 can be seen on the cutting edge, stems from the rounding of the pipe bend of the tubular flow element 11 ago. Inside the separation element 10 is in the collection area 16 the fluid binding material 22 shown in the ground 68 of the collection area 16 is arranged. Above the fluid binding material 22 are holding elements 26 arranged, which the fluid binding material 22 in the ground 68 fix. The holding elements 26 are shown in the form of unilaterally fixed rods, so that the fluid-binding material, such as a fleece or a mat, can be pushed and fixed underneath.

In 3 is the separation element 10 to 1 in a opposite side view 1 rotated by 90 ° side view. The flow outlet 14 lies in the plane of the drawing, so that the fluid-binding material 22 , which by the holding elements 16 is fixed, can be seen. Also, the protuberance is 66 the tubular flow element 11 which the collection area 16 forms recognizable in the projection shown. The collection area 16 is thus shown in the projection over the flow cross-section largely rectangular, so that in a tangential direction flat bottom 68 results. The lowest point of the collection area 16 is lower than the flow outlet 14 so that separated fluid is in the collection area 16 can collect and not in the direction of the flow outlet 14 flows. Paragraph 72 at the transition from the end area 70 to the tubular flow element 11 supports this retention of the separated fluid in the collection area 16 in the form of a step, so that the separated fluid from the media flow also not back towards the flow outlet 14 being carried away.

At the separation element 10 in 3 is the outlet 24 for deposited fluid omitted in the illustration.

4 shows the separation element 10 to 1 in a longitudinal section along the in 3 shown line BB. The collection area 16 is as a protuberance 66 or bulge of the tubular flow element 11 trained and with the ground 68 on the tangential outside of the tubular flow element 11 arranged. Inside the tubular flow element 11 is the ground 68 with the fluid binding material 22 in the form of a non-woven or a mat, wherein the fluid-binding material 22 additionally by the retaining elements 26 in the form of bars on the inside of the floor 68 is fixed. The low-lying end area 70 of the collection area 16 has the outlet shown schematically 24 for separated fluid. The end area 70 goes with a paragraph 72 back into the contour of the tubular flow element 11 over which into the flow outlet 14 empties.

Conveniently, in the area of the collection area 16 the tubular flow element 11 an openable element may be provided to the fluid binding material 22 after exhausting its binding capacity from the collection area 16 to remove or new fluid-binding material 22 in the collection area 16 introduce. Alternatively, at least a part of the collection area 16 with the fluid binding material 22 as an exchangeable element of the tubular flow element 11 be formed so that pulled out in the form of a drawer solution, the replaceable element, and a new can be used again. In this case, the drawer element can also be reused as a receptacle and only the fluid-binding material contained therein can be exchanged.

In the flow inlet 12 of the separation element 10 is a coalescence medium 20 arranged, which coalesces smaller fluid drops to larger fluid droplets. The coalescing medium 20 is at the in 4 illustrated embodiment transverse to the flow direction 18 arranged. Alternatively, the coalescing medium 20 also at an angle oblique to the flow direction 18 be arranged and over the entire flow cross-section of the tubular flow element 11 be executed or alternatively only cover part of the flow cross-section. Downstream of the coalescing medium 20 is a grid 28 for supporting the coalescing medium 20 provided, which is the weight of the coalescer 20 contributes and supports against the flow pressure of the media flow.

5 shows a fuel cell system 100 with gas supply unit 60 and separation element 10 for removing oil droplets from the cathode gas supply 64 according to an embodiment of the invention in a schematic representation. The fuel cell system 100 includes a fuel cell stack 102 with a series of fuel cells 104 , which via an anode gas supply 62 and a cathode gas supply 64 from the gas supply unit 60 be supplied. In the direction of the cathode gas supply is the separation element 10 arranged, which for the separation of oil contaminants in the compressed air of the gas supply unit 60 for example, by an upstream compressor is used. The compressor is at the in 5 illustrated fuel cell system 100 within the gas supply unit 60 arranged.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been 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.

Cited patent literature

• DE 102012023682 A1 [0003]
• JP 2007188641 [0004]

Claims (19)

Separation element ( 10 ) for removing a fluid from a media flow, in particular air flow, comprising a tubular flow element ( 11 ) with a flow inlet ( 12 ), a flow outlet ( 14 ), as well as a collection area ( 16 ) for the fluid removed from the media flow, which collection area ( 16 ) in a bottom area between the flow inlet ( 12 ) and the flow outlet ( 14 ), wherein a deflection of the flow direction ( 18 ) of the media flow from the flow inlet ( 12 ) to the flow outlet ( 14 ) between the beginning and the end of the collection area ( 16 ) is provided for inertial separation of the fluid, wherein the collecting area ( 16 ) a protuberance ( 66 ) of the tubular flow element ( 11 ), which in the flow direction ( 18 ) increases in depth. Separating element according to claim 1, wherein in the inflow region ( 12 ) a coalescing medium ( 20 ) is arranged for coalescing droplets of the fluid. Separating element according to claim 1 or 2, wherein the flow direction ( 18 ) of the media flow is directed in normal use from the vertical in the horizontal. Separating element according to one of the preceding claims, wherein the collecting area ( 16 ) at its downstream end into an end region ( 70 ), which, when used as intended, is lower than a lower edge of the flow outlet ( 14 ) of the tubular flow element ( 11 ). Separator element according to claim 4, wherein a shoulder ( 72 ) at the transition of the end region ( 70 ) to the tubular flow element ( 11 ) is trained. Separator element according to one of the preceding claims, wherein the bottom ( 68 ) is formed flat in the tangential direction. Separating element according to one of the preceding claims, wherein a flow cross-section of the flow inlet ( 12 ) is smaller than a flow cross-section of the flow outlet ( 14 ). Separator element according to one of the preceding claims, wherein the deflection of the media flow by an angle ( 30 ) of at least 45 °, preferably at least 60 °, most preferably at least 90 °. Separating element according to one of the preceding claims, wherein in the collecting area ( 16 ) a fluid binding material ( 22 ) is arranged. A separation element according to claim 9, wherein an openable element is provided to seal the fluid binding material ( 22 ) from the collection area ( 16 ) or to the collection area ( 16 ) introduce. Separating element according to claim 9 or 10, wherein at least a part of the collecting area ( 16 ) with the fluid binding material ( 22 ) as an exchangeable element of the tubular flow element ( 11 ) is trained. Separator element according to one of claims 9 to 11, wherein the fluid-binding material ( 22 ) cohesively and / or positively, in particular undercut, in the collecting area ( 16 ) is attached. Separating element according to one of the preceding claims, wherein the collecting area ( 16 ) an outlet ( 24 ) for deposited fluid. Separating element according to one of claims 1 to 13, wherein the coalescing medium ( 20 ) at an angle oblique to the flow direction ( 18 ) is arranged. Separating element according to one of the preceding claims, wherein the flow direction ( 18 ) when used as intended in the flow inlet ( 12 ) is provided in the direction of gravity. Separating element according to one of the preceding claims, wherein in the collecting area ( 16 ) Holding elements ( 26 ) for fixing the fluid-binding material ( 22 ) are provided. Separator element according to one of the preceding claims, wherein downstream of the coalescence medium ( 20 ) a grid ( 28 ) for supporting the coalescing medium ( 20 ) is provided. Fuel cell system ( 100 ) with a fuel cell stack ( 102 ) with at least one fuel cell ( 104 ), comprising a gas supply unit ( 60 ) with an anode gas supply ( 62 ) and a cathode gas supply ( 64 ), as well as at least one separation element ( 10 ) according to any one of the preceding claims. Fuel cell system according to claim 18, wherein the at least one separating element ( 10 ) for the separation of oil in the cathode gas supply ( 64 ) between the gas supply unit ( 60 ) and the fuel cell stack ( 102 ), in particular downstream of a compressor, is provided.

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