EP3723888A1

EP3723888A1 - Phase separator for a fuel cell

Info

Publication number: EP3723888A1
Application number: EP18833690.3A
Authority: EP
Inventors: Jean-Philippe Poirot-Crouvezier; Philippe Manicardi
Original assignee: Commissariat a lEnergie Atomique CEA; Commissariat a lEnergie Atomique et aux Energies Alternatives CEA
Current assignee: Commissariat a lEnergie Atomique et aux Energies Alternatives CEA
Priority date: 2017-12-15
Filing date: 2018-12-12
Publication date: 2020-10-21
Also published as: FR3075066B1; WO2019115941A1; FR3075066A1

Abstract

The invention concerns a phase separator (1), comprising: - first and second parallel conduits (21, 22), connected by a first hairpin junction (41) configured to reverse the direction of fluid flow between the first and second conduits (21, 22), the first junction (41) comprising, starting from the first conduit towards the second conduit, first and second sections (411, 412) contiguous with one another, the first section having an average flow cross-section less than that of the first conduit, the second section having an average flow cross-section greater than that of the first section; - a back wall (10) extending between the first and second conduits (21, 22) passing through the first junction (41); and - an opening for discharge of liquid (13).

Description

PHASE SEPARATOR FOR FUEL CELL

The invention relates to fuel cells, and in particular to phase separators for reactant recovery circuits for fuel cells.

In a proton exchange membrane fuel cell, the reagents must be conducted to the reactive zone, the products, non-reactive species and the heat produced must be removed from the reactive zone.

By using air as the oxidizer, this air is led to the reactive zone after having generally passed through a series of components, such as a filter, a heat exchanger, or a humidifier). At the cathodic outlet, the residual air is generally dewatered to recover water, and then generally discharged through a discharger, to maintain a pressure in the cathodic reactive zone.

At the anode level, fuel such as dihydrogen is brought under pressure to the reactive zone. If the fuel supplied by a feed is sufficiently pure (eg more than 99.5% of the main chemical component of the off-water fuel), the stream recovered at the anode outlet can be mixed with the feed supplied by the feed, prior to introduce the mixture at the anode inlet.

The proton exchange membrane passes a small amount of nitrogen and water produced at the cathode to the anode. Recirculation is both tolerant of nitrogen pollution at the outlet of the anode, and also allows to benefit from moisture at the outlet of the anode, to moisten the fuel at the entrance of the anode . If it is desired to maintain moisture in the hydrogen, however, it is desired to avoid the formation of drops of water, which may block pipes in the reactive zone. Therefore, it is advantageous to avoid cooling the anode outlet, otherwise the moisture will condense in the form of droplets.

To avoid reintroducing droplets at the anode inlet by recirculation from the anode outlet, it is common to introduce a phase separator at the anode outlet. It is also known to introduce a phase separator at a non-pure oxidizer feed mixed with the cathode outlet. It is important to guarantee an important anodic flow, in order to avoid a concentration of nitrogen coming from the formation. The permeation of nitrogen causes its progressive accumulation in the fuel recirculation circuit. Although the nitrogen is inert, its too high concentration can lead to the stopping of the fuel cell. To avoid such a stop, a periodic or continuous purge is performed. In order to avoid introducing droplets into the reactive zone, during condensation due to the mixing of a hot and humid reagent outlet with a cold reagent inlet, it is also known to dispose a phase separator between the zone of formation of the mixture and the entry of the reagent into the reactive zone.

To achieve phase separation in a fuel cell, it is known to perform either a gravity separation, a separation by centrifugal force, or a separation by inertia.

Gravity separation, as described in JP2007087718, includes an increase in the flow section, which slows the flow of fluid, and promotes droplet drop. However, such a separation device is then particularly bulky.

Centrifugal force separation as described in US 8034142) is also particularly bulky.

Inertial separation is described in US20120276461. Such phase separation induces a large pressure drop in the flow.

No known phase separator makes it possible both to achieve effective phase separation and in a sufficiently reduced volume.

The invention aims to solve one or more of these disadvantages. The invention thus relates to a phase separator as defined in the appended claims.

It will be understood by those skilled in the art that each of the features of the variants of the dependent claims or of the description may be independently combined with the features of an independent claim, without necessarily constituting an intermediate generalization.

The invention also relates to a power generation system as defined in the appended claims.

Other characteristics and advantages of the invention will emerge clearly from the description which is given hereinafter, by way of indication and in no way limitative, with reference to the appended drawings, in which:

FIG 1 is a schematic top view of the interior of a fuel cell phase separator according to a first embodiment of the invention;

FIG. 2 is a perspective view by transparency of the phase separator of FIG. 1;

FIG. 3 is an enlarged representation of part of the phase separator of FIG. 1; FIG. 4 is a schematic view from above of a phase separator for a fuel cell according to a variant of a second embodiment of the invention;

FIG. 5 is a schematic view from above of a phase separator for a fuel cell according to another variant of a second embodiment of the invention;

FIG. 6 is a schematic view from above of a phase separator for a fuel cell according to a variant of a third embodiment of the invention;

FIG. 7 is a schematic view from above of a phase separator for a fuel cell according to another variant of the third embodiment of the invention;

FIG 8 is a perspective view in section of a fuel cell phase separator according to another variant of the first embodiment of the invention;

FIG. 9 is a schematic view from above of a phase separator for a fuel cell according to another variant of the second embodiment of the invention;

FIG. 10 is a perspective view by transparency of a phase separator for a fuel cell according to another variant of the first embodiment of the invention;

FIG. 11 is a view from above of the inside of the phase separator of FIG. 10;

FIGS. 12 to 15 are diagrammatic representations of different system configurations each including a fuel cell and a phase separator according to the invention.

The invention proposes a phase separator provided with parallel pipes connected by a pin-shaped junction configured to reverse the direction of fluid flow between its pipes. In the direction of flow between these pipes, the junction comprises successive sections in the continuity of one another. A first section has a lower average flow section than one of the pipes, a second section having a mean flow section greater than that of the first section.

Figure 1 is a schematic top view of the interior of a phase separator 1 for fuel cell according to a first embodiment of the invention. FIG. 2 is a perspective view by transparency of the phase separator of FIG. 1. The phase separator 1 is in the form of a housing having an input 1 1 intended to receive a flow of reagent derived at least in part from a reagent exhaust from a fuel cell, an outlet 12 for supplying a gas stream to a reagent inlet of the fuel cell, and an exhaust outlet 13 of liquid. The evacuation outlet 13 is here positioned near the outlet 12.

The housing is here delimited by a bottom wall 10, a cover 15, side walls 14 and end walls (not referenced). The case here has a shape of a rectangular parallelepiped. The inlet 1 1 and the outlet 12 are formed as orifices in respective end walls. The outlet 13 is formed in the form of an orifice in the bottom wall 10. The inlet 1 1 and the outlet 12 are elevated here relative to the bottom wall 10. The flow entering the separator 1 at the level of the 1 1 inlet is intended to be separated between a gas stream discharged through the outlet 12, and a liquid flow discharged through the outlet 13. The housing is arranged so that the fluid flow is carried out generally parallel to the wall bottom 10 or in normal planes to the side walls 14.

Inside the housing formed by the phase separator 1, vertical walls 3 are formed between the bottom wall 10 and the lid 15. Parallel flow pipes 2 are formed between the successive vertical walls 3, perpendicular to the bottom wall 10. The walls 3 are here flat and parallel to each other. The phase separator 1 here comprises an alternation of walls 3 connected to a first wall 14 and providing a passage with a second wall 14, and walls 3 connected to the second wall 14 and providing a passage with the first wall 14. At the passages between the walls 3 and the walls 14, pin joints 4 are formed between the pipes 2 successive. The successive pipes 2 here have the same flow section.

FIG. 3 is an enlarged representation of a portion of the phase separator of FIG. The dashed line illustrates the geometric center of the flow channel formed through the phase separator 1. Dashed lines mark a boundary between flow channels and junctions. The dotted lines mark a delimitation between successive sections of a junction.

A pipe 21 is delimited between a wall 30 and a wall 31. A pipe 22 is parallel to the pipe 21, and delimited between the wall 31 and a wall 32. A pipe 23 is parallel to the pipe 22. The pipes 21 and 22 are connected by a hairpin junction 41. The pipes 22 and 23 are connected by a pin junction 42. The flow between the inlet 1 1 and the outlet 12 is thus carried out here in series between the pipes 21 to 23 in particular. The bottom wall 10 extends between the various pipes and joints, to the outlet 13.

The height in the housing being here constant at all points, the local passage section in the pipes and junctions here will be defined by the width of the passage at the geometric center of the flow channel.

The junction 41 comprises successive sections 410, 41 1, 412 and 413 and in continuity with each other. The sections 410 to 413 connect the pipes 21 and 22. The junction 42 comprises successive sections 420, 421, 422 and 423 and in continuity with each other. The sections 420 to 423 connect the pipes 22 and 23.

The section 41 1 has a lower average flow section than the pipe 21, thereby forming a narrowing. The section 41 1 thus makes it possible to accelerate the speed of the flow locally. The section 412 has a greater average flow section than the section 41 1, thus forming an enlargement. The section 412 thus makes it possible to locally slow down the flow velocity, favoring the drop of the droplets that have been accelerated in the section 41 1. In addition, the accelerated droplets in the section 41 1, tend to continue their course to the wall 14, due to the change of orientation along the hairpin junction 41. This configuration thus promotes a separation between the water and the gas in the flow. The droplets reaching the wall 14 or another wall tend to then run off to the bottom wall 10. Such a phase separation is furthermore obtained here with a minimum of obstacles to the flow, which makes it possible to limit the pressure drops in the separator 1.

The section 410 advantageously has an average flow section greater than that of the pipe 21, and greater than that of the section 41 1, which makes it possible to slow down the droplets present in the stream, before accelerating them in the section 41 1 with the change of orientation.

The section 413 advantageously has a lower average flow section than that of the section 412, in order to accelerate the flow.

Due to the presence of several parallel pipes connected by junctions, the flow of fluid through the phase separator 1 can not flow in a straight line from the inlet 1 1 to the outlet 12, and is obliged to to meander. Due to the inversion of the flow direction between the parallel pipes, the phase separator 1 makes it possible to accommodate a large length of fluid flow in a small space. The reversal of direction by the junctions between the pipes is furthermore used to form an alternation of narrowing and section widening, favoring a separation between the gas and the liquid of the flow through the separator 1. The junction 42 has the same geometry as the junction 41, and thus provides the same phase separation effects, forming more meanders to increase the compactness of the phase separator 1.

Advantageously, in order not to excessively increase the pressure drop in the phase separator 1, the flow section varies continuously in the junctions 41 and 42.

FIG. 4 is a schematic view from above of a phase separator 1 for a fuel cell according to a variant of a second embodiment of the invention. Such a phase separator 1 is intended to increase the efficiency of the phase separation in a given volume. In this example, the partition walls 31 and 32, delimiting the pipes 21, 22 and 23, extend in the junctions 41 and 42 respectively. The extensions of the walls 31 and 32 have protruding portions 415. Each of these projecting portions 415 is oriented in a direction opposite to the direction of the desired flow. Such a configuration makes it possible to retain the droplets and to avoid their re-entrainment by the flow of fluid.

By following the direction of the flow from the inlet 1 1 to the outlet 12, the junction 41 starts here with a narrowing at a projecting portion 415, then with a widening, then a narrowing at one end of the wall 31, then by an enlargement, then by a new narrowing connected to the pipe 22. The junction 42 has the same geometry as the junction 41.

In order to increase the compactness of the phase separator 1, it advantageously has an input 11 1 positioned near the outlet 121. In order to bring the inlet 1 1 1 close to the outlet 121, the flow lines of a phase separation part open onto a return duct 20 to the outlet 121.

In order to increase the phase separation efficiency for a given volume, the phase separator comprises another inlet 1 12 and another outlet 122, as well as another phase separation part, provided with a set of pipes. flow and junctions. The pipes and junctions of this other phase separation part have an arrangement symmetrical to that of the phase separation part described above. This other part of phase separation also opens on the return conduit 20, in order to pool it. The output 13 is here disposed near the outputs 121 and 122. The partition walls between the flow pipes are here non-planar.

Such a phase separator 1 is also particularly suitable for being shared for two different fuel cells. A first fuel cell may for example have a reagent exhaust connected to the input 1 1 1, a second fuel cell may have a reagent exhaust connected to the input 1 12.

Simulations were carried out with such a phase separator 1, with a moisture saturated hydrogen flow at 80 ° C and including droplets of 1 μm in diameter. With the simulations carried out, 90% of the droplets present in the stream were retained in the separator 1 with a pressure drop of 2.3 mbar.

FIG. 5 is a schematic view from above of a phase separator 1 according to another variant of the second embodiment of the invention. The phase separator 1 here has substantially the same configuration as that detailed with reference to FIG. 4. This phase separator 1 differs from that of FIG. 4 only in the presence in each junction of an outgrowth 416 arranged in a part external of this junction. Such protuberances 416 disposed in the orientation change formed by each junction, further promote phase separation. Such growths are advantageously formed in the junctions downstream of a narrowing in the direction of flow, in order to recover droplets that could have been accelerated in a narrowing.

Simulations were carried out with such a phase separator 1, with a moisture saturated hydrogen flow at 80 ° C and including droplets of 1 μm in diameter. With the simulations carried out, 96% of the droplets present in the stream were retained in the separator 1 with a pressure drop of 2.6 mbar.

Figure 6 is a schematic top view of a phase separator 1 according to a variant of a third embodiment of the invention. In this third embodiment, the partition walls between the flow conduits extend into the junctions. The partition walls are formed by the association of several vertical planar parts.

The partition walls here comprise a first portion 417 projecting in each junction, to form a narrowing at the entrance of this junction. Once this projection is crossed, the junction includes an enlargement. In the illustrated example, a protrusion 419 is formed in the junction at the walls 14, to form a narrowing. Such an outgrowth 419 promotes the recovery of droplets. The protuberances 419 are disposed in an outer portion of their respective junction.

The partition walls here comprise a second portion 418 projecting in each junction, to form a narrowing at the outlet of each junction. Figure 7 is a schematic top view of a phase separator 1 according to another variant of the third embodiment of the invention. In this variant, the partition walls between the flow pipes extend into the junctions. The partition walls are formed by the association of several planar parts.

The partition walls here comprise a first portion 417 projecting in each junction, to form a narrowing at the entrance of this junction.

In the illustrated example, a protrusion 419 is formed in the junction at the walls 14, to form a narrowing. Such an outgrowth 419 promotes the recovery of droplets. The protuberances 419 are disposed in an outer portion of their respective junction.

Figure 8 is a perspective view in section of a phase separator 1 according to another variant of the first embodiment of the invention.

The variant illustrated in FIG. 8 differs from that illustrated in FIG.

by the presence of a projecting portion 417 formed at the end of each partition wall, perpendicularly to this partition wall. Each projecting portion 417 forms a narrowing at the entrance of a junction;

by the presence of a projecting portion 418 formed at the end of each partition wall, perpendicularly to this partition wall. Each projecting portion 418 forms a narrowing at the exit of a junction;

by the presence of excrescences 300 on each partition wall, in the flow pipes;

by the presence of excrescences 416 in each junction, at the level of the walls 14, to form a narrowing. The protuberances 416 are disposed in an outer portion of each junction. Such protuberances 416 are disposed in the orientation change formed by each junction, promoting phase separation.

Figure 9 is a schematic top view of a phase separator according to another variant of the second embodiment of the invention. The phase separator 1 here has substantially the same configuration as those detailed with reference to FIG. 4. This phase separator 1 differs from that of FIG. 4 only in the presence of a purge orifice 16, at the connection level. between the phase separation parts and the return duct 20. The purge port 16 is intended to selectively discharge the contents of the phase separator 1. The outputs 121 and 122 are here intended to be connected to a recirculation circuit, for a reintroduction into the reactive zone of a fuel cell. FIG. 10 is a perspective view by transparency of a phase separator 1 according to another variant of the first embodiment of the invention. FIG. 11 is a view from above of the interior of the phase separator of FIG. 10. In this variant, a return duct 20 is arranged so as to allow the outlet 12 to be brought closer to the inlet 11. The inlet 11 is connected to a phase separation part, the phase separation part being connected by an output end to the return conduit 20. In the illustrated example, the output 13 is isolated from the input 11 via of a wall 17, to avoid a short circuit of the flow flow from the inlet 11 to the outlet 13. The outlet 13 is here formed under the wall 17.

Various configurations of a system 9 may be provided, including a fuel cell 5 and a phase separator 1 as described above.

Figure 12 is a schematic representation of a first configuration of a system 9 including a fuel cell 5 and a phase separator 1 according to the invention. The phase separator 1 has an input 11 connected to an anode exhaust collector of the fuel cell 5. The output 12 of the separator 1 is connected to an ejector 7, connected to a junction between a power supply 6 (for example a reservoir under pressure) in fuel (typically hydrogen) and an anode inlet manifold of the fuel cell 5. Thus, the fuel from the feed 6 can be humidified with gas from the exhaust manifold of the fuel cell. 5. The phase separator 1 is here attached as close as possible to the exhaust manifold of the fuel cell 5, in order to effect phase separation at a temperature close to the temperature of the reactive zone of the fuel cell 5. .

Fig. 13 is a representation of a second configuration of a system including a fuel cell 5 and a phase separator 1 according to the invention. The phase separator 1 has an output 12 connected to an anode input collector of the fuel cell 5.

The anode exhaust manifold of the fuel cell 5 is connected to an ejector 7. The ejector 7 is connected to a junction between a feed 6 (for example a pressurized tank) with fuel (typically dihydrogen) and the entering the phase separator 1. The phase separator 1 thus makes it possible to recover the water after mixing between the gases coming from the exhaust manifold of the fuel cell 5 and the fuel coming from the feed 6. In fact, the gases coming from the feed 6 can induce condensation of the moisture present in the gases coming from exhaust manifold. The phase separator 1 according to this configuration makes it possible to remove the condensed water after such mixing.

The examples of FIGS. 12 and 13 may also be applied by replacing the feed 6 with a supply of pure oxygen used as an oxidizer.

Figure 14 is a schematic representation of a third configuration of a system 9 including a fuel cell 5 and a phase separator 1 according to the invention. The phase separator 1 has an input 1 1 connected to a cathode exhaust manifold of the fuel cell 5. The output 12 of the separator 1 is connected to an input of a pump 8. The output of the pump 8 is connected at a T-junction 73. The T-junction 73 is also connected to an oxidizer inlet 71 (e.g., an air inlet).

It is thus possible to humidify the oxidant coming from the inlet 71 by means of the gas coming from the exhaust manifold of the fuel cell 5. The outlet of the T-junction is connected to a cathode inlet collector of the fuel cell 5, to introduce the oxidant mixture under pressure into the reactive zone. The phase separator 1 is here pressed closer to the exhaust manifold of the fuel cell 5, in order to achieve phase separation at a temperature close to the temperature of the reactive zone of the fuel cell 5.

Fig. 15 is a representation of a fourth configuration of a system including a fuel cell 5 and a phase separator 1 according to the invention.

The phase separator 1 has an input 1 1 connected to an output of a compressor 8. The output 12 of the phase separator 1 is connected to a cathode input collector of the fuel cell 5, in order to introduce the mixture oxidizer under pressure in the reactive zone.

An inlet of a pressure reducer 74 is connected to the cathode exhaust manifold of the fuel cell 5. An output of the expander 74 is connected to a T-junction 73. An oxidizer inlet 71 (for example an air inlet, or a tank of pure oxygen under pressure) is also connected to the T-junction 73. The T-junction 73 is moreover connected to the inlet of the compressor 8. It is thus possible to humidify the oxidant coming from the inlet 71 to gas from the exhaust manifold of the fuel cell 5.

The phase separator 1 thus makes it possible to recover the water after mixing between the gases coming from the exhaust manifold of the fuel cell. fuel 5 and the oxidant from the air inlet 71. Indeed, the gases coming from the air inlet 71 can induce condensation of the moisture present in the gases coming from the exhaust manifold. The phase separator 1 according to this configuration makes it possible to remove the condensed water after such mixing.

For recirculation on the air side:

The air can be brought from the air inlet 71 already pressurized to the pressure required by the battery;

The compressor 8 may be a booster compressor intended primarily to overcome the pressure drops of the circuit.

As the air consists essentially of nitrogen, a continuous outlet of exhaust gas is advantageously provided downstream of the fuel cell 5 or downstream of the phase separator 1.

It can be provided that the phase separator 1 is attached to the fuel cell, for example to an end plate of a battery or to a cylinder head connecting several batteries.

Advantageously, one of the walls of the phase separator 1 forms an exchanger with a coolant flow of a fuel cell. Such an exchanger makes it possible to maintain a temperature in the phase separator 1 greater than the ambient temperature. It is thus possible to promote the maintenance of water in the vapor phase in the flow.

In the foregoing examples, the bottom wall 10 is positioned parallel to the flow of fluid in the phase separator 1, for example parallel to a plane passing on the one hand by the inlet 1 1 and on the other hand It is advantageous to form a bottom wall 10 that is not parallel to the fluid flow plane. For example, the bottom wall 10 may be inclined so that the outlet 13 is positioned on a low point of this bottom wall 10. The inclination of the bottom wall 10 and the position of the outlet 13 may take account of the inclinations can take the phase separator 1 for embedded applications. The outlet 13 is here formed in the bottom wall 10 but can also be made in the lower part of vertical walls 14.

Claims

1. Phase separator (1), characterized in that it comprises:

first and second parallel pipes (21, 22), connected by a first pin-shaped junction (41) configured to reverse a direction of fluid flow between the first and second pipes (21, 22), the first junction (41); ) comprising, starting from the first pipe towards the second pipe, first and second sections (41 1, 412) in continuity with one another, the first section having a mean flow section smaller than that of the first pipe, the second section having a mean flow section greater than that of the first section;

a bottom wall (10) extending between the first and second pipes (21, 22) passing through the first junction (41);

a liquid discharge orifice (13).

2. phase separator (1) according to claim 1, wherein said first junction (41) comprises a third section (413) in the continuity of the second section (412), the third section (413) having an average section of flow less than that of the second section.

3. phase separator (1) according to claim 2, wherein said first junction (41) comprises a fourth section (410) disposed between the first pipe (21) and the first section (41 1) and disposed in the continuity of first section, the fourth section having a mean flow section greater than that of the first section and greater than that of the first pipe.

4. Phase separator (1) according to any one of the preceding claims:

further comprising a third duct (23) parallel to the second duct (22) and having the same average flow section as the first and second ducts, the second and third ducts (21, 22) being connected by a second junction pin (42) configured to reverse a direction of fluid flow between the second and third pipes (42,43), the second joint having the same geometry as the first joint;

-the bottom wall (10) extending between the second and third pipes (42,43) through the second junction.

Phase separator (1) according to any one of the preceding claims, wherein said first and second pipes (21, 22) and the first junction (41) are delimited by vertical walls (31) substantially perpendicular to the bottom wall (10).

6. phase separator (1) according to claim 5, comprising a partition wall formed between the first and second pipes (31), the partition wall extending into the first junction (41), the partition wall in the first junction (41) having a protruding portion (415) oriented in a direction opposite to a direction of flow between the first and second lines (21, 22).

7. phase separator (1) according to any one of claims 1 to 5, wherein the first junction (41) comprises a flow section continuously evolving between the first and second pipes (21, 22).

8. phase separator (1) according to any one of the preceding claims, wherein the first pipe (21) is in communication with an inlet port (11), the second pipe (22) being in communication with an orifice outlet (12), the inlet port and the outlet port being elevated relative to the bottom wall (10).

9. Electricity generating system (9), comprising:

a fuel cell (5) having a reagent outlet manifold and a reagent inlet manifold;

a phase separator (1) according to claim 8, the inlet orifice (11) being in communication with the reagent outlet manifold, and the outlet orifice (12) being in communication with the collector of reagent inlet.

10. System according to claim 9:

comprising a mixing junction (7) having an output connected to a fuel or oxidant inlet manifold of the fuel cell (5), and having a first input connected to a fuel or oxidizer supply (6) ;

in which the inlet (11) of the phase separator (1) is in communication with the fuel or oxidant outlet manifold and wherein the outlet port (12) is connected to a second inlet of the mixing junction (7).

11. System according to claim 9: comprising a mixing junction (7) having an output connected to the input port (11) of the phase separator (1), and having a first input connected to a fuel or oxidant supply (6);

in which the outlet port (12) of the phase separator (1) is in communication with the fuel or oxidant inlet manifold and wherein a second inlet of the mixing junction (7) is connected to the collector fuel outlet or oxidizer.

12. System according to claim 9:

comprising a mixing junction (73) having an outlet connected to an oxidant inlet manifold of the fuel cell (5), and having a first input connected to an oxidizer feed (71);

in which the inlet (11) of the phase separator (1) is in communication with the oxidizer outlet manifold and wherein the outlet port (12) is connected to a second inlet of the mixture (73).

The system of claim 12, further comprising a compressor having an input connected to the oxidizer outlet manifold and an output connected to said second input of the mixing junction (73).

14. System according to claim 9:

in which the outlet (12) of the phase separator (1) is in communication with the oxidizer inlet manifold;

comprising an expander (74) having an inlet connected to the oxidizer outlet manifold;

comprising a mixing junction (73) having an output connected to an input of the phase separator (1) having an input connected to an output of the expander (74) and having another input connected to an oxidizer supply (71) .

15. System (9) according to any one of claims 9 to 14, wherein said phase separator (1) has a wall in thermal contact with a flow of cooling fluid passing through the fuel cell (5).