Fuel cell exhaust system
By designing a condenser unit and an arc-shaped curved separation channel in the fuel cell exhaust system, the water in the fuel cell exhaust gas is separated by centrifugal force and gravity, the problem of low water separation efficiency in the existing system is solved, and the effect of efficient separation and smoke reduction is achieved.
Patent Information
- Application Number
- CN202411784336.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2023-12-07
- Filing Date
- 2024-12-06
- Publication Date
- 2025-06-10
AI Technical Summary
When the existing fuel cell exhaust system discharges fuel cell exhaust gas, it is difficult to efficiently separate the water in it, resulting in smoke or ground freezing in low temperature environments.
A fuel cell exhaust system is designed, including a condenser unit and a separation unit. The condenser unit condenses the water in the exhaust gas of the fuel cell, and the separation unit uses arc-shaped curved separation channels and separation chambers to separate the condensed water from the gaseous components through centrifugal force and gravity.
Through this system, most of the water can be efficiently separated from the fuel cell exhaust gas, reducing smoke formation, avoiding ground icy under low temperature environments, and effectively collecting and discharge of water.
Smart Images
Figure CN120127182A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a fuel cell exhaust system, which can in particular be used in combination with a fuel cell unit for providing electrical energy in a vehicle. Background Art
[0002] In order to generate electrical energy, an anode gas containing hydrogen (H 2 ) and a cathode gas containing oxygen such as air are supplied to the fuel cell unit. The fuel cell exhaust gas leaving the fuel cell, in particular the cathode exhaust gas, contains a relatively large proportion of water carried in the form of water vapor. When discharging the water-containing fuel cell exhaust gas into the environment, fog may be formed depending on the environmental conditions and there is also a possibility of causing icing on the ground, for example, under the vehicle. Summary of the Invention
[0003] The object of the present invention is to provide a fuel cell exhaust system by means of which the water contained in the fuel cell exhaust gas can be efficiently separated by structurally simple measures.
[0004] According to the present invention, this object is solved by a fuel cell exhaust system, in particular for a vehicle, which comprises a condenser unit for receiving the water-containing fuel cell exhaust gas discharged from the fuel cell unit and a separation unit arranged downstream of the condenser unit for separating the water condensed from the water-containing fuel cell exhaust gas supplied to the condenser unit, wherein the separation unit comprises a separation channel which is at least partially arcuately curved and is defined by a channel wall, and the separation channel is at least surrounded by a separation chamber in the region outside the arc, and a plurality of separation openings connecting the separation channel to the separation chamber are provided in the channel wall.
[0005] The fuel cell exhaust system constructed according to the present invention utilizes the centrifugal force occurring in the arcuately curved separation channel, by means of which the fuel cell exhaust gas and the water contained therein, which is condensed in the region of the condenser unit and is carried in the form of water droplets, i.e., in the liquid form, are radially loaded outwards. The condensed water accumulates or aggregates on the inner surface of the region outside the arc of the channel wall in the arcuately curved separation channel and enters the separation chamber via the separation openings provided there. Thus, most of the water contained in the fuel cell exhaust gas discharged from the fuel cell unit is separated from the gaseous components (in particular oxygen and nitrogen) of the fuel cell exhaust gas and can be returned, for example, to the fuel cell process or collected in the liquid form and discharged into the environment. Therefore, the degree of fog formation in the outlet region of the fuel cell exhaust system is greatly reduced.
[0006] For an efficient separation effect, the separation channel comprises an arc segment having an arc angle of at least 90°, preferably about 180°.
[0007] Since the condensed water is radially extruded outwards due to the centrifugal force with respect to the arcuate shape of the separation channel, it is particularly advantageous that a plurality of the separation openings, preferably all the separation openings, among the separation openings are arranged in the region of the outer half of the arc of the channel wall. In this way, the structural strength can be prevented from being weakened by the openings that are arranged in the radially inner region of the channel wall and do not contribute to the separation.
[0008] In order to discharge the separated water, preferably at least one discharge port can be arranged in the downstream end region of the separation chamber.
[0009] Here, in order to obtain a compact structural form, the downstream end region of the separation chamber with respect to the main flow direction of the fuel cell exhaust gas can be arranged in the region of the arcuate bending section of the separation channel.
[0010] In an alternative embodiment in which a relatively long separation channel can be used, it can be provided that a substantially linearly extending section of the separation channel is connected to the downstream end of the arcuate bending section of the separation channel, and the downstream end region of the separation chamber with respect to the main flow direction of the fuel cell exhaust gas is arranged in the region of the substantially linearly extending section of the separation channel.
[0011] In order to further support the separation of water from the fuel cell exhaust gas, it is proposed that at least one separation baffle is arranged at least on the outer arc region of the channel wall and extends into the separation channel. The water carried in the fuel cell exhaust gas in the form of water droplets can condense on such a separation baffle that protrudes radially inwards with respect to the arcuate bending configuration of the separation channel and is then radially exported outwards under the action of centrifugal force or / and gravity to the region of the channel wall and the separation openings provided therein.
[0012] For an efficient separation effect, it is proposed that at least one separation baffle is arranged downstream of the at least one discharge port.
[0013] In order to further support the export of the condensed water that is loaded towards the channel wall direction, at least one separation opening can be configured as a long hole that extends around the channel central axis of the separation channel in the circumferential direction.
[0014] Here, it is also advantageous for an efficient separation that at least one separation opening configured as a long hole is arranged downstream of the at least one discharge port.
[0015] If at least one separation baffle is arranged downstream of at least one separation opening configured as a long hole, a particularly efficient cooperation between the separation baffle on the one hand and the separation opening configured in the form of a long hole on the other hand can be achieved.
[0016] The invention further relates to a fuel cell system in a vehicle, preferably, which fuel cell system comprises at least one fuel cell unit and a fuel cell exhaust system configured according to the invention, and the fuel cell exhaust system receives fuel cell exhaust gas from the at least one fuel cell unit.
[0017] To support the discharge of water separated from the fuel cell exhaust gas, it is advantageous if the separation channel is bent downward in the height direction, i.e., in the vertical direction, such that the upstream end region of the separation channel is positioned higher in the height direction than the downstream end region of the separation channel. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] The invention is explained in detail below with reference to the drawings. The drawings are as follows:
[0019] Figure 1 A side view showing the fuel cell exhaust system;
[0020] Figure 2 Partially shown in longitudinal section Figure 1 of the fuel cell exhaust system;
[0021] Figure 3 Showing Figure 1 the separation unit of the fuel cell exhaust system;
[0022] Figure 4 Shown in perspective Figure 3 of the separation unit;
[0023] Figure 5 Showing Figure 3 the channel wall region of the separation unit;
[0024] Figure 6 A side view showing an alternative embodiment of the separation unit;
[0025] Figure 7 Showing a view corresponding to Figure 2 of an alternative embodiment of the separation unit;
[0026] Figure 8 Shown in principle Figure 7 of the separation unit along Figure 7 the sectional view taken along line VIII-VIII in
[0027] Figure 9 A side view showing an alternative embodiment of the separation unit;
[0028] Figure 10 A schematic diagram showing the fuel cell system. DETAILED DESCRIPTION OF THE INVENTION
[0029] In Figure 10In this case, the fuel cell system is generally designated by reference numeral 10 and can be used, for example, in a vehicle to supply electrical energy to a drive. The fuel cell system 10 includes, for example, a fuel cell unit 12 configured as a fuel cell stack, which has an anode region 14 and a cathode region 16. Hydrogen or a hydrogen-containing gas is supplied as anode gas A to the anode region 14. Oxygen or an oxygen-containing gas such as air is supplied as cathode gas K to the cathode region 16. An anode exhaust gas rich in hydrogen is generated in the anode region 14, while a cathode exhaust gas rich in water or water vapor is generated in the cathode region 16. These two gas flows can, for example, be combined and introduced as fuel cell exhaust gas B into a fuel cell exhaust system 18. The fuel cell exhaust gas B is discharged into the environment through the fuel cell exhaust system 18.
[0030] In order to avoid the formation of fog, especially at low ambient temperatures, when the fuel cell exhaust gas B is discharged from the fuel cell exhaust system 18 into the environment, measures are provided in the fuel cell exhaust system 18 to remove the water that causes fog formation from the fuel cell exhaust gas B.
[0031] The fuel cell exhaust system 18 includes one or more condenser units 20 through which the fuel cell exhaust gas B can flow. In the condenser unit 20, a condensation process is triggered, for example, by the thermal interaction of the fuel cell exhaust gas B with relatively cold ambient air, which causes most of the water contained in the fuel cell exhaust gas B as steam, i.e., as a gas, to condense and be carried in the fuel cell exhaust gas B leaving the condenser unit 20 in the form of water droplets. Downstream of the condenser unit 20 and in the separation unit 22 described in detail below with reference to Figures 1 to 9 the condensed water or most of the condensed water is separated from the remaining gaseous components of the fuel cell exhaust gas B (i.e., mainly oxygen and nitrogen), collected and, for example, returned to the fuel cell process or discharged into the environment in liquid form.
[0032] In Figures 1 to 5 the separation unit 22 shown in a first embodiment includes an arcuate pipe section 24, which is connected, for example, to a section 26 extending substantially linearly leading from the condenser unit 20. The arcuate pipe section 24 forms, for example, an arc segment with an arc angle of approximately 180°, which means that the fuel cell exhaust gas B flowing through the arcuate pipe section 24 undergoes a flow deflection of approximately 180°. A pipe section 28 extending substantially linearly can be connected, for example, to the arcuate pipe section 24, in which the fuel cell exhaust gas B flows substantially in the opposite direction to the flow direction in the pipe section 26 or also in the opposite direction to the flow direction upstream of the condenser unit 20.
[0033] In the arcuate tube section 24, a separation channel 30 is formed through which the fuel cell exhaust gas B flows approximately along the channel central axis M in the main flow direction of the fuel cell exhaust gas. In this separation channel, based on the turning of the fuel cell exhaust gas B and the centrifugal force occurring therein, not only the gaseous components of the fuel cell exhaust gas B but also the water droplets W contained therein are radially outwardly loaded. This results in, on the one hand, a radially outward fluid separation in the inner arc region 32 of the channel wall 34 of the arcuate tube section 24 or surrounding the separation channel 30, which supports the radially outward loading of the water droplets W carried in the fuel cell exhaust gas B. These water droplets thus accumulate more strongly on the outer arc region 36 of the channel wall 34 and also move along the outer arc region 36 of the channel wall 34 in the flow direction of the fuel cell exhaust gas B.
[0034] The channel wall 34 of the arcuate tube section 24 is partially surrounded by a separation chamber wall 38. This particularly relates to the outer arc region or the outer arc half of the channel wall 34 and the downstream half of the substantially arcuate tube section 24. In the region covered by the separation chamber wall 38, the channel wall 34 and the separation chamber wall 38 together define a separation chamber generally designated by the reference numeral 40. In the region where the separation channel 30 is covered by the separation chamber 40 in its outer arc or downstream region, a plurality of separation openings 42 are provided in the channel wall 34. The separation openings 42 are substantially located in the region of the outer arc half of the channel wall 34, that is, in the region where the water droplets W accumulated based on the action of the centrifugal force and based on the flow direction of the fuel cell exhaust gas B in the separation channel 30 are radially outwardly loaded.
[0035] The water droplets W accumulated on the inner side of the channel wall 34 or the water separated from the fuel cell exhaust gas B in the condenser unit 20 enter the separation chamber 40 via the separation openings 42. Since the arcuate tube section 24 is positioned such that it extends radially downward starting from a substantially straight channel section 26, so that the downstream end region 44 of the separation channel 30 is substantially below the upstream end region 46 of the separation channel 30 in the height direction H or the vertical direction, this results in the downstream end region 48 of the separation chamber 40 also being positioned below in the height direction. The water entering the separation chamber 40 via the separation openings 42 flows downward under the action of gravity into the region of the discharge port 50.
[0036] The discharge port 50 provided on the downstream end region 48 and / or provided on the region of the separation chamber 40 located at the lowest point in the height direction H can in principle be open, so that the liquid water entering its region can leave the separation chamber 40 without the risk of forming smoke and drip onto the ground located below the fuel cell exhaust system 18. Alternatively, the discharge port 50 can be closed by a valve unit, so that the water can be discharged from the separation chamber 40 at a defined time point and, for example, also be sent back to the fuel cell unit 12 through a corresponding pipeline.
[0037] InFigure 6 In the variant embodiment shown, the separation channel 30 (as indicated by the dashed line) extends beyond the 180° arc provided by the arcuate tube section 24, for example, into the region of the linearly extending tube section 28 or into a correspondingly extended section of the arcuate tube section 24. The separation chamber 40 also extends beyond the arc section of the arcuate tube section 24 into this linearly extending region, so that not only the separation channel 30 but also the separation chamber 40 can provide a larger volume or a longer flow path, thereby enabling further improved separation characteristics. The region provided with the separation opening 42 can also extend into the linearly extending region that provides the downstream end region 44 of the separation channel 30 or the channel wall 34 surrounding the separation channel and enclosing the separation channel 30 or the tube section 24.
[0038] Figures 7 to 9 Another embodiment of the separation unit 22 is shown, in which the separation of water or water droplets from the fuel cell exhaust gas B is supported by special structural measures.
[0039] Figure 7 and Figure 8 A separation baffle 52 extending into the separation channel 30 is shown downstream of the discharge port 50. The separation baffle 52 extends radially inward from the outer arc region 36 of the channel wall 34 with respect to the channel central axis M and thus constitutes a flow obstacle for the water droplets W still carried by the fuel cell exhaust gas B in the outer arc region of the separation channel 30. These water droplets impinge on the separation baffle 52. Since the separation baffle 52 is positioned on the downstream end region 44 of the separation channel 40, the water accumulated on the separation baffle 52 moves radially outward or downward based on gravity. The separation opening 42 extending as a slot in the circumferential direction around the channel central axis M is adjacent to the upstream of the separation baffle 52. Preferably, the extension length of the separation opening 42' configured as a slot is approximately the same as the extension length of the separation baffle 52 around the channel central axis M. Therefore, the water accumulated on the separation baffle 52 can flow unobstructed downward in the height direction through the separation opening 42' configured as a slot into the separation chamber 40 and flow towards the discharge port 50.
[0040] In the fuel cell exhaust system constructed according to the present invention, a separation chamber covering or surrounding the separation channel through which the fuel cell exhaust gas flows is formed by a locally double-wall design. The water condensed in the condenser unit and separated from the gaseous components of the fuel cell exhaust gas accumulates in this separation chamber due to the outward loading of the water droplets (i.e., towards the outer arc region of the channel wall surrounding the separation channel). Therefore, no other measures for separating water that may cause flow blockage are required. In the fuel cell exhaust system constructed according to the present invention, only the forces acting on the condensed water when passing through the separation unit, namely centrifugal force on the one hand and gravity on the other hand, are utilized to efficiently separate the condensed water from the gaseous components of the fuel cell exhaust gas.
Claims
1. A fuel cell exhaust system, in particular a fuel cell exhaust system for a vehicle, the fuel cell exhaust system comprising a condenser unit (20) for receiving fuel cell exhaust gas (B) containing water discharged from a fuel cell unit and a separation unit (22) arranged downstream of the condenser unit (20) for separating water condensed from the fuel cell exhaust gas (B) containing water supplied to the condenser unit (20), wherein: The separation unit (22) comprises a separation channel (30) which is at least partially curved in an arc shape and is defined by a channel wall (34); the separation channel (30) is surrounded by a separation chamber (40) at least in an arc outer region; and a plurality of separation openings (42) connecting the separation channel (30) and the separation chamber (40) are arranged in the channel wall (34).
2. The fuel cell exhaust system according to claim 1, characterized in that: The separation channel (30) comprises an arc segment having an arc angle of at least 90°, preferably about 180°.
3. The fuel cell exhaust system according to claim 1 or 2, characterized in that: A plurality of the separating openings (42), preferably all of the separating openings (42), are arranged in the region of the arc-outer half of the channel wall (34).
4. The fuel cell exhaust system according to any one of claims 1 to 3, characterized in that: Preferably, at least one outlet opening (50) is provided in the downstream end region (48) of the separation chamber (40).
5. The fuel cell exhaust system according to claim 4, characterized in that: The downstream end region (48) of the separation chamber (40) with respect to the main flow direction of the fuel cell exhaust gas is arranged in the region of the arc-shaped curved section of the separation channel (30).
6. The fuel cell exhaust system according to claim 4, characterized in that: A substantially straight section of the separation channel (30) is connected to the downstream end of the arc-shaped curved section of the separation channel (30), and a downstream end region (48) of the separation chamber (40) with respect to the main flow direction of the fuel cell exhaust gas is arranged in the region of the substantially straight section of the separation channel (30).
7. The fuel cell exhaust system according to any one of claims 1 to 6, characterized in that: At least one separation baffle (52) extending into the separation channel (30) is arranged at least on the arc outer side region (36) of the channel wall (34).
8. The fuel cell exhaust system according to claim 7 and claim 4, characterized in that: At least one separation baffle (52) is disposed downstream of the at least one discharge opening (50).
9. The fuel cell exhaust system according to any one of claims 1 to 8, characterized in that: At least one separating opening (42') is designed as an elongated hole extending in the circumferential direction around a channel center axis (M) of the separating channel (30).
10. The fuel cell exhaust system according to claim 9, characterized in that: At least one separating opening (42') designed as an elongated hole is arranged downstream of the at least one outlet opening (50).
11. The fuel cell exhaust system according to claim 7 and claim 10, characterized in that: At least one separating baffle (52) is arranged downstream of at least one separating opening (42') which is designed as an elongated hole.
12. A fuel cell system, preferably a fuel cell system in a vehicle, comprising at least one fuel cell unit (12) and a fuel cell exhaust system (18) according to any one of claims 1 to 11, wherein the fuel cell exhaust system receives fuel cell exhaust gas (B) from the at least one fuel cell unit (12).
13. The fuel cell system according to claim 12, characterized in that: The separation channel (30) is bent downward in the height direction (H) so that the upstream end region (46) of the separation channel (30) is positioned higher than the downstream end region (44) of the separation channel (30) in the height direction (H).