JP7222322B2 - gas-liquid separator - Google Patents

Description

The present invention relates to the technology of gas-liquid separators used to separate water from the gas discharged from the anode of a fuel cell.

As a gas-liquid separator having the above configuration, Patent Document 1 discloses a technique of a gas-liquid separator having a gas-liquid separator main body having a water storage portion at the bottom and an inlet and an outlet at positions higher than the water storage portion. is described.

In the gas-liquid separator described in Patent Document 1, a vertical wall-shaped collision wall is provided inside the gas-liquid separator main body and at an intermediate position between the inlet and the outlet, and the rebound is reduced above the water reservoir. Equipped with a board. With this configuration, the water-containing gas introduced from the inlet collides with the collision wall to separate the water contained in the gas, and the separated water is stored in the reservoir. Then, the gas from which the water is separated is discharged from the outlet.

JP 2017-147159 A

A fuel cell generates electricity by supplying hydrogen gas to the anode side and supplying oxygen-containing air to the cathode side. Further, the anode off-gas discharged from the anode side of the fuel cell contains unreacted hydrogen and water. A gas-liquid separator is provided in the reducing flow path to separate and remove water contained in the anode off-gas to be reduced.

In the gas-liquid separator of Patent Document 1, the anode off-gas horizontally discharged from the fuel cell stack is received inside the main body through the inlet, and the anode off-gas collides with the plate-like collision wall portion inside the main body. By reducing the flow velocity, the water contained in the anode off-gas is separated as the flow velocity is reduced, and the water contained in the anode off-gas is separated using the change in gas flow when the gas is passed through the lower end of the collision wall. It separates further.

Further, in the gas-liquid separator of Patent Document 1, the outlet is arranged at a relatively high position so that water in the gas can be separated when the anode off-gas flows through the outlet. As described above, in the gas-liquid separator of Patent Document 1, since the anode off-gas received from the inlet is made to flow in the horizontal direction and collide with the vertical impingement wall, part of the anode off-gas impinges on the impingement wall. There is also a possibility that the particles will flow without colliding with each other, and an improvement in the separation performance has been desired. In particular, since the lead-out portion is formed at a high position, the size of the gas-liquid separator is increased, and there is room for improvement.

Furthermore, a gas-liquid separator is provided with a drainage channel for discharging water from a water storage part (reservoir in Patent Document 1) and an on-off valve (drainage valve in Patent Document 1) that opens and closes this drainage channel. Considering this, it is conceivable to form the drainage channel with a small diameter like an orifice in order to suppress the inconvenience of discharging the anode off-gas containing unreacted hydrogen after the on-off valve is opened and the water is discharged.

However, when a fuel cell vehicle (FCV) is stopped in a cold region and the power generation of the fuel cell is stopped, water freezes inside the drainage channel and this is caused by a small-diameter drainage channel. This leads to hindrance to power generation of the fuel cell later. Therefore, when stopping the power generation of the fuel cell in a cold region, not only the process of discharging the water in the reservoir by opening the on-off valve, but also the gas not containing hydrogen is supplied to the inside of the gas-liquid separator. A process of removing water droplets inside the gas-liquid separator has also been performed by scavenging. However, it has been difficult to eliminate the phenomenon that water droplets remain on the inner surface of the gas-liquid separator even when water is discharged and scavenging is performed.

For these reasons, there is a demand for a gas-liquid separator that can be miniaturized without lowering the water separation performance of the water-containing gas.

The gas-liquid separator according to the present invention is characterized by a housing, a gas-liquid separator provided inside the housing for separating water from the water-containing gas, and a bottom portion of the housing in the direction in which gravity acts. a water storage portion for storing water separated by the gas-liquid separation portion; and a cylindrical separation space extending along a central axis in which the gas-liquid separation portion faces a direction in which gravity acts. an introduction pipe for supplying the water-containing gas to the separation space; and a drain opening for feeding the water separated from the water-containing gas in the separation space and the dewatered gas from which the water is separated, and the introduction pipe feeds the water-containing gas to the central axis. The direction of supply is set so as to rotate around, and the collision wall is formed with an extension length shorter than the total length of the separation space in the direction along the central axis, so that the end of the collision wall in the extension direction is formed. and a second end wall formed at a position facing the first end wall, a merging space is formed, and the drain opening is formed at the bottom of the merging space.

According to this characteristic configuration, when the water-containing gas is supplied from the introduction pipe to the gas-liquid separation part, it turns around the central axis so as to collide with the collision wall inside the separation space, and along the central axis to move. As a result, when the water-containing gas collides with the collision wall, the water contained in the water-containing gas is separated, and the separated water and the dehydrated gas from which the water is separated pass through the extending direction end of the collision wall, reach the confluence space. The water and the dehydrated gas are sent downward from the drain opening at the bottom of the confluence space, the water drops into the water reservoir and is collected, and the dehydrated gas is discharged from the housing.
That is, in this configuration, since the collision walls are arranged in a laterally extending posture, it is possible to reduce the size in the vertical direction compared to, for example, a case in which a plurality of collision walls are arranged vertically. In addition, when the water-containing gas is sent sideways, the water-containing gas is swirled around the central axis and collides with multiple collision walls, so the water separation performance is improved and the size in the horizontal direction can be reduced, resulting in an overall compact size. It also realizes
As a result, a gas-liquid separator that can be miniaturized without lowering the water separation performance of the water-containing gas was constructed.

As another configuration, the inner wall on the bottom side of the separation space may be formed in an inclined posture that is lowered from the first end wall toward the drain opening.

According to this, the water separated from the water-containing gas in the separation space flows by its own weight along the inner wall on the bottom side toward the drain opening, and water droplets do not remain inside the separation space.

As another configuration, when a plurality of the collision walls are provided, the water-containing gas supplied to the separation space is guided by the central axis so that the water-containing gas supplied to the separation space is sequentially guided to the collision walls on the downstream side in the turning direction. A posture in a direction along which the collision wall is directed may be set, and the plurality of collision walls may be formed in an inclined posture in which the upper surface opposite to the direction in which gravity acts becomes lower as the position approaches the confluence space.

According to this, the water-containing gas supplied to the separation space turns around the central axis while sequentially contacting the plurality of collision walls. Furthermore, the upper surfaces of the plurality of collision walls, which are opposite to the direction in which the gravity acts, are formed with a lower inclination toward positions closer to the merging space. Even if water droplets remain attached, the water droplets on the upper surface flow toward the merging space and can be collected in the water reservoir through the drain opening.

As another configuration, the drain opening may have a slit-shaped portion that is an opening extending in a direction along the central axis.

According to this, since the drain opening has a slit-shaped portion, the gas-liquid separator is provided in the fuel cell vehicle (FCV), and the gas-liquid separator is used when the fuel cell vehicle stops on a slope. Water in the separation space can be reliably discharged even in an inclined situation.

As another configuration, a communication portion communicating with the collision wall in the thickness direction may be formed at a base end portion of the collision wall on the inner wall side of the separation space.

According to this, the water droplets remaining in the separation space can flow through the communicating portion of the impingement wall, and the problem of water droplets remaining in the separation space can be eliminated.

It is a perspective view of a gas-liquid separator with a part notched. It is a front view of a gas-liquid separator. 3 is a cross-sectional view taken along line III-III of FIG. 2; FIG. FIG. 3 is a plan view of the gas-liquid separator with a part cut away; It is a longitudinal cross-sectional view of a gas-liquid separator. It is a longitudinal cross-sectional view of a gas-liquid separator. FIG. 4 is a cross-sectional view showing the shape of a drain opening; It is sectional drawing of the gas-liquid separation part of another embodiment (a).

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings.
[Basic configuration]
1 to 6 show a gas-liquid separator A for separating water contained in anode off-gas (an example of water-containing gas) discharged from the anode side of a fuel cell mounted on a fuel cell vehicle (FCV). there is The gas-liquid separator A includes an inlet pipe 1 , an outlet 2 , a gas-liquid separation section 3 and a water storage section 4 in a housing H. Further, an electromagnetic on-off valve 5 for controlling the discharge of water stored in the water reservoir 4 is provided outside H of the housing.

A fuel cell realizes power generation by supplying a humidified anode gas (fuel gas) containing hydrogen gas to the anode side and supplying a cathode gas (oxidant gas) containing oxygen and air to the cathode side. . The reason for humidifying the anode gas is to wet the anode side of the fuel cell.

Since power generation is performed in this manner, the anode off-gas (an example of water-containing gas) discharged from the anode side contains unreacted hydrogen gas and water. In the fuel cell, in order to reuse unreacted hydrogen gas in part of the anode gas supplied to the anode side, a gas-liquid separator A is provided in the reduction path for returning the anode off-gas to the anode side.

That is, the gas-liquid separator A is supplied with the anode off-gas as a water-containing gas, separates the water contained in the anode off-gas, recovers it in the water storage unit 4, and the anode off-gas as the dehydrated gas from which the water is separated. is discharged from the discharge port 2. The anode off-gas discharged in this way is supplied to the anode side of the fuel cell, thereby realizing reuse of unreacted hydrogen gas.

[Housing, inlet, outlet]
As shown in FIGS. 1 to 3 and 6, the housing H includes an upper flange portion 11f of an upper housing 11 having an introduction pipe 1, a discharge port 2, and a gas-liquid separation portion 3, a water storage portion 4, and an electromagnetic on-off valve. 5 is fastened with a plurality of fastening bolts 6 to the lower flange portion 15f of the lower housing 15. As shown in FIG. The upper flange portion 11f and the lower flange portion 15f may be fastened by other means such as welding using ultrasonic waves.

The upper housing 11 and the lower housing 15 are made of a resin material, and an internal space S is formed between them when the upper housing 11 and the lower housing 15 are fastened together. The upper housing 11 and the lower housing 15 may be made of metal such as aluminum.

As shown in FIG. 3, the upper housing 11 is provided with a gas-liquid separator 3 in a separation space T separated from the internal space S. As shown in FIG. Details of the gas-liquid separator 3 will be described later.

As shown in FIGS. 1 to 6, the separation space T is a space formed inside a bulging portion 12 integrally formed to bulge upward in the upper housing 11 . The separation space T extends along a central axis X (an imaginary axis at the center of the separation space T) that is lateral to the direction in which gravity acts. A tubular introduction pipe 1 is formed in the bulging portion 12 so as to intersect the central axis X so as to communicate with the separation space T and extend in the horizontal direction. The separation space T is formed in the bulging portion 12 between the outer wall 12W (an example of the first wall portion) and the closing plate 13 (an example of the second wall portion) located opposite thereto. .

The introduction pipe 1 has an introduction path 1R for feeding the anode off-gas formed therein, and the direction of supply by the introduction pipe 1 is set so that the anode off-gas is fed above the separation space T in the horizontal direction. By setting this supply direction, the anode off-gas swirls counterclockwise about the central axis X in the separation space T, as indicated by the arrow in FIG.

As shown in FIGS. 1 and 6, a closing plate 13 (an example of an end wall) is detachably fixed by a plurality of screws 13a at a position of the bulging portion 12 that closes the side opening 12a of the separation space T. ing. Although the closing plate 13 is made of a resin material, it may be made of a metal such as aluminum. Further, the closing plate 13 is not limited to being fixed by a plurality of screws 13a, and may be fixed by ultrasonic waves or the like. It should be noted that the closing plate 13 cannot be detached when it is fixed in this way.

As shown in FIGS. 3 and 4, the discharge port 2 is formed in the internal space S of the bulging portion 12 . The discharge port 2 is arranged at a position lower than the introduction pipe 1 in a posture orthogonal to the extending direction of the introduction pipe 1 . Although the position of the discharge port 2 is not limited to a position lower than the introduction pipe 1, it is preferably a position lower than the introduction pipe 1.

[Housing, reservoir]
As shown in FIGS. 3 and 6, the lower housing 15 is integrally formed with a bottom wall portion 16 projecting downward at the center. A water storage part 4 is configured by the space. An internal space S is formed by combining the space above the water reservoir 4 and the space excluding the separation space T of the upper housing 11 .

As shown in FIGS. 1, 2, and 6, a drainage block 17 projecting laterally is integrally formed at the lower end of the bottom wall portion 16. As shown in FIG. Inside the drain block 17, a drain channel 17a communicating with the bottom of the water storage part 4 is formed, and on the outer surface of the drain block 17, a drain pipe 17b for discharging water from the drain channel 17a is formed. ing. Furthermore, the drainage block 17 is provided with an electromagnetic on-off valve 5 for controlling the discharge of water flowing through the drainage channel 17a.

When the electromagnetic on-off valve 5 is opened and the water in the water reservoir 4 is discharged, the discharge of the anode off-gas containing unreacted hydrogen is suppressed, and discharge of a constant flow rate is possible. It is formed with a small diameter like an orifice.

As shown in FIG. 6, the electromagnetic on-off valve 5 includes a valve body 5a held in a position to close the drainage channel 17a by a spring biasing force and an electromagnetic valve that operates the valve body 5a against the spring biasing force when energized. It has a solenoid 5b and a sealing film 5c made of resin or rubber that abuts against the outer end of the drainage channel 17a.

Due to this configuration, when the electromagnetic solenoid 5b is not driven, the valve body 5a is held in the closed position by the spring biasing force, and the seal film 5c closes the outlet of the drainage channel 17a, so that water is stored in the water reservoir 4. be. On the other hand, when the electromagnetic solenoid 5b is driven, the seal film 5c is separated from the outlet of the drainage channel 17a as the valve body 5a is actuated, and the water in the reservoir 4 flows from the drainage channel 17a to the drainage pipe 17b. flows and is discharged to the outside.

[Gas-liquid separator]
As shown in FIGS. 3, 5, and 6, the introduction path 1R of the introduction pipe 1 communicates with a portion of the separation space T that continues to the outer wall 12W (one end side in the direction along the central axis X). ing. The separation space T has a laterally open portion facing the outer wall 12W, and the open portion is closed by the closing plate 13 . Thus, the closing plate 13 is arranged at a position facing the outer wall 12W. The introduction pipe 1 is formed in a posture orthogonal to the central axis X. As shown in FIG.

The gas-liquid separator 3 has a plurality of collision walls 21 . That is, the collision wall 21 protrudes from the outer wall 12W of the separation space T by a predetermined width in the direction of the central axis X, and extends along the central axis X in the separation space T in the direction along the central axis X. It is formed with an extension length shorter than the full length. Further, a merging space Ta is formed between the ends of the plurality of collision walls 21 in the extending direction and the closing plate 13, and a drain opening 22 is formed at the bottom of this merging space Ta.

As shown in FIG. 3, the anode off-gas (water-containing gas) supplied to the separation space T is sequentially guided to the collision wall 21 on the downstream side in the turning direction. The posture of the collision wall 21 is set.

In the gas-liquid separator A having this configuration, assuming that the inner surface of the bottom of the separation space T and the upper surface of the collision wall 21 are in a horizontal posture, the power generation in the fuel cell stops and the anode off-gas is released into the air. When the water is not supplied to the liquid separator A, it is conceivable that water droplets adhere to and remain on the upper surfaces of the plurality of collision walls 21 .

In order to eliminate such inconvenience, as shown in FIGS. 5 and 6, the inner wall 12b on the bottom side of the separation space T and the upper surface of the plurality of collision walls 21 on the side opposite to the direction in which the gravity acts are provided. , and is formed in an inclined posture in which the position closer to the drain opening 22 in the confluence space Ta becomes lower. The angle at which the inner wall 12b of the separation space T is inclined is set to about 8° with respect to the horizontal, but may be any angle.

As a result, even when water droplets adhere to the inner wall 12b on the bottom side of the separation space T and the upper surfaces of the plurality of collision walls 21, these water droplets flow toward the confluence space Ta and drain at the bottom of the separation space T. It is discharged downward through the opening 22 and collected in the water reservoir 4 .

As shown in FIG. 7, the drain opening 22 is arranged adjacent to the opening body 22a extending in the circumferential direction of the merging space Ta at the bottom of the merging space Ta at the bottom of the separation space T. and a slit-like portion 22b formed in a direction extending along the central axis X between the pair of collision walls 21. As shown in FIG.

[Water separation by gas-liquid separator and effects of embodiment]
With such a configuration, as shown in FIGS. 3 and 6, in the gas-liquid separation section 3, the anode off-gas is supplied from the introduction pipe 1 to the outer end side of the upper housing 11 in the lateral direction with respect to the separation space T. In this case, the anode off-gas moves in the direction of the closing plate 13 on the side opposite to the supply position while rotating around the central axis X inside the separation space T.

Further, as the anode off-gas swirls inside the separation space T, the anode off-gas comes into contact with the plurality of collision walls 21 in such a manner that it collides with them sequentially. Due to this contact, the water contained in the anode off-gas is turned into droplets on the surface of the collision wall 21 . Furthermore, even the anode off-gas that does not come into contact with the collision wall 21 forms water droplets due to the centrifugal force associated with the swirl and the change in the direction of motion.

A part of the anode off-gas eventually collides with the inner surface of the closing plate 13, and the flow direction of the anode off-gas is changed downward by the closing plate 13. Water contained in the anode off-gas separates and forms water droplets also at the site. As shown in FIGS. 5 and 6, the opening-side inner wall 12c located on the bottom side of the side opening 12a is formed in an inclined posture that becomes lower as the position closer to the drain opening 22 approaches. Water droplets formed on the inner surface of the drain opening 22 also flow.

The water that has flowed into the confluence space Ta and the dehydrated anode off-gas are discharged from the drain opening 22 , and the water is stored in the water storage section 4 below the drain opening 22 . On the other hand, the dehydrated anode off-gas that has passed through the drain opening 22 flows toward the discharge port 2 located higher than the drain opening 22 in the internal space S, and is discharged from the discharge port 2 . If the anode off-gas flowing toward the discharge port 2 contains water, it is separated by its weight when flowing upward in the internal space S and collected in the water reservoir 4 .

As described above, in the gas-liquid separator A, the anode off-gas is not simply moved laterally (horizontally), but is brought into contact with the plurality of collision walls 21 by swirling around the central axis X in a lateral posture, thereby increasing efficiency. water separation. Therefore, for example, it is possible to reduce the size in the vertical direction compared to a structure in which a plurality of collision walls 21 are arranged vertically, and in addition, it is possible to reduce the size in the horizontal direction. is realized.

In this gas-liquid separator A, a control device such as an ECU estimates the amount of water stored in the water storage portion 4 from the amount of power generated by the fuel cell, and when the amount of water estimated in this way needs to be discharged, the control device is controlled to open the electromagnetic on-off valve 5 and discharge water. The gas-liquid separator A may be configured to include a sensor for detecting the amount of water stored in the water storage section 4 and open the electromagnetic on-off valve 5 based on the detection result of this sensor.

Further, when the fuel cell vehicle stops in a cold region and water remains in the drainage channel 17a when the power generation by the fuel cell is stopped, the water freezes inside the drainage channel 17a, and the water is frozen in the drainage channel 17a. It was also thought that the fuel cell would interfere with power generation. In order to solve such a problem, the electromagnetic on-off valve 5 is opened to discharge the water in the reservoir 4 when the power generation of the fuel cell is stopped in cold regions.

In particular, since the inner wall 12b on the bottom side of the separation space T and the upper surfaces of the plurality of collision walls 21 are inclined, and the opening-side inner wall 12c is formed on the bottom side of the side opening 12a in an inclined orientation, power generation Even if water droplets adhere to the plurality of collision walls 21, etc. of the separation space T when the gas-liquid separator A is stopped, the water droplets can flow out to the drain opening 22 by their own weight before the temperature of the gas-liquid separator A drops below freezing. It is possible. Since the water discharged from the drain opening 22 in this way is discharged from the water storage section 4 to the outside, there is no problem that the water freezes inside the drain passage 17a.

[Another embodiment]
The present invention may be configured as follows other than the above-described embodiments (components having the same functions as those of the embodiments are given the same numbers and symbols as those of the embodiments).

(a) As shown in FIG. 8, a communication hole 21a (an example of a communication portion) penetrating through the collision wall 21 in the thickness direction is formed in the base end portion of the collision wall 21 on the inner wall side of the separation space T. As shown in FIG. By forming the communication hole 21a in the collision wall 21 in this manner, the water droplets remaining inside the separation space T flow through the communication hole 21a and are easily discharged.

In this alternative embodiment (a), the communicating hole 21a is shown as the communicating portion, but for example, a cutout space (not shown) obtained by cutting out a part of the collision wall 21 can be formed as the communicating portion. . As described in the embodiment, the plurality of collision walls 21 are formed in an inclined posture such that the position closer to the confluence space Ta is lower, so even if water droplets exist on the upper surface of the collision walls 21, they can be discharged. However, the formation of the communication hole 21a and the cutout space makes it possible to discharge water more satisfactorily.

(b) Using a water-repellent resin material for the material of the housing H, or applying a water-repellent paint to the inner surface of the housing H; As a result, the phenomenon of water droplets remaining inside the housing is suppressed, and the inconvenience of the water droplets freezing inside the drainage channel 17a is suppressed.

(c) Contrary to the embodiment, the position where the separation space T is supplied from the introduction pipe 1 may be set on the lower side. In this case, the direction in which the anode off-gas swirls is set opposite to that in the embodiment. Even if the direction of introduction is set in this way, the anode off-gas can be swirled about the central axis X and the water can be separated satisfactorily.

(d) The discharge port 2 is formed as a vertical opening so as to discharge the anode off-gas upward. By forming in this way, it can be expected that water contained in the anode off-gas will be separated by gravity when the anode off-gas flows upward.

INDUSTRIAL APPLICABILITY The present invention can be used for a gas-liquid separator that separates water from gas discharged from the anode of a fuel cell.

1 Introduction pipe 3 Gas-liquid separator 4 Water reservoir 12W External wall (first end wall)
13 Closure plate (second end wall)
21 collision wall 21a communicating hole (communicating portion)
22 Drain opening 22b Slit-shaped portion H Housing T Separation space Ta Merging space X Central axis

Claims (5)

a housing;
a gas-liquid separator provided inside the housing for separating water from water-containing gas;
a water storage part provided at the bottom of the housing in the direction of gravity, and storing water separated by the gas-liquid separation part;
The gas-liquid separation unit has a cylindrical separation space extending along a central axis in a lateral orientation with respect to a direction in which gravity acts; an introduction pipe for supplying water-containing gas to the separation space; at least one impingement wall projecting with a predetermined width in the direction of the central axis and extending along the central axis from a first end wall of the separation space; water separated from the water-containing gas in the separation space; a drain opening for delivering dehydrated gas from which water has separated;
The supply direction of the introduction pipe is set so as to swirl the water-containing gas around the central axis, and the collision wall is formed to have an extension length shorter than the full length of the separation space in the direction along the central axis. As a result, a merging space is formed between the end of the collision wall in the extending direction and the second end wall formed at a position facing the first end wall. A gas-liquid separator in which said drain opening is formed. 2. The gas-liquid separator according to claim 1, wherein the inner wall of the separation space on the bottom side is formed in an inclined posture that is lowered from the first end wall toward the drain opening. When a plurality of the collision walls are provided, the posture in a direction view along the central axis is such that the collision walls sequentially guide the water-containing gas supplied to the separation space to the collision walls on the downstream side in the turning direction. is set and
3. The gas-liquid separator according to claim 1 or 2, wherein, in the plurality of collision walls, an upper surface opposite to a direction in which gravity acts is formed in an inclined posture such that the closer to the confluence space, the lower the upper surface becomes. 4. The gas-liquid separator according to any one of claims 1 to 3, wherein the drain opening has a slit-shaped portion extending in the direction along the central axis. The gas-liquid separation according to any one of claims 1 to 4, wherein a communicating portion communicating in the thickness direction of the collision wall is formed at a base end portion of the separation space of the collision wall on the inner wall side. vessel.

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