JP7283168B2 - gas-liquid separator - Google Patents

Description

The present invention relates to a gas-liquid separator for separating water from gas discharged from a fuel cell.

As a gas-liquid separator having the above configuration, Patent Document 1 discloses that a gas-liquid separator main body having a water storage portion at the bottom is configured, and an inlet and an outlet are provided at a position higher than the water storage portion of the gas-liquid separator main body. ing.

In this patent document 1, inside the gas-liquid separator main body, a vertical wall-shaped collision wall is provided at an intermediate position between the inlet and the outlet, and a rebound reduction plate is provided above the water reservoir (reservoir in the document). ing. With this configuration, the gas introduced from the inlet collides with the collision wall to separate the water, the separated water is stored in the water reservoir, and the gas after the water is separated by collision with the collision wall is guided. discharged from the outlet.

Furthermore, as a gas-liquid separator having the above configuration, Patent Document 2 discloses that a suction pipe is provided in the upper part of the chamber, a discharge pipe is provided in the upper surface of the chamber, a drain pipe is provided in the lower end of the chamber, and a screen (filter) is provided inside the chamber. I have.

In this document, the chamber consists of an upper swirl chamber and a lower collection chamber, with a screen in between. The suction pipe is configured to supply fluid tangentially to the vortex chamber to create a vortex within the chamber and separate water from the fluid. In this configuration, the water separated from the fluid is filtered through the screen and then discharged from the drain pipe, and the fluid from which the water is separated is discharged from the discharge pipe.

JP 2017-147159 A JP 2016-72183 A

A fuel cell generates electricity by supplying hydrogen gas to the anode side of the stack and supplying air (oxygen) to the cathode side of the stack. Further, during power generation, the hydrogen contained in the anode off-gas from the anode side is recycled and returned to the anode side. A gas-liquid separator is used.

In a fuel cell, oxygen and hydrogen react on the cathode side to generate water during power generation, so the cathode off-gas contains a large amount of water, and it is desirable to discharge the cathode off-gas after removing the water. It is rare.

Therefore, it is conceivable to use the gas-liquid separator described in Patent Document 1 or Patent Document 2 in order to remove the water contained in the cathode off-gas. Since the flow of air is complicated, the pressure loss is relatively large. In addition, although miniaturization is required for fuel cells provided in automobiles, the gas-liquid separator described in Patent Document 1 or Patent Document 2 has a complicated structure, which makes it difficult to miniaturize.

For these reasons, there is a demand for a small-sized gas-liquid separator that does not greatly restrict the flow of cathode off-gas from the fuel cell and that separates water satisfactorily.

The characteristic configuration of the gas-liquid separator according to the present invention includes an introduction section for receiving cathode off-gas discharged from a fuel cell, a discharge section for discharging cathode off-gas, and a boundary between the introduction section and the discharge section, a recovery unit configured to separate and recover water contained in the cathode off-gas, wherein a cathode off-gas introduction channel in the introduction unit and a cathode off-gas discharge channel in the discharge unit are connected to the discharge from the introduction channel; The separation wall separates the water by contacting the cathode off-gas from the introduction channel at this offset position , and feeds the cathode off-gas obliquely upward. It is characterized in that it has a sloping portion and the water storage space of the recovery section is arranged below the separation wall.

According to this characteristic configuration, the cathode off-gas discharged from the fuel cell flows from the introduction section to the discharge section after coming into contact with the separation wall. Water contained in the cathode off-gas is separated by contacting the cathode off-gas with the separation wall, and is stored in the water storage space of the recovery unit. In particular, the cathode off-gas flows through the introduction channel and the discharge channel that are arranged in a positional relationship that is displaced from each other, and the separation wall is formed at this displaced position. Also, the flow of the cathode off-gas is not greatly suppressed, and the pressure loss does not increase.
Therefore, a small-sized gas-liquid separator capable of separating water satisfactorily without greatly restricting the flow of the cathode off-gas from the fuel cell is constructed.

As another configuration, the offset positional relationship is such that the introduction channel and the discharge channel are arranged in a mutually offset relationship to form a stepped portion, and the separation wall is formed at the stepped portion . The stepped portion may be formed by the sloped portion on the upper side and the portion along the vertical direction on the lower side .

According to this, since the introduction channel and the discharge channel are arranged in a mutually offset relationship, a stepped portion is formed, and a separation wall is formed in this stepped portion. is not required. In addition, since the cathode off-gas from the introduction channel is brought into contact with the separation wall formed in the stepped portion to separate the water contained in the cathode off-gas, the flow of the cathode off-gas can be made smooth without strain.

As another configuration, the flow path center of the discharge flow path may be inclined with respect to the flow path center of the introduction flow path.

According to this, when the cathode off-gas flowing in the introduction channel flows into the discharge channel after coming into contact with the separation wall, the cathode off-gas flows in the direction away from the introduction channel. It is possible to improve the gas-liquid separation performance as compared with the case where the center and the channel center of the discharge channel are arranged at the same position.

1 is a diagram showing the configuration of a fuel cell unit; FIG. It is a sectional view of a gas-liquid separator. It is sectional drawing of the gas-liquid separator of another embodiment (a). It is sectional drawing of the gas-liquid separator of another embodiment (b).

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings.
FIG. 1 shows a fuel cell unit FC mounted on a fuel cell vehicle (FCV). The fuel cell unit FC includes an anode-side block FCa (on the left side of the fuel cell 1 in the figure) for supplying hydrogen gas as fuel gas to and from the fuel cell 1, and a cathode-side block FCc for supplying and discharging air containing oxygen gas. (on the right side of the fuel cell 1 in the figure).

The anode-side block FCa includes an anode gas channel 2 and an anode off-gas channel 3 . The cathode-side block FCc includes a cathode gas channel 4 and a cathode off-gas channel 5 .

The anode gas channel 2 of the anode-side block FCa is provided with a tank 7 for storing hydrogen gas, a flow control valve 8 for controlling the supply amount of hydrogen gas, and an ejector 9 . The anode off-gas channel 3 includes a gas-liquid separation unit 10 and a return channel 11 for supplying the hydrogen gas separated by the gas-liquid separation unit 10 to the ejector 9 .

The gas-liquid separation unit 10 has a general configuration described in Patent Document 1 (Japanese Unexamined Patent Application Publication No. 2017-147159) or Patent Document 2 (Japanese Unexamined Patent Application Publication No. 2016-72183). The gas-liquid separation unit 10 is configured so that water separated from the anode off-gas can be discharged by a water discharge control valve 10a, and hydrogen gas separated from the anode off-gas can be discharged by an exhaust gas control valve 10b.

The cathode-side block FCc is provided with a humidifier 13 in a region spanning the cathode gas flow path 4 and the cathode off-gas flow path 5, and is provided with a bypass flow path 4a for sending air without passing through the humidifier 13. . The humidifier 13 is of a temperature-humidity exchange type that takes in moisture and heat from the cathode offgas in the cathode offgas flow path 5 and provides the moisture and heat taken in to the cathode gas in the cathode gas flow path 4 .

The cathode gas channel 4 is provided with an air pump 14 for supplying air, and is a three-way switching valve that can be switched between a state of supplying air to the humidifier 13 and a state of flowing air through the bypass channel 4a. 15.

The cathode offgas channel 5 includes a gas-liquid separator 20 (details of the gas-liquid separator 20 will be described later) for removing water contained in the cathode offgas, and a discharge control valve 16 for controlling discharge of the cathode offgas. ing. It also has a confluence control valve 17 that allows air to flow between the cathode gas flow path 4 and the cathode off-gas flow path 5 .

In this fuel cell unit FC, the flow control valve 8, the drainage control valve 10a, the exhaust gas control valve 10b, the discharge control valve 16, and the confluence control valve 17 are driven by electromagnetic solenoids to open and close. It is configured as a solenoid valve that can set the opening corresponding to the current flowing through the valve. The switching valve 15 is configured to switch the flow path by driving the electric motor, and the air pump 14 is configured to supply air by driving the electric motor.

[Operation of fuel cell]
By configuring the fuel cell unit FC in this way, the hydrogen gas in the tank 7 is supplied from the anode gas flow path 2 to the anode side of the fuel cell 1 by controlling the flow rate control valve 8, and at the same time, the air pump 14 is operated. Power generation in the fuel cell 1 is realized by supplying air from the cathode gas flow path 4 to the cathode side of the fuel cell 1 by driving.

During this power generation, the anode off-gas is discharged to the anode off-gas flow path 3, and the gas-liquid separation unit 10 separates hydrogen and water contained in the anode off-gas. The separated hydrogen is returned to the ejector 9 through the return channel 11 and supplied from the ejector 9 to the anode gas channel 2 . Also, the separated water is temporarily stored inside the separator and discharged to the outside by opening the water discharge control valve 10a.

During power generation, the cathode off-gas is discharged to the cathode off-gas flow path 5, and the air and water contained in the cathode off-gas are separated by the gas-liquid separator 20. FIG. The separated air is exhausted through exhaust control valve 16 . The separated water is temporarily stored inside the separator and discharged by opening the discharge valve 24 .

In the humidifier 13, the cathode off-gas flows inside, so that moisture and heat are taken in from the cathode off-gas and supplied to the cathode gas. As a result, the cathode gas containing moisture and having an increased temperature is supplied from the cathode gas flow path 4 to the cathode side of the fuel cell 1 .

In particular, in the cathode offgas channel 5, since the humidifier 13 is arranged downstream of the gas-liquid separator 20, the gas-liquid separator 20 separates gas and liquid so as to leave a part of the water contained in the cathode offgas. It is desirable to

[Gas-liquid separator]
As shown in FIG. 2, the gas-liquid separator 20 is configured by connecting a discharge pipe 22 and a recovery block 23 to a body block 21 , and the recovery block 23 is provided with a discharge valve 24 . The body block 21, the discharge pipe 22, and the recovery block 23 are made of resin.

The gas-liquid separator 20 introduces the cathode off-gas from the introduction part A of the main block 21, discharges the introduced cathode off-gas from the discharge part B at the projecting end of the discharge pipe 22, and removes the water contained in the cathode off-gas. A collection block 23 serving as a collection section C arranged at the boundary between the introduction section A and the discharge section B collects.

As shown in FIG. 2, the main block 21 includes an introduction channel 21a for receiving the cathode off-gas so as to allow the flow in the horizontal direction X, and an outlet channel 21b for guiding the received cathode off-gas in the oblique upward direction Y. , and a recovery channel 21c for guiding the recovered water in the vertically downward direction Z are formed. Further, inside the discharge pipe 22, a discharge passage 22c is configured to guide the cathode off-gas in the discharge direction Ex.

The arrow indicated as the horizontal direction X in FIG. 2 also indicates the position of the channel center of the introduction channel 21a. Similarly, the discharge direction Ex also indicates the position of the channel center of the discharge channel 22c. As is clear from the figure, the flow path center of the outlet flow path 21b is inclined with respect to the flow path center of the introduction flow path 21a.

The introduction part A for the cathode off gas is arranged at the upstream end position of the introduction flow path 21a of the main block 21 in the introduction direction. As shown in FIG. 2, the inner diameter D of the introduction channel 21a, the inner diameter D of the outlet channel 21b, and the inner diameter D of the recovery channel 21c are set to the same value. As a result, the cross-sectional shapes of the respective flow paths become circular. Furthermore, the inner diameter of the discharge pipe 22 is formed in a circular shape with an inner diameter equal to the inner diameter D of the lead-out flow path 21b. In order to suppress pressure loss when the cathode off-gas passes through the gas-liquid separator 20, the inner diameter of the lead-out channel 21b may be larger than the inner diameter D of the lead-in channel 21a.

A separation wall W is formed by a portion of the upper end portion of the recovery channel 21c that contacts the cathode off-gas flowing along the introduction channel 21a. Since the separation wall W is arranged at a position connected to the recovery channel 21c, it is formed in a shape along the cylindrical inner surface of the recovery channel 21c.

As shown in FIG. 2, the discharge pipe 22 has a shape in which a cylindrical member is curved. The discharge pipe 22 is integrally formed with a base end pipe portion 22a for receiving the cathode off-gas flowing in the oblique upward direction Y and a discharge pipe portion 22b for horizontally sending out the cathode off-gas from the base end pipe portion 22a. there is A discharge passage 22c is formed inside the discharge pipe 22, and a discharge portion B is arranged at the end of the discharge pipe 22 on the discharge side.

The end portion of the base end pipe portion 22a of the discharge pipe 22 is provided with a flange-like portion. , are fixed by technology using bolts.

As shown in FIG. 2, the recovery block 23 has a guide tube portion 23a formed in a posture along the vertical downward direction Z, and a bottom wall portion 23b arranged at a position that closes the lower end of the guide tube portion 23a. At the same time, a filtering unit F is provided at an upper position of the bottom wall portion 23b, and a discharge valve 24 is provided outside the bottom wall portion 23b.

In the collection block 23, a water storage space S is formed by a space surrounded by the lower end portion of the guide tube portion 23a and the bottom wall portion 23b, and the filtration unit F is arranged above the water storage space S. The filtration unit F is composed of a filter 27 made of a mesh material using metal wire or nylon on the inner periphery of an annular frame 26 that is in close contact with the inner periphery of the guide tube portion 23a. function.

A drainage channel 23c is formed in the bottom wall portion 23b in the lateral direction, and a discharge valve 24 is connected to the downstream side of the drainage channel 23c. The discharge valve 24 includes a valve element 24a that opens and closes the drainage flow path 23c, and an electromagnetic solenoid 24b that operates the valve element when energized.

The upper end portion of the guide tube portion 23a is provided with a flange-like portion, and the flange-like portion communicates with the recovery passageway 21c of the main body block 21 using heat welding or bonding techniques or bolts. fixed by technology.

[Gas-liquid separation in gas-liquid separator]
As shown in FIG. 2, the gas-liquid separator 20 is arranged such that the introduction channel 21a and the discharge channel 22c are vertically shifted. Due to such a positional relationship, a stepped portion is formed where the introduction channel 21a and the discharge channel 22c are offset, and a separation wall W is formed at this stepped portion.

The center of the introduction channel 21a (the position shown in the drawing as the horizontal direction X) and the center of the discharge channel 22c (the position shown in the drawing as the discharge direction Ex) are inclined. Therefore, part of the cathode off-gas flowing in the horizontal direction X in the inlet channel 21a contacts the separation wall W, flows in the obliquely upward direction Y, and is further sent out along the discharge direction Ex of the discharge channel 22c. be

That is, when the cathode off-gas containing water in the state of mist or the like comes into contact with the separation wall W, the water contained in the gas adheres to the separation wall W and flows down the surface of the separation wall W. Also, even if the cathode off-gas does not contact the separation wall W, when the flow direction changes to the obliquely upward direction Y, heavy water drops downward due to its own weight.

Water (water droplets) thus separated from the cathode off-gas by the action of the separation wall W falls along the vertically downward direction Z and is stored in the water storage space S at the bottom of the collection block 23 .

In particular, in this configuration, the cathode off-gas is in contact with a single separation wall W. Therefore, compared to, for example, a configuration in which a plurality of wall bodies are contacted or a cathode off-gas that creates a vortex, the structure is improved. It is simple, the cathode off-gas pressure loss is small, and the cathode off-gas can be delivered smoothly.

Also, the water recovered by the recovery block 23 (recovery portion C) is stored in the water storage space S, but is discharged to the outside by the opening operation of the discharge valve 24 . The fuel cell unit FC estimates the amount of water contained in the cathode off-gas based on information such as the current value output from the fuel cell 1, and shortens the interval at which the discharge valve 24 is opened as the estimated amount of water increases. The control mode is set so that

As described above, the gas-liquid separator 20 has a small size and a simple structure, and separates and recovers water well from the cathode off-gas. Moreover, since part of the cathode off-gas is discharged from the discharge part B without coming into contact with the separation wall W, part of the water contained in the cathode off-gas is discharged. As a result, the process of taking in water from the cathode off-gas in the humidifying device 13 and giving it to the cathode gas can be performed without difficulty.

[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. 3, the vertical dimension of the separation wall W is made larger than the inner diameter D of the introduction channel 21a. As a specific example, the upper end position of the separation wall W is determined so as to reach a position higher than the upper end level Lt of the introduction channel 21 a of the main body block 21 .

With this structure, the cathode off-gas introduced from the inlet A is more likely to come into contact with the separation wall W, and the flow direction (angle change) of the cathode off-gas flowing upward is increased to increase the flow direction of the cathode off-gas. Separation performance is improved.

In addition, in the configuration of this alternative embodiment (a) as well, the cross-sectional shape of the introduction channel 21a and the cross-sectional shape of the outlet channel 21b have the same inner diameter D as in the configuration described in FIG. formed in a circular shape. In order to suppress pressure loss when the cathode off-gas passes through the gas-liquid separator 20, the inner diameter of the lead-out channel 21b may be larger than the inner diameter D of the lead-in channel 21a.

(b) As shown in FIG. 4, the posture of the separation wall W is made equal to the direction in which the lead-out flow path 21b is formed (the diagonally upward direction Y). As a specific example, the lower end position of the separation wall W is determined at a position equal to the lower end level Lb of the introduction channel 21a of the main body block 21, and the posture of the separation wall W is determined.

With this configuration, the pressure loss when the cathode off-gas introduced from the inlet A comes into contact with the partition wall W can be reduced, and the cathode off-gas can flow smoothly upward.

In addition, in the configuration of this alternative embodiment (a) as well, the cross-sectional shape of the introduction channel 21a and the cross-sectional shape of the outlet channel 21b have the same inner diameter D as in the configuration described in FIG. formed in a circular shape. In order to suppress pressure loss when the cathode off-gas passes through the gas-liquid separator 20, the inner diameter of the lead-out channel 21b may be larger than the inner diameter D of the lead-in channel 21a.

(c) The separation wall W is formed with a flat surface or a gently curved surface. That is, since the separation wall W described in FIG. 2 as the “embodiment” and the separation wall W of another embodiment (a) are configured by part of the recovery channel 21c, the cylindrical shape of the recovery channel 21c part of the inner surface of the In contrast, in this alternative embodiment (c), by forming the separation wall W with a flat surface or a gently curved surface, the cathode off-gas flowing from the introduction portion A along the horizontal direction X comes into contact with the separation wall W. It is possible to increase the area of the separation wall W, thereby improving the gas-liquid separation performance. Further, in this alternative embodiment (c), when viewed in the horizontal direction X, part of the introduction channel 21a and the outlet channel 21b overlap. Therefore, the pressure loss when the cathode off-gas flows through the gas-liquid separator 20 can be further reduced.

(d) The inner surfaces of the introduction channel 21a and the outlet channel 21b of the main block 21 are formed with small irregularities or rough surfaces to increase the contact area of the cathode off-gas. With this configuration, when the cathode off-gas comes into contact with the water, the water contained in the cathode off-gas can be turned into water droplets, and the water separation performance can be improved.

(e) The discharge direction of the cathode off-gas is set so that the cathode off-gas is sent out horizontally (in a direction parallel to the horizontal direction X) at a position higher than the introduction part A. In this configuration, a stepped portion is formed between the introduction portion A and the discharge portion B, and the separation wall W is formed in this stepped portion, which is a simple configuration. can be high

As a modification of this alternative embodiment (d), the cathode off-gas is supplied in a non-horizontal position, such as by sending the cathode off-gas from obliquely upward to obliquely downward at the introduction portion A. Further, the cathode off-gas is discharged in a non-horizontal direction such as obliquely downward at the discharging portion B.

(f) A separation wall W is configured by providing a dedicated member inside the main block 21 . In other words, in the "embodiment" or "another embodiment", the separation wall W was configured by the inner surface connected to the inner wall of the recovery channel 21c. This not only allows the use of materials suitable for gas-liquid separation, but also allows the angle of the separation wall W to be adjusted.

INDUSTRIAL APPLICABILITY The present invention can be used for a gas-liquid separator that separates a cathode off-gas from a fuel cell.

1 Fuel cell 21a Introductory channel 22c Discharge channel A Introductory part B Discharge part C Recovery part S Water storage space W Separation wall

Claims (3)

an inlet for receiving cathode off-gas discharged from the fuel cell;
a discharge section for discharging cathode off-gas;
a collection unit arranged at a boundary between the introduction unit and the discharge unit for separating and collecting water contained in the cathode off-gas;
a cathode off-gas introduction channel in the introduction part and a cathode off-gas discharge channel in the discharge part are arranged in a positional relationship shifted from each other so that the discharge channel is higher than the introduction channel ,
A separation wall that separates water by coming into contact with the cathode off-gas from the introduction channel at this offset position has a sloping portion that sends out the cathode off-gas obliquely upward. A gas-liquid separator in which the water storage space of the collecting section is arranged. As the offset positional relationship, a stepped portion is formed by arranging the introduction channel and the discharge channel in a mutually staggered relationship, and the separation wall is formed at the stepped portion ,
2. The gas-liquid separator according to claim 1, wherein said stepped portion is formed by said sloped portion on the upper side and a portion along the vertical direction on the lower side . 2. The gas-liquid separator according to claim 1, wherein the center of said discharge channel is inclined with respect to the center of said introduction channel.

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