JP2005011641A - Exhaust gas treatment device of fuel cell - Google Patents

Abstract

The present invention provides an exhaust gas treatment device for a fuel cell, in which high-concentration hydrogen is not likely to be released to the outside without having a dilution container having a high sealing property.
A diluting vessel 6 has a double structure, a hydrogen chamber 15 for storing hydrogen gas introduced into the diluting vessel 6 is provided, and passage chambers 16a to 16c through which a cathode off gas flows are provided outside the hydrogen chamber 15. Provide. Then, on the inlet side and the outlet side of the hydrogen chamber 15, conduction ports 22 a and 22 b respectively connected to the cathode off gas passage chamber are provided.
[Selection] Figure 4

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an exhaust gas processing apparatus for a fuel cell, and more particularly to an exhaust gas processing apparatus for a fuel cell that performs hydrogen gas processing at the time of purging in an exhaust line of a fuel cell power generation system.
[0002]
[Prior art]
In a fuel cell power generation system such as an electric vehicle, for example, when pure hydrogen (hereinafter referred to as “hydrogen”) is used as a fuel, the supply of hydrogen to the fuel cell is to improve the fuel efficiency and increase the utilization efficiency. A circulation system is adopted for the anode piping system. As this circulation system, an ejector that sucks hydrogen by generating a negative pressure, a vacuum pump, or the like is used. If the circulation of hydrogen in such a circulation system is continued for a long time, the concentration of impurities, for example, nitrogen in hydrogen increases, and the concentration of hydrogen decreases accordingly, which may reduce the efficiency of power generation. Therefore, a purge operation for discharging impurities such as nitrogen and water is necessary. However, since the anode piping system is filled with hydrogen, if high-concentration hydrogen is also discharged to the outside during this purge operation, the hydrogen concentration is high even if impurities are contained, There are many inconveniences when high concentration hydrogen is discharged into the atmosphere. In addition, water may accumulate in the circulation system, which may deteriorate the flow of hydrogen in the anode piping system of the fuel cell system. Therefore, a gas-liquid separator is provided in the circulation system of the fuel cell to remove moisture, and the hydrogen offgas discharged from this circulation system is retained in the diluter that is a diluting device and mixed with oxygen offgas (air). Then, after diluting the hydrogen concentration, they are further merged downstream of the muffler and discharged to the atmosphere (see, for example, Patent Document 1).
[0003]
[Patent Document 1]
JP 2002-289237 A (pages 12-13, FIGS. 7-8)
[0004]
[Problems to be solved by the invention]
As described in Patent Document 1, a diluting device used in a hydrogen gas discharge line is an indispensable device for safely releasing hydrogen released during draining or purging of an anode system to the outside of the vehicle.
The present applicant has proposed an exhaust fuel diluter having a structure in which a diluter and a muffler are integrated as a structure obtained by further improving the diluter described in Patent Document 1 (for example, a patent application). 2002-288890). In the earlier application, as shown in FIG. 5, the exhaust fuel diluter (6) includes an inlet portion (8) for introducing hydrogen gas purged from the fuel cell, and hydrogen introduced from the inlet portion (8). It comprises a residence chamber (18) for retaining gas and a cathode pipe (14) provided through the residence chamber (18). The cathode pipe (14) is formed in a hole (21) in the middle of the pipe. In addition, the cathode exhaust gas (air) of the fuel cell is supplied, the hydrogen gas in the retention chamber (18) is sucked into the cathode pipe (14) from the hole (21), and the hydrogen gas is discharged from the fuel cell. The mixture is diluted with the cathode exhaust gas (air) to be diluted and then discharged to the atmosphere.
[0005]
However, in the exhaust fuel diluter according to this prior application, high concentration hydrogen always exists in the seal portion where the hydrogen gas inlet port (8) is connected to the diluter box. Therefore, in order to prevent hydrogen from leaking to the outside, a structure having a high sealing property such as an all-around welding structure or a seal structure in which an O-ring is provided is required, and there is a problem that the structure is expensive or complicated. there were.
[0006]
Therefore, the present invention satisfies the function as a dilution vessel, and high-concentration hydrogen can be discharged to the outside even if it does not have a high sealing performance such as an all-around welding structure or a sealing structure in which an O-ring is provided. It is an object of the present invention to provide an exhaust gas treatment device for a fuel cell that is not likely to be released.
[0007]
[Means for Solving the Problems]
The invention according to claim 1 of the present invention that solves the above-mentioned problems is a dilution container that mixes and dilutes the hydrogen gas purged from the fuel cell with the cathode off-gas discharged from the fuel cell and discharges it to the atmosphere. In the exhaust gas treatment apparatus for a fuel cell provided, the diluting vessel has a double structure, a hydrogen chamber for storing the introduced hydrogen gas is provided inside the diluting vessel, and a passage chamber in which the cathode off gas flows outside the hydrogen chamber And a conduction port connected to the cathode off-gas passage chamber is provided on the inlet side and the outlet side of the hydrogen chamber, respectively.
[0008]
According to the first aspect of the present invention, the double-structured hydrogen leakage prevention structure in which the hydrogen chamber is disposed inside the dilution container is configured such that the cathode off gas used for dilution flows outside the hydrogen chamber. As a result, the outside of the hydrogen chamber is completely covered with the cathode off-gas. Therefore, even if the introduction part that introduces the hydrogen gas into the hydrogen chamber arranged inside the dilution container is damaged, the cathode Since it is enclosed with off-gas, it can be set as the leak prevention structure which does not have a possibility that high concentration hydrogen gas may leak outside directly. In addition, this double structure can enhance the silencing effect during the hydrogen purge while improving the measures against hydrogen leakage.
[0009]
A second aspect of the present invention is the exhaust gas treatment apparatus for a fuel cell according to the first aspect, characterized in that a pressure loss partition plate for partitioning the inlet side and the outlet side of the passage chamber is provided.
Here, the pressure-loss partition plate refers to a partition plate provided with a predetermined opening so as to give resistance to the flow of the cathode off gas in the dilution container and simultaneously reduce the pressure of the cathode off gas.
[0010]
According to the second aspect of the present invention, in order to satisfy the dilutability, a pressure loss partition plate that causes a pressure loss in the cathode off gas is provided in the passage chamber in which the cathode off gas used for dilution flows, and the inlet side of the passage chamber. Prevent leakage of hydrogen by placing it between the outlet side and a conduction port for the diluted fluid to go to the hydrogen chamber in the upstream part, and a conduction port for the hydrogen from the hydrogen chamber to mix with the diluted fluid in the downstream part The structure. Since the flow of the cathode off gas flowing through the passage chamber outside the hydrogen chamber is given resistance by the pressure loss partition plate, the induction of the cathode off gas into the hydrogen chamber is easily promoted. As a result, hydrogen leakage can be prevented and mixing of purge hydrogen and cathode off gas in the hydrogen chamber is promoted, so that effective dilution can be performed. In addition, the double structure partitioned by the pressure loss partition plate of the dilution container can improve the silencing effect at the time of hydrogen purge while improving measures against hydrogen leakage.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, with reference to the drawings, details of an exhaust gas treatment apparatus for a fuel cell according to an embodiment of the present invention will be described. In the drawings to be referred to, FIG. 1 is a plan view showing a fuel cell electric vehicle equipped with an exhaust gas treatment device for a fuel cell according to an embodiment of the present invention, and FIG. 2 is a fuel cell having the exhaust gas treatment device for a fuel cell. It is explanatory drawing which shows a system. FIG. 3 is a schematic explanatory diagram showing the flow of cathode offgas and purge hydrogen in the dilution vessel. 4 is an explanatory view showing the structure of each part of the dilution container shown in FIG. 3 in a perspective view. 3 and 4 only schematically show the components in order to express the flow of the cathode off gas and purge hydrogen, and the positional relationship between the components is not limited to this. In particular, in FIG. 3, the connection structure of the purge hydrogen pipe 8 and the drain pipes 10 and 11 to the hydrogen chamber 15 is joined to the purge hydrogen pipe 8 as shown in FIG. 2 so as to penetrate the cathode off-gas passage chamber 16a. Alternatively, in a form not shown, the passage chamber 16a may be penetrated and connected without being joined to the purge hydrogen pipe 8 as a separate pipe. Moreover, the arrow in a figure has shown the flow of gas.
[0012]
As shown in FIG. 1, a fuel cell system box 2 is disposed under a floor at a substantially central portion of a fuel cell electric vehicle (hereinafter referred to as “vehicle”) 1. Inside the fuel cell system box 2, a fuel cell system, that is, a temperature controller 3, a fuel cell stack 4, a humidifier 5, and a dilution container 6 are arranged in order from the front to the rear of the vehicle 1. . The fuel cell system includes, in addition to the devices 3 to 6, a radiator (not shown) that cools the fuel cell stack 4, a high-pressure hydrogen container 27 shown in FIG. 2, a compressor 25 that can adjust the amount of discharged air, and the like. Has been.
[0013]
The fuel cell stack 4 is supplied with hydrogen as fuel stored in the high-pressure hydrogen container 27 and air taken from the outside of the vehicle by the compressor 25 to generate electricity and supply electricity for driving the vehicle 1. In order to operate the fuel cell stack 4 suitably, the temperature controller 3 adjusts the temperature of hydrogen and air supplied to the fuel cell stack 4, and the humidifier 5 supplies hydrogen and air supplied to the fuel cell stack 4. Humidify. The dilution container 6 discharges and purges purge hydrogen from the anode piping system into the dilution container 6, mixes it with the cathode off-gas (exhaust air), dilutes it, and then discharges it outside the vehicle.
[0014]
As shown in FIG. 2, the fuel cell stack 4 is formed by an electrochemical reaction between hydrogen serving as fuel stored in the high-pressure hydrogen container 27 and air supplied from the compressor 25 (hereinafter referred to as “supply air”). It generates electricity. Further, an anode drain pipe 10 for discharging a drain of water or the like generated with power generation to the dilution container 6 is connected to the lower part of the fuel cell stack 4. The water generated in the fuel cell stack 4 flows into the discharge fuel dilution container 6 by manually or automatically opening and closing the on-off valve 12 provided at an appropriate position of the anode drain pipe 10. Yes.
[0015]
On the anode side of the fuel cell stack 4, a hydrogen supply pipe 28 that leads hydrogen from the high-pressure hydrogen container 27 to the inlet is connected via the humidifier 5, and hydrogen is returned to the fuel cell stack 4 at the outlet again. A circulation pipe (circulation system) 7 is connected. The circulation pipe 7 is configured to return the hydrogen once used in the fuel cell stack 4 to the upstream side of the humidifier 5 through the circulation pipe 7 in order to improve the fuel efficiency and increase the utilization efficiency. . Further, the circulation pipe 7 is branched by a purge hydrogen pipe 8 for discharging hydrogen containing impurities contained in hydrogen and water generated in the fuel cell stack 4 to the dilution container 6. Connected. The hydrogen in the circulation pipe 7 is opened and closed at a predetermined interval by a purge valve 9 provided at an appropriate position of the purge hydrogen pipe 8 by a signal from a control device (not shown), so that the dilution container 6 The hydrogen chamber 15 is purged (discharged) intermittently.
[0016]
On the cathode side of the fuel cell stack 4, an air supply pipe 26 that guides the supply air from the compressor 25 is connected to the inlet, and the air discharged from the fuel cell stack 4 at the outlet (hereinafter referred to as “cathode off gas”). ) Is connected to the outside. The downstream side of the cathode offgas pipe 14 is connected to the dilution container 6. The cathode off gas is discharged outside after diluting purge hydrogen to an appropriate hydrogen concentration as described later in a dilution vessel 6 provided at a proper position of the cathode off gas pipe 14.
[0017]
The humidifier 5 is provided at an appropriate position of the hydrogen supply pipe 28, and a humidifier drain pipe 11 for discharging a drain of water or the like to the dilution container 6 through the purge hydrogen pipe 8 is connected to the lower portion thereof. The drain in the humidifier 5 flows into the dilution container 6 by manually opening or closing the on-off valve 13 provided at an appropriate position of the humidifier drain pipe 11. Further, although not shown, the air supply pipe 26 is similarly provided with a humidifier, a humidifier drain pipe, and an open / close valve, and the drain of the humidifier is discharged to the dilution container 6. In FIG. 2, the anode drain pipe 10 and the humidifier drain pipe 11 are connected downstream of the purge hydrogen pipe 8 as described above, and are connected to the hydrogen chamber 15 in the dilution container 6 through the purge hydrogen pipe 8. Although the embodiment is shown, the anode drain pipe 10 and the humidifier drain pipe 11 may be individually connected to the hydrogen chamber 15 of the dilution container 6.
[0018]
The dilution container 6 is a container having a hydrogen chamber 15 disposed inside thereof and passage chambers 16 a to 16 c disposed around the hydrogen chamber 15. The hydrogen chamber 15 is a chamber in which hydrogen purged intermittently mainly from the circulation pipe 7 is temporarily stored and retained, and the passage chambers 16a to 16c are used for diluting hydrogen gas from the cathode offgas pipe 14. This is a chamber into which the cathode offgas from the fuel cell stack 4 flows and forms a passage whose volume is larger than that of the cathode offgas pipe 14.
[0019]
The passage chambers 16a to 16c are arranged in the order of the passage chambers 16a, 16b, and 16c from the upstream side of the cathode off gas. The dilution container 6 is provided with pressure loss partition plates 17a and 17b that divide the passage chambers. The purge hydrogen diluted to an appropriate hydrogen concentration in the dilution container 6 is discharged to the atmosphere. The dilution container 6 may be formed as a double-structure container having at least one hydrogen chamber and two passage chambers arranged before and after the pressure loss partition plate.
[0020]
Next, with reference to FIG. 3 and FIG. 4, the structure of the dilution container 6 of this Embodiment is demonstrated. In the illustrated embodiment, the dilution container 6 is a double-structured dilution container in which a hydrogen chamber 15 is disposed inside the dilution container 6. In the figure, black thin line arrows indicate the flow of purge hydrogen gas, and white arrows indicate the flow of cathode off gas. A hatched arrow indicates the flow of purge hydrogen after dilution.
The hydrogen chamber 15 is supported by being fitted into the center part of the pressure loss partition plates 17a and 17b. By fixing the outer edges of the pressure loss partition plates 17a and 17b to the inner peripheral wall of the dilution container 6, the hydrogen chamber 15 It is configured to be held in the inner space. That is, the pressure loss partition plate 17a and the pressure loss partition plate 17b are respectively disposed at both ends around the hydrogen chamber 15, and the hydrogen chamber 15 is held in the inner space of the dilution container 6 by the pressure loss partition plates 17a and 17b. Yes. Therefore, the pressure loss partition plates 17a and 17b have a spacer function for spatially holding the hydrogen chamber 15 inside the dilution container 6.
[0021]
The space formed between the dilution container 6 and the hydrogen chamber 15 is partitioned into three spaces by the pressure loss partition plates 17a and 17b, thereby forming passage chambers 16a, 16b and 16c. The upstream end of the hydrogen chamber 15 is provided with a plurality of inlet-side conduction ports 22a for introducing a part of the cathode off gas, and diluted hydrogen is provided at the downstream end of the hydrogen chamber 15. A plurality of outlet-side conduction ports 22b for discharging gas are provided. The pressure-loss partition plates 17a and 17b are disposed apart from each other between the inlet-side conduction port 22a and the outlet-side conduction port 22b. The inlet-side conduction port 22a and the outlet-side conduction port 22b are provided on the circumferential surface or side surface of the hydrogen chamber 15 parallel to the direction in which the cathode off-gas flows from the inlet side to the discharge side in the space in the dilution container 6.
[0022]
The pressure-loss partition plates 17a and 17b are formed from a perforated plate or a punching plate. The pressure loss partition plate 17a has a plurality of hole groups or mesh holes 22c, and the pressure loss partition plate 17b has a plurality of hole groups or mesh holes 22d and a drain hole 22f. These hole groups or mesh holes 22c and 22d are provided to give passage resistance to the cathode off gas. A plurality of hole groups or mesh holes 22 c and 22 d provided in the pressure loss partition plates 17 a and 17 b are formed intermittently or continuously along the outer periphery of the hydrogen chamber 15. In addition, you may use the pressure loss partition plate 17a in which the through-hole 22f for draining was formed.
[0023]
The cathode offgas piping 14 is connected to the front wall 18 of the dilution container 6, and the cathode offgas is introduced from the inlet portion 20 into the passage chamber 16 a disposed upstream. The cathode off-gas introduced into the passage chamber 16a is diffused in the passage chamber 16a, and is further subjected to squeezing resistance by the plurality of hole groups of the pressure-loss partition plates 17a and 17b or the mesh holes 22c and 22d, causing pressure loss. It moves to the downstream side sequentially to 16b, 16c and flows through the passage chamber.
[0024]
On the other hand, a purge hydrogen pipe 8 is connected to the front wall 15a of the hydrogen chamber 15 through the passage chamber 16a disposed on the upstream side, and purge hydrogen is introduced into the hydrogen chamber 15 from the introduction portion 21a. The purge hydrogen introduced into the hydrogen chamber 15 is diffused in the hydrogen chamber 15 and temporarily stays there. At this time, the water condensed due to staying in the hydrogen chamber 15 and the drain discharged from the humidifier are discharged from the drain hole 22e provided in the bottom surface of the hydrogen chamber 15 to the bottom of the passage chamber 16b. ing.
[0025]
Further, the front wall 18 of the dilution container 6 and the front wall 15a of the hydrogen chamber 15 are spaced apart from each other, and the rear wall 19 of the dilution container 6 and the rear wall 15b of the hydrogen chamber 15 are also spaced apart from each other. Are arranged. As a result, with the structure in which the pressure loss partition plates 17a and 17b are arranged, the hydrogen chamber 15 is held in the space of the dilution container 6, and the cathode offgas flows in the space formed by the dilution container 6 and the hydrogen chamber 15. The passage chambers 16a, 16b, and 16c are sequentially formed along the same.
[0026]
A part of the cathode off-gas whose flow path is restricted by the plurality of hole groups of the pressure loss partition plate 17a or the mesh hole 22c of the punching plate enters the hydrogen chamber 15 from the passage chamber 16a through the inlet-side conduction port 22a. The purge hydrogen gas diluted in the hydrogen chamber 15 is discharged from the outlet side conduction port 22b to the passage chamber 16c, and the remaining cathode off-gas passes through the passage chamber 16b from the plurality of hole groups or the mesh holes 22c of the pressure loss partition plate 17a. Then, it further flows to the passage chamber 16c through the plurality of hole groups or the mesh holes 22d of the pressure loss partition plate 17b.
[0027]
In this downstream third stage passage chamber 16c, the purge hydrogen gas exiting the hydrogen chamber 15 merges with the cathode off gas, and is further mixed and diluted in the passage chamber 16c, and is discharged from the discharge pipe 24 through the discharge portion 23. Is released. The aperture ratios of the plurality of hole groups or mesh holes 22c and 22d and the punching plate mesh are optimum models based on a mixture ratio model map created in consideration of the cathode offgas passage flow rate and passage chamber volume. Is selected by design.
Further, the water accumulated in the hydrogen chamber 15 is preferably a drain hole 22e provided on the lower surface of the hydrogen chamber 15 (a drain hole having a diameter of 4 mm or more so as not to affect the dilution performance). ) In a water droplet state, passes through a through hole 22f provided in the lower end portion of the pressure loss partition plate 17b, and further passes through a discharge portion 23 (see FIG. 4) of the dilution container 6 together with the water in the diluted fluid. It is discharged from 24 to the outside.
[0028]
A backfire prevention filter (not shown) may be disposed in the discharge portion 23 of the dilution container 6. By disposing the backfire prevention filter, it is possible to prevent inconvenience and trouble due to backfire from the outside.
[0029]
Next, a method of diluting purge hydrogen with the dilution container 6 will be described. The purge hydrogen is diluted by introducing high-concentration purge hydrogen containing impurities from the purge hydrogen pipe 8 or the like into the hydrogen chamber 15, and a part of the cathode off-gas introduced into the passage chamber 16a by the compressor 25 is replaced with the pressure drop partition plate 17a. With this arrangement, the gas is introduced into the inlet side conduction port 22a, introduced into the hydrogen chamber 15, and mixed and diluted with purge hydrogen.
[0030]
A cathode offgas pipe 14 into which a cathode offgas of exhaust air is introduced is connected to an inlet portion provided on the front wall 18 of the dilution container 6. Cathode off-gas is introduced into the passage chamber 16a from this inlet. Since the passage chamber 16a has a larger volume than the cathode offgas pipe 14, the introduced cathode offgas is expanded and expanded in the passage chamber 16a, so that the pressure energy is reduced and exhausted to the atmosphere. The exhaust noise at the time can be suppressed.
[0031]
On the other hand, the purge hydrogen introduced into the dilution vessel 6 passes through the passage chamber 16a through which the cathode off-gas is disposed on the upstream side of the dilution vessel 6 via the purge hydrogen pipe 8 and flows to the hydrogen chamber 15. be introduced. The purge hydrogen released into the hydrogen chamber 15 through the purge hydrogen pipe 8 stays for a while as the volume increases, and is diffused into the hydrogen chamber 15.
[0032]
After that, due to the pressure loss effect by the pressure loss partition plate 17a, a part of the cathode offgas introduced from the cathode offgas pipe 14 and flowing through the passage chamber 16a is transferred into the hydrogen chamber 15 through the inlet side conduction port 22a of the hydrogen chamber 15. Enter and dilute purge hydrogen. The diluted purge hydrogen is sucked into the cathode off gas flowing through the passage chamber 16c from the outlet side conduction port 22b of the hydrogen chamber 15, and further mixed with the cathode off gas in the passage chamber 16c to be diluted to a low concentration. Discharged outside the vehicle. In addition, the condensed water in the cathode off-gas emitted from the humidifier 5 and the fuel cell stack 4 is also discharged together with the exhaust air.
[0033]
A method of diluting a high concentration of hydrogen containing impurities or the like to an appropriate hydrogen concentration in the hydrogen chamber 15 is performed by using a control device (not shown). Specifically, based on the detection result of the hydrogen concentration detector installed on the discharge side of the dilution container 6, the rotational speed of the compressor 25 is controlled and the purge valve 9 of the purge hydrogen pipe 8 and the cathode offgas pipe 14 are arranged at appropriate positions. This is performed by controlling the opening degree of the provided flow regulating valve (see FIG. 2).
[0034]
As described above, the following effects can be obtained in the present embodiment. A double structure in which the hydrogen chamber 15 is disposed inside the dilution container 6 is configured so that the cathode off gas used for dilution always flows outside the hydrogen chamber 15. As a result, the connection portion of the purge hydrogen introduction portion 21a in the hydrogen chamber 15 and the periphery of the hydrogen chamber 15 are completely covered with the cathode off gas. Even if there is a problem that the introduced purge hydrogen gas leaks from the hydrogen chamber 15 due to damage to the surroundings, the hydrogen chamber 15 is surrounded by the cathode off-gas, so that high-concentration hydrogen gas is directly discharged to the outside. There is no risk of leakage, and a leakage prevention structure that eliminates the disadvantages caused by hydrogen leakage can be obtained. In addition, since the purge structure absorbs the purge noise in the passage chamber around the hydrogen chamber 15 by adopting this double structure, the noise reduction effect at the time of hydrogen purge and the cathode off-gas exhaust are improved while improving the measures against hydrogen leakage. The silencing effect can be enhanced.
[0035]
In addition, the flow of the cathode off gas provided outside the hydrogen chamber 15 is given resistance by the pressure loss partition plate 17a, and the induction of the cathode off gas into the hydrogen chamber 15 is easily promoted. This prevents hydrogen leakage and promotes mixing of purge hydrogen and cathode offgas in the hydrogen chamber 15 to achieve effective dilution. In addition, the double structure partitioned by the pressure drop partition plates 17a and 17b of the dilution container 6 improves the countermeasure against hydrogen leakage and absorbs the purge sound in the passage chamber around the hydrogen chamber 15. It is possible to enhance the noise reduction effect when the cathode off gas is exhausted.
[0036]
(Modification of dilution container)
As an application example in which a normal partition is used instead of the pressure-loss partition plate in the embodiment of the present invention, the following modification can be considered.
[Modification 1] In an exhaust gas treatment apparatus for a fuel cell, provided with a dilution container for mixing and diluting the hydrogen gas purged from the fuel cell with the cathode off-gas discharged from the fuel cell and discharging it to the atmosphere, the dilution container Has a partition chamber structure having a partition between a hydrogen chamber for storing the introduced hydrogen gas and a passage chamber through which the cathode off-gas flows. The passage chamber is disposed at least upstream of the hydrogen chamber and passes through the passage chamber. The hydrogen gas inlet pipe is connected to the hydrogen chamber, and a plurality of conduction ports for introducing the cathode off-gas are provided in the partition, and a structure for preventing hydrogen leakage from the dilution container having a discharge port on the downstream side of the hydrogen chamber is provided. Features.
[0037]
According to the configuration of the first modification, the purge hydrogen introduced into the dilution vessel passes through the passage chamber through which the cathode off-gas disposed on the inlet side upstream of the dilution vessel flows via the purge hydrogen pipe, It is introduced into the hydrogen chamber partitioned by The connection portion of the purge hydrogen pipe serving as the purge hydrogen introduction portion in this partition is surrounded by the cathode off gas in the passage chamber. For this reason, even if this purge hydrogen introduction part does not have a structure with high sealing performance, even if this introduction part is damaged, a high-concentration hydrogen gas does not leak directly to the outside. It can be. In addition, this partition chamber structure can improve the silencing effect at the time of hydrogen purge and the silencing effect at the time of exhausting the cathode off gas while improving the countermeasure against hydrogen leakage.
[0038]
[Modification 2] In the exhaust gas treatment device for a fuel cell according to Modification 1, the dilution chamber is provided with two partitions, and the passage chambers are arranged upstream and downstream of the hydrogen chamber. It features a hydrogen leakage prevention structure for the container.
[0039]
According to the configuration of the second modification, after the cathode off gas is introduced into the hydrogen chamber from the upstream passage chamber through the conduction port and mixed with purge hydrogen to be diluted, the diluted hydrogen gas is supplied to the downstream passage chamber. It is sent out through the conduction port, once retained in this passage chamber, and then discharged to the atmosphere. As a result, since the two partitions are arranged in the dilution container and the chamber is formed in three stages, it is possible to provide a reliable structure for preventing hydrogen leakage from the purge hydrogen introduction portion, as well as purge hydrogen purge noise and cathode off gas. The sound during evacuation can be sufficiently silenced in the dilution container.
[0040]
[Modification 3] In the exhaust gas treatment apparatus for a fuel cell, provided with a dilution container for mixing and diluting the hydrogen gas purged from the fuel cell with the cathode off-gas discharged from the fuel cell and discharging it to the atmosphere, the dilution container Has a partition chamber structure having a partition between a hydrogen chamber for storing the introduced hydrogen gas and a passage chamber for introducing the cathode off-gas, and the hydrogen chamber is disposed on the bottom surface of the dilution container, and upstream of the hydrogen chamber. The side front surface, the rear surface, and the upper surface are partitioned by a partition, and the passage cross-sectional area of the passage chamber provided on the upper surface of the hydrogen chamber is larger than the passage cross-sectional area of the upstream or downstream passage chamber provided on the front or rear surface of the hydrogen chamber A passage chamber having a small passage cross-sectional area, passing through the upstream passage chamber, connecting the hydrogen gas introduction pipe to the hydrogen chamber, and connecting a cathode offgas pipe to the upstream passage chamber, Provided with a plurality of conducting port for introducing the cathode off-gas in the partition surface, and wherein the hydrogen leakage preventing structure of the dilution vessel provided with a discharge port on the downstream side of the dilution container.
[0041]
According to the configuration of the third modification, the hydrogen chamber has a structure common to the bottom surface of the dilution container, and the hydrogen chamber is covered with the cathode offgas introduced into the passage chamber of the dilution container. In addition to providing a structure for preventing leakage of hydrogen, the partitioning chamber structure of the dilution container with respect to the hydrogen chamber can enhance the silencing effect on the purge sound of hydrogen gas and the exhaust sound of cathode off gas. In addition, since the hydrogen chamber is arranged on the bottom surface of the dilution container, there is an advantage that the center of gravity of the dilution container is stable and fits. In this case, if the conduction port provided in the front surface of the hydrogen chamber is disposed at a position facing the flow of the cathode off gas to be introduced, the dilution effect can be enhanced, which is excellent.
[0042]
As mentioned above, this invention is implemented in various aspects, without being limited to the said embodiment and modification.
In the present embodiment and the modification, the dilution container 6 may be a box-shaped container such as a box shape, a cylindrical shape, or an elliptic cylinder shape, and does not particularly specify the shape of the dilution container. Further, although the cathode off gas of the fuel cell is used as the exhaust air, the present invention is not limited to this, and air supplied from the compressor may be used.
[0043]
【The invention's effect】
According to the first aspect of the present invention, since the outer side of the hydrogen chamber is completely covered with the cathode off gas, in the unlikely event, the introduction portion for introducing the hydrogen gas into the hydrogen chamber disposed inside the dilution container Even if it is damaged, since it is enveloped by the cathode off-gas, it is possible to provide a leak-proof preventing structure in which high-concentration hydrogen gas does not leak directly to the outside. Further, this double structure improves the countermeasure against hydrogen leakage and absorbs the purge sound in the passage chamber around the hydrogen chamber, so that the silencing effect at the time of hydrogen purge can be enhanced.
[0044]
According to the second aspect of the present invention, since the flow of the cathode off gas flowing through the passage chamber outside the hydrogen chamber is given resistance by the pressure loss partition plate, the induction of the cathode off gas into the hydrogen chamber is easily promoted. As a result, hydrogen leakage can be prevented and mixing of purge hydrogen and cathode off gas in the hydrogen chamber is promoted, so that effective dilution can be performed. In addition, the double structure partitioned by the pressure loss partition plate of the dilution container improves the noise reduction effect during the hydrogen purge because the purge sound is absorbed in the passage chamber around the hydrogen chamber while improving the countermeasure against hydrogen leakage. be able to.
[Brief description of the drawings]
FIG. 1 is a plan view showing a fuel cell electric vehicle equipped with an exhaust gas treatment device for a fuel cell according to the present invention.
FIG. 2 is an explanatory view showing a fuel cell system having an exhaust gas treatment device for a fuel cell.
FIG. 3 is a schematic explanatory diagram showing the flow of cathode offgas and purge hydrogen in the dilution vessel.
4 is an explanatory view showing the structure of each part of the dilution container shown in FIG. 3 in a perspective view. FIG.
FIG. 5 is an explanatory view of a prior art exhaust fuel diluter.
[Explanation of symbols]
4 Fuel cell stack
6 Dilution container
8 Purge hydrogen piping
14 Cathode off-gas piping
15 Hydrogen chamber
16a passage room
16b passage room
16c passage room
22a Entrance side conduction port
22b Outlet side conduction port

Claims (2)

In a fuel cell exhaust gas treatment apparatus provided with a dilution container that mixes, dilutes and discharges hydrogen gas purged from the fuel cell with cathode off-gas discharged from the fuel cell to the atmosphere,
The dilution container has a double structure,
A hydrogen chamber for storing the introduced hydrogen gas is provided inside the dilution container, and a passage chamber through which the cathode off gas flows is provided outside the hydrogen chamber,
An exhaust gas treatment apparatus for a fuel cell, characterized in that a conduction port connected to a cathode offgas passage chamber is provided on each of an inlet side and an outlet side of a hydrogen chamber. 2. The fuel cell exhaust gas processing apparatus according to claim 1, further comprising a pressure loss partition plate that partitions the inlet side and the outlet side of the passage chamber.

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