JP5266887B2 - Fuel cell exhaust gas dilution device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell unloading gas diluter capable of performing the proper dilution of hydrogen gas by oxidized offgas by the proper mixing of fuel offgas and oxidized offgas. <P>SOLUTION: An auxiliary dilution envelope 13 is prepared in the lower part of a dilution envelope 12 of the unloading gas diluter 11, and the fuel offgas lead-in pipe 16 is connected to a bottom plate 13a of the auxiliary dilution envelope 13. A fuel offgas branch-out pipe 21 is connected to a partition board 13c of the auxiliary dilution envelope 13, and branch-out nozzles 22 are connected to the fuel offgas branch-out pipe 21. An oxidized offgas lead-in pipe 17 and the unloading pipe 18 are connected to the diluting envelope 12. The fuel offgas led to an accumulator chamber 14 of the auxiliary dilution envelope 13 is branched out by the fuel offgas branch-out pipe 21 and the branch-out nozzle 22 and supplied to a branch-out passage 23a of each rectifying tube 23. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to an exhaust gas dilution device for a fuel cell, and more specifically, the hydrogen gas contained in the fuel off-gas discharged from the fuel cell is efficiently diluted with the oxidizing off-gas discharged from the fuel cell and discharged to the atmosphere. The present invention relates to an exhaust gas dilution device for a fuel cell.

Since fuel cells have high power generation efficiency and are friendly to the environment, for example, they are expected as fuel cell vehicles that can replace automobiles having internal combustion engines, and are being developed for practical use.
In a fuel cell system, electric power is generated by reacting hydrogen gas and oxygen gas contained in air by a fuel cell including a fuel electrode to which hydrogen gas is supplied and an oxidant electrode to which oxygen gas in the air is supplied. It is like that. Since the gas discharged from the fuel electrode side of the fuel cell includes unreacted hydrogen gas, in order to effectively use this hydrogen gas, hydrogen gas is circulated from the fuel electrode side outlet to the fuel electrode inlet side. Gas circulation means is provided. A gas-liquid separator constructed by accommodating a hydrogen separation membrane inside the separation vessel is connected to the gas circulation pipe of the gas circulation means. The hydrogen separation membrane of the gas-liquid separator separates hydrogen gas from other gases such as nitrogen gas other than hydrogen gas and permeated water generated during power generation, and returns the hydrogen gas to the fuel cell. Gas and osmotic water are regularly discharged outside. Furthermore, since it is difficult to completely separate and collect hydrogen gas by the gas-liquid separator, the fuel off-gas discharged from the gas-liquid separator is guided to a diluter. Further, the oxidizing off gas discharged from the outlet on the oxidant electrode side of the fuel cell and the generated water generated during power generation are guided to the diluter. Then, the fuel off-gas and the oxidizing off-gas are mixed in the diluter to dilute the hydrogen gas concentration to a safe reference value or less and release it into the atmosphere.

  In order to dilute the hydrogen gas, a fuel cell exhaust gas diluting device described in Patent Document 1 has been proposed. This dilution apparatus is configured as shown in FIGS. As shown in FIG. 8, an anode (fuel electrode) side exhaust pipe 42 for introducing fuel off-gas is connected to the left side wall portion of the rectangular box-shaped container 41 shown in the figure, and oxidizing off-gas is introduced into the container 41. An upstream exhaust pipe 43 on the cathode (oxidant electrode) side is inserted. A downstream exhaust pipe 44 is connected to the right side wall portion of the container 41 in correspondence with the upstream exhaust pipe 43. Two shielding plates for meandering the fuel off-gas introduced by the anode side exhaust pipe 42 into the gap 41 between the upstream side exhaust pipe 43 and the downstream side exhaust pipe 44 inside the container 41. 45 and 46 are attached. The shield plates 45 and 46 form a meandering passage for the fuel gas to increase the residence time of the hydrogen gas and improve the dilution function.

  The diluting device described above has a problem that the hydrogen gas cannot be sufficiently diluted because the air in the corners in the container 41 indicated by a two-dot chain line in FIG. 9 cannot be sufficiently utilized for diluting the hydrogen gas. Further, since the fuel off gas flows through the meandering passage, there is a problem that the pressure loss is increased.

On the other hand, as an exhaust gas treatment device for a fuel cell, a device disclosed in Patent Document 2 has been proposed. As shown in FIG. 10, the exhaust gas treatment apparatus has a fuel off gas introduction pipe 52 connected to the right side wall of the fuel diluter 51 and a oxidization off gas introduction pipe 53 connected to the right side of the bottom wall. The diluted gas discharge pipe 54 is connected to the left side of the bottom wall in the figure. Further, a plurality of flat plates 55 are provided in parallel with each other in the fuel diluter 51, and parallel diversion passages 56 are defined. Then, the fuel off-gas introduced into the fuel diluter 51 from the introduction pipe 52 and the oxidizing off-gas introduced from the introduction pipe 53 are divided into the respective diversion passages 56, and both off-gases are separated in the diversion passages 56. It is designed to be mixed. The respective diversion passages 56 optimize the flow of the mixed off gas by effectively using the entire area of the internal space of the fuel diluter 51, thereby improving the dilution efficiency.
JP 2007-179894 A JP 2005-158576 A

  However, in the exhaust gas processing apparatus disclosed in Patent Document 2, the introduction pipe 52 is provided only at one place, and only a space is provided between the introduction pipe 52 and each inlet of each of the diversion passages 56. Since it was provided, there were the following problems. That is, when the oxidizing off gas indicated by the arrow Q introduced from the introduction pipe 53 into the fuel diluter 51 is the fuel off gas indicated by the arrow P, the flow of the fuel off gas shifts to the shunt passage 56 on the upper side of the figure and the flow of the oxidizing off gas. Tends to be shifted to the diversion passage 56 on the lower side in the figure. For this reason, the proper diversion of each of the fuel off-gas and the oxidation off-gas to each diversion passage 56 is hindered, and the mixing of the fuel off-gas and the oxidation off-gas is not performed properly. There was a problem that it was not possible to carry out each of the flow paths 56 properly.

  An object of the present invention is to solve the above-described problems in the prior art, to properly mix fuel off-gas and oxidizing off-gas, and to properly dilute hydrogen gas with oxidizing off-gas. An object of the present invention is to provide an exhaust gas dilution device for a battery.

In order to solve the above-mentioned problems, the invention according to claim 1 is directed to a fuel in which a fuel off-gas containing hydrogen gas discharged from an outlet on the fuel electrode side of a fuel cell is introduced into a dilution container having a gas dilution chamber. A dilution gas outlet for providing an off-gas inlet and an oxidizing off-gas inlet for introducing an oxidizing off-gas discharged from an outlet on the oxidant electrode side of the fuel cell, and for discharging the diluted gas diluted in the dilution chamber to the outside In the fuel cell exhaust gas diluting apparatus, a diversion passage is formed in the diluting chamber to divide the oxidizing off gas introduced from the oxidizing off gas introduction port into a plurality of portions. A plurality of fuel off-gas inlets are disposed at a plurality of locations corresponding to the respective diversion passages, and the corresponding Are arranged to enter respectively in the flow path, the inlet of each diversion passage is set to be positioned on the same plane, the connected to the oxidizing off gas inlet oxide offgas inlet pipe, the plane The gist of this is that it is inclined .
According to a second aspect of the present invention, there is provided a fuel off-gas inlet for introducing a fuel off-gas including hydrogen gas discharged from an outlet on the fuel electrode side of the fuel cell into a dilution container having a gas dilution chamber, and a fuel cell. Exhaust gas dilution of a fuel cell provided with an oxidation off gas introduction port for introducing oxidation off gas discharged from an outlet on the oxidant electrode side of the fuel cell and provided with a dilution gas discharge port for discharging dilution gas diluted in the dilution chamber to the outside In the apparatus, a diversion passage is formed in the dilution chamber for diverting a plurality of the oxidation offgas introduced from the oxidation offgas introduction port, and each of the diversion passages is provided in a direction intersecting with the flow direction of the oxidation offgas. The fuel off-gas inlets are formed at a plurality of locations corresponding to the respective diversion passages, and enter the corresponding diversion passages. The oxidizing off-gas introduction port is provided so as to correspond to a diversion passage located at an end of the plurality of diversion passages in a direction orthogonal to the diversion direction, and an inlet of each of the diversion passages The gist of the present invention is that the distance between the end edge of the dilution vessel and the inner surface of the dilution vessel is set to be continuously reduced as the distance from the oxidizing off-gas introduction port increases.

According to a third aspect of the present invention, in the first or second aspect , a fuel off-gas branch pipe is disposed in the dilution chamber, and a plurality of branch nozzles for branching the fuel off-gas are separated from the branch pipe. The gist is that they are connected.

The invention according to claim 4 is characterized in that, in claim 3 , each of the diversion nozzles is disposed so as to be inclined with respect to the axis of the diversion passage so that the fuel off-gas is swirled in the diversion passage. And

According to a fifth aspect of the present invention, in the third or fourth aspect of the present invention, in the lower part of the dilution container, a retention chamber for retaining the fuel off-gas is defined, and the fuel off-gas distribution pipe is provided at the gas outlet of the retention chamber. The gist is that they are connected.

A sixth aspect of the present invention is that, in any one of the first to fifth aspects, the position of the oxidizing off gas inlet and the position of the dilution gas outlet are offset so as not to face each other. And

The gist of the seventh aspect of the present invention is that, in any one of the first to sixth aspects, the oxidizing off-gas introduction port is disposed at a plurality of locations.
(Function)
In the present invention, since the fuel off-gas inlets are arranged at a plurality of positions apart from the dilution container, the fuel off-gas is supplied from each inlet into the dilution chamber. For this reason, the fuel off-gas is properly dispersed and mixed with the oxidizing off-gas introduced into the dilution chamber, and the hydrogen gas contained in the fuel off-gas is appropriately diluted with the oxidizing off-gas.

  According to the present invention, the fuel off-gas and the oxidizing off-gas can be properly mixed, and the hydrogen gas can be appropriately diluted with the oxidizing off-gas.

Hereinafter, an embodiment of an exhaust gas dilution apparatus for a fuel cell embodying the present invention will be described with reference to FIGS.
The exhaust gas dilution device 11 of the fuel cell according to this embodiment includes a rectangular box-shaped dilution container 12 as shown in FIG. 1, and a dilution chamber 15 is formed therein. Below the dilution container 12, an auxiliary container 13 having a horizontally long rectangular tube shape is provided. A retention chamber 14 is formed in the auxiliary container 13. An inlet 13b formed near the left end of the bottom plate 13a of the auxiliary container 13 is used for introducing a fuel off-gas containing hydrogen gas discharged from an outlet on the fuel electrode side of a fuel cell (not shown) into the retention chamber 14. A fuel off gas introduction pipe 16 is connected. Near the right end of the partition plate 13c that partitions the residence chamber 14 and the dilution chamber 15, there is an inlet 13d for guiding the fuel off gas in the residence chamber 14 into the dilution chamber 15 as shown in FIG. It is formed in the place.

  An oxidizing off-gas containing oxygen gas discharged from an outlet on the oxidant electrode side of a fuel cell (not shown) is supplied to the diluting chamber 15 into an oxidizing off-gas inlet 12b formed at the upper end of the right side plate 12a shown in the drawing of the dilution container 12. An oxidizing off-gas introduction pipe 17 for guiding the inside of the gas is connected horizontally. The dilution gas discharge port 12d formed at the lower end of the illustrated left side plate 12c of the dilution container 12 mixes the fuel off-gas and the oxidation off-gas inside the dilution chamber 15 and dilutes the hydrogen gas with another gas. A dilution gas discharge pipe 18 for discharging the diluted gas to the outside is connected.

  The two inlets 13d formed in the partition plate 13c shown in FIG. 3 are connected in parallel so that the fuel off-gas distribution pipes 21 (only one is shown in FIG. 3) are directed upward. Has been. A fuel off-gas diversion nozzle 22 is connected to both the diversion pipes 21 in parallel and horizontally. In this embodiment, five diverter nozzles 22 are connected to a single fuel offgas diverter pipe 21 at a predetermined pitch in the vertical direction. From the tip openings of a total of ten diverter nozzles 22, that is, from the fuel offgas inlet 22a. A fuel off gas is introduced into the dilution chamber 15.

  Inside the dilution container 12, there are rectifying cylinders 23 having a substantially horizontal rectangular tube shape for forming a plurality of horizontal diversion passages 23a inside the dilution chamber 15, and parallel to each other at a plurality of locations. Contained horizontally. In this embodiment, as shown in FIG. 2, the rectifying cylinders 23 are vertically arranged in five locations in the dilution container 12 so as to respectively correspond to the ten fuel off-gas diversion nozzles 22 and horizontally. It is housed in 10 places in 2 places. As shown in FIG. 2, the four corners of the rectifying cylinder 23 are formed in a quadrant shape. As shown in FIG. 1, the tip of the fuel off-gas diversion nozzle 22 is inserted into the inlet of the rectifying cylinder 23 by a predetermined depth. Between the edge e1 on the inlet side of the rectifying cylinder 23 and the right side plate 12a of the dilution container 12, the oxidation offgas introduced into the dilution chamber 15 from the oxidation offgas introduction port 12b is separated into the respective portions. A gas flow path 24 for leading to the flow path 23a is provided. Further, the mixed off-gas discharged from the outlet of the diversion passage 23a is merged between the outlet side edge e2 of the rectifying cylinder 23 and the left side plate 12c of the dilution container 12 to discharge the dilution gas. A gas flow path 25 for leading to the pipe 18 is formed.

Next, the operation of the exhaust gas dilution device 11 configured as described above will be described.
In a state where the fuel cell is in operation, the fuel off-gas containing hydrogen gas discharged from the outlet on the fuel electrode side of the fuel cell is introduced from the fuel off-gas introduction pipe 16 into the retention chamber 14 of the auxiliary container 13. . In this staying chamber 14, the fuel off-gas is diffused, depressurized and decelerated, and flows toward the inlet 13d. Since the fuel off-gas stays in the residence chamber 14 for a long time, the hydrogen gas contained in the fuel off-gas is appropriately mixed with other gases such as nitrogen gas and diluted. The fuel off-gas that has entered the two inlets 13d flows upward in the two fuel off-gas branch pipes 21 and then splits from the fuel off-gas inlet 22a of each branch nozzle 22 into the rectifying cylinder 23. It is introduced into the path 23a.

  On the other hand, the oxidizing off gas discharged from the outlet on the oxidant electrode side of the fuel cell is supplied to the gas flow path 24 of the dilution container 12 through the oxidizing off gas introduction pipe 17. The oxidant off-gas is supplied by being divided and supplied to the diversion passages 23a of the respective rectification cylinders 23, and is mixed with the fuel off-gas discharged from the diversion nozzle 22 to be discharged from the diversion passages 23a of the rectification cylinders 23. From the exhaust pipe 18 to the outside.

According to the exhaust gas dilution device of the fuel cell of the above embodiment, the following effects can be obtained.
(1) In the above embodiment, a plurality of diversion nozzles 22 are connected to the two fuel off-gas diversion pipes 21 connected to the introduction port 13d of the auxiliary container 13 so as to divert the fuel off-gas. did. For this reason, the fuel off-gas containing hydrogen gas can be diversified, and the oxidizing off-gas introduced into the dilution chamber 15 of the dilution container 12 can be effectively used for diluting the hydrogen gas. Dilution efficiency can be improved.

  (2) In the above embodiment, since the rectifying cylinder 23 is accommodated in the dilution chamber 15 of the dilution container 12 and the diversion passages 23a are formed at a plurality of locations, the gas is discharged from the oxidizing off-gas introduction pipe 17 The oxidizing off gas guided to the flow path 24 can be properly diverted. Therefore, combined with the effect of dividing the fuel off gas by the diversion nozzle 22, the mixing of the oxidizing off gas and the fuel off gas and the dilution of the hydrogen gas can be performed equally and appropriately in each of the diversion passages 23a.

  (3) In the above embodiment, the auxiliary container 13 is provided at the lower part of the dilution container 12, the fuel gas is once introduced from the fuel off-gas introduction pipe 16 into the residence chamber 14, the gas is diffused, decelerated and decompressed, It was made to guide to the inlet 13d. For this reason, the fuel off-gas can be retained in the retention chamber 14 for a long time, and the mixing of the hydrogen gas with another gas such as nitrogen gas can be promoted to appropriately dilute the hydrogen gas.

  (4) In the above-described embodiment, the tip of the diversion nozzle 22 is inserted by a predetermined depth into the inlet side of the diversion passage 23a of the rectifying cylinder 23. Therefore, the ejector function causes each diversion passage 23a to enter the diversion passage 23a. The flow of fuel off gas can be generated positively. As a result, the oxidizing off gas introduced into the gas flow path 24 from the oxidizing off gas introduction pipe 17 can be forcibly sucked into the branch passages 23a of the respective rectifying cylinders 23, and the oxidizing off gas can be effectively used. Thus, the function of diluting hydrogen gas can be improved.

  (5) In the above embodiment, each of the rectifying cylinders 23 is formed in the shape of a quarter-arc-shaped corner as shown in FIG. 2, so that the resistance of the mixed off-gas flow path in the shunt path 23a. , And the flow of the mixed off gas in the diversion passage 23a can be performed smoothly, and the pressure loss can be reduced.

  (6) In the above embodiment, as shown in FIG. 1, the oxidation off-gas introduction pipe 17 and the dilution gas discharge pipe 18 are offset so as not to face each other. Dilution can be appropriately performed by being guided equally to the diversion passages 23a of the rectifying cylinder 23.

  Next, another embodiment of an exhaust gas dilution device for a fuel cell embodying the present invention will be described in sequence with reference to FIGS. Detailed description of the same parts as those in the above embodiment will be omitted.

  In the embodiment shown in FIG. 4, the oxidizing off gas inlets 12 b are formed at a predetermined equal pitch in the vertical direction with respect to the right side plate 12 a of the dilution container 12. A branch pipe 31 that is branched and connected to the oxidizing off-gas introducing pipe 17 is connected to the oxidizing off-gas introducing port 12b. The number of the fuel off gas branch nozzles 22 and the number of the oxidizing off gas inlets 12b are set to be the same. The dilution gas discharge pipe 18 is disposed at the center in the vertical direction of the left side plate 12c. The axial line of the flow dividing pipe 31 and the axial line of the flow dividing nozzle 22 are offset in the direction orthogonal to the paper surface in the direction orthogonal to the axial line.

  In the exhaust gas dilution device 11 described above, the oxidizing off gas is more evenly divided from the plurality of oxidizing off gas introduction ports 12b to the branch passage 23a of the rectifying cylinder 23. Therefore, the oxidizing off gas can be used more effectively. The ability to dilute hydrogen gas can be improved.

  In the embodiment shown in FIG. 5, the exhaust gas dilution device 11 is configured upside down, and the drain hole 12 e is formed in the bottom plate of the dilution container 12. By this drain hole 12e, the generated water contained in the oxidizing off gas introduced into the dilution container 12 from the oxidizing off gas introduction pipe 17 is discharged to the outside.

  In the exhaust gas dilution device 11 described above, the auxiliary container 13 is disposed above the dilution container 12, and the fuel off-gas distribution pipe 21 and the fuel off-gas distribution nozzle 22 are positioned below the auxiliary container 13. For this reason, the speed at which hydrogen gas that is lighter than other gases such as nitrogen gas contained in the fuel off-gas flows toward the fuel off-gas diversion nozzle 22 becomes slower than the other gases. Therefore, the ratio of the volume of the other gas to the volume of the hydrogen gas is increased, so that the hydrogen gas is more appropriately diluted.

  As shown in FIG. 6 (a), the oxidizing off-gas introduction pipe 17 is connected in an inclined state, and the oxidizing off-gas is on the same plane on the inlet side of the diversion passage 23a of the rectifying cylinder 23 as indicated by an arrow. The oxidizing off gas may be supplied obliquely with respect to the edge e1 located at the position. In this case, compared with the case where the oxidation off-gas introduction pipe 17 is connected horizontally, the oxidation off-gas can be more evenly divided into the respective diversion passages 23a.

  As shown in FIG. 6B, the inlet 12b formed in the right side plate 12a of the dilution container 12 is formed long in the vertical direction, and a gas diffusion chamber 26a is formed outside the inlet 12b. A case 26 may be attached, and the oxidizing off-gas introduction pipe 17 may be connected to the central portion of the case 26 in the vertical direction.

  In this case, the oxidizing off gas that has entered the diffusion chamber 26 a of the case 26 from the oxidizing off gas introduction pipe 17 is diffused in the vertical direction, and then is evenly divided into the diversion passages 23 a of the rectifying cylinders 23.

  As shown in FIG. 7A, the distance between the edge e1 located on the same plane on the inlet side of the branch passage 23a of the rectifying cylinder 23 and the inner surface of the right side plate 12a of the dilution container 12 May be set such that the lower rectifying cylinder 23 continuously decreases.

  In this other embodiment, even if the oxidation off-gas introduction pipe 17 is in a horizontal state as shown in FIG. 7A, the fuel off-gas flowing from the oxidation off-gas introduction pipe 17 into the gas flow path 24 is supplied to each rectification cylinder. Since it becomes easy to flow equally into the branch passage 23a of the body 23, it is preferable.

  As shown in FIG. 7B, the tip of the fuel off-gas diversion nozzle 22 is inclined with respect to the axis of the diversion passage 23a, and the diversion nozzle 22 is displaced from the center of the rectifying cylinder 23 in the direction perpendicular to the paper surface. Alternatively, the fuel off-gas that has flowed from the diversion nozzle 22 into the diversion passage 23a of the rectifying cylinder 23 may be swirled. In this case, the mixing of the fuel off-gas and the oxidizing off-gas in the branch passage 23a can be performed more appropriately by the swirling flow, and the hydrogen gas dilution function can be further improved.

Although not shown, in FIG. 1, the oxidizing off-gas introduction pipe 17 may be connected to the vertical center of the right side plate 12 a of the dilution container 12.
The number of the fuel off-gas diversion nozzles 22 may be any number, for example, 2 to 9, 11 to 20.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a longitudinal sectional view showing an embodiment of an exhaust gas dilution device according to the present invention. FIG. 2 is a cross-sectional view of the exhaust gas dilution device of FIG. 1. The separation perspective view of a fuel off gas distribution pipe, a fuel off gas distribution nozzle, and a cylinder for rectification. The longitudinal cross-sectional view of the exhaust-gas dilution apparatus which shows another embodiment of this invention. The longitudinal cross-sectional view of the exhaust-gas dilution apparatus which shows another embodiment of this invention. (A), (b) is a fragmentary longitudinal cross-sectional view of the exhaust-gas dilution apparatus which shows another embodiment of this invention. (A), (b) is a fragmentary longitudinal cross-sectional view of the exhaust-gas dilution apparatus which shows another embodiment of this invention. The longitudinal cross-sectional view of the conventional exhaust gas dilution apparatus. FIG. 9 is a plan sectional view of the exhaust gas dilution device of FIG. 8. The longitudinal cross-sectional view of another conventional exhaust gas dilution apparatus.

Explanation of symbols

  e1, e2 ... edge, 11 ... exhaust gas dilution device, 12 ... dilution container, 12b ... oxidizing off gas inlet, 12d ... dilution gas outlet, 14 ... dwell chamber, 15 ... dilution chamber, 16 ... fuel off gas inlet pipe, 17 ... Oxidizing off-gas introduction pipe, 22 ... Dividing nozzle, 22a ... Fuel off-gas introducing port, 23a ... Dividing passage.

Claims (7)

A fuel off-gas inlet for introducing a fuel off-gas containing hydrogen gas discharged from an outlet on the fuel electrode side of the fuel cell is provided in a dilution container having a gas dilution chamber, and discharged from an outlet on the oxidant electrode side of the fuel cell. In the exhaust gas dilution device for a fuel cell, provided with an oxidation off-gas introduction port for introducing the oxidation off-gas, and provided with a dilution gas discharge port for discharging the dilution gas diluted in the dilution chamber to the outside,
In the dilution chamber, a diversion passage for dividing the oxidation off gas introduced from the oxidation off gas introduction port into a plurality of portions is formed,
Each of the branch passages is formed in a direction intersecting with the flow direction of the oxidizing off gas,
The fuel off-gas introduction port is disposed at a plurality of locations corresponding to each of the diversion passages, and is disposed to enter the corresponding diversion passage ,
An inlet of each of the diversion passages is set so as to be positioned on the same plane, and an oxidizing off gas introduction pipe connected to the oxidizing off gas introduction port is inclined with respect to the plane . Exhaust gas dilution device. A fuel off-gas inlet for introducing a fuel off-gas containing hydrogen gas discharged from an outlet on the fuel electrode side of the fuel cell is provided in a dilution container having a gas dilution chamber, and discharged from an outlet on the oxidant electrode side of the fuel cell. In the exhaust gas dilution device for a fuel cell, provided with an oxidation off-gas introduction port for introducing the oxidation off-gas, and provided with a dilution gas discharge port for discharging the dilution gas diluted in the dilution chamber to the outside,
In the dilution chamber, a diversion passage for dividing the oxidation off gas introduced from the oxidation off gas introduction port into a plurality of portions is formed,
Each of the branch passages is formed in a direction intersecting with the flow direction of the oxidizing off gas,
The fuel off-gas introduction port is disposed at a plurality of locations corresponding to each of the diversion passages, and is disposed to enter the corresponding diversion passage,
The oxidizing off gas introduction port is provided so as to correspond to a diversion passage located at an end with respect to a direction orthogonal to the diversion direction among the plurality of diversion passages, and an edge of an inlet of each of the diversion passages; An exhaust gas dilution device for a fuel cell, characterized in that the distance from the inner surface of the dilution container is set to be continuously smaller as the distance from the oxidizing off-gas introduction port is increased. 3. The fuel off-gas branch pipe is disposed in the dilution chamber according to claim 1, and a plurality of branch nozzles for branching the fuel off-gas are connected to the branch pipe so as to be separated from each other. Fuel cell exhaust gas dilution device. 4. The exhaust gas dilution device for a fuel cell according to claim 3 , wherein each of the diverting nozzles is disposed so as to be inclined with respect to the axis of the diverting passage so that the fuel off-gas is swirled in the diverting passage. . 5. A retention chamber for retaining a fuel off gas is defined in a lower portion of the dilution container according to claim 3 , and the fuel off gas branch pipe is connected to a gas outlet port of the retention chamber. Fuel cell exhaust gas dilution device. In any one of claims 1 to 5, wherein the position of the position and the diluent gas outlet of the oxidation off-gas inlet, exhaust gas dilution device for a fuel cell characterized by being offset so as not to face each other . The exhaust gas dilution device for a fuel cell according to any one of claims 1 to 6 , wherein the oxidation off-gas introduction port is disposed at a plurality of locations apart from each other.

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