JP5109242B2 - Apparatus and fuel cell system for supplying fuel gas to a fuel cell - Google Patents

Description

  The present invention relates to a fuel gas supply device that supplies fuel gas for power generation to a fuel cell, and a fuel cell system that generates power by supplying gas to the fuel cell.

  A fuel cell generally has a single cell stack structure, and a single cell sandwiches a MEA (Membrance Electrode Assembly) composed of an electrolyte layer that forms a catalyst layer on the surface thereof with a gas flow path forming member for fuel gas and oxidizing gas. To do. In a fuel cell having such a single-cell stacked structure, a supply system for each gas is provided to supply both fuel gas and oxidizing gas to each single cell.

  By the way, not all of the supplied fuel gas is subjected to an electrochemical reaction between hydrogen and oxygen in each single cell, and a part of hydrogen in the fuel gas is left unreacted as a single cell. Discharged from the fuel cell. For this reason, in order to use this unreacted hydrogen effectively, a circulation system for circulating the fuel gas discharged from the fuel cell is provided in the fuel gas supply system (for example, Patent Document 1).

JP 2001-266922 A

  In this patent document, a circulation system pipe line is connected to an ejector provided in a fuel gas supply system path, and exhausted fuel gas is circulated from the circulation system to the supply system using a negative pressure suction force by the ejector. . The exhaust fuel gas thus circulated is mixed with the fuel gas supplied from the gas supply source and supplied to the fuel cell.

  The exhausted fuel gas that circulates through the ejector in this way is a gas that has once passed through the fuel cell, and the following problems have been pointed out. When the exhaust fuel gas is circulated and supplied, the fuel cell is naturally in the power generation state, and the temperature rises with the power generation. Therefore, the discharged fuel gas reaches the ejector in a state where the temperature is raised by receiving the heat of the fuel cell whose temperature has been increased, and is circulated to the fuel gas supply system.

  In a fuel cell, when a hydrogen-containing gas is supplied to the anode and an oxygen-containing gas (for example, air) is supplied to the cathode, water is generated at the anode by an electrochemical reaction between hydrogen and oxygen. It is contained in the exhaust fuel gas as water vapor. Therefore, this water vapor flows back to the fuel gas supply system through the ejector together with the discharged fuel gas, and is mixed with the fuel gas supplied from the gas supply source.

  In this case, when the temperature of the fuel gas supplied from the gas supply source is low, condensation of water vapor in the exhausted fuel gas and eventually freezing of the condensed water can occur in the ejector that is the circulating point of the exhausted fuel gas. In particular, the ejector has a nozzle for fuel gas injection, and performs high-speed gas injection from a small-diameter nozzle hole, so that the injected gas tends to be at a lower temperature. Further, since the discharged fuel gas is guided to the tip of the nozzle, condensation and freezing in the vicinity of the tip of the nozzle and in the ejector internal flow path on the downstream side of the nozzle are more likely to occur. When such a situation such as condensation or freezing occurs in the internal flow path, a shortage of gas supply is caused due to a reduction in the flow path area, and stable power generation of the fuel cell is hindered.

  The present invention has been made to solve the above-described problems when adopting an ejector in a circulation system for circulating fuel gas discharged from a fuel cell to a gas supply system, and to improve the reliability of circulation supply of exhaust fuel gas. For that purpose.

  In order to solve at least a part of such problems, in the fuel cell system of the present invention, when supplying fuel gas for power generation to the fuel cell and generating power, the fuel gas is supplied to the fuel cell by the fuel gas supply system. At the same time, the fuel gas discharged from the fuel cell is sucked by the ejector in the fuel gas supply system path and circulated to the fuel cell. Efficient use of exhausted fuel gas will be achieved through such recirculation of exhausted fuel gas. In this case, the fuel gas is determined by the configuration of the single cell that is a power generation unit. For example, in the case of a single cell including a hydrogen ion permeable electrolyte membrane, hydrogen gas is supplied as the fuel gas. Further, a gas containing hydrogen and other gases may be supplied as a fuel gas.

  The recirculation of the exhaust fuel gas to the fuel gas supply system is brought about as follows by suction of the exhaust fuel gas by the ejector of the fuel gas supply system path. The ejector ejects fuel gas from the nozzles that the ejector has, and the ejected fuel gas reaches the ejection gas flow path located on the downstream side of the nozzle, passes through the flow path, and flows downstream of the ejector. The ejector generates a negative pressure at the tip of the nozzle by jetting the fuel gas from the nozzle, and the negative pressure causes a suction action of surrounding gas (exhaust fuel gas in the present invention).

  In the ejector used in the fuel cell system of the present invention, the exhaust fuel gas from the circulation system flows into the gas inflow chamber of the ejector, passes through the gas inflow chamber, and communicates with the ejection gas flow path on the tip end side of the nozzle. It is sucked by the jet gas flow that reaches the nozzle and reaches the jet gas flow path from the nozzle. In this case, if the gas inflow chamber is connected to the circulation path downstream from the communication portion, the flow of the discharged fuel gas from the gas inflow chamber to the communication portion is directed upstream. Then, after the exhaust fuel gas reaches the communicating portion, the direction of the flow is changed to the downstream side in the same direction as the fuel gas jet gas flow from the nozzle, and the jet gas downstream of the nozzle together with the fuel gas jetted from the nozzle It flows downstream of the ejector through the flow path.

  In the above ejector, since the gas inflow chamber is formed around the jet gas flow channel with the outer wall of the jet gas flow channel being separated, when the exhaust fuel gas flows into the gas flow chamber and causes the above recirculation flow The heat exchange between the exhaust fuel gas in the gas inflow chamber around the jet gas channel and the gas passing through the jet gas channel can be performed through the outer wall of the jet gas channel. In this case, the discharged fuel gas flows into the gas inflow chamber in a state where the temperature is somewhat high because it is a gas discharged from the fuel cell in the power generation state. On the other hand, the temperature of the gas passing through the ejection gas passage, that is, the mixed gas of the fuel gas and the exhaust fuel gas is lower than the temperature of the exhaust fuel gas if the temperature of the fuel gas is lower than that of the exhaust fuel gas. Therefore, when the temperature of the supplied fuel gas is low, the temperature of the mixed gas passing through the jet gas passage is raised by the heat of the exhaust fuel gas in the gas inflow chamber.

  As described above, since the fuel gas discharged from the fuel cell contains water vapor, the water vapor passes through the ejection gas flow path together with the fuel gas ejected from the nozzle of the ejector. For this reason, when the fuel gas is at a low temperature, the water vapor may be cooled by the gas and condensed or frozen in the ejection gas flow path. However, in the present invention, as described above, heat exchange by the high-temperature exhaust fuel gas is enabled in the ejection gas passage, so that the effectiveness of avoiding condensation and freezing of water vapor in the ejection gas passage is enhanced. As a result, since the flow area of the ejection gas flow path can be maintained, the reliability of the circulation and supply of the exhaust fuel gas is enhanced, which is beneficial for avoiding the shortage of gas supply in the fuel cell and stabilizing the power generation of the fuel cell.

  In forming the gas inflow chamber around the ejection gas flow path, it can be formed as a single hollow room surrounding the ejection gas flow path, and a plurality of rooms divided into two, three, etc. It can also be formed along the flow path.

  In addition, when the exhaust fuel gas flows along with the jet gas from the ejector nozzle downstream of the nozzle, the direction of the flow of the exhaust fuel gas is set upstream by connecting the connection portion of the gas inflow chamber and the circulation system path downstream from the communicating portion. From the side to the downstream side. Therefore, there are the following advantages.

  The exhausted fuel gas contains the fuel gas not used for the electrochemical reaction in the fuel cell and the water as the water vapor described above. In many cases, the fuel gas material (eg, hydrogen) has a lower mass than water. For this reason, when the exhaust fuel gas changes its flow direction at the communicating portion, the inertial force acting on the water wins, so this water (steam) tends to stay at the change point of the flow direction. It is possible to suppress the water vapor from flowing into the ejection gas flow path downstream of the nozzle. In this case, the water vapor remaining at the conversion point can be cooled and condensed by the fuel gas passing through the nozzle. In addition, the exhaust fuel gas that has flowed into the gas inflow chamber is cooled by the heat exchange described above, and the water vapor in the exhaust fuel gas is condensed in the gas inflow chamber and reaches the point where the gas flow is changed in the communication portion. It is possible. However, the water condensed in this way can effectively drop the water staying at the change point of the flow direction along the circulation path by connecting the circulation path to the gas inflow chamber from the vertically lower side. it can.

  In the fuel cell system of the present invention described above, in the gas inflow chamber of the ejector provided in the gas supply path, the outer wall of the ejection gas flow path has an area increasing portion that increases the contact area with the gas passing through the gas inflow chamber. It can also be done. In this way, the contact area with the exhaust fuel gas flowing into the gas inflow chamber increases, so heat exchange through the outer wall of the jet gas passage can be promoted, so that it is effective for avoiding condensation and freezing of water vapor in the jet gas passage. The property is further enhanced, which is preferable. It is convenient to use a fin protruding from the outer wall of the ejection gas flow path as the area increasing portion.

  The present invention can be applied as a fuel gas supply device that supplies fuel gas for power generation to a fuel cell.

  Examples of the present invention will be described below. FIG. 1 is a block diagram schematically showing the configuration of a fuel cell system 100 according to an embodiment. The fuel cell system 100 mainly includes a fuel cell 10, a hydrogen tank 20, a blower 30, a control unit 200, and a humidifier 60.

  The fuel cell 10 is a hydrogen separation membrane type fuel cell, and has a stack structure in which a plurality of single cells as constituent units are stacked. Each single cell has a configuration in which a hydrogen electrode (hereinafter referred to as an anode) and an oxygen electrode (hereinafter referred to as a cathode) are arranged with an electrolyte membrane interposed therebetween. A fuel cell containing hydrogen (hereinafter referred to as an anode gas) is supplied to the anode side of each single cell, and an oxidizing gas containing oxygen is supplied to the cathode side, whereby an electrochemical reaction proceeds, and a fuel cell. 10 generates electricity. The electric power generated in the fuel cell 10 is supplied to a predetermined load (not shown) connected to the fuel cell 10. In addition to the hydrogen separation membrane fuel cell described above, the fuel cell 10 includes various types such as a solid polymer fuel cell, an alkaline aqueous electrolyte type, a phosphoric acid electrolyte type, or a molten carbonate electrolyte type. The fuel cell can be used.

  The blower 30 is a device for supplying air as an oxidizing gas to the cathode side of the fuel cell 10. The blower 30 is connected to the cathode side of the fuel cell 10 via the cathode gas supply channel 34. A humidifier 60 is provided in the cathode gas supply channel 34. The air compressed by the blower 30 is supplied to the fuel cell 10 after being humidified by the humidifier 60. The fuel cell 10 is provided with a cathode exhaust gas passage 36, and exhaust gas from the cathode after being subjected to an electrochemical reaction (hereinafter referred to as cathode exhaust gas) is discharged to the outside through the cathode exhaust gas passage 36. The

  The hydrogen tank 20 is a storage device that stores high-pressure hydrogen gas, and is connected to the anode side of the fuel cell 10 via an anode gas supply channel 24. On the anode gas supply channel 24, an anode gas cutoff valve 230 and a regulator 22 are provided in the vicinity of the hydrogen tank 20. The anode gas cutoff valve 230 is provided upstream of the regulator 22 in the hydrogen gas flow direction. When the anode gas cutoff valve 230 is in the closed state, the supply of hydrogen gas from the hydrogen tank 20 is shut off, and when the anode gas cutoff valve 230 is in the open state, the hydrogen gas from the hydrogen tank 20 is supplied. The opening and closing of the anode gas cutoff valve 230 is controlled by the control unit 200.

  The high-pressure hydrogen gas supplied from the hydrogen tank 20 to the anode gas supply channel 24 is regulated by the regulator 22. The conditioned hydrogen gas is supplied to the anode side of the fuel cell 10 as an anode gas. What is necessary is just to set the pressure after pressure regulation suitably according to the magnitude | size etc. of the load connected to the fuel cell 10. FIG.

  The anode gas supply flow path 24 from the hydrogen tank 20 to the anode of the fuel cell 10 corresponds to the fuel gas supply system in the present invention.

  Instead of the hydrogen tank 20, hydrogen is generated by a reforming reaction using alcohol, hydrocarbon, aldehyde or the like as a raw material, and supplied to the anode side of the fuel cell 10 via the anode gas cutoff valve 230 and the regulator 22. It is good. Further, depending on the properties of the electrolyte membrane, it is possible to supply a fuel gas containing hydrogen and other gases.

  On the anode side of the fuel cell 10, a purge valve 240 is provided in the anode exhaust gas passage 26 branched from the gas circulation passage 28. The purge valve 240 discharges (purges) exhaust gas from the anode after being subjected to an electrochemical reaction (hereinafter referred to as anode exhaust gas) from the gas circulation channel 28 to the outside via the anode exhaust gas channel 26. Is for. Such anode exhaust gas purging is effective in the following cases.

  During the operation of the fuel cell system 100, the anode exhaust gas may contain unnecessary gas other than hydrogen. Examples of the unnecessary gas include nitrogen that has permeated the electrolyte membrane from the cathode side. This unnecessary gas is not consumed and circulates through the gas circulation passage 28 in the fuel cell system 100. As a result, the concentration of the unnecessary gas in the anode gas gradually increases, and the power generation efficiency of the fuel cell 10 decreases. Therefore, the control unit 200 controls the purge valve 240 to periodically discharge the anode exhaust gas containing unnecessary gas.

  In addition, when using a type other than the hydrogen separation membrane type fuel cell as the fuel cell 10 or depending on the environment in which the fuel cell 10 is used, other components may be mixed in the anode exhaust gas as unnecessary gas.

  In the anode exhaust gas flow path 26, a gas circulation flow path 28 connected to the anode gas supply flow path 24 is provided from a position upstream of the purge valve 240 in the flow direction in which the anode exhaust gas is discharged. The gas circulation channel 28 is for returning the anode exhaust gas to the anode gas supply channel 24, and includes an ejector 70 provided in the anode gas supply channel 24 and a gas provided in the anode exhaust gas channel 26. The liquid separator 250 is connected to circulate and supply anode exhaust gas as indicated by an arrow HJ in the figure. As a result, the hydrogen gas contained in the anode exhaust gas circulates and is used again for power generation as the anode gas.

  The gas-liquid separator 250 has a configuration in which the gas passage chamber 251 and the liquid storage portion 252 below the gas passage chamber 251 are combined. After the anode exhaust gas from the anode exhaust gas passage 26 passes through the gas passage chamber 251, the gas circulation passage Lead to 28. The gas passage chamber 251 has a flow path bent by a number of partition plates, and while the anode exhaust gas passes through the bent flow path, the water vapor and moisture in the gas are separated from the gas to some extent, and the liquid storage section 252 below is separated. Drop the water. The liquid storage unit 252 includes a drain pipe 253, and discharges the stored water to the outside through opening and closing of a drain valve 254 in the pipeline.

  The gas-liquid separator 250 is disposed almost directly below the ejector 70 in the anode gas supply channel 24. Therefore, the gas circulation channel 28 causes the anode exhaust gas to flow into the ejector 70 from the vertically lower side.

  The control unit 200 is configured as a logic circuit centered on a microcomputer, and more specifically, a CPU (not shown) that executes predetermined calculations and the like according to a preset control program, and executes various calculation processes by the CPU. A ROM (not shown) in which control programs and control data necessary for the above are stored in advance, and a RAM (not shown) in which various data necessary for performing various arithmetic processes in the CPU are temporarily read and written. And an input / output port (not shown) for inputting / outputting various signals. The control unit 200 acquires information related to the load request and outputs a drive signal to each unit constituting the fuel cell system 100, that is, the blower 30 and the humidifier 60, and the operation state of the entire fuel cell system 100 is determined. Control these in consideration. For example, the anode gas cutoff valve 230 is closed to stop the supply of the anode gas, or the purge valve 240 is opened to discharge the above-described unnecessary gas. Further, the drainage valve 254 is opened according to the state of moisture storage in the gas-liquid separator 250, and moisture is discharged from the liquid storage unit 252.

  Next, the ejector 70 that causes the circulation of the anode exhaust gas will be described. Control will be described. FIG. 2 is a cross-sectional view illustrating the ejector 70 while magnifying the main part thereof, and FIG. 3 is an explanation for explaining the inside of the ejector 70 by breaking the housing along the line 3-3 in FIG. FIG.

  As shown in these drawings, the ejector 70 includes an upstream housing 71 and a downstream housing 72, and is configured by fitting and fixing both housings. The upstream housing 71 includes a pipe line 73 connected to the path of the anode gas supply flow path 24, and the pipe tip is a nozzle 74. The nozzle 74 is formed so as to gradually reduce the pipe diameter of the pipe 73, and ejects the anode gas flowing through the anode gas supply flow path 24, thereby generating an ejected gas flow JF as indicated by the white arrow in the figure.

  The downstream housing 72 has a hollow structure, and a partition gas 75 forms an ejection gas flow path 76 and a gas inflow chamber 77 therein. The partition wall 75 has a taper portion 75a that gradually widens on the nozzle 74 side, and is positioned on the downstream side of the nozzle 74 so that the taper portion 75a overlaps with the nozzle 74 leaving a gap 78. Therefore, the ejection gas flow path 76 is located downstream of the nozzle 74 and allows the anode gas of the ejection gas flow JF ejected by the nozzle 74 to pass downstream. The downstream side of the jet gas channel 76 is an enlarged channel 79 whose pipe diameter gradually increases, and this enlarged channel 79 is connected to the anode gas supply channel 24 downstream of the ejector.

  The ejector 70 is provided with a gas inflow chamber 77 so as to surround the ejection gas flow path 76 with a partition wall 75 therebetween, and the gas inflow chamber 77 is passed through the opening 80 on the bottom surface side of the downstream side housing 72. Is connected. Therefore, the anode exhaust gas flows into the gas inflow chamber 77 from the gas circulation passage 28 connected to the ejector 70 vertically downward.

  In the gas inflow chamber 77, the tapered portion 75 a side of the partition wall 75 serves as a communication portion 81 that communicates with the gap 78 described above and the ejection gas flow path 76. As shown in the enlarged view of FIG. 2, the communication portion 81 has an outer wall as a tapered guide portion 82, and the gas (anode exhaust gas) in the gas inflow chamber 77 is ejected from the nozzle 74 to the ejection gas channel 76. The gas inflow chamber 77 communicates with the ejection gas flow path 76 at the tip end side of the nozzle 74 so as to be sucked by the gas flow JF. In this case, the communication part 81 communicates the gas inflow chamber 77 to the ejection gas flow path 76 on the upstream side of the opening 80, so that the anode exhaust gas flowing into the gas inflow chamber 77 from the opening 80 is guided toward the upstream side. However, the gas flow is led to the taper portion 75a side of the partition wall 75, the gas flow is changed to the downstream side, and then sucked into the jet gas flow JF through the gap 78.

  The fuel cell system 100 having the ejector 70 configured as described above circulates the anode exhaust gas as follows. The ejector 70 continuously ejects the anode gas from the small diameter nozzle 74. Since the nozzle 74 has a small diameter, the anode gas is ejected to the downstream side of the nozzle as a high-speed ejection gas flow JF, reaches the ejection gas flow path 76 downstream of the nozzle, passes through the flow path, and reaches the anode downstream of the ejector. It flows to the gas supply channel 24. The ejector 70 generates a negative pressure at the tip of the nozzle by the ejection of the anode gas from the small-diameter nozzle 74, and sucks the anode exhaust gas in the gas inflow chamber 77 through the gap 78 and the communication portion 81 by this negative pressure.

  The anode exhaust gas flows into the gas inflow chamber 77 from the gas circulation flow path 28, proceeds in the gas inflow chamber 77 toward the communicating portion on the nozzle side as indicated by the arrow Y1 in the figure, and the gas flow ejected from the nozzle 74 Suctioned by JF through gap 78. In this case, since the gas inflow chamber 77 is connected to the gas circulation channel 28 on the downstream side of the communication portion 81, the anode exhaust gas flow from the gas inflow chamber 77 to the communication portion 81 is directed upstream. Then, after the anode exhaust gas reaches the communication portion 81, the flow direction of the anode exhaust gas is changed to the downstream side in the same direction as the jet gas flow JF from the nozzle 74, and from the nozzle 74 as shown by an arrow Y2 in the figure. Together with the ejected anode gas, it flows to the downstream side of the ejector 70 through the ejected gas flow path 76 downstream of the nozzle.

  In this way, when the anode exhaust gas is circulated, the gas inflow chamber 77 is formed so as to surround the ejection gas flow path 76, and therefore, the anode exhaust gas in the gas inflow chamber 77 surrounding the ejection gas flow path 76 and Heat exchange with the gas passing through the ejection gas flow path 76 is possible via the partition wall 75. In this case, the anode exhaust gas flows into the gas inflow chamber 77 in a state in which the anode exhaust gas is heated to a certain degree because it is gas discharged from the fuel cell 10 in the power generation state. On the other hand, the temperature of the gas passing through the ejection gas flow path 76, that is, the mixed gas of the anode gas and the anode exhaust gas ejected by the nozzle 74, is lower in the gas inflow chamber 77 than the anode exhaust gas. It becomes lower than the temperature of the anode exhaust gas. Therefore, the temperature of the mixed gas passing through the ejection gas channel 76 is raised by the heat of the anode exhaust gas in the gas inflow chamber 77.

  For this reason, even if the low-temperature anode gas and the steam-containing anode exhaust gas are mixed and passed through the jet gas channel 76, the above-described heat exchange can avoid the condensation and freezing of water vapor in the jet gas channel 76. . As a result, since the flow area of the ejection gas flow path 76 can be maintained, the reliability of the circulation supply of the anode exhaust gas is improved, the shortage of gas supply in the fuel cell 10 can be avoided, and the power generation of the fuel cell 10 is stabilized. You can also

  The ejector 70 of the present embodiment avoids water vapor aggregation and freezing in the ejection gas flow path 76 by heat exchange via the partition wall 75, but this heat exchange causes water vapor aggregation in the anode exhaust gas in the gas inflow chamber 77. It can be awakened. However, the agglomerated water is prevented from reaching the ejection gas channel 76 as follows. In other words, the ejector 70 changes the flow direction of the anode exhaust gas from the upstream side to the downstream side when flowing the anode exhaust gas together with the gas ejected from the nozzle 74 of the ejector 70, so that the communication portion 81 that is the switching portion is changed. In this case, water vapor and moisture that are heavier than the anode exhaust gas can be stopped by an inertial force larger than the inertial force acting on the gas. Then, the stopped water is guided to the opening 80 and then to the gas circulation flow path 28 by the tapered guide portion 82. For this reason, when the anode exhaust gas is caused to flow downstream together with the ejected anode gas of the ejected gas flow JF, water vapor and moisture in the anode exhaust gas can be removed in advance, so that the water vapor aggregation in the ejected gas flow path 76 is performed. And the effectiveness of avoiding freezing increases. In addition, when the gas circulation channel 28 is connected to the ejector 70, the gas circulation channel 28 is connected to the ejector 70 from the vertically lower side. It can be dropped along the line 28 and removed by the gas-liquid separator 250.

  The gas-liquid separator 250 has a simple configuration merely by joining the gas passage chamber 251 and the liquid storage unit 252, and does not have a special heat exchange configuration. The water can be effectively removed from the anode exhaust gas by dropping the water.

  Next, a modification of the ejector 70 will be described. 4 is a sectional view of the ejector 70A corresponding to FIG. 2, and FIG. 5 is an explanatory view of the ejector 70A corresponding to FIG. The ejector 70 </ b> A includes a plurality of fins 90 that protrude radially from the partition wall 75 in the gas inflow chamber 77. Since the fin 90 protrudes leaving a gap with the outer wall surface of the gas inflow chamber 77, the anode exhaust gas flows into the gas inflow chamber 77 from the gas circulation passage 28 and contacts the anode exhaust gas to communicate gas. Guide to the part 81 side. Therefore, according to the ejector 70A of this modification, the contact area of the anode exhaust gas in the gas inflow chamber 77 is increased by the outer surface area of the fin 90, so that heat exchange with the anode exhaust gas via the partition wall 75 is promoted. . As a result, the effectiveness of avoiding condensation and freezing of water vapor in the jet gas passage 76 can be further enhanced, which is preferable.

  In this modification, the fin 90 can be formed to reach the outer wall surface of the gas inflow chamber 77. If it carries out like this, the gas inflow chamber 77 will be formed in the circumference | surroundings of the ejection gas flow path 76 in the state divided | segmented into the several room. In this case, anode exhaust gas flows into the divided rooms from the gap on the left end side of the fin 90 in FIG.

  FIG. 6 is an explanatory view of an ejector 70B of another modification equivalent to FIG. The ejector 70 </ b> B includes a spiral fin 91 protruding from the partition wall 75 in the gas inflow chamber 77. Since the fin 91 spirally extends toward the nozzle 74 while leaving a gap with the outer wall surface of the gas inflow chamber 77, the inflow of anode exhaust gas from the gas circulation channel 28 to the gas inflow chamber 77 occurs. In contact with the anode exhaust gas, the gas is guided to the communicating portion 81 side in a spiral flow as indicated by an arrow Y′1 in the figure. Therefore, according to the ejector 70B of this modification, the contact area of the anode exhaust gas in the gas inflow chamber 77 can be increased by the outer surface area of the fin 91, and the path through which the anode exhaust gas flows can be lengthened. Heat exchange with the anode exhaust gas via 75 is further promoted. As a result, the effectiveness of avoiding condensation and freezing of water vapor in the jet gas passage 76 can be further enhanced, which is preferable.

  As mentioned above, although the Example of this invention was described, this invention is not restricted to above-described embodiment, In the range which does not deviate from the summary, it is possible to implement in various aspects.

1 is a block diagram schematically showing a configuration of a fuel cell system 100 of an example. FIG. It is sectional drawing explaining the ejector 70, enlarging the principal part. FIG. 3 is an explanatory diagram for explaining an internal state of the ejector 70 by breaking a housing along a line 3-3 in FIG. 2. It is sectional drawing of the ejector 70A equivalent to FIG. It is explanatory drawing of the ejector 70A equivalent to FIG. It is explanatory drawing of the ejector 70B of another modification equivalent to FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Fuel cell 20 ... Hydrogen tank 22 ... Regulator 24 ... Anode gas supply flow path 26 ... Anode exhaust gas flow path 28 ... Gas circulation flow path 30 ... Blower 34 .. Cathode gas supply flow path 36 ... Cathode exhaust gas flow path 60 ... Humidifier 70, 70A, 70B ... Ejector 71 ... Upstream housing 72 ... Downstream housing 73 ... Pipe 74 ... Nozzle 75 ... Bulk 75a ... Tapered portion 76 ... Blowout gas flow path 77 ... Gas inflow chamber 78 ... Gap 79 ... Expanded flow path 80 ... Opening 81 .. Communication part 82 ... Guide part 90 ... Fin 91 ... Fin 100 ... Fuel cell system 200 ... Control part 230 ... Anode gas shutoff valve 240 ... Purge valve 250 ... Gas-liquid separator 251 ... Gas passage chamber 252 ... Liquid reservoir 253 ... Drain pipe 254 ... Drain valve JF ... Gas flow

Claims (4)

A fuel cell system comprising a fuel cell, and generating power by supplying fuel gas for power generation to the fuel cell,
A fuel gas supply system for supplying the fuel gas to the fuel cell;
A fuel gas discharged from the fuel cell is sucked by an ejector provided in a route of the fuel gas supply system and circulated to the fuel gas supply system, and a circulation system for circulating fuel gas is provided.
The ejector is
A nozzle for jetting fuel gas;
An ejection gas passage that is located downstream of the nozzle to form a passage passage for the ejected fuel gas and that allows the fuel gas to pass downstream;
A gas inflow chamber into which exhaust fuel gas flows from the circulation system;
A communication portion that communicates the gas inflow chamber with the ejection gas channel on the tip end side of the nozzle so that the gas in the gas inflow chamber is sucked into the ejection gas flow reaching the ejection gas channel from the nozzle. ,
The gas inflow chamber is formed around the ejection gas flow path with an outer wall of the ejection gas flow path interposed therebetween, and is connected to the circulation path downstream from the communication portion.
The path of the circulation system is connected to the gas inflow chamber from the vertically lower side,
The ejection gas flow path has an area increasing portion on its outer wall that increases an area of contact with the gas flowing into the gas inflow chamber and passing through the gas inflow chamber. The fuel cell system according to claim 1, wherein
The gas inflow chamber is formed so as to surround the ejection gas flow path. The fuel cell system according to claim 1 or 2, wherein
The area increasing portion spirals a gas path that flows into the gas inflow chamber and passes through the gas inflow chamber by a spiral fin protruding from the outer wall of the ejection gas flow path to the gas inflow chamber. A fuel cell system that increases the contact area by forming the contact area . A fuel gas supply device for supplying fuel gas for power generation to a fuel cell,
A fuel gas supply path to the fuel cell;
A fuel gas discharged from the fuel cell is sucked by an ejector provided in a route of the fuel gas supply system and circulated to the fuel gas supply system, and a circulation system for circulating fuel gas is provided.
The ejector is
A nozzle for ejecting fuel gas passing through the path of the fuel gas supply system;
An ejection gas passage located downstream of the nozzle and forming a passage for the ejected fuel gas;
A gas inflow chamber for receiving an inflow of the exhaust fuel gas from the circulation system;
A communication portion that communicates the gas inflow chamber with the ejection gas flow path on the tip side of the nozzle so that the gas in the gas inflow chamber is sucked into the ejection gas flow from the nozzle;
The gas inflow chamber is formed around the ejection gas flow path with an outer wall of the ejection gas flow path interposed therebetween, and is connected to the circulation path downstream from the communication portion.
The path of the circulation system is connected to the gas inflow chamber from the vertically lower side,
The fuel gas supply device for a fuel cell, wherein the ejection gas flow path has an area increasing portion on an outer wall thereof for increasing a contact area with the gas flowing into the gas inflow chamber and passing through the gas inflow chamber.

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