JP6026691B1 - Fuel cell system - Google Patents

Abstract

A fuel cell system that suppresses temperature non-uniformity among a plurality of fuel cell stacks while maintaining a combustion battery cell stack at a high temperature. A first combustion space 41A of a combustor 40 is disposed on one side of a stack unit 19 constituted by a first fuel cell stack 16 and a second fuel cell stack 16, and a first unit is disposed on the other side. Two combustion spaces 42A are arranged. The stack unit 19 and the combustor 40 can exchange heat. [Selection] Figure 1

Description

  The present invention relates to a fuel cell system.

  Some fuel cell systems have a plurality of fuel cell stacks. For example, a plurality of fuel cell stacks are multi-staged, and unreacted fuel in the anode off-gas discharged from the preceding fuel cell stack is used for power generation in the subsequent fuel cell stack. Proposed. Thus, when it has a some fuel cell stack, the electric current at the time of electric power generation may differ depending on the control method of the load current of a fuel cell stack, for example. In that case, the amount of heat generated from the fuel cell stacks is different, and the temperature becomes nonuniform in the vicinity of each fuel cell stack. In this case, the power generation efficiency differs between the fuel cell stacks. Even if the load current control method is the same among a plurality of fuel cell stacks, if the temperature of the fuel cell stack becomes non-uniform due to changes in gas flow rate, etc., not only the power generation performance will change, but also power generation is possible. There may be a difference in the time to reach the temperature.

  For example, in patent document 1, the gas flow path which flows the combustion gas discharged | emitted from the combustion part on the outer periphery of a fuel cell stack is provided, and the temperature variation of a combustion battery cell stack is suppressed. Moreover, in patent document 1, although it has several fuel cell stacks, it is not comprised by multistage. Each off gas discharged from each fuel cell stack is used for combustion, and does not have a configuration for guiding the off gas to a combustor or a portion other than the combustor.

JP 2007-242565 A

  The present invention has been made in consideration of the above facts, and provides a fuel cell system that suppresses temperature non-uniformity among a plurality of fuel cell stacks while maintaining the combustion cell stack at a high temperature. Objective.

  According to a first aspect of the present invention, there is provided a fuel cell system including a first fuel cell stack that generates electric power by reacting fuel gas and air, and the first fuel cell stack arranged side by side. A second fuel cell stack that forms a stack unit together with the first fuel cell stack by generating power by reacting with the first anode off gas discharged from the fuel electrode of the fuel cell stack, and the second fuel cell A first combustion space capable of exchanging heat with the first fuel cell stack and the second fuel cell stack on one side of the second anode off-gas discharged from the stack and sandwiching the stack unit, and the other side And a combustor in which a second combustion space capable of exchanging heat with the first fuel cell stack and the second fuel cell stack is formed. That.

  In the fuel cell system according to claim 1, the first fuel cell stack and the second fuel cell stack are arranged side by side to constitute a stack unit. In the combustor, the second anode off gas burns. In the combustor, a first combustion space is formed on one side and a second combustion space is formed on the other side across the stack unit, and heat exchange with the stack unit is possible.

  As described above, the stack unit is disposed at a position sandwiched between the first combustion space and the second combustion space, and heat exchange is possible. Therefore, heat from the first fuel cell stack and the second fuel cell stack can be obtained. Can be suppressed and temperature non-uniformity in the first fuel cell stack and the second fuel cell stack can be suppressed.

  In the fuel cell system according to a second aspect of the present invention, the combustor is formed with a first connection space that is disposed along the stack unit and communicates with the first combustion space and the second combustion space. .

  In the fuel cell system according to the second aspect of the present invention, since the first connection space that communicates with the first combustion space and the second combustion space is disposed along the stack unit, heat dissipation from the stack unit is further reduced. Can be suppressed.

  In the fuel cell system according to claim 3, the first connection space is arranged on the first fuel cell stack side, and the combustion point of the second anode off gas is the second combustion gas in the first combustion space. A flue gas pipe that is formed on the fuel cell stack side and discharges flue gas is formed on the second fuel cell stack side of the second combustion space.

  In the fuel cell system according to the third aspect of the present invention, in the combustor, the combustion point formed on the second fuel cell stack side of the first combustion space becomes a high temperature, and the combustion exhaust gas is discharged from the combustion point to the first fuel. It goes to the battery cell stack side and moves to the second combustion space through the first connection space. And it moves toward the 2nd fuel cell stack side in the 2nd combustion space, and is discharged from the flue gas pipe formed in the 2nd fuel cell stack side. The temperature in the combustor includes the second fuel cell stack side of the first combustion space, the first fuel cell stack side of the first combustion space, the first fuel cell stack side of the second combustion space, and the second combustion space. It decreases in order of the second fuel cell stack side. The second fuel cell stack is adjacent to the combustion point of the first combustion space having the highest temperature and the portion immediately before discharge to the exhaust gas pipe of the second combustion space having the lowest temperature. On the other hand, the first fuel cell stack is adjacent to the downstream portion from the combustion point of the first combustion space, and is adjacent to the upstream portion from the exhaust in the second combustion space.

  Therefore, the heat received by each of the first fuel cell stack and the second fuel cell stack is leveled, and uneven temperature in the first fuel cell stack and the second fuel cell stack can be suppressed. .

  In the fuel cell system according to a fourth aspect of the present invention, the combustor includes an outer peripheral space that includes the first combustion space and the second combustion space as a part and surrounds an outer periphery of the stack unit. .

  According to the fuel cell system of the fourth aspect of the invention, since the outer periphery of the stack unit is surrounded by the outer peripheral space formed in the combustor, the first fuel cell stack and the second fuel cell stack Heat dissipation can be further suppressed to maintain a high temperature.

  In the fuel cell system according to claim 5, the combustion point of the second anode off gas is formed at an intermediate portion of the first fuel cell stack and the second fuel cell stack in the first combustion space. A combustion exhaust pipe for discharging combustion exhaust gas is formed in the second combustion space.

  In the fuel cell system according to the fifth aspect of the present invention, the temperature in the combustor is the highest at the combustion point at the intermediate portion between the first fuel cell stack and the second fuel cell stack in the first combustion space. The portion where the combustion exhaust gas is discharged at the intermediate portion between the first fuel cell stack and the second fuel cell stack in the two combustion spaces, that is, the portion where the combustion exhaust pipe is formed becomes low temperature. Accordingly, the heat received by each of the first fuel cell stack and the second fuel cell stack is leveled, and uneven temperature in the first fuel cell stack and the second fuel cell stack can be suppressed. .

  The fuel cell system according to a sixth aspect of the invention is characterized in that the second combustion space is provided with a partition member that lengthens the passage length of the combustion exhaust gas.

  In the fuel cell system according to the sixth aspect of the present invention, the partition member that lengthens the flow path length of the combustion exhaust gas is provided in the second combustion space farther from the combustion point than the first combustion space. Therefore, the amount of heat exchange between the second combustion space and the stack unit can be increased compared to the case where no partition member is provided.

  According to the fuel cell system of the present invention, it is possible to suppress temperature nonuniformity among the plurality of fuel cell stacks while maintaining the combustion battery cell stack at a high temperature.

1 is a schematic configuration diagram of a fuel cell system according to a first embodiment. It is a figure which shows the example (A)-(C) of the discharge | release part in 1st Embodiment. It is a schematic block diagram of the fuel cell system which concerns on the modification of 1st Embodiment. It is a schematic block diagram of the fuel cell system which concerns on 2nd Embodiment. It is a figure which shows the example (A)-(C) of the 1st discharge | release part in 2nd Embodiment, and a 2nd discharge | release part. It is a schematic block diagram of the fuel cell system which concerns on the modification of 2nd Embodiment.

[First Embodiment]
Hereinafter, a first embodiment of the present invention will be described in detail with reference to the drawings.

  FIG. 1 shows a schematic configuration of a fuel cell system 10A according to the present embodiment. The fuel cell system 10A according to the present embodiment includes a vaporizer 12, a reformer 14, a first fuel cell stack 16, a second fuel cell stack 18, and a combustor 40 as main components. .

  One end of the source gas pipe P1 is connected to the vaporizer 12, and the other end of the source gas pipe P1 is connected to a gas source (not shown). From the gas source, methane is sent to the vaporizer 12 by the blower B1. The vaporizer 12 is connected to a water supply pipe P2. Water (liquid phase) is sent from the water supply pipe P2 to the vaporizer 12 by the pump P. In the vaporizer 12, water is vaporized. For the vaporization, the heat of the combustion exhaust gas G10 discharged from the combustor 40 described later can be used. In this embodiment, methane is used as the raw material gas, but it is not particularly limited as long as it can be reformed, and a hydrocarbon fuel can be used. Examples of the hydrocarbon fuel include natural gas, LP gas (liquefied petroleum gas), coal reformed gas, lower hydrocarbon gas, and the like. Examples of the lower hydrocarbon gas include lower hydrocarbons having 4 or less carbon atoms such as methane, ethane, ethylene, propane, and butane, and methane used in the present embodiment is preferable. The hydrocarbon fuel may be a mixture of the above-described lower hydrocarbon gas.

  Methane and water vapor are sent from the vaporizer 12 to the reformer 14 via the pipe P3. The reformer 14 is heated by heat exchange with a combustor 40 described later. In the reformer 14, methane is reformed to generate a fuel gas G1 containing hydrogen and having a temperature of about 600 ° C. One end of a fuel gas pipe P4 is connected to the reformer 14. The other end of the fuel gas pipe P4 is connected to the anode (fuel electrode) 16A of the fuel cell stack 16. The fuel gas G1 generated by the reformer 14 is supplied to the anode 16A through the fuel gas pipe P4.

  The first fuel cell stack 16 is a solid oxide fuel cell stack (SOFC: Solid Oxide Fuel Cell) and has a plurality of stacked fuel cells. The operating temperature of the first fuel cell stack 16 is set to about 650 ° C.

  Each fuel cell of the first fuel cell stack 16 includes an electrolyte membrane, and an anode (fuel electrode) 16A and a cathode (air electrode) 16B laminated on the front and back surfaces of the electrolyte membrane, respectively. Yes.

  One end of an air pipe P5 is connected to the cathode 16B of the first fuel cell stack 16, and a blower B2 is connected to the other end of the air pipe P5. The air G5 sent from the blower B2 is supplied to the cathode 16B through the air pipe P5. The air G5 flowing through the air pipe P5 may be heated by exchanging heat with a combustion exhaust gas G10 described later.

In the cathode 16B, as shown in the following formula (1), oxygen in the air and electrons react to generate oxygen ions. The generated oxygen ions reach the anode 16A of the first fuel cell stack 16 through the electrolyte membrane.

(Air electrode reaction)
1 / 2O ₂ + 2e ⁻ → O ²⁻ (1)

Cathode off-gas is discharged from the cathode 16B.

  On the other hand, in the anode 16A of the first fuel cell stack 16, as shown in the following equations (2) and (3), oxygen ions that have passed through the electrolyte membrane react with hydrogen and carbon monoxide in the fuel gas. Water (steam) and carbon dioxide and electrons are generated. Electrons generated at the anode 16A move from the anode 16A through the external circuit to the cathode 16B, thereby generating electric power in each fuel cell stack. Each fuel cell stack generates heat during power generation.

(Fuel electrode reaction)
H ₂ + O ²⁻ → H ₂ O + 2e ⁻ (2)
CO + O ²⁻ → CO ₂ + 2e ⁻ (3)

  One end of an anode offgas pipe P7 is connected in parallel to the anode 16A. The first anode off gas G3 is discharged from the anode 16A to the anode off gas pipe P7. The first anode off gas G3 contains unreacted hydrogen, unreacted carbon monoxide, carbon dioxide, water vapor, and the like.

The other end of the anode off gas pipe P7 is connected to an anode 18A of a second fuel cell stack 18 described later, and the first anode off gas G3 is sent to the anode 18A.

  The second fuel cell stack 18 has the same configuration as the first fuel cell stack 16, and includes an anode 18A corresponding to the anode 16A and a cathode 18B corresponding to the cathode 16B. In the second fuel cell stack 18, power generation is performed by the same reaction as in the first fuel cell stack 16. The second fuel cell stack 18 is arranged side by side with the first fuel cell stack 16, and the first fuel cell stack 16 and the second fuel cell stack 18 constitute a stack unit 19. The stack unit 19 can exchange heat between each of the first fuel cell stack 16 and the second fuel cell stack 18 with each of the first combustion space 41A and the second combustion space 42A of the combustor 40 described later. It has become. The heat exchange may be radiation or heat transfer through a heat transfer material.

  The combustor 40 includes a first combustion unit 41 disposed on one side of the stack unit 19 and a second combustion unit 42 disposed on the other side. The first combustion part 41 and the second combustion part 42 are each made of a metal box, the first combustion space 41A is formed inside the first combustion part 41, and the second combustion is inside the second combustion part 42. A space 42A is formed. The first combustion unit 41 and the second combustion unit 42 are connected via the first connection unit 44 at the end on the first fuel cell stack 16 side. The 1st connection part 44 is arrange | positioned along the stack unit 19, and the 1st connection space 44A connected with each of the 1st combustion space 41A and the 2nd combustion space 42A is formed in the inside.

  One end of the cathode offgas pipe P9-2 and one end of the anode offgas pipe P8 are connected to the end of the first combustion unit 41 on the second fuel cell stack 18 side. The other end of the cathode offgas pipe P9-2 is connected to the cathode 18B. The first combustion section 41 is formed with a discharge section 45 that discharges the cathode off gas G9-2 into the first combustion space 41A. The cathode offgas G9-2 discharged from the cathode 18B passes through the cathode offgas pipe P9-2 and is discharged from the discharge portion 45 to the first combustion space 41A.

  The other end of the anode off gas pipe P8 is connected to the anode 18A. The first combustion section 41 is formed with a discharge section 46 that discharges the second anode off gas G8 into the first combustion space 41A. Unreacted hydrogen and carbon monoxide in the second anode off-gas G8 released from the discharge part 46 burn with oxygen in the cathode off-gas G9-2 as a combustion gas and the vicinity of the discharge part 46 as a combustion point.

  As shown in FIG. 2A, the paths to the discharge parts 45 and 46 are the cathode offgas pipe P9-2 and the second anode offgas pipe P8 from the outside of the first combustion part 41 to the discharge parts 45 and 46. 2B, or as shown in FIG. 2B, the cathode offgas pipe P9-2 and the second anode offgas pipe P8 are drawn inside the first combustion section 41 to the discharge sections 45 and 46. It may be extended. Further, as shown in FIG. 2C, a flow path 43 </ b> A of the cathode offgas pipe P <b> 9-2 is provided inside the first combustion unit 41 and led to the discharge unit 45, and the second combustion is performed inside the first combustion unit 41. The flow path 43B of the anode off-gas pipe P9-2 may be provided so as to be led to the discharge portion 46 and to discharge the second anode off-gas G8 into the first combustion space 41A.

  A combustion exhaust pipe P <b> 10 is connected to the second combustion unit 42. The combustion exhaust gas pipe P10 is connected to the end of the second combustion unit 42 on the second fuel cell stack 18 side. The combustion exhaust gas G10 is discharged from the combustion exhaust gas pipe P10.

  Next, the operation of the fuel cell system 10A of the present embodiment will be described.

  The air G5 sent out at a predetermined flow rate by the blower B2 is supplied to the cathode 16B and used for power generation, and then the cathode offgas G9-1 is sent out to the cathode 18B via the cathode offgas pipe P9-1. Cathode off gas G9-1 is used for power generation at cathode 18B, and cathode off gas G9-2 is discharged from cathode 18B. The cathode offgas G9-2 is sent to the first combustion section 41 of the combustor 40 through the cathode offgas pipe P9-2, and is discharged from the discharge section 45 into the first combustion space 41A.

  On the other hand, the methane sent out by the blower B1 is supplied to the vaporizer 12. Further, the vaporizer 12 is supplied with water (liquid phase) by a pump P and is heated by combustion exhaust gas (not shown). Thereby, water is vaporized, and the heated methane and water vapor are sent to the reformer 14 through the pipe P3. The reformer 14 is heated by heat exchange with the combustor 40, and methane is reformed into the fuel gas G1. The fuel gas G1 is supplied to the anode 16A via the fuel gas pipe P4 and is used for power generation. From the anode 16A, the first anode offgas G3 containing fuel such as unreacted hydrogen is discharged and supplied to the anode 18A via the anode offgas pipe P7. The first anode off gas G3 is subjected to power generation at the anode 18A, and the second anode off gas G8 is discharged from the anode 18A.

  The second anode off gas G8 is sent to the first combustion section 41 of the combustor 40 through the anode off gas pipe P8, discharged from the discharge section 46 into the first combustion space 41A, and burns in the vicinity of the discharge section 46. Thereby, the temperature in the vicinity of the discharge part 46 rises. The combustion exhaust gas G10 flows from the second fuel cell stack 18 side of the first combustion space 41A to the first fuel cell stack 16 side, and flows into the second combustion space 42A through the first connection space 44A. And it flows from the 1st fuel cell stack 16 side of the 2nd combustion space 42A to the 2nd fuel cell stack 18 side, and is discharged from combustion exhaust pipe P10A. The temperatures in the combustor 40 are the first fuel space 41A side of the first combustion space 41A close to the combustion point of the combustion exhaust gas G10, the first fuel cell stack 16 side of the first combustion space 41A, and the second combustion space. It decreases in the order of the first fuel cell stack 16 side of 42A and the second fuel cell stack 18 side of the second combustion space 42A.

  In this embodiment, since the stack unit 19 is disposed at a position sandwiched between the first combustion space 41A and the second combustion space 42A, heat dissipation from the first fuel cell stack and the second fuel cell stack. Can be suppressed and high temperature can be maintained. In addition, since each of the first fuel cell stack 16 and the second fuel cell stack 18 is heat-exchanged with the combustor 40, the temperature unevenness in the first fuel cell stack and the second fuel cell stack is reduced. Can be suppressed.

  Further, in the present embodiment, since the first connection space 44A that communicates with the first combustion space 41A and the second combustion space 42A is disposed along the stack unit 19, heat dissipation from the stack unit 19 is further suppressed. can do.

  Further, in the present embodiment, the second fuel cell stack 18 is in the vicinity of the combustion point of the first combustion space 41A, which is the highest temperature of the combustor 40, and to the combustion exhaust pipe P10 of the second combustion space 42A, which is the lowest temperature. Adjacent to the part just before discharge to delivery. On the other hand, for the first fuel cell stack 16, the first combustion space 41A is adjacent to the downstream portion from the combustion point, and the second combustion space is adjacent to the upstream portion from the discharge. Therefore, the heat received by each of the first fuel cell stack 16 and the second fuel cell stack 18 is leveled, and uneven temperature in the first fuel cell stack 16 and the second fuel cell stack 18 is suppressed. can do.

  As shown in FIG. 3, the second combustion space 42 </ b> A of the second combustion unit 42 is provided with a partition member 42 </ b> W so that the flow between the connection portion with the first connection portion 44 and the combustion exhaust gas pipe P <b> 10. You may lengthen the road. Thus, by increasing the length of the flow path in the second combustion space 42A, the amount of heat exchange between the second combustion space 42A having a temperature lower than that of the first combustion space 41A and the stack unit 19 can be increased. The partition member 42W may be provided only on the second fuel cell stack 18 side, which is a relatively low temperature portion in the second combustion space 42A.

  In the present embodiment, the discharge portions 45 and 46 and the combustion exhaust pipe P10 are provided on the second fuel cell stack 18 side, and the first connection portion 44 is provided on the first fuel cell stack 16 side. 45, 46 and the flue gas pipe P10 may be provided on the first fuel cell stack 16 side, and the first connecting portion 44 may be provided on the second fuel cell stack 18 side. Further, in the present embodiment, the discharge parts 45 and 46 are provided in the first combustion part 41 and the combustion exhaust gas pipe P10 is provided in the second combustion part 42. However, the discharge parts 45 and 46 are provided in the second combustion part 42, The combustion exhaust pipe P <b> 10 may be provided in the first combustion unit 42.

  Further, the fuel cell system 10A of the present embodiment has been described with an example of a two-stage configuration in which the first fuel cell stack 16 is a front stage and the second fuel cell stack 18 is a rear stage. The present invention can also be applied to a fuel cell system including a three-stage configuration having another fuel cell stack at the rear stage of the stack 18 and a fourth-stage fuel cell stack.

[Second Embodiment]
Next, a second embodiment of the present invention will be described. In the present embodiment, the same parts as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  The fuel cell system 10B of the present embodiment is different from the first embodiment in the shape of the combustor and the introduction positions of the second anode offgas pipe P8 and the cathode offgas G9-2. As shown in FIG. 4, the combustor 50 includes a first connection part 44 that connects the first combustion part 41 and the second combustion part 42 at the end on the first fuel cell stack 16 side, and a second fuel cell. A second connection portion 48 that connects the first combustion portion 41 and the second combustion portion 42 at the end on the cell stack 18 side is provided. The first connecting portion 44 is disposed along the first fuel cell stack 16 side of the stack unit 19, and the second connecting portion 48 is disposed along the second fuel cell stack 18 side of the stack unit 19. Yes. A first connection space 44 </ b> A is formed in the first connection portion 44, and a second connection space 48 </ b> A is formed in the second connection portion 48. The first connection space 44A and the second connection space 48A communicate with the first combustion space 41A and the second combustion space 42A, and the first combustion space 41A, the first connection space 44A, the second combustion space 42A, and the second combustion space 42A. An outer peripheral space 50A surrounding the outer periphery of the stack unit 19 is configured by the two connection spaces 48A.

  One end of a cathode offgas pipe P9-2 and one end of an anode offgas pipe P8 are connected to an intermediate portion of the first fuel cell stack 16 and the second fuel cell stack 18 of the first combustion unit 41. The other end of the cathode offgas pipe P9-2 is connected to the cathode 18B. The first combustion section 41 is formed with a discharge section 52 that discharges the cathode off gas G9-2 into the first combustion space 41A. The cathode offgas G9-2 discharged from the cathode 18B passes through the cathode offgas pipe P9-2 and is discharged from the discharge portion 52 to the first combustion space 41A.

  The other end of the anode off gas pipe P8 is connected to the anode 18A. The first combustion section 41 is formed with a discharge section 54 that discharges the second anode off gas G8 into the first combustion space 41A. Unreacted hydrogen and carbon monoxide in the second anode off-gas G8 released from the emission part 54 are oxidized by the cathode off-gas G9-2 and burned with the vicinity of the emission part 54 as a combustion point.

  As shown in FIG. 5A, the path to the discharge parts 52 and 54 includes the cathode offgas pipe P9-2 and the second anode offgas pipe P8 from the outside of the first combustion part 41 to the discharge parts 52 and 54. As shown in FIG. 5B, the cathode offgas pipe P9-2 and the second anode offgas pipe P8 are drawn inside the first combustion section 41 and extended to the discharge sections 52 and 54. May be present. Furthermore, as shown in FIG. 5C, a flow path 53 of the cathode offgas pipe P <b> 9-2 is provided inside the first combustion unit 41 and led to the discharge unit 52, and the second combustion is performed inside the first combustion unit 41. The second anode off gas G8 may be discharged into the first combustion space 41A by providing the flow path 55 of the anode off gas pipe P8 to the discharge portion 54.

  A combustion exhaust pipe P <b> 10 is connected to the second combustion unit 42. The combustion exhaust gas pipe P <b> 10 is connected to an intermediate portion between the first fuel cell stack 16 and the second fuel cell stack 18 of the second combustion unit 42. The combustion exhaust gas G10 is discharged from the combustion exhaust gas pipe P10.

  Next, the operation of the fuel cell system 10B of the present embodiment will be described.

  The cathode off gas G9-2 is sent to the first combustion unit 41 of the combustor 40 via the cathode off gas pipe P9-2, and is discharged from the discharge unit 52 into the first combustion space 41A. On the other hand, the second anode off-gas G8 is sent to the first combustion section 41 of the combustor 40 through the anode off-gas pipe P8, discharged from the discharge section 54 into the first combustion space 41A, and burns in the vicinity of the discharge section 54. . Thereby, the temperature in the vicinity of the discharge part 54 rises. The combustion exhaust gas G10 flows from the intermediate portion of the first fuel cell stack 16 and the second fuel cell stack 18 in the first combustion space 41A to the first connection space 44A side and the second connection space 48A side, Each flows into the second combustion space 42A via the connection space 44A and the second connection space 48A. And it moves to the intermediate part of the 1st fuel cell stack 16 and the 2nd fuel cell stack 18 of the 2nd combustion space 42A, and is discharged from combustion exhaust pipe P10A. The temperature in the combustor 40 decreases in the order of the first combustion space 41A, the first connection space 44A, the second connection space 48A, and the second combustion space 42A.

  In the present embodiment, since the stack unit 19 is disposed so as to be surrounded by the outer peripheral space 50A, heat dissipation from the first fuel cell stack and the second fuel cell stack can be suppressed to maintain a high temperature. it can. In addition, since each of the first fuel cell stack 16 and the second fuel cell stack 18 is heat-exchanged with the combustor 40, the temperature unevenness in the first fuel cell stack and the second fuel cell stack is reduced. Can be suppressed.

  Further, in the present embodiment, since the high temperature portion and the low temperature portion are disposed in the intermediate portion between the first fuel cell stack 16 and the second fuel cell stack 18, the first fuel cell stack 16, the second fuel cell The heat received by each of the stacks 18 is leveled, and uneven temperature in the first fuel cell stack 16 and the second fuel cell stack 18 can be suppressed.

  In this embodiment, as shown in FIG. 6, the partition member 42W may be provided in the second combustion space 42A of the second combustion section 42 to lengthen the flow path in the second combustion space 42A. . Thus, by increasing the length of the flow path in the second combustion space 42A, the amount of heat exchange between the second combustion space 42A having a temperature lower than that of the first combustion space 41A and the stack unit 19 can be increased.

  In the present embodiment, the discharge parts 52 and 54 are provided on the first combustion space 41A side and the combustion exhaust pipe P10 is provided on the second combustion space 42A side. However, the discharge parts 52 and 54 are provided on the second combustion space 42A side. The combustion exhaust pipe P10 may be provided on the first combustion space 42A side.

The fuel cell of the present invention is not limited to a solid oxide fuel cell (SOFC), but may be another fuel cell such as a molten carbonate fuel cell (MCFC). May be.

Furthermore, the present invention is not limited to the first and second embodiments described above, and can be implemented by a person skilled in the art in combination with known devices within the technical idea of the present invention. For example, the installation and combination of heat exchangers can be set in various ways.

10A, 10B Fuel cell system 16 First fuel cell stack 16A Anode (fuel electrode)
18 Second fuel cell stack 18A Anode (fuel electrode)
19 Stack unit 40 Combustor 41A First combustion space 42A Second combustion space 50 Combustor 50A Outer peripheral space G3 First anode off gas G8 Second anode off gas P10 Combustion exhaust pipe

Claims (6)

A first fuel cell stack that generates electricity by reacting fuel gas and air;
Arranged side by side with the first fuel cell stack, the air reacts with the first anode off gas discharged from the fuel electrode of the first fuel cell stack to generate electric power, and the stack together with the first fuel cell stack A second fuel cell stack constituting the unit;
A second anode off gas discharged from the second fuel cell stack is combusted, and the first fuel cell stack and the second fuel cell stack can exchange heat with each other across the stack unit. A combustor in which one combustion space and a second combustion space capable of exchanging heat with the first fuel cell stack and the second fuel cell stack are formed on the other side;
A fuel cell system comprising:   2. The fuel cell system according to claim 1, wherein the combustor includes a first connection space that is disposed along the stack unit and communicates with the first combustion space and the second combustion space. The first connection space is disposed on the first fuel cell stack side, and the combustion point of the second anode off gas is formed on the second fuel cell stack side of the first combustion space to discharge combustion exhaust gas. The fuel cell system according to claim 2, wherein a combustion exhaust gas pipe to be formed is formed on the second fuel cell stack side of the second combustion space.   2. The fuel cell system according to claim 1, wherein the combustor is formed with an outer peripheral space that includes the first combustion space and the second combustion space as a part and surrounds an outer periphery of the stack unit.   A combustion point of the second anode off gas is formed in an intermediate portion of the first fuel cell stack and the second fuel cell stack in the first combustion space, and a combustion exhaust pipe for discharging combustion exhaust gas is provided in the first combustion space. The fuel cell system according to claim 4, wherein the fuel cell system is formed in two combustion spaces. 6. The fuel cell system according to claim 3, wherein the second combustion space is provided with a partition member that lengthens a flow path length of the combustion exhaust gas.

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