JP5908746B2 - Fuel cell system - Google Patents

Description

  The present invention relates to a fuel cell system that generates power using a hydrocarbon fuel gas as a fuel gas.

  As a fuel cell system, one using a cell stack in which a plurality of solid oxide cells are stacked is known (for example, see Patent Document 1). In this solid oxide cell, a fuel electrode is provided on one side of a solid electrolyte that conducts oxygen ions, an air electrode is provided on the other side, and zirconia doped with yttria is generally used as an electrolyte material. Yes. In such a cell stack, electric power is generated by causing an electrochemical reaction between hydrogen, carbon monoxide, hydrocarbons in the fuel gas and oxygen in the oxidant at a high temperature of 600 to 1000 ° C. Solid oxide fuel cell systems have been developed as promising power generation technologies because they can generate power with higher power generation efficiency than other types of fuel cell systems and gas engines.

  This cell stack is composed of a collection of ceramic cells and is designed with priority given to ensuring reliability (in other words, avoiding cracking). When the reliability of the cell stack is high (that is, it is tough), there are less restrictions on the temperature distribution and temperature change rate in the cell stack, and if there are few restrictions, the heat generating part and the heat absorbing part in the fuel cell system are combined. Therefore, it is possible to suppress the heat radiation from the high temperature part storing the cell stack, and it is easy to realize a high power generation efficiency even with a small capacity. Moreover, if it can cope with a large temperature change rate, it can be operated advantageously to start / stop of the fuel cell system and load fluctuation.

In general, ceramics have the basic property that the smaller the basic size, the more difficult it is to break and the easier it is to ensure reliability. Development of the ones used has been promoted. In phosphoric acid fuel cells and molten carbonate fuel cells, the size is 1 m square, that is, the size (area) of one cell is several thousand to 10,000 cm ² , whereas the solid oxide type In the cell stack, the size (area) of one cell is developed as several tens to several hundreds cm ² . Therefore, in the solid oxide fuel cell system, the power generation capacity in a single cell stack must be reduced. If the area of one cell is increased in order to increase the power generation capacity, there arises a problem that the reliability of the cell decreases and the manufacturing yield decreases. For this reason, there is a strong demand for a technique for obtaining a desired power generation capacity using a plurality of solid oxide cell stacks with limited outputs.

  In order to satisfy such a demand, for example, as shown in FIG. 12, a fuel cell module assembly for obtaining a desired power generation capacity is composed of N (in the figure, four) fuel cell modules A, and fuel As a gas supply system, an N-system fuel gas supply line B is provided corresponding to each fuel cell module A, and as a reformed water supply system, an N-system water supply line C is provided corresponding to each fuel cell module A. It is also conceivable that the fuel gas from each fuel gas supply line B and the reformed water from each water supply line C are supplied to the corresponding reformer P of the fuel cell module A. Throughout this specification, the fuel header and the cell stack are expressed as “fuel cell module”, and the fuel cell module with one fuel header is expressed as one fuel cell module. A fuel header provided with one cell stack and a fuel header provided with two or more cell stacks are all included in the concept of one fuel cell module. In such a configuration, each fuel gas supply line B is provided with a fuel gas pump D and a gas flow sensor E, each water supply line C is provided with a water pump F and a water flow sensor G, and a fuel gas pump is provided for each fuel cell module A. D and the water pump F are controlled.

  Further, instead of the above-described configuration, for example, as shown in FIG. 13, a fuel cell module assembly for obtaining a desired power generation capacity is configured by N (four in the drawing) fuel cell modules A, and the fuel It is also conceivable that a common fuel gas supply line H is provided as the gas supply system, and a common water supply line I is provided as the reforming water supply system. In such a configuration, the fuel gas supply line H is provided with the fuel gas pump J and the gas flow rate sensor K, the fuel gas from the fuel gas supply line H is distributed in the gas distribution chamber L, and the gas supply branch line M is connected. The fuel cell module A is fed to the reformer P of each fuel cell module A. Further, a water pump N and a water flow sensor O are provided in the water supply line I, the reformed water from the water supply line I is distributed in the water distribution chamber Q, and is supplied to the reformer P through the water supply branch line R. It comes to send. In this case, the supply amount of fuel gas and reforming water supplied to the fuel cell module assembly (N fuel cell modules A) is controlled by one fuel gas pump J and water pump N.

JP 2008-243589 A

  However, the above-described fuel cell system has the following problems to be solved. The fuel cell system shown in FIG. 12 requires a fuel gas pump D, a gas flow rate sensor E, a water supply pump F, and a water flow rate sensor G for each fuel cell module A, so that the structure is complicated and the manufacturing cost is low. It becomes expensive. In addition, since these controls need to be performed for each fuel cell module A, the controls are complicated.

  In the fuel cell system shown in FIG. 13, only one fuel gas pump J, gas flow sensor K, water supply pump N, and water flow sensor O are used as a fuel cell module assembly (N fuel cell modules A). However, there is a problem that the structure is simple, but the branching accuracy of the fuel gas supplied to each fuel cell module A (in other words, the reformer P) is easily affected by pressure fluctuations accompanying the vaporization of the reforming water. There is. Water is dripped in the vaporizing section of the reformer P, and pressure fluctuation occurs due to the volume expansion accompanying the dripping cycle and evaporation. Further, when the fuel cell module A is operated following the load fluctuation, the pressure in the vaporization section of the reformer P further varies depending on the combustion state in the upper end portion (so-called combustion chamber) of the fuel cell module A. . Since the pressure fluctuation in the vaporization section of the reformer P occurs in the N-series fuel gas supply / branch line M, the fuel gas distribution shifts, and the fuel cell module A in which the fuel gas distribution amount becomes transiently small. Is likely to occur. Further, in long-term operation, the reforming catalyst of the reformer P is cracked, the charging state of the reforming catalyst section is changed, and the pressure loss of the reforming section of the reformer P becomes large. When the pressure loss characteristics change with time in the reforming section of such a reformer P, the distribution ratio of the amount of fuel gas supplied to each fuel cell module A changes, and a plurality of fuel cell module assemblies There is a risk that part of the fuel cell module may become inoperable.

  An object of the present invention is to provide a fuel cell system suitable for obtaining a relatively large power generation output by using a plurality of fuel cell modules having a relatively small power generation output.

The fuel cell system according to claim 1 of the present invention includes a fuel gas supply means for supplying hydrocarbon fuel gas, a reforming water supply means for supplying water used for steam reforming, and the modified A vaporizer for vaporizing the reformed water from the quality water supply means; a reformer for steam reforming the fuel gas from the fuel gas supply means using the steam from the vaporizer; and the reformer A fuel cell module assembly composed of a plurality of fuel cell modules that generate power by oxidation and reduction of the reformed reformed fuel gas and oxidant, and the plurality of fuel cells to burn excess fuel gas that does not contribute to power generation A combustion chamber provided at the upper end or directly above each of the fuel cell modules,
The reformer has a plurality of reforming chamber portions disposed corresponding to the combustion chambers of the plurality of fuel cell modules, and combustion exhaust of the combustion chambers of the plurality of fuel cell modules. The corresponding reforming chamber is heated using gas,
The carburetor is disposed in a region of the fuel cell module assembly surrounded by the plurality of fuel cell modules, and is disposed from the combustion chamber of each of the plurality of fuel cell modules of the fuel cell module assembly. Combustion exhaust gas flows through the vaporizer, and reformed water from the reforming water supply means is vaporized using the combustion exhaust gas from the combustion chambers of each of the plurality of fuel cell modules in the vaporizer. And
Further, the fuel gas from the fuel gas supply means and the reforming steam from the vaporizer are mixed between the fuel gas supply means and the plurality of reforming chambers of the reformer . A mixing housing is provided, and further, the plurality of reformers of the reformer are disposed between the plurality of reforming chamber portions of the reformer and the plurality of fuel cell modules of the fuel cell module assembly. A second mixing housing is provided for mixing the reformed fuel gas that has been steam-reformed in the mass chamber;
The reforming steam and the fuel gas mixed in the first mixing housing are branched and supplied to the plurality of reforming chambers of the reformer, and the plurality of reformers of the reformer The reformed fuel gas that has undergone steam reforming in the reforming chamber is mixed in the second mixing housing, and then branched and fed to the plurality of fuel cell modules of the fuel cell module assembly. It is characterized by.

Further, in the fuel cell system according to claim 2 of the present invention, the carburetor is provided with an exhaust gas discharge passage through which combustion exhaust gas from each of the combustion chambers of the plurality of fuel cell modules flows. A combustion catalyst is provided in the exhaust gas discharge passage, and the reformed water is vaporized using the combustion exhaust gas flowing through the exhaust gas discharge passage.

In the fuel cell system according to claim 3 of the present invention, the vaporizer includes a vaporization housing that defines a vaporization chamber for vaporizing reformed water, and the vaporization housing functions as the first mixing housing. It is characterized by.

In the fuel cell system according to claim 4 of the present invention, the vaporizer includes a vaporization housing that defines a vaporization chamber for vaporizing reformed water, and the exhaust gas discharge passage is defined in the vaporization housing. A flow path member is mounted, the combustion catalyst is provided on an inner peripheral surface of the flow path member, and the flow path member is configured to be inserted and removed through an insertion opening provided in the vaporization housing . It is characterized by.

Further, in the fuel cell system according to claim 5 of the present invention, the fuel gas from the fuel gas supply means is supplied to the vaporizer, and the fuel gas is mixed with the reforming vapor vaporized by the vaporizer. In addition, a starting ignition means for starting the plurality of fuel cell modules is provided in association with the exhaust gas discharge flow path.

According to the fuel cell system of the first aspect of the present invention, the reformer is arranged corresponding to the combustion chamber provided at the upper end portion or immediately above each of the plurality of fuel cell modules of the fuel cell module assembly. A plurality of reforming chambers provided, and a first mixing housing is provided between the fuel gas supply means and the reformer chambers of the reformer, and the fuel gas from the fuel gas supply means is vaporized. The steam from the reactor is mixed in the first mixing housing, and after being mixed, it is branched and sent to a plurality of reforming chambers of the reformer. The mixing ratio and the supply amount of the fuel gas and steam to be made substantially uniform, whereby the steam reforming reaction similarly occurs in each reforming chamber, and reformed fuel gas having substantially the same components is generated. be able to. Further, since the second mixing housing is provided between the plurality of reforming chamber portions of the reformer and the plurality of fuel cell modules of the fuel cell module assembly, the plurality of reforming chamber portions of the reformer are provided with the second mixing housing. The reformed fuel gas that has been steam reformed after being mixed in the second mixing housing is branched and fed to each fuel cell module, whereby the reformed fuel that is fed to each fuel cell module The gas components and the supply amount can be supplied in a more uniform state. As a result, the actual fuel utilization rate in each fuel cell module is constant, and the desired power generation can be achieved with a relatively simple configuration and control. Output can be obtained stably.
Further, the combustion exhaust gas from the combustion chambers of the plurality of fuel cell modules in the fuel cell module assembly flows through the vaporizer, and the reformed water is vaporized using the combustion exhaust gas. The required water vapor can be vaporized using the heat of the combustion exhaust gas of these fuel cell modules. Further, since the carburetor is arranged in a region surrounded by the plurality of fuel cell modules of the fuel cell module assembly, the combustion exhaust gas from the plurality of fuel cell modules flows smoothly to the carburetor, and the carburetor is It becomes easy to keep at high temperature.

In the fuel cell system according to claim 2 of the present invention, the exhaust gas discharge passage is provided in the carburetor, and the combustion catalyst is provided in the exhaust gas discharge passage. The fuel gas remaining in the gas can be burned by this vaporizer and used for vaporizing reformed water.

According to the fuel cell system of the third aspect of the present invention, the vaporizing housing of the vaporizer functions as the first mixing housing. Therefore, the reforming vapor and fuel vaporized in the vaporizing chamber of the vaporizing housing The gas can be mixed and made uniform, and the configuration associated with the vaporizer and the first mixing housing can be simplified.

In the fuel cell system according to claim 4 of the present invention, since the combustion catalyst is provided on the inner peripheral surface of the flow path member of the carburetor, the combustion exhaust gas from the plurality of fuel cell modules The fuel gas remaining in the combustion exhaust gas can be burned while flowing in the flow path member. Further, since the flow path member is configured to be freely inserted and removed through the insertion opening provided in the vaporization housing , the flow path member can be easily replaced through the insertion opening when the combustion catalyst is deteriorated. .

Furthermore, according to the fuel cell system of the fifth aspect of the present invention, since the starting ignition means is provided in the exhaust gas discharge passage of the carburetor, the exhaust gas discharge passage of the carburetor at the time of startup. The starting ignition means ignites the fuel gas flowing through the fuel gas (the fuel cell module is not in operation, so the supplied fuel gas flows through the exhaust gas discharge passage), and the combustion heat of this ignition combustion is used. Thus, the vaporizer is heated to heat the fuel gas and the reformed water, and a plurality of fuel cell modules can be activated with a simple configuration in which one activation ignition means is provided. A general heater can be used as the starting ignition means, but a spark ignition device, a laser ignition device, or the like may be used.

The perspective view which shows the principal part of one Embodiment of the fuel cell system according to this invention. The rear view which shows the fuel cell system of FIG. The figure which shows the flow of the combustion exhaust gas in the fuel cell system of FIG. The perspective view which looked at the fuel cell system of FIG. 1 from diagonally upward. The side view which shows simply the vaporizer | carburetor in the fuel cell system of FIG. Sectional drawing by the VI-VI line in FIG. Sectional drawing by the VII-VII line in FIG. The top view which shows the other form of a vaporizer | carburetor. Sectional drawing by the IX-IX line in FIG. Sectional drawing by the XX line in FIG. The perspective view which shows the principal part of other embodiment of the fuel cell system according to this invention. Schematic which shows the 1st form of the fuel cell system considered based on a prior art. Schematic which shows the 2nd form of the fuel cell system considered based on a prior art.

  Hereinafter, an embodiment of a fuel cell system according to the present invention will be described with reference to the accompanying drawings. 1 and 2, the illustrated fuel cell system includes a fuel cell module assembly 4 including a plurality (four in the illustrated form) of fuel cell modules 2. The plurality of fuel cell modules 2 have substantially the same configuration, and one of them will be described below.

  The illustrated fuel cell module 2 (2 a, 2 b) includes two cell stacks 6 in which solid oxide cells are stacked, and these two cell stacks 6 are attached to the upper surface of the fuel header 8. In such a solid oxide cell, for example, yttria-doped zirconia is used as a solid electrolyte that conducts oxygen ions, and a fuel electrode for oxidizing the reformed fuel gas is provided on one side of the solid electrolyte. An air electrode for reducing oxygen in the air is provided on the side, and a cell stack 6 is configured by stacking a large number of such cells. In this embodiment, as will be described later, the reformed fuel gas fed to the fuel header 8 is fed to the fuel electrode side of a large number of cells of the pair of cell stacks 6 through the fuel header 8, and as an oxidizing material. The air flows through the periphery of the cell stack 6 of the fuel cell module 2 toward the fuel header 8 and is fed from the lower end of the cell stack 6 to the air electrode side.

  In this fuel cell system, a reformer 9 for reforming fuel gas is provided upstream of the fuel cell module assembly 4. In this embodiment, a pair of fuel cell modules 2a are disposed on the left side in FIGS. 1 and 2, and a pair of fuel cell modules 2b are disposed on the right side to face the fuel cell modules 2a. Has reforming chambers 10 (10a, 10b) arranged corresponding to these fuel cell modules 2a, 2b. A combustion chamber 12 is provided at the upper end portion or immediately above the fuel cell module 2 (2a, 2b), and the reforming chamber portion 10 (10a, 10b) of the reformer 9 is disposed above the combustion chamber 12. ing. Each reforming chamber 10 (10a, 10b) includes an elongated U-shaped chamber housing 14 (14a, 14b), and the chamber housing 14 is filled with a reforming catalyst (not shown).

  Referring also to FIG. 4, in this embodiment, in the left reforming chamber portion 10a, the chamber housing 14a includes a first chamber portion 16a located on the inner side, a second chamber portion 16b located on the outer side, and an outer side. A connection chamber portion 16c for connecting the first and second chamber portions 16a and 16b is provided at the end portion (the left end portion in FIGS. 1 and 2). The first chamber portion 16a of the reforming chamber portion 10a is disposed above the cell stack 6 inside the fuel cell module 2a, heated by the combustion exhaust gas from the combustion chamber 18 of the inner cell stack 6, and The second chamber portion 16 b is disposed above the outer cell stack 6 and is heated by the combustion exhaust gas from the combustion chamber 20 of the outer cell stack 6.

  Further, in the right reforming chamber portion 10b, the chamber housing 14b includes a first chamber portion 22a positioned on the inner side, a second chamber portion 22b positioned on the outer side, and an outer end portion (in FIGS. 1 and 2). In the right end portion, a connection chamber portion 22c for connecting the first and second chamber portions 22a and 22b is provided. The first chamber portion 22a of the reforming chamber portion 10a is disposed above the cell stack 6 inside the fuel cell module 2b, heated by the combustion exhaust gas from the combustion chamber 18 of the inner cell stack 6, and The second chamber portion 22 b is disposed above the outer cell stack 6 and is heated by the combustion exhaust gas from the combustion chamber 20 of the outer cell stack 6.

  A vaporizer 24 for vaporizing the reforming water is disposed on the upstream side of the reformer 9. In this embodiment, the carburetor 24 is disposed in a central region (a lateral central region in FIGS. 1 and 2) surrounded by the left pair of fuel cell modules 2a and the right pair of fuel cell modules 2b. With this configuration, the heat generated in the plurality of fuel cell modules 2 (2a, 2b) can be used for vaporizing the reforming water, and the vaporizer 24 can be kept at a high temperature.

  Hydrocarbon fuel gas (for example, city gas, LP gas, etc.) is used as the fuel gas, and hydrocarbon fuel gas from the fuel gas supply source 26 (see FIG. 5) (for example, buried pipe, gas tank, etc.) is used as fuel. It is supplied to the vaporizer 24 through the gas supply line 28 (if necessary, it is supplied to the vaporizer 24 after being desulfurized). The fuel gas supply line 28 is provided with a fuel gas pump (not shown) for supplying the fuel gas from the fuel gas supply source 26 to the carburetor 24 through the fuel gas supply line 28. The fuel gas supply line 30 and the fuel gas pump constitute fuel gas supply means 30 (see FIG. 5) for supplying fuel gas.

  Further, reforming water (for example, pure water) from a reforming water supply source 32 (see FIG. 5) (for example, a water tank or the like) is supplied to the vaporizer 24 via the reforming water supply line 34. The reforming water supply line 34 is provided with a water pump (not shown) for supplying the reforming water from the reforming water supply source 32 through the reforming water supply line 34 to the vaporizer 24. The supply source 32, the reforming water supply line 34, and the water pump constitute the reforming water supply means 36 (see FIG. 5) for supplying the reforming water.

  Next, the illustrated vaporizer 24 will be described with reference to FIGS. 1 to 7, mainly FIGS. 5 to 7. The vaporizer 24 includes a vaporization housing 40 that defines a vaporization chamber 38 that vaporizes reformed water, and a device housing 42 is provided so as to surround the vaporization housing 40, and between the device housing 42 and the vaporization housing 40. An exhaust gas flow path 44 is defined. The fuel gas supply line 28 and the reforming water supply line 34 extend into the vaporization chamber 38 through the apparatus housing 42, the exhaust gas passage 44 and the vaporization housing 40.

  Specifically, a double tube member 46 composed of an inner tube (not shown) and an outer tube 45 arranged concentrically is used, and the double tube member 46 is composed of an apparatus housing 42 and a vaporization housing 40. The vaporization chamber 38 extends through the vaporization housing 40 and extends downward in the vaporization housing 40 to the bottom thereof. The inner space of the double pipe member 46 (the space defined inside the inner tube) functions as the reforming water supply line 34, and reforming water is supplied to the vaporizing chamber 38 through the inner space, and the outer side thereof. The space (the annular space defined between the inner tube and the outer tube 45) functions as the fuel gas supply line 28, and the fuel gas is supplied to the vaporizing chamber 38 through the outer space.

  Inflow openings 48 (48a, 48b) (see FIG. 7) at the upper ends of both side surfaces of the device housing 42 (the side surfaces in the left-right direction in FIGS. 1 and 2 and facing the left and right fuel cell modules 2a, 2b). ) Is provided. The inflow opening 48 is elongated in the front-rear direction (the direction from the lower left to the upper right in FIG. 1, the direction perpendicular to the paper surface in FIG. 2), and one inflow opening 48a is provided between the pair of fuel cell modules 2a on one side, The inflow opening 48b is provided between the pair of fuel cell modules 2b on the other side. These inflow openings 48 (48a, 48b) are provided above the reforming chamber portions 10a, 10b of the reformer 9, and thus configured, the combustion chambers 18 of the plurality of fuel cell modules 2a, 2b. , 20 flows around the reforming chambers 10a, 10b of the reformer 9, and then flows into the exhaust gas flow path 44 of the carburetor 24 through the inflow openings 48 (48a, 48b). Become.

  In addition, a cylindrical flow path member 50 is disposed at a substantially central portion of the vaporizing chamber 38 of the vaporizing housing 40. The lower end portion of the flow path member 50 is communicated with the exhaust gas flow path 44 through the vaporization chamber 38, that is, through the bottom wall of the vaporization housing 40, and defines an exhaust gas discharge flow path 52 that discharges combustion exhaust gas. Since it is configured in this manner, the combustion exhaust gas that flows from the combustion chambers 18 and 20 of the pair of fuel cell modules 2a on one side to the periphery of the reforming chamber portion 10a of the reformer 9 is Flows into the exhaust gas discharge passage 52 in the device housing 42 through the inflow opening 48a of the fuel cell module 2 and from the combustion chambers 18 and 20 of the other pair of fuel cell modules 2b around the reforming chamber portion 10b of the reformer 9. The flowing combustion exhaust gas flows into the exhaust gas discharge passage 52 in the device housing 42 through the inflow opening 48 b on the other side surface of the device housing 42. The combustion exhaust gas that has flowed in this way flows down the exhaust gas passage 44 and then flows through the exhaust gas discharge passage 52 (in the passage member 50), as indicated by the arrow 54 (see FIGS. 5 and 7). Is discharged upward.

  In the vaporizer 24, the vaporization housing 40 functions as a first mixing housing that mixes the fuel gas from the fuel gas supply unit 30 and the water vapor obtained by vaporizing the reforming water from the reforming water supply unit 36. That is, in the carburetor 24, heat from the combustion exhaust gas flowing through the exhaust gas passage 44 and the exhaust gas discharge passage 52 acts on the vaporization chamber 38, and the heat is supplied from the reforming water supply means 36 using the heat. As the reformed water is vaporized, the fuel gas from the fuel gas supply means 30 is heated, and the water vapor and the fuel gas are uniformly mixed in the vaporization chamber 38.

  The vaporizer 24 is provided with outflow portions 56 (56a, 56b) corresponding to the reforming chamber portions 10 (10a, 10b) of the reformer 9. An outflow portion 56a is provided corresponding to the left fuel cell module 2a, and one end portion of the outflow portion 56a communicates with the inside of the vaporization chamber 38 through the device housing 42, the exhaust gas passage 44 and the vaporization housing 40. These other end portions are connected to the first chamber portion 16 a of the reforming chamber portion 10 a corresponding to the reformer 9. Also, an outflow portion 56b is provided corresponding to the right fuel cell module 2b, and one end portion of the outflow portion 5ba passes through the apparatus housing 42, the exhaust gas passage 44 and the vaporization housing 40 and enters the vaporization chamber 38. These other ends are connected to the first chamber portion 22 a of the reforming chamber portion 10 b corresponding to the reformer 9.

  With this configuration, the fuel gas and water vapor uniformly mixed in the vaporizing chamber 38 of the vaporizing housing 40 (functioning as the first mixing housing) are branched through the outflow portions 56a and 56b to be reformer 9. To the reforming chambers 10a and 10b. Therefore, the reformed chambers 10a and 10b of the reformer 9 are supplied with a mixed gas having substantially the same mixing ratio of the fuel gas and the water vapor, and the feed amount of the mixed gas is substantially equal. Steam reforming in the reforming chambers 10a and 10b is performed under substantially the same conditions. In order to make the amount of the mixed gas fed to each reforming chamber 10 (10a, 10b) uniform, these outflow portions 56 (56a, 56b) are symmetrical in the vaporizing chamber 38 in the front-rear direction and the left-right direction. It is preferable to arrange so that.

  In the vaporizer 24, it is preferable to provide a combustion catalyst 58 on the inner peripheral surface of the flow path member 50. The combustion exhaust gas flowing into the exhaust gas flow path 44 of the carburetor 24 contains unburned fuel gas and air (containing oxygen). By providing the combustion catalyst 58 in this way, combustion is performed. The fuel gas remaining in the exhaust gas is burned, and this combustion heat can be used for vaporizing the reforming water. The combustion catalyst 58 may be provided on the inner surface of the device housing 42 and / or the outer surface of the vaporization housing 40.

  An air heat exchanger 60 (see FIG. 3) is disposed above the carburetor 24, and the combustion exhaust gas discharged through the flow path member 50 of the carburetor 24 as indicated by an arrow 54 is used for this heat exchange for air. It is discharged through the vessel 60 as shown by arrow 62. On the other hand, the air supplied to each fuel cell module 2 (2a, 2b) of the fuel cell module assembly 4 is supplied through the air heat exchanger 60, and in this heat exchanger 60, combustion exhaust gas, air, Heat exchange is performed between the two, and air heated by this heat exchange is supplied to the air electrode side of each fuel cell module 2 (2a, 2b).

  1 to 4, in this fuel cell system, the reformer 9 (that is, the reforming chamber portion 10) and the fuel cell module assembly 4 (that is, a plurality of fuel cell modules 2) are further connected. A second mixing housing 64 is provided therebetween. The second mixing housing 64 is disposed on the lower side of the carburetor 24 (that is, the central region surrounded by the left fuel cell module 2a and the right fuel cell module 2b). The heat is transferred to the second mixing housing 64.

  In this embodiment, the second mixing housing 64 is elongated in the front-rear direction (the direction from the lower left to the upper right in FIG. 1, the direction perpendicular to the paper in FIG. 2, the vertical direction in FIG. 4), and the front fuel cell module 2 (2a, 2a, 2b) extends from the front end of the fuel cell module 2 (2a, 2b) on the rear side.

  Regarding the front fuel cell modules 2a and 2b facing each other with the vaporizer 24 and the second mixing housing 64 in between, the second reforming chamber portion 10a on the left side of the reforming chamber portions 10a and 10b on the left side of the reformer 9 is provided. The outflow connection portion 66a is provided in the chamber portion 16b (outside chamber portion), and the outflow connection portion 66b is provided in the second chamber portion 22b (outside chamber portion) of the right reforming chamber portion 10b. These outflow connection portions 66a and 66b are connected to the front portion of the second mixing housing 64 via a T-shaped connecting connection pipe 68 (see FIGS. 1 and 4). An outflow connection 66a is provided in the second chamber 16b of the left reforming chamber 10a among the reforming chambers 10a and 10b on the rear side of the reformer 9, and the right reforming chamber 10b The outflow connection portion 66b is provided in the second chamber portion 22b, and the outflow connection portions 66a and 66b are connected to the rear portion of the second mixing housing 64 via a T-shaped connecting connection pipe 70 (see FIG. 2).

  Further, connecting pipes 72 are provided at the four corners of the second mixing housing 64, and one of the front connecting pipes 72 of the second mixing housing 64 is at the front right corner of the fuel header 8 of the left fuel cell module 2a. The other of the front connection pipes 72 is connected to the front left corner of the fuel header 8 of the right fuel cell module 2b (see FIGS. 1 and 4). In addition, one of the rear connection pipes 72 of the second mixing housing 64 is connected to the rear right corner of the fuel header 8 of the left fuel cell module 2a, and the other of the rear connection pipes 72 is connected to the right fuel cell. It is connected to the rear left corner of the fuel header 8 of the module 2b (see FIG. 2).

  Since it is configured in this way, the reformed fuel gas that has been steam reformed in the reforming chambers 10a and 10b on the front side of the reformer 9 passes through the outflow connection parts 66a and 66b and the connecting connection pipe 68. The reformed fuel gas fed into the front part of the two mixing housing 64 and steam reformed in the reforming chambers 10a, 10b on the rear side is supplied through the outflow connection parts 66a, 66b and the connecting connection pipe 70. The reformed fuel gas fed into the rear portion of the two mixing housing 64 and thus flowing in is mixed uniformly in the second mixing housing 64. Even if the composition of the reformed fuel gas due to the steam reforming reaction in the reforming chambers 10a and 10b varies somewhat, the reformed fuel gas composition is mixed in the second mixing housing 64. Can be made uniform. Then, the reformed fuel gas that has become uniform in the second mixing housing 64 is supplied to the fuel header 8 of the corresponding fuel cell module 2 (2a, 2b) via the connection pipe 72. Therefore, the reformed fuel gas having a uniform composition is fed to the cell stack 6 of each fuel cell module 2a, 2b of the fuel cell module assembly 4 via the fuel header 8, and the amount of the fuel is almost equal. As a result, the electrochemical reaction in the cell stack 6 of each fuel cell module 2a, 2b is performed under substantially the same conditions, and power generation in each cell stack 6 can be performed stably. In order to make the supply amount of the reformed fuel gas to each fuel cell module 2 (2a, 2b) (in this embodiment, each fuel header 8) more uniform, these connection pipes 72 are connected to the second mixing housing 64. It is preferable to provide it symmetrically in the front-rear direction and the left-right direction.

  In this fuel cell system, the starting ignition means (not shown) is provided with the exhaust gas discharge passage 52 of the carburetor 24 (when the combustion catalyst 58 is provided in the exhaust gas discharge passage 52, the combustion catalyst 58 is arranged. It is provided in relation to the installation site). In general, the starting ignition means is provided at the upper end of the stack 6 of the fuel cell modules 2a and 2b. In such a configuration, one ignition means is provided for each cell stack 6 of each fuel cell module 2a and 2b. It is necessary to provide driving ignition means. In contrast, if the exhaust gas discharge passage 52 (or the location where the combustion catalyst 58 is disposed) of the carburetor 24 is provided, all the fuel cell modules 2a, 2b are provided with a single starting ignition means. Can be activated, and the configuration related to the ignition means for activation can be simplified.

  In this fuel cell system, the fuel gas from the fuel gas supply means 30 and the reformed water from the reformed water supply means 36 pass through the double pipe member 46 into the vaporization housing 40 (first mixing housing) of the vaporizer 24. Be sent. Combustion exhaust gas flowing from the fuel cell modules 2a and 2b of the fuel cell module assembly 4 around the reforming chambers 10a and 10b of the reformer 9 flows in from the inflow openings 48a and 48b of the carburetor 24. While flowing through the exhaust gas flow path 44 and the exhaust gas discharge flow path 52, the heat exchange with the combustion exhaust gas causes the reformed water to evaporate into steam and the fuel gas to be heated. At this time, since the vaporizer 24 is composed of one chamber, the fuel gas and the generated water vapor become a mixed gas in a uniform state.

  The mixed gas in the vaporization housing 40 (first mixing housing) flows into the corresponding reforming chamber 10 of the reformer 9 through the outflow portions 56a and 56b, and flows through the reforming chambers 10a and 10b. Steam reforming is performed using the heat of the fuel exhaust gas in the fuel chambers 18 and 20 of the corresponding fuel cell modules 2a and 2b. The reformed fuel gas steam-reformed in the reforming chambers 10a and 10b of the reformer 9 is supplied to the second mixing housing 64 via the connection pipes 66a and 66b and the connection connection pipes 68 and 70. The mixed gas is mixed in the second mixing housing 64 to be in a uniform state, and the uniform reformed fuel gas is supplied to the fuel header 8 of the fuel cell module 2 (2a, 2b) through the connection pipe 72. With such a relatively simple configuration, the steam reforming reaction in the reforming chambers 10a and 10b of the reformer 9 can be maintained under substantially the same conditions, and each fuel of the fuel cell module assembly 4 can be maintained. The fuel cell reactions in the battery modules 2a and 2b can also be maintained under substantially the same conditions, and the actual fuel utilization rate can also be maintained constant.

  8-10 has shown the other form of the vaporizer | carburetor. In this form of vaporizer, the vaporization chamber and the first mixing housing are configured separately. In addition, the same reference number is attached | subjected to the member substantially the same as embodiment mentioned above, and the description is abbreviate | omitted.

  8 to 10, the carburetor 24A of this modification includes three vaporization housings 38A, 38B, and 38C that are spaced apart in the left-right direction in FIGS. 8 and 10, and these three vaporization housings. 38A, 38B, and 38C each define a vaporization chamber. An apparatus housing 42A is provided so as to surround these vaporization housings 38A, 38B, 38C, and inflow openings 48A, 48B into which combustion exhaust gas flows are provided at the upper end of the apparatus housing 42A. An exhaust gas passage 44A is defined between the apparatus housing 42A and the vaporization housings 38A, 38B, 38C, and the combustion exhaust gas flowing in from the inflow openings 48A, 48B is discharged from the outflow opening 73 through the exhaust gas passage 44A. Is done.

  Fuel gas from a fuel gas supply means (not shown) is fed to the distribution header 74 through the fuel gas supply line 28A, and reformed water from the reformed water supply means 36 passes through the reformed water supply line 34. It is fed to the distribution header 74, distributed by the distribution header 74 to the three branch double tubes 46A, 46C, 46C and fed into the corresponding vaporizing housings 38A, 38B, 38C. The branch double pipe 46A (46B, 46C) has an inner pipe 76 and an outer pipe 78, and the reformed water distributed by the distribution header 74 is supplied to the inner pipe 76 of the branch double pipe 46A (46B, 46C). The fuel gas fed through the inner space and distributed by the distribution header 74 is fed through the annular space between the inner pipe 76 and the outer pipe 78 of the branch double pipe 46A (46B, 46C).

  The branch double pipe 46A (or 46B, 46C) extends above the apparatus housing 42A to the vaporizing housing 38A (or 38B, 38C), and connects the apparatus housing 42A, the exhaust gas passage 44A and the vaporizing housing 38A (or 33B, 38C). It penetrates and extends below the vaporization chamber (not shown). One end side (the upper end side in FIG. 8) of the three vaporization housings 38A, 38B, and 38C is provided with a vaporization mixing housing 76 (constituting the first mixing housing), and the upper end portions of the vaporization housings 38A, 38B, and 38C are The water vapor and the heated fuel gas that are communicated with the vaporizing housing 76 and vaporized in the vaporizing housings 38A, 38B, and 38C are mixed in the vaporizing and mixing housing 76 to be in a uniform state. The mixed gas thus uniformly mixed is fed from the vaporizing and mixing housing 76 to a reforming chamber (not shown) of the reformer as indicated by an arrow 77.

  When a plurality of vaporization housings 38A, 38B, and 38C are provided in this manner, the vaporization mixing housing 76 (that is, the first mixing housing) is provided on the downstream side thereof, and the plurality of vaporization housings 38A, 38B, and 38C are provided. By mixing the water vapor and the fuel gas, the composition of the mixed gas fed to each reforming chamber of the reformer disposed on the downstream side can be made uniform. Therefore, a gas mixture with substantially the same mixing ratio of the fuel gas and steam is fed to each reforming chamber of the reformer, and the feeding amount is also almost equal. As a result, as described above, The steam reforming in each reforming chamber is performed under substantially the same conditions.

  Such a fuel cell system can be advantageously applied to a system of several kW class by using a plurality of fuel cell modules having a power generation output of several hundred to 1000 W class, and a fuel cell module of several kW class can be applied. It can be applied to a system of 10 kW or more.

As mentioned above, although the embodiment of the fuel cell module assembly according to the present invention has been described, the present invention is not limited to such an embodiment, and various changes or modifications can be made without departing from the scope of the present invention. ,
For example, in the illustrated embodiment, two fuel cell modules are arranged on one side, and two fuel cell modules are arranged on the other side so as to face the two fuel cell modules. One or three or more fuel cell modules may be arranged, and for example, one or three or more fuel cell modules may be arranged on the other side. It is not necessary to arrange them facing each other).

  In the illustrated embodiment, the carburetor is disposed in a region surrounded by the fuel cell module on one side and the fuel cell module on the other side. However, the present invention is not limited to such a configuration, and a plurality of fuel cell modules are provided. May be arranged radially at intervals in the circumferential direction, and a carburetor may be arranged in a central region surrounded by these fuel cell modules.

  In addition, such a fuel cell system can be configured as shown in FIG. 11 in relation to the flow path member 50 of the vaporizer. In FIG. 11, in this embodiment, an insertion opening (not shown) is provided in the upper wall 80 of the device housing 42B of the vaporizer 24B corresponding to the arrangement position of the flow path member 50, and a closing member is provided in the insertion opening. 82 is removably attached. In relation to this, the flow path member 50 is detachably attached to the vaporizing housing 40 (see FIG. 5), for example. The closing member 82 may be attached to the vaporizing housing 40 so as to be freely opened and closed.

  If comprised in this way, an insertion opening (not shown) can be open | released, for example by removing the obstruction | occlusion member 82, and a vaporization housing is inserted by inserting the flow-path member 50 through this insertion opening in such an open state. 40, and can be removed from the vaporization housing 40 by being pulled out through the insertion opening, and the flow path member 50 can be easily replaced when the combustion catalyst is deteriorated.

2, 2a, 2b Fuel cell module 4 Fuel cell module assembly 6 Cell stack 8 Fuel header 9 Reformer 10, 10a, 10b Reform chamber 24, 24A, 24B Vaporizer 30 Fuel gas supply means 36 Reform water supply 36 Means 40 Vaporization housing (first mixing housing)
50 Channel member 58 Fuel catalyst 64 Second mixing housing 76 Vaporization mixing housing (first mixing housing)

Claims (5)

Fuel gas supply means for supplying hydrocarbon fuel gas, reformed water supply means for supplying water used for steam reforming, and a vaporizer for vaporizing the reformed water from the reformed water supply means And a reformer for steam reforming the fuel gas from the fuel gas supply means using the steam from the vaporizer, oxidation of the reformed fuel gas and the oxidizing material reformed by the reformer, and A fuel cell module assembly composed of a plurality of fuel cell modules that generate power by reduction, and an upper end portion or a directly upper portion of each of the plurality of fuel cell modules for burning surplus fuel gas that does not contribute to power generation And a combustion chamber,
The reformer has a plurality of reforming chamber portions disposed corresponding to the combustion chambers of the plurality of fuel cell modules, and combustion exhaust of the combustion chambers of the plurality of fuel cell modules. The corresponding reforming chamber is heated using gas,
The carburetor is disposed in a region of the fuel cell module assembly surrounded by the plurality of fuel cell modules, and is disposed from the combustion chamber of each of the plurality of fuel cell modules of the fuel cell module assembly. Combustion exhaust gas flows through the vaporizer, and reformed water from the reforming water supply means is vaporized using the combustion exhaust gas from the combustion chambers of each of the plurality of fuel cell modules in the vaporizer. And
Further, the fuel gas from the fuel gas supply means and the reforming steam from the vaporizer are mixed between the fuel gas supply means and the plurality of reforming chambers of the reformer . A mixing housing is provided, and further, the plurality of reformers of the reformer are disposed between the plurality of reforming chamber portions of the reformer and the plurality of fuel cell modules of the fuel cell module assembly. A second mixing housing is provided for mixing the reformed fuel gas that has been steam-reformed in the mass chamber;
The reforming steam and the fuel gas mixed in the first mixing housing are branched and supplied to the plurality of reforming chambers of the reformer, and the plurality of reformers of the reformer The reformed fuel gas that has undergone steam reforming in the reforming chamber is mixed in the second mixing housing, and then branched and fed to the plurality of fuel cell modules of the fuel cell module assembly. A fuel cell system. The carburetor is provided with an exhaust gas exhaust passage through which combustion exhaust gas from the combustion chamber of each of the plurality of fuel cell modules flows, and a combustion catalyst is provided in the exhaust gas exhaust passage, and the exhaust gas The fuel cell system according to claim 1 , wherein the reformed water is vaporized using combustion exhaust gas flowing through the discharge passage. The fuel cell system according to claim 2 , wherein the vaporizer includes a vaporization housing that defines a vaporization chamber that vaporizes reformed water, and the vaporization housing functions as the first mixing housing. The vaporizer includes a vaporization housing that defines a vaporization chamber that vaporizes reformed water, and a flow path member that defines the exhaust gas discharge flow path is mounted in the vaporization housing, and an inner peripheral surface of the flow path member The fuel cell system according to claim 2 , wherein the combustion catalyst is provided, and the flow path member is configured to be freely inserted and removed through an insertion opening provided in the vaporization housing . The fuel gas from the fuel gas supply means is supplied to the vaporizer, the fuel gas is mixed with the reforming vapor vaporized in the vaporizer, and the plurality of the exhaust gas discharge passages are associated with the plurality of The fuel cell system according to claim 2 , further comprising start ignition means for starting the fuel cell module.

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