JP2014049305A - Fuel cell device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel cell device which allows for suppression of deterioration at the connection part of a reformer and piping, by allowing relative displacement due to difference of thermal expansion between a support member for supporting the reformer and a modified gas supply pipe and a water supply pipe.SOLUTION: A fuel cell module 2 constituting a fuel cell device includes a reformer 20 located above a fuel cell stack 12, while fixing one and the other ends to support members 30a, 30b, respectively, and modifying the modified gas supplied to fuel gas, a modified gas supply pipe 60 connected with one end of the reformer 20 and supplying the modified gas thereto, and a water supply pipe 62 connected with one end of the reformer 20 and supplying water thereto. At least any one of the modified gas supply pipe 60 and water supply pipe 62 includes stretching regions 35a, 35b for allowing relative displacement due to difference of thermal expansion between at least any one of the modified gas supply pipe 60 and water supply pipe 62 and the support members 30a, 30b.

Description

  The present invention relates to a fuel cell device that generates power using fuel gas and oxidant gas.

  The fuel cell device disclosed in Patent Literature 1 incorporates a reformer that reforms a gas to be reformed such as city gas into fuel gas. The reformer is disposed above a fuel cell stack that is an assembly of a plurality of fuel cells arranged at a predetermined interval. The fuel cell stack generates power using fuel gas and oxidant gas rising from the lower end to the upper end of the fuel cell stack. The fuel gas and oxidant gas used in the fuel cell stack are combusted above the fuel cell stack, the reformer is heated by the combustion heat, and reforming of the reformed gas into the fuel gas proceeds. .

  A reformer disclosed in Patent Document 1 is connected to one end of a reformer and supplies a reformed gas supply pipe that supplies a reformed gas to the reformer and a water supply pipe that supplies water to the reformer And is supported by a fuel gas supply pipe that is connected to the other end of the reformer and causes the fuel gas to flow out of the reformer.

JP 2011-96577 A

  The reformer is heavy because it is a metal container filled with a reforming catalyst. In a fuel cell device, in particular, a solid oxide fuel cell device, the operating temperature in steady operation becomes a high temperature of about 700 ° C. Therefore, the temperature change from the start to the steady operation and the temperature change from the steady operation to the stop are It will be extremely large. In such a large temperature change, if a heavy reformer is supported by three supply pipes, each supply pipe and the connection part between each supply pipe and the reformer are expanded and expanded under a high load. The contraction is repeated, and there is a concern that the progress of metal fatigue and thermal fatigue in each supply pipe and connection part is promoted and the long-term use cannot be endured.

  Accordingly, the present invention has been made in view of such circumstances, and suppresses deterioration in each supply pipe connected to the reformer and deterioration in a connection portion between the reformer and each supply pipe, and the use for a long time. An object of the present invention is to provide a fuel cell device that can withstand this.

  In order to achieve the above object, the present inventors newly provided a support member for supporting the reformer separately from each supply pipe, reducing the weight of the reformer acting on each supply pipe, It was considered to suppress a large mechanical load on each supply pipe and connection part. If the support member is separately provided in this way, the weight of the reformer does not act on each supply pipe as it is. However, the difference in thermal expansion between the support member and each supply pipe exists more than expected, and stress is applied to the connection portion between each supply pipe or reformer and each supply pipe due to the difference in thermal expansion. Therefore, the present inventors have found that a new problem occurs that the deterioration of those portions proceeds. The present invention has been made based on such knowledge.

  In order to solve this new problem, a fuel cell device according to the present invention is a fuel cell device that generates power using fuel gas and oxidant gas, and has a fuel gas passage for passing the fuel gas therein. A fuel cell stack having a plurality of formed fuel cells and a fuel cell stack disposed above the fuel cell stack and passing the gas to be reformed and water from one end to the other end to fuel the gas to be reformed A reformer for reforming into a gas; a first supply pipe connected to one end of the reformer; supplying a reformed gas to the reformer; connected to one end of the reformer; A second supply pipe that supplies water to the reformer; and a third supply pipe that is connected to the other end of the reformer and supplies fuel gas from the reformer to the fuel gas flow path. The plurality of fuel cells so that the fuel cell stack has a rectangular parallelepiped shape as a whole. Cells is erected along each other. In the present invention, the first support member is disposed so as to face one side surface of the fuel cell stack along the standing direction of the fuel cell and the other side surface opposite to the one side surface. And a second support member, wherein the first support member supports the one end side of the reformer, and the second support member supports the other end side of the reformer. At least one of the first supply pipe and the second supply pipe includes a thermal expansion amount of the first support member and the second support member and at least one of the first supply pipe and the second supply pipe. In order to allow relative displacement based on the difference from the amount of thermal expansion, a stretchable region is formed that can be stretched along the extending direction of at least one of the first supply pipe and the second supply pipe.

  As described above, according to the present invention, the first support member and the second support member for supporting the reformer are provided with one side surface of the fuel cell stack along the standing direction of the fuel cell, and one side surface thereof. Is disposed so as to face the other side of the opposite side, and the reformer disposed above the fuel cell stack is securely supported, so that the weight of the reformer can be reduced. It can be supported by two support members. Since the first support member and the second support member are arranged on the sides of the fuel cell stack, they thermally expand as the temperature of the region including the fuel cell stack increases. On the other hand, since the temperature of the first supply pipe that supplies the gas to be reformed before reforming and the second supply pipe that supplies water are relatively low, the thermal expansion amount is different. Arise. Therefore, in the present invention, the thermal expansion amount of the first support member and the second support member and the thermal expansion amount of at least one of the first supply pipe and the second supply tube are provided on at least one of the first supply pipe and the second supply pipe. In order to allow relative displacement based on the difference between the first supply pipe and the second supply pipe, an expansion / contraction region is provided that can expand and contract along the extending direction of at least one of the first supply pipe and the second supply pipe. Therefore, even if a difference in thermal expansion occurs between the first support member and the second support member that support the reformer and the first supply pipe and the second supply pipe, the expansion / contraction region is in the direction in which the supply pipe extends. By absorbing the relative displacement due to the difference, the stress applied to the connecting portion between the reformer and the first supply pipe and the second supply pipe can be suppressed. An endurable fuel cell device can be provided.

  In the fuel cell device according to the present invention, the expansion / contraction region includes a first expansion / contraction region provided in the first supply pipe and a second expansion / contraction region provided in the second supply pipe. Since the first expansion region and the second expansion region absorb the difference between the thermal expansion amount of the first supply pipe and the thermal expansion amount of the second supply pipe, the mutual expansion amount along the extending direction is different. It is also preferable to be configured as described above.

  Since the temperature of water is lower than the temperature of the gas to be reformed, the heat that the water takes from the second supply pipe is larger than the heat that the gas to be reformed takes from the first supply pipe. Therefore, even if the environmental temperature surrounding the first supply pipe and the second supply pipe is the same, the temperature of the second supply pipe is lower than the temperature of the first supply pipe. Therefore, the amount of thermal expansion of the second supply pipe is smaller than the amount of thermal expansion of the first supply pipe, and the stress applied to the connection portion between the second supply pipe and the second supply pipe and the reformer may be excessive. is there. Therefore, in this preferred embodiment, the first supply pipe is provided with the first expansion / contraction area, and the second supply pipe is provided with the second expansion / contraction area so that the expansion / contraction amounts in the extending direction are different. In this way, by providing the first expansion region and the second expansion region with different expansion amounts, the difference between the thermal expansion amount of the first supply pipe and the thermal expansion amount of the second supply pipe is absorbed, and the second supply pipe or The stress applied to the connection portion between the second supply pipe and the reformer can be prevented from becoming excessive.

  Further, in the fuel cell device according to the present invention, the expansion / contraction region is the first support member, the second support member, the first supply pipe, and the second supply pipe even in a lateral direction orthogonal to the extending direction. It is also preferable to be configured to allow relative displacement with at least one of the above.

  In the present invention, the first support member supports one end side of the reformer, and the second support member supports the other end side of the reformer. The reformer has a structure in which the gas to be reformed and water are supplied from one end side and the fuel gas after the reforming reaction is taken out from the other end side. Accordingly, since the high temperature fuel gas after the reforming reaction passes through the third supply pipe for taking out the fuel gas from the other end side, the second support member arranged in the vicinity thereof is also compared with the first support member. And become hot. Therefore, the amount of thermal expansion of the second support member is larger than the amount of thermal expansion of the first support member, and as a result, the reformer may tilt toward the first support member. When the first support member side is lowered with the second support member side as a fulcrum in this way, a force is applied to the first supply pipe and the second supply pipe so as to bend in the lateral direction. Therefore, in this preferable aspect, the expansion / contraction region is configured to allow relative displacement between the first support member and the second support member and at least one of the first supply pipe and the second supply pipe even in the lateral direction. Thus, even when such a bending force is applied, the stress applied to the connecting portion between the reformer and the first supply pipe and the second supply pipe can be suppressed.

  In the fuel cell device according to the present invention, the vaporizer is disposed adjacent to the reformer and vaporizes water supplied from the second supply pipe into water vapor before being supplied to the reformer. It is also preferable that the evaporating chamber and the reformer are supported by the first support member and the second support member, and the evaporating chamber is disposed closer to the stretchable region than the reformer.

  While the reformer in the present invention is filled with a reforming catalyst, the inside of the evaporation chamber is configured to be a cavity. Therefore, the reformer is relatively heavy and the evaporation chamber is a light part. Therefore, in this preferred embodiment, by placing a relatively light evaporation chamber on the expansion / contraction region side, even if there is a difference in thermal expansion amount between the first support member and the second support member, an excessive burden is imposed on the expansion / contraction region side. Is reduced.

  In the fuel cell device according to the present invention, it is also preferable that the expansion / contraction region is provided at a position corresponding to a height at which the plurality of fuel cells are arranged.

  The combustion gas in which the remaining fuel gas and air combust at the upper end of the fuel cell goes upward from the upper end of the fuel cell, so that the combustion heat accompanying the combustion gas also propagates upward. Therefore, in this preferred embodiment, by providing the expansion / contraction region at a position corresponding to the height at which the combustion battery cell is disposed, it is possible to suppress the wraparound of the combustion heat to the expansion / contraction region. Therefore, the stress applied to the connecting portion between the reformer and the pipe can be more reliably suppressed without reducing the expansion / contraction performance of the expansion / contraction region.

  In the fuel cell device according to the present invention, it is also preferable that the first support member is formed so as to be interposed between the stretchable region and the fuel cell.

  In this preferred embodiment, since the first support member is interposed so as not to directly transfer the heat propagating from the fuel cell side to the expansion / contraction region, the reformer can be more reliably produced without reducing the expansion / contraction performance of the expansion / contraction region. The stress applied to the connecting portion between the pipe and the pipe can be suppressed.

  According to the present invention, it is possible to provide a fuel cell device capable of withstanding long-term use by suppressing deterioration in each supply pipe connected to the reformer and deterioration in a connection portion between the reformer and each supply pipe. Can do.

It is a perspective view which shows the external appearance of the fuel cell module of the fuel cell apparatus which concerns on one Embodiment of this invention. It is sectional drawing of the fuel cell module of FIG. It is a side view which shows the state which removed some casings of FIG. It is a perspective view which shows the state which removed the casing and heat exchanger of FIG. It is a side view which shows the state which removed the casing and heat exchanger of FIG. It is a perspective view which shows the structure of a spacer and a supporting member roughly. FIG. 3 is a schematic diagram corresponding to FIG. 2, and is a schematic diagram illustrating flows of an oxidant gas and a combustion gas. FIG. 4 is a schematic diagram corresponding to FIG. 3, and is a schematic diagram illustrating flows of an oxidant gas and a combustion gas. It is a fragmentary sectional view showing a fuel cell unit. It is a perspective view which shows the structure of a fuel cell stack. It is a side view which shows the state which removed some casings of FIG. 1, Comprising: It is a figure which shows the state which the support member of the fuel cell apparatus expanded thermally. It is a figure which shows the expansion-contraction area | region of a fuel cell apparatus.

  Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. In order to facilitate understanding of the description, the same components are denoted by the same reference symbols in the drawings, and redundant description is omitted. FIG. 1 is a perspective view showing an appearance of a fuel cell module 2 of a fuel cell device according to an embodiment of the present invention. The fuel cell module 2 constitutes a part of a solid oxide fuel cell (SOFC) device. That is, the fuel cell device includes a fuel cell module 2 and an auxiliary unit (not shown).

  In FIG. 1, the height direction of the fuel cell module 2 is the y-axis direction. The x-axis and z-axis are defined along a plane orthogonal to the y-axis, the direction along the short direction (width direction) of the fuel cell module 2 is defined as the x-axis direction, and the longitudinal direction (long) of the fuel cell module 2 is defined. The direction along the vertical direction is the z-axis direction. The x-axis, y-axis, and z-axis described in FIG. 2 and thereafter are based on the x-axis, y-axis, and z-axis in FIG. Further, the direction along the negative direction of the z axis is the A direction, and the direction along the positive direction of the x axis is the B direction.

  The fuel cell module 2 includes a casing 56 that houses a fuel cell stack (details will be described later), and a heat exchanger 22 provided on the upper portion of the casing 56. The casing 56 is formed in a rectangular parallelepiped shape, for example. The heat exchanger 22 is disposed on the upper surface of the casing 56. A fuel cell stack, which will be described later, is disposed in the casing 56. A reformed gas supply pipe 60 (first supply pipe) and a water supply pipe 62 (second supply pipe) are connected to the casing 56. On the other hand, a power generation air introduction pipe 74 and a combustion gas discharge pipe 82 are connected to the heat exchanger 22.

  The to-be-reformed gas supply pipe 60 is a pipe line that supplies a to-be-reformed gas for reforming such as city gas into the casing 56. The water supply pipe 62 is a pipe that supplies water used when steam reforming the gas to be reformed into the casing 56. The power generation air introduction pipe 74 is a conduit for supplying power generation air (oxidant gas) for causing a power generation reaction with the fuel gas generated by the reforming to the inside of the casing 56. The combustion gas discharge pipe 82 is a pipe that discharges the combustion gas generated as a result of burning the remaining fuel gas and oxidant gas that did not contribute to power generation to the outside of the casing 56.

  Next, the internal structure of the fuel cell module 2 of the fuel cell device according to the present invention will be described with reference to FIGS. FIG. 2 is a cross-sectional view of the fuel cell module 2 cut along a cutting plane parallel to the xy plane of FIG. FIG. 3 is a side view of the fuel cell module 2 in the short direction showing a state where a part of the casing 56 is removed from the fuel cell module 2 shown in FIG. FIG. 4 is a perspective view showing a state where the casing 56 and the heat exchanger 22 are removed from the fuel cell module 2 shown in FIG. FIG. 5 is a longitudinal side view of the fuel cell module 2 showing a state where the casing 56 and the heat exchanger 22 are removed from the fuel cell module 2 shown in FIG.

  As shown in FIGS. 1 to 3, the casing 56 covers the entire fuel cell stack 12. The fuel cell stack 12 is formed of an assembly of fuel cell units 16 arranged in parallel with each other in an upright posture. As shown in FIG. 4, the fuel cell stack 12 has a substantially rectangular parallelepiped outline that is longer in the A direction than in the B direction, and is parallel to the xz plane along the lower surface of the reformer 20. An upper surface that extends parallel to the xz plane along the upper surface of the fuel gas tank 68; a pair of long side surfaces that extend parallel to the yz plane; and a pair of long side surfaces that extend parallel to the xy plane. A pair of short side surfaces that connect each other.

  In the case of the present embodiment, an evaporating mixer for evaporating the water supplied from the water supply pipe 62 is provided adjacent to the reformer 20. The evaporative mixer is heated by a combustion gas combusted in a combustion section 18 described later, and converts water into steam and mixes the steam with a gas to be reformed (city gas or the like). The reformed gas supply pipe 60 and the water supply pipe 62 are both led to the interior of the casing 56 and then connected to the reformer 20. More specifically, as shown in FIG. 3, the reformed gas supply pipe 60 and the water supply pipe 62 are connected to one end on the right side in FIG. 3, which is the upstream end of the reformer 20.

  The reformer 20 is disposed further above the combustion unit 18 formed above the fuel cell stack 12. Therefore, the reformer 20 is heated by the combustion heat of the remaining fuel gas and oxidant gas that has not contributed to power generation after the power generation reaction, and serves as an evaporative mixer and as a reformer that causes the reforming reaction. And is configured to play a role. The other end on the left side in FIG. 3 that is the downstream end of the reformer 20 is connected to the upper end of a fuel supply pipe 66 (third supply pipe). A lower end side 66 a (see FIG. 2) of the fuel supply pipe 66 is disposed so as to enter the fuel gas tank 68.

  As shown in FIGS. 3 and 4, the fuel gas tank 68 is provided directly below the fuel cell stack 12. A plurality of small holes (not shown) are formed along the longitudinal direction (A direction) on the outer periphery of the lower end side 66 a of the fuel supply pipe 66 inserted into the fuel gas tank 68. The fuel gas generated by the reformer 20 is uniformly supplied in the longitudinal direction into the fuel gas tank 68 through the plurality of small holes (not shown). The fuel gas supplied to the fuel gas tank 68 is supplied into a fuel gas flow path (details will be described later) inside each fuel cell unit 16, and the inside of the fuel cell unit 16 is directed from its lower end to its upper end. Ascend to the combustion section 18.

  As shown in FIGS. 2 to 4, the support member 30 a (first support member) and the support member 30 b (second support member) face the side surfaces of the pair of long sides of the fuel cell stack 12, respectively. Has been placed. The support members 30a and 30b are opposed to the long side surface of the fuel cell stack 12 on the inward surfaces. The support members 30a and 30b have a plane-symmetric structure with respect to an intermediate surface (not shown) defined at an equal distance from the pair of long side surfaces of the fuel cell stack 12. In the present embodiment, the intermediate surface is defined in parallel to the xy plane and is defined by a plane passing through the center position in the longitudinal direction of the fuel cell stack 12.

  The support members 30a and 30b include a side plate 31 that extends along the side surface of the fuel cell stack 12, and an upper plate 32 that protrudes inward from the upper end of the side plate 31 and extends parallel to the xz plane. The aforementioned reformed gas supply pipe 60 and water supply pipe 62 are arranged outside the side plate 31 of one support member 30a, and the aforementioned fuel supply pipe 66 is arranged outside the side plate 31 of the other support member 30b. Yes. The to-be-reformed gas supply pipe 60, the water supply pipe 62, and the fuel supply pipe 66 are opposed to the outward faces of the corresponding side plates 31, respectively. The support members 30a and 30b are made of a metal material such as stainless steel.

  The reformer 20 is fixed to the upper surface of each upper plate 32 of the pair of support members 30a and 30b. One end or upstream end of the reformer 20 is fixed to the upper plate 32 of the support member 30a by a pair of spacers 33a and 33b, while the other end or downstream end of the reformer 20 is similarly a pair of spacers. It is fixed to the upper plate 32 of the support member 30b by 33a, 33b. The spacers 33a and 33b may be fixed to the bottom surface of the reformer 20, for example, by welding or screwing. The spacers 33a and 33b may be fixed to the upper plate 32 by, for example, screwing. The number of spacers may be set to a number larger than a pair.

  As is apparent from FIGS. 2 and 5, an air flow path 34 is formed between the upper plates 32 of the support members 30 a and 30 b and the bottom surface of the reformer 20 by the action of the spacers 33 a and 33 b. The remaining fuel gas and oxidant gas that did not contribute to power generation after the power generation reaction, and the combustion gas generated by the combustion of the fuel gas and oxidant gas in the combustion unit 18 pass through the air flow path 34. Circulate. In the present embodiment, the spacers 33a and 33b are arranged so that the air flow path 34 on the support member 30a and the air flow path 34 on the support member 30b are formed symmetrically with respect to the above-described intermediate surface. In other words, the air flow path 34 is disposed at the same position when viewed in the longitudinal direction of the fuel cell stack 12.

  As apparent from FIGS. 4 and 5, the reformed gas supply pipe 60 and the water supply pipe 62 are formed with stretchable regions 35a and 35b, respectively, along the longitudinal direction thereof. The expansion / contraction regions 35a and 35b are thinner than the other portions of the reformed gas supply pipe 60 and the water supply pipe 62, have a bellows shape, and are configured to be extendable / contractable along the longitudinal direction. Yes. The expansion / contraction regions 35 a and 35 b are made of a metal material similarly to the reformed gas supply pipe 60 and the water supply pipe 62, and are integrated with the reformed gas supply pipe 60 and the water supply pipe 62. A support member 30 a is disposed between the expansion / contraction areas 35 a and 35 b and the fuel cell stack 12, and the expansion / contraction areas 35 a and 35 b face the outward surface of the side plate 31.

  These expansion / contraction regions 35a and 35b can be extended or contracted in the longitudinal direction of the reformed gas supply pipe 60 and the water supply pipe 62, for example, by the function of the bellows shape. Further, the parts of the reformed gas supply pipe 60 and the water supply pipe 62 above the stretchable areas 35a and 35b, and the parts of the reformed gas supply pipe 60 and the water supply pipe 62 below the stretchable areas 35a and 35b. Relative displacement can be tolerated. Similarly, an expansion / contraction region may be formed in the fuel supply pipe 66 (not shown).

  FIG. 6 is a perspective view schematically showing the structure of the spacers 33a and 33b and the support member 30a. As is clear from FIG. 6, all the spacers 33a and 33b have the same shape and the same size. In the present embodiment, the spacers 33a and 33b are formed of, for example, a flat plate that extends in the z-axis direction and extends flat in parallel with the xz plane. As described above, the spacers 33a and 33b on the one support member 30a and the spacers 33a and 33b on the other support member 30b are symmetrical with respect to the above-described intermediate plane. It is arranged to be formed.

  Further, the spacers 33a and 33b on the one support member 30a and the spacers 33a and 33b on the other support member 30b are defined at equal distances from the side surfaces of the pair of short sides of the fuel cell stack 12. It is arrange | positioned in the plane-symmetrical position with respect to 2 intermediate | middle surfaces. In other words, when viewed in the short direction of the fuel cell module 2, the spacers 33a and 33a are arranged at the same position. The second intermediate surface extends along the yz plane and is defined by a plane passing through the center position of the fuel cell stack 12 in the short direction. The arrangement, shape, and size of the spacers 33a and 33b may be changed depending on the flow rate of the oxidant gas or the fuel gas that flows through the fuel cell stack 12.

  Next, a structure for supplying power generation air into the fuel cell module 2 will be described with reference to FIGS. 7 and 8 in addition to FIGS. FIG. 7 is a schematic diagram corresponding to FIG. 2 and shows the flow of the oxidant gas and the combustion gas. FIG. 8 is a schematic diagram corresponding to FIG. 3, and similarly shows the flow of the oxidant gas and the combustion gas. As shown in these drawings, a heat exchanger 22 is disposed above the reformer 20. In the heat exchanger 22, a plurality of combustion gas pipes 70 and a power generation air passage 72 formed around the combustion gas pipes 70 are provided.

  The aforementioned power generation air introduction pipe 74 is attached to one end side (the right end in FIG. 3) of the upper surface of the heat exchanger 22. The oxidant gas is introduced into the heat exchanger 22 from the power generation air flow rate adjustment unit (not shown) by the power generation air introduction pipe 74. A pair of outlet ports 76 a and 76 a of the power generation air flow path 72 are formed on the other end side (the left end in FIG. 3) on the upper side of the heat exchanger 22. Each of the outlet ports 76a is connected to a communication channel 76. Further, as shown in FIG. 2, power generation air supply passages 77 are formed on the outer sides of the casing 56 in the width direction.

  Therefore, the oxidant gas is supplied to the power generation air supply path 77 from the outlet port 76 a of the power generation air flow path 72 and the communication flow path 76. The power generation air supply path 77 is formed along the longitudinal direction of the fuel cell stack 12. Further, a plurality of oxidant gases for blowing out the oxidant gas toward each fuel cell unit 16 of the fuel cell stack 12 in the power generation chamber 10 at a position corresponding to the lower side of the fuel cell stack 12. The blower outlets 78a and 78b are formed. The oxidant gas blown out from these air outlets 78 a and 78 b flows from the lower part to the upper part of the fuel cell unit 16 along the outside of each fuel cell unit 16. That is, the oxidant gas flow path 79 is formed between the fuel cell units 16 and 16.

  Next, a structure for discharging combustion gas generated by combustion of fuel gas and oxidant gas will be described. The combustion gas generated above the fuel cell unit 16 rises in the combustion section 18 and reaches the rectifying plate 21. The rectifying plate 21 is provided with an opening 21a, and combustion gas is guided into the opening 21a. At the same time, the combustion gas rises through the air flow paths 34 and 34 formed at both ends of the reformer 20, and is guided into the opening 21a. The combustion gas that has passed through the opening 21 a reaches the other end side of the heat exchanger 22. In the heat exchanger 22, a plurality of combustion gas pipes 70 are provided for discharging combustion gas. A combustion gas discharge pipe 82 is connected to the downstream end side of these combustion gas pipes 70, and the combustion gas is discharged to the outside through the combustion gas discharge pipe 82. At this time, the remaining oxidant gas that has not been used for the combustion gas or fuel flows through the air flow paths 34 and 34.

  Next, the fuel cell unit 16 will be described with reference to FIG. FIG. 9 is a partial cross-sectional view showing the fuel cell unit 16. As shown in FIG. 9, the fuel cell unit 16 includes a fuel cell 84 and inner electrode terminals 86 respectively connected to the vertical ends of the fuel cell 84. The fuel cell 84 is a tubular structure extending in the vertical direction, and includes a cylindrical inner electrode layer 90 that forms a fuel gas flow path 88 therein, and a cylindrical outer electrode layer that extends concentrically with the inner electrode layer 90. 92, and an electrolyte layer 94 disposed between the inner electrode layer 90 and the outer electrode layer 92. The inner electrode layer 90 is a fuel electrode through which fuel gas passes and becomes a (−) electrode, while the outer electrode layer 92 is an air electrode in contact with air and becomes a (+) electrode.

  Since the inner electrode terminals 86 attached to the upper end and the lower end of the fuel cell unit 16 have the same structure, the inner electrode terminal 86 attached to the upper end will be specifically described here. The upper part 90 a of the inner electrode layer 90 includes an outer peripheral surface 90 b and an upper end surface 90 c exposed to the electrolyte layer 94 and the outer electrode layer 92. The inner electrode terminal 86 is connected to the outer peripheral surface 90b of the inner electrode layer 90 through a conductive sealing material 96, and further directly contacts the upper end surface 90c of the inner electrode layer 90, whereby the inner electrode layer 90 is electrically connected. Connected. A fuel gas passage 98 communicating with the fuel gas passage 88 of the inner electrode layer 90 is formed at the center of the inner electrode terminal 86.

  The inner electrode layer 90 includes, for example, a mixture of Ni and zirconia doped with at least one selected from rare earth elements such as Ca, Y, and Sc, and Ni and ceria doped with at least one selected from rare earth elements. The mixture is formed of at least one of Ni and a mixture of lanthanum garade doped with at least one selected from Sr, Mg, Co, Fe, and Cu.

  The electrolyte layer 94 is, for example, zirconia doped with at least one selected from rare earth elements such as Y and Sc, ceria doped with at least one selected from rare earth elements, lanthanum gallate doped with at least one selected from Sr and Mg, Formed from at least one of the following.

  The outer electrode layer 92 includes, for example, lanthanum manganite doped with at least one selected from Sr and Ca, lanthanum ferrite doped with at least one selected from Sr, Co, Ni and Cu, Sr, Fe, Ni and Cu. It is formed from at least one of lanthanum cobaltite doped with at least one selected from the group consisting of silver and silver.

  Next, the fuel cell stack 12 will be described with reference to FIG. FIG. 10 is a perspective view showing the fuel cell stack 12. As shown in FIG. 10, the fuel cell stack 12 is supported by a ceramic fuel gas tank upper plate 68a and an upper support plate 100 at the lower end and the upper end for each assembly of 16 fuel cell units 16, respectively. Has been. The fuel gas tank upper plate 68a and the upper support plate 100 are formed with through holes through which the inner electrode terminal 86 can pass.

  Further, a current collector 102 and an external terminal 104 are attached to the fuel cell unit 16. The current collector 102 includes an inner electrode terminal 86 attached to the inner electrode layer 90 that is a fuel electrode, and an outer peripheral surface of the outer electrode layer 92 that is an air electrode of an assembly of adjacent fuel cell units 16. Connect electrically. Further, external terminals 104 are respectively connected to the inner electrode terminals 86 at the upper end and the lower end of the assembly of the two fuel cell units 16 located at the end of the fuel cell stack 12. These external terminals 104 are connected to the external terminals 104 of the assembly of the fuel cell units 16 at the end of the assembly of the adjacent fuel cell units 16, and all 160 fuel cell units 16 are connected in series. Is done.

  Next, a case where the support members 30a and 30b are thermally expanded will be described with reference to FIG. As shown in FIG. 11, the reformer 20 is heated by the combustion heat of the fuel gas and the oxidant gas, and the support members 30a and 30b that support the reformer 20 are thermally expanded under the influence of the heat. The position of the vessel fluctuates. Since a normal temperature fluid flows through the reformed gas supply pipe 60 and the water supply pipe 62, a difference in thermal expansion occurs between the support member 30 a and the reformed gas supply pipe 60 and the water supply pipe 62. As a result, stress may be generated at the connecting portion between the reformer 20 and the reformed gas supply pipe 60 and the water supply pipe 62, which may cause damage. However, in the present embodiment, since the stretchable regions 35a and 35b are formed in the reformed gas supply pipe 60 and the water supply pipe 62, relative expansion due to the expansion or contraction of the stretchable areas 35a and 35b is caused by the difference in thermal expansion. Displacement can be tolerated.

  By comprising in this way, deterioration of the connection part of piping connected to the reformer 20, and the reformer 20 and piping can be suppressed, and it can be used over a long period of time.

  Further, since the high-temperature fuel gas in which the reforming reaction has occurred passes near the support member 30b of the reformer 20, the support member 30b becomes high temperature due to the influence of heat. On the other hand, the support member 30a of the reformer 20 is cooler than the support member 30b because a relatively low temperature fluid flows through the reformed gas supply pipe 60 and the water supply pipe 62. For this reason, a difference in thermal expansion occurs between the support members 30a and 30b. As a result, the reformer 20 is inclined to cause piping to be deformed, and stress may be generated at the connection portion between the pipe and the reformer 20 to cause damage. However, in the present embodiment, the stretchable regions 35a and 35b are formed so as to allow relative displacement in the horizontal direction (A direction and lateral direction in FIG. 1), as shown in FIG. The stress applied to the connection portion can be suppressed. The expansion / contraction direction of the expansion / contraction regions 35a and 35b may be configured to allow relative variation in the horizontal direction (the B direction and the horizontal direction in FIG. 1).

  By configuring the expansion / contraction regions 35a and 35b in this way, it is possible to absorb the bending of the piping caused by the inclination of the reformer 20 due to the thermal expansion of the support members 30a and 30b. As a result, the stress applied to the connection portion between the reformer 20 and the reformed gas supply pipe 60 and the water supply pipe 62 can be suppressed, and deterioration at the connection portion can be further suppressed.

  Further, since the amount of heat taken when water passes through the water supply pipe 62 is larger than the amount of heat taken by the reformed gas through the reformed gas supply pipe 60, the water supply pipe 62 and the reformed gas supply pipe A difference in thermal expansion also occurs between 60 and 60. Therefore, in this embodiment, in the expansion / contraction area 35a provided in the reformed gas supply pipe and the expansion / contraction area 35b provided in the water supply pipe, the extension amount of the expansion / contraction area 35b provided in the water supply pipe is changed. It forms so that it may become larger than the expansion amount of the expansion-contraction area | region 35a provided in the quality gas supply pipe | tube, and a thermal expansion difference is absorbed. As a result, the stress caused by the difference in thermal expansion between the water supply pipe 62 and the reformed gas supply pipe 60 can be suppressed.

  Further, an evaporative mixer that is disposed adjacent to the reformer 20 and vaporizes the water supplied from the water supply pipe 62 into water vapor before being supplied to the reformer 20 is supported by the support members 30a and 30b. Yes. The evaporative mixer is configured so as to be disposed closer to the expansion / contraction regions 35 a and 35 b than the reformer 20.

  With this configuration, even when stress is generated in the reformed gas supply pipe 60 and the water supply pipe 62 due to the difference in thermal expansion between the support member 30a and the support member 30b, the stretchable areas 35a and 35b can absorb the stress. it can. Thereby, the deterioration in the connection part of the to-be-reformed gas supply pipe 60 and the water supply pipe 62 and the reformer can be further suppressed.

  Further, as shown in FIGS. 11 and 12, the stretchable regions 35 a and 35 b are disposed below the combustion unit 18. In other words, the fuel cell 84 is disposed at the height where it is disposed. As a result, the combustion heat is directed upward from the fuel cell 84, so that the influence of the heat generated in the combustion section 18 on the expansion / contraction regions 35a, 35b can be reduced, and the expansion / contraction performance of the expansion / contraction regions 35a, 35b can be reduced. Can be prevented. Therefore, it is possible to further suppress deterioration at the connection portion between the reformer 20 and the pipe.

  The support member 30 a is formed so as to be interposed between the expansion / contraction regions 35 a and 35 b provided in the reformed gas supply pipe 60 or the water supply pipe 62 and the fuel cell 84.

  By configuring in this way, the support members 30a and 30b can reduce the thermal effect of the combustion gas generated in the combustion section 18 on the expansion / contraction regions 35a and 35b and the thermal effect propagated from the fuel cell unit 16 side. Therefore, the expansion / contraction performance of the expansion / contraction regions 35a and 35b can be prevented. As a result, the stress applied to the connecting portion between the reformer 20 and the pipe can be suppressed, and deterioration of the connecting portion can be prevented.

  The embodiments of the present invention have been described above with reference to specific examples. However, the present invention is not limited to these specific examples. In other words, those specific examples that have been appropriately modified by those skilled in the art are also included in the scope of the present invention as long as they have the characteristics of the present invention. For example, the elements included in each of the specific examples described above and their arrangement, materials, conditions, shapes, sizes, and the like are not limited to those illustrated, and can be changed as appropriate. Moreover, each element with which each embodiment mentioned above is provided can be combined as long as technically possible, and the combination of these is also included in the scope of the present invention as long as it includes the features of the present invention.

2 Fuel cell module 10 Power generation chamber 12 Fuel cell stack 16 Fuel cell unit 18 Combustion unit 20 Reformer 21 Rectifier plate 21a Opening 22 Heat exchanger 30a Support member 30b Support member 31 Side plate 32 Upper plate 33a Spacer 34 Air flow path 35a Expansion / contraction area 35b Expansion / contraction area 56 Casing 60 Reformed gas supply pipe 62 Water supply pipe 66 Fuel supply pipe 66a Lower end side 68 Fuel gas tank 68a Fuel gas tank upper plate 70 Combustion gas pipe 72 Power generation air flow path 74 Power generation air introduction pipe 76 Communication channel 76a Outlet port 77 Power generation air supply channel 78a Air outlet 79 Oxidant gas channel 82 Combustion gas discharge pipe 84 Fuel cell 86 Inner electrode terminal 88 Fuel gas channel 90 Inner electrode layer 90a Upper part 90b Outer peripheral surface 90c Upper end surface 92 Outer electrode layer 94 Electrolyte layer 96 Sealing material 98 Fuel gas Flow path 100 on the support plate 102 current collector 104 external terminal

Claims (6)

In a fuel cell device that generates power using fuel gas and oxidant gas,
A fuel cell stack having a plurality of fuel cells in which fuel gas passages for passing fuel gas are formed;
A reformer disposed above the fuel cell stack and reforming the reformed gas into fuel gas by passing the reformed gas and water from one end to the other; and
A first supply pipe connected to one end of the reformer and supplying a gas to be reformed to the reformer;
A second supply pipe connected to one end of the reformer and supplying water to the reformer;
A third supply pipe connected to the other end of the reformer and supplying fuel gas from the reformer to the fuel gas flow path,
The plurality of fuel cells are erected along each other so that the fuel cell stack has a rectangular parallelepiped shape as a whole,
A first support member and a second support disposed to face one side surface of the fuel cell stack along the standing direction of the fuel cell and the other side surface opposite to the one side surface Members are provided,
The first support member supports the one end side of the reformer, and the second support member supports the other end side of the reformer,
At least one of the first supply pipe and the second supply pipe includes a thermal expansion amount of the first support member and the second support member and a thermal expansion of at least one of the first supply pipe and the second supply pipe. In order to allow relative displacement based on a difference from the amount, an extendable region that is extendable along at least one extending direction of the first supply pipe and the second supply pipe is formed. Fuel cell device. The stretchable region has a first stretchable region provided in the first supply pipe and a second stretchable region provided in the second supply pipe,
The first stretchable region and the second stretchable region absorb the difference between the thermal expansion amount of the first supply pipe and the thermal expansion amount of the second supply pipe, and hence the mutual stretch amount along the stretching direction. The fuel cell device according to claim 1, wherein the fuel cell devices are configured to be different from each other.   The stretchable region allows relative displacement between the first support member and the second support member and at least one of the first supply pipe and the second supply pipe even in a lateral direction orthogonal to the extending direction. The fuel cell device according to claim 1, wherein the fuel cell device is configured as described above. An evaporation chamber disposed adjacent to the reformer and evaporating water supplied from the second supply pipe into water vapor before being supplied to the reformer;
4. The evaporation chamber and the reformer are supported by the first support member and the second support member, and the evaporation chamber is disposed closer to the expansion / contraction region than the reformer. The fuel cell device described in 1.   2. The fuel cell device according to claim 1, wherein the stretchable region is provided at a position corresponding to a height at which the plurality of fuel cells are disposed.   The fuel cell device according to claim 5, wherein the first support member is formed to be interposed between the stretchable region and the fuel cell.

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