Module case and method for assembling module case

Abstract

To more efficiently perform heat exchange using a module case.SOLUTION: The module case includes: an inner case that accommodates the module so as to form an exhaust gas flow path through which exhaust gas discharged from the module flows between the module and the inner case and has a through-hole communicating with the exhaust gas flow path; an outer case that accommodates the inner case so as to form an air flow path through which air supplied to the module flows between the air flow path and the outer case and has a through-hole communicating with the air flow path at a position concentric with the through-hole with a hole diameter larger than the through-hole of the inner case; and a double pipe portion in which an inner pipe joined to the through-hole of the inner case and an outer pipe joined to the through-hole of the outer case and having an inner diameter larger than an outer diameter of the inner pipe are coaxially arranged and exhaust gas is discharged from the inside of the inner pipe and air can be introduced from between an outer surface of the inner pipe and an inner surface of the outer pipe.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] This specification discloses a module case and a method for assembling the module case. [Background technology]

[0002] Conventionally, module cases for housing modules including solid oxide cell stacks have been proposed. For example, Patent Document 1 describes a module case for housing a module, which is formed into a double structure having an inner wall and an outer wall, and in which an exhaust gas flow path through which exhaust gas from the module flows is formed between the module and the inner wall, and an oxygen-containing gas flow path through which oxygen-containing gas flows is formed between the inner wall and the outer wall, thereby performing heat exchange between the exhaust gas and the oxygen-containing gas. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6826619 Summary of the Invention [Problem to be solved by the invention]

[0004] In order to efficiently perform the heat exchange described above, it is conceivable to increase the contact area between the exhaust gas and the oxygen-containing gas as much as possible. However, since the required size of the module case is determined depending on the module to be housed and each flow path cannot be made longer than necessary, there is a limit to how much the contact area can be increased.

[0005] A primary object of the present disclosure is to more efficiently perform heat exchange using a module case. [Means for solving the problem]

[0006] The present disclosure has adopted the following means to achieve the above-mentioned main object.

[0007] The solid oxide cell system of the present disclosure comprises: A module case that houses a module including a solid oxide cell stack, an inner case that houses the module so as to form an exhaust gas flow path between the module and the inner case, the inner case having a through hole that communicates with the exhaust gas flow path through which exhaust gas discharged from the module flows; an outer case that houses the inner case so as to form an air flow path between the inner case and the outer case, through which air supplied to the module flows, and that has a through hole that has a diameter larger than that of the through hole of the inner case and is positioned concentrically with the through hole, and that communicates with the air flow path; a double pipe section in which an inner pipe joined to the through hole of the inner case and an outer pipe joined to the through hole of the outer case and having an inner diameter larger than the outer diameter of the inner pipe are coaxially arranged, and the exhaust gas is discharged from inside the inner pipe and the air can be introduced between the outer surface of the inner pipe and the inner surface of the outer pipe; The gist of the project is to provide the following:

[0008] The solid oxide cell system of the present disclosure includes an inner tube connected to a through hole in the inner case and an outer tube connected to a through hole in the outer case, the inner diameter of which is larger than the outer diameter of the inner tube, arranged coaxially, and a double-pipe section through which exhaust gas is discharged from the inside of the inner tube and through which air can be introduced between the outer surface of the inner tube and the inner surface of the outer tube. This allows heat exchange between exhaust gas and air to occur not only between the exhaust gas flow path and the air flow path but also in the double-pipe section, increasing the contact area for heat exchange. This allows for more efficient heat exchange using the module case. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic diagram of a solid oxide cell system 10. [Figure 2] FIG. 2 is a perspective view of the module case 30. [Figure 3] FIG. 2 is a perspective view of the module case 30. [Figure 4] FIG. 2 is a front view of the module case 30. [Figure 5] FIG. 2 is a side view of the module case 30. [Figure 6] 5 is a cross-sectional view taken along the line AA in FIG. 4. [Figure 7] FIG. 7 is an enlarged view of the dotted line portion in FIG. 6. [Figure 8] 6 is a cross-sectional view of FIG. 5 taken along line B-B. [Figure 9] FIG. 9 is an enlarged view of the dotted line portion in FIG. 8. [Figure 10] 10A to 10C are explanatory diagrams showing an example of a module case assembling method. [Figure 11] 10 is an explanatory diagram showing the module case 30 during assembly. FIG. [Figure 12] 10 is an explanatory diagram showing the module case 30 during assembly. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0010] An embodiment of the present disclosure will be described with reference to the drawings. FIG. 1 is a schematic diagram of a solid oxide cell system 10. The solid oxide cell system 10 of this embodiment is configured as a solid oxide electrolysis cell (SOEC) system that produces hydrogen by electrolyzing high-temperature steam. The solid oxide cell system 10 includes an electrolysis module 20 including a solid oxide cell stack 21 (hereinafter referred to as the electrolysis cell stack 21), a fuel supply system 40 that supplies steam as a fuel gas to the electrolysis module 20, an air supply system 50 that supplies air as a sweep gas to the electrolysis module 20, a hydrogen recovery system 60 that recovers hydrogen produced by electrolysis, and a power supply 70 that supplies the power required for electrolysis to the electrolysis cell stack 21.

[0011] In addition to the electrolysis cell stack 21 , the electrolysis module 20 includes a fuel preheater 24 , a combustor 25 , heat exchangers 26 , 27 , 28 , a heat insulator 29 , and the like, all of which are housed in a module case 30 .

[0012] The electrolysis cell stack 21 includes a plurality of solid oxide unit cells, each of which includes a solid electrolyte, an anode disposed on one side of the solid electrolyte, and an oxidizer electrode disposed on the other side of the solid electrolyte. The electrolysis cell stack 21 receives power from a power source 70 and electrolyzes water vapor supplied to the anode, thereby producing hydrogen at the anode and oxygen at the oxidizer electrode. The power source 70 can be a system power supply, a renewable energy source (e.g., a solar power generation device), a storage battery, or the like.

[0013] The electrolysis cell stack 21 operates in a high-temperature environment of, for example, about 650 to 800°C, and therefore the solid electrolyte, fuel electrode, and oxidizer electrode are made of ceramic materials. Furthermore, to decompose water vapor into oxygen ions and hydrogen using a catalyst, the fuel electrode is made of a cermet made of ceramic and a metal such as nickel that has catalytic properties. To maintain good catalytic activity of the fuel electrode, it is necessary to keep the fuel electrode in a reducing atmosphere and prevent oxidation of the metal. For this reason, in this embodiment, hydrogen is mixed with the water vapor supplied to the fuel electrode to prevent oxidation.

[0014] One end of a fuel supply pipe 22f is connected to the anode inlet of the electrolysis cell stack 21, and the other end of the fuel supply pipe 22f is connected to a fuel supply system 40. A fuel preheater 24 and a heat exchanger 27 are provided in the fuel supply pipe 22f. One end of anode off-gas piping 23f is connected to the anode outlet of the electrolysis cell stack 21, and the other end of the anode off-gas piping 23f is connected to a hydrogen recovery system 60. Anode off-gas piping 23f is provided with a heat exchanger 26 and a heat exchanger 27.

[0015] One end of an oxidant supply pipe 22a is connected to an oxidant electrode inlet of the electrolysis cell stack 21, and the other end of the oxidant supply pipe 22a is connected to an air supply system 50 via a heat exchanger 28. A heat exchanger 26 is provided in the oxidant supply pipe 22a. One end of an oxidant electrode off-gas pipe 23a is connected to an oxidant electrode outlet of the electrolysis cell stack 21, and the other end of the oxidant electrode off-gas pipe 23a is connected to a combustor 25.

[0016] The combustor 25 includes an ignition device (not shown), and burns a mixed gas of the oxidant electrode off-gas from the oxidant electrode off-gas piping 23a and a portion of the hydrogen recovered by the hydrogen recovery system 60. The combustion exhaust gas generated by the combustion of the mixed gas in the combustor 25 is used as a heating medium for the fuel preheater 24 and the heat exchanger 28. The fuel preheater 24 is disposed in close proximity to the combustor 25, for example, directly above the combustor 25, so as to be able to transfer heat therebetween.

[0017] The fuel supply system 40 includes a water vapor supply system 41 that supplies water vapor to the fuel supply pipe 22f. Although not shown, the water vapor supply system 41 includes, for example, a water tank that stores water (raw water), a water pump that pumps the water in the water tank, and an evaporator that evaporates the water from the water pump. The fuel (water vapor) supplied from the fuel supply system 40 is heated by heat exchange with the anode off-gas in the heat exchanger 27 and is also heated by combustion heat from the combustor 25 in the fuel preheater 24 before being supplied to the anode of the electrolysis cell stack 21. The fuel supply system 40 also includes a hydrogen supply pipe 42 connected to the fuel supply pipe 22f, a hydrogen blower 43 provided in the hydrogen supply pipe 42, and a governor 44 provided in the hydrogen supply pipe 42 upstream of the hydrogen blower 43, in order to mix hydrogen with the water vapor.

[0018] The air supply system 50 includes an air supply pipe 51 having one end connected to a filter 52 and the other end connected to the heat exchanger 28 (connecting pipe 37a), and an air blower 53 installed in the air supply pipe 51. When the air blower 53 is driven, air is drawn into the air supply pipe 51 through the filter 52, where it is heated by heat exchange with the combustion exhaust gas from the combustor 25 in the heat exchanger 28, and then passes through the oxidant supply pipe 22a, where it is heated by heat exchange with the anode off-gas in the heat exchanger 26, and is then supplied to the oxidant electrode of the electrolysis cell stack 21. Note that the heat exchanger 28 of this embodiment is formed inside the module case 30, as will be described later.

[0019] The hydrogen recovery system 60 recovers hydrogen from the anode off-gas emitted from the anode of the electrolysis cell stack 21. The hydrogen recovery system 60 includes a hydrogen tank 61 for storing hydrogen and a condenser 62 for condensing water vapor contained in the anode off-gas to separate the gas and liquid. The condenser 62 has a heat exchange flow path capable of heat exchange with cooling water. The other end of the anode off-gas pipe 23f is connected to the inlet of the heat exchange flow path, and one end of the hydrogen recovery pipe 63 is connected to the outlet of the heat exchange flow path. The hydrogen tank 61 is connected to the other end of the hydrogen recovery pipe 63. The hydrogen recovery pipe 63 is also provided with a variable throttle valve (not shown). The anode off-gas containing hydrogen and water vapor exchanges heat with the cooling water to condense the water vapor contained in the anode off-gas, and is then recovered into the hydrogen tank 61 through the hydrogen recovery pipe 63 by driving a booster pump (not shown). The condensed water obtained by condensing the anode off-gas in the condenser 62 is stored in a water tank (not shown). The water stored in the water tank is used as raw water to generate steam for electrolysis.

[0020] The hydrogen recovery system 60 also includes a recycle pipe 64 that branches off from the hydrogen recovery pipe 63 and is connected to the hydrogen supply pipe 42 between the hydrogen blower 43 and the governor 44, and recycles a portion of the recovered hydrogen as hydrogen for anti-oxidation. The recycle pipe 64 is provided with a flow meter and a variable throttle valve (not shown). The hydrogen recovery system 60 also includes a combustion hydrogen supply pipe 65 that branches off from the hydrogen recovery pipe 63 and is connected to the combustor 25, and supplies a portion of the recovered hydrogen to the combustor 25. The combustion hydrogen supply pipe 65 is provided with a flow meter (not shown).

[0021] The configuration of the module case 30 will be described below. Figures 2 and 3 are perspective views of the module case 30. Figure 4 is a front view of the module case 30. Figure 5 is a side view of the module case 30. Figure 6 is a cross-sectional view taken along line AA in Figure 4. Figure 7 is an enlarged view of the dotted line portion in Figure 6. Figure 8 is a cross-sectional view taken along line BB in Figure 5. Figure 9 is an enlarged view of the dotted line portion in Figure 8. In the following description, the left-right, front-rear, and up-down directions are as shown in each figure. Also, Figure 8 shows the various components arranged inside the module case 30, but this arrangement is merely an example and is not limited to this arrangement.

[0022] 8 , the module case 30 contains the components of the electrolysis module 20, such as the electrolysis cell stack 21, fuel preheater 24, combustor 25, and heat exchanger 26, as well as heat insulating materials 29 arranged around the components. The heat insulating materials 29 are arranged on both the left and right sides and below the components such as the electrolysis cell stack 21.

[0023] The module case 30 includes an inner case 31, an outer case 32, and a double pipe section 35. The inner case 31 is a box-shaped case formed to surround the heat insulating material 29 with a gap therebetween. The inner case 31 has a through-hole 31a formed in the bottom wall at approximately the center of the bottom wall, i.e., approximately the center in the front-rear and left-right directions. The outer case 32 is a box-shaped case formed to surround the inner case 31 with a gap therebetween. In other words, the module case 30 has a double-box structure including the inner case 31 and the outer case 32. The outer case 32 has a through-hole 32a formed in the bottom wall at approximately the center of the bottom wall, i.e., approximately the center in the front-rear and left-right directions. The through-hole 32a is formed concentrically with the through-hole 31a of the inner case 31 and has a larger diameter than the through-hole 31a. Note that a heat insulating material is also provided surrounding the outside of the outer case 32, but this is not shown in the drawings. In addition, in the module case 30, an exhaust gas flow path 33 is formed between the outer wall surface of the heat insulating material 29 and the inner wall surface of the inner case 31, and an air flow path 34 is formed between the outer wall surface of the inner case 31 and the inner wall surface of the outer case 32.

[0024] As shown in Fig. 8, the exhaust gas flow path 33 has an upper flow path 331, a side flow path 332 communicating with the upper flow path 331, and a lower flow path 333 communicating with the side flow path 332. The upper flow path 331 is formed by outer wall surfaces of the left and right upper parts of the heat insulating material 29 and an inner wall surface of the upper part of the inner case 31. The side flow path 332 is formed by outer wall surfaces of the left and right sides of the heat insulating material 29 and inner wall surfaces of the left and right sides of the inner case 31. The lower flow path 333 is formed by outer wall surfaces of the lower part of the heat insulating material 29 and an inner wall surface of the lower part of the inner case 31. The exhaust gas flow path 33 (lower flow path 333) is in communication with a through hole 31a (see Figs. 7, 9, and 11) formed in approximately the center of the bottom wall of the inner case 31. The combustion exhaust gas from the combustor 25 flows from above the combustor 25 (fuel preheater 24) through the left and right upper flow paths 331, flows from top to bottom through the left and right side flow paths 332, flows through the lower flow path 333, and can be discharged to the outside through the through hole 31a.

[0025] As shown in FIG. 8, the air flow path 34 has a lower flow path 341, a side flow path 342 communicating with the lower flow path 341, and an upper flow path 343 communicating with the side flow path 342. The lower flow path 341 is formed by the outer wall surface of the lower part of the inner case 31 and the inner wall surface of the lower part of the outer case 32. The side flow path 342 is formed by the outer wall surfaces on both left and right sides of the inner case 31 and the inner wall surfaces on both left and right sides of the outer case 32. The upper flow path 343 is formed by the outer wall surface of the upper part of the inner case 31 and the inner wall surface of the upper part of the outer case 32. The air flow path 34 (lower flow path 341) communicates with a through-hole 32a (see FIGS. 7, 9, and 11) formed in approximately the center of the bottom wall of the outer case 32. This allows air to be introduced into the air flow path 34 from the outside via the through-hole 32a. The air introduced into the air flow path 34 flows through the lower flow path 341, flows from bottom to top through the left and right side flow paths 342, flows through the upper flow path 343, and then merges and flows into the oxidant supply pipe 22a (heat exchange section 26).

[0026] The double pipe section 35 has a double pipe structure including an inner pipe 36 and an outer pipe 37. The inner pipe 36 is a tubular member whose upper end is joined to the edge of the through hole 31a of the inner case 31. The inner pipe 36 has an exhaust gas discharge path 38 formed therein that communicates with the lower flow path 333 of the exhaust gas flow path 33. Therefore, the combustion exhaust gas that has flowed through the exhaust gas flow path 33 (lower flow path 333) flows through the exhaust gas discharge path 38 in the inner pipe 36 and is discharged.

[0027] The outer pipe 37 is a tubular member whose upper end is joined to the edge of the through-hole 32a of the outer case 32, and is formed with an inner diameter larger than the outer diameter of the inner pipe 36. The through-hole 31a of the inner case 31 and the through-hole 32a of the outer case 32 are formed concentrically, so the inner pipe 36 and the outer pipe 37 are arranged coaxially. The double-pipe section 35 is formed so that the lower ends of the inner pipe 36 and the outer pipe 37 are at approximately the same height, and includes an annular bottom plate 35a joined to the lower ends of the inner pipe 36 and the outer pipe 37. A cylindrical air introduction passage (supply passage) 39 is formed between the outer wall surface of the inner pipe 36 and the inner wall surface of the outer pipe 37. The lower part (bottom) of this air introduction passage 39 is sealed by the annular bottom plate 35a, and the upper part communicates with a lower flow passage 341 of the air flow passage 34.

[0028] The outer tube 37 also protrudes radially outward (for example, forward), and is provided at its lower end with a connecting tube 37a to which the other end of the air supply tube 51 is connected. In the double tube section 35, air introduced into the outer tube 37 from the connecting tube 37a in the radial direction flows axially upward through the air introduction path 39. The outer tube 37 also has, at its upper end, a plurality of circular communication holes 37b that radially penetrate the outer tube 37 and are formed at equal intervals around the entire circumference of the outer tube 37 to connect the air introduction path 39 with the air flow path 34 (lower flow path 341). Therefore, the air introduced from the air supply tube 51 into the connecting tube 37a and flowing upward through the air introduction path 39 flows radially into the lower flow path 341 of the air flow path 34 via the plurality of communication holes 37b so as to be diffused radially.

[0029] The heat exchanger 28 exchanges heat between the combustion exhaust gas flowing through the exhaust gas flow path 33 and the air flowing through the air flow path 34, and also exchanges heat between the combustion exhaust gas flowing through the exhaust gas discharge path 38 and the air flowing through the air introduction path 39. That is, in this embodiment, the heat exchanger 28 is formed by the heat insulating material 29 of the electrolysis module 20, the double-structure module case 30 (the inner case 31 and the outer case 32), and the double pipe section 35.

[0030] Next, an assembly method for assembling the module case 30 will be described. Fig. 10 is an explanatory diagram showing an example of the module case assembly method. This assembly method is performed by a worker in a state where the inner case 31, outer case 32, inner pipe 36, and outer pipe 37 are prepared. The prepared outer pipe 37 is provided with a connecting pipe 37a and a plurality of communication holes 37b. The assembly method is not limited to being performed by a worker, and may also be performed by an assembly robot such as an articulated robot.

[0031] In the module case assembly method, first, a worker places the inner case 31 in the outer case 32 so that the through-hole 31a of the inner case 31 and the through-hole 32a of the outer case 32 communicate with each other (step S100). This forms a double-box structure for the module case 30, and the through-holes 31a and 32a communicate with each other (see FIG. 11). In this state, the through-hole 31a faces the inside and the through-hole 32a faces the outside, so the through-hole 31a is also referred to as the inner hole and the through-hole 32a is also referred to as the outer hole. Next, the worker joins the upper end of the inner pipe 36 to the edge of the through-hole 31a of the inner case 31 by welding (step S110, see FIG. 12). This establishes communication between the exhaust gas flow path 33 and the exhaust gas discharge path 38 in the inner pipe 36. The welding operation in step S110 is performed, for example, with the module case 30 placed upside down and the inner pipe 36 positioned on the edge of the through-hole 31a.

[0032] Next, the worker joins the upper end of the outer pipe 37 to the edge of the through hole 32a of the outer case 32 by welding (step S120). Note that the welding work in step S120 is performed, for example, with the module case 30 placed upside down and the outer pipe 37 positioned on the edge of the through hole 32a. The outer pipe 37 is positioned, for example, by fitting into the through hole 32a and positioning its upper end surface in contact with the bottom surface of the inner case 31. As a result, the air flow path 34 and the air introduction path 39 between the outer wall surface of the inner pipe 36 and the inner wall surface of the outer pipe 37 are communicated via the communication hole 37b, thereby forming a double-pipe structure. Then, the worker joins the annular bottom plate 35a to the lower ends of the inner pipe 36 and the outer pipe 37 by welding (step S130) to form the double-pipe section 35. The inner edge of the annular bottom plate 35a is joined to the lower end of the inner pipe 36, and the outer edge is joined to the lower end of the outer pipe 37. In this way, the assembly of the module case 30 is completed (see FIG. 3, etc.).

[0033] In the solid oxide cell system 10 of the present embodiment described above, an inner pipe 36 joined to the through-hole 31a of the inner case 31 and an outer pipe 37 joined to the through-hole 32a of the outer case 32, with an inner diameter larger than the outer diameter of the inner pipe 36, are coaxially arranged. The system includes a double-pipe section 35 that discharges combustion exhaust gas from the inside of the inner pipe 36 and can introduce air between the outer surface of the inner pipe 36 and the inner surface of the outer pipe 37. This allows heat exchange between the combustion exhaust gas and air to occur not only between the exhaust gas flow path 33 of the inner case 31 and the air flow path 34 of the outer case 32, but also in the double-pipe section 35, thereby increasing the contact area for heat exchange. Therefore, heat exchange using the module case 30 can be performed more efficiently. Note that if the double-pipe section 35 is not provided and the combustion exhaust gas exhaust pipe and the air inlet pipe (supply pipe) are formed in separate locations, two through-holes must be formed in the bottom wall of the outer case 32: one through which the combustion exhaust gas exhaust pipe passes and one through which the air inlet pipe is connected. Therefore, in this embodiment, the number of through-holes formed in the bottom wall of the outer case 32 can be reduced by one.

[0034] Furthermore, the double pipe section 35 has a plurality of communication holes 37b formed at equal intervals around the entire circumference of the outer pipe 37, which radially penetrate the outer pipe 37 to connect the space between the outer surface of the inner pipe 36 and the inner surface of the outer pipe 37 with the air flow path 34 (lower flow path 341). This allows air that has flowed through the air introduction path 39 between the outer surface of the inner pipe 36 and the inner surface of the outer pipe 37 to flow into the air flow path 34 so as to be diffused radially from the plurality of communication holes 37b. This allows air to flow approximately evenly in all directions within the air flow path 34 from the entire circumferential circumference of the outer pipe 37, thereby promoting heat exchange with the combustion exhaust gas and making the heat exchange even more efficient.

[0035] The electrolysis module 20 also includes a combustor 25 that combusts off-gas from the electrolysis cell stack 21. The inner case 31 houses the electrolysis module 20 with the combustor 25 on the upper side, and has a through-hole 31a formed in approximately the center of the bottom wall, while the outer case 32 has a through-hole 32a formed in approximately the center of the bottom wall. This allows a double-pipe section 35 to be provided in the bottom wall of the module case 30, and the exhaust gas flow path 33 allows the combustion exhaust gas to flow from the upper side of the inner case 31 to the bottom wall, thereby increasing the contact area with the air flowing through the air flow path 34. This allows heat exchange using the module case 30 to be performed more efficiently.

[0036] Furthermore, a method for assembling a module case 30 that houses an electrolysis module 20 including an electrolysis cell stack 21 includes steps S100, S110, and S120. Step S100 is a step of housing an inner case 31 that can house the electrolysis module 20 so as to form an exhaust gas flow path 33 between the electrolysis module 20 and the inner case 31 and that has a through hole 31a communicating with the exhaust gas flow path 33, into an outer case 32 that can house the inner case 31 so as to form an air flow path 34 between the inner case 31 and the outer case 32 and that has a through hole 32a that has a larger diameter than the through hole 31a and is positioned concentrically with the through hole 31a and communicates with the air flow path 34. Step S110 is a step of joining an inner pipe 36 to the through hole 31a of the inner case 31. Step S120 is a step of joining an outer pipe 37, whose inner diameter is larger than the outer diameter of the inner pipe 36, to the through hole 32a of the outer case 32. This allows the double pipe section 35 to be formed while preventing misalignment between the inner pipe 36 and the outer pipe 37, and allows the module case 30 to be assembled. Therefore, the module case 30 including the double pipe section 35 can be assembled more easily and the workload can be reduced.

[0037] In the embodiment, the inner case 31 accommodates the combustor 25 on the upper side, but this is not limited thereto, and the combustor 25 may be accommodated on a position other than the upper side, such as on the lower side or the center in the up-down direction. Furthermore, the inner case 31 and the outer case 32 each have the through-holes 31a, 32a formed in approximately the center of their bottom walls, but this is not limited thereto, and the through-holes 31a, 32a may be formed in a position other than the center in either the front-to-back direction or the left-to-right direction, or in a corner of the bottom wall, or other positions other than the center. Alternatively, the inner case 31 and the outer case 32 may have the through-holes 31a, 32a formed in either side walls, not limited to the bottom walls.

[0038] In the embodiment, a plurality of communication holes 37b are formed at equal intervals around the entire circumference of the outer pipe 37 of the double pipe section 35, but this is not limited thereto. For example, if the double pipe section 35 is provided in an offset position, such as a corner of the bottom wall, rather than approximately in the center of the bottom wall of the module case 30 (the inner case 31 and the outer case 32), the plurality of communication holes 37b may be formed offset in the circumferential direction of the outer pipe 37. For example, if the double pipe section 35 is formed in the right front corner of the bottom wall of the module case 30, more communication holes 37b may be formed on the left rear side of the entire circumference of the outer pipe 37 so that more air is supplied to the left rear than to the right front. Furthermore, in the embodiment, the communication holes 37b are circular, but this is not limited thereto, and the communication holes 37b may be formed in a rectangular shape (slit-like) with the longitudinal direction as the circumferential direction.

[0039] In the embodiment, the connecting pipe 37a of the outer pipe 37 is provided so as to protrude radially outward, but this is not limited thereto. For example, the connecting pipe 37a may be provided so as to protrude in a tangential direction of the outer pipe 37, or so as to protrude in the axial direction of the outer pipe 37 (below the annular bottom plate 35a). Furthermore, a flow path forming plate may be provided in the air introduction path 39 between the outer surface of the inner pipe 36 and the inner surface of the outer pipe 37 to diffuse the air within the air introduction path 39 or to regulate the direction of flow so that the air supplied to the air introduction path 39 is diffused substantially uniformly within the air introduction path 39. Furthermore, a flow path forming plate or the like that forms a spiral flow path within the air introduction path 39 may be provided.

[0040] In the embodiment, the module case 30 is assembled by housing the inner case 31 in the outer case 32 to form a double-box structure, and then joining the inner tube 36 and the outer tube 37 in that order, but this is not limited to this. For example, the inner tube 36 may be joined to the inner case 31, the inner case 31 may be housed in the outer case 32 so that the inner tube 36 is inserted into the through-hole 32a, and then the outer tube 37 may be joined to the outer case 32. Alternatively, the inner tube 36 may be joined to the inner case 31, and the outer tube 37 may be joined to the outer case 32, and then the inner case 31 may be housed in the outer case 32 so that the inner tube 36 fits into the outer tube 37. In this way, the method of assembling the module case 30 is not limited to the method shown in FIG. 10 .

[0041] In the embodiment, the solid oxide cell system 10 is configured as an electrolysis system that performs electrolysis to produce hydrogen by high-temperature steam electrolysis. However, the solid oxide cell system 10 may be configured such that the solid oxide cell stack 21 is a reversible solid oxide cell stack, thereby switching between the electrolysis operation and power generation operation that generates power by reacting hydrogen as fuel gas with oxygen contained in the air.

[0042] In the embodiment, the solid oxide cell system 10 is configured as an electrolysis system having a solid oxide electrolysis cell (SOEC) stack as the solid oxide cell stack, but may also be configured as a fuel cell system having a solid oxide fuel cell (SOFC) stack.

[0043] The correspondence between the main elements of the embodiment and the main elements of the present disclosure described in the section on means for solving the problem will be explained. In the embodiment, the inner case 31 corresponds to the "inner case" of the present disclosure, the outer case 32 corresponds to the "outer case," and the double pipe section 35 corresponds to the "double pipe section" (supply / exhaust pipe section). The combustor 25 corresponds to the "combustion section."

[0044] The above describes the forms for implementing the present disclosure using embodiments, but the present disclosure is not limited to these embodiments in any way, and it goes without saying that the present disclosure can be implemented in various forms within the scope that does not deviate from the gist of the present disclosure. [Industrial Applicability]

[0045] The present disclosure is applicable to the solid oxide cell system manufacturing industry and the like. [Explanation of symbols]

[0046] 20 electrolysis module (module), 21 solid oxide cell stack, 25 combustor (combustion section), 30 module case, 31 inner case, 31a through hole, 32 outer case, 32a through hole, 33 exhaust gas flow path, 34 air flow path, 35 double pipe section, 36 inner pipe, 37 outer pipe, 37b communication hole.

Claims

1. A module case that houses a module including a solid oxide cell stack, an inner case that houses the module so as to form an exhaust gas flow path between the module and the inner case, the inner case having a through hole that communicates with the exhaust gas flow path through which exhaust gas discharged from the module flows; an outer case that houses the inner case so as to form an air flow path between the inner case and the outer case, through which air supplied to the module flows, and that has a through hole that has a diameter larger than that of the through hole of the inner case and is positioned concentrically with the through hole, and that communicates with the air flow path; a double pipe section in which an inner pipe joined to the through hole of the inner case and an outer pipe joined to the through hole of the outer case and having an inner diameter larger than the outer diameter of the inner pipe are coaxially arranged, and the exhaust gas is discharged from inside the inner pipe and the air can be introduced between the outer surface of the inner pipe and the inner surface of the outer pipe; A module case comprising:

2. The double pipe portion has a plurality of communication holes formed at equal intervals around the entire circumference of the outer pipe, the communication holes passing through the outer pipe in a radial direction so as to communicate between the outer surface of the inner pipe and the inner surface of the outer pipe and the air flow path. The module case according to claim 1 .

3. the module includes a combustion section that combusts off-gas from the solid oxide cell stack; the inner case accommodates the module with the combustion section at an upper side, and the through hole is formed in approximately the center of the bottom wall, The through hole is formed in the approximate center of the bottom wall of the outer case. The module case according to claim 1 or 2.

4. A method for assembling a module case that houses a module including a solid oxide cell stack, comprising the steps of: a step of accommodating an inner case capable of accommodating the module so as to form an exhaust gas flow path between the inner case and the module, through which exhaust gas discharged from the module flows, and having a through hole communicating with the exhaust gas flow path, in an outer case capable of accommodating the inner case so as to form an air flow path between the inner case and the inner case, through which air supplied to the module flows, and having a through hole with a hole diameter larger than that of the through hole of the inner case and located concentrically with the through hole, and communicating with the air flow path; a step of joining an inner pipe to the through hole of the inner case; a step of joining an outer tube having an inner diameter larger than an outer diameter of the inner tube to the through hole of the outer case; A method for assembling a module case, comprising:

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