Evaporator unit

Abstract

This effectively suppresses the propagation of pressure fluctuations generated in the evaporation section to the cell stack. [Solution] The evaporator unit, which is placed in an insulated case together with a solid oxide cell stack, includes a combustion section for burning a combustible gas, an evaporation section for generating steam by evaporating water introduced from outside the case, a heat exchange section having a flow path through which the steam-containing gas flows and which exchanges heat with the combustion heat of the combustion section before supplying it to the cell stack, a first partition plate separating the evaporation section and the heat exchange section, a second partition plate positioned downstream of the first partition plate in the gas flow direction and partitioning the flow path, and a plurality of partition plates, each having a plurality of through holes through which gas can flow. The first partition plate and the second partition plate are formed such that, when viewed from the flow direction, the centers of the plurality of through holes are offset from each other and the through holes whose opening regions overlap have different opening shapes.

Description

Technical Field

[0001] This specification discloses an evaporator unit.

Background Art

[0002] Conventionally, an evaporator unit used in a solid oxide cell system has been proposed. For example, in Patent Document 1, as an evaporator unit used in a solid oxide fuel cell system, a meandering flow path that meanders and extends from the upper side to the lower side is formed, and water supplied to the upper part is heated and evaporated while flowing through the meandering flow path to generate water vapor. The generated water vapor is used for steam reforming of the raw fuel gas in a reformer on the subsequent stage side of the evaporator, and the fuel gas generated by steam reforming is supplied to a cell stack on the subsequent stage side of the reformer.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the above-described evaporator unit, if film boiling occurs during evaporation of water, pressure fluctuations due to film boiling may propagate through the reformer to the cell stack, and the cell stack may be damaged. Further, in an evaporator unit used in a solid oxide cell system that generates hydrogen by electrolyzing water vapor, the amount of generated water vapor is large, and an influence associated with pressure fluctuations is likely to occur, so sufficient countermeasures are desired. On the other hand, it is also conceivable to fill the entire inside of the evaporator with a pressure-relieving member to suppress pressure fluctuations, but this is not preferable because it causes an increase in pressure loss.

[0005] The main object of the present disclosure is to appropriately suppress the propagation of pressure fluctuations generated in the evaporation section to the cell stack.

Means for Solving the Problems

[0006] This disclosure employs the following means to achieve the primary objectives described above.

[0007] The evaporator unit of this disclosure is An evaporator unit, which is placed in an insulated case together with a solid oxide cell stack, A combustion section for burning flammable gas, The aforementioned case includes an evaporation unit that evaporates water introduced from outside the case to generate water vapor, A heat exchange unit having a flow path through which the gas containing the water vapor flows, which exchanges heat with the combustion heat of the combustion unit before supplying it to the cell stack, A plurality of partition plates comprising: a first partition plate separating the evaporation section and the heat exchange section; a second partition plate positioned downstream of the first partition plate in the gas flow direction and partitioning the flow path, each partition plate having a plurality of through holes through which the gas can flow; Equipped with, The gist of the first partition plate and the second partition plate is that the multiple through holes are formed such that, when viewed from the flow direction, the centers of the multiple through holes are offset from each other, and the through holes whose opening regions overlap have different opening shapes.

[0008] The evaporator unit of this disclosure includes a plurality of partition plates, including a first partition plate that separates the evaporation section and the heat exchange section, and a second partition plate that is positioned downstream of the first partition plate in the gas flow direction and partitions the flow path. The first partition plate and the second partition plate are formed with a plurality of through holes such that, when viewed from the flow direction, the centers of the through holes are offset from each other, and the through holes in which the opening regions overlap have different opening shapes. As a result, even if pressure fluctuations occur due to the evaporation (bumping) of water in the evaporation section, the flow of these pressure fluctuations is prevented from passing linearly through the first partition plate and the second partition plate, thereby preventing the propagation of pressure fluctuations to the cell stack via the heat exchange section. Furthermore, since the propagation of pressure fluctuations is suppressed without filling the entire flow path of the heat exchange section with a pressure-relieving material, an increase in pressure loss can be prevented. Therefore, the propagation of pressure fluctuations generated in the evaporation section to the cell stack can be appropriately suppressed. [Brief explanation of the drawing]

[0009] [Figure 1] This is a schematic diagram of the solid oxide cell system 10, including the evaporator unit 30. [Figure 2] This is an external perspective view of the evaporator unit 30. [Figure 3] This is a side view of the evaporator unit 30. [Figure 4] This is a top view of the evaporator 33. [Figure 5] These are front views of each partition plate 36, 37, and 38. [Figure 6] This is an explanatory diagram showing how the partition plates 36, 37, and 38 are stacked on top of each other. [Modes for carrying out the invention]

[0010] Embodiments of the present disclosure will be described with reference to the drawings. Figure 1 is a schematic diagram of a solid oxide cell system 10 including an evaporator unit 30. The solid oxide cell system 10 of this embodiment is configured as a system capable of performing electrolytic operation. As shown in Figure 1, the solid oxide cell system 10 includes a cell module 20 including a cell stack 21, a hydrogen supply system 40 for supplying hydrogen to the cell module 20, an air supply system 50 for supplying air to the cell module 20, a water supply system 60 for supplying water to the cell module 20, a recovery system 70 for recovering hydrogen and water, and a power supply 80 for supplying power necessary for electrolytic operation to the cell stack 21. The power supply 80 can be a grid power supply, a renewable energy device (e.g., a solar power generation device), a storage battery, etc.

[0011] In addition to the cell stack 21, the cell module 20 includes an evaporator unit 30 which includes a combustor 32 and an evaporator 33 (evaporator section 34, heat exchange section 35), as well as heat exchange sections 25 and 26, all of which are housed in a module case 28 that has thermal insulation properties.

[0012] The cell stack 21 comprises a plurality of solid oxide type single cells, each containing a solid electrolyte, a hydrogen electrode positioned on one side of the solid electrolyte, and an oxygen electrode positioned on the other side of the solid electrolyte. The cell stack 21 is supplied with water vapor from the hydrogen electrode inlet and power from the power supply 80, and the water vapor is electrolyzed to produce hydrogen at the hydrogen electrode and oxygen at the oxygen electrode. The produced hydrogen (generated hydrogen) is discharged from the hydrogen electrode outlet as a hydrogen electrode off-gas along with unreacted water vapor, and the produced oxygen is discharged from the oxygen electrode outlet as an oxygen electrode off-gas along with air, which is a sweep gas supplied from the oxygen electrode inlet. In other words, the cell stack 21 is capable of performing an electrolytic operation in which water vapor is electrolyzed to produce hydrogen at the hydrogen electrode and oxygen at the oxygen electrode.

[0013] Since the cell stack 21 operates in a high-temperature environment, for example, 650-800°C, the solid electrolyte, hydrogen electrode, and oxygen electrode are made of ceramic material. Furthermore, because the catalyst decomposes water vapor into oxygen ions and hydrogen, a cermet made of a catalytic metal such as nickel and ceramic is used for the hydrogen electrode. In order to maintain good catalytic activity of the hydrogen electrode, it is necessary to keep the hydrogen electrode in a reducing atmosphere and prevent oxidation of the metal. For this reason, in this embodiment, hydrogen is mixed into the water vapor supplied to the hydrogen electrode to prevent oxidation.

[0014] One end of the hydrogen electrode inlet pipe 21a is connected to the hydrogen electrode inlet of the cell stack 21, and the other end of the hydrogen electrode inlet pipe 21a is connected to the evaporator 33 (heat exchange section 35) of the evaporator unit 30. The evaporator 33 of the evaporator unit 30 is connected to a hydrogen supply system 40 and a water supply system 60. In addition, one end of the oxygen electrode inlet pipe 21b is connected to the oxygen electrode inlet of the cell stack 21, and the other end of the oxygen electrode inlet pipe 21b is connected to an air supply system 50. The oxygen electrode inlet pipe 21b is provided with a heat exchange section 25 and a heat exchange section 26.

[0015] One end of the hydrogen electrode outlet pipe 21c is connected to the hydrogen electrode outlet of the cell stack 21, and the other end of the hydrogen electrode outlet pipe 21c is connected to the recovery system 70. A heat exchange section 25 is provided in the hydrogen electrode outlet pipe 21c. One end of the oxygen electrode outlet pipe 21d is connected to the oxygen electrode outlet of the cell stack 21, and the other end of the oxygen electrode outlet pipe 21d is connected to the combustor 32 of the evaporator unit 30. The oxygen electrode off-gas containing oxygen discharged from the oxygen electrode outlet is supplied to the combustor 32 as a combustion aid gas.

[0016] The hydrogen supply system 40 includes a hydrogen supply pipe 41 having one end connected to a hydrogen supply source (e.g., hydrogen tank 1) and the other end connected to the evaporator 33 (evaporation section 34) of the evaporator unit 30, and a hydrogen blower 44 installed in the hydrogen supply pipe 41. By driving the hydrogen blower 44, hydrogen is introduced into the evaporator unit 30. Also, a zero governor 43 (equalizing valve) is installed on the upstream side of the hydrogen blower 44 in the hydrogen supply pipe 41, and a negative pressure prevention valve (not shown), an on-off valve 42 (two-way valve), a flow sensor (not shown), etc. are installed on the upstream side of the zero governor 43.

[0017] 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 oxygen electrode inlet pipe 21b, and an air blower 53 provided in the air supply pipe 51. By driving the air blower 53, the air introduced into the air supply pipe 51 through the filter 52 is introduced into the oxygen electrode inlet pipe 21b. The air introduced into the oxygen electrode inlet pipe 21b is heated by heat exchange with the combustion exhaust gas discharged from the evaporator unit 30 to the combustion exhaust gas pipe 21e in the heat exchange section 26 and is also heated by heat exchange with the hydrogen electrode off-gas flowing through the hydrogen electrode outlet pipe 21c in the heat exchange section 25, and then is supplied to the oxygen electrode of the cell stack 21.

[0018] The water supply system 60 includes a water tank 61 for storing water (raw water), a water supply pipe 62 having one end connected to the water tank 61 and the other end connected to the evaporation section 34 of the evaporator unit 30, and a water pump 63 provided in the water supply pipe 62. By driving the water pump 63, the water introduced from the water tank 61 into the water supply pipe 62 is introduced into the evaporator unit 30.

[0019] The recovery system 70 includes a condenser 71 that condenses the water vapor contained in the hydrogen electrode off-gas for gas-liquid separation, a hydrogen recovery pipe 72 that recovers the gas-liquid separated hydrogen, and a condensed water pipe 78 that recovers the condensed water. The condenser 71 is provided outside the module case 28 and has a heat exchange flow path capable of exchanging heat with cooling water. The hydrogen electrode off-gas flowing through the hydrogen electrode outlet pipe 21c is introduced into the heat exchange flow path. The hydrogen electrode off-gas is introduced into the hydrogen recovery pipe 72 after the water vapor contained in the hydrogen electrode off-gas is condensed by heat exchange with the cooling water. A pressure boosting pump 73 is provided in the hydrogen recovery pipe 72. The hydrogen electrode off-gas (hydrogen gas) introduced into the hydrogen recovery pipe 72 after passing through the condenser 71 is recovered into the hydrogen tank 1 by driving the pressure boosting pump 73. Further, the condensed water obtained by condensing the water vapor in the hydrogen electrode off-gas in the condenser 71 is stored in the water tank 61 through the condensed water pipe 78. The condensed water stored in the water tank 61 is used as raw water for generating electrolysis water vapor.

[0020] In addition, the recovery system 70 includes a combustion hydrogen supply pipe 74 branched from the hydrogen recovery pipe 72 and connected to the combustor 32 of the evaporator unit 30, a reflux pipe 75 branched from the hydrogen recovery pipe 72 and connected between the hydrogen blower 44 and the zero governor 43 in the hydrogen supply pipe 41 of the hydrogen supply system 40, and a regulating valve 76 (solenoid valve) installed in the reflux pipe 75. By opening the regulating valve 76, a part of the hydrogen electrode off-gas passing through the condenser 71 can be refluxed and supplied from the hydrogen supply system 40 to the hydrogen electrode of the cell stack 21 through the evaporator unit 30. Thereby, the energy efficiency can be further improved by recycling the hydrogen electrode off-gas after condensation. Note that an orifice may be provided in the reflux pipe 75 instead of the regulating valve 76. Further, the remainder of the hydrogen electrode off-gas passing through the condenser 71 is introduced as combustion hydrogen (combustible gas) into the combustor 32 of the evaporator unit 30 through the combustion hydrogen supply pipe 74 and burned in the combustor 32. Note that the combustion hydrogen supply pipe 74 may be connected to the combustor 32 through a heat exchange section, and the combustion hydrogen may be heated by heat exchange with, for example, the combustion exhaust gas flowing through the combustion exhaust gas pipe 21e in the heat exchange section and then supplied to the combustor 32.

[0021] As shown in Figures 2 to 4, the evaporator unit 30 of this embodiment comprises a combustor 32, an evaporator 33, and a housing 31 that houses the combustor 32 and the evaporator 33 in the same space. The housing 31 has a combustor housing section 31a that has a space extending in the vertical direction and houses the combustor 32 at its bottom, and an evaporator housing section 31b that has a space extending horizontally from the upper space of the combustor housing section 31a and houses the evaporator 33.

[0022] The combustor 32 burns a mixed gas of hydrogen electrode off-gas and oxygen electrode off-gas, and the combustor 32 is equipped with an igniter (not shown) for igniting the mixed gas. The combustion exhaust gas generated by the combustion of the mixed gas in the combustor 32 passes from the combustor housing 31a through the gap between the evaporator 33 and the evaporator housing 31b, and is discharged outside the housing 31 through an opening 31o provided on the upper surface of the evaporator housing 31b and introduced into the combustion exhaust gas piping 21e. The combustion exhaust gas introduced into the combustion exhaust gas piping 21e passes through the heat exchange section 26 and is then discharged outside the module case 28.

[0023] The evaporator 33 has a folded section 33t and is formed in a roughly U-shape when viewed from above. The hydrogen supply pipe 41 of the hydrogen supply system 40 and the water supply pipe 62 of the water supply system 60 are connected to one end wall 33a of the U-shape of the evaporator 33, and the hydrogen electrode inlet pipe 21a is connected to the lower surface near the other end wall 33b of the U-shape. The evaporator 33 also has an evaporation section (evaporation space) 34 and a heat exchange section (heat exchange space) 35 integrated into it. The evaporation section 34 is located on the side of one end wall 33a of the U-shape inside the evaporator 33 and generates steam by evaporating water introduced from the water supply pipe 62. The heat exchange section 35 is adjacent to the evaporation section 34 and extends to the other end wall 33b of the U-shape, including the folded section 33t. It flows steam and gas containing hydrogen through a roughly U-shaped channel to exchange heat with the combustion heat of the combustor 32 before introducing it into the hydrogen electrode inlet pipe 21a.

[0024] The evaporator unit 30 has multiple partition plates arranged inside the evaporator 33. In this embodiment, the evaporator unit 30 includes three partition plates: a first partition plate 36, a second partition plate 37, and a third partition plate 38. The first partition plate 36 separates the evaporation section 34 from the heat exchange section 35. That is, the evaporation section 34 is formed as the space between the end wall 33a of the evaporator 33 and the first partition plate 36. The space in which the evaporation section 34 is formed is directly above the combustor 32 (combustor housing section 31a), and is a space in the evaporator 33 that becomes relatively hot due to the combustion heat of the combustor 32. Therefore, evaporation of water introduced into the evaporation section 34 can be promoted.

[0025] The second partition plate 37 and the third partition plate 38 divide the heat exchange section 35 (flow path) into multiple spaces. The second partition plate 37 is positioned parallel to the first partition plate 36, spaced apart, on one side of the U-shape. The third partition plate 38 is positioned on the other side of the U-shape, approximately symmetrical to the second partition plate 37 across the U-shape. The second partition plate 37 and the third partition plate 38, including the folded portion 33t, form a second heat exchange space (filled space) 35b, which is filled with heat storage balls 39 (alumina or ceramic ball members, see Figure 4). The first heat exchange space 35a, formed by the first partition plate 36 and the second partition plate 37, and the third heat exchange space 35c, formed by the third partition plate 38 and the end wall 33b of the evaporator 33, are empty spaces not filled with balls 39 or other members, and function as buffer spaces to suppress pressure fluctuations within the evaporator 33. Furthermore, the third heat exchange space 35c, like the evaporator 34, is formed directly above the combustor 32 (combustor housing 31a), and is a space within the evaporator 33 that becomes relatively hot due to the combustion heat of the combustor 32.

[0026] Furthermore, in the evaporator 33, the hydrogen electrode outlet pipe 21c is configured to pass horizontally through one side of the U-shape. That is, the hydrogen electrode outlet pipe 21c is configured to pass through a part of the second heat exchange space 35b, the first heat exchange space 35a, and the evaporation section 34. This passing portion functions as a heat exchange section for exchanging heat between the hydrogen electrode off-gas flowing through the hydrogen electrode outlet pipe 21c and the gas containing water vapor. The gas containing water vapor generated in the evaporation section 34 flows through the first partition plate 36 and the second partition plate 37 on one side of the U-shape, passes through the gap of the heat storage ball 39 while folding back at the return section 33t, and flows through the third partition plate 38 on the other side of the U-shape. As a result, the gas generated in the evaporation section 34 and flowing through the heat exchange section 35 is heated from both the inside and outside by heat exchange with the combustion heat from the combustor 32, the combustion exhaust gas, the hydrogen electrode off-gas, and the heat stored in the ball 39, and then introduced into the hydrogen electrode inlet pipe 21a.

[0027] Here, Figure 5 is a front view of each partition plate 36, 37, and 38. Figure 6 is an explanatory diagram showing how each partition plate 36, 37, and 38 are stacked on top of each other. As shown in Figure 5(a), the first partition plate 36 is formed with multiple through holes 136, for example, that penetrate in a circular shape, arranged in a staggered pattern. Note that the multiple through holes 136 are not limited to being arranged in a staggered pattern; they may be arranged in a grid pattern or randomly. The first partition plate 36 also has a support hole 36a formed approximately in the center, which is formed to a diameter that allows the hydrogen electrode outlet pipe 21c to pass through and supports the hydrogen electrode outlet pipe 21c. As shown in Figure 5(b), the second partition plate 37 is formed with multiple through holes 137, for example, that penetrate in a roughly rectangular shape, arranged parallel to each other with the longer side as the vertical direction. That is, the second partition plate 37 has multiple vertically elongated slit-shaped through holes 137. Furthermore, similar to the first partition plate 36, the second partition plate 37 is formed with a diameter that allows the hydrogen electrode outlet pipe 21c to pass through, and a single support hole 37a for supporting the hydrogen electrode outlet pipe 21c is formed approximately in the center. As shown in Figure 5(c), the third partition plate 38 is formed with a plurality of through holes 138, for example, in a roughly rectangular shape, arranged parallel to each other with the longer side as the horizontal direction. That is, the third partition plate 38 has a plurality of horizontally elongated slit-shaped through holes 138. Note that the third partition plate 38 does not have a support hole for the hydrogen electrode outlet pipe 21c, as it is not necessary.

[0028] Furthermore, the through-holes 136, 137, and 138 are formed such that the height H1 from the lower end of the first partition plate 36 to the lower end of the lowest through-hole 136 is higher than the height H2 from the lower end of the second partition plate 37 to the lower end of the through-hole 137, and higher than the height H3 from the lower end of the third partition plate 38 to the lower end of the lowest through-hole 138. This is to suppress the flow of water introduced into the evaporation section 34 partitioned by the first partition plate 36 into the heat exchange section 35 (first heat exchange space 35a). This allows the water introduced into the evaporation section 34 to remain within the evaporation section 34 and promote evaporation. In addition, the through-holes 137 and 138 are formed such that the opening sizes, such as the length (width) L2 of the short side of the through-hole 137 in the second partition plate 37 and the length (width) L3 of the short side of the through-hole 138 in the third partition plate 38, are larger than the outer diameter D of the ball 39 (see Figure 4). This is to prevent the balls 39 from escaping through the through holes 137 and 138 into the first heat exchange space 35a and the third heat exchange space 35c. This helps maintain the packing density of the balls 39 in the second heat exchange space 35b and prevents a decrease in heat exchange efficiency.

[0029] Figure 6(a) shows the state in which the second partition plate 37 is superimposed on the first partition plate 36, with the through-hole 137 of the second partition plate 37 indicated by a dotted line. This superimposed state corresponds to the view from the first partition plate 36 side in the direction of gas flow. As shown in Figures 5(a), (b) and 6(a), the first partition plate 36 and the second partition plate 37 have through-holes 136c and 137c formed at positions that are offset from each other in the horizontal direction (left-right direction in the figures). In addition, there is an overlapping area of ​​the opening regions of the first partition plate 36 and the second partition plate 37 (the shaded area in Figure 6(a)). However, because the through-holes 136 and 137 have centers 136c and 137c offset from each other and are formed with different opening shapes, the area of ​​the overlapping portion can be reduced. Therefore, it is possible to suppress the propagation of pressure fluctuations caused by the evaporation (bumping) of water in the evaporation section 34 by passing linearly through the first partition plate 36 and the second partition plate 37 to the downstream side (second heat exchange space 35b).

[0030] Figure 6(b) shows the state in which the third partition plate 38 is superimposed on the second partition plate 37, with the through-hole 138 of the third partition plate 38 indicated by a dotted line. Note that since the second partition plate 37 and the third partition plate 38 are separated by a folded portion 33t, this state does not actually occur when viewed from the second partition plate 37 side in the direction of gas flow, but it is shown as a hypothetical superimposed state viewed from the direction of gas flow. As shown in Figures 5(b), (c) and 6(b), the second partition plate 37 and the third partition plate 38 have the centers 137c of the through-hole 137 and the centers 138c of the through-hole 138 offset from each other in the horizontal direction (left-right direction in the figures). In addition, there is a portion where the opening areas of the second partition plate 37 and the third partition plate 38 overlap (the shaded area in Figure 6(b)). However, since the through holes 137 and 138 are formed with their centers 137c and 138c offset from each other and with different opening shapes (opening shapes with different vertical and horizontal orientations), the area of ​​the overlapping portion can be reduced. Therefore, it is possible to suppress the propagation of pressure fluctuations generated in the evaporation section 34, which propagate to the second heat exchange space 35b via the first partition plate 36 and the second partition plate 37, to the third heat exchange space 35c by linearly passing through the third partition plate 38. Moreover, since the second partition plate 37 and the third partition plate 38 are separated by a folded portion 33t, it is possible to suppress the direct propagation of pressure fluctuations to the third heat exchange space 35c. Furthermore, by filling the second heat exchange space 35b with balls 39, it is also possible to suppress the direct propagation of pressure fluctuations to the third heat exchange space 35c.

[0031] The evaporator unit 30 of this embodiment, as described above, includes a plurality of partition plates, including a first partition plate 36 that separates the evaporation section 34 and the heat exchange section 35, and a second partition plate 37 that partitions the flow path of the heat exchange section 35. The first partition plate 36 and the second partition plate 37 are formed such that, when viewed from the flow direction, the centers of the plurality of through holes 136, 137 are offset from each other, and the through holes 136, 137 whose opening regions overlap have different opening shapes. This suppresses the linear passage of pressure fluctuations generated in the evaporation section 34 through the first partition plate 36 and the second partition plate 37, thereby suppressing the propagation of pressure fluctuations to the cell stack 21. Furthermore, since the propagation of pressure fluctuations is suppressed without filling the entire flow path of the heat exchange section 35 with a pressure-relieving material, an increase in pressure loss can be prevented. Therefore, the propagation of pressure fluctuations generated in the evaporation section 34 to the cell stack 21 can be appropriately suppressed.

[0032] Furthermore, the system includes a third partition plate 38 as part of the multiple partition plates, which partitions the downstream side of the second heat exchange space 35b (filled space) where multiple balls 39 (multiple heat storage members) are filled, with the upstream side in the flow direction partitioned by the second partition plate 37. The second partition plate 37 and the third partition plate 38 are formed such that, when viewed from the flow direction, the centers of the multiple through holes 137, 138 are offset from each other, the overlapping opening regions of the through holes 137 and 138 have different opening shapes, and the opening size is smaller than that of the balls 39. This prevents pressure fluctuations generated in the evaporation section 34 from passing linearly through the second partition plate 37 and the third partition plate 38 and propagating downstream. In addition, it is possible to maintain the filling density of the balls 39 in the second heat exchange space 35b, prevent a decrease in heat exchange efficiency, and maintain the effect of mitigating pressure fluctuations.

[0033] Furthermore, the evaporator 33 (heat exchange section 35) has a folded section 33t in its flow path, and the second partition plate 37 and the third partition plate 38 are arranged with the folded section 33t separating them so that the second heat exchange space 35b (filled space) is formed in the folded section 33t. Therefore, by separating the second partition plate 37 and the third partition plate 38 with the folded section 33t, the propagation of pressure fluctuations can be suppressed.

[0034] Furthermore, the hydrogen electrode outlet pipe 21c, through which the hydrogen electrode off-gas discharged from the cell stack 21 flows, is positioned to penetrate the flow path of the heat exchange section 35 and the evaporation section 34. The first partition plate 36 and the second partition plate 37 have support holes 36a and 37a formed therein that allow the hydrogen electrode outlet pipe 21c to pass through and be supported. Therefore, the first partition plate 36 and the second partition plate 37 can be used to support the hydrogen electrode outlet pipe 21c, thus reducing the number of parts compared to a system that provides a separate support member for the hydrogen electrode outlet pipe 21c.

[0035] In this embodiment, support holes 36a and 37a for the hydrogen electrode outlet pipe 21c are formed in the first partition plate 36 and the second partition plate 37, but the invention is not limited to this. A separate support member for the hydrogen electrode outlet pipe 21c may be provided, and support holes may not be formed in the first partition plate 36 and the second partition plate 37; instead, through holes for the hydrogen electrode outlet pipe 21c to pass through may simply be formed. Alternatively, the hydrogen electrode outlet pipe 21c is not limited to being arranged to pass through the heat exchange section 35 and the evaporation section 34; the hydrogen electrode outlet pipe 21c does not have to be arranged in this manner.

[0036] In this embodiment, the evaporator 33 is provided with one folded portion 33t, but it is not limited to this, and multiple folded portions may be provided. Alternatively, the evaporator 33 may be configured in a straight line without a folded portion 33t. In such a configuration, the second partition plate 37 and the third partition plate 38 should be arranged parallel to each other with a gap between them.

[0037] In this embodiment, the plurality of partition plates include a third partition plate 38 that partitions the downstream side of the second heat exchange space 35b filled with a plurality of balls 39, but it is not limited to this. For example, the third partition plate 38 may partition the downstream side of the second heat exchange space 35b that is not filled with balls 39. Also, the balls 39 may not be filled in the second heat exchange space 35b, but in the first heat exchange space 35a or the third heat exchange space 35c. Alternatively, the balls 39 may not be filled in any space of the heat exchange section 35. In addition, although there are three partition plates 36, 37, and 38 as the plurality of partition plates, there may be four or more partition plates. Alternatively, the third partition plate 38 may be omitted, and only the first partition plate 36 and the second partition plate 37 may be provided. Furthermore, the opening shapes, sizes, number, and arrangement of the through-holes 136, 137, and 138 in each partition plate 36, 37, and 38 are merely examples. It is sufficient that the partition plates separating the upstream and downstream sides of a single space have through-holes formed such that, when viewed from the flow direction, the centers of the multiple through-holes are offset from each other, and the overlapping opening areas of the through-holes have different opening shapes. In addition, a single partition plate may have a mixture of through-holes with different opening shapes and sizes.

[0038] In this embodiment, the solid oxide cell system 10 performs an electrolytic operation to generate hydrogen by high-temperature steam electrolysis. However, the solid oxide cell system 10 may also be configured to switch between an electrolytic operation to generate hydrogen by steam electrolysis and a power generation operation to generate electricity through the reaction of hydrogen as a fuel gas with oxygen contained in the air, by using the cell stack 21 as a reversible solid oxide cell stack.

[0039] The above describes the forms for implementing this disclosure using embodiments, but this disclosure is not limited in any way to these embodiments, and can of course be implemented in various forms without departing from the gist of this disclosure. [Industrial applicability]

[0040] This disclosure can be used in industries such as the manufacturing of evaporator units. [Explanation of symbols]

[0041] 21 Cell stack, 21c Hydrogen electrode outlet piping (off-gas piping), 28 Module case (case), 30 Evaporator unit, 32 Combustor (combustion section), 34 Evaporator section, 35 Heat exchange section, 36 First partition plate, 37 Second partition plate, 38 Third partition plate, 39 Ball (heat storage component).

Claims

1. An evaporator unit, which is placed in an insulated case together with a solid oxide cell stack, A combustion section for burning flammable gas, The aforementioned case includes an evaporation unit that evaporates water introduced from outside the case to generate water vapor, A heat exchange unit having a flow path through which the gas containing the water vapor flows, which exchanges heat with the combustion heat of the combustion unit before supplying it to the cell stack, A plurality of partition plates comprising: a first partition plate separating the evaporation section and the heat exchange section; a second partition plate positioned downstream of the first partition plate in the gas flow direction and partitioning the flow path, each partition plate having a plurality of through holes through which the gas can flow; Equipped with, The first partition plate and the second partition plate are formed such that, when viewed from the flow direction, the centers of the multiple through holes are offset from each other, and the through holes whose opening regions overlap have different opening shapes. Evaporator unit.

2. The plurality of partition plates further include a third partition plate that partitions the downstream side of a filled space where a plurality of heat storage members are filled, with the upstream side in the flow direction partitioned by the second partition plate. The second partition plate and the third partition plate are formed such that, when viewed from the flow direction, the centers of the multiple through holes are offset from each other, the overlapping opening areas of the through holes have different opening shapes, and the opening size is smaller than that of the heat storage member. The evaporator unit according to claim 1.

3. The heat exchange section has a folded portion in the flow path, The second partition plate and the third partition plate are arranged with respect to the folded portion so that the filling space is formed in the folded portion. The evaporator unit according to claim 2.

4. An off-gas pipe through which off-gas discharged from the cell stack flows is arranged to penetrate the flow path of the heat exchange section and the evaporation section. The first partition plate and the second partition plate have support holes formed through which the off-gas piping passes and is supported. The evaporator unit according to any one of claims 1 to 3.

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