JP6618047B2 - Solid oxide fuel cell device - Google Patents

Description

  The present invention relates to a solid oxide fuel cell device, and more particularly, to a solid oxide fuel cell device including a heat exchanging unit that exchanges heat between exhaust gas generated by burning off-gas and power generation air. .

  A solid oxide fuel cell device (hereinafter also referred to as “SOFC”) uses an oxide ion conductive solid electrolyte as an electrolyte, has electrodes attached to both sides thereof, and supplies fuel gas to one side. The fuel cell operates at a relatively high temperature by supplying an oxidant gas (air, oxygen, etc.) to the other side.

  Conventionally, a solid oxide fuel cell device in which a plurality of layered inter-case passages are formed inside a side plate of a module case is known (see, for example, Patent Document 1). In the fuel cell device described in Patent Document 1, an exhaust passage for exhaust gas generated by burning off-gas is formed outside the storage chamber that houses a plurality of fuel cell units, and further outside the storage chamber. An air passage for supplying power generation air is formed, and a casing is constituted by an outer side plate of the air passage.

  In the fuel cell device, since the exhaust passage and the air passage are provided adjacent to each other, heat exchange is performed between the exhaust gas passing through the exhaust passage and the power generation air passing through the air passage. That is, the heat exchange part is formed along the side plate of the module case.

  Specifically, in the fuel cell device, the exhaust gas flows into the exhaust passage at the upper part of the storage chamber, and flows through the exhaust passage from the upper side to the lower side. On the other hand, the power generation air flows from the lower side to the upper side of the air passage and flows into the storage chamber from the upper part. Therefore, the exhaust gas has a high temperature in the upper part of the exhaust passage before the heat exchange, and a low temperature in the lower part of the exhaust passage after the heat exchange. In addition, the power generation air has a low temperature in the lower part of the air passage before the heat exchange, and a high temperature in the upper part of the air passage after the heat exchange. Therefore, the temperature gradient is formed in the side plate of the module case storage chamber so that the temperature decreases from the upper part toward the lower part.

JP 2012-221659 A

  In order to manufacture the fuel cell device for general consumers (household use), it is necessary to reduce the size and cost while ensuring the performance. In particular, it is necessary to reduce the size of the module case itself. However, if the module case is simply reduced in size, the fuel cell unit may be deteriorated.

  In order to reduce the size of the module case, it is necessary to reduce the pitch (distance) between the fuel cell units and the distance between the fuel cell unit and the side plate of the module case. However, if the distance between the fuel cell unit and the side plate of the module case is reduced, as described above, in the fuel cell device described in Patent Document 1, a vertical temperature gradient is formed on the side plate of the module case storage chamber. For this reason, there is a possibility that a temperature gradient is also generated in the vertical direction also in the fuel cell unit (particularly, the fuel cell unit disposed in the vicinity of the side plate). Further, since the temperature of the side plate of the module case storage chamber becomes lower as it goes downward, the fuel cell unit arranged near the side plate among the plurality of fuel cell units is arranged in the central portion of the storage chamber in a top view. The temperature is lower than that of the fuel cell unit. For this reason, there exists a possibility that temperature nonuniformity may arise in the aggregate | assembly of a some fuel cell unit. Such non-uniform temperature distribution becomes a factor that degrades the fuel cell unit.

  In order to solve such a problem, it is conceivable to form the heat exchange part along the upper region or the top plate of the module case, instead of forming the heat exchange part along the side plate of the module case. That is, it can be considered that heat exchange is performed in a part of the exhaust passage and the air passage formed along the top plate of the module case.

  However, when the side plate of the module case is used as a heat exchange part, it is easy to secure an area necessary for sufficient heat exchange between the exhaust gas and power generation air. When using the vicinity of the top surface as a heat exchange part, the area of the top surface of the module case is smaller than the area of the side plate, so it is difficult to secure a sufficiently large area necessary for heat exchange. Problems arise. In particular, when the module case is downsized, the area of the top surface of the module case becomes smaller, and it becomes difficult to secure a sufficient area for heat exchange.

  Therefore, according to the present invention, it is possible to efficiently exchange heat between the exhaust gas and the power generation air by the heat exchange part formed near the top surface of the module case while downsizing the fuel cell device. An object of the present invention is to provide a solid oxide fuel cell device.

  In order to achieve the above object, the present invention provides a solid oxide fuel cell device including a fuel cell unit that generates electric power by a reaction between a fuel gas obtained by reforming a raw material gas and air. A case, a heat insulating material provided so as to cover the module case, a fuel gas supply passage for supplying the fuel gas to the fuel cell unit, and a module case disposed within the module case to reform the raw material gas using water vapor A reformer that generates fuel gas and supplies the fuel gas to the fuel gas supply passage, and a combustion that burns the fuel gas that did not contribute to the power generation of the fuel cell unit and heats the reformer with the generated exhaust gas And an evaporator that is disposed in the heat insulating material outside the module case, evaporates water by heat exchange with the exhaust gas, and supplies the generated water vapor to the reformer, and a fuel cell An air passage for supplying air to the knit, which is formed at least between the top plate and side plate of the module case and the heat insulating material, and air is directed downward from above the module case along the outer surface of the side plate of the module case. An air passage that flows and an exhaust passage that is provided inside the module case and allows exhaust gas to flow out from the exhaust port. The air passage extends along the air passage with the top plate of the module case interposed therebetween, and the air flowing through the air passage And an exhaust passage configured to exchange heat between the exhaust gas flowing through the exhaust passage and the exhaust gas flowing through the exhaust passage, and the reformer has an exhaust gas generated in the combustion section. The exhaust gas guide member extending in the horizontal direction so as to cover the combustion portion is disposed above the reformer, and the exhaust gas guide member is disposed above the reformer. A convex step projecting downward is provided on the bottom surface so as to face the opening, and the convex step guides exhaust gas rising from the combustion section through the opening to the exhaust passage. To do.

  As described above, in order to reduce the size and cost of the fuel cell device, if the module case is simply reduced in size, the heat between the exhaust gas and the power generation air between the passages between the cases on the side of the module case. In the configuration in which the replacement is performed, the temperature distribution in the vertical direction and the horizontal direction is not uniform in the module case, that is, there is a problem that heat unevenness occurs and the fuel cell unit deteriorates. In order to avoid this, a configuration in which the heat exchange part is formed in the vicinity of the top plate of the module case can be considered.

  Therefore, in the present invention, by improving the heat exchange efficiency in the heat exchange section, even in the heat exchange section provided near the top plate of the module case having a limited area, there is a gap between the exhaust gas and the power generation air. It is configured to allow sufficient heat exchange. Specifically, in the present invention, an evaporator that lowers the temperature of the exhaust gas by the heat of vaporization is provided outside the module case. As a result, heat exchange with the power generation air can be performed in the heat exchanging portion while the temperature of the exhaust gas is maintained at a high temperature.

  Furthermore, in the present invention, a heat exchange part is provided near the top plate of the module case, and an exhaust gas induction member, a reformer, and a combustion part are provided below the heat exchange part in this order. An opening is provided in the reformer, and a convex step is provided on the bottom surface of the exhaust gas guiding member. The convex step portion projects downward so as to face the opening of the reformer. As a result, when the high-temperature exhaust gas generated in the combustion section rises through the opening of the reformer, it collides with the convex step portion of the exhaust gas guiding member.

  Here, unlike the present invention, when the exhaust gas guiding member is not provided with a convex step portion, the exhaust gas rising through the opening of the reformer is moved to the upper part of the reformer. May stay. If the exhaust gas stays, heat is taken away from the exhaust gas during the stay, and the temperature of the exhaust gas decreases before it flows into the heat exchange part, so the heat exchange efficiency for raising the temperature of the power generation air in the heat exchange part Will fall. That is, since the heat exchanging part is arranged on the upper part of the exhaust gas guiding member, heat is generated between the exhaust gas of the heat exchanging part and the exhaust gas near the bottom surface of the exhaust gas guiding member via the exhaust gas guiding member. There is a risk of replacement.

  However, in the present invention, the exhaust gas guiding member promptly guides the high-temperature exhaust gas that has risen through the opening of the reformer to the side by the convex step provided on the bottom surface thereof, It can be led to the heat exchanging section through the exhaust passage in a high temperature state. As a result, in the present invention, the temperature of the exhaust gas flowing into the heat exchange unit can be maintained at a high temperature, and a sufficient amount of heat can be supplied from the exhaust gas to the power generation air in the heat exchange unit. Efficiency can be achieved.

  Thus, in the present invention, even when the heat exchange part has a relatively small area, it is possible to achieve high heat exchange efficiency, so the heat exchange part is formed near the top plate of the module case. Therefore, it is possible to reduce the size and cost of the fuel cell device.

In the present invention, preferably, the exhaust gas guiding member is a case member that forms an internal space communicating with the combustion portion, and a space above the exhaust gas guiding member constitutes an exhaust passage.
According to the present invention thus configured, the exhaust gas guiding member has an internal space that communicates with the combustion section. That is, the internal space of the exhaust gas guiding member forms a gas reservoir into which exhaust gas or air can flow. Thereby, the exhaust gas guiding member functions as a heat insulating member. Therefore, in the present invention, the high-temperature exhaust gas that has risen through the opening of the reformer is heated with the low-temperature exhaust gas in the exhaust passage (heat exchange section) above the exhaust gas guiding member. It is possible to prevent the temperature from being lowered by replacement. As a result, in the present invention, higher heat exchange efficiency in the heat exchange section can be achieved, and the fuel cell device can be reduced in size and cost.

In the present invention, the exhaust passage is preferably formed by the upper surface of the exhaust gas guiding member and the top plate of the module case.
According to the present invention configured as described above, the upper surface of the exhaust gas guiding member 130 functioning as a heat insulating member forms an exhaust passage that constitutes a heat exchanging portion. Heat exchange between the exhaust gas and the air in the air passage located above the passage can be promoted without being taken away by the exhaust gas guiding member on the lower surface of the passage. Furthermore, in the present invention, since the exhaust gas guiding member on the lower surface of the passage functions as a heat reflecting plate, radiant heat from the heat reflecting plate can be given to the exhaust gas and air. Thereby, in this invention, higher heat exchange efficiency in a heat exchange part can be achieved, and it is possible to achieve size reduction and cost reduction of a fuel cell apparatus.

In the present invention, preferably, the exhaust gas guide member is formed of a heat conductive member, and a recess recessed downward is formed in a portion of the upper surface of the exhaust gas guide member on the downstream side of the exhaust passage. Yes.
According to the present invention configured as described above, the high temperature exhaust gas collides with the convex step portion of the exhaust gas guiding member, so that the convex step portion is heated. From the convex step portion, the exhaust gas guiding member is heated. Since heat conduction to other parts cannot be completely blocked, heat conduction to the upper surface of the exhaust gas guiding member also occurs. Then, the temperature difference between the upstream side and the downstream side of the exhaust passage constituting the heat exchange part is reduced on the upper surface of the exhaust gas guiding member, which is disadvantageous for improving the heat exchange efficiency. Therefore, in the present invention, a portion through which the main flow portion of the exhaust gas passes in the exhaust passage is formed by forming a recess in a portion of the upper surface of the exhaust gas guiding member on the downstream side of the exhaust passage where the temperature of the exhaust gas is the lowest. And the exhaust gas guiding member (surface of the recess) is increased so that heat exchange does not easily occur between the exhaust gas and the exhaust gas guiding member at the downstream side of the exhaust passage. Is suppressed. Thereby, in this invention, the higher heat exchange efficiency in a heat exchange part can be achieved.

In the present invention, it is preferable to further include a mixed gas supply pipe for supplying a mixed gas containing a raw material gas and water vapor to the reformer, and the mixed gas supply pipe is modified after extending in the recess of the exhaust gas guiding member. It is connected to the genitalia.
According to the present invention configured as described above, since the mixed gas supply pipe is disposed so as to extend in the recess of the exhaust gas guiding member, the mixed gas in the mixed gas supply pipe is heated by the exhaust gas. For this reason, the heat of the exhaust gas is taken away by the mixed gas supply pipe, which is disadvantageous in improving the heat exchange efficiency. However, preheating of the mixed gas is also necessary. Therefore, in the present invention, the mixed gas supply pipe is disposed along the inside of the concave portion of the exhaust gas guiding member located at the downstream side of the exhaust passage where the temperature of the exhaust gas is lowest, thereby exhausting from the combustion section. The mixed gas supply pipe can be heated by the low temperature exhaust gas after the heat exchange in the heat exchanging unit, not by the high temperature exhaust gas that has reached the lower part of the gas induction member. It is possible to prevent excessive heat from being taken away.

  According to the solid oxide fuel cell device of the present invention, the heat exchange between the exhaust gas and the power generation air is performed by the heat exchange part formed near the top surface of the module case while reducing the size of the fuel cell device. Can be performed efficiently.

1 is an overall configuration diagram showing a solid oxide fuel cell device according to an embodiment of the present invention. 1 is a front sectional view showing a fuel cell module of a solid oxide fuel cell device according to an embodiment of the present invention. FIG. 3 is a cross-sectional view taken along line III-III in FIG. 2. 1 is an exploded perspective view of a module case and an air passage cover of a solid oxide fuel cell device according to an embodiment of the present invention. It is a fragmentary sectional view showing a fuel cell unit of a solid oxide fuel cell device by one embodiment of the present invention. 1 is a perspective view showing a fuel cell stack of a solid oxide fuel cell device according to an embodiment of the present invention. It is side surface sectional drawing which shows a fuel cell module for demonstrating the flow of the gas in the fuel cell module of the solid oxide fuel cell apparatus by one Embodiment of this invention. FIG. 3 is a front cross-sectional view of the fuel cell module taken along line III-III in FIG. 2 for explaining a gas flow in the fuel cell module of the solid oxide fuel cell device according to the embodiment of the present invention. 1 is a partial cross-sectional view of an upper portion of a fuel cell module of a solid oxide fuel cell device according to an embodiment of the present invention. It is explanatory drawing of the exhaust gas which flows around the reformer of the solid oxide fuel cell apparatus by one Embodiment of this invention. 1 is a side sectional perspective view of a reformer and an exhaust gas guiding member of a solid oxide fuel cell device according to an embodiment of the present invention. 1 is a front sectional perspective view of a reformer and an exhaust gas guiding member of a solid oxide fuel cell device according to an embodiment of the present invention. It is explanatory drawing of the exhaust gas which flows through the through-hole of the reformer of the solid oxide fuel cell apparatus by one Embodiment of this invention. It is front sectional drawing of the heat exchange part of the solid oxide fuel cell apparatus by one Embodiment of this invention. It is explanatory drawing of the connection part of the top plate and exhaust pipe of the module case of the solid oxide fuel cell apparatus by one Embodiment of this invention. It is explanatory drawing of the air supply passage for electric power generation on the top plate of the module case of the solid oxide fuel cell apparatus by one Embodiment of this invention. It is explanatory drawing of the exhaust passage under the top plate of the module case of the solid oxide fuel cell apparatus by one Embodiment of this invention. 1 is a perspective view of a plate fin of a solid oxide fuel cell device according to an embodiment of the present invention. It is explanatory drawing of the plate fin arrange | positioned between the side plate of the air passage cover of the solid oxide fuel cell device by one Embodiment of this invention, and the side plate of a module case.

  Next, a solid oxide fuel cell device according to an embodiment of the present invention will be described with reference to the accompanying drawings.

  FIG. 1 is an overall configuration diagram showing a solid oxide fuel cell apparatus (SOFC) according to an embodiment of the present invention. As shown in FIG. 1, a solid oxide fuel cell apparatus (SOFC) 1 according to an embodiment of the present invention includes a fuel cell module 2 and an auxiliary unit 4.

  The fuel cell module 2 includes a housing 6, and a metal module case 8 is built in the housing 6 via a heat insulating material 7. In the power generation chamber 10, which is the lower part of the module case 8, which is a sealed space, a fuel cell that performs a power generation reaction with fuel gas and oxidant gas (hereinafter referred to as “power generation air” or “air” as appropriate). A cell assembly 12 is arranged. The fuel cell assembly 12 includes eight fuel cell stacks 14 (see FIG. 7). The fuel cell stack 14 includes 16 fuel cell units 16 (each including fuel cells). (See FIG. 6). In this example, the fuel cell assembly 12 has 128 fuel cell units 16. In the fuel cell assembly 12, all of the plurality of fuel cell units 16 are connected in series.

  A combustion chamber 18 as a combustion section is formed above the power generation chamber 10 of the module case 8 of the fuel cell module 2. In this combustion chamber 18, residual fuel gas and residual air that have not been used for the power generation reaction are formed. Burns and generates exhaust gas (in other words, combustion gas). Further, the module case 8 is covered with the heat insulating material 7 to suppress the heat inside the fuel cell module 2 from being diffused to the outside air. Further, a reformer 120 for reforming the fuel gas is disposed above the combustion chamber 18, and the reformer 120 is heated to a temperature at which a reforming reaction can be performed by the combustion heat of the residual gas. Yes.

  Further, an evaporator 140 is provided in the heat insulating material 7 above the module case 8 in the housing 6. The evaporator 140 performs heat exchange between the supplied water and the exhaust gas, thereby evaporating the water to generate water vapor, and a mixed gas (hereinafter referred to as “fuel gas”) of the water vapor and the raw fuel gas. Is supplied to the reformer 120 in the module case 8.

Next, the auxiliary unit 4 stores pure water tank 26 that stores water condensed from moisture contained in the exhaust from the fuel cell module 2 and makes it pure water with a filter, and water supplied from the water storage tank. Is provided with a water flow rate adjusting unit 28 (such as a “water pump” driven by a motor). In addition, the auxiliary unit 4 adjusts the flow rate of the fuel gas, the gas shutoff valve 32 for shutting off the fuel supplied from the fuel supply source 30 such as city gas, the desulfurizer 36 for removing sulfur from the fuel gas, A fuel flow rate adjustment unit 38 (such as a “fuel pump” driven by a motor) and a valve 39 that shuts off fuel gas flowing out from the fuel flow rate adjustment unit 38 when power is lost. Further, the auxiliary unit 4 includes an electromagnetic valve 42 that shuts off the air supplied from the air supply source 40, a reforming air flow rate adjusting unit 44 that adjusts the air flow rate, and a power generation air flow rate adjusting unit 45 (with a motor). Driven "air blower", etc., a first heater 46 for heating the reforming air supplied to the reformer 120, and a second heater 48 for heating the power generating air supplied to the power generation chamber. I have. The first heater 46 and the second heater 48 are provided in order to efficiently raise the temperature at the time of startup, but may be omitted.
In this embodiment, the partial oxidation reforming reaction (POX) and the steam reforming reaction (SR) are performed from the POX process in which only the partial oxidation reforming reaction (POX) occurs in the reformer 120 when the apparatus is started. The SR process in which only the steam reforming reaction is performed may be performed via the ATR process in which the mixed autothermal reforming reaction (ATR) occurs, or the POX process may be omitted and the ATR process may be changed to the SR process. You may comprise so that it may transfer, and it may comprise so that a POX process and an ATR process may be abbreviate | omitted and only an SR process may be performed. In the configuration in which only the SR step is performed, the reforming air flow rate adjustment unit 44 is unnecessary.

  Next, a hot water production apparatus 50 to which exhaust gas is supplied is connected to the fuel cell module 2. The hot water production apparatus 50 is supplied with tap water from the water supply source 24, and the tap water is heated by the heat of the exhaust gas and supplied to a hot water storage tank of an external hot water heater (not shown). The fuel cell module 2 is provided with a control box 52 for controlling the amount of fuel gas supplied and the like. Furthermore, the fuel cell module 2 is connected to an inverter 54 that is a power extraction unit (power conversion unit) for supplying the power generated by the fuel cell module to the outside.

  Next, the structure of the fuel cell module of the solid oxide fuel cell device according to an embodiment of the present invention will be described with reference to FIGS. 2 is a side sectional view showing a fuel cell module of a solid oxide fuel cell device according to an embodiment of the present invention, and FIG. 3 is a sectional view taken along line III-III in FIG. 4 is an exploded perspective view of the module case and the air passage cover.

  As shown in FIGS. 2 and 3, the fuel cell module 2 includes a fuel cell assembly 12 and a reformer 120 provided inside a module case 8 covered with a heat insulating material 7, and the module case 8. And an evaporator 140 provided in the heat insulating material 7.

  First, as shown in FIG. 4, the module case 8 includes a substantially rectangular top plate 8a, bottom plate 8c, and a pair of opposing side plates 8b that connect the sides extending in the longitudinal direction (left-right direction in FIG. 2). A cylindrical body and a closed side plate that closes two opposing openings at both ends in the longitudinal direction of the cylindrical body and connects the sides extending in the width direction of the top plate 8a and the bottom plate 8c (left and right direction in FIG. 3) 8d and 8e.

  The module case 8 has a top plate 8 a and side plates 8 b covered with an air passage cover 160. The air passage cover 160 includes a top plate 160a and a pair of opposing side plates 160b. An opening 167 for allowing the exhaust pipe 171 to pass therethrough is provided at a substantially central portion of the top plate 160a. The top plate 160a and the top plate 8a and the side plate 160b and the side plate 8b are separated by a predetermined distance. As a result, there is oxidation between the outside of the module case 8 and the heat insulating material 7, specifically between the top plate 8a and the side plate 8b of the module case 8, and between the top plate 160a and the side plate 160b of the air passage cover 160. Air passages 161a and 161b are formed as agent gas supply passages (see FIG. 3).

  At the lower part of the side plate 8b of the module case 8, a plurality of through holes 8f are provided (see FIG. 4). The power generation air passes through the flow direction adjustment unit 164 from the power generation air introduction pipe 74 provided in the substantially central portion of the top plate 160a of the air passage cover 160 on the closed side plate 8e side of the module case 8. 161a (see FIGS. 2 and 4). Then, the power generation air is injected into the power generation chamber 10 through the air passages 161a and 161b from the outlet 8f toward the fuel cell assembly 12 (see FIGS. 3 and 4).

  Further, plate fins 162 and 163 as heat exchange promoting members are provided inside the air passages 161a and 161b (see FIG. 3). The plate fins 162 are provided in the horizontal direction so as to extend in the longitudinal direction and the width direction between the top plate 8a of the module case 8 and the top plate 160a of the air passage cover 160, and the plate fins 163 are the side plates 8b of the module case 8. And the side plate 160b of the air passage cover 160 and at a position above the fuel cell unit 16 so as to extend in the longitudinal direction and the vertical direction.

  The power generation air flowing through the air passages 161a and 161b is inside the module case 8 inside the plate fins 162 and 163 (specifically along the top plate 8a and the side plate 8b), particularly when passing through the plate fins 162 and 163. Heat exchange is performed with the exhaust gas passing through the exhaust passage). For this reason, the portions where the plate fins 162 and 163 are provided in the air passages 161a and 161b function as a heat exchanger (heat exchange section). The portion provided with the plate fins 162 constitutes a main heat exchanger portion, and the portion provided with the plate fins 163 constitutes a subordinate heat exchanger portion.

  Next, the evaporator 140 is fixed on the top plate 8a of the module case 8 so as to extend in the horizontal direction. Further, a portion 7a of the heat insulating material 7 is disposed between the evaporator 140 and the module case 8 so as to fill these gaps (see FIGS. 2 and 3).

  Specifically, the evaporator 140 includes a fuel supply pipe 63 that supplies water and raw fuel gas (which may include reforming air) to one side end side in the longitudinal direction (left-right direction in FIG. 2). The exhaust gas exhaust pipe 82 (see FIG. 3) for exhaust gas exhaust is connected, and the upper end of the exhaust pipe 171 is connected to the other side end in the longitudinal direction. The exhaust pipe 171 extends downward through an opening 167 formed in the top plate 160 a of the air passage cover 160, and is connected to an exhaust port 111 formed on the top plate 8 a of the module case 8. The exhaust port 111 is an opening through which the exhaust gas generated in the combustion chamber 18 in the module case 8 is discharged to the outside of the module case 8, and is substantially at the center of the top plate 8 a that is substantially rectangular in top view. Is formed.

  In addition, as shown in FIGS. 2 and 3, the evaporator 140 has an evaporator case 141 that is substantially rectangular in top view. The evaporator case 141 is formed by joining two low-profile bottomed rectangular cylindrical upper case 142 and lower case 143 with an intermediate plate 144 sandwiched therebetween.

  Accordingly, the evaporator case 141 has a two-layer structure in the vertical direction, and an exhaust passage portion 140A through which the exhaust gas supplied from the exhaust pipe 171 passes is formed in the lower layer portion, and a fuel layer is formed in the upper layer portion. An evaporation unit 140B that evaporates water supplied from the supply pipe 63 to generate water vapor, and a mixing unit 140C that mixes the water vapor generated in the evaporation unit 140B and the raw fuel gas supplied from the fuel supply pipe 63 are provided. It has been.

The evaporator 140B and the mixer 140C are formed in a space where the evaporator 140 is partitioned by a partition plate provided with a plurality of communication holes (slits). The evaporation unit 140B is filled with alumina balls (not shown).
Similarly, the exhaust passage portion 140A is partitioned into three spaces from the upstream side to the downstream side of the exhaust gas by two partition plates having a plurality of communication holes. The second space is filled with a combustion catalyst (not shown). That is, the evaporator 140 of the present embodiment includes a combustion catalyst device.

  In such an evaporator 140, heat exchange is performed between the water in the evaporation section 140B and the exhaust gas passing through the exhaust passage section 140A, and the water in the evaporation section 140B is evaporated by the heat of the exhaust gas, Water vapor will be generated. Further, heat exchange is performed between the mixed gas in the mixing section 140C and the exhaust gas passing through the exhaust passage section 140A, and the temperature of the mixed gas is raised by the heat of the exhaust gas.

  Further, as shown in FIG. 2, a mixed gas supply pipe 112 for supplying a mixed gas to the reformer 120 is connected to the mixing unit 140C. The mixed gas supply pipe 112 is disposed so as to pass through the inside of the exhaust pipe 171, one end is connected to an opening 144 a formed in the intermediate plate 144, and the other end is formed on the top surface of the reformer 120. Connected to the mixed gas supply port 120a. The mixed gas supply pipe 112 passes through the exhaust passage portion 140A and the exhaust pipe 171 and extends vertically downward into the module case 8, where it is bent approximately 90 ° and extends horizontally along the top plate 8a. , Bent downward by approximately 90 ° and connected to the reformer 120.

  Next, the reformer 120 is disposed so as to extend horizontally along the longitudinal direction of the module case 8 above the combustion chamber 18, and the exhaust gas guiding member 130 is disposed between the top plate 8 a of the module case 8. And fixed to the top plate 8a with a predetermined distance therebetween. The reformer 120 has a substantially rectangular outer shape in a top view, but is an annular structure in which a through hole 120b is formed in the center, and has a casing in which an upper case 121 and a lower case 122 are joined. ing. The through hole 120b is positioned so as to overlap the exhaust port 111 formed in the top plate 8a in a top view, and preferably, the exhaust port 111 is formed at the center position of the through hole 120b.

  On one end side in the longitudinal direction of the reformer 120 (closed side plate 8e side of the module case 8), the mixed gas supply pipe 112 is connected to the mixed gas supply port 120a provided in the upper case 121, and the other end side ( On the closed side plate 8 d side), the fuel gas supply pipe 64 is connected to the lower case 122, and the hydrogen desulfurizer hydrogen extraction pipe 65 extending to the desulfurizer 36 is connected to the upper case 121. Therefore, the reformer 120 receives the mixed gas (that is, raw fuel gas mixed with water vapor (may include reforming air)) from the mixed gas supply pipe 112, reforms the mixed gas therein, The reformed gas (that is, fuel gas) is discharged from the fuel gas supply pipe 64 and the hydrogen extraction pipe 65 for hydrodesulfurizer.

  The reformer 120 is divided into three spaces by the two partition plates 123a and 123b, so that the reformer 120 receives a mixed gas from the mixed gas supply pipe 112 in the reformer 120. And a reforming section 120B filled with a reforming catalyst (not shown) for reforming the mixed gas, and a gas discharge section 120C for discharging the gas that has passed through the reforming section 120B are formed. (See FIG. 2). The reforming unit 120B is a space sandwiched between the partition plates 123a and 123b, and the reforming catalyst is held in this space. The mixed gas and the reformed fuel gas are movable through a plurality of communication holes (slits) provided in the partition plates 123a and 123b. As the reforming catalyst, a catalyst obtained by imparting nickel to the alumina sphere surface or a catalyst obtained by imparting ruthenium to the alumina sphere surface is appropriately used.

The mixed gas supplied from the evaporator 140 through the mixed gas supply pipe 112 is ejected to the mixed gas receiving unit 120A through the mixed gas supply port 120a. The mixed gas is expanded in the mixed gas receiving unit 120A, the jetting speed is reduced, and is supplied to the reforming unit 120B through the partition plate 123a.
In the reforming unit 120B, the mixed gas moving at a low speed is reformed into a fuel gas by the reforming catalyst, and the fuel gas passes through the partition plate 123b and is supplied to the gas discharge unit 120C.
In the gas discharge unit 120C, the fuel gas is discharged to the fuel gas supply pipe 64 and the hydrogen extraction pipe 65 for the hydrodesulfurizer.

  A fuel gas supply pipe 64 as a fuel gas supply passage extends downward in the module case 8 along the closed side plate 8d, is bent approximately 90 ° in the vicinity of the bottom plate 8c, and extends in the horizontal direction. It extends into the manifold 66 formed below the inner side, and further extends horizontally in the manifold 66 to the vicinity of the closed side plate 8e on the opposite side. A plurality of fuel supply holes 64 b are formed in the lower surface of the horizontal portion 64 a of the fuel gas supply pipe 64, and fuel gas is supplied into the manifold 66 from the fuel supply holes 64 b. A lower support plate 68 having a through hole for supporting the fuel cell stack 14 is attached above the manifold 66, and the fuel gas in the manifold 66 is supplied into the fuel cell unit 16. The An ignition device 83 for starting combustion of fuel gas and air is provided in the combustion chamber 18.

  The exhaust gas guiding member 130 is disposed between the reformer 120 and the top plate 8 a so as to extend in the horizontal direction along the longitudinal direction of the module case 8. The exhaust gas guiding member 130 includes a lower guiding plate 131 and an upper guiding plate 132 that are separated by a predetermined distance in the vertical direction, and connecting plates 133 and 134 to which both ends of the longitudinal direction are attached (FIG. 2). FIG. 3). The upper guide plate 132 is bent at both ends in the width direction downward and is connected to the lower guide plate 131. The connecting plates 133 and 134 have upper ends connected to the top plate 8a and lower ends connected to the reformer 120, thereby fixing the exhaust gas guiding member 130 and the reformer 120 to the top plate 8a. ing.

  The lower guide plate 131 is formed with a convex step portion 131a in which the central portion in the width direction (left-right direction in FIG. 3) protrudes downward. On the other hand, as with the lower guide plate 131, the upper guide plate 132 is formed with a recess 132a so that the central portion in the width direction becomes concave downward. The convex step portion 131a and the concave portion 132a extend in the longitudinal direction in parallel in the vertical direction. The mixed gas supply pipe 112 extends horizontally in the recess 132a in the module case 8 and then bends downward in the vicinity of the closed side plate 8e, penetrates the upper guide plate 132 and the lower guide plate 131, It is connected to the reformer 120.

  In the exhaust gas guiding member 130, a gas reservoir 135, which is an internal space that functions as a heat insulating layer, is formed by the upper guiding plate 132, the lower guiding plate 131, and the connecting plates 133 and 134. The gas reservoir 135 is in fluid communication with the combustion chamber 18. That is, the upper guide plate 132, the lower guide plate 131, and the connecting plates 133 and 134 are connected so as to form a predetermined gap, and are not airtightly connected. While it is possible for exhaust gas to flow into the gas reservoir 135 from the combustion chamber 18 during operation, or to allow air to flow in from the outside when stopped, the movement of gas between the inside and outside of the gas reservoir 135 is generally performed. Is moderate.

  The upper guide plate 132 is disposed at a predetermined vertical distance from the top plate 8a, and the exhaust extending in the horizontal direction along the longitudinal direction and the width direction is provided between the upper guide plate 132 and the top plate 8a. A passage 172 is formed. The exhaust passage 172 is arranged in parallel with the air passage 161a with the top plate 8a of the module case 8 interposed therebetween. Inside the exhaust passage 172, plate fins similar to the plate fins 162 and 163 in the air passages 161a and 161b are provided. 175 is arranged. The plate fins 175 are provided at substantially the same location as the plate fins 162 when viewed from above, and face each other in the vertical direction across the top plate 8a. Of the air passage 161a and the exhaust passage 172, in the portion where the plate fins 162 and 175 are provided, efficient heat exchange is performed between the power generation air flowing through the air passage 161a and the exhaust gas flowing through the exhaust passage 172. Thus, the temperature of the power generation air is raised by the heat of the exhaust gas.

  The reformer 120 is disposed at a predetermined horizontal distance from the side plate 8b of the module case 8, and the exhaust gas passes between the reformer 120 and the side plate 8b from below to above. An exhaust passage 173 is formed. Further, the exhaust gas guiding member 130 is also disposed at a predetermined horizontal distance from the side plate 8b, and the exhaust passage 173 includes the passage between the exhaust gas guiding member 130 and the side plate 8b and extends to the top plate 8a. ing. The exhaust passage 173 communicates with the exhaust passage 172 through an exhaust gas introduction port 172a located at the corner between the top plate 8a and the side plate 8b. The exhaust gas introduction port 172a extends in the longitudinal direction in the module case 8.

  Further, the lower guide plate 131 is disposed at a predetermined vertical distance from the top surface of the upper case 121 of the reformer 120, and between the lower guide plate 131 and the upper case 121 and the reformer. The through hole 120b of 120 forms an exhaust passage 174 through which the exhaust gas that has passed through the through hole 120b from the lower side to the upper side is passed. The exhaust passage 174 joins the exhaust passage 173 above the reformer 120.

Next, the fuel cell unit 16 will be described with reference to FIG. FIG. 5 is a partial cross-sectional view showing a fuel cell unit of a solid oxide fuel cell device according to an embodiment of the present invention.
As shown in FIG. 5, the fuel cell unit 16 includes a fuel cell 84 and inner electrode terminals 86 that are caps respectively connected to both 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, a cylindrical outer electrode layer 92, an inner electrode layer 90, and an outer side. An electrolyte layer 94 is provided between the electrode layer 92 and the 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 terminal 86 attached to the upper end side and the lower end side of the fuel cell 84 has the same structure, the inner electrode terminal 86 attached to the upper end side will be specifically described here. The upper portion 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 is further in direct contact with the upper end surface 90c of the inner electrode layer 90, thereby Electrically connected. At the center of the inner electrode terminal 86, a fuel gas channel capillary 98 that communicates with the fuel gas channel 88 of the inner electrode layer 90 is formed.

  The fuel gas passage narrow tube 98 is an elongated thin tube provided so as to extend in the axial direction of the fuel cell 84 from the center of the inner electrode terminal 86. Therefore, a predetermined pressure loss occurs in the flow of the fuel gas flowing from the manifold 66 (see FIG. 2) into the fuel gas passage 88 through the fuel gas passage narrow tube 98 of the lower inner electrode terminal 86. To do. Accordingly, the fuel gas flow passage narrow tube 98 of the lower inner electrode terminal 86 acts as an inflow side flow passage resistance portion, and the flow passage resistance is set to a predetermined value. Further, a predetermined pressure loss also occurs in the flow of the fuel gas flowing out from the fuel gas flow path 88 to the combustion chamber 18 (see FIG. 2) through the fuel gas flow path narrow tube 98 of the upper inner electrode terminal 86. Therefore, the fuel gas flow passage narrow tube 98 of the upper inner electrode terminal 86 acts as an outflow side flow passage resistance portion, and the flow passage resistance is set to a predetermined value.

  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 includes, 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 14 will be described with reference to FIG. FIG. 6 is a perspective view showing a fuel cell stack of a solid oxide fuel cell device according to an embodiment of the present invention.
As shown in FIG. 6, the fuel cell stack 14 includes 16 fuel cell units 16, and these fuel cell units 16 are arranged in two rows of 8 each.
Each fuel cell unit 16 is supported at its lower end by a rectangular lower support plate 68 (see FIG. 2) made of ceramic, and at the upper end, four fuel cell units 16 at both ends are provided, each having a substantially square shape. Is supported by the upper support plate 100. The lower support plate 68 and the upper support plate 100 are formed with through holes through which the inner electrode terminal 86 can pass.

  Furthermore, a current collector 102 and an external terminal 104 are attached to the fuel cell unit 16. The current collector 102 includes a fuel electrode connection portion 102a that is electrically connected to 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. It is integrally formed so as to connect the air electrode connecting portion 102b that is electrically connected. In addition, a silver thin film is formed on the entire outer surface of the outer electrode layer 92 (air electrode) of each fuel cell unit 16 as an electrode on the air electrode side. When the air electrode connecting portion 102b contacts the surface of the thin film, the current collector 102 is electrically connected to the entire air electrode.

  Furthermore, two external terminals 104 are connected to the air electrode of the fuel cell unit 16 located at the end of the fuel cell stack 14 (the far left side in FIG. 6). These external terminals 104 are connected to the inner electrode terminal 86 of the fuel cell unit 16 at the end of the adjacent fuel cell stack 14, and as described above, all 128 fuel cell units 16 are connected in series. It has come to be.

  Next, with reference to FIG.7 and FIG.8, the flow of the gas in the fuel cell module of the solid oxide fuel cell apparatus by one Embodiment of this invention is demonstrated. 7 is a side sectional view showing a fuel cell module of a solid oxide fuel cell device according to an embodiment of the present invention, similar to FIG. 2, and FIG. 8 is similar to FIG. It is sectional drawing along the -III line. FIGS. 7 and 8 are diagrams in which arrows indicating gas flows are newly added in FIGS. 2 and 3, respectively, and show a state in which the heat insulating material 7 is removed for convenience of explanation. In the figure, solid line arrows indicate the flow of fuel gas, broken line arrows indicate the flow of power generation air, and alternate long and short dashed arrows indicate the flow of exhaust gas.

  As shown in FIG. 7, water and raw fuel gas (fuel gas) are fed into an evaporation section 140 </ b> B provided in an upper layer of the evaporator 140 from a fuel supply pipe 63 connected to one end side in the longitudinal direction of the evaporator 140. Supplied. The water supplied to the evaporation section 140B is heated by the exhaust gas flowing through the exhaust passage section 140A provided in the lower layer of the evaporator 140 to become water vapor. The water vapor and the raw fuel gas supplied from the fuel supply pipe 63 flow downstream in the evaporation unit 140B and are mixed in the mixing unit 140C. The mixed gas in the mixing section 140C is heated by the exhaust gas flowing through the lower exhaust passage section 140A.

  The mixed gas (fuel gas) formed in the mixing unit 140C is supplied to the reformer 120 in the module case 8 through the mixed gas supply pipe 112. Since the mixed gas supply pipe 112 passes through the exhaust passage portion 140A, the exhaust pipe 171, and the exhaust passage 172 in order, the mixed gas in the mixed gas supply pipe 112 is further heated by the exhaust gas flowing through these passages. The

  The mixed gas flows into the mixed gas receiving part 120A in the reformer 120, and from here passes through the partition plate 123a and flows into the reforming part 120B. The mixed gas is reformed in the reforming unit 120B to become fuel gas. The fuel gas thus generated passes through the partition plate 123b and flows into the gas discharge part 120C.

  Further, the fuel gas branches from the gas discharge part 120C into the fuel gas supply pipe 64 and the hydrogen extraction pipe 65 for hydrodesulfurizer. The fuel gas that has flowed into the fuel gas supply pipe 64 is supplied into the manifold 66 from the fuel supply hole 64 b provided in the horizontal portion 64 a of the fuel gas supply pipe 64, and from the manifold 66 into each fuel cell unit 16. Supplied.

  Further, as shown in FIGS. 7 and 8, the power generation air is supplied from the power generation air introduction pipe 74 to the air passage 161a. When the power generation air passes through the plate fins 162 and 163 in the air passages 161a and 161b, the exhaust air passes through the exhaust passages 172 and 173 formed in the module case 8 below the plate fins 162 and 163. An efficient heat exchange with the gas is performed and the gas is heated. In particular, since the plate fins 175 are provided in the exhaust passage 172 corresponding to the plate fins 162 of the air passage 161a, the power generation air is discharged from the exhaust gas via the plate fins 162 and the plate fins 175. Perform more efficient heat exchange. Thereafter, the power generation air is injected into the power generation chamber 10 from the plurality of air outlets 8 f provided at the lower portion of the side plate 8 b of the module case 8 toward the fuel cell assembly 12. In the present embodiment, since the exhaust passage is not formed in the side portion of the fuel cell assembly 12, heat exchange between the power generation air and the exhaust gas is suppressed in this portion. Therefore, in the side portion of the fuel cell assembly 12, it is difficult for the temperature gradient in the vertical direction to occur in the power generation air in the air passage 161b.

  Further, as shown in FIG. 8, the fuel gas not used for power generation in the power generation chamber 10 is combusted in the combustion chamber 18 to become exhaust gas (combustion gas), and rises in the module case 8. Specifically, the exhaust gas branches into an exhaust passage 173 and an exhaust passage 174, between the outer surface of the reformer 120 and the side plate 8 b of the module case 8, and through holes 120 b of the reformer 120. From between the reformer 120 and the exhaust gas guiding member 130. At this time, the exhaust gas passing through the exhaust passage 174 is bisected in the width direction by the convex step portion 131a disposed above the through-hole 120b of the reformer 120, and does not stay at the lower portion of the exhaust gas guiding member 130. The gas is guided toward the exhaust passage 173 and is quickly joined to the exhaust gas flowing through the exhaust passage 173.

Thereafter, the exhaust gas flows into the exhaust passage 172 from the exhaust gas inlet 172a. In the exhaust passage 172, the exhaust gas flows in the horizontal direction in the exhaust passage 172 and flows out from the exhaust port 111 formed in the center of the top plate 8 a of the module case 8.
When the exhaust gas flows upward in the exhaust passage 173, heat exchange is performed between the power generation air and the exhaust gas via the plate fins 163 provided in the air passage 161b. Further, when the exhaust gas flows through the exhaust passage 172 in the horizontal direction, a plate fin 175 provided in the exhaust passage 172 and a plate fin 162 provided in the air passage 161 a corresponding to the plate fin 175. Thus, efficient heat exchange is performed between the power generation air and the exhaust gas. In this way, the temperature of the power generation air is raised by the heat of the exhaust gas.

  The exhaust gas flowing out from the exhaust port 111 passes through the exhaust pipe 171 provided outside the module case 8, flows into the exhaust passage part 140A of the evaporator 140, passes through the exhaust passage part 140A, and then evaporates. From the vessel 140 to the exhaust gas discharge pipe 82. As described above, the exhaust gas exchanges heat with the mixed gas in the mixing section 140C of the evaporator 140 and the water in the evaporation section 140B when flowing through the exhaust passage section 140A of the evaporator 140.

  Next, the operation of the reformer of the present embodiment will be described with reference to FIGS. FIG. 9 is a partial cross-sectional view of the upper part of the fuel cell module of the solid oxide fuel cell device according to the embodiment of the present invention, and FIG. 10 is an explanatory view of the exhaust gas flowing around the reformer. 11 and 12 are a side sectional perspective view and a front sectional perspective view of the reformer and the exhaust gas guiding member, respectively, and FIG. 13 is an explanatory diagram of the exhaust gas flowing through the through hole of the reformer.

  As shown in FIG. 9, the power generation air supplied into the power generation chamber 10 moves upward (see the broken line arrow in FIG. 9) and burns off-gas in the combustion chamber 18 to become exhaust gas. If the through hole 120b is not formed in the reformer 120, the exhaust gas passes from the combustion chamber 18 only through the exhaust passage 173 (extending along the inner surface of the side plate 8b of the module case 8), and the module case. It moves toward the upper part in 8. In this case, the flow path distribution of the power generation air is biased to the vicinity of both ends in the width direction of the top surface with respect to the fuel cell assembly 12, and the air supply to the fuel cell unit 16 in the central portion is sufficient. The fuel cell unit 16 in this portion may be deteriorated.

  Therefore, in this embodiment, by providing the reformer 120 with the through hole 120b, the exhaust passage 174 (extending between the reformer 120 and the exhaust gas guiding member 130 from the through hole 120b of the reformer 120) is provided. Forming. Thereby, in this embodiment, exhaust gas can branch from the combustion chamber 18 to the exhaust passage 174 and the exhaust passage 173, and can move toward the upper part in the module case 8 (refer FIG. 10).

  Further, in the present embodiment, specifically, the flow rate of the exhaust gas flowing through the exhaust passage 174 rather than the exhaust passage 173 so that the flow rate ratio of the exhaust gas flowing through the exhaust passage 174 and the exhaust passage 173 becomes a predetermined value. The dimensions of the cross-sectional area of the exhaust passage 173, the cross-sectional area of the exhaust passage 174 on the upper side of the reformer 120, the opening area and the corner R shape of the through-hole 120b, the connecting concave portion, which will be described later, etc. Has been. As a result, even if the distance between the reformer 120 and the fuel cell assembly 12 is close, the exhaust gas can surely flow into the exhaust passage 174. For this reason, in this embodiment, with such an exhaust gas flow, the flow of power generation air is not biased to the vicinity of both end portions in the width direction of the fuel cell assembly 12 in a top view, and also to the central portion. Since it flows, unevenness in the air supply amount of power generation air in the power generation chamber 10 is suppressed, and the flow of power generation air is easily equalized.

  Further, in the present embodiment, the reformer 120 is heated by the exhaust gas that collides with the bottom surface thereof, and then is heated from the side in the width direction by the exhaust gas that passes through the exhaust passage 173. The central part is also heated by the exhaust gas that passes through. Thus, in this embodiment, the reformer 120 can be efficiently heated with the exhaust gas.

  In the present embodiment, the through hole 120b of the reformer 120 and the exhaust port 111 of the module case 8 are formed so as to at least partially overlap each other when viewed from above. More preferably, the exhaust port 111 is disposed at the center in the longitudinal direction and the width direction of the through hole 120b, which is a point-symmetrical position of the through hole 120b in a top view. Further, the exhaust port 111 and the through hole 120b are arranged in the central portion of the fuel cell assembly 12 in a top view.

  If the exhaust port 111 is disposed so as to be shifted in the width direction with respect to the through hole 120b in a top view, the flow of exhaust gas from the through hole 120b to the exhaust port 111 is uneven at least in the width direction. Or it becomes asymmetric. And with such an exhaust gas flow, the flow of power generation air also becomes uneven in the width direction. However, in the present embodiment, since the exhaust port 111 and the through hole 120b are arranged in the center portion of the module case 8 in a top view and overlap each other, the exhaust gas from the through hole 120b to the exhaust port 111 is used. The flow of air is uniform at least in the width direction, and the flow of power generation air is also uniform in the width direction. The reformer 120 is also disposed at the center position of the module case 8 in a top view. Thereby, the bias of the flow distribution of the power generation air is suppressed, and the power generation air can be sufficiently supplied to the fuel cell unit 16 substantially including the central portion and the vicinity of both ends. Deterioration of the cell unit 16 can be suppressed.

  Further, in the present embodiment, the flow rate of the exhaust gas is symmetrical (line symmetric) in the width direction of the reformer 120, that is, the flow rates of the exhaust passages 173 on both sides of the through hole 120b are equal. The through-holes 120b are formed in line symmetry so as to divide the reformer 120 at least approximately equally in the width direction when viewed from above so that there is no bias in the path distribution. In the present embodiment, the through-holes 120b are formed in line symmetry so as to divide the reformer 120 substantially equally in the longitudinal direction when viewed from above.

  In the present embodiment, as shown in FIGS. 11 and 12, the through-hole 120b of the reformer 120 is substantially oval when viewed from above, and is formed to extend in the longitudinal direction. The housing of the reformer 120 includes an upper case 121 and a lower case 122. Each of the upper case 121 and the lower case 122 is formed with connecting recesses 121a and 122a that are recessed inward so as to connect the through holes 120b from both ends in the width direction. In the present embodiment, the connecting recesses 121a and 122a are formed two by two apart from each other in the longitudinal direction.

  When the exhaust gas rising from the combustion chamber 18 collides with the bottom surface of the lower case 122 of the reformer 120, the connection recess 122 a causes the exhaust gas to flow on both sides in the width direction, that is, through-holes 120 b (exhaust passage 174) and The module case 8 is guided to the exhaust passage 173 along the side plate 8b. Thereby, in this embodiment, it becomes possible to supply exhaust gas to the through-hole 120b positively without the flow of exhaust gas being biased to the exhaust passage 173.

  Further, the connecting recesses 121 a and 122 a protrude toward the internal space of the reformer 120. Specifically, the connecting recesses 121a and 122a protrude toward the internal space so as to narrow the flow path of the reforming unit 120B in the reformer 120. For this reason, since the mixed gas flows through the reforming section 120B while changing the flow path by the protruding portions by the connecting recesses 121a and 122a, the contact opportunity and the contact time between the mixed gas and the reforming catalyst increase. Thereby, in this embodiment, the reforming efficiency of mixed gas can be improved. Further, the reforming catalyst is heated to a predetermined temperature by the exhaust gas flowing around the reformer 120, but the temperature of the reforming catalyst is increased by increasing the contact opportunity / time of contact between the mixed gas and the reforming catalyst. Thus, the mixed gas can be efficiently heated.

  In the present embodiment, the upper case 121 and the lower case 122 are formed from the same original case member. That is, the original case member is formed by molding (for example, drawing) a metal material using a predetermined mold. And the upper case 121 and the lower case 122 are each formed by processing the same original case member. For this reason, it is possible to achieve both cost reduction and improvement in assembly. Further, if the case of the reformer 120 is configured as one part, a bulky case cannot be formed by drawing, but in this embodiment, the case of the reformer 120 is configured as a two-part structure including an upper case 121 and a lower case 122. Therefore, a bulky case can be formed. For this reason, when the volumes are the same, a small reformer with a smaller bottom area can be obtained.

  Upper case 121 and lower case 122 have flange portions 121b and 122b on the outer peripheral side and flange portions 121c and 122c on the inner peripheral side that form through holes 120b, respectively, and these flange portions are superposed. It is fixed by welding. The outer peripheral flange portions 121b and 122b have the same width and can be easily welded from the side of the case. On the other hand, when the flange portions 121c and 122c on the inner peripheral side have the same width, it is difficult to perform the welding work from the side, and the assemblability is poor. For this reason, in this embodiment, the flange part 121c on the inner peripheral side is processed from the original case member so that the width is narrower than the flange part 122c (see FIG. 12). For this reason, the flange portions 121c and 122c can be easily welded from the upper side using the steps of the flange portions, and the assemblability can be improved.

  Further, the upper case 121 and the lower case 122 are curved so that the corners of the inner side surfaces (including the corners of the through holes 120b) have an R shape having a predetermined radius of curvature (see FIG. 11 and the broken line part A in FIG. 10). The radius of curvature is preferably 1.0 mm to 30 mm. For this reason, in this embodiment, when the gas passes through the inside of the reformer 120, the gas is prevented from staying in the corner portion, so that there is no dead space in the container and the gas is uniform with respect to the reforming catalyst. It becomes easy to circulate gas.

  Further, the connecting portion or corner portion between the peripheral surface of the through hole 120b and the lower surface of the lower case 122 has an R shape so as to have a predetermined radius of curvature over the periphery of the through hole 120b (including the portion of the coupling recess 122a). (See broken line portion A in FIG. 12). That is, as shown in FIG. 13, the case cross section of the reformer 120 has an R shape that is convex outward from the bottom surface of the reformer 120 to the peripheral surface (side surface) of the through hole 120b. It has become.

  Since the corners of the peripheral surface of the through hole 120b and the bottom surface of the lower case 122 are formed in a cross-sectional arc shape with a predetermined radius of curvature, the exhaust gas colliding with the lower case 122 is directed toward the through hole 120b. It becomes easy to be induced. Then, the air for power generation is also guided toward the through hole 120b by being pulled by the flow of the exhaust gas. However, if the radius of curvature becomes too large, the amount of power generation air that is guided to the through-hole 120b becomes too large, and the amount of power generation air that passes through the outer periphery of the reformer 120 becomes too small. The flow path distribution of the power generation air becomes uneven.

  For this reason, in this embodiment, the curvature radius of the corner is set to 1.0 mm to 30 mm so that the flow rate ratio of the power generation air in the exhaust passage 173 and the exhaust passage 174 becomes an appropriate value. Thus, sufficient power generation air can be distributed to each of the fuel cell units 16 disposed in the central portion and the peripheral portion.

Next, the operation of the exhaust gas guiding member of the present embodiment will be described with reference to FIG.
In the present embodiment, the evaporator 140 is arranged outside the module case 8, and this arrangement prevents a local temperature drop (including a temperature drop of the exhaust gas) due to the evaporation heat of water in the module case 8. In addition, the heat exchange between the exhaust gas and the power generation air is performed more efficiently. Therefore, in the present embodiment, heat exchange is avoided at the side portion of the fuel cell unit 16, and substantial heat exchange is performed only at a limited portion near the top plate 8a of the module case 8. Is possible.

  For this reason, in the present embodiment, the air passage 161a and the exhaust passage 172 are formed above and below the top plate 8a, and substantial heat exchange is performed in this portion. However, when downsizing the apparatus, the area of the top plate 8a is also small, so there is a possibility that an area for sufficient heat exchange cannot be secured. Therefore, in this embodiment, a high heat exchange efficiency is achieved by maintaining the temperature difference between the exhaust gas at the inlet and the outlet of the exhaust passage 172 as large as possible.

  For this reason, in this embodiment, the exhaust gas guiding member 130 is employed. The exhaust gas guiding member 130 causes the exhaust gas rising through the through-hole 120b to collide with the convex step 131a protruding downward so as to face the through-hole 120b, and is directed in the width direction. It promptly guides to the exhaust gas inlet 172a. Thus, the exhaust gas is quickly guided toward the exhaust gas introduction port 172a without staying near the bottom surface of the exhaust gas guiding member 130.

  Since an exhaust passage 172 functioning as a heat exchange unit is formed in the upper part of the exhaust gas guiding member 130, the exhaust gas in the upper part of the exhaust gas guiding member 130 is at a lower temperature than the exhaust gas in the lower part. Therefore, if the exhaust gas stays in the exhaust passage 174 near the bottom surface of the exhaust gas guiding member 130, heat exchange occurs between the exhaust gas in the exhaust passage 172 via the exhaust gas guiding member 130, and the exhaust passage 174. There is a risk that the temperature of the exhaust gas in the inside will decrease. Further, the exhaust gas in the exhaust passage 174 may be deprived of heat through the upper surface of the reformer 120 and the lower surface of the exhaust gas guiding member 130. However, in the present embodiment, by providing the convex step portion 131a on the bottom surface of the exhaust gas guiding member 130, the high-temperature exhaust gas that has risen through the through-hole 120b of the reformer 120 is exhausted. Since it can be quickly guided to the side without staying near the bottom surface of the member 130, it is possible to reach the exhaust gas inlet 172a while maintaining a high temperature.

  Further, in the exhaust passage 172, exhaust gas flows from both end portions in the width direction (exhaust gas introduction port 172a which is an inlet of the exhaust passage 172) toward the central portion (particularly, the exhaust port 111 which is an outlet of the exhaust passage 172). At this time, since heat exchange with the power generation air is performed, the temperature of the exhaust gas in the vicinity of the recess 132a of the exhaust gas guiding member 130 (see the broken line portion A in FIG. 9) becomes the lowest. In particular, the temperature in the vicinity of the exhaust port 111 disposed in the central portion in the longitudinal direction of the recess 132a is the lowest. On the other hand, in the exhaust passage 174, the temperature above the through hole 120b of the reformer 120, that is, in the vicinity of the convex step portion 131a of the exhaust gas guiding member 130 (see the broken line portion B in FIG. 9) is the highest.

  Since the region of the broken line portion A having the lowest temperature and the region of the broken line portion B having the highest temperature (see FIG. 9) are positioned above and below via the exhaust gas guiding member 130, the linear separation distance is small. For this reason, if heat exchange is performed between these regions, the exhaust gas inlet temperature may be lowered. Therefore, in the present embodiment, a gas reservoir 135 (gas chamber) is formed in the case member of the exhaust gas guiding member 130, and this gas reservoir 135 functions as a heat insulating material. Accordingly, in the present embodiment, heat exchange between the upper and lower spaces of the exhaust gas guiding member 130 (that is, the exhaust passage 172 and the exhaust passage 174), in particular, between the regions of the broken lines A and B in FIG. Therefore, the temperature of the high-temperature exhaust gas that has risen through the through-hole 120b of the reformer 120 is prevented from lowering, and the exhaust gas is allowed to flow out to the exhaust gas inlet 172a while maintaining the high temperature state. Can be maintained at a high temperature.

Further, since the exhaust gas guiding member 130 functions as a heat insulating material, the exhaust gas heat in the exhaust passage 172 is suppressed from being taken away by the exhaust gas guiding member 130, and the exhaust gas in the exhaust passage 172 and the air passage 161a are suppressed. Heat exchange with the power generation air can be promoted.
Further, since the upper guide plate 132 of the exhaust gas guiding member 130 functions as a heat reflecting plate in the exhaust passage 172, the radiant heat from the upper guide plate 132 can be given to the exhaust gas and air. Thereby, in this embodiment, the higher heat exchange efficiency in a heat exchange part can be achieved.

  Further, the exhaust gas guiding member 130 is formed of a member having heat conductivity (for example, a metal material or the like), and itself conducts heat. Therefore, when the convex step 131 a is heated by the high temperature exhaust gas colliding with the convex step 131 a of the exhaust gas guiding member 130, the convex step 131 a moves to another part of the exhaust gas guiding member 130. The heat conduction cannot be completely cut off. For this reason, heat conduction to the upper surface of the exhaust gas guiding member 130 may also occur. Then, on the upper surface of the exhaust gas guiding member 130, the temperature difference between the upstream side and the downstream side of the exhaust passage 172 constituting the heat exchange part is reduced, which is disadvantageous for improving the heat exchange efficiency.

  Therefore, in the present embodiment, by forming the recess 132a in the downstream portion (that is, the central portion in the width direction) of the exhaust passage 172 where the exhaust gas temperature is the lowest among the upper surface of the exhaust gas guiding member 130, A portion through which a main flow portion of the exhaust gas passes in the exhaust passage 172 (a passage height position other than a portion where the concave portion 132a is formed, a height position where the plate fin 175 is located in FIG. 9) and the exhaust gas guiding member 130. The distance from the bottom surface of the recess 132a is increased. As a result, heat exchange between the exhaust gas and the exhaust gas guiding member 130 hardly occurs in the downstream portion of the exhaust passage 172, and heat conduction from the convex step portion 131a to the concave portion 132a is suppressed. That is, once the temperature of the concave portion 132a is increased by heat conduction, heat exchange with the exhaust gas hardly occurs in the vicinity of the concave portion 132a. Thereby, in this embodiment, the higher heat exchange efficiency in a heat exchange part can be achieved.

  The mixed gas supply pipe 112 is connected to the reformer 120 from the exhaust port 111 through the module case 8. For this reason, the mixed gas in the mixed gas supply pipe 112 can be preheated in the module case 8, but the heat of the exhaust gas is taken away by this preheating, which is disadvantageous for improving the heat exchange efficiency. Therefore, in the present embodiment, the mixed gas supply pipe 112 is disposed in the recess 132a of the exhaust gas guiding member 130 on the downstream side of the exhaust passage 172 where the temperature of the exhaust gas is the lowest, so that the heat exchange unit Instead of the high-temperature exhaust gas before the heat exchange, the mixed gas supply pipe 112 is heated by the low-temperature exhaust gas after the heat exchange. Thereby, it is suppressed that the heat | fever of exhaust gas is taken away excessively by the mixed gas supply pipe | tube 112, and the efficiency (heat exchange efficiency) which preheats mixed gas can be reduced.

  Next, with reference to FIGS. 14-19, the effect | action of the heat exchanger of this embodiment is demonstrated. FIG. 14 is a cross-sectional view of a heat exchange part of a solid oxide fuel cell device according to an embodiment of the present invention, and FIG. 15 is an explanatory view of a connection part between a top plate and an exhaust pipe of a module case. FIG. 16 is an explanatory view of a power generation air supply passage on the top plate of the module case, FIG. 17 is an explanatory view of an exhaust passage below the top plate of the module case, and FIG. 18 is a perspective view of a plate fin. FIG. 19 is an explanatory diagram of plate fins arranged between the side plate of the air passage cover and the side plate of the module case.

  As shown in FIG. 14, the air passage cover 160 is attached to the module case 8 at a position slightly deviated on one end side in the longitudinal direction (the right side in FIG. 14). Specifically, on the other end side in the longitudinal direction of the module case 8, the hydrogen desulfurizer hydrogen extraction pipe 65 extends upward through the top plate 8 a, but the air passage cover 160 is provided for the hydrodesulfurizer. The module case 8 is arranged so as to be shifted to one end side in the longitudinal direction while avoiding the hydrogen extraction pipe 65. Thereby, it is not necessary to provide the air passage cover 160 with a through hole for allowing the hydrogen desulfurizer hydrogen extraction pipe 65 to pass therethrough. Further, when the air passage cover 160 is provided with a through hole, it is necessary to fix the hydrogen extraction pipe 65 for the hydrodesulfurizer hermetically in the through hole by welding or the like, but such a complicated processing step is unnecessary. It becomes.

  Further, as shown in FIG. 14, an opening 165 is formed in an end central portion on one end side of the top plate 160 a of the air passage cover 160, and the flow path direction adjusting unit covers the opening 165. 164 is fixed. The power generation air that has flowed through the power generation air introduction pipe 74 is supplied to the air passage 161 a through the opening 165 via the flow path direction adjustment unit 164. At least the supply-side end of the power generation air introduction pipe 74 extends horizontally along the longitudinal direction of the top plate 160a of the air passage cover 160 (see FIG. 4). In the present embodiment, the supply side end of the power generation air introduction pipe 74 extends in parallel with the top plate 160a or the top plate 8a, but may be angled so that the tip side is lowered.

  The flow path direction adjustment part 164 has a substantially semicircular mounting part 164a for connecting the power generation air introduction pipe 74 and a convex flow path part 164b formed so as to protrude upward. It is attached so as to close the opening 165 of the top plate 160a. The convex flow path part 164b is a cover member whose cross section of a substantially semicircular shape gradually decreases in a similar manner along the traveling direction of the power generation air from the mounting part 164a, and forms an air flow path therein. . Accordingly, the inner air flow path has a lower upper surface and a smaller width toward the distal end side. Further, the lower portion of the convex flow passage portion 164b communicates with the air passage 161a through the opening portion 165.

  The air passage 161a formed under the top plate 160a is formed so that the width direction dimension and the longitudinal direction dimension are large, but the height of the passage is low. For this reason, the distance between the top plate 8a of the module case 8 and the top plate 160a of the air passage cover 160 (the height of the passage) is smaller than the diameter dimension of the power generation air introduction pipe 74. It is difficult to connect the pipe 74 to the air passage cover 160 at the height of the air passage 161a, and even if it can be connected, the pressure loss increases.

  Further, when the power generation air introduction pipe 74 is arranged so as to extend in the vertical direction and the power generation air is supplied into the air passage 161a from above through the opening 165, the power generation air collides with the lower surface of the air passage 161a. However, it becomes difficult to disperse toward the side passage space. For this reason, it becomes difficult to uniformly supply the power generation air to the entire area of the air passage 161a, and a portion where the heat exchange efficiency is locally reduced is generated, so that the heat exchange efficiency is lowered as a whole.

  Therefore, in this embodiment, the supply-side end portion of the power generation air introduction pipe 74 is connected to the top plate 160a of the air passage cover 160 via the flow path direction adjustment section 164. With this configuration, the flow path direction adjustment unit 164 can be assembled to the air passage cover 160 as a separate member, and the assembling property for connecting the power generation air introduction pipe 74 to the air passage cover 160 is improved. The Further, the flow path direction adjusting unit 164 can be assembled in advance to the air passage cover 160, and then the air passage cover 160 can be assembled to the module case 8.

  However, in this configuration, the power generation air introduction pipe 74 is positioned above the air passage 161a, and the power generation air introduction pipe 74 and the flow direction in the air passage 161a are substantially parallel in the longitudinal component. However, they are separated in the vertical direction. For this reason, the flow path direction adjustment unit 164 is formed so that the internal flow path height decreases as the distance from the supply side end of the power generation air introduction pipe 74 increases. As a result, the convex flow path portion 164b gradually changes the flow direction of the power generation air supplied from the power generation air introduction pipe 74 downward, and is gentle relative to the flow path direction of the air passage 161a. The power generation air can be sent out to the air passage 161a at an angle.

  Furthermore, the convex flow channel part 164b is formed so that the internal flow channel width becomes narrower in addition to the height of the internal flow channel being lowered as the distance from the supply side end of the power generation air introduction pipe 74 increases. (See FIG. 4). Accordingly, the convex flow path portion 164b has a flow path cross-sectional area that gradually decreases with respect to the traveling direction. For this reason, the air for power generation is gradually increased without receiving a large resistance in the flow path direction adjustment unit 164. As a result, the power generation air supplied from the one end side in the longitudinal direction of the air passage cover 160 to the other end side in the longitudinal direction of the air passage cover 160 can reach the entire area of the air passage 161a. The working air can be supplied evenly.

  In addition, when the flow path direction adjustment unit 164 is not used, the area of inflow from the power generation air introduction pipe 74 to the air passage 161a having a low flow path height is reduced, and thus the pressure loss is increased as described above. However, a large inflow area can be ensured by using the flow path direction adjustment unit 164. For this reason, in this embodiment, pressure loss can be reduced and the air for power generation can be smoothly supplied to the other end side in the longitudinal direction of the air passage cover 160 in the air passage 161a.

  In the air passage 161a, two air distribution members 166 are arranged substantially in parallel along the longitudinal direction of the module case 8 on both sides of the exhaust pipe 171 (see FIGS. 15 and 16). The plate fin 162 is disposed on the outer side in the width direction of the air passage 161a with respect to the air distribution member 166. Therefore, when the gas such as the plate fin 162 moves between the two air distribution members 166, the plate fin 162 moves. A space is formed in which no member (excluding the exhaust pipe 171) serving as the resistance is present.

  The air distribution member 166 is a long member extending so as to partition the air passage 161a over substantially the entire length range of the top plate 160a of the air passage cover 160 in the longitudinal direction. The air distribution member 166 has a large number of through-holes spaced apart in the longitudinal direction and formed at predetermined intervals, and the air passage 161a is communicated in the width direction by the through-holes (see FIG. 14). Further, the air distribution member 166 connects the top plate 8a and the top plate 160a (see FIG. 15).

  As shown in FIG. 16, the power generation air supplied via the flow path direction adjustment unit 164 is divided into two air distribution members 166 from one end side (the right side in FIG. 16) to the other end side of the air passage cover 160. Flowing between. Since there is no physical resistance like a plate fin between the two air distribution members 166, the power generation air supplied to the air passage 161a with the flow velocity increased by the flow direction adjusting unit 164 is the air passage. The other end of the cover 160 can be reached. The power generation air moves in the width direction through the through hole of the air distribution member 166.

  The power generation air that has passed through the through-holes of the air distribution member 166 is heat-exchanged with the exhaust gas through the plate fins 162, the top plate 8a, and the plate fins 175 in the exhaust passage 172, and the temperature is raised. . Thereafter, the power generation air reaches both ends in the width direction of the air passage 161a, and is injected into the power generation chamber 10 from the air outlet 8f formed in the side plate 8b of the module case 8 via the air passage 161b. .

  Of the four end sides of the top plate 160a of the air passage cover 160, the flow path direction adjustment unit 164 is different from the end side (side extending in the longitudinal direction) communicating with the air passage 161b (side extending in the width direction). ). For this reason, in this embodiment, by supplying power generation air along the longitudinal direction in the air passage 161a on the top plate 8a while supplying it in the width direction, the air passage 161b on the side plate 8b is thereafter supplied. Power generation air can be supplied evenly in the longitudinal direction.

  In the present embodiment, the air passages 161a and 161b can be easily formed outside the module case 8 by assembling and fixing the air passage cover 160 from the outside of the module case 8 (see FIG. 4). In addition, it is possible to arrange the air passage cover 160 after arranging the plate fins 162 and 163 in advance on the top plate 8a and the side plate 8b of the module case 8, and the assembling property of the plate fins 162 and 163 is also good. .

Further, since the air passage cover 160 can be fixed to the module case 8 by applying mechanical welding from the outside, mass production can be achieved. In particular, in this embodiment, since the air passage cover 160 includes both the rectangular top plate 160a and the side plate 160b, the outer shape is formed linearly and it is easy to apply welding by an automatic machine.
Thus, in this embodiment, the workability for forming the air passage is improved, and the manufacturing cost can be reduced.

  Further, in the present embodiment, it is only necessary to form an exhaust passage in the module case 8, so that the manufacture is facilitated. Furthermore, since the exhaust passage is located in the module case 8, it is possible to prevent the exhaust gas from leaking out of the module case 8. On the other hand, the air passage is located outside the module case 8, but even when the airtightness of the air passage cannot be ensured, the power generation air can only be leaked out of the module case 8.

  In the present embodiment, as shown in FIG. 15, an exhaust pipe 171 is fixed to the exhaust port 111 of the top plate 8 a of the module case 8. For this reason, since the air passage cover 160 can be positioned with respect to the module case 8 by inserting the exhaust pipe 171 into the opening 167 of the air passage cover 160, good assemblability can be ensured. .

Further, the opening 167 of the air passage cover 160 is formed with an annular portion 167a by being curved so that the peripheral edge protrudes upward. Therefore, the exhaust pipe 171 can be easily inserted into the opening 167 along the curved surface of the annular portion 167a.
Further, when the annular portion 167a and the exhaust pipe 171 are fixed, the annular portion 167a becomes a margin for welding. For this reason, in this embodiment, the opening 167 of the air passage cover 160 and the peripheral surface of the exhaust pipe 171 can be more reliably fixed by welding as compared with the case where there is no connection allowance like the annular portion 167a. .
As described above, in the present embodiment, by providing the opening 167 with the annular portion 167a protruding upward, the workability when the air passage cover 160 is assembled to the module case 8 can be improved.

  In the present embodiment, as described above, heat exchange at the side portion of the fuel cell unit 16 is avoided, and substantial heat exchange is performed in the vicinity of the top plate 8a of the module case 8. . In this case, since the area of the top plate 8a is smaller than the area of the side plate 8b on the side of the fuel cell unit 16, there is a possibility that an area for sufficient heat exchange cannot be secured. However, in this embodiment, a heat exchange distance extending member 176 is provided in addition to the exhaust gas guiding member 130 described above so that sufficient heat exchange can be performed even in a small area.

  As shown in FIG. 17, on the upper guide plate 132 of the exhaust gas guide member 130, plate fins 175 are arranged on both sides in the width direction with the mixed gas supply pipe 112 and the recess 132a interposed therebetween. In addition, a heat exchange distance extending member 176 is disposed on the inner side of the plate fins 175 along the center side edge extending in the longitudinal direction. The two heat exchange distance extending members 176 are disposed substantially parallel to the longitudinal direction and symmetrical to the exhaust port 111. The heat exchange distance extending member 176 is a long plate-like member whose length is substantially half of the length in the longitudinal direction of the top plate 8a. The lower end portion of the heat exchange distance extending member 176 is fixed to the upper guide plate 132 and the upper end portion. Is in contact with the top plate 8a (see FIG. 15).

  The exhaust gas supplied from the exhaust passages 173 and 174 to the exhaust passage 172 via the exhaust gas introduction port 172a is exhausted from the exhaust port 111 provided in the substantially central portion of the top plate 8a. Therefore, when there is no heat exchange distance extending member 176, the flow of the exhaust gas is directed directly from the exhaust gas introduction port 172a to the exhaust port 111, and the exhaust gas flow is partly in the exhaust passage 172. It is biased and a sufficient amount of heat cannot be transmitted from the exhaust gas to the plate fins 175. As a result, heat exchange between the exhaust gas and power generation air cannot be performed sufficiently.

  Therefore, in the present embodiment, the two heat exchange distance extending members 176 are arranged with the exhaust port 111 interposed therebetween, so that the exhaust gas is bypassed and guided to the exhaust port 111. Specifically, the exhaust gas moves toward the central portion in the width direction of the exhaust passage 172 while passing through the plate fin 175 from the exhaust gas inlet 172a. However, since the heat exchange distance extending member 176 is disposed along the longitudinal direction on both sides of the exhaust port 111, the exhaust gas collides with the heat exchange distance extending member 176, and one end side or the other end in the longitudinal direction. It detours to the side and reaches the space between the two heat exchange distance extending members 176, and further passes through this space to reach the exhaust port 111. As described above, in the present embodiment, by bypassing the heat exchange distance extending member 176 for the exhaust gas, the distance in which the exhaust gas flows in the exhaust passage 172 is extended, and heat exchange is possible over the entire surface of the exhaust passage 172. Become. As a result, a sufficient amount of heat can be transferred from the exhaust gas to the power generation air in the air passage 161a, and as a result, the heat exchange efficiency between the exhaust gas and the power generation air can be improved.

Further, since the upper end portion of the heat exchange distance extending member 176 is in contact with the top plate 8a (see FIG. 15), the heat of the exhaust gas is directly conducted to the top plate 8a, so that the inside of the air passage 161a. The power generation air can be heated.
Furthermore, since the power generation air supplied to the air passage 161a collides with the outer peripheral wall of the exhaust pipe 171, the air density is higher in the vicinity of the exhaust pipe 171 than in other regions (the broken line portion A in FIG. 15). The exhaust pipe 171 is cooled. On the other hand, the upper end portion of the heat exchange distance extending member 176 is in contact with the top plate 8a in the vicinity of the exhaust pipe 171 (and the exhaust port 111) (see FIGS. 15 and 17). For this reason, since heat conduction from the heat exchange distance extending member 176 to the exhaust pipe 171 whose temperature has been lowered is promoted, it is possible to more efficiently raise the temperature of power generation air in the air passage 161a.

  Next, as shown in FIG. 18, the plate fins 162, 163, 175 are formed by pressing a rectangular thin metal plate, and are formed at a predetermined interval between the flat surface portion 200 and the flat surface portion 200. , And a protruding portion 202 that protrudes toward both sides of the flat surface portion 200. The protruding portion 202 is formed by cutting out a part of the flat surface portion 200 and expanding it into a trapezoidal shape, and includes an inclined portion 202a and a top plate portion 202b. The inclined portion 202a and the top plate portion 202b of the protruding portion 202 are separated from the flat surface portion 200, and an opening 202c is formed at a separated portion. In the plate fin formed in this way, when the gas flows along both side surfaces of the flat portion 200, the gas collides with the protruding portion 202 in addition to the direct heat exchange between the gas and the flat portion 200. As a result, the gas and the protrusion 202 exchange heat. Thereby, heat exchange can be performed efficiently between the gas and the plate fin.

  Further, the gas flow direction is changed by the collision between the gas and the protruding portion 202. Specifically, the gas flow path is changed to the side by colliding with the outer surface (surface opposite to the opening 202c) or the inner surface (surface on the opening 202c side) of the inclined portion 202a of the protrusion 202. The As a result, the gas flows in the direction along the flow path as a whole, but locally flows in various directions and mixes with each other, thereby improving dispersibility.

  As shown in FIG. 19, the plate fins 163 are disposed between the side plate 8 b of the module case 8 and the side plate 160 b of the air passage cover 160. The plate fin 163 is in contact with the side plate 8b at the top plate portion 202b of the protruding portion 202, but is in contact with the side plate 160b through a projection 203 provided on the top plate portion 202b.

  The projecting portion 203 is formed so as to have a smaller contact area than the top plate portion 202b. For example, the projecting portion 203 can be formed by projecting a part of the top plate portion 202b outward. Further, the protruding portion 203 can be a separate member from the plate fin having good thermal conductivity. In this case, it is preferable to form with a material having lower thermal conductivity than the plate fin.

  The protrusions 203 are not provided on the top plates 202b of all the protrusions 202 on the side plate 160b side, but are provided on at least one top plate 202b. For this reason, among the protrusions 202 protruding toward the side plate 160b, most of the protrusions 202 do not contact the side plate 160b, and only one or a few of the protrusions 202 contact the side plate 160b via the protrusions 203. ing.

  As described above, the plate fin 163 is in contact with the side plate 160b through the protrusion 203 having a small contact area and preferably low thermal conductivity. For this reason, it becomes possible to suppress heat dissipation (heat loss) from the plate fin 163 to the external heat insulating material 7 through the side plate 160b, and the exhaust gas in the exhaust passage 173 and the power generation air in the air passage 161b The heat exchange efficiency can be improved. The same applies to the plate fins 162.

DESCRIPTION OF SYMBOLS 1 Solid oxide fuel cell apparatus 2 Fuel cell module 7, 7a Heat insulating material 8 Module case 8a Top plate 8b Side plate 8d, 8e Closed side plate 10 Power generation chamber 16 Fuel cell unit 18 Combustion chamber (combustion part)
63 Fuel supply pipe 64 Fuel gas supply pipe (fuel gas supply passage)
74 Air introduction pipe for power generation 82 Exhaust gas discharge pipe 111 Exhaust port 112 Mixed gas supply pipe 120 Reformer 120b Through hole (opening)
121 Upper case 122 Lower case 121a, 122a Connecting recess 130 Exhaust gas guide member 131 Lower guide plate 131a Convex step 132 Upper guide plate 132a Recess 133, 134 Connection plate 135 Gas reservoir 140 Evaporator 160 Air passage cover 160a Top plate 160b Side plates 161a, 161b Air passages 162, 163 Plate fins 164 Flow direction adjustment unit 171 Exhaust pipe 172a Exhaust gas inlets 172, 173, 174 Exhaust passage 175 Plate fins 176 Heat exchange distance extending member

Claims (5)

In a solid oxide fuel cell device including a fuel cell unit that generates power by reaction of fuel gas obtained by reforming a raw material gas and air,
Module case,
A heat insulating material provided to cover the module case;
A fuel gas supply passage for supplying fuel gas to the fuel cell unit;
A reformer disposed in the module case, reforming a raw material gas using water vapor to generate a fuel gas, and supplying the fuel gas to the fuel gas supply passage;
A combustion section that burns fuel gas that did not contribute to power generation of the fuel cell unit and heats the reformer with the generated exhaust gas;
An evaporator disposed inside the heat insulating material outside the module case, evaporating water by heat exchange with exhaust gas, and supplying the generated water vapor to the reformer;
An air passage for supplying air to the fuel cell unit, formed at least between the top plate and side plate of the module case and the heat insulating material, and along the outer surface of the side plate of the module case. The air passage for flowing air from above to below;
An exhaust passage that is provided inside the module case and allows exhaust gas to flow out from an exhaust port, extends along the air passage across the top plate of the module case, and air that flows through the air passage; The exhaust passage is configured to perform heat exchange with the exhaust gas flowing through the exhaust passage via the top plate of the module case, and
The reformer has an opening through which exhaust gas generated in the combustion section passes from below to above,
An exhaust gas guiding member extending in a horizontal direction so as to cover the combustion part is disposed above the reformer,
The exhaust gas guiding member is provided with a convex step portion projecting downward on the bottom surface so as to face the opening portion, and the convex step portion passes through the opening portion from the combustion portion. A solid oxide fuel cell device characterized by guiding exhaust gas rising to the exhaust passage.   The exhaust gas guiding member is a case member that forms an internal space that communicates with the combustion section, and a space above the exhaust gas guiding member constitutes the exhaust passage. Solid oxide fuel cell device.   The solid oxide fuel cell device according to claim 2, wherein the exhaust passage is formed by an upper surface of the exhaust gas guiding member and a top plate of the module case.   The exhaust gas guide member is formed of a heat conductive member, and a concave portion recessed downward is formed in a portion of the upper surface of the exhaust gas guide member on the downstream side of the exhaust passage. The solid oxide fuel cell device according to claim 3. Further comprising a mixed gas supply pipe for supplying a mixed gas containing a raw material gas and water vapor to the reformer;
5. The solid oxide fuel cell device according to claim 4, wherein the mixed gas supply pipe is connected to the reformer after extending in a recess of the exhaust gas guiding member.

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