JP2017183133A - Solid oxide fuel cell device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel cell device capable of reducing thermal effect of a catalyst combustor on a module case, while furthermore capable of cooling down the catalyst combustor rapidly upon shutdown.SOLUTION: A solid oxide fuel cell device includes a module case 8 for housing a fuel cell unit 12, a combustion section 18 for generating exhaust gas by combusting off-gas from the fuel cell unit 12, a reformer 120 for reforming a material gas by heating with the exhaust gas and generating fuel gas, and a catalyst combustor 200 provided on the outside of the module case 8, and oxidizing unburned gas contained in the exhaust gas. The catalyst combustor 200 includes a honeycomb combustion catalyst 206, in which multiple internal flow paths extending in the horizontal direction and distributing exhaust gas are formed, and that extends in the direction where the exhaust gas distributes. The catalyst combustor 200 is located above the reformer 120.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a solid oxide fuel cell device, and more particularly to a solid oxide fuel cell including a plurality of fuel cells that generate power using fuel gas and oxidant gas.

  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.

  In the solid oxide fuel cell device, in the combustion section provided in the module case, off gas from the fuel cell is burned to generate high-temperature exhaust gas, and steam is generated by heat exchange with the exhaust gas in the evaporator, In the reformer provided in the module case, the raw material gas is reformed with steam by the heat of the exhaust gas to generate fuel gas. The exhaust gas discharged from the reformer is discharged to the outside after unburned gas such as carbon monoxide is burned in the combustion catalyst.

  As a fuel cell device provided with such a catalyst device, for example, in Patent Document 1, a fuel cell stack, an evaporator (vaporizer), and a reformer are accommodated in a fuel cell housing, and platinum A fuel cell device having a configuration in which a combustion catalyst comprising a noble metal fuel catalyst such as palladium or palladium or a base metal fuel catalyst such as manganese or iron is provided in a second carburetor is disclosed. However, although it is disclosed in Patent Document 1 that the inside of the second carburetor having the combustion catalyst is provided outside the fuel cell housing, the specific configuration (shape) of the combustion catalyst and the specific configuration of the combustion catalyst are disclosed. No specific arrangement is disclosed.

  Further, Patent Document 2 relates to a combustion catalyst used for reforming fuel in a fuel cell device, and in order to raise the temperature of the combustion catalyst in a short time, three flow paths are provided in the honeycomb-shaped combustion catalyst. There is disclosed a configuration in which switching is possible between a steady operation mode in which an inert gas is circulated in parallel through the three flow paths and a start mode in which the three flow paths are circulated in order. However, Patent Document 2 does not disclose the arrangement of the combustion catalyst with respect to other devices such as a module case and a reformer.

  Further, Patent Document 3 relates to a combustion catalyst used for reforming fuel in a polymer electrolyte fuel cell (PEFC), and in order to improve the catalyst performance, the combustion catalyst layer and the reforming catalyst layer are cylindrical. The honeycomb catalyst is used, and the combustion catalyst layer is divided into a plurality of parts, and a gap is provided between the combustion catalyst layer and the reforming catalyst layer. However, Patent Document 3 does not disclose the arrangement of the combustion catalyst with respect to other devices such as a module case and a reformer.

JP 2014-123576 A JP 2001-33011 A JP 2006-327904 A

  Here, although the combustion catalyst generates heat, the temperature of the combustion catalyst is about 100 to 500 ° C., which is lower than the operating temperature of 700 ° C. in the module case housing the fuel cell and the reformer. For this reason, the heat in the module case may be taken away by the combustion catalyst. In particular, in recent years, there has been an increasing need for household fuel cell devices, and miniaturization of fuel cell devices is desired. However, when the apparatus is downsized, the combustion catalyst device and the module case become closer to each other, so that the thermal influence on the module case by the combustion catalyst device becomes larger. Further, in general, a fuel catalyst device is configured by filling a plurality of spherical catalysts into the catalyst device, but the flow path filled with the catalyst has a large pressure loss, and it is difficult for cooling air to flow when the operation is stopped. Early temperature drop is impeded.

  The present invention has been made in view of the above problems, and an object of the present invention is to reduce the influence of heat on the module case of the combustion catalyst device, and to further reduce the temperature of the combustion catalyst device quickly when the operation is stopped. It is to provide a battery device.

  The present invention relates to a solid oxide fuel cell device including a plurality of fuel cells that generate power using fuel gas and oxidant gas, a module container that houses the fuel cells, and a fuel in the module container Above the battery cell, it is provided above the combustion part that burns off-gas from the fuel battery cell to generate exhaust gas, and above the combustion part in the module container, and is heated by the exhaust gas to reform the raw material gas, thereby fuel gas A reformer that generates water and an exhaust gas that is provided outside the module container, is supplied with exhaust gas discharged from the module container, generates steam by heat exchange with the exhaust gas, and supplies steam and raw material gas to the reformer Included in the exhaust gas after heat exchange exhausted from the evaporator, provided on the outside of the module container and inside the heat insulating material. A combustion catalyst that oxidizes the fuel, the combustion catalyst having a plurality of horizontally extending internal passages through which the exhaust gas flows, and a catalyst that extends in the direction in which the exhaust gas flows, and combustion The catalyst device is arranged to be positioned above the reformer.

  According to the present invention having the above-described configuration, a plurality of horizontally extending internal passages through which exhaust gas flows are formed, and a honeycomb type combustion catalyst extending in the direction in which exhaust gas flows is used. Since the honeycomb type combustion catalyst has a high cross-sectional aperture ratio, the pressure loss of the internal flow path through which the exhaust gas passes becomes extremely low, and the temperature can be quickly lowered when the operation is stopped. The "honeycomb-type" combustion catalyst in the present invention is not limited to a regular hexagonal shape (that is, a regular hexagonal column) arranged in a cross section in a cross section, To do.

In addition, since the combustion catalyst is positioned above the reformer and the internal flow path of the combustion catalyst extends in the horizontal direction, the combustion catalyst is separated from the fuel cell and the reformer. Thus, the thermal influence of the combustion catalyst on the module container can be reduced, the thermal stability in the module container can be improved, and the heat utilization efficiency can be improved.
Further, when a honeycomb type combustion catalyst is used, the pressure loss is reduced, while it is necessary to secure a sufficient flow path length of the internal flow path of the combustion catalyst. On the other hand, in the present invention, since the internal flow path extends in the horizontal direction, a sufficient flow path length can be ensured without affecting the module container.

  In addition, by providing an evaporator that absorbs heat from the fuel cell or reformer in the module container outside the module container, the thermal stability in the module container can be improved and the heat utilization efficiency can be improved. it can. Furthermore, by supplying the exhaust gas after heat exchange discharged from the evaporator to the combustion catalyst device, the exhaust heat of the exhaust gas can be used efficiently. Furthermore, since the combustion catalyst is provided inside the heat insulating material, heat exchange between the module container and the combustion catalyst can be further suppressed, and heat exchange between the combustion catalyst and the outside of the apparatus is suppressed. Thus, the temperature of the combustion catalyst can be maintained.

In the present invention, preferably, the evaporator has a heating device that heats at least the supplied exhaust gas, and the combustion catalyst is heated by the heat transfer from the heating device via the evaporator and / or by the heating device. Heated by the exhaust gas.
According to the present invention configured as described above, the combustion catalyst can be heated indirectly using the heater installed in the evaporator that supplies exhaust gas to the combustion catalyst device, and it is necessary to provide a separate heater in the combustion catalyst device The number of parts can be reduced.

In the present invention, preferably, the evaporator has an extending portion extending outward from the top surface of the module container in a top view, and the combustion catalyst is provided immediately below the extending portion of the evaporator. Yes.
According to the present invention configured as described above, it is possible to simultaneously reduce heat exchange between the module container and the combustion catalyst, heat the combustion catalyst by the heater of the evaporator, and reduce the size of the fuel cell device. it can.

In the present invention, preferably, the combustion catalyst is formed by winding up a sheet-like member in which a plurality of internal flow paths are arranged in parallel in a columnar shape.
According to the present invention having the above-described configuration, the number of turns of the sheet-like member is adjusted without changing the channel length of the internal channel by changing the pressure loss of the channel, the combustion efficiency of the combustion catalyst, and the outer diameter of the combustion catalyst. This can be easily changed.

In the present invention, preferably, the combustion catalyst device includes a cylindrical combustion catalyst container that houses the combustion catalyst, and a pair of annular fixing members that are provided inside the combustion catalyst container and have a diameter larger than the outer diameter of the combustion catalyst. The combustion catalyst is sandwiched and fixed by a pair of annular fixing members.
According to the present invention having the above-described configuration, the combustion catalyst is sandwiched and fixed by the pair of annular fixing members, so that the exhaust gas is prevented from passing through the gap between the combustion catalyst and the combustion catalyst container, and the exhaust catalyst is reliably supplied. The internal flow path can be circulated, and the combustion efficiency of the combustion catalyst can be improved.

In the present invention, preferably, the exhaust port for discharging the exhaust gas of the combustion catalyst device is provided above the reformer.
According to the present invention having the above-described configuration, the exhaust port for discharging the exhaust gas having a temperature lower than the internal temperature of the module container due to the release of heat by heat exchange is provided above the reformer. It is possible to prevent the reformer and the like from being cooled by the exhaust gas discharged from the discharge port.

  ADVANTAGE OF THE INVENTION According to this invention, the fuel cell apparatus which can reduce the thermal influence to the module case of a combustion catalyst device, and also can cool a combustion catalyst device at an early stage at the time of operation stop is provided.

1 is an overall configuration diagram showing a solid oxide fuel cell apparatus (SOFC) according to an embodiment of the present invention. It is side surface sectional drawing which shows the fuel cell module of the solid oxide fuel cell apparatus by one Embodiment of this invention. It is sectional drawing along the III-III line of FIG. It is a disassembled perspective view of a module case and an air passage cover. It is an expanded sectional view of the evaporator of the solid oxide fuel cell device shown in FIG. It is a perspective view of the state which abbreviate | omitted the top plate and combustion catalyst device of the evaporator of the solid oxide fuel cell apparatus shown in FIG. It is a figure which expands and shows a part of continuous groove | channel formed in the bottom face of the 1st container of the solid oxide fuel cell by one Embodiment of this invention. (A) is a perspective view which shows the plate fin provided in the exhaust gas flow path, (B) is a figure which expands and shows the vicinity of the plate fin in an evaporator. 1 is an axial sectional view of a combustion catalyst of a solid oxide fuel cell according to an embodiment of the present invention. It is a figure which shows the structure of the combustion catalyst of the solid oxide fuel cell by one Embodiment of this invention. 1 is a partial cross-sectional view showing a fuel cell unit of a solid oxide fuel cell according to an embodiment of the present invention. 1 is a perspective view showing a fuel cell stack of a solid oxide fuel cell according to an embodiment of the present invention. FIG. 3 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. FIG. 4 is a cross-sectional view taken along line III-III in FIG. 2, similar to FIG. 3. It is a perspective view which shows the flow of the water vapor | steam and raw fuel gas in the evaporation chamber and mixing chamber of the solid oxide fuel cell apparatus by one Embodiment of this invention. It is sectional drawing which expands and shows the vicinity of the 1st overlap part and 2nd overlap part of the solid oxide fuel cell apparatus by one Embodiment of this invention. It is a figure which shows the continuous groove | channel formed in the bottom face of the evaporation chamber by another embodiment.

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 container 8 (hereinafter referred to as “module case” as appropriate) is incorporated 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 (details will be described later in FIG. 11). The fuel cell stack 14 includes 16 fuel cells each including a fuel cell. It is composed of a cell unit 16 (details will be described later with reference to FIG. 12). In this example, the fuel cell assembly 12 has 128 fuel cell units 16. The housing 6 is not essential, and a frame that holds the heat insulating material 7 may be used. 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, the remaining fuel gas (off-gas) that has not been used for the power generation reaction and the remaining The air is combusted to generate 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 raw fuel gas (raw material gas) is disposed above the combustion chamber 18, and reaches a temperature at which the reformer 120 can undergo a reforming reaction by the combustion heat of the residual gas. So that it is heated.

  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 adjusts the flow rate of the water supplied from the pure water tank 26 that stores the water condensed from the moisture contained in the exhaust gas from the fuel cell module 2 and uses the filter to obtain pure water. A water flow rate adjusting unit 28 (such as a “water pump” driven by a motor) is provided. 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 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 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 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 through 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 a fuel cell module of a 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. 2 and 3, the housing is omitted.

  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. In addition, an opening 168 to which the power generation air introduction pipe 74 is connected is provided in a portion of the top plate 160a on the closed side plate 8d side. 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 is supplied into the air passage 161a from a power generation air introduction pipe 74 provided at a substantially central portion of the top plate 160a of the air passage cover 160 on the closed side plate 8d side of the module case 8 (FIG. 2). reference). 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. The evaporator 140 has an exhaust pipe 171 and a mixed gas supply pipe 112 connected to one side end side in the longitudinal direction (left-right direction in FIG. 2), and an exhaust gas discharge pipe 82 on the other side end side in the longitudinal direction. Are connected and supported by an exhaust pipe 171. A part 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 water supply pipe 62 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) and A raw material supply pipe 63 and an exhaust gas discharge pipe 82 (see FIG. 2) for discharging exhaust gas are connected, and an upper end portion of the exhaust pipe 171 is connected to the other end side 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.

FIG. 5 is an enlarged cross-sectional view of the evaporator of the solid oxide fuel cell device shown in FIG. FIG. 6 is a perspective view of the solid oxide fuel cell device shown in FIG. 2 with the top plate of the evaporator and the combustion catalyst device omitted. In addition, in FIG. 6, the flow of water (steam) and fuel (raw material gas) is shown with a continuous line and a dashed-dotted line, respectively.
The evaporator 140 has a substantially rectangular box-shaped evaporator case 141 (FIGS. 2 and 3) in a top view. The evaporator case 141 includes a first container 143, a second container 144 that is superimposed below the first container 143, and a top plate 142 that closes the top of the first container 143. Yes.

  The top plate 142 is made of a flat metal member. An opening for connecting the raw material supply pipe 63 is formed in the center in the width direction of one end of the top plate 142, and a water supply pipe 62 is connected to one side in the width direction of one end. An opening is formed.

  As shown in FIGS. 5 and 6, the first container 143 includes a bottom surface 143A1, 143A2, a side wall 143B extending upward from the outer peripheral edge of the bottom surface 143A1, 143A2, and a bowl extending horizontally outward from the upper end of the side wall 143B. 143C and the partition 147 are provided.

  The bottom surfaces 143A1 and 143A2 of the first container 143 are divided by a partition wall 147 into a first bottom surface 143A1 on the water supply pipe 62 and raw material supply pipe 63 side and a second bottom surface 143A2 on the mixed gas supply pipe 112 side. Yes. As will be described later, the first bottom surface 143A1 is the bottom surface of the evaporation chamber 150, and functions as an evaporation surface for exchanging heat between the exhaust gas and the water supplied from the water supply pipe 62. The upper surface of the bottom surface 143A1 of the first container 143 is formed as a rough surface having a surface roughness Ra of 1.5 μm or more. Thereby, the bottom surface 143A1 of the first container 143 has high hydrophilicity, and the water supplied on the bottom surface 143A1 spreads over a wide range. Furthermore, a continuous groove 156 as water diffusing means is formed on the upper surface of the bottom surface 143A1 of the first container 143.

  FIG. 7 is an enlarged view showing a part of the continuous groove formed on the bottom surface of the first container. Note that the lower side in FIG. 7 is the water supply pipe 62 side. As shown in the figure, on the first bottom surface 143A1 of the first container 143, square-shaped protrusions 156C are provided at equal intervals in the front-rear and left-right directions. Further, a cross-shaped protrusion 156D is formed at the center of four square-shaped protrusions 156C adjacent to the front, rear, left, and right. Accordingly, the continuous groove 156 is configured such that the square grooves 156A are arranged at equal intervals in the front, rear, left, and right, and the center portions of the opposing sides of the adjacent square grooves 156A are connected by the connection groove 156B. It has become.

  With such a configuration, for example, water that has entered the continuous groove 156 from the lower center of FIG. 7 is bent and divided to the left and right in the A portion, and straightly proceeds in the groove between the A portion and the B portion, and the B portion. Bend at. And the water bent in B part goes straight in the groove | channel between B part and C part, and is further bent and divided | segmented in C part. As described above, the water supplied to the continuous groove 156 is bent and divided in the A part, straightly moved in the groove between the A part and the B part, bent in the B part, and between the B part and the C part. By repeating the straight movement in the groove and the bending and branching in the C section, the flow spreads over a wide area.

  An opening is formed in the center of the second bottom surface 143A2 as an outlet of the mixing chamber 151, and the upper end of the mixed gas supply pipe 112 is connected to this opening. 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 the opening formed in the first container 143, and the other end is the top surface of the reformer 120. Are connected to the mixed gas supply port 120a. The mixed gas supply pipe 112 passes through the exhaust pipe 171 and extends vertically downward to the inside of the module case 8, where it is bent by approximately 90 °, extends horizontally along the top plate 8a, and then approximately 90 ° downward. It is bent and connected to the reformer 120.

  The partition wall 147 extends in the lateral direction between the side walls 143B extending in the longitudinal direction of the first container 143, and is formed by a metal material protruding upward. The partition wall 147 includes a pair of side walls 147B extending in parallel upward from the edges of the first and second bottom surfaces 143A1 and 143A2, and an upper surface 147C connecting the upper ends of the pair of side walls 147B. In addition, a recess 147A is formed in the center of the upper side of the partition wall 147 in the short direction (direction in which the partition wall 147 extends).

  As shown in FIGS. 5 and 6, the upper surface 147C of the partition wall 147 is formed as a flat surface and is flush with the flange portion 143C. Further, the width of the recess 147A is wider on the first bottom surface 143A1 side than on the second bottom surface 143A2 side, and gradually becomes narrower toward the second bottom surface 143A2 side. Further, the depth of the recess 147A from the upper surface 147C is smaller than the diameter of an alumina ball filled in the evaporation chamber 150 described later. A space 147D is formed inside the partition wall 147 by being surrounded by a pair of side walls 147B and an upper surface 147C, and the space 147D opens downward.

  The first container 143 is formed by press-molding a single metal member, and the bottom surfaces 143A1, 143A2, the side wall 143B, the flange portion 143C, and the partition wall 147 are configured as a continuous integral member. Yes.

  The first container 143 and the top plate 142 are joined in a state where the lower surface of the top plate 142 is in contact with the upper surface of the flange portion 143C and the upper surface 147C of the partition wall 147. The evaporation chamber 150 is defined by the top plate 142, the first bottom surface 143A1, the side wall 143B, and the partition wall 147 of the first container 143. In addition, the mixing chamber 151 is defined by the top plate 142, the second bottom surface 143 A 2, the side wall 143 B, and the partition wall 147 of the first container 143. The evaporation chamber 150 and the mixing chamber 151 are communicated with each other by a communication path that is partitioned by the concave portion 147A of the partition wall 147 and the top plate 142 and is located at the upper portion in the center of the evaporator 140 in the width direction.

  The evaporation chamber 150 is filled with a plurality of granular heat conductive members. As the thermally conductive member, for example, a spherical alumina ball or the like can be used. The alumina balls filled in the evaporation chamber 150 are in contact with the top plate 142.

  A partition member 152 is arranged in the mixing chamber 151. The partition member 152 is a member formed of a heat-resistant metal material that extends in the width direction in the same cross section. The partition member 152 includes an upper surface 152A, a pair of side wall portions 152B extending in parallel downward from both side portions of the upper surface 152A, and a pair of base portions 152C extending outward from the edges of the pair of side wall portions 152B. A horizontally long opening 152D is formed on both sides in the width direction of the side wall 152B on the evaporation chamber 150 side.

  The length in the longitudinal direction of the partition member 152 is substantially equal to the width of the mixing chamber 151. The partition member 152 is disposed in the evaporation chamber 150 so as to cover an opening (discharge port) to which the mixed gas supply pipe 112 formed on the second bottom surface 143A2 of the first container 143 is connected. In the state where the lower surface of the base portion 152C is in contact with the second bottom surface 143A2 of the first container 143, the partition member 152 is spot-welded between the base portion 152C and the second bottom surface 143A2, thereby the first container 143. It is fixed to. A gap is formed between the side portions of the pair of side wall portions 152B of the partition member 152 and the inner wall of the first container 143 without being welded. Further, the upper surface 152A of the partition member 152 has a height substantially equal to the flange portion 143C of the first container 143.

  By providing the partition member 152, the space in the evaporation chamber 150 is a second space between the first space 153 A between the partition wall 147 and the partition member 152 and the pair of side wall portions 152 B of the partition member 152. It is divided into 153B and a third space 153C between the partition member 152 and the side wall 143B of the first container 143. The first space 153A and the second space 153B communicate with each other through an opening 152D formed in the side wall 152B. In addition, the third space 153C includes the first space 153A and the second space 153B via a gap between both side portions of the pair of side wall portions 152B of the partition member 152 and the inner wall of the first container 143. Communicate. Since the area of this gap is much smaller than the area of the opening 152D formed in the side wall 152B, the pressure loss from the first space 153A to the third space 153C is increased from the first space 153A to the second space 153A. It is higher than the pressure loss up to the space 153B (particularly up to the opening formed on the bottom surface of the second bottom surface 143A2). As will be described later, the second space 153B functions as a mixing channel for mixing water vapor and the source gas, and the third space 153C functions as a bumping buffer space.

  The second container 144 includes a bottom surface 144A, a side wall 144B extending upward from the outer peripheral edge of the bottom surface 144A, and a flange 144C extending outward in the horizontal direction from the upper end of the side wall 144B. On the bottom surface 144A of the second container 144, an opening to which the upper end of the exhaust pipe 171 is connected and an opening to which the exhaust gas discharge pipe 82 is connected are formed.

  The second container 144 is superimposed on the first container 143 from below. In the overlapped state, the upper surface of the collar portion 144C of the second container 144 is in contact with the lower surface of the collar portion 143C of the first container 143. Further, the upper part of the side wall 144B of the second container 144 is in contact with the side wall 143B of the first container 143.

  Between the bottom surfaces 143A1 and 143A2 of the first container 143 and the bottom surface 144A of the second container 144, there is an exhaust gas passage 154 extending in the longitudinal direction of the evaporator 140 from the exhaust pipe 171 to the exhaust gas discharge pipe 82. Is formed. The exhaust gas passage 154 communicates with the space 147D in the partition wall 147.

  Further, a plate fin 155 as a heat exchange promoting member is provided in the exhaust gas passage 154. FIG. 8A is a perspective view showing a plate fin provided in the exhaust gas flow path, and FIG. 8B is an enlarged view showing the vicinity of the plate fin in the evaporator.

  The plate fin 155 is manufactured by processing a single metal plate. The plate fin 155 includes a plate-like main body 155A, a first protrusion 155B that protrudes downward, and a second protrusion 155C that protrudes upward.

  Each of the first projecting portions 155B includes a pair of inclined portions 155B1 extending obliquely downward and a connecting portion 155B2 connecting between the lower ends of the pair of inclined portions 155B1. And the 1st passage hole 155B3 is formed in the position which hits the upper part of the 1st protrusion part 155B of the main-body part 155A. In addition, a columnar protrusion 155B4 is formed on the lower surface of the connecting portion 155B2 of the first protrusion 155B. The area of the protrusion 155B4 is smaller than the areas of the connecting portions 155B2 and 155C2 of the first and second protrusions 155B and 155C.

  Each of the second projecting portions 155C includes a pair of inclined portions 155C1 extending obliquely upward, and a connecting portion 155C2 connecting between the upper ends of the pair of inclined portions 155C1. And the 2nd passage hole 155C3 is formed in the position which hits the downward direction of the 2nd protrusion part 155C of the main-body part 155A.

  In the plate fin 155, the protrusion 155B4 of the first protrusion 155B contacts the bottom surface 144A of the second container 144, and the connecting portion 155C2 of the second protrusion 155C contacts the bottom surface 143A1 of the first container 143. ing. Accordingly, the plate fin 155 is thermally connected to the bottom surface 143A1 of the first container 143, and the thermal resistance of the plate fin 155 to the bottom surface 144A of the second container 144 is the same as that of the bottom surface 143A1 of the first container 143. It is larger than the thermal resistance.

  By arranging the plate fins 155 in the exhaust gas flow path 154 in this way, the exhaust gas flow path 154 is divided into an upper space 154A and a lower space 154B by the main body portion 155A of the plate fin 155. Then, exhaust gas flowing through the exhaust gas passage 154 flows between the upper space 154A and the lower space 154B through the first passage hole 155B3 and the second passage hole 155C3 formed in the main body 155A of the plate fin 155. can do.

  As shown in FIG. 5, the distance between the bottom surface 143A1, 143A2 of the first container 143 and the top plate 142 is the distance between the bottom surface 144A of the second container 144 and the bottom surface 143A1, 143A2 of the first container 143. Is greater than the distance. Accordingly, the ratio of the height HA of the evaporation chamber 150 to the total height H of the evaporator 140 is higher than the ratio of the height HB of the exhaust gas passage 154 to the total height H of the evaporator 140. It has become.

  Further, the evaporator 140 includes a heater 157. As shown in FIG. 6, it is provided along the outer periphery of the three sides of the rectangular evaporator 140, and both end portions extend toward the evaporation chamber 150 side. As shown in FIG. 5, the heater 157 is in contact with the first overlapping portion 158 </ b> A where the side wall 143 </ b> B of the first container 143 and the side wall 144 </ b> B of the second container 144 overlap from the side. Further, the heater 157 is in contact with the second overlapping portion 158B where the flange portion 143C of the first container 143, the flange portion 144C of the second container 144, and the top plate 142 overlap from below. The heater 157 may be provided along the entire circumference of the evaporator 140.

  As shown in FIG. 5, the water supply pipe 62 and the raw material supply pipe 63 extend horizontally from the right side of FIG. 5 and straddle the side edge of the evaporator 140 on the evaporation chamber 150 side. The water supply pipe 62 and the raw material supply pipe 63 are bent downward and are inserted into the interior of the evaporation chamber 150 through the opening formed in the top plate 142. The water supply pipe 62 opens to the center in the width direction of the end portion on the evaporation chamber 150 side, and the raw material supply pipe 63 opens to one side in the width direction of the evaporation chamber 150 on the end portion on the evaporation chamber 150 side. Yes.

  The evaporator 140 includes a temperature sensor 69. Similarly to the water supply pipe 62 and the raw material supply pipe 63, the temperature sensor 69 extends in the horizontal direction across the side edge of the evaporator 140 on the evaporation chamber 150 side. The temperature sensor 69 is attached so as to contact the upper surface of the top plate 142. The temperature sensor 69 is arranged so that the sensor portion 69 </ b> A that detects the temperature at the tip of the temperature sensor 69 is located downstream of the middle of the evaporation chamber 150.

  The exhaust gas discharge pipe 82 is connected to one side in the width direction of the downstream end portion of the exhaust gas passage 154. The exhaust gas discharge pipe 82 connected to the evaporator 140 extends downward, and the lower end is connected to the combustion catalyst 200. The combustion catalyst 200 is a cylindrical member extending in the lateral direction, and a columnar space is formed therein. The exhaust gas discharge pipe 82 is connected to one end of the combustion catalyst 200, and the exhaust gas discharge pipe 202 is connected to the other end of the combustion catalyst 200. The exhaust gas discharge pipe 202 extends horizontally in a direction away from the evaporator 140 in the horizontal direction. Like the evaporator 140, the combustion catalyst 200 is disposed inside the heat insulating material 7.

  As shown in FIGS. 2 and 5, the evaporator 140 has an end portion on the side to which the exhaust gas discharge pipe 82 is connected extending outward from the edge of the module case 8 in a top view. The combustion catalyst device 200 is located immediately below the portion of the evaporator 140 that extends outward from the edge of the module case 8. The combustion catalyst device 200 is located above the reformer 120. The exhaust gas outlet of the combustion catalyst device 200 is provided at a position higher than the reformer 120, and the exhaust gas discharge pipe 202 connected to the exhaust gas outlet has a position higher than the reformer 120 in the horizontal direction. It extends.

  FIG. 9 is an axial sectional view of the combustion catalyst. As shown in the figure, the combustion catalyst device 200 includes a container main body 204, a combustion catalyst 206 disposed in the container main body 204, and a pair of annular fixing members disposed before and after the combustion catalyst 206 in the container main body 204. 208.

  The container main body 204 has a cylindrical shape and extends horizontally along the downstream edge of the exhaust gas passage 154 of the evaporator 140. Further, as shown in FIG. 2, the height of the lowermost portion of the container main body 204 is higher than the height of the uppermost portion of the reformer 120.

  The annular fixing member 208 has an annular shape, and the outer diameter of the annular fixing member 208 is larger than the diameter of the combustion catalyst 206. The annular fixing member 208 is fixed in a state of being fitted in the container main body 204.

  The combustion catalyst 206 has a cylindrical shape and is disposed in the container main body 204. The combustion catalyst 206 is fixed in the container main body 204 by being sandwiched from the front and rear by a pair of annular fixing members 208. FIG. 10 is a diagram showing the configuration of the combustion catalyst. As shown in the figure, the combustion catalyst 206 is constituted by winding up a sheet-like catalyst 210. The sheet-like catalyst 210 includes an intermediate material 210B extending in a zigzag manner between a pair of upper and lower surfaces 210A. A catalyst is applied to the surfaces of the upper and lower surfaces 210A and the intermediate material 210B. Thereby, the sheet-like catalyst 210 is configured such that triangular through holes 206A are continuously arranged between the upper and lower surfaces 210A. The combustion catalyst 206 in which the sheet-like catalyst 210 having such a configuration is wound has a configuration in which through-holes 206A having a triangular cross section in the longitudinal direction are continuously arranged in a spiral shape without a gap. In this specification, such a structure in which a plurality of through holes extend in parallel is referred to as a honeycomb type.

  In such an evaporator 140, the exhaust gas supplied from the exhaust pipe 171 flows through the exhaust gas passage 154 and is discharged to the exhaust gas discharge pipe 82. Then, the water supplied from the water supply pipe 62 to the evaporation chamber 150 flows while spreading on the bottom surface 143A1. Then, heat exchange is performed between the exhaust gas and water through the bottom surface 143A1, and the water evaporates to generate water vapor. The water vapor generated in the evaporation chamber 150 flows into the mixing chamber 151 together with the raw material gas supplied from the raw material supply pipe 63, and the water vapor and the fuel gas are mixed and discharged to the mixed gas supply pipe 112.

  Further, the exhaust gas discharged from the exhaust gas discharge pipe 82 is supplied to the combustion catalyst device 200. Exhaust gas supplied to the combustion catalyst device 200 passes through the internal flow path in the through hole 206A of the combustion catalyst 206, and toxic gas (unburned fuel) such as carbon monoxide is oxidized and discharged to the exhaust gas discharge pipe 202. The

  Next, as shown in FIGS. 2 and 3, the reformer 120 is disposed so as to extend in the horizontal direction along the longitudinal direction of the module case 8 above the combustion chamber 18, and the top plate 8 a of the module case 8. Between the top plate 8a and 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. 11 is a partial cross-sectional view showing a fuel cell unit of a solid oxide fuel cell according to an embodiment of the present invention.
As shown in FIG. 11, 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 is, for example, zirconia doped with at least one selected from rare earth elements such as Y and Sc, ceria doped with at least one selected from rare earth elements, lanthanum gallate doped with at least one selected from Sr and Mg, Formed from at least one of the following.

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

Next, the fuel cell stack 14 will be described with reference to FIG.
FIG. 12 is a perspective view showing a fuel cell stack of a solid oxide fuel cell according to an embodiment of the present invention.
As shown in FIG. 12, 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 by a rectangular lower support plate 68 made of ceramic (see FIG. 2) on the lower end side, and on the upper end side, two fuel cell unit 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, a gas flow in the fuel cell module of the solid oxide fuel cell device according to the embodiment of the present invention will be described with reference to FIGS.
13 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. 14 is similar to FIG. It is sectional drawing along the -III line. 13 and 14 are diagrams in which arrows indicating gas flows are newly added in FIGS. 2 and 3, respectively. 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 FIGS. 13 and 14, water and raw fuel gas (raw material gas) are supplied to the upper layer of the evaporator 140 from the water supply pipe 62 and the raw material supply pipe 63 connected to one end side in the longitudinal direction of the evaporator 140. It is supplied into the evaporation chamber 150 provided. The water supplied to the evaporation chamber 150 spreads over a wide range because the upper surface of the bottom surface 143A1 of the first container 143 is formed as a rough surface. Moreover, since the continuous groove | channel 156 is formed in the upper surface of bottom face 143A1 of the 1st container 143, it spreads in a wide range. The water spread in a wide range in this way is heated by the exhaust gas flowing through the exhaust gas flow path 154 provided in the lower layer of the evaporator 140 to become water vapor. At this time, since the evaporation chamber 150 is filled with alumina balls (heat conducting member), the heat from the exhaust gas passage 154 is transferred to the water through the alumina balls. The water vapor and the raw fuel gas supplied from the raw material supply pipe 63 flow in the evaporation chamber 150 in the downstream direction.

  FIG. 15 is a perspective view showing the flow of water vapor and raw fuel gas in the evaporation chamber and the mixing chamber. The water vapor and raw fuel gas generated in the evaporation chamber 150 pass through the recess 147 </ b> A formed in the center of the partition wall 147 and flow into the mixing chamber 151. At this time, since the concave portion 147A is narrowed toward the mixing chamber 151, the water vapor and the raw fuel gas are more uniformly mixed when passing through the concave portion 147A. At this time, since the exhaust gas enters the space 147D inside the partition wall 147, the water vapor and the raw fuel gas are heated by the partition wall 147. Then, the water vapor and raw fuel gas that have flowed into the first space 153A of the mixing chamber 151 from the recess 147A flow separately on both sides in the width direction. Here, as described above, the pressure loss from the first space 153A to the third space 153C between the partition member 152 and the inner wall of the mixing chamber 151 is caused by the first space 153A via the opening 152D. 15 is higher than the pressure loss from the first bottom surface 143A2 to the opening formed on the bottom surface of the second bottom surface 143A2, the water vapor and the raw fuel gas flowing into the first space 153A are indicated by solid lines in FIG. As described above, the air flows into the second space 153B through the opening 152D of the partition member 152. The water vapor and the raw fuel gas are mixed while flowing through the first space 153A and the second space 153B in this way, and discharged to the mixed gas supply pipe 112.

  When a bumping phenomenon occurs in the evaporation chamber 150, water vapor is suddenly generated in the evaporation chamber 150 and flows into the first space 153A. And when a bumping phenomenon arises in this way, the atmospheric pressure in the 1st space 153A of the evaporation chamber 150 and the mixing chamber 151 becomes high temporarily. Thus, when the atmospheric pressure in the first space 153A increases, the water vapor in the first space 153A passes through the gap between the side portion of the partition member 152 and the inner wall of the first container 143, and the third space 153C. Flow into. Thereby, even if a bumping phenomenon occurs, it is possible to suppress a rapid increase in pressure in the evaporation chamber 150 and the mixing chamber 151.

  FIG. 16 is an enlarged sectional view showing the vicinity of the first overlapping portion 158A and the second overlapping portion 158B. As shown in the figure, a heater 157 is disposed so as to contact the first overlapping portion 158A and the second overlapping portion 158B of the evaporator 140. For this reason, as indicated by the arrows in the figure, the heat from the heater 157 effectively prevents the bottom surface 143A2 of the first container 143 and the second container 144 from passing through the first overlapping portion 158A and the second overlapping portion 158B. The bottom surface 144A and the top plate 142 are heated. Thereby, the water vapor and source gas in the evaporation chamber 150 and the mixing chamber 151 are heated. Further, the exhaust gas in the exhaust gas flow path 154 is also heated, and this heat is transmitted to the water vapor and the raw material gas via the bottom surface 143A2 of the first container 143, so that the water vapor and the raw material gas are heated more efficiently. Can do.

  The mixed gas (fuel gas) discharged to the mixed gas supply pipe 112 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 vicinity of the exhaust gas passage 154, the exhaust pipe 171, and the exhaust passage 172 in order, the mixed gas in the mixed gas supply pipe 112 is caused by the exhaust gas flowing through these passages. Further heating.

  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 120 </ b> C into the fuel gas supply pipe 64 and the hydrodesulfurizer hydrogen extraction pipe 65. 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. 13 and 14, 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. 13, 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 in the horizontal direction through the exhaust passage 172, a plate fin 175 provided in the exhaust passage 172 and a plate fin 162 provided in the air passage 161a 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 and flows into the exhaust gas flow path 154 of the evaporator 140. The exhaust gas that has flowed into the exhaust gas flow path 154 flows through the exhaust gas flow path 154 toward the exhaust gas discharge pipe 82. At this time, since the plate fin 155 is provided in the exhaust gas passage 154, heat exchange between the exhaust gas and the water in the evaporation chamber 150 is performed more efficiently.

  Further, the exhaust gas passing through the exhaust gas passage 154 is heated by the heater 157. Heat from the heater 157 is transmitted to the combustion catalyst 200 through the evaporator 140 and the exhaust gas passage 154. Further, the exhaust gas is heated by the heater 157 in the exhaust gas passage 154, and the heated exhaust gas flows into the combustion catalyst device 200. In this way, the heat of the heater 157 is indirectly transmitted to the combustion catalyst device 200, and the combustion catalyst 206 can be heated.

  Then, the exhaust gas that has passed through the exhaust gas passage 154 is discharged to the exhaust gas discharge pipe 82 and flows into the combustion catalyst device 200. The exhaust gas flowing into the combustion catalyst device 200 passes through the through hole 206A of the combustion catalyst 206. As a result, unburned gas (toxic gas) such as carbon monoxide contained in the exhaust gas comes into contact with the catalyst and is oxidized. Then, the exhaust gas flowing through the combustion catalyst device 200 is discharged to the exhaust gas discharge pipe 202.

  In the above embodiment, the case where the continuous groove 156 as shown in FIG. 7 is formed on the bottom surface 143A1 of the evaporation chamber 150 has been described. However, the pattern of the continuous groove formed on the bottom surface 143A1 of the evaporation chamber 150 is described here. Not limited.

  FIG. 17 is a view showing a continuous groove 256 formed in the bottom surface 143A1 of the evaporation chamber 150 according to another embodiment. Note that the lower side in FIG. 17 is the water supply pipe 62 side. As shown in the figure, in this embodiment liquid, a regular hexagonal protrusion 256C is provided on the first bottom surface 143A1 of the first container 143. These protrusions 256C are arranged so that the sides of the adjacent protrusions 256C face each other in parallel, so that regular hexagonal grooves are formed in a mesh shape between the protrusions 256C. . With such a configuration, for example, water that has entered the groove 256 from the lower center of FIG. 17 is bent and divided to the left and right in the D portion, goes straight in the groove in the E portion, and is bent and divided again in the D portion. The Thus, the water supplied to the continuous groove 256 flows while spreading in a wide area by repeating the bending and division in the D portion and the straight advance in the groove of the E portion.

As described above, according to the above embodiments, the following effects can be obtained.
According to the embodiment, the honeycomb type combustion catalyst 206 extending in the direction in which the exhaust gas flows is used by forming a plurality of horizontally extending through holes 206A through which the exhaust gas flows. Since the honeycomb-type combustion catalyst 206 has a high cross-sectional aperture ratio, the pressure loss of the through hole 206A through which the exhaust gas passes becomes extremely low, and the temperature can be quickly lowered when the operation is stopped. In addition, since the combustion catalyst device 200 is positioned above the reformer 120 and the through-hole 206A of the combustion catalyst 206 extends in the horizontal direction, the combustion catalyst 206 can be used as the fuel cell assembly 12 or the like. It can be separated from the reformer 120, the thermal influence of the combustion catalyst 206 into the module case 8 can be reduced, the thermal stability in the module case 8 can be improved, and the heat utilization efficiency can be improved. Further, as in the present embodiment, when the honeycomb type combustion catalyst 206 is used, the pressure loss is reduced, but it is necessary to sufficiently secure the flow path length of the through hole 206A of the combustion catalyst 206. On the other hand, according to the embodiment, since the through hole 206A extends in the horizontal direction, a sufficient flow path length can be ensured without affecting the module case 8 in a thermal manner.

  According to the above embodiment, the evaporator 140 that absorbs heat from the fuel cell assembly 12 and the reformer 120 in the module case 8 is provided outside the module case 8, so that the thermal stability in the module case 8 is achieved. The heat utilization efficiency can be improved. Further, by supplying the exhaust gas after the heat exchange discharged from the evaporator 140 to the combustion catalyst device 200, the exhaust heat of the exhaust gas can be used efficiently. Furthermore, since the combustion catalyst device 200 is provided inside the heat insulating material 7, heat exchange between the module case 8 and the combustion catalyst device 200 can be further suppressed, and the combustion catalyst device 200 and the outside of the apparatus can be connected to each other. Therefore, the temperature of the combustion catalyst can be maintained.

  Further, according to the above-described embodiment, the combustion catalyst device 200 is heated from the heater 157 via the evaporator 140 and further heated by the exhaust gas heated by the heater 157 flowing in. Thus, according to the above embodiment, the combustion catalyst 206 can be heated by indirectly using the heater 157 installed in the evaporator 140 that supplies the exhaust gas to the combustion catalyst 200, and the combustion catalyst It is not necessary to separately provide a heater in 200, and the number of parts can be reduced.

  Further, the evaporator 140 has an extending portion extending outward from the top plate 8a of the module case 8 in a top view, and the combustion catalyst device 200 is provided immediately below the extending portion of the evaporator 140. Yes. Thereby, reduction of heat exchange between the module case 8 and the combustion catalyst device 200, heating of the combustion catalyst device 200 by the heater 157 of the evaporator 140, and miniaturization of the fuel cell device 1 can be achieved at the same time. it can.

  In the above-described embodiment, the combustion catalyst 206 is configured by winding up a sheet-like catalyst 210 in which a plurality of through-holes 206A are arranged in parallel in a columnar shape. Accordingly, by adjusting the number of turns of the sheet-like catalyst 210, the flow loss of the flow path, the combustion efficiency of the combustion catalyst, and the outer diameter of the combustion catalyst device can be easily achieved without changing the flow path length of the through hole 206A. Can be changed.

  According to the above-described embodiment, the combustion catalyst 206 is sandwiched and fixed by the pair of annular fixing members 208 to prevent the exhaust gas from passing through the gap between the combustion catalyst 206 and the container main body 204, and the exhaust gas is reliably burned. The through-hole 206A of the catalyst 206 can be circulated, and the combustion efficiency of the combustion catalyst 206 can be improved.

  According to the above embodiment, the exhaust port for discharging the exhaust gas of the combustion catalyst device 200 is provided so as to be positioned above the reformer 120. It is possible to prevent the reformer 120 and the like from being cooled by the exhaust gas discharged from the discharge port having a temperature lower than the internal temperature.

DESCRIPTION OF SYMBOLS 1 Solid oxide fuel cell apparatus 2 Fuel cell module 4 Auxiliary machine unit 6 Housing 7 Heat insulating material 8 Module case 8 Closed side plate 8a Top plate 8b Side plate 8c Bottom plate 8d Closed side plate 8e Closed side plate 8f Outlet 10 Power generation chamber 12 Fuel cell Assembly 13 Lower guide plate 14 Fuel cell stack 16 Fuel cell unit 18 Combustion chamber 24 Water supply source 26 Pure water tank 28 Water flow rate adjustment unit 30 Fuel supply source 32 Gas shutoff valve 36 Desulfurizer 38 Fuel flow rate adjustment unit 39 Valve 40 Air supply source 42 Solenoid valve 44 Reforming air flow rate adjustment unit 45 Power generation air flow rate adjustment unit 50 Hot water production device 52 Control box 54 Inverter 62 Water supply pipe 63 Raw material supply pipe 64 Fuel gas supply pipe 64a Horizontal portion 64b Fuel supply Hole 65 Hydrogen extraction pipe for hydrodesulfurizer 66 Manifold 8 Lower support plate 69 Temperature sensor 69A Sensor part 74 Power generation air introduction tube 82 Exhaust gas discharge tube 83 Ignition device 84 Fuel cell 86 Inner electrode terminal 88 Fuel gas flow channel 90 Inner electrode layer 90a Upper part 90b Outer peripheral surface 90c Upper end surface 92 Outer electrode layer 94 Electrolyte layer 96 Sealing material 98 Fuel gas passage narrow tube 100 Upper support plate 102 Current collector 102a Fuel electrode connection portion 102b Air electrode connection portion 104 External terminal 111 Exhaust port 112 Mixed gas supply tube 120 Reformer 120A Mixed gas receiving part 120B Reforming part 120C Gas discharge part 120a Mixed gas supply port 120b Through hole 121 Upper case 122 Lower case 123a Partition plate 123b Partition plate 130 Exhaust gas guide member 131 Lower guide plate 131a Convex step part 132 Upper part Guide plate 132a Recess 133 Connection plate 135 Gas reservoir 140 Steam Generator 141 Evaporator case 142 Top plate 143 First container 143A1 Bottom surface 143A2 Bottom surface 143B Side wall 143C Ridge part 144 Second container 144A Bottom surface 144B Side wall 144C Ridge part 147 Partition wall 147A Recessed part 147B Side wall 147C Upper surface 147D Space 150 Evaporating chamber 151 Chamber 152 Partition member 152A Upper surface 152B Side wall portion 152C Base portion 152D Opening portion 153A First space 153B Second space 153C Third space 154 Exhaust gas flow path 154A Upper space 154B Lower space 155 Plate fin 155A Main body portion 155B Protruding portion 155B1 Inclined portion 155B2 Connecting portion 155B3 Passing hole 155B4 Protruding portion 155C Projecting portion 155C1 Inclining portion 155C2 Connecting portion 155C3 Passing hole 156 Continuous groove 156A Square groove 156B Connecting groove 156C Protruding 156D Protruding portion 157 Heater 158A First overlapping portion 158B Second overlapping portion 160 Air passage cover 160a Top plate 160b Side plate 161a Air passage 161b Air passage 162 Plate fin 163 Plate fin 167 Opening portion 171 Exhaust pipe 172 Exhaust passage 172a Exhaust gas Inlet 173 Exhaust passage 174 Exhaust passage 175 Plate fin 200 Combustion catalyst device 202 Exhaust gas discharge pipe 204 Container body 206 Combustion catalyst 206A Through hole 208 Annular fixing member 210 Sheet-like catalyst 210A Upper and lower surfaces 210B Intermediate material 256 Continuous groove 256C Projection

Claims (6)

A solid oxide fuel cell device comprising a plurality of fuel cells that generate power with fuel gas and oxidant gas,
A module container for accommodating the fuel battery cell therein;
A combustion unit that burns off-gas from the fuel battery cell to generate exhaust gas above the fuel battery cell in the module container;
A reformer that is provided above the combustion section in the module container and is heated by the exhaust gas to reform the raw material gas to generate the fuel gas;
An evaporator that is provided outside the module container, is supplied with the exhaust gas discharged from the module container, generates steam by heat exchange with the exhaust gas, and supplies the steam and the raw material gas to the reformer When,
A heat insulating material covering the module container and the evaporator;
A combustion catalyst that is provided outside the module container and inside the heat insulating material and oxidizes unburned fuel contained in the exhaust gas after heat exchange discharged from the evaporator;
The combustion catalyst device includes a plurality of horizontally extending internal channels through which the exhaust gas flows, and a catalyst extending in the direction in which the exhaust gas flows,
The solid oxide fuel cell device, wherein the combustion catalyst is disposed above the reformer. The evaporator has a heating device that heats at least the supplied exhaust gas,
2. The solid oxide fuel cell device according to claim 1, wherein the combustion catalyst is heated by heat transfer from the heating device through the evaporator and / or exhaust gas heated by the heating device. The evaporator has an extending portion that extends outward from the top surface of the module container in a top view,
The solid oxide fuel cell device according to claim 2, wherein the combustion catalyst is provided immediately below the extending portion of the evaporator.   The solid oxide fuel cell device according to claim 3, wherein the combustion catalyst is formed by winding up a sheet-like member in which a plurality of internal flow paths are arranged in parallel in a cylindrical shape. The combustion catalyst device includes a cylindrical combustion catalyst container that houses the catalyst;
An annular fixing member provided inside the combustion catalyst container and having a diameter larger than the outer diameter of the catalyst,
The solid oxide fuel cell device according to claim 4, wherein the catalyst is fixed by the annular fixing member.   The solid oxide fuel cell device according to claim 3, wherein an exhaust port for discharging the exhaust gas of the combustion catalyst device is provided so as to be positioned above the reformer.

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