JP2014072026A - Solid oxide fuel cell device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solid oxide fuel cell device that feeds raw fuel gas into a reforming section without sending the raw fuel gas at high pressure.SOLUTION: A solid oxide fuel cell device (1) includes: a fuel supply device; a water supply device (28) that supplies water for steam reforming; an oxidant gas supply device (45); a fuel cell stack (14) that generates electric power; a combustion section (18) that burns fuel gas that is left without being used for electric power generation; a fuel gas supply passage (20) that is arranged so as to surround the fuel cell stack (14); a fuel gas introducing section (90a) that is provided in a lower portion of the fuel gas supply passage (20); a vaporization section (86) that is arranged above the fuel gas introducing section (90a) and that vaporizes water; and a reforming section (94) that is provided in the fuel gas supply passage (20) and that steam-reforms raw fuel gas by use of steam. The reforming section (94) is arranged above the vaporization section (86) so as to surround an upper portion of the fuel cell stack (14).

Description

  The present invention relates to a solid oxide fuel cell device, and more particularly, to a solid oxide fuel cell device that reforms a hydrocarbon-based raw fuel gas and generates electric power using the reformed fuel gas.

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

  Japanese Patent Laying-Open No. 2010-238600 (Patent Document 1) describes a solid oxide fuel cell. In this fuel cell, a box-shaped reformer is disposed above the fuel cell stack, and the reformer is heated by combustion heat that burns off-gas flowing out from the upper end of each cell of the fuel cell stack. doing. The reformer is supplied with raw fuel gas and water for steam reforming, and the mixture of the raw fuel gas and steam touches the reforming catalyst filled in the reformer, thereby The gas is steam reformed.

  In such a type of reformer, the raw fuel gas and the steam are fed into the reforming catalyst after flowing through a relatively long passage so that the supplied raw fuel gas and the steam are sufficiently mixed. . Further, the air-fuel mixture is reformed while flowing through a relatively long passage in the reformer so that the air-fuel mixture of the raw fuel gas and water vapor sufficiently contacts the reforming catalyst.

JP 2010-238600 A

  However, in the reformer in the fuel cell described in Japanese Patent Application Laid-Open No. 2010-238600, since the mixture of raw fuel gas and water vapor is reformed through a long channel, there is a problem that the pressure loss in the reformer is large. There is. For this reason, in order to pass the raw fuel gas to be reformed through the reformer, it is necessary to strongly pressurize the raw fuel gas and send it to the reformer.

  Further, in the fuel cell described in JP 2010-238600 A, the reformer is disposed above the fuel cell stack and is directly heated from below by the combustion heat of the off gas flowing out from each cell. There is a problem in that the occupied projection area of the mass device becomes large. That is, in order to reform a certain amount of raw fuel gas, a predetermined volume of the reforming catalyst is required. In order to directly heat the predetermined volume of the reforming catalyst evenly by the combustion heat of off-gas. In this case, the reforming catalyst needs to be distributed in a thin and wide area above the fuel cell stack, so that the projected area occupied by the reformer increases.

Accordingly, an object of the present invention is to provide a solid oxide fuel cell device that can feed raw fuel gas into a reforming section (reformer) without strongly pumping the raw fuel gas.
Another object of the present invention is to provide a solid oxide fuel cell device capable of reducing the projected projected area of the reforming section (reformer).

  In order to solve the above-described problems, the present invention provides a solid oxide fuel cell device that reforms a hydrocarbon-based raw fuel gas and generates power using the reformed fuel gas, and supplies the raw fuel gas A fuel supply device, a water supply device for supplying water for steam reforming the raw fuel gas supplied by the fuel supply device, an oxidant gas supply device for supplying an oxidant gas for power generation, A fuel cell stack for generating electric power by reacting an oxidant gas for power generation supplied by an oxidant gas supply device with a reformed fuel gas, and a fuel cell provided above the fuel cell stack Surrounds at least a part of the fuel cell stack and the combustion part that burns fuel gas that is not used for power generation in the stack, and receives heat from the fuel cell stack and the combustion part. A fuel gas supply channel disposed in the fuel gas supply channel, a fuel gas introduction unit that is provided at a lower portion of the fuel gas supply channel and that feeds the raw fuel gas supplied from the fuel supply device into the fuel gas supply channel, and a fuel gas In the supply channel, disposed above the fuel gas introduction unit, an evaporation unit for evaporating the water supplied from the water supply device, and provided in the fuel gas supply channel, introduced from the fuel gas introduction unit A reforming unit that reforms the raw fuel gas with water vapor generated in the evaporation unit, and the reforming unit is disposed above the evaporation unit so as to surround the upper part of the fuel cell stack. It is characterized by being.

  In the present invention configured as described above, the fuel supply device causes the raw fuel gas to flow into the fuel gas supply flow path disposed so as to surround at least a part of the fuel cell stack via the fuel gas introduction unit. Is done. On the other hand, water for steam reforming is supplied by the water supply device to an evaporation section disposed above the fuel gas introduction section in the fuel gas supply flow path, thereby generating steam. The supplied raw fuel gas and steam flow into a reforming section provided in the fuel gas supply flow path, and are steam reformed. The reformed fuel gas reacts with the oxidant gas for power generation supplied by the oxidant gas supply device in the fuel cell stack to generate electric power.

  According to the present invention configured as described above, the fuel gas supply channel is disposed so as to surround at least a part of the fuel cell stack and receive heat from the fuel cell stack and the combustion section. In addition, a reforming unit is provided in the fuel gas supply channel above the evaporation unit so as to surround the upper part of the fuel cell stack. For this reason, the temperature of the upper reforming section in the fuel gas supply channel is higher than that of the lower fuel gas introduction section and the evaporation section. As a result, an updraft is generated in the fuel gas supply channel, and this updraft causes the raw fuel gas introduced from the fuel gas introduction section to be mixed with the water vapor generated in the evaporation section without being strongly pumped. However, it can be easily fed into the upper reforming section. In addition, since the reforming unit is provided so as to surround the upper part of the fuel cell stack, the reforming catalyst can be widely distributed around the fuel cell stack, and the occupied projected area of the reforming unit is reduced. However, the reforming part can be sufficiently heated by the heat of the fuel cell stack and the combustion part.

  In the present invention, it is preferable that heat exchange with the fuel gas supply flow path is provided so as to surround at least a part of the fuel gas supply flow path, and the combustion gas burned in the combustion section is discharged. An exhaust gas discharge channel is provided, and the exhaust gas discharge channel guides the combustion gas from above the fuel cell stack to an exhaust gas outlet provided above the fuel gas introduction unit and below the evaporation unit.

  In the present invention configured as described above, the exhaust gas discharge passage is provided so as to surround at least a part of the fuel gas supply passage, and the combustion gas burned in the combustion section is discharged. Since the exhaust gas outlet of the exhaust gas discharge channel is provided below the evaporation unit, the evaporation unit can be sufficiently heated. Moreover, since the exhaust gas outlet is provided above the fuel gas introduction part, a temperature gradient can be created between the upper evaporation part and the fuel gas introduction part, and the exhaust gas outlet is introduced from the fuel gas introduction part. The raw fuel gas can be effectively conveyed upward by the rising airflow.

  In the present invention, it is preferable to further include an oxidant gas supply channel provided so as to exchange heat with the exhaust gas discharge channel so as to surround at least a part of the exhaust gas discharge channel. The gas supply channel guides the oxidant gas for power generation supplied from the oxidant gas supply device from the oxidant gas inlet provided above the evaporation unit to the upper side of the fuel cell stack.

  In this invention comprised in this way, the oxidizing gas supply flow path is provided so that heat exchange is possible between exhaust gas discharge flow paths. In addition, since the oxidant gas inlet of the oxidant gas supply channel is provided above the evaporation unit, the heat of the exhaust gas discharge channel is generated near the evaporation unit in the oxidant gas supply channel. Deprivation of the gas can be suppressed, and the evaporation section can be reliably heated by the heat of the exhaust gas.

  In the present invention, it is preferable that the fuel gas further includes a mixing unit provided in the fuel gas supply channel between the evaporation unit and the reforming unit, and introduces the raw fuel gas into the fuel gas supply channel. The introduction unit and the water introduction unit that introduces the water supplied from the water supply device into the evaporation unit are arranged close to each other and mixed in the mixing unit.

  In the present invention configured as described above, since the fuel gas introduction part for introducing the raw fuel gas and the water introduction part for introducing water are arranged close to each other, the raw fuel gas introduced from the fuel gas introduction part However, it is introduced into the mixing unit together with the water vapor generated in the vicinity of the water introduction unit, whereby the raw fuel gas and the water vapor can be effectively mixed.

  In the present invention, preferably, the evaporation unit is further configured by an inclined plate attached to the inner wall surface of the fuel gas supply flow path, and the water supplied from the water supply device is stored on the upper surface side of the inclined plate, The raw fuel gas supplied into the fuel gas supply channel from below the inclined plate flows upward while the channel is restricted by the inclined plate.

  In the present invention configured as described above, the raw fuel gas supplied into the fuel gas supply flow path from below the inclined plate flows upward while the flow path is restricted by the inclined plate. The water vapor generated on the upper surface side of the inclined plate is entrained in this flow, and the raw fuel gas and water vapor can be mixed effectively.

According to the solid oxide fuel cell device of the present invention, the raw fuel gas can be fed into the reforming section (reformer) without strongly feeding the raw fuel gas.
In addition, according to the solid oxide fuel cell device of the present invention, the occupied projected area of the reforming unit (reformer) can be reduced.

1 is an overall configuration diagram showing a solid oxide fuel cell apparatus (SOFC) according to an embodiment of the present invention. 1 is a perspective view showing an external appearance of a fuel cell storage container provided in a solid oxide fuel cell device according to an embodiment of the present invention. It is sectional drawing of the fuel cell storage container with which the solid oxide fuel cell apparatus by one Embodiment of this invention was equipped. FIG. 4 is a plan sectional view taken along line IV-IV in FIG. 3. It is a schematic sectional drawing which expands and shows the upper part of the fuel cell storage container with which the solid oxide fuel cell apparatus by one Embodiment of this invention was equipped. 1 is a block diagram showing a solid oxide fuel cell device according to an embodiment of the present invention. 3 is a time chart showing an operation at the time of starting the solid oxide fuel cell according to the embodiment of the present invention. FIG. 8 is a graph showing the temperature in the fuel gas supply channel and the temperature in the exhaust gas discharge channel at each position. (A) 10 minutes after startup, (b) 20 minutes after startup, (c) The temperature after starting 30 minutes is shown respectively. 1 is a perspective view showing a structure in a fuel gas supply channel formed between an inner cylindrical member and an outer cylindrical member of a solid oxide fuel cell according to an embodiment of the present invention. FIG. 3 is a schematic view of a fuel gas supply channel formed between an inner cylindrical member and an outer cylindrical member of a solid oxide fuel cell according to an embodiment of the present invention, developed along the outer circumferential direction of the inner cylindrical member. .

Next, a solid oxide fuel cell apparatus (SOFC) 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 fuel cell storage container 8 is disposed inside the housing 6 via a heat insulating material 7. A power generation chamber 10 is formed in the lower part of the fuel cell storage container 8, and a fuel cell stack 14 that performs a power generation reaction with air that is a fuel gas and an oxidant gas is stored in the power generation chamber 10. ing. The fuel cell stack 14 is composed of 100 fuel cell units 16 arranged concentrically.

  A combustion chamber 18 as a combustion portion is formed above the power generation chamber 10 in the fuel cell storage container 8 (above the fuel cell stack 14), and remains in the combustion chamber 18 without being used for a power generation reaction. The remaining fuel (off gas) and the remaining air are combusted to generate exhaust gas.

  Next, the auxiliary unit 4 stores a water from a water supply source 24 such as a tap water and uses a filter to obtain pure water, and a water for adjusting the flow rate of the water supplied from the pure water tank. A water flow rate adjustment unit 28 (such as a “water pump” driven by a motor) as a supply device is provided. The auxiliary unit 4 also has a fuel blower 38 (a “fuel pump” driven by a motor) that is a fuel supply device that adjusts the flow rate of a hydrocarbon-based raw fuel gas supplied from a fuel supply source 30 such as city gas. And a proportional valve 32 that distributes the raw fuel gas sent from the fuel blower 38.

  The raw fuel gas that has passed through the proportional valve 32 is introduced into the fuel cell storage container 8 through the desulfurizer 36 disposed in the fuel cell module 2, the heat exchanger 34, and the electromagnetic valve 35. . The desulfurizer 36 is formed in an annular shape so as to surround the periphery of the fuel cell storage container 8 and removes sulfur from the raw fuel gas. The heat exchanger 34 is provided to prevent the high temperature raw fuel gas whose temperature has risen in the desulfurizer 36 from flowing directly into the electromagnetic valve 35 and degrading the electromagnetic valve 35. The electromagnetic valve 35 is provided to stop the supply of the raw fuel gas into the fuel cell storage container 8.

  The accessory unit 4 includes an air flow rate adjustment unit 45 (such as an “air blower” driven by a motor) that is an oxidant gas supply device that adjusts the flow rate of air supplied from the air supply source 40.

Further, the auxiliary unit 4 is provided with a hot water production device 50 for recovering the heat of the exhaust gas from the fuel cell module 2. The hot water production apparatus 50 is supplied with tap water, 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).
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 2 to the outside.

Next, the fuel cell unit 16 will be described.
In the solid oxide fuel cell device 1 according to the embodiment of the present invention, a cylindrical horizontal stripe cell using a solid oxide is employed as the fuel cell unit 16.
The fuel cell unit 16 includes a cylindrical inner electrode layer (not shown), an electrolyte layer (not shown) provided around the inner electrode layer, and an outer electrode layer provided around the electrolyte layer. (Not shown). The inner electrode layer (not shown) is a fuel electrode through which fuel gas passes and becomes a (−) electrode, while the outer electrode layer (not shown) is an air electrode in contact with air, and (+) It is the pole. A fuel cell is formed by attaching various electrode terminals (not shown) to a cylindrical member composed of the inner electrode layer (not shown), the electrolyte layer (not shown), and the outer electrode layer (not shown). A cell unit 16 is configured. In actual use, fuel gas is caused to flow through a passage (not shown) inside a cylindrical inner electrode layer (not shown), and an oxidant gas for power generation around the outer electrode layer (not shown). As air is shed.

  The inner electrode layer (not shown) is, 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 doped with at least one selected from Ni and rare earth elements A mixture of ceria, and a mixture of Ni and a lanthanum garade doped with at least one selected from Sr, Mg, Co, Fe, and Cu.

  The electrolyte layer (not shown) is doped with, 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, and at least one selected from Sr and Mg Formed from at least one of lanthanum gallate.

  The outer electrode layer (not shown) 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 and Fe , Lanthanum cobaltite doped with at least one selected from Ni and Cu, silver, and the like.

  The fuel cell stack 14 is composed of 100 fuel cell units 16 arranged concentrically in the power generation chamber 10 of the fuel cell storage container 8. Various electrode terminals (not shown) and current collectors (not shown) attached to each fuel cell unit 16 are electrically connected to each other by a conductor (not shown), thereby providing a fuel cell stack. 14 is configured. A conductor (not shown) to which each fuel cell unit 16 is connected is connected to a bus bar 80 (FIG. 3) and drawn out from the fuel cell storage container 8.

Next, the internal structure of the fuel cell storage container built in the fuel cell module of the solid oxide fuel cell device (SOFC) according to the embodiment of the present invention will be described with reference to FIGS. FIG. 2 is a perspective view showing an appearance of the fuel cell storage container, and FIG. 3 is a cross-sectional view of the fuel cell storage container.
As shown in FIGS. 2 and 3, a fuel cell stack 14 in which a plurality of fuel cell units 16 are concentrically arranged is arranged in the sealed space in the fuel cell storage container 8 and surrounds the periphery thereof. Thus, the fuel gas supply channel 20, the exhaust gas discharge channel 21, and the oxidant gas supply channel 22 are formed concentrically in order.

  First, as shown in FIG. 2, the fuel cell storage container 8 is a substantially cylindrical sealed container, and the outer diameter of the lower part is thick. Further, an oxidant gas introduction pipe 56 that is an oxidant gas inlet for supplying power generation air and an exhaust gas discharge pipe 58 that discharges exhaust gas are connected to the lower side surface of the fuel cell storage container 8. . Further, a burner gas supply pipe 60 for supplying raw fuel gas to the built-in combustion burner is connected to the upper end surface of the fuel cell storage container 8, and the combustion burner is ignited from the upper end surface. The spark plug 62 for projecting out.

  As shown in FIG. 3, inside the fuel cell storage container 8, an inner cylindrical member 64, an outer cylindrical member 66, an inner cylindrical container 68, an outer side are arranged in order from the inner side so as to surround the periphery of the fuel cell stack 14. A cylindrical container 70 is arranged. The above-described fuel gas supply flow path 20, exhaust gas discharge flow path 21, and oxidant gas supply flow path 22 are flow paths configured between these cylindrical members and cylindrical containers, respectively, and between adjacent flow paths. Heat exchange takes place at. That is, the exhaust gas discharge passage 21 is disposed so as to surround the fuel gas supply passage 20, and the oxidant gas supply passage 22 is disposed so as to surround the exhaust gas discharge passage 21. The bottom surface of the fuel cell storage container 8 is sealed by a generally circular base member 72.

The inner cylindrical member 64 is a substantially cylindrical tube including an upper small-diameter portion, a lower large-diameter portion, and a tapered portion connecting them.
The outer cylindrical member 66 is a cylindrical tube disposed around the inner cylindrical member 64, and an inner cylindrical member is formed so that an annular flow path having a substantially constant width is formed between the outer cylindrical member 66 and the inner cylindrical member 64. 64 and a similar shape. An annular space between the outer peripheral surface of the inner cylindrical member 64 and the inner peripheral surface of the outer cylindrical member 66 functions as the fuel gas supply channel 20. For this reason, the fuel gas supply channel 20 receives heat from the surrounding fuel cell stack 14 and the combustion chamber 18. Further, the upper end portion of the inner cylindrical member 64 and the upper end portion of the outer cylindrical member 66 are joined, and the upper end of the fuel gas supply channel 20 is closed.

  The inner cylindrical container 68 is a cup-shaped member having a circular cross section disposed around the outer cylindrical member 66, and an annular flow path having a substantially constant width is formed between the inner cylindrical container 68 and the outer cylindrical member 66. The side surface is formed in a generally similar shape to the outer cylindrical member 66. An annular space between the outer peripheral surface of the outer cylindrical member 66 and the inner peripheral surface of the inner cylindrical container 68 functions as the exhaust gas discharge passage 21. The exhaust gas discharge passage 21 communicates with the space inside the inner cylindrical member 64 at the upper end portion of the outer cylindrical member 66. Further, an exhaust gas discharge pipe 58 that is an exhaust gas outlet is connected to the lower side surface of the inner cylindrical container 68, and the exhaust gas discharge passage 21 is communicated with the exhaust gas discharge pipe 58.

  The outer cylindrical container 70 is a cup-shaped member having a circular cross section disposed around the inner cylindrical container 68, and an annular channel having a substantially constant width is formed between the outer cylindrical container 70 and the inner cylindrical container 68. The side surface is formed in a substantially similar shape to the inner cylindrical container 68. An annular space between the outer peripheral surface of the inner cylindrical container 68 and the inner peripheral surface of the outer cylindrical container 70 functions as the oxidant gas supply channel 22. Further, an oxidant gas introduction pipe 56 is connected to the lower side surface of the outer cylindrical container 70, and the oxidant gas supply flow path 22 communicates with the oxidant gas introduction pipe 56.

  The base member 72 is a substantially disk-shaped member, and is configured to form a sealed fuel cell storage container 8 by being fixed to a flange provided at the lower end of the inner cylindrical container 68 via a packing. Yes. The lower ends of the inner cylindrical member 64 and the outer cylindrical member 66 also extend to the base member 72.

  An oxidant gas injection pipe 74 having a circular cross section for injecting air for power generation is attached so as to hang down from the ceiling surface of the inner cylindrical container 68. The oxidant gas injection pipe 74 extends in the vertical direction on the central axis of the inner cylindrical container 68, and each fuel cell unit 16 is disposed on a concentric circle around it. By attaching the upper end of the oxidant gas injection pipe 74 to the ceiling surface of the inner cylindrical container 68, the oxidant gas supply flow path 22 and the oxidant gas formed between the inner cylindrical container 68 and the outer cylindrical container 70 are formed. An injection pipe 74 is communicated. On the other hand, the lower end surface of the oxidizing gas injection pipe 74 is closed, and a plurality of injection ports 74a are provided on the side surface of the lower end portion. The air supplied from the oxidant gas supply channel 22 flows into the oxidant gas injection pipe 74 and radiates from the plurality of injection holes 74a provided on the side surface of the lower end toward the surrounding fuel cell units 16. Is injected into.

  A fuel gas dispersion chamber 76 having a donut-shaped cross section is provided on the upper surface of the base member 72. The fuel gas dispersion chamber 76 is an airtight chamber provided on the base member 72 so as to be concentric with the base member 72, and each fuel cell unit 16 is erected on the upper surface thereof. Each fuel cell unit 16 attached to the upper surface of the fuel gas dispersion chamber 76 has an inner fuel electrode communicating with the inside of the fuel gas dispersion chamber 76.

  On the other hand, a reformed gas transfer pipe 78 is provided so as to connect the inner cylindrical member 64 and the upper surface of the fuel gas dispersion chamber 76. The reformed gas transfer pipe 78 is a pipe that extends from the inner upper part of the inner cylindrical member 64 to the upper surface of the fuel gas dispersion chamber 76 in a substantially vertical direction. The upper end of the reformed gas transfer pipe 78 communicates with the fuel gas supply channel 20 between the inner cylindrical member 64 and the outer cylindrical member 66, and the lower end penetrates the upper surface of the fuel gas dispersion chamber 76 to disperse the fuel gas. It extends to the inside of the chamber 76. As a result, the fuel gas that has risen in the fuel gas supply flow path 20 passes downward through the reformed gas transfer pipe 78 and flows into the fuel gas dispersion chamber 76. The fuel gas flowing into the fuel gas dispersion chamber 76 is distributed to the fuel electrode of each fuel cell unit 16.

  Further, a bus bar 80 is attached to the center of the base member 72 so as to penetrate the base member 72. The bus bar 80 is an elongated metal plate conductor for taking out the electric power generated by the fuel cell stack 14 to the outside of the fuel cell storage container 8, and is attached to the base member 72 via an insulator. The bus bar 80 is electrically connected to a current collector attached to each fuel cell unit 16 to be described later inside the fuel cell housing container 8. The bus bar 80 is connected to the inverter 54 (FIG. 1) outside the fuel cell storage container 8.

  A cylindrical cell stack heat insulating material 82 is attached to the upper surface of the base member 72 so as to surround the fuel gas dispersion chamber 76. The heat insulating material 82 for heat retention of the cell stack is a cylindrical heat insulating material configured to surround the entire fuel gas dispersion chamber 76 and the periphery of about 2/3 of the lower part of the fuel cell stack 14. Further, the upper part of the upper part of the heat insulating material 82 for cell stack heat insulation is tapered so that the thickness of the heat insulating material gradually decreases toward the upper end. With this configuration, the heat insulation between the fuel cell stack 14 and the surrounding inner cylindrical member 64 gradually decreases toward the upper end of the cell stack heat insulating material 82.

Next, the structure of the combustion burner will be described with reference to FIGS.
4 is a plan sectional view taken along line IV-IV in FIG. FIG. 5 is an enlarged schematic cross-sectional view showing the upper part of the fuel cell storage container.

  As shown in FIGS. 3 to 5, the combustion burner 84 is a generally donut-shaped burner disposed at the upper end in the fuel cell storage container 8, and an oxidant gas injection pipe 74 is provided on the central axis thereof. It is penetrated. A plurality of gas injection ports 84a are provided on the outer peripheral portion of the combustion burner 84, and flames are formed radially from the combustion burner 84 in a generally horizontal direction, as shown in FIG. An ejector 84 b is provided on the upper surface of the combustion burner 84. The ejector 84b is formed as an inlet for introducing fuel gas into the combustion burner 84, and the fuel gas is injected from the tip of the burner gas supply pipe 60 toward the inlet. The fuel gas injected from the tip of the burner gas supply pipe 60 is introduced into the combustion burner 84 while drawing in ambient air and exhaust gas. The fuel gas and air flowing into the combustion burner 84 are mixed inside and injected from each gas injection port 84a.

  Further, the spark plug 62 (FIG. 3) is disposed so that the tip thereof is positioned in the vicinity of the gas injection port 84a. By generating a spark at the tip of the ignition plug 62, the spark plug 62 (FIG. 3) The injected fuel gas and air mixture is ignited. The flame of the combustion burner 84 heats the upper end portion of the inner cylindrical member 64 facing the gas injection port 84a. The upper end portion of the inner cylindrical member 64 heated by the combustion burner 84 functions as a heating portion 64a (FIG. 5).

Next, a configuration for reforming the raw fuel gas supplied from the fuel supply source 30 will be described with reference to FIG.
First, an evaporating portion 86 for evaporating water for steam reforming is provided in the lower portion of the fuel gas supply flow path 20 configured by a space between the inner cylindrical member 64 and the outer cylindrical member 66. . The evaporation unit 86 includes a ring-shaped inclined plate 86 a attached to the lower inner periphery of the outer cylindrical member 66 and a water supply pipe 88. The evaporator 86 is disposed below the oxidant gas introduction pipe 56 for introducing power generation air and above the exhaust gas discharge pipe 58 that discharges exhaust gas. The inclined plate 86 a is a metal thin plate formed in a ring shape, and its outer peripheral edge is attached to the inner wall surface of the outer cylindrical member 66. On the other hand, the inner peripheral edge of the inclined plate 86 a is positioned above the outer peripheral edge, and a gap is provided between the inner peripheral edge of the inclined plate 86 a and the outer wall surface of the inner cylindrical member 64.

  The water supply pipe 88 is a pipe extending through the base member 72 in the vertical direction, and the water for steam reforming supplied from the water flow rate adjustment unit 28 is supplied to the evaporation unit 86 through the water supply pipe 88. The The upper end of the water supply pipe 88 passes through the inclined plate 86a and extends to the upper surface side of the inclined plate 86a, and the water supplied to the upper surface side of the inclined plate 86a is the upper surface of the inclined plate 86a and the inner wall surface of the outer cylindrical member 66. Stay between. The water supplied to the upper surface side of the inclined plate 86a is evaporated there to generate water vapor. Thus, the upper end part of the water supply pipe 88 functions as the water introduction part 88a.

  A fuel gas introduction part for introducing the raw fuel gas into the fuel gas supply channel 20 is provided below the evaporation part 86. The raw fuel gas sent from the fuel blower 38 is introduced into the fuel gas supply channel 20 via the fuel gas supply pipe 90. The fuel gas supply pipe 90 is a pipe that extends through the base member 72 in the vertical direction, and is disposed in the vicinity of the water supply pipe 88. Further, the upper end of the fuel gas supply pipe 90 is positioned below the inclined plate 86a. Therefore, the upper end portion of the fuel gas supply pipe 90 functions as the fuel gas introduction portion 90a. The raw fuel gas sent from the fuel blower 38 is introduced to the lower side of the inclined plate 86a and rises to the upper side of the inclined plate 86a while the flow path is restricted by the inclination of the inclined plate 86a. The raw fuel gas that has risen to the upper side of the inclined plate 86 a rises together with the water vapor generated in the evaporation section 86.

  A mixing unit 92 is provided above the evaporation unit 86 in the fuel gas supply channel 20. The mixing unit 92 is constituted by three spiral blades 92 a attached to the outer wall surface of the inner cylindrical member 64. Each spiral blade 92a is formed of a C-shaped thin plate that makes a round around the inner cylindrical member 64, and this plate is attached to the outer wall surface of the inner cylindrical member 64 so as to draw a spiral. Further, since the outer peripheral edge of each spiral blade 92a extends to the vicinity of the inner wall surface of the outer cylindrical member 66, a flow path that draws a spiral is formed in the fuel gas supply flow path 20 by each spiral blade 92a. The By passing through the spiral flow path, the raw fuel gas introduced from the fuel gas introduction unit 90a and the water vapor generated by the evaporation unit 86 are sufficiently mixed.

  Furthermore, a reforming unit 94 is provided above the mixing unit 92 in the fuel gas supply channel 20 and below the heating unit 64a (FIG. 5) at the upper end of the fuel gas supply channel 20. The reforming part 94 is arranged so as to surround the upper part of the fuel cell stack 14 and the periphery of the combustion chamber 18 thereabove. The reforming unit 94 includes six catalyst holding spiral plates 94a attached to the outer wall surface of the inner cylindrical member 64, and two catalysts attached to the outer wall surface of the inner cylindrical member 64 at the upper and lower portions of the catalyst holding spiral plate 94a. The holding ventilation plate 94b and the reforming catalyst 96 held by these are constituted. Each catalyst holding spiral plate 94a is composed of a C-shaped thin plate that makes a round around the inner cylindrical member 64, and is attached to the outer wall surface of the inner cylindrical member 64 so as to draw a spiral. Further, since the outer peripheral edge of each catalyst holding spiral plate 94a extends to the vicinity of the inner wall surface of the outer cylindrical member 66, the catalyst holding spiral plate 94a causes a substantially spiral flow in the fuel gas supply channel 20. A path is formed. Each catalyst holding vent plate 94b is provided with a large number of pores to ensure air permeability. The size of the pores is such that air permeability is secured so that the reforming catalyst 64 is kept from passing and the raw fuel gas and water vapor can flow into and out of the reforming section 94. The reforming catalyst 96 is filled in the catalyst holding spiral plates 94a and the catalyst holding vent plates 94b.

Thus, when the raw fuel gas and water vapor mixed in the mixing unit 92 come into contact with the reforming catalyst 96 filled in the reforming unit 94, the water vapor represented by the formula (1) is formed in the reforming unit 94. The reforming reaction SR proceeds.
C _m H _n + xH ₂ O → aCO ₂ + bCO + cH ₂ (1)

  The fuel gas reformed in the reforming unit 94 flows downward through the reformed gas transfer pipe 78, flows into the fuel gas dispersion chamber 76, and is supplied to each fuel cell unit 16. Although the steam reforming reaction SR is an endothermic reaction, the heat required for the reaction includes heat conducted from the heating unit 64a (FIG. 5) heated by the combustion burner 84, combustion heat generated in the combustion chamber 18, and It is supplied by the generated heat generated in the fuel cell stack 14.

Next, the sensors and the like provided in the solid oxide fuel cell apparatus (SOFC) according to the present embodiment will be described with reference to FIG. FIG. 6 is a block diagram showing a solid oxide fuel cell apparatus 1 (SOFC) according to an embodiment of the present invention.
As shown in FIG. 6, the solid oxide fuel cell device 1 includes a control unit 110, and the control unit 110 includes operation buttons such as “ON” and “OFF” for operation by the user. The operation device 112, a display device 114 for displaying various data such as a power generation output value (wattage), and a notification device 116 for issuing a warning (warning) in an abnormal state are connected. The notification device 116 may be connected to a remote management center and notify the management center of an abnormal state. In addition, the control unit 110 incorporates a microcomputer, a memory, and a program (not shown) for operating them, thereby controlling each device connected to the control unit 110.

Next, signals from various sensors described below are input to the control unit 110.
First, the combustible gas detection sensor 120 is for detecting a gas leak, and is attached to the fuel cell module 2 and the auxiliary unit 4.
The CO detection sensor 122 detects whether or not CO in the exhaust gas originally discharged to the outside through the exhaust gas passage 80 or the like leaks to an external housing (not shown) that covers the fuel cell module 2 and the auxiliary unit 4. Is to do.
The hot water storage state detection sensor 124 is for detecting the temperature and amount of hot water in a water heater (not shown).

The power state detection sensor 126 is for detecting the current and voltage of the inverter 54 and the distribution board (not shown).
The power generation air flow rate detection sensor 128 is for detecting the flow rate of power generation air supplied to the power generation chamber 10.
The reforming air flow sensor 130 is for detecting the flow rate of the reforming air supplied to the reformer 20.
The fuel flow sensor 132 is for detecting the flow rate of the fuel gas supplied to the reformer 20.

The water flow rate sensor 134 is for detecting the flow rate of pure water supplied to the reformer 20.
The water level sensor 136 is for detecting the water level of the pure water tank 26.
The pressure sensor 138 is for detecting the pressure on the upstream side outside the reforming unit 94.
The exhaust temperature sensor 140 is for detecting the temperature of the exhaust gas flowing into the hot water production apparatus 50.

The power generation chamber temperature sensor 142 detects the temperature near the fuel cell stack 14 and estimates the temperature of the fuel cell stack 14.
The combustion chamber temperature sensor 144 is for detecting the temperature of the combustion chamber 18.
The exhaust gas chamber temperature sensor 146 is for detecting the temperature of the exhaust gas flowing through the exhaust gas discharge passage 21.
The reformer temperature sensor 148 is for detecting the temperature of the reforming unit 94, and calculates the temperature of the reforming unit 94 from the inlet temperature and the outlet temperature of the reforming unit 94.
The outside air temperature sensor 150 is for detecting the temperature of the outside air when the solid oxide fuel cell device 1 (SOFC) is disposed outdoors. Further, a sensor for measuring the humidity or the like of the outside air may be provided.

  Signals from these sensors are sent to the control unit 110, and the control unit 110 sends control signals to the water flow rate adjustment unit 28, the fuel blower 38, and the air flow rate adjustment unit 45 based on the data obtained by these signals. Each flow rate in these units is controlled.

  Next, the operation at the time of starting of the solid oxide fuel cell apparatus 1 (SOFC) according to the present embodiment will be described with reference to FIG. FIG. 7 is a time chart showing the operation at the start-up of the solid oxide fuel cell (SOFC) according to one embodiment of the present invention, and the temperature of the power generation chamber 10 reflecting the temperature of the fuel cell stack 14, and The transition of the temperature of the reforming part 94 is shown. Further, in FIG. 7, together with these temperatures, the supply flow rate of power generation air, the supply flow rate of fuel gas to the combustion burner 84, the supply flow rate of fuel gas to the reforming unit 94, and the evaporation unit 86 are shown. Although the supply flow rate of water is shown, these represent the tendency of increase / decrease of each supply flow rate, and do not represent the specific supply amount.

  When the solid oxide fuel cell device 1 is activated, an activation process is performed to raise the temperature of the fuel cell stack 14 in the fuel cell module 2 to a temperature at which power can be generated. In this starting process, power is not taken out from the fuel cell module 2 to the inverter 54. Therefore, the fuel cell module 2 does not generate power in the startup process.

  First, at time t <b> 1 in FIG. 7, the air flow rate adjustment unit 45 is activated by the control unit 110 and supply of air to the fuel cell module 2 is started. The supplied air flows from the oxidant gas introduction pipe 56 into the oxidant gas supply channel 22, flows upward in the oxidant gas supply channel 22, and then flows into the oxidant gas injection pipe 74. To do. The air flowing into the oxidant gas injection pipe 74 descends, and the fuel cell units 16 arranged so as to surround the oxidant gas injection pipe 74 from the injection port 74a at the lower end of the oxidant gas injection pipe 74. Sprayed to the bottom. The air blown to the lower part of each fuel cell unit 16 (lower part of the fuel cell stack 14) rises in the power generation chamber 10 and flows into the combustion chamber 18, and the inside of the combustion burner 84 and the inner cylindrical member 64. The ceiling space of the inner cylindrical container 68 is reached through the annular space between the wall surfaces. The air that has reached the ceiling surface of the inner cylindrical container 68 flows in the radial direction and flows into the exhaust gas discharge passage 21 formed between the inner cylindrical container 68 and the outer cylindrical member 66. The air flowing into the exhaust gas discharge passage 21 descends and is discharged out of the fuel cell module 2 from the exhaust gas discharge pipe 58. Thereby, the gas staying in the power generation chamber 10 and the combustion chamber 18 of the fuel cell module 2 is also discharged out of the fuel cell module 2.

  Next, at time t1, the control unit 110 activates the fuel blower 38. When the fuel blower 38 is activated, the raw fuel gas supplied from the fuel supply source 30 is sent to the proportional valve 32. At time t <b> 1, the proportional valve 32 is set in a state where all the supplied raw fuel gas is sent to the combustion burner 84. Therefore, the raw fuel gas flowing out from the proportional valve 32 flows into the burner gas supply pipe 60. The raw fuel gas that has flowed into the burner gas supply pipe 60 is injected from its lower end toward the ejector 84 b of the combustion burner 84. The raw fuel gas injected into the ejector 84b flows into the combustion burner 84 together with the air while enclosing the surrounding air. The raw fuel gas that has flowed into the combustion burner 84 is injected radially in the horizontal direction from the gas injection ports 84a.

  Further, at time t2, the control unit 110 sends a signal to the spark plug 62 to ignite the raw fuel gas injected from the gas injection port 84a. As a result, the combustion operation for increasing the temperature in the fuel cell module 2 by the combustion heat of the combustion burner 84 is started. The flame of the combustion burner 84 heats the heating portion 64 a that is the upper end portion of the inner cylindrical member 64 that is disposed so as to face the outer peripheral surface of the combustion burner 84. When the heating unit 64a is heated, the temperature of the entire inner cylindrical member 64 increases due to heat conduction, and the temperature of the outer cylindrical member 66 joined to the inner cylindrical member 64 also increases. As a result, the reforming catalyst 96 in the reforming section 94 disposed between the inner cylindrical member 64 and the outer cylindrical member 66 is also heated and the temperature rises.

  Further, the temperatures in the power generation chamber 10 and the combustion chamber 18 surrounded by the inner cylindrical member 64 also increase. Further, the high-temperature combustion gas generated by the combustion burner 84 flows into the exhaust gas discharge passage 21 through the space between the combustion burner 84 and the heating unit 64a. That is, the exhaust gas generated by the combustion is discharged through the exhaust gas discharge passage 21 between the outer cylindrical member 66 and the inner cylindrical container 68. At this time, the reforming portion 94 provided on the inner side of the outer cylindrical member 66 is heated from the periphery, and the air flowing in the oxidant gas supply channel 22 provided on the outer side of the inner cylindrical container 68 is heated. Thereby, the temperature of the air flowing into the power generation chamber 10 through the oxidant gas injection pipe 74 also increases, and the temperature in the power generation chamber 10 also increases. By these actions, the temperature in the power generation chamber 10 and the temperature of the reforming unit 94 rise after time t2.

  When the temperature of the reforming unit 94 rises sufficiently, the control unit 110 starts supplying fuel and water vapor to the reforming unit 94 at time t3. As a result, the SR1 step for generating the steam reforming reaction SR in the reforming section 94 is started while the inside of the fuel cell module 2 is heated with the combustion heat of the combustion burner 84. Specifically, the setting of the proportional valve 32 is changed by the control unit 110, and the inflowing raw fuel gas is supplied to the combustion burner 84 and the reforming unit 94. In addition, the control unit 110 activates the water flow rate adjustment unit 28 and starts supplying water to the evaporation unit 86.

  By changing the setting of the proportional valve 32, the raw fuel gas flowing into the proportional valve 32 is supplied to the desulfurizer 36 in addition to the combustion burner 84. In the raw fuel gas flowing into the desulfurizer 36, sulfur content is removed there. At time t3, the temperature of the catalyst (not shown) in the desulfurizer 36 disposed so as to surround the fuel cell storage container 8 is also raised to a temperature at which desulfurization can be performed, and the sulfur sufficiently Minutes can be removed. The raw fuel gas flowing out from the desulfurizer 36 is lowered in temperature by the heat exchanger 34 and flows into the fuel cell storage container 8 through the electromagnetic valve 35. In addition, deterioration of the following solenoid valve 35 is prevented by lowering the temperature of the raw fuel gas flowing out from the desulfurizer 36 by the heat exchanger 34.

  The raw fuel gas that has passed through the electromagnetic valve 35 flows into the fuel gas supply channel 20 from the fuel gas introduction part 90 a at the tip of the fuel gas supply pipe 90. The inside of the fuel gas supply flow path 20 is in a state where the upper temperature is high because the upper heating portion 64a is heated. Further, since the exhaust gas discharge pipe 58 of the exhaust gas discharge passage 21 is provided above the fuel gas introduction part 90a, the portion above the fuel gas introduction part 90a is heated by the heat of the exhaust gas. The temperature above the fuel gas introduction part 90a increases. For this reason, since an updraft exists in the fuel gas supply flow path 20, the raw fuel gas flowing in from the fuel gas introduction part 90a rises with the updraft. At this time, since the flow path of the raw fuel gas is narrowed by the inclined plate 86a attached above the fuel gas introduction part 90a so that the upper part is narrowed, the flow rate of the raw fuel gas is increased here.

  On the other hand, the reforming water sent out by the water flow rate adjusting unit 28 flows out from the water introduction portion 88a at the tip of the water supply pipe 88 and flows into the upper surface of the inclined plate 86a. Here, the outside of the outer cylindrical member 66 to which the inclined plate 86a is attached is the exhaust gas discharge passage 21, and the high-temperature exhaust gas that has heated the reforming unit 94 flows down to the periphery of the inclined plate 86a. ing. Due to the flow of the high-temperature exhaust gas, the temperature of the inclined plate 86a constituting the evaporator 86 and the outer cylindrical member 66 in the vicinity thereof also rises, so that the water flowing into the evaporator 86 from the water introduction part 88a is evaporated. Water vapor is generated. The temperature of the exhaust gas flowing down in the exhaust gas discharge passage 21 is lowered by heating the reforming section 94 above, but the evaporation section 86 needs to be heated to a higher temperature as the reforming section 94 is heated. Therefore, the exhaust gas after heating the reforming section 94 can be sufficiently heated. The evaporator 86 also receives heat from the fuel cell stack 14 side, but since the cell stack heat insulation 82 is disposed between the fuel cell stack 14 and the evaporator 86, the evaporator 86 evaporates. The part 86 is heated mainly by heat from the exhaust gas discharge passage 21.

  Further, since the exhaust gas exhaust pipe 58 that exhausts exhaust gas is disposed below the evaporation unit 86, the exhaust gas is exhausted from the exhaust gas exhaust pipe 58 after heating the evaporation unit 86. Thereby, the evaporator 86 is sufficiently heated by the heat of the exhaust gas flowing in the exhaust gas discharge passage 21. The evaporator 86 is disposed below the oxidant gas introduction pipe 56 for introducing air for power generation. For this reason, the portion of the exhaust gas discharge passage 21 surrounding the evaporation portion 86 is not easily deprived of heat by the air flowing in the oxidant gas supply passage 22, and the evaporation portion 86 is reliably heated by the heat of the exhaust gas. Is done.

  Here, the fuel gas introduction part 90a and the water introduction part 88a are arranged in the vicinity. For this reason, the raw fuel gas that flows in from the fuel gas introduction portion 90a and rises between the inner peripheral edge of the inclined plate 86a and the outer wall surface of the inner cylindrical member 64 is introduced from the water introduction portion 88a, and is formed on the upper surface of the inclined plate 86a. The inside of the fuel gas supply channel 20 rises together with the rising airflow while being immediately mixed with the water vapor evaporated in the vicinity of the water introduction portion 88a. The raw fuel gas and the water vapor reach the mixing unit 92 disposed above the evaporation unit 86, where the circumference of the inner cylindrical member 64 is along the spiral flow path formed by each spiral blade 92a. Ascend around. The raw fuel gas and the water vapor are sufficiently mixed by rising while swirling the spiral flow path.

  The raw fuel gas and water vapor sufficiently mixed in the mixing section 92 further rise and reach the reforming section 94 disposed above the mixing section 92. In the reforming unit 94, the raw fuel gas and the water vapor spirally flow along the catalyst holding spiral plate 94a arranged so as to form a spiral, and come into contact with the reforming catalyst 96 here. As a result, the steam reforming reaction SR shown in the above formula (1) occurs, and the raw fuel gas is reformed into a fuel gas rich in hydrogen.

  The fuel gas reformed in the reforming section 94 flows downward through the reformed gas transfer pipe 78 and flows into the fuel gas dispersion chamber 76. The fuel gas flowing into the fuel gas dispersion chamber 76 flows into the fuel electrode inside each fuel cell unit 16 disposed on the upper surface of the fuel gas dispersion chamber 76. The fuel gas that has flowed into the fuel electrode rises in each fuel cell unit 16 and flows out from the upper end of each fuel cell unit 16. At time t3, since the temperature in the power generation chamber 10 is sufficiently increased, the fuel gas flowing out from the upper end of each fuel cell unit 16 is burned, and a flame is formed at the upper end of each fuel cell unit 16. Is done. The reforming portion 94 disposed so as to surround the combustion chamber 18 is also heated by the combustion heat of the fuel gas in the combustion chamber 18 above each fuel cell unit 16.

  As described above, the steam reforming reaction SR generated in the reforming section 94 is an endothermic reaction, but the heat required for this reaction is heating to the heating section 64 a by the combustion burner 84 and combustion in the combustion chamber 18. It is covered by heat and heat of the exhaust gas flowing from the combustion chamber 18 through the exhaust gas discharge passage 21 around the reforming portion 94.

  When the temperature in the fuel cell module 2 rises to a predetermined temperature, the control unit 110 starts the SR2 process at time t4. In the SR2 step, the setting of the proportional valve 32 is changed by the control unit 110, and the amount of fuel gas supplied to the combustion burner 84 is decreased, while the amount of fuel gas supplied to the reforming unit 94 is increased. Further, the flow rate of water supplied to the evaporator 86 by the water flow rate adjusting unit 28 is also increased. Thereby, the heating by the combustion burner 84 decreases, and the heating by the combustion heat of the fuel gas flowing out from the upper end of each fuel cell unit 16 increases.

  When the temperature in the fuel cell module 2 further increases and reaches a predetermined temperature, the control unit 110 starts the SR3 process at time t5. In the SR3 step, the setting of the proportional valve 32 is changed by the control unit 110, the supply of fuel gas to the combustion burner 84 is stopped, and the fuel gas supply amount to the reforming unit 94 is increased. Further, the flow rate of water supplied to the evaporator 86 by the water flow rate adjusting unit 28 is also increased. As a result, heating by the combustion burner 84 is stopped, and heating is performed exclusively by the combustion heat of the fuel gas flowing out from the upper end of each fuel cell unit 16.

  Further, when the temperature of the fuel cell stack 14 reaches a temperature at which power generation is possible, the control unit 110 ends the startup process and starts the power generation process at time t6. Specifically, the fuel cell module 2 is connected to the inverter 54 by the control unit 110, and current is extracted to the inverter 54 via the bus bar 80. As a result, a power generation reaction occurs between the fuel gas flowing on the fuel electrode side (inner side) of each fuel cell unit 16 and the air flowing on the air electrode side (outer side) to generate electric power. In the power generation process, the fuel gas supply flow rate, the water supply flow rate, and the power generation air flow rate are determined according to the required power generation amount. In the solid oxide fuel cell device 1 of the present embodiment, the fuel gas supply flow rate, the water supply flow rate, and the power generation air flow rate in the SR3 step are larger than the respective flow rates necessary for generating the maximum rated power. Is set. Therefore, when shifting from the SR3 process to the power generation process, the fuel gas supply flow rate, the water supply flow rate, and the air flow rate are reduced.

  In the power generation process, power generation heat is generated in each fuel cell unit 16. Therefore, the inside of the fuel cell module 2 is also heated by the generated heat of each fuel cell unit 16. In particular, the reforming portion 94 disposed so as to surround the upper part of the fuel cell stack 14 is heated by the generated heat. For this reason, even during the power generation process, the temperature of the upper part of the fuel gas supply channel 20 is high and the temperature of the lower part is low. Sent.

  Further, since the temperature inside the power generation chamber 10 is heated by the combustion heat in the combustion chamber 18, the temperature tends to be higher at the upper portion and lower at the lower portion. However, temperature unevenness is likely to occur between the upper part and the lower part.

  However, in the solid oxide fuel cell device 1 of the present embodiment, the lower part of the fuel cell stack 14 is surrounded by the cell stack heat insulating material 82, so that it is generated at the lower part of each fuel cell unit 16. The generated heat hardly transfers to the surrounding inner cylindrical member 64 (fuel gas supply flow path 20), and the lower part of each fuel cell unit 16 is kept warm. On the other hand, the upper part of each fuel cell unit 16 where the temperature is likely to rise is directly opposed to the reforming part 94 in which an endothermic reaction is occurring, so that the generated heat is easily taken away. Thereby, the temperature nonuniformity between the upper part and the lower part in each fuel cell unit 16 is suppressed.

  Further, the heat insulating material 82 for keeping the cell stack surrounding the fuel cell stack 14 is formed so as to become gradually thinner toward the upper end. Thereby, in each fuel cell unit 16, the occurrence of temperature unevenness due to a sudden change in heat insulation between the portion surrounded by the cell stack heat insulating material 82 and the portion not surrounded is suppressed. Further, in the solid oxide fuel cell device 1 of the present embodiment, the inner cylindrical member 64 is formed such that the lower inner diameter is large and the upper inner diameter is small. For this reason, the distance from the fuel cell stack 14 to the surrounding inner cylindrical member 64 is separated at the lower part of the fuel cell stack 14, and the distance to the inner cylindrical member 64 is closer at the upper part. The distance from the battery cell stack to the inner cylindrical member 64 is increased. As a result, the fuel gas supply channel 20 is less likely to receive heat from the fuel cell stack 14 from the lower part of the fuel cell stack 14 than from the upper part of the fuel cell stack 14. In other words, in the lower part of the fuel cell stack 14, the generated heat is less likely to be taken, and temperature unevenness between the upper and lower parts of each fuel cell unit 16 is suppressed.

  Further, in the solid oxide fuel cell apparatus 1 of the present embodiment, the power generation air is injected radially from the oxidant gas injection pipe 74 disposed in the center of the fuel cell stack 14, and the power generation chamber 10. After ascending the inside, it flows into the annular exhaust gas discharge passage 21 from the upper end edge of the inner cylindrical member 64. For this reason, the flow of air in the power generation chamber 10 and the combustion chamber 18 is almost completely axisymmetric, and air is uniformly distributed around each fuel cell unit 16 constituting the fuel cell stack 14. Flowing. Thereby, the temperature difference between each fuel cell unit 16 is suppressed, and an equal electromotive force can be generated in each fuel cell unit 16.

  Next, with reference to FIG. 8, the temperature distribution in the fuel cell storage container 8 in the starting process will be described. FIGS. 8A to 8C are graphs showing the temperature in the fuel gas supply passage 20 and the temperature in the exhaust gas discharge passage 21 at the positions A, B, C, and D shown in FIG. The temperature in the fuel gas supply passage 20 is indicated by a solid line, and the temperature in the exhaust gas discharge passage 21 is indicated by a broken line. FIG. 8 (a) shows the temperature distribution after 10 minutes of startup, (b) shows 20 minutes later, and (c) shows 30 minutes later. As shown in FIG. 3, the position A is near the upper end of the fuel cell storage container 8, the position A in the fuel gas supply channel 20 is near the heating unit 64 a, and the position in the exhaust gas discharge channel 21. A is near the entrance of the exhaust gas discharge passage 21. The position B corresponds to a portion where the reforming portion 94 is formed in the fuel gas supply channel 20. The position C corresponds to a portion between the mixing unit 92 and the reforming unit 94. The position D corresponds to a portion where the evaporation portion 86 is formed in the fuel gas supply channel 20.

  First, as shown in FIG. 8 (a), after 10 minutes from the start, the temperature at the position A in the vicinity of the heating unit 64a heated by the combustion burner 84 rises, but at the lower positions B to D. The temperature has not risen much. Further, the temperature in the exhaust gas discharge passage 21 indicated by a broken line is higher than the temperature in the fuel gas supply passage 20 indicated by a solid line.

  Next, as shown in FIG. 8B, after 20 minutes from the start, the heat at the position A in the vicinity of the heating unit 64a is conducted to the lower positions B and C, the temperature is rising, and the reforming is performed. The temperature of the portion 94 is starting to rise. On the other hand, the temperature at the position D has not risen so much yet. Further, as apparent from FIG. 8B, the temperature in the exhaust gas discharge passage 21 is higher than the temperature in the fuel gas supply passage 20, and the exhaust gas flowing in the exhaust gas discharge passage 21 causes the fuel gas to flow. The fuel gas, water, and reforming catalyst 96 in the supply flow path 20 are heated. Further, in FIG. 8B, the temperature at the position D in the fuel gas supply channel 20 has risen to about 100 ° C., so that water vapor can be generated in the evaporator 86.

  Furthermore, as shown in FIG. 8C, it can be seen that the temperature at the position B approaches the position A after 30 minutes from the start, and the reforming catalyst 96 is sufficiently heated. Further, as apparent from FIGS. 8B and 8C, the temperature in the fuel gas supply flow path 20 becomes higher as it goes upward, so that the fuel gas is not much added by the blower or the like due to the rising airflow generated thereby. Even if it is not pressurized, it rises in the fuel gas supply channel 20 and is sent to the reforming section 94. Further, the water vapor generated in the evaporating unit 86 is also sent to the reforming unit 94 while being mixed with the fuel gas by the rising airflow. In this way, a large temperature gradient is generated in the fuel gas supply flow path 20, while temperature unevenness between the upper and lower portions of the fuel cell stack 14 surrounded by the fuel gas supply flow path 20 is , Suppressed as described above.

Next, referring to FIG. 3, FIG. 9 and FIG. 10, in the fuel gas supply flow path formed between the inner cylindrical member and the outer cylindrical member of the solid oxide fuel cell according to the embodiment of the present invention. The structure will be described in more detail.
FIG. 9 is a perspective view showing a structure in the fuel gas supply channel formed between the outer wall surface of the inner cylindrical member and the inner wall surface of the outer cylindrical member of the solid oxide fuel cell according to the embodiment of the present invention. FIG. 10 shows the fuel gas supply flow path formed between the inner cylindrical member and the outer cylindrical member of the solid oxide fuel cell according to the embodiment of the present invention along the outer circumferential direction of the inner cylindrical member. FIG.
Here, FIG. 10 is a view in which the outer wall surface 152 of the inner cylindrical member 64 shown in FIG. 9 is cut along a predetermined cut line L1 extending in the vertical direction and developed in the outer peripheral direction of the inner cylindrical member 64. Further, FIG. 10 shows an angle (that is, the inner cylindrical member 64 of the inner cylindrical member 64) developed from the cut line L1 counterclockwise around the central axis C1 of the inner cylindrical member 64 shown in FIG. The angle (corresponding to the circumferential angle of the outer wall surface 152) is θ (degrees), and the outer wall surface 152 of the inner cylindrical member 64 is shown in a circumferential direction, that is, the angle θ is expanded from 0 degrees to 360 degrees. .

  As shown in FIGS. 3, 9, and 10, in the fuel gas supply flow path 20 formed between the outer wall surface 152 of the inner cylindrical member 64 and the inner wall surface 154 of the outer cylindrical member 66, A swirl passage portion 156 is provided between the reforming portion 94 and the swirl passage portion 156 is introduced into the fuel gas supply passage 20 from the fuel gas introduction portion 90a of the fuel gas supply pipe 90. The raw fuel gas F thus raised and the water vapor S introduced from the water introduction part 88 a of the water supply pipe 88 and generated by the evaporation part 86 are swirled along the circumferential direction of the fuel gas supply flow path 20. In addition, a flow (mixed air flow) M for uniformly supplying the mixed raw fuel gas and water vapor over the entire circumference of the reforming portion 94 can be formed.

  More specifically, the swirl flow path section 156 includes the raw fuel gas F introduced and raised from the fuel gas introduction section 90a into the fuel gas supply flow path 20, and the water vapor S generated and raised by the evaporation section 86. Is provided with a spiral channel portion 158 that forms a spiral channel that swirls along the circumferential direction of the fuel gas supply channel 20. The spiral flow path portion 158 substantially corresponds to the mixing portion 92 described above, and includes three spiral blades 92 a made of a C-shaped thin plate that makes a round around the inner cylindrical member 64.

Further, as shown in FIGS. 9 and 10, these three spiral blades 92 a are composed of the first spiral blade 160, the second spiral blade 162, and the third spiral blade 164, and the lower edge of the first spiral blade 160 is formed. The position P1 is closest to the line L1 among the three spiral blades 160, 162, and 164, and the position Q1 of the upper edge of the first spiral blade 160 is the position P1 of the lower edge of the first spiral blade 160. It is located almost directly above.
Further, the position P2 of the lower edge of the second spiral blade 162 has an angle θ in the circumferential direction of the outer wall surface 152 of the inner cylindrical member 64 with respect to the position P1 of the lower edge of the first spiral blade 160 about the central axis C. The position is shifted by 120 degrees, and the position Q2 of the upper edge of the second spiral blade 162 is located almost directly above the position P2 of the lower edge of the second spiral blade 162.
Similarly, the position P3 of the lower edge of the third spiral blade 164 is an angle θ in the circumferential direction of the outer wall surface 152 of the inner cylindrical member 64 about the center axis C with respect to the position P1 of the lower edge of the first spiral blade 160. Is shifted by 240 degrees, and the angle θ is further shifted by 120 degrees in the circumferential direction of the outer wall surface 152 of the inner cylindrical member 64 around the central axis C with respect to the position P2 of the lower edge of the second spiral blade 162. The position Q3 of the upper edge of the third spiral blade 164 is located almost directly above the position P3 of the lower edge of the third spiral blade 164.

  The spiral channel portion 158 of the swirl channel portion 156 is formed in a spiral shape by these three spiral blades 160, 162, 164, the outer wall surface 152 of the inner cylindrical member 64, and the inner wall surface 154 of the outer cylindrical member 66. The first spiral channel 166, the second spiral channel 168, and the third spiral channel 170 are provided. Here, the first spiral channel 166 is formed by the first spiral blade 160, the second spiral blade 162, the outer wall surface 152 of the inner cylindrical member 64, and the inner wall surface 154 of the outer cylindrical member 66. Similarly, the second spiral channel 168 is formed by the second spiral blade 162, the third spiral blade 164, the outer wall surface 152 of the inner cylindrical member 64, and the inner wall surface 154 of the outer cylindrical member 66. The flow path 170 is formed by the first spiral blade 160, the third spiral blade 164, the outer wall surface 152 of the inner cylindrical member 64, and the inner wall surface 154 of the outer cylindrical member 66.

In the present embodiment, the outer peripheral edges of the spiral blades 160, 162, 164 extend to the vicinity of the inner wall surface 154 of the outer cylindrical member 66, and a slight gap is formed between the outer peripheral member 66 and the inner wall surface 154. Therefore, although the cross-sections of the spiral channels 166, 168, and 170 are not completely closed, the cross-sections of the spiral channels 166, 168, and 170 are spiral. You may set to the completely closed flow-path cross section in which the clearance gap between the outer periphery of the blade | wing 160,162,164 and the inner wall surface 154 of the outer side cylindrical member 66 is not formed.
Further, the spiral channels 166, 168, and 170 may be set to two or four or more spiral channels.

Further, each of the three spiral channels 166, 168, 170 of the spiral channel portion 158 is almost directly above the inlets 166a, 168a, 170a located at the lower end and the positions of the respective inlets 166a, 168a, 170a. Positioned outlets 166b, 168b, 170b are provided. The length of the flow path from each inlet 166a, 168a, 170a of each spiral flow path 166, 168, 170 to each outlet 166b, 168b, 170b along each spiral flow path 166, 168, 170 is determined by the inner cylindrical member 64. It is set substantially equal to the length of the outer periphery of the outer wall surface 152.
Further, as shown in FIGS. 9 and 10, the position of the inlet 168a of the second spiral flow path 168 is the position of the inner cylindrical member 64 around the central axis C with respect to the position of the inlet 166a of the first spiral flow path 166. The angle θ is shifted by 120 degrees in the circumferential direction of the outer wall surface 152, and the position of the inlet 170 a of the third spiral channel 170 is the central axis C with respect to the position of the inlet 168 a of the second spiral channel 168. Is the position where the angle θ is shifted by 120 degrees in the circumferential direction of the outer wall surface 152 of the inner cylindrical member 64.
Similarly, the position of the outlet 168b of the second spiral channel 168 is an angle θ in the circumferential direction of the outer wall surface 152 of the inner cylindrical member 64 about the central axis C with respect to the position of the outlet 166b of the first spiral channel 166. And the position of the outlet 170b of the third spiral channel 170 is outside the inner cylindrical member 64 around the central axis C with respect to the position of the outlet 168b of the second spiral channel 168. The angle θ is shifted by 120 degrees in the circumferential direction of the wall surface 152.

Next, the swirl flow path section 156 is formed between the evaporation section 86 and the spiral flow path section 158, and is introduced into the fuel gas supply flow path 20 from the fuel gas introduction section 90a and rises to the raw fuel gas F. A single lower dispersion chamber 172 that disperses the water vapor S generated and raised by the evaporation section 86 in the spiral flow path section 158 is provided.
In addition, the swirl flow path portion 156 is formed between the spiral flow path portion 158 and the reforming portion 94, and the mixing ratio of the raw fuel gas and water vapor mixed in the spiral flow path portion 158 is made uniform. A single upper dispersion chamber 174 is provided for dispersion over the entire circumference of the mass portion 94.
Here, the volume V1 of the lower dispersion chamber 172 is set to be smaller than the volume V2 of the upper dispersion chamber 174 so that the spiral flow path section 158 and the evaporation section 86 can be brought close to each other. Thereby, the heat in each spiral flow path 166, 168, 170 of the spiral passage portion 158 can be transmitted to the lower evaporation portion 86 using the spiral blades 160, 162, 164 as a heat transfer medium. Together with the updraft generated by the transmitted heat, the raw fuel gas and water vapor can be reliably guided to the spiral passage portion 158.

  Further, the upper dispersion chamber 174 is not provided with spiral blades such as the spiral blades 160, 162, and 164 of the spiral flow path portion 158, but in the upper dispersion chamber 174, each spiral flow path portion 158 is provided. When the mixed air flow M of the raw fuel gas and the water vapor mixed by swirling in the spiral flow paths 166, 168, and 170 flows into the upper dispersion chamber 174 from the outlets 166b, 168b, and 170b, the mixing is performed. The air flow M can be dispersed in the upper dispersion chamber 174 having a larger volume than the spiral flow paths 166, 168, and 170, and can be further raised spirally. As a result, even if the mixing ratio of the mixed airflow M is different at the time of flowing out from each of the outlets 166b, 168b, 170b of the spiral channels 166, 168, 170 in the upper dispersion chamber 174, The airflow M is further spirally raised in the upper dispersion chamber 174 and mixed, and the mixed airflow M having a uniform mixing ratio passes through the inlets 176 formed on the bottom surface of the reforming section 94 and is then reformed. 94 is supplied.

  According to the solid oxide fuel cell device 1 of the embodiment of the present invention, the fuel gas supply channel 20 surrounds the fuel cell stack 14 and is arranged to receive heat from the fuel cell stack 14 and the combustion unit 18. (FIG. 3). In addition, a reforming unit 94 is provided in the fuel gas supply channel 20 above the evaporation unit 86 so as to surround the upper part of the fuel cell stack 14. For this reason, the temperature of the reforming unit 94 above the fuel gas supply channel 20 is higher than that of the lower fuel gas introduction unit 90a and the evaporation unit 86 (FIG. 8). As a result, an updraft is generated in the fuel gas supply flow path 20, and the water vapor generated in the evaporation unit 86 without strongly pumping the raw fuel gas introduced from the fuel gas introduction unit 90 a by this updraft. It can be easily fed into the upper reforming section 94 while being mixed with the mixture. In addition, since the reforming unit 94 is provided so as to surround the upper part of the fuel cell stack 14, the reforming catalyst can be widely distributed around the fuel cell stack 14. The reforming unit 94 can be sufficiently heated by the heat of the fuel cell stack 14 and the combustion unit 18 while suppressing the area to be small.

  Further, according to the solid oxide fuel cell device 1 of the present embodiment, the exhaust gas discharge passage 21 is provided so as to surround the fuel gas supply passage 20 (FIG. 3), and the combustion gas burned in the combustion section 18 Is discharged. Since the exhaust gas discharge pipe 58 of the exhaust gas discharge channel 21 is provided below the evaporation unit 86, the evaporation unit 86 can be sufficiently heated. Further, since the exhaust gas discharge pipe 58 is provided above the fuel gas introduction part 90a, a temperature gradient can be created between the upper evaporation part 86 and the fuel gas introduction part 90a, and the fuel gas introduction part The raw fuel gas introduced from 90a can be effectively conveyed upward by the rising airflow.

Furthermore, according to the solid oxide fuel cell device 1 of the present embodiment, the oxidant gas supply channel 22 is provided so as to be able to exchange heat with the exhaust gas discharge channel 21. Further, since the oxidant gas inlet of the oxidant gas supply flow path 22 is provided above the evaporation part (FIG. 3), the heat of the exhaust gas discharge flow path 21 near the evaporation part 86 causes the oxidant to flow. Deprivation of the air in the gas supply flow path 22 can be suppressed, and the evaporator 86 can be reliably heated by the heat of the exhaust gas.
Further, according to the solid oxide fuel cell device 1 of the present embodiment, the fuel gas introduction part 90a for introducing the raw fuel gas and the water introduction part 88a for introducing water are arranged close to each other (FIG. 3). Therefore, the raw fuel gas introduced from the fuel gas introduction unit 90a is introduced into the mixing unit together with the water vapor generated in the vicinity of the water introduction unit 88a, thereby effectively mixing the raw fuel gas and the water vapor. it can.

  Furthermore, according to the solid oxide fuel cell device 1 of the present embodiment, the raw fuel gas supplied from the lower side of the inclined plate 86a into the fuel gas supply channel 20 is narrowed by the inclined plate 86a. Since it flows upward (FIG. 3), the flow rate of the raw fuel gas is increased, and the water vapor generated on the upper surface side of the inclined plate 86a is entrained in this flow, so that the raw fuel gas and the water vapor can be mixed effectively. .

  As mentioned above, although preferable embodiment of this invention was described, a various change can be added to embodiment mentioned above. In particular, in the above-described embodiment, the fuel gas supply flow path is provided so as to surround the entire circumference of the fuel cell stack. However, the fuel gas supply flow path may be only surrounded by a part of the fuel cell stack. Good. Similarly, the exhaust gas discharge flow path surrounds the entire circumference of the fuel gas supply flow path, and the oxidant gas supply flow path surrounds the entire circumference of the exhaust gas discharge flow path, but these also only need to partially surround them. .

DESCRIPTION OF SYMBOLS 1 Solid oxide fuel cell apparatus 2 Fuel cell module 4 Auxiliary machine unit 7 Heat insulating material 8 Fuel cell storage container 10 Power generation chamber 14 Fuel cell stack 16 Fuel cell unit 18 Combustion chamber (combustion part)
20 Fuel gas supply channel 21 Exhaust gas discharge channel 22 Oxidant gas supply channel 24 Water supply source 26 Pure water tank 28 Water flow rate adjustment unit (water supply device)
30 Fuel Supply Source 32 Proportional Valve 34 Heat Exchanger 35 Solenoid Valve 36 Desulfurizer 38 Fuel Blower (Fuel Supply Device)
40 Air supply source 45 Air flow rate adjustment unit (oxidant gas supply device)
50 Hot water production equipment 54 Inverter 56 Oxidant gas introduction pipe (oxidant gas inlet)
58 Exhaust gas exhaust pipe (exhaust gas outlet)
60 Gas supply pipe for burner 62 Spark plug 64 Inner cylindrical member 64a Heating unit 66 Outer cylindrical member 68 Inner cylindrical container 70 Outer cylindrical container 72 Base member 74 Oxidant gas injection pipe 74a Injection port 76 Fuel gas dispersion chamber 78 Reforming gas Transfer pipe 80 Bus bar 82 Cell stack heat insulating material 84 Combustion burner 84a Gas injection port 84b Ejector 86 Evaporating part 86a Inclined plate 88 Water supply pipe 88a Water introduction part 90 Fuel gas supply pipe 90a Fuel gas introduction part 92 Mixing part 92a Spiral blade 94 reforming section 94a catalyst holding plate 96 reforming catalyst 110 control section (control means)
112 Operation device 114 Display device 116 Alarm device 126 Power state detection sensor (output voltage detection means)
132 Fuel flow sensor (fuel supply amount detection means)
138 Pressure sensor (reformer pressure sensor)
140 Exhaust temperature sensor 142 Power generation chamber temperature sensor (temperature detection means)
148 Reformer temperature sensor (temperature detection means)
150 Outside air temperature sensor 152 Outer wall surface 154 of the inner cylindrical member Inner wall surface 156 of the outer cylindrical member Rotating flow channel portion 158 Spiral flow channel portion 160 First spiral blade 162 Second spiral blade 164 Third spiral blade 166 First spiral flow channel 166a First spiral channel inlet 166b First spiral channel outlet 168 Second spiral channel 168a Second spiral channel inlet 168b Second spiral channel outlet 170 Third spiral channel 170a Third spiral channel Inlet 170b Third spiral channel outlet 172 Lower dispersion chamber (second dispersion chamber)
174 Upper dispersion chamber (first dispersion chamber)
176 Inlet of reforming section

Claims (5)

A solid oxide fuel cell device that reforms a hydrocarbon-based raw fuel gas and generates electric power using the reformed fuel gas,
A fuel supply device for supplying raw fuel gas;
A water supply device for supplying water for steam reforming the raw fuel gas supplied by the fuel supply device;
An oxidant gas supply device for supplying an oxidant gas for power generation;
A fuel cell stack that generates electric power by reacting the oxidant gas for power generation supplied by the oxidant gas supply device with the reformed fuel gas; and
A combustion unit that is provided above the fuel cell stack and burns fuel gas remaining in the fuel cell stack without being used for power generation;
A fuel gas supply channel that surrounds at least a portion of the fuel cell stack and is arranged to receive heat from the fuel cell stack and the combustion section;
A fuel gas introduction section provided at a lower portion of the fuel gas supply flow path for allowing the raw fuel gas supplied from the fuel supply device to flow into the fuel gas supply flow path;
An evaporating unit disposed in the fuel gas supply flow path above the fuel gas introducing unit and evaporating water supplied from the water supply device;
A reforming unit that is provided in the fuel gas supply channel and reforms the raw fuel gas introduced from the fuel gas introduction unit with water vapor generated in the evaporation unit, and
The solid oxide fuel cell device, wherein the reforming unit is disposed above the evaporation unit so as to surround an upper portion of the fuel cell stack.   Further, an exhaust gas discharge passage that is provided so as to be able to exchange heat with the fuel gas supply passage so as to surround at least a part of the fuel gas supply passage and discharges the combustion gas burned in the combustion section. The exhaust gas discharge passage guides the combustion gas from above the fuel cell stack to an exhaust gas outlet provided above the fuel gas introduction part and below the evaporation part. 2. The solid oxide fuel cell device according to 1.   Furthermore, it has an oxidant gas supply flow path provided so as to be able to exchange heat with the exhaust gas discharge flow path so as to surround at least a part of the exhaust gas discharge flow path. The oxidant gas for power generation supplied from the oxidant gas supply device is led from the oxidant gas inlet provided above the evaporation unit to the upper side of the fuel cell stack. Solid oxide fuel cell device.   Furthermore, the fuel gas introduction part which has a mixing part provided in the fuel gas supply flow path between the evaporation part and the reforming part, and introduces the raw fuel gas into the fuel gas supply flow path 4. The solid oxide fuel cell device according to claim 3, wherein a water introduction part that introduces water supplied from the water supply apparatus into the evaporation part is disposed adjacently and mixed in the mixing part.   The evaporating section is configured by an inclined plate attached to the inner wall surface of the fuel gas supply flow path, and water supplied from the water supply device is stored on the upper surface side of the inclined plate, and more than the inclined plate. 4. The solid oxide fuel cell device according to claim 3, wherein the raw fuel gas supplied from below into the fuel gas supply channel flows upward while the channel is narrowed by the inclined plate.

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