JP6635856B2 - Thermal insulation structure of fuel cell module - Google Patents

Description

  The present invention relates to a heat insulating structure for a fuel cell module.

  2. Description of the Related Art In a fuel cell, a heat insulating structure is provided in order to maintain the fuel cell module in a high temperature region where the performance of the fuel cell module is suitably exhibited. As an example of such a heat insulating structure, Patent Literature 1 discloses a fuel cell module in which a reactor having a reforming unit that generates a reformed gas containing hydrogen is housed in an outer container. A hydrogen generator is described in which at least a part between the two is filled with a heat insulating material. Patent Literature 2 describes a heat insulating structure in which a heat insulating layer made of three block heat insulating materials having different heat insulating performances is provided inside a casing.

JP 2008-16264 A JP 2013-82603 A

However, in the technology described in Patent Literature 1, since a single heat insulating material is merely provided in the outer container, a structure having higher heat insulating performance is desired.
Further, in the technique described in Patent Literature 2, three block heat insulating materials are superposed and provided in the casing, so that the casing becomes large.

  Then, this invention was made in view of the said point, and makes it a subject to provide the heat insulation structure of the fuel cell module which can make compactness and suitable heat insulation performance compatible.

In order to solve the above-mentioned problem, a heat insulation structure of a fuel cell module of the present invention is a heat insulation structure of a fuel cell module having a fuel cell stack and a peripheral device unit, and is provided so as to surround the fuel cell module. An outer heat insulating layer made of a block heat insulating material which is provided outside the inner heat insulating layer and has a housing shape in which the fuel cell module and the inner heat insulating layer are accommodated. And an intermediate heat insulating layer formed by air is provided between the inner heat insulating layer and the outer heat insulating layer, and the intermediate heat insulating layer is supplied to a cathode of the fuel cell stack. A gas passage through which an oxidizing gas flows is provided, and the peripheral device unit includes an exhaust gas combustor for burning exhaust gas discharged from the fuel cell stack. The gas burner of the exhaust gas combustor is characterized by extending in the gas flow path.

According to such a configuration, a suitable heat insulating performance can be realized by a three-layer heat insulating structure, and since an intermediate heat insulating layer made of air is provided in the middle, both compactness and a suitable heat insulating performance can be achieved. .
Further, according to this configuration, the oxidizing gas exchanges heat to recover the waste heat discharged from the inner heat insulating layer to the outside, so that the oxidizing gas can be heated using the waste heat.

  The heat insulating structure of the fuel cell module includes an inner housing in which the fuel cell module is housed, and an outer housing in which the inner housing is housed, and the inner heat insulating layer is filled in the inner housing. The intermediate heat insulating layer is formed between the inner housing and the outer housing, and the outer heat insulating layer having a housing shape has the outer heat insulating layer. A configuration in which a housing is accommodated may be employed.

  According to such a configuration, the inner heat-insulating layer can be easily formed by filling the inner heat-insulating material with the granular heat-insulating material, and the intermediate heat-insulating layer by air can be easily formed between the inner housing and the outer housing. It is possible.

  ADVANTAGE OF THE INVENTION According to this invention, in a fuel cell module, both compactness and suitable heat insulation performance can be achieved.

FIG. 1 is a system diagram illustrating a basic configuration of a fuel cell system. FIG. 2 is a schematic diagram that abstractly illustrates a heat recovery casing according to the embodiment and a fuel cell module housed in the heat recovery casing. FIG. 2 is a perspective view of the heat recovery casing according to the embodiment as viewed from the front and from the lower left side. FIG. 2 is a perspective view of the heat recovery casing according to the embodiment as viewed from the rear and upper right side.

  First, the basic configuration of the fuel cell system 1 and the fuel cell module 10 will be described, and then, the fuel cell heat recovery casing according to the embodiment of the present invention (hereinafter, referred to as “radiation recovery casing”). 40 will be described.

  As shown in FIG. 1, the fuel cell system 1 includes a fuel cell module (SOFC (Solid Oxide Fuel Cell) module) 10 and is used for various purposes such as stationary use and in-vehicle use. Used.

The fuel cell module 10 is a device that generates power by an electrochemical reaction between a fuel gas (a gas in which methane and carbon monoxide are mixed with hydrogen gas) and an oxidant gas (air).
The fuel cell system 1 further includes a raw fuel supply device (including a fuel gas pump) 2, an oxidizing gas supply device (including an air pump) 3, a water supply device (including a water pump) 4, a desulfurizer 5, and a control device 6. Is provided.

The raw fuel supply device 2 supplies a fuel gas (for example, city gas) to the fuel cell module 10. The oxidizing gas supply device 3 supplies an oxidizing gas to the fuel cell module 10. The water supply device 4 supplies water to the fuel cell module 10. The desulfurizer 5 removes a sulfur compound contained in the raw fuel. The control device 6 controls the power generation amount of the fuel cell module 10.
In addition, flow rate control valves 7 and 8 are provided on the fuel gas supply flow path and the oxidizing gas supply flow path, and the supply amount is appropriately adjusted.

  The fuel cell module 10 includes a solid oxide fuel cell stack 12 in which a plurality of solid oxide flat plate fuel cells are stacked in the vertical direction. In the present embodiment, the plurality of fuel cells in the fuel cell module 10 are stacked in the vertical direction, but the stacking direction is not particularly limited, and the fuel cells may be stacked in the horizontal direction.

  Although not specifically shown, the fuel cell includes, for example, a flat electrolyte-electrode assembly (MEA) in which a cathode electrode and an anode electrode are provided on both surfaces of an electrolyte composed of an oxide ion conductor such as stabilized zirconia. Prepare.

  A plate-shaped cathode-side separator and a plate-shaped anode-side separator are disposed on both sides of the electrolyte-electrode assembly. An oxidizing gas passage for supplying an oxidizing gas to the cathode electrode is formed in the cathode-side separator. A fuel gas flow path for supplying a fuel gas to the anode electrode is formed in the anode-side separator.

The operating temperature of the fuel cell of this embodiment is as high as 700 ° C.
At the anode electrode of the fuel cell, methane in the fuel gas is reformed to obtain hydrogen and CO, and the hydrogen and CO are supplied to the anode side of the electrolyte.

In the fuel cell stack 12, an oxidizing gas inlet communication hole 12a integrally communicating with an inlet side of each oxidizing gas flow path, and an oxidizing gas exhaust gas communication hole 12c integrally communicating with an outlet side of the oxidizing gas flow path. Is provided.
The fuel cell stack 12 is further provided with a fuel gas inlet communication hole 12b integrally communicating with the inlet side of each fuel gas flow path, and a fuel exhaust gas outlet communication hole 12d integrally communicating with the outlet side of the fuel gas flow path. .

The fuel cell module 10 reforms the fuel gas supplied to the fuel cell stack 12 and raises the temperature of the fuel gas / oxidizing gas, so that the evaporator 21, the reformer 22, the first heat exchanger 23, An exhaust gas combustor 24, a starting combustor 25, and a second heat exchanger (not shown) are provided.
The evaporator 21, the reformer 22, the first heat exchanger 23, the exhaust gas combustor 24, the starting combustor 25, and the second heat exchanger are integrated (unitized) (see FIG. 2). .
In addition, the evaporator 21, the reformer 22, the first heat exchanger 23, the exhaust gas combustor 24, the starting combustor 25, and the second heat exchanger are collectively referred to as a BOP (Balance Of Plant) 20. The BOP 20 is a peripheral device unit of the fuel cell stack 12, and constitutes the fuel cell module 10 together with the fuel cell stack 12. Further, the fuel cell module 10 is housed in a heat recovery casing 30.

The evaporator 21 evaporates water. Further, the steam generated in the evaporator 21 is mixed with a raw fuel mainly composed of hydrocarbons and supplied to the reformer 22 as a mixed gas.
The reformer 22 reforms a mixed gas of a raw fuel (eg, city gas) mainly composed of hydrocarbons and steam to generate a fuel gas to be supplied to the fuel cell stack 12.
The fuel gas is supplied to each fuel gas flow channel of the fuel cell stack 12 via a fuel gas supply pipe 13b connected to the fuel gas inlet communication hole 12b.

The exhaust gas combustor 24 burns the fuel exhaust gas and the oxidant exhaust gas discharged from the fuel cell stack 12 to generate a combustion gas, and supplies the combustion gas to the first heat exchanger 23.
The fuel exhaust gas and the oxidant exhaust gas are supplied to the exhaust gas combustor 24 via a fuel exhaust gas discharge pipe 13d connected to the fuel exhaust gas outlet communication hole 12d and an oxidant exhaust gas discharge pipe 13c connected to the oxidant exhaust gas outlet communication hole 12c. Supplied to

The first heat exchanger 23 raises the temperature of the oxidizing gas by heat exchange with the combustion gas.
The heated oxidizing gas is supplied to each oxidizing gas flow path of the fuel cell stack 12 via an oxidizing gas supply pipe 13a connected to the oxidizing gas inlet communication hole 12a.

The starting combustor 25 burns the raw fuel and the oxidizing gas to generate combustion gas, and supplies the combustion gas to the second heat exchanger.
The second heat exchanger raises the temperature of the oxidizing gas by heat exchange with the combustion gas. Then, the heated oxidizing gas is supplied to each oxidizing gas flow path of the fuel cell stack 12 via the first heat exchanger 23 and the oxidizing gas supply pipe 13a, and warms up the fuel cell stack 12. .

As shown in FIG. 2, the fuel cell system 1 further includes a heat recovery casing 30 that houses the fuel cell module 10 therein, and a coupling bracket 40 that connects the heat recovery collection casing 30 and the fuel cell module 10. And
The fuel cell module 10 is arranged so that the BOP 20 is located below the fuel cell stack 12 in the heat recovery casing 30.

The heat recovery casing 30 is a casing formed of a metal having heat resistance to heat radiation of the fuel cell, for example, stainless steel.
The heat recovery casing 30 includes a bottom wall portion 31, a front wall portion 32, a rear wall portion 33, a left wall portion 34, a right wall portion 35, and an upper wall portion 36 (see FIGS. 3 and 4).
Therefore, when the fuel cell stack 12 operates, the bottom wall portion 31, the front wall portion 32, the rear wall portion 33, the left wall portion 34, the right wall portion 35, and the upper wall portion 36 are connected to the fuel cell module 10 (particularly, the fuel cell module 10). The temperature is raised by the heat radiation energy of the stack 12).

  The heat recovery casing 30 includes a gas flow path 50 provided in each wall, a gas inlet 52 provided on the lower surface of the bottom wall 31, and a gas outlet provided on the upper surface of the bottom wall 31. 54.

The gas flow path 50 is a flow path (space) through which the oxidizing gas supplied from the oxidizing gas supply device 3 to the fuel cell module 10 flows.
The gas inlet 52 is an opening through which the oxidizing gas flows into the gas passage 50. The gas inflow port 52 of the present embodiment has an inflow port 51 formed therein, and the gas outflow port 54 is an opening through which the oxidizing gas flowing through the gas flow path 50 flows out. A connecting pipe 53 is connected to the gas outlet 54 of the present embodiment, and an oxidizing gas is supplied to the BOP 20 via the connecting pipe 53.

As described above, according to the heat recovery casing 30, the oxidizing gas flowing through the gas flow path 50 absorbs thermal energy from the wall and is heated (preheated). Therefore, the preheated oxidizing gas is supplied to the BOP 20.
The specific structure of the heat recovery casing 30 will be described later.

  Further, the coupling bracket 40 is for fixing the fuel cell module 10 to the heat recovery casing 30 in a suspended state.

The connection bracket 40 includes a first connection bracket 41 provided on an inner surface of the left wall portion 34 and an inner surface of the right wall portion 35, a second connection bracket 42 connected to a lower portion of the fuel cell stack 12, and a connection portion above the BOP 20. And a third coupling bracket 43 to be used.
Further, the second coupling bracket 42 and the third coupling bracket 43 are coupled to the first coupling bracket 41 by a fastener (not shown), and the fuel cell module 10 is fixed in the heat recovery casing 30.

In addition, the coupling bracket 40 of the present embodiment is provided at an intermediate portion in the height direction.
Therefore, a first gap S1 is formed between the top of the fuel cell stack 12 and the upper wall 36.
Similarly, a second gap S2 is formed between the bottom of the BOP 20 and the bottom wall 31.
As described above, when the fuel cell stack 12 operates, the fuel cell stack 12 thermally expands upward with reference to the supported second coupling bracket 42 (see the arrow A1 in FIG. 2), and the first gap S1 becomes narrow.
On the other hand, the BOP 20 thermally expands downward with reference to the third coupling bracket 43 (see the arrow A2 in FIG. 2), and the second gap S2 becomes narrow.

  Here, with respect to a method of fixing the fuel cell module 10 to the heat recovery casing 30, for example, it is conceivable to fix the upper end and the lower end of the fuel cell module 10 to the heat recovery casing 30. However, according to the fixing method, when the fuel cell stack 12 operates, the temperature of the fuel cell module 10 is higher than that of the heat recovery casing 30. In other words, since the fuel cell module 10 has a larger thermal expansion than the heat recovery casing 30, distortion may occur. Therefore, according to the fixing method described above, the difference in the amount of thermal expansion can be absorbed, and the occurrence of distortion can be avoided.

  In addition, the gas burner 24a, which is a component of the exhaust gas combustor 24, is fixed to the right wall 35 via a flange 24b. Therefore, the heat energy of the gas burner 24a is transferred to the right wall 35, and the temperature of the right wall 35 is higher than that of the other walls. As a result, when the oxidizing gas flows through the gas flow path 50 of the right wall 35, the temperature tends to rise more easily than the gas flow path 50 of the other wall.

  Further, the gas burner 24 a is located on the upper side of the BOP 20 and is close to the third coupling bracket 43. For this reason, even if the BOP 20 thermally expands downward with respect to the third coupling bracket 43, the gas burner 24a is unlikely to be distorted.

Next, a specific structure of the heat recovery casing 30 will be described.
As shown in FIGS. 3 and 4, the heat recovery casing 30 includes a bottomed rectangular tubular main body 60 that opens upward and a rectangular lid 80 that covers the opening of the main body 60. And a partition section 90 provided in the main body section 60 and the lid section 80 to set the gas flow path 50.

The main body part 60 is a part that forms the bottom wall part 31, the front wall part 32, the rear wall part 33, the left wall part 34, and the right wall part 35.
The main body section 60 has a double structure including a bottomed rectangular tubular inner wall section 61 and a bottomed rectangular tubular outer wall section 62 surrounding the outside of the inner wall section 61 in a state separated from the inner wall section 61. I have.
For this reason, the bottom wall portion 31, the front wall portion 32, the rear wall portion 33, the left wall portion 34, and the right wall portion 35 of the present embodiment each have a gas space into which an oxidizing gas can flow. .

In addition, in order to make the gas space of each wall part visually recognizable, the outer wall part 62 is notched or shown by the two-dot chain line in FIGS.
In addition, the gas space in the bottom wall portion 31 is referred to as a bottom wall gas space 71 for convenience of description.
The gas space in the front wall portion 32 is referred to as a front wall gas space 72.
The gas space in the rear wall portion 33 is referred to as a rear wall gas space 73.
The gas space in the left wall portion 34 is referred to as a left wall gas space 74.
The gas space in the right wall portion 35 is referred to as a right wall gas space 75.

  As shown in FIG. 4, a gas inlet 52 and an inflow port 51 that penetrate vertically are formed in an outer wall 62 that forms the bottom wall 31. The gas inlet 52 is located at the center in the front-rear direction and to the left.

  A gas outlet 54 penetrating in the up-down direction is formed in the inner wall portion 61 constituting the bottom wall portion 31. The gas outlet 54 is formed at the center in the left-right direction and at the front.

As shown in FIG. 3, the lid 80 is a part that forms the upper wall 36.
The lid 80 includes a flat bottom plate 81 for closing the opening of the main body 60, an annular side wall 82 extending along the peripheral edge of the bottom plate 81, and an upper plate (not shown) for closing the upper side of the side wall 82. Thereby, an upper wall gas space 76 is formed in the upper wall portion 36.
In addition, the lid 80 blocks the upper part of the gas space of the main body 60 (the upper part between the inner wall 61 and the outer wall 62).

  The partition section 90 is for partitioning a gas space in the main body section 60 and the lid section 80 and setting a flow path (gas flow path 50) through which gas flows, and includes a first partition member 91 to a seventh partition member 97. Is provided.

  As shown in FIGS. 3 and 4, the first partition member 91 and the second partition member 92 are arranged in the bottom wall gas space 71 and extend in the front-rear direction while being separated from each other left and right.

  The first partition member 91 is located between the gas inlet 52 and the gas outlet 54. For this reason, the bottom wall gas space 71 is divided into an inflow gas space 71A continuous with the gas inlet 52 and an outflow gas space 71B continuous with the gas outlet 54.

  The second partition member 92 is located on the right side of the gas outlet 54. For this reason, the outlet gas space 71B and the right wall gas space 75 are separated by the second partition member 92 and are not continuous (see FIG. 3).

  The third partition member 93 is disposed in the bottom wall gas space 71 and extends horizontally in front of the first partition member 91 and the second partition member 92, and extends upward from the left end of the horizontal portion 93a to the left. And a vertical portion 93b disposed in the wall gas space 74.

The horizontal portion 93a extends leftward from the front end 92a of the second partition member 92.
The front end 91a of the first partition member 91 and the front end 92a of the second partition member 92 are in contact with the horizontal portion 93a.
Therefore, the outlet gas space 71B and the front wall gas space 72 are partitioned by the horizontal portion 93a and are not continuous. Similarly, the inflow gas space 71A and the front wall gas space 72 are separated by a horizontal portion 93a and are not continuous.

  The upper end of the vertical portion 93b extends to the vicinity of the lid 80 that closes the upper part of the left wall gas space 74, but does not abut the lid 80. Therefore, a first communication port 101 that connects the front wall gas space 72 and the left wall gas space 74 is formed above the vertical portion 93b.

  The fourth partition member 94 is an L-shaped member including a horizontal portion 94a extending leftward from a rear end portion 91b of the first partition member 91, and a vertical portion 94b extending upward from the left end portion of the horizontal portion 94a. is there.

As shown in FIG. 3, the right end of the horizontal portion 94a is in contact with the rear end 91b of the first partition member 91. Therefore, the inlet gas space 71A and the rear wall gas space 73 are separated by the horizontal portion 94a and are not continuous.
On the other hand, since the horizontal portion 94a does not extend between the first partition member 91 and the second partition member 92, the outlet gas space 71B and the rear wall gas space 73 are continuous.

  The upper end of the vertical portion 94b is in contact with the lid 80 that closes the upper part of the left wall gas space 74. Therefore, the left wall gas space 74 and the rear wall gas space 73 are separated by the vertical portion 94b and are not continuous.

The fifth partition member 95 is disposed in the right wall gas space 75 and extends in the up-down direction.
The upper end 95a of the fifth partition member 95 is in contact with the right flange 61a of the inner wall 61.
In addition, the lower side of the fifth partition member 95 is notched. For this reason, the second communication port 102 that connects the front wall gas space 72 and the right wall gas space 75 is formed.

Note that the rear part of the right flange 61 a of the inner wall 61 extends above the right wall gas space 75. A first notch 106 is formed at the rear of the right flange 61a.
In the lid 80, a third communication port 103 is formed behind the right edge of the bottom plate 81. For this reason, the right wall gas space 75 and the upper wall gas space 76 are continuous via the third communication port 103.

The sixth partition member 96 is disposed in the rear wall gas space 73 and extends in the up-down direction.
The upper end 96 a of the sixth partition member 96 is in contact with the rear flange 61 b of the inner wall 61.
The lower end 96 b of the sixth partition member 96 is in contact with the rear end 92 b of the second partition member 92. Therefore, the rear wall gas space 73 and the right wall gas space 75 are partitioned by the sixth partition member 96 and are not continuous.

In addition, a second notch 107 is formed on the left portion of the rear flange portion 61b of the inner wall portion 61.
In the lid 80, a fourth communication port 104 is formed on the rear edge side of the bottom plate 81. Therefore, the upper wall gas space 76 and the rear wall gas space 73 are continuous via the fourth communication port 104.

The seventh partition member 97 is disposed at the center in the left-right direction in the upper wall gas space 76 and extends in the front-rear direction.
The front end of the seventh partition member 97 is not in contact with the side wall 82.
The rear end of the seventh partition member 97 is in contact with the side wall 82.
Therefore, the upper wall gas space 76 has a substantially U-shaped path from the third communication path 103 to the fourth communication port 104.

Next, the path of the gas flow path 50 of the heat recovery casing 30 will be described.
As shown in FIG. 4, first, the oxidizing gas enters the inflow gas space 71A through the inflow port 51 and flows to the lower side of the left wall gas space 74 (see arrow B1).
Next, the oxidant gas flows upward from the lower portion of the left wall gas space 74 (see arrow B2), passes through the first communication port 101, and enters the front wall gas space 72 (see arrow B3).

  Next, the oxidizing gas flows obliquely from the upper left to the lower right of the front wall gas space 72 (see arrow B4), passes through the second communication port 102, and flows into the right wall gas space 75 (arrow). B5).

  Next, as shown in FIG. 3, the oxidizing gas flows obliquely from the front lower part to the rear upper part of the right wall gas space 75 (see arrow B <b> 6), passes through the third communication port 103, and passes through the upper wall. The gas enters the gas space 76 (see arrow B7).

  Next, the oxidizing gas moves in a U-shape in the upper wall gas space 76 (see arrow B8), and flows through the fourth communication port 104 into the rear wall gas space 73 (see arrow B9).

  Next, the oxidizing gas flows from the upper part to the lower part of the rear wall gas space 73 (see arrow B10), and flows from the lower part of the rear wall gas space 73 to the rear part of the outlet gas space 71B (see arrow B11).

  Then, as shown in FIG. 4, the oxidizing gas that has flowed from the rear to the front of the outflow gas space 71B flows through the gas outlet 54 into the heat recovery casing 30 (see arrow B12). ), And is supplied to the BOP 20 of the fuel cell module 10.

<Heat insulation structure of fuel cell module>
Subsequently, a heat insulating structure of the fuel cell module 10 according to the embodiment of the present invention will be described with reference to FIG.

  As shown in FIG. 2, the heat recovery casing 30 includes the main body 60 and the lid 80, and includes an inner housing 30 </ b> A and an outer housing 30 </ b> B. The inner housing 30A is made of metal (for example, SUS) formed of an inner bottom wall portion 31, a front wall portion 32, a rear wall portion 33, a left wall portion 34, a right wall portion 35, and an upper wall portion 36. It is a can body. The outer housing 30B is larger than the inner housing 30A, which includes an outer bottom wall 31, a front wall 32, a rear wall 33, a left wall 34, a right wall 35, and an upper wall 36. It is a metal (for example, SUS) can body. The fuel cell module 10 is housed in the inner housing 30A. The outer housing 30B houses the inner housing 30A.

  The heat insulating structure of the fuel cell module 10 includes an inner heat insulating layer 111, an intermediate heat insulating layer 112, and an outer heat insulating layer 112.

≪Insulation layer inside≪
The inner heat insulating layer 111 is a heat insulating layer in a high temperature range, and is made of a granular heat insulating material provided so as to surround the fuel cell module 10. In the present embodiment, the inner heat-insulating layer 111 is made of a granular heat-insulating material filled in the inner housing 30A. As the granular heat insulating material, a granular microtherm or the like can be suitably used.

≪Intermediate insulation layer≫
The intermediate heat insulating layer 112 is a heat insulating layer in a medium temperature range, and is a heat insulating layer formed by air formed between the inner heat insulating layer 111 and the outer heat insulating layer 113. In the present embodiment, the intermediate heat insulating layer 112 is configured between the inner housing 30A and the outer housing 30B.

  The intermediate heat insulating layer 112 has a gas flow path 50 through which an oxidizing gas (air) supplied through the BOP 20 flows to the cathodes of the plurality of fuel cells stacked in the fuel cell stack 12. Is provided.

≪Outer insulation layer≫
The outer heat-insulating layer 113 is a heat-insulating layer in a low-temperature region, is formed of a block heat-insulating material, and is a heat-insulating layer having a housing shape. The outer heat insulating layer 113 is provided outside the inner heat insulating layer 111 and the intermediate heat insulating layer 112, and houses the fuel cell module 10 and the inner heat insulating layer 111. In the present embodiment, the outer heat insulating layer 113 contains the outer housing 30B. The inner space of the outer heat insulating layer 113 has the same shape as the outer shape of the outer housing 30B, and the inner surface of the outer heat insulating layer 113 is in contact with the outer surface of the outer housing 30B. As the block heat insulating material, that is, the outer heat insulating layer 113, a resin heat insulating material, a calcium silicate heat insulating material, a fumed SiO ₂ nano heat insulating material, or the like can be selectively used in consideration of a temperature range, a heat radiation amount, a cost, and the like.

  In the outer heat-insulating layer 113, holes are formed in portions corresponding to the inflow port 51, the gas burner 24a, and the like to allow these to pass therethrough.

The heat insulating structure of the fuel cell module 10 according to the embodiment of the present invention can realize a suitable heat insulating performance by a three-layer heat insulating structure, and is compact because the intermediate heat insulating layer 112 made of air is provided in the middle. And heat insulation performance can be compatible.
In addition, the heat insulating structure of the fuel cell module 10 can improve the heat insulating performance because the granular heat insulating material can be provided to the details of the complicated shape of the fuel cell stack 12 and the peripheral device (BOP 20) of the fuel cell module 10. .
Further, in the heat insulating structure of the fuel cell module 10, since the inner heat insulating layer 111 is made of the granular heat insulating material, the heat insulating structure of the fuel cell module 10 has a complicated shape compared to the case where the inner heat insulating layer 111 is made of the block heat insulating material. No processing is required to cope with this, and low cost can be realized.
Further, since the heat insulating structure of the fuel cell module 10 includes the inner heat insulating layer 111, the outer heat insulating layer 113 only needs to have heat insulating performance in a relatively low temperature range. It is possible to adopt.

  Further, the heat insulation structure of the fuel cell module 10 is provided with the heat dissipation recovery housing 30 having a double structure including the inner housing 30A and the outer housing 30B, so that the inner housing 30A is filled with the granular heat insulating material. By doing so, the inner heat insulating layer 111 can be easily formed, and the intermediate heat insulating layer 112 made of air can be easily formed between the inner housing 30A and the outer housing 30B.

  Further, in the heat insulating structure of the fuel cell module 10, since the gas flow path 50 is provided in the intermediate heat insulating layer 112, the oxidizing gas performs heat exchange to reduce waste heat discharged from the inner heat insulating layer 111 to the outside. Since the waste gas is recovered, the oxidizing gas can be heated using the waste heat.

  In addition, according to the above-described heat recovery casing 30, the oxidizing gas flows through the gas flow path 50 including the bottom wall gas space 71 to the top wall gas space 76 and is heated. In other words, the oxidizing gas recovers the heat radiation energy from all the walls constituting the heat recovery casing 30.

  Further, in the front wall gas space 72, the right wall gas space 75, and the upper wall gas space 76, the oxidant gas moves obliquely or in a U-shape, so that the path of the oxidant gas is relatively small. It is longer (see arrows B4, B6, B8). For this reason, the oxidizing gas recovers more heat radiation energy.

Further, the flange 24b of the gas burner 24a is fixed to the inner wall 61 constituting the left wall 34, and the gas burner 24a extends into the left wall gas space 74. Therefore, the oxidant gas flowing through the left wall gas space 74 recovers a large amount of thermal energy from the inner wall portion 61 and the gas burner 24a.
As described above, the oxidizing gas heated to a high temperature is supplied to the BOP 20.

  In addition, according to the heat recovery casing 30, since the oxidizing gas recovers the heat energy of each wall portion, it is difficult for the heat energy to be transmitted to the external space of the heat recovery casing 30. In other words, even if the heat recovery casing 30 is installed near the outer wall of a building or in a limited space in a condominium, it is difficult for heat energy to be transmitted to the outer wall of the building. As described above, the heat recovery casing 30 can be installed close to the outer wall of the building, and the installation space can be reduced.

As described above, the heat recovery casing 30 according to the embodiment has been described, but the present invention is not limited to the example described in the embodiment.
For example, in the above-described embodiment, the entire intermediate heat insulating layer 112 functions as the gas flow path 50. However, the gas flow path 50 made of a pipe or the like is provided in the intermediate heat insulating layer 112, and the air layer serving as the intermediate heat insulating layer 112 is provided. The oxidizing gas may be different from the oxidizing gas.
The inner space of the outer heat insulating layer 113 is set to be larger than that of the outer housing 30B, and a gap is provided between the outer heat insulating layer 113 and the outer housing 30B (between upper wall portions, between side wall portions, and the like). May be formed.
In the present embodiment, only the gas burner 24a of the exhaust gas combustor 24 is supported by the heat recovery casing 30, but the gas burner (not shown) of the startup combustor 25 is also used for heat recovery. You may comprise so that it may be supported by the housing | casing 30.
Further, the BOP 20 housed in the heat recovery casing 30 is a steam reforming type, but may be a partially oxidizing type or a type having both a steam reforming type and a partial oxidizing type. There is no particular limitation.

Reference Signs List 1 fuel cell system 10 fuel cell module 12 fuel cell stack 20 BOP (Balance Of Plant, peripheral equipment unit)
24 Exhaust gas combustor 24a Gas burner 24b Flange 30 Heat dissipation recovery housing (fuel cell heat dissipation recovery housing)
30A Inner case 30B Outer case 40 Coupling bracket (coupling part)
Reference Signs List 50 gas flow path 52 gas inflow port 54 gas outflow port 60 main body section 80 lid section 90 partition section 111 inner heat insulating layer (granular heat insulating material)
112 Intermediate insulation layer (air)
113 Outer insulation layer (block insulation material)
S1 First gap S2 Second gap

Claims (2)

A heat insulating structure for a fuel cell module having a fuel cell stack and a peripheral device unit,
An inner heat insulating layer made of a granular heat insulating material provided so as to surround the fuel cell module,
An outer heat-insulating layer, which is provided outside the inner heat-insulating layer and has a housing shape in which the fuel cell module and the inner heat-insulating layer are housed, is made of a block heat-insulating material;
With
An intermediate heat insulating layer by air is configured between the inner heat insulating layer and the outer heat insulating layer ,
The intermediate heat insulating layer is provided with a gas flow path through which an oxidizing gas supplied to the cathode of the fuel cell stack flows,
The peripheral device unit includes an exhaust gas combustor that burns exhaust gas discharged from the fuel cell stack,
A heat insulation structure for a fuel cell module , wherein a gas burner of the exhaust gas combustor extends into the gas flow path . An inner housing in which the fuel cell module is housed,
An outer housing in which the inner housing is housed,
With
The inner heat insulating layer is constituted by the granular heat insulating material filled in the inner housing,
The intermediate heat insulating layer is configured between the inner housing and the outer housing,
The heat insulating structure for a fuel cell module according to claim 1, wherein the outer housing is housed in the outer heat insulating layer having a housing shape.

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