JP5105288B2 - Insulation system for fuel cell - Google Patents

Description

The present invention relates to a thermal insulation system for a fuel cell incorporated in the fuel cell body, or more fuel cell power generation system consisting of the incidental device.

  The fuel cell power generation system uses natural gas, liquefied petroleum gas (LPG), fossil fuels such as kerosene, synthetic fuels such as methanol and dimethyl ether, and biofuels such as ethyl alcohol. This is a device that directly converts electrical energy into electrical energy and extracts it. It has high energy conversion efficiency without being restricted by Carnot cycle, can clean energy conversion because there is no combustion process, and vibrates during operation. It is attracting attention as the next generation power generation system. Furthermore, it attracts attention as a compact power generation system that can easily secure important power as a lifeline in the event of a disaster.

  A fuel cell power generation system generally includes a fuel cell main body and an auxiliary device for the fuel cell main body.

  The fuel cell body is composed of an electrolyte, an air electrode, and a fuel electrode. Oxygen gas is supplied as an oxidant to the air electrode side, and hydrogen gas is supplied to the fuel electrode side. Electric energy is generated by an electrochemical reaction in which oxygen ions and hydrogen ions are combined with each other through an electrolyte.

  There are various types of fuel cells such as solid oxide fuel cells, molten carbonate fuel cells, phosphoric acid fuel cells, and polymer electrolyte fuel cells. The operating temperature of each fuel cell is about 800 to 1000 ° C. for a solid oxide fuel cell, about 650 ° C. for a molten carbonate fuel cell, about 250 ° C. for a phosphoric acid fuel cell, and a solid polymer fuel. The battery is about 80 ° C.

  Thus, depending on the type of fuel cell, there is the above-mentioned optimum operating temperature, and unless this operating temperature is maintained, a predetermined electrochemical reaction is not performed and power generation efficiency is reduced.

  On the other hand, the auxiliary devices of the fuel cell main body include a fuel gas processing device, a fuel gas mixer, a heat exchanger, a fuel gas blower, an oxidant gas blower, and the like. Appropriate specifications and optimum combinations of the accessory devices are considered as appropriate depending on the type of fuel cell, usage conditions, and the like.

  For example, the fuel gas processing apparatus is composed of a reformer, a CO converter, and the like. Generally, the operating temperature of the reformer is about 700 to 800 ° C., and the operating temperature of the CO converter is about 350 ° C. Unless this operating temperature is maintained, the predetermined reforming reaction and shift reaction are not performed, and a fuel gas having a predetermined composition cannot be generated. Heat exchangers and the like also have operating temperatures suitable for each, and it is necessary to maintain that temperature.

  In the case of a solid polymer type (PEFC) fuel cell, this uses a solid polymer ion exchange membrane as an electrolyte, oxygen gas is supplied as an oxidant to the air electrode side, and hydrogen is supplied to the fuel electrode side. When gas is supplied and hydrogen ions move in the ion exchange membrane of the solid polymer, an electrochemical (battery) reaction is caused to generate electricity. In this case, when using city gas / LPG / kerosene other than hydrogen as fuel gas for practical use such as home use, small business use, automobile use, portable use, etc., using a fuel reformer, for example, steam Purification of hydrogen-rich reformed fuel gas by a reforming method has been performed. The hydrogen gas produced here is made to generate electricity by electrochemically reacting with air, which is an oxidizing gas, in a polymer electrolyte (PEFC) power generation stack.

  However, even a 1 KW class household fuel cell system requires an adiabatic system because the catalyst activation temperature is usually around 750 ° C. However, if the same commercial power generation system as a commercial power generation system of several tens of watts is adopted as it is, efficiency is poor. Moreover, as a fuel cell system for home use, the installation space must naturally be made as compact as possible. Therefore, it is desired to provide a more efficient heat insulation system at a low cost.

  Conventionally, in order to maintain the operating temperature of the fuel cell main body and its auxiliary devices, a heat insulating structure has been made by filling a ceramic-based heat insulating material around the fuel cell main body and its auxiliary devices.

  For example, Patent Document 1 proposes surrounding the fuel cell main body and its associated devices with a vacuum heat insulating structure. Further, Patent Document 2 proposes that a ceramic-based heat insulating material layer and a vacuum heat insulating structure are used in combination to surround the periphery of a fuel cell main body and its associated devices.

  Furthermore, in Patent Document 3, the reformer and related equipment are combined as one unit, and a vacuum heat insulating container in which a vacuum heat insulating layer is formed between the inner cylinder and the outer cylinder is covered and covered. This makes it possible to configure a fuel reformer that uses the inside of the vacuum insulation container as a flow path for the combustion gas of the reformer, eliminating the need for filling with a heat insulating material such as ceramic fibers, and reducing the volume of the heat insulation layer, thereby reducing the size of the device. In addition, it has been proposed to improve the thermal efficiency.

  Patent Document 4 proposes a heat insulating structure for a furnace filled with a gas containing water vapor. Here, the heat insulating material arranged in the first layer made of an inorganic heat insulating material having closed cells such as a foamed ceramic body and a foamed glass body in order from the inside of the casing toward the inside of the furnace, and the first layer There has been proposed a heat insulation system for a fuel cell arranged so as to include a heat insulating material arranged in the second layer inside the first layer and a heat insulating material arranged in the third layer inside the second layer. Here, the heat insulating material arranged in the second layer is superior to the heat insulating material arranged in the third layer, and the heat insulating material arranged in the first layer and the heat insulating material arranged in the second layer The thickness of the heat insulating material arranged in the third layer is designed so that the boundary temperature between the heat insulating material arranged in the first layer and the heat insulating material arranged in the second layer is higher than the dew point temperature of the exhaust fuel gas. It is said that heat insulation performance can be prevented from deteriorating due to condensation of water vapor.

  And as a heat insulating material itself, patent document 5 is disclosing the microporous heat insulating material which has the heat insulation characteristic which can be utilized in the temperature range from -273 degreeC to a maximum of 950 degreeC. It is conceivable to use this microporous heat insulating material as a heat insulating structure of a high-temperature heating element such as a fuel cell and a fuel cell reformer.

JP 2001-229949 A JP 2002-280041 A JP 2003-327405 A JP 2008-16264 A Japanese Patent Laid-Open No. 7-10651

  However, since it is necessary to increase the thickness of the heat insulating structure layer if it is intended to maintain such a high operating temperature by filling the ceramic-based heat insulating material around the fuel cell main body and its associated devices, Battery insulation systems have become massive. Therefore, in particular, compactness is required in order to easily secure power important as a lifeline at the time of a disaster. Especially when it is used as a household power generation system, space saving, that is, compaction of the portion occupied by heat insulating material is required. Therefore, it cannot be adopted as a heat insulation structure for a fuel cell power generation system.

  In the fuel cell power generation device described in Patent Document 1, the surroundings of the fuel cell main body are surrounded by a vacuum heat insulating structure, so that the heat insulating structure layer can be thinned, but the wall surface forming the airtight space is subjected to external pressure. It is necessary to use a high-strength metal material. However, since the wall surface that forms the airtight space directly affected by the high operating temperature of the fuel cell body becomes high temperature, the metal material used for this wall surface is susceptible to high-temperature oxidative corrosion, and is subject to external pressure, There is a risk that the vacuum insulation structure may be broken due to breakage resulting in loss of airtightness. In addition, when the heat resistance of the welded portion of the metal material is insufficient, the wall surface may be deformed due to distortion or breakage of the welded portion, and the vacuum heat insulating structure may be broken.

  In the fuel cell described in Patent Document 2, a heat insulating material layer is provided inside the airtight space forming the vacuum heat insulating structure to surround the periphery of the fuel cell main body and its associated devices. Although the temperature is somewhat lowered, if the thickness of the heat insulating material layer is insufficient, the wall surface forming the hermetic space becomes high temperature, which may cause breakage or deformation and break the vacuum heat insulating structure.

  In the fuel cell power generation system described in Patent Document 3, the reformer and related equipment are combined as one unit, and a vacuum heat insulating container in which a vacuum heat insulating layer is formed between the inner cylinder and the outer cylinder is provided in this unit. In order to cover the cover, an airtight structure that forms an airtight space and maintenance work are required. In addition, since heat resistance is required, the material used must be a sealed container using a wall plate made of a heat-resistant metal, such as stainless steel, and this vacuum insulation structure can be reduced in weight and size. There is a problem in terms of weight when used in a stationary fuel cell for home use, and it is necessary to take measures against thermal distortion on the inner and outer surfaces of the wallboard.

  In the heat insulating structure of the fuel cell described in Patent Document 4, the heat insulating material is not formed in order from the outside of the furnace, but the heat insulating material arranged in the second layer is the heat insulating material arranged in the third layer. The heat insulating material has a three-layer structure with better heat insulation. However, since this heat insulating material layer does not constitute a heat insulating structure with low thermal conductivity, the thickness of each layer of the heat insulating material is not suitable for a heat insulating structure against high temperatures such as a fuel cell and a fuel cell reformer. It is necessary to take sufficient thickness, so that the volume of the heat insulating material layer becomes large.

Next, the microporous heat insulating material disclosed in Patent Document 5 can be formed into a board shape, but its bulk density needs to be 0.22 to 0.35 g / cm ^3. It cannot be made into a sheet with properties. Therefore, when this is used as a heat insulation structure of a high-temperature heating element such as a fuel cell and a reformer of the fuel cell, a machine such as a cylinder is formed so as to follow the shape of the main body of the fuel cell or the reformer. It must be processed or manufactured with a dedicated mold. For this reason, the yield at the time of manufacture is bad, and since a large-scale manufacturing apparatus is required, there is a problem that it is difficult to change the design.

  The present invention has been made to solve such problems of the prior art, and an object thereof is to provide an inexpensive and lightweight heat insulation system for a fuel cell that does not require machining.

  As a result of repeating various studies and experiments regarding the heat insulation structure of the fuel cell power generation system, the present inventor has obtained the knowledge shown in the following (a) to (g).

  (a) In order to reduce the thickness of the entire heat insulating structure of the fuel cell heat insulating system, a vacuum heat insulating structure that surrounds the fuel cell main body and its associated devices may be employed. However, as described above, since the wall surface forming the hermetic space becomes high temperature in the vacuum heat insulating structure, the material used for the wall surface is likely to be thermally damaged or deformed, and the vacuum heat insulating structure may be broken. As a lack of reliability.

  (b) On the premise that the airtight space of the vacuum heat insulation structure is not used, if one tries to construct a heat insulation system for a fuel cell, one or more kinds of heat insulation materials are provided around the fuel cell main body and / or its auxiliary devices. Will be filled. However, if a thermal insulation system for a fuel cell is constructed using only the thermal insulation material as in the thermal insulation structure of the cited document 4, the insulation thickness for the fuel cell is inevitably increased because the filling thickness of the thermal insulation material must be increased. It becomes a thing.

  (c) As a result of various studies to reduce the filling thickness of the heat insulating material used in the heat insulation system for fuel cells, the inventor has found that `` oxidant gas and fuel gas are supplied into the battery chamber under a high temperature operating temperature environment. First, consisting of a flexible inorganic heat insulating material, in order from the inside, around the fuel cell main body and / or its auxiliary device that is configured to electrochemically react the oxidant gas and the fuel gas to obtain electric power. A heat insulating system for a fuel cell, comprising a second heat insulating material layer made of a flexible airgel heat insulating material, and a third heat insulating material layer made of a flexible inorganic heat insulating material. I came up with a good idea.

  This is because, as a first reason, in order to install the heat insulating material around the fuel cell main body and / or its auxiliary device, the installation work is not facilitated if it is a board-like molded product, but it has flexibility. This is because it was thought that the installation work would be faster if it was a heat insulating material. And as a second reason, the overall filling thickness of the heat insulating material can be reduced by sharing the function of the heat insulating material installed around the fuel cell main body and / or its ancillary devices with three additional heat insulating materials. Because I thought.

  In other words, the first heat insulating material layer, which is the innermost layer at the highest temperature, is expected to have a certain degree of heat insulation effect, but can withstand high temperatures of about 1000 ° C., and heat resistance is given priority. Select a heat insulating material, and select a heat insulating material capable of exerting a significant heat insulating property for the second heat insulating material layer of the outer layer, and a third heat insulating material layer as the outermost layer on the surface thereof. I thought that it would be good if it is a heat insulating material that does not cause burns even if it is touched.

  (d) A flexible inorganic heat insulating material can be used for the first heat insulating material layer, and ceramic fibers made of silica fibers or the like are preferable. This not only can withstand high temperatures of 1000 ° C., but is flexible so that it can be wound close to the outer periphery of the fuel cell body.

  (e) And as a 2nd heat insulating material layer, the microporous heat insulating material currently disclosed by the said patent document 5 is mentioned from a viewpoint that the heat insulation effect is large even if the filling thickness is reduced. However, when considering workability, microporous heat insulating materials have many problems.

  Therefore, as the second heat insulating material layer, a material having flexibility from the viewpoint of workability is preferable. However, from the viewpoint that heat resistance is not so much required, as a result of further examination, a flexible airgel heat insulating material is suitable. I found out.

  Here, the flexible airgel heat insulating material is a silica porous body having an open cell structure having pores of 1 to 20 nm, which is formed by solating silica in a solution, removing the water with a supercritical fluid, and drying. It is made of a heat insulating element that is distributed in a non-woven fabric and has a porosity of 97% or more. This heat insulating element is made of inorganic fibers such as glass and silica. For example, the silica material is distributed in the nonwoven fabric by a manufacturing method as shown in JP-T-2007-524528, so that the porosity is 97% or more. be able to. In addition, as a nonwoven fabric, glass fiber, PET fiber, OPAN fiber, etc. can be used.

  The airgel substance made of this silica material has, for example, a porosity of about 80% by volume or more and a pore size of about 0.5 to 500 nanometers, as described in paragraph No. 0038 of JP-T-2003-512277. A material having pores that are in range, and the solvent used for gelation can be removed from the material by drying without destroying or substantially shrinking the pore structure during drying It can be made from any gel-forming material. This drying can be achieved by supercritical extraction, air drying, freeze drying, vacuum evacuation, and the like. Preferably, the aerogel is made by supercritical extraction of the solvent used to make the starting gel (or any liquid in place of the solvent). The porosity of the airgel is preferably at least 85% by volume, more preferably about 90% by volume or more.

  (f) Next, a flexible inorganic heat insulating material can be used for the third heat insulating material layer, and ceramic fibers made of silica fibers or the like are preferable. Alternatively, inexpensive glass wool may be used. (g) Then, considering the work to be installed around the fuel cell main body and / or its auxiliary device, it is preferable that the flexible heat insulating material has a sheet-like shape because workability is good. As a procedure of the operation of installing the flexible heat insulating material around the fuel cell main body and / or its auxiliary device, for example, the edge of the sheet-shaped heat insulating material is abutted against each other to form a ring. Can be wound up. This procedure is applicable to both flexible inorganic insulation and flexible airgel. Or the edge of a sheet-shaped heat insulating material may be overlapped, and the first to third heat insulating material layers may be wound in order in a spiral manner.

  The present invention has been completed based on the above findings, and the gist thereof is as shown in the following (1) to (8). Hereinafter, they are referred to as “present invention 1” to “present invention 8”, respectively, and sometimes referred to as “present invention”.

(1)
A fuel cell main body or an auxiliary device for supplying power by supplying an oxidant gas and a fuel gas into a battery chamber under a high temperature operating temperature environment and electrochemically reacting the oxidant gas and the fuel gas. A first heat insulating material layer made of a flexible inorganic heat insulating material, a second heat insulating material layer made of a sheet-shaped flexible airgel heat insulating material, and a flexible inorganic heat insulating material, around the fuel cell , in order from the inside. A heat insulating system for a fuel cell, comprising a third heat insulating material layer made of a material.

(2) The heat insulation system for a fuel cell according to (1), wherein the flexible inorganic heat insulation material has a sheet shape.

(3) The sheet-shaped flexible inorganic heat insulating material and / or the sheet-shaped flexible airgel heat insulating material are wound to form a single-layer structure or a laminated structure of two or more layers. The fuel cell thermal insulation system according to (1) or (2) above.

(4) The sheet-shaped flexible inorganic heat insulating material and / or the edge of the sheet-shaped flexible airgel heat insulating material are abutted against each other, and each layer is wound in an annular shape, The fuel cell thermal insulation system as described in (3) above.

(5) The edge of the sheet-shaped flexible inorganic heat insulating material and the edge of the sheet-shaped flexible airgel heat insulating material overlap so that the first to third heat insulating material layers spirally in order. (3) The fuel cell heat insulation system according to (3) above.

  (6) The heat insulation system for a fuel cell according to any one of (1) to (5), wherein the flexible inorganic heat insulating material is a ceramic fiber.

  (7) The heat insulation system for a fuel cell according to any one of the above (1) to (6), wherein the flexible inorganic heat insulation material is glass wool.

  (8) The flexible inorganic heat insulating material of the first heat insulating material layer is a ceramic fiber, and the flexible inorganic heat insulating material of the third heat insulating material layer is glass wool, (1) to (5) any one of the fuel cell thermal insulation systems.

  ADVANTAGE OF THE INVENTION According to this invention, machining is unnecessary and it can provide the cheap and lightweight heat insulation system for fuel cells.

  Embodiments of a heat insulation system for a fuel cell according to the present invention will be described below with reference to the drawings. Although the outer shape of the fuel cell and the reformer body of the fuel cell shown in this embodiment is cylindrical and each layer is concentrically centered on the one-dot chain line, A shape such as a rectangular parallelepiped combined with a plane or a shape combined with a curved surface may be appropriately selected and used.

  FIG. 1 shows an example of a heat insulation system for a fuel cell according to the present invention. The upper figure shows the perspective arrangement of each heat insulation layer, and the lower figure shows the temperature distribution in the heat insulation structure.

  The main body 1 of the fuel cell or the reformer of the fuel cell is a high-temperature heat source of 700 ° C. to 750 ° C., and the outer shape is formed in a substantially cylindrical shape. The second heat insulating material layer 3 and the third heat insulating material layer 4 are wound in a substantially concentric shaft shape and are adhered and laminated. In this case, the 1st heat insulating material layer 2, the 2nd heat insulating material layer 3, and the 3rd heat insulating material layer 4 become a flexible structure so that it can deform | transform into an annular shape with a heat insulator element. . Further, as a method of fixing the first heat insulating material layer 2, the second heat insulating material layer 3, and the third heat insulating material layer 4, the first heat insulating material layer 2 and the third heat insulating material layer 4 are silicic acid. A method of forming by impregnating an inorganic binder such as soda or colloidal silica or a method of winding and holding a belt-like glass cloth around the outermost surface of the third heat insulating material layer 4 may be employed.

  The first heat insulating material layer 2 is a heat insulating element made of an inorganic material that can withstand a high temperature of 1000 ° C. such as ceramic fiber or silica fiber, and is flexible, so that it is in close contact with the outer periphery of the fuel cell main body 1. Can be wound up. The thickness of the first heat insulating material layer 2 is, for example, about 5 mm to 35 mm in the case of a 1 KW class small household fuel cell system.

The second heat insulating material layer 3 was made of Aspen Aerogel (trade name: Pyrogel). This was a roll having a thickness of 6 mm, a width of 1.47 m, and a length of 75 m, a thermal conductivity of 14, and a density of 120 kg / m ³ . A glass mat is used as the reinforcing material (nonwoven fabric).

  The thickness of the flexible airgel heat insulating material used as the second heat insulating material layer 3 is, for example, in the case of a 1 KW class small household fuel cell system, a sheet-like material having a thickness of about 6 mm is used in two to five layers. It can be used in a state where the layers are circularly stacked to a thickness of 12 to 30 mm.

  Next, the 3rd heat insulating material layer 4 can use a flexible inorganic heat insulating material, and is a heat insulator element which consists of ceramic fibers, such as a silica fiber. Alternatively, inexpensive glass wool may be used. It is flexible and can be rolled so as to be in close contact with the outer periphery of the second heat insulating material layer 3. The thickness of the third heat insulating material layer is, for example, about 4 mm to 30 mm in the case of a 1 KW class small household fuel cell system.

  FIG. 2 is a cross-sectional view (top view) showing an example of a winding procedure of each heat insulation layer of the heat insulation system for a fuel cell according to the present invention.

  The first heat insulating material layer 2, the second heat insulating material layer 3, and the third heat insulating material layer 4 are concentric so as to be in close contact with the outer periphery of the main body 1 of the substantially cylindrical fuel cell or fuel cell reformer in order. It is wound in the shape of a shaft. The first heat insulating material layer 2 is formed by winding a heat insulator element having a thickness of about 20 mm around the main body 1, joining the edge 2 </ b> A and closing it in an annular shape, and the outer periphery of the main body 1 of the fuel cell or fuel cell reformer. Adhere to. Similarly, the second heat insulating material layer 3 is a heat insulating element having a thickness of about 6 mm, and the three second heat insulating material layers 31, 32, 33 are sequentially arranged from the inner side to the respective edges 31A, 32A and 33A. Are joined in an annular shape with a thickness of 18 mm, closed in an annular shape and wound to adhere to the outer periphery of the first heat insulating material layer 2. In this case, although illustrated as a three-layer second heat insulating material, the number of layers may be appropriately selected such as four layers. The third heat insulating material layer 4 is a heat insulating element having a thickness of about 10 mm to 15 mm, and the two third heat insulating material layers 41 and 42 are annularly formed by joining the respective edges 41A and 42A. And are wound in an annular shape and are brought into close contact with the outer periphery of the second heat insulating material layer 3. In this case, the third heat insulating material layer 4 may be composed of a single heat insulating element having a thickness of about 25 mm. The first heat insulating material layer 2, the second heat insulating material layer 3, and the third heat insulating material layer 4 are joined in a circular shape by joining their respective edges, and are concentrically formed on the substantially cylindrical body 1. When turning, the thermal insulation is improved by displacing each edge position so as not to overlap in the radial direction.

  FIG. 3 is a cross-sectional view (top view) showing another example of the winding procedure of each heat insulation layer of the heat insulation system for a fuel cell according to the present invention.

  The first heat insulating material layer 2, the second heat insulating material layer 3, and the third heat insulating material layer 4 are sequentially in close contact with the outer periphery of the main body 1 of the substantially cylindrical fuel cell or the reformer of the fuel cell. It is a turn. The first heat insulating material layer 2 is wound around the main body 1 so that the heat insulating element having a thickness of about 20 mm is overlapped with the start end 2B and the end 2C from the start end 2B toward the end 2C. The second heat insulating material layer 3 is a three-layer heat insulating material made of a heat insulating element having a thickness of about 6 mm. The second heat insulating material layer 3 is provided between the start end 2A and the terminal end 2B of the first heat insulating material layer 2. The material layer 3 is spirally wound 3 times so as to cover the outer periphery of the first heat insulating material layer 2 with the start end 3B interposed therebetween and laminated so as to have a thickness of 18 mm. The third heat insulating material layer 4 is a two-layer heat insulating material made of a heat insulating element having a thickness of about 10 mm to 15 mm, and the first heat insulating material from the start end 4B so as to sandwich the terminal end 3C of the second heat insulating material layer 3. The material layer 2 is spirally wound so as to cover the outer periphery of the material layer 2, and the terminal end 4C is laminated so as to have a thickness of about 20 mm to 30 mm as the outermost peripheral surface.

  Next, in order to confirm the temperature distribution of the heat insulating structure in the fuel cell heat insulating system, the first heat insulating material layer 2 and the second heat insulating material layer 3 are taken using the substantially cylindrical main body of the reformer as an example. And the third heat insulating material layer 4 were sequentially wound around the main body 1 in a spiral manner (see FIG. 3) to prepare two examples having a heat insulating structure.

  In Example 1, the first heat insulating material layer is a heat insulating element made of one layer of silica fiber having a thickness of 18 mm, and the second heat insulating material layer is made of three heat insulating elements having a thickness of 6 mm. A heat insulating element having a thickness of 18 mm, and the third heat insulating material layer was wound in a spiral shape as a heat insulating element having a thickness of 18 mm and made of one layer of glass wool.

  In Example 2, the first heat insulating material layer is a heat insulating element made of one layer of ceramic fiber having a thickness of 32.5 mm, and the second heat insulating material layer is a single layer of heat insulating element having a thickness of 6 mm. Then, the heat insulating element having a thickness of 18 mm and the third heat insulating material layer having a thickness of 12.5 mm and being formed of a single layer of ceramic fibers were spirally wound.

  As shown in FIG. 1, the temperature of the part A between the outer peripheral surface of the main body 1 and the first heat insulating material layer 2, the part between the first heat insulating material layer 2 and the second heat insulating material layer 3. The temperature of B, the temperature of the part C between the second heat insulating material layer 3 and the third heat insulating material layer 4, and the temperature of the part D on the surface of the third heat insulating material layer 4 which is the outermost surface of the main body 1 Was measured. At that time, the outside air temperature was 25 ° C., and the material thickness of the heat insulating element of each heat insulating material was selected in two ways, and the temperature distribution shown in Table 1 was obtained as Example 1 and Example 2. As a result, a predetermined temperature was obtained at the portion D on the surface of the third heat insulating material layer 4.

  Since the temperature of the part D on the outermost surface of the main body is desired to be 60 ° C. or less, as a comparative example, a microporous molded body, that is, a microporous shaped body, is processed to a thickness of 62.5 mm, and a reformer The temperature of the part D on the outermost surface of the main body was measured. As a result, the temperature of the portion D on the outermost surface of the main body that was satisfactory in Examples 1 and 2 of the present application was obtained.

  In addition, the 1st heat insulating material layer 2 shown by this-application embodiment is wound around the outer periphery of the main body 1, the 2nd heat insulating material layer 3 is wound around the outer periphery of the 1st heat insulating material layer 2, and the 3rd heat insulating material layer As a method of winding 4 around the outer periphery of the second heat insulating material layer 3, although not shown, the core tube corresponding to the outer diameter of the main body 1 of the fuel cell or reformer is rotated to rotate the first heat insulating material layer 2. In order to improve the productivity by continuous production, it is possible to meet the price required by the industry.

  As described above, the heat insulation system for a fuel cell according to the present invention includes a first flexible heat insulator element made of an inorganic material on the outer periphery of at least one of the main body of the fuel cell and the reformer of the fuel cell. And a porous silica material having an open-cell structure with pores of 1 to 20 nm formed by solating silica in a solution and removing the moisture with a supercritical fluid and drying the solution in a nonwoven fabric. A second heat insulating material layer made of a flexible heat insulating element having a rate of 97% or more and a third heat insulating material layer made of a flexible heat insulating element made of an inorganic material, respectively, in order. Since the second heat insulating material layer is made of a material having a lower thermal conductivity with respect to temperature than the other heat insulating material layers, it is not necessary to be machined and is inexpensive and lightweight. An insulator element can be used. For example, by rotating the core tube corresponding to the outer diameter of the main body of the fuel cell or the main body of the reformer and laminating sequentially from the first heat insulating material, continuous production becomes possible and productivity is significantly improved, and the yield is also individual. It is improved because it does not require machining from the block, and can meet the price required by the industry.

  Further, the first heat insulating material layer is wound around the outer periphery of the main body to join the edge, the second heat insulating material layer is wound around the outer periphery of the first heat insulating material layer, and the edge is joined. A third heat insulating material layer is wound around the outer periphery of the second heat insulating material layer to join edges, and the first heat insulating material layer, the second heat insulating material layer, and the third heat insulating material layer are combined. The heat insulation effect is improved by laminating them in a closed ring in order and bringing them into close contact with the outer periphery of the main body so that each heat insulating material can be made into a ring without gaps.

  Furthermore, the first heat insulating material layer is spirally wound so that the starting end and the terminal end overlap the outer periphery of the main body, and the second heat insulating material layer is formed on the outer periphery of the first heat insulating material layer. And the third heat insulating material layer is spirally wound so that the start end and the terminal end overlap the outer periphery of the second heat insulating material layer. The first heat insulating material layer, the second heat insulating material layer, and the third heat insulating material layer are sequentially laminated in a closed ring shape and closely adhered to the outer periphery of the main body, thereby the first heat insulating material layer and the second heat insulating material. The work of laminating the layer and the third heat insulating material layer in order is facilitated, and the heat insulating effect can be improved because the heat insulating materials can be formed in an annular shape without any gap by being in close contact with the outer periphery of the main body.

  In addition, when the third heat insulating material layer is a heat insulating element made of glass wool, it is possible to provide a heat insulating structure with good winding work and low cost.

  ADVANTAGE OF THE INVENTION According to this invention, machining is unnecessary and it can provide the cheap and lightweight heat insulation system for fuel cells.

It is a conceptual diagram of the heat insulation system for fuel cells which concerns on this invention. It is sectional drawing (top view) which shows an example of the winding procedure of each heat insulation layer of the heat insulation system for fuel cells which concerns on this invention. It is sectional drawing (top view) which shows the other example of the winding procedure of each heat insulation layer of the heat insulation system for fuel cells which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Main body of fuel cell or fuel cell reformer 2 First heat insulating material layer 3 Second heat insulating material layer 4 Third heat insulating material layer

Claims (8)

A fuel cell main body or an auxiliary device for supplying power by supplying an oxidant gas and a fuel gas into a battery chamber under a high temperature operating temperature environment and electrochemically reacting the oxidant gas and the fuel gas. A first heat insulating material layer made of a flexible inorganic heat insulating material, a second heat insulating material layer made of a sheet-shaped flexible airgel heat insulating material, and a flexible inorganic heat insulating material, around the fuel cell , in order from the inside. A heat insulating system for a fuel cell, comprising a third heat insulating material layer made of a material. The heat insulation system for a fuel cell according to claim 1, wherein the flexible inorganic heat insulation material has a sheet shape. The sheet-shaped flexible inorganic heat insulating material and / or the sheet-shaped flexible airgel heat insulating material are wound to form a one-layer structure or a laminated structure of two or more layers. Item 3. The heat insulation system for a fuel cell according to Item 1 or 2 . The sheet-shaped flexible inorganic heat insulating material and / or the edge of the sheet-shaped flexible airgel heat insulating material are abutted to each other, and each layer is wound in an annular shape. A heat insulation system for a fuel cell as described in 1. The first to third heat insulating material layers are spirally wound in order so that the edge of the sheet-shaped flexible inorganic heat insulating material and the edge of the sheet-shaped flexible airgel heat insulating material overlap. The heat insulation system for fuel cells according to claim 3, wherein   The heat insulation system for a fuel cell according to any one of claims 1 to 5, wherein the flexible inorganic heat insulating material is a ceramic fiber.   The heat insulation system for a fuel cell according to any one of claims 1 to 6, wherein the flexible inorganic heat insulating material is glass wool. The flexible inorganic heat insulating material of the first heat insulating material layer is ceramic fiber, and the flexible inorganic heat insulating material of the third heat insulating material layer is glass wool. 5. A heat insulation system for a fuel cell according to any one of 5 to 5.

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