JP2002280041A - Fuel cell electric power generating system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel cell electric power generating system set with a heat insulating layer around respective peripheries of a fuel cell main body and its ancillary device to keep respective optimum temperature capable of solving a problem that a heat insulating material layer becomes thicker as driving temperature increases higher, capacity of the fuel cell main body or the ancillary device of the fuel cell main body increases or a surface area of the fuel battery main body or the ancillary device of the fuel cell main body increases as the heat insulating material layer becomes thicker and accordingly, a heat radiating area increases and heat radiating loss increases. SOLUTION: A vacuum heat insulating layer is set at least at a part of the heat insulating layer in the periphery of at least the fuel cell main body or the ancillary device of the fuel cell main body.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel cell power generation system, and more particularly, to a heat insulation structure of a fuel cell power generation system including a fuel cell main body and an auxiliary device for the fuel cell main body.

[0002]

2. Description of the Related Art A fuel cell power generation system generally comprises a fuel cell body and an auxiliary device for the fuel cell body.

[0003] There are various types of fuel cell bodies such as a solid oxide fuel cell, a molten carbonate fuel cell, a phosphoric acid fuel cell, and a polymer electrolyte fuel cell. 1000 ℃, about 650 ℃, about 250 ℃
And about 80 ° C. The fuel cell body has an air electrode and a fuel electrode basically formed so as to face the electrolyte.Generally, air is supplied to the air electrode as an oxidizing gas, and hydrogen gas is used as a fuel gas to the fuel electrode. Alternatively, when a hydrogen-rich gas is generally supplied, an electrochemical reaction occurs to generate electric power and heat. Depending on the type of the fuel cell, there is the above-mentioned optimum operating temperature, and if this operating temperature is not maintained, a predetermined power generation reaction is not performed and the power generation efficiency is reduced.

On the other hand, as ancillary devices of the fuel cell body, there are a fuel gas processing device, a fuel gas mixer, a heat exchanger, a blower for a fuel gas, a blower for an oxidizing gas, and the like. For the auxiliary device, optimal specifications and optimal combinations are appropriately examined depending on the type of fuel cell, usage conditions, and the like. For example,
The fuel gas treatment device is composed of a reformer, a CO shift converter, and the like.
The operating temperature of the O-transformer is said to be about 350 ° C. Unless this operating temperature is maintained, a predetermined reforming reaction and a shift reaction are not performed, and a fuel gas having a predetermined composition cannot be generated. It is important to maintain an appropriate operating temperature for other heat exchangers and the like.

[0005] In order to maintain the operating temperature of the fuel cell main body or the auxiliary device of the fuel cell main body, a heat insulating material layer is provided on the outer surface of the fuel cell main body or the auxiliary device of the fuel cell main body,
A method for reducing heat loss has been adopted. The selection of the heat insulating material and the thickness of the heat insulating material layer are made based on the relationship between the operating temperature of the fuel cell main body or the auxiliary device of the fuel cell main body and the outside air temperature of the installation environment.

[0006]

However, the higher the operating temperature is, the thicker the heat insulating material layer is, which increases the volume occupied by the fuel cell main body or the auxiliary device of the fuel cell main body. In addition, as the heat insulating material layer becomes thicker, the surface area of the fuel cell main body or ancillary devices of the fuel cell main body increases, which may increase the heat radiation area and increase the heat radiation loss. This tendency is remarkable when the size of the fuel cell in a high-temperature fuel cell (for example, a solid oxide fuel cell) is small, and there is a problem that the volume of the entire power generation system increases.

[0007]

According to a first aspect of the present invention, there is provided a fuel cell body including a fuel cell, equipment for supplying and exhausting fuel and the like to and from the fuel cell, A fuel cell power generation system comprising: an auxiliary device; wherein the fuel cell main body and the auxiliary device have a heat insulation layer around the fuel cell power generation system, and at least a part of the heat insulation layer has a vacuum heat insulation layer. I will provide a. According to the present invention, by providing a vacuum heat insulating layer on at least a part of the heat insulating layer of the fuel cell main body or the auxiliary device, the vacuum heat insulating layer has a lower thermal conductivity than a conventional ceramic heat insulating material, so that the fuel The thickness of the entire heat insulating layer such as the fuel cell body can be reduced while maintaining the operating temperature of the cell. Thereby, the volume of the system can be reduced, and the heat loss can be reduced because the surface area of the heat insulating layer can be reduced.

According to a second aspect of the present invention, in the heat insulating layer around the fuel cell main body and the auxiliary device of the fuel cell main body, the periphery of the portion having the highest operating temperature or the periphery of the fuel cell main body having the largest volume and the peripheral device thereof. A fuel cell power generation system characterized by having a vacuum heat insulating layer in at least a part of the heat insulating layer. According to the present invention, by providing a vacuum heat insulating layer in the vicinity of a portion where the temperature is highest in the system, the effect of reducing the thickness of the entire heat insulating layer by the vacuum heat insulating layer can be maximized, and the system volume can be efficiently reduced. it can. In addition, by providing a vacuum heat insulating layer near a portion such as a device where the portion surrounded by the heat insulating layer is the largest,
If the heat insulation layer can be made thinner, the volume that can be reduced increases. As a result, the volume of the entire system can be reduced, and the heat loss can be reduced because the surface area of the heat insulating layer can be reduced.

According to a third aspect of the present invention, there is provided a fuel cell power generation system characterized in that at least a part of the shape of the vacuum heat insulating layer is cylindrical. According to the present invention, for example, when the fuel cell main body or the auxiliary device has a cylindrical shape, if the vacuum heat insulating layer is cylindrical, the heat insulating layer of the fuel cell main body or the auxiliary device can be made the most compact, and the entire system Volume can be reduced.

A fourth aspect of the present invention provides a fuel cell power generation system, wherein at least a part of the vacuum heat insulating layer is of a panel type. For example, the size of the fuel cell body changes because the number of cells changes depending on the output scale. Further, when the size of the fuel cell body changes, the size required for the auxiliary device also changes. According to the present invention, in such a case, if the cross-sectional shape of the fuel cell main body or the auxiliary equipment is rectangular, the panel-type vacuum heat-insulating layer can be most compact by adjusting the side length of the cross-sectional shape, The volume of the entire system can be reduced.

A fifth invention provides a fuel cell power generation system, wherein at least a part of the vacuum heat insulating layer is a jacket type. According to the present invention, when the jacket-type vacuum heat insulating layer is formed according to the shape of the equipment to be kept warm, the heat insulating layer can be made compact naturally.

A sixth invention provides a fuel cell power generation system, wherein the fuel cell body is a solid oxide fuel cell. The operating temperature of a solid oxide fuel cell is close to 1000 ° C., which is the highest temperature among fuel cells.
Therefore, the heat insulating layer of the solid oxide fuel cell is very thick. According to the present invention, the effect of reducing the thickness of the heat insulating layer is increased by installing the vacuum heat insulating layer on the heat insulating layer of the solid oxide fuel cell body, and the volume of the system can be significantly reduced. Since the surface area can be reduced, heat dissipation loss can be reduced.

According to a seventh aspect of the present invention, there is provided a fuel cell power generation system, wherein the auxiliary device of the fuel cell main body is a fuel gas processing device. 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 ° C., and the operating temperature of the CO converter is about 350
It is said to be ° C. ADVANTAGE OF THE INVENTION According to this invention, the thickness of the whole heat insulation layer can be made thin, maintaining the operating temperature of a fuel gas treatment apparatus by providing a vacuum heat insulation layer in the heat insulation layer of a fuel gas treatment apparatus which becomes relatively high temperature. Thus, the volume of the device can be reduced, and the heat loss can be reduced because the surface area of the heat insulating layer can be reduced.

According to an eighth aspect of the present invention, there is provided a fuel cell power generation system, wherein the auxiliary device of the fuel cell main body is a fuel gas mixer. In a fuel gas mixer, fuel discharged as unreacted gas in a fuel cell reaction is mixed with a pre-reaction fuel gas supplied from the outside, and the unreacted gas has a high temperature about the operating temperature of the fuel cell. .
ADVANTAGE OF THE INVENTION According to this invention, the thickness of the heat insulation layer which suppresses the heat radiation from a fuel gas mixer can be made thin, and the volume of the said apparatus can be reduced. Furthermore, since the surface area of the heat insulating layer can be reduced, heat loss can be reduced, and the sensible heat of the unreacted gas can be efficiently given to the pre-reacted fuel gas.

A ninth invention provides a fuel cell power generation system, wherein the auxiliary device of the fuel cell main body is a heat exchanger. The heat exchanger is used to exchange heat between the high temperature exhaust gas of the fuel cell and the newly supplied fuel, air or other medium for utilizing heat. I have. ADVANTAGE OF THE INVENTION According to this invention, the thickness of the heat insulation layer which suppresses the heat radiation from a heat exchanger can be made thin, and the volume of the said apparatus can be reduced. Further, since the surface area of the heat insulating layer can be reduced, heat loss can be reduced, and the sensible heat of the high-temperature exhaust gas can be efficiently given to the medium to be subjected to heat exchange.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A fuel cell power generation system generally comprises a fuel cell main body and an auxiliary device for the fuel cell main body.

There are various types of fuel cells, such as a solid oxide fuel cell, a molten carbonate fuel cell, a phosphoric acid fuel cell, and a polymer electrolyte fuel cell.

Each fuel cell basically has an air electrode and a fuel electrode formed so as to face the electrolyte. Generally, air is supplied to the air electrode side as an oxidizing gas, and the fuel gas is supplied to the fuel electrode side. When a hydrogen gas or a hydrogen-rich gas is generally supplied, an electrochemical reaction occurs to generate electric power and heat. Depending on the type of the fuel cell, there is the above-mentioned optimum operating temperature, and if this operating temperature is not maintained, a predetermined power generation reaction is not performed and the power generation efficiency is reduced.

The fuel cell body referred to in the present invention comprises the fuel cell itself, equipment for supplying and exhausting an oxidant or fuel, and a heat insulating layer for maintaining an optimum temperature around the fuel cell. On the other hand, the auxiliary device of the fuel cell body referred to in the present invention includes a fuel gas processing device, a fuel gas mixer, a heat exchanger, a blower for a fuel gas, a blower for an oxidizing gas, and the like. For the auxiliary device, optimal specifications and optimal combinations are appropriately examined depending on the type of fuel cell, usage conditions, and the like. For example, a 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 ° C., and the operating temperature of the CO converter is about 350 ° C. Therefore, unless the operating temperature is maintained, a predetermined reforming reaction and a shift reaction are not performed, and a fuel gas having a predetermined composition cannot be generated. It is important to maintain an appropriate operating temperature for other heat exchangers and the like. For this reason, a heat insulating layer is provided around the auxiliary device of the fuel cell main body to maintain an optimum temperature.

Hereinafter, the present invention will be described more specifically with reference to the drawings. FIG. 1 is a configuration diagram of a fuel cell system showing one embodiment of the present invention. The fuel cell 1 is a solid oxide fuel cell having a bottomed cylindrical shape, and a plurality of fuel cells 1 are housed in a power generation reaction chamber 5. An exhaust air chamber 6 partitioned by a partition wall 7 is formed above the power generation reaction chamber 5, and a fuel gas chamber 4 is formed below the power generation reaction chamber 5. A heat insulating layer 10 is disposed around a fuel cell main body 16 including the power generation reaction chamber 5, the exhaust air chamber 6, and the fuel gas chamber 4.

Inside each fuel cell 1, an elongated air introduction pipe 2 for supplying air is inserted, and its lower end reaches near the bottom of the fuel cell 1. From the lower end of the air introduction pipe 2, air is supplied to the bottom of the fuel cell 1. The air supplied to the bottom of the fuel cell 1 goes upward inside the fuel cell 1 while contributing to the above-described power generation reaction, and is discharged as exhaust air through the exhaust air chamber 6. Outside the fuel cell 1, a fuel gas chamber 4
The fuel gas (H 2, CO, CH 4, etc.) is supplied upward from the fuel gas supply port 3. The fuel gas goes upward outside the fuel cell 1 while contributing to the above-described power generation reaction.

The fuel cell body 16 has an air supply blower 15, a fuel supply blower 13, a mixer 12 for mixing the supplied fuel and the exhausted fuel not consumed in the above reaction, a fuel processor 11, an exhausted air chamber. Ancillary devices such as a heat exchanger 14 utilizing the exhaust air exhausted from 6 are installed, and a heat insulating layer 10 is installed around the periphery as necessary.

At this time, the vacuum heat insulating layer 8 is provided on a part of the heat insulating layer 10. This vacuum heat insulating layer 8 has, for example, a heat conductivity of 1 / compared to a ceramic heat insulating material often used conventionally.
Since it is about 5, the internal heat is hardly transmitted as compared with the conventional product, and the surface temperature can be made the same as that of the conventional product even if the thickness is smaller than that of the conventional product. For this reason, the total thickness of the heat insulating layer 10 and the vacuum heat insulating layer 8 can be made thinner than the case where only the heat insulating layer 10 is used. Therefore, the total volume can be reduced, the installation floor area can be reduced, and the surface area can be reduced. Therefore, even if the surface temperature is the same, the amount of heat radiation can be reduced and the energy loss can be reduced.

In FIG. 1, it is installed on substantially the side of the power generation reaction chamber 5, but the same effect can be obtained by installing it on the upper or lower part. Further, even if the vacuum heat insulating layer 8 is provided on a part of the heat insulating layer 10 around the auxiliary device of the fuel cell main body, the surface temperature is maintained at the same level as when only the heat insulating layer 10 is used.
The total thickness of 0 and the vacuum heat insulating layer 8 can be reduced and the volume can be reduced, and the same effect as described above can be obtained.

[Brief description of the drawings]

FIG. 1 is a diagram schematically showing one embodiment of a fuel cell according to the present invention.

FIG. 2 is a diagram schematically showing one embodiment of a conventional fuel cell.

[Explanation of symbols]

 1: Cell 2: Air introduction pipe 3: Fuel gas supply port 4: Fuel gas chamber 5: Power generation reaction chamber 6: Exhaust air chamber 7: Partition wall 8: Vacuum heat insulating layer 9: Module container 10: Heat insulating material layer 16: Fuel cell Body

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5H026 AA04 AA05 AA06 CV02 CV03 CX10 5H027 AA04 AA05 AA06 BA01 BA17

Claims (9)

[Claims] 1. A fuel cell power generation system comprising: a fuel cell main body including equipment for supplying and exhausting fuel and the like to and from a fuel cell; and an auxiliary device for the fuel cell main body. A fuel cell power generation system having a heat insulating layer around the periphery and a vacuum heat insulating layer in at least a part of the heat insulating layer. 2. A fuel according to claim 1, wherein a vacuum heat insulating layer is provided on a heat insulating layer around a portion where the operating temperature is the highest and / or around the fuel cell body having the largest volume or an auxiliary device therefor. Battery power generation system. 3. The fuel cell power generation system according to claim 1, wherein at least a part of the vacuum heat insulating layer is cylindrical. 4. The fuel cell power generation system according to claim 1, wherein at least a part of the vacuum heat insulating layer is of a panel type. 5. The fuel cell power generation system according to claim 1, wherein at least a part of the vacuum heat insulating layer is of a jacket type. 6. The fuel cell power generation system according to claim 1, wherein the fuel cell body is a solid oxide fuel cell. 7. The fuel cell power generation system according to claim 1, wherein the auxiliary device of the fuel cell main body is a fuel gas processing device. 8. The fuel cell power generation system according to claim 1, wherein an auxiliary device of the fuel cell main body is a fuel gas mixer. 9. The fuel cell power generation system according to claim 1, wherein an auxiliary device of the fuel cell main body is a heat exchanger.