JPH06196192A - Solid electrolyte type fuel cell - Google Patents

Abstract

PURPOSE:To uniformize a temperature in a reaction chamber by supplying air flowing outside of a cell tube from the upper end part side of an air supply pipe, and flowing it to the lower part side from the reaction chamber upper part side. CONSTITUTION:Air 2 supplied from an air inlet pipe 12 in a lower part of a module is supplied to a reaction chamber 7 after passing through an air preheater 4 and also passing through an air supply pipe 22 arranged in the central part of the reaction chamber 7. A ceramics foaming body 6 to promote heat transfer to the air 2 from inside of the reaction chamber 7, is filled in the air supply pipe 22. The air coming out from an upper end opening part of the air supply pipe flows to the lower part side from the upper part side of the reaction chamber 7, and passes through the air preheater 4, and is discharged outside of the module after being used for power generation. Thereby, fuel gas 10 flowing to above from below in a cell tube 1 and the heated air flowing below from above outside of it flow oppositely to each other, and as for the supplied air, heat can be absorbed efficiently in the air from the whole reaction chamber, so that a temperature in the reaction chamber can be uniformized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solid oxide fuel cell, and more particularly to a uniform temperature in a reaction chamber.

[0002]

2. Description of the Related Art FIG. 2 schematically shows a conventional solid oxide fuel cell. In FIG. 2, 1 is a cell tube,
2 is air, 3 is exhaust air, 4 is air preheater, 5 is air exhaust pipe, 6 is ceramic foam, 7 is reaction chamber, 8 is fuel header, 9 is heat insulating material, 10 is fuel gas, 11 is fuel supply A tube, 12 is an air inlet tube, and 13 is an air outlet tube.

The air preheating method in the conventional module will be described with reference to FIG. 2. First, the air 2 introduced from the air inlet pipe 12 is preheated to about 700 ° C. by the air preheater 4, and then the reaction is performed. The surface of the ceramic foam 6 interposed at the inlet of the chamber 7 absorbs heat in the reaction chamber 7, and is further preheated to 900 ° C. and heated air is supplied into the reaction chamber 7.

Further, after being raised in the reaction chamber 7 and consumed for power generation, the exhaust air 3 passes through an air exhaust pipe 5 made of, for example, Al ₂ O ₃ , and then passes through an air preheater 4 and then air. It is discharged from the outlet pipe 13 to the outside of the module.

On the other hand, the fuel gas 10 is the fuel gas header 8
Therefore, the fuel is supplied into the cell tube 1 through the fuel supply pipe 11. After that, it is used for power generation while rising in the cell tube 1, and then discharged to the outside of the module through the fuel header 8.

[0006]

By the way, in the prior art, the fuel gas 10 in the cell tube 1 used for power generation and the heated air 2 flowing outside thereof flow in the same direction.

At this time, heat is generated in the cell tube 1 during power generation by the amount of voltage drop due to the internal resistance of the cell (see "Equation 1" below).

[0008]

## EQU1 ## Q = I.ΔE = I ² R Here, Q is the power generation amount, I is the current, ΔE is the voltage drop, and R is the cell internal resistance.

Since this reaction proceeds from the lower side of the cell tube 1 to the upper side (from the inlet side to the outlet side), the temperature near the upper portion (outlet side) of the cell tube 1 tends to rise.

Since the air 1 also absorbs heat while rising due to the reaction heat of the cell tube 1, the temperature of the upper part of the reaction chamber 7 rises. On the other hand, since the ceramic foam 6 absorbs the amount of heat in the lower portion of the reaction chamber 7, the lower temperature of the reaction chamber 7 tends to decrease.

Therefore, there is a problem that the temperature inside the reaction chamber 7 is generally low on the lower side and high on the upper side. Therefore, there is a problem that the air flow rate is increased in order to positively suppress the temperature rise in the reaction chamber, which requires auxiliary machine power, resulting in poor power generation efficiency.

In view of the above problems, it is an object of the present invention to provide a solid oxide fuel cell in which the temperature inside the reaction chamber is made uniform.

[0013]

In order to achieve the above object, a solid oxide fuel cell according to the present invention has a structure in which a module is surrounded by a heat insulating material, and a fuel header arranged in an upper part of the inside and a fuel header A reaction chamber having a reaction chamber lower portion provided on the lower side of the header, an air preheater formed on the lower side of the reaction chamber, and a fuel supply pipe disposed inside the reaction chamber suspended from the fuel header. In a solid oxide fuel cell including a bottomed cell tube, an upper end opening is provided in the vicinity of the lower surface of the fuel header, and an air supply pipe for passing supply air from below to above is provided in the reaction chamber. In addition, the fuel gas flowing inside the cell tube flows downward from above, and the air flowing outside the cell tube flows downward from above.

[0014]

In the above structure, the fuel gas flowing in the many cell tubes suspended in the reaction chamber is caused to flow from the lower side to the upper side, and the air flowing outside the cell tubes is supplied from the upper end side of the air supply pipe. , Flow from the upper side of the reaction chamber to the lower side to achieve uniform heating in the reaction chamber.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the solid oxide fuel cell of the present invention will be described below with reference to the drawings.

As shown in the figure, in the solid oxide fuel cell module, a reaction chamber is provided between a fuel header 8 having an inner upper portion surrounded by a heat insulating material 9 and a reaction chamber lower portion 21 provided therebelow. 7 and is provided with an air preheater 4 on the lower side thereof.

In the reaction chamber 7, a large number of cylindrical bottomed cell tubes 1 are attached to a fuel header 8 and arranged therein. A fuel supply pipe 10 is inserted into the inside of the fuel header 8, and a fuel not shown is shown. Fuel is supplied from the supply unit into the fuel supply pipe 10.

An air supply pipe 22 having a skirt-shaped open end for introducing air and having a ceramic foam 6 filled therein is disposed above the air preheater 4. The upper end of the air supply pipe 22 is open and reaches the vicinity of the upper part of the lower surface of the reaction chamber 7.

Further, an air inlet pipe 12 and an air outlet pipe 13 are connected below the module. In the air preheater 4, since the air supply passage and the air discharge passage form separate passages, the passage of the exhaust air 3 and the air 2 are formed.
The heat exchange is performed without being mixed with the flow channel of. still,
Exhaust air 3 that has not been used for power generation in the reaction chamber 7 flows in from the lateral direction of the air preheater 4 and is discharged from the air outlet pipe 13 below.

In the above structure, the air 2 supplied from the air inlet pipe 12 at the lower part of the module passes through the air preheater 4 and further the air supply pipe 22 arranged in the central portion of the reaction chamber 7.
After passing through, it is supplied into the reaction chamber 7. At this time, in this embodiment, the air supply pipe 22 is filled with the ceramic foam 6 in order to promote heat transfer from the inside of the reaction chamber 7 to the air 2. The ceramic foam 6 is not necessarily filled, but it is preferable to fill it because the temperature in the reaction chamber 4 becomes uniform.

The air 2 discharged from the upper end opening of the air supply pipe 22 filled with the ceramic foam 6 flows from the upper side to the lower side of the reaction chamber 4, is used for power generation, and then flows through the air preheater 4. And discharged to the outside of the module. As the material of the air supply pipe 22, for example, a quartz pipe or a material having a high thermal conductivity (for example, a metal) is used in order to efficiently transfer the heat (radiation heat, conduction heat) of the reaction chamber 7 to the filled ceramic foam body 6. Good if not.

Therefore, the fuel gas 10 flowing from the lower side to the upper side in the cell tube 1 and the heated air flowing from the outer side to the lower side from the upper side flow opposite to each other, and the supplied air 2 is supplied. Since heat can be efficiently absorbed into the air from the entire reaction chamber 7, the temperature inside the reaction chamber 7 can be made uniform. When the temperature of the lower part of the reaction chamber 7 drops, the ceramic foam 6 is also placed in the lower part 21 of the reaction chamber so that the radiant heat in the lower part of the reaction chamber 21 escapes downward. May be blocked.

[0023]

As described above with reference to the embodiments, according to the present invention, air is supplied to the vicinity of the upper portion of the reaction chamber while being heated, and thereafter, the lower side of the reaction chamber is placed so as to face the fuel gas in the cell tube. The temperature inside the reaction chamber can be made uniform because it flows into the chamber. Further, when the module has a large capacity, it is necessary to have a plurality of air supply pipes for uniform distribution of air. In such a case, the heat inside the reaction chamber can be efficiently absorbed and the reaction chamber can be efficiently absorbed. The internal temperature rise can also be suppressed. Therefore, in order to suppress the temperature rise in the reaction chamber, it is necessary to actively cool the air to increase the air flow rate. However, with the structure of the present invention, the air flow rate can be reduced, and the auxiliary machine power can be reduced accordingly. .

[Brief description of drawings]

FIG. 1 is a schematic view of a solid oxide fuel cell according to this embodiment.

FIG. 2 is a schematic diagram of a solid oxide fuel cell according to a conventional technique.

[Explanation of symbols]

 1 Cell Tube 2 Air 3 Exhaust Air 4 Air Preheater 5 Air Discharge Pipe 6 Ceramic Foam 7 Reaction Chamber 8 Fuel Header 9 Insulation Material 10 Fuel Gas 11 Fuel Supply Pipe 12 Air Inlet Pipe 13 Air Outlet Pipe 21 Lower Reaction Chamber 22 Air Supply pipe

Claims (2)

[Claims] 1. A fuel header having a module surrounded by a heat insulating material and disposed in an upper part of the inside, and a reaction chamber having a reaction chamber lower part provided below the fuel header.
A solid oxide fuel cell comprising an air preheater formed on the lower side of the reaction chamber and a bottomed cell tube suspended from the fuel header into the reaction chamber and provided with a fuel supply pipe inside, The fuel header has an upper end opening near the lower surface, and an air supply pipe, which allows the supply air to pass from the lower side to the upper side, is provided in the reaction chamber. The fuel gas flowing in the cell tube is directed from the lower side to the upper side. A solid oxide fuel cell, wherein the air flowing outside the cell tube is caused to flow downward from above. 2. The solid oxide fuel cell according to claim 1, wherein the air supply pipe is filled with a ceramic foam.