JP3433975B2 - High temperature solid electrolyte fuel cell - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high temperature solid electrolyte fuel cell for power generation using hydrocarbon fuel such as coal gasification gas fuel containing sulfur (S) content.

[0002]

2. Description of the Related Art Conventionally, a high temperature solid electrolyte fuel cell has been known in which hydrogen containing a sulfur (S) component such as hydrogen sulfide (H ₂ S) or a hydrocarbon fuel containing carbon monoxide as a main component is used as a fuel. There is. An example of this conventional fuel cell is shown in FIG. As shown in the figure, the high-temperature solid oxide fuel cell has a fuel electrode inside and an air electrode outside, and the fuel 12 introduced into the fuel supply chamber 11 flows through the fuel supply pipe 13. It is supplied to the solid electrolyte fuel cell stack 14 via the above.

The solid electrolyte fuel cell stack 14 is of a cylindrical type in which a plurality of fuel cells are connected in series. The solid electrolyte fuel cell stack 14 has a power generation chamber 15
A plurality of power generators are connected inside.

The fuel 12 supplied to the tip of the fuel solid electrolyte fuel cell stack 14 reacts in the solid electrolyte fuel cell, passes through the fuel discharge chamber 16, and then passes through the fuel discharge pipe 17 to the outside of the power generator. Is discharged. On the other hand, air 18 is supplied to the solid electrolyte fuel cell stack 14, and this air 18 is heated to 700 ° C. by a heat exchanger 19 that performs heat exchange with exhaust air and then supplied into the power generation chamber 15. Has been done. Oxygen in the air is consumed by the reaction of the solid oxide fuel cell, and the temperature of the power generation chamber rises from about 900 to 1000 ° C due to the heat generated by the reaction. Exhaust air is discharged to the outside of the power generator through the heat exchanger (regeneration heat exchanger) 19 via the air discharge pipe 20. Further, the entire power generation device is covered with the heat insulating material 21.

[0005]

By the way, in the conventional high temperature solid electrolyte fuel cell shown in FIG. 2, when the sulfur gas is contained in the coal gasification gas of the hydrocarbon fuel supplied inside, the fuel cell of the fuel cell There is a problem in that nickel, which is the fuel electrode, is poisoned to increase the overvoltage, and the cell output decreases as shown in FIG. In addition, the coal gasification gas generally contains 5
Since it contains about 0 ppm of sulfur component, there is a problem that it cannot be directly supplied to the solid electrolyte fuel cell as a fuel.

In view of the above problems, it is an object of the present invention to provide a high temperature solid electrolyte fuel cell that does not deteriorate in power generation characteristics even when a hydrocarbon fuel containing sulfur is used.

[0007]

The structure of a high temperature solid oxide fuel cell according to the present invention which achieves the above object, comprises a power generation chamber defined inside a container surrounded by a heat insulating material, and a fuel cell connected to the power generation chamber. Installed, connecting a plurality of solid oxide fuel cells in series,
A cylindrical solid electrolyte fuel cell stack having a closed lower end, a fuel supply chamber defined above the power generation chamber in the container, and partitioned between the power generation chamber and the fuel supply chamber, the solid A fuel discharge chamber having an upper end of the electrolyte fuel cell stack opened, a fuel supply pipe inserted into the stack while having one end opened to the fuel supply chamber and the other end opened inside the lower end of the stack, A high-temperature solid electrolyte fuel, which is installed in the container below the power generation chamber and includes an air heat exchanger that preheats air supplied to the power generation chamber, and uses a hydrocarbon fuel containing sulfur (S) as a fuel. In the battery, between the fuel supply header, which is installed above the fuel supply chamber and is composed of a catalyst-supporting porous plate filled with a desulfurization catalyst and having a plurality of pores, and between the power generation chamber and the fuel discharge chamber.
And provided between the fuel discharge chamber and the fuel supply chamber
The heat from the power generation chamber cut off, characterized by comprising a heat insulating means for maintaining a temperature necessary the temperature in the fuel supply header to the catalytic reaction of the desulfurization catalyst Te. In the above invention, the insulating means is the said power generating chamber retardant
The temperature inside the fuel supply header is adjusted to 320 to 400 ° C. by adjusting the thickness of the heat insulating material provided between the fuel discharge chamber and the fuel discharge chamber.
High temperature solid electrolyte fuel cell characterized by being maintained at the temperature of .

[0008]

In the above structure, the sulfur content in the fuel is desulfurized by the desulfurization catalyst filled in the fuel header before the fuel is supplied to the high temperature solid oxide fuel cell, so that the fuel electrode of the solid electrolyte fuel cell is poisoned. Battery output does not decrease. Further, by controlling the temperature in the fuel header, it is possible to maintain the temperature sufficient for the reaction of the desulfurization catalyst filled.

[0009]

EXAMPLE A preferred example of the high temperature solid oxide fuel cell according to the present invention will be described below.

FIG. 1 is a schematic view of a high temperature solid oxide fuel cell according to this embodiment, in which reference numeral 11 is a fuel supply chamber,
12 is fuel, 13 is fuel supply pipe, 14 is solid electrolyte fuel cell stack, 15 is power generation chamber, 16 is fuel discharge chamber, 17
Is a fuel exhaust pipe, 18 is air, 19 is a heat exchanger, 20 is an air exhaust pipe, and 21 is a heat insulating material.

In this embodiment, in the fuel supply chamber 11 for supplying the fuel 12, for example, a granular desulfurization catalyst 101 containing zinc oxide as a main component is placed on a catalyst supporting porous plate 103 having a plurality of pores 102. Is filled in.

Accordingly, the solid electrolyte fuel cell stack 14
The fuel 12 supplied to the tip of the is desulfurized by the desulfurization catalyst 101, reacted in the solid electrolyte fuel cell, and then discharged to the outside of the power generator through the fuel discharge chamber 16.

The desulfurization catalyst 101 to be charged becomes ZnS when it reacts with hydrogen sulfide and loses its desulfurization ability. Therefore, the amount of the catalyst to be charged is an amount capable of adsorbing the sulfur content contained in the coal gasification gas supplied for 40,000 hours of power generation time. Need to be filled.
Here, assuming that the coal gasification gas contains, for example, 50 ppm of hydrogen sulfide, the amount of S adsorbed during 40,000 hours is a solid with an output of 25 W operated at a current density of 200 mA / cm ^2. The weight of each electrolyte fuel cell stack 14 is 81 g. Adsorption capacity required to adsorb this 0.18g-S
/ G-ZnO desulfurization catalyst is 450 g. Further, when the solid electrolyte fuel cell stack 14 is mounted on the fuel supply header of 48 pieces with a diameter of 40 cm (output 1200 W), the catalyst specific gravity is about 1 g / cm ^3, so the catalyst may be filled to a thickness of 17 cm. It will be.

The solid electrolyte fuel cell is a power generation device that directly converts the chemical energy of the fuel into electricity. Energy that is not converted to electricity is converted to heat. Using the heat generated by this solid oxide fuel cell as a heat source, the internal temperature of the power generator is 90
It is kept at 0 to 1000 ° C. In the coal gasification gas supplied to the fuel supply chamber, sulfur components such as hydrogen sulfide contained in the fuel such as coal gasification gas are chemically fixed to the desulfurization catalyst by the reaction of the reaction formula shown in "Chemical formula 1" below. It

[0015]

Embedded image ZnO + H ₂ S → ZnS + H ₂ O

The desulfurization catalyst 101 has a temperature of 900.degree.
It is heated by the heat conduction from the power generation chamber 14 at 000 ° C. and the fuel 12 after being consumed in the solid electrolyte fuel cell stack 14. In this embodiment, the power generation chamber 15 and the fuel discharge chamber 1
At the inlet side of the fuel 12 in 6, the heat insulating materials 104 and 105 are respectively provided.
Is provided, and the fuel supply chamber 11 as a fuel header
The temperature of 320 to 400 ° C. necessary for the catalytic reaction of the desulfurization catalyst 101 filled inside is maintained.

That is, the desulfurization catalyst 101 is the fuel exhaust pipe 1.
7 is heated by the exhaust fuel flowing through 7 and the exhaust fuel in the fuel exhaust chamber 16, and the exhaust fuel in the fuel exhaust chamber 16 is also heated by the power generation chamber 14, so that the fuel is discharged between the fuel exhaust chamber 16 and the power generation chamber 14. By adjusting the thickness of the heat insulating material 104, the amount of heat from the power generation chamber 16 changes, and the temperature of the desulfurization catalyst 101 can be controlled.

The desulfurized fuel is supplied to the solid electrolyte fuel cell stack 14 through the fuel injection pipe 13. Since the sulfur content in the desulfurized fuel is 0.1 ppm or less, the power generation characteristics of the fuel cell will not be impaired.

[0019]

As described above with reference to the embodiments, the solid electrolyte fuel cell according to the present invention has the desulfurization catalyst arranged in the supply means. Therefore, even if a hydrocarbon fuel containing a sulfur component is used as the fuel. , The fuel electrode is not poisoned and the cell output does not decrease. Further, by adopting the heat control structure, it is possible to prevent deterioration of the catalytic ability of the desulfurization catalyst, and it is possible to perform stable power generation.

[Brief description of drawings]

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

FIG. 2 is a schematic view of a high temperature solid oxide fuel cell according to a conventional example.

FIG. 3 is a graph showing a power generation characteristic of a conventional technique.

[Explanation of symbols]

11 Fuel supply room 12 Fuel 13 Fuel supply pipe 14 Solid electrolyte fuel cell stack 15 power generation room 16 Fuel discharge chamber 17 Fuel discharge pipe 18 air 19 heat exchanger 20 Air exhaust pipe 21 thermal insulation 101 desulfurization catalyst 102 pores 103 catalyst supporting porous plate 104,105 thermal insulation

─────────────────────────────────────────────────── ─── Continuation of front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) H01M 8/04 H01M 8/12 H01M 8/24

Claims (2)

(57) [Claims] 1. A power generation chamber defined inside a container covered with a heat insulating material, and a plurality of solid electrolyte fuel cells vertically connected to the power generation chamber and connected in series to form a cylindrical shape with a closed lower end. A solid electrolyte fuel cell stack, a fuel supply chamber defined above the power generation chamber in the container, a partition between the power generation chamber and the fuel supply chamber, and an upper end of the solid electrolyte fuel cell stack. An opened fuel discharge chamber, a fuel supply pipe having one end opened to the fuel supply chamber and the other end opened to the inside of the lower end of the stack, and a fuel supply pipe inserted into the stack, and the power generation chamber in the container A high temperature solid electrolyte fuel cell, which is installed below and comprises an air heat exchanger that preheats air to be supplied to the power generation chamber, and uses a hydrocarbon fuel containing sulfur (S) as a fuel. Installed above the And between said fuel supply header composed of a catalyst supporting porous plate filled with cured catalyst having a plurality of pores, and the fuel discharge chamber and the power chamber
The fuel cell is provided between the fuel discharge chamber and the fuel supply chamber
Cuts off the heat from the power room and reduces the temperature in the fuel supply header.
High temperature, solid electrolyte fuel cell characterized by comprising a heat insulating means for maintaining the temperatures required for catalytic reaction of the desulfurization catalyst. 2. A high temperature solid electrolyte fuel according to claim 1.
In the battery, the insulating means is, between the fuel discharge chamber and the power chamber
By adjusting the thickness of the provided heat insulating material , the fuel supply
A high temperature solid electrolyte fuel cell, characterized in that the temperature inside the supply header is maintained at a temperature of 320 to 400 ° C.