JPH09167624A - Power generation device of solid electrolyte fuel cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To maintain long-hour recycling operation, and effectively use fuel by detecting the concentration of unreactive fuel in a recycling pipe, and controlling two opening-closing means so as to be opened and closed on the basis of this concentration. SOLUTION: A recycling pipe 17 is connected to a compressor 14. This pipe 17 branches off, and one leads to a chimney 19 through a recycling bypass valve 15, and the other leads to a flowmeter 18 and a hydrogen concentration meter 23 through a delivery valve 16 of the compressor. The meter 23 is a concentration detecting means to detect unreactive fuel. The recycling pipe 17 recycles the compressed unreactive fuel to a solid electrolyte fuel cell, and two opening-closing means 24 and 25 are arranged in the recycling pipe 17 and a recycling discharging line 26, and respectively open and close passages of the recycling pipe 17 and the line 26. Therefore, supply of the unreactive fuel to a fuel cell can be stopped simultaneously when the concentration of the compressed unreactive fuel reaches a prescribed value. Then, deflagation of the fuel cell 1 caused by the concentration can be checked, and safety can be enhanced.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a power generator for a solid oxide fuel cell.

[0002]

2. Description of the Related Art FIG. 2 is a solid oxide fuel cell module (hereinafter referred to as SOFC module) in a conventional power generating apparatus of this type. SOFC: Solid Oxide F
(cellCell) is a system diagram during a recycling operation.
In FIG. 2, 1 is an SOFC module, and the inside of this module 1 is maintained at a temperature of 900 ° C to 1000 ° C. In the module 1, the fuel 29 such as hydrogen supplied by the fuel supply pipe 2 and the oxygen (air) 31 supplied by the air supply pipe 3 react with each other to generate the fuel 2 such as hydrogen.
The energy of 9 is directly converted into electricity to generate electricity.

On the other hand, an air-fuel mixture of unreacted fuel such as hydrogen that is not used for power generation and steam generated by power generation passes through the fuel discharge pipe 4 and is separated in the drain pot 9 into steam, which is eventually discharged from the chimney 19 to the atmosphere. . Further, the water vapor separated in the drain pot 9 is discharged from the drain discharge valve 10 to the outside of the system as drain. On the other hand, unreacted oxygen (air) that is not used for power generation passes through the air discharge pipe 20 and is released from the chimney 22 to the atmosphere.

Further, in order to prevent air from leaking from the air electrode side to the fuel electrode side of the solid electrolyte fuel cell (hereinafter referred to as SOFC) in the module 1, the air flow from the fuel electrode side to the air electrode side shown in the figure is prevented. The pressure ΔP is controlled by the pressure regulating valve 5, the bypass valve 7 installed in the bypass line 6, the air discharge valve 21 and the like so that the pressure ΔP becomes about 50 mmAg.

Usually, about 60% of the fuel such as hydrogen is used for the reaction, and about 40% of the remaining fuel is discarded. Therefore, in order to effectively use the fuel, unreacted fuel such as hydrogen in the fuel discharge pipe 4 is sucked by the compressor 14 or the like and recycle-supplied to the fuel supply pipe 2 connected to the module 1. .

The operation method system in this case will be described with reference to FIG. First, the fuel discharge valve 12 and the recycle bypass valve 15 are closed, and the compressor suction valve 13 and the compressor discharge valve 1 are closed.
Open 6 Then, the compressor 14 is operated, and a specified amount of fuel such as unreacted hydrogen measured by the flow meter 18 is supplied from the recycle pipe 17 to the fuel electrode side of the module 1.

[0007]

SOF as described above
There are the following problems during the C module recycling operation. When the flange 8, 11, the fuel discharge valve 12, the compressor suction valve 13 or the suction side seal surface of the compressor 14 installed in the upstream pipe of the compressor 14 deteriorates and the airtightness cannot be maintained, the suction of the compressor 14 Since the inside of the side pipe has a negative pressure, air is sucked from each seal surface by the compressor 14, and a mixture of air and fuel such as hydrogen is supplied to the module 1. The temperature inside the module 1 is 900 ° C to 100 ° C.
Since the temperature is ℃, the hydrogen concentration in the mixture is 4 to 75 Vo.
When it reaches the range of 1%, this becomes an ignition source and deflagrates in the module 1 and the SOFC is destroyed.

An object of the present invention is to provide a power generator of a solid electrolyte fuel cell capable of maintaining a recycling operation for a long time, effectively utilizing fuel, and capable of operation for power generation by a highly safe solid electrolyte fuel cell. To do.

[0009]

In order to solve the above-mentioned problems and achieve the object, the solid oxide fuel cell power generator of the present invention is constructed as follows. The power generator of the solid electrolyte fuel cell of the present invention is a power generator of the solid electrolyte fuel cell that reacts fuel and air at high temperature to generate power, and in order to recycle compressed unreacted fuel to the solid electrolyte fuel cell. A recycle pipe, a concentration detection means for detecting the concentration of the unreacted fuel in the recycle pipe, and a recycle release line branched from the recycle pipe,
Two opening / closing means provided respectively on the recycling pipe and the recycling discharge line for opening / closing the flow paths in the recycling pipe and the recycling discharge line, respectively, and the two opening / closing means based on the concentration detected by the concentration detecting means. And a control means for controlling opening / closing of the opening / closing means.

[0010] As a result of taking the above measures, the following effects are produced. According to the power generator of the solid oxide fuel cell of the present invention, since the opening / closing means for opening / closing the recycle pipe and the flow path in the recycle release line is controlled based on the concentration of unreacted fuel, it is compressed. The supply of the unreacted fuel to the solid oxide fuel cell can be stopped at the same time when the concentration of the unreacted fuel reaches a predetermined value. As a result, it is possible to maintain the recycling operation for a long time, effectively use the fuel, and prevent deflagration of the solid electrolyte fuel cell due to the concentration of the unreacted fuel, and the solid electrolyte fuel cell having high safety. The operation for power generation is enabled.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a system diagram of a SOFC module in a solid oxide fuel cell power generator according to an embodiment of the present invention during a recycling operation. In FIG. 1, the same parts as those in FIG. 2 are designated by the same reference numerals.

In FIG. 1, reference numeral 1 is an SOFC module, and a fuel supply pipe 2, an air supply pipe 3 and air exhaust pipes 4 and 20 are connected to the SOFC module 1.
The air discharge pipe 4 communicates with the inside of the drain pot 9 via the pressure regulating valve 5 and the flange 8. Further, a pipe 27 communicates with the flange 11 from the inside of the drain pot 9, and further branches from the flange 11, one of which communicates with the chimney 19 through the fuel discharge valve 12 and the other of which communicates with the compressor suction valve 13 To the compressor 14 via. Further, the drain pot 9 is provided with a drain discharge valve 10. A bypass line 6 is connected to the air discharge pipe 4 at a location where the pressure regulating valve 5 is provided, and the bypass line 6 is provided with a bypass valve 7.

A recycle pipe 17 is connected to the compressor 14. The recycle pipe 17 is branched, one of which is connected to the chimney 19 through the recycle bypass valve 15 and the other of which is the compressor discharge valve 16 To the flowmeter 18 and the hydrogen concentration meter 23. Further, the recycle pipe 17 is branched at the outlet of the flowmeter 18, and one of them is connected to the SOFC module 1 via the shutoff valve 24 and the pipe 28.
The other end is connected to the chimney 19 by a recycle discharge line 26 via a shutoff valve 25.

The hydrogen concentration meter 23 includes shutoff valves 24 and 25.
Is installed so as to measure the hydrogen concentration in the recycling pipe 17 at the location where is provided. Also, SOF
The air discharge pipe 20 connected to the C module 1 communicates with a chimney 22 via an air discharge valve 21.

Unlike FIG. 2, in FIG. 1, the recycle pipe 17 at the outlet of the compressor 14 is branched and the hydrogen concentration in the recycle pipe 17 is constantly measured by the hydrogen concentration meter 23. In addition, the recycling pipe 1 branched at the outlet of the flow meter 18
The shut-off valve 24 is installed on one side of the No. 7 and the recycle discharge line 26 is provided on the other side, and the shut-off valve 25 is installed on the discharge line 26. Further, the output side of the hydrogen concentration meter 23 is connected to the shutoff valves 24 and 25, and when the hydrogen concentration in the recycle pipe 17 reaches 80%, the shutoff valve 24 is closed,
The unreacted hydrogen to the fuel electrode side of the SOFC module 1 is shut off, the shutoff valve 25 is opened, and the unreacted hydrogen is released to the chimney 19 through the recycle release line 26.

As described above, the hydrogen concentration in the recycle pipe 17 at the outlet of the compressor 14 is constantly measured by the hydrogen concentration meter 23. The output side of the hydrogen concentration meter 23 is connected to the shutoff valves 24 and 25, and the shutoff valves 24 and 25 operate in reverse. That is, when the shutoff valve 24 is open, the shutoff valve 25 is closed, and when the shutoff valve 24 is closed, the shutoff valve 25 is open. When the fuel 29 is hydrogen, the explosion range for air is 4 to 75 Vol%.

When there is no leak from the above-mentioned sealing surface, the hydrogen concentration in the recycle pipe 17 is 100%.
However, when a leak occurs, the hydrogen concentration in the recycling pipe 17 decreases. Here, since the upper limit value of the explosion range of hydrogen is 75%, allowance is added to this, and the shutoff valve 24 is closed and the shutoff valve 25 is opened when the hydrogen concentration meter 23 indicates 80%. Not controlled by control means. As a result, the supply of unreacted hydrogen to the fuel electrode side of the SOFC module 1 can be cut off,
It is possible to prevent deflagration in the module 1 and prevent SOFC from being destroyed.

The present invention is not limited to the above-mentioned embodiment, and can be carried out by appropriately modifying it without departing from the scope of the invention. (Summary of Embodiment) The configuration, operation and effect shown in the embodiment are summarized as follows.

The solid oxide fuel cell power generator shown in the embodiment is compressed in the solid oxide fuel cell (1) power generator for generating electricity by reacting the fuel (29) and air (31) at a high temperature. A recycling pipe (17) for recycling the unreacted fuel to the solid electrolyte fuel cell (1), and a concentration detecting means (23) for detecting the concentration of the unreacted fuel in the recycling pipe (17). And a recycling discharge line (26) branched from the recycling pipe (17), the recycling pipe (17) and the recycling discharge line (26) respectively, and the recycling pipe (17) and the recycling discharge line, respectively. (2
Two opening and closing means (2) for opening and closing the flow path in 6)
4, 25) and control means for controlling the opening / closing of the two opening / closing means (24, 25) based on the concentration detected by the concentration detecting means (23).

As described above, in the solid oxide fuel cell power generator, the two opening / closing means (24, 25) for opening / closing the flow paths in the recycle pipe (17) and the recycle discharge line (26) are not provided. Since the opening / closing control is performed based on the concentration of the reacted fuel, the supply of the unreacted fuel to the solid electrolyte fuel cell (1) can be stopped at the same time when the concentration of the compressed unreacted fuel reaches a predetermined value. it can. As a result, it is possible to maintain the recycling operation for a long time, to effectively use the fuel, and to prevent deflagration of the solid electrolyte fuel cell (1) due to the concentration of the unreacted fuel. Operation for power generation by the electrolyte fuel cell (1) becomes possible.

[0021]

EFFECTS OF THE INVENTION According to the present invention, a solid oxide fuel cell power generator capable of maintaining a long-term recycling operation, effectively utilizing fuel, and capable of operation for power generation by a highly safe solid oxide fuel cell. Can be provided.

[Brief description of the drawings]

FIG. 1 is a system diagram during a recycling operation of an SOFC module in a solid oxide fuel cell power generator according to an embodiment of the present invention.

FIG. 2 is a system diagram of a SOFC module in a conventional solid oxide fuel cell power generator during a recycling operation.

[Explanation of symbols]

 1 ... SOFC module 2 ... Fuel supply pipe 29 ... Fuel such as hydrogen 3 ... Air supply pipe 31 ... Oxygen (air) 4 ... Air discharge pipe 5 ... Pressure adjusting valve 6 ... Bypass line 7 ... Bypass valve 8 ... Flange 9 ... Drain Pot 10 ... Drain discharge valve 11 ... Flange 12 ... Fuel discharge valve 13 ... Compressor suction valve 14 ... Compressor 15 ... Recycle bypass valve 16 ... Compressor discharge valve 17 ... Recycle pipe 18 ... Flowmeter 19 ... Chimney 20 ... Air discharge Pipe 21 ... Air discharge valve 22 ... Chimney 23 ... Hydrogen concentration meter 24 ... Shutoff valve 25 ... Shutoff valve 26 ... Recycle discharge line 27 ... Piping 28 ... Piping

Claims (1)

[Claims] 1. A power generation device for a solid electrolyte fuel cell for reacting fuel and air at high temperature to generate electricity, and a recycle pipe for recycling compressed unreacted fuel to the solid electrolyte fuel cell. Concentration detecting means for detecting the concentration of the unreacted fuel inside, a recycle release line branched from the recycle pipe, the recycle pipe and the recycle release line, respectively, the recycle pipe and the recycle release line, respectively. Solid electrolyte fuel, characterized by comprising: two opening / closing means for opening / closing the flow path in the above; and a control means for controlling the opening / closing of the two opening / closing means based on the concentration detected by the concentration detecting means. Battery power generator.