JP2001283884A - Fuel cell generating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel cell generating device that prevents the trouble of reserved water flowing out totally from the steam separator at the time of the stoppage of the device and simplifies the blowdown circuit as well as reducing total cost. SOLUTION: The fuel cell generating device comprises a fuel cell body 1 which is mounted with a cooling plate flowing cooling water, a steam separator 5 separating the hot cooling water discharged from the cooling plate into steam and water and a generated water collector 7 for collecting the water generated in the fuel cell. The steam separator 5 is equipped with a blowdown circuit 100, which discharges the internal reserved water to the generated water collector 7. And the blowdown circuit is equipped with a blowdown water pressure control means having a thin pipe 10 of a smaller pipe sectional area than the main pipe of the circuit. A blowdown water drainage port 13 discharging into the generated water collector is installed at a higher position than a water level control position 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel cell cooling water system in a fuel cell power generator, and more particularly to a blow-down circuit provided in a steam separator.

[0002]

2. Description of the Related Art As is well known, a phosphoric acid type fuel cell applies a fuel gas (for example, hydrogen) and an oxidant gas (for example, air) as reaction gas to a fuel electrode and an oxidant electrode provided with an electrode catalyst layer. It is supplied continuously to electrochemically convert the energy of the fuel into electric energy.
FIG. 2 is a schematic diagram showing a basic configuration of a fuel gas supply system, an air supply system, and a cooling water system of a conventional fuel cell power generator using a phosphoric acid type water-cooled fuel cell.

The fuel cell main body 1 schematically shown is formed by stacking single cells formed by sandwiching an electrolyte layer holding phosphoric acid between a fuel electrode and an air electrode, and generating power for each of a plurality of layers. A cooling plate for removing the accompanying heat generation is provided. The raw fuel is desulfurized by the hydrodesulfurizer 4 to the fuel electrode of the fuel cell main body 1, mixed with steam by the ejector pump 3, and supplied to the fuel reformer 2.
The fuel gas having a high hydrogen concentration reformed by the above is supplied.

That is, the raw fuel is introduced into the hydrodesulfurizer 4 to add hydrogen, and the sulfur contained in the raw fuel as an odorant is adsorbed and removed, and then sent from the steam separator 5 in the ejector pump 3. Mixed with the steam to be recovered, and the fuel reformer 2
To generate a fuel gas having a high hydrogen concentration by a catalytic reaction and supply it to the fuel electrode. A pipe for supplying the fuel gas to the fuel electrode is connected to a recycle gas circuit for recirculating and mixing a part of the fuel gas with the raw fuel introduced into the hydrodesulfurizer 4. The hydrogen contained in the circulated fuel gas is configured to be effectively used for desulfurization in the hydrodesulfurizer 4.

The fuel electrode off-gas containing residual hydrogen discharged from the fuel electrode without contributing to the reaction and the combustion air supplied from the outside by a blower are introduced into the combustor of the fuel reformer 2 and burned. With this, the gas flowing through the fuel reformer 2 is heated. On the other hand, the reaction air is taken in and supplied to the air electrode of the fuel cell body 1 by a blower. The air electrode off-gas discharged from the air electrode contains reaction product water generated by the electrochemical reaction, and the combustion exhaust gas discharged from the combustor of the fuel reformer 2 is generated by combustion. Contains water produced by combustion. Therefore, the air electrode off-gas and the combustion exhaust gas are sent to the generated water recovery device 7, where the generated water is recovered and then discharged to the outside.

A steam separator 5 is provided on the cooling plate of the fuel cell body.
More cooling water is supplied to remove heat generated by power generation, and the temperature of the fuel cell main body is maintained at a predetermined operating temperature. The cooling water, which has been heated to a high temperature by receiving heat from the cooling plate, is cooled by the cooling water cooler 6 and then returned to the steam separator 5 to be separated into steam and water. Note that heat obtained by cooling the cooling water cooler 6 is taken out to the outside and is effectively used. The steam separated by the steam separator 5 is sent to the ejector pump 3 and used for reforming as described above. Further, in order to compensate for the amount of water reduced by supplying steam to the ejector pump 3, the generated water recovery device 7
The product water collected in the above is purified by a water treatment device 8 and introduced.

Further, the steam separator 5 is provided with a blowdown circuit 100 for blowing down the stored water and sending it to the generated water recovery device 7. 7 and water treatment equipment 8
By returning the water to the steam separator 5, the water quality of the stored water is prevented from lowering.

As shown in FIG. 2, the blow-down circuit 100 includes a thin tube 1 as blow-down water pressure adjusting means.
0, an electromagnetic shutoff valve 11 and a manual valve 9. This blow-down circuit ensures that a flow of water at a flow rate corresponding to the load always flows during operation, and at the time of a normal or emergency stop of the apparatus, a predetermined water level control position 12 corresponding to a predetermined water storage amount prepared for re-operation. , The electromagnetic shut-off valve 1
1 is shut off to protect all the water stored in the steam separator 5 from flowing out. The manual valve 9 is used for shutting off a circuit at the time of an airtight test.

By the way, the configuration using the thin tube 10 as the blow-down water pressure adjusting means as described above has been proposed by the applicant of the present application in order to solve the problem of the flow rate decrease caused by the flushing of water when using a fixed throttle. JP-A-11-8688
This is the configuration proposed in Japanese Patent Application Publication No. 9-99. The thin tube 1
The inner diameter of 0 is preferably 3 mm or less in consideration of the pressure drop from the pressure (normally about 0.6 MPaG) during operation of the steam separator 5 to the product water recovery device 7 (atmospheric pressure).

[0010]

As described above, in the conventional fuel cell power generator, the electromagnetic shutoff valve 11 is shut off to protect all the water stored in the steam separator 5 from flowing out. However, there were the following problems.

When foreign matter such as minute dust and silica-forming substances contained in the blow-down water accumulates and adheres to the electromagnetic shut-off valve 11 when the apparatus is stopped, the blow-down water flows out to a predetermined level. The water level gradually drops from the water level control position of
Eventually, there is a problem that all the stored water in the steam separator 5 flows out. In this case, it is necessary to re-inject the water of the cooling water system including the steam separator 5 and the fuel cell body 1 at the time of restart, and there is a problem that it takes time to restart.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to prevent a trouble that all the water stored in a steam separator flows out when the apparatus is stopped, and to simplify a blowdown circuit. SUMMARY OF THE INVENTION It is an object of the present invention to provide a fuel cell power generation device that aims to reduce the total cost.

[0013]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a fuel cell main body having a cooling plate through which cooling water flows, and supplying cooling water to the cooling plate. A steam separator for introducing high-temperature cooling water discharged from the cooling plate to separate into steam and water, and a product water recovery device for recovering product water in the fuel cell; The blower has a blowdown circuit for discharging the stored water to the generated water recovery unit, and this blowdown circuit adjusts the blowdown water pressure using a small tube with a smaller cross-sectional area than the main piping of the circuit. In the fuel cell power generation apparatus provided with the means, the blowdown water discharge port discharged to the generated water recovery unit is provided at a position higher than a water level control position in the steam separator (claim 1).

In the above configuration, as will be described in detail later, the electromagnetic shut-off valve of the blow-down circuit can be omitted. For this reason, there is no trouble that all the water stored in the steam separator flows out when the apparatus is stopped due to the foreign matter deposited on the electromagnetic shut-off valve, and the reliability of the apparatus can be improved. Also, because there is no solenoid shut-off valve, the blowdown circuit is simplified,
It is possible to reduce costs in terms of direct material costs and software production.

Further, in the fuel cell power generator according to claim 1, the blowdown water pressure adjusting means is provided at a position higher than the water level control position (claim 2).
It is preferable that

As described above, when the apparatus is stopped, the water inside the thin tube as the blowdown water pressure adjusting means is discharged, so that the problem that the scale contained in the water stays and accumulates and the water flow gradually deteriorates is prevented. can do.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. In the embodiment shown in FIG. 1, members having the same functions as those shown in FIG. 2 are denoted by the same reference numerals, and description thereof is omitted.

The embodiment of FIG. 1 is different from that of FIG. 2 in that a discharge port 13 for discharging the stored water in the steam separator 5 to a generated water recovery unit 7 is provided at a water level control position 12 of the steam separator 5. In order to make the position higher than that, the rising pipe 14 is provided at the subsequent stage of the thin tube 10 in the blowdown circuit 100, and the electromagnetic shutoff valve 11 in FIG.
In FIG. 1, the thin tube 10 is shown at a position lower than the water level control position, but it can be provided at a higher position if necessary, which is more preferable as described above. In this case, the pipe at the subsequent stage of the thin tube 10 may be piped downward and connected to the generated water recovery unit 7 in some cases.

In the above configuration, if the water pressure is about 0.6 MPaG at the outlet of the steam separator 5 and about 0.2 MPaG at the outlet of the capillary 10 during normal operation, the pipe at the subsequent stage of the capillary 10 is connected to the steam separator 5. Even if the blowdown water is introduced above the water level control position 12 and the blowdown water is introduced into the generated water recovery unit 7, the blowdown can be sufficiently performed.

On the other hand, when the apparatus is stopped, the pressure in the steam separator 5 and the blow-down circuit system gradually decreases to atmospheric pressure. The water flow stops in a state where the position coincides with the position, the water seal state is established, and blowdown water does not flow to the generated water recovery unit 7. Therefore, even if the electromagnetic shut-off valve 11 is not provided unlike the conventional apparatus, the apparatus can be stopped stably with high reliability.

[0021]

As described above, according to the present invention, the fuel cell main body having the cooling plate through which the cooling water flows, the cooling water supplied to the cooling plate, and discharged from the cooling plate. A steam separator for introducing high-temperature cooling water to separate into steam and water, and a product water recovery device for recovering product water in the fuel cell, and wherein the steam separator has an internal storage water. A blowdown circuit for discharging water to a generated water recovery unit, the blowdown circuit comprising a blowdown water pressure adjusting means using a narrow pipe having a smaller pipe cross-sectional area than a main pipe of the circuit. In the apparatus, the blowdown water discharge port for discharging to the generated water recovery unit is provided at a position higher than the water level control position in the steam separator, so that all the water stored in the steam separator flows out when the apparatus is stopped. Do To prevent trouble, blow - thereby promoting simplification of the down circuit, it is possible to reduce the total cost.

[Brief description of the drawings]

FIG. 1 is a system diagram of a fuel cell power generator according to an embodiment of the present invention.

FIG. 2 is a system diagram of a conventional fuel cell power generator.

[Explanation of symbols]

1: fuel cell main body, 2: fuel reformer, 5: steam separator, 7: produced water collector, 8: water treatment device, 10: thin tube,
12: water level control position, 13: discharge port, 100: blowdown circuit.

Claims (2)

[Claims] 1. A fuel cell main body including a cooling plate through which cooling water flows, supplying cooling water to the cooling plate, and introducing high-temperature cooling water discharged from the cooling plate to form steam. A steam separator for separating water and a generated water collector for collecting generated water in the fuel cell, and the steam separator is for discharging stored water inside to the generated water collector. A blow-down circuit is provided.
In a fuel cell power generation apparatus provided with a blowdown water pressure adjusting means using a small tube having a smaller pipe cross-sectional area than a main pipe of a circuit, a blowdown water discharge port for discharging to the generated water recovery unit is provided with the steam separator. A fuel cell power generator provided at a position higher than the water level control position in (1). 2. The fuel cell power generator according to claim 1, wherein said blowdown water pressure adjusting means is provided at a position higher than said water level control position.