JPH0963611A - Water-cooled fuel cell power generating apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a water-cooled fuel cell power generating apparatus in which microbe propagation can be prevented without requiring complicated maintenance work such as washing of a produced water recovering system and a water treating system with chemicals. SOLUTION: A fuel cell 1 consisting of layered bodies of a plurality of unit cells and cooling plates 3 is provided with a cooling water circulating system 10 to circulate cooling water 6 to cooling pipes in the cooling plates, a produced water recovering system 20 which condenses steam in waste gases 7, 8 of the fuel cell and a fuel reforming apparatus 2 to recover as water, mixes the water with tap water to give mixed water 26, and store the mixed water 26, and a water treating system 30 which converts the mixed water into pure water 26P and supplies to the cooling water circulating system 10. As an antibacterial filter 40 to inhibit propagation of microbes in the mixed water 26, tanks 41, 42 filled with granular adsorbents bearing antibacterial metal films on the surface are installed in an upper stream side of a mixed water circulating system 25 in the produced water recovering system or of an ion-exchange type pure water producing apparatus 31 in the water treating system 30.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water-cooled fuel cell power generator equipped with a cooling water circulation system and a cooling water replenishing device, and more particularly to a water cooling fuel cell power generator having a cooling water replenishing device preventing bacterial growth. .

[0002]

2. Description of the Related Art FIG. 2 is a block diagram showing a main part of a conventional water-cooled fuel cell power generator. In a phosphoric acid fuel cell 1, a fuel electrode and an air electrode are arranged with a matrix holding phosphoric acid interposed therebetween. It is composed of a stack of unit cells, and the fuel gas 2F generated by the fuel reforming device 2 is supplied to the fuel electrode and the air is supplied to the air electrode, so that power generation is performed based on the electrochemical reaction. Moreover, the electrochemical reaction of the fuel cell 1 is an exothermic reaction as a whole, and the temperature of the fuel cell 1 is
The fuel cell must be cooled in order to perform efficient power generation operation while maintaining the operating temperature at about 90 ° C. Therefore,
A cooling plate 3 having pure water as cooling water 6 is laminated on the fuel cell 1. In order to circulate the cooling water 6 through the cooling plate 3, a water vapor separator 11 and a circulation pump 12 and, if necessary, are provided. A cooling water circulation system 10 including a heat exchanger for cooling (not shown) and the like is connected.

In order to reform a raw fuel into a hydrogen-rich fuel gas, a fuel reformer for adding a reforming steam to methane gas or the like as a raw fuel to promote a reaction between water and methane with a catalyst. 2 is used, and a part of the steam separated by the steam separator 12 is used for the reforming steam. Therefore, it is necessary to supply the pure water 6P to the cooling water circulation system 10 in accordance with the amount of steam used for reforming the fuel. For this pure water 6P, ion-exchanged water from which impurities have been removed in a water treatment system 30 including an ion-exchange type pure water device 31 and a pump 32 is used. In the air-off gas 7 discharged from the air electrode of the fuel cell 1. The amount of impurities contained in the recovered water, which is obtained by condensing the water contained in the water (generated water generated) and the water contained in the combustion exhaust gas 8 of the burner of the fuel reformer 2 (combustion generated water) has less impurities than tap water. Since the load of the ion-exchange type deionized water device can be reduced, a cooling water replenishing device including a produced water recovery system 20 and a water treatment system 30 is added to the fuel cell power generation device.

The produced water recovery system 20 is, for example, a produced water recovery tower 2 including a direct heat exchanger section and a recovered water tank section.
1 and a mixed water circulation in which the mixed water 26 obtained by adding tap water to the recovered water in the recovered water tank is sprayed from above the direct heat exchanger through the circulation pump 22, the heat exchanger 23 for cooling, and the nozzle 24. The mixed water sprayed from the nozzle and the air off gas 7 and the combustion exhaust gas 8 come into countercurrent contact with each other to collect the produced water.

A part of the mixed water 26 stored in the produced water recovery tower 21 is sent to a water treatment system 30 including an ion-exchange type deionized water device 31 via a pump 22 to remove impurities from the deionized water. Is supplied to the cooling water circulation system 10 to compensate for the shortage of the cooling water 6, and the decrease in the water level of the recovered water tank is maintained by supplying tap water from a tap water supply system (not shown) to maintain a constant water level. It

[0006]

In the conventional produced water recovery system 20, the mixed water tank in the produced water recovery tower 21 is empty at the beginning of the operation, and the operation is started after the water is first filled with tap water. To be done. Also, when the water level in the mixed water tank drops during operation, tap water is replenished.
These tap waters usually have microbial sterilization suppressed by chlorine sterilization, but contain trace amounts of bacteria as impurities. On the other hand, the off-gas 7 and 8 flowing through the fuel reformer burner in a high temperature atmosphere exceeding 200 ° C. and the fuel cell and flowing into the produced water recovery tower 21 are aseptic,
The recovered water obtained by condensing in the generated water recovery tower is also kept in a substantially pure water state and has no sterilizing ability. Furthermore, since the temperature of the mixed water in the mixed water tank is usually maintained at 40 to 60 ° C, it becomes a condition that microorganisms can easily propagate. Therefore, the microorganisms in the tap water replenished in the produced water recovery tower proliferate at an accelerated rate in the recovered water tank, and this is sent to the ion exchange type deionized water device 31 by the pump 22 and captured.
The ion exchange type pure water device 31 is in a closed state, and due to this, the pure water supply to the water vapor separator 11 is insufficient, the water balance is lost, and an operation failure occurs in the fuel reformer 2 and the fuel cell 1. At the same time, there arises a problem that the maintenance interval of the ion exchange type pure water device 31 becomes extremely short and the maintenance becomes complicated.

[0007] In addition, the microorganisms that have once grown in a large amount in the recovered water tank have to be removed by chemical cleaning or the like. In that case, the operation of the fuel cell is temporarily stopped and the fuel cell 1 and the fuel reformer 2 are connected. The pH of the washing water discharged outside the system while washing with tap water after sterilizing by injecting chemicals with the pipes blocked and circulating or standing for a certain period of time.
It is necessary to perform a complicated operation of monitoring the temperature and confirming neutralization before filling water with tap water, and there is a problem that maintenance work becomes complicated and the running cost of the fuel cell power generator increases. In addition, there is a problem in that a microbial growth environment is created by performing water filling with tap water again after the cleaning work is completed.

The object of the present invention is to eliminate the need for complicated maintenance work such as cleaning chemicals in the produced water recovery system and the water treatment system,
An object of the present invention is to provide a water-cooled fuel cell power generator that can prevent the growth of microorganisms.

[0009]

In order to achieve the above-mentioned object, the invention according to claim 1 provides a fuel cell comprising a laminate of a plurality of unit cells and cooling plates, and a cooling pipe for the cooling plates. A cooling water circulation system that circulates cooling water, a produced water recovery system that condenses and recovers water vapor in the exhaust gas of the fuel cell and the fuel reformer, and stores it as mixed water to which tap water is added, and the mixed water. A water-cooled fuel cell power generator including a cooling water replenishing device including a water treatment system that converts the water into pure water and supplies the cooling water circulation system with an antibacterial filter that prevents the growth of microorganisms in the mixed water.

Here, in the invention as set forth in claim 2, it is preferable to use, as the antibacterial filter, a granular adsorbent filling tank having an antibacterial metal film attached to the surface thereof. Further, in the invention according to claim 3, it is preferable that an antibacterial filter is provided in the mixed water circulation system which is provided in the produced water recovery system and makes the exhaust gas and the mixed water countercurrently contact. Further, in the invention according to claim 4, an antibacterial filter may be provided on the upstream side of the water treatment system.

[0011]

In the invention described in claim 1, when the mixed water passes through the antibacterial filter, microorganisms in the mixed water are captured by the filter, and the antibacterial property of the filter prevents the growth of the recovered water. By mixing tap water with the water, it is possible to capture and suppress the growth of microorganisms brought into the produced water recovery system, thus eliminating the blockage obstacle of the ion exchange type pure water device and extending the exchange interval of the ion exchange resin. As a result, pure water is stably supplied to the cooling water circulation system for a long time.

According to the second aspect of the present invention, since the antibacterial filter is provided with the antibacterial adsorbent filling tank having the antibacterial metal film attached to the surface thereof, the granular adsorbent absorbs the microorganisms in the mixed water. At the same time as being captured by the adsorptive power, the antibacterial metal film inhibits the growth of microorganisms captured by the antibacterial property, so that the amount of the microorganisms in the mixed water that has passed through the antibacterial filter is reduced.

According to the third aspect of the present invention, the antibacterial filter is provided in the mixed water circulation system which is provided in the produced water recovery system to bring the exhaust gas and the mixed water into countercurrent contact.
Since the mixed water stored in the generated water recovery tower is repeatedly filtered through the antibacterial filter, the accumulation and propagation of microorganisms that enter the generated water recovery tower are stopped by the supply of tap water during operation, and the amount of microorganisms The mixed water with reduced water is stably supplied to the water treatment system.

Further, in the invention according to claim 4, since the antibacterial filter is provided on the upstream side of the water treatment system, the amount of bacteria in the mixed water can be reduced immediately before the ion exchange type deionized water device. The blocking obstacle of the ion exchange resin can be eliminated more effectively, and the maintenance interval can be further extended.

[0015]

EXAMPLES The present invention will be described below based on examples.
Since the members having the same reference numerals as those of the conventional example have the same functions as those of the conventional example, the description thereof will be omitted. FIG. 1 is a simplified system configuration diagram showing an embodiment of a water-cooled fuel cell power generator of the present invention. In the figure, in the embodiment, an antibacterial filter 41 is provided in the mixed water circulation system 25 of the produced water recovery system 20, and an antibacterial filter 42 is also provided upstream of the pure water device 31 of the water treatment system 30. Two
As one antibacterial filter 40, an antibacterial activated carbon filling tank was used in which an antibacterial metal such as silver or copper was impregnated on the surface of activated carbon as a granular adsorbent within a range that did not significantly impair the adsorptive power of the activated carbon.

In the embodiment, since the mixed water 26 stored in the produced water recovery tower 21 is repeatedly filtered through the antibacterial filter 41, it is produced not only by the microorganisms invading at the time of water filling but also by supplying tap water during operation. Microorganisms that enter the water recovery tower are also captured by the adsorptive power of the granular activated carbon, and at the same time, the antibacterial metal membrane blocks the growth of the microorganisms that are captured due to their antibacterial properties, so the mixed water that has passed through the antibacterial filter is The amount of microorganisms is gradually reduced, and the mixed water 26 in which the amount of microorganisms is reduced is stably supplied to the water treatment system 30.

In addition, the mixed water supplied to the water treatment system 30 is filtered by the antibacterial filter 42 again for microorganisms, and adsorption filtration of other impurities contained in the mixed water is also performed. The mixed water supplied to the device 31 is in a state in which the amount of microorganisms and the amount of impurities are significantly reduced, and highly purified pure water 26P is replenished to the cooling water circulation system 10. As a result, in the conventional example, the ion-exchange type deionized water device 31 is closed due to the microorganisms that have acceleratedly grown in the produced water recovery tower 21, which causes insufficient supply of deionized water to the water vapor separator 11. As a result, a situation in which the water balance is lost and an operation failure occurs in the fuel reforming device 2 and the fuel cell 1 is avoided.
The maintenance interval was significantly extended compared to the conventional example. Also,
The chemical cleaning of the generated water recovery tower 21 is also unnecessary by regularly exchanging the antibacterial activated carbon of the antibacterial filter, the maintenance work is labor-saving, the operating cost is reduced, and the chemical cleaning is performed. Therefore, it is possible to avoid the operation stop of the fuel cell power generator, which is necessary, and there is an advantage that the long-term continuous operation of the fuel cell power generator can be achieved.

The antibacterial filters 41 and 42 may be arranged so as to be narrowed down to one of them to simplify the apparatus. Further, if the antibacterial filter 40 is composed of two parallel filling tanks that can be switched to each other, there is an advantage that the operation of periodically exchanging the antibacterial activated carbon can be performed without stopping the operation of the fuel cell power generator.

[0019]

As described above, the water-cooled fuel cell power generator according to the present invention is composed of, for example, a filling tank of antibacterial activated carbon for the microorganisms that enter the mixed water by supplying the generated water recovery system with tap water. An antibacterial filter was provided to capture and suppress its proliferation. As a result, the grown microorganisms block the ion exchange type deionized water device, and troubles such as difficulty in replenishing deionized water to the cooling water circulation system are avoided and a long-term continuous operation of the fuel cell power generation device becomes possible. The operating cost is also reduced by extending the ion-exchange resin replacement interval and eliminating maintenance work such as complicated chemical cleaning, so each water system can be operated without the need to shut down the fuel cell power generator or perform any complicated maintenance work. It is possible to provide a water-cooled fuel cell power generation device that can suppress the growth of microorganisms, and that has a low operating cost and high long-term reliability.

[Brief description of drawings]

FIG. 1 is a simplified system configuration diagram showing an embodiment of a water-cooled fuel cell power generator of the present invention.

FIG. 2 is a configuration diagram showing a main part of a conventional water-cooled fuel cell power generator.

[Explanation of symbols]

 1 Fuel Cell 2 Fuel Reforming Device 3 Cooling Plate 6 Cooling Water 6P Pure Water 7 Air Off-gas 8 Combustion Exhaust Gas 10 Cooling Water Circulation System 11 Steam Separator 12 Pump 20 Generated Water Recovery System 21 Generated Water Recovery Tower 22 Pump 23 Heat Exchanger 24 Nozzle 25 Mixed water circulation system 26 Mixed water 26P Pure water 30 Water treatment system 31 Ion exchange type pure water device 32 Pump 40 Antibacterial filter (41, 42)

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Motoichi Ikeda 2-6 B9, Hisagi, Zushi City, Kanagawa Prefecture (72) Nobuhiro Iwasa 910-55, Katsuragi Town, Kishiwada City, Osaka Prefecture (72) Inventor Tatsuya Ichihashi 1-27 Kanagawa-cho, Minato-ku, Nagoya-shi, Aichi Prefecture, A-106, Kanagawa company housing (72) Inventor Haruki Matsuda 1-1, Tanabe Nitta, Kawasaki-ku, Kawasaki-shi, Kanagawa Fuji Electric Co., Ltd. (72) Inventor Takashi Murakami 1-1, Tanabe Nitta, Kawasaki-ku, Kawasaki-shi, Kanagawa Prefecture Fuji Electric Co., Ltd.

Claims (4)

[Claims] 1. A fuel cell comprising a stack of a plurality of unit cells and a cooling plate, a cooling water circulation system for circulating cooling water in a cooling pipe of the cooling plate, and exhaust gas of the fuel cell and the fuel reformer. Cooling water replenishing device comprising a generated water recovery system for condensing and recovering the above water vapor and storing it as mixed water to which tap water has been added, and a water treatment system for converting the mixed water into pure water and supplying it to the cooling water circulation system A water-cooled fuel cell power generator comprising: a water-cooled fuel cell power generator including an antibacterial filter for inhibiting the growth of microorganisms in the mixed water. 2. The water-cooled fuel cell power generator according to claim 1, wherein the antibacterial filter comprises a granular adsorbent filling tank having an antibacterial metal film attached to the surface thereof. . 3. The water-cooled fuel cell power generator according to claim 1, wherein an antibacterial filter is provided in the mixed water circulation system which is provided in the produced water recovery system and makes the exhaust gas and the mixed water come into countercurrent contact. Water-cooled fuel cell power generator. 4. The water-cooled fuel cell power generator according to claim 1, further comprising an antibacterial filter provided upstream of the water treatment system.