JPH09306524A - Water cooled fuel cell power generating system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obstruct propagation of microbes in the mixed water, keep stable cooling performance, and reduce the running cost by arranging a sterilizing means generating copper ions in the mixed water in a water treatment system to utilize the sterilization of the copper ion. SOLUTION: A sterilizing means 50 for generating copper ions, arranged in a water treating system 40 constituted with a produced water recovering line 20 and a water treating line 30 is immersed and set in mixed water 28 within a mixed water tank 22, and elutes a copper ion Cu<2+> by reaction with a base or oxygen in the mixed water. The eluted copper ions come ion contact with microbes in a process in which recovered water 29 and tap water are mixed in a fluid state within the mixed water tank 22, and the propagation of microbes in the mixed water is obstructed by the sterilizing action for obstructing a metabolism of the microbe by the sterilization of the copper ion. The clogging of a filter 32 caused by the proliferated microbes is avoided, and the supply of steam for reformation to a fuel reforming device 2 is stabilized.

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 means for inhibiting the growth of microorganisms brought into tap water in a produced water recovery system.

[0002]

2. Description of the Related Art FIG. 4 is a system configuration diagram showing a main part of a conventional water-cooled fuel cell power generator.
Is a stack of unit cells in which a fuel electrode and an air electrode are arranged with a matrix holding phosphoric acid sandwiched between them, and the fuel gas 2F generated in the fuel reformer 2 is supplied to the fuel electrode,
By supplying air to the air electrode, power generation is performed based on an electrochemical reaction. In addition, the electrochemical reaction of the fuel cell 1 is an exothermic reaction as a whole, and cooling of the fuel cell is necessary to maintain the temperature of the fuel cell 1 at an operating temperature of, for example, about 190 ° C. and perform efficient power generation operation. Will be needed.
Therefore, the fuel cell 1 has a cooling plate 3 that uses pure water as the cooling water 6.
Are laminated, and in order to circulate the cooling water 6 through the cooling plate 3, a steam separator 11 and a circulation pump 12, and a heat exchanger 1 for cooling (not shown) provided as necessary.
A cooling water circulation system 10 including 3 and the like is provided.

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 as the raw fuel, and a part of the steam separated by the steam separator 11 by the ejector 4 is supplied to the fuel reforming device 2 in a mixed state as reforming steam. Therefore, it is necessary to supply the pure water 9 to the cooling water circulation system 10 in accordance with the amount of steam used for reforming the fuel. The pure water 9 contains, for example, a pump 31 and a filter 3.
2, and ion-exchanged water from which impurities have been removed is used in a water treatment system 30 including an ion-exchange water treatment device 33. However, the water contained in the air off-gas 7 discharged from the air electrode of the fuel cell 1 (power generation) Water) and water contained in the combustion exhaust gas 8 of the burner of the fuel reformer 2 (combustion produced water)
Since the recovered water 29 in which the water is condensed has less impurities than tap water, and the load on the ion exchange type processing device 33 can be lightened accordingly, the air off gas 7
Generated water comprising a generated water recovery device 21 for condensing water vapor contained in the inside and combustion exhaust gas 8 and recovering it as recovered water 29, and a recovered water tank 22 for storing it as a mixed water 28 obtained by adding tap water to the recovered water 29. A recovery system 20 is provided,
A water treatment system 40 is configured together with the water treatment system 30.

A part of the mixed water 28 stored in the mixed water tank 22 is sent to a water treatment system 30 including a filter 32 and an ion exchange type water treatment device 33 through a pump 31.
Pure water 9 from which impurities have been removed is supplied to the cooling water circulation system 10 to compensate for the shortage of the cooling water 6, and tap water is supplied from a makeup water system 23 such as tap water to reduce the water level in the recovered water tank 22. This maintains a constant water balance.

[0005]

In the conventional water-cooled fuel cell power generator having the above-described structure, the fuel cell 1
When the load is large and the load is large, the amount of water vapor contained in the exhaust gases 7 and 8 is large, and the water balance of the cooling water circulation system 10 and the produced water recovery system 20 is easily maintained. However, when the amount of water vapor in the exhaust gas is small, such as when the load is low, or when the temperature of the cooling water of the produced water recovery device 21 rises, such as in summer, the amount of recovered water 29 decreases and the water balance cannot be maintained. appear. Therefore, mixed water tank 2
2 is provided with a makeup water system 23 for tap water such as city water, and the shortage of the recovered water 29 is supplemented with tap water and supplied to the water treatment system 30 as a mixed water 28 to take measures for maintaining water balance. It Further, the mixed water tank 22 is empty at the beginning of the operation of the fuel cell power generator, and the operation is started after the water is first filled with tap water. Also, when the water level in the mixed water tank drops during operation, tap water is replenished.

[0006] These tap waters usually contain a trace amount of surviving bacteria, although the growth of microorganisms (bacteria) is suppressed by chlorine sterilization. On the other hand, the exhaust gases 7 and 8 flowing through the fuel reformer burner in a high temperature atmosphere exceeding 200 ° C and the fuel cell 1 and flowing into the produced water recovery device 21 are in a sterile state and are condensed in the produced water recovery device 21. The recovered water 29 obtained as a result is also maintained in a substantially sterile state and has no sterilizing ability. Furthermore, the temperature of the mixed water in the mixed water tank 22 is the allowable temperature of the ion exchange type water treatment device 33.
Since the temperature is maintained at 0 to 50 ° C, there are cases where conditions under which microorganisms can easily propagate are set. For this reason, the microorganisms in the tap water replenished in the mixed water tank 22 are acceleratedly proliferated in the recovered water tank and are captured by the filter 32, and the filter serves as a medium to further propagate the microorganisms.
Is blocked, and due to this, the supply of pure water to the water vapor separator 11 is insufficient, the water balance in the cooling water circulation system 10 is lost, and an operation failure occurs in the fuel reformer 2 and the fuel cell 1. Occurs. In addition, the service life of the filter 32 becomes extremely short, and maintenance and management for replacing the filter medium becomes complicated.

[0007] Chemical solution cleaning is known as a method for removing microorganisms that have once grown in large quantities in the recovered water tank. However, since the constituent materials of the water treatment system are mainly made of SUS, chlorine-based chemicals are used. Injecting is not preferable, and the maintenance period of the fuel cell power generator is prolonged because of the need for sufficient deionized water cleaning after chemical injection, and the maintenance work is complicated, resulting in the running cost of the fuel cell power generator. There is a problem of causing rise in Further, there is a problem that the environment for the growth of microorganisms is recreated by refilling with tap water after completion of the cleaning work.

An object of the present invention is to eliminate the need for complicated maintenance work such as cleaning chemicals in a produced water recovery system and a 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 into the cooling water, and a generated water recovery device that condenses and recovers water vapor in the exhaust gas of the fuel cell and the fuel reformer, and a mixed water obtained by adding tap water to the recovered water. In a water-cooled fuel cell power generator comprising a water treatment system including a produced water recovery system including a mixed water tank that stores the water as a water supply and a water treatment system that converts the mixed water into pure water and supplies the pure water to the cooling water circulation system. A sterilizing means for generating copper ions is provided in the mixed water in the water treatment system.

According to the second aspect of the present invention, in the water-cooled fuel cell power generator according to the first aspect, the sterilizing means may be a copper member provided in the mixed water tank.
Further, in the invention described in claim 3, in the water-cooled fuel cell power generator according to claim 2, the copper member may be configured by a copper net provided in the mixed water tank. Further, the invention according to claim 4 is, in the water-cooled fuel cell power generator according to claim 2, a tubular copper net provided with a copper member in a mixed water tank, and the inside of the tubular copper net. It is convenient to construct it with a Raschig-ring-shaped copper material piece filled in.

According to the first aspect of the present invention, the toxicity of copper ions generated from the sterilizing means provided in the mixed water hinders the substance metabolism of the microorganisms. Therefore, the growth of the microorganisms brought into the water treatment system by tap water is increased. However, it is blocked regardless of a method such as chemical cleaning. Here, in the invention described in claim 2, the copper member is gradually dissolved by the reaction with the base and oxygen in the mixed water to form a sterilizing means that functions as a generation source of copper ions (Cu ²⁺ ).

Further, in the invention according to claim 3, since the copper member is a copper net provided in the mixed water tank, the recovered water and the tap water are mixed by the water flow in the mixed water tank. A sterilizing means that can secure a wide elution surface area of copper ions with a small amount of copper material without hindering is formed.
Further, in the invention according to claim 4, by filling the Raschig ring-shaped copper material pieces in the tubular copper net, the copper ion elution surface area is controlled by the filling amount of the Raschig ring-shaped copper material pieces. In other words, the control of the copper ion concentration is facilitated, the copper ion concentration is high, and a sterilizing means excellent in sterilization action is easily formed.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on embodiments. 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 system configuration diagram schematically showing one embodiment of the water-cooled fuel cell power generator of the invention described in claim 1 or 2. In the figure, a sterilizing means 50 for generating copper ions, which is provided in a water treatment system 40 composed of a produced water recovery system 20 and a water treatment system 30, is made of a copper member in this embodiment, and the produced water recovery system is used. It is provided in a mixed water tank 22 of 20 so as to be immersed in the mixed water 28, and reacts with a base and oxygen in the mixed water to elute copper ions (Cu ²⁺ ). The eluted copper ions come into contact with microorganisms in the process of mixing the recovered water 29 and tap water in the mixed water tank 22 in a fluidized state, and due to the sterilizing action of inhibiting the substance metabolism of the microorganisms due to the toxicity of copper ions, the mixed water is mixed. The growth of microorganisms of

Therefore, the amount of microorganisms contained in the mixed water 28 supplied to the water treatment system 30 from the mixed water tank 22 is extremely small, and the microorganisms captured by the filter 32 further propagate as the medium of the filter 32. The situation in which the filter 32 is blocked is avoided, the stable supply of the pure water 9 to the cooling water circulation system 10 maintains the water balance in the cooling water circulation system 10, and the cooling performance of the fuel cell 1 and the fuel reformer 2 The advantage of being able to stabilize the supply of the reforming steam is obtained. Further, since the frequency of replacement of the filter medium of the filter 32 is reduced and the maintenance work is simplified accordingly, the running cost of the fuel cell power generator can be reduced. Furthermore, when the surface of the copper member is covered with an impurity layer due to long-term use and the elution amount of copper ions is reduced, a new copper member is additionally charged into the mixing tank 22, or a new copper member is added. The sterilization effect can be restored by replacing the
Since there is no need to clean the liquid chemicals such as filters, it is possible to shorten the operation stop time of the fuel cell power generator, further simplify the maintenance work, and further reduce the running cost.

FIG. 2 is a sectional view of an essential part showing an embodiment of the fuel cell power generator according to claim 3, which is different from the above embodiment in that the sterilizing means 51 made of a copper member is a copper net. ing. In the case of this embodiment, the sterilizing means 51 is composed of a plurality of cylindrical copper nets coaxially arranged in the mixed water tank 22, so that the recovered water and the tap water due to the flow of water in the mixed water tank 22 are provided. A wide elution surface area of copper ions can be secured with a small amount of copper material without hindering the mixing of water.

It is known that the toxicity of copper ion (Cu ²⁺ ) differs in lethal concentration and patience concentration depending on the type of microorganism and contact time. Moreover, the concentration of copper ions eluted from the copper net changes under the influence of the water quality and temperature of the mixed water. Therefore, the amount of the copper net provided in the mixed water tank 22 can only be obtained by an experiment in consideration of the above conditions at the installation location of the fuel cell power generator. However, since the sterilizing means 51 is a copper net, it is easy to adjust the input amount of the copper net by the number of stacked copper nets and the mesh, and the sterilizing means 51 capable of eluting copper ions of the optimum lethal concentration is provided. The advantage is that it can be easily formed.

FIG. 3 is a sectional view of an essential part showing an embodiment of the invention described in claim 4. This embodiment differs from the embodiment shown in FIG. 2 in that the sterilizing means 52 has a plurality of cylinders. The point is that it is configured as a composite of a copper mesh 53 in the shape of a cylinder and a copper material piece 54 in the shape of a Raschig tube filled in the plurality of cylindrical copper meshes 53. According to this embodiment, since the Raschig tube-shaped copper material piece 54 can secure a large elution surface area with a small amount of copper, there is an advantage that a sterilizing means requiring a particularly high lethal concentration can be easily formed. .

[0018]

As described above, the present invention is constructed such that the sterilizing means for generating copper ions is provided in the mixed water in the water treatment system. As a result, the toxicity of copper ions can be used to prevent the growth of microorganisms in the mixed water without the need for chemical cleaning.Therefore, clogging of the filter by the grown microorganisms, which was a problem in the prior art, and the cooling water circulation system Disturbance of water balance is eliminated, stable cooling performance of the fuel cell power generator and reforming reaction water supply performance are maintained, and
The frequency of replacing the filter medium of the filter is reduced, and the advantage that it can contribute to the reduction of the maintenance cost and the running cost of the fuel cell power generator is obtained.

If the sterilizing means is provided in the mixed water tank as a copper member such as a copper net or a Raschig ring-shaped copper material piece, the copper material with a small lethal concentration of copper ions necessary for sterilization of microorganisms can be obtained. The amount can be easily obtained, and the convenience that the copper member can be added or updated without stopping the operation is obtained.

[Brief description of drawings]

FIG. 1 is a system configuration diagram showing in simplified form one embodiment of a water-cooled fuel cell power generator of the invention according to claim 1 or claim 2.

FIG. 2 is a cross-sectional view of a main part showing an embodiment of the fuel cell power generator according to claim 3;

FIG. 3 is a sectional view of an essential part showing an embodiment of the invention described in claim 4;

FIG. 4 is a system configuration diagram showing a main part of a conventional water-cooled fuel cell power generator.

[Explanation of symbols]

1 ... Fuel cell, 2 ... Fuel reformer, 3 ... Cooling plate, 6 ... Cooling water, 7 ... Air off-gas, 8 ...
・ Combustion exhaust gas, 9 ... Pure water, 10 ... Cooling water circulation system, 11 ... Water vapor separator, 12 ... Circulation pump,
13 ... Cooling heat exchanger, 14 ... Ejector, 20
... Generated water recovery system, 21 ... Generated water recovery device, 22
... Mixed water tank, 23 ... Makeup water system, 28 ...
Mixed water, 29 ... Recovered water, 30 ... Water treatment system, 31
... Pump, 32 ... Filter, 33 ... Ion exchange water treatment device, 40 ... Water treatment system, 50 ...
-Sterilizing means (copper member), 51 ... Sterilizing means (copper net), 52 ... Sterilizing means (copper net + Raschig tube-shaped copper material piece).

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical indication location C02F 1/50 540 C02F 1/50 540E 550 550B (72) Inventor Tatsuya Ichihashi Minato-ku, Nagoya, Aichi 1-27, Kanagawa-cho (72) Takashi Ouchi 1-1, Tanabe Nitta, Kawasaki-ku, Kawasaki-shi, Kanagawa Prefecture Fuji Electric Co., Ltd. (72) Harumi Miyama 1, Nitta Tanabe, Kawasaki-ku, Kanagawa-ken No. 1 in Fuji Electric Co., Ltd. (72) Inventor, Yutaka Fujii 1-1, Tanabe Nitta, Kawasaki-ku, Kawasaki-shi, Kanagawa Fuji Electric Co., Ltd.

Claims (4)

[Claims] 1. A fuel cell comprising a stack of a plurality of unit cells and a cooling plate is cooled by a cooling water circulation system that circulates cooling water through a cooling pipe of the cooling plate, and the fuel cell and the fuel reformer are also provided. Generated water recovery device that condenses and recovers water vapor in the exhaust gas of the device, and a generated water recovery system that consists of a mixed water tank that stores the mixed water with tap water added to the recovered water, and converts the mixed water into pure water In a water-cooled fuel cell power generator equipped with a water treatment system comprising a water treatment system for supplying to the cooling water circulation system, sterilizing means for generating copper ions is provided in the mixed water in the water treatment system. A water-cooled fuel cell power generator featuring. 2. The water-cooled fuel cell power generator according to claim 1, wherein the sterilizing means is a copper member provided in the mixed water tank. 3. The water-cooled fuel cell power generator according to claim 2, wherein the copper member is a copper net provided in the mixed water tank. 4. The water-cooled fuel cell power generator according to claim 2, wherein a copper member is provided with a tubular copper net in the mixed water tank, and a Raschig battery filled in the tubular copper net. A water-cooled fuel cell power generation device comprising a ring-shaped piece of copper material.