JP2001232394A - Water treatment equipment for fuel cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce high purity water without using an ion exchange resin which requires frequent exchange by treating condensed water of a solid polymer-type fuel cell or city water being supplying water by using an electrical deionization device capable of continuously treating for a long period of time without maintenance. SOLUTION: A water treatment equipment for a fuel cell has a decarbonation means 2 for decarbonation treatment of condensed water recovered from the fuel cell, a reverse osmosis membrane device 6 for treating supplied water from the outside, an electrical deionization device 7 for treating treated water of the decarbonation means 2 and/or permeated water of the reverse osmosis membrane device 6, and switching means V2 and V3 for switching a flow passage for discharging at least a portion of the condensed water of the electrical deionization device 7 to the outside of the system and a flow passage for supplying at least a portion of the condensed water of the electrical deionization device 7 to the decarbonation means 2. Further, a water treatment equipment for a fuel cell has a reverse osmosis membrane device for treating the condensed water recovered from the fuel cell and/or supplied water from the outside, an electrical deionization device for treating permeated water of the reverse osmosis membrane device and a switching means for switching a flow passage for discharging at least a portion of condensed water of the electrical deionization device to the outside of the system and a flow passage for supplying at least a portion of the condensed water to the reverse osmosis membrane device.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water treatment apparatus for a fuel cell, and more particularly to a fuel treatment system comprising a reformer, a carbon monoxide converter and a carbon monoxide remover in a polymer electrolyte fuel cell. The present invention also relates to an apparatus for treating the humidification of fuel gas or air and the water supplied to a circulating cooling water system of a fuel cell body.

[0002]

2. Description of the Related Art FIG. 3 is a system diagram showing a general configuration of a polymer electrolyte fuel cell having a fuel processing system for producing hydrogen from city gas or the like, in which fuel is supplied via an electrolyte (not shown). Fuel cell body 3 provided with electrode 31 and air electrode 32
3 includes a pump P from the cooling water tank 34 for cooling.
₁ , cooling water is circulated.

[0003] Fuel such as city gas is introduced into a fuel processing system 35, reformed into a gas mainly composed of hydrogen in a reformer 35A, and a carbon monoxide component is converted in a carbon monoxide converter 35B. After the carbon monoxide is removed to an extremely low concentration by the carbon monoxide remover 35C, the carbon monoxide is supplied to the fuel electrode 31 in a state containing moisture for humidifying the fuel cell body.

The exhaust gas from the fuel electrode 31 is recovered by a heat recovery system including a pump P ₂ , heat exchangers 37, 38, 37 ′ and a hot water storage tank 39, and is further cooled by a radiator 40 to separate gas and liquid. Is introduced into the vessel 42. The separated water (condensed water) of the gas-liquid separator 42 is supplied to a water treatment device 36, and the separated gas containing a hydrogen component is used as a raw material of a reformer, and is discharged out of the system as steam after combustion. You. Pure water for generating steam for fuel treatment and humidification of fuel gas is introduced from the water treatment device 36 into the fuel treatment system 35.

On the other hand, air is introduced into the air electrode 32, and the reformed gas introduced into the fuel electrode 31 is oxidized by an oxygen reaction in the air by an electrochemical reaction to generate electric power. Pure water may be introduced from the water treatment device 36 in order to humidify the air introduced into the air electrode 32. Air electrode 32
Exhaust gas is pump P ₂ , heat exchangers 37, 38, 37 ′
After the heat is recovered by the heat recovery system including the hot water storage tank 39, it is further cooled by the radiator 40 and introduced into the gas-liquid separator 41. The separated water (condensed water) of the gas-liquid separator 41 is sent to the water treatment device 36, and the separated gas is discharged out of the system as exhaust gas.

[0006] Part of the pure water obtained by the treatment in the water treatment device 36 is sent to a fuel treatment system 35, and the rest is sent to a cooling water tank 34. Cooling water of the cooling water tank 34 by the pump P _1, the cooling unit of the fuel cell body 33, the heat recovery system is circulated through the radiator 40. In addition, tap water is introduced into the water treatment device 36 as makeup water, and is treated with circulating cooling water.

That is, in such a polymer electrolyte fuel cell, since the electrochemical reaction is carried out through a solid ion exchange membrane, high-purity water is indispensable for the transfer of hydrogen as a fuel. . In addition, a reformer that generates hydrogen from fuel gas also requires high-purity water. Furthermore, high-purity water is also required for the cooling water system of the fuel cell body.

In a fuel cell, when electric power is taken out by an electrochemical reaction, heat and water vapor are generated. In order to reduce the amount of water used, water vapor generated inside the fuel cell is condensed and collected. Although this is reused, carbon dioxide gas, Fe, Al, Cu, and the like are dissolved in the condensed water, so it is necessary to remove it by water treatment. In addition, since the amount of condensed water varies depending on the outside air temperature, the amount of high-purity water required inside the apparatus becomes insufficient. Therefore, it is necessary to continuously supply water with tap water or the like. It is also necessary to remove dissolved ions, carbon dioxide, and the like from this tap water.

For this reason, the condensed water is treated by the water treatment device 36 to be circulated and reused, and at the same time, the tap water is treated by the water treatment device 36 to replenish the water shortage.

[0010] Conventionally, as this water treatment apparatus, an apparatus for producing pure water by an ion exchange method using an ion exchange resin is used.

[0011]

According to the ion exchange method, high-purity water can be easily produced with an inexpensive and small-sized apparatus, but the ion exchange resin used in the ion exchange method is dissolved in water. The ion exchange capacity of the resin is limited because it is a mechanism for purifying water by adsorbing ionic substances and releasing H ⁺ ions and OH ⁻ ions instead. For this reason, if a certain amount of ions are adsorbed, the ability to produce pure water is lost, and it becomes necessary to exchange the ion exchange resin or regenerate the resin by chemicals.

On the other hand, a fuel cell operates as a power supply source. For this reason, it is desired that the fuel cell be operated at a high operation rate. However, in the case where the pure water production technology by the ion exchange method is adopted, a large amount of ion exchange is required to operate without replacing the ion exchange resin for one year. Requires resin and was not realistic.

Further, as described above, the exhaust gas from the fuel cell contains water vapor and carbon dioxide gas generated electrochemically. Therefore, condensed water obtained by cooling the exhaust gas and separating it by gas-liquid separation Also contains carbonic acid components. In the conventional method, this condensed water is recovered as it is and supplied to the water treatment apparatus in order to reduce the amount of makeup water (tap water). However, when such condensed water containing a large amount of carbon dioxide is treated, This carbon dioxide gas also acts as a load on the ion exchange resin, causing an increase in the frequency of ion exchange resin exchange.

[0014] The present invention solves the above-mentioned conventional problems, and uses a solid polymer type ion deionization apparatus capable of performing maintenance-free and long-term continuous processing without using an ion exchange resin that requires frequent replacement. An object of the present invention is to provide a water treatment device for a fuel cell, which manufactures high-purity water by treating tap water as condensed water and make-up water for the fuel cell.

[0015]

A water treatment apparatus for a fuel cell according to the present invention comprises: a decarbonation means for decarboxylation of condensed water recovered from the fuel cell; a reverse osmosis membrane apparatus for treating external make-up water; An electrodeionization device for desalinating the treated water of the decarbonation means and / or the permeated water of the reverse osmosis membrane device, and a flow path for discharging at least a part of the concentrated water of the electrodeionization device out of the system And a switching means for switching between a flow path to be supplied to the decarbonation means.

More specifically, the water treatment apparatus for a fuel cell comprises a decarbonation means for decarbonating condensed water recovered from the fuel cell, a first water storage tank for receiving external make-up water, A reverse osmosis membrane device for treating effluent from the first water storage tank, a second water storage tank for receiving condensed water decarbonated by the decarbonation means and / or permeate of the reverse osmosis membrane device, An electrodeionization device for desalinating the effluent from the water storage tank of No. 2, a channel for discharging at least a part of the concentrated water of the electrodeionization device out of the system, and a channel for supplying to the decarbonation means And switching means for switching between the two.

In this water treatment device for a fuel cell, it is preferable to perform a dechlorination treatment before treating the external make-up water with the reverse osmosis membrane device. In this case, the dewatering treatment is performed before or after the first water storage tank. It is preferable to provide a dechlorination means.

In this water treatment apparatus for a fuel cell, condensed water having a low ionic load and a high carbonic acid concentration is decarbonated and then subjected to a desalination treatment by an electric deionization apparatus. High-purity water can be produced by subjecting external make-up water having a low carbon dioxide concentration to desalting treatment with a reverse osmosis membrane device and an electrodeionization device. When the amount of condensed water is small based on the amount of condensed water, the amount of external replenishment water can be reduced by treating and reusing the concentrated water of the electrodeionization apparatus. Moreover, in this case, since the amount of condensed water to be treated by the decarbonation means is small,
There is no problem of increasing the load of the decarbonation means by decarbonating this concentrated water.

A water treatment apparatus for a fuel cell according to a third aspect of the present invention is a reverse osmosis membrane apparatus for treating condensed water and / or external make-up water recovered from the fuel cell, and desalinating the permeated water of the reverse osmosis membrane apparatus. And a switching means for switching between a channel for discharging at least a part of the condensed water out of the system and a channel for supplying the reverse osmosis membrane device.

More specifically, the water treatment apparatus for a fuel cell includes a water storage tank for receiving condensed water and / or external makeup water recovered from the fuel cell, and a reverse osmosis membrane for processing effluent from the water storage tank. Device, an electrodeionization device for desalinating the permeated water of the reverse osmosis membrane device, at least a part of the condensed water, a flow path selection for discharging outside the system, and a flow path selection for supplying the water storage tank. And switching means for switching between the two.

Also in this water treatment device for a fuel cell, it is preferable to perform a dechlorination treatment prior to treating the external make-up water with the reverse osmosis membrane device. In this case, a dechlorination means is provided before or after the water storage tank. Preferably, it is provided.

With this water treatment device for a fuel cell, high-purity water can be produced efficiently by reducing the amount of makeup water and the load on the device without using decarbonation means.

That is, in this apparatus, the reverse osmosis membrane apparatus cannot decarboxylate, but the electrodeionization apparatus pays attention to the fact that carbonic acid in water can be ionized and then removed by electrodialysis and desalination. Desalting condensed water up to the load limit of the ion device,
If the carbon dioxide concentration of the condensed water exceeds the load limit of the electrodeionization device, it is discharged out of the system.

[0024]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a system diagram showing an embodiment of a water treatment device for a fuel cell according to the first invention of the present invention, and FIG. 2 is a water treatment device for a fuel cell according to the second invention of the present invention. FIG. 2 is a system diagram showing an embodiment of the present invention.

The water treatment apparatus shown in FIG. 1 has a relatively low ion load, a high carbon dioxide concentration, a treatment system for decarbonating fuel cell condensed water, and then desalting with an electric deionizer. By treating external make-up water (usually tap water) having a low carbonic acid concentration but a high ion load in two systems, a reverse osmosis (RO) membrane device and a treatment system for desalination with an electrodeionization device, The purpose of the present invention is to produce high-purity water efficiently by reducing the load on the apparatus after reducing the make-up water by reusing the condensed water.

In FIG. 1, 1 is a dechlorination means, 2 is a decarbonation means, 3, 4, and 5 are a first water tank, a second water tank, and a third water tank, respectively, 6 is an RO membrane device, and 7 is an electric deionization device. , 8 are flow meters, 10 is a control unit, V _{1 to} V ₃ are valves, P ₁ , P
₂ is a pump.

In the polymer electrolyte fuel cell, when the amount of condensed water increases and decreases, for example, when the outside air temperature rises, the amount of condensed water decreases, and it is necessary to increase the amount of external makeup water. In the water treatment apparatus of FIG. 1, the amount of condensed water measured by the flow meter 8 is controlled by the control unit 10.
The following processing is performed when the condensed water amount is smaller than the set value and when the condensed water amount is larger than the set value.

[When the amount of condensed water is small]
If it is determined that the amount of condensed water is low,
Luv V ₁After increasing the opening degree of the electrodeionization device 7
To reduce external replenishment water by circulating and recycling concentrated water
Valve V₂Close the valve V₃Open the ion load
Condensed water with low and high carbon dioxide concentration is decarbonated by decarbonation means 2
After that, the water is fed to the second water tank 4, while the ion load is high.
External makeup water having a low carbon dioxide concentration passes through the first water tank 3 and is provided with an RO membrane.
Desalination treatment at the storage 6 and decarburization of the condensed water via the second water tank
Desalting is performed by an electrodeionization device 7 together with the acid-treated water. This
As a result, the dissolved ion component in the makeup water is
About 90% of the water is removed.
Trace ion components in the condensed water
Highly eliminated. This is supplied to the electrodeionization device 7
The replenishment water is desalted in advance by the RO membrane device 6, and
The condensed water is previously subjected to a decarboxylation treatment by the decarbonation means 2.
Therefore, the load on the electrodeionization device 7 is reduced. This electricity
The treated water (deionized water) of the deionizer 7 is supplied to the third water tank 5.
After that, it is sent to the fuel cell.

The concentrated water of the RO membrane device 6 is discharged to the outside of the system, and the concentrated water of the electrodeionization device 7 is circulated to the inlet side of the decarbonation means 2 and is decarbonated together with the condensed water. The deionization process is performed by the ion device 7. That is, the concentrated water of the electrodeionization apparatus 7 is condensed water having a low ion load and permeated water of the RO membrane apparatus 6 which has a high ion load but most of the ions are removed by the RO membrane apparatus 6 and the ion load is reduced. Is the concentrated water of the electrodeionization apparatus 7 using as raw water, the ion load is relatively low, and the carbonic acid that cannot be removed by the decarbonation means is concentrated by the electrodeionization apparatus 7 to increase the carbonic acid concentration. Since the water is obtained, the water is decarbonated by the decarbonation means 2 and then deionized by the electrodeionization device 7 to obtain high-purity water.

When the amount of condensed water is small as described above, the amount of external replenishment water can be reduced by circulating and reusing the concentrated water of the electrodeionization device 7.
In addition, in this case, since the amount of condensed water is small, the decarbonation means 2 has a sufficient treatment capacity, so that there is no inconvenience caused by treating the concentrated water of the electrodeionization apparatus 7.

The decarboxylation means is not particularly limited, and may be any of an air contact type and a gas permeable membrane type, but a gas permeable membrane type with a small size and a high carbon dioxide gas removal rate is preferable. It is.

In this case, if all of the concentrated water in the electrodeionization device 7 is circulated and reused,
Therefore, it is preferable to discharge a part of the concentrated water of the electrodeionization device 7 to the outside of the system because the ions concentrated to the concentrated water side cannot be discharged to the outside of the system. As a means for discharging a portion of the electrodeionization apparatus 7 concentrated water out of the system to open the valve V ₂ together intermittently closing the valve V _3, or slightly opens the valve V ₂ in a state of opening the valve V ₃ Or the concentrated water of the electrodeionization device 7 decarbonated by the decarbonation means 2 is supplied to the first water tank 3 and mixed with external replenishment water and treated by the RO membrane device 6 as described later. To discharge as concentrated water of the RO membrane device 6.

[When the amount of condensed water is large] If the control unit 10 determines that the amount of condensed water is large, the tap water introduction valve V
The _first opening is made smaller by reducing the replenishing amount of water, electrodeionization apparatus 7 retentate of so discharged outside the system, the valve V ₂ opens, the valve V ₃ is closed. Also in this case, the condensed water having a low ionic load and a high carbonic acid concentration is supplied to the second water tank 4 after being decarbonated by the decarbonating means 2, whereas the external makeup water having a high ionic load and a low carbonic acid concentration is The water is desalinated by the RO membrane device 6 through the first water tank 3, and further desalted by the electrodeionization device 7 together with the decarbonated water of the condensed water through the second water tank 4. The treated water of the electrodeionization device 7 is supplied to a third water tank 5
Through the fuel cell. The concentrated water of the electrodeionization device 7 is discharged out of the system together with the concentrated water of the RO membrane device 6.

As described above, when the amount of condensed water is large, the concentrated water of the electrodeionization device 7 is discharged out of the system. That is, since the carbon dioxide that could not be removed by the decarbonation means 2 is concentrated in the concentrated water of the electrodeionization device 7, the concentrated water is discharged out of the system. By discharging the concentrated water of the electrodeionization device 7 in this manner, an increase in load can be prevented.

It should be noted that tap water is usually used as the external replenishing water, and chlorine in the tap water degrades the RO film. Therefore, in the apparatus shown in FIG. Chlorine in tap water is removed. This dechlorination means 1
May be provided on the upstream side of the RO membrane device 6, and may be provided between the first water tank 3 and the RO membrane device 6.

As the dechlorination means, a dechlorination tower filled with activated carbon and / or a catalyst carrier (cobalt or the like can be used as a catalyst and a resin or activated carbon can be used as a carrier) can be used. An agent injection device or the like can be used, but an activated carbon packed tower or an activated carbon and catalyst packed tower which does not cause an increase in ion load is preferable.

In the apparatus shown in FIG. 1, the third water tank 5 is not always required, and the treated water of the electrodeionization apparatus 7 may be directly supplied to the fuel cell. Since there are three locations, a cooling water system, a reforming reaction section and a shift section of the reformer, and the conditions for supplying pure water are different from each other, it is preferable to provide the third water tank 5 in terms of stable supply.

In addition, a flow path for supplying water from the decarbonation means 2 to the first water tank 3 is provided, and a means for switching between this flow path and a flow path for supplying water to the second water tank 4 is provided. When the concentrated water of the ion device 7 is reused, the treated water of the decarbonation means 2 is supplied to the first water tank 3 instead of the second water tank 4, and after the decarbonation treatment, the RO membrane device 6 and A two-stage desalination process may be performed by the electrodeionization device 7.

[0040] That is, in the apparatus of FIG. 1, when the valve V ₂ closed, to deliver the total amount of concentrated water of the electrodeionization apparatus 7 a valve V ₃ is opened to the decarboxylation means, electrodeionization apparatus 7
In this case, it is impossible to discharge the ions concentrated in the concentrated water to the outside of the system. In this case, the treated water of the decarbonation means 2 is supplied to the first water tank 3 and is used as the concentrated water of the RO membrane device 6. It is preferable to discharge the concentrated ions out of the system.

In this apparatus, the amount of condensed water is determined based on the measurement result of the flow meter 8 provided in the condensed water inflow pipe as shown in FIG. The water tank 4 may be provided with a water level detecting means such as a water level meter, or the determination may be made based on the operation status of the RO membrane device 6, and the flow path switching of the concentrated water of the electrodeionization device 7 is performed as described above. It can be done automatically or manually based on a good judgment result.

In general, in polymer electrolyte fuel cells, most of the water recovered from the fuel cell is condensed water, and the amount of blow-down water of cooling water is very small. However, if there is blow-down water for cooling water, it is preferable to supply the blow-down water to the first water tank 3 or the second water tank 4 to mix with condensed water and / or make-up water for treatment.

Even when the amount of condensed water is considerably large, the amount of water in the system is reduced due to the discharge of a part of the concentrated water of the electrodeionization apparatus in which the dissolved substances in the condensed water are concentrated. The introduction of make-up water is required.

The water treatment apparatus shown in FIG. 2 is an apparatus for treating condensed water and external makeup water without using decarbonation means. It is intended to efficiently produce high-purity water by reducing the amount.

In FIG. 2, reference numeral 11 denotes a first water tank, and 12 denotes a first water tank.
2 water tank, 13 is dechlorination means, 14 is RO membrane device, 15 is
Electrodeionizer, 20 is a control unit, V₄, V₅Is bal
B, P ₃Is a pump.

In this water treatment apparatus, the following treatment is performed according to the carbon dioxide concentration of the condensed water.

[When Condensed Water Carbon Dioxide Concentration is Low] Control Unit 2
0 At low carbonate concentration of the feed water to the electrodeionization apparatus 15, when it is determined that the extent can be removed in an electrodeionization apparatus, stop the opening of the valve V _4, also the valve V ₅
Selects a flow path to the first water tank 11, performs a dechlorination treatment on the mixed water of the condensed water and the external makeup water by the dechlorination means 13 through the first water tank 11, and then performs a desalination treatment by the RO membrane device 14. Desalting and decarboxylation are performed by the electrodeionization device 15. This allows
The carbonic acid component in the condensed water having a low ionic load and a high carbonic acid concentration is removed by the electrodeionization device 15, and the ionic component in the makeup water having a high ionic load and the low carbonic acid concentration is removed by the RO membrane device 14 and the electric deionization device 15. Highly eliminated. The treated water (deionized water) of the electrodeionization device 15 is the second
The water is sent to the fuel cell via the water tank 12. RO membrane device 14
And the concentrated water of the electrodeionization device 15 is discharged out of the system.

As described above, by collecting and reusing the condensed water, the amount of makeup water can be reduced. In this case, since the carbon dioxide concentration of the condensed water is relatively low, the load on the apparatus is not excessively increased.

[When the Condensed Water Concentration is High] Control Unit 2
At 0, the carbon dioxide concentration of the condensed water is high,
When in is determined that not be removed, as well as increasing the supply amount of water by increasing the opening of the valve V _4, the channel selection so that the valve V ₅ discharges the entire amount or a portion of the condensed water out of the system Then, only make-up water or a mixture of make-up water and a small amount of condensed water is dechlorinated by the dechlorination means 13 through the first water tank 11, and then subjected to desalination treatment by the RO membrane device 14, and further to an electrodeionization device. Desalting and decarboxylation treatment is carried out at 15. The concentrated water in the RO membrane device 14 and the electrodeionization device 15 is discharged out of the system. When the carbon dioxide concentration of the condensed water is relatively high as described above, at least a part of the condensed water is discharged to the outside of the system without being reused, thereby increasing the load on the apparatus and reducing the quality of the treated water. Prevention can produce high-purity water.

Also in this apparatus, the R of the RO film apparatus 14
In order to prevent the deterioration of the O film, a dechlorination means 13 for dechlorinating tap water as external replenishment water is provided. The dechlorination means 13 supplies replenishment water upstream of the RO membrane device 14. Any treatment can be performed, and it may be provided on the introduction side of the first water tank 11. As the dechlorination means, the same means as those in FIG. 1 can be used.

Also in the apparatus shown in FIG. 2, the second water tank 12 is not necessarily required, but it is preferable to provide the second water tank 12 from the viewpoint of stabilizing the amount of pure water supplied to the fuel cell.

When the blowdown water of the fuel cell cooling water is also treated by this apparatus, the blowdown water is supplied to the first water tank 11 and mixed with the condensed water and / or make-up water for treatment. Is preferred.

In the apparatus shown in FIG. 2, the decision whether to reuse or discharge the condensed water is made based on the carbonic acid concentration of the condensed water. The voltage, current or treated water quality can be measured and determined based on these results.

That is, in the electrodeionization apparatus, when the concentration of the ionic component dissolved in the supply water and the concentration of the carbon dioxide gas increase, the specific resistance of the treated water decreases, and the operation current increases with respect to the operation voltage. Changes appear. If the water supplied to the electrodeionization device is limited to the permeated water of the RO membrane device, most of the ionic components are removed by the RO membrane device, but the carbon dioxide gas is contained in the permeated water without being removed. Those that affect the treated water specific resistance, operating voltage, and current of the electrodeionization device in the state are dominated by the carbon dioxide gas concentration. Therefore, the treated water specific resistance of the electrodeionization device,
The operating voltage and current are measured, and the carbon dioxide concentration can be estimated.

In addition to the indirect determination of the carbon dioxide concentration of the condensed water from the operating conditions of the electrodeionization apparatus, the carbon dioxide gas concentration varies from the inside of the first water tank 11 to the permeated water of the RO membrane apparatus. Since it is considered that there is no change, the carbon dioxide concentration may be measured directly at any point.

As a method of switching the flow path based on the carbon dioxide concentration of the condensed water, the following methods are adopted, the following methods are adopted, and further, the following methods are used.
A method of adjusting the amount of out-of-system discharge based on the concentration of carbon dioxide in the condensed water can be considered, but in any case, as described above,
Makeup water is essential because the amount of water in the system decreases. When the concentration of carbonic acid in the condensed water is low,
The water is supplied to the water tank 11 for circulating reuse. When the carbon dioxide concentration of the condensed water is relatively high, a part of the condensed water is sent to the first water tank 11 for circulating and reuse, and the remainder is discharged out of the system. When the carbon dioxide concentration of the condensed water is high, the entire amount of the condensed water is discharged out of the system.

The switching of the flow path may be performed manually or automatically.

According to the apparatus shown in FIG. 2, the maximum amount of condensed water can be recovered so that the water treatment apparatus is not overloaded, the amount of tap water used can be reduced, and complicated equipment can be used. The electrodeionization apparatus can be operated stably, and as a result, high-purity water can be continuously produced.

[0059]

As described in detail above, according to the water treatment apparatus for a fuel cell of the present invention, the amount of external replenishment water and the load on the apparatus are reduced by using an electrodeionization apparatus capable of continuously collecting water. In addition, high-purity water can be efficiently produced.

In particular, in the fuel cell water treatment apparatus according to the first aspect, the external replenishment water amount can be reduced as much as possible while suppressing an increase in the apparatus load according to the recovered condensed water amount.

In the fuel cell water treatment apparatus according to the third aspect, high-purity water can be produced by an inexpensive and small-sized apparatus without using complicated facilities.

[Brief description of the drawings]

FIG. 1 is a system diagram showing an embodiment of a water treatment device for a fuel cell according to the present invention.

FIG. 2 is a system diagram showing another embodiment of the water treatment device for a fuel cell of the present invention.

FIG. 3 is a system diagram showing a general configuration of a polymer electrolyte fuel cell having a fuel processing system for producing hydrogen from city gas or the like.

[Explanation of symbols]

 1,13 Dechlorination means 2 Decarbonation means 3,11 First water tank 4,12 Second water tank 5 Third water tank 6,14 RO membrane device 7,15 Electrodeionization device 10,20 Control unit 31 Fuel electrode 32 Air electrode 33 fuel cell main body 34 cooling water tank 35 fuel processing system 36 water treatment device 40 radiator 41 gas-liquid separator 42 gas-liquid separator

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[Procedure amendment]

[Submission date] March 7, 2000 (200.3.7)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0004

[Correction method] Change

[Correction contents]

The exhaust gas from the fuel electrode 31 is recovered by a heat recovery system including a pump P ₂ , heat exchangers 37, 38, 37 ′ and a hot water storage tank 39, and is further cooled by a radiator 40 to separate gas and liquid. Is introduced into the vessel 42. Separated water of the gas-liquid separator 42 (condensed water) is supplied to the water treatment device 36, the separation gas containing hydrogen component is utilized as fuel in the reformer, discharged from the system as post-combustion steam Is done. Pure water for generating steam for fuel treatment and humidification of fuel gas is introduced from the water treatment device 36 into the fuel treatment system 35.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B01D 61/02 B01D 61/02 5H027 C02F 1/20 C02F 1/20 A 1/28 1/28 F 1 / 44 1/44 E 1/46 ZAB 1/46 ZABZ H01M 8/06 H01M 8/06 W 8/10 8/10 (72) Inventor Tomoaki 3-4-7 Nishishinjuku, Shinjuku-ku, Tokyo Kurita Industrial Co., Ltd. In-house (72) Inventor Hiroshi Horinouchi 1-16-25 Shibaura, Minato-ku, Tokyo Tokyo Gas Co., Ltd.F-term in the Research and Development Department Basic Technology Research Laboratories 4D006 GA03 KA01 KB01 KB12 KB17 PB07 PC80 4D024 AA09 AB11 BA02 BB01 BC01 CA01 DB01 DB05 DB09 4D037 AA08 AB11 BA23 BB01 BB02 BB05 CA01 CA03 CA04 4D061 DA05 DB18 EA02 EB01 FA03 FA06 FA09 5H026 AA06 5H027 AA06 BA01 BA17 DD00

Claims (4)

[Claims] 1. A decarboxylation unit for decarboxylating condensed water recovered from a fuel cell, a reverse osmosis membrane device for processing external make-up water, a treated water of the decarbonation unit and / or the reverse osmosis membrane device An electrodeionization apparatus for desalinating the permeated water of the above, and a switching means for switching a flow path for discharging at least a part of the concentrated water of the electrodeionization apparatus out of the system and a flow path for supplying to the decarbonation means A water treatment device for a fuel cell, comprising: 2. The water treatment apparatus for a fuel cell according to claim 1, wherein a dechlorination means for dechlorinating the external make-up water is provided in a stage preceding the reverse osmosis membrane device. 3. A reverse osmosis membrane device for treating condensed water and / or external make-up water recovered from a fuel cell; an electrodeionization device for desalinating permeated water of the reverse osmosis membrane device; A water treatment apparatus for a fuel cell, comprising: a switching unit that switches between a flow path for discharging at least a part of the flow out of the system and a flow path for supplying the reverse osmosis membrane device. 4. The water treatment device for a fuel cell according to claim 3, wherein a dechlorination means for dechlorinating the external make-up water is provided in a stage preceding the reverse osmosis membrane device.