JPH087906A - Fuel cell water treatment device - Google Patents

Abstract

(57) [Summary] [Purpose] To reduce maintenance costs. [Constitution] Water treatment system (L4) with continuous deionizer (2
1) is incorporated, and means (L7, 22, 2) for coping with the decrease in the amount of water in the water treatment system due to the discharge of concentrated water from the continuous deionization apparatus
2a, 26, 32).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water treatment device for a fuel cell.

[0002]

2. Description of the Related Art A conventional water treatment device for a fuel cell will be described with reference to FIG. The fuel cell, generally designated by reference numeral 1, comprises a stack of unit cells in which a fuel electrode 2, an air electrode 3, an electrolyte matrix 36, and a cooling plate 4 are arranged. The cooling water A of the cell cooling water system L1 is a cooling water circulation pump. Cooling plate 4 by 5
Is circulated through the steam separator 6.

The steam C of the steam separator 6 is sent to the reformer 8 and used for steam reforming of the raw fuel OF. Most of the steam-reformed raw fuel OF is consumed in the fuel cell 1, and the rest is burned in the reformer 8 to serve as a heat source for the steam reforming reaction. The combustion exhaust gas D from the reformer 8 merges with the exhaust gas G of the air electrode 3 and is supplied to the condenser 9, where the water condensed is recovered in the recovery water tank 10.

On the other hand, the battery cooling water system L is generated by the generation of steam.
In order to avoid the concentration of impurities in the cooling water circulating in 1, the blowdown water B is introduced to the recovered water tank 10 via the blowdown system L2 and the cooling heat exchanger 7.

The recovered water E in the recovered water tank 10 is supplied to the pump inlet filter 11, the pump 12 and the pump 12 by the water treatment system L4.
It is processed by the ion exchange resin device 14 through the ion exchange resin inlet filter 13. And the ion exchange resin device 1
The treated water F treated in 4 is sent by the pump 15 to the steam separator 6 by the amount of the battery cooling water lost due to steam generation and blowdown, and the rest is the recovered water tank 10
Is returned to.

Here, in order to insulate and prevent corrosion of the fuel cell 1, cell cooling water having a low electric conductivity is required. In order to secure this cell cooling water, an ion exchange resin is used in a conventional fuel cell water treatment device.

[0007]

However, since the ion exchange resin needs to be replaced at the time of breakthrough, the maintenance cost increases if the replacement frequency is high. On the other hand, it is possible to automatically regenerate the ion exchange resin, but this method has problems such as an increase in space and treatment of waste liquid.

The present invention has been proposed in view of the above problems of the prior art, and an object of the present invention is to provide a water treatment device for a fuel cell, which can reduce maintenance costs.

[0009]

The above-mentioned problems of the prior art are caused by the ion exchange resin accumulating the removed ions. On the other hand, the fuel cell water treatment apparatus of the present invention intends to solve the problem by incorporating a continuous deionization apparatus.

The continuous deionization apparatus uses an ion exchange membrane and an electric field to move ions from one of the water in the two flow paths to the other, thereby continuously deionizing water and water with concentrated ions. It uses the principle of generating and.
In this case, the ions are ejected together with the water on the concentration side,
There is no need for regular exchange such as ion exchange resin.

However, since water is discharged at the same time as the ions, it is necessary to recover a large amount of water only for the discharged water. Under the stable operating conditions of normal fuel cell devices, there is no problem because the amount of water equivalent to the wastewater of the continuous deionization device is collected, but due to changes in operating conditions such as the outside temperature and the output of the fuel cell device, There is a possibility that the amount of water recovered in the condenser will temporarily decrease and the amount of water in the water treatment system will become insufficient.

In the water treatment device for a fuel cell of the present invention, the water treatment system is provided with a continuous deionization device and means for coping with a reduction in the amount of water in the water treatment system due to the discharge of concentrated water of the continuous deionization device. ing.

Here, the above-mentioned "means for coping with the decrease in the amount of water in the water treatment system due to the discharge of concentrated water from the continuous deionization apparatus"
Is preferably constructed by interposing a three-way valve for switching the drainage system to the outside and the return system to the recovered water tank in the discharge system of the continuous deionization apparatus. Further, it is preferable that the recovered water tank is provided with a water level detecting means and a control means for controlling the switching of the three-way valve in response to the detection result of the water level detecting means. In addition to this, it is preferable to include means for outputting an alarm signal when the three-way valve is switched to the return system to the recovered water tank.

As the "means for coping with the decrease in the amount of water in the water treatment system due to the discharge of concentrated water from the continuous deionization apparatus", a control means for controlling the flow rate of condensed water supplied from the condenser to the recovered water tank. Is preferably provided. The recovered water tank is preferably provided with a water level detection means, and the output of the detection means is preferably transmitted to the control means. Further, it is preferable to include means for outputting an alarm signal when the flow rate of the condensed water supplied to the recovered water tank falls below a predetermined value.

Here, as the control means, the cooling capacity of the cooling tower provided in the condenser cooling water system is controlled (for example, by a method such as adjusting the rotation speed of the cooling fan of the cooling tower) to condense. A method of adjusting the water temperature of the cooling water for the vessel can be adopted. Alternatively, the flow rate of the condenser cooling water system is controlled by adjusting the capacity of the pump installed in the condenser cooling water system, or by providing a bypass circuit and adjusting the amount of water flowing through the bypass circuit. The method of adjusting the water temperature of can be adopted.

[0016]

In the water treatment device for a fuel cell configured as described above, the continuous deionization device separates and concentrates the ions and discharges the side having a high ion concentration (as waste water). Since it is not a "retractable type" like the above, it can be used for a long time without performing replacement work. Moreover, unlike the prior art in which the ion exchange resin is automatically regenerated, problems such as increase in space and waste liquid treatment do not occur.

By incorporating a continuous deionization apparatus in the water treatment system, the water treatment system is temporarily changed due to fluctuations in operating conditions such as fluctuations in ambient temperature and fluctuations in output (of the fuel cell device). The amount of water inside may decrease. When the amount of water in the water treatment system decreases, there is a possibility that inconvenience such as cavitation of the pump may occur, or the fuel cell device may stop because the cell cooling water runs out. On the other hand, the present invention is provided with means for coping with the reduction in the amount of water in the water treatment system due to the incorporation of the continuous deionization device.

When the amount of recovered water decreases, the wastewater of the continuous deionization device is not discharged to the outside, but the wastewater is returned to the recovered water tank so that the amount of water in the water treatment system does not become insufficient. , The operation of the fuel cell device can be continued. In this case, since the wastewater of the continuous deionization device is circulated, the quality of the water treated by the water treatment system is deteriorated, but if it is a short time or temporary, it will not be necessary to operate the fuel cell device. There is no obstacle.

Further, by detecting a decrease in the water level of the recovered water tank or the like by a detecting means such as a sensor, a shortage of water in the water treatment system is detected, and the switching of the three-way valve is controlled based on the detection signal. The above operations can be automatically performed by controlling the unit.

Further, by outputting an alarm signal when the three-way valve is switched to the side for returning the waste water of the continuous deionization device to the recovery water tank, the water treatment system is automatically or temporarily operated by the worker. You can know when to supply water from outside.

In addition to this, according to the present invention, when the amount of recovered water decreases, the saturated steam pressure is lowered by lowering the temperature of the condenser, and the amount of recovered water is increased to cause water shortage in the water treatment system. Therefore, it is possible to continue the operation of the fuel cell device. In this case, if the water level detecting means is provided in the recovered water tank or the means for outputting an alarm signal when the flow rate of the condensed water supplied to the recovered water tank falls below a predetermined value, the water level detecting means By monitoring the output of the above or the output of the means for outputting the alarm signal, it is possible to know the time when the water should be externally supplied to the water treatment system by an operator or automatically.

[0022]

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

The parts in FIG. 1 corresponding to those in FIG. 2 are designated by the same reference numerals to omit redundant description.

In FIG. 1, the pump 12 of the water treatment system L4.
An automatic backwash filter 20 and a continuous deionization device 21 are provided on the downstream side of. The deionization device 21
A discharge system L5 is connected to the concentrated water discharge side of. This drainage system L5 is a drainage system L to the outside by a three-way valve 22
6 or the return system L7 to the recovered water tank 10 can be selectively switched.

A cooling tower 30 is interposed in the condenser cooling water system 23 of the condenser 9, and the cooling capacity of the cooling tower 30 is controlled by adjusting the rotation speed of the cooling fan 31. A water level sensor 24 is provided in the recovered water tank 10. The water level sensor 24 and the cooling fan 31 are respectively connected to the control unit 26.
It is connected to the. The operating unit 22a of the three-way valve 22 is connected to the control unit 26, and the system L5 to L6 and the members 22 to 26 form a discharging unit.

Next, the operation will be described.

During operation, the continuous deionizer 21
The ions of the recovered water are separated and concentrated. The control unit 26 switches the three-way valve 22 to the return system L7 side when the water recovery rate is low and the amount of water flowing through the water treatment system becomes insufficient based on the water level signal from the water level sensor 24, for example. Wastewater from the continuous deionizer 21 is collected Water tank 1
Return to 0. This eliminates the shortage of recovered water. Alternatively, it is also possible to increase the rotation speed of the cooling fan 31 to lower the water temperature of the condenser cooling water system 23 and increase the amount of water condensed in the condenser 9 to eliminate the water shortage in the water treatment system. Is.

An alarm signal output means 32 (for example, a sensor) is provided in the control unit 26, and the alarm signal output means 32 returns the three-way valve 22 to the system L.
When switched to the 7 side, an alarm signal is output to an alarm means (alarm lamp, buzzer, etc.) not shown. By monitoring how long this alarm signal is output, it is possible to determine whether the water shortage in the water treatment system is temporary or long-term. When it is determined that there is a shortage of water for a long time, water may be supplied from outside the water treatment system by an operator or automatically.

When the amount of water condensed in the condenser 9 is increased to eliminate the water shortage in the water treatment system, the alarm signal output means 32 uses the system L10 to recover the recovered water tank 1.
The alarm signal is output when the flow rate of the condensed water supplied to 0 exceeds a predetermined value. Then, by monitoring this output, it is possible to determine whether the water shortage in the water treatment system is temporary or long-term. In addition,
The “predetermined value” of the condensed water flow rate is a numerical value determined on a case-by-case basis according to the structure of each fuel cell device, operating conditions, and the like.

It should be noted that the illustrated embodiments are merely examples and are not intended to limit the technical scope of the present invention.

[0031]

Since the present invention is configured as described above, it has the following effects.

(1) Since the continuous deionization apparatus can be used for a long time without replacement, maintenance cost can be reduced.

(2) Even if a water shortage occurs in the water treatment system,
It is possible to prevent the situation where the operation of the fuel cell device is stopped.

(3) A means for outputting an alarm signal when the three-way valve is switched to the return system to the recovered water tank or when the flow rate of condensed water supplied to the recovered water tank exceeds a predetermined value. If provided, it is possible to detect that it is necessary to supply water to the water treatment system from the outside.

[Brief description of drawings]

FIG. 1 is a system diagram showing an embodiment of the present invention.

FIG. 2 is a system diagram showing an example of a conventional device.

[Explanation of symbols]

 A ... Cooling water AR ... Air B ... Blowdown water C ... Steam D ... Combustion exhaust gas E ... Recovered water F ... Treated water G ... Air electrode exhaust OF ... ..Raw fuel L1 ... Battery cooling water system L2 ... Blowdown system L4 ... Water treatment system L5 ... Condensate discharge system L6 ... Drainage system L7 ... Return system L10 ... Condensation System for supplying water to the recovered water tank 1 ... Fuel cell 2 ... Fuel electrode 3 ... Air electrode 4 ... Cooling plate 5 ... Cooling water circulation pump 6 ... Water vapor separator 7 ...・ Heat exchanger 8 ・ ・ ・ Reformer 9 ・ ・ ・ Condenser 10 ・ ・ ・ Recovered water tank 11 ・ ・ ・ Pump inlet filter 12, 15 ・ ・ ・ Pump 13 ・ ・ ・ Ion exchange resin inlet filter 13A ・・ Filter 14 ・ ・ ・ Ion exchange resin device 21 ・ ・ ・ Continuous deionizer 2・ ・ ・ Three-way valve 22a ・ ・ ・ Operating part 23 ・ ・ ・ Condenser cooling water system 24 ・ ・ ・ Water level sensor 26 ・ ・ ・ Control unit 30 ・ ・ ・ Cooling tower 31 ・ ・ ・ Cooling fan 32 ・ ・ ・ Alarm signal output Means 36 ... Electrolyte matrix

Claims (6)

[Claims] 1. A fuel cell, comprising: a water treatment system provided with a continuous deionization device; and means for coping with a reduction in the amount of water in the water treatment system due to discharge of concentrated water from the continuous deionization device. Water treatment equipment. 2. A concentrated water discharge system of a continuous deionization device,
The water treatment device for a fuel cell according to claim 1, further comprising a three-way valve for switching between a drainage system to the outside and a return system to the recovered water tank. 3. The water treatment for a fuel cell according to claim 2, wherein the recovered water tank is provided with water level detection means, and control means is provided for controlling switching of the three-way valve in response to a detection result of the water level detection means. apparatus. 4. The water treatment device for a fuel cell according to claim 2, further comprising means for outputting an alarm signal when the three-way valve is switched to a return system to the recovered water tank. 5. The water treatment device for a fuel cell according to claim 1, wherein the control means for controlling the flow rate of the condensed water supplied from the condenser to the recovered water tank is provided to cope with the decrease in the amount of water in the water treatment system. 6. The recovered water tank is provided with water level detection means, and the output of the water level detection means is transmitted to the control means.
The water treatment device for a fuel cell according to 1.