JP2011009130A - Fuel cell system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel cell system suppressing the propagation of microorganisms in condensed water.SOLUTION: The fuel cell system includes a hydrogen producing device 1, a fuel cell 2, a pure water tank 15, a condensed water tank 8 storing condensed water of anode offgas and cathode offgas, a combustion exhaust gas condensed water tank 10 storing combustion exhaust gas condensed water, and a pure water supply passage 14 including an organic matter removing device 13a and an ion removing device 13b midway in the passage, and the propagation of microorganisms in the pure water supply passage and components in the passage is suppressed by supplying the combustion exhaust gas condensed water to the pure water supply passage during the stop of power generation.

Description

  The present invention relates to a fuel cell system that can suppress the growth of microorganisms in the water path in the system and can be operated without maintenance for a long period of time.

  In general, when generating power in a fuel cell system, for reforming reaction in a hydrogen generator that generates hydrogen-rich reformed gas from fuel gas, humidification of air supplied to the fuel cell, and cooling of the fuel cell Need to supply pure water. On the other hand, when power is generated in the fuel cell system, reaction product water in the fuel cell and combustion product water in the hydrogen generator are generated, and these are collected as condensed water in a condensed water tank, and the condensed water is collected in the water purification device. After the water purified by passing the water is stored in a pure water tank, the pure water is used as water necessary for power generation in the fuel cell system. In this way, the fuel cell system has a water path through which condensed water is stored and circulated. However, since this condensed water is basically pure water that does not contain chlorine, microorganisms are likely to be generated. Occasionally, the operation and operation of the fuel cell system may be defective.

  In order to deal with such problems, for example, a fuel cell system described in Patent Document 1 has been proposed. FIG. 7 shows a conventional fuel cell system described in Patent Document 1. In FIG.

  In FIG. 7, a fuel cell 102 is a laminate composed of an anode electrode and a cathode electrode. The reformed gas generated by the hydrogen generator 101 is supplied to the anode electrode, and air is supplied to the cathode electrode, thereby causing an electrochemical reaction. Power generation is performed based on this. Since the fuel cell is an exothermic reaction, in order to circulate the cooling water in the fuel cell, a cooling water circulation system including a water vapor separator 103, a cooling water circulation pump 104, and a heat exchanger 105 for cooling provided as necessary. 106 is provided.

  In addition, in order to reform the fuel gas into a hydrogen-rich reformed gas, a part of the steam separated by the steam separator 103 is supplied to the hydrogen production apparatus as reforming steam.

  Therefore, it is necessary to replenish the cooling water circulation system 106 with pure water corresponding to the amount of water vapor used for reforming the fuel gas. As the pure water, ion-exchanged water from which impurities have been removed by a water treatment device 109 such as a pure water supply pump 107, a filter 108, and an ion-exchange water treatment device is used, but is discharged from the cathode electrode of the fuel cell 102. The use of water contained in the cathode off-gas or recovered water obtained by condensing water contained in the combustion exhaust gas of the hydrogen generator 101 has less impurities than tap water, and the load on the ion-exchange water treatment device 109 is correspondingly reduced. Can be lightened. Therefore, the fuel cell system is provided with a generated water recovery device 110 that condenses water vapor contained in the cathode offgas and combustion exhaust gas and recovers it as recovered water. A mixed water tank 111 for storing mixed water to which makeup water is added is provided.

  The recovered water collected in the fuel cell system does not contain sterilizing components such as chlorine, and the temperature is suitable for the growth of microorganisms. Becomes blocked, and pure water is not supplied to the fuel cell or the hydrogen generator, resulting in a system operation error. Moreover, since the trace amount microbe is contained in the city water supplied for water balance, the tendency becomes more remarkable.

  In order to cope with such a problem, it has been proposed in the prior art to provide a water treatment device 112 that converts makeup water such as city water supplied to the mixed water tank into pure water or acidic water. Specifically, when supplying pure water, an ion-exchange water treatment device in which a cation exchanger and an anion exchanger are mixed. When supplying acidic water, ion-exchange water using only a cation exchanger. A processing device has been proposed. In the case of supplying pure water, it has been proposed that the pure water itself does not have an effect of suppressing the growth of microorganisms, so that a heat sterilizer is also provided in the makeup water path.

JP-A-9-306523

  However, in the conventional configuration, it is necessary to introduce city water from the outside of the system in order to suppress the growth of microorganisms in the recovered water. The use of excess city water increases the running cost and reduces resource consumption. Productivity in terms of saving will be greatly reduced. In addition, since an additional water treatment device for converting city water into pure water or acidic water is required, the price of the system also increases. Since this water treatment apparatus needs to be periodically replaced, there is a problem that the running cost for operating the fuel cell system is further increased and an extra maintenance cost is generated.

  The present invention solves the above-mentioned conventional problems, and supplies pure water without adding city water from outside the system and without adding a water treatment device for converting the city water into pure water or acidic water. An object of the present invention is to provide a fuel cell system that suppresses the growth of microorganisms on the path and does not hinder power generation operation.

  In order to solve the conventional problem, the fuel cell system of the present invention stores combustion exhaust gas condensed water collected by condensing moisture in combustion exhaust gas of a hydrogen generator in a combustion exhaust gas condensed water tank, and stops power generation. Combustion exhaust gas condensed water supply means for supplying the combustion exhaust gas condensed water to the pure water supply path between the condensed water tank and the ion removing device is provided.

  Here, general growth conditions for microorganisms will be described.

  Regarding the relationship between the growth of microorganisms and the pH of water, general microorganisms tend to grow most easily in the range of neutral to weakly acidic (pH 6-7), and growth is suppressed when the pH value becomes smaller than this. It is done. In addition, as for the water flow state and the growth of microorganisms, when water is flowing, it is difficult to form large aggregates, so it is difficult for filters and parts in the water path to be clogged immediately. When the flow of water is small, microorganisms are relatively easy to grow and also become aggregates, so clogging of filters and the like is likely to occur. From the viewpoint of the fuel cell system, when power generation is stopped and there is no flow of water, the proliferation of microorganisms that cause blockage of components such as filters is likely to occur.

Moreover, the acidity degree of the condensed water collect | recovered within a fuel cell system is demonstrated easily. The condensed water recovered in the fuel cell system includes anode offgas condensed water recovered from the anode offgas, cathode offgas condensed water recovered from the cathode offgas, and combustion exhaust gas condensed water recovered from the combustion exhaust gas of the hydrogen generator. is there. Since all are so-called distilled water, a chlorine component having a bactericidal effect is not included. The anode off-gas condensed water and the cathode off-gas condensed water are substantially neutral water having a pH of 6-7. On the other hand, the flue gas condensate is a relatively acidic water having a pH of about 3 to 5. This is because CO2 is generated as a reaction byproduct when the fuel gas is converted to the hydrogen-rich reformed gas, and this gas is dissolved in water in the form of carbonate ions. For this reason, by storing combustion exhaust gas condensed water, it is possible to generate and store acidic water in the fuel cell system without introducing city water from the outside.

  That is, a necessary amount of acidic combustion exhaust gas condensate is stored during power generation of the fuel cell system, and when the power generation stops, the combustion exhaust gas condensate is supplied to a path through which microorganisms can easily propagate, thereby It is possible to suppress the growth of microorganisms in the water path of the system. In particular, by supplying this acidic water to the pure water supply path between the ion removal equipment from the condensed water tank where microorganisms and nutrients are easy to exist in the temperature condition where the microorganisms are easy to grow in the water path in the system, it becomes more prominent. The effect can be obtained.

  According to the fuel cell system of the present invention, microorganisms grow in the pure water supply path between the condensed water tank and the ion removal device when power generation is stopped, without providing water from the outside of the system or an additional acidic water generating device. Since it is possible to supply difficult acidic water, it is possible to prevent the clogging of filters, parts and piping in the water path, and to stably operate the fuel cell system.

1 is a configuration diagram of a fuel cell system according to Embodiment 1 of the present invention. Configuration diagram of a fuel cell system according to Embodiment 2 of the present invention Configuration diagram of fuel cell system according to Embodiment 3 of the present invention Configuration diagram of fuel cell system according to Embodiment 4 of the present invention Configuration diagram of fuel cell system according to Embodiment 5 of the present invention Configuration diagram of fuel cell system in Embodiment 6 of the present invention Configuration diagram of conventional fuel cell system

  A first invention is a hydrogen generator that generates hydrogen-rich reformed gas from fuel gas and water, and a fuel cell that generates electric power using the reformed gas supplied to the anode and air supplied to the cathode. And a pure water tank for storing pure water to be supplied to the hydrogen generator and the fuel cell, and a combustion exhaust gas condensed water for storing a combustion exhaust gas condensed water recovered by condensing moisture in the combustion exhaust gas of the hydrogen generator Tank, anode off-gas condensed water in which moisture in the anode off-gas discharged from the anode electrode of the fuel cell is condensed, and cathode off-gas condensed water in which moisture in the cathode off-gas discharged from the cathode electrode of the fuel cell is condensed A deionized water tank, an organic substance removing device and an ion removing device in the middle, and pure water for supplying the water stored in the condensed water tank to the deionized water tank And a combustion exhaust gas condensed water supply means for supplying the combustion exhaust gas condensed water of the combustion exhaust gas condensed water tank to the pure water supply path between the condensed water tank and the ion removing device when power generation is stopped. .

  In a second aspect of the invention, in particular, in the first aspect of the invention, the combustion exhaust gas condensed water supplied to the pure water supply path between the condensed water tank and the ion removing device is converted into the pure water before power generation operation. Combustion exhaust gas condensed water discharging means for discharging outside the supply path was provided.

According to a third aspect of the present invention, there is provided a hydrogen generator that generates a hydrogen-rich reformed gas from fuel gas and water, and a fuel cell that generates electric power using the reformed gas supplied to the anode electrode and air supplied to the cathode electrode. And a pure water tank for storing pure water to be supplied to the hydrogen generator and the fuel cell, and a combustion exhaust gas condensed water for storing the combustion exhaust gas condensed water recovered by condensing moisture in the combustion exhaust gas of the hydrogen generator Tank, anode off-gas condensed water in which moisture in the anode off-gas discharged from the anode electrode of the fuel cell is condensed, and cathode off-gas condensed water in which moisture in the cathode off-gas discharged from the cathode electrode of the fuel cell is condensed A condensed water tank for storing water, a water purification means for purifying water from the condensed water tank, and the water purification means provided in the middle and stored in the condensed water tank Wherein a pure water tank for supplying pure water supply path, and a combustion exhaust gas condensed water supplying means for supplying the combustion exhaust gas condensed water to the condensed water tank of the combustion exhaust gas condensed water tank when the power generation stop.

  In a fourth aspect of the invention, in particular, in the second aspect of the invention, the water purification means converts the organic matter removing device for removing organic matter of water from the condensed water tank, and the water that has passed through the organic matter removing device to pure water. The deaerator is connected to the pure water supply path between the organic substance remover and the ion remover via a flow switching valve, and the other end is the deaerator. A pure water circulation path connected to the apparatus, and the water in the condensed water tank passes through the pure water supply path, the flow path switching valve, the water circulation path, and the deaeration device before the power generation operation. Circulation recovery means for circulating recovery in the tank is provided.

  According to a fifth aspect of the invention, in particular, in any one of the first to fourth aspects of the invention, the flue gas condensed water supply for supplying the flue gas condensed water in the flue gas condensed water tank to the cathode offgas path when power generation is stopped. Have means.

  According to a sixth aspect of the present invention, in particular, in any one of the first to fifth aspects, when there is not a sufficient amount of condensed water in the condensed water tank, water in the combustion exhaust gas condensed water tank is degassed. Condensed water supply means for processing and supplying the condensed water tank is provided.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
FIG. 1 is a configuration diagram of a fuel cell system according to Embodiment 1 of the present invention. In FIG. 1, the fuel gas introduced from the outside of the system is reformed into a hydrogen-rich reformed gas by the hydrogen generator 1 and supplied to the anode electrode of the fuel cell 2. On the other hand, the air introduced from the outside of the system by the air supply pump 3 is humidified to an appropriate dew point by the humidifier 4 and then supplied to the cathode electrode of the fuel cell 2.

  The anode off-gas discharged from the anode electrode of the fuel cell 2 is separated from the anode off-gas condensed water generated by passing through the anode off-gas condenser 5 by the gas-liquid separator 7, and is then used as one of the combustion gases of the hydrogen generator 1. Supplied as a part. The separated anode off-gas condensed water is collected in the condensed water tank 8. On the other hand, the cathode offgas discharged from the cathode electrode of the fuel cell 2 is separated from the cathode offgas condensed water by the cathode offgas condenser 6 and then discharged to the outside of the system. The separated cathode off-gas condensed water is collected in the condensed water tank 8.

  Further, the combustion exhaust gas discharged from the hydrogen generator 1 is discharged to the outside of the system after separating the combustion exhaust gas condensed water by the combustion exhaust gas condenser 9. The separated flue gas condensed water is recovered in the flue gas condensed water tank 10.

  The water collected in the condensed water tank 8 is passed through a pure water supply path 14 provided with a condensed water supply valve 11, an organic substance removing device 13a, and an ion removing device 13b on the way by a pure water supply pump 12 to obtain pure water. Then, it is stored in the pure water tank 15. Here, the organic substance removing device 13a was filled with activated carbon, and the ion removing device 13b was filled with an ion exchange resin mixed with a cation resin and an anion resin. Further, a pure water supply pump filter 12a is integrally attached to the pure water supply pump 12 to prevent clogging of the pump itself.

  The pure water stored in the pure water tank 15 is circulated and supplied as cooling water to the fuel cell 2 by the cooling water circulation pump 16 to cool and recover the fuel cell. A part of this cooling water is supplied to the humidifier 4 and used for humidifying the air supplied to the cathode electrode of the fuel cell 2.

  The pure water stored in the pure water tank 15 is supplied as reforming water to the hydrogen generator 1 by the reforming water supply pump 17.

  The flue gas condensed water tank 10 is connected to a pure water supply path between the condensed water supply valve 11 and the pure water supply pump 12 by a flue gas condensed water supply path 19 having a flue gas condensed water supply valve 18 disposed in the middle. When the power generation of the fuel cell system is stopped, the condensed water supply valve 11 is closed, the combustion exhaust gas condensed water supply valve 18 is opened, and the pure water supply pump 12 is operated for a predetermined time, whereby the combustion exhaust gas condensed water is supplied to the pure water supply path 14. A predetermined amount is filled.

  The operation of the entire fuel cell system is controlled by the control device 20.

  With this configuration, when power generation is stopped, microorganisms grow from the condensed water tank in which the microorganisms are most likely to grow in the water path in the fuel cell system to the pure water supply path between the ion removal devices. Since it is possible to supply difficult acidic water, it is possible to stably operate the fuel cell system without clogging of parts in the path such as a filter due to the growth of microorganisms.

(Embodiment 2)
FIG. 2 is a configuration diagram of the fuel cell system according to Embodiment 2 of the present invention. Since the configuration of FIG. 2 is basically the same as the configuration of FIG. 1, only differences from FIG.

  In FIG. 2, a pipe branched from between the organic substance removing device 13a and the ion removing device 13b in the pure water supply path 14 is added, and a drain valve 21 is installed in the pipe.

  With this configuration, when power generation is stopped, the pure water supply path 14 is filled with a predetermined amount of combustion exhaust gas condensate having a low pH when the power generation is stopped, and the drain valve 21 is set to a predetermined level before restarting power generation. By opening the valve for a period of time, the acidic water staying in the pure water supply path 14 can be drained and replaced with water in the condensed water tank 8 that is close to neutrality. That is, since the water containing carbonate ions staying in the pure water supply path 14 during the stoppage of power generation can be discharged out of the path, the load on the ion removal device in the subsequent stage can be reduced.

(Embodiment 3)
FIG. 3 is a configuration diagram of the fuel cell system according to Embodiment 3 of the present invention. Since the configuration of FIG. 3 is basically the same as the configuration of FIG. 1, only the differences from FIG.

  In FIG. 3, the water level detection means 22 is installed inside the condensed water tank 8 so that the water level in the condensed water tank can be detected. Further, a condensate tank filter 23 was installed in the condensate tank in order to prevent blockage of piping and parts in the pure water supply path 14.

  In addition, the flue gas condensed water supply path 19 extending from the flue gas condensed water tank 10 was directly connected to the condensed water tank 8.

  By adopting such a configuration, combustion exhaust gas condensed water having a low pH can be supplied also to the condensed water tank 8 when power generation is stopped, so that the water level detection means 22 or the condensed water tank filter installed in the condensed water tank. Thus, problems such as blockage and malfunction due to the growth of microorganisms at 23 can be prevented.

(Embodiment 4)
FIG. 4 is a configuration diagram of a fuel cell system according to Embodiment 4 of the present invention. Since the configuration of FIG. 4 is basically the same as the configuration of FIG. 3, only differences from FIG. 3 will be described.

  In FIG. 4, a flow path switching valve 24 is provided between the organic substance removing device 13 a and the ion removing device 13 b, and a pure water circulation path 25 branched from here is provided above the deaerator 26 installed at the upper portion of the condensed water tank 8. Connected. In the deaerator 26, the air branched from the air pump 3 is introduced in a flow that opposes the flow of water.

  By adopting such a configuration, the acidic water retained in the condensed water tank 8 and the pure water supply path 14 during the power generation stop is introduced into the degassing device 26, thereby degassing the carbonate ions in the acidic water. I can do it. A specific operation of this process will be described. Due to the operation when power generation is stopped, acidic water as combustion exhaust gas condensate remains in the condensed water tank 8 and the pure water supply path 14. At the start of the next operation, the pure water supply pump 12 is operated after the flow path switching valve 24 is switched to the pure water circulation path 25 side before the start of power generation. At this time, the air supply pump 3 is also operated to guide the air introduced from the outside to the deaerator 26 by operating the switching valve. By continuing this state for a while, the carbonate ions contained in the acidic water staying in the condensed water tank 8 and the pure water supply path 14 are degassed and become neutral region water. If the flow switching valve 24 is switched to the ion removing device after such an operation to send water, the system can be operated without maintenance for a long time without applying an extra load to the ion removing device. I can do it. Here, the circulation time of the staying acidic water for deaeration can be arbitrarily set as the time until the pH of the water returns to a desired value. In addition, although the piping is separated and introduced immediately after the air supply pump 3 as the acid water deaeration air, it can be introduced from the cathode offgas piping connected to the condensed water tank 8 through the cathode electrode in terms of system operation. If so, parts and piping can be reduced by doing so.

(Embodiment 5)
FIG. 5 is a configuration diagram of a fuel cell system according to Embodiment 5 of the present invention. Since the configuration of FIG. 5 is basically the same as that of FIGS. 3 and 4, only different points will be described.

  In FIG. 5, a combustion exhaust gas supply path connected from the combustion exhaust gas condensed water tank 10 is connected to a cathode offgas path.

  With such a configuration, the acidic water stored in the combustion exhaust gas condensed water tank when power generation is stopped can be supplied to the path through which the condensed water of the cathode off gas flows.

Among the condensed water collected in the fuel cell system, the cathode off-gas condensed water is in a situation where microorganisms are more likely to propagate than the other anode off-gas condensed water and combustion exhaust gas condensed water. In the anode off-gas route, the combustion gas also flows, so that the piping and parts are made of metal such as stainless steel, and the total organic carbon (hereinafter referred to as TOC) component serving as a nutrient source for microorganisms is small. Further, since the flue gas condensate is acidic water, it is basically difficult for microorganisms to propagate. On the other hand, since the temperature of the entire cathode off-gas route is not so high and combustion gas does not flow, resin parts are often used for cost reduction. Therefore, the TOC component that is a nutrient source for microorganisms is easily contained. In addition, since the air in the cathode passage is also flowing, oxygen is also abundantly supplied. That is, since the moisture, moderate temperature, and nutrient sources necessary for the growth of microorganisms are provided, the conditions are such that the microorganisms can easily grow. Therefore, by adopting a configuration like this embodiment, combustion exhaust gas condensate can be supplied to this path when power generation is stopped, and growth in a part where microorganisms are likely to grow can be suppressed. It is also effective. In particular, when there is a portion that stays in the piping due to the layout of the system, the effect can be further improved by supplying it from the front.

(Embodiment 6)
FIG. 6 is a configuration diagram of a fuel cell system according to Embodiment 6 of the present invention. Since the configuration of FIG. 6 is basically the same as that of FIGS. 4 and 5, only different points will be described.

  In FIG. 6, a combustion exhaust gas condensed water supply path 19 connected from the combustion exhaust gas condensed water tank 10 is connected to an upper portion of a deaeration device 26 installed on the condensed water tank 8. Here, a cathode off gas was used as the gas to be opposed in the deaerator 26.

  When the water level detected by the water level detecting means installed in the condensate tank decreases, the flue gas condensed water supply valve 18 is opened to supply the flue gas condensed water to the condensate water tank 8. At this time, since the flue gas condensed water passes through the deaerator 26, the carbonate ions contained therein are deaerated to become water in the neutral region. Therefore, the system can be operated without increasing the load of the ion removal device in the subsequent stage. It becomes. Further, when power generation is stopped, the required amount of combustion exhaust gas condensed water can be supplied to the pure water supply path 14 and the condensed water tank 8. In addition, when supplying combustion exhaust gas condensate to the condensate tank 8 when power generation is stopped, it is possible to supply as acidic water having an effect of suppressing the growth of microorganisms by stopping the counter air in the deaerator 26. It is. In addition, when power generation is resumed, the subsequent stage ion removal is performed by circulating acidic water staying in the condensed water tank 8 and the deionized water supply path 14 through the path including the deaerator 26 in the same manner as in the fifth embodiment before starting the power generation. The system can be operated without increasing the load on the device.

  The fuel cell system according to the present invention can suppress the growth of microorganisms in the condensed water path when power generation is stopped, so that the system can be stably operated without clogging parts and water piping in the condensed water path. It becomes possible. Accordingly, it is possible to provide a fuel cell system that can be operated without maintenance for a long period of time.

DESCRIPTION OF SYMBOLS 1 Hydrogen generator 2 Fuel cell 8 Condensate water tank 10 Combustion exhaust gas condensate water tank 13 Water purification device 13a Organic substance removal device 13b Ion removal device 14 Pure water supply path 15 Pure water tank 24 Flow path switching valve 25 Pure water circulation path 26 Desorption Equipment

Claims (6)

A hydrogen generator that generates hydrogen-rich reformed gas from fuel gas and water, a fuel cell that generates power using the reformed gas supplied to the anode and air supplied to the cathode, and the hydrogen generator And a pure water tank for storing pure water to be supplied to the fuel cell, a combustion exhaust gas condensed water tank for storing combustion exhaust gas condensed water recovered by condensing moisture in the combustion exhaust gas of the hydrogen generator, and the fuel cell A condensed water tank for storing anode off-gas condensed water obtained by condensing moisture in anode off-gas discharged from the anode electrode and cathode off-gas condensed water obtained by condensing moisture contained in cathode off-gas discharged from the cathode electrode of the fuel cell A deionized water supply path for supplying the deionized water tank with water stored in the condensate tank, provided with an organic substance removing device and an ion removing device in the middle; Fuel cell system having a combustion exhaust gas condensed water supplying means for supplying the pure water supply path between the condensed water tank the combustion exhaust gas condensed water of the combustion exhaust gas condensed water tank when stopping said ion removal device. Combustion exhaust gas condensed water discharging means for discharging the combustion exhaust gas condensed water supplied to the pure water supply path between the condensed water tank and the ion removing device to the outside of the pure water supply path before power generation operation. The fuel cell system according to claim 1 provided. A hydrogen generator that generates hydrogen-rich reformed gas from fuel gas and water, a fuel cell that generates power using the reformed gas supplied to the anode and air supplied to the cathode, and the hydrogen generator And a pure water tank for storing pure water to be supplied to the fuel cell, a combustion exhaust gas condensed water tank for storing combustion exhaust gas condensed water recovered by condensing moisture in the combustion exhaust gas of the hydrogen generator, and the fuel cell A condensed water tank for storing anode off-gas condensed water obtained by condensing moisture in anode off-gas discharged from the anode electrode and cathode off-gas condensed water obtained by condensing moisture contained in cathode off-gas discharged from the cathode electrode of the fuel cell Water purification means for purifying water from the condensed water tank, and water stored in the condensed water tank provided with the water purification means in the middle. Fuel cell system having a pure water supply path for supplying to the click, and a combustion exhaust gas condensed water supplying means for supplying the combustion exhaust gas condensed water to the condensed water tank of the combustion exhaust gas condensed water tank when the power generation is stopped. The water purification means comprises an organic substance removing device that removes organic substances of water from the condensed water tank, and an ion removing device for making the water that has passed through the organic substance removing device pure water, a deaeration device, A pure water circulation path having one end connected to the pure water supply path between the organic substance removing apparatus and the ion removing apparatus via a flow path switching valve and the other end connected to the deaerator. 4. Circulating and collecting means for circulating and collecting water in the condensed water tank before operation through the pure water supply path, the flow path switching valve, the water circulation path, and the deaeration device. The fuel cell system described. The fuel cell system according to any one of claims 1 to 4, further comprising combustion exhaust gas condensed water supply means for supplying the combustion exhaust gas condensed water of the combustion exhaust gas condensed water tank to the cathode off-gas path when power generation is stopped. 2. The apparatus according to claim 1, further comprising condensed water replenishing means for degassing the water in the combustion exhaust gas condensed water tank and supplying the condensed water tank to the condensed water tank when there is not a sufficient amount of condensed water in the condensed water tank. 6. The fuel cell system according to any one of items 5.

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