JP2012028159A - Fuel cell system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel cell system in which an antibacterial action is exerted on active carbon with an anti-fungus agent not fastened to the active carbon.SOLUTION: A cell system 100 is provided with a fuel cell 1, a water use equipment for using recycled water recycled from exhaust gas discharged from the fuel cell 1, and a first water passage 30 for supplying recycled water to the water use equipment. The first water passage 30 is provided with a first water tank 5 for storing recycled water, a purifier 6 with active carbon 12 installed in the downstream side of the first water tank 5, a water sender 7 for sending out recycled water in the first water tank 5 to the water use equipment, and an anti-fungus agent 15 installed upstream compared to the active carbon 12.

Description

  The present invention relates to a fuel cell system.

  A fuel cell converts chemical energy into electrical energy through a direct reaction between hydrogen and oxygen, is a power generation device that is environmentally friendly because it has high power generation efficiency and emits almost no air pollutants. Further, since heat is generated simultaneously with power generation, a cogeneration system can be constructed by collecting this heat, and the total energy efficiency can be increased to 70% to 80%. For this reason, fuel cells are expected as a technology that can contribute to the prevention of global warming.

  A hydrogen-containing gas (a gas containing hydrogen as a main component) used as a fuel for a fuel cell is obtained by reacting (reforming reaction) a hydrocarbon-based source gas such as city gas with water in a hydrogen generator, for example. It is done. In general, a catalyst is used in the hydrogen generator in order to efficiently generate hydrogen.

  In the hydrogen generator, if the water (reformed water) used for the reforming reaction contains impurities such as metal ions, the performance of the catalyst used in the hydrogen generator may be reduced. Moreover, this impurity may adhere inside a hydrogen generator, and may reduce hydrogen production performance. For this reason, it is necessary to supply water from which impurities such as metal ions have been removed to the hydrogen generator as reformed water.

  On the other hand, in order for the fuel cell to generate power efficiently, it is necessary to cool the fuel cell body during the power generation operation. In many cases, water (cooling water) is used for cooling. At this time, if the conductivity of the cooling water is high, there is a possibility of causing electric leakage. Therefore, it is preferable to reduce the conductivity of the cooling water by removing the ionic component contained in the cooling water.

  Therefore, in a fuel cell system equipped with a fuel cell and a hydrogen generator, water after impurities have been removed through various filters, ion exchange resins, etc., is usually supplied to the hydrogen generator for use in the reforming reaction, Used for cooling the fuel cell.

  Water generated by power generation of the fuel cell can be used as water used for generating hydrogen or cooling the fuel cell. Water generated by power generation is condensed and recovered by cooling the exhaust gas discharged from the air electrode during power generation. Condensed / recovered water (hereinafter referred to as “recovered water”) contains a trace amount of organic matter and its water temperature is often less than 40 ° C., and is therefore in a state suitable for the propagation of bacteria. Therefore, if mold or fungi enter the recovered water from the water introduced from outside the system or the exhaust port that discharges the air (exhaust gas) after the water is recovered, these will propagate through the recovery water path and be recovered. It may cause problems such as blockage of the water path.

  On the other hand, it has been proposed to perform antibacterial recovery water using an antibacterial agent. For example, Patent Document 1 proposes arranging an ultraviolet antibacterial device and an antibacterial filter in a flow path of mixed water containing recovered water and tap water. In addition, as an antibacterial filter, it is described that a filling tank in which a metal film having an antibacterial action is attached to the surface of a granular absorbent (activated carbon) is described.

  Patent Document 2 proposes that an antibacterial agent is disposed above the ion exchange resin in the gravity direction in a pure water purifier for purifying recovered water. Specifically, it is described that a pure water device is filled with granular activated carbon to which fine particles such as metal having antibacterial activity are fixed.

JP-A-9-63612 JP 2010-33917 A

  In Patent Documents 1 and 2, particles in which a substance such as a metal having an antibacterial action (antibacterial agent) is fixed on the surface of granular activated carbon are used. However, the production process of particles containing such antibacterial agents is complicated.

  This invention is made | formed in view of the said situation, The objective is to provide the fuel cell system which exhibits an antimicrobial effect with respect to activated carbon, without making an antimicrobial agent adhere to the surface of activated carbon.

  The fuel cell system of the present invention includes a fuel cell, a water use device that uses recovered water recovered from the exhaust gas discharged from the fuel cell, and a first for supplying the recovered water to the water use device. A water path, a first water tank provided in the first water path for storing the recovered water, and in the first water path, provided on the downstream side of the first water tank and having activated carbon. A purifier, a water delivery device provided in the first water path for delivering the recovered water in the first water tank to the water utilization device, and the activated carbon in the first water path. And an antibacterial agent provided upstream.

  In a preferred embodiment, the fuel cell system further includes a filter provided downstream of the antibacterial agent in the first water path.

  In a preferred embodiment, the filter is disposed in the purifier near the end face on the downstream side of the activated carbon.

  In a preferred embodiment, the activated carbon and the antibacterial agent are disposed in the same container in the order of the activated carbon and the antibacterial agent from above in the direction of gravity.

  The upstream end surface of the activated carbon may be in contact with the antibacterial agent.

  In a preferred embodiment, the first water path further comprises an ion exchanger provided on the downstream side of the filter, and the ion exchanger, the filter, the activated carbon, and the antibacterial agent from above in the direction of gravity. They are arranged in order.

  The ion exchanger may be supported by the filter.

  In a preferred embodiment, the fuel cell system has a plurality of particles or pellets containing the antibacterial agent, and the plurality of particles or pellets are contained in a container that passes water.

  In a preferred embodiment, the antibacterial agent is configured such that the amount of the antibacterial component eluted from the antibacterial agent into water increases after the power generation operation is stopped than during the power generation operation of the fuel cell system.

  The antibacterial agent is provided in the first water tank, and is immersed in the water in the first water tank after the power generation operation is stopped rather than during the power generation operation of the fuel cell system. You may be comprised so that the volume of the part which is carrying out may increase.

  In a preferred embodiment, during the power generation operation of the fuel cell system, the water level of the first water tank is maintained below a lower limit water level at which the entire antibacterial agent is immersed in water in the first water tank. The water level controller further increases the water level of the first water tank after the power generation operation is stopped than during the power generation operation.

  In a preferred embodiment, the fuel cell system includes a second water tank, a second water path connecting the first water tank and the second water tank, and the second water path. And an operation of the valve is controlled by the water level controller.

  In a preferred embodiment, the first water tank is made of a material containing the antibacterial agent.

  The antibacterial agent may include a silver antibacterial agent.

  The antibacterial agent may be configured such that the antibacterial component elutes in the collected water in the range of 10 μg / L to 100 μg / L.

  According to the present invention, since the antibacterial agent is disposed on the upstream side of the activated carbon, the antibacterial component eluted in the water rides on the flow of water and is supplied to the activated carbon. Therefore, the antibacterial action can be exerted on the activated carbon without attaching the antibacterial agent to the activated carbon as in the prior art.

It is a figure which shows the structure of the fuel cell system of 1st Embodiment by this invention. (A) is a typical expanded sectional view of the purifier in the embodiment of the present invention, and (b) is an enlarged sectional view of the purifier of the reference example in which the antibacterial agent is arranged on the downstream side of the activated carbon. . It is a figure which shows the structure of the fuel cell system of 2nd Embodiment by this invention. It is a figure which shows the structure of the fuel cell system of 3rd Embodiment by this invention. (A) And (b) is an expanded sectional view which illustrates the water level of the recovered water 14 after a power generation operation, (c) is a power generation operation stop. It is a figure which shows the structure of the fuel cell system of 4th Embodiment by this invention.

(First embodiment)
Hereinafter, a fuel cell system according to a first embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a diagram showing the configuration of the fuel cell system of the present embodiment.

  The fuel cell system 100 includes a fuel cell 1, a condenser 10 that condenses and recovers water from exhaust gas discharged from the fuel cell 1, and a water utilization device (not shown) that uses the recovered water (recovered water). ) And a water path 30 for supplying the recovered water to the water-using device.

  The water path 30 has a recovered water tank (also referred to as a “first water tank”) 5 for storing recovered water, a purifier 6 provided on the downstream side of the recovered water tank 5 for purifying the recovered water, A water delivery device 7 for sending the collected water in the collected water tank 5 to a water-utilizing device, and an antibacterial agent 15 that suppresses the growth of mold and fungi in the collected water are provided. The purifier 6 has activated carbon 12. The activated carbon 12 adsorbs and removes organic substances and chlorine contained in the recovered water. The form of the activated carbon 12 is arbitrary, but for example, a form that has a predetermined thickness with respect to the flow of recovered water and that is configured to form a substantially flat surface on the upstream side and the downstream side is preferable. Specifically, a form in which an activated carbon layer is formed by filling activated carbon particles in a cylindrical container, or a form using a flat activated carbon fiber filter or the like is exemplified.

  The antibacterial agent 15 is disposed upstream of the activated carbon 12 in the water path 30. The antibacterial agent 15 may be disposed in the pipe of the water passage 30, or may be disposed in the purifier 6 or the recovered water tank 5. When the antibacterial agent (for example, silver-based antibacterial agent) 15 comes into contact with the recovered water, the antibacterial component (for example, silver ions) is eluted in the recovered water and exhibits an antibacterial action. By disposing the antibacterial agent 15 on the upstream side of the activated carbon 12, it is possible to efficiently suppress the growth of fungi and fungi on the activated carbon 12, as will be described in detail later. Therefore, blockage of the water path 30 caused by mold and fungi can be suppressed.

  In the present embodiment, the purifier 6 has an ion exchanger 13 such as an ion exchange resin on the downstream side of the activated carbon 12. Thereby, the antibacterial component (for example, silver ion) eluted from the antibacterial agent 15 into the recovered water can be removed from the recovered water before being supplied to the water-using device.

  Further, the filter 11 is disposed in the water path 30 downstream of the activated carbon 12. The filter 11 is preferably disposed on the downstream side (water utilization device side) of the antibacterial agent 15. When arranged in this way, part of the antibacterial component that has passed through the activated carbon 12 is captured by the filter 11 and exhibits an antibacterial action in the vicinity of the filter 11, so that clogging of the filter 11 is further effectively suppressed.

  The operation of the fuel cell system 100 will be briefly described.

  First, a gas mainly containing air (hereinafter, simply referred to as “hydrogen-containing gas”) is supplied to the air electrode (cathode electrode) of the fuel cell 1 and the fuel electrode (anode electrode). In the fuel cell 1, oxygen in the air and hydrogen in the hydrogen-containing gas react to generate power. Thereby, a gas containing water generated by power generation (hereinafter referred to as “exhaust gas”) is discharged from the cathode electrode of the fuel cell 1. A gas containing hydrogen remaining without reacting with oxygen (hereinafter referred to as “hydrogen off-gas”) is discharged from the anode electrode.

  The exhaust gas of the fuel cell 1 is sent to the condenser 10, where water contained in the exhaust gas is condensed. The condensed water (recovered water) is stored in the recovered water tank 5. The water in the recovered water tank 5 is appropriately sent to the water utilization device by the water path 30. In the example shown in FIG. 1, the recovered water flowing through the water passage 30 is supplied to the water utilization device through the purifier 6 having the activated carbon 12 after contacting the antibacterial agent 15.

  Although a water utilization apparatus is not specifically limited, When using recovered water as a cooling water which cools a fuel cell, the cooling water supply apparatus containing a cooling water path, a cooling water tank, etc. corresponds to a water utilization apparatus. Further, in the hydrogen generator, when the hydrogen generator is used as reformed water to be reacted with the hydrocarbon-based source gas, the hydrogen generator corresponds to a water-using device. The recovered water may be used for both cooling water and reforming water. In that case, the water utilization device includes a cooling water supply device and a hydrogen generator.

  As a result of studies by the present inventors, when activated carbon is provided to purify recovered water in a conventional fuel cell system, when the fuel cell system is stopped for a long time (for example, for one month), mold or the like is generated in the activated carbon during the stop. Found it easy to breed.

  On the other hand, in the fuel cell system 100 of this embodiment, since the antibacterial agent 15 is disposed upstream of the activated carbon 12, it is possible to efficiently prevent the growth of mold and the like on the activated carbon 12. Hereinafter, detailed description will be given with reference to the drawings.

  Fig.2 (a) is a typical expanded sectional view of the purifier 6 in this embodiment. In the purifier 6, the antibacterial component (for example, silver ions) 15 a of the antibacterial agent 15 is eluted into the recovered water and flows into the activated carbon 12 along the flow of the recovered water. For this reason, propagation of mold and fungi on the activated carbon 12 can be effectively suppressed. In addition, when a part of the antibacterial component 15a that has flowed in is adsorbed by the activated carbon and trapped by the activated carbon 12, even when the recovered water is not circulated particularly during the stop of the operation of the fuel cell system, the growth of mold and fungi on the activated carbon 12 Can be suppressed more effectively.

  On the other hand, when the antibacterial agent 15 is arranged on the downstream side of the activated carbon 12 as in the reference example shown in FIG. 2B, the antibacterial component 15a eluted from the antibacterial agent 15 flows along the flow of recovered water. Since it flows downstream, it is difficult to flow into the activated carbon 12. Therefore, the activated carbon 12 does not have a sufficient antibacterial effect, and there is a possibility that the growth of mold or the like on the activated carbon 12 cannot be sufficiently suppressed.

  Moreover, in this embodiment, as shown to Fig.2 (a), the filter 11 is arrange | positioned in the downstream of the activated carbon 12. As shown in FIG. Thereby, among the antibacterial components 15a eluted from the antibacterial agent 15, the antibacterial components 15a that have passed through the activated carbon 12 without being trapped by the activated carbon 12 pass through the filter 11 together with the recovered water. At this time, a part of the antibacterial component 15 a can be captured by the filter 11. Accordingly, the blocking of the filter 11 can be suppressed by the antibacterial action of the antibacterial component 15a. Furthermore, when the ion exchanger 13 is disposed on the downstream side of the filter 11, for example, the amount of the antibacterial component 15a flowing into the ion exchanger 13 can be reduced, so that the burden on the ion exchanger 13 can be reduced.

  The water path 30 in the present embodiment is preferably configured so that the recovered water flows through the purifier 6 in the direction opposite to the direction of gravity. Thereby, in the purifier 6, the direction in which the bubbles rise and the direction in which the water flows are in the same direction, so that there is an advantage that the flow of water hardly bites the bubbles.

  The filter 11 is preferably disposed in the vicinity of the downstream end face of the activated carbon 12. Thereby, it is possible to prevent the bacteria from growing on the downstream end face of the activated carbon 12 by the antibacterial component 15a trapped in the filter 11. The “near the downstream end face of the activated carbon 12” here may be in a range where the antibacterial action of the antibacterial component 15 a trapped in the filter 11 reaches the downstream end face of the activated carbon 12.

  Thus, according to the present embodiment, the antimicrobial component 15a eluted from the antibacterial agent 15 and trapped by the activated carbon 12 or the filter 11 can more effectively suppress the growth of mold and fungi on the activated carbon 12. Therefore, unlike Patent Documents 1 and 2, it is not necessary to fix the antibacterial agent to the surface of the activated carbon particles, so that the manufacturing process can be simplified and the manufacturing cost can be reduced.

  The antibacterial agent 15 may be disposed in the water path 30 on the upstream side of the activated carbon 12, but is preferably disposed in the recovered water tank 5 or in the water path 30 on the downstream side of the recovered water tank 5. Accordingly, even when the recovered water that has been retained in the recovered water tank 5 for a long time is supplied to the water-using device, it is possible to suppress the blockage of the water path 30 due to the mold or fungi of the recovered water.

  Further, the antibacterial agent 15 may be provided in the same container as the activated carbon 12. In this case, it is preferable that the activated carbon 12 and the antibacterial agent 15 are provided in this order from above in the same container. Thereby, since the upstream end surface of the activated carbon 12 and the antibacterial agent 15 contact | connect, the fall of the antibacterial action of the upstream end surface of the activated carbon 12 can be suppressed.

  Further, when the ion exchanger 13, the filter 11, the activated carbon 12, and the antibacterial agent 15 are provided in this order from above, the filter 11 not only has a function of trapping the antibacterial component 15a but also serves as a support for the ion exchanger 13. Can also function.

  In this embodiment, although it does not specifically limit as the antibacterial agent 15, For example, the metal which has antibacterial effects, such as silver, copper, zinc, can be used. A silver compound such as a silver complex is preferably used. Moreover, you may use organic type and inorganic antibacterial agents other than a metal. Further, the shape of the antibacterial agent 15 is not particularly limited. For example, particles containing antibacterial agents (hereinafter referred to as “antibacterial agent particles”) or pellets (antibacterial agent pellets) may be disposed in the water path 30. The antibacterial agent particles may be, for example, particles in which an antibacterial agent (such as Ag fine particles) is supported on a particulate ceramic. Further, the antibacterial agent pellet may be a pellet obtained by adding an antibacterial agent (silver fine particles or the like) to a resin material such as nylon. Alternatively, a filter containing the antibacterial agent 15 may be disposed.

  In the case of using a plurality of antibacterial agent pellets or a plurality of antibacterial agent particles, if these pellets or particles move from a predetermined arrangement position, various problems may be caused. For example, when the antibacterial agent pellet is disposed in the recovered water tank 5, the antibacterial agent pellet may move in the pipe from the recovered water tank 5 toward the purifier 6 along the flow of the recovered water, which may cause clogging of the pipe. is there. Further, for example, when an antibacterial agent pellet is disposed near the container opening of the purifier 6, the antibacterial agent pellet may spill outside from the container opening of the purifier 6 when the purifier 6 is attached to or removed from the system. There is. Therefore, it is preferable that the plurality of antibacterial agent pellets or the plurality of antibacterial agent particles are accommodated in a container capable of passing water. Thereby, it can prevent that an antimicrobial agent pellet and an antimicrobial agent particle move from the predetermined position arrange | positioned at the time of system construction. The said container may be comprised, for example with the polypropylene mesh.

  Moreover, instead of disposing the antibacterial agent 15, a part or the whole of a pipe provided in the water path 30, a recovered water tank, a filter, a container of the purifier 6, or the like may be made of a material containing the antibacterial agent. . Alternatively, an antibacterial agent may be applied to a part or the entire surface of the pipe or the container by surface processing.

(Second Embodiment)
FIG. 3 is a configuration diagram of the fuel cell system 200 according to the second embodiment of the present invention. In the present embodiment, the recovered water is configured to be used in the cooling water supplier and the hydrogen generator. In FIG. 3, the same components as those in FIG.

  The fuel cell system 200 includes a fuel cell 1, a condenser 10, a hydrogen generator 2 for generating a hydrogen-containing gas to be supplied to the fuel cell 1, a cooling water supplier 32 that cools the fuel cell 1, a fuel A water path 30 is provided for supplying the recovered water obtained by condensing the exhaust gas of the battery 1 to the hydrogen generator 2 and the cooling water supplier 32.

  The water path 30 is provided with a recovered water tank 5, a purifier 6 and a water delivery device 7. The purifier 6 in this embodiment has the same configuration as the purifier 6 shown in FIG. That is, the ion exchanger 13, the filter 11, the activated carbon 12, and the antibacterial agent 15 are arranged in this order from the top in the container of the purifier 6.

  The hydrogen generator 2 includes a reforming section (not shown) having a reforming catalyst and a combustion section 3 that heats the reforming section. In the reforming section, a hydrogen-containing gas mainly containing hydrogen is generated by a reforming reaction between the raw material (here, city gas) and water. The generated hydrogen-containing gas is supplied to the anode electrode of the fuel cell 1. In the reforming section, recovered water that has passed through the purifier 6 can be used as water (reformed water) to be reacted with the raw material. Further, the combustion unit 3 may combust off gas (hydrogen off gas) discharged from the anode electrode of the fuel cell 1. In order to reduce the carbon monoxide concentration in the hydrogen-containing gas generated in the reforming unit, a CO reduction unit may be provided downstream of the reforming unit with respect to the flow direction of the hydrogen-containing gas. Good. The CO reduction unit may include, for example, one or both of a shift unit having a shift catalyst and a CO removal unit having an oxidation catalyst or a methanation catalyst.

  The cooling water supplier 32 includes a cooling water tank 4, a cooling water path 34 for circulating the cooling water between the fuel cell 1 and the cooling water tank 4, a water feeder 8 provided in the cooling water path 34, a fuel And a heat converter 9 for radiating the cooling water before flowing into the battery 1. In the present embodiment, the recovered water after passing through the purifier 6 is sent to the cooling water tank 4. The water in the cooling water tank 4 is radiated by the heat exchanger 9 in the cooling water path 34 and then sent to a cooling water flow path (not shown) provided in the fuel cell 1 to cool the fuel cell 1. Thereafter, it is returned to the cooling water tank 4. Further, as shown in the figure, the cooling water tank 4 has an overflow water path for returning an excess amount of water to the recovered water tank 5 when the amount of water stored in the cooling water tank 4 exceeds a predetermined amount. 36 may be provided.

  In the present embodiment, a water path 40 is provided for supplying water to the reforming unit after the water stored in the cooling water tank 4 via the purifier 6 is radiated by the heat exchanger 9. Thereby, the recovered water in the cooling water tank 4 can be utilized as reforming water. In addition, you may return the water after thermally radiating with the heat exchanger 9 to the collection | recovery tank 5 with the water path 40. FIG.

  According to this embodiment, treatment of recovered water (antibacterial of recovered water, removal of impurities from recovered water, etc.) can be performed in the same manner as in the above-described embodiment (FIG. 1). The effect is obtained.

  In the present embodiment, impurities such as metal ions (including metal ions eluted from the antibacterial agent 15) are removed from the recovered water by the activated carbon 12, the filter 11, and the ion exchanger 13, and then supplied to the hydrogen generator 2. . Therefore, in the hydrogen generator 2, it can suppress that the catalyst performance of a reforming catalyst falls by an impurity. Moreover, the fall of the hydrogen production performance by an impurity adhering in the hydrogen generator 2 can be suppressed.

  Furthermore, since water whose conductivity has been reduced by removing the ionic component is used as cooling water, leakage during cooling of the fuel cell 1 body can be prevented.

  In this embodiment, the antibacterial agent 15 is disposed on the upstream side of the activated carbon 12 so as to be in contact with the activated carbon 12, but the position where the antibacterial agent 15 is disposed is not limited thereto. If the antibacterial agent 15 is disposed upstream of the activated carbon 12, in other words, between the condenser 10 and the activated carbon 12 in the water path 30, the effect of the present invention can be obtained.

  Preferably, the antibacterial agent 15 is disposed in the recovered water tank 5 or in the water path 30 between the recovered water tank 5 and the activated carbon 12. In the fuel cell system 200, the recovered water is held in the recovered water tank 5 or the like when the power generation operation is stopped. Thereafter, when the power generation operation is resumed, the water retained in the recovered water tank 5 is used as reforming water or cooling water. For this reason, when the antibacterial agent 15 is disposed at the above position, it is possible to more effectively suppress the water path 30 from being blocked by mold or fungi in the collected water that is retained when the power generation operation is resumed. Because.

(Third embodiment)
FIG. 4 is a configuration diagram of a fuel cell system 300 according to the third embodiment of the present invention. 3, the same components as those in FIGS. 1 and 3 are denoted by the same reference numerals, and the description thereof is omitted.

  In the present embodiment, the antibacterial agent 15 is disposed inside the recovered water tank 5. Moreover, it differs from the above-mentioned embodiment by the point which can control the quantity of the antibacterial component eluted to the collection | recovery water from the antibacterial agent 15 by changing the contact area of the antibacterial agent 15 and collection | recovery water.

  In the fuel cell system 300, the antibacterial agent 15 is disposed above the recovered water tank 5. Further, the recovered water tank 5 is provided with a level sensor 16, a solenoid valve 17, and a water level controller 18. The level sensor 16 detects the water level of the recovered water 14 in the recovered water tank 5. The solenoid valve 17 is connected to the water supply port of the recovered water tank 5. The water level controller 18 adjusts the water level in the recovered water tank 5 based on the water level detected by the level sensor 16. For example, when an operation for stopping the operation of the fuel cell system 300 is performed, the water level controller 18 opens the electromagnetic valve 17 and replenishes the recovered water tank 5 with water such as tap water from the outside of the system. Thereby, since the water level of the recovered water 14 in the recovered water tank 5 is increased and the volume of the portion of the antibacterial agent 15 that is immersed in the recovered water 14 is increased, a greater antibacterial effect is exhibited. In addition, by switching the water path 30 of the reforming water, the water in the cooling water tank 4 can be transferred to the recovered water tank 5 and the water level of the recovered water tank 5 can be raised.

  In the present embodiment, the water level controller 18 controls the water level of the recovered water 14 to be higher after the power generation operation is stopped than during the power generation operation of the fuel cell system 300. Thereby, after the power generation operation is stopped, the contact area between the antibacterial agent 15 and the recovered water 14 can be made larger than that during the power generation operation, so that the amount of antibacterial components eluted in the recovered water 14 can be increased. Therefore, it is possible to more effectively suppress the growth of fungi and fungi during the long-term system stoppage. On the other hand, during the power generation operation of the fuel cell system 300, the amount of antibacterial components (for example, silver ions) eluted into the recovered water 14 can be suppressed, so that the amount of antibacterial components to be removed by the ion exchanger 13 can be reduced. The burden on the ion exchanger 13 can be reduced.

  Next, an example of the water level in the recovered water tank 5 will be described with reference to the drawings. 5A and 5B are enlarged cross-sectional views illustrating the water level of the recovered water 14 after the power generation operation of the fuel cell system 300, and FIG.

  During the power generation operation of the fuel cell system 300, as shown in FIG. 5A, the water level L of the recovered water 14 is maintained below the lower limit water level Lx at which the entire antibacterial agent 15 is immersed in the recovered water 14. Thereby, since only a part of the antibacterial agent 15 is in contact with the recovered water 14, the elution amount of the antibacterial component from the antibacterial agent 15 to the recovered water 14 can be reduced. Therefore, the burden on the ion exchanger 13 can be reduced and deterioration can be suppressed.

  In addition, during the power generation operation, mold fungi hardly propagate compared to after the power generation operation is stopped. In general, during the power generation operation, water is supplied to the cooling water tank 4 more frequently than after the power generation operation is stopped, and water stays in the water path 30 compared to after the power generation operation is stopped. It is because it is suppressed. Therefore, as shown in FIG. 5B, the water level L may be controlled so that the recovered water 14 does not contact the antibacterial agent 15 during the power generation operation. Thereby, it becomes possible to elute the required amount of antibacterial components in the recovered water 14 only after the power generation operation is stopped while more effectively suppressing the deterioration of the ion exchanger 13.

  On the other hand, after the power generation operation is stopped, as shown in FIG. 5C, the water level L of the recovered water 14 is controlled so that the entire antibacterial agent 15 is immersed in the recovered water 14 (that is, above the lower limit water level Lx). Also good. Thereby, since the elution amount of the antibacterial component from the antibacterial agent 15 to the recovered water 14 can be increased, the antibacterial action can be expressed more effectively. Therefore, the blockage of the water passage 30 due to the growth of mold, fungi, etc. in the collected water can be suppressed particularly during the power generation operation stop.

  The water level of the recovered water 14 is not limited to the example shown in FIG. That is, after the power generation operation is stopped, the level of the recovered water 14 is raised above the water level during the power generation operation without recovering the entire antibacterial agent 15 to the water level immersed in the recovered water 14. By increasing the volume of the portion immersed in the water 14, the same effect as described above can be obtained.

  In this embodiment, the amount of the antibacterial component eluted from the antibacterial agent 15 is controlled by the relationship between the level of the recovered water 14 in the recovered water tank 5 and the position where the antibacterial agent 15 is disposed. You may control the elution amount of an antibacterial component. For example, by changing the position of the antibacterial agent 15 between the power generation operation and after the power generation operation is stopped, the volume of the portion of the antibacterial agent 15 that is immersed in the recovered water 14 is increased after the power generation operation is stopped. You may let them.

  Moreover, instead of disposing the antibacterial agent 15 in the recovered water tank 5, the recovered water tank 5 may be made of a material containing an antibacterial agent (such as silver). In this case, after the power generation operation is stopped, the contact area between the antibacterial agent and water can be increased by increasing the amount of water in the recovered water tank more than the amount of water during the power generation operation. It becomes possible.

(Fourth embodiment)
FIG. 6 is a configuration diagram of a fuel cell system 400 according to a fifth embodiment of the present invention. In FIG. 6, the same components as those in FIGS. 1, 3, and 4 are denoted by the same reference numerals, and description thereof is omitted.

  In the present embodiment, a reserve tank (also referred to as “second water tank”) 19, a reserve water path 38 for allowing water (reserve tank water) 20 in the reserve tank 19 to flow into the recovered water tank 5, and a reserve 3 and the fuel cell system 300 shown in FIG. 3 in that the electromagnetic valve 21 (electromagnetic valve 17 shown in FIG. 3) is not provided at the water supply port of the recovered water tank 5. Is different.

  It is preferable that the water surface of the reserve tank water 20 of the reserve tank 19 is configured to be higher than the antibacterial agent 15 disposed in the recovered water tank 5 during the power generation operation of the fuel cell system 400. Although not shown, for example, the reserve tank 19 may be disposed above the recovered water tank 5. Therefore, when the electromagnetic valve 21 is opened, the reserve tank water 20 is sent to the recovered water tank 5 through the reserve water path 38. The electromagnetic valve 21 is configured to be opened and closed by a water level controller 18.

  Thereby, during the power generation operation, the electromagnetic valve 21 is closed, the water level of the recovered water tank 5 is maintained below the lower limit water level Lx (FIG. 5) at which the entire antibacterial agent 15 is immersed in the condensed water 14, and after the power generation operation is stopped, By opening the electromagnetic valve 21, the reserve tank water 20 stored in the reserve tank 19 can be made to flow into the recovered water tank 5. As a result, since the water level of the recovered water tank 5 becomes higher after the power generation operation is stopped than during the power generation operation, the volume of the antibacterial agent 15 that is immersed in the recovered water 14 increases, and the antibacterial agent 15 returns to the recovered water 14. The elution amount of the antibacterial component can be increased.

  Therefore, the present embodiment can provide the same effects as those of the third embodiment (FIG. 4). Moreover, by providing the reserve tank 19, water can be replenished to the recovered water tank 5 promptly and more reliably after the power generation operation is stopped.

  As the electromagnetic valve 21, either a normally open valve or a normally closed valve may be used.

  When the exhaust heat of the fuel cell 1 is used in a hot water storage device or the like, a hot water storage tank may be provided in the fuel cell system 400. In this case, the hot water storage tank can be used as the reserve tank 19.

Example 1
Here, the range of the elution concentration of the antibacterial component (silver ion) when a silver antibacterial agent was used was examined.

  First, mold nutrients (for example, a mold medium) were added to pure water so as to be 10 mg / L, and used as test water. Next, the fungus culture saturated solution was added to the test water at a ratio of 1/100 to obtain a fungus added solution. An appropriate amount of a solution in which a silver antibacterial agent was dissolved was added to the fungus-added solution to prepare a plurality of culture solutions having different silver concentrations. Thereafter, these culture solutions were subjected to shaking culture for 6 days in a 40 ° C. incubator. The antibacterial effect of the silver antibacterial agent in each culture solution was examined by visually confirming the temporal change in the turbidity of the solution after shaking culture. As a result, it was found that if the silver concentration of the culture solution is 10 μg / L or more, mold growth can be more effectively suppressed.

  In addition, the above experiment was performed using several types of silver antibacterial agents, and the minimum concentration at which no turbidity was observed in the culture solution after 6 days of shaking culture was determined, and the antibacterial effect concentration of the silver antibacterial agents was obtained. As a result, in one type of silver antibacterial agent, the silver concentration (antibacterial effect concentration) at which an antibacterial effect is observed is 25 μg / L, and in other types of silver antibacterial agents, the antibacterial effect concentration is 52 μg / L. L.

  On the other hand, when the elution concentration of the antibacterial component is too high, there is a problem that the burden on the ion exchanger increases. Therefore, the elution concentration of the antibacterial component is preferably 100 μg / L or less.

  In addition, the elution density | concentration of an antibacterial component changes with not only the kind of antibacterial agent but the shape. Specifically, the larger the contact area between the antibacterial agent and water, the greater the amount of antibacterial components that elute in water.

DESCRIPTION OF SYMBOLS 1 Fuel cell 2 Hydrogen generator 3 Combustion part 4 Cooling water tank 5 Recovery water tank 6 Purifier 7 Water feeder (pump)
8 Cooling water pump 9 Heat exchanger 10 Condenser 11 Filter 12 Activated carbon 13 Ion exchanger 14 Recovered water (condensed water)
DESCRIPTION OF SYMBOLS 15 Antibacterial agent 15a Antibacterial component 16 Level sensor 17 Solenoid valve 18 Water level controller 19 Reserve tank 20 Reserve tank water 21 Normally open valve 30 Water path (recovered water path)
32 Cooling water supply device 34 Cooling water channel 36 Overflow water channel 38 Reserve water channel

Claims (15)

A fuel cell;
A water utilization device that uses recovered water recovered from the exhaust gas discharged from the fuel cell;
A first water path for supplying the recovered water to the water utilization device;
A first water tank provided in the first water path and storing the recovered water;
In the first water path, a purifier having an activated carbon provided on the downstream side of the first water tank;
A water delivery device provided in the first water path for delivering the recovered water in the first water tank to the water-using device;
A fuel cell system comprising: an antibacterial agent provided upstream of the activated carbon in the first water path.   The fuel cell system according to claim 1, further comprising a filter provided downstream of the antibacterial agent in the first water path.   The fuel cell system according to claim 2, wherein the filter is arranged in the vicinity of the end face on the downstream side of the activated carbon in the purifier.   2. The fuel cell system according to claim 1, wherein the activated carbon and the antibacterial agent are disposed in the same container in order of the activated carbon and the antibacterial agent from above in the direction of gravity.   The fuel cell system according to claim 4, wherein an end face on the upstream side of the activated carbon is in contact with the antibacterial agent.   The first water path further includes an ion exchanger provided on the downstream side of the filter, and the ion exchanger, the filter, the activated carbon, and the antibacterial agent are arranged in this order from above in the direction of gravity. The fuel cell system according to claim 3.   The fuel cell system according to claim 6, wherein the ion exchanger is supported by the filter. Having a plurality of particles or pellets containing the antimicrobial agent;
The fuel cell system according to claim 1, wherein the plurality of particles or pellets are stored in a container that passes water.   2. The antibacterial agent according to claim 1, wherein the antibacterial agent is configured to increase the amount of the antibacterial component eluted from the antibacterial agent into water after the power generation operation is stopped than during the power generation operation of the fuel cell system. Fuel cell system.   The antibacterial agent is provided in the first water tank, and is immersed in the water in the first water tank after the power generation operation is stopped rather than during the power generation operation of the fuel cell system. The fuel cell system according to claim 9, wherein the volume of the portion that is configured is configured to increase.   During the power generation operation of the fuel cell system, the water level of the first water tank is maintained below the lower limit water level at which the entire antibacterial agent is immersed in the water in the first water tank, and after the power generation operation is stopped The fuel cell system according to claim 10, further comprising a water level controller that raises the water level of the first water tank more than during the power generation operation. A second water tank;
A second water path connecting the first water tank and the second water tank;
A valve provided in the second water path,
The fuel cell system according to claim 11, wherein the operation of the valve is controlled by the water level controller.   The fuel cell system according to claim 1, wherein the first water tank is made of a material containing the antibacterial agent.   The fuel cell system according to claim 1, wherein the antibacterial agent includes a silver-based antibacterial agent.   2. The fuel cell system according to claim 1, wherein the antibacterial agent is configured so that an antibacterial component thereof is eluted in a range of 10 μg / L to 100 μg / L in the collected water.

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