JP2008166052A - Water purification apparatus and fuel cell system having the same - Google Patents

Abstract

To divide a water tank and separate a storage unit that stores water having a relatively high impurity concentration and a storage unit that stores water having a relatively low impurity concentration that has passed through a purification mechanism. Can preferentially pass water with a relatively high impurity concentration through the purification mechanism and efficiently remove the impurities, preferentially supply water with a relatively low impurity concentration, and suppress the amount of water passing through the purification mechanism. Thus, the size can be reduced, the manufacturing is easy, and the cost can be reduced.
A water tank connected to a recovery line for recovering waste water and a supply line for supplying purified water, and a purification mechanism for purifying water, wherein the water tank includes the recovery line A recovery side storage unit for storing water having a relatively high impurity concentration, and a supply side storage unit for storing water having a relatively low impurity concentration, to which the supply line is connected; The purification mechanism is disposed in a storage unit connecting pipe that connects the recovery side storage unit and the supply side storage unit.
[Selection] Figure 1

Description

  The present invention relates to a water purification device and a fuel cell system having the same.

  Conventionally, since fuel cells have high power generation efficiency and do not emit harmful substances, they have been put into practical use as power generators for industrial and household use, or as power sources for artificial satellites and spacecrafts. Development is progressing as a power source for vehicles such as buses, trucks, passenger carts, and luggage carts. The fuel cell may be an alkaline aqueous solution (AFC), phosphoric acid (PAFC), molten carbonate (MCFC), solid oxide (SOFC), direct methanol (DMFC), etc. Although good, a polymer electrolyte fuel cell (PEMFC) is common.

  In this case, the solid polymer electrolyte membrane is sandwiched between two gas diffusion electrodes and integrated to join. When one of the gas diffusion electrodes is used as a fuel electrode (anode electrode) and hydrogen gas as fuel is supplied to the surface, hydrogen is dissociated into hydrogen ions (protons) and electrons, and the hydrogen ions are converted into a solid polymer electrolyte. Move the membrane. Further, when the other of the gas diffusion electrodes is an oxygen electrode (cathode electrode) and air as an oxidant is supplied to the surface, oxygen in the air is combined with the hydrogen ions and electrons to generate water. The An electromotive force is generated by such an electrochemical reaction.

  And the system which circulates cooling water in order to cool a solid polymer electrolyte membrane is proposed (for example, refer patent documents 1 and 2). In addition, since the solid polymer fuel cell needs to maintain both sides of the solid polymer electrolyte membrane in a wet state, a system for supplying water to the air flow path has also been proposed.

By the way, in a system for supplying water to the air flow path, the mixing of impurities is one of the causes of performance degradation. In particular, when metal ions are mixed into the solid polymer electrolyte membrane or the gas diffusion electrode, the influence is great. Such impurities are mainly mixed in the following two sources.
(1) Impurities in the air as oxidizing agents (dust, dust, rainwater, aerosol, sea salt, yellow sand, pollen, etc.)
(2) Elution components from the components of the fuel cell system (piping, electrode members, gaskets, adhesives, etc.)
For this reason, measures such as disposing a filter for removing impurities in the air and selecting a material for the constituent member from materials with little elution are taken. However, since the impurities cannot be sufficiently reduced, a water purifier that removes impurities dissolved in the heated water with an adsorbent such as activated carbon or an ion exchange resin is also used.

  FIG. 2 is a view showing a conventional water purification apparatus.

  In FIG. 2A, reference numeral 101 denotes a water tank that stores water recovered from a fuel cell (FC) (not shown) through a recovery pipe line 105. The water stored in the water tank 101 is indicated by 106. The water tank 101 is connected to a supply line 104 for supplying water to the fuel cell, and the supply line 104 is provided with a water supply pump 102 and a purification filter 103. The water from the water tank 101 is purified by removing impurities by the purification filter 103 and then supplied to the fuel cell.

In the example shown in FIG. 2B, the purification filter 103 is not disposed in the supply conduit 104 but is disposed in the circulation conduit 107 that circulates water by the circulation pump 108. .
Japanese Patent Laid-Open No. 9-19678 Japanese Patent Laid-Open No. 10-233224

However, in the conventional water purification device, the water purification device becomes large or the impurity concentration of water supplied to the fuel cell becomes high. In the example shown in FIG. 2A, since all the water supplied to the fuel cell passes through the purification filter 103, the level of impurities can be kept low. However, in order to sufficiently remove impurities, it is necessary to set SV (Space Velocity) to about 30 [hr ⁻¹ ] or less from the relationship of the contact probability between the impurities and the purification filter 103. It will become. On the other hand, in the example shown in FIG. 2B, the water purification device can be reduced in size, but only a part of the water can be purified and impurities remain in the water tank 101. The impurity concentration of water supplied to the fuel cell becomes high.

  The present invention solves the problems of the conventional water purification device, divides the water tank, and stores the water having a relatively high concentration of recovered impurities, and the impurity concentration that has passed through the purification mechanism. By separating the housing portion that contains relatively low water, water with a relatively high impurity concentration can be preferentially passed through the purification mechanism to efficiently remove impurities, and the impurity concentration is relatively low. A water purification device that can supply water at a low level with priority, can reduce the size of the purification mechanism by reducing the amount of water passing through, is easy to manufacture, and has a low cost, and a fuel cell system having the water purification device For the purpose.

  For this purpose, the water purification apparatus of the present invention has a water tank to which a recovery pipeline for collecting waste water and a supply pipeline for supplying purified water are connected, and a purification mechanism for purifying water. The water tank is connected to the recovery pipe and receives a water having a relatively high impurity concentration. The water tank is connected to the supply side, and the supply pipe is connected to hold a water having a relatively low impurity concentration. The purification mechanism is disposed in a storage unit connecting conduit that connects the recovery side storage unit and the supply side storage unit.

  In another water purification apparatus of the present invention, the water tank further includes a water level adjusting mechanism that adjusts a water level difference between the recovery-side storage unit and the supply-side storage unit.

  In still another water purification apparatus according to the present invention, the water level adjusting mechanism is a valve that opens and closes according to the water level or water pressure of the recovery-side storage unit and the supply-side storage unit.

  In still another water purification apparatus according to the present invention, the water tank further includes a buffer unit disposed between the recovery side storage unit and the supply side storage unit.

  In the fuel cell system of the present invention, a fuel cell in which an electrolyte layer is sandwiched between a fuel electrode and an oxygen electrode includes a fuel cell assembly connected in large numbers in series and the water purification device, and the supply side housing The water supplied from the section is sprayed onto the oxygen electrode, the water discharged from the oxygen electrode is collected and returned to the collection side accommodating section.

  According to the configuration of the first aspect, it is possible to efficiently remove impurities by preferentially passing water having a relatively high impurity concentration through the purification mechanism. In addition, water with a relatively low impurity concentration can be preferentially supplied, and the water flow rate of the purification mechanism can be suppressed to reduce the size. Furthermore, since the manufacturing is easy, the cost can be reduced.

  According to the configuration of the second aspect, it is possible to allow water to flow from one to the other in an appropriate manner in response to fluctuations in the water levels of the collection-side storage unit and the supply-side storage unit. For this reason, water is always stored in the recovery-side storage section and can always be passed through the purification mechanism, so that the water can be purified stably. Moreover, since water is always accommodated in the supply side accommodating portion, the required amount of water can be reliably supplied.

  According to the structure of Claim 3, by controlling a valve appropriately, water can be made to flow in from one side to the other corresponding to the state of the water of a collection | recovery side accommodating part and a supply side accommodating part.

  According to the fourth aspect of the present invention, when water flows from the recovery side accommodating part to the supply side accommodating part due to fluctuations in the water level of the recovery side accommodating part and the supply side accommodating part, the water from the recovery side accommodating part is buffered. Since it is diluted with the water of the part, it is possible to suppress an increase in the impurity concentration of water in the supply side accommodating part. In addition, when water flows from the supply-side storage unit into the recovery-side storage unit, the water from the supply-side storage unit is diluted by the water in the buffer unit, so that a decrease in the impurity concentration of water in the recovery-side storage unit is suppressed. can do. Therefore, water with a high impurity concentration can be passed through the purification mechanism, and impurities can be efficiently removed.

  According to the fifth aspect of the present invention, since water with a low impurity concentration is supplied to the fuel cell, it is possible to suppress a decrease in the performance of the fuel cell. Further, even if the power generation status of the fuel cell fluctuates, the amount of water required for the fuel cell can be reliably supplied.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 3 is a diagram showing the configuration of the fuel cell system according to the first embodiment of the present invention.

  In the figure, reference numeral 11 denotes a fuel cell stack as a fuel cell device, which is used as a power source for vehicles such as passenger cars, buses, trucks, passenger carts and luggage carts. Here, the vehicle is equipped with a large number of auxiliary devices that consume electricity, such as lighting devices, radios, and power windows, which are used even when the vehicle is stopped. Since the output range is extremely wide, it is desirable to use the fuel cell stack 11 as a power source in combination with a capacitor unit 63 as a power storage means described later.

  The fuel cell stack 11 may be an alkaline aqueous solution type, phosphoric acid type, molten carbonate type, solid oxide type, direct type methanol, or the like, but is preferably a solid polymer type fuel cell. .

  More preferably, PEMFC (Proton Exchange Membrane Fuel Cell) type fuel cell or PEM (Proton Exchange Membrane) using hydrogen gas as fuel gas, that is, anode gas, and oxygen or air as oxidant, that is, cathode gas. ) Type fuel cell. Here, the PEM type fuel cell is generally a fuel cell in which a catalyst, an electrode, and a separator are combined on both sides of a solid polymer electrolyte membrane as an electrolyte layer that moves ions such as protons. Are composed of a plurality of stacks connected in series.

  In the present embodiment, the fuel cell stack 11 has a plurality of cell modules (not shown). The cell module includes a unit cell (MEA) as a fuel cell, electrically connecting the unit cells to each other, and a flow path of hydrogen gas as an anode gas and air introduced into the unit cell. A separator is separated from each other as a set, and a plurality of sets are stacked in the thickness direction. In the cell module, unit cells and separators are stacked in multiple stages so that the unit cells are arranged with a predetermined gap (gap) therebetween.

  In this case, the cell modules are connected to each other so that they can conduct electricity and the fuel flow path, that is, the hydrogen gas flow path is continuous.

  The unit cell is composed of an air electrode as an oxygen electrode provided on the side of the solid polymer electrolyte membrane as the electrolyte layer and a fuel electrode provided on the other side. The air electrode includes an electrode diffusion layer made of a conductive material that permeates while diffusing the reaction gas, and a catalyst layer that is formed on the electrode diffusion layer and is supported in contact with the solid polymer electrolyte membrane. In addition, the current collector in contact with the electrode diffusion layer on the air electrode side of the unit cell, and the air electrode side collector as a net-like current collector formed with a large number of openings through which a mixed flow of air and water is transmitted; And a fuel electrode side collector as a net-like current collector for contacting the electrode diffusion layer on the fuel electrode side of the unit cell and leading out current to the outside.

  In the unit cell, water moves. In this case, when a fuel gas, that is, hydrogen gas as an anode gas is supplied into the fuel chamber of the fuel electrode side collector, hydrogen is decomposed into hydrogen ions and electrons, and the hydrogen ions are accompanied by proton-entrained water. Permeates the electrolyte membrane. Further, when the air electrode is a cathode electrode and an oxidant, that is, air as a cathode gas is supplied into an oxygen chamber as an oxidant flow path, oxygen in the air is combined with the hydrogen ions and electrons, Water is produced. Moisture permeates through the solid polymer electrolyte membrane as reverse diffusion water and moves into the fuel chamber of the fuel electrode side collector. Here, the reverse diffusion water means that water generated in an oxygen chamber as an air channel diffuses into the solid polymer electrolyte membrane and permeates through the solid polymer electrolyte membrane in the direction opposite to the hydrogen ions. It has penetrated into the fuel chamber.

  In the figure, an apparatus for supplying hydrogen gas as a fuel gas to the fuel cell stack 11 and an apparatus for supplying air as an oxidant are shown. Although hydrogen gas, which is fuel taken out by reforming methanol, gasoline, or the like by a reformer (not shown), can be directly supplied to the fuel cell stack 11, it is stable and sufficient even during high-load operation of the vehicle. In order to be able to supply an amount of hydrogen gas, it is desirable to supply the hydrogen gas stored in the fuel storage means 21. Thereby, the hydrogen gas is always sufficiently supplied at a substantially constant pressure, so that the fuel cell stack 11 can follow the fluctuation of the load of the vehicle and supply a necessary current. .

  Hydrogen gas is stored in a container containing a hydrogen storage alloy, a container containing a hydrogen storage liquid such as decalin, a fuel storage means 21 such as a hydrogen gas cylinder, a first fuel supply line 22 as a fuel supply line, and The fuel is supplied to an inlet of a fuel gas flow path of the fuel cell stack 11 through a second fuel supply pipe 33 as a fuel supply pipe connected to the first fuel supply pipe 22. The first fuel supply line 22 includes a fuel storage means on-off valve 23, a first pressure sensor 27a, a first fuel pressure adjustment valve 25a, a second fuel pressure adjustment valve 25b, a fuel supply electromagnetic valve 26, and a first A three pressure sensor 27c is provided. The first fuel supply line 22 is connected to a bypass line 22a that bypasses the second fuel pressure regulating valve 25b, and a second pressure sensor 27b and an activation solenoid valve 26a are connected to the bypass line 22a. Arranged.

  In this case, the fuel storage means 21 has a sufficiently large capacity and is capable of always supplying sufficiently high pressure hydrogen gas. In the example shown in the figure, a plurality of, for example, three fuel storage means 21 are provided, and the first fuel supply conduit 22 is divided into a plurality at the portion connected to each fuel storage means 21. It is divided and merges on the way to become one. The fuel storage means 21 may be singular or plural, and may be any number when plural.

  Then, hydrogen gas discharged as an unreacted component from the outlet of the hydrogen gas flow path of the fuel cell stack 11 is discharged out of the fuel cell stack 11 through the first fuel discharge pipe 30. A suction circulation pump 36 as a pump is disposed in the first fuel discharge pipe 30. A hydrogen circulation electromagnetic valve 34 is disposed in the first fuel discharge pipe 30. Further, the end of the first fuel discharge line 30 opposite to the fuel cell stack 11 is connected to the second fuel supply line 33. Thereby, the hydrogen gas discharged out of the fuel cell stack 11 can be recovered, supplied to the hydrogen gas flow path of the fuel cell stack 11 and reused.

  Further, a second fuel discharge line 38 is connected between the fuel cell stack 11 and the suction circulation pump 36 in the first fuel discharge line 30, and the second fuel discharge line 38 has a hydrogen start exhaust gas. An electromagnetic valve 37 is provided so that hydrogen gas discharged from the fuel gas flow path when the fuel cell stack 11 is started can be discharged into the atmosphere. The outlet end of the second fuel discharge pipe 38 is connected to the exhaust manifold 13.

  Further, a third fuel discharge line 38 a having the other end connected to the second fuel discharge line 38 is provided between the suction circulation pump 36 and the hydrogen circulation electromagnetic valve 34 in the first fuel discharge line 30. It is connected. The third fuel discharge line 38a is provided with a reduced-pressure hydrogen discharge valve 37a that is opened when the inside of the fuel cell stack 11 is depressurized. The first fuel discharge pipe 30 is connected to an outside air introduction electromagnetic valve 35 and an air filter 35a so that outside air can be introduced when the fuel cell stack 11 is stopped.

  Here, the first fuel pressure regulating valve 25a and the second fuel pressure regulating valve 25b are those of a butterfly valve, a regulator valve, a diaphragm type valve, a mass flow controller, a sequence valve, etc., but the first fuel pressure regulating valve Any type of hydrogen gas may be used as long as the pressure of the hydrogen gas flowing out from the outlets of 25a and the second fuel pressure regulating valve 25b can be adjusted to a preset pressure. The pressure adjustment may be performed manually, but is preferably performed by an actuator including an electric motor, a pulse motor, an electromagnet, or the like.

  The fuel supply solenoid valve 26, the start-up solenoid valve 26a, the hydrogen circulation solenoid valve 34, and the hydrogen start-up exhaust solenoid valve 37 are so-called on-off types, and are composed of an electric motor, a pulse motor, an electromagnet, and the like. Actuated by an actuator. The fuel storage means original opening / closing valve 23 is operated manually or automatically using an electromagnetic valve. Further, the suction circulation pump 36 may be of any type as long as it can forcibly discharge the reverse diffusion water together with the hydrogen gas and can bring the inside of the fuel gas passage into a negative pressure state. Good.

  On the other hand, the air as the oxidant passes through the air filter 53 and is sucked into the air supply fan 51 as the oxidant supply source, and from the air supply fan 51 through the air supply line 52 and the intake manifold 12. The fuel cell stack 11 is supplied to an oxygen chamber as an oxidant flow path, that is, an air flow path. In this case, the pressure of the supplied air is a normal pressure of about atmospheric pressure. The air supply fan 51 may be of any type as long as it can suck and discharge air. The air filter 53 may be of any type as long as dust, impurities, etc. contained in the air can be removed. Note that oxygen can be used as the oxidizing agent instead of air. And the air discharged | emitted from an air flow path is discharged | emitted in air | atmosphere through the exhaust manifold 13, the condenser 14, the outlet side exhaust manifold 54, and the exhaust port 55 as a manifold. The exhaust manifold 13 is provided with a stack exhaust temperature detector 56 for detecting the temperature of air immediately after being discharged from the fuel cell stack 11, and the outlet side exhaust manifold 54 is immediately after being discharged from the condenser 14. A condenser exhaust temperature detector 57 for detecting the temperature of the air is provided.

  The air supply pipe 52 is supplied with water sprayed into the air supplied to the air flow path, and water for maintaining the air electrode as the oxygen electrode of the fuel cell stack 11 in a wet state. A supply nozzle 47 is provided. The air electrode and the fuel electrode can be cooled by the sprayed water. Further, the condenser 14 disposed at the end of the exhaust manifold 13 is for condensing and removing moisture in the air discharged from the fuel cell stack 11, and is condensed by the condenser 14. The water thus collected is collected in the water tank 43 through the condensed water discharge pipe 41. A drainage pump 42 is disposed in the condensed water discharge pipe 41, and a level gauge 45 is attached to the water tank 43. In addition, the fuel cell system has a water purification device to be described later in order to purify the water stored in the water tank 43.

  The water in the water tank 43 is supplied to the water supply nozzle 47 through the water supply pipe 46. A water supply pump 44 is disposed in the water supply pipe 46. Here, the drainage pump 42 and the water supply pump 44 may be of any type as long as they can suck and discharge water. The condensed water discharge pipe 41, the drainage pump 42, the water tank 43, the water supply pump 44, and the water supply pipe 46 function as a water circulation system.

  Furthermore, an inverter device 61 as a drive control device as a load and a capacitor unit 63 as a power storage unit are connected in parallel to an electric terminal (not shown) of the fuel cell stack 11. The capacitor unit 63 includes a capacitor (capacitor) such as an electric double layer capacitor. In addition, the said electrical storage means does not necessarily need to be a capacitor, and secondary batteries, such as a lead storage battery, a nickel cadmium battery, a nickel hydride battery, a lithium ion battery, and a sodium sulfur battery, may be what is called a battery (storage battery). Any form may be used as long as it has a function of electrically storing and discharging energy, such as a flywheel, a superconducting coil, and a pressure accumulator. Furthermore, any of these may be used alone, or a plurality of them may be used in combination.

  Further, the inverter device 61 converts a direct current from the fuel cell stack 11 or the capacitor unit 63 into an alternating current and supplies the alternating current to an unillustrated alternating current motor that is a drive source for rotating the wheels of the vehicle. Here, in the fuel cell system, the fuel cell stack 11 or the capacitor unit 63 is connected in parallel to supply current to the inverter device 61. For example, when the vehicle is stopped, the fuel cell stack When the stack 11 is stopped or when the current from the fuel cell stack 11 does not satisfy the required current during high load operation such as on a slope, the current is automatically supplied from the capacitor unit 63 to the inverter device 63. The

  Reference numeral 62 denotes an IGBT unit including an IGBT (insulated gate bipolar transistor) which is a high-speed switching element as a charging switching element, and is a control circuit that controls charging of the capacitor unit 63.

  When the AC motor functions as a power generator during vehicle deceleration operation and generates a so-called regenerative current, the regenerative current is supplied to the capacitor unit 63 during the vehicle deceleration operation, and the capacitor unit 63 Recharged. Further, even when the regenerative current is not supplied, when the capacitor unit 63 is discharged and the terminal voltage decreases, the current generated by the fuel cell stack 11 is automatically supplied to the capacitor unit 63.

  As described above, in the fuel cell system, when the capacitor unit 63 is constantly charged and the current from the fuel cell stack 11 alone does not satisfy the required current, the current is supplied from the capacitor unit 63 to the inverter device 63. Since the vehicle is automatically supplied, the vehicle can travel stably in various travel modes.

  In the present embodiment, the fuel cell system has an FC control ECU (Electronic Control Unit) (not shown) as a control device. The control device includes arithmetic means such as a CPU and MPU, storage means such as a magnetic disk and a semiconductor memory, an input / output interface, and the like, and is supplied from various sensors to the fuel gas flow path and the air flow path of the fuel cell stack The air supply fan 51, the first fuel pressure adjustment valve 25a, the second fuel pressure adjustment valve 25b, the fuel supply electromagnetic valve 26, hydrogen are detected by detecting the flow rate, temperature, output voltage, etc. of hydrogen, oxygen, air, etc. The operation of the circulation electromagnetic valve 34, the suction circulation pump 36, the drainage pump 42, the water supply pump 44, the water purification device, and the like is controlled. Further, the FC control ECU cooperates with other sensors provided in the vehicle and an EV (Electric Vehicle) control ECU (not shown) as a vehicle control means to supply fuel and oxidant to the fuel cell stack 11. Centrally control the operation of all equipment supplied.

  Next, the configuration of the water purification device will be described in detail.

  FIG. 1 is a diagram showing a configuration of a water purification apparatus according to the first embodiment of the present invention, and FIG. 4 is a table showing an operation of the water purification apparatus according to the first embodiment of the present invention.

  As shown in FIG. 1, the water tank 43 is divided into two by a partition plate 75 disposed inside, and has two accommodating portions A and B. The storage part A is a recovery side storage part that stores water having a relatively high impurity concentration, and is connected to a condensed water discharge pipe 41 that functions as a recovery pipe that returns the recovered water to the water tank 43. . The accommodating portion B is a supply-side accommodating portion that accommodates water having a relatively low impurity concentration, and is connected to a water supply conduit 46 that functions as a supply conduit that supplies water from the water tank 43. And the accommodating part connection pipeline 71 is connected so that the accommodating parts A and B may be connected, and the pump 72 for water purification and the purification | cleaning filter 73 are arrange | positioned at this accommodating part coupling pipeline 71. FIG. The purification filter 73 may be of any kind as long as it removes dust, impurities and the like contained in water. The water purification pump 72 and the purification filter 73 act as a purification mechanism for purifying water.

  The water discharged from the fuel cell stack 11 and condensed and recovered by the condenser 14 flows into the storage portion A through the condensed water discharge pipe 41 and is stored. Further, the water stored in the storage portion B is supplied to the fuel cell stack 11 through the water supply pipe 46 by the water supply pump 44. Further, the water purification pump 72 operates continuously, passes the water stored in the storage portion A through the purification filter 73, and removes, that is, purifies the impurities in the water. Then, the water from which impurities have been removed by passing through the purification filter 73 flows into the storage portion B and is stored.

  Here, the water recovered from the fuel cell stack 11 inevitably contains impurities. For example, dust, rainwater, aerosol, sea salt, yellow sand, pollen and the like contained in the air supplied to the air flow path are included as impurities. Further, for example, components eluted from various members constituting the fuel cell stack 11 such as pipes, electrode members, gaskets, and adhesives are included as impurities. Therefore, the water accommodated in the accommodating part A has a relatively high impurity concentration. On the other hand, the water accommodated in the accommodating part B has passed through the purification filter 73 and impurities have been removed, so that the impurity concentration is relatively low.

  Incidentally, the amount of water supplied to the fuel cell stack 11 and the amount of water recovered from the fuel cell stack 11 vary depending on the power generation status of the fuel cell stack 11. That is, it increases when the power generation amount is large, and decreases when the power generation amount is small.

  On the other hand, the amount of water flowing from the storage portion A through the purification filter 73 and flowing into the storage portion B is constant. However, the purification filter 73 is relatively small and cannot purify a large amount of water at a time, and the water flow rate is limited. Further, the water purification pump 72 is also relatively small, and the amount of discharged water corresponds to the water flow rate of the purification filter 73. That is, the purification mechanism has a small capacity. The amount of water flowing from the storage portion A through the purification filter 73 and flowing into the storage portion B is the maximum value of the amount of water supplied to the fuel cell stack 11 and the amount of water recovered from the fuel cell stack 11. Is smaller than

Therefore, the water levels L _A and L _B indicating the amounts of water in the accommodating portions A and B vary as shown in FIG. The supply water amount is the amount of water supplied to the fuel cell stack 11, and the purified water amount is the amount of water that flows from the storage portion A through the purification filter 73 and flows into the storage portion B. Further, since the partition plate 75 is set to have a height lower than the height to the ceiling surface in the water tank 43, one of the water levels L _A or L _{B of} the housing part A or B rises and the partition plate 75 When the height exceeds 75, water flows over the partition plate 75 to the other.

  In addition, when water flows into the storage part B from the storage part A beyond the partition plate 75, unpurified water is mixed in, so the impurity concentration of the water stored in the storage part B increases. However, the impurity concentration of the water as it is recovered from the fuel cell stack 11 accommodated in the accommodating portion A is kept lower. Therefore, since water is always accommodated in the accommodating portion B, the required amount of water can be reliably supplied to the fuel cell stack 11 even if the power generation state of the fuel cell stack 11 fluctuates.

  As described above, in the present embodiment, the water tank 43 is divided, and the storage unit A that stores the high-impurity concentration water recovered from the fuel cell stack 11 and the low-impurity concentration water that has passed through the purification mechanism. The accommodating part B to accommodate is isolate | separated. Therefore, water having a high impurity concentration is allowed to pass through the purification mechanism, so that impurities can be efficiently removed. In addition, since water with a low impurity concentration is supplied to the fuel cell stack 11, it is possible to suppress the performance degradation of the fuel cell stack 11.

  Next, a second embodiment of the present invention will be described. In addition, about the thing which has the same structure as 1st Embodiment, the description is abbreviate | omitted by providing the same code | symbol. The description of the same operation and the same effect as those of the first embodiment is also omitted.

  FIG. 5 is a diagram showing the configuration of the water purification apparatus according to the second embodiment of the present invention, and FIG. 6 is a table showing the operation of the water purification apparatus according to the second embodiment of the present invention.

  In the present embodiment, a differential pressure valve 76 as a water level adjusting mechanism is disposed below the partition plate 75. The differential pressure valve 76 opens when the difference in water pressure indicating the amount of water in the accommodating portions A and B exceeds a specified value, and allows the inflow of water from one of the accommodating portions A or B to the other. The specified value can be arbitrarily set.

Thus, housing section amount of water in the A is increased relative to the amount of water in the housing portion B, and the water pressure P _A in the housing portion A is larger than the prescribed value than the pressure P _B in the housing portion B, whereas The differential pressure valve 76 is opened, and the water in the storage portion A flows into the storage portion B. The accommodating portion water in is increased compared to the amount of water in the housing part A B, the pressure P _B in the housing portion B is increased beyond a prescribed value than the pressure P _A in the storage unit A, the other The differential pressure valve 76 is opened, and the water in the storage part B flows into the storage part A.

  Since the configuration and operation of other points are the same as those in the first embodiment, description thereof is omitted.

  As described above, in the present embodiment, since the differential pressure valve 76 is disposed on the partition plate 75, by setting the specified value to an appropriate value, fluctuations in the water level in the accommodating portions A and B can be prevented. Appropriately, water can flow from one to the other. Therefore, water is always stored in the storage part A and can always be passed through the purification filter 73, so that the water can be purified stably. Further, since water is always stored in the storage portion B, the required amount of water can be reliably supplied to the fuel cell stack 11 even if the power generation state of the fuel cell stack 11 fluctuates.

  Furthermore, the water purification device and the fuel cell system in the present embodiment also have the same effects as the water purification device and the fuel cell system in the first embodiment.

  Next, a third embodiment of the present invention will be described. In addition, about the thing which has the same structure as 1st and 2nd embodiment, the description is abbreviate | omitted by providing the same code | symbol. Also, the description of the same operations and effects as those of the first and second embodiments is omitted.

  FIG. 7 is a diagram showing the configuration of the water purification apparatus according to the third embodiment of the present invention, and FIG. 8 is a table showing the operation of the water purification apparatus according to the third embodiment of the present invention.

In the present embodiment, an opening / closing valve 77 as a water level adjusting mechanism provided with a float 77 a is provided below the partition plate 75. The on-off valve 77 is opened when the water levels L _A and L _B indicating the amounts of water in the accommodating portions A and B become less than a specified value, and allows the inflow of water from one of the accommodating portions A and B to the other. The specified value can be arbitrarily set.

Thus, housing section water is reduced in B, when the water level L _B of the housing portion B is less than a specified value, one of the opening and closing valve 77 is opened, water in the accommodation unit A flows into the housing portion B . The accommodating portion water is reduced in A, when the water level L _A of the housing portion A is less than the specified value, and opens the second on-off valve 77, the water containing portion B flows into the accommodating portion A .

  Since the configuration and operation of other points are the same as those in the first embodiment, description thereof is omitted.

Thus, in the present embodiment, the opening / closing valve 77 that is opened when the water levels L _A and L _B are less than the specified value is disposed on the partition plate 75, so that the specified value is set to an appropriate value. Thus, water can be allowed to flow from one to the other in an appropriate manner in response to fluctuations in the water levels in the accommodating portions A and B. Therefore, water is always stored in the storage part A and can always be passed through the purification filter 73, so that the water can be purified stably. Further, since water is always stored in the storage portion B, the required amount of water can be reliably supplied to the fuel cell stack 11 even if the power generation state of the fuel cell stack 11 fluctuates.

  Furthermore, the water purification device and the fuel cell system in the present embodiment also have the same effects as the water purification device and the fuel cell system in the first embodiment.

  Next, a fourth embodiment of the present invention will be described. In addition, about the thing which has the same structure as the 1st-3rd embodiment, the description is abbreviate | omitted by providing the same code | symbol. Explanation of the same operations and effects as those of the first to third embodiments is also omitted.

  FIG. 9 is a diagram showing the configuration of the water purification apparatus in the fourth embodiment of the present invention, and FIG. 10 is a table showing the operation of the water purification apparatus in the fourth embodiment of the present invention.

In the present embodiment, in addition to the accommodating portion connecting conduit 71, a second accommodating portion connecting conduit 78 is connected so as to connect the accommodating portions A and B, and the second accommodating portion connecting conduit 78 has a water level. A water control valve 79 is provided as an adjustment mechanism. In addition, the storage units A and B are provided with state detection sensors S _A and S _B that detect the water levels in the storage units A and B, such as the water level. Then, the control device, the state detection sensor S _A and S level of the accommodation unit A and in B based on the detection output of the _B, to determine the state of the water pressure, etc., to open and close the water control valve 79. For example, if it is determined that one of the water levels L _A or L _{B of} the containing part A or B is below a specified value, the water control valve 79 is opened to allow water to flow from one of the containing parts A or B to the other. To do. The specified value can be arbitrarily set.

  Since the configuration and operation of other points are the same as those in the first embodiment, description thereof is omitted.

  Thus, in the present embodiment, the water control valve 79 that opens and closes based on the state of the water in the accommodating portions A and B is disposed in the second accommodating portion connecting pipeline 78 that connects the accommodating portions A and B. Therefore, by appropriately controlling the water control valve 79, water can be allowed to flow from one to the other appropriately corresponding to the state of the water in the accommodating portions A and B. Therefore, water is always stored in the storage part A and can always be passed through the purification filter 73, so that the water can be purified stably. Further, since water is always stored in the storage portion B, the required amount of water can be reliably supplied to the fuel cell stack 11 even if the power generation state of the fuel cell stack 11 fluctuates.

  Furthermore, the water purification device and the fuel cell system in the present embodiment also have the same effects as the water purification device and the fuel cell system in the first embodiment.

  Next, a fifth embodiment of the present invention will be described. In addition, about the thing which has the same structure as 1st-4th embodiment, the description is abbreviate | omitted by providing the same code | symbol. Explanation of the same operations and effects as those of the first to fourth embodiments is also omitted.

  FIG. 11 is a diagram showing the configuration of the water purification apparatus according to the fifth embodiment of the present invention, and FIG. 12 is a table showing the operation of the water purification apparatus according to the fifth embodiment of the present invention.

In the present embodiment, the water tank 43 is divided into three by a first partition plate 75a and a second partition plate 75b disposed inside, and the two storage portions A and B, and the storage portions A and B. A buffer part C as an accommodating part between the two. An opening / closing valve 77 having a float 77a is disposed below the first partition plate 75a and the second partition plate 75b. The on-off valve 77, housing section opened and the A and the water level L _A and L _B shows the amount of water in the B becomes less than the specified value, to permit flow of water into the housing part A and B from the buffer unit C. The specified value can be arbitrarily set.

Thus, housing section water is reduced in B, when the water level L _B of the housing portion B is less than a specified value, one of the opening and closing valve 77 is opened, the water in the buffer section C flows into the housing portion B . The accommodating portion water is reduced in A, when the water level L _A of the housing portion A is less than the specified value, and opens the second on-off valve 77, the water in the buffer section C flows into the accommodating portion A .

The first partition plate 75 a and the second partition plate 75 b are set to have a height lower than the height to the ceiling surface in the water tank 43. Therefore, receiving unit when the water level L _A and L _B of A and B exceeds the height of the first partition plate 75a and the second partition plate 75b to rise, housing part water first in the A and B It flows into the buffer part C beyond the partition plate 75a and the second partition plate 75b.

  Since the configuration and operation of other points are the same as those in the first and third embodiments, description thereof is omitted.

Thus, in this embodiment, since the buffer portion C between the housing part A and the housing portion B is formed, by variation of the water level L _A and L _B of housing part A and the B, housed When water flows from the part A into the storage part B, the water from the storage part A is diluted by the water in the buffer part C, so that an increase in the impurity concentration of water in the storage part B can be suppressed. . Therefore, since water with a high impurity concentration is not supplied to the fuel cell stack 11, it is possible to suppress performance degradation of the fuel cell stack 11.

Further, the variation of the water level L _A and L _B of housing part A and the B, the water in the housing unit A from the storage unit B when the inflowing water from the housing portion B is diluted with water in the buffer portion C Therefore, the fall of the impurity concentration of the water in the accommodating part A can be suppressed. Therefore, water with a high impurity concentration can be passed through the purification mechanism, and impurities can be efficiently removed.

  Furthermore, the water purification device and the fuel cell system in the present embodiment also have the same effects as the water purification device and the fuel cell system in the third embodiment.

  Next, a sixth embodiment of the present invention will be described. In addition, about the thing which has the same structure as 1st-5th embodiment, the description is abbreviate | omitted by providing the same code | symbol. Explanation of the same operations and effects as those of the first to fifth embodiments is also omitted.

  FIG. 13 is a diagram showing the configuration of the water purification apparatus according to the sixth embodiment of the present invention, and FIG. 14 is a table showing the operation of the water purification apparatus according to the sixth embodiment of the present invention.

  In the present embodiment, the water tank 43 is divided into four by a first partition plate 75a, a second partition plate 75b, and a third partition plate 75c disposed therein, and two storage portions A and B, and storage It has the 1st buffer part C1 and the 2nd buffer part C2 as an accommodating part between the part A and the accommodating part B. That is, the buffer part C is divided into two parts by the third partition plate 75c to form a first buffer part C1 and a second buffer part C2. The height of the third partition plate 75c is set to be lower than the height of the first partition plate 75a and the second partition plate 75b. Other configurations are the same as those in the fifth embodiment.

Thus, housing section water is reduced in B, when the water level L _B of the housing portion B is less than a specified value, and one of the opening and closing valve 77 is opened, the water in the second buffer portion C2 is accommodated portion B Inflow. The accommodating portion water is reduced in A, when the water level L _A of the housing portion A is less than the specified value, and opens the second on-off valve 77, the water in the first buffer portion C1 is accommodated portion A Inflow.

Further, when the water level L _A and L _B of housing part A and in B is greater than the height of the first partition plate 75a and the second partition plate 75b rises, the water of the receiving portion A and the B is a It flows into the 1st buffer part C1 and the 2nd buffer part C2 exceeding the 1st partition plate 75a and the 2nd partition plate 75b.

  Furthermore, when the water level of one of the first buffer part C1 or the second buffer part C2 exceeds the height of the third partition plate 75c, water flows into the other side beyond the third partition plate 75c.

  Since the configuration and operation of other points are the same as those of the fifth embodiment, description thereof is omitted.

  Thus, in the present embodiment, since the buffer unit C is divided into the first buffer unit C1 and the second buffer unit C2, the water purification device and the fuel cell system according to the fifth embodiment are the same. The effect to play increases.

  In the present embodiment, an example in which the buffer unit C is divided into two parts has been described. However, the buffer unit C can be divided into three or more parts. That is, the water tank 43 can be divided into five or more parts.

  The present invention is not limited to the above-described embodiment, and various modifications can be made based on the spirit of the present invention, and they are not excluded from the scope of the present invention.

  Furthermore, in the present embodiment, a case where a fuel cell stack in which a large number of fuel cells are stacked with separators interposed therebetween has been described. However, any fuel cell assembly in which a large number of fuel cells are connected in series will be described. Needless to say, the present invention may be applied to a structure having a different structure.

It is a figure which shows the structure of the water purification apparatus in the 1st Embodiment of this invention. It is a figure which shows the conventional water purification apparatus. It is a figure which shows the structure of the fuel cell system in the 1st Embodiment of this invention. It is a table | surface which shows operation | movement of the water purification apparatus in the 1st Embodiment of this invention. It is a figure which shows the structure of the water purification apparatus in the 2nd Embodiment of this invention. It is a table | surface which shows operation | movement of the water purification apparatus in the 2nd Embodiment of this invention. It is a figure which shows the structure of the water purification apparatus in the 3rd Embodiment of this invention. It is a table | surface which shows operation | movement of the water purification apparatus in the 3rd Embodiment of this invention. It is a figure which shows the structure of the water purification apparatus in the 4th Embodiment of this invention. It is a table | surface which shows operation | movement of the water purification apparatus in the 4th Embodiment of this invention. It is a figure which shows the structure of the water purification apparatus in the 5th Embodiment of this invention. It is a table | surface which shows operation | movement of the water purification apparatus in the 5th Embodiment of this invention. It is a figure which shows the structure of the water purification apparatus in the 6th Embodiment of this invention. It is a table | surface which shows operation | movement of the water purification apparatus in the 6th Embodiment of this invention.

Explanation of symbols

11 Fuel Cell Stack 41 Condensed Water Discharge Pipe 43 Water Tank 46 Water Supply Pipe 71 Storage Port Connection Pipe 72 Water Purification Pump 73 Purification Filter 76 Differential Pressure Valve 77 On-off Valve 79 Water Control Valve

Claims (5)

A water tank connected to a recovery line for recovering waste water and a supply line for supplying purified water;
A water purification device having a purification mechanism for purifying water,
The water tank is connected to the recovery pipe and receives a water having a relatively high impurity concentration, and a recovery-side storage section that receives water having a relatively low impurity concentration. Provided with a supply-side container,
The water purification apparatus, wherein the purification mechanism is disposed in a storage unit connecting pipe that connects the recovery side storage unit and the supply side storage unit.   The water purification apparatus according to claim 1, wherein the water tank includes a water level adjustment mechanism that adjusts a water level difference between the recovery-side storage unit and the supply-side storage unit.   The water purification apparatus according to claim 2, wherein the water level adjusting mechanism is a valve that opens and closes according to a water level or a water pressure of the recovery-side storage unit and the supply-side storage unit.   The said water tank is a water purification apparatus of Claim 1 provided with the buffer part arrange | positioned between the said collection | recovery side accommodating part and a supply side accommodating part. A fuel cell assembly in which a plurality of fuel cells each having an electrolyte layer sandwiched between a fuel electrode and an oxygen electrode are connected in series;
A fuel cell system comprising the water purification device according to any one of claims 1 to 4,
A fuel cell system, wherein water supplied from the supply-side accommodation unit is jetted to the oxygen electrode, and water discharged from the oxygen electrode is collected and returned to the collection-side accommodation unit.

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