JP2007242491A - Fuel cell system and its operation control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell system miniaturizing a humidifying bath and enhancing the performance of the whole of the system including power generation performance; and to provide the operation control method of the fuel cell system. <P>SOLUTION: The fuel cell system is equipped with an air supply passage 40 supplying oxidant gas through an oxidant electrode 25c of a fuel cell body 25; an initial humidifying bath 45 installed in the air supply passage 40 and humidifying air; a diaphragm type total heat exchanger 49 installed in the air supply passage 40 downstream than the initial humidifying bath 45, performing steam exchange and heat exchange between air going to the oxidant electrode 25c and air passed through the oxidant electrode 25c; and a solenoid shut-off valve 43 changing over air flow going to the oxidant electrode 25c to either one of the initial humidifying bath 45 and the diaphragm type total heat exchanger 49. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a fuel cell system suitable for supplying electric and thermal energy in a general household and an operation control method thereof.

  In recent years, a fuel cell system has been proposed in which a fuel cell body is combined with a reformer that reforms a hydrocarbon-based fuel such as city gas into hydrogen to generate a hydrogen-based fuel gas (for example, Patent Documents). 1). Such a fuel cell system has a great advantage that if the thermal energy is recovered from exhaust gas or cooling water from the fuel cell main body in addition to the electric energy generated by the fuel cell main body, the recovered thermal energy can be used for hot water supply. Have

In the case of a fuel cell main body used in this type of fuel cell system, the organic or inorganic electrolyte membrane sandwiched between the fuel electrode and the oxidizer electrode contains water, so that its original function is exhibited. Therefore, the air as the oxidant supplied to the oxidizer electrode is generally humidified during the supply process. For this reason, the system of Patent Document 1 uses a humidifying tank (such as warm water) A water tank 21) in FIG. 1 is provided, and air is diffused into the liquid in the humidifying tank by air diffused from a diffuser tube made of a porous plate such as sintered metal.
JP 2003-217629 A

  During normal operation of the fuel cell system, in order for the humidification tank to exhibit sufficient humidification performance, it is necessary to ensure a sufficiently deep liquid depth from the liquid surface to the aeration position of the diffusion tube in the humidification tank. For this reason, the capacity of the humidifying tank of Patent Document 1 must be increased. When the fuel cell system has a power generation capacity of 1 kW, the humidifying tank needs to humidify several tens of liters / minute (for example, about 70 to 80 l / min) of air during steady operation.

  In addition, in order to stabilize the humidification performance, it is necessary to maintain the above-mentioned liquid depth constant. For this reason, in the system of Patent Document 1, the liquid level in the humidification tank is always measured by a water level gauge. Monitoring and controlling the replenishment of the liquid to the humidification tank using a replenishment pump and a solenoid valve based on the signal from the water level gauge, the liquid level in the humidification tank is kept constant. For this reason, in addition to the large humidification tank of patent document 1, the control structure of the liquid level is complicated.

Note that in order to increase the humidification efficiency of the oxidizer air, that is, the air diffusion efficiency, reducing the diameter of the air diffuser opening of the air diffuser increases the pressure loss of the air in the air diffuser. The power consumption of the air pump that supplies air toward the tank increases.
Also, if the capacity of the humidification tank is reduced in addition to the reduced diameter of the diffuser opening, the liquid level in the humidification tank undulates up and down due to the bubbling of the diffused air bubbles, even if a wave-dissipating plate is used. It is difficult to keep the surface, that is, the liquid depth constant.

On the other hand, in the case of the system of Patent Document 1, since the liquid in the humidifying tank is supplied as a cooling liquid to the cooling part of the fuel cell main body, there is a possibility that a large amount of bubbles are included in the cooling liquid. For this reason, not only the cooling effect of the fuel cell main body is not sufficiently exhibited, but also the suction of the coolant pump itself used for supplying the coolant may be difficult.
Further, since the coolant after passing through the cooling part of the fuel cell main body is returned to the liquid through the humidification tank, the return of the coolant disturbs the liquid level, and the coolant in the humidification tank. As a result, the power consumption of the coolant pump is increased.

Furthermore, in the case of the system of Patent Document 1, since the liquid in the humidification tank is also supplied to the fuel reformer as the reforming liquid, it is used for supplying the reforming liquid as in the case of the cooling liquid pump. It becomes difficult to suck the reforming liquid pump itself, and the supply of the reforming liquid that requires quantitativeness becomes unstable.
Furthermore, the humidified air after passing through the oxidant electrode of the fuel cell body passes through the heat exchanger, and the heat energy is recovered from the humidified air by the heat exchanger, but the condensate generated at this time is Once returned to the recovery tank, the liquid in the recovery tank is supplied to the humidification tank through the above-described replenishment pump and electromagnetic valve. Since the humidified air after passing through the oxidizer electrode contains SOx and NOx impurities, the impurities accumulate together with the condensate in the humidification tank through the recovery tank, and cool the fuel cell body. The coolant supplied to the unit is contaminated. Such a contaminated coolant has a high electric conductivity, which is a factor that greatly reduces the power generation performance of the fuel cell body.

  The present invention has been made on the basis of the above-mentioned circumstances, and its object is to perform humidification of oxidant gas with a simple humidification tank without using a large humidification tank, and An object of the present invention is to provide a fuel cell system capable of improving the performance of the entire system and an operation control method thereof.

  In order to achieve the above object, a fuel cell system according to the present invention supplies a fuel cell body, a fuel supply passage for supplying fuel gas to the fuel cell body, and an oxidant gas for the fuel gas through the fuel cell body. And an oxidant supply channel having upstream and downstream portions respectively positioned upstream and downstream of the fuel cell body, a coolant supply channel for supplying a coolant through the fuel cell body, and an upstream of the oxidant supply channel A membrane-type total heat exchanger that exchanges heat and steam between the oxidant gas flowing through the part and the downstream part, and an upstream part of the oxidant supply flow path to disperse the oxidant gas into the liquid A humidifying tank that causes the oxidant gas to be sent out toward the fuel cell main body, and a separating means that is provided in an upstream part of the oxidant supply flow path and that can selectively separate the humidifying tank from the upstream part. With ( Motomeko 1).

  According to the fuel cell system described above, the humidifying tank is used for humidifying the oxidant gas when the fuel cell main body is before power generation or at the initial stage of power generation. A membrane-type total heat exchanger is used for humidification. In this membrane type total heat exchanger, the heat and vapor of the oxidant gas after passing through the oxidant electrode of the fuel cell main body are transferred to the oxidant gas toward the oxidant electrode, and humidification and temperature rise of the oxidant gas are performed. Do.

The humidification tank is preferably arranged upstream of the membrane type total heat exchanger (Claim 2). In this case, the humidification of the membrane of the membrane type total heat exchanger is caused by the oxidant gas humidified in the humidification tank. Done.
In addition, the humidification tank is provided in a sealed tank body, an aeration liquid chamber provided in the tank body, storing liquid and having an aeration position of an oxidant gas positioned in the liquid, and the tank body. An overflow that determines the liquid depth from the liquid level in the diffuser chamber to the diffuser position by partitioning the drainage chamber adjacent to the diffuser chamber and letting excess liquid in the diffuser chamber escape to the drainage chamber A weir and a float type drainer for discharging the liquid in the drainage chamber may be included.

According to the humidifying tank of the third aspect, the liquid depth from the liquid surface to the aeration position is kept constant only by continuously supplying the liquid into the aeration liquid chamber.
The coolant supply channel may include a sealed coolant circulation channel in a part thereof (Claim 4). In this case, the coolant circulation channel stores the circulation kinetic energy of the coolant. Further, the coolant supply channel may include a diffused liquid chamber of a humidifying tank in a part of the coolant supply channel (Claim 5).

In the case of the coolant circulation channel according to claim 5, the diffused liquid chamber has an inlet and an outlet positioned below the diffused position in the liquid for connection with the coolant circulating channel. (Claim 6) According to this configuration, mixing of bubbles into the coolant is prevented.
Specifically, the cooling liquid supply flow path includes a cooling flow path portion including a diffused liquid chamber, a cooling bypass flow path extending in parallel with the cooling liquid flow path portion, and a cooling bypass flow in the cooling liquid supply flow path. A heater inserted other than the passage, and a cooling switching means that opens one of the cooling flow path portion and the cooling bypass flow path and closes the other can be further provided.

According to the coolant supply channel of the seventh aspect, when the coolant is heated by the heater, the temperature of the liquid in the diffuser liquid chamber in the humidifying tank is increased simultaneously with the temperature increase of the fuel cell main body.
The separation means according to claim 1 is provided in the upstream portion of the oxidant supply flow path, and the humidification flow path portion including the diffused liquid chamber extends in parallel, the humidification bypass flow path, the humidification flow path portion, and the humidification bypass. Humidification switching means that opens one of the flow paths and closes the other can be included (claim 8). More specifically, the humidification switching means includes an openable / closable shutoff valve inserted in the humidification bypass flow path, and the shutoff valve is smaller than the flow resistance on the diffuser liquid chamber side when the valve is opened, and is oxidized. It has channel resistance that allows the entire flow rate of the agent gas to pass through (claim 9). In this case, when the shut-off valve is closed, the participant gas flows only through the humidifying channel portion including the diffused liquid chamber, is humidified in the diffused liquid chamber, and then is applied to the oxidant electrode of the fuel cell body. Supplied. On the other hand, when the shutoff valve is opened, the oxidant gas flows through the humidification bypass passage through the shutoff valve and is supplied toward the oxidant electrode.

Here, the flow resistance on the side of the diffuser chamber is determined by the diffused resistance when diffused in the liquid and the liquid depth at the diffused position, and the flow resistance of the shutoff valve is determined by the flow resistance of the diffuser liquid chamber. It is easy to make it sufficiently small.
The fuel cell system includes a recovery tank that recovers the liquid condensed from the humidified oxidant gas after passing through the oxidant electrode of the fuel cell body, a reforming liquid supply channel that supplies the reforming liquid from the recovery tank, A fuel reformer that receives the supply of the reforming liquid from the reforming liquid supply flow path and sends the fuel gas generated by reforming the raw fuel to the fuel supply flow path can be further provided. In this case, the fuel cell system is inserted into the coolant circulation channel, and circulates the coolant, branches from the reforming solution supply channel, and enters the coolant circulation channel immediately upstream of the pump. A replenishment flow path that is connected and replenishes the reforming liquid in the reforming liquid supply flow path as a cooling liquid, and is inserted in the reforming liquid supply path between the branch position of the replenishment flow path and the recovery tank, And a processor for processing the reforming liquid from the recovery tank into pure water. .

  According to the fuel cell system of the eleventh aspect, the reforming liquid is continuously supplied to the reforming liquid supply channel at a flow rate higher than the flow rate of the reforming liquid required for reforming the raw fuel. In this case, excess reforming liquid is supplied as a cooling liquid from the replenishing flow path to the cooling liquid circulation flow path. When the air circulation chamber of the humidifying tank is included in the cooling liquid circulation channel, the reforming liquid is replenished from the cooling liquid circulation channel to the air diffusion chamber as the humidifying liquid for the oxidant gas. Of the reforming liquid replenished to the diffuser liquid chamber in this manner, the liquid corresponding to the remaining consumed for humidifying the oxidant gas passes through the overflow weir and is discharged into the drain chamber.

Here, since the reformer supply flow path is inserted with a processor for processing the reformate from the recovery tank into pure water, the deionized water is in order of the required high purity, that is, fuel reforming. It supplies in order of an apparatus, a cooling fluid circulation flow path, and a diffused liquid chamber of a humidification tank.
Note that the drainage chamber can also be connected to the recovery tank of the reforming liquid supply flow path via a floating drainer.

  The present invention also provides an operation control method for the above-described fuel cell system. The operation control method of the present invention is performed between the oxidant gas flowing on the upstream side and the downstream side of the fuel cell body by the membrane type total heat exchanger. A step of humidifying the oxidant gas toward the fuel cell main body, and a step of dispersing the oxidant gas in the liquid in the humidification tank and humidifying the oxidant gas toward the fuel cell main body, These steps are switched and executed (claim 12).

The coolant supplied to the fuel cell main body is circulated through the fuel cell main body through one of the flow path including the humidification tank and the flow path bypassing the humidification tank, and the coolant toward the fuel cell main body is humidified. It is preferable that the temperature is raised by a heater outside the tank.
The fuel gas is generated by a fuel reformer that reforms the raw fuel, and the reforming liquid used for reforming the raw fuel is treated with pure water just before being supplied to the fuel reformer, and part of it is cooled. It is desirable to replenish as a liquid (Claim 14).

  The operation control methods of the above-described claims 12, 13, and 14 exhibit the same effects as the systems of claims 1, 7, and 11, respectively.

The fuel cell system and the operation control method thereof according to claims 1, 2, 8, and 12 use the humidification tank and the membrane-type total heat exchanger selectively, so that the whole system can be used by using a small humidification tank. The power consumption of the pump used for supplying the oxidant gas can also be reduced.
The fuel cell system according to claim 3 can easily control the liquid level of the diffuser chamber of the humidifying tank.

The fuel cell system according to claim 4 is provided with a hermetic coolant circulation passage in a part of the coolant supply passage, so that the coolant circulates in the coolant circulation passage so that the movement of the coolant is performed. Energy is stored, and the power consumption of the coolant pump that circulates the coolant can be reduced.
Since the fuel cell system according to claims 5 and 6 includes the air diffuser chamber of the humidifying tank in a part of the coolant supply channel, the liquid in the air diffuser chamber can be replenished as the coolant, At this time, since air bubbles are not mixed in the coolant, the suction capability of the coolant pump is not lowered.

The fuel cell system and the operation control method thereof according to claims 7 and 13 can simultaneously raise the temperature of the liquid in the fuel cell main body and the humidifying tank.
The fuel cell system according to claim 9 can be switched between the humidifying channel portion and the humidifying bypass channel in the oxidant supply channel only by using a single shutoff valve.
The fuel cell system and the operation control method thereof according to claims 10, 11 and 14 can maintain the pure water of the coolant supplied to the fuel cell main body at a high level, and can prevent the power generation performance of the fuel cell main body from deteriorating. .

1A and 1B schematically show an entire fuel cell system that implements the operation control method of the present invention.
[Fuel reformer]
FIG. 1A shows a fuel reformer 11 in the system, which will be described below.

The fuel reformer 11 includes a desulfurizer 11a, a reformer 11b, a CO converter 11c, and a CO selective oxidizer 11d, which are sequentially arranged from the left side as viewed in FIG. 1A. The desulfurizer and reformers 11a and 11b have a dedicated or shared combustion burner 11e.
A raw fuel path 1 extends from the desulfurizer 11a, and a fuel pump 5 and an electromagnetic fuel valve 2 are inserted into the raw fuel path 1 from the desulfurizer 11a side. The raw fuel path 1 supplies raw fuel of hydrocarbon gas such as city gas to the desulfurizer 11 a through the electromagnetic fuel valve 2 and the fuel pump 5.

  In the raw fuel path 1, a branch path 4 extends from a portion between the electromagnetic fuel valve 2 and the fuel pump 5, and this branch path 4 is connected to a combustion burner 11 e via a combustion fuel pump 6. Therefore, the raw fuel is also supplied to the combustion burner 11e. Further, an air path 8 is connected to the combustion burner 11e, and a combustion air pump 9 is inserted in the air path 8. The combustion air pump 9 supplies air to the combustion burner 11e. Therefore, the combustion burner 11e receives supply of the raw fuel and air, burns the raw fuel, and supplies the thermal energy to the desulfurizer 11a and the reformer 11b. The combustion exhaust gas generated by the combustion of the raw fuel is discharged from the combustion burner 11e through the exhaust gas path 33.

  Further, in the raw fuel path 1, a hydrogen supply path 7 for desulfurization is further branched from a portion between the branch position of the branch path 4 and the fuel pump 5, and the hydrogen supply path 7 is a CO converter. 11c. As will be described later, the CO converter 11 c generates intermediate gas containing hydrogen gas, and a part of the generated intermediate gas is returned to the suction side of the fuel pump 5 through the hydrogen supply path 7. Here, the return of the intermediate gas uses the differential pressure between the suction side of the fuel pump 5 and the CO transformer 11c, and this differential pressure determines the return amount of the intermediate gas. Note that the return amount of the intermediate gas can be adjusted by inserting an orifice or a throttle valve in the hydrogen supply path 7 and varying its opening.

Further, a branch path 16 is branched from the branch section 13 of the hydrogen supply path 7, and this branch path 16 is connected to the CO selective oxidation section 11d. A condensing path 12 extends from the branch portion 13, and a drainer 17 is inserted into the condensing path 12. The condensation path 12 is connected to a recovery path 96 (see FIG. 1B) described later.
A check valve 14 is inserted in the branch path 16, and the check valve 14 allows only a flow toward the CO selective oxidation unit 11d. Further, the branch path 16 has a merging portion 15 downstream of the check valve 14, and an air path 20 extends from the merging portion 15. An air pump 18 and a check valve 19 are inserted in the air path 20, and the air pump 18 supplies air toward the CO selective oxidation unit 11d.

Further, a reforming liquid supply channel 73 extends from the reformer 11b, and this reforming liquid supply channel 73 is connected to a reforming liquid supply device to be described later, and reforming made of pure water as the reforming liquid. Water is supplied to the reformer 11b.
As is clear from the above description, the fuel pump 5 mixes and raises the pressure of the raw fuel and the intermediate gas supplied to the suction side, and supplies these mixtures to the desulfurizer 11a. In the desulfurizer 11a, the sulfur energy is removed from the raw fuel by the heat energy from the combustion burner 11e and the hydrogen contained in the intermediate gas, and the desulfurized raw fuel is sent from the desulfurizer 11a to the next reformer 11b. . In the reformer 11b, water vapor is generated by evaporating the reformed water supplied from the reforming liquid supply channel 73 by receiving heat energy from the combustion burner 11e, and is thus supplied to the reformer 11b. The desulfurized fuel or hydrocarbon reacts with water vapor and is decomposed or reformed into hydrogen, carbon dioxide and carbon monoxide components. Therefore, the above-described cracking components, residual hydrocarbons and residual steam are simultaneously present in the reformer 11b, and these are fed into the next CO converter 11c. In the CO converter 11c, carbon monoxide reacts with residual water vapor, and the above-described intermediate gas in which decomposition of carbon monoxide into carbon dioxide and hydrogen is promoted, that is, an intermediate gas having a low component concentration of carbon monoxide is generated. Generated.

The intermediate gas is discharged from the CO transformer 11 c through the hydrogen supply path 7, and a part of the intermediate gas is returned to the suction side of the fuel pump 5 as described above, and the remainder is CO through the branch path 16 having the check valve 14. It is supplied to the selective oxidizer 11d. At this time, the reformed liquid condensed from the intermediate gas is separated by the drainer 17 and returned from the condensation path 12 to the recovery path 96.
Furthermore, since the air path 20 is connected to the junction 15 of the branch path 16, air is supplied to the CO selective oxidizer 11d by the air pump 18 in addition to the above-described intermediate gas. In the CO selective oxidizer 11d, carbon monoxide in the intermediate gas reacts with oxygen in the supply air to become carbon dioxide, and the intermediate gas in the CO selective oxidizer 11d further reduces the concentration of carbon monoxide, It is usually produced in fuel gas that does not exceed 10ppm.

A fuel supply passage 21 extends from the CO selective oxidizer 11d. The fuel supply passage 21 is connected to the fuel cell main body 25 shown in FIG. 1B and supplies fuel gas to the fuel cell main body 25.
[Fuel cell body]
In FIG. 1B, the fuel cell body 25 is shown as a single cell structure, and includes a fuel electrode (anode) 25a, an electrolyte membrane 25b, an oxidant electrode (cathode) 25c, a cooling unit 25d, and the like. The electrolyte membrane 25b is made of a fixed polymer (PEFC) sandwiched between the fuel electrode 25a and the oxidant electrode 25c, and the fuel cell body 25 is a so-called solid polymer cell stack.

  The fuel supply passage 21 of the fuel reformer 11 described above extends through the fuel electrode 25a and is connected to the combustion burner 11e of the fuel reformer 11. An electromagnetic shut-off valve 23 and a check valve 26 are inserted in the fuel supply passage 21 upstream and downstream of the fuel electrode 25a. The check valve 26 opens the fuel supply passage 21 only toward the combustion burner 11e. ing. The fuel supply passage 21 has a branch portion 22 upstream of the electromagnetic shut-off valve 23, and a bypass passage 27 is branched from the branch portion 22. The bypass passage 27 is located downstream of the check valve 26. The junction 28 is connected to the fuel supply passage 21. Further, an electromagnetic shut-off valve 24 is also inserted in the bypass flow path 27.

  When the fuel cell body 25 performs normal power generation, the electromagnetic shut-off valve 23 is opened, while the electromagnetic shut-off valve 24 is closed. In this case, the fuel supply passage 21 can supply a fuel gas containing hydrogen to the fuel electrode 25 a of the fuel cell body 25. However, when the concentration of carbon monoxide in the fuel gas is 10 ppm or more, the electromagnetic cutoff valve 23 is closed and the electromagnetic cutoff valve 24 is opened. In this case, the fuel gas in the fuel supply passage 21 flows through the bypass passage 27 without being supplied to the fuel electrode 25a. Therefore, the combustion gas is supplied to the fuel burner 11e, and is burned together with the raw fuel by the combustion burner 11e in order to obtain the thermal energy for reforming the raw fuel described above.

  During normal power generation, hydrogen in the fuel gas supplied to the fuel electrode 25a becomes hydrogen ions by the action of the catalyst of the fuel electrode 25a, and the hydrogen ions pass through the electrolyte membrane 25b and move to the oxidant electrode 25c. . And the hydrogen ion which reached | attained the oxidant electrode 25c reacts with the oxygen in the air as the oxidant supplied to the oxidant electrode 25c by the action of the catalyst of the oxidant electrode 25c to generate water.

  In order to humidify the electrolyte membrane 25b, the fuel gas is usually required to be humidified. However, as is clear from the above explanation, the combustion gas contains unreacted water vapor. Further, humidification of the combustion gas is achieved by introducing the combustion gas to the fuel electrode 25a without condensing the water vapor, so that it is not necessary to separately insert a humidifier for the combustion gas in the fuel supply passage 21. .

The supply of the oxidant, that is, the air to the oxidant electrode 25c will be described later.
Along with the reaction in the fuel cell main body 25 described above, a current flows from the fuel electrode 25a to the oxidant electrode 25c through the power conditioner (not shown) as an external load. Electric power can be taken out from the battery body 25. Further, the electrochemical reaction in the fuel cell body 25 involves heat generation proportional to the amount of power generation, and the heat generation amount is usually large enough to be comparable to the power generation amount.

On the other hand, the fuel supply passage 21 further has a branch portion 30 downstream of the junction portion 28, and the recovery path 96 described above extends from the branch portion 30. The recovery path 96 is connected to the recovered water layer 75 and has a drainer 32 in the vicinity of the branch portion 30. Therefore, the drainer 32 removes the condensed water in the fuel gas before the combustion gas after passing through the fuel electrode 25a and the fuel gas flowing through the bypass passage 27 are guided to the combustion burner 11e. The condensed water is recovered from the drainer 32 through the recovery path 96 to the recovery water tank 75. The recovered water tank 75 will be further described later.
[Oxidant supply]
As shown in FIG. 1B, the oxidant electrode 25c of the fuel cell body 25 is inserted in the middle of an air supply channel 40 as an oxidant supply channel. The air supply flow path 40 includes an upstream air flow path 42 located upstream of the oxidant electrode 25c and a downstream air flow path 50 located downstream of the oxidant electrode 25c. The recovered water tank 75 is connected.

An air pump 41 is inserted upstream of the upstream air flow path 42, and the air pump 41 supplies air toward the oxidant electrode 25c. In addition, an initial humidification tank 45 is inserted downstream of the air pump 41 in the upstream air flow path 42.
Details of the Initial Humidification Tank 45 Specifically, the initial humidification tank 45 includes a sealed tank main body 44, and an overflow weir 45 a is disposed in the tank main body 44. The overflow weir 45a divides the inside of the tank main body 44 into an aeration liquid chamber 47 and a drainage chamber 45c. In the diffuser chamber 47, water as a reforming solution is stored, and an diffuser plate 45b is horizontally disposed in this solution. The diffuser plate 45b is formed of a perforated plate and is connected to the lower end of the diffuser tube 45g. The air diffuser 45g extends upward from the air diffuser plate 45b, passes through the ceiling wall of the tank main body 44 in an airtight manner, and is connected to the portion of the upstream air flow path 42 on the air pump 41 side, that is, the air introduction portion 42a. .

Therefore, the air supplied by the air pump 41 through the upstream air flow path 42 is supplied to the diffuser tube 45g of the initial humidification tank 45, and is diffused as bubbles from the diffuser plate 45b into the liquid in the diffuser liquid chamber 47. It is humidified by this aeration. Thereafter, the bubbles rise in the liquid and flow into the gas phase portion of the diffuser liquid chamber 47.
On the other hand, an air outlet portion 42b of the upstream air flow path 42 located downstream of the initial humidifying tank 45 is connected to the gas phase portion of the diffuser chamber 47, and this air outlet portion 42b communicates with the gas phase portion. With open ends. Accordingly, since the tank body 44 has a sealed structure, the humidified air flows out from the gas phase portion of the diffuser liquid chamber 47 through the air outlet portion 42b.

  Here, as will be apparent from the following description, the diffuser chamber 47 is continuously supplied with water, and the liquid in the diffuser chamber 47 passes over the overflow weir 45a and is constantly discharged into the drain chamber 45c. It is in a state that has been. This means that the liquid level in the diffuser liquid chamber 47 always coincides with the upper edge of the overflow weir 45a, and the liquid depth from the liquid level to the diffuser plate 45b is maintained constant. In other words, the initial humidification tank 45 exhibits stable humidification performance.

  A bubble breaker plate 45 f is disposed in the gas phase portion of the diffuser liquid chamber 47, and the bubble breaker plate 45 f is interposed between the open end of the air outlet portion 42 b and the liquid level of the diffuser liquid chamber 47. And attached to the diffuser tube 45g. Even if water droplets are scattered from the liquid surface of the diffuser liquid chamber 47 toward the opening end of the air outlet portion 42b, the bubble breaker plate 45f can prevent the water droplets from flowing into the humidified air flowing out through the air outlet portion 42b. Make sure to prevent contamination.

  Further, it is desirable that a diffuser plate 45e is provided in the diffuser liquid chamber 47, and this wave suppressor plate 45e is disposed between the diffuser tube 45g and the overflow weir 45a. In addition, a liquid level gauge 45d is attached to the outside of the tank body 47 as necessary, and the upper and lower ends of the liquid level gauge 45d are connected to the gas phase portion and the liquid portion of the diffuser liquid chamber 47 through connection pipes, respectively. Communicate.

A drainage path 51 extends from the bottom of the drainage chamber 45c described above, and the drainage path 51 is connected to the recovery path 96 described above. A float type drainer 46 is inserted in the drainage path 51, and details of the drainer 46 are shown in FIG.
The drainer 46 has a float 46a in its casing and a discharge valve 46b that is opened and closed by raising and lowering the float 46a. When a certain amount of water led from the drain chamber 45c into the drain 46 accumulates, the float 46a floats and opens the drain valve 46b. At this point, the liquid in the drain 46 is temporarily drained through the drain valve 46b. . Thereafter, when the float 46a is lowered and the discharge valve 46b is closed again, the discharge of water is stopped. Since such a float type drainer 46 is in a state in which water is constantly stored therein, air in the initial humidification tank 45 is not released outside through the drainer 46.

Furthermore, a drain path 52 extends from the bottom of the diffuser chamber 47, and a manual ball valve 52 a is inserted in the drain path 52.
On the other hand, in the upstream air flow path 42 of the air supply flow path 40, the part 42 c and the downstream air flow path 50 downstream of the air outlet portion 42 b described above pass through the membrane type total heat exchanger (membrane type steam exchanger) 49. And extended. The membrane type total heat exchanger 49 can exchange heat and steam between the air toward the oxidant electrode 25c and the air after passing through the oxidant electrode 25c.

Regarding Membrane Total Heat Exchanger Specifically, the membrane used for the membrane total heat exchanger 49 has a structure in which a main chain of a Teflon (trade name) skeleton is provided with a sulfone group as a side chain. Here, the main chain exhibits water repellency, while the sulfone group, which is a side chain, exhibits hydrophilicity. Therefore, the film has an agglomerated structure in which the water repellent part and the hydrophilic part are independent, and the hydrophilic part has The taken-in water can be moved freely.

  The membrane-type total heat exchanger 49 uses the above-described membrane function, and flows high-humidity water vapor or water on one side across the membrane, and dry air or oxidant on the other side. By flowing, water movement occurs through the membrane based on the partial pressure difference of water vapor. Therefore, while the moisture content of the dry air or oxidant increases, the moisture content of the high-humidity steam or liquid water decreases and heat and steam are exchanged across the membrane.

Specifically, the membrane-type total heat exchanger 49 uses a hollow fiber as a membrane, flows air toward the oxidant electrode 25c through the inside of the hollow fiber, and passes through the oxidant electrode 25c through the outside of the hollow fiber. It is configured to flow air.
Further, a humidification bypass flow path 48 that bypasses a portion (humidification flow path portion) including the initial humidification tank 45 is branched from the upstream air flow path 42 of the air supply flow path 40, and the humidification bypass flow path 48 is electromagnetically blocked. A valve 43 is inserted. When the electromagnetic shut-off valve 43 is closed, the air supplied from the air pump 41 flows through the initial humidification tank 45 without passing through the humidification bypass passage 48. On the other hand, when the electromagnetic shut-off valve 43 is opened, the flow resistance of the humidification bypass flow path 48 including the electromagnetic shut-off valve 43 is sufficiently smaller than the flow resistance on the diffuser liquid chamber 47 side of the initial humidification tank 45. The air supplied from the air pump 41 does not go to the initial humidification tank 45, but the entire amount passes through the humidification bypass passage 48, that is, the electromagnetic shut-off valve 43, the membrane type total heat exchanger 49, and the oxidation of the fuel cell body 25. It is supplied to the agent electrode 25c. Therefore, the electromagnetic shut-off valve 43 and the humidification bypass flow path 48 constitute a separating means for selectively separating the initial humidification tank 45 from the air supply flow path 40, and the electromagnetic shut-off valve 43 comprises the humidification flow path portion and the humidification bypass flow path. It becomes the humidification switching means which opens one of 48.

  The flow path resistance on the diffused liquid chamber 47 side will be described in detail. The flow path resistance includes the diffused resistance when air is diffused from the diffuser plate 45b and the liquid from the diffuser plate 45b to the liquid level. It is expressed as the sum of the bubble passage resistance determined by the depth. If the liquid depth is not sufficiently secured to reduce the size of the initial humidification tank 45, an orifice, a throttle, or the like is inserted into the portion 42a of the upstream air flow path 42 or the air diffuser 45g. The flow resistance on the gas-liquid chamber 47 side may be made larger than the flow resistance of the electromagnetic shut-off valve 43.

Regarding the initial humidification, the air pump 41 of the air supply passage 40 described above is supplied toward the oxidant electrode 25c of the fuel cell body 25 from a predetermined time before the start of power generation in the fuel cell body 25. The shut-off valve 43 is closed. For this reason, all the air in the air supply flow path 40 is diffused in the liquid of the diffused liquid chamber 47 in the initial humidifying tank 45 and passes through the diffused liquid chamber 47 and is humidified at this time.

  The air thus humidified passes through the membrane type total heat exchanger 49 and passes through the oxidant electrode 25c of the fuel cell main body 25 to humidify the oxidant electrode 25c, that is, the electrolyte membrane 25b. Thereafter, the passing air that has passed through the oxidant electrode 25c is discharged to the recovered water tank 75 through the downstream air flow path 50 of the air supply flow path 40 and the membrane type total heat exchanger 49. The heat exchanger 49 performs steam exchange between the humidified air toward the oxidant electrode 25c and the passing air from the oxidant electrode 25c. After the initial humidification of the electrolyte membrane 25b (oxidant electrode 25c) reaches a steady state, the dew point difference between the humidified air and the passing air becomes slight.

Since the main role of the initial humidification described above is to prehumidify the membrane of the electrolyte membrane 25b and the membrane type total heat exchanger 49, high efficiency is not required for humidification with respect to air. The tank 45 can be downsized.
Note that a bypass flow path that bypasses the membrane total heat exchanger 49 may be further provided in the downstream air flow path 50 so that air passing from the oxidant electrode 25c flows through the bypass flow path during initial humidification.

Regarding humidification during power generation After this, after the elapse of the predetermined time described above, that is, when preliminary humidification for the electrolyte membrane 25b and the membrane type total heat exchanger 49 is completed, the electromagnetic shut-off valve 43 is closed, and the fuel cell body 25 Fuel gas is supplied to the fuel electrode 25a, and the fuel cell main body 25 starts power generation.
After the power generation of the fuel cell body 25, all the air from the air pump 41 is supplied to the oxidant electrode 25c through the membrane total heat exchanger 49, bypassing the initial humidification tank 45, and the oxidant electrode 25c. After passing through, the membrane type total heat exchanger 49 is again passed to the recovered water tank 75.

After the start of power generation, water and heat generated by power generation are generated in the oxidant electrode 25c, so that the passing air passing through the oxidant electrode 25c is sufficiently humidified by the generated water and rises. It is in a heated state. Therefore, in the membrane total heat exchanger 49, steam exchange and heat exchange are performed between the supply air toward the oxidant electrode 25c and the passing air, and the supply air is humidified and heated well. The
[Cooling water supply]
As shown in FIG. 1B, the cooling unit 25 d of the fuel cell main body 25 is disposed in the coolant supply channel 60. The coolant supply channel 60 has a coolant pump 62, and the coolant pump 62 circulates coolant through the coolant supply channel 60. In the coolant supply channel 60, a check valve 64 and a heater 63 are inserted between the discharge side of the coolant pump 62 and the cooling unit 25d. The check valve 64 and the heater 63 are on the coolant pump 62 side. Are arranged sequentially. An air vent valve 65, an electromagnetic shut-off valve 66, and a diffused liquid chamber 47 of the initial humidification tank 45 are inserted in the coolant supply channel 60 between the cooling unit 25d and the suction side of the coolant pump 62, These air vent valve 65, electromagnetic shut-off valve 66, and diffused liquid chamber 47 are sequentially arranged from the cooling unit 25d side. Here, it goes without saying that the air vent valve 65 is positioned at the uppermost position of the coolant supply channel 60.

Therefore, the cooling liquid supply channel 60 includes a diffused liquid chamber 47 in a part thereof. Specifically, the diffused liquid chamber 47 has an inlet 60 a and an outlet 60 b for the cooling liquid supply channel 60, respectively. 60a and outlet 60b are positioned below diffuser plate 45b.
Further, the coolant supply flow path 60 has a branch portion 69a between the air vent valve 65 and the electromagnetic shut-off valve 66 when viewed in the flow direction of the coolant, and the cooling bypass flow path 60c is branched from the branch portion 69a. Yes. This cooling bypass flow path 60c is connected to the cooling liquid supply flow path 60 at a junction 69b between the suction side of the cooling liquid pump 62 and the diffused liquid chamber 47, and an electromagnetic cutoff valve 67 is interposed in the middle. It is inserted. The electromagnetic shut-off valve 67 and the aforementioned electromagnetic shut-off valve 66 constitute cooling switching means for switching the flow of the coolant to the diffuser liquid chamber 47 side or the cooling bypass flow path 60c side.

Regarding Initial Temperature Raising The coolant pump 62 is driven in conjunction with the air pump 41 described above prior to the power generation of the fuel cell body 25 and circulates the coolant through the cooling portion 25d of the fuel cell body 25. At this time, the heater 63 is energized to raise the temperature of the coolant toward the cooling unit 25d, whereby the cooling unit 25d, that is, the fuel cell main body 25 (electrolyte membrane 25b) is initially heated.

Further, during the initial temperature increase, only the electromagnetic shut-off valve 66 is opened for the electromagnetic shut-off valves 66 and 67. Therefore, the heated coolant is circulated in the coolant supply flow channel 60 through a portion (cooling flow channel portion) including the diffused liquid chamber 47 of the initial humidifying tank 45, thereby the diffused liquid chamber. 47 water is also heated.
Therefore, with respect to the initial humidification of the air described above, since the water heated in the diffuser liquid chamber 47 is used, not only the humidification effect on the air is further improved, but also the oxidant electrode 25c. Since the temperature of the supplied air is also raised, the initial temperature rise of the fuel cell body 25 (electrolyte membrane 25b) is efficiently performed.

In addition, the coolant circulating through the diffuser chamber 47 is pressurized by the pressure of the gas phase portion of the diffuser chamber 47, so even if air is mixed in the coolant supply channel 60, this mixture The air is easily exhausted from the air vent valve 65, and the water in the diffuser liquid chamber 47 is replenished as cooling water into the coolant supply circulation channel 60 by the amount of this exhaust.
Regarding the power generation of the fuel cell main body When the power generation of the fuel cell main body 25 is started, the energization to the heater 63 is stopped, and the electromagnetic cutoff valve 67 is closed while the electromagnetic cutoff valve 67 is opened. In this case, the cooling liquid bypasses the diffused liquid chamber 47 of the initial humidifying tank 45 and circulates in the cooling liquid supply flow path 60 in the circulation flow path formed including the cooling bypass flow path 60c. 25d, that is, the fuel cell body 25 is cooled.

Regarding the temperature rise and cooling described above, the temperature management of the fuel cell main body 25 controls the energization of the heater based on the inlet temperature and / or outlet temperature of the coolant with respect to the cooling section 25d, and also controls the discharge flow rate of the coolant pump. It is implemented by varying.
As described above, during power generation of the fuel cell main body 25, the coolant supply flow path 60 is a completely closed hermetic loop pipe line (cooling liquid circulation flow path) that does not include the diffused liquid chamber 47 of the initial humidifying tank 45. Therefore, the circulating kinetic energy of the coolant is stored in the coolant supply flow path 60, and the power consumption of the coolant pump 62 can be greatly reduced.

In addition, the heater 63 used for the initial temperature rise of the cooling liquid can be disposed in the liquid in the diffuser liquid chamber 47 of the initial humidifying tank 45, but as described above, the heater 63 is provided in the cooling liquid supply channel 60. By interposing, the initial humidification tank 45 can be further reduced in size.
[Reforming liquid supply device]
As is apparent from FIG. 1B, the reforming liquid supply apparatus for supplying the above-described reforming liquid includes a recovery water tank 75 connected to the reforming liquid supply flow path 73, and the water in the recovery water tank 75 is modified. It is supplied to the reformer 11b of the fuel reformer 11 as quality water. Therefore, a supply water pump 76 is inserted in the vicinity of the recovered water tank 75 in the reforming liquid supply channel 73, and the reforming water is provided downstream of the supply water pump 76, that is, on the reformer 11b side. A pump 72 is inserted.

  Further, a check valve 77 and a water treatment device 78 are inserted in the reforming liquid supply flow path 73 between the makeup water pump 76 and the reforming water pump 72, and these check valve 77 and water treatment device 78. Are sequentially arranged from the makeup water pump 76 side. The water treatment device 78 purifies the water discharged from the makeup water pump 76 and sends it to the reforming water pump 72 as pure water reforming water whose electrical conductivity is lowered.

Further, the reforming liquid supply channel 73 has a branch portion 71 between the water treatment device 78 and the reforming water pump 72, and a replenishment channel 79 is branched from the branch portion 71. The replenishing flow path 79 is connected to a merging portion 61 positioned between the merging portion 69 b and the cooling liquid pump 62 with respect to the cooling liquid supply flow path 60 described above.
The makeup water pump 76 described above discharges a required amount of reforming water required by the reformer 11 b, that is, a larger amount of water than the discharge flow rate of the reforming water pump 72. Therefore, since the reforming water pump 72 is supplied with more reforming water than the required amount, the excess reforming water is replenished to the coolant supply channel 60 through the supply channel 79 as a coolant. The Further, the reformed water replenished in this way flows into the diffuser liquid chamber 47 of the initial humidification tank 45, so that the amount of liquid in the diffuser liquid chamber 47 increases.

  However, since the overflow weir 45a is provided in the diffuser liquid chamber 47, the amount of liquid in the diffuser liquid chamber 47 is increased by the amount exceeding the overflow weir 45a from the diffuser liquid chamber 47 to the drain chamber 45c. Then, the liquid is discharged, and the liquid depth of the diffused liquid chamber 47 is maintained constant. As described above, the drainage in the drainage chamber 45 c is collected in the collection water tank 75 through the float drainer 46.

  As is clear from the above description, the pure water treated by the water treatment device 78 is in the order in which the degree of purity is high, that is, the reforming water for the reformer 11b and the cooling of the coolant supply channel 60. The liquid and the humidified water in the diffuser liquid chamber 47 are supplied or replenished in this order. Therefore, the electrical conductivity of the water in the coolant and the oxidant gas can be kept small, and the power generation efficiency of the fuel cell body 25 can be prevented from deteriorating.

Needless to say, the supply amount of the reforming liquid to the cooling liquid supply flow path 60 is increased or decreased according to the degree of contamination of the cooling liquid.
Details of the recovered water tank As is clear from FIG. 1B, the recovered water tank 75 is connected to a public water supply (city water) system via a water supply line 70, and an electromagnetic shut-off valve 74 is inserted in the water supply line 70. . In the recovered water tank 75, an overflow weir 75a is provided as in the case of the initial humidifying tank 45 described above, and this overflow weir 75a defines a drainage chamber 75b in the recovered water tank 75, and the amount of water in the recovered water tank 75 Is kept constant. A drain pipe 75c extends from the bottom of the drain chamber 75b, and the gas phase portion of the recovered water tank 75 is opened to the atmosphere through the exhaust pipe 75e.

  Further, the recovery water tank 75 is provided with a liquid level gauge 75d, and this liquid level gauge 75d is used for controlling the opening and closing of the electromagnetic shut-off valve 74. Specifically, when the liquid level gauge 75d detects a high water level (H) lower than the overflow weir 75a, the electromagnetic shut-off valve 74 is closed, whereas the liquid level gauge 75d detects a low water level (L). When this occurs, the electromagnetic shut-off valve 74 is opened, and city water is replenished into the recovered water tank 75.

  As described above, the recovery path 96 to the recovery water tank 75 is branched from the fuel supply passage 21 to the fuel cell main body 25, and the condensation path 12 is branched to the recovery path 96 from the hydrogen supply path 7 of the fuel reformer 11. In addition, a drainage path 51 extending from the initial humidification tank 45 is connected. Therefore, the water condensed from the combustion gas flowing in the fuel supply passage 21, the water condensed from the intermediate gas flowing in the hydrogen supply path 7, and the water discharged from the initial humidification tank 45 are recovered water tanks as recovered water. 75 is recovered. When the amount of the recovered water is large, excess water in the recovered water tank 75 passes through the overflow weir 75a and is discharged through the drainage chamber 75b.

Since the pure water level (electrical conductivity) of the recovered water is higher than that of city water, the life of the water treatment device 78 can be extended by reusing the recovered water, and also contributes greatly to saving of city water charges. To do.
[Heat recovery device]
The heat recovery device includes a heat exchanger 53 inserted downstream of the membrane total heat exchanger 49 in the downstream air passage 50 of the air supply passage 40 described above, and a fuel supply flow of the fuel cell main body 25. A heat exchanger 29 inserted between the junction 28 and the branch 30 in the passage 21, a heat exchanger 34 inserted in the exhaust gas path 33 extending from the combustion burner 11 e of the fuel reformer 11, and A heat exchanger 68 interposed in the cooling bypass channel 60c of the coolant supply channel 60 is provided.

  On the other hand, a heat recovery path 89 extends through the heat exchangers 53, 29, 34, and 68 described above, and this heat recovery path 89 forms a flow path of heat recovery water and passes through the water heater 100. A heat recovery pump 83 is inserted in the heat recovery path 89 between the heat exchanger 53 and the water heater 100, and the heat recovery water discharged from the heat recovery pump 83 is used as the heat exchangers 53, 29, 34, 68. In this order, it passes through these heat exchangers and reaches the water heater 100.

  Therefore, during the power generation of the fuel cell main body 25 described above, the heat energy generated by this power generation is the humidified air flowing through the downstream air flow path 50 of the air supply flow path 40, the fuel electrode 25a of the fuel cell main body 25, and the cooling unit. The fuel gas and the coolant that have respectively passed through 25d are recovered by heat exchange with the heat recovery water in the heat exchangers 53, 29, and 68, and the exhaust gas from the combustion burner 11e of the fuel reformer 11 is heat exchanged. It is recovered by exchanging heat with the heat recovery water in the vessel 34, thereby achieving a temperature increase of the heat recovery water.

The arrangement of the heat exchangers 53, 29, 34, and 68 in the heat recovery path 89 is not limited to that shown in the figure, and the order of the heat exchanger through which the heat recovery water passes is such that the heat recovery efficiency is the highest. Selected.
As is clear from the above description, when the fuel cell main body 25 generates power, the coolant supply flow path 60 forms a closed circulation flow path including the cooling bypass flow path 60c, so that heat generated from the fuel cell main body 25 is generated. The energy is not consumed for raising the temperature of the liquid in the initial humidifying tank 45, that is, the humidified water, and the heat energy is efficiently recovered by the heat exchanger 68 into the heat recovery water.

Similarly, during the power generation of the fuel cell main body 25, the humidified air flowing through the downstream air flow path 50 of the air supply flow path 40 is also not consumed for increasing the temperature of the humidified water in the initial humidification tank 45. The heat energy is efficiently recovered in the heat recovery water by the heat exchanger 53.
In the heat recovery path 89, an air vent valve 88 is inserted at a portion between the heat exchanger 68 and the water heater 100. The air vent valve 88 only needs to be disposed at the uppermost position of the heat recovery path 89, and the position of the air vent valve 88 is not limited to the above-described part.

On the other hand, a normally open electromagnetic shut-off valve 92 and a radiator 93 are inserted from the water heater 100 side into a portion of the heat recovery path 89 connecting the water heater 100 and the suction side of the heat recovery pump 83, and these electromagnetic A bypass path 94 that bypasses the shut-off valve 92 and the radiator 93 is provided, and a normally-closed electromagnetic shut-off valve 95 is inserted in the bypass path 94.
Further, a confluence portion 81 is provided at a portion of the heat recovery path 89 on the suction side of the heat recovery pump 83, and this confluence portion 81 is connected to the above-described recovery path 96 via a connection path, and is non-returned to this connection path. A valve 82 is inserted. The check valve 82 can be opened only toward the heat recovery path 89.

  As is clear from FIG. 1B, the part of the recovery path 96 from the heat recovery pump 83 and / or the junction 81 to the recovered water tank 75 via the connection path is disposed below the liquid level in the recovered water tank 75. Thereby, even if the air mixed in the heat recovery path 89 is exhausted through the air vent valve 88, water is automatically supplied into the heat recovery path 89 from the recovered water tank 75 side with the exhaust. Therefore, since the heat recovery path 89 forms a closed circulation path, the power consumption of the heat recovery pump 83 can be reduced.

The discharge amount of the heat recovery pump 83, that is, the circulation amount of the recovered water can be controlled by, for example, the inlet temperature of the coolant flowing into the cooling unit 25d of the fuel cell body 25.
Further, the moisture condensed from the fuel gas in the heat exchanger 29 and the moisture condensed from the humidified air in the heat exchanger 53 are also recovered in the recovery water tank 75 as is apparent from the above description.
Details of the Water Heater As shown in FIG. 3, the water heater 100 includes a hot water storage tank 101, and a heat exchanger 101 a interposed in the heat recovery path 89 is disposed in the hot water storage tank 101. A water supply pipe 101c extends from the bottom of the hot water tank 101, and a manual ball valve 104 is inserted into the water supply pipe 101c. The water supply pipe 101c is connected to a city water system via a connection pipe 103 at a portion between the hot water storage tank 101 and the ball valve 104, and the hot water storage tank 101 can receive supply of city water.

On the other hand, an air vent valve 101b is attached to the top of the hot water storage tank 101, and a hot water supply service pipe 105 extends from the top. A hot-burning burner 102 is inserted into the hot-water supply service pipe 105 as necessary, and the hot-burning burner 102 can be ignited by receiving supply of city gas.
The city water supplied into the hot water storage tank 101 is heated by heat exchange with the heat recovery water in the heat exchanger 101a, and then supplied to hot water through the hot water supply service pipe 105.

It is the figure which showed the fuel reformer which is a part of fuel cell system. It is the figure which showed the remainder of the fuel cell system. It is sectional drawing which showed the float-type drainer in FIG. 1B. It is the figure which showed the detail of the water heater in FIG. 1B.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Fuel reformer 21 Fuel supply flow path 25 Fuel cell main body 29, 34 Heat exchanger 40 Air supply flow path (oxidant supply flow path)
43 Electromagnetic shut-off valve 44 Tank body 45 Initial humidification tank 45a Overflow weir 45b Aeration plate (aeration position)
45c Drainage chamber 45g Diffuser pipe 46 Float drainer 47 Diffuser liquid chamber 48 Humidification bypass flow path 49 Membrane total heat exchanger 53 Heat exchanger 60 Coolant supply flow path 60a Inlet 60b Outlet 60c Cooling bypass flow path 62 Cooling liquid Pump 63 Heater 66, 67 Electromagnetic shut-off valve (cooling switching means)
68 Heat exchanger 72 Reformed water pump 73 Reforming liquid supply flow path 75 Recovery water tank 76 Replenishment water pump 78 Water treatment device 79 Replenishment flow path 89 Heat recovery path 100 Water heater 101 Hot water storage tank 101a Heat exchanger

Claims (14)

A fuel cell body;
A fuel supply passage for supplying fuel gas to the fuel cell body;
Supplying an oxidant gas to the fuel gas through the fuel cell main body, and an oxidant supply flow path having upstream and downstream portions respectively positioned upstream and downstream of the fuel cell main body;
A coolant supply passage for supplying a coolant through the fuel cell body;
A membrane-type total heat exchanger for exchanging heat and steam between oxidant gases flowing in an upstream part and a downstream part of the oxidant supply flow path,
A humidifying tank that is inserted in an upstream portion of the oxidant supply flow path, diffuses the oxidant gas into the liquid, and sends the humidified oxidant gas toward the fuel cell body;
A fuel cell system comprising a separation means provided at an upstream portion of the oxidant supply channel and capable of selectively separating the humidification tank from the upstream portion.   The fuel cell system according to claim 1, wherein the humidifying tank is disposed upstream of the all-film heat exchanger. The humidifying tank is
A sealed tank body,
A diffused liquid chamber provided in the tank body, storing the liquid and having a diffused position of the oxidant gas positioned in the liquid;
A drainage chamber adjacent to the diffuser chamber is defined in the tank body, and excess liquid in the diffuser chamber is allowed to escape to the drainage chamber, so that the diffuser can be removed from the liquid level of the diffuser chamber. An overflow weir that determines the liquid depth to the air position;
The fuel cell system according to claim 1, further comprising a float-type drainer that discharges the liquid in the drainage chamber.   The fuel cell system according to any one of claims 1 to 3, wherein the coolant supply channel includes a sealed coolant circulation channel in a part thereof.   5. The fuel cell system according to claim 4, wherein the coolant supply flow path includes the diffused liquid chamber of the humidification tank in a part thereof.   6. The fuel cell system according to claim 5, wherein the diffused liquid chamber has an inlet and an outlet positioned below a diffused position in the liquid for connection to the coolant supply flow path. . The coolant supply channel is
A cooling flow path portion including the diffuser chamber;
A cooling bypass passage extending in parallel with the cooling passage portion;
In the cooling liquid supply flow path, a heater inserted other than the cooling bypass flow path,
The fuel cell system according to any one of claims 4 to 6, further comprising cooling switching means for opening one of the cooling channel portion and the cooling bypass channel and closing the other. The separating means includes
A humidification bypass flow path provided in an upstream portion of the oxidant supply flow path and extending in parallel with a humidification flow path portion including the diffused liquid chamber;
8. The fuel cell system according to claim 1, further comprising a humidification switching unit that opens one of the humidification flow path portion and the humidification bypass flow path and closes the other. The humidification switching means includes an openable / closable shut-off valve inserted in the humidification bypass flow path,
9. The fuel cell system according to claim 8, wherein when the shut-off valve is opened, the shut-off valve has a channel resistance that is smaller than the channel resistance on the diffuser liquid chamber side and allows the entire flow rate of the oxidant gas to pass therethrough. . A recovery tank for recovering the liquid condensed from the humidified oxidant gas after passing through the oxidant electrode of the fuel cell body;
A reforming liquid supply flow path for supplying a reforming liquid from the recovery tank;
A fuel reformer that receives the reformate from the reformate supply channel and sends the fuel gas generated by reforming the raw fuel to the fuel supply channel; The fuel cell system according to any one of claims 4 to 9. A pump that is inserted into the coolant circulation channel and circulates the coolant;
A replenishing flow path that branches from the reforming liquid supply flow path and is connected to the cooling liquid circulation flow path immediately upstream of the pump and replenishes the reforming liquid in the reforming liquid supply flow path as the cooling liquid. When,
It further includes a processor that is inserted in the reforming liquid supply path between the branch position of the replenishing flow path and the recovery tank and processes the reforming liquid from the recovery tank into pure water. The fuel cell system according to claim 10. In the fuel cell system in which the fuel gas is supplied to the fuel cell main body, and the oxidant gas and the coolant for the fuel gas are respectively supplied through the fuel cell main body.
A step of humidifying the oxidant gas toward the fuel cell main body between the oxidant gas flowing upstream and downstream of the fuel cell main body by a membrane total heat exchanger; and in the liquid in the humidification tank A process of aspirating the oxidant gas and humidifying the oxidant gas toward the fuel cell main body,
An operation control method for a fuel cell system, wherein the steps are switched and executed.   The coolant is circulated through the fuel cell main body through one of a flow path including the humidification tank and a flow path bypassing the humidification tank, and the coolant toward the fuel cell main body is heated outside the humidification tank. The fuel cell system operation control method according to claim 12, wherein the temperature is raised by the operation.   The fuel gas is generated by a fuel reforming device that reforms the raw fuel, and the reforming liquid used for reforming the raw fuel is treated with pure water immediately before being supplied to the fuel reforming device. The fuel cell system operation control method according to claim 12 or 13, wherein the coolant is replenished as the coolant.

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