JP6376786B2 - Fuel cell system - Google Patents

Description

The present invention includes a fuel cell module that houses therein a fuel cell unit that generates electricity by reacting fuel gas and air, and discharges exhaust gas from the fuel cell unit;
A condensed water generating unit for condensing water vapor contained in the exhaust gas discharged from the fuel cell module to generate condensed water and discharging the condensed water downward;
The present invention relates to a fuel cell system in which a condensate discharged from the condensate generator and a water tank having a tank drain that drains the stored water are disposed in a casing.

As a conventional fuel cell system, in a casing, a fuel tank that stores therein a water tank that stores condensed water discharged from a condensed water generation unit, and a fuel cell unit that generates electricity by reacting fuel gas and air. The thing arrange | positioned under the battery module is known (for example, refer patent document 1).
Thus, in the fuel cell system in which the water tank is arranged below the fuel cell module, the tank drainage unit that drains the water tank is arranged near the bottom of the casing.
Further, in such a conventional fuel cell system, particularly a fuel cell system including a solid oxide fuel cell unit that operates at a high temperature, the fuel cell module is kept at a relatively high temperature, so that the casing is excessive. In some cases, the temperature rises to an inconvenience in handling by the user or operation of internal devices. Therefore, in order to suppress such excessive temperature rise of the housing, a ventilation fan for ventilating the inside of the housing may be provided.

JP 2010-272305 A

In the conventional fuel cell system as described above, since the water tank is disposed below the fuel cell module, it is located near the bottom of the housing with respect to the drain port provided at the installation location of the fuel cell system. As a result, the height of the tank drainage portion disposed was lowered, and as a result, the head pressure required for good drainage could not be obtained.
In such a case, the fuel cell system is installed on a dedicated platform and the height of the tank drainage is raised. However, the addition of the dedicated platform increases the cost and improves the design. There were problems such as deterioration.
Further, when a ventilation fan is provided to suppress an excessive temperature rise in the casing of the fuel cell system, a problem of noise due to the operating sound of the ventilation fan occurs. In particular, noise is increased when the ventilation fan is externally attached to the outside of the housing which is not easily affected by heat, or when the ventilation fan is operated at the maximum output during the summer heat.

  Therefore, the present invention has been made paying attention to such a point, and the object thereof is to improve the drainage from the tank drainage section that drains the water tank that stores the condensed water in the fuel cell system. This is in providing a technique capable of suppressing excessive temperature rise in the housing.

In order to achieve this object, a fuel cell system according to the present invention comprises:
A fuel cell module that houses therein a fuel cell unit that generates electricity by reacting fuel gas and air, and discharges exhaust gas from the fuel cell unit;
A condensed water generating unit for condensing water vapor contained in the exhaust gas discharged from the fuel cell module to generate condensed water and discharging the condensed water downward;
A fuel cell system in which a water tank having a tank drainage section for storing the condensed water discharged from the condensed water generation section and draining the stored water is disposed in a housing,
Its feature configuration is
The water tank is disposed above the fuel cell module;
A water pump for sending the condensed water discharged from the condensed water generation unit to the water tank;
The water supply pipe line to the water tank by the water pump is configured as a water cooling part that cools at least a part to be cooled on the peripheral side surface of the housing by heat exchange with water supply ,
A reformer for steam reforming the fuel gas and supplying it to the fuel cell unit, and a steam generator for heating the feed water and generating steam to be supplied to the reformer are provided inside the fuel cell module. Contained,
A water supply conduit for guiding water stored in the water tank to the steam generator by its own weight ;
A water purifier that is disposed below the fuel cell module and temporarily stores the condensed water discharged from the condensed water generation unit to perform a purification process;
A water level sensor for detecting a full water state in the water purifier;
Inside the front surface of the housing is provided with a temperature sensor that detects the temperature of the front surface,
The water pump is disposed below the fuel cell module, operates for a certain time after the water level sensor detects a full water condition, and operates when the temperature sensor reaches an upper limit value of a set temperature range. By stopping at the start and lowering to the lower limit value of the set temperature range, the water received from the water purifier is intermittently sent to the water tank .

According to this characteristic configuration, the water tank that stores the condensed water generated by condensing the water vapor contained in the exhaust gas from the fuel cell module is disposed above the fuel cell module that is relatively high temperature. Heat transfer from the battery module to the ceiling surface of the housing is blocked by a water tank, and excessive temperature rise on the ceiling surface, which is relatively frequently touched by users or the like in the housing, can be suppressed.
Furthermore, the condensed water discharged downward from the condensed water generation unit is pumped up to the water tank arranged above the fuel cell module through the water supply line by the water pump. At least a part of the cooling target portion around the peripheral side surface (the front surface, the rear surface, and the side surface) of the casing in a form such as circulating along the inner surface side of the cooling target portion of the casing constituting the water supply pipe. By functioning as a water-cooling unit that cools water by heat exchange with water supply, excessive temperature rise on the peripheral side surface of the housing can be suppressed.
In addition, since the water tank is disposed above the fuel cell module, for example, a tank drain section that drains the water tank in a form that overflows water above a certain level in the water tank is disposed near the ceiling of the housing. Will be. Therefore, the height of the tank drainage section located near the ceiling of the housing is higher than the drainage opening provided at the installation location of the fuel cell system, and as a result, a relatively large water head pressure is secured and good. Drainage can be performed.
Therefore, according to the present invention, in the fuel cell system, it is possible to suppress excessive temperature rise on the ceiling surface and the peripheral side surface in the casing while improving the drainage from the tank drainage section that drains the water tank that stores the condensed water. It is possible to provide technology that can
In addition, according to this characteristic configuration, the reformer and the steam generator are housed inside the fuel cell module disposed below the water tank, so that the water stored in the water tank is steam generated. There is no need to provide a pump or the like in the water supply conduit that leads to the vessel, and the water stored in the water tank can be supplied to the steam generator by its own weight.
In addition, according to this characteristic configuration, the water purifier that purifies the condensed water is disposed below the fuel cell module, so that the condensed water discharged downward from the condensed water generator is received by the water purifier. Can be temporarily stored. Therefore, since the water purifier functions as a so-called buffer tank, the operation state of the water pump can be set relatively freely.
Therefore, the operation state of the water pump is not always operated, but is intermittently operated, for example, when the water purifier is full or when the temperature of the cooling target portion is increased. If the water received from the water pump is intermittently sent to the water tank, the consumption of primary energy for the operation of the water pump can be reduced and the durability of the water pump can be improved.

Further features of the fuel cell system according to the present invention are as follows:
The fuel cell portion is in a solid oxide form.

  According to this characteristic configuration, even when the fuel cell unit accommodated in the fuel cell module is configured in a solid oxide form having a very high reaction temperature of about 700 ° C. to 1000 ° C., the fuel cell module Excessive temperature rise on the ceiling surface and the peripheral side surface of the housing can be effectively suppressed by the water tank disposed above and the water cooling on the peripheral side surface of the housing by the water cooling unit.

Further features of the fuel cell system according to the present invention are as follows:
The water-cooling part is located on the front surface of the fuel cell module in the housing.

In a normal fuel cell system, in order to reduce the depth dimension, the gap between the front surface of the housing and the fuel cell module kept at a high temperature is relatively narrow, and heat transfer from the fuel cell module causes the front surface of the housing to be relatively It tends to be hot. Moreover, since the front surface of a housing | casing is a part with which a user etc. touch relatively frequently compared with another surface, it is desirable to suppress excessive temperature rising.
Therefore, according to this characteristic configuration, the water cooling unit is disposed on the front surface of the fuel cell module, and the front surface of the housing that is likely to be relatively high temperature is cooled by the cooling unit as the cooling target portion. An excessive temperature rise can be suppressed, and inconveniences in handling of the user can be avoided well.

Further features of the fuel cell system according to the present invention are as follows:
It is in the point provided with the return water pipe which recirculates the water stored in the water tank to the primary side of the water pump.

  According to this characteristic configuration, by providing a return water pipe for returning the water stored in the water tank to the primary side (suction side) of the water pump, water is supplied from the water pump to the water tank via the water supply pipe. A circulation path composed of a supply path and a path for supplying water from the water tank to the water pump via the return water pipe is formed. Therefore, even when the amount of condensed water generated in the condensed water generation unit is small, the amount of water circulation in the circulation path is set to be large, and the cooling capacity to the peripheral side surface of the housing by the water cooling unit in which the water supply pipeline functions is set. It can be maintained in a high state, and as a result, excessive temperature rise on the peripheral side surface of the housing can be suitably suppressed.

Further features of the fuel cell system according to the present invention are as follows:
The condensed water generation unit is an exhaust heat recovery heat exchanger that generates hot water by heating the feed water by heat exchange with the exhaust gas.

  According to this feature configuration, if the condensate generation unit is configured as an exhaust heat recovery heat exchanger, the exhaust heat latent heat of the exhaust gas is also recovered by the exhaust heat recovery heat exchanger, and hot water heated appropriately is used for hot water supply. can do.

Elevation view showing a schematic configuration of the fuel cell system of the present embodiment The perspective view which shows schematic structure of the fuel cell system of this embodiment.

An embodiment of a fuel cell system according to the present invention will be described with reference to the drawings.
As shown in FIG. 1, the fuel cell system 1 according to the present embodiment includes a fuel cell module 3, a condensed water generation unit 4, and a water tank 8 arranged in a housing 2.
The casing 2 is formed as a rectangular parallelepiped box-shaped body made of a metal plate. Referring also to FIG. 2, the front surface 2f (front side in FIG. 1), both side surfaces 2s (left and right sides in FIG. 1), and back surface 2b. (Back side in FIG. 1), ceiling surface 2t (upper side in FIG. 1), bottom surface 2g (lower side in FIG. 1), and fuel gas F, air A, feed water S, exhaust gas between the outside E, and other interfaces for transmitting and receiving fluids, electricity, control signals and the like are provided.

The fuel cell module 3 is composed of a rectangular housing that houses therein a fuel cell portion 32 that generates electricity by reacting the fuel gas F taken from the outside with the air A supplied by the fan 10. The exhaust gas E from the battery unit 32 is discharged to the condensed water generation unit 4 disposed below the fuel cell module 3.
The fuel cell unit 32 is configured as a solid oxide fuel cell (SOFC). Specifically, the fuel cell unit 32 is configured as an SOFC stack in which a plurality of cells 33 are stacked. In each cell 33, the fuel gas F reformed by the reformer 35 and the air A are electrochemically reacted in a high temperature environment of about 700 ° C. to 1000 ° C. to generate power, and the generated electricity is not shown. It is sent to the inverter for use. Unreacted fuel gas (including intermediates generated in the electrochemical reaction) completely burns in the combustion space 34 at the upper outlet of the fuel cell unit 32.
The outer surface of the fuel cell module 3 is kept at a high temperature because the internal fuel cell unit 32 operates at a very high temperature, and the radiant heat is radiated toward the housing 2.

Inside the fuel cell module 3, above the combustion space 34, a reformer 35 that reforms the fuel gas F with steam and supplies it to the fuel cell unit 32, and heats the feed water S and supplies it to the reformer 35. A water vapor generator 36 for generating the generated water vapor is disposed.
The reformer 35 and the steam generator 36 are heated by the combustion in the combustion space 34, and the exhaust gas E generated by the combustion flows through the inside of the fuel cell module 3 to generate condensed water. Supplied to the unit 4.

The condensed water production | generation part 4 takes in the waste gas E discharged | emitted from the bottom face of the fuel cell module 3, and condenses the water vapor | steam contained in the said waste gas, and produces | generates condensed water W '.
Specifically, the condensed water generation unit 4 is configured as an exhaust heat recovery heat exchanger that generates hot water H by heating the feed water S by heat exchange with exhaust gas. That is, the exhaust heat recovery heat exchanger constituting the condensed water generation unit 4 is connected to the exhaust gas receiving space 41 for receiving the exhaust gas E discharged downward from the bottom surface of the fuel cell module 3 and the side surface of the exhaust gas receiving space 41. And an exhaust passage 42 for discharging the exhaust gas E taken in from the exhaust gas receiving space 41 to the outside, and in the exhaust gas receiving space 41, a heat transfer tube 43 through which the feed water S flows is arranged. In the exhaust gas receiving space 41, heat exchange between the high temperature exhaust gas E and the low temperature feed water S is performed. Therefore, the feed water S flowing inside the heat transfer pipe 43 is discharged as hot water H by being heated by heat exchange with the high-temperature exhaust gas E, for example, a hot water storage tank (not shown) provided with the hot water H outside. ) Is once stored and then supplied to a hot water supply unit or the like for use. On the other hand, the exhaust gas E flowing through the exhaust gas receiving space 41 is cooled by heat exchange with the cold water supply S, whereby water vapor contained in the exhaust gas E is condensed to generate condensed water. 'Is dropped into the condensed water receiving portion 44 at the bottom of the exhaust gas receiving space 41 and discharged to the outside.
Furthermore, below the condensed water production | generation part 4, the refinement | purification process is performed in the form which condensate water W 'discharged | emitted from the condensed water production | generation part 4 is temporarily stored and passed through purification materials, such as ion exchange resin. A water purifier 5 for discharging the water W after the purification treatment is disposed.

The water tank 8 is configured as an open tank that stores the condensed water W ′ discharged from the condensed water generation unit 4.
Specifically, the water tank 8 is disposed above the fuel cell module 3 and receives and stores the water W discharged from the water purifier 5.
An overflow drain pipe 83 is connected to the upper side surface of the water tank 8 as a tank drainage section for draining the stored water W. Yes.
Since the overflow drain pipe 83 is disposed near the ceiling of the casing 2, the overflow drain pipe 83 is disposed in the casing 2 with respect to a drain outlet (not shown) provided at the installation location of the fuel cell system 1. The height of the overflow drain pipe 83 arranged in the vicinity of the ceiling is increased, and as a result, a relatively large water head pressure can be secured and good drainage can be performed.
Further, a pipe 81 for replenishing the water tank 8 with water supply S and a water supply valve 82 disposed in the pipe 81 and automatically opened as the water level of the water tank 8 decreases are provided. That is, when the water level of the water tank 8 is lowered, the water supply valve 82 is opened and the water supply W is replenished via the pipe line 81, whereby the water level of the water tank 8 is maintained at a predetermined water level.

The water pump 6 sends the condensed water W ′ discharged from the condensed water generation unit to the water tank 8. Specifically, the water pump 6 is disposed below the fuel cell module 3 and is discharged from the water purifier 5. W is sent to the water tank 8 disposed above through the water supply line 7.
Further, on the lower side surface of the water tank 8, the water vapor generator 36 in which the water W stored in the water tank 8 is accommodated inside the fuel cell module 3 disposed on the lower side of the water tank 8. A water supply pipe 85 is connected to the pipe. Since the water W stored in the water tank 8 can be supplied to the water vapor generator 36 by its own weight through the water supply pipe 85, the water supply pipe 85 does not require a pump for water supply.

  Further, a return water pipe 9 is connected to the lower side surface of the water tank 8 in addition to the water supply pipe 85, and this return water pipe 9 is accompanied by a valve opening operation of the on-off valve 91. Is recirculated to the primary side of the water pump 6, specifically to the inlet side of the water purifier 5. Since the water W stored in the water tank 8 is returned to the inlet side of the water purifier 5 in this manner, the water purifier 5 disposed below the fuel cell module 3 temporarily stores the water W. It functions as a so-called buffer tank. Therefore, regardless of the amount of condensed water W ′ generated in the condensed water generation unit 4, the water supply amount and operating state of the water pump 6 are set relatively freely, and the flow rate and flow state of the water W in the water supply line 7 are set. It can be set relatively freely.

In the fuel cell system 1 as described above, since the fuel cell module 3 is maintained at a relatively high temperature, there is a concern that the casing 2 may be excessively heated. In particular, the front surface 2f that is a part of the peripheral side surface of the housing 2 and the ceiling surface 2t of the housing 2 are relatively frequently touched by users and the like. It is desirable.
Therefore, the fuel cell system 1 of the present embodiment has a feature for suppressing the excessive temperature rise of the casing 2 with respect to the arrangement location of the water tank 8 and the water supply pipe line 7 that supplies the water W to the water tank 8. The features will be described below.

  The water tank 8 is disposed above the fuel cell module 3 as described above. Accordingly, heat transfer from the ceiling surface of the fuel cell module 3 to the ceiling surface 2t of the housing 2 is blocked by the water tank 8, and as a result, the ceiling surface 2t that is frequently touched by the user or the like in the housing 2 is excessive. The temperature rise is suppressed.

Inside the housing 2, a water supply conduit 7 that guides water W from a water pump 6 disposed near the bottom to a water tank 8 disposed near the ceiling includes at least a part of the front surface 2 f on the peripheral side surface of the housing. The cooling target part functions as a water cooling part X that cools the cooling target part by heat exchange with the water supply W.
That is, the water supply pipe 7 is constituted by a heat transfer pipe arranged in a form that goes upward while meandering in the horizontal direction along the inner surface side of the front surface 2 f of the housing 2. Then, when the water W flows through the heat transfer pipes constituting the water supply pipe 7, the front surface 2f of the casing 2 receiving the radiant heat of the fuel cell module 3 is cooled by heat exchange with the water W, and as a result, the casing Excessive temperature rise on the front surface 2f, which is relatively high in frequency with which a user or the like touches the body 2, is suppressed.

Furthermore, the water pump 6 does not always operate, but intermittently supplies water received from the water purifier 5 in such a manner that it operates only when the water purifier 5 is full or when the temperature of the front surface 2f of the housing 2 rises. Delivered to water tank 8.
Specifically, the water purifier 5 is provided with a water level sensor 51 that detects a full water state. The water level sensor 51 detects that the water purifier 5 is full and stores it in the water purifier 5. The water pump 6 is operated for a certain time immediately before the water being overflowed, and the water W stored in the water purifier 5 is sent to the water tank 8.

Further, a temperature sensor 11 that detects the temperature of the front surface 2f is provided inside the front surface 2f of the housing 2, and the temperature of the front surface 2f of the housing 2 detected by the temperature sensor 11 is within a set temperature range. When the upper limit value is reached, the water pump 6 is activated and water cooling of the front surface 2f is started, and when the temperature of the front surface 2f detected by the temperature sensor 11 falls to the lower limit value of the set temperature range, the water pump 6 is turned on. It stops and the water cooling of the said front surface 2f is stopped.
At this time, when the water W stored in the water purifier 5 is insufficient, the open / close valve 91 is opened to remove the water W stored in the water tank 8 through the return water pipe 9. 5, a relatively large amount of water W can be passed through the water supply pipe 7 that functions as the water cooling section X. As a result, the water cooling section X has a relatively high cooling with respect to the front surface 2 f of the housing 2. Can demonstrate ability.
The temperature sensor 11 may be arranged not to detect the temperature of the casing 2 itself but to detect the temperature of the outer surface of the fuel cell module 3 that emits radiant heat to the casing 2. I do not care.
Further, instead of intermittently operating the water pump 6, for example, the water pump 6 may be operated continuously according to the amount of condensed water W ′ generated.

[Other Embodiments]
Finally, other embodiments of the present invention will be described. Note that the configuration of each embodiment described below is not limited to being applied independently, and can be applied in combination with the configuration of other embodiments as long as no contradiction arises.

(1) In the above embodiment, of the peripheral side surfaces 2f, 2s, and 2b of the housing 2, the cooling target portion that is subject to water cooling by the water cooling portion X is the front surface 2f, but the other side surfaces 2s and the back surface 2b are You may water-cool with the water-cooling part X as a cooling object part.

(2) In the above embodiment, the tank drainage unit for draining the water tank 8 is configured by the overflow drainage pipe 83 connected to the upper side surface of the water tank 8, but a tank drainage unit having another configuration may be provided. For example, a drain pipe may be connected to the lower side surface of the water tank 8, and drainage may be performed by opening and closing a drain valve provided in the drain pipe.

(3) In the above embodiment, the fuel cell unit 32 is configured as a solid oxide fuel cell, but may be configured as another type of fuel cell.

(4) In the above embodiment, the return water pipe 9 and the water purifier 5 are provided, but these may be omitted as appropriate.

  The present invention includes a fuel cell module that houses therein a fuel cell unit that generates power by reacting fuel gas and air and discharges exhaust gas from the fuel cell unit, and the exhaust gas discharged from the fuel cell module. A condensed water generating unit that condenses the generated water vapor to generate condensed water and discharges the condensed water downward, and a tank that stores the condensed water discharged from the condensed water generating unit and drains the stored water A water tank having a drainage part can be suitably used as a fuel cell system that is arranged in a housing.

1: Fuel cell system 2: Housing 2f: Front (circumferential side)
3: Fuel cell module 4: Condensate water generation unit 5: Water purifier 6: Water pump 7: Water supply line 8: Water tank 9: Return water line 32: Fuel cell unit 35: Reformer 36: Water vapor generator 83 : Overflow drain (tank drain)
85: Water supply line 32: Fuel cell part A: Air E: Exhaust gas F: Fuel gas H: Hot water S: Water supply W, W ': Water (condensed water)
X: Water cooling part

Claims (5)

A fuel cell module that houses therein a fuel cell unit that generates electricity by reacting fuel gas and air, and discharges exhaust gas from the fuel cell unit;
A condensed water generating unit for condensing water vapor contained in the exhaust gas discharged from the fuel cell module to generate condensed water and discharging the condensed water downward;
A fuel cell system in which a water tank having a tank drainage section for storing the condensed water discharged from the condensed water generation section and draining the stored water is disposed in a housing,
The water tank is disposed above the fuel cell module;
A water pump for sending the condensed water discharged from the condensed water generation unit to the water tank;
The water supply pipe line to the water tank by the water pump is configured as a water cooling part that cools at least a part to be cooled on the peripheral side surface of the housing by heat exchange with water supply,
A reformer for steam reforming the fuel gas and supplying it to the fuel cell unit, and a steam generator for heating the feed water and generating steam to be supplied to the reformer are provided inside the fuel cell module. Contained,
A water supply conduit for guiding water stored in the water tank to the steam generator by its own weight ;
A water purifier that is disposed below the fuel cell module and temporarily stores the condensed water discharged from the condensed water generation unit to perform a purification process;
A water level sensor for detecting a full water state in the water purifier;
Inside the front surface of the housing is provided with a temperature sensor that detects the temperature of the front surface,
The water pump is disposed below the fuel cell module, operates for a certain time after the water level sensor detects a full water condition, and operates when the temperature sensor reaches an upper limit value of a set temperature range. A fuel cell system that intermittently sends water received from the water purifier to the water tank by stopping when the water temperature starts and decreases to a lower limit value of the set temperature range .   The fuel cell system according to claim 1, wherein the fuel cell unit is in a solid oxide form.   The fuel cell system according to claim 1, wherein the water cooling unit is disposed on a front surface of the fuel cell module in the housing.   The fuel cell system according to any one of claims 1 to 3, further comprising a return water pipe for returning water stored in the water tank to a primary side of the water pump. The fuel cell system according to any one of claims 1 to 4, wherein the condensed water generation unit is an exhaust heat recovery heat exchanger that generates hot water by heating the feed water by heat exchange with the exhaust gas .

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