JPH10223249A - Fuel cell system and flow path freezing prevention method for fuel cell system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the plugging of a flow path caused by the freeze of condensed water by the drop of outside temperature, in the flow path of an exhaust gas from a fuel cell. SOLUTION: A fuel cell system 10 has a methanol adding path 66. The methanol adding path 66 is a flow path connecting a methanol tank 13 for storing methanol, which is a raw material for producing a fuel gas supplying to a fuel cell 20 and an oxidizing exhaust gas path 61, into which an oxidizing exhaust gas from the fuel cell 20 is introduced. By supplying methanol to the oxidizing exhaust gas path 61 through the methanol adding path 66, methanol is mixed to produced water which is condensed in the oxidizing exhaust gas path 61. Since the condensed water mixed with methanol drops in its melting point, even if the outside temperature drops during the operation of the fuel cell system 10, the condensed water does not freeze.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel cell device and a method for preventing freezing of a flow channel of a fuel cell device.
The present invention relates to a fuel cell device which receives an supply of a fuel gas and an oxidizing gas to advance an electrochemical reaction, obtains an electromotive force by this electrochemical reaction and generates water, and a method for preventing a freezing of a flow path of such a fuel cell device.

[0002]

2. Description of the Related Art When generated water is generated by an electrochemical reaction that proceeds in a fuel cell device, water vapor passes through a flow path of gas discharged from the fuel cell, or condensed water is generated in the flow path. Or Hereinafter, an electrochemical reaction that proceeds in a solid polymer electrolyte fuel cell will be described as an example of an electrochemical reaction that generates product water.

H ₂ → 2H ⁺ + 2e ⁻ (1) (1/2) O ₂ + 2H ⁺ + 2e ⁻ → H ₂ O (2) H ₂ + (1/2) O ₂ → H ₂ O (3) )

Equation (1) shows the reaction on the anode side,
Equation (2) represents the reaction on the cathode side, and the reaction shown in equation (3) proceeds in the entire fuel cell. in this way,
Since water is generated on the cathode side with the progress of the electrochemical reaction, the oxidized exhaust gas discharged from the fuel cell contains water vapor composed of such generated water. In the case where compressed air is supplied to the cathode side in a solid polymer electrolyte fuel cell, water vapor may be previously applied to the compressed air in order to prevent the electrolyte membrane from drying. With such a configuration, in addition to the water generated by the electrochemical reaction, the oxidized exhaust gas discharged from the fuel cell includes:
Water vapor previously applied to the compressed air will also be included. In the following description, water (steam) contained in exhaust gas discharged from the fuel cell will be referred to as generated water without distinguishing these steams.

[0005] When the operation of the fuel cell is stopped, the generated water condenses in the exhaust gas channel as the temperature of the channel decreases and the saturated vapor pressure in the channel decreases. As described above, when the fuel cell is left in a state where the condensed product water remains in the exhaust gas flow path, when the outside temperature falls below the freezing point and the flow path is cooled, water droplets remaining in the gas flow path are frozen. Start. When the generated water freezes in the gas flow path, the gas flow path is narrowed, and the gas flow path may be blocked by the frozen generated water. If the gas flow path is narrowed or blocked by the frozen product water as described above, the gas flow will be hindered the next time the fuel cell is operated. Therefore, conventionally, when condensed water is frozen in the flow path in the fuel cell due to a decrease in outside air temperature, the frozen gas flow path is actively heated when the operation of the fuel cell is restarted. It was necessary to melt the frozen product water and secure a gas flow path.

Further, as a configuration for preventing water remaining in a predetermined flow path of the fuel cell device from freezing, a configuration in which residual water is removed from the flow path may be considered.
For example, normally, a fuel cell device is provided with a mechanism for circulating cooling water around the fuel cell to keep the operating temperature of the fuel cell within a certain range, but this cooling water freezes after the operation of the fuel cell ends. In order to prevent such a situation, a configuration has been proposed in which the cooling water is withdrawn from the cooling water passage when the operation is stopped (for example, Japanese Patent Application Laid-Open No. 6-223855).
In such a fuel cell device, when the operation of the fuel cell is stopped, a gas (oxidizing gas) is pumped into the cooling water passage to extract the cooling water from the cooling water passage, and the extracted cooling water is stored in a predetermined cooling water storage device. It has a configuration. Therefore, even when the outside air temperature decreases after the operation of the fuel cell is stopped, the cooling water does not freeze in the cooling water passage.

[0007]

However, in the case where the above-described configuration for pumping gas into the flow path to extract water from the flow path and storing the extracted water is applied to the oxidizing exhaust gas flow path, the above-described structure is adopted. However, there is a problem that it is difficult to sufficiently remove the generated water in the oxidizing exhaust gas flow path even if the gas is used.
That is, since the fuel cell device needs to be accommodated in a predetermined space, the flow path of the oxidizing exhaust gas is formed in a shape having a predetermined bent portion. The generated water is not easily blown off even by the pumped gas. As described above, even when the generated water remains partially, the flow path is narrowed at the time of freezing, and the flow path may be blocked. Furthermore, when storing the extracted water, it was considered that even if the storage device had excellent heat insulation properties, the water would freeze inside the storage device when the outside temperature dropped significantly.

Alternatively, when the frozen product water is melted by heating the gas flow path when the operation of the fuel cell is restarted, energy is required for melting the product water, so that the energy efficiency of the entire system is reduced. Would. In addition, the provision of a configuration for heating the flow channel increases the size of the device. Furthermore, since the operation of heating the gas flow path is performed when the operation is restarted, a long time is required when the fuel cell is started. As described above, in the exhaust gas channel discharged from the fuel cell, as a countermeasure against condensed generated water freezing and narrowing or closing the channel, after the generated water has blocked the channel. Only those that have been implemented and are accompanied by a decrease in energy efficiency have been known.

The fuel cell device and the method for preventing freezing of the flow channel of the fuel cell device according to the present invention solve such a problem, and when the outside air temperature decreases in the flow channel of the exhaust gas discharged from the fuel cell, the flow channel is prevented. The purpose of the invention is to prevent the condensed water from freezing and blocking the flow path, and has the following configuration.

[0010]

The fuel cell device according to the present invention receives fuel supply on the anode side,
A fuel cell device that receives an oxidizing gas containing oxygen on the cathode side and obtains an electromotive force by an electrochemical reaction,
In the gas flow path connected to the electrode side on which the generated water is generated by the electrochemical reaction, while the operation of the fuel cell device is stopped, the gas flow path is prevented from being blocked due to the freezing of the generated water present in the gas flow path. The gist of the present invention is to provide a blockage preventing means.

In the fuel cell device of the present invention having the above-described structure, the fuel is supplied to the anode side, the oxidizing gas containing oxygen is supplied to the cathode side, and the electromotive force is generated by an electrochemical reaction. Get. In the gas flow path connected to the electrode side on which the generated water is generated by the electrochemical reaction, while the operation of the fuel cell device is stopped, the gas flow path due to the freezing of the generated water present in the gas flow path is blocked. Prevented by prevention means.

[0012] According to such a fuel cell device, even if the outside air temperature decreases during the stoppage of the operation of the fuel cell device, the generated water freezes in the flow path connected to the electrode side where the generated water is generated. Will not be blocked. Therefore, the next time the fuel cell device is started, no time is required to secure the gas flow path, and the guidance time can be reduced. further,
Since it is not necessary to heat the gas flow path to melt the frozen product water in order to secure the gas flow path, energy for heating the flow path becomes unnecessary, and the energy efficiency of the entire apparatus does not decrease.

In the fuel cell device according to the present invention, the blocking prevention means may be a freezing prevention means for preventing freezing of the generated water in a gas flow path connected to an electrode side on which the generated water is generated.

In such a fuel cell device, by preventing freezing of the generated water in the gas flow path connected to the electrode side on which the generated water is generated, the gas flow path is prevented from being blocked. . As described above, since the generated water does not freeze in the flow path, a gas flow path can always be secured in the flow path.

[0015] In such a fuel cell device, the fuel supplied to the anode side is a fuel generated from alcohol-based hydrocarbon as a raw fuel, and the anti-freezing means is connected to an electrode side where the generated water is generated. The gas flow path
A configuration including a raw fuel mixing means for supplying the raw fuel is also preferable.

The fuel cell device configured as described above
A fuel produced by using alcohol-based hydrocarbon as a raw fuel is supplied to the anode side to obtain an electromotive force by an electrochemical reaction. The raw fuel is supplied to a gas flow path connected to an electrode side on which water produced by the electrochemical reaction is generated.

According to such a fuel cell device, since the alcohol-based hydrocarbon is easily mixed with water, the produced water contains the alcohol-based hydrocarbon in the gas flow path. The melting point of alcoholic hydrocarbons is lower than that of water, and thus the generated water in the gas flow path has a lower melting point, and does not freeze even when the outside air temperature decreases when the operation of the fuel cell device is stopped. . Further, since raw fuel is used as an antifreezing agent for generated water, there is no need to specially prepare an antifreezing agent to be added to the generated water, and the configuration can be simplified.

In the fuel cell device having the above configuration,
At least a part of the raw fuel composed of the alcohol-based hydrocarbon, and a water / raw fuel storage unit for preparing the fuel by maintaining a mixed state of water required to generate the fuel from the raw fuel, It is also preferable that the apparatus further comprises a product water collecting means for condensing the product water in a gas flow path connected to an electrode side on which the product water is generated, and collecting the condensed product water in the water / raw fuel storage unit. is there.

In the fuel cell device having such a configuration, at least a part of the raw fuel composed of the alcohol-based hydrocarbon is mixed with the water required to produce the fuel from the raw fuel. It is held in the storage unit and is prepared for the generation of the fuel. Further, in a gas flow path connected to the electrode side where the generated water is generated, the generated water is mixed with the raw fuel, and the generated water containing the raw fuel is condensed and collected in the water / raw fuel storage unit. You.

As described above, since the raw fuel used for preventing the generated water from freezing is recovered in the water / raw fuel storage section, the raw fuel used for preventing the generated water from freezing is discharged. It is used for the production of the fuel without the above, and the raw fuel is not wastefully consumed to prevent freezing of the produced water. Further, since the water required for the generation of the fuel is mixed and stored with at least a part of the raw fuel to lower the melting point, the water required for the generation of the fuel is also generated when the operation of the fuel cell device is stopped. It does not freeze even when the outside temperature drops.

Here, the alcohol-based hydrocarbon may be methanol. With such a configuration, inexpensive methanol can be used as a raw fuel for generating fuel to be supplied to the fuel cell. As a method for generating fuel to be supplied to a fuel cell from a raw fuel, a method of reforming methanol to generate a hydrogen-rich fuel gas is widely known, and by using methanol as a raw fuel, the present invention can be easily performed. Can be implemented.

Further, in the fuel cell device according to the present invention, the freeze prevention means may be a water removing means for removing the generated water from a gas flow path connected to an electrode side where the generated water is generated.

In such a fuel cell device, the generated water is frozen in the gas flow path by removing the generated water in the gas flow path connected to the electrode side where the generated water is generated. To prevent As described above, since the generated water is removed from the inside of the flow path, a gas flow path can always be secured in the flow path.

Here, the water removing means is formed in a gas flow path connected to the electrode side where the generated water is generated, is capable of storing water, and has a drainage mechanism having a drainage mechanism for discharging the stored water. May be adopted.

In such a fuel cell, the water generated by the electrochemical reaction is stored and drained in a water storage portion provided in a gas flow path connected to an electrode side on which the generated water is generated. Therefore, the generated water can be removed from the gas flow path.

Further, the water removing means passes a high-temperature gas discharged from a predetermined high-temperature portion provided in the apparatus including the fuel cell in a gas flow path connected to the electrode side on which the generated water is generated. It may be configured as a gas introduction means.

In such a fuel cell device, a high-temperature gas discharged from a predetermined high-temperature portion provided in the device including the fuel cell device passes through a gas flow path connected to the electrode side on which the generated water is generated. Therefore, the generated water in the gas flow path is vaporized by the amount of heat of the introduced high-temperature gas, and is discharged from the gas flow path together with the introduced high-temperature gas. Therefore, the generated water can be removed from the gas flow path. Here, since the high-temperature gas that passes through the gas flow path is a high-temperature gas discharged from a predetermined high-temperature portion provided in the device including the fuel cell device, a special device is required to obtain the high-temperature gas. There is no need to provide.

[0028] Such a fuel cell device is provided with a reformer for reforming a raw fuel made of hydrocarbon to produce the fuel, and the high-temperature high-temperature gas passing through the gas flow path by the gas introducing means. It is also preferable that the gas is an exhaust gas discharged from a heating device provided to raise the temperature of the inside of the reformer to a temperature range suitable for the reforming reaction.

In such a fuel cell device, a heating device is used to raise the temperature of the inside of a reformer for reforming a raw fuel made of hydrocarbon to produce the fuel to a temperature range suitable for a reforming reaction. And the exhaust gas discharged from the heating device is passed through the gas flow path as the high-temperature gas. The temperature suitable for the hydrocarbon reforming reaction is generally very high, and by using the exhaust gas discharged from the heating device, the inside of the gas passage can be sufficiently dried.

Further, in the fuel cell device of the present invention, the blocking prevention means includes a retention prevention means for preventing the generated water from condensing and remaining in a gas flow path connected to the electrode side on which the generated water is generated. It is good also as being.

In such a fuel cell device, the gas flow path is closed by preventing the generated water from remaining in the gas flow path connected to the electrode side on which the generated water is generated. To prevent As described above, since the generated water does not stay in the flow path, even when the generated water is frozen in the flow path, the flow path of the gas can be always secured.

Here, the stagnation preventing means is provided in a gas flow path connected to the electrode side on which the generated water is generated, and is a water capturing means capable of capturing water while securing a space through which the gas passes. can do. With such a configuration, even when the generated water is frozen in the gas flow path, it is possible to continue to secure a space through which the gas passes.

Here, the water trapping means may have a mesh structure provided on the inner wall surface of a gas flow path connected to the electrode side where the generated water is generated. In such a fuel cell device, the generated water condensed in the gas flow path is captured in a mesh structure provided on the inner surface of the gas flow path, and is spread and held in the mesh structure by capillary action. Therefore, even when the outside air temperature decreases during the shutdown of the fuel cell device, the generated water only freezes in the mesh structure, and the space through which the gas passes is secured,
The generated water does not stay and block the gas flow path.

Further, in the fuel cell device of the present invention, the electrode side on which the generated water is generated may be the cathode side.

In the first method for preventing freezing of the flow channel of the fuel cell device according to the present invention, a fuel produced by using an alcohol-based hydrocarbon as a raw fuel and an oxidizing gas containing oxygen are supplied to generate a fuel by an electrochemical reaction. A method for preventing freezing of a flow path of a fuel cell device for obtaining electric power, wherein the raw fuel is supplied to a gas flow path connected to an electrode side on which water generated by the electrochemical reaction is connected.

According to the method for preventing freezing of the flow path of the fuel cell device, in the gas flow path connected to the electrode side where the generated water is generated, the generated water is mixed with the alcohol-based hydrocarbon as the raw fuel. The melting point is reduced. Therefore, even when the outside air temperature decreases during the stoppage of the operation of the fuel cell device, the generated water does not freeze in the gas flow path to block the gas flow path, thereby causing no inconvenience.

In the second method for preventing freezing of a flow channel of a fuel cell device according to the present invention, the anode is supplied with fuel and the cathode is supplied with oxygen-containing oxidizing gas. A method of preventing freezing of a flow path of a fuel cell device that obtains an electromotive force by a reaction, comprising storing condensed water generated in a gas flow path connected to an electrode side on which water generated by the electrochemical reaction is generated, The gist of the present invention is to discharge the stored condensed water when the operation is stopped.

According to such a method for preventing freezing of the flow path of the fuel cell device, the generated water is discharged after being condensed and stored in the gas flow path connected to the electrode side where the generated water is generated. Therefore, the generated water is removed from the inside of the flow passage, and even when the outside air temperature is reduced while the operation of the fuel cell device is stopped, the generated water freezes in the gas flow passage and blocks the gas flow passage. This does not cause any inconvenience.

Further, in the third method for preventing freezing of the flow channel of the fuel cell device according to the present invention, the fuel is supplied to the anode side and the oxidizing gas containing oxygen is supplied to the cathode side. A method for preventing freezing of a flow channel of a fuel cell device that obtains an electromotive force by a reaction, comprising: The high-temperature gas discharged from the high-temperature portion is passed through.

According to such a flow cell freezing prevention method for a fuel cell device, a predetermined high temperature portion provided in the device including the fuel cell is provided in a gas flow channel connected to an electrode side on which the generated water is generated. In order to allow the discharged high-temperature gas to pass, the generated water in the gas flow path is vaporized by the high-temperature gas and discharged together with the high-temperature gas to the outside of the fuel cell device. Therefore, the generated water is removed from the inside of the flow passage, and even when the outside air temperature is reduced while the operation of the fuel cell device is stopped, the generated water freezes in the gas flow passage and blocks the gas flow passage. This does not cause any inconvenience.

[0041]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In order to further clarify the structure and operation of the present invention described above, embodiments of the present invention will be described below based on examples. FIG. 1 is an explanatory diagram illustrating an outline of the configuration of the fuel cell device 10 according to the first embodiment. When the operation of the fuel cell is stopped, the fuel cell device 10 of the present embodiment supplies the raw fuel methanol to the flow path of the oxidized exhaust gas containing the generated water, and mixes the methanol with the generated water in the flow path. By doing so, the coagulation temperature of the produced water is reduced. With such a configuration, when the outside air temperature decreases while the operation of the fuel cell is stopped,
The generated water remaining in the flow path is prevented from freezing. First, the overall configuration of the fuel cell device 10 will be described with reference to FIG.

The fuel cell device 10 includes the raw fuel storage device 1
2, a reformer 16, a fuel cell 20, and a controller 30 are provided as main components. Methanol, which is a raw fuel stored in the raw fuel storage device 12, is reformed by the reformer 16 to become a hydrogen-rich reformed gas, and is supplied to an electrochemical reaction in the fuel cell 20. Hereinafter, the fuel cell device 1
Each component constituting 0 will be described.

The raw fuel storage device 12 includes a methanol tank 13 and a water / methanol tank 14. The methanol tank 13 is a tank that stores methanol that is a raw fuel for a fuel cell. Water / methanol tank 1
Reference numeral 4 denotes a tank for storing a water-methanol mixture obtained by mixing water and methanol at a ratio of about 2: 1 (volume ratio).
The methanol tank 13 and the water / methanol tank 14 are connected by a flow path 40, and the flow path 40 is provided with a valve 41 which is an electromagnetic valve. When the valve 41 is opened, methanol is supplied from the methanol tank 13 to the water / methanol tank 14. The water / methanol tank 14 is provided with a specific gravity sensor 42 for detecting the specific gravity of the water / methanol mixed liquid stored in the water / methanol tank 14. The specific gravity sensor 42 and the valve 41 are connected to the control unit 30. The control unit 30 adjusts the open state of the valve 41 based on the information on the specific gravity input from the specific gravity sensor 42, and determines the ratio of water to methanol in the water / methanol mixture stored in the water / methanol tank 14. , And keep the above values.

A raw fuel supply path 50 is connected to the water / methanol tank 14. A water / methanol mixed liquid is supplied from the water / methanol tank 14 to the reformer 16 via the raw fuel supply path 50. You. Here, a pump 68 is provided in the raw fuel supply path 50.
The amount of the water-methanol mixture to be supplied to the reformer 16 can be adjusted by the driving state of. Pump 68
Are connected to the control unit 30, and the driving state is controlled by the control unit 30.

The reformer 16 is provided with a burner 15. The burner 15 is a device for supplying heat required for a reforming reaction in the reforming device 16. Burner 15
Is supplied from the methanol tank 13 through the methanol channel 43. Further, an air supply path 46 is connected to the burner 15, and air is supplied from the blower 45 via the air supply path 46. Further, the burner 15 is supplied with a fuel exhaust gas, which will be described later, discharged from the fuel cell 20 via a fuel exhaust gas passage 60. The burner 15 uses the methanol and the fuel exhaust gas as fuel to generate thermal energy by combustion and supplies the thermal energy to the reformer 16. First, the combustion gas generated by the burner 15 is supplied to a later-described evaporating unit 17 provided in the reformer 16 via a combustion gas supply path 54.

In the burner 15, when the fuel cell device 10 is started, a combustion reaction is performed using methanol supplied through the methanol flow path 43.
Reaction progresses in the fuel cell 2
When the fuel exhaust gas is supplied from 0, the fuel for the combustion reaction is switched from methanol to the fuel exhaust gas. Here, a valve 44 connected to the control unit 30 is provided in the methanol flow path 43, and the open state of the valve 44 is controlled by the control unit 30. Control unit 30
Switches the fuel for combustion from methanol to fuel exhaust gas by controlling the open state of the valve 44 in accordance with the state of the electrochemical reaction progressing in the fuel cell 20, and burns the fuel if the fuel exhaust gas is insufficient. Methanol is supplemented as fuel for combustion at 15. The blower 45 is also connected to the control unit 30, and supplies air required for a combustion reaction in the burner 15 to the burner 15 according to a drive signal from the control unit 30.

The reformer 16 includes an evaporator 17 and a reformer 18.
And a CO selective oxidation unit 19. Evaporation unit 17
Vaporizes and raises the temperature of the water-methanol mixture prior to the reforming reaction. The reforming section 18 reforms the water-methanol mixed gas vaporized and heated in the evaporating section 17 to generate a hydrogen-rich reformed gas. The CO selective oxidizing unit 19 reduces the concentration of carbon monoxide in the reformed gas to convert the reformed gas into a fuel gas having a low concentration of carbon monoxide. Through the raw fuel supply channel 50
The water-methanol mixture supplied from the methanol tank 14 is first introduced into the evaporating section 17. The evaporating section 17,
The reforming section 18 and the CO selective oxidizing section 19 are connected by gas flow paths 51 and 52, respectively. Hereinafter, each component of the reformer 16 will be described in detail.

As described above, the evaporator 17 is a device for evaporating and raising the temperature of the water-methanol mixture, and energy for this purpose is supplied from the burner 15. That is, the high-temperature combustion gas generated by the combustion reaction in the burner 15 is supplied to the evaporator 17 via the combustion gas supply passage 54. The combustion gas supply passage 54 forms a heat exchange section (not shown) inside the evaporating section 17. The heat exchange section heat-exchanges the combustion gas with the water / methanol mixture to vaporize the water / methanol mixture. Raise the temperature. The water-methanol mixed gas that has been vaporized and heated is introduced into the reforming section 18 through the gas flow path 51. The combustion gas that has undergone heat exchange in the evaporator 17 is discharged to the outside of the fuel cell device 10 through a combustion gas branch 58 branched from the combustion gas passage 55.

The combustion gas passage 55 from which the combustion gas exchanged in the evaporator 17 is discharged is connected to the reformer 18 in addition to branching to form the combustion gas branch 58. A heat exchange unit (not shown) is formed inside the reforming unit 18. Further, the combustion gas path 55 is also connected to the CO selective oxidizing section 19 as a combustion gas path 56, and similarly forms a heat exchange section (not shown) inside. CO selective oxidation unit 19
Is connected to a combustion gas passage 57, so that the combustion gas that has passed through the heat exchange section can be discharged to the outside of the fuel cell device 10.

Here, the combustion gas branch passage 58 and the combustion gas passage 55 are provided with valves 58A, 58A,
55A are provided. These valves 58
A and 55A are connected to the control unit 30.
Switches the flow path of the combustion gas discharged from the burner 15 by controlling the open / close state of these valves. By such opening and closing control of the valve, the combustion gas is also introduced into the reforming section 18 and the CO selective oxidizing section 19 when the fuel cell device 10 is started, and the temperature of the reforming section 18 and the CO selective oxidizing section 19 is raised. In this way, the time required for operation in a steady state is reduced. When the temperatures in the reforming section 18 and the CO selective oxidizing section 19 are sufficiently raised, the switching of the valve causes the combustion gas to be discharged from the evaporating section 17 and then discharged outside the fuel cell device 10. .

The reforming section 18 includes a reforming catalyst Cu—Zn
A catalyst is provided inside, and the water-methanol mixed gas is passed through the surface of the reforming catalyst to reform the water-methanol mixed gas to generate a hydrogen-rich reformed gas. The steam reforming reaction that proceeds in the reforming section 18 will be described below.

CH ₃ OH → CO + 2H ₂ -90.0 (kJ / mol) (4) CO + H ₂ O → CO ₂ + H ₂ +40.5 (kJ / mol) (5) CH ₃ OH + H ₂ O → CO ₂ + 3H ₂ -49.5 (kJ / mol) (6)

In the steam reforming reaction of methanol, the decomposition reaction of methanol represented by the formula (4) and the conversion reaction of carbon monoxide represented by the formula (5) proceed simultaneously, and as a whole (6) The reaction of the equation takes place. As described above, the reforming reaction is an endothermic reaction, and heat energy is required to advance the reaction. In the reformer 16 of the present embodiment, in the evaporator 17, the temperature of the water methanol gas is sufficiently increased by the combustion gas supplied from the burner 15, so that the water methanol gas brings a necessary amount of heat to the reformer 18. It has a configuration. Therefore, except when the fuel cell device 10 is started, the combustion gas supplied from the burner 15 is discharged without being introduced into the reforming section 18 as described above.

The CO selective oxidizing section 19 is a device for selectively oxidizing carbon monoxide in the reformed gas generated in the reforming section 18 to obtain a fuel gas having a sufficiently low carbon monoxide concentration. As described above, the reforming reaction that proceeds in the reforming section 18 is (4)
The reaction proceeds according to the formulas (6) and (6), and if these reactions are completely carried out, carbon monoxide will not be finally generated. However, in an actual fuel reformer, the above (5)
Since it is difficult to completely carry out the reaction of the formula, the fuel gas reformed by the fuel reformer contains a trace amount of carbon monoxide as a by-product. However, when the reformed gas containing carbon monoxide is supplied to the fuel cell as the fuel gas, the carbon monoxide is adsorbed on the platinum catalyst provided in the fuel cell and deteriorates the catalyst. Therefore, in the reforming apparatus 16, the CO selective oxidizing section 19 is provided to reduce the concentration of carbon monoxide in the reformed gas, and then the reformed gas having a sufficiently reduced carbon monoxide concentration is used as the fuel gas and the fuel cell 20 To prevent deterioration of the reforming catalyst. The allowable concentration of carbon monoxide in the fuel gas supplied to the fuel cell is about several percent or less for a phosphoric acid fuel cell and about several ppm or less for a polymer electrolyte fuel cell. It is. Hereinafter, a selective oxidation reaction of carbon monoxide that proceeds in the CO selective oxidation section 19 will be described.

CO + (１ ／) O ₂ → CO ₂ (7)

The CO selective oxidation section 19 has a platinum catalyst which is a carbon monoxide selective oxidation catalyst. Air is supplied from the blower 47 to the CO selective oxidizing unit 19 via the air supply path 52, and the supplied air is used to cause the selective oxidizing reaction of the above formula (7) to proceed. The reformed gas whose carbon monoxide concentration has been reduced in the CO selective oxidizing section 19 is supplied to the fuel cell 20 via the fuel supply path 53 as a fuel gas. Here, the concentration of carbon monoxide in the fuel gas obtained by passing the reformed gas through the CO selective oxidizing unit 19 is determined by the operating temperature of the CO selective oxidizing unit 19, the concentration of carbon monoxide in the supplied reformed gas, It is determined by the flow rate (space velocity) per unit catalyst volume of the reformed gas supplied to the CO selective oxidizing section 19 and the like. In this embodiment, the control unit 30 is connected to the fuel supply path 53.
A carbon monoxide sensor 49 connected to the fuel cell is provided to monitor the concentration of carbon monoxide in the fuel gas. The control unit 30 controls the reforming apparatus 1 estimated from the driving amount of the pump 68 described above.
The driving amount of the blower 47 is controlled based on the processing amount at 6 and the concentration of carbon monoxide in the fuel gas detected by the carbon monoxide sensor 49. Thus, the amount of oxygen supplied to the CO selective oxidizing section 19 is adjusted, the carbon monoxide concentration in the fuel gas is sufficiently reduced, and the supply of excessive oxygen to the CO selective oxidizing section 19 is prevented.

The fuel cell 20 receives the supply of the fuel gas generated by the reformer 16 and the oxidizing gas containing oxygen to perform an electrochemical reaction to obtain an electromotive force. This fuel cell 2
The electrochemical reaction that proceeds at 0 is the same as the reactions shown in the above-described equations (1) to (3). The fuel cell 20 of this embodiment is a polymer electrolyte fuel cell, and has a stack structure in which a plurality of unit cells 28 are stacked. FIG. 2 is a cross-sectional view schematically illustrating the configuration of the single cell 28. Single cell 28
Are the electrolyte membrane 21, the anode 22, and the cathode 23
And separators 24 and 25.

The anode 22 and the cathode 23 are gas diffusion electrodes having a sandwich structure sandwiching the electrolyte membrane 21 from both sides. The separators 24 and 25 form a flow path for the fuel gas and the oxidizing gas between the anode 22 and the cathode 23 while further sandwiching the sandwich structure from both sides. A fuel gas flow path 24P is formed between the anode 22 and the separator 24,
An oxidizing gas flow path 25P is formed between the oxidizing gas passage 25P and the separator 25.

Here, the electrolyte membrane 21 is a proton-conductive ion exchange membrane formed of a solid polymer material, for example, a fluorine-based resin, and shows good electric conductivity in a wet state. In this embodiment, a Nafion membrane (manufactured by DuPont) is used.
It was used. The surface of the electrolyte membrane 21 is coated with platinum as a catalyst or an alloy of platinum and another metal. As a method of applying the catalyst, a carbon powder supporting platinum or an alloy composed of platinum and another metal is prepared, and the carbon powder supporting the catalyst is dispersed in an appropriate organic solvent, and an electrolytic solution (eg, Aldrich Chemi) is used.
Cal Co., Nafion Solution) was added in an appropriate amount to form a paste, and screen printing was performed on the electrolyte membrane 21. Alternatively, a configuration is also preferable in which a sheet containing carbon powder supporting the above-described catalyst is formed into a film to form a sheet, and the sheet is pressed on the electrolyte membrane 21.

The anode 22 and the cathode 23 are both formed of carbon cloth woven with carbon fiber yarns. In the present embodiment, the anode 22 and the cathode 23 are formed of carbon cloth, but a configuration formed of carbon paper or carbon felt made of carbon fiber is also suitable.

The separators 24 and 25 are formed of a gas-impermeable conductive member, for example, dense carbon which is made of carbon by compressing carbon. Separator 2
The ribs 4 and 25 have ribs of a predetermined shape formed on the surface thereof.
And a surface of the fuel gas flow path 24P to form the separator 2
5 and the surface of the cathode 23 form an oxidizing gas flow path 25P. Here, the shape of the rib portion formed on the surface of each separator may be any shape as long as a gas flow path is formed and a fuel gas or an oxidizing gas can be supplied to the gas diffusion electrode. In this embodiment, the rib portions are formed in a plurality of grooves formed in parallel. Although the separator 24 and the separator 25 are described separately here, the actual fuel cell 20 has a configuration in which ribs are formed on both surfaces, and adjacent unit cells 28 share the separator.

The configuration of the single cell 28 which is the basic structure of the fuel cell 20 has been described above. When the fuel cell 20 is actually assembled, the anode 22, the electrolyte membrane 2
1, a plurality of single cells 28 are stacked with a separator disposed between the configurations of the cathode 23 (100 in this embodiment).
Pair), and a current collector plate composed of a dense carbon or copper plate is arranged at both ends to form a stack structure.

The fuel cell 20 described above is supplied with fuel gas via the fuel supply path 53 described above, and this fuel gas is introduced into the fuel gas flow path 24P on the anode side and is supplied to the above-mentioned electrochemical reaction. Is done. The fuel exhaust gas discharged from the fuel gas passage 24 </ b> P is supplied to the burner 15 via the fuel exhaust gas passage 60. In the burner 15, hydrogen remaining without being consumed by the electrochemical reaction is used as fuel for combustion.

Further, compressed air is supplied from the compressor 48 to the fuel cell 20 via the oxidizing gas supply path 59. The compressed air is introduced as an oxidizing gas into the oxidizing gas flow path 25P on the cathode side, and is subjected to the electrochemical reaction. The compressor 48 is connected to the control unit 30, and the control unit 30 controls the driving state of the compressor 48 according to the magnitude of the load connected to the fuel cell 20, the throughput of the reformer 16, and the like. , Fuel cell 20
The amount of oxidizing gas supplied to is adjusted. Oxidizing gas channel 2
The oxidized exhaust gas discharged from the 5P is introduced into the oxidized exhaust gas passage 61. The oxidizing exhaust gas introduced into the oxidizing exhaust gas passage 61 is discharged out of the fuel cell device 10. The oxidizing exhaust gas passage 61 is provided with a condenser 62, which condenses water vapor in the oxidizing exhaust gas. Oxidized exhaust gas is discharged after removal. In the condenser 62, the temperature of the oxidizing exhaust gas is lowered by a heat exchange section formed therein to lower the saturated vapor pressure, thereby condensing the water vapor in the oxidizing exhaust gas. The water condensed and recovered by the condenser 62 is supplied to the water recovery path 6.
4 and is returned to the water / methanol tank 14.

Here, the water vapor in the oxidizing exhaust gas is the above-mentioned generated water. As shown in the above-mentioned equation (2) of the electrochemical reaction, in the fuel cell 20, water is generated on the cathode side as the electrochemical reaction proceeds. In the fuel cell device 10 shown in FIG. 1, the air compressed by the compressor 48 is supplied to the fuel cell 20 as it is. Humidified compressed air may be supplied to the fuel cell 20 to prevent drying. In such a case, the oxidizing exhaust gas discharged to the oxidizing exhaust gas path 61 also contains water vapor previously added to the oxidizing gas. Been water
It is sent to the methanol tank 14.

A methanol addition path 66 is connected to the oxidation exhaust gas path 61, and the methanol tank 13
Can be added to the oxidation exhaust gas. A pump 67 connected to the control unit 30 is provided in the methanol addition path 66. When the pump 67 is driven by a drive signal from the control unit 30, a predetermined amount of methanol is added from the methanol tank 13 to the oxidized exhaust gas in the oxidized exhaust gas passage 61. This configuration corresponds to a main part of the present invention, and will be described later in detail.

Although not shown in FIG. 1,
The fuel cell 20 has a predetermined cooling water channel formed around it. The cooling water channel is a flow path filled with antifreeze, and the antifreeze flowing in the flow path circulates between the fuel cell 20 and a predetermined heat exchange unit. Although the above-described electrochemical reaction proceeds in the fuel cell 20, when such an electrochemical reaction proceeds, part of the chemical energy of the fuel supplied to the fuel cell 20 is not converted into electric energy. Is released as heat energy. Therefore, the fuel cell 2
The temperature 0 gradually increases during the operation, but in the present embodiment, the fuel cell 20 is kept in a predetermined temperature range by circulating the cooling water composed of the antifreeze.

The control unit 30 is configured as a logic circuit centered on a microcomputer. More specifically, the control unit 30 executes a predetermined operation or the like according to a preset control program. A ROM 36 in which necessary control programs, control data, and the like are stored in advance, and an R in which various data necessary for performing various arithmetic processing by the CPU 34 are temporarily read and written.
The AM 38 and the input / output port 32 for inputting detection signals from the various temperature sensors and pressure sensors described above and outputting drive signals to the various pumps and flow regulators described above in accordance with the calculation results of the CPU 34. Prepare.

Next, a description will be given of the control corresponding to the main part of the present embodiment, which is performed when the operation of the fuel cell device 10 is stopped. Fuel cell device 10 of the present embodiment
When the outside air temperature is low or the outside air temperature is predicted to decrease during the stoppage of the operation, the operation is started after adding methanol to the oxidized exhaust gas in the oxidized exhaust gas passage 61. Control to stop. Here, a state inside the oxidation exhaust gas passage 61 when the fuel cell device 10 is stopped will be described.

While the fuel cell device 10 is operating in a steady state, the oxidizing exhaust gas discharged to the oxidizing exhaust gas passage 61 is maintained in a predetermined temperature range corresponding to the operating temperature of the fuel cell 20. The water vapor in the oxidizing exhaust gas does not condense in a large amount in the flow path. However, since the temperature of the oxidizing exhaust gas gradually decreases as it passes through the oxidizing exhaust gas passage 61, the saturated vapor pressure in the oxidizing exhaust gas gradually decreases, and condensed water corresponding to the reduced vapor pressure becomes oxidized exhaust gas passage 6
Occurs during 1. The water droplets formed of the condensed water generated in the oxidizing exhaust gas passage 61 as described above are blown off by the oxidizing exhaust gas that is continuously discharged while the fuel cell device 10A is operating, and is eventually recovered in the condenser 62. Further, generated water retained in the oxidizing exhaust gas as water vapor without being condensed in the oxidizing exhaust gas passage 61 is also collected in the condenser 62.

In such a fuel cell device 10, when the supply of the raw fuel to the reformer 16 is stopped when the operation is stopped, and the fuel gas supplied to the fuel cell 20 starts decreasing, the fuel cell 20 The amount of heat generated decreases, and the temperature of the discharged oxidizing exhaust gas starts to decrease. When the temperature of the oxidizing exhaust gas starts to decrease in this way, the amount of condensed water generated in the oxidizing exhaust gas passage 61 increases. The fuel cell device 10 of the present embodiment prevents freezing of condensed water by adding methanol to the generated condensed water when the temperature in the flow channel decreases when the fuel cell device 10 is stopped. . As shown in FIG. 3, water has a freezing point of 0 ° C., whereas methanol has a low freezing point of −97.8 ° C. Therefore, by adding a predetermined amount of methanol to water, the coagulation temperature can be lowered, and freezing of condensed water in the flow path can be prevented.

FIG. 4 is a flowchart showing a stop processing routine executed when the operation of the fuel cell device 10 is stopped. When a stop of the operation of the fuel cell device 10 is instructed by a method such as an operator's input of an instruction to a predetermined operation switch, the control unit 30 executes the stop processing routine.

When this routine is executed, the CPU 34
First, it is determined whether or not to add methanol to the oxidizing exhaust gas in the oxidizing exhaust gas passage 61 (step S200). The determination as to whether or not to add methanol is made when the outside air temperature is equal to or lower than a predetermined temperature and the fuel cell device 1
This is a determination as to whether or not there is a possibility that condensed water generated in the fuel cell device 10 during the zero operation stop may freeze. Such a determination is made by inputting information about the outside air temperature to the control unit 30 via the outside air temperature sensor 65 provided in the fuel cell device 10 (see FIG. 1). If it is determined in step S200 that the addition of methanol is not to be performed, this routine is terminated as it is, and only the normal operation of stopping the operation is performed. As described above, in the present embodiment, it is configured to determine whether or not to add methanol in step S200. However, this step S200 is omitted, and when the operation of the fuel cell device 10 is stopped, the following processing for adding methanol is performed. It may be performed every time.

If it is determined in step S200 that methanol is to be added to the oxidizing exhaust gas path 61 due to the possibility of condensed water being frozen, the driving amount and driving time of the pump 67 and the compressor 48 are read. . (Step S210). The drive amount and drive time of the pump 67 and the compressor 48 are set based on the amount of methanol added to the oxidizing exhaust gas passage 61 and are values stored in the control unit 30 in advance. Based on the drive amount and the drive time, the pump 67 and the compressor 48
, A predetermined amount of methanol can be introduced into the oxidizing exhaust gas passage 61, and the concentration of methanol in the condensed water generated in the flow passage can be controlled to a predetermined range.

Here, the amount of methanol added to the oxidizing exhaust gas passage 61 is a value set as an amount that can sufficiently lower the freezing point of condensed water generated in the flow passage after the operation of the fuel cell device 10 is stopped. The range of the amount of condensed water generated in the flow path after the operation of the fuel cell device 10 is stopped depends on the amount of water generated on the cathode side of the fuel cell 20 operating in a steady state, the amount of humidifying oxidizing gas, or The prediction can be made based on the saturated vapor pressure at the temperature of the oxidizing exhaust gas discharged from the fuel cell 20 operating in the steady state, the volume of the flow path of the oxidizing exhaust gas, and the like. Based on these values, the amount of added methanol is set to be about 30% of condensed water.

After reading the drive amount and drive time of the pump 67 and the compressor 48 in step S210, the CPU 34 determines whether the fuel cell 20 has stopped operating (step S220). When the stop of operation of the fuel cell device 10 is instructed by a method such as an instruction input by an operator to a predetermined operation switch, the control unit 30 executes this routine and outputs a drive signal to the pump 68, thereby The supply of the raw fuel to the quality device 16 is stopped. When the supply of the raw fuel is stopped, the amount of processing in the reformer 16 is reduced, the amount of fuel gas supplied to the fuel cell 20 is reduced, and the supply of fuel gas is eventually stopped. When the supply of the fuel gas is stopped, the operation of the fuel cell 20 is stopped. The determination of the stop state of the fuel cell 20 in step S220 includes:
The determination can be made by inputting a temperature in the fuel cell 20 detected by providing a temperature sensor (not shown) in the fuel cell 20, an elapsed time after the pump 68 is stopped, and the like.

If it is determined in step S220 that the fuel cell 20 has stopped operating, then in step S21
The pump 67 and the compressor 48 are driven according to the value read at 0 (step S230). Thus, the supply of methanol to the oxidation exhaust gas passage 61 is started.
At this time, the oxidizing gas is continuously supplied to the oxidizing exhaust gas channel 61 by driving the compressor 48, and the oxidizing exhaust gas channel 6 is supplied by the flow of the oxidizing gas.
The methanol supplied into 1 moves in the downstream direction of the flow path while mixing with the condensed water in the oxidation exhaust gas path 61. Since the oxidation exhaust gas path 61 is connected to the condenser 62,
The condensed water inside also becomes mixed with methanol. Since the condensed water in the condenser 62 is recovered in the water / methanol tank 14 through the water recovery path 64, the oxidizing exhaust gas path 61, the condenser 62 and the condenser 62 are driven by driving the pump 67 and the compressor 48 as described above. Water recovery path 64
The condensed water in each of them contains methanol.

In step S230, the pump 6
When the compressor 7 and the compressor 48 start to be driven, the measurement of the elapsed time is started. That is, the CPU 34
Resets the timer and sets the variable t representing the elapsed time to 0.
Is substituted (step S240). Thereafter, the operation of reading the value of t (step S250) and comparing it with a predetermined reference time t0 stored in advance (step S260) is repeated until the reference time t0 elapses. Here, the predetermined reference time t0 corresponds to step S2.
10 corresponds to the read driving time.

If it is determined in step S260 that the elapsed time t has exceeded the reference time t0, the oxidation exhaust gas passage 6
The operation of the pump 67 and the compressor 48 is stopped (step S270), assuming that a sufficient amount of methanol has been supplied into 1 and has been sufficiently mixed with the condensed water in the flow path (step S270), and this routine ends.

While the operation of the fuel cell device 10 is stopped, the oxidizing exhaust gas passage 61 and the condenser 6 are stopped.
2 and the water recovery passage 64, the condensed water containing the predetermined amount of methanol remains. Next time fuel cell device 1
When the operation at 0 is restarted, the condensed water containing methanol is sent to the water / methanol tank 14 where it is stored and supplied again to the reformer 16 as raw fuel.

According to the fuel cell device 10 of the first embodiment configured as described above, methanol is added to the oxidizing exhaust gas when the operation of the fuel cell device 10 is stopped. Is left in the oxidation exhaust gas passage 61, the condenser 62 and the water recovery passage 64. Therefore, even if the outside air temperature decreases while the operation of the fuel cell device 10 is stopped, the condensed water does not freeze in the oxidation exhaust gas passage 61, the condenser 62, and the water recovery passage 64. Therefore, there is no possibility that the frozen condensed water narrows or partially blocks the flow paths of the oxidation exhaust gas and the condensed water. When the operation of the fuel cell device 10 is restarted next time,
There is no need to heat the flow path such as the oxidizing exhaust gas path 61 to dissolve the frozen condensed water, which may require a long time when the operation is restarted or wastefully consumes energy for heating. Absent.

FIG. 5 shows the time (start-up time) required for starting the conventionally known fuel cell device, the time required for melting the condensed water frozen in the flow path by heating, and the time required for this embodiment. FIG. 4 is an explanatory diagram showing a state in which a time required for starting the fuel cell device 10 is compared with the time required. As shown in FIG. 5, in a conventionally known fuel cell device, a predetermined time is required to melt condensed water in a flow path at the time of startup. Melting of the condensed water can be performed, for example, by disposing a heater for heating in a flow path in which the condensed water is expected to remain, and energizing the heater to generate heat at startup. . The start-up time at this time is mainly a time for melting the condensed water frozen in the flow path by the heat generated by the heater. Alternatively, frozen condensed water may be thawed by using combustion exhaust gas generated by a burner provided in the reformer. In this case,
Methanol is supplied from the methanol tank to the burner to cause a combustion reaction, and the amount of heat generated here is transmitted to the flow path to melt the condensed water. These processes include:
It takes considerable time. On the other hand, in the fuel cell device 10 according to the first embodiment, at the time of startup, there is no possibility that the gas flow path is blocked. The supply of gas can be started in this manner, and no time is required for melting the condensed water.

In the oxidizing exhaust gas passage 61 of the fuel cell device 10 according to the present embodiment, it is desirable that the connection position of the methanol addition passage 66 be as upstream of the oxidizing exhaust gas passage 61 as possible. When the operation of the fuel cell device 10 is stopped, the temperature of the oxidizing exhaust gas discharged from the fuel cell 20 gradually decreases, so that the pressure in the oxidizing exhaust gas passage 61 becomes slightly negative and is blown into the oxidizing exhaust gas passage 61 from the methanol addition passage 66. Methanol easily diffuses in the oxidation exhaust gas passage 61.
However, in the oxidation exhaust gas passage 61, the fuel cell 2
In order to sufficiently achieve the freezing prevention effect up to the vicinity of the connection portion with zero, it is desirable that the connection position of the methanol addition passage 66 is further upstream in the oxidation exhaust gas passage 61. Further, in the oxidizing exhaust gas passage 61, in order to secure the above-mentioned anti-freezing effect over the downstream side where the condenser 62 is disposed, the methanol addition passage 66 is branched on the way, and a part of the methanol to be added is further downstream. It may be added from the side.

In step S200 of the stop processing routine of the first embodiment, whether or not to add methanol to the oxidized exhaust gas is determined based on the outside air temperature of the fuel cell device 10 when the operation is stopped. However, the determination may be made based on whether or not the outside air temperature is expected to decrease to a temperature below freezing while the operation of the fuel cell device 10 is stopped. In such a determination, a period in which freezing is expected is set in the control unit 30 in advance (for example, 1
As in February 1 to February 31, etc.), the control unit 30
It can be executed by a method of reading the date and time from a timer (not shown) and judging whether or not it corresponds to the above-mentioned preset period. Alternatively, condensed water may freeze when data on the outside air temperature is input from the above-described outside air temperature sensor and the condition on the outside air temperature becomes a predetermined condition (for example, the average air temperature falls below a certain value for a predetermined period). May be determined. When the fuel cell device 10 of this embodiment is used as a mobile power source such as a power source for driving an electric vehicle, a predetermined switch is provided to directly instruct the user to add methanol to the oxidized exhaust gas. It is also preferable to provide an input-capable configuration in a case where the device is used by moving to a cold region.

In the fuel cell device 10 of the first embodiment,
In order to supply air to the burner 15, the CO selective oxidizing section 19 and the fuel cell 20, the blowers 45 and 47 and the compressor 48 are provided, respectively. ,
The same blower or compressor may be used to supply air to at least two or more. In this case, if a valve is provided in the flow path of the air supplied from the blower or the compressor and the open state of the valve is controlled, a required amount of air can be supplied to each of the valves. .

In the first embodiment, the fuel cell device 1
Although the configuration is such that methanol is supplied to the oxidizing exhaust gas channel 61 when the operation is stopped, the configuration may be such that methanol is always supplied to the oxidizing exhaust gas channel 61 during operation of the fuel cell device. Such a configuration is described below as a second embodiment. The control performed in the second embodiment is executed by a fuel cell device having the same configuration as the fuel cell device 10 of the first embodiment shown in FIG. FIG. 6 is a methanol addition processing routine performed in the fuel cell device 10 of the second embodiment. In this methanol addition processing routine, the operation of the fuel cell device 10 is started, and the fuel cell 2
When it is determined from the operating temperature of 0 or the like that the fuel cell device 10 has reached the steady state, the process is executed by the CPU 34 every predetermined time.

When the methanol addition processing routine is executed, first, the CPU 34 calculates the amount of water generated in the oxidizing exhaust gas discharged from the fuel cell 20 (step S30).
0). The amount of water generated in the oxidized exhaust gas depends on the fuel cell 20
Is calculated as the flow rate discharged from the fuel cell 20 based on the load connected to the fuel cell 20, that is, the amount of power generated by the fuel cell 20 and the amount of water vapor added to the oxidizing gas supplied to the fuel cell 20.

After calculating the amount of generated water in the oxidizing exhaust gas in step S300, the CPU 34 determines the amount of methanol to be supplied to the oxidizing exhaust gas passage 61 based on the calculated amount of generated water (step S310). In the present example, the amount of added methanol was determined as the flow rate of added methanol with respect to the flow rate of the generated water calculated in step S300 such that the amount of added methanol was 30% of the amount of generated water.

When the flow rate of added methanol is determined,
The PU 34 outputs a drive signal to the pump 67 (Step S320). The drive amount of the pump 67 driven in response to the drive signal is a drive amount capable of adding methanol to the oxidation exhaust gas passage 61 in accordance with the flow rate of added methanol determined in step S310. Here, the output of the drive signal to the pump 67 causes the drive of the pump 67 to start when the operation of the fuel cell device 10 is started, but the pump 67 is output when the operation of the fuel cell device 10 is continued.
Is instructed to change or maintain the drive amount. When the drive signal is output to the pump 67 in step S320, the present routine ends.

According to the fuel cell system of the second embodiment constructed as described above, a predetermined amount of methanol is always added to the oxidizing exhaust gas during the operation of the fuel cell device 10, so that the oxidizing exhaust gas passage 61, condenser 62 and water recovery path 6
The condensed water present in 4 will always contain a predetermined proportion of methanol. Therefore, similarly to the first embodiment, even when the outside air temperature is reduced while the operation of the fuel cell device 10 is stopped, the condensed water freezes in the oxidation exhaust gas passage 61, the condenser 62, and the water recovery passage 64. I won't. Therefore, there is no possibility that the frozen condensed water narrows or partially blocks the flow paths of the oxidation exhaust gas and the condensed water. Since the condensed water does not freeze, there is no need to heat the flow path such as the oxidizing exhaust gas path 61 to dissolve the frozen condensed water when the operation of the fuel cell device 10 is restarted next time. Sometimes, it does not take a long time or waste energy for heating.

Further, in the fuel cell devices 10 of the first and second embodiments, methanol is added to the condensed water in order to lower the melting point of the condensed water, which is the raw fuel for generating the fuel gas. Since methanol can be used as it is, there is no need to provide a special configuration for lowering the melting point of condensed water. Further, in the raw fuel storage device 12 of the present embodiment, the water to be subjected to the steam reforming reaction together with the methanol is stored in the water / methanol tank 14 in a state of being mixed with the methanol. Therefore, the methanol added to the oxidized exhaust gas is recovered through the condenser 62 and the water recovery path 64, and stored as it is in the water / methanol tank 14 together with the generated water. Therefore, the configuration of the fuel cell device can be simplified, and there is no need to separate and collect methanol, which is an antifreezing agent, from condensed water.

In the first and second embodiments, the amount of methanol added to the oxidizing exhaust gas is about 30% of the oxidizing exhaust gas amount.
However, a different ratio of methanol may be added to the oxidation exhaust gas. Since the freezing point of the condensed water decreases as the proportion of methanol added increases, freezing can be prevented even when the outside air temperature is lower. Of course, if the decrease in the outside air temperature is expected to be within a predetermined range, the ratio of the added methanol may be smaller than the value shown in the embodiment.

The fuel cell devices of the first and second embodiments use methanol as a raw fuel for producing a hydrogen-rich fuel gas, and supply this methanol to the oxidizing exhaust gas passage 61 to thereby oxidize the oxidizing exhaust gas. Although the configuration is such that condensed water is prevented from freezing in the passage 61, a raw fuel other than methanol may be applied to the above configuration. As a usable raw fuel, it is sufficient that a hydrogen-rich gas can be generated by a reforming reaction and can be easily mixed with water, and an alcohol-based hydrocarbon such as ethanol or isopropanol can be used.

In the first and second embodiments described above,
By adding methanol to the oxidizing exhaust gas, the oxidizing exhaust gas passage 61, the condenser 62, and the water recovery passage 64 are formed.
Although the freezing point of the condensed water inside was lowered to prevent freezing of the condensed water remaining in the flow passage, the condensed water was discharged by discharging the condensed water from the flow passage when the operation of the fuel cell was stopped. Freezing can also be prevented. Such a configuration will be described below as a third embodiment. Since the fuel cell device 10A of the third embodiment has substantially the same configuration as the fuel cell devices 10 of the first and second embodiments, common components are denoted by the same reference numerals and detailed description thereof will be omitted. Omitted.

The fuel cell device 10A according to the third embodiment has a drain 70 in the oxidized exhaust gas passage 61, the condenser 62 and the water recovery passage 64 as a structure for discharging condensed water from the flow passage. The drain 70 is provided at a predetermined position in the oxidizing exhaust gas passage 61, the condenser 62, and the water recovery passage 64, and when the operation of the fuel cell device 10A is stopped,
This is a device for storing and discharging condensed water generated in these flow paths. As described above, the drain 70 is provided in each of the above-described flow paths. Hereinafter, the drain 70 provided in the oxidation exhaust gas path 61 will be described.

FIG. 7 shows a fuel cell device 10A according to the third embodiment.
The outline of the configuration of the drain 70 in the oxidation exhaust gas path 61 provided in the apparatus is shown. The drain 70 is provided in the oxidizing exhaust gas passage 61 at a position where the flow passage is bent and lower in accordance with the shape of the flow passage. The drain 70 includes a water reservoir 72,
An outlet 74 and a valve 76 are provided. Water storage 72
Is formed as a structure in which the bottom of the pipe at a predetermined position of each of the flow paths is depressed, so that an amount of condensed water according to the shape of the water storage section 72 can be stored. Outlet 74
Is an opening provided at the bottom of the water storage 72, and is provided with a valve 76. The valve 76 is configured as an electromagnetic valve, is connected to the control unit 30, and opens and closes the discharge port 74 in response to a drive signal from the control unit 30. The fuel cell device 10A of the present embodiment stores the condensed water generated in the water storage portion 72 in the drain 70 when the temperature in the flow path decreases when the fuel cell device 10A is stopped, and then opens the valve 76. To remove condensed water from the drain 70. Hereinafter, such an operation when the operation of the fuel cell device 10A is stopped will be described.

FIG. 8 shows a fuel cell device 10A according to the third embodiment.
9 is a flowchart illustrating a stop-time processing routine executed when the operation of FIG. When a stop of the operation of the fuel cell device 10A is instructed by a method such as an operator's input of an input to a predetermined operation switch, the control unit 30 executes the stop processing routine.

When this routine is executed, the CPU 34
First, the operation of the pump 68 is stopped by outputting a signal to the pump 68 provided in the raw fuel supply path 50, and the supply of the raw fuel from the water / methanol tank 14 to the reformer 16 is stopped ( Step S400). When the supply of the raw fuel to the reforming device 16 is stopped, the throughput of each part configuring the reforming device 16 starts to decrease as described above. Next, the CPU 34 resets a predetermined timer provided inside the control unit 30 (step S410). That is,
By substituting 0 into a variable t representing time, measurement of time after the stop of operation of the fuel cell device 10 is instructed is started.

Next, the CPU 34 controls the fuel cell device 10A.
The elapsed time t from when the stop of the operation is instructed is read from the timer (step S420) and compared with a predetermined value t1 set in advance (step S430). Here, the value of t1 is determined as follows: after the operation of the fuel cell device 10A is instructed to stop, the temperature in the flow path of the oxidized exhaust gas is sufficiently lowered, and the water generated in the oxidized exhaust gas is condensed and stored in the drain 70. It is set as the time required for the state to be performed. In this embodiment, the value of T1 is set to 30 minutes.

If it is determined in step S430 that the elapsed time t has exceeded the time t1, the CPU 34 outputs a drive signal to the valve 76 to open the valve 76 for a predetermined time (step S440). As a result, the condensed water stored in the water storage section 72 of the drain 70 is discharged out of the fuel cell device 10A. In step S440, when the valve 76 is opened to discharge the condensed water, this routine ends.

According to the fuel cell device 10A of the third embodiment configured as described above, when the fuel cell device 10A is stopped, the condensed water generated in the pipe together with the temperature drop is discharged to the drain 7
0 is stored in the water storage section 72. Here, after a predetermined time has elapsed after the operation of the fuel cell device 10A has stopped, the condensed water is discharged from the drain 70 by opening the valve 76.
After the operation of A is stopped, condensed water does not remain in the flow path of the oxidation exhaust gas. Therefore, the fuel cell device 10
Even when the outside air temperature decreases after the operation of A is stopped, the above-described inconvenience caused by the freezing of the condensed water in the flow path does not occur. Further, since there is no possibility that the condensed water is frozen in the flow path, when the operation of the fuel cell device 10A is restarted next time, it is not necessary to heat the oxidized exhaust gas path 61 to dissolve the frozen condensed water, There is no need to take a long time when restarting the operation, nor waste energy for heating.

In the oxidizing exhaust gas channel 61 of the fuel cell device 10A of this embodiment, the drain 70 is provided at a position where the flow channel is bent and low depending on the shape of the flow channel. The condensed water generated inside is easily guided into the water storage 72 according to the shape of the flow path. Here, the drain 70 provided in the oxidation exhaust gas passage 61
May be determined according to the shape of the oxidizing exhaust gas passage 61 and the length of the flow passage. If the length of the oxidizing exhaust gas passage 61 is sufficiently short, only one drain 70 may be provided. Further, as described above, when it is difficult to guide the condensed water into the drain 70 only by the shape of the oxidation exhaust gas passage 61, the driving of the compressor 48 is continued even after the power generation in the fuel cell 20 is stopped, and the valve 76 is turned off. Until the opening, the oxidizing gas may be supplied into the oxidizing exhaust gas passage 61 to guide the condensed water into the water storage 72.

In the above-described embodiment, the drain 70 provided in the oxidizing exhaust gas passage 61 has been described. However, in the fuel cell device 10A of the present embodiment, the predetermined flow passage in the condenser 62 and the water recovery passage 64 are similarly provided. A drain 70 is provided at the position. That is, the condenser 62 and the water recovery path 6
4, the drain 70 is provided at a position where the flow path is bent and low as in the case of the oxidation exhaust gas path 61. When the operation of the fuel cell device 10A is stopped, the condensed water is discharged from the flow path and the condensed water is discharged. Is configured to prevent inconvenience caused by freezing.

Alternatively, in the configuration of the third embodiment, the drain 70 may not be provided in the water recovery path 64, and freezing of condensed water in the water recovery path 64 may be allowed. Oxidation exhaust gas path 61 and condenser 62
Are flow paths through which the oxidized exhaust gas discharged from the fuel cell 20 passes, and if these flow paths are blocked by frozen condensed water, supply of the oxidizing gas to the fuel cell 20 will be hindered. . Therefore, the fuel cell device 1
At the time of starting at 0, it is essential that these gas flow paths are not closed. On the other hand, since the water recovery path 64 is not a flow path through which the oxidizing exhaust gas passes,
Even when the flow path is blocked by the frozen condensed water, the configuration may be such that the condensed water frozen in the water recovery path 64 is melted after the operation of the fuel cell device 10 is started. .

In the third embodiment, the condensed water is discharged from the drain 7
Although the condensed water is removed from the inside of the flow channel by discharging from the discharge port 74 of the drain 70 after being stored at 0, a high-temperature gas is introduced into the oxidation exhaust gas passage 61 when the operation of the fuel cell device is stopped, and A configuration may be adopted in which condensed water is removed from the inside of the flow path by drying the inside of the exhaust gas path 61. In other words, the condensed water in the flow path may be vaporized by the introduced high-temperature gas and discharged out of the fuel cell device together with the high-temperature gas to prevent the condensed water from freezing in the flow path. Hereinafter, as a fourth embodiment, a configuration will be described in which exhaust gas discharged from a heating device provided in a reformer is used as the high-temperature gas.

FIG. 9 shows a fuel cell device 10B according to the fourth embodiment.
FIG. 3 is an explanatory diagram showing the configuration of FIG. The fuel cell device 10B includes:
Since the fuel cell apparatus 10 has almost the same configuration as the fuel cell apparatus 10 of the first embodiment, the same reference numerals are given to the common elements, and detailed description is omitted. Only the following will be described.

The fuel cell device 10B according to the fourth embodiment has the first
The methanol addition path 6 provided in the fuel cell device 10 of the embodiment
6 is provided, instead, a combustion gas introduction passage 69 for introducing the combustion exhaust gas discharged from the evaporating section 17 into the oxidation exhaust gas passage 61 is provided. The combustion gas introduction passage 69 branches from the combustion gas branch passage 58 and is connected to an upstream portion of the oxidation exhaust gas passage 61. The combustion gas introduction passage 69 is provided with a valve 69B. When the valve 69B is opened, combustion exhaust gas can be supplied to the oxidation exhaust gas passage 61. Here, the valve 69B is connected to the control unit 30, and is opened and closed by a drive signal output from the control unit 30.

FIG. 10 shows a fuel cell device 10 according to the fourth embodiment.
6 is a flowchart illustrating a stop processing routine executed when the operation is stopped in B. When the stop of the operation of the fuel cell device 10B is instructed by a method such as an instruction input by an operator to a predetermined operation switch, the control unit 30 executes the stop time processing routine.

When this routine is executed, the CPU 34
First, the operation of the pump 68 is stopped by outputting a signal to the pump 68 provided in the raw fuel supply path 50, and the supply of the raw fuel from the water / methanol tank 14 to the reformer 16 is stopped ( Step S500). When the supply of the raw fuel to the reforming device 16 is stopped, the throughput of each part configuring the reforming device 16 starts to decrease as described above. Next, a drive signal is output to the valve 55A and the valve 69B, the valve 55A is closed, the valve 69B is opened, and the flow path of the combustion exhaust gas discharged from the burner 15 is changed (Step S510). . Step S510
, The high-temperature combustion exhaust gas discharged from the burner 15 is introduced into the oxidizing exhaust gas passage 61 via the evaporator 17.

Next, the CPU 34 resets a predetermined timer provided inside the control section 30 (step S52).
0). That is, by substituting 0 into a variable t representing time, measurement of time after the stop of operation of the fuel cell device 10 is instructed is started. Further, a drive signal is output to the valve 44 to open the valve 44 (step S530). By opening the valve 44, the supply of methanol from the methanol tank 13 to the burner 15 is started. When the supply of the raw fuel to the reformer 16 is stopped in step S500 described above, the amount of fuel gas supplied to the fuel cell 20 also starts to decrease, and accordingly, the amount of power generated by the fuel cell 20 decreases. At the same time, the combustion exhaust gas supplied from the fuel cell 20 to the burner 15 also starts to decrease. In step S530, the valve 44 is opened and the supply of methanol to the burner 15 is started to secure fuel for combustion in the burner 15, and a sufficient amount of high-temperature combustion exhaust gas is discharged from the burner 15. to continue.

By introducing the high-temperature combustion exhaust gas in this way, the condensed water generated in the pipe in the oxidation exhaust gas passage 61 is heated and vaporized. The vaporized condensed water is
The combustion exhaust gas guides the condenser 62 to the condenser 62.
2 is discharged to the outside of the fuel cell device 10B together with the combustion exhaust gas. At this time, the condensed water remaining in the condenser 62 is also vaporized by the combustion exhaust gas and the fuel cell device 10
It is discharged outside B.

It is desirable that the position where the combustion gas introduction passage 69 is connected to the oxidizing exhaust gas passage 61 is located on the more upstream side (on the side of the connection with the fuel cell 20). Thereby, the dry state of the whole oxidation exhaust gas passage 61 can be made more satisfactory.

Next, the CPU 34 reads the elapsed time t from the stop of the operation of the fuel cell device 10B from the timer (step S540) and compares it with a predetermined value t2 (step S540). S550). Here, the value of t2 is such that after the introduction of the combustion exhaust gas into the oxidizing exhaust gas passage 61, the condensed water in the oxidizing exhaust gas passage 61 and the condenser 62 is vaporized and these passages are sufficiently dried. Is set as the time required. This value may be appropriately set depending on the shape and length of the flow channel.

If it is determined in step S550 that the elapsed time t has exceeded the time t2, the CPU 34 outputs a drive signal to the valve 44 to close the valve 44 (step S560). Thus, the supply of methanol to the burner 15 is stopped, and the combustion reaction in the burner 15 ends. After execution of step S560, the CPU
34 ends this routine.

According to the fuel cell device 10B of the fourth embodiment configured as described above, when the fuel cell device 10B is stopped, the condensed water generated in the oxidizing exhaust gas passage 61 and the condenser 62 is subjected to high-temperature combustion. After being vaporized by the exhaust gas, it is discharged outside the fuel cell device 10B. Therefore, even when the outside air temperature decreases after the operation of the fuel cell device 10B is stopped, the above-described inconvenience caused by the freezing of the condensed water in the flow path does not occur. Further, since there is no possibility that the condensed water freezes in the flow path, the fuel cell device 1
When the operation of OB is restarted, it is not necessary to heat the flow path such as the oxidizing exhaust gas path 61 to dissolve the frozen condensed water, and it takes a long time to restart the operation or wastes energy for heating. No consumption.

The fuel cell device 10B of the fourth embodiment described above.
Then, in order to dry the inside of the oxidation exhaust gas passage 61, the burner 1
Although the combustion exhaust gas discharged from the burner 15 is used, a gas other than the combustion exhaust gas discharged from the burner 15 may be used as long as it is a high-temperature gas capable of sufficiently raising the temperature in the oxidation exhaust gas passage 61. As long as the gas is discharged from the high-temperature portion provided in the device including the fuel cell device 10B and has a calorific value enough to vaporize condensed water, the same effects as those of the above-described embodiment can be obtained. be able to.

In the fourth embodiment, since the combustion exhaust gas discharged from the burner 15 is introduced into the oxidizing exhaust gas passage 61, it is possible to remove the water generated in the oxidizing exhaust gas passage 61 and the condenser 62. However, by introducing the combustion exhaust gas into the water recovery passage 64, it is also possible to remove generated water in the water recovery passage 64. FIG. 11 shows a fuel cell device 10C having such a configuration.

The fuel cell device 10C shown in FIG. 11 has a combustion gas introduction passage 69 in addition to the structure of the fuel cell device 10B.
And a combustion gas branch 80 branching from the fuel gas. The combustion gas branch 80 is connected to the water recovery passage 64, and the combustion exhaust gas supplied from the burner 15 can be introduced into the water recovery passage 64 by the combustion gas branch 80. When the operation of the fuel cell device 10C having such a configuration is stopped, if a routine similar to the stop processing routine shown in FIG. 10 is executed, the valve 55A is closed by the processing corresponding to step S510, and the valve 69B is opened. When opened, the combustion exhaust gas discharged from the burner 15 is introduced into the water recovery passage 64 together with the oxidized exhaust gas passage 61. By introducing the combustion exhaust gas into the flow path in this way, the oxidation exhaust gas path 61, the condenser 62, and the water recovery path 64
Most of the condensed water inside is vaporized and the fuel cell device 10C
It is released to the outside and the inside of the above-mentioned flow path can be sufficiently dried.

Although not described in the stop-time processing routines (see FIGS. 8 and 10) of the third and fourth embodiments described above, when executing these stop-time processing routines, FIG. It is desirable to first determine whether or not to perform an operation for preventing freezing of the flow path, similarly to the stop processing routine in the fuel cell device 10 of the first embodiment shown in FIG. That is, similarly to step S200 in FIG. 4, the outside air temperature when the fuel cell device is stopped, data on the outside air temperature (e.g., average air temperature), information on a previously stored freezing period, By judging the presence or absence of a direct instruction input, it is judged whether or not to drain water from the drain or introduce combustion exhaust gas into the flow path. With such a configuration, at a time when there is no possibility of freezing, consumption of energy required for the above-described operation for preventing freezing can be suppressed.

In the first and second embodiments described above, the freezing point of the condensed water remaining in the flow path of the oxidized exhaust gas is reduced to prevent freezing of the condensed water, and in the third and fourth embodiments, the oxidized exhaust gas is prevented from freezing. Freezing was prevented by removing condensed water from the inside of the flow path. With such a configuration, it is possible to prevent the inconvenience that the condensed generated water freezes in the flow channel and blocks the flow channel. In the following, as a fifth embodiment, a gas flow path can be secured even when condensed water is frozen in the flow path by providing a water capturing means for capturing the condensed water on the inner surface of the conduit forming the flow path. The following shows the configuration.

The fuel cell device 10D according to the fifth embodiment includes the first
Since the fuel cell device 10 has substantially the same configuration as the fuel cell device 10 of the embodiment, the same components are denoted by the same reference numerals, and detailed description thereof will be omitted. The fuel cell device 10D includes the fuel cell device 10
Unlike the methanol tank 13, the oxidation exhaust gas passage 61
There is no methanol addition path 66 for supplying methanol to the filter. The oxidizing exhaust gas path 6 in the fuel cell device 10D
1, the condenser 62 and the water recovery path 64
It has a mesh structure as water supplement means.

FIG. 12 is a sectional view schematically showing the structure of the oxidizing exhaust gas passage 61. As shown in FIG. As shown in FIG. 12, the oxidizing exhaust gas channel 61 includes a mesh portion 82 over the inner wall surface. The mesh portion 82 is provided in the oxidation exhaust gas passage 61.
This is a mesh structure for retaining condensed water generated inside the pipe wall surface of the oxidation exhaust gas passage 61. In this embodiment, the mesh portion 82 is made of foamed nickel formed so that the roughness of the mesh is about 0.5 mm. In the oxidizing exhaust gas path 61 having such a mesh portion 82,
When the condensed water is generated inside, the generated condensed water spreads along the inside of the mesh portion 82 by capillary action. Although the configuration of the oxidizing exhaust gas passage 61 is shown in FIG. 12, the mesh portion 82 similar to the oxidizing exhaust gas passage 61 is formed on the inner wall surface of the flow channel configuring the condenser 62 and the water recovery channel 64. .

According to the fuel cell device 10D of the fifth embodiment configured as described above, when the outside air temperature drops after the operation of the fuel cell device 10D is stopped and condensed water remaining in the flow path freezes. However, the condensed water only freezes while being held in the mesh portion 82, and the frozen condensed water does not block the pipes forming the oxidizing exhaust gas path 61, the condenser 62, and the water recovery path 64. Absent. Therefore, when the operation of the fuel cell device 10D is restarted next time, it is not necessary to heat the flow path such as the oxidation exhaust gas path 61 to dissolve the frozen condensed water, and it takes a long time to restart the operation, Energy is not wasted for heating.

In the fifth embodiment, the mesh portion 82 is made of foamed nickel. However, the mesh portion 82 can be formed into a mesh structure having a roughness capable of retaining condensed water on the pipe surface. The mesh portion 82 may be formed of another material as long as the material is stable against the temperature of the oxidizing exhaust gas during operation or the oxidizing exhaust gas. For example, it is also preferable that the mesh portion 82 be formed of a foamed urethane plated with nickel. Here, the pipe forming the oxidizing exhaust gas path 61 may be any material that is stable to the temperature of the oxidizing exhaust gas during operation of the fuel cell 20 and the oxidizing exhaust gas.
In this embodiment, the oxidation exhaust gas passage 61 is formed of stainless steel.

In the fuel cell devices of the first to fifth embodiments described above, the solid polymer electrolyte type fuel cell is provided as the fuel cell. However, as the electrochemical reaction proceeds, generated water is supplied to the cathode side. The same effect can be obtained with other types of fuel cells as long as condensed water remains in the oxidation exhaust gas passage. Alternatively, in a fuel cell that generates water on the anode side as the electrochemical reaction proceeds, such as a solid oxide fuel cell using a solid electrolyte having oxide ion conductivity, the above-described configuration is used in the fuel exhaust gas passage. By applying, it is possible to prevent inconvenience caused by freezing of condensed water in the flow path.

The embodiments of the present invention have been described above.
The present invention is not limited to such embodiments at all, and it goes without saying that the present invention can be implemented in various modes without departing from the gist of the present invention.

[Brief description of the drawings]

FIG. 1 shows a fuel cell device 1 according to a preferred embodiment of the present invention.
FIG. 2 is a block diagram schematically illustrating a configuration of a zero.

FIG. 2 is a schematic cross-sectional view showing a configuration of a single cell 28 included in the fuel cell 20.

FIG. 3 is an explanatory diagram showing a coagulation temperature of water and methanol.

FIG. 4 is a flowchart illustrating a stop processing routine executed in the fuel cell device 10 according to the first embodiment.

FIG. 5 is an explanatory diagram showing a state in which the startup time required at the time of starting is compared between the fuel cell device 10 of the first embodiment and the conventional fuel cell device.

FIG. 6 is a flowchart illustrating a methanol addition processing routine executed in the fuel cell device 10 according to the second embodiment.

FIG. 7 is an explanatory diagram showing a configuration of a drain 70.

FIG. 8 is a flowchart illustrating a stop processing routine executed in a fuel cell device 10A according to a third embodiment.

FIG. 9 is an explanatory diagram schematically showing a configuration of a fuel cell device 10B according to a fourth embodiment.

FIG. 10 is a flowchart illustrating a stop processing routine executed in a fuel cell device 10B according to a fourth embodiment.

FIG. 11 is an explanatory diagram schematically showing a configuration of a fuel cell device 10C.

FIG. 12 is a schematic sectional view illustrating a configuration of an oxidation exhaust gas passage 61 in a fuel cell device 10D according to a fifth embodiment.

[Explanation of symbols]

 10, 10A to 10D: fuel cell device 12: raw fuel storage device 13: methanol tank 14: water / methanol tank 15: burner 16: reformer 17: evaporator 18: reformer 19: CO selective oxidizer 20 Fuel cell 21 ... Electrolyte membrane 22 ... Anode 23 ... Cathode 24, 25 ... Separator 24P ... Fuel gas flow path 25P ... Oxidizing gas flow path 28 ... Single cell 30 ... Control unit 32 ... Input / output port 34 ... CPU 36 ... ROM 38 ... RAM 40 ... Flow path 41 ... Valve 42 ... Specific gravity sensor 43 ... Methanol flow path 44 ... Valves 45, 47 ... Blower 46 ... Air supply path 48 ... Compressor 49 ... Carbon monoxide sensor 50 ... Raw fuel supply path 51, 52 ... Gas Flow path 52 Air supply path 53 Fuel supply path 54 Combustion gas supply path 55 Combustion gas path 56 Combustion gas path 57 Burning gas path 58 ... Combustion gas branch path 55A, 58A ... Valve 59 ... Oxidizing gas supply path 60 ... Fuel exhaust gas path 61 ... Oxidizing exhaust gas path 62 ... Condenser 64 ... Water recovery path 66 ... Methanol addition path 67, 68 ... Pump 69 ... combustion gas introduction path 69B ... valve 70 ... drain 72 ... water storage section 74 ... discharge port 76 ... valve 80 ... combustion gas branch path 82 ... mesh part

Claims (16)

[Claims] 1. A fuel cell device which receives a supply of fuel on an anode side and a supply of an oxidizing gas containing oxygen on a cathode side to obtain an electromotive force by an electrochemical reaction. Blockage preventing means for preventing blockage of the gas flow path due to freezing of the generated water present in the gas flow path during operation stop of the fuel cell device, in the gas flow path connected to the electrode on which the generated water is generated A fuel cell device comprising: 2. The fuel cell device according to claim 1, wherein the blockage prevention means is a freeze prevention means for preventing freezing of the generated water in a gas flow path connected to an electrode side on which the generated water is generated. 3. The fuel cell device according to claim 2, wherein the fuel supplied to the anode side is a fuel generated from an alcohol-based hydrocarbon as a raw fuel, and the anti-freezing means includes A fuel cell device comprising raw fuel mixing means for supplying the raw fuel to a gas flow path connected to the electrode side where the generation of the raw fuel occurs. 4. The fuel cell device according to claim 3, wherein at least a part of the raw fuel composed of the alcohol-based hydrocarbon is mixed with water required for producing the fuel from the raw fuel. And a water / raw fuel storage unit for preparing the fuel, and condensing the generated water in a gas flow path connected to an electrode side on which the generated water is generated.
A fuel cell apparatus comprising: a generated water recovery unit that recovers the raw fuel in a raw fuel storage unit. 5. The fuel cell device according to claim 3, wherein the alcohol-based hydrocarbon is methanol. 6. The fuel cell device according to claim 2, wherein the freeze prevention means is a water removing means for removing the generated water from a gas flow path connected to an electrode side on which the generated water is generated. 7. The water removal means is a water storage part formed in a gas flow path connected to an electrode side where the generated water is generated, capable of storing water, and having a drainage mechanism for discharging the stored water. The fuel cell device according to claim 6. 8. The water removing means passes a high-temperature gas discharged from a predetermined high-temperature portion provided in a device including the fuel cell in a gas flow path connected to an electrode side on which the generated water is generated. 7. The fuel cell device according to claim 6, which is a gas introduction unit. 9. The fuel cell device according to claim 8, further comprising: a reformer for reforming a raw fuel made of hydrocarbon to generate the fuel, wherein the gas introducing means controls the inside of the gas flow path. The fuel cell device, wherein the high-temperature gas that passes is exhaust gas discharged from a heating device provided to raise the temperature of the inside of the reformer to a temperature range suitable for a reforming reaction. 10. The fuel according to claim 1, wherein the blocking prevention means is a retention prevention means for preventing generated water from condensing and remaining in a gas flow path connected to an electrode side on which the generated water is generated. Battery device. 11. The water retention means is provided in a gas flow path connected to an electrode side on which the generated water is generated, and is a water trapping means capable of trapping water while securing a space through which gas passes. The fuel cell device according to claim 1. 12. The fuel cell according to claim 11, wherein the water trapping means has a mesh structure provided on an inner wall surface of a gas flow path connected to an electrode on which the generated water is generated. 13. The fuel cell device according to claim 1, wherein the electrode side on which the generated water is generated is a cathode side. 14. A flow channel freezing prevention method for a fuel cell device, wherein a fuel generated by using an alcohol-based hydrocarbon as a raw fuel and an oxidizing gas containing oxygen are supplied to obtain an electromotive force by an electrochemical reaction. A method for preventing freezing of a flow channel of a fuel cell device that supplies the raw fuel to a gas flow channel connected to an electrode side on which water generated by the electrochemical reaction is generated. 15. A method for preventing freezing of a flow channel of a fuel cell device, wherein a fuel is supplied to an anode side and an oxidizing gas containing oxygen is supplied to a cathode side to obtain an electromotive force by an electrochemical reaction. A fuel cell device that stores condensed water generated in a gas flow path connected to an electrode side on which water generated by the electrochemical reaction is generated, and discharges the stored condensed water when the operation of the fuel cell device is stopped. Channel freezing prevention method. 16. A method for preventing freezing of a flow channel of a fuel cell device, wherein a fuel is supplied to an anode side and an oxidizing gas containing oxygen is supplied to a cathode side to obtain an electromotive force by an electrochemical reaction. In a gas flow path connected to an electrode side on which water generated by the electrochemical reaction is generated, a flow of a fuel cell device through which a high-temperature gas discharged from a predetermined high-temperature portion provided in the device including the fuel cell passes. Road freezing prevention method.