JP2007323849A - Fuel cell power generation system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell power generation system capable of easily stopping the operation of a fuel reformer and surely preventing deterioration of a catalyst in the fuel reformer. <P>SOLUTION: Fuel necessary for power generation in a fuel cell 1 is supplied from the fuel reformer 7. Chemical reaction converting raw materials into fuel is performed in the fuel reformer 7. An automatic water supply device 14 for supplying water to the fuel reformer 7 when the operation of the fuel reformer 7 is stopped is connected to the fuel reformer 7. The automatic water supply device 14 has a water tank 15 storing water and a water suction pipe 16 connected to the fuel reformer 7 and sealed with water in the water tank 15. When the operation of the fuel reformer 7 is stopped, penetration of outside air into the fuel reformer 7 is prevented with a fuel pipe shutoff valve 13. After that, water in the water tank 15 is sucked into the fuel reformer 7 through the water suction pipe 16 by drop in pressure inside the fuel reformer 7. Sucked water is converted into steam in the fuel reformer 7. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a fuel cell power generation system having a fuel reformer that supplies fuel to a fuel cell.

  Normally, when the fuel reformer is in operation, the chemical reaction takes place in the fuel reformer, so the temperature of the fuel reformer is high. When the operation of the fuel reformer is stopped in a high temperature state, for example, outside air or the like is introduced into the fuel reformer due to a decrease in pressure in the fuel reformer. When outside air is introduced into the high-temperature fuel reformer, the catalyst in the fuel reformer reacts with oxygen in the outside air to promote deterioration of the catalyst.

  Conventionally, in order to prevent the deterioration of the catalyst in the fuel reformer, there is a method for stopping a polymer electrolyte fuel cell that supplies water vapor into the fuel reformer when the operation of the fuel reformer is stopped. Proposed. In this conventional method for stopping a polymer electrolyte fuel cell, after the supply of water vapor into the fuel reformer, when the temperature of the fuel reformer falls below a predetermined temperature, air is introduced into the fuel reformer. Supplied to. Thereby, when the temperature of the fuel reformer is high, the introduction of air into the fuel reformer is prevented by the water vapor, and the oxidation of the catalyst is prevented (see Patent Document 1).

JP 2002-8701 A

  However, in the method for stopping a polymer electrolyte fuel cell disclosed in Patent Document 1, the supply of water vapor must be continued even after the operation of the fuel reformer is stopped. Further, control for switching the gas supplied into the fuel reformer from water vapor to air is also necessary. Therefore, it takes time to stop the operation of the fuel reformer.

  In addition, when the operation of the fuel reformer is stopped due to a power failure or the like, it is impossible to control the continuation of steam supply or switching from steam to air, and the catalyst in the fuel reformer cannot be controlled. Deterioration is accelerated and the performance of the fuel reformer is reduced.

  The present invention has been made to solve the above-described problems, and can easily stop the operation of the fuel reformer and more reliably suppress the deterioration of the performance of the fuel reformer. An object of the present invention is to obtain a fuel cell power generation system that can be realized.

  A fuel cell power generation system according to the present invention includes a fuel cell that generates power by receiving supply of fuel and an oxidant, a fuel reformer that converts a raw material into fuel by a chemical reaction, and a water suction pipe connected to the fuel reformer And an automatic water supply device in which the water suction pipe is sealed with water, and a shutoff valve for preventing the entry of outside air into the fuel reformer when the operation of the fuel reformer is stopped. When the operation of the reformer is stopped, due to a decrease in the pressure in the fuel reformer, water from the automatic water supply device is sucked into the fuel reformer through the water suction pipe and sucked into the fuel reformer. The water thus formed becomes steam in the fuel reformer.

  In the fuel cell power generation system according to the present invention, the water suction pipe connected to the fuel reformer is sealed with water, and outside air enters the fuel reformer when the operation of the fuel reformer is stopped. Since it is prevented by the shut-off valve, when the operation of the fuel reformer is stopped, water can be sucked into the fuel reformer due to a decrease in the pressure in the fuel reformer. Thereby, water vapor can be automatically generated in the fuel reformer, and the operation of the fuel reformer can be easily stopped. In addition, since the supply of water vapor into the fuel reformer is not stopped due to a failure of the control device or the like, it is possible to more reliably generate water vapor in the fuel reformer. Accordingly, it is possible to suppress the deterioration of the catalyst in the fuel reformer and to suppress the decrease in the performance of the fuel reformer more reliably.

Embodiment 1 FIG.
1 is a block diagram showing a fuel cell power generation system according to Embodiment 1 of the present invention. In the figure, a fuel cell 1 has a plurality of unit cells 2 stacked. Each unit cell 2 has an anode 3, a cathode 4, and a solid polymer electrolyte membrane 5 sandwiched between the anode 3 and the cathode 4. The fuel cell 1 generates power by receiving supply of fuel gas (fuel mainly composed of hydrogen) and air (oxidant). That is, the fuel cell 1 generates power by receiving supply of fuel gas to the anode 3 and supply of air to the cathode 4. Air is supplied to the fuel cell 1 by an air supply system 6.

  A fuel reformer 7 for generating fuel gas is connected to the fuel cell 1 via a fuel supply pipe 8. The fuel cell 1 and the fuel reformer 7 are communicated with each other by a fuel supply pipe 8. The fuel gas is supplied to the fuel cell 1 from the fuel reformer 7 through the fuel supply pipe 8.

  Each of the city gas and water is supplied to the fuel reformer 7 as a raw material. The city gas is supplied to the fuel reformer 7 by the city gas supply system 9, and the water is supplied to the fuel reformer 7 by the water supply system 10. The fuel reformer 7 converts the raw material received from each of the city gas supply system 9 and the water supply system 10 into fuel gas. In the fuel reformer 7, a plurality of chemical reactions are performed when the raw material is converted into fuel gas. The temperature conditions for each chemical reaction are different from each other.

  The fuel reformer 7 is filled with a plurality of types of catalysts 11 for performing each chemical reaction when the raw material is converted into fuel gas. The fuel reformer 7 is provided with a burner 12 that can adjust the temperature of each catalyst 11. The burner 12 is supplied with a combustible gas (combustion gas) for combustion. As the combustible gas supplied to the burner 12, for example, anode exhaust gas discharged from the anode 3 is used. This is because the anode exhaust gas contains residual hydrogen that could not be consumed by the battery reaction at the anode 3. In addition, in order to supplement a combustible component, city gas may be added to the anode exhaust gas.

  The temperature of each catalyst 11 during operation of the fuel reformer 7 is adjusted to a temperature according to the temperature condition of each chemical reaction by adjusting the combustion of the combustible gas by the burner 12. That is, the fuel reformer 7 is configured such that the temperature of each catalyst 11 is a temperature corresponding to the temperature condition of each chemical reaction. In this example, the following chemical reaction is performed in the fuel reformer 7.

  That is, in the fuel reformer 7, in order to convert methane, which is a main component of city gas from the city gas supply system 9, and water vapor obtained by vaporizing water from the water supply system 10 into fuel gas and carbon monoxide. The steam reforming reaction is performed. The steam reforming reaction is represented by the formula (1).

CH ₄ + H ₂ O → 3H ₂ + CO (1)

  For the steam reforming reaction, for example, a catalyst using nickel, ruthenium or the like as an active metal is used. Nickel, aluminum or the like as the active metal is dispersed and supported on a ceramic carrier such as alumina. Further, the temperature of the steam reforming reaction is set to a maximum of 700 ° C., for example.

  Since the fuel cell 1 has a strong poisoning tendency with respect to carbon monoxide in the fuel gas, for example, it is necessary to reduce the concentration of carbon monoxide in the fuel gas to 10 ppm or less. Therefore, in the fuel reformer 7, a shift reaction for reducing the carbon monoxide generated by the steam reforming reaction is also performed. The shift reaction is represented by formula (2).

CO + H ₂ O → H ₂ + CO ₂ (2)

  For the shift reaction, for example, a catalyst using copper or the like as an active metal is used. Copper as an active metal is dispersed and supported on a carrier such as zinc oxide or alumina. Further, the temperature of the shift reaction is set to 200 ° C., for example.

  In the shift reaction, for example, the carbon monoxide can be reduced only to 0.5 vol% (dry gas standard), and the concentration of carbon monoxide in the fuel gas cannot be reduced to a target of 10 ppm or less. Therefore, in the fuel reformer 7, a CO oxidation reaction for further reducing the concentration of carbon monoxide in the fuel gas is also performed. Thereby, the concentration of carbon monoxide in the fuel gas is set to 10 ppm or less. The CO oxidation reaction is a reaction for selectively burning carbon monoxide, and is represented by the formula (3).

CO + (1/2) O ₂ → CO ₂ (3)

  For the CO oxidation reaction, for example, a catalyst using platinum, ruthenium or the like as an active metal is used. Platinum, ruthenium, and the like as active metals are dispersed and supported on a carrier such as alumina. The temperature of the CO oxidation reaction is set to 150 ° C., for example.

  When the operation of the fuel reformer 7 is stopped, the supply of raw materials from the city gas supply system 9 and the water supply system 10 and the combustion of the burner 12 are stopped. When the operation of the fuel reformer 7 is stopped, the temperature of the fuel reformer 7 decreases due to heat dissipation or the like, and the volume of gas in the fuel reformer 7 contracts. When the inside of the fuel reformer 7 is not sealed, outside air enters the fuel reformer 7.

  Therefore, the fuel supply pipe 8 is provided with a fuel pipe cutoff valve 13 for preventing the outside air from entering the fuel reformer 7 when the operation of the fuel reformer 7 is stopped. The fuel pipe shut-off valve 13 can open and close the communication between the fuel cell 1 and the fuel reformer 7. The communication between the fuel cell 1 and the fuel reformer 7 is opened by the operation of the fuel pipe shut-off valve 13 when the fuel reformer 7 is being operated. When it is stopped, the fuel pipe shut-off valve 13 is closed by the operation.

  In this example, the fuel pipe cutoff valve 13 is an electromagnetic valve. Communication between the fuel cell 1 and the fuel reformer 7 is opened by supplying power to the fuel pipe shut-off valve 13 and closed when power supply to the fuel pipe shut-off valve 13 is stopped. In addition, when the supply of the raw material to the fuel reformer 7 is stopped, the entry of outside air from the city gas supply system 9 and the water supply system 10 into the fuel reformer 7 is also prevented. ing.

  Therefore, when the operation of the fuel reformer 7 is stopped, the volume of the gas in the fuel reformer 7 is contracted, so that the pressure in the fuel reformer 7 is reduced to a negative pressure below atmospheric pressure. It will be.

  Connected to the fuel reformer 7 is an automatic water supply device 14 that supplies water for generating water vapor in the fuel reformer 7 into the fuel reformer 7 when the fuel reformer 7 is stopped. . The automatic water supply device 14 supplies a predetermined amount of water into the fuel reformer 7 and then supplies outside air into the fuel reformer 7. The supply of water and outside air from the automatic water supply device 14 into the fuel reformer 7 is performed by suction into the fuel reformer 7 due to a decrease in the pressure in the fuel reformer 7.

  When water is sucked into the high temperature fuel reformer 7, steam is generated in the fuel reformer 7. Thereby, the pressure in the fuel reformer 7 is maintained, and the entry of outside air into the fuel reformer 7 is prevented. The amount of water sucked into the fuel reformer 7 (predetermined amount) is until the temperature in the fuel reformer 7 is equal to or lower than a predetermined temperature (for example, 200 ° C.) at which the oxidation reaction of the catalyst 11 can be suppressed. It is set based on the amount of water vapor that maintains the pressure in the fuel reformer 7. That is, the amount of water sucked into the fuel reformer 7 so that the pressure maintained by the steam in the fuel reformer 7 is continued until the temperature in the fuel reformer 7 becomes a predetermined temperature or lower. Is decided.

  The automatic water supply apparatus 14 includes a water tank 15 that stores water to be sucked into the fuel reformer 7 and a water suction pipe 16 that guides the water in the water tank 15 into the fuel reformer 7. .

  One end of the water suction pipe 16 is connected to the fuel reformer 7, and the other end (tip) of the water suction pipe 16 is inserted into the water in the water tank 15. Thereby, the inside of the tip of the water suction pipe 16 is filled with water in the water tank 15. That is, the water suction pipe 16 is sealed with water in the water tank 15.

  When the operation of the fuel reformer 7 is stopped, a predetermined amount of water passes from the water tank 15 through the water suction pipe 16 into the fuel reformer 7 due to a decrease in the pressure in the fuel reformer 7. Sucked. The amount of water stored in the water tank 15 is adjusted so that the amount of water sucked into the fuel reformer 7 becomes a predetermined amount. The amount of water in the water tank 15 is adjusted, for example, by detecting the water level with a water level sensor.

  In addition, an open pipe 17 that is open to the outside air is provided at the top of the water tank 15. That is, the water tank 15 is open to the outside air (air). As a result, a predetermined amount of water is sucked into the fuel reformer 7, and after the temperature in the fuel reformer 7 becomes lower than the predetermined temperature, the pressure in the fuel reformer 7 further decreases. Thus, outside air is sucked from the water tank 15 into the fuel reformer 7 through the water suction pipe 16.

  The water suction pipe 16 is provided with a suction pipe cutoff valve 18 for preventing water from entering the fuel reformer 7 from the water tank 15 when the fuel reformer 7 is operating. ing. The suction pipe shut-off valve 18 closes the communication in the water suction pipe 16 when the fuel reformer 7 is being operated, and is in the water suction pipe 16 when the operation of the fuel reformer 7 is stopped. Open communication. In this example, the suction pipe cutoff valve 18 is an electromagnetic valve. The communication in the water suction pipe 16 is closed by supplying power to the suction pipe cutoff valve 18 and opened by stopping the power supply to the suction pipe cutoff valve 18.

  Next, the operation will be described. When the fuel cell power generation system is in operation, power supply to each of the fuel pipe cutoff valve 13 and the suction pipe cutoff valve 18 is continued. Thereby, the communication in the fuel supply pipe 8 is opened by the fuel pipe cutoff valve 13, and the communication in the water suction pipe 16 is closed by the suction pipe cutoff valve 18. When raw materials are supplied from the city gas supply system 9 and the water supply system 10 into the fuel reformer 7, a plurality of chemical reactions are performed in the fuel reformer 7, and the raw materials are converted into fuel gas. . Thereafter, the generated fuel gas is sent from the fuel reformer 7 to the anode 3 of the fuel cell 1.

  On the other hand, air is sent from the air supply system 6 to the cathode 4 of the fuel cell 1. At this time, the air from the air supply system 6 is humidified by a humidifier or the like.

  When the fuel cell 1 is supplied with fuel and air, power generation is performed in the fuel cell 1. Thereafter, the anode exhaust gas discharged from the anode 3 is sent to the burner 12 as a combustion gas. The anode exhaust gas sent to the burner 12 is burned for adjusting the temperature in the fuel reformer 7 and discharged into the atmosphere.

  When the operation of the fuel cell power generation system is stopped, supply of raw materials from the city gas supply system 9 and the water supply system 10 to the fuel reformer 7, supply of air from the air supply system 6 to the fuel cell 1, And combustion of the burner 12 is stopped. At this time, the power supply to each of the fuel pipe cutoff valve 13 and the suction pipe cutoff valve 18 is also stopped. Thereby, the communication in the fuel supply pipe 8 is closed by the fuel pipe cutoff valve 13, and the communication in the water suction pipe 16 is opened by the suction pipe cutoff valve 18.

  Thereafter, when the temperature in the fuel reformer 7 decreases and the pressure in the fuel reformer 7 decreases, the water filled in the water suction pipe 16 is sucked into the fuel reformer 7. Thereby, the water stored in the water tank 15 is automatically supplied into the fuel reformer 7 through the water suction pipe 16. At this time, the water level stored in the water tank 15 is continuously lowered with the supply of water into the fuel reformer 7.

  Thereafter, in the fuel reformer 7, the supplied water is vaporized to generate water vapor. Thereby, the pressure in the fuel reformer 7 is maintained, and the entry of outside air into the fuel reformer 7 is prevented. In addition, the temperature in the fuel reformer 7 also decreases continuously.

  Thereafter, when the amount of water supplied into the fuel reformer 7 reaches a predetermined amount, the water level stored in the water tank 15 is lower than the height of the opening at the tip of the water suction pipe 16. Thereby, the supply of water into the fuel reformer 7 is stopped, and the outside air (air) taken into the water tank 15 through the open pipe 17 passes through the water suction pipe 16 and enters the fuel reformer 7. Will continue to be aspirated.

  At this time, the supply of a predetermined amount of water into the fuel reformer 7 causes the temperature in the fuel reformer 7 to be equal to or lower than the predetermined temperature, so that outside air is supplied into the fuel reformer 7. However, the oxidation of the catalyst is suppressed, and the promotion of the deterioration of the catalyst is suppressed. In this way, the operation of the fuel reformer 7 is stopped, and the operation of the fuel cell power generation system is stopped.

  Further, when restarting the operation of the fuel cell power generation system, the inside of the fuel reformer 7 is heated by the combustion of the burner 12, and the temperature inside the fuel reformer 7 reaches a temperature suitable for the operation of the fuel reformer 7. To raise. At this time, when the temperature in the fuel reformer 7 reaches a predetermined temperature, the deterioration of the catalyst is promoted by the air remaining in the fuel reformer 7. Steam is supplied into the reformer 7 to replace the air in the fuel reformer 7 with steam.

  In such a fuel cell power generation system, the water suction pipe 16 connected to the fuel reformer 7 is sealed with water, and the outside air into the fuel reformer 7 when the operation of the fuel reformer 7 is stopped. Is prevented by the fuel pipe shut-off valve 13, so that when the operation of the fuel reformer 7 is stopped, the water in the fuel reformer 7 is reduced due to a decrease in the pressure in the fuel reformer 7. Can be aspirated. That is, after the operation of the fuel reformer 7 is stopped, water for generating water vapor can be automatically supplied into the fuel reformer 7. Therefore, it is not necessary to perform conventional control for continuing the supply of water vapor into the fuel reformer 7 when the operation of the fuel reformer 7 is stopped, and the operation of the fuel reformer 7 can be easily stopped. Further, since the supply of water vapor into the fuel reformer 7 is not stopped due to a failure of the control device or the like, water vapor can be generated in the fuel reformer 7 more reliably. Accordingly, it is possible to suppress the deterioration of the catalyst in the fuel reformer 7 and to suppress the decrease in the performance of the fuel reformer more reliably.

  Further, since the amount of water sucked into the fuel reformer 7 is a predetermined amount set in advance, for example, the fuel reformer by supplying a large amount of water into the fuel reformer 7 7 can be prevented from lowering the function.

  Moreover, since the water suction pipe 16 is sealed with water by inserting the tip of the water suction pipe 16 into the water in the water tank 15, by adjusting the amount of water in the water tank 15, The amount of water sucked into the fuel reformer 7 can be adjusted. Therefore, the amount of water sucked into the fuel reformer 7 can be easily adjusted.

  Further, the predetermined amount of water sucked into the fuel reformer 7 is based on the amount of water vapor that maintains the pressure in the fuel reformer 7 until the temperature in the fuel reformer 7 becomes equal to or lower than the predetermined temperature. Therefore, when the supply of water into the fuel reformer 7 is completed, the temperature in the fuel reformer 7 can be set to a predetermined temperature or lower. Thereby, even when outside air enters the fuel reformer 7 after supplying water, the oxidation reaction of the catalyst 11 is suppressed, and the promotion of deterioration of the catalyst 11 can be suppressed.

  In addition, since the water tank 15 is open to the outside air and a predetermined amount of water is sucked into the fuel reformer 7, the outside air is sucked into the fuel reformer 7. Control for normally stopping the operation can be automatically performed, and the promotion of deterioration of the catalyst 11 can be more reliably suppressed.

  In the above example, when each of the city gas supply system 9 and the water supply system 10 stops supplying the raw material into the fuel reformer 7, the outside air enters the fuel reformer 7. However, when there is a possibility that outside air may enter the fuel reformer 7 from at least one of the city gas supply system 9 and the water supply system 10, the city gas supply system 9 and Between each of the water supply systems 10 and the fuel reformer 7, a shut-off valve for preventing the entry of outside air into the fuel reformer 7 may be provided. In this case, when the operation of the fuel reformer 7 is being performed, the shut-off valve is opened so that the raw material can be supplied into the fuel reformer 7, and when the operation of the fuel reformer 7 is stopped, The supply of the raw material into the fuel reformer 7 is shut off by the shut-off valve

  In the above example, the fuel pipe shutoff valve 13 is provided in the fuel supply pipe 8 in order to prevent the outside air from entering the fuel reformer 7. The position where the shutoff valve is provided is not limited to the fuel supply pipe 8 as long as the entry of the fuel can be prevented. For example, a shutoff valve may be provided in the anode side exhaust pipe that guides the anode exhaust gas discharged from the anode 3.

  Further, in the above example, water to be sucked into the fuel reformer 7 is stored in the water tank 15, but if a predetermined amount of water can be stored in the water suction pipe 16, The water tank 15 may not be provided.

Embodiment 2. FIG.
FIG. 2 is a block diagram showing a fuel cell power generation system according to Embodiment 2 of the present invention. In the figure, the water tank 15 is supplied with a supplementary gas for sucking into the fuel reformer 7 after a predetermined amount of water has been sucked into the fuel reformer 7. In this example, city gas is used as supplementary gas.

  Here, when the city gas is supplied into the fuel reformer 7 as a supplementary gas, if the temperature of the catalyst 11 in the fuel reformer 7 is high, higher-order hydrocarbon components ( Carbon may be generated by thermal decomposition of ethane, propane or the like, and the fuel reformer 7 may be blocked. Therefore, it is necessary to supply the city gas into the fuel reformer 7 after the temperature in the fuel reformer 7 has dropped to a predetermined temperature (for example, 300 ° C.) or less that can suppress the generation of carbon.

  From this, the amount (predetermined amount) of water stored in the water tank 15 is within the fuel reformer 7 until the temperature in the fuel reformer 7 falls below a predetermined temperature at which carbon generation can be suppressed. It is set based on the amount of water vapor that maintains the pressure. Thereby, the supply of the supplementary gas into the fuel reformer 7 is stopped until the temperature in the fuel reformer 7 becomes a predetermined temperature or lower.

  The supplementary gas is stored in a gas storage device 21 that communicates with the water tank 15. The gas storage device 21 communicates with the water tank 15 via the gas supply pipe 22. The gas supply pipe 22 is connected to the upper part of the water tank 15. The water tank 15, the gas supply pipe 22, and the gas storage device 21 are hermetically sealed so that outside air can be prevented from entering.

  The gas storage device 21 is a deformable flexible container that contains a supplementary gas. The flexible container is composed of, for example, a laminated film having a multilayer structure made of an aluminum foil and a polymer film. Other configurations are the same as those in the first embodiment.

  Next, the operation will be described. The operation when the fuel cell power generation system is operating is the same as that of the first embodiment.

  When the operation of the fuel cell power generation system is stopped, a predetermined amount of water is sucked from the water tank 15 into the fuel reformer 7 through the water suction pipe 16 by the same operation as in the first embodiment. Thereby, the temperature in the fuel reformer 7 is lowered to a predetermined temperature (for example, 300 ° C.) or lower.

  Thereafter, when the water level stored in the water tank 15 falls below the height of the opening at the tip of the water suction pipe 16, the supply of water into the fuel reformer 7 is stopped, and the gas storage device 21. The supplementary gas (city gas) supplied from the water into the water tank 15 is continuously sucked into the fuel reformer 7 through the water suction pipe 16. Thereby, a flexible container deform | transforms and the fluctuation | variation of the pressure in the fuel reformer 7 and the water tank 15 is absorbed. The subsequent operation is the same as in the first embodiment.

  In such a fuel cell power generation system, a supplementary gas to be sucked into the fuel reformer 7 is supplied into the water tank 15, and after a predetermined amount of water is sucked into the fuel reformer 7, Since the supplementary gas is sucked from the water tank 15 into the fuel reformer 7, after supplying a predetermined amount of water into the fuel reformer 7, a gas different from the outside air is supplied to the fuel reformer. 7 can be automatically fed into. Thereby, even if it is temperature higher than the case where external air is supplied, supply of the gas into the fuel reformer 7 can be started, and the function fall of the fuel reformer 7 can further be suppressed. .

  In addition, the gas storage device 21 communicating with the water tank 15 stores the supplementary gas, and the pressure fluctuation in the water tank 15 is absorbed by the gas storage device 21, so that the supplementary gas is fuel reformed. Even when it is sucked into the vessel 7, it is possible to prevent a sudden drop in pressure in the water tank 15 and the fuel reformer 7.

  In the above example, in order to absorb the pressure fluctuation in the water tank 15 and the fuel reformer 7, the gas storage device 21 is a flexible container that can be deformed. The structure of the gas storage device 21 may be, for example, a piston structure or a bellows structure. Even in this case, pressure fluctuations in the water tank 15 and the fuel reformer 7 can be absorbed.

  In the above example, the supplementary gas to be sucked into the fuel reformer 7 is city gas. For example, combustion exhaust gas generated by combustion in the burner 12 or oxygen-containing gas such as air containing oxygen. Alternatively, a nitrogen-based deoxygenated gas or the like that has been subjected to deoxygenation treatment may be used as a supplementary gas. In this way, since a gas with a low oxygen content can be supplied into the fuel reformer 7, it is possible to further suppress the deterioration of the catalyst 11. Further, when the combustion exhaust gas is used as a supplementary gas, the gas generated during operation of the fuel reformer 7 can be used effectively.

BRIEF DESCRIPTION OF THE DRAWINGS It is a block diagram which shows the fuel cell power generation system by Embodiment 1 of this invention. It is a block diagram which shows the fuel cell power generation system by Embodiment 2 of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Fuel cell, 7 Fuel reformer, 13 Fuel pipe shutoff valve (shutoff valve), 14 Automatic water supply apparatus, 15 Water tank, 16 Water suction pipe, 21 Gas storage apparatus.

Claims (8)

A fuel cell that generates electricity by receiving supply of fuel and oxidant;
A fuel reformer that converts the raw material into the fuel by a chemical reaction;
An automatic water supply apparatus having a water suction pipe connected to the fuel reformer, the water suction pipe sealed with water, and into the fuel reformer when the operation of the fuel reformer is stopped; With a shut-off valve to prevent the outside air from entering,
When the operation of the fuel reformer is stopped, due to a decrease in the pressure in the fuel reformer, water from the automatic water feeder is sucked into the fuel reformer through the water suction pipe, and A fuel cell power generation system configured such that water sucked into a fuel reformer becomes steam in the fuel reformer.   2. The fuel cell power generation system according to claim 1, wherein the amount of water sucked into the fuel reformer is a predetermined amount set in advance.   The automatic water supply apparatus further includes a water tank for storing water to be sucked into the fuel reformer, and the water suction pipe is inserted by inserting a tip of the water suction pipe into the water in the water tank. The fuel cell power generation system according to claim 2, wherein the fuel cell is sealed with water.   3. The predetermined amount is set based on an amount of water vapor that maintains a pressure in the fuel reformer until a temperature in the fuel reformer becomes equal to or lower than a predetermined temperature. The fuel cell power generation system described in 1. The water tank is open to the outside air,
4. The fuel cell power generation system according to claim 3, wherein the outside air is sucked into the fuel reformer after the predetermined amount of water is sucked into the fuel reformer.   4. The supplementary gas for supplying the predetermined amount of water into the fuel reformer after the predetermined amount of water is sucked into the fuel reformer is supplied into the water tank. The fuel cell power generation system described. The supplementary gas is stored in a gas storage device communicating with the water tank,
The fuel cell power generation system according to claim 6, wherein the pressure fluctuation in the water tank is absorbed by the gas storage device.   The fuel cell power generation system according to claim 6, wherein the supplementary gas is a deoxygenated gas obtained by performing a deoxygenation process on an oxygen-containing gas containing oxygen.

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