JP2008192425A - Fuel cell system and its operation method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell system which can prevent formation of a puddle caused by condensation of water contained in steam and reformed gas or the like, and its operation method. <P>SOLUTION: In the fuel cell system 1 which is equipped with a reformer 2 for power generation in which reforming is carried out to form a reformed gas by reforming the reforming raw material for power generation, an SOFC stack 3 which is connected to the reformer 2 for power generation via a reformed gas supply tube 8 and which carries out power generation using the reformed gas obtained by the reformer 2 for power generation, and a reformer 4 for start-up and shutdown which forms the reformed gas by reforming the reforming raw material for start-up and shutdown in order to prevent oxidation degradation of the anode 3a of the SOFC stack 3, a combustion catalyst 15A is filled into the reformed gas supply tube 8, a combustion catalyst 15B is filled into a gas passage in the SOFC stack 3, and the fuel and air for catalytic combustion are supplied to the combustion catalysts 15A, 15B. By catalytic combustion heat of reaction at that time, the reformed gas supply tube 8 is kept hot at equal or more than the boiling point of water and at the temperature equal or less than the oxidation degradation temperature of the anode 3a. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a fuel cell system that generates power by introducing raw fuel and air, and an operation method thereof.

One type of fuel cell system is a solid oxide fuel cell (SOFC) system. In general, a solid oxide fuel cell system is obtained by reforming a hydrocarbon fuel (raw fuel) such as kerosene or city gas to produce a hydrogen-containing gas (reformed gas), and the reformer. A fuel cell stack that electrochemically generates and reacts the reformed gas and air. The fuel cell stack is usually operated at a high temperature of about 550 to 1000 ° C. As such an SOFC system, for example, one described in Patent Document 1 is known.
JP 2002-358997 A

  However, the following problems exist in the prior art. That is, when the reformed gas is circulated in a state where the temperature in the reformed gas flow path or the fuel cell stack is low when starting and stopping the fuel cell system, moisture contained in the reformed gas is condensed. For example, when a reforming material in which raw fuel and steam are mixed is supplied to the reformer, the steam condenses when steam is circulated in a state where the temperature of the steam channel or the reforming material channel is low. For this reason, a pool of water may occur in the reformed gas channel, the steam channel, and the like, and there is a possibility that a pulsating flow of the reformed gas and the channel blockage may occur. In addition, when the temperature inside the container that contains the fuel cell stack is low, moisture contained in the off-gas from the fuel cell stack may condense and a water pool may be formed inside the container. May leak. In addition, when the temperature inside the container is raised when the fuel cell system is started up, there is a possibility that damage to the fuel cell stack, piping, pumps, and other equipment due to bumping of the water pool, gas leakage from the container, water leakage, etc. is there.

  An object of the present invention is to provide a fuel cell system and a method for operating the same that can prevent the occurrence of a water pool due to condensation of moisture contained in water vapor, reformed gas, or the like.

  The fuel cell system of the present invention includes a reformer that reforms a raw fuel to generate a reformed gas, and a reformer that is connected to the reformer via a reformed gas flow path and is generated by the reformer. A fuel cell stack that generates power using gas, and a heating unit that heats at least one of a reformed gas channel, a gas channel in the fuel cell stack, and a downstream gas channel in the fuel cell stack. It is what.

  When such a fuel cell system of the present invention is started, when the reformed gas generated by the reformer is supplied to the fuel cell stack, the reforming gas flow path and the fuel cell stack in the fuel cell stack are supplied by the heating means. At least one of the gas flow path and the downstream gas flow path of the fuel cell stack is heated to a temperature equal to or higher than the boiling point of water, for example. In this case, when the reformed gas or the exhaust gas (off-gas) from the fuel cell stack passes, the condensation of moisture contained in these gases is suppressed, so that the generation of water pool due to the condensation of the moisture is prevented. Is done.

  When the fuel cell system of the present invention is stopped, the reformed gas flow path and the fuel cell stack are lowered to a predetermined temperature, and then the supply of the reformed gas to the fuel cell stack is stopped. Until the supply of the quality gas is stopped, at least one of the reformed gas flow path, the gas flow path in the fuel cell stack, and the downstream gas flow path of the fuel cell stack is maintained at a temperature equal to or higher than, for example, the boiling point of water. To do. Also in this case, when the reformed gas or the off-gas from the fuel cell stack passes, the condensation of moisture contained in these gases is suppressed, so that the occurrence of a water pool due to the condensation of the moisture is prevented.

  Preferably, the heating means includes a combustion catalyst provided in at least one of the reformed gas flow path, the gas flow path in the fuel cell stack, and the downstream gas flow path, and a means for supplying air to the combustion catalyst.

  By using the combustion catalyst as a heating means in this way, the heat source for a part of the equipment such as the reformed gas flow path, the gas flow path in the fuel cell stack, and the downstream gas flow path becomes extremely simple and space-saving. Can be achieved.

  The heating means may be a heater or a burner arranged in the vicinity of at least one of the reformed gas channel, the fuel cell stack, and the downstream gas channel.

  In this case, the reformed gas channel, the gas channel in the fuel cell stack, and the downstream gas channel can be heated without supplying the reformed gas or fuel generated by the reformer. Therefore, when starting the fuel cell system, before starting the supply of the reformed gas to the fuel cell stack, at least one of the reformed gas flow path, the gas flow path in the fuel cell stack, and the downstream gas flow path is set. The temperature can be surely raised to a temperature equal to or higher than the boiling point of water.

  Preferably, at least one of the reformed gas flow path, the gas flow path in the fuel cell stack, and the downstream gas flow path has a curved flow path portion formed to bend upward with respect to the direction of gravity acceleration. The heating means heats the region including the bent flow path portion.

  The bent flow path formed so as to bend upward with respect to the direction of gravitational acceleration is a portion where water pool is particularly likely to occur when moisture contained in the reformed gas or off-gas from the fuel cell stack is condensed. . Therefore, by heating a region including the bent flow path portion in the gas flow path, it is possible to effectively prevent a water pool from being generated due to condensation of water contained in the reformed gas or off gas.

  Further, preferably, the reformed gas flow path, the temperature detection means for detecting the temperature of at least one of the gas flow path in the fuel cell stack and the downstream gas flow path, and the reformed gas based on the detection signal of the temperature detection means The apparatus further includes control means for controlling the heating means so that at least one temperature of the flow path, the gas flow path in the fuel cell stack, and the downstream gas flow path is equal to or higher than the boiling point of water.

  By providing such temperature detection means and control means, when starting and stopping the fuel cell system, at least one temperature of the reformed gas flow path, the gas flow path in the fuel cell stack, and the downstream gas flow path is set. It can be automatically controlled so as to be equal to or higher than the boiling point of water.

  The fuel cell system of the present invention includes a reformer that reforms raw fuel to generate a reformed gas, a fuel cell stack that generates power using the reformed gas generated by the reformer, a fuel It is characterized by comprising a container for accommodating the battery stack and a heating means for heating at least the bottom of the container.

  When the fuel cell system of the present invention is started up, when supplying the reformed gas generated by the reformer to the fuel cell stack, at least the bottom of the container is heated above the boiling point of water by the heating means, for example. The temperature is raised to The bottom in the container is a place where water tends to accumulate when the moisture contained in the off gas from the fuel cell stack is condensed. In this case, by starting the supply of the reformed gas to the fuel cell stack, even if off-gas is discharged from the fuel cell stack, at least the bottom of the container has already been heated to a temperature above the boiling point of water. Yes. Therefore, the condensation of moisture contained in the off-gas is suppressed, so that the generation of a water pool due to the condensation of the moisture is prevented.

  Also, when stopping the fuel cell system of the present invention, after the temperature of the fuel cell stack is lowered to a predetermined temperature, the supply of the reformed gas to the fuel cell stack is stopped, but the supply of the reformed gas is stopped. Until then, the heating means holds at least the bottom of the container at a temperature equal to or higher than the boiling point of water, for example. In this case, since the condensation of moisture contained in the off gas from the fuel cell stack is suppressed, the occurrence of a water pool due to the condensation of the moisture is prevented.

  Furthermore, the fuel cell system of the present invention includes a reformer that reforms raw fuel to generate a reformed gas, a fuel cell stack that generates electric power using the reformed gas generated by the reformer, and a reformer. A steam channel for supplying steam to the mass device, a raw fuel channel for supplying raw fuel to the reformer, a steam channel and a raw fuel channel, A reforming material channel for introducing the reforming material mixed with steam into the reformer, and at least a steam channel or at least a reforming material stream among the steam channel, the raw fuel channel and the reforming material channel; And heating means for heating the path.

  When such a fuel cell system of the present invention is started up, when the raw fuel and steam are supplied to the reformer, the steam channel, the raw fuel channel and the reforming material channel are heated by the heating means. Of these, at least the steam channel or at least the reforming material channel is heated to a temperature equal to or higher than the boiling point of water, for example. In this case, for example, when only the steam is supplied before supplying the raw fuel, the condensation of the steam is suppressed, so that the generation of a water pool due to the condensation of the steam is prevented.

  In addition, when stopping the fuel cell system of the present invention, the supply of raw fuel and water vapor is stopped. Until the supply of the raw fuel and water vapor is stopped, the heating means stops the water vapor flow path, the raw fuel flow path. And at least the steam channel or at least the reforming material channel among the reforming material channels is maintained at a temperature equal to or higher than the boiling point of water, for example. In this case, for example, when only the water vapor is supplied after the supply of the raw fuel is stopped, the condensation of the water vapor is suppressed, so that the generation of a water pool due to the condensation of the water vapor is prevented.

  The present invention uses a reformer that reforms raw fuel to generate a reformed gas, and the reformer gas that is connected to the reformer via a reformed gas flow path and that is generated by the reformer. In a method of operating a fuel cell system including a fuel cell stack that generates power, when starting the fuel cell system, a reformed gas flow path, a gas flow path in the fuel cell stack, a downstream gas flow path of the fuel cell stack, At least one is heated to a temperature equal to or higher than the boiling point of water, and the reformed gas is supplied to the fuel cell stack in that state.

  In such an operation method of the fuel cell system of the present invention, when the supply of the reformed gas to the fuel cell stack is started, the reformed gas channel, the gas channel in the fuel cell stack, and the downstream gas channel At least one of these has already been heated to a temperature above the boiling point of water. For this reason, when the reformed gas or the off-gas from the fuel cell stack passes, condensation of moisture contained in the reformed gas or the like is suppressed, so that generation of a water pool due to condensation of the moisture is prevented.

  The present invention also provides a reformer for reforming raw fuel to generate a reformed gas, a reformer connected to the reformer via a reformed gas flow path, and the reformed gas generated by the reformer. In a method of operating a fuel cell system including a fuel cell stack that generates electric power using a combustion catalyst, at least one of a reformed gas channel, a gas channel in the fuel cell stack, and a downstream gas channel in the fuel cell stack When the fuel cell system is started up by filling in advance, the reformed gas is supplied to the fuel cell stack and air is supplied to the combustion catalyst, and the reformed gas channel, the gas channel in the fuel cell stack, It is characterized in that at least one of the downstream gas passages is maintained at a temperature higher than the boiling point of water.

  In such an operation method of the fuel cell system of the present invention, when supply of the reformed gas to the fuel cell stack is started, air is supplied to the combustion catalyst so that the reformed gas flow path, the fuel cell stack inside At least one of the gas channel and the downstream gas channel is heated to a temperature equal to or higher than the boiling point of water. For this reason, when the reformed gas or the off-gas from the fuel cell stack passes, the condensation of moisture contained in these gases is suppressed, so that the generation of a water pool due to the condensation of the moisture is prevented.

  The present invention also provides a reformer for reforming raw fuel to generate a reformed gas, a reformer connected to the reformer via a reformed gas flow path, and the reformed gas generated by the reformer. In a method of operating a fuel cell system including a fuel cell stack that generates electricity using the reformed gas flow path, a gas flow path in the fuel cell stack, and a downstream gas flow in the fuel cell stack when the fuel cell system is stopped The temperature is lowered so that at least one of the paths is maintained at a temperature equal to or higher than the boiling point of water, and the supply of the reformed gas to the fuel cell stack is stopped in this state.

  In such an operation method of the fuel cell system of the present invention, until the supply of the reformed gas to the fuel cell stack is stopped, the reformed gas channel, the gas channel in the fuel cell stack, and the downstream gas channel At least one of these is maintained at a temperature above the boiling point of water. For this reason, when the reformed gas or the off-gas from the fuel cell stack passes, the condensation of moisture contained in these gases is suppressed, so that the generation of a water pool due to the condensation of the moisture is prevented.

  The present invention further includes a reformer that reforms raw fuel to generate reformed gas, a fuel cell stack that generates power using the reformed gas generated by the reformer, and a fuel cell stack. When operating the fuel cell system, the temperature of at least the bottom of the container is raised to a temperature equal to or higher than the boiling point of water, and the reformed gas is fed to the fuel cell stack in that state. It is characterized by supplying.

  In such an operation method of the fuel cell system of the present invention, when supply of the reformed gas to the fuel cell stack is started, at least the bottom of the container has already been heated to a temperature equal to or higher than the boiling point of water. . For this reason, the condensation of moisture contained in the off-gas from the fuel cell stack is suppressed, so that the generation of a water pool due to the condensation of the moisture is prevented.

  The present invention also includes a reformer that reforms a raw fuel to generate a reformed gas, a fuel cell stack that generates power using the reformed gas generated by the reformer, and a fuel cell stack. When stopping the fuel cell system, the temperature is lowered so as to maintain at least the bottom of the container at a temperature equal to or higher than the boiling point of water, and in that state, the fuel cell system is supplied to the fuel cell stack. The supply of the reformed gas is stopped.

  In such an operation method of the fuel cell system of the present invention, at least the bottom of the container is maintained at a temperature equal to or higher than the boiling point of water until the supply of the reformed gas to the fuel cell stack is stopped. For this reason, the condensation of moisture contained in the off-gas from the fuel cell stack is suppressed, so that the generation of a water pool due to the condensation of the moisture is prevented.

  Furthermore, the present invention is directed to a reformer that reforms raw fuel to generate a reformed gas, a fuel cell stack that generates power using the reformed gas generated by the reformer, and a reformer. A steam channel for supplying steam, a raw fuel channel for supplying raw fuel to the reformer, a steam channel and a raw fuel channel, and the raw fuel and steam are mixed. In a method of operating a fuel cell system comprising a reformed material channel for introducing the reformed material into the reformer, when the fuel cell system is started, a steam channel, a raw fuel channel, and a reformed material Among the channels, at least the steam channel is heated to a temperature equal to or higher than the boiling point of water, and in this state, steam and raw fuel are sequentially supplied to the reformer.

  In such an operation method of the fuel cell system of the present invention, when the supply of steam and raw fuel to the reformer is sequentially started, the steam flow path, raw fuel flow path, and reforming raw material flow path are Of these, at least the steam channel has already been heated to a temperature equal to or higher than the boiling point of water. For this reason, when supplying only water vapor | steam before supplying raw fuel, since water vapor | steam condensation is suppressed, generation | occurrence | production of the water pool by water vapor | steam condensation is prevented.

  Further, the present invention is directed to a reformer that reforms raw fuel to generate a reformed gas, a fuel cell stack that generates power using the reformed gas generated by the reformer, and a reformer. A steam channel for supplying steam, a raw fuel channel for supplying raw fuel to the reformer, a steam channel and a raw fuel channel, and the raw fuel and steam are mixed. In a method of operating a fuel cell system comprising a reformed material channel for introducing the reformed material into a reformer, when the fuel cell system is stopped, a steam channel, a raw fuel channel, and a reformed material Among the channels, at least the water vapor channel is maintained at a temperature equal to or higher than the boiling point of water, and the supply of the raw fuel and the water vapor is sequentially stopped in this state.

  In such an operation method of the fuel cell system of the present invention, until the supply of the raw fuel and the steam toward the reformer is sequentially stopped, the steam flow path, the raw fuel flow path, and the reforming raw material flow path are stopped. Of these, at least the steam channel is maintained at a temperature equal to or higher than the boiling point of water. For this reason, since the condensation of water vapor is suppressed when only the water vapor is supplied after the supply of the raw fuel is stopped, the generation of a water pool due to the condensation of the water vapor is prevented.

  Furthermore, the present invention is directed to a reformer that reforms raw fuel to generate a reformed gas, a fuel cell stack that generates power using the reformed gas generated by the reformer, and a reformer. A steam channel for supplying steam, a raw fuel channel for supplying raw fuel to the reformer, a steam channel and a raw fuel channel, and the raw fuel and steam are mixed. In a method of operating a fuel cell system comprising a reformed material channel for introducing the reformed material into the reformer, when the fuel cell system is started, a steam channel, a raw fuel channel, and a reformed material The temperature of at least the reforming raw material flow path is raised to a temperature equal to or higher than the higher of the boiling points of water and raw fuel, and steam and raw fuel are sequentially supplied to the reformer in that state. It is a feature.

  In such an operation method of the fuel cell system of the present invention, when the supply of steam and raw fuel to the reformer is sequentially started, the steam flow path, raw fuel flow path, and reforming raw material flow path are Of these, at least the reforming raw material flow path is heated to a temperature equal to or higher than the higher of the boiling points of water and raw fuel. For this reason, when supplying only water vapor | steam before supplying raw fuel, since water vapor | steam condensation is suppressed, generation | occurrence | production of the water pool by water vapor | steam condensation is prevented. Further, when the raw fuel is supplied, the condensation of the raw fuel is also suppressed.

  Further, the present invention is directed to a reformer that reforms raw fuel to generate a reformed gas, a fuel cell stack that generates power using the reformed gas generated by the reformer, and a reformer. A steam channel for supplying steam, a raw fuel channel for supplying raw fuel to the reformer, a steam channel and a raw fuel channel, and the raw fuel and steam are mixed. In a method of operating a fuel cell system comprising a reformed material channel for introducing the reformed material into a reformer, when the fuel cell system is stopped, a steam channel, a raw fuel channel, and a reformed material It is characterized in that at least the reforming raw material flow path among the flow paths is maintained at a temperature equal to or higher than the higher one of the boiling points of water and raw fuel, and the supply of raw fuel and water vapor is sequentially stopped in that state. is there.

  In such an operation method of the fuel cell system of the present invention, until the supply of the raw fuel and the steam toward the reformer is sequentially stopped, the steam flow path, the raw fuel flow path, and the reforming raw material flow path are stopped. Of these, at least the reforming raw material flow path is maintained at a temperature equal to or higher than the higher of the boiling points of water and raw fuel. For this reason, since the condensation of water vapor is suppressed when only the water vapor is supplied after the supply of the raw fuel is stopped, the generation of a water pool due to the condensation of the water vapor is prevented. Further, when the raw fuel is supplied, the condensation of the raw fuel is also suppressed.

  According to the present invention, it is possible to prevent the occurrence of a water pool due to condensation of moisture contained in water vapor, reformed gas, or the like. This prevents problems such as pulsation of gas in the gas flow path, blockage of the gas flow path, breakage of fuel cell stack, piping and pumps due to bumping of the water pool, occurrence of water leakage from inside the container, It becomes possible to improve the reliability of the system.

  DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of a fuel cell system and an operation method thereof according to the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a system configuration diagram showing a first embodiment of a fuel cell system according to the present invention. In the figure, a fuel cell system 1 of the present embodiment includes a power reformer 2 that reforms raw fuel to generate a reformed gas, and a reformed gas obtained by the power reformer 2. A solid oxide fuel cell (SOFC) stack 3 that generates power using air, and a start / stop reformer 4 that reforms raw fuel to generate reformed gas are provided. The power reformer 2, the SOFC stack 3, and the start / stop reformer 4 are housed in a module container 5 and modularized.

  A power supply reformer 2 is connected to a raw material introduction pipe 6 that forms a reformed raw material flow path for introducing a power generation reformed raw material mixed with raw fuel and steam from the outside of the module container 5. . The raw material introduction pipe 6 is supplied with a fuel supply pipe 70 that forms a raw fuel flow path for supplying liquid raw fuel to the power reformer 2, and steam is supplied to the power reformer 2. Is connected to a water vapor supply pipe 71 that forms a water vapor flow path. As the raw fuel, for example, a hydrocarbon fuel such as kerosene or city gas is used. A water supply pipe 72 for supplying liquid water is connected to the water vapor supply pipe 71 via a water vaporizer 73. The fuel supply pipe 70 is provided with an electromagnetic valve 74 that adjusts the supply amount of raw fuel, and the water supply pipe 72 is provided with an electromagnetic valve 75 that adjusts the supply amount of water. Further, a fuel vaporizer 76 is provided in the raw material introduction pipe 6 outside the module container 5.

  The water vaporizer 73 vaporizes (evaporates) the liquid water sent through the water supply pipe 72 to generate water vapor. On the other hand, the fuel vaporizer 76 vaporizes (evaporates) the raw fuel sent through the fuel supply pipe 70 to generate the raw fuel gas and mix it with the water vapor obtained by the water vaporizer 73. In this manner, a gaseous reforming raw material for power generation is generated. At this time, it is desirable to supply the fuel vaporizer 76 with water vapor at a temperature that does not condense due to the vaporization heat of the raw fuel.

  The fuel vaporizer 76 vaporizes (evaporates) the liquid raw fuel, mixes it with water vapor, and generates a reforming raw material gas for power generation. Then, the power generation reforming raw material gas is introduced into the power generation reformer 2. The water vaporizer 73 and the fuel vaporizer 76 may be in the module container 5.

  The power generation reformer 2 generates a reformed gas containing hydrogen and carbon monoxide by causing the reforming raw material for power generation to undergo a steam reforming reaction with a reforming catalyst. The steam reforming reaction is a very large endothermic reaction, and since the reaction temperature is relatively high at about 550 to 750 ° C., a high-temperature heat source is required. For this reason, the power reformer 2 is disposed in the vicinity of the SOFC stack 3 and performs a steam reforming reaction using radiant heat from the SOFC stack 3 and off-gas combustion heat.

  The SOFC stack 3 is connected to the power reformer 2 via a reformed gas supply pipe 8 that forms a reformed gas flow path. The SOFC stack 3 includes an air introduction pipe 9 for introducing power generation air from the outside of the module container 5, and a gas exhaust pipe 10 that forms a downstream gas flow path for exhausting off-gas from the SOFC stack 3. And are connected. The air introduction pipe 9 is provided with an electromagnetic valve 11 that adjusts the amount of power generation air introduced.

  The SOFC stack 3 is configured by stacking a plurality of battery cells. The battery cell includes an anode (fuel electrode) 3a, a cathode (air electrode) 3b, an electrolyte 3c disposed between the anode 3a and the cathode 3b, and a separator (externally disposed on the outside of the anode 3a and the cathode 3b). (Not shown). The reformed gas is introduced into the anode 3a, and power generation air is introduced into the cathode 3b. Thereby, an electrochemical power generation reaction is performed in each battery cell. The SOFC stack 3 normally operates at a high temperature of about 550 to 1000 ° C.

  The starting / stopping reformer 4 has a raw material introduction pipe 12 that forms a reforming raw material flow path for introducing the starting / stopping reforming raw material mixed with raw fuel and steam from the outside of the module container 5. It is connected. The raw material introduction pipe 12 includes a fuel supply pipe 80 that forms a raw fuel flow path for supplying liquid raw fuel to the start / stop reformer 4, and steam start / stop reformer 4. Is connected to a water vapor supply pipe 81 that forms a water vapor channel for supplying the water to the water. A water supply pipe 82 for supplying liquid water is connected to the water vapor supply pipe 81 via a water vaporizer 83. The fuel supply pipe 80 is provided with an electromagnetic valve 84 that adjusts the supply amount of raw fuel, and the water supply pipe 82 is provided with an electromagnetic valve 85 that adjusts the supply amount of water. Further, a fuel vaporizer 86 is provided in the raw material introduction pipe 12 outside the module container 5.

  As the raw fuel, for example, a hydrocarbon fuel such as kerosene or city gas is used in the same manner as the raw fuel supplied to the power reformer 2. This makes it possible to share the raw fuel for producing the reforming raw material for power generation and the supply source of the raw fuel for producing the starting / stopping reforming raw material.

  The water vaporizer 83 vaporizes (evaporates) the liquid water sent through the water supply pipe 82 to generate water vapor. On the other hand, the fuel vaporizer 86 vaporizes (evaporates) the raw fuel sent through the fuel supply pipe 80 to generate the raw fuel gas and mix it with the water vapor obtained by the water vaporizer 83. Thus, a gas starting / stopping reforming raw material is generated. At this time, it is desirable to supply the vaporizer 86 with water vapor at a temperature that does not condense due to the vaporization heat of the raw fuel.

  The fuel vaporizer 86 vaporizes (evaporates) the liquid raw fuel and mixes it with water vapor to generate a starting / stopping reforming raw material gas. Then, the starting / stopping reforming raw material gas is introduced into the starting / stopping reformer 4. The water vaporizer 83 and the fuel vaporizer 86 may be in the module container 5.

  The start / stop reformer 4 is a steam reforming reaction of the start / stop reforming material with a reforming catalyst in order to prevent oxidative deterioration of the anode 3a of the SOFC stack 3 when the fuel cell system 1 is started / stopped. Thus, a reformed gas containing hydrogen having reducibility is generated. The start / stop reformer 4 may have a smaller capacity than the power reformer 2 as long as the reformed gas can be obtained so as to protect the anode 3a from oxidative degradation.

  The start / stop reformer 4 is branched and connected to the raw material introduction pipe 6 via a reformed gas supply pipe 14 that forms a reformed gas flow path. The reformed gas generated by the start / stop reformer 4 is supplied to the SOFC stack 3 via the reformed gas supply pipe 14, the raw material introduction pipe 6, the power generation reformer 2 and the reformed gas supply pipe 8. Is done. Here, in order to reduce the reforming catalyst of the power reformer 2 by the reformed gas generated by the start / stop reformer 4, the reformed gas supply pipe 14 is connected to the power reformer 2. The reformed gas supply pipe 14 may be connected to the output side (reformed gas supply pipe 8) of the power reformer 2.

  The reformed gas supply pipe 8 is filled with a combustion catalyst 15A as a heating source. As shown in FIG. 2, the reformed gas supply pipe 8 has two bends that are bent upward (vertically upward or obliquely upward) from a direction perpendicular to the direction of gravitational acceleration (A direction in the figure), that is, from a horizontally extending portion. It has a U shape with a flow path portion 8a. The bent flow path portion 8a is a portion where water contained in the reformed gas is condensed and water can be easily pooled when the reformed gas flows in the reformed gas supply pipe 8. For this reason, it is desirable that the combustion catalyst 15A is provided in a region (here, a region extending horizontally) including the respective curved flow path portions 8a in the reformed gas supply pipe 8. Note that platinum, iron, or the like is used as the combustion catalyst 15A.

  An air introduction pipe 16 for introducing catalytic combustion air is connected to the upstream side of the combustion catalyst 15 </ b> A in the reformed gas supply pipe 8. The air introduction pipe 16 is provided with an electromagnetic valve 17 that adjusts the amount of catalyst combustion air introduced. When the catalytic combustion air is supplied to the combustion catalyst 15A, the fuel such as hydrogen, carbon monoxide and methane in the reformed gas and the catalytic combustion air undergo a partial oxidation reaction on the surface of the combustion catalyst 15A, and the thermal energy is increased. appear. Then, the reformed gas is heated by the reaction heat at this time, and accordingly, a horizontally extending region in the reformed gas supply pipe 8 is heated.

  In addition, a combustion catalyst 15B similar to the combustion catalyst 15A is filled in a gas flow path through which the reformed gas is supplied in the SOFC stack 3, specifically, between the anode 3a and a separator (not shown). ing. An air introduction pipe 18 for introducing catalytic combustion air is connected to the upstream side of the combustion catalyst 15B in the gas flow path. The air introduction pipe 18 is provided with an electromagnetic valve 19 that adjusts the amount of catalyst combustion air introduced.

  Further, the gas exhaust pipe 10 is filled with a combustion catalyst 15C similar to the combustion catalyst 15A. At this time, when the gas exhaust pipe 10 has a curved flow path portion that bends upward with respect to the direction of gravitational acceleration, it is desirable to fill the region including the curved flow path portion with the combustion catalyst 15C. . An air introduction pipe 20 for introducing catalytic combustion air is connected to the upstream side of the combustion catalyst 15 </ b> C in the gas exhaust pipe 10. The air introduction pipe 20 is provided with an electromagnetic valve 21 that adjusts the amount of catalyst combustion air introduced.

  Thus, using the combustion catalysts 15A to 15C as a heat source for heating the inside of the reformed gas supply pipe 8, the gas flow path in the SOFC stack 3, and the gas exhaust pipe 10 is advantageous in terms of space, and the large scale of the system. Can be avoided.

  The module container 5 includes an inner housing 22 and an outer housing 23 disposed outside the inner housing 22, and a heat insulating material 24 is interposed between the inner housing 22 and the outer housing 23. As the heat insulating material 24, silica, alumina, or the like is used.

  The fuel cell system 1 includes a plurality of temperature sensors 25 that detect temperatures in the reformed gas supply pipe 8, the gas flow paths in the SOFC stack 3 and the gas exhaust pipe 10, and the fuel cell system 1 during operation. And a control device 26 for controlling the whole. For example, a thermocouple is used as the temperature sensor 25.

  The control device 26 controls the supply amounts of raw fuel and water (steam) by controlling the electromagnetic valves 74 and 75, and controls the supply amounts of raw fuel and water (steam) by controlling the electromagnetic valves 84 and 85. The amount of power generation air introduced is controlled by controlling the electromagnetic valve 11, and the amount of catalytic combustion air introduced is controlled by controlling the electromagnetic valves 17, 19, and 21.

  FIG. 3 is a flowchart showing a control processing procedure executed by the control device 26 when the fuel cell system 1 is started. The execution of this control process is started, for example, by operating a start switch (not shown). Hereinafter, the operation method at the time of starting of the fuel cell system 1 will be described with reference to the flowchart shown in FIG.

  First, for example, the fuel vaporizers 76 and 86 and the water vaporizers 73 and 83 are heated to a predetermined temperature by a heat source such as a burner or a heater disposed in the vicinity of the fuel vaporizers 76 and 86 and the water vaporizers 73 and 83. . Subsequently, the start / stop reformer 4 is heated to a predetermined temperature by a heat source such as a burner or a heater (not shown) disposed in the vicinity of the start / stop reformer 4.

  Subsequently, the electromagnetic valves 17, 19, and 21 are controlled to supply catalytic combustion air to the combustion catalysts 15A to 15C (procedure 101). Then, by controlling the electromagnetic valves 84 and 85 and supplying raw fuel and steam to the start / stop reformer 4, the start / stop reforming material is supplied to the start / stop reformer 4. Supply (procedure 102). Then, the reformed gas is generated by the start / stop reformer 4, and this reformed gas is supplied to the anode 3 a of the SOFC stack 3 via the power reformer 2 and the reformed gas supply pipe 8. Thereby, the gas flow paths in the reformed gas supply pipe 8 and the SOFC stack 3 are heated. At this time, since the reformed reformed gas is continuously supplied to the anode 3a, the oxidative deterioration of the anode 3a is prevented.

  Further, the electromagnetic valve 11 is controlled to supply power generation air to the cathode 3b of the SOFC stack 3 (procedure 103). The start of the supply of power generation air may be executed before the procedure 102 or simultaneously with the procedure 102.

  Subsequently, the electromagnetic valves 17, 19, 21 are subjected to, for example, PID control based on the detection signals of the temperature sensors 25, and the inside of the reformed gas supply pipe 8, the gas flow path in the SOFC stack 3, and the gas exhaust pipe 10. The temperature is maintained at a temperature not lower than the boiling point of water (for example, 100 ° C.) and not higher than the oxidation deterioration point (for example, 400 ° C.) of the anode 3a (procedure 104). At this time, since the gas flow path in the SOFC stack 3 is maintained at a temperature lower than the oxidation deterioration point of the anode 3a, the battery cell is cracked due to the stress change caused by the expansion of the anode 3a due to the reoxidation of the anode 3a. Is prevented. In the gas exhaust pipe 10, the temperature may not be particularly lower than the oxidation deterioration point of the anode 3 a as long as the temperature is equal to or higher than the boiling point of water. However, due to heat transfer from the gas exhaust pipe 10 to the SOFC stack 3. In order not to raise the temperature of the anode 3a, the temperature is preferably equal to or lower than the oxidation deterioration point of the anode 3a.

  Thereafter, the temperature inside the module container 5 is raised by the combustion heat of the anode off gas from the SOFC stack 3 or a heater. When the temperature of the power generation reformer 2 reaches a predetermined temperature (about 550 to 750 ° C.), the electromagnetic valves 74 and 75 are controlled to feed the raw fuel and steam toward the power generation reformer 2. Is supplied to the power reformer 2 (procedure 105). Then, the reformed gas is generated by the power reformer 2, and this reformed gas is supplied to the anode 3 a of the SOFC stack 3 through the reformed gas supply pipe 8.

  Subsequently, the supply of the starting / stopping reforming raw material to the starting / stopping reformer 4 is stopped by stopping the supply of raw fuel and steam by controlling the electromagnetic valves 84 and 85 (procedure 106). ). Thereafter, after the temperature of the SOFC stack 3 is raised to a predetermined temperature, electric power is taken out from the SOFC stack 3 to start power generation by the SOFC stack 3. Further, the heat output from the heat source provided in or near the start / stop reformer 4 is stopped. Further, the electromagnetic valves 17, 19, and 21 are controlled to stop the supply of catalytic combustion air (procedure 107).

  By the way, the reformed gas generated in the reformed gas supply pipe 8, the gas flow path in the SOFC stack 3, and the gas exhaust pipe 10 is lower than the boiling point of water. When gas is supplied to the SOFC stack 3 through the reformed gas supply pipe 8, moisture contained in the reformed gas and off-gas is condensed, so that the reformed gas supply pipe 8, the SOFC stack 3, and the gas exhaust pipe 10 are condensed. A puddle will be generated inside. In this case, equipment such as the reformed gas supply pipe 8 and the SOFC stack 3 may be damaged due to bumping of the water pool. In addition, when the fuel cell system 1 is used in a cold region, the water pool freezes, so that the equipment is more easily damaged.

  On the other hand, in the present embodiment, supply of catalytic combustion air to the combustion catalysts 15A to 15C is started, and further, the reformed gas is supplied to the SOFC stack 3, whereby the reformed gas supply pipe 8 and the SOFC stack 3 are supplied. The temperature of the inner gas flow path and the inside of the gas exhaust pipe 10 is raised and maintained at a temperature equal to or higher than the boiling point of water. For this reason, when the reformed gas flows through the reformed gas supply pipe 8 and the SOFC stack 3, even if the reformed gas contains moisture, the moisture is vaporized (evaporated) by heat. Condensation of moisture in the reformed gas is prevented. Further, when the anode off-gas from the SOFC stack 3 flows inside the gas exhaust pipe 10, even if moisture is contained in the off-gas, the moisture is vaporized by heat, thus preventing condensation of moisture in the off-gas. Is done. Therefore, water does not accumulate inside the reformed gas supply pipe 8, the SOFC stack 3, and the gas exhaust pipe 10, and damage of equipment due to the water accumulation can be prevented.

  FIG. 4 is a flowchart showing a control processing procedure executed by the control device 26 when the fuel cell system 1 is stopped. The execution of this control process is started, for example, by operating a stop switch (not shown). Hereinafter, the operation method when the fuel cell system 1 is stopped will be described with reference to the flowchart shown in FIG.

  First, for example, the start / stop reformer 4 is heated to a predetermined temperature by a heater (not shown) disposed in the vicinity of the start / stop reformer 4. In addition, the supply amount of the reforming raw material for power generation to the power reformer 2 is reduced by controlling the electromagnetic valves 74 and 75 to reduce the supply amount of raw fuel and water vapor. Thereby, the supply amount of the reformed gas generated by the power reformer 2 is reduced.

  Then, by controlling the electromagnetic valves 84 and 85 and supplying a small amount of raw fuel and steam to the start / stop reformer 4, a small amount of start / stop is supplied to the start / stop reformer 4. A reforming raw material is supplied (procedure 111). Then, the reformed gas is generated by the start / stop reformer 4, and a small amount of the reformed gas is supplied to the anode 3a of the SOFC stack 3.

  Further, the supply of the reforming raw material for power generation to the power reformer 2 is stopped by controlling the electromagnetic valves 74 and 75 to stop the supply of raw fuel and steam (procedure 112). As a result, the supply of the reformed gas generated in the power generation reformer 2 is stopped.

  Subsequently, for example, by controlling the electromagnetic valve 11 and increasing the amount of air supplied to the cathode 3b of the SOFC stack 3, the temperature drop in the module container 5 is started (procedure 113). Note that this procedure may be executed before the procedure 112.

  Then, based on the detection signal of each temperature sensor 25, the electromagnetic valves 17, 19, and 21 are subjected to PID control, for example, so that the inside of the reformed gas supply pipe 8, the gas flow path in the SOFC stack 3, and the gas exhaust pipe 10 are watered. The temperature is kept above the boiling point of the anode 3a and below the oxidation deterioration point of the anode 3a (procedure 114). Note that the gas exhaust pipe 10 need not be at a temperature not higher than the oxidation deterioration point of the anode 3a as long as the temperature is not lower than the boiling point of water.

  After the temperature inside the SOFC stack 3 becomes lower than the oxidation deterioration point of the anode 3a, the electromagnetic valves 84 and 85 are controlled to stop the supply of raw fuel and water vapor, so that the starter / stop reformer 4 is supplied. The supply of the reforming raw material for starting and stopping is stopped (procedure 115). Thereby, the supply of the reformed gas from the start / stop reformer 4 to the SOFC stack 3 is stopped. Here, since the reformed gas is continuously supplied to the anode 3a while the temperature of the gas flow path in the SOFC stack 3 is lowered to a temperature below the oxidation deterioration point of the anode 3a, the oxidation deterioration of the anode 3a is prevented.

  Further, the heat output from the heat source provided in or near the start / stop reformer 4 is stopped. Furthermore, the supply of catalytic combustion air is stopped by controlling the electromagnetic valves 17, 19, and 21 (procedure 116).

  By the way, when the temperature inside the module container 5 is lowered to a predetermined temperature, the temperature inside the SOFC stack 3 is less likely to drop than inside the reformed gas supply pipe 8 and the gas exhaust pipe 10. Therefore, although the temperature in the SOFC stack 3 is higher than the boiling point of water, the temperatures in the reformed gas supply pipe 8 and the gas exhaust pipe 10 are lower than the boiling point of water. May be. In this state, when the reformed gas generated by the start / stop reformer 4 is supplied to the SOFC stack 3 through the reformed gas supply pipe 8, the reformed gas is contained in the reformed gas in the reformed gas supply pipe 8. Since water contained in the water condenses, a puddle is formed. In this case, as described above, equipment such as the reformed gas supply pipe 8 may be damaged.

  In contrast, in the present embodiment, while the reformed gas generated by the start / stop reformer 4 is supplied to the SOFC stack 3, the gas flow in the reformed gas supply pipe 8 and the SOFC stack 3 is maintained. The passage and the gas exhaust pipe 10 are maintained at a temperature equal to or higher than the boiling point of water. For this reason, even if moisture is contained in the reformed gas or off-gas, the moisture is vaporized by heat, so that condensation of the moisture is prevented. Therefore, water does not accumulate inside the reformed gas supply pipe 8, the SOFC stack 3, and the gas exhaust pipe 10, and damage of equipment due to the water accumulation can be prevented.

  As described above, according to the present embodiment, it is possible to prevent a water pool from being generated due to condensation of moisture contained in the reformed gas or off gas. Thereby, it becomes possible to realize a highly reliable fuel cell system 1.

  In addition, since the reformed gas supply pipe 8, the SOFC stack 3, and the gas exhaust pipe 10 are individually heated, less energy is consumed than when a wide range of heating is performed. In addition, when the temperature of the gas flow path in the SOFC stack 3 is less likely to be lower than that of the reformed gas supply pipe 8 and the gas exhaust pipe 10 when the temperature in the module container 5 is lowered, the reformed gas supply pipe 8 and Fine control such as heating the inside of the gas exhaust pipe 10 but not heating the gas flow path in the SOFC stack 3 becomes possible.

  In the first embodiment, the inside of the reformed gas supply pipe 8, the gas flow path in the SOFC stack 3, and the gas exhaust pipe 10 are all heated. The gas flow path in the SOFC stack 3 and at least one in the gas exhaust pipe 10 may be heated.

  FIG. 5 is a system configuration diagram showing a second embodiment of the fuel cell system according to the present invention. In the figure, the same or equivalent elements as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  In the figure, the fuel cell system 30 of the present embodiment includes the above-described combustion catalysts 15A to 15C as means for independently heating the inside of the reformed gas supply pipe 8, the gas flow path in the SOFC stack 3, and the gas exhaust pipe 10. Instead of 15C, heaters 31A to 31C are provided. The heaters 31A to 31C are arranged in the vicinity of the reformed gas supply pipe 8, the SOFC stack 3, and the gas exhaust pipe 10, respectively.

  The fuel cell system 30 includes a control device 32 instead of the control device 26 described above. The control device 32 controls the supply amounts of the raw fuel and the water vapor by controlling the electromagnetic valves 74 and 75, and controls the supply amounts of the raw fuel and the water vapor by controlling the electromagnetic valves 84 and 85. In addition to the function of controlling the amount of power generation air introduced by controlling the power supply, it has a function of controlling the energization of the heaters 31A to 31C.

  FIG. 6 is a flowchart showing a control processing procedure executed by the control device 32 when the fuel cell system 30 is activated. Hereinafter, the operation method at the time of starting of the fuel cell system 30 will be described using the flowchart shown in FIG.

  In the figure, the fuel vaporizers 76 and 86 and the water vaporizers 73 and 83 are heated to a predetermined temperature, and the start / stop reformer 4 is heated to a predetermined temperature, and then the heaters 31A to 31C are energized. Then, the temperature in the reformed gas supply pipe 8, the gas flow path in the SOFC stack 3, and the gas exhaust pipe 10 is increased (procedure 121). At this time, for example, PID control is performed on the heaters 31 </ b> A to 31 </ b> C based on the detection signals of the temperature sensors 25, and the gas flow paths in the reformed gas supply pipe 8, the SOFC stack 3, and the gas exhaust pipe 10 are watered. Is maintained at a temperature not lower than the boiling point of the anode 3a and not higher than the oxidation deterioration point of the anode 3a. Here, since the gas flow path in the SOFC stack 3 is maintained at a temperature equal to or lower than the oxidation deterioration point of the anode 3a, the oxidation deterioration of the anode 3a is prevented.

  Then, by controlling the electromagnetic valves 84 and 85 and supplying raw fuel and steam to the start / stop reformer 4, the start / stop reforming material is supplied to the start / stop reformer 4. Supply (procedure 122). Then, the reformed gas is generated by the start / stop reformer 4, and this reformed gas is supplied to the anode 3 a of the SOFC stack 3. Further, the electromagnetic valve 11 is controlled to supply power generation air to the cathode 3b of the SOFC stack 3 (procedure 123).

  Thereafter, the inside of the module container 5 is heated by the combustion heat of the anode off gas from the SOFC stack 3. When the temperature of the power reformer 2 reaches a predetermined temperature, the electromagnetic valves 74 and 75 are controlled to supply raw fuel and steam to the power reformer 2, thereby improving the power reformer. The reforming raw material for power generation is supplied to the mass device 2 (procedure 124). Then, the reformed gas is generated by the power generation reformer 2, and this reformed gas is supplied to the anode 3 a of the SOFC stack 3.

  Subsequently, the supply of the starting / stopping reforming raw material to the starting / stopping reformer 4 is stopped by stopping the supply of raw fuel and steam by controlling the electromagnetic valves 84 and 85 (procedure 125). ). Thereafter, after the temperature of the SOFC stack 3 is raised to a predetermined temperature, electric power is taken out from the SOFC stack 3 to start power generation by the SOFC stack 3. Further, the energization of the heaters 31A to 31C is stopped (procedure 126).

  As described above, when the fuel cell system 30 is started, the gas in the reformed gas supply pipe 8 and the SOFC stack 3 is supplied before the reformed gas generated by the start / stop reformer 4 is supplied to the SOFC stack 3. The flow path and the gas exhaust pipe 10 are heated up to a temperature equal to or higher than the boiling point of water. For this reason, when the reformed gas is supplied to the SOFC stack 3 thereafter, condensation of moisture contained in the reformed gas is surely prevented. In addition, condensation of moisture contained in the off-gas from the SOFC stack 3 is reliably prevented. Thereby, generation | occurrence | production of the water pool by the condensation of the water | moisture content contained in reformed gas or off gas can be prevented.

  FIG. 7 is a flowchart showing a control processing procedure executed by the control device 32 when the fuel cell system 30 is stopped. Hereinafter, the operation method when the fuel cell system 30 is stopped will be described with reference to the flowchart shown in FIG.

  In the figure, first, the start / stop reformer 4 is heated to a predetermined temperature. In addition, the supply amount of the reforming raw material for power generation to the power reformer 2 is reduced by controlling the electromagnetic valves 74 and 75 to reduce the supply amount of raw fuel and water vapor. Thereby, the supply amount of the reformed gas generated by the power reformer 2 is reduced.

  Then, by controlling the electromagnetic valves 84 and 85 to supply a small amount of raw fuel and steam, a small amount of starting / stopping reforming raw material is supplied to the starting / stopping reformer 4 (procedure 131). Then, the reformed gas is generated by the start / stop reformer 4, and a small amount of the reformed gas is supplied to the anode 3a of the SOFC stack 3.

  Further, the supply of the power generation reforming raw material to the power generation reformer 2 is stopped by controlling the electromagnetic valves 74 and 75 to stop the supply of the raw fuel and the water vapor (procedure 132). As a result, the supply of the reformed gas generated by the power generation reformer 2 is stopped.

  Subsequently, for example, by controlling the electromagnetic valve 11 and increasing the amount of air supplied to the cathode 3b of the SOFC stack 3, the temperature drop in the module container 5 is started (procedure 133).

  Then, the energization of the heaters 31 </ b> A to 31 </ b> C is controlled by, for example, PID based on the detection signals of the temperature sensors 25, and the water in the reformed gas supply pipe 8, the gas flow path in the SOFC stack 3 and the gas exhaust pipe 10 The temperature is kept above the boiling point and below the oxidation deterioration point of the anode 3a (procedure 134).

  After the temperature inside the SOFC stack 3 becomes lower than the oxidation deterioration point of the anode 3a, the electromagnetic valves 84 and 85 are controlled to stop the supply of raw fuel and water vapor, so that the starter / stop reformer 4 is supplied. The supply of the starting / stopping reforming raw material is stopped (procedure 135). Thereby, the supply of the reformed gas from the start / stop reformer 4 to the SOFC stack 3 is stopped. Further, the energization of the heaters 31A to 31C is stopped (procedure 136).

  Thus, when the fuel cell system 30 is stopped, while the reformed gas generated by the start / stop reformer 4 is being supplied to the SOFC stack 3, the reformed gas supply pipe 8 and the SOFC stack 3 The gas flow path and the inside of the gas exhaust pipe 10 are maintained at a temperature equal to or higher than the boiling point of water. Accordingly, the condensation of moisture contained in the reformed gas and the off-gas from the SOFC stack 3 is prevented, so that it is possible to prevent the accumulation of water due to the condensation of the moisture.

  FIG. 8 is a system configuration diagram showing a third embodiment of the fuel cell system according to the present invention. In the figure, the same or equivalent elements as those in the first and second embodiments are denoted by the same reference numerals, and the description thereof is omitted.

  In the figure, the fuel cell system 40 of this embodiment includes a burner 41 and a heater 42 that heat the entire interior of the module container 5 including the reformed gas supply pipe 8, the SOFC stack 3, and the gas exhaust pipe 10. The burner 41 is installed, for example, at the bottom of the module container 5. The heater 42 is installed on the side of the module container 5, for example. In addition, the quantity, installation site | part, etc. of the burner 41 and the heater 42 are not specifically limited to said thing.

  The fuel cell system 40 includes a plurality of temperature sensors 25 and a control device 43. In addition to the inside of the reformed gas supply pipe 8, the SOFC stack 3 and the gas exhaust pipe 10, the temperature sensor 25 is provided in the module container 5 where water tends to accumulate due to condensation of moisture contained in the anode off-gas and cathode off-gas from the SOFC stack 3. It is also arranged at the bottom of the. In addition to this, the temperature sensor 25 may be appropriately provided, for example, at a location where the temperature tends to be low or a location where water is likely to accumulate.

  The control device 43 controls the supply amounts of the raw fuel and the steam by controlling the electromagnetic valves 74 and 75, and controls the supply amounts of the raw fuel and the steam by controlling the electromagnetic valves 84 and 85. In addition to the function of controlling the amount of power generation air introduced by controlling the above, it has the function of controlling the ignition of the burner 41 and the energization of the heater 42.

  FIG. 9 is a flowchart showing a control processing procedure executed by the control device 43 when the fuel cell system 40 is started. Hereinafter, the operation method at the time of starting of the fuel cell system 40 will be described using the flowchart shown in FIG.

  In the figure, after the fuel vaporizers 76 and 86 and the water vaporizers 73 and 83 are heated to a predetermined temperature, and the starter / stop reformer 4 is heated to a predetermined temperature, the burner 41 is ignited and the heater is heated. 42 is energized to raise the temperature inside the module container 5 (procedure 141). At this time, the ignition of the burner 41 and the energization of the heater 42 are controlled by, for example, PID based on the detection signal of each temperature sensor 25, and the module container including the inside of the reformed gas supply pipe 8, the SOFC stack 3 and the gas exhaust pipe 10. 5 is maintained at a temperature not lower than the boiling point of water and not higher than the oxidation deterioration point of the anode 3a. In addition, about the bottom part in the module container 5, if it is the temperature more than the boiling point of water, it may not be the temperature below especially the oxidation deterioration point of the anode 3a.

  Then, by controlling the electromagnetic valves 84 and 85 and supplying raw fuel and steam to the start / stop reformer 4, the start / stop reforming material is supplied to the start / stop reformer 4. Supply (procedure 142). Then, the reformed gas generated by the start / stop reformer 4 is supplied to the anode 3 a of the SOFC stack 3. Further, the electromagnetic valve 11 is controlled to supply power generation air to the cathode 3b of the SOFC stack 3 (procedure 143).

  Thereafter, the inside of the module container 5 is heated by the combustion heat of off gas from the SOFC stack 3 or the like. When the temperature of the power reformer 2 reaches a predetermined temperature, the electromagnetic valves 74 and 75 are controlled to supply raw fuel and steam to the power reformer 2, thereby improving the power reformer. The reforming raw material for power generation is supplied to the mass device 2 (procedure 144). Then, the reformed gas generated by the power reformer 2 is supplied to the anode 3 a of the SOFC stack 3.

  Subsequently, the supply of the starting / stopping reforming raw material to the starting / stopping reformer 4 is stopped by stopping the supply of raw fuel and steam by controlling the electromagnetic valves 84 and 85 (procedure 145). ). Thereafter, after the temperature of the SOFC stack 3 is raised to a predetermined temperature, electric power is taken out from the SOFC stack 3 to start power generation by the SOFC stack 3. Further, the ignition of the burner 41 and the energization of the heater 42 are stopped (procedure 146).

  As described above, when the fuel cell system 40 is started, before the reformed gas generated by the start / stop reformer 4 is supplied to the SOFC stack 3, the entire interior of the module container 5 is set to a temperature equal to or higher than the boiling point of water. Raise the temperature until For this reason, when the reformed gas is subsequently supplied to the SOFC stack 3, the condensation of moisture contained in the reformed gas and off-gas is prevented. Further, off-gas combustion gas is generated by igniting off-gas in the module container 5, or anode off-gas and cathode off-gas are mixed and burned outside the module container 5 to generate off-gas combustion gas, which is generated in the module container 5. In some cases, the moisture contained in the off-gas combustion gas is prevented from condensing. As a result, it is possible to prevent water pools from occurring in the reformed gas supply pipe 8, the SOFC stack 3, the gas exhaust pipe 10, and the bottom of the module container 5.

  FIG. 10 is a flowchart showing a control processing procedure executed by the control device 43 when the fuel cell system 40 is stopped. Hereinafter, the operation method when the fuel cell system 40 is stopped will be described with reference to the flowchart shown in FIG.

  In the figure, first, the start / stop reformer 4 is heated to a predetermined temperature. In addition, the supply amount of the reforming raw material for power generation to the power reformer 2 is reduced by controlling the electromagnetic valves 74 and 75 to reduce the supply amount of raw fuel and water vapor. Thereby, the supply amount of the reformed gas generated by the power reformer 2 is reduced.

  Then, by controlling the electromagnetic valves 84 and 85 and supplying a small amount of raw fuel and steam to the start / stop reformer 4, a small amount of start / stop is supplied to the start / stop reformer 4. A reforming raw material is supplied (procedure 151). Then, a small amount of the reformed gas generated by the start / stop reformer 4 is supplied to the anode 3a of the SOFC stack 3.

  Further, the supply of the reforming raw material for power generation to the power reformer 2 is stopped by controlling the electromagnetic valves 74 and 75 to stop the supply of raw fuel and water vapor (procedure 152). As a result, the supply of the reformed gas generated by the power generation reformer 2 is stopped.

  Subsequently, for example, by controlling the electromagnetic valve 11 and increasing the amount of air supplied to the cathode 3b of the SOFC stack 3, the temperature drop in the module container 5 is started (procedure 153).

  Then, the ignition of the burner 41 and the energization of the heater 42 are subjected to, for example, PID control based on the detection signal of each temperature sensor 25, and the module container 5 including the inside of the reformed gas supply pipe 8, the SOFC stack 3 and the gas exhaust pipe 10. Is maintained at a temperature not lower than the boiling point of water and not higher than the oxidation deterioration point of the anode 3a (procedure 154). In addition, about the bottom part in the module container 5, if it is the temperature more than the boiling point of water, it may not be the temperature below especially the oxidation deterioration point of the anode 3a.

  After the temperature inside the SOFC stack 3 becomes lower than the oxidation deterioration point of the anode 3a, the electromagnetic valves 84 and 85 are controlled to stop the supply of raw fuel and water vapor, so that the starter / stop reformer 4 is supplied. The supply of the starting / stopping reforming raw material is stopped (procedure 155). Thereby, the supply of the reformed gas from the start / stop reformer 4 to the SOFC stack 3 is stopped. Further, the ignition of the burner 41 and the energization of the heater 42 are stopped (procedure 156).

  As described above, when the fuel cell system 40 is stopped, while the reformed gas generated by the start / stop reformer 4 is being supplied to the SOFC stack 3, the entire interior of the module container 5 has a temperature equal to or higher than the boiling point of water. Maintained. Therefore, condensation of moisture contained in the reformed gas and offgas (including offgas combustion gas) is prevented. As a result, it is possible to prevent water pools from occurring in the reformed gas supply pipe 8, the SOFC stack 3, the gas exhaust pipe 10, and the bottom of the module container 5.

  In addition, in the said 3rd Embodiment, although it was set as the structure which heats the whole inside of the module container 5, the structure which heats at least the bottom part in the module container 5 may be sufficient.

  FIG. 11 is a system configuration diagram showing a fourth embodiment of the fuel cell system according to the present invention. In the figure, the same or equivalent elements as those in the first and second embodiments are denoted by the same reference numerals, and the description thereof is omitted.

  In the figure, the fuel cell system 50 of the present embodiment includes a heater 51A for heating the downstream side of the fuel vaporizer 76 in the raw material introduction pipe 6, a heater 51B for heating the water vapor supply pipe 71, and a fuel in the raw material introduction pipe 12. A heater 52A for heating the downstream side of the vaporizer 86 and a heater 52B for heating the water vapor supply pipe 81 are provided. Although not particularly illustrated, it is desirable to provide a heater for heating the upstream side of the fuel vaporizer 76 in the raw material introduction pipe 6 and a heater for heating the upstream side of the fuel vaporizer 86 in the raw material introduction pipe 12. Moreover, when these piping has the curved flow path part bent upwards with respect to the direction of gravity acceleration, it is desirable to heat the area | region containing the curved flow path part.

  The fuel cell system 50 includes a plurality of temperature sensors 25 and a control device 53. The temperature sensor 25 includes the inside of the downstream portion of the fuel vaporizer 76 in the raw material introduction pipe 6, the inside of the water vapor supply pipe 71, the inside of the downstream portion of the fuel vaporizer 86 in the raw material introduction pipe 12, and the inside of the water vapor supply pipe 81. Is arranged. In addition, the temperature sensor 25 may be appropriately provided in these pipes, for example, at a place where the temperature tends to be low or a place where water is likely to accumulate.

  The control device 53 controls the supply amounts of raw fuel and water vapor by controlling the electromagnetic valves 74 and 75, and controls the supply amounts of raw fuel and water vapor by controlling the electromagnetic valves 84 and 85. In addition to the function of controlling the amount of power generation air introduced by controlling the power, it has a function of controlling the energization of the heaters 51A to 52B.

  FIG. 12 is a flowchart showing a control processing procedure executed by the control device 53 when the fuel cell system 50 is activated. Hereinafter, the operation method at the time of starting of the fuel cell system 50 will be described using the flowchart shown in FIG.

  In the figure, first, the fuel vaporizers 76 and 86 and the water vaporizers 73 and 83 are heated to a predetermined temperature, and further the start / stop reformer 4 is heated to a predetermined temperature.

  Then, the heaters 51A to 52B are energized to raise the temperature inside the raw material introduction pipe 6, the water vapor supply pipe 71, the raw material introduction pipe 12, and the water vapor supply pipe 81 (procedure 161). At this time, the energization of the heaters 51A to 52B is controlled by, for example, PID based on the detection signal of each temperature sensor 25, and the inside of the raw material introduction pipe 6, the water vapor supply pipe 71, the raw material introduction pipe 12 and the water vapor supply pipe 81 is within a predetermined range. Hold at a temperature of. Specifically, the inside of the water vapor supply pipes 71 and 81 is maintained at a temperature equal to or higher than the boiling point of water, and the inside of the raw material introduction pipes 6 and 12 is equal to or higher than the higher temperature of the boiling points of water and raw fuel. Hold at a temperature of.

  Then, by controlling the electromagnetic valves 84 and 85 and supplying raw fuel and steam to the start / stop reformer 4, the start / stop reforming material is supplied to the start / stop reformer 4. Supply (procedure 162). Then, the reformed gas generated by the start / stop reformer 4 is supplied to the anode 3 a of the SOFC stack 3. Further, the electromagnetic valve 11 is controlled to supply power generation air to the cathode 3b of the SOFC stack 3 (procedure 163).

  Thereafter, the inside of the module container 5 is heated by the combustion heat of the anode off gas from the SOFC stack 3. When the temperature of the power reformer 2 reaches a predetermined temperature, the electromagnetic valves 74 and 75 are controlled to supply raw fuel and steam to the power reformer 2, thereby improving the power reformer. The reforming raw material for power generation is supplied to the mass device 2 (procedure 164). Then, the reformed gas generated by the power reformer 2 is supplied to the anode 3 a of the SOFC stack 3.

  Subsequently, the supply of the starting / stopping reforming raw material to the starting / stopping reformer 4 is stopped by stopping the supply of raw fuel and steam by controlling the electromagnetic valves 84 and 85 (procedure 165). ). Thereafter, after the temperature of the SOFC stack 3 is raised to a predetermined temperature, electric power is taken out from the SOFC stack 3 to start power generation by the SOFC stack 3. Further, energization of the heaters 51A to 52B is stopped (procedure 166).

  By the way, when so-called coking occurs in which carbon is deposited on the reforming catalyst surface of the reformer during the steam reforming reaction, the reforming catalyst may be deteriorated to inhibit the reforming reaction. In order to prevent this, when supplying the reforming material to the reformer, first, only steam is supplied to the reformer, and then the reforming material in which raw fuel and steam are mixed is supplied to the reformer. It is preferable to supply. At this time, when the water inside the raw material introduction pipe 6, the water vapor supply pipe 71, the raw material introduction pipe 12, and the water vapor supply pipe 81 is lower than the boiling point of water and the water vapor flows through these pipes, the water vapor condenses. For this reason, a puddle is generated in the pipe. In this case, as described above, the piping may be damaged due to the bumping of the water pool.

  On the other hand, in the present embodiment, before the steam is first supplied to the start / stop reformer 4 and the power reformer 2, the water vapor supply pipes 71 and 81 are heated to the boiling point of water by the heaters 51 </ b> B and 52 </ b> B. The temperature is raised to the above temperature, and the temperature inside the raw material introduction pipes 6 and 12 is raised by the heaters 51A and 52A until the temperature becomes higher than the higher one of the boiling points of water and raw fuel. Therefore, when water vapor is subsequently supplied to the starter / stop reformer 4 through the water vapor supply pipe 81 and the raw material introduction pipe 12, the water vapor is further contained in the water vapor supply pipe 71 and the raw material introduction pipe 6. When it is supplied to the power reformer 2 through the steam, condensation of water vapor is prevented. Thereby, generation | occurrence | production of the water pool by condensation of water vapor | steam can be prevented. Further, when the raw fuel passes through the raw material introduction pipes 6 and 12, the condensation of the raw fuel is also prevented.

  FIG. 13 is a flowchart showing a control processing procedure executed by the control device 53 when the fuel cell system 50 is stopped. Hereinafter, the operation method when the fuel cell system 50 is stopped will be described with reference to the flowchart shown in FIG.

  In the figure, first, the start / stop reformer 4 is heated to a predetermined temperature. In addition, the supply amount of the reforming raw material for power generation to the power reformer 2 is reduced by controlling the electromagnetic valves 74 and 75 to reduce the supply amount of raw fuel and water vapor. Thereby, the supply amount of the reformed gas generated by the power reformer 2 is reduced.

  Then, by controlling the electromagnetic valves 84 and 85 and supplying a small amount of raw fuel and steam to the start / stop reformer 4, a small amount of start / stop is supplied to the start / stop reformer 4. A reforming raw material is supplied (procedure 171). Then, a small amount of the reformed gas generated by the start / stop reformer 4 is supplied to the anode 3a of the SOFC stack 3.

  Further, the supply of the reforming raw material for power generation to the power reformer 2 is stopped by controlling the electromagnetic valves 74 and 75 to stop the supply of raw fuel and water vapor (procedure 172). As a result, the supply of the reformed gas generated by the power generation reformer 2 is stopped.

  Subsequently, for example, by controlling the electromagnetic valve 11 and increasing the amount of air supplied to the cathode 3b of the SOFC stack 3, the temperature drop in the module container 5 is started (procedure 173). Then, the energization of the heaters 51A to 52B is controlled by, for example, PID based on the detection signal of each temperature sensor 25, and the inside of the raw material introduction pipe 6, the water vapor supply pipe 71, the raw material introduction pipe 12, and the water vapor supply pipe 81 is within a predetermined range. Hold at temperature (procedure 174). Specifically, the inside of the water vapor supply pipes 71 and 81 is maintained at a temperature equal to or higher than the boiling point of water, and the inside of the raw material introduction pipes 6 and 12 is equal to or higher than the higher temperature of the boiling points of water and raw fuel. Hold at a temperature of.

  After the temperature inside the SOFC stack 3 becomes lower than the oxidation deterioration point of the anode 3a, the electromagnetic valves 84 and 85 are controlled to stop the supply of raw fuel and water vapor, so that the starter / stop reformer 4 is supplied. The supply of the starting / stopping reforming raw material is stopped (procedure 175). Thereby, the supply of the reformed gas from the start / stop reformer 4 to the SOFC stack 3 is stopped. Further, the energization of the heaters 51A to 52B is stopped (procedure 176).

  When the supply of the reforming raw material to the reformer is stopped when such a system is stopped, in order to prevent the above-mentioned coking, the supply of raw fuel is first stopped and then the supply of steam is stopped. Is preferred. At this time, when water vapor flows through these pipes in a state where the temperature inside the raw material introduction pipe 6, the water vapor supply pipe 71, the raw material introduction pipe 12 and the water vapor supply pipe 72 is lower than the boiling point of water, the same as described above. Since water vapor is condensed, a puddle is generated.

  In contrast, in the present embodiment, the steam supply pipes 71 and 81 are kept at a temperature equal to or higher than the boiling point of water while the steam is supplied toward the power reformer 2 and the start / stop reformer 4. The inside of the raw material introduction pipes 6 and 12 is maintained at a temperature equal to or higher than the higher one of the boiling points of water and raw fuel. Accordingly, since the water vapor is prevented from condensing in the water vapor supply pipes 71 and 81 and the raw material introduction pipes 6 and 12, it is possible to prevent the occurrence of a water pool due to the water vapor condensation. In addition, the raw material introduction pipes 6 and 12 prevent the raw fuel from condensing.

  In the fourth embodiment, the inside of the raw material introduction pipe 6, the inside of the steam supply pipe 71, the inside of the raw material introduction pipe 12, and the inside of the steam supply pipe 81 are heated by the heaters 51A to 52B, respectively. As such, a burner may be used, or a combustion catalyst may be used as in the first embodiment. When a combustion catalyst is used, fuel and air for heating the combustion catalyst are required. As the fuel, a power generation reforming raw material or a starting / stopping reforming raw material may be used. May use another fuel gas.

  In the fourth embodiment, liquid raw fuel and water vapor are mixed to obtain a reformed raw material, and the reformed raw material is vaporized. For example, the raw fuel and water are vaporized separately, and the raw fuel is It is good also as a structure which mixes gas and water vapor | steam and produces | generates reforming raw material gas. In this case, since water vapor may enter the fuel supply pipe, it is preferable to heat the fuel supply pipe with a heating source such as a heater in addition to the raw material introduction pipe and the water vapor supply pipe. At this time, the inside of the fuel supply pipe is maintained at a temperature equal to or higher than the boiling point of the fuel.

  Although several preferred embodiments of the fuel cell system and the operation method thereof according to the present invention have been described above, the present invention is not limited to the above-described embodiments. For example, in the above embodiment, the power reformer 2 and the start / stop reformer 4 are both disposed in the module container 5. However, in the present invention, the power reformer 2 is provided in the module container 5. The system in which the start / stop reformer 4 is arranged outside the module container 5, or the power generation reformer 2 and the start / stop reformer 4 are both in the module container 5. The present invention can also be applied to a system arranged outside.

  The present invention can also be applied to a fuel cell system having only one reformer. In this case, at the time of starting the fuel cell system, for example, the reformed gas supply pipe 8 or the gas flow path in the SOFC stack 3 or the raw material introduction pipe or the steam supply pipe is maintained at a temperature higher than the boiling point of water. The raw material is introduced into the reformer, and the reformed gas generated in the reformer is supplied to the SOFC stack 3. On the other hand, when the fuel cell system is stopped, for example, reforming is performed with the gas flow path in the reformed gas supply pipe 8, the SOFC stack 3, the raw material introduction pipe, or the steam supply pipe maintained at a temperature equal to or higher than the boiling point of water. The supply of the reformed gas to the SOFC stack 3 is stopped by stopping the introduction of the reforming raw material into the reactor.

  In addition, the fuel cell system of the above embodiment includes a reformer that introduces a reforming raw material in which raw fuel and steam are mixed and causes the raw fuel to undergo a steam reforming reaction. In addition, the present invention can be applied to those equipped with a reformer that introduces a reforming raw material in which steam and air are mixed and causes the raw fuel to undergo a self-thermal reforming reaction. In this case, in order to prevent coking, for example, first, steam and air are sequentially supplied to the reformer, and then a reforming raw material in which raw fuel, steam and air are mixed is supplied to the reformer. Is preferred.

  Furthermore, although the said embodiment is a system regarding a solid oxide fuel cell (SOFC), this invention is applicable also to the molten carbonate fuel cell (MCFC) etc. which are the same high temperature type fuel cells as SOFC, for example. It is.

1 is a system configuration diagram showing a first embodiment of a fuel cell system according to the present invention. It is the schematic of the reformed gas supply pipe | tube shown in FIG. 2 is a flowchart showing a control processing procedure executed by a control device when the fuel cell system shown in FIG. 1 is started. 2 is a flowchart showing a control processing procedure executed by a control device when the fuel cell system shown in FIG. 1 is stopped. It is a system block diagram which shows 2nd Embodiment of the fuel cell system concerning this invention. It is a flowchart which shows the control processing procedure performed by a control apparatus at the time of starting of the fuel cell system shown in FIG. It is a flowchart which shows the control processing procedure performed by a control apparatus at the time of the stop of the fuel cell system shown in FIG. It is a system block diagram which shows 3rd Embodiment of the fuel cell system concerning this invention. It is a flowchart which shows the control processing procedure performed by a control apparatus at the time of starting of the fuel cell system shown in FIG. It is a flowchart which shows the control processing procedure performed by a control apparatus at the time of the stop of the fuel cell system shown in FIG. It is a system block diagram which shows 4th Embodiment of the fuel cell system concerning this invention. It is a flowchart which shows the control processing procedure performed by a control apparatus at the time of starting of the fuel cell system shown in FIG. It is a flowchart which shows the control processing procedure performed by a control apparatus at the time of the stop of the fuel cell system shown in FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Fuel cell system, 2 ... Power generation reformer, 3 ... Solid oxide fuel cell (SOFC) stack, 3a ... Anode, 4 ... Start / stop reformer, 5 ... Module container, 6 ... Raw material introduction Pipe (reformed raw material flow path), 8 ... reformed gas supply pipe (reformed gas flow path), 8a ... bent flow passage section, 10 ... gas exhaust pipe (downstream gas flow path), 12 ... raw material introduction pipe (modified) Material flow path), 15A to 15C ... combustion catalyst (heating means), 16 ... air introduction pipe (heating means), 17 ... electromagnetic valve (heating means), 18 ... air introduction pipe (heating means), 19 ... electromagnetic valve (Heating means), 20 ... air introduction pipe (heating means), 21 ... electromagnetic valve (heating means), 25 ... temperature sensor (temperature detection means), 26 ... control device (control means), 30 ... fuel cell system, 31A ˜31C ... heater (heating means), 32 ... control device (control means) , 40 ... Fuel cell system, 41 ... Burner (heating means), 42 ... Heater (heating means), 43 ... Control device (control means), 50 ... Fuel cell system, 51A, 51B ... Heater (heating means), 52A, 52B ... heater (heating means), 53 ... control device (control means), 70 ... fuel supply pipe (raw fuel flow path), 71 ... water vapor supply pipe (water vapor flow path), 80 ... fuel supply pipe (raw fuel flow path) ), 81... Steam supply pipe (steam channel).

Claims (16)

A reformer for reforming raw fuel to generate reformed gas;
A fuel cell stack connected to the reformer via a reformed gas flow path and generating power using the reformed gas generated by the reformer;
A fuel cell system comprising: the reformed gas channel, a gas channel in the fuel cell stack, and a heating unit that heats at least one of the downstream gas channels of the fuel cell stack.   The heating means includes a combustion catalyst provided in at least one of the reformed gas flow path, a gas flow path in the fuel cell stack, and the downstream gas flow path, and means for supplying air to the combustion catalyst. The fuel cell system according to claim 1, further comprising:   2. The fuel cell system according to claim 1, wherein the heating means is a heater or a burner arranged in the vicinity of at least one of the reformed gas flow path, the fuel cell stack, and the downstream gas flow path. At least one of the reformed gas flow path, the gas flow path in the fuel cell stack, and the downstream gas flow path has a curved flow path portion formed to bend upward with respect to the direction of gravity acceleration. ,
The fuel cell system according to any one of claims 1 to 3, wherein the heating unit heats a region including the bent flow path portion. Temperature detecting means for detecting at least one temperature of the reformed gas channel, a gas channel in the fuel cell stack, and the downstream gas channel;
Based on the detection signal of the temperature detection means, the heating is performed so that at least one temperature of the reformed gas passage, the gas passage in the fuel cell stack, and the downstream gas passage is equal to or higher than the boiling point of water. The fuel cell system according to claim 1, further comprising a control unit that controls the unit. A reformer for reforming raw fuel to generate reformed gas;
A fuel cell stack that generates electricity using the reformed gas generated by the reformer;
A container containing the fuel cell stack;
A fuel cell system comprising heating means for heating at least the bottom of the container. A reformer for reforming raw fuel to generate reformed gas;
A fuel cell stack that generates electricity using the reformed gas generated by the reformer;
A steam flow path for supplying steam toward the reformer;
A raw fuel flow path for supplying the raw fuel to the reformer;
A reforming material channel connected to the steam channel and the raw fuel channel, and for introducing a reforming material mixed with the raw fuel and the steam into the reformer;
A fuel cell system comprising: a heating means for heating at least the steam channel or at least the reforming material channel among the steam channel, the raw fuel channel and the reforming material channel. A reformer that reforms the raw fuel to generate a reformed gas, and is connected to the reformer via a reformed gas flow path and generates power using the reformed gas generated by the reformer. In a method of operating a fuel cell system comprising a fuel cell stack for performing
When starting up the fuel cell system, the temperature of at least one of the reformed gas channel, the gas channel in the fuel cell stack, and the downstream gas channel of the fuel cell stack is raised to a temperature equal to or higher than the boiling point of water. In this state, the reformed gas is supplied to the fuel cell stack. A reformer that reforms the raw fuel to generate a reformed gas, and is connected to the reformer via a reformed gas flow path and generates power using the reformed gas generated by the reformer. In a method of operating a fuel cell system comprising a fuel cell stack for performing
At least one of the reformed gas flow path, the gas flow path in the fuel cell stack, and the downstream gas flow path of the fuel cell stack is previously filled with a combustion catalyst,
When starting up the fuel cell system, the reformed gas is supplied to the fuel cell stack and air is supplied to the combustion catalyst, and the reformed gas channel, a gas channel in the fuel cell stack, and A method of operating a fuel cell system, wherein the temperature of at least one of the downstream gas flow paths is maintained at a temperature equal to or higher than the boiling point of water. A reformer that reforms the raw fuel to generate a reformed gas, and is connected to the reformer via a reformed gas flow path and generates power using the reformed gas generated by the reformer. In a method of operating a fuel cell system comprising a fuel cell stack for performing
When stopping the fuel cell system, at least one of the reformed gas channel, the gas channel in the fuel cell stack, and the downstream gas channel of the fuel cell stack is maintained at a temperature equal to or higher than the boiling point of water. The fuel cell system operating method is characterized in that the temperature of the fuel cell system is lowered and the supply of the reformed gas to the fuel cell stack is stopped in that state. A reformer that reforms the raw fuel to generate a reformed gas, a fuel cell stack that generates electric power using the reformed gas generated by the reformer, and a container that houses the fuel cell stack; In a method for operating a fuel cell system comprising:
When starting up the fuel cell system, the temperature of at least the bottom of the container is raised to a temperature equal to or higher than the boiling point of water, and the reformed gas is supplied to the fuel cell stack in that state. How to operate the system. A reformer that reforms the raw fuel to generate a reformed gas; a fuel cell stack that generates electric power using the reformed gas generated by the reformer; and a container that houses the fuel cell stack. In a method for operating a fuel cell system comprising:
When the fuel cell system is stopped, the temperature is lowered so that at least the bottom of the container is maintained at a temperature equal to or higher than the boiling point of water, and the supply of the reformed gas to the fuel cell stack is stopped in that state. A method for operating a fuel cell system. A reformer that reforms the raw fuel to generate reformed gas, a fuel cell stack that generates electric power using the reformed gas generated by the reformer, and steam to the reformer A steam channel for supplying, a raw fuel channel for supplying the raw fuel toward the reformer, the steam channel and the raw fuel channel, and being connected to the raw fuel and the steam In a method of operating a fuel cell system comprising a reforming material flow path for introducing a reforming material mixed with a reformer into the reformer,
When starting up the fuel cell system, the temperature of at least the water vapor channel of the water vapor channel, the raw fuel channel and the reforming raw material channel is raised to a temperature equal to or higher than the boiling point of water. A method for operating a fuel cell system, wherein water vapor and the raw fuel are sequentially supplied to the reformer. A reformer that reforms the raw fuel to generate reformed gas, a fuel cell stack that generates electric power using the reformed gas generated by the reformer, and steam to the reformer A steam channel for supplying, a raw fuel channel for supplying the raw fuel toward the reformer, the steam channel and the raw fuel channel, and being connected to the raw fuel and the steam In a method for operating a fuel cell system comprising a reforming material flow path for introducing a reforming material mixed with a reformer into the reformer,
When the fuel cell system is stopped, at least the steam channel among the steam channel, the raw fuel channel, and the reforming material channel is maintained at a temperature equal to or higher than the boiling point of water, and in this state, A method of operating a fuel cell system, wherein supply of fuel and water vapor is sequentially stopped. A reformer that reforms the raw fuel to generate reformed gas, a fuel cell stack that generates electric power using the reformed gas generated by the reformer, and steam to the reformer A steam channel for supplying, a raw fuel channel for supplying the raw fuel toward the reformer, the steam channel and the raw fuel channel, and being connected to the raw fuel and the steam In a method of operating a fuel cell system comprising a reforming material flow path for introducing a reforming material mixed with a reformer into the reformer,
When starting up the fuel cell system, at least the reforming material channel of the water vapor channel, the raw fuel channel, and the reforming material channel has a higher temperature of water and the boiling point of the raw fuel. A method of operating a fuel cell system, wherein the temperature is raised to the above temperature and the steam and the raw fuel are sequentially supplied to the reformer in that state. A reformer that reforms the raw fuel to generate reformed gas, a fuel cell stack that generates electric power using the reformed gas generated by the reformer, and steam to the reformer A steam path for supplying; a raw fuel path for supplying the raw fuel toward the reformer; the steam path and the raw fuel path; and the raw fuel and the steam In a method of operating a fuel cell system comprising a reforming material flow path for introducing a reforming material mixed with a reformer into the reformer,
When stopping the fuel cell system, at least the reforming raw material flow path among the water vapor flow path, the raw fuel flow path, and the reforming raw material flow path has a higher temperature of water and the boiling point of the raw fuel. The fuel cell system operating method is characterized in that the temperature is maintained at the above-described temperature and the supply of the raw fuel and the water vapor is sequentially stopped in this state.

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