WO2011036886A1 - Fuel cell system and operation method for fuel cell system - Google Patents

Fuel cell system and operation method for fuel cell system Download PDF

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Publication number
WO2011036886A1
WO2011036886A1 PCT/JP2010/005765 JP2010005765W WO2011036886A1 WO 2011036886 A1 WO2011036886 A1 WO 2011036886A1 JP 2010005765 W JP2010005765 W JP 2010005765W WO 2011036886 A1 WO2011036886 A1 WO 2011036886A1
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hydrogen
gas
fuel cell
control
reformer
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PCT/JP2010/005765
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French (fr)
Japanese (ja)
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可児幸宗
脇田英延
藤原誠二
中嶋知之
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パナソニック株式会社
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/04—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
    • H01M8/04223—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids during start-up or shut-down; Depolarisation or activation, e.g. purging; Means for short-circuiting defective fuel cells
    • H01M8/04228—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids during start-up or shut-down; Depolarisation or activation, e.g. purging; Means for short-circuiting defective fuel cells during shut-down
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/06—Combination of fuel cells with means for production of reactants or for treatment of residues
    • H01M8/0662—Treatment of gaseous reactants or gaseous residues, e.g. cleaning
    • H01M8/0668—Removal of carbon monoxide or carbon dioxide
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B3/00—Hydrogen; Gaseous mixtures containing hydrogen; Separation of hydrogen from mixtures containing it; Purification of hydrogen
    • C01B3/02—Production of hydrogen or of gaseous mixtures containing a substantial proportion of hydrogen
    • C01B3/32—Production of hydrogen or of gaseous mixtures containing a substantial proportion of hydrogen by reaction of gaseous or liquid organic compounds with gasifying agents, e.g. water, carbon dioxide, air
    • C01B3/34—Production of hydrogen or of gaseous mixtures containing a substantial proportion of hydrogen by reaction of gaseous or liquid organic compounds with gasifying agents, e.g. water, carbon dioxide, air by reaction of hydrocarbons with gasifying agents
    • C01B3/38—Production of hydrogen or of gaseous mixtures containing a substantial proportion of hydrogen by reaction of gaseous or liquid organic compounds with gasifying agents, e.g. water, carbon dioxide, air by reaction of hydrocarbons with gasifying agents using catalysts
    • C01B3/384—Production of hydrogen or of gaseous mixtures containing a substantial proportion of hydrogen by reaction of gaseous or liquid organic compounds with gasifying agents, e.g. water, carbon dioxide, air by reaction of hydrocarbons with gasifying agents using catalysts the catalyst being continuously externally heated
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B3/00—Hydrogen; Gaseous mixtures containing hydrogen; Separation of hydrogen from mixtures containing it; Purification of hydrogen
    • C01B3/02—Production of hydrogen or of gaseous mixtures containing a substantial proportion of hydrogen
    • C01B3/32—Production of hydrogen or of gaseous mixtures containing a substantial proportion of hydrogen by reaction of gaseous or liquid organic compounds with gasifying agents, e.g. water, carbon dioxide, air
    • C01B3/34—Production of hydrogen or of gaseous mixtures containing a substantial proportion of hydrogen by reaction of gaseous or liquid organic compounds with gasifying agents, e.g. water, carbon dioxide, air by reaction of hydrocarbons with gasifying agents
    • C01B3/48—Production of hydrogen or of gaseous mixtures containing a substantial proportion of hydrogen by reaction of gaseous or liquid organic compounds with gasifying agents, e.g. water, carbon dioxide, air by reaction of hydrocarbons with gasifying agents followed by reaction of water vapour with carbon monoxide
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/04—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
    • H01M8/04223—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids during start-up or shut-down; Depolarisation or activation, e.g. purging; Means for short-circuiting defective fuel cells
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/04—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
    • H01M8/04298—Processes for controlling fuel cells or fuel cell systems
    • H01M8/043—Processes for controlling fuel cells or fuel cell systems applied during specific periods
    • H01M8/04303—Processes for controlling fuel cells or fuel cell systems applied during specific periods applied during shut-down
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/04—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
    • H01M8/04298—Processes for controlling fuel cells or fuel cell systems
    • H01M8/04313—Processes for controlling fuel cells or fuel cell systems characterised by the detection or assessment of variables; characterised by the detection or assessment of failure or abnormal function
    • H01M8/0438—Pressure; Ambient pressure; Flow
    • H01M8/04425—Pressure; Ambient pressure; Flow at auxiliary devices, e.g. reformers, compressors, burners
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/04—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
    • H01M8/04298—Processes for controlling fuel cells or fuel cell systems
    • H01M8/04694—Processes for controlling fuel cells or fuel cell systems characterised by variables to be controlled
    • H01M8/04746—Pressure; Flow
    • H01M8/04776—Pressure; Flow at auxiliary devices, e.g. reformer, compressor, burner
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/06—Combination of fuel cells with means for production of reactants or for treatment of residues
    • H01M8/0606—Combination of fuel cells with means for production of reactants or for treatment of residues with means for production of gaseous reactants
    • H01M8/0612—Combination of fuel cells with means for production of reactants or for treatment of residues with means for production of gaseous reactants from carbon-containing material
    • H01M8/0618—Reforming processes, e.g. autothermal, partial oxidation or steam reforming
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B2203/00—Integrated processes for the production of hydrogen or synthesis gas
    • C01B2203/04—Integrated processes for the production of hydrogen or synthesis gas containing a purification step for the hydrogen or the synthesis gas
    • C01B2203/0435—Catalytic purification
    • C01B2203/044—Selective oxidation of carbon monoxide
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B2203/00—Integrated processes for the production of hydrogen or synthesis gas
    • C01B2203/04—Integrated processes for the production of hydrogen or synthesis gas containing a purification step for the hydrogen or the synthesis gas
    • C01B2203/0465—Composition of the impurity
    • C01B2203/047—Composition of the impurity the impurity being carbon monoxide
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B2203/00—Integrated processes for the production of hydrogen or synthesis gas
    • C01B2203/06—Integration with other chemical processes
    • C01B2203/066—Integration with other chemical processes with fuel cells
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B2203/00—Integrated processes for the production of hydrogen or synthesis gas
    • C01B2203/16—Controlling the process
    • C01B2203/1604—Starting up the process
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B2203/00—Integrated processes for the production of hydrogen or synthesis gas
    • C01B2203/16—Controlling the process
    • C01B2203/1609—Shutting down the process
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B2203/00—Integrated processes for the production of hydrogen or synthesis gas
    • C01B2203/16—Controlling the process
    • C01B2203/1614—Controlling the temperature
    • C01B2203/1619—Measuring the temperature
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B2203/00—Integrated processes for the production of hydrogen or synthesis gas
    • C01B2203/16—Controlling the process
    • C01B2203/1685—Control based on demand of downstream process
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/10—Fuel cells with solid electrolytes
    • H01M2008/1095—Fuel cells with polymeric electrolytes
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/30—Hydrogen technology
    • Y02E60/50—Fuel cells

Definitions

  • the present invention relates to a fuel cell system including a hydrogen generator that generates a hydrogen-containing gas from a fossil raw material and the like, and an operation method of the fuel cell system.
  • the hydrogen generator includes a reformer that reforms and reacts a raw material and water, a transformer that shifts a carbon monoxide and water vapor to a water gas in order to reduce the concentration of carbon monoxide derived from the raw material in hydrogen gas, and one
  • a structure is provided in which a CO remover that oxidizes carbon oxide mainly with an oxidizing gas such as a minute amount of air to further reduce carbon monoxide is provided.
  • a catalyst suitable for each reaction for example, a Ru catalyst or Ni catalyst is used for the reformer, a Cu-Zn catalyst is used for the shifter, a Ru catalyst is used for the CO remover, and the like. Yes.
  • Each reactor has a suitable temperature.
  • the reformer is often used at about 600 to 700 ° C., the reformer is used at about 350 to 200 ° C., and the CO remover is used at about 200 to 100 ° C.
  • the CO concentration in the supplied hydrogen-containing gas must be suppressed to several tens of volume ppm. Therefore, in the CO remover, the CO concentration is reduced by oxidizing the CO contained in the hydrogen-containing gas.
  • the CO remover can be heated by a heater provided in the CO remover or by continuing to supply air to the CO remover even after the operation is stopped.
  • the dew point in the downstream gas path is lowered to suppress dew condensation (see, for example, Patent Document 2).
  • the reformer having a relatively high control temperature can perform the purge operation during the generation operation of the hydrogen-containing gas.
  • the purge operation is not performed until the temperature is reduced to a proper temperature.
  • condensation may occur while the reformer is lowered to a purgeable temperature.
  • the heater provided in the CO remover is heated so as not to condense, but this reduces energy saving.
  • the present invention solves the above-described problem, and in the period until the purge operation is performed, a fuel cell system that suppresses dew condensation in a CO remover while improving energy saving performance more than the conventional one, and fuel It aims at providing the operating method of a battery system.
  • the fuel cell system of the present invention comprises: A reformer having a reforming catalyst that generates a hydrogen-containing gas using a raw material, a CO remover having an oxidation catalyst for reducing carbon monoxide contained in the hydrogen-containing gas by an oxidation reaction, and the CO removal
  • a fuel cell system comprising: a hydrogen generator comprising a first oxidant gas supplier for supplying an oxidant gas to the vessel; a fuel cell for generating electricity using the hydrogen-containing gas supplied from the hydrogen generator; and a controller Because The controller is When stopping the power generation operation of the fuel cell system, (i) Prior to the stop, the operating amount of the oxidizing gas supplier is controlled so that the supply amount of the oxidizing gas with respect to the supply amount of the hydrogen-containing gas to the CO remover is larger than that during the power generation operation.
  • the operating method of the fuel cell system of the present invention includes a reformer having a reforming catalyst for generating a hydrogen-containing gas using raw materials, and reducing carbon monoxide contained in the hydrogen-containing gas by an oxidation reaction.
  • a hydrogen generator comprising a CO remover having an oxidation catalyst, a first oxidizing gas supplier for supplying an oxidizing gas to the CO remover, and a hydrogen-containing gas supplied from the hydrogen generator to generate power.
  • An operation method of a fuel cell system comprising a fuel cell to perform, When stopping the power generation operation of the fuel cell system, (i) Prior to the stop, the operating amount of the oxidizing gas supplier is controlled so that the supply amount of the oxidizing gas with respect to the supply amount of the hydrogen-containing gas to the CO remover is larger than that during the power generation operation. 1 control, and (ii) In the period in which the hydrogen-containing gas is sent from the reformer after the stop, the supply amount of the oxidizing gas with respect to the supply amount of the hydrogen-containing gas to the CO remover is larger than that during power generation operation. Performing at least one of the second control for controlling the operation amount of the oxidizing gas supply device, A purge operation in the hydrogen generator is performed after at least one of the first control and the second control is performed.
  • a fuel cell system and a fuel cell system operation method that suppress dew condensation in a CO remover while improving energy saving performance over the period until a purge operation is performed. Can do.
  • a fuel cell system includes a reformer having a reforming catalyst that generates a hydrogen-containing gas using raw materials, and a method for reducing carbon monoxide contained in the hydrogen-containing gas by an oxidation reaction.
  • a hydrogen generator comprising a CO eliminator having an oxidation catalyst, a first oxidant gas supplier for supplying an oxidant gas to the CO eliminator, and a fuel cell for generating electricity using a hydrogen-containing gas supplied from the hydrogen generator
  • a controller when the controller stops the power generation operation of the fuel cell system, (i) the supply amount of the hydrogen-containing gas to the CO remover prior to the stop And (ii) a period in which the hydrogen-containing gas is sent from the reformer after being stopped.
  • a purge operation in the hydrogen generator is performed after performing at least one of the above control and the second control.
  • the operation method of the fuel cell system includes a reformer having a reforming catalyst that generates a hydrogen-containing gas using raw materials, and an oxidation reaction of carbon monoxide contained in the hydrogen-containing gas.
  • a hydrogen generator having a CO remover having an oxidation catalyst for reducing the gas
  • a first oxidizing gas supplier for supplying an oxidizing gas to the CO remover
  • a hydrogen-containing gas supplied from the hydrogen generator An operation method of a fuel cell system including a fuel cell that generates power, and when stopping the power generation operation of the fuel cell system, (i) the amount of hydrogen-containing gas supplied to the CO remover prior to the stop And (ii) a period in which the hydrogen-containing gas is sent from the reformer after being stopped.
  • a purge operation in the hydrogen generator is performed after performing at least one of the first control and the second control.
  • the operation amount of the oxidant gas supply device may be increased during the entire period in which the hydrogen-containing gas is sent from the reformer, or the hydrogen-containing gas is supplied from the reformer.
  • the oxidant gas supply may be controlled to increase the amount of operation of the oxidant gas supply only during a portion of the delivery period.
  • the purge operation is defined as an operation in which a gas remaining in the hydrogen generator is replaced with a gas having a composition different from that of the residual gas (excluding water vapor). Examples thereof include active gas, air, and raw material gas.
  • “prior to stop” means that the controller precedes at least one of the devices operating during the power generation operation to output a stop command to stop the power generation operation. is there.
  • after stop means that the controller has output a stop command to stop the power generation operation to at least one of the devices operating during the power generation operation.
  • Embodiment 1 In the fuel cell system according to Embodiment 1, when the controller stops the power generation operation of the fuel cell system, the supply amount of the oxidizing gas with respect to the supply amount of the hydrogen-containing gas to the CO remover prior to the stoppage. However, the first control for controlling the operation amount of the oxidizing gas supply unit is performed so as to be larger than that during the power generation operation, and the purge operation in the hydrogen generator is performed after the first control is performed.
  • the supply of the oxidizing gas with respect to the supply amount of the hydrogen-containing gas to the CO remover prior to the stop The first control for controlling the operation amount of the oxidizing gas supplier is executed so that the amount becomes larger than that during the power generation operation, and the purge operation in the hydrogen generator is executed after the first control is executed.
  • FIG. 1 is a configuration diagram of the fuel cell system according to the first embodiment.
  • the fuel cell system according to the present embodiment includes a hydrogen generator 1 and a fuel cell 100.
  • This hydrogen generation apparatus 1 mainly proceeds with a reforming reaction of a raw material containing an organic compound composed of at least carbon and hydrogen, such as city gas mainly composed of methane, natural gas, hydrocarbons such as LPG, and steam. To generate a hydrogen-containing gas.
  • the fuel cell 100 uses the hydrogen-containing gas supplied from the hydrogen generator 1 as an anode gas, and uses an oxidant gas such as air supplied from a cathode gas supplier 110 as a cathode gas, and causes both to react. It is a device that generates electricity.
  • the reforming reaction may be any type of reforming reaction as long as it is a reforming reaction using a raw material and steam.
  • a steam reforming reaction or an autothermal reaction is adopted.
  • the fuel cell may be any type of fuel cell, such as a polymer electrolyte fuel cell, a phosphoric acid fuel cell, or a solid oxide fuel cell.
  • the hydrogen generator 1 of the present embodiment is provided with a hydrogen generator 8 that generates a hydrogen-containing gas from a raw material and water vapor.
  • the hydrogen generator 8 is configured to selectively oxidize carbon monoxide in the hydrogen-containing gas generated by the reformer 14 that progresses the reforming reaction using the raw material and steam and the reformer 14.
  • a CO eliminator 15 is provided to reduce the amount.
  • an oxidizing gas supply unit 23 is provided for supplying air used for oxidation in the CO remover 15 to the hydrogen-containing gas discharged from the reformer 14.
  • the reformer 14 is provided with a Ni-based reforming catalyst, and the CO remover 15 is provided with a Ru-based selective oxidation catalyst.
  • a combustor 2 that generates heat for causing the reforming reaction in the reformer 14 to proceed is provided. Further, an igniter 21 that is an ignition source of the combustor 2, a frame rod 22 that detects a combustion state of the combustor 2, and an air supply device 20 that supplies combustion air to the combustor 2 are provided.
  • the combustion gas that serves as a heating source for the combustor 2 a raw material that has passed through the hydrogen generator 8, an anode off-gas discharged from the anode of the fuel cell 100, and the like are used.
  • a water supply device 3 that is a pump for supplying water to the reformer 14 and a raw material supply device 4 for supplying raw materials to the reformer 14 are provided.
  • the raw material supplier 4 is a booster pump, and is configured to control the flow rate by controlling, for example, input current pulses and input power.
  • the water supply device 3 is a pump having a flow rate adjusting function similarly to the raw material supply device 4.
  • the gas infrastructure 6 is used as a raw material supply source.
  • An adsorbing desulfurizer 5 filled with an adsorbing desulfurizing agent is connected to the gas infrastructure line 6, and the adsorbing desulfurizer 5 is connected to the raw material supplier 4.
  • a hydrogen gas supply path 9 for supplying the hydrogen-containing gas generated by the hydrogen generator 8 to the fuel cell 100 is provided.
  • an anode off-gas supply path 10 is provided for supplying the hydrogen-containing gas that has not been consumed by the fuel cell 100 to the combustor 2.
  • a bypass path 12 that bypasses the fuel cell 100 and connects the hydrogen gas supply path 9 and the anode off-gas supply path 10 is provided.
  • the bypass path 12 is provided with an open / close valve 11a, and an open / close valve 11b is provided downstream of the branch point of the hydrogen gas supply path 9 to the bypass path 12 (see P in FIG. 1).
  • the junction of the bypass path 12 to the anode off gas supply path 10 is indicated by Q in FIG.
  • the reformer 14 and the CO remover 15 are provided with a reforming temperature detector 24 and a selective oxidation temperature detector 25 in order to detect respective catalyst temperatures.
  • a thermocouple, a thermistor, or the like is used as each detector.
  • a controller 13 for controlling the amount, the air supply device 20, the on-off valves 11a and 11b, the igniter 21 and the like is provided (see FIG. 1).
  • the controller 13 includes an arithmetic processing unit and a storage unit that stores a control program for executing at least one of the first control and the second control.
  • the arithmetic processing unit is configured by, for example, a microprocessor, a CPU, and the like, and the storage unit is configured by a semiconductor memory or the like. Further, the controller 13 includes either a single controller or a plurality of distributed controllers that cooperate to control the fuel cell system.
  • the raw material is supplied from the raw material supplier 4 to the hydrogen generator 8 according to a command from the controller 13.
  • the on-off valve 11 a is in the open state and the on-off valve 11 b is in the closed state, and the raw material discharged from the hydrogen generator 8 is supplied to the combustor 2 via the bypass path 12.
  • the raw material is used as fuel and ignited in the combustor 2 to start heating.
  • the controller 13 operates the water supply device 3 so that water is supplied to the reformer 14 and the water And the reforming reaction of the raw material is started.
  • the city gas (13A) which has methane as a main component is used as a raw material.
  • the amount of water supplied is such that about 3 mol of water vapor is present per 1 mol of carbon atoms in the average molecular formula of the supplied city gas (steam carbon ratio (S / C) is about 3).
  • Air is supplied to the CO remover 15 from the oxidizing gas supply unit 23 so that the CO / O 2 molar ratio is about 2 to 3.
  • the reformer 14 and the CO remover 15 are warmed, and the steam reforming reaction and the selective oxidation reaction proceed.
  • the on-off valve 11a is closed and the on-off valve 11b is opened so that the flow path of the gas discharged from the hydrogen generator 8 becomes the fuel cell 100.
  • the hydrogen-containing gas is supplied from the hydrogen gas supply path 9 to the fuel cell 100.
  • power generation is performed using the air supplied from the cathode gas supply unit 110 and the hydrogen-containing gas.
  • the steam reforming reaction is an endothermic reaction
  • the selective oxidation reaction is an exothermic reaction.
  • the temperature of the reformer 14 during power generation is about 400 to 650 ° C.
  • the temperature of the CO remover 15 is 120 to 160 ° C.
  • the temperature detected by the reforming temperature detector 24 is about 650 ° C.
  • the temperature detected by the selective oxidation temperature detector 25 is about 160 ° C.
  • the controller 13 When the controller 13 outputs a stop command for stopping the operation of the fuel cell system, the cathode gas supply device 110 is stopped and the operation of the hydrogen generator 1 is also stopped.
  • the hydrogen-containing gas expelled by the raw material gas is supplied to the combustor 2.
  • the temperature of the reformer 14 rises due to heating of the combustor 2, which may cause carbon deposition. Therefore, it is desirable to perform the purge at the lowest possible temperature in anticipation of the temperature rise of the reformer 14 by the combustor 2.
  • there is a method of diluting and exhausting the hydrogen-containing gas scavenged from the hydrogen generator in the purge operation without burning it with air or the like it is desirable to burn it from the viewpoint of effective use of energy.
  • the characteristic operation in the present embodiment is that the controller 13 performs the following operation before stopping the power generation of such a fuel cell system.
  • FIG. 2 is a diagram showing a control flow of the stopping method of the fuel cell system according to the first embodiment.
  • step is abbreviated as S.
  • S step
  • the controller determines that the power generation operation is stopped due to a decrease in power demand, or when the user stops the power generation of the fuel cell system via an operating device (for example, a remote controller). Is required.
  • step 1 the controller 13 determines a time H1 at which a stop command is issued.
  • step 2 it is determined whether or not the remaining operating time (time H1 ⁇ current time t) until the timing of issuing the stop command is less than a preset time H0, and the remaining time until the power generation stops. Falls below the preset time H0, the control shifts to step 3. Specifically, for example, when H1 is 23:20, 20 minutes after the current time, and H0 is 10 minutes, when time t exceeds 23:10, H1-t becomes smaller than H0. Therefore, the control proceeds to step 3.
  • step 3 the controller 13 issues an instruction to control the operation amount of the oxidizing gas supply device 23 so that the temperature of the selective oxidation catalyst becomes higher than the control temperature during the power generation operation. Specifically, control is performed such that the operating amount of the oxidizing gas supply device 23 is increased from the immediately preceding operating amount so that the temperature of the selective oxidation catalyst becomes higher than the control temperature during power generation operation.
  • the operation amount of the oxidizing gas supplier 23 is controlled so that the supply amount of the oxidizing gas (air) with respect to the supply amount of the hydrogen-containing gas to the CO remover 15 is larger than that during the power generation operation.
  • the amount of oxidation reaction between hydrogen in the hydrogen-containing gas flowing through the CO remover 15 and oxygen in the air increases, and the temperature of the selective oxidation catalyst is controlled during power generation operation due to heat generated by the oxidation reaction. It becomes higher than the temperature.
  • step 4 it is determined whether or not it is time to issue a system stop command. That is, it is determined whether or not the current time t has exceeded H1.
  • the stop command timing is not exceeded (when t ⁇ H1), the state in which the amount of air supplied from the oxidizing gas supplier 23 is increased until the stop command timing H1 is exceeded.
  • step 5 When the current time t exceeds the stop command timing (t> H1), the control shifts to step 5 and the controller 13 issues a stop command.
  • the controller 13 opens the on-off valve 11a and closes the on-off valve 11b. By switching the on-off valves 11 a and 11 b in this way, the gas discharged from the hydrogen generator 8 is not supplied to the fuel cell 100 but is sent to the combustor 2 via the bypass path 12.
  • Step 7 the operation of the cathode gas supply device 110 is also stopped, and the power generation in the fuel cell 100 is stopped. Further, the controller 13 performs control to stop the water supplier 3, the raw material supplier 4, and the oxidizing gas supplier 23, and the steam reforming reaction is stopped.
  • step 8 when the reforming detection temperature TK reaches the raw material supply start temperature T1, the control proceeds to step 9, and the raw material supplier 4 operates to perform the raw material purge.
  • the gas discharged from the hydrogen generator 8 is supplied to the fuel cell 100 side by performing control to close the on-off valve 11a and open the on-off valve 11b. The inside may be purged with the source gas. Further, as described above, in consideration of the temperature rise of the reformer 14 due to the combustion of the raw material gas in the combustor 2, the raw material supply start temperature T1 is set low.
  • the raw material supplier 4 is stopped in step 10.
  • the operation amount of the oxidizing gas supply 23 is set before the stop command so that the temperature of the oxidation catalyst becomes higher than the control temperature during the power generation operation. Control is performed. Therefore, it is possible to suppress the occurrence of condensation until the reforming detection temperature TK reaches T1 while improving the energy saving performance as compared with the conventional fuel cell system.
  • the CO remover 15 is set so that the temperature in the CO remover 15 does not reach the dew condensation temperature.
  • the time H1 at which the stop command is issued is determined, the difference from the current time t is obtained, and if the difference becomes smaller than H0, the oxidation is performed.
  • the oxidizing gas supplier 23 immediately follows the trigger for executing the control flow without determining the time H1 at which the stop command is issued. Control for increasing the supply amount of air may be performed. That is, any form may be used as long as the control for increasing the operation amount of the oxidizing gas supply unit 23 is executed prior to the stop of power generation in the fuel cell system.
  • Embodiment 2 In the fuel cell system according to Embodiment 2, when the controller stops the power generation operation of the fuel cell system, hydrogen is supplied to the CO remover during the period in which the hydrogen-containing gas is sent from the reformer after the stop.
  • the second generation control for controlling the operation amount of the oxidizing gas supply unit is executed so that the supply amount of the oxidizing gas with respect to the supply amount of the contained gas is larger than that during the power generation operation.
  • the purge operation is executed.
  • the hydrogen-containing gas is sent from the reformer to the CO remover.
  • the second control for controlling the operation amount of the oxidizing gas supply unit is executed so that the supply amount of the oxidizing gas with respect to the supply amount of the hydrogen-containing gas is larger than that during the power generation operation, and hydrogen is generated after the second control is executed.
  • a purge operation in the apparatus is executed.
  • the hydrogen-containing gas is sent from the reformer.
  • the reaction gas supply device is stopped, the hydrogen-containing gas generated from the reaction gas remaining in the reformer is supplied to the CO remover. Includes the time period to be sent.
  • the reaction gas supply device is a device that supplies a reaction gas used for the reforming reaction to the reformer. Specifically, the reaction gas supply device supplies a raw material to the reformer and supplies water to the reformer. A water supply device for supplying water.
  • the reactive gas supply device may include an oxidizing gas supply device.
  • the fuel cell system according to Embodiment 2 includes a combustor for heating the reformer, a combustion detector for detecting combustion in the combustor, and a gas sent from the CO remover flows into the combustor.
  • a period during which combustion of the combustor is detected by the combustion detector may be included.
  • combustion is detected by the combustion detector, so that it is possible to execute an increase control of the operation amount of the oxidant gas supply device at an appropriate timing. I can do it.
  • FIG. 3 is a diagram showing a control flow when the fuel cell system according to Embodiment 2 is stopped.
  • the controller 13 when the controller determines that the power generation operation is stopped due to a decrease in power demand, or when the user generates power from the fuel cell system via an operating device (for example, a remote controller).
  • the controller 13 first issues a stop command to each device constituting the fuel cell system (see step 20). With this stop command, stop control of the power generation operation of the fuel cell 100 and the operation of the hydrogen generator 1 is started.
  • step 21 the controller 13 opens the on-off valve 11a and closes the on-off valve 11b.
  • step 22 the operations of the water supply device 3, the cathode gas supply device 110, and the raw material supply device 4 are stopped.
  • step 23 an instruction is issued from the controller 13 to control the operation amount of the oxidizing gas supply device 23 so that the temperature of the selective oxidation catalyst becomes higher than the control temperature during the power generation operation. And control is performed so that the operation amount of the oxidizing gas supply device 23 increases from the operation amount immediately before the stop command.
  • the operation amount of the oxidizing gas supply unit 23 is controlled so that the supply amount of the oxidizing gas with respect to the supply amount of the hydrogen-containing gas to the CO remover 15 is larger than that during the power generation operation.
  • step 24 the state in which the operation amount of the oxidizing gas supply device 23 is increased is maintained.
  • the supply of the raw material and water is stopped in step 22, but the raw material and water vapor remain inside the reformer 14, and the reforming reaction proceeds with the remaining raw material and water vapor.
  • a hydrogen-containing gas containing carbon monoxide is generated.
  • the hydrogen-containing gas in the hydrogen generator 8 is sent from the hydrogen generator 8 as the water remaining in the reformer 14 evaporates.
  • the hydrogen-containing gas delivered from the hydrogen generator 8 is supplied to the combustor 2 via the bypass path 12 and burned. When the hydrogen-containing gas from the hydrogen generator 8 is no longer supplied to the combustor 2, the fire is extinguished.
  • the hydrogen-containing gas is supplied from the reformer 14 to the CO remover 15, and an exothermic reaction is caused by the air supplied by the oxidizing gas supplier 23.
  • the selective oxidation reaction of CO and the oxidation reaction of hydrogen proceed.
  • step 24 when fire extinguishing is detected in step 24, the controller 13 stops the operation of the oxidizing gas supplier 23 in step 25.
  • step 27 the raw material supplier 4 is operated, and the raw material purge is executed.
  • the raw material supplier 4 is stopped in step 28.
  • the temperature of the selective oxidation catalyst is changed to the power generation operation.
  • the operation amount of the oxidizing gas supply device 23 so as to be higher than the control temperature at the time, the amount of oxidation reaction with hydrogen increases, and the temperature of the CO remover 15 can be raised to a temperature higher than that during power generation operation. I can do it. Therefore, it is possible to suppress the occurrence of dew condensation in the CO remover 15 while the reforming detection temperature TK is lowered to the temperature (T1) at which the raw material can be purged.
  • gas flow path is the flow path from the CO remover 15 of the hydrogen gas supply path 9 to the branch point P to the bypass path 12, the bypass path 12, and the anode off-gas supply path 10 in the above embodiment. This corresponds to the flow path from the confluence point Q from the bypass path 12 to the combustor 2.
  • An example of the combustion detector corresponds to the frame rod 22.
  • the hydrogen-containing gas generated by the remaining raw material and water is circulated after the water supply device 3 and the raw material supply device 4 are stopped.
  • control was performed such that the operation amount of the oxidizing gas supply device 23 was increased from immediately before the stop command so that the temperature of the selective oxidation catalyst became higher than the control temperature during the power generation operation.
  • the control is not limited to such control, and may be control as shown in Modification 1 below.
  • after the power generation of the fuel cell system is stopped it is selected during the period in which the hydrogen-containing gas is sent from the reformer. It is only necessary to control the amount of operation of the oxidizing gas supplier so that the temperature of the oxidation catalyst becomes higher than the control temperature during the power generation operation.
  • the period in which the hydrogen-containing gas is sent from the reformer after the stop includes a period in which the supply of the reaction gas from the reaction gas supplier is continued even after the stop. It is characterized by.
  • the time during which the supply of the hydrogen-containing gas from the reformer to the CO remover is continued is longer than in the fuel cell system of Embodiment 2, so that the temperature of the CO remover can be further increased. . Accordingly, it is possible to suppress the occurrence of dew condensation due to the temperature of the CO remover being lowered before the reformer reaches a temperature at which the raw material can be purged, as compared with the fuel cell system of the second embodiment.
  • the operation amount of the oxidizing gas supply unit 23 is increased after the water supply unit 3 and the raw material supply unit 4 are stopped.
  • the oxidizing gas is supplied while continuing the water supply and the raw material supply. Control is performed so as to increase the operation amount of the feeder 23.
  • FIG. 4 is a diagram showing a control flow in this case.
  • the cathode gas supply device 110 is stopped and the supply amount of the water supply device 3 and the raw material supply device 4 starts to decrease.
  • Step 201 is provided.
  • the oxidizing gas supply device 23 is controlled in step 23, and the amount of oxidizing gas (air) supplied increases from immediately before the stop command.
  • step 202 the operations of the water supply unit 3 and the raw material supply unit 4 are stopped.
  • the fire extinguishing of the combustor 2 is detected in step 24 as in the second embodiment.
  • step 25 the oxidizing gas supply unit 23 is stopped.
  • step 26 when the reforming detection temperature TK reaches T1 in step 26, the raw material purge is performed in step 27 as described above. When the material purge is sufficiently performed, the material supply unit 4 is stopped in step 28.
  • the operation amount of the water supply device 3 and the raw material supply device 4 is gradually decreased and stopped in step 202, but the control is performed in step S202. Until the operation amount is not reduced, control may be performed so as to stop the operations of the water supply unit 3 and the raw material supply unit 4 in step 202.
  • the control flow in this case is shown in FIG.
  • step 220 is provided instead of step 201 shown in FIG. In this step 220, only the operation of the cathode gas supplier 110 is stopped.
  • step 23 the operation amount of the oxidizing gas supply device 23 is increased, for example, immediately before the stop command (during power generation operation) so that the temperature of the selective oxidation catalyst becomes higher than the control temperature during power generation operation.
  • the water supply unit 3 and the raw material supply unit 4 are stopped in step 202.
  • the predetermined time from step 23 to step 202 can be set, for example, as H0 in the first embodiment.
  • Modification 2 In the first embodiment, as an example of the first control, the operation amount of the oxidizing gas supplier 23 is controlled before the stop command so that the temperature of the selective oxidation catalyst becomes higher than the control temperature during the power generation operation. Thus, the temperature of the CO remover 15 is increased.
  • the temperature of the selective oxidation catalyst is higher than the control temperature while the hydrogen-containing gas containing carbon monoxide is flowing after the stop command. Thus, the temperature of the CO remover 15 is raised by controlling the operation amount of the oxidizing gas supply device 23.
  • the operation amount of the oxidizing gas supplier 23 is increased before and after the stop command so that the temperature of the selective oxidation catalyst becomes higher than the control temperature during the power generation operation. Control may be performed as described above.
  • FIG. 6 is a control flow diagram of Modification 2. Steps 211 to 216 shown in FIG. 6 are the same as steps 1 to 6 in the first embodiment. Then, after Step 216, in Modification 2, unlike Step 1, in Step 217, the operation of the oxidizing gas supplier 23 is not stopped and the state in which the operation amount of the oxidizing gas supplier 23 is increased is maintained. Then, the operations of the water supply unit 3, the raw material supply unit 4 and the cathode gas supply unit 110 are stopped.
  • step 218 when the discharge of the hydrogen-containing gas remaining in the hydrogen generator 8 is completed, and the fire extinguishing of the combustor 2 is detected in step 218, the operation of the oxidizing gas supply device 23 is stopped in step 219. Is done.
  • step 2221 the raw material purge is executed in step 221.
  • the operation of the material supplier 4 is stopped in step 222.
  • step 217 the water supply device 3 and the raw material supply device 4 are stopped in step 217.
  • the operation amounts of the water supply device 3 and the raw material supply device 4 are changed. Control may be performed so as to gradually decrease and stop. This control will be described with reference to FIG. 6.
  • step 217 the control is performed so that the operation amount of the water supply unit 3 and the raw material supply unit 4 is reduced as the cathode gas supply unit 110 is stopped. Thereafter, the water supply device 3 and the raw material supply device 4 are completely stopped, and when the fire extinguishing of the combustor 2 is detected in step 218, the oxidizing gas supply device 23 is stopped.
  • the hydrogen-containing gas is delivered from the reaction gas remaining in the reformer after the reaction gas supply device is stopped as a period for sending the hydrogen-containing gas from the reformer.
  • a period in which the reaction gas supply from the reaction gas supply device is continued when a combustion detector includes a period in which combustion of the combustor is detected, including a period during which the hydrogen-containing gas is delivered to the CO remover
  • the amount of operation of the oxidant gas supply device 23 is increased and until the fire extinguishing of the combustor 2 is detected (that is, the reformer 14 supplies hydrogen.
  • the increased amount of operation is maintained until the contained gas is no longer delivered.
  • the increase control of the operation amount of the oxidizing gas supply unit 23 may be stopped before the hydrogen-containing gas is not sent from the reformer 14. In this way, control for increasing the operation amount of the oxidizing gas supply device 23 may be performed in at least a part of the period in which the hydrogen-containing gas is sent from the reformer 14.
  • Embodiment 2 and Modifications 1 and 2 when the fire extinguishing of the combustor 2 is detected (that is, when the hydrogen-containing gas is no longer sent from the reformer 14), the oxidizing gas supply device 23 is stopped. However, it does not have to be stopped. However, if air is supplied from the oxidizing gas supply unit 23 even after the flow of the hydrogen-containing gas into the CO remover 15 is stopped, the amount of the oxidation reaction is reduced, and the cooling effect by the supply air further increases the temperature by the exothermic reaction. Since the temperature effect may be reduced, it is preferable to stop the oxidant gas supply device 23 when extinguishing the combustor 2 is detected.
  • the basic configuration of the fuel cell system of the third embodiment is the same as that of the fuel cell system of the first embodiment, but unlike the first embodiment, the CO remover 15 is provided with a heater. Therefore, this difference will be mainly described.
  • symbol is attached
  • FIG. 7 is a configuration diagram of the fuel cell system according to the third embodiment.
  • the fuel cell system of Embodiment 3 is provided with a heater 31 for heating the CO remover 15.
  • a controller 30 is also provided that also controls the heater 31 on and off based on the temperature detected by the selective oxidation temperature detector 25.
  • FIG. 8 is a diagram showing a control flow of the fuel cell system stopping method of the third embodiment. As shown in FIG. 8, in the third embodiment, if the reforming detection temperature TK does not reach T1 in step 8, the control proceeds to step 31. In addition, the same code
  • FIG. 8 is a diagram showing a control flow of the fuel cell system stopping method of the third embodiment. As shown in FIG. 8, in the third embodiment, if the reforming detection temperature TK does not reach T1 in step 8, the control proceeds to step 31. In addition, the same code
  • step 31 it is determined whether or not the selective oxidation detection temperature TS detected by the selective oxidation temperature detector 25 is higher than a preset temperature T2.
  • the controller 30 performs control so that the heater 31 is turned on in step 32.
  • the temperature T2 is set higher than the dew condensation occurrence temperature in consideration of the responsiveness of the heater 31.
  • step 33 when the selective oxidation detection temperature TS is higher than the set temperature T2 in step 31, the control proceeds to step 33, and the control is performed so that the heater 31 is turned off. After steps 32 and 33, control returns to step 8, and steps 31, 32, and 33 are repeated until the reforming detection temperature TK reaches T1. Then, when the temperature of the reforming detection temperature TK decreases to T1, the raw material purge is performed in Step 9. When the heater 31 is on, the raw material is purged at step 9 and is turned off.
  • the heater 31 is controlled until the reforming detection temperature TK reaches the temperature T1 at which the raw material can be purged, so that the temperature of the CO remover 15 does not fall below the dew condensation temperature. Therefore, it is possible to further suppress the occurrence of condensation in the CO remover 15 as compared with the fuel cell systems in the first and second embodiments and the respective modifications.
  • Example 1 In the control flow of the stopping method of the fuel cell system of FIG. 8, the stopping process of the fuel cell system was performed by assembling a program in which T1 was set to 150 ° C., T2 was set to 120 ° C., and H0 was set to 10 minutes.
  • FIG. 9 is a graph showing changes over time in the reforming detection temperature TK and the selective oxidation detection temperature TS.
  • the operation amount of the oxidizing gas supplier 23 is set to the operation amount immediately before so that the temperature of the selective oxidation catalyst becomes higher than the control temperature during the power generation operation. Therefore, the selective oxidation reaction, which is an exothermic reaction, was promoted, and the temperature of the CO remover 15 rose to about 200 ° C.
  • the temperatures of the reformer 14 and the CO remover 15 are lowered.
  • the temperature of the CO remover 15 decreased to 120 ° C., and the ON / OFF control of the heater 31 was started.
  • the heater 31 was ON-OFF controlled for 1 hour 55 minutes before starting the material purge, and the amount of power consumed by the heater was 587.5 Wh.
  • the increase in the supply amount of the oxidizing gas (air) during 10 minutes when the air supply amount of the oxidizing gas supply unit 23 was increased was 4 NL. If the oxygen concentration in the atmosphere is 21%, the amount of consumed hydrogen is 0.84 NL, which corresponds to 21.3 kJ as the amount of combustion heat. Since 1 Wh is 3.2 kJ, the amount of combustion heat is equivalent to 5.9 Wh.
  • FIG. 10 is a graph showing a temporal change graph of the reforming detection temperature TK and the selective oxidation detection temperature TS.
  • the heater 31 was ON-OFF controlled for 2 hours and 5 minutes before starting the raw material purge, and the amount of power consumed by the heater 31 was 612.5 Wh.
  • control of the heater 31 is added to the first control described in the first embodiment, but instead of the first control, as described in the second embodiment and the first modification.
  • the control of the heater 31 may be added to the second control.
  • the control of the heater 31 may be added to the control that performs both the first control and the second control as described in the second modification of the second embodiment.
  • the hydrogen generator 8 in the first to third embodiments is provided with the reformer 14 and the CO remover 15. However, a shift reaction takes place between the reformer 14 and the CO remover 15.
  • a transformer may be provided. In this transformer, the shift reaction takes place at about 150-300 ° C.
  • the transformer may also be provided with a heater like the CO remover 15 of the third embodiment. This heater may be integrated with the heater of the CO remover 15 or may be provided separately.
  • on-off valve corresponds to the on-off valve 11a and the on-off valve 11b of the above embodiment, but instead of providing two on-off valves, three points are provided at the branch point P of the hydrogen gas supply path 9 to the bypass path 12. It is good also as a structure provided with the valve. In short, it is only necessary to switch the supply destination of the gas discharged from the hydrogen generator 8 to either the fuel cell 100 side or the bypass path 12 side.
  • the selective oxidation temperature detector 25 is provided, and the control temperature of the oxidation catalyst is higher than the control temperature during the power generation operation while checking the detected temperature.
  • the operation amount of the oxidizing gas supply device 23 is increased so as to be higher.
  • the present invention is not limited to this embodiment, and the oxidizing gas supply amount with respect to the hydrogen-containing gas supply amount to the CO remover is oxidized so as to be larger than that in the power generation operation without providing the selective oxidation temperature detector 25.
  • the operation amount of the gas supply device 23 may be controlled.
  • the operation amount of the oxidizing gas supply unit 23 is controlled so that the supply amount of the oxidizing gas with respect to the physical quantity proportional to the supply amount of the hydrogen-containing gas to the CO remover 15 increases.
  • the physical quantity include a raw material supply amount to the reformer 14, a water vapor supply amount to the reformer 14, and a power generation amount of the fuel cell system.
  • any configuration is possible as long as the operation amount of the oxidant gas supply unit 23 is controlled so that the supply amount of the oxidant gas relative to the hydrogen-containing gas supply amount to the CO remover 15 is larger than that during power generation operation. It does not matter.
  • the fuel cell system according to Embodiments 1 to 3 and the modification thereof employs a mode in which the oxidizing gas supply device 23 operates continuously during the increase control of the operation amount of the oxidizing gas supply device 23.
  • a mode that operates intermittently may be adopted.
  • the on-off valve 11a is opened and the on-off valve 11b is closed.
  • the step of stopping the water supply device 3 and the raw material supply device 4 is provided, but the order may be reversed, and these steps may be performed simultaneously. These steps correspond to Step 6 and Step 7 when described with reference to FIG. 2 of the first embodiment.
  • combustion is performed in the combustor 2 at the time of stop control, but the combustion may not be performed. However, since it is desirable to dilute the raw material gas from the fuel cell system, it is preferable to operate the air supply unit 20 of the combustor 2.
  • the amount of oxidizing gas supplied by the oxidizing gas supplier 23 is always increased.
  • T3 a predetermined temperature
  • a control flow may be configured to return the oxidizing gas supply amount to the state before the increase. Good.
  • FIG. 11 is a flowchart showing such control.
  • step 34 for determining TS ⁇ T3 is inserted between step 2 and step 3 of the control flow of FIG. 2, and if TS is less than T3, control goes to step 3
  • control is performed so as to increase the operation amount of the oxidizing gas supply unit 23. More specifically, the supply amount of the oxidizing gas with respect to the supply amount of the hydrogen-containing gas to the CO remover 15 is started before the increase control of the operation amount of the oxidizing gas supply device 23 is started (before Yes in Step 2).
  • the operating amount of the oxidizing gas supply device is controlled so as to increase the amount.
  • the operation amount becomes the operation amount before the increase control of the operation amount of the oxidizing gas supply device 23 is started in step 35 (before becoming Yes in step 2).
  • the oxidizing gas supplier 23 is controlled, and the process returns to step 34, and this state is continued until TS becomes less than T3.
  • the state in which the operation amount is increased is maintained in Step 3. Become.
  • This T3 can be set to 200 ° C., for example.
  • the control using the T3 is applied to H0 that is the period during which the operation amount is increased.
  • T3 is used for the period from when the controller 13 outputs a stop command until the combustor 2 is detected for digestion. You may apply the control you had.
  • the control of increasing the operation amount of the oxidizing gas supplier is started prior to the stop of power generation of the fuel cell system (Yes in step 2).
  • the control using T3 may be applied to the period until the combustor 2 is detected for digestion.
  • the supply amount of the oxidizing gas (air) is increased.
  • an upper limit may be set for the supply amount of the oxidizing gas (air). If a selective oxidation upper limit temperature is separately provided at a temperature lower than the thermal runaway start temperature, and the selective oxidation detection temperature exceeds the upper limit temperature, thermal runaway may be caused by reducing the supply amount of oxidizing gas (air). Can be prevented.
  • the catalyst is not limited to the catalyst used in the above embodiment.
  • a Ru-based catalyst may be used as the reforming catalyst.
  • the cooling conditions differ depending on the type of catalyst.
  • the reforming catalyst Ru catalyst is widely used especially for hydrogen generators for household fuel cells because of its ease of use, such as the difficulty of carbon deposition.
  • the cost is high.
  • the Ni catalyst used in the above embodiment can be obtained at a low cost.
  • the temperature at which purging (substitution) in the apparatus using the raw material is possible is Ru. Lower than the catalyst.
  • the upper limit of the purging temperature varies depending on the catalyst type, and is about 400 to 500 ° C. for the Ru catalyst and about 300 to 400 ° C. for the Ni catalyst.
  • the catalyst used in each reactor of the hydrogen generator has different operating temperatures and amounts depending on the configuration of the apparatus, and the temperature at which condensation starts is also different.
  • the cooling conditions of the reformer and the transformer are different depending on the catalyst type, and the temperature drop state is also different depending on the configuration of the apparatus. Therefore, by using an appropriate reference value of T1 to T3 for each apparatus, It is possible to suppress energy spent for preventing condensation at the time of stopping.
  • the fuel cell system and the fuel cell system stopping method according to the present invention can suppress dew condensation in the CO remover while improving energy saving than before in the period until the purge operation is performed. It is useful as a fuel cell system for home use or business use.

Abstract

Disclosed is a fuel cell system that controls condensation in a CO removal device during the period before a purge is performed, while further improving energy conservation over existing systems. The fuel cell system is equipped with a controller (13), and a hydrogen generation device (1) equipped with an oxidation gas supply unit (23) that supplies oxidation gas to the CO removal device (15). When halting power-generating operation, the controller performs at least either a first control that, before halting the power-generating operation, controls a manipulated variable of the oxidation gas supply unit in a manner such that the amount of oxidation gas supplied in relation to the amount of hydrogen-containing gas supplied to the CO removal device (15) is larger than during the power-generating operation (i), or a second control that, after halting the power-generating operation, controls the manipulated variable of the oxidation gas supply unit during a period in which hydrogen-containing gas is delivered by a reformer (14) in a manner such that the amount of oxidation gas supplied in relation to the amount of hydrogen-containing gas supplied to the CO removal device is larger than during the power-generating operation (ii); and after performing at least either the first control or the second control, the controller performs a purge within the hydrogen generation device.

Description

燃料電池システム、及び燃料電池システムの運転方法Fuel cell system and method for operating fuel cell system
　本発明は、化石原料等から水素含有ガスを生成する水素生成装置を備える燃料電池システム、及び燃料電池システムの運転方法に関する。 The present invention relates to a fuel cell system including a hydrogen generator that generates a hydrogen-containing gas from a fossil raw material and the like, and an operation method of the fuel cell system.
　小型装置でも高効率な発電を可能とする燃料電池は、分散型エネルギー供給源の発電システムとして開発が進められている。発電時の燃料となる水素ガスは、一般的なインフラとして整備されていないので、例えば都市ガス、プロパンガス等の既存の化石原料インフラから供給される原料を利用し、それらの原料と水との改質反応により水素含有ガスを生成させる水素生成装置が燃料電池に併設される。 Development of fuel cells that enable high-efficiency power generation even with small devices is being developed as a power generation system for distributed energy sources. Since hydrogen gas that serves as fuel for power generation is not developed as a general infrastructure, for example, raw materials supplied from existing fossil raw material infrastructure such as city gas and propane gas are used. A hydrogen generator for generating a hydrogen-containing gas by the reforming reaction is provided in the fuel cell.
　その水素生成装置は、原料と水とを改質反応させる改質器、水素ガス中の原料由来の一酸化炭素濃度を低減するために一酸化炭素と水蒸気を水性ガスシフト反応させる変成器、および一酸化炭素を主に微量空気等の酸化ガスで酸化させて一酸化炭素をより低減させるＣＯ除去器を設ける構成がとられることが多い。また、それらの反応器には、各反応に適した触媒、例えば、改質器にはＲｕ触媒やＮｉ触媒、変成器にはＣｕ－Ｚｎ触媒、ＣＯ除去器にはＲｕ触媒等が用いられている。各反応器には適した温度があり、改質器は６００～７００℃程度、変成器としては３５０～２００℃程度、ＣＯ除去器としては２００℃～１００℃程度で使用されることが多い。特に固体高分子型燃料電池はＣＯによる電極被毒が起こりやすいため、供給される水素含有ガス中のＣＯ濃度は数十体積ｐｐｍに抑える必要がある。そこで、ＣＯ除去器では水素含有ガス中に含まれるＣＯを酸化させることによってＣＯ濃度が低減される。 The hydrogen generator includes a reformer that reforms and reacts a raw material and water, a transformer that shifts a carbon monoxide and water vapor to a water gas in order to reduce the concentration of carbon monoxide derived from the raw material in hydrogen gas, and one In many cases, a structure is provided in which a CO remover that oxidizes carbon oxide mainly with an oxidizing gas such as a minute amount of air to further reduce carbon monoxide is provided. In these reactors, a catalyst suitable for each reaction, for example, a Ru catalyst or Ni catalyst is used for the reformer, a Cu-Zn catalyst is used for the shifter, a Ru catalyst is used for the CO remover, and the like. Yes. Each reactor has a suitable temperature. The reformer is often used at about 600 to 700 ° C., the reformer is used at about 350 to 200 ° C., and the CO remover is used at about 200 to 100 ° C. In particular, since solid polymer fuel cells are susceptible to electrode poisoning by CO, the CO concentration in the supplied hydrogen-containing gas must be suppressed to several tens of volume ppm. Therefore, in the CO remover, the CO concentration is reduced by oxidizing the CO contained in the hydrogen-containing gas.
　ところで、上記のような構成を有する水素生成装置において、改質触媒は高温で原料ガスにさらされると炭素析出が起こり、その結果として流路閉塞や活性低下が起こる。また、変成触媒や酸化触媒は結露による水濡れで、強度低下や活性低下が起こることが広く知られている。 By the way, in the hydrogen generator having the above-described configuration, when the reforming catalyst is exposed to the raw material gas at a high temperature, carbon deposition occurs, and as a result, the flow path is blocked and the activity is reduced. In addition, it is widely known that a shift catalyst and an oxidation catalyst cause a decrease in strength and a decrease in activity when wet due to condensation.
　ここで、改質器の温度が原料の熱分解により炭素析出しない温度で、かつＣＯ除去器で結露が生じない温度である状態において、水素生成装置内を原料でパージする方法が考案されている（例えば、特許文献１参照）。 Here, a method has been devised in which the hydrogen generator is purged with the raw material in a state where the temperature of the reformer is a temperature at which carbon does not precipitate due to thermal decomposition of the raw material and no condensation occurs in the CO remover. (For example, refer to Patent Document 1).
　また、停止処理中において酸化触媒への結露防止のために、ＣＯ除去器に設けられたヒーターにより加熱したり、運転停止後もＣＯ除去器への空気の供給を継続することでＣＯ除去器よりも下流のガス経路内の露点を低下させ、結露を抑制することが開示されている（例えば、特許文献２参照）。 In order to prevent dew condensation on the oxidation catalyst during the stop process, the CO remover can be heated by a heater provided in the CO remover or by continuing to supply air to the CO remover even after the operation is stopped. In addition, it is disclosed that the dew point in the downstream gas path is lowered to suppress dew condensation (see, for example, Patent Document 2).
特開２００４－３０７２３６号公報JP 2004-307236 A ＷＯ０２／０９０２４９号公報WO02 / 090249
　ここで、上記特許文献１の水素生成装置では、パージ動作による改質触媒の劣化を抑制するために、水素含有ガスの生成動作中において相対的に制御温度の高い改質器が、パージ動作可能な温度に低下するまでは、パージ動作は実施されない。 Here, in the hydrogen generator of Patent Document 1, in order to suppress the deterioration of the reforming catalyst due to the purge operation, the reformer having a relatively high control temperature can perform the purge operation during the generation operation of the hydrogen-containing gas. The purge operation is not performed until the temperature is reduced to a proper temperature.
　しかしながら、水素含有ガスの生成動作中において相対的に制御温度の低いＣＯ除去器では、改質器がパージ可能な温度にまで低下する間に、結露が生じてしまう可能性がある。 However, in the CO remover having a relatively low control temperature during the operation of generating the hydrogen-containing gas, condensation may occur while the reformer is lowered to a purgeable temperature.
　そこで、特許文献２に記載のようにＣＯ除去器に設けられたヒーターで結露しないよう加熱されるが、これにより省エネルギー性は低下してしまう。 Therefore, as described in Patent Document 2, the heater provided in the CO remover is heated so as not to condense, but this reduces energy saving.
　本発明は、上記課題を解決するものであり、上記パージ動作が実行されるまでの期間において、より従来よりも省エネ性を向上させながらＣＯ除去器での結露を抑制する燃料電池システム、及び燃料電池システムの運転方法を提供することを目的とする。 The present invention solves the above-described problem, and in the period until the purge operation is performed, a fuel cell system that suppresses dew condensation in a CO remover while improving energy saving performance more than the conventional one, and fuel It aims at providing the operating method of a battery system.
　上記目的を達成するために、本発明の燃料電池システムは、
　原料を用いて水素含有ガスを生成させる改質触媒を有する改質器、前記水素含有ガス中に含まれる一酸化炭素を酸化反応により低減させるための酸化触媒を有するＣＯ除去器、及び前記ＣＯ除去器に酸化ガスを供給する第１の酸化ガス供給器を備える水素生成装置と、前記水素生成装置から供給される水素含有ガスを用いて発電を行う燃料電池と、制御器とを備える燃料電池システムであって、
　前記制御器は、
　前記燃料電池システムの発電運転を停止させる際に、
(ｉ)前記停止に先行して、前記ＣＯ除去器への水素含有ガスの供給量に対する酸化ガスの供給量が、発電運転時よりも多くなるよう前記酸化ガス供給器の操作量を制御する第１の制御、及び
(ii)前記停止後、前記改質器より前記水素含有ガスが送出される期間において、前記ＣＯ除去器への水素含有ガスの供給量に対する酸化ガスの供給量が、発電運転時よりも多くなるよう前記酸化ガス供給器の操作量を制御する第２の制御、の少なくともいずれか一方を実行し、
　前記第１の制御及び第２の制御の少なくともいずれか一方を実行後に、前記水素生成装置内のパージ動作を実行することを特徴とする。 In order to achieve the above object, the fuel cell system of the present invention comprises:
A reformer having a reforming catalyst that generates a hydrogen-containing gas using a raw material, a CO remover having an oxidation catalyst for reducing carbon monoxide contained in the hydrogen-containing gas by an oxidation reaction, and the CO removal A fuel cell system comprising: a hydrogen generator comprising a first oxidant gas supplier for supplying an oxidant gas to the vessel; a fuel cell for generating electricity using the hydrogen-containing gas supplied from the hydrogen generator; and a controller Because
The controller is
When stopping the power generation operation of the fuel cell system,
(i) Prior to the stop, the operating amount of the oxidizing gas supplier is controlled so that the supply amount of the oxidizing gas with respect to the supply amount of the hydrogen-containing gas to the CO remover is larger than that during the power generation operation. 1 control, and
(ii) In the period in which the hydrogen-containing gas is sent from the reformer after the stop, the supply amount of the oxidizing gas with respect to the supply amount of the hydrogen-containing gas to the CO remover is larger than that during power generation operation. Performing at least one of the second control for controlling the operation amount of the oxidizing gas supplier,
A purge operation in the hydrogen generator is performed after at least one of the first control and the second control is performed.
　又、本発明の燃料電池システムの運転方法は、原料を用いて水素含有ガスを生成させる改質触媒を有する改質器、前記水素含有ガス中に含まれる一酸化炭素を酸化反応により低減させるための酸化触媒を有するＣＯ除去器、及び前記ＣＯ除去器に酸化ガスを供給する第１の酸化ガス供給器を備える水素生成装置と、前記水素生成装置から供給される水素含有ガスを用いて発電を行う燃料電池とを備える燃料電池システムの運転方法であって、
前記燃料電池システムの発電運転を停止させる際に、
(ｉ)前記停止に先行して、前記ＣＯ除去器への水素含有ガスの供給量に対する酸化ガスの供給量が、発電運転時よりも多くなるよう前記酸化ガス供給器の操作量を制御する第１の制御、及び
(ii)前記停止後、前記改質器より前記水素含有ガスが送出される期間において、前記ＣＯ除去器への水素含有ガスの供給量に対する酸化ガスの供給量が、発電運転時よりも多くなるよう前記酸化ガス供給器の操作量を制御する第２の制御、の少なくともいずれか一方を実行し、
　前記第１の制御及び第２の制御の少なくともいずれか一方を実行後に、前記水素生成装置内のパージ動作を実行することを特徴とする。 Further, the operating method of the fuel cell system of the present invention includes a reformer having a reforming catalyst for generating a hydrogen-containing gas using raw materials, and reducing carbon monoxide contained in the hydrogen-containing gas by an oxidation reaction. A hydrogen generator comprising a CO remover having an oxidation catalyst, a first oxidizing gas supplier for supplying an oxidizing gas to the CO remover, and a hydrogen-containing gas supplied from the hydrogen generator to generate power. An operation method of a fuel cell system comprising a fuel cell to perform,
When stopping the power generation operation of the fuel cell system,
(i) Prior to the stop, the operating amount of the oxidizing gas supplier is controlled so that the supply amount of the oxidizing gas with respect to the supply amount of the hydrogen-containing gas to the CO remover is larger than that during the power generation operation. 1 control, and
(ii) In the period in which the hydrogen-containing gas is sent from the reformer after the stop, the supply amount of the oxidizing gas with respect to the supply amount of the hydrogen-containing gas to the CO remover is larger than that during power generation operation. Performing at least one of the second control for controlling the operation amount of the oxidizing gas supply device,
A purge operation in the hydrogen generator is performed after at least one of the first control and the second control is performed.
　本発明によれば、パージ動作が実行されるまでの期間において、従来よりも省エネ性を向上させながらＣＯ除去器での結露を抑制する燃料電池システム、及び燃料電池システムの運転方法を提供することができる。 According to the present invention, there are provided a fuel cell system and a fuel cell system operation method that suppress dew condensation in a CO remover while improving energy saving performance over the period until a purge operation is performed. Can do.
実施の形態１における燃料電池システムの構成図Configuration diagram of fuel cell system according to Embodiment 1 実施の形態１における燃料電池システムの停止方法のフロー図Flow chart of stopping method of fuel cell system in Embodiment 1 実施の形態２における燃料電池システムの停止方法のフロー図Flow chart of stopping method of fuel cell system in Embodiment 2 実施の形態２の変形例１における燃料電池システムの停止方法のフロー図Flow chart of stopping method of fuel cell system in Modification 1 of Embodiment 2 実施の形態２の変形例１の更なる変形例における燃料電池システムの停止方法のフロー図Flow chart of a fuel cell system stopping method in a further modification of the first modification of the second embodiment 実施の形態２の変形例２における燃料電池システムの停止方法のフロー図Flow chart of a fuel cell system stopping method in the second modification of the second embodiment 実施の形態３における燃料電池システムの構成図Configuration diagram of fuel cell system according to Embodiment 3 実施の形態３における燃料電池システムの停止方法のフロー図Flow chart of stopping method of fuel cell system in Embodiment 3 実施例１における改質器、及びＣＯ除去器の温度の経時変化のグラフを示す図The figure which shows the graph of the time-dependent change of the temperature of the reformer in Example 1, and a CO remover. 比較例１における改質器１４、及びＣＯ除去器の温度の経時変化のグラフを示す図The figure which shows the graph of the time-dependent change of the temperature of the reformer 14 and the CO remover in the comparative example 1. 実施の形態１～３及び実施例１の変形例における燃料電池システムの停止方法のフロー図Flow chart of stopping method of fuel cell system in first to third embodiments and modified example of embodiment 1
　本発明の実施の形態に係る燃料電池システムは、原料を用いて水素含有ガスを生成させる改質触媒を有する改質器、水素含有ガス中に含まれる一酸化炭素を酸化反応により低減させるための酸化触媒を有するＣＯ除去器、及びＣＯ除去器に酸化ガスを供給する第１の酸化ガス供給器を備える水素生成装置と、水素生成装置から供給される水素含有ガスを用いて発電を行う燃料電池と、制御器とを備える燃料電池システムであって、制御器は、燃料電池システムの発電運転を停止させる際に、(ｉ)停止に先行して、ＣＯ除去器への水素含有ガスの供給量に対する酸化ガスの供給量が、発電運転時よりも多くなるよう酸化ガス供給器の操作量を制御する第１の制御、及び(ii)停止後、改質器より水素含有ガスが送出される期間において、ＣＯ除去器への水素含有ガスの供給量に対する酸化ガスの供給量が、発電運転時よりも多くなるよう酸化ガス供給器の操作量を制御する第２の制御、の少なくともいずれか一方を実行し、第１の制御及び第２の制御の少なくともいずれか一方を実行後に、水素生成装置内のパージ動作を実行することを特徴とする。 A fuel cell system according to an embodiment of the present invention includes a reformer having a reforming catalyst that generates a hydrogen-containing gas using raw materials, and a method for reducing carbon monoxide contained in the hydrogen-containing gas by an oxidation reaction. A hydrogen generator comprising a CO eliminator having an oxidation catalyst, a first oxidant gas supplier for supplying an oxidant gas to the CO eliminator, and a fuel cell for generating electricity using a hydrogen-containing gas supplied from the hydrogen generator And a controller, when the controller stops the power generation operation of the fuel cell system, (i) the supply amount of the hydrogen-containing gas to the CO remover prior to the stop And (ii) a period in which the hydrogen-containing gas is sent from the reformer after being stopped. CO removal And executing at least one of the second control for controlling the operation amount of the oxidizing gas supply device so that the supply amount of the oxidizing gas with respect to the supply amount of the hydrogen-containing gas to the power generation operation is larger than that during the power generation operation, A purge operation in the hydrogen generator is performed after performing at least one of the above control and the second control.
　また、本発明の実施の形態に係る燃料電池システムの運転方法は、原料を用いて水素含有ガスを生成させる改質触媒を有する改質器、水素含有ガス中に含まれる一酸化炭素を酸化反応により低減させるための酸化触媒を有するＣＯ除去器、及びＣＯ除去器に酸化ガスを供給する第１の酸化ガス供給器を備える水素生成装置と、水素生成装置から供給される水素含有ガスを用いて発電を行う燃料電池とを備える燃料電池システムの運転方法であって、燃料電池システムの発電運転を停止させる際に、(ｉ)停止に先行して、ＣＯ除去器への水素含有ガスの供給量に対する酸化ガスの供給量が、発電運転時よりも多くなるよう酸化ガス供給器の操作量を制御する第１の制御、及び(ii)停止後、改質器より水素含有ガスが送出される期間において、ＣＯ除去器への水素含有ガスの供給量に対する酸化ガスの供給量が、発電運転時よりも多くなるよう酸化ガス供給器の操作量を制御する第２の制御、の少なくともいずれか一方を実行し、第１の制御及び第２の制御の少なくともいずれか一方を実行後に、水素生成装置内のパージ動作を実行することを特徴とする。 The operation method of the fuel cell system according to the embodiment of the present invention includes a reformer having a reforming catalyst that generates a hydrogen-containing gas using raw materials, and an oxidation reaction of carbon monoxide contained in the hydrogen-containing gas. Using a hydrogen generator having a CO remover having an oxidation catalyst for reducing the gas, a first oxidizing gas supplier for supplying an oxidizing gas to the CO remover, and a hydrogen-containing gas supplied from the hydrogen generator An operation method of a fuel cell system including a fuel cell that generates power, and when stopping the power generation operation of the fuel cell system, (i) the amount of hydrogen-containing gas supplied to the CO remover prior to the stop And (ii) a period in which the hydrogen-containing gas is sent from the reformer after being stopped. In C Performing at least one of the second control for controlling the operation amount of the oxidizing gas supply unit so that the supply amount of the oxidizing gas with respect to the supply amount of the hydrogen-containing gas to the remover is larger than that during the power generation operation, A purge operation in the hydrogen generator is performed after performing at least one of the first control and the second control.
　かかる構成により、パージ動作が実行されるまでの期間において、従来よりも省エネ性を向上させながらＣＯ除去器での結露の発生を抑制することが出来る。 With such a configuration, it is possible to suppress the occurrence of dew condensation in the CO remover while improving the energy saving than before in the period until the purge operation is performed.
　ここで、第２の制御において、改質器より水素含有ガスが送出される期間の全部の間、酸化剤ガス供給器の操作量を増加させても良いし、改質器より水素含有ガスが送出される期間の一部の間だけ酸化剤ガス供給器の操作量を増加するように酸化ガス供給器を制御してもよい。 Here, in the second control, the operation amount of the oxidant gas supply device may be increased during the entire period in which the hydrogen-containing gas is sent from the reformer, or the hydrogen-containing gas is supplied from the reformer. The oxidant gas supply may be controlled to increase the amount of operation of the oxidant gas supply only during a portion of the delivery period.
　また、パージ動作とは、水素生成装置内部に残留するガスを、残留ガスとは組成の異なる組成のガス（水蒸気を除く）で置換する動作として定義され、この置換ガスとしては、窒素等の不活性ガス、空気、原料ガス等が例示される。 The purge operation is defined as an operation in which a gas remaining in the hydrogen generator is replaced with a gas having a composition different from that of the residual gas (excluding water vapor). Examples thereof include active gas, air, and raw material gas.
　また、「停止に先行して」とは、制御器が、発電運転時に動作している機器の少なくとも１つに、発電運転を停止させるために停止指令を出力するのに先行する、という意味である。 Further, “prior to stop” means that the controller precedes at least one of the devices operating during the power generation operation to output a stop command to stop the power generation operation. is there.
　また、「停止後」とは、制御器が、発電運転時に動作している機器の少なくとも１つに、発電運転を停止させるために停止指令を出力した後、という意味である。 Also, “after stop” means that the controller has output a stop command to stop the power generation operation to at least one of the devices operating during the power generation operation.
　以下、実施の形態に係る燃料電池システムについて、図面を参照しながら説明する。 Hereinafter, the fuel cell system according to the embodiment will be described with reference to the drawings.
　（実施の形態１）
　実施の形態１に係る燃料電池システムは、制御器が、燃料電池システムの発電運転を停止させる際に、停止に先行して、ＣＯ除去器への水素含有ガスの供給量に対する酸化ガスの供給量が、発電運転時よりも多くなるよう酸化ガス供給器の操作量を制御する第１の制御を実行し、第１の制御実行後に、水素生成装置内のパージ動作を実行する。 (Embodiment 1)
In the fuel cell system according to Embodiment 1, when the controller stops the power generation operation of the fuel cell system, the supply amount of the oxidizing gas with respect to the supply amount of the hydrogen-containing gas to the CO remover prior to the stoppage. However, the first control for controlling the operation amount of the oxidizing gas supply unit is performed so as to be larger than that during the power generation operation, and the purge operation in the hydrogen generator is performed after the first control is performed.
　また、実施の形態１に係る燃料電池システムの運転方法は、燃料電池システムの発電運転を停止させる際に、停止に先行して、ＣＯ除去器への水素含有ガスの供給量に対する酸化ガスの供給量が、発電運転時よりも多くなるよう酸化ガス供給器の操作量を制御する第１の制御を実行し、第１の制御を実行後に、水素生成装置内のパージ動作を実行する。 Further, in the operation method of the fuel cell system according to Embodiment 1, when the power generation operation of the fuel cell system is stopped, the supply of the oxidizing gas with respect to the supply amount of the hydrogen-containing gas to the CO remover prior to the stop The first control for controlling the operation amount of the oxidizing gas supplier is executed so that the amount becomes larger than that during the power generation operation, and the purge operation in the hydrogen generator is executed after the first control is executed.
　はじめに、実施の形態１の燃料電池システムの構成について説明する。 First, the configuration of the fuel cell system according to Embodiment 1 will be described.
　図１は、実施の形態１における燃料電池システムの構成図である。本実施の形態の燃料電池システムは、水素生成装置１と、燃料電池１００を有している。この水素生成装置１は、メタンを主成分とする都市ガス、天然ガス、ＬＰＧ等の炭化水素等の、少なくとも炭素及び水素から構成される有機化合物を含む原料と水蒸気の改質反応を主に進行させ、水素含有ガスを生成させる装置である。また、燃料電池１００は、水素生成装置１から供給される水素含有ガスをアノードガスとして用い、別途カソードガス供給器１１０から供給される空気などの酸化剤ガスをカソードガスとして用い、両者を反応させて発電する装置である。 FIG. 1 is a configuration diagram of the fuel cell system according to the first embodiment. The fuel cell system according to the present embodiment includes a hydrogen generator 1 and a fuel cell 100. This hydrogen generation apparatus 1 mainly proceeds with a reforming reaction of a raw material containing an organic compound composed of at least carbon and hydrogen, such as city gas mainly composed of methane, natural gas, hydrocarbons such as LPG, and steam. To generate a hydrogen-containing gas. Further, the fuel cell 100 uses the hydrogen-containing gas supplied from the hydrogen generator 1 as an anode gas, and uses an oxidant gas such as air supplied from a cathode gas supplier 110 as a cathode gas, and causes both to react. It is a device that generates electricity.
　ここで、改質反応は、原料と水蒸気を用いる改質反応であれば、いずれのタイプの改質反応であってもよく、例えば、水蒸気改質反応やオートサーマル反応等が採用される。 Here, the reforming reaction may be any type of reforming reaction as long as it is a reforming reaction using a raw material and steam. For example, a steam reforming reaction or an autothermal reaction is adopted.
　ここで、燃料電池は、いずれのタイプの燃料電池であってもよく、固体高分子形燃料電池、りん酸形燃料電池、または固体酸化物形燃料電池などが採用される。 Here, the fuel cell may be any type of fuel cell, such as a polymer electrolyte fuel cell, a phosphoric acid fuel cell, or a solid oxide fuel cell.
　次に、図１中、点線で覆われている水素生成装置１の構成について説明する。 Next, the configuration of the hydrogen generator 1 covered with a dotted line in FIG. 1 will be described.
　本実施の形態の水素生成装置１には、原料と水蒸気から水素含有ガスを生成する水素生成器８が設けられている。この水素生成器８には、原料と水蒸気とを用いて改質反応を進行させる改質器１４と、その改質器１４で生成された水素含有ガス中の一酸化炭素を、選択酸化させることによって低減させるＣＯ除去器１５が設けられている。又、改質器１４から排出された水素含有ガスに、ＣＯ除去器１５における酸化に用いる空気を供給する酸化ガス供給器２３が設けられている。この改質器１４にはＮｉ系の改質触媒が設けられており、ＣＯ除去器１５には、Ｒｕ系の選択酸化触媒が設けられている。 The hydrogen generator 1 of the present embodiment is provided with a hydrogen generator 8 that generates a hydrogen-containing gas from a raw material and water vapor. The hydrogen generator 8 is configured to selectively oxidize carbon monoxide in the hydrogen-containing gas generated by the reformer 14 that progresses the reforming reaction using the raw material and steam and the reformer 14. A CO eliminator 15 is provided to reduce the amount. In addition, an oxidizing gas supply unit 23 is provided for supplying air used for oxidation in the CO remover 15 to the hydrogen-containing gas discharged from the reformer 14. The reformer 14 is provided with a Ni-based reforming catalyst, and the CO remover 15 is provided with a Ru-based selective oxidation catalyst.
　また、改質器１４における改質反応を進行させるための熱を発生する燃焼器２が設けられている。又、燃焼器２の着火源となるイグナイター２１と、燃焼器２の燃焼状態を検知するフレームロッド２２と、燃焼器２に燃焼用空気を供給する空気供給器２０が設けられている。この燃焼器２の加熱源となる燃焼ガスとしては、水素生成器８を通過した原料や、燃料電池１００のアノードから排出されたアノードオフガス等が用いられる。 Further, a combustor 2 that generates heat for causing the reforming reaction in the reformer 14 to proceed is provided. Further, an igniter 21 that is an ignition source of the combustor 2, a frame rod 22 that detects a combustion state of the combustor 2, and an air supply device 20 that supplies combustion air to the combustor 2 are provided. As the combustion gas that serves as a heating source for the combustor 2, a raw material that has passed through the hydrogen generator 8, an anode off-gas discharged from the anode of the fuel cell 100, and the like are used.
　また、改質器１４に水を供給するポンプである水供給器３と、改質器１４に原料を供給する原料供給器４が設けられている。なお、原料供給器４は、ブースターポンプとし、例えば入力する電流パルス、入力電力等を制御して流量調節できる構成とする。また、水供給器３は、原料供給器４と同様に流量調節機能を有するポンプとする。 Further, a water supply device 3 that is a pump for supplying water to the reformer 14 and a raw material supply device 4 for supplying raw materials to the reformer 14 are provided. The raw material supplier 4 is a booster pump, and is configured to control the flow rate by controlling, for example, input current pulses and input power. In addition, the water supply device 3 is a pump having a flow rate adjusting function similarly to the raw material supply device 4.
　また、原料の供給源としてガスインフラライン６が用いられている。そのガスインフラライン６に、吸着脱硫剤が充填されている吸着脱硫器５が接続され、吸着脱硫器５は原料供給器４に接続されている。また、水素生成器８で生成する水素含有ガスを燃料電池１００に供給するための水素ガス供給経路９が設けられている。更に、燃料電池１００で消費されなかった水素含有ガスを燃焼器２に供給するアノードオフガス供給経路１０が設けられている。また、燃料電池１００をバイパスして、水素ガス供給経路９とアノードオフガス供給経路１０とを接続するバイパス経路１２が設けられている。また、バイパス経路１２には開閉弁１１ａが設けられており、水素ガス供給経路９のバイパス経路１２への分岐箇所（図１中Ｐ参照）より下流側には開閉弁１１ｂが設けられている。尚、アノードオフガス供給経路１０へのバイパス経路１２の合流箇所は、図１中Ｑで示されている。 Also, the gas infrastructure 6 is used as a raw material supply source. An adsorbing desulfurizer 5 filled with an adsorbing desulfurizing agent is connected to the gas infrastructure line 6, and the adsorbing desulfurizer 5 is connected to the raw material supplier 4. Further, a hydrogen gas supply path 9 for supplying the hydrogen-containing gas generated by the hydrogen generator 8 to the fuel cell 100 is provided. Furthermore, an anode off-gas supply path 10 is provided for supplying the hydrogen-containing gas that has not been consumed by the fuel cell 100 to the combustor 2. Further, a bypass path 12 that bypasses the fuel cell 100 and connects the hydrogen gas supply path 9 and the anode off-gas supply path 10 is provided. The bypass path 12 is provided with an open / close valve 11a, and an open / close valve 11b is provided downstream of the branch point of the hydrogen gas supply path 9 to the bypass path 12 (see P in FIG. 1). The junction of the bypass path 12 to the anode off gas supply path 10 is indicated by Q in FIG.
　また、改質器１４及びＣＯ除去器１５にはそれぞれの触媒温度を検出するために、改質温度検出器２４、選択酸化温度検出器２５が設けられている。各検出器としては熱電対やサーミスタ等が用いられている。 Further, the reformer 14 and the CO remover 15 are provided with a reforming temperature detector 24 and a selective oxidation temperature detector 25 in order to detect respective catalyst temperatures. As each detector, a thermocouple, a thermistor, or the like is used.
　また、フレームロッド２２、改質温度検出器２４、及び選択酸化温度検出器２５からの検出値が入力され、原料供給器４から供給する原料の供給量や水供給器３から供給する水の供給量、空気供給器２０、開閉弁１１ａ、１１ｂ、及びイグナイター２１等を制御する制御器１３が設けられている（図１参照）。なお、制御器１３は、演算処理部と、上記第１の制御及び第２の制御の少なくともいずれか一つを実行するための制御プログラムが格納された記憶部とを備える。演算処理部は、例えば、マイクロプロセッサ、ＣＰＵ等から構成され、記憶部は、半導体メモリー等から構成される。また、制御器１３は、単独の制御器から構成される形態、または分散配置された複数の制御器から構成され、それらが協働して燃料電池システムを制御する形態のいずれも含む。 In addition, detection values from the frame rod 22, the reforming temperature detector 24, and the selective oxidation temperature detector 25 are input, and the supply amount of the raw material supplied from the raw material supply device 4 and the supply of water supplied from the water supply device 3. A controller 13 for controlling the amount, the air supply device 20, the on-off valves 11a and 11b, the igniter 21 and the like is provided (see FIG. 1). The controller 13 includes an arithmetic processing unit and a storage unit that stores a control program for executing at least one of the first control and the second control. The arithmetic processing unit is configured by, for example, a microprocessor, a CPU, and the like, and the storage unit is configured by a semiconductor memory or the like. Further, the controller 13 includes either a single controller or a plurality of distributed controllers that cooperate to control the fuel cell system.
　次に、本実施の形態１における燃料電池システムの動作について説明する。 Next, the operation of the fuel cell system in Embodiment 1 will be described.
　はじめに、本実施の形態１おける燃料電池システムの起動及び発電運転について説明する。 First, the start-up and power generation operation of the fuel cell system in the first embodiment will be described.
　停止状態から水素生成装置１を起動させる場合、制御器１３からの指令により、原料が原料供給器４から水素生成器８へと供給される。この際、開閉弁１１ａが開状態、開閉弁１１ｂが閉状態になっており、水素生成器８から排出された原料はバイパス経路１２を経由して燃焼器２へと供給される。その原料を燃料として、燃焼器２において着火されて加熱が開始される。そして、結露が発生しない温度まで、改質器１４、及びＣＯ除去器１５が昇温された段階で、制御器１３は水供給器３を動作し、水が改質器１４に供給され、水と原料との改質反応が開始される。 When starting the hydrogen generator 1 from the stopped state, the raw material is supplied from the raw material supplier 4 to the hydrogen generator 8 according to a command from the controller 13. At this time, the on-off valve 11 a is in the open state and the on-off valve 11 b is in the closed state, and the raw material discharged from the hydrogen generator 8 is supplied to the combustor 2 via the bypass path 12. The raw material is used as fuel and ignited in the combustor 2 to start heating. Then, when the reformer 14 and the CO remover 15 are heated to a temperature at which dew condensation does not occur, the controller 13 operates the water supply device 3 so that water is supplied to the reformer 14 and the water And the reforming reaction of the raw material is started.
　本実施の形態１では、メタンを主成分とする都市ガス（１３Ａ）が原料として用いられる。水の供給量は、供給都市ガスの平均分子式中の炭素原子数１モルに対して３モル程度の水蒸気を存在させる量が供給される（スチームカーボン比（Ｓ／Ｃ）で３程度）。ＣＯ除去器１５へは空気がＣＯ／Ｏ２モル比２～３程度になるよう酸化ガス供給器２３から供給される。 In this Embodiment 1, the city gas (13A) which has methane as a main component is used as a raw material. The amount of water supplied is such that about 3 mol of water vapor is present per 1 mol of carbon atoms in the average molecular formula of the supplied city gas (steam carbon ratio (S / C) is about 3). Air is supplied to the CO remover 15 from the oxidizing gas supply unit 23 so that the CO / O 2 molar ratio is about 2 to 3.
　改質器１４、及びＣＯ除去器１５が温まり、水蒸気改質反応、及び選択酸化反応が進行する。そして、水素含有ガス中の一酸化炭素の濃度が低減できた時点で、開閉弁１１ａを閉じ、開閉弁１１ｂを開放することにより、水素生成器８から排出されるガスの流路が燃料電池１００側に切り換えられ、水素含有ガスが、水素ガス供給経路９から燃料電池１００へと供給される。 The reformer 14 and the CO remover 15 are warmed, and the steam reforming reaction and the selective oxidation reaction proceed. When the concentration of carbon monoxide in the hydrogen-containing gas can be reduced, the on-off valve 11a is closed and the on-off valve 11b is opened so that the flow path of the gas discharged from the hydrogen generator 8 becomes the fuel cell 100. The hydrogen-containing gas is supplied from the hydrogen gas supply path 9 to the fuel cell 100.
　そして、燃料電池１００において、カソードガス供給器１１０から供給された空気と、水素含有ガスを用いて発電が行われる。尚、水蒸気改質反応は、吸熱反応であり、選択酸化反応は発熱反応である。又、発電時の改質器１４の温度は約４００～６５０℃、ＣＯ除去器１５の温度は１２０～１６０℃となっており、改質温度検出部２４で検出される温度は約６５０℃、選択酸化温度検出部２５で検出される温度は約１６０℃である。 In the fuel cell 100, power generation is performed using the air supplied from the cathode gas supply unit 110 and the hydrogen-containing gas. The steam reforming reaction is an endothermic reaction, and the selective oxidation reaction is an exothermic reaction. The temperature of the reformer 14 during power generation is about 400 to 650 ° C., the temperature of the CO remover 15 is 120 to 160 ° C., and the temperature detected by the reforming temperature detector 24 is about 650 ° C. The temperature detected by the selective oxidation temperature detector 25 is about 160 ° C.
　次に、本実施の形態１の燃料電池システムの運転の停止方法の一例について説明する。 Next, an example of a method for stopping the operation of the fuel cell system according to the first embodiment will be described.
　燃料電池システムの運転を停止させる停止指令を制御器１３が出力することによって、カソードガス供給器１１０が停止されるとともに、水素生成装置１の運転も停止される。 When the controller 13 outputs a stop command for stopping the operation of the fuel cell system, the cathode gas supply device 110 is stopped and the operation of the hydrogen generator 1 is also stopped.
　次に、水素生成装置１の運転を停止させる方法の概略について説明すると、原料と水の供給を停止させることによって、燃焼器２の燃焼も停止し、水素生成器８内の改質器１４及びＣＯ除去器１５の各触媒層の温度が低下する。各触媒層の温度が設定温度まで低下した後、水素生成装置１に原料を供給することによって、水素生成装置１のガス経路内部に滞留する水素含有ガスが原料で置換される。 Next, an outline of a method for stopping the operation of the hydrogen generator 1 will be described. By stopping the supply of raw materials and water, the combustion of the combustor 2 is also stopped, and the reformer 14 in the hydrogen generator 8 and The temperature of each catalyst layer of the CO remover 15 decreases. After the temperature of each catalyst layer is lowered to the set temperature, the raw material is supplied to the hydrogen generator 1, whereby the hydrogen-containing gas staying inside the gas path of the hydrogen generator 1 is replaced with the raw material.
　このとき、原料ガスによって追い出された水素含有ガスは、燃焼器２へと供給される。燃焼器２で水素含有ガスが燃焼されると、燃焼器２の加熱により改質器１４の温度が上昇し炭素析出の恐れが生じる。そのため、燃焼器２による改質器１４の温度上昇分を見込んで、できるだけ低い温度でパージを実施することが望ましい。なお、上記パージ動作において水素生成装置内から掃気される水素含有ガスを空気等によって燃焼させずに希釈排気する方法もあるが、エネルギーの有効活用という観点からは燃焼させることが望ましい。 At this time, the hydrogen-containing gas expelled by the raw material gas is supplied to the combustor 2. When the hydrogen-containing gas is combusted in the combustor 2, the temperature of the reformer 14 rises due to heating of the combustor 2, which may cause carbon deposition. Therefore, it is desirable to perform the purge at the lowest possible temperature in anticipation of the temperature rise of the reformer 14 by the combustor 2. Although there is a method of diluting and exhausting the hydrogen-containing gas scavenged from the hydrogen generator in the purge operation without burning it with air or the like, it is desirable to burn it from the viewpoint of effective use of energy.
　このような燃料電池システムの発電停止前に、制御器１３が、以下の動作を行うことが、本実施の形態における特徴的な動作となる。 The characteristic operation in the present embodiment is that the controller 13 performs the following operation before stopping the power generation of such a fuel cell system.
　図２は、本実施の形態１の燃料電池システムの停止方法の制御フローを示す図である。尚、この図２では、ステップをＳと省略して示している。以下の図においても同様である。また、図２における制御が行われるトリガーとしては、電力需要の低下に伴い発電運転を停止すると制御器が判断した場合や、ユーザーが操作器（例えば、リモコン）を介して燃料電池システムの発電停止を要求する場合等が挙げられる。 FIG. 2 is a diagram showing a control flow of the stopping method of the fuel cell system according to the first embodiment. In FIG. 2, step is abbreviated as S. The same applies to the following drawings. In addition, as a trigger for performing the control in FIG. 2, when the controller determines that the power generation operation is stopped due to a decrease in power demand, or when the user stops the power generation of the fuel cell system via an operating device (for example, a remote controller). Is required.
　はじめに、ステップ１において、制御器１３は、停止指令を出す時刻Ｈ１を決定する。 First, in step 1, the controller 13 determines a time H1 at which a stop command is issued.
　次に、ステップ２において、停止指令を行うタイミングまでの残り運転時間（時刻Ｈ１―現在の時刻ｔ）が予め設定される時間Ｈ０を下回っているかどうかの判定が行われ、発電停止までの残り時間が予め設定される時間Ｈ０を下回ると、制御はステップ３へ移行する。具体的には、例えば、Ｈ１を現在時刻から２０分後の２３時２０分とし、Ｈ０を１０分間とすると、時刻ｔが、２３時１０分を超えると、Ｈ１―ｔがＨ０よりも小さくなるため、制御がステップ３へと進むことになる。 Next, in step 2, it is determined whether or not the remaining operating time (time H1−current time t) until the timing of issuing the stop command is less than a preset time H0, and the remaining time until the power generation stops. Falls below the preset time H0, the control shifts to step 3. Specifically, for example, when H1 is 23:20, 20 minutes after the current time, and H0 is 10 minutes, when time t exceeds 23:10, H1-t becomes smaller than H0. Therefore, the control proceeds to step 3.
　そして、ステップ３では、選択酸化触媒の温度が発電運転時における制御温度よりも高くなるよう酸化ガス供給器２３の操作量を制御する指示が制御器１３から出される。具体的には、選択酸化触媒の温度が発電運転時における制御温度よりも高くなるよう酸化ガス供給器２３の操作量を、直前の操作量よりも増加する制御が行われる。 In step 3, the controller 13 issues an instruction to control the operation amount of the oxidizing gas supply device 23 so that the temperature of the selective oxidation catalyst becomes higher than the control temperature during the power generation operation. Specifically, control is performed such that the operating amount of the oxidizing gas supply device 23 is increased from the immediately preceding operating amount so that the temperature of the selective oxidation catalyst becomes higher than the control temperature during power generation operation.
　上記制御は、換言すれば、ＣＯ除去器１５への水素含有ガスの供給量に対する酸化ガス（空気）の供給量が、発電運転時よりも多くなるよう酸化ガス供給器２３の操作量が制御される。
また、この制御により、ＣＯ除去器１５を流れる水素含有ガス中の水素と空気中の酸素との酸化反応量が増加し、酸化反応に伴う発熱により、選択酸化触媒の温度が発電運転時における制御温度よりも高くなる。 In other words, the operation amount of the oxidizing gas supplier 23 is controlled so that the supply amount of the oxidizing gas (air) with respect to the supply amount of the hydrogen-containing gas to the CO remover 15 is larger than that during the power generation operation. The
Further, by this control, the amount of oxidation reaction between hydrogen in the hydrogen-containing gas flowing through the CO remover 15 and oxygen in the air increases, and the temperature of the selective oxidation catalyst is controlled during power generation operation due to heat generated by the oxidation reaction. It becomes higher than the temperature.
　次いでステップ４へ移行し、システムの停止指令を出すタイミングか否かの判定がなされる。すなわち、現在時刻ｔがＨ１を超えたか否かが判定される。停止指令タイミングを超えていない場合（ｔ≦Ｈ１の場合）は、停止指令タイミングＨ１を超えるまでの間、酸化ガス供給器２３からの空気供給量が増量された状態が保持される。 Next, the routine proceeds to step 4 where it is determined whether or not it is time to issue a system stop command. That is, it is determined whether or not the current time t has exceeded H1. When the stop command timing is not exceeded (when t ≦ H1), the state in which the amount of air supplied from the oxidizing gas supplier 23 is increased until the stop command timing H1 is exceeded.
　そして、現在時刻ｔが停止指令タイミングを超える（ｔ＞Ｈ１）と、制御はステップ５へと移行し、制御器１３が停止指令を出す。停止指令が出されると、ステップ６において制御器１３が開閉弁１１ａを開状態、開閉弁１１ｂを閉状態とする。このように開閉弁１１ａ、１１ｂを切り替えることにより、水素生成器８から排出されたガスが燃料電池１００へと供給されず、バイパス経路１２を介して、燃焼器２へと送られる。 When the current time t exceeds the stop command timing (t> H1), the control shifts to step 5 and the controller 13 issues a stop command. When the stop command is issued, in step 6, the controller 13 opens the on-off valve 11a and closes the on-off valve 11b. By switching the on-off valves 11 a and 11 b in this way, the gas discharged from the hydrogen generator 8 is not supplied to the fuel cell 100 but is sent to the combustor 2 via the bypass path 12.
　次に、ステップ７において、カソードガス供給器１１０の動作も停止され、燃料電池１００における発電が停止される。又、制御器１３は、水供給器３、原料供給器４及び酸化ガス供給器２３を停止するように制御を行い、水蒸気改質反応が停止される。 Next, in Step 7, the operation of the cathode gas supply device 110 is also stopped, and the power generation in the fuel cell 100 is stopped. Further, the controller 13 performs control to stop the water supplier 3, the raw material supplier 4, and the oxidizing gas supplier 23, and the steam reforming reaction is stopped.
　このように、ステップ６、７において、燃料電池１００の発電及び水素生成装置１の運転が停止されると、改質器１４及びＣＯ除去器１５の各触媒層の温度が除々に低下する。 Thus, when the power generation of the fuel cell 100 and the operation of the hydrogen generator 1 are stopped in Steps 6 and 7, the temperatures of the catalyst layers of the reformer 14 and the CO remover 15 gradually decrease.
　続いて、ステップ８において、改質検出温度ＴＫが原料供給開始温度Ｔ１に達すると制御はステップ９へと進み、原料供給器４が動作して原料パージが行われる。尚、原料パージを行う前に、開閉弁１１ａを閉じ、開閉弁１１ｂを開く制御を行うことによって、水素生成器８から排出されたガスが燃料電池１００側に供給されるため、燃料電池１００の内部も原料ガスによってパージする形態を採用しても構わない。又、上述したように、燃焼器２における原料ガスの燃焼による改質器１４の温度上昇を考慮し、原料供給開始温度Ｔ１は、低く設定されている。具体的には、改質触媒としてＮｉ系の触媒を用いた場合には、改質触媒の温度が約３００℃まで下がると炭素析出がおこらないが、燃焼器２による温度上昇を見込んで、Ｔ１は約１５０℃に設定されている。 Subsequently, in step 8, when the reforming detection temperature TK reaches the raw material supply start temperature T1, the control proceeds to step 9, and the raw material supplier 4 operates to perform the raw material purge. Before performing the raw material purge, the gas discharged from the hydrogen generator 8 is supplied to the fuel cell 100 side by performing control to close the on-off valve 11a and open the on-off valve 11b. The inside may be purged with the source gas. Further, as described above, in consideration of the temperature rise of the reformer 14 due to the combustion of the raw material gas in the combustor 2, the raw material supply start temperature T1 is set low. Specifically, when a Ni-based catalyst is used as the reforming catalyst, carbon deposition does not occur when the temperature of the reforming catalyst falls to about 300 ° C., but T1 is expected in view of the temperature rise by the combustor 2. Is set to about 150 ° C.
　そして、水素生成器８内に滞留しているガスを置換できる十分な量の原料ガスを供給した後、ステップ１０において原料供給器４が停止される。 Then, after supplying a sufficient amount of raw material gas capable of replacing the gas staying in the hydrogen generator 8, the raw material supplier 4 is stopped in step 10.
　以上のように、本実施の形態では、第１の制御の一例として、酸化触媒の温度を発電運転時における制御温度よりも高くなるよう、停止指令前において、酸化ガス供給器２３の操作量の制御が行われる。そのため、従来の燃料電池システムよりも省エネ性を向上させながら、改質検出温度ＴＫがＴ１に達するまでの間の結露の発生を抑制することが出来る。 As described above, in the present embodiment, as an example of the first control, the operation amount of the oxidizing gas supply 23 is set before the stop command so that the temperature of the oxidation catalyst becomes higher than the control temperature during the power generation operation. Control is performed. Therefore, it is possible to suppress the occurrence of condensation until the reforming detection temperature TK reaches T1 while improving the energy saving performance as compared with the conventional fuel cell system.
　尚、本実施の形態における酸化ガス（空気）の供給量を増量した状態を保つ時間（Ｈ０）及び酸化ガス（空気）の増加量は、改質検出温度ＴＫがＴ１に達するまでの間に、ＣＯ除去器１５内の温度が結露温度に達しない程度の温度にＣＯ除去器１５がなるように設定されている。 The time (H0) for maintaining the state in which the supply amount of the oxidizing gas (air) in the present embodiment is increased and the increase amount of the oxidizing gas (air) are determined until the reforming detection temperature TK reaches T1. The CO remover 15 is set so that the temperature in the CO remover 15 does not reach the dew condensation temperature.
　又、本実施の形態では、図２に示す制御フローを実行するトリガーの後、停止指令を発する時刻Ｈ１を決定し、現在時刻ｔとの差を求めて、その差がＨ０よりも小さくなると酸化ガス供給器２３による空気の供給量を増量させているが、停止指令を発する時刻Ｈ１を決定せずに、制御フローを実行するトリガーの後、すぐに時間Ｈ０の間、酸化ガス供給器２３による空気の供給量を増加する制御が行われても良い。つまり、燃料電池システムの発電停止に先行して、酸化ガス供給器２３の操作量を増加する制御が実行されるなら、如何なる形態であっても構わない。 Further, in the present embodiment, after the trigger for executing the control flow shown in FIG. 2, the time H1 at which the stop command is issued is determined, the difference from the current time t is obtained, and if the difference becomes smaller than H0, the oxidation is performed. Although the amount of air supplied from the gas supplier 23 is increased, the oxidizing gas supplier 23 immediately follows the trigger for executing the control flow without determining the time H1 at which the stop command is issued. Control for increasing the supply amount of air may be performed. That is, any form may be used as long as the control for increasing the operation amount of the oxidizing gas supply unit 23 is executed prior to the stop of power generation in the fuel cell system.
　（実施の形態２）
　実施の形態２に係る燃料電池システムは、制御器が、燃料電池システムの発電運転を停止させる際に、停止後、改質器より水素含有ガスが送出される期間において、ＣＯ除去器への水素含有ガスの供給量に対する酸化ガスの供給量が、発電運転時よりも多くなるよう酸化ガス供給器の操作量を制御する第２の制御を実行し、第２の制御を実行後に、水素生成装置内のパージ動作を実行する。 (Embodiment 2)
In the fuel cell system according to Embodiment 2, when the controller stops the power generation operation of the fuel cell system, hydrogen is supplied to the CO remover during the period in which the hydrogen-containing gas is sent from the reformer after the stop. The second generation control for controlling the operation amount of the oxidizing gas supply unit is executed so that the supply amount of the oxidizing gas with respect to the supply amount of the contained gas is larger than that during the power generation operation. The purge operation is executed.
　また、実施の形態２に係る燃料電池システムの運転方法は、燃料電池システムの発電運転を停止させる際に、停止後、改質器より水素含有ガスが送出される期間において、ＣＯ除去器への水素含有ガスの供給量に対する酸化ガスの供給量が、発電運転時よりも多くなるよう酸化ガス供給器の操作量を制御する第２の制御を実行し、第２の制御を実行後に、水素生成装置内のパージ動作を実行する。 Further, in the operation method of the fuel cell system according to the second embodiment, when stopping the power generation operation of the fuel cell system, after the stop, the hydrogen-containing gas is sent from the reformer to the CO remover. The second control for controlling the operation amount of the oxidizing gas supply unit is executed so that the supply amount of the oxidizing gas with respect to the supply amount of the hydrogen-containing gas is larger than that during the power generation operation, and hydrogen is generated after the second control is executed. A purge operation in the apparatus is executed.
　ここで、停止後、改質器より水素含有ガスが送出される期間は、反応ガス供給器を停止した後に、改質器内に残留した反応ガスから生成された水素含有ガスがＣＯ除去器に送出される期間を含む。 Here, after the shutdown, the hydrogen-containing gas is sent from the reformer. After the reaction gas supply device is stopped, the hydrogen-containing gas generated from the reaction gas remaining in the reformer is supplied to the CO remover. Includes the time period to be sent.
　ここで、反応ガス供給器は、改質器に改質反応に用いられる反応ガスを供給する機器であり、具体的には、改質器に原料を供給する原料供給器、改質器に水を供給する水供給器等が挙げられる。なお、改質反応が、オートサーマル法である場合は、反応ガス供給器には、酸化ガス供給器も含まれ得る。 Here, the reaction gas supply device is a device that supplies a reaction gas used for the reforming reaction to the reformer. Specifically, the reaction gas supply device supplies a raw material to the reformer and supplies water to the reformer. A water supply device for supplying water. When the reforming reaction is an autothermal method, the reactive gas supply device may include an oxidizing gas supply device.
　また実施の形態２に係る燃料電池システムは、改質器を加熱するための燃焼器と、燃焼器における燃焼を検知する燃焼検知器と、ＣＯ除去器より送出されたガスが燃焼器に流入するためのガス流路と、ガス流路を連通／遮断させる開閉弁と、を備え、停止後、改質器より水素含有ガスが送出される期間は、停止後に開閉弁が開放している状態で、燃焼検知器で燃焼器の燃焼が検知されている期間を含んでもよい。 The fuel cell system according to Embodiment 2 includes a combustor for heating the reformer, a combustion detector for detecting combustion in the combustor, and a gas sent from the CO remover flows into the combustor. A gas flow path for opening and shutting off and opening / closing the gas flow path, and after the stop, the hydrogen-containing gas is sent from the reformer in a state where the open / close valve is open after the stop. A period during which combustion of the combustor is detected by the combustion detector may be included.
　これにより、改質器より水素含有ガスが送出されている期間においては、燃焼検知器により燃焼が検知されるため、適切なタイミングで酸化剤ガス供給器の操作量の増加制御を実行することが出来る。 As a result, during the period in which the hydrogen-containing gas is being sent out from the reformer, combustion is detected by the combustion detector, so that it is possible to execute an increase control of the operation amount of the oxidant gas supply device at an appropriate timing. I can do it.
　以下、実施の形態２における燃料電池システムについて説明する。 Hereinafter, the fuel cell system according to Embodiment 2 will be described.
　本実施の形態２の燃料電池システムは、基本的な構成は実施の形態１と同様であるが、制御フローが異なっている。そのため、本相違点を中心に説明する。尚、実施の形態１と同様の構成については同一の符号を付している。 The basic configuration of the fuel cell system of the second embodiment is the same as that of the first embodiment, but the control flow is different. Therefore, this difference will be mainly described. In addition, the same code | symbol is attached | subjected about the structure similar to Embodiment 1. FIG.
　本実施の形態２の燃料電池システムの構成については、実施の形態１と同様であるため、説明は省略する。 Since the configuration of the fuel cell system of the second embodiment is the same as that of the first embodiment, description thereof is omitted.
　図３は、本実施の形態２の燃料電池システムの停止時の制御フローを示す図である。 FIG. 3 is a diagram showing a control flow when the fuel cell system according to Embodiment 2 is stopped.
　図３に示すように、本実施の形態２では、電力需要の低下に伴い発電運転を停止すると制御器が判断した場合や、ユーザーが操作器（例えば、リモコン）を介して燃料電池システムの発電停止を要求した場合に、はじめに制御器１３が、燃料電池システムを構成する各機器に停止指令を出す（ステップ２０参照）。この停止指令によって、燃料電池１００の発電運転及び水素生成装置１の運転の停止制御が開始される。 As shown in FIG. 3, in the second embodiment, when the controller determines that the power generation operation is stopped due to a decrease in power demand, or when the user generates power from the fuel cell system via an operating device (for example, a remote controller). When the stop is requested, the controller 13 first issues a stop command to each device constituting the fuel cell system (see step 20). With this stop command, stop control of the power generation operation of the fuel cell 100 and the operation of the hydrogen generator 1 is started.
　次のステップ２１にて、制御器１３は、開閉弁１１ａを開き、開閉弁１１ｂを閉じる。そして、ステップ２２にて、水供給器３、カソードガス供給器１１０、原料供給器４の動作が停止される。 In the next step 21, the controller 13 opens the on-off valve 11a and closes the on-off valve 11b. In step 22, the operations of the water supply device 3, the cathode gas supply device 110, and the raw material supply device 4 are stopped.
　次に、ステップ２３において、選択酸化触媒の温度が発電運転時における制御温度よりも高くなるよう酸化ガス供給器２３の操作量を制御する指示が制御器１３から出される。そして、酸化ガス供給器２３の操作量が、停止指令直前の操作量よりも増加するように制御が行われる。本制御では、換言すれば、ＣＯ除去器１５への水素含有ガスの供給量に対する酸化ガスの供給量が、発電運転時よりも多くなるよう酸化ガス供給器２３の操作量が制御される。 Next, in step 23, an instruction is issued from the controller 13 to control the operation amount of the oxidizing gas supply device 23 so that the temperature of the selective oxidation catalyst becomes higher than the control temperature during the power generation operation. And control is performed so that the operation amount of the oxidizing gas supply device 23 increases from the operation amount immediately before the stop command. In other words, in this control, the operation amount of the oxidizing gas supply unit 23 is controlled so that the supply amount of the oxidizing gas with respect to the supply amount of the hydrogen-containing gas to the CO remover 15 is larger than that during the power generation operation.
　そして、ステップ２４で燃焼器２の消火が検知されるまで、酸化ガス供給器２３の操作量が増加した状態が保持される。ここで、ステップ２２で原料と水の供給を停止しているが、改質器１４の内部には原料及び水蒸気が残留しており、この残留している原料及び水蒸気によって改質反応が進行し、一酸化炭素も含んだ水素含有ガスが生成される。そして、水素生成器８内の水素含有ガスが、改質器１４内に残留する水の蒸発に伴い水素生成器８より送出される。水素生成器８より送出された水素含有ガスは、バイパス経路１２を経由して、燃焼器２に供給され、燃焼される。そして、水素生成器８からの水素含有ガスが、燃焼器２へ供給されなくなると、消火することになる。すなわち、燃焼器２で燃焼が継続している間は、改質器１４からＣＯ除去器１５へ水素含有ガスが供給されており、酸化ガス供給器２３によって供給される空気により、発熱反応であるＣＯの選択酸化反応や水素の酸化反応が進行する。 And until the extinction of the combustor 2 is detected in step 24, the state in which the operation amount of the oxidizing gas supply device 23 is increased is maintained. Here, the supply of the raw material and water is stopped in step 22, but the raw material and water vapor remain inside the reformer 14, and the reforming reaction proceeds with the remaining raw material and water vapor. Then, a hydrogen-containing gas containing carbon monoxide is generated. The hydrogen-containing gas in the hydrogen generator 8 is sent from the hydrogen generator 8 as the water remaining in the reformer 14 evaporates. The hydrogen-containing gas delivered from the hydrogen generator 8 is supplied to the combustor 2 via the bypass path 12 and burned. When the hydrogen-containing gas from the hydrogen generator 8 is no longer supplied to the combustor 2, the fire is extinguished. That is, while combustion is continued in the combustor 2, the hydrogen-containing gas is supplied from the reformer 14 to the CO remover 15, and an exothermic reaction is caused by the air supplied by the oxidizing gas supplier 23. The selective oxidation reaction of CO and the oxidation reaction of hydrogen proceed.
　そこで、ステップ２４で消火が検知されると、ステップ２５において制御器１３は酸化ガス供給器２３の動作を停止する。 Therefore, when fire extinguishing is detected in step 24, the controller 13 stops the operation of the oxidizing gas supplier 23 in step 25.
　続いて、ステップ２６において、改質検出温度ＴＫが、設定温度Ｔ１まで低下すると、ステップ２７へと制御が進み、原料供給器４が動作して原料パージが実行される。 Subsequently, when the reforming detection temperature TK is lowered to the set temperature T1 in step 26, the control proceeds to step 27, the raw material supplier 4 is operated, and the raw material purge is executed.
　そして、水素生成器８内に滞留しているガスを置換できる十分な量の原料ガスが供給された後、ステップ２８で原料供給器４が停止される。 Then, after a sufficient amount of raw material gas capable of replacing the gas staying in the hydrogen generator 8 is supplied, the raw material supplier 4 is stopped in step 28.
　本実施の形態２では、上記のように、水供給器３及び原料供給器４を停止した後に、一酸化炭素も含んだ水素含有ガスが流通している間、選択酸化触媒の温度が発電運転時における制御温度よりも高くなるよう酸化ガス供給器２３の操作量を制御することによって、水素との酸化反応量が増加し、ＣＯ除去器１５の温度を発電運転時の温度以上にあげることが出来る。そのため、改質検出温度ＴＫが原料パージ可能な温度（Ｔ１）まで温度低下する間に、ＣＯ除去器１５内で結露が発生することを抑制することが出来る。 In the second embodiment, as described above, after the water supply device 3 and the raw material supply device 4 are stopped, while the hydrogen-containing gas containing carbon monoxide is flowing, the temperature of the selective oxidation catalyst is changed to the power generation operation. By controlling the operation amount of the oxidizing gas supply device 23 so as to be higher than the control temperature at the time, the amount of oxidation reaction with hydrogen increases, and the temperature of the CO remover 15 can be raised to a temperature higher than that during power generation operation. I can do it. Therefore, it is possible to suppress the occurrence of dew condensation in the CO remover 15 while the reforming detection temperature TK is lowered to the temperature (T1) at which the raw material can be purged.
　尚、ガス流路の一例は、上記実施の形態では、水素ガス供給経路９のＣＯ除去器１５からバイパス経路１２への分岐点Ｐまでの流路と、バイパス経路１２と、アノードオフガス供給経路１０のバイパス経路１２からの合流点Ｑから燃焼器２までの流路に相当する。また、燃焼検知器の一例は、フレームロッド２２に相当する。 An example of the gas flow path is the flow path from the CO remover 15 of the hydrogen gas supply path 9 to the branch point P to the bypass path 12, the bypass path 12, and the anode off-gas supply path 10 in the above embodiment. This corresponds to the flow path from the confluence point Q from the bypass path 12 to the combustor 2. An example of the combustion detector corresponds to the frame rod 22.
　又、本実施の形態２では、第２の制御の一例として、水供給器３及び原料供給器４を停止した後に、残留している原料及び水によって生成される水素含有ガスが流通している間、選択酸化触媒の温度が発電運転時における制御温度よりも高くなるように、酸化ガス供給器２３の操作量を停止指令直前よりも増加させて動作させる制御が行われていたが、このような制御に限らなくても良く、以下の変形例１に示すような制御であってもよく、要するに、燃料電池システムの発電停止後に、改質器より水素含有ガスが送出される期間において、選択酸化触媒の温度が、発電運転時の制御温度よりも高くなるよう酸化ガス供給器の操作量の制御が行われればよい。 In the second embodiment, as an example of the second control, the hydrogen-containing gas generated by the remaining raw material and water is circulated after the water supply device 3 and the raw material supply device 4 are stopped. During this time, control was performed such that the operation amount of the oxidizing gas supply device 23 was increased from immediately before the stop command so that the temperature of the selective oxidation catalyst became higher than the control temperature during the power generation operation. The control is not limited to such control, and may be control as shown in Modification 1 below. In short, after the power generation of the fuel cell system is stopped, it is selected during the period in which the hydrogen-containing gas is sent from the reformer. It is only necessary to control the amount of operation of the oxidizing gas supplier so that the temperature of the oxidation catalyst becomes higher than the control temperature during the power generation operation.
　第２の制御の他の例について、以下の変形例１において説明する。 Another example of the second control will be described in Modification 1 below.
　（変形例１）
　また、変形例１に係る燃料電池システムは、停止後、改質器より水素含有ガスが送出される期間は、停止後も反応ガス供給器からの反応ガスの供給を継続する期間を含む、ことを特徴とする。 (Modification 1)
In the fuel cell system according to Modification 1, the period in which the hydrogen-containing gas is sent from the reformer after the stop includes a period in which the supply of the reaction gas from the reaction gas supplier is continued even after the stop. It is characterized by.
　かかる構成により、実施の形態２の燃料電池システムに比べ、改質器からＣＯ除去器への水素含有ガスの供給が継続される時間が長くなるので、ＣＯ除去器の温度をより上げることが出来る。従って、改質器が原料パージ可能な温度になるまでの間に、ＣＯ除去器の温度が低下して結露が発生することを、実施の形態２の燃料電池システムよりも抑制することが出来る。 With this configuration, the time during which the supply of the hydrogen-containing gas from the reformer to the CO remover is continued is longer than in the fuel cell system of Embodiment 2, so that the temperature of the CO remover can be further increased. . Accordingly, it is possible to suppress the occurrence of dew condensation due to the temperature of the CO remover being lowered before the reformer reaches a temperature at which the raw material can be purged, as compared with the fuel cell system of the second embodiment.
　上記実施の形態２では、水供給器３と原料供給器４を停止後に酸化ガス供給器２３の操作量を増加させているが、本変形例では水供給と原料供給を継続しながら、酸化ガス供給器２３の操作量を増加させるように制御が行われる。 In the second embodiment, the operation amount of the oxidizing gas supply unit 23 is increased after the water supply unit 3 and the raw material supply unit 4 are stopped. In this modification, the oxidizing gas is supplied while continuing the water supply and the raw material supply. Control is performed so as to increase the operation amount of the feeder 23.
　図４は、この場合の制御フローを示す図である。図４に示すように、変形例１のフローでは、図３で示したステップ２２の代わりに、カソードガス供給器１１０を停止し、水供給器３及び原料供給器４の供給量の減少を開始するステップ２０１が設けられている。そして、ステップ２０１の次に、ステップ２３において酸化ガス供給器２３が制御され、酸化ガス（空気）供給量が停止指令直前よりも増加する。 FIG. 4 is a diagram showing a control flow in this case. As shown in FIG. 4, in the flow of the modified example 1, instead of step 22 shown in FIG. 3, the cathode gas supply device 110 is stopped and the supply amount of the water supply device 3 and the raw material supply device 4 starts to decrease. Step 201 is provided. Then, after step 201, the oxidizing gas supply device 23 is controlled in step 23, and the amount of oxidizing gas (air) supplied increases from immediately before the stop command.
　ステップ２３から所定時間経過すると、ステップ２０２において、水供給器３及び原料供給器４の動作が停止する。そして、上述した実施の形態２と同様に、水素生成器８内に残留した水素含有ガスの排出が終了すると、ステップ２４で燃焼器２の消火が検知される。 When a predetermined time has elapsed from step 23, in step 202, the operations of the water supply unit 3 and the raw material supply unit 4 are stopped. When the discharge of the hydrogen-containing gas remaining in the hydrogen generator 8 is completed, the fire extinguishing of the combustor 2 is detected in step 24 as in the second embodiment.
　このように、燃焼器２の消火が検知されると、ステップ２５において、酸化ガス供給器２３が停止される。 Thus, when the fire extinguishing of the combustor 2 is detected, in step 25, the oxidizing gas supply unit 23 is stopped.
　その後の制御は、上記と同様に、ステップ２６において、改質検出温度ＴＫがＴ１に達すると、ステップ２７で原料パージが行われる。そして、十分に原料パージが行われると、ステップ２８で原料供給器４が停止される。 In the subsequent control, when the reforming detection temperature TK reaches T1 in step 26, the raw material purge is performed in step 27 as described above. When the material purge is sufficiently performed, the material supply unit 4 is stopped in step 28.
　尚、この変形例１では、第２の制御の一例として、水供給器３と原料供給器４の操作量を除々に減少させて、ステップ２０２で停止させるよう制御が行われたが、ステップＳ２０２までは操作量を減少させずに、ステップ２０２で水供給器３と原料供給器４の動作を停止させるよう制御が行われても良い。この場合の制御フローが図５に示されている。図５に示す制御フローでは、図４に示すステップ２０１に代わり、ステップ２２０が設けられている。このステップ２２０では、カソードガス供給器１１０の動作の停止のみが行われる。そして、ステップ２３において、選択酸化触媒の温度が発電運転時における制御温度よりも高くなるように、酸化ガス供給器２３の操作量を、例えば停止指令直前（発電運転時）よりも増加させ、所定時間経過した後に、ステップ２０２で水供給器３及び原料供給器４の停止が行われる。ステップ２３からステップ２０２までの所定時間は、例えば、実施の形態１のＨ０等と設定することが出来る。 In the first modification, as an example of the second control, the operation amount of the water supply device 3 and the raw material supply device 4 is gradually decreased and stopped in step 202, but the control is performed in step S202. Until the operation amount is not reduced, control may be performed so as to stop the operations of the water supply unit 3 and the raw material supply unit 4 in step 202. The control flow in this case is shown in FIG. In the control flow shown in FIG. 5, step 220 is provided instead of step 201 shown in FIG. In this step 220, only the operation of the cathode gas supplier 110 is stopped. In step 23, the operation amount of the oxidizing gas supply device 23 is increased, for example, immediately before the stop command (during power generation operation) so that the temperature of the selective oxidation catalyst becomes higher than the control temperature during power generation operation. After the elapse of time, the water supply unit 3 and the raw material supply unit 4 are stopped in step 202. The predetermined time from step 23 to step 202 can be set, for example, as H0 in the first embodiment.
　（変形例２）
　実施の形態１では、第１の制御の一例として、停止指令の前に、選択酸化触媒の温度が発電運転時における制御温度よりも高くなるように酸化ガス供給器２３の操作量を制御することにより、ＣＯ除去器１５の温度を上げている。一方、実施の形態２では、第２の制御の一例として、停止指令の後、一酸化炭素を含んだ水素含有ガスが流通している間、選択酸化触媒の温度が、その制御温度よりも高くなるように酸化ガス供給器２３の操作量を制御することにより、ＣＯ除去器１５の温度を上げている。これら第１の制御と第２の制御を組み合わせて、停止指令の前後において、選択酸化触媒の温度が、発電運転時における制御温度よりも高くなるように酸化ガス供給器２３の操作量を増加させるように制御が行われても良い。 (Modification 2)
In the first embodiment, as an example of the first control, the operation amount of the oxidizing gas supplier 23 is controlled before the stop command so that the temperature of the selective oxidation catalyst becomes higher than the control temperature during the power generation operation. Thus, the temperature of the CO remover 15 is increased. On the other hand, in the second embodiment, as an example of the second control, the temperature of the selective oxidation catalyst is higher than the control temperature while the hydrogen-containing gas containing carbon monoxide is flowing after the stop command. Thus, the temperature of the CO remover 15 is raised by controlling the operation amount of the oxidizing gas supply device 23. By combining the first control and the second control, the operation amount of the oxidizing gas supplier 23 is increased before and after the stop command so that the temperature of the selective oxidation catalyst becomes higher than the control temperature during the power generation operation. Control may be performed as described above.
　図６は、変形例２の制御フロー図である。図６に示すステップ２１１からステップ２１６は、実施の形態１のステップ１からステップ６と同様である。そして、ステップ２１６の後、本変形例２では、ステップ２１７において、実施の形態１と異なり、酸化ガス供給器２３の動作が停止されず、酸化ガス供給器２３の操作量が増加した状態が保持され、水供給器３、原料供給器４及びカソードガス供給器１１０の動作が停止される。 FIG. 6 is a control flow diagram of Modification 2. Steps 211 to 216 shown in FIG. 6 are the same as steps 1 to 6 in the first embodiment. Then, after Step 216, in Modification 2, unlike Step 1, in Step 217, the operation of the oxidizing gas supplier 23 is not stopped and the state in which the operation amount of the oxidizing gas supplier 23 is increased is maintained. Then, the operations of the water supply unit 3, the raw material supply unit 4 and the cathode gas supply unit 110 are stopped.
　次に、水素生成器８内に残留している水素含有ガスの排出が終了して、ステップ２１８において、燃焼器２の消火が検知されると、ステップ２１９において酸化ガス供給器２３の動作が停止される。 Next, when the discharge of the hydrogen-containing gas remaining in the hydrogen generator 8 is completed, and the fire extinguishing of the combustor 2 is detected in step 218, the operation of the oxidizing gas supply device 23 is stopped in step 219. Is done.
　続いて、ステップ２２０において、改質検出温度ＴＫがＴ１まで低下すると、ステップ２２１において、原料パージが実行される。そして、十分に原料パージが行われると、ステップ２２２で、原料供給器４の動作が停止される。 Subsequently, when the reforming detection temperature TK is reduced to T1 in step 220, the raw material purge is executed in step 221. When the material purge is sufficiently performed, the operation of the material supplier 4 is stopped in step 222.
　尚、本変形例２では、ステップ２１７において、水供給器３及び原料供給器４を停止させているが、変形例１で述べたように、水供給器３及び原料供給器４の操作量を除々に減少させて停止させるように制御が行われても良い。この制御について図６を用いて説明すると、ステップ２１７において、カソードガス供給器１１０の停止とともに、水供給器３及び原料供給器４の操作量が減少されるように制御が行われる。その後、水供給器３及び原料供給器４が完全に停止し、ステップ２１８において燃焼器２の消火が検知されると酸化ガス供給器２３が停止される。 In the second modification, the water supply device 3 and the raw material supply device 4 are stopped in step 217. However, as described in the first modification, the operation amounts of the water supply device 3 and the raw material supply device 4 are changed. Control may be performed so as to gradually decrease and stop. This control will be described with reference to FIG. 6. In step 217, the control is performed so that the operation amount of the water supply unit 3 and the raw material supply unit 4 is reduced as the cathode gas supply unit 110 is stopped. Thereafter, the water supply device 3 and the raw material supply device 4 are completely stopped, and when the fire extinguishing of the combustor 2 is detected in step 218, the oxidizing gas supply device 23 is stopped.
　又、本実施の形態２及び変形例１では、停止後、改質器より水素含有ガスが送出される期間として、反応ガス供給器を停止した後に、改質器内に残留した反応ガスから生成された水素含有ガスがＣＯ除去器に送出される期間を含む場合、燃焼検知器で燃焼器の燃焼が検知されている期間を含む場合、反応ガス供給器からの反応ガスの供給を継続する期間を含む場合について説明したが、これらは例示である。すなわち、停止後、改質器より水素含有ガスが送出される期間であればいずれの期間であってもよい。 In Embodiment 2 and Modification 1, after the stop, the hydrogen-containing gas is delivered from the reaction gas remaining in the reformer after the reaction gas supply device is stopped as a period for sending the hydrogen-containing gas from the reformer. A period in which the reaction gas supply from the reaction gas supply device is continued when a combustion detector includes a period in which combustion of the combustor is detected, including a period during which the hydrogen-containing gas is delivered to the CO remover However, these are merely examples. That is, any period may be used as long as the hydrogen-containing gas is delivered from the reformer after the stop.
　又、本実施の形態２及び変形例１、２では、酸化ガス供給器２３の操作量を増加させた後、燃焼器２の消火が検知されるまでの間（つまり、改質器１４より水素含有ガスが送出されなくなるまで）、増加された操作量を維持している。しかしながら、改質器１４より水素含有ガスが送出されなくなる前に、酸化ガス供給器２３の操作量の増加制御を停止してもよい。ようするに、改質器１４より水素含有ガスが送出される期間の少なくとも一部の期間において酸化ガス供給器２３の操作量を増加させる制御が行われても良い。 In Embodiment 2 and Modifications 1 and 2, the amount of operation of the oxidant gas supply device 23 is increased and until the fire extinguishing of the combustor 2 is detected (that is, the reformer 14 supplies hydrogen. The increased amount of operation is maintained until the contained gas is no longer delivered. However, the increase control of the operation amount of the oxidizing gas supply unit 23 may be stopped before the hydrogen-containing gas is not sent from the reformer 14. In this way, control for increasing the operation amount of the oxidizing gas supply device 23 may be performed in at least a part of the period in which the hydrogen-containing gas is sent from the reformer 14.
　又、本実施の形態２及び変形例１、２では、燃焼器２の消火が検知されると（つまり、改質器１４より水素含有ガスが送出されなくなると）酸化ガス供給器２３を停止させているが、停止させなくても良い。但し、水素含有ガスのＣＯ除去器１５への流入が停止した後も酸化ガス供給器２３から空気を供給させると、酸化反応の量が低減し、さらに供給空気による冷却効果によって、発熱反応による昇温効果が低減する場合があるため、燃焼器２の消火が検知された場合、酸化ガス供給器２３を停止した方が好ましい。 In Embodiment 2 and Modifications 1 and 2, when the fire extinguishing of the combustor 2 is detected (that is, when the hydrogen-containing gas is no longer sent from the reformer 14), the oxidizing gas supply device 23 is stopped. However, it does not have to be stopped. However, if air is supplied from the oxidizing gas supply unit 23 even after the flow of the hydrogen-containing gas into the CO remover 15 is stopped, the amount of the oxidation reaction is reduced, and the cooling effect by the supply air further increases the temperature by the exothermic reaction. Since the temperature effect may be reduced, it is preferable to stop the oxidant gas supply device 23 when extinguishing the combustor 2 is detected.
　（実施の形態３）
　以下、実施の形態３における燃料電池システムについて説明する。 (Embodiment 3)
Hereinafter, the fuel cell system according to Embodiment 3 will be described.
　本実施の形態３の燃料電池システムは、実施の形態１の燃料電池システムと基本的な構成は同じであるが、実施の形態１と異なり、ＣＯ除去器１５にヒーターが設けられている。そのため、本相違点を中心に説明する。尚、実施の形態１と同様の構成については同一の符号を付している。 The basic configuration of the fuel cell system of the third embodiment is the same as that of the fuel cell system of the first embodiment, but unlike the first embodiment, the CO remover 15 is provided with a heater. Therefore, this difference will be mainly described. In addition, the same code | symbol is attached | subjected about the structure similar to Embodiment 1. FIG.
　図７は、本実施の形態３の燃料電池システムの構成図である。図７に示すように、本実施の形態３の燃料電池システムには、ＣＯ除去器１５を加熱するためのヒーター３１が設けられている。また、実施の形態１での制御に加えて、選択酸化温度検出器２５による検出温度に基づいてヒーター３１のオン・オフの制御も行う制御器３０が設けられている。 FIG. 7 is a configuration diagram of the fuel cell system according to the third embodiment. As shown in FIG. 7, the fuel cell system of Embodiment 3 is provided with a heater 31 for heating the CO remover 15. In addition to the control in the first embodiment, a controller 30 is also provided that also controls the heater 31 on and off based on the temperature detected by the selective oxidation temperature detector 25.
　図８は、本実施の形態３の燃料電池システムの停止方法の制御フローを示す図である。図８に示すように、本実施の形態３では、ステップ８において、改質検出温度ＴＫがＴ１に達していない場合、制御はステップ３１へと進む。尚、実施の形態１と同様の制御については、同一の符号を付している。 FIG. 8 is a diagram showing a control flow of the fuel cell system stopping method of the third embodiment. As shown in FIG. 8, in the third embodiment, if the reforming detection temperature TK does not reach T1 in step 8, the control proceeds to step 31. In addition, the same code | symbol is attached | subjected about the control similar to Embodiment 1. FIG.
　ステップ３１で、選択酸化温度検出器２５によって検出される選択酸化検出温度ＴＳが、予め設定されている温度Ｔ２より高いか否かが判定される。そして、選択酸化検出温度ＴＳが、設定温度Ｔ２以下である場合、制御器３０は、ステップ３２においてヒーター３１がオン状態になるように制御を行う。ここで、温度Ｔ２は、ヒーター３１の応答性を考慮して、結露発生温度よりも高く設定されている。 In step 31, it is determined whether or not the selective oxidation detection temperature TS detected by the selective oxidation temperature detector 25 is higher than a preset temperature T2. When the selective oxidation detection temperature TS is equal to or lower than the set temperature T2, the controller 30 performs control so that the heater 31 is turned on in step 32. Here, the temperature T2 is set higher than the dew condensation occurrence temperature in consideration of the responsiveness of the heater 31.
　一方、ステップ３１で、選択酸化検出温度ＴＳが設定温度Ｔ２よりも高い場合には、制御はステップ３３へと進み、ヒーター３１がオフ状態になるように制御が行われる。尚、ステップ３２、３３の後、制御はステップ８へと戻り、改質検出温度ＴＫがＴ１に達するまでの間、ステップ３１、３２、３３が繰り返される。そして、改質検出温度ＴＫがＴ１まで温度が低下すると、ステップ９において原料パージが行われる。尚、ヒーター３１がオン状態になっている場合、ステップ９における原料パージ時には、オフ状態にされる。 On the other hand, when the selective oxidation detection temperature TS is higher than the set temperature T2 in step 31, the control proceeds to step 33, and the control is performed so that the heater 31 is turned off. After steps 32 and 33, control returns to step 8, and steps 31, 32, and 33 are repeated until the reforming detection temperature TK reaches T1. Then, when the temperature of the reforming detection temperature TK decreases to T1, the raw material purge is performed in Step 9. When the heater 31 is on, the raw material is purged at step 9 and is turned off.
　このように、本実施の形態３では、改質検出温度ＴＫが原料パージ可能な温度Ｔ１に達するまでに、ヒーター３１を制御して、ＣＯ除去器１５の温度が結露温度以下にならないように出来るため、実施の形態１及び実施の形態２、それぞれの変形例における燃料電池システムに比べ、ＣＯ除去器１５における結露の発生をより抑制することが可能になる。 As described above, in the third embodiment, the heater 31 is controlled until the reforming detection temperature TK reaches the temperature T1 at which the raw material can be purged, so that the temperature of the CO remover 15 does not fall below the dew condensation temperature. Therefore, it is possible to further suppress the occurrence of condensation in the CO remover 15 as compared with the fuel cell systems in the first and second embodiments and the respective modifications.
　次に、本実施の形態３の燃料電池システムについて、実施例に基づいて詳細に説明する。 Next, the fuel cell system of Embodiment 3 will be described in detail based on examples.
　（実施例１）
　図８の燃料電池システムの停止方法の制御フローにおいて、Ｔ１を１５０℃、Ｔ２を１２０℃、Ｈ０を１０分に設定したプログラムを組んで燃料電池システムの停止処理を行った。 Example 1
In the control flow of the stopping method of the fuel cell system of FIG. 8, the stopping process of the fuel cell system was performed by assembling a program in which T1 was set to 150 ° C., T2 was set to 120 ° C., and H0 was set to 10 minutes.
　図９は、改質検出温度ＴＫ、及び選択酸化検出温度ＴＳの経時変化のグラフを示す図である。図９に示すように、停止指令（発電停止）前の１０分間に、選択酸化触媒の温度が発電運転時における制御温度よりも高くなるように酸化ガス供給器２３の操作量を直前の操作量よりも増量したため、発熱反応である選択酸化反応が促進され、ＣＯ除去器１５の温度が２００℃程度まで上昇した。そして、停止指令によって改質器１４の運転及び燃料電池１００の発電が停止されると、改質器１４及びＣＯ除去器１５の温度が低下する。 FIG. 9 is a graph showing changes over time in the reforming detection temperature TK and the selective oxidation detection temperature TS. As shown in FIG. 9, during the 10 minutes before the stop command (power generation stop), the operation amount of the oxidizing gas supplier 23 is set to the operation amount immediately before so that the temperature of the selective oxidation catalyst becomes higher than the control temperature during the power generation operation. Therefore, the selective oxidation reaction, which is an exothermic reaction, was promoted, and the temperature of the CO remover 15 rose to about 200 ° C. When the operation of the reformer 14 and the power generation of the fuel cell 100 are stopped by the stop command, the temperatures of the reformer 14 and the CO remover 15 are lowered.
　そして、経過時間が４時間に達する前に、ＣＯ除去器１５の温度が低下して１２０℃になり、ヒーター３１のＯＮ―ＯＦＦ制御が開始された。 And before the elapsed time reached 4 hours, the temperature of the CO remover 15 decreased to 120 ° C., and the ON / OFF control of the heater 31 was started.
　ヒーター３１は原料パージ開始までに１時間５５分の間、ＯＮ－ＯＦＦ制御され、ヒーターで消費された電力量は５８７．５Ｗｈであった。酸化ガス供給器２３の空気供給量が増量された１０分間における酸化ガス（空気）の供給量の増量分は４ＮＬであった。大気中の酸素濃度を２１％とすると、消費された水素量は０．８４ＮＬであり、燃焼熱量としては２１．３ｋＪに相当する。１Ｗｈは３．２ｋＪであるので、燃焼熱量は５．９Ｗｈ相当となる。 The heater 31 was ON-OFF controlled for 1 hour 55 minutes before starting the material purge, and the amount of power consumed by the heater was 587.5 Wh. The increase in the supply amount of the oxidizing gas (air) during 10 minutes when the air supply amount of the oxidizing gas supply unit 23 was increased was 4 NL. If the oxygen concentration in the atmosphere is 21%, the amount of consumed hydrogen is 0.84 NL, which corresponds to 21.3 kJ as the amount of combustion heat. Since 1 Wh is 3.2 kJ, the amount of combustion heat is equivalent to 5.9 Wh.
　（比較例１）
　比較例１では、本実施の形態１で述べた停止方法のフローを用いず、図８のステップ５以降のみを実行し、Ｔ１を１５０℃、Ｔ２を１２０℃としたプログラムを組んで停止処理が行われた。 (Comparative Example 1)
In the first comparative example, the flow of the stopping method described in the first embodiment is not used, only the step 5 and the subsequent steps in FIG. 8 are executed, and the stopping process is performed by setting a program in which T1 is 150 ° C. and T2 is 120 ° C. It was conducted.
　図１０は、改質検出温度ＴＫ及び選択酸化検出温度ＴＳの経時変化グラフを示す図である。ヒーター３１は原料パージ開始までに２時間５分の間、ＯＮ－ＯＦＦ制御され、ヒーター３１で消費された電力量は６１２．５Ｗｈであった。 FIG. 10 is a graph showing a temporal change graph of the reforming detection temperature TK and the selective oxidation detection temperature TS. The heater 31 was ON-OFF controlled for 2 hours and 5 minutes before starting the raw material purge, and the amount of power consumed by the heater 31 was 612.5 Wh.
　実施例１で消費されたエネルギーは５８７．５＋５．９＝５９３．４Ｗｈであり、比較例１よりも低くなっている。比較例１で用いるヒーター３１による加温は、ＣＯ除去器１５の外部からの加熱であるため、ＣＯ除去器１５の内部で触媒上での燃焼反応熱を直接利用する実施例１よりロスが大きいことがわかる。また、燃料電池システムは５０００回程度の起動停止を行うため、（６１２．５－５９３．４）Ｗｈ×５０００＝１１４．５ｋＷｈのエネルギーを削減できることになる。 The energy consumed in Example 1 is 587.5 + 5.9 = 593.4 Wh, which is lower than that in Comparative Example 1. Since the heating by the heater 31 used in Comparative Example 1 is heating from the outside of the CO remover 15, the loss is larger than that in Example 1 in which the combustion reaction heat on the catalyst is directly used inside the CO remover 15. I understand that. In addition, since the fuel cell system is started and stopped about 5000 times, energy of (612.5−593.4) Wh × 5000 = 114.5 kWh can be reduced.
　以上のように、本実施の形態１における燃料電池システムの停止方法の有用性が分かった。 As described above, the usefulness of the method for stopping the fuel cell system according to Embodiment 1 has been found.
　尚、本実施の形態３では、実施の形態１で説明した第１の制御にヒーター３１の制御を加えたが、第１の制御の代わりに、実施の形態２、変形例１で説明したような第２の制御にヒーター３１の制御を加えても良い。また、実施の形態２の変形例２で説明したような第１の制御と第２の制御の双方を行う制御にヒーター３１の制御を加えても良い。 In the third embodiment, the control of the heater 31 is added to the first control described in the first embodiment, but instead of the first control, as described in the second embodiment and the first modification. The control of the heater 31 may be added to the second control. In addition, the control of the heater 31 may be added to the control that performs both the first control and the second control as described in the second modification of the second embodiment.
　又、上記実施の形態１～３における水素生成器８には、改質器１４とＣＯ除去器１５が設けられていたが、改質器１４とＣＯ除去器１５の間に、シフト反応が行われる変成器が設けられていてもよい。この変成器において、約１５０～３００℃でシフト反応が行われる。尚、変成器にも、上記実施の形態３のＣＯ除去器１５のようにヒーターが設けられていても良い。このヒーターとしては、ＣＯ除去器１５のヒーターと一体のものでもよく、別々に設けられていても良い。 The hydrogen generator 8 in the first to third embodiments is provided with the reformer 14 and the CO remover 15. However, a shift reaction takes place between the reformer 14 and the CO remover 15. A transformer may be provided. In this transformer, the shift reaction takes place at about 150-300 ° C. The transformer may also be provided with a heater like the CO remover 15 of the third embodiment. This heater may be integrated with the heater of the CO remover 15 or may be provided separately.
　又、開閉弁の一例は、上記実施の形態の開閉弁１１ａ及び開閉弁１１ｂに相当するが、開閉弁を２つ設ける代わりに、水素ガス供給経路９のバイパス経路１２への分岐点Ｐに三方弁を備えた構成としてもよい。要するに、水素生成器８から排出されたガスの供給先を、燃料電池１００側若しくはバイパス経路１２側のいずれかに切り替えることが可能でありさえすればよい。 An example of the on-off valve corresponds to the on-off valve 11a and the on-off valve 11b of the above embodiment, but instead of providing two on-off valves, three points are provided at the branch point P of the hydrogen gas supply path 9 to the bypass path 12. It is good also as a structure provided with the valve. In short, it is only necessary to switch the supply destination of the gas discharged from the hydrogen generator 8 to either the fuel cell 100 side or the bypass path 12 side.
　尚、上記実施の形態１～３及びその変形例における燃料電池システムでは、選択酸化温度検出器２５を設けて、その検出温度をチェックしながら、酸化触媒の制御温度が発電運転時の制御温度よりも高くなるよう酸化ガス供給器２３の操作量を増加させる形態を採用している。 In the fuel cell systems according to Embodiments 1 to 3 and the modifications thereof, the selective oxidation temperature detector 25 is provided, and the control temperature of the oxidation catalyst is higher than the control temperature during the power generation operation while checking the detected temperature. The operation amount of the oxidizing gas supply device 23 is increased so as to be higher.
　しかしながら、本形態に限定されるものではなく、選択酸化温度検出器２５を設けずに、ＣＯ除去器への水素含有ガス供給量に対する酸化ガスの供給量が、発電運転時よりも多くなるよう酸化ガス供給器２３の操作量を制御する形態であっても構わない。 However, the present invention is not limited to this embodiment, and the oxidizing gas supply amount with respect to the hydrogen-containing gas supply amount to the CO remover is oxidized so as to be larger than that in the power generation operation without providing the selective oxidation temperature detector 25. The operation amount of the gas supply device 23 may be controlled.
　例えば、ＣＯ除去器１５への水素含有ガス供給量に比例相関する物理量に対する酸化ガスの供給量が増加するよう酸化ガス供給器２３の操作量が制御される。上記物理量としては、例えば、改質器１４への原料供給量、改質器１４への水蒸気供給量、燃料電池システムの発電量等が挙げられる。 For example, the operation amount of the oxidizing gas supply unit 23 is controlled so that the supply amount of the oxidizing gas with respect to the physical quantity proportional to the supply amount of the hydrogen-containing gas to the CO remover 15 increases. Examples of the physical quantity include a raw material supply amount to the reformer 14, a water vapor supply amount to the reformer 14, and a power generation amount of the fuel cell system.
　つまり、ＣＯ除去器１５への水素含有ガス供給量に対する酸化ガスの供給量が、発電運転時よりも多くなるよう酸化ガス供給器２３の操作量を制御するよう構成されていれば、いずれの形態であっても構わない。 That is, any configuration is possible as long as the operation amount of the oxidant gas supply unit 23 is controlled so that the supply amount of the oxidant gas relative to the hydrogen-containing gas supply amount to the CO remover 15 is larger than that during power generation operation. It does not matter.
　又、上記実施の形態１～３及びその変形例における燃料電池システムでは、酸化ガス供給器２３の操作量の増加制御中において、連続的に酸化ガス供給器２３が動作する形態を採用しているが、間欠的に動作する形態を採用しても構わない。 Further, the fuel cell system according to Embodiments 1 to 3 and the modification thereof employs a mode in which the oxidizing gas supply device 23 operates continuously during the increase control of the operation amount of the oxidizing gas supply device 23. However, a mode that operates intermittently may be adopted.
　また、実施の形態１の図２、実施の形態２の図３、変形例２の図６、及び実施の形態３の図８の制御フローでは、開閉弁１１ａを開とし、開閉弁１１ｂを閉とするステップの後に、水供給器３及び原料供給器４を停止させるステップが設けられているが、順番が逆であってもよく、これらのステップが同時に行われても良い。これらのステップは、実施の形態１の図２で説明すると、ステップ６とステップ７に相当する。 In the control flow of FIG. 2 of the first embodiment, FIG. 3 of the second embodiment, FIG. 6 of the second modification, and FIG. 8 of the third embodiment, the on-off valve 11a is opened and the on-off valve 11b is closed. After the step, the step of stopping the water supply device 3 and the raw material supply device 4 is provided, but the order may be reversed, and these steps may be performed simultaneously. These steps correspond to Step 6 and Step 7 when described with reference to FIG. 2 of the first embodiment.
　また、上記実施の形態１～３では、停止制御時に、燃焼器２で燃焼が行われているが、燃焼が行われていなくても良い。但し、燃料電池システムから原料ガスを排出するときには、希釈をすることが望ましいため、燃焼器２の空気供給器２０は動作させた方が好ましい。 In Embodiments 1 to 3 described above, combustion is performed in the combustor 2 at the time of stop control, but the combustion may not be performed. However, since it is desirable to dilute the raw material gas from the fuel cell system, it is preferable to operate the air supply unit 20 of the combustor 2.
　また、上記実施の形態１～３及び実施例１では、必ず酸化ガス供給器２３による酸化ガス供給量が増量されていたが、ＣＯ除去器１５の温度が所定温度（Ｔ３）以上である場合には、改質器１４の温度が原料供給開始温度Ｔ１になるまでの間に、ＣＯ除去器１５での結露が発生する可能性が低いとして、酸化ガス供給量を増量しないような制御フローを構成してもよい。更に、酸化ガス供給量を増量後、ＣＯ除去器１５の温度が所定温度（Ｔ３）以上となった場合にも、酸化ガス供給量を増量前の状態に戻すような制御フローを構成してもよい。 In Embodiments 1 to 3 and Example 1, the amount of oxidizing gas supplied by the oxidizing gas supplier 23 is always increased. However, when the temperature of the CO remover 15 is equal to or higher than a predetermined temperature (T3). Constitutes a control flow that does not increase the supply amount of the oxidizing gas, assuming that the possibility of dew condensation in the CO remover 15 is low before the temperature of the reformer 14 reaches the raw material supply start temperature T1. May be. Further, even if the temperature of the CO remover 15 becomes equal to or higher than the predetermined temperature (T3) after increasing the oxidizing gas supply amount, a control flow may be configured to return the oxidizing gas supply amount to the state before the increase. Good.
　このＴ３を用いた制御を実施の形態１に適用した場合の具体例について図２の制御フローを用いて説明する。図１１は、このような制御を示すフロー図である。図１１の制御フローに示すように、図２の制御フローのステップ２とステップ３の間にＴＳ＜Ｔ３を判定するステップ３４が挿入され、ＴＳがＴ３未満の場合には、制御はステップ３へと進み、酸化ガス供給器２３の操作量を増加するよう制御される。より具体的には、ＣＯ除去器１５への水素含有ガスの供給量に対する酸化ガスの供給量が、酸化ガス供給器２３の操作量の増加制御が開始される前（ステップ２でＹｅｓになる前）より増量するよう酸化ガス供給器の操作量が制御される。一方、ステップ３４においてＴＳがＴ３以上となった場合には、ステップ３５において酸化ガス供給器２３の操作量の増加制御が開始される前（ステップ２でＹｅｓになる前）の操作量になるように酸化ガス供給器２３が制御され、ステップ３４に戻り、ＴＳがＴ３に未満になる迄、この状態が継続される。尚、ステップ３において酸化ガス供給器２３の操作量が増加された後、ステップ３４でＴＳがＴ３未満と判断されている間は、ステップ３において、操作量を増加した状態が維持されることになる。このＴ３としては、例えば、２００℃と設定し得る。 A specific example when the control using T3 is applied to the first embodiment will be described with reference to the control flow of FIG. FIG. 11 is a flowchart showing such control. As shown in the control flow of FIG. 11, step 34 for determining TS <T3 is inserted between step 2 and step 3 of the control flow of FIG. 2, and if TS is less than T3, control goes to step 3 Then, control is performed so as to increase the operation amount of the oxidizing gas supply unit 23. More specifically, the supply amount of the oxidizing gas with respect to the supply amount of the hydrogen-containing gas to the CO remover 15 is started before the increase control of the operation amount of the oxidizing gas supply device 23 is started (before Yes in Step 2). ) The operating amount of the oxidizing gas supply device is controlled so as to increase the amount. On the other hand, when TS becomes equal to or greater than T3 in step 34, the operation amount becomes the operation amount before the increase control of the operation amount of the oxidizing gas supply device 23 is started in step 35 (before becoming Yes in step 2). Then, the oxidizing gas supplier 23 is controlled, and the process returns to step 34, and this state is continued until TS becomes less than T3. In addition, after the operation amount of the oxidizing gas supply device 23 is increased in Step 3, while the TS is determined to be less than T3 in Step 34, the state in which the operation amount is increased is maintained in Step 3. Become. This T3 can be set to 200 ° C., for example.
　このように、実施の形態１の図２、実施の形態３及び実施例１の図８の制御フローでは、操作量が増量されていた期間であるＨ０について、上記Ｔ３を用いた制御を適用し得るが、実施の形態２及びその変形例における図３～図５の制御フローでは、制御器１３が、停止指令を出力後、燃焼器２が消化検知されるまでの期間について、上記Ｔ３を用いた制御を適用してもよい。また、実施の形態２の変形例２における図６の制御フローでは、燃料電池システムの発電停止に先行して、酸化ガス供給器の操作量の増加制御を開始してから（ステップ２でＹｅｓになってから）、燃焼器２が消化検知されるまでの期間について、上記Ｔ３を用いた制御を適用してもよい。 As described above, in the control flow of FIG. 2 of the first embodiment, the third embodiment, and FIG. 8 of the first embodiment, the control using the T3 is applied to H0 that is the period during which the operation amount is increased. However, in the control flow of FIGS. 3 to 5 in the second embodiment and its modification, T3 is used for the period from when the controller 13 outputs a stop command until the combustor 2 is detected for digestion. You may apply the control you had. Further, in the control flow of FIG. 6 in the second modification of the second embodiment, the control of increasing the operation amount of the oxidizing gas supplier is started prior to the stop of power generation of the fuel cell system (Yes in step 2). The control using T3 may be applied to the period until the combustor 2 is detected for digestion.
　また、上記実施の形態１～３及び実施例１では、酸化ガス（空気）の供給量を増加させているが、酸化ガス（空気）の供給量に上限を設けてもよい。熱暴走開始温度よりも低い温度に選択酸化上限温度を別途設け、選択酸化検出温度が上限温度以上になった場合は、酸化ガス（空気）の供給量を減少させたりすることにより、熱暴走を防ぐことができる。 In Embodiments 1 to 3 and Example 1, the supply amount of the oxidizing gas (air) is increased. However, an upper limit may be set for the supply amount of the oxidizing gas (air). If a selective oxidation upper limit temperature is separately provided at a temperature lower than the thermal runaway start temperature, and the selective oxidation detection temperature exceeds the upper limit temperature, thermal runaway may be caused by reducing the supply amount of oxidizing gas (air). Can be prevented.
　尚、上記実施の形態で用いられる触媒に限らなくてもよく、例えば、改質触媒にＲｕ系の触媒を用いても良い。但し、触媒種によって冷却条件が異なり、例えば、改質触媒のＲｕ触媒は、炭素析出が発生しにくい等の使い勝手の良さから、特に、家庭用燃料電池の水素生成装置には広く採用されているが、コストが高くなる。一方、上記実施の形態で用いられているＮｉ触媒は低コストで入手可能であるが、Ｒｕ触媒に比べ炭素析出しやすいので、原料を用いた装置内のパージ（置換）が可能な温度はＲｕ触媒より低くなる。パージ可能な温度の上限温度は、触媒種によって異なっており、Ｒｕ触媒では４００～５００℃程度、Ｎｉ触媒では３００～４００℃程度である。 Note that the catalyst is not limited to the catalyst used in the above embodiment. For example, a Ru-based catalyst may be used as the reforming catalyst. However, the cooling conditions differ depending on the type of catalyst. For example, the reforming catalyst Ru catalyst is widely used especially for hydrogen generators for household fuel cells because of its ease of use, such as the difficulty of carbon deposition. However, the cost is high. On the other hand, the Ni catalyst used in the above embodiment can be obtained at a low cost. However, since it is easier to deposit carbon compared to the Ru catalyst, the temperature at which purging (substitution) in the apparatus using the raw material is possible is Ru. Lower than the catalyst. The upper limit of the purging temperature varies depending on the catalyst type, and is about 400 to 500 ° C. for the Ru catalyst and about 300 to 400 ° C. for the Ni catalyst.
　又、水素生成装置の各反応器で用いられる触媒は、装置の構成によって使用温度及び使用量が異なり、結露が開始する温度も異なるので、停止時の冷却状況が相違する。このように、触媒種によっても改質器、及び変成器の冷却条件が異なり、装置の構成によっても温度低下の状況が異なるので、装置毎に適切なＴ１～Ｔ３の基準値を用いることによって、停止時の結露防止に費やされるエネルギーを抑制することが可能となる。 In addition, the catalyst used in each reactor of the hydrogen generator has different operating temperatures and amounts depending on the configuration of the apparatus, and the temperature at which condensation starts is also different. As described above, the cooling conditions of the reformer and the transformer are different depending on the catalyst type, and the temperature drop state is also different depending on the configuration of the apparatus. Therefore, by using an appropriate reference value of T1 to T3 for each apparatus, It is possible to suppress energy spent for preventing condensation at the time of stopping.
　本発明の燃料電池システム及び燃料電池システムの停止方法は、パージ動作が実行されるまでの期間において、従来よりも省エネルギー性を向上しながら、ＣＯ除去器での結露を抑制することが可能になり、家庭用または業務用の燃料電池システム等として有用である。 The fuel cell system and the fuel cell system stopping method according to the present invention can suppress dew condensation in the CO remover while improving energy saving than before in the period until the purge operation is performed. It is useful as a fuel cell system for home use or business use.
　１　燃料改質装置
　２　燃焼器
　３　水供給器
　４　原料供給器
　５　吸着脱硫器
　６　ガスインフラライン
　８　水素生成器
　９　水素ガス供給経路
　１０　アノードオフガス供給経路
　１１ａ、１１ｂ　開閉弁
　１２　バイパス経路
　１３　制御器
　１４　改質器
　１５　ＣＯ除去器
　２０　空気供給器
　２１　イグナイター
　２２　フレームロッド
　２３　酸化ガス供給器
　２４　改質温度検出器
　２５　選択酸化温度検出器
　３１　ヒーター
　１００　燃料電池
　１１０　カソードガス供給器 DESCRIPTION OF SYMBOLS 1 Fuel reformer 2 Combustor 3 Water supply device 4 Raw material supply device 5 Adsorption desulfurization device 6 Gas infrastructure line 8 Hydrogen generator 9 Hydrogen gas supply route 10 Anode off- gas supply route 11a, 11b On-off valve 12 Bypass route 13 Controller 14 Reformer 15 CO remover 20 air supplier 21 igniter 22 flame rod 23 oxidizing gas supplier 24 reforming temperature detector 25 selective oxidation temperature detector 31 heater 100 fuel cell 110 cathode gas supplier

Claims (6)

  1. 　原料を用いて水素含有ガスを生成させる改質触媒を有する改質器、前記水素含有ガス中に含まれる一酸化炭素を酸化反応により低減させるための酸化触媒を有するＣＯ除去器、及び前記ＣＯ除去器に酸化ガスを供給する第１の酸化ガス供給器を備える水素生成装置と、
    　前記水素生成装置から供給される水素含有ガスを用いて発電を行う燃料電池と、
    　制御器とを備える燃料電池システムであって、
    　前記制御器は、
    　前記燃料電池システムの発電運転を停止させる際に、
    (ｉ)前記停止に先行して、前記ＣＯ除去器への水素含有ガスの供給量に対する酸化ガスの供給量が、発電運転時よりも多くなるよう前記酸化ガス供給器の操作量を制御する第１の制御、及び
    (ii)前記停止後、前記改質器より前記水素含有ガスが送出される期間において、前記ＣＯ除去器への水素含有ガスの供給量に対する酸化ガスの供給量が、発電運転時よりも多くなるよう前記酸化ガス供給器の操作量を制御する第２の制御、の少なくともいずれか一方を実行し、
    　前記第１の制御及び第２の制御の少なくともいずれか一方を実行後に、前記水素生成装置内のパージ動作を実行することを特徴とする、燃料電池システム。     A reformer having a reforming catalyst that generates a hydrogen-containing gas using a raw material, a CO remover having an oxidation catalyst for reducing carbon monoxide contained in the hydrogen-containing gas by an oxidation reaction, and the CO removal A hydrogen generator comprising a first oxidizing gas supplier for supplying oxidizing gas to the vessel;
    A fuel cell that generates power using the hydrogen-containing gas supplied from the hydrogen generator;
    A fuel cell system comprising a controller,
    The controller is
    When stopping the power generation operation of the fuel cell system,
    (i) Prior to the stop, the operating amount of the oxidizing gas supplier is controlled so that the supply amount of the oxidizing gas with respect to the supply amount of the hydrogen-containing gas to the CO remover is larger than that during the power generation operation. 1 control, and
    (ii) In the period in which the hydrogen-containing gas is sent from the reformer after the stop, the supply amount of the oxidizing gas with respect to the supply amount of the hydrogen-containing gas to the CO remover is larger than that during power generation operation. Performing at least one of the second control for controlling the operation amount of the oxidizing gas supply device,
    A purge operation in the hydrogen generator is performed after performing at least one of the first control and the second control.
  2. 　前記改質器に前記改質反応に用いられる反応ガスを供給する反応ガス供給器を備え、
    　前記停止後、前記改質器より前記水素含有ガスが送出される期間は、前記停止後も前記反応ガス供給器からの前記反応ガスの供給を継続する期間を含む、請求項１記載の燃料電池システム。     A reaction gas supply device for supplying a reaction gas used for the reforming reaction to the reformer;
    2. The fuel cell according to claim 1, wherein the period in which the hydrogen-containing gas is sent from the reformer after the stop includes a period in which the supply of the reaction gas from the reaction gas supplier is continued even after the stop. system.
  3. 　前記改質器に前記改質反応に用いられる反応ガスを供給する反応ガス供給器を備え、
    　前記停止後、前記改質器より前記水素含有ガスが送出される期間は、前記反応ガス供給器を停止した後に、前記改質器内に残留した前記反応ガスから生成された前記水素含有ガスが前記ＣＯ除去器に送出される期間を含む、請求項１又は２記載の燃料電池システム。     A reaction gas supply device for supplying a reaction gas used for the reforming reaction to the reformer;
    After the stop, the hydrogen-containing gas generated from the reaction gas remaining in the reformer after the reaction gas supply device is stopped after the reaction gas supply device is stopped is the period during which the hydrogen-containing gas is sent from the reformer. The fuel cell system according to claim 1, wherein the fuel cell system includes a period sent to the CO remover.
  4. 　前記反応ガス供給器は、前記原料を供給する原料供給器、水蒸気を供給する水蒸気供給器、及び酸化ガスを供給する第２の酸化ガス供給器の少なくともいずれか一つである、請求項２または３記載の燃料電池システム。 The reaction gas supply device is at least one of a raw material supply device that supplies the raw material, a water vapor supply device that supplies water vapor, and a second oxidizing gas supply device that supplies oxidizing gas. 3. The fuel cell system according to 3.
  5. 　前記改質器を加熱するための燃焼器と、
    　前記燃焼器における燃焼を検知する燃焼検知器と、
    　前記ＣＯ除去器より送出されたガスが前記燃焼器に流入するためのガス流路と、
    　前記ガス流路を連通／遮断させる開閉弁と、を備え、
    　前記停止後、前記改質器より前記水素含有ガスが送出される期間は、前記停止後に前記開閉弁が開放している状態で、前記燃焼検知器で前記燃焼器の燃焼が検知されている期間を含む、請求項１記載の燃料電池システム。     A combustor for heating the reformer;
    A combustion detector for detecting combustion in the combustor;
    A gas flow path for the gas sent from the CO remover to flow into the combustor;
    An on-off valve for communicating / blocking the gas flow path,
    The period during which the hydrogen-containing gas is delivered from the reformer after the stop is a period during which combustion of the combustor is detected by the combustion detector in a state where the on-off valve is open after the stop. The fuel cell system according to claim 1, comprising:
  6. 　原料を用いて水素含有ガスを生成させる改質触媒を有する改質器、前記水素含有ガス中に含まれる一酸化炭素を酸化反応により低減させるための酸化触媒を有するＣＯ除去器、及び前記ＣＯ除去器に酸化ガスを供給する第１の酸化ガス供給器を備える水素生成装置と、
    　前記水素生成装置から供給される水素含有ガスを用いて発電を行う燃料電池とを備える燃料電池システムの運転方法であって、
    　前記燃料電池システムの発電運転を停止させる際に、
    (ｉ)前記停止に先行して、前記ＣＯ除去器への水素含有ガスの供給量に対する酸化ガスの供給量が、発電運転時よりも多くなるよう前記酸化ガス供給器の操作量を制御する第１の制御、及び
    (ii)前記停止後、前記改質器より前記水素含有ガスが送出される期間において、前記ＣＯ除去器への水素含有ガスの供給量に対する酸化ガスの供給量が、発電運転時よりも多くなるよう前記酸化ガス供給器の操作量を制御する第２の制御、の少なくともいずれか一方を実行し、
    　前記第１の制御及び第２の制御の少なくともいずれか一方を実行後に、前記水素生成装置内のパージ動作を実行することを特徴とする、燃料電池システムの運転方法。     A reformer having a reforming catalyst that generates a hydrogen-containing gas using a raw material, a CO remover having an oxidation catalyst for reducing carbon monoxide contained in the hydrogen-containing gas by an oxidation reaction, and the CO removal A hydrogen generator comprising a first oxidizing gas supplier for supplying oxidizing gas to the vessel;
    A fuel cell system operating method comprising a fuel cell that generates electricity using a hydrogen-containing gas supplied from the hydrogen generator,
    When stopping the power generation operation of the fuel cell system,
    (i) Prior to the stop, the operating amount of the oxidizing gas supplier is controlled so that the supply amount of the oxidizing gas with respect to the supply amount of the hydrogen-containing gas to the CO remover is larger than that during the power generation operation. 1 control, and
    (ii) In the period in which the hydrogen-containing gas is sent from the reformer after the stop, the supply amount of the oxidizing gas with respect to the supply amount of the hydrogen-containing gas to the CO remover is larger than that during power generation operation. Performing at least one of the second control for controlling the operation amount of the oxidizing gas supply device,
    A method for operating a fuel cell system, comprising: performing a purge operation in the hydrogen generator after performing at least one of the first control and the second control.
PCT/JP2010/005765 2009-09-25 2010-09-24 Fuel cell system and operation method for fuel cell system WO2011036886A1 (en)

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