WO2011122485A1 - Fuel cell system and control method for fuel cell system - Google Patents

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

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Publication number
WO2011122485A1
WO2011122485A1 PCT/JP2011/057414 JP2011057414W WO2011122485A1 WO 2011122485 A1 WO2011122485 A1 WO 2011122485A1 JP 2011057414 W JP2011057414 W JP 2011057414W WO 2011122485 A1 WO2011122485 A1 WO 2011122485A1
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reformed gas
selective oxidation
supply
fuel cell
temperature
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PCT/JP2011/057414
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French (fr)
Japanese (ja)
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加藤　恵美
晃 後藤
康嗣 橋本
貴将 長谷川
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Ｊｘ日鉱日石エネルギー株式会社
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Publication of WO2011122485A1 publication Critical patent/WO2011122485A1/en

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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
    • H01M8/04298—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
    • H01M8/0432—Temperature; Ambient temperature
    • H01M8/04373—Temperature; Ambient temperature of auxiliary devices, e.g. reformers, compressors, burners
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J8/00—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes
    • B01J8/02—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with stationary particles, e.g. in fixed beds
    • B01J8/04—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with stationary particles, e.g. in fixed beds the fluid passing successively through two or more beds
    • B01J8/0446—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with stationary particles, e.g. in fixed beds the fluid passing successively through two or more beds the flow within the beds being predominantly vertical
    • B01J8/0461—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with stationary particles, e.g. in fixed beds the fluid passing successively through two or more beds the flow within the beds being predominantly vertical in two or more cylindrical annular shaped beds
    • B01J8/0465—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with stationary particles, e.g. in fixed beds the fluid passing successively through two or more beds the flow within the beds being predominantly vertical in two or more cylindrical annular shaped beds the beds being concentric
    • B—PERFORMING OPERATIONS; TRANSPORTING
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    • 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
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    • C01B3/00—Hydrogen; Gaseous mixtures containing hydrogen; Separation of hydrogen from mixtures containing it; Purification of hydrogen
    • C01B3/50—Separation of hydrogen or hydrogen containing gases from gaseous mixtures, e.g. purification
    • C01B3/56—Separation of hydrogen or hydrogen containing gases from gaseous mixtures, e.g. purification by contacting with solids; Regeneration of used solids
    • C01B3/58—Separation of hydrogen or hydrogen containing gases from gaseous mixtures, e.g. purification by contacting with solids; Regeneration of used solids including a catalytic reaction
    • C01B3/583—Separation of hydrogen or hydrogen containing gases from gaseous mixtures, e.g. purification by contacting with solids; Regeneration of used solids including a catalytic reaction the reaction being the selective oxidation of carbon monoxide
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    • 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
    • H01M8/04701—Temperature
    • H01M8/04738—Temperature of 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
    • H01M8/04—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
    • H01M8/04753—Pressure; Flow of fuel cell reactants
    • 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
    • H01M8/04791—Concentration; Density
    • H01M8/04798—Concentration; Density of fuel cell reactants
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
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    • B01J2208/00—Processes carried out in the presence of solid particles; Reactors therefor
    • B01J2208/00008—Controlling the process
    • B01J2208/00017—Controlling the temperature
    • B01J2208/00026—Controlling or regulating the heat exchange system
    • B01J2208/00035—Controlling or regulating the heat exchange system involving measured parameters
    • B01J2208/00044—Temperature measurement
    • B01J2208/00061—Temperature measurement of the reactants
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
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    • B01J2208/00—Processes carried out in the presence of solid particles; Reactors therefor
    • B01J2208/00008—Controlling the process
    • B01J2208/00017—Controlling the temperature
    • B01J2208/00106—Controlling the temperature by indirect heat exchange
    • B01J2208/00309—Controlling the temperature by indirect heat exchange with two or more reactions in heat exchange with each other, such as an endothermic reaction in heat exchange with an exothermic reaction
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
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    • B01J2208/00—Processes carried out in the presence of solid particles; Reactors therefor
    • B01J2208/00008—Controlling the process
    • B01J2208/00017—Controlling the temperature
    • B01J2208/00504—Controlling the temperature by means of a burner
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
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    • B01J2208/00—Processes carried out in the presence of solid particles; Reactors therefor
    • B01J2208/00008—Controlling the process
    • B01J2208/00017—Controlling the temperature
    • B01J2208/0053—Controlling multiple zones along the direction of flow, e.g. pre-heating and after-cooling
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J2208/00—Processes carried out in the presence of solid particles; Reactors therefor
    • B01J2208/00008—Controlling the process
    • B01J2208/00628—Controlling the composition of the reactive mixture
    • B01J2208/00646—Means for starting up the reaction
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J2219/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
    • B01J2219/00049—Controlling or regulating processes
    • B01J2219/00191—Control algorithm
    • B01J2219/00193—Sensing a parameter
    • B01J2219/00195—Sensing a parameter of the reaction system
    • B01J2219/00202—Sensing a parameter of the reaction system at the reactor outlet
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J2219/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
    • B01J2219/00049—Controlling or regulating processes
    • B01J2219/00191—Control algorithm
    • B01J2219/00222—Control algorithm taking actions
    • B01J2219/00227—Control algorithm taking actions modifying the operating conditions
    • B01J2219/00229—Control algorithm taking actions modifying the operating conditions of the reaction system
    • B01J2219/00231—Control algorithm taking actions modifying the operating conditions of the reaction system at the reactor inlet
    • C—CHEMISTRY; METALLURGY
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    • C01B2203/00—Integrated processes for the production of hydrogen or synthesis gas
    • C01B2203/02—Processes for making hydrogen or synthesis gas
    • C01B2203/0205—Processes for making hydrogen or synthesis gas containing a reforming step
    • C01B2203/0227—Processes for making hydrogen or synthesis gas containing a reforming step containing a catalytic reforming step
    • C01B2203/0233—Processes for making hydrogen or synthesis gas containing a reforming step containing a catalytic reforming step the reforming step being a steam reforming step
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    • C01B2203/02—Processes for making hydrogen or synthesis gas
    • C01B2203/0283—Processes for making hydrogen or synthesis gas containing a CO-shift step, i.e. a water gas shift step
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    • 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
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    • C01B2203/044—Selective oxidation of carbon monoxide
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    • 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
    • C01B2203/08—Methods of heating or cooling
    • C01B2203/0805—Methods of heating the process for making hydrogen or synthesis gas
    • C01B2203/0811—Methods of heating the process for making hydrogen or synthesis gas by combustion of fuel
    • 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
    • C01B2203/12—Feeding the process for making hydrogen or synthesis gas
    • C01B2203/1205—Composition of the feed
    • C01B2203/1211—Organic compounds or organic mixtures used in the process for making hydrogen or synthesis gas
    • C01B2203/1235—Hydrocarbons
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    • C01B2203/00—Integrated processes for the production of hydrogen or synthesis gas
    • C01B2203/12—Feeding the process for making hydrogen or synthesis gas
    • C01B2203/1258—Pre-treatment of the feed
    • C01B2203/1264—Catalytic pre-treatment of the feed
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    • C01B2203/16—Controlling the process
    • C01B2203/1614—Controlling the temperature
    • 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 including a selective oxidation unit having a selective oxidation catalyst that selectively oxidizes carbon monoxide contained in a hydrogen-containing reformed gas produced by reforming a hydrocarbon-based fuel with air for selective oxidation.
  • the present invention relates to a system and a control method of the fuel cell system.
  • the shift catalyst and the selective oxidation catalyst are heated, the heating is stopped when the selective oxidation catalyst rises to a predetermined temperature T2, and the shift catalyst and the selection catalyst are selected when the shift catalyst is heated to the predetermined temperature T1.
  • the cooling of the oxidation catalyst is started, the supply of the selective oxidation air to the selective oxidation catalyst is started when the temperature of the selective oxidation catalyst starts to decrease and the temperature of the selective oxidation catalyst is equal to or lower than the predetermined temperature T3.
  • a fuel processor for preventing overheating of the selective oxidation catalyst is disclosed.
  • the active metal for example, ruthenium Ru
  • the active metal is oxidized.
  • the oxidized active metal is reduced in the subsequent selective oxidation reaction.
  • the repeated oxidation and reduction causes the active metal to aggregate and deteriorate, resulting in a problem that the catalyst performance is lowered.
  • the present invention it is possible to avoid the start of the supply of the selective oxidation air before the reformed gas reaches the selective oxidation catalyst, and thus the fuel cell system and the fuel that can suppress the deterioration of the selective oxidation catalyst It is an object of the present invention to provide a battery system control method.
  • a reforming unit that generates a reformed gas containing hydrogen from a hydrocarbon fuel using a reforming catalyst, and a reforming that the reforming unit generates
  • a reforming unit equipped with a shift catalyst that reduces the carbon monoxide contained in the gas by a shift reaction, and a selective oxidation catalyst, and the carbon monoxide contained in the reformed gas that has passed through the modification unit are selected by supplying selective oxidation air.
  • a selective oxidation unit that reduces by oxidation an air supply unit that supplies selective oxidation air to the selective oxidation unit, a combustion unit for catalyst heating that introduces reformed gas that has passed through the selective oxidation unit, and selective oxidation
  • a fuel cell stack that introduces the reformed gas that has passed through the section, and performs a reformed gas ignition determination in the combustion section, and after the successful determination of the reformed gas ignition, selective oxidation by the air supply section Selection for club And so as to start the supply of the oxidizing air.
  • the combustion section introduces the reformed gas that has passed through the selective oxidation section as a fuel. Therefore, the successful ignition of the reformed gas in the combustion section means that the selective oxidation section upstream of the combustion section (selective oxidation section). Catalyst) indicates that the reformed gas has already reached, and as a result, after the reformed gas reaches the selective oxidation section (selective oxidation catalyst), supply of selective oxidation air to the selective oxidation section is started. It will be.
  • the supply of the selective oxidation air to the selective oxidation unit is started substantially simultaneously with the start of the supply of the selective oxidation air to the selective oxidation unit.
  • the supply of the reformed gas to the fuel cell stack may be started.
  • Successful ignition of the reformed gas in the combustion section can be determined to be a stable supply state of hydrogen as a fuel, and the supply of selective oxidation air to the selective oxidation section is started by the CO in the reformed gas.
  • the reformed gas supply to the fuel cell stack is started substantially simultaneously with the start of the supply of the selective oxidation air or after a certain time from the start of the supply, so that the CO concentration is sufficiently low.
  • the supply of the reformed gas (hydrogen) to the fuel cell stack is started in a state where the stable supply of the quality gas is possible.
  • the line for bypassing the fuel cell stack and supplying the reformed gas to the combustion section is closed, and the reformed gas is supplied to the fuel cell stack.
  • Supply can be started.
  • the fuel cell stack is bypassed, the reformed gas that has passed through the selective oxidation unit is supplied to the combustion unit for combustion, and when successful ignition is determined, the bypass line is closed and the fuel cell stack is closed. The supply of the reformed gas is started.
  • a reformed gas supply line that supplies the reformed gas that has passed through the selective oxidation unit to the fuel cell stack, and off-gas from the fuel cell stack
  • Off-gas supply line supplied to the combustion section a bypass line connecting the reformed gas supply line and the off-gas supply line, a bypass valve provided in the bypass line, and a reformed gas downstream of the bypass line connection section
  • a reformed gas supply valve provided in the supply line controls the reformed gas supply valve to be closed and the bypass valve to be opened to bypass the fuel cell stack and supply the reformed gas to the combustion section.
  • the supply of the reformed gas to the fuel cell stack can be started by controlling the quality gas supply valve to be opened and the bypass valve to be closed.
  • the reformed gas that has passed through the selective oxidation unit is supplied to the combustion unit via the bypass line and the off-gas supply line.
  • the open and bypass valves are controlled to be closed, the reformed gas that has passed through the selective oxidation unit is supplied to the fuel cell stack via the reformed gas supply line, and the off-gas discharged from the fuel cell stack is supplied to the off-gas supply line. To be supplied to the combustion section.
  • the temperature of the selective oxidation catalyst is within a temperature range in which deterioration due to oxidation or heat generation can be avoided, and after the successful ignition of the reformed gas in the combustion section is determined, the selective oxidation air is supplied to the selective oxidation section. Start feeding.
  • the predetermined temperature region may be a region where the temperature of the selective oxidation catalyst is 90 ° C to 210 ° C.
  • the fuel supplied to the combustion section is shifted from the hydrocarbon-based fuel to the reformed gas to reform the combustion section.
  • the hydrocarbon-based fuel is stopped in the combustion section so that no flame is formed and the temperature
  • the temperature rise width is obtained on the basis of the lowered temperature (minimum value), and successful ignition of the reformed gas is determined when the rise width exceeds the threshold.
  • the supply of the selective oxidation air can be started after the reformed gas reaches the selective oxidation catalyst, and the active metal forming the selective oxidation catalyst is prevented from being oxidized by the selective oxidation air. Degradation of the oxidation catalyst can be suppressed.
  • FIG. 1 is a schematic configuration diagram of a fuel cell system in an embodiment. It is sectional drawing which shows the fuel processing system (FPS) in embodiment. It is a flowchart which shows the starting process of the fuel cell system in embodiment. It is a flowchart which shows the ignition determination process of the reformed gas in embodiment. It is a time chart which shows the transfer process and ignition determination process of the burner fuel in embodiment with the temperature change of a combustion part.
  • FPS fuel processing system
  • FIG. 1 is a block diagram showing a configuration of a fuel cell system according to an embodiment.
  • the fuel cell system in this embodiment performs power generation using a hydrocarbon fuel such as kerosene as a raw fuel.
  • a fuel cell system 1 includes a desulfurizer 2, a fuel processing system (hereinafter referred to as “FPS”) 3 as a reformer, and a polymer electrolyte fuel cell (hereinafter referred to as “PEFC”) stack. 4, an inverter 5, and a housing 6 for housing them.
  • the desulfurizer 2 removes sulfur from a hydrocarbon fuel supplied from the outside.
  • the desulfurizer 2 includes a desulfurization catalyst and a heater. The heater heats the desulfurization catalyst to, for example, 150 ° C. to 300 ° C., and the desulfurization catalyst performs a desulfurization treatment of the hydrocarbon fuel.
  • the FPS 3 reforms a hydrocarbon fuel to generate a hydrogen-containing reformed gas.
  • the reformer 7 generates a steam reformed gas containing hydrogen by subjecting the hydrocarbon-based fuel and steam after the desulfurization process to a steam reforming reaction using a reforming catalyst.
  • the burner combustor 8 supplies the heat necessary for the steam reforming reaction by heating the reforming catalyst of the reformer 7 with heat generated by the combustion of the fuel.
  • the shift converter 9 performs an aqueous shift reaction of the steam reformed gas generated by the reformer 7 using a shift catalyst to generate a shift reformed gas in which the concentration of carbon monoxide CO is reduced.
  • the selective oxidizer 11 causes the selective reforming reaction of the shift reformed gas generated by the converter 9 by the selective oxidation catalyst by the supply of the selective oxidation air to further reduce the concentration of carbon monoxide CO in the PEFC stack 4.
  • a reformed gas used for power generation reaction is generated.
  • the PEFC stack 4 is formed by connecting a plurality of battery cells (single cells) in series, and generates power using the reformed gas generated by the FPS 3.
  • Each battery cell constituting the PEFC stack 4 includes an anode, a cathode, and an electrolyte that is a solid polymer disposed between the anode and the cathode, and supplies reformed gas to the anode and air to the cathode.
  • the power generation reaction is performed by supplying.
  • the inverter 5 converts the DC current output from the PEFC stack 4 into an AC current.
  • the casing 6 accommodates the above-described desulfurizer 2, FPS 3, PEFC stack 4 and inverter 5 in a modular manner.
  • the fuel cell system 1 also includes a fuel line L1 for supplying hydrocarbon fuel (gas fuel such as LPG or city gas or liquid fuel such as kerosene) to the FPS 3 from the outside of the housing 6. .
  • hydrocarbon fuel gas fuel such as LPG or city gas or liquid fuel such as kerosene
  • kerosene is used as the hydrocarbon fuel.
  • the fuel line L 1 branches into a fuel line L 11 that supplies hydrocarbon fuel to the reformer 7 and a fuel line L 12 that supplies hydrocarbon fuel to the burner combustor 8.
  • the fuel line L11 and the fuel line L12 are provided with electromagnetic valves 12 and 13 for switching the supply of hydrocarbon fuel to the reformer 7 and the burner combustor 8.
  • a water line L2 for supplying water (raw water) used for steam reforming to the reformer 7 is connected to the fuel line L11 in the vicinity of the reformer 7.
  • a water tank 15 is connected to the upstream side of the water line L2, and an electromagnetic valve 14 for controlling supply / stop of water to the reformer 7 is provided in the water line L2.
  • the water tank 15 is connected with a water line L21 for supplying water from the outside of the housing 6 to the water tank 15 and a recovery water line L22 for recovering process water generated by the reaction in the PEFC stack 4. .
  • the water tank 15 is connected with a recovered water line L23 for recovering water contained in the combustion gas (exhaust gas) discharged from the burner combustor 8.
  • the recovery of water from the combustion gas via the recovery water line L23 is performed when the reformed gas is burned in the burner combustor 8.
  • a burner air line L31 for supplying air from an air supply blower 41 provided outside the housing 6 to the burner combustor 8 is provided.
  • the PEFC stack 4 is connected to the selective oxidizer 11 of the FPS 3 via the reformed gas supply line L4.
  • the PEFC stack 4 passes the reformed gas that has passed through the selective oxidizer 11 to the reformed gas supply line L4. Through.
  • the PEFC stack 4 is connected to an offgas supply line L5 for discharging offgas containing hydrogen that has not contributed to the power generation reaction.
  • the downstream side of the offgas supply line L5 is connected to the burner combustor 8.
  • the off-gas can be supplied to the burner combustor 8 as burner fuel.
  • a bypass line L14 is provided which branches from the middle of the reformed gas supply line L4 and is connected to the middle of the off gas supply line L5. Then, an electromagnetic valve (bypass valve) 26 provided in the bypass line L14 and an electromagnetic valve (reformed gas supply valve) 27 provided in the reformed gas supply line L4 downstream from the branching portion of the bypass line L14 are controlled.
  • the reformed gas generated by the FPS 3 can be switched between a state in which the reformed gas is supplied to the burner combustor 8 and a state in which the reformed gas is supplied to the PEFC stack 4.
  • the reformed gas that has passed through the selective oxidizer 11 bypasses the PEFC stack 4 and is supplied to the burner combustor 8.
  • the electromagnetic valve 27 is opened and the electromagnetic valve 26 is closed, the reformed gas that has passed through the selective oxidizer 11 is supplied to the PEFC stack 4, and off-gas discharged from the PEFC stack 4 is supplied to the burner combustor 8 as fuel.
  • a stack air line L32 for supplying air from the air supply blower 42 provided outside the housing 6 to the PEFC stack 4 is provided, and an air supply blower 43 provided outside the housing 6 is provided.
  • the selective oxidizer 11 is connected to a selective oxidizer air line L33 for supplying air (selective oxidizer air) to the selective oxidizer 11.
  • the reformed gas derived from the selective oxidation unit 11 and the off-gas from the PEFC stack 4 may contain methane, which is a hydrocarbon gas, but even if the gas contains hydrocarbons, L14 or
  • the gas introduced by the burner combustor 8 from L5 is assumed to be a hydrogen-containing reformed gas.
  • a control device (control unit) 30 having a built-in microprocessor controls each of the electromagnetic valves 12, 13, 14, 26, 27 and the blowers 41, 42, 43, an igniter 22 described later, and the like. Control the operation of the battery system.
  • FIG. 2 is a cross-sectional view of the FPS 3.
  • the burner combustor (combustion unit) 8 is a burner unit that burns burner fuel (hydrocarbon fuel, reformed gas, offgas) with air. 19 and a combustion cylinder 21 for holding the burner flame.
  • the burner unit 19 is connected to a fuel line L12, a burner air line L31, a line where an off-gas supply line L5 and a bypass line L14 merge, and an igniter which is an ignition device capable of performing an ignition operation continuously.
  • the burner fuel is ignited and burned by spark ignition of the igniter 22.
  • a carburetor (not shown) is disposed inside the fuel line L12 or the burner combustor 8, and liquid hydrocarbon fuel such as kerosene is vaporized by the vaporizer. Then, the fuel is supplied to the combustion cylinder 21.
  • the combustion cylinder 21 defines a burner combustion space S, and the flame is held in the combustion cylinder 21.
  • the combustion cylinder 21 is provided with a combustion temperature sensor 23 for detecting the temperature TB (temperature of the combustion part) in the combustion cylinder 21.
  • a cylindrical reformer casing 24 is disposed so as to surround the outside of the combustion cylinder 21, and an annular shape is provided between the outer peripheral surface of the combustion cylinder 21 and the inner peripheral surface of the reformer casing 24.
  • a catalyst housing space SC is formed.
  • an annular reforming catalyst container 25 having gaps SR1, SR2 is inserted into the inner peripheral surface of the reformer casing 24 and the outer peripheral surface of the combustion cylinder 21, respectively.
  • a gap SRE is provided between the end surface of the reforming catalyst container 25 on the burner combustor 8 side and the end surface of the reformer casing 24 on the burner combustor 8 side.
  • the reforming catalyst container 25 is filled with, for example, a reforming catalyst 25a mainly composed of nickel or ruthenium, and a raw material gas composed of a hydrocarbon-based fuel and steam after the desulfurization treatment is steamed by the reforming catalyst 25a.
  • a reforming reaction is performed to generate a steam reformed gas containing hydrogen.
  • the reforming catalyst container 25 introduces the raw material gas from the lower end, and the steam reformed gas generated by the steam reforming reaction with the reforming catalyst 25 a is generated from the outer periphery of the reforming catalyst container 25 at the upper end side. 25, is led out to the annular space SC1 surrounding 25, flows outwardly from the reforming catalyst container 25, and is introduced into a transformer (transformer) 9 disposed below the reforming catalyst container 25.
  • the combustion gas generated in the combustion cylinder 21 passes through the annular space SR ⁇ b> 1 sandwiched between the outer peripheral surface of the combustion cylinder 21 and the inner peripheral surface of the reforming catalyst container 25 toward the end on the burner combustor 8 side.
  • the annular space SR2 sandwiched between the inner peripheral surface of the reformer casing 24 and the outer peripheral surface of the reforming catalyst container 25 so as to go around the end surface of the reforming catalyst container 25 on the burner combustor 8 side.
  • the annular space SR2 is discharged to the outside through the annular space SRE1 surrounding the transformer 9.
  • a steam generator 16 for evaporating the water supplied from the water tank 15 is provided so as to surround the outside of the annular space SRE1, and the steam generated by the steam generator 16 is introduced into the reforming catalyst 25a. It is mixed with the hydrocarbon fuel after desulfurization treatment.
  • the reformed gas that has passed through the transformer (transformer section) 9 is added with selective oxidation air in the middle, and then introduced into the selective oxidizer 11 provided so as to surround the outside of the steam generator 16. Then, after the carbon monoxide concentration is reduced, it is supplied to the subsequent stage (the fuel cell stack 4 or the burner combustor 8).
  • the water supplied from the water tank 15 is supplied to the steam generator 16 after heat exchange with the reformed gas immediately after being derived from the selective oxidizer 11.
  • the high-temperature combustion gas generated in the combustion cylinder 21 flows along the inner peripheral surface and the outer peripheral surface of the reforming catalyst container 25, so that the reforming in the reforming catalyst container 25 is performed.
  • the catalyst 25a and the raw material gas are heated to a temperature (for example, 400 ° C. to 800 ° C.) necessary for the endothermic reaction in the reforming catalyst 25a.
  • the heat of the combustion gas generated in the combustion cylinder 21 (combustion section) is used for heating the shift catalyst of the shift converter 9 and the selective oxidation catalyst of the selective oxidizer 11 and further used as a heat source in the steam generator 16.
  • the burner combustor 8 is a combustion section that performs catalyst heating with combustion gas.
  • the control device 30 outputs an ON / OFF signal of the start switch 31, a combustion temperature signal TB output from the combustion temperature sensor 23, and a selection output from a catalyst temperature sensor 32 that detects the temperature TC of the selective oxidation catalyst of the selective oxidizer 11. While inputting the catalyst temperature signal TC, the operation signals are output to the electromagnetic valves 12, 13, 14, 26, 27 and the blowers 41, 42, 43, and further to the igniter 22, thereby fuel for the burner combustor 8. And the supply of air, the supply of hydrocarbon fuel and raw water to the reformer 7, the ignition operation by the igniter 22, the supply of reformed gas to the PEFC stack 4, and the like are controlled.
  • FIG. 3 is a flowchart showing a control processing procedure executed by the control device 30 when the fuel cell system 1 is started.
  • the control device 30 starts the process shown in the flowchart of FIG. 3 when an ON operation signal of the start switch 31 is input.
  • the solenoid valve 13 and the air supply blower 41 are controlled to supply hydrocarbon fuel and air to the burner combustor 8 (S111), and the igniter 22 performs ignition combustion.
  • the combustion exhaust gas of the burner combustor 8 heats the reforming catalyst 25a.
  • the reformed gas that can be supplied as fuel to the burner combustor 8 is not generated until the reformed gas is generated by the FPS 3, so carbonization such as kerosene that is the raw fuel of the reforming process is used as the burner fuel at the start-up.
  • carbonization such as kerosene that is the raw fuel of the reforming process is used as the burner fuel at the start-up.
  • heat of reforming is generated. If the hydrocarbon-based fuel is combusted in the burner combustor 8 when the fuel cell system 1 is started, the temperature TB of the burner combustor 8 rises rapidly from the normal temperature, and the hydrocarbon-based fuel as the fuel is stabilized. Therefore, the ignition success of the hydrocarbon fuel can be determined with high accuracy based on the fact that the rising speed of the combustion temperature TB exceeds the determination speed or the combustion temperature TB exceeds the ignition determination temperature. .
  • the spark ignition by the igniter 22 is stopped.
  • the temperature of the reforming catalyst 25a rises to a temperature necessary for the endothermic reaction due to the combustion of the hydrocarbon fuel in the burner combustor 8
  • the steam generator 16 rises to a temperature at which steam can be generated
  • the reformed gas is generated in the FPS3.
  • the solenoid valves 12 and 14 are controlled to supply the hydrocarbon fuel and the raw water to the reformer 7 (S112).
  • the supply of hydrocarbon fuel and raw material water to the reformer 7 is started, the supply of selective oxidation air to the selective oxidizer 11 is not started, and the reformed gas in the burner combustor 8 will be described later.
  • the supply of the selective oxidation air is started. Accordingly, the selective oxidation of carbon monoxide in the selective oxidizer 11 is not performed until it is determined that ignition of the reformed gas in the burner combustor 8 is successful, and the reformed gas having a higher carbon monoxide concentration than when selective oxidation is performed. Is derived from the selective oxidizer 11.
  • the electromagnetic valve 13 is controlled, The supply of hydrocarbon fuel to the burner combustor 8 is stopped (S113). Subsequently, the electromagnetic valve 27 is closed and the electromagnetic valve 26 is opened, and the reformed gas that has passed through the selective oxidizer 11 is supplied directly to the burner combustor 8 via the bypass line L14 (S114). In addition, the air supply blower 41 is controlled to control the air supply amount to be optimal for the combustion of the reformed gas, and the reformed gas is ignited by continuous spark ignition by the igniter 22.
  • the igniter 22 it is preferable to start the ignition operation by the igniter 22 prior to the start of supply of the reformed gas to the burner combustor 8.
  • the electromagnetic valves 26 and 27 are controlled to start supplying reformed gas to the burner combustor 8, and then the electromagnetic valve 13 is controlled to stop supplying hydrocarbon fuel to the burner combustor 8.
  • the state of supplying only the hydrocarbon-based fuel to the burner combustor 8 and the state of supplying the hydrocarbon-based fuel and the reformed gas to the burner combustor 8 are transited, and the reformed gas is supplied. Only the state is supplied to the burner combustor 8.
  • the electromagnetic valve 27 is kept closed, so that the reformed gas that has passed through the selective oxidizer 11 is Instead of being supplied to the PEFC stack 4, it is supplied to the burner combustor 8.
  • supply of the reformed gas to the burner combustor 8 it is determined whether or not the reformer gas has been successfully ignited in the burner combustor 8 (S115).
  • the details of the ignition determination are shown in the flowchart of FIG.
  • the routine shown in the flowchart of FIG. 4 is executed at each combustion temperature sampling period (every fixed time), and first, it is determined whether or not it is time to start detection of combustion temperature change (step S201).
  • the detection start timing of the combustion temperature change is, for example, when the transition condition from the hydrocarbon-based fuel to the reformed gas is satisfied, when the ignition operation by the igniter 22 is started prior to the burner fuel switching process, For a predetermined time from a point in time before the changeover of the gas, a point at which the hydrocarbon fuel supply is cut off, a point at which the reformed gas supply is started, a point at which the hydrocarbon fuel supply is cut off, or the point at which the reformed gas supply is started. It can be set later.
  • the temperature (combustion part temperature) TB detected by the temperature sensor 23 at that time is read (step S202).
  • the temperature TB read at the detection start timing of the combustion temperature change is set to the minimum temperature Tmin as an initial value (step S203).
  • the maximum judgment time for example, about 4 to 10 minutes
  • the time after the transition from the hydrocarbon-based fuel to the reformed gas is set. It is determined whether or not the determination end timing has been reached (step S204).
  • the time when the maximum determination time has elapsed from the detection start timing is set as the ignition determination end timing, and if the elapsed time from the detection start timing has not reached the maximum determination time, the reformed gas is supplied.
  • the temperature (combustion part temperature) TB in the combustion cylinder 21 detected by the temperature sensor 23 is read (step S205).
  • the lowest temperature Tmin until the previous time is compared with the temperature TB of the combustion part detected at the current sampling timing (step S206), and if the temperature TB of the combustion part detected this time is lower than the lowest temperature Tmin until the previous time.
  • the temperature TB of the combustion section detected this time is set to the minimum temperature Tmin (step S207).
  • the minimum temperature Tmin is updated to the latest detected temperature every sampling cycle.
  • the minimum temperature Tmin is not updated, and the temperature obtained by subtracting the minimum temperature Tmin until the previous time from the temperature TB of the combustion section detected this time. It is determined whether or not (the increase range of the latest temperature from the minimum temperature Tmin) is equal to or greater than a threshold value ⁇ T (for example, about 5 ° C. to 10 ° C.) (step S208). In other words, it is determined whether or not the temperature TB of the combustion portion detected by the temperature sensor 23 at the current ignition determination timing (sampling timing) is higher than the threshold ⁇ T by a minimum temperature (minimum value) Tmin.
  • a threshold value ⁇ T for example, about 5 ° C. to 10 ° C.
  • the process returns to the process of determining whether or not the maximum determination time has been reached (step S204).
  • the minimum temperature Tmin until the previous time is compared with the temperature TB of the combustion portion detected this time at every minute time interval (constant period) ignition determination timing, and the minimum temperature Tmin Update processing is performed. If Tmin ⁇ T, the comparison between the lowest temperature Tmin and the temperature TB of the combustion section detected this time is repeated.
  • the minimum temperature Tmin indicates the minimum value of the temperature TB of the combustion section between the temperature change detection start timing and the current ignition determination timing (sampling timing).
  • the temperature TB of the combustion part detected by the temperature sensor 23 at the current ignition determination timing is the lowest between the detection start timing (when switching from the hydrocarbon-based fuel to the reformed gas) and this time (current time). If it is determined that the temperature (minimum value) Tmin is higher than the threshold value ⁇ T, it is determined whether the reformed gas has been successfully ignited. When it is determined that the ignition has succeeded, the ignition operation of the igniter 22 is stopped later.
  • the minimum temperature Tmin and the detected temperature TB for each fixed period until the elapsed time from the start of the ignition determination reaches the maximum determination time (until the end timing of the ignition determination). If the success of ignition of the reformed gas is not determined even after repeated comparisons, the minimum temperature Tmin until the maximum determination time is reached and the lower limit combustion temperature Th in the reformed gas supply state are compared. (Step S210).
  • the lower limit combustion temperature Th is the lower limit value of the combustion part temperature TB when the reformed gas is combusted. If the reformed gas is continuously combusted, the temperature at which the temperature TB of the combustion part does not fall below It is.
  • the maximum determination time is reached, that is, when the minimum temperature Tmin at the determination end timing is equal to or higher than the lower limit combustion temperature Th, the maximum determination time elapses after the fuel is switched from the hydrocarbon-based fuel to the reformed gas.
  • the temperature TB of the combustion part has never fallen below the lower limit combustion temperature Th and has maintained a temperature equal to or higher than the lower limit combustion temperature Th.
  • the lower limit combustion temperature Th is a temperature at which the temperature TB of the combustion section does not fall below the reformed gas if the reformed gas continues to burn. If it has been maintained, it can be estimated that the reformed gas has been successfully ignited and the stable reformed gas combustion state is maintained, so that the reformed gas has been successfully ignited (step S209).
  • the combustion section temperature TB may have become lower than the lower limit combustion temperature Th until the maximum determination time elapses. In other words, even if it is temporary, it indicates that a misfire has occurred. Therefore, it cannot be determined that the ignition has succeeded, and the temperature rise from the minimum temperature (minimum value) Tmin to the threshold ⁇ T or more is determined to be the maximum. Since it did not occur within the time, an ignition failure (timeout: time-out of the ignition process) that did not reach the ignition state within the predetermined time is determined (step S211). If ignition failure (timeout) is determined, an alarm (warning) is issued, the supply of air, hydrocarbon fuel, and raw water to the desulfurizer 2 and FPS 3 is stopped, and the fuel cell system is reset.
  • the time chart of FIG. 5 shows an example of a temperature change when the burner fuel supplied to the burner combustor 8 is transferred from the hydrocarbon-based fuel to the reformed gas.
  • the step of using the burner fuel as a hydrocarbon-based fuel (kerosene) is shown as step 1
  • the subsequent step of using the burner fuel as a reformed gas is shown as step 2.
  • the burner fuel is switched from the hydrocarbon-based fuel to the reformed gas at time t2, but the ignition operation by the igniter 22 is started from time t1 before the transition time (switching time) t2.
  • the ignition performance of the reformed gas can be ensured.
  • time t2 when the supply of the hydrocarbon fuel is stopped and the supply of the reformed gas is started substantially simultaneously, and the burner fuel is switched from the hydrocarbon fuel to the reformed gas, immediately after that, the hydrocarbon fuel is changed.
  • the temperature TB of the combustion part temporarily rises above the temperature (for example, about 750 ° C.) at the time of combustion of the hydrocarbon-based fuel before switching.
  • the period from time t2 to time t3 is a temperature increase period due to mixed firing.
  • the supply of the reformed gas to the burner combustor 8 is not stable, and the burner combustor 8 is misfired due to a temporary stagnation of the supply of the reformed gas. Temperature TB may drop.
  • the period from time t3 to time t4 is a temperature drop period of the combustion section due to a temporary stagnation of the reformed gas supply.
  • start the supply of reformed gas wait until the reformed gas combustion stabilizes, and stop the supply of hydrocarbon fuel to suppress transient misfires. Then, the burner fuel can be switched. In this case, however, an excessive temperature increase may be caused by the prolonged mixed firing time.
  • the reformed gas supply shifts to combustion with the reformed gas alone in an unstable state.
  • a temperature drop as shown between time t3 and time t4 may occur. While the ignition operation by the igniter 22 is continued during the temperature drop due to the misfire as described above, the supply stability of the reformed gas is improved with time, so that the ignition is successful and the reformed gas is directly maintained.
  • the temperature started to rise due to ignition at the time t4 it immediately misfired. The case where the temperature starts to fall again from time t5 is shown.
  • the temperature TB of the combustion section gradually increases from the time t6, and finally, the reformed gas is improved. It converges around a stable temperature (for example, about 730 ° C.) in the combustion state of the gas.
  • the ignition determination according to the present embodiment is configured to determine the success of ignition when the increase width with respect to the minimum temperature Tmin is equal to or greater than the threshold value ⁇ T. For example, in the example illustrated in FIG. 5, the minimum temperature Tmin is until time t3.
  • the temperature of the combustion section (for example, about 750 ° C.) is maintained, and when the temperature rises in the mixed combustion state accompanying the switching of the burner fuel, the temperature TB of the combustion section is the lowest The temperature exceeds the temperature Tmin.
  • the threshold value ⁇ T a value that exceeds the temperature rise due to the co-firing state is set in advance, and the successful ignition is not determined for the temperature rise due to co-firing.
  • the burner fuel is switched so that the temperature rise due to mixed combustion does not exceed the threshold value ⁇ T.
  • the minimum temperature Tmin is updated to a lower temperature accordingly, and a temperature increase due to temporary ignition occurs.
  • the detected temperature TB at time t4 is set to the minimum temperature Tmin.
  • the temperature becomes higher than the minimum temperature Tmin that is the detected temperature TB at time t4, but the ignition success is not determined for such temporary temperature increase.
  • a threshold value ⁇ T is set in advance, and the ignition success is determined based on a relative comparison with the minimum temperature Tmin that is the detected temperature at the time t4 even at the temperature TB at the time t5 when the temperature reaches a peak value due to temporary ignition. There is no.
  • the minimum temperature Tmin is updated to a lower temperature accordingly.
  • the detected temperature TB at that time is changed to the minimum temperature Tmin. Set to.
  • the threshold ⁇ T is higher than the temperature TB at time t6.
  • the ignition success is determined at the time (time t7) when the temperature becomes higher than the above.
  • the threshold value ⁇ T does not determine whether ignition has succeeded due to a temperature rise due to mixed combustion or temporary ignition, and succeeds in ignition only after the transition from the misfire state to the stable combustion state and the temperature rises smoothly. Pre-adapted to determine.
  • the ignition operation by the igniter 22 is stopped at a time t8 when a preset delay time has elapsed from the time t7 when it was determined that ignition was successful.
  • the temperature rise rate temperature rise speed immediately after time t2, time t4, and time t6 was comparable, for example.
  • the deviation between the highest temperature finally reached and the temperature TB at time t2 and time t4 is less than the threshold value ⁇ T, and successful ignition is not determined.
  • the temperature rise from time t6 starting from the temperature TB at time t6, the temperature rises smoothly on the basis of the fact that ignition was actually successful, so that the temperature ⁇ B exceeds the threshold value ⁇ T above the temperature TB at time t6.
  • the ignition success is determined. In other words, if the temperature rises smoothly based on the fact that ignition has actually succeeded, even if the temperature rise gradient is more gradual than when the temperature rises due to mixed firing or temporary ignition, Successful ignition can be determined.
  • the ignition determination means / method is not limited to the above-described configuration for determining by the range from the minimum temperature, and various known ignition determination means / methods can be applied.
  • the combustion detected by the temperature sensor 23 Successful ignition can be determined when the time differential value (temperature rise rate) of the part temperature TB exceeds a threshold value, and temperature detection is performed at a plurality of locations by a plurality of temperature sensors 23 to determine successful ignition.
  • the ignition determination is repeated until the reformed gas ignition success or timeout (ignition failure) is determined.
  • the temperature TC of the selective oxidation catalyst of the selective oxidizer 11 detected by the catalyst temperature sensor 32 is selected. It is determined whether or not the temperature is within a temperature range (allowable temperature range) in which the supply start of the oxidizing air is allowed (S116).
  • the minimum temperature in the allowable temperature range is the minimum temperature at which oxygen does not remain in the atmosphere of the selective oxidation catalyst and oxidize the selective oxidation catalyst when the supply of selective oxidation air is started.
  • the maximum temperature in the temperature range is the maximum temperature at which catalyst deterioration due to the occurrence of methanation runaway upon the start of the supply of selective oxidation air can be suppressed, and the allowable temperature range is, for example, about 90 ° C. to 210 ° C.
  • the temperature TC of the selective oxidation catalyst is outside the allowable temperature range (90 ° C. or less, or 210 ° C. or more)
  • the selection is performed. Oxidation of the oxidation catalyst and methanation runaway will occur. Therefore, the temperature determination is repeated until the temperature TC of the selective oxidation catalyst falls within the temperature range in which the supply of selective oxidation air is allowed to be started, until the temperature rises or falls to a temperature that allows the supply of selective oxidation air to be permitted. stand by.
  • the selective oxidation catalyst When the temperature TC of the selective oxidation catalyst is higher than the maximum temperature in the allowable temperature range, the selective oxidation catalyst is cooled by circulating water in the cooling pipe provided in the selective oxidation catalyst, and the temperature TC of the selective oxidation catalyst. To lower. In addition, when the temperature TC of the selective oxidation catalyst is lower than the lowest temperature in the allowable temperature range, the temperature can be increased by heating with a heater provided in the vicinity of the selective oxidation catalyst. The combustion exhaust gas may be guided around the selective oxidation catalyst to heat the selective oxidation catalyst.
  • the supply of selective oxidation air to the selective oxidizer 11 that has been stopped is started, and the selective oxidation of the carbon monoxide CO in the selective oxidizer 11 is started.
  • Start (S117).
  • the supply of selective oxidation air to the selective oxidizer 11 is started and the CO concentration in the reformed gas is reduced by selective oxidation, the reformed gas derived from the selective oxidizer 11 is supplied to the anode of the PEFC stack 4. Is started, and the air supply blower 42 is controlled to start supplying air to the cathode of the PEFC stack 4 (S118).
  • the electromagnetic valve 26 Prior to the start of the supply of selective oxidation air (before the determination of successful reformed gas ignition), the electromagnetic valve 26 is opened and the electromagnetic valve 27 is closed so that the reformed gas that has passed through the selective oxidizer 11 is directly burned. After supplying to the combustor 8 and starting the supply of the selective oxidation air (after the determination of the successful ignition of the reformed gas), the electromagnetic valve 26 is closed and the electromagnetic valve 27 is opened, so that the reforming that has passed through the selective oxidizer 11 is performed.
  • the quality gas is supplied to the anode of the PEFC stack 4, and the off gas that has passed through the anode is supplied to the burner combustor 8.
  • the start of supply of power generation air to the PEFC stack 4 may be delayed from the start of supply of the reformed gas to the PEFC stack 4. Thereafter, after the temperature of the PEFC stack 4 is raised to a predetermined temperature, power is taken out from the PEFC stack 4 by taking out a current from the PEFC stack 4.
  • the supply of selective oxidation air to the selective oxidizer 11 is started.
  • the reformed gas that has passed through the selective oxidizer 11 is supplied to the burner combustor 8, the fact that the reformer gas has been successfully ignited in the burner combustor 8 has reached the selective oxidizer 11.
  • the selective oxidizer 11 shows that it is supplied stably. Therefore, if the supply of the selective oxidation air to the selective oxidizer 11 is started after determining the successful ignition of the reformed gas in the burner combustor 8, the reformed gas is selected before reaching the selective oxidizer 11. It is possible to avoid starting the supply of the oxidizing air.
  • the supply of selective oxidation air is started before the reformed gas reaches the selective oxidizer 11, even if the temperature TC of the selective oxidation catalyst is within a temperature range in which the supply of selective oxidation air can be permitted to start. Even so, the active metal of the selective oxidation catalyst is oxidized by the oxygen contained in the selective oxidation air. Thereafter, the selective oxidation reaction starts when the reformed gas reaches the selective oxidizer 11 and the active metal is reduced. However, the active metal deteriorates by repeated oxidation and reduction.
  • the activity of the selective oxidation catalyst is increased by the supply of the selective oxidation air. Without oxidizing the metal, the deterioration of the active metal due to repeated oxidation and reduction can be prevented, and the catalytic action of the selective oxidation catalyst can be exhibited stably.
  • the supply of the selective oxidation air is started on the condition that the temperature of the selective oxidation catalyst is within the allowable temperature range. Therefore, the oxidation of the active metal due to the supply of the selective oxidation air under the low temperature condition and the overheating of the active metal due to the supply of the selective oxidation air under the high temperature condition can be prevented.
  • kerosene is exemplified as the hydrocarbon fuel used in the burner combustor 8 (combustion unit), but in addition, biofuel using gasoline, naphtha, light oil, methanol, ethanol, dimethyl ether, and biomass is used.
  • the hydrocarbon fuel is not limited to the liquid fuel, and may be a gaseous fuel such as city gas.
  • the temperature TB of the combustion part is not limited to the temperature transition tendency shown in FIG. 5 because it varies depending not only on the fuel supplied to the combustion part but also on the attachment position (sensing position) of the temperature sensor 23.
  • the fuel cell system provided with the solid oxide fuel cell (SOFC) stack may be sufficient.
  • the reformer 7 and the transformer 9 are integrally formed, the reformer 7, the transformer 9 and the selective oxidation unit 11 are integrally formed, or the desulfurizer 2 and the reformer. 7 and the transformer 9 can be integrally formed.
  • the burner combustor 8 is used for heating a shift catalyst (for example, a mixed oxide of Fe—Cr) provided in the converter 9, and the reformed gas that has passed through the selective oxidizer 11 is used as fuel for the burner combustor 8.
  • the structure which supplies may be sufficient.
  • SYMBOLS 1 Fuel cell system 1, 3 ... Fuel processing system (FPS), 4 ... Polymer electrolyte fuel cell (PEFC) stack, 7 ... Reformer (reforming part), 8 ... Burner combustor (combustion part), DESCRIPTION OF SYMBOLS 9 ... Transformer (denaturing part), 11 ... Selective oxidizer (selective oxidation part), 21 ... Combustion cylinder, 22 ... Igniter (ignition device), 23 ... Combustion temperature sensor, 30 ... Control device (control part), 32 ... Catalyst temperature sensor

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Abstract

Disclosed is a fuel cell system and a control system that can avoid commencement of the supply of air for selective oxidation before reformed gas reaches a selective oxidation catalyst. The fuel cell system and control method commences supply of hydrocarbon fuel and air to a burner combustor, heats a reformer by burner combustion, supplies hydrocarbon fuel and raw-material water to the reformer in which the temperature has increased, and generates reformed gas. Once the reformed gas is generated, the fuel cell system and control method swaps the burner combustor fuel from hydrocarbon fuel to reformed gas and evaluates the success of the reformed gas ignition based on the combustion temperature. If the fuel cell system and control method judges that ignition was successful, said system and control method then determines whether or not the selective oxidation catalyst temperature is within the temperature range that supply of air for selective oxidation can be commenced. If the temperature of the selective oxidation catalyst is within the aforementioned temperature range, the fuel cell system and control method commence supply of air for selective oxidation to the selective oxidation catalyst and supplies reformed gas with a reduced carbon monoxide concentration as a result of selective oxidation to a stack.

Description

燃料電池システム及び燃料電池システムの制御方法FUEL CELL SYSTEM AND CONTROL METHOD FOR FUEL CELL SYSTEM
　本発明は、炭化水素系燃料を改質して生成した水素含有改質ガスが含む一酸化炭素を、選択酸化用空気によって選択的に酸化する選択酸化触媒を有する選択酸化部を備えた燃料電池システム、及び、係る燃料電池システムの制御方法に関する。 The present invention relates to a fuel cell including a selective oxidation unit having a selective oxidation catalyst that selectively oxidizes carbon monoxide contained in a hydrogen-containing reformed gas produced by reforming a hydrocarbon-based fuel with air for selective oxidation. The present invention relates to a system and a control method of the fuel cell system.
　特許文献１には、シフト触媒及び選択酸化触媒を加熱し、選択酸化触媒が所定温度Ｔ２にまで上昇したときに加熱を停止し、シフト触媒が所定温度Ｔ１に昇温した時点でシフト触媒及び選択酸化触媒の冷却を開始させ、選択酸化触媒の温度が減少に転じ、かつ、選択酸化触媒の温度が所定温度Ｔ３以下であるときに、選択酸化触媒への選択酸化用空気の供給を開始させることで、選択酸化触媒の過熱を防止する燃料プロセッサが開示されている。 In Patent Document 1, the shift catalyst and the selective oxidation catalyst are heated, the heating is stopped when the selective oxidation catalyst rises to a predetermined temperature T2, and the shift catalyst and the selection catalyst are selected when the shift catalyst is heated to the predetermined temperature T1. The cooling of the oxidation catalyst is started, the supply of the selective oxidation air to the selective oxidation catalyst is started when the temperature of the selective oxidation catalyst starts to decrease and the temperature of the selective oxidation catalyst is equal to or lower than the predetermined temperature T3. A fuel processor for preventing overheating of the selective oxidation catalyst is disclosed.
特開２００８－１４３７５１号公報JP 2008-143751 A
　ところで、選択酸化触媒の温度が、選択酸化用空気の供給を開始させことができる条件であっても、改質ガスが選択酸化触媒に到達する前に選択酸化用空気の供給を開始すると、酸素によって選択酸化触媒の活性金属（例えば、ルテニウムＲｕ）が酸化してしまう。酸化した活性金属は、その後の選択酸化反応において還元されるが、酸化・還元を繰り返すことで活性金属が凝集して劣化し、触媒性能が低下するという問題が生じる。 By the way, even if the temperature of the selective oxidation catalyst is a condition under which the supply of the selective oxidation air can be started, if the supply of the selective oxidation air is started before the reformed gas reaches the selective oxidation catalyst, As a result, the active metal (for example, ruthenium Ru) of the selective oxidation catalyst is oxidized. The oxidized active metal is reduced in the subsequent selective oxidation reaction. However, the repeated oxidation and reduction causes the active metal to aggregate and deteriorate, resulting in a problem that the catalyst performance is lowered.
　そこで本発明では、改質ガスが選択酸化触媒に到達する前に選択酸化用空気の供給を開始してしまうことを回避でき、以って、選択酸化触媒の劣化を抑制できる燃料電池システム及び燃料電池システムの制御方法を提供することを目的とする。 Therefore, in the present invention, it is possible to avoid the start of the supply of the selective oxidation air before the reformed gas reaches the selective oxidation catalyst, and thus the fuel cell system and the fuel that can suppress the deterioration of the selective oxidation catalyst It is an object of the present invention to provide a battery system control method.
　そのため、請求項１，８の燃料電池システム及び制御方法では、改質触媒を用いて炭化水素系燃料から水素を含有する改質ガスを生成する改質部と、改質部が生成した改質ガスが含む一酸化炭素をシフト反応により低減するシフト触媒を備えた変性部と、選択酸化触媒を備え、変性部を通過した改質ガスが含む一酸化炭素を、選択酸化用空気の供給によって選択酸化して低減する選択酸化部と、選択酸化部に対して選択酸化用空気を供給する空気供給部と、選択酸化部を通過した改質ガスを導入する触媒加熱用の燃焼部と、選択酸化部を通過した改質ガスを導入する燃料電池スタックと、を含む燃料電池システムにおいて、燃焼部における改質ガスの着火判定を行ない、改質ガスの着火成功の判定後に、空気供給部による選択酸化部への選択酸化用空気の供給を開始させるようにした。 Therefore, in the fuel cell system and the control method according to claims 1 and 8, a reforming unit that generates a reformed gas containing hydrogen from a hydrocarbon fuel using a reforming catalyst, and a reforming that the reforming unit generates A reforming unit equipped with a shift catalyst that reduces the carbon monoxide contained in the gas by a shift reaction, and a selective oxidation catalyst, and the carbon monoxide contained in the reformed gas that has passed through the modification unit are selected by supplying selective oxidation air. A selective oxidation unit that reduces by oxidation, an air supply unit that supplies selective oxidation air to the selective oxidation unit, a combustion unit for catalyst heating that introduces reformed gas that has passed through the selective oxidation unit, and selective oxidation A fuel cell stack that introduces the reformed gas that has passed through the section, and performs a reformed gas ignition determination in the combustion section, and after the successful determination of the reformed gas ignition, selective oxidation by the air supply section Selection for club And so as to start the supply of the oxidizing air.
　ここで、燃焼部は、選択酸化部を通過した改質ガスを燃料として導入するから、燃焼部において改質ガスの着火に成功したことは、燃焼部よりも上流側の選択酸化部（選択酸化触媒）に改質ガスが既に到達していることを示し、結果、選択酸化部（選択酸化触媒）に改質ガスが到達してから、選択酸化部への選択酸化用空気の供給を開始することになる。 Here, the combustion section introduces the reformed gas that has passed through the selective oxidation section as a fuel. Therefore, the successful ignition of the reformed gas in the combustion section means that the selective oxidation section upstream of the combustion section (selective oxidation section). Catalyst) indicates that the reformed gas has already reached, and as a result, after the reformed gas reaches the selective oxidation section (selective oxidation catalyst), supply of selective oxidation air to the selective oxidation section is started. It will be.
　上記請求項１，８の構成において、請求項２，９のように、選択酸化部への選択酸化用空気の供給開始と略同時、又は、前記選択酸化部への選択酸化用空気の供給開始から一定時間後に、燃料電池スタックへの改質ガスの供給を開始するとよい。
　燃焼部において改質ガスの着火に成功したことは、燃料としての水素の安定供給状態であると判断でき、かつ、選択酸化部への選択酸化用空気の供給開始は、改質ガス中のＣＯ濃度が低下することを示すから、選択酸化用空気の供給開始と略同時又は供給開始から一定時間後に、燃料電池スタックへの改質ガスの供給を開始させることで、ＣＯ濃度が十分に低い改質ガスの安定供給が可能な状態で、燃料電池スタックに対する改質ガス（水素）の供給を開始させることになる。 In the configuration of the first and eighth aspects, as in the second and ninth aspects, the supply of the selective oxidation air to the selective oxidation unit is started substantially simultaneously with the start of the supply of the selective oxidation air to the selective oxidation unit. After a certain period of time, the supply of the reformed gas to the fuel cell stack may be started.
Successful ignition of the reformed gas in the combustion section can be determined to be a stable supply state of hydrogen as a fuel, and the supply of selective oxidation air to the selective oxidation section is started by the CO in the reformed gas. Since the concentration decreases, the reformed gas supply to the fuel cell stack is started substantially simultaneously with the start of the supply of the selective oxidation air or after a certain time from the start of the supply, so that the CO concentration is sufficiently low. The supply of the reformed gas (hydrogen) to the fuel cell stack is started in a state where the stable supply of the quality gas is possible.
　また、請求項２，９の構成において、請求項３，１０のように、燃料電池スタックをバイパスして改質ガスを燃焼部に供給するラインを閉じて、燃料電池スタックへの改質ガスの供給を開始させることができる。
　システムの起動当初は、燃料電池スタックをバイパスして、選択酸化部を通過した改質ガスを、燃焼部に供給して燃焼させ、着火成功を判定すると、バイパスラインを閉じて、燃料電池スタックへの改質ガスの供給を開始させる。 Further, in the configurations of claims 2 and 9, as in claims 3 and 10, the line for bypassing the fuel cell stack and supplying the reformed gas to the combustion section is closed, and the reformed gas is supplied to the fuel cell stack. Supply can be started.
At the start of the system, the fuel cell stack is bypassed, the reformed gas that has passed through the selective oxidation unit is supplied to the combustion unit for combustion, and when successful ignition is determined, the bypass line is closed and the fuel cell stack is closed. The supply of the reformed gas is started.
　また、請求項３，１０の構成において、請求項４，１１のように、選択酸化部を通過した改質ガスを燃料電池スタックに供給する改質ガス供給ラインと、燃料電池スタックからのオフガスを前記燃焼部に供給するオフガス供給ラインと、改質ガス供給ラインとオフガス供給ラインとを接続するバイパスラインと、バイパスラインに設けたバイパス弁と、バイパスラインの接続部よりも下流側の改質ガス供給ラインに設けた改質ガス供給弁と、を備え、改質ガス供給弁を閉、バイパス弁を開に制御して、燃料電池スタックをバイパスして改質ガスを燃焼部に供給し、改質ガス供給弁を開、バイパス弁を閉に制御して、燃料電池スタックへの改質ガスの供給を開始することができる。 Further, in the configurations of claims 3 and 10, as in claims 4 and 11, a reformed gas supply line that supplies the reformed gas that has passed through the selective oxidation unit to the fuel cell stack, and off-gas from the fuel cell stack Off-gas supply line supplied to the combustion section, a bypass line connecting the reformed gas supply line and the off-gas supply line, a bypass valve provided in the bypass line, and a reformed gas downstream of the bypass line connection section A reformed gas supply valve provided in the supply line, and controls the reformed gas supply valve to be closed and the bypass valve to be opened to bypass the fuel cell stack and supply the reformed gas to the combustion section. The supply of the reformed gas to the fuel cell stack can be started by controlling the quality gas supply valve to be opened and the bypass valve to be closed.
　改質ガス供給弁を閉、バイパス弁を開に制御することで、選択酸化部を通過した改質ガスは、バイパスライン及びオフガス供給ラインを介して燃焼部に供給され、改質ガス供給弁を開、バイパス弁を閉に制御すると、選択酸化部を通過した改質ガスは、改質ガス供給ラインを介して燃料電池スタックに供給され、燃料電池スタックから排出されるオフガスは、オフガス供給ラインを介して燃焼部に供給される。 By controlling the reformed gas supply valve to be closed and the bypass valve to be opened, the reformed gas that has passed through the selective oxidation unit is supplied to the combustion unit via the bypass line and the off-gas supply line. When the open and bypass valves are controlled to be closed, the reformed gas that has passed through the selective oxidation unit is supplied to the fuel cell stack via the reformed gas supply line, and the off-gas discharged from the fuel cell stack is supplied to the off-gas supply line. To be supplied to the combustion section.
　上記請求項１～４，８～１１の構成において、請求項５，１２のように、燃焼部における改質ガスの着火成功を判定し、かつ、選択酸化触媒の温度が所定温度領域内である場合に、空気供給部による選択酸化部への選択酸化用空気の供給を開始するとよい。
　選択酸化触媒の温度が低い状態で選択酸化用空気を供給すると、未燃の酸素が残存し、選択酸化触媒の活性金属を酸化させてしまい、また、選択酸化触媒の温度が高い状態で選択酸化用空気を供給すると、メタネーション暴走によって激しく発熱し、触媒が劣化する。そこで、選択酸化触媒の温度が、酸化や発熱による劣化を回避できる温度域内であって、かつ、燃焼部における改質ガスの着火成功を判定してから、選択酸化部への選択酸化用空気の供給を開始させる。 In the configurations of claims 1 to 4 and 8 to 11, as in claims 5 and 12, it is determined whether the reformed gas has been successfully ignited in the combustion section, and the temperature of the selective oxidation catalyst is within a predetermined temperature range. In this case, the supply of selective oxidation air to the selective oxidation unit by the air supply unit may be started.
If air for selective oxidation is supplied with the temperature of the selective oxidation catalyst being low, unburned oxygen remains, oxidizing the active metal of the selective oxidation catalyst, and selective oxidation with the temperature of the selective oxidation catalyst being high. When supplying commercial air, the catalyst is deteriorated due to intense heat generation due to methanation runaway. Therefore, the temperature of the selective oxidation catalyst is within a temperature range in which deterioration due to oxidation or heat generation can be avoided, and after the successful ignition of the reformed gas in the combustion section is determined, the selective oxidation air is supplied to the selective oxidation section. Start feeding.
　上記請求項５，１２の構成において、請求項６，１３のように、前記所定温度領域を、選択酸化触媒の温度が９０℃～２１０℃の領域とするとよい。
　また、上記請求項１～６，８～１３の構成において、請求項７，１４のように、燃焼部に供給する燃料を、炭化水素系燃料から改質ガスに移行させ、燃焼部に対する改質ガスの供給を開始すると、この改質ガス供給開始後から周期的なサンプリングタイミングまでの間における燃焼部の温度の最低値を検出し、前記最低値からの温度上昇幅が閾値を上回った場合に、改質ガスの着火成功を判定することができる。
　燃焼部に対する改質ガスの供給を開始した直後、換言すれば、炭化水素系燃料から改質ガスに移行させた直後で、燃焼部において炭化水素系燃料が停止されるので火炎が形成されなくなり温度が低下し、その低下した温度（最低値）を基準として温度上昇幅を求め、上昇幅が閾値を越えた時点で改質ガスの着火成功を判定する。 In the configurations of the fifth and twelfth aspects, as in the sixth and thirteenth aspects, the predetermined temperature region may be a region where the temperature of the selective oxidation catalyst is 90 ° C to 210 ° C.
Further, in the configurations of the first to sixth and eighth to thirteenth aspects, as in the seventh and fourteenth aspects, the fuel supplied to the combustion section is shifted from the hydrocarbon-based fuel to the reformed gas to reform the combustion section. When the gas supply is started, when the minimum value of the temperature of the combustion section between the start of the supply of the reformed gas and the periodic sampling timing is detected, and the temperature rise from the minimum value exceeds the threshold value, The successful ignition of the reformed gas can be determined.
Immediately after the start of the supply of the reformed gas to the combustion section, in other words, immediately after the transition from the hydrocarbon-based fuel to the reformed gas, the hydrocarbon-based fuel is stopped in the combustion section so that no flame is formed and the temperature The temperature rise width is obtained on the basis of the lowered temperature (minimum value), and successful ignition of the reformed gas is determined when the rise width exceeds the threshold.
　上記発明によると、改質ガスが選択酸化触媒に到達してから選択酸化用空気の供給を開始することができ、選択酸化触媒を形成する活性金属の選択酸化用空気による酸化を防いで、選択酸化触媒の劣化を抑制することができる。 According to the above invention, the supply of the selective oxidation air can be started after the reformed gas reaches the selective oxidation catalyst, and the active metal forming the selective oxidation catalyst is prevented from being oxidized by the selective oxidation air. Degradation of the oxidation catalyst can be suppressed.
実施形態における燃料電池システムの概略構成図である。1 is a schematic configuration diagram of a fuel cell system in an embodiment. 実施形態における燃料処理システム（ＦＰＳ）を示す断面図である。It is sectional drawing which shows the fuel processing system (FPS) in embodiment. 実施形態における燃料電池システムの起動処理を示すフローチャートである。It is a flowchart which shows the starting process of the fuel cell system in embodiment. 実施形態における改質ガスの着火判定処理を示すフローチャートである。It is a flowchart which shows the ignition determination process of the reformed gas in embodiment. 実施形態におけるバーナ燃料の移行処理及び着火判定処理を、燃焼部の温度変化と共に示すタイムチャートである。It is a time chart which shows the transfer process and ignition determination process of the burner fuel in embodiment with the temperature change of a combustion part.
　以下に本発明の実施の形態を説明する。
　図１は、実施形態の燃料電池システムを示す構成ブロック図である。
　本実施形態における燃料電池システムは、原燃料として灯油などの炭化水素系燃料を用いて発電を行なうものである。 Embodiments of the present invention will be described below.
FIG. 1 is a block diagram showing a configuration of a fuel cell system according to an embodiment.
The fuel cell system in this embodiment performs power generation using a hydrocarbon fuel such as kerosene as a raw fuel.
　図１に示すように、燃料電池システム１は、脱硫器２、改質装置としての燃料処理システム（以下「ＦＰＳ」とする）３、固体高分子形燃料電池（以下「ＰＥＦＣ」とする）スタック４、インバータ５、及び、これらを収容する筐体６を備えている。
　脱硫器２は、外部から供給する炭化水素系燃料から硫黄分を除去するものである。この脱硫器２は、脱硫触媒及びヒータを備え、ヒータは脱硫触媒を例えば１５０℃～３００℃に加熱し、脱硫触媒は炭化水素系燃料の脱硫処理を行う。尚、脱硫触媒として、室温程度の温度条件で使用するものを備えてもよい。 As shown in FIG. 1, a fuel cell system 1 includes a desulfurizer 2, a fuel processing system (hereinafter referred to as “FPS”) 3 as a reformer, and a polymer electrolyte fuel cell (hereinafter referred to as “PEFC”) stack. 4, an inverter 5, and a housing 6 for housing them.
The desulfurizer 2 removes sulfur from a hydrocarbon fuel supplied from the outside. The desulfurizer 2 includes a desulfurization catalyst and a heater. The heater heats the desulfurization catalyst to, for example, 150 ° C. to 300 ° C., and the desulfurization catalyst performs a desulfurization treatment of the hydrocarbon fuel. In addition, you may provide as a desulfurization catalyst what is used on temperature conditions about room temperature.
　ＦＰＳ３は、炭化水素系燃料を改質して水素含有改質ガスを生成するものであり、改質器（改質部）７，バーナ燃焼器（燃焼部）８，変成器（変成部）９及び選択酸化器（選択酸化部）１１を有している。
　改質器７は、脱硫処理後の炭化水素系燃料と水蒸気とを改質触媒で水蒸気改質反応させて、水素を含有する水蒸気改質ガスを生成する。 The FPS 3 reforms a hydrocarbon fuel to generate a hydrogen-containing reformed gas. The reformer (reformer) 7, the burner combustor (combustor) 8, and the transformer (transformer) 9 And a selective oxidizer (selective oxidizer) 11.
The reformer 7 generates a steam reformed gas containing hydrogen by subjecting the hydrocarbon-based fuel and steam after the desulfurization process to a steam reforming reaction using a reforming catalyst.
　バーナ燃焼器８は、燃料の燃焼で発生する熱で改質器７の改質触媒を加熱することで、水蒸気改質反応に必要な熱量を供給する。
　変成器９は、改質器７が生成した水蒸気改質ガスをシフト触媒で水性シフト反応させて、一酸化炭素ＣＯの濃度を低下させたシフト改質ガスを生成する。 The burner combustor 8 supplies the heat necessary for the steam reforming reaction by heating the reforming catalyst of the reformer 7 with heat generated by the combustion of the fuel.
The shift converter 9 performs an aqueous shift reaction of the steam reformed gas generated by the reformer 7 using a shift catalyst to generate a shift reformed gas in which the concentration of carbon monoxide CO is reduced.
　また、選択酸化器１１は、変成器９が生成したシフト改質ガスを、選択酸化空気の供給によって選択酸化触媒で選択酸化反応させて一酸化炭素ＣＯの濃度を更に低下させ、ＰＥＦＣスタック４における発電反応に用いる改質ガスを生成する。
　ＰＥＦＣスタック４は、複数の電池セル（単セル）を複数直列接続してなり、ＦＰＳ３が生成した改質ガスを用いて発電する。ＰＥＦＣスタック４を構成する各電池セルは、アノードと、カソードと、アノード及びカソード間に配置した固体高分子である電解質とを有しており、アノードに改質ガスを供給させると共に、カソードに空気を供給させることで、発電反応が行われる。 In addition, the selective oxidizer 11 causes the selective reforming reaction of the shift reformed gas generated by the converter 9 by the selective oxidation catalyst by the supply of the selective oxidation air to further reduce the concentration of carbon monoxide CO in the PEFC stack 4. A reformed gas used for power generation reaction is generated.
The PEFC stack 4 is formed by connecting a plurality of battery cells (single cells) in series, and generates power using the reformed gas generated by the FPS 3. Each battery cell constituting the PEFC stack 4 includes an anode, a cathode, and an electrolyte that is a solid polymer disposed between the anode and the cathode, and supplies reformed gas to the anode and air to the cathode. The power generation reaction is performed by supplying.
　インバータ５は、ＰＥＦＣスタック４が出力するＤＣ電流をＡＣ電流に変換する。
　筐体６は、その内部に、前述の脱硫器２、ＦＰＳ３、ＰＥＦＣスタック４及びインバータ５をモジュール化して収容する。
　また、燃料電池システム１は、筐体６の外部からＦＰＳ３に炭化水素系燃料（ＬＰＧや都市ガスなどの気体燃料、又は、灯油などの液体燃料）を供給するための燃料ラインＬ１を備えている。尚、本実施形態においては、炭化水素系燃料として灯油を用いる。 The inverter 5 converts the DC current output from the PEFC stack 4 into an AC current.
The casing 6 accommodates the above-described desulfurizer 2, FPS 3, PEFC stack 4 and inverter 5 in a modular manner.
The fuel cell system 1 also includes a fuel line L1 for supplying hydrocarbon fuel (gas fuel such as LPG or city gas or liquid fuel such as kerosene) to the FPS 3 from the outside of the housing 6. . In the present embodiment, kerosene is used as the hydrocarbon fuel.
　燃料ラインＬ１は、脱硫器２の下流側において、炭化水素系燃料を改質器７に供給する燃料ラインＬ１１と、炭化水素系燃料をバーナ燃焼器８に供給する燃料ラインＬ１２とに分岐する。
　また、燃料ラインＬ１１及び燃料ラインＬ１２には、改質器７及びバーナ燃焼器８への炭化水素系燃料の供給を切り替える電磁バルブ１２，１３を設けてある。
　更に、改質器７付近の燃料ラインＬ１１には、水蒸気改質に用いる水（原料水）を改質器７に供給するための水ラインＬ２を連結してある。
　尚、燃料ラインＬ１２を、脱硫器を介さずに直接バーナ燃焼器８に接続し、脱硫処理していない炭化水素系燃料を、バーナ燃焼器８に供給することも可能である。 On the downstream side of the desulfurizer 2, the fuel line L 1 branches into a fuel line L 11 that supplies hydrocarbon fuel to the reformer 7 and a fuel line L 12 that supplies hydrocarbon fuel to the burner combustor 8.
The fuel line L11 and the fuel line L12 are provided with electromagnetic valves 12 and 13 for switching the supply of hydrocarbon fuel to the reformer 7 and the burner combustor 8.
Furthermore, a water line L2 for supplying water (raw water) used for steam reforming to the reformer 7 is connected to the fuel line L11 in the vicinity of the reformer 7.
In addition, it is also possible to connect the fuel line L12 directly to the burner combustor 8 without going through the desulfurizer, and to supply the hydrocarbon fuel that has not been desulfurized to the burner combustor 8.
　前記水ラインＬ２の上流側には水タンク１５を連結し、また、水ラインＬ２には、改質器７への水の供給・停止を制御する電磁バルブ１４を設けてある。
　また、水タンク１５には、筐体６の外部から水タンク１５に水を供給する水ラインＬ２１、及び、ＰＥＦＣスタック４で反応により生成したプロセス水を回収する回収水ラインＬ２２を連結してある。 A water tank 15 is connected to the upstream side of the water line L2, and an electromagnetic valve 14 for controlling supply / stop of water to the reformer 7 is provided in the water line L2.
The water tank 15 is connected with a water line L21 for supplying water from the outside of the housing 6 to the water tank 15 and a recovery water line L22 for recovering process water generated by the reaction in the PEFC stack 4. .
　更に、水タンク１５には、バーナ燃焼器８が排出する燃焼ガス（排出ガス）が含む水を回収する回収水ラインＬ２３を連結してある。
　回収水ラインＬ２３を介した燃焼ガスからの水の回収は、バーナ燃焼器８において改質ガスを燃焼させた場合に行われるようになっている。 Further, the water tank 15 is connected with a recovered water line L23 for recovering water contained in the combustion gas (exhaust gas) discharged from the burner combustor 8.
The recovery of water from the combustion gas via the recovery water line L23 is performed when the reformed gas is burned in the burner combustor 8.
　これは、バーナ燃焼器８において炭化水素系燃料を燃焼させた場合の燃焼ガスに比べて、改質ガスを燃焼させた場合の燃焼ガスには油成分が少なく、不純物の少ない水を回収できるためである。
　また、筐体６の外部に設けた空気供給ブロワ４１からの空気をバーナ燃焼器８に供給するためのバーナ用空気ラインＬ３１を設けてある。 This is because the combustion gas when the reformed gas is burned has less oil components and water with less impurities can be recovered compared to the combustion gas when the hydrocarbon fuel is burned in the burner combustor 8. It is.
Further, a burner air line L31 for supplying air from an air supply blower 41 provided outside the housing 6 to the burner combustor 8 is provided.
　また、ＰＥＦＣスタック４は、改質ガス供給ラインＬ４を介してＦＰＳ３の選択酸化器１１に接続し、ＰＥＦＣスタック４は、選択酸化器１１を通過した改質ガスを、改質ガス供給ラインＬ４を介して導入する。
　また、ＰＥＦＣスタック４には、発電反応に寄与しなかった水素を含むオフガスを排出させるためのオフガス供給ラインＬ５を連結してあり、このオフガス供給ラインＬ５の下流側を、バーナ燃焼器８に連結し、オフガスをバーナ燃料としてバーナ燃焼器８に供給できるようになっている。 The PEFC stack 4 is connected to the selective oxidizer 11 of the FPS 3 via the reformed gas supply line L4. The PEFC stack 4 passes the reformed gas that has passed through the selective oxidizer 11 to the reformed gas supply line L4. Through.
The PEFC stack 4 is connected to an offgas supply line L5 for discharging offgas containing hydrogen that has not contributed to the power generation reaction. The downstream side of the offgas supply line L5 is connected to the burner combustor 8. In addition, the off-gas can be supplied to the burner combustor 8 as burner fuel.
　更に、改質ガス供給ラインＬ４の途中から分岐し、オフガス供給ラインＬ５の途中に接続するバイパスラインＬ１４を設けてある。
　そして、バイパスラインＬ１４に設けた電磁バルブ（バイパス弁）２６と、バイパスラインＬ１４の分岐部よりも下流側の改質ガス供給ラインＬ４に設けた電磁バルブ（改質ガス供給弁）２７とを制御することで、ＦＰＳ３が生成した改質ガスを、バーナ燃焼器８に供給する状態と、ＰＥＦＣスタック４に供給する状態とに切り替えることができるようになっている。 Further, a bypass line L14 is provided which branches from the middle of the reformed gas supply line L4 and is connected to the middle of the off gas supply line L5.
Then, an electromagnetic valve (bypass valve) 26 provided in the bypass line L14 and an electromagnetic valve (reformed gas supply valve) 27 provided in the reformed gas supply line L4 downstream from the branching portion of the bypass line L14 are controlled. Thus, the reformed gas generated by the FPS 3 can be switched between a state in which the reformed gas is supplied to the burner combustor 8 and a state in which the reformed gas is supplied to the PEFC stack 4.
　即ち、電磁バルブ２７を閉じ、電磁バルブ２６を開けると、選択酸化器１１を通過した改質ガスは、ＰＥＦＣスタック４をバイパスしてバーナ燃焼器８に供給される。一方、電磁バルブ２７を開け、電磁バルブ２６を閉じると、選択酸化器１１を通過した改質ガスはＰＥＦＣスタック４に供給され、ＰＥＦＣスタック４から排出されるオフガスが、バーナ燃焼器８に燃料として供給される。
　また、筐体６の外部に設けた空気供給ブロワ４２からの空気をＰＥＦＣスタック４に供給するためのスタック用空気ラインＬ３２を設けてあり、更に、筐体６の外部に設けた空気供給ブロワ４３からの空気（選択酸化用空気）を選択酸化器１１に供給するための選択酸化用空気ラインＬ３３を、選択酸化器１１に連結してある。 That is, when the electromagnetic valve 27 is closed and the electromagnetic valve 26 is opened, the reformed gas that has passed through the selective oxidizer 11 bypasses the PEFC stack 4 and is supplied to the burner combustor 8. On the other hand, when the electromagnetic valve 27 is opened and the electromagnetic valve 26 is closed, the reformed gas that has passed through the selective oxidizer 11 is supplied to the PEFC stack 4, and off-gas discharged from the PEFC stack 4 is supplied to the burner combustor 8 as fuel. Supplied.
In addition, a stack air line L32 for supplying air from the air supply blower 42 provided outside the housing 6 to the PEFC stack 4 is provided, and an air supply blower 43 provided outside the housing 6 is provided. The selective oxidizer 11 is connected to a selective oxidizer air line L33 for supplying air (selective oxidizer air) to the selective oxidizer 11.
　尚、選択酸化部１１から導出した改質ガス及びＰＥＦＣスタック４からのオフガスは、炭化水素ガスであるメタンを含有する場合があるが、炭化水素を含有しているガスであっても、Ｌ１４又はＬ５からバーナ燃焼器８が導入するガスは水素含有の改質ガスであるものとする。また、改質ガスを燃料としてバーナ燃焼器８（燃焼部）に供給する場合に、主成分としての改質ガスと共に、少量の炭化水素系燃料を同時にバーナ燃焼器８（燃焼部）に供給してもよい。
　マイクロプロセッサを内蔵した制御装置（制御部）３０は、上記の各電磁バルブ１２，１３，１４，２６，２７及び各ブロワ４１，４２，４３、更に、後述するイグナイタ２２などを制御して、燃料電池システムの動作を制御する。 Note that the reformed gas derived from the selective oxidation unit 11 and the off-gas from the PEFC stack 4 may contain methane, which is a hydrocarbon gas, but even if the gas contains hydrocarbons, L14 or The gas introduced by the burner combustor 8 from L5 is assumed to be a hydrogen-containing reformed gas. Further, when the reformed gas is supplied as fuel to the burner combustor 8 (combustion section), a small amount of hydrocarbon fuel is simultaneously supplied to the burner combustor 8 (combustion section) together with the reformed gas as the main component. May be.
A control device (control unit) 30 having a built-in microprocessor controls each of the electromagnetic valves 12, 13, 14, 26, 27 and the blowers 41, 42, 43, an igniter 22 described later, and the like. Control the operation of the battery system.
　次に、ＦＰＳ３の構造を詳細に説明する。
　図２は、ＦＰＳ３の断面図であり、この図２に示すように、バーナ燃焼器（燃焼部）８は、バーナ燃料（炭化水素系燃料、改質ガス、オフガス）を空気で燃焼するバーナ部１９、及び、バーナ火炎を保炎する燃焼筒２１を有している。 Next, the structure of the FPS 3 will be described in detail.
FIG. 2 is a cross-sectional view of the FPS 3. As shown in FIG. 2, the burner combustor (combustion unit) 8 is a burner unit that burns burner fuel (hydrocarbon fuel, reformed gas, offgas) with air. 19 and a combustion cylinder 21 for holding the burner flame.
　前記バーナ部１９には、燃料ラインＬ１２、バーナ用空気ラインＬ３１、オフガス供給ラインＬ５とバイパスラインＬ１４とが合流したラインを連結してあり、また、連続して点火動作を行える点火装置であるイグナイタ２２を備え、バーナ燃料は、イグナイタ２２の火花点火によって着火燃焼する。
　灯油などの液体の炭化水素系燃料を用いる場合、燃料ラインＬ１２又はバーナ燃焼器８の内部に気化器（図示省略）を配置し、灯油などの液体の炭化水素系燃料を気化器で気化させてから、燃焼筒２１に供給するようにする。 The burner unit 19 is connected to a fuel line L12, a burner air line L31, a line where an off-gas supply line L5 and a bypass line L14 merge, and an igniter which is an ignition device capable of performing an ignition operation continuously. The burner fuel is ignited and burned by spark ignition of the igniter 22.
When using liquid hydrocarbon fuel such as kerosene, a carburetor (not shown) is disposed inside the fuel line L12 or the burner combustor 8, and liquid hydrocarbon fuel such as kerosene is vaporized by the vaporizer. Then, the fuel is supplied to the combustion cylinder 21.
　燃焼筒２１は、バーナ燃焼空間Ｓを画定し、この燃焼筒２１で火炎が保炎される。また、この燃焼筒２１には、該燃焼筒２１内の温度ＴＢ（燃焼部の温度）を検出する燃焼温度センサ２３を設けてある。
　一方、燃焼筒２１の外側を囲むように、円筒状の改質器筐体２４を配置し、燃焼筒２１の外周面と、改質器筐体２４の内周面との間に、環状の触媒収容空間ＳＣを形成する。 The combustion cylinder 21 defines a burner combustion space S, and the flame is held in the combustion cylinder 21. The combustion cylinder 21 is provided with a combustion temperature sensor 23 for detecting the temperature TB (temperature of the combustion part) in the combustion cylinder 21.
On the other hand, a cylindrical reformer casing 24 is disposed so as to surround the outside of the combustion cylinder 21, and an annular shape is provided between the outer peripheral surface of the combustion cylinder 21 and the inner peripheral surface of the reformer casing 24. A catalyst housing space SC is formed.
　触媒収容空間ＳＣには、改質器筐体２４の内周面及び燃焼筒２１の外周面に対してそれぞれに隙間ＳＲ１，ＳＲ２を有して環状の改質触媒容器２５を挿置し、かつ、改質触媒容器２５のバーナ燃焼器８側の端面と、改質器筐体２４のバーナ燃焼器８側の端面との間に隙間ＳＲＥを設けてある。
　改質触媒容器２５には、例えば、ニッケル若しくはルテニウムを主成分とする改質触媒２５ａを充填してあり、脱硫処理後の炭化水素系燃料と水蒸気とからなる原料ガスを改質触媒２５ａで水蒸気改質反応させて、水素を含有する水蒸気改質ガスを生成する。 In the catalyst containing space SC, an annular reforming catalyst container 25 having gaps SR1, SR2 is inserted into the inner peripheral surface of the reformer casing 24 and the outer peripheral surface of the combustion cylinder 21, respectively. A gap SRE is provided between the end surface of the reforming catalyst container 25 on the burner combustor 8 side and the end surface of the reformer casing 24 on the burner combustor 8 side.
The reforming catalyst container 25 is filled with, for example, a reforming catalyst 25a mainly composed of nickel or ruthenium, and a raw material gas composed of a hydrocarbon-based fuel and steam after the desulfurization treatment is steamed by the reforming catalyst 25a. A reforming reaction is performed to generate a steam reformed gas containing hydrogen.
　改質触媒容器２５は、下方端から原料ガスを導入し、改質触媒２５ａで水蒸気改質反応して生成された水蒸気改質ガスは、改質触媒容器２５の上端側外周から改質触媒容器２５を囲む環状空間ＳＣ１に導出され、改質触媒容器２５の外側を下方に向けて流れ、改質触媒容器２５の下方に配置した変成器（変成部）９に導入される。
　一方、燃焼筒２１で発生した燃焼ガスは、燃焼筒２１の外周面と改質触媒容器２５の内周面とで挟まれる環状空間ＳＲ１を通って、バーナ燃焼器８側の端部に向けて移動した後、前記改質触媒容器２５のバーナ燃焼器８側の端面を回り込むようにして、改質器筐体２４の内周面と改質触媒容器２５の外周面とで挟まれる環状空間ＳＲ２に入り、前記環状空間ＳＲ２をバーナ燃焼器８から離れる方向（図２で下方）に移動した後、前記変成器９の外側の囲む環状空間ＳＲＥ１を介して外部に排出される。 The reforming catalyst container 25 introduces the raw material gas from the lower end, and the steam reformed gas generated by the steam reforming reaction with the reforming catalyst 25 a is generated from the outer periphery of the reforming catalyst container 25 at the upper end side. 25, is led out to the annular space SC1 surrounding 25, flows outwardly from the reforming catalyst container 25, and is introduced into a transformer (transformer) 9 disposed below the reforming catalyst container 25.
On the other hand, the combustion gas generated in the combustion cylinder 21 passes through the annular space SR <b> 1 sandwiched between the outer peripheral surface of the combustion cylinder 21 and the inner peripheral surface of the reforming catalyst container 25 toward the end on the burner combustor 8 side. After the movement, the annular space SR2 sandwiched between the inner peripheral surface of the reformer casing 24 and the outer peripheral surface of the reforming catalyst container 25 so as to go around the end surface of the reforming catalyst container 25 on the burner combustor 8 side. After moving in the annular space SR2 away from the burner combustor 8 (downward in FIG. 2), the annular space SR2 is discharged to the outside through the annular space SRE1 surrounding the transformer 9.
　更に、前記環状空間ＳＲＥ１の外側を囲むようにして、水タンク１５から供給される水を蒸発させる水蒸気発生器１６を設けてあり、この水蒸気発生器１６で発生した水蒸気を、改質触媒２５ａに導入される脱硫処理後の炭化水素系燃料に混入させるようになっている。
　変成器（変成部）９を通過した改質ガスは、途中で選択酸化用の空気を加えられた後、前記水蒸気発生器１６の外側を囲むようにして設けられた選択酸化器１１に導入され、ここで、一酸化炭素濃度が低減された後、後段（燃料電池スタック４又はバーナ燃焼器８）に供給される。
　尚、水タンク１５から供給される水は、選択酸化器１１から導出された直後の改質ガスとの間で熱交換を行った後、水蒸気発生器１６に供給されるようにしてある。 Further, a steam generator 16 for evaporating the water supplied from the water tank 15 is provided so as to surround the outside of the annular space SRE1, and the steam generated by the steam generator 16 is introduced into the reforming catalyst 25a. It is mixed with the hydrocarbon fuel after desulfurization treatment.
The reformed gas that has passed through the transformer (transformer section) 9 is added with selective oxidation air in the middle, and then introduced into the selective oxidizer 11 provided so as to surround the outside of the steam generator 16. Then, after the carbon monoxide concentration is reduced, it is supplied to the subsequent stage (the fuel cell stack 4 or the burner combustor 8).
The water supplied from the water tank 15 is supplied to the steam generator 16 after heat exchange with the reformed gas immediately after being derived from the selective oxidizer 11.
　上記のようにして、燃焼筒２１（燃焼部）で発生した高温の燃焼ガスが、改質触媒容器２５の内周面及び外周面に沿って流れることで、改質触媒容器２５内の改質触媒２５ａ及び原料ガスが、前記改質触媒２５ａにおける吸熱反応に必要な温度（例えば４００℃～８００℃）に加熱される。また、燃焼筒２１（燃焼部）で発生した燃焼ガスの熱は、変成器９のシフト触媒及び選択酸化器１１の選択酸化触媒の加熱に用いられ、更に、水蒸気発生器１６における熱源として用いられる。即ち、前記バーナ燃焼器８は、燃焼ガスによって触媒加熱を行う燃焼部である。
　制御装置３０は、起動スイッチ３１のオン・オフ信号、燃焼温度センサ２３が出力する燃焼温度信号ＴＢ、更に、選択酸化器１１の選択酸化触媒の温度ＴＣを検出する触媒温度センサ３２が出力する選択触媒温度信号ＴＣを入力する一方、電磁バルブ１２，１３，１４，２６，２７及び各ブロワ４１，４２，４３、更に、イグナイタ２２に対して操作信号を出力することで、バーナ燃焼器８に対する燃料及び空気の供給、改質器７に対する炭化水素系燃料及び原料水の供給、イグナイタ２２による点火動作、ＰＥＦＣスタック４への改質ガスの供給などを制御する。 As described above, the high-temperature combustion gas generated in the combustion cylinder 21 (combustion section) flows along the inner peripheral surface and the outer peripheral surface of the reforming catalyst container 25, so that the reforming in the reforming catalyst container 25 is performed. The catalyst 25a and the raw material gas are heated to a temperature (for example, 400 ° C. to 800 ° C.) necessary for the endothermic reaction in the reforming catalyst 25a. Further, the heat of the combustion gas generated in the combustion cylinder 21 (combustion section) is used for heating the shift catalyst of the shift converter 9 and the selective oxidation catalyst of the selective oxidizer 11 and further used as a heat source in the steam generator 16. . That is, the burner combustor 8 is a combustion section that performs catalyst heating with combustion gas.
The control device 30 outputs an ON / OFF signal of the start switch 31, a combustion temperature signal TB output from the combustion temperature sensor 23, and a selection output from a catalyst temperature sensor 32 that detects the temperature TC of the selective oxidation catalyst of the selective oxidizer 11. While inputting the catalyst temperature signal TC, the operation signals are output to the electromagnetic valves 12, 13, 14, 26, 27 and the blowers 41, 42, 43, and further to the igniter 22, thereby fuel for the burner combustor 8. And the supply of air, the supply of hydrocarbon fuel and raw water to the reformer 7, the ignition operation by the igniter 22, the supply of reformed gas to the PEFC stack 4, and the like are controlled.
　図３は、燃料電池システム１の起動時に、制御装置３０が実行する制御処理手順を示すフローチャートである。制御装置３０は、例えば、起動スイッチ３１のオン操作信号を入力したときに図３のフローチャートに示す処理を開始する。
　まず、電磁バルブ１３及び空気供給ブロワ４１を制御して、バーナ燃焼器８に炭化水素系燃料及び空気を供給し（Ｓ１１１）、イグナイタ２２によって着火燃焼させる。これにより、バーナ燃焼器８の燃焼排ガスが改質触媒２５ａを加熱する。 FIG. 3 is a flowchart showing a control processing procedure executed by the control device 30 when the fuel cell system 1 is started. For example, the control device 30 starts the process shown in the flowchart of FIG. 3 when an ON operation signal of the start switch 31 is input.
First, the solenoid valve 13 and the air supply blower 41 are controlled to supply hydrocarbon fuel and air to the burner combustor 8 (S111), and the igniter 22 performs ignition combustion. Thereby, the combustion exhaust gas of the burner combustor 8 heats the reforming catalyst 25a.
　ＦＰＳ３で改質ガスを生成するようになるまでは、バーナ燃焼器８に燃料として供給できる改質ガスが発生しないので、起動時はバーナ燃料として、改質処理の原燃料である灯油などの炭化水素系燃料を用い、改質熱を発生させる。
　燃料電池システム１の起動時に、バーナ燃焼器８において炭化水素系燃料を燃焼させれば、バーナ燃焼器８の温度ＴＢが常温から急激に上昇し、かつ、燃料としての炭化水素系燃料を安定して供給できるので、燃焼温度ＴＢの上昇速度が判定速度を超えていることや、燃焼温度ＴＢが着火判定温度を超えたことなどに基づいて、炭化水素系燃料の着火成功を高精度に判定できる。 The reformed gas that can be supplied as fuel to the burner combustor 8 is not generated until the reformed gas is generated by the FPS 3, so carbonization such as kerosene that is the raw fuel of the reforming process is used as the burner fuel at the start-up. Using hydrogen-based fuel, heat of reforming is generated.
If the hydrocarbon-based fuel is combusted in the burner combustor 8 when the fuel cell system 1 is started, the temperature TB of the burner combustor 8 rises rapidly from the normal temperature, and the hydrocarbon-based fuel as the fuel is stabilized. Therefore, the ignition success of the hydrocarbon fuel can be determined with high accuracy based on the fact that the rising speed of the combustion temperature TB exceeds the determination speed or the combustion temperature TB exceeds the ignition determination temperature. .
　そして、炭化水素系燃料の着火成功を判定すると、イグナイタ２２による火花点火を停止させる。
　バーナ燃焼器８における炭化水素系燃料の燃焼によって改質触媒２５ａの温度が吸熱反応に必要な温度にまで高まり、水蒸気発生器１６で水蒸気が発生できる温度まで高まると、ＦＰＳ３において改質ガスの生成を開始させるために、電磁バルブ１２，１４を制御して、改質器７に炭化水素系燃料及び原料水を供給する（Ｓ１１２）。 When the ignition success of the hydrocarbon fuel is determined, the spark ignition by the igniter 22 is stopped.
When the temperature of the reforming catalyst 25a rises to a temperature necessary for the endothermic reaction due to the combustion of the hydrocarbon fuel in the burner combustor 8, and the steam generator 16 rises to a temperature at which steam can be generated, the reformed gas is generated in the FPS3. In order to start the operation, the solenoid valves 12 and 14 are controlled to supply the hydrocarbon fuel and the raw water to the reformer 7 (S112).
　但し、改質器７に対する炭化水素系燃料及び原料水の供給を開始させるときには、選択酸化器１１に対する選択酸化用空気の供給を開始させず、後述するように、バーナ燃焼器８における改質ガスの着火成功を判定してから、選択酸化用空気の供給を開始させるようにしてある。
　従って、バーナ燃焼器８における改質ガスの着火成功を判定するまでは、選択酸化器１１における一酸化炭素の選択酸化は行われず、選択酸化の実行時よりも一酸化炭素濃度が高い改質ガスが選択酸化器１１から導出される。 However, when the supply of hydrocarbon fuel and raw material water to the reformer 7 is started, the supply of selective oxidation air to the selective oxidizer 11 is not started, and the reformed gas in the burner combustor 8 will be described later. After the successful ignition is determined, the supply of the selective oxidation air is started.
Accordingly, the selective oxidation of carbon monoxide in the selective oxidizer 11 is not performed until it is determined that ignition of the reformed gas in the burner combustor 8 is successful, and the reformed gas having a higher carbon monoxide concentration than when selective oxidation is performed. Is derived from the selective oxidizer 11.
　炭化水素系燃料及び原料水の供給によって、ＦＰＳ３が改質ガスを生成するようになると、バーナ燃料を炭化水素系燃料から改質ガスに移行させるために、まず、電磁バルブ１３を制御して、バーナ燃焼器８への炭化水素系燃料の供給を停止する（Ｓ１１３）。続いて、電磁バルブ２７を閉制御し、電磁バルブ２６を開制御し、選択酸化器１１を通過した改質ガスを、バイパスラインＬ１４を介して直接バーナ燃焼器８に供給する（Ｓ１１４）。
　また、空気供給ブロワ４１を制御して、改質ガスの燃焼に最適な空気の供給量に制御し、イグナイタ２２による連続した火花点火によって改質ガスを着火させる。 When the FPS 3 generates reformed gas due to the supply of hydrocarbon fuel and raw water, in order to shift the burner fuel from the hydrocarbon fuel to the reformed gas, first, the electromagnetic valve 13 is controlled, The supply of hydrocarbon fuel to the burner combustor 8 is stopped (S113). Subsequently, the electromagnetic valve 27 is closed and the electromagnetic valve 26 is opened, and the reformed gas that has passed through the selective oxidizer 11 is supplied directly to the burner combustor 8 via the bypass line L14 (S114).
In addition, the air supply blower 41 is controlled to control the air supply amount to be optimal for the combustion of the reformed gas, and the reformed gas is ignited by continuous spark ignition by the igniter 22.
　ここで、図５に示すように、改質ガスのバーナ燃焼器８への供給開始に先立って、イグナイタ２２による点火動作を開始させておくことが好ましい。
　尚、電磁バルブ２６，２７を制御して、改質ガスのバーナ燃焼器８への供給を開始し、続いて電磁バルブ１３を制御してバーナ燃焼器８への炭化水素系燃料の供給を停止させてもよく、この場合、炭化水素系燃料のみをバーナ燃焼器８に供給する状態から、炭化水素系燃料及び改質ガスをバーナ燃焼器８に供給する状態を過渡的に経て、改質ガスのみをバーナ燃焼器８に供給する状態に移行することになる。 Here, as shown in FIG. 5, it is preferable to start the ignition operation by the igniter 22 prior to the start of supply of the reformed gas to the burner combustor 8.
The electromagnetic valves 26 and 27 are controlled to start supplying reformed gas to the burner combustor 8, and then the electromagnetic valve 13 is controlled to stop supplying hydrocarbon fuel to the burner combustor 8. In this case, the state of supplying only the hydrocarbon-based fuel to the burner combustor 8 and the state of supplying the hydrocarbon-based fuel and the reformed gas to the burner combustor 8 are transited, and the reformed gas is supplied. Only the state is supplied to the burner combustor 8.
　ここで、電磁バルブ２６を開いて改質ガスのバーナ燃焼器８への供給を開始してからも、電磁バルブ２７を閉状態に保持するので、選択酸化器１１を通過した改質ガスは、ＰＥＦＣスタック４に供給されず、バーナ燃焼器８に供給されることになる。
　バーナ燃焼器８に対する改質ガスの供給を開始すると、バーナ燃焼器８において改質ガスの着火に成功したか否かの判定を行う（Ｓ１１５）。 Here, even after the electromagnetic valve 26 is opened and supply of the reformed gas to the burner combustor 8 is started, the electromagnetic valve 27 is kept closed, so that the reformed gas that has passed through the selective oxidizer 11 is Instead of being supplied to the PEFC stack 4, it is supplied to the burner combustor 8.
When supply of the reformed gas to the burner combustor 8 is started, it is determined whether or not the reformer gas has been successfully ignited in the burner combustor 8 (S115).
　係る着火判定の詳細は、図４のフローチャートに示してある。
　図４のフローチャートに示すルーチンは、燃焼温度のサンプリング周期毎（一定時間毎）に実行され、まず、燃焼温度変化の検出を開始させるタイミングであるか否かを判断する（ステップＳ２０１）。
　燃焼温度変化の検出開始タイミングは、例えば、炭化水素系燃料から改質ガスへの移行条件が成立した時点や、バーナ燃料の切替え処理に先立ってイグナイタ２２による点火動作を開始した時点や、バーナ燃料の切替え時から所定時間だけ前の時点や、炭化水素系燃料の供給遮断時点や、改質ガスの供給開始時点や、炭化水素系燃料の供給遮断時点又は改質ガスの供給開始時点から所定時間後に設定することができる。 The details of the ignition determination are shown in the flowchart of FIG.
The routine shown in the flowchart of FIG. 4 is executed at each combustion temperature sampling period (every fixed time), and first, it is determined whether or not it is time to start detection of combustion temperature change (step S201).
The detection start timing of the combustion temperature change is, for example, when the transition condition from the hydrocarbon-based fuel to the reformed gas is satisfied, when the ignition operation by the igniter 22 is started prior to the burner fuel switching process, For a predetermined time from a point in time before the changeover of the gas, a point at which the hydrocarbon fuel supply is cut off, a point at which the reformed gas supply is started, a point at which the hydrocarbon fuel supply is cut off, or the point at which the reformed gas supply is started. It can be set later.
　燃焼温度変化の検出開始タイミングになると、そのときに温度センサ２３が検出した燃焼筒２１内の温度（燃焼部の温度）ＴＢを読み込む（ステップＳ２０２）。
　次いで、燃焼温度変化の検出開始タイミングにおいて読み込んだ温度ＴＢを、初期値として最低温度Ｔminにセットする（ステップＳ２０３）。
　次いで、検出開始タイミングからの経過時間が最大判定時間（例えば４分～１０分程度）に達しているか否か、換言すれば、炭化水素系燃料から改質ガスへの移行後の時期に設定した判定終了タイミングに達しているか否かを判断する（ステップＳ２０４）。 When it becomes the detection start timing of the combustion temperature change, the temperature (combustion part temperature) TB detected by the temperature sensor 23 at that time is read (step S202).
Next, the temperature TB read at the detection start timing of the combustion temperature change is set to the minimum temperature Tmin as an initial value (step S203).
Next, whether or not the elapsed time from the detection start timing has reached the maximum judgment time (for example, about 4 to 10 minutes), in other words, the time after the transition from the hydrocarbon-based fuel to the reformed gas is set. It is determined whether or not the determination end timing has been reached (step S204).
　前記検出開始タイミングから最大判定時間が経過した時点を、着火判定の終了タイミングとするものであり、前記検出開始タイミングからの経過時間が最大判定時間に達していなければ、改質ガスの供給状態で着火に成功したか否かを判断させるべく、前記温度センサ２３が検出した燃焼筒２１内の温度（燃焼部の温度）ＴＢを読み込む（ステップＳ２０５）。
　そして、前回までの最低温度Ｔminと、今回のサンプリングタイミングで検出した燃焼部の温度ＴＢとを比較し（ステップＳ２０６）、前回までの最低温度Ｔminよりも今回検出した燃焼部の温度ＴＢが低ければ、今回検出した燃焼部の温度ＴＢを最低温度Ｔminにセットする（ステップＳ２０７）。これにより、失火による温度降下中であれば、最低温度Ｔminを、サンプリング周期毎に最新の検出温度に更新することになる。 The time when the maximum determination time has elapsed from the detection start timing is set as the ignition determination end timing, and if the elapsed time from the detection start timing has not reached the maximum determination time, the reformed gas is supplied. In order to determine whether or not ignition has succeeded, the temperature (combustion part temperature) TB in the combustion cylinder 21 detected by the temperature sensor 23 is read (step S205).
Then, the lowest temperature Tmin until the previous time is compared with the temperature TB of the combustion part detected at the current sampling timing (step S206), and if the temperature TB of the combustion part detected this time is lower than the lowest temperature Tmin until the previous time. Then, the temperature TB of the combustion section detected this time is set to the minimum temperature Tmin (step S207). As a result, if the temperature is decreasing due to misfire, the minimum temperature Tmin is updated to the latest detected temperature every sampling cycle.
　一方、今回検出した燃焼部の温度ＴＢが前回までの最低温度Ｔmin以上であれば、最低温度Ｔminの更新は行わず、今回検出した燃焼部の温度ＴＢから前回までの最低温度Ｔminを減算した温度（最低温度Ｔminからの最新温度の上昇幅）が、閾値ΔＴ（例えば５℃～１０℃程度）以上であるか否かを判断する（ステップＳ２０８）。換言すれば、今回の着火判定タイミング（サンプリングタイミング）において温度センサ２３が検出した燃焼部の温度ＴＢがそれまでの最低温度（最低値）Ｔminよりも閾値ΔＴ以上に高いか否かを判断する。 On the other hand, if the temperature TB of the combustion section detected this time is equal to or higher than the minimum temperature Tmin until the previous time, the minimum temperature Tmin is not updated, and the temperature obtained by subtracting the minimum temperature Tmin until the previous time from the temperature TB of the combustion section detected this time. It is determined whether or not (the increase range of the latest temperature from the minimum temperature Tmin) is equal to or greater than a threshold value ΔT (for example, about 5 ° C. to 10 ° C.) (step S208). In other words, it is determined whether or not the temperature TB of the combustion portion detected by the temperature sensor 23 at the current ignition determination timing (sampling timing) is higher than the threshold ΔT by a minimum temperature (minimum value) Tmin.
　前記最低温度Ｔminを更新した場合（Ｔmin＞Ｔであった場合）、及び、Ｔmin≦Ｔであって、かつ、今回検出した燃焼部の温度ＴＢから前回までの最低温度Ｔminを減算した温度が閾値ΔＴ未満であると判断された場合には、再度、最大判定時間に達したか否かを判断する処理（ステップＳ２０４）に戻る。
　これにより、最大判定時間に達するまでは、微小時間間隔（一定周期）の着火判定タイミング毎に、前回までの最低温度Ｔminと今回検出した燃焼部の温度ＴＢとを比較して、最低温度Ｔminの更新処理を行い、また、Ｔmin≦Ｔであった場合には最低温度Ｔminと今回検出した燃焼部の温度ＴＢとの比較を繰り返す。 When the minimum temperature Tmin is updated (when Tmin> T), and Tmin ≦ T and the temperature obtained by subtracting the previous minimum temperature Tmin from the temperature TB of the combustion section detected this time is a threshold value When it is determined that it is less than ΔT, the process returns to the process of determining whether or not the maximum determination time has been reached (step S204).
Thus, until the maximum determination time is reached, the minimum temperature Tmin until the previous time is compared with the temperature TB of the combustion portion detected this time at every minute time interval (constant period) ignition determination timing, and the minimum temperature Tmin Update processing is performed. If Tmin ≦ T, the comparison between the lowest temperature Tmin and the temperature TB of the combustion section detected this time is repeated.
　このため、前記最低温度Ｔminは、温度変化の検出開始タイミングから今回の着火判定タイミング（サンプリングタイミング）までの間における燃焼部の温度ＴＢの最低値を示すことになる。
　そして、今回検出した燃焼部の温度ＴＢから前回までの最低温度Ｔminを減算した温度（最低温度Ｔminからの最新温度の上昇幅）が、閾値ΔＴ以上であると判断した場合には、改質ガスの着火成功を判定する（ステップＳ２０９）。 For this reason, the minimum temperature Tmin indicates the minimum value of the temperature TB of the combustion section between the temperature change detection start timing and the current ignition determination timing (sampling timing).
When it is determined that the temperature obtained by subtracting the previous minimum temperature Tmin from the temperature TB of the combustion section detected this time (the rise in the latest temperature from the minimum temperature Tmin) is equal to or greater than the threshold value ΔT, the reformed gas Is determined to be successful (step S209).
　換言すれば、今回の着火判定タイミングにおいて温度センサ２３が検出した燃焼部の温度ＴＢが、検出開始タイミング（炭化水素系燃料から改質ガスへの切り替え時）から今回（現時点）までの間における最低温度（最低値）Ｔminよりも閾値ΔＴ以上に高いと判断すると、改質ガスの着火成功を判定する。
　着火成功を判定すると、その後遅れてイグナイタ２２の点火動作を停止させる。 In other words, the temperature TB of the combustion part detected by the temperature sensor 23 at the current ignition determination timing is the lowest between the detection start timing (when switching from the hydrocarbon-based fuel to the reformed gas) and this time (current time). If it is determined that the temperature (minimum value) Tmin is higher than the threshold value ΔT, it is determined whether the reformed gas has been successfully ignited.
When it is determined that the ignition has succeeded, the ignition operation of the igniter 22 is stopped later.
　一方、着火判定を開始してからの経過時間が前記最大判定時間に達するまでの間に（着火判定の終了タイミングになるまでの間に）、一定周期毎に最低温度Ｔminと検出温度ＴＢとの比較を繰り返しても、改質ガスの着火成功を判定しなかった場合には、最大判定時間に達するまでの間の最低温度Ｔminと、改質ガスの供給状態での下限燃焼温度Ｔｈとを比較する（ステップＳ２１０）。
　前記下限燃焼温度Ｔｈは、改質ガスを燃焼させたときの燃焼部温度ＴＢの下限値であり、改質ガスが継続して燃焼していれば、燃焼部の温度ＴＢが下回ることがない温度である。 On the other hand, between the minimum temperature Tmin and the detected temperature TB for each fixed period until the elapsed time from the start of the ignition determination reaches the maximum determination time (until the end timing of the ignition determination). If the success of ignition of the reformed gas is not determined even after repeated comparisons, the minimum temperature Tmin until the maximum determination time is reached and the lower limit combustion temperature Th in the reformed gas supply state are compared. (Step S210).
The lower limit combustion temperature Th is the lower limit value of the combustion part temperature TB when the reformed gas is combusted. If the reformed gas is continuously combusted, the temperature at which the temperature TB of the combustion part does not fall below It is.
　最大判定時間に達した時点、即ち、判定終了タイミングにおける最低温度Ｔminが、下限燃焼温度Ｔｈ以上である場合には、燃料を炭化水素系燃料から改質ガスに切替えてから最大判定時間が経過するまでの間、燃焼部の温度ＴＢが一度も下限燃焼温度Ｔｈを下回らず、下限燃焼温度Ｔｈ以上の温度を維持したことを示す。
　前述のように、下限燃焼温度Ｔｈは、改質ガスが継続して燃焼していれば、燃焼部の温度ＴＢが下回ることがない温度であるから、最大判定時間だけ下限燃焼温度Ｔｈ以上の温度を維持していた場合には、改質ガスの着火に成功し、安定した改質ガスの燃焼状態を維持しているものと推定できるので、改質ガスの着火成功を判定する（ステップＳ２０９）。 When the maximum determination time is reached, that is, when the minimum temperature Tmin at the determination end timing is equal to or higher than the lower limit combustion temperature Th, the maximum determination time elapses after the fuel is switched from the hydrocarbon-based fuel to the reformed gas. In the meantime, it is shown that the temperature TB of the combustion part has never fallen below the lower limit combustion temperature Th and has maintained a temperature equal to or higher than the lower limit combustion temperature Th.
As described above, the lower limit combustion temperature Th is a temperature at which the temperature TB of the combustion section does not fall below the reformed gas if the reformed gas continues to burn. If it has been maintained, it can be estimated that the reformed gas has been successfully ignited and the stable reformed gas combustion state is maintained, so that the reformed gas has been successfully ignited (step S209). .
　一方、判定終了タイミングにおける最低温度Ｔminが下限燃焼温度Ｔｈ未満であった場合には、最大判定時間が経過するまでの間に、燃焼部温度ＴＢが下限燃焼温度Ｔｈ未満になったことがあること、換言すれば、一時的であったとしても失火が発生したことを示すから、着火に成功したとは判定できず、しかも、最低温度（最低値）Ｔminから閾値ΔＴ以上の温度上昇が最大判定時間内で発生しなかったので、既定時間内で着火状態に至らなかった着火失敗（タイムアウト：着火処理の時間切れ）を判定する（ステップＳ２１１）。
　着火失敗（タイムアウト）を判定すると、アラーム（警告）を発し、脱硫器２・ＦＰＳ３への空気・炭化水素系燃料・原料水の供給を停止させ、燃料電池システムをリセットする。 On the other hand, when the minimum temperature Tmin at the determination end timing is lower than the lower limit combustion temperature Th, the combustion section temperature TB may have become lower than the lower limit combustion temperature Th until the maximum determination time elapses. In other words, even if it is temporary, it indicates that a misfire has occurred. Therefore, it cannot be determined that the ignition has succeeded, and the temperature rise from the minimum temperature (minimum value) Tmin to the threshold ΔT or more is determined to be the maximum. Since it did not occur within the time, an ignition failure (timeout: time-out of the ignition process) that did not reach the ignition state within the predetermined time is determined (step S211).
If ignition failure (timeout) is determined, an alarm (warning) is issued, the supply of air, hydrocarbon fuel, and raw water to the desulfurizer 2 and FPS 3 is stopped, and the fuel cell system is reset.
　次に、上記の着火判定処理の作用を、図５のタイムチャートを参照しつつ説明する。
　図５のタイムチャートは、バーナ燃焼器８に供給するバーナ燃料を、炭化水素系燃料から改質ガスに移行させたときの温度変化の一例を示す。
　尚、図５では、バーナ燃料を炭化水素系燃料（灯油）とする工程を工程１とし、その後のバーナ燃料を改質ガス（オフガスを含む）とする工程を工程２として示してある。 Next, the effect | action of said ignition determination process is demonstrated, referring the time chart of FIG.
The time chart of FIG. 5 shows an example of a temperature change when the burner fuel supplied to the burner combustor 8 is transferred from the hydrocarbon-based fuel to the reformed gas.
In FIG. 5, the step of using the burner fuel as a hydrocarbon-based fuel (kerosene) is shown as step 1, and the subsequent step of using the burner fuel as a reformed gas (including off-gas) is shown as step 2.
　図５に示す例では、時刻ｔ２において、バーナ燃料を炭化水素系燃料から改質ガスに切り替えるが、該移行時点（切り替え時点）ｔ２よりも前の時刻ｔ１から、イグナイタ２２による点火動作を開始させ、改質ガスの着火性能を確保できるようにしている。
　時刻ｔ２において、炭化水素系燃料の供給を停止させ、略同時に改質ガスの供給を開始させ、バーナ燃料を、炭化水素系燃料から改質ガスに切り替えると、直後は、炭化水素系燃料と改質ガスとの混焼状態となり、燃焼部の温度ＴＢは、切り替え以前の炭化水素系燃料の燃焼時における温度（例えば７５０℃程度）よりも一時的に上昇する場合がある。図５に示す例では、時刻ｔ２から時刻ｔ３までの間が、混焼による温度上昇期間である。 In the example shown in FIG. 5, the burner fuel is switched from the hydrocarbon-based fuel to the reformed gas at time t2, but the ignition operation by the igniter 22 is started from time t1 before the transition time (switching time) t2. The ignition performance of the reformed gas can be ensured.
At time t2, when the supply of the hydrocarbon fuel is stopped and the supply of the reformed gas is started substantially simultaneously, and the burner fuel is switched from the hydrocarbon fuel to the reformed gas, immediately after that, the hydrocarbon fuel is changed. There is a case where the temperature TB of the combustion part temporarily rises above the temperature (for example, about 750 ° C.) at the time of combustion of the hydrocarbon-based fuel before switching. In the example shown in FIG. 5, the period from time t2 to time t3 is a temperature increase period due to mixed firing.
　但し、改質ガスへの切り替え直後は、バーナ燃焼器８に対する改質ガスの供給が安定せず、改質ガスの供給が一時的に滞ったりすることでバーナ燃焼器８が失火し、燃焼部の温度ＴＢが降下することがある。図５に示す例では、時刻ｔ３から時刻ｔ４までの間が、改質ガスの供給が一時的に滞ったことなどによる燃焼部の温度降下期間である。
　炭化水素系燃料の供給停止に先立って改質ガスの供給を開始させ、改質ガスの燃焼が安定化するのを待って、炭化水素系燃料の供給停止を行えば、過渡的な失火を抑制してバーナ燃料の切り替えを行えるが、この場合、混焼時間が長くなることで、過剰な温度上昇を招くことがある。 However, immediately after switching to the reformed gas, the supply of the reformed gas to the burner combustor 8 is not stable, and the burner combustor 8 is misfired due to a temporary stagnation of the supply of the reformed gas. Temperature TB may drop. In the example shown in FIG. 5, the period from time t3 to time t4 is a temperature drop period of the combustion section due to a temporary stagnation of the reformed gas supply.
Prior to stopping the supply of hydrocarbon fuel, start the supply of reformed gas, wait until the reformed gas combustion stabilizes, and stop the supply of hydrocarbon fuel to suppress transient misfires. Then, the burner fuel can be switched. In this case, however, an excessive temperature increase may be caused by the prolonged mixed firing time.
　そこで、温度の過剰上昇を回避すべく、混焼時間を短くすると、改質ガスの供給が不安定な状態で改質ガス単独の燃焼に移行することになり、これによって失火が生じ、図５の時刻ｔ３から時刻ｔ４までの間に示されるような温度降下が発生することがある。
　上記のような失火による温度降下の間も、イグナイタ２２による点火動作を継続する一方で、時間経過に伴って改質ガスの供給安定性が改善されるため、着火に成功し、そのまま改質ガスの安定燃焼状態に移行する場合があるが、一時的に着火したものの直ぐに失火状態に戻ってしまう場合もあり、図５に示す例では、時刻ｔ４で着火による温度上昇に転じたものの直ぐに失火し、時刻ｔ５から再度温度が降下し始める場合を示す。 Therefore, if the co-firing time is shortened in order to avoid an excessive rise in temperature, the reformed gas supply shifts to combustion with the reformed gas alone in an unstable state. A temperature drop as shown between time t3 and time t4 may occur.
While the ignition operation by the igniter 22 is continued during the temperature drop due to the misfire as described above, the supply stability of the reformed gas is improved with time, so that the ignition is successful and the reformed gas is directly maintained. However, in the example shown in FIG. 5, although the temperature started to rise due to ignition at the time t4, it immediately misfired. The case where the temperature starts to fall again from time t5 is shown.
　また、図５に示す例では、時刻ｔ６の時点で着火しその後安定的な改質ガスの燃焼状態を保持するため、燃焼部の温度ＴＢが時刻ｔ６の時点から漸増し、最終的に、改質ガスの燃焼状態での安定温度付近（例えば７３０℃程度）に収束している。
　本実施形態の着火判定では、最低温度Ｔminに対する上昇幅が閾値ΔＴ以上の場合に着火の成功を判定する構成であり、例えば、図５に示す例では、前記最低温度Ｔminは、時刻ｔ３までは、炭化水素系燃料をバーナ燃料とする場合の燃焼部の温度（例えば７５０℃程度）に保持されることになり、バーナ燃料の切り替えに伴う混焼状態で温度上昇すると、燃焼部の温度ＴＢは最低温度Ｔminを超える温度になる。 Further, in the example shown in FIG. 5, in order to ignite at the time t6 and thereafter maintain a stable reformed gas combustion state, the temperature TB of the combustion section gradually increases from the time t6, and finally, the reformed gas is improved. It converges around a stable temperature (for example, about 730 ° C.) in the combustion state of the gas.
The ignition determination according to the present embodiment is configured to determine the success of ignition when the increase width with respect to the minimum temperature Tmin is equal to or greater than the threshold value ΔT. For example, in the example illustrated in FIG. 5, the minimum temperature Tmin is until time t3. When the hydrocarbon-based fuel is burner fuel, the temperature of the combustion section (for example, about 750 ° C.) is maintained, and when the temperature rises in the mixed combustion state accompanying the switching of the burner fuel, the temperature TB of the combustion section is the lowest The temperature exceeds the temperature Tmin.
　但し、閾値ΔＴとして、混焼状態による温度上昇分を上回るような値を予め設定し、混焼による温度上昇に対しては、着火成功を判定しないようにしてある。換言すれば、混焼による温度上昇が、閾値ΔＴ以上になることがないように、バーナ燃料の切り替えが行われるようにしてある。
　混焼状態の後で、改質ガスの供給が滞ることで、燃焼部の温度ＴＢが降下すると、これに応じて最低温度Ｔminをより低い温度に更新し、一時的な着火による温度上昇が発生する直前の時刻ｔ４の時点では、この時刻ｔ４での検出温度ＴＢを最低温度Ｔminにセットすることになる。 However, as the threshold value ΔT, a value that exceeds the temperature rise due to the co-firing state is set in advance, and the successful ignition is not determined for the temperature rise due to co-firing. In other words, the burner fuel is switched so that the temperature rise due to mixed combustion does not exceed the threshold value ΔT.
If the temperature TB of the combustion section decreases due to the supply of the reformed gas after the co-firing state, the minimum temperature Tmin is updated to a lower temperature accordingly, and a temperature increase due to temporary ignition occurs. At the time immediately before time t4, the detected temperature TB at time t4 is set to the minimum temperature Tmin.
　一時的な着火による温度上昇が発生すると、時刻ｔ４での検出温度ＴＢである最低温度Ｔminよりも温度が高くなるが、係る一時的な温度上昇に対しても着火成功を判定しないように、前記閾値ΔＴを予め設定してあり、一時的な着火によって温度がピーク値を示す時刻ｔ５における温度ＴＢでも、時刻ｔ４での検出温度である最低温度Ｔminに対する相対比較に基づいて着火成功を判定することはない。
　そして、一時的な着火状態から失火状態に戻り、温度ＴＢが漸減すると、これに応じて最低温度Ｔminをより低い温度に更新し、時刻ｔ６の時点では、そのときの検出温度ＴＢを最低温度Ｔminに設定する。 When a temperature increase due to temporary ignition occurs, the temperature becomes higher than the minimum temperature Tmin that is the detected temperature TB at time t4, but the ignition success is not determined for such temporary temperature increase. A threshold value ΔT is set in advance, and the ignition success is determined based on a relative comparison with the minimum temperature Tmin that is the detected temperature at the time t4 even at the temperature TB at the time t5 when the temperature reaches a peak value due to temporary ignition. There is no.
When the temperature TB returns gradually from the temporary ignition state to the misfire state, the minimum temperature Tmin is updated to a lower temperature accordingly. At time t6, the detected temperature TB at that time is changed to the minimum temperature Tmin. Set to.
　前記時刻ｔ６の後の温度上昇過程で、周期的に最低温度Ｔmin（時刻ｔ６での検出温度）と最新の検出温度ＴＢとを比較し、最終的に、時刻ｔ６での温度ＴＢよりも閾値ΔＴ以上に高くなった時点（時刻ｔ７）において着火成功を判定する。
　換言すれば、前記閾値ΔＴは、混焼や一時的な着火による温度上昇で着火成功を判定することがなく、かつ、失火状態から安定した燃焼状態に移行し順調に温度上昇して初めて着火成功を判定するように、予め適合してある。 In the temperature rising process after time t6, the lowest temperature Tmin (detected temperature at time t6) is periodically compared with the latest detected temperature TB, and finally the threshold ΔT is higher than the temperature TB at time t6. The ignition success is determined at the time (time t7) when the temperature becomes higher than the above.
In other words, the threshold value ΔT does not determine whether ignition has succeeded due to a temperature rise due to mixed combustion or temporary ignition, and succeeds in ignition only after the transition from the misfire state to the stable combustion state and the temperature rises smoothly. Pre-adapted to determine.
　そして、着火成功を判定した時刻ｔ７から予め設定した遅延時間が経過した時点である時刻ｔ８において、イグナイタ２２による点火動作を停止する。
　このように、最低温度Ｔminからの上昇幅に基づいて着火成功を判定する構成であるから、例えば、時刻ｔ２，時刻ｔ４，時刻ｔ６直後の温度上昇率（温度上昇速度）が同程度であったとしても、時刻ｔ２，時刻ｔ４からの温度上昇では、最終的に到達する最高温度と時刻ｔ２，時刻ｔ４での温度ＴＢとの偏差が閾値ΔＴ未満であり、着火成功を判定しない。 Then, the ignition operation by the igniter 22 is stopped at a time t8 when a preset delay time has elapsed from the time t7 when it was determined that ignition was successful.
Thus, since it is the structure which determines ignition success based on the raise range from minimum temperature Tmin, the temperature rise rate (temperature rise speed) immediately after time t2, time t4, and time t6 was comparable, for example. However, in the temperature rise from time t2 and time t4, the deviation between the highest temperature finally reached and the temperature TB at time t2 and time t4 is less than the threshold value ΔT, and successful ignition is not determined.
　一方、時刻ｔ６からの温度上昇では、時刻ｔ６での温度ＴＢを起点として、実際に着火に成功したことに基づいて順調に温度上昇することで、時刻ｔ６での温度ＴＢよりも閾値ΔＴ以上に高い温度ＴＢにまで上昇し、閾値ΔＴ以上の温度上昇を判定した時点（時刻ｔ７）において、着火成功を判定する。
　換言すれば、実際に着火に成功したことに基づいて順調に温度上昇すれば、仮に、温度上昇勾配が、混焼による温度上昇や一時的な着火による温度上昇時よりも緩やかであったとしても、着火成功を判定することができる。 On the other hand, in the temperature rise from time t6, starting from the temperature TB at time t6, the temperature rises smoothly on the basis of the fact that ignition was actually successful, so that the temperature ΔB exceeds the threshold value ΔT above the temperature TB at time t6. When the temperature rises to a high temperature TB and a temperature rise equal to or greater than the threshold value ΔT is determined (time t7), the ignition success is determined.
In other words, if the temperature rises smoothly based on the fact that ignition has actually succeeded, even if the temperature rise gradient is more gradual than when the temperature rises due to mixed firing or temporary ignition, Successful ignition can be determined.
　尚、今回検出した燃焼部の温度ＴＢから前回までの最低温度Ｔminを減算した温度（最低温度Ｔminからの最新温度の上昇幅）が、閾値ΔＴ以上である状態が、予め設定した時間を超えて継続したときに、最終的に着火成功を判定するようにしてもよい。
　また、着火判定手段・方法を、上記の最低温度からの上昇幅で判定する構成に限定するものではなく、公知の種々の着火判定手段・方法を適用でき、例えば、温度センサ２３が検出した燃焼部の温度ＴＢの時間微分値（温度の上昇速度）が閾値を超えたときに着火成功を判定することができ、また、複数の温度センサ２３によって複数個所で温度検出を行って着火成功を判定させることができ、更に、温度以外の状態量、例えば圧力や燃焼排気の成分濃度などに基づいて着火成功を判定させることもできる。 It should be noted that a state in which the temperature obtained by subtracting the previous minimum temperature Tmin from the temperature TB of the combustion section detected this time (the latest temperature rise from the minimum temperature Tmin) is equal to or greater than the threshold ΔT exceeds the preset time. When the operation is continued, the ignition success may be finally determined.
Further, the ignition determination means / method is not limited to the above-described configuration for determining by the range from the minimum temperature, and various known ignition determination means / methods can be applied. For example, the combustion detected by the temperature sensor 23 Successful ignition can be determined when the time differential value (temperature rise rate) of the part temperature TB exceeds a threshold value, and temperature detection is performed at a plurality of locations by a plurality of temperature sensors 23 to determine successful ignition. Furthermore, it is possible to determine the success of ignition based on a state quantity other than temperature, for example, pressure or a component concentration of combustion exhaust gas.
　改質ガスの着火成功又はタイムアウト（着火失敗）を判定するまでは、着火判定を繰り返し、着火成功を判定すると、触媒温度センサ３２が検出した選択酸化器１１の選択酸化触媒の温度ＴＣが、選択酸化用空気の供給開始を許容する温度領域（許容温度領域）内であるか否かを判定する（Ｓ１１６）。
　許容温度領域の最低温度は、選択酸化用空気の供給を開始させた場合に、選択酸化触媒の雰囲気中に酸素が残存して選択酸化触媒を酸化させてしまうことがない最低温度であり、許容温度領域の最高温度は、選択酸化用空気の供給開始に伴うメタネーション暴走の発生による触媒劣化を抑制できる最高温度であり、許容温度領域は、例えば、９０℃～２１０℃程度とする。 The ignition determination is repeated until the reformed gas ignition success or timeout (ignition failure) is determined. When the ignition success is determined, the temperature TC of the selective oxidation catalyst of the selective oxidizer 11 detected by the catalyst temperature sensor 32 is selected. It is determined whether or not the temperature is within a temperature range (allowable temperature range) in which the supply start of the oxidizing air is allowed (S116).
The minimum temperature in the allowable temperature range is the minimum temperature at which oxygen does not remain in the atmosphere of the selective oxidation catalyst and oxidize the selective oxidation catalyst when the supply of selective oxidation air is started. The maximum temperature in the temperature range is the maximum temperature at which catalyst deterioration due to the occurrence of methanation runaway upon the start of the supply of selective oxidation air can be suppressed, and the allowable temperature range is, for example, about 90 ° C. to 210 ° C.
　即ち、選択酸化触媒の温度ＴＣが、許容温度領域を外れている状態（９０℃以下、又は、２１０℃以上）で、選択酸化器１１に対する選択酸化用空気の供給を開始させてしまうと、選択酸化触媒の酸化やメタネーション暴走を発生させることになる。
　そこで、選択酸化触媒の温度ＴＣが、選択酸化用空気の供給開始を許容する温度領域内になるまでは温度判定を繰り返して、選択酸化用空気の供給開始を許容できる温度に上昇又は降下するまで待機する。 That is, if the supply of selective oxidation air to the selective oxidizer 11 is started in a state where the temperature TC of the selective oxidation catalyst is outside the allowable temperature range (90 ° C. or less, or 210 ° C. or more), the selection is performed. Oxidation of the oxidation catalyst and methanation runaway will occur.
Therefore, the temperature determination is repeated until the temperature TC of the selective oxidation catalyst falls within the temperature range in which the supply of selective oxidation air is allowed to be started, until the temperature rises or falls to a temperature that allows the supply of selective oxidation air to be permitted. stand by.
　選択酸化触媒の温度ＴＣが、許容温度領域の最高温度よりも高い場合には、選択酸化触媒に配設した冷却管内に水を循環させて、選択酸化触媒を冷却し、選択酸化触媒の温度ＴＣを低下させるようにする。
　また、選択酸化触媒の温度ＴＣが、許容温度領域の最低温度よりも低い場合には、選択酸化触媒の近傍に設けたヒータによる加熱を行って温度上昇させることができる他、バーナ燃焼器８の燃焼排ガスを選択酸化触媒の周囲に導いて選択酸化触媒を加熱させる構成であってもよい。 When the temperature TC of the selective oxidation catalyst is higher than the maximum temperature in the allowable temperature range, the selective oxidation catalyst is cooled by circulating water in the cooling pipe provided in the selective oxidation catalyst, and the temperature TC of the selective oxidation catalyst. To lower.
In addition, when the temperature TC of the selective oxidation catalyst is lower than the lowest temperature in the allowable temperature range, the temperature can be increased by heating with a heater provided in the vicinity of the selective oxidation catalyst. The combustion exhaust gas may be guided around the selective oxidation catalyst to heat the selective oxidation catalyst.
　選択酸化触媒の温度ＴＣが、許容温度領域内であれば、それまで停止させていた選択酸化器１１に対する選択酸化用空気の供給を開始させ、選択酸化器１１における一酸化炭素ＣＯの選択酸化を開始させる（Ｓ１１７）。
　選択酸化器１１に対する選択酸化用空気の供給を開始し、改質ガス中のＣＯ濃度が選択酸化で低下するようになると、選択酸化器１１から導出される改質ガスのＰＥＦＣスタック４のアノードへの供給を開始させ、また、空気供給ブロワ４２を制御して、ＰＥＦＣスタック４のカソードへの空気の供給を開始させる（Ｓ１１８）。 If the temperature TC of the selective oxidation catalyst is within the allowable temperature range, the supply of selective oxidation air to the selective oxidizer 11 that has been stopped is started, and the selective oxidation of the carbon monoxide CO in the selective oxidizer 11 is started. Start (S117).
When the supply of selective oxidation air to the selective oxidizer 11 is started and the CO concentration in the reformed gas is reduced by selective oxidation, the reformed gas derived from the selective oxidizer 11 is supplied to the anode of the PEFC stack 4. Is started, and the air supply blower 42 is controlled to start supplying air to the cathode of the PEFC stack 4 (S118).
　即ち、図５に示すように、バーナ燃焼器８における改質ガスの着火成功を時刻ｔ７において判定すると、この時刻ｔ７の時点で、選択酸化器１１に対する選択酸化用空気の供給を開始し、更に、時刻ｔ７の時点、若しくは、時刻ｔ７から予め設定された遅れ時間ＴＤが経過した時点で、バイパスラインＬ１４を閉じ、ＰＥＦＣスタック４のアノードへの改質ガスの供給を開始させる。前記遅れ時間ＴＤは、選択酸化用空気の供給開始から、選択酸化器１１におけるＣＯの選択酸化が充分に行われるようになるまでの時間に相当する。
　換言すれば、選択酸化用空気の供給開始と略同時に、又は、選択酸化用空気の供給開始から一定時間後に、アノードへの改質ガスの供給を開始させる。 That is, as shown in FIG. 5, when successful ignition of the reformed gas in the burner combustor 8 is determined at time t7, supply of selective oxidation air to the selective oxidizer 11 is started at time t7, and further At time t7 or when a preset delay time TD has elapsed from time t7, the bypass line L14 is closed and supply of reformed gas to the anode of the PEFC stack 4 is started. The delay time TD corresponds to the time from the start of the supply of selective oxidation air until the selective oxidation of CO in the selective oxidizer 11 is sufficiently performed.
In other words, the supply of the reformed gas to the anode is started substantially simultaneously with the start of the supply of the selective oxidation air or after a predetermined time from the start of the supply of the selective oxidation air.
　選択酸化用空気の供給開始前（改質ガスの着火成功の判定前）は、電磁バルブ２６を開き、電磁バルブ２７を閉じておくことで、選択酸化器１１を通過した改質ガスを直接バーナ燃焼器８に供給し、選択酸化用空気の供給開始後（改質ガスの着火成功の判定後）は、電磁バルブ２６を閉じ、電磁バルブ２７を開くことで、選択酸化器１１を通過した改質ガスをＰＥＦＣスタック４のアノードに供給し、アノードを通過したオフガスを、バーナ燃焼器８に供給する。
　尚、ＰＥＦＣスタック４への発電用空気の供給の開始は、ＰＥＦＣスタック４への改質ガスの供給開始から遅らせてもよい。
　その後、ＰＥＦＣスタック４が所定の温度まで昇温した後、ＰＥＦＣスタック４から電流を取り出すことにより、ＰＥＦＣスタック４による発電を開始する。 Prior to the start of the supply of selective oxidation air (before the determination of successful reformed gas ignition), the electromagnetic valve 26 is opened and the electromagnetic valve 27 is closed so that the reformed gas that has passed through the selective oxidizer 11 is directly burned. After supplying to the combustor 8 and starting the supply of the selective oxidation air (after the determination of the successful ignition of the reformed gas), the electromagnetic valve 26 is closed and the electromagnetic valve 27 is opened, so that the reforming that has passed through the selective oxidizer 11 is performed. The quality gas is supplied to the anode of the PEFC stack 4, and the off gas that has passed through the anode is supplied to the burner combustor 8.
Note that the start of supply of power generation air to the PEFC stack 4 may be delayed from the start of supply of the reformed gas to the PEFC stack 4.
Thereafter, after the temperature of the PEFC stack 4 is raised to a predetermined temperature, power is taken out from the PEFC stack 4 by taking out a current from the PEFC stack 4.
　上記のように、上記起動処理では、バーナ燃焼器８における改質ガスの着火成功を判定してから、選択酸化器１１に対する選択酸化用空気の供給を開始する。
　ここで、選択酸化器１１を通過した改質ガスをバーナ燃焼器８に供給するから、バーナ燃焼器８において改質ガスの着火成功を判定したことは、選択酸化器１１に改質ガスが到達し、かつ、安定的に供給されていることを示す。
　従って、バーナ燃焼器８における改質ガスの着火成功を判定してから、選択酸化器１１に対する選択酸化用空気の供給を開始させれば、選択酸化器１１に改質ガスが到達する前に選択酸化用空気の供給を開始させてしまうことを回避できる。 As described above, in the start-up process, after the successful ignition of the reformed gas in the burner combustor 8 is determined, the supply of selective oxidation air to the selective oxidizer 11 is started.
Here, since the reformed gas that has passed through the selective oxidizer 11 is supplied to the burner combustor 8, the fact that the reformer gas has been successfully ignited in the burner combustor 8 has reached the selective oxidizer 11. In addition, it shows that it is supplied stably.
Therefore, if the supply of the selective oxidation air to the selective oxidizer 11 is started after determining the successful ignition of the reformed gas in the burner combustor 8, the reformed gas is selected before reaching the selective oxidizer 11. It is possible to avoid starting the supply of the oxidizing air.
　選択酸化器１１に改質ガスが到達する前に選択酸化用空気の供給を開始させてしまうと、たとえ、選択酸化触媒の温度ＴＣが選択酸化用空気の供給開始を許容できる温度領域内であったとしても、選択酸化用空気が含む酸素によって選択酸化触媒の活性金属が酸化してしまう。
　その後、選択酸化器１１に改質ガスが到達することで選択酸化反応が始まり、活性金属は還元されるが、酸化・還元を繰り返すことで活性金属が劣化する。 If the supply of selective oxidation air is started before the reformed gas reaches the selective oxidizer 11, even if the temperature TC of the selective oxidation catalyst is within a temperature range in which the supply of selective oxidation air can be permitted to start. Even so, the active metal of the selective oxidation catalyst is oxidized by the oxygen contained in the selective oxidation air.
Thereafter, the selective oxidation reaction starts when the reformed gas reaches the selective oxidizer 11 and the active metal is reduced. However, the active metal deteriorates by repeated oxidation and reduction.
　これに対し、本実施形態では、選択酸化器１１に改質ガスが到達する前に選択酸化用空気の供給を開始させてしまうことがないから、選択酸化用空気の供給によって選択酸化触媒の活性金属を酸化させることがなく、以って、酸化・還元を繰り返すことによる活性金属の劣化を防止し、選択酸化触媒の触媒作用を安定的に発揮させることができる。
　また、本実施形態では、バーナ燃焼器８における改質ガスの着火成功を判定したことに加え、選択酸化触媒の温度が許容温度領域内であることを条件に、選択酸化用空気の供給を開始させるから、低温条件での選択酸化用空気の供給による活性金属の酸化、及び、高温条件での選択酸化用空気の供給による活性金属の過熱を防止できる。 On the other hand, in this embodiment, since the supply of the selective oxidation air is not started before the reformed gas reaches the selective oxidizer 11, the activity of the selective oxidation catalyst is increased by the supply of the selective oxidation air. Without oxidizing the metal, the deterioration of the active metal due to repeated oxidation and reduction can be prevented, and the catalytic action of the selective oxidation catalyst can be exhibited stably.
In this embodiment, in addition to determining the successful ignition of the reformed gas in the burner combustor 8, the supply of the selective oxidation air is started on the condition that the temperature of the selective oxidation catalyst is within the allowable temperature range. Therefore, the oxidation of the active metal due to the supply of the selective oxidation air under the low temperature condition and the overheating of the active metal due to the supply of the selective oxidation air under the high temperature condition can be prevented.
　以上、本発明の好適な実施形態について詳細に説明したが、本発明は上記実施形態に限定されるものではない。
　例えば、上記実施形態では、バーナ燃焼器８（燃焼部）に用いる炭化水素系燃料として灯油を例示したが、この他、ガソリン、ナフサ、軽油、メタノール、エタノール、ジメチルエーテル、バイオマスを利用したバイオ燃料を用いてもよく、更に、炭化水素系燃料は液体燃料に限定されず、都市ガスなどの気体燃料であってもよい。 The preferred embodiment of the present invention has been described in detail above, but the present invention is not limited to the above embodiment.
For example, in the above embodiment, kerosene is exemplified as the hydrocarbon fuel used in the burner combustor 8 (combustion unit), but in addition, biofuel using gasoline, naphtha, light oil, methanol, ethanol, dimethyl ether, and biomass is used. Further, the hydrocarbon fuel is not limited to the liquid fuel, and may be a gaseous fuel such as city gas.
　また、燃焼部の温度ＴＢは、燃焼部に供給する燃料だけでなく温度センサ２３の取り付け位置（センシング位置）によっても異なるため、図５に記載の温度変遷傾向に限定されない。
　また、上記実施形態では、ＰＥＦＣスタック４を備えた燃料電池システム１としたが、固体酸化物形燃料電池（ＳＯＦＣ）スタックを備えた燃料電池システムでもよい。 Further, the temperature TB of the combustion part is not limited to the temperature transition tendency shown in FIG. 5 because it varies depending not only on the fuel supplied to the combustion part but also on the attachment position (sensing position) of the temperature sensor 23.
Moreover, in the said embodiment, although it was set as the fuel cell system 1 provided with the PEFC stack 4, the fuel cell system provided with the solid oxide fuel cell (SOFC) stack may be sufficient.
　また、例えば、改質器７と変成器９とを一体的に形成したり、改質器７と変成器９と選択酸化部１１とを一体的に形成したり、脱硫器２と改質器７と変成器９とを一体的に形成したりすることができる。
　また、バーナ燃焼器８を、変成器９が備えるシフト触媒（例えばＦｅ－Ｃｒの混合酸化物）の加熱用として用い、このバーナ燃焼器８に選択酸化器１１を通過した改質ガスを燃料として供給する構成であってもよい。 Further, for example, the reformer 7 and the transformer 9 are integrally formed, the reformer 7, the transformer 9 and the selective oxidation unit 11 are integrally formed, or the desulfurizer 2 and the reformer. 7 and the transformer 9 can be integrally formed.
Further, the burner combustor 8 is used for heating a shift catalyst (for example, a mixed oxide of Fe—Cr) provided in the converter 9, and the reformed gas that has passed through the selective oxidizer 11 is used as fuel for the burner combustor 8. The structure which supplies may be sufficient.
　１…燃料電池システム１、３…燃料処理システム（ＦＰＳ）、４…固体高分子形燃料電池（ＰＥＦＣ）スタック、７…改質器（改質部）、８…バーナ燃焼器（燃焼部）、９…変成器（変性部）、１１…選択酸化器（選択酸化部）、２１…燃焼筒、２２…イグナイタ（点火装置）、２３…燃焼温度センサ、３０…制御装置（制御部）、３２…触媒温度センサ DESCRIPTION OF SYMBOLS 1 ... Fuel cell system 1, 3 ... Fuel processing system (FPS), 4 ... Polymer electrolyte fuel cell (PEFC) stack, 7 ... Reformer (reforming part), 8 ... Burner combustor (combustion part), DESCRIPTION OF SYMBOLS 9 ... Transformer (denaturing part), 11 ... Selective oxidizer (selective oxidation part), 21 ... Combustion cylinder, 22 ... Igniter (ignition device), 23 ... Combustion temperature sensor, 30 ... Control device (control part), 32 ... Catalyst temperature sensor

Claims (14)

  1. 　改質触媒を用いて炭化水素系燃料から水素を含有する改質ガスを生成する改質部と、
    　前記改質部が生成した改質ガスが含む一酸化炭素をシフト反応により低減するシフト触媒を備えた変性部と、
    　選択酸化触媒を備え、前記変性部を通過した改質ガスが含む一酸化炭素を、選択酸化用空気の供給によって選択酸化して低減する選択酸化部と、
    　前記選択酸化部に対して選択酸化用空気を供給する空気供給部と、
    　前記選択酸化部を通過した改質ガスを導入する触媒加熱用の燃焼部と、
    　前記選択酸化部を通過した改質ガスを導入する燃料電池スタックと、
    　を含む燃料電池システムであって、
    　前記燃焼部における改質ガスの着火判定を行ない、改質ガスの着火成功の判定後に、前記空気供給部による前記選択酸化部への選択酸化用空気の供給を開始させる制御部を備えた燃料電池システム。     A reforming unit that generates a reformed gas containing hydrogen from a hydrocarbon-based fuel using a reforming catalyst;
    A modifying unit comprising a shift catalyst that reduces carbon monoxide contained in the reformed gas generated by the reforming unit by a shift reaction;
    A selective oxidation unit that includes a selective oxidation catalyst, and selectively oxidizes carbon monoxide contained in the reformed gas that has passed through the denaturing unit by supplying selective oxidation air; and
    An air supply unit for supplying selective oxidation air to the selective oxidation unit;
    A combustion section for heating the catalyst that introduces the reformed gas that has passed through the selective oxidation section;
    A fuel cell stack for introducing the reformed gas that has passed through the selective oxidation unit;
    A fuel cell system comprising:
    A fuel cell comprising a control unit that performs ignition determination of reformed gas in the combustion unit and starts supply of selective oxidation air to the selective oxidation unit by the air supply unit after determination of successful ignition of the reformed gas system.
  2. 　前記制御部が、前記選択酸化部への選択酸化用空気の供給開始と略同時、又は、前記選択酸化部への選択酸化用空気の供給開始から一定時間後に、前記燃料電池スタックへの改質ガスの供給を開始させる請求項１記載の燃料電池システム。 The control unit reforms the fuel cell stack substantially simultaneously with the start of the supply of the selective oxidation air to the selective oxidation unit or after a certain time from the start of the supply of the selective oxidation air to the selective oxidation unit. The fuel cell system according to claim 1, wherein gas supply is started.
  3. 　前記制御部が、前記燃料電池スタックをバイパスして改質ガスを前記燃焼部に供給するラインを閉じて、前記燃料電池スタックへの改質ガスの供給を開始させる請求項２記載の燃料電池システム。 3. The fuel cell system according to claim 2, wherein the control unit closes a line that bypasses the fuel cell stack and supplies reformed gas to the combustion unit, and starts supply of the reformed gas to the fuel cell stack. .
  4. 　前記選択酸化部を通過した改質ガスを前記燃料電池スタックに供給する改質ガス供給ラインと、
    　前記燃料電池スタックからのオフガスを前記燃焼部に供給するオフガス供給ラインと、
    　前記改質ガス供給ラインとオフガス供給ラインとを接続するバイパスラインと、
    　前記バイパスラインに設けたバイパス弁と、
    　前記バイパスラインの接続部よりも下流側の前記改質ガス供給ラインに設けた改質ガス供給弁と、
    　を備え、
    　前記制御部は、前記改質ガス供給弁を閉、前記バイパス弁を開に制御して、前記燃料電池スタックをバイパスして改質ガスを前記燃焼部に供給し、前記改質ガス供給弁を開、前記バイパス弁を閉に制御して、前記燃料電池スタックへの改質ガスの供給を開始する請求項３記載の燃料電池システム。     A reformed gas supply line for supplying the reformed gas that has passed through the selective oxidation unit to the fuel cell stack;
    An offgas supply line for supplying offgas from the fuel cell stack to the combustion unit;
    A bypass line connecting the reformed gas supply line and the off-gas supply line;
    A bypass valve provided in the bypass line;
    A reformed gas supply valve provided in the reformed gas supply line on the downstream side of the connecting portion of the bypass line;
    With
    The control unit closes the reformed gas supply valve and controls the bypass valve to open, bypasses the fuel cell stack, supplies reformed gas to the combustion unit, and controls the reformed gas supply valve. The fuel cell system according to claim 3, wherein the supply of the reformed gas to the fuel cell stack is started by controlling the opening and the bypass valve to be closed.
  5. 　前記選択酸化触媒の温度を検出する触媒温度センサを備え、
    　前記制御部は、前記燃焼部における改質ガスの着火成功を判定し、かつ、前記選択酸化触媒の温度が、選択酸化用空気の供給開始を許容する所定温度領域内である場合に、前記空気供給部による前記選択酸化部への選択酸化用空気の供給を開始する請求項１記載の燃料電池システム。     A catalyst temperature sensor for detecting the temperature of the selective oxidation catalyst;
    The control unit determines whether the reformed gas has been successfully ignited in the combustion unit, and the temperature of the selective oxidation catalyst is within a predetermined temperature range that allows the supply of selective oxidation air to be started. The fuel cell system according to claim 1, wherein supply of selective oxidation air to the selective oxidation unit by a supply unit is started.
  6. 　前記所定温度領域が、前記選択酸化触媒の温度が９０℃～２１０℃の領域である請求項５記載の燃料電池システム。 6. The fuel cell system according to claim 5, wherein the predetermined temperature region is a region where the temperature of the selective oxidation catalyst is 90 ° C. to 210 ° C.
  7. 　前記燃焼部の温度を検出する燃焼温度センサを備え、
    　前記制御部は、前記燃焼部に供給する燃料を、前記炭化水素系燃料から前記改質ガスに移行させ、前記改質ガスの供給開始後から周期的なサンプリングタイミングまでの間における前記燃焼部の温度の最低値を検出し、前記最低値からの温度上昇幅が閾値を上回った場合に、改質ガスの着火成功を判定する請求項１記載の燃料電池システム。     A combustion temperature sensor for detecting the temperature of the combustion section;
    The control unit shifts the fuel supplied to the combustion unit from the hydrocarbon-based fuel to the reformed gas, and after the start of the supply of the reformed gas until the periodic sampling timing, 2. The fuel cell system according to claim 1, wherein the minimum value of the temperature is detected, and the successful ignition of the reformed gas is determined when the temperature rise from the minimum value exceeds a threshold value.
  8. 　改質触媒を用いて炭化水素系燃料から水素を含有する改質ガスを生成する改質部と、
    　前記改質部が生成した改質ガスが含む一酸化炭素をシフト反応により低減するシフト触媒を備えた変性部と、
    　選択酸化触媒を備え、前記変性部を通過した改質ガスが含む一酸化炭素を、選択酸化用空気の供給によって選択酸化して低減する選択酸化部と、
    　前記選択酸化部に対して選択酸化用空気を供給する空気供給部と、
    　前記選択酸化部を通過した改質ガスを導入して燃焼させる触媒加熱用の燃焼部と、
    　前記選択酸化部を通過した改質ガスを導入する燃料電池スタックと、
    　を備えた燃料電池システムの制御方法であって、
    　前記燃焼部における改質ガスの着火判定を行ない、
    　改質ガスの着火成功を判定した後に、前記空気供給部による前記選択酸化部への選択酸化用空気の供給を開始する燃料電池システムの制御方法。     A reforming unit that generates a reformed gas containing hydrogen from a hydrocarbon-based fuel using a reforming catalyst;
    A modifying unit comprising a shift catalyst that reduces carbon monoxide contained in the reformed gas generated by the reforming unit by a shift reaction;
    A selective oxidation unit that includes a selective oxidation catalyst, and selectively oxidizes carbon monoxide contained in the reformed gas that has passed through the denaturing unit by supplying selective oxidation air; and
    An air supply unit for supplying selective oxidation air to the selective oxidation unit;
    A combustion section for heating the catalyst that introduces and burns the reformed gas that has passed through the selective oxidation section;
    A fuel cell stack for introducing the reformed gas that has passed through the selective oxidation unit;
    A control method for a fuel cell system comprising:
    Make an ignition judgment of the reformed gas in the combustion section,
    A control method for a fuel cell system, wherein after the successful ignition of the reformed gas is determined, the supply of selective oxidation air to the selective oxidation unit by the air supply unit is started.
  9. 　前記選択酸化部への選択酸化用空気の供給開始と略同時、又は、前記選択酸化部への選択酸化用空気の供給開始から一定時間後に、前記燃料電池スタックへの改質ガスの供給を開始させるステップを更に含む請求項８記載の燃料電池システムの制御方法。 The reformed gas supply to the fuel cell stack is started substantially simultaneously with the start of the supply of the selective oxidation air to the selective oxidation unit or after a certain time from the start of the supply of the selective oxidation air to the selective oxidation unit. The method of controlling a fuel cell system according to claim 8, further comprising a step of:
  10. 　前記燃料電池スタックへの改質ガスの供給を開始するステップが、
    　前記燃料電池スタックをバイパスして改質ガスを前記燃焼部に供給するラインを閉じて、前記燃料電池スタックへの改質ガスの供給を開始させる請求項９記載の燃料電池システムの制御方法。     Starting the supply of reformed gas to the fuel cell stack,
    The method for controlling a fuel cell system according to claim 9, wherein a supply line of the reformed gas to the fuel cell stack is started by closing a line that bypasses the fuel cell stack and supplies the reformed gas to the combustion unit.
  11. 　前記燃料電池システムが、
    　前記選択酸化部を通過した改質ガスを前記燃料電池スタックに供給する改質ガス供給ラインと、
    　前記燃料電池スタックからのオフガスを前記燃焼部に供給するオフガス供給ラインと、
    　前記改質ガス供給ラインとオフガス供給ラインとを接続するバイパスラインと、
    　前記バイパスラインに設けたバイパス弁と、
    　前記バイパスラインの接続部よりも下流側の前記改質ガス供給ラインに設けた改質ガス供給弁と、
    　を備え、
    　前記燃料電池スタックへの改質ガスの供給を開始するステップが、
    　前記改質ガス供給弁を閉、前記バイパス弁を開に制御して、前記燃料電池スタックをバイパスして改質ガスを前記燃焼部に供給し、
    　前記改質ガス供給弁を開、前記バイパス弁を閉に制御して、前記燃料電池スタックへの改質ガスの供給を開始する請求項１０記載の燃料電池システムの制御方法。     The fuel cell system is
    A reformed gas supply line for supplying the reformed gas that has passed through the selective oxidation unit to the fuel cell stack;
    An offgas supply line for supplying offgas from the fuel cell stack to the combustion unit;
    A bypass line connecting the reformed gas supply line and the off-gas supply line;
    A bypass valve provided in the bypass line;
    A reformed gas supply valve provided in the reformed gas supply line on the downstream side of the connecting portion of the bypass line;
    With
    Starting the supply of reformed gas to the fuel cell stack,
    Closes the reformed gas supply valve, controls the bypass valve to open, bypasses the fuel cell stack, and supplies reformed gas to the combustion unit,
    The control method of a fuel cell system according to claim 10, wherein the reformed gas supply valve is opened and the bypass valve is controlled to be closed to start supply of the reformed gas to the fuel cell stack.
  12. 　前記選択酸化用空気の供給を開始するステップが、
    　前記選択酸化触媒の温度を検出し、
    　前記選択酸化触媒の温度が、選択酸化用空気の供給開始を許容する所定温度領域内であるか否かを判断し、
    　前記燃焼部における改質ガスの着火成功を判定し、かつ、前記選択酸化触媒の温度が前記所定温度領域内である場合に、前記空気供給部による前記選択酸化部への選択酸化用空気の供給を開始する請求項８記載の燃料電池システムの制御方法。     Starting the supply of the selective oxidation air,
    Detecting the temperature of the selective oxidation catalyst;
    It is determined whether the temperature of the selective oxidation catalyst is within a predetermined temperature range that allows the supply of selective oxidation air to start,
    Supply of selective oxidation air to the selective oxidation unit by the air supply unit when successful ignition of the reformed gas in the combustion unit is determined and the temperature of the selective oxidation catalyst is within the predetermined temperature range The method of controlling a fuel cell system according to claim 8, wherein the control is started.
  13. 　前記所定温度領域が、前記選択酸化触媒の温度が９０℃～２１０℃の領域である請求項１２記載の燃料電池システムの制御方法。 13. The fuel cell system control method according to claim 12, wherein the predetermined temperature region is a region where the temperature of the selective oxidation catalyst is 90 ° C. to 210 ° C.
  14. 　前記燃焼部に供給する燃料を、前記炭化水素系燃料から前記改質ガスに移行させるステップを更に備え、
    　前記着火判定を行うステップが、
    　前記燃焼部の温度を検出し、
    　前記燃焼部に対する改質ガスの供給開始後から周期的なサンプリングタイミングまでの間における前記燃焼部の温度の最低値を検出し、
    　前記最低値からの温度上昇幅が閾値を上回っているか否かを判定し、
    　前記温度上昇幅が閾値を上回った場合に、改質ガスの着火成功を判定する請求項８記載の燃料電池システムの制御方法。     Further comprising the step of transferring the fuel supplied to the combustion section from the hydrocarbon fuel to the reformed gas,
    Performing the ignition determination,
    Detecting the temperature of the combustion section;
    Detecting the minimum value of the temperature of the combustion section between the start of supply of the reformed gas to the combustion section and the periodic sampling timing;
    It is determined whether the temperature rise from the minimum value exceeds a threshold value,
    9. The control method for a fuel cell system according to claim 8, wherein when the temperature increase width exceeds a threshold value, the successful ignition of the reformed gas is determined.
PCT/JP2011/057414 2010-03-29 2011-03-25 Fuel cell system and control method for fuel cell system WO2011122485A1 (en)

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