WO2022113397A1 - Système de pile à combustible - Google Patents

Système de pile à combustible Download PDF

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Publication number
WO2022113397A1
WO2022113397A1 PCT/JP2021/014395 JP2021014395W WO2022113397A1 WO 2022113397 A1 WO2022113397 A1 WO 2022113397A1 JP 2021014395 W JP2021014395 W JP 2021014395W WO 2022113397 A1 WO2022113397 A1 WO 2022113397A1
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Prior art keywords
gas
containing gas
anode
catalytic reactor
heat exchanger
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PCT/JP2021/014395
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English (en)
Japanese (ja)
Inventor
雄斗 脇田
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三浦工業株式会社
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Publication of WO2022113397A1 publication Critical patent/WO2022113397A1/fr

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/04—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
    • H01M8/04223—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids during start-up or shut-down; Depolarisation or activation, e.g. purging; Means for short-circuiting defective fuel cells
    • H01M8/04225—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids during start-up or shut-down; Depolarisation or activation, e.g. purging; Means for short-circuiting defective fuel cells during start-up
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/04—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
    • H01M8/04223—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids during start-up or shut-down; Depolarisation or activation, e.g. purging; Means for short-circuiting defective fuel cells
    • H01M8/04228—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids during start-up or shut-down; Depolarisation or activation, e.g. purging; Means for short-circuiting defective fuel cells during shut-down
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/04—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
    • 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
    • H01M8/04007—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids related to heat exchange
    • H01M8/04014—Heat exchange using gaseous fluids; Heat exchange by combustion of reactants
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/30—Hydrogen technology
    • Y02E60/50—Fuel cells

Definitions

  • the present invention relates to a fuel cell system using a solid oxide fuel cell.
  • the fuel gas (city gas 13A) containing methane as the main component is reformed in the system to obtain hydrogen-containing gas for power generation. Is common.
  • the anode off gas generated by the power generation of the fuel cell stack 6 is cooled by the cathode supply air in the heat exchanger 10, and the water obtained by dehumidifying by the condenser 12 is used as a water tank.
  • Store in 21 This stored water is supplied to the evaporator 19 by the water pump 22 to become steam, which is mixed with the fuel gas and sent to the reformer 18.
  • hydrogen and carbon monoxide are generated from methane by the steam reforming reaction and supplied to the anode of the fuel cell stack 6.
  • a part of the anode off gas (regenerated gas from which water has been removed) separated by the condenser 12 is supplied to the anode of the fuel cell stack 6 by the recirculation blower 13.
  • a large number of peripheral devices such as a heat exchanger 10, a condenser 12, an evaporator 19, a water tank 21 and a water pump 22 are provided for collecting condensed water and generating steam.
  • the system of this embodiment has a high initial cost due to a complicated configuration, and also makes it difficult to reduce the size of the system package.
  • Patent Document 2 discloses a configuration of a fuel cell system that can partially solve the problems of Patent Document 1.
  • the system includes a reformer 14 for hydrogen-containing gas generation, a combustor 18 for off-gas treatment, a heat exchanger 20 for air preheating, and an anode off-gas recycling passage 38.
  • the combustor 18 is filled with a combustion catalyst, and both are connected to directly supply the combustion exhaust gas from the combustor 18 to the heat exchanger 20.
  • the reformer 14 functions as a partial oxidation reformer (POX) at system startup and as an autothermal reformer (AR) at steady state. That is, the anode off-gas is recycled only during the steady state when power generation is performed.
  • POX partial oxidation reformer
  • AR autothermal reformer
  • hydrogen-containing gas is generated by partial oxidation reforming or autothermal reforming to reduce auxiliary machinery related to condensed water recovery and steam generation. Further, by connecting the combustor 18 and the heat exchanger 20, the man-hours for assembling the piping work are reduced.
  • the reformer 14 of the present document internally ignites a mixed gas of raw fuel and air at the time of starting to perform thermal partial oxidation, and there is a concern that the reforming catalyst may be burned by flame formation.
  • the combustor 18 of the present document conducts catalytic combustion of air and reducing gas by self-ignition or ignition, but when the system is in a cold state, the cell is generated by the high-temperature reducing gas generated by partial oxidation reforming. Until the temperature rise of the stack 12 and sufficient preheating of the combustion catalyst are completed, there is a risk that the combustion of the catalyst cannot be performed and the flammable reducing gas leaks to the outside.
  • Patent Document 3 discloses a configuration of a fuel cell system that can partially solve the problems of Patent Document 1.
  • the system includes a reformer 5 for hydrogen-containing gas generation, a combustor 9 for off-gas treatment, a burner 12 for starting, a blower 24 for fuel recirculation, and heat exchangers 93 and 95 for air preheating. It is configured (Embodiment 3).
  • the reformer 5 has a partial oxidation catalyst and produces a partial oxidation gas used for preheating and raising the temperature of the fuel cell 7 at the start of the system.
  • the burner 12 is burned at startup of the system and uses the air heated by heat exchange with the combustion exhaust gas in the heat exchanger 93 to preheat the partial oxidation catalyst. A part of the heated air is also used for preheating the air electrode 31 and the electrolyte 33.
  • a hydrogen-containing gas is generated by an internal reforming reaction at the fuel electrode 35.
  • the partially oxidized gas having a temperature higher than the operating temperature at the time of power generation continues to be supplied to the anode, even if the temperature of the fuel cell 7 is raised.
  • the present invention has been made in view of the above problems, and an object of the present invention is to deactivate or damage the cell stack induced by oxidation or overheating of the anode in the temperature raising operation of the system start-up operation and the temperature lowering operation of the shutdown operation. It is to provide a fuel cell system in which the above is avoided. Another object is to provide a fuel cell system in which the initial cost can be suppressed and the system package can be easily miniaturized.
  • the fuel cell system includes a cell stack of a solid oxide fuel cell composed of a plurality of power generation cells composed of a solid electrolyte, an anode and a cathode, and a catalytic reactor in which a partial oxidation catalyst is arranged inside.
  • a recycling means capable of supplying the anode off gas discharged from the anode to the catalytic reactor, a power conditioner for converting the electric power generated by the cell stack, and a system controller for controlling the system operation.
  • the system controller supplies the first hydrocarbon-containing gas and the first oxidizing agent-containing gas to the catalytic reactor to generate the hydrogen-containing gas, and transfers the hydrogen-containing gas to the anode.
  • the system controller activates the recycling means, and the system controller gives the catalytic reactor a first hydrocarbon-containing gas and a first oxidizing agent-containing gas in the shutdown operation of the system.
  • the hydrogen-containing gas is supplied to the anode while the hydrogen-containing gas is generated, and the recycling means is operated during the reaction operation of the catalytic reactor.
  • the fuel cell system comprises a single combustion means for burning a second hydrocarbon-containing gas and / or an anode off gas together with a cathode off gas discharged from the cathode, and a combustion exhaust gas of the single combustion means. It is preferable to provide a gas preheater for preheating the second oxidizing agent-containing gas using the gas.
  • the catalytic reactor is configured as a two-fluid indirect heat exchanger in which the partial oxidation catalyst is arranged in one flow path, and the system controller is used in the start-up operation of the system before the reaction operation of the catalytic reactor.
  • the second oxidant-containing gas While burning the second hydrocarbon-containing gas with the single combustion means, the second oxidant-containing gas is circulated through the gas preheater, and the second oxidant-containing gas heated by the gas preheater is used. Is circulated in the flow path on the side of the indirect heat exchanger where the partial oxidation catalyst is not arranged to impart a part of combustion heat to the partial oxidation catalyst, and the second indirect heat exchanger is cooled. It is desirable to supply the oxidant-containing gas to the cathode.
  • the catalytic reactor is configured as a two-fluid indirect heat exchanger in which the partial oxidation catalyst is arranged in one flow path, and the system controller is the catalytic reactor in the start-up operation and / or shutdown operation of the system.
  • the second oxidant-containing gas is circulated in the flow path on the side of the indirect heat exchanger on the side where the partial oxidation catalyst is not arranged, and a part of the reaction heat accompanying the generation of the hydrogen-containing gas is recovered. It is desirable that the hydrogen-containing gas cooled by the indirect heat exchanger is supplied to the anode and the second oxidizing agent-containing gas heated by the indirect heat exchanger is supplied to the cathode.
  • the second oxidant-containing gas to be distributed to the indirect heat exchanger may be a gas in which all or part of the gas preheater is bypassed.
  • the system controller supplies the first hydrocarbon-containing gas to the catalytic reactor while operating the recycling means, and contains zero according to the sweep current of the cell stack. It is desirable to supply the required amount of the first oxidizing agent-containing gas to the catalytic reactor.
  • a fuel cell that avoids deactivation or damage of the cell stack induced by oxidation or overheating of the anode in the temperature raising operation in the start-up operation and the temperature lowering operation in the shutdown operation of the system.
  • the system can be provided.
  • FIG. 1 is an explanatory diagram showing the configuration of the fuel cell system 100 according to the first embodiment.
  • the fuel cell system 100 includes a cell stack 1, a catalytic reactor 2, a burner 3, an air preheater 4, a premixer 5, a power conditioner 6, and a system controller 7. , Equipped with.
  • the fuel cell system 100 is configured as a power generation system for business use or home use that can supply power to a building in a grid connection with a commercial power source.
  • a hydrocarbon-containing gas G1 (methane-containing gas such as city gas 13A) flows through the first fuel line L11 and the second fuel line L12.
  • the first fuel line L11 is a pipeline connecting the fuel inlet P10 and the fuel supply port of the premixer 5, and the first blower 11 is arranged in this pipeline.
  • the first blower 11 is a device that boosts the pressure of the first hydrocarbon-containing gas G1 and supplies it to the premixer 5.
  • a desulfurizer and a gas filter are provided on the discharge side of the first blower 11 as needed.
  • the second fuel line L12 is a pipeline connecting the first fuel line L11 on the upstream side of the first blower 11 and the fuel supply port of the burner 3, and the second blower 12 is arranged in this pipeline. There is.
  • the second blower 12 is a device that boosts the pressure of the second hydrocarbon-containing gas G1 and supplies it to the burner 3.
  • a desulfurizer and a gas filter are provided on the discharge side of the second blower 12, if necessary.
  • an oxidizing agent-containing gas G2 oxygen-containing gas such as air
  • the first air line L21 is a pipe line connecting the air intake port P20 and the low temperature side inlet of the air preheater 4, and the third blower 21 is arranged in this pipe line.
  • the third blower 21 is a device that boosts the pressure of the second oxidant-containing gas G2 and supplies it to the cathode 1b of the cell stack 1.
  • a gas filter is provided on the suction side of the third blower 21 as needed.
  • the second air line L22 is a pipeline connecting the low temperature side outlet of the air preheater 4 and the low temperature side inlet of the catalyst reactor 2.
  • the third air line L23 is a pipeline connecting the low temperature side outlet of the catalytic reactor 3 and the cathode side inlet of the cell stack 1.
  • the fourth air line L24 is a pipeline connecting the first air line L21 and the second air line L22 on the upstream side of the air preheater 4, and the first bypass valve 24 is arranged in this pipeline.
  • the first bypass valve 24 is a device for adjusting the temperature of the oxidizing agent-containing gas G2 (heating / cooling air) supplied to the catalyst reactor 2. For example, when the first bypass valve 24 is fully closed and all of the room temperature air sent from the third blower 21 is circulated to the air preheater 4, one of the combustion heat of the burner 3 is transferred to the partial oxidation catalyst described later. It can be heated by adding a portion.
  • first bypass valve 24 when the first bypass valve 24 is opened to bypass all or part of the room temperature air sent from the third blower 21 to the air preheater 4, a part of the reaction heat is recovered from the partial oxidation catalyst. Can be cooled.
  • a flow rate adjusting valve capable of proportionally controlling the valve opening degree is used.
  • the fifth air line L25 is a pipeline connecting the first air line L21 on the upstream side of the third blower 21 and the air supply port of the premixer 5, and the fourth blower 25 is arranged in this pipeline. Has been done.
  • the fourth blower 25 is a device that boosts the pressure of the first oxidant-containing gas G2 and supplies it to the premixer 5.
  • a gas filter is provided on the suction side of the fourth blower 25, if necessary.
  • the sixth air line L26 is a pipeline connecting the fourth air line L24 on the upstream side of the first bypass valve 24 and the cathode side inlet of the cell stack 1, and the second bypass valve 26 is contained in this pipeline. Have been placed.
  • the second bypass valve 26 is a device for adjusting the temperature of the oxidizing agent-containing gas G2 supplied to the cathode 1b of the cell stack 1. A part of the room temperature air sent from the third blower 21 is bypassed to the catalyst reactor 2 and the air preheater 4 and mixed with the high temperature air to adjust the air supply temperature below the serviceable temperature of the cell stack 1. ..
  • a flow rate adjusting valve capable of proportionally controlling the valve opening degree is used.
  • the sixth air line L26 and the second bypass valve 26 are not indispensable configurations, and are provided, for example, when the air supply temperature to the cathode 1b is too high even if the first bypass valve 24 is fully opened.
  • the premixed gas G3 flows through the premixed gas line L3.
  • the premixed gas line L31 is a pipeline connecting the gas discharge port of the premixer 5 and the high temperature side inlet of the catalytic reactor 2.
  • a hydrogen-containing gas G4 (reformed gas) is distributed in the reformed gas line L4.
  • the reformed gas line L4 is a pipeline connecting the high temperature side outlet of the catalytic reactor 2 and the anode side inlet of the cell stack 1.
  • the anode off-gas G5 flows through the first anode off-gas line L51 and the second anode off-gas line L52.
  • the "anode off gas” means a gas discharged from the anode 1a regardless of whether or not a power generation reaction is performed in the cell stack 1, and is a gas containing hydrogen and carbon monoxide.
  • the first anode off-gas line L51 is a pipeline connecting the anode-side outlet of the cell stack 1 and the fuel supply port of the burner 3.
  • the second anode off-gas line L52 is a pipeline branched from the middle of the first anode off-gas line L51 and connected to the off-gas supply port of the premixer 5, and the fifth blower 52 (52A) is in this pipeline. Is placed.
  • the fifth blower 52 sucks and pressurizes a part of the anode off gas G5 discharged from the cell stack 1 and mixes it with the hydrocarbon-containing gas G1 supplied to the catalyst reactor 2 for "anode off gas recycling". It is a device. That is, the second anode off-gas line L52 and the fifth blower 52 constitute a recycling means.
  • the cathode off gas G6 flows through the cathode off gas line L6.
  • the “cathode off gas” refers to a gas discharged from the cathode 1b regardless of whether or not a power generation reaction is performed in the cell stack 1, and is a gas containing oxygen.
  • the cathode off gas line L6 is a pipeline connecting the cathode side outlet of the cell stack 1 and the air supply port of the burner 3.
  • the combustion exhaust gas G7 circulates in the first exhaust gas line L71 and the second exhaust gas line L72.
  • the first exhaust gas line L71 is a pipeline connecting the combustion chamber outlet of the burner 3 and the high temperature side inlet of the air preheater 4.
  • the second exhaust gas line L72 is a pipeline connecting the high temperature side outlet of the air preheater 4 and the exhaust gas discharge port P30.
  • the gas flow rate may be adjusted by the blowers 11, 12, 21, 25, 52 by controlling the rotation speed of the drive motor, or the rotation speed of the drive motor may be fixed and a mass flow controller (mass flow meter, electromagnetic valve, etc.) may be used. It may be performed by a control device having a flow rate adjusting function).
  • the rotation speed control of the drive motor can be realized, for example, by controlling the brushless DC motor at a variable speed by pulse width modulation (PWM) or by controlling the AC motor by a variable voltage variable frequency control (VVVF control) by an inverter device.
  • PWM pulse width modulation
  • VVVF control variable voltage variable frequency control
  • the gas flow rate is adjusted by changing the duty ratio of the drive voltage pulse of the DC motor.
  • the gas flow rate is adjusted by changing the drive frequency or drive voltage of the AC motor.
  • a gas shutoff solenoid valve may be provided on the discharge side of each of the blowers 11, 12, 21, 25, 52.
  • the cell tack 1 is a power generator composed of a solid oxide fuel cell (SOFC).
  • SOFC solid oxide fuel cell
  • a solid oxide fuel cell is a high-temperature operating fuel cell in which the solid electrolyte, anode, and cathode that make up the power generation cell are all ceramics, and a predetermined number of power generation cells are made of a metal interconnector material (also called a separator material).
  • the power generation unit accumulated through the cell is called a cell stack. Note that FIG. 1 schematically shows only the anode 1a and the cathode 1b among the components of the cell tack 1.
  • the cell stack 1 is housed in a hot box whose inside becomes a high temperature atmosphere when the fuel cell system 100 is operated, and this hot box is covered with a heat insulating material and is thermally shielded from the outside. Further, the battery output of the cell stack 1 is supplied after being adjusted by the power conditioner 6 described later.
  • a flat plate type cell As the types of power generation cells, a flat plate type cell, a cylindrical horizontal stripe type cell, a cylindrical vertical stripe type cell, and a flat cylindrical type cell have been developed, and the flat plate type cell is further an anode-supported cell, a cathode-supported cell, and a metal-supported cell. It is classified into cells, electrolyte-supported cells, and insulator-supported cells.
  • the solid electrolyte is a film of ionic conductive ceramics that can permeate oxide ions, and ceramic materials such as yttria-stabilized zirconia (YSZ), scandia-stabilized zirconia (ScSZ), and lanthanum gallate (LaGaO 3 ) are used.
  • anode material metallic nickel (Ni) and yttria-stabilized zirconia (YSZ) cermets are used.
  • an electronic mixed conductor such as LSM, LSC, SSC, LSCF is used.
  • the reformed gas G4 (hydrogen, carbon monoxide-containing gas) produced from the hydrocarbon-containing gas G1 is supplied to the anode 1a of each power generation cell, and the oxidizing agent-containing gas G2 is supplied to the cathode 1b of each power generation cell.
  • the anode off-gas G5 discharged from the anode 1a during the power generation reaction contains unreacted hydrogen and carbon monoxide in addition to water vapor and carbon dioxide generated by the reaction.
  • the cathode off gas G6 discharged from the cathode 1b during the power generation reaction contains unreacted oxygen as well as nitrogen derived from air.
  • Cathode reaction O 2 + 4e- ⁇ 2O 2-
  • the anode material is a cermet of metallic nickel (Ni) and yttria-stabilized zirconia (YSZ), and the nickel in the anode changes to nickel oxide (NiO) when it comes into contact with oxygen in a high temperature state.
  • Ni metallic nickel
  • YSZ yttria-stabilized zirconia
  • NiO nickel oxide
  • the formation of nickel oxide not only reduces (in the worst case, loss) the activity of the anode in the power generation reaction and the reforming reaction, but also causes the volume expansion of the anode, which tends to cause damage to the power generation cell. Therefore, it is important to keep the anode in a reducing atmosphere when the temperature of the cell stack rises and falls.
  • the cell stack is heated or lowered while an inert gas such as nitrogen is circulated from a cylinder installed inside or outside the system to the anode, but in the present embodiment, the anode is used without using such means. It provides a means of maintaining a reducing atmosphere.
  • an inert gas such as nitrogen
  • the catalytic reactor 2 has a heat exchange core (described later), and a first hydrocarbon-containing gas G1 and / or an anode off-gas G5 is catalytically reacted with a first oxidizing agent-containing gas G2 inside the heat exchange core. It is a device that heats or cools the second oxidizing agent-containing gas G2 (cathode supply gas) by using the reaction heat to transfer heat.
  • the catalytic reactor 2 functions as a fuel reformer in which the first hydrocarbon-containing gas G1 is partially oxidized together with the second oxidant-containing gas G2 in the start-up operation and the shutdown operation of the system. .. Since the partial oxidation reaction is an exothermic reaction, the second oxidant-containing gas G2 to be heat-exchanged is heated. Further, the catalytic reactor 2 functions as a fuel reformer in which the hydrocarbon-containing gas G1 is subjected to a steam reforming reaction or a dry reforming reaction together with the anode off gas G5 in the power generation operation of the system. Since these reforming reactions are endothermic reactions, the second oxidant-containing gas G2 to be heat-exchanged is cooled. In the power generation operation, as will be described later, the oxidant-containing gas G2 may be supplied in addition to the hydrocarbon-containing gas G1 and the anode off-gas G5 to partially oxidize a part of methane.
  • the catalyst reactor 2 is configured as a two-fluid indirect heat exchanger in which a partial oxidation catalyst is applied to the heat transfer surface of the heat exchange core.
  • the catalyst reactor 2 is supplied with a first premixed gas G3 (a mixture of gases G1, G2, G5 according to the state of the system) from the premixed gas line L3, and second oxidation from the second air line L22.
  • the agent-containing gas G2 is supplied.
  • FIG. 2 is a schematic view when a shell-and-plate heat exchanger is applied to the catalytic reactor 2.
  • the detailed structure of the shell-and-plate heat exchanger is disclosed in, for example, Japanese Patent Application Laid-Open No. 2018-54215 by the present applicant.
  • the catalyst reactor 2 is arranged vertically in FIG. 2, it may be used in a horizontal arrangement.
  • a plate fin heat exchanger (a type in which both high-temperature fluid and low-temperature fluid flow in and out parallel to the plate surface) and a plate all-around junction type heat exchanger (high-temperature fluid and low-temperature fluid) A type) in which both the fluid flows in and out across the plate surface may be applied.
  • the catalytic reactor 2 includes a heat exchange core 21 made of a laminated body of heat transfer plates and a shell 22 accommodating the heat exchange core 21.
  • the heat exchange core 21 is configured by stacking a large number of plates, and closed and open flow paths for the internal space of the shell 22 are alternately formed between the plates.
  • the premixed gas G3 is introduced from the inlet pipe 211 penetrating the shell 22, becomes the reformed gas G4 while passing through the closed flow path group in the heat exchange core 21, and then from the outlet pipe 212 penetrating the shell 22. Derived.
  • the oxidant-containing gas G2 is introduced from the inlet pipe 221 communicating with the lower space of the shell 22, passes through the open flow path group in the heat exchange core 21, and then communicates with the upper space of the shell 21. Derived from.
  • a partial oxidation catalyst is applied to the heat transfer surface of the plate pair forming the closed flow path of the heat exchange core 21.
  • the heat exchange core 21 is manufactured by manufacturing a single plate coated with a partial oxidation catalyst in advance and joining the portions to be sealed while laminating the single plates.
  • the single plate is obtained by forming an alumina layer on one side surface of a stainless steel plate by whisker treatment, and then applying a slurry of a partial oxidation catalyst to sinter.
  • the heat transfer surface of the plate pair forming the open flow path of the heat exchange core 21 is not coated with the partial oxidation catalyst, and the base material of the plate is exposed.
  • the partial oxidation catalyst in addition to CeO 2 having an excellent oxygen storage function, Ni suitable for both partial oxidation and steam reforming can be used.
  • the catalytic partial oxidation (CPOX) of methane generated in the catalyst layer of the heat exchange core 21 is an exothermic reaction, and a reducing gas containing carbon monoxide and hydrogen is generated.
  • This reducing gas (POX gas) is used as an antioxidant gas for the anode 1a during the temperature raising operation and the temperature lowering operation of the cell stack 1, and is also used as the anode reaction gas when starting the power generation operation.
  • the supply flow rate of the oxidant-containing gas G2 may be adjusted so that the oxygen concentration has an air ratio ⁇ of less than 1. However, if the air ratio ⁇ is too low, carbon precipitation is likely to occur on the catalyst layer, so it is desirable to adjust the air ratio ⁇ to 0.3 or more.
  • the mixing of the oxidizing agent-containing gas G2 with the hydrocarbon-containing gas G1 is stopped, and the anode off-gas G5 (steam-containing gas) generated during the power generation of the cell stack 1 is mixed with the hydrocarbon-containing gas G1 (that is, the anode-off gas recycling).
  • the steam reforming reaction a dry reforming reaction occurs on the catalyst layer depending on the conditions.
  • a catalyst specialized for contact partial oxidation for example, CeO 2
  • these reforming reactions are relatively unlikely to occur, so that the reforming reaction on the anode becomes dominant.
  • the burner 3 is a single combustion device (combustion means) that integrates two functions. First, in order to obtain a heat source fluid (preheated air) for raising the temperature of the cold catalyst reactor 2 and the cell stack 1, the cathode off gas G6 is mixed with the high-calorie hydrocarbon-containing gas G1 for complete combustion. This is a function of supplying the high-temperature combustion exhaust gas G7 to the air preheater 4. Second, when the cell stack 1 is generating electricity, the low-calorie anode off-gas G5 (containing unreacted hydrogen and carbon monoxide) is mixed with the cathode-off gas G6 and completely combusted, resulting in one of flammable hydrogen and addiction.
  • a heat source fluid preheated air
  • the cathode off gas G6 is mixed with the high-calorie hydrocarbon-containing gas G1 for complete combustion. This is a function of supplying the high-temperature combustion exhaust gas G7 to the air preheater 4.
  • the low-calorie anode off-gas G5
  • the cathode off gas G6 discharged during the start-up operation and the shutdown operation of the system has almost the same oxygen concentration as the fresh oxidant-containing gas G2 taken in from the air inlet P20 (pre-power generation process SU4 and post-power generation process described later). Excluding SD1). Further, the cathode off gas G6 discharged to the power generation operation of the system is a gas having a lower oxygen concentration than the fresh oxidant-containing gas G2 taken in from the air intake port P20.
  • the burner 3 is preferably a diffusion combustion type (premixed type) burner structure.
  • a spark rod is used as the ignition device of the burner 3.
  • the burner 3 of the present embodiment is a device that burns a predetermined fuel with flame, but instead of this, a catalyst combustor capable of burning a predetermined fuel without flame may be mounted.
  • a catalyst combustor capable of burning a predetermined fuel without flame
  • the combustion catalyst for example, a precious metal such as Pt or Pd is used. Since the catalyst combustor uses a precious metal-based catalyst, it tends to be expensive, but it does not require a large combustion space as compared with the burner 3, so that it is easy to miniaturize. Further, for miniaturization and mass production, it is also preferable to configure the catalyst combustor in the same manner as the above-mentioned catalyst reactor 2.
  • the air preheater 4 is a device that preheats the room temperature oxidant-containing gas G2 supplied to the cathode 1b of the cell stack 1 by using the high-temperature combustion exhaust gas G7 discharged from the burner 3.
  • the air preheater 4 is configured as a two-fluid indirect heat exchanger (for example, a brazing plate heat exchanger), and an oxidizing agent-containing gas G2 is supplied as the first fluid from the first air line L21, and the first exhaust gas is discharged.
  • Combustion exhaust gas G7 is supplied as a second fluid from the line L71.
  • the premixer 5 is an apparatus for generating a premixed gas G3 in which an oxidant-containing gas G2 and an anode off gas G5 are mixed with a hydrocarbon-containing gas G1.
  • a premixer 5 for example, an in-line mixer having a built-in or attached stirring element can be used, but a simple structure such as a mixing pipe or a mixing box may be used.
  • the catalyst reactor 2, the burner 3, the air preheater 4, the premixer 5, and the fifth blower 52 (52A) are housed in the hot box together with the cell stack 1.
  • the first blower 11, the second blower 12, the third blower 21, the fourth blower 25, the first bypass valve 24, and the second bypass valve 26 are arranged outside the hot box.
  • the power conditioner 6 (PCS) is a device for converting the electric power generated by the cell stack 1 into a state that can be used in business activities and social life.
  • the power conditioner 6 converts the DC / DC converter (boost circuit) that boosts the DC voltage output from the cell stack 1 and the DC voltage boosted by the DC / DC converter into an AC voltage that is synchronized with the system power supply.
  • Grid interconnection inverter voltage conversion circuit
  • output current control unit output control circuit
  • drive power supply for supplying drive power to accessories. It has a part (auxiliary circuit).
  • the grid interconnection inverter is electrically connected to the switchboard of the commercial power supply system installed in the building.
  • the grid interconnection inverter and the switchboard can be switched between parallel and disconnection via a switch for grid interconnection.
  • a commercial power source and a plurality of distribution boards are electrically connected to the switchboard.
  • Load devices such as lighting fixtures, power units, and outlets used in the building are electrically connected to the distribution board.
  • the drive power supply unit is connected to the blowers 11, 12, 21, 25, 52, the first bypass valve 24, the second bypass valve 26, the spark rod of the burner 3, and the like, and supplies drive power to these auxiliary machines. ..
  • the drive power supply unit outputs, for example, the power obtained by AC / DC conversion of the output of the grid interconnection inverter, the power obtained by AC / DC conversion of the input from the commercial power supply, or the output of the cell stack 1.
  • the circuit is configured to supply DC / DC converted power.
  • the drive power supply unit is configured to supply, for example, the output power of the grid interconnection inverter or the input power from the commercial power supply.
  • the above-mentioned auxiliary equipment is driven by using a commercial power source during the start-up operation and the shutdown operation of the system, and is driven by using the generated power during the power generation operation of the system.
  • the system controller 7 is a device that controls the operation (that is, system operation) of auxiliary equipment such as a blower and the power conditioner 6 according to a control program created and stored in advance.
  • FIG. 3 (a) shows the relative time change of the gas flow rate by each blower 11, 12, 21, 25, 52, and the reference numeral written along with each line corresponds to the reference numeral of each blower.
  • FIG. 3B shows the relative time change between the internal temperature of the cell stack 1 and the catalyst temperature of the catalyst reactor 2, and the reference numerals shown on each line are the reference numerals of the cell stack 1 and the catalyst reactor 2. It corresponds to.
  • FIG. 3C shows the relative time changes of the sweep current Is of the cell stack 1, the fuel utilization rate Uf of the hydrocarbon-containing gas G1 during the current sweep, and the recycling rate Ra of the anode off-gas G5.
  • the cell stack 1 and the catalytic reactor 2 are in a cold state, the blowers 11, 12, 21, 25 and 52 are in a stopped state, and the first bypass valve 24 and the second bypass valve 26 are in a stopped state. It is in a closed state.
  • the premixer 5 the premixed gas line L3, the catalyst reactor 2 (flow path on the catalyst layer side), the reformed gas line L4, the anode 1a of the cell stack 1, the first anode off gas line L51 and the second anode off gas.
  • Oxidizing agent-containing gas G2 air is present in the recycling flow path including the line L52 by air purging (described later) executed at the initial stage of the cooling step SD3.
  • the startup operation is executed.
  • the start-up operation is executed so as to include the preheating step SU1, the POX starting step SU2, the heating step SU3, and the pre-power generation step SU4.
  • the preheating step SU1 is a state before the reaction operation of the catalyst reactor 2
  • the POX starting step SU2 to the temperature lowering step SD2 are states during the reaction operation of the catalyst reactor 2.
  • ⁇ Preheating process SU1> In this step, which is executed at the beginning of the start-up operation, the second blower 12 is first driven at the maximum flow rate, and the second hydrocarbon-containing gas G1 is supplied to the burner 3 through the second fuel line L12. Further, the third blower 21 is driven at the maximum flow rate, and the second oxidant-containing gas G2 is supplied to the burner 3 through the first air line L21 to the third air line L23 and the cathode off gas line L6. Then, when the spark rod is ignited, combustion of the burner 3 is started. The combustion exhaust gas G7 of the burner 3 is sent to the air preheater 4 through the first exhaust gas line L71, where the oxidant-containing gas G2 (cathode supply gas) is heated.
  • the oxidant-containing gas G2 heated by the air preheater 4 imparts a part of combustion heat to the catalyst layer through the heat transfer surface when passing through the catalyst reactor 2.
  • the oxidant-containing gas G2 cooled by the catalyst reactor 2 is further supplied to the cathode 1b to impart the balance of combustion heat and heat the entire cell stack 1.
  • the catalyst layer is preheated and the cell stack 1 is heated.
  • the temperature of the oxidizing agent-containing gas G2 supplied to the catalyst reactor 2 and the cathode 1b is adjusted by controlling the valve opening degree of the first bypass valve 24, and the internal temperature of the cell stack 1 is adjusted. Does not exceed the anode oxidation start temperature T1.
  • the gas flow rate of the second blower 12 may be gradually reduced as the catalyst temperature rises, and the combustion amount of the burner 3 may be adjusted.
  • the anode oxidation start temperature T1 means a predetermined temperature at which nickel in the anode comes into contact with oxygen and begins to change to nickel oxide (NiO) in the anode in a state of being exposed to a high temperature environment.
  • the system controller 7 shifts to the next “POX starting step SU2”.
  • the fifth blower 52 is first driven at the maximum flow rate to circulate the oxidant-containing gas G2 existing in the above-mentioned recycling flow path. After the recycling flow rate stabilizes, the gas flow rate of the second blower 12 is reduced toward zero or the minimum flow rate.
  • the first blower 11 is driven, and the first hydrocarbon-containing gas G1 is supplied to the premixer 5 through the first fuel line L11. Further, the fourth blower 25 is driven, and the first oxidant-containing gas G2 is supplied to the premixer 5 through the fifth air line L25.
  • the gas flow rate of the first blower 11 is gradually increased to an intermediate set flow rate lower than the maximum flow rate in synchronization with the operation of reducing the gas flow rate of the second blower 12.
  • the gas flow rate of the fourth blower 25 is gradually increased to the maximum flow rate in synchronization with the operation of reducing the gas flow rate of the second blower 12.
  • the contact partial oxidation reaction starts in the catalyst layer (the operation of the catalytic reactor 2 starts).
  • a reducing POX gas hydrogen-containing gas G4
  • this POX gas is supplied to the anode 1a.
  • the POX gas is discharged from the anode 1a as it is as the anode off-gas G5, and the fuel of the burner 3 is switched from the high-calorie hydrocarbon-containing gas G1 to the low-calorie anode-off gas G5.
  • the system controller 7 shifts to the next “heating step SU3”.
  • ⁇ Raising step SU3> In the third step of the start-up operation, the temperature of the cell stack 1 is continuously increased while maintaining the catalyst temperature of the catalyst reactor 2. Since the POX gas is circulated through the anode 1a at the time of executing this step, there is no problem even if the internal temperature of the cell stack 1 exceeds the anode oxidation start temperature T1, but the endurance temperature of the cell stack 1 is not exceeded.
  • the first bypass valve 24 is controlled to be fully open or close to fully open.
  • the serviceable temperature of a general SOFC cell stack is about 800 ° C., but the contact partial oxidation reaction is an exothermic reaction, and if the amount of oxidation reaction is excessive or the catalyst layer is completely insulated, the temperature of the POX gas is easy. It exceeds 1000 ° C. Therefore, in this step, by operating the fifth blower 52, the supply flow rate of the first hydrocarbon-containing gas G1 and the first oxidant-containing gas G2 to the catalyst reactor 2 is suppressed, and the temperature of the POX gas is lowered. I am trying.
  • anode off gas G5 By recycling the anode off gas G5 (POX gas), it is sufficient to supply an amount of methane and air that can supplement the discharged POX gas, so that the calorific value of the partial oxidation reaction is minimized. Further, inside the cell stack 1, a part of the heat held by the POX gas is transferred to the cathode air by heat exchange via the solid electrolyte, so that the cooled anode off gas G5 can be obtained. In addition to this, in this step, by supplying the oxidizing agent-containing gas G2 near room temperature, which bypasses the air preheater 4, to the low temperature side of the catalytic reactor 2, a part of the reaction heat accompanying the generation of POX gas is generated. It is recovered to further cool the POX gas.
  • the temperature of the POX gas supplied to the anode 1a and the temperature of the air supplied to the cathode 1b are balanced by heat exchange, and the POX gas is adjusted to an appropriate temperature range.
  • the reaction heat contained in the POX gas is fully used for raising the temperature of the cell stack 1, which contributes to shortening the temperature rising time.
  • the gas flow rates of the first blower 11 and the fourth blower 25 are adjusted so that the oxygen / carbon ratio (O / C) of the POX gas is within a predetermined range. Is desirable.
  • the system controller 7 shifts to the next “pre-power generation process SU4”.
  • a power generation standby process (hot standby process) is provided between the temperature raising process SU3 and the pre-power generation process SU4, and the pre-power generation process SU4 is executed after receiving an instruction to start power generation by a switch operation or the like. good.
  • the power generation standby step for example, while maintaining the cell stack 1 at the power generation possible temperature T3, the instruction to start power generation is awaited.
  • ⁇ Pre-power generation process SU4> In this step, which is executed at the end of the start-up operation, the gas flow rate of the first blower 11 is gradually increased from the intermediate set flow rate to the maximum flow rate (power generation reference flow rate). On the other hand, the gas flow rate of the fourth blower 25 is gradually reduced toward zero. As a result, the ratio of the amount of POX gas produced is reduced from 100% to 0%, while the ratio of the amount of reformed gas (gas obtained by the steam reforming reaction and the dry reforming reaction) is reduced from 0%. It will be raised to 100%. Further, in synchronization with the reduction of the amount of POX gas generated, the power conditioner 6 increases the ratio of the sweep current Is of the cell stack 1 from 0% (corresponding to the zero power generation current value) to 100% (corresponding to the rated current value). Pull up.
  • the ratio of the sweep current Is and the recycling rate Ra that is, the first
  • the oxygen / carbon ratio (O / C) of the hydrogen-containing gas G4 is within a predetermined range. 5 It is desirable to adjust the gas flow rate of the blower 52).
  • This step is a control state in which the generated power of the cell stack 1 is supplied to the load device by the grid interconnection of the power conditioner 6, and the ratio of the sweep current Is of the cell stack 1 is 100% (corresponding to the rated current value). ) And execute the "power generation operation of the system".
  • the gas flow rate of the first blower 11 is maintained at the power generation reference flow rate, and the fuel utilization rate Uf becomes the maximum (about 90%).
  • the hydrogen-containing gas G4 (reforming gas) required for power generation operation is obtained by a steam reforming reaction and a dry reforming reaction in the catalytic reactor 2 and / or the cell stack 1. The water vapor and carbon dioxide used in these reforming reactions will continue to be replenished by recycling the anode off-gas G5.
  • the recycling rate Ra (that is, the gas flow rate of the fifth blower 52) is set so that the oxygen / carbon ratio (O / C) of the hydrogen-containing gas G4 is within a predetermined range. ) Is desirable.
  • the preferred recycling rate is, for example, 60-80%.
  • the valve opening degree of the first bypass valve 24 is controlled in the vicinity of fully closed so that the internal temperature of the cell stack 1 does not fall below the appropriate power generation operating temperature T4, and the second bypass valve 24 is supplied to the cathode 1b. It is desirable to adjust the temperature of the oxidant-containing gas G2.
  • the operation may be performed so as to maintain the sweep current Is at a predetermined value (100% output), but the sweep current Is is adjusted according to the power consumption of the load device and within a predetermined range (for example,). It may be maintained at 50 to 100% output).
  • a predetermined range for example, in addition to controlling the valve opening degree of the first bypass valve 24, a required amount of the first oxidant-containing gas G2 is added according to the sweep current Is. It is desirable to supply to the catalytic reactor 2 through the air line L25.
  • the decrease in the internal temperature of the cell stack 1 due to the decrease in the amount of power generation reaction can be compensated for by the heat generation of the partial oxidation reaction, and the cell stack 1 can be maintained at the power generation operating temperature T4.
  • the supply amount of the first oxidant-containing gas G2 to the catalytic reactor 2 may be reduced to zero again.
  • the shutdown operation is executed.
  • the shutdown operation is performed so as to include the post power generation step SD1, the temperature lowering step SD2, and the cooling step SD3.
  • ⁇ Post power generation process SD1> In this step, which is executed at the beginning of the shutdown operation, the gas flow rate of the first blower 11 is gradually reduced from the maximum flow rate to the intermediate set flow rate. On the other hand, the fourth blower 25 is driven to gradually increase the gas flow rate toward the maximum flow rate. As a result, the ratio of the amount of POX gas produced is increased from 0% to 100%, while the ratio of the amount of reformed gas (gas obtained by the steam reforming reaction and the dry reforming reaction) is increased from 100%. It will be reduced to 0%. Further, in synchronization with the increase in the amount of POX gas produced, the power conditioner 6 increases the ratio of the sweep current Is of the cell stack 1 from 100% (corresponding to the rated current value) to 0% (corresponding to the zero power generation current value). reduce.
  • the ratio of the sweep current Is and the recycling rate Ra that is, the first
  • the oxygen / carbon ratio (O / C) of the hydrogen-containing gas G4 is within a predetermined range. 5 It is desirable to adjust the gas flow rate of the blower 52).
  • ⁇ Temperature lowering process SD2> the temperature lowering operation of the cell stack 1 is executed while maintaining the catalyst temperature of the catalyst reactor 2 at a temperature at which the contact partial oxidation reaction is possible.
  • the temperature lowering operation is executed, the POX gas is circulated through the anode 1a, while the valve opening degree of the first bypass valve 24 is gradually increased to fully open.
  • the temperature of the cell stack 1 is lowered. Then, this operation is continued until the internal temperature of the cell stack 1 reaches the air purgeable temperature T5, which is lower than the anode oxidation start temperature T1.
  • the supply flow rate of the first hydrocarbon-containing gas G1 and the first oxidant-containing gas G2 to the catalytic reactor 2 is suppressed, and the temperature of the POX gas is lowered. ing.
  • the anode off gas G5 POX gas
  • a part of the heat held by the POX gas is transferred to the cathode air by heat exchange via the solid electrolyte, so that the cooled anode off gas G5 can be obtained.
  • this step by supplying the oxidizing agent-containing gas G2 near room temperature, which bypasses the air preheater 4, to the low temperature side of the catalytic reactor 2, a part of the reaction heat accompanying the generation of POX gas is generated. It is recovered to further cool the POX gas. That is, the temperature of the POX gas supplied to the anode 1a and the temperature of the air supplied to the cathode 1b are balanced by heat exchange, and the POX gas is adjusted to an appropriate temperature range.
  • the temperature of the cell stack 1 proceeds efficiently. If it is desired to further shorten the temperature lowering time, the second bypass valve 26 may be controlled to be fully open to supply a lower temperature oxidizing agent-containing gas G2 to the cathode 1b.
  • the gas flow rates of the first blower 11 and the fourth blower 25 are adjusted so that the oxygen / carbon ratio (O / C) of the POX gas is within a predetermined range. Is desirable.
  • the system controller 7 shifts to the next “cooling step SD3”.
  • ⁇ Cooling process SD3> In this step, which is executed at the end of the shutdown operation, the first blower 11 and the third blower 21 are stopped. The reaction operation of the catalytic reactor 2 is stopped by cutting off the supply of the hydrocarbon-containing gas G1. On the other hand, the fourth blower 25 and the fifth blower 52 are driven at the maximum flow rate for a predetermined time (for example, 5 to 10 minutes) to execute air purging of the anode 1a and the recycling flow path. This air purge is an operation of replacing the flammable hydrogen and addictive carbon monoxide remaining inside the anode 1a of the catalyst reactor 2 and the cell stack 1 and the recycling flow path with the oxidant-containing gas G2 (air). ..
  • the fourth blower 25 and the fifth blower 52 are stopped.
  • the hot box is cooled to room temperature by leaving it in this state.
  • FIG. 4 is an explanatory diagram showing the configuration of the fuel cell system 200 according to the second embodiment.
  • the fuel cell system 200 additionally includes a first heat exchanger 8 and a second heat exchanger 9.
  • the same components as those in FIG. 1 are designated by the same reference numerals, and the description of the first embodiment will be referred to and detailed description thereof will be omitted.
  • the oxidizing agent-containing gas G2 (oxygen-containing gas such as air) flows through the first air line L21 to the seventh air line L27.
  • the first air line L21 is a pipe line connecting the air intake port P20 and the low temperature side inlet of the second heat exchanger 9, and a third blower 21 is arranged in this pipe line.
  • the seventh air line L27 is a pipeline connecting the low temperature side outlet of the second heat exchanger 9 and the low temperature side inlet of the air preheater 4.
  • the anode off-gas G5 flows through the first anode off-gas line L51 to the fifth anode off-gas line L55.
  • the first anode off-gas line L51 is a pipeline connecting the anode-side outlet of the cell stack 1 and the high-temperature side inlet of the first heat exchanger 8.
  • the second anode off-gas line L52 is a pipeline connecting the high temperature side outlet of the first heat exchanger 8 and the high temperature side inlet of the second heat exchanger 9.
  • the third anode off-gas line L53 is a pipeline connecting the high temperature side outlet of the second heat exchanger 9 and the fuel supply port of the burner 3.
  • the fourth anode off-gas line L54 is a pipeline that branches from the middle of the third anode off-gas line L53 and is connected to the low temperature side inlet of the first heat exchanger 8, and the fifth blower 52 (in this pipeline) 52B) is arranged.
  • the fifth anode off-gas line L55 is a pipeline connecting the low temperature side outlet of the first heat exchanger 8 and the off-gas supply port of the premixer 5.
  • the first heat exchanger 8 is configured as a self-reheating type heat exchanger, and the relatively low temperature anode off gas G5 recycled toward the premixer 5 is discharged from the cell stack 1 with the high temperature anode off gas G5. It is a device that reheats using. In other words, the first heat exchanger 8 is also a device that precools the high temperature anode off gas G5 discharged from the cell stack 1 using the relatively low temperature anode off gas G5 recycled toward the premixer 5. ..
  • the first heat exchanger 8 is configured as a two-fluid indirect heat exchanger (for example, a brazing plate heat exchanger).
  • the second heat exchanger 9 is a device that preheats the oxidant-containing gas G2 at room temperature supplied to the cathode 1b of the cell stack 1 using the relatively high-temperature anode off-gas G5 after passing through the first heat exchanger 8. Is.
  • the second heat exchanger 9 is configured as a two-fluid indirect heat exchanger (for example, a brazing plate heat exchanger).
  • the catalyst reactor 2, the burner 3, the air preheater 4, the premixer 5, the first heat exchanger 8 and the second heat exchanger 9 are housed in a hot box together with the cell stack 1.
  • the first blower 11, the second blower 12, the third blower 21, the fourth blower 25, the first bypass valve 24, and the second bypass valve 26 are arranged outside the hot box.
  • the fifth blower 52 (52B) is also arranged outside the hot box.
  • the fifth blower 52A in the first embodiment is arranged inside the hot box, a durable temperature of about 600 to 700 ° C. is required when the cell stack 1 operates for power generation.
  • the fifth blower 52B in the second embodiment is arranged outside the hot box, it suffices to have a withstand temperature of about 150 to 200 ° C. when handling the precooled anode off-gas G5.
  • the fifth blower 52B has a merit that it can be procured at a low cost because its serviceable temperature is sufficiently low, and it can be expected that the frequency of occurrence of defects can be suppressed.
  • the cost of procuring the fifth blower 52A in the first embodiment and the fifth blower 52B, the first heat exchanger 8 and the second heat exchanger 9 in the second embodiment It is desirable to compare the total procurement costs of and select the embodiment with the lowest procurement cost.
  • the operation control (operation control) of the fuel cell system 200 by the system controller 7 is the same as that of the first embodiment, and thus the description thereof will be omitted.
  • the fuel cell systems 100 and 200 of each embodiment include a cell stack 1 of a solid oxide fuel cell configured by integrating a plurality of power generation cells including a solid electrolyte, an anode 1a and a cathode 1b, and partial oxidation inside.
  • a power conditioner 6 for converting the generated power and a system controller 7 for controlling the system operation are provided.
  • No. 7 supplies the first hydrocarbon-containing gas G1 and the first oxidant-containing gas G2 to the catalytic reactor 2 to generate the hydrogen-containing gas G4, while producing the hydrogen-containing gas G4. It is configured to supply to the anode 1a and operate the recycling means during the reaction operation of the catalytic reactor.
  • the fuel cell systems 100 and 200 circulate the reducing POX gas generated by the partial oxidation reaction to the anode 1a to raise the temperature of the cell stack 1.
  • the temperature of the POX gas is lowered by operating the recycling means.
  • the POX gas is circulated through the anode 1a to lower the temperature of the cell stack 1.
  • the temperature of POX gas is lowered by operating the recycling means.
  • the fuel cell systems 100 and 200 are configured so as not to use a steam generating means (evaporator or the like) by heating with water. Since no steam generating means is used, no water sampling means (condenser, etc.) or water supply means (water tank, water pump, pure water device, etc.) is required.
  • a partial oxidation catalyst for fuel reforming and the addition of recycling means have made it possible to operate the system in a more rational process. As a result, the relatively high cost equipment required for conventional systems has been reduced. As a result, it is possible to provide a fuel cell system in which the initial cost can be suppressed and the system package can be easily miniaturized.
  • the fuel cell systems 100 and 200 of each embodiment have a single combustion means (burner) for burning the second hydrocarbon-containing gas G1 and / or the anode off gas G5 together with the cathode off gas G6 discharged from the cathode 1b. 3) and a gas preheater 4 for preheating the second oxidizing agent-containing gas G2 using the combustion exhaust gas G7 of this single combustion means.
  • a single combustion means for burning the second hydrocarbon-containing gas G1 and / or the anode off gas G5 together with the cathode off gas G6 discharged from the cathode 1b.
  • a gas preheater 4 for preheating the second oxidizing agent-containing gas G2 using the combustion exhaust gas G7 of this single combustion means.
  • the initial cost can be further suppressed. Further, by providing the gas preheater 4, the heat source fluid used for the start-up operation can be efficiently generated.
  • the catalyst reactor 2 in the fuel cell systems 100 and 200 of each embodiment is configured as a two-fluid indirect heat exchanger in which a partial oxidation catalyst is arranged in one flow path, and the system controller 7 is a system controller.
  • the gas preheater 4 is charged with the second oxidizing agent-containing gas G2 while the second hydrocarbon-containing gas G1 is burned by a single combustion means (burner 3). A part of the combustion heat is passed through the flow path on the side of the indirect heat exchanger where the partial oxidation catalyst is not arranged, and the second oxidant-containing gas G2 heated by the gas preheater 4 is circulated to the partial oxidation catalyst.
  • the second oxidant-containing gas G2 cooled by the indirect heat exchanger is supplied to the cathode 1b.
  • a part of the combustion heat of the burner 3 can be used to preheat the partial oxidation catalyst, and the rest of the combustion heat can be used to raise the temperature of the cell stack 1. Further, since this preheating / heating operation is indirect heating using the oxidizing agent-containing gas G2 (cathode air) as a heat medium, there is no possibility of causing the catalyst to burn out or the anode material to be oxidized.
  • G2 cathode air
  • the catalytic reactor 2 in the fuel cell systems 100 and 200 of each embodiment is configured as a two-fluid indirect heat exchanger in which a partial oxidation catalyst is arranged in one flow path, and the system controller 7 is a system controller.
  • the second oxidant-containing gas G2 is circulated through the flow path on the side where the partial oxidation catalyst of the indirect heat exchanger is not arranged to contain hydrogen.
  • a part of the reaction heat accompanying the generation of the gas G4 is recovered, the hydrogen-containing gas G4 cooled by the indirect heat exchanger is supplied to the anode 1a, and the second oxidizing agent-containing gas heated by the indirect heat exchanger is supplied.
  • G2 is supplied to the cathode 1b.
  • the POX gas is further cooled by circulating the oxidant-containing gas G2 before being supplied to the cathode 1b to the low temperature side of the catalyst reactor 2. While cooling the POX gas, the recovered reaction heat heats the oxidant-containing gas G2 (cathode air) to balance the gas temperatures supplied to the anode 1a and the cathode 1b. As a result, it is possible to shorten the temperature raising time and the temperature lowering time while avoiding overheating of the cell stack 1.
  • the second oxidant-containing gas G2 distributed to the indirect heat exchanger is a gas in which all or part of the gas preheater 7 is bypassed. ..
  • the system controller 7 of the fuel cell systems 100 and 200 of each embodiment is connected to the catalytic reactor 2 while operating the recycling means (second anode off-gas line L52 and fifth blower 52) in the power generation operation of the system.
  • the first hydrocarbon-containing gas G1 is supplied, and the required amount of the first oxidizing agent-containing gas G2 including zero is supplied to the catalytic reactor 2 according to the sweep current Is of the cell stack 1.
  • efficient power generation can be performed while increasing the fuel utilization rate Uf by recycling the anode off gas. Further, when the internal temperature of the cell stack 1 drops due to the partial load operation, the cell stack 1 can be maintained at the power generation operating temperature T4 by compensating for the amount of heat insufficient due to the heat generation of the partial oxidation reaction.
  • Fuel cell system 200 Fuel cell system 1 Cell stack 1a Anode 1b Cathode 2 Catalytic reactor 3 Burner 4 Air preheater (gas preheater) 5 Premixer 6 Power conditioner 7 System controller 8 1st heat exchanger 9 2nd heat exchanger 11 1st blower 12 2nd blower 21 3rd blower 24 1st bypass valve 25 4th blower 26 2nd bypass valve 52 5th blower (recycling means) L11 1st fuel line L12 2nd fuel line L21 1st air line L22 2nd air line L23 3rd air line L24 4th air line L25 5th air line L26 6th air line L27 7th air line L3 Premixed gas line L4 Modified gas line L51 1st anode off gas line L52 2nd anode off gas line (recycling means) L53 3rd anode off gas line L54 4th anode off gas line L55 5th anode off gas line L6 cathode off gas line L71 1st exhaust gas

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Abstract

La présente invention comprend un empilement de piles (1) de piles à combustible à oxyde solide, un réacteur catalytique (2) ayant un catalyseur d'oxydation partielle disposé à l'intérieur, un moyen de recyclage (52) qui peut fournir un gaz de dégagement d'anode (G5) au réacteur catalytique (2), un conditionneur de puissance (6), et un dispositif de commande de système (7). Dans l'opération de démarrage et d'arrêt du système, tout en fournissant un gaz contenant des hydrocarbures (G1) et un gaz contenant un agent oxydant (G2) au réacteur catalytique (2) et en générant un gaz contenant de l'hydrogène (G4), le dispositif de commande de système (7) fournit ce gaz contenant de l'hydrogène (G4) à une anode (1a), et pendant l'actionnement de la réaction du réacteur catalytique (2), actionne les moyens de recyclage (52).
PCT/JP2021/014395 2020-11-24 2021-04-02 Système de pile à combustible WO2022113397A1 (fr)

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JP2005174704A (ja) * 2003-12-10 2005-06-30 National Institute Of Advanced Industrial & Technology 燃料電池用改質装置、燃料電池、燃料電池の作動方法
JP2007311072A (ja) * 2006-05-16 2007-11-29 Acumentrics Corp 燃料電池システム及びその運転方法
JP2017073393A (ja) * 2012-02-10 2017-04-13 コンヴィオン オサケユキチュアＣｏｎｖｉｏｎ Ｏｙ 高温燃料電池システムのための再循環を利用する方法及び配置
JP2013254631A (ja) * 2012-06-06 2013-12-19 Denso Corp 燃料電池システム

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