JP2020161305A - Fuel cell system - Google Patents

Abstract

To provide a fuel cell system compatible of all operation modes, and capable of determining gas leakage with a convenient configuration without stopping operation.SOLUTION: A fuel cell system includes a fuel cell device X having an operation control section C for controlling operation of a solid oxide fuel cell 1, and a fuel level indicator Y having a measurement section Fb for measuring the total flow rate of fuel supplied to the solid oxide fuel cell 1 and other fuel consumption apparatuses 11, K via fuel supply passages L1, L6. The operation control section C is configured to be able to execute multiple operation modes, and regardless of execution of any operation mode, executes an abnormality determination operation mode for supplying a specified quantity of fuel to the solid oxide fuel cell 1 instead of the operation mode, and if a cumulative time when the total flow rate is within a prescribed range is less than a prescribed time during a prescribed period, a determination unit H determines that the fuel supply passages L1, L6 are abnormal.SELECTED DRAWING: Figure 1

Description

The present invention relates to a fuel cell system including a solid oxide fuel cell capable of supplying electric power generated by operation to a power load unit and supplying heat generated by operation to a heat load unit.

Conventionally, a fuel cell system having high power generation efficiency including a solid oxide fuel cell (SOFC) is known. In this fuel cell system, electricity generated by reacting hydrogen generated by reforming raw fuel in a reformer with air containing oxygen is supplied to a power load unit, and the heat generated by the reaction is supplied to hot water. It is supplied to the heat load section, which is used for applications and heating. Hot water heated by using the heat generated by the operation of the solid oxide fuel cell is supplied to this heat load unit. Further, in the fuel cell system, when the temperature of the hot water is lower than the temperature of the hot water required by the heat load section, the temperature of the hot water supplied to the heat load section by driving the combustion device becomes a desired temperature. It is controlled like this.

Commercial gas (for example, city gas 13A) is supplied to the reformer of these solid oxide fuel cells and gas appliances such as the combustion device and the gas stove, and the commercial gas is generally of gas. It is supplied via a gas leak detection device equipped with a protection function that detects leaks and performs alarms and gas shutoff operations. Conventionally, as a gas leak detection device, a gas meter with a microcomputer function provided in a gas supply pipe (hereinafter, referred to as “microcomputer meter”) has been used (see, for example, Patent Documents 1 to 3).

The microcomputer meter is equipped with various safety functions, one of which is "a function to issue an alarm when gas continues to flow for a predetermined time". This is a function aimed at detecting a gas leak when, for example, a rubber pipe or a gas pipe is damaged and a small amount of gas continues to leak, and the gas is continuously used for a certain period of time or longer (for example, 30 days). It is a function that detects a slight outflow of gas and issues an alarm.

When this alarm is issued, it is often necessary for the gas supply company to inspect it in order to cancel the alarm, and it is necessary to have no gas flow rate for a predetermined time (for example, 3 minutes or more) to cancel the alarm. Become. In addition to the burden on the user, this release work requires measures to temporarily stop the fuel cell system that continuously uses gas. Once the operation of the fuel cell system is stopped, it takes time to return to the state of steady operation. Especially in the case of solid oxide fuel cell, it takes about 10 hours for the stop stroke and about 2 to 3 hours for the restart stroke. It may be necessary. Therefore, the power load during that period cannot be supplemented by power generation, and the merit of introducing the fuel cell system cannot be fully utilized. Therefore, Patent Documents 1 to 3 disclose a control method for avoiding the generation of an alarm by the microcomputer meter and suppressing a decrease in the operational efficiency of the fuel cell system without disabling the protection function of the microcomputer meter. There is.

The fuel cell system described in Patent Document 1 is a technique in which a plurality of candidate dates for stopping the operation of the fuel cell system are provided, calculations are performed from patterns of electric power demand and hot water supply demand stored in advance, and an optimum stop date is selected. However, if the operation stop period is set long, the merit of introducing the fuel cell system is diminished, and if the operation stop period is set short, there is a risk that gas leakage may be erroneously determined due to the operation of gas appliances such as a gas stove.

On the other hand, the fuel cell system described in Patent Document 2 is provided with a seasonal determination means for shortening the power generation suspension period, and shortens the power generation suspension period in the summer when the usage rate of gas appliances is low. This prevents erroneous determination of gas leaks and reduces the loss of merit of introducing a fuel cell system.

Further, when the fuel cell system described in Patent Document 3 is in the vicinity of the fixed flow rate range of the ignition registration function during the execution of the load following operation mode in which the fuel cell system operates at a gas flow rate that follows the power load, Continuous operation is performed in the fixed flow rate operation mode. As a result, if the cumulative time of continuous operation in the fixed flow rate operation mode is equal to or longer than the reference time, it is not determined to be a gas leak.

Japanese Unexamined Patent Publication No. 2005-353292 Japanese Unexamined Patent Publication No. 2016-223690 Japanese Unexamined Patent Publication No. 2012-209137

In the fuel cell system described in Patent Documents 1 and 2, it is necessary to temporarily stop the operation of the fuel cell system, and therefore, in particular, a solid oxide fuel cell that takes time to return to a steady operation state. In this case, the merit of introducing the fuel cell system diminishes, and there is room for improvement. Further, in the fuel cell system described in Patent Document 3, when the gas flow rate fluctuates near the fixed flow rate range during the execution of the load following operation mode, the fuel cell system is operated at a fixed flow rate, and the gas flow rate does not fluctuate. It cannot support the rated output operation mode. Further, in the fuel cell system described in Patent Document 3, not only the control for shifting from the load following operation mode to the fixed flow rate operation mode is complicated, but also the load following operation mode and the fixed flow rate operation mode are frequently performed. There is a risk of switching to, and management of operating time is complicated.

Therefore, there is a demand for a fuel cell system that can support all operation modes and can determine gas leakage with a simple configuration without stopping the operation.

The characteristic configuration of the fuel cell system according to the present invention is a solid oxide fuel cell capable of supplying the electric power generated by the operation to the electric power load unit and the heat generated by the operation to the heat load unit, and the solid oxide. A fuel cell device having an operation control unit for controlling the operation of the fuel cell, and the total flow rate of fuel supplied to the solid oxide fuel cell and other fuel consuming devices via the fuel supply path are measured. The operation control unit includes a measurement unit, a fuel meter having a determination unit for determining the presence or absence of an abnormality in the fuel supply path based on the total flow rate measured by the measurement unit, and the operation control unit. The mode is configured to be executable, and an abnormality determination operation mode in which a predetermined amount of fuel is supplied to the solid oxide fuel cell in place of the operation mode regardless of which operation mode is being executed. When the cumulative time in which the total flow rate is within the predetermined range is equal to or longer than the predetermined time during the predetermined period, the determination unit resets the cumulative time, and the cumulative time reaches the predetermined time during the predetermined period. When it is less than the time, it is determined that the fuel supply path is abnormal.

In this configuration, the abnormality determination operation mode for supplying a predetermined amount of fuel to the solid oxide fuel cell is executed regardless of which operation mode the operation control unit is executing. Since this abnormality determination operation mode supplies a predetermined amount of fuel to the solid oxide fuel cell, the total flow rate of fuel measured by the fuel gauge is within a predetermined range unless fuel is used in other fuel consuming equipment. Be inside. Then, when the cumulative time during which the total flow rate is within the predetermined range is equal to or longer than the predetermined time, the determination unit determines that the fuel supply path is normal and resets the cumulative time (prevents false detection). .. On the other hand, when a gas leak occurs from the fuel supply path, the total flow rate of the fuel measured by the fuel gauge in the abnormality determination operation mode is out of the predetermined range. Then, when the cumulative time in which the total flow rate is within the predetermined range is less than the predetermined time during the predetermined period, the determination unit determines that the fuel supply path is abnormal.

That is, it is possible to detect a gas leak from the fuel supply path by forcibly executing the abnormality determination operation mode while the power generation is being continued by the normal operation of the fuel cell device. Further, since it is a condition that the cumulative time during which the total flow rate is within the predetermined range is equal to or longer than the predetermined time during the predetermined period, gas leakage from the fuel supply path can be reliably detected. Therefore, it has been possible to provide a fuel cell system that can support all operation modes and can determine gas leakage with a simple configuration without stopping the operation of the fuel cell device.

Another characteristic configuration is that the operation control unit executes the abnormality determination operation mode by combining a plurality of flow patterns having different fuel flow rates as the predetermined amount.

If the abnormality determination operation mode is executed by combining a plurality of flow patterns having different fuel flow rates as in this configuration, the probability that the flow rate of the fuel supplied to the solid oxide fuel cell will be within the predetermined range will increase. It is possible to absorb fluctuation errors due to the temperature of the total flow rate of fuel measured by the fuel gauge. Therefore, gas leakage from the fuel supply path can be detected more reliably.

Another feature configuration is that the operation control unit executes the abnormality determination operation mode based on the set operation time.

In this configuration, it is possible to execute various abnormality determination operation modes such as 6 hours every 10 days and 10 minutes every day, and the optimum operation can be performed according to the usage pattern of the fuel cell device at the introduction destination. Therefore, efficient operation of the fuel cell device can be realized.

Another characteristic configuration further includes a communication mechanism for communicating between the operation control unit and the determination unit, and the operation control unit acquires a determination result by the determination unit via the communication mechanism and performs the operation. The control unit releases the abnormality determination operation mode when the cumulative time is equal to or longer than the predetermined time during the predetermined period.

If the abnormality determination operation mode of the fuel cell device is canceled when the condition that the cumulative time during which the total flow rate is within the predetermined range is equal to or longer than the predetermined time is satisfied as in this configuration, the next time from the release time. Normal operation is possible until the judgment, and efficient operation of the fuel cell device can be realized.

Another feature configuration is that the determination unit detects the abnormality determination operation mode via the communication mechanism.

In this configuration, the abnormality determination operation mode can be detected in real time. As a result, the fuel gauge can more reliably detect a gas leak from the fuel supply path by operating the determination unit when the fuel cell device is in the abnormality determination operation mode.

It is an overall block diagram of a fuel cell system. It is a control flow diagram. It is a figure which shows an example of an abnormality determination operation mode. It is a figure which shows an example of an abnormality determination operation mode.

Hereinafter, embodiments of the fuel cell system according to the present invention will be described with reference to the drawings. In the present embodiment, as an example of the fuel cell system, a fuel cell system including a fuel cell device X having a solid oxide fuel cell 1 (SOFC) will be described. However, the present invention is not limited to the following embodiments, and various modifications can be made without departing from the gist thereof.

FIG. 1 is a diagram showing a configuration of a fuel cell system including a fuel cell device X. The fuel cell system includes a fuel cell device X and a fuel gauge Y.

[Fuel cell device X]
The fuel cell device X supplies the solid oxide fuel cell 1 and the solid oxide fuel cell 1 that supply the electric power generated by the operation to the electric power load unit 3 and the heat generated by the operation to the heat load unit 4. It includes an operation control device C (an example of an operation control unit) that controls the operation of the fuel cell device X including the fuel cell device X, and an outside air temperature sensor T1 that measures the outside air temperature. The electric power load unit 3 can consume the electric power supplied from the commercial power source 15 in addition to the electric power supplied from the solid oxide fuel cell 1. Further, the heat load unit 4 can also consume the heat supplied from the auxiliary heat source device 11 that burns the raw fuel to generate heat, in addition to the heat generated from the solid oxide fuel cell 1. The operation control device C is composed of hardware and software having an information processing function, an information storage function, an information communication function (an example of a communication mechanism), and the like.

In the solid oxide fuel cell 1, the vaporizer 1b that evaporates the supplied reforming water and the raw material fuel (gas containing hydrocarbons, for example, city gas 13A) are steam reformed and the fuel gas (gas containing hydrogen) is reformed. ), A cell stack having a plurality of fuel cell cells S that generate power using the fuel gas generated by the reformer 1a, and a combustion unit 1c that burns off gas from the cell stack. Is provided inside the container 1A. The container 1A is preferably constructed using a material having heat insulating properties. The cell stack is electrically connected to the inverter 12.

The cell stack has an anode 50 having a fuel passage (not shown) through which the fuel gas generated by the reformer 1a passes, and an air passage (not shown) through which oxygen (air) passes. A plurality of fuel cell S including the cathode 60 having the above are electrically connected in series. Although not shown, the fuel cell S is composed of a solid oxide fuel cell having a solid electrolyte layer between the anode 50 and the cathode 60. The fuel gas is supplied to the anode 50 by passing the fuel gas through the fuel passage portion, and oxygen is supplied to the cathode 60 by passing the air through the air passage portion. The cell stack is installed inside the container 1A in a state in which a plurality of fuel cell S are arranged side by side with the fuel gas discharge port 50a of the fuel passage portion and the air discharge port 60a of the air passage portion facing upward. Has been done.

A gas manifold 1e that receives the fuel gas supplied from the reformer 1a through the fuel gas flow path L4 is provided in the lower part of the cell stack. The plurality of fuel cell S are arranged on the upper side of the gas manifold 1e in a state of being arranged as described above, and the gas inlets at the lower ends of the fuel flow portions in the gas manifold 1e and the plurality of fuel cell S (not shown). ) Is connected in communication. Then, the fuel gas supplied to the gas manifold 1e is supplied from the gas introduction port at the lower end to each fuel passage portion of the plurality of fuel cell S, and the fuel gas is downward to each fuel passage portion. It flows from the side to the upper side and is used for the power generation reaction. The discharged fuel gas after being subjected to the power generation reaction is discharged from the fuel gas discharge port 50a at the upper end.

The solid oxide fuel cell 1 is provided with an air introduction unit 70, and an air supply flow path L5 is connected to the air introduction unit 70. An air filter 21, an air blower 22, and an air flow meter 23 are provided in the middle of the air supply flow path L5. By the operation of the air blower 22, air is supplied into the container 1A through the air supply flow path L5. The air filter 21 catches foreign matter such as dust in the air sucked into the air supply flow path L5 by the air blower 22. The air flow meter 23 measures the flow rate of air supplied into the container 1A per unit time. An air supply hole (not shown) that communicates the inside of the container 1A and the inside of the air passage portion is provided in the vicinity of the lower end portion of the air passage portion in each of the plurality of fuel cell S. The air in the container 1A is supplied to each of the air passages of the plurality of fuel cell S through the air supply holes, and the air flows from the lower side to the upper side to each air passage to generate electricity. Subject to reaction. The exhaust air after being subjected to the power generation reaction is discharged from the air discharge port 60a at the upper end. The measurement result of the air flow meter 23 is transmitted to the operation control device C, and the operation of the air blower 22 is controlled by the operation control device C.

Above the cell stack, a combustion space is formed for burning the discharged fuel gas containing hydrogen that was not used in the power generation reaction discharged from the fuel gas discharge port 50a and the exhaust air discharged from the air discharge port 60a. Will be done. These discharged fuel gas and exhaust air become off-gas from the cell stack. An igniter 1d is also provided in this combustion space. That is, the combustion space 1c above the cell stack realizes the combustion unit 1c that burns the off-gas from the cell stack. In addition, an integrally configured carburetor 1b and reformer 1a are provided adjacent to the combustion space above the cell stack that functions as the combustion unit 1c. The operation of the igniter 1d is controlled by the operation control device C. The combustion temperature sensor T4 measures the temperature of the combustion unit 1c, and the measurement result is transmitted to the operation control device C. Then, it is used for determining whether or not the combustion in the combustion unit 1c is properly performed.

In the container 1A, an exhaust unit 80 for exhausting the combustion exhaust gas generated in the combustion unit 1c to the outside via the heat exchanger E is formed at the lower portion. A combustion catalyst unit 90 (for example, a platinum-based catalyst) for removing carbon monoxide gas or the like in the combustion exhaust gas discharged to the outside from the exhaust unit 80 is provided in the container 1A. The atmospheric temperature sensor T5 measures the temperature inside the container 1A, for example, the temperature on the side of the cell stack, and the measurement result is transmitted to the operation control device C.

The vaporizer 1b heats and evaporates the supplied reforming water using the combustion heat transmitted from the combustion unit 1c. The reforming water stored in the reforming water tank 24 is supplied to the vaporizer 1b via the reforming water flow path L2 connected to the reforming water tank 24. Specifically, when the reforming water pump P operates, the reforming water stored in the reforming water tank 24 flows through the reforming water flow path L2 and flows into the inside of the vaporizer 1b. The operation of the reforming water pump P is controlled by the operation control device C. In this way, the reforming water pump P functions as a water flow rate adjusting unit that adjusts the flow rate of reforming water supplied to the reformer 1a per unit time.

Raw fuel is also supplied to the vaporizer 1b via the raw material / fuel flow path L1. A mass flow meter Fa and a raw fuel blower B are provided in the middle of the raw material flow path L1. As the mass flow meter Fa, for example, a thermal mass flow meter that measures by utilizing the thermal diffusion action of raw materials and fuel is used. Further, the raw fuel flow path L1 on the downstream side of the raw fuel blower B is provided with a desulfurizer 20 for removing sulfur compounds contained in the raw fuel (for example, city gas). Then, when the raw material blower B operates, the raw material flows through the raw material fuel flow path L1 and is desulfurized by the desulfurizer 20, and then flows into the inside of the vaporizer 1b. The mass flow meter Fa measures the flow rate of the raw material and fuel supplied to the carburetor 1b per unit time, and the measurement result is transmitted to the operation control device C. When the mass flow meter Fa is a thermal mass flow meter, the operation control device C determines the flow rate of the raw fuel with reference to the stored value of the heat supply raw material and fuel. The operation control device C controls the operation of the raw fuel blower B and the on-off valve V1 described later so that the flow rate of the raw fuel measured by using the mass flow meter Fa becomes a target flow rate. In this way, the raw material fuel blower B and the on-off valve V1 function as a raw material fuel flow rate adjusting unit that adjusts the flow rate of the raw material supplied to the reformer 1a per unit time. As described above, in the vaporizer 1b, a mixed gas in which the raw fuel and steam whose supply amount per unit time is controlled by the operation control device C is mixed is generated, and reformed through the mixed gas flow path L3. It is supplied to the vessel 1a.

The reformer 1a performs steam reforming treatment of the raw material and fuel contained in the mixed gas supplied from the vaporizer 1b. Although not shown, the reformer 1a is filled with a reforming catalyst, and the raw fuel is reformed by the catalytic action of the reforming catalyst. Further, like the vaporizer 1b, the combustion heat generated in the combustion unit 1c is also transmitted to the reformer 1a. The reforming temperature sensor T3 measures the temperature of the reformer 1a (for example, the temperature of the reforming catalyst), and the measurement result is transmitted to the operation control device C. Then, it is used for determining whether or not the temperature of the reformer 1a is appropriate.

[Power supply to power load unit 3]
The generated power of the solid oxide fuel cell 1 is supplied to the inverter 12. The inverter 12 sets the generated power of the solid oxide fuel cell 1 to the same voltage and frequency as the received power received from the commercial power source 15. The operation of the inverter 12 is controlled by the operation control device C. The inverter 12 is electrically connected to the received power supply line 14 via the generated power supply line 13. Then, the generated power from the solid oxide fuel cell 1 is supplied to the power load unit 3 via the inverter 12, the generated power supply line 13, and the received power supply line 14. The received power supply line 14 is connected to the commercial power source 15. That is, power is supplied to the power load unit 3 from at least one of the solid oxide fuel cell 1 and the commercial power source 15.

The received power supply line 14 is provided with a power load measuring unit 16 for measuring the power load of the power load unit 3, and the measurement result is transmitted to the operation control device C. Then, the operation control device C is controlled so that the generated power supplied from the solid oxide fuel cell 1 to the received power supply line 14 by the inverter 12 becomes equal to the power load detected by the power load measuring unit 16. (Load follow-up operation mode). Further, the operation control device C can also operate the solid oxide fuel cell 1 at the rated output (the gas flow rate supplied to the solid oxide fuel cell 1 is 120 to 130 L / h) (rated output). Operation mode). Further, the operation control device C can also operate the solid oxide fuel cell 1 in an idling state (the gas flow rate supplied to the solid oxide fuel cell 1 is 50 L / h or less) (idling operation mode). ). However, in the load following operation mode, the power load measured by the power load measuring unit 16 is from the minimum generated power of the solid oxide fuel cell 1 (the minimum generated power supplied to the received power supply line 14 by the inverter 12). If is also small, surplus power is generated. Further, in the rated output operation mode, when the solid oxide fuel cell 1 is operated at the rated output and the output power from the inverter 12 is larger than the power load, surplus power is generated. If reverse power flow to the commercial power source 15 is possible, the surplus power may be supplied to the commercial power source 15. When the reverse power flow of the electric power to the commercial power source 15 is not recognized, the surplus electric power may be consumed by the electric heater 9 for consuming the surplus electric power which is recovered instead of the heat.

The electric heater 9 is composed of a plurality of resistance heaters, and heats hot water flowing through the exhaust heat recovery path 6 by operating the exhaust heat recovery pump 7. ON / OFF of the electric heater 9 is switched by the operation switch 10 connected to the output side of the inverter 12. Further, the operation switch 10 is switched so that the power consumption of the electric heater 9 increases as the magnitude of the surplus power of the solid oxide fuel cell 1 increases. The operation of the operation switch 10 is controlled by the operation control device C.

It should be noted that what kind of device is included in the power load unit 3 can be appropriately set. For example, an auxiliary machine used for operating the solid oxide fuel cell 1 and an antifreezing heater for preventing freezing of hot water supplied to the heat load unit 4 are excluded from the power load unit 3. Is also possible. Further, the standby power of the power load unit 3 may be subtracted from the power load measured by the power load measurement unit 16.

[Supplying heat to the heat load unit 4]
The heat generated by the solid oxide fuel cell 1 is stored in the hot water storage tank 2 in the form of hot water. That is, the hot water storage tank 2 stores hot water heated by using the heat generated by the operation of the solid oxide fuel cell 1. Clean water is supplied to the lower part of the hot water storage tank 2 via the water supply channel 17. The water supply channel 17 is provided with a water supply temperature sensor T2 for measuring the water supply temperature. Hot water is stored in the hot water storage tank 2 in the present embodiment in a state of forming a temperature stratification. That is, inside the hot water storage tank 2, relatively low temperature hot water is stored in the lower part thereof, and relatively high temperature hot water is stored in the upper part thereof. The hot water stored in the hot water storage tank 2 circulates between the heat exchanger E and the hot water storage tank 2 through which the combustion exhaust gas of the solid oxide fuel cell 1 flows through the exhaust heat recovery path 6. The flow of hot water in the exhaust heat recovery path 6 is performed by the exhaust heat recovery pump 7. The operation of the exhaust heat recovery pump 7 is controlled by the operation control device C. For example, when the operation control device C needs to start the operation of the solid oxide fuel cell 1 and recover the heat discharged from the solid oxide fuel cell 1, the exhaust heat recovery pump 7 is used. By operating the hot water, the relatively low temperature hot water stored in the lower part of the hot water storage tank 2 is flowed to the exhaust heat recovery path 6. Then, the relatively low temperature hot water flowing through the exhaust heat recovery path 6 recovers the heat discharged from the solid oxide fuel cell 1 (the hot water is heated by the exhaust heat of the solid oxide fuel cell 1). , It becomes relatively hot water and flows into the upper part of the hot water storage tank 2.

In the middle of the exhaust heat recovery path 6, a radiator 8 for dissipating heat from hot water flowing from the hot water storage tank 2 to the heat exchanger E through the exhaust heat recovery path 6 is installed. When the temperature of the hot water flowing from the hot water storage tank 2 to the heat exchanger E is less than the set upper limit temperature, the operation control device C stops the operation of the radiator 8. On the other hand, when the temperature of the hot water flowing from the hot water storage tank 2 to the heat exchanger E is equal to or higher than the set upper limit temperature, the operation control device C causes the radiator 8 to dissipate heat to lower the temperature of the hot water. Further, the Joule heat generated by energizing the electric heater 9 is configured to be recovered by hot water flowing from the heat exchanger E to the hot water storage tank 2 in the middle of the exhaust heat recovery path 6.

The relatively high temperature hot water stored in the upper part of the hot water storage tank 2 is supplied to the heat load unit 4 via the hot water supply path 5 and the auxiliary heat source device 11 connected to the upper part of the hot water storage tank 2.

The heat load unit 4 is used for hot water supply, heating, and the like. When the heat load unit 4 is used for hot water supply, the hot water does not return to the hot water storage tank 2. When the heat load unit 4 is used for heating, only the heat possessed by the hot water is consumed, and the hot water may return to the hot water storage tank 2. The hot water supply path 5 is provided with an auxiliary heat source device 11 for heating the hot water flowing through the hot water supply path 5. When the temperature of the hot water flowing out from the upper part of the hot water storage tank 2 is lower than the temperature of the hot water required by the heat load unit 4, the operation control device C operates the auxiliary heat source device 11 to supply the hot water to the heat load unit 4. Control is performed so that the temperature of the hot water to be produced becomes a desired temperature. The operation control device C controls the operation of the auxiliary heat source device 11.

[Fuel gauge Y]
The fuel meter Y is composed of a raw material (fuel) supplied to the solid oxide fuel cell 1 via a raw material fuel flow path L1 (an example of a fuel supply path), an auxiliary heat source device 11, a gas controller K, and the like. Total volume of raw material (fuel) supplied to other fuel consuming equipment via the raw material flow path L6 (example of fuel supply path) (example of total flow rate, solid oxide fuel cell 1 and other fuels) It is provided with a volume flow meter Fb (an example of a measuring unit) that measures the total value of the volume flow rate of raw materials and fuel consumed by the consumer equipment, hereinafter simply referred to as "total volume"). This volumetric flow meter Fb is composed of a microcomputer meter having a safety function including at least "a function of issuing an alarm when gas continues to flow for a predetermined time". As one of the safety functions, an alarm is issued when the cumulative time for a flow rate (total volume) of a very small amount or less has not reached a predetermined time (for example, 1 hour) during a predetermined period (for example, 30 days). , It has a function to reset the cumulative time (make the cumulative time zero) when the predetermined time is reached. In addition, as one of the safety functions, during a predetermined period (for example, 30 days), a predetermined range (for example, ± 10) is provided with respect to a set flow rate (for example, 30 L / h) set within a range in which a fire can be registered. An alarm is issued when the cumulative time for the flow rate (total volume) at (%) has not reached the predetermined time (for example, 1 hour), and the cumulative time is reset when the predetermined time is reached (cumulative time is zero). It has a function.

The fuel gauge Y includes an abnormality determination unit H (an example of the determination unit) for determining the presence or absence of an abnormality in the raw material / fuel flow paths L1 and L6 based on the total volume of the raw material and fuel measured by the volume flow meter Fb. The volume flow meter Fb is a membrane gas meter that measures the amount of raw fuel used (total volume) from the number of operations of the movable membrane that separates the two measuring chambers, or a membrane gas meter that measures the gas flow velocity with an ultrasonic sensor. It consists of an ultrasonic gas meter that measures the amount of fuel used (total volume). When the volume flow meter Fb is composed of an ultrasonic gas meter, the device can be miniaturized and the amount of raw materials and fuel used can be measured instantly.

The raw fuel flow path L1 for supplying raw fuel to the solid oxide fuel cell 1 is provided with an electromagnetic opening / closing valve V1 capable of blocking the flow of raw fuel between the fuel gauge Y and the mass flow meter Fa. ing. The raw fuel flow path L6 for supplying raw fuel to the auxiliary heat source device 11 is provided with an electromagnetic valve V2 capable of adjusting the supply amount of raw fuel. Solenoid valves V3 capable of adjusting the supply amount of the raw fuel are provided in each of the raw material flow paths L6 for supplying the raw fuel to a plurality of fuel consuming devices composed of the gas stove K and the like.

[Driving mode]
As described above, the operation control device C is configured to be capable of executing a plurality of operation modes (load follow-up operation mode, rated output operation mode, idling operation mode, etc.). The operation control device C in the present embodiment is connected to the solid oxide fuel cell 1 via the raw material / fuel flow path L1 instead of the executing operation mode regardless of which operation mode is being executed. An abnormality determination operation mode for supplying a predetermined amount (for example, 45 L / h) of raw fuel is forcibly executed (see FIG. 3). That is, the operation control device C controls the operation of the raw material fuel blower B and the like so that the amount of raw material flowing through the raw material fuel flow path L1 becomes a predetermined amount instead of any operation mode. In setting this predetermined amount, the user or the gas supplier may arbitrarily set the amount within the range that can be registered as a starter (50 L / h or less), or the solid oxide fuel cell 1 may be set. It may be set by artificial intelligence machine-learned based on the driving performance.

Further, the operation control device C executes the abnormality determination operation mode based on the set operation time (for example, every 10 days for 6 hours continuously, or every day for 20 minutes, etc.). The operation time may be set arbitrarily by the user or the gas supply company, or may be set by machine-learned artificial intelligence based on the operation results of the solid oxide fuel cell 1. Is also good.

In the abnormality determination unit H of the fuel gauge Y, the cumulative time during which the total volume of the raw fuel measured by the volume flow meter Fb is within a predetermined range (for example, 45 L / h ± 5%) is during a predetermined period (for example, 30 days). When the predetermined condition of the predetermined time (for example, 1 hour) or more is not satisfied, it is determined that a gas leak has occurred (abnormal) from the raw material / fuel flow paths L1 and L6, and a gas leak alarm is issued. .. Further, in the abnormality determination unit H, the cumulative time during which the total volume of the raw materials and fuels measured by the volume flow meter Fb is within a predetermined range (for example, 45 L / h ± 5%) is a predetermined time during a predetermined period (for example, 30 days). When the predetermined condition of (for example, 1 hour) or more is satisfied, it is determined that no gas leak has occurred from the raw material / fuel flow paths L1 and L6 (normal), and the cumulative time is reset to the next time. The execution of the abnormality determination operation mode is stopped until the predetermined period is reached.

FIG. 2 shows an example of a control mode of the operation control device C and the fuel gauge Y. First, the operation control device C controls the solid oxide fuel cell 1 in any of a plurality of operation modes (load follow-up operation mode, rated output operation mode, idling mode, etc.) (# 21). Then, the operation control device C determines whether or not to execute the abnormality determination operation mode based on the operation time set by the solid oxide fuel cell 1 (# 22).

When it is determined as a result of the determination of # 22 that the mode shifts from any operation mode to the abnormality determination operation mode (# 22Yes), the operation control device C connects the solid oxide fuel cell 1 to the solid oxide fuel cell 1 via the raw fuel flow path L1. The abnormality determination operation mode for supplying a predetermined amount (45 L / h) of raw material and fuel is forcibly executed (# 23). Then, the flow rate of the raw fuel supplied to the raw material flow path L1 is measured by the mass flow meter Fa, and the operation control device C uses the raw fuel blower B or the like so that the measured value of the mass flow meter Fa becomes the target flow rate. Controls the operation of (# 24).

Next, the volume flow meter Fb of the fuel gauge Y is composed of the raw fuel supplied to the solid oxide fuel cell 1 via the raw fuel flow path L1, the auxiliary heat source device 11, the gas controller K, and the like. The total volume of the raw material and fuel supplied to the fuel consuming device via the raw material and fuel flow path L6 is measured (# 25). Next, as shown in FIG. 3, the abnormality determination unit H of the fuel gauge Y has a cumulative time during which the measured value (total volume) of the volume flow meter Fb is within a predetermined range (45 L / h ± 5%) for a predetermined period. It is determined whether or not the predetermined condition of the predetermined time (1 hour) or more is satisfied in the middle (30 days) (# 26).

Another fuel consuming device may be used in the abnormality determination operation mode in which a predetermined amount of raw material fuel is supplied to the solid oxide fuel cell 1 via the raw material fuel flow path L1. In this case, the measured value (total volume) of the volume flow meter Fb is out of the predetermined range. Therefore, in the present embodiment, the cumulative operation time of the abnormality determination operation mode is during the predetermined period (30 days) unless there is a gas leak. The operation time is set with a margin so as to be a predetermined time (1 hour). As a result, gas leaks from the raw material and fuel channels L1 and L6 can be reliably detected. Moreover, since the measured value (total volume) of the volume flow meter Fb is defined by the cumulative time within the predetermined range as a predetermined condition in the abnormality determination of the abnormality determination unit H, the power load of the power load unit 3 is small. Occasionally, the abnormality determination operation mode can be executed, and efficient operation of the fuel cell device X can be realized.

As a result of the determination of # 26, if the cumulative time in which the measured value (total volume) of the volume flow meter Fb is within the predetermined range (45 L / h ± 5%) has not reached the predetermined time (1 hour) (# 26No. ), The abnormality determination unit H determines whether or not a predetermined period (30 days) has elapsed (# 27). If the predetermined period (30 days) has not passed (# 27No), the steps # 22 to # 26 are repeated, and if the predetermined period (30 days) has passed (# 27Yes), the abnormality determination unit H determines the abnormality. It is determined that a gas leak has occurred (abnormal) from the raw material / fuel flow paths L1 and L6 (# 28). When the abnormality determination unit H determines that a gas leak has occurred from the raw material / fuel flow paths L1 and L6, the abnormality determination unit H issues a gas leak alarm and executes a gas shutoff operation.

As a result of the determination of # 26, if the cumulative time within the predetermined range (45 L / h ± 5%) of the measured value (total volume) of the volume flow meter Fb has reached the predetermined time (1 hour) (# 26Yes). ), The abnormality determination unit H determines that there is no gas leak, resets the cumulative time (sets the cumulative time to zero), and stops the execution of the abnormality determination operation mode until the next predetermined period is reached (# 29).

As described above, in the present embodiment, the abnormality determination operation mode for supplying a predetermined amount of raw fuel to the solid oxide fuel cell 1 is executed regardless of which operation mode the operation control device C is executing. To do. In this abnormality determination operation mode, since a predetermined amount of raw fuel is supplied to the solid oxide fuel cell 1, unless the raw fuel is used in other fuel consuming devices, the raw fuel measured by the fuel gauge Y The total volume is within a predetermined range. On the other hand, when gas leaks from the raw material / fuel flow paths L1 and L6, the total volume of the raw material and fuel measured by the fuel gauge Y in the abnormality determination operation mode is out of the predetermined range. As a result, the abnormality determination unit H determines that the raw material / fuel flow paths L1 and L6 are abnormal, assuming that the predetermined conditions are not satisfied.

That is, it is possible to detect a gas leak from the raw material / fuel flow paths L1 and L6 by forcibly executing the abnormality determination operation mode while the power generation is being continued by the normal operation of the fuel cell device X. It becomes. Therefore, it has been possible to provide a fuel cell system that can support all operation modes and can determine gas leakage with a simple configuration without stopping the operation of the fuel cell device X.

[Another Embodiment]
<1>
As shown in FIG. 1, the fuel gauge Y includes a communication interface (an example of a communication mechanism) provided in the operation control device C and a communication unit I (an example of a communication mechanism) capable of transmitting and receiving various data by wire or wirelessly. It may be composed of a smart meter. In this case, the abnormality determination unit H detects the abnormality determination operation mode via the communication unit I. In this way, if a communication mechanism is provided between the fuel cell device X and the fuel gauge Y, the flow rate information of the fuel cell device X can be acquired by the fuel gauge Y, and the abnormality determination operation mode is detected in real time. it can. As a result, the fuel gauge Y can more reliably detect gas leaks from the raw material and fuel flow paths L1 and L6 by operating the abnormality determination unit H when the fuel cell device X is in the abnormality determination operation mode. it can.

<2>
The operation control device C acquires a determination result by the abnormality determination unit H via the communication mechanism, and the operation control device C has a predetermined time (for example, 1 hour) or more during a predetermined period (for example, 30 days). When an affirmative result satisfying the conditions is obtained, the abnormality determination operation mode may be canceled. If the abnormality determination operation mode of the fuel cell device X is canceled when an affirmative result satisfying a predetermined condition is obtained as in the present embodiment, normal operation is possible from the release to the next determination. Efficient operation of the fuel cell device X can be realized.

<3>
The total volume of raw materials and fuel measured by the volume flow meter Fb of the fuel gauge Y varies depending on the temperature, device deterioration, and the like. Therefore, there is a possibility that an error may occur between the predetermined amount measured by the mass flow meter Fa of the fuel cell device X and the predetermined amount measured by the volume flow meter Fb of the fuel gauge Y. Therefore, as a predetermined amount of the abnormality determination operation mode, a plurality of flow rate patterns having different flow rates of raw materials and fuel may be combined. FIG. 4 shows an example in which 45 L / h, 45 L / h × 1.08 and 45 L / h × 0.92 are combined as a plurality of flow rate patterns, and the plurality of flow patterns are switched every hour. As a result, the probability that the volume of the raw material and fuel supplied to the solid oxide fuel cell 1 will be within a predetermined range is increased, and the fluctuation error of the total volume of the raw materials and fuel measured by the fuel gauge Y can be absorbed. Therefore, gas leaks from the raw material and fuel flow paths L1 and L6 can be detected more reliably. A plurality of flow rate patterns may be changed based on the outside air temperature measured by the outside air temperature sensor T1.

<4>
In the above embodiment, specific numerical values have been given to explain control examples performed in the fuel cell system, but these numerical values are described for exemplification purposes and can be changed as appropriate.

The configuration disclosed in the above-described embodiment (including another embodiment, the same shall apply hereinafter) can be applied in combination with the configuration disclosed in other embodiments as long as there is no contradiction. Moreover, the embodiment disclosed in the present specification is an example, and the embodiment of the present invention is not limited to this, and can be appropriately modified without departing from the object of the present invention.

The present invention can be applied to a fuel cell system including a solid oxide fuel cell.

1: Solid oxide fuel cell 3: Power load unit 4: Heat load unit 11: Auxiliary heat source device (other fuel consumption equipment)
C: Operation control device (operation control unit, communication mechanism)
Fb: Volumetric flowmeter (measuring unit)
H: Abnormality judgment unit (judgment unit)
I: Communication unit (communication mechanism)
K: Gas stove (other fuel consuming equipment)
L1: Raw material / fuel flow path (fuel supply path)
L6: Raw material / fuel flow path (fuel supply path)
X: Fuel cell device Y: Fuel gauge

Claims (5)

A solid oxide fuel cell capable of supplying the electric power generated by the operation to the power load unit and the heat generated by the operation to the heat load unit, and an operation control unit for controlling the operation of the solid oxide fuel cell. With a fuel cell device,
A measuring unit that measures the total flow rate of fuel supplied to the solid oxide fuel cell and other fuel consuming devices via the fuel supply path, and the fuel supply based on the total flow rate measured by the measuring unit. A fuel gauge having a determination unit for determining the presence or absence of an abnormality in the road is provided.
The operation control unit is configured to be capable of executing a plurality of operation modes, and regardless of which of the operation modes is being executed, a predetermined amount of the solid oxide fuel cell is used instead of the operation mode. Execute the abnormality judgment operation mode to supply the fuel of
When the cumulative time during which the total flow rate is within the predetermined range is equal to or longer than the predetermined time, the determination unit resets the cumulative time, and the cumulative time is less than the predetermined time during the predetermined period. A fuel cell system that determines that the fuel supply path is abnormal. The fuel cell system according to claim 1, wherein the operation control unit executes the abnormality determination operation mode by combining a plurality of flow patterns having different fuel flow rates as the predetermined amount. The fuel cell system according to claim 1 or 2, wherein the operation control unit executes the abnormality determination operation mode based on a set operation time. A communication mechanism for communicating between the operation control unit and the determination unit is further provided.
The operation control unit acquires the determination result by the determination unit via the communication mechanism, and obtains the determination result.
The fuel cell system according to any one of claims 1 to 3, wherein the operation control unit releases the abnormality determination operation mode when the cumulative time is equal to or longer than the predetermined time during the predetermined period. The fuel cell system according to claim 4, wherein the determination unit detects the abnormality determination operation mode via the communication mechanism.

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