JP6744250B2 - Fuel cell device and control method - Google Patents

Description

The present disclosure relates to a fuel cell device and a control method.

BACKGROUND ART A fuel cell device is known in which a reforming reaction of a fuel gas such as city gas is performed and the resulting hydrogen is used to generate electricity. Such a fuel cell device is installed, for example, in each customer facility. In that case, the fuel cell device generates electric power using city gas and supplies the electric power to the load device of the customer facility.

In the customer facility, the fuel cell device receives gas supply via a gas meter. The gas meter has a safety function of automatically cutting off the gas supply when detecting an abnormality in the gas supply. For example, the gas meter determines that a gas leak has occurred and shuts off the gas supply when the gas flow rate is kept within a predetermined range for a predetermined gas leak detection time (for example, 270 minutes).

In order for the fuel cell device to contribute to stable power generation, continuous supply of gas is required. However, if the gas meter cuts off the gas supply for safety, the continuous supply of gas to the fuel cell device is hindered. As a technique for ensuring the continuous supply of gas to the fuel cell device under such restrictions, for example, in Patent Document 1, a gas leak detection of a gas meter is suppressed by providing a predetermined gas cutoff period, and gas cutoff is avoided. A thermal device is disclosed.

JP, 2013-213609, A

There is room for further improvement in suppressing the occurrence of gas leak detection by the gas meter.

The present disclosure relates to a fuel cell device and a control method that suppress gas leak detection by a gas meter.

A fuel cell device according to an embodiment of the present disclosure includes a hot module and a control unit. The hot module generates power by reforming the gas supplied through the gas meter. When the flow rate of the gas supplied to the hot module continues within a predetermined range for a predetermined time, the control unit controls the flow rate of the gas to be outside the predetermined range. In the grid interconnection operation , the control unit increases the flow rate of the gas when the predetermined range is equal to or less than the threshold value, and decreases the flow rate of the gas when the predetermined range exceeds the threshold value. In the self-sustained operation, the control unit increases the flow rate of the gas regardless of the magnitude relationship between the predetermined range and the threshold value.

A control method according to an embodiment of the present disclosure is a control method of a fuel cell device including a hot module that generates power by reforming a gas supplied through a gas meter. The control method controls the flow rate of the gas to be out of the predetermined range when the flow rate of the gas supplied to the hot module continues within a predetermined range for a predetermined time. In the system interconnection operation , the control method increases the flow rate of the gas when the predetermined range is less than or equal to a threshold value, and decreases the gas flow rate when the predetermined range exceeds the threshold value. In the self-sustaining operation, the control method increases the flow rate of the gas regardless of the magnitude relation between the predetermined range and the threshold value.

According to an embodiment of the present disclosure, a fuel cell device and a control method that suppress gas leak detection by a gas meter are realized.

1 is a block diagram showing a schematic configuration of a fuel cell device according to an embodiment of the present disclosure. It is a flow chart which shows operation of a control part. It is a figure which shows the aspect in which the flow rate of gas is reduced-controlled according to operation|movement of a control part. It is a figure which shows a mode that a load follows when the flow rate of gas is controlled to decrease. It is a figure which shows the aspect which the flow volume of gas is controlled to increase with operation|movement of a control part. It is a figure which shows a mode that a load follows when the flow rate of gas is controlled to increase.

Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings.

[Schematic Configuration of Fuel Cell Device 1]
As shown in FIG. 1, the fuel cell device 1 is provided in a consumer facility such as a general home or a commercial and industrial facility. The fuel cell device 1 includes a pressure switch 11, a first electromagnetic valve 12a, a second electromagnetic valve 12b, a gas pump 13, a gas flow meter 14, a hot module 20, a power conditioner 30, and a storage unit 110. The control unit 120, the input unit 210, and the clock unit 220 are included. The hot module 20 has a reforming unit 21 and a fuel cell unit 22. In FIG. 1, a solid line indicates a path for gas, electric power, water, or the like. The alternate long and short dash line indicates the communication path.

The pressure switch 11 detects the pressure of the gas supplied via the external gas meter 60. The pressure switch 11 outputs a signal (contact signal) when detecting the set predetermined pressure.

The first solenoid valve 12a and the second solenoid valve 12b are two gas solenoid valves that open and close the gas supply path to the hot module 20. The first electromagnetic valve 12a and the second electromagnetic valve 12b open and close the gas supply path using the force of an electromagnet. By arranging the first solenoid valve 12a and the second solenoid valve 12b in series, even if one gas solenoid valve fails to stop the gas supply, the other gas solenoid valve is operated. As a result, the gas supply can be stopped more reliably. Three or more gas solenoid valves may be used.

The gas pump 13 adjusts the flow rate of gas supplied to the hot module 20 by swinging a diaphragm provided inside the pump head.

The gas flow meter 14 is a flow meter for measuring the flow rate of gas supplied to the hot module 20. The gas flow meter 14 measures the flow rate of gas. The gas flow meter 14 transmits the measured gas flow rate information to the control unit 120 by wire communication or wireless communication.

The reforming unit 21 of the hot module 20 produces hydrogen, which is a fuel for the fuel cell, from water and methane contained in the gas supplied through the gas meter 60. The reforming unit 21 causes a reforming reaction of water and methane to obtain a product containing hydrogen (reformed gas). The reforming unit 21 is kept at a temperature suitable for the reforming reaction by the heater.

The fuel cell unit 22 of the hot module 20 has one or more fuel cells. For example, the fuel cell unit 22 has a cell stack in which a plurality of fuel cells are stacked. The reformed gas is supplied from the reforming unit 21 to the fuel cell unit 22. Air is supplied to the fuel cell unit 22. The fuel cell unit 22 uses hydrogen in the reformed gas and oxygen in the air to generate electricity. Specifically, the fuel cell unit 22 reacts hydrogen with oxygen to generate water and electricity. The fuel cell unit 22 supplies the generated DC power to the power conditioner 30. The fuel cell unit 22 discharges high temperature exhaust gas. The exhaust gas may include, for example, hydrogen, carbon dioxide, carbon monoxide, etc. in the reformed gas. The fuel cell unit 22 supplies the exhaust gas to the heat exchanger 40.

The power conditioner 30 converts DC power from the fuel cell unit 22 into AC power and outputs the AC power. The power conditioner 30 supplies the converted AC power to the power load 82 via the distribution board 80. When the DC power from the fuel cell unit 22 is sufficiently supplied, the power conditioner 30 supplies the DC power from the fuel cell unit 22 to each component of the fuel cell device 1 to drive each component. To do. On the other hand, when the DC power from the fuel cell unit 22 cannot be sufficiently secured, the power conditioner 30 converts AC power from the outside, for example, AC power from the grid 81 into DC power. Then, the power conditioner 30 supplies the converted DC power to each component of the fuel cell device 1 to drive each component.

The power conditioner 30 may perform so-called load following control that adjusts the output power according to the power consumption of the power load 82. For example, the power conditioner 30 detects the current output by the hot module 20 and performs load follow-up control based on the detected current. The power conditioner 30 may be an output power detection unit that detects the output power information and transmits the detected output power information to the control unit 120.

The heat exchanger 40 is connected to the hot water storage tank 70 via the circulation path 41. The hot water storage tank 70 is provided in the customer facility. The water stored in the hot water storage tank 70 circulates in the circulation path 41 by, for example, a circulation pump. The heat exchanger 40 uses the heat energy of the supplied exhaust gas to heat the water circulating between it and the hot water storage tank 70 via the circulation path 41.

The storage unit 110 has, for example, a primary storage device or a secondary storage device. The storage unit 110 has, for example, a semiconductor memory, a magnetic memory, an optical memory, or the like. The semiconductor memory includes, for example, a volatile memory or a non-volatile memory. The magnetic memory includes, for example, a hard disk or a magnetic tape. The optical memory includes, for example, a CD (Compact Disc), a DVD (Digital Versatile Disc), a BD (Blu-ray (registered trademark) Disc), or the like. The storage unit 110 stores various information and programs used for the operation of the fuel cell device 1.

The control unit 120 has one or more processors. The processor includes a dedicated processor specialized for a specific process or a general-purpose processor that executes a specific function by reading a specific program. The control unit 120 controls the operation of the entire fuel cell device 1. Specifically, the control unit 120 controls the first electromagnetic valve 12a and the second electromagnetic valve 12b to start and stop the gas supply. The control unit 120 controls the gas pump 13 to adjust the gas flow rate based on the gas flow rate information received from the gas flow meter 14. The control unit 120 controls the gas pump 13 to adjust the gas flow rate based on the information on the output power received from the power conditioner 30. Furthermore, the control unit 120 receives, for example, information indicating the state of a relay provided between the distribution board 80 and the system 81, and based on the information, the fuel cell device 1 is in a self-sustaining operation, or It is determined whether or not the system interconnection operation in which the system 81 is connected to output AC power.

The storage unit 110 and the control unit 120 are configured as, for example, one control device 100. The control device 100 is, for example, an arbitrary information processing device such as a computer.

The input unit 210 receives input from the user. The input unit 210 includes, for example, operation buttons or a touch panel.

The clock unit 220 is a timer that measures time. The clock unit 220 is, for example, an RTC (Real Time Clock). The clock unit 220 may be mounted as a function of the control unit 120. The clock unit 220 may be synchronized with the time information received from the time server via the network.

The input unit 210 and the clock unit 220 are configured as, for example, one remote controller 200. The remote controller 200 exchanges signals with the control unit 120 by, for example, wireless communication. The remote controller 200 operates by a power source different from the configuration of the fuel cell device 1 other than the remote controller 200, for example. The remote controller 200 operates by a power source different from the configuration of the fuel cell device 1 other than the remote controller 200, so that the timekeeping unit 220 can maintain the timekeeping even during a power failure.

The gas meter 60 is a detector that detects the flow rate of gas supplied to the fuel cell device 1. The gas meter 60 detects, for example, the flow rate of gas per 30 seconds to 60 seconds. When the gas flow rate satisfies a predetermined condition, the gas meter 60 determines that an abnormality has occurred in the gas supply and automatically shuts off the gas supply. Specifically, the gas meter 60 includes a plurality of gas leakage detection flow rate ranges (for example, a range of 0.1 to 0.3 (m ³ /h), a range of 0.3 to 0.6 (m ³ /h), 0. 6 to 0.8 (m ³ /h) range) is stored. When the gas meter 60 continuously detects a state where the gas flow rate is within the same gas leak detection flow rate range for a predetermined gas leak detection time (for example, 270 minutes), a gas leak occurs due to forgetting to turn off the gas. If it is determined that the gas is present, the gas supply is shut off. The gas meter 60 resets the count of the gas leak detection time when it continuously deviates from the gas leak detection flow rate range for a predetermined gas leak detection release time (for example, 3 minutes).

[Operation of Fuel Cell Device 1]
2 to 6 are diagrams for explaining the operation of the fuel cell device 1. 3 to 6, the vertical axis represents the flow rate of the gas supplied to the hot module 20, the horizontal axis represents the passage of time, and the time change of the flow rate of the gas supplied to the hot module 20 is shown. 3 to 6, the gas flow rate is divided into a first gas flow rate range R ₁ , a second gas flow rate range R ₂ , and a third gas flow rate range R ₃ . The first gas flow rate range R ₁ , the second gas flow rate range R ₂ , and the third gas flow rate range R ₃ correspond to the gas leak detection flow rate ranges of the gas meter 60.

The control unit 120 receives the gas flow rate information from the gas flow meter 14 as needed. The control unit 120 calculates the average value of the flow rate of the gas supplied to the hot module 20 for each constant sampling time (for example, 30 seconds) at any time based on the received gas flow rate information. As illustrated in FIG. 2, the control unit 120 determines whether the calculated gas flow rate continues within the gas leak detection flow rate range for a first time T ₁ (for example, 240 minutes) (step S101). The first time T ₁ is shorter than the gas leak detection time of the gas meter 60. The control unit 120 makes the above determination, for example, every time the first time T ₁ elapses. The control unit 120 makes the above determination, for example, for each cycle shorter than the first time T ₁ . When the control unit 120 does not determine that the gas flow rate continues for the first time T ₁ within the same gas leak detection flow rate range (No in step S101), the control unit 120 returns to step S101. On the other hand, when the control unit 120 determines that the gas flow rate continues within the same gas leak detection flow rate range for the first time T ₁ (Yes in step S101), the process proceeds to step S102.

The control unit 120 determines whether or not the fuel cell device 1 is in a self-sustaining operation of disconnecting from the grid 81 and outputting AC power (step S102). If the control unit 120 determines that the fuel cell device 1 is in the self-sustaining operation (Yes in step S102), the process proceeds to step S107. On the other hand, when the control unit 120 determines that the fuel cell device 1 is in the grid interconnection operation (No in step S102), the process proceeds to step S103.

The control unit 120 determines whether or not the gas leak detection flow rate range used in the determination in step S101 is equal to or less than the threshold value J (step S103). When the control unit 120 determines that the gas leak detection flow rate range exceeds the threshold value J (No in step S103), the process proceeds to step S104. On the other hand, when the control unit 120 determines that the gas leak detection flow rate range is equal to or less than the threshold value J (Yes in step S103), the process proceeds to step S107.

The threshold value J is a value larger than the minimum gas flow rate B, as shown in FIGS. The minimum gas flow rate B is the minimum gas flow rate required for the hot module 20 to maintain power generation. When the flow rate of the gas supplied to the hot module 20 is lower than the minimum gas flow rate B, the durability of the fuel cell device 1 may be reduced. In the examples shown in FIGS. 3 to 6, the threshold value J is located on the boundary line between the first gas flow rate range R ₁ and the second gas flow rate range R _2, and is the maximum value of the first gas flow rate range R ₁ . Therefore, when the gas flow rate is in the first gas flow rate range R ₁ , the control unit 120 determines that the gas leak detection flow rate range is equal to or less than the threshold value J. When the gas flow rate is in the second gas flow rate range R ₂ or the third gas flow rate range R ₃ , the control unit 120 determines that the gas leak detection flow rate range exceeds the threshold value J. The threshold value J does not have to be the maximum value of the first gas flow rate range R ₁ . The threshold value J is, for example, an arbitrary value sandwiched between the minimum value and the maximum value of the first gas flow rate range R ₁ . The threshold value J does not depend on the power consumption of the power load 82.

In the step S104, the control unit 120 reduces the gas flow rate so that the gas flow rate is out of the gas leak detection flow rate range, and proceeds to the step S105. For example, as shown in FIG. 3, when the gas flow rate continues to be in the second gas flow rate range R ₂ for the first time T ₁ , the control unit 120 reduces the gas flow rate by the change control amount C. The change control amount C is a predetermined value stored in the storage unit 110 in advance. The change control amount C is a fluctuation range that the fuel cell device 1 can tolerate as a change amount of the gas flow rate. The change control amount C is, for example, greater than or equal to the size of the gas leak detection flow rate range. In that case, the reduced gas flow rate is within the first gas flow rate range R ₁ that is smaller than the second gas flow rate range R ₂ .

The control unit 120 determines whether or not the output power has increased in the process of step S105. The output power changes, for example, when the control unit 120 performs load following control. The control unit 120 increases the flow rate of the gas when the output power increases and decreases the flow rate of the gas when the output power decreases when the normal control is performed. When the control unit 120 does not determine that the output power has increased (No in step S105), the process proceeds to step S110. When the control unit 120 determines that the output power has increased (Yes in step S105), the control unit 120 suppresses the increase in gas flow rate (step S106), and proceeds to step S110.

In FIG. 5, the flow rate of the gas that is increased according to the increase in the output power when the control unit 120 follows the normal control is indicated by a dashed-dotted line. The control unit 120 does not increase the gas flow rate from the value reduced in the step S104 even if the output power increases. On the other hand, when the output power decreases, the control unit 120 further decreases the gas flow rate from the value controlled in the process of step S104. Hereinafter, the control performed by the control unit 120 in steps S104, S105, and S106 will be referred to as gas flow rate reduction control.

In the step S107, the control unit 120 increases the gas flow rate so that the gas flow rate is out of the gas leak detection flow rate range, and proceeds to the step S108. For example, as shown in FIG. 4, when the gas flow rate remains in the first gas flow rate range R ₁ for the first time T ₁ , the control unit 120 increases the gas flow rate by the change control amount C. The change control amount C corresponds to the size of the gas leak detection flow rate range, for example. In that case, the flow rate of the gas after the increase is within the second gas flow rate range R ₂ which is larger than the first gas flow rate range R ₁ .

The control unit 120 determines whether or not the output power has decreased in the process of step S108. When the control unit 120 does not determine that the output power has decreased (No in step S108), the process proceeds to step S110. When the control unit 120 determines that the output power has decreased (Yes in step S108), the control unit 120 suppresses the decrease in the gas flow rate (step S109), and proceeds to step S110.

In FIG. 6, the flow rate of the gas that is decreased in accordance with the decrease in the output power when the control unit 120 follows the normal control is indicated by the alternate long and short dash line. The control unit 120 does not decrease the gas flow rate from the value increased in the process of step S107 even if the output power decreases. On the other hand, when the output power increases, the control unit 120 further increases the gas flow rate from the value controlled in the process of step S104. Hereinafter, the control performed by the control unit 120 in steps S107, S108, and S109 is referred to as gas flow rate increase control. The above-described gas flow rate decrease control and gas flow rate increase control are collectively referred to as gas flow rate change control.

The control unit 120 determines whether or not the second time T ₂ (for example, 5 minutes) has elapsed since the control of step S104 or S107 in the process of step S110. The second time T ₂ is longer than the gas leak detection release time of the gas meter 60 and shorter than the first time T ₁ . When determining that the second time T ₂ has not elapsed (No in step S110), the control unit 120 waits until the second time T _{2 has} elapsed. In other words, the control unit 120 continues the above gas flow rate change control for the second time T ₂ . When reducing the gas flow rate, the control unit 120 requires a predetermined time to reduce the flow rate to the target flow rate. As shown in FIG. 3, when the control unit 120 starts the control to reduce the flow rate of gas from the start time A, the flow rate of gas reaches outside the second gas flow rate range R ₂ after a predetermined time has elapsed. Therefore, when reducing the flow rate of the gas, the control unit 120 reduces the flow rate of the gas over the third time T ₃ which is longer than the second time T ₂ . When determining that the second time T _{2 has} elapsed (Yes in step S110), the control unit 120 cancels the gas flow rate change control (step S111) and returns to the step S101.

As described above, when the flow rate of the gas supplied to the hot module 20 continues for the first time T ₁ within the gas leak detection flow rate range, the fuel cell device 1 controls the gas flow rate to detect the gas leak detection flow rate. It is out of range. The fuel cell device 1 increases the gas flow rate when the gas leak detection flow rate range is equal to or less than the threshold value J. The fuel cell device 1 reduces the gas flow rate when the gas leak detection flow rate range exceeds the threshold value J. By doing so, the fuel cell device 1 can suppress the gas leak detection by the gas meter 60 and prevent the gas flow rate from falling below the minimum gas flow rate B. Further, when the output power does not increase when the control unit 120 increases the gas flow rate, the hot module 20 accumulates heat and lowers the durability, but the fuel cell device 1 has a case where the predetermined range exceeds the threshold value J. Since the gas flow rate is reduced, the increase in gas flow rate can be minimized.

As described above, in the state where the gas flow rate is increased, the fuel cell device 1 maintains the gas flow rate above a certain level even when the output power decreases. By doing so, the fuel cell device 1 can suppress the gas leak detection by the gas meter 60 even if the output power is reduced by the load following control, for example.

As described above, in the state where the gas flow rate is reduced, the fuel cell device 1 suppresses the gas flow rate to some extent or less even when the output power increases. By doing so, the fuel cell device 1 can suppress the gas leak detection by the gas meter 60 even if the output power is increased by the load following control, for example.

As described above, in the self-sustaining operation, when the gas flow rate continues within the predetermined range for the first time T ₁ , the fuel cell device 1 controls the gas flow rate regardless of the magnitude relationship with the threshold value J of the gas flow rate. increase. By doing so, the fuel cell device 1 is prepared in advance for increasing the flow rate of gas due to load following.

The present invention is not limited to the configurations specified in the above-described embodiments, and various modifications can be made without departing from the scope of the invention described in the claims. For example, it is possible to rearrange the functions and the like included in each constituent unit and each step so as not to logically contradict, and to combine or divide a plurality of constituent units or steps into one. Is. Further, although the present disclosure has been described centering on the fuel cell device 1, the present disclosure can be realized as a method of controlling the fuel cell device 1 by a computer, a program, or a storage medium storing the program. It should be understood that the scope of the disclosure also includes these.

1 Fuel Cell Device 11 Pressure Switch 12a First Solenoid Valve 12b Second Solenoid Valve 13 Gas Pump 14 Gas Flow Meter 20 Hot Module 21 Reforming Unit 22 Fuel Cell Unit 30 Power Conditioner 40 Heat Exchanger 41 Circulation Path 60 Gas Meter 70 Hot Water Tank 80 Distribution board 81 System 82 Power load 100 Control device 110 Storage unit 120 Control unit 200 Remote controller 210 Input unit 220 Timing unit A Start time B Minimum gas flow rate C Change control amount J Threshold value R ₁ First gas flow rate range R ₂ No. 2 Gas flow rate range R ₃ Third gas flow rate range T ₁ First time (predetermined time)
T _2nd time T ₃ 3rd time

Claims (5)

A hot module that generates power by reforming the gas supplied through the gas meter,
When the flow rate of the gas supplied to the hot module continues within a predetermined range for a predetermined time, a control unit that controls the flow rate of the gas to be outside the predetermined range is provided,
The control unit is
During system interconnection operation, the flow rate of the gas is increased when the predetermined range is equal to or less than a threshold value, and the flow rate of the gas is decreased when the predetermined range exceeds the threshold value .
A fuel cell device that increases the flow rate of the gas regardless of the magnitude relationship between the predetermined range and the threshold value during self-sustaining operation . Further comprising an output power detection unit for detecting output power generated by the hot module and output to the outside,
The control unit suppresses a decrease in the flow rate of the gas when the output power decreases in a state where the flow rate of the gas is increasing,
The fuel cell device according to claim 1. Further comprising an output power detection unit for detecting output power generated by the hot module and output to the outside,
The control unit suppresses an increase in the flow rate of the gas when the output power increases in a state where the flow rate of the gas is decreasing,
The fuel cell device according to claim 1. The gas meter shuts off the gas supply when the flow rate of the gas supplied to the hot module continues within the gas leak detection flow rate range for the gas leak detection time.
The fuel cell device according to any one of claims 1 to 3 . A method for controlling a fuel cell device comprising a hot module for generating power by reforming a gas supplied through a gas meter,
When the flow rate of the gas supplied to the hot module continues within a predetermined range for a predetermined time, the flow rate of the gas is controlled to be outside the predetermined range,
During system interconnection operation, the flow rate of the gas is increased when the predetermined range is equal to or less than a threshold value, and the flow rate of the gas is decreased when the predetermined range exceeds the threshold value .
In the self-sustaining operation, regardless of the magnitude relation between the predetermined range and the threshold value, the flow rate of the gas is increased.
Control method.

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