JP2014116069A - Fuel cell system - Google Patents

Abstract

A novel fuel cell system capable of quickly detecting a valve failure without using a pressure detector.
A control unit 20 of a fuel cell system 1 selectively oxidizes when an open signal is sent to an oxidant supply valve 16 and an oxidant discharge valve 17 while fuel gas is being supplied to the fuel cell 2. When the supply amount of the oxidant gas flowing through the air flow path 15 is increased, it is possible to detect the valve closing failure in the start-up process, which is an early stage before starting the power generation process, by detecting that the valve is closed. In addition, the reliability of the combustion battery system can be improved.
[Selection] Figure 1

Description

  The present invention relates to a fuel cell system in which a valve is provided in a flow path for supplying an oxidant gas to a fuel cell and / or a flow path for discharging the oxidant gas from the fuel cell.

  A fuel cell is a device that generates electric power and heat by generating an electrochemical reaction between a fuel gas containing hydrogen and an oxidant gas containing oxygen. In a fuel cell system including such a fuel cell, Valves for opening and closing the respective channels are provided in the channel for supplying the oxidizing gas to the battery and the channel for discharging the oxidizing gas from the fuel cell.

  In such a fuel cell system, it is important to detect a failure of these valves. For example, the valve provided in the flow path for supplying the oxidant gas is closed despite the signal of the opening command being sent, and when the valve is left in the closed state, power generation of the fuel cell is started. I don't know anything abnormal. Since fuel gas containing hydrogen is supplied even in this closed state, it is necessary to detect a valve failure before the fuel cell starts power generation.

  In contrast, for example, Patent Document 1 proposes a fuel cell system configured as shown in FIG. 5 as a conventional general fuel cell system. FIG. 5 is a schematic diagram showing a configuration of a conventional fuel cell system. A fuel cell system 201 shown in FIG. 5 includes a fuel cell 202 that generates power using fuel gas and an oxidant gas containing oxygen, an air blower 213 that supplies the fuel cell 202 with the oxidant gas, an air blower 212, An oxidant gas supply channel 213 connecting the fuel cell 202, an oxidant gas discharge channel 214 for discharging the oxidant gas from the fuel cell 202, and an oxidant supply valve for opening and closing the oxidant gas supply channel 213. 216 and an oxidant discharge valve 217 that opens and closes the oxidant gas discharge passage.

JP 2009-94000 A

  However, the fuel cell system 201 described in Patent Document 1 includes a pressure detection unit 222 that detects the pressure in the flow path between the oxidant supply valve 216 and the oxidant discharge valve 217, and the pressure detection unit 222. Is based on the slope of the change in pressure over time, and determines whether the oxidant supply valve 216 and the oxidant discharge valve 217 are malfunctioning. There is a problem that it takes time to detect a valve failure. From that point of view, there was still room for improvement.

  That is, an object of the present invention is to quickly detect a valve failure in view of the problems of the conventional fuel cell system that determines the malfunction of the valve based on the slope of the time change of the pressure detected by the pressure detector as described above. It is an object of the present invention to provide a novel fuel cell system that can be detected.

As a result of intensive studies in view of the conventional problems as described above, the present inventors have provided an oxidant gas supply flow in order to provide a novel fuel cell system capable of quickly detecting a valve failure. One or more valves are provided in at least one of a flow path portion from the branch portion to the fuel cell and the oxidant gas discharge flow path in the path, and the fuel cell. When starting the operation of the system and before starting the supply of fuel gas to the fuel cell, when the start signal is sent to the oxidant gas supply unit and the open signal is sent to all the one or more valves In addition, it is effective to control the fuel cell system to continue operation when the branched supply amount of the oxidant gas measured by the oxidant gas supply amount measurement unit is within a predetermined range. The headline and the present invention were completed.

That is, the present invention
A fuel cell system including a fuel cell that generates power using a fuel gas containing hydrogen and an oxidant gas containing oxygen,
A fuel gas supply unit for supplying fuel gas to the fuel cell;
An oxidant gas supply unit for supplying an oxidant gas to the fuel cell;
An oxidant gas supply channel for supplying oxidant gas to the fuel cell from the oxidant gas supply unit;
An oxidant gas discharge passage for discharging the oxidant gas from the fuel cell;
An oxidant gas branch flow path branched from the oxidant gas supply flow path;
One provided in at least one of the channel portion between the branch portion of the oxidant gas supply channel and the oxidant gas branch channel to the fuel cell, and the oxidant gas discharge channel With the above valves,
An oxidant gas supply amount measuring unit that is provided in the oxidant gas branch flow channel and measures a branch supply amount of the oxidant gas supplied to the oxidant gas branch flow channel;
A control unit that controls at least an oxidant gas supply unit and one or more valves, and supplies an oxidant gas between the start of operation of the fuel cell system and the start of supply of fuel gas to the fuel cell. When the oxidant gas branch supply amount measured by the oxidant gas supply amount measurement unit is within a predetermined range when an activation signal is sent to the unit and an open signal is sent to all one or more valves And a control unit for controlling the fuel cell system to continue operation,
A fuel cell system is provided.

  Here, the “predetermined range” can be determined in advance by those skilled in the art based on the flow rate of the oxidant gas that normally flows when all of the one or more valves are open. (Hereinafter the same applies).

  By having such a configuration, the fuel cell system of the present invention is normally used in the operation of the fuel cell after starting the operation of the fuel cell system until starting the supply of fuel gas to the fuel cell. Of the oxidant gas supply flow path, the flow path portion from the branch part of the oxidant gas supply flow path to the fuel cell, and the oxidant gas discharge flow path. Therefore, it is possible to quickly determine (detect) a closed failure of one or more valves provided in at least one of the above, and therefore it is possible to reduce the startup energy of the fuel cell system as compared with the conventional case.

  Further, in the configuration of the conventional fuel cell system described in the above-mentioned Patent Document 1, only the detection of a failure in which the valve is open (that is, an open failure) is performed despite the signal of the closing command being sent. However, in the fuel cell system according to the present invention having the above-described configuration, it is possible to detect a failure in which the valve is closed (that is, a closed failure) even though an open command signal is sent. There are advantages.

  Further, in the above conventional fuel cell system, for example, when an abnormal state (closed adhering) occurs in which a solenoid type rubber valve adheres and closes, the cell voltage decreases during the power generation process of the fuel cell. Although the abnormal state can be detected, until the power generation process is started, the abnormal state cannot be detected and the startup energy of the fuel cell system increases, but according to the fuel cell system of the present invention, Until the power generation process is started, the abnormal state can be detected, and this problem can be solved.

In the fuel cell system of the present invention,
The control unit controls the operation of the fuel cell system to stop when the branch supply amount of the oxidant gas measured by the oxidant gas supply amount measurement unit increases from the first specified value.
It is preferable.

  Here, the “first specified value” corresponds to the upper limit value of the “predetermined range”, and this upper limit value is, for example, the oxidant gas when all the one or more valves are open. It is larger than the branch supply amount and is a value of 300% or less of the branch supply amount. The upper limit value is preferably a value of 180% to 220% of the branch supply amount, for example.

  According to such a configuration, if one of the one or more valves to which an open signal is sent is closed, the oxidant gas is not supplied to the fuel cell, and the oxidant gas branch flow path A large amount of oxidant gas is supplied, and a valve closing failure can be reliably detected by using an oxidant gas supply amount measuring unit that is normally used for operation of the fuel cell system. That is, if one of the one or more valves to which an open signal is sent is closed, the oxidant gas is not supplied to the fuel cell, and the oxidant gas branch flowing through the oxidant gas branch passage Since the supply amount increases, it is possible to more reliably detect a valve closing failure by detecting an increase in the branch supply amount of the oxidant gas flowing through the oxidant gas branch flow path, thereby improving the reliability of the fuel cell system. Can be improved.

The fuel cell system of the present invention is
A supply capacity adjusting means for changing the supply capacity of the oxidant gas supply unit based on the branch supply amount of the oxidant gas measured by the oxidant gas supply amount measurement unit;
The control unit controls to stop the operation of the fuel cell system when the supply capacity of the oxidant gas supply unit decreases from the second specified value.
It is preferable.

  Here, the supply capacity adjusting means may be included in the control unit or may be received separately from the control unit, but is controlled by the control unit. The “second specified value” can be determined in advance by those skilled in the art based on the supply capacity of the oxidant gas supply unit when all of the one or more valves are open. It is possible. This second specified value is, for example, smaller than the supply capacity of the oxidant gas supply section when all of the one or more valves are open, and is a value of 10% or more of this supply capacity. The second specified value is preferably, for example, a value of 30% to 70% of the supply capacity.

  According to such a configuration, if one of the one or more valves to which an open signal is sent is closed, the oxidant gas is not supplied to the fuel cell, and the oxidant gas supply amount measurement unit Because the branch supply amount of the oxidant gas measured in step 1 increases, the control unit reduces the supply capacity of the oxidant gas supply unit by the supply capacity adjusting means that changes based on the branch supply amount of the oxidant gas. Can do. Therefore, when performing such feedback control, it is possible to more reliably detect a valve closing failure by detecting a decrease in the supply capacity of the oxidant gas supply unit, and to further improve the reliability of the fuel cell system. it can.

The fuel cell system of the present invention is
A selective oxidizer for removing carbon monoxide in the fuel gas;
The downstream end of the oxidant gas branch channel has a configuration communicating with the selective oxidizer,
It is preferable.

  According to such a configuration, even if the oxidant gas branch channel communicates with the selective oxidizer, the fuel gas having a high hydrogen concentration (purity) can be supplied to the fuel cell, and the reliability of the fuel cell system Can be improved.

The present invention also provides:
A fuel cell system including a fuel cell that generates power using a fuel gas and an oxidant gas containing oxygen,
A fuel gas supply unit for supplying fuel gas to the fuel cell;
An oxidant gas supply unit for supplying an oxidant gas to the fuel cell;
An oxidant gas supply channel for supplying oxidant gas to the fuel cell from the oxidant gas supply unit;
An oxidant gas discharge passage for discharging the oxidant gas from the fuel cell;
An oxidant gas supply flow rate measuring unit that is provided in the oxidant gas supply flow channel or the oxidant gas discharge flow channel and measures the supply amount of the oxidant gas;
One or more valves provided in at least one of the oxidant gas supply channel and the oxidant gas discharge channel;
A control unit that controls at least an oxidant gas supply unit and one or more valves, and supplies an oxidant gas between the start of operation of the fuel cell system and the start of supply of fuel gas to the fuel cell. When the oxidant gas supply amount measured by the oxidant gas supply amount measurement unit is within a predetermined range when an activation signal is sent to the unit and an open signal is sent to all one or more valves. A control unit for controlling the fuel cell system to continue operation;
A fuel cell system is also provided.

  Here, the “predetermined range” can be determined in advance by those skilled in the art based on the flow rate of the oxidant gas that normally flows when all of the one or more valves are open. (Hereinafter the same applies).

  By having such a configuration, the fuel cell system of the present invention is normally used in the operation of the fuel cell after starting the operation of the fuel cell system until starting the supply of fuel gas to the fuel cell. The oxidant gas supply unit can quickly determine (detect) a closed failure of one or more valves provided in at least one of the oxidant gas supply channel and the oxidant gas discharge channel. Therefore, the starting energy of the fuel cell system can be reduced as compared with the conventional case.

  Further, in the configuration of the conventional fuel cell system described in Patent Document 1, only a failure in which the valve is closed (that is, an open failure) is detected even though an open command signal is sent. However, in the fuel cell system of the present invention having the above-described configuration, it is possible to detect a failure in which the valve is open (that is, a closed failure) even though a closing command signal is sent. There are advantages.

  Further, in the above conventional fuel cell system, for example, when an abnormal state (closed adhering) occurs in which a solenoid type rubber valve adheres and closes, the cell voltage decreases during the power generation process of the fuel cell. Although the abnormal state can be detected, until the power generation process is started, the abnormal state cannot be detected and the startup energy of the fuel cell system increases, but according to the fuel cell system of the present invention, Until the power generation process is started, the abnormal state can be detected, and this problem can be solved.

In the fuel cell system of the present invention,
The control unit controls to stop the operation of the fuel cell system when the supply amount of the oxidant gas measured by the oxidant gas supply amount measurement unit is decreased from a third specified value.
It is preferable.

  Here, the “third specified value” corresponds to, for example, a lower limit value of the “predetermined range”, and this lower limit value is the supply of oxidant gas when all of one or more valves are open. Amount.

  According to such a configuration, the oxidant gas is not supplied to the fuel cell if any one of the one or more valves to which the opening signal is sent is closed. A normally-used oxidant gas supply amount measurement unit can be used to reliably detect a valve closing failure, and the reliability of the fuel cell system can be improved.

  In the fuel cell system of the present invention, the valve is not used between the start of the operation of the fuel cell system and the supply of the fuel gas to the fuel cell without using the pressure detector as in the conventional fuel cell system. Can be detected quickly.

Schematic of the fuel cell system in Embodiment 1 of the present invention A series of operational flow charts for confirming the open failure of the oxidant supply valve of the fuel cell system according to Embodiment 1 of the present invention. Schematic of the fuel cell system in Embodiment 2 of the present invention A series of operational flow charts for confirming the open failure of the oxidant supply valve of the fuel cell system according to Embodiment 2 of the present invention Schematic diagram showing the configuration of a conventional fuel cell system

  Hereinafter, preferred embodiments of the fuel cell system of the present invention will be described with reference to the drawings, but the present invention is not limited thereto. In the following description, the same or corresponding members are denoted by the same reference numerals, and redundant description may be omitted. Each drawing is for conceptual description of the present invention, and is easy to understand. Therefore, dimensions, ratios, or numbers may be exaggerated or simplified as necessary.

(Embodiment 1)
[Constitution]
FIG. 1 is a schematic diagram showing a configuration of a fuel cell system 1 according to Embodiment 1 of the present invention.

  The fuel cell system 1 according to the present embodiment is an example of a fuel cell 2 that generates power using a fuel gas containing hydrogen and an oxidant gas containing oxygen, and a fuel gas supply unit that supplies the fuel gas to the fuel cell 2. And a raw material blower 5 which is a raw material gas supply unit for supplying the raw material gas to the hydrogen generator 4.

  The hydrogen generator 4 is supplied with a raw material gas which is a hydrocarbon-based fuel such as city gas or LPG, and reforms using the raw material gas and water vapor to generate a fuel gas having a high hydrogen concentration. The selective oxidizer 3 generates a fuel gas having a reduced carbon monoxide concentration by selectively oxidizing the reformed gas reformed in the reforming section.

  The fuel cell system 1 also includes a combustor 4a of a hydrogen generator 4 that burns and reuses unreacted fuel gas discharged from the fuel cell 2, and a raw material gas utility (not shown). The raw material gas supply flow path 6 that connects the raw material blower 5 and the hydrogen generator 4, the hydrogen generator 4, and the fuel cell 2 are connected, and the fuel gas generated by the hydrogen generator 4 is converted into a fuel cell. 2 and a fuel gas flow path 7 to be introduced into the vehicle 2.

Also, an exhaust gas passage 8 that communicates the fuel cell 2 with the combustor 4a to guide the fuel gas from the fuel cell 2 to the combustor 4a, and a fuel gas passage 7 and an exhaust gas passage that do not go through the fuel cell 2. And a bypass flow path 9 that connects to the second flow path 8. On the bypass channel 9, a bypass valve 10 that communicates / blocks the bypass channel 9, that is, opens and closes, is disposed, and is located between the branch point of the bypass channel 9 on the fuel gas channel 7 and the fuel cell 2. Is provided with an anode inlet valve 11 for opening and closing the fuel gas flow path.

  Further, the fuel cell system 1 includes an air blower 12 as an example of an oxidant gas supply unit that supplies an oxidant gas to the fuel cell 2 and the selective oxidizer 3 for power generation and carbon monoxide removal, and an air blower 12. And an oxidant gas supply passage 13 for communicating the fuel cell 2 and an oxidant gas discharge passage 14 for discharging the oxidant gas from the fuel cell 2 to the atmosphere.

  The fuel cell system 1 also includes a selective oxidant gas flow channel 15 that is a oxidant gas branch flow channel that branches from the oxidant gas supply flow channel 13 and supplies air from the air blower 12 to the selective oxidizer 3, and an oxidant. Oxidant gas flow / blocking provided in the gas supply flow path 13, that is, an oxidant supply valve 16 for opening and closing the oxidant gas supply flow path 13, and an oxidant gas discharge flow path provided in the oxidant gas discharge flow path 14. An oxidant discharge valve 17 that performs flow / blocking, a selective oxidant valve 18 that is provided in the selective oxidant gas flow path 15 and that allows oxidant gas to flow / block, and a selective oxidant air flow path 15 are provided. A selective oxidation flow meter 19 serving as an oxidant gas supply amount measuring unit is provided.

  Here, the control unit 20 is provided in the fuel cell system 1 of the present embodiment, and the control unit 20 includes at least the raw material blower 5, the bypass valve 10, the anode inlet valve 11, the air blower 12, and the oxidant supply. The valve 16, the oxidant discharge valve 17 and the selective oxidation air valve 18 are controlled. More specifically, the control unit 20 is configured so that the supply amount of the oxidant gas detected by the selective oxidation flow meter 19 which is the oxidant gas supply amount measurement unit becomes the oxidant gas supply amount according to the generated power. The supply amount of the oxidant gas is controlled by changing the supply capacity of the air blower 12.

  In the present embodiment, the raw material blower 5 is a raw material gas supply unit that supplies fuel gas to the fuel cell 2, the air blower 12 is an oxidant gas supply unit that supplies oxidant gas to the fuel cell 2, and a selective oxidized air flow channel 15. Is an oxidant gas branch flow path, an oxidant supply valve 16 and an oxidant discharge valve 17 are portions of the oxidant gas supply flow path that are closer to the fuel cell than a branch portion with the oxidant gas branch flow path, and an oxidant gas. One or more valves provided in at least one of the discharge flow paths, and the selective oxidation flow meter 19 are a specific example of an oxidant gas supply amount measurement unit.

  A source gas such as natural gas or LPG is supplied to the hydrogen generator 4 by the source blower 5. In the hydrogen generator 4, the supplied raw material is reformed by steam, and a reformed gas containing hydrogen as a main component is generated. The generated reformed gas is supplied to the selective oxidizer 3, and in the selective oxidizer 3, air is supplied from the air blower 12 through the selective oxidation air flow path 15, and carbon monoxide in the reformed gas is converted using a catalyst. By selectively oxidizing to carbon dioxide, a fuel gas having an extremely low carbon monoxide concentration is generated. The generated fuel gas is supplied to the fuel electrode side of the fuel cell 2.

  On the other hand, the oxidant supply valve 16 and the oxidant discharge valve 17 are opened, and air is supplied to the cathode side of the fuel cell 2 by the air blower 12 through the oxidant gas supply passage 13 as the oxidant gas. Unreacted oxidant gas discharged from the fuel cell 2 without being used for the reaction is discharged to the outside through the oxidant gas discharge channel 14. In the fuel cell 2, in this way, an electrochemical reaction is performed using the supplied fuel gas and oxidant gas, whereby electric power is generated and heat is generated.

Here, if the controller 20 is left in a closed state (hereinafter referred to as “closed failure”) even though it sends an open signal to the oxidant supply valve 16 or the oxidant discharge valve 17, power generation is performed. Until the process is started, it is not known that the oxidant supply valve 16 or the oxidant discharge valve 17 is closed abnormally. Therefore, the oxidant supply valve 16 and the oxidant discharge valve 17 are detected early in order to reduce startup energy. There is a need to.
[Operation]
Hereinafter, a series of specific operations relating to the detection of the closing failure of the oxidant supply valve 16 or the oxidant discharge valve 17 of the fuel cell system 1 in the present embodiment will be described.

  The control unit 20 controls the entire fuel cell system 1 so as to perform a startup process, a power generation process after the startup process, a stop process after the power generation process, and a stop process after the stop process.

  The start-up process is a process for generating fuel gas from the raw material gas in the hydrogen generator 4 in order to supply the fuel gas to be supplied to the fuel cell 2, and the start-up process starts and the hydrogen generator 4 A fuel gas supply step for supplying the fuel gas to the fuel cell 2 after being heated to a temperature capable of generating the fuel gas; and an oxidant gas supply step for supplying the oxidant gas to the fuel cell 2 after the start of the fuel gas supply step; ,have.

  The power generation process is a process that is performed after the start of the oxidant gas supply process and performs power generation of the fuel cell 2. The stop process is a process for performing a stop process of the fuel cell 2 after the power generation process is completed, and the stop process is a state after the stop process and is in a standby state.

  The control unit 20 of the fuel cell system 1 in the present embodiment performs valve failure detection from the start of the startup process to the start of the fuel gas supply process. More specifically, when the control unit 20 sends a closing signal to the valve in a state where the oxidant gas is supplied to the selective oxidizer 3, the control unit 20 selects the oxidant gas branch flow path that is the oxidant gas branch flow path. When the branch supply amount of the oxidant gas flowing through 15 increases from the first predetermined value X (L / min), it is detected that the valve is closed and the fuel cell system 1 is operated. With the function to stop.

  The specified value X is, for example, a branch supply amount Y (L of oxidant gas flowing through the selective oxidant gas flow channel 15 which is an oxidant gas branch flow channel in a state where the oxidant supply valve 16 and the oxidant discharge valve 17 are opened. / Min) is preferably set to a value of 200% or more.

  Here, FIG. 2 is a flowchart showing a series of operation flows for detecting the valve failure of the oxidant supply valve 16 and the oxidant discharge valve 17 in the starting process. When the start of the fuel cell system 1 is started, first, an initial process (steps S101 and S102) for generating a fuel gas containing hydrogen from the raw material gas is started.

  The control unit 20 sends an opening signal to the bypass valve 10 and sends a closing signal to the anode inlet valve 11, the oxidant supply valve 16, the oxidant discharge valve 17, and the selective oxidation air valve 18. Moreover, a starting signal is sent to the raw material blower 5, and a stop signal is sent to the air blower 12 (step S101). As a result, the raw material gas is supplied from the raw material gas utility to the combustor 4 a via the raw material gas supply channel 6, the hydrogen generator 4, and the bypass channel 9 in a state where the raw material gas is boosted to a predetermined pressure by the raw material blower 5. The combustor 4a starts combustion, and the hydrogen generator 4 starts generating fuel gas using the raw material gas.

  In the initial stage of the start-up process, the hydrogen generator 4 is not sufficiently heated, so that the fuel gas generated by the hydrogen generator 4 contains a large amount of carbon monoxide. When fuel gas having a relatively high carbon monoxide concentration is supplied to the fuel cell 2, the catalyst of the anode of the fuel cell 2 is poisoned. Therefore, during the starting process, the fuel gas generated by the hydrogen generator 4 is combusted by the combustor 4 a via the bypass flow path 9.

When the selective oxidation catalyst of the selective oxidizer 3 reaches a temperature at which it can react, the control unit 20 sends an activation signal to the air blower 12 to supply the selective oxidizer gas to the selective oxidizer 3 to the selective oxidation air valve 18. An open signal is sent (step S102).

  Here, the branch supply amount of the oxidant gas supplied to the selective oxidizer 3 is set to a predetermined amount Y (L / min) by which the carbon monoxide in the fuel gas can be reduced by the selective oxidizer 3, and the control unit 20 selects it. The supply capacity of the air blower 12 is adjusted so that the value of the selective oxidation flow meter 19 arranged in the oxidation air flow path 15 becomes Y (L / min).

  As a result, the oxidant gas is supplied to the selective oxidizer 3, and the process proceeds to valve failure detection (steps S103 to S106) of the oxidant supply valve 16 and the oxidant discharge valve 17.

  As a valve failure detection of the oxidant supply valve 16 and the oxidant discharge valve 17, in step S103, the control unit 20 sends an open signal to the oxidant supply valve 16 and the oxidant discharge valve 17, and the selective oxidation flow meter 19 The branch supply amount of the oxidant gas flowing through the selective oxidation air flow path 15 is confirmed.

  At this time, since the control unit 20 sends an open signal to the oxidant supply valve 16 and the oxidant discharge valve 17, the oxidant gas is supplied to the fuel cell 2 and the oxidant gas flowing through the selective oxidant air flow path 15 is supplied. The branch supply is reduced. The control unit 20 has a value that is 50% of the branch supply amount Y (L / min) of the oxidant gas that flows through the selective oxidant air passage 15 in a state where the oxidant supply valve 16 and the oxidant discharge valve 17 are open. If it is equal to or greater than the specified value X (L / min) (Yes in step S104), it is detected that the oxidant supply valve 16 or the oxidant discharge valve 17 is closed, and the oxidant supply valve 16 and the oxidant discharge are detected. The valve 17 is closed (step S105), the closing failure confirmation of the oxidant supply valve 16 and the oxidant discharge valve 17 is finished, and the operation of the fuel cell system 1 is stopped.

  If the branch supply amount of the oxidant gas flowing through the selective oxidation air flow path 15 measured by the selective oxidation flow meter 19 is less than the specified value X (L / min) (No in step S104), the oxidant supply valve 16 Then, it is determined that the oxidant discharge valve 17 is not closed, the oxidant supply valve 16 and the oxidant discharge valve 17 are closed (step S106), the detection of the close failure of these valves is terminated, and the hydrogen generator When the time required for heating 4 passes or the hydrogen generator 4 reaches a predetermined temperature and the carbon monoxide in the fuel gas decreases, the next fuel gas supply process (step S107) is started. .

  As described above, in the present embodiment, the control unit 20 determines that the branch supply amount of the oxidant gas flowing through the selective oxidation air flow path 15 detected by the selective oxidation flow meter 19 is equal to or greater than the specified value X (L / min). It is detected that the valve that has sent the opening signal is closed, and the operation of the fuel cell system 1 can be stopped until the power generation process starts. The operation of the fuel cell 2 can be stopped due to the closing failure of the valve that has sent the opening signal. In addition, the use of the selective oxidation flow meter 19 improves the reliability of the fuel cell system because the valve closing failure can be detected more reliably by the branch supply amount of the oxidant gas flowing through the selective oxidation air flow path 15. can do.

  Note that the air blower 12 is not the branch supply amount of the oxidant gas flowing through the selective oxidation air flow path 15 measured by the selective oxidation flow meter 19 in step S104 of the valve closing failure detection described with reference to FIG. May have a function of detecting that one or more valves that have sent an open signal have a closed failure when the supply capacity of the valve is less than a second predetermined value Z (%). The specified value Z (%) is preferably set to a value equal to or less than 50% of the supply capacity W (%) of the air blower 12 when the oxidant supply valve 16 and the oxidant discharge valve 17 are open, for example. .

In step S104, since the control unit 20 sends an open signal to the oxidant supply valve 16 and the oxidant discharge valve 17, if the oxidant supply valve 16 and the oxidant discharge valve 17 are open, the selective oxidized air flow Since the branch supply amount of the oxidant gas flowing through the passage 15 decreases from the predetermined amount Y (L / min), the control unit 20 increases the supply capacity of the air blower 12 to W (%) or more. On the other hand, if the oxidant supply valve 16 or the oxidant discharge valve 17 is closed, the oxidant gas is not supplied to the fuel cell 2, and therefore, the branch supply amount of the oxidant gas flowing through the selective oxidation air channel 15 is Y ( L / min), and the supply capacity of the air blower 12 does not increase from W (%), so that it is less than the specified value W (%). Therefore, when the supply capacity is less than the specified value Z (%), it can be detected that the valve that has sent the opening signal has an open failure, and the valve closing failure can be reliably determined.

(Embodiment 2)
FIG. 3 is a schematic diagram showing the configuration of the fuel cell system according to Embodiment 2 of the present invention. As shown in FIG. 3, in the fuel cell system 31 of this embodiment, the oxidant gas supply amount measuring unit for measuring the supply amount of oxidant gas is selectively oxidized compared to the fuel cell system 1 shown in FIG. The difference is that the cathode flowmeter 21 is arranged not in the air passage 15 but in the oxidant gas supply passage 13.

  A series of specific operations relating to failure detection of the oxidant supply valve 16 and the oxidant discharge valve 17 of the fuel cell system 31 in the present embodiment will be described.

  If the control unit 20 is left in a closed state (hereinafter referred to as “closed failure”) despite sending an open signal to the oxidant supply valve 16 or the oxidant discharge valve 17, the power generation process is started. Until this is done, it is not known whether the oxidizer supply valve 16 or the oxidizer discharge valve 17 is closed properly. Therefore, it is necessary to detect the oxidizer supply valve 16 and the oxidizer discharge valve 17 closed early.

  The control unit 20 controls the entire fuel cell system 31 to perform a start process, a power generation process after the start process, a stop process after the power generation process, and a stop process after the stop process.

  The start-up process is a process for generating fuel gas from the raw material gas in the hydrogen generator 4 in order to supply the fuel gas to be supplied to the fuel cell 2, and the start-up process starts and the hydrogen generator 4 A fuel gas supply step for supplying the fuel gas to the fuel cell 2 after being heated to a temperature capable of generating the fuel gas; and an oxidant gas supply step for supplying the oxidant gas to the fuel cell 2 after the start of the fuel gas supply step; ,have. The power generation process is a process that is performed after the start of the oxidant gas supply process and performs power generation of the fuel cell 2.

  The control unit 20 of the fuel cell system 31 according to the present embodiment performs valve failure detection from the start of the start process to the start of the fuel gas supply process. The valve failure is detected in a state where is supplied to the fuel cell 2. More specifically, the control unit 20 sends an open signal to the oxidant supply valve 16 and the oxidant discharge valve 17 in a state where the oxidant gas is supplied to the selective oxidizer 3, and the oxidant gas supply amount is reduced. When the value is smaller than the specified value A (L / min) that is the third specified value, it is detected that one of the oxidant supply valve 16 and the oxidant discharge valve 17 is closed.

  The specified value A is measured by, for example, the cathode flow meter 21 because the oxidant gas does not flow through the oxidant gas supply flow path 13 when the oxidant supply valve 16 and the oxidant discharge valve 17 are closed. It is desirable that A (L / min), which is the smallest possible value.

  Here, FIG. 4 is a flowchart showing a series of operation flows for confirming the closing failure of the oxidant supply valve 16 and the oxidant discharge valve 17 in the present embodiment. When the start of the fuel cell system 1 is started, first, an initial process (steps S201 and S202) for generating a fuel gas containing hydrogen from the raw material gas is started.

  The control unit 20 sends an opening signal to the bypass valve 10 and sends a closing signal to the anode inlet valve 11, the oxidant supply valve 16, the oxidant discharge valve 17, and the selective oxidation air valve 18. Moreover, a starting signal is sent to the raw material blower 5, and a stop signal is sent to the air blower 12 (step S201). As a result, the raw material gas is supplied from the raw material gas utility to the combustor 4 a via the raw material gas supply channel 6, the hydrogen generator 4, and the bypass channel 9 in a state where the raw material gas is boosted to a predetermined pressure by the raw material blower 5. The combustor 4a starts combustion, and the hydrogen generator 4 starts generating fuel gas using the raw material gas.

  Since the hydrogen generator 4 is not sufficiently heated in the initial process of the start-up process, the fuel gas generated by the hydrogen generator 4 contains a large amount of carbon monoxide. When fuel gas having a relatively high carbon monoxide concentration is supplied to the fuel cell 2, the catalyst of the anode of the fuel cell 2 is poisoned. Therefore, during the starting process, the fuel gas generated by the hydrogen generator 4 is combusted by the combustor 4 a via the bypass flow path 9.

  When the selective oxidation catalyst of the selective oxidizer 3 reaches a temperature at which it can react, the control unit 20 sends an activation signal to the air blower 12 to supply the selective oxidizer gas to the selective oxidizer 3 to the selective oxidation air valve 18. An open signal is sent (step S202).

  As a result, the oxidant gas is supplied to the selective oxidizer 3, and the process proceeds to valve failure detection (steps S203 to S206) of the oxidant supply valve 16 and the oxidant discharge valve 17.

  As a valve failure detection of the oxidant supply valve 16 and the oxidant discharge valve 17, in step S203, the control unit 20 sends an open signal to the oxidant supply valve 16 and the oxidant discharge valve 17, and is measured by the cathode flowmeter 21. Check the amount of oxidant gas supplied.

  At this time, since the control unit 20 sends an open signal to the oxidant supply valve 16 and the oxidant discharge valve 17, the oxidant gas is supplied to the fuel cell 2 and flows through the oxidant gas supply channel 13. The supply of will increase. When the oxidant supply valve 16 and the oxidant discharge valve 17 are open and the control unit 20 is A (L / min) or more (Yes in step S204), the oxidant supply valve 16 or the oxidant discharge valve 17 is set. Is closed, the oxidant supply valve 16 and the oxidant discharge valve 17 are closed (step S105), and the confirmation of the close failure of the oxidant supply valve 16 and the oxidant discharge valve 17 is completed. The operation of the battery system 1 is stopped.

  If the supply amount of the oxidant gas flowing through the oxidant gas supply flow path measured by the cathode flow meter 21 is less than the predetermined value A (L / min) (No in step S204), the oxidant supply valve 16 and It is determined that the oxidant discharge valve 17 is not closed, the oxidant supply valve 16 and the oxidant discharge valve 17 are closed (step S206), the detection of the closed failure of these valves is terminated, and the hydrogen generator 4 When the time necessary for heating elapses or the hydrogen generator 4 reaches a predetermined temperature and the carbon monoxide in the fuel gas decreases, the next fuel gas supply step (step S207) is started.

  It should be noted that in the closing failure confirmation of the oxidant supply valve 16 and the oxidant discharge valve 17 described based on FIG. 4, it is confirmed that either the oxidant supply valve 16 or the oxidant discharge valve 17 is closed. When detected, it is preferable to prohibit the next activation of the fuel cell system 31 when an open failure is detected a plurality of times. In addition, it is more preferable to determine the abnormality only after determining a plurality of open failures and stop the operation of the fuel cell system 31.

The present invention is not limited to Embodiments 1 and 2 described above, and various design changes can be made within the scope of the technical idea of the present invention, and they all fall within the technical scope of the present invention. included. For example, the control unit 20 in the first and second embodiments is not only configured as a single control device, but also configured as a controller group in which a plurality of control units cooperate to execute control of the fuel cell system. It may be a form.

  The fuel cell system of the present invention is useful for, for example, a fuel cell system used for a cogeneration apparatus.

DESCRIPTION OF SYMBOLS 1, 31 Fuel cell system 2 Fuel cell 3 Selective oxidizer 4 Hydrogen generator (fuel gas supply part)
4a Combustor 5 Raw material blower 6 Raw material gas supply flow path 7 Fuel gas flow path 8 Exhaust gas flow path 9 Bypass flow path 10 Bypass valve 11 Anode inlet valve 12 Air blower (oxidant gas supply section)
DESCRIPTION OF SYMBOLS 13 Oxidant gas supply flow path 14 Oxidant gas discharge flow path 15 Selective oxidation air flow path 16 Oxidant supply valve 17 Oxidant discharge valve 18 Selective oxidation air valve 19 Selective oxidation flow meter 20 Control unit 21 Cathode flow meter

Claims (6)

A fuel cell system including a fuel cell that generates power using a fuel gas containing hydrogen and an oxidant gas containing oxygen,
A fuel gas supply unit for supplying the fuel gas to the fuel cell;
An oxidant gas supply unit for supplying the oxidant gas to the fuel cell;
An oxidant gas supply channel for supplying the oxidant gas from the oxidant gas supply unit to the fuel cell;
An oxidant gas discharge passage for discharging the oxidant gas from the fuel cell;
An oxidant gas branch channel branched from the oxidant gas supply channel;
Provided in at least one of the channel portion between the branch portion of the oxidant gas supply channel and the oxidant gas branch channel to the fuel cell, and the oxidant gas discharge channel. One or more selected valves,
An oxidant gas supply amount measuring unit that is provided in the oxidant gas branch flow channel and measures a branch supply amount of the oxidant gas supplied to the oxidant gas branch flow channel;
A control unit that controls at least the oxidant gas supply unit and the one or more valves, from the start of operation of the fuel cell system to the start of supply of the fuel gas to the fuel cell; The branch supply of the oxidant gas measured by the oxidant gas supply amount measurement unit when an activation signal is sent to the oxidant gas supply unit and an open signal is sent to all the one or more valves. A control unit that controls to continue operation of the fuel cell system when the amount is within a predetermined range;
A fuel cell system. The control unit controls the operation of the fuel cell system to stop when a branch supply amount of the oxidant gas measured by the oxidant gas supply amount measurement unit increases from a first specified value. ,
The fuel cell system according to claim 1. A supply capacity adjusting means for changing the supply capacity of the oxidant gas supply unit based on a branch supply amount of the oxidant gas measured by the oxidant gas supply amount measurement unit;
The control unit controls to stop the operation of the fuel cell system when the supply capacity of the oxidant gas supply unit decreases from a second specified value;
The fuel cell system according to claim 1. A selective oxidizer for removing carbon monoxide in the fuel gas;
The downstream end of the oxidant gas branch flow path has a configuration communicating with the selective oxidizer,
The fuel cell system according to any one of claims 1 to 3. A fuel cell system including a fuel cell that generates power using a fuel gas and an oxidant gas containing oxygen,
A fuel gas supply unit for supplying the fuel gas to the fuel cell;
An oxidant gas supply unit for supplying the oxidant gas to the fuel cell;
An oxidant gas supply channel for supplying the oxidant gas from the oxidant gas supply unit to the fuel cell;
An oxidant gas discharge passage for discharging the oxidant gas from the fuel cell;
An oxidant gas supply amount measuring unit which is provided in the oxidant gas supply channel or the oxidant gas discharge channel and measures the supply amount of the oxidant gas;
One or more valves provided in at least one of the oxidant gas supply channel and the oxidant gas discharge channel;
A control unit that controls at least the oxidant gas supply unit and the one or more valves, from the start of operation of the fuel cell system to the start of supply of the fuel gas to the fuel cell; The supply amount of the oxidant gas measured by the oxidant gas supply amount measurement unit when an activation signal is sent to the oxidant gas supply unit and an open signal is sent to all the one or more valves. A control unit that controls to continue the operation of the fuel cell system when is within a predetermined range;
A fuel cell system. The control unit controls to stop the operation of the fuel cell system when the supply amount of the oxidant gas measured by the oxidant gas supply amount measurement unit decreases from a third specified value;
The fuel cell system according to claim 5.