JP2009093966A - Fuel cell system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell system detecting whether an oxidation gas for air bleeding is properly supplied. <P>SOLUTION: The fuel cell system comprises: a reformer 1; a CO remover 2; an oxidation gas supplying unit 4 for supplying oxidation gas; a fuel cell 3 for generating power by using hydrogen-content gas supplied from the CO remover 2; a first oxidation gas passage 6 for mixing the oxidation gas supplied from the oxidation gas supplying unit 4 into hydrogen-containing gas supplied to the CO remover 2; a second oxidation gas passage 7 branched from the first oxidation gas passage 6 and mixing the oxidation gas into the hydrogen-containing gas fed from the CO remover 2; a flow rate measuring device 5 arranged on the first oxidation gas passage 6 at a downstream side rather than a branched section; a valve 8 arranged on the second oxidation gas passage 7 on a downstream side rather than the branched section; and a controller 9. The controller 9 stops an operation of the fuel cell system when a changed amount of a detected value of the flow rate measuring device 5 is smaller than a designated threshold when controlling the valve 8 so as to open the valve 8 during an operation of the oxidation gas supplying unit 4. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  TECHNICAL FIELD The present invention relates to a fuel cell system that generates power using a hydrogen-containing gas and an oxygen-containing gas, and in particular, generates a hydrogen-containing gas from a hydrocarbon-based raw material and water by a steam reforming reaction and uses it for power generation. The present invention relates to a fuel cell system.

  Conventionally, a fuel cell system capable of high-efficiency small-scale power generation is easy to build a system for using thermal energy generated during power generation. Development is progressing as a power generation system.

  In a fuel cell system, during a power generation operation, a hydrogen-containing gas and an oxidant gas are supplied to a fuel cell stack (hereinafter simply referred to as a fuel cell) disposed as a main body of the power generation unit. Then, in the fuel cell, a predetermined electrochemical reaction proceeds by using hydrogen contained in the supplied hydrogen-containing gas and oxygen contained in the oxidant gas. As the predetermined electrochemical reaction proceeds, chemical energy of hydrogen and oxygen is directly converted into electrical energy in the fuel cell. The fuel cell system outputs the electric energy generated in this way toward the load.

  By the way, the supply means of the hydrogen-containing gas necessary for the power generation operation of the fuel cell system is not usually provided as an infrastructure. Therefore, a conventional fuel cell system is usually provided with a reformer for generating a hydrogen-containing gas that is required during power generation operation.

  In this reformer, a hydrogen-containing gas is generated from a raw material such as a city gas containing an organic compound and water as a steam reforming reaction proceeds in the reforming catalyst. At this time, the reforming catalyst included in the reformer is heated to a temperature suitable for the progress of the steam reforming reaction by the heater. A heater heats the reforming catalyst which a reformer has, for example by burning the mixed gas of city gas and air. Thereby, in the reformer, a hydrogen-containing gas containing hydrogen is efficiently generated from the raw material such as city gas and water. The fuel cell system generates power using, for example, air as a hydrogen-containing gas and an oxygen-containing gas generated by the reformer.

  The hydrogen-containing gas produced from the reformer contains carbon monoxide, but the catalyst contained in the fuel cell is poisoned by the carbon monoxide, so that normal power generation in the fuel cell cannot be performed. . Therefore, in order to reduce the carbon monoxide concentration in the hydrogen-containing gas generated in the reformer, it is common to provide a shifter that performs a shift reaction and a CO remover that performs an oxidation reaction. Here, a CO remover will be described in particular.

  The hydrogen-containing gas is mixed with an oxidizing gas (for example, air) supplied from an oxidizing gas supplier, and an oxidation reaction is performed with an oxidation catalyst included in the CO remover, so that carbon monoxide contained in the hydrogen-containing gas is oxidized. It can be oxidized to carbon and the concentration of carbon monoxide can be reduced. However, the hydrogen-containing gas after passing through the CO remover still contains about 10 ppm of carbon monoxide. When the fuel cell is operated for a long period of time, the fuel cell is poisoned at this concentration level. Therefore, in order to further remove carbon monoxide, an oxidizing gas is supplied to the hydrogen-containing gas treated by the CO remover, and the carbon monoxide is oxidized and removed by the anode catalyst of the fuel cell (hereinafter referred to as this). Is called air bleed).

  When air bleed is performed, it is necessary to supply an oxidizing gas for air bleed between the CO remover and the fuel cell. For this purpose, an oxidizing gas supply device and a flow rate measuring device are required. However, if an oxidant gas supply device and a flow rate measuring device dedicated to air bleed are provided, the cost of the fuel cell system increases and the size of the apparatus increases.

  In view of this, a fuel cell system has been proposed in which an oxidizing gas supply device for air bleeding is shared with an oxidizing gas supply device for oxidizing air (see, for example, Patent Document 1). According to the configuration of the proposed fuel cell system, it is possible to reduce the number of parts, reduce the cost, and reduce the size of the apparatus. By performing air bleed, it becomes possible to prevent poisoning of the fuel cell due to carbon monoxide in the hydrogen-containing gas, and stable power generation in the fuel cell can be realized.

Furthermore, the flow meter is provided only in the path for supplying the oxidizing gas to the CO remover, and the oxidizing gas for the air bleed branches off the upstream of the flow meter for the CO remover. The amount of gas can be divided into optimum amounts. Thereby, the number of parts can be reduced, and cost reduction and downsizing of the apparatus can be realized.
JP 2005-190995 A

  However, in this proposed fuel cell system, when the valve provided in the air bleed path is opened and air bleed is to be performed, the valve is stuck and does not open, or water is in the piping of the air bleed path. There is a problem that the air bleed oxidizing gas cannot be normally sent due to condensation or clogging, and the fuel cell is deteriorated.

  Note that the air bleed path valve is used when supplying the oxidizing gas only to the CO remover at the time of starting the fuel cell system, or when the oxidizing gas supplier is not supplying the oxidizing gas during the starting operation of the fuel cell system. This is necessary to prevent clogging caused by the backflow of gas containing water vapor flowing through the CO remover to the air bleed path, and cannot be deleted.

  In view of the above-described problems of the conventional fuel cell system, the present invention can detect that the oxidizing gas for air bleed is not normally supplied and suppress the progress of deterioration of the fuel cell. An object is to provide a fuel cell system.

In order to achieve the above object, the first present invention provides:
A reformer that generates hydrogen-containing gas using raw materials;
A CO remover for reducing carbon monoxide in the hydrogen-containing gas by an oxidation reaction;
An oxidizing gas supply for supplying oxidizing gas;
A fuel cell that generates electricity using the hydrogen-containing gas delivered from the CO remover;
A first oxidizing gas flow path for mixing the oxidizing gas supplied from the oxidizing gas supplier into the hydrogen-containing gas supplied to the CO remover;
A second oxidizing gas channel for branching from the first oxidizing gas channel and mixing the oxidizing gas into the hydrogen-containing gas delivered from the CO remover;
A flow rate measuring device provided in the first oxidizing gas flow path downstream from the branching portion;
A valve provided in the second oxidizing gas flow path downstream from the branch part;
With a controller,
The controller is a fuel cell system characterized in that the operation is stopped based on a detected value of the flow rate measuring device when the valve is controlled to open during operation of the oxidizing gas supply device.

The second aspect of the present invention is
The controller is configured to stop the operation when the amount of change in the detected value of the flow rate measuring device is larger than a predetermined threshold when the valve is opened during the operation of the oxidizing gas supply device. 1 is a fuel cell system according to a first aspect of the present invention.

The third aspect of the present invention
The controller controls the operating amount of the oxidant gas supply device to be constant and operates when the amount of change in the detected value of the flow meter when the valve is controlled to open is larger than a predetermined threshold value. Is a fuel cell system according to the second aspect of the present invention.

The fourth aspect of the present invention is
The controller controls to increase the operation amount of the oxidizing gas supply device, and when the change amount of the detection value of the flow rate measuring device when controlling to open the valve is larger than a predetermined threshold, The fuel cell system according to the second aspect of the present invention is characterized in that the operation is stopped.

The fifth aspect of the present invention is
If the amount of change in the value detected by the flow meter when the controller controls to open the valve during the operation of the oxidizing gas supply device is larger than a predetermined threshold value, an error is indicated. A fuel cell system according to a second aspect of the present invention is provided with an abnormality alarm device for reporting.

The sixth aspect of the present invention
During the operation of the oxidizing gas supply device, the controller continues more than once that the amount of change in the value detected by the flow meter when the valve is controlled to open is greater than a predetermined threshold value. In this case, the fuel cell system according to the second aspect of the present invention is characterized in that the operation is stopped.

The seventh aspect of the present invention
A reformer that generates hydrogen-containing gas using raw materials;
A CO remover for reducing carbon monoxide in the hydrogen-containing gas by an oxidation reaction;
An oxidizing gas supply for supplying oxidizing gas;
A fuel cell that generates power using the hydrogen-containing gas delivered from the CO remover;
A first oxidizing gas flow path for mixing the oxidizing gas supplied from the oxidizing gas supplier into the hydrogen-containing gas supplied to the CO remover;
A second oxidizing gas flow path for branching from the first oxidizing gas flow path and mixing the oxidizing gas into the hydrogen-containing gas delivered from the CO remover;
A flow rate measuring device provided in the first oxidizing gas flow path downstream from the branching portion;
A valve provided in the second oxidizing gas flow path downstream from the branch part;
With a controller,
The controller operates the oxidizing gas supply when controlling the opening of the valve while controlling the operation amount of the oxidizing gas supply so that the value detected by the flow measuring device becomes a predetermined value. The fuel cell system is characterized in that the operation is stopped when the amount of increase is smaller than a predetermined threshold.

Further, the eighth aspect of the present invention is
The controller controls the operating amount of the oxidizing gas supplier so that the value detected by the flow meter is maintained at a predetermined value, and controls the oxidizing gas supplier to open the valve. The fuel cell system according to the seventh aspect of the present invention is characterized in that the operation is stopped when the increase amount of the manipulated variable is smaller than a predetermined threshold value.

The ninth aspect of the present invention provides
The controller controls the operating amount of the oxidizing gas supplier so that the value detected by the flow meter increases by a predetermined amount, and operates the oxidizing gas supplier when controlling the valve to open. The fuel cell system according to the seventh aspect of the present invention is characterized in that the operation is stopped when the amount of increase is smaller than a predetermined threshold value.

The tenth aspect of the present invention is
The oxidizing gas supply device when the controller controls to open the valve while controlling the operation amount of the oxidizing gas supply device so that the value detected by the flow rate measuring device is maintained at a predetermined value. A fuel cell system according to a seventh aspect of the present invention is provided with an abnormality notifier for notifying that an abnormality has occurred when the amount of increase in the control command value of the manipulated variable is smaller than a predetermined threshold value.

The eleventh aspect of the present invention is
The controller is configured to control the oxidant gas supply unit to open the valve while controlling the operation amount of the oxidant gas supply unit so that the value detected by the flow rate measuring device is maintained at a predetermined value. The fuel cell system according to the seventh aspect of the present invention is characterized in that the operation is stopped when the increase amount of the manipulated variable is smaller than a predetermined threshold value for a plurality of times.

  ADVANTAGE OF THE INVENTION According to this invention, the fuel cell system which can detect that the oxidizing gas for air bleeding is not supplied normally, and can suppress progress of deterioration of a fuel cell can be provided.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, the best mode for carrying out the invention will be described in detail with reference to the drawings.

(Embodiment 1)
First, the configuration of the fuel cell system according to Embodiment 1 of the present invention and the basic operation at the start of supplying the air bleed oxidizing gas will be described with reference to FIG.

  FIG. 1 is a block diagram schematically showing the configuration of the fuel cell system according to Embodiment 1 of the present invention. In FIG. 1, only the components necessary for explaining the present invention are shown, and the other components are not shown.

  The reformer 1 of FIG. 1 is a device that generates a hydrogen-containing gas from a raw material containing an organic compound composed of at least carbon and hydrogen, such as city gas, LPG, and kerosene, and water, and advances a steam reforming reaction. A temperature sensor for detecting the temperature of the reforming catalyst and the reforming catalyst is provided. As the temperature sensor, a thermocouple is used in this embodiment, but any sensor may be used as long as it can detect the temperature. Further, the water may be heated outside the reformer 1 and supplied as water vapor, but in this embodiment, a water evaporation unit is provided in the reformer 1. Further, a water supplier 16 for supplying water to the reformer 1 and a raw material supplier 17 for supplying raw materials are provided.

  Further, the steam reforming reaction is an endothermic reaction, and it is necessary to apply heat to advance the reaction. Therefore, the reformer 1 has a heater 1a, which heats the reforming catalyst. In the present embodiment, a combustion burner is used as the heater, and a raw material that has passed through the reformer 1 and an anode off-gas discharged from the anode of the fuel cell 3 are used as the fuel. In addition, if it can heat, it does not need to be a combustion burner.

  The CO remover 2 is a device for reducing carbon monoxide in the hydrogen-containing gas produced by the reformer 1, and is connected to the reformer 1 by a hydrogen-containing gas flow path 10. Carbon monoxide is reduced by reacting carbon monoxide with oxygen in the oxidizing gas by the oxidation catalyst provided in the CO remover 2 to change it to carbon dioxide. This oxidizing gas is supplied by an oxidizing gas supplier 4. In the present embodiment, air is used as an example of the oxidizing gas. Moreover, although the air pump was used as the oxidizing gas supply device 4, any configuration may be used as long as the oxidizing gas can be supplied.

  The fuel cell 3 is a device that generates electric power using supplied hydrogen-containing gas and oxidizing gas, and is connected to the CO remover 2 by a hydrogen-containing gas flow path 10. Although not shown, the fuel cell 3 has a path for supplying an oxidant gas, and air is supplied as an oxidant gas by a blower or the like. Further, during the start-up operation of the fuel cell system, the hydrogen-containing gas is not supplied to the fuel cell 3 because the carbon monoxide concentration in the hydrogen-containing gas after passing through the reformer 1 and the CO remover 2 is high. Control is performed so that the hydrogen-containing gas is supplied to the heater 1 a of the reformer 1 through the bypass path 15 that bypasses the fuel cell 3. Thus, the heat required for the steam reforming reaction is provided by burning in the heater 1a.

  Then, when the reformer 1 and the CO remover 2 are sufficiently warmed to generate a hydrogen-containing gas with a sufficiently reduced carbon monoxide concentration, the fuel cell 3 starts to be supplied with the hydrogen-containing gas, Power is generated by reacting with oxidant gas. At this time, not all hydrogen in the hydrogen-containing gas is used for power generation in the fuel cell 3. Therefore, the hydrogen-containing gas containing surplus hydrogen is supplied to the heater 1a of the reformer 1 through the anode off-gas passage 19 as the anode off-gas discharged from the fuel cell 3, and used as energy for heating the reforming catalyst. Thus, it is possible to effectively use energy and realize efficient power generation. Further, when power is generated by the fuel cell 3, electricity and heat are generated. In order to effectively use this heat, heat is recovered by flowing water and exchanging heat with a heat medium such as water. Although not shown, the heat medium (for example, hot water) recovered in this way is stored in a hot water storage tank or the like and used as hot water.

  The bypass path 15 is disposed so as to connect the hydrogen-containing gas flow path 10 between the CO remover 2 and the fuel cell 3 and the anode off-gas path 19 that connects the fuel cell 3 and the heater 1a. . A flow path switch 18 is provided at a branch point from the hydrogen-containing gas flow path 10 to the bypass path 15. By this flow path switch 18, the supply destination of the hydrogen-containing gas after passing through the CO remover 2 is switched to the bypass path 15 side or the fuel cell 3 side.

  In order to supply the oxidizing gas supplied from the oxidizing gas supplier 4 to the CO remover 2, a first oxidizing gas flow connecting the oxidizing gas supplier 4 and the hydrogen-containing gas flow path 10 upstream of the CO remover 2. A path 6 is provided. The oxidizing gas supplied to the CO remover 2 is mixed with the hydrogen-containing gas generated in the reformer 1 and used in the CO remover 2 to reduce carbon monoxide. Further, a valve 13 is provided in the first oxidizing gas flow path 6 so that the oxidizing gas can be supplied to and stopped from the CO remover 2.

  In this embodiment, the oxidizing gas flow path 6 is connected to the upstream side of the CO remover 2. However, if it can be mixed with the hydrogen-containing gas generated by the reformer 1, the oxidizing gas flow path 6 is directly oxidized to the CO remover 2. You may comprise so that gas may be supplied.

  A flow rate measuring device 5 is provided in the first oxidizing gas flow path 6. The flow rate measuring device 5 measures the amount of oxidizing gas supplied to the CO remover 2, and the controller 9 controls the oxidizing gas supply device 4 so as to obtain a predetermined amount of oxidizing gas. Here, when the amount of the oxidizing gas supplied to the CO remover 2 is too large, not only carbon monoxide in the hydrogen-containing gas but also hydrogen gas is consumed, and the hydrogen-containing gas cannot be generated efficiently. . On the other hand, if the amount of the oxidizing gas is too small, carbon monoxide in the hydrogen-containing gas cannot be sufficiently reduced, which affects the power generation in the fuel cell 3.

  Further, a second branch is formed at the branch portion 14 of the first oxidizing gas flow path 6 between the oxidizing gas supply device 4 and the flow rate measuring device 5 and joins the hydrogen-containing gas flow path 10 downstream of the CO remover 2. The oxidizing gas flow path 7 is provided. The flow of the oxidizing gas supplied from the oxidizing gas supply device 4 includes a first oxidizing gas channel 6 for supplying the oxidizing gas from the oxidizing gas supply device 4 to the CO remover 2 at the branching section 14, and the oxidizing gas supply device 4. To a second oxidizing gas flow path 7 for supplying an oxidizing gas to the downstream side of the CO remover 2.

  The oxidizing gas that has passed through the second oxidizing gas flow path 7 is supplied downstream of the CO remover 2 and is not oxidized by the CO remover 2, but a trace amount of carbon monoxide in the hydrogen-containing gas that has passed through the CO remover 2. It is used to reduce the amount by oxidation reaction. In the present embodiment, the carbon monoxide concentration in the hydrogen-containing gas that has passed through the CO remover 2 is approximately 10 ppm. Even if this slight carbon monoxide concentration is used, the influence of poisoning appears when the fuel cell 3 is operated for a long period of time. Therefore, it is necessary to remove carbon monoxide adsorbed in the anode catalyst of the fuel cell 3, and carbon monoxide is removed by oxidizing the oxidizing gas and carbon monoxide adsorbed on the anode catalyst of the fuel cell 3. The

  Note that a gas flow meter such as the flow rate measuring device 5 is not used for the second oxidizing gas flow path 7, and the flow pressure loss of the first oxidizing gas flow path 6 and the second oxidizing gas flow path 7. Therefore, the oxidizing gas sent by the oxidizing gas supply device 4 is designed to be diverted at a predetermined ratio. Then, by adjusting the amount of oxidant gas supplied from the oxidant gas supply unit 4 based on the oxidant gas flow rate measured by the flow rate measuring device 5, the oxidant gas flow rate through the second oxidant gas channel 7 is also desired. It can be an amount. In addition, by designing in this way, it is not necessary to install a gas flow meter on the second oxidizing gas flow path 7, thereby reducing the cost and realizing a reduction in the size of the apparatus. In this design, the amount of oxidizing gas supplied from the first oxidizing gas path 6 to the CO remover 2 and the hydrogen-containing gas flow path 10 downstream from the second oxidizing gas path 7 to the CO remover 2 are designed. The amount of oxidant gas supplied is controlled proportionally with respect to the concentration of carbon monoxide in the hydrogen-containing gas supplied to the CO remover 2 without individually controlling the flow rate. This is based on the achievement of the reduction objective.

  The second oxidizing gas channel 7 is provided with a valve 8, and the second oxidizing gas channel 7 can be opened and closed by the valve 8. When the fuel cell system is started, the CO remover 2 is not sufficiently warmed, so that the carbon monoxide in the hydrogen-containing gas cannot be sufficiently reduced, so that the hydrogen-containing gas is not supplied to the fuel cell 3 and the bypass path The hydrogen-containing gas is supplied to the heater 1 a by bypassing the fuel cell 3 via 15. For this reason, the valve 8 is closed and the second oxidizing gas flow path 7 is closed, and the oxidizing gas is supplied only to the CO remover 2.

  In addition, the hydrogen-containing gas after passing through the reformer 1 contains a large amount of carbon monoxide while the temperature of the fuel cell system (particularly the reformer 1) is raised at the time of startup. . If the oxidizing gas is supplied to the CO remover 2 in this state, the oxidation catalyst of the CO remover 2 may be overheated, and the oxidizing gas supply unit 4 may be stopped. At this time, the hydrogen-containing gas containing a large amount of carbon monoxide may flow backward through the second oxidizing gas flow path 7 and eventually be released to the atmosphere via the oxidizing gas supply device 4. The oxidizing gas flow path 7 is closed in conjunction with the oxidizing gas supply device 4 by a valve 8. In this case, the valve 13 of the first oxidizing gas channel 6 is also closed. Further, it is necessary to close the valve 8 and the valve 13 so that the combustible gas contained in the system does not leak outside the system through the oxidizing gas supply device 4 at the time of stop and standby. For the reasons described above, the valve 8 is necessary and cannot be removed.

  The controller 9 is configured to supply the oxidizing gas flow rate measured by the flow rate measuring device 5 to the target flow rate of the oxidizing gas corresponding to the current operating state (for example, the power generation amount of the fuel cell 3). 4 is a device that increases or decreases the operation amount. Further, the controller 9 detects an abnormality of the valve 8 based on the detected value of the flow rate measuring device 5, the operation amount of the oxidizing gas supply device 4, or the control command value of the operation amount to the oxidizing gas supply device 4, Control to stop the fuel cell system is also performed. In the present embodiment, the configuration of the controller 9 is a calculation device such as a microcomputer, and has a calculation unit (not shown) including a CPU or the like. The controller 9 may have any configuration as long as it can perform a predetermined operation.

  In addition, when the controller 9 detects an abnormality that the oxidizing gas cannot be normally supplied to the hydrogen-containing gas flow path 10, an abnormality alarm 12 is provided to notify the user or the maintenance company that an abnormality has occurred. It has been.

  Next, a basic start-up operation until the fuel cell system according to Embodiment 1 of the present invention starts supplying the air bleed oxidizing gas will be described. FIG. 2 is a diagram showing a control flow of the fuel cell system according to the first embodiment.

  In the start-up operation of the fuel cell system, the controller 9 is suitable for first heating the reformer 1 with the heater 1a and generating the hydrogen-containing gas as shown in S1 of FIG. Increase to temperature. Specifically, in order to heat the reformer 1, the controller 9 starts supplying the reformer 1 from the raw material supplier 17. And after the raw material which distribute | circulated the inside of the reformer 1 with the flow path switch 18 passes the bypass path 15 which bypasses the fuel cell 3, it is supplied to the heater 1a and combusted. The reason why the raw material is passed through the reformer 1 is that the raw material is used as a heating medium for heating the reformer 1 and the CO remover 2 from the inside, and the raw material is supplied directly to the heater without passing through the reformer 1. It doesn't matter.

  Next, steam is supplied to the reformer 1, but when the raw material contained in the reformer 1 is heated to a predetermined temperature or higher without water, the carbon component in the raw material is precipitated and reformed. Since the flow path of the reformer 1 is clogged or the reforming catalyst is deteriorated, supply of steam to the reformer 1 is started when the temperature of the reformer 1 is lower than the upper limit temperature at which carbon in the raw material does not precipitate. In the fuel cell system of the present embodiment, control is performed by the controller 9 so that water is supplied from the water supplier 16 to the reformer 1 below the upper limit temperature (S2).

  Moreover, in this Embodiment, since water is made into water vapor | steam with the heat | fever of the heater 1a, when supply of water is started from the water supply device 16, it will be the temperature which a water evaporation part can evaporate water. The heat from the heater 1a is distributed to the. In this embodiment, the temperature of the reformer 1 that starts supplying water to the reformer 1 from the water supplier 16 is set to 400 ° C., but the temperature at which water can be evaporated below the upper limit temperature at which carbon does not precipitate. Any temperature can be used. Further, this temperature varies depending on the configuration of the reformer 1 and the mounting position of the temperature detection means.

  When the raw material and steam are supplied to the reformer 1 in this way, hydrogen-containing gas begins to be generated by the steam reforming reaction. The steam reforming reaction is an endothermic reaction, and the generated hydrogen concentration and carbon monoxide concentration vary depending on the temperature of the reforming catalyst. Then, the controller 9 opens the valve 13 after the temperature in the reformer 1 is sufficiently warmed and the hydrogen concentration in the hydrogen-containing gas starts to increase, and operates the oxidizing gas supply device 4 to The oxidizing gas is supplied to the CO remover 2 via the oxidizing gas channel 6 (S3).

  On the other hand, since the oxidation reaction performed in the CO remover 2 is also an equilibrium reaction, the CO remover 2 is heated by a heater or the like to a temperature necessary for proceeding with the reaction. Note that, depending on the configuration of the CO remover 2, it is possible to heat using the heat held by the gas sent from the reformer 1, and there is no need for heating means such as a heater. Although the concentration of carbon monoxide is reduced by the CO remover 2, when the oxidizing gas has just begun to be supplied to the CO remover 2, the temperature of the oxidation catalyst has not been heated uniformly, The carbon monoxide concentration in the hydrogen-containing gas after passing through the CO remover 2 has not yet been sufficiently reduced for reasons such as not being sufficiently warmed yet and high concentration carbon monoxide being sent. Therefore, after both the reformer 1 and the CO remover 2 rise to their optimum reaction temperatures, the flow path switch 18 is switched from the bypass path 15 side to the fuel cell 3 side, and the hydrogen-containing gas is supplied to the fuel cell 3. Will be started.

  Even after the CO remover 2 has risen to the reaction temperature, the hydrogen-containing gas after passing through the CO remover 2 contains about 10 ppm of carbon monoxide. In order to suppress poisoning, it is necessary to supply the oxidizing gas to the hydrogen-containing gas after passing through the CO remover 2 from the second oxidizing gas channel 7.

  The timing for starting the supply of the oxidizing gas from the second oxidizing gas flow path 7 is that the supply of the hydrogen-containing gas to the fuel cell 3 is started after the supply of the oxidizing gas from the first oxidizing gas flow path 6 is started. The timing is just before the start, as long as it can sufficiently reduce the concentration of carbon monoxide in the hydrogen-containing gas supplied to the fuel cell 3. In the present embodiment, after the supply of the oxidizing gas from the first oxidizing gas channel 6 is started, the supply is started after the flow rate of the oxidizing gas is stabilized. The stabilization time is 1 minute, but this is not limited because the time varies depending on the apparatus configuration.

  The supply of the oxidizing gas from the second oxidizing gas channel 7 is performed by the control signal of the controller 9 in the state where the oxidizing gas is supplied from the oxidizing gas supplier 4 to the first oxidizing gas channel 6. Is started from the closed state to the open state. The resistance of each channel is designed so that the distribution ratio of the amount of the oxidizing gas flowing through the first oxidizing gas channel 6 and the second oxidizing gas channel 7 is about 4.5: 1. This distribution ratio is realized in a state in which the valve 8 and the valve 13 are completely opened and the first oxidizing gas channel 6 and the second oxidizing gas channel 7 are not clogged with condensed water. . The distribution ratio of the oxidizing gas amount needs to be changed depending on the amount of carbon monoxide in the hydrogen-containing gas after passing through the CO remover 2 and the poisoning resistance of the fuel cell. Therefore, the distribution ratio of the oxidizing gas is not limited to the above ratio, and may be a ratio suitable for each apparatus configuration.

  In terms of the accuracy of flow control, the CO concentration in the hydrogen-containing gas is normally reliably reduced to a desired concentration by the CO remover 2, and the remaining trace amount (usually about 10 ppm) is due to the carbon monoxide. Since the anode catalyst poisoning is designed to be suppressed by air bleed, the oxidizing gas supplied to the first oxidizing gas channel 6 is more targeted than the oxidizing gas supplied from the second oxidizing gas channel 7. The tolerance of error with respect to the flow rate is small. For example, in the present embodiment, the error range allowed for the first oxidizing gas flow path 6 is ± 10%, whereas the error range allowed for the second oxidizing gas flow path 7 is ± 30%. . For that reason, it is desirable to install the flow rate measuring device 5 in the first oxidizing gas flow path 6 that requires stricter flow rate control. The allowable error range varies depending on the apparatus configuration, design margin, and the like, and is not limited to this range.

  Next, a method for detecting whether or not air bleed is normally performed will be described.

  As described above, the oxidant gas is supplied to the downstream side of the CO remover 2 by opening the valve 8. However, when the valve 8 does not operate normally and is not completely opened, or when the second is caused by condensed water or the like. When the oxidizing gas flow path 7 is clogged, a predetermined amount of oxidizing gas cannot be supplied from the second oxidizing gas flow path 7, and air bleed cannot be performed normally. Therefore, in order to perform air bleed normally and suppress the deterioration of the fuel cell 3, a predetermined amount of oxidizing gas is supplied when the oxidizing gas is supplied from the second oxidizing gas flow path 7. It is necessary to check whether or not.

  In the fuel cell system according to the present embodiment, the flow rate measuring device 5 detects when the controller 9 issues an opening command to the valve 8 to start air bleed while keeping the operation amount of the oxidizing gas supply device 4 constant. Abnormality detection of air bleed operation is performed based on the value.

  In a state in which the valve 8 is closed, if the operation amount of the oxidizing gas supply device 4 is controlled to be constant, the flow rate value measured by the flow rate measuring device 5 becomes substantially constant. From this state, when the valve 8 is opened while the operating amount of the oxidizing gas supply device 4 is kept constant, the oxidizing gas sent with the same capacity is branched and the first oxidizing gas channel 6 and the second oxidizing gas are branched. Since it flows in the flow path 7, the oxidizing gas which flows into the flow measuring device 5 decreases.

  However, if the valve 8 does not operate normally and the controller 9 remains open even when the opening command is issued, or if the second oxidizing gas flow path 7 is clogged, the flow rate measuring device 5 The amount of oxidant gas flowing through the first oxidant gas does not change, or the amount of decrease in the flow rate of oxidant gas flowing through the first oxidant gas path 6 is smaller than an assumed value. As described above, when the controller 9 issues an opening command for changing the valve 8 from the closed state to the open state in order to start the air bleed, the oxidizing gas normally flows through the second oxidizing gas channel 7. The amount of change in the flow rate detected by the flow rate measuring device 5 differs depending on whether or not it is.

  In the present embodiment, whether or not air bleed is normally performed is detected based on the detection value detected by the flow rate measuring device 5.

  In S3 shown in FIG. 2, after the valve 13 is opened and the oxidizing gas is supplied through the first oxidizing gas channel 6, the flow rate A (before the opening command to the valve 8) is maintained in a state where the flow rate of the oxidizing gas is stable. Is detected by the flow rate detector 5 (see S6 in FIG. 2).

  Next, after measuring the flow rate A, the controller 9 issues an opening command to the valve 8 (S7).

  Subsequently, the flow rate B after the opening command is issued to the valve 8 is measured by the flow rate measuring device 5 (S6).

  Here, in the present embodiment, the change amount of the flow rate of the oxidizing gas detected by the flow rate measuring device 5 is defined as the following formula (1) as the “change amount of the detected value of the flow rate measuring device” of the present invention. Is done. The change amount X is not an absolute value but a relative value having a positive or negative value.

Change X = flow rate B after opening command for valve 8−flow rate A before opening command for valve 8 (Equation 1)

Next, the controller 9 calculates the change amount X from the flow rate A and the flow rate B in S7. In step S8, the amount of change X is compared with a preset threshold value Z. If the amount of change X is larger than the threshold value Z, that is, if the expression (2) is satisfied, the air bleed is normal. It is determined that it cannot be implemented.

Change amount X> threshold value Z (Expression 2)

Further, the amount of change when no oxidizing gas flows through the second oxidizing gas flow path 7 as in the case where the valve 8 does not operate at all or the second oxidizing gas flow path 7 is completely clogged. Is set to Xo, the valve 13 is completely opened, and the first oxidizing gas channel 6 and the second oxidizing gas channel 7 are not clogged with condensed water or the like (the oxidizing gas has the above-mentioned distribution ratio). Assuming that the amount of change in the flowing state is Xp, the threshold value Z can be set to the center value of Xo and Xp, for example. The threshold value varies depending on the device configuration and the way of branching of the oxidizing gas. Therefore, the threshold value is not limited to this value, and is set according to the amount of oxidizing gas supplied from the oxidizing gas supplier 4. Any value may be used as long as an oxidizing gas amount equal to or higher than a predetermined threshold value capable of realizing air bleed that does not deteriorate the catalyst performance of the fuel cell 3 is supplied. Therefore, even when the valve 8 is not completely opened, when the change amount X is equal to or less than the threshold value Z, it is determined to be normal. In the above description, the predetermined threshold value is set according to the amount of oxidizing gas supplied from the oxidizing gas supply device 4, but is not limited thereto. It may be set according to the value of each parameter proportional to the supply amount of the oxidizing gas from the oxidizing gas supply device 4 such as the raw material supply amount to the mass device 1.

  Hereinafter, the determination will be described using specific numerical values as examples.

  Assuming that the operating amount of the oxidizing gas from the oxidizing gas supply unit 4 is 1.65 (NL / min), the first oxidizing gas flow path 6 is opened after the valve 13 is opened and before the valve 8 is opened. The flow rate A of the oxidizing gas flowing inside is also 1.65 (NL / min).

  On the other hand, when the opening command is issued to the valve 8 and the valve 8 is completely opened and the second oxidizing gas passage 7 is not clogged, the first oxidizing gas passage 6 and the second oxidizing gas Since the distribution ratio of the gas flow path 7 is 4.5: 1, the flow rate B of the oxidizing gas flowing in the first oxidizing gas flow path 6 is 1.35 (NL / min), and the second oxidizing gas flow The flow rate of the oxidizing gas flowing through the passage 7 is 0.3 (NL / min). Therefore, after the opening command to the valve 8, the flow rate measuring device 5 detects a value of 1.35 (NL / min).

  Therefore, when the valve 8 is completely opened and the second oxidizing gas flow path 7 is not clogged, the change amount Xp is −0.3 (= 1.35−1.65).

  On the other hand, for example, when the valve 8 fails and does not operate at all, or when the second oxidizing gas channel 7 is completely clogged, the oxidizing gas does not flow through the second oxidizing gas channel 7 at all. The flow rate B of the oxidizing gas channel is 1.65 (NL / min), and the change amount Xo is 0 (= 1.65 to 1.65).

  Therefore, when the threshold value Z is set to, for example, -0.15, the controller 9 normally performs the air bleed when the change amount X calculated by (Equation 1) is larger than the threshold value Z, -0.15. It can be determined that is not implemented.

  By such control, air is generated when the valve 8 is not opened even when an opening command is sent from the controller 9 to the valve 8, or when the second oxidizing gas channel 7 is clogged with water or the like. It is possible to detect a bleed operation abnormality.

  As shown in S9 of FIG. 2, when it is determined that the air bleed is normally performed, the hydrogen-containing gas that has passed through the CO remover 2 is supplied to the fuel cell 3 and power generation is started. However, when it is determined that the fuel cell system is not normally implemented, the following control is performed as the fuel cell system. As one response, operation is stopped. This is because if the operation is continued as it is, the anode catalyst of the fuel cell 3 may be poisoned.

  Further, as another measure, an abnormality is notified by the abnormality notifier 12 (S10). As an abnormality notification destination, notify a user who is using the device by notifying an operation remote controller (not shown) of the fuel cell system, or notifying a company that performs maintenance of the fuel cell system, etc. Therefore, there is a method for prompting the user, a maintenance company, etc. to appropriately deal with the abnormality of the fuel cell system. For example, if the user is a user, the user can press the stop button of the fuel cell system to stop the system or contact the maintenance company. This means that a stop signal is output to the fuel cell system in which an abnormality has been notified through, or the maintenance man is heading for the maintenance of the fuel cell system in which the abnormality has been notified.

  Further, when an abnormality is detected, the valve 8 may be opened and closed several times without immediately determining the abnormality, and if the abnormality is still not resolved, the abnormality may be confirmed and the operation may be stopped. Further, the abnormality may be notified when the operation stop due to the abnormality occurs several times. Moreover, when abnormality is detected, while stopping driving | operation as mentioned above, abnormality may be alert | reported and either one may be sufficient.

  As described above, since it is confirmed that the air bleed is operating normally, the fuel cell can be operated while reliably supplying the oxidizing gas for the air bleed. Thus, it is possible to provide a fuel cell system that can be suitably operated for a longer period of time.

  In the present embodiment, the method for checking the operation of the valve 8 while controlling the operation amount of the oxidizing gas supply device 4 to a constant value has been described. However, even if the control value is not controlled to a constant value, the valve 8 If the amount of change in the flow rate measured by the flow rate measuring device 5 does not reach a predetermined value due to opening and closing, the valve 8 may be determined to be abnormal.

  For example, the control may be performed so as to increase the operation amount of the oxidizing gas supply device 4. Hereinafter, the case of controlling to increase will be described by taking specific numerical values as examples.

(Example 1 of operation amount increase control)
Hereinafter, as an explanation example 1 of the operation amount increase control, the supply amount (flow rate A) of the oxidizing gas in the state where the valve 8 is closed is set to 1.65 (NL / min), and the controller 9 together with the opening command of the valve 8 An example will be described in which the amount of operation of the oxidizing gas supply device 4 is controlled to increase so that the oxidizing gas supply amount increases to 2.2 (NL / min).

  In this case, in the state where the valve 8 is normally opened after the operating amount of the oxidizing gas supply device 4 is increased and the second oxidizing gas flow path 7 is not clogged, the increased supply amount 2.2 (NL / min) is distributed, and the flow rate B of the oxidizing gas flowing through the first oxidizing gas channel 6 is 1.8 (NL / min), and the flow rate of the oxidizing gas flowing through the second oxidizing gas channel 7 is 0.4 (NL / min). Accordingly, the controller 9 calculates the change amount Xp as +0.15 (1.8-1.65).

  On the other hand, if the valve 8 fails or the second oxidizing gas channel 7 is clogged with water, and no oxidizing gas flows into the second oxidizing gas channel 7, the first oxidizing gas flow The flow rate B of the oxidizing gas flowing through the path 6 is 2.2 (NL / min). Therefore, the change amount Xo is +0.55 (2.2-1.65).

  Therefore, for example, if the threshold value is set to +0.35, if the change amount calculated by (Equation 1) by the controller 9 is larger than the threshold value Z which is +0.35, it is determined that the valve 8 is out of order. The

  Even when the operation amount of the oxidant gas supply device 4 is controlled to increase as described above, even when the oxidant gas operation amount is controlled to be kept constant as in the embodiment, the change occurs. As shown in (Equation 1), the amount of change calculated from the value detected by the flow rate measuring device 5 is less than a predetermined threshold value by providing a distinction between positive and negative values as relative values instead of absolute values. If it is larger, it can be determined that the air bleed is not normally performed.

(Example 2 of operation amount increase control)
Further, as an example 2 of the increase control, as an example in which the operation amount of the oxidizing gas supply device 4 is changed, the supply amount (flow rate A) of the oxidizing gas when the valve 8 is closed is 1.65 (NL / Min), and the controller 9 increases the operation amount of the oxidant gas supply unit 4 so that the oxidant gas supply amount increases to 1.76 (NL / min) together with the opening command of the valve 8.

  In this case, after the operating amount of the oxidizing gas supply device 4 is increased, the increased supply amount 1.76 (NL / in) when the valve 8 is completely opened and the second oxidizing gas channel 7 is not clogged. min) is distributed to the two flow paths, and the flow rate B of the oxidizing gas flowing in the first oxidizing gas flow path 6 is 1.44 (NL / min), and flows in the second oxidizing gas flow path 7. The flow rate of the oxidizing gas is 0.32 (NL / min). Accordingly, the controller 9 calculates the change amount Xp as −0.21 (1.44 to 1.65).

  On the other hand, when no oxidizing gas flows through the second oxidizing gas flow path 7, the flow rate B of the oxidizing gas flowing through the first oxidizing gas flow path 6 is 1.76 (NL / min). Therefore, the change amount Xo is +0.11 (1.76-1.65).

  Therefore, for example, if the threshold value is set to −0.05, the air bleed is normally performed when the change amount X calculated by the controller 9 using the equation (1) is larger than the threshold value Z −0.05. It is determined that it is not.

  As described above, the amount of change may be a negative value depending on the degree of increase in the amount of operation of the oxidizing gas supply device 4, but in the same way as when the amount of increase is a positive value, When the amount of change calculated from the detected value is larger than a predetermined threshold value, it can be determined that the air bleed is not normally performed.

  Further, the control of the oxidizing gas supply unit 4 may be performed so as to reduce the operation amount of the oxidizing gas supply unit 4. Hereinafter, the case where control is performed so as to reduce the operation amount of the oxidizing gas will be described with specific numerical values.

(Example of manipulated variable reduction control)
The supply amount (flow rate A) of the oxidizing gas when the valve 8 is closed is set to 1.65 (NL / min), and the controller 9 sets the oxidizing gas supply amount to 1.10 (NL / min) together with the opening command of the valve 8. The case where the operation amount of the oxidizing gas supply device 4 is reduced so as to reduce the amount of the gas will be described as an example.

  In this case, the flow rate of the oxidizing gas flowing through the first oxidizing gas channel 6 in a state where the valve 8 is normally opened and the second oxidizing gas channel 7 is not clogged after the reduction of the oxidizing gas supply amount. B is 0.9 (NL / min), and the flow rate of the oxidizing gas flowing in the second oxidizing gas flow path 7 is 0.2 (NL / min). Therefore, the change amount Xp is calculated by the controller 9 as −0.75 (0.9−1.65).

  On the other hand, when no oxidizing gas flows through the second oxidizing gas flow path 7, the flow rate B of the oxidizing gas flowing through the first oxidizing gas flow path 6 is 1.10 (NL / min). Therefore, the change amount Xo is −0.55 (1.10-1.65).

  Therefore, for example, when the threshold value is set to −0.65, it is determined that the valve 8 is out of order when the change amount calculated by (Equation 1) by the controller 9 is larger than the threshold value −0.65. Is done.

  Even when it is controlled to decrease the predetermined amount in this way, it is calculated from the value detected by the flow rate measuring device 5 as in the case of controlling to increase the operation amount of the oxidizing gas supply device 4. If the change amount is larger than a predetermined threshold value, it can be determined that the air bleed is not normally performed.

  The above results are summarized in Table 1 below.

  As can be seen from the respective explanation examples in (Table 1), when the operation amount of the oxidizing gas supply device 4 is constant, increases or decreases, it is calculated by (Equation 1). By using the relative change amount, it is possible to determine whether or not the air bleed is normally performed using the same determination formula (Formula 2). In the present invention, “when the change amount of the detection value of the flow measuring device is larger than the predetermined threshold value” means that “the change amount of the detection value of the flow measurement device is equal to the predetermined threshold value” when the valve 8 is controlled to open. It is possible to use any method regardless of the above-described determination method as long as it indicates a situation “greater than” and the situation can be detected.

  For example, in the present embodiment, (Equation 1) is used, but conversely to (Equation 1), the flow rate B after the opening command for the valve 8 may be subtracted from the flow rate A before the opening command for the valve 8. . However, in this case, the direction of the inequality sign in (Equation 2) is reversed, and when the amount of change is smaller than a predetermined threshold value, it is determined that the air bleed is not performed normally.

  In the above embodiment, the amount of change is defined as in (Equation 1) and has a positive / negative value, but the determination is performed using the absolute change amount that is the absolute value of (Equation 1). Also good. In this case, when described using the numerical values described in the present embodiment, the operating amount of the oxidizing gas supply device 4 is kept constant so that the supply amount of the oxidizing gas becomes 1.65 (NL / min). When the opening command is issued to the valve 8, the absolute change amount is 0.3 (NL / min) when the valve 8 is normally opened and the second oxidizing gas passage 7 is not clogged. On the other hand, when the valve 8 fails and does not open and no oxidizing gas flows through the second oxidizing gas flow path 7, the absolute change amount is zero. Therefore, when the threshold value is 0.15 (NL / min) and the absolute change amount is smaller than the threshold value, it can be determined that the air bleed is not normally performed.

  On the other hand, when the operating amount of the oxidizing gas supply device 4 is increased so as to increase the supply amount of the oxidizing gas from 1.65 (NL / min) to 2.2 (NL / min), the valve 8 opens normally. If the second oxidizing gas flow path 7 is not clogged, the absolute change amount is 0.15 (NL / min). On the other hand, when no oxidant gas flows through the second oxidant gas channel 7, the absolute change amount is 0.55 (NL / min). Therefore, when the threshold value Z is set to 0.35 (NL / min), when the absolute change amount is larger than 0.35, it can be determined that the air bleed is not normally performed.

  When the absolute change amount is used in this manner, unlike the case where the relative change amount is used, the control is performed according to the control (Equation 2 It is necessary to appropriately change the determination formula shown in FIG.

  Moreover, you may detect abnormality of an air bleed operation | movement based on the detected value itself of the flow measuring device 5, without using the above change amounts. As shown in (Equation 3) derived from (Equation 1) and (Equation 2), this is obtained by adding a value obtained by adding the threshold value Z to the flow rate A of the oxidizing gas when the valve 8 is closed. When the flow rate B of the oxidizing gas after the opening command to the valve 8 is larger than the threshold value Z ′, it is determined that the air bleed cannot be performed normally.

Flow rate B after opening command for valve 8> threshold value Z + flow rate A before opening command for valve 8 = threshold value Z ′ (Equation 3)

For example, when described using the numerical values described in the above-described embodiment, the operation amount of the oxidizing gas supply unit 4 is kept constant so that the oxidizing gas supply amount becomes 1.65 (NL / min). Since the threshold value Z that is set when an opening command is issued to the valve 8 in the state is −0.15, the threshold value Z ′ is 1.5 (NL / min). Therefore, when the flow rate B after the opening command to the valve 8 is larger than the threshold value Z ′, it can be determined that the air bleed operation is not normally performed.

  On the other hand, the threshold value Z set when the operating amount of the oxidizing gas supply unit is increased so as to increase the supply amount of the oxidizing gas from 1.65 (NL / min) to 2.2 (NL / min) is 0. Since it is 35, the threshold value Z ′ is 2.0.

  Therefore, when the flow rate B after the opening command to the valve 8 is larger than the threshold value Z ′, it can be determined that the air bleed operation is not normally performed.

  As described above, it is also possible to detect an abnormality in the air bleed operation by comparing the detection value itself of the flow rate measuring device 5 with the threshold value Z ′ as shown in (Expression 3) without using the change amount.

(Embodiment 2)
The fuel cell system according to Embodiment 2 of the present invention will be described below. The basic configuration of the fuel cell system of the present embodiment is the same as that of the first embodiment, but the determination method for determining that the air bleed is not normally performed is different. Therefore, this difference will be mainly described.

  In the fuel cell system of the present embodiment, for example, while adjusting the operation amount of the oxidizing gas supply device 4 so that the value measured by the flow rate measuring device 5 becomes a constant value, the valve 8 is opened and the air bleed is performed. When starting the operation, it is determined whether or not the air bleed is normally performed.

  In the above case, in the state where the valve 8 is closed, when the oxidizing gas supply device 4 is controlled so that the measurement value at the flow rate measuring device 5 becomes a constant value, the operation amount becomes a substantially constant value. From this state, when the valve 8 is opened while the measured value at the flow rate measuring device 5 is controlled to be a constant value, the first oxidizing gas channel 6 and the second oxidizing gas channel Therefore, the value measured by the flow rate measuring device 5 cannot be kept constant unless the operating amount of the oxidizing gas supply device 4 is increased.

  However, when the valve 8 does not operate normally and the controller 9 remains closed even when the opening command is issued, or when the second oxidizing gas flow path 7 is clogged with condensed water. It is assumed that the flow rate measured by the flow rate measuring device 5 is constant without changing the operation amount of the oxidizing gas supply device 4 or that the flow rate of the oxidizing gas flowing through the first oxidizing gas path 6 is reduced. Will be smaller than From this, when the valve 8 is changed from the closed state to the open state in order to start the air bleed, the air bleed is normally performed if the operation amount of the oxidizing gas supply device 4 does not change to a predetermined value or more. It can be determined that it is not.

  In the present embodiment, the change in the operation amount of the oxidizing gas supply device 4 is defined as (Equation 4) below.

Change Y = Operation amount D after opening command for valve 8−Operation amount C before opening command for valve 8 (Equation 4)

That is, after opening the valve 13, the controller 9 issues an operation command C of the oxidizing gas supply device 4 in a state where the flow rate measured by the flow rate measuring device 5 is stable, and an opening command to the valve 8. The change amount Y is calculated from the operation amount D. The calculated change amount Y is not an absolute value but a relative value having a positive or negative value.

  Next, the controller 9 compares the amount of change Y with a preset threshold value W. If the amount of change Y is smaller than the threshold value W, that is, if the following (Equation 5) is satisfied, the air bleed is performed. Is determined to have not been successfully implemented.

Change amount Y <threshold value W (Expression 5)

Further, the oxidizing gas when no oxidizing gas flows through the second oxidizing gas flow path 7 as in the case where the valve 8 does not operate at all or the second oxidizing gas flow path 7 is completely clogged. The change amount of the operation amount of the supply device 4 is set to Yo, the valve 13 is completely opened, and the first oxidizing gas channel 6 and the second oxidizing gas channel 7 are not clogged with condensed water. Assuming that the amount of change in the operation amount of the oxidizing gas supply device 4 in a state where the oxidizing gas flows at the above-described distribution ratio is Yp, the threshold value W can be set to the center value of Yo and Yp, for example. Note that the threshold value is not limited to the value because the value varies depending on the apparatus configuration, the way of branching of the oxidizing gas, and the like.

  The determination will be described using specific numerical values as examples.

  Here, when control is performed so that the value detected by the flow rate measuring device 5 is maintained at 1.35 (NL / min), before the valve 8 is opened, the oxidizing gas supply device 4 is, for example, a blower In this case, the operation amount C is the rotation speed R1 (rpm).

  When the valve 8 is instructed to be opened, the valve 8 is normally opened, and the second oxidizing gas flow path 7 is not clogged, as described in the first embodiment, the first Since the distribution ratio between the oxidizing gas channel 6 and the second oxidizing gas channel 7 is 4.5: 1, an attempt to maintain the value detected by the flow rate measuring device 5 at 1.35 (NL / min). The controller 9 needs to control the oxidizing gas supply device 4 so as to have a rotational speed R2 (rpm) corresponding to a flow rate of 1.65 (NL / min). Therefore, the change amount Yp of the operation amount (rotation speed) of the oxidizing gas supply device 4 is R2-R1.

  On the other hand, when the valve 8 fails and does not operate, or when the second oxidizing gas channel 7 is completely clogged with condensed water, no oxidizing gas is supplied to the second oxidizing gas channel 7. Since the supply amount by the oxidizing gas supply device 4 does not change, the change amount Yo of the operation amount (the number of revolutions) becomes zero.

  Therefore, when the threshold value W is set to (R2-R1) / 2, which is an intermediate value between the change amounts Yp and Yo, the controller 9 uses the change amount Y of the operation amount (rotation speed) as the threshold value (R2-R1). If it is smaller than / 2, it is determined that the air bleed cannot be performed normally.

  By determining as described above, even when the valve opening command is sent from the controller 9 and the valve 8 is not opened, or when the second oxidizing gas flow path 7 is clogged with water or the like, Can be detected.

  Therefore, in the fuel cell system according to the present embodiment, it is possible to confirm whether the air bleed is operating normally based on the operation amount of the oxidizing gas supply device 4, and to prevent the fuel cell system from deteriorating.

  In the present embodiment, the method for checking the operation of the valve 8 while controlling the detection value detected by the flow rate measuring device 5 to be a constant value has been described. Alternatively, if the amount of change in the operation amount of the oxidizing gas supply device 4 accompanying opening and closing of the valve 8 does not reach a predetermined value, it may be determined that the valve 8 is abnormal.

  For example, the oxidizing gas supply device 4 may be controlled so that the detection value of the flow rate measuring device 5 becomes a target detection value increased by a predetermined value. Hereinafter, a case where control is performed so that the target detection value is increased will be described by taking specific numerical values as examples.

(Example of detection value increase control)
In the state where the valve 8 is closed, the operation amount of the oxidant gas supply device 4 is controlled so that the detected value becomes 1.65 (NL / min), and the target value of the detected value is 1 together with the opening command of the valve 8. A case where the control is performed so as to be set to .8 (NL / min) will be described as an example.

  In order for the detected value to be 1.65 (NL / min) when the valve 8 is closed, when the oxidizing gas supply 4 is a blower, the rotation speed is controlled to be R2 (rpm). Yes.

  In such a case, when the valve 8 is completely opened and the second oxidizing gas channel 7 is not clogged, the detection value at the flow rate measuring device 5 is 1.8 (NL / min). In order to do this, the oxidizing gas corresponding to a flow rate of 0.4 (NL / min) is distributed to the second oxidizing gas flow path 7, so that the operation amount D of the oxidizing gas supply device 4 is equal to the oxidizing gas supply device 4. It is necessary to set the rotational speed to R3 (rpm) so that the supply amount of oxidizing gas from the reactor becomes 2.2 (NL / min). Therefore, the change amount Yp of the manipulated variable is R3-R2.

  On the other hand, when the valve 8 does not operate or when the second oxidizing gas flow path 7 is completely clogged, no oxidizing gas flows into the second oxidizing gas flow path 7 and the oxidizing gas supply 4 Since the operating amount D is the rotational speed R4 at which the oxidizing gas supply amount from the oxidizing gas supply device is 1.8 (NL / min), the change amount Yo of the supply amount is R4-R2.

  Therefore, for example, if the threshold value is set as an intermediate value between the change amounts Yp and Yo, the value becomes {(R3−R2) + (R4−R2)} / 2 = (R3 + R4) / 2−R2. When the change amount Y is smaller than the threshold value W (R3 + R4) / 2−R2, it can be determined that the air bleed is not normally performed.

  Further, for example, the operation amount of the oxidizing gas supply device 4 may be controlled so that the detection value of the flow rate measuring device 5 becomes a target detection value reduced by a predetermined value. Hereinafter, a specific numerical value will be described as an example in the case where control is performed so that the target detection value is decreased by a predetermined value.

(Example of detection value reduction control)
The case where the target value of the detected value of the flow rate measurement value 5 is changed from 1.65 (NL / min) to 0.9 (NL / min) and an opening command is issued to the valve 8 will be described as an example. To do.

  In order for the detected value to be 1.65 (NL / min) when the valve 8 is closed, the operation amount C of the oxidizing gas supplier 4 is controlled to be R2. In this example, the target value of the detected value of the flow rate measurement value 5 is set to 0.9 (NL / min) together with the opening command of the valve 8.

  In such a case, the value detected by the flow rate measuring device 5 is 0.9 (NL / min) in a state where the valve 8 is normally opened and the second oxidizing gas flow path 7 is not clogged. In order to do so, the oxidizing gas corresponding to a flow rate of 0.2 (NL / min) is distributed to the second oxidizing gas flow path 7, so that the operation amount D of the oxidizing gas supply device 4 is reduced from the oxidizing gas supply device 4. It is necessary to set it to R5 (rpm) so that the oxidizing gas flow rate becomes 1.1 (NL / min). Therefore, the change amount Yp of the manipulated variable is R5-R2.

  On the other hand, when the oxidizing gas does not flow at all in the second oxidizing gas flow path 7, the operation amount D of the oxidizing gas supply unit 4 is such that the oxidizing gas flow rate from the oxidizing gas supply unit 4 is 0.9 (NL / It is necessary to set R6 (rpm) to be equal to min). Therefore, the supply amount change amount Yo is R6-R2.

  Therefore, as in the example of the detection value increase control, for example, if the threshold value W is set to (R5 + R6) / 2−R2 which is an intermediate value between the change amounts Yp and Yo, the change amount Y of the operation amount is the threshold value W. If it is smaller than that, it can be determined that the air bleed is not normally performed.

  The above results are summarized in (Table 2).

  Further, the following (Table 3) summarizes the correspondence relationship between the rotational speeds R1 to R6 as the operation amount of the oxidizing gas supply device 4 and the oxidizing gas supply amount from the oxidizing gas supply device 4.

  In order to increase the supply amount of the oxidizing gas from the oxidizing gas supply device 4, it is necessary to increase the rotation speed, so that the rotation speed increases from left to right in the above (Table 3).

  Therefore, each value in the row of the detection value constant control in (Table 2) is a positive value, and when the amount of change in the rotational speed is smaller than the threshold value (R2-R1) / 2, the air bleed is normally performed. It is determined that it is not completed.

  In addition, since each value in the row of detection value increase control in (Table 2) is also a positive value and (R4-R2) is smaller than (R3-R2), the amount of change in the rotational speed is the threshold value (R3 + R4). If it is smaller than / 2-R2, it is determined that the air bleed cannot be performed normally.

  Further, since each value in the row of detection value reduction control in (Table 2) is a negative value and (R6-R2) is smaller than (R5-R2), the amount of change in the rotational speed is the threshold value (R5 + R6). ) / 2−R2 is smaller, it is determined that the air bleed is not normally performed.

  Thus, even if it is controlled to decrease or increase the target set value of the detected value of the flow rate detector 5, even if it is controlled to keep the detected value constant, the amount of change is ( It is possible to determine that the air bleed is not normally performed by the determination formula of (Formula 5) by providing a positive / negative distinction as a relative value instead of the absolute value of Formula 4). I can do it.

  In the above embodiment, the amount of change is defined as in (Expression 4) and has a positive and negative value as the relative change amount. However, the absolute change amount that is the absolute value of (Expression 4) is The determination may be made by using. However, if the absolute value is used, if the detection target value shown in (Table 2) is decreased, | R6-R2 | becomes larger than | R5-R2 | It is necessary to change to> W.

  In the fuel cell system according to the present embodiment, the “operation amount of the oxidizing gas supply device” of the present invention is detected by, for example, an operation amount detector (not shown) provided in the oxidizing gas supply device 4 itself. Based on this detected value, the controller 9 may determine whether the air bleed operation is normal based on (Equation 5). As another example, the “operating amount of the oxidizing gas supply device” of the present invention is a control command value of the operating amount of the oxidizing gas supply device 4 output from the controller 9 to the oxidizing gas supply device 4. The device 9 may determine whether the air bleed operation is normal based on (Equation 5). That is, “when the increase amount of the operating amount of the oxidizing gas supply device is smaller than the predetermined threshold” of the present invention means that “the increase amount of the operating amount of the oxidizing gas supply device is the predetermined amount when the valve 8 is controlled to open. The method of referring to a situation that is “smaller than a threshold” and detecting the situation may be the above method, and is not limited to the above method as long as this situation can be detected. I do not care.

  The fuel cell system according to the present invention has an effect that it is possible to detect that the oxidizing gas for air bleed is not normally supplied and to prevent the deterioration of the fuel cell from progressing. This is useful for a fuel cell system that continues to operate over a period of time.

1 is a block diagram schematically showing the configuration of a fuel cell system according to Embodiment 1 of the present invention. The figure for demonstrating the control flow of the fuel cell system in Embodiment 1 concerning this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Reformer 2 CO removal device 3 Fuel cell 4 Oxidizing gas supply 5 Flow rate measuring device 6 1st oxidizing gas flow path 7 2nd oxidizing gas flow path 8 Valve 9 Controller 10 Hydrogen containing gas flow path 11 Hydrogen containing Gas flow path 12 Abnormality alarm 13 Valve 14 Branch

Claims (11)

A reformer that generates hydrogen-containing gas using raw materials;
A CO remover for reducing carbon monoxide in the hydrogen-containing gas by an oxidation reaction;
An oxidizing gas supply for supplying oxidizing gas;
A fuel cell that generates power using the hydrogen-containing gas delivered from the CO remover;
A first oxidizing gas flow path for mixing the oxidizing gas supplied from the oxidizing gas supplier into the hydrogen-containing gas supplied to the CO remover;
A second oxidizing gas channel for branching from the first oxidizing gas channel and mixing the oxidizing gas into the hydrogen-containing gas delivered from the CO remover;
A flow rate measuring device provided in the first oxidizing gas flow path downstream from the branching portion;
A valve provided in the second oxidizing gas flow path downstream from the branch part;
With a controller,
The fuel cell system characterized in that the controller stops operation based on a detection value of the flow rate measuring device when the valve is opened during the operation of the oxidizing gas supply device.   The controller is configured to stop the operation when the amount of change in the detected value of the flow rate measuring device is larger than a predetermined threshold when the valve is opened during the operation of the oxidizing gas supply device. The fuel cell system according to claim 1, wherein:   The controller controls the operating amount of the oxidant gas supply device to be constant and operates when the amount of change in the detected value of the flow meter when the valve is controlled to open is larger than a predetermined threshold value. The fuel cell system according to claim 2, wherein the fuel cell system is stopped.   The controller controls to increase the operation amount of the oxidizing gas supply device, and when the change amount of the detection value of the flow rate measuring device when controlling to open the valve is larger than a predetermined threshold, The fuel cell system according to claim 2, wherein the operation is stopped.   If the amount of change in the value detected by the flow meter when the controller controls to open the valve during the operation of the oxidizing gas supply device is larger than a predetermined threshold value, an error is indicated. The fuel cell system according to claim 2, further comprising an abnormality alarm device for reporting.   During the operation of the oxidizing gas supply device, the controller continues more than once that the amount of change in the value detected by the flow meter when the valve is controlled to open is greater than a predetermined threshold value. 3. The fuel cell system according to claim 2, wherein the operation is stopped when the operation is performed. A reformer that generates hydrogen-containing gas using raw materials;
A CO remover for reducing carbon monoxide in the hydrogen-containing gas by an oxidation reaction;
An oxidizing gas supply for supplying oxidizing gas;
A fuel cell that generates power using the hydrogen-containing gas delivered from the CO remover;
A first oxidizing gas flow path for mixing the oxidizing gas supplied from the oxidizing gas supplier into the hydrogen-containing gas supplied to the CO remover;
A second oxidizing gas channel for branching from the first oxidizing gas channel and mixing the oxidizing gas into the hydrogen-containing gas delivered from the CO remover;
A flow rate measuring device provided in the first oxidizing gas flow path downstream from the branching portion;
A valve provided in the second oxidizing gas flow path downstream from the branch part;
With a controller,
The controller operates the oxidizing gas supply when controlling the opening of the valve while controlling the operation amount of the oxidizing gas supply so that the value detected by the flow measuring device becomes a predetermined value. A fuel cell system characterized in that the operation is stopped when the amount of increase is smaller than a predetermined threshold.   The controller controls the operating amount of the oxidizing gas supplier so that the value detected by the flow meter is maintained at a predetermined value, and controls the oxidizing gas supplier to open the valve. 8. The fuel cell system according to claim 7, wherein the operation is stopped when the increase amount of the manipulated variable is smaller than a predetermined threshold value.   The controller controls the operating amount of the oxidizing gas supplier so that the value detected by the flow meter increases by a predetermined amount, and operates the oxidizing gas supplier when controlling the valve to open. 8. The fuel cell system according to claim 7, wherein when the amount of increase is smaller than a predetermined threshold, the operation is stopped.   The oxidizing gas supply device when the controller controls to open the valve while controlling the operation amount of the oxidizing gas supply device so that the value detected by the flow rate measuring device is maintained at a predetermined value. 8. The fuel cell system according to claim 7, further comprising an abnormality notifier for notifying that an abnormality has occurred when the amount of increase in the control command value of the operation amount is smaller than a predetermined threshold value. The controller is configured to control the oxidant gas supply unit to open the valve while controlling the operation amount of the oxidant gas supply unit so that the value detected by the flow rate measuring device is maintained at a predetermined value. 8. The fuel cell system according to claim 7, wherein the operation is stopped when the increase amount of the operation amount is smaller than a predetermined threshold value for a plurality of times.

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