JP5851946B2 - Fuel cell system - Google Patents

Description

  The present invention relates to a fuel cell system and an abnormality detection method thereof.

  As a conventional method for detecting an abnormality in a fuel cell system, for example, the one shown in Patent Document 1 is known. In the system shown in Patent Document 1, a combustor, a fuel processor, and a fuel cell stack are housed in a casing, and a gas detector is provided in the casing. When the detection signal is received from the gas detector, the valve is closed and the supply of the combustible gas is stopped. Further, in the system of Patent Document 2, when the temperature of the catalyst layer becomes equal to or lower than the decomposition temperature of the raw fuel gas when the fuel cell system is stopped, the raw fuel gas is sealed and sealed in the reformer. In the state, the temperature and pressure of the sealed space are detected with time, and the pressure drop speed based on the detection result is compared with the pressure drop speed calculated by the calculation, thereby determining the airtight abnormality.

Republished patent WO2008 / 023729 JP 2010-15808 A

  Here, the system according to Patent Document 1 has a problem that the gas detector cannot detect until a certain amount of gas is present in the housing. In addition, although gas can be detected if there is gas in the housing, there is a problem that abnormalities related to airtightness inside the apparatus such as a valve failure cannot be detected. Further, in the system according to Patent Document 2, an abnormality related to airtightness (damage such as a crack) may occur while the system is stopped. In such a case, the abnormality may be detected until the next operation is stopped. There was a problem that the operation was performed in an abnormal state. Furthermore, in the detection method based on the pressure drop speed at the time of stopping, there may be a case where an abnormality relating to airtightness cannot be detected accurately. Therefore, it has been conventionally required to detect an abnormality related to airtightness in a fuel cell system in a shorter time and accurately.

  Therefore, an object of the present invention is to provide a fuel cell system and an abnormality detection method capable of accurately detecting an abnormality related to airtightness in a shorter time and more accurately.

A fuel cell system according to the present invention includes a hydrogen production unit that produces a reformed gas containing hydrogen using raw fuel, a fuel cell stack that generates electric power using the reformed gas produced by the hydrogen production unit, An abnormality detection unit comprising an opening / closing part that opens and closes the outlet side of the reformed gas in the hydrogen production part, a pressure detection part that detects a pressure upstream of the opening / closing part, and an abnormality detection part that detects an abnormality in the system. When the system is started, the opening / closing unit is closed, and the value based on the pressure detected by the pressure detection unit when the raw fuel is supplied to the hydrogen production unit is less than the first threshold value, The abnormality detection unit detects an abnormality related to airtightness by comparing the value based on the pressure with a second threshold smaller than the first threshold .

When the reformed gas outlet side of the hydrogen production unit is closed by the open / close unit and the raw fuel is supplied to the hydrogen production unit, if there is no abnormality related to airtightness, the pressure increases upstream from the open / close unit. . On the other hand, when there is an abnormality related to airtightness, the pressure increase is smaller than when there is no abnormality. Therefore, by setting the first threshold value in advance as a value when there is no abnormality with respect to the value based on the pressure under the condition, the abnormality detection unit can detect the pressure under the condition when the system is started. When the value based on the pressure detected by the unit is smaller than the first threshold value, it is possible to detect an abnormality related to airtightness. Since the abnormality detection unit can detect an abnormality at the time of system startup, it can prevent the fuel cell system from being operated in a state where there is an abnormality related to airtightness. In addition, if the raw fuel is supplied by closing the outlet side of the hydrogen production department when the system is started up, the pressure rises in a short time, so that an abnormality can be detected quickly, and the pressure is clearly determined when there is an abnormality and when there is no abnormality. Therefore, an abnormality can be accurately detected. As described above, an abnormality relating to airtightness can be detected in a shorter time and more accurately. In addition, when there is an abnormality related to airtightness, the pressure increase when the reforming is performed with the opening / closing part closed is small, but the degree of the pressure increase is different depending on the abnormal part. Therefore, by comparing the value based on the pressure and the second threshold value, it is possible to determine the location of the abnormality, thereby making it possible to efficiently perform repair after detecting the abnormality.

The abnormality detection method according to the present invention includes a hydrogen production unit that generates a reformed gas containing hydrogen using raw fuel, and a fuel cell stack that generates power using the reformed gas generated by the hydrogen production unit. An abnormality detection method for detecting an abnormality in a fuel cell system comprising: a closing step of closing the reformed gas outlet side of the hydrogen production section with an opening / closing section; and a pressure for detecting a pressure upstream of the opening / closing section A pressure detecting step, and a pressure detecting step for detecting an abnormality in the system. In the pressure detecting step, the pressure when the closing process is executed and the raw fuel is supplied to the hydrogen production section is started at the time of starting the system. In the detection and abnormality detection step, when the value based on the pressure is smaller than the first threshold, an abnormality related to airtightness is detected , and the value based on the pressure and the second threshold smaller than the first threshold are detected. By comparing with Determining an abnormality of the position regarding airtightness.

In the abnormality detection step, an abnormality can be detected when the system is started, and therefore it is possible to prevent the fuel cell system from being operated in a state where there is an abnormality related to airtightness. Also, when the reforming is performed by closing the outlet side of the hydrogen production section when the system is started, the pressure rises in a short time, so that an abnormality can be detected quickly, and there is a clear difference in pressure between when there is an abnormality and when there is no abnormality. Therefore, the abnormality can be detected accurately. As described above, an abnormality relating to airtightness can be detected in a shorter time and more accurately. In addition, when there is an abnormality related to airtightness, the pressure increase when the reforming is performed with the opening / closing part closed is small, but the degree of the pressure increase is different depending on the abnormal part. Therefore, by comparing the value based on the pressure and the second threshold value, it is possible to determine the location of the abnormality, thereby making it possible to efficiently perform repair after detecting the abnormality.

  The fuel cell system further includes a temperature detection unit that detects a temperature of the hydrogen production unit, and the abnormality detection unit is configured to detect the raw fuel based on the temperature detected by the temperature detection unit after the start of temperature increase in the hydrogen production unit. Detect an abnormality related to supply. This makes it possible to detect an abnormality related to the raw fuel before detecting an abnormality related to airtightness.

  The fuel cell system further includes a temperature detection unit that detects the temperature of the hydrogen production unit, and the abnormality detection unit performs reforming based on the temperature detected by the temperature detection unit after the start of reforming in the hydrogen production unit. Detect abnormalities in water supply. This makes it possible to detect an abnormality related to the supply of reforming water before detecting an abnormality related to airtightness.

  According to the present invention, an abnormality relating to airtightness can be detected more accurately in a shorter time.

It is a schematic block diagram which shows a part of fuel cell system which concerns on one Embodiment of this invention. It is a schematic block diagram which shows the structure of the control part of FIG. It is a flowchart which shows the processing content of the fuel cell system which concerns on one Embodiment of this invention. It is a flowchart which shows the processing content which concerns on a modification.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In the following description, the same or equivalent elements will be denoted by the same reference numerals, and redundant description will be omitted.

  FIG. 1 is a schematic block diagram showing a part of a fuel cell system according to an embodiment of the present invention. As shown in FIG. 1, a hydrogen production apparatus (FPS: Fuel Processing System) 1 is used as a hydrogen supply source in, for example, a household fuel cell system 100. The hydrogen production apparatus (hydrogen production unit) 1 here supplies a reformed gas containing hydrogen to the fuel cell stack 20. The fuel cell stack 20 generates power using the reformed gas and the oxidant. The fuel cell stack 20 can employ, for example, a polymer electrolyte fuel cell (PEFC). As the oxidizing agent, for example, air, pure oxygen gas (which may contain impurities that are difficult to remove by a normal removal method), or oxygen-enriched air is used.

  As the raw fuel for the hydrogen production apparatus 1 according to the present embodiment, for example, a hydrocarbon fuel is used. As the hydrocarbon fuel, a compound containing carbon and hydrogen in the molecule (may contain other elements such as oxygen) or a mixture thereof is used. Examples of hydrocarbon fuels include hydrocarbons, alcohols, ethers, and biofuels. These hydrocarbon fuels are derived from conventional fossil fuels such as petroleum and coal, and synthetic systems such as synthesis gas. Those derived from fuel and those derived from biomass can be used as appropriate. Specific examples of hydrocarbons include methane, ethane, propane, butane, natural gas, LPG (liquefied petroleum gas), city gas, town gas, gasoline, naphtha, kerosene, and light oil. Examples of alcohols include methanol and ethanol. Examples of ethers include dimethyl ether. Examples of biofuels include biogas, bioethanol, biodiesel, and biojet.

  The fuel cell system 100 includes a hydrogen production device 1, a desulfurization unit 2, heating devices 10 and 11, a fuel cell stack 20, and a control unit 30. The hydrogen production apparatus 1 includes a reforming unit 6, a shift reaction unit 7, and a selective oxidation reaction unit 8. A pump 21, a three-way valve 22, and a pressure gauge (pressure detector) 23 are provided in the flow path on the inlet side of the hydrogen production apparatus 1, that is, the flow path between the desulfurization section 2 and the hydrogen production apparatus 1. A pump 24 for supplying reforming water is connected to the reforming unit 6 of the hydrogen production apparatus 1. An opening / closing valve 26 is provided in the flow path on the outlet side of the hydrogen production apparatus 1, that is, the flow path between the selective oxidation reaction unit 8 of the hydrogen production apparatus 1 and the fuel cell stack 20. The hydrogen production apparatus 1 is provided with a thermometer (temperature detector) 27 for measuring temperature.

  The desulfurization unit 2 desulfurizes raw fuel introduced from the outside with a desulfurization catalyst to remove sulfur. The raw fuel from which the sulfur content has been removed is supplied to the reforming unit 6 of the hydrogen production apparatus 1 by the pump 21.

  A reforming section (SR: Steam Reforming) 6 generates a reformed gas by steam reforming a mixed gas of raw fuel gas supplied from the desulfurization section 2 and steam with reformed water using a reforming catalyst, This reformed gas is supplied to the shift reaction unit 7. In the reforming unit 6, since the steam reforming reaction is an endothermic reaction, the heating device 10 is used as a heat source for heating the reforming catalyst of the reforming unit 6.

  The shift reaction unit 7 is for lowering the carbon monoxide concentration (CO concentration) of the reformed gas supplied from the reforming unit 6, and shifts the carbon monoxide in the reformed gas to generate hydrogen and Convert to carbon dioxide.

  A selective oxidation reaction unit (PROX) 8 further reduces the CO concentration in the reformed gas subjected to the shift reaction in the shift reaction unit 7. This is because if a high concentration of carbon monoxide is supplied to the fuel cell stack 20, the catalyst of the fuel cell stack 20 is poisoned and the performance is greatly reduced. Specifically, the selective oxidation reaction unit 8 causes carbon monoxide and an oxidizing agent in the reformed gas to react with each other with a selective oxidation catalyst to selectively oxidize the carbon dioxide and convert it into carbon dioxide.

  The heating device 10 is a device for heating the reforming unit 6, and for example, a burner is applied. In the heating device 10, the raw fuel is supplied as burner fuel and burned (for example, the raw fuel flows to the heating device 10 by opening and closing the three-way valve 22). The heating device 11 is a device for heating the shift reaction unit 7 and the selective oxidation reaction unit 8, and for example, a heater or the like is applied.

  In such a hydrogen production apparatus 1, first, at least one of burner fuel and off-gas from the fuel cell stack 20 (residual gas not used for reaction in the fuel cell stack 20) and air are supplied to the heating device 10 and burned. Thus, the reforming catalyst of the reforming unit 6 is heated by such combustion. At the same time, the raw fuel desulfurized in the desulfurization unit 2 and the water vapor by the reformed water supplied by the pump 24 are mixed to generate a mixed gas. This mixed gas is supplied to the reforming unit 6 and subjected to steam reforming by the reforming catalyst, thereby generating reformed gas. The generated reformed gas has its carbon monoxide concentration reduced to, for example, about several percent by the shift reaction unit 7, and after its carbon monoxide concentration has been reduced to 10 ppm or less by the selective oxidation reaction unit 8, the hydrogen-rich gas. To the fuel cell stack 20 at the subsequent stage.

  The pressure gauge 23 has a function of detecting the pressure of the raw fuel gas supplied to the hydrogen production unit 1 on the upstream side of the hydrogen production apparatus 1. The pressure gauge 23 has a function of detecting a pressure change caused by closing the on-off valve 26. The pressure gauge 23 may be provided at any position upstream of the on-off valve 26 as long as it can detect the pressure of at least one of the raw fuel gas and the reformed gas. For example, it is provided in a flow path between the selective oxidation unit 8 of the hydrogen production apparatus 1 and the on-off valve 26, and the pressure of the reformed gas (the pressure of the raw fuel gas in a state where the reforming in the hydrogen production apparatus 1 is not performed). ) May be detected. However, the existing pressure gauge can be diverted by using the pressure of the pressure gauge 23 provided between the pump 21 and the hydrogen production apparatus 1 for the flow rate control or the like in the abnormality detection method of this embodiment. Can do. A plurality of pressure gauges 23 may be provided to measure both the pressure of the raw fuel gas and the pressure of the reformed gas.

  The thermometer 27 has a function of detecting the temperature of the hydrogen production apparatus 1. The thermometer 27 may detect any temperature as long as it can be determined that the hydrogen production apparatus 1 has reached a reformable temperature. For example, the thermometer 27 may detect the temperature at the representative point or the outlet of the reforming catalyst layer of the reforming unit 6, or detect the temperature of the catalyst layer of the shift reaction unit 7 or the selective oxidation reaction unit 8. Also good. Moreover, you may detect the temperature of several places.

  The control unit 30 has a function of controlling the entire fuel cell system 100. For example, a device that performs electronic control (for example, a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), And a device configured to include an input / output interface). The control unit 30 is electrically connected to the pump 21, the three-way valve 22, the pressure gauge 23, the pump 24, the thermometer 27, the on-off valve 26, and other sensors and electronic devices in the fuel cell system 100 (not shown). I / O is performed. As shown in FIG. 2, the control unit 30 includes an operation control unit 31, an opening / closing control unit 32, a temperature acquisition unit 33, a pressure acquisition unit 34, and an abnormality detection unit 35.

  The operation control unit 31 has a function of performing operation control of the fuel cell system 100, and performs control for producing hydrogen in the hydrogen production apparatus 1 and control for generating power in the fuel cell stack 20. For example, the operation control unit 31 controls the pumps 21 and 24 to supply raw fuel, reforming water, and oxidant to each part at a predetermined timing.

  The open / close control unit 32 has a function of executing open / close control of the open / close valve 26. The open / close control unit 32 controls the open / close valve 26 to be closed when detecting an abnormality related to the airtightness of the fuel cell system 100 at the time of system startup. The temperature acquisition unit 33 has a function of acquiring the temperature detected by the thermometer 27. The pressure acquisition unit 34 has a function of acquiring the pressure detected by the pressure gauge 23.

  The abnormality detection unit 35 has a function of detecting an abnormality in the fuel cell system 100. The abnormality detection unit 35 is configured such that the value based on the pressure detected by the pressure gauge 23 when the on-off valve 26 is closed and the raw fuel is supplied to the hydrogen production device 1 is equal to or less than the first threshold value. In addition, it has a function of detecting an abnormality related to airtightness. Note that any value may be used as the “value based on pressure” used for abnormality detection. For example, a value of a pressure change amount within a predetermined time (a value corresponding to ΔP when the pressure is represented by P). May be used. In addition, a fixed pressure value may be used (P is used instead of ΔP). When the on-off valve 26 is closed and the raw fuel is supplied to the hydrogen production apparatus 1, since the raw fuel gas and the reformed gas are stored in the flow path of the hydrogen production apparatus 1, the pressure increases. The pressure increase when there is an abnormality in airtightness is slower than the pressure increase when there is no abnormality. Therefore, an abnormality relating to airtightness can be detected by comparing a value based on pressure with a predetermined threshold value.

  The abnormality detection unit 35 has a function of determining a location of an abnormality related to airtightness by comparing a value based on pressure with a second threshold value that is smaller than the first threshold value. Determining the location of abnormality is to determine whether there is an abnormality in the airtightness of the hydrogen production apparatus 1 or whether there is an abnormality in the on-off valve 26 on the outlet side. When there is an abnormality in the on-off valve 26 on the outlet side, the influence on the pressure is greater than when there is an abnormality in the hydrogen production apparatus 1, and the pressure increase is delayed. Therefore, by comparing the value based on the detected pressure with a predetermined threshold value, it is possible to determine the location of abnormality related to airtightness. In addition, the state where there is an abnormality in the airtightness of the hydrogen production apparatus 1 refers to the hydrogen production apparatus 1 to the outside (however, in the case where the entire hydrogen production apparatus 1 is housed in the enclosure). A trace amount of gas comes out. Examples of the abnormality in the air tightness of the hydrogen production apparatus 1 include a crack in the outermost wall of the hydrogen production apparatus 1 and a lack of sealability at a connection portion (such as a pipe). As an abnormality of the airtightness of the on-off valve 26, for example, it cannot be closed due to a failure.

  The abnormality detection unit 35 has a function of detecting an abnormality related to the supply of raw fuel based on the temperature detected by the thermometer 27. The abnormality detection unit 35 can detect an abnormality related to the supply of raw fuel based on the temperature detected after the start of the temperature increase of the hydrogen production apparatus 1. The abnormality detection unit 35 detects an abnormality based on the state of temperature rise when the temperature is raised to a temperature at which reforming can be started in the hydrogen production apparatus 1. When a burner is used as the heating device 10 for heating the reforming unit 6, when ignition does not occur or the temperature rise rate of the hydrogen production device 1 is low, a malfunction of the raw fuel system, that is, an abnormality related to the supply of the raw fuel is estimated. The Examples of abnormalities related to the supply of raw fuel include a failure of the pump 21 for supplying raw fuel, a failure of the three-way valve 22 serving as a supply valve, and a clogged pipe.

  The abnormality detection unit 35 has a function of detecting an abnormality related to the supply of reforming water based on the temperature detected by the thermometer 27. The abnormality detection unit 35 can detect an abnormality of the reforming water system based on the temperature after the start of reforming in the hydrogen production apparatus 1 in the hydrogen production apparatus 1. When the pump 24 is controlled so that the reforming water is supplied to the hydrogen production apparatus 1 and the pump 21 is controlled so that the raw fuel is supplied, that is, when reforming in the hydrogen production apparatus 1 is started, The temperature of the hydrogen production apparatus 1 is affected by the endothermic reaction in the reforming unit 6. However, when the endothermic reaction does not occur (reforming does not occur) and the temperature is abnormal, a failure of the reforming water system, that is, an abnormality related to the supply of the reforming water is estimated. Examples of the abnormality relating to the supply of reforming water include a failure of the reforming water supply pump 24, a failure of the reforming water supply valve, and a clogged pipe.

  Next, with reference to FIG. 3, the abnormality detection method of the fuel cell system 100 according to the present embodiment will be described. FIG. 3 is a flowchart showing the processing contents of the fuel cell system 100. The process shown in FIG. 3 is a process for detecting an abnormality in the fuel cell system 100 when the system is activated. The process of FIG. 3 is executed at a predetermined timing in the control unit 30 when the fuel cell system 100 is activated. Here, “system activation” includes both cold start and hot start. Moreover, the processing content of FIG. 3 is only an example, and you may change a processing content and the order of a process suitably.

As shown in FIG. 3, the operation control unit 31 starts system activation of the fuel cell system 100 (step S <b> 10). The operation control unit 31 controls the pump 21 and the three-way valve 22 to supply raw fuel to the heating device 10 as a burner and ignite it, and also controls the heating device 11 (turns on the heater) to produce hydrogen. The temperature rise of the apparatus 1 is started (step S20). It should be noted that in the stage of S20, a predetermined device or the like in the fuel cell system 100 may be activated within a range that does not affect processing for detecting an abnormality described later (for example, a fuel cell stack). Side equipment, waste heat equipment, etc.). Next, the operation control unit 31 supplies the reforming water to the reforming unit 6 by controlling the pump 24 (step S30). Temperature acquisition unit 33, by starting acquisition of the thermometer 27 of the detection result, to start the measurement of the temperature T _C of the hydrogen production apparatus 1 (step S40). Abnormality detector 35, the temperature _{T C} measured in S40 is equal to or modification start condition determination temperature _{T L} above (step S50). Incidentally, the reforming start condition determination temperature T _L is the temperature that indicates that a hydrogen production apparatus 1 is raised to be able to initiate a modification, any value for such measurement spots the temperature T _C Is set. For example, if the temperature T _C was the temperature of the representative points of the reforming catalyst layer of the reforming section 6, reforming temperature (e.g., 600 to 650 ° C.) at which it is possible to reforming in the reforming catalyst layer It can be set as the quality start condition determination temperature _TL . If the temperature T _C was the temperature of the different measurement points, different modification start condition determining temperature T _L is set. In addition, you may determine the reforming start condition determination temperature _TL about the temperature in several places.

In S50, when the temperature T _C is determined to be modified start condition determination temperature T _L is less than, the abnormality detecting unit 35 determines whether a predetermined time has elapsed from the start heating (step S60). As the predetermined time, when there is no abnormality in the fuel cell system 100, it is possible to set a time required from the start of the temperature rise to the reforming start condition determination temperature _TL . The predetermined time can be set to 5 to 120 minutes. If it is determined in S60 that the predetermined time has not elapsed, the process of S50 is performed again. On the other hand, when it is determined in S60 that the predetermined time has elapsed, the abnormality detection unit 35 detects an abnormality related to the supply of raw fuel, that is, an abnormality of the raw fuel system (step S70). Although the control is performed so that the raw fuel is supplied to the burner of the heating apparatus 10, the temperature of the hydrogen production apparatus 1 has not been raised to a temperature at which reforming can be performed within a predetermined time. It is estimated that the burner did not ignite and heating was not performed, and that sufficient heating power was not obtained and the rate of temperature increase was low. When an abnormality is detected in S70, the operation control unit 31 stops the system startup process (step S80). That is, the operation control unit 31 stops the operation of each device in the system. After the activation process is stopped in S80, the process illustrated in FIG. 3 ends. Thereafter, the raw material system in the fuel cell system 100 may be inspected.

On the other hand, in S50, the temperature T _C if it is determined that the reforming start condition determination temperature T _L above, i.e., became temperature conditions, such as reforming can begin in a hydrogen production apparatus 1 within a predetermined time When it is determined, the opening / closing control unit 32 closes the outlet of the hydrogen production apparatus 1 by closing the opening / closing valve 26 (step S90). Next, the operation control unit 31 starts reforming in the hydrogen production apparatus 1 (step S100). The operation control unit 31 controls the pump 21 to supply the raw fuel to the reforming unit 6 of the hydrogen production apparatus 1 to start reforming in the hydrogen production apparatus 1. As a result, the reformed gas is generated in the hydrogen production apparatus 1, while the on-off valve 26 is closed, whereby the pressure in the hydrogen production apparatus 1 increases. The pressure acquisition unit 34 is a pressure gauge 23 when the reformed gas outlet side of the hydrogen production apparatus 1 is closed by the on-off valve 26 and the raw fuel is supplied to perform reforming in the hydrogen production apparatus 1. The pressure change amount ΔP within a predetermined time is acquired (step S110). In addition, what is the “predetermined time” here as long as it is possible to make a difference in the amount of pressure change to the extent that it is possible to determine when there is an abnormality and when there is no abnormality? It may be set.

Abnormality detector 35, the pressure change amount ΔP acquired in S110 determines whether the first threshold value _{P 1} abnormality (step S120). The first threshold value P ₁ is a threshold value set in advance in order to detect the presence / absence of an abnormality related to the airtightness of the fuel cell system 100. The first threshold value P ₁ is, for example, by measuring the position of the pressure gauge 23 may be modified as desired. If the pressure change amount ΔP is determined to be the first threshold value P ₁ or more in S120, the abnormality detector 35, the airtightness of the abnormality is judged that there is no. Thereafter, the opening / closing control unit 32 opens the outlet of the hydrogen production apparatus 1 by opening the opening / closing valve 26 (step S130). As a result, the reformed gas generated by the hydrogen production apparatus 1 is supplied to the fuel cell stack 20. The operation control unit 31 continues the startup process (step S140), and executes each process that is necessary for generating power in the fuel cell system 100 and that has not been executed by S140. For example, the operation control unit 31 starts an operation of a device (for example, an oxidant pump) on the fuel cell stack 20 side. When S140 ends, the operation of the fuel cell system 100 is continued.

On the other hand, if the pressure change amount ΔP is determined that the first threshold value P ₁ is smaller than in S120, the abnormality detecting unit 35 determines that there is an abnormality regarding airtightness in the fuel cell system 100, the location of abnormality relating airtightness It determined in order to determine, whether the pressure change amount ΔP is the second threshold value P ₂ or more (step S150). The second threshold value P ₂ is whether there is abnormality in the air-tightness of the hydrogen production apparatus 1, in order to determine whether there is an abnormality in the opening and closing valve 26 on the outlet side, a preset threshold value. The second threshold value P ₂ is such as by measuring the position of the pressure gauge 23 may be modified as desired. If the pressure change amount ΔP is determined to be the second threshold value P ₂ than in S150, the abnormality detecting unit 35 detects the air-tightness of an abnormality in the hydrogen generating device 1 (step S160). Thereafter, the opening / closing control unit 32 opens the outlet of the hydrogen production apparatus 1 by opening the opening / closing valve 26 (step S170). In addition, the operation control unit 31 stops the system startup process (step S175). That is, the operation control unit 31 stops the operation of each device in the system. After the activation process is stopped in S175, the process shown in FIG. 3 ends. Thereafter, an inspection regarding the airtightness of the hydrogen production apparatus 1 may be performed.

On the other hand, if the pressure change amount ΔP is determined that the second threshold value _{P 2} is less than in S150, the abnormality detecting unit 35 detects the air-tightness of the abnormality of the opening and closing valve 26 of the outlet (step S180). Thereafter, the opening / closing control unit 32 opens the outlet of the hydrogen production apparatus 1 by opening the opening / closing valve 26 (step S190). Further, the operation control unit 31 stops the system startup process (step S195). That is, the operation control unit 31 stops the operation of each device in the system. After the activation process is stopped in S195, the process shown in FIG. 3 ends. Thereafter, an inspection regarding the airtightness of the on-off valve 26 may be performed.

  Next, operations and effects of the fuel cell system 100 and the abnormality detection method according to the present embodiment will be described.

  For example, when a hydrogen detector and a fuel cell stack are housed in a housing and a gas detector is provided in the housing to detect an abnormality, the gas detector detects if a certain amount of gas is not present in the housing. There is a problem that can not be. In addition, there is a problem that it is difficult to determine where there is an abnormality (it cannot be determined whether there is an abnormality in the hydrogen production apparatus or an abnormality in the fuel cell stack). In addition, although an abnormality such as gas exiting into the casing can be detected, an abnormality such as a valve failure that prevents gas from exiting into the casing cannot be detected.

  In addition, when the fuel cell system is stopped, after the temperature of the catalyst layer becomes equal to or lower than the decomposition temperature of the raw fuel gas, the reformer is sealed by sealing the raw fuel gas, and in this state, the temperature of the sealed space The pressure is detected over time, and the pressure drop speed based on the detection result is compared with the pressure drop speed calculated by calculation, thereby determining an abnormality in airtightness. However, in this method, abnormalities related to airtightness (damage such as cracks) may occur while the system is stopped. In such a case, there is a problem that the abnormality cannot be detected until the next operation is stopped. there were. In addition, when the most recent stop is an emergency stop due to a power failure or the like, the system is started without performing the abnormality detection process. That is, there is a problem that the next operation is performed in a state where there is an abnormality. Further, when the raw fuel is enclosed in the reformer at the time of stopping, coking to the reforming catalyst becomes a problem when the system is started in the next operation. Furthermore, in the detection method based on the pressure drop speed at the time of stopping, there may be a case where an abnormality relating to airtightness cannot be detected accurately. For example, the pressure drop rate changes greatly due to external factors such as the temperature and pressure of the supply gas and the temperature in the package (for example, the pressure drop rate is high in winter and slow in summer). It can be difficult. Further, depending on the degree of damage, there is a possibility that the pressure at the start of abnormality detection does not reach a predetermined pressure, and abnormality detection may not be performed accurately. In addition, since the reforming section is at a high temperature (high pressure) at the time of stoppage, the amount of gas emitted may increase when there is an abnormality.

In contrast, in the fuel cell system 100 according to the present embodiment, the outlet side of the hydrogen production apparatus 1 is closed by the on-off valve 26, and the airtightness is based on the pressure change ΔP when the raw fuel is supplied to the hydrogen production apparatus 1. Detecting abnormalities related to sex. When the reformed gas outlet side of the hydrogen production apparatus 1 is closed by the on-off valve 26 and the raw fuel is supplied to the hydrogen production apparatus 1, if there is no abnormality related to airtightness, on the upstream side of the on-off valve 26, Pressure increases. On the other hand, when there is an abnormality related to airtightness, the pressure increase is smaller than when there is no abnormality. Accordingly, the pressure change amount ΔP in the conditions, that the abnormality in advance set the first threshold value P ₁ as the value in the absence, the abnormality detecting unit 35, when the system is started, the pressure change amount ΔP but when the first threshold value P ₁ is smaller than it is possible to detect the abnormality relating to airtightness.

  In the fuel cell system 100 and the abnormality detection method according to the present embodiment, the abnormality detection unit 35 can detect an abnormality at the time of system startup, and therefore operates the fuel cell system 100 in a state where there is an abnormality related to airtightness. Can be prevented. Also, when the reforming is performed by closing the outlet side of the hydrogen production apparatus 1 at the time of starting the system, the pressure rises in a short time, so that an abnormality can be detected quickly, and there is a clear difference between the pressure when there is an abnormality and when there is no abnormality. Therefore, it is possible to accurately detect an abnormality. As described above, an abnormality relating to airtightness can be detected in a shorter time and more accurately.

  In the fuel cell system 100 according to the present embodiment, an abnormality relating to airtightness can be detected in a short time when the system is started. Therefore, even when there is an abnormality, the amount of gas that goes out can be reduced as much as possible. it can. Because it is an abnormality detection at the time of system start-up, no matter what stage of the previous operation, an abnormality can be detected immediately in the next operation, and the situation during the previous operation (for example, emergency stop) Regardless, abnormalities can be detected. Further, since it is not necessary to seal the raw fuel at the time of stopping, coking to the reforming catalyst does not occur.

Further, in the fuel cell system 100, the abnormality detecting unit 35 determines the pressure change amount [Delta] P, by comparing the second threshold value P ₂ is smaller than the first threshold value P _1, a portion of the abnormality relating to airtightness. When there is an abnormality related to airtightness, the pressure rise when the on-off valve 26 is closed and reforming is reduced, but the degree of the pressure rise is different depending on the location of the abnormality. Therefore, by comparing the pressure change amount ΔP and the second threshold value P _2, it is possible to determine an abnormality of the location. Thus, it is possible to efficiently perform repair after detecting an abnormality by specifying the abnormality and then detecting the abnormality.

  The fuel cell system 100 further includes a thermometer 27 that detects the temperature of the hydrogen production apparatus 1. The thermometer 27 detects the temperature after the start of temperature increase of the hydrogen production apparatus 1, and the abnormality detection unit 35 is detected by the thermometer 27 when the temperature is raised to a temperature at which the hydrogen production apparatus 1 can start reforming. An abnormality related to the supply of raw fuel is detected based on the temperature. This makes it possible to detect an abnormality related to the raw fuel before detecting an abnormality related to airtightness.

  The present invention is not limited to the embodiment described above.

  For example, the processing content shown in FIG. 4 may be executed instead of the processing content shown in FIG. In FIG. 3, reforming is started (step S100) after closing the outlet of the hydrogen production apparatus 1 (step S90), whereas in FIG. 4, hydrogen production is started after reforming is started (step S100). The exit of the apparatus 1 is closed (step S90). Further, an abnormality regarding the supply of reforming water is also determined between the start of reforming and the closing of the outlet. For other portions, FIG. 4 performs the same processing as FIG.

Specifically, after the reforming start of hydrogen production apparatus 1 (step S100), the abnormality detecting unit 35 determines the measured temperature T _C is to or smaller than reforming determination temperature T _H in S40 (Step S210). Note that reforming determination temperature T _H is the temperature that indicates that normal reforming water to the hydrogen production apparatus 1 is not supplied, an arbitrary value is set for such measurement spots temperature T _C. For example, if the temperature T _C was the temperature of the representative points of the reforming catalyst layer in the reformer unit 6, sets the temperature at which the normal endothermic reaction in the reforming catalyst layer does not occur as the modifying determination temperature T _H can do. If the temperature T _C was the temperature of the different measurement points, different modification determination temperature T _H is set. It is also possible to determine the modification determination temperature T _H of the temperature at a plurality locations. Note that the temperature Tc used for the abnormality detection of the reforming system in S210 may be determined using the same temperature Tc used for the abnormality detection of the raw fuel system in S50. The temperature Tc used for the determination of S50 may be different from the temperature Tc used for the determination of S210.

In S210, when the temperature T _C is determined to be greater than the reforming determination temperature T _H, the abnormality detecting unit 35 determines whether or not a predetermined time from the reforming start has elapsed (step S220). As the predetermined time, when there is no abnormality in the fuel cell system 100, it is possible to set the time required for the following reforming determination temperature T _H and endothermic reaction starts from the reforming start. The predetermined time can be set to 0 to 30 minutes. If it is determined in S220 that the predetermined time has not elapsed, the process of S210 is performed again. On the other hand, when it is determined in S220 that the predetermined time has elapsed, the abnormality detection unit 35 detects an abnormality in the reforming water system (step S230). The fact that the temperature of the hydrogen production apparatus 1 is high even after a predetermined time has passed despite the control of supplying the reforming water to the reforming unit 6 means that the reforming water system has failed and the endothermic reaction has not occurred. It is estimated that it has not happened. When an abnormality is detected in S230, the operation control unit 31 stops the system startup process (step S240). That is, the operation control unit 31 stops the operation of each device in the system. After the activation process is stopped in S240, the process shown in FIG. 4 ends. Thereafter, the raw material system in the fuel cell system 100 may be inspected.

  As described above, the abnormality detection unit 35 detects an abnormality related to the supply of reforming water based on the temperature detected by the thermometer 27 when the reforming in the hydrogen production apparatus 1 is started. This makes it possible to detect an abnormality related to the supply of reforming water before detecting an abnormality related to airtightness. Even when the control process of FIG. 3 is employed, a process for detecting an abnormality related to the supply of reforming water by performing the processes of S210 to S240 shown in FIG. 4 immediately after the start of reforming. May be performed. However, in the control process of FIG. 3, the pressure rises earlier than when the abnormality of the reforming water system is detected, so there is a possibility that sufficient time cannot be secured for detecting the abnormality of the reforming system. Therefore, when detecting an abnormality in the reforming system, it is more preferable to employ the control process of FIG.

  Further, in the present invention, it is sufficient that at least the presence or absence of an airtight abnormality of the fuel cell system 100 can be determined, and the abnormality detection process related to the supply of raw fuel and the abnormality detection process related to the supply of reforming water may be omitted. In addition, the determination process (determination using the second threshold value) of an abnormal portion related to airtightness may be omitted.

  DESCRIPTION OF SYMBOLS 1 ... Hydrogen production apparatus, 2 ... Desulfurization part, 6 ... Reformation part, 7 ... Shift reaction part, 8 ... Selective oxidation reaction part, 20 ... Fuel cell stack, 23 ... Pressure gauge (pressure detection part), 26 ... Open / close valve (Open / close unit), 27 ... thermometer (temperature detection unit), 30 ... control unit, 31 ... operation control unit, 32 ... open / close control unit, temperature acquisition unit, 34 ... pressure acquisition unit, 35 ... abnormality detection unit, 100 ... Fuel cell system.

Claims (4)

A hydrogen production unit that generates a reformed gas containing hydrogen using raw fuel;
A fuel cell stack that generates electricity using the reformed gas generated by the hydrogen production unit;
An open / close section that opens and closes the outlet side of the reformed gas of the hydrogen production section;
A pressure detection unit for detecting pressure upstream from the opening and closing unit;
An anomaly detection unit for detecting an anomaly in the system,
The abnormality detection unit has a value based on a pressure detected by the pressure detection unit when the open / close unit is closed and the raw fuel is supplied to the hydrogen production unit when the system is started up. When it is smaller than the threshold, an abnormality related to airtightness is detected ,
The abnormality detection unit is a fuel cell system that determines an abnormality location related to airtightness by comparing a value based on the pressure with a second threshold value that is smaller than the first threshold value . A temperature detection unit for detecting the temperature of the hydrogen production unit;
2. The fuel cell system according to claim 1, wherein the abnormality detection unit detects an abnormality related to supply of raw fuel based on a temperature detected by the temperature detection unit after the start of temperature increase in the hydrogen production unit. A temperature detection unit for detecting the temperature of the hydrogen production unit;
The fuel cell system according to claim 1 or 2 , wherein the abnormality detection unit detects an abnormality related to the supply of reforming water based on the temperature detected by the temperature detection unit after the start of reforming in the hydrogen production unit. . A hydrogen production unit that generates a reformed gas containing hydrogen using raw fuel;
An abnormality detection method for detecting an abnormality of a fuel cell system comprising: a fuel cell stack that generates electric power using the reformed gas generated by the hydrogen production unit,
A closing step of closing an outlet side of the reformed gas of the hydrogen production unit with an opening and closing unit;
A pressure detecting step for detecting pressure upstream from the opening and closing unit;
An anomaly detection process for detecting an anomaly in the system,
In the pressure detection step, when the system is started, the closing step is executed, and the pressure when the raw fuel is supplied to the hydrogen production unit is detected,
In the abnormality detection step ,
When the value based on the pressure is smaller than the first threshold, an abnormality related to airtightness is detected ,
An abnormality detection method for determining a location of an abnormality related to airtightness by comparing a value based on the pressure with a second threshold value smaller than the first threshold value .

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