JP5577682B2 - Fuel cell system - Google Patents

Description

The present invention relates to a fuel cell system in which a hydrogen generator that generates hydrogen-rich fuel gas from a raw material and steam using a reforming catalyst and a fuel cell are integrated .

In order to satisfactorily operate the hydrogen generator, it is preferable to detect the gas leakage from the flow path. In particular, a gas leakage portion in a range that forms a sealed section when the apparatus is shut down causes air to be sucked in from the outside due to a pressure drop accompanying a drop in internal temperature when the apparatus is shut down, thereby deteriorating the catalyst.

The fuel cell system which performs a conventional gas leak detection, there is performs gas leak detection by the pressure drop of the sealed space including the hydrogen generator (for example, see Patent Document 1). Further, the gas detection sensor provided in a package deployed hydrogen generator, was also performs gas leak detection leaking inside the package from the hydrogen generator (for example, see Patent Document 2). Figure 5 shows a fuel cell system using the conventional hydrogen generator described in Patent Document 1.

In the fuel cell system shown in FIG. 5, a hydrogen generator 101 that generates fuel gas from raw material gas and water vapor, a burner 102 that heats the hydrogen generator, a fuel cell 103 that generates power using fuel gas and air, A source gas channel 104 for supplying source gas to the hydrogen generator, a fuel gas channel 105 for supplying fuel gas generated to the fuel cell, and a fuel gas bypass channel 106 for bypassing the generated fuel gas to the fuel cell; A fuel off-gas passage 107 for supplying the fuel gas discharged from the fuel cell to the burner, and a shutoff valve 108 for supplying and shutting off the source gas,
A shutoff valve 109 for conducting / shutting off the fuel gas to and from the fuel gas bypass passage, a shutoff valve 110 for feeding / shutting off the fuel gas to / from the fuel cell, and a discharge / shutoff of the fuel gas from the fuel cell. The shut-off valve 111 and the pressure sensor 112 for detecting the pressure of the hydrogen generator were provided. When the gas leak detection of the hydrogen generator is performed, the shut-off valve 108 is opened and the shut-off valves 109, 110, 111 are closed. The source gas is pumped by a pump (not shown), and pressure is applied to the hydrogen generator 101 and the gas flow channel upstream of the shutoff valves 109 and 110. When the pressure of the pressure sensor 112 becomes higher than a predetermined value, the pump (not shown) is stopped, the shutoff valve 108 is closed, and the hydrogen generator 101 surrounded by the shutoff valves 108, 109, 110 and the gas flow path are included. Gas leakage detection is performed by setting the section to a sealed section and monitoring the pressure drop for a predetermined time (for example, 5 minutes).

  The leak detection operation is performed before the fuel cell system is shipped, immediately before the start of the fuel cell system, when pipes and parts are replaced after shipment, when pipes and parts are replaced after shipment, and when the fuel cell system is maintained. Is disclosed.

JP 2008-108446 A (page 7-16, FIGS. 1-4) Japanese Patent Laying-Open No. 2003-229148 (page 6-9, FIG. 1-3)

However, since the gas leakage is detected by the pressure drop in the conventional configuration, the gas pressure cannot be detected because the internal pressure is also lowered when the temperature of the hydrogen generator is continuously lowered. Since temperature generator 101 inside of the hydrogen when the general hydrogen generator continues hydrogen generation is 500 ° C. to 800 ° C. and a high temperature, the hydrogen generator to a room temperature of about 30 ° C. When stopping the hydrogen generator Although the temperature is lowered, there is a problem that gas leak detection cannot be performed during this time. Regarding the gas leakage during this period, the gas leakage leaked from the hydrogen generator into the package can be detected by the gas detection sensor described in Patent Document 2, but on the other hand, the downstream fuel gas flow via the shutoff valve 109 is detected. The gas leak that leaks into the road is discharged outside the system through the burner 102 that has stopped combustion, and therefore gas leak detection cannot be performed. That is, stop the hydrogen generator hydrogen generated in until the temperature drops to normal temperature of about 30 ° C., it is impossible to detect the gas leakage due to internal leakage downstream of the shut-off valve from the hydrogen generator , Had a problem of.

The present invention is the one that solves the conventional problem, a fuel cell system capable of detecting the gas leakage into the downstream flow path from the hydrogen generator even when the internal pressure of the hydrogen generator is lowered The purpose is to provide.

In order to solve the above-described conventional problems, the first aspect of the present invention includes a hydrogen generator that generates a hydrogen-rich fuel gas using a source gas, a burner that heats the hydrogen generator, and the source gas. and from the raw material supply source gas flow path for supplying the hydrogen generator, and the raw material gas shutoff valve disposed in the feed gas passage, and the fuel gas channel for discharging the fuel gas from the hydrogen generator, the a fuel gas shutoff valve for Tsuryu or blocking the fuel gas discharged from the hydrogen generator provided in the fuel gas flow passage is branched from the upstream said fuel gas passage from the fuel gas shutoff valve the fuel gas to the burner A second fuel gas flow path for supplying fuel, a second fuel gas cutoff valve provided in the second fuel gas flow path for passing or blocking the fuel gas discharged from the hydrogen generator, and the fuel gas cutoff valve The fuel gas further downstream A fuel cell for generating electric power by using the connected hydrogen and oxygen into the flow path, residual fuel gas discharged from the fuel cell without being used for power generation in the fuel cell
A third fuel gas passage for discharging the gas to the second fuel gas passage downstream of the second fuel gas shutoff valve, and a residual fuel gas provided in the third fuel gas passage and discharged from the fuel cell a third fuel gas shutoff valve for Tsuryu or block, and gas leak detection means for detecting a gas leakage is provided in the second fuel gas flow path downstream of the confluence between the third fuel gas flow path, said the opening and closing of the valve of the raw material gas shutoff valve and the fuel gas shutoff valve and the second fuel gas shutoff valve and the third fuel gas shutoff valve is controlled, the said fuel gas cutoff valve by the gas leak detection means first A fuel gas shut-off valve and a control unit for detecting gas leak due to internal leak from the third fuel gas shut-off valve , wherein the control unit detects gas leak due to internal leak from the second fuel gas shut-off valve. When operating, the hydrogen production The fuel gas cutoff valve, the second fuel gas cutoff valve, the second fuel gas cutoff valve, the second fuel gas cutoff valve, the second fuel gas cutoff valve, the second fuel gas cutoff valve, A fuel cell that opens the source gas shut-off valve in a state in which the third fuel gas shut-off valve is shut off, and determines whether or not there is a gas leak due to an internal leak from the second fuel gas shut-off valve by the gas leak detection means System .

With this configuration, even when the internal pressure of the hydrogen generator is lowered, controls the opening and closing of the valve of the raw material gas shutoff valve and the fuel gas shutoff valve and the second fuel gas shutoff valve and the third fuel gas shutoff valve Then, the presence or absence of gas leakage due to internal leakage from the fuel gas cutoff valve, the second fuel gas cutoff valve, and the third fuel gas cutoff valve provided in the downstream flow path from the hydrogen generator can be detected by the gas leakage detection means. it can.

According to the fuel cell system of the present invention, even when the internal pressure of the hydrogen generator is lowered, the raw material gas shutoff valve and the fuel gas shutoff valve and the second fuel gas shutoff valve and the third fuel gas shutoff valve by controlling the opening and closing of the valve, the presence or absence of gas leakage due to internal leakage from the fuel gas shutoff valve and the second fuel gas shutoff valve and the third fuel gas shutoff valve provided on the downstream channel from the hydrogen generator by the gas leakage detection means Can be detected.

Block diagram of a hydrogen generator in Reference Example 1 of the present invention Block diagram of a hydrogen generator in Reference Example 2 of the present invention Block diagram of a hydrogen generator in Reference Example 3 of the present invention 1 is a block diagram of a fuel cell system according to Embodiment 1 of the present invention. Block diagram of a fuel cell system using a conventional hydrogen generator

The first present invention provides a hydrogen generator for generating hydrogen-rich fuel gas, a burner for heating the hydrogen generator, the hydrogen generator of the material gas from the raw material supply source by using the raw material gas the raw material gas flow path, and the raw material gas shutoff valve disposed in the feed gas passage, and the fuel gas channel for discharging the fuel gas from the hydrogen generator, the hydrogen generator is provided in the fuel gas flow passage A fuel gas shut-off valve for passing or shutting off the fuel gas discharged from the fuel gas, a second fuel gas flow path for branching from the fuel gas flow path upstream from the fuel gas shut-off valve and supplying fuel gas to the burner; A second fuel gas shut-off valve provided in the second fuel gas passage and configured to pass or shut off the fuel gas discharged from the hydrogen generator; and connected to the fuel gas passage downstream of the fuel gas shut-off valve. Using hydrogen and oxygen And a third fuel that discharges residual fuel gas discharged from the fuel cell without being used for power generation to the second fuel gas flow path downstream from the second fuel gas shut-off valve Junction point of the third fuel gas channel, a gas channel, a third fuel gas cutoff valve that is provided in the third fuel gas channel and allows the residual fuel gas discharged from the fuel cell to flow or shut off more and gas leak detection means for detecting a gas leakage is provided downstream the second fuel gas flow path, the third fuel gas cutoff and the raw material gas shutoff valve and the fuel gas shutoff valve and the second fuel gas shutoff valve Control the opening and closing of the valve with the valve , the gas leak detection means
A control unit for detecting gas leakage due to internal leakage from the fuel gas cutoff valve, the second fuel gas cutoff valve, and the third fuel gas cutoff valve , wherein the control unit includes the second fuel gas cutoff valve. When performing a gas leak detection operation due to an internal leak from the valve, the raw material gas cutoff valve, the fuel gas cutoff valve, the second fuel gas cutoff valve, and the third fuel gas cutoff when the hydrogen generator is shut down After the valve is shut off, the material gas shut-off valve is opened with the fuel gas shut-off valve, the second fuel gas shut-off valve and the third fuel gas shut-off valve shut off, and the gas leak detection means causes the first (2) A fuel cell system that determines the presence or absence of gas leakage due to internal leakage from a fuel gas shut-off valve .

With this configuration, even when the internal pressure of the hydrogen generator is lowered, controls the opening and closing of the valve of the raw material gas shutoff valve and the fuel gas shutoff valve and the second fuel gas shutoff valve and the third fuel gas shutoff valve Then, the presence or absence of gas leakage due to internal leakage from the fuel gas cutoff valve, the second fuel gas cutoff valve, and the third fuel gas cutoff valve provided in the downstream flow path from the hydrogen generator can be detected by the gas leakage detection means. it can.

Further, according to a second aspect of the present invention, the control unit according to the first aspect of the present invention performs a gas leakage detection operation due to an internal leak from the second fuel gas cutoff valve, thereby causing an internal leak from the second fuel gas cutoff valve. After determining that there is no gas leak due to the above, the raw gas shut-off valve and the third fuel gas shut-off valve are opened with the fuel gas shut-off valve and the second fuel gas shut-off valve shut off, and the gas leak detecting means This is a fuel cell system that determines the presence or absence of gas leakage due to internal leakage from the fuel gas shutoff valve .

According to this configuration, the control unit can accurately detect a gas leak due to an internal leak from the fuel gas cutoff valve .

According to a third aspect of the present invention, the control unit according to the first aspect of the present invention performs a gas leak detection operation based on an internal leak from the second fuel gas shut-off valve, thereby causing an internal leak from the second fuel gas shut-off valve. After judging that there is no gas leakage due to the above, the raw gas cutoff valve and the fuel gas cutoff valve are opened with the second fuel gas cutoff valve and the third fuel gas cutoff valve shut off, and the gas leakage detection means The fuel cell system for determining whether or not there is a gas leak due to an internal leak from the third fuel gas shut-off valve .

According to this configuration, the control unit can accurately detect a gas leak due to an internal leak from the third fuel gas cutoff valve .

According to a fourth aspect of the present invention, in any one of the first to third aspects of the present invention , the gas leak detection means includes an igniter that performs an ignition operation of the burner, and a flame of the burner. A fuel cell system using a flame detector for detection, wherein the control unit causes the igniter to perform an ignition operation and whether or not flame detection is performed by the flame detector .

According to this configuration, the igniter can be ignited, and gas leakage can be detected based on the presence or absence of flame detection by the flame detector. Further, the igniter and the flame detector as the gas leakage detection means also serve as the igniter in the burner and the flame detector in the burner during the fuel gas generation operation, so that further cost reduction is achieved. be able to.

Reference examples and embodiments of the present invention will be described below with reference to the drawings. Note that the present invention is not limited to the embodiments.

( Reference Example 1)
FIG. 1 is a block diagram showing a configuration of a hydrogen generator in Reference Example 1 of the present invention.

The hydrogen generator in this reference example includes a hydrogen generator 1 that generates a fuel gas by steam reforming a hydrocarbon-based source gas such as city gas or propane gas using a catalyst, and a source gas supply. A raw material gas flow path 2 for supplying a raw material gas from a source to the hydrogen generator 1, a raw material gas shut-off valve 3 for supplying and shutting off the raw material gas to the hydrogen generator 1, and a hydrogen gas from a steam supply source for generating hydrogen A steam flow path 4 that supplies the steam generator 1, a steam shut-off valve 5 that feeds and shuts off steam to the hydrogen generator 1, and a hydrogen-rich fuel gas generated by steam reforming in the hydrogen generator 1 are discharged. A fuel gas flow path 6, a fuel gas shutoff valve 7 for discharging and shutting off fuel gas from the hydrogen generator 1, a burner 8 for heating a catalyst inside the hydrogen generator 1, and a combustion gas from a combustion gas supply source Is supplied to the burner 8 A combustion gas flow path 9, a combustion gas cutoff valve 10 that supplies and shuts off combustion gas to the burner 8, a temperature sensor 11 that detects the temperature of the reforming catalyst, and a gas provided downstream of the fuel gas cutoff valve 7. The gas leak detector 12 which detects a leak, the air blower 13 which supplies the air which dilutes leak gas at the time of gas leak, and the control part 14 which controls a series of operation regarding a gas leak detection are provided.

The gas leak detector 12 as a constituent member in this reference example is an example of a specific implementation of the gas leak detection means in the present invention. Moreover, the air blower 13 as a structural member in this reference example is an example of a concrete implementation of the diluting means in the present invention. As the blower 13, a fan, a blower, a pump, or the like can be used.

First, specific operation regarding the fuel gas generation of the hydrogen generator in this reference example will be described.

  In the hydrogen generator shown in FIG. 1, after the raw material gas shut-off valve 3 is opened, the city gas or propane supplied from the raw material supply source is removed by a desulfurizer (not shown) containing odorous components. The raw material gas is supplied to the hydrogen generator 1 through the raw material gas passage 2. The steam necessary for the reforming reaction in the hydrogen generator 1 is supplied from the steam supply source to the hydrogen generator 1 through the steam channel 4 by opening the steam shutoff valve 5. The hydrogen generator 1 mixes the supplied raw material gas and steam, and then steam reforms using a catalyst to generate a hydrogen-rich fuel gas. The generated hydrogen-rich fuel gas is discharged out of the system of the hydrogen generator through the fuel gas flow path 6 by opening the fuel gas cutoff valve 7. The discharged fuel gas can be supplied to a hydrogen utilization device such as a fuel cell that generates power using hydrogen (not shown). Further, the heat necessary for generating the fuel gas in the hydrogen generator 1 is generated by supplying the combustion gas from the combustion gas supply source to the burner 8 through the combustion gas passage 9 and burning it by opening the combustion gas cutoff valve 10. Thus, the combustion heat is supplied to the hydrogen generator 1, and the temperature rise / temperature maintenance of the hydrogen generator 1 is performed using the temperature detection value from the temperature sensor 11.

Next, a specific operation will be described with respect to gas leak detection of the hydrogen generator in this reference example .

The control unit 14 shuts off the raw material gas shut-off valve 3, the water vapor shut-off valve 5, and the combustion gas shut-off valve 10 and shuts off the supply of the raw material gas, water vapor, and combustion gas, respectively, when the hydrogen generation operation in the hydrogen generator 1 is stopped. At the same time, the fuel gas shut-off valve 7 is shut off and the hydrogen generator 1 is sealed, thereby preventing air from flowing in from the downstream of the fuel gas flow path 6 and the like. Further, the downstream side of the fuel gas flow path 6 is separated from the hydrogen utilization device and is opened to the atmosphere. The controller 14 diverts the temperature detection value from the temperature sensor 11 that detects the temperature rise and temperature maintenance of the hydrogen generator 1 during the hydrogen generation operation, so that the temperature of the hydrogen generator 1 is changed to the catalyst by the raw material gas. When the temperature falls below a predetermined temperature at which carbon deposition does not occur (for example, 500 ° C.), the raw material gas shutoff valve 3 is opened with the fuel gas shutoff valve 7 shut off, the raw material gas flow path 2, the hydrogen generator 1, and the fuel gas shutoff. The pressure in the section including the fuel gas passage 6 upstream from the valve 7 is set to a pressure equivalent to that of the source gas supply source. On the other hand, the control unit 14 monitors the detection signal from the gas leak detector 12 and detects a gas leak due to an internal leak from the fuel gas shutoff valve 7 when the detection signal detects a value that can be determined as “gas leak”. To do. Further, when detecting a gas leak, the control unit 14 closes the raw material gas shut-off valve 3, operates the blower 13, sufficiently dilutes the leaked gas to a concentration that does not ignite, and discharges it outside the system of the hydrogen generator. When the detection signal detects a value that can be determined as “no gas leak”, the material gas cutoff valve 3 is closed and the gas leak detection operation is terminated.

When the configuration of the hydrogen generator in this reference example is taken, the control unit 14 is connected to the gas leak detector 12 from the gas leak detector 12 even during a period in which the internal pressure drop occurs due to the temperature drop of the hydrogen generator 1 after the hydrogen generation operation is stopped. By monitoring the detection signal, opening the raw material gas shut-off valve 3 brings the sealed section including the hydrogen generator 1 to a pressure (positive pressure) equivalent to that of the raw material gas supply source, and shuts off the fuel gas equivalent to the atmospheric pressure. Since a pressure difference can be given between the downstream of the valve 7, it is possible to detect a gas leak due to an internal leak from the fuel gas cutoff valve 7 based on the differential pressure.

In the configuration of the hydrogen generator in this reference example, the blown air from the blower 13 that supplies the air that dilutes the leaked gas when the gas leaks is supplied to the fuel gas passage 6 downstream from the fuel gas shutoff valve 7. As a result, when the control unit 14 detects a gas leak, the blower 13 is operated to supply the blown air to the fuel gas passage 6 downstream from the fuel gas shutoff valve 7 and dilute the leaked gas with air. Therefore, it is possible to sufficiently dilute the leaked gas to a concentration that does not ignite and discharge the leaked gas outside the system of the hydrogen generator.

In the gas leak detection in this reference example , the control unit has performed a series of operations for gas leak detection based on the temperature detection value from the temperature sensor 11, but this is not the only case, and from a stop obtained experimentally in advance. A series of operations may be performed according to the passage of a predetermined time based on the relationship between the passage of time and the temperature drop. Further, the above-described gas leak detection operation may be performed a plurality of times during the period from when the hydrogen generator stops hydrogen generation until the temperature drops to a room temperature of about 30 ° C.

In the present reference example , the blower 13 is used as the diluting means. However, the present invention is not limited thereto, and the diluting with an inert gas may be performed using an inert gas cylinder such as nitrogen or argon as the diluting means.

( Reference Example 2)
FIG. 2 is a block diagram showing the configuration of the hydrogen generator in Reference Example 2 of the present invention.

In FIG. 2, the same components as those in FIG. Further, the specific operation relating to the fuel gas generation of the hydrogen generator in the present reference example is the same as that of the reference example 1, and the description thereof is omitted.

Compared with the hydrogen generator in Reference Example 1, the hydrogen generator in this reference example performs an ignition operation by high-pressure discharge instead of the gas leak detector 12 which is an example of a specific implementation of the gas leak detector. The igniter 21 is different from the igniter 21 in that a flame in the vicinity of the igniter 21 is detected by an ionic current.

The igniter 21 and the frame rod 22 as constituent members in this reference example are examples of specific implementations of the igniter and the flame detector in the present invention, respectively.

Next, a specific operation will be described with respect to gas leak detection of the hydrogen generator in this reference example .

In the hydrogen generator shown in FIG. 2, the control unit 14 shuts off the raw material gas shutoff valve 3, the water vapor shutoff valve 5, and the combustion gas shutoff valve 10 when the hydrogen generator 1 is stopped in the hydrogen generator 1. The supply of water vapor and combustion gas is shut off, the fuel gas shutoff valve 7 is shut off, and the hydrogen generator 1 is sealed to prevent the inflow of air from the downstream of the fuel gas flow path 6 and the like. Further, the downstream side of the fuel gas flow path 6 is separated from the hydrogen utilization device and is opened to the atmosphere. The controller 14 diverts the temperature detection value from the temperature sensor 11 that detects the temperature rise and temperature maintenance of the hydrogen generator 1 during the hydrogen generation operation, so that the temperature of the hydrogen generator 1 is changed to the catalyst by the raw material gas. When the temperature falls below a predetermined temperature at which carbon deposition does not occur (for example, 500 ° C.), the raw material gas shutoff valve 3 is opened with the fuel gas shutoff valve 7 shut off, the raw material gas flow path 2, the hydrogen generator 1, and the fuel gas shutoff. The pressure in the section including the fuel gas passage 6 upstream from the valve 7 is set to a pressure equivalent to that of the source gas supply source.

  On the other hand, the control unit 14 discharges the igniter 21 at a high pressure to perform an ignition operation, and monitors the detection signal of the frame rod 22. Then, a gas leak due to an internal leak from the fuel gas shutoff valve 7 is detected. Further, when detecting a gas leak, the control unit 14 closes the raw material gas shut-off valve 3, operates the blower 13, sufficiently dilutes the leaked gas to a concentration that does not ignite, and discharges it outside the system of the hydrogen generator. When the detection signal detects a value that can be determined as “no flame”, it is determined as “no gas leak”, the material gas cutoff valve 3 is closed, and the gas leak detection operation is terminated.

If the configuration of the hydrogen generator in the present reference example is taken, the control unit 14 is caused by high-pressure discharge to the igniter 21 even during a period in which the internal pressure drop occurs due to the temperature drop of the hydrogen generator 1 after the hydrogen generation operation is stopped. By monitoring the ignition operation and the presence / absence of a flame based on a detection signal from the frame rod 22, the raw material gas shut-off valve 3 is opened to open the sealed section including the hydrogen generator 1 at the same pressure (positive pressure) as the raw material gas supply source. ), And a pressure difference can be given between the downstream side of the fuel gas cutoff valve 7 which is equivalent to the atmospheric pressure, and therefore gas leakage due to internal leak from the fuel gas cutoff valve 7 can be detected by the differential pressure.

In the configuration of the hydrogen generator in this reference example, the blown air from the blower 13 that supplies the air that dilutes the leaked gas when the gas leaks is supplied to the fuel gas passage 6 downstream from the fuel gas shutoff valve 7. As a result, when the control unit 14 detects a gas leak, the blower 13 is operated to supply the blown air to the fuel gas passage 6 downstream from the fuel gas shutoff valve 7 and dilute the leaked gas with air. Therefore, it is possible to sufficiently dilute the leaked gas to a concentration that does not ignite and discharge the leaked gas outside the system of the hydrogen generator.

In the gas leak detection in this reference example , the control unit has performed a series of operations for gas leak detection based on the temperature detection value from the temperature sensor 11, but this is not the only case, and from a stop obtained experimentally in advance. A series of operations may be performed according to the passage of a predetermined time based on the relationship between the passage of time and the temperature drop. Further, the above-described gas leak detection operation may be performed a plurality of times during the period from when the hydrogen generator stops hydrogen generation until the temperature drops to a room temperature of about 30 ° C.

In this reference example , the blower 13 is used as an example of a specific implementation of the diluting means. However, the present invention is not limited thereto, and an inert gas cylinder such as nitrogen or argon is used as the diluting means, and dilution with an inert gas is performed. You may do it.

In this reference example , the igniter 21 that performs the ignition operation by high-pressure discharge is used as an example of the specific implementation of the igniter. However, the present invention is not limited to this. Good. In addition, as a specific example of the implementation of the flame detector, the flame rod 22 that detects the flame by the ionic current is used. However, the present invention is not limited to this, and a flame temperature sensor that detects a temperature rise due to the flame may be used.

( Reference Example 3)
FIG. 3 is a block diagram showing a configuration of the hydrogen generator in Reference Example 3 of the present invention as a modification of the hydrogen generator in Reference Example 2 of the present invention. 3, the same components as those in FIG. 2 are denoted by the same reference numerals, and description thereof is omitted.

Compared with the hydrogen generator in Reference Example 2, the hydrogen generator in this reference example branches from the fuel gas flow path 6 upstream from the fuel gas shutoff valve 7 and supplies the fuel gas to the burner 8. The igniter 21 and the frame rod are provided with a passage 31, a second fuel gas shutoff valve 32 for supplying and shutting off fuel gas flowing through the second fuel gas passage 31, and a fan 33 for supplying air to the burner 8. The difference is that 22 is provided in the burner 8.

First, specific operation regarding the fuel gas generation of the hydrogen generator in this reference example will be described.

  In the hydrogen generator shown in FIG. 3, the source gas cutoff valve 3 and the second fuel gas cutoff valve 32 are opened, and the fuel gas cutoff valve 7 is closed, so that the city gas or propane supplied from the raw material supply source is contained. After the odorous component to be removed is removed by a desulfurizer (not shown), the raw gas is supplied to the hydrogen generator 1 through the raw material gas passage 2. The raw material gas supplied to the hydrogen generator 1 flows through the hydrogen generator 1 and is discharged into the fuel gas flow path 6 in the raw material gas state. The discharged source gas is supplied to the burner 8 through the fuel gas channel 6 and the second fuel gas channel 31. At the same time, in the burner 8, the igniter 21 is operated as an ignition operation in the burner 8, and combustion air is supplied by the fan 33. By detecting the flame formed in the burner 8 by the ignition operation by the frame rod 22, stable combustion in the burner 8 is monitored. When the ignition operation is completed, the igniter 21 stops. When the temperature detected by the temperature sensor 11 by combustion of the raw material gas in the burner 8 is raised to a temperature at which reforming reaction is possible (for example, 350 ° C.), by opening the steam shut-off valve 5, a steam supply source To the hydrogen generator 1 through the water vapor channel 4. The hydrogen generator 1 mixes the supplied raw material gas and steam, and then steam reforms using a catalyst to generate a hydrogen-rich fuel gas. The generated hydrogen-rich fuel gas is supplied to the burner 8 through the fuel gas flow path 6 and the second fuel gas flow path 31 and burned, thereby generating power using hydrogen (not shown). The temperature is raised to a temperature at which sufficient fuel gas can be supplied to a hydrogen-using device such as the above. When it is detected that the temperature detected by the temperature sensor 11 has risen to a temperature at which sufficient fuel gas can be supplied to the hydrogen utilization device, the fuel gas cutoff valve 7 is opened and the second fuel gas cutoff valve 32 is opened. By closing, the fuel gas is supplied to the hydrogen utilization device. At the same time, the combustion gas shut-off valve 10 is opened, the combustion gas from the combustion gas supply source is supplied to the burner 8 through the combustion gas passage 9 and burned, and the temperature of the hydrogen generator 1 is maintained using the temperature detection value from the temperature sensor 11. To implement.

Next, a specific operation will be described with respect to gas leak detection of the hydrogen generator in this reference example .

The control unit 14 shuts off the raw material gas shut-off valve 3, the water vapor shut-off valve 5, and the combustion gas shut-off valve 10 and shuts off the supply of the raw material gas, water vapor, and combustion gas, respectively, when the hydrogen generation operation in the hydrogen generator 1 is stopped. At the same time, the fuel gas shut-off valve 7 and the second fuel gas shut-off valve 32 are shut off, and the hydrogen generator 1 is sealed to prevent air from flowing in from the downstream of the second fuel gas passage 31 and the like. The controller 14 diverts the temperature detection value from the temperature sensor 11 that detects the temperature rise and temperature maintenance of the hydrogen generator 1 during the hydrogen generation operation, so that the temperature of the hydrogen generator 1 is changed to the catalyst by the raw material gas. When the temperature is lower than a predetermined temperature at which carbon deposition does not occur (for example, 500 ° C.), the source gas cutoff valve 3 is opened with the fuel gas cutoff valve 7 and the second fuel gas cutoff valve 32 shut off, and the source gas flow path 2, hydrogen The pressure in the section including the generator 1 and the fuel gas passage 6 and the second fuel gas passage 31 upstream from the fuel gas cutoff valve 7 and the second fuel gas cutoff valve 32 is set to the same pressure as the source gas supply source. . On the other hand, the control unit 14 discharges the igniter 21 provided in the burner 8 with a high pressure to perform an ignition operation. When detected, it is determined that “there is a gas leak”, and a gas leak due to an internal leak from the second fuel gas cutoff valve 32 is detected. Further, when detecting a gas leak, the control unit 14 closes the raw material gas shut-off valve 3, operates the fan 33, sufficiently dilutes the leaked gas to a concentration that does not ignite, and discharges it from the burner 8 to the outside of the hydrogen generator. To do. When the detection signal detects a value that can be determined as “no flame”, it is determined as “no gas leak”, the material gas cutoff valve 3 is closed, and the gas leak detection operation is terminated.

If the configuration of the hydrogen generator in the present reference example is taken, the control unit 14 is caused by high-pressure discharge to the igniter 21 even during a period in which the internal pressure drop occurs due to the temperature drop of the hydrogen generator 1 after the hydrogen generation operation is stopped. By monitoring the ignition operation and the presence / absence of a flame based on a detection signal from the frame rod 22, the raw material gas shut-off valve 3 is opened to open the sealed section including the hydrogen generator 1 at the same pressure (positive pressure) as the raw material gas supply source. ), And a pressure difference can be given between the downstream of the second fuel gas shutoff valve 32, which is equivalent to the atmospheric pressure, so that a gas leak due to an internal leak from the second fuel gas shutoff valve 32 is detected by the differential pressure. Can do. Further, since the igniter 21 and the frame rod 22 also serve as an igniter in the burner 8 and a flame detector in the burner 8 during the fuel gas generation operation, in addition to the effects described above, further cost reduction is achieved. Can be planned.

Further, in the configuration of the hydrogen generator in the present reference example , the controller 14 is configured to supply the blower air from the fan 33 that supplies air for diluting the leaked gas to the burner 8 when the gas leaks, so that the control unit 14 prevents the gas leak. When detected, the blower air can be supplied to the burner 8 by operating the fan 33, and the leaked gas can be diluted with air, so that the leaked gas is sufficiently diluted to a concentration that does not ignite and hydrogen is generated from the burner 8. It can be discharged out of the system. Further, since the fan 33 also serves as combustion air supply means for supplying combustion air in the burner 8 during the fuel gas generation operation, it is possible to further reduce the cost in addition to the above-described effects.

In the gas leak detection in this reference example , the control unit has performed a series of operations for gas leak detection based on the temperature detection value from the temperature sensor 11, but this is not the only case, and from a stop obtained experimentally in advance. A series of operations may be performed according to the passage of a predetermined time based on the relationship between the passage of time and the temperature drop. Further, the above-described gas leak detection operation may be performed a plurality of times during the period from when the hydrogen generator stops hydrogen generation until the temperature drops to a room temperature of about 30 ° C.

In this reference example , the igniter 21 that performs the ignition operation by high-pressure discharge is used as an example of the specific implementation of the igniter. However, the present invention is not limited to this. Good. In addition, as a specific example of the implementation of the flame detector, the flame rod 22 that detects the flame by the ionic current is used. However, the present invention is not limited to this, and a flame temperature sensor that detects a temperature rise due to the flame may be used.

(Embodiment 1 )
Figure 4 is a block diagram showing a configuration of a fuel cell system that put the first embodiment of the present invention. 4, the same components as those in FIG. 3 are denoted by the same reference numerals, and description thereof is omitted.

The fuel cell system in the present embodiment is a fuel cell that generates power using hydrogen and oxygen connected to the fuel gas flow path 6 downstream from the fuel gas shutoff valve 7 as compared with the hydrogen generator in Reference Example 3. 41, a third fuel gas passage 42 for discharging residual fuel gas not used for power generation in the fuel cell 41 to the second fuel gas passage 31 downstream from the second fuel gas shut-off valve 32, and a third fuel gas The fuel gas or the residual fuel gas is supplied to the second fuel gas passage 31 after joining the third fuel gas passage 42 and the third fuel gas cutoff valve 43 for discharging / blocking the residual fuel gas from the passage 42. A difference is that a fourth fuel gas cutoff valve 44 that supplies and shuts off the burner 8 is provided.

  The second fuel gas cutoff valve 32 and the fourth fuel gas cutoff valve 44 or the fuel gas cutoff valve 7, the third fuel gas cutoff valve 43, and the fourth fuel gas cutoff valve 44 as constituent members in the present embodiment are FIG. 4 is an example of a specific implementation of a configuration in which “a plurality of fuel gas cutoff valves are provided in series with respect to a fuel gas flow path” in the present invention.

First, a specific operation regarding fuel gas generation of the fuel cell system in the present embodiment will be described.

In the fuel cell system shown in FIG. 4, the raw material gas cutoff valve 3, the second fuel gas cutoff valve 32, and the fourth fuel gas cutoff valve 44 are opened, and the fuel gas cutoff valve 7 and the third fuel gas cutoff valve 43 are closed. Thus, the city gas or propane supplied from the raw material supply source is removed by a desulfurizer not shown in the figure, and then supplied as a raw material gas to the hydrogen generator 1 through the raw material gas channel 2. . The raw material gas supplied to the hydrogen generator 1 flows through the inside of the hydrogen generator 1 and is discharged to the fuel gas flow path 7 in the state of the raw material gas. The discharged source gas is supplied to the burner 8 through the fuel gas channel 6 and the second fuel gas channel 31. At the same time, in the burner 8, the igniter 21 is operated as an ignition operation in the burner 8, and combustion air is supplied by the fan 33. By detecting the flame formed in the burner 8 by the ignition operation by the frame rod 22, stable combustion in the burner 8 is monitored. When the ignition operation is completed, the igniter 21 stops. When the temperature detected by the temperature sensor 11 by combustion of the raw material gas in the burner 8 is raised to a temperature at which reforming reaction is possible (for example, 350 ° C.), by opening the steam shut-off valve 5, a steam supply source To the hydrogen generator 1 through the water vapor channel 4. The hydrogen generator 1 mixes the supplied raw material gas and steam, and then steam reforms using a catalyst to generate a hydrogen-rich fuel gas. The generated hydrogen-rich fuel gas can supply sufficient fuel gas to the fuel cell 41 by supplying the fuel gas to the burner 8 through the fuel gas passage 6 and the second fuel gas passage 31 and burning it. Raise the temperature to a temperature that can be achieved. When it is detected that the temperature detected by the temperature sensor 11 has increased to a temperature at which sufficient fuel gas can be supplied to the fuel cell 41, the fuel gas cutoff valve 7 and the third fuel gas cutoff valve 43 are opened, The fuel gas is supplied to the fuel cell 41 by closing the second fuel gas cutoff valve 32. The fuel cell 41 performs electrochemical power generation using air and fuel gas supplied from a power generation air supply source (not shown). The fuel gas that has not been used for power generation is discharged from the fuel cell 41 to the third fuel gas flow channel 42, supplied to the burner 8 through the third fuel gas flow channel 42 and the second fuel gas flow channel 31, and burned. The temperature of the generator 1 is maintained using the temperature detection value from the temperature sensor 11. When the temperature of the hydrogen generator 1 decreases due to consumption of the fuel gas in the fuel cell 41, the fuel cell 41 is discharged from the fuel cell 41 to the third fuel gas channel 42 by increasing the amount of raw material gas and water vapor to be supplied. The amount of fuel gas is increased, and the temperature of the hydrogen generator 1 is maintained using the temperature detection value from the temperature sensor 11. Alternatively, the combustion gas shut-off valve 10 is opened, and the combustion gas from the combustion gas supply source is also supplied to the burner 8 through the combustion gas flow path 9 for combustion, and the temperature detection value is detected from the temperature sensor 11 to maintain the temperature of the hydrogen generator 1. To implement.

Next, specific operations will be described with respect to gas leak detection of the fuel cell system in the present embodiment.

In the fuel cell system shown in FIG. 4, the control unit 14 shuts off the raw material gas shut-off valve 3, the water vapor shut-off valve 5, and the combustion gas shut-off valve 10 when the hydrogen generator 1 is stopped in the hydrogen generator 1. While shutting off the supply of water vapor and combustion gas, the fuel gas shut-off valve 7, the second fuel gas shut-off valve 32, the third fuel gas shut-off valve 43 and the fourth fuel gas shut-off valve 44 are shut off, and the hydrogen generator 1 and fuel By sealing the battery 41, the inflow of air from the downstream of the second fuel gas passage 31 or the like is prevented. The controller 14 diverts the temperature detection value from the temperature sensor 11 that detects the temperature rise and temperature maintenance of the hydrogen generator 1 during the hydrogen generation operation, so that the temperature of the hydrogen generator 1 is changed to the catalyst by the raw material gas. When the temperature falls below a predetermined temperature (for example, 500 ° C.) at which carbon deposition does not occur, a gas leak detection operation due to internal leaks from the plurality of fuel gas shutoff valves is started.

When performing gas leak detection operation due to internal leakage from the fourth fuel gas cutoff valve 44, the raw material gas cutoff is performed with the fuel gas cutoff valve 7, the third fuel gas cutoff valve 43, and the fourth fuel gas cutoff valve 44 shut off. The valve 3 and the second fuel gas shut-off valve 32 are opened, the raw material gas flow path 2, the hydrogen generator 1, and the raw material gas flow path 2 upstream of the fourth fuel gas shut-off valve 44, the hydrogen generator 1, the fuel gas flow The pressure in the section including the path 6, the second fuel gas channel 31, and the third fuel gas channel 42 is set to a pressure equivalent to that of the source gas supply source. On the other hand, the control unit 14 discharges the igniter 21 provided in the burner 8 with a high pressure to perform an ignition operation. When detected, it is determined that “there is a gas leak”, and a gas leak due to an internal leak from the fourth fuel gas cutoff valve 44 is detected. Further, when detecting the gas leak, the control unit 14 closes the raw material gas shut-off valve 3 and the second fuel gas shut-off valve 32, operates the fan 33, and sufficiently dilutes the leaked gas to a concentration that does not ignite. Discharge outside the fuel cell system . When the detection signal detects a value that can be determined as “no flame”, it is determined as “no gas leak”, the source gas cutoff valve 3 and the second fuel gas cutoff valve 32 are closed, and the fourth fuel gas cutoff valve is closed. The gas leak detection operation due to internal leak from 44 is terminated.

Further, when a gas leak detection operation due to internal leak from the second fuel gas cutoff valve 32 is performed, the raw material is kept in a state where the fuel gas cutoff valve 7, the third fuel gas cutoff valve 43, and the second fuel gas cutoff valve 32 are shut off. The gas cutoff valve 3 and the fourth fuel gas cutoff valve 44 are opened, the raw material gas passage 2, the hydrogen generator 1, and the raw material gas passage 2, the hydrogen generator 1, and the fuel upstream of the second fuel gas cutoff valve 32. The pressure in the section including the gas flow path 6 and the second fuel gas flow path 31 is set to a pressure equivalent to that of the source gas supply source. On the other hand, the control unit 14 discharges the igniter 21 provided in the burner 8 with a high pressure to perform an ignition operation. When detected, it is determined that “there is a gas leak”, and a gas leak due to an internal leak from the second fuel gas cutoff valve 32 is detected. Further, when detecting a gas leak, the control unit 14 closes the raw material gas cutoff valve 3 and the fourth fuel gas cutoff valve 44, operates the fan 33, and sufficiently dilutes the leaked gas to a concentration that does not ignite, from the burner 8. Discharge outside the fuel cell system . When the detection signal detects a value that can be determined as “no flame”, it is determined as “no gas leak”, the source gas cutoff valve 3 and the fourth fuel gas cutoff valve 44 are closed, and the second fuel gas cutoff valve is closed. The gas leak detection operation due to internal leak from 44 is terminated.

Furthermore, when performing a gas leak detection operation due to internal leakage from the third fuel gas cutoff valve 43, the raw material gas cutoff valve 3, with the third fuel gas cutoff valve 43 and the second fuel gas cutoff valve 32 shut off, The fuel gas shut-off valve 7 and the fourth fuel gas shut-off valve 44 are opened, the raw material gas flow path 2, the hydrogen generator 1, the raw material gas flow path 2 upstream of the third fuel gas shut-off valve 43, the hydrogen generator 1, The pressure in the section including the fuel cell 41, the fuel gas channel 6 and the second fuel gas channel 31 is set to a pressure equivalent to that of the source gas supply source. On the other hand, the control unit 14 discharges the igniter 21 provided in the burner 8 with a high pressure to perform an ignition operation. When detected, it is determined that “there is a gas leak”, and a gas leak due to an internal leak from the third fuel gas cutoff valve 43 is detected. Further, when the control unit 14 detects a gas leak, the control unit 14 closes the raw material gas cutoff valve 3, the fuel gas cutoff valve 7, and the fourth fuel gas cutoff valve 44, operates the fan 33, and sufficiently sets the leakage gas to a concentration that does not ignite. It is diluted and discharged from the burner 8 to the outside of the fuel cell system . When the detection signal detects a value that can be determined as “no flame”, it is determined as “no gas leak”, and the raw material gas cutoff valve 3, the fuel gas cutoff valve 7, and the fourth fuel gas cutoff valve 44 are closed, The gas leak detection operation due to the internal leak from the third fuel gas cutoff valve 43 is terminated.

Furthermore, when the gas leak detection operation due to internal leak from the fuel gas cutoff valve 7 is performed, the raw material gas cutoff valve 3 and the third fuel gas with the fuel gas cutoff valve 7 and the second fuel gas cutoff valve 32 shut off. The shutoff valve 43 and the fourth fuel gas shutoff valve 44 are opened, the raw material gas passage 2, the hydrogen generator 1, and the raw material gas passage 2, the hydrogen generator 1, and the fuel gas passage upstream of the fuel gas shutoff valve 7. 6 and the pressure in the section including the second fuel gas flow path 31 are set to the same pressure as the source gas supply source. On the other hand, the control unit 14 discharges the igniter 21 provided in the burner 8 with a high pressure to perform an ignition operation. When it is detected, it is determined that “there is a gas leak”, and a gas leak due to an internal leak from the fuel gas cutoff valve 7 is detected. Further, when the control unit 14 detects a gas leak, the control unit 14 closes the source gas cutoff valve 3, the third fuel gas cutoff valve 43, and the fourth fuel gas cutoff valve 44, operates the fan 33, and reaches a concentration that does not ignite the leaked gas. It is sufficiently diluted and discharged from the burner 8 to the outside of the fuel cell system . When the detection signal detects a value that can be determined as “no flame”, it is determined as “no gas leak”, and the source gas cutoff valve 3, the third fuel gas cutoff valve 43, and the fourth fuel gas cutoff valve 44 are closed. Then, the gas leak detection operation due to the internal leak from the fuel gas cutoff valve 7 is finished.

  When performing a gas leak detection operation due to an internal leak from the fuel gas cutoff valve 7 and the third fuel gas cutoff valve 43, first, a gas leak detection operation due to an internal leak from the second fuel gas cutoff valve 32 is performed, If it is performed after judging “no gas leak” from the second fuel gas cutoff valve 32, the gas leak detection operation due to internal leak from the fuel gas cutoff valve 7 or the third fuel gas cutoff valve 43 can be accurately performed. it can.

When the configuration of the fuel cell system in the present embodiment is adopted, the raw material gas shut-off valve 3 is opened even during a period in which the internal pressure drop occurs due to the temperature drop of the hydrogen generator 1 after the hydrogen generation operation is stopped. In a state where the sealed section including the hydrogen generator 1 is set to a pressure (positive pressure) equivalent to that of the source gas supply source, the control unit 14 performs an ignition operation by a high-pressure discharge to the igniter 21 and a flame by a detection signal from the frame rod 22. By monitoring the presence or absence, the second fuel gas cutoff valve 32 and the fourth fuel gas cutoff valve 44 or the fuel gas passage 6, the third fuel gas passage 42 and the second fuel gas with respect to the second fuel gas passage 31 are monitored. A configuration in which a plurality of fuel gas shut-off valves are provided in series with respect to the fuel gas flow path, such as the fuel gas shut-off valve 7, the third fuel gas shut-off valve 43, and the fourth fuel gas shut-off valve 44 for the flow path 31. To, by blocking any only one of the fuel gas shutoff valve, it is possible to detect a gas leakage due to internal leakage from the cut-off fuel shutoff valve. Further, since the igniter 21 and the frame rod 22 also serve as an igniter in the burner 8 and a flame detector in the burner 8 during the fuel gas generation operation, in addition to the effects described above, further cost reduction is achieved. Can be planned.

Further, in the configuration of the fuel cell system according to the present embodiment, the control unit 14 is configured to supply the blower air from the fan 33 that supplies air for diluting the leaked gas to the burner 8 when the gas leaks. in case it is detected, the blown air by operating the fan 33 is supplied to the burner 8, since the leakage gas may be diluted with air, the fuel from the burner 8 is sufficiently diluted to a concentration that does not ignite the leakage gas It can be discharged outside the battery system . Further, since the fan 33 also serves as combustion air supply means for supplying combustion air in the burner 8 during the fuel gas generation operation, it is possible to further reduce the cost in addition to the above-described effects.

In the gas leak detection in the present embodiment, the control unit has performed a series of operations for gas leak detection based on the temperature detection value from the temperature sensor 11, but this is not the only case, and from a stop obtained experimentally in advance. A series of operations may be performed according to the passage of a predetermined time based on the relationship between the passage of time and the temperature drop. In addition, the gas leak detection operation described above may be performed a plurality of times during the period from when the fuel cell system stops generating hydrogen until the temperature drops to a room temperature of about 30 ° C.

  In this embodiment, the igniter 21 that performs an ignition operation by high-pressure discharge is used as an example of a specific implementation of the igniter. However, the present invention is not limited to this. Also good. In addition, as a specific example of the implementation of the flame detector, the flame rod 22 that detects the flame by the ionic current is used. However, the present invention is not limited to this, and a flame temperature sensor that detects a temperature rise due to the flame may be used.

The fuel cell system according to the present invention, even when the internal pressure of the hydrogen generator is lowered, the raw material gas shutoff valve and the fuel gas shutoff valve and the second fuel gas shutoff valve and the valve of the third fuel gas shutoff valve closing and control of the presence or absence of gas leakage due to internal leakage from the fuel gas shutoff valve provided on the downstream channel from the hydrogen generator and the second fuel gas shutoff valve and the third fuel gas shut-off valve by the gas leakage detection means it is possible to detect, can be applied to the use of a fuel cell system or the like using a hydrogen generator that performs starting and stopping.

DESCRIPTION OF SYMBOLS 1,101 Hydrogen generator 2,104 Raw material gas flow path 3 Raw material gas cutoff valve 4 Water vapor flow path 5 Water vapor cutoff valve 6, 105 Fuel gas flow path 7 Fuel gas cutoff valve 8, 102 Burner 9 Combustion gas flow path 10 Combustion gas Shut-off valve 11 Temperature sensor 12 Gas leak detector 13 Blower 14 Control unit 21 Igniter 22 Frame rod 31 Second fuel gas flow path 32 Second fuel gas shut-off valve 33 Fan 41, 103 Fuel cell 42 Third fuel gas flow path 43 First 3 Fuel gas shut-off valve 44 Fourth fuel gas shut-off valve 106 Fuel gas bypass passage 107 Fuel off-gas passage 108, 109, 110, 111 Shut-off valve 112 Pressure sensor

Claims (4)

A hydrogen generator that generates a hydrogen-rich fuel gas using a source gas;
A burner for heating the hydrogen generator;
A source gas flow path for supplying the source gas from a source supply source to the hydrogen generator;
A source gas shutoff valve provided in the source gas flow path;
A fuel gas flow path for discharging the fuel gas from the hydrogen generator;
A fuel gas shut-off valve that is provided in the fuel gas flow path and passes or blocks the fuel gas discharged from the hydrogen generator;
A second fuel gas channel that branches from the fuel gas channel upstream of the fuel gas shut-off valve and supplies fuel gas to the burner;
A second fuel gas shut-off valve provided in the second fuel gas flow path for passing or shutting off the fuel gas discharged from the hydrogen generator;
A fuel cell connected to the fuel gas flow path downstream from the fuel gas shut-off valve and generating power using hydrogen and oxygen;
A third fuel gas flow path for discharging residual fuel gas discharged from the fuel cell without being used for power generation in the fuel cell to the second fuel gas flow path downstream from the second fuel gas shutoff valve; A third fuel gas shut-off valve that is provided in the third fuel gas flow path and passes or blocks the residual fuel gas discharged from the fuel cell;
A gas leak detecting means provided in the second fuel gas flow channel downstream from the junction with the third fuel gas flow channel to detect a gas leak;
Controlling the opening and closing of the source gas cutoff valve, the fuel gas cutoff valve, the second fuel gas cutoff valve, and the third fuel gas cutoff valve, and the gas leak detection means controls the fuel gas cutoff valve and the A second fuel gas shut-off valve and a control unit that performs a gas leak detection operation due to an internal leak from the third fuel gas shut-off valve ,
When the control unit performs a gas leak detection operation due to an internal leak from the second fuel gas shut-off valve , the source gas shut-off valve, the fuel gas shut-off valve, and the second gas shut-off valve when the hydrogen generator is stopped . after blocking the third fuel gas shutoff valve and the fuel gas shutoff valve, the fuel gas shutoff valve, it opens the raw material gas shutoff valve while blocking the second fuel gas shutoff valve and the third fuel gas shutoff valve Then , the fuel cell system is characterized in that the gas leak detection means determines whether or not there is a gas leak due to an internal leak from the second fuel gas shutoff valve . The control unit performs a gas leak detection operation due to an internal leak from the second fuel gas shut-off valve and determines that there is no gas leak due to an internal leak from the second fuel gas shut-off valve, and then the fuel gas shut-off valve In addition, the material gas shutoff valve and the third fuel gas shutoff valve are opened while the second fuel gas shutoff valve is shut off, and the gas leak detection means prevents gas leak due to internal leak from the fuel gas shutoff valve. The fuel cell system according to claim 1, wherein presence or absence is determined. The control unit performs a gas leak detection operation due to an internal leak from the second fuel gas cutoff valve and determines that there is no gas leak due to an internal leak from the second fuel gas cutoff valve, and then the second fuel gas The gas due to internal leak from the third fuel gas shut-off valve is opened by the gas leak detection means by opening the source gas shut-off valve and the fuel gas shut-off valve in a state where the shut-off valve and the third fuel gas shut-off valve are shut off. The fuel cell system according to claim 1, wherein presence or absence of leakage is determined. The gas leak detection means, using the igniter performs an ignition operation of the burner, and a flame detector for detecting a flame of the burner,
4. The fuel cell system according to claim 1 , wherein the control unit causes the igniter to perform an ignition operation, and performs presence / absence of flame detection by the flame detector. 5. .

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