JP5511419B2 - Hydrogen generator and fuel cell system - Google Patents

Description

  The present invention relates to a hydrogen generator that generates hydrogen-rich fuel gas from a raw material gas and steam by a steam reforming reaction, and a fuel cell system including the hydrogen generator.

  The fuel cell system includes a hydrogen generation device that generates steam-reformed raw gas such as city gas and LP gas to generate a hydrogen-rich fuel gas, a hydrogen-rich fuel gas and an oxidant gas that are generated by the hydrogen generation device. And a fuel cell that generates electric power using. Such a hydrogen generator includes a reformer that generates a reformed gas from a raw material gas and steam by a steam reforming reaction, a transformer that converts the generated reformed gas, and a reformed reformed gas. And a CO remover for reducing the carbon monoxide concentration.

  In such a hydrogen generator, the raw material gas is first supplied to the reformer. Then, it is heated by the combustion heat of the combustor that combusts the raw material gas or the hydrogen-rich fuel gas generated by the hydrogen generator. Further, water necessary for the steam reforming reaction is supplied to the reformer. The supplied water becomes steam by the combustion heat of the combustor and undergoes a steam reforming reaction with the raw material gas. Thereby, hydrogen-rich fuel gas is generated. Here, the temperature of the reformer is controlled so that about 85 to 90% of the supplied raw material gas can be steam reformed, for example, about 700 ° C. The temperature control of the reformer is performed by controlling the combustion amount of the combustor. The produced hydrogen-rich fuel gas contains about 10% of carbon monoxide gas. When this carbon monoxide gas is supplied to the fuel cell, the platinum catalyst of the fuel cell deteriorates and the voltage decreases, so it is necessary to reduce the carbon monoxide gas. Accordingly, the hydrogen-rich fuel gas is supplied to the transformer, and the carbon monoxide gas and water vapor contained therein are transformed into hydrogen gas and carbon dioxide gas by a shift reaction of both. The steam supplied to the reformer is also used for the steam necessary for this reaction. By this shift reaction, the concentration of carbon monoxide gas in the fuel gas after the modification is reduced to about 5000 ppm.

  This transformed fuel gas is supplied to a CO remover, where the residual carbon monoxide is converted to carbon dioxide gas by an oxidation reaction. As a result, the carbon monoxide concentration of the hydrogen-rich fuel gas delivered from the CO remover is reduced to about 10 ppm or less.

  The hydrogen-rich fuel gas thus generated by the hydrogen generator is supplied to the fuel cell, where it undergoes an electrochemical reaction with the oxidant gas to generate electricity and heat.

  In such a hydrogen generator, the key to the reaction for generating hydrogen-rich fuel gas is the catalyst used in each of the reformer, the shifter, and the CO remover. It greatly affects the performance and reliability of the generator and the fuel cell system. The reforming catalyst and the shift catalyst are oxidized when oxygen is present in the atmosphere, and the catalyst deteriorates. Further, when exposed to high temperature water vapor, it deteriorates due to oxidation by water vapor. When the catalyst deteriorates, the amount of hydrogen produced by the steam reforming reaction in the reformer decreases, and the amount of carbon monoxide reduced by the shift reaction in the shifter also decreases. As a result, the amount of hydrogen necessary for the electrochemical reaction in the fuel cell cannot be secured, and in addition to the inability to generate power in the fuel cell, the platinum catalyst of the fuel cell is poisoned by carbon monoxide. It is assumed that the performance and life of the fuel cell are significantly impaired. For this reason, it is very important for the whole fuel cell system to prevent oxidation of the reforming catalyst and the shift catalyst.

Therefore, in order to prevent oxidation of the reforming catalyst and the shift catalyst, when the hydrogen generator is shut down, first, the supply of the raw material gas and water to the reformer is stopped, and then the inside of the reformer becomes below a predetermined temperature. There has been known a hydrogen generation apparatus in which the inside of the hydrogen generation apparatus is maintained in a reducing atmosphere by supplying a raw material gas at that time. (For example, see Patent Document 1)
FIG. 5 is a block diagram showing a configuration of a conventional hydrogen generator described in Patent Document 1.

  As shown in FIG. 5, the conventional hydrogen generator includes a reformer 28 that generates a reformed gas from a raw material gas and steam by a steam reforming reaction, a combustor 29 that heats the reformer 28, and steam. And carbon monoxide gas to shift reaction of hydrogen gas and carbon dioxide gas, a CO remover 31 for reducing the carbon monoxide concentration by carbon monoxide selective oxidation, and a raw material gas to the reformer 28 A raw material valve 32 that cuts off the supply, a fuel gas valve 33 provided at the outlet of the CO remover 31, a reforming temperature detector 34 that detects the temperature inside the reformer 28, and the inside of the transformer 30 And a pressure detector 36 provided at the inlet of the raw material gas reformer 28 so that the pressure in the hydrogen generator can be detected.

  In the hydrogen generator described in Patent Document 1, when the operation is stopped, the supply of the raw material gas is stopped by closing the raw material valve 32, the supply of water is stopped, and the fuel gas valve 33 is also closed. As a result, the reformer 28 and the transformer 30 are filled with hydrogen-rich fuel gas that is a reducing gas. Thereafter, when the reforming temperature detector 34 or the shift temperature detector 35 is below a predetermined temperature, the raw material valve 32 and the fuel gas valve 33 are opened, and the gas inside the reformer 28 and the shifter 30 is used as the raw material. Purge with gas. Since the source gas is a hydrocarbon, the inside of the hydrogen generator 30 is maintained in a reducing atmosphere. Here, the predetermined temperature is a temperature at which carbon contained in the source gas does not decompose and precipitate.

  And if the temperature of the reformer 28 and the transformer 30 further falls, these internal pressures will fall, and it will be in a negative pressure state in the state as it is. Therefore, when the detected pressure of the pressure detector 36 becomes a predetermined pressure or less, the raw material valve 32 is opened and the raw material gas is supplied to the reformer 28 and the transformer 30 so that the inside thereof is maintained at a positive pressure. To do.

  As described above, in the conventional hydrogen generator, the inside of the reformer 28 and the shifter 30 is maintained in a reducing atmosphere to suppress the deterioration of the reforming catalyst and the shift catalyst.

JP 2004-307236 A

  However, the conventional hydrogen generator is configured to stop the supply of water together with the raw material gas and also close the fuel gas valve 33 provided at the outlet of the CO remover 31 as described above when the operation is stopped. However, even if the supply of water is stopped, the evaporation reaction does not stop immediately, and the evaporation reaction is continued until the water remaining in the reformer 28 is completely evaporated by the residual heat of the reformer 28. Will continue. As a result, the pressure inside the hydrogen generator rises due to the generation of water vapor, so that it is necessary to design the hydrogen generator withstand pressure, for example, to increase the pressure resistance of the housing material and increase the wall thickness. Disadvantageous.

  Further, although the gas in the reformer 28 contracts due to the temperature drop after the stop, if the fuel gas valve 33 is also closed when the operation is stopped as described above, purging, pressure holding or restarting is performed. When the raw material valve 32 is opened, depending on the temperature of the reformer 28, the internal pressure of the reformer 28 is higher than the pressure on the raw material path side, and steam flows back from the inside of the reformer to the raw material supply side. There is a possibility that the raw material is not properly supplied due to the blockage of the flow path.

  The present invention has been made to solve such a problem, and provides a hydrogen generator capable of suppressing the above-described adverse effects caused by an increase in internal pressure when operation is stopped, and a fuel cell system using the hydrogen generator. It is an object.

  In order to solve the above problems, a hydrogen generator of the present invention includes a hydrogen generator main body that generates a fuel gas containing hydrogen by a steam reforming reaction between a raw material gas and steam, and the raw material gas is converted into the hydrogen generator main body. A raw material supply device to be supplied to, a water supply device for supplying water for the steam reforming reaction to the hydrogen generator main body, and an outlet for the fuel gas of the hydrogen generator main body through a fuel gas path, A combustor for supplying heat necessary for the steam reforming reaction to the hydrogen generator main body by burning the gas delivered from the fuel gas outlet; and an air supply for supplying combustion air to the combustor. A controller for controlling operations of the raw material supplier, the water supplier, and the air supplier, and the combustor is in a state of burning the gas flowing in through the fuel gas path. When the stop process is started, the controller stops the supply of the raw material gas by the raw material supply device and the water supply by the water supply device, and then the combustion is continued in the combustor. The supply of the combustion air by the air supply unit is continued.

  According to this configuration, even after the supply of the raw material gas and water to the reformer is stopped, the fuel gas outlet of the hydrogen generator main body communicates with the combustor through the fuel gas path. The pressure is prevented from rising due to evaporation of the remaining water. Further, at that time, the operation amount of the air supply device is controlled so that the combustion of the combustor is continued in a state in which the fuel gas outlet of the hydrogen generating device main body communicates with the combustor through the fuel gas path. It can suppress that the combustible gas extruded with the water vapor | steam produced | generated within the main body is discharged | emitted in an unburned state.

  The hydrogen generation device includes a fuel gas valve provided in the fuel gas path, and the controller is configured such that an outlet of the fuel gas of the hydrogen generation device main body is the fuel gas during a period in which the combustion continues. The fuel gas valve may be configured to open so as to communicate with the combustor through a path.

  The hydrogen generator includes an igniter provided in the combustor, and after the supply of the raw material gas by the raw material supply device and the supply of water by the water supply device are stopped, the ignition device is ignited. It may be configured as follows. Here, “igniting the igniter after stopping the supply of source gas and water” means igniting the igniter for a predetermined time at least within the combustion continuation period after stopping the supply of source gas and water. Means. Therefore, the igniter need not be ignited continuously over the entire combustion continuation period after the supply of the raw material gas and water is stopped. In addition, this does not mean that the start timing of the ignition operation of the igniter is after the supply of the raw material gas and water is stopped, and the start of the ignition operation is performed in advance before the supply of the raw material gas and water is stopped. You may start.

  The hydrogen generation device includes a misfire detector that detects misfire in the combustor, and the controller is configured to stop the ignition operation of the igniter when the misfire is detected by the misfire detector. Also good.

  The controller may be configured to stop the ignition operation when a predetermined time has elapsed since the start of the ignition operation of the igniter.

  The hydrogen generation device may include a misfire detector that detects misfire in the combustor, and the controller may be configured to close the fuel gas valve when the misfire is detected by the misfire detector. According to this configuration, since the inside of the hydrogen generator main body is shut off from the outside air, when the temperature of the hydrogen generator drops thereafter, the intrusion of the outside air into the gas path in the hydrogen generator is shut off and reforming is performed. Deterioration due to oxidation of the catalyst or the like can be suppressed.

  The controller may be configured to continue supplying the combustion air by the air supplier after closing the fuel gas valve. According to this configuration, the combustion state is unstable immediately before the combustor misfires, so that incomplete combustion combustion exhaust gas may be discharged to the atmosphere, but after closing the fuel gas valve Since air is continuously supplied from the air supply device, unburned combustible gas and carbon monoxide contained in incompletely combusted exhaust gas are diluted and discharged, and safety can be ensured.

  The controller may be configured to increase an operation amount of the air supply unit after closing the fuel gas valve. According to this configuration, incompletely combusted exhaust gas is further diluted and discharged, so that safety can be further ensured.

  A fuel cell system according to the present invention includes the hydrogen generation device and a fuel cell that generates electric power using the fuel gas supplied from the hydrogen generation device.

  The fuel cell system further includes a temperature detector that detects a temperature inside the hydrogen generator main body, and the fuel cell system includes a stop process including the stop process of the hydrogen generator, wherein the controller When the temperature detector detects a temperature below a threshold value, the raw material supplier is configured to perform cathode purge for supplying the raw material gas to the cathode of the fuel cell, and the controller closes the fuel gas valve. After that, the combustion air supply by the air supply device may be continued at least until the cathode purge is started.

  According to this configuration, since the air supply device continues to operate until the cathode purge is performed, the temperature inside the hydrogen generator main body can be quickly reduced via the combustor. Thereby, the time until the cathode purge is performed can be shortened. As a result, deterioration of the fuel cell can be suppressed, and the stop processing time of the fuel cell system can be shortened.

  The present invention is configured as described above, and in the hydrogen generator and the fuel cell system using the same, it is possible to reduce the possibility of adverse effects caused by an increase in internal pressure when the hydrogen generator is shut down. Play.

It is a block diagram which shows the structure of the hydrogen generator which concerns on Embodiment 1 of this invention. It is a flowchart which shows the content of the stop process of the hydrogen generator of FIG. It is a block diagram which shows the structure of the fuel cell system which concerns on Embodiment 2 of this invention. It is a flowchart which shows the content of the stop process of the fuel cell system of FIG. It is a block diagram which shows the structure of the conventional hydrogen generator.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. In addition, the same referential mark is attached | subjected to the element which is the same or it corresponds through all the figures, and the overlapping description is abbreviate | omitted.

(Embodiment 1)
[Constitution]
FIG. 1 is a block diagram showing the configuration of the hydrogen generator according to Embodiment 1 of the present invention.

  As shown in FIG. 1, the hydrogen generator 101 of this embodiment includes a hydrogen generator main body 1, a raw material supplier 2, a water supplier 3, a combustor 4, a fuel gas path 5, and a fuel gas. A valve 6, a combustion air supplier 7, a misfire detector 8, and a controller 9 are provided as main components.

  The raw material supplier 2 is disposed on the raw material path 13 and supplies the raw material gas to the reformer 10 of the hydrogen generator main body 1 described later through the raw material path 13. The raw material supplier 2 is constituted by, for example, a plunger pump. The source gas needs to be a gas that can be reformed into a hydrogen-rich gas by a steam reforming reaction. Generally, a hydrocarbon gas is used as the source gas. Examples of the hydrocarbon gas include natural gas and city gas.

  A raw material valve 52 is provided in the raw material path 13 on the downstream side of the raw material supplier 2. The raw material valve 52 is constituted by, for example, an on-off valve.

  The water supplier 3 supplies water to the reformer 10 of the hydrogen generator main body 1 through the water supply path 14. The water supply device 4 is configured by a pump that pumps water from a water source such as a water storage tank or city water.

  The hydrogen generator main body 1 includes a reformer 10, a transformer 11, and a CO remover 12. The hydrogen generator main body 1 is formed in a container shape, for example, and a reformer 10, a transformer 11 and a CO remover 12 are formed so as to partition the internal space of the container.

  The reformer 10 includes a reforming catalyst (not shown). As the reforming catalyst, for example, a reforming catalyst using Ru or Ni as a catalyst metal is used. The reformer 10 heats the water supplied from the water supply device 3 with the heat supplied from the fuel device 4 to generate water vapor. The steam and the raw material gas supplied from the raw material supplier 2 are subjected to a steam reforming reaction by the action of the reforming catalyst to generate a hydrogen-rich fuel gas (reformed gas). For this steam reforming reaction, heat supplied from the combustor 4 is used. The temperature of the reformer 10 is controlled so that about 85 to 90% of the supplied raw material gas can be steam reformed, for example, about 700 ° C. The reformer 10 is provided with a temperature detector 27 that detects the temperature of the reformer 10. The temperature detector 27 is composed of a temperature sensor such as a platinum resistance thermometer or a thermistor. The temperature of the reformer 10 detected by the temperature detector 27 is input to the controller 9.

  The transformer 11 includes a shift catalyst. For example, a Cu—Zn-based catalyst is used as the shift catalyst. The transformer 11 transforms the hydrogen-rich fuel gas generated by the reformer 10 by the action of the shift catalyst. Specifically, the carbon monoxide gas and water vapor contained in the hydrogen-rich fuel gas are transformed into hydrogen gas and carbon dioxide gas by the shift reaction of both. This shift reaction reduces the concentration of carbon monoxide gas in the hydrogen-rich fuel gas to about 5000 ppm.

  The CO remover 12 includes an oxidation catalyst. As the oxidation catalyst, for example, a catalyst containing Pt is used. The CO remover 12 mixes air supplied from an oxidizing air supply source (not shown) with the hydrogen-rich fuel gas transformed by the transformer 11, and in the hydrogen-rich fuel gas by the action of the oxidation catalyst. Carbon monoxide is reacted with oxygen in the air. Thereby, carbon monoxide in the hydrogen-rich fuel gas is changed to carbon dioxide gas. As a result, the carbon monoxide concentration of the hydrogen-rich fuel gas delivered from the CO remover 12 is reduced to about 10 ppm or less.

  The fuel gas path 5 is a device (here, a fuel cell) that consumes the fuel gas rich in hydrogen (hereinafter, simply referred to as “fuel gas”) delivered from the CO remover 12 of the hydrogen generator main body 1. ) Through the combustor 4. In general, the fuel gas path includes a fuel gas supply path that supplies fuel gas from the hydrogen generator main body 1 to the internal fuel gas path of the fuel cell, and the above-described internal fuel gas path ( 1, and a fuel gas discharge path that guides unconsumed (unreacted) fuel gas (anode offgas) discharged from the internal fuel gas path to the combustor 4. In some cases, a bypass path is provided for bypassing the fuel cell and starting the fuel gas from the hydrogen generator main body 1 to the combustor 4 when the hydrogen generator main body 1 is started (see FIG. 3). The bypass path also constitutes the fuel gas path 5.

  A fuel gas valve 6 is disposed in a portion of the fuel gas path 5 near the combustor 4. The fuel gas valve is composed of, for example, an on-off valve, and opens and closes to open (close) and shut off (close) the fuel gas path 5.

  The combustor 4 mixes the fuel gas as the combustion gas supplied from the fuel gas path 5 with the air supplied from the combustion air supply device 7 and burns it. The combustion exhaust gas by this combustion is discharged from the exhaust port to the outside of the hydrogen generator 101 through a combustion exhaust gas path (not shown). This combustion exhaust gas path is configured so that the combustion exhaust gas flowing through it exchanges heat with the reformer 10 of the hydrogen generator main body 1 (not shown). With this configuration, when the fuel gas is burned in the combustor 4, the reformer 10 is heated by the generated combustion exhaust gas. With this configuration, as will be described later, when combustion air is supplied to the combustor 4 after the misfire of the combustor 4, the combustion air exchanges heat with the reformer 10 to cool the reformer 10. The combustor 4 is composed of, for example, a flame burner. The combustor 4 includes an igniter 51, and the igniter 51 is operated by the ignition command from the controller 9 to ignite the combustor 4.

  The combustor 4 is provided with a misfire detector 8 that detects that the combustor 4 has misfired. A detection signal of the misfire detection 8 is input to the controller 9. The misfire detector 4 is composed of, for example, a frame rod.

  The combustion air supplier 7 supplies combustion air to the combustor 4. The combustion air supply device 7 is composed of, for example, a sirocco fan.

  In the present embodiment, the controller 9 controls the overall operation of the hydrogen generator 101. Specifically, the controller 9 receives a detection signal from a required detector (not shown) of the hydrogen generator 101 and input information (command, input data, etc.) from an input device (not shown). The controller 9 performs a required process based on these inputs. And based on the process, a control signal is output to a required component, this is controlled, and required information is output to an output device (not shown). In particular, the controller 9 performs a stop process by controlling the raw material supplier 2, the water supplier 3, the fuel gas valve 6, the combustion air supplier 7, and the igniter 51. In this stop process, the detection signal input from the misfire detector 8 and the temperature of the reformer 10 input from the temperature detector 27 are used.

  The controller 9 includes a calculation unit (not shown), a storage unit (not shown), and a timer 53, and the calculation unit reads and executes a predetermined program stored in the storage unit. The above control is performed. The controller 9 is composed of, for example, a microcomputer, the arithmetic unit is composed of its CPU, and the storage unit is composed of its internal memory. The timer 53 is a function realized by a program stored in the storage unit.

  Here, in the present invention, the controller means not only a single controller but also a group of controllers controlled by a plurality of controllers in cooperation. Therefore, the controller 9 is not necessarily configured by a single controller, and a plurality of controllers may be arranged in a distributed manner so that the hydrogen generator 101 is controlled in cooperation with each other. Good.

[Operation]
Next, the operation of the hydrogen generator 101 configured as described above will be described. This operation is performed under the control of the controller 9. The hydrogen generation apparatus 101 warms up the hydrogen generation apparatus 101 from a stopped state and shifts to a fuel gas generation operation for safely and smoothly generating a hydrogen-rich fuel gas with a low carbon monoxide concentration. And at least three operation modes: a fuel gas generation operation for generating fuel gas, and a stop process for safely and smoothly stopping the hydrogen generator 101 from the fuel gas generation operation.

  First, the startup process and the fuel gas generation operation will be described in a simplified manner. The hydrogen generator 101 is activated by the activation start control signal from the controller 9. Specifically, the controller 9 issues an open command to the fuel gas valve 6. As a result, the fuel gas valve 6 is opened and the fuel gas path 5 is conducted (opened). Thereafter, the controller 9 issues an operation command to the raw material supplier 2, the water supplier 3, and the combustion air supplier 7 and issues an ignition command to the igniter 51 of the combustor 4. Further, the material valve 52 is opened. As a result, the raw material supplier 2 supplies the raw material gas to the hydrogen generator main body 1 through the raw material path 13. The water supplier 3 supplies water to the hydrogen generator 1 via the water supply path 14. The combustor 4 is ignited. Thereby, the hydrogen generator main body 1 generates hydrogen-rich fuel gas by the steam reforming reaction. Then, this fuel gas is supplied to the device (here, the fuel cell) that consumes the fuel gas through the fuel gas path 5, and the fuel gas (anode off gas) that has not been consumed there is led to the combustor 4. In the combustor 4, the anode off gas is mixed with the combustion air supplied from the combustion air supplier 7 and burned. The combustion exhaust gas generated by this combustion exchanges heat with the reformer 10 to heat it. Thereby, the steam reforming reaction in the reformer 10 proceeds.

  Next, stop processing that characterizes the present invention will be described.

  FIG. 2 is a flowchart showing the contents of the stop process of the hydrogen generator of FIG. This stop process is performed by the calculation unit of the controller 9 reading and executing the stop process program stored in the storage unit of the controller 9.

  In FIG. 2, the hydrogen generator 101 starts the stop process in response to a stop process start control signal from the controller 9.

  First, the controller 9 controls the raw material supplier 2 to stop the supply of the raw material gas (step S1). At this time, the controller 9 closes the raw material valve 52 after stopping the supply of the raw material gas. Next, the controller 9 controls the water supplier 3 to stop the water supply (step S2). The supply gas supply stop and the water supply stop may be performed in the reverse order or simultaneously.

  Next, the controller 9 operates the igniter 51 (step S3).

  Next, the controller 9 monitors whether the misfire detector 8 detects misfire (NO in step S4).

  Here, even if the supply of water is stopped, the evaporation reaction does not stop immediately, and the evaporation reaction continues until the water remaining in the reformer 10 is completely evaporated. Thereby, the increase in the volume of the gas in the reformer 10 continues. On the other hand, unlike the conventional example, in the present embodiment, the fuel gas valve 6 remains open in the same manner as during operation from the stop of the supply of the raw material gas and water until the misfire detection by the misfire detector 8, and the fuel gas path Through 5, hydrogen-rich fuel gas containing water vapor is supplied to the combustor 4. Here, after the supply of the raw material gas and water is stopped, the gas generated in the reformer 10 does not necessarily have a predetermined composition as a fuel gas. Therefore, this is hereinafter referred to as “combustible gas”. Sometimes called. Further, the combustion air supply device 7 continues to supply combustion air to the combustor 4. Thereby, the combustor 4 continues combustion. By the way, after the supply of the raw material and water is stopped, the amount of combustible gas contained in the gas pushed out by water evaporation in the reformer 10 and supplied to the combustor 4 gradually decreases. 4 becomes easy to misfire. However, in the present embodiment, the igniter 51 continues the igniting operation during that period, so that even if the combustor 4 misfires, it ignites immediately. For this reason, the continuation of combustion of the combustible gas in the gas extruded from the reformer 10 is extended. Thus, step S4 is a combustion continuation step that characterizes the present invention. As a result, the pressure in the hydrogen generator main body 1 is prevented from rising due to evaporation of the remaining water. Moreover, the pressure resistance design of the hydrogen generator main body 1 is facilitated. For example, it is possible to use a low-cost material for the casing of the hydrogen generator main body 1 and to reduce the wall thickness of the casing. And compactness can be realized. Also, if hydrogen-rich fuel gas containing water vapor is discharged to the atmosphere as it is, if there is an ignition source near the exhaust port of the combustion exhaust gas, there is a risk of ignition or explosion, but in the present embodiment, they are burned Therefore, occurrence of the above problem can be suppressed.

  Eventually, when all the residual water in the reformer 10 has been evaporated, the volume of gas in the reformer 10 stops increasing, and the combustible gas (from the hydrogen generator main body 1 to the combustor 4) from the fuel gas path 5 stops. The supply of generated gas) stops. Thereby, the combustor 4 misfires. Then, the misfire detector 8 detects this misfire and outputs a misfire detection signal to the controller 9. The controller 9 receives this misfire detection signal and detects misfire of the combustor 4 (YES in step S4).

  When detecting the misfire, the controller 9 stops the ignition operation of the igniter 51 (step S5).

  Next, the controller 9 closes the fuel gas valve 6 (step S6). As a result, the gas path inside the hydrogen generator main body 1 is shut off from the outside air, and when the temperature of the hydrogen generator drops thereafter, the intrusion of outside air into the gas path inside the hydrogen generator is shut off, and The deterioration of the quality catalyst and the shift catalyst due to oxidation is prevented.

  Next, the controller 9 increases the operation amount (output of the air supply device) of the combustion air supply device 7 (step S7). In the present embodiment, control is performed so that the operation amount (output) of the combustion air supply device 7 is maximized. The operation amount after the increase of the combustion air supply device 7 does not necessarily need to be maximized, and may be at least larger than the operation amount when the fuel cell system 102 is performing the power generation operation with the maximum power. Due to the increase in the operation amount, the amount of combustion air supplied by the combustion air supplier 7 increases. Here, immediately before the combustor 4 is misfired, the combustion state is unstable, and therefore, incomplete combustion combustion exhaust gas may be discharged to the atmosphere. In this way, the fuel gas valve 6 is closed. By continuing the supply of the combustion air and increasing the supply amount of the combustion air, the incomplete combustion combustion exhaust gas can be diluted and discharged.

  Next, the controller 9 starts measuring the elapsed time after increasing the operation amount of the combustion air supplier 7 (step S8). The elapsed time is measured using a timer 53.

  Next, the controller 9 waits until the elapsed time after increasing the operation amount of the combustion air supplier 7 becomes equal to or greater than the first stop threshold (NO in step S9). Specifically, the controller 9 (more precisely, the storage unit) stores a first stop threshold value with respect to the elapsed time since the operation amount of the combustion air supply device 7 is increased. The elapsed time after increasing the operation amount of the combustion air supply unit 7 calculated based on the time input from the timer 53 is compared with the first stop threshold value, and the elapsed time is the first stop time. It is determined whether or not the threshold value is exceeded (step S9). If the elapsed time is less than the first stop threshold, the CPU waits for the elapsed time to be equal to or greater than the first stop threshold (NO in step S9).

  When the elapsed time is equal to or greater than the first stop threshold (YES in step S9), the combustion air supply unit 15 is stopped (step S10). The first stop threshold is defined as a time during which the gas remaining in the combustor 4 can be purged into the atmosphere after the fuel gas valve 6 is closed. That is, in step S9, whether the amount of combustion air supplied after the fuel gas valve 6 is closed is equal to or greater than the supply amount (threshold supply amount) that can purge the gas remaining in the combustor 4 into the atmosphere. The above-described step S9, which is intended to determine whether or not, is determined by the elapsed time, is an example.

  Thus, the stop process ends. By the end of this stop process, the hydrogen generator 101 is completely stopped.

  As described above, according to the hydrogen generator 101 of the present embodiment, it is possible to reduce the possibility of adverse effects due to an increase in the internal pressure of the hydrogen generator main body 1 when the operation of the hydrogen generator 101 is stopped. it can. In this embodiment, since the pressure increase in the hydrogen generator main body 1 can be suppressed, purging of gas including water vapor or fuel gas remaining in the hydrogen generator main body 1 after the fuel gas valve 6 is closed is performed. The raw material gas is supplied for holding pressure (complementary pressure) to the hydrogen generator main body 1 or restarting the hydrogen generator 101 when the internal pressure decreases due to a temperature drop in the hydrogen generator main body 1 after the valve 6 is closed. Even when configured in this way, when the raw material valve 52 downstream of the raw material supplier 2 is opened, the steam flows backward from the inside of the reformer 10 to the raw material path 13 side, and is disposed on the path for supplying the raw material gas. It can suppress that the made raw material supply device 2 is exposed to water vapor | steam, and a failure generate | occur | produces.

[Modifications related to ignition operation]
<Omission of ignition operation>
In the above, the ignition operation is performed after the supply of raw materials and water is stopped. This ignition operation is performed for the purpose of stably continuing the combustion of the combustible gas pushed out from the reformer 10 after the supply of raw materials and water is stopped. Therefore, it is preferable to perform the ignition operation, but this may be omitted when the stop process control is simplified.

<Start timing of ignition operation>
In the above, the ignition operation is started after the supply of the raw materials and water is stopped. However, in view of the above-described purpose, the ignition operation may be performed after the supply of the raw materials and water is stopped. Therefore, the ignition operation may be started simultaneously with or before the supply of raw materials and water is stopped.

<Ignition stop timing>
In other words, the ignition operation of the igniter 51 is performed in order to extend the combustion duration time of the combustible gas in the gas pushed out from the reformer 10. Therefore, it is preferable that the ignition operation of the igniter 51 is continued until the extrusion of the combustible gas from the reformer 10 stops. Therefore, in the above, the ignition operation of the igniter 51 is stopped after detecting misfire. However, in the sense that even if a small amount is obtained, the effect of extending the combustion duration of the combustor 4 is obtained, it is not necessary to continue the ignition operation until the misfire is detected, before the misfire of the combustor 4 is detected. The ignition operation may be stopped. That is, the extension effect can be obtained by operating the igniter 51 for a predetermined time within the combustion continuation period after the supply of the raw material and water is stopped. Moreover, it is preferable that the predetermined time is a time estimated that the combustion of the combustor 4 can be continued by the ignition operation. Such an estimated time can be obtained by experiment, simulation, calculation, or the like.

In the above description, whether or not the amount of combustion air supplied after closing the fuel gas valve 6 is equal to or greater than the supply amount (threshold supply amount) that allows the gas remaining in the combustor 4 to be purged into the atmosphere. Is determined based on the elapsed time since the amount of operation of the combustion air supplier 7 is increased, but may be determined using parameters other than this. As such a parameter, for example, an elapsed time from the closing of the fuel gas valve 6 can be cited.
(Embodiment 2)
FIG. 2 is a block diagram showing the configuration of the fuel cell system according to Embodiment 2 of the present invention. As shown in FIG. 2, the fuel cell system 102 of the present embodiment includes the hydrogen generator 101, the fuel cell 17, and the oxidant gas supplier 19 of the first embodiment as main components. .

  The fuel cell 1 generates electricity and heat by causing an electrochemical reaction between a fuel gas containing hydrogen and an oxidant gas containing oxygen. As the fuel cell 1, for example, a solid polymer electrolyte fuel cell, a phosphoric acid fuel cell, a solid oxide fuel cell, a molten carbonate fuel cell, or the like can be used.

  Inside the fuel cell 17, an internal fuel gas passage 43 for supplying fuel gas to the anode and discharging unconsumed fuel gas therefrom, and an oxidant gas to the cathode and discharging unconsumed oxidant gas therefrom. And an internal oxidant gas path 44 is formed. The upstream end of the internal fuel gas path 43 is connected to the fuel gas outlet of the CO remover 12 of the hydrogen generator main body 1 through the fuel gas supply path 16. The fuel gas supply path 16 is provided with a fuel gas inlet valve 21 that opens and closes the fuel gas supply path 16 by opening and closing the fuel gas supply path 16. The fuel gas inlet valve 21 is constituted by an on-off valve, for example. The downstream end of the fuel gas path 43 is connected to the combustor 4 through the fuel gas discharge path 41. The fuel gas discharge path 41 is provided with a fuel gas outlet valve 23 that opens and closes the fuel gas supply path 41 by opening and closing the fuel gas discharge path 41. The fuel gas outlet valve 23 is constituted by, for example, an on-off valve.

  A fuel cell bypass path 20 is provided so as to connect a portion upstream of the fuel gas inlet valve 21 in the fuel gas supply path 16 and a portion downstream of the fuel gas outlet valve 23 in the fuel gas discharge path 41. Yes. The fuel cell bypass path 20 is provided with a fuel cell bypass valve 22 that opens (closes) and shuts off (closes) the fuel cell bypass path 20 by opening and closing the fuel cell bypass path 20. The fuel cell bypass valve 22 is constituted by an on-off valve, for example.

  With this configuration, when the fuel gas inlet valve 21 and the fuel gas outlet valve 23 are opened and the fuel cell bypass valve 22 is closed, the fuel gas supplied from the hydrogen generator main body 1 is supplied to the fuel gas supply path 16 and the fuel cell 17. The internal fuel gas passage 43 and the fuel gas discharge passage 41 flow to the combustor 4. On the other hand, when the fuel gas inlet valve 21 and the fuel gas outlet valve 23 are closed and the fuel cell bypass valve 22 is opened, the fuel gas supplied from the hydrogen generator main body 1 is supplied to the fuel gas supply path 16 and the fuel cell bypass path 20. And the fuel gas discharge path 41 to the combustor 4.

  Therefore, the path of the fuel gas flowing to the combustor 4 through the fuel gas supply path 16, the internal fuel gas path 43 of the fuel cell 17 and the fuel gas discharge path 41, the fuel gas supply path 16 and the fuel cell bypass path. 20 and the fuel gas path that flows to the combustor 4 through the fuel gas discharge path 41 constitute the fuel gas path 5.

  On the other hand, the upstream end of the internal oxidant gas path 44 of the fuel cell 17 is connected to the oxidant gas supply unit 19 through the oxidant gas supply path 18. Here, the oxidant gas supply unit 19 supplies air as the oxidant gas to the internal oxidant gas passage 44. The oxidant gas supply device 19 is composed of, for example, a blower. The oxidant gas supply path 18 is provided with an oxidant gas valve 42 that opens (closes) and shuts off (closes) the oxidant gas supply path 18 by opening and closing thereof. The oxidant gas valve 42 is constituted by an on-off valve, for example.

  The downstream end of the internal oxidant gas path 44 is connected to the combustor 4 through the oxidant gas discharge path 24. The oxidant gas discharge path 24 is provided with a cathode purge gas outlet valve 26 that opens (closes) and shuts off (closes) the oxidant gas discharge path 24 by opening and closing the oxidant gas discharge path 24. The cathode purge gas outlet valve 26 is constituted by, for example, an on-off valve.

  A cathode purge gas passage 45 is provided so as to connect a portion of the raw material passage 13 downstream of the raw material supplier 2 and a portion of the oxidant gas supply passage 18 downstream of the oxidant gas valve 42. The cathode purge gas passage 45 is provided with a cathode purge gas inlet valve 25 that opens (closes) and shuts off (closes) the cathode purge gas passage 45 by opening and closing thereof. The cathode purge gas inlet valve 25 is constituted by, for example, an on-off valve.

  In this embodiment, the controller 9 includes an oxidant gas supply device 19, a fuel gas inlet valve 21, a fuel cell bypass valve 22, a fuel gas outlet valve 23, a cathode purge gas inlet valve 25, a cathode purge gas outlet valve 26, and an oxidizer. The operation of the agent gas valve 42 is controlled. In addition, another controller that controls these components 19, 21 to 23, 25, 26, and 42 is provided, and the controller and the controller 9 cooperate to control the fuel cell system. Also good.

  Next, the operation of the fuel cell system 102 configured as described above will be described. This operation is performed under the control of the controller 9. The fuel cell system 102 warms up the hydrogen generator main body 1 from a state where the fuel cell system 102 is stopped, and starts up the fuel cell system 102 so that the fuel cell system 102 can be safely and smoothly shifted to a power generation operation. It has at least three operation modes of operation and stop processing for safely and smoothly stopping the fuel cell system 102 from the power generation operation.

  First, the startup process and the power generation operation will be described in a simplified manner. The fuel cell system 102 is activated by the activation start control signal from the controller 9.

  In the fuel cell system 102, in the stop state (standby state), the fuel gas inlet valve 21, the fuel cell bypass valve 20, and the fuel gas outlet valve 23 are closed. In the internal fuel gas path 43), the raw material gas is sealed. Further, in the present embodiment, the fuel cell bypass valve 22 plays the role in place of the fuel gas valve 6 of the first embodiment, and the hydrogen generator main body 1 is described in the first embodiment. Thus, the source gas is sealed. Further, the cathode purge gas inlet valve 25, the cathode purge gas outlet valve 26, and the oxidant gas valve 42 are closed. As will be described later, the source gas is sealed in the cathode (more precisely, the internal oxidant gas path 44). Has been.

  In this state, when a start control signal is output from the controller 9, the fuel cell bypass valve 22 is opened, and then the hydrogen generator 101 is started. Since this starting operation has been described in detail in the first embodiment, the redundant description thereof is omitted here. However, the fuel gas generated in the hydrogen generator main body 1 is supplied to the combustor 4 through the fuel gas supply path 26, the fuel cell bypass path 20, and the fuel gas discharge path 41.

  A predetermined fuel gas supply threshold temperature (second predetermined temperature) of the reformer 10 is stored in the storage unit of the controller 9, and the controller 9 detects the reforming detected by the temperature detector 27. When the temperature of the vessel 10 reaches this fuel gas supply threshold temperature, the fuel gas inlet valve 21 and the fuel gas outlet valve 23 are opened and the fuel cell bypass valve 22 is closed. As a result, the fuel gas is supplied from the hydrogen generator main body 1 to the anode of the fuel cell 17. At this time, the raw material gas sealed in the anode (internal fuel gas path 43) is discharged to the combustor 4 through the fuel gas discharge path 41 and burned there.

  Further, the controller 9 opens the oxidant gas valve 42 and the cathode purge gas outlet valve 26 and supplies the oxidant gas (air) from the oxidant gas supply unit 19 to the cathode of the fuel cell 17. At this time, the raw material gas sealed in the cathode (internal oxidant gas path 44) is discharged to the combustor 4 through the oxidant gas discharge path 24 and burned there.

  In this way, the fuel cell system 102 shifts to the power generation operation, and in the power generation operation, the fuel cell 17 supplies the fuel gas supplied from the hydrogen generator main body 1 and the oxidation gas supplied from the oxidant gas supply device 19. Electrochemical reaction with the agent gas generates electricity and heat. The generated electricity is supplied to the load through an output terminal (not shown). The generated heat is recovered by an exhaust heat recovery system (not shown) and used for the user.

  The fuel gas (anode off gas: combustion gas) that has not been consumed in the fuel cell 17 is supplied to the combustor 4 and burned there. Further, the oxidant gas (cathode off gas) that has not been consumed in the fuel cell 17 is supplied to the combustor 4 where it is used for combustion of the combustion gas together with the combustion air supplied from the combustion air supply device 7.

  Next, the stop process will be described.

  FIG. 4 is a flowchart showing the contents of the stop process of the fuel cell system 102 of FIG. This stop process is performed by the calculation unit of the controller 9 reading and executing the stop process program stored in the storage unit of the controller 9.

  In FIG. 3, the fuel cell system 102 starts the stop process in response to a stop process start control signal from the controller 9.

  The controller 9 first stops the supply of the oxidant gas and performs a combustible gas combustion process in the hydrogen generator 101. Specifically, the controller 9 stops the supply of the oxidant gas by the oxidant gas supply unit 19 and closes the gas oxidant gas valve 42. The combustible gas combustion process is a modification of steps S1 to S6 of FIG. Since Steps S1 to S6 have been described in detail in the first embodiment, the overlapping description will be omitted here, and differences will be described. In the present embodiment, at the start of the stop process of the fuel cell system, the fuel gas flows from the hydrogen generating body 1 to the combustor 4 via the internal fuel gas path 43 of the fuel cell 17. In the combustible gas combustion process of the hydrogen generator 101, the controller 9 first stops the supply of the raw material gas and water (steps S1 and S2 in FIG. 2), opens the fuel cell bypass valve 22, and opens the fuel gas inlet. The valve 21 and the fuel gas outlet valve 23 are closed. As a result, the fuel gas is sealed in the anode of the fuel cell 17 (more precisely, the internal fuel gas path 43). On the other hand, the combustible gas sent out from the hydrogen generator main body 1 by water evaporation inside the hydrogen generator main body 1 continues to flow to the combustor 4 via the fuel cell bypass path 20, and this combustible gas is the same as in the first embodiment. To burn.

  Thereafter, when the misfire is detected by the misfire detector 8, the controller 9 closes the fuel cell bypass valve 22 instead of the fuel gas valve 6 (see step S6 in FIG. 2). Thereby, the source gas is sealed in the hydrogen generator main body 1.

  Thereafter, the controller 9 increases the operation amount of the combustion air supplier 7 and continues the supply of the combustion air (step S22). This is to promote the temperature drop of the reformer 10.

  Next, the controller 9 waits for the temperature of the reformer 10 detected by the temperature detector 27 to fall below a predetermined threshold temperature (NO in step S22). This predetermined temperature threshold is preferably determined as follows. The temperature of the reformer 10 decreases due to heat dissipation after the misfire of the combustor 4. On the other hand, in the cathode purge described later, the gas sent from the internal oxidant gas flow path 44 of the fuel cell 17 is combusted in the combustor 4, so that the temperature of the reformer 10 rises due to this combustion. Therefore, the predetermined threshold temperature is preferably set to a temperature that is equal to or lower than the heat resistance temperature of the reforming catalyst even when the temperature rise of the reformer 10 due to cathode purge is added. In other words, the predetermined threshold temperature is preferably set to be equal to or lower than a temperature obtained by subtracting the temperature rise of the reformer 10 due to cathode purge from the heat resistance temperature of the reforming catalyst.

  Then, when the temperature of the reformer 10 detected by the temperature detector 27 becomes equal to or lower than a predetermined threshold temperature, the controller 9 changes the operation amount of the combustion air supply device 7 at the time of the cathode purge process that is performed after the next step. The amount of air that is optimal for combustion in the combustor 8 is reduced to a level at which it can be supplied (step S24), and the purge of the cathode of the fuel cell 17 is started (step S25). Thereafter, the controller 9 starts measuring the duration of cathode purge (hereinafter referred to as purge time) (step S26). In this cathode purge, the controller 9 opens the cathode purge gas inlet valve 25 and the cathode purge gas outlet valve 26. Then, the raw material supplier 2 is operated. As a result, the source gas is supplied to the cathode (internal oxidant gas path 44) of the fuel cell 17 through the cathode purge gas path 45, and the oxidant gas present at the cathode is purged.

  Next, the controller 9 waits for the purge time to become equal to or longer than the second stop threshold (NO in step S27). The second stop threshold is preferably set to a time during which at least the oxidant gas in the internal oxidant gas passage 44 can be discharged from the internal oxidant gas passage 44.

  When the purge time becomes equal to or longer than the second stop threshold, the controller 9 stops the cathode purge (step S28). Specifically, the controller 9 stops the raw material supplier 2 and closes the cathode purge gas inlet valve 25 and the cathode purge gas outlet valve 26. As a result, the source gas is sealed in the cathode (more precisely, the internal oxidant gas path 44) of the fuel cell 17, and the cathode purge process is stopped.

  In the cathode purge process, the raw material gas is supplied to the oxidant gas path of the fuel cell 17. However, the controller 9 opens the raw material gas valve 52 and the fuel cell bypass valve 22 to supply hydrogen gas. It may be configured to improve the combustion stability of the combustor 4 by supplying the raw material gas also into the generator 101 and increasing the amount of combustible gas supplied to the combustor 4 during the cathode purge process. Absent.

  Next, after stopping the cathode purge process, the controller 9 increases the operation amount of the combustion air supplier 7 (output of the air supplier) (step S29). In the present embodiment, control is performed so that the operation amount (output) of the combustion air supply device 7 is maximized. The operation amount after the increase of the combustion air supply device 7 does not necessarily need to be maximized, and may be at least larger than the operation amount when the fuel cell system 102 is performing the power generation operation with the maximum power. Due to the increase in the operation amount, the amount of combustion air supplied by the combustion air supplier 7 increases. Here, immediately before the combustor 4 is misfired, the combustion state is unstable, so that incomplete combustion combustion exhaust gas may be discharged to the atmosphere. Even after the battery bypass valve 22 is closed, the supply of combustion air is continued and the supply amount of the combustion air is also increased, so that the combustion exhaust gas of incomplete combustion can be diluted and discharged.

  Next, the controller 9 starts measuring the elapsed time after increasing the operation amount of the combustion air supplier 7 (step S30). The elapsed time is measured using a timer 53.

  Next, the controller 9 waits for the elapsed time after increasing the operation amount of the combustion air supply device 7 to be equal to or greater than the third stop threshold (NO in step S31). Specifically, the controller 9 (more precisely, the storage unit) stores a third stop threshold value with respect to the elapsed time since the operation amount of the combustion air supply device 7 is increased. The elapsed time after increasing the operation amount of the combustion air supply unit 7 calculated based on the time input from the timer 53 is compared with the third stop threshold value, and the elapsed time is the third stop time. It is determined whether or not the threshold value is exceeded (step S31). If the elapsed time is less than the third stop threshold, the CPU waits for the elapsed time to be equal to or greater than the third stop threshold (NO in step S31).

When the elapsed time becomes equal to or greater than the third stop threshold value (YES in step S31), the combustion air supply device 7 is stopped (step S32). The third stop threshold is defined as a time during which the gas remaining in the combustor 4 can be purged into the atmosphere after the fuel cell bypass valve 22 as the fuel gas valve is closed. That is, in step S31, the amount of combustion air supplied after the fuel cell bypass valve 22 is closed is equal to or greater than the supply amount (threshold supply amount) that allows the gas remaining in the combustor 4 to be purged into the atmosphere. The above-described step S31, which is for the purpose of determining whether or not, has been determined based on the elapsed time, is an example.
Thus, the stop process of the fuel cell system 102 is completed.

  According to the fuel cell system of the present embodiment described above, when the source gas is also supplied to the hydrogen generator 101 in the cathode purge, the water continues to be burned by the combustion continuation operation after the supply of the source and water is stopped. Since most of the volume expanded by the evaporation is discharged into the atmosphere, even if the raw material valve 52 downstream of the raw material supplier 2 is opened, the reverse flow of water vapor from the inside of the reformer 10 to the raw material path 13 side. It is possible to reduce the amount of occurrence of backflow or the amount of backflow. Therefore, the possibility that water vapor is blocked in the raw material path 13 and the raw material gas cannot be supplied properly can be reduced. Further, since the combustion air supply device 7 continues to operate until the cathode purge is performed, the temperature inside the reformer 10 can be quickly lowered via the combustor 4 (exactly the combustion exhaust gas path). Thereby, the time until the cathode purge is performed can be shortened. As a result, the time during which the anode of the fuel cell 17 is placed in a hydrogen atmosphere and the cathode is placed in an oxygen atmosphere is shortened, deterioration of the fuel cell 17 can be suppressed, and the stop processing time of the fuel cell system 102 is shortened. be able to.

[Modification 1]
In the above, the fuel gas inlet valve 21 and the fuel cell bypass are used as the gas path switching means for switching the supply destination of the gas (fuel gas or combustible gas) sent from the hydrogen generator main body 1 between the fuel cell 17 and the fuel gas discharge path 41. Although the valve 22 is used, in this modification, instead of this, a three-way valve that switches the supply destination of the gas delivered from the hydrogen generator main body 1 between the fuel cell 17 and the fuel gas discharge path 41 is a fuel gas supply path. 16 and the fuel cell bypass path 20, and the fuel gas valve 6 according to the first embodiment is connected to the fuel cell discharge path 41 on the downstream side of the connection part with the fuel cell bypass path 20. A corresponding on-off valve (hereinafter referred to as a fuel gas valve) is provided. The fuel gas valve functioning as the fuel gas valve 6 is not limited to the above arrangement as long as it is provided in a path from the outlet of the hydrogen generator main body 1 to the combustor 4 via the fuel cell bypass valve.
In this configuration, when the fuel cell system 102 is activated, the three-way valve is switched to supply the gas delivered from the hydrogen generator main body 1 to the fuel gas discharge path 41 and the fuel gas valve is opened. The fuel gas outlet valve 23 remains closed. Further, during the power generation operation of the fuel cell system 102, the three-way valve is switched from that state so as to supply the gas sent from the hydrogen generator main body 1 to the fuel cell 17, and the fuel gas outlet valve 23 is opened. Further, during the stop process of the fuel cell system 102, the three-way valve is switched from that state to supply the gas sent from the hydrogen generator main body 1 to the fuel cell bypass path 20 and the fuel gas outlet valve 23 is closed. . Then, after the misfire of the combustor 4 is detected, the fuel gas valve is closed. Even with such a configuration, the same effect as described above can be obtained.

[Modification 2]
In this modified example, instead of the fuel cell bypass valve 22 and the fuel gas outlet valve 23, the gas path switching means uses a fuel cell bypass path 20 as a source of gas (fuel gas or combustible gas) supplied to the combustor 4. A three-way valve that switches between the fuel cell 17 and the fuel cell bypass path 20 and the fuel gas discharge path 41 is disposed at the downstream of the fuel cell discharge path 41 and the fuel cell bypass path 20. The fuel gas valve is disposed on the side portion. The fuel gas valve is not limited to the above arrangement as long as it is provided in a path from the outlet of the hydrogen generator main body 1 to the combustor 4 via the fuel cell bypass valve.
In this configuration, when the fuel cell system 102 is activated, the three-way valve is switched so that the gas source supplied to the combustor 4 is the fuel cell bypass path 20 and the fuel gas valve is opened. The fuel gas inlet valve 21 remains closed. As a result, gas (incomplete fuel gas) delivered from the hydrogen generator main body 1 is supplied to the combustor 4 via the fuel cell bypass path 20. Further, during the power generation operation of the fuel cell system 102, the three-way valve is switched from that state so that the source of the gas supplied to the combustor 4 is the fuel cell 17, and the fuel gas inlet valve 21 is opened. As a result, the fuel gas delivered from the hydrogen generator main body 1 is supplied to the combustor 4 via the fuel cell 17. Furthermore, during the stop process of the fuel cell system 102, the three-way valve is switched from that state so that the gas supply source of the gas supplied to the combustor 4 becomes the fuel cell bypass path 20, and the fuel gas inlet valve 21 is closed. . As a result, the combustible gas delivered from the hydrogen generator main body 1 is supplied to the combustor 4 via the fuel cell bypass path 20. Then, after the misfire of the combustor 4 is detected, the fuel gas valve is closed. Even with such a configuration, the same effect as described above can be obtained.

[Modification 3]
In the above, in the combustible gas combustion process (step S21) in the hydrogen generator 101, the fuel cell bypass valve 22 is opened, and the combustible gas pushed out from the reformer 10 is supplied to the combustor 4 through the fuel cell bypass path 20. The On the other hand, in this modification, in the combustible gas combustion process (step S21) in the hydrogen generator 101, the fuel cell bypass valve 22 is closed and the fuel gas inlet valve 21 and the fuel gas outlet valve 23 are opened. As a result, the combustible gas pushed out from the reformer 10 is supplied to the combustor 4 through the fuel gas supply path 16, the internal fuel gas path 43 of the fuel cell 17, and the fuel gas discharge path 41. Will continue to burn. In this case, the fuel gas inlet valve 21 and the fuel gas outlet valve 23 function as fuel gas valves. Therefore, when misfire is detected by the misfire detector 8, either or both of the fuel gas inlet valve 21 and the fuel gas outlet valve 23 are closed as the fuel gas valve. Other points are the same as above. Even with such a configuration, the same effect as described above can be obtained.

  In the above description, the amount of combustion air supplied after closing at least one of the fuel gas inlet valve 21 and the fuel gas outlet valve 22 as the fuel gas valve causes the gas remaining in the combustor 4 to enter the atmosphere. Whether or not the supply amount (threshold supply amount) that can be purged has been exceeded is determined by the elapsed time since the operation amount of the combustion air supply device 7 is increased. Good. Examples of such parameters include the elapsed time after closing at least one of the fuel gas inlet valve 21 and the fuel gas outlet valve 22 as a fuel gas valve.

  The hydrogen generator according to the present invention is useful as a hydrogen generator used in a fuel cell system.

  The fuel cell system according to the present invention is useful as a fuel cell system used in household applications.

DESCRIPTION OF SYMBOLS 1 Hydrogen generator main body 2 Raw material supply device 3 Water supply device 4 Combustor 5 Fuel gas path 6 Fuel gas valve 7 Air supply device 8 Misfire detector 9 Controller 10 Reformer 11 Transformer 12 CO remover 13 Raw material route 14 Water supply path 15 Combustion air supply path 16 Fuel gas supply path 17 Fuel cell 18 Oxidant gas supply path 19 Oxidant gas supplier 20 Fuel cell bypass path 21 Fuel gas inlet valve 22 Fuel cell bypass valve 23 Fuel gas outlet valve 24 Oxidation Agent gas discharge path 25 Cathode purge gas inlet valve 26 Cathode purge gas outlet valve 27 Temperature detector 28 Reformer 29 Combustor 32 Raw material valve 33 Fuel gas valve 34 Reforming temperature detector 35 Transformation temperature detector 36 Pressure detector 41 Fuel gas Discharge path 42 Oxidant gas valve 43 Internal fuel gas path 44 Internal oxidant gas path 45 Cathode purge gas path 51 Ignition 52 Raw material valve 53 Timer 101 Hydrogen generator 102 Fuel cell system

Claims (8)

A hydrogen generator main body for generating a fuel gas containing hydrogen by a steam reforming reaction between a raw material gas and steam;
A raw material supplier for supplying the raw material gas to the hydrogen generator main body;
A water supply for supplying water for the steam reforming reaction to the hydrogen generator main body;
The fuel generator is connected to the fuel gas outlet of the hydrogen generator main body through a fuel gas path, and the heat required for the steam reforming reaction is supplied to the hydrogen generator main body by burning the gas sent from the fuel gas outlet. A combustor to supply,
An air supply for supplying combustion air to the combustor;
A controller for controlling operations of the raw material supplier, the water supplier, and the air supplier;
A fuel gas valve provided in the fuel gas path;
A misfire detector for detecting misfire in the combustor, and
When the stop process is started in a state where the combustor is burning the gas flowing in through the fuel gas path, the controller supplies the raw material gas by the raw material supplier and the water supplier. The supply of water is stopped, and then the supply of the combustion air by the air supply device is continued so that the combustion continues in the combustor. When the misfire is detected by the misfire detector, the fuel gas valve is closed. A hydrogen generator configured as described above.   The controller is configured to open the fuel gas valve so that an outlet of the fuel gas of the hydrogen generator main body communicates with the combustor through the fuel gas path during a period in which the combustion continues. The hydrogen generator according to claim 1.   The hydrogen generator according to claim 1, wherein the controller is configured to continue supplying the combustion air by the air supply unit after closing the fuel gas valve.   The hydrogen generator according to claim 1, wherein the controller is configured to increase an operation amount of the air supply unit after closing the fuel gas valve. A hydrogen generator main body for generating a fuel gas containing hydrogen by a steam reforming reaction between a raw material gas and steam;
A raw material supplier for supplying the raw material gas to the hydrogen generator main body;
A water supply for supplying water for the steam reforming reaction to the hydrogen generator main body;
The fuel generator is connected to the fuel gas outlet of the hydrogen generator main body through a fuel gas path, and the heat required for the steam reforming reaction is supplied to the hydrogen generator main body by burning the gas sent from the fuel gas outlet. A combustor to supply,
An air supply for supplying combustion air to the combustor;
A controller for controlling operations of the raw material supplier, the water supplier, and the air supplier;
An igniter provided in the combustor,
When the stop process is started in a state where the combustor is burning the gas flowing in through the fuel gas path, the controller supplies the raw material gas by the raw material supplier and the water supplier. The supply of water is stopped, and then the supply of combustion air by the air supply is continued so that the combustion continues in the combustor,
A hydrogen generator configured to ignite the igniter after the supply of the raw material gas by the raw material supplier and the supply of water by the water supplier are stopped.   6. The apparatus according to claim 5, further comprising a misfire detector that detects misfire in the combustor, wherein the controller is configured to stop the ignition operation of the igniter when the misfire is detected by the misfire detector. Hydrogen generator.   A fuel gas valve provided in the fuel gas path, wherein the controller is configured so that the fuel gas outlet of the hydrogen generator main body is connected to the combustor through the fuel gas path during a period in which the combustion continues. The hydrogen generator according to claim 5 or 6, wherein the fuel gas valve is configured to open so as to be communicated. Fuel cell system comprising a hydrogen generator according to any one of claims 1 to 7, and a fuel cell for generating electric power using the fuel gas supplied from the hydrogen generator.

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