Fuel cell system

Abstract

To provide a fuel cell system capable of appropriately producing a state that is determined, by a gas meter, to satisfy a non-leakage condition without sacrificing advantages for users as much as possible.SOLUTION: Provided is a fuel cell system S in which a control device 22 performs a leakage determination avoidance process including a standby process a preset number of times or more within a predetermined processing target period having the same length as a leakage determination period. In the standby process, a power generation state where power generation at a fuel cell part FC is performed while a reformed gas is generated after an amount of a raw fuel gas at least a reforming part 7 receives from a gas meter 1 is controlled to such an amount that the gas meter 1 determines that a non-leakage condition is not satisfied, is changed to a standby state where the amount of the raw fuel gas at least the reforming part 7 receives from the gas meter 1 to such an amount that the gas meter 1 determines that the non-leakage condition is satisfied, and then, the standby state is continued for a predetermined standby period longer than a setting determination period for the gas meter 1 to determine whether or not the non-leakage condition is satisfied.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a fuel cell system including a reforming unit that steam-reforms a raw fuel gas containing hydrocarbons supplied via a gas meter to generate a reformed gas containing hydrogen, a fuel cell unit having an anode to which the reformed gas generated in the reforming unit is supplied and a cathode to which oxygen gas is supplied, a combustion unit that burns combustion components contained in the anode exhaust gas discharged from the anode, and a control device.

Background Art

[0002] A gas meter such as a so-called microcomputer meter is configured to activate an alarm or shut off the supply of the raw fuel gas when a state satisfying a non-leakage condition indicating that the flow rate of the raw fuel gas is zero or low does not occur a set number of times during a leakage determination period.

[0003] Patent Document 1 describes a technique for avoiding the activation of an alarm or shutting off the supply of the raw fuel gas by the gas meter as described above by intentionally creating a period during which the fuel cell system does not consume the raw fuel gas. Specifically, the fuel cell system is controlled to stop for one day every 27 days (three days before the elapse of 30 days, which is the leakage determination period).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] As described in Patent Document 1, by stopping the power generation operation of the fuel cell system for one day, the possibility of determining that the gas meter satisfies the non-leakage condition increases. However, during that time, the supply of power and heat from the fuel cell system is stopped, so the benefits to the user are impaired.

[0006] The present invention has been made in view of the above problems, and an object thereof is to provide a fuel cell system capable of appropriately generating a state determined by a gas meter to satisfy a non-leakage condition without impairing the benefits to the user as much as possible.

Means for Solving the Problems

[0007] A characteristic configuration of a fuel cell system according to the present invention for achieving the above object includes a reforming unit that steam-reforms a raw fuel gas containing hydrocarbons supplied via a gas meter to generate a reformed gas containing hydrogen, an anode to which the reformed gas generated in the reforming unit is supplied, and a cathode to which oxygen gas is supplied. A fuel cell unit, a combustion unit that burns combustion components contained in the anode exhaust gas discharged from the anode, and a control device, wherein the combustion heat generated in the combustion unit is used for steam reforming by the reforming unit, The gas meter is configured to operate an alarm or shut off the supply of the raw fuel gas when a state satisfying a non-leakage condition indicating that the flow rate of the raw fuel gas is zero or low does not occur a set number of times during a leakage determination period. A fuel cell system, An adsorption section having an adsorbent capable of adsorbing the raw fuel gas upstream of the reforming section and a temperature adjustment section capable of adjusting the temperature of the adsorbent is provided. The control device shifts from a power generation state in which power generation is performed by the fuel cell unit while reformed gas is generated with the amount of the raw fuel gas received by at least the reforming unit from the gas meter being set to an amount for which the gas meter is determined not to satisfy the non-leakage condition within a predetermined processing target period having the same length as the leakage determination period, to a standby state in which the amount of the raw fuel gas received by at least the reforming unit from the gas meter is set to an amount for which the gas meter is determined to satisfy the non-leakage condition, and includes a leakage determination avoidance process in which the standby state is continued for a predetermined standby period longer than a set determination period that is a period for which the gas meter determines whether or not the non-leakage condition is satisfied, and performs the leakage determination avoidance process Yes. While the control device is performing the standby process, the temperature adjustment section adjusts the temperature of the adsorbent to desorb the raw fuel gas from the adsorbent. at a point. Here, the fuel cell unit may include a solid oxide type power generation cell having the anode, the cathode, and an electrolyte layer using a solid oxide provided therebetween. Further, an information reception unit that receives gas meter information capable of specifying the set determination period, the leakage determination period, and the set number of times of the gas meter is provided, and the control device may perform the leakage determination avoidance process based on the gas meter information received by the information reception unit. According to the above characteristic configuration, the control device determines that, within a predetermined processing target period having the same length as the leakage determination period, at least with respect to the amount of raw fuel gas received by the reforming section from the gas meter, the gas meter satisfies the non-leakage condition. The control device performs a leakage determination avoidance process including a standby process that continues for a predetermined standby period longer than a setting determination period, which is a period for the gas meter to determine whether the non-leakage condition is satisfied, for a set number of times or more. As a result, the possibility that the gas meter determines that a state satisfying the non-leakage condition has occurred a set number of times during the leakage determination period increases. Further, at least for the setting determination period, at least with respect to the amount of raw fuel gas received by the reforming section from the gas meter, the gas meter may be set to an amount that satisfies the non-leakage condition. This setting determination period is a value set for each gas meter. If this setting determination period is short, the standby period may also be short. Therefore, it is not necessary to stop the fuel cell system for one day as in the prior art. In addition, according to the above characteristic configuration, the raw fuel gas desorbed from the adsorbent during the standby process is diffused from the reforming section to the anode. Therefore, during the standby process of the leakage determination avoidance process, the intrusion of air or the like from the outside into the anode or the like is suppressed. Therefore, it is possible to provide a fuel cell system that can appropriately generate a state determined by the gas meter to satisfy the non-leakage condition without significantly impairing the merits of the user.

[0008] A characteristic configuration of a fuel cell system according to the present invention for achieving the above object includes a reforming section that steam-reforms a raw fuel gas containing hydrocarbons supplied via a gas meter to generate a reformed gas containing hydrogen, an anode to which the reformed gas generated in the reforming section is supplied, and a cathode to which oxygen gas is supplied. A fuel cell section, a combustion section that burns combustion components contained in the anode exhaust gas discharged from the anode, and a control device, wherein the combustion heat generated in the combustion section is used for steam reforming by the reforming section. The fuel cell system is configured such that when a state satisfying a non-leakage condition indicating that the flow rate of the raw fuel gas is zero or small does not occur the set number of times during a leakage determination period, an alarm is activated or the supply of the raw fuel gas is shut off. The adsorption section has an adsorbent capable of adsorbing the raw fuel gas upstream of the reforming section and a temperature adjustment section capable of adjusting the temperature of the adsorbent. During a predetermined processing target period having the same length as the leakage determination period, the control device shifts from a power generation state in which power generation is performed in the fuel cell section while generating reformed gas with an amount of the raw fuel gas received by at least the reforming section from the gas meter set to an amount for which the gas meter determines that the non-leakage condition is not satisfied, to a standby state in which the amount of the raw fuel gas received by at least the reforming section from the gas meter is set to an amount for which the gas meter determines that the non-leakage condition is satisfied, and continues the standby process for a predetermined standby period longer than a set determination period, which is a period for the gas meter to determine whether or not the non-leakage condition is satisfied, for the set number of times or more. This is a leakage determination avoidance process. In the standby process, the control device causes the temperature adjustment section to adjust the temperature of the adsorbent and perform power generation in the fuel cell section while generating reformed gas using the raw fuel gas desorbed from the adsorbent. at a point. Here, the fuel cell section may include a solid oxide type power generation cell having the anode, the cathode, and an electrolyte layer using a solid oxide provided therebetween. The system also includes an information reception section that receives gas meter information capable of specifying the set determination period, the leakage determination period, and the set number of times of the gas meter. The control device may perform the leakage determination avoidance process based on the gas meter information received by the information reception section. According to the above characteristic configuration, within a predetermined processing target period having the same length as the leakage determination period, the control device sets a standby state such that, at least with respect to the amount of the raw fuel gas received by the reforming unit from the gas meter, the amount is such that the gas meter determines that the non-leakage condition is satisfied, and continues the standby process for a predetermined standby period longer than the setting determination period, which is the period for the gas meter to determine whether or not the non-leakage condition is satisfied, for more than the set number of times. As a result, the possibility that the gas meter determines that the state in which the non-leakage condition is satisfied occurs the set number of times during the leakage determination period increases. Further, at least for at least the setting determination period, at least with respect to the amount of the raw fuel gas received by the reforming unit from the gas meter, the amount may be such that the gas meter determines that the non-leakage condition is satisfied. This setting determination period is a value set for each gas meter, but if this setting determination period is short, the above standby period may also be short. Therefore, it is not necessary to stop the fuel cell system for one day as in the prior art. In addition, according to the above characteristic configuration, in the standby process, the reforming unit can generate a reformed gas using the raw fuel gas desorbed from the adsorption unit, and can cause power generation in the fuel cell unit with the reformed gas. Therefore, it is possible to provide a fuel cell system capable of appropriately generating a state determined by the gas meter to satisfy the non-leakage condition without significantly impairing the merits of the user.

[0009] A characteristic configuration of a fuel cell system according to the present invention for achieving the above object includes a reforming unit that steam-reforms a raw fuel gas containing hydrocarbons supplied via a gas meter to generate a reformed gas containing hydrogen, a fuel cell unit having an anode to which the reformed gas generated by the reforming unit is supplied and a cathode to which oxygen gas is supplied, a combustion unit that burns a combustion component contained in the anode exhaust gas discharged from the anode, and a control device, wherein the combustion heat generated in the combustion unit is used for steam reforming by the reforming unit. The gas meter is configured to operate an alarm or cut off the supply of the raw fuel gas when a state in which the non-leakage condition indicating that the flow rate of the raw fuel gas is zero or low does not occur the set number of times during the leakage determination period. This is a fuel cell system. It includes an adsorption unit having an adsorbent capable of adsorbing the raw fuel gas upstream of the reforming unit and a temperature adjustment unit capable of adjusting the temperature of the adsorbent. The control device shifts from a power generation state in which power generation is performed by the fuel cell unit while generating reformed gas with an amount of the raw fuel gas received by at least the reforming unit from the gas meter set to an amount for which the gas meter is determined not to satisfy the non-leakage condition within a predetermined processing target period having the same length as the leakage determination period, to a standby state in which the amount of the raw fuel gas received by at least the reforming unit from the gas meter is set to an amount for which the gas meter is determined to satisfy the non-leakage condition, and continues the standby process for a predetermined standby period longer than a set determination period, which is a period for the gas meter to determine whether or not the non-leakage condition is satisfied, for the leakage determination avoidance process a number of times equal to or greater than the set number of times. In the standby process, the control device sets the amount of the raw fuel gas received by the reforming unit from the gas meter to zero, and causes the fuel cell unit to perform power generation while generating reformed gas using the raw fuel gas desorbed from the adsorbent by adjusting the temperature of the adsorbent by the temperature adjustment unit. It is at the point. Here, the fuel cell unit may include a solid oxide type power generation cell having the anode, the cathode, and an electrolyte layer using a solid oxide provided therebetween. Further, an information reception unit that receives gas meter information capable of specifying the set determination period, the leakage determination period, and the set number of times of the gas meter is provided, and the control device may perform the leakage determination avoidance process based on the gas meter information received by the information reception unit. According to the above-described characteristic configuration, the control device sets a standby state in which, within a predetermined processing target period having the same length as the leakage determination period, at least with respect to the amount of raw fuel gas received by the reforming unit from the gas meter, the amount is set such that the gas meter determines that the non-leakage condition is satisfied, and continues the standby process for a predetermined standby period longer than the setting determination period, which is a period for the gas meter to determine whether or not the non-leakage condition is satisfied, for more than the set number of times. As a result, the possibility that the gas meter determines that the state in which the non-leakage condition is satisfied occurs the set number of times during the leakage determination period is increased. Further, at least for at least the setting determination period, at least with respect to the amount of raw fuel gas received by the reforming unit from the gas meter, the amount may be set such that the gas meter determines that the non-leakage condition is satisfied. This setting determination period is a value set for each gas meter, but if this setting determination period is short, the above standby period may also be short. Therefore, it is not necessary to stop the fuel cell system for one day as in the conventional case. In addition, according to the above-described characteristic configuration, in the standby process, while making the amount of raw fuel gas received by the reforming unit from the gas meter zero, the reforming unit can generate reformed gas using the raw fuel gas desorbed from the adsorption unit, and can cause power generation in the fuel cell unit with the reformed gas. Therefore, it is possible to provide a fuel cell system that can appropriately generate a state determined by the gas meter to satisfy the non-leakage condition without impairing the user's merits as much as possible.

[0010] A characteristic configuration of a fuel cell system according to the present invention for achieving the above object includes a reforming unit that steam-reforms raw fuel gas containing hydrocarbons supplied via a gas meter to generate reformed gas containing hydrogen, a fuel cell unit having an anode to which the reformed gas generated by the reforming unit is supplied and a cathode to which oxygen gas is supplied, a combustion unit that burns combustion components contained in anode exhaust gas discharged from the anode, and a control device, wherein the combustion heat generated in the combustion unit is used for steam reforming by the reforming unit. The gas meter is a fuel cell system configured to operate an alarm or shut off the supply of the raw fuel gas when a state satisfying a non-leakage condition indicating that the flow rate of the raw fuel gas is zero or low does not occur the set number of times during the leakage determination period. During a predetermined processing target period having the same length as the leakage determination period, the control device generates reformed gas with an amount such that the gas meter is determined not to satisfy the non-leakage condition for at least the amount of the raw fuel gas received by the reforming unit from the gas meter, while performing power generation in the fuel cell unit. Then, the control device shifts from the power generation state to a standby state with an amount such that the gas meter is determined to satisfy the non-leakage condition for at least the amount of the raw fuel gas received by the reforming unit from the gas meter, and continues the standby state for a predetermined standby period longer than the set determination period, which is the period for the gas meter to determine whether the non-leakage condition is satisfied, including a standby process. The control device performs the leakage determination avoidance process including the standby process more than the set number of times. At any point in time, the control device determines the implementation schedule of the leakage determination avoidance process including the standby process so that the standby process is performed a predetermined number of planned executions more than the set number of times within a period having the same length as the future leakage determination period from that point. The control device monitors the operating state of the gas consumption device that consumes the raw fuel gas supplied via the gas meter. When the gas consumption device consumes the raw fuel gas during the standby process of the leakage determination avoidance process, the number of planned executions is increased. Here, the fuel cell unit may include a solid oxide type power generation cell having the anode, the cathode, and an electrolyte layer using a solid oxide provided therebetween. The control device may further include an information reception unit that receives gas meter information capable of specifying the set determination period, the leakage determination period, and the set number of times of the gas meter, and perform the leakage determination avoidance process based on the gas meter information received by the information reception unit. According to the above-described characteristic configuration, the control device sets a standby process that includes a leakage determination avoidance process of continuing for a predetermined standby period longer than a setting determination period, which is a period for the gas meter to determine whether or not a non-leakage condition is satisfied, in a predetermined processing target period having the same length as the leakage determination period, such that at least the amount of the raw fuel gas received by the reforming unit from the gas meter is an amount for which the gas meter determines that the non-leakage condition is satisfied. As a result, the possibility that the gas meter determines that a state in which the non-leakage condition is satisfied has occurred a set number of times during the leakage determination period is increased. Further, at least for the setting determination period, at least the amount of the raw fuel gas received by the reforming unit from the gas meter may be set to an amount for which the gas meter determines that the non-leakage condition is satisfied. This setting determination period is a value set for each gas meter, and if this setting determination period is short, the above standby period may also be short. Therefore, it is not necessary to stop the fuel cell system for one day as in the prior art. In addition, according to the above-described characteristic configuration, the possibility that the gas meter determines that a state in which the non-leakage condition is satisfied has occurred a set number of times during the leakage determination period is increased. Furthermore, according to the above-described characteristic configuration, even if the gas consumption device consumes the raw fuel gas during the standby process of the leakage determination avoidance process, by increasing the planned number of executions, the possibility that the gas meter determines that a state in which the non-leakage condition is satisfied has occurred a set number of times during the leakage determination period is increased. Therefore, it is possible to provide a fuel cell system that can appropriately generate a state determined by the gas meter to satisfy the non-leakage condition without significantly impairing the merits of the user.

[0011] A characteristic configuration of a fuel cell system according to the present invention for achieving the above object includes a reforming unit that steam-reforms a raw fuel gas containing hydrocarbons supplied via a gas meter to generate a reformed gas containing hydrogen, a fuel cell unit having an anode to which the reformed gas generated by the reforming unit is supplied and a cathode to which oxygen gas is supplied, a combustion unit that burns a combustion component contained in the anode exhaust gas discharged from the anode, and a control device, wherein the combustion heat generated in the combustion unit is used for steam reforming by the reforming unit. The fuel cell system is configured such that the gas meter alarms or shuts off the supply of the raw fuel gas when a state satisfying a non-leakage condition indicating that the flow rate of the raw fuel gas is zero or small does not occur the set number of times during a leakage determination period. The control device performs power generation in the fuel cell unit while generating reformed gas with an amount of the raw fuel gas received by at least the reforming unit from the gas meter set to an amount at which the gas meter is determined not to satisfy the non-leakage condition within a predetermined processing target period having the same length as the leakage determination period. Then, the control device shifts to a standby state in which the amount of the raw fuel gas received by at least the reforming unit from the gas meter is set to an amount at which the gas meter is determined to satisfy the non-leakage condition, and continues the standby state for a predetermined standby period longer than a set determination period, which is a period for the gas meter to determine whether the non-leakage condition is satisfied, in a leakage determination avoidance process including the standby process for the set number of times or more. At any point in time, the control device determines an execution schedule of the leakage determination avoidance process including the standby process so that the standby process is performed the set number of times or more, which is a predetermined planned number of executions, within a period having the same length as the future leakage determination period from that point. The control device monitors the operating state of a gas consumption device that consumes the raw fuel gas supplied via the gas meter. When the gas consumption device consumes the raw fuel gas during the standby process of the leakage determination avoidance process, the control device extends the length of the standby period of the currently ongoing standby process or the standby process to be performed in the future. It is at the point. Here, the fuel cell unit may include a solid oxide type power generation cell having the anode, the cathode, and an electrolyte layer using a solid oxide provided therebetween. Further, the system may include an information reception unit that receives gas meter information capable of specifying the set determination period, the leakage determination period, and the set number of times of the gas meter. The control device may perform the leakage determination avoidance process based on the gas meter information received by the information reception unit. According to the above characteristic configuration, the control device sets a standby state in a predetermined processing target period having the same length as the leakage determination period, such that the amount of the raw fuel gas received by at least the reforming unit from the gas meter is an amount for which the gas meter determines that the non-leakage condition is satisfied, and continues a standby process for a predetermined standby period longer than the setting determination period, which is a period for the gas meter to determine whether or not the non-leakage condition is satisfied, for the setting number of times or more. As a result, the possibility that the gas meter determines that the state in which the non-leakage condition is satisfied has occurred the setting number of times during the leakage determination period is increased. Further, for at least the setting determination period, the amount of the raw fuel gas received by at least the reforming unit from the gas meter may be set to an amount for which the gas meter determines that the non-leakage condition is satisfied. This setting determination period is a value set for each gas meter, but if this setting determination period is short, the above standby period may also be short. Therefore, it is not necessary to stop the fuel cell system for one day as in the prior art. In addition, according to the above characteristic configuration, the possibility that the gas meter determines that the state in which the non-leakage condition is satisfied has occurred the setting number of times during the leakage determination period is increased. Furthermore, according to the above characteristic configuration, even if the gas consumption device consumes the raw fuel gas during the standby process of the leakage determination avoidance process, by extending the length of the standby period of the currently ongoing standby process or the standby process to be performed in the future, the possibility that the gas meter determines that the state in which the non-leakage condition is satisfied has occurred the setting number of times during the leakage determination period is increased. Therefore, it is possible to provide a fuel cell system capable of appropriately generating a state determined by the gas meter to satisfy the non-leakage condition without impairing the user's merits as much as possible.

[0012] A characteristic configuration of a fuel cell system according to the present invention for achieving the above object includes a reforming unit that steam-reforms a raw fuel gas containing hydrocarbons supplied via a gas meter to generate a reformed gas containing hydrogen, a fuel cell unit having an anode to which the reformed gas generated by the reforming unit is supplied and a cathode to which oxygen gas is supplied, a combustion unit that burns a combustion component contained in the anode exhaust gas discharged from the anode, and a control device, wherein the combustion heat generated in the combustion unit is used for steam reforming by the reforming unit. The fuel cell system is configured such that the gas meter activates an alarm or shuts off the supply of the raw fuel gas when a state satisfying a non-leakage condition indicating that the flow rate of the raw fuel gas is zero or low does not occur the set number of times during a leakage determination period. During a predetermined processing target period having the same length as the leakage determination period, the control device shifts from a power generation state in which power generation is performed in the fuel cell unit while generating reformed gas with an amount of the raw fuel gas received by at least the reforming unit from the gas meter set to an amount for which the gas meter determines that the non-leakage condition is not satisfied, to a standby state in which the amount of the raw fuel gas received by at least the reforming unit from the gas meter is set to an amount for which the gas meter determines that the non-leakage condition is satisfied, and continues the standby state for a predetermined standby period longer than a set determination period, which is a period for which the gas meter determines whether or not the non-leakage condition is satisfied, and performs the leakage determination avoidance process including the standby process the set number of times or more. The system includes an information reception unit that receives gas meter information capable of specifying the set determination period, the leakage determination period, and the set number of times of the gas meter. The control device performs the leakage determination avoidance process based on the gas meter information received by the information reception unit. It is at the point. Here, the fuel cell unit may include a solid oxide type power generation cell having the anode, the cathode, and an electrolyte layer using a solid oxide provided therebetween. According to the above characteristic configuration, within a predetermined processing target period having the same length as the leakage determination period, the control device maintains a standby state in which at least the amount of raw fuel gas received by the reforming unit from the gas meter is set to an amount for which the gas meter determines that the non-leakage condition is satisfied, for a predetermined standby period longer than the setting determination period, which is the period for the gas meter to determine whether or not the non-leakage condition is satisfied. The control device performs the leakage determination avoidance process including this standby process more than the set number of times. As a result, the possibility that the gas meter determines that the state satisfying the non-leakage condition has occurred the set number of times during the leakage determination period increases. Further, for at least the setting determination period, at least the amount of raw fuel gas received by the reforming unit from the gas meter may be set to an amount for which the gas meter determines that the non-leakage condition is satisfied. This setting determination period is a value set for each gas meter, and if this setting determination period is short, the above standby period may also be short. Therefore, it is not necessary to stop the fuel cell system for one day as in the prior art. In addition, the control device can perform the leakage determination avoidance process based on the gas meter information received by the information receiving unit. Therefore, it is possible to provide a fuel cell system capable of appropriately generating a state determined by the gas meter to satisfy the non-leakage condition without impairing the user's merits as much as possible.

[0013] Another characteristic configuration of the fuel cell system according to the present invention is that, in the standby process, the control device sets the amount of the raw fuel gas received by the reforming unit from the gas meter to zero and stops power generation in the fuel cell unit. According to the above characteristic configuration, since the amount of the raw fuel gas received by the reforming unit from the gas meter is set to zero, the possibility that the gas meter determines that the non-leakage condition is satisfied during the standby process increases.

[0014] Still another characteristic configuration of the fuel cell system according to the present invention is that the control device, as the leakage determination avoidance process, performs a pre-process of stopping power generation in the fuel cell unit while continuing to receive the raw fuel gas from the gas meter by the reforming unit, performs the standby process after the pre-process, and burns the anode exhaust gas discharged from the anode in the combustion unit during the pre-process. According to the above characteristic configuration, before the standby process of setting the amount of the raw fuel gas received by the reforming unit from the gas meter to zero, a preprocess is performed to stop power generation in the fuel cell unit while the reforming unit continues to receive the raw fuel gas from the gas meter. That is, at the start time of the standby process, the raw fuel gas is in a state of being filled at a high concentration from the reforming unit through the anode of the fuel cell unit to the combustion unit. Therefore, during the subsequent standby process, the intrusion of air or the like from the outside into the anode or the like and the oxidative degradation of the anode are suppressed. Further, since the anode exhaust gas (i.e., high-concentration raw fuel gas) discharged from the anode during the preprocess is burned in the combustion unit, at the start time of the standby process, the internal temperature of, for example, the hot module that houses the reforming unit, the fuel cell unit, and the combustion unit becomes high due to the combustion heat released from the combustion unit. As a result, even if the temperature of the reforming unit decreases during the subsequent standby process, the temperature at the end time of the standby process can be made high, and the deterioration effect on the fuel cell unit due to the temperature change can be suppressed.

[0015] Still another characteristic configuration of the fuel cell system according to the present invention is that the control device, as the leakage determination avoidance process, after the standby process, performs a post-process of stopping power generation in the fuel cell unit while the reforming unit receives the raw fuel gas from the gas meter and generates the reformed gas, and burns the anode exhaust gas discharged from the anode during the post-process in the combustion unit. According to the above characteristic configuration, even if gas intrudes from the outside into the anode or the like during the standby process, after these gases are discharged by the raw fuel gas by the post-process, power generation in the fuel cell unit is restarted. Further, after the temperature rises by burning the anode exhaust gas (i.e., high-concentration raw fuel gas) discharged from the anode during the post-process in the combustion unit, power generation in the fuel cell unit can be restarted.

[0016] Still another characteristic configuration of the fuel cell system according to the present invention is that the control device continues to receive water for the steam reforming in the reforming unit while performing the leakage determination avoidance process. According to the above characteristic configuration, during the leakage determination avoidance process, a mixed gas of water vapor and the fuel gas filled in the reforming section is supplied from the reforming section to the anode. Therefore, during the standby process of the leakage determination avoidance process, the intrusion of air or the like into the anode or the like from the outside and the oxidative degradation of the anode are suppressed. Further, during the leakage determination avoidance process or immediately after the restart of power generation, a decrease in the S / C (steam / carbon ratio) of the gas supplied to the anode is suppressed.

[0017] Yet another characteristic configuration of the fuel cell system according to the present invention includes an adsorption section having an adsorbent capable of adsorbing the raw fuel gas upstream of the reforming section and a temperature adjustment section capable of adjusting the temperature of the adsorbent. The control device is configured to desorb the raw fuel gas from the adsorbent by adjusting the temperature of the adsorbent by the temperature adjustment section while performing the standby process.

[0018] According to the above characteristic configuration, the raw fuel gas desorbed from the adsorbent during the standby process diffuses from the reforming section to the anode. Therefore, during the standby process of the leakage determination avoidance process, the intrusion of air or the like from the outside into the anode or the like is suppressed.

[0019] Another characteristic configuration of the fuel cell system according to the present invention is that, in the standby process, the control device receives, from the gas meter, an amount of the raw fuel gas that allows the gas meter to determine that the non-leakage condition is satisfied in the reforming section, generates the reformed gas, and causes power generation in the fuel cell section while generating the reformed gas.

[0020] According to the above characteristic configuration, since the amount of the raw fuel gas received by the reforming section from the gas meter is set to an amount that allows the gas meter to determine that the non-leakage condition is satisfied, the possibility that the gas meter determines that the non-leakage condition is satisfied increases during the standby process. Further, during the standby process, the reforming section can receive the raw fuel gas from the gas meter, generate the reformed gas, and perform power generation in the fuel cell section while generating the reformed gas.

[0021] Another characteristic configuration of the fuel cell system according to the present invention includes an adsorption section having an adsorbent capable of adsorbing the raw fuel gas upstream of the reforming section and a temperature adjustment section capable of adjusting the temperature of the adsorbent. In the standby process, the control device adjusts the temperature of the adsorbent by the temperature adjustment section, generates the reformed gas using the raw fuel gas desorbed from the adsorbent, and causes power generation in the fuel cell section.

[0022] According to the above characteristic configuration, in the standby process, the reforming section can generate the reformed gas using the raw fuel gas desorbed from the adsorption section, and can cause power generation in the fuel cell section with the reformed gas.

[0023] Another characteristic configuration of the fuel cell system according to the present invention includes an adsorption section having an adsorbent capable of adsorbing the raw fuel gas upstream of the reforming section and a temperature adjustment section capable of adjusting the temperature of the adsorbent. In the standby process, the control device sets the amount of the raw fuel gas received by the reforming unit from the gas meter to zero, and while generating the reformed gas using the raw fuel gas desorbed from the adsorbent by adjusting the temperature of the adsorbent by the temperature adjustment unit, causes the fuel cell unit to generate power.

[0024] According to the above characteristic configuration, in the standby process, while setting the amount of the raw fuel gas received by the reforming unit from the gas meter to zero, the reforming unit can generate the reformed gas using the raw fuel gas desorbed from the adsorption unit, and can cause the fuel cell unit to generate power using the reformed gas.

[0025] Yet another characteristic configuration of the fuel cell system according to the present invention is that it includes an anode exhaust gas pipe through which the anode exhaust gas supplied from the anode to the combustion unit flows.

[0026] According to the above characteristic configuration, there is a distance of at least the anode exhaust gas pipe from the anode to the combustion unit. Therefore, even if the reception of the raw fuel gas from the gas meter is stopped in the reforming unit of the fuel cell system, it is difficult for a backflow of air or the like from the combustion unit side to the anode to occur, and there is an advantage that the anode is less likely to deteriorate due to air.

[0027] Yet another characteristic configuration of the fuel cell system according to the present invention is that the control device determines the execution schedule of the leakage determination avoidance process including the standby process so that the standby process is performed a predetermined number of planned executions equal to or more than the set number at any point in time within a period of the same length as the future leakage determination period from that point.

[0028] According to the above characteristic configuration, the possibility that the gas meter determines that the state satisfying the non-leakage condition has occurred the set number of times during the leakage determination period increases.

[0029] Yet another characteristic configuration of the fuel cell system according to the present invention is that the control device monitors the operating state of a gas consumption device that consumes the raw fuel gas supplied via the gas meter. If the gas consumption device consumes the original fuel gas during the waiting process of the leakage determination avoidance process, the planned number of executions is increased.

[0030] According to the above characteristic configuration, even if the gas consumption device consumes the original fuel gas during the waiting process of the leakage determination avoidance process, by increasing the planned number of executions, the gas meter is more likely to determine that the state satisfying the non-leakage condition has occurred the set number of times during the leakage determination period.

[0031] Another characteristic configuration of the fuel cell system according to the present invention is that the control device monitors the operating state of a gas consumption device that consumes the original fuel gas supplied via the gas meter, If the gas consumption device consumes the original fuel gas during the waiting process of the leakage determination avoidance process, the length of the waiting period of the current waiting process or the waiting process to be performed in the future is extended.

[0032] According to the above characteristic configuration, even if the gas consumption device consumes the original fuel gas during the waiting process of the leakage determination avoidance process, by extending the length of the waiting period of the current waiting process or the waiting process to be performed in the future, the gas meter is more likely to determine that the state satisfying the non-leakage condition has occurred the set number of times during the leakage determination period.

[0033] Another characteristic configuration of the fuel cell system according to the present invention is that the control device preferentially performs the leakage determination avoidance process during a time period when the possibility of a gas consumption device that consumes the original fuel gas supplied via the same gas meter through which the reforming unit receives the supply of the original fuel gas performing a gas consumption operation is low.

[0034] According to the above characteristic configuration, since the possibility of a state being determined by the gas meter as satisfying the non-leakage condition occurring during the leakage determination avoidance process increases, the gas meter is more likely to determine that the state satisfying the non-leakage condition has occurred the set number of times during the leakage determination period.

[0035] Still another characteristic configuration of the fuel cell system according to the present invention is that while the control device is performing the standby process, the control device prevents a gas consumption device that consumes the raw fuel gas supplied via the same gas meter as the reforming unit receives the supply of the raw fuel gas from performing a gas consumption operation.

[0036] According to the above characteristic configuration, during the standby process, by preventing the use of gas in a gas consumption device that consumes the raw fuel gas supplied via the same gas meter as the reforming unit receives the supply of the raw fuel gas, the possibility of a state determined by the gas meter occurring when the non-leakage condition is satisfied is further increased.

Brief Description of the Drawings

[0037]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Embodiments for Carrying Out the Invention

[0038] Hereinafter, a fuel cell system S according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing the configuration of a fuel cell system S. The fuel cell system S includes a reforming unit 7, a fuel cell unit FC having an anode 8 and a cathode 9, a combustion unit 11, and a control device 22. In addition, the fuel cell system S of the present embodiment includes a raw fuel flow rate adjustment unit 5, an adsorption unit 6, an air flow rate adjustment unit 15, a heat exchanger 12, a water purifier 13, a water tank 14, and a water pump 16.

[0039] The reforming unit 7 steam-reforms a raw fuel gas containing hydrocarbons such as city gas supplied via the gas meter 1 through the raw fuel gas flow path L1b (L1) to generate a reformed gas containing hydrogen. The flow rate of the raw fuel gas received by the reforming unit 7 from the gas meter 1 per unit time is adjusted by the raw fuel flow rate adjustment unit 5. Then, the raw fuel gas whose flow rate has been adjusted by the raw fuel flow rate adjustment unit 5 is supplied to the reforming unit 7 via the adsorption unit 6.

[0040] Also, water stored in the water tank 14 is supplied to the reforming unit 7 via the water pump 16 and the water flow path L10, and the water is used for steam reforming of the raw fuel gas. Although not shown, a vaporizer for vaporizing the supplied water may be provided. The operation of the raw fuel flow rate adjustment unit 5 is controlled by the control device 22.

[0041] The adsorption unit 6 has an adsorbent 6a capable of adsorbing the raw fuel gas upstream of the reforming unit 7 and a temperature adjustment unit 6b capable of adjusting the temperature of the adsorbent 6a. The adsorbent 6a adsorbs the raw fuel gas when the temperature is low and desorbs the adsorbed raw fuel gas when the temperature is high. Therefore, the control device 22 can desorb the raw fuel gas from the adsorbent 6a by adjusting the temperature of the adsorbent 6a by the temperature adjustment unit 6b realized by using, for example, an electric heater. For example, the adsorbent 6a can be realized by using activated carbon or zeolite. In that case, the adsorbed raw fuel gas can be desorbed by setting the temperature of the adsorbent 6a to approximately 100°C to 200°C or higher. Note that, for example, silver zeolite or the like may be used as the adsorbent 6a, and it may be configured to also serve as a desulfurizing agent for removing sulfur components from city gas. The operation of the temperature adjustment unit 6b is controlled by the control device 22.

[0042] The reformate generated in the reforming section 7 is supplied to the fuel cell section FC via the reformed gas flow path L2. Also, oxygen gas (air) is supplied to the fuel cell section FC via the air flow path L4. The flow rate per unit time of the air (i.e., oxygen) supplied to the cathode 9 of the fuel cell section FC is adjusted by the air flow rate adjustment section 15. The fuel cell section FC includes an anode 8 to which the reformed gas generated in the reforming section 7 is supplied, a cathode 9 to which oxygen gas is supplied, and an electrolyte layer 10 provided therebetween. For example, the electrolyte layer 10 is configured using a solid oxide, and in that case, the fuel cell section FC has a solid oxide type power generation cell. The operation of the air flow rate adjustment section 15 is controlled by the control device 22.

[0043] The anode exhaust gas discharged from the anode 8 is supplied to the combustion section 11 via the anode exhaust gas flow path L3. The cathode exhaust gas discharged from the cathode 9 is supplied to the combustion section 11 via the cathode exhaust gas flow path L5. For example, the anode exhaust gas flow path L3 is an anode exhaust gas pipe through which the anode exhaust gas supplied from the anode 8 to the combustion section 11 flows. Also, for example, the cathode exhaust gas flow path L5 is a cathode exhaust gas pipe through which the cathode exhaust gas supplied from the cathode 9 to the combustion section 11 flows.

[0044] The combustion section 11 burns the combustion components contained in the anode exhaust gas discharged from the anode 8. Note that the cathode exhaust gas discharged from the cathode 9 is also supplied to the combustion section 11, and the oxygen contained in the cathode exhaust gas is used for combustion. Then, the combustion heat generated in the combustion section 11 is used for the steam reforming of the raw fuel gas by the reforming section 7. Also, when a vaporizer is provided, the combustion heat is supplied to the vaporizer and used for vaporizing water.

[0045] The exhaust combustion gas discharged from the combustion unit 11 is supplied to the heat exchanger 12 via the exhaust combustion gas flow path L6. Also, hot water flowing through the hot water circulation path L7 is supplied to the heat exchanger 12. Then, heat exchange between the exhaust combustion gas and the hot water is performed in the heat exchanger 12. In the present embodiment, by this heat exchange, the exhaust combustion gas is cooled and the hot water flowing through the hot water circulation path L7 is heated.

[0046] The hot water circulation path L7 circulates hot water between the hot water storage tank 17 and the heat exchanger 12. In the hot water storage tank 17, relatively low-temperature hot water is stored at its lower part, and relatively high-temperature hot water is stored at its upper part, that is, hot water is stored in a state where a temperature stratification is formed. Specifically, the hot water circulation path L7 includes an outgoing path for transferring hot water from the hot water storage tank 17 to the heat exchanger 12 and a return path for transferring hot water from the heat exchanger 12 to the hot water storage tank 17, and has a circulation pump 18 provided in the middle of the outgoing path.

[0047] With such a configuration, the hot water supplied from the lower part of the hot water storage tank 17 to the heat exchanger 12 via the outgoing path of the hot water circulation path L7 is heated in the heat exchanger 12, and the heated hot water is supplied to the upper part of the hot water storage tank 17 via the return path of the hot water circulation path L7. A temperature measurement unit 19 for measuring the temperature of the hot water transferred from the heat exchanger 12 to the hot water storage tank 17 is provided in the middle of the return path. In the present embodiment, the control device 22 controls the operation of the circulation pump 18 so that the temperature of the hot water flowing through the return path and flowing into the hot water storage tank 17 (the temperature of the hot water measured by the temperature measurement unit 19) reaches a predetermined hot water storage target temperature (for example, 65°C). In this way, hot water is stored, that is, heat is stored, in the hot water storage tank 17 in a state where a temperature stratification is formed.

[0048] At the lower part of the hot water storage tank 17, a water supply line L8a (L8) for supplying make-up water to the hot water storage tank 17 is connected, and at the upper part of the hot water storage tank 17, a hot water discharge line L9 for discharging the hot water stored in the hot water storage tank 17 is connected. A water supply line L8b (L8) is connected in the middle of the hot water discharge line L9, and make-up water can be mixed into the hot water discharged from the hot water storage tank 17. The amount of make-up water mixed into the hot water discharged from the hot water storage tank 17 is adjusted by a control valve 21 provided in the middle of the water supply line L8b. For example, the control device 22 controls the operation of the control valve 21 so that the temperature of the hot water after mixing measured by the temperature measurement unit 20 becomes a predetermined temperature (for example, 30°C). Then, the hot water after mixing is supplied to the user via the heat source device 4.

[0049] The heat source device 4 functions as a gas consumption device 2 that burns the raw fuel gas supplied via the gas meter 1 and heats the hot water with the combustion heat. For example, when the information reception unit 23 receives a request for 40°C hot water from the user, the control device 22 heats the hot water to 40°C with the heat source device 4 and then supplies it to the user.

[0050] The exhaust combustion gas discharged from the combustion unit 11 also contains water vapor. Therefore, when the exhaust combustion gas is cooled by the heat exchanger 12, the water vapor condenses. Then, the condensed water flows into the water recovery line L11. The recovered condensed water is supplied to the water tank 14 via the water purifier 13. The water purifier 13 is a device for removing impurities contained in the recovered condensed water. For example, the water purifier 13 is filled with an ion exchange resin or the like, and electrolytic ions (for example, salts and ammonia that are ionized and dissolved) contained in the recovered condensed water are exchanged with, for example, H + , OH - to relatively lower the concentration of electrolytes contained in the recovered condensed water (that is, to lower the electrical conductivity).

[0051] When the state satisfying the non-leakage condition indicating that the flow rate of the raw fuel gas is zero or small does not occur the set number of times (for example, 30 times) during the leakage determination period (for example, the past 30 days), the gas meter 1 is configured to activate an alarm or cut off the supply of the raw fuel gas. For example, when the state where the flow rate of the raw fuel gas is equal to or less than the first set determination amount continues for the first set determination period (for example, 2 minutes) or more, or when the integrated flow rate of the raw fuel gas in the second set determination period (for example, 2 minutes) is equal to or less than the second set determination amount, the gas meter 1 determines that the state satisfying the non-leakage condition has occurred.

[0052] In the configuration illustrated in FIG. 1, the raw fuel gas is supplied from the gas meter 1 to the reforming unit 7 of the fuel cell system S via the raw fuel gas flow path L1b (L1), and the raw fuel gas is supplied to the heat source device 4 of the fuel cell system S via the raw fuel gas flow path L1c (L1). Further, the raw fuel gas is also supplied from the gas meter 1 to the gas equipment 3 as the gas consumption device 2 such as a gas stove and a gas combustion type fan heater via the raw fuel gas flow path L1a (L1). Therefore, the gas meter 1 determines whether or not a state satisfying the non-leakage condition has occurred with respect to the consumption of the raw fuel gas in all of the reforming unit 7, the heat source device 4, and the gas equipment 3, for example. If the state satisfying such a non-leakage condition occurs the set number of times (for example, 30 times) during the leakage determination period (for example, the past 30 days), the gas meter 1 determines that there is no abnormality and resets the timing of the leakage determination period to zero.

[0053] The control device 22 of the fuel cell system S performs, at the setting timing, such that the gas meter 1 determines that the state satisfying the non-leakage condition has occurred the set number of times during the leakage determination period, at least for the amount of the raw fuel gas received by the reforming unit 7 from the gas meter 1, to be an amount for which the gas meter 1 determines that the non-leakage condition is satisfied. Specifically, within a predetermined processing target period having the same length as the leakage determination period, the control device 22 generates reformed gas with the amount of the raw fuel gas received by at least the reforming unit 7 from the gas meter 1 being an amount for which the gas meter 1 determines that the non-leakage condition is not satisfied while performing power generation in the fuel cell unit FC, and then shifts from the power generation state to a standby state where at least for the amount of the raw fuel gas received by the reforming unit 7 from the gas meter 1, it is an amount for which the gas meter 1 determines that the non-leakage condition is satisfied, and continues the standby process including a leakage determination avoidance process that continues for a predetermined standby period longer than the set determination period (for example, the above-described first set determination period, second set determination period, etc.) which is a period for the gas meter 1 to determine whether the non-leakage condition is satisfied, for the set number of times or more.

[0054] For example, in the standby process, the control device 22 sets the amount of the raw fuel gas received by the reforming unit 7 from the gas meter 1 to zero and stops the power generation in the fuel cell unit FC. And, for example, when the leakage determination period is 30 days, the control device 22 performs the leakage determination avoidance process including the standby process that continues for a standby period of, for example, 3 minutes which is longer than the 2-minute set determination period of the gas meter 1, for 31 times or more within the 30-day processing target period having the same length. That is, in this example, the standby period is set to be 1 minute longer than the above-described set determination period of the gas meter 1, and the number of times of performing the leakage determination avoidance process within the 30-day processing target period is set to be 1 time more than the above-described set number of times of the gas meter 1.

[0055] FIG. 2 is a diagram for explaining a processing target period for performing the leakage determination avoidance process a set number of times or more. As shown in the figure, at any point in time, the control device 22 determines an execution schedule of the leakage determination avoidance process including the standby process so that the standby process is performed a predetermined number of scheduled executions equal to or greater than the set number within a period of the same length as the future leakage determination period from that point in time. In the example shown in FIG. 2, the scheduled execution timings of 31 leakage determination avoidance processes from T1 to T31 are set.

[0056] The scheduled execution timing of the leakage determination avoidance process can be set as appropriate. For example, the control device 22 may prioritize the execution of the leakage determination avoidance process during a time period when the heat source device 4 as the gas consumption device 2 that consumes the raw fuel gas supplied via the same gas meter 1 as the reforming unit 7 receives the supply of the raw fuel gas has a low possibility of performing a gas consumption operation. In that case, the control device 22 stores the number of times of the raw fuel gas consumption operation in the heat source device 4 as the gas consumption device 2, and derives, for example, the frequency of the gas consumption operation every hour within a day. Then, the control device 22 prioritizes the execution of the leakage determination avoidance process during a time period when the frequency of the gas consumption operation within a day is low. For example, when the control device 22 determines that the time periods with a low frequency of the gas consumption operation within a day are 2:00 and 4:00, the leakage determination avoidance process is scheduled to be performed twice at 2:00 and 4:00 within a day. In this case, an execution schedule for performing 60 leakage determination avoidance processes in the next 30 days (720 hours) is set. Therefore, since the possibility that a state determined by the gas meter 1 occurs in which the non-leakage condition is satisfied during the execution of the leakage determination avoidance process increases, the possibility that the gas meter 1 determines that the state in which the non-leakage condition is satisfied has occurred a set number of times during the leakage determination period increases.

[0057] FIG. 3 is a diagram for explaining the leakage determination avoidance process. In the example shown in FIG. 3, the leakage determination avoidance process includes a pre-process, a standby process, and a post-process. The pre-process is performed between time Ta and time Tb, the standby process is performed between time Tb and time Tc, and the post-process is performed between time Tc and time Td. Note that the leakage determination avoidance process may include the pre-process and the standby process, or may include the standby process and the post-process.

[0058] Specifically, as leakage determination avoidance processing, the control device 22 performs pre-processing of stopping power generation in the fuel cell unit FC while the reforming unit 7 continues to receive the raw fuel gas from the gas meter 1 between time Ta and time Tb, performs standby processing after the pre-processing, and burns the anode exhaust gas discharged from the anode 8 in the combustion unit 11 while the pre-processing is being performed.

[0059] For example, in the pre-processing, the control device 22 controls the operation of a power conditioner (not shown) that extracts current from the fuel cell unit FC between time Ta and time Tb to not extract (generate) current from the fuel cell unit FC, that is, to stop power generation in the fuel cell unit FC. However, the control device 22 operates the raw fuel flow rate adjustment unit 5 to continuously supply the reforming unit 7 with the raw fuel gas, operates the air flow rate adjustment unit 15 to continuously supply the cathode 9 with air, and operates the water pump 16 to continuously supply the reforming unit 7 with water between time Ta and time Tb. Further, in the combustion unit 11, the combustion components contained in the anode exhaust gas discharged from the anode 8 are burned, and the combustion heat is supplied to the reforming unit 7. Therefore, between time Ta and time Tb, the reformed gas generated in the reforming unit 7 is burned in the combustion unit 11 without being used for power generation in the fuel cell unit FC.

[0060] In this way, since the anode exhaust gas (i.e., high-concentration raw fuel gas) discharged from the anode 8 is burned in the combustion unit 11 while the pre-processing is being performed, at the start point of the standby processing, the internal temperature of the hot module that houses, for example, the reforming unit 7, the fuel cell unit FC, and the combustion unit 11 becomes high due to the combustion heat released from the combustion unit 11. As a result, even if a temperature drop occurs in the reforming unit 7 during the subsequent standby processing, the temperature at the end point of the standby processing can be made high, and the deterioration effect on the fuel cell unit FC due to the temperature change can be suppressed.

[0061] Further, during the standby process, between time Tb and time Tc, the control device 22 stops the operation of the raw fuel flow rate adjustment unit 5, stops receiving the raw fuel gas from the gas meter 1 by the reforming unit 7, stops the operation of the air flow rate adjustment unit 15, and stops supplying air to the cathode 9. Then, between time Tb and time Tc, the control device 22 stops power generation, that is, does not draw current from the fuel cell unit FC. Incidentally, the control device 22 operates the water pump 16 to continuously supply water to the reforming unit 7 between time Tb and time Tc. Therefore, only water vapor is continuously supplied from the reforming unit 7 to the anode 8 between time Tb and time Tc. In this way, during the standby process, a mixed gas of water vapor and the fuel gas filled in the reforming unit 7 is supplied from the reforming unit 7 to the anode 8. Therefore, during the standby process, it is possible to prevent air or the like from entering the anode 8 from the outside and oxidizing and deteriorating the anode 8. Further, during the standby process or immediately after the restart of power generation, it is possible to prevent the S / C (steam / carbon ratio) of the gas supplied to the anode 8 from decreasing.

[0062] Further, as a leakage determination avoidance process, after the standby process, the control device 22 performs a post-treatment process between time Tc and time Td in which the reforming unit 7 resumes receiving the raw fuel gas from the gas meter 1 and generates reformed gas while stopping power generation in the fuel cell unit FC, and burns the anode exhaust gas discharged from the anode 8 in the combustion unit 11 while performing the post-treatment process.

[0063] For example, during the post-treatment process, between time Tc and time Td, the control device 22 does not draw current from the fuel cell unit FC. However, between time Tc and time Td, the control device 22 operates the raw fuel flow rate adjustment unit 5 to continuously supply the raw fuel gas to the reforming unit 7, operates the air flow rate adjustment unit 15 to continuously supply air to the cathode 9, and operates the water pump 16 to continuously supply water to the reforming unit 7. Further, in the combustion unit 11, the combustion components contained in the anode exhaust gas discharged from the anode 8 are burned, and the combustion heat is supplied to the reforming unit 7. Therefore, between time Tc and time Td, the reformed gas generated in the reforming unit 7 is burned in the combustion unit 11 without being used for power generation in the fuel cell unit FC.

[0064] Figure 4 is a flowchart for explaining the operation related to the leakage determination avoidance process of the control device 22. In step #10, the control device 22 determines whether it is the start timing of the leakage determination avoidance process. For example, the control device 22 determines whether the time Ta illustrated in FIG. 3 has arrived. And when it is the start timing of the leakage determination avoidance process, the control device 22 proceeds to step #11 and starts the leakage determination avoidance process. In the case of the example described with reference to FIG. 3, the control device 22 performs the preprocessing of the leakage determination avoidance process between time Ta and time Tb, and starts the standby process as the leakage determination avoidance process from time Tb. Then, while performing the standby process of the leakage determination avoidance process, the control device 22 monitors the operation of the heat source device 4 as the gas consumption device 2 (that is, the gas combustion operation).

[0065] Thereafter, in step #12, the control device 22 determines whether it is the end timing of the standby process of the leakage determination avoidance process. In the case of the example shown in FIG. 3, the control device 22 determines whether the time Tc has arrived. And when it is the end timing of the standby process, the control device 22 proceeds to step #13 and ends the standby process.

[0066] Next, in step #14, when it is the end timing of the leakage determination avoidance process, the control device 22 proceeds to step #15 and ends the leakage determination avoidance process. In the case of the example shown in FIG. 3, when the control device 22 determines that the time Td, which is the end timing of the post-processing of the leakage determination avoidance process, has arrived, it ends the post-processing, that is, ends the leakage determination avoidance process.

[0067] While performing the standby process of the leakage determination avoidance process, the control device 22 monitors whether there has been a gas consumption operation by the heat source device 4 as the gas consumption device 2. And when there has been a gas consumption operation by the heat source device 4 as the gas consumption device 2 during the standby process of the leakage determination avoidance process, that is, when the standby process fails, it can be presumed that the gas meter 1 does not determine that a non-leakage condition has occurred during the period of the standby process. Therefore, if the number of standby processes without a gas consumption operation by the heat source device 4, that is, the number of successful standby processes, is less than a set number such as 30 times within a processing target period such as the past 30 days, it can be presumed that the gas meter 1 has had a non-leakage condition occur a set number of times such as 30 times during the leakage determination period such as the past 30 days. In that case, the control device 22 may notify the user by voice information or character information that there is a high possibility of an alarm operation by the gas meter 1 or a shut-off of the supply of the source fuel gas using a remote control device or the like that displays the operating state of the fuel cell system S or the like.

[0068] While performing the standby process of the leakage determination avoidance process, if there has been a gas consumption operation by the heat source device 4 as the gas consumption device 2, the control device 22 may operate to set an additional standby process. That is, the control device 22 may operate to reset the execution schedule of the leakage determination avoidance process. Note that when there is a gas consumption device 2 whose operating state can be monitored separately from the heat source device 4, the control device 22 may also operate to reset the execution schedule of the leakage determination avoidance process including the monitoring result of the operating state of that gas consumption device 2.

[0069] Specifically, the control device 22 can reset the execution schedule of the leakage determination avoidance process by setting an additional standby process at the timing of extending the currently executed standby process or the standby process to be performed in the future. For example, the control device 22 monitors the operating state of at least some of the gas consumption devices 2 that consume the raw fuel gas supplied via the gas meter 1. When the gas consumption device 2 consumes the raw fuel gas during the standby process of the leakage determination avoidance process, the control device 22 extends the length of the standby period of the currently ongoing standby process or the standby process to be performed in the future. In the case of the example shown in FIG. 3, the control device 22 resets the stop timing of the standby process to a time Tc + α later than the time Tc instead of the time Tc. That is, the control device 22 resets the execution schedule of the leakage determination avoidance process so as to extend the currently executed standby process by a period α. In that case, the end timing of the post-stop process is also reset to the time Td + α. For example, in the above-described example, the case where the standby period is set to 3 minutes has been described. However, the extended length “α” of the standby period can be set to, for example, 2 minutes, and as a result, the total standby period for one time becomes 5 minutes.

[0070] In addition, when the gas consumption operation by the heat source device 4 as the gas consumption device 2 continues, if the extension of the standby process is repeated many times, the length of one standby period may become long. In that case, an upper limit such as 20 minutes may be provided for the length of one standby period. And when the length of one standby period reaches, for example, 20 minutes, the control device 22 may forcibly terminate the standby process. Further, when the control device 22 forcibly terminates the standby process, the control device 22 may extend the length of the standby period of the next standby process to be performed, or add a new leakage determination avoidance process within the currently set processing target period as described later.

[0071] Alternatively, the control device 22 can reset the execution schedule of the leakage determination avoidance process by setting to add a new leakage determination avoidance process within the currently set processing target period. For example, the control device 22 monitors the operating state of the gas consumption device 2 that consumes the raw fuel gas supplied via the gas meter 1, and if the gas consumption device 2 consumes the raw fuel gas during the standby process of the leakage determination avoidance process, the planned number of executions of the leakage determination avoidance process is increased. In the case of the example shown in FIG. 2, the control device 22 sets a plan to newly add one leakage determination avoidance process between the current time and the planned execution timing of the leakage determination avoidance process at T31. For example, if the current time is 5:00 am and the planned execution timing of the next leakage determination avoidance process originally planned is 2:00 am the next day, a plan to newly execute one leakage determination avoidance process, for example, at 11:00 pm on the same day, is added during that period.

[0072] As described above, the control device 22 performs the leakage determination avoidance process including the standby process of stopping the reception of the raw fuel gas from the gas meter 1 for the above standby period for a set number of times or more within a predetermined processing target period having the same length as the leakage determination period. As a result, the possibility that the gas meter 1 determines that the state of satisfying the non-leakage condition has occurred a set number of times during the leakage determination period is increased. Further, in the reforming unit 7 of the fuel cell system S, it is only necessary to stop the reception of the raw fuel gas from the gas meter 1 for at least the above set determination period. This set determination period is a value set for each gas meter 1, but if this set determination period is short, the standby period during which the reforming unit 7 of the fuel cell system S stops receiving the raw fuel gas from the gas meter 1 can also be short. Therefore, it is not necessary to stop the fuel cell system S for one day as in the conventional case.

[0073] <Another Embodiment> <1> In the above embodiment, the configuration of the fuel cell system S has been specifically described, but the configuration can be changed as appropriate.

[0074] <2> In the above-described embodiment, while the control device 22 is performing the standby process, the temperature adjustment unit 6b may adjust the temperature of the adsorbent 6a to desorb the raw fuel gas from the adsorbent 6a.

[0075] For example, in the standby process, the control device 22 sets the amount of the raw fuel gas received by the reforming unit 7 from the gas meter 1 to zero, that is, in a state where the gas meter 1 determines that the non-leakage condition is satisfied, and stops the power generation in the fuel cell unit FC. While doing so, the temperature adjustment unit 6b may adjust the temperature of the adsorbent 6a to desorb the raw fuel gas from the adsorbent 6a. In this case, the raw fuel gas desorbed from the adsorbent 6a during the standby process diffuses to the anode 8 through the reforming unit 7. Therefore, during the standby process of the leakage determination avoidance process, the intrusion of air or the like from the outside into the anode 8 or the like is suppressed.

[0076] Alternatively, in the standby process, the control device 22 may perform power generation in the fuel cell unit FC while generating reformed gas in the reforming unit 7 using the raw fuel gas that has been desorbed from the adsorbent 6a by temperature adjustment of the adsorbent 6a by the temperature adjustment unit 6b. FIG. 5 is a diagram for explaining the leakage determination avoidance process of another embodiment. In the example shown in FIG. 5, the leakage determination avoidance process includes a standby process performed between time Tb and time Tc. In this case, in the standby process, the control device 22 sets the amount of raw fuel gas received by the reforming unit 7 from the gas meter 1 to zero, that is, sets it to a state where the gas meter 1 determines that the non-leakage condition is satisfied, and performs temperature adjustment of the adsorbent 6a by the temperature adjustment unit 6b to desorb the raw fuel gas from the adsorbent 6a, and while generating reformed gas in the reforming unit 7 using the desorbed raw fuel gas, causes power generation to be performed in the fuel cell unit FC. Although the raw fuel gas desorbed from the adsorbent 6a diffuses and is supplied to the reforming unit 7, if the amount of raw fuel gas received by the reforming unit 7 from the gas meter 1 is set to zero, the gas meter 1 determines that the non-leakage condition is satisfied. Then, since the reforming unit 7 can generate reformed gas using the raw fuel gas desorbed from the adsorbent 6a, the control device 22 can extract (generate power) the current from the fuel cell unit FC. However, the continuous power generation performed in this standby process is the continuous power generation in an idling state in which the generated power of the fuel cell unit FC is supplied only to devices such as the water pump 16, the circulation pump 18, the raw fuel flow rate adjustment unit 5, the air flow rate adjustment unit 15, the control device 22, the temperature adjustment unit 6b, and a power conditioner (not shown) that are necessary for operating the fuel cell unit FC.

[0077] In the example shown in FIG. 5, the details of the operation performed between time Ta and time Tb and between time Tc and time Td can be set as appropriate. For example, the operation performed between time Ta and time Tb may be the same as or different from the operation performed before time Ta. Similarly, the operation performed between time Tc and time Td may be the same as or different from the operation performed after time Td.

[0078] <3> In the above embodiment, an example in which the control device 22 sets the amount of the raw fuel gas received by the reforming unit 7 from the gas meter 1 to zero in the standby process (that is, an example in which the amount is set to the amount at which the gas meter 1 is determined to satisfy the non-leakage condition) was described. However, if the gas meter 1 is determined to satisfy the non-leakage condition, the reforming unit 7 may receive the raw fuel gas from the gas meter 1. Then, in the standby process, the control device 22 may cause the fuel cell unit FC to generate power while the reforming unit 7 receives the raw fuel gas in an amount determined to satisfy the non-leakage condition from the gas meter 1 and generates the reformed gas.

[0079] FIG. 6 is a diagram for explaining the leakage determination avoidance process of another embodiment. In the example shown in FIG. 6, the leakage determination avoidance process includes a standby process performed between time Tb and time Tc. In this case, in the standby process, the control device 22 causes the reforming unit 7 to receive the raw fuel gas in an amount determined to satisfy the non-leakage condition from the gas meter 1. For example, if, as in the above-described example, the gas meter 1 is determined to satisfy the non-leakage condition when the state in which the flow rate of the raw fuel gas is equal to or less than the first set determination amount continues for a period equal to or longer than the first set determination period, the control device 22 controls the operation of the raw fuel flow rate adjustment unit 5 in this standby process to keep the flow rate of the raw fuel gas to the reforming unit 7 equal to or less than the first set determination amount, and may continue to receive the raw fuel gas from the gas meter 1 by the reforming unit 7. Alternatively, if the gas meter 1 is determined to be in a state where the non-leakage condition is satisfied when the integrated flow rate of the raw fuel gas in the second set determination period is equal to or less than the second set determination amount, etc., the control device 22 controls the operation of the raw fuel flow rate adjustment unit 5 in this standby process to keep the integrated flow rate of the raw fuel gas in the same period as the second set determination period equal to or less than the second set determination amount, and may continue to receive the raw fuel gas from the gas meter 1 by the reforming unit 7. And since the reforming unit 7 can generate the reformed gas using the raw fuel gas received from the gas meter 1, the control device 22 can take out (generate power) the current from the fuel cell unit FC. However, the continuous power generation performed in this standby process is the same continuous power generation in the idling state as described above.

[0080] Furthermore, in the standby process, the control device 22 may receive from the gas meter 1 an amount of raw fuel gas that is determined to satisfy the non-leakage condition by the reforming unit 7, and generate power in the fuel cell unit FC while generating reformed gas in the reforming unit 7 using the raw fuel gas that has been desorbed from the adsorbent 6a by adjusting the temperature of the adsorbent 6a by the temperature adjustment unit 6b.

[0081] Also in the example shown in FIG. 6, the details of the operation performed between time Ta and time Tb and between time Tc and time Td can be set as appropriate. For example, the operation performed between time Ta and time Tb may be the same as or different from the operation performed before time Ta. Similarly, the operation performed between time Tc and time Td may be the same as or different from the operation performed after time Td.

[0082] <4> In the above embodiment, an example in which the reforming unit 7 continues to receive water for steam reforming while performing the leakage determination avoidance process has been described. However, for example, the reforming unit 7 may stop receiving water for steam reforming while performing the standby process of the leakage determination avoidance process.

[0083] <5> In the above embodiment, an information reception unit 23 that receives gas meter information that can specify the above setting determination period (first setting determination period, first setting determination period), the above setting determination flow rate (first setting determination flow rate, second setting determination flow rate), the above leakage determination period, the number of settings, etc. regarding the gas meter 1 is provided, and the control device 22 may perform a leakage determination avoidance process based on the gas meter information received by the information reception unit 23.

[0084] FIG. 7 is a diagram showing a state in which the fuel cell system S and the server device 26 are connected via the information communication line 25. As shown in the figure, a gas meter 1 and a fuel cell system S as exemplified in FIG. 1 are installed in a facility 27 such as a residential house or a business office. The server device 26 stores gas meter information regarding the gas meter 1 installed in each of the plurality of facilities 27.

[0085] The server device 26 transmits, to each fuel cell system S, the gas meter information of the gas meter 1 installed in the same facility 27 as that fuel cell system S via the information communication line 25 to that fuel cell system S. The fuel cell system S stores the received gas meter information in the information storage unit 24. Then, when performing the leakage determination avoidance process, the control device 22 of the fuel cell system S refers to the gas meter information stored in the information storage unit 24 to determine the length of the processing target period, the length of the standby period, the planned number of times of performing the leakage determination avoidance process during that processing target period, the amount of the raw fuel gas received by the reforming unit 7 from the gas meter 1, and the like.

[0086] <6> In the above embodiment, numerical examples regarding the length of the processing target period, the length of the standby period, the planned number of times of performing the leakage determination avoidance process during that processing target period, the implementation schedule, and the like are described, but those values are described for illustrative purposes and can be changed as appropriate.

[0087] <7> In the above embodiment, the case where the heat source device 4 as the gas consumption device 2 is used for the hot water supply application for supplying hot water to the user is described. However, the heat source device 4 as the gas consumption device 2 may be, for example, a heat source device 4 for heating for heating a heat medium supplied to a floor heating device, a bathroom heating and drying device, and the like. When the heat source device 4 is used for such heating applications, even if the heat source device 4 temporarily stops the gas consumption operation and stops heating the heat medium, it is less likely that the users of the floor heating device or the bathroom heating and drying device can feel it. Therefore, while performing the above standby process, the control device 22 may prevent the heat source device 4 as the gas consumption device 2 that consumes the raw fuel gas supplied via the same gas meter 1 as that through which the reforming unit 7 receives the supply of the raw fuel gas from performing the gas consumption operation. Note that the control device 22 cannot block the gas consumption operations of all the gas consumption devices 2 that receive the supply of the raw fuel gas from the gas meter 1. For example, the control device 22 can block the gas consumption operation of the heat source device 4 included in the fuel cell system S, for example, but cannot block the gas consumption operation of the gas equipment 3 shown in FIG. 1.

[0088] In this way, during the standby process, by preventing the gas consumption in the gas consumption device 2 that consumes the raw fuel gas supplied via the same gas meter 1 as the reforming unit 7 receives the supply of the raw fuel gas, the possibility of generating a state determined by the gas meter 1 when the non-leakage condition is satisfied is further increased. As a result, the possibility that the control device 22 has to set the additional standby process as described above can be reduced.

[0089] <8> In addition, the configurations disclosed in the above embodiments (including other embodiments, the same hereinafter) can be applied in combination with the configurations disclosed in other embodiments as long as there is no contradiction. Further, the embodiments disclosed in this specification are examples, and the embodiments of the present invention are not limited thereto, and can be appropriately modified within the scope not departing from the object of the present invention.

Industrial Applicability

[0090] The present invention can be used in a fuel cell system that can appropriately generate a state determined by a gas meter when a non-leakage condition is satisfied without significantly impairing the merits of users.

Explanation of Reference Numerals

[0091] 1: Gas meter 2: Gas consumption device 3: Gas equipment (gas consumption device 2) 4: Heat source device (gas consumption device 2) 6: Adsorbing part 6a: Adsorbent 6b: Temperature adjusting part 7: Reforming part 8: Anode 9: Cathode 10: Electrolyte layer 11: Combustion part 22: Control device 23: Information receiving part FC: Fuel cell part S: Fuel cell system

Claims

1. A reforming unit that steam-reforms a raw fuel gas containing hydrocarbons supplied via a gas meter to generate a reformed gas containing hydrogen; a fuel cell unit having an anode to which the reformed gas generated in the reforming unit is supplied and a cathode to which oxygen gas is supplied; a combustion unit that burns combustion components contained in anode exhaust gas discharged from the anode; and a control device, wherein the combustion heat generated in the combustion unit is used for steam reforming by the reforming unit, The gas meter is configured to activate an alarm or shut off the supply of the raw fuel gas when a state satisfying a non-leakage condition indicating that the flow rate of the raw fuel gas is zero or low does not occur a set number of times during a leakage determination period. A fuel cell system, An adsorption unit having an adsorbent capable of adsorbing the raw fuel gas upstream of the reforming unit and a temperature adjustment unit capable of adjusting the temperature of the adsorbent, The control device shifts from a power generation state in which power generation is performed in the fuel cell unit while generating the reformed gas in an amount such that, for at least the amount of the raw fuel gas received by the reforming unit from the gas meter, the gas meter is determined not to satisfy the non-leakage condition, within a predetermined processing target period having the same length as the leakage determination period, to a standby state in which, for at least the amount of the raw fuel gas received by the reforming unit from the gas meter, the gas meter is determined to satisfy the non-leakage condition, and continues the standby state for a predetermined standby period longer than a set determination period that is a period for the gas meter to determine whether the non-leakage condition is satisfied, and performs the leakage determination avoidance process including the standby process a set number of times or more, The control device is a fuel cell system that, while performing the standby process, adjusts the temperature of the adsorbent by the temperature adjustment unit to desorb the raw fuel gas from the adsorbent.

2. A reforming unit that steam-reforms a raw fuel gas containing hydrocarbons supplied via a gas meter to generate a reformed gas containing hydrogen; a fuel cell unit having an anode to which the reformed gas generated in the reforming unit is supplied and a cathode to which oxygen gas is supplied; a combustion unit that burns combustion components contained in anode exhaust gas discharged from the anode; and a control device, wherein the combustion heat generated in the combustion unit is used for steam reforming by the reforming unit, The fuel cell system is configured such that when a state satisfying a non-leakage condition indicating that the flow rate of the raw fuel gas is zero or low does not occur the set number of times during a leakage determination period, an alarm is activated or the supply of the raw fuel gas is shut off. The fuel cell system includes an adsorption unit having an adsorbent capable of adsorbing the raw fuel gas upstream of the reforming unit and a temperature adjustment unit capable of adjusting the temperature of the adsorbent. During a predetermined processing target period having the same length as the leakage determination period, the control device shifts from a power generation state in which power generation is performed in the fuel cell unit while generating reformed gas with an amount of the raw fuel gas received by at least the reforming unit from the gas meter being set to an amount for which the gas meter determines that the non-leakage condition is not satisfied, to a standby state in which the amount of the raw fuel gas received by at least the reforming unit from the gas meter is set to an amount for which the gas meter determines that the non-leakage condition is satisfied, and continues the standby state for a predetermined standby period longer than a set determination period which is a period for the gas meter to determine whether the non-leakage condition is satisfied, and performs the leakage determination avoidance process including the standby process the set number of times or more. In the standby process, the control device adjusts the temperature of the adsorbent by the temperature adjustment unit and causes the fuel cell unit to generate power while generating reformed gas using the raw fuel gas desorbed from the adsorbent. According to claim 3, a fuel cell system includes a reforming unit that steam reforms a raw fuel gas containing hydrocarbons supplied via a gas meter to generate a reformed gas containing hydrogen, an anode to which the reformed gas generated by the reforming unit is supplied, a cathode to which oxygen gas is supplied, a combustion unit that burns combustion components contained in anode exhaust gas discharged from the anode, and a control device, wherein combustion heat generated in the combustion unit is used for steam reforming by the reforming unit. The fuel cell system is configured such that when a state satisfying a non-leakage condition indicating that the flow rate of the raw fuel gas is zero or low does not occur the set number of times during a leakage determination period, an alarm is activated or the supply of the raw fuel gas is shut off. The fuel cell system includes an adsorption unit having an adsorbent capable of adsorbing the raw fuel gas upstream of the reforming unit and a temperature adjustment unit capable of adjusting the temperature of the adsorbent. The control device shifts from a power generation state in which power generation is performed by the fuel cell unit while generating reformed gas with an amount of the raw fuel gas received by at least the reforming unit from the gas meter set to an amount for which the gas meter determines that the non-leakage condition is not satisfied within a predetermined processing target period having the same length as the leakage determination period, to a standby state in which the amount of the raw fuel gas received by at least the reforming unit from the gas meter is set to an amount for which the gas meter determines that the non-leakage condition is satisfied, and continues the standby state for a predetermined standby period longer than a set determination period which is a period for the gas meter to determine whether or not the non-leakage condition is satisfied, and performs a leakage determination avoidance process including the standby process more than the set number of times. In the standby process, the control device sets the amount of the raw fuel gas received by the reforming unit from the gas meter to zero, adjusts the temperature of the adsorbent by the temperature adjustment unit, and generates reformed gas using the raw fuel gas desorbed from the adsorbent while causing the fuel cell unit to perform power generation. **Claim 4**: A fuel cell system comprising: a reforming unit that steam-reforms a raw fuel gas containing hydrocarbons supplied via a gas meter to generate a reformed gas containing hydrogen; an anode to which the reformed gas generated by the reforming unit is supplied; a fuel cell unit having a cathode to which oxygen gas is supplied; and a combustion unit that burns combustion components contained in anode exhaust gas discharged from the anode, and a control device, wherein combustion heat generated by the combustion unit is used for steam reforming by the reforming unit. The fuel cell system is configured such that when a state in which the non-leakage condition indicating that the flow rate of the raw fuel gas is zero or low is not set a set number of times during the leakage determination period, the gas meter activates an alarm or shuts off the supply of the raw fuel gas. During a predetermined processing target period having the same length as the leakage determination period, the control device generates reformed gas with an amount such that, for at least the amount of the raw fuel gas received by the reforming unit from the gas meter, the gas meter determines that the non-leakage condition is not satisfied, while performing power generation in the fuel cell unit. Then, the control device shifts to a standby state with an amount such that, for at least the amount of the raw fuel gas received by the reforming unit from the gas meter, the gas meter determines that the non-leakage condition is satisfied, and continues the standby process for a predetermined standby period longer than the set determination period, which is the period for the gas meter to determine whether the non-leakage condition is satisfied, for the leakage determination avoidance process including the standby process. This is done more than the set number of times. At any point in time, the control device determines the implementation schedule of the leakage determination avoidance process including the standby process so that the standby process is performed a predetermined number of planned implementation times, which is more than the set number of times, within a period having the same length as the future leakage determination period from that point. The control device monitors the operating state of the gas consumption device that consumes the raw fuel gas supplied via the gas meter. If the gas consumption device consumes the raw fuel gas during the standby process of the leakage determination avoidance process, the fuel cell system increases the planned number of implementation times. **Claim 5**: A fuel cell system comprising a reforming unit that steam-reforms a raw fuel gas containing hydrocarbons supplied via a gas meter to generate a reformed gas containing hydrogen, a fuel cell unit having an anode to which the reformed gas generated by the reforming unit is supplied and a cathode to which oxygen gas is supplied, a combustion unit that burns combustion components contained in the anode exhaust gas discharged from the anode, and a control device, wherein the combustion heat generated in the combustion unit is used for steam reforming by the reforming unit. The fuel cell system is configured such that the gas meter alarms or shuts off the supply of the raw fuel gas when the state satisfying the non-leakage condition indicating that the flow rate of the raw fuel gas is zero or low does not occur the set number of times during the leakage determination period. The control device performs power generation in the fuel cell unit while generating reformed gas with an amount such that, within a predetermined processing target period having the same length as the leakage determination period, at least for the amount of the raw fuel gas received by the reforming unit from the gas meter, the gas meter determines that the non-leakage condition is not satisfied. Then, it shifts to a standby state with an amount such that, at least for the amount of the raw fuel gas received by the reforming unit from the gas meter, the gas meter determines that the non-leakage condition is satisfied. The control device includes a leakage determination avoidance process that includes a standby process of continuing this standby state for a predetermined standby period longer than a set determination period, which is a period for the gas meter to determine whether the non-leakage condition is satisfied, for the set number of times or more. At any point in time, the control device determines an implementation schedule of the leakage determination avoidance process including the standby process so that the standby process is performed the set number of times or more, which is a predetermined planned number of times, within a period having the same length as the future leakage determination period from that point. The control device monitors an operating state of a gas consumption device that consumes the raw fuel gas supplied via the gas meter. When the gas consumption device consumes the raw fuel gas during the standby process of the leakage determination avoidance process, the fuel cell system extends the length of the standby period of the currently ongoing standby process or the standby process to be performed in the future.

6. A fuel cell system comprising: a reforming unit that steam-reforms a raw fuel gas containing hydrocarbons supplied via a gas meter to generate a reformed gas containing hydrogen; a fuel cell unit having an anode to which the reformed gas generated by the reforming unit is supplied and a cathode to which oxygen gas is supplied; a combustion unit that burns a combustion component contained in the anode exhaust gas discharged from the anode; and a control device, wherein the combustion heat generated in the combustion unit is used for steam reforming by the reforming unit. The fuel cell system is configured such that when a state satisfying a non-leakage condition indicating that the flow rate of the raw fuel gas is zero or low does not occur the set number of times during the leakage determination period, the gas meter activates an alarm or shuts off the supply of the raw fuel gas. During a predetermined processing target period having the same length as the leakage determination period, the control device generates reformed gas in an amount such that the gas meter is determined not to satisfy the non-leakage condition with respect to at least the amount of the raw fuel gas received by the reforming unit from the gas meter, and performs power generation in the fuel cell unit. Then, the control device shifts from the power generation state to a standby state in which the gas meter is determined to satisfy the non-leakage condition with respect to at least the amount of the raw fuel gas received by the reforming unit from the gas meter, and continues the standby state for a predetermined standby period longer than a setting determination period which is a period for the gas meter to determine whether or not the non-leakage condition is satisfied. The control device performs the leakage determination avoidance process including the standby process a set number of times or more. The fuel cell system includes an information reception unit that receives gas meter information capable of specifying the setting determination period, the leakage determination period, and the set number of times of the gas meter. The control device performs the leakage determination avoidance process based on the gas meter information received by the information reception unit.

7. The control device according to any one of claims 1, 4, 5, and 6, wherein in the standby process, the control device sets the amount of the raw fuel gas received by the reforming unit from the gas meter to zero and stops power generation in the fuel cell unit.

8. As the leakage determination avoidance process, the control device performs a pre-process of stopping power generation in the fuel cell unit while continuously receiving the raw fuel gas from the gas meter by the reforming unit, performs the standby process after the pre-process, and burns the anode exhaust gas discharged from the anode in the combustion unit while performing the pre-process.

9. As the leakage determination avoidance process, the control device performs a post-process of stopping power generation in the fuel cell unit while the reforming unit receives the raw fuel gas from the gas meter and generates reformed gas after the standby process, and burns the anode exhaust gas discharged from the anode in the combustion unit while performing the post-process.

10. The fuel cell system according to any one of claims 1, 4, 5, 6, 7, 8, and 9, wherein the control device continues to receive water for steam reforming in the reforming unit while performing the leakage determination avoidance process.

11. The fuel cell system according to any one of claims 4 to 10, further comprising an adsorption unit having an adsorbent capable of adsorbing the raw fuel gas upstream of the reforming unit and a temperature adjustment unit capable of adjusting the temperature of the adsorbent. The fuel cell system according to any one of claims 4 to 10, wherein the control device performs temperature adjustment of the adsorbent by the temperature adjustment unit to desorb the raw fuel gas from the adsorbent while performing the standby process.

12. The fuel cell system according to any one of claims 2, 4, 5, and 6, wherein the control device, in the standby process, receives an amount of the raw fuel gas from the gas meter in the reforming unit that is determined to satisfy the non-leakage condition, generates reformed gas, and causes power generation in the fuel cell unit.

13. The fuel cell system according to any one of claims 4, 5, 6, and 12, further comprising an adsorption unit having an adsorbent capable of adsorbing the raw fuel gas upstream of the reforming unit and a temperature adjustment unit capable of adjusting the temperature of the adsorbent. The fuel cell system according to any one of claims 4, 5, 6, and 12, wherein the control device, in the standby process, performs temperature adjustment of the adsorbent by the temperature adjustment unit to desorb the raw fuel gas from the adsorbent, generates reformed gas using the desorbed raw fuel gas, and causes power generation in the fuel cell unit.

14. The fuel cell system according to any one of claims 4, 5, and 6, further comprising an adsorption unit having an adsorbent capable of adsorbing the raw fuel gas upstream of the reforming unit and a temperature adjustment unit capable of adjusting the temperature of the adsorbent. The fuel cell system according to any one of claims 4, 5, and 6, wherein the control device, in the standby process, sets the amount of the raw fuel gas received by the reforming unit from the gas meter to zero, performs temperature adjustment of the adsorbent by the temperature adjustment unit to desorb the raw fuel gas from the adsorbent, generates reformed gas using the desorbed raw fuel gas, and causes power generation in the fuel cell unit.

15. The fuel cell system according to any one of claims 1 to 14, wherein the fuel cell unit includes a solid oxide type power generation cell having the anode, the cathode, and an electrolyte layer using a solid oxide provided therebetween.

16. The fuel cell system according to any one of claims 1 to 15, comprising an anode exhaust gas pipe through which the anode exhaust gas supplied from the anode to the combustion unit flows.

17. At any point in time, the control device determines the execution schedule of the leakage determination avoidance process including the standby process so that the standby process is performed a predetermined number of planned executions equal to or greater than the set number within a period of the same length as the future leakage determination period from that point. The fuel cell system according to any one of claims 1 to 16.

18. The control device monitors the operating state of a gas consumption device that consumes the raw fuel gas supplied via the gas meter. When the gas consumption device consumes the raw fuel gas during the standby process of the leakage determination avoidance process, the fuel cell system according to claim 17, wherein the planned number of executions is increased.

19. The control device monitors the operating state of a gas consumption device that consumes the raw fuel gas supplied via the gas meter. When the gas consumption device consumes the raw fuel gas during the standby process of the leakage determination avoidance process, the fuel cell system according to claim 17 or 18, wherein the length of the standby period of the currently ongoing standby process or the future standby process is extended.

20. The control device preferentially performs the leakage determination avoidance process during a time period when a gas consumption device that consumes the raw fuel gas supplied via the same gas meter through which the reforming unit receives the supply of the raw fuel gas is less likely to perform a gas consumption operation. The fuel cell system according to any one of claims 1 to 19.

21. Comprising an information reception unit that receives gas meter information capable of specifying the set determination period, the leakage determination period, and the set number of times of the gas meter. The control device performs the leakage determination avoidance process based on the gas meter information received by the information reception unit. The fuel cell system according to any one of claims 1 to 20.

22. While the control device is performing the standby process, it prevents a gas consumption device that consumes the raw fuel gas supplied via the same gas meter through which the reforming unit receives the supply of the raw fuel gas from performing a gas consumption operation. The fuel cell system according to any one of claims 1 to 21.

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