JP7032964B2 - Power generation system - Google Patents

Description

The present invention is included in a reformer that reforms raw fuel gas to generate reformed fuel gas, a cell stack that generates power using the reformed fuel gas reformed by the reformer, and an exhaust gas. It relates to a power generation system equipped with a recovery water tank that collects and stores water.

As a power generation system, a system including a cell stack in which a plurality of fuel cell cells are stacked is known (see, for example, Patent Document 1). This power generation system is equipped with a steam generator that vaporizes the reformed water and a reformer that steam reforms the raw fuel gas with steam from the steam generator, and the cell stack is steam reformed by the reformer. Power is generated using the reformed fuel gas as the anode gas and the air as the cathode gas.

The reaction fuel gas (anodic off gas) discharged from the fuel electrode of the cell stack and the reaction air (cathode off gas) discharged from the air electrode are sent to the reformer burner, and a part of the raw fuel gas is also reformed. It is sent to the pawn burner, and a part of the reaction fuel gas and raw fuel gas is burned in the reformer burner, and this combustion heat is used to vaporize the reformed water in the steam generator and steam in the reformer. Reformation is performed.

Further, in connection with the cell stack, a hot water storage device for recovering heat generated in the system (for example, heat of exhaust gas) as hot water is provided. The hot water storage device is equipped with a hot water storage tank that stores hot water, and the combustion exhaust gas discharged from the reformer burner and the water from the hot water storage tank flow through the heat exchanger, and the exhaust heat is recovered by heat exchange in this heat exchanger. Then, the hot water warmed by this heat exchange is stored in the hot water storage tank.

Further, this heat exchange condenses the water in the combustion exhaust gas to generate condensed water, and the condensed water is recovered in the water recovery tank. The condensed water recovered in this water recovery tank is used as reforming water, and the condensed water in the water recovery tank is supplied to the steam generator as reforming water through the water supply flow path.

Japanese Unexamined Patent Publication No. 2017-174608

In such a power generation system, the condensed water in which the water in the combustion exhaust gas is condensed is collected in the water recovery tank. Therefore, when the temperature is high such as in summer, the condensed water collected in the water recovery tank contains various germs. It becomes easier to breed. When various germs propagate in this way, the propagated germs cause steam through the water supply channel when the condensed water is supplied to the steam generator through the water supply channel in order to use the condensed water in the water recovery tank as reforming water. Problems such as clogging of the water supply flow path due to germs that flow toward the generator and propagate may occur, and the condensed water (modified water) from the water recovery tank may not be supplied to the steam generator as desired. be.

An object of the present invention is to provide a power generation system capable of sterilizing condensed water in a water recovery tank and cooling water in a cooling water tank as required.

The power generation system according to claim 1 of the present invention includes a fuel gas supply flow path for supplying raw fuel gas, a reformer for steam reforming the raw material fuel gas supplied through the fuel gas supply flow path, and a reformer for steam reforming the raw material fuel gas. A cell stack that generates power using the reformed fuel gas reformed by the reformer as an anode gas and air as a cathode gas, a cooling water tank for accommodating cooling water for cooling the cell stack, and exhaust A water recovery tank for condensing and recovering the water contained in the gas and storing it is provided, and the condensed water collected in the water recovery tank is used as reforming water and sent to the reformer through a water supply flow path. It ’s a system,
A circulation flow path for returning the reformed water flowing through the water supply flow path to the cooling water tank is connected to the water supply flow path, and a circulation valve is provided in the circulation flow path. At the same time, a water circulation supply flow path for supplying the cooling water in the cooling water tank to the water recovery tank is provided between the cooling water tank and the water recovery tank, and the water supply flow path is provided. A water supply valve is provided on the downstream side of the connection site with the circulation flow path.
Further, the cooling water tank or the water recovery tank is provided with a heating means for heating and sterilizing the cooling water or the condensed water, and the reformer, the cooling water tank or the water. The recovery tank is provided with a reformer temperature detecting means, a cooling water temperature detecting means, or a reforming water temperature detecting means for detecting the temperature.
Further, in connection with the reformer temperature detecting means, the cooling water temperature detecting means, or the reforming water temperature detecting means, an abnormality determining means for determining the occurrence of an abnormality in the water supply valve is provided. Has been
During the power generation operation, the water supply valve is held in the open state, the circulation valve is held in the closed state, and the reformed water from the water recovery tank is supplied to the reformer through the water supply flow path. Further, when the sterilization treatment operation is performed, the heating means is operated, the water supply valve is held in the closed state, the circulation valve is held in the open state, and the water is heated in the cooling water tank or the water recovery tank. The cooling water or the reforming water is circulated through the water supply flow path, the circulation flow path, and the water circulation supply flow path, and the abnormality determination means is the reformer temperature detecting means and the cooling water temperature. It is characterized in that the occurrence of an abnormality in the water supply valve is determined based on the temperature change state of the detecting means or the temperature detecting means for reforming water.

Further, in the power generation system according to claim 2 of the present invention, an abnormality signal generation means for generating an abnormality signal is provided in connection with the abnormality determination means, and the abnormality determination means is the water supply valve. When the abnormality occurrence is determined, the abnormality signal generation means generates the abnormality signal based on the determination of the abnormality occurrence, and the sterilization processing operation is stopped based on the abnormality signal.

Further, in the power generation system according to claim 3 of the present invention, in connection with the abnormality determination means, a valve recovery operation signal generation for generating a valve recovery operation signal for opening and closing the water supply valve a plurality of times is further generated. A means is provided, and when the abnormality determination means determines the occurrence of an abnormality in the water supply valve, the abnormality signal generation means generates the abnormality signal based on the determination of the occurrence of the abnormality, and the abnormality signal is generated. The sterilization processing operation is stopped, the valve recovery operation signal generation means generates the valve recovery operation signal, and the water supply valve is opened and closed a plurality of times based on the valve recovery operation signal, and then the water supply valve is opened and closed a plurality of times. The sterilization treatment operation is restarted.

Further, in the power generation system according to claim 4 , when the abnormality determination means determines the occurrence of an abnormality in the water supply valve when the sterilization treatment operation is restarted, the abnormality occurrence during the sterilization treatment operation occurs. The abnormality signal generation means regenerates the abnormality signal based on the determination, and the sterilization processing operation is terminated based on the abnormality signal again.

Further, in the power generation system according to claim 5 of the present invention, a valve abnormality display means for notifying the occurrence of an abnormality in the water supply valve is further provided in connection with the abnormality determination means, and the abnormality is described. When the determination means determines the occurrence of an abnormality in the water supply valve, the abnormality signal generation means generates the abnormality signal based on the determination of the abnormality occurrence, and the valve abnormality display means based on the abnormality signal. It is characterized by operating.

Further, in the power generation system according to claim 6 of the present invention, an abnormality signal generation means for generating an abnormality signal is provided in connection with the abnormality determination means, and the abnormality determination means is the water supply valve. When the abnormality occurrence is determined, the abnormality signal generation means generates the abnormality signal based on the determination of the abnormality occurrence, the sterilization processing operation is terminated based on the abnormality signal, and then the power generation operation is restarted. It is characterized by that.

Further, in the power generation system according to claim 7 of the present invention, a valve abnormality display means for notifying the occurrence of an abnormality in the water supply valve is further provided in connection with the abnormality determination means, and the abnormality is described. When the determination means determines the occurrence of an abnormality in the water supply valve, the abnormality signal generation means generates the abnormality signal based on the determination of the abnormality occurrence, and the valve abnormality display means based on the abnormality signal. It is characterized by operating.

According to the power generation system according to claim 1 of the present invention, a circulation flow path is connected to a water supply flow path for supplying reforming water to the reformer, and a circulation valve is arranged in this circulation flow path. A water supply valve is provided on the downstream side of the connection portion of the water supply flow path with the circulation flow path, and a heating means for sterilizing the cooling water tank or the water recovery tank is provided . During the sterilization operation, the heating means is activated and the water supply valve is kept in the closed state and the circulation valve is kept in the open state, so that the condensed water (reformed water) in the water recovery tank is supplied with water. It is circulated through the flow path, the circulation flow path, and the water circulation supply flow path, and the condensed water can be circulated in this way for sterilization treatment.

Further, the reformer, the cooling water tank or the water recovery tank is provided with a temperature detecting means for a reformer for detecting the temperature, a temperature detecting means for cooling water or a temperature detecting means for reforming water, and a water supply valve. Since the abnormality determination means for determining the occurrence of the abnormality is provided, the temperature of the reformer temperature detecting means, the cooling water temperature detecting means, or the reforming water temperature detecting means at the time of performing this sterilization treatment operation is provided. It is possible to determine the occurrence of an abnormality in the water supply valve based on the change state.

For example, when a heating means is provided in the cooling water tank and a reformer temperature detecting means (or a cooling water temperature detecting means, a reforming water temperature detecting means) is used, the operation of the water supply valve is normal. Condensed water is circulated through the circulation channel and the water circulation feed channel, and this condensed water does not flow to the reformer. Therefore, the temperature detecting means for the reformer (or the temperature detection for cooling water) with the progress of the sterilization process. Means, temperature detecting means for reforming water) will increase the detection temperature. On the other hand, if the above-mentioned malfunction occurs in the water supply valve, a part or all of the condensed water circulated through the circulation flow path and the water circulation supply flow path will flow to the reformer, and therefore, The detection temperature of the temperature detecting means for the reformer hardly rises even with the progress of the sterilization treatment (or the detection temperature of the temperature detecting means for cooling water rises significantly with the progress of the sterilization treatment, and the reforming also with the progress of the sterilization treatment. The detection temperature of the water temperature detecting means hardly rises).

Further, for example, when a heating means is provided in the water recovery tank and a reformer temperature detecting means (or a cooling water temperature detecting means, a reforming water temperature detecting means) is used, the operation of the water supply valve is normal. And, as described above, the condensed water is circulated through the circulation flow path and the water circulation feed flow path, and therefore, with the operation time of the sterilization treatment, the temperature detecting means for the reformer (or the temperature detecting means for cooling water, for the reforming water). The detection temperature of the temperature detecting means) rises. On the other hand, if the above-mentioned malfunction occurs in the water supply valve, a part or all of the condensed water circulated through the circulation flow path and the water circulation supply flow path will flow to the reformer, and therefore, The detection temperature of the temperature detecting means for the reformer hardly rises even with the progress of the sterilization treatment (or the detection temperature of the temperature detecting means for cooling water hardly rises with the progress of the sterilization treatment, for the reformed water with the progress of the sterilization treatment. The detection temperature of the temperature detecting means rises significantly).

For this reason, the water supply valve is used based on the temperature change state of the detection temperature of the temperature detecting means for the reformer (or the temperature detecting means for cooling water, the temperature detecting means for reforming water) when performing the sterilization treatment operation. It is possible to detect the occurrence of abnormalities.

Further, according to the power generation system according to claim 2 , when the abnormality determination means determines the occurrence of an abnormality, the abnormality signal generation means generates an abnormality signal based on the determination of the occurrence of the abnormality, and this abnormality signal is generated. Since the sterilization treatment operation is stopped based on the above, it is possible to prevent a large amount of condensed water in the water recovery tank from flowing to the reformer.

Further, according to the power generation system according to claim 3 of the present invention, a valve recovery operation signal generation means for generating a valve recovery operation signal for opening and closing the water supply valve a plurality of times is further provided to generate an abnormal signal. When the means generate an abnormal signal, the sterilization processing operation is stopped based on this abnormal signal, the valve recovery operation signal generation means generates a valve recovery operation signal, and the water supply valve is generated based on this valve recovery operation signal. Since the water supply opening / closing operation (so-called recovery operation) is performed multiple times, for example, when dust or the like is clogged and a temporary closing failure occurs, the water supply valve is normally closed by this multiple opening / closing operation. , The sterilization treatment operation can be performed by recovering the closing failure.

Further, according to the power generation system according to claim 4 , when the abnormality determination means determines the occurrence of an abnormality in the water supply valve when the sterilization processing operation is restarted, the abnormality signal generation means generates an abnormality signal again. Therefore, if the water supply valve does not recover even after multiple opening and closing operations (recovery operation), the sterilization operation is terminated, which prevents a large amount of condensed water in the water recovery tank from flowing to the reformer. be able to.

Further, according to the power generation system according to claim 5 of the present invention, a valve abnormality display means for notifying the occurrence of an abnormality of the water supply valve is further provided, and when the abnormality signal generation means generates an abnormality signal, this abnormality is generated. Since the valve abnormality display means operates based on the signal, it is possible to notify the malfunction of the water supply valve (for example, the occurrence of a failure).

Further, according to the power generation system according to claim 6 , the abnormality determining means determines the occurrence of an abnormality in the water supply valve, and the abnormality signal generating means generates an abnormality signal based on the determination of the occurrence of the abnormality. Then, the sterilization processing operation ends based on this abnormal signal. In such a case, even if the water supply valve malfunctions, the condensed water (modified water) in the water recovery tank can be supplied to the reformer, so that the power generation operation can be performed. Therefore, by ending the sterilization treatment operation and restarting the power generation operation, it is possible to suppress a decrease in the operating efficiency of the power generation system.

Further, according to the power generation system according to claim 7 of the present invention, in connection with this abnormality determination means, a valve abnormality display means for notifying the occurrence of an abnormality in the water supply valve is further provided, and an abnormality signal is generated. Since the valve abnormality display means is operated based on the abnormality signal generated by the means, it is possible to notify that the water supply valve has an abnormality even during the power generation operation in the temporary state, whereby the water supply valve can be notified. Inspection and repair can be urged.

The whole view which shows the 1st Embodiment of the power generation system according to this invention simply. The explanatory view which shows the state of the sterilization processing operation in the power generation system of FIG. The block diagram which shows the control system of the power generation system of FIG. 1 simply. The figure for demonstrating the temperature change state of a reformer, the cooling water and the reforming water in the power generation system of FIG. 1, and the temperature change state of a reformer when a malfunction occurs in a water supply valve. The flowchart which shows the flow of an example of the control operation of the sterilization processing operation in the power generation system of FIG. The flowchart which shows the flow of another example of the control operation of the sterilization processing operation in the power generation system of FIG. The figure for demonstrating the temperature change state of the reformer, the cooling water and the reforming water in the power generation system of FIG. 1, and the temperature change state of the cooling water and the reforming water when a malfunction occurs in a water supply valve. The flowchart which shows the flow of the control operation of the sterilization processing operation at the time of detecting the temperature of the cooling water in the power generation system of FIG. The flowchart which shows the flow of the control operation of the sterilization processing operation at the time of detecting the temperature of reforming water in the power generation system of FIG. The block diagram which simply shows the control system of the 2nd Embodiment of the power generation system according to this invention. The flowchart which shows an example of the flow of the control operation of the sterilization processing operation in the power generation system of FIG.

Hereinafter, the first embodiment of the power generation system according to the present invention will be described with reference to the accompanying drawings. The illustrated power generation system includes a cell stack 2 that generates power by a fuel cell reaction, and a reformer 4 for steam reforming raw fuel gas. The cell stack 2 is configured by stacking fuel cell cells, and as the fuel cell, various types such as a solid polymer type and a solid oxide type can be used.

The cell stack 2 includes a fuel pole 6 and an air pole 8, and the fuel pole 6 side is connected to the reformer 4 through the reformed fuel gas supply flow path 10. The reformer 4 shown in the figure includes a steam generating unit 12 for vaporizing the reformed water and a reforming unit 14 filled with a reforming catalyst, and a carbon monoxide modifier 16 (on the downstream side of the reforming unit 14). A CO reformer) and a carbon monoxide remover 18 (CO remover) are arranged. Further, a desulfurization device 20 is arranged on the upstream side of the water vapor generation unit 12, and the desulfurization device 20 is connected to a raw fuel gas supply source 24 (for example, a fuel tank, a buried pipe, etc.) via a fuel gas supply flow path 22. Has been done. In this embodiment, the steam generating section 12 and the reforming section 14 of the reformer 4 are separately configured, but the steam generating section 12 and the reforming section 14 are integrally configured to form steam. The steam generated in the generating unit 12 and the raw fuel gas may be directly supplied to the reforming unit 14.

With this configuration, the raw fuel gas (for example, city gas) from the raw material fuel gas supply source 24 is sent to the desulfurizer 20 through the fuel gas supply flow path 22, and the raw material fuel in the desulfurizer 20 is supplied. The sulfur component contained in the gas is removed, and the raw fuel gas from which the sulfur component has been removed is sent to the steam generating section 12 of the reformer 4, and the reforming water is supplied to this steam generating section as described later. It is supplied to 12. In the steam generating section 12, the reformed water is vaporized, the raw fuel gas is mixed with the vaporized steam, and the mixed fuel gas is sent to the reforming section 14. In the reforming unit 14, steam reforming of the raw material and fuel gas is performed by the reforming catalyst. The steam-reformed reformed fuel gas is sent to the carbon monoxide metabolizer 16, where the carbon monoxide in the reformed fuel gas reacts with steam and is converted into carbon dioxide. Then, it is sent to the carbon monoxide remover 18, where the carbon monoxide remaining in the reformed fuel gas reacts with oxygen and is converted into carbon dioxide in this way. The reformed fuel gas from which carbon monoxide has been removed is supplied as an anode gas to the fuel electrode 6 side of the cell stack 2 through the reformed fuel gas supply flow path 10.

A reformer burner 28 is provided in the steam generating unit 12 and the reforming unit 14 of the reformer 4, and the combustion heat of the reformer burner 28 is used to vaporize the reformed water in the steam generating unit 12 and to vaporize the reformed water. Steam reforming of the raw material and fuel gas in the reforming unit 14 is performed. Further, a fuel supply pump 30 for supplying raw fuel gas is provided in the fuel gas supply flow path 22, and a fuel supply valve 32 is provided in the reformed fuel gas supply flow path 10.

Further, the air electrode 8 side of the cell stack 2 is connected to the air filter 35 via the air supply flow path 34, and the air blower 36 and the first heat exchanger 38 are arranged in the air supply flow path 34. .. Therefore, the air flowing in through the air filter 35 passes through the air supply flow path 34 and is heated by heat exchange in the first heat exchanger 38 as described later, and the heated air is supplied as a cathode gas. It is supplied to the air electrode 8 side of the cell stack 2 through the flow path 34. An air supply valve 40 is provided in the air supply flow path 34.

The discharge side of the fuel electrode 6 of the cell stack 2 is connected to the reformer burner 28 via the reaction fuel gas supply flow path 40 (anode off gas supply flow path). Further, a combustion air supply flow path 42 for supplying combustion air is connected to the reformer burner 28, and a combustion air blower 44 is arranged in the combustion air supply flow path 42. Further, a branched fuel gas flow path 46 branched from the fuel gas supply flow path 22 is connected to the reformer burner 28.

With this configuration, in the reformer burner 28, the raw fuel gas supplied through the branched fuel gas flow path 46 and the reactive fuel gas supplied through the reactive fuel gas supply channel 40 (unreacted fuel). (Contains gas) is burned by the combustion air supplied through the combustion air supply flow path 42, and the steam generating section 12 and the reforming section 14 of the reformer 4 are heated by using the combustion heat. To.

The combustion exhaust gas from the reformer burner 28 is discharged into the atmosphere through the exhaust gas discharge flow path 46, and the reaction air from the air electrode 8 side of the cell stack 2 is discharged into the atmosphere through the air discharge flow path 48. The heat of the combustion exhaust gas and the reaction air thus discharged is recovered as hot water by the hot water storage device 50. A discharge side fuel valve 64 is disposed on the discharge side of the fuel pole 6 of the cell stack 2, and a discharge side air valve 66 is disposed on the discharge side of the air pole 8.

The illustrated hot water storage device 50 includes a hot water storage tank 52 for storing hot water and a heat recovery circulation flow path 54, one end side of the heat recovery circulation flow path 54 is connected to the bottom of the hot water storage tank 52, and the other end side is the hot water storage tank 52. It is connected to the upper end of. The heat recovery circulation flow path 54 includes a circulation pump 56 for circulating water in the hot water storage tank 52 through the heat recovery circulation flow path 54, a combined heat exchanger 58, a second heat exchanger 60, and a surplus power heater 62. It is arranged.

With this configuration, the water from the hot water storage tank 52 is circulated through the heat recovery circulation flow path 54, and when the water is circulated in this way, the combustion exhaust flows through the exhaust gas discharge flow path 46 in the combined heat exchanger 58. It is heated by exchanging heat with the reaction air flowing through the gas and the air discharge flow path 48, and is heated by exchanging heat with the cooling water for cooling the cell stack 2 in the first heat exchanger 60. Further, when the generated power is surplus, it is heated by the residual heat power heater 62, and the hot water thus heated is stored in the hot water storage tank 52.

A heat recovery circulation valve 68 is arranged in the heat recovery circulation flow path 54. Further, a water supply flow path 80 is connected to the bottom of the hot water storage tank 52, and the water supply flow path 80 is connected to, for example, a water pipe (not shown), for example, tap water is supplied to the hot water storage tank 52. .. Further, a hot water flow path 82 is connected to the upper end of the hot water storage tank 52, and hot water is discharged through the hot water flow path 82. A water replenishment valve 84 for replenishing water is provided in the water replenishment flow path 80.

The cell stack 2 employs a cooling water circulation structure 70 that circulates cooling water for cooling the cell stack 2. The illustrated cooling water circulation structure 70 includes a cooling water circulation flow path 74 provided through a cooling unit 72 of the cell stack 2, and a cooling water tank 76 for accommodating cooling water, and a cooling water pump 78 is provided in the cooling water circulation flow path 74. It is arranged. Since it is configured in this way, the cooling water from the cooling water tank 76 flows to the cooling unit 72 of the cell stack 2 through the cooling water circulation flow path 74, and cools the cell stack 2 when flowing through the cooling unit 72. The cooling water after cooling flows through the cooling water circulation flow path 74, is cooled by heat exchange with the air flowing through the air supply flow path 34 in the second heat exchanger 60, and then is returned to the cooling water tank 76.

Further, the cooling water tank 76 is provided with a heat dissipation circulation flow path 80, and a heat dissipation circulation pump 82 is provided in the heat dissipation circulation flow path 80. Therefore, the cooling water in the cooling water tank 76 is circulated through the heat dissipation circulation flow path 80, and while flowing through the first heat exchanger 38, heat is exchanged with the air flowing through the air supply flow path 34, and heat is dissipated by heat exchange. The cooled cooling water is returned to the cooling water tank 76. A water replenishment flow path 84 is connected to the cooling water tank 76, and a water replenishment valve 86 is arranged in the water replenishment flow path 84.

In this embodiment, the water contained in the combustion exhaust gas and the water contained in the reaction air are condensed by heat exchange in the composite heat exchanger 58, and the condensed water is recovered in the water recovery tank 88. The composite heat exchanger 58 and the water recovery tank 88 are connected via a water recovery flow path 90, and the condensed water condensed by heat exchange in the composite heat exchanger 58 is passed through the water recovery flow path 90 to the water recovery tank. Collected at 88. In this form, both the moisture contained in the combustion exhaust gas and the moisture contained in the reaction air are condensed and recovered, but the present invention is not limited to such a configuration and the moisture contained in the combustion exhaust gas is not limited to this. Only may be condensed and recovered.

The condensed water recovered in the water recovery tank 88 is configured to be used as reformed water. That is, the water recovery tank 88 and the steam generating unit 12 of the reformer 4 are connected via a water supply flow path 90, and an ion exchange unit 92 and a water supply pump having an ion exchange resin built in the water supply flow path 90. 94 is arranged. With this configuration, the condensed water in the water recovery tank 88 is supplied as reforming water through the water supply flow path 90, is ion-exchanged by the ion exchange unit 92, and then is supplied to the steam generator 12. Will be done. In this power generation system, the power generation output from the cell stack 2 is converted from direct current to alternating current in the inverter 106 and then output through the power generation output line 108.

In this power generation system, the condensed water recovered in the water recovery tank 88 is further configured as follows so as to be sterilized. In this embodiment, a sterilization treatment heater 96 (which constitutes a heating means for sterilization treatment) is arranged in the cooling water tank 76, and the cooling water in the cooling water tank 76 is heated by the sterilization treatment heater 96. Further, the circulation flow path 98 is connected to the water supply flow path 90 (specifically, a portion downstream of the water supply pump 94), and the other end side of the circulation flow path 98 is connected to the cooling water tank 76. A circulation valve 100 is arranged in the circulation flow path 98. Further, the cooling water tank 76 and the water recovery tank 88 are connected to the water circulation supply flow path via 102. Furthermore, the water supply valve 104 is arranged in the water supply flow path (specifically, on the downstream side of the connection portion with the circulation flow path 98).

With this configuration, when power is generated by the cell stack 2, the water supply valve 104 is held in the open state and the circulation valve 100 is held in the closed state. When the water supply pump 94 operates in this state, the condensed water (reformed water) in the water recovery tank 88 is supplied to the steam generating section 12 of the reformer 4 through the water supply flow path 90, and the water supply flow path. The condensed water supplied through 90 can be used as reforming water to steam reform the raw fuel gas. At this time, since the circulation valve 100 is held in the closed state, the condensed water flowing through the water supply flow path 90 does not flow into the cooling water tank 76 through the circulation flow path 98.

Further, when the sterilization treatment is performed as described later, as shown in FIG. 2, the water supply valve 104 is held in the closed state and the circulation valve 100 is held in the open state. When the water supply pump 94 operates in such a state, the condensed water in the water recovery tank 88 is supplied to the cooling water tank 76 through the water supply flow path 90 and the circulation flow path 98, and further, the water circulation supply flow path. It is supplied to the water recovery tank 88 through 102, and is circulated through the water supply flow path 90, the circulation flow path 98, the cooling water tank 76, and the water circulation supply flow path 102.

In the power generation system having this sterilization treatment function, when the water supply valve 104 malfunctions, the condensed water from the water recovery tank 88 flows to the reformer 4 (in this case, the steam generator 110), and the reformer There is a possibility that trouble may occur in 4 (for example, the reforming catalyst of the reforming unit 14). Therefore, in this embodiment, the water supply valve 104 is configured as follows so as to be able to detect a malfunction.

More specifically, in this embodiment, the steam generating unit 12 of the reformer 4 is provided with a temperature detecting means 110 (for example, composed of a temperature sensor). The temperature detecting means 110 functions as a temperature detecting means for the reformer, detects the temperature of the steam generating unit 12 of the reformer 4, and malfunctions the water supply valve 104 based on the temperature change state of the detected temperature. Detects the presence or absence. Even if the temperature detecting means is arranged in the reforming unit 14 of the reformer 4, the presence or absence of malfunction of the water supply valve 104 can be detected in the same manner.

The detection by the temperature detecting means 110 is performed by the control system shown in FIG. With reference to FIG. 3, the power generation system includes a controller 112 (consisting of, for example, a microprocessor) that controls the entire system, and the controller 112 is an operation control means 114 for controlling the operation of the system. The operation control means 114 includes various valve means 126 (water supply valve 104, circulation valve 100, etc.) including the temperature calculation means 116, the temperature difference calculation means 118, the temperature difference comparison means 120, the abnormality determination means 122, and the abnormality signal generation means 124. ), Various pump means 128 (fuel supply pump 30, water supply pump 94, etc.) and various blowers 130 (air blower 36, combustion air blower 44, etc.) are operated and controlled.

Further, the temperature calculation means 116 calculates the detection temperature based on the detection signal from the temperature detection means 110, and the temperature difference calculation means 118 calculates the degree of temperature change of the detection temperature of the temperature detection means 110 (for example, one before). (Temperature difference from the detected temperature) is calculated, the temperature difference comparing means 120 compares the temperature difference calculated by the temperature difference calculating means 118 with the reference temperature difference (for example, 5 ° C.), and the abnormality determining means 122 determines. Based on the temperature change state of the detected temperature, the presence / absence of malfunction of the water supply valve 104, that is, the presence / absence of abnormality is determined as described later, and the abnormality signal generation means 124 is based on the abnormality determination of the abnormality determination means 122. Generate an abnormal signal.

The controller 112 further includes a memory means 132 and a timer means 134. The memory means 112 stores the change state (detection temperature, calculated temperature difference) of the detection temperature of the temperature detection means 110, the reference temperature difference, the sterilization processing temperature (for example, 60 ° C.), and the timer means 134 clocks. Various times, for example, the start time interval for performing the sterilization treatment (for example, 10 days), the purge treatment time for performing the purge treatment described later (for example, 50 minutes), and the sterilization treatment time for performing the sterilization treatment described later (for example, 30 minutes). Etc. are memorized. Further, the timer means 134 measures the start time interval, the purge processing time, the sterilization processing time, and the like described above.

In this embodiment, the operation of the power generation system is performed by the operation remote controller 136, which includes various operation buttons (not shown) and valve abnormality display means 138. The valve abnormality display means 138 is composed of an abnormality display lamp, an abnormality display unit of a liquid crystal display device, and the like, and the operation of the abnormality display means 138 causes a malfunction in the water supply valve 104 during the sterilization treatment operation. Display that.

Next, the operation of the above-mentioned power generation system will be described with reference to FIGS. 4 and 5 together with FIGS. 1 to 3. When the operation remote controller 136 is started and operated mainly with reference to FIGS. 3 and 5, the power generation system is started (step S1), and the above-mentioned power generation operation is performed (step S2). During this power generation operation, the fuel supply valve 32, the air supply valve 40, the discharge side fuel valve 64, the discharge side air valve 66, the heat recovery circulation valve 68 and the water supply valve 104 are held in the open state, and the circulation valve 100 is in the closed state. Is held in. In such a state, the fuel supply pump 30 operates, the raw fuel gas is supplied to the steam generating section 12 of the reformer 4 through the desulfurization device 20 through the fuel gas supply flow path 22, and the water supply pump 94 It operates and the condensed water (modified water) in the water recovery tank 88 is supplied to the steam generating unit 12 through the water supply flow path 90. In the steam generating section 12, the reformed water is vaporized to become steam, and the raw fuel gas and steam are sent to the reforming section 14 of the reformer 4 to perform steam reforming, and the reformed fuel gas (anodic gas). Is supplied to the fuel electrode 6 side of the cell stack 2 via the carbon monoxide reformer 16 and the carbon monoxide remover 18. Further, the air blower 36 operates, and air (cathode gas) is supplied to the air electrode 8 side of the cell stack 2.

In the cell stack 2, power is generated by a fuel cell reaction due to oxidation of the reformed fuel gas on the fuel electrode 6 side and reduction on the air electrode 8 side, and the power generation output is output from the power generation output line 108 through the inverter 106. To.

The reaction fuel gas (anodide off gas) from the fuel electrode 6 side of the cell stack 2 is supplied to the reformer burner 28 through the reaction fuel gas supply flow path 40, and is supplied as raw fuel through the branch fuel gas flow path 46. It is burned together with the gas and the fuel air supplied by the combustion air blower 44, and the combustion exhaust gas is discharged through the exhaust gas discharge flow path 46 and the composite heat exchanger 58. Further, the reaction air (cathode off gas) from the air electrode 8 side of the cell stack 2 is discharged through the air discharge flow path 48 and the composite heat exchanger 58.

During this power generation operation, the cooling water pump 78 is operated, the cooling water in the cooling water tank 88 is circulated through the cooling water circulation flow path 74, and the cooling portion 72 of the cell stack 2 is cooled by the circulating cooling water. Further, the circulation pump 56 of the hot water storage device 50 is operated, the water in the hot water storage tank 52 is circulated through the heat recovery circulation flow path 54 and the composite heat exchanger 58, and the exhaust gas discharge flow path 46 is circulated by the composite heat exchanger 58. After being heated by heat exchange with the flowing combustion exhaust gas and the reaction air flowing through the air discharge flow path 48, it is stored in the hot water storage tank 52 as hot water.

The heat exchange in the combined heat exchanger 58 cools the combustion exhaust gas and the reaction air, condenses the water contained in the combustion exhaust gas and the water contained in the reaction air, and the condensed water passes through the water recovery flow path 90. It is collected in the collection tank 88.

This is because the power generation operation of this power generation system becomes the start time for starting the sterilization process continuously for a predetermined time, in other words, when a predetermined time (for example, 10 days) has passed from the start of the previous sterilization process, the sterilization process needs to be performed. Then, the process proceeds from step S3 to step S4, and the power generation stop step of the power generation system is executed. In this power generation stop step, a steam purge process is performed (step S5). In this steam purging step, the fuel supply valve 32, the air supply valve 40, the discharge side fuel valve 64, and the discharge side air valve 66 are kept in a closed state, and the supply of raw fuel gas through the fuel gas supply flow path 22 is stopped. Then, the production of reformed fuel gas is stopped. On the other hand, the water supply valve 104 is kept in an open state, and the water supply pump 94 is operated (at this time, the rotation speed is operated at a lower rotation speed than in the power generation operation, for example), and the water recovery tank 88 is operated. The supply of condensed water (reforming water) from the reformer 4 is continued, steam is continuously generated in the steam generating section 12 of the reformer 4, and the generated steam is generated in the steam generating section 12 and the reforming section 14 of the reformer 4. , Is delivered into the carbon monoxide metamorphizer 16 and the carbon monoxide remover 18. Such steam purging treatment is performed for a purging treatment time (for example, 50 minutes), and by performing such a steam purging treatment, the steam generating part 12 and the reforming part 14 of the reformer 4, the carbon monoxide modifier 16 and one. The inside of the carbon oxide remover 18 is filled with steam and replaced.

When this steam purging process is completed, the sterilization operation of the condensed water in the water recovery tank 88 and the cooling water in the cooling water tank 76 is performed (step S5). In this sterilization treatment operation, the water supply valve 104 is held in the closed state and the circulation valve 100 is held in the open state (step S7). Further, the sterilization heater 96 is operated (step S8), and the water supply pump 94 is continuously operated (at this time, the rotation speed thereof is higher than that in the power generation operation). Then, as shown by an arrow in FIG. 2, the condensed water in the water recovery tank 88 is circulated through the water supply flow path 90, the circulation flow path 98, the cooling water tank 76, and the water circulation supply flow path 102. Further, the sterilization treatment heater 96 heats the cooling water in the cooling water tank 76, and the cooling water heated in the cooling water tank 76 is returned to the water recovery tank 88 through the water circulation feeding flow path 102 and circulated in this way. The temperature of the condensed water in the water recovery tank 88 and the cooling water in the cooling water tank 76 rises.

When such a sterilization treatment operation is started, the temperature detecting means 110 (temperature detecting means for the reformer) detects the temperature of the steam generating unit 12 of the reformer 4 (step S9), and the temperature calculating means 116 The detected temperature is calculated from the detection signal from the temperature detecting means 110 (step S10), and the malfunction of the water supply valve 104 is detected based on the temperature change state of the detected temperature.

Here, referring to FIG. 4, the reforming catalyst temperature of the reforming unit 14 of the reformer 4 during the power generation operation, the stop process (steam purge treatment), and the sterilization treatment operation, and the carbon monoxide modifier 16. Explaining the monoxide transformation catalyst temperature, the carbon monoxide removal catalyst temperature of the carbon monoxide remover 18, the cooling water temperature in the cooling water tank 76, and the condensed water temperature in the water recovery tank 88, the operation of the water supply valve 104 is performed. In the normal case, all the condensed water from the water recovery tank 88 flows into the circulation flow path 98, and does not flow to the downstream side (water vapor generation part 12 of the reformer 4) through the water supply valve 104. These temperatures change, for example, as shown by the solid line in FIG. 4, and the detection temperature of the temperature detecting means 110 rises with the passage of time because the condensed water (reforming water) does not flow to the water vapor generating portion 12. Will come to do.

On the other hand, when a malfunction occurs in the water supply valve 104, a part of the condensed water flowing from the water supply flow path 90 to the circulation flow path 98 passes through the water supply valve 104 to the steam generating part 12 of the reformer 4. Condensed water that has flowed to the downstream side is vaporized by the steam generating unit 12 to generate steam, and therefore, the surrounding heat is taken away by this vaporization, and the detection temperature of the temperature detecting means 110 is time. Almost no increase even after the lapse of time, and the temperature changes, for example, as shown by a broken line in FIG.

Therefore, the temperature difference calculating means 118 calculates the temperature difference of the detected temperature (that is, the degree of temperature rise) (step S11), and when the temperature difference is a predetermined temperature (for example, 5 ° C./min) or more. If there is, the process proceeds from step 12 to step S13 assuming that the water supply valve 104 is operating normally, and the sterilization treatment operation is continuously performed.

Then, when the temperature of the condensed water in the water recovery tank 88 reaches, for example, 60 ° C. during such a sterilization treatment operation, the process proceeds from step SS14 to step S15, and the temperature state of 60 ° C. is continuously maintained for 30 minutes. The operation of the sterilization heater 96 is controlled so as to be so. When this sterilization treatment is continued for 30 minutes, the sterilization treatment of the condensed water in the water recovery tank 88 and the cooling water in the cooling water tank 76 is completed on the assumption that the germs in the condensed water have died (step S16), and then the process returns to step S1. Then, the power generation system is started and the power generation operation is restarted.

On the other hand, the temperature difference calculating means 118 calculates the temperature difference of the detected temperature (that is, the degree of temperature rise) (step S11), and when this temperature difference is less than a predetermined temperature (for example, 5 ° C./min), water is used. Assuming that the supply valve 104 has malfunctioned, the process proceeds from step 12 to step S17, and the abnormality determining means 122 causes the water supply valve 104 to malfunction and the condensed water is transferred to the reformer 4 (steam generator 12). It is determined that an abnormality has occurred in the water supply valve 104 as if it is flowing, and the abnormality signal generation means 124 generates an abnormality signal based on the determination of the occurrence of the abnormality (step S18). Then, the sterilization processing operation (sterilization processing operation) is completed based on this abnormality signal (step S19), and the valve abnormality display means 138 of the operation remote controller 136 is operated based on this abnormality signal (step S20). By operating the valve abnormality displaying means 138, it can be known that a malfunction has occurred in the water supply valve 104.

When the sterilization process is completed in this way, the water supply valve 104 is inspected and repaired, and then the error is cleared (step S21). After the error is cleared, the process returns to step S1, the power generation system is started, and the power generation operation is restarted. Will be done.

In this power generation system, a temperature detecting means 110 (temperature detecting means for a reformer) is provided in the steam generating section 12 of the reformer 4, and the temperature of the steam generating section 12 is detected by the temperature detecting means 110 during the sterilization processing operation. Therefore, whether or not the water supply valve 104 has malfunctioned based on the fluctuation state of the detected temperature of the temperature detecting means 110 (in other words, whether or not the condensed water is flowing downstream through the water supply valve 104). Can be detected. Further, since the sterilization treatment operation is stopped when the water supply valve 104 malfunctions, it is possible to prevent the condensed water from flowing to the reformer 4 (steam generating unit 12).

In the sterilization treatment operation of the above-described embodiment, when the water supply valve 104 malfunctions, the sterilization treatment operation is simply stopped. Instead of such control, for example, FIG. 6 shows. It may be controlled as shown. In this operation control, when a malfunction occurs in the water supply valve 104, a recovery operation of the water supply valve 104 is performed, and the sterilization processing operation is restarted after this recovery operation. In this case, although not shown, the controller 112 further includes a valve recovery signal generation means for generating a valve recovery operation signal for the recovery operation, and the other configurations of the power generation system are substantially the same as the configurations described above. For other configurations, refer to FIGS. 1 to 3.

Explaining with reference to FIG. 6, when the temperature difference (that is, the degree of temperature rise) of the detected temperature of the temperature detecting means 110 is less than a predetermined temperature (for example, 5 ° C./min) in the sterilization processing operation, the water supply valve. The process proceeds from step S42 to step S47 on the assumption that a malfunction has occurred in 104, and the abnormality determination means 122 determines that an abnormality has occurred in the water supply valve 104 on the assumption that a malfunction has occurred in the water supply valve 104. Based on the determination of the occurrence of the abnormality, the abnormality signal generation means 124 generates an abnormality signal (step S48), and the sterilization processing operation (sterilization processing operation) is stopped based on the abnormality signal (step S49).

After the sterilization processing operation is stopped, the valve recovery signal generation means (not shown) further generates a valve recovery signal based on this abnormal signal, and the operation control means 114 (see FIG. 3) is based on this valve recovery signal. Opens and closes the water supply valve 104 a plurality of times (for example, 3 to 5 times), and thus the recovery operation of the water supply valve 104 is performed (step S50). At this time, if the water supply valve 104 malfunctions due to dust or the like, the dust or the like is removed by this recovery operation and the malfunction is resolved. After this recovery operation, the sterilization processing operation is restarted (step S51).

When the sterilization processing operation is restarted in this way, the temperature detecting means 110 again detects the temperature of the steam generating unit 12 of the reformer 4 (step S52), and the temperature calculating means 116 is transmitted from the temperature detecting means 110. The detection temperature is calculated from the detection signal of, and it is detected whether the operation of the water supply valve 104 is restored based on the temperature change state of the detection temperature.

That is, the temperature difference calculating means 118 calculates the temperature difference of the detected temperature (that is, the degree of temperature rise) (step S53), and when this temperature difference is equal to or higher than a predetermined temperature (for example, 5 ° C./min), water is used. Assuming that the operation of the supply valve 104 is restored, the process proceeds from step 54 to step S43, the sterilization processing operation is continuously performed, and the following steps S43 to 46 are executed. The operations executed in steps S43 to S46 are the same as the operations executed in steps S13 to S16 in the flowchart of FIG.

On the other hand, if the temperature difference (that is, the degree of temperature rise) of the detected temperature of the temperature detecting means 110 is less than a predetermined temperature (for example, 5 ° C./min), it is assumed that the operation of the water supply valve 104 has not recovered, and step S54. In step S55, the abnormality determining means 122 redetermines the occurrence of an abnormality in the water supply valve 104 on the assumption that the malfunction of the water supply valve 104 has not been recovered, and based on the determination of the occurrence of the abnormality, the abnormality signal generating means. 124 generates an abnormal signal (step S56), the sterilization processing operation (sterilization processing operation) is completed based on this abnormal signal (step S57), and steps S58 to S59 are further executed, and these steps S58 to S59 are executed. The operation executed in is the same as the operation executed in steps S20 to S21 in the flowchart of FIG. The operation executed in steps S31 to S42 in the flowchart of FIG. 6 is the same as the operation executed in steps S1 to S12 in the flowchart of FIG.

In the above-described embodiment, the malfunction of the water supply valve 104 is detected based on the temperature change state of the reformer 4 (for example, the steam generating unit 12) during the sterilization treatment operation, but the temperature of the reformer 4 is detected. Instead of the changed state, the malfunction of the water supply valve 104 is detected even based on the temperature change state of the cooling water temperature in the cooling water tank 76 or the condensed water temperature (reforming water temperature) in the water recovery tank 88. Can be done.

Explaining with reference to FIG. 7, one of the reforming catalyst temperature of the reforming unit 14 of the reformer 4 and the carbon monoxide modifier 16 during the power generation operation, the stop process (steam purge treatment) and the sterilization treatment operation. Regarding the oxidation transformation catalyst temperature, the carbon monoxide removal catalyst temperature of the carbon monoxide remover 18, the cooling water temperature in the cooling water tank 76, and the condensed water temperature in the water recovery tank 88, the water supply valve 104 operates normally. If this is the case, all of the condensed water from the water recovery tank 88 flows into the circulation flow path 98, so that the temperature changes as shown by the solid line in FIG. 7 (the temperature change states shown by these solid lines are shown in FIG. 4). It is the same as the temperature change state shown by the solid line).

On the other hand, when the water supply valve 104 malfunctions, the circulating flow rate of the condensed water circulated through the circulation flow path 98 as described above (in other words, the return flow rate of the condensed water to the water recovery tank 88). As a result, the temperature of the condensed water in the water recovery tank 88 hardly rises over time as shown by the broken line in FIG. 7. Therefore, the water recovery tank 88 It is possible to detect the malfunction of the water supply valve 104 even based on the temperature change state of the condensed water in the water supply valve 104.

For example, when the malfunction of the water supply valve 104 is detected based on the temperature change state of the cooling water in the cooling water tank 76, the flow of the detection operation is as shown in FIG. In this case, the temperature detecting means 110 (which functions as the cooling water temperature detecting means) is arranged in the cooling water tank 76 and detects the temperature of the cooling water in the cooling water tank 76.

In this operation control, when the sterilization treatment operation is started, the water supply valve 104 is held in the closed state, the circulation valve 100 is held in the open state (step S67), and the germ treatment heater 96 is operated (step S68). The temperature detecting means 110 (cooling water temperature detecting means) detects the temperature of the cooling water in the cooling water tank 76 (step S69). Then, the temperature calculation means 116 calculates the detection temperature by the detection signal from the temperature detection means 110 (step S70), and detects the malfunction of the water supply valve 104 based on the temperature change state of the detection temperature.

The temperature difference calculating means 118 calculates the temperature difference of the detected temperature (that is, the degree of temperature rise) (step S71), and when this temperature difference is equal to or less than a predetermined temperature (for example, 5 ° C./min), the water supply valve. Assuming that 104 is operating normally, the process proceeds from step 72 to step S73, the sterilization processing operation is continued, and steps S74 to S76 are executed. The operations executed in steps S74 to S76 are the same as the operations executed in steps S14 to S16 in the flowchart of FIG.

On the other hand, when the temperature difference of the detected temperature by the temperature difference calculating means 118 exceeds a predetermined temperature (for example, 5 ° C./min), it is assumed that the water supply valve 104 has malfunctioned, and the process proceeds from step 72 to step S77. The abnormality determining means 122 determines that an abnormality has occurred in the water supply valve 104 on the assumption that the circulating flow rate of condensed water is small due to a malfunction of the water supply valve 104, and based on the determination of this abnormality occurrence, the abnormality signal generating means 124 has an abnormality. A signal is generated (step S78), steps S79 to S81 are executed based on this abnormal signal, and the condensed water from the water recovery tank 88 is sent to the reformer 4 (steam generator 12) in the same manner as described above. It can be prevented from flowing. The operations executed in steps S79 to S81 are the same as the operations executed in steps S19 to S21 in the flowchart of FIG. Further, the operations executed in steps S61 to S66 are the same as the operations executed in steps S1 to S6 in the flowchart of FIG.

Further, for example, when the malfunction of the water supply valve 104 is detected based on the temperature change state of the condensed water in the water recovery tank 88, the flow of the detection operation is as shown in FIG. In this case, the temperature detecting means 110 (which functions as the temperature detecting means for reforming water) is arranged in the water recovery tank 88 and detects the temperature of the condensed water in the water recovery tank 88.

In this operation control, when the sterilization treatment operation is started, the water supply valve 104 is held in the closed state, the circulation valve 100 is held in the open state (step S97), and the germ treatment heater 96 is operated (step S98). The temperature detecting means 110 (temperature detecting means for reforming water) detects the temperature of the cooling water in the water recovery tank 88 (step S99). Then, the temperature calculation means 116 calculates the detection temperature by the detection signal from the temperature detection means 110 (step S100), and detects the malfunction of the water supply valve 104 based on the temperature change state of the detection temperature.

The temperature difference calculating means 118 calculates the temperature difference of the detected temperature (that is, the degree of temperature rise) (step S101), and when the temperature difference is equal to or higher than a predetermined temperature (for example, 5 ° C./min), the water supply valve. Assuming that 104 is operating normally, the process proceeds from step 102 to step S103, the sterilization processing operation is continued, and steps S104 to S106 are executed. The operation executed in steps S104 to S106 is the same as the operation executed in steps S14 to S16 in the flowchart of FIG.

On the other hand, if the temperature difference of the detection temperature by the temperature difference calculation means 118 is less than a predetermined temperature (for example, 5 ° C./min), it is assumed that the water supply valve 104 has malfunctioned, and the process proceeds from step 102 to step S107. The abnormality determining means 122 determines the occurrence of an abnormality in the water supply valve 104 on the assumption that the flow rate of the condensed water returning to the water recovery tank 88 is small due to the malfunction of the water supply valve 104, and generates an abnormality signal based on the determination of the occurrence of the abnormality. The means 124 generates an abnormal signal (step S108), steps S109 to S111 are executed based on this abnormal signal, and the condensed water from the water recovery tank 88 is generated by the reformer 4 (steam generation) as described above. It is possible to prevent the water from flowing to the part 12). The operation executed in steps S109 to S111 is the same as the operation executed in steps S19 to S21 in the flowchart of FIG. Further, the operations executed in steps S91 to S66 are the same as the operations executed in steps S1 to S6 in the flowchart of FIG.

In the above-described embodiment, the sterilization treatment heater 96 is arranged in the cooling water tank 96, the cooling water is heated in the cooling water tank 96, and the heated cooling water is passed through the water circulation feeding flow path 102 to the water recovery tank. Although the water is supplied to 88, the present invention is not limited to such a configuration, and the sterilization treatment heater 96 is arranged in the water recovery tank 88, and the condensed water is heated in the water recovery tank 88 to heat the condensed water. May be fed to the cooling water tank 76 through the circulation flow path 98.

In this case, as can be easily understood from the above description, if the water supply valve 104 has a malfunction during the sterilization treatment operation, the circulating flow rate of the condensed water circulated through the circulation flow path 98 as described above. (In other words, the return flow rate of the condensed water to the water recovery tank 88) is reduced. Therefore, regarding the temperature of the reformer 4 (steam generator 12) (that is, the temperature detected by the reformer temperature detecting means), if the water supply valve 104 malfunctions, condensed water is discharged to the reformer 4. Since water vapor is generated by flowing, there is almost no temperature rise, and the temperature rise is smaller than when the water supply valve 104 operates normally, and the water supply valve 104 operates using this temperature change state. Defects can be detected.

Regarding the temperature of the cooling water in the cooling water tank 76 (that is, the detection temperature of the cooling water temperature detecting means), if a malfunction occurs in the water supply valve 104, the circulation flow path 98 from the water recovery tank 88 Since the amount of condensed water flowing through the cooling water tank 76 is reduced, the degree of temperature rise is small, and the temperature rise is small compared to when the water supply valve 104 operates normally, and this temperature change state is used. However, it is possible to detect a malfunction of the water supply valve 104.

Further, regarding the temperature of the condensed water in the water recovery tank 88 (that is, the detection temperature of the temperature detecting means for reforming water), if the water supply valve 104 malfunctions, the circulation flow path 98 and the cooling water tank Since the amount of condensed water flowing to the water recovery tank 76 through the water circulation feed channel 102 and the water circulation channel 102 is reduced, the degree of the temperature rise is large, and the temperature rise is large compared to when the water supply valve 104 operates normally. Even if this temperature change state is used, the malfunction of the water supply valve 104 can be detected. Even when the germ treatment heater 96 is arranged in the water recovery tank 88 in this way, the same effects as described above can be achieved.

Next, a second embodiment of the power generation system according to the present invention will be described with reference to FIGS. 10 and 11. In the first embodiment described above, when a malfunction occurs in the water supply valve 104, the sterilization treatment operation is stopped to stop the operation of the entire power generation system, but in the second embodiment, the sterilization treatment operation is performed. It is configured to restart the power generation operation after it is stopped. The basic configuration of the power generation system of the second embodiment is the same as that of the first embodiment described above, but a configuration for restarting the power generation operation is added.

In FIG. 10, in the control system according to the second embodiment, the controller 112A includes an operation control means 114, a temperature calculation means 116, a temperature difference calculation means 118, a temperature difference leather means 120, an abnormality determination means 122, and an abnormality signal generation means. In addition to 124, the power generation restart signal generation means 152 is included. The power generation restart signal generation means 152 generates a power generation restart signal as described later. In this second embodiment, the temperature detecting means 110 (temperature detecting means for the reformer) is arranged in the water vapor generating unit 12 of the reformer 4, but as can be understood from the above description, the temperature detecting means (Temperature detecting means for cooling water) may be arranged in the cooling water tank 76 to detect the temperature of the cooling water, or the temperature detecting means (temperature detecting means for reforming water) may be placed in the water recovery tank 88. It may be arranged to detect the temperature of the condensed water. Further, although the sterilization treatment heater 96 is arranged in the cooling water tank 76 to heat the cooling water, it may be arranged in the water recovery tank 88 to heat the condensed water in the same manner as described above. ..

Also referring to FIG. 11, in the operation control in the power generation system of the second embodiment, when the sterilization treatment operation is started, the water supply valve 104 is held in the closed state and the circulation valve 100 is held in the open state (in the open state). Step S127), the sterilization heater 96 is activated (step S128), and the temperature detecting means 110 (temperature detecting means for the reformer) detects the temperature of the reformer 4 (steam generating unit 12) (step S129). Then, the temperature calculation means 116 calculates the detection temperature by the detection signal from the temperature detection means 110 (step S70), and detects the malfunction of the water supply valve 104 based on the fluctuation state of the detection temperature.

The temperature difference calculating means 118 calculates the temperature difference of the detected temperature (that is, the degree of temperature rise) (step S131), and when this temperature difference is less than a predetermined temperature (for example, 5 ° C./min), the water supply valve. Assuming that a malfunction has occurred in 104, the process proceeds from step 132 to step S137, and the abnormality determining means 122 assumes that condensed water is flowing to the reformer 4 (steam generator 12) due to the malfunction of the water supply valve 104. The occurrence of an abnormality is determined in the water supply valve 104, and the abnormality signal generation means 124 generates an abnormality signal based on the determination of the occurrence of the abnormality (step S138).

Then, the sterilization processing operation is completed based on this abnormality signal (step S139), and the valve abnormality display means 138 is operated based on this abnormality signal, indicating that the water supply valve 104 is malfunctioning. Notify (step S140). Further, the power generation restart signal generation means 152 generates a power generation restart signal based on this abnormal signal (step S141), the power generation operation is restarted based on the power generation restart signal, and the power generation operation is performed by returning to step S121. During this power generation operation, the valve abnormality display means 138 is held in the operating state, so that it is possible to know that the power generation operation is being performed in the temporary state. It is possible to shorten the downtime of the power generation operation of the system and improve the operation efficiency of the power generation system. When the water supply valve 104 is inspected and repaired, the power generation operation of the power generation system is stopped.

Although the embodiments of the power generation system according to the present invention have been described above, the present invention is not limited to these embodiments, and various changes or modifications can be made without departing from the scope of the present invention.

For example, in the above-described embodiment, the condensed water from the water recovery tank 88 is returned to the water recovery tank 88 via the circulation flow path 98, the cooling water tank 76, and the water circulation supply flow path 102 during the germ treatment operation. However, the present invention is not limited to such a configuration, and the circulation flow path 98 may be directly connected to the water recovery tank 88 and returned through the circulation flow path 98. In this case, the sterilization treatment heater 96 is arranged in the water recovery tank 88 to heat the condensed water in the water recovery tank 88, and the temperature detecting means 110 is arranged in the reformer 4 (steam generating unit 12). Install and detect the temperature (function as a temperature detecting means for reformer), or dispose of it in the water recovery tank 88 to detect the temperature of condensed water in the water recovery tank 88 (temperature for reforming water). It will function as a detection means).

When the temperature of the reformer 4 (steam generating unit 12) is detected (that is, used as a temperature detecting means for the reformer) in such a configuration, the water supply valve 104 malfunctions during the sterilization treatment operation. When it occurs, condensed water flows through the reformer 4 and steam is generated, so that the temperature rise is almost nonexistent, and the temperature rise becomes smaller than when the water supply valve 104 operates normally, and this temperature change. The state is used to detect a malfunction of the water supply valve 104.

Further, when the temperature of the cooling water in the water recovery tank 88 is detected (that is, used as a temperature detecting means for reforming water), if the water supply valve 104 malfunctions during the sterilization treatment operation, the water is recovered. Since the amount of condensed water returning to the tank 88 is reduced, the rate of temperature rise is large, and the temperature rise is large compared to when the water supply valve 104 operates normally, and water is supplied using this temperature change state. It comes to detect the malfunction of the valve 104.

Further, in the control flow shown in FIG. 6, when a malfunction of the water supply valve 104 occurs, the recovery operation of the water supply valve 104 (that is, a plurality of opening / closing operations) is executed. The recovery operation can also be applied to the control flow shown in FIG. 8, the control flow shown in FIG. 9, or the control flow shown in FIG.

2 Cell stack 4 Reformer 6 Fuel pole 8 Air pole 12 Steam generator 14 Reformer 28 Reformer burner 50 Hot water storage device 52 Hot water storage tank 58 Combined heat exchanger 70 Cooling water circulation structure 74 Cooling water circulation flow path 76 Cooling water tank 88 Water recovery tank 90 Water supply flow path 96 Sterilization treatment heater 98 Circulation flow path 100 Circulation valve 102 Water circulation supply flow path 104 Water supply valve 110 Temperature detection means 112, 112A Controller 120 Temperature difference calculation means 122 Abnormality determination means 124 Abnormality Signal generation means 138 Valve abnormality display means 152 Power generation restart signal generation means

Claims (7)

A fuel gas supply channel for supplying raw fuel gas, a reformer for steam reforming the raw fuel gas supplied through the fuel gas supply channel, and a reformed fuel reformed by the reformer. A cell stack that uses gas as an anode gas and air as a cathode gas to generate power, a cooling water tank for accommodating cooling water that cools the cell stack, and water contained in the exhaust gas to be condensed and recovered and stored. It is a power generation system equipped with a water recovery tank and feeds the condensed water collected in the water recovery tank as reformed water to the reformer through a water supply flow path.
A circulation flow path for returning the reformed water flowing through the water supply flow path to the cooling water tank is connected to the water supply flow path, and a circulation valve is provided in the circulation flow path. At the same time, a water circulation supply flow path for supplying the cooling water in the cooling water tank to the water recovery tank is provided between the cooling water tank and the water recovery tank, and the water supply flow path is provided. A water supply valve is provided on the downstream side of the connection site with the circulation flow path.
Further, the cooling water tank or the water recovery tank is provided with a heating means for heating and sterilizing the cooling water or the condensed water, and the reformer, the cooling water tank or the water. The recovery tank is provided with a reformer temperature detecting means, a cooling water temperature detecting means, or a reforming water temperature detecting means for detecting the temperature.
Further, in connection with the reformer temperature detecting means, the cooling water temperature detecting means, or the reforming water temperature detecting means, an abnormality determining means for determining the occurrence of an abnormality in the water supply valve is provided. Has been
During the power generation operation, the water supply valve is held in the open state, the circulation valve is held in the closed state, and the reformed water from the water recovery tank is supplied to the reformer through the water supply flow path. Further, when the sterilization treatment operation is performed, the heating means is operated, the water supply valve is held in the closed state, the circulation valve is held in the open state, and the water is heated in the cooling water tank or the water recovery tank. The cooling water or the reforming water is circulated through the water supply flow path, the circulation flow path, and the water circulation supply flow path, and the abnormality determination means is the reformer temperature detecting means and the cooling water temperature. A power generation system characterized in that an abnormality occurrence in the water supply valve is determined based on a temperature change state of the detecting means or the temperature detecting means for reforming water. An abnormality signal generation means for generating an abnormality signal is provided in connection with the abnormality determination means, and when the abnormality determination means determines the occurrence of an abnormality in the water supply valve, it is based on the determination of the occurrence of the abnormality. The power generation system according to claim 1 , wherein the abnormal signal generating means generates the abnormal signal, and the sterilization processing operation is stopped based on the abnormal signal. In connection with the abnormality determination means, a valve recovery operation signal generation means for generating a valve recovery operation signal for opening and closing the water supply valve a plurality of times is further provided, and the abnormality determination means supplies the water. When it is determined that an abnormality has occurred in the valve, the abnormality signal generating means generates the abnormality signal based on the determination of the occurrence of the abnormality, the sterilization processing operation is stopped based on the abnormality signal, and the valve. The claim is characterized in that the recovery operation signal generation means generates the valve recovery operation signal, the water supply valve is opened and closed a plurality of times based on the valve recovery operation signal, and then the sterilization processing operation is restarted. The power generation system according to 2 . When the abnormality determination means determines the occurrence of an abnormality in the water supply valve when the sterilization treatment operation is restarted, the abnormality signal generation means again outputs the abnormality signal based on the determination of the occurrence of the abnormality during the sterilization treatment operation. The power generation system according to claim 3 , wherein the sterilization processing operation is terminated based on the abnormal signal generated again. In connection with the abnormality determination means, a valve abnormality display means for notifying the occurrence of an abnormality in the water supply valve is further provided, and the abnormality determination means determines the occurrence of an abnormality in the water supply valve. The power generation system according to claim 2 , wherein the abnormality signal generation means generates the abnormality signal based on the determination of the occurrence of the abnormality, and the valve abnormality display means operates based on the abnormality signal. .. An abnormality signal generation means for generating an abnormality signal is provided in connection with the abnormality determination means, and when the abnormality determination means determines the occurrence of an abnormality in the water supply valve, it is based on the determination of the occurrence of the abnormality. The power generation system according to claim 1 , wherein the abnormal signal generation means generates the abnormal signal, the sterilization processing operation is terminated based on the abnormal signal, and then the power generation operation is restarted. In connection with the abnormality determination means, a valve abnormality display means for notifying the occurrence of an abnormality in the water supply valve is further provided, and the abnormality determination means determines the occurrence of an abnormality in the water supply valve. The power generation system according to claim 6 , wherein the abnormality signal generation means generates the abnormality signal based on the determination of the occurrence of the abnormality, and the valve abnormality display means operates based on the abnormality signal. ..

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