JP2006120421A - Fuel cell power generation system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell power generation system suppressing a decrease in power generation efficiency when performing continuous operation for a long time. <P>SOLUTION: The fuel cell power generation system comprises a fuel cell 20 that has a fuel electrode 21 for introducing fuel gas (g) that is rich in hydrogen and an air electrode 22 for introducing oxidizer gas a1 containing oxygen and generates power by the electrochemical reaction between the hydrogen in the fuel gas (g) and the oxygen in the oxidizer gas a1; voltage measurement means 24, 25 for measuring the generated voltage; and a control unit 40 for continuing to introduce the fuel gas (g) to the fuel electrode 21 when the measured voltage is equal to or smaller than a prescribed value and stopping the generation of the fuel cell 20 by stopping introducing the oxidizer gas a1 to the air electrode 22. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a fuel cell power generation system, and more particularly to a fuel cell power generation system that suppresses a decrease in power generation efficiency when performing continuous operation for a long time.

  As a fuel cell power generation system, a fuel cell that generates electricity and generates heat by an electrochemical reaction between hydrogen and oxygen, a fuel processing device that generates a fuel gas rich in hydrogen supplied to the fuel cell, and heat generated in the fuel cell It is known to have a hot water storage tank that stores water as a medium. A fuel cell is constructed by sandwiching an electrolyte between a fuel electrode and an air electrode, introducing a fuel gas rich in hydrogen into the fuel electrode, and introducing an oxidant gas containing oxygen into the air electrode to perform an electrochemical reaction. Wake up. Different types of catalysts are attached to the fuel electrode and the air electrode in order to promote the electrochemical reaction. The fuel processing apparatus includes a reforming unit that reforms the raw material fuel, and a carbon monoxide reducing unit that reduces carbon monoxide from a mixed gas containing hydrogen and carbon monoxide generated in the reforming unit. have. In the carbon monoxide reduction section, carbon monoxide is reduced by adding an oxygen-containing gas to the mixed gas to cause the carbon monoxide to undergo an oxidation reaction. The carbon monoxide reduction section is filled with a catalyst to promote the oxidation reaction.

  In general, the power generated by the fuel cell is used for power loads such as lights and electrical equipment outside the system, and the heat generated from the fuel cell during power generation is stored in a hot water storage tank, etc., to meet the heat demand outside the system. used. Conventional fuel cell power generation systems continue to operate the fuel cell power generation system to cover the demand with the power and heat generated by the fuel cell power generation system as much as possible when there is a power load and heat demand outside the system Was.

  However, it has been empirically recognized that if the fuel cell power generation system is continuously operated for a long time, the catalytic activity of the air electrode and the fuel electrode of the fuel cell and the catalytic activity of the carbon monoxide reduction unit of the fuel processing device are reduced. It is done. That is, if the fuel cell power generation system is continuously operated over a long period of time, the performance of the fuel cell and the fuel processing device is lowered, and the fuel cell power generation system is operated with low efficiency.

  In view of the above-described problems, an object of the present invention is to provide a fuel cell power generation system that suppresses a decrease in power generation efficiency when performing continuous operation for a long time.

  In order to achieve the above object, a fuel cell power generation system according to the first aspect of the present invention includes a fuel electrode 21 for introducing a fuel gas g rich in hydrogen and an oxidant containing oxygen, as shown in FIG. A fuel cell 20 having an air electrode 22 for introducing the gas a1 and generating electricity by an electrochemical reaction between hydrogen in the fuel gas g and oxygen in the oxidant gas a1, and voltage measurement for measuring the generated voltage Means 24, 25; by stopping the introduction of the oxidant gas a1 into the air electrode 22 while continuing the introduction of the fuel gas g into the fuel electrode 21 when the measured voltage becomes a predetermined value or less. And a control device 40 for stopping the power generation of the fuel cell 20.

  With this configuration, when the measured voltage becomes a predetermined value or less, the introduction of the oxidant gas to the air electrode is stopped while continuing the introduction of the fuel gas to the fuel electrode. It is possible to restore the catalytic activity of the air electrode by consuming oxygen remaining in the air electrode and lowering the air electrode in a reducing atmosphere before the efficiency of the air electrode decreases.

  Further, the fuel cell power generation system according to the second aspect of the present invention includes an anode 21 for introducing a fuel gas g rich in hydrogen and an air for introducing an oxidant gas a1 containing oxygen, as shown in FIG. A fuel cell 20 having an electrode 22 and generating electric power by an electrochemical reaction between hydrogen in the fuel gas g and oxygen in the oxidant gas a1, and measuring the cumulative time generated by the fuel cell 20; When the time reaches the first predetermined time, the introduction of the fuel gas g to the fuel electrode 21 is continued, and the introduction of the oxidant gas a1 to the air electrode 22 is stopped, thereby generating power from the fuel cell 20. And a control device 40 to be stopped.

  With this configuration, when the cumulative time generated by the fuel cell reaches the first predetermined time, the introduction of the oxidant gas to the air electrode is stopped while the introduction of the fuel gas to the fuel electrode is continued. Therefore, the catalytic activity of the air electrode can be restored by consuming oxygen remaining in the air electrode before the efficiency of the fuel cell power generation system is lowered and further placing the air electrode in a reducing atmosphere. The “first predetermined time” typically allows a decrease in the electrode catalyst activity of the fuel cell or a decrease in the catalyst activity of the carbon monoxide reduction unit in the fuel processing apparatus when the fuel cell is continuously operated. It is the operating time of the range.

  Moreover, the fuel cell power generation system according to the invention described in claim 3 is the fuel cell power generation system 1 according to claim 1 or 2, as shown in FIG. After a predetermined number of times of control for stopping the introduction of the oxidant gas a1 to the air electrode 22 while continuing the introduction of the fuel gas g to the air electrode 22, the fuel to the fuel electrode 21 is allowed while introducing the oxygen to the air electrode 22 Control is performed to stop the power generation of the fuel cell 20 by stopping the introduction of the gas g.

  With this configuration, the introduction of the fuel gas to the fuel electrode is stopped while allowing the introduction of oxygen to the air electrode, so that the catalytic activity of the fuel electrode can be restored. The “predetermined number of times” is determined in consideration of the degree of progress of the decrease in the catalytic activity of the air electrode and the fuel electrode.

  A fuel cell power generation system according to a fourth aspect of the present invention is the fuel cell system 1 according to any one of the first to third aspects, for example, as shown in FIG. A hot water storage tank 31 for storing the generated heat as water as a medium; a heat storage amount detection means 32 for detecting the heat storage amount stored in the hot water storage tank 31; and supply to an external power load among the electric power generated by the fuel cell 20 An external power load detecting means 28 for detecting the power to be generated; in addition to the condition for stopping the power generation of the fuel cell 20 described above, the heat storage amount detected by the heat storage amount detecting means 32 is equal to or greater than a predetermined heat amount and the external power load And a control device 40 that stops power generation in the fuel cell 20 when the power consumption detected by the detection means 28 is equal to or lower than a predetermined power.

  With this configuration, in addition to the above-described conditions for stopping the power generation of the fuel cell, the power generation in the fuel cell is stopped when the heat storage amount is equal to or greater than the predetermined heat amount and the power consumption is equal to or less than the predetermined power. The fuel cell can be stopped when there is little demand for heat generation and power generation in the fuel cell. The “external power load” is a power load outside the fuel cell power generation system, and therefore does not include auxiliary devices in the system.

  Further, the fuel cell power generation system according to the invention described in claim 5 is the fuel cell system 1 according to any one of claims 1 to 3, for example, as shown in FIG. A hot water storage tank 31 for storing the generated heat as water as a medium; a heat storage amount detection means 32 for detecting the heat storage amount stored in the hot water storage tank 31; and supply to an external power load among the electric power generated by the fuel cell 20 The external power load detecting means 28 for detecting the power to be recorded; the fluctuation of the heat storage amount during the day is recorded on the basis of the heat storage amount detected by the heat storage amount detecting means 32 and detected by the external power load detecting means 28 Record fluctuations in power consumption during the day based on power consumption, and based on recording heat storage and power consumption, the amount of heat stored in the day is greater than or equal to the specified amount of heat, and the power consumption is the specified power. When expected to be The band, when provided with the condition for stopping the power generation of the aforementioned fuel cell 20, and a control unit 40 to stop the power generation in the fuel cell 20.

  If comprised in this way, the condition which stops the electric power generation of the above-mentioned fuel cell was comprised in the time slot | zone when it is anticipated that the heat storage amount will be more than predetermined | prescribed amount of heat within a day, and power consumption will be below predetermined | prescribed electric power. Occasionally, since power generation in the fuel cell is stopped, it is possible to stop the fuel cell in a time zone in which it is expected that there is little demand for heat generation and power generation in the fuel cell.

  Further, the fuel cell power generation system according to the invention described in claim 6 is the control device 40 in the fuel cell power generation system 1 according to any one of claims 1 to 5, for example, as shown in FIG. Restarts the power generation of the fuel cell 20 after the second predetermined time has elapsed after the power generation of the fuel cell 20 is stopped. Here, the resumption of power generation of the fuel cell means that when the introduction of the oxidant gas to the air electrode is stopped, the introduction of the fuel gas to the fuel electrode is stopped by the resumption of the introduction of the oxidant gas to the air electrode. Is performed by resuming the introduction of the fuel gas to the fuel electrode. To resume the introduction of the fuel gas to the fuel electrode, once the introduction of the oxidant gas to the air electrode is stopped, the fuel gas is introduced to the fuel electrode. The case where the fuel gas is restarted in this order and the introduction of the oxidant gas to the air electrode is also included.

  With this configuration, the power generation of the fuel cell is resumed after the second predetermined time has elapsed after the power generation of the fuel cell 20 is stopped. The power generation is resumed, and a decrease in the power generation performance of the fuel cell can be suppressed. The “second predetermined time” is typically a time required until the catalytic activity of the fuel cell is restored.

  A fuel cell power generation system according to the invention described in claim 7 is the fuel cell power generation system 1 according to any one of claims 1 to 6, as shown in FIG. Is reformed to generate a mixed gas r containing hydrogen and carbon monoxide, a combustion section 11 for supplying heat necessary for reforming to the reforming section 13, and an oxygen-containing gas a2. And the mixed gas r to reduce the carbon monoxide in the mixed gas r to generate the fuel gas g, and the fuel processing apparatus 10 having the carbon monoxide reducing unit 14 that generates the fuel gas g; When the introduction is stopped, the fuel gas g generated by the fuel processing device 10 is introduced into the combustion unit 11 by bypassing the fuel electrode 21, and the introduction of the oxygen-containing gas a2 into the carbon monoxide reduction unit 14 is stopped. And a control device 40 that performs control.

  If comprised in this way, since the fuel gas produced | generated with the fuel processing apparatus bypasses a fuel electrode and introduce | transduces into a combustion part, and introduction | transduction of the oxygen-containing gas to a carbon monoxide reduction part is stopped, The generation of the mixed gas containing hydrogen can be continued to restore the catalytic activity of the carbon monoxide reducing portion with the mixed gas.

  According to the present invention, when the measured voltage falls below a predetermined value, or when the accumulated time generated by the fuel cell reaches the first predetermined time, the fuel gas is introduced into the fuel electrode. Since the introduction of the oxidant gas to the air electrode is stopped while continuing, the catalytic activity of the air electrode of the fuel cell can be restored, and a decrease in power generation efficiency can be suppressed when performing continuous operation for a long time.

Hereinafter, a fuel cell power generation system according to an embodiment of the present invention will be described with reference to the drawings. In FIG. 1, a broken line represents a control signal.
First, a configuration of a fuel cell power generation system 1 according to an embodiment of the present invention will be described with reference to FIG. FIG. 1 is a schematic system diagram illustrating a fuel cell power generation system 1 according to an embodiment of the present invention. The fuel cell power generation system 1 includes a fuel processing device 10, a fuel cell 20, a hot water storage tank 31, and a control device 40. Hereinafter, these configurations will be described in order.

  The fuel processing apparatus 10 is an apparatus that introduces a raw material fuel m and reforming water s, and reforms the raw material fuel m to generate a fuel gas g rich in hydrogen. The fuel processing apparatus 10 includes a combustion unit 11, a water vapor generation unit 12, a reforming unit 13, and a carbon monoxide reduction unit 14.

  The combustion unit 11 is configured to generate reforming heat necessary for reforming the raw material fuel m. The combustion unit 11 typically has a burner, and is configured to introduce the combustion fuel m1 and the combustion air a3 and burn the combustion fuel m1 to generate reforming heat. Has been. The raw material fuel m may be used as the combustion fuel m1, or another fuel may be used. Further, the anode off gas p derived from the fuel electrode 21 of the fuel cell 20 may be introduced and burned instead of the combustion fuel m1, or the fuel gas g generated by the fuel processing apparatus 10 is introduced and burned. You may let them. The anode off-gas p is a gas containing hydrogen that is discharged from the fuel gas introduced into the fuel electrode 21 of the fuel cell 20 without being used for an electrochemical reaction. The combustion fuel m1 or anode offgas p or fuel gas g burned in the combustion unit 11 is discharged from the combustion unit 11 as exhaust gas e. The combustion unit 11 and the fuel electrode 21 of the fuel cell 20 are connected via a flow path 53.

  The water vapor generating unit 12 is configured to introduce and heat the reforming water s to produce water vapor necessary for reforming the raw material fuel m. A flow path 50 for introducing the reforming water s is connected to the water vapor generating unit 12. A reforming water control valve 17 is disposed in the flow path 50. When the reforming water control valve 17 opens and closes, the introduction amount of the reforming water s into the steam generation unit 12 can be adjusted or stopped. A signal cable is laid between the reforming water control valve 17 and the control device 40, and the reforming water control valve 17 can receive a signal from the control device 40 and adjust the opening of the valve. It is configured as follows. The water vapor generation unit 12 is installed adjacent to the combustion unit 11 and the carbon monoxide reduction unit 14, and uses heat released from the combustion unit 11 and the carbon monoxide reduction unit 14 for the heat of vaporization of the reforming water s. It is preferable.

  The reforming unit 13 is configured to introduce and reform the raw material fuel m to generate a mixed gas r containing hydrogen as a main component and containing carbon monoxide. The reforming unit 13 is configured to introduce the steam generated by the steam generating unit 12 in addition to the raw material fuel m, obtain reforming heat from the combustion unit 11, and cause the raw material fuel m to undergo a steam reforming reaction. Yes. The reforming unit 13 is filled with a reforming catalyst for promoting the reforming reaction. As the reforming catalyst, a nickel-based reforming catalyst or a ruthenium-based reforming catalyst is typically used.

  The raw material fuel m introduced into the reforming unit 13 is typically a gas raw material fuel such as city gas, LPG, digestion gas, or methanol, or a liquid raw material fuel such as GTL (Gas to Liquid) or kerosene. Used. In order to avoid sulfur poisoning of the reforming catalyst, the raw material fuel m is preferably introduced into the reforming unit 13 after being desulfurized by a desulfurizer (not shown). The gaseous raw material fuel m is configured to be pumped to the reforming unit 13 by the blower 18. When the raw material fuel m is liquid, a pump is used instead of the blower 18. Further, when the raw material fuel m is liquid, it is preferable to provide a vaporizer on the upstream side of the reforming unit 13. The heat of vaporization for vaporizing the liquid raw material fuel m may be the heat of the combustion section 11.

  The carbon monoxide reduction unit 14 is configured to introduce the mixed gas r, add the oxygen-containing gas a2 to the mixed gas r, and reduce the carbon monoxide in the mixed gas r to generate the fuel gas g rich in hydrogen. Yes. The oxygen-containing gas a2 is typically air. The “hydrogen-rich fuel gas” is a gas containing 40% or more of hydrogen, typically about 75%. It is preferable that the carbon monoxide reduction unit 14 is further divided into a transformation unit 15 and a selective oxidation unit 16 so as to efficiently reduce carbon monoxide from the mixed gas r.

  The shift unit 15 is filled with a shift catalyst, and is configured to generate a shift gas h rich in hydrogen by introducing the mixed gas r and reducing carbon monoxide in the mixed gas r. As the shift catalyst, typically, an iron-chromium shift catalyst, a copper-zinc shift catalyst, a platinum shift catalyst, or the like is used.

  The selective oxidation unit 16 is filled with a selective oxidation catalyst, introduces the modified gas h, adds an oxygen-containing gas a2, and further reduces the carbon monoxide from the modified gas h to produce a fuel gas g rich in hydrogen. Configured to generate. As the selective oxidation catalyst, a platinum-based selective oxidation catalyst, a ruthenium-based selective oxidation catalyst, a platinum-ruthenium-based selective oxidation catalyst, or the like is typically used. The selective oxidation unit 16 is connected to a flow path 51 for introducing the oxygen-containing gas a2. An oxygen-containing gas control valve 19 is disposed in the flow path 51. When the oxygen-containing gas control valve 19 opens and closes, the amount of oxygen-containing gas a2 introduced into the selective oxidation unit 16 can be adjusted or stopped. A signal cable is laid between the oxygen-containing gas control valve 19 and the control device 40, and the oxygen-containing gas control valve 19 can receive a signal from the control device 40 and adjust the opening of the valve. It is configured as follows. Further, the selective oxidation unit 16 and the fuel electrode 21 of the fuel cell 20 are connected via a flow path 52. Further, a bypass channel 54 is provided between the channel 52 and the channel 53, and the fuel gas g generated by the selective oxidation unit 16 is directly introduced without being introduced into the fuel electrode 21 of the fuel cell 20. It is configured so that it can be guided to the combustion section 11. A bypass control valve 41 is disposed in the bypass channel 54 so that the flow rate of the fuel gas g flowing in the bypass channel 54 can be adjusted. A signal cable is laid between the bypass control valve 41 and the control device 40, and the bypass control valve 41 is configured to receive a signal from the control device 40 and adjust the opening of the valve. ing.

  The fuel cell 20 introduces a fuel gas g rich in hydrogen and an oxidant gas a1 containing oxygen, and generates heat by an electrochemical reaction between hydrogen in the fuel gas g and oxygen in the oxidant gas a1. It is a device that generates moisture. The fuel cell 20 is typically a polymer electrolyte fuel cell. The fuel cell 20 is configured by stacking a plurality of cells each having an electrolyte (not shown) sandwiched between a fuel electrode 21 and an air electrode 22. A cooling unit 23 is provided at an appropriate location between the stacked cells.

  The fuel electrode 21 is configured to introduce the fuel gas g and discharge the anode off gas p. As described above, the anode off gas p is an off gas containing hydrogen that has not been used for the electrochemical reaction in the fuel gas g. The fuel electrode 21 is typically configured by attaching a platinum-ruthenium catalyst to a carbon support. The fuel electrode 21 is connected to a flow path 52 for introducing the fuel gas g and a flow path 53 for discharging the anode off gas p. A fuel gas control valve 42 is disposed in the flow path 52. A signal cable is laid between the fuel gas control valve 42 and the control device 40. The fuel gas control valve 42 is configured to receive a signal from the control device 40, adjust the opening of the valve, and adjust the flow rate of the fuel gas g introduced into the fuel electrode 21. On the other hand, an anode off gas on-off valve 43 is disposed in the flow path 53. A signal cable is laid between the anode off gas on-off valve 43 and the control device 40. The anode off gas on-off valve 43 is configured to receive a signal from the control device 40 and to open and close the valve.

  The air electrode 22 is configured to introduce the oxidant gas a1 and discharge the cathode offgas q. The cathode off-gas q is an off-gas in which a gas that is not used for the electrochemical reaction in the oxidant gas a1 and water generated by the electrochemical reaction are mixed. The air electrode 22 is typically configured by attaching a platinum catalyst to a carbon support. A flow path 55 for introducing the oxidant gas a1 and a flow path 56 for discharging the cathode offgas q are connected to the air electrode 22. An oxidant gas control valve 44 is disposed in the flow path 55. A signal cable is laid between the oxidant gas control valve 44 and the control device 40. The oxidant gas control valve 44 is configured to receive a signal from the control device 40, adjust the opening of the valve, and adjust the flow rate of the oxidant gas a1 introduced into the air electrode 22. . Further, a blower (not shown) is disposed in the flow path 55 so that the oxidant gas a1 can be pumped to the air electrode 22. On the other hand, a cathode offgas on / off valve 45 is disposed in the flow path 56. A signal cable is laid between the cathode offgas on-off valve 45 and the control device 40. The cathode offgas on / off valve 45 is configured to receive a signal from the control device 40 and to open and close the valve.

  The cooling unit 23 is configured to carry out heat generated by an electrochemical reaction from the fuel cell 20 using the cooling water c as a medium. A circulation channel 58 is connected to the cooling unit 23. The circulation channel 58 is provided with a heat exchanger 33 and a cooling water pump 35, and the temperature of the cooling water c led out from the cooling unit 23 is lowered by the heat exchanger 33 to cool the cooling water c that has fallen. The water pump 35 can be pumped to the cooling unit 23.

  A cell voltage measuring device 24 capable of measuring the voltage of individual cells among the plurality of stacked cells is connected to the fuel cell 20. In addition, the fuel cell 20 in FIG. 1 actually shows a simplified diagram of a plurality of stacked cells. A signal cable is laid between the cell voltage measuring device 24 and the control device 40, and the voltage of each cell measured by the cell voltage measuring device 24 can be transmitted to the control device 40 as needed as a signal. Has been. The cells whose voltages are measured by the cell voltage measuring instrument 24 are typically all the cells of the fuel cell 20, but some suitable cells may be selected. Moreover, you may make it measure a voltage not only for every one cell but for several cells.

  The fuel cell 20 is connected to cables 29a and 29b through which a current generated by an electrochemical reaction flows. A cable 29a is connected to the air electrode 22, and a cable 29b is connected to the fuel electrode 21, and the fuel cell 20 and the power conditioner 28 are connected by cables 29a and 29b. The power generated by the fuel cell 20 is DC power, and the current flows from the air electrode 22 toward the fuel electrode 21 via the cable 29a, the power conditioner 28, and the cable 29b. An ammeter 26 that measures the current from the fuel cell 20 is disposed on the cable 29a. A signal cable is laid between the ammeter 26 and the control device 40 so that the current measured by the ammeter 26 can be transmitted as a signal to the control device 40 at any time. The cables 29a and 29b are provided with a voltmeter 25 for measuring the voltage of the entire fuel cell 20. A signal cable is laid between the voltmeter 25 and the control device 40 so that the voltage of the entire fuel cell 20 measured by the voltmeter 25 can be transmitted to the control device 40 as a signal at any time. Yes.

  A power conditioner 28 connected to the fuel cell 20 via cables 29a and 29b is a device that converts DC power into AC power. The power conditioner 28 switches between a power source transmitted to an external power load outside the system as power generated by the fuel cell 20 or system power outside the system (typically commercial power) and both powers. The ratio can be changed. A cable 68 is connected to the power conditioner 28 so that the converted AC power can be supplied to an external power load such as a lamp or an electric device. Further, the power conditioner 28 can detect the power supplied to the external power load, and also functions as an external power load detection means. Strictly speaking, the power supplied to the external power load is the power consumed by the external power load plus the power transmission loss, but here, the power supplied to the external power load is ignored for the sake of convenience. A description will be given assuming that the power consumed by the external power load is the same. A signal cable is laid between the power conditioner 28 and the control device 40 so that the detected external power load can be transmitted as a signal to the control device 40 at any time. Note that an external power load detector may be separately provided in the cable 68 without the power conditioner 28 having a function as an external power load detection means. Further, the power conditioner 28 may include a voltage drop resistor.

  The hot water storage tank 31 is a tank that stores heat generated in the fuel cell 20 using water as a medium. The heat stored in the hot water storage tank 31 is typically consumed by heat demand such as hot water supply or heating outside the system. A circulation channel 59 is connected to the hot water storage tank 31, and a heat exchanger 33 and a circulation pump 34 are provided in the circulation channel 59. The circulation channel 59 is configured by connecting the upper and lower parts of the hot water storage tank 31 so that low temperature water flows out from the lower part of the hot water storage tank 31 and high temperature water flows into the upper part of the hot water storage tank 31. It is configured. Note that the “water” described here does not consider the temperature, and the water entering and exiting the hot water storage tank 31 is so-called “hot water” in consideration of the temperature. The temperature distribution in the hot water storage tank 31 is so-called temperature stratification in which the temperature at the upper part is high and the temperature is lowered as it goes to the lower part. In addition, the hot water storage tank 31 has an external flow path 61 for deriving high-temperature water toward heat demand outside the system, and external water flow path 61 for water whose temperature has been reduced due to heat consumption outside the system. The external flow path 62 introduced into the lower part is connected.

  The hot water storage tank 31 is typically a sealed tank. The hot water storage tank 31 is provided with a heat storage amount detector 32 as a heat storage amount detection means capable of detecting the heat storage amount in the hot water storage tank 31. The heat storage amount detector 32 includes a plurality of thermometers 32a to 32e. By disposing the thermometers 32 a to 32 e in the vertical direction of the hot water storage tank 31, the heat storage amount detector 32 is configured to detect the heat storage amount from the temperature distribution in the vertical direction of the hot water storage tank 31. A signal cable is laid between the heat storage amount detector 32 and the control device 40 so that the heat storage amount of the hot water storage tank 31 detected by the heat storage amount detector 32 can be transmitted as a signal to the control device 40 at any time. It is configured.

  The control device 40 receives signals from the cell voltage measuring device 24, the voltmeter 25, and the ammeter 26, makes the following determination, and sends it to the oxidant gas control valve 44 or the bypass control valve 41 and the fuel gas. A signal can be transmitted to the control valve 42 and the oxygen-containing gas control valve 19. The determination in the control device 40 is that the lowest cell voltage measured by the cell voltage measuring instrument 24 or the voltage of the fuel cell 20 measured by the voltmeter 25 is a predetermined voltage corresponding to the current value measured by the ammeter 26. When the following occurs, the oxidant gas control valve 44 is fully closed, or the bypass control valve 41 is opened and the fuel gas control valve 42 and the oxygen-containing gas control valve 19 are fully closed. The value of the predetermined voltage corresponding to the current value measured by the ammeter 26 that triggers the operation of the control valve in this way is the cell voltage measured by the cell voltage meter 24 or measured by the voltmeter 25. It differs depending on the voltage of the fuel cell 20. Hereinafter, a predetermined voltage value corresponding to the current value measured by the ammeter 26 when compared with the cell voltage measured by the cell voltage measuring device 24 is referred to as a “first predetermined value” and the fuel measured by the voltmeter 25. A predetermined voltage value corresponding to the current value measured by the ammeter 26 when compared with the voltage of the battery 20 is referred to as a “second predetermined value”.

  Here, the relationship between the current value measured by the ammeter 26 and a predetermined voltage will be described with reference to FIG. FIG. 2 is a graph showing the relationship between the current and voltage of the fuel cell 20. The vertical axis of the graph is voltage (the scale of the voltage of the entire fuel cell (stack voltage) is shown on the left side of the graph and the scale of the cell voltage is shown on the right side), and the horizontal axis is the current. In the figure, a curve STN represents the voltage of the entire fuel cell with respect to the generated current during steady operation (when the catalytic activity of the fuel cell 20 is not reduced). A curve STD represents a second predetermined voltage value corresponding to the current value measured by the ammeter 26.

  A curve CLN represents a voltage (average cell voltage) that each cell constituting the fuel cell 20 has with respect to a generated current during a certain operation (regardless of the catalyst activity of the fuel cell 20). The curve CLN shows a low voltage value when the catalytic activity of the fuel cell 20 decreases, and on the other hand, shows a high voltage value immediately after recovering the catalytic activity. A curve CLD represents a voltage obtained by reducing a certain voltage from the curve CLN (average cell voltage). The voltage value indicated by the curve CLD corresponds to the first predetermined voltage value.

  The control device 40 determines that the voltage of the cell indicating the lowest voltage value among the cell voltages measured by the cell voltage measuring device 24 (or the cell in which the voltage is collected for a plurality of cells) is from the curve CLN. The control valve is configured to operate as described above when the calculated curve CLD is below or when the voltage of the fuel cell 20 measured by the voltmeter 25 is below the curve STD (see paragraph 0039). ). For example, when the current value measured by the ammeter 26 is 15 A, the voltage of the cell indicating the lowest voltage value among the single cell voltages measured by the cell voltage measuring device 24 is 0. 0 from the curve CLN indicating the average cell voltage. When the voltage drops by 15 V (when the voltage is measured for each of a plurality of cells, the voltage of the grouped cells (for example, the total voltage of three cells when the voltage is measured for every three cells) is 0. When the voltage drops by 15 V), control as described above is performed. Alternatively, when the current value measured by the ammeter 26 is 15 A, the control as described above is performed when the voltage of the entire fuel cell 20 measured by the voltmeter 25 becomes 38 V or less.

  Returning to FIG. 1 again, the configuration of the fuel cell power generation system 1 will be described. The control device 40 also measures the accumulated time generated by the fuel cell 20 based on the signal received from the ammeter 26, and when the accumulated time reaches the first predetermined time, the controller 40 controls the oxidant gas control valve 44. A signal is transmitted so that the oxidant gas control valve 44 can be fully closed. Alternatively, when the accumulated time reaches the first predetermined time, a signal is transmitted to the bypass control valve 41, the fuel gas control valve 42, and the oxygen-containing gas control valve 19 to open the bypass control valve 41, and the fuel gas The control valve 42 and the oxygen-containing gas control valve 19 are configured to be fully closed. Here, the “first predetermined time” can allow a decrease in the electrode catalyst activity of the fuel cell 20 or a decrease in the catalyst activity of the selective oxidation unit 16 of the fuel processing apparatus 10 when the fuel cell 20 is continuously operated. It is the operating time of the range. Since the first predetermined time is measured regardless of the magnitude of the generated current, the first predetermined time is determined based on the maximum current by looking at the safe side.

  Moreover, the control apparatus 40 receives the signal from the power conditioner 28 and the heat storage amount detector 32, and in addition to the above-mentioned fall of the voltage or progress of the 1st predetermined accumulation time, the heat storage amount of the hot water storage tank 31 is increased. When the heat storage amount is equal to or greater than a predetermined amount of heat and the power consumption of the external power load is equal to or less than the predetermined power, the oxidant gas control valve 44 or the bypass control valve 41, the fuel gas control valve 42, and the oxygen-containing gas control valve 19 are used. It is comprised so that a signal can be transmitted to. At this time, the oxidant gas control valve 44 that has received the signal is fully closed. Further, the bypass control valve 41 is opened and the fuel gas control valve 42 and the oxygen-containing gas control valve 19 are fully closed.

  Moreover, the control apparatus 40 is comprised so that the fluctuation | variation of the heat storage amount and power consumption in one day can be recorded based on the signal from the power conditioner 28 and the heat storage amount detector 32 which are received at any time. In addition to the above-described decrease in voltage or elapse of the first predetermined cumulative time, the control device 40 is based on the recorded heat storage amount and fluctuations in power consumption. In addition, a signal is transmitted to the oxidant gas control valve 44, or to the bypass control valve 41, the fuel gas control valve 42, and the oxygen-containing gas control valve 19 in a time zone in which the power consumption is expected to be equal to or lower than the predetermined power. It may be configured to be able to. At this time, the oxidant gas control valve 44 that has received the signal is fully closed. Further, the bypass control valve 41 is opened and the fuel gas control valve 42 and the oxygen-containing gas control valve 19 are fully closed.

  Subsequently, the operation of the fuel cell power generation system 1 according to the embodiment of the present invention will be described with reference to FIGS. 3 and 4 in addition to FIG. FIG. 3 is a flowchart for explaining the operation of the fuel cell power generation system 1 according to the embodiment of the present invention. Moreover, FIG. 4 is a figure which shows the state of each control valve of the fuel cell power generation system 1 which concerns on embodiment of this invention for every process in the flowchart of FIG. In FIG. 4, “open” is a state in which the valve opening is adjusted according to the required amount of gas flowing inside, and “fully closed” is a state in which the gas flow is blocked. .

In the fuel processing apparatus 10, the fuel gas g is generated as follows (S201). The raw material fuel m as the combustion fuel m1 and the combustion air a3 are introduced into the combustion section 11, and the raw material fuel m is burned. The reforming water s is introduced into the steam generation unit 12 and receives heat from the combustion unit 11 to generate steam. The generated water vapor and the raw material fuel m are introduced into the reforming unit 13 to obtain reforming heat, the raw material fuel m is reformed by a steam reforming reaction, and a mixed gas r in which hydrogen and carbon monoxide are mixed. Is generated. For example, when the raw material fuel m is methane, the steam reforming reaction shown in the following equation (1) is performed.
CH ₄ + H ₂ O → 3H ₂ + CO (1)
The mixed gas r is introduced from the reforming section 13 to the shift section 15 and undergoes a shift reaction with water vapor represented by the following equation (2) to generate a shift gas h. Although not shown in the formula (2), the shift gas h contains carbon monoxide that has not been subjected to shift reaction.
CO + H ₂ O → H ₂ + CO ₂ (2)
The shift gas h is introduced from the shift section 15 to the selective oxidation section 16 and a selective oxidation reaction is performed by introducing the oxygen-containing gas a2. By the selective oxidation reaction, the modified gas h becomes a hydrogen-rich fuel gas g that contains almost no carbon monoxide. The selective oxidation reaction is represented by the following formula (3).
2CO + O ₂ → 2CO ₂ (3)
As described above, the fuel gas g is generated in the fuel processing apparatus 10 (S201). At this time, as shown in FIG. 4, the oxygen-containing gas control valve 19 is open.

  The fuel gas g generated by the fuel processing apparatus 10 is introduced into the fuel electrode 21 of the fuel cell 20. On the other hand, the oxidant gas a1 is introduced into the air electrode 22 (S202). In the fuel cell 20 into which the fuel gas g and the oxidant gas a1 are introduced, power is generated by an electrochemical reaction between hydrogen in the fuel gas g and oxygen in the oxidant gas a1, and heat is generated (S203). After the electrochemical reaction, the anode offgas p is discharged from the fuel electrode 21 and the cathode offgas q is discharged from the air electrode 22. The anode off gas p contains hydrogen and is led to the combustion unit 11 of the fuel processing apparatus 10 and burned to generate reforming heat. When the anode off gas p is introduced into the combustion section 11, the introduction of the combustion fuel m1 and the combustion air a3 is stopped. The DC power generated by the fuel cell 20 is converted to AC power by the power conditioner 28, transmitted to an external power load outside the system, and consumed. In addition, when the fuel cell power generation system 1 is stopped or at the start of starting, if the necessary power is insufficient with only the power generated by the fuel cell 20, the necessary power is supplied from the system power outside the system. . The power conditioner 28 switches the connection of the generated power and the grid power to the external power load in the fuel cell 20.

  On the other hand, the heat generated during the electrochemical reaction in the fuel cell 20 is taken away by the cooling water c passing through the cooling unit 23 and carried out of the fuel cell 20. The heat taken away by the cooling water c is transmitted to the hot water u flowing through the flow path 59 by the heat exchanger 33. The hot water u received from the cooling water c is introduced into the hot water storage tank 31, and the heat is stored in the hot water storage tank 31. The heat stored in the hot water storage tank 31 is supplied and consumed for heat demand such as hot water supply and heating outside the system. In addition, when the heat generated in the fuel cell 20 is stored in the hot water storage tank 31, it is not necessary to pass through the heat exchanger 33, but by providing the heat exchanger 33, water quality management of the cooling water c becomes easy.

  By the way, if the operation of the fuel cell power generation system 1 is continued for a long time, the catalytic activity of the air electrode 22 and the fuel electrode 21 of the fuel cell 20 and the catalytic activity of the selective oxidation unit 16 of the fuel processing device 10 are reduced. It is empirically recognized that When the performance of the fuel cell 20 and the fuel processing apparatus 10 is lowered, the operation is performed with low efficiency, which is uneconomical. In order to avoid such inconvenience, the fuel cell power generation system 1 is controlled by the control device 40 as follows.

  During the operation of the fuel cell power generation system 1, the control device 40 determines the cell voltage based on the generated voltage signal transmitted from the cell voltage detector 24 and the voltmeter 25 and the generated current signal transmitted from the ammeter 26. It is determined whether or not the lowest one of them is equal to or lower than the first predetermined value, or whether the power generation voltage of the fuel cell 20 is equal to or lower than the second predetermined value (S204). If the lowest cell voltage is larger than the first predetermined value or if the power generation voltage of the fuel cell 20 is larger than the second predetermined value, the fuel gas g and the oxidant gas a1 to the fuel cell 20 are supplied. The introduction is continued (S202). If the lowest cell voltage is equal to or lower than the first predetermined value or the power generation voltage of the fuel cell 20 is equal to or lower than the second predetermined value, the hot water storage is performed based on the signal transmitted from the heat storage amount detector 32. It is determined whether the amount of heat stored in the tank 31 is equal to or greater than a predetermined amount of heat (S205). If the heat storage amount is less than the predetermined heat amount, introduction of the fuel gas g and the oxidant gas a1 into the fuel cell 20 is continued (S202). If the heat storage amount is equal to or greater than the predetermined heat amount, it is determined based on the signal transmitted from the power conditioner 28 whether the power consumption at the external power load is equal to or less than the predetermined power (S206). If the power consumption is greater than the predetermined power, the fuel gas g and the oxidant gas a1 are continuously introduced into the fuel cell 20 (S202). If the power consumption is less than or equal to the predetermined power, the process proceeds to the next step (S207).

  If the power consumption is less than or equal to a predetermined value, the power generated by the fuel cell 20 is reduced by reducing the current (S207). In order to reduce the current, the fuel gas control valve 42, the oxidant gas control valve 44, the oxygen-containing gas control valve 19, and the reforming water control valve 17 are controlled so that the fuel has a temperature sufficient to generate the fuel gas g. While maintaining the temperature of the processing apparatus 10, the amount of fuel gas g, oxidant gas a 1, oxygen-containing gas a 2, and reforming water s introduced into the fuel cell power generation system 1 is reduced. The generated power is reduced to a state where the current is reduced to cover the power of the auxiliary machines in the fuel cell power generation system 1.

  After the generated power is lowered, the introduction of the fuel gas g or the oxidant gas a1 to the fuel cell 20 is stopped, and the decrease in the electrode catalyst activity of the fuel cell 20 is suppressed. The frequency at which the decrease of the catalyst occurs is not the same as the frequency at which the catalytic activity of the fuel electrode 21 decreases. In the present invention, in consideration of the frequency of occurrence of both, the introduction / stop of the fuel gas g to the fuel electrode 21 is performed once while the introduction of the oxidant gas a1 to the air electrode 22 is stopped three times. Here, it is determined whether or not the value of the symbol N used for convenience to determine which of the fuel gas g and the oxidant gas a1 is to be stopped is 3 or less (S208). First, the case where the value of N is 3 or less will be described. The value of N corresponds to “a predetermined number of times”.

  When the value of N is 3 or less, a value obtained by adding 1 to the value of N at that time is newly set as N (S230). After this, only the power of the auxiliary machine that consumes minute electric power among the auxiliary machines in the fuel cell system 1 is covered by the fuel cell 20, and the power of the other auxiliary machines is supplied from the system power outside the fuel cell power generation system 1. State. Alternatively, all the power of the auxiliary machinery is supplied from the system power, and a resistance for voltage drop (not shown) is provided in the power conditioner 28 in advance, and the fuel cell 20 is installed in the cables 29a and 29b and the power conditioner 28. May be connected to a resistor (not shown) for voltage drop (S231).

  Next, the oxidant gas control valve 44 and the cathode off-gas on / off valve 45 are fully closed (S232), and the introduction of the oxidant gas a1 to the air electrode 22 of the fuel cell 20 is stopped (S233). At this time, the introduction of the fuel gas g to the fuel electrode 21 is continued. As a result, the oxygen concentration in the air electrode 22 is reduced, and the voltage remaining in the fuel cell 20 is lowered by the power of the auxiliary machine that consumes minute power or by a voltage drop resistor (not shown) (S234). ), The power generation of the fuel cell 20 is stopped. Thereafter, the fuel gas g continues to flow through the fuel electrode 21 until the second predetermined time elapses (S235). Thereby, the fuel gas g diffuses and moves little by little from the fuel electrode 21 to the air electrode 22 to restore the catalytic activity of the air electrode 22. In this way, the performance of the fuel cell 20 is restored. The second predetermined time is a time required until the catalytic activity of the air electrode 22 is restored. When the second predetermined time has elapsed (S235), the oxidant gas control valve 44 and the cathode offgas on / off valve 45 are opened (S236), and the introduction of the oxidant gas a1 into the fuel cell 20 is resumed (S202). The power generation is resumed (S203).

  Next, a case where the value of N is not 3 or less will be described. In this case, the value of N is set to 0 (S250). Thereafter, the current value is completely set to 0 in a state where the power of the auxiliary machinery is covered by the system power. Next, the bypass control valve 41 is opened and the fuel gas control valve 42 and the anode off-gas on / off valve 43 are closed (S251). At this time, the oxidant gas control valve 44 is opened to permit the introduction of the oxidant gas a1, and the temperature of the fuel cell 20 decreases due to the stop of the introduction of the fuel gas g to the fuel cell 20, and the air electrode 22 becomes negative pressure. Is prevented. By closing the fuel gas control valve 42 and the anode off-gas on / off valve 43, the introduction of the fuel gas g into the fuel cell 20 is stopped (S252). The fuel gas g whose introduction into the fuel cell 20 is stopped is directly introduced into the combustion unit 11 of the fuel processing apparatus 10 through the bypass passage 54. In the fuel processing apparatus 10, the generation of the fuel gas g is continued. Next, the oxygen-containing gas control valve 19 is closed and the introduction of the oxygen-containing gas a2 to the selective oxidation unit 16 is stopped (S253). The catalytic activity of the catalyst filled in the selective oxidation unit 16 is restored by the continuously generated transformed gas h, and the performance of the fuel processing apparatus 10 is restored. Here, the generated gas is the modified gas h because the introduction of the oxygen-containing gas a2 to the selective oxidation unit 16 is stopped, so that the selective oxidation reaction is not performed and the fuel gas g is not generated. is there. Note that even if the modified gas h containing carbon monoxide is generated here, it is not introduced into the fuel electrode 21, so that the problem of poisoning of the electrode catalyst of the fuel electrode 21 does not occur.

  When the introduction of the fuel gas g to the fuel electrode 21 is stopped (S252), the power generation of the fuel cell 20 is stopped. Thereafter, the state is maintained until the second predetermined time has elapsed (S254). Until the second predetermined time elapses, the oxidant gas a1 entering the air electrode 22 by natural diffusion gradually moves from the air electrode 22 to the fuel electrode 21 by diffusion, and the oxidant gas a1 The catalytic activity of the fuel electrode 21 is restored by the oxygen molecules, and the performance of the fuel cell 20 is restored. Note that the second predetermined time in this case is a time required until the catalytic activity of the fuel electrode 21 is restored.

  When the second predetermined time has elapsed (S254), the oxidant gas control valve 44 and the cathode offgas on / off valve 45 are closed (S255). Thereafter, when the third predetermined time has elapsed (S256), the oxygen-containing gas control valve 19 is opened (S257). Subsequently, the fuel gas control valve 42 and the anode off-gas on / off valve 43 are opened, the bypass control valve 41 is closed (S258), and the introduction of the fuel gas g into the fuel cell 20 is resumed. Thereafter, the oxidant gas control valve 44 and the cathode off-gas on / off valve 45 are opened (S259), the introduction of the oxidant gas a1 is resumed (S202), and power generation is resumed (S203).

  Here, during the period from when the introduction of the fuel gas g to the fuel cell 20 is stopped until it is restarted, the state of supplying the raw material fuel m to the fuel processing device 10 is maintained and the selective oxidation catalyst is restored. Since the processing apparatus 10 does not cool, the heat used for preheating when starting the fuel processing apparatus 10 can be saved. This is not intended to prevent the fuel processing apparatus 10 from being stopped when there is no heat demand or power load outside the system for a long time. Further, when the power generation of the fuel cell 20 is resumed, the fuel electrode g is first introduced into the fuel electrode 21 of the fuel cell 20 and the oxidant gas a1 is then introduced into the air electrode 22 so that the air electrode 22 The high potential is prevented instantaneously and the deterioration of the electrode is prevented.

  In the flowchart of FIG. 3, it is determined whether or not the lowest cell voltage is equal to or lower than a first predetermined value, or whether the power generation voltage of the fuel cell 20 is equal to or lower than a second predetermined value (S204). Alternatively, the accumulated time generated by the fuel cell 20 may be measured based on the signal transmitted from the ammeter 26 to determine whether the accumulated time has reached the first predetermined time. . In this case, when the accumulated time does not reach the first predetermined time, the introduction of the fuel gas g and the oxidant gas a1 into the fuel cell 20 is continued (S202). When the accumulated time reaches the first predetermined time, the process proceeds to a step of determining whether or not the heat storage amount in the hot water storage tank 31 is equal to or greater than the predetermined heat amount (S205). Note that the first predetermined time is a time within a range in which the deterioration of the performance of the fuel cell 20 and the fuel processing device 10 is permissible, which is grasped from experience when the fuel cell power generation system 1 is continuously operated. Further, the measurement of the accumulated time is reset every time the power generation of the fuel cell 20 is stopped by stopping the introduction of the oxidant gas a1 or the fuel gas g to the fuel cell 20.

  In the flowchart of FIG. 3, the determination of the amount of heat stored in the hot water storage tank 31 (S205) and the determination of the power consumption of the external power load (S206) are not the situation at the time of determination, but the past stored in the control device 40. The situation may be predicted based on fluctuations in the amount of stored heat and power consumption. At this time, the fuel cell power generation system 1 may be operated so that the heat storage amount becomes equal to or greater than the predetermined heat amount in accordance with the time period when the power consumption is equal to or less than the predetermined power.

  In the above description, the carbon monoxide reduction unit 14 has been described as having the shift conversion unit 15 and the selective oxidation unit 16 (paragraph 0027). However, the carbon monoxide reduction unit 14 in the mixed gas r to the extent that the catalyst of the fuel cell 20 is not poisoned with sulfur. When carbon monoxide can be reduced, the metamorphic portion 15 may not be provided. In that case, the mixed gas r is directly introduced into the selective oxidation unit 16.

  In the above description, the fuel cell 20 has been described as a polymer electrolyte fuel cell, but it may be a fuel cell other than a polymer electrolyte fuel cell such as a phosphoric acid fuel cell.

  In the above description, it has been determined whether the introduction of the fuel gas g or the oxidant gas a1 is stopped depending on whether the value of N is 3 or more (paragraph 0053), depending on the characteristics of the fuel cell used. A value other than 3 may be used.

  Further, it has been described that the introduction of the oxidant gas a1 to the air electrode 22 is stopped more than the introduction and stop of the fuel gas g to the fuel electrode 21 (paragraph 0053). There may be more cases where the introduction of the fuel gas g to the fuel electrode 21 is stopped than the introduction of the oxidant gas a1 is stopped. In this case, in the flowchart of FIG. 3, step S230 is N = 0, and step S250 is N = N + 1.

1 is a schematic system diagram illustrating a fuel cell power generation system according to an embodiment of the present invention. It is a graph which shows the relationship between the electric power generation electric current and electric power generation voltage of a fuel cell. It is a flowchart explaining operation | movement of the fuel cell power generation system which concerns on embodiment of this invention. It is a figure which shows the state of each control valve of the fuel cell power generation system which concerns on embodiment of this invention for every process in the flowchart of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fuel cell power generation system 10 Fuel processing apparatus 11 Combustion part 13 Reforming part 14 Carbon monoxide reduction part 20 Fuel cell 21 Fuel electrode 22 Air electrode 24 Cell voltage measuring device (voltage measuring means)
25 Voltmeter (Voltage measuring means)
28 Power conditioner (external power load detection means)
31 Hot water storage tank 32 Heat storage amount detector (heat storage amount detection means)
40 control device a1 oxidant gas a2 oxygen-containing gas g fuel gas m raw material fuel r mixed gas

Claims (7)

A fuel electrode for introducing a fuel gas rich in hydrogen and an air electrode for introducing an oxidant gas containing oxygen, and generating electric power by an electrochemical reaction between hydrogen in the fuel gas and oxygen in the oxidant gas And a fuel cell to do;
Voltage measuring means for measuring the generated voltage;
When the measured voltage falls below a predetermined value, the fuel cell power generation is stopped by stopping the introduction of the oxidant gas to the air electrode while continuing the introduction of the fuel gas to the fuel electrode. A control device for
Fuel cell power generation system. A fuel electrode for introducing a fuel gas rich in hydrogen and an air electrode for introducing an oxidant gas containing oxygen, and generating electric power by an electrochemical reaction between hydrogen in the fuel gas and oxygen in the oxidant gas And a fuel cell to do;
The accumulated time generated by the fuel cell is measured, and when the accumulated time reaches a first predetermined time, the oxidant gas to the air electrode is continuously introduced while the fuel gas is being introduced to the fuel electrode. A control device that stops the power generation of the fuel cell by stopping the introduction of the fuel cell;
Fuel cell power generation system. The control device performs the control for stopping the introduction of the oxidant gas to the air electrode while continuing the introduction of the fuel gas to the fuel electrode, while allowing the introduction of oxygen to the air electrode. Performing control to stop power generation of the fuel cell by stopping introduction of fuel gas to the fuel electrode;
The fuel cell power generation system according to claim 1 or 2. A hot water storage tank for storing heat generated in the fuel cell using water as a medium;
A heat storage amount detecting means for detecting a heat storage amount stored in the hot water storage tank;
An external power load detecting means for detecting power supplied to an external power load among the power generated by the fuel cell;
In addition to the condition for stopping the power generation of the fuel cell, the heat storage amount detected by the heat storage amount detection means is equal to or greater than a predetermined heat amount, and the power consumption detected by the external power load detection means is equal to or less than the predetermined power. And a controller for stopping power generation in the fuel cell;
The fuel cell power generation system according to any one of claims 1 to 3. A hot water storage tank for storing heat generated in the fuel cell using water as a medium;
A heat storage amount detecting means for detecting a heat storage amount stored in the hot water storage tank;
An external power load detecting means for detecting power supplied to an external power load among the power generated by the fuel cell;
Based on the heat storage amount detected by the heat storage amount detection means, the fluctuation of the heat storage amount of the day is recorded, and the power consumption of the day is recorded based on the power consumption detected by the external power load detection means. Recording the fluctuation, and based on the record of the heat storage amount and the power consumption, the fuel is stored in the time zone in which the heat storage amount is expected to be equal to or greater than the predetermined heat amount and the power consumption is equal to or less than the predetermined power within a day. A control device that stops power generation in the fuel cell when conditions for stopping power generation of the battery are provided;
The fuel cell power generation system according to any one of claims 1 to 3. The control device resumes power generation of the fuel cell after a second predetermined time has elapsed after stopping of power generation of the fuel cell;
The fuel cell power generation system according to any one of claims 1 to 5. A reforming section that introduces and reforms a raw material fuel to generate a mixed gas containing hydrogen and carbon monoxide; a combustion section that supplies heat necessary for the reforming to the reforming section; and an oxygen-containing gas; A fuel processing apparatus having a carbon monoxide reducing unit that introduces the mixed gas to reduce carbon monoxide in the mixed gas and generates the fuel gas;
When the introduction of the fuel gas to the fuel electrode is stopped, the fuel gas generated by the fuel processing device is introduced into the combustion part, bypassing the fuel electrode, and oxygen to the carbon monoxide reduction part A control device for controlling to stop the introduction of the contained gas;
The fuel cell power generation system according to any one of claims 1 to 6.

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