JP2006310109A - Fuel cell power generating system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To appropriately cancel abnormality, corresponding to an abnormal cause by properly determining the abnormal cause of a fuel cell power generation system. <P>SOLUTION: If voltage reduction of a fuel cell is voltage reduction of the cell (S3) as a whole, when a physical quantity correlated to an anode gas flow rate is less than a set value (S4), the voltage reduction of the fuel cell is determined to be caused by the lack of the amount of hydrogen (S5), when the physical quantity correlated to the anode gas flow rate is larger than the set value (S4); and when the anode gas temperature is lower than the set value, it is determined to be caused by the lack of humidification of reformed gas (S8, S9), when the anode gas temperature is higher than the set value, it is determined to be caused by CO poisoning (S8, S12). In any of the cases, the load current of the fuel cell is reduced (S6-S13) and a command for increasing the amount of hydrogen of the reformed gas corresponding to each cause (S7), a command for raising the anode gas temperature (S11) or a command for reducing the CO concentration of the reformed gas (S14) is outputted. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a fuel cell power generation system including a hydrogen production apparatus and a fuel cell. Specifically, the present invention relates to a stable operation of a fuel cell power generation system by suppressing voltage fluctuations in a polymer electrolyte fuel cell. Regarding technology.

  Since the fuel cell power generation system has high overall efficiency, a small-scale polymer electrolyte fuel cell power generation system for general households has been proposed as one of the home cogeneration systems that can save energy. . In such a household fuel cell power generation system, for example, it is considered to supply hot water by generating heat using heat generated during power generation while supplying generated power connected to a power system of an electric power company. . In order to popularize the fuel cell power generation system for home use, in addition to improving the performance of the entire system, reducing the size and weight, mass production, and reducing the cost, it is possible to maintain stable operation without requiring maintenance and inspection as much as possible. A system is desired.

  In general, an abnormality that prevents stable operation of the fuel cell power generation system appears as a drop in the voltage of the fuel cell. Therefore, it is conceivable to detect and respond to the abnormality of the fuel cell power generation system based on the voltage drop of the fuel cell. . For example, in Patent Document 1, when the voltage drop of the fuel cell is caused by the voltage drop of some of the cells of the fuel cell, it is determined that some of the cells are flooded (water clogging), It has been proposed to purge the gas in the fuel cell to discharge the clogged water. In Patent Document 2, the time differential value of the voltage change of the fuel cell is taken, and if the absolute value is large, it is determined as flooding, the gas supply amount is increased, or the cooling water flow rate is decreased to increase the gas temperature. It has been proposed to eliminate flooding. In addition, the gas purge method for eliminating flooding is to increase the flow rate of gas by increasing the gas flow rate and gas pressure, or by reducing the load of the fuel cell to suppress the hydrogen consumption in the fuel cell (Patent Document 3).

  On the other hand, Patent Document 4 mentions that the fuel cell electrodes and the like are poisoned by carbon monoxide (CO) as a cause of the voltage drop of the fuel cell.

JP 2003-031242 A JP 2001-148253 A JP 2003-217622 A JP 2000-48845 A

  However, abnormalities such as a decrease in battery voltage in a fuel cell power generation system including a hydrogen production apparatus and a fuel cell are not limited to flooding or CO poisoning, but can be caused by various causes. In 1-4, it is not considered about comprehensively determining the cause of the abnormality. For example, in a fuel cell power generation system in which reformed gas as a fuel is supplied from a hydrogen production device to an anode of a polymer electrolyte fuel cell stack and an oxidant gas is supplied to a cathode to generate power, the cause of the voltage drop is fuel It is often in the system of hydrogen production equipment, not the battery stack. Therefore, in order to eliminate the abnormality and stably control the operation of the fuel cell power generation system, the cause of the abnormality is determined based on the behavior of the fuel cell stack that is the source of the event of power generation, and the hydrogen production apparatus It is necessary to control the behavior of the problem and eliminate the abnormality. In particular, it is necessary to construct a fuel cell power generation system so that both the hydrogen production apparatus and the fuel cell can continue to operate stably by taking appropriate measures in response to the cause of the abnormality.

  Accordingly, an object of the present invention is to accurately determine the cause of abnormality of the fuel cell power generation system.

  Another object of the present invention is to appropriately solve an abnormality in response to the cause of the abnormality, and to enable stable operation of both the hydrogen production apparatus and the fuel cell.

  In order to solve the above problems, the present invention provides a fuel cell in which a plurality of polymer electrolyte cells are stacked, a hydrogen production apparatus for supplying a reformed gas containing hydrogen to the anode of the fuel cell, and the fuel cell. In the fuel cell power generation system comprising a supply device for supplying an oxidant gas containing oxygen to the cathode of the fuel cell and a control device having an abnormality cause determination means upon occurrence of a voltage drop in the fuel cell, the abnormality cause determination means includes: When the voltage drop of the fuel cell is a voltage drop of the entire cell, and the physical quantity correlated with the anode gas flow rate is less than a set value, the amount of hydrogen that is judged to be caused by an insufficient hydrogen amount An abnormality determining means is provided.

  That is, when the voltage drop of the fuel cell is caused by the voltage drop of some cells, it is caused by flooding. However, if the cell voltage is decreased overall, it is due to a cause other than flooding. The cause is insufficient hydrogen, insufficient reformed gas humidification, or CO poisoning of the fuel cell. Therefore, it is necessary to distinguish the causes.

  Therefore, when the shortage of hydrogen is the cause, the physical quantity correlated with the anode gas flow rate (for example, inlet gas pressure) should have decreased, so the physical quantity correlated with the anode gas flow rate is compared with the set value. When the value is less than the set value, it can be determined that the shortage of the hydrogen amount is the cause. When it is determined that the shortage of hydrogen is the cause, the load current of the fuel cell is decreased, and a command for increasing the hydrogen amount of the reformed gas is output to the hydrogen production apparatus. Here, the reason for reducing the load current is that there is a risk of degrading the electrode and electrolyte membrane of the fuel cell if the load current is maintained at the value at that time even though the voltage drop has occurred due to the lack of hydrogen. It is. The amount of decrease in load current is set to a preset amount (for example, 2A). The command for increasing the hydrogen amount of the reformed gas can be, for example, a command for adjusting the reforming catalyst temperature of the reformer. Specifically, it can be based on a command for adjusting the amount of air input to the reformer or the amount of water input, or the amount of cooling water in the reformer.

  In this way, when the amount of hydrogen supplied to the anode increases to the set value, the load current of the fuel cell is returned to the original value. Thereby, the abnormal state of the fuel cell system can be resolved and the operation can be continued stably.

  On the other hand, when the voltage drop of the fuel cell is the voltage drop of the entire cell and the physical quantity correlated with the anode gas flow rate is equal to or larger than the set value, the hydrogen amount is not insufficient. In this case, when the anode gas temperature is detected and the detected temperature is lower than the set value, it can be determined that the fuel cell voltage drop is caused by insufficient humidification of the reformed gas. In addition, when the fuel cell voltage drop is caused by insufficient humidification, the load current of the fuel cell is reduced, and a command to raise the temperature of the reformed gas is output to the hydrogen production device to eliminate insufficient humidification. To do.

  Here, the reason why the load current is decreased is the same reason as in the case of the above-mentioned hydrogen shortage. In addition, the command to raise the temperature of the reformed gas can be a command to turn on the heater when a heater is provided in the fuel cell or the reformed gas pipe. Alternatively, or in addition to this, a command for reducing the heat recovery amount of the heat exchanger provided between the hydrogen production apparatus and the fuel cell can be used. In this way, when the gas temperature at the anode inlet is restored to the set value, the load current of the fuel cell is restored to the original value. Thereby, the abnormal state of the fuel cell system can be resolved and the operation can be continued stably.

  Further, when the voltage drop of the fuel cell is the voltage drop of the entire cell, the physical quantity correlated with the anode gas flow rate is equal to or higher than the set value, and the anode gas temperature is equal to or higher than the set value, the voltage drop of the fuel cell It can be determined that poison is the cause. And when the voltage drop of the fuel cell is caused by CO poisoning, the load current of the fuel cell is reduced and the CO poisoning is eliminated by outputting a command to reduce the CO concentration to the hydrogen production device. Can do.

  Here, the load current is decreased for the same reason as in the case of the above-mentioned hydrogen shortage, but is further adhered to the inside by reducing the hydrogen consumption and increasing the gas flow rate in the fuel cell. This is for purging CO. Further, the command for reducing the CO concentration is a command for adjusting the CO shift catalyst temperature and / or the CO selective oxidation catalyst temperature of the hydrogen production apparatus in a direction in which the CO concentration in the reformed gas decreases. In this way, when the CO concentration in the reformed gas decreases to the set value, the load current of the fuel cell is returned to the original value. Thereby, the abnormal state of the fuel cell system can be resolved and the operation can be continued stably.

  According to the present invention, the cause of abnormality of the fuel cell power generation system can be accurately determined.

  Further, the abnormality can be appropriately resolved in response to the cause of the abnormality, and the operation of both the hydrogen production apparatus and the fuel cell can be continued stably.

  Hereinafter, a fuel cell power generation system of the present invention will be described based on embodiments.

  FIG. 1 shows the overall configuration of the fuel cell power generation system of the present invention. The fuel cell 1 is configured as a fuel cell stack in which a plurality of cells (for example, 80 cells) are stacked. Each cell is provided with an anode and a cathode with a polymer electrolyte membrane interposed therebetween, and these cells are connected in series. The anode and cathode of each cell are in communication with an anode chamber to which a hydrogen-rich reformed gas is supplied and a cathode chamber to which oxygen-containing air is supplied.

  The hydrogen production apparatus 2 produces a hydrogen-rich reformed gas using hydrogen-containing fuel such as hydrocarbons, alcohols, ethers, etc., oxygen or air, and water or steam as raw materials. As is well known, the reformer is configured to have a reforming reactor, a CO converter for removing CO in the reformed gas, and a CO selective oxidizer. In the reforming reactor, a reforming catalyst layer and a combustion catalyst layer for partial combustion for supplementing the heat of the endothermic reaction of the reforming reaction are provided upstream of the reforming catalyst layer. The CO converter is provided with a CO shift catalyst layer that removes CO in the reformed gas generated in the reforming reactor, and the CO selective oxidizer removes a small amount of CO in the reformed gas discharged from the CO converter. A selective oxidation catalyst layer for oxidation is provided. The reformed gas discharged from the CO selective oxidizer is supplied to the anode gas inlet 1 a of the fuel cell 1 through the fuel pipe 3. An anode gas inlet pressure measuring device 4 for measuring the pressure of the reformed gas and an anode gas inlet temperature measuring device 5 for measuring the temperature of the reformed gas are provided at the anode gas inlet.

  On the other hand, for example, air is supplied as an oxidant gas from the blower 6 to the cathode gas inlet 1 b provided in the cathode chamber of the fuel cell 1. The anode and cathode of the fuel cell 1 are connected to an inverter 7, and the inverter 7 converts DC power generated by the fuel cell 1 into a predetermined AC and supplies it to a load 8. The reformed gas exhaust gas contributing to the power generation reaction of the fuel cell 1 is discharged from the anode exhaust gas pipe 9 as anode exhaust gas. Further, the exhaust of air that has contributed to the power generation reaction of the fuel cell 1 is discharged from the cathode exhaust pipe 10 as cathode exhaust gas. In addition, circulating water for heating or cooling the fuel cell 1 is circulated from the water circulation device 11 to the fuel cell 1. The temperature of the circulating water can be adjusted by the circulating water heater 12. Furthermore, the fuel cell 1 is provided with a cell voltage measuring device 13 that measures a generated voltage in units of cells or in groups of a plurality of cells. The inverter 7 is provided with a load current measuring device 14 that measures the load current.

  The control device 15 controls the entire fuel cell system by controlling the hydrogen production device 2, the blower 6, the inverter 7, the water circulation device 11, the circulation water heater 12, and the like. In particular, in the present embodiment, the abnormality of the fuel cell system is determined based on the measurement values input from the anode gas inlet pressure measuring device 4, the anode gas inlet temperature measuring device 5, the cell voltage measuring device 13, the load current measuring device 14, and the like. Is detected, and control to eliminate the abnormality is performed.

  Here, an outline of the operation of the fuel cell system configured as shown in FIG. 1 will be described. A hydrogen-rich reformed gas adjusted to a predetermined temperature and humidity is supplied from the hydrogen production apparatus 2 to the anode gas inlet 1a, and air is supplied from the blower 6 to the cathode gas inlet 1b. As a result, power generation by an electrochemical reaction occurs in the fuel cell 1, and the generated power is supplied to the load 8 via the inverter 7. The temperature in the fuel cell 1 is measured by a cooling water temperature measuring device 16 provided at the circulating water outlet of the fuel cell 1 and input to the control device 15. The control device 15 controls the amount and temperature of the circulating water circulated from the water circulation device 9 so as to keep the measured temperature of the cooling water temperature measuring device 16 at the set temperature. Further, the temperature of the circulating cooling water is controlled by the circulating water heater 12. The control device 15 basically has a hydrogen production device 2, a blower 6, an inverter 7, a water circulation device 11, a circulating water heater so as to keep the generated power of the fuel cell 1 at a predetermined value (for example, a rated value). 12, etc., to control the entire fuel cell system.

  Next, a detailed configuration of the abnormality cause determining means for accurately determining the cause of abnormality of the fuel cell power generation system, which is a feature of the present invention, and the control device 15 relating to each means for appropriately eliminating the abnormality corresponding to the cause of the abnormality The operation will be described. FIG. 2 shows a flowchart of an embodiment of a control procedure for determining an abnormality cause and eliminating the abnormality.

  As shown in FIG. 2, the control device 15 reads measured values of the anode gas inlet pressure measuring device 4, the anode gas inlet temperature measuring device 5, the cell voltage measuring device 13, the load current measuring device 14, and the like (S1). Next, based on the measured value of the cell voltage measuring device 13, it is determined whether or not the cell voltage of the fuel cell 1 is lower than the reference range (S2). This determination can be made based on the power generation output voltage of the fuel cell 1 that is the total voltage of the plurality of cells. If the power generation output voltage (or the voltage of each cell) is within the reference range, it is determined that there is no abnormality, the process returns to step S1, and the process of the flowchart of FIG. 2 is repeated. On the other hand, when the power generation output voltage is lower than the reference range, the process proceeds to step S3 to determine whether the cause of the cell voltage drop is due to flooding or an event other than flooding. Here, a detailed configuration of the cell voltage measuring device 13 is shown in FIG. As shown in the figure, the cell voltage measuring device 13 has terminals connected to the anode 21 and the cathode 22 of each cell 20, measures the voltage in units of each cell, and the voltage of the entire cell stack (power generation output voltage). Is configured to be measurable. Further, the anode and cathode at both ends of the cell 20 connected in series are connected to the input terminal of the inverter 7.

  For reference, FIG. 4 shows the current value (A) and average voltage characteristics of each cell. As shown in the figure, the cell voltage gradually decreases as the current increases. In the figure, line 25 is a normal cell average voltage (initial value) when normal, line 26 is a decrease determination value (reference cell voltage) for determining a voltage drop for some reason, and line 27 is a stop determination value for stopping power generation. Show. The average cell voltage is a value obtained by dividing the power generation voltage of the fuel cell 1 by the number of cells.

(If it is caused by flooding)
A drop in cell voltage due to flooding usually appears as a drop in the voltage of some cells over time as shown in FIG. In cases other than flooding, as shown in FIG. 6, all the cell voltages are unstablely lowered with the elapsed time. Therefore, in the determination of step S3, the ratio of the number of cells in which the difference between the voltage of some cells and the reference cell voltage is lower than the allowable range is examined, and some cell voltages are reduced. If it is, it is determined that the flow path blockage due to flooding is the cause of the voltage drop. On the other hand, when the voltages of the plurality of cells are decreased as a whole, it is determined that the cause of the voltage decrease is due to other than flooding. Note that the decrease in the cell voltage may be determined for each cell voltage, but can also be determined in units of groups or blocks composed of a plurality of cells.

  If the cause of the voltage drop is due to flooding, after outputting that fact in step S15, after outputting a command to reduce the load current to the inverter 7 by a set amount (for example, 2A) (S16), the cooling water ( A command to increase the temperature of the circulating water) is output to the circulating water heater 12 of the water circulation device 11. Here, the reason why the load current is reduced is to prevent the electrode and electrolyte membrane of the fuel cell 1 from deteriorating, reduce the electrode reaction to reduce the amount of water generated, and increase the gas flow rate to clog. This is for purging water. The reason for raising the cooling water temperature is to reduce the amount of condensed water. In this way, the control is maintained until the operating condition of the hydrogen production apparatus 2, that is, the coolant temperature rises to the set value (S18, S19). Then, it is confirmed that the coolant temperature measured by the coolant temperature measuring device 16 has risen to the set value (S18), and the load current is increased to the original value (predetermined value) to return to the original control. Thereby, the abnormal state of the fuel cell system can be resolved and the operation can be continued stably.

(If the cause is a decrease in the amount of hydrogen)
If the result of determination in step S3 is that the voltage drop is determined to be a cause other than flooding, it is determined whether or not the anode gas inlet pressure is lower than the set value (S4). Is determined to be the cause, and a message to that effect is output (S5). Then, after outputting a command to decrease the load current to the inverter 7 by a set amount (for example, 2A) (S6), an instruction to increase the hydrogen amount is output to the hydrogen production apparatus 2. Here, the reason why the load current is reduced is that if the voltage drop occurs due to a hydrogen shortage (anode gas deficiency state) and the load current is maintained at the current value, the electrode of the fuel cell or the electrolyte membrane This is because it may deteriorate. A command to increase the amount of hydrogen is, for example, a command to adjust the reforming catalyst temperature of the reformer, specifically, an amount of input air or water content to the reformer, or a cooling water amount of the reformer. Depending on the order to In this way, the control is maintained until the operating condition of the hydrogen production apparatus 2 rises to a value according to the command and the anode gas inlet pressure recovers to the set value (S18, S19). Then, after confirming that the anode gas inlet pressure has been restored to the set value (S18), the load current is increased to the original value (predetermined value) and returned to the original control. Thereby, the abnormal state of the fuel cell system can be resolved and the operation can be continued stably.

(If the cause is insufficient humidification of the reformed gas)
If it is determined in step S4 that the anode gas inlet gas pressure is not lower than the set value, the decrease in the hydrogen amount is not the cause of the voltage drop. Therefore, the process proceeds to step S8 to check whether the anode gas inlet temperature is lower than the set value. to decide. If the anode gas inlet temperature is lower than the set value, it is determined that the reformed gas is insufficiently humidified, and a message to that effect is output (S9). Then, after outputting a command to reduce the load current to the inverter 7 by a set amount (for example, 2A) (S10), a command to increase the anode gas inlet temperature, which is the reformed gas, is output to the hydrogen production device 2 (S11). Increase the anode dew point. Here, the reason why the load current is decreased is to suppress the gas permeation deficiency due to insufficient humidification and to prevent the deterioration of the electrodes and the electrolyte membrane of the fuel cell. When the heater is provided in the fuel cell 1 or the reformed gas fuel pipe 3, the command to raise the temperature of the reformed gas can be a command to turn on the heater. Or it can be set as the instruction | command which reduces the heat recovery amount of the heat exchanger provided between the hydrogen production apparatus 2 and the fuel cell 1 instead of this or with this. Thus, when the anode inlet gas temperature is restored to the set value (S18, S19), the load current is returned to the original value (S20). Thereby, the abnormal state of the fuel cell system can be resolved and the operation can be continued stably.

(If it is caused by CO poisoning)
If it is determined in step S8 that the anode gas inlet temperature is not lower than the set value, the cause of the voltage drop is not due to insufficient humidification, but is considered to be CO poisoning of the fuel cell 1, and this is output. (S12). FIG. 7 shows an example of the temporal change of the cell voltage with respect to the CO concentration in the reformed gas when the cell voltage decreases due to CO poisoning. From this voltage change tendency, an approximate value of the CO concentration in the reformed gas can be grasped without using a CO monitor. Then, the process proceeds to step S13, and a command to reduce the load current by a set amount (for example, 2A) is output to the inverter 7 (S13), and a command to reduce the concentration of carbon monoxide (CO) is output to the hydrogen production apparatus 2. (S14). Here, the purpose of reducing the load current is to prevent power generation in a state where the ionization ability of hydrogen is reduced at the anode due to the primary poisoning of platinum. Further, when the reformed gas reaches the anode with CO mixed therein, carbon monoxide poisoning occurs in the catalyst in the anode, and the ionization reaction of hydrogen is inhibited. Therefore, the CO concentration in the reformed gas is reduced to prevent carbon monoxide from being mixed into the anode, and CO already attached to the anode is discharged to restore the power generation environment. In order to reduce the CO concentration in the reformed gas, it is possible to increase the amount of air injected into the CO selective oxidizer or increase the amount of raw material gas supplied to the hydrogen production apparatus 2. Alternatively, the CO shift catalyst temperature is adjusted, or the CO selective oxidation catalyst temperature is adjusted. In addition, the normal CO shift catalyst temperature and the CO selective oxidation catalyst temperature can be set to, for example, 250 to 350 ° C. and 120 to 180 ° C., respectively. As described above, the determination of steps S4, S8, and S12 makes it possible to determine the CO poisoning without measuring the CO concentration with an expensive CO monitor as in the prior art. In this way, when the CO concentration is restored to the set value (S18, S19), the load current is returned to the original value (S20). Thereby, the abnormal state of the fuel cell system can be resolved and the operation can be continued stably.

(Other embodiments)
In the embodiment of FIG. 2, regardless of the cause of the voltage drop described above, the recovery determination in step S18 is that the generated voltage measured by the cell voltage meter 13 has risen within the allowable range of the reference voltage. It may be judged by the fact that the power generation voltage has shifted to an upward trend.

  In step S4, determining that the cause of the voltage decrease due to the decrease in the anode gas inlet pressure is a decrease in the amount of hydrogen means that the amount of hydrogen-rich reformed gas flowing into the fuel cell 1 is small. Therefore, instead of a decrease in the anode gas inlet pressure, a decrease in the anode gas flow rate, a decrease in the anode gas outlet pressure, which is a physical quantity correlated with the anode gas flow rate, or a decrease in the differential pressure between the anode gas inlet pressure and the outlet pressure, It can be judged that the amount is reduced.

  Further, when the amount of the hydrogen-rich reformed gas supplied to the anode chamber decreases, the oxygen consumption of the air supplied to the cathode chamber decreases, so that the cathode gas inlet pressure increases. Therefore, instead of lowering the anode gas inlet pressure, the determination object in step S4 is when the cathode gas outlet pressure or the differential pressure between the cathode gas inlet pressure and the outlet pressure, which is a physical quantity correlated with the cathode gas flow rate, is increased. It can be determined that the amount of hydrogen is reduced.

  Further, in step S8, insufficient humidification and CO poisoning are distinguished depending on whether or not the anode gas inlet temperature is lower than a set value, but instead of the anode gas inlet temperature, the fuel is a physical quantity that correlates with the anode gas inlet temperature. Insufficient humidification and CO poisoning can be distinguished based on whether or not the anode gas temperature inside the battery 1 is lower than the set allowable value. Further, the difference between the anode gas temperature in the fuel cell 1 and the anode gas inlet temperature is taken, and when this difference is equal to or greater than a set allowable value (for example, 15 ° C.), it is determined that the cause is insufficient humidification. it can.

  Further, in the embodiment of FIG. 2, it is determined that flooding occurs due to a decrease in voltage drop of some cells. Alternatively, it can be determined that the flooding has occurred when the cell voltage drop has a gradient close to vertical. That is, as shown in FIG. 8A, when flooding occurs, the cell voltage decrease gradient shows a large gradient as it is close to vertical. On the other hand, when the voltage decreases due to a cause other than flooding, as shown in FIG. Therefore, based on the cell voltage decrease gradient, it is possible to determine whether the cause of the voltage decrease is due to flooding or not.

  Therefore, in the determination of step S3 in FIG. 2, if the voltage or current drop is nearly vertical, it is determined to be flooding. Otherwise, the cause other than flooding, that is, insufficient hydrogen amount, insufficient humidification, CO poisoning. As a cause, the determinations in steps S4 to S12 can be performed.

  As described above, according to each embodiment of the present invention, the voltage drop due to the variation in cell voltage is due to “flow channel blockage due to flooding”, “decrease in hydrogen amount”, or “insufficient humidification”. It is possible to perform stable operation of the fuel cell power generation system without deteriorating the operation state of the fuel cell 1 and without using an expensive CO monitor by determining whether the fuel cell is due to an increase in CO concentration or not. it can.

It is a system configuration | structure figure of one Embodiment of the fuel cell power generation system of this invention. It is a flowchart of one Embodiment of the control procedure which eliminates abnormality cause determination and abnormality which concern on the characteristic of this invention. It is a figure which shows the detailed structure of the cell voltage measuring device of FIG. It is a figure which shows the electric current value of a cell, and the characteristic of an average voltage. It is a figure which shows the characteristic of the fall with respect to the elapsed time of the cell voltage by flooding. It is a figure which shows the characteristic of the fall with respect to the elapsed time of the cell voltage in cases other than flooding. It is a figure which shows the example of the time change of the cell voltage with respect to CO density | concentration in reformed gas when a cell voltage falls by CO poisoning. The gradient of the cell voltage drop due to flooding is so large that it is nearly vertical as shown in FIG. 9A. When the voltage drops due to a cause other than flooding, the gradient of change is gentle as shown in FIG. It is a figure which shows that it is.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fuel cell 2 Hydrogen production apparatus 4 Anode gas inlet pressure measuring device 5 Anode gas inlet temperature measuring device 6 Blower 7 Inverter 8 Load 11 Water circulating device 12 Circulating water heater 13 Cell voltage measuring device 14 Load current measuring device 15 Control device

Claims (9)

A fuel cell in which a plurality of polymer electrolyte cells are stacked, a hydrogen production apparatus for supplying a reformed gas containing hydrogen to the anode of the fuel cell, and an oxidant gas containing oxygen to the cathode of the fuel cell A fuel cell power generation system comprising: a supply device configured to perform control, and a control device having abnormality cause determination means when a voltage drop occurs in the fuel cell.
The abnormality cause determining means is that when the fuel cell voltage drop is a voltage drop of the entire cell, and the physical quantity correlated with the anode gas flow rate is less than a set value, the fuel cell voltage drop is caused by an insufficient amount of hydrogen. A fuel cell power generation system comprising hydrogen amount abnormality determination means for determining that   The control device outputs a command to decrease the load current of the fuel cell and increase the amount of hydrogen of the reformed gas to the hydrogen production device when the voltage drop of the fuel cell is caused by hydrogen shortage. The fuel cell power generation system according to claim 1.   3. The fuel cell power generation system according to claim 2, wherein when the amount of hydrogen supplied to the anode increases to a set value, the control device returns the load current of the fuel cell to the original value. 4. A fuel cell in which a plurality of polymer electrolyte cells are stacked, a hydrogen production apparatus for supplying a reformed gas containing hydrogen to the anode of the fuel cell, and an oxidant gas containing oxygen to the cathode of the fuel cell A fuel cell power generation system comprising: a supply device configured to perform control, and a control device having abnormality cause determination means when a voltage drop occurs in the fuel cell.
When the fuel cell voltage drop is a voltage drop of the entire cell, the physical quantity correlated with the anode gas flow rate is greater than or equal to a set value, and the anode gas temperature is less than the set value, the abnormality cause determination means A fuel cell power generation system comprising a humidification abnormality determination means for determining that the voltage drop is caused by insufficient humidification of the reformed gas.   When the voltage drop of the fuel cell is caused by insufficient humidification, the control device decreases the load current of the fuel cell and outputs a command to raise the temperature of the reformed gas to the hydrogen production device. The fuel cell power generation system according to claim 4.   6. The fuel cell power generation system according to claim 5, wherein the control device returns the load current of the fuel cell to the original value when the anode gas temperature recovers to a set value. 7. A fuel cell in which a plurality of polymer electrolyte cells are stacked, a hydrogen production apparatus for supplying a reformed gas containing hydrogen to the anode of the fuel cell, and an oxidant gas containing oxygen to the cathode of the fuel cell A fuel cell power generation system comprising: a supply device configured to perform control, and a control device having abnormality cause determination means when a voltage drop occurs in the fuel cell.
When the fuel cell voltage drop is a voltage drop of the entire cell, the physical quantity correlated with the anode gas flow rate is equal to or higher than a set value, and the anode gas temperature is equal to or higher than the set value, A fuel cell power generation system comprising CO poisoning determining means for determining that the voltage drop is caused by CO poisoning.   When the fuel cell voltage drop is caused by CO poisoning, the control device reduces the load current of the fuel cell and outputs a command to reduce the CO concentration to the hydrogen production device. The fuel cell power generation system according to claim 7.   9. The fuel cell power generation system according to claim 8, wherein when the CO concentration decreases to a set value, the control device returns the load current of the fuel cell to the original value.

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