JP2007193952A - Fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell having constitution capable of easily surely removing organic impurities contained in air without newly producing an electrode catalyst poisoning material, increasing air temperature, decreasing a system efficiency, and complicating system constitution. <P>SOLUTION: For example, the fuel cell having constitution by sucking in air around the fuel cell and supplying it with a blower 6 in an air supply system 3 connected to a PEFC stack 1 is equipped with an organic impurity removing device 7 installed in the air supply system 3, making to flow air around the fuel cell sucked with the blower 6, and removing organic impurities contained in the air during flowing by adsorbing with an adsorbent (activated carbon, a plaster coated plate, or adsorbing gel). <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a fuel cell, and more particularly to treatment of air supplied to a main body of a fuel cell such as a polymer electrolyte fuel cell.

  In a polymer electrolyte fuel cell (PEFC), a PEFC stack (fuel cell body) is formed by stacking a plurality of cells each having a solid polymer electrolyte membrane sandwiched between a pair of electrode membranes, and fuel gas is supplied to the PEFC stack. And oxidant gas are supplied to generate electricity by electrochemically reacting these supply gases in each cell of the stack.

  In such a polymer electrolyte fuel cell, in particular, a stationary one, it is common to use air (atmosphere) around the fuel cell as an oxidant gas. That is, air (atmosphere) around the fuel cell is sucked and supplied to the air electrode side of the stack by a blower of an air supply line connected to the PEFC stack. In this case, a dust removal filter is disposed in the air supply line in order to remove dust contained in the sucked air.

  However, air (atmosphere) may contain not only dust but also organic impurities such as xylene, toluene, gasoline, and light oil, and the dust filter cannot remove these organic impurities. Toluene and xylene are used as paint solvents and the like, and may volatilize and be contained in the atmosphere. Gasoline and light oil may also be volatilized and contained in the atmosphere, and it is considered that the concentration of gasoline or light oil contained in the atmosphere is particularly high near the gas station (see FIG. 3: details will be described later). When air containing these organic impurities is supplied to the air electrode side of the PEFC stack, the electrode catalyst on the air electrode side is poisoned by the organic impurities, thereby reducing the power generation performance (power generation voltage) of the PEFC stack. Resulting in.

  For this reason, when the air around the fuel cell is used as the oxidant gas, it is necessary to remove organic impurities contained in the air. Patent Document 1 below discloses a means for removing organic impurities contained in the air.

  The organic impurity removing means disclosed in Patent Document 1 is disposed in the middle of the air supply path so that the temperature of the combustion catalyst layer can be raised by the heat generated by the CO selective oxidation reactor or CO converter of the reformer. Thus, when air flows through the combustion catalyst layer, organic impurities contained in the air are combusted and decomposed to be removed.

Japanese Patent No. 3530413

  However, the conventional organic impurity removing means has the following problems.

(1) When an organic impurity is burnt and decomposed in the combustion catalyst layer, CO that is a poisoning substance of the electrode catalyst may be generated.
(2) Since the air temperature becomes very high when organic impurities are burned and decomposed in the combustion catalyst layer, it is necessary to reduce the air temperature to a temperature suitable for supply to the air electrode.
(3) By using the heat of the reformer for the combustion decomposition of organic impurities, the use for other purposes is limited, so that the system efficiency is lowered.
(4) Since the air supply path is configured to reach the fuel cell (air electrode) via the reformer, the system configuration is complicated.

  Therefore, in view of the above circumstances, the present invention is easily and reliably included in the air without causing the generation of a new electrocatalyst poisoning substance, an increase in air temperature, a decrease in system efficiency, and a complicated system configuration. It is an object of the present invention to provide a fuel cell having a configuration capable of removing organic impurities.

A fuel cell according to a first aspect of the present invention for solving the above-described problems is a fuel cell having a configuration in which air around the fuel cell is sucked and supplied to the fuel cell main body by an intake means of an air supply line connected to the fuel cell main body.
Organic impurity removal that is disposed in the air supply line and in which the air around the fuel cell sucked by the intake means flows, and adsorbs and removes organic impurities contained in the air during the circulation It has the means.

Further, the fuel cell of the second invention is a fuel cell having a configuration in which air around the fuel cell is sucked and supplied to the fuel cell body by an intake means of an air supply line connected to the fuel cell body.
Organic impurity removal that is disposed in the air supply line and in which the air around the fuel cell sucked in by the intake means flows, and organic impurities contained in the air are absorbed and removed by the absorbing liquid during this flow It has the means.

The fuel cell of the third invention is the fuel cell of the second invention,
The organic impurity is disposed in the air supply line on the downstream side in the air flow direction of the organic impurity removal means, and the air after flowing through the organic impurity removal means flows, and the organic impurities contained in the air at the time of the flow It has the absorption liquid removal means which absorbs and removes this absorption liquid with water, It is characterized by the above-mentioned.

The fuel cell of a fourth invention is the fuel cell of any one of the first to third inventions,
Power generation voltage measuring means for measuring the power generation voltage of the fuel cell main body,
A time differential value of the generated voltage measured by the generated voltage measuring means is calculated, and the calculated time differential value is compared with a threshold value, and the generated voltage is abnormal when the time differential value exceeds the threshold value. Power generation voltage monitoring means for determining that there is,
It is characterized by having.

The fuel cell of the fifth invention is the fuel cell of any of the first to third inventions,
Power generation voltage measuring means for measuring the power generation voltage of the fuel cell main body,
By calculating the average value of the generated voltage measured by this generated voltage measuring means every fixed time, and calculating the time differential value of this average value, and comparing the calculated time differential value with a threshold value, Generated voltage monitoring means for determining that the generated voltage is abnormal when the time differential value exceeds the threshold;
It is characterized by having.

The fuel cell of the sixth invention is the fuel cell of any of the first to third inventions,
Power generation voltage measuring means for measuring the power generation voltage of the fuel cell main body,
An operating time measuring means for measuring the operating time of the fuel cell;
Based on the operation time of the fuel cell measured by the operation time measuring means and the power generation voltage drop curve of the fuel cell stored in advance, a threshold value of the generated voltage is calculated and measured by the threshold value and the generated voltage measuring means. A generated voltage monitoring means for comparing the generated voltage and determining that the generated voltage is abnormal when the generated voltage is lower than the threshold value;
It is characterized by having.

The fuel cell of the seventh invention is the fuel cell of the first invention,
The organic impurity removing means uses activated carbon as the adsorbent,
A pressure loss measuring means disposed in the air supply line for measuring the pressure loss of air in the organic impurity removing means;
A pressure loss monitoring means that compares the pressure loss measured by the pressure loss measuring means with a threshold value, and determines that the pressure loss is abnormal when the pressure loss is greater than the threshold value;
It is characterized by having.

The fuel cell of an eighth invention is the fuel cell of any one of the first to third inventions,
An organic impurity concentration measuring means disposed in the air supply line on the downstream side in the air flow direction of the organic impurity removing means and measuring the concentration of organic impurities in the air;
An organic impurity concentration monitor that compares the organic impurity concentration measured by the organic impurity concentration measuring means with a threshold value and determines that the organic impurity concentration is abnormal when the organic impurity concentration becomes higher than the threshold value. Means,
It is characterized by having.

  According to the fuel cell of the first invention, the air around the fuel cell, which is disposed in the air supply line and sucked by the intake means, flows, and the organic impurities contained in the air are adsorbed by the adsorbent during this flow. The organic impurity removing means for removing the organic catalyst can prevent the organic impurities from being supplied to the air electrode side of the fuel cell main body together with the air and poisoning the electrode catalyst on the air electrode side, and stable power generation voltage. Is obtained. Moreover, compared with the conventional case where organic impurities are combusted and decomposed by the heat of the reformer, generation of a new electrocatalyst poisoning substance such as CO, increase in air temperature, decrease in system efficiency, and system Organic impurities in the air can be easily and reliably removed without complicating the configuration.

  According to the fuel cell of the second invention, the air around the fuel cell, which is disposed in the air supply line and sucked by the intake means, flows, and the organic impurities contained in the air are absorbed by the absorbing liquid during this flow The organic impurity removing means for removing the organic catalyst can prevent the organic impurities from being supplied to the air electrode side of the fuel cell main body together with the air and poisoning the electrode catalyst on the air electrode side, and stable power generation voltage. Is obtained. Moreover, compared with the conventional case where organic impurities are combusted and decomposed by the heat of the reformer, generation of a new electrocatalyst poisoning substance such as CO, increase in air temperature, decrease in system efficiency, and system Organic impurities in the air can be easily and reliably removed without complicating the configuration.

  According to the fuel cell of the third aspect of the invention, the air after flowing through the organic impurity removing means is circulated in the air supply line on the downstream side in the air circulation direction of the organic impurity removing means. Therefore, there is no possibility that the absorbing liquid is supplied to the fuel cell body together with air to deteriorate the power generation performance of the fuel cell body. Furthermore, it is desirable that the air supplied to the fuel cell body contains a certain amount of moisture (water vapor), but the absorbing liquid removing means also functions as a humidifying means for that purpose.

  According to the fuel cell of the fourth aspect of the invention, in the generated voltage monitoring means, the time differential value of the generated voltage measured by the generated voltage measuring means is calculated, the calculated time differential value is compared with a threshold value, and the time differential value is calculated. Since it is determined that the generated voltage is abnormal when the value exceeds the threshold value, the organic impurity removing function is deteriorated due to the life or failure of the organic impurity removing means, and the abnormal fuel cell main body due to organic impurities Even if the generated voltage drops, the abnormal generated voltage drop can be detected by the generated voltage measuring means and the generated voltage monitoring means. That is, the soundness of the organic impurity removing means can be determined.

  According to the fuel cell of the fifth invention, in the generated voltage monitoring means, the average value of the generated voltage measured by the generated voltage measuring means is calculated every fixed time, and the time differential value of this average value is calculated, By comparing the calculated time differential value with a threshold value, it is determined that the generated voltage is abnormal when the time differential value exceeds the threshold value. Even if there is a small fluctuation in the power generation voltage of the battery body, this abnormal power generation occurs when the power generation voltage of the fuel cell body decreases abnormally due to organic impurities due to the deterioration of the organic impurity removal function of the organic impurity removal means. The voltage drop can be reliably detected without erroneous determination.

  According to the fuel cell of the sixth aspect of the invention, in the power generation voltage monitoring means, the power generation voltage is calculated based on the fuel cell operation time measured by the operation time measurement means and the fuel cell power generation voltage drop curve stored in advance. In order to calculate a threshold value, compare this threshold value with the generated voltage measured by the generated voltage measuring means, and determine that the generated voltage is abnormal when the generated voltage is lower than the threshold value. Even if the organic impurity removal function declines due to the life or failure of the means, and the abnormal generation voltage drop of the fuel cell due to organic impurities occurs, this abnormal decrease in the generated voltage is operated with the generation voltage measuring means. It can be detected by the time measuring means and the generated voltage monitoring means. That is, the soundness of the organic impurity removing means can be determined. Moreover, even if there is a small fluctuation in the generated voltage of the fuel cell main body due to some influence such as the fluctuation of the coolant temperature as described above, the threshold value considering this fluctuation can be used to detect abnormalities due to organic impurities. A decrease in the generated voltage of the fuel cell main body can be reliably detected without erroneous determination.

  According to the fuel cell of the seventh invention, in the pressure loss monitoring means, the pressure loss measured by the pressure loss measuring means is compared with a threshold value, and when the pressure loss becomes larger than the threshold value, the pressure loss is Even if the amount of adsorption of organic impurities or the like increases and the organic impurity removal function (organic impurity adsorption capacity) of the organic impurity remover 7 decreases, the decrease in the organic impurity removal capacity is pressured. It can be detected by the loss measuring means and the pressure loss monitoring means. That is, the soundness of the organic impurity removing means can be determined.

  According to the fuel cell of the eighth invention, when the organic impurity concentration monitoring means compares the organic impurity concentration measured by the organic impurity concentration measuring means with a threshold value, and the organic impurity concentration becomes higher than the threshold value. In order to determine that the concentration of organic impurities is abnormal, the organic impurity removal function (organic impurity adsorption capacity, organic impurity absorption capacity, etc.) ) Can be detected by the organic impurity concentration measuring means and the organic impurity concentration monitoring means. That is, the soundness of the organic impurity removing means can be determined.

  Embodiments of the present invention will be described below in detail with reference to the drawings.

<Embodiment 1>
FIG. 1 is a configuration diagram of a polymer electrolyte fuel cell (PEFC) according to Embodiment 1 of the present invention, FIG. 2 is a diagram illustrating a configuration example of an organic impurity remover provided in the fuel cell, and FIG. The figure which shows the measurement result of the fuel cell power generation voltage when not installing an organic impurity remover, FIG. 4 is the figure which shows the measurement result of the fuel cell power generation voltage when the said organic impurity remover is installed.

  As shown in FIG. 1, a polymer electrolyte fuel cell (PEFC) is provided with each cell of a PEFC stack 1 as a fuel cell main body via a fuel gas supply line (pipe) 2 and an air supply line (pipe) 3. By supplying fuel gas and air to the fuel electrode side and the air electrode side, respectively, these supply gases are reacted electrochemically in each cell of the PEFC stack 1 to generate electricity. The fuel gas and air remaining in the PEFC stack 1 without being consumed for power generation are discharged from the PEFC stack 1 through the fuel gas discharge line (pipe) 4 and the air discharge line (pipe) 5, respectively. Is done. The PEFC stack 1 has a configuration in which a plurality of cells each having a solid polymer electrolyte membrane sandwiched between a pair of electrode membranes are stacked.

  In some cases, pure hydrogen supplied from a cylinder or the like is used as the fuel gas. However, in a stationary fuel cell such as the illustrated example, gas fuel such as methane gas or liquid fuel such as kerosene is reformed by a reformer (not shown). In general, a reformed gas (hydrogen-containing gas) generated in this manner is used.

  On the other hand, air (atmosphere) around the fuel cell is used as the oxidant gas. More specifically, the air supply line 3 connected to the PEFC stack 1 is provided with a blower 6 as an intake means. The blower 6 sucks air around the fuel cell and supplies the air to the PEFC stack 1. It has become. Although not shown, a dust filter for removing dust contained in the air is provided at the inlet of the air supply line 3.

  In the first embodiment, an organic impurity remover 7 as an organic impurity removing unit is disposed in the air supply line 3. This organic impurity remover 7 uses activated carbon as an adsorbent for organic impurities. Therefore, in this case, the air around the fuel cell sucked by the blower 6 circulates through the activated carbon layer of the organic impurity remover 7, and organics such as xylene, toluene, gasoline, and light oil contained in the air at the time of distribution. Impurities are adsorbed and removed by activated carbon. As a configuration example of the organic impurity remover 7 using activated carbon, for example, as shown in FIG. 2, a porous plate 7b and a porous plate 7c are arranged inside a container 7a having air supply lines 3 connected to both sides. And the thing of the structure which accommodated the activated carbon layer 7d between these perforated plates 7b and 7c is employable. In this case, in particular, the porous plate 7b on the upstream side in the air flow direction functions as a dispersion plate for uniformly dispersing the air introduced into the container 7a into the activated carbon layer 7d.

  In the illustrated example, the organic impurity remover 7 is disposed on the upstream side in the air flow direction of the blower 6, but is not limited thereto, and may be disposed on the downstream side in the air flow direction of the blower 6. . Further, the organic impurity remover 7 provided in the air supply line 3 is not necessarily limited to the one using activated carbon, and may be one using other adsorbent. For example, the thing using the plaster application board which adsorb | sucks xylene, toluene, etc., the thing using the adsorption gel which adsorb | sucks xylene, toluene, etc. are also employable. Also in this case, when the air around the fuel cell sucked by the blower 6 flows through the organic impurity remover 7, the organic impurities contained in the air can be adsorbed and removed by the stucco coating plate or the adsorption gel. .

  As described above, according to the fuel cell of the first embodiment, the air around the fuel cell is sucked and supplied to the PEFC stack 1 by the blower 6 of the air supply line 3 connected to the PEFC stack 1. In the fuel cell, air around the fuel cell, which is disposed in the air supply line 3 and sucked by the blower 6 circulates, and organic impurities contained in the air are adsorbed (activated carbon, plaster coating plate) during this circulation. The organic impurity remover 7 that is adsorbed and removed by an adsorption gel or the like) prevents the organic impurities from being supplied to the air electrode side of the PEFC stack 1 together with air and poisoning the electrode catalyst on the air electrode side. And a stable generated voltage can be obtained. Moreover, compared with the conventional case where organic impurities are combusted and decomposed by the heat of the reformer, generation of a new electrocatalyst poisoning substance such as CO, increase in air temperature, decrease in system efficiency, and system Organic impurities in the air can be easily and reliably removed without complicating the configuration.

  In addition, based on FIG.3 and FIG.4 here, the test result when not installing the organic impurity removal device 7 using activated carbon in the air supply line 3 is demonstrated. 3 and 4, the horizontal axis represents the operating time of the fuel cell, and the vertical axis represents the power generation voltage of the fuel cell. When the organic impurity remover 7 was not installed in the air supply line 3, as shown in FIG. This large drop in power generation voltage is due to the volatilization of a part of the gasoline when the tank of a gas station near the test facility is replenished with gasoline from a tank truck, resulting in a high gasoline concentration in the air (atmosphere). This is because the electrode catalyst on the air electrode side is affected by gasoline vapor when the high gasoline concentration air is sucked by the blower 6. On the other hand, when the organic impurity remover 7 is installed in the air supply line 3, the activated carbon layer of the organic impurity remover 7 adsorbs and removes the gasoline vapor contained in the air, as shown in FIG. There was no significant drop in the generated voltage.

  Moreover, the overall generated voltage value was close to V1 in the case of FIG. 3, whereas it was close to V2 in the case of FIG. 4, and the latter was higher. In the case of FIG. 3, this is considered to be because the generated voltage decreases again due to the influence of the next gasoline vapor before the generated voltage recovers. In both cases of FIG. 3 and FIG. 4, the fluctuation of the generated voltage with a small amplitude is observed, which is considered to occur in conjunction with the fluctuation of the cooling water temperature. That is, although not shown, the PEFC stack 1 is configured to be cooled by the cooling water, and the temperature of the cooling water fluctuates due to a change in the outside air temperature. It is thought that the generated voltage also fluctuated somewhat.

<Embodiment 2>
FIG. 5 is a configuration diagram of a polymer electrolyte fuel cell (PEFC) according to Embodiment 2 of the present invention, and FIG. 6 is a diagram illustrating a configuration example of an organic impurity remover and an absorbent remover provided in the fuel cell. It is. In FIG. 5, the same parts as those in the first embodiment (FIG. 1) are denoted by the same reference numerals, and detailed description thereof is omitted.

  In the second embodiment, an organic impurity remover 11 as an organic impurity remover and an absorbent remover 12 as an absorbent remover are disposed on the air supply line 3. The absorbent remover 12 is disposed downstream of the organic impurity remover 11 in the air flow direction. In the illustrated example, the organic impurity remover 11 and the absorbing liquid remover 12 are disposed on the downstream side in the air flow direction of the blower 6. However, the present invention is not limited to this, and the upstream side of the blower 6 in the air flow direction. It may be arranged.

  The organic impurity remover 11 uses alcohol as an adsorbent for organic impurities. Therefore, in this case, the air around the fuel cell sucked by the blower 6 circulates in the alcohol of the organic impurity remover 11 and organics such as xylene, toluene, gasoline, light oil, etc. contained in the air during this circulation. Impurities are absorbed (dissolved) with alcohol and removed. Examples of the alcohol species used in the organic impurity remover 11 include ethanol.

  The absorbent remover 12 uses water as an alcohol absorbent. Therefore, in this case, the air after flowing through the organic impurity remover 11 circulates in the water, and the alcohol contained in the air during this flow (that is, when the air flows through the alcohol in the organic impurity remover 11) Alcohol vapor partially vaporized and mixed in the air) is absorbed and removed by water.

  As the organic impurity remover 11 and the absorption liquid remover 12, for example, those having a structure as shown in FIG. 6 can be used. The organic impurity remover 11 shown in FIG. 6 has a configuration in which an alcohol 11b such as ethanol is stored in a tank 11a, and the absorbent remover 12 shown in FIG. 6 has a configuration in which water 12b is stored in a tank 12a. It has become. The tip of the first air supply line 3 connected to the blower 6 is inserted into the alcohol 11b of the tank 11b. A second air supply line 3 is also interposed between the tanks 11a and 12a. The second air supply line 3 is connected at the base end to the upper portion of the tank 11b and communicates with the upper space 11c of the alcohol 11b in the tank 11a, and the distal end is inserted into the water 12b of the tank 12a. Has been. Further, the base end portion of the third air supply line 3 connected to the PEFC stack 1 is also connected to the upper portion of the tank 12a, and this third air supply line 3 is connected to the upper portion of the water 12b in the tank 12a. It leads to the space 12c.

  Therefore, in this case, the air sucked by the blower 6 is jetted into the alcohol 11b in the tank 11a of the organic impurity remover 11 through the first air supply line 3, and becomes air bubbles in the alcohol 11b. During the circulation, the organic impurities contained in the air are absorbed and removed by the alcohol 11b. Thereafter, the air is blown into the water 12b in the tank 12a of the absorbent remover 12 via the second air supply line 3 in a state containing some alcohol vapor, and circulates in the water 12b as bubbles. In the meantime, the alcohol contained in the air is absorbed and removed by the water 12b. Then, the air from which the organic impurities and alcohol are removed is supplied to the PEFC stack 1 through the third air supply line 3.

  As described above, according to the second embodiment, the air around the fuel cell is sucked and supplied to the PEFC stack 1 by the blower 6 of the air supply line 3 connected to the PEFC stack 1. In the air supply line 3, the air around the fuel cell sucked by the blower 6 circulates, and the organic impurities contained in the air are absorbed and removed by the alcohol during the circulation. Therefore, it is possible to prevent organic impurities from being supplied to the air electrode side of the PEFC stack 1 together with air and poisoning the electrode catalyst on the air electrode side, and a stable power generation voltage can be obtained. Moreover, compared with the conventional case where organic impurities are combusted and decomposed by the heat of the reformer, generation of a new electrocatalyst poisoning substance such as CO, increase in air temperature, decrease in system efficiency, and system Organic impurities in the air can be easily and reliably removed without complicating the configuration.

  Further, according to the second embodiment, the air is disposed in the air supply line 3 on the downstream side of the organic impurity remover 11 in the air flow direction, and the air after flowing through the organic impurity remover 11 flows. Since the absorbent remover 12 sometimes removes the alcohol contained in the air by absorbing it with water, there is no possibility that the alcohol is supplied to the PEFC stack 1 together with the air and the power generation performance of the PEFC stack 1 is deteriorated. Furthermore, it is desirable that the air supplied to the PEFC stack 1 contains a certain amount of moisture (water vapor), but the absorbent remover 12 also functions as a humidifier for that purpose. In this case, in order to increase the humidifying capacity of the absorbent remover 11, the water in the tank is heated to a certain temperature (for example, about 70 to 80 ° C.) by the heat of the reformer and other heat sources. It is preferable.

<Embodiment 3>
FIG. 7 is a configuration diagram of a polymer electrolyte fuel cell (PEFC) according to Embodiment 3 of the present invention, FIG. 8 is a diagram showing a power generation voltage characteristic of the fuel cell, and FIG. 9 is a power generation provided in the fuel cell. FIG. 10 is a flowchart showing other processing contents of the generated voltage monitoring apparatus, FIG. 11 is a flowchart showing further processing contents of the generated voltage monitoring apparatus, and FIG. 12 is the fuel. It is a figure which shows the electric power generation voltage characteristic and threshold value of a battery.

  In each of the fuel cells of Embodiment 3 shown in FIGS. 7 (a) and 7 (b), a voltmeter 21 as a generated voltage measuring means, a generated voltage monitoring device 22 as a generated voltage monitoring means, And a display device 23 as display means. Hereinafter, these configurations will be described in detail, and the other configurations are the same as those in the first and second embodiments (see FIGS. 1, 2, 5, and 6). The detailed description to be omitted is omitted.

  The voltmeter 21 measures the power generation voltage of the PEFC stack 1 and outputs a measurement signal of this power generation voltage to the power generation voltage monitoring device 22. The generated voltage monitoring device 22 is composed of a computer or the like. Based on the measured value of the generated voltage of the PEFC stack 1 inputted from the voltmeter 21, the generated voltage monitoring device 22 monitors an abnormal decrease in the generated voltage and sends the monitoring result to the display device 23. Output (details will be described later). The display device 23 is a display such as a CRT or LCD, and displays the monitoring result of the power generation voltage of the PEFC stack 1 input from the power generation voltage monitoring device 22 (details will be described later).

  In FIG. 8, the horizontal axis represents the operating time of the fuel cell, and the vertical axis represents the generated voltage of the fuel cell (PEFC stack). Normally, the power generation voltage of the PEFC stack 1 gradually decreases as the operation time elapses as shown in the assumed fuel cell deterioration (power generation voltage decrease) curve A as shown by the solid line in FIG. On the other hand, the power generation voltage of the PEFC stack 1 when the electrode catalyst on the air electrode side of the PEFC stack 1 is poisoned by organic impurities is a deterioration (power generation voltage drop) curve due to the organic impurities as shown by a one-dot chain line in FIG. As shown in B, the rate of decrease is larger than that of the curve A.

  In view of this, the generated voltage monitoring device 22 monitors the generated voltage abnormally by utilizing the difference in the decrease rate of the generated voltage between the normal time and the abnormal time. That is, the generated voltage monitoring device 22 performs processing as shown in the flowchart of FIG. As shown in FIG. 9, in the generated voltage monitoring device 22, when the power is turned on (when the operation of the fuel cell is started), measurement of the generated voltage V of the PEFC stack 1 is first started in step S1. . That is, input of the measurement signal of the generated voltage of the PEFC stack 1 output from the voltmeter 21 is started.

  Subsequently, in step S2, a time differential value (| dV / dt |) of the generated voltage measured by the voltmeter 21 is calculated. In step S3, the time differential value (| dV / dt |) of the generated voltage calculated in step S2 is compared with a preset threshold value a (a is a positive value) of the time differential value of the generated voltage. It is determined whether or not the time differential value (| dV / dt |) exceeds the threshold value a (whether or not | dV / dt |> a). In this case, it is not limited to the comparison between the absolute value of the time differential value (dV / dt) and the threshold value a, and the time differential value (dV / dt) may be directly compared with the threshold value -a. That is, it may be determined whether or not the time differential value (dV / dt) exceeds −a (whether or not dV / dt <−a). In addition, what is necessary is just to set the specific value of threshold value a (-a) to an appropriate value by a test etc.

  When it is determined in step S3 that the time differential value (| dV / dt |) does not exceed the threshold value a, or the time differential value (dV / dt) does not exceed -a, the process returns to step S2, and step S2 And the process of step S3 is repeated.

  On the other hand, when it is determined in step S3 that the time differential value (| dV / dt |) exceeds the threshold value a or the time differential value (dV / dt) exceeds −a, that is, the generated voltage of the PEFC stack 1 Is determined to be abnormal, in step S4, the determination result of the power generation voltage abnormality is output to the display device 23. As a result, the display device 23 performs display for warning that the generated voltage of the PEFC stack 1 is abnormal. In this case, an alarm may be issued by a buzzer or a lamp.

  By the way, the generated voltage of the PEFC stack 1 may have a small fluctuation due to some influence such as a fluctuation of the cooling water temperature, in addition to the case where it greatly decreases due to the influence of organic impurities as shown in FIG. In some cases, simply calculating the time differential value of the generated voltage and comparing it with a threshold value may result in an erroneous determination. Therefore, when a small fluctuation of the amplitude occurs in the generated voltage of the PEFC stack 1, a process as shown in the flowchart of FIG. 10 may be performed instead of the flowchart of FIG.

  That is, in this case, when the power generation voltage monitoring device 22 is turned on (when the operation of the fuel cell is started), first, in step S11, measurement of the power generation voltage V of the PEFC stack 1 is started. That is, input of the measurement signal of the generated voltage of the PEFC stack 1 output from the voltmeter 21 is started.

  Subsequently, in step S12, an averaging process is started. That is. The average value of the generated voltage of the PEFC stack 1 measured by the voltmeter 21 is calculated at regular intervals. It should be noted that the average value is calculated every time depending on the time differential value when a large power generation voltage drop is caused by organic impurities and the other fluctuations in the power generation voltage with a small amplitude. What is necessary is just to set suitably by performing a test etc. so that the difference with a time differential value at the time of being may become remarkable as much as possible.

  In step S13, a time differential value (| dV / dt |) of the average value of the generated voltage calculated in step S12 is calculated. In step S14, the time differential value (| dV / dt |) of the generated voltage average value calculated in step S13 is compared with a preset threshold value a (a is a positive value) of the time differential value of the generated voltage. Thus, it is determined whether or not the time differential value (| dV / dt |) exceeds the threshold value a (whether or not | dV / dt |> a). In this case, the comparison is not limited to the absolute value of the time differential value (dV / dt) and the threshold value a, but the time differential value (dV / dt) may be directly compared with the threshold value -a. That is, it may be determined whether or not the time differential value (dV / dt) exceeds −a (whether or not dV / dt <−a).

  If it is determined in step S14 that the time differential value (| dV / dt |) does not exceed the threshold value a, or the time differential value (dV / dt) does not exceed -a, the process returns to step S13, and step S13. And the process of step S14 is repeated.

  On the other hand, when it is determined in step S14 that the time differential value (| dV / dt |) exceeds the threshold value a or the time differential value (dV / dt) exceeds −a, that is, the generated voltage of the PEFC stack 1 Is determined to be abnormal, in step S15, the generated voltage abnormality determination result is output to the display device 23. As a result, the display device 23 performs display for warning that the generated voltage of the PEFC stack 1 is abnormal. In this case, an alarm may be issued by a buzzer or a lamp.

  Furthermore, instead of the flowcharts of FIGS. 9 and 10, processing as shown in the flowchart of FIG. 11 may be performed by the generated voltage monitoring device 22.

  That is, in this case, when the power generation voltage monitoring device 22 is turned on (when the operation of the fuel cell is started), first, in step S21, measurement of the power generation voltage V of the PEFC stack 1 is started. That is, input of the measurement signal of the generated voltage of the PEFC stack 1 output from the voltmeter 21 is started.

  Subsequently, in step S22, operation time measurement by the operation time measurement means is started. Any operation time measuring means may be used as long as it can measure the operation time of the PEFC stack 1, but for example, the time when the generated voltage of the PEFC stack 1 is measured by the voltmeter 21 (that is, the PEFC). The time when the stack 1 is generating power) is measured by the clock function of the power generation voltage monitoring device 22, and the time from when the start / stop switch of the fuel cell is turned on (started) to when it is turned off (stopped) It may be measured by the clock function of the generated voltage monitoring device 22.

  In step S23, a threshold value b for the generated voltage of the PEFC stack 1 is calculated. That is, an assumed fuel cell deterioration (power generation voltage drop) curve A as shown by a solid line in FIG. 12 is obtained in advance by a test or the like, stored in the power generation voltage monitoring device 22, and stored in advance. Based on the generated voltage drop curve A of the fuel cell and the operating time of the fuel cell measured by the operating time measuring means, the value is lower than the value of the generated voltage drop curve A as shown by a two-dot chain line in FIG. The threshold value b is calculated. As a method for calculating the threshold value b, for example, a value obtained by subtracting a constant value from the value of the power generation voltage decrease curve A at each operation time may be calculated, or the value of the power generation voltage decrease curve A at each operation time may be constant. A value obtained by multiplying the ratio may be calculated. In addition, when the fluctuation | variation with a small amplitude arises in the power generation voltage of PEFC stack 1 by some influences, such as the fluctuation | variation of a cooling water temperature as mentioned above, the amplitude of this fluctuation | variation is also considered and it determines erroneously by step S24 mentioned later. A value without fear may be set as the threshold value b.

  In step S24, the generated voltage V of the PEFC stack 1 measured by the voltmeter 21 is compared with the threshold value b calculated in step S23, and whether or not the generated voltage V is lower than the threshold value b (V <b). Whether or not).

  As a result, when it is determined in step S24 that the generated voltage V is not lower than the threshold value b, the process returns to step S23, and the processes in steps S23 and S24 are repeated.

  On the other hand, for example, in the operation time t1 or t2 of FIG. 12, when it is determined in step S24 that the generated voltage V has decreased below the threshold value b, that is, when it is determined that the generated voltage of the PEFC stack 1 is abnormal, step S25 is performed. Then, the determination result of the generated voltage abnormality is output to the display device 23. As a result, the display device 23 performs display for warning that the generated voltage of the PEFC stack 1 is abnormal. In this case, an alarm may be issued by a buzzer or a lamp.

  As described above, according to the third embodiment, in the generated voltage monitoring device 22, the time differential value | dV / dt | of the generated voltage V of the PEFC stack 1 measured by the voltmeter 21 as shown in FIG. (Or dV / dt) is calculated, the calculated time differential value is compared with the threshold value a (or -a), and the generated voltage is abnormal when the time differential value exceeds the threshold value. In order to determine, the organic impurity removing device 7 in FIG. 7A or the organic impurity removing device 11 in FIG. Even if the power generation voltage of the stack 1 decreases, this abnormal power generation voltage decrease can be detected by the voltmeter 21 and the power generation voltage monitoring device 22. That is, the soundness of the organic impurity removers 7 and 11 can be determined.

  Furthermore, according to the third embodiment, the generated voltage monitoring device 22 calculates the average value of the generated voltage V measured by the voltmeter 21 at regular intervals as shown in FIG. When the time differential value | dV / dt | (or dV / dt) is calculated, the calculated time differential value is compared with the threshold value a (or -a), and the time differential value exceeds the threshold value In the case where it is determined that the generated voltage is abnormal, the organic impurity remover is used even when a small fluctuation in the generated voltage of the PEFC stack 1 occurs due to some influence such as the fluctuation of the cooling water temperature as described above. When the abnormal power generation voltage drop of the PEFC stack 1 due to the organic impurities is reduced due to the organic impurity removal function 7 or 11, the abnormal power generation voltage drop can be reliably detected without erroneous determination. .

  Furthermore, according to the third embodiment, in the generated voltage monitoring device 22, as shown in FIG. 11, the operating time of the fuel cell measured by the operating time measuring means and the generated voltage of the fuel cell stored in advance are stored. When the threshold value b of the generated voltage is calculated based on the data of the decrease curve A, the threshold value b is compared with the generated voltage V measured by the voltmeter 21, and the generated voltage V falls below the threshold value b. When it is determined that the generated voltage V is abnormal, these organic impurity removal functions are caused by the life or failure of the organic impurity remover 7 in FIG. 7A or the organic impurity remover 11 in FIG. Even if an abnormal decrease in the generated voltage of the PEFC stack 1 due to organic impurities occurs, this abnormal decrease in the generated voltage can be detected by the voltmeter 21 and the generated voltage monitoring device 22. That is, the soundness of the organic impurity removers 7 and 11 can be determined. Moreover, even if a small fluctuation in the generated voltage of the PEFC stack 1 occurs due to some influence such as the fluctuation of the cooling water temperature as described above, the threshold value b in consideration of this fluctuation can be changed by the organic impurities. An abnormal decrease in the generated voltage of the PEFC stack 1 can be reliably detected without erroneous determination.

<Embodiment 4>
FIG. 13 is a configuration diagram of a polymer electrolyte fuel cell (PEFC) according to Embodiment 4 of the present invention. FIG. 14 is a diagram showing a pressure loss curve and a threshold value of an organic impurity remover provided in the fuel cell. 15 is a flowchart showing the processing contents of the pressure loss monitoring device provided in the fuel cell. In FIG. 13, the same parts as those in the first embodiment (see FIGS. 1 and 2) are denoted by the same reference numerals, and detailed description thereof is omitted.

  In the fuel cell of the fourth embodiment shown in FIG. 13, a differential pressure gauge 31 as pressure loss monitoring means provided in the air supply line 3, a pressure loss monitoring device 32 as pressure loss monitoring means, and display means Display device 33.

  The differential pressure gauge 31 measures the differential pressure of air between the upstream and downstream sides in the air flow direction in the organic impurity remover 7 (see FIG. 2) using activated carbon, that is, the pressure loss of air in the organic impurity remover 7. The pressure loss measurement signal is output to the pressure loss monitoring device 32. The pressure loss monitoring device 32 is composed of a computer or the like. The pressure loss monitoring device 32 monitors the rise of the pressure loss based on the measured value of the pressure loss of the organic impurity remover 7 input from the differential pressure gauge 31 and displays the monitoring result on the display device 33. (Details will be described later). The display device 33 is a display such as a CRT or LCD, and displays the pressure loss monitoring result of the organic impurity remover 7 input from the pressure loss monitoring device 32 (details will be described later).

  The pressure loss monitoring device 32 performs processing as shown in the flowchart of FIG. That is, when the pressure loss monitoring device 32 is turned on (when the operation of the fuel cell is started), first, in step S31, measurement of the pressure loss ΔP of the organic impurity remover 7 is started. That is, the input of the measurement signal of the pressure loss of the organic impurity remover 7 output from the differential pressure gauge 31 is started.

  In step S32, the pressure loss ΔP of the organic impurity remover 7 measured by the differential pressure gauge 31 and the pressure loss threshold c are compared, and whether or not the pressure loss ΔP is larger than the threshold c (ΔP> c). As a result, when it is determined in step S32 that the pressure loss ΔP is not greater than the threshold value c, the process of step S32 is repeated.

  On the other hand, when it is determined in step S32 that the pressure loss ΔP has become larger than the threshold value c, that is, when it is determined that the pressure loss of the organic impurity remover 7 is abnormal, in step S33, the determination result of this pressure loss abnormality Is output to the display device 33. As a result, the display device 33 performs a display for warning that the generated voltage of the organic impurity remover 7 is abnormal. In this case, an alarm may be issued by a buzzer or a lamp.

  In FIG. 15, the horizontal axis represents the operating time of the fuel cell, and the vertical axis represents the pressure loss of the organic impurity remover. In the organic impurity remover 7 using activated carbon, the amount of organic impurities adsorbed on the activated carbon layer increases with the passage of operating time, and the organic impurities are not only on the pores of the activated carbon layer but also on the surface of the air flow path in the activated carbon layer. Since impurities become attached, for example, the pressure loss ΔP of the organic impurity remover 7 gradually increases as shown in the pressure loss curve C illustrated by the solid line in FIG. In addition, the pressure loss ΔP of the organic impurity remover 7 is not only organic impurities but also impurities other than organic impurities such as fine dust that cannot be removed by the dust filter are adsorbed and deposited on the activated carbon layer, It may also increase due to clogging of a part of the activated carbon layer pulverized by vibration or the like. For example, when the pressure loss ΔP becomes larger than the threshold value c illustrated by the one-dot chain line in FIG. 15 at the operation time t3 in FIG. 15, the pressure loss monitoring device 32 determines that the pressure loss ΔP is abnormal. In addition, what is necessary is just to set the specific value of the threshold value c to an appropriate value by a test.

  As described above, according to the fourth embodiment, in the pressure loss monitoring device 32, the pressure loss ΔP measured by the differential pressure gauge 31 is compared with the threshold c as shown in FIG. Since it is determined that the pressure loss ΔP is abnormal when it exceeds c, the amount of adsorption of organic impurities and the like increases, and the organic impurity removal function (organic impurity adsorption capability) of the organic impurity remover 7 decreases. Even so, the decrease in the organic impurity removal capability can be detected by the differential pressure gauge 31 and the pressure loss monitoring device 32. That is, the soundness of the organic impurity remover 7 can be determined.

<Embodiment 5>
FIG. 16 is a block diagram of a polymer electrolyte fuel cell (PEFC) according to Embodiment 5 of the present invention, and FIG. 17 is a flowchart showing processing contents of an organic impurity concentration monitoring device provided in the fuel cell.

  In each of the fuel cells of the fifth embodiment shown in FIGS. 16A and 16B, the organic impurity concentration meter 41 as the organic impurity concentration measuring means and the organic impurity concentration concentration as the organic impurity concentration monitoring means. It has a monitoring device 42 and a display device 43 as a display means. Hereinafter, these configurations will be described in detail, and the other configurations are the same as those in the first and second embodiments (see FIGS. 1, 2, 5, and 6). The detailed description to be omitted is omitted.

  In FIG. 16 (a), the organic impurity concentration meter 41 is disposed downstream of the organic impurity remover 7 in the air supply direction in the air supply line 3, and in FIG. 16 (b), the organic impurity concentration meter 41 is connected to the air supply line. 3 is disposed downstream of the organic impurity remover 11 in the air flow direction. Therefore, in the organic impurity concentration meter 41 of FIG. 16A, the concentration of organic impurities contained in the air after passing through the organic impurity remover 7 is measured, and the measurement signal of the organic impurity concentration is monitored as the organic impurity concentration monitor. Output to the device 42. In the organic impurity concentration meter 41 of FIG. 16B, the concentration of organic impurities contained in the air after passing through the organic impurity remover 11 is measured, and the measurement signal of the organic impurity concentration is used as the organic impurity concentration monitoring device 42. Output to.

  The organic impurity concentration monitoring device 42 is composed of a computer or the like. The organic impurity concentration monitoring device 42 monitors the increase of the organic impurity concentration based on the measured value of the organic impurity concentration input from the organic impurity concentration meter 41 and sends the monitoring result to the display device 43. Output (details will be described later). The display device 43 is a display such as a CRT or LCD and displays the monitoring result of the organic impurity concentration input from the pressure loss monitoring device 42 (details will be described later).

The organic impurity concentration monitoring device 42 performs processing as shown in the flowchart of FIG. That is, in the organic impurity concentration monitoring device 42, when the power is turned on (when the operation of the fuel cell is started), first, measurement of the organic impurity concentration ρ _HC is started in step S41. That is, the input of the measurement signal of the organic impurity concentration output from the organic impurity concentration 41 is started.

In step S42, the organic impurity concentration ρ _HC measured at the organic impurity concentration 41 is compared with the threshold value d of the organic impurity concentration to determine whether the organic impurity concentration ρ _HC is higher than the threshold value d (Δρ _HC It is determined whether or not> d. In addition, what is necessary is just to set the specific value of the threshold value c to an appropriate value by a test. If it is determined in step S42 that the organic impurity concentration ρ _HC is not higher than the threshold value d, the process of step S42 is repeated.

On the other hand, when it is determined in step S42 that the organic impurity concentration ρ _HC has become higher than the threshold value d due to the increase in the concentration of organic impurities contained in the air due to the lifetime or failure of the organic impurity removers 7 and 11, That is, when it is determined that the organic impurity concentration ρ _HC is abnormal, the determination result of the abnormal organic impurity concentration is output to the display device 43 in step S43. As a result, the display device 43 performs a display for warning that the organic impurity concentration ρ _HC is abnormal. In this case, an alarm may be issued by a buzzer or a lamp.

As described above, according to the fifth embodiment, the organic impurity concentration monitoring device 42 compares the organic impurity concentration ρ _HC measured by the organic impurity concentration meter 41 with the threshold value d as shown in FIG. Since the organic impurity concentration ρ _HC is determined to be abnormal when the organic impurity concentration ρ _HC is higher than the threshold value d, the organic impurity removal is caused by an increase in the amount of organic impurities adsorbed or absorbed or a failure. Even if the organic impurity removal function (organic impurity adsorption capacity, organic impurity absorption capacity) of the vessels 7 and 11 is reduced, the decrease in the organic impurity removal capacity is detected by the organic impurity concentration 41 and the organic impurity concentration monitoring device 42. Can do. That is, the soundness of the organic impurity removers 7 and 11 can be determined.

  The present invention relates to a fuel cell, and is useful when applied to air around the fuel cell as an oxidant gas supplied to the fuel cell body.

1 is a configuration diagram of a polymer electrolyte fuel cell (PEFC) according to Embodiment 1 of the present invention. FIG. It is a figure which shows the structural example of the organic impurity removal device with which the said fuel cell was equipped. It is a figure which shows the measurement result of the fuel cell power generation voltage in case the said organic impurity remover is not installed. It is a figure which shows the measurement result of the fuel cell power generation voltage at the time of installing the said organic impurity remover. It is a block diagram of the polymer electrolyte fuel cell (PEFC) based on Embodiment 2 of this invention. It is a figure which shows the structural example of the organic impurity removal device and absorption liquid removal device with which the said fuel cell was equipped. It is a block diagram of the polymer electrolyte fuel cell (PEFC) based on Embodiment 3 of this invention. It is a figure which shows the power generation voltage characteristic of the said fuel cell. It is a flowchart which shows the processing content of the generated voltage monitoring apparatus with which the said fuel cell was equipped. It is a flowchart which shows the other processing content of the said generated voltage monitoring apparatus. It is a flowchart which shows the other processing content of the said power generation voltage monitoring apparatus. It is a figure which shows the electric power generation voltage characteristic and threshold value of the said fuel cell. It is a block diagram of the polymer electrolyte fuel cell (PEFC) based on Embodiment 4 of this invention. It is a figure which shows the pressure loss curve and threshold value of the organic impurity removal device with which the said fuel cell was equipped. It is a flowchart which shows the processing content of the pressure loss monitoring apparatus with which the said fuel cell was equipped. It is a block diagram of the polymer electrolyte fuel cell (PEFC) based on Embodiment 5 of this invention. It is a flowchart which shows the processing content of the organic impurity concentration monitoring apparatus with which the said fuel cell was equipped.

Explanation of symbols

1 PEFC stack (fuel cell body)
2 Fuel gas supply line 3 Air supply line 4 Fuel gas discharge line 5 Air discharge line 6 Blower 7 Organic impurity remover 7a Container 7b, 7c Perforated plate 7d Activated carbon layer 11 Organic impurity remover 11a Tank 11b Alcohol 11c Space 12 Absorbed liquid removal Vessel 12a tank 12b water 12c space 21 voltmeter 22 generated voltage monitoring device 23 display device 31 differential pressure gauge 32 pressure loss monitoring device 33 display device 41 organic impurity concentration meter 42 organic impurity concentration monitoring device 43 display device

Claims (8)

In a fuel cell having a configuration in which air around the fuel cell is sucked and supplied to the fuel cell main body by an intake means of an air supply line connected to the fuel cell main body.
Organic impurity removal that is disposed in the air supply line and in which the air around the fuel cell sucked by the intake means flows, and adsorbs and removes organic impurities contained in the air during the circulation A fuel cell comprising means. In a fuel cell having a configuration in which air around the fuel cell is sucked and supplied to the fuel cell main body by an intake means of an air supply line connected to the fuel cell main body.
Organic impurity removal that is disposed in the air supply line and in which the air around the fuel cell sucked in by the intake means flows, and organic impurities contained in the air are absorbed and removed by the absorbing liquid during this flow A fuel cell comprising means. The fuel cell according to claim 2, wherein
The organic impurity is disposed in the air supply line on the downstream side in the air flow direction of the organic impurity removal means, and the air after flowing through the organic impurity removal means flows, and the organic impurities contained in the air at the time of the flow A fuel cell comprising an absorbing liquid removing means for absorbing and removing the absorbing liquid with water. The fuel cell according to any one of claims 1 to 3,
Power generation voltage measuring means for measuring the power generation voltage of the fuel cell main body,
A time differential value of the generated voltage measured by the generated voltage measuring means is calculated, and the calculated time differential value is compared with a threshold value, and the generated voltage is abnormal when the time differential value exceeds the threshold value. Power generation voltage monitoring means for determining that there is,
A fuel cell comprising: The fuel cell according to any one of claims 1 to 3,
Power generation voltage measuring means for measuring the power generation voltage of the fuel cell main body,
By calculating the average value of the generated voltage measured by this generated voltage measuring means every fixed time, and calculating the time differential value of this average value, and comparing the calculated time differential value with a threshold value, Generated voltage monitoring means for determining that the generated voltage is abnormal when the time differential value exceeds the threshold;
A fuel cell comprising: The fuel cell according to any one of claims 1 to 3,
Power generation voltage measuring means for measuring the power generation voltage of the fuel cell main body,
An operating time measuring means for measuring the operating time of the fuel cell;
Based on the operation time of the fuel cell measured by the operation time measuring means and the power generation voltage drop curve of the fuel cell stored in advance, a threshold value of the generated voltage is calculated and measured by the threshold value and the generated voltage measuring means. A generated voltage monitoring means for comparing the generated voltage and determining that the generated voltage is abnormal when the generated voltage is lower than the threshold value;
A fuel cell comprising: The fuel cell according to claim 1, wherein
The organic impurity removing means uses activated carbon as the adsorbent,
A pressure loss measuring means disposed in the air supply line for measuring the pressure loss of air in the organic impurity removing means;
A pressure loss monitoring means that compares the pressure loss measured by the pressure loss measuring means with a threshold value, and determines that the pressure loss is abnormal when the pressure loss is greater than the threshold value;
A fuel cell comprising: The fuel cell according to any one of claims 1 to 3,
An organic impurity concentration measuring means disposed in the air supply line on the downstream side in the air flow direction of the organic impurity removing means and measuring the concentration of organic impurities in the air;
An organic impurity concentration monitor that compares the organic impurity concentration measured by the organic impurity concentration measuring means with a threshold value and determines that the organic impurity concentration is abnormal when the organic impurity concentration becomes higher than the threshold value. Means,
A fuel cell comprising:

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