JP2011181424A - Fuel cell power generation system - Google Patents

Abstract

An object of the present invention is to efficiently discharge impurities deposited in a hot water tank when the temperature of the water in the hot water tank is high.
A fuel cell, a hot water tank for collecting and storing heat generated from the fuel cell with water, and a control unit are provided. The hot water storage tank has a water outlet near the bottom and a temperature detection unit that detects the temperature of the water in the hot water storage tank. A first upper limit temperature in the temperature of the water in the hot water tank is provided in advance in the control unit. When the temperature detected by the temperature detection unit exceeds the first upper limit temperature and the operation of the fuel cell is continued, the control unit discharges water in the hot water storage tank from the discharge port.
[Selection] Figure 1

Description

  The present invention relates to a fuel cell power generation system, and more particularly, to control for improving its convenience.

  A polymer electrolyte fuel cell uses a hydrogen-containing gas as a fuel gas and air containing oxygen as an oxidant. Electric power is generated by reacting these fuel gas and oxidant. On the other hand, heat is also generated with this power generation. In a fuel cell, electric power and heat generated by power generation can be supplied to the outside, and high energy efficiency can be obtained.

  In such a fuel cell system, a method of heating water with generated heat (exhaust heat) and storing it in a hot water storage tank is well known as the heat recovery method (for example, Patent Document 1). And exhaust heat is utilized efficiently by utilizing this heated hot water for hot water supply etc. A conventional fuel cell system is shown in FIG. The fuel cell system is generated from the fuel cell 103 that generates electric power and heat from the oxidant and the fuel gas, the inverter 110 that AC / DC converts the output from the fuel cell 103 and supplies it to an external power load, and the fuel cell 103 A hot water storage tank 109 for storing heat. Also, a fuel cell cooling water circulation path 112 that circulates cooling water that recovers heat generated in the fuel cell 103, a hot water tank water circulation path 113 that circulates water in the hot water tank 109, and water that flows through the fuel cell cooling water circulation path 112; A heat exchanger 107 that performs heat exchange with water flowing through the hot water tank water circulation path 113 is further provided. Thereby, the heat generated from the fuel cell 103 can be stored in the hot water tank 109.

  In the fuel cell system described above, exhaust heat associated with power generation is recovered to heat the water in the hot water storage tank 109. If the hot water storage tank 109 is already full of hot water, Cooling becomes insufficient, and power generation efficiency decreases or power generation becomes impossible. In such a case, the power generation must be stopped or the exhaust heat must be discarded as it is. However, it is not desirable to stop power generation or discard waste heat from the viewpoint of flexible response to power demand and energy efficiency.

  Therefore, a fuel cell power generation system that changes the temperature of water (hot water) in the hot water tank 109 in accordance with electric power demand has been proposed (for example, Patent Document 2). In this system, the temperature of the water (hot water) in the hot water storage tank 109 is controlled to change at a temperature between a certain upper limit temperature and a lower limit temperature. For example, when the demand for hot water supply is low and the demand for electric power is high, the temperature of water (hot water) in the hot water storage tank 109 is controlled to be close to the upper limit temperature (for example, 80 ° C.). As a result, an efficient fuel cell power generation system is realized in accordance with electric power demand and hot water supply demand.

JP 2000-340244 A JP 2006-294535 A

  However, when the temperature of the hot water in the hot water tank 109 exceeds 60 ° C., metal ions contained in the water are insolubilized (for example, calcium carbonate from the Ca component) and precipitated as precipitates in the hot water tank 109. This may cause problems in the operation of the accumulated fuel cell 103.

  The present invention solves the above-described conventional problems, and even when the upper limit temperature of hot water in the hot water storage tank 109 is changed to a high temperature in accordance with the power demand, the problem of operation of the fuel cell 103 due to the precipitate is reduced. An object of the present invention is to provide a fuel cell power generation system that can be prevented.

  In order to solve the above-described problems, a fuel cell power generation system of the present invention includes a fuel cell, a hot water tank that collects and stores heat generated from the fuel cell with water, and a control unit. The hot water storage tank has a water outlet near the bottom and a temperature detection unit that detects the temperature of the water in the hot water storage tank. A first upper limit temperature in the temperature of the water in the hot water tank is provided in advance in the control unit. When the temperature detected by the temperature detection unit exceeds the first upper limit temperature and the operation of the fuel cell is continued, the control unit causes the water in the hot water tank to be discharged from the discharge port.

  According to the fuel cell power generation system of the present invention, it is possible to minimize the influence of precipitates caused by impurities precipitated from the water in the hot water storage tank due to the increase in the temperature of the water in the hot water storage tank. Therefore, the convenience of the fuel cell power generation system can be improved.

1 is a block diagram of a fuel cell power generation system according to Embodiment 1 of the present invention. Schematic diagram of a hot water tank in the fuel cell power generation system according to Embodiment 1 of the present invention. The schematic diagram of the other hot water storage tank in the fuel cell power generation system by Embodiment 1 of this invention Block diagram of a fuel cell power generation system according to Embodiment 2 of the present invention Block diagram of a conventional fuel cell power generation system

(Embodiment 1)
FIG. 1 is a block diagram of a fuel cell power generation system according to Embodiment 1 of the present invention. This fuel cell power generation system includes a fuel processor 1, a fuel cell 3, a control unit 5, a heat exchanger 7, and a hot water tank 9. The fuel processor 1 causes a reforming reaction between water vapor and a raw material gas such as city gas to generate a hydrogen-containing gas. The fuel cell 3 uses the hydrogen-containing gas as fuel and generates power using air. In the present embodiment, the fuel cell 3 is a solid polymer fuel cell using a solid polymer thin film as an electrolyte.

  The hydrogen-containing gas is supplied to a fuel electrode (not shown) of the fuel cell 3 and consumed by a reaction relating to power generation in the fuel cell 3. However, since the fuel cell 3 cannot consume all the hydrogen-containing gas in the fuel gas and can be used for power generation, about 20% of the supplied hydrogen-containing gas is discharged together with carbon dioxide as an exhaust gas. This exhaust gas is burned by the fuel processor 1 and used for heating a reforming section (not shown).

  On the other hand, air containing oxygen as an oxidant is supplied to an air electrode (not shown) of the fuel cell 3. Oxygen reacts with the hydrogen-containing gas supplied to the fuel electrode by a reaction related to power generation in the fuel cell 3 to become water. This water-derived water vapor, unreacted oxygen, unreacted nitrogen and the like are discharged as exhaust gas.

  The electric power generated by the fuel cell 3 is supplied to the load 11 via the inverter 10. The inverter 10 converts the electric power generated by the fuel cell 3 into a current state and voltage required for the load 11, detects the electric power required from the load 11, and feeds it back to the control unit 5. This is used for controlling the power generated by the fuel cell in the unit 5. The heat generated in the fuel cell 3 is stored in the hot water tank 9. Specifically, the heat generated in the fuel cell 3 is stored in the hot water tank 9 as described below. The fuel cell 3 includes a fuel cell cooling water circulation path 12 that circulates cooling water that recovers heat generated in the fuel cell 3. The fuel cell 3 is cooled by recovering the heat generated in the fuel cell 3 by the cooling water. On the other hand, the hot water tank 9 includes a hot water tank water circulation path 13 for circulating water (hot water) in the hot water tank 9. A heat exchanger 7 is provided between the fuel cell cooling water circulation path 12 and the hot water tank water circulation path 13 for exchanging heat of water flowing through both circulation paths. In the heat exchanger 7, the heat of the cooling water flowing through the fuel cell cooling water circulation path 12 is transferred to the water flowing through the hot water tank water circulation path 13. As described above, the heat generated in the fuel cell 3 can be recovered and stored in the hot water tank 9. Although not shown, pumps and flow valves for circulating the cooling water and the water in the hot water tank 9 are provided. The controller 5 also controls the operation of this pump and flow valve. Moreover, the water (hot water) stored in the hot water tank 9 is used for heating and hot water supply.

  Next, a more specific configuration of the hot water tank will be described with reference to FIG. FIG. 2 is a schematic diagram of a hot water tank in the fuel cell power generation system according to the first embodiment. The hot water storage tank 9 includes a city water inlet 21, a hot water supply port 22, a hot water tank water circulation path inlet 13 a, a hot water tank water circulation path outlet 13 b, a discharge port 23, and a temperature detection unit 24.

  A city water inlet 21, which is an inlet of water into the hot water tank 9, is connected to a water supply or the like, and supplies water into the hot water tank 9. At this time, the amount and timing of water supply are controlled by the control unit 5 based on the amount of hot water used, the temperature of the water (hot water) in the hot water storage tank 9, and the like. The temperature of the water in the hot water tank 9 is measured by a temperature detection unit 24 provided in the hot water tank 9 and sent to the control unit 5.

  Water (hot water) in the hot water tank 9 is supplied to a hot water supply facility or the like from a hot water supply port 22 that is a water outlet to the outside of the hot water tank 9.

  Water (hot water) in the hot water tank 9 circulates through the hot water tank water circulation path 13 (always). Specifically, the water (hot water) in the hot water tank 9 flows into the hot water tank water circulation path 13 from the hot water tank water circulation path inlet 13a, and flows into the hot water tank 9 again from the hot water tank water circulation path outlet 13b. The hot water tank water circulation path 13 is provided with a heat exchanger 7 that performs heat exchange with the fuel cell cooling water circulation path 12. That is, the water in the hot water tank 9 flows through the hot water tank water circulation path 13 and is heated by the heat of the cooling water recovered from the fuel cell 3. Thereby, the heat generated in the fuel cell 3 is stored in the water (hot water) in the hot water tank 9. The flow rate of the water (hot water) circulating through the hot water tank 9 and the hot water tank water circulation path 13 is controlled by the control unit 5 based on the temperature of the water (hot water) in the hot water tank 9 and the amount of hot water used. .

  As shown in FIG. 2, the city water inlet 21, the hot water tank water circulation path inlet 13 a, and the temperature detector 24 are preferably provided near the bottom of the hot water tank 9. The hot water tank water circulation path outlet 13b and the hot water supply port 22 are preferably provided above the hot water tank 9. This is because, in the hot water tank 9, a region where the temperature of water is relatively low is formed in the lower portion and a region where the temperature of water is relatively high is formed in the upper portion. That is, since the water supplied from the city water inlet 21 is a normal tap water temperature (about 10 to 20 ° C.), it is more efficient to flow in the vicinity of the region where the temperature of the water is relatively low. . On the contrary, since it is necessary to supply high temperature water (hot water) from the hot water supply port 22, it is possible to supply hot water more efficiently if it is provided in a high temperature region (above).

  Next, control by the control unit 5 will be described. As described above, the heat generated in the fuel cell 3 along with the power generation is constantly stored in the hot water tank 9 through the heat exchanger 7. That is, the fuel cell 3 is constantly cooled by the cooling water. This is because if the fuel cell 3 is too hot, there is a risk that the operating efficiency may decrease or the operating life may decrease. Therefore, a predetermined first upper limit temperature (for example, 60 ° C.) is set in the control unit 5 as the temperature of water (hot water) in the hot water tank 9. This is because the temperature of the water in the hot water tank 9 and the operating temperature of the fuel cell 3 are linked to each other, and the operating temperature of the fuel cell 3 increases as the temperature of the water in the hot water tank 9 increases. The first upper limit temperature is a temperature at which the operation of the fuel cell 3 can be performed without any problem, and is determined in consideration of a temperature that prevents the precipitation of calcium carbonate and the generation of bacteria such as Legionella. do it. During normal operation, the operation is controlled so that the temperature of the water (hot water) in the hot water storage tank is equal to or lower than the first upper limit temperature. Here, for example, when the demand for electric power is high but the demand for heat such as hot water supply is low, the amount of heat used from the hot water tank is smaller than the amount of heat generated by power generation, and as a result, the amount of heat stored in the hot water tank is reduced. It will increase. As a result, the temperature of the water (hot water) in the hot water tank rises steadily.

  Finally, even when the temperature of the water in the hot water tank reaches the first upper limit temperature, if there is a power generation request for the fuel cell 3, the controller 5 determines whether or not to continue the operation. For example, if the load 11 consumes a large amount of power and the operation of the fuel cell 3 is stopped, the breaker of the home and the power system will drop, but if the power generation in the fuel cell is continued, the risk of the breaker falling can be avoided. The control unit 5 continues the operation of the fuel cell 3. As a result, the control unit 5 continues the operation at a temperature exceeding the first upper limit temperature.

  The control unit 5 detects that there is a power generation request to the fuel cell 3, for example, as follows. When the inverter 10 detects that there is a power generation request from the load 11, the inverter 10 notifies the control unit 5 that there is a power generation request from the load 11, and the fuel cell 3 has a power generation request from the load 11. Is detected.

  In such a case, it is desirable to set the second upper limit temperature as the upper limit temperature. The second upper limit temperature is preferably set to, for example, 80 to 90 ° C. in consideration of the limit temperature of the solid electrolyte of the fuel cell, the boiling point of water, and the like. However, the second upper limit temperature is appropriately set according to the type of electrolyte used, the structure of the fuel cell, and the like, and is not limited to the above range.

  As described above, the temperature of the water (hot water) in the hot water tank 9 exceeds the first upper limit temperature and the operation is continued. As a result, the temperature of the water (hot water) in the hot water tank 9 reaches the second upper limit temperature. In this case, it is preferable that the control unit 5 stops the operation of the fuel cell 3. Thereby, deterioration of the solid electrolyte of the fuel cell 3 and deterioration and damage of piping due to boiling of water can be prevented.

  As described above, when the control unit 5 operates the fuel cell with the second upper limit temperature as the upper limit and the temperature of the water (hot water) in the hot water tank 9 exceeds the first upper limit temperature, the water (hot water) in the hot water tank 9 is reached. ) From which impurities such as calcium carbonate are deposited and a precipitate is formed. This impurity is not so preferable because it precipitates and accumulates in a large amount and may hinder the circulation of water in the hot water tank 9.

  Therefore, the controller 5 discharges water in the hot water tank 9 from the discharge port 23 when the temperature exceeds the first upper limit temperature and the operation of the fuel cell 3 is continued. Thereby, the deposit is discharged from the hot water tank 9. Thereby, the deposit accumulated in the hot water tank 9 can be effectively discharged to the outside of the hot water tank 9, and malfunction of the fuel cell 3 can be prevented.

  In addition, a precipitate can be discharged | emitted more effectively by setting it as the following structures. The control part 5 is provided with the memory | storage part 40 which measures the period which is operating exceeding 1st upper limit temperature, and memorize | stores the period. The controller 5 discharges a predetermined amount of water (hot water) in the hot water tank 9 to the outside when the operating period exceeding the first upper limit temperature exceeds a predetermined period. As a result, the precipitate due to the deposited impurities is discharged to the outside of the hot water tank 9. Since the predetermined period and the predetermined amount differ depending on the situation such as the component of the supplied water and the hot water supply usage state, the predetermined period and the predetermined amount may be set in the control unit 5 in advance.

  The control unit 5 may set the predetermined period described above according to the component of the supplied water. Examples of the water component herein include the hardness of water and the content of a metal component (for example, Ca) contained in water. For example, when the hardness of the supplied water is high, more impurities are deposited, so the predetermined period is shortened. In addition, when the hardness of the supplied water is small, the precipitation of impurities is relatively small, so the predetermined period is extended.

  In addition, you may make it the memory | storage part 40 memorize | store the hot water supply amount in the period which is drive | operating exceeding 1st upper limit temperature. The controller 5 estimates the amount of precipitated impurities from the amount of hot water supplied and the components of the water supplied to the hot water tank, and accumulates them in the storage unit 40. Then, the amount of water (hot water) to be discharged is set according to the amount of accumulated impurities deposited. By doing in this way, the quantity of the water to discharge | emit can be determined appropriately and it can be completed by discharge | emission of the minimum required water.

  For example, the water in the hot water tank 9 is discharged as follows. An opening / closing valve (not shown) is provided at the discharge port 23, and the controller 5 opens the opening / closing valve when discharging water. And after discharging | emitting a predetermined amount of water, the control part 5 closes an on-off valve. Here, the amount of discharged water is detected by, for example, a method of measuring the operation time of the on-off valve to the amount of water discharged per unit time that has been measured in advance, and taking their multipliers. In addition, when the water in the hot water tank 9 is discharged as described above, the water may be supplied from the city water inlet 21 in accordance with the amount of water discharged.

  Next, another hot water storage tank according to the present embodiment will be described with reference to FIG. FIG. 3 is a schematic view of another hot water storage tank according to the first embodiment. The hot water tank 9 shown in FIG. 3 differs from the hot water tank described above in that it has an inclined portion 30. Specifically, the bottom portion of the hot water tank 9 has an inclined portion 30 that is inclined toward the discharge port 23. By having such an inclined portion 30, impurities deposited in the hot water tank 9 are likely to gather near the discharge port 23, and the impurities accumulated in the hot water tank 9 can be discharged to the outside more efficiently. It is more preferable to provide the discharge port 23 at the lower end of the inclined portion 30. By doing in this way, the impurities accumulated in the hot water tank 9 can be discharged to the outside more efficiently.

(Embodiment 2)
FIG. 4 is a block diagram of a fuel cell power generation system according to Embodiment 2 of the present invention. In addition, the same code | symbol is attached | subjected to what makes the structure similar to Embodiment 1, and detailed description is abbreviate | omitted.

  In the present embodiment, the control unit 5 is further provided with an estimation unit 41. The control unit 5 has at least the same function as the control unit 5 described in the first embodiment. As described above, when the temperature of the water in the hot water tank 9 is operated so as to exceed the first upper limit temperature, the fuel cell 3 cannot be sufficiently cooled, the operating temperature becomes high, and the solid electrolyte membrane of the fuel cell 3 deteriorates. As a result, the life of the fuel cell 3 may be somewhat shortened. Therefore, the operation of the fuel cell 3 is controlled by estimating the lifetime by the estimation unit 41. Specifically, the lifetime is estimated as follows. The estimation unit 41 receives a current value and a voltage value of the power generated by the fuel cell 3. The estimation part 41 estimates the lifetime of the fuel cell 3 from the current-voltage characteristics calculated | required from these values, when the control part 5 drive | operates the temperature of the water in the hot water storage tank 9 below a 1st upper limit temperature.

  When the fuel cell 3 is operated under the same operating conditions, the performance of the fuel cell 3 is reduced with the passage of the operating time, and the voltage value is reduced. The same operating conditions mean that the amount of hydrogen-containing gas to be supplied, the dew point of the hydrogen-containing gas, the operating temperature, and the current value output from the fuel cell 3 are the same. When predicting the service life, the voltage value drop is measured / simulated in advance, and the operation time and voltage drop are tabulated. And the voltage value at the time of predicting the life is measured. From the voltage value and the above table, it is applied to which operating time the measured voltage value corresponds. Next, the difference from the operation time up to the voltage value set as the lifetime is calculated. In this way, the life of the fuel cell 3 can be estimated. What voltage value is determined as the life of the fuel cell 3 may be set by an individual device. For example, since a decrease in voltage value is synonymous with a decrease in power generation efficiency, the life of the fuel cell 3 may be set to be lower than the target power generation efficiency. Alternatively, when power generation is performed as much as the voltage decreases, the amount of hydrogen-containing gas required increases, so that the lifetime can be set in consideration of the hydrogen-containing gas generation capability of the fuel processor 1.

  Further, the estimation unit 41 estimates a change in the life of the fuel cell 3 due to a change in the power generation operation of the fuel cell 3 by the control unit 5. That is, the estimation unit 41 estimates the influence on the life due to the operation of the water in the hot water tank 9 above the first upper limit temperature as a change in the life. For example, data indicating how much the life per operating unit time is shortened by operating above the first upper limit temperature is retained, and the shortening of the life is estimated from the time of operation exceeding the first upper limit temperature. be able to.

  The storage unit 40 holds the life value of the fuel cell 3 estimated by the estimation unit 41. The estimation unit 41 updates the life value of the fuel cell 3 held in the storage unit 40 when the estimated life value of the fuel cell 3 changes.

  For example, it is necessary to guarantee a lifetime of about 10 years for a household fuel cell power generation system. Therefore, the fuel cell 3 is designed to have a life of 10 years or longer even when operating in normal operation. By holding the lifetime value thus shortened in the storage unit 40, for example, it is possible to limit the operation exceeding the first upper limit temperature. This ensures a lifetime of about 10 years.

  On the other hand, when it is often used at a relatively light load in normal operation, there may be a situation where the life of the fuel cell 3 far exceeds 10 years. Thus, when there is room in the life, the control unit 5 can actively operate above the first upper limit temperature. That is, the control unit 5 compares the guaranteed lifetime value of the fuel cell 3 preset and stored in the storage unit 40 with the actually estimated lifetime value of the fuel cell 3, and according to the comparison result. The temperature of the hot water tank can be controlled. In this way, it is possible to flexibly cope with fluctuations in the load 11 while ensuring a guaranteed life.

  As described above, in the fuel cell power generation system of the present invention, when the temperature of the water in the hot water storage tank exceeds the predetermined first upper limit temperature and the operation is continued, the hot water storage water is discharged by discharging the water in the hot water storage tank. Drain the sediment in the tank. As a result, problems in the operation of the fuel cell can be prevented, and convenience can be improved. The fuel cell power generation system according to the present invention is particularly useful as a system for stably supplying electric power at home.

DESCRIPTION OF SYMBOLS 1 Fuel processor 3,103 Fuel cell 5 Control part 7,107 Heat exchanger 9,109 Hot water tank 10,110 Inverter 11 Load 12,112 Fuel cell cooling water circulation path 13,113 Hot water tank water circulation path 13a Hot water tank water circulation path inlet 13b Hot water tank water circulation path exit 21 City water inlet 22 Hot water supply port 23 Discharge port 24 Temperature detection unit 30 Inclination unit 40 Storage unit 41 Estimation unit

Claims (14)

A fuel cell;
A hot water storage tank that collects and stores heat generated from the fuel cell with water, and has a water discharge port provided near the bottom, and a temperature detection unit that detects the temperature of the water;
A control unit,
A first upper limit temperature of water in the hot water tank is provided in the control unit in advance,
The controller is
When the temperature detected by the temperature detection unit exceeds the first upper limit temperature and the operation of the fuel cell is continued,
A fuel cell power generation system for discharging water in the hot water storage tank from the discharge port. The fuel cell power generation system according to claim 1, wherein the deposit in the hot water storage tank is discharged by discharging water in the hot water storage tank from the discharge port. 2. The fuel cell power generation system according to claim 1, wherein the hot water storage tank includes a water outlet to the outside of the hot water tank in the vicinity of the upper part and an inlet of water to the inside of the hot water tank in the vicinity of the bottom part. Further, a second upper limit temperature is provided in advance in the control unit for the temperature of the water in the hot water tank,
The fuel cell power generation system according to any one of claims 1 to 3, wherein the control unit stops the operation of the fuel cell when the temperature detected by the temperature detection unit exceeds the second upper limit temperature. 5. The fuel cell power generation system according to claim 1, wherein the first upper limit temperature is a temperature at which the precipitate is deposited from water in the hot water storage tank. The fuel cell power generation system according to any one of claims 1 to 5, wherein the second upper limit temperature is an operation limit temperature for operating the fuel cell. The control unit further includes a storage unit that measures and stores a period during which the fuel cell is operated above the first upper limit temperature,
The fuel cell power generation system according to claim 1, wherein the control unit discharges the water from the discharge port when the period reaches a predetermined period. The storage unit measures and stores the amount of hot water supplied from the hot water storage tank during the predetermined period,
The fuel cell power generation system according to claim 7, wherein the control unit sets a discharge amount of the water to be discharged from the hot water supply amount and a component of water supplied into the hot water storage tank. The fuel cell power generation system according to claim 7, wherein the control unit sets the predetermined period from a component of supplied water. The fuel cell power generation system according to claim 8 or 9, wherein the water component includes at least one of hardness of water and an amount of a metal component contained in water. The fuel cell power generation system according to any one of claims 1 to 10, wherein the hot water storage tank has an inclined portion inclined downward toward the discharge port. The control unit estimates the life of the fuel cell from the current-voltage characteristics of the fuel cell while operating the fuel cell at the first upper limit temperature or lower,
2. The fuel cell power generation system according to claim 1, further comprising an estimation unit configured to estimate a change in a life of the fuel cell, which is generated when the fuel cell is operated above the first upper limit temperature. The control unit further includes a storage unit that holds a life value of the fuel cell estimated by the estimation unit,
The fuel cell power generation system according to claim 12, wherein the estimation unit updates the value of the life of the fuel cell held in the storage unit when the estimated value of the life of the fuel cell changes. The control unit further includes a storage unit that holds a preset value of the guaranteed lifetime of the fuel cell,
The said control part compares the value of the guaranteed lifetime of the said fuel cell memorize | stored in the said memory | storage part with the value of the lifetime of the said fuel cell, The said upper limit temperature is changed according to the comparison result. Fuel cell power generation system.

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