JP2016143624A - Fuel battery power generation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a package type fuel battery power generation device capable of detecting leakage of flammable gas when leakage of flammable gas occurs in a casing, and reducing power consumption of a ventilation fan.SOLUTION: In a case where hydrogen gas as flammable gas is detected in a casing of a fuel battery power generation device, when a detected concentration value is less than a quarter of an explosion lower limit (LEL), a ventilation fan is actuated at a predetermined number of revolutions according to the detected concentration value. When the concentration value of hydrogen which is detected after the ventilation fan is actuated is equal to 0%, the actuation of the fan is stopped. When the concentration value of hydrogen detected after the ventilation fan is actuated continuously indicates 24% LEL for a fixed time, the power generation of a fuel battery main body is stopped.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a package type fuel cell power generator in which a fuel cell main body is housed in a casing together with other devices and pipes. In particular, the fuel cell main body detects a combustible gas in the casing and the inside of the casing by a ventilation fan. The present invention relates to a fuel cell power generator that is ventilated.

  2. Description of the Related Art Conventionally, in a package type fuel cell power generator, a ventilation fan is attached to an exhaust port provided in a casing to drive the fan in order to prevent the inside of the casing from being overheated by heat generated from equipment housed in the casing. In this way, the inside of the casing is ventilated. Furthermore, in the unlikely event that a flammable gas leaks from the inside of the casing, a flammable gas detector is installed inside the casing to prevent the explosion due to the leaked flammable gas. There has been proposed an apparatus for controlling the ventilation fan by discriminating the combustible gas concentration inside the casing (Patent Document 1). In the device disclosed in Patent Document 1, a fuel cell main body, a fuel processing device, a control device, and piping are accommodated in a package (casing) having an intake port and an exhaust port, and a ventilation fan is provided at the exhaust port of the package. And a combustible gas detector, respectively, allow ventilation in the package and detection of leakage of combustible gas.

JP-A-11-86891

  In this package type power generator, when a flammable gas leaks, the flammable gas is guided to the exhaust port side by the ventilation fan, and is detected by the flammable gas detector provided near the vent port. Based on this, a control operation for increasing the rotational speed of the ventilation fan is performed. By this operation, the ventilation amount by the ventilation fan is increased, and the effect of suppressing the concentration of the combustible gas in the package below the lower explosion limit can be obtained. In order to reliably detect the leakage of flammable gas in such a device, it is desirable to maintain the air flow in the package in a good state, and for this purpose, the ventilation fan is always operated to exceed a certain amount. It was necessary to ensure the ventilation airflow at all times. When the ventilation fan is always operated, there is a problem that power consumption increases, and noise due to the operation of the ventilation fan is always generated, and the life of the fan is reduced. If the device is installed in a salt damage area, a salt damage prevention air filter is installed at the intake port that takes in outside air so that salt is not sucked into the package. There was a problem that the air filter clogged quickly. In addition, since the fuel cell body and the fuel reformer require a higher temperature than the outside air temperature, if the ventilation fan is operated at all times, the internal temperature of the package will drop when the outside air temperature is low. As a result, there is a problem that the efficiency is lowered or the original sufficient ability cannot be exhibited.

  The present invention has been made in view of the above-described problems, and it is possible to detect when a flammable gas leaks inside the casing and to reduce the power consumption of the ventilation fan. It is an object of the present invention to provide a package-type fuel cell power generator that can be used.

  (1) In order to achieve the above object, the present invention provides a fuel cell power generation apparatus having a fuel cell main body, which is supplied with air and fuel to generate electric power in a casing, and is supplied as fuel to the fuel cell main body. A hydrogen reformer for generating hydrogen gas, a storage tank for storing the hydrogen gas generated by the fuel reformer, a hydrogen detection means for detecting the concentration of hydrogen gas inside the casing, and the outside air into the casing An intake port for taking in air, an exhaust port for discharging the air inside the casing to the outside of the casing, a ventilation fan for circulating the air inside the casing, a control unit for controlling the operation of the entire fuel cell, and an explosion of hydrogen A storage unit for storing a data table in which a concentration range less than a quarter of the lower limit is divided into a plurality of ranges and the rotation speed of the ventilation fan is set for each divided range; When the concentration value of hydrogen in the casing detected by the hydrogen detection means is less than one quarter of the lower explosion limit, the detected concentration value is included by referring to the data table stored in the storage unit. The ventilation fan is operated at a rotation speed corresponding to the range to be detected, and the operation of the ventilation fan is stopped when the concentration value of hydrogen detected after the ventilation fan is operated becomes 0% LEL. A fuel cell power generator is proposed.

  (2) In the proposed fuel cell power generator, the data table stored in the storage unit when the concentration value of hydrogen in the casing detected by the hydrogen detection means is less than a quarter of the lower explosion limit. , The ventilation fan is operated at a rotational speed corresponding to the range in which the detected concentration value is included, and the concentration value of hydrogen detected after the ventilation fan is operated is continuously 24% for a certain period of time. When LEL is indicated, it is desirable to stop the power generation operation of the fuel cell body.

  (3) In addition, a plurality of the ventilation fans and a means for detecting whether or not a failure has occurred in each of the ventilation fans are provided. When a failure occurs in any one of the plurality of ventilation fans, the remaining normal ventilation It is desirable to stop the power generation operation of the fuel cell main body when the operation continues with the fans and a failure occurs in all of the plurality of ventilation fans.

  (1) According to the proposed invention, when hydrogen gas, which is a flammable gas, is detected in the casing of the fuel cell power generator, the detected concentration value is a quarter of the lower explosion limit (LEL). If the concentration value of hydrogen detected below is 0%, the ventilation fan is operated at a predetermined number of revolutions according to the detected concentration value and the ventilation fan is operated and then the detected hydrogen concentration value is 0%. Stop fan operation. Thus, when the hydrogen detection means detects hydrogen in the casing, the fan is operated to ventilate the air in the casing, and if no hydrogen is detected in the casing after the ventilation is performed, the fan is stopped. Therefore, it is not necessary to operate the ventilation fan at all times, and since the ventilation operation is performed only when hydrogen is detected in the casing, the power consumed by the ventilation fan is greatly reduced, and at the same time the life of the ventilation fan is prevented from being reduced. can do. In addition, since the ventilation operation in the casing is minimized, the frequency of cleaning the dust filter attached to the intake port and the frequency of replacing the salt damage prevention air filter can be reduced. In addition, when performing temperature management as a fuel cell, it is possible to improve power generation efficiency because unnecessary ventilation is not performed as much as possible from the viewpoint of the power generation function.

  (2) According to the proposed invention, when the hydrogen detection means detects hydrogen in the casing, the ventilation fan is operated to ventilate the air in the casing, and then hydrogen is detected again while ventilating, As a result, when the detected hydrogen concentration value continuously indicates 24% LEL corresponding to approximately one fourth of the lower explosion limit for a certain period of time, the power generation operation of the fuel cell body is stopped. This normally minimizes the operation of the ventilation fan, while ventilating if hydrogen is detected in the casing and still detecting hydrogen leakage if 24% LEL hydrogen is detected again. Since the operation of the fuel cell main body is stopped when it is determined that the hydrogen has occurred, hydrogen leakage can be reliably detected while saving power and improving the life of the ventilation fan.

  (3) According to the proposed invention, a plurality of ventilation fans are provided, and when a failure occurs in any of the fans, ventilation is performed with a normal fan, and all of the plurality of fans fail. When this occurs, the operation of the fuel cell main body is stopped, so that the reliability of the hydrogen leak detection operation can be improved. In addition, if all ventilation fans break down and the ventilation function is lost, the fuel cell body will stop operating before hydrogen leaks, so safety measures must be taken before entering a dangerous state. It becomes possible.

It is explanatory drawing which shows the whole structure of the fuel cell power generation apparatus which concerns on an Example of this invention. It is a flowchart which shows the detection operation | movement of hydrogen, and the operation | movement of the ventilation fan at the time of detecting hydrogen. It is a data table which shows the relationship between the hydrogen concentration value detected with the hydrogen detection means, and the rotation speed of a ventilation fan.

  Preferred embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an explanatory diagram showing the overall configuration of a fuel cell power generator according to an embodiment of the present invention. Reference numeral 1 denotes a casing that forms the outer shell of the fuel cell power generation device. Inside the casing 1 is a fuel cell body 2, a fuel reformer 3, and a methanol aqueous solution that serves as fuel for generating hydrogen in the fuel reformer 3. A fuel tank 4 for storing hydrogen, a storage tank 5 for storing hydrogen gas generated by the fuel reformer 3, a blower 6 for supplying air to the fuel cell main body 2, a hydrogen detecting means 7, a temperature sensor 8, and for ventilating the inside of the casing A ventilation fan 9, a storage unit 10 for storing data for controlling rotation of the ventilation fan, a control unit 11 for controlling the operation of the entire fuel cell power generator, and a ventilation fan failure detection unit 16 for detecting whether or not a failure has occurred in the ventilation fan , Respectively. And among these, the control part 11 and the memory | storage part 10 are isolated by the partition 17 in the casing, and are accommodated in another space separated from the other apparatus. The casing 1 is provided with an intake port 12 and an exhaust port 13, and a salt damage prevention air filter 14 is attached to the intake port 12. When the ventilation fan 9 is operated, outside air flows into the casing from the air inlet 12 via the salt damage prevention air filter 14, and after the inside of the casing is ventilated, the air is discharged out of the casing through the air outlet 13. Yes. At that time, since the outside air is introduced through the salt damage prevention air filter 14, even if sea salt particles or salt water mist causing the salt damage is contained in the outside air, the air from which the air has been removed is taken into the casing. The occurrence of salt damage is prevented. The salt damage prevention air filter 14 has a function of removing not only sea salt particles and salt water mist but also oil mist and dust. The ventilation fan 9 is configured by a set of two fan units, and failure detection is performed by the ventilation fan failure detection unit 16 for each individual fan unit. If a failure occurs in one of the two, the ventilation operation is performed with the remaining normal fans, and if both fan units fail, the subsequent ventilation operation cannot be performed. Is stopped.

  The fuel reformer 3 mixes methanol and steam supplied from the fuel tank 4 and reacts them at a temperature of about 150 to 300 ° C. using a catalyst to decompose the methanol into hydrogen gas and carbon dioxide. . Although not shown in the figure, a solenoid valve and a fuel pump are attached to a pipe line connecting the fuel tank 4 and the fuel reformer 3, and the control unit 11 controls the fuel tank 4 to the fuel reformer 3. An aqueous methanol solution is supplied.

  The fuel cell main body 2 is formed by stacking a large number of cells with separators in between, each unit being a cell composed of a fuel electrode, an electrolyte, and an air electrode. The fuel electrode and air electrode have a structure that allows gas to pass through. Hydrogen gas stored in the storage tank 5 is supplied to the fuel electrode, and air is supplied from the blower 6 to the air electrode. become. Since the electrolyte only allows ions to pass, the electrons that were cut off when the hydrogen was ionized moved out of the electrolyte, and the hydrogen ions that moved inside the electrolyte were transferred to the opposite air electrode and the outer circuit. It reacts with the electrons that flowed back and becomes water. Power generation is performed in this way, and the electric power generated by direct current is converted into alternating current by the direct current / alternating current inverter 15 and supplied to an external load.

  The fuel reformer 3 and the fuel cell main body 2 require a high temperature to maintain the above-described reaction and maintain an efficient operation state, while the ambient temperature in the casing is excessive. In order to suppress the rise, the outer surfaces of the fuel reformer 3 and the fuel cell main body 2 are covered with a thick heat insulating material. However, since generation of heat dissipated through the heat insulating material cannot be avoided, cooling is performed by ventilating the inside of the casing by the ventilation fan 9. The control unit 11 controls the number of rotations of the ventilation fan 9 based on the temperature in the casing detected by the temperature sensor 8 and adjusts the ventilation air volume to keep the device housed in the casing at a temperature at which it can operate normally. I am doing so. As a result, the ambient temperature in the casing is prevented from excessively rising, and the temperature of the fuel reforming device 3, the fuel cell main body 2, and the pipe connecting the devices is prevented from being excessively lowered from the temperature suitable for operation. . The storage unit 10 stores the relationship between the temperature detected by the temperature sensor 8 and the rotational speed of the ventilation fan 9 as a data table. The control unit 11 controls the drive of the ventilation fan 9 according to this table.

  The hydrogen detection means 7 detects the presence and concentration of hydrogen contained in the atmosphere in the casing. When the hydrogen detection means 7 detects hydrogen, the control unit 11 sets the detected hydrogen concentration value. The ventilation fan 9 is driven at a corresponding number of revolutions to perform forced ventilation in the casing. The storage unit 10 stores a relationship between the hydrogen concentration value detected by the hydrogen detection means 7 and the rotation speed of the ventilation fan 9 as a data table, and the control unit 11 performs drive control of the ventilation fan 9 according to this table. is there. The IEC standard stipulates that the fuel cell power generation system must ensure that the concentration of combustible gas in the exhaust of the ventilator does not exceed 25% LEL, and is most likely to leak as a fuel cell power generation device. In the case of hydrogen, which is a highly flammable gas, the lower explosion limit is 4 vol%, so that 4 vol% = 100% LEL. Therefore, the concentration of hydrogen gas contained in the atmosphere in the casing is 25% LEL. It must be kept within a certain 1% by volume. Therefore, when the hydrogen detection means 7 detects hydrogen, the ventilation fan 9 is driven to discharge the hydrogen in the casing. However, since the hydrogen gas detector constituting the hydrogen detection means 7 is responsive to flammable gases other than hydrogen due to its structure, various types of outdoor exhaust gas are used when detection is performed within a range of 1 vol%. There is a possibility of erroneous detection in response to gas or the like. Therefore, when hydrogen is detected in the casing, the ventilation fan 9 is driven at a rotational speed corresponding to the detected hydrogen concentration value, and then the hydrogen concentration detected by the hydrogen detection means 7 becomes 0% LEL. In this case, it is determined that no hydrogen leak has occurred in the casing, and the operation of stopping the operation of the ventilation fan is performed.

  Next, the hydrogen detection operation and the operation of the ventilation fan when hydrogen is detected will be described based on the flowchart of FIG. When hydrogen is detected by the hydrogen detection means 7 (S1), it is determined whether the detected hydrogen concentration value is within the range of 1% LEL to 6% LEL (S2). In the case of a low value in the range of 1% LEL to 6% LEL, the possibility of false detection is considered in addition to the low urgency, and the ventilation operation in the casing is minimized as far as there is no danger. From the idea that it is desired to suppress it to the limit, the ventilation fan is not operated and the stopped state is maintained (S3). Of course, the ventilation fan maintains the stopped state even when hydrogen is not detected in S1 (S3). Next, it is determined whether the value of the hydrogen concentration detected in S1 is within the range of 7% LEL to 12% LEL (S4). If the value is within the range of 7% LEL to 12% LEL, The ventilation fan is operated at a low rotational speed (S5). Subsequently, it is determined whether the value of the hydrogen concentration detected in S1 is within the range of 13% LEL to 18% LEL (S6). If the value is within the range of 13% LEL to 18% LEL, The ventilation fan is operated at a medium speed higher than the low speed of S5 (S7). Subsequently, it is determined whether the value of the hydrogen concentration detected in S1 is within the range of 19% LEL to 24% LEL (S8). If the value is within the range of 19% LEL to 24% LEL, The ventilation fan is operated at a high speed with a higher rotational speed than the low speed of S5 and the medium speed of S7 (S9). After the ventilation fan is operated at a high speed in S9, it is determined whether the detected hydrogen concentration value shows a numerical value of 24% LEL for a certain period of time (S10). Keeps the ventilation fan operating at high speed. In S10, if the value of 24% LEL is detected continuously for a certain period of time, it is determined that hydrogen leakage has occurred in the casing, and the operation of the fuel cell body 2 is stopped. When the hydrogen concentration value exceeds 24% LEL in S8, the operation of the fuel cell main body 2 is stopped as a safety measure. Here, in this embodiment, 5 seconds is set as the fixed time for the determination in S10.

  Next, among the data tables stored in the storage unit 10, a data table showing the relationship between the hydrogen concentration value detected by the hydrogen detection means and the rotation speed of the ventilation fan will be described with reference to FIG. This data table defines the relationship between the hydrogen concentration% LEL, the corresponding hydrogen concentration vol%, and the movement of the ventilation fan at these concentrations. That is, the operation of the ventilation fan is stopped in the range of hydrogen concentration 0 to 6% LEL (0 to 0.24 vol%), and in the range of hydrogen concentration 7 to 12% LEL (0.28 to 0.48 vol%). The ventilation fan is operated at low speed, and in the range of hydrogen concentration 13-18% LEL (0.52-0.72 vol%), the ventilation fan is operated at medium speed, hydrogen concentration 19-24% LEL (0.76-0 .96 vol%) specifies that the ventilation fan operates at high speed. As described above, the presence / absence of hydrogen gas and the hydrogen concentration are detected in the casing of the fuel cell power generation device, and when the hydrogen gas is detected, the rotation speed of the ventilation fan is switched according to the concentration to drive, Thereafter, the ventilation fan continues to be driven until hydrogen gas is not detected in the casing or the concentration becomes extremely low. If the detected concentration value continues to show 24% LEL even when the ventilation fan is driven, the operation of the fuel cell main body is stopped. This ensures safety while minimizing the operation of the ventilation fan.

DESCRIPTION OF SYMBOLS 1 Casing 2 Fuel cell main body 3 Fuel reformer 4 Fuel tank 5 Storage tank 6 Blower 7 Hydrogen detection means 8 Temperature sensor 9 Ventilation fan 10 Memory | storage part 11 Control part 12 Intake port 13 Exhaust port 16 Ventilation fan failure detection part

Claims (3)

In a fuel cell power generation apparatus provided with a fuel cell body that generates electric power by supplying air and fuel in a casing,
A fuel reformer that generates hydrogen gas supplied as fuel to the fuel cell body, a storage tank that stores the hydrogen gas generated by the fuel reformer, and a hydrogen detector that detects the concentration of hydrogen gas inside the casing Means, an intake port for taking outside air into the casing, an exhaust port for discharging the air inside the casing to the outside of the casing, a ventilation fan for circulating the air inside the casing, and the operation of the entire fuel cell A control unit for controlling, and a storage unit for storing a data table in which a concentration range less than a quarter of the lower explosion limit of hydrogen is divided into a plurality and the number of rotations of the ventilation fan is set for each divided range ,
When the concentration value of hydrogen inside the casing detected by the hydrogen detection means is less than a quarter of the lower explosion limit, the detected concentration value is included by referring to the data table stored in the storage unit. The ventilation fan is operated at a rotation speed corresponding to a range, and the operation of the ventilation fan is stopped when the concentration value of hydrogen detected after the ventilation fan is operated becomes 0% LEL. Fuel cell power generator.   2. The fuel cell power generator according to claim 1, wherein when the concentration value of hydrogen inside the casing detected by the hydrogen detector is less than a quarter of the lower explosion limit, a data table stored in the storage unit is stored. The ventilation fan is operated at a rotation speed corresponding to a range including the detected concentration value, and the concentration value of hydrogen detected after the ventilation fan is operated is continuously 24% LEL for a certain period of time. , The fuel cell generator stops the power generation operation of the fuel cell main body.   3. The fuel cell power generator according to claim 1, comprising a plurality of the ventilation fans and means for detecting whether or not a failure has occurred in each of the ventilation fans. When a failure occurs, the fuel cell power generation is characterized in that the operation is continued with the remaining normal ventilation fans, and the power generation operation of the fuel cell main body is stopped when a failure occurs in all the fans of the plurality of ventilation fans. apparatus.

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