JP4399553B2 - Fuel cell system - Google Patents

Description

  The present invention relates to a fuel cell system, and more particularly to a fuel cell in which commercial gas that has passed through a meter having a function of shutting off the flow of gas when a predetermined flow rate of gas flows for a certain period of time is reformed and introduced into fuel gas. The present invention relates to a fuel cell system provided.

  A fuel cell system that is a power generation system equipped with a fuel cell that can significantly reduce emissions of harmful gases such as carbon dioxide and nitrogen oxides, which cause global warming, in recent years, with increasing interest in environmental conservation. Is attracting attention. In general, a fuel cell system reforms a raw material fuel in a reformer to generate a fuel gas rich in hydrogen, and generates electric power by an electrochemical reaction between the generated fuel gas and an oxidant gas containing oxygen. System. As the raw material fuel, various raw material fuels such as city gas, LPG, digestion gas, methanol, GTL (Gas to Liquid) and kerosene can be used. In particular, a fuel cell system is installed at home as a distributed power source. Sometimes, commercial gas such as city gas is used from the viewpoint of availability.

  By the way, when receiving supply of commercial gas, from the viewpoint of safety, there is a case where the supply of gas is received through a meter having a function of blocking the flow of gas when a predetermined flow rate of gas flows for a certain time or more. This is particularly noticeable when supplying commercial gas at home. A meter having such a protection function is generally called a microcomputer meter. For example, when the gas flowed unnaturally, such as when the rubber tube is removed, or when the gas usage time is longer than necessary, such as leaving the bath, the micrometer will crack. It is a meter that has a function of automatically shutting off the gas flow when a predetermined flow rate of gas flows for a certain period of time or more, such as when a certain gas leaks and a minute amount of gas continues to flow for 30 days or more.

  When using commercial gas as a raw material for fuel gas, the fuel cell may also introduce gas that has passed through the microcomputer meter into the reformer. In general, the gas is supplied via the microcomputer meter at home. Is.

  However, when there is a constant power load, if a commercial gas is introduced into the reformer in accordance with the operation of the fuel cell in order to always operate the fuel cell, a gas having a predetermined flow rate flows for a certain time or more. Even if it is normal operation, the microcomputer meter may mistakenly recognize that there is a gas leak and shut off the gas flow. When the flow of gas introduced into the reformer is interrupted, the production of fuel gas is stopped, and the fuel cell from which the supply of fuel gas is cut off is also stopped. Although it is difficult to disable the protection function of the microcomputer meter from the viewpoint of safety, the fuel cell consumes fuel that is not used for power generation such as preheating at the time of starting and stopping. When the operation is stopped, the energy loss of the fuel cell system increases.

  In view of the above-described problems, an object of the present invention is to provide a fuel cell system capable of continuously operating without suppressing a gas flow interruption without invalidating a protection function of a microcomputer meter.

  In order to achieve the above object, the fuel cell system according to claim 1 has a function of interrupting the flow of gas when a predetermined flow rate of gas flows for a predetermined time or more as shown in FIG. The reformer 31 that introduces the commercial gas G that has passed through the meter 2 and reforms the commercial gas G to generate the fuel gas h rich in hydrogen, and the heat generated by introducing the fuel gas h and electrochemical reaction to generate heat The fuel cell unit 3 having the fuel cell 32 that generates the gas; and the fluctuation of the flow rate of the commercial gas G that has passed through the meter 2 until a predetermined time corresponding to the flow rate of the commercial gas G that has passed through the meter 2 elapses. A control device 9 is provided that varies the flow rate of the commercial gas G passing through the meter 2 in accordance with the fluctuation of the generated current generated by the fuel cell 32 when it is within the predetermined width.

  With this configuration, the fuel cell generates power when fluctuations in the flow rate of the commercial gas that has passed through the meter are within a predetermined range until the predetermined time corresponding to the flow rate of the commercial gas that has passed through the meter elapses. Since the flow rate of the commercial gas passing through the meter is fluctuated more than the predetermined width as the generated current is fluctuated, it can be avoided that the function of blocking the gas flow provided in the meter is activated, The fuel cell can be operated continuously. The “commercial gas” refers to a gas that is supplied from outside by paying consideration such as city gas and propane gas. The “predetermined time” is the time from when the gas begins to flow to the meter until the function of shutting off the gas flow of the meter is activated, and the “predetermined width” is the time required to interrupt the measurement for the predetermined time. This is the range of fluctuation of the gas flow rate.

  Further, in the fuel cell system according to claim 2, for example, as shown in FIG. 1, in the fuel cell system according to claim 1, the fluctuation of the generated current is an increase in the generated current; At least one of a battery 61 for storing surplus power, a heating element 62 that converts heat into heat, and a wattmeter 39 that measures the reverse power flow to the commercial power source is provided.

  If comprised in this way, since it has at least one of the battery which accumulates electric power which becomes surplus by the generated power generation current, the heating element which converts it into heat, and the wattmeter which measures it as it reversely flows into the commercial power source In order to avoid the function of blocking the gas flow provided in the meter from being activated, it is possible to effectively use the current increased as a result of increasing the flow rate of the commercial gas by a predetermined width or more.

  Moreover, the fuel cell system according to claim 3 is the fuel cell system according to claim 1 or 2, for example, as shown in FIG. 1; instead of the control device, commercial gas that has passed through the meter 2 When the flow rate of the commercial gas G introduced into the reformer 31 is within a predetermined range until a predetermined time corresponding to the flow rate of G passes, the generated current generated by the fuel cell 32 is changed. And a control device 9 that varies the flow rate of the commercial gas G introduced into the reforming device 31 by the predetermined width or more.

  With this configuration, when the change in the flow rate of the commercial gas introduced into the reformer is within a predetermined range until a predetermined time corresponding to the flow rate of the commercial gas that has passed through the meter has elapsed, Since the flow rate of the commercial gas introduced into the reformer is fluctuated by more than a predetermined width as the generated current generated by the battery is changed, the function of shutting off the gas flow provided in the meter is avoided. The fuel cell can be operated continuously.

  Further, as shown in FIG. 1, for example, in the fuel cell system according to claim 4, in the fuel cell system according to claim 3, the heat generated in the fuel cell 32 is stored using hot water as a medium, and the commercial gas G At least one of the first auxiliary heater 42A that introduces and burns and heats the hot water u and the second auxiliary heater 42B that introduces and burns commercial gas G and introduces and burns from outside and heats the circulating hot water w is heated. The hot water storage unit 4 having; the flow rate of the commercial gas G introduced into the reforming device 31 until the predetermined time corresponding to the flow rate of the commercial gas G passing through the meter 2 passes, When the fluctuation of the flow rate of the commercial gas G in total with the flow rate of the commercial gas G introduced into at least one of the first auxiliary heater 42A and the second auxiliary heater 42B is within a predetermined range, the fuel cell 32 To generate electricity And a control unit 9 for varying said predetermined constant width over the flow rate of the commercial gas G total along with the varying Denden flow.

  With this configuration, the flow rate of the commercial gas introduced into the reformer, the first auxiliary heater, and the second auxiliary heating until a predetermined time corresponding to the flow rate of the commercial gas that has passed through the meter elapses. When the fluctuation of the total commercial gas flow rate with the flow rate of the commercial gas introduced into at least one of the reactors is within a predetermined range, the total commercial gas is changed along with the fluctuation of the power generation current generated by the fuel cell. Therefore, it is possible to avoid the function of blocking the gas flow provided in the meter from being operated, and the fuel cell can be operated continuously. Note that the flow rate of the commercial gas introduced into the reforming apparatus and at least one of the first auxiliary heater and the second auxiliary heater until a predetermined time corresponding to the flow rate of the commercial gas that has passed through the meter elapses. When the fluctuation of the total commercial gas flow rate with respect to the flow rate of the commercial gas introduced into is within a predetermined range, the commercial gas is introduced into the auxiliary heater to change the total commercial gas flow rate by more than the predetermined width. May be.

  According to the present invention, the flow rate of the commercial gas is fluctuated by a predetermined width or more as the generated current generated by the fuel cell is fluctuated, so that the function of blocking the gas flow provided in the meter is avoided. Therefore, the fuel cell system can be operated continuously.

  Embodiments of the present invention will be described below with reference to the drawings. In each figure, the same or equivalent devices are denoted by the same reference numerals, and redundant description is omitted. In the figure, a broken line represents a control signal.

  A configuration of a fuel cell system 1 according to an embodiment of the present invention will be described with reference to FIG. FIG. 1 is a block diagram illustrating a fuel cell system 1 according to an embodiment of the present invention. The fuel cell system 1 includes a fuel cell unit 3, a hot water storage unit 4, a power consumption meter 39, a control device 9, and a battery 61 that stores electric power.

  The fuel cell unit 3 introduces a reformer 31 that introduces a commercial gas G to reform and generates a fuel gas h rich in hydrogen, and introduces a fuel gas h and an oxidant gas a containing oxygen into an electrochemical system. And a fuel cell 32 that generates water and heat by a natural reaction.

  The reformer 31 has a combustion section 31a for obtaining reforming heat necessary for reforming. The reformer 31 has a nozzle for introducing the commercial gas G, a nozzle for introducing the modifier s, and a nozzle for deriving the fuel gas h generated by the reforming reaction. Further, the combustion section 31 a has a nozzle for introducing the anode off gas p discharged from the fuel cell 32. A nozzle for deriving the fuel gas h generated by the reformer 31 is connected to the fuel electrode 32 a of the fuel cell 32. A pipe 53 is connected to the nozzle for introducing the commercial gas G, and a gas flow meter 37 and a flow rate adjustment valve 38 are arranged in the pipe 53. The pipe 53 is connected to a pipe 52 outside the fuel cell unit 3, and the meter 2 is arranged in the pipe 52.

  A signal cable is laid between the gas flow meter 37 and the control device 9. The gas flow meter 37 is configured to measure the flow rate of the gas G introduced into the reforming device 31 of the fuel cell unit 3 and transmit the measured flow rate of the gas G to the control device 9 as a signal. Yes.

  The flow rate adjusting valve 38 is an electric two-way valve, and is configured to adjust the flow rate of the gas G introduced into the reformer 31 and to block the flow of the gas G. A signal cable is laid between the flow regulating valve 38 and the control device 9. The flow rate adjustment valve 38 can control the operation and stop of the fuel cell 32 by receiving the signal from the control device 9 and controlling the introduction of the gas G to the reforming device 31 by opening and closing the valve. It is configured to be able to.

  The meter 2 has a function (safety device) that cuts off the flow of the gas G when a predetermined flow rate of gas flows for a predetermined time or more, and is sometimes called a microcomputer meter. For example, if the gas flows unnaturally in a large amount, such as when the rubber tube is removed, or if the gas usage time is longer than necessary, such as leaving a bath, the meter 2 will crack. As in the case where a certain gas leaks and a minute amount of gas continues to flow, the gas G is automatically shut off when a predetermined flow rate of gas continues to flow for a certain period of time. The time required from the start of the flow of the gas G to the meter 2 until the flow is cut off depends on the flow rate of the gas G flowing through the meter 2. For example, as shown in FIG. 2, when the flow rate of the gas G flowing through the meter 2 is relatively high, the time required to cut off the flow of the gas G is relatively short, and the flow rate of the gas G flowing through the meter 2 is relatively low. When the amount is small, it takes a relatively long time to block the flow of the gas G. The relationship between the flow rate of the gas G and the time required to shut off the flow of the gas G corresponds to “a predetermined time corresponding to the flow rate of the commercial gas that has passed through the meter”. Further, the measurement for a predetermined time is interrupted when the fluctuation of the gas flow rate exceeds a predetermined amount, and is measured again. The fluctuation range of the gas flow rate necessary for interrupting the measurement for a predetermined time varies depending on the meter to be used. Typically, the flow rate of the gas G every certain time is integrated, and the integrated amount of the gas G is the immediately preceding amount. The measurement is interrupted for a predetermined time if it fluctuates by a certain amount or more compared to the integrated amount. The fluctuation range of the gas flow rate necessary for interrupting the measurement for the predetermined time corresponds to the “predetermined width”. A signal cable is laid between the meter 2 and the control device 9 so that the flow rate of the gas G passing through the meter 2 can be transmitted to the control device 9 as a signal. The gas G that has passed through the meter 2 is supplied to the reformer 31, auxiliary heaters 42A and 42B, a gas appliance 99 such as a gas stove outside the system, and the like.

  The fuel cell 32 is a polymer electrolyte fuel cell, and includes a fuel electrode 32a, an air electrode 32b, and a cooling water channel 32c. The fuel electrode 32a is provided with a nozzle for introducing the fuel gas h generated and introduced by the reformer 31, and a nozzle for discharging the anode off gas p. In the air electrode 32b, a nozzle for introducing the oxidant gas a delivered from the blower 88 and a nozzle for discharging the cathode off gas q are arranged. In the cooling water flow path 32c, a nozzle for introducing the cooling water c as a cooling fluid pumped by the circulation pump 35 and a nozzle for deriving the cooling water c are arranged.

  A signal cable is laid between the blower 88 that sends the oxidant gas a to the air electrode 32 b and the control device 9. The blower 88 receives a signal from the control device 9, adjusts the rotational speed of the rotor blade, and sends the oxidant gas a having a flow rate corresponding to the flow rate of the fuel gas h sent to the fuel electrode 32a to the air electrode 32b. It is configured.

  The fuel cell unit 3 including the reformer 31 and the fuel cell 32 further includes an inverter 33 that converts the direct current generated by the fuel cell 32 into an alternating current, and the heat generated in the fuel cell 32 is stored in the hot water storage unit 4. A heat exchanger 34 that performs heat exchange, a circulation pump 35 that circulates the cooling water c in the heat exchanger 34, and a circulation pump 36 that circulates the exhaust heat hot water t in the heat exchanger 34 and the hot water storage unit 4 are provided. Yes.

  The hot water storage unit 4 includes a hot water storage tank 41 that stores exhaust heat from the fuel cell 32 as hot water, an auxiliary heater 42A that can heat the hot water consumption u derived from the hot water storage tank 41 and used mainly for hot water supply, Auxiliary heater 42B that can heat circulating hot water w that is circulated for heating and bathing, hot water consumption meter 49A that measures the flow rate of consumed hot water u, and circulation that measures the flow rate of circulating hot water w And a hot water flow meter 49B.

  The hot water storage tank 41 has a nozzle for introducing exhaust hot water t whose temperature has risen at the upper part and a nozzle for deriving the hot water consumption u toward a hot water supply load such as a hot water supply appliance, and a waste heat hot water having a lower temperature at the lower part. A nozzle for deriving t toward the heat exchanger 34 is arranged. A heating element 62 that generates heat by electricity is disposed in the upper part of the hot water storage tank 41.

  The auxiliary heater 42 </ b> A is disposed in the pipe 54 through which the consumed hot water u with a high temperature derived from the hot water tank 41 flows. The auxiliary heater 42A is configured to introduce the commercial gas G through the flow rate adjustment valve 48A, burn the introduced gas, and heat the consumed hot water u flowing in the pipe 54. The flow rate adjusting valve 48A is an electric two-way valve, and is configured to adjust the flow rate of the gas G introduced into the auxiliary heater 42A and to block the flow of the gas G. A signal cable is laid between the flow rate adjusting valve 48 </ b> A and the control device 9. The flow regulating valve 48A receives the signal from the control device 9 and opens and closes the valve, thereby controlling the introduction of the gas G to the auxiliary heater 42A and controlling the temperature of the consumed hot water u flowing in the pipe 54. It is configured to be able to.

  The auxiliary heater 42B is disposed in the pipe 55 through which the circulating hot water w flows. The auxiliary heater 42B is configured to introduce the commercial gas G through the flow rate adjustment valve 48B, burn the introduced gas, and heat the circulating hot water w flowing in the pipe 55. The flow rate adjustment valve 48B is an electric two-way valve, and is configured to adjust the flow rate of the gas G introduced into the auxiliary heater 42B and to block the flow of the gas G. A signal cable is laid between the flow rate adjusting valve 48B and the control device 9. The flow rate adjusting valve 48B receives a signal from the control device 9 and opens and closes the valve, thereby controlling the introduction of the gas G to the auxiliary heater 42B and controlling the temperature of the circulating hot water w flowing in the pipe 55. It is configured to be able to.

  A temperature detector 43 is arranged in the upstream pipe 54 of the auxiliary heater 42A, and a temperature detector 44 is arranged in the downstream pipe 54, respectively. A temperature detector 45 is arranged in the upstream pipe 55 of the auxiliary heater 42B, and a temperature detector 46 is arranged in the downstream pipe 55, respectively. A signal cable is laid between each temperature detector 43, 44, 45, 46 and the control device 9. The temperature detectors 43 and 44 are each configured to detect the temperature of the consumed hot water u flowing in the pipe 54 and to transmit the detected temperature of the consumed hot water u as a signal to the control device 9. The temperature detectors 45 and 46 are configured to detect the temperature of the circulating hot water w flowing in the pipe 55 and transmit the detected temperature of the circulating hot water w as a signal to the control device 9.

  A consumed hot water flow meter 49A and a circulating hot water flow meter 49B are respectively arranged in a pipe 54 on the downstream side of the temperature detector 44 and a pipe 55 on the downstream side of the temperature detector 46. The consumed hot water flow meter 49A is configured to measure the amount of consumed hot water u derived from the hot water tank 41, that is, the amount of hot water load. The circulating hot water flow meter 49B is configured to be able to measure the amount of circulating hot water w flowing through the heating appliance and the additional cooking pipe of the bath, that is, the amount of heating load and additional cooking load. A signal cable is laid between the consumption hot water flow meter 49A, the circulating hot water flow meter 49B and the control device 9, and the measurement result of the flow rate of the hot water measured by the consumption hot water flow meter 49A and the circulating hot water flow meter 49B. Can be transmitted to the control device 9 as signals as needed.

  The power consumption meter 39 introduces electricity generated by the fuel cell 32 and converted into alternating current by the inverter 33 and electricity E supplied from a commercial power source so as to supply electricity to power loads such as power of equipment and lamps. It is configured. The power consumption meter 39 is configured to measure how much power is loaded, how much power is generated by the fuel cell unit 3, and how much commercial power is supplied. Further, when the power generated by the fuel cell unit 3 is larger than the power load, the surplus power may flow backward to the commercial power source, but the power consumption meter 39 can measure the amount of power flowing backward. It is configured as follows. A signal cable is laid between the power consumption meter 39 and the control device 9, and the measurement result of the amount of generated current and the power load measured by the power consumption meter 39 is transmitted to the control device 9 as needed. It is configured to be able to.

  The control device 9 receives the gas G flow rate signal from the meter 2 or receives the gas G flow rate signal from the gas flow meter 37, and the flow rate and flow rate of the gas G introduced into the fuel cell unit 3. It is comprised so that the time until the flow of the gas G which passes the meter corresponding to can be grasped | ascertained can be grasped | ascertained. The control device 9 also receives the hot water flow meter 49A and the temperature detectors 43 and 44, and the circulating hot water flow meter 49B and the temperature detectors 45 and 46, respectively, to receive the warm water flow rate and temperature signals, and the auxiliary heater The flow rate of the gas G introduced into the hot water storage unit 4 can be grasped by grasping the flow rate and temperature difference of the hot water passing through 42A and 42B. That is, the amount of the gas G used in the auxiliary heaters 42A and 42B is theoretically (“hot water flow rate” × “temperature difference before and after the auxiliary heater”) / “specific to the gas G introduced into the auxiliary heater. Derived from “heat generation per unit flow rate”. Further, the control device 9 controls the meter 2 based on the signals received from the meter 2, the gas flow meter 37, the consumed hot water flow meter 49A, the circulating hot water flow meter 49B, and the temperature detectors 43, 44, 45, 46. An opening adjustment signal is transmitted to the flow rate adjusting valves 38, 48A and 48B as necessary, and the blower 88 is rotated as necessary so that the flow of the gas G is not interrupted by the operation of the safety device. A number adjustment signal is transmitted to control the generated current of the fuel cell unit 3 and the temperature of the consumed hot water u and the circulating hot water w derived from the hot water storage unit 4.

  The battery 61 is configured to be able to store surplus power when the power generated by the fuel cell unit 3 is greater than the power load. In addition, when the power generated by the fuel cell unit 3 is less than the power load or when the power load is sufficient for the amount of charge of the battery 61, the battery 61 is discharged and applied to a part or all of the power load. It is configured to be able to.

  The commercial gas G that has passed through the meter 2 is also supplied to a gas appliance 99 such as a stove outside the fuel cell system 1 other than the fuel cell unit 3 and the hot water storage unit 4 constituting the fuel cell system 1.

Next, the operation of the fuel cell system 1 will be described with reference to FIG.
In the reformer 31, the reformer s that is the reforming water and the commercial gas G that has passed through the meter 2 are introduced, and the fuel gas h rich in hydrogen by the steam reforming reaction between the reformer s and the commercial gas G. Is generated. The steam reforming reaction is an endothermic reaction, and the heat required for the reaction is obtained by burning the combustion gas in the combustion section 31a. The generated fuel gas h is sent to the fuel electrode 32a of the fuel cell 32.

  In the fuel cell 32, power is generated by an electrochemical reaction between the fuel gas h introduced into the fuel electrode 32a and the oxidant gas a introduced into the air electrode 32b by the blower 88 to generate water and heat. The fuel gas h and the oxidant gas a that have not been used for the reaction are discharged from the fuel cell 32 as an anode offgas p and a cathode offgas q, respectively. The anode off gas p is led to the combustion section 31a of the reformer 31 and burned as a combustion gas in order to obtain heat necessary for the steam reforming reaction. The current generated by the fuel cell 32 is a direct current, which is converted into an alternating current by the inverter 33 and transmitted to the power consumption meter 39. Water is generated at the air electrode 32b. When the generated water is water vapor, it is discharged after being mixed with the cathode off gas q, and when it is water droplets, it is discharged together with the cathode off gas q by the wind pressure of the oxidant gas a. The generated heat is cooled by the cooling water c flowing through the cooling water channel 32c. The cooling water c received by the cooling water flow path 32c is pumped to the heat exchanger 34 by the circulation pump 35, and is heat-exchanged with the exhaust heat water t.

  The waste heat hot water t is sampled from a portion at a lower temperature of the hot water storage tank 41 of the hot water storage unit 4 and is pumped to the heat exchanger 34 by the circulation pump 36. The exhaust heat water t that has received heat from the cooling water c by the heat exchanger 34 and has risen in temperature is returned to the upper part of the hot water storage tank 41. The hot water whose temperature has risen and returned to the hot water storage tank 41 is led from the upper part of the hot water storage tank 41 toward the hot water supply load such as a mixed water tap as consumed hot water u. The auxiliary heater 42A does not start if the temperature of the consumed hot water u derived from the hot water tank 41 is equal to or higher than the temperature required for the hot water supply load, but the temperature of the consumed hot water u derived from the hot water tank 41 requires the hot water load. If the temperature is equal to or lower than the temperature, the gas G whose flow rate is adjusted by the flow rate adjusting valve 48A is supplied to the auxiliary heater 42A, the auxiliary heater 42A is activated, and the consumed hot water u is heated to a predetermined temperature. Whether the auxiliary heater 42A is started or stopped is determined based on the temperature detected by the temperature detector 43, and the opening adjustment of the flow rate adjustment valve 48A is performed based on the temperature detected by the temperature detector 44. The flow rate of the consumed hot water u derived toward the hot water supply load is measured by the consumed hot water flow meter 49A, and the measured flow rate is transmitted to the control device 9 as needed.

  On the other hand, when a heating appliance (not shown) or a reheating bath is operated, the circulating hot water w starts to circulate. When an operation such as a heating appliance or a reheating bath is stopped, the circulation of the circulating hot water w stops. . While the circulating hot water w is circulating, the gas G whose flow rate is adjusted by the flow rate adjusting valve 48B is supplied to the auxiliary heater 42B, the auxiliary heater 42B is activated, and the circulating hot water w is set to a predetermined temperature. Heat. The opening adjustment of the flow rate adjusting valve 48B is performed based on the temperature detected by the temperature detector 46. The flow rate of the circulating hot water w flowing is measured by the consumption hot water flow meter 49B, and the measured flow rate is transmitted to the control device 9 as needed.

  The current transmitted from the fuel cell unit 3 to the power consumption meter 39 is transmitted toward a power load such as a light (not shown) or an electric device. If the amount of power generated by the fuel cell unit 3 is insufficient for the required power load, the shortage of power is supplied from the commercial power supply, and is supplied from the power generated by the fuel cell unit 3 and the commercial power supply. The received electric power E merges and is transmitted to the electric power load. The power transmitted to the power load is measured by the power consumption meter 39, and the measured power amount is transmitted to the control device 9 as needed as a signal.

  As described above, the gas G supplied from the commercial gas G and passing through the meter 2 is distributed to the fuel cell unit 3, the hot water storage unit 4, the gas appliance 99 outside the fuel cell system 1, and the like. If the power load is stable, the fuel cell unit 3 continues to operate so as to introduce a certain amount of gas and generate a certain amount of current. At this time, when the operation of the equipment using other gas is also stable, the fluctuation of the gas flow rate passing through the meter 2 is small, and the predetermined time corresponding to the gas flow rate elapses while the fluctuation of the gas flow rate is within the predetermined range. Then, the safety device of the meter 2 is activated and the supply of the gas G is shut off, and as a result, the fuel cell unit 3 cannot generate power. In addition, once the fuel cell unit 3 is stopped, it takes a considerable time from restarting to steady operation. When the fuel cell unit 3 does not generate electricity, it receives power from the commercial power supply to cover the power load. In such a case, combined with the time required for the fuel cell unit 3 to start up, The energy loss of the system 1 is increased.

  In order to avoid such an inconvenience, the fuel cell system 1 forcibly generates the generated current of the fuel cell before the safety device of the meter 2 operates when the fluctuation of the flow rate of the gas G is within a predetermined range. By changing the flow rate of the gas G passing through the meter 2, the flow of the gas G is prevented from being interrupted by the meter 2 without invalidating the protection function of the microcomputer meter. Driving is possible. Hereinafter, the operation in which the fuel cell unit 3 continuously operates will be described with reference to FIG. In addition, about the code | symbol of the structure used by the following description, FIG. 1 shall be referred suitably.

FIG. 3 is a flowchart for explaining the operation of continuously operating the fuel cell unit.
The control device 9 receives a gas G flow rate signal from the meter 2 and acquires flow rate information of the gas G flowing through the meter 2 (S301). When the flow rate of the gas G used outside the fuel cell system 1 is small or when the usage time is short, the gas flow meter 37, the consumed hot water flow meter 49A, the circulating hot water flow meter 49B, the temperature detectors 43, 44, The gas flow rate flowing through the meter 2 may be estimated based on information acquired from 45 and 46.

  When the flow rate information of the gas G flowing through the meter 2 is acquired, a predetermined time (see FIG. 2) corresponding to the gas flow rate is determined (S302). When the predetermined time is determined, it is determined whether or not the fluctuation of the gas G flow rate is within a predetermined range (S303). If it is not within the predetermined width, the measurement for a predetermined time is interrupted and the flow returns to the step (S301) for acquiring the flow rate information of the gas G passing through the meter 2 again.

  When the fluctuation of the gas flow rate is within the predetermined range, it is determined whether or not it remains for 5 minutes or more until a predetermined time corresponding to the gas flow rate elapses (S304). If more than 5 minutes remain, the process returns to the step of determining whether or not the fluctuation of the gas G flow rate is within the predetermined range (S303), and if the remaining 5 minutes until the predetermined time elapses, the process proceeds to the next step.

  When the fluctuation of the gas G flow rate is within the predetermined range and the remaining 5 minutes until the predetermined time elapses, the flow rate of the gas G introduced into the fuel cell unit 3 is changed in order to change the generated current of the fuel cell unit 3 (S305). . The electric power generated by the fuel cell unit 3 is supplied to the electric power load, but when the electric power generated by the fuel cell unit 3 exceeds the required electric power load, it is stored in the battery 61 and converted into heat by the heating element 62. Then, it is stored in the hot water in the hot water storage tank 41 and is reversely flowed to the commercial power source via the wattmeter 39. In this way, surplus power is effectively used without being discarded.

  After the generated current of the fuel cell unit 3 is changed, the flow rate of the gas G passing through the meter 2 is changed until it can be avoided that the safety device of the meter 2 is activated, that is, the gas G flow rate is changed over a predetermined width. It is determined whether or not it has been done (S306). If the gas G flow rate does not fluctuate more than the predetermined width, the process returns to the step (S305) of changing the generated current of the fuel cell unit 3, and if the gas G flow rate fluctuates more than the predetermined width, the process proceeds to the next step.

  If the gas G flow rate fluctuates by more than a predetermined width, the fuel cell unit 3 is returned to the steady operation state (S307). When the fuel cell unit 3 returns to the steady operation, the process returns to the step (S301) of acquiring the flow rate information of the gas G passing through the meter 2, and the series of operations is repeated until the operation of the fuel cell unit 3 is stopped.

  In the description of the operation of continuously operating the fuel cell unit 3, the flow rate information of the gas G flowing through the meter 2 is obtained by receiving a signal from the meter 2 (S301). When the information cannot be acquired, the embodiment of the present invention is modified so that the flow rate information of the gas G introduced into the fuel cell unit 3 is acquired by receiving a signal from the gas flow meter 37 in the fuel cell unit 3. be able to. It is highly possible that the fuel cell unit 3 operates continuously under an environment of constant power demand in the present age, and the stable continuous operation of the fuel cell unit 3 may cause the safety device of the meter 2 to operate. . At this time, even if the flow rate information of the gas G cannot be acquired from the meter 2, the gas G is introduced into the reforming device 31 of the fuel cell unit 3 based on the flow rate information of the gas G introduced into the fuel cell unit 3 acquired from the gas flow meter 37. If the flow rate of the gas G to be changed fluctuates by a predetermined width or more within a predetermined time, the flow rate of the gas G flowing through the meter 2 is generally considered to fluctuate by a predetermined width or more. Can be avoided.

  Similarly to the above, when the flow rate information of the gas G cannot be acquired from the meter 2, the sum of the flow rate of the gas G introduced into the fuel cell unit 3 and the flow rate of the gas G introduced into the hot water storage unit 4. Information on the flow rate of G may be acquired. The flow rate information of the gas G introduced into the fuel cell unit 3 can be acquired from the gas flow meter 37, and the flow rate information of the gas G introduced into the hot water storage unit 4 is obtained from the consumed hot water flow meter 49A and the circulating hot water flow meter 49B. It can acquire based on the flow rate information of the warm water which can be acquired, and the information of the temperature difference before and behind the auxiliary heaters 42A and 42B which can be acquired from the temperature detectors 43, 44, 45 and 46. In this way, information on the flow rate of the gas G obtained by adding the flow rate of the gas G introduced into the fuel cell unit 3 and the flow rate of the gas G introduced into the hot water storage unit 4 is acquired, and the total gas G within a predetermined time is obtained. When monitoring the fluctuation of the flow rate, even if the fuel cell unit 3 performs a stable continuous operation, if the gas G having a flow rate of a predetermined width or more is introduced into the auxiliary heaters 42A and 42B within a predetermined time, the meter 2 Therefore, the generated current of the fuel cell unit 3 can be prevented from fluctuating more than necessary.

  In addition, when the flow rate of the gas G, which is the sum of the flow rate of the gas G introduced into the fuel cell unit 3 and the flow rate of the gas G introduced into the hot water storage unit 4, is varied within a predetermined width within a predetermined time, The hot water storage unit 4 cannot acquire the flow rate information of the hot water from the hot water flow meter 49A and the circulating hot water flow meter 49B and the temperature difference between the auxiliary heaters 42A and 42B from the temperature detectors 43, 44, 45, and 46. Even if it is not possible to obtain information on the flow rate of the gas G introduced into the gas generator, if it is known in advance that the minimum gas consumption when the auxiliary heaters 42A and 42B are activated is greater than or equal to a predetermined width, within a predetermined time It is presumed that there has been a change in the gas flow rate of a predetermined width or more simply by obtaining a signal that the auxiliary heaters 42A and 42B have started and stopped, and the safety device of the meter 2 is activated. It can be determined that to avoid the, need a power generation current of the fuel cell unit 3 also in this case without change unnecessarily.

  In the above description, the reforming method has been described as the steam reforming method, but it may be a partial oxidation reforming method or an autothermal reforming method. When the partial oxidation reforming method or the autothermal reforming method is adopted, the combustion part 31a is not necessary, and the fuel cell unit 3 can be made compact.

  In the above description, the flow rate signal of the gas G passing through the meter 2 is transmitted from the meter 2 to the control device 9, but when the flow rate signal cannot be output from the meter 2, the downstream side of the meter 2 A flow meter may be installed in the pipe 52, and a flow signal of the gas G passing through the meter 2 may be transmitted from the flow meter to the control device 9.

  In the above description, the heating element 62 is installed in the hot water storage tank 41. However, the heating element 62 is installed in other parts that require heat, for example, the pipe 54 through which the hot water consumption u flows or the pipe 55 through which the circulating hot water w flows. Also good.

  As described above, the fuel cell system 1 according to the present embodiment can be operated continuously without blocking the flow of the gas G without invalidating the protection function of the meter 2.

1 is a block diagram illustrating a fuel cell system 1 according to an embodiment of the present invention. It is a figure which shows the table | surface of the relationship between the flow rate of the gas which flows through a meter, and the time required until the flow of gas interrupts | blocks. It is a flowchart explaining the operation | movement which drive | operates a fuel cell unit continuously.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fuel cell system 2 Meter 3 Fuel cell unit 4 Hot water storage unit 9 Control device 31 Reformer 32 Fuel cell 39 Power consumption meter 42A, 42B Auxiliary heater 49A Consumption hot water flow meter 49B Circulating hot water flow meter 61 Battery 62 Heating element G Commercial Gas h Fuel gas t Waste hot water u Consumption hot water w Circulating hot water

Claims (4)

Reformation that introduces a commercial gas that has passed through a meter having a function of interrupting the flow of the gas when a predetermined flow rate of gas flows for a certain period of time and reforms the commercial gas to produce a fuel gas rich in hydrogen A fuel cell unit having a device and a fuel cell that introduces the fuel gas and generates heat by an electrochemical reaction to generate heat;
Generated current generated by the fuel cell when fluctuations in the flow rate of the commercial gas passing through the meter are within a predetermined range until a predetermined time corresponding to the flow rate of the commercial gas passing through the meter elapses. And a control device that varies the flow rate of the commercial gas passing through the meter as the predetermined width is varied.
Fuel cell system. The fluctuation of the generated current is an increase of the generated current;
Including at least one of a battery for storing surplus power due to the increased generated current, a heating element for converting to heat, and a wattmeter that measures the reverse power to a commercial power source;
The fuel cell system according to claim 1. The fuel cell system according to claim 1 or claim 2;
When the flow rate of the commercial gas introduced into the reformer is within a predetermined range until a predetermined time corresponding to the flow rate of the commercial gas that has passed through the meter has elapsed instead of the control device. And a control device that fluctuates the flow rate of the commercial gas introduced into the reformer by the predetermined width or more as the generated current generated by the fuel cell is changed;
Fuel cell system. Heat generated in the fuel cell is stored using hot water as a medium, and a first auxiliary heater that introduces and burns commercial gas and heats the hot water, and hot water that circulates by introducing and combusting and introducing from the outside A hot water storage unit having at least one of a second auxiliary heater for heating
Instead of the control device, the flow rate of the commercial gas introduced into the reforming device, the first auxiliary heater, and the first time until a predetermined time corresponding to the flow rate of the commercial gas passing through the meter elapses. When the fluctuation of the total commercial gas flow rate with the commercial gas flow rate introduced into at least one of the two auxiliary heaters is within a predetermined range, the generation current generated by the fuel cell is changed. And a control device that varies the flow rate of the total commercial gas by more than the predetermined width;
The fuel cell system according to claim 3.

Images