JP2010086917A - Fuel cell system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell system capable of achieving power saving of maintenance while rapid stopping is carried out in the case abnormality occurs. <P>SOLUTION: The fuel cell system 10 has a reformer 20 to form a reformed gas g containing hydrogen, and a fuel cell 30 to introduce the reformed gas g and generate electric power, and includes an abnormality detecting means for detecting abnormality of the fuel cell system 10, and a control device 36 to stop the fuel cell system 10 when abnormality is detected, and to restart the fuel cell system 10 when the detected abnormality is one related to a prescribed minor fault. When abnormality is eliminated by restarting, maintenance can be eliminated. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a fuel cell system, and more particularly to a fuel cell system that can be quickly stopped when an abnormality occurs and can save labor for maintenance.

A fuel cell that uses hydrogen and oxygen to generate electric power through these electrochemical reactions has attracted attention as an environmentally friendly power generator. Fuel cells require hydrogen for power generation, but they are relatively difficult to obtain because the infrastructure for supplying hydrogen itself is not widespread. In many cases, a fuel cell system in which a reformer that generates reformed gas is provided in the fuel cell is constructed. When an abnormality occurs in the fuel cell system during operation of the fuel cell system, in general, inspection is performed in order to investigate the cause of the abnormality by stopping the operation of the fuel cell system. Under these circumstances, various abnormal conditions of the fuel gas production system are detected when an abnormality occurs in the fuel gas production system (equivalent to a reformer), which is intended to minimize maintenance work. And determining which stop processing pattern of the plurality of preset stop processing patterns the detected abnormal state belongs to, and performing appropriate stop processing according to the determined stop processing pattern Thus, there is an abnormal stopping method for a fuel gas production apparatus that can reduce maintenance work when an appropriate stopping process that can be started up next time is performed (see, for example, Patent Document 1).
JP 2005-251603 A (paragraphs 0039-0065, etc.)

  However, the above-described abnormal stop method requires a long time for determination because it determines which stop processing pattern the detected abnormal state belongs to from among a plurality of stop processing patterns. When the target for detecting an abnormality is only the fuel gas production device (reformer) as in the above-described abnormal stopping method, the number of stop processing patterns is not increased, and the time required for determination can be shortened. Even if the target for detecting an abnormality is extended to a fuel cell system including a reformer and a fuel cell, the contents of the detected abnormality are so diverse that a considerable amount of time is required for judgment. It was difficult to process.

  In view of the above-described problems, an object of the present invention is to provide a fuel cell system that can be quickly stopped when an abnormality occurs and can save labor for maintenance.

  In order to achieve the above object, a fuel cell system according to a first aspect of the present invention includes a reformer 20 that generates a reformed gas g containing hydrogen, a reformed gas, as shown in FIG. a fuel cell system 10 having a fuel cell 30 for generating power by introducing g; an abnormality detecting means for detecting an abnormality of the fuel cell system 10; and stopping the fuel cell system 10 when the abnormality is detected (For example, S3 in FIG. 4) and a control device 36 that restarts the fuel cell system 10 (for example, S8 in FIG. 4) when the detected abnormality is an abnormality relating to a predetermined minor failure.

  With this configuration, when an abnormality is detected, the fuel cell system is stopped regardless of whether the abnormality is an abnormality related to a minor failure, so that safety is improved. In addition, since the fuel cell system is restarted when the detected abnormality is related to a predetermined minor failure, maintenance can be omitted if the abnormality is resolved by the restart, and the abnormality is resolved. If not, it will stop again, improving safety.

  Moreover, when the fuel cell system according to the second aspect of the present invention is shown with reference to FIG. 1, for example, in the fuel cell system 10 according to the first aspect of the present invention, an abnormality related to a minor failure is It is determined so as to include at least one of an abnormality relating to a temperature distribution within a predetermined range in the vessel 20, an abnormality relating to the cooling water c that cools the fuel cell 30, and an abnormality relating to the value of the electric power generated by the fuel cell 30. ing.

  If comprised in this way, a maintenance can be abbreviate | omitted when abnormality is eliminated by restarting, detecting abnormality over the wide range of a fuel cell system.

  Further, the fuel cell system according to the third aspect of the present invention is the same as that shown in FIGS. 1 and 2, for example, in the fuel cell system 10 according to the first aspect or the second aspect of the present invention. A power conditioner 34 that converts the DC power generated at 30 into AC power and transmits it to the power load, comprising a power conditioner 34 that is linked to the commercial power supply 99; A misfire detecting means 125 (see FIG. 2) for detecting misfire of the burner 25b (see FIG. 2) in the reformer 20, and an overcurrent detector for detecting an overcurrent of the current applied to the power conditioner 34. 30E.

  If comprised in this way, a maintenance can be abbreviate | omitted when abnormality is eliminated by restarting, detecting abnormality over the wide range of a fuel cell system.

  The fuel cell system according to the fourth aspect of the present invention is, for example, referring to FIG. 1, and the fuel cell system according to any one of the first to third aspects of the present invention. 10, the control device 36 does not restart the fuel cell system 10 when the abnormality detection unit detects an abnormality relating to a minor failure having the same content in the first predetermined period. It is configured.

  If comprised in this way, it can estimate that the abnormality of the same content which cannot be eliminated by restarting has arisen, and can grasp | ascertain the content of abnormality reliably.

  Further, the fuel cell system according to the fifth aspect of the present invention, for example, referring to FIG. 1, shows the fuel cell system according to any one of the first to third aspects of the present invention. 10, the control device 36 is configured not to restart the fuel cell system 10 when the abnormality detecting means continuously detects an abnormality relating to a minor failure having the same content for a predetermined number of times.

  If comprised in this way, it can estimate that the abnormality of the same content which cannot be eliminated by restarting has arisen, and can grasp | ascertain the content of abnormality reliably.

  In addition, the fuel cell system according to the sixth aspect of the present invention is, for example, referring to FIG. 1, and the fuel cell system according to any one of the first to fifth aspects of the present invention described above. 10, the control device 36 is configured not to restart the fuel cell system 10 when the abnormality detection means detects an abnormality relating to a minor failure for a second predetermined number of times during a second predetermined period. Yes.

  If comprised in this way, it can estimate that the abnormality which cannot be eliminated even by restarting has arisen in the fuel cell system, and can check the content of the abnormality.

  In addition, the fuel cell system according to the seventh aspect of the present invention relates to any one of the fourth to sixth aspects of the present invention described above with reference to FIGS. 1 and 4, for example. In the fuel cell system 10, when the control device 36 detects an abnormality other than an abnormality related to a minor failure (No in S4 in FIG. 4) or when the control is performed so that the fuel cell system 10 is not restarted. It is configured to output a signal related to an alarm (S9 in FIG. 4).

  With this configuration, it is possible to promptly notify the user that an abnormality that cannot be resolved by restarting has occurred.

  According to the present invention, when an abnormality is detected, the fuel cell system is stopped regardless of whether the abnormality is an abnormality related to a minor failure, so that safety is improved. In addition, since the fuel cell system is restarted when the detected abnormality is related to a predetermined minor failure, maintenance can be omitted if the abnormality is resolved by the restart, and the abnormality is resolved. If not, it will stop again and safety will be improved.

  Embodiments of the present invention will be described below with reference to the drawings. In the drawings, the same or similar members are denoted by the same or similar reference numerals, and redundant description is omitted.

  First, the configuration of a fuel cell system 10 according to an embodiment of the present invention will be described with reference to FIG. FIG. 1 is a schematic system diagram of the fuel cell system 10. The fuel cell system 10 includes a reformer 20 that generates a reformed gas g rich in hydrogen, an air blower 29 as combustion air supply means, and a fuel cell 30 that generates electricity by an electrochemical reaction between hydrogen and oxygen. , A power conditioner 34 as a generated power adjusting means and a control device 36 for controlling the fuel cell system 10 are provided. The fuel cell system 10 also includes an electric heater 13 as a power consuming load that consumes surplus power when the electric power generated by the fuel cell 30 is surplus, the heat generated in the fuel cell 30, and the heat generated in the electric heater 13. It has a hot water storage tank 80 as a heat storage tank for storing.

  The reformer 20 is a device that introduces the raw material m1 and the reforming water s and generates a reformed gas g rich in hydrogen by a steam reforming reaction. The raw material m1 is typically a chain hydrocarbon (including natural gas) such as methane or ethane, or a mixture mainly composed of hydrocarbons such as methanol and petroleum products (kerosene, gasoline, naphtha, LPG, etc.) A hydrocarbon-based fuel obtained by vaporizing the gas and the like, which is suitable for combustion for heating, is used. The reforming water s may be steam. The reformed gas g rich in hydrogen is a gas containing hydrogen as a main component, and is a gas supplied to the fuel cell 30 containing hydrogen in an amount of 40% by volume or more, typically about 70 to 80% by volume. is there. The hydrogen concentration in the reformed gas g may be 80% by volume or more, that is, any concentration that can generate power by an electrochemical reaction with oxygen in the oxidant gas t when supplied to the fuel cell 30.

  Here, with reference to FIG. 2, the structure of the reformer 20 is demonstrated in detail. FIG. 2 is a schematic longitudinal sectional view of the reformer 20. The reformer 20 includes a reforming unit 21, a shift conversion unit 22, a selective oxidation unit 23, a reforming water introduction pipe 24, and a combustion unit 25. The reforming unit 21, the shift conversion unit 22, the selective oxidation unit 23, and the reforming water introduction pipe 24 are in communication with each other and are influenced by internal pressure fluctuations. It is comprised so that it can interrupt | block.

  The reforming unit 21 introduces the raw material m1 and the reforming water sv that has become steam, and reforms the raw material m1 into a semi-reformed gas r1 by a steam reforming reaction. The semi-reformed gas r1 typically contains about 70% by volume of hydrogen and about 10% by volume of carbon monoxide. The reforming unit 21 is filled with a reforming catalyst 21c and is configured to promote a steam reforming reaction. Typically, a nickel-based reforming catalyst or a ruthenium-based reforming catalyst is used as the reforming catalyst 21c. The reforming unit 21 is provided with a reforming unit temperature sensor 121 that detects the internal temperature. The reforming part temperature sensor 121 is typically disposed on the downstream side of the reforming catalyst 21c. Further, the reforming unit 21 is connected to the shift unit 22 on the downstream side of the reforming catalyst 21c so that the semi-reformed gas r1 generated in the reforming unit 21 is sent to the shift unit 22. In the following description, “connected” includes the case of being connected via a flow path or the like.

  The shift converter 22 introduces the semi-reformed gas r1 from the reformer 21, and causes the carbon monoxide contained in the semi-reformed gas r1 to undergo a shift reaction with the water contained in the semi-reformed gas r1, thereby producing carbon dioxide. And hydrogen are generated from the semi-reformed gas r1 to produce a modified gas r2 having a reduced carbon monoxide concentration. The modification reaction is an exothermic reaction. The shift unit 22 is filled with a shift catalyst 22c, and is configured to promote the shift reaction. Typically, the shift catalyst 22c is an iron-chromium shift catalyst, a copper-zinc shift catalyst, a platinum shift catalyst, or the like. The modified gas r2 generated in the shift unit 22 has a carbon monoxide concentration reduced to about 5000 to 10000 ppm. Further, the transformation unit 22 is provided with a transformation unit temperature sensor 122 that detects the internal temperature. The shift portion temperature sensor 122 is typically disposed on the downstream side of the shift catalyst 22c. The shift unit 22 is connected to the selective oxidation unit 23 on the downstream side of the shift catalyst 22c so that the shift gas r2 generated in the shift unit 22 is sent to the selective oxidation unit 23.

  The selective oxidation unit 23 introduces the transformation gas r2 from the transformation unit 22, introduces oxygen by introducing air a1 (hereinafter referred to as “selective oxidation air a1”) from the outside of the system, and remains in the transformation gas r2. By the selective oxidation reaction between the carbon monoxide thus introduced and the introduced oxygen, a reformed gas g having a further reduced carbon monoxide concentration is generated from the modified gas r2. The selective oxidation reaction is an exothermic reaction. The selective oxidation unit 23 is filled with a selective oxidation catalyst 23c. Typically, a platinum-based selective oxidation catalyst, a ruthenium-based selective oxidation catalyst, a platinum-ruthenium-based selective oxidation catalyst, or the like is used as the selective oxidation catalyst 23c. A selective oxidation air pipe 69 (not shown in FIG. 1) for introducing the selective oxidation air a1 is connected to the selective oxidation unit 23 upstream of the selective oxidation catalyst 23c. The selective oxidation air pipe 69 is provided with a selective oxidation air electromagnetic valve 27 for blocking the introduction of the selective oxidation air a1 to the selective oxidation unit 23 and a flow meter 169 for detecting the flow rate of the selective oxidation air a1 flowing in the pipe. ing. The selective oxidation unit 23 is provided with a selective oxidation unit temperature sensor 123 that detects the internal temperature. The selective oxidation unit temperature sensor 123 is typically disposed on the downstream side of the selective oxidation catalyst 23c. As described above, the reformed gas g generated in the selective oxidation unit 23 is a gas containing hydrogen of 40% or more, typically about 75%. The carbon monoxide concentration in the reformed gas g is about 10 ppm or less. A reformed gas pipe 51 for leading the reformed gas g is connected to the selective oxidation unit 23 on the downstream side of the selective oxidation catalyst 23c.

  The reforming water pipe 24 is disposed adjacent to the reforming unit 21 and adjacent to the transformation unit 22 and the selective oxidation unit 23. Adjacent to the shift unit 22 and the selective oxidation unit 23 is that the heat generated by the reaction in the shift unit 22 and the selective oxidation unit 23 is close to the extent that the reforming water s flowing in the reforming water pipe 24 receives heat. . The amount of heat received at this time is preferably such that the liquid reforming water s becomes gaseous reforming water (steam sv) before flowing into the reforming unit 21. Further, the reforming water pipe 24 is disposed so as to receive heat from the reforming unit 21. If the reforming water s flowing through the reforming water pipe 24 cannot receive sufficient heat to evaporate before flowing into the reforming unit 21, the combustion water 25 can be received in the combustion unit 25 or the combustion unit 25. The reforming water pipe 24 may be disposed in the vicinity.

  The combustion unit 25 typically has a burner 25b, introduces fuel used for combustion and combustion air a2, and burns the fuel used for combustion to generate reforming heat. The fuel used for the combustion is, for example, via a fuel for combustion m2 (typically the same as the raw material m1 supplied to the reforming unit 21 and the name is changed according to the application), and the anode off-gas line 52. One kind or two or more kinds of the introduced anode off gas p and the reformed gas g are used. The anode off gas p is a gas that is discharged from the fuel cell 30 (see FIG. 1) and contains hydrogen that has not been used for the electrochemical reaction in the fuel cell 30 (see FIG. 1). The combustion unit 25 is disposed close to the reforming unit 21 to such an extent that heat used for reforming can be given to the reforming unit 21, and preferably a space is formed in the center of the reforming unit 21. Thus, when it is formed in a bamboo ring shape and disposed in the central space, the reforming heat can be effectively transmitted to the reforming section 21. The combustion unit 25 is provided with a flame detector 125 that can detect “non-ignition” in which the burner 25 b does not ignite and “misfire” in which the flame during combustion disappears unintentionally. The flame detector 125 is typically composed of a frame rod and a temperature sensor as misfire detection means.

  The description will be continued with reference to FIG. A reformer 21 in the reformer 20 (see FIG. 2) is connected to a raw material pipe 55 for introducing the raw material m1. A raw material valve 65 is provided in the raw material pipe 55. A pressure gauge 155P for detecting the pressure in the pipe and a flow meter 155F for detecting the flow rate in the pipe are disposed in the raw material pipe 55 on the downstream side of the raw material valve 65. A reforming water pipe 96S for introducing the reforming water s is connected to the reforming water pipe 24 (see FIG. 2) in the reformer 20. The reforming water pipe 96S is provided with a reforming water valve 67 that blocks the flow of the reforming water s and a reforming water pump 26 that pumps the reforming water s. A pressure gauge 196 for detecting the pressure in the pipe is disposed in the reforming water pipe 96S downstream of the reforming water pump 26. The selective oxidation unit 23 (see FIG. 2) in the reformer 20 is connected to the reformed gas pipe 51 for deriving the reformed gas g as described above. An anode offgas pipe 52 capable of introducing the anode offgas p and the reformed gas g, a combustion fuel pipe 56 for introducing the combustion fuel m2, and combustion air a2 are introduced into the combustion section 25 in the reformer 20. A combustion air pipe 58 is connected. The combustion fuel pipe 56 is provided with a combustion fuel valve 66. A flow meter 156 for detecting the flow rate in the pipe is disposed in the combustion fuel pipe 56 downstream of the combustion fuel valve 66. The combustion air pipe 58 is provided with a flow meter 158 for detecting the flow rate in the pipe. Further, an exhaust gas pipe 59 for discharging the exhaust gas e after being burned by the burner 25b (see FIG. 2) is connected to the combustion unit 25.

  The raw material pipe 55 and the combustion fuel pipe 56 are branched from one fuel pipe 57 through which the fuel m before being divided into the raw material m1 and the combustion fuel m2 flows. A fuel blower 28 that sends gaseous fuel m is disposed in the fuel pipe 57. The fuel blower 28 is typically configured such that the rotational speed (rpm) can be adjusted by an inverter, whereby the flow rate of the fuel m can be increased or decreased. When the fuel m is liquid, a fuel pump is provided in place of the fuel blower 28. In the present embodiment, the fuel blower 28 will be described. The fuel pipe 57 includes a meter 15 that can detect a change in the flow rate of the fuel m introduced into the reformer 20 and a pressure gauge 157 that detects the pressure of the fuel m flowing in the fuel pipe 57. It is arranged.

  The fuel cell 30 is typically a polymer electrolyte fuel cell. The fuel cell 30 includes an anode 31 that introduces a reformed gas g, a cathode 32 that introduces an oxidant gas t, and a cooling unit 33 that removes heat generated by an electrochemical reaction. The oxidant gas t introduced to the cathode 32 is typically air. Although the fuel cell 30 is shown in a simplified manner in the figure, in practice, a single cell is formed by sandwiching a solid polymer membrane between an anode 31 and a cathode 32, and this cell is interposed via a cooling unit 33. A plurality of layers are laminated. In the fuel cell 30, hydrogen in the reformed gas g supplied to the anode 31 is decomposed into hydrogen ions and electrons, and the hydrogen ions pass through the solid polymer film and move to the cathode 32, and the electrons move to the anode 31. It moves to the cathode 32 through a conducting wire connecting to the cathode 32, reacts with oxygen in the oxidant gas t supplied to the cathode 32 to generate water, and generates heat during this reaction. In this reaction, the direct current can be taken out by passing electrons through the conducting wire. The fuel cell 30 has a plurality of cells housed in a housing (not shown). A gas detector 138 for detecting leakage of combustible gas (reformed gas g, anode off gas p) and a thermometer 139 for detecting the temperature in the housing are provided inside the housing (not shown). Yes. The fuel cell 30 is electrically connected to the power conditioner 34 via the output cable 41. The fuel cell 30 is connected to an output meter 30E that detects an output voltage and an output current of the electric power generated by the electrochemical reaction. The output meter 30E also functions as an overcurrent detector that detects overcurrent.

  The fuel cell 30 is connected to a commercial power source 99 via an output cable 41 and a commercial power cable 49. A power load cable 48 connected to the power load 98 is connected to a connection portion between the output cable 41 and the commercial power cable 49. That is, the fuel cell 30, the commercial power source 99, and the power load 98 are electrically connected. The power load 98 is typically an electric device such as a home appliance or a production machine. A power conditioner 34 is disposed on the output cable 41. A heater cable 42 connected to the electric heater 13 is connected to the output cable 41 closer to the commercial power cable 49 than the power conditioner 34. A switch 43 is disposed on the heater cable 42. The switch 43 is typically a solid state relay. The commercial power cable 49 is provided with a power meter 45 that measures the power supplied from the commercial power source 99.

  The power conditioner 34 has an inverter that converts DC power generated by the fuel cell 30 into AC power. Further, the power conditioner 34 arbitrarily determines the magnitude of the generated current in the fuel cell 30 between the minimum power generation amount (for example, 30% of the rated output) and the rated output. It is configured to be able to. That is, the power conditioner 34 can adjust the power generated by the fuel cell 30. In the fuel cell 30, hydrogen and oxygen sufficient to generate the current set by the power conditioner 34 react. The power conditioner 34 may include a commercial power supply abnormality detection unit that detects a malfunction of the commercial power supply 99 linked to the fuel cell 30.

  The anode 31 and the reforming unit 21 (see FIG. 2) are connected via a reformed gas pipe 51. The reformed gas pipe 51 is provided with a reformed gas valve 61. Further, the anode 31 and the combustion unit 25 are connected via an anode off-gas pipe 52, and an anode off-gas p containing hydrogen that has not been used for an electrochemical reaction in the fuel cell 30 can be introduced into the combustion unit 25. It can be done. An anode off gas valve 62 is disposed in the anode off gas pipe 52. A reformed gas pipe 51 upstream of the reformed gas valve 61 and an anode offgas pipe 52 downstream of the anode offgas valve 62 are connected by a bypass pipe 53. A bypass valve 63 is provided in the bypass pipe 53. Connected to the cathode 32 are an oxidant gas pipe 54 for introducing an oxidant gas t and a cathode offgas pipe 54Q for discharging a cathode offgas q containing oxygen that has not been used in the electrochemical reaction in the fuel cell 30. ing. The oxidant gas pipe 54 is one of the pipes branched from the air pipe 54A, and the other one branched from the air pipe 54A is the combustion air pipe 58. An air blower 29 that sends an oxidant gas t to the cathode 32 and sends combustion air a2 to the combustion section 25 is disposed in the air pipe 54A. The air blower 29 is typically configured such that the rotational speed (rpm) can be adjusted by an inverter, whereby the flow rates of the combustion air a2 and the oxidizing gas t can be increased or decreased. The oxidant gas pipe 54 is provided with an oxidant gas cutoff valve 64 capable of blocking the flow of the oxidant gas t and a flow meter 154 for detecting the flow rate in the pipe. The oxidant gas pipe 54 is typically provided with a humidifier (not shown) that humidifies the oxidant gas t.

  A reformed gas gas-liquid separator 91 that separates excess water from the reformed gas g is disposed in the reformed gas pipe 51 on the downstream side of the reformed gas valve 61. An anode off gas gas / liquid separator 92 that separates moisture in the anode off gas p is disposed in the anode off gas pipe 52 upstream of the anode off gas valve 62. The cathode offgas pipe 54Q is provided with a cathode offgas gas-liquid separator 94 that separates moisture in the cathode offgas q. An exhaust gas gas-liquid separator 93 that separates moisture in the exhaust gas e is disposed in the exhaust gas pipe 59 connected to the combustion unit 25 of the reformer 20. The recovered water separated by each gas-liquid separator 91, 92, 93, 94 is collected in a recovered water tank 96. The recovered water separated by the reformed gas / liquid separator 91 is guided to a recovered water tank 96 through a recovered water pipe 91A. Similarly, the recovered water separated by the anode off-gas gas-liquid separator 92 is separated by the cathode off-gas gas-liquid separator 94 by the collected water pipe 92A and the collected water separated by the exhaust gas-liquid separator 93 by the collected water pipe 93A. The recovered water is led to the recovered water tank 96 through the recovered water pipe 94A. The recovered water tank 96 is provided with a recovered water level meter 97 that detects the water level in the recovered water tank 96. Further, a reforming water pipe 96S is connected to the recovered water tank 96 so that the recovered water collected in the recovered water tank 96 can be supplied to the reformer 20 as reforming water s. Yes. Instead of providing the exhaust gas gas / liquid separator 93 and the cathode off gas gas / liquid separator 94, one cathode gas gas / liquid separator is provided in a portion where the cathode off gas pipe 54Q and the exhaust gas pipe 59 are connected to form one pipe. A vessel may be provided to separate water in the mixed exhaust gas in which the exhaust gas e and the cathode offgas q are mixed.

  A cooling water pipe 75 is connected to the cooling water inlet of the cooling unit 33 of the fuel cell 30, and a cooling water pipe 74 is connected to the cooling water outlet. Through the cooling water pipes 74 and 75, the cooling water c derived from the fuel cell 30 passes through the heat exchanger 70, and the cooling water c that has passed through the heat exchanger 70 and has been cooled down is introduced into the fuel cell 30. A circulation channel is formed at the bottom. A cooling water pump 73 that circulates the cooling water c flowing inside is disposed in the cooling water pipe 75. The cooling water pump 73 is typically configured such that the rotation speed (rpm) is adjusted by an inverter, and the flow rate of the cooling water c can be adjusted according to the amount of heat generated by the fuel cell 30. The inverter of the cooling water pump 73 and the control device 36 are connected by a signal cable. A pressure gauge 173D is disposed on the discharge side of the cooling water pump 73, and a pressure gauge 173S is disposed on the suction side. The flow rate of the cooling water c is determined by the difference in pressure detected by both pressure gauges 173D and 173S. It is comprised so that it can detect. The cooling water pipe 75 is provided with a thermometer 175 that detects the temperature of the cooling water c introduced into the cooling unit 33. On the other hand, the cooling water pipe 74 is provided with a thermometer 174 that detects the temperature of the cooling water c derived from the cooling unit 33.

  The electric heater 13 is disposed in the cooling water pipe 74. The electric heater 13 converts surplus electric power that is not consumed by the electric power load 98 such as an electric lamp or an electric device from the electric power generated by the fuel cell 30 into heat, and transmits the converted heat to the cooling water c flowing through the cooling water pipe 74. It is configured as follows. The electric heater 13 is typically a cable-type electric heater in which a heat generating portion is covered with an insulating material, and is wound around the outer periphery of the cooling water pipe 74 and fixed with tape. Further, the electric heater 13 may be configured to introduce the cooling water c into the casing that houses the heat generating portion, and the temperature of the cooling water c is increased by the heat generating portion and the cooling water c coming into contact with each other. When the electric heater 13 generates heat, the cooling water c whose temperature has increased in the cooling unit 33 is further increased in temperature by the electric heater 13 and flows into the heat exchanger 70. The electric heater 13 is provided with a thermometer 113 that detects the temperature of the electric heater 13.

  The heat exchanger 70 is a device that performs heat exchange between the cooling water c and the heat storage water h, and a plate-type heat exchanger is typically used. The heat exchanger 70 receives heat from the fuel cell 30 and exchanges heat between the cooling water c whose temperature has risen and the heat storage water h whose temperature is lower than that of the cooling water c by a counter flow, and the exhaust heat of the fuel cell 30 is cooled with cooling water. It is comprised so that it may transmit to the thermal storage water h from c. The heat exchanger 70 receives the cooling water c that has received heat from the fuel cell 30 and introduces the cooling water c that has been cooled by heat exchange between the cooling water introduction port that introduces the cooling water c and the heat storage water h. And a heat storage water inlet for introducing the heat storage water h having a low temperature and a heat storage water outlet for deriving the heat storage water h having a temperature increased by heat exchange with the cooling water c. A cooling water pipe 74 is connected to the cooling water inlet of the heat exchanger 30, and a cooling water pipe 75 is connected to the cooling water outlet.

  A heat storage water pipe 84 is connected to the heat storage water outlet of the heat exchanger 70, and a heat storage water pipe 85 is connected to the heat storage water inlet. The heat storage water pipe 84 is connected to the upper part of the hot water storage tank 80 so that the heat storage water h led out from the heat exchanger 70 flows into the upper part of the hot water storage tank 80, and is preferably connected to the top. The heat storage water pipe 85 is connected to the lower part of the hot water tank 80 so that the heat storage water h introduced into the heat exchanger 70 is sampled from the lower part of the hot water tank 80, and is preferably connected to the bottom part. The heat storage water tubes 84 and 85 are connected to the heat exchanger 70 and the hot water storage tank 80 to form a circulation channel. A heat storage water pump 83 that circulates the heat storage water h flowing inside is disposed in the heat storage water pipe 85. The heat storage water pump 83 is typically configured to adjust the rotation speed (rpm) by an inverter and to adjust the flow rate of the heat storage water h according to the amount of heat exchanged in the heat exchanger 70. The inverter of the heat storage water pump 83 and the control device 36 are connected by a signal cable. The heat storage water pipe 85 is provided with a flow meter 183 that detects the flow rate of the heat storage water h flowing inside.

  The hot water storage tank 80 has a heat storage water introduction port for introducing the heat storage water h having a high temperature at the top and a heat storage water outlet for deriving the heat storage water h having a low temperature at the bottom. As described above, the heat storage water pipe 84 is connected to the heat storage water inlet of the hot water tank 80, and the heat storage water pipe 85 is connected to the heat storage water outlet. The heat storage water h that has received the exhaust heat of the fuel cell 30 by the heat exchanger 70 flows into the hot water storage tank 80 through the heat storage water pipe 84, and the exhaust heat of the fuel cell 30 is stored in the hot water storage tank 80. Yes. The heat storage water h that flows in and is stored in the hot water storage tank 80 is formed with a temperature stratification in which the upper temperature is high and the lower temperature is low. Further, a hot load hot water outlet for deriving hot water w1 is provided in the upper part of the hot water tank 80, and the hot water w1 is derived from the thermal load hot water outlet for use in heat demand such as hot water supply and heating. The In addition, a replenishment water introduction port is provided below the hot water storage tank 80 to compensate for the reduced amount of water used for heat demand. The makeup water w2 is introduced from the makeup water inlet.

  A bypass pipe 86 is connected to the heat storage water pipe 84, and the other end of the bypass pipe 86 is connected to the heat storage water pipe 85 upstream of the heat storage water pump 83. The bypass pipe 86 is a pipe that guides the heat storage water h flowing through the heat storage water pipe 84 to the heat storage water pipe 85 without flowing into the hot water storage tank 80. The bypass pipe 86 is provided with a radiator 81 as a cooling device that can lower the temperature of the heat storage water h. When the temperature of the heat storage water h led out from the hot water storage tank 80 is so high that the radiator 81 cannot take heat from the cooling water c until the temperature of the cooling water c necessary for cooling the fuel cell 30 is reached. The temperature of the heat storage water h introduced into the heat exchanger 70 can be cooled to a temperature at which heat can be taken from the cooling water c. The radiator 81 includes fins as cooling plates, and is configured so that the temperature of the heat storage water h can be lowered by introducing the heat storage water h into the fin and exchanging heat with air. Further, the radiator 81 includes an air supply fan (not shown) that forcibly sends air to the fins in order to supply more air to the fins and increase the amount of heat exchanged.

  A three-way valve 82 for switching the flow direction of the heat storage water h is disposed at a branch portion between the heat storage water pipe 84 and the bypass pipe 86. Further, the installation position of the three-way valve 82 is not limited to the upstream side of the hot water storage tank 80 and the radiator 81, and may be the downstream side of the hot water storage tank 80 and the radiator 81. Further, by using two two-way valves instead of the three-way valve 82, the flow direction of the heat storage water h is switched, or the flow rate of the heat storage water h flowing into the hot water storage tank 80 and the flow rate of the heat storage water h flowing into the radiator 81. You may comprise so that distribution with can be adjusted.

  The control device 36 controls the operation of the fuel cell system 10. The control device 36 transmits signals to the fuel blower 28 and the air blower 29 to control the start and stop, and controls the flow rate of the fluid discharged from the fuel blower 28 and the air blower 29. Further, the control device 36 controls the start and stop by transmitting a signal to the cooling water pump 73 and the heat storage water pump 83 and also controls the flow rate of the fluid discharged from the cooling water pump 73 and the heat storage water pump 83. Note that transmitting a signal to each of the blowers 28 and 29 and each of the pumps 73 and 83 includes transmitting a signal to a power panel (not shown) that transmits power to them. Further, the control device 36 transmits a signal to the power conditioner 34 to set the generated current in the fuel cell 30. Further, the control device 36 is connected to each of the valves 61 to 67 by a signal cable, and is configured to transmit an open / close signal to open / close the valve. Moreover, the control apparatus 36 is connected with the three-way valve 82 by a signal cable, and is configured to transmit a signal and switch the flow path of the heat storage water h. In addition, the control device 36 transmits a signal to the switch 43 to control whether the electric heater 13 is energized. The control device 36 is connected to the meter 15 by a signal cable, and is configured to receive a signal and detect the flow rate of the fuel m.

  In addition, the control device 36 transmits signals to the reforming unit temperature sensor 121 (see FIG. 2), the shift unit temperature sensor 122 (see FIG. 2), and the selective oxidation unit temperature sensor 123 (see FIG. 2) in the reformer 20, respectively. It is connected by a cable and is configured to receive a temperature signal. Further, the control device 36 is connected to the flame detector 125 (see FIG. 2) of the combustion unit 25 by a signal cable, and the state of the burner 25b detected by the flame detector 125 (see FIG. 2) is detected by a temperature signal or a flame. It is comprised so that it can receive as a current signal of a rod. The control device 36 is connected to the wattmeter 45 through a signal cable, and is configured to receive a power value signal. The control device 36 is connected to the thermometers 113, 139, 174, and 175 through signal cables, respectively, and is configured to receive a temperature signal. The control device 36 is connected to the pressure gauges 155P, 157, 173D, 173S, and 196 through signal cables, respectively, and is configured to receive a pressure signal. The control device 36 is connected to the flow meters 154, 155F, 156, 158, 169 (see FIG. 2) and 183 via signal cables, and is configured to receive a flow signal. The control device 36 is connected to the gas detector 138 with a signal cable, and is configured to receive the presence of combustible gas detected by the gas detector 138 as a signal.

  Further, the control device 36 determines the presence / absence of an abnormality from the received various signals, and if it is determined that there is an abnormality, a determination unit 36j that determines whether the abnormality corresponds to an abnormality relating to a predetermined minor failure. Have. The determination unit 36j stores the content of abnormality related to a light failure that is determined in advance. The abnormality relating to the predetermined minor failure will be described later.

  The operation of the fuel cell system 10 will be described with reference to FIGS. 1 and 2. In order to start the operation of the stopped fuel cell system 10, the fuel blower 28 is activated to supply the combustion fuel m <b> 2 to the combustion unit 25, and the air blower 29 is activated to combust the air a <b> 2 to the combustion unit 25. Supply. At this time, the combustion fuel valve 66 is open, and the other valves 61 to 65, 67 are closed. When the combustion fuel m2 burns in the combustion unit 25 and reforming heat is generated and the reforming unit 21 is heated, the material valve 65 is opened and the material m1 is introduced into the reforming unit 21. The temperature of the reforming unit 21 is detected by the reforming unit temperature sensor 121. At this time, the reforming water valve 67 is opened and the reforming water pump 26 is activated, and the reforming water s is also introduced into the reforming section 21, and the reforming heat is obtained from the combustion section 25 to obtain the raw material m 1. A steam reforming reaction occurs, and reformed gas g is generated. In the reformer 20, the reformed gas g is generated as described above, but since the composition of the reformed gas g is not stable at the beginning of operation, the reformed gas valve 61 and the anode off-gas valve 62 are closed. Then, the bypass valve 63 is opened, and the reformed gas g whose composition is not stable is led to the combustion section 25 without being supplied to the fuel cell 30 and burned. At this time, the reformed gas g having an unstable composition introduced into the combustion section 25 is mainly combusted, and the insufficient amount of combustion fuel m2 is introduced into the combustion section 25 by adjusting the opening of the combustion fuel valve 66. When the reformed gas g whose composition is not stable is sufficient, the combustion fuel valve 66 is closed.

  When the composition of the reformed gas g generated in the reformer 20 is stabilized and the carbon monoxide concentration in the reformed gas g is reduced to a predetermined value, the controller 36 controls the reformed gas valve 61 and the anode. The off gas valve 62 is opened and the bypass valve 63 is closed so that the reformed gas g is introduced into the fuel cell 30. As a result, the reformed gas g is introduced into the anode 31 of the fuel cell 30. At this time, excess water in the reformed gas g is separated by passing through the reformed gas gas-liquid separator 91 before the reformed gas g is introduced into the anode 31, and the recovered water tank 96 is recovered as recovered water. To be collected. The recovered water collected in the recovered water tank 96 is supplied to the reformer 20 by the reforming water pump 26 so as to be used as the reforming water s. When the recovered water in the recovered water tank 96 is lowered to a predetermined low water level, makeup water (for example, city water) is supplied through a makeup water pipe (not shown). On the other hand, the control device 36 opens the oxidant gas cutoff valve 64, whereby the oxidant gas t is introduced into the cathode 32 of the fuel cell 30. Typically, the reformer gas g is supplied to the anode 31 so that the utilization rate of hydrogen is about 70 to 80%, preferably about 75%. (The raw material m1 is introduced into the reforming unit 21 accordingly). In addition, the rotation speed of the air blower 29 and a flow rate adjusting valve (not shown) are supplied so that an amount of oxidant gas t with an oxygen utilization rate of about 45 to 60%, preferably about 50%, is supplied to the cathode 32. Adjusted.

In the fuel cell 30, an electrochemical reaction is performed between hydrogen in the reformed gas g introduced into the anode 31 and oxygen in the oxidant gas t introduced into the cathode 32. As for the electrochemical reaction, the reaction represented by the following formula (1) is performed on the anode 31 side, and the reaction represented by the following formula (2) is performed on the cathode 32 side.
2H ₂ → 4H ⁺ + 4e ⁻ (1)
O ₂ + 4H ⁺ + 4e ⁻ → 2H ₂ O (2)
Electricity is generated by this electrochemical reaction, heat is generated, and moisture is generated. In further explanation, electric power can be obtained when electrons on the anode 31 side move to the cathode 32 side through the external electric circuit. Hydrogen ions on the anode 31 side pass through the solid polymer film and move to the cathode 32 side, and combine with oxygen to generate moisture. This electrochemical reaction is an exothermic reaction.

  Since the power obtained by the fuel cell 30 is DC power, it is converted into AC power by the power conditioner 34 and transmitted to the power load 98 and to the blowers 28 and 29 and the pumps 73 and 83. The electric power generated by the fuel cell 30 is set to a predetermined value (for example, 90% of the total power consumption) with respect to the total power consumption of the power load 98, the blowers 28 and 29, and the pumps 73 and 83. It is set by the inverter 34. The amounts of the reformed gas g and the oxidant gas t supplied to the fuel cell 30 are adjusted by the control device 36 so that the supply amount is appropriate for the set value. The insufficient power is supplied with AC power from the commercial power source 99.

  During the operation of the fuel cell 30, the anode off gas p is discharged from the anode 31. The discharged anode off gas p is guided to the combustion unit 25 of the reformer 20 through the anode off gas pipe 52 and burned. The anode off gas p is separated from the moisture by the anode off gas gas-liquid separator 92 in the middle of being led to the combustion unit 25. The water separated by the anode off-gas gas-liquid separator 92 is collected in the recovered water tank 96 as recovered water. The anode off gas p guided to the combustion unit 25 can generate reforming heat used for reforming in the reforming unit 21 by burning. When the reforming heat generated by the combustion of the anode off gas p introduced into the combustion unit 25 is insufficient, the combustion fuel m2 is introduced into the combustion unit 25 by adjusting the opening of the combustion fuel valve 66. The exhaust gas e generated by the combustion in the combustion unit 25 is discharged out of the system through the exhaust gas pipe 59. Before the exhaust gas e is discharged out of the system, moisture is separated by the exhaust gas-liquid separator 93, and the separated moisture is collected in the recovered water tank 96 as recovered water. On the other hand, the cathode offgas q is discharged from the cathode 32 and discharged out of the system via the cathode offgas pipe 54Q. The cathode offgas q is separated from the water by the cathode offgas gas-liquid separator 94 before being discharged out of the system, and the separated water is collected in the recovered water tank 96 as recovered water.

  As described above, since the electrochemical reaction in the fuel cell 30 is an exothermic reaction, the heat generated to continue the operation of the fuel cell 30 is removed by the cooling water c. When the reformed gas g and the oxidant gas t are introduced into the fuel cell 30 and power generation is performed, the control device 36 activates the cooling water pump 73 and the heat storage water pump 83 to start the cooling water c and the heat storage water h. Circulate. The temperature of the cooling water c introduced into the cooling unit 33 rises due to the heat generated by the electrochemical reaction in the fuel cell 30. The fuel cell 30 is maintained at a temperature suitable for operation (about 60 ° C. to 80 ° C.) after the heat generation is removed by the cooling water c. The cooling water c derived from the cooling unit 33 flows toward the heat exchanger 70 and is introduced into the heat exchanger 70. When the electric heater 13 is operating, the temperature further rises from the temperature derived from the cooling unit 33 and is introduced into the heat exchanger 70. The cooling water c introduced into the heat exchanger 70 undergoes heat exchange with the heat storage water h, the temperature drops, and is again introduced into the cooling unit 33. Thereafter, the above-described cycle is continued.

  On the other hand, the heat storage water h introduced into the heat exchanger 70 exchanges heat with the cooling water c, and the temperature rises. The heat storage water h whose temperature has risen is led out from the heat exchanger 70 and flows toward the hot water storage tank 80, and typically flows into the hot water storage tank 80 from above. The heat storage water h flowing into the hot water storage tank 80 is at a temperature that can be used for heat demand (not shown) such as hot water supply or heating. In the hot water storage tank 80, due to the density difference of the heat storage water h, water having a high temperature is stored in the upper part and water having a low temperature is stored in the lower part, thereby forming a temperature stratification. For this reason, from the viewpoint of not destroying the formed temperature stratification as much as possible, it is preferable that the dynamic pressure of the heat storage water h flowing into the hot water storage tank 80 is low (the flow velocity is small). However, if the dynamic pressure is too low, the diameter of the heat storage water pipe 84 becomes thick and the installation space and installation cost increase, so the dynamic pressure is lowered within an allowable range.

  As for the heat storage water h stored in the hot water storage tank 80, water having a high upper temperature is supplied to the heat demand (not shown) as the hot water w1, and the heat of the hot water w1 is consumed. Thus, by effectively using the heat generated in the fuel cell 30, the efficiency of the fuel cell system 10 is improved. The hot water w <b> 1 supplied to the heat demand (not shown) is returned to the lower part of the hot water tank 80 after the heat is used and the temperature is lowered. Or when not only the heat of the warm water w1 but the warm water w1 itself is consumed, the reduced amount of water is introduced into the lower portion of the hot water tank 80 from the outside (for example, city water) as the makeup water w2. Thereby, water having a low temperature is stored in the lower part of the hot water tank 80. The heat storage water h at the lower temperature of the hot water storage tank 80 flows through the heat storage water pipe 85 and is introduced into the heat exchanger 70. The heat storage water h introduced into the heat exchanger 70 exchanges heat with the cooling water c, and the temperature rises, and is derived from the heat exchanger 70.

  There is no heat consumption in the heat demand (not shown), and the temperature of the water stored in the lower part of the hot water tank 80 (the water led out toward the heat exchanger 70) is required to cool the fuel cell 30. When the cooling water c reaches a temperature (temperature at which the operation of the fuel cell 30 can be continued) cannot be cooled (so-called full storage), the heat storage water h in the hot water storage tank 80 is directly supplied to the heat exchanger 70. If it is introduced, the operation of the fuel cell 30 cannot be continued. In such a case, the control device 36 switches the three-way valve 82 to guide the heat storage water h derived from the heat exchanger 70 to the radiator 81 instead of the hot water tank 80. The heat storage water h introduced into the radiator 81 from the heat storage water pipe 84 dissipates heat to the atmosphere, the temperature decreases, flows into the heat storage water pipe 85, and is introduced into the heat exchanger 70. By dissipating heat that cannot be consumed by the radiator 81, the operation of the fuel cell 30 can be continued.

  When power generation in the fuel cell 30 is stopped due to a decrease in power demand at the power load 98, the supply of the reformed gas g and the oxidant gas t to the fuel cell 30 is stopped. As the supply of the reformed gas g to the fuel cell 30 is stopped, the reforming is performed by stopping the supply of the raw material m1 and the reforming water s to the reformer 20 in order to stop the generation of the reformed gas g. The operation of the vessel 20 is stopped. While the reformer 20 is stopped, the reforming catalyst 21c, the shift catalyst 22c, and the selective oxidation catalyst 23c are deteriorated due to oxidation when air is mixed therein. In order to prevent this, the reformed gas g or the gas m1 is supplied to the reforming unit. 21, the transformation unit 22, and the selective oxidation unit 23. While the reformed gas g or the raw material m1 is being sealed, at least the reformed gas valve 61, the bypass on-off valve 63, and the raw material valve 65 are closed.

  As described above, the fuel cell system 10 is composed of a large number of members, and various abnormality detection means are provided so that an abnormality can be detected quickly when an abnormality occurs. The abnormality detection unit functions by the cooperative operation of the determination unit 36j of the control device 36 and each member described below.

  FIG. 3 is a diagram for explaining the relationship between the content of the abnormality and the members constituting the abnormality detection means that detects the abnormality in cooperation with the determination unit 36j. As can be understood with reference to FIG. 3, the flame detector 125 is used for detecting non-ignition or misfire of the burner 25 b of the reformer 20 (numbers 1 and 21). The reforming unit temperature sensor 121 is used for detecting an abnormality related to the temperature of the reforming unit 21 (numbers 2 and 22). The metamorphic part temperature sensor 122 is used for detecting an abnormality related to the temperature of the metamorphic part 22 (No. 3). The selective oxidation unit temperature sensor 123 is used to detect an abnormality related to the temperature of the selective oxidation unit 23 (No. 4). The flow meter 155F is used for detecting an abnormality related to the amount of the raw material m1 introduced (No. 5). The pressure gauge 196 is used to detect an abnormality related to the amount of reforming water s introduced (No. 6). The thermometer 113 is used for detecting an abnormality related to the temperature of the electric heater 13 (No. 7). The recovered water level gauge 97 is used to detect an abnormality related to the level of recovered water in the recovered water tank 96 (numbers 8 and 24). The flow meter 183 is used for detecting an abnormality related to the flow rate of the heat storage water h (No. 9). The flow meter 169 is used for detecting an abnormality related to the flow rate of the selectively oxidized air a1 (No. 10). The thermometers 174 and 175 are used for detecting an abnormality related to the temperature of the cooling water c (numbers 11 and 12). The pressure gauges 173D and 173S are used for detecting an abnormality related to the flow rate of the cooling water c (No. 13).

  The pressure gauge 155P is used to detect an abnormality related to the supply pressure of the reformed gas g and an abnormality related to the sealing pressure of the raw material m1 or the reformed gas g into the reformer 20 (numbers 14 and 23). The output meter 30E is used to detect an abnormality related to the output voltage and output current of the fuel cell 30 (numbers 15 and 16). The power conditioner 34 is used to detect an abnormality related to the power source of the control device 36 and the commercial power source 99 (numbers 17 and 18). The flow meter 156 is used for detecting an abnormality related to the amount of fuel m2 introduced (number 25). The flow meter 158 is used for detecting an abnormality related to the amount of combustion air a2 introduced (No. 26). The control device 36 is used to detect an abnormality related to the output of the air blower 29 and an abnormality related to the control device 36 itself (numbers 27 and 32). The flow meter 154 is used for detecting an abnormality related to the amount of the oxidant gas t introduced (number 28). The pressure gauge 157 is used for detecting an abnormality related to the original pressure of the fuel m (number 29). The gas detector 138 is used to detect the presence of combustible gas in the housing of the fuel cell 30 (number 30). The thermometer 139 is used for detecting an abnormality related to the temperature in the casing of the fuel cell 30 (number 31). Hereinafter, the operation of the fuel cell system 10 when an abnormality is detected will be described.

  FIG. 4 is a flowchart for explaining the operation of the fuel cell system 10 when an abnormality is detected. When the fuel cell system 10 is activated (S1), the control device 36 detects whether or not an abnormality has occurred by the above-described abnormality detection means (S2). Here, “being activated” means that an activation command is given to the fuel cell system 10. For example, whether or not the reformer 20 is generating the reformed gas g and whether the fuel cell 30 is It does not matter whether or not it is generating electricity. If no abnormality has occurred, the process returns to the step (S2) of detecting whether an abnormality has occurred again. When the occurrence of abnormality is detected, the operation of the fuel cell system 10 is immediately stopped (S3). When the fuel cell system 10 is stopped, as described above, the reformed gas g or the raw material m1 gas is enclosed in the reforming unit 21, the shift unit 22, and the selective oxidation unit 23 in order to prevent air from entering. Next, the control device 36 determines whether or not the generated abnormality is an abnormality relating to a predetermined minor failure (S4).

  Here, the abnormality relating to the predetermined minor failure is typically a transient abnormality that is likely to be resolved without performing manual maintenance. In the present embodiment, the temperature range in which the temperature in the reformer 20 (the reforming unit 21, the transformation unit 22, the selective oxidation unit 23) is allowed with respect to the physical quantity during steady operation as an abnormality related to a minor failure. Is too high or too low within a predetermined range (corresponding to numbers 2, 3, and 4 in FIG. 3), the temperature of the cooling water c led out to the cooling unit 33 of the fuel cell 30 is too high, or the flow rate. Is too small (corresponding to numbers 11, 12, and 13 in FIG. 3), the voltage of the power generated by the fuel cell 30 is too low, or the current deviates from the allowable range (number 15 in FIG. 3). , 16), an abnormality (corresponding to number 1 in FIG. 3) in which the flame of the burner 25b misfires is predetermined.

  These minor faults are determined in advance by the inventors of the present invention by finding the following points. An abnormality related to the temperature in the reforming unit 21 is a temporary malfunction in the supply system of the raw material m1 or the reforming water s (for example, a temporary malfunction of the reforming water pump 26 or the fuel blower 28, the raw material m1, the semi-reforming). This may be caused by a temporary deviating control due to a temporary blockage of the flow path of the gas r1, the modified gas r2, and the reforming water s). there is a possibility. In addition, when an abnormality occurs in the reforming unit 21 due to a temporary cause, it is considered that the modification unit 22 and / or the selective oxidation unit 23 communicating with the reforming unit 21 may be affected. If the abnormality in the unit 21 is resolved by the next start-up, there is a high possibility that the abnormality in the transformation unit 22 and / or the selective oxidation unit 23 is also resolved. However, when the temperature of the reforming unit 21 rises beyond a predetermined range (corresponding to number 22 in FIG. 3), the operation of the reformer 20 is stabilized from the start of the fuel cell system 10 to power generation. Since there are many cases that are not completed and may lead to a serious failure, it is not determined in advance as an abnormality related to a minor failure.

  The abnormality relating to the cooling water c is considered to be caused by a temporary malfunction of the cooling water pump 73, a temporary blockage of the cooling water pipes 74, 75, or air mixing into the cooling water pipes 74, 75. If this is the case, it may be resolved by the next startup. An abnormality in the power generation voltage of the fuel cell 30 that is too low is caused by a temporary supply failure of the reforming water s or a decrease in the activity of the selective oxidation catalyst 23c of the selective oxidation unit 23 of the reformer 20 to reduce the CO concentration in the reformed gas g. As a result, the cell is poisoned by CO, the reformed gas pipe 51 is momentarily closed, and the hydrogen supplied to the anode 31 is insufficient. The condensed water generated in the oxidant gas pipe 54 is brought into the cathode 32. This may be caused by a shortage of oxygen supplied to the cathode 32 due to a decrease in the cross-sectional area of the channel, and such an abnormality may not occur at the next startup. If the cause is a decrease in the activity of the selective oxidation catalyst 23c, the selective oxidation air a1 is supplied to the selective oxidation unit 23 when the temperature of the reforming unit 21 is raised to a temperature suitable for reforming, and is temporarily selected. The temperature is reduced by raising the temperature of the oxidation unit 23 to the active region, and then stopping the supply of the selective oxidation air a1 to make the selective oxidation unit 23 a reducing atmosphere (mainly hydrogen) until the next startup. there's a possibility that. In addition, an abnormality in the power generation voltage of the fuel cell 30 that is too low may be due to a temporary malfunction of the cells constituting the fuel cell 30 due to other causes. In such a case, there is a possibility that the abnormality will be resolved by the next startup. . The abnormality that the flame of the burner 25b was misfired was caused by instantaneous pressure fluctuations in the combustion section 25 during the combustion of the anode offgas p or water condensed in the anode offgas pipe 52 was temporarily brought into the burner 25b. Or when the fuel to be burned by the burner 25b is changed from the combustion fuel m2 to the reformed gas g or the anode offgas p, such an abnormality may not occur at the next start-up. .

  Abnormalities related to minor faults as described above may be resolved by the next start-up without performing manual maintenance, and if they are resolved, the fuel cell system 10 does not perform manual maintenance. Since the operation can be continued, the control device 36 determines whether or not the abnormality that has occurred is an abnormality relating to a predetermined minor failure (S4). In the step (S4) of determining whether or not the abnormality that has occurred is an abnormality related to a predetermined minor failure, if the abnormality is not related to a predetermined minor failure, the control device 36 is subjected to human maintenance. The control is performed so that the fuel cell system 10 is not restarted until the abnormality is reset due to the above, and an alarm signal is sent to a display device (not shown) that can be recognized by the user to generate an alarm and reset. The user is informed that the restart will not be performed (S9).

  On the other hand, if the abnormality is related to a predetermined minor failure, it is determined whether or not the abnormality having the same content has occurred for the first predetermined number of times during the first predetermined period (S5). Here, the first predetermined period is typically a period in which the abnormality is considered to be resolved at the latest if the abnormality that has occurred is a transient abnormality. In addition, the first predetermined number of times is typically the number of times that the abnormality is considered to be resolved by restarting the fuel cell system 10 if the abnormality that has occurred is a transient abnormality. The first predetermined period and the first predetermined number of times may be set to different values for each minor failure item. When the abnormality having the same content occurs for the first predetermined number of times in the first predetermined period, the control device 36 restarts the fuel cell system 10 until the abnormality is reset by performing manual maintenance. The alarm signal is sent to a display device (not shown) that can be recognized by the user, the alarm is issued, and the user is informed that the restart is not performed until reset (S9). .

  On the other hand, if an abnormality having the same content has not occurred for the first predetermined number of times during the first predetermined period, any of the abnormalities relating to a predetermined minor failure may occur during the second predetermined period. It is determined whether the number of times has occurred (S6). Here, the second predetermined period is typically a period that is considered to have been resolved at the latest, including an abnormality that has spread to other parts if the abnormality that has occurred is a transient abnormality. In addition, the second predetermined number of times is typically resolved by restarting the fuel cell system 10 including an abnormality that has spread to other parts if the abnormality that has occurred is a transient abnormality. It is a possible number of times. The first predetermined period and the second predetermined period may be arbitrarily set, and the first predetermined period and the second predetermined period may be the same period. Similarly, the first predetermined number of times and the second predetermined number of times may be set arbitrarily, and the first predetermined number of times and the second predetermined number of times may be the same. Typically, the second predetermined number is greater than the first predetermined number.

  In the step (S6) of determining whether any of the abnormalities relating to the predetermined minor failure has occurred a second predetermined number of times during the second predetermined period, the second predetermined period is determined during the second predetermined period. When the number of occurrences has occurred, the control device 36 performs control not to restart the fuel cell system 10 until the abnormality is reset by performing manual maintenance, and a display device (not shown) that can be recognized by the user. The alarm signal is sent to the user to notify the user that the system will not be restarted until it is reset (S9). On the other hand, if the second predetermined number of times has not occurred in the second predetermined period, the control device 36 determines whether or not a predetermined time has elapsed since the fuel cell system 10 was stopped (S3). (S7). Here, the predetermined time is typically a time required for the temperature of the reforming unit 21 to be lowered to a temperature at which the fuel cell system 10 can be restarted after being temporarily stopped. Instead of determining whether or not a predetermined time has elapsed, it may be configured to determine whether or not the temperature of the reforming unit 21 has decreased to a predetermined temperature. The predetermined temperature is typically the temperature of the reforming unit 21 at which the fuel cell system 10 can be restarted after being temporarily stopped.

  Note that the restart is not performed until a predetermined time has elapsed after the fuel cell system 10 is stopped (or until the temperature of the reforming unit 21 has decreased to a predetermined temperature). If the time from the stop to the next start is short from the state, the reformed gas g or the raw material m1 gas enclosed in the reforming unit 21 or the like before the temperature of the reforming unit 21 decreases is burner 25b. The temperature of the reforming unit 21 may become a high temperature exceeding the temperature during steady operation by being guided to the combustion process, and the temperature of the reforming unit 21 is an allowable temperature of the reforming catalyst 21c (for example, about 800). This is to avoid such inconvenience because the reforming catalyst 21c deteriorates when the temperature exceeds (° C.).

  In the step (S7) of determining whether or not a predetermined time has elapsed since the fuel cell system 10 was stopped (or whether or not the temperature of the reforming unit 21 has decreased to a predetermined temperature), the predetermined time When it has not elapsed (when the temperature of the reforming unit 21 has not decreased to a predetermined temperature), the process returns to the step of making this determination (S7) again. On the other hand, when the predetermined time has elapsed (when the temperature of the reforming unit 21 has decreased to the predetermined temperature), the fuel cell system 10 is restarted (S8). When the restart is performed, the fuel cell system 10 is again started (S1), and thereafter the above-described flow is repeated. In the above flow, step S5 and / or step S6 may be omitted. Further, instead of “determining whether or not the abnormality of the same content has occurred for the first predetermined number of times in the first predetermined period” instead of “the abnormality of the same content” It may be determined whether or not has occurred continuously for the first predetermined number of times. " Or it is good also as following the judgment which met conditions early, judging both simultaneously. Here, the “predetermined number of times” is typically resolved by restarting the fuel cell system 10 if the abnormality that has occurred is a transient abnormality as in the case of the first predetermined number of times. This is the number of times that can be considered, and a different number may be set for each minor failure item. Thus, when the abnormality is detected, the fuel cell system 10 according to the embodiment of the present invention stops the fuel cell system 10 regardless of whether or not the abnormality is an abnormality related to a minor failure. Will improve. Further, since the fuel cell system 10 is restarted when the detected abnormality is an abnormality related to a predetermined minor failure, maintenance can be omitted when the abnormality detected by the restart is resolved. If the abnormality is not resolved, the safety is improved because the operation is stopped again.

  Further, in the fuel cell system 10 including the reformer 20 and the fuel cell 30, a plurality of abnormalities may occur at the same time among the abnormalities as shown in FIG. It can be difficult. For example, when the generated power (output) of the fuel cell 30 decreases and the temperature of the reformer 20 temporarily decreases, and this abnormality induces another abnormality, it is difficult to specify the cause of the abnormality. In addition, an abnormal state may be temporarily indicated due to the influence of disturbance or the like. Since the fuel cell system 10 according to the embodiment of the present invention stops the fuel cell system 10 regardless of the content of the abnormality when the abnormality is detected, the stop process corresponding to the abnormality that has occurred is not performed. Well, the control is simplified. Even if multiple abnormalities are detected, if the detected abnormality is related to a minor failure, it will be restarted, and the generated abnormality is temporary and will be resolved by restarting. If it is, the operation can be continued and the maintenance can be omitted.

  In the above description, the abnormality related to the predetermined minor failure is assumed to be the abnormality corresponding to the numbers 1 to 4, 11 to 13, 15, and 16 shown in FIG. 3, but corresponds to the numbers 1 to 18 shown in FIG. The abnormality to be performed may be determined in advance as an abnormality relating to a minor failure. The inventors of the present invention have found that an abnormality other than the abnormality already described in the description of the operation of the fuel cell system 10 among the abnormality corresponding to the numbers 1 to 18 shown in FIG. This is due to the following findings.

  The abnormality related to the amount of the raw material m1 introduced (corresponding to the number 5 in FIG. 3) may be temporarily caused by a temporary control failure of the fuel blower 28 or a temporary failure of the flow meter 155F. If this is the case, it may be resolved by the next startup. An abnormality related to the introduction amount of the reforming water s (corresponding to the number 6 in FIG. 3) is caused by a temporary control failure of the reforming water pump 26 (temporary galling or the like) or a temporary inconvenience of the pressure gauge 196. It may have occurred temporarily, and in such a case, there is a possibility that it will be resolved by the next startup. The abnormality related to the temperature of the electric heater 13 (corresponding to the number 7 in FIG. 3) may be that a low electric power load lasted for a long time unexpectedly. There is. The abnormality (corresponding to the number 8 in FIG. 3) in which the level of the recovered water in the recovered water tank 96 has dropped may be due to temporary blockage of the recovered water pipes 91A to 94A. It may be resolved. An abnormality related to the flow rate of the heat storage water h (corresponding to the number 9 in FIG. 3) is a temporary inconvenience of the flow meter 183, a temporary trouble of the heat storage water pump 83, or a temporary blockage of the heat storage water pipes 84 and 85. In such a case, there is a possibility that it will be resolved by the next startup. Abnormalities related to the introduction amount of the selective oxidation air a1 (corresponding to the number 10 in FIG. 3) are temporary inconveniences of the flow meter 154, transient troubles of the air blower, temporary blockage of the selective oxidation air pipe 69, or the like. In such a case, there is a possibility that it will be resolved by the next startup.

  An abnormality related to the pressure of the reformed gas g (corresponding to the number 14 in FIG. 3) is a temporary control deviation of the reformer 20 or a loss of balance, or a temporary narrowing of the flow path of the reformed gas g (for example, one). An increase in the internal pressure of the cell of the fuel cell 30 due to a transient cause) can be considered, and in such a case, there is a possibility that it will be resolved by the next startup. The abnormality relating to the power source of the control device 36 (corresponding to the number 17 in FIG. 3) is a temporary abnormality of the system of the fuel cell 30 or the commercial power source 99, a decrease in the voltage of the fuel cell 30, or the voltage of the cell of the fuel cell 30. Has been found by experience that it can be restarted if these are the cause. An abnormality relating to the commercial power source 99 (corresponding to the number 18 in FIG. 3) may occur due to a temporary power failure of the commercial power source 99, and in such a case, there is a possibility that it will be resolved by the next startup. The above-described abnormalities relating to minor faults (abnormalities corresponding to numbers 1 to 18 shown in FIG. 3) may be stored in advance in the determination unit 36j as abnormalities relating to minor faults. These two or more abnormalities may be stored in the determination unit 36j in advance as abnormalities related to minor failures.

  On the other hand, the abnormality corresponding to the numbers 21 to 32 shown in FIG. 3 is avoided from being determined in advance as an abnormality relating to a minor failure for the following reasons (restart (not to perform the restart (step S8 in FIG. 4)). Is preferred. It is preferable not to restart the non-ignition of the flame of the burner 25b (corresponding to the number 21 in FIG. 3) because the flammable combustion fuel m2 may be discharged out of the system. An abnormality (corresponding to number 22 in FIG. 3) in which the temperature of the reforming unit 21 has risen beyond a predetermined range is the operation of the reformer 20 from the start of the fuel cell system 10 to power generation as described above. It is preferable not to restart the system because there are many cases where the system is not stable and may lead to a serious failure. The abnormality (corresponding to the number 23 in FIG. 3) related to the sealing pressure of the raw material m1 or the reformed gas g into the reformer 20 may cause a gas leak in the piping system or related equipment, and may not be restarted. preferable. If the recovered water level in the recovered water tank 96 is too high (corresponding to the number 24 in FIG. 3), there is a concern about the seat leak of the city water replenishing solenoid valve (not shown). Is preferred.

  It is preferable not to restart the abnormality related to the introduction amount of the combustion fuel m2 (corresponding to the number 25 in FIG. 3) because gas leakage in the piping system or related equipment or abnormal combustion in the burner 25b is concerned. An abnormality relating to the introduction amount of the combustion air a2 (corresponding to the number 26 in FIG. 3) and an abnormality relating to the output of the air blower 29 (corresponding to the number 27 in FIG. 3) are the leakage of the combustion air a2 in the piping system or related equipment, Alternatively, it is preferable not to restart the air blower 29 because there is a concern about failure of the air blower 29, which may cause abnormal combustion. An abnormality related to the introduction amount of the oxidant gas t (corresponding to the number 28 in FIG. 3) is likely to cause the combustion of the combustion air a2 in the piping system or related equipment, or the failure of the air blower 29, causing abnormal combustion. Therefore, it is preferable not to restart. An abnormality related to the original pressure of the fuel m (corresponding to the number 29 in FIG. 3) is considered to be a malfunction of the fuel m supply line, and it is considered difficult to restart the operation of the fuel cell system 10 unless resolved separately. It is preferable not to restart.

  When the presence of the combustible gas in the casing of the fuel cell 30 is detected (corresponding to the number 30 in FIG. 3), it is highly possible that the combustible gas has leaked, and it is preferable not to restart. An abnormality related to the temperature in the housing of the fuel cell 30 (corresponding to the number 31 in FIG. 3) may cause ignition if left untreated, so it is preferable not to restart. An abnormality in the control device 36 (corresponding to the number 32 in FIG. 3) is highly likely that the proper operation of the fuel cell system 10 cannot be continued. When the above-described abnormality corresponding to the numbers 21 to 32 shown in FIG. 3 is detected, a warning is typically issued without restarting the fuel cell system 10 (step S9 in FIG. 4). It becomes.

  In the above description, the fuel cell 30 has been described as a polymer electrolyte fuel cell, but may be a fuel cell other than a polymer electrolyte fuel cell such as a phosphoric acid fuel cell. However, the polymer electrolyte fuel cell can be operated at a relatively low temperature and can be downsized, so that it is suitable for installation in a general household.

1 is a schematic system diagram of a fuel cell system according to an embodiment of the present invention. It is a typical longitudinal cross-sectional view of a reformer. It is a figure explaining the relationship between the content of abnormality, and the member which comprises an abnormality detection means. It is a flowchart explaining operation | movement of the fuel cell system at the time of abnormality detection.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Fuel cell system 20 Reformer 30 Fuel cell 30E Output meter 36 Control apparatus 34 Power conditioner 25b Burner 99 Commercial power supply 125 Flame detector g Reformed gas

Claims (6)

A fuel cell system comprising a reformer that generates a reformed gas containing hydrogen, and a fuel cell that generates electricity by introducing the reformed gas;
An abnormality detecting means for detecting an abnormality of the fuel cell system;
A control device that stops the fuel cell system when the abnormality is detected, and that restarts the fuel cell system when the detected abnormality is an abnormality related to a predetermined minor failure;
Fuel cell system. The abnormality related to the minor failure is at least one of an abnormality related to a temperature distribution within a predetermined range in the reformer, an abnormality related to cooling water for cooling the fuel cell, and an abnormality related to a value of electric power generated by the fuel cell. Set to include one;
The fuel cell system according to claim 1. A power conditioner that converts DC power generated by the fuel cell into AC power and transmits the AC power to a power load, comprising a power conditioner linked to a commercial power source;
The abnormality detection means detects an abnormality related to the minor fault, detects a misfire of a burner in the reformer, and an overcurrent detector detects an overcurrent of a current flowing through the power conditioner. Having:
The fuel cell system according to claim 1 or 2. The control device is configured not to restart the fuel cell system when the abnormality detection unit detects an abnormality related to the minor failure having the same content for a first predetermined number of times in a first predetermined period. Was;
The fuel cell system according to any one of claims 1 to 3. The control device is configured not to restart the fuel cell system when the abnormality detecting means continuously detects an abnormality related to the minor failure having the same content for a predetermined number of times;
The fuel cell system according to any one of claims 1 to 3. The control device is configured not to restart the fuel cell system when the abnormality detection means detects an abnormality relating to the minor failure for a second predetermined number of times in a second predetermined period;
The fuel cell system according to any one of claims 1 to 5.

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