JP2014216168A - Fuel cell system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel cell system in which combustible gas is supplied to a gas detector for detecting carbon monoxide and at least one of notification or stopping of the gas supply to a combustor is performed according to a detection output of the gas detector.SOLUTION: Raw material gas supplied by a raw material supplier 4 or hydrogen-containing gas produced in a reformer 1 is detected by a gas detector 5 that detects carbon monoxide included in combustion exhaust gas exhausted from a combustor 2, at least one of noticing or stopping of the gas supply to the combustor 2 is performed according to a detection output, and thereby the safety of the gas detector can be determined while the safety of a fuel cell system 200 is maintained.

Description

  The present invention relates to a fuel cell system, and more particularly to a fuel cell system including a gas detector that detects carbon monoxide in combustion exhaust gas from a combustor.

  2. Description of the Related Art Conventionally, some fuel cell systems generate hydrogen by supplying a raw material mainly composed of a hydrocarbon-based combustible gas to a reformer and use it for power generation in a fuel cell stack. In such a fuel cell system, when combustible gas or hydrogen gas leaks into the package 4 from the raw material supply channel or the hydrogen-containing gas channel, a combustible gas detector 22 for detecting the leakage of the gas is provided. A fuel cell system 100 is known (see, for example, Patent Document 1).

  FIG. 10 is a block diagram showing a system configuration of the fuel cell system of Patent Document 1. As shown in FIG. In the package 18 of the fuel cell system, the fuel cell stack 7, the reformer 1 that supplies a hydrogen-containing gas, the combustible gas detector 22 that detects the leakage of the combustible gas in the package 18, and the raw material A combustible gas introduction pipe 4 for introducing a combustible gas and a control device 17 are provided, and the control device 17 intermittently injects the combustible gas from the combustible gas introduction pipe 4 to detect the combustible gas detector 22. The operation of the fuel cell system 100 is stopped based on the detected output.

Japanese Patent Laid-Open No. 2005-129491

  However, although a configuration in which a combustible gas is supplied to a gas detector that detects a combustible gas and the operation of the fuel cell system is stopped by a detection output is disclosed, it is included in the exhaust gas discharged from the reformer There is no disclosure of a configuration in which carbon monoxide is supplied to a gas detector that detects carbon monoxide, and at least one of notification and stop of gas supply to the combustor is performed based on the detection output. If carbon monoxide gas is injected into a gas detector that detects carbon monoxide contained in the exhaust gas, and at least one of notification and stop of gas supply to the combustor is performed according to the detection output Carbon monoxide, which is toxic to the human body, may be discharged outside the fuel cell system.

  In consideration of the above-described problems of the conventional fuel cell system, the present invention supplies a combustible gas to a gas detector that detects carbon monoxide, and performs notification and gas supply to the combustor according to the detection output. The purpose is to do at least one of the stops.

  In order to solve the above-mentioned conventional problems, the control device of the fuel cell system of the present invention detects carbon monoxide from a raw material gas supplied by a raw material supplier or a hydrogen-containing gas generated by a reformer. The gas detector is supplied, and at least one of notification and stop of gas supply to the combustor is performed according to the detection output.

  With the fuel cell system of the present invention, it is possible to determine the safety of a gas detector that detects carbon monoxide while maintaining the stability of the fuel cell system.

1 is a block diagram showing a configuration of a fuel cell system in Embodiment 1. FIG. The block diagram which shows the structure of the fuel cell system in the modification 1. FIG. 3 is a block diagram showing a configuration of a fuel cell system according to Embodiment 2. The block diagram which shows the structure of the fuel cell system in the modification 2. Block diagram showing a configuration of a fuel cell system according to Embodiment 3. The figure which shows the 1st output range of the gas detector which changes according to the density | concentration of source gas The block diagram which shows the structure of the fuel cell system in the modification 3. Block diagram showing a configuration of a fuel cell system according to Embodiment 4. FIG. 6 is a block diagram showing a configuration of a fuel cell system in a fifth embodiment. Block diagram showing the configuration of a conventional fuel cell system

  A fuel cell system according to a first aspect of the present invention includes a reformer that generates a hydrogen-containing gas from a raw material gas by a reforming reaction, and combusts at least one of the raw material gas and the hydrogen-containing gas, and a reforming catalyst in the reformer. A combustor that heats the gas generator, a fuel cell stack that generates power using the hydrogen-containing gas generated in the reformer, a raw material supplier that supplies the reformer with the raw material gas, and a combustion exhaust gas that is discharged from the combustor A gas detector for detecting carbon monoxide therein and a control device are provided. Then, the control device supplies the raw material gas supplied from the raw material supplier or the hydrogen-containing gas generated in the reformer to the gas detector, and notifies the gas to the combustor according to the detection output. At least one of the supply stops is performed. When the output of the gas detector deviates from an output value (for example, voltage) within a predetermined range with respect to the supplied gas concentration, or when there is no output, notification and stop of gas supply to the combustor Do at least one of these. Thereby, carbon monoxide that is toxic to the human body is not discharged to the outside of the fuel cell system, and at least one of notification and stop of gas supply to the combustor is performed according to the detection output of the gas detector. Can do.

  Further, when the source gas is supplied to the gas detector, after confirming the detection output of the gas detector, combustion can be started, so that the safety of the fuel cell system can be improved.

  According to a second invention, in the fuel cell system of the first invention, an air supply device for supplying air is further provided. In particular, the control device generates a mixed gas by mixing the air supplied from the air supply with the source gas, or mixing the air supplied from the air supply with the hydrogen-containing gas, The mixed gas is supplied to the gas detector, and at least one of notification and stop of gas supply to the combustor is performed according to the detection output of the gas detector. As a result, since the source gas or the hydrogen-containing gas is diluted with air, a gas having a sufficiently low concentration with respect to the combustible range is used, and the gas is supplied to the combustor according to the detection output of the gas detector. At least one of the stoppages can be performed.

  According to a third invention, in the fuel cell system of the second invention, a raw material flow meter for measuring a flow rate of a raw material gas supplied from the raw material supplier, and an air flow rate for measuring a flow rate of air supplied from the air supplier And a meter. Then, the control device uses the flow rate measured by the raw material flow meter, the flow rate measured by the air flow meter, and the detection output from the gas detector, and at least of the notification and the stop of the gas supply to the combustor. Do one. Thereby, at least one of notification and stop of gas supply to the combustor can be performed with higher accuracy. In addition, using the calculated amount of hydrogen generated by the reformer from the raw material gas flow rate measured by the raw material flow meter, the flow rate measured by the air flow meter, and the detection output from the gas detector, notification and At least one of the gas supply to the combustor is stopped. Thereby, at least one of notification and stop of gas supply to the combustor can be performed with higher accuracy.

  According to a fourth invention, in the fuel cell system of the third invention, the control device has a first output range for a gas concentration obtained from a flow rate measured by the raw material flow meter and a flow rate measured by the air flow meter, Compare the output value of the gas detector. Thereby, when the output value of the gas detector is out of the first output range, it can be detected as a decrease in the detection capability of the gas detector.

  According to a fifth invention, in any one of the first to third inventions, the fuel cell system further includes a temperature measuring device for measuring the temperature of the reformer. In particular, the raw material gas supplied from the raw material supplier passes through the reformer and is then supplied to the gas detector, and the controller measures the temperature measured by the temperature measuring device within a predetermined temperature range. The raw material gas that has passed through the reformer at the inside is supplied to the gas detector, and at least one of notification and stop of gas supply to the combustor is performed according to the detection output of the gas detector. Thereby, since the temperature of the reforming catalyst is known, it is possible to avoid a temperature zone in which the source gas is adsorbed / desorbed by the reforming catalyst and carbon deposition from the source gas occurs. Thereby, at least one of notification and stop of gas supply to the combustor can be performed with higher accuracy.

  A sixth invention is the fuel cell system according to any one of the first to third inventions, wherein the raw material gas supplied from the raw material supplier is supplied to the gas detector without passing through the reformer. Is provided. And a control apparatus performs at least one of a notification and the stop of the gas supply to a combustor according to the detection output of a gas detector using the raw material gas which passed the bypass flow path. As a result, since the determination is not performed until the measured value in the temperature measuring device falls within the predetermined temperature range, the raw material gas is not affected by adsorption / desorption by the catalyst in the reformer. In order to avoid the precipitation, at least one of the notification and the stop of the gas supply to the combustor can be performed with higher accuracy.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. This embodiment is an example, and the present invention is not limited to this embodiment.

(Embodiment 1)
The configuration of the fuel cell system in Embodiment 1 will be described with reference to FIG.

  FIG. 1 is a block diagram showing the configuration of the fuel cell system in the first embodiment. As shown in FIG. 1, the fuel cell system 200 includes a reformer 1, a combustor 2, a fuel cell stack 100, a raw material supplier 4, a gas detector 5, and a control device 6.

  The reformer 1 generates a hydrogen-containing gas from a raw material gas by a reforming reaction in a reforming catalyst section (not shown). A hydrogen-containing gas flow path 7, which will be described later, is connected to the outlet of the reformer 1, and the hydrogen-containing gas generated in the reformer 1 passes through the hydrogen-containing gas flow path 7 to the fuel cell stack 100. Supplied with.

  As a reforming method of the reformer 1, there is a steam reforming method in which a raw material gas is reacted with steam to generate carbon monoxide and hydrogen. Taking a steam reforming method as an example, although not shown in FIG. 1, an evaporator that generates steam and a water supply device that supplies water to the evaporator are provided. The source gas is a gas containing an organic compound composed of at least carbon and hydrogen, such as city gas mainly composed of methane, natural gas, and LPG. Alternatively, a partial oxidation method in which oxygen and a part of the source gas are reacted to obtain carbon monoxide and hydrogen, an autothermal reformer 1 that combines a steam reforming method and a partial oxidation method, or the like may be used. .

  The fuel cell stack 100 generates power by chemically reacting a hydrogen-containing gas generated in the reformer 1 and air (oxidant gas) supplied from a first air supplier 3 described later. .

  The combustor 2 heats the reforming catalyst portion in the reformer 1 by burning at least one of a raw material gas, a hydrogen-containing gas, and an anode off gas (exhaust hydrogen). The flue gas generated by this combustion is discharged to the outside through a flue gas passage 15 which will be described later.

  The first air supplier 3 supplies air from the outside of the fuel cell system 200 to the fuel cell stack 100. A first air flow path 13 extends from the first air supplier 3, and one end of the first air flow path 13 is connected to the oxygen electrode 14 of the fuel cell stack 100.

  The raw material supplier 4 is arranged in the middle of the raw material gas flow path 27 and supplies the raw material gas from the outside of the fuel cell system 200 to the reformer 1. As the source gas, methane or propane supplied from city gas or LP gas can be used. A raw material gas main valve 16 that opens and closes the flow path is disposed upstream of the raw material supplier 4.

  The gas detector 5 is disposed in the middle of a later-described combustion exhaust gas passage 15 and detects carbon monoxide in the combustion exhaust gas discharged from the combustor 2. As a system of the gas detector 5, for example, a catalytic combustion type or a semiconductor type can be adopted. Here, the catalytic combustion type gas detector 5 has two heater coils, and a detection element added with a catalyst and a compensation element not added with a catalyst are attached to each heater coil. The heater coil is used to raise the temperature to an appropriate temperature for the element to perform a catalytic reaction. When a gas containing carbon monoxide or hydrocarbon touches the detection element of the gas detector 5, catalytic combustion occurs in the detection element, combustion heat is generated, and the temperature of the detection element rises. The gas detector 5 outputs a temperature difference (resistance difference) between the two elements of the detection element and the compensation element as an electrical signal. Since the temperature of the sensing element increases according to the concentration of carbon monoxide, there is a proportional relationship in which the output value increases as the carbon monoxide concentration increases. In the present embodiment, the gas detector 5 is disposed in the middle of the flow path of the combustion exhaust gas flow path 15. However, the present invention is not limited to this, and the gas detector 5 may be disposed inside the combustor 2. good.

  The control device 6 appropriately controls the first air supplier 3, the raw material supplier 4, the gas detector 5, the first valve 10, and the second valve 11 that constitute the fuel cell system 200. The first air supplier 3, the raw material supplier 4, the gas detector 5, the first valve 10, and the second valve 11 constituting the control device 6 and the fuel cell system 200 are signal lines (not shown) in FIG. Are connected to each other. Thereby, the fuel cell system 200 operates.

  The hydrogen-containing gas flow path 7 supplies the hydrogen-containing gas generated by the reformer 1 to the fuel cell stack 100. Specifically, one end of the hydrogen-containing gas flow path 7 is connected to the outlet of the reformer 1, and the other end is connected to the hydrogen electrode 8 of the fuel cell stack 100. The hydrogen-containing gas channel 7 is provided with a first valve 10 for opening and closing the channel.

  The exhaust hydrogen flow passage 9 supplies the anode off gas discharged from the fuel cell stack 100 to the combustor 2. Specifically, one end of the exhaust hydrogen passage 9 is connected to the hydrogen electrode 8 of the fuel cell stack 100, and the other end is connected to the combustor 2.

  The first bypass flow path 12 supplies the hydrogen-containing gas generated in the reformer 1 to the combustor 2 without passing through the fuel cell stack 100. Specifically, the first bypass flow path 12 is branched from the hydrogen-containing gas flow path 7 and connected to the exhaust hydrogen flow path 9. The first bypass channel 12 is provided with a second valve 11 for opening and closing the channel.

The combustion exhaust gas flow path 15 discharges the combustion exhaust gas generated by the combustion in the combustor 2 to the outside of the fuel cell system 200. A gas detector 5 is installed in the middle of the combustion exhaust gas passage 15.

  The exhaust air flow path 17 discharges the exhaust air discharged from the fuel cell stack 100 to the outside. Specifically, one end of the exhaust air passage 17 is connected to the outlet of the oxygen electrode 14 of the fuel cell stack 100, and the other end is connected to the combustion exhaust gas passage 15 extending from the combustor 2. ing.

  Next, operations for generating a hydrogen-containing gas used for power generation in the fuel cell system 200 and operations for generating power by the fuel cell system 200 will be described in order with reference to the drawings.

  When the fuel cell system 200 according to Embodiment 1 is started, the control device 6 opens the raw material gas main valve 16, closes the first valve 10, and opens the second valve 11, and then operates the raw material supplier 4. Then, the supply of the raw material gas is started. The raw material gas passes through the interior of the reformer 1 and is supplied to the combustor 2 through the hydrogen-containing gas flow path 7, the first bypass flow path 12, and the exhaust hydrogen flow path 9. In the combustor 2, the raw material gas is burned using the air supplied by the air supply device (not shown). Note that the combustion exhaust gas generated by the combustion is discharged from the fuel cell system 200 through the combustion exhaust gas passage 15.

  When the temperature of the reformer 1 is increased by combustion in the combustor 2, reforming water is supplied to the reformer 1 from a reforming water supply device (not shown), and a reforming reaction starts. Here, at the start of the reforming reaction, a sufficient amount of hydrogen required for the power generation by the fuel cell stack 100 is not generated in the reformer 1, and the hydrogen-containing gas supplied from the reformer 1 has a certain amount of hydrogen. Contains catalyst poisoning components such as carbon oxides. Therefore, when the fuel cell system 200 is activated, the control device 6 operates the first valve 10 and the second valve 11 to connect the hydrogen-containing gas flow path 7 and the exhaust hydrogen flow path 9 to the first bypass flow path. The hydrogen-containing gas with a low hydrogen content is bypassed the fuel cell stack 100 and supplied to the combustor 2 so as to be used for combustion.

  When the reformer 1 is sufficiently heated to generate enough hydrogen for power generation, the control device 6 opens the first valve 10 and closes the second valve 11 to switch the flow path, thereby containing hydrogen. Gas is supplied to the fuel cell stack 100. The hydrogen-containing gas flows through the hydrogen-containing gas flow path 7 and is supplied to the hydrogen electrode 8 of the fuel cell stack 100. On the other hand, the air sent out from the first air supplier 3 flows through the first air flow path 13 and is supplied to the oxygen electrode 14 of the fuel cell stack. Then, in the fuel cell stack 100, the supplied hydrogen-containing gas and air are used, and an electrochemical reaction between hydrogen in the hydrogen-containing gas and oxygen in the air is performed. Predetermined power is output from the fuel cell stack 100. Excess exhaust air that has not been used in the electrochemical reaction is discharged to the outside of the fuel cell system 200 through the exhaust air passage 17 and the combustion exhaust passage 15. In addition, surplus anode off-gas that has not been used for the electrochemical reaction flows through the exhaust hydrogen passage 9 and is supplied to the combustor 2 to be used as heating fuel for the reforming reaction. Further, when the gas detector 5 provided in the combustion exhaust gas flow path 15 detects carbon monoxide gas, the control device 6 shuts off the raw material gas main valve 16 and stops the operation of the fuel cell system 200.

  Next, a method for performing at least one of notification and stopping of gas supply to the combustor 2 in accordance with the detection output of the gas detector 5 in the fuel cell system 200 according to Embodiment 1 of the present invention will be described. The description will be given with reference.

First, when supplying the raw material gas to the gas detector 5, the control device 6 opens the raw material gas main valve 16 and closes the first valve 10 before performing combustion in the combustor 2 at the time of startup, for example. After opening the second valve 11, the raw material supplier 4 is operated. Thus, the raw material gas passes through the reformer 1, the hydrogen-containing gas flow path 7, the first bypass flow path 12, the exhaust hydrogen flow path 9, and the combustor 2, and is installed in the combustion exhaust gas flow path 15. It is supplied to the detector 5.

  At this time, if the output value V of the gas detector 5 with respect to the supplied raw material gas is within a predetermined range, that is, V1 <V ≦ V2, the control device 6 continues the operation of the fuel cell system 200 (V1 is For example, it is the minimum output value when the gas detector 5 is energized, and V2 is the maximum value output by the gas detector 5 at the concentration of the source gas to be supplied). However, if the detection sensitivity of the carbon monoxide of the gas detector 5 is lowered or sensitive due to deterioration of the gas detector 5 over time, the raw material gas is supplied to the gas detector 5 as described above. Also, the output value of the gas detector 5 deviates from the output within the predetermined range. At this time, the control device 6 takes appropriate safety measures for ensuring the safety of the fuel cell system 200. Examples of the safety measures include stopping the operation of the fuel cell system 200 by stopping the gas supply to the combustor 2 and notifying the user of the fuel cell system 200 of the abnormality of the gas detector 5. The control device 6 may take appropriate safety measures for ensuring the safety of the fuel cell system 200 after determining that the gas detector 5 is not operating.

  As described above, when the configuration of the fuel cell system 200 in the present embodiment is taken, at least of the notification and the stop of the gas supply to the combustor 2 according to the detection output of the gas detector 5 using the raw material gas. One can do it.

(Modification 1)
A first modification of the fuel cell system in the first embodiment will be described with reference to FIG. FIG. 2 is a block diagram showing the configuration of the fuel cell system in the first modification. The fuel cell system 200 shown in FIG. 2 is different from the first embodiment in that the second bypass flow path 31 and the fifth valve 30 are provided. The second bypass flow path 31 supplies the hydrogen-containing gas generated by the reformer 1 to the gas detector 5. The second bypass channel 31 is provided with a fifth valve 30 for opening and closing the channel.

First, when supplying the hydrogen-containing gas to the gas detector 5, for example, when the reformer 1 is generating hydrogen, the control device 6 opens the fifth valve 30 and supplies the hydrogen-containing gas to the gas detector 5. To supply. As a result, the hydrogen-containing gas is supplied to the gas detector 5 through the reformer 1, the hydrogen-containing gas flow path 7, and the second bypass flow path 31. At this time, if the output value V of the gas detector 5 with respect to the supplied raw material gas is within a predetermined range V1 <V ≦ V2, the control device 6 continues the operation of the fuel cell system 200 (V1 is, for example, The minimum output value when the gas detector 5 is energized, and V2 is the maximum value output from the gas detector 5 at the concentration of the supplied raw material gas). However, when the gas detector 5 is deteriorated in sensitivity or detection sensitivity of carbon monoxide due to aging or the like, a hydrogen-containing gas is supplied to the gas detector 5 as described above. However, the output value of the gas detector 5 deviates from the output within the predetermined range. At this time, the control device 6 takes appropriate safety measures for ensuring the safety of the fuel cell system 200. Examples of the safety measures include stopping the operation of the fuel cell system 200 by stopping the gas supply to the combustor 2 and notifying the user of the fuel cell system 200 of the abnormality of the gas detector 5. The control device 6 may take appropriate safety measures for ensuring the safety of the fuel cell system 200 after determining that the gas detector 5 is not operating.
In addition, in this modification, when supplying raw material gas to the gas detector 5, according to the detection output of the gas detector 5, without operating the reformer 1 and the combustor 2, it notifies to the combustor 2. At least one of the gas supply stops can be performed. In this case, since the combustion can be started after the detection output of the gas detector 5 is confirmed, the safety of the fuel cell system 200 can be improved.

(Embodiment 2)
The configuration of the fuel cell system according to Embodiment 2 will be described with reference to FIG. FIG. 3 is a block diagram showing the configuration of the fuel cell system in the second embodiment. In addition, the same code | symbol is provided about the component similar to Embodiment 1, and the description is abbreviate | omitted here.

  The fuel cell system 200 shown in FIG. 3 includes a second air flow path 18 that is connected to the combustor 2 from the second air supply device 24, and a second air that supplies air to the combustor 2 via the second air flow path 18. This embodiment is different from the first embodiment in that an air supply device 24 is provided.

  First, when supplying the raw material gas and air mixed gas to the gas detector 5, the control device 6 opens the raw material gas main valve 16 and ignites the first valve 10, for example, before ignition in the combustor 2 at start-up. Is closed and the second valve 11 is opened, the raw material supplier 4 is operated, and the supply of the raw material gas is started. Further, the control device 6 operates the second air supply unit 24 to supply air from the second air flow path 18 to the combustor 2. As a result, the raw material gas passes through the interior of the reformer 1 and is supplied to the combustor 2 through the hydrogen-containing gas flow path 7, the first bypass flow path 12, and the exhaust hydrogen flow path 9.

  In the combustor 2, the raw material gas and air are mixed and diluted. The mixed gas mixture is supplied to the gas detector 5 installed in the combustion exhaust gas passage 15. At this time, if the output value V of the gas detector 5 with respect to the supplied mixed gas is within a predetermined range V1 <V ≦ V2, the control device 6 continues the operation of the fuel cell system 200 (V1 is, for example, The minimum output value when the gas detector 5 is energized, and V2 is the maximum value output from the gas detector 5 at the concentration of the supplied raw material gas). However, if the gas detector 5 has low or sensitive carbon monoxide detection sensitivity due to deterioration over time, the mixed gas is supplied to the gas detector 5 as described above. Also, the output value of the gas detector 5 deviates from the output within the predetermined range. At this time, the control device 6 takes appropriate safety measures for ensuring the safety of the fuel cell system 200. Examples of the safety measures include stopping the operation of the fuel cell system 200 by stopping the gas supply to the combustor 2 and notifying the user of the fuel cell system 200 of the abnormality of the gas detector 5. The control device 6 may take appropriate safety measures for ensuring the safety of the fuel cell system 200 after determining that the gas detector 5 is not operating.

  When the configuration of the fuel cell system 200 according to the second embodiment is taken, the raw material gas is diluted with air, so that a sufficiently low concentration gas is used with respect to the combustible range, and the gas detector 5 is used in accordance with the detection output. In addition, at least one of the notification and the stop of the gas supply to the combustor 2 can be performed. In FIG. 3, the raw material gas and air are mixed in the combustor 2. However, the present invention is not limited to this. For example, the gas may be mixed in the middle of the combustion exhaust gas flow path 15.

(Modification 2)
Modification 2 of the fuel cell system in Embodiment 2 will be described with reference to FIG. FIG. 4 is a block diagram showing the configuration of the fuel cell system in Modification 2. The fuel cell system 200 shown in FIG. 4 supplies a mixed gas of hydrogen-containing gas and air to the gas detector 5 and performs at least one of notification and stop of the combustor 2.

  The fuel cell system 200 shown in FIG. 4 includes the second bypass passage 31 and the fifth valve 30, and the fuel cell shown in FIG. 3 in that the second air passage 18 is connected to the second bypass passage 31. Different from the system 200. The second bypass flow path 31 supplies the hydrogen-containing gas generated by the reformer 1 to the gas detector 5. The second bypass channel 31 is provided with a fifth valve 30 for opening and closing the channel.

First, when supplying a mixed gas of hydrogen-containing gas and air to the gas detector 5, the control device 6 opens the fifth valve 30, for example, when the reformer 1 is generating hydrogen, and opens the hydrogen-containing gas. Is supplied to the gas detector 5. Further, the control device 6 operates the second air supply device 24 to supply air from the second air flow path 18 to the combustor 2. At this time, the hydrogen-containing gas is mixed with air in the flow path and diluted. The mixed gas mixture is supplied to the gas detector 5. At this time, if the output value V of the gas detector 5 with respect to the supplied mixed gas is within a predetermined range V1 <V ≦ V2, the control device 6 continues the operation of the fuel cell system 200 (V1 is, for example, The minimum output value when the gas detector 5 is energized, and V2 is the maximum value output from the gas detector 5 at the concentration of the supplied raw material gas). However, if the gas detector 5 has low or sensitive carbon monoxide detection sensitivity due to deterioration over time, the mixed gas is supplied to the gas detector 5 as described above. However, the output value of the gas detector 5 deviates from the output within the predetermined range or there is no output. At this time, the control device 6 takes appropriate safety measures for ensuring the safety of the fuel cell system 200. Examples of the safety measures include stopping the operation of the fuel cell system 200 by stopping the gas supply to the combustor 2 and notifying the user of the fuel cell system 200 of the abnormality of the gas detector 5. The control device 6 may take appropriate safety measures for ensuring the safety of the fuel cell system 200 after determining that the gas detector 5 is not operating.

(Embodiment 3)
The configuration of the fuel cell system according to Embodiment 3 will be described with reference to FIG. FIG. 5 is a block diagram showing the configuration of the fuel cell system in the third embodiment. In addition, the same code | symbol is provided about the component similar to Embodiment 1-2, and the description is abbreviate | omitted here.

  In the fuel cell system 200 shown in FIG. 5, a raw material flow meter 20 that measures the flow rate of the raw material gas supplied to the reformer 1, and an air flow meter 21 that measures the flow rate of air supplied to the combustor 2, Is further different from the first and second embodiments.

  First, when supplying the mixed gas of raw material gas and air to the gas detector 5, the control device 6 opens the raw material gas main valve 16 and opens the first valve 10, for example, before ignition in the combustor 2 at start-up. After closing and opening the second valve 11, the raw material supplier 4 is operated and the supply of the raw material gas is started. At this time, the raw material gas having a flow rate controlled by the control device 6 based on the value measured by the raw material flow meter 20 is supplied to the combustor 2. The control device 6 operates the second air supply device 24 and supplies air from the second air flow path 18 to the combustor 2 based on the flow rate measured by the air flow meter 21.

  In the combustor 2, the raw material gas is mixed with air and diluted. The diluted mixed gas is supplied to the gas detector 5 installed in the combustion exhaust gas flow path 15. At this time, if the output value V of the gas detector 5 with respect to the supplied mixed gas is within a predetermined range V1 <V ≦ V2, the control device 6 continues the operation of the fuel cell system 200 (V1 is, for example, The minimum output value when the gas detector 5 is energized). However, if the gas detector 5 has low or sensitive carbon monoxide detection sensitivity due to deterioration over time, the mixed gas is supplied to the gas detector 5 as described above. However, the output value of the gas detector 5 deviates from the output within the predetermined range or there is no output. At this time, the control device 6 takes appropriate safety measures for ensuring the safety of the fuel cell system 200. Examples of the safety measures include stopping the operation of the fuel cell system 200 by stopping the gas supply to the combustor 2 and notifying the user of the fuel cell system 200 of the abnormality of the gas detector 5. The control device 6 may take appropriate safety measures for ensuring the safety of the fuel cell system 200 after determining that the gas detector 5 is not operating.

Here, since the mixed gas concentration is known from the flow rate measured by the raw material flow meter 20 and the flow rate measured by the air flow meter 21, the output value V of the gas detector 5 with respect to this mixed gas concentration is
You may confirm operation | movement of the gas detector 5 by whether it becomes a predetermined true value. FIG. 6 is a diagram showing the relationship between the mixed gas concentration and the output value of the gas detector 5. L indicates the true output value of the gas detector 5 with respect to the raw material gas concentration.
If the output value from the gas detector 5 is within a predetermined error range (for example, ± 5 mV) from the true value determined by the gas concentration, the control device 6 continues the operation of the fuel cell system 200. Thereby, the operation check of the gas detector 5 can be performed with higher accuracy.

  The output range changes according to the concentration of the mixed gas. The control device 6 compares the output value of the gas detector 5 with the first output range, and when the control device 6 is out of the first output range, the control device 6 ensures the safety of the fuel cell system 200. Take appropriate safety measures. Examples of the safety measures include stopping the operation of the fuel cell system 200 by stopping the gas supply to the combustor 2 and notifying the user of the fuel cell system 200 of the abnormality of the gas detector 5. The control device 6 may take appropriate safety measures for ensuring the safety of the fuel cell system 200 after determining that the gas detector 5 is not operating.

  As described above, when the configuration of the fuel cell system 200 in the present embodiment is taken, at least one of notification and stop of gas supply to the combustor 2 can be performed according to the detection output of the gas detector 5. In addition, it is possible to detect a decrease in the detection capability of the gas detector 5.

(Modification 3)
A third modification of the fuel cell system in the third embodiment will be described with reference to FIG. FIG. 7 is a block diagram showing the configuration of the fuel cell system in Modification 3. The fuel cell system 200 shown in FIG. 7 is different from FIG. 5 in that it includes a second bypass passage 31 and a fifth valve 30 and the second air passage 18 is connected to the second bypass passage 31. . The second bypass flow path 31 supplies the hydrogen-containing gas generated by the reformer 1 to the gas detector 5. The second bypass channel 31 is provided with a fifth valve 30 for opening and closing the channel.

  First, when supplying a mixed gas of hydrogen-containing gas and air to the gas detector 5, the control device 6 opens the fifth valve 30, for example, when the reformer 1 is generating hydrogen, and opens the hydrogen-containing gas. Is supplied to the gas detector 5. The second air supply unit 24 is operated to supply air from the second air flow path 18 to the second bypass flow path 31. At this time, the hydrogen-containing gas is mixed with air in the flow path and diluted. The mixed mixed hydrogen-containing gas is supplied to the gas detector 5. At this time, the raw material gas having a flow rate controlled by the control device 6 based on the value measured by the raw material flow meter 20 is supplied to the reformer 1, and the hydrogen generation amount is calculated based on the temperature of the reforming catalyst. The control device 6 operates the second air supply device 24, and air is supplied to the second bypass passage 31 based on the flow rate measured by the air flow meter 21. At this time, if the output value V of the gas detector 5 with respect to the supplied mixed gas is within a predetermined range V1 <V ≦ V2, the control device 6 continues the operation of the fuel cell system 200 (V1 is, for example, The minimum output value when the gas detector 5 is energized). However, if the gas detector 5 has low or sensitive carbon monoxide detection sensitivity due to deterioration over time, the mixed gas is supplied to the gas detector 5 as described above. However, the output value of the gas detector 5 deviates from the output within the predetermined range or there is no output. At this time, the control device 6 takes appropriate safety measures for ensuring the safety of the fuel cell system 200. Examples of the safety measures include stopping the operation of the fuel cell system 200 by stopping the gas supply to the combustor 2 and notifying the user of the fuel cell system 200 of the abnormality of the gas detector 5. The control device 6 may take appropriate safety measures for ensuring the safety of the fuel cell system 200 after determining that the gas detector 5 is not operating.

Here, since the mixed gas concentration is known from the flow rate measured by the raw material flow meter 20 and the flow rate measured by the air flow meter 21, the output value V of the gas detector 5 with respect to this mixed gas concentration is
You may confirm operation | movement of the gas detector 5 by whether it becomes a predetermined true value. FIG. 6 is a diagram showing the relationship between the mixed gas concentration and the output value of the gas detector 5. L indicates the true output value of the gas detector 5 with respect to the raw material gas concentration.

  If the output value from the gas detector 5 is within a predetermined error range (for example, ± 5 mV) from the true value determined by the gas concentration, the control device 6 continues the operation of the fuel cell system 200. Thereby, the operation check of the gas detector 5 can be performed with higher accuracy.

  The output range changes according to the concentration of the mixed gas. The control device 6 compares the output value of the gas detector 5 with the first output range, and when the control device 6 is out of the first output range, the control device 6 ensures the safety of the fuel cell system 200. Take appropriate safety measures. Examples of the safety measures include stopping the operation of the fuel cell system 200 by stopping the gas supply to the combustor 2 and notifying the user of the fuel cell system 200 of the abnormality of the gas detector 5. The control device 6 may take appropriate safety measures for ensuring the safety of the fuel cell system 200 after determining that the gas detector 5 is not operating.

  As described above, when the configuration of the fuel cell system 200 in the present embodiment is taken, at least one of notification and stop of gas supply to the combustor 2 can be performed according to the detection output of the gas detector 5. it can.

(Embodiment 4)
The configuration of the fuel cell system according to Embodiment 4 will be described with reference to FIG. FIG. 8 is a block diagram showing the configuration of the fuel cell system in the fourth embodiment. In addition, the same code | symbol is provided about the component similar to Embodiment 1-3, The description is abbreviate | omitted here.

  The fuel cell system 200 shown in FIG. 8 further includes a temperature measuring device 22 that measures the temperature of the reformer 1, and the control device 6 is configured to supply a raw material when the temperature measured by the temperature measuring device 22 is within a predetermined range. The difference from Embodiments 1 to 3 is that gas is supplied to the reformer 1.

  First, when supplying the mixed gas of raw material gas and air to the gas detector 5, the control device 6 measures the temperature of the reformer 1 with the temperature measuring device 22. At this time, when the measured temperature is within a predetermined temperature range, the raw material gas main valve 16 is opened, the first valve 10 is closed, the second valve 11 is opened, the raw material supplier 4 is operated, and the raw material gas is Start supplying. At this time, the raw material gas having a flow rate controlled by the control device 6 based on the value measured by the raw material flow meter 20 is supplied to the combustor 2. Further, the second air supply unit 24 is operated, and air is supplied from the second air flow path 18 to the combustor 2 based on the flow rate measured by the air flow meter 21.

  Here, the predetermined temperature range is a temperature range where hydrocarbons are not adsorbed / desorbed in the reforming catalyst, and a temperature range where carbon deposition does not occur from the raw material gas. For example, the temperature range where hydrocarbons are not adsorbed / desorbed in the reforming catalyst is about 50 ° C. or more and less than 70 ° C. for propane or butane. When the temperature of the reformer 1 is lower than the predetermined temperature range, the hydrocarbon is adsorbed by the catalyst in the reformer 1 and desorbed to the catalyst when the temperature is higher than the predetermined temperature range, so that the concentration of the raw material gas is not stable. Further, since the source gas starts to precipitate when the temperature is about 400 ° C. or higher, the gas composition is affected and the concentration of the source gas is not stable. At this time, the control device 6 does not supply the raw material gas to the reformer 1 until the value measured by the temperature measuring device 22 falls within a predetermined temperature range.

As described above, when the configuration of the fuel cell system 200 in the present embodiment is adopted, the temperature measuring device 22 measures the temperature of the reformer 1, and thereby the temperature at which the raw material gas is adsorbed / desorbed by the reforming catalyst. The source gas can be supplied to the gas detector 5 while avoiding the band. Thereby, according to the detection output of the gas detector 5, the precision which performs at least one among notification and the stop of the combustor 2 can be raised. When the output value of the gas detector 5 deviates from the output within the predetermined range or there is no output, the control device 6 takes appropriate safety measures for ensuring the safety of the fuel cell system 200. Examples of the safety measures include stopping the operation of the fuel cell system 200 by stopping the gas supply to the combustor 2 and notifying the user of the fuel cell system 200 of the abnormality of the gas detector 5. The control device 6 may take appropriate safety measures for ensuring the safety of the fuel cell system 200 after determining that the gas detector 5 is not operating. In addition, although the effect given to Embodiment 3 was demonstrated, the same effect is acquired also in Embodiment 1 or Embodiment 2.

(Embodiment 5)
The configuration of the fuel cell system according to Embodiment 5 will be described with reference to FIG. FIG. 9 is a block diagram showing the configuration of the fuel cell system in the fifth embodiment. In addition, the same code | symbol is provided about the component similar to Embodiment 1-4, The description is abbreviate | omitted here.

  In the fuel cell system 200 shown in FIG. 9, a raw material gas bypass passage 23 for supplying the raw material gas supplied from the raw material supplier 4 to the gas detector 5 without passing through the reformer 1, and the raw material gas bypass The fourth embodiment differs from the first to fourth embodiments in that it further includes a fourth valve 26 that opens and closes the flow path 23 and a third valve 25 that opens and closes the source gas flow path 27.

  A raw material gas bypass passage 23 for supplying the raw material gas supplied from the raw material supplier 4 to the gas detector 5 without passing through the reformer 1 is provided downstream of the raw material supplier 4 and is a raw material gas bypass passage. The outlet of 23 is connected to the combustor 2. Then, the control device 6 supplies the raw material gas that has passed through the raw material gas bypass passage 23 to the gas detector 5.

  As described above, when the configuration of the fuel cell system 200 according to the present embodiment is adopted, the raw material gas is not affected by the adsorption / desorption of the raw material gas by the catalyst in the reformer 1 or the carbon deposition of the raw material gas. Gas can be supplied to the gas detector 5. That is, regardless of the temperature of the reformer 1, at least one of notification and stop of the combustor 2 can be performed according to the detection output of the gas detector 5. When the output value of the gas detector 5 deviates from the output within the predetermined range or there is no output, the control device 6 takes appropriate safety measures for ensuring the safety of the fuel cell system 200. Examples of the safety measures include stopping the operation of the fuel cell system 200 by stopping the gas supply to the combustor 2 and notifying the user of the fuel cell system 200 of the abnormality of the gas detector 5. The control device 6 may take appropriate safety measures for ensuring the safety of the fuel cell system 200 after determining that the gas detector 5 is not operating.

  The fuel cell system of the present invention is useful for ensuring the safety of a system in which a gas detector for detecting carbon monoxide is mounted in a combustion exhaust gas passage.

DESCRIPTION OF SYMBOLS 1 Reformer 2 Combustor 3 1st air supply device 4 Raw material supply device 5 Gas detector 6 Control apparatus 7 Hydrogen containing gas flow path 8 Hydrogen electrode 9 Exhaust hydrogen flow path 10 1st valve 11 2nd valve 12 1st bypass Flow path 13 First air flow path 14 Oxygen electrode 15 Combustion exhaust gas flow path 16 Raw material gas main valve 17 Exhaust air flow path 18 Second air flow path 20 Raw material flow meter 21 Air flow meter 22 Temperature meter 23 Raw material gas bypass flow path 24 2nd air supply device 25 3rd valve 26 4th valve 27 Raw material gas flow path 30 5th valve 31 2nd bypass flow path 100 Fuel cell stack 200 Fuel cell system

Claims (7)

A reformer that generates a hydrogen-containing gas from a raw material gas by a reforming reaction;
A combustor that combusts at least one of the source gas and the hydrogen-containing gas and heats the reforming catalyst unit in the reformer;
A fuel cell stack that generates electricity using the hydrogen-containing gas generated in the reformer;
A raw material supplier for supplying a raw material gas to the reformer;
A gas detector for detecting carbon monoxide in the combustion exhaust gas discharged from the combustor;
A control device,
The control device supplies a raw material gas supplied from the raw material supply device or a hydrogen-containing gas generated by the reformer to the gas detector, and notifies according to a detection output of the gas detector. And at least one of stopping the gas supply to the combustor. An air supply for supplying air;
The control device generates a mixed gas by mixing the air supplied from the air supplier to the source gas, or mixing the air supplied from the air supplier to the hydrogen-containing gas,
2. The fuel cell system according to claim 1, wherein the mixed gas is supplied to the gas detector, and at least one of notification and stop of gas supply to the combustor is performed according to a detection output of the gas detector. . A raw material flow meter for measuring the flow rate of the raw material gas supplied from the raw material supply device, and an air flow meter for measuring the flow rate of air supplied from the air supply device,
The control device uses the flow rate measured by the raw material flow meter, the flow rate measured by the air flow meter, and the output from the gas detector to notify and stop gas supply to the combustor. The fuel cell system according to claim 2, wherein at least one is performed. 4. The control device according to claim 1, wherein when the output value of the gas detector is out of a first output range, the control device performs at least one of notification and stop of gas supply to the combustor. 5. The fuel cell system described in 1. The fuel cell system according to claim 4, wherein the first output range changes according to a concentration of the raw material gas. A temperature measuring device for measuring the temperature of the reformer;
The raw material gas supplied from the raw material supplier is supplied to the gas detector after passing through the reformer,
The control device supplies the raw material gas to the reformer when the temperature measured by the temperature measuring device is within a predetermined temperature range, and notifies and combusts according to the detection output of the gas detector. The fuel cell system according to any one of claims 1 to 5, wherein at least one of the gas supply is stopped. Further comprising a bypass channel disposed so that the source gas supplied from the source supply unit can be supplied to the gas detector without passing through the reformer,
The said control apparatus performs at least one of notification and the stop of the gas supply to the said combustor according to the detection output of the said gas detector using the raw material gas which passed the said bypass flow path. 6. The fuel cell system according to any one of items 1 to 5.

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