JP4830528B2 - Hydrogen generator and fuel cell system having the same - Google Patents

Description

  The present invention relates to a hydrogen generator for a fuel cell system that provides a configuration for maintaining the accuracy of detection of combustion failure of a CO sensor.

Conventionally, this type of CO sensor is provided to detect the CO concentration in an exhaust passage through which the combustion exhaust gas of a burner such as a gas water heater flows, and periodically in order to maintain the accuracy of CO concentration detection. The temperature is raised to perform cleaning (heat cleaning). Since the cleaning timing is performed during combustion when the gas water heater or the like is started, combustion exhaust gas exists around the CO sensor, and substances such as HC in the combustion exhaust gas cause the adhering substance of the CO sensor. Since the removal becomes insufficient, when the stop signal of the combustion operation is detected by the combustion stop detection means, the amount of energization to the CO sensor is increased and the temperature of the CO sensor is increased to the cleaning temperature to perform cleaning. Some sensors are configured so that the CO sensor can be efficiently and reliably cleaned, and the combustion operation and the CO safe operation can be accurately performed over a long period of time (see, for example, Patent Document 1).
Japanese Patent No. 3453441

  However, in the conventional configuration, since the CO sensor is cleaned and the performance is maintained in a state where the combustion operation of the gas water heater or the like is stopped, the performance is maintained depending on the use state of the gas water heater or the like. Since there is an opportunity to stop the combustion operation many times a day, there is a possibility that the cleaning can be sufficiently performed.

  However, the combustion apparatus used for heating the hydrogen generator of the fuel cell system has very few opportunities to stop the combustion operation compared to a gas water heater or the like. This is because the fuel cell system is a power generator, and is often operated continuously, and the combustion operation stop operation may be in a period of one week or one month. In the combustion apparatus of the hydrogen generator, city gas (13A) and LPG are combusted at startup, and off-gas (mixed gas mainly composed of hydrogen) returned from the fuel cell is combusted at the time of power generation. There is a problem in that the amount of substances attached to the sensor increases, the accuracy of CO concentration detection decreases, and a detection failure occurs.

Further, since the water vapor contained in the off gas is large, the amount of water vapor in the combustion exhaust gas is increased, the water is absorbed by the CO sensor, the zero point is shifted, and accurate CO concentration detection is not performed. .
The present invention solves the above-mentioned conventional problems. The CO sensor is cleaned even during the combustion operation of the hydrogen generator heating combustion device, and the combustion failure is detected by the CO sensor without stopping the combustion device for a long period of time. An object of the present invention is to provide a hydrogen generator that can perform with high accuracy.

  In order to solve the conventional problems, a hydrogen generator according to the present invention includes a reforming unit that generates a product gas containing hydrogen by a reforming reaction of a hydrocarbon-based raw material, and a combustion apparatus provided in the reforming unit. And a CO sensor that detects the component of the combustion exhaust gas of the combustion device, and an air supply unit that supplies air around the CO sensor when the cleaning operation of the CO sensor is performed and excludes the combustion exhaust gas. It is a thing.

  As a result, the CO sensor is cleaned without stopping the combustion operation of the hydrogen generator heating combustion device, and the CO sensor deposits and moisture are removed, and the CO sensor heating combustion device is removed over a long period of time. Combustion failure detection can be performed with high accuracy.

  Since the hydrogen generator of the present invention does not stop the combustion operation of the heating combustion device for cleaning the CO sensor, power generation can be continuously performed by the fuel cell system for a long period of time.

According to a first aspect of the present invention, a reforming unit that generates a product gas containing hydrogen by a reforming reaction of a hydrocarbon-based raw material, a combustion device for heating the reforming unit, and component detection of combustion exhaust gas of the combustion device are performed. A CO sensor to be performed and an air supply unit for supplying air around the CO sensor to eliminate combustion exhaust gas when performing the cleaning operation of the CO sensor are provided. Without stopping the combustion operation, it is possible to clean the CO sensor, remove deposits and moisture on the CO sensor, and accurately detect defective combustion in the combustion apparatus for heating by the CO sensor over a long period of time.
In the second aspect of the invention, in particular, the air supply unit supplies air around the CO sensor in order to perform zero correction of the CO sensor after completion of the cleaning operation of the CO sensor, and eliminates the combustion exhaust gas. The remaining combustion exhaust gas remaining around or inside the sensor or components generated by cleaning can be eliminated, and fresh air can be supplied to improve the accuracy of zero point correction.

In the third aspect of the invention, in particular, the air supply unit supplies the air around the CO sensor when performing the cleaning operation of the CO sensor while maintaining the combustion operation of the combustion device. The hydrogen generator can be continuously operated without stopping the combustion device by removing it from the surroundings, performing the cleaning operation with fresh air, and performing the CO sensor cleaning operation even during the combustion operation of the combustion device.
In the fourth invention, in particular, the air supply unit supplies fresh air to the exhaust duct by supplying air into an insertion passage provided for the CO sensor to face the exhaust duct, and removing combustion exhaust gas from the surroundings of the CO sensor. By extruding the combustion exhaust gas in the insertion passage to the exhaust duct, fresh air is filled around the CO sensor, and the cleaning operation of the CO sensor can be performed reliably.

  In the fifth aspect of the invention, in particular, the air supply unit faces the CO sensor in the exhaust duct, supplies air to a sensor cap provided around the CO sensor in order to capture a part of the combustion exhaust gas, and from the inside of the sensor cap. By excluding the combustion exhaust gas, the fresh exhaust air pushes the combustion exhaust gas in the sensor cap into the exhaust duct, so that the CO sensor in the sensor cap is filled with fresh air and the CO sensor cleaning operation is ensured. It can be carried out.

  In the sixth aspect of the invention, in particular, the air supply unit can introduce air with the existing components of the hydrogen generator by supplying air with the air blowing means of the combustion device. Can be prevented.

  Further, since the blowing means of the combustion apparatus is used, there is a surplus in the supply capability of the blowing pressure and the blowing amount, and predetermined air can be introduced into the air supply unit.

  In the seventh aspect of the invention, in particular, since the air supply unit can maintain a constant amount of air by supplying air with an independent supply air blowing unit, the supply air blowing unit can be simplified with a configuration and a control method. Can do.

  In addition, since dedicated air is supplied to the air supply unit, maintenance can be performed without affecting other parts of the hydrogen generator when a failure occurs.

  In the eighth aspect of the invention, in particular, the air supply unit supplies air with the existing components of the fuel cell system by supplying air with the selective oxidation air supply means of the selective oxidation unit of the hydrogen generator. Therefore, a new cost increase can be prevented.

  Further, since the supply of a predetermined amount of air can be maintained at a constant pressure by the selective oxidizing air means, the configuration and the control method can be simplified.

  In the ninth aspect of the invention, in particular, the air supply unit can supply air to the existing components of the fuel cell system by supplying cooling air for the selective oxidation unit via the air valve. New cost increases can be prevented.

  Further, since the supply of the cooling air is controlled by the temperature of the selective oxidation unit, it can be performed with a simplified configuration of opening and closing the air valve.

  In the tenth aspect of the invention, in particular, the air supply unit supplies air with the existing components of the fuel cell system by supplying air with the cathode air supply means for supplying air to the cathode of the fuel cell. Therefore, a new cost increase can be prevented.

  In addition, since a part of the cathode air is sent to the air supply pipe, the air heated by the heat exchanger is supplied, reducing the condensation of water vapor in the combustion exhaust gas by the air, and the CO concentration by the water vapor of the CO sensor. Detection failure can be prevented.

  In the eleventh aspect of the invention, in particular, the air supply unit can supply air with the existing components of the fuel cell system by supplying air with the replacement air supply means of the purge gas of the fuel cell. New cost increase can be prevented.

  Further, the purge gas replacement air supply means is used only for purging the cathode (air electrode) of the fuel cell and is not activated during power generation of the fuel cell, so that it is effectively utilized for supplying air from the air supply pipe. be able to.

  In the twelfth aspect of the invention, in particular, the air supply unit supplies the amount of air around the CO sensor at the time of post-purge of the combustion device so that the high-temperature air exhausted when cooling the hydrogen generator is air. It is possible to improve the life of the CO sensor by cooling with the air supplied from the supply unit and preventing the CO sensor from being placed in a high temperature atmosphere.

    In the thirteenth aspect of the invention, in particular, since the fuel cell system is mounted, the CO sensor is cleaned without stopping the combustion operation of the combustion apparatus for heating the hydrogen generator, and the CO sensor deposits are removed. In addition, even if the fuel cell system is continuously operated over a long period of time, it is possible to accurately detect the combustion failure of the heating combustion device using the CO sensor over a long period of time, and the CO in the exhaust gas of the hydrogen generator When the concentration rises, the fuel cell system can be reliably stopped.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
1 and 2 are configuration diagrams of a hydrogen generator (reforming unit) according to the first embodiment of the present invention.

  In FIG. 1, 1 is a reforming unit that generates hydrogen to be supplied to a fuel cell system using city gas (or LPG or hydrocarbon fuel) as a raw material, and 2 is a treatment in a desulfurization apparatus (not shown). 3 is a raw material gas composed of city gas (or LPG or hydrocarbon fuel) and water vapor, and 3 is a catalyst layer filled with a catalyst mainly composed of nickel or ruthenium. Is subjected to a steam reforming reaction to produce a product gas 4 composed of hydrogen, carbon dioxide and carbon monoxide. Since this generation reaction is an endothermic reaction that occurs at a high temperature of about 700 ° C., the combustion gas is supplied from the combustion device 5 to heat the raw material gas 2 and the catalyst layer 3. A hydrogen generator 6 is configured by the reforming unit (not shown) and the selective oxidation unit (not shown) for removing carbon monoxide from the reforming unit 1 and the product gas 4.

  The combustion device 5 is a distributor of the city gas 7 (or LPG), the off gas 8 (unreacted hydrogen gas) discharged from the fuel cell, or the city gas 7 (or LPG) and the off gas 8 as a fuel gas 9. By ejecting from 10 and supplying air 12 from the periphery of the air ejection part 11, a flame 13 is formed and combustion is performed. A plurality of nozzles 14 for ejecting the fuel gas 9 are provided at the tip of the circular distributor 10 in the circumferential direction of the distributor 10 so that the fuel gas 9 is ejected radially. The air ejection part 11 is provided with a plurality of air ejection holes 15 at substantially right angles on the side surfaces of the air ejection part 11. The air ejection part 11 is configured to form a combustion chamber 16 in a cup shape so as to gradually expand in the direction of the outlet of the flame 13 around the distributor 10 and supply combustion air 12 into the combustion chamber 16. .

  The air ejection holes 15 are arranged in a staggered manner in the vertical direction. The nozzle 14 of the distributor 10 is disposed so as to be substantially opposed to the air ejection hole 17 provided at the lowest stage of the air ejection hole 15 of the air ejection section 11. In addition, a plurality of lower air ejection holes 18 are provided at the bottom of the air ejection section 11 so that a part of the air 12 is ejected in a direction parallel to the axial direction of the distributor 10.

  Reference numeral 19 denotes an air chamber that supplies the air 12, and configures a passage so as to surround the periphery of the air ejection portion 11. A blowing means 21 is provided upstream of the air chamber 19 via a blowing duct 20. The blower means 21 is constituted by a blower that supplies air 12, and a turbo fan, a radial fan, or the like that can generate a high pressure is used as the impeller, which is rotated by a motor. The air blower 21 is controlled by the controller 22.

  Reference numeral 23 denotes a combustion cylinder for avoiding the flame 13 generated by the combustion device 5 from directly touching the catalyst container 24 and further defining the flow path of the combustion gas 25. The combustion gas 25 flows along the periphery of the catalyst container 24 and is discharged to the outside of the reformer 1.

  An insertion passage 26 is provided in the center of the distributor 10 so as to penetrate the distributor 10. The insertion passage 26 is configured to be separated from the distributor 10, and the fuel gas 9 does not enter. An ignition electrode 27 is inserted into the insertion passage 26, and is composed of a heat-resistant Kanthal wire or an esit wire. The periphery of the electrode 27 is covered with an insulating insulator 28 for insulation. The insulator 28 is formed of a ceramic material such as heat-resistant alumina or silica, and the surface thereof is coated with a glaze made of a glass component. The tip of the electrode 27 faces the combustion chamber 16 and is positioned so that spark discharges fly to the top plate 29 of the distributor 10. The operation of the spark discharge of the electrode 27 is controlled by the controller 22.

Reference numeral 30 denotes flame detection means, which constitutes a frame rod with a heat-resistant Kanthal wire or an sweat wire, and detects the presence or absence of the flame 13. The periphery of the flame detection means 30 is covered with an insulating insulator 31 for insulation. The insulator 31 is formed of a ceramic material such as heat-resistant alumina or silica, and a glaze composed of a glass component is applied to the surface thereof. The tip of the flame detection means 30 faces the combustion chamber 16, bends with a curvature, and is positioned so as to face the flame 13 while having a predetermined gap along the inner wall of the air ejection portion 11. . The flame detection means 30 is mounted by extending the tip of the flame detection means 30 from the space 32 provided by expanding a part of the lower part of the combustion cylinder 23 provided at the upper part of the air ejection part 11, on the inner wall of the air ejection part 11. Along the way. In accordance with an instruction from the control unit 22, an alternating current or direct current voltage is applied to the flame detection means 30 to detect an ion current in the flame 13. The data of the flame detection means 30 is determined as a voltage value or a current value. The operation of the flame detection means 30 is controlled by the controller 22.

  33 is an exhaust gas passage provided around the catalyst container 24, and an outlet 34 is provided above the reformer 1 so that the combustion gas 25 flows along the catalyst container 24. It is discharged outside as combustion exhaust gas 35. A cylindrical exhaust duct 36 is connected to the outlet 34. The other of the exhaust duct 36 is connected to a heat exchanger (not shown) to recover the heat of the combustion exhaust gas 35 and prevent a decrease in thermal efficiency.

  Reference numeral 37 denotes a CO sensor provided in the middle of the exhaust duct 36, which takes a part of the combustion exhaust gas 35 into a detection portion facing the exhaust duct 36 and directly measures the component. The CO sensor 37 is controlled by the controller 22.

  Here, the configuration of the CO sensor 37 will be described with reference to FIGS. FIG. 2A shows a circuit diagram of the CO sensor. The CO sensor 37 includes a CO detection element 38, a temperature compensation element 39, and two resistance elements 40 and 41 connected to a bridge circuit. The DC power source E is supplied between the connecting portion between the resistor element 40 and the resistor element 40, and the connecting portion between the temperature compensation element 39 and the resistor element 41, and is heated to a high temperature (about 200 to 400 ° C.) when a current flows. . The CO detection element 38 and the temperature compensation element 39 constitute an alumina carrier on a platinum wire. In the CO detection element, the alumina carrier and an oxidation catalyst (for example, platinum or tin oxide) are sintered and contacted with the surface. The unburned gas is burned by the catalytic action. At this time, since the temperature compensation element 39 is made by sintering a mixture of alumina and glass on an alumina carrier so as not to be in contact combustion, there is a difference in element temperature between the CO detection element 38 and the temperature compensation element 39. Since the resistance value of the platinum wire changes depending on the temperature, the difference between the resistance values of the CO detection element 38 and the temperature compensation element 39 increases as the CO concentration in the combustion exhaust gas increases. As a result, the output value V corresponding to the CO concentration in the combustion exhaust gas 35 is output from the connection portion between the CO detection element 38 and the temperature compensation element 39 and the connection portion between the resistance elements 40 and 41 in the bridge circuit.

  FIG. 2B is a partially cutaway perspective view of the CO sensor. The CO sensor houses a CO detection element 38 and a temperature compensation element 39 in a case 42 made of metal (for example, stainless steel). The CO concentration is detected by receiving a part of the combustion exhaust gas 35 flowing in from the intake 43 of the combustion exhaust gas 35 opened in a part of the exhaust gas. A mesh-shaped lid is attached to the intake port 43 to prevent entry of dust, water droplets and the like. The CO detection element 38 and the temperature compensation element 39 are fixed in the case 42 by providing a pedestal 44 made of a heat-resistant resin material (for example, phenol resin), and supporting the platinum wire there. 38 and the temperature compensation element 39 are arranged so as to be exposed in the air. A partition 45 is erected from the pedestal 44 between the CO detection element 38 and the temperature compensation element 39, and the flow under the same conditions of the combustion exhaust gas 35 flows in parallel around the CO detection element 38 and the temperature compensation element 39. I am doing so. The pedestal 44 and the partition 45 are made of a resin material in order to insulate the platinum wire and improve the accuracy of the shape.

Further, in FIG. 1, the CO sensor 37 instructs to stop the combustion apparatus 5 by stopping the supply of the fuel gas 9 when the CO amount exceeds a predetermined threshold value and it is determined that the combustion state is poor. Yes. When the CO sensor 37 is attached to the exhaust duct 36, a detection portion at the tip thereof is inserted into the exhaust duct 36, and a signal or power connection portion is exposed to the outside to promote heat dissipation and prevent a temperature rise. . The CO sensor 37 is mounted on the exhaust duct 36 by using a packing 46 (for example, heat-resistant Teflon (registered trademark)) between a part of the case 42 of the CO sensor 37 and the outer periphery of the exhaust duct 36. ) And is fixed with a belt (not shown) or the like.

  Reference numeral 47 denotes an air supply unit that communicates with the exhaust duct 36 and introduces fresh air 49 into the exhaust duct 36 from the blower unit 21 through the blower pipe 48. The air supply unit 47 is provided upstream of the CO sensor 37 mounting portion of the exhaust duct 36 (upstream of the flow of the combustion exhaust gas 35. For example, when the combustion exhaust gas 35 is rising, the air supply unit 47 is provided below the CO sensor 37. Will be). An on-off valve 50 is provided in the middle of the blower pipe 48.

  When performing the cleaning operation of the CO sensor 37 by the controller 22, the on-off valve 50 is opened during the combustion operation of the combustion device 5, fresh air 49 is introduced into the exhaust duct 36, and flows into the exhaust duct 36. The combustion exhaust gas 35 is removed with fresh air 49 so that the combustion exhaust gas 35 does not flow around the CO sensor 37. The on-off valve 50 is constituted by an electric valve or a damper. The controller 22 is input to perform the cleaning operation of the CO sensor 37 at regular intervals from the integration time of the continuous combustion time of the combustion device 5 or at regular intervals determined every day. The cleaning of the CO sensor 37 is performed by supplying a direct current power source E between a connection portion between the CO detection element 38 and the resistance element 40 and a connection portion between the temperature compensation element 39 and the resistance element 41, and a high current flows. By increasing the current to a high temperature (450 to 600 ° C.) while heating the state being heated to (about 200 to 400 ° C.), the deposits and moisture on the CO detection element 38 and the temperature compensation element 39 of the CO sensor are removed. Like to do.

51 is a temperature detection part which detects the temperature of the catalyst layer 3, and when operating the hydrogen generator 6,
The control unit 22 controls the ability of the combustion device 5 so that the temperature of the catalyst layer 3 is kept constant by the temperature detection unit 51. The temperature detection unit 51 is composed of a thermistor and a thermocouple. The temperature detector 51 measures the temperature of a part of the outer wall of the catalyst container 24 of the catalyst layer 3 in order to maintain the sealing property of the catalyst layer 3.

  A heat insulating material 52 is provided around the reforming unit 1 in order to reduce heat radiation of the reforming unit 1 and improve thermal efficiency. The heat insulating material 52 is made of a heat resistant material such as glass wool or ceramic fiber.

  About the hydrogen generator 6 comprised as mentioned above, the operation | movement and an effect | action are demonstrated below.

First, when the hydrogen generator 6 is activated, the air blower 21 is operated by the control unit 22 to blow the combustion air 12. The air 12 passes through the blower duct 20 and flows into the air chamber 19, and is supplied to the combustion chamber 16 from the air ejection holes 15 of the air ejection section 11. Here, when the fuel gas 9 of the city gas 7 (or LPG or hydrocarbon fuel) having a different combustion speed or flow rate is ejected from the nozzle 14 of the distributor 10, the fuel gas 9 ejected radially from the distributor 10 is substantially opposed to the fuel gas 9. The air 12 supplied from the lowermost air ejection hole 17 collides and mixes. At this time, spark discharge is performed by the electrode 27 facing the combustion chamber 16 from the insertion passage 26 provided in the center of the distributor 10 so as to penetrate the distributor 10, and the fuel gas 9 is ignited. Although the fuel gas 9 flows in the direction of the opening of the air ejection part 11, since the shape of the air ejection part 11 is cup-shaped as shown in the figure, the flow path cross-sectional area of the fuel gas 9 continuously increases, As a result, the flow velocity of the fuel gas 9 is reduced, and a partially premixed flame 13 is generated and burned at a place where the flow velocity is equal to or lower than the combustion speed of the city gas 7. This combustion heats the catalyst layer 3 of the reformer 1 to promote the steam reforming reaction and generate the product gas 4.

  During power generation of the fuel cell system, off-gas 8 (unreacted hydrogen gas) discharged as the remainder of the product gas 4 supplied from the hydrogen generator 6 to the fuel cell (not shown) is used as the fuel gas 9. The catalyst layer 3 of the reformer 1 is heated to promote the steam reforming reaction.

  At this time, the CO concentration in the combustion exhaust gas 35 is continuously measured by the CO sensor 37, and the state of the flame 13 is evaluated. For example, when the air blower 21 is exhausted or the supply air is blocked, the flame 13 becomes short of air and generates CO, and the CO sensor 37 detects the signal and sends the signal to the controller 22. The control unit 22 determines that the combustion state of the combustion device 5 is defective when the signal exceeds a predetermined value (for example, a threshold signal corresponding to the maximum amount of CO emission defined by JIS or the like), and the combustion device 5 is instructed to stop. In addition, the control unit 22 instructs the hydrogen generator 6 and the fuel cell system to perform a stop operation. Further, even if the flame 13 becomes excessive in air due to a decrease in the supply amount due to a decrease in temperature or a supply failure of the fuel gas 9, the signal of the CO sensor 37 is similarly evaluated to determine the combustion state. Like to do. The flame detection means 30 measures the ionic current of the flame 13 and determines whether a predetermined data signal is obtained by the control unit 22 as a voltage value or a current value. If there is an abnormality, the combustion apparatus 5 is stopped. We are trying to ensure safety.

  While the combustion operation of the combustion device 5 continues, the controller 22 opens the on-off valve 50 when a predetermined integration time or time is reached, introduces fresh air 49 into the exhaust duct 36, and circulates in the exhaust duct 36. The combustion exhaust gas 35 is removed with fresh air 49 so that the combustion exhaust gas 35 does not flow around the CO sensor 37. In this fresh air 49, a DC power source E is supplied between the connection part of the CO detection element 38 and the resistance element 40 and the connection part of the temperature compensation element 39 and the resistance element 41, and a current flows. Is increased to a high temperature (450 to 600 ° C.) to remove the deposits and moisture on the CO detection element 38 and the temperature compensation element 39 of the CO sensor, and the CO sensor is cleaned by the combustion operation of the combustion device 5. The detection performance of the CO sensor 37 is maintained for a long time.

  As described above, in the present embodiment, the CO sensor 37 is cleaned without stopping the combustion operation of the heating combustion device 5 of the hydrogen generator 6, and the deposits and moisture on the CO sensor 37 are removed. Thus, it is possible to accurately detect the combustion failure of the heating combustion device 5 by the CO sensor 37 over a long period of time.

  Further, since it is not necessary to stop the combustion device 5 for the cleaning operation of the CO sensor 37, the hydrogen generator 6 can be continuously operated, and the production of hydrogen can be maintained for a long time.

  In addition, since fresh air 49 is distributed from the air 12 when performing the cleaning operation, the fresh air 49 is increased by fully utilizing the capacity of the blower, and the combustion exhaust gas 35 is excluded from the surroundings of the CO sensor 37, thereby improving the impurities. Cleaning can be surely performed by oxygen in the fresh air 49 that is not contained.

  In addition, since the opening / closing valve 50 is provided in the middle of the blower pipe 48 and the blower pipe 48 is closed except for the cleaning operation, the combustion exhaust gas 35 during the operation of the combustion device 5 is prevented from flowing back to the blower pipe 48. It is possible to prevent the 35 CO concentration detection accuracy from being lowered.

  In addition, since the CO sensor 37 employs a contact combustion type, the hydrogen component in the combustion exhaust gas 35 is also sensitive, so the combustion state of the off gas 8 changes and a large amount of hydrogen in the fuel gas 9 is present. Even if it slips, it determines with the combustion failure of the combustion apparatus 5, and safety | security can be ensured.

  Further, since the flame detection means 30 determines the presence or absence of the flame 13, misfire due to a sudden change in the combustion state can be evaluated, and the time delay of the measurement of the CO sensor 37 is complemented to cope with a sudden change in the combustion state. be able to.

  In addition, a CO sensor 37 that detects a component of the flue gas 35 of the combustion device 5 and a control unit 22 that stops the combustion device 5 when the combustion state of the combustion device 5 can be determined to be defective from the signal of the CO sensor 37 are provided. Therefore, when the flame 13 becomes defective due to fluctuations in the combustion air 12 or the fuel gas 9, the CO sensor 37 can directly determine the components of the combustion exhaust gas 35 so that the poor combustion state can be determined. The combustion apparatus 5 can be stopped with high accuracy, and the safety of the hydrogen generator 6 (fuel cell system) can be ensured.

  Further, since the distributor 10 for injecting the fuel gas 9 in the peripheral direction and the air injection portion 11 for injecting the air 12 from the periphery toward the center so as to surround the distributor 10 are provided, the mixing of the fuel gas 9 and the air 12 is performed. The flame 13 can be shortened and the hydrogen generator 6 can be downsized.

  Further, since the nozzle 14 and the lowermost air ejection hole 17 are arranged substantially opposite to promote the mixing of the fuel gas 9 and the air 12, in this part, the hydrogen that is easy to burn and the combustion speed is high is the air. Mixing sufficiently, the flame 13 always maintains a stable state, and the characteristics of the combustion exhaust gas 35 can be improved.

  Further, since the air 12 is ejected from the position intersecting the fuel gas 9 from below through the lower air ejection hole 18, the mixing of the fuel gas 9 and the air 12 can be further improved. This air 12 not only improves the gas mixing, but also maintains the flame 13 even when the flow rate of the air 12 is relatively excessively supplied with respect to the flow rate of the combustion gas 9, thereby stabilizing the combustion. It has a great effect on conversion.

  Further, since the city gas 7 (or LPG or hydrocarbon fuel) or the different offgas 8 fuel returning from the fuel cell can be ejected from the nozzle 14 of the distributor 10, the configuration is simplified and the cost can be reduced.

  Further, since the city gas 7 (or LPG or hydrocarbon fuel) or the off gas 8 is always ejected from the distributor 10, the distributor 10 is cooled and is not overheated by the flame 13, and can be used for a long period of time.

The signal is detected by the CO sensor 37 and sent to the control unit 22, and the control unit 22 sets a predetermined value (for example, a threshold value based on a signal corresponding to the maximum discharge amount of CO defined by JIS or the like). When exceeding, the combustion state of the combustion device 5 is determined to be defective and an instruction to stop the combustion device 5 is issued. However, the control unit 22 sets the signal of the CO sensor 37 to a value lower than a predetermined value, and the blowing unit 21. (For example, even if the CO value is lower than a predetermined value, the air 12 is increased to reduce the CO concentration, and this operation is repeated each time the CO concentration increases) If the CO sensor 37 exceeds the predetermined value at the time, the combustion device 5 may be stopped.
The air supply unit 47 supplies air around the CO sensor 37 to eliminate the combustion exhaust gas 35 in order to perform zero point correction of the CO sensor 37 after the cleaning operation of the CO sensor 37 is completed.

  About the hydrogen generator 6 comprised as mentioned above, the operation | movement and an effect | action are demonstrated below.

  When the zero point correction operation of the CO sensor 37 is performed during the combustion operation of the combustion device 5, the opening / closing valve 50 provided in the middle of the blower pipe 48 is opened, and a part of the air 12 is blown from the blower duct 20. Is supplied as fresh air 49 from upstream of the CO sensor 37 mounting position in the exhaust duct 36, and the flow of the combustion exhaust gas 35 is changed by the fresh air 49 upstream of the CO sensor 37, and combustion is performed from around the CO sensor 37. The exhaust gas 35 is removed to carry out. In the controller 22, the output value of the CO sensor 37 in the fresh air 49 is reset as a zero point.

  As described above, in the present embodiment, the fresh air 49 fills the periphery of the CO sensor 37 before the combustion exhaust gas 35 reaches the CO sensor 37. Therefore, the zero point based on the fresh air 49 is accurately set. The CO sensor 37 can be prevented from being deteriorated against long-term continuous use of the CO sensor 37, and the accuracy of CO concentration detection can be maintained over a long period of time.

  In addition, since fresh air 49 is supplied around the CO sensor 37 after the cleaning operation is completed, the remaining flue gas 35 remaining around or inside the CO sensor 37 or components generated by the cleaning are eliminated, and zero point correction is performed. Accuracy can be improved.

  Moreover, since the air supply part 47 is a simple structure which connects the ventilation duct 48 to the exhaust duct 36, the cost increase can also be suppressed low.

  Note that when the zero point correction of the CO sensor 37 is performed, if the variation of the initial zero point output value and the zero point output value of the zero point correction periodically performed thereafter are compared, the deterioration of the CO sensor 37 will occur. The situation can be determined, and it is possible to instruct the replacement timing of the CO sensor 37 when the variation exceeds a predetermined value.

  Further, the air supply unit 47 supplies fresh air 49 around the CO sensor 37 when performing the cleaning operation of the CO sensor 37 while maintaining the combustion operation of the combustion device 5.

  About the hydrogen generator 6 comprised as mentioned above, the operation | movement and an effect | action are demonstrated below. When the cleaning operation of the CO sensor 37 is performed during the combustion operation of the combustion device 5, the opening / closing valve 50 provided in the middle of the blower pipe 48 is opened, and a part of the air 12 is introduced into the blower pipe 48 from the blower duct 20. Then, fresh air 49 is supplied from upstream of the CO sensor 37 mounting position in the exhaust duct 36, the flow of the combustion exhaust gas 35 is changed by the fresh air 49 upstream of the CO sensor 37, and the combustion exhaust gas 35 is discharged from around the CO sensor 37. It is done by removing. Thereby, the cleaning operation of the CO sensor 37 is performed without stopping the combustion device 5.

  As described above, in the present embodiment, the combustion exhaust gas 35 is excluded from the surroundings of the CO sensor 37, the cleaning operation is performed with the fresh air 49, and the cleaning operation of the CO sensor 37 is performed even during the combustion operation of the combustion device 5. Thus, the hydrogen generator 6 can be continuously operated without stopping the combustion device 5.

Further, since it is not necessary to stop the combustion device 5 for the cleaning operation of the CO sensor 37, the hydrogen generator 6 can be continuously operated, and the production of hydrogen can be maintained for a long time.
Further, in FIG. 1, the air supply unit 47 supplies fresh air 49 by the air blowing means 21 of the combustion device 5. The air supply unit 47 branches from the middle of the blower duct 20 that supplies the combustion air 12 to the combustion device 5 using the blower 21 via the blower pipe 48 and is connected to the exhaust duct 36.
About the hydrogen generator 6 comprised as mentioned above, the operation | movement and an effect | action are demonstrated below.

When performing the cleaning operation of the CO sensor during the combustion operation of the combustion device 5, the opening / closing valve 50 provided in the middle of the blower pipe 48 is opened, a part of the air 12 is supplied from the blower duct 20 to the blower pipe 48, Fresh air 49 is introduced into the exhaust duct 36 through the blower pipe 48, and the combustion exhaust gas 35 is excluded from the surroundings of the CO sensor 37. At this time, the air blowing means 21 is controlled by the control unit 22 so as to send fresh air 49 in addition to the air 12 necessary for the combustion operation of the combustion device 5.
As described above, in the present embodiment, the air supply unit 47 supplies the fresh air 49 by the blower unit 21 of the combustion device 5, so that the blower unit 21 that is an existing component of the combustion device 5 is used. Since the fresh air 49 can be supplied, the configuration is simple and a new cost increase can be prevented.

    Further, since the blowing means 21 of the combustion device 5 is used, there is a surplus in the ability of blowing pressure and blowing amount, and the predetermined fresh air 49 can be introduced into the air supply unit 47.

(Embodiment 2)
FIG. 3 is a partial cross-sectional view showing the hydrogen generator 6 in the second embodiment of the present invention.

  In FIG. 3, the air supply unit 47 supplies fresh air 49 into an insertion passage 53 provided to allow the CO sensor 37 to face the exhaust duct 36, and excludes the combustion exhaust gas 35 from the surroundings of the CO sensor 37. ing. The CO sensor 37 is attached so that the CO sensor 37 is fixed to the attachment portion 54 of the insertion passage 53 with a screw or the like via a packing 55 (for example, a resin such as heat-resistant Teflon (registered trademark)). I have to. The insertion passage 53 is provided to improve the assemblability when the CO sensor 37 is mounted.

  About the hydrogen generator 6 comprised as mentioned above, the operation | movement and an effect | action are demonstrated below.

  When the cleaning operation of the CO sensor 37 is performed during the combustion operation of the combustion device 5, the opening / closing valve 50 provided in the middle of the blower pipe 48 is opened, and a part of the air 12 is supplied from the blower duct 20 to the blower pipe 48. The fresh air 49 is supplied into the insertion passage 53 provided in the exhaust duct 36 through the blower pipe 48 to remove the high-temperature combustion exhaust gas 35 that enters the insertion passage 53, thereby the CO sensor 37 in the insertion passage 53. The surroundings are filled with fresh air and the cleaning operation is performed.

As described above, in this embodiment, the fresh air 49 pushes the combustion exhaust gas 35 in the insertion passage 53 to the exhaust duct 36, so that the fresh air 49 is filled around the CO sensor 37, and the CO sensor 37 Since the cleaning operation is performed reliably, the combustion exhaust gas 35 entering the insertion passage 53 can be eliminated, so that the deterioration of the CO sensor 37 can be prevented and the accuracy of CO concentration detection can be maintained over a long period of time.

(Embodiment 3)
FIG. 4 is a partial cross-sectional view showing the hydrogen generator 6 in the third embodiment of the present invention.

  In FIG. 4, the air supply unit 47 faces the CO sensor 37 to the exhaust duct 36, supplies fresh air 49 to a sensor cap 56 provided around the CO sensor 37 in order to capture a part of the combustion exhaust gas 35, The cleaning operation of the CO sensor 37 is performed. The sensor cap 56 is provided to suppress the flow rate when a part of the combustion exhaust gas 35 is taken into the CO sensor 37 and form a uniform flow. The sensor cap 56 is fixed to the insertion passage 53 with the CO sensor 37 through the packing 55 by close tightening.

  About the hydrogen generator 6 comprised as mentioned above, the operation | movement and an effect | action are demonstrated below.

  When the cleaning operation of the CO sensor 37 is performed during the combustion operation of the combustion device 5, the opening / closing valve 50 provided in the middle of the blower pipe 48 is opened, and a part of the air 12 is supplied from the blower duct 20 to the blower pipe 48. The fresh air 49 is supplied into the sensor cap 56 provided in the insertion passage 53 through the blower pipe 48, and the combustion exhaust gas 35 entering the sensor cap 56 is pushed out into the exhaust duct, so that the inside of the sensor cap 56 The cleaning operation is surely performed by filling fresh air 49 around the CO sensor 37.

  As described above, in the present embodiment, since the fresh air 49 is supplied into the sensor cap 56, the fresh air 49 replaces the surroundings of the CO sensor 37 with the fresh air 49 in a short time, and the CO sensor 37 is surely received. The cleaning operation can be performed.

  In addition, since the combustion exhaust gas 35 remaining in the sensor cap 56 is periodically replaced with fresh air 49, the surroundings of the CO sensor 37 can be periodically cleaned to reduce variation in CO concentration detection.

(Embodiment 4)
FIG. 5 is a sectional view showing a hydrogen generator 6 in the fourth embodiment of the present invention.

  In FIG. 5, the air supply unit 47 supplies fresh air 49 by an independent supply air blowing means 57. The supply air blowing means 57 is constituted by a blower that introduces fresh air 49, and a turbo fan or a radial fan that can generate a high pressure is used as an impeller, which is rotated by a motor. The controller 22 controls the supply air blowing means 57.

  About the hydrogen generator 6 comprised as mentioned above, the operation | movement and an effect | action are demonstrated below.

  When the CO sensor cleaning operation is performed during the combustion operation of the combustion device 5, the fresh air 49 is supplied from the air supply unit 47 into the exhaust duct 36 through the air supply pipe 47 by the supply air blowing means 57. The controller 22 keeps the supply air supply means 57 in a constant state by simple control such as turning on and off.

  As described above, in the present embodiment, the air supply unit 47 can maintain the fresh air 49 with a constant amount of air by supplying the fresh air 49 by the independent supply air blowing means 57, so that the supply air The air blowing means 57 can be simplified by the configuration and the control method.

  In addition, since fresh air 49 is supplied to the air supply unit 47 alone, replacement maintenance or the like can be performed without affecting other parts of the hydrogen generator 6 when a failure occurs.

  Although the supply air supply means 57 is constituted by a blower, it is also possible to use a pump or a booster capable of producing a high pressure.

  When the cleaning operation is stopped during the combustion operation of the combustion device 5, an opening / closing valve 50 is provided in the middle of the blower pipe 48 so that the combustion exhaust gas 35 does not flow backward in the blower pipe 48, and the blower pipe 48 is closed. It is also possible to do.

When the cleaning operation is stopped during the combustion operation of the combustion device 5, the blower pipe 48 is used.
In order to prevent the combustion exhaust gas 35 from flowing backward, it is possible to introduce an amount of fresh air 49 from the blower pipe 48 into the exhaust duct 36 so as not to affect the CO detection of the CO sensor 37.

(Embodiment 5)
FIG. 6 is a cross-sectional view showing a hydrogen generator 6 according to the fifth embodiment of the present invention.

In FIG. 6, the air supply unit 47 supplies fresh air 49 from a part of the selective oxidation air 61 by the selective oxidation air supply means 59 of the selective oxidation unit 58 of the hydrogen generator 6. The hydrogen generator 6 is constituted by a reforming unit 60 and a selective oxidation unit 58 for removing carbon monoxide from the reforming unit 1 and the product gas 4. The selective oxidizing air supply means 59 supplies the selective oxidizing air 61 to the selective oxidizing unit 58 to remove CO (oxidizes carbon monoxide to reduce its concentration) in the product gas 4. .
The selective oxidation air 58 and the selective oxidation air supply means 59 communicate with each other through a selective oxidation air supply pipe 62.
A selective oxidation air valve 63 is provided in the middle of the selective oxidation air supply pipe 62. The selective oxidation air valve 63 is constituted by an electric valve or a damper. A blowing pipe 48 is branched from a selective oxidizing air supply pipe 62 in the middle of the selective oxidizing air valve 63 and the selective oxidizing air supply means 59, and is connected to the air supply unit 47. With this configuration, fresh air 49 is sent from the selective oxidation supply means 59 to the air supply unit 47. The selective oxidation supply means 59 is configured by a pump, a booster, a blower or the like that can take supply pressure to supply the selective oxidation air 61.

  About the hydrogen generator 6 comprised as mentioned above, the operation | movement and an effect | action are demonstrated below.

  When the cleaning operation of the CO sensor 37 is performed during the combustion operation of the combustion device 5, the opening / closing valve 50 provided in the middle of the blower pipe 48 is opened by the instruction of the control unit 22 and the selective oxidation air supply means 59 performs the selective oxidation. Fresh air 49 is introduced from the air supply unit 47 into the exhaust duct 36 through the air supply pipe 62 and the blower pipe 48 to eliminate the combustion exhaust gas 35 around the CO sensor 37. At this time, the selective oxidation air supply means 59 controls the selective oxidation air supply means 59 so that the fresh air 49 is sent in addition to the selective oxidation air 61 by the control unit 22.

  When the cleaning operation of the CO sensor 37 is stopped during the combustion operation of the combustion device 5, the selective oxidation air valve 63 is opened and the selective oxidation air 61 is supplied to the selective oxidation unit 58. At this time, the on-off valve 50 provided in the middle of the blower pipe 48 is closed so that the combustion exhaust gas 35 does not flow backward to the blower pipe 48. Thereafter, the selective oxidation air supply means 59 supplies the selective oxidation air 61 while power generation is performed by the fuel cell system.

  As described above, in the present embodiment, the air supply unit 47 introduces the fresh air 49 by the selective oxidation air supply means 59 of the selective oxidation unit 58 of the hydrogen generator 6, so that the existing fuel cell system is provided. Since fresh air 49 can be supplied with these components, it is possible to prevent a new cost increase.

In addition, since the selective air supply means 59 can supply and maintain the fresh air 49 having a predetermined amount of air at a constant pressure, the configuration and the control method can be simplified.
(Embodiment 6)
FIG. 7 shows a system diagram of the hydrogen generator in the sixth embodiment of the present invention.

In FIG. 7, the air supply unit 47 supplies fresh air 49 from a part of the cooling air 65 of the selective oxidation unit 58. The supply air blowing means 66 supplies the cooling air 65 of the selective oxidation unit 58 via the air valve 64. The air valve 64 is configured by an electric valve or a damper. A fresh air supply pipe 67 is branched in the middle of a blow pipe 48 that communicates the supply air blowing means 66 and the air supply section 47. An opening / closing valve 50 is provided in the air supply pipe 48 between the point where the fresh air supply pipe 67 is branched and the air supply section 47. The other side of the fresh air supply pipe 67 communicates with a cooling air passage 68 provided around the selective oxidation unit 58. An air valve 64 is provided in the fresh air supply pipe 67 between the cooling air passage 68 and the blower pipe 48. Further, in order to keep the temperature of the selective oxidation unit 58 in a predetermined temperature range, the control unit 22 controls the supply of the cooling air 65 by opening and closing the air valve 64. The supply air blowing means 66 is composed of a pump, a booster, a blower or the like that can take supply pressure to supply the cooling air 65. Reference numeral 69 denotes a temperature detection unit of the selective oxidation unit 58, which is a thermocouple or a thermistor.

  About the hydrogen generator 6 comprised as mentioned above, the operation | movement and an effect | action are demonstrated below.

  When the cleaning operation of the CO sensor 37 is performed during the combustion operation of the combustion device 5, the open / close valve 50 is opened according to an instruction from the control unit 22, and the fresh air 49 is supplied by the supply air blowing means 66 through the blowing pipe 48. Is introduced into the exhaust duct 36 from the air supply unit 47 to eliminate the combustion exhaust gas 35 from the periphery of the CO sensor 37.

  When the combustion apparatus 5 is in a combustion operation, the control unit 22 measures the temperature of the selective oxidation unit 58 by the temperature detection unit 69, and when the temperature exceeds a predetermined range, the air valve 64 is opened to cool the unit. The working air 65 is supplied to the cooling air passage 68. Thereafter, the cooling air 65 is supplied by the supply air blowing means 66 while power generation is performed by the fuel cell system. Further, when the temperature of the selective oxidation unit 58 decreases, the cooling air 65 repeatedly closes the air valve 64 and opens and closes the air valve 65 or turns on and off the supply air blowing means 66 to turn on and off the selective oxidation unit. The temperature of 58 is kept within a certain range.

  Even when the air valve 64 is closed, the fresh air 49 is supplied to the air supply unit 47 via the fresh air supply pipe 67 by the supply air blowing means 66.

  As described above, in the present embodiment, the air supply unit 47 supplies the fresh air 49 by the supply air blowing means 66 that supplies the cooling air 65 of the selective oxidation unit 58, thereby providing a fuel cell. Since existing components of the system can be used and shared, new cost increases can be prevented.

Further, since the supply air blowing means 66 only supplies the cooling air 67 of the selective oxidation unit 58 during the operation of the combustion apparatus 5, it can be controlled simply to supply a constant amount of air.
When the fresh air 49 is supplied to the air supply part 47, it can carry out easily.

Further, the supply of the cooling air 65 is controlled by the temperature of the selective oxidizer 58, so that it can be performed with a simplified configuration in which the air valve 64 is opened and closed or the supply air blowing means 66 is turned on and off.
(Embodiment 7)
FIG. 8 shows a system diagram of the hydrogen generator in the seventh embodiment of the present invention.

In FIG. 8, the air supply unit 47 supplies fresh air 49 by cathode air supply means 72 that supplies cathode air 71 to the cathode 70 of the fuel cell. The cathode air supply means 72 is constituted by a blower, and uses a turbo fan, a radial fan, or the like that can generate a high pressure as an impeller, and rotates the motor with a motor. The control unit 22 controls the cathode air supply means 72. The cathode air supply means 72 communicates with an inlet 74 of the cathode 71 through a cathode air supply pipe 73. The blower pipe 48 is branched from the middle of the cathode air supply pipe 73, a part of the cathode air 71 is introduced as fresh air 49 into the exhaust duct 36 from the air supply section 47, and the combustion exhaust gas 35 around the CO sensor 37 is introduced. Is eliminated. An air on / off valve 75 is provided except that an air on / off valve 75 is provided in the middle of the cathode air supply pipe 73 between the branched portion of the blower pipe 48 and the inlet 74 of the cathode 70 and the cathode 70 requires the cathode air 71. Is closed to keep the cathode 70 sealed. When the on-off valve 50 is provided between the point where the air supply pipe 47 branches from the cathode air supply pipe 73 and the air supply section 47 and the combustion device 5 performs the combustion operation and the cleaning operation of the CO sensor 37 is not performed, the on-off valve 50 is closed so that the cathode air 71 does not flow out of the air supply unit 47.

  About the hydrogen generator 6 comprised as mentioned above, the operation | movement and an effect | action are demonstrated below.

  When the cleaning operation of the CO sensor 37 is performed during the combustion operation of the combustion device 5, the on-off valve 50 is opened by the instruction of the control unit 22, and fresh air is supplied via the blower pipe 48 by the cathode air supply means 72. 49 is supplied from the air supply unit 47 into the exhaust duct 36 to eliminate the combustion exhaust gas 35 around the CO sensor 37. In the control unit 22, when supplying the cathode air 71 to the cathode 70, the air opening / closing valve 75 is opened. When the cathode air 71 is not necessary for the cathode 70, the air on-off valve 75 is closed. When the combustion device 5 is operating, the cathode air 71 is continuously supplied by the cathode air supply means 72. When the cleaning operation of the CO sensor 37 is not performed, the opening / closing valve 50 of the blower pipe 48 is closed. Yes.

  As described above, in the present embodiment, the air supply unit 47 can supply the fresh air 49 by the cathode air supply means 72 which is an existing component of the fuel cell system, and thus the configuration is simple. This can prevent a new cost increase.

Further, since a part of the cathode air 71 is sent to the air supply pipe 73, the fresh air 49 heated by a heat exchanger (not shown) is supplied, and the dew condensation of the water vapor in the combustion exhaust gas 35 by the fresh air 49 is caused. The CO concentration detection failure due to the water vapor of the CO sensor 37 can be prevented.
(Embodiment 8)
FIG. 9 shows a system diagram of the hydrogen generator in the eighth embodiment of the present invention.

In FIG. 9, the air supply unit 47 supplies fresh air 49 by the replacement air supply means 77 of the purge gas 76 of the fuel cell. The replacement air supply means 77 is configured by a pump, a booster, a blower, or the like that can take supply pressure to push the purge gas 76 with the replacement air 78. The replacement air supply means 77 communicates with the inlet 74 of the cathode 70 through a replacement air supply pipe 79 branched from the middle of the cathode air supply pipe 73. Thereby, the purge gas 76 in the cathode 70 is pushed out by the replacement air 78 supplied to the replacement air supply means 77 so that the cathode 70 is filled with the replacement air 78. A replacement air valve 80 is provided in the middle of the replacement air supply pipe 79 and is opened during the discharge process of the purge gas 76 of the cathode 70 before or after the power generation of the fuel cell system. At other times, the replacement air valve 80 is closed. A blower pipe 48 is branched from a replacement air supply pipe 79 between the replacement air valve 80 and the replacement air supply means 77, and a part of the replacement air 78 is supplied as fresh air 49 from the air supply unit 47 into the exhaust duct 36. Thus, the combustion exhaust gas 35 is excluded from the surroundings of the CO sensor 37. An on-off valve 50 is provided between a point where the blower pipe 48 branches from the replacement air supply pipe 79 and the air supply unit 47. The on-off valve 50 and the replacement air valve 80 are constituted by electric valves and dampers.

  About the hydrogen generator 6 comprised as mentioned above, the operation | movement and an effect | action are demonstrated below.

  When the cleaning operation of the CO sensor 37 is performed during the combustion operation of the combustion device 5, the opening / closing valve 50 of the blower pipe 47 is opened by the instruction of the control unit 22, and the replacement air supply means 77 passes the blower pipe 47 through the blower pipe 47. The fresh air 49 is introduced into the exhaust duct 36 from the air supply unit 47 to exclude the combustion exhaust gas 35 from the periphery of the CO sensor 37.

  In the control unit 22, the replacement air valve 80 is opened and the replacement air 78 is supplied to the cathode 70 during the discharge process of the purge gas 76 of the cathode 70 before or after the power generation of the fuel cell system. At other times, the replacement air valve 80 is closed so that the CO sensor 37 is not simultaneously cleaned.

  As described above, in the present embodiment, the air supply unit 47 supplies the supply air 49 by the replacement air supply means 77 of the purge gas 76 of the cathode 70, so that the replacement is an existing component of the fuel cell system. By sharing the air supply means 77, new cost increases can be prevented.

  Further, the replacement air supply means 78 is used only for discharging the purge gas 76 of the cathode 70 of the fuel cell and is not operated during the power generation of the fuel cell, so that the fresh air 49 is supplied from the air supply unit 47. Therefore, it can be used effectively.

(Embodiment 9)
FIG. 10 is a sectional view showing the hydrogen generator 6 in the ninth embodiment of the present invention.
In FIG. 10, the air supply unit 47 supplies hot air 49 around the CO sensor 37 at the time of post-purging of the combustion device 5, so that the high-temperature exhaust air exhausted when the hydrogen generator 6 is cooled. 81 is cooled by fresh air 49 supplied from the air supply unit 47. The controller 22 supplies the fresh air 49 until the temperature detection unit 52 of the reforming unit 1 decreases to a predetermined temperature.
About the hydrogen generator 6 comprised as mentioned above, the operation | movement and an effect | action are demonstrated below.

The controller 22 stops the combustion device 5 and opens the on-off valve 50 provided in the middle of the blower pipe 48 before starting the post-purge operation of the hydrogen generator 6 to distribute a part of the air 12 from the blower duct 20. The fresh air 49 is supplied to the exhaust duct 36. At this time, the temperature detection unit 52 of the catalyst layer 3 provided in the reformer 1 monitors the temperature of the catalyst layer 3 during the post purge, and the catalyst layer 3 has a predetermined temperature (when the hydrogen generator 6 is stopped) If the catalyst layer is left at a high temperature, carbon is deposited on the catalyst layer 3 and the catalyst deteriorates. Therefore, the post-purge operation is continued until it is necessary to rapidly cool to about 100 to 150 ° C. The hot exhaust air 81 discharged to 36 is diluted with fresh air 49 introduced from the air introduction portion 47 and cooled to prevent the temperature of the CO sensor 37 from rising.
As described above, in the present embodiment, the air introduction unit 47 cools the hydrogen generator 6 by supplying the fresh air 49 around the CO sensor 37 during the post purge of the combustion device 5. It is possible to cool the hot exhaust air 81 exhausted to a high temperature and prevent the CO sensor 37 from being placed in a high temperature atmosphere to prevent the deterioration of the CO sensor 37 and maintain the accuracy of CO concentration detection over a long period of time. it can.
In addition, it is possible to easily control the timing of introducing the cooling air 49 by applying the existing temperature detection unit 52, and it is possible to prevent the cost increase factor of adding a new temperature detection component.
(Embodiment 10)
FIG. 11 is an overall configuration diagram showing a fuel cell system according to a tenth embodiment of the present invention.
In FIG. 11, in order to perform the cleaning operation of the CO sensor 37 by the air supply unit 47, the hydrogen generator 6 for introducing fresh air 49 around the CO sensor 37 is mounted on the fuel cell system 82. The fuel cell system 82 includes a polymer electrolyte fuel cell 83, a hot water supply device (not shown), and the like. Any of the hydrogen generators shown in Embodiments 1 to 5 can be used.

  About the hydrogen generator 6 comprised as mentioned above, the operation | movement and an effect | action are demonstrated below.

When the cleaning operation of the CO sensor 37 is performed during the combustion operation of the combustion device 5, the opening / closing valve 50 of the blower pipe 47 is opened by the instruction of the control unit 22, and the fresh air 49 is discharged from the air introduction unit 47 to the exhaust duct 36. The combustion exhaust gas 35 is removed from the surroundings of the CO sensor 37 and the cleaning operation of the CO sensor 37 is performed reliably.
As described above, in the present embodiment, the CO sensor 37 is cleaned without stopping the combustion operation of the heating combustion device 5 of the hydrogen generator 6 by being mounted on the fuel cell system 82. Because it operates and removes the deposits and moisture from the CO sensor 37, even if the fuel cell system is continuously operated over a long period of time, it can accurately detect the combustion failure of the heating combustion device using the CO sensor over a long period of time. When the CO concentration in the combustion exhaust gas of the hydrogen generator 6 increases, the fuel cell system can be reliably stopped.

  As described above, the hydrogen generator according to the present invention introduces fresh air from the air supply unit around the CO sensor of the combustion apparatus for heating, and performs the cleaning operation of the CO sensor during the combustion operation of the combustion apparatus. Since combustion failure detection can be accurately performed over a period of time, it can be applied to a heat source of a water heater or a heater.

Configuration diagram of a hydrogen generator in Embodiment 1 of the present invention (A) Circuit diagram of the CO sensor in the hydrogen generator of the present invention (b) Same as above, partially cut away perspective view of the CO sensor Partial sectional view of a hydrogen generator in Embodiment 2 of the present invention Configuration diagram of a hydrogen generator in Embodiment 3 of the present invention Configuration diagram of a hydrogen generator in Embodiment 4 of the present invention Configuration diagram of a hydrogen generator in Embodiment 5 of the present invention System diagram of hydrogen generator in Embodiment 6 of the present invention System diagram of hydrogen generator in Embodiment 7 of the present invention System diagram of hydrogen generator in Embodiment 8 of the present invention System diagram of hydrogen generator in Embodiment 9 of the present invention Configuration diagram of fuel cell system in Embodiment 10 of the present invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Reformation part 4 Product gas 5 Combustion apparatus 6 Hydrogen generator 35 Combustion exhaust gas 37 CO sensor 47 Air supply part 48 Blower pipe 49 Fresh air 50 On-off valve

Claims (13)

A reforming unit that generates a product gas containing hydrogen by a reforming reaction of a hydrocarbon-based raw material, a combustion device provided in the reforming unit, a CO sensor that detects a component of combustion exhaust gas of the combustion device, and A hydrogen generator provided with an air supply unit for supplying air around the CO sensor and eliminating combustion exhaust gas when performing a cleaning operation of the CO sensor. 2. The hydrogen generator according to claim 1, wherein the air supply unit supplies air around the CO sensor in order to correct the zero point of the CO sensor after the completion of the cleaning operation of the CO sensor to exclude combustion exhaust gas. The hydrogen generator according to claim 1 or 2, wherein the air supply unit supplies air around the CO sensor when performing the cleaning operation of the CO sensor while maintaining the combustion operation of the combustion device. The hydrogen generator according to claim 1 or 3, wherein the air supply unit supplies air into an insertion passage provided to allow the CO sensor to face the exhaust duct and excludes combustion exhaust gas from the surroundings of the CO sensor. The air supply unit faces a CO sensor in an exhaust duct, supplies air to a sensor cap provided around the CO sensor in order to capture a part of the combustion exhaust gas, and excludes the combustion exhaust gas from the sensor cap. The hydrogen generator of any one of -4. The hydrogen generator according to any one of claims 1 to 5, wherein the air supply unit supplies air by a blower of the combustion device. The hydrogen generator according to claim 1, wherein the air supply unit supplies air by an independent supply air blowing unit. The hydrogen generator according to any one of claims 1 to 7, wherein the air supply unit supplies air by a selective oxidation air supply unit of a selective oxidation unit of the hydrogen generator. The hydrogen generator according to claim 1, wherein the air supply unit supplies cooling air for the selective oxidation unit via an air valve. The hydrogen generator according to any one of claims 1 to 9, wherein the air supply unit supplies air by cathode air supply means for supplying air to a cathode of the fuel cell. The hydrogen generator according to any one of claims 1 to 10, wherein the air supply unit supplies air by means of a replacement air supply means for purge gas of the fuel cell. The hydrogen generator according to any one of claims 1 to 11, wherein the air supply unit supplies an amount of air around the CO sensor during post-purge of the combustion device. A fuel cell system comprising the hydrogen generator according to any one of claims 1 to 12.

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