JP2005005099A - Fuel cell system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell system in which reduction of combustion efficiency is suppressed. <P>SOLUTION: This system is provided with a fuel cell 3 to generate electricity using fuel gas and oxidizer gas, a mixing part 4 to mix the fuel exhaust gas from the fuel cell 3 and oxygen-containing gas, and a combustor 7 to combustion-treat the mixed gas generated in the mixing part 4 using a combustion catalyst. The combustor 7 itself is displaceably constituted continuously. Here, the combustor 7 itself is rotatably constituted. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
[Industrial application fields]
The present invention relates to a fuel cell system. In particular, the present invention relates to a fuel cell system provided with a catalytic combustor.
[0002]
[Prior art]
As a conventional fuel cell system, a fuel exhaust system containing hydrogen discharged from a fuel cell is known to be combusted by a catalytic combustor.
[0003]
For example, combustion exhaust gas generated by burning fuel exhaust gas and oxidant exhaust gas with a catalytic combustor is supplied to an air line that supplies the cathode, or combustion exhaust gas is supplied to a turbine compressor to generate compressed air. (See, for example, Patent Document 1).
[0004]
As a combustion catalyst device, a device in which fuel and air are uniformly mixed and supplied to the combustion catalyst is known. For example, an air supply path for supplying air and a fuel supply pipe for supplying fuel of combustible gas in the air supply path are provided. Also, a mixing chamber that mixes the air and fuel supplied through the air supply pipe by moving in a swirling or spiral flow, and an oxidation reaction of the mixed gas of fuel and air that is arranged downstream of the mixing chamber. And a combustion catalyst for burning. A remixing means for introducing the mixed gas into the combustion catalyst by narrowing the flow of the mixed gas and then diffusing it is provided upstream of the combustion catalyst. Thereby, when the flow of the mixed gas is narrowed or diffused, the mixed gas is remixed and supplied to the combustion catalyst in a sufficiently uniform mixed state (for example, Patent Document 2, reference.).
[0005]
[Patent Document 1]
Japanese Patent Laid-Open No. 11-273701
[Patent Document 2]
JP 2000-274605 A
[0006]
[Problems to be solved by the invention]
In the combustion catalyst used in the fuel cell system described above, in addition to the concentration distribution of hydrogen in the fuel exhaust gas discharged from the fuel cell, the oxidant gas is mixed, and therefore it is necessary to sufficiently mix in the mixer. is there. If the mixed gas supplied to the combustor is non-uniform, the reaction temperature becomes high at a portion where the hydrogen concentration is high, and NOx may be generated. Further, when the reaction temperature becomes higher, the catalyst is deteriorated and the oxidation performance is lowered. On the other hand, in a portion where the hydrogen concentration is low, it is difficult to obtain a stable combustion reaction, and hydrogen may be discharged untreated.
[0007]
Moreover, the water produced | generated with combustion reaction adheres to a catalyst, and there exists a possibility of reducing combustion efficiency.
[0008]
In view of the above problems, an object of the present invention is to provide a fuel cell system capable of suppressing a decrease in reaction efficiency in a catalytic combustor.
[0009]
[Means for solving problems]
Produced in the mixer using a fuel cell that generates power using a fuel gas and an oxidant gas, a mixer that mixes a fuel exhaust gas from the fuel cell and an oxygen-containing gas, and a combustion catalyst A combustor that combusts the mixed gas. The combustor itself is configured to be continuously displaceable so as to reduce the deviation of the mixed gas or generated water in the combustor.
[0010]
[Action and effect]
By configuring the combustor itself to be continuously displaceable so as to reduce the bias of the mixed gas or generated water in the combustor, the mixed gas can be easily distributed into the combustor when supplied, It can suppress that hydrogen becomes high concentration locally. As a result, a decrease in reaction efficiency in the catalytic combustor can be suppressed.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
The configuration of the fuel cell system used in the first embodiment is shown in FIG.
[0012]
A fuel cell 3 is provided that generates power by supplying hydrogen gas as a fuel gas to an anode and air as an oxidant gas to a cathode. As an anode supply system for supplying hydrogen gas to the anode of the fuel cell 3, a hydrogen tank 1 for storing hydrogen in a high pressure state and a hydrogen pressure regulating valve 2 for adjusting the pressure of the hydrogen gas supplied from the hydrogen tank 1 to a predetermined pressure are provided. . In addition, as a cathode supply system that supplies air to the cathode of the fuel cell 3, a compressor 5 that supplies air whose flow rate is adjusted is provided. An air pressure regulating valve 6 for adjusting the cathode pressure is provided on the cathode downstream side of the fuel cell 3. Here, the air pressure regulating valve 6 is provided in the path 17 described later.
[0013]
Further, as a discharge system of the fuel cell 3, a path 16 through which the fuel exhaust gas discharged from the anode flows and a path 17 through which the oxidant exhaust gas discharged from the cathode flow are provided. Moreover, the mixing part 4 which mixes the fuel exhaust gas supplied through the path | route 16, and the oxidizing agent exhaust gas supplied through the path | route 17 is provided. Further, a path 18 through which the mixed gas of the fuel exhaust gas and the oxidant exhaust gas generated by the mixing unit 4 is circulated, and a combustor 7 that combusts the mixed gas supplied through the path 18 are provided. As the combustor 7, a combustor provided with a combustion catalyst is used.
[0014]
Here, the hydrogen concentration in the fuel exhaust gas discharged from the fuel cell 3 may be uneven. Moreover, since the fuel exhaust gas and the oxidant exhaust gas are mixed, the mixed gas itself may be non-uniform. If the hydrogen in the mixed gas is not uniform, the reaction temperature becomes high at a portion where the concentration is high, NOx is generated, and the catalyst may further deteriorate. In addition, in a portion where the concentration is low, the reaction becomes unstable and untreated hydrogen may be discharged. Moreover, since the temperature of the combustion catalyst is non-uniform, there is a problem that it is difficult to detect the presence or absence of an oxidation reaction. In addition, moisture contained in the mixed gas and water generated in association with the combustion reaction may adhere to the catalyst and reduce the reaction efficiency.
[0015]
Therefore, the combustor 7 is configured to be continuously displaceable. Here, the combustor 7 is configured to be displaceable with respect to the supplied mixed gas, whereby the mixed gas is distributed and supplied. Thereby, it is prevented that the hydrogen concentration is locally increased in the combustor 7, and the reaction temperature is made uniform. Further, by composing the combustor 7 so as to be continuously displaceable, at least a part of the water adhering to the combustion catalyst can be removed. A configuration for enabling displacement of the combustor 7 will be described later.
[0016]
The combustion exhaust gas generated by the combustor 7 is discharged to the outside through a path 19 and a path 20 disposed downstream of the combustor 7. Or you may use as temperature adjustment of the air supplied to a cathode, or an inert gas.
[0017]
Further, a cooling system for adjusting the temperature of the fuel cell 3 and the combustor 7 is provided. By cooling the cooling water through the cooling system, the fuel cell 3 and the combustor 7 are cooled. As the cooling system, a cooling water pump 10 for circulating the cooling water is provided. Moreover, the radiator 9 which adjusts the temperature of cooling water is provided. Furthermore, a three-way valve 8 for selecting whether or not to circulate the cooling water to the radiator 9 is provided. Here, the coolant discharged from the combustor 7 is branched by the three-way valve 8 into a path 12 for circulating to the fuel cell 3 and a path 13 for circulating to the radiator 9. The cooling water exchanges heat in one of the fuel cell 3 and the radiator 9 and then merges again, and circulates through the path 14 to the combustor 7.
[0018]
A controller 11 for controlling such a fuel cell system is provided. Based on the temperature, required load, etc. of the fuel cell 3, command values to the hydrogen pressure regulating valve 2, the compressor 5, the air pressure regulating valve 6, the three-way valve 8, and the cooling pump 10 are calculated, and the respective actuators are controlled.
[0019]
Next, a schematic configuration of the exhaust system in such a fuel cell system, in particular, the mixing unit 4, the combustor 7, and the periphery thereof will be described with reference to FIG.
[0020]
Here, the combustor 7 is configured to be rotatable within the cross section of the flow path with respect to the supplied mixed gas. At this time, the substantially central axis of the combustor 7 is set as the rotation axis. For example, the combustor 7 is configured in a substantially cylindrical shape, and the central axis along the flow direction of the mixed gas is configured to be the central axis of rotation.
[0021]
The mixing unit 4 is configured by mixing the fuel exhaust gas from the path 16 having an L-shaped end into the flow in the oxidant exhaust gas flowing through the path 17. The mixing unit 4 and the path 18 are connected so that the path 18 side can be displaced. Here, the path 17 and the path 18 are connected so as to be rotatable on the path 18 side, and this connection portion is referred to as a sliding portion 15a. The combustor 7 and the path 19 are configured to be rotatable in synchronization with the path 18. The path 19 and the path 20 are connected so that the path 19 side can rotate, and this connection portion is referred to as a sliding portion 15b. That is, the path 18, the combustor 7, and the path 19 are configured to be rotatable with respect to the mixed gas supplied from the mixing unit 4. In addition, the sliding part 15 is made into the seal structure, and the gas leak from a connection part is prevented.
[0022]
Further, the combustor 7 includes a case 26 and a catalyst unit 25. Combustion processing is performed by circulating the mixed gas through the combustion section 25. Further, a generated water removing unit 27 that is a removing unit of water generated by the burning unit 25 is provided on the outer peripheral side of the burning unit 25. Here, the generated water removal unit 27 is configured by providing a gap between the combustion unit 25 and the case 26. The shape of the case 26 is not limited to that shown in FIG.
[0023]
By rotating the combustor 7, hydrogen in the mixed gas can be distributed and supplied to the catalyst unit 25. Here, since the combustor 7 is rotated within the cross section of the flow path, the mixed gas can be distributed and supplied to the cross section of the flow path. Moreover, the water produced | generated with combustion in the catalyst part 25 moves outside by the centrifugal force accompanying rotation of the combustor 7. Thereby, the produced water can be moved from the catalyst unit 25 to the produced water removing unit 27.
[0024]
Although not shown here, a combustor cooling system for cooling the combustor 7 is provided. For example, a cooling water path fixed to the system is provided on the outer side of the case 26, and the temperature of the catalyst unit 25 is adjusted by circulating the cooling water supplied through the path 14.
[0025]
Next, the structure of the rotation drive means for rotating the combustor 7 described above will be described. In the following, four configuration examples are shown, but this is not restrictive.
[0026]
A configuration example (first example) of the rotation driving means is shown in FIG.
[0027]
The gear 21 is fixed along the outer periphery of the combustor 7. Moreover, the motor 23 and the gear 22 connected to the motor 23 are provided. The gears 21 and 22 are installed so as to mesh with each other and transmit the rotation of the motor 23.
[0028]
Here, the combustor 7 is rotated by the power of the motor 23. Therefore, the combustor 7 can be rotated at an appropriate time. Moreover, it can set to the rotation speed appropriate for the combustor 7.
[0029]
FIG. 4 shows another configuration example (second example) of the rotation driving means.
[0030]
The combustor 7 is fixed to the rotor 31 of the SR motor 30. Here, the rotor 31 is fixed to the outer periphery of the combustor 7. Here, the rotor 31 is divided into four in the circumferential direction and arranged every 90 degrees. Furthermore, the stator 32 divided into six in the circumferential direction is arranged every 60 degrees via a rotation gap on the outside thereof.
[0031]
Here, the rotation of the combustor 7 is adjusted by driving the SR motor 30. Therefore, the combustor 7 can be rotated in a timely manner. Further, the combustor 7 can be set to an appropriate rotation speed.
[0032]
FIG. 5 shows another configuration example (third example) of the rotation driving means.
[0033]
A water web (water flow guide) 34 is fixed to the outer periphery of the combustor 7. Here, a web 34 extending outward in the radial direction is fixed uniformly on the outer periphery of the substantially cylindrical combustor 7 in the circumferential direction. In addition, a cooling water passage 35 is provided for supplying cooling water to the vicinity of the web 34 so that the combustor 7 rotates. The cooling water flowing through the path 14 shown in FIG. 1 is supplied to the cooling water path 35 and supplied between the webs (water flow guides) 34 adjacent in the circumferential direction. Thereby, the circumferential pressure is applied to the web 34 by the pressure of the cooling water, and the combustor 7 rotates. The rotational speed of the combustor 7 can be controlled by adjusting the flow rate of the cooling water flowing through the cooling water path 35. That is, the rotational speed of the combustor 7 can be controlled by adjusting the load of the cooling pump 10. At this time, the combustor 7 is also cooled by the cooling water, so that it can also serve as the above-described combustor cooling system.
[0034]
In addition, although the water web (water flow guide) 34 has a shape extending in the extending direction of the radius, the present invention is not limited to this. For example, the web 34 may be formed at an angle with respect to the radius. Further, the tip may be formed in an approximately L shape. The size of the web 34 is preferably designed according to the required number of rotations.
[0035]
In such a configuration, the combustor 7 rotates with the circulation of the cooling water. Since the rotation driving means is configured by the structure of the cooling system, the combustor 7 including the rotation driving means can be configured compactly. Moreover, since cooling and rotation can be performed by the same flow of cooling water, electric power consumed with rotation can be suppressed.
[0036]
Next, FIG. 6 shows a configuration example (fourth example) of other rotation driving means.
[0037]
Fins 36 are provided in the vicinity of the outlet of the combustor 7. Here, the fins 36 are attached radially around the axis of the substantially cylindrical combustor 7 and fixed so that the planar portion of the fins 36 has a certain angle with respect to the exit cross section of the combustor 7. When the combustion gas discharged from the combustor 7 collides with the fin 36, a rotational force is generated, and the combustor 7 can be rotated. Here, the fin 36 is provided at the outlet portion of the combustor 7, but the same effect can be obtained even when provided at the inlet portion.
[0038]
In such a configuration, when the mixed gas is supplied to the combustor 7, the combustor 7 rotates. Here, since the mixed gas is always supplied to the combustor 7 during operation of the fuel cell 3, the combustor 7 is always rotating. Since the rotational power is obtained by the supplied gas, the electric power consumed by the rotation can be suppressed.
[0039]
The combustor 7 including any one of the four examples described above is provided, and the combustor 7 is continuously displaced while the mixed gas is supplied to the combustor 7. Here, since the fuel exhaust gas from the anode of the fuel cell 3 is always supplied to the combustor 7, the combustor 7 is always rotated during the hydrogen gas supply.
[0040]
It is always rotated during operation of the fuel cell system. For example, in the case of using the combustor 7 provided with the rotation driving means shown in the first and second examples, the rotation of the combustor 7 is started when the system start signal is detected, and the stop signal is detected to detect hydrogen. After stopping the supply, the rotation of the combustor 7 is stopped. By always rotating the combustor 7, it is possible to always supply the mixed gas uniformly and to prevent moisture from adhering to the catalyst unit 25.
[0041]
In addition, you may provide the fin 36 with respect to the combustor 7 provided with either of the rotational drive means shown to the 1st-3rd example. By providing the fins 36, the mixed gas can be taken into the combustor 7 or the combustion exhaust gas can be discharged smoothly from the combustor 7.
[0042]
Further, the displacement direction is not limited to the rotation direction, and may be any displacement in at least one of the three-dimensional directions. For example, if it is configured to be displaceable parallel to the gas flow path cross section in the combustor 7, the supplied mixed gas can be distributed in the movement direction in the gas flow path cross section. Moreover, the distance of the mixing part 4 downstream side can be changed by moving to an axial direction. Thereby, since the degree of diffusion of the fuel exhaust gas can be changed, the hydrogen concentration distribution of the mixed gas in the vicinity of the inlet of the combustor 7 can be changed. In addition, when moving to at least one of the three-dimensional directions, it is preferable that water is removed outside the catalyst unit 25 in accordance with the moving direction.
[0043]
Next, the effect of this embodiment will be described.
[0044]
Produced in the mixing unit 4 using a fuel cell 3 that generates power using a fuel gas and an oxidant gas, a mixing unit 4 that mixes a fuel exhaust gas from the fuel cell 3 and an oxygen-containing gas, and a combustion catalyst And a combustor 7 for subjecting the mixed gas to combustion treatment. The combustor 7 itself is configured to be continuously displaceable so as to reduce the deviation of the mixed gas or generated water in the combustor 7. By displacing the combustor 7, the supplied mixed gas can be easily distributed and supplied into the combustor 7. Furthermore, by making the combustor 7 displaceable, moisture in the combustor 7 can be easily removed from the catalyst portion 25. Thereby, the fall of the combustion efficiency in the combustor 7 can be suppressed.
[0045]
Here, the combustor 7 itself is configured to be continuously displaceable with respect to the supplied mixed gas, whereby hydrogen in the mixed gas is distributed and supplied to the combustion catalyst. Even when a non-uniform mixed gas is supplied, it is possible to avoid a gas having a high hydrogen concentration from being continuously supplied to a specific location. As a result, the reaction temperature can be made uniform to prevent catalyst deterioration. In addition, the presence or absence of an oxidation reaction can be easily detected by making the reaction temperature uniform.
[0046]
Further, the combustor 7 itself is configured to be displaceable so that at least a part of the moisture in the vicinity of the combustion catalyst can be removed. As a result, efficiency reduction due to water adhering to the combustion catalyst can be suppressed.
[0047]
For example, the combustor 7 itself is configured to vibrate in at least one of the three-dimensional directions. By shifting the position of the combustor 7 in the front-back, left-right, and up-down directions, the portion where the hydrogen concentration of the mixed gas enters the combustor 7 can be shifted, so that a part of the combustion catalyst is prevented from deteriorating. Can do.
[0048]
Or combustor 7 itself is comprised so that rotation around the axial center of a mixed gas distribution direction is possible. Thereby, even if the mixed gas supplied to the combustor 7 is non-uniform, the homogenization progresses inside and the oxidation reaction progresses. Therefore, a part of the catalyst can be prevented from being deteriorated and the reaction temperature is made uniform, so that the temperature control of the combustor 7 becomes easy. By further rotating, a centrifugal force is generated, and generated water and condensed water adhering to the catalyst surface by the centrifugal force can be moved to the outside, and a reaction can be easily generated.
[0049]
A motor 23 serving as a rotational drive source for the combustor 7, a first gear 21 disposed outside the combustor 7, and a second gear 22 that meshes with the first gear 21 and transmits the rotational drive force of the motor 23. Prepare. With this configuration, the motor 23 can be driven to vary the rotational speed of the combustor 7 very finely.
[0050]
Alternatively, a water web (water flow guide) 34 fixed around the combustor 7 and a cooling water path 35 through which the refrigerant flows along the outer periphery of the combustor 7 including the water web 34 are provided. Thereby, by rotating the combustor 7 using the force through which the cooling water flows, cooling and rotation can be performed with the same configuration, and the combustor 7 can be made compact.
[0051]
Alternatively, the combustor 7 is configured to be rotatable by incorporating the combustor 7 into the rotor 31 portion of the motor 30. With this configuration, the motor 23 can be driven to vary the rotational speed of the combustor 7 very finely. Further, the combustor 7 and the rotation mechanism (the motor 30) can be integrated and miniaturized.
Alternatively, the fins 36 are provided at the inlet or the outlet of the combustor 7, and the combustor 7 is configured to be rotatable by the force of the mixed gas flowing into the combustor 7 or the combustion exhaust gas flowing out from the combustor 7. By disposing the fins 36, the combustor 7 is rotated by the force of the mixed gas flowing in or the force of the gas discharged by the combustor 7, so that the rotation driving means can be reduced in size.
[0052]
In the first to third rotation driving means, fins 36 are provided at the inlet or outlet of the combustion 7, and the fins 36 are rotated in synchronization with the combustor 7. Thereby, the effect of pushing or sucking the mixed gas into the combustor 7 is obtained, and the pressure loss is reduced.
[0053]
Here, the combustor 7 is continuously displaced while the fuel cell system is operating. As a result, the combustion reaction is stabilized because the mixed gas is always made uniform. Moreover, it can suppress that reaction stops because the hydrogen concentration becomes low in part, and conversely, the reaction heat increases and the catalyst deteriorates when the concentration becomes high. Further, the produced water can be constantly moved to the outside, and the produced water can be prevented from adhering to the catalyst and hindering the combustion reaction.
[0054]
Next, a second embodiment will be described. The configuration of the fuel cell system is shown in FIG. Hereinafter, a description will be given centering on differences from the first embodiment.
[0055]
A circulation channel 50 is provided on the anode side of the fuel cell 3. The fuel exhaust gas discharged from the anode is supplied again to the fuel cell 3 through the circulation channel 50. Further, the fuel gas circulating through the circulation channel 50 can be selectively supplied to the mixing unit 4 via the purge valve 51. Here, the purge valve 51 is provided in the path 16 connected to the circulation flow path 50, and the purge valve 51 is opened so that the fuel gas in the anode can be purged.
[0056]
Nitrogen moves and accumulates at the anode during operation, thereby reducing the reaction efficiency in the fuel cell 3. In order to prevent this, by purging the anode in a timely manner, the hydrogen gas concentration at the anode is restored to maintain efficiency.
[0057]
Further, an oxidation reaction detection means for detecting an oxidation reaction in the combustor 7 is provided. Here, the hydrogen concentration sensor 28 is provided in the catalyst unit 25 as an oxidation reaction detecting means.
[0058]
Next, a method for controlling the rotation of the combustor 7 in the fuel cell system having such a configuration will be described. In addition, as the combustor 7 used here, for example, the combustor provided with the rotation driving means shown in the first and second examples is used.
[0059]
Immediately before supplying the mixed gas, the rotational speed of the combustor 7 is increased. Here, when the purge 51 is closed, the rotation of the combustor 7 is stopped. When a signal requesting the purge of the anode is detected, or when it is predicted that the purge of the anode is required, the rotation of the combustor 7 is started. The combustor 7 is rotated by driving the motor 23 when the first rotation driving means is used and driving the SR motor 30 when the second rotation driving means is used. Thus, rotation of the combustor 7 is started immediately before the mixed gas is supplied to the combustor 7.
[0060]
When the purge 51 is closed, the rotational speed of the combustor 7 may be suppressed and the rotational speed may be increased immediately before the mixed gas is supplied. In this case, the present invention can be applied to any of the rotation driving means shown in the first to fourth examples. For example, when the rotational drive means shown in the third example is used, the cooling water temperature circulating through the fuel cell 3 is set to the operating temperature of the fuel cell 3. When a signal requesting the purge of the anode is detected, or when the purge of the anode is predicted, the cooling water flow rate is increased by increasing the load of the cooling pump 10. Thereby, since the flow volume of the cooling water which flows into the cooling water path | route 35 can be increased, the rotation speed of the combustor 7 can be increased.
[0061]
Further, when the rotation driving means shown in the fourth example is used, the combustor 7 is rotated by the oxidant exhaust gas at the normal time. When an anodic purge request signal or an anode purge is predicted, the flow rate of the oxidant gas supplied to the fuel cell 3 is increased. In this case, it is necessary to keep the cathode pressure constant by the air pressure regulating valve 6.
[0062]
Alternatively, air may be used as the oxidant used in the combustor 7 in the rotation driving means shown in the fourth example. In this case, for example, by providing a compressor or the like (not shown), the flow rate of the gas supplied to the combustor 7 can be changed, and thus the rotational speed of the combustor 7 can be controlled. In the case of such a configuration, as described above, it is possible to stop or rotate at a low speed in normal times, and to increase the rotational speed immediately before purge is performed.
[0063]
Thus, by increasing the rotational speed of the combustor 7 immediately before supplying the mixed gas, water on the catalyst surface of the catalyst unit 25 can be removed before the mixed gas is supplied. Combustion of the mixed gas can be started quickly. Further, by stopping the rotation at normal times and increasing the rotation speed of the combustor 7 immediately before supplying the mixed gas, it is possible to suppress the power consumption accompanying the rotation. Or, the rotation speed of the combustor 7 can be controlled with high reactivity while suppressing the rotation speed in normal times and increasing the rotation speed of the combustor 7 immediately before supplying the mixed gas. Can do.
[0064]
Moreover, if an oxidation reaction is detected in the combustor 7 after the start of rotation, the rotation is stopped.
[0065]
Here, it is determined by the hydrogen concentration sensor 28 whether or not an oxidation reaction has occurred in the combustor 7. Even if a non-uniform mixed gas enters the combustor 7, once the chemical reaction occurs uniformly in the combustor 7, the reaction proceeds stably. Therefore, energy for rotating the combustor 7 can be saved by stopping the rotation after confirming that a chemical reaction has occurred inside the combustor 7.
[0066]
Note that the combustor 7 is rotated during the supply of the mixed gas when there is a possibility that the catalyst portion 25 may locally become high temperature due to the oxidation reaction, such as when the mixed gas is supplied for a long time by purging. Is preferred. In this case, the rotation is stopped or suppressed when the purge valve 51 is closed or when a predetermined time has elapsed since the purge valve 51 was closed.
[0067]
Next, the effect of this embodiment will be described. Only the effects different from those of the first embodiment will be described below.
[0068]
Immediately before supplying the mixed gas to the combustor 7, the displacement of the combustor 7 is increased. Here, the rotational speed is increased immediately before the mixed gas is supplied to the combustor 7. Thereby, the water of the catalyst surface can be moved outside. Therefore, since at least a part of the water adhering to the catalyst can be removed to ensure a contact area between the combustion catalyst and the mixed gas, the oxidation reaction can be started quickly.
[0069]
An oxidation reaction detecting means for detecting the presence or absence of an oxidation reaction in the combustor 7 is provided. Here, a hydrogen concentration sensor 28 is provided. When the oxidation reaction is detected, the combustor 7 is stopped. Even if an inhomogeneous mixed gas enters, once the oxidation reaction has uniformly occurred inside the combustor 7, the reaction proceeds stably. Therefore, when it is confirmed that an oxidation reaction has occurred inside the combustor 7, the rotation of the combustor 7 is stopped. Thereby, energy consumed by rotation of the combustor 7 can be suppressed while avoiding discharging unreacted hydrogen.
[0070]
Also in the fuel cell system as shown in FIG. 7, when the purge interval is short, the rotation of the combustor 7 may be constantly maintained as in the first embodiment.
[0071]
Next, a third embodiment will be described. Although the fuel cell system used in the first embodiment will be described here, the same control can be performed even when the temperature sensor 29 is provided in the fuel cell system used in the second embodiment. Hereinafter, a description will be given centering on differences from the first embodiment. In addition, you may use the combustor 7 provided with any rotation drive means shown to the 1st-4th example.
[0072]
The rotation of the combustor 7 is stopped simultaneously with power generation stop or hydrogen gas supply stop. After a predetermined time elapses, the combustor 7 is temporarily rotated.
[0073]
After a while after stopping the power generation or the supply of hydrogen gas, hydrogen in the mixed gas disappears and the catalytic reaction stops. Thereafter, when the temperature in the catalyst unit 25 decreases, condensed water is generated from the mixed gas containing moisture in the combustion unit 25. When this adheres to the catalyst surface of the catalyst portion 25, the reaction rate is lowered when the combustion reaction is started next. Therefore, the power generation is stopped or the supply of hydrogen gas is stopped, and the combustor 7 is temporarily rotated after a predetermined time, for example, when condensed water is generated. Thereby, the condensed water in the catalyst part 25 can be moved outside by a centrifugal force, and the next combustion reaction can be started rapidly.
[0074]
Alternatively, rotation of the combustor 7 may be stopped simultaneously with power generation stop or hydrogen gas supply stop, and when the temperature in the combustor 7 decreases, the combustor 7 may be temporarily rotated.
[0075]
Here, a temperature sensor 29 that detects the temperature in the combustor 7 is provided. When the temperature in the combustor 7 is equal to or lower than a predetermined temperature, for example, below the condensation temperature of water, condensed water is generated in the catalyst unit 25. Therefore, by rotating the combustor 7, the condensed water is moved to the outside, here, the generated water removing unit 27 by centrifugal force. As a result, it is possible to prevent the condensed water from adhering to the catalyst unit 25, and the next combustion reaction can be started promptly.
[0076]
When the rotation driving means shown in the first and second examples is used, the combustor 7 is rotated by supplying power to the motor 23 or the SR motor 30 at an appropriate time after the fuel cell system is stopped. In the case of using the rotation driving means shown in the third example, after stopping the fuel cell system, the cooling pump 10 is driven in a timely manner to circulate cooling water and rotate the combustor 7. Further, when the rotation driving means shown in the fourth example is used, after the fuel cell system is stopped, the compressor 5 is driven in a timely manner so that air is circulated and the combustor 7 is rotated.
[0077]
In addition, although it was set as rotation of the combustor 7 here, it is not this limitation. Any configuration that can remove the condensed water in the combustor 7 by displacing the combustor 7 may be used. For example, it may be configured to be displaceable in three directions. As described above, the next combustion reaction can be smoothly started by temporarily displacing after power generation or hydrogen supply is stopped.
[0078]
Next, the effect of this embodiment will be described. Hereinafter, only effects different from the first and second embodiments will be described.
[0079]
Power generation is stopped or fuel gas supply is stopped, and the combustor 7 is temporarily changed after a predetermined time has elapsed. Thereby, at least a part of the water adhering to the combustion catalyst can be removed, and when the mixed gas is supplied to the combustor 7 next time, the oxidation reaction can be started quickly. Here, power generation is stopped or fuel gas supply is stopped, and the combustor 7 is temporarily rotated after a predetermined time has elapsed. As a result, moisture is removed to the outside of the combustion unit 25 by centrifugal force, so that the next oxidation reaction can be started quickly.
[0080]
A temperature sensor 29 for detecting the temperature of the combustor 7 is provided, and after the power generation is stopped or the supply of the fuel gas is stopped, when the temperature of the combustor 7 falls to a predetermined temperature, the combustor 7 is temporarily displaced. . Thereby, at least a part of the water adhering to the combustion catalyst can be removed, and when the mixed gas is supplied to the combustor 7 next time, the oxidation reaction can be started quickly. At this time, the combustor 7 is fluctuated only when it is predicted that condensed water is attached to the catalyst unit 25, so that power consumption associated with displacement can be suppressed. Here, the combustor 7 is temporarily rotated when the temperature falls to a predetermined temperature. Thereby, at least a part of moisture can be removed by centrifugal force.
[0081]
Next, a fourth embodiment will be described. The configuration of the fuel cell system is the same as that of the first embodiment. However, the structure of the combustor 7 and its periphery is shown in FIG.
[0082]
It arrange | positions so that the axial direction of the combustor 7 may become a substantially perpendicular direction. In other words, it arrange | positions so that mixed gas may distribute | circulate the inside of the combustor 7 in a substantially perpendicular direction. Here, the inlet side is arranged downward and the outlet side is arranged upward. Further, the case 26 is extended to the path 18. As a result, the generated water removing unit 27 that is a gap formed between the case 26 and the catalyst unit 25 is extended to a gap between the case 26 and the path 18. Here, in particular, the generated water removing unit 27 is configured to cover up to the sliding unit 15a. As a result, the generated water / condensed water generated in the combustor 7 is accumulated in the vicinity of the sliding portion 15 a that is a connection portion between the path 17 and the path 18. In this way, the connecting portion on the mixed gas inlet side between the fixed portion and the movable portion including the combustor 7, here, the sliding portion 15 a is configured to be covered with water. The accumulated water can ensure the sealing performance of the sliding portion 15a, and can prevent the mixed gas containing hydrogen supplied to the combustor 7 from leaking.
[0083]
Note that the schematic configuration of the combustor 7 of the present embodiment can be applied to the fuel cell system used in any of the first to third embodiments. Furthermore, the present invention may be applied to a fuel cell system that can be displaced not only in rotation but in at least one of three directions.
[0084]
Next, the effect of this embodiment will be described. Only the effects different from those shown in the first to third embodiments will be described below.
[0085]
The combustor 7 is configured so that the mixed gas flows in a substantially vertical direction. Condensed water due to temperature drop and product water accompanying the reaction move downward according to gravity, so that water adhering to the catalyst surface of the catalyst unit 25 can be eliminated.
[0086]
Further, the inside of the combustor 7 is configured so that the mixed gas circulates substantially from the bottom to the top. Of the connecting parts between the fixed part fixed to the system and the movable part including at least the combustor 7 configured to be displaceable with respect to the system, the connecting part (sliding part 15a) arranged on the lower side. ) A generated water removing unit 27 for collecting water generated by the combustor 7 is provided in the vicinity. Thereby, the sliding part 15a can be covered and sealed with water, and the gas containing hydrogen can be prevented from leaking outside.
[0087]
In the above embodiment, the oxidant exhaust gas is used for the combustion reaction in the combustor 7, but this is not restrictive. In addition, the mixer 4 is configured to mix the fuel exhaust gas flowing through the path 16 into the oxidant exhaust gas flowing through the path 17. However, the present invention is not limited to this. .
[0088]
Thus, it goes without saying that the present invention is not limited to the above embodiment, and various modifications can be made within the scope of the technical idea described in the claims.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of a fuel cell system used in a first embodiment.
FIG. 2 is a configuration diagram around a mixing unit and a combustor used in the first embodiment.
FIG. 3 is a diagram illustrating a configuration example (first example) of a rotation driving unit used in the first embodiment.
FIG. 4 is a diagram illustrating a configuration example (second example) of a rotation driving unit used in the first embodiment.
FIG. 5 is a diagram illustrating a configuration example (third example) of a rotation driving unit used in the first embodiment;
FIG. 6 is a diagram illustrating a configuration example (fourth example) of a rotation driving unit used in the first embodiment.
FIG. 7 is a schematic configuration diagram of a fuel cell system used in a second embodiment.
FIG. 8 is a configuration diagram around a mixing unit and a combustor used in a fourth embodiment.
[Explanation of symbols]
3 Fuel cell
4 mixing section
7 Combustor (combustion section)
15 Sliding part (connection part)
21 1st gear
22 Second gear
23 Motor
25 Catalyst part
27 Generated water removal section
28 Hydrogen concentration sensor (Oxidation reaction detection means)
29 Temperature sensor (temperature detection means)
30 motor
31 rotor
34 Water web (water flow guide)
35 Cooling water path (refrigerant flow path)
36 fins

Claims (15)

A fuel cell that generates power using fuel gas and oxidant gas;
A mixer for mixing the fuel exhaust gas from the fuel cell and an oxygen-containing gas;
A combustor that uses a combustion catalyst to combust the mixed gas generated in the mixer, and
A fuel cell system, wherein the combustor itself is configured to be continuously displaceable so as to reduce the deviation of mixed gas or generated water in the combustor. The fuel cell system according to claim 1, wherein the combustor itself is configured to be able to vibrate in at least one of three-dimensional directions. 2. The fuel cell system according to claim 1, wherein the combustor itself is configured to be rotatable around an axis in a mixed gas flow direction. The fuel cell system according to claim 1, wherein the displacement of the combustor is increased immediately before supplying the mixed gas to the combustor. Comprising an oxidation reaction detection means for detecting the presence or absence of an oxidation reaction in the combustor;
The fuel cell system according to claim 1, wherein the combustor is stopped when an oxidation reaction is detected. 2. The fuel cell system according to claim 1, wherein power generation is stopped or fuel gas supply is stopped, and the combustor is temporarily displaced after a predetermined time has elapsed. Temperature detecting means for detecting the temperature of the combustor,
2. The fuel cell system according to claim 1, wherein after the power generation is stopped or the supply of the fuel gas is stopped, the combustor is temporarily displaced when the temperature of the combustor decreases to a predetermined temperature. The fuel cell system according to claim 1, wherein the combustor is configured so that the mixed gas flows in the vertical direction. In the combustor, the mixed gas is configured to circulate from below to above,
Of the connecting parts between the fixed part fixed to the system and the movable part including at least the combustor configured to be displaceable with respect to the system, in the vicinity of the connecting part disposed on the lower side, the combustor The fuel cell system according to claim 8, further comprising a generated water removing unit that accumulates the water generated in step 1. A motor as a rotational drive source of the combustor;
A first gear disposed outside the combustor;
The fuel cell system according to claim 3, further comprising a second gear that meshes with the first gear and transmits a rotational driving force of the motor. A webbed fixed around the combustor;
The fuel cell system according to claim 3, further comprising a refrigerant flow path for circulating a refrigerant along an outer periphery of the combustor including the web. The fuel cell system according to claim 3, wherein the combustor is configured to be rotatable by incorporating the combustor into a rotor portion of a motor. A fin at the inlet or outlet of the combustor;
The fuel cell system according to claim 3, wherein the combustor is configured to be rotatable by a mixed gas flowing into the combustor or a combustion exhaust gas flowing out from the combustor. A fin at the inlet or outlet of the combustor;
The fuel cell system according to any one of claims 10 to 12, wherein the fin is rotated in synchronization with the combustor. The fuel cell system according to claim 1, wherein the combustor is continuously displaced while the fuel cell system is operating.

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