JP5358966B2 - Fuel cell system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To stably remove carbon monoxide in a selective oxidation reactor with relatively simple structure. <P>SOLUTION: A fuel cell system 1 includes a reformer 4 reforming fuel and water into hydrogen; an inlet port 44 taking in a product in the reformer 4; a passage 45 communicating with the inlet port 44; a catalyst 50 arranged in the passage 45; the selective oxidation reactor 8 having a plurality of outlet ports 45-49 communicating with the passage 45 in positions having different distances to the inlet port 44; a fuel cell 20 having an anode 22, a cathode 23, and an electrolyte membrane 21 arranged between them; and a selecting device 10 selecting any of the plurality of outlet ports 45-49 and making it communicate with the anode 22. <P>COPYRIGHT: (C)2009,JPO&amp;INPIT

Description

  The present invention relates to a fuel cell system, and more particularly to a fuel cell system having a reformer, a selective oxidation reactor, and a fuel cell.

  In recent years, as a clean power source with high energy conversion efficiency, fuel cells that generate electrical energy by electrochemical reaction of hydrogen have begun to be applied to portable electronic devices and the like. Hydrogen used in such a fuel cell may be generated from methanol and water by a small chemical reactor, for example. A small chemical reaction apparatus has a reformer, a selective oxidation reactor, and the like. The vaporized fuel and water are reformed into hydrogen gas by the reformer, and carbon monoxide, which is a by-product generated in the reformer, is almost removed by the selective oxidation reactor. Hydrogen gas is delivered to the anode of the fuel cell.

  The reformer and the selective oxidation reactor cause a reaction using a catalyst. Examples of the reformer include Cu / ZnO as a catalyst used for a steam reforming reaction in which methanol fuel and water are reacted to obtain hydrogen and carbon dioxide. Part of the hydrogen and carbon dioxide produced by the steam reforming reaction produces carbon monoxide by an aqueous reverse shift reaction that proceeds sequentially. Since carbon monoxide poisons the anode of the fuel cell, the carbon monoxide is selectively oxidized in the selective oxidation reactor. As the catalyst used in the selective oxidation reactor, noble metal catalysts such as Pt are widely used. In particular, Pt adsorbs carbon monoxide at a relatively low temperature and promotes its oxidation, and the accompanying oxidation reaction of hydrogen is relatively suppressed. Therefore, carbon monoxide in the reformed gas is converted into a catalyst for a fuel cell. Is mainly used as an active component of a catalyst for reducing the concentration to such a level that it is not significantly poisoned.

  Factors that determine the performance of the reaction in the selective oxidation reactor include the reaction temperature, the concentration of carbon monoxide at the inlet and the amount of oxygen relative thereto, the activity and selectivity of the catalyst, and the contact time. The selective oxidation reaction is very sensitive to these reaction determinants, and since the allowable amount of carbon monoxide in the gas introduced into the subsequent fuel cell is low, the conversion rate is high. Is required. Deviations from the reaction determinants described above may cause, for example, the result that the oxidation of carbon monoxide does not proceed and only the oxidation of hydrogen is caused, and as a result, the carbon monoxide cannot be completely removed.

Here, the contact time with the catalyst is considered. In the case of a reactor with a long contact time, carbon monoxide is once sufficiently reduced in the selective oxidation reactor, but carbon monoxide is converted from carbon dioxide and a large excess of hydrogen by an aqueous reverse shift reaction that occurs sequentially. Water continues to be generated, and carbon monoxide in the gas derived from the selective oxidation reactor cannot be sufficiently removed. On the other hand, in the case of a reactor having a short contact time, the reaction time until the carbon monoxide is sufficiently reduced cannot be secured, and the carbon monoxide is not sufficiently removed. Therefore, it is necessary to keep the contact time properly. However, the contact time varies depending on factors such as fluctuations in the flow rate of gas sent from the reformer to the selective oxidation reactor, and the selective oxidation reactor. As the gas flow rate in the chamber changes and the temperature of the catalyst surface changes, the optimum contact time for the reaction changes. In view of such a state, in the technique described in Patent Document 1, the selective oxidizing reaction is generated in multiple stages by dividing the oxidizing agent introduction part so that the selective oxidizing reaction occurs stepwise.
JP 2000-285949 A

However, in the technique described in Patent Document 1, it is necessary to prepare the number of divided oxidizer introduction portions, and further, a means for controlling the flow rate is required. Therefore, such a technique can be used for a relatively large fuel cell system, but is not necessarily suitable for a fuel cell system for an electronic device that is desired to be compact.
Accordingly, an object of the present invention is to enable stable removal of carbon monoxide in a selective oxidation reactor with a relatively simple structure.

In order to solve the above problems, according to the invention according to claim 1,
A reformer that reforms fuel and water into hydrogen;
An inlet port for taking in a product from the reformer, a flow path leading to the inlet port, a catalyst provided in the flow path, and a plurality of paths leading to the flow path at different positions to the inlet port A selective oxidation reactor having an outlet port;
A fuel cell having an anode, a cathode, and an electrolyte membrane provided therebetween;
A selector that selects any of the plurality of outlet ports and communicates with the anode;
A controller for controlling the selector;
A temperature detector for detecting the temperature of the anode;
With
Fuel cell system the controller is characterized that you control the selector based on the temperature detected by the temperature detector is provided.

According to the invention of claim 2 ,
The controller switches an outlet port to be selected from the plurality of outlet ports to an outlet port far from the inlet port next to the selected outlet port each time the temperature detected by the temperature detector reaches a predetermined threshold value. The fuel cell system according to claim 1 , wherein the fuel cell system is provided with the selector.

According to the present invention, when the outlet port is switched by the selector, the distance that hydrogen, carbon monoxide, and the like flow through the flow path of the selective oxidation reactor is switched. Therefore, even if the reaction environment changes, an outlet port corresponding to the reaction environment can be selected, and the production of carbon monoxide by the aqueous reverse shift reaction can be suppressed while sufficiently removing carbon monoxide. Therefore, removal of carbon monoxide in the selective oxidation reactor can be performed stably.
Further, since the selectors are provided between the selective oxidation reactor and the fuel cell, instead of preparing the oxidant introduction portions for the number of divisions, the fuel cell system itself is not complicated or enlarged.

  Hereinafter, preferred embodiments for carrying out the present invention will be described with reference to the drawings. However, although various technically preferable limitations for implementing the present invention are given to the embodiments described below, the scope of the invention is not limited to the following embodiments and illustrated examples.

[First Embodiment]
FIG. 1 is a block diagram showing a configuration of a fuel cell system 1 according to an embodiment of the present invention. The fuel cell system 1 is mounted on electronic devices such as a notebook personal computer, a PDA, an electronic notebook, a digital camera, a mobile phone, a wristwatch, a register, and a projector.

  The fuel cell system 1 includes a storage unit that stores a fuel container 2 in which liquid fuel is sealed, a pump 3 that sucks the liquid fuel in the fuel container 2, a reaction unit that causes a reaction from the liquid fuel, a fuel cell 20, , Air pumps 25 and 27, a controller 30 and the like. The fuel cell 20 in the fuel cell system 1 generates power, and the electricity generated by the fuel cell 20 is supplied to each part of the electronic device body via the DC / DC converter, and the electronic device body operates. The fuel cell 20 includes an anode 22, a cathode 23, and an electrolyte membrane 21 sandwiched between the anode 22 and the cathode 23.

The electrolyte membrane 21 of the fuel cell 20 is a solid polymer electrolyte membrane. Various catalysts are supported on the anode 22 and the cathode 23. Hydrogen gas or the like is sent to the anode 22, and external air is sent to the cathode 23. The hydrogen supplied to the anode 22 undergoes an electrochemical reaction with oxygen in the air supplied to the cathode 23 via the electrolyte membrane 21, thereby generating electric power between the anode 22 and the cathode 23. Specifically, a reaction such as the following formula (1) occurs at the anode 22, hydrogen ions generated at the anode 22 pass through the electrolyte membrane 21, and a reaction such as the following formula (2) occurs at the cathode 23. .
H ₂ → 2H ⁺ + 2e ⁻ (1)
2H ⁺ + 1 / 2O ₂ + 2e ⁻ → H ₂ O (2)

  The fuel cell 20 is provided with a temperature sensor 24, and the temperature of the fuel cell 20 (particularly the temperature of the anode 22) is detected by the temperature sensor 24 and converted into an electrical signal. The temperature detected by the temperature sensor 24 is output to the controller 30.

  In order to supply external air to the anode 22 of the fuel cell 20, the fuel cell system 1 has an air pump 25. On the other hand, the hydrogen supplied to the anode 22 of the fuel cell 20 is generated from liquid fuel.

  The fuel container 2 stores liquid fuel (for example, any one of methanol, ethanol, and dimethyl ether) and water in a mixed state or separately. Among the components shown in FIG. 1, the fuel container 2 is detachable from the fuel cell system 1, the other components are built in the fuel cell system 1, and the fuel container 2 is attached to the fuel cell system 1. Then, the fuel container 2 and the pump 3 are connected.

  The reaction unit heats the heat insulating package 29 that forms an internal space of an atmosphere that is depressurized from the atmospheric pressure, the vaporizer 4, the heater 5 that heats the vaporizer 4, the reformer 6, and the reformer 6. Heater 7, selective oxidation reactor 8, heater 9 for heating selective oxidation reactor 8, flow path switching selector 10 for switching the flow path of selective oxidation reactor 8, vaporizer 4, reformer 6 And a catalytic combustor 26 that heats at least one of the selective oxidation reactors 8, and a hydrogen combustor 28. The vaporizer 4, the heater 25, the reformer 6, the heater 7, the selective oxidation reactor 8, the heater 9 and the catalytic combustor 26 are accommodated in a heat insulating package 29. The hydrogen combustor 28 is disposed outside the heat insulation package 29, but may be accommodated in the heat insulation package 29. Moreover, although the selector 10 may be accommodated in the heat insulation package 29, it is more preferable to arrange | position outside the heat insulation package 29 from a viewpoint of airtightness and high temperature resistance.

  The pump 3 sends a mixed liquid of fuel and water from the fuel container 2 to the vaporizer 4. The pump 3 is an electrically driven pump and is controlled by the controller 30. A valve controlled by the controller 30 may be interposed between the pump 3 and the vaporizer 4.

  The vaporizer 4 vaporizes the mixed liquid of fuel and water. The heater 5 provided in the vaporizer 4 is made of an electric heating material (for example, Au) whose electric resistance value depends on temperature. Therefore, the heater 5 also functions as a temperature sensor that reads the temperature from the electric resistance value, and the temperature of the vaporizer 4 is converted into an electric signal by the heater 5. The liquid mixture sent from the pump 3 to the vaporizer 4 is vaporized by the heat of the heater 5, and the gas mixture vaporized by the vaporizer 4 is sent to the reformer 6.

The reformer 6 generates hydrogen gas or the like from the water vaporized in the vaporizer 4 and the fuel by a catalytic reaction, and further generates a carbon monoxide gas with a small amount. A flow path is formed inside the reformer 6, and a reforming catalyst (for example, a Cu / ZnO-based catalyst or a Pd / ZnO-based catalyst) is supported on the wall surface of the flow path. The air-fuel mixture sent from the vaporizer 4 to the reformer 6 flows through the flow path of the reformer 6 and reacts with the reforming catalyst. When the fuel is methanol, a chemical reaction represented by the following formula (3) occurs in the reformer 6, and subsequently, an aqueous reverse shift reaction represented by the formula (4) occurs in the reformer 6.
CH ₃ OH + H ₂ O → 3H ₂ + CO ₂ (3)
H ₂ + CO ₂ → H ₂ O + CO (4)

  The reformer 6 is provided with a heater 7 for heating the reformer 6. The catalytic combustor 26 mainly heats the reformer 6 by burning hydrogen sent from the anode 22 of the fuel cell 20. The heater 7 is an electric heating material that also serves as a temperature sensor, like the heater 5. That is, the heater 7 heats the reformer 6 by electricity, and detects the temperature of the reformer 6 and converts it into an electric signal. The steam reforming reaction, which is a reforming reaction in the reformer 6 of Formula (3), is an endothermic reaction, and the combustion heat of the catalytic combustor 26 and the heat of the heater 7 are used for the reforming reaction of the reformer 6.

Hydrogen gas or the like generated by the reformer 6 is sent to the selective oxidation reactor 8, and external air is further sent to the selective oxidation reactor 8 by the air pump 27. The air pump 27 is an electrically driven air pump and is controlled by the controller 30.
The selective oxidation reactor 8 selectively removes carbon monoxide by preferentially oxidizing carbon monoxide with a catalyst as shown in the following formula (5).
2CO + O ₂ → 2CO ₂ (5)

  The selective oxidation reactor 8 is provided with a heater 9, and the selective oxidation reactor 8 is heated by the heater 9. The heater 9 also serves as a temperature sensor like the heater 5. In the selective oxidation reactor 8 as well, the aqueous reverse shift reaction of the formula (4) may be caused in the presence of hydrogen and oxygen.

  The vaporizer 4, the reformer 6, the catalytic combustor 26 and the selective oxidation reactor 8 are accommodated in a heat insulation package 29. The inside of the heat insulation package 29 is in a vacuum state (preferably, the pressure is reduced to 10 Pa or less, more preferably 1 Pa or less), and the heat in the heat insulation package 29 is difficult to dissipate to the outside. The heat insulation package 29 is made of glass or metal, and an infrared reflection film (for example, Au, Ag, Al) is formed on the inner surface of the heat insulation package 29.

  Further, since the proper temperatures of the vaporizer 4, the reformer 6, and the selective oxidation reactor 8 are different from each other, the installation positions and materials of the vaporizer 4, the reformer 6, the selective oxidation reactor 8, the catalytic combustor 26, and the like are different. By being designed, the vaporizer 4, the reformer 6 and the selective oxidation reactor 8 are easily maintained at an appropriate temperature. In the steady state, the selective oxidation reactor 8 is maintained at about 120 ° C., the reformer 6 is maintained at a higher temperature (about 300 to 350 ° C.) than the selective oxidation reactor 8, and the vaporizer 4 is selectively oxidized. The same temperature as the vessel 8 (about 100 to 130 ° C.) is maintained.

  FIG. 2 is a view showing a longitudinal section of the selective oxidation reactor 8 and the selector 10, and FIG. 3 is a transverse sectional view of the selective oxidation reactor 8. Here, the cross section of the selective oxidation reactor 8 shown in FIG. 2 is a cross-sectional view taken along the line II-II shown in FIG. 3, and FIG. It is arrow sectional drawing of the surface along -III.

  As shown in FIGS. 2 and 3, the two substrates 41 and 42 are joined, and this joined body is the main body of the selective oxidation reactor 8. In the joined body of the substrates 41 and 42, a twisted flow path 43 and a plurality of ports 44 to 49 communicating with the flow path 43 are formed. Specifically, a groove is formed in the bonding surface of the substrate 42, and the substrate 41 is bonded to the bonding surface, so that the groove is covered with the substrate 41, and the groove is a flow path 43. .

  The flow path 43 is not branched from one end portion to the other end portion, but is a single channel. The ports 44 to 49 are holes that penetrate from the bonding surface of the substrate 41 to the opposite surface. The port 44 communicates with one end of the flow path 43, and the port 49 communicates with the other end of the flow path 43. The ports 45 to 48 communicate with the flow path 43 between one end and the other end of the flow path 43. The distance along the flow path 43 from the ports 45 to 49 with respect to the port 44 is longer in the order of the port 49, the port 48, the port 47, the port 46, and the port 45. A selective oxidation catalyst (for example, platinum) 50 is supported on the wall surface of the flow path 43. As a method for supporting the selective oxidation catalyst 50, for example, after attaching a photoresist made of a dry film having an opening corresponding to the groove 43 formed in the substrate 42, catalyst particles that become the selective oxidation catalyst 50 are dispersed in the dispersion medium. There is a method in which the photoresist dispersion is applied after the catalyst dispersion liquid dispersed in the substrate is applied by a dispenser, or the catalyst dispersion liquid is applied directly to the groove 43 formed in the substrate 42 by an ink jet nozzle. The heater 9 is provided on the outer surface of the main body of the selective oxidation reactor 8. The selective oxidation catalyst 50 may be another noble metal.

  Port 44 is an inlet port, and ports 45 to 49 are outlet ports. That is, as shown in FIG. 1, the port 44 of the selective oxidation reactor 8 is connected to the reformer 6 and the air pump 27, and the hydrogen gas and monoxide sent from the reformer 6 to the selective oxidation reactor 8. Carbon gas or the like is mixed with air and flows into the flow path 43 through the port 44 of the selective oxidation reactor 8. When hydrogen gas, carbon monoxide gas, air, or the like flows through the flow path 43, carbon monoxide is preferentially oxidized by the selective oxidation catalyst 50. Then, the air-fuel mixture from which carbon monoxide has been removed flows out from the flow path 43 through any of the ports 45 to 49 selected by the selector 10.

  A selector 10 is provided between the outlet ports 45 to 49 of the selective oxidation reactor 8 and the anode 22 of the fuel cell 20. The selector 10 is a flow path switching unit that switches the effective length of the flow path 43. That is, when the selector 10 selects one of the outlet ports 45 to 49 of the selective oxidation reactor 8, the effective length of the flow path 43 becomes the flow path 43 from the inlet port 44 to the selected outlet port. It is determined by the length along. The effective length is the length that contributes to the reaction, and the length that the reactant substantially flows. As the selector 10, a plurality of electromagnetically driven open / close valves or electromagnetically driven directional switching valves can be used. The selector 10 is an electromagnetic drive type, and when the selector 10 is controlled by the controller 30, the selector 10 performs a switching operation. Specifically, the selector 10 has valves 51 to 55, one ends of pipes 61 to 65 are connected to the outlet ports 45 to 49, respectively, and valves are respectively connected to the other ends of the pipes 61 to 65. Input ends of 51 to 55 are provided, output ends of the valves 51 to 55 are connected to an input end of the collecting pipe 66, and an output end of the collecting pipe 66 is connected to the anode 22 of the fuel cell 20. When the controller 30 opens only one of the valves 51 to 55, the outlet port connected to the selected valve is selected.

  The air-fuel mixture from which carbon monoxide has been removed in the selective oxidation reactor 8 is sent to the anode 22 from the outlet port selected by the selector 10 among the outlet ports 45 to 49. As described above, power is generated by an electrochemical reaction through the electrolyte membrane 21, hydrogen is consumed at the anode 22, and oxygen in the air sent by the air pump 23 is consumed at the cathode 23. Hydrogen that has not reacted at the anode 22 is sent to the catalytic combustor 26 together with other products, and hydrogen is combusted in the catalytic combustor 26. Hydrogen that has not burned in the catalytic combustor 26 is sent to the hydrogen combustor 28 together with other products. On the other hand, external air is sent to the hydrogen fuel device 28 by the air pump 27, and hydrogen is burned in the hydrogen combustor 28. Various products are discharged from the hydrogen combustor 28 to the outside. The hydrogen combustor 28 is disposed outside the heat insulation package 29.

  The controller 30 controls the air pumps 25 and 27 to operate and stop the air pumps 25 and 27. Further, the controller 30 controls the pump 3 to increase / decrease the supply amount of the pump 3 and operate / stop the pump 3. Further, the controller 30 adjusts the heating temperature of the heaters 5, 7, 9. Here, when adjusting the outputs of the heaters 5, 7, 9 and the pump 3, the controller 30 sets the outputs of the heaters 5, 7, 9 and the pump 3 based on the temperatures detected by the heaters 5, 7, 9. The controller 30 adjusts the outputs of the heaters 5, 7, 9 and the pump 3 so that the vaporizer 4, the reformer 6, and the selective oxidation reactor 8 are maintained at a predetermined appropriate temperature. As a result, the vaporizer 4, the reformer 6, the selective oxidation reactor 8 and the like are in a steady state, and the vaporizer 4, the reformer 6, and the selective oxidation reactor 8 efficiently vaporize or react.

  When the vaporizer 4, the reformer 6, and the selective oxidation reactor 8 are operating in a steady state, the fuel cell 20 is normally operated in a steady state. However, the chemical equilibrium may be lost in the selective oxidation reactor 8 for some reason, and carbon monoxide may not be sufficiently oxidized in the selective oxidation reactor 8. Therefore, the oxidation capability of the selective oxidation reactor 8 can be adjusted. Specifically, the oxidation operation of the selective oxidation reactor 8 is adjusted by performing the switching operation by the selector 10. That is, since the distance along the flow path 43 from the inlet port 44 to the outlet ports 45 to 49 is longer in the order of the outlet port 49, outlet port 48, outlet port 47, outlet port 46, outlet port 45, selective oxidation. The oxidation capacity of the reactor 8 is higher in the order of the outlet port 49, the outlet port 48, the outlet port 47, the outlet port 46, and the outlet port 45.

  Whether or not carbon monoxide is sufficiently selectively oxidized in the selective oxidation reactor 8 is determined by the temperature of the anode 22 of the fuel cell 20. That is, when the concentration of oxygen in the reformed gas supplied to the anode 22 is high, combustion of hydrogen in the reformed gas tends to occur at the anode 22, and the temperature of the anode 22 rises due to the combustion heat of hydrogen. Further, the oxygen concentration in the reformed gas sent from the selective oxidation reactor 8 to the fuel cell 20 is higher in the selective reactor 8 than in the case where the carbon monoxide is sufficiently selectively oxidized in the selective oxidation reactor 8. It is higher when there is not enough selective oxidation reaction. Therefore, when carbon monoxide is sufficiently selectively oxidized in the selective oxidation reactor 8, much oxygen in the air supplied by the air pump 27 is consumed. Therefore, since the concentration of oxygen supplied to the anode 22 is low, the progress of the hydrogen combustion reaction is suppressed and the temperature of the anode 22 is unlikely to rise. On the other hand, when carbon monoxide is not sufficiently selectively oxidized in the selective oxidation reactor 8, much oxygen in the air supplied by the air pump 27 is not consumed. Therefore, since the concentration of oxygen supplied to the anode 22 is high, the progress of the hydrogen combustion reaction is relatively increased, and the temperature of the anode 22 is likely to rise. In order to detect whether or not carbon monoxide is sufficiently selectively oxidized in the selective reactor 8, a temperature sensor 24 is provided at the anode 22 of the fuel cell 20, and the temperature of the anode 22 is detected by the temperature sensor 24. .

  The temperature detected by the temperature sensor 24 is output to the controller 30. The controller 30 controls the selector 10 based on the temperature detected by the temperature sensor 24 at the anode 22 of the fuel cell 20. Specifically, the controller 30 compares the temperature detected by the temperature sensor 24 with a predetermined threshold value (this threshold value corresponds to the steady temperature of the anode 22 when the fuel cell 20 is operating in a steady state). If the controller 30 determines that the temperature detected by the temperature sensor 24 has reached a predetermined threshold as a result of the comparison, the controller 30 switches the selector 10. More specifically, when the controller 30 switches the selector 10, the selector 10 selects an outlet port to be selected from the outlet ports 45 to 49, next to the outlet port next to the selected outlet port. Switch to the port.

Next, the operation of the fuel cell system 1 and the control operation of the controller 30 will be described with reference to FIG.
First, the controller 30 controls the selector 10, and the selector 10 selects the outlet port 45 closest to the inlet port 44 (step S1). That is, the controller 30 opens only the valve 51 and closes the valves 52 to 55. Accordingly, the selective oxidation of carbon monoxide is performed in the flow path 43 from the inlet port 44 to the outlet port 45, but the selective oxidation of carbon monoxide is not performed in the flow path 43 from the outlet port 45 to the outlet port 49. Therefore, the oxidation ability of the selective oxidation reactor 8 is in the lowest state.

  Then, electric power is supplied to the heaters 5, 7 and 9 by the controller 30, and the vaporizer 4, the reformer 6 and the selective oxidation reactor 8 are heated to their appropriate temperature ranges. Next, the controller 30 drives the pump 3 and the air pumps 25 and 27. Then, the liquid fuel and water in the fuel device 2 are sent to the vaporizer 4, and external air is sent to the selective oxidation reactor 8, the catalytic combustor 26, the hydrogen combustor 28 and the cathode 23. Therefore, the mixed liquid is vaporized by the vaporizer 4, and the fuel / water mixture vaporized by the vaporizer 4 is reformed to hydrogen or the like by the reformer 6, and a small amount of carbon monoxide generated by the reformer 6. Is oxidized in the selective oxidation reactor 8, and electricity is generated by an electrochemical reaction between hydrogen supplied to the anode 22 and oxygen supplied to the cathode 23, and hydrogen that has not reacted in the anode 22 is generated in the catalytic combustor 26. Hydrogen that has been burned and has not reacted in the catalytic combustor 26 is burned in the hydrogen combustor 28. By burning hydrogen in the catalytic combustor 26, the vaporizer 4, the reformer 6, and the selective oxidation reactor 8 are each heated to a desired temperature. The outlet port from which the product is discharged from the selective oxidation reactor 8 is an outlet port selected by the selector 10.

  While the fuel cell 20 is generating power, the controller 30 controls the outputs of the heaters 5, 7, 9 and the pump 3 based on the temperatures detected by the heaters 5, 7, 9. Thereby, the vaporizer 4, the reformer 6, the selective oxidation reactor 8 and the like operate in a steady state.

The controller 30 monitors the temperature detected by the temperature sensor 24 while the vaporizer 4, the reformer 6 and the selective oxidation reactor 8 are in steady operation, and the temperature detected by the temperature sensor 24 is set to a predetermined threshold value. (Step S2).
The concentration range of carbon monoxide contained in the reformed gas discharged from the selective oxidation reactor 8 in the steady state (normal state) is the amount of oxygen in the air supplied by the air pump 27, supplied from the fuel container 2. Is set in advance according to the amount of the mixed liquid of fuel and water, the amount of carbon monoxide produced based on the conversion rate (depending on temperature) in the reformer 6, and even if carbon monoxide is in contact for a long time The concentration of the fuel cell 20 is set so as not to be poisoned. In other words, in a steady state, the amount of oxygen consumed by selective oxidation is large. Therefore, the concentration of oxygen discharged from the selective oxidation reactor 8 is low, and hydrogen combustion reaction does not occur sufficiently. It is less than the above threshold.
On the other hand, since the selective oxidation is not sufficiently performed due to a temporary increase in the flow rate of the reformed gas in the selective oxidation reactor 8, for example, the catalyst of the fuel cell 20 is contacted for a long time. If carbon monoxide having a concentration to be poisoned is discharged from the selective oxidation reactor 8, the oxygen that has been set to be sufficiently consumed in a steady state remains without being consumed. In addition, hydrogen is burned in the fuel cell 20 with a high concentration of oxygen, and the temperature detected by the temperature sensor 24 is equal to or higher than the above threshold value.
As described above, normally, if the entire system including the selective oxidation reactor 8 operates normally, the concentration of oxygen in the gas sent from the selective oxidation reactor 8 to the anode 22 becomes relatively low. For this reason, the temperature detected by the temperature sensor 24 does not reach a predetermined threshold value, and the controller 30 continues to monitor the temperature detected by the temperature sensor 24 (step S2: No).

  On the other hand, if carbon monoxide is not sufficiently oxidized in the selective oxidation reactor 8 for some reason, the concentration of oxygen in the gas sent from the selective oxidation reactor 8 to the anode 22 increases. Therefore, the temperature of the anode 22 rises. When the controller 30 determines that the temperature detected by the temperature sensor 24 has reached a predetermined threshold (step S2: Yes), the controller 30 confirms the outlet port currently selected by the selector 10 (step S3). When the controller 30 confirms that the outlet port selected by the selector 10 is not the outlet port 49 farthest from the inlet port 44 (step S3: No), the controller 30 controls the selector 10 to select the currently selected outlet. Next to the port, it is switched to an outlet port far from the inlet port 44 (step S4). Specifically, the controller 30 closes the currently selected outlet port valve, and then opens the outlet port valve far from the inlet port 44. Then, since the oxidation capability of the selective oxidation reactor 8 is increased, the concentration of oxygen in the gas sent from the selective oxidation reactor 8 to the anode 22 becomes lower, thereby lowering the temperature of the anode 22 and reducing the predetermined threshold value. It is confirmed whether or not it is less than (return to step S2). In this way, the controller 30 continues to monitor the temperature detected by the temperature sensor 24.

  As described above, every time the temperature detected by the temperature sensor 24 reaches the predetermined threshold value in step S2, the outlet port selected by the selector 10 is switched to one far from the inlet port 44 (step S2: No, step S3: No, step S4). When the controller 30 confirms that the outlet port selected by the selector 10 in step S3 is the outlet port 49 that maximizes the effective length of the flow path 43 through which the reformed gas passes (step S3: Yes). The controller 30 stops the pump 3 and the air pumps 26 and 27 and supplies power to the heaters 5, 7 and 9 because the effective length of the flow path 43 cannot be further increased to promote the selective oxidation reaction. Stop (step S5). Thereby, the fuel cell system 1 shuts down. At the same time, the controller 30 outputs an abnormal signal.

According to this embodiment, the effective length of the flow path 43 in the selective oxidation reactor 8 is changed by switching the outlet ports 45 to 49 by the selector 10. In particular, every time the temperature of the anode 22 reaches a predetermined threshold, the effective length of the substantial flow path 43 in the selective oxidation reactor 8 increases. Therefore, it is possible to suppress the production of carbon monoxide due to the aqueous reverse shift reaction while sufficiently removing carbon monoxide. Therefore, removal of carbon monoxide in the selective oxidation reactor 8 can be performed stably.
Further, the plurality of outlet ports 45 to 49 are only provided in the selective oxidation reactor 8, and even if the selective oxidation capability is multistage, the selective oxidation reactor 8 is shared so that the size is not increased. Further, since the selector 10 is provided between the selective oxidation reactor 8 and the fuel cell 20, the fuel cell system 1 itself does not become complicated and large.

  If the temperature of the anode 22 of the fuel cell 20 does not reach the threshold value but the performance of the fuel cell 20 is deteriorated, carbon monoxide in the gas sent from the reformer 6 to the selective oxidation reactor 8. The concentration temporarily increases, or a substance (for example, unreacted methanol) that inhibits the selective oxidation reaction in the selective oxidation reactor 8 is introduced into the selective oxidation reactor 8 in a large amount from the reformer 6. It is considered that the concentration of carbon monoxide in the gas sent to the anode 22 increased temporarily. In such a case, the performance of the fuel cell 20 gradually recovers as the carbon monoxide concentration returns. However, if the carbon monoxide concentration continues to be high, the performance of the fuel cell 20 is significantly degraded. . Therefore, the downstream path of the selector 10 is temporarily switched from the anode 22 to the catalytic combustor 26 by a directional control valve or the like to avoid gas introduction to the anode 22 of the fuel cell 20 and at the same time added to the cathode 23 by the air pump 25. It is better to switch the air to be introduced into the anode 22 to suppress the performance deterioration of the fuel cell 20. Thereafter, when a certain period of time has elapsed, the path downstream of the selector 10 is switched from the catalytic combustor 26 to the anode 22 by a direction control valve or the like, and air introduction to the anode 22 is stopped.

[Second Embodiment]
In the second embodiment, as shown in FIG. 5, the temperature sensor 24 is not provided in the anode 22, but the oxygen concentration sensor 31 is provided in the middle of the path from the selector 10 to the anode 22. The oxygen concentration sensor 31 detects the concentration of oxygen in the gas sent to the anode 22, converts it into an electrical signal, and outputs it to the controller 30. Instead of the oxygen concentration sensor 31, an oxygen sensor that detects oxygen may be provided. The oxygen sensor makes the signal output to the controller 30 high when oxygen is detected in the gas sent to the anode 22, and makes the signal output to the controller 30 low when oxygen is not contained in the gas sent to the anode 22. To do.

Next, the operation of the fuel cell system 1 and the control operation of the controller 30 in the second embodiment will be described with reference to FIG.
First, the controller 30 controls the selector 10, and the selector 10 selects the outlet port 45 closest to the inlet port 44 (step S11). Then, electric power is supplied to the heaters 5, 7 and 9 by the controller 30, and the vaporizer 4, the reformer 6 and the selective oxidation reactor 8 are heated to their appropriate temperature ranges. Next, when the controller 30 drives the pump 3 and the air pumps 25 and 27, the vaporizer 4, the reformer 6, the selective oxidation reactor 8, and the fuel cell 20 are activated. While the fuel cell 20 is generating power, the controller 30 controls the outputs of the heaters 5, 7, 9 and the pump 3 based on the temperatures detected by the heaters 5, 7, 9. Thereby, the vaporizer 4, the reformer 6, the selective oxidation reactor 8 and the like operate in a steady state.

In addition, when the vaporizer 4, the reformer 6, and the selective oxidation reactor 8 are operating in a steady state, the controller 30 monitors the detected concentration by the oxygen concentration sensor 31 and sets the detected concentration by the oxygen concentration sensor 31 to a predetermined value. (Step S12).
The concentration range of carbon monoxide contained in the reformed gas discharged from the selective oxidation reactor 8 in the steady state (normal state) is the amount of oxygen in the air supplied by the air pump 27, supplied from the fuel container 2. The oxygen concentration detected by the oxygen concentration sensor 31 is set in advance according to the amount of the mixed liquid of fuel and water, the amount of carbon monoxide produced based on the conversion rate (depending on temperature) in the reformer 6, etc. If the concentration is low enough to prevent the catalyst of the fuel cell 20 from being poisoned even if carbon monoxide is in contact with the carbon monoxide for a long time, the concentration becomes less than the above threshold.
On the other hand, since the selective oxidation is not sufficiently performed due to a temporary increase in the flow rate of the reformed gas in the selective oxidation reactor 8, for example, the catalyst of the fuel cell 20 is contacted for a long time. If carbon monoxide having a concentration of poisoning is discharged from the selective oxidation reactor 8, the oxygen that has been set to be sufficiently consumed in a steady state remains without being consumed. The high concentration of oxygen detected by the oxygen concentration sensor 31 is equal to or higher than the threshold value.

  Normally, the selective oxidation reactor 8 operates steadily and the concentration of oxygen in the gas sent from the selective oxidation reactor 8 to the anode 22 is low, so that the concentration detected by the oxygen concentration sensor 31 does not reach a predetermined threshold value. . If the detected concentration by the oxygen concentration sensor 31 has not reached the predetermined threshold value, the controller 30 continues to monitor the detected concentration by the oxygen concentration sensor 31 (step S12: No).

  On the other hand, if carbon monoxide is not sufficiently oxidized in the selective oxidation reactor 8 for some reason, the concentration of oxygen in the gas sent from the selective oxidation reactor 8 to the anode 22 becomes relatively high. When the controller 30 determines that the concentration detected by the oxygen concentration sensor 31 has reached a predetermined threshold (step S12: Yes), the controller 30 confirms the outlet port currently selected by the selector 10 (step S13). . When the controller 30 confirms that the outlet port selected by the selector 10 is not the outlet port 49 farthest from the inlet port 44 (step S13: No), the controller 30 controls the selector 10 to select the outlet currently selected. After the port, the outlet port is switched to the outlet port far from the inlet port 44 (step S14). As a result, the oxidation capability of the selective oxidation reactor 8 is increased, so that the concentration of oxygen in the gas sent from the selective oxidation reactor 8 to the anode 22 is further reduced. Then, the process of the controller 30 returns to step S12, and the controller 30 continues to monitor the detected concentration by the oxygen concentration sensor 31.

  As described above, every time the concentration detected by the oxygen concentration sensor 31 reaches a predetermined threshold (in the oxygen sensor, every time oxygen is detected by the oxygen sensor), the outlet port selected by the selector 10 is the next. To the one far from the inlet port 44 (step S12: Yes, step S13: No, step S14). When the concentration detected by the oxygen concentration sensor 31 reaches a predetermined threshold value, the effective length of the flow path 43 through which the reformed gas passes the outlet port selected by the selector 10 is the farthest from the inlet port 44. When the controller 30 confirms that the outlet port 49 is the longest (step S13: Yes), the effective length of the flow path 43 is further increased to promote the selective oxidation reaction and the oxygen concentration cannot be further lowered. The controller 30 stops the pump 3 and the air pumps 26 and 27, and stops the power supply to the heaters 5, 7, and 9 (step S15). At the same time, the controller 30 outputs an abnormal signal.

  According to the present embodiment, every time the concentration of oxygen in the gas sent to the anode 22 reaches a predetermined threshold, the effective length of the flow path 43 in the selective oxidation reactor 8 becomes longer. Therefore, it is possible to suppress the production of carbon monoxide due to the aqueous reverse shift reaction while sufficiently removing carbon monoxide. Therefore, removal of carbon monoxide in the selective oxidation reactor 8 can be performed stably.

[Third Embodiment]
In the third embodiment, as shown in FIG. 7, no temperature sensor is provided on the anode 22, but temperature sensors 34 to 39 are provided on the outlet ports 44 to 49 of the selector 10, respectively. The temperature sensors 34 to 39 detect the temperatures of the products passing through the outlet ports 44 to 49, respectively, convert them into electrical signals, and output them to the controller 30.

Next, the operation of the fuel cell system 1 and the control operation of the controller 30 will be described with reference to FIG.
First, the controller 30 controls the selector 10, and the selector 10 selects the outlet port 45 closest to the inlet port 44 (step S31). Then, electric power is supplied to the heaters 5, 7 and 9 by the controller 30, and the vaporizer 4, the reformer 6 and the selective oxidation reactor 8 are heated to their appropriate temperature ranges. Next, when the controller 30 drives the pump 3 and the air pumps 25 and 27, the vaporizer 4, the reformer 6, the selective oxidation reactor 8, and the fuel cell 20 are activated. While the fuel cell 20 is generating power, the controller 30 controls the outputs of the heaters 5, 7, 9 and the pump 3 based on the temperatures detected by the heaters 5, 7, 9. Thereby, the vaporizer 4, the reformer 6, the selective oxidation reactor 8 and the like operate in a steady state.

  When the vaporizer 4, the reformer 6, and the selective oxidation reactor 8 are operating in a steady state, the controller 30 detects the temperature detected by the temperature sensor 34 provided in the inlet port 44 and the outlet port being selected. The temperature detected by the temperature sensor provided in is monitored, and it is determined whether or not the difference between these detected temperatures is within the normal range (step S32, step S33). That is, the controller 30 compares the difference between these detected temperatures with an upper threshold value and a lower threshold value exceeding the normal range (steps S32 and S33).

Since the reformed gas is discharged from the selective oxidation reactor 8 when carbon monoxide is sufficiently oxidized when the time for which the reactants contact the catalyst in the selective oxidation reactor 8 is appropriate, the selective oxidation reactor 8 In 8 the aqueous reverse shift reaction is not problematic to some extent. At this time, the selective oxidation reaction which is an exothermic reaction has a relatively high temperature in the vicinity of the inlet port 44 where the concentration of carbon monoxide is relatively high, so that the temperature becomes relatively high, and the vicinity of the selected outlet port where the concentration of carbon monoxide is low Then, since the reaction rate is low, the temperature is relatively low. Therefore, the temperature range A in the normal range obtained by subtracting the temperature in the vicinity of the selected outlet port from the temperature in the vicinity of the inlet port 44 in the steady state (normal state) as described above is a positive value.
Further, in the flow path 43 in the selective oxidation reactor 8, carbon monoxide stays in the flow path 43 due to some reason, for example, the velocity of the reformed gas flow in the selective oxidation reactor 8 temporarily decreases. If the time to perform is increased, the probability of contact with the catalyst in the flow path 43 is increased or the time for contact with the catalyst is increased, and the carbon monoxide is selectively oxidized before reaching the vicinity of the selected outlet port. End up. For this reason, in the subsequent flow path 43, the concentration of carbon dioxide is increased, causing an aqueous reverse shift reaction together with hydrogen in the reformed gas, and the ratio of carbon monoxide in the reformed gas is increased again. In some cases, the concentration of carbon monoxide in the reformed gas discharged from the outlet port thus formed may reach such a level that the catalyst of the fuel cell 20 is poisoned by contact with the reformed gas for a long time. In such a case, in the vicinity of the selected outlet port, the rate of the selective oxidation reaction is sufficiently low and the aqueous reverse shift reaction, which is an endothermic reaction, proceeds and is cooled to a relatively low temperature. Accordingly, the temperature range B obtained by subtracting the temperature near the selected outlet port from the temperature near the inlet port 44 at this time is higher than the temperature range A, and the lower limit of the temperature range B is the upper threshold value.
Then, in the flow path 43 in the selective oxidation reactor 8, for some reason, for example, the flow rate of the reformed gas in the selective oxidation reactor 8 is temporarily increased, so that the carbon monoxide is not sufficiently oxidized, For this reason, it is considered that carbon monoxide having such a concentration that the catalyst of the fuel cell 20 is poisoned by the contact for a long time remains. In the selective oxidation reactor 8 in this case, since the selective oxidation reaction which is an exothermic reaction does not sufficiently occur, the concentration of carbon monoxide is relatively high in the vicinity of the selected outlet port, in other words, compared with the steady state. The reaction rate increases and the temperature becomes relatively high. The temperature range C obtained by subtracting the temperature near the selected outlet port from the temperature near the inlet port 44 at this time is lower than the temperature range A, and the upper limit of the temperature range C is the lower threshold value.
That is, in the steady state, the temperature difference between the temperature near the inlet port 44 and the temperature near the selected outlet port is within the normal temperature range A, and the temperature detected by the temperature sensor 34 and the temperature detected by the temperature sensor at the selected outlet port are different. Since the difference is greater than the lower threshold and less than the upper threshold, the controller 30 detects the temperature detected by the temperature sensor 34 and the temperature detected by the temperature sensor of the selected outlet port, and monitors whether the temperature is within the normal temperature range A. (Step S32, step S33).

  If the carbon monoxide exceeds the degree of sufficient reaction in the selective oxidation reactor 8 for some reason, it takes a long time for the reactants to contact the catalyst in the selective oxidation reactor 8. Therefore, carbon monoxide having a concentration sufficient to poison the catalyst of the fuel cell 20 is generated by contact for a long time. Therefore, the difference between the temperature near the inlet port 44 and the temperature near the selected outlet port exceeds the upper limit value of the normal temperature range A. Then, the difference between the temperature detected by the temperature sensor 34 and the temperature detected by the temperature sensor at the selected outlet port reaches the upper threshold value or more. If the controller 30 judges that (step S32: Yes), the controller 30 will confirm the outlet port currently selected by the selector 10 (step S34). If the answer in step S32 is Yes, when the controller 30 confirms that the outlet port selected by the selector 10 is not the outlet port 45 closest to the inlet port 44 (step S34: No), the controller 30 turns the selector 10 on. In order to reduce the effective length of the flow path 43 through which the reformed gas passes so as to control and suppress the generation of the aqueous reverse shift reaction and to generate a sufficient selective oxidation reaction, it is next to the outlet port currently selected. To an outlet port close to the inlet port 44 (step S35). As a result, the oxidation ability of the selective oxidation reactor 8 is lowered, so that the aqueous reverse shift reaction hardly occurs and the temperature rises. Then, the process of the controller 30 returns to step S32, and the controller 30 continues to monitor the temperature detected by the temperature sensor 34 and the temperature detected by the temperature sensor of the selected outlet port (step S32, step S33). If No in step S32, the process proceeds to the next step S33.

  On the other hand, if the time for which the reformed gas contacts the catalyst in the selective oxidation reactor 8 is shortened due to some cause, and the carbon monoxide is less than enough to react in the selective oxidation reactor 8, the carbon monoxide is sufficiently obtained. The selective oxidation reaction is not performed, and the carbon monoxide emitted from the selected outlet port cannot be sufficiently reduced. For this reason, since the amount of heat generated by the selective oxidation reaction is small in the vicinity of the selected outlet port, the difference between the temperature in the vicinity of the inlet port 44 and the temperature in the vicinity of the selected outlet port is less than the lower limit value of the normal temperature range A, that is, below the lower threshold value. become. If the controller 30 judges that (step S33: Yes), the controller 30 will confirm the outlet port currently selected by the selector 10 (step S36). When the controller 30 confirms that the outlet port selected by the selector 10 is not the outlet port 49 farthest from the inlet port 44 (step S36: No), the controller 30 controls the selector 10 to perform more selective oxidation reaction. In order to increase the effective length of the flow path 43 through which the reformed gas passes, the outlet port is switched to the outlet port far from the inlet port 44 next to the currently selected outlet port (step S37). As a result, the oxidation ability of the selective oxidation reactor 8 increases, so that carbon monoxide reacts sufficiently. Then, the process of the controller 30 returns to step S32, and the controller 30 continues to monitor the temperature detected by the temperature sensor 34 and the temperature detected by the temperature sensor of the selected outlet port (step S32, step S33).

  As described above, every time the difference between the temperature detected by the temperature sensor 34 and the temperature detected by the temperature sensor of the selected outlet port is outside the normal range, the outlet port selected by the selector 10 is switched (step S32: Yes). Step S34: No, Step S35, Step S33: Yes, Step S36: No, Step S37). When the difference between the temperature detected by the temperature sensor 34 and the temperature detected by the temperature sensor of the selected outlet port exceeds the upper threshold value, the outlet port selected by the selector 10 is the outlet port 45 closest to the inlet port 44. When the controller 30 confirms this and the outlet port selected by the selector 10 is the outlet port 45 that minimizes the effective length of the flow path 43 through which the reformed gas passes (step S34: Yes), The controller 30 stops the pump 3 and the air pumps 26 and 27 and supplies power to the heaters 5, 7, and 9 because the effective length of the flow path 43 cannot be further reduced to suppress the aqueous reverse shift reaction. Stop (step S38). At the same time, the controller 30 outputs an abnormal signal.

  When the difference between the temperature detected by the temperature sensor 34 and the temperature detected by the temperature sensor of the selected outlet port reaches a lower threshold value or less, the outlet port selected by the selector 10 is the outlet port 49 farthest from the inlet port 44. When the controller 30 confirms this and the outlet port selected by the selector 10 is the outlet port 49 that maximizes the effective length of the flow path 43 through which the reformed gas passes (step S36: Yes), The controller 30 stops the pump 3 and the air pumps 26 and 27 and stops the power supply to the heaters 5, 7, and 9 because the effective length of the flow path 43 is longer than that to promote the selective oxidation reaction (step S 38). ). At the same time, the controller 30 outputs an abnormal signal.

  According to this embodiment, since the port to be selected from the outlet ports 45 to 99 is set according to the difference between the temperature of the inlet port 44 and the temperature of the outlet port being selected, carbon monoxide is sufficiently removed. However, the production of carbon monoxide due to the aqueous reverse shift reaction can be suppressed. Therefore, removal of carbon monoxide in the selective oxidation reactor 8 can be performed stably.

[Fourth Embodiment]
In the fourth embodiment, as shown in FIG. 9, the temperature sensor is not provided in the anode 22, but the carbon monoxide concentration sensor 32 is provided in the middle of the path from the selector 10 to the anode 22. . This carbon monoxide concentration sensor 32 detects the concentration of carbon monoxide in the gas sent to the anode 22, converts it into an electrical signal, and outputs it to the controller 30. In the carbon monoxide concentration sensor 32, for example, a low-performance fuel cell that is easily poisoned is provided between the selective oxidation reactor 8 and the fuel cell 20. It can also be used as a sensor for detecting the carbon monoxide concentration.

Next, the operation of the fuel cell system 1 and the control operation of the controller 30 will be described with reference to FIG.
First, the controller 30 controls the selector 10, and the selector 10 selects the outlet port 45 closest to the inlet port 44 (step S41). Then, electric power is supplied to the heaters 5, 7 and 9 by the controller 30, and the vaporizer 4, the reformer 6 and the selective oxidation reactor 8 are heated to their appropriate temperature ranges. Next, when the controller 30 drives the pump 3 and the air pumps 25 and 27, the vaporizer 4, the reformer 6, the selective oxidation reactor 8, and the fuel cell 20 are activated. While the fuel cell 20 is generating power, the controller 30 controls the outputs of the heaters 5, 7, 9 and the pump 3 based on the temperatures detected by the heaters 5, 7, 9. Thereby, the vaporizer 4, the reformer 6, the selective oxidation reactor 8 and the like operate in a steady state.

  In addition, when the vaporizer 4, the reformer 6, and the selective oxidation reactor 8 are operating in a steady state, the controller 30 monitors the detected concentration by the carbon monoxide concentration sensor 32, and the detected concentration is an allowable value ( It is determined whether or not a predetermined threshold value has been exceeded (step S42).

  If the time for which the reactants contact the catalyst in the selective oxidation reactor 8 is appropriate, the aqueous reverse shift reaction does not occur and the carbon monoxide is sufficiently oxidized. Therefore, the carbon monoxide concentration in the gas discharged from the selective oxidation reactor 8 is very low. Therefore, since the detected concentration by the carbon monoxide concentration sensor 32 is less than the allowable value, the controller 30 continues to monitor the detected concentration by the carbon monoxide concentration sensor 32 (step S42: No, step S42).

  If the steady state balance is lost in the selective oxidation reactor 8 for some reason, the concentration of carbon monoxide in the gas sent from the selective oxidation reactor 8 to the anode 22 exceeds the allowable value. Then, the concentration detected by the carbon monoxide concentration sensor 32 exceeds a predetermined allowable value. If the controller 30 judges that (step S42: Yes), until the detected concentration by the carbon monoxide concentration sensor 32 is equal to or less than the allowable value (step S45: No, step S48: No), the controller 30 is controlled by the selector 10. The selected outlet ports are sequentially switched (step S44, step S46).

Specifically, when the concentration detected by the carbon monoxide concentration sensor 32 exceeds the allowable value (step S42: Yes), the controller 30 confirms the outlet port currently selected by the selector 10 (step S43). If it is confirmed that the outlet port selected by the selector 10 is the outlet port 49 farthest from the inlet port 44 (step S43: Yes), the flow path of the selective oxidation reactor 8 is too long and the aqueous reverse shift reaction is performed. Assuming that the carbon monoxide concentration has increased significantly, the process of the controller 30 proceeds to step S46, and the controller 30 determines that the outlet port selected by the selector 10 is not the outlet port 49 farthest from the inlet port 44. If confirmed (Step S43: No), the flow of the selective oxidation reactor 8 is too short, the selective oxidation reaction is considered not to proceed significantly, and the concentration of carbon monoxide does not decrease, and the processing of the controller 30 proceeds to Step S44. To do. In step S44, the controller 30 controls the selector 10 to switch to the outlet port far from the inlet port 44 next to the currently selected outlet port (step S44). If the detected concentration by the carbon monoxide concentration sensor 32 still exceeds the allowable value (step S45: Yes), the process of the controller 30 returns to step S43, and the detected concentration by the carbon monoxide concentration sensor 32 is less than the allowable value. (Step S45: No), the process of the controller 30 returns to Step S42. On the other hand, in step S46, when it is confirmed that the outlet port selected by the selector 10 is the outlet port 49 farthest from the inlet port 44 (step S43: Yes), the controller 30 controls the selector 10 to Next to the outlet port being selected, the outlet port 44 is switched to the nearest outlet port (step S46). If the detected concentration detected by the carbon monoxide concentration sensor 32 still exceeds the allowable value (step S48: Yes), the process of the controller 30 returns to step S46, and the detected concentration detected by the carbon monoxide concentration sensor 32 is less than the allowable value. (Step S48: No), the process of the controller 30 returns to Step S42. When steps S46 to S48 are repeated, when it is confirmed that the outlet port selected by the selector 10 is the outlet port 45 closest to the inlet port 44 (step S47: Yes), the carbon monoxide concentration If the concentration detected by the sensor 32 exceeds the allowable value (step S49: Yes), the controller 30 stops the pump 3 and the air pumps 26, 27 and stops the power supply to the heaters 5, 7, 9 (step S50). . At the same time, the controller 30 outputs an abnormal signal. If the detected concentration by the carbon monoxide concentration sensor 32 does not exceed the allowable value (step S49: No), the carbon monoxide contained in the reformed gas discharged from the selective oxidation reactor 8 covers the fuel cell 20. It is determined that there is no longer a risk of poisoning, and the process returns to step S42 after a predetermined time that is regarded as returning to the steady state.
In FIG. 10, even if the flow rate of the reformed gas is too high and the exhaust gas is switched to the outlet port 49 having the longest flow path 43 and discharged, the selective oxidation of carbon monoxide is still insufficient and the carbon monoxide If the concentration is too high (S42: Yes, S43: Yes), the outlet port 49 that is currently selected is switched from the inlet port 44 next to the outlet port 48 that is next (step S46), and the inlet port 44 is sequentially approached. Switching to the outlet port (steps S46, S47: No, S48: No), and finally switching to the outlet port 45 that becomes the shortest route of the flow path 43, and the concentration detected by the carbon monoxide concentration sensor 32 exceeds the allowable value. (Step S49: Yes), eventually, the controller 30 is connected to the pump 3 and Stops the Aponpu 27, it means to stop the power supply of the heater 5,7,9 (step S50), does not catalysts of the fuel cell 20 is significantly poisoned by carbon monoxide.

  According to the present embodiment, the port to be selected from the outlet ports 45 to 99 is set according to the concentration of carbon monoxide sent to the anode 22, so that the aqueous reverse shift reaction is performed while sufficiently removing carbon monoxide. The generation of carbon monoxide due to can be suppressed. Therefore, removal of carbon monoxide in the selective oxidation reactor 8 can be performed stably.

1 is a block diagram illustrating a configuration of a fuel cell system according to a first embodiment of the present invention. It is the schematic which showed the cross section of the selective oxidation reactor, and the selector. It is the cross-sectional view which showed the selective oxidation reactor. It is the flowchart which showed the flow of the process by the controller in 1st Embodiment. It is the block diagram which showed the structure of the fuel cell system in 2nd Embodiment of this invention. It is the flowchart which showed the flow of the process by the controller in 2nd Embodiment. It is the block diagram which showed the structure of the fuel cell system in 3rd Embodiment of this invention. It is the flowchart which showed the flow of the process by the controller in 3rd Embodiment. It is the block diagram which showed the structure of the fuel cell system in 4th Embodiment of this invention. It is the flowchart which showed the flow of the process by the controller in 4th Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fuel cell system 6 Reformer 8 Selective oxidation reactor 10 Selector 20 Fuel cell 21 Electrolyte membrane 22 Anode 23 Cathode 24 Temperature sensor 30 Controller 31 Oxygen concentration sensor 32 Carbon monoxide concentration sensor 34-39 Temperature sensor 43 Channel 44 Inlet port 45 Outlet port 50 Catalyst

Claims (2)

A reformer that reforms fuel and water into hydrogen;
An inlet port for taking in a product from the reformer, a flow path leading to the inlet port, a catalyst provided in the flow path, and a plurality of paths leading to the flow path at different positions to the inlet port A selective oxidation reactor having an outlet port;
A fuel cell having an anode, a cathode, and an electrolyte membrane provided therebetween;
A selector that selects any of the plurality of outlet ports and communicates with the anode;
A controller for controlling the selector;
A temperature detector for detecting the temperature of the anode;
With
Fuel cell system the controller is characterized that you control the selector based on the temperature detected by the temperature detector. The controller switches an outlet port to be selected from the plurality of outlet ports to an outlet port far from the inlet port next to the selected outlet port each time the temperature detected by the temperature detector reaches a predetermined threshold value. The fuel cell system according to claim 1 , wherein the selector is configured to perform the following.

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