JP5228751B2 - Reaction system - Google Patents

Description

  The present invention relates to a reaction system, and more particularly to a reaction system for producing hydrogen.

  In recent years, as a clean power source with high energy conversion efficiency, fuel cells that generate electric energy by electrochemical reaction of hydrogen have begun to be applied to automobiles, portable electronic devices, and the like.

Since hydrogen is a gas at room temperature, it is difficult to handle and store. For this reason, the stored hydrogen is not supplied to the fuel cell, but hydrogen is obtained by reacting alcohol such as methanol or hydrocarbon. Specifically, the vaporized fuel is mixed with water vapor and reacted in a reformer to obtain a product gas containing hydrogen. Since the reaction channel in the reformer is provided with a catalyst, the reforming reaction can easily proceed by their action (see Patent Document 1).
Further, since the produced gas contains carbon monoxide which is harmful to the fuel cell, only the carbon monoxide is selectively removed by the preferential oxidation reactor. Since a catalyst is provided in the reaction channel of the preferential oxidation reactor, carbon monoxide can be removed by preferentially oxidizing carbon monoxide.
JP 2001-148254 A

In order to improve the reforming efficiency per unit volume of fuel in the reformer, it is conceivable that the molar ratio of water to methanol in the methanol aqueous solution of the fuel is close to the stoichiometric ratio of 1: 1. However, this makes it easier for carbonaceous materials to deposit on the catalyst surface in the main reaction zone of the reformer. As a result, the reforming performance of the catalyst is lowered, and the amount of hydrogen generation decreases with time.
In the carbon monoxide remover, carbon monoxide can be removed by oxidizing with oxygen in the air. However, if a large amount of air is introduced relative to carbon monoxide, the generated hydrogen is also oxidized in a large amount by oxygen. Therefore, the amount of air to be introduced is preferably as small as possible. However, since the carbon monoxide oxidation catalyst has a strong ability to adsorb carbon monoxide, the surface of the catalyst is easily covered with carbon monoxide when the amount of air is reduced. As a result, the performance of the coated catalyst decreases, and the carbon monoxide removal rate decreases with time. In order to sufficiently remove carbon monoxide in such a state, it is necessary to supply excess oxygen, resulting in a problem that a large amount of the reformed hydrogen is oxidized.

That is, when a catalyst deterioration substance or a catalyst poisoning substance flows through the inside of a catalyst reactor such as a reformer or a carbon monoxide remover, the catalyst inside the catalyst reactor gradually deteriorates. Then, it was not possible to carry out the reaction continuously for a long time in the catalytic reactor.
For this reason, in order to restore the performance of the catalyst, the operation of the power generation system must be stopped periodically, and the deposited carbonaceous material and adsorbed carbon monoxide must be removed. It was difficult to supply.

  Accordingly, an object of the present invention is to enable a catalytic reaction to be continuously performed in a catalytic reactor.

In order to solve the above problems, according to the present invention, two inlets, a reaction channel provided from one to the other of the two inlets, and a catalyst provided in the reaction channel, A catalytic reactor which is a reformer having an upstream processing device which is a vaporizer for processing the fuel and sending the processed product from the outlet to the catalytic reactor, and an inlet for the product passed through the catalytic reactor A downstream reactor that is a carbon monoxide remover that reacts with the product taken in, and one of the two inlets is connected to the outlet of the upstream processor, and the other is connected to the downstream reactor. a first state in which the connection to the inlet, and the second state and switches to selectively switch unit connected one to the inlet of the downstream reactor while connecting the other to the outlet of the upstream processor, wherein One side of two doorways A first temperature detection unit that detects a temperature on one side thereof, a second temperature detection unit that is provided on the other side of the two entrances and detects a temperature on the other side, and the first temperature detection unit And a control unit that controls the direction switching unit based on the temperature detected by the second temperature detection unit and a second temperature detection unit .

Preferably, the control unit obtains a difference between a temperature detected by the first temperature detection unit and a temperature detected by the second temperature detection unit, and when the obtained difference is equal to or less than a predetermined threshold, Switch from the first state to the second state or vice versa.
Preferably, the control unit obtains a difference between a temperature detected by the first temperature detecting unit and a temperature detected by the second temperature detecting unit, and when the obtained difference exceeds a predetermined threshold, The first state or the second state is maintained .

  According to the present invention, the flow of the reactants in the catalytic reactor is reversed by switching the switching unit from the first state to the second state or vice versa. As a result, the catalyst in the vicinity of one of the inlets and outlets that has not contributed much to the reaction and has not deteriorated in performance is used for the reaction. Further, the catalyst whose performance has been reduced recovers its performance while moving away from the main reaction zone. Therefore, the reaction can be continuously performed by repeatedly switching the switching unit.

  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 power generation / reaction system 100 according to the first embodiment of the present invention. The power generation / reaction system 100 is mounted on a portable electronic device such as a notebook PC, a PDA, an electronic notebook, a digital camera, a mobile phone, a wristwatch, or a game device. Among the components shown in FIG. 1, the fuel container 1 is detachable from the electronic device, and the other components are built in the electronic device. When the fuel container 1 is mounted on an electronic device, the fuel container 1 and the fuel pump 2 are connected.

  The power generation / reaction system 100 includes a fuel container 1, a fuel pump 2, a vaporizer 3, a direction switching valve 10, a reformer 4, a carbon monoxide remover 5, a fuel cell 7, a catalytic combustor 8, a hydrogen combustor 9, and the like. Is provided.

  The fuel container 1 stores liquid fuel (for example, methanol, ethanol, dimethyl ether) and water in a mixed state or in a separate state.

  The fuel pump 2 sucks up a liquid mixture of liquid fuel and water from the fuel container 1 and sends the sucked up liquid mixture to the vaporizer 3. The fuel pump 2 is an electrically driven pump.

  The air pump 6 supplies external air to the carbon monoxide remover 5, the cathode 72 of the fuel cell 7, the catalytic combustor 8, and the hydrogen combustor 9. The air pump 6 is an electrically driven pump.

  The vaporizer 3 is an upstream processor provided on the upstream side of the reformer 4. The vaporizer 3 vaporizes the fuel as a fuel treatment. Specifically, the vaporizer 3 vaporizes a liquid mixture of liquid fuel and water sent from the fuel pump 2. The vaporizer 3 is provided with a heater 31 made of an electric heating material, and the mixed solution sent from the fuel pump 2 to the vaporizer 3 is vaporized by the heat of the heater 31. The mixture of water and fuel vaporized in the vaporizer 3 is sent to the reformer 4 via the direction switching valve 10 which is a switching unit.

The reformer 4 reacts the water vaporized by the vaporizer 3 and fuel to generate hydrogen gas or the like. Further, a slight amount of carbon monoxide is generated in the reformer 4. When the fuel in the fuel container 1 is methanol, chemical reactions such as (1) and (2) occur. Since the reforming reaction performed in the reformer 4 is an endothermic reaction, the reformer 4 is heated by the heater 43.
CH ₃ OH + H ₂ O → 3H ₂ + CO ₂ (1)
H ₂ + CO ₂ → H ₂ O + CO (2)

  The product gas (mixture of hydrogen gas, carbon dioxide, carbon monoxide, etc.) generated by the reformer 4 is sent to the carbon monoxide remover 5 via the direction switching valve 10.

  The carbon monoxide remover 5 is a downstream reactor provided on the downstream side of the reformer 4. The carbon monoxide remover 5 selectively removes carbon monoxide contained in the product gas produced by the reformer 4. The carbon monoxide remover 5 has a flow path 51b, and a selective oxidation catalyst (for example, a Pt catalyst) is supported on the wall surface of the flow path 51b.

The product gas generated by the reformer 4 is mixed with the air sent from the air pump 6 and flows through the flow path 51 b of the carbon monoxide remover 5. Carbon monoxide is preferentially oxidized by the selective oxidation catalyst as shown in the following formula (3). This produces carbon dioxide and removes carbon monoxide. The product gas from which the carbon monoxide has been removed is sent to the anode 71 of the fuel cell 7.
2CO + O ₂ → 2CO ₂ (3)

  The fuel cell 7 includes an anode 71, a cathode 72, and an electrolyte membrane 73 sandwiched between the anode 71 and the cathode 72. The product gas sent from the carbon monoxide remover 5 is sent to the anode 71 of the fuel cell 7, and external air is sent to the cathode 72 by the air pump 6. The hydrogen supplied to the anode 71 undergoes an electrochemical reaction with oxygen in the air supplied to the cathode 72 via the electrolyte membrane 73, thereby generating electric power between the anode 71 and the cathode 72.

The electrolyte membrane 73 is a solid polymer electrolyte membrane. Therefore, a reaction such as the following formula (4) occurs at the anode 71, hydrogen ions generated at the anode 71 pass through the electrolyte membrane 73, and a reaction such as the following formula (5) occurs at the cathode 72.
H ₂ → 2H ⁺ + 2e ⁻ (4)
2H ⁺ + 1 / 2O ₂ + 2e ⁻ → H ₂ O (5)

  Electric power generated between the anode 71 and the cathode 72 of the fuel cell 7 is supplied to the DC / DC converter 20. The DC / DC converter 20 is for supplying electricity generated by the fuel cell 7 to an appropriate circuit after being converted into an appropriate voltage. Water is generated at the cathode 72 and is collected in the fuel container 1 or sent from the cathode 72 together with air that has not contributed to the reaction as water vapor.

  The catalytic combustor 8 heats the reformer 4 and the carbon monoxide remover 5 by burning the hydrogen gas remaining without electrochemical reaction at the anode 71 of the fuel cell 7. A flow path is formed inside the catalytic combustor 8, and a combustion catalyst (for example, a Pt catalyst) is supported on the wall surface of the flow path. Hydrogen gas or the like sent from the anode 71 to the catalyst combustor 8 flows through the flow path of the catalyst combustor 8 in a state of being mixed with external air introduced from the air pump 6, and the hydrogen gas or the like is heated by the heater 81. The Of the air-fuel mixture flowing through the flow path of the catalytic combustor 8, hydrogen is burned by the combustion catalyst, thereby generating combustion heat. The combustion heat generated in the catalytic combustor 8 is propagated to the reformer 4 and the carbon monoxide remover 5 and used to promote the reforming reaction in the reformer 4 and the selective oxidation reaction of the carbon monoxide remover 5. The catalytic combustor 8 is set not to burn all the hydrogen discharged from the anode 71 of the fuel cell 7 so that the reformer 4 and the carbon monoxide remover 5 are not overheated by the combustion heat.

  The hydrogen combustor 9 is combusted to a concentration that does not cause a problem even if a small amount of hydrogen remaining after the combustion of the catalytic combustor 8 is discharged to the outside. The air-fuel mixture that has passed through the catalytic combustor 8 is sent to the hydrogen combustor 9, and external air is further supplied to the hydrogen combustor 9 by the air pump 6. A flow path is also formed inside the hydrogen combustor 9, and a combustion catalyst (for example, a Pt catalyst) is supported on the wall surface of the flow path. The air-fuel mixture sent from the catalyst combustor 8 to the hydrogen combustor 9 is mixed with air and flows through the flow path of the hydrogen combustor 9. Thereby, a very small amount of hydrogen contained in the air-fuel mixture sent from the catalytic combustor 8 is removed as water.

  The reformer 4, the catalytic combustor 8, and the carbon monoxide remover 5 are accommodated in a heat insulating package. The inside of the heat insulation package is in a vacuum state of less than 1 Pa, and the heat inside the heat insulation package is difficult to dissipate to the outside. In addition, the direction switching valve 10 may be accommodated in the heat insulation package, or may be installed outside the heat insulation package.

  Next, the reformer 4 will be specifically described. 2 is a top view of the reformer 4, FIG. 3 is a bottom view of the reformer 4, and FIG. 4 is a cross-sectional view of the reformer 4. The reformer 4 is configured by bonding a silicon substrate 41 and a glass substrate 42 together. A heater 43, which is a thin-film electric resistance heating element, is formed on the surface of the silicon substrate 41 (the surface opposite to the bonding surface), and a meandering groove-shaped reaction channel is formed on the back surface (bonding surface) of the silicon substrate 41. 41b is formed. A reforming catalyst (for example, a Cu / ZnO-based catalyst) 41c is supported on the wall surface of the reaction channel 41b. A glass substrate 42 is bonded to the back surface of the silicon substrate 41. The glass substrate 42 is provided with entrances 4a and 4b at positions overlapping with both ends of the reaction channel 41b. For this reason, when gas is sent from the inlet / outlet 4a, it passes through the reaction channel 41b and exits from the inlet / outlet 4b. Of course, the reverse is also possible. A first temperature sensor 44a, which is a first temperature detection unit, is attached to the side of the entrance / exit 4a, and a second temperature sensor 44b, which is a second temperature detection unit, is attached to the side of the entrance / exit 4b. The temperatures near both ends are detected by the temperature sensors 44a and 44b, respectively, and converted into electrical signals. The first temperature sensor 44a and the second temperature sensor 44b may be a thermistor. The thermistor preferably has a laminated structure of gold (Au) and a refractory metal base film such as tungsten interposed to prevent the gold from thermally diffusing into the silicon substrate 41. At this time, in order to sufficiently function as a thermistor, the thickness of each layer is set so that the resistance of gold becomes 1/10 or less of the resistance of the refractory metal base film. In this case, the heaters 43 may be collectively formed of the same metal film as the first temperature sensor 44a and the second temperature sensor 44b.

  Next, the direction switching valve 10 will be described. The direction switching valve 10 is a direction switching valve in which the number of ports is four and the number of switching positions is two. Specifically, the direction switching valve 10 is configured as shown in FIGS. 5 and 6 are schematic views showing the reformer 4 together with the cross section of the direction switching valve 10. The direction switching valve 10 includes a cylinder 10e, a valve body 11, ports 10a to 10d, an actuator, and the like. Ports 10a to 10d are formed in the cylinder 10e. The valve body 11 is accommodated inside the cylinder 10e so as to divide the internal space of the cylinder 10e into two regions. A part of the valve body 11 is inscribed in the cylinder 10e. The valve body 11 is rotated with respect to the cylinder 10e by an electric actuator. When the valve body 11 is located as shown in FIG. 5, one of the two regions partitioned by the valve body 11 communicates with the ports 10a and 10b, and the other communicates with the ports 10c and 10d. On the other hand, when the valve body 11 is in a position as shown in FIG. 6, one of the two regions partitioned by the valve body 11 communicates with the ports 10a and 10c, and the other communicates with the ports 10b and 10d. Yes. Hereinafter, the state of FIG. 5 is referred to as a first state, and the state of FIG. 6 is referred to as a second state.

  For example, during the initial reforming, as shown in FIGS. 1 and 5, the port 10 a communicates with the outlet 3 b of the vaporizer 3, the port 10 b communicates with the inlet / outlet 4 a of the reformer 4, and the port 10 c connects with the inlet / outlet of the reformer 4. When the port 10d is in the first state leading to the inlet 5a of the carbon monoxide remover 5, the outlet 3b of the vaporizer 3 is connected to the inlet / outlet 4a of the reformer 4 by the direction switching valve 10. In addition to being connected, the inlet / outlet 4 b of the reformer 4 is connected to the inlet 5 a of the carbon monoxide remover 5 by the direction switching valve 10. On the other hand, if it is considered that the reforming reaction rate due to the catalyst in the vicinity of the inlet / outlet 4a of the reformer 4 has decreased after the initial reforming time, the direction switching valve 10 is set to the second state as shown in FIG. The outlet 3 b of the vaporizer 3 is connected to the inlet / outlet 4 b of the reformer 4 by the direction switching valve 10, and the inlet / outlet 4 a of the reformer 4 is connected to the inlet 5 a of the carbon monoxide remover 5.

  FIG. 7 is a block diagram showing a circuit configuration of the power generation / reaction system 100. The control unit 30 is a microcomputer. That is, the control unit 30 includes a CPU, a RAM, a ROM, and the like. The control unit 30 controls the fuel pump 2, the air pump 6, the heater 31 of the vaporizer 3, the heater 43 of the reformer 4, the direction switching valve 10, and the like according to a program stored in the ROM.

The temperature detected by the first temperature sensor 44 a and the temperature detected by the second temperature sensor 44 b are output to the control unit 30.
The control unit 30 has a function of controlling the direction switching valve 10 based on temperatures detected by the first temperature sensor 44a and the second temperature sensor 44b by a program stored in the ROM. Specifically, the control unit 30 moves from the detected temperature t2 on the side connected to the inlet 5a of the carbon monoxide remover 5 to the outlet 3b of the vaporizer 3 among the first temperature sensor 44a and the second temperature sensor 44b. It has a subtraction function for obtaining a value obtained by subtracting the detected temperature t1 on the connected side. The control unit 30 has a comparison function that compares the obtained difference with a predetermined threshold value and determines whether the obtained difference exceeds the predetermined threshold value. Here, if the catalyst of the reformer 4 is functioning normally, the reforming endothermic reaction rate is on the side of the first temperature sensor 44a and the second temperature sensor 44b connected to the outlet 3b of the vaporizer 3. Therefore, the detected temperature is lower than that on the side connected to the inlet 5a of the carbon monoxide remover 5. Therefore, t2−t1 is a positive value, and when the abnormal operation threshold temperature is T, t2−t1> T, and the control unit 30 determines that the catalyst is in a good state. On the other hand, when the catalyst of the reformer 4 on the side connected to the outlet 3b of the vaporizer 3 deteriorates, it is connected to the outlet 3b of the vaporizer 3 out of the first temperature sensor 44a and the second temperature sensor 44b. Since the endothermic reaction rate is low on the side where the gas is present, the temperature t1 increases, and on the side connected to the inlet 5a of the carbon monoxide remover 5, the concentration of the raw material that enters unreacted increases and the endothermic reaction increases. Since t2 becomes low, t2−t1 ≦ T, and the control unit 30 determines that the state of the catalyst is bad. When it is determined that the obtained difference (t2−t1) exceeds the predetermined threshold T, the control unit 30 has a maintenance function for maintaining the state of the direction switching valve 10 in the current state (first state or second state). Have. On the other hand, if the controller 30 determines that the obtained difference (t2−t1) is equal to or less than the predetermined threshold T, the switching function that switches the state of the direction switching valve 10 from the first state to the second state or vice versa. Have Note that these functions may be realized not by a program but by a logic circuit. For example, the subtraction function is realized by a subtracter, the comparison function is realized by a comparator, and the maintenance function and the switching function are realized by a switching circuit.

Next, the flow of processing by the control unit 30 and the operation of the power generation / reaction system 100 associated therewith will be described.
First, the control unit 30 supplies power to the heater 31 and the heater 43 to cause the heater 31 and the heater 43 to generate heat. Thereby, the vaporizer 3 and the reformer 4 are heated.
The carbon monoxide remover 5 is also provided with a heater. When the temperature of the carbon monoxide remover 5 is room temperature, the carbon monoxide remover 5 is heated by the heater.
Next, the control unit 30 operates the air pump 6. As a result, air is supplied to the carbon monoxide remover 5, the cathode 72 of the fuel cell 7, the catalytic combustor 8, and the hydrogen combustor 9.
Next, the control part 30 makes the direction switching valve 40 a 1st state.

  Next, the control unit 30 operates the fuel pump 2. Thereby, the fuel and water in the fuel container 1 are sent to the vaporizer 3, and the fuel and water are vaporized in the vaporizer 3. The vaporized fuel / water mixture is delivered from the vaporizer 3. The vaporized water and fuel sent from the outlet 3b of the vaporizer 3 are the catalyst that the control unit 30 has determined to be better due to the temperature difference between the first temperature sensor 44a and the second temperature sensor 44b in the previous operation. In order to enter the reformer 4 from a certain side, for example, it enters the cylinder 10e from the port 10a, exits from the port 10b through the cylinder 10e, and enters the reaction flow path 41b of the reformer 4 from, for example, the inlet / outlet 4a. The fuel / water mixture reacts with the reforming catalyst 41c while flowing through the reaction channel 41b. The reaction between the fuel and water occurs near the upstream inlet / outlet 4a in the reaction channel 41b and does not occur near the downstream inlet / outlet 4b. The product gas generated through the reforming reaction exits from the inlet / outlet 4b, enters the cylinder 10e from the port 10c, exits from the port 10d through the cylinder 10e, and is sent to the inlet 5a of the carbon monoxide remover 5. Of the product gas introduced into the carbon monoxide remover 5, carbon monoxide is removed by a selective oxidation reaction. Then, an electrochemical reaction between hydrogen and oxygen occurs in the fuel cell 7, unreacted hydrogen burns in the catalytic combustor 8, and residual hydrogen burns and is removed in the hydrogen combustor 9. In this way, exhaust gas is discharged from the hydrogen combustor 9.

  As described above, while the fuel pump 2 and the air pump 6 are operating, the control unit 30 executes the routine shown in FIG. 8 every time a fixed time elapses. When the routine shown in FIG. 8 is started, the control unit 30 detects the detected temperature t1 on the side of the first temperature sensor 44a and the second temperature sensor 44b connected to the outlet 3b of the vaporizer 3 (in FIG. 5). The detected temperature of the first temperature sensor 44a, and in the case of FIG. 6, the detected temperature of the second temperature sensor 44b) and the detected temperature t2 on the side connected to the inlet 5a of the carbon monoxide remover 5 (FIG. 5). In this case, the detected temperature of the second temperature sensor 44b is input. In the case of FIG. 6, the detected temperature of the first temperature sensor 44a is input (step S1). The control unit 30 compares a value (t2−t1) obtained by subtracting the detected temperature t1 from the detected temperature t2 with a predetermined threshold T. (Step S2). As a result of the comparison, if the controller 30 recognizes that the temperature difference (t2−t1) exceeds the predetermined threshold T (step S2: Yes), the process returns to step S1 again. Therefore, the state of the direction switching valve 10 is kept in the current state. On the other hand, when the controller 30 recognizes that the temperature difference (t2−t1) is equal to or less than the predetermined threshold T (step S2: No), the controller 30 operates the actuator of the direction switching valve 10 to operate the valve. By rotating the body 11, the state of the direction switching valve 10 is switched from the first state to the second state or vice versa (step S3), and the process returns to step S1. If the detected temperatures at the first temperature sensor 44a and the second temperature sensor 44b before switching are t1 and t2, respectively, the detected temperatures at the first temperature sensor 44a and the second temperature sensor 44b after switching are t2 and t1, respectively. It becomes.

  Here, as described above, most of the reforming of the fuel is performed in the upstream portion of the reaction flow path 41 b of the reformer 4. In the main reaction zone where most of the reaction is performed, if the reforming is continued for a long time, the carbonaceous material is gradually deposited on the surface of the reforming catalyst 41c, and the reforming performance of the reforming catalyst 41c is lowered. . Then, the main reaction zone gradually moves from the vicinity of the inlet of the reaction channel 41b toward the back of the reaction channel 41b where no carbonaceous material is deposited.

  FIG. 9 shows the temperature distribution in the reaction channel 41b when the reforming reaction is occurring in the reaction channel 41b. The vertical axis indicates the temperature, the horizontal axis indicates the distance from the inlet / outlet 4a, and x1 indicates the first. The installation position of the temperature sensor 44a and x2 is the installation position of the second temperature sensor 44b. Since the reforming reaction is an endothermic reaction, the temperature in the main reaction zone where the reforming reaction is actively performed is lower than the surroundings. In a state where no carbonaceous material is deposited yet, since the main reaction zone and x1 are close to each other, the detected temperature tx1 at x1 is t1, and the detected temperature tx2 at x2 is t2, (however, t1 <T2) and their difference (t2-t1) exceeds a predetermined threshold T. Therefore, even if the control unit 30 executes the process of FIG. 8, the difference between the detected temperatures tx1 and tx2 also exceeds the predetermined threshold T (step S2: Yes), so the control unit 30 is in the state of the direction switching valve 10 The direction switching valve 10 is maintained in the first state without switching.

Thereafter, when the carbonaceous material is deposited and the reaction does not occur in the vicinity of x1, the main reaction zone moves from the upstream portion to the downstream portion of the reaction channel 41b, and the temperature distribution also changes. The movement of the main reaction zone, the temperature distribution is shown by the broken line in FIG. 9, the temperature in the x1 rises from tx1 to _tx ^{1 *,} the temperature at x2 is almost constant at t2 (where, tx1 <tx1 ^* <T2). As a result, the difference (t2−t1) between the temperature at x1 and the temperature at x2 becomes smaller. Therefore, at a certain point in time, when the difference (t2−t1) between the temperature at x1 and the temperature at x2 is equal to or less than the predetermined threshold T (step S2: No), the control unit 30 changes the state of the direction switching valve 10 to the first state. The state is switched to the second state (step S3). 6 and 10, the outlet 3b of the vaporizer 3 and the inlet / outlet 4b of the reformer 4 are connected, and the inlet / outlet 4a of the reformer and the inlet 5a of the carbon monoxide remover 5 are connected. In the direction switching valve 10, vaporized water and fuel that have entered the cylinder 10e from the port 10a escape from the port 10c, and enter the reaction flow path 41b of the reformer 4 from the inlet / outlet 4b. The product gas generated through the reforming reaction exits from the inlet / outlet 4a, enters the cylinder 10e from the port 10b, exits from the port 10d through the cylinder 10e, and is sent to the inlet 5a of the carbon monoxide remover 5.

  Therefore, after the rotation of the valve body 11, the fuel / water mixture vaporized in the vaporizer 3 flows in the reformer 4 in the opposite direction. That is, the air-fuel mixture enters from the entrance / exit 4b, which has been on the exit side, and exits to the entrance / exit 4a. Since the reforming catalyst in the vicinity of the entrance / exit 4b has hardly contributed to the reaction so far, almost no carbonaceous material is deposited at this point. Therefore, the vicinity of the entrance / exit 4b becomes a new main reaction zone, and the reforming capacity becomes almost the first level.

  Note that the temperatures detected by the first temperature sensor 44a and the second temperature sensor 44b also change. Since the vicinity of the entrance / exit 4b becomes a new main reaction zone, the temperature detected by the second temperature sensor 44b decreases. On the other hand, the temperature detected by the first temperature sensor 44a installed in the vicinity of the entrance / exit 4a that is no longer the main reaction zone increases.

  Further, the hydrogen generated in the new main reaction zone passes over the carbonaceous material deposited on the reforming catalyst near the inlet / outlet 4b and is sent from the inlet / outlet 4a to the carbon monoxide remover 5. At this time, the deposited carbonaceous material reacts with a part of hydrogen to become hydrocarbons and desorb. If the generation of hydrogen is continued, the carbonaceous material deposited at a certain time is removed. It should be noted that hydrogen contained in the hydrogen gas or the like sent to the carbon monoxide remover 5 is slightly reduced by combining the deposited carbonaceous material with hydrogen, which affects the power generation of the fuel cell 7. Don't do it.

  If the state in which the flow in the reformer 4 is reversed continues for a while, the carbonaceous material starts to be deposited near the inlet / outlet 4b. Then, the temperature t1 near the location x2 where the second temperature sensor 44b is installed rises, and approaches the temperature t2 near x1. When the difference between the temperature t2 and the temperature t1 (t2−t1) is equal to or less than the predetermined threshold T (step S2: No), the control unit 30 changes the state of the direction switching valve 10 from the second state to the first state. Switching (step S3). Under the control of the control unit 30, the flow direction in the reformer 4 is reversed again to be in the state shown in FIGS.

  As described above, the reforming is performed by the reforming catalyst 41c in a state where the carbonaceous material is relatively less deposited in the vicinity of one of the entrances 4a and 4b, and the performance of the reforming catalyst 41c whose performance is degraded is simultaneously near the other. Recovery is done. When the reforming progresses and the carbonaceous material starts to accumulate on the reforming catalyst 41c, the flow of the reaction channel 41b is switched in the reverse direction. By repeating this operation, it is possible to continuously generate hydrogen while always maintaining high reforming performance.

When the electrolyte membrane 73 of the fuel cell 7 is a solid oxide electrolyte membrane and the fuel cell 7 is a solid oxide electrolyte membrane fuel cell, the carbon monoxide remover 5 is not provided. In this case, the downstream reactor is the fuel cell 7, and the port 10 d of the direction switching valve 10 is connected to the inlet 7 a of the anode 71.
Moreover, in the said embodiment, although the direction switching valve 10 was a valve body rotation type, it may have a some on-off valve.

[Second Embodiment]
FIG. 11 is a block diagram showing a power generation / reaction system 200 according to the second embodiment of the present invention. The characteristics of the individual components of the power generation / reaction system 200 are the same as those used in the first embodiment. However, in this embodiment, the upstream processor is the reformer 104, the catalytic reactor is the carbon monoxide remover 105, and the downstream reactor is the fuel cell 107.

  Along with this, the connection location of the direction switching valve 110 is also changed. That is, among the four ports, the port 110a is the outlet 104b of the reformer 104, the port 110b is the inlet / outlet port 105a of the carbon monoxide remover 105, the port 110c is the inlet / outlet port 105b of the carbon monoxide remover, and the port 110d is The fuel cell 107 is connected to the inlet 171 a of the anode 171. When the direction switching valve 110 is in the first state, the outlet 104b of the reformer 104 leads to the inlet / outlet 105a of the carbon monoxide remover 105, and the inlet / outlet 105b of the carbon monoxide remover 105 is connected to the inlet of the anode 171. 171a (see FIG. 11). On the other hand, when the direction switching valve 110 is in the second state, the outlet 104b of the reformer 104 leads to the inlet / outlet 105b of the carbon monoxide remover 105, and the inlet / outlet 105a of the carbon monoxide remover 105 is connected to the anode 171. Leading to the inlet 171a (see FIG. 15).

  The air taken in from the outside by the air pump 106 is not sent directly to the carbon monoxide remover 105 but is sent to the port 110 a of the direction switching valve 110. The outlet of the vaporizer 103 is connected to the inlet of the reformer 104.

  FIG. 12 is a cross-sectional view showing the carbon monoxide remover 105. In this carbon monoxide remover 105, two substrates 151 and 152 are joined, and a reaction channel 151 b is provided in a recessed state on the joining surface of the substrate 151. The flow path 151 is provided in a meandering state. Entrances 105 a and 105 b are formed in the substrate 152, and the entrance 105 a communicates with one end of the channel 151, and the entrance 105 b communicates with the other end of the channel 151. A selective oxidation catalyst (for example, Pt catalyst) 151c is supported on the wall surface of the flow path 151. A thin film heater 43 is formed on the upper surface of the substrate 151.

  FIG. 13 is a block diagram showing a circuit configuration of the power generation / reaction system 200. As in the first embodiment, the control unit 130 is a microcomputer having a CPU, RAM, ROM, and the like. The control unit 130 controls the fuel pump 102, the air pump 106, the heater 131 of the vaporizer 103, the heater 143 of the reformer 104, the direction switching valve 110, and the like according to a program stored in the ROM.

  The DC / DC converter 120 also serves as a power detection unit that detects the output power of the fuel cell 107. The output power detected by the DC / DC converter 120 is converted into a signal and output to the control unit 130. The control unit 130 controls the direction switching valve 110 based on a signal from the DC / DC converter 120.

Next, the flow of processing by the control unit 130 and the operation of the power generation / reaction system 200 associated therewith will be described using the flowchart of FIG.
First, when the control unit 130 causes the heater 131, the heater 143, and the heater 153 to generate heat, the vaporizer 103, the reformer 104, and the carbon monoxide remover 105 are heated. When the carbon monoxide remover 105 is heated to a predetermined temperature, heating by the heater 153 is stopped.
Next, the control unit 130 operates the air pump 106. As a result, air is supplied to the cathode 172, the catalytic combustor 108, and the hydrogen combustor 109 of the fuel cell 107.
Next, the control unit 130 sets the direction switching valve 110 to the first state. Then, the outlet 104b of the reformer 104b is connected to the inlet / outlet 105a of the carbon monoxide remover 105 by the direction switching valve 110, and the inlet / outlet 105b of the carbon monoxide remover 105 is connected to the inlet 171a of the anode 171 by the direction switching valve 110 ( FIG. 11).

  Next, the control unit 130 operates the fuel pump 102. As a result, the fuel and water in the fuel container 101 are sent to the vaporizer 103, and the fuel / water mixture vaporized by the vaporizer 103 is sent to the reformer 104. The mixture of fuel and water reacts with a catalyst inside the reformer 104 to generate hydrogen, carbon dioxide, carbon monoxide and the like. The product gas generated in the reformer 104 exits from the outlet 104b of the reformer 104 and is sent to the carbon monoxide remover 105 via the ports 110a and 110b of the direction switching valve 110. Air is also sent to the carbon monoxide remover 105. A mixture of product gas and air flows into the reaction channel 151b from the inlet / outlet port 105a. When the product gas flows through the reaction channel 151b, carbon monoxide in the product gas is preferentially oxidized by the selective oxidation catalyst 151c. Then, the product gas exits from the inlet / outlet port 105 b and flows to the inlet 171 a of the anode 171 via the ports 110 c and 110 d of the direction switching valve 110. Then, an electrochemical reaction between hydrogen and oxygen occurs in the fuel cell 107, unreacted hydrogen burns in the catalytic combustor 108, and residual hydrogen burns and is removed in the hydrogen combustor 109. In this way, exhaust gas is discharged from the hydrogen combustor 109.

  As described above, while the fuel pump 102 and the air pump 106 are operating, the control unit 130 executes the routine shown in FIG. 14 every time a fixed time elapses. When the routine shown in FIG. 14 is started, the control unit 130 inputs the voltage output from the fuel cell 107 (step S101). The control unit 130 compares the detected voltage from the fuel cell 107 with a predetermined threshold value P (step S102). As a result of the comparison, when the detected voltage exceeds the predetermined threshold P and is recognized by the control unit 130 (step S102: Yes), the process returns to step S101. On the contrary, when the control unit 130 determines that the detected power is equal to or less than the predetermined threshold P (step S102: No), the control unit 130 switches the switching position of the direction switching valve 110 and sets the direction switching valve 110 to the first. The state is switched to the second state or vice versa (step S103), and the process returns to step S101.

  Here, in the carbon monoxide remover 105, when carbon monoxide is oxidized for a long time, the active sites of the selective oxidation catalyst 151c in the main reaction zone gradually adsorb carbon monoxide so that the carbon monoxide is gradually covered. As a result, the carbon monoxide oxidation performance of the selective oxidation catalyst 151c decreases. Then, the main reaction zone gradually moves from the vicinity of the inlet / outlet 105a of the reaction channel 151b to the inlet / outlet 105b side not covered with carbon monoxide.

  When the active sites of the selective oxidation catalyst 151c in the reaction channel 151b are covered with carbon monoxide, the carbon monoxide removal rate is reduced, and carbon monoxide flows into the electrodes of the fuel cell 107. Then, the Pt catalyst used for the anode 171 is poisoned, and the output of the fuel cell 107 decreases. If this state continues, the output voltage of the fuel cell 107 becomes equal to or lower than a predetermined threshold voltage P at a certain time. At this time, when the control unit 130 executes the process of FIG. 14, the detected voltage of the fuel cell 107 is equal to or less than the predetermined threshold P (step S102: No), so the control unit 130 changes the state of the direction switching valve 110 to the first state. The state is switched to the second state. Then, as shown in FIG. 15, the outlet 104b of the reformer 104 and the inlet / outlet port 105b of the carbon monoxide remover 105 are connected, and the inlet / outlet port 105a of the carbon monoxide remover 105 and the inlet 171a of the anode 171 are connected. Even if the control unit 130 executes the process of FIG. 14 before the output voltage of the fuel cell 107 becomes equal to or lower than the predetermined threshold (step S102: Yes), the control unit 130 changes the state of the direction switching valve 110. Maintain in the first state.

  After the direction switching valve 110 is switched, hydrogen gas or the like flows in the carbon monoxide remover 105 in the opposite direction to that in the past. That is, hydrogen gas or the like enters the reaction channel 151b from the entrance / exit 105b that has been on the exit side until then, and exits from the entrance / exit 105b through the reaction channel 151b to the entrance / exit 105a. Since the active site of the selective oxidation catalyst 151c near the entrance / exit 105b has hardly contributed to the reaction so far, it is hardly covered with carbon monoxide at this point. Therefore, the vicinity of the entrance / exit 105b becomes a new main reaction zone, and the carbon monoxide oxidizing ability is restored to almost the initial level. As a result, the output power detected by the DC / DC converter 120 also rises to the initial level.

  In addition, by removing carbon monoxide in the new main reaction zone, hydrogen from which carbon monoxide has been substantially removed on the carbon monoxide covering the active sites of the selective oxidation catalyst 151c in the vicinity of the inlet / outlet 105b. Gas etc. pass through. Since the partial pressure of carbon monoxide contained in the fluid containing hydrogen gas or the like is reduced, the carbon monoxide adsorbed on the active sites of the selective oxidation catalyst 151c is released into the hydrogen gas or the like that flows. If the removal of carbon monoxide is continued, the carbon monoxide that has covered the active sites of the selective oxidation catalyst 151c at a certain time is removed. Although carbon monoxide is released, carbon monoxide contained in hydrogen gas or the like sent to the fuel cell 107 slightly increases. However, since the increase is small, there is almost no influence on the fuel cell 107.

  When the state in which the flow in the carbon monoxide remover 105 is directed from the inlet / outlet 105b toward the inlet / outlet 105a continues for a while, the active points of the selective oxidation catalyst 151c near the inlet / outlet 105b start to be covered with carbon monoxide. Then, carbon monoxide that cannot be removed flows into the fuel cell 107, and the output voltage of the fuel cell 107 decreases. As a result, the output voltage of the fuel cell 107 becomes a predetermined threshold value P or less. At this time, when the control unit 130 executes the process shown in FIG. 14, the detection voltage by the fuel cell 107 converter 120 is equal to or lower than the predetermined threshold P (step S102: No), so the control unit 130 changes the state of the direction switching valve 110. Switch from the second state to the first state. Therefore, the flow becomes the state shown in FIG.

  In this way, the reaction is carried out by the selective oxidation catalyst 151c in the vicinity of one of the entrances 105a and 105b that is not covered with carbon monoxide, and the selective oxidation catalyst 151c having a reduced performance is simultaneously restored in the other vicinity. Is done. When the removal of carbon monoxide proceeds and the active sites of the selective oxidation catalyst 151c start to be coated with carbon monoxide, the flow of carbon monoxide or the like is switched in the reverse direction. By repeating this operation. Removal of carbon monoxide can be continuously performed while maintaining high performance at all times.

  In the first embodiment, the mechanism for continuously performing the reforming reaction and the mechanism for continuously removing carbon monoxide in the second embodiment have been described separately, but these two embodiments are combined. You may be able to do it simultaneously.

It is a block diagram which shows the structure of the electric power generation and reaction system which concerns on 1st Embodiment of this invention. It is a top view which shows the reformer used in the embodiment. It is a bottom view which shows the reformer used in the embodiment. It is sectional drawing which shows the reformer used in the embodiment. It is the schematic which shows the direction switching valve and reformer which are used in the embodiment. It is the schematic which shows the direction switching valve and reformer which are used in the embodiment. It is the block diagram which showed the circuit structure of the electric power generation and reaction system in the embodiment. It is the flowchart which showed the flow of the process by the control part of the electric power generation and reaction system in the embodiment. It is a graph which shows channel temperature distribution of the above-mentioned reformer. It is a block diagram which shows the structure of the electric power generation and reaction system which concerns on the same embodiment. It is a block diagram which shows the structure of the fuel cell electric power generating apparatus which concerns on 2nd Embodiment of this invention. It is sectional drawing which shows the carbon monoxide remover used in the embodiment. It is the block diagram which showed the circuit structure of the electric power generation and reaction system in the embodiment. It is the flowchart which showed the flow of the process by the control part of the power generation and reaction in the same embodiment. It is a block diagram which shows the structure of the electric power generation and reaction system in the embodiment.

Explanation of symbols

100, 200 Fuel cell power generation device 100a, 200a Reaction system 1 Fuel container 2, 102 Fuel pump 3 Vaporizer (upstream processor)
4 Reformer (catalytic reactor)
104 Reformer (upstream processing machine)
41 Substrate 41b, 151b Reaction channel 41c Reforming catalyst 42 Glass substrate 44a First temperature sensor 44b Second temperature sensor 5 Carbon monoxide remover (downstream reactor)
105 Carbon monoxide remover (catalytic reactor)
151c Selective oxidation catalyst 6, 106 Air pump 7 Fuel cell 107 Fuel cell (downstream reactor)
71, 171 Anode 72 Cathode 73 Electrolyte membrane 8 Catalytic combustor 9 Hydrogen combustor 10, 110 Direction switching valve (switching unit)
20, 120 DC / DC converter (power detector)
30, 130 Control unit tx1 Temperature tx2 detected by the first temperature sensor Temperature detected by the second temperature sensor

Claims (3)

A catalytic reactor that is a reformer having two inlets , a reaction channel provided from one to the other of the two inlets, and a catalyst provided in the reaction channel;
An upstream processor that is a vaporizer that performs fuel processing and delivers the processed product from an outlet to the catalytic reactor;
A downstream reactor that is a carbon monoxide remover that takes in the product that has passed through the catalytic reactor from an inlet and reacts the taken product;
A first state in which one of the two outlets is connected to an outlet of the upstream processor and the other is connected to an inlet of the downstream reactor, and the other is connected to an outlet of the upstream processor. A switching unit that selectively switches to a second state in which one is connected to the inlet of the downstream reactor;
A first temperature detection unit that is provided on one side of the two entrances and detects the temperature of the one side;
A second temperature detector provided on the other side of the two entrances and detecting the temperature on the other side;
And a control unit that controls the direction switching unit based on temperatures detected by the first temperature detection unit and the second temperature detection unit . The control unit obtains a difference between a temperature detected by the first temperature detecting unit and a temperature detected by the second temperature detecting unit, and when the obtained difference is equal to or less than a predetermined threshold, the switching unit is changed to the first temperature detecting unit. The reaction system according to claim 1 , wherein the reaction system is switched from a state to the second state or vice versa. The control unit obtains a difference between a temperature detected by the first temperature detecting unit and a temperature detected by the second temperature detecting unit, and when the obtained difference exceeds a predetermined threshold value, the control unit sets the first switching unit to the first temperature detecting unit. the reaction system of claim 1 or 2, characterized in that to maintain the state or the second state.

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