WO2019229997A1 - Catalytic reaction system and fuel cell system - Google Patents

Abstract

This catalytic reaction system produces a fuel gas by vaporizing a liquid fuel, and causes a catalytic reaction of the fuel gas. This catalytic reaction system comprises: an injection part which injects a liquid fuel; a first heater which produces a fuel gas by heating and vaporizing the liquid fuel injected from the injection part; a catalyst which causes a catalytic reaction of the fuel gas that is produced by the first heater; a second heater which heats the catalyst; and a controller which controls a first temperature that is the temperature of the first heater and a second temperature that is the temperature of the second heater. The controller controls the temperatures such that the first temperature is lower than the second temperature.

Description

Catalytic reaction system and fuel cell system

The present invention relates to a catalytic reaction system and a fuel cell system.

According to JP2013-253004A, a heater is provided in front of the catalyst. When the liquid fuel is injected toward the catalyst, the injected liquid fuel is vaporized to generate fuel gas, and the fuel gas is generated by the catalyst. The technology to be reacted is disclosed. According to this technique, the progress of the catalytic reaction can be promoted by preheating the catalyst using a heater at the time of startup or the like.

Depending on the type of liquid fuel, the temperature at which the vaporization of the liquid fuel suitably proceeds may differ from the temperature at which the catalytic reaction of the fuel gas suitably proceeds. Therefore, in the catalytic reaction system disclosed in JP2013-253004A, even if the catalytic reaction is promoted, the progress of vaporization of the fuel gas is hindered, and the reaction may not be promoted as a whole of the catalytic reaction system.

According to one aspect of the present invention, the catalytic reaction system vaporizes liquid fuel to generate fuel gas, and causes the fuel gas to undergo a catalytic reaction. The catalytic reaction system is generated by an injection unit that injects liquid fuel, a first heater that generates fuel gas by heating and vaporizing the liquid fuel injected from the injection unit, and the first heater. A catalyst for catalytic reaction of fuel gas, a second heater for heating the catalyst, a first temperature that is a temperature of the first heater, and a controller that controls a second temperature that is the temperature of the second heater; Have The controller controls the first temperature to be lower than the second temperature.

FIG. 1 is a schematic configuration diagram of a catalytic reaction system according to a first embodiment. FIG. 2 is a graph showing the vaporization time of the liquid fuel. FIG. 3 is a flowchart showing temperature control. FIG. 4 is a flowchart showing temperature control. FIG. 5A is a cross-sectional view of a catalytic reactor of a comparative example. FIG. 5B is a cross-sectional view of the catalytic reactor of the present embodiment. FIG. 6 is a schematic configuration diagram of the catalytic reactor according to the second embodiment. FIG. 7 is a schematic configuration diagram of the catalytic reactor according to the third embodiment. FIG. 8 is a schematic configuration diagram of the catalytic reactor of the fourth embodiment. FIG. 9 is a schematic configuration diagram of a catalytic reactor according to a fifth embodiment. FIG. 10 is a schematic configuration diagram of a fuel cell system according to the sixth embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic configuration diagram of a catalytic reaction system 100 according to the first embodiment.

The catalytic reaction system 100 includes a catalytic reactor 10, an injector 20 that is an injector that injects and supplies liquid fuel to the catalytic reactor 10, a fuel tank 30 that stores the liquid fuel, and a controller 40. In the catalytic reaction system 100, an oxidation catalytic reaction is performed. Therefore, in the catalytic reaction system 100, the fuel gas generated from the liquid fuel undergoes an oxidation catalytic reaction, and finally the oxidized fuel gas (hereinafter referred to as oxidizing gas) is supplied to another system. At the same time, since the oxidation catalyst reaction is an exothermic reaction, the device arranged in the vicinity of the catalyst reaction system 100 can be heated by heat exchange.

The catalytic reactor 10 functions as a fuel injection chamber that receives liquid fuel injected from the injector 20. The catalytic reactor 10 includes a first heater 11, a second heater 12, and a catalyst 13. The catalytic reactor 10 includes, for example, a cylindrical casing 14 having a substantially circular cross section, and the liquid fuel is heated and vaporized inside the casing 14 along the cylinder from upstream to downstream. A first heater 11 that is heated, a second heater 12 that can be heated at a higher temperature than the first heater 11, and a catalyst 13 that catalyzes the fuel gas adjacent to the second heater 12. . In addition, since the 1st heater 11 and the 2nd heater 12 are spaced apart, heat does not conduct mutually and temperature control can be performed individually.

An injector 20 for injecting and supplying liquid fuel toward the first heater 11 is disposed on the upstream end face of the catalyst reactor 10. In the space upstream of the catalyst reactor 10, that is, in the upstream side of the casing 14, liquid fuel is supplied from the injector 20 via the fuel supply path 51 from the fuel tank 30, and air is supplied via the air supply path 52. Is captured. The air supply path 52 is provided with a valve 52A, and the flow rate of air supplied to the catalytic reactor 10 is controlled by operating the valve 52A. In the space downstream of the catalyst reactor 10, that is, in the downstream side of the housing 14, the oxidizing gas is supplied to other devices via the oxidizing gas passage 53.

The first heater 11 includes a honeycomb structure 11A as a main body and a first electrode part 11B provided on the outer periphery of the honeycomb structure 11A. The honeycomb structure 11 </ b> A is configured as a metal cylindrical member, and is fixed in the housing 14. The first electrode portion 11B is provided so as to be exposed to the outside from the inside of the catalyst reactor 10, and the honeycomb structure 11A is heated by energizing the first electrode portion 11B. The first heater 11 includes a first temperature sensor 11C capable of measuring its own temperature. In addition, the 2nd heater 12 is comprised by 12A of honeycomb structures, the 2nd electrode part 12B, and the 2nd temperature sensor 12C similarly to the 1st heater 11. FIG.

The catalyst 13 is accommodated in the housing 14 and arranged side by side so that the upstream end surface of the catalyst 13 and the downstream end surface of the second heater 12 are in contact with each other. The catalyst 13 is a member in which a catalyst material is supported on the surface of a honeycomb structure as a carrier. The honeycomb structure is configured as a metal cylindrical member, and platinum (Pt), palladium (Pd), or the like is used as a catalyst material supported on the honeycomb structure.

In the present embodiment, the second heater 12 and the catalyst 13 are configured as separate bodies, but the second heater 12 and the catalyst 13 may be integrally formed. For example, the catalytic function can be added to the second heater 12 by utilizing the honeycomb structure 12A of the second heater 12 as a carrier and supporting the catalyst material on the surface of the honeycomb structure 12A. By integrally forming in this way, the configuration of the catalytic reactor 10 can be simplified.

The injector 20 is connected to the fuel tank 30 via a fuel supply path 51, and the fuel tank 30 is provided with a supply pump 31 for supplying liquid fuel to the injector 20. The injector 20 is provided at the center of the end of the catalyst reactor 10, but is provided at a position where liquid fuel can be injected toward the first heater 11 provided in the catalyst reactor 10. Just do it.

The fuel tank 30 stores liquid fuel. The liquid fuel is, for example, a fuel composed of water and ethanol (for example, water-containing ethanol containing 45% by volume of ethanol). The liquid fuel is not limited to hydrous ethanol, and may be a liquid fuel containing gasoline or methanol.

Liquid fuel stored in the fuel tank 30 is injected and supplied from the injector 20 to the catalytic reactor 10. The supplied liquid fuel is heated and vaporized by the first heater 11 to generate fuel gas. The fuel gas is catalyzed by the catalyst 13 heated by the second heater 12. The catalytic reaction in this embodiment is an oxidation catalytic reaction, and an oxidizing gas is generated by the oxidation catalytic reaction. The oxidizing gas is supplied to other devices through the oxidizing gas passage 53.

The operation of various devices used for the operation of the first heater 11, the second heater 12, the injector 20, and other catalytic reaction systems 100 is controlled by the controller 40. The controller 40 is configured as an electronic control unit including a central processing circuit, various storage devices such as a ROM and a RAM, and an input / output interface.

The controller 40 receives information on the measured temperature from the first temperature sensor 11C of the first heater 11 and the second temperature sensor 12C of the second heater 12. The controller 40 may be configured to receive signals from various sensors that detect the temperature and concentration of the liquid fuel supplied to the injector 20 and other operating states of the catalytic reaction system 100.

The controller 40 controls the first calorific value Q1 of the first heater 11 by changing the first current I1 applied to the first electrode part 11B. The controller 40 controls the second calorific value Q2 of the second heater 12 by changing the second current I2 applied to the second electrode portion 12B. Further, the controller 40 controls the injection amount V of the liquid fuel from the injector 20.

Here, the properties of the liquid fuel used in this embodiment will be described with reference to FIG. FIG. 2 is a graph showing the vaporization time of the liquid fuel in the first heater 11. The vertical axis represents the liquid fuel vaporization time t, and the horizontal axis represents the first heating temperature T1, which is the temperature of the first heater 11.

When the first heating temperature T1 is relatively low, the vaporization time t decreases as the first heating temperature T1 increases, and when the first heating temperature T1 is the vaporization optimum temperature Ta, the vaporization time t becomes the shortest. . When the first heating temperature T1 is higher than the vaporization optimum temperature Ta, the vaporization time t becomes longer as the first heating temperature T1 increases.

This is because when the liquid fuel is vaporized, the fuel gas that has already vaporized exists around the liquid fuel that has not been vaporized, so that the fuel gas functions as a heat insulating material, and heat to the unvaporized liquid fuel. This may be due to suppression of conduction. In the temperature range where the first heating temperature T1 is higher than the vaporization optimum temperature Ta, vaporization proceeds rapidly, and a lot of fuel gas exists around the unvaporized liquid fuel. Therefore, heat conduction to the unvaporized liquid fuel. Is suppressed. Therefore, the vaporization time t becomes longer as the first heating temperature T1 increases. This phenomenon is called the Leidenfrost phenomenon.

In the catalyst 13, the catalytic reaction suitably proceeds when the catalyst temperature is higher than the optimum catalyst temperature Tb. The optimum catalyst temperature Tb is higher than the optimum vaporization temperature Ta, and when the liquid fuel is hydrous ethanol having a relatively high concentration, the difference between the optimum catalyst temperature Tb and the optimum vaporization temperature Ta is relatively significant. . For example, when there is only one heater, it is conceivable to control the heater at a catalyst optimum temperature Tb having a high temperature. In this case, if both the vaporization of the liquid fuel and the heating of the catalyst 13 are performed at the high catalyst optimum temperature Tb, the Leidenfrost phenomenon occurs in the vaporization of the liquid fuel, and the progress of the vaporization is suppressed. There is a risk.

The controller 40 controls the first heating temperature T1 to be close to the vaporization optimum temperature Ta, and controls the second heating temperature T2 to be higher than the catalyst optimum temperature Tb. By doing in this way, the liquid fuel ejected from the injector 20 is suppressed from the Leidenfrost phenomenon and is suitably vaporized by the first heater 11. In addition, the fuel gas vaporized in this manner suitably undergoes a catalytic reaction in the catalyst 13 heated to a temperature higher than the optimum catalyst temperature Tb.

It should be noted that the illustrated first temperature zone Tx and second temperature zone Ty are used for specific temperature control in the controller 40.

The first temperature zone Tx is a temperature zone in which the vaporization time t is shorter than the first predetermined time tx and the vaporization time t can be substantially ignored. By controlling the first heating temperature T1 so as to be included in the first temperature zone Tx, the vaporization of the liquid fuel can be suitably advanced.

The second temperature zone Ty is a temperature zone in which the vaporization time t is shorter than the second predetermined time ty. In the catalytic reaction system 100, there is a reaction rate of the system determined by the output of the oxidizing gas with respect to the input of the liquid fuel. That is, this reaction rate is a rate at which the reaction between the vaporization of the liquid fuel and the catalytic reaction of the fuel gas is performed without delay. The second predetermined time ty is a vaporization time t necessary for the reaction rate of the entire system to satisfy the required level. That is, when the vaporization time t is equal to or shorter than the second predetermined time ty, the overall reaction rate of the catalytic reaction system 100 satisfies the required level. On the other hand, when the vaporization time t is longer than the second predetermined time ty, the reaction rate of the entire system does not satisfy the required level. Since the second predetermined time ty is higher than the first predetermined time tx, the second temperature zone Ty is a temperature zone including the first temperature zone Tx.

3 and 4 are flowcharts showing temperature control by the controller 40. FIG. This temperature control is stored as a program in the controller 40, and the temperature control is performed by executing the program stored in the controller 40.

As shown in FIG. 3, in step S <b> 1, the controller 40 acquires a first heating temperature T <b> 1 that is the temperature of the first heater 11 from the first temperature sensor 11 </ b> C.

In step S2, control based on the second temperature zone Ty shown in FIG. 2 is performed. Step S2 includes the control of steps S21 to S24. In the second temperature zone Ty, the upper limit temperature is the second upper limit temperature Ty_h, and the lower limit temperature is the second lower limit temperature Ty_l.

In step S21, the controller 40 determines whether or not the first heating temperature T1 exceeds the second upper limit temperature Ty_h (T1> Ty_h). When the first heating temperature T1 is higher than the second upper limit temperature Ty_h (S21: Yes), the controller 40 next allows the first heating temperature T1 in order for the overall reaction rate of the catalytic reaction system 100 to satisfy the required rate. The process of step S22 is performed so that T1 is lowered and included in the second temperature zone Ty. When the first heating temperature T1 is equal to or lower than the second upper limit temperature Ty_h (S21: No), the controller 40 next performs the process of step S23.

In step S22, the controller 40 increases the injection amount V of the liquid fuel from the injector 20. By doing so, the amount of heat necessary for vaporizing the liquid fuel in the first heater 11 increases, and the first heating temperature T1 decreases. The controller 40 proceeds to the process of step S5 after the process of step S22.

In step S23, the controller 40 determines whether or not the first heating temperature T1 is lower than the second lower limit temperature Ty_l (T1 <Ty_l). When the first heating temperature T1 is lower than the second lower limit temperature Ty_l (S23: Yes), the controller 40 then selects the first heating temperature so that the overall reaction rate of the catalytic reaction system 100 satisfies the required rate. The process of step S24 is performed so that T1 is raised and included in the second temperature zone Ty. When the first heating temperature T1 is equal to or lower than the second lower limit temperature Ty_l (S23: No), the controller 40 next performs a process of step S3.

In step S24, the controller 40 decreases the injection amount V of the liquid fuel from the injector 20. By doing so, the amount of heat necessary for vaporizing the liquid fuel in the first heater 11 is reduced, and the first heating temperature T1 is increased. The controller 40 proceeds to the process of step S5 after the process of step S24.

In step S3, control based on the first temperature zone Tx shown in FIG. 2 is performed. Step S3 includes the control of steps S31 to S34. In the first temperature zone Tx, the upper limit temperature is the first upper limit temperature Tx_h, and the lower limit temperature is the first lower limit temperature Tx_l.

In step S31, the controller 40 determines whether or not the first heating temperature T1 exceeds the first upper limit temperature Tx_h (T1> Tx_h). When the first heating temperature T1 exceeds the first upper limit temperature Tx_h (S31: Yes), the controller 40 then decreases the first heating temperature T1 in order to shorten the liquid fuel vaporization time t. The process of step S32 is performed so as to be included in the first temperature zone Tx. When the first heating temperature T1 is equal to or lower than the first upper limit temperature Tx_h (S31: No), the controller 40 next performs a process of step S33.

In step S32, the controller 40 reduces the first heating value T1 in the first heater 11 by decreasing the first current I1 applied to the first electrode portion 11B, thereby decreasing the first heating temperature T1. Let The controller 40 proceeds to the process of step S5 after the process of step S32.

In step S33, the controller 40 determines whether or not the first heating temperature T1 is lower than the first lower limit temperature Tx_l (T1 <Tx_l). When the first heating temperature T1 is lower than the first lower limit temperature Tx_l (S33: Yes), the controller 40 next increases the first heating temperature T1 in order to shorten the liquid fuel vaporization time t. The process of step S34 is performed so as to be included in the first temperature zone Tx. When the first heating temperature T1 is equal to or lower than the first lower limit temperature Tx_l (S52: No), the controller 40 next performs the process of step S4.

In step S34, the controller 40 increases the first heating value T1 by increasing the first heating value T1 by increasing the first current I1. Then, the controller 40 proceeds to the process of step S5 after the process of step S34.

In step S4, the controller 40 sets the injection amount V of the liquid fuel from the injector 20 and the first current I1 to predetermined values. The first calorific value Q1 becomes a predetermined value according to the first current I1. The predetermined value is such that the first heating temperature T1 of the first heater 11 becomes the optimum vaporization temperature Ta shown in FIG. It is determined in advance so that the reaction proceeds constantly without delay. And the controller 40 progresses to the process of step S5 after the process of step S4.

In step S5, the second heating value Q2 in the second heater 12 is controlled.

FIG. 4 is a flowchart showing details of the control of the second calorific value Q2 in step S5.

In step S51, the controller 40 acquires the second heating temperature T2 of the second heater 12 from the second temperature sensor 12C.

In step S52, the controller 40 determines whether or not the second heating temperature T2 is lower than the optimum catalyst temperature Tb of the fuel gas (T2 <Tb). When the second heating temperature T2 is lower than the optimum catalyst temperature Tb (S52: Yes), the controller 40 next increases the second heating temperature T2 in order to appropriately proceed the catalytic reaction of the fuel gas. Step S53 is performed so as to exceed the catalyst optimum temperature Tb. When the second heating temperature T2 is equal to or higher than the catalyst optimum temperature Tb (S52: No), the controller 40 next performs the process of step S54.

In Step S53, the controller 40 increases the second heat generation amount Q2 in the second heater 12 by increasing the second current I2 applied to the second electrode portion 12B. By doing in this way, the 2nd heating temperature T2 rises. And the controller 40 complete | finishes control of the 2nd calorific value Q2 after the process of step S53.

In step S54, the controller 40 sets the second current I2 to a predetermined value. This predetermined value is determined in advance so that the catalyst 13 exceeds the second heating temperature T2 and the catalytic reaction proceeds in a steady manner without delay. And the controller 40 complete | finishes control of the 2nd calorific value Q2 after the process of step S54.

Such control allows the catalytic reaction in the catalytic reaction system 100 to proceed appropriately.

According to the first embodiment, the following effects can be obtained.

According to the catalytic reaction system 100 of the first embodiment, the first heater 11 and the second heater 12 are provided. The first heater 11 is used for vaporizing the liquid fuel, and the second heater 12 is used for heating the catalyst 13. Here, as shown in FIG. 2, the catalytic reaction suitably proceeds when the temperature is higher than the optimum catalyst temperature Tb, and the vaporization of the liquid fuel suitably proceeds at the optimum vaporization temperature Ta lower than the optimum catalyst temperature Tb.

For example, FIG. 5A is a cross-sectional view of a catalytic reactor 10 of a comparative example. FIG. 5B is a cross-sectional view of the catalytic reactor 10 of the present embodiment. In these drawings, liquid fuel is injected from the injector 20.

In the comparative example shown in FIG. 5A, the first heating temperature T1 of the first heater 11 is controlled to be the optimum catalyst temperature Tb in the same manner as the second heating temperature T2 of the second heater 12. . When the liquid fuel is heated by the first heater 11, the vaporization rate of the liquid fuel becomes slow due to the Leidenfrost phenomenon. Therefore, a portion of the injected liquid fuel does not vaporize and remains on the inner wall at the bottom of the housing 14 as the residual liquid fuel 15. The residual liquid fuel 15 flows downstream from the first heater 11 and reaches the catalyst 13. In the catalyst 13, the residual liquid fuel 15 is not subjected to a catalytic reaction, and the residual liquid fuel 15 is vaporized. However, since the catalyst 13 is controlled to be at the second heating temperature T2, the Leidenfrost phenomenon occurs, and the vaporization of the residual liquid fuel 15 is suppressed. As described above, the generation of the fuel gas is hindered, and the progress of the reaction of the entire catalytic reaction system 100 may be suppressed.

In contrast, in the present embodiment shown in FIG. 5B, the first heating temperature T1 is lower than the second heating temperature T2. Therefore, when the liquid fuel is vaporized by the first heater 11, the Leidenfrost phenomenon is suppressed, so that the liquid fuel is rapidly vaporized and the residual liquid fuel 15 does not reach the catalyst 13. . Thus, since the vaporization of the liquid fuel in the first heater 11 can be promoted and the progress of the catalytic reaction in the catalyst 13 can be promoted, the reaction of the entire catalytic reaction system 100 can be promoted.

According to the catalytic reaction system 100 of the first embodiment, the controller 40 controls the first heating temperature T1 to be included in the first temperature zone Tx in step S3. Specifically, when it is determined that the first heating temperature T1 is higher than the first upper limit temperature Tx_h (S31: Yes), the controller 40 decreases the first heating value Q1 in the first heater 11. (S32). When it is determined that the first heating temperature T1 is lower than the first lower limit temperature Tx_l (S33: Yes), the controller 40 increases the first heating value Q1 (S33). In this way, the first heating temperature T1 is controlled so as to be included in the first temperature zone Tx.

As shown in FIG. 2, in the first temperature zone Tx, the vaporization time t is shorter than the first predetermined time tx, and the first predetermined time tx is very short. Therefore, by controlling the first heating temperature T1 to be included in the first temperature zone Tx, the vaporization of the liquid fuel is promoted, and the reaction of the entire catalytic reaction system 100 can be promoted.

According to the catalytic reaction system 100 of the first embodiment, the controller 40 controls the first heating temperature T1 to be included in the second temperature zone Ty in step S2. The second temperature zone Ty is a temperature zone in which the vaporization time t is shorter than the second predetermined time ty.

In the catalytic reaction system 100, there is a reaction speed of the entire system determined by the output of the oxidizing gas with respect to the input of the liquid fuel. This reaction rate is determined by the rate of both the vaporization of the liquid fuel and the catalytic reaction of the fuel gas. The second predetermined time ty is a vaporization time t necessary for the reaction rate of the system to satisfy the required level. Therefore, when the first heating temperature T1 is included in the second temperature zone Ty, the reaction rate of the entire catalytic reaction system 100 can satisfy the required level.

According to the catalytic reaction system 100 of the first embodiment, in Step S21, the controller 40 determines that the first heating temperature T1 is higher than the second upper limit temperature Ty_h (S21: Yes), the injector 20 The injection amount V of the liquid fuel from is increased (S22). As the injection amount V increases, a large amount of heat is required to vaporize the liquid fuel, so the first heating temperature T1 decreases. The temperature change due to the change in the injection amount V of the liquid fuel is more immediate than the temperature change caused by the first current I1 in the first heater 11. Therefore, since the temperature change of 1st heating temperature T1 can be performed rapidly, the fall of the reaction rate of the catalyst reaction system 100 whole is suppressed.

According to the catalytic reaction system 100 of the first embodiment, in Step S22, the controller 40 determines that the first heating temperature T1 is lower than the second lower limit temperature Ty_l (S23: Yes), the injection amount. V is decreased (S24). As the injection amount V decreases, the amount of heat necessary for vaporizing the liquid fuel decreases, so the first heating temperature T1 increases. As described above, the first heating temperature T1 can be raised by a method having higher immediacy than the control of the first current I1, and therefore, the reaction rate of the catalytic reaction system 100 as a whole can be changed quickly by changing the first heating temperature T1. Can be suppressed.

In the processing of steps S22 and S24, the amount of air supplied from the air supply path 52 may be increased or decreased by controlling the valve 52A instead of increasing or decreasing the injection amount V. Specifically, if it is determined that the one heating temperature T1 is higher than the second upper limit temperature Ty_h (S21: Yes), the controller 71 can easily increase the air amount to lower the temperature. To do. On the other hand, when it is determined that the first heating temperature T1 is lower than the second lower limit temperature Ty_l (S23: Yes), the controller 40 reduces the air amount to make it easy to raise the temperature. The increase / decrease in the injection amount V and the increase / decrease in the air amount may be performed simultaneously.

According to the catalytic reaction system 100 of the first embodiment, the controller 40 determines that the second heating temperature T2 is lower than the optimum catalyst temperature Tb (T2 <Tb) (S52: Yes). By increasing the second calorific value Q2 of the heater 12 (S53), the second heating temperature T2 is raised. Thus, since the catalyst 13 has a temperature suitable for the catalytic reaction, the catalytic reaction of the fuel gas is promoted, and the reaction of the entire catalytic reaction system 100 can be promoted.

According to the catalytic reaction system 100 of the first embodiment, the first heater 11 and the second heater 12 are separated from each other in the housing 14. By being configured in this manner, heat conduction between the first heater 11 and the second heater 12 is suppressed, so that the controller 40 controls the first heating temperature T1 and the second heating temperature T2 individually. Can be done appropriately. Therefore, both the vaporization of the liquid fuel and the catalytic reaction of the fuel gas are promptly performed, and the reaction of the entire catalytic reaction system 100 can be promoted.

(Second Embodiment)
In the first embodiment, the case where the casing 14 of the catalytic reactor 10 is cylindrical and the central axis thereof is a straight line has been described. In 2nd thru | or 4th embodiment, the case where the central axis of the housing | casing 14 is shapes other than a straight line is demonstrated. In the second to fourth embodiments, the injector 20 may be inclined with respect to the central axis of the housing 14 so that the injected liquid fuel hits the first heater 11.

FIG. 6 is a schematic configuration diagram of the catalytic reactor 10 of the second embodiment.

The housing 14 has a cylindrical shape with a substantially circular cross section, and its central axis is bent. Specifically, the casing 14 is provided with a first casing 14A, a second casing 14B, and a third casing 14C adjacent to each other in the direction from upstream to downstream, and the central axes of the casings 14A are the same. It is configured not to be on the line.

The first housing 14A and the third housing 14C are provided such that their central axes are horizontal and in the same direction. The third housing 14C is provided above the first housing 14A in the vertical direction. Therefore, the second casing 14B that connects the first casing 14A and the third casing 14C is provided so as to be inclined upward from the upstream toward the downstream.

The first heater 11 is provided in the second casing 14B, and the second heater 12 and the catalyst 13 are provided in the third casing 14C. With this configuration, the residual liquid fuel 15 that has not been vaporized in the first heater 11 remains on the inner wall surface (inner bottom portion) located at the bottom of the first housing 14A. The catalyst 13 provided at 14C is not reached.

Furthermore, the catalytic reactor 10 is provided with a third heater 16 configured to be able to heat the bottom of the first housing 14A where the residual liquid fuel 15 remains from the outside. Since the third heater 16 is controlled by the controller 40 in the same temperature zone as the first heater 11, vaporization of the residual liquid fuel 15 is promoted.

According to the second embodiment, the following effects can be obtained.

According to the catalytic reaction system 100 of the second embodiment, the first heater 11 is provided below the second heater 12 and the catalyst 13 in the vertical direction. The residual liquid fuel 15 that has not been vaporized in the first heater 11 remains at the bottom of the first housing 14 </ b> A before the first heater 11 in the flow path direction. With such a configuration, the residual liquid fuel 15 does not reach the catalyst 13 above the bottom of the first housing 14A, so that the Leidenfrost phenomenon in the catalyst 13 controlled by the second heating temperature T2 occurs. By being suppressed, vaporization of the liquid fuel is promoted, and the reaction in the entire catalytic reaction system 100 can be promoted.

According to the catalytic reaction system 100 of the second embodiment, the third heater 16 that heats the bottom of the first housing 14A where the residual liquid fuel 15 stays is provided. Since the third heater 16 is controlled at the same temperature as the first heater 11, vaporization of the residual liquid fuel 15 is promoted. With this configuration, all of the liquid fuel injected from the injector 20 is vaporized, so that the reaction rate in the entire catalytic reaction system 100 can satisfy the required level.

(Third embodiment)
FIG. 7 is a schematic configuration diagram of the catalytic reactor 10 of the third embodiment.

As shown in this figure, the center axis of the second housing 14B is provided in the vertical direction, and the end surface on the downstream side of the first housing 14A and the end surface on the upstream side of the third housing 14C are third. It is connected to the side surface of the housing 14C. The first heater 11 is provided on a side surface of the second casing 14B that is connected to the third casing 14C, and the second heater 12 and the catalyst 13 are provided on the third casing 14C.

Even in such a configuration, the residual liquid fuel 15 remains on the inner end face (inner bottom) located at the bottom of the second casing 14B. Therefore, since the residual liquid fuel 15 does not reach the catalyst 13, the Leidenfrost phenomenon in the catalyst 13 is suppressed. Further, the residual liquid fuel 15 remaining at the bottom of the second casing 14B is heated by the third heater 16 to promote vaporization. In this way, the vaporization of the liquid fuel proceeds promptly, and the reaction in the entire catalytic reaction system 100 can be promoted.

(Fourth embodiment)
FIG. 8 is a schematic configuration diagram of the catalytic reactor 10 of the fourth embodiment. As shown in this figure, the first casing 14A is inclined downward along the flow path, and the third casing 14C is inclined upward along the flow path. A second housing 14B is provided between the first housing 14A and the third housing 14C. In this way, the housing 14 is configured in a crank shape. The first heater 11, the second heater 12, and the catalyst 13 are provided in the third housing 14C.

In such a configuration, since the second casing 14B is at the lowest position, the residual liquid fuel 15 remains on the inner bottom portion of the second casing 14B. And the 3rd heater 16 is provided so that the bottom part of the 2nd housing | casing 14B may be heated. Even in such a configuration, the residual liquid fuel 15 does not reach the catalyst 13 and the residual liquid fuel 15 is heated by the third heater 16 to promote vaporization, so that the vaporization of the liquid fuel proceeds promptly. The reaction in the entire catalytic reaction system 100 can be promoted.

(Fifth embodiment)
FIG. 9 is a schematic configuration diagram of the catalytic reactor 10 of the fifth embodiment. In the fifth embodiment, similarly to the first embodiment, the casing 14 is cylindrical, and the center axis thereof is configured to be a straight line. In this example, it is assumed that the temperature of the first heater 11 cannot be controlled for some reason.

In such a case, the residual liquid fuel 15 that is a part of the liquid fuel that has not been vaporized may remain in the vicinity of the catalyst 13 on the inner wall surface at the bottom of the casing 14. And the 3rd heater 16 is provided so that the bottom part of the housing | casing 14 in which this residual liquid fuel 15 may remain may be heated. Even if configured in this manner, the residual liquid fuel 15 that has not been vaporized is heated by the third heater 16 and vaporization is promoted, so that the vaporization of the liquid fuel proceeds promptly as a whole, and the catalytic reaction system 100 The overall reaction can be promoted.

(Sixth embodiment)
In the sixth embodiment, a fuel cell system 200 including the catalytic reaction system 100 of the first embodiment will be described. FIG. 10 is a schematic configuration diagram of the fuel cell system 200.

In addition to the catalytic reaction system 100, the fuel cell system 200 includes a fuel cell stack (F / C) 210, an evaporator (VAP) 220, a fuel heat exchanger (HEX) 230, and a reformer (REF) 240. And an air heat exchanger (AHEX) 250.

The fuel cell stack 210 is configured by stacking a plurality of fuel cells or fuel cell unit cells, and each fuel cell as a power generation source is, for example, a solid oxide fuel cell (SOFC). The fuel cell stack 210 includes an anode gas passage 201 that supplies fuel gas (anode gas) to the anode electrode of the fuel cell, an anode offgas passage 202 that flows the anode offgas after the power generation reaction discharged from the anode electrode, and a fuel cell A cathode gas passage 203 that supplies an oxidant gas (cathode gas) to the cathode electrode and a cathode offgas passage 204 through which the cathode offgas after the power generation reaction discharged from the cathode electrode flows.

The fuel cell stack 210 is a battery that generates power upon receiving supply of anode gas and cathode gas. The power generated by the fuel cell stack 210 is used to charge a battery mounted on the vehicle or drive an electric motor or the like.

The fuel tank 30 and the fuel cell stack 210 are connected through the anode gas passage 201. In the anode gas passage 201, an evaporator 220, a fuel heat exchanger 230, and a reformer 240 are provided in order from the upstream side in the flow direction. The liquid fuel is, for example, hydrous ethanol that is a mixed liquid of water and ethanol.

The evaporator 220 heats the liquid fuel by heat exchange with the combustion gas (oxidizing gas) supplied from the catalytic reactor 10 through the oxidizing gas passage 53. Since the liquid fuel stored in the fuel tank 30 is vaporized by heating, fuel gas is generated. In the anode gas passage 201, an injector 201A is provided at the inlet of the evaporator 220, and the supply of liquid fuel is controlled.

The fuel heat exchanger 230 receives the heat of the combustion gas generated by the oxidation catalytic reaction in the catalytic reactor 10 and further heats the fuel gas generated in the evaporator 220.

The reformer 240 incorporates a reforming catalyst, reforms the fuel gas supplied from the fuel heat exchanger 230, and generates an anode gas containing hydrogen and the like. The anode gas generated by the reformer 240 is supplied to the fuel cell stack 210.

In the cathode gas passage 203, an air heat exchanger 250 is provided. The air heat exchanger 250 heats the cathode gas (air) flowing through the cathode gas passage 203 by exchanging heat with the combustion gas supplied from the catalytic reactor 10 via the oxidizing gas passage 53. In the present embodiment, an air compressor 203A is installed near the open end of the cathode gas passage 203, and air in the atmosphere as the cathode gas is sucked into the cathode gas passage 203 through the air compressor 203A. The cathode gas is heated when passing through the air heat exchanger 250 and supplied to the fuel cell stack 210.

The catalyst reactor 10 is supplied with anode off-gas discharged from the fuel cell stack 210 through the anode off-gas passage 202 and cathode off-gas discharged through the cathode gas passage 203. Then, the catalytic reactor 10 causes the unburned fuel contained in the anode off gas and the cathode gas to undergo an oxidation catalytic reaction, and discharges the combustion gas to the outside of the fuel cell system 200 via the oxidizing gas passage 53.

Connected to the catalyst reactor 10 are a fuel supply path 51 that branches upstream of the evaporator 220 in the anode gas passage 201 and an air supply path 52 that branches upstream of the air heat exchanger 250 in the cathode gas passage 203. The An injector 20 is provided at a connection point between the fuel supply path 51 and the catalytic reactor 10, and the amount of liquid fuel supplied to the catalytic reactor 10 is controlled by operating the injector 20.

In the catalytic reactor 10, when unburned gas is not supplied from the fuel cell stack 210 such as at the time of startup, the oxidation catalytic reaction does not proceed. Therefore, combustion gas is not generated and heat exchange is not performed in the evaporator 220, the fuel heat exchanger 230, and the air heat exchanger 250. Therefore, the liquid fuel is supplied from the fuel tank 30 to the catalytic reactor 10 to advance the catalytic reaction, and heat exchange is performed in the evaporator 220, the fuel heat exchanger 230, and the air heat exchanger 250. Can do. In this way, warm-up operation can be performed at startup.

In addition, this invention is not necessarily limited to said embodiment, A various change can be made within the range of the technical idea as described in a claim.

Claims (10)

A catalytic reaction system that vaporizes liquid fuel to generate fuel gas and catalyzes the fuel gas,
An injection unit for injecting the liquid fuel;
A first heater that generates the fuel gas by heating and vaporizing the liquid fuel injected from the injection unit;
A catalyst for catalyzing the fuel gas generated by the first heater;
A second heater for heating the catalyst;
A controller that controls a first temperature that is a temperature of the first heater and a second temperature that is a temperature of the second heater;
The catalyst reaction system, wherein the controller controls the first temperature to be lower than the second temperature. The catalytic reaction system according to claim 1,
The catalyst control system, wherein the controller controls the first temperature to be included in a first temperature zone in which a vaporization time of the liquid fuel is shorter than a predetermined time. The catalytic reaction system according to claim 2,
The controller controls the first temperature so that the overall reaction rate of the catalytic reaction system is a temperature range in which the reaction rate is equal to or higher than a predetermined rate, and is included in a second temperature range including the first temperature range. , Catalytic reaction system. The catalytic reaction system according to claim 3,
The controller is configured to be able to control an injection amount of the liquid fuel from the injection unit,
The controller is a catalytic reaction system that reduces the injection amount when the first temperature is lower than a lower limit temperature of the second temperature zone. The catalytic reaction system according to claim 4,
The controller is a catalytic reaction system that increases the injection amount when the first temperature is higher than an upper limit temperature of the second temperature zone. The catalytic reaction system according to any one of claims 1 to 5,
The controller is a catalytic reaction system that controls the second temperature to exceed a temperature at which a catalytic reaction is performed in the catalyst. The catalytic reaction system according to any one of claims 1 to 6,
A housing that houses the first heater, the catalyst, and the second heater;
A catalytic reaction system in which the first heater and the second heater are provided apart from each other in the housing. The catalytic reaction system according to claim 7,
The first heater is provided vertically below the second heater and the catalyst,
The catalytic reaction system, wherein a part of the liquid fuel that has not been vaporized by the first heater remains in an inner bottom portion of the casing on the injection unit side with respect to the first heater in a flow path direction. The catalytic reaction system according to claim 8, wherein
A third heater for heating a part of the inner bottom of the housing;
The catalyst reaction system, wherein the controller controls the temperature of the third heater to be substantially equal to the first temperature. A fuel cell system comprising the catalytic reaction system according to any one of claims 1 to 9,
A reformer for reforming the liquid fuel to generate anode gas;
A fuel cell that generates power by receiving supply of the anode gas and the cathode gas;
The catalytic reaction system arranged adjacent to the reformer so as to be capable of exchanging heat, and causing an oxidation catalytic reaction of the anode off-gas and the cathode off-gas discharged from the fuel cell in the catalyst; and
A fuel cell system that performs a warm-up operation by injecting the liquid fuel from the injection unit when the fuel cell system is activated.

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