JP2002343384A - Fuel cell system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel cell system which maintains its performance. SOLUTION: A controller CTN judges whether the temperature T2 of combustion gas against the supplying volume FMI of fuel, is suitable or not. The judgment is performed by judging whether the volume of heat supplied to a reformer RFM by the combustion gas with a temperature T2 is equivalent to the volume of heat necessary to reform the supplied volume of the fuel or not. When the supplied heat volume exceeds the necessary heat volume, the controller CTN increases the opening degree of a flow rate control valve V3, and makes the flow volume of the air supplied to a combustion device CMB increase, and the temperature of the combustion gas is lowered. When the heat volume is insufficient, the flow volume is lowered and the temperature is increased. Supply of unnecessary heat volume to the reforming device RFM is prevented by controlling the temperature of the combustion gas, and generation of carbon monoxide is restrained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel cell system, and more particularly to a structure for supplying a reformer with energy required for reforming a raw material gas.

[0002]

2. Description of the Related Art In a fuel cell system, a reformer is used to generate a hydrogen-rich gas from a raw material gas, methanol. In the reformer, a reforming reaction is caused by using a catalyst to generate carbon dioxide and hydrogen. The amount of heat required for such a reforming reaction is provided by combustion in a combustor.

As a configuration for applying heat from the combustion chamber to the reforming chamber, there is a configuration disclosed in Japanese Patent Application Laid-Open No. 7-22051. This configuration takes into account a delay in the temperature rise of the reformer with respect to the temperature rise of the combustor, and aims to prevent overheating of the combustor and the reformer that may be caused by the delay. Specifically, the temperature of the upstream portion of the combustion chamber is detected by a temperature sensor, and the low-temperature air flow rate of the fuel gas or the air line of the reheating line is controlled so that this temperature falls within a predetermined temperature range.

[0004]

In the above configuration, overheating of the combustion chamber and the reformer is prevented by maintaining the temperature of the upstream portion of the combustion chamber within a predetermined range, but the generation of carbon monoxide is prevented. There is no explicit point of view of suppressing When the supply amount of the raw material gas is small, the amount of heat given from the combustion chamber becomes excessive, for example, the generation of hydrogen gas is almost completed on the upstream side of the reformer, and the following on the downstream side of the reformer: Causes a chemical reaction.

[0005]

## STR1 ## _{H 2 + CO 2 → CO +} H 2 O carbon monoxide and a fuel electrode catalyst comprising platinum or the like, of the fuel cell stack poisons, there is a problem that significantly reduce its activity. Here, in order to reduce the carbon monoxide in the reformed gas to the permissible concentration of the fuel cell stack, a carbon monoxide removing device is generally installed downstream of the reformer. The generation of reformed gas with a carbon oxide concentration must be avoided.
Therefore, maintaining only the temperature of the upstream portion of the combustion chamber within a predetermined temperature range is insufficient to maintain the performance of the fuel cell stack.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a fuel cell system in which poisoning of a fuel cell stack is avoided and performance is maintained.

[0007]

A first aspect of the present invention provides a reformer (RF) that reforms a raw material gas to generate a hydrogen-rich gas.
M), a fuel cell stack (ST) that generates power by reacting the hydrogen-rich gas and an oxidant, and generates heat required for the reforming by combustion, to the reformer via a heat transfer fluid. The combustion chamber (CMB) to be applied and the heat transfer fluid based on the supply amount (FM1) of the raw material gas so that generation of gas that poisons the fuel cell stack is suppressed during the reforming. A controller (CTL) for controlling the temperature (T2, T3).

In a second aspect based on the first aspect, the control device (CTL) controls the supply amount (F) of the source gas.
M1) decreases, the temperature (T2, T2) of the heat transfer fluid
3) a fuel cell system that reduces

[0009] A third invention is the first or second invention, wherein the temperature (T2, T3) of the heat transfer fluid is an oxidant or a combustion fuel (C) supplied to the combustor (CMB). The control is performed by adjusting the supply amount of at least one of FM3 and FM4).

[0010] A fourth invention is the first or second invention, wherein the combustor (CMB) burns a combustible component in exhaust gas from the fuel cell stack (ST) to produce the necessary component. Generating a heat quantity, the temperature of the heat transfer fluid (T
2) is controlled by adjusting the supply amount of the oxidant to the fuel cell stack (ST).

In a fifth aspect based on the first aspect, the heat transfer fluid includes the combustor (CMB) and the reformer (R).
FM) and the temperature (T2, T3) by mixing with a temperature adjusting fluid whose temperature is different from the heat transfer fluid.
Will be adjusted.

According to a sixth aspect of the present invention, there is provided a reformer (RFM) for generating a hydrogen-rich gas by causing a reforming reaction in a source gas;
A fuel cell stack (ST) for generating electricity by reacting a gas from the reformer with an oxidizing agent, and an energy source for providing energy required for the reforming reaction to the reformer (for example, in the embodiment) And a control device (CNT) that controls the distribution of generation of the reforming reaction in the reformer by providing a difference in the distribution of energy supplied from the energy generation source to the reformer. ).

A seventh invention is the sixth invention, wherein the raw material gas is a gas containing alcohol, and the reformer (RFM) uses oxygen and steam to give the calorific value and perform a catalytic reaction. To generate hydrogen gas from the alcohol.

An eighth invention is the sixth or seventh invention, wherein the energy generation source (CMB) supplies the generated amount of heat to the reformer (RFM) via a heat transfer fluid. It is a heat source, and the temperature of the heat transfer fluid is lower on the downstream side than on the upstream side of the reformer.

A ninth invention is the sixth invention, wherein the heat transfer fluid is branched into a plurality of branches (for example, the duct chambers D1 and D2 of the embodiment), and At least one tributary is connected to the energy source (CM).
B) and the reformer (RFM), the temperature (T3) is lowered by mixing with a temperature adjusting fluid whose temperature is lower than the tributary, and the control device (CNT) The temperature (T3) of the tributary is controlled by manipulating the mixing amount of the temperature adjusting fluid into the tributary.

In the above description, the reference numerals in parentheses illustrate the correspondence with the configuration of the embodiment. These references are not intended to limit the scope of the claims.

[0017]

According to the first aspect of the present invention, the temperature of the heat transfer fluid is controlled by increasing or decreasing the temperature of the heat transfer fluid in accordance with a change in the supply amount of the source gas, for example, as in the second aspect. As a result, the temperature of the reformer is maintained in a temperature range in which generation of a gas such as carbon monoxide is suppressed. As a result, the performance of the fuel cell stack is maintained, and power generation is stabilized.

According to the second aspect of the present invention, when the supply amount of the raw material gas is reduced, the temperature of the heat transfer fluid is lowered, and the configuration of the first aspect of the present invention is easily realized.

According to the third aspect, the combustion amount of the combustor is controlled by adjusting the supply amount of the oxidizing gas or the combustion fuel. Thereby, the configuration of the first invention is easily realized.

According to the fourth aspect, the combustion temperature of the combustor is controlled by adjusting the supply amount of the oxidant to the fuel cell stack. Thereby, the configuration of the first invention is easily realized.

According to the fifth aspect, the temperature of the heat transfer fluid is adjusted by mixing with the fluid having different temperatures between the combustor and the reformer. Thereby, the configuration of the first invention is easily realized.

According to the sixth aspect, by controlling the energy distribution, it is possible to control the place where the reforming reaction occurs in the reformer. Where the energy distribution is low, the generation of by-products due to the application of more energy than necessary for the reforming reaction is avoided.

According to the seventh aspect, generation of carbon monoxide which is a by-product of the catalytic reaction is suppressed. by this,
Poisoning of the fuel cell stack can be effectively avoided.

According to the eighth aspect, when the reforming reaction is completed in the first half of the reformer, it is possible to avoid a disadvantage caused by applying excess heat to the second half.

According to the ninth aspect, the configuration of the sixth aspect can be realized by a simple configuration in which a fluid for temperature adjustment is mixed. Further, by appropriately controlling the mixing amount, the temperature of the heat transfer fluid can be set as desired, and controllability is improved.

[0026]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 In the present embodiment, a configuration is shown in which generation of gas that poisons the fuel cell stack is prevented by minimizing the application of excessive energy to the reformer. In the following,
The reference symbols used for the flow meter and the thermometer are also used to refer to the measurement target. For example, the flow rate (supply amount) of the raw material measured by the flow meter FM1 is the supply amount FM.
Called 1.

FIG. 1 is a schematic view illustrating the fuel cell system of the present embodiment. A liquid raw material is provided to the evaporator EV by the injector IJ1, and the raw material is vaporized. As a raw material, a liquid containing various hydrocarbons such as methanol and water can be used. The raw material gas obtained by vaporization is introduced into the reformer RFM, and a reforming reaction is caused to generate a hydrogen-rich mixed gas. This reformed gas contains carbon monoxide. A carbon monoxide remover RMV is provided downstream of the reformer RFM in order to remove the carbon monoxide to a level lower than the allowable concentration of the fuel cell stack ST.

A pipe is provided between the reformer RFM and the carbon monoxide remover RMV to take in air containing oxygen necessary for oxidizing carbon monoxide to carbon dioxide. A flow control valve V1 for adjusting the flow rate of air is attached to this pipe. Temperature T1 of the mixed gas sent from reformer RFM is measured by thermometer T1. The oxidation of carbon monoxide is an exothermic reaction, and the heat generated is removed by cooling.
Cooling water passes inside the carbon monoxide remover RMV. Note that air or other fluid may flow as a coolant instead of the cooling water.

The reformed gas whose carbon monoxide concentration has been reduced by the carbon monoxide remover RMV is sent to the fuel cell stack ST. Then, oxygen contained in the air taken into the fuel cell stack ST via the pipe to which the flow control valve V2 is attached reacts with the reformed gas to generate electric power. This pipe for taking in air has a flow meter FM
2 is attached, and the controller C
The NT grasps the current flow rate of air and controls the opening of the flow control valve V2 so as to obtain a required flow rate.

The exhaust reformed gas and the exhaust air discharged from the stack ST are sent to a combustor CMB. The amount of heat generated by burning these components covers the amount of heat (energy) required for the reforming reaction in the reformer RMF and the vaporization reaction in the evaporator EV. The gas used for the reforming reaction and the vaporization reaction is discharged out of the system.

In case that the exhaust reformed gas and the exhaust air alone are not sufficient to cause the above reaction, fuel and air for the combustor are added to the combustor CMB so as to compensate for them. The fuel for the combustor is added by the injector IJ2, and the air is added via a pipe fitted with a flow control valve V3. The flow rates of the additional fuel and air are measured by the flow meter FM4 and the flow meter FM3, respectively, and these data are input to the controller CNT.

The controller CNT determines the flow rate of the raw material gas supplied to the reformer RFM from the flow rate of the liquid raw material obtained by the flow meter FM1 mounted upstream of the evaporator EV. Then, the amount of heat that is excess from the amount of heat necessary for the reforming reaction, which can be known from this flow rate, is supplied to the reformer RFM.
, The temperature T2 of the combustion gas sent from the combustor CMB to the reformer RFM is controlled.

The amount of heat supplied from the combustion gas to the reformer RFM is commensurate with the supplied raw material (that is, the amount of heat supplied from the combustion gas ensures the amount of heat required for the raw material reforming reaction itself and the reforming reaction). Is equal to the sum of the minimum amount of preliminary heat required to generate the heat) and the amount of heat transferred to the reformer RFM that is not consumed in the reforming reaction. The generation of carbon is avoided beforehand.

FIG. 2 is a graph illustrating the relationship between the flow rate FM1 of the raw material to be reformed and the temperature T2 of the combustion gas. The amount of heat required for vaporization is proportional to the flow rate FM1 of the raw material. Therefore, as shown in the figure, the temperature T2 of the combustion gas must be increased as the flow rate FM1 of the raw material increases. The controller CNT knows the appropriate temperature of the combustion gas based on the flow rate of the raw material obtained from the flow meter FM1 based on the graph of FIG. Then, the combustion amount of the combustor CMB is calculated from the appropriate temperature, and control is performed. Whether the control is successful or not can be known by the thermometer T2 attached to the pipe P1 through which the fuel gas passes between the combustor CMB and the reformer RFM. When the temperature T2 is low, the controller CNT increases the combustion amount of the combustor CMB or decreases the cooling amount, and when the temperature T2 is high, decreases the combustion amount or increases the cooling amount to increase the temperature of the combustion gas. Set T2 to an appropriate one.

Controlling the temperature of the combustion gas with respect to the flow rate of the raw material can be performed, for example, based on the following equation.

[0036]

(Equation 1) The meanings of the symbols used in Equation 1 are as follows.

Tg: Combustion gas temperature Tlow ≦ Tg ≦ High is satisfied Tlow: Lower limit of combustion gas temperature, High: Upper limit of combustion gas temperature q1: Heat absorption required for reforming q2: Heat dissipation to reformer q3: Sensible heat correction value of reforming fuel X: Endothermic amount required for reforming per unit fuel flow Qi: Raw material flow Qg: Combustion gas flow Cpg: Specific heat of combustion gas Ti: Reforming fuel temperature t: Temperature correction Here, the specific heat Cpg changes as the composition changes, and the flow rate Qg
Also change during the control process. Therefore, it is necessary to repeatedly calculate the temperature T based on Equation 1. Equation 1 is a basic equation for determining the temperature Tg of the combustion gas. In order to actually determine the temperature Tg of the combustion gas, the performance of each reactor must be considered. Therefore, the heat exchange capacity of the reactor,
Alternatively, more appropriate control can be performed by adding a new correction coefficient to Equation 1 according to considerations such as the reforming capacity, modifying a part of Equation 1, and using a map.

There are various options for controlling the amount of combustion as follows. First, the combustion amount is set as desired by increasing or decreasing the supply amount of at least one of the additional combustor fuel supplied by the injector IJ2 and the air whose intake is controlled by the flow control valve V3. Is mentioned. Specifically, the fuel supply amount may be reduced when the combustion amount is to be reduced, and may be increased when the fuel supply amount is to be increased. Normally, a larger amount of air is supplied than is necessary to burn all the fuel, and the amount of air is increased when the temperature T2 of the combustion gas is to be decreased, and is decreased when the temperature T2 of the combustion gas is to be increased. You can do it.

FIG. 3 is a flowchart illustrating a processing procedure for controlling the supply amount of the combustor fuel or the combustor air. First, in step S1, the flow meter F of FIG.
The supply amount FM1 of the raw material is measured using M1. In the following step S2, the temperature T2 of the combustion gas is measured using the thermometer T2. Next, in step S3,
Whether the temperature T2 of the combustion gas is appropriate for the supply amount FM1 of the raw material is determined based on the graph of FIG. If determined to be appropriate (YES), step S
At 4, the current operating state is maintained.

On the other hand, if it is determined that the fuel amount is not appropriate (NO), the amount of fuel (FM4) or the amount of air FM3 supplied to the combustor is adjusted in step S6a. In steps S1 and S2, the supply amount FM1 of the raw material and the temperature T2 of the combustion gas at the adjusted combustion amount are measured again. In this way, in step S3, the temperature T
Step S6a and the processing of steps S1 to S3 are repeated until it is determined that 2 is appropriate. The reason why step S1 is performed after step S6a is to consider a case where the supply amount FM1 of the raw material changes before the temperature T2 of the combustion gas changes from inappropriate to appropriate.

In step S5 following step S4, it is determined whether the operation is continued. In the case of continuation, "YES" is determined, and the process returns to step S1.
If not to continue, “NO” is determined and the process ends.

As a second alternative to the first alternative illustrated in FIG. 3, the amount FM2 of air supplied to the fuel cell stack ST in FIG. 1 is increased or decreased according to a desired combustion temperature. Can be

FIG. 4 is a flowchart exemplifying a processing procedure for changing the supply amount of air to the fuel cell stack ST in FIG. 1 to set the combustion gas temperature T2 as desired. In the procedure shown in FIG. 3, the processing in step 6a in FIG.
The processing is replaced with the processing of b, and the other parts are the same. In step S6b, the air supply amount F to the stack ST is determined according to the results of steps S1 to S3.
Adjust M2. Specifically, when it is desired to increase the temperature T2 of the combustion gas, the supply amount FM2 of air to the stack ST is decreased, and when it is desired to decrease, the supply amount FM2 is increased. Thus, the amount of air supplied to the combustor CMB is changed to change the combustion temperature of the combustor CMB. In this way, the temperature T2 of the combustion gas is set as in the example of FIG.

By controlling the combustion temperature of the combustor CMB as described above, the temperature T2 of the combustion gas supplied to the reformer RFM can be set as desired.
However, it is also possible to change the temperature T2 of the combustion gas while keeping the combustion temperature constant. For example, air having different temperatures may be mixed with the combustion gas.

FIG. 5 is a schematic view illustrating a configuration in which air is mixed into the combustion gas to change the temperature. The configuration in FIG. 5 is obtained by newly adding an air mixing unit to the configuration in FIG. 1, and the configuration of a portion that is not related thereto is the same as that in FIG. 1. Hereinafter, the differences will be described.

A new pipe P2 is connected to the pipe P1 through which the combustion gas passes between the combustor CMB and the reformer RFM. A flow meter FM5 and a flow control valve V4 are attached to the new pipe P2, and a desired amount of air is mixed into the combustion gas by the controller CNT. Further, a thermometer T2 is attached to the pipe P1 on a side closer to the reformer RFM than a portion where air is mixed. With such a configuration, the controller CNT controls the temperature T2 of the combustion gas after the lower temperature air is mixed.
Is measured, and if there is a difference between the appropriate temperature and the actual temperature T2, the mixed amount of air is changed to eliminate the difference. Specifically, when the actual temperature T2 is higher than an appropriate temperature, the amount of air mixed is increased, and when the actual temperature T2 is low, the air mixing amount is decreased.

FIG. 6 is a flowchart exemplifying a processing procedure for controlling the temperature of the combustion gas by adjusting the mixed amount of air. In the processing procedure of FIG. 6, the processing of step S6a of FIG. 3 is replaced with the processing of step S6c, and the other parts are the same. In step S3, the controller CNT of FIG.
When it is determined that the temperature T2 of the combustion gas is not appropriate, the supply amount FM5 of the air mixed with the combustion gas is adjusted in step S6c. Thereafter, the processing of steps S1 to S3 and step S6c is repeated until "YES" is determined in step S3, and the temperature T2 of the combustion gas becomes appropriate.

In addition, it is also possible to lower the temperature by removing heat from the combustion gas by the cooling water. In this case, the temperature T2 of the combustion gas can be set as desired by adjusting the temperature or flow rate of the cooling water.

The combustion gas set to a desired temperature by the above various methods is supplied to the reformer RFM. FIG. 7 is a cross-sectional perspective view illustrating the configuration of the reformer RFM. In the reformer RFM, the reforming catalyst layers CL1 to CL3 in which the raw material gas (reformed gas) flows and the combustion gas layers GL1 to GL2 in which the combustion gas flows are alternately stacked to efficiently transfer heat. ing. In order to further increase the efficiency of heat transfer and improve the reforming efficiency, plate fins are provided inside each layer to increase the contact area with the gas.

The raw material gas sent to the reforming catalyst layers CL1 to CL3 receives heat from the combustion gas sent to the combustion gas layers GL1 to GL2, and is converted into a hydrogen-rich gas by a reforming reaction by the reforming catalyst. Quality. Here, the fins in adjacent layers are orthogonal to each other as shown, and the reformer RFM is a cross-flow type in which the flow of the raw material gas (reformed gas) and the flow of the combustion gas are orthogonal to each other. It has become. In addition, such a cross-flow type configuration also has an advantage that it is possible to make large ducts for feeding the raw material gas and the combustion gas to the reforming catalyst layers CL1 to CL3 and the combustion gas layers GL1 to GL2, respectively. This results in a reduced pressure drop in the direction of flow.

Further, as described above, the combustion gas temperature T2
Is suppressed by the controller CTL (FIGS. 1 and 5) to such an extent that the reforming reaction occurs not only on the upstream side of the reformer RFM but also on the whole.

By controlling the temperature T2 as described above, the reforming reaction occurs uniformly in the reformer RFM. Therefore, it is possible to avoid a situation in which the reforming reaction is completed for almost all of the raw material gas on the upstream side of the reformer RFM and the calorific value is left on the downstream side, thereby generating carbon monoxide. Is done. Deterioration of the performance of the fuel cell stack ST due to poisoning by carbon monoxide is avoided, and efficient power generation can be performed over a long period of time. Further, the heating of the reforming catalyst due to the surplus heat on the downstream side of the reformer RFM is also avoided.

With the above configuration, even if the supply amount FM1 of the raw material is changed according to the power generation amount of the fuel cell stack ST required by the load, the amount of combustion or the amount of air to be mixed in is adjusted. It is possible to respond without reducing the quality efficiency.

Embodiment 2 In the first embodiment,
A configuration is shown in which the overall temperature of the combustion gas is adjusted so that the reforming reaction occurs uniformly in the reformer RFM. On the other hand, the present embodiment shows a configuration in which the temperature of the combustion gas is partially changed.

FIG. 8 is a schematic view illustrating the fuel cell system of the present embodiment. The fuel cell system shown in FIG.
In the fuel cell system of FIG. 5, a duct D for feeding combustion gas to the reformer RFM is branched into two as shown. FIG. 9 is a schematic view illustrating the cross-sectional structure of the duct D. As illustrated, the duct D has a duct chamber D1 and a duct chamber D2 by being branched from the middle. The duct chamber D2 is provided with a thermometer T3. Then, the temperature T3 in the duct chamber D2 is detected by the controller CNT in FIG. further,
In FIG. 5, the pipe P2 connected to the pipe P1 and the flow meter FM5 and the flow control valve V4 attached thereto are connected to one room of the duct (the duct chamber D2 in this example) in the configuration of FIG. Installed. Structures other than those relating to these are shown in FIGS.
Common to each configuration. Along with such a configuration change, the processing procedure of the controller CNT is also modified from the processing procedure of FIG. Hereinafter, differences will be described.

As illustrated in FIG. 9, air is mixed into the combustion gas in the duct chamber D2 by the flow control valve V4 in FIG. Thereby, the temperature T3 in the duct chamber D2
And the density of the amount of heat given to the reformer RFM increases on the upstream side of the raw material gas and decreases on the downstream side. It is a feature of the present embodiment that the total amount of heat provided to the reformer by the upstream and downstream combustion gases is suppressed to a level necessary for reforming the raw material gas by the supplied amount.

FIG. 10 shows a controller C according to the present embodiment.
It is a flowchart which illustrates the processing procedure of NT. In the processing procedure of FIG. 6, steps S2, S3, and S6c of the processing procedure of FIG. 6 correspond to steps S2d, S3d, and S6d of the present embodiment, respectively.
And the other parts are the same.
First, in step S1, the controller CNT of FIG. 8 measures the supply amount FM1 of the raw material using the flow meter FM1. Next, in step S2d, the temperature of the combustion gas is measured at a total of two points of the pipe P1 and the duct chamber D2 using the thermometer T2 and the thermometer T3 to obtain the temperature T2 and the temperature T3. Here, the temperature T2 measured in the pipe P1 can be used as the temperature of the duct chamber D1.

Next, in step S3d, it is determined whether the temperature T3 of the duct chamber D2 is appropriate for the supply amount FM1 of the raw material and the temperature T2 of the combustion gas in the duct chamber D1. How to determine whether or not it is appropriate will be described below. First, the controller CNT determines the amount of heat given to the source gas by the combustion gas flowing into the duct chamber D1. Then, when this calorie is subtracted from the calorie necessary for reforming the raw material for the flow rate FM1 measured in step S1, the remaining calorie is found. The temperature T3 in the duct chamber D2 is determined so that the insufficient amount of heat is given by the mixed gas of the combustion gas in the duct chamber D2 and the mixed air. By comparing the ideal temperature in the duct chamber D2 with the actual measured value T3, it can be determined whether the temperature is appropriate. In addition, since the temperature T3 in the duct chamber D2 is uniquely determined at least from the raw material supply amount FM1 and the combustion gas temperature T2, it is quicker to input a calculation formula into the controller CNT in advance.

If it is determined in step S3d that it is appropriate (YES), the above-described processing from step S4 is performed. On the other hand, if it is determined that it is not appropriate (NO), the process proceeds to step S6d. In step S6d, the air supply amount FM5 to the duct chamber D2 is adjusted by increasing the measured air temperature if the measured temperature is higher than the ideal temperature and decreasing the measured air temperature if the measured temperature is lower than the ideal temperature. Then, the processes of steps S1 to S3d and step S6d are repeated until the temperature is determined to be appropriate in step S3d.

As described above, by making the temperatures of the duct chamber D1 and the duct chamber D2 illustrated in FIG. 9 different from each other, the reforming reaction is actively caused on the upstream side of the higher temperature reformer RFM. On the downstream side where the temperature is low, it can be caused slowly. That is, by providing a difference in the amount of heat applied between the upstream side and the downstream side, the generation density of the reforming reaction is changed between the upstream side and the downstream side. Also in this configuration, the amount of heat that is excessive with respect to the supply amount FM1 of the raw material is not supplied to the reformer RFM, and disadvantages such as generation of carbon monoxide are avoided as in the first embodiment. Is done. On the other hand, when the load increases and the supply amount of the raw material is increased, the amount of air mixed into the downstream combustion gas is reduced, and the reformer RFM performs reforming without lowering the reforming efficiency. In response to the increase in the load, the mixed amount of the air eventually becomes “0”, and the entire reformer RFM is used for the reforming without any excess.

In the above description, the duct chamber D on the downstream side
2, the temperature is controlled by mixing air into the upstream duct chamber D1 while maintaining the temperature in the downstream duct chamber D2 as it is.
Only air may be mixed. Also in this case, the reformer RF
The objective of not giving extra heat to M can be achieved. In this case, a reforming reaction mainly occurs on the downstream side of the reformer RFM. It is also possible to adopt a configuration in which air is independently mixed into both duct chambers D1 and D2 to control the temperature independently.
Further, similarly to the first embodiment, the amount of heat may be taken by cooling water instead of mixing with air. In addition, the number of duct chambers is not limited to two, and may be three or more.

In this embodiment, by determining how much air is mixed into a part of the combustion gas, reforming is performed using the entire reformer RFM, or one of the reformers RFM is performed. It is possible to determine whether to perform reforming mainly by using a part. It can be said that such control corresponds to adjusting the substantial capacity (size) of the reformer RFM according to the raw material supply amount FM1. The advantage of the present embodiment is that the temperature of the part of the catalyst that performs the reforming reaction other than the part necessary for the raw material for the supply amount of FM1 can be kept low and the catalyst in this part can be rested. Configuration has.

Although the present invention has been described with reference to the embodiment, the technical scope of the present invention is not limited to the scope described in the above embodiment. Various changes or improvements can be added to the above embodiment. It should be noted that such modified or improved embodiments may be included in the technical scope of the present invention.
It is clear from the description of the claims.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating an example of a configuration of a fuel cell system according to Embodiment 1.

FIG. 2 is a graph illustrating a method of obtaining an appropriate combustion gas temperature T2 with respect to a raw material flow rate FM1.

FIG. 3 is a flowchart illustrating a first example of a processing procedure of the controller CNT according to the first embodiment;

FIG. 4 is a flowchart illustrating a second example of the processing procedure of the controller CNT according to the first embodiment.

FIG. 5 is a schematic diagram showing another example of the configuration of the fuel cell system according to the first embodiment.

FIG. 6 is a flowchart illustrating a third example of the processing procedure of the controller CNT according to the first embodiment.

FIG. 7 is a cross-sectional perspective view illustrating the structure of a reformer RFM.

FIG. 8 is a schematic diagram illustrating an example of a configuration of a fuel cell system according to Embodiment 2.

FIG. 9 is a schematic view illustrating the cross-sectional structure of a duct D.

FIG. 10 is a flowchart illustrating a processing procedure of a controller CLT according to the second embodiment;

[Explanation of symbols]

CMB Combustor CTL controller D Duct D1, D2 Duct chamber FM1 to FM5 Flow meter and flow rate RFM reformer ST Fuel cell stack S1 to S5, S2d, S3d, S6a to S6d Steps T1 to T3 Thermometer and temperature

Claims (9)

[Claims] 1. A reformer that reforms a raw material gas to generate a hydrogen-rich gas, a fuel cell stack that generates power by reacting the hydrogen-rich gas and an oxidant, and burns a heat amount required for the reforming And a combustor that is generated and applied to the reformer via a heat transfer fluid, so that generation of a gas that poisons the fuel cell stack is suppressed during the reforming. A control device for controlling the temperature of the heat transfer fluid based on a supply amount. 2. The fuel cell system according to claim 1, wherein the control device is configured to reduce the supply amount of the source gas.
A fuel cell system for reducing the temperature of the heat transfer fluid. 3. The fuel cell system according to claim 1, wherein the temperature of the heat transfer fluid is at least one of an oxidant and a combustion fuel supplied to the combustor. A fuel cell system controlled by adjusting one of the supply amounts. 4. The fuel cell system according to claim 1, wherein the combustor burns a combustible component in an exhaust gas from the fuel cell stack to produce the required heat quantity. And wherein the temperature of the heat transfer fluid is controlled by adjusting a supply of the oxidant to the fuel cell stack. 5. The fuel cell system according to claim 1, wherein the heat transfer fluid is provided between the combustor and the reformer,
A fuel cell system in which the temperature is adjusted by mixing the temperature with a temperature adjusting fluid different from the heat transfer fluid. 6. A reformer for generating a hydrogen-rich gas by causing a reforming reaction in a raw material gas; a fuel cell stack for generating electricity by reacting a gas from the reformer with an oxidant; An energy generation source for providing energy required for the reaction to the reformer; and a difference in distribution of energy supplied from the energy generation source to the reformer, whereby the reforming of the reforming reaction is performed. And a control device for controlling the distribution of generation in the fuel cell. 7. The fuel cell system according to claim 6, wherein the raw material gas is a gas containing alcohol, and the reformer uses oxygen and water vapor to give the calorific value to cause a catalytic reaction. Thereby producing hydrogen gas from the alcohol. 8. The fuel cell system according to claim 6, wherein the energy generating source supplies the generated amount of heat to the reformer via a heat transfer fluid. Wherein the heat transfer fluid has a lower temperature on the downstream side than on the upstream side of the reformer. 9. The fuel cell system according to claim 6, wherein the heat transfer fluid is branched into a plurality of branches, and at least one of the branches is connected to the energy generating source. Between the reformer, the temperature is lowered by being mixed with a fluid for temperature adjustment whose temperature is lower than that of the tributary, and the control device is configured to control the mixing amount of the fluid for temperature adjustment into the tributary. A fuel cell system for controlling the temperature of the tributary by operating the fuel cell.