JP5598655B2 - Fuel cell system - Google Patents

Description

  The present invention relates to a fuel cell system, and more particularly to a fuel cell system including a reformer and a solid oxide fuel cell (SOFC).

  Patent Document 1 below describes a combined power generation facility including an SOFC supplied with a reformed gas reformed by a reformer and an internal combustion engine driven by the off-gas of the SOFC. In this combined power generation facility, power is generated by SOFC, and the internal combustion engine is driven to further generate power. Moreover, the water | moisture content in off gas is discharged | emitted by the drainage drain.

JP 2008-180131 A

  By the way, in a reformer, in order to decompose | disassemble the hydrocarbon compound in fuel gas and to produce | generate hydrogen, for example, water vapor | steam is added to fuel gas under the high temperature of 600-800 degreeC. In installation-type facilities such as a power plant, reforming water used as steam in a reformer can be easily obtained from tap water, for example.

  However, in a fuel cell system mounted on an electric vehicle, it is difficult to supply reforming water from the outside during traveling. For this reason, it is necessary to mount a water tank for storing reforming water in the electric vehicle. However, when a water tank is mounted on an electric vehicle, the water tank occupies a large volume in the electric vehicle, and the reforming water stored in the water tank increases the weight of the electric vehicle.

  Accordingly, an object of the present invention is to provide a fuel cell system capable of self-supplying at least a part of reforming water used as water vapor in a reformer.

In order to achieve the above object, a fuel cell system of the present invention includes a reformer that generates a reformed gas containing hydrogen by adding water vapor to a fuel gas containing a hydrocarbon compound, and reforming from the reformer. A solid oxide fuel cell (SOFC) to which gas is supplied; an internal combustion engine that sucks off-gas discharged from the solid oxide fuel cell as part of the fuel; and an exhaust gas discharged from the internal combustion engine; An exhaust gas heat exchanger that performs heat exchange between at least one of the reformer and the solid oxide fuel cell to heat at least one of the reformer and the solid oxide fuel cell; First collecting means for collecting water from the exhaust gas cooled by the exhaust gas heat exchanger, and using the water collected by the first collecting means as water vapor in the reformer , The exhaust gas heat exchanger A first passage that is provided in both the reformer and the solid oxide fuel cell and guides the exhaust gas that exchanges heat with the reformer, and the first passage that guides the exhaust gas that exchanges heat with the solid oxide fuel cell. And the first collecting means is provided on the downstream side of the joining portion where the first passage and the second passage join .

  The high-temperature exhaust gas discharged from the internal combustion engine contains water generated by combustion in the internal combustion engine. When the exhaust gas passes through the exhaust gas heat exchanger, the exhaust gas is cooled and water in the exhaust gas condenses. The condensed water is collected by the first collecting means and used as water vapor in the reformer. Thereby, at least a part of the water for reforming used as steam in the reformer can be self-supplied.

Further , water can be collected by one collecting means from the exhaust gas exchanged with the reformer and from the exhaust gas exchanged with the solid oxide fuel cell. As a result, a collecting means for collecting water from the exhaust gas exchanged with the reformer and a collecting means for collecting water from the exhaust gas exchanged with the solid oxide fuel cell were separately provided. The configuration of the fuel cell system can be simplified as compared to the case, and the cost of the fuel cell system can be reduced.

  In the present invention, preferably, an off-gas heat exchanger that heats the reformer by exchanging heat between the off-gas discharged from the solid oxide fuel cell and the reformer; and And a second collecting means for collecting water from the off-gas cooled by the off-gas heat exchanger, and the water collected by the second collecting means is used as steam in the reformer.

The off-gas discharged from the SOFC contains water produced by the reaction of hydrogen in the reformed gas and oxygen in the air. When the off gas passes through the off gas heat exchanger, the off gas is cooled and water in the off gas condenses. The condensed water is collected by the second collecting means and used as water vapor in the reformer. Thereby, in addition to the water collected by the first collecting means, the water collected by the second collecting means can also be used as the reforming water. As a result, more reforming water can be self-sufficient.

Moreover, in this invention, Preferably, the said 1st and 2nd collection means has a common water tank which stores the collected water.
In this way, by providing a common water tank, a water tank for storing the water collected by the first collecting means and a water tank for collecting the water collected by the second collecting means are separately provided. Therefore, the configuration of the fuel cell system can be simplified and the cost of the fuel cell system can be reduced.

In the present invention, preferably, the collected water is supplied to the reformer and heated with the heat of the reformer to form steam.
During operation of the fuel cell system, the reformer is heated to a high temperature of several hundred degrees Celsius. For this reason, if the collected water is supplied to the reformer, the water evaporates to become steam. As described above, by using the heat of the reformer, it is possible to generate water vapor without providing a heating means for converting the collected water into water vapor. As a result, the configuration of the fuel cell system can be simplified and the cost of the fuel cell system can be reduced as compared with the case where the collected heating means is separately provided.

  According to the fuel cell system of the present invention, at least a part of the reforming water used as water vapor in the reformer can be supplied by itself.

1 is a schematic diagram showing a basic configuration of a fuel cell system according to a first embodiment of the present invention. It is a block diagram which shows the input-output relationship of the control unit of the fuel cell system by 1st Embodiment of this invention. It is a flowchart which shows the basic control of the fuel cell system by 1st Embodiment of this invention. It is the schematic which shows the basic composition of the fuel cell system by 2nd Embodiment of this invention.

Hereinafter, embodiments of a fuel cell system of the present invention will be described with reference to the accompanying drawings.
First, the configuration of the fuel cell system according to the first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a schematic diagram showing the basic configuration of the fuel cell system according to the first embodiment.

  The fuel cell system according to the first embodiment is a power source for driving an electric vehicle, and basically adds a water vapor to a fuel gas containing a hydrocarbon compound to generate a reformed gas containing hydrogen. 1, an SOFC 2 to which the reformed gas generated by the reformer 1 is supplied, and an engine 3 as an internal combustion engine that sucks off-gas discharged from the SOFC 2 as a part of the fuel.

  In the reformer 1, for example, by adding water vapor to a fuel gas containing a hydrocarbon compound such as methane at a high temperature of 600 to 800 ° C., the hydrocarbon compound is decomposed to generate hydrogen. In the present embodiment, liquefied petroleum gas (LPG) is used as the fuel gas.

  In FIG. 1, the path of the fuel gas supplied to the reformer 1 is indicated by a solid line 10a. The amount of fuel gas supplied is adjusted by the opening of the fuel gas control valve 8a. Moreover, each gas path shown in FIG. 1 is formed by piping not shown.

  Further, the reformer 1 performs heat exchange between the off-gas discharged from the SOFC 2 and the reformer 1 to heat the reformer 1 and the engine 3 discharges the heat. A first exhaust gas heat exchanger 5 that heats the reformer 1 by exchanging heat between the exhaust gas and the reformer 1 is provided. Each of these heat exchangers 4 and 5 can adopt any suitable structure. For example, as the heat exchangers 4 and 5, the periphery of the reformer 1 may be covered with a jacket through which exhaust gas and off gas are separately passed, or a plurality of pipes through which exhaust gas and off gas are separately passed may be It may be provided inside.

The reformed gas reformed by the reformer 1 is supplied to the SOFC 2. Air (Air) is also supplied to the SOFC 2.
In FIG. 1, the path of the reformed gas supplied from the reformer 1 to the SOFC 2 is indicated by a solid line 10b, and the path of the air supplied to the SOFC 2 is indicated by a broken line 11a.

  The SOFC 2 includes a fuel electrode (anode) 2a and an air electrode (cathode) 2b. The reformed gas generated by the reformer 1 is supplied to the fuel electrode 2a. Air is supplied to the air electrode 2b.

  In the SOFC 2, hydrogen in the reformed gas supplied to the fuel electrode 2 a and oxygen in the air supplied to the air electrode 2 b react to generate water, and a power generation reaction that generates electricity is performed. . Electricity generated by the power generation reaction is sent to a secondary battery (not shown) connected to the ceramic electrode of each of the fuel electrode 2a and the air electrode 2b and a drive motor (not shown) of the electric vehicle.

  In addition, the SOFC 2 is provided with an exhaust gas heat exchanger 6 that performs heat exchange with the exhaust gas discharged from the engine 3 to heat the SOFC 2. The exhaust gas heat exchanger 6 can employ any suitable structure. For example, as the exhaust gas heat exchanger 6, the periphery of the SOFC 2 may be covered with a jacket through which the exhaust gas passes, or a plurality of pipes through which the exhaust gas passes may be provided inside the SOFC 2.

From SOFC 2, a gas containing water, unreacted hydrogen, unreformed hydrocarbon compound, and carbon dioxide generated in the power generation reaction is discharged as off-gas. The off gas discharged from the SOFC 2 is guided to the off gas heat exchanger 4 provided in the reformer 1. Further, the reformer 1 is heated and the offgas is cooled by the offgas heat exchanger 4.
In FIG. 1, the path of off gas led from the fuel electrode 2a of the SOFC 2 to the off gas heat exchanger 4 is shown by a solid line 10c, and the path of off gas led from the air electrode 2b of the SOFC 2 to the off gas heat exchanger 4 is shown by a broken line 11b.

The off gas that has passed through the off gas heat exchangers 4 and 5 is guided to the engine 3.
In FIG. 1, an offgas path guided from the offgas heat exchanger 4 to the engine 3 is indicated by a solid line 10 d, and an offgas path guided from the offgas heat exchanger 5 to the engine 3 is indicated by a broken line 11 c.

  By the way, the off-gas discharged from the SOFC 2 contains water generated by the reaction of hydrogen in the reformed gas and oxygen in the air. When the off gas passes through the off gas heat exchanger 4, the off gas is cooled by the off gas heat exchanger 4, and water in the off gas condenses.

  Therefore, a collecting means 7a for collecting water from the offgas is provided in the middle of a path 10d for guiding the offgas from the offgas heat exchanger 4 to the engine 3. The collecting means 7a is composed of a drain 71 for discharging water condensed on the inner wall of the pipe of the off-gas passage 10d from the pipe, and a common water tank 72 for storing water discharged from the drain 71.

  In addition, the dimension shape of the drain 71 and the volume shape of the common water tank 72 can be made into any suitable thing. In this embodiment, the drain 71 and the common water tank 72 constitute the collecting means 7a. However, the structure of the collecting means 7a is not limited to this, and any suitable means for collecting water from off-gas. A configuration can be employed. For example, in addition to the drain 71 and the common water tank 72, a cooling means for further cooling off-gas may be provided.

  The water collected by the collecting means 7a is used as steam in the reformer 1. Specifically, the water stored in the common water tank 72 is supplied to the reformer 1 through the pipe 74 and is heated by the heat of the reformer 1 to become steam. In this way, the reforming water used as the steam for the reforming reaction in the reformer 1 can be self-supplied.

  As the engine 3 to which the off gas is supplied, an internal combustion engine having an intake / exhaust cycle can be used. For example, a reciprocating engine may be employed as the engine 3 or a rotary engine may be employed. In FIG. 1, the example of the reciprocating engine provided with the piston 33 is shown typically. When the engine 3 is driven as an internal combustion engine, air (Air) and fuel (LPG) are supplied to the intake port 31 of the engine 3 together with off-gas in order to optimize combustion in the engine 3. The air supply amount is controlled by the air control valve 8b, and the fuel supply amount is controlled by the fuel control valve 8c.

  By using the off gas as a part of the fuel in the engine 3, unreacted hydrogen contained in the off gas can be burned, and unreformed hydrocarbon compounds contained in the off gas can also be burned. In this way, by burning off-gas in the engine 3, it is possible to avoid releasing highly flammable hydrogen gas into the atmosphere, and to reduce exhaust gas purification by reducing hydrocarbon compounds in the off-gas. Can be planned.

  The engine 3 does not directly drive the wheels of the vehicle, but causes the generator to generate electric power that is a power source of the drive motor of the vehicle. For this reason, the engine 3 functions not only as a power source for running the vehicle but also as a blower (pump) for sending the reformed gas and air to the SOFC 2. Specifically, the engine 3 sucks off gas from the intake port 31 in the intake cycle. As a result, the reformed gas is sucked from the reformer 1 at the fuel electrode 2a of the SOFC 2, and the air is sucked at the air electrode 2b. Further, in the reformer 1, the fuel gas is sucked. Therefore, the fuel cell system according to the present embodiment does not require a blower for sending the fuel gas to the reformer and sending the reformed gas to the SOFC and a blower for sending the air to the SOFC.

  The piston rod 34 of the engine 3 is connected to a motor / generator 35. As a result, the engine 3 can also drive off-gas as part of the fuel as an internal combustion engine and generate power supplementarily by the motor / generator 35. In addition, the piston 33 of the engine 3 can be moved by driving the motor / generator 35 as a motor by using electricity charged in the secondary battery.

  The exhaust gas exhausted from the exhaust port 32 of the engine 3 is guided to one or both of the exhaust gas heat exchanger 5 of the reformer 1 and the exhaust gas heat exchanger 6 of the SOFC 2. Then, the exhaust gas heat-exchanged by the exhaust gas heat exchanger 5 of the reformer 1 is exhausted through the first passage 12a. Further, the exhaust gas heat-exchanged by the SOFC 2 exhaust gas heat exchanger 6 is exhausted through the second passage 12b.

  FIG. 1 shows an example in which the exhaust path control valve 8 d provided on the exhaust path is opened and the exhaust path control valve 8 e is closed to guide the exhaust gas to the exhaust gas heat exchanger 5 of the reformer 1. For this reason, in FIG. 1, a path leading the exhaust gas from the exhaust port 32 to the exhaust gas heat exchanger 5 of the reformer 1 is indicated by a thick line 12, and the exhaust gas branched in the middle of this path is the exhaust gas heat of the SOFC 2. A path leading to the exchanger 6 is indicated by a two-dot chain line. The first passage 12a is indicated by a thick line, and the second passage 12b is indicated by a two-dot chain line.

  When the fuel cell system is started, in order to warm up the SOFC 2, the exhaust path control valve 8 d is closed and the exhaust path control valve 8 e is opened to guide the exhaust gas to the exhaust gas heat exchanger 6 of the SOFC 2. Alternatively, both the exhaust path control valves 8d and 8e may be opened to guide the exhaust gas to both the exhaust gas heat exchanger 5 of the reformer 1 and the exhaust gas heat exchanger 6 of the SOFC 2.

  The high-temperature exhaust gas discharged from the engine 3 contains water generated by combustion in the engine 3. When the exhaust gas passes through the exhaust gas heat exchanger 5 provided in the reformer 1 or the exhaust gas heat exchanger 6 provided in the SOFC 2, the exhaust gas is cooled and water in the exhaust gas condenses.

  Therefore, a collecting means 7b for collecting water from the exhaust gas is provided on the downstream side of the joining portion 12c where the first passage 12a and the second passage 12b join. The collecting means 7b is composed of a drain 73 for discharging water condensed on the inner walls of the pipes of the first passage 12a and the second passage 12b from the pipe, and a common water tank 72 for storing water discharged from the drain 73. The

Since the collecting means 7b for collecting water from the exhaust gas is provided on the downstream side of the joining portion 12c where the first passage 12a and the second passage 12b join, the exhaust means exchanged heat with the reformer 1 can also be used. The water can also be collected by the single collecting means 7b from the exhaust gas heat-exchanged with the SOFC2.
The collecting means for collecting the exhaust gas water heat-exchanged with the reformer 1 and the collecting means for collecting water from the exhaust gas heat-exchanged with the SOFC 2 may be provided separately.

Furthermore, the collecting means 7a for collecting water from the off gas and the collecting means 7b for collecting water from the exhaust gas have a common water tank 72. As a result, the configuration of the fuel cell system can be simplified and the cost can be reduced.
In addition, you may provide a water tank separately in the collection means 7a which collects water from offgas, and the collection means 7b which collects water from exhaust gas.

  In addition, the size and shape of the drain 73 can be arbitrarily selected. In this embodiment, the drain 73 and the common water tank 72 constitute the collecting means 7b. However, the structure of the collecting means 7b is not limited to this, and any suitable suitable for collecting water from the exhaust gas. Can be adopted. For example, in addition to the drain 73 and the common water tank 72, a cooling means for further cooling off-gas may be provided.

  The water collected by the collecting means 7a and 7b is used as steam in the reformer 1. Thereby, in addition to the water collected from the off gas by the collecting means 7a, the water collected from the exhaust gas by the collecting means 7b can also be used as the reforming water. As a result, more reforming water can be self-sufficient.

  Ideally, all the water for reforming should be self-sufficient. In that case, a system for supplying reforming water to the reformer from the outside can be omitted. The common water tank 72 may be replenished with water from the outside, and only a part of the reforming water may be supplied by itself. Even when only a part of the reforming water is self-supplied, the amount of water replenished from the outside can be reduced and the capacity of the common water tank 72 can be reduced as compared with the case where no reforming water is self-supplied. can do.

Opening and closing of each valve is controlled by a control unit 9 as control means.
FIG. 2 is a block diagram showing the input / output relationship of the control unit 9. As shown in FIG. 2, the control unit 9 includes an ignition switch (IG SW) on information 91, an engine speed 92, a vehicle speed 93, an accelerator opening 94, and a state of charge of the secondary battery. : SOC) 95, SOFC temperature 96 and reformer temperature 97 information are input. These pieces of information are detected by sensors (not shown). In addition, the control unit 9 controls not only the opening / closing and opening of each valve but also the operation of the motor / generator 35.

Next, basic control during operation of the fuel cell system by the control unit 9 will be described with reference to the flowchart of FIG.
First, information on the vehicle speed, the accelerator opening, and the SOC of the secondary battery is read into the control unit 9 (S31).

Next, electric power required for traveling is calculated from the vehicle speed and the accelerator opening (S32).
Next, the charging power to be generated by the SOFC 2 is calculated from the SOC of the secondary battery (S33).

Next, the amount of fuel and the amount of air to be supplied to the SOFC 2 are calculated according to the calculated charging power (S34).
Next, the opening degree of the fuel cell fuel control valve 4c is controlled according to the calculated fuel amount to be supplied (S35).

Next, a target engine speed is set according to the calculated air amount to be supplied (S36). Since the engine 3 also functions as a blower, the air supply amount is adjusted according to the engine speed.
Next, the engine 3 is controlled so that the engine 3 reaches the target rotational speed (S37). In controlling the engine, the opening degree of the fuel injection valves 4d and 4e is adjusted.
In this way, appropriate electric power is generated by the SOFC 2 while the vehicle is traveling.

Next, a fuel cell system according to a second embodiment as a reference example will be described with reference to FIG.
FIG. 4 is a schematic diagram showing the basic configuration of the fuel cell system according to the second embodiment. In FIG. 4, the same reference numerals are assigned to the components corresponding to the components shown in FIG.

  The fuel cell system according to the second embodiment is a power source for driving an electric vehicle, and basically, a reformer 1 that generates a reformed gas containing hydrogen by adding water vapor to a fuel gas containing a hydrocarbon compound. And SOFC 2 to which the reformed gas is supplied from the reformer 1.

  In FIG. 4, the path of the fuel gas supplied to the reformer 1 is indicated by a solid line 10a. The amount of fuel gas supplied is adjusted by the opening of the fuel gas control valve 8a. Each gas path shown in FIG. 4 is formed by a pipe (not shown).

  The reformer 1 is provided with an offgas heat exchanger 4 that heats the reformer 1 by exchanging heat between the offgas discharged from the SOFC 2 and the reformer 1.

The reformed gas generated in the reformer 1 is supplied to the fuel electrode (anode) 2a of the SOFC 2. Air (Air) is supplied to the air electrode (cathode) 2b of the SOFC2.
In FIG. 4, the path of the reformed gas supplied from the reformer 1 to the SOFC 2 is indicated by a solid line 10b, and the path of the air supplied to the SOFC 2 is indicated by a broken line 11a.

  In the SOFC 2, hydrogen in the reformed gas supplied to the fuel electrode 2 a and oxygen in the air supplied to the air electrode 2 b react to generate water, and a power generation reaction that generates electricity is performed. . Electricity generated by the power generation reaction is sent to a secondary battery (not shown) connected to the ceramic electrode of each of the fuel electrode 2a and the air electrode 2b and a drive motor (not shown) of the electric vehicle.

The off gas discharged from the fuel electrode 2 a of the SOFC 2 is guided to the off gas heat exchanger 4 provided in the reformer 1. Further, the offgas is cooled by the offgas heat exchanger 4.
FIG. 4 shows a path of off gas guided from the fuel electrode 2a of the SOFC 2 to the off gas heat exchanger 4 by a solid line 10c, and a path of off gas guided from the air electrode 2b of the SOFC 2 to the off gas heat exchanger 4 by a broken line 11b.

  In 2nd Embodiment, the collection means 7a which collects water from the offgas cooled with the offgas heat exchanger 4 is provided. The collecting means 7a is composed of a drain 71 for discharging water condensed on the inner wall of the pipe of the off-gas passage 10d from the pipe, and a water tank 72 for storing water discharged from the drain 71.

  The water collected by the collecting means 7a is used as steam in the reformer 1. Specifically, the water stored in the common water tank 72 is supplied to the reformer 1 through the pipe 74 and is heated by the heat of the reformer 1 to become steam. In this way, the reforming water used as the steam for the reforming reaction in the reformer 1 can be self-supplied.

  In each embodiment mentioned above, although the example which constituted the present invention on specific conditions was explained, the present invention can perform various change and combination, and is not limited to this. For example, in the first embodiment described above, the example in which the off gas is supplied to the internal combustion engine after passing through the heat exchange mechanism of the reformer 1 has been described. However, in the present invention, the off gas is not passed through the reformer 1. Alternatively, it may be supplied directly to the internal combustion engine.

  In the above-described embodiment, the fuel cell system of the present invention is described as an example of a fuel cell system for driving an electric vehicle. However, the use of the fuel cell system of the present invention is not limited to an electric vehicle. The present invention can also be applied to an installation facility such as a power plant.

  In the above-described embodiment, the example in which the gas discharged from both the fuel electrode and the air electrode of the SOFC is supplied to the internal combustion engine as an off-gas has been described. However, in the present invention, the gas discharged from the fuel electrode of the SOFC Only off-gas may be supplied to the internal combustion engine. That is, in the present invention, the SOFC off-gas includes at least exhaust gas from the fuel electrode and may include exhaust gas from the air electrode.

  In the above-described embodiment, an example in which both the first exhaust gas heat exchanger that exchanges heat with the reformer and the second exhaust gas heat exchanger that exchanges heat with the SOFC has been described. One of the first and second exhaust gas heat exchangers may be omitted.

  Moreover, although the above-mentioned embodiment demonstrated the example which uses LPG as a use fuel, in this invention, it is not limited to this, For example, you may use other fuels, such as ethanol.

  The fuel cell system of the present invention can be used, for example, as a power source mounted on an electric vehicle.

1 Reformer 2 SOFC
2a Fuel electrode (anode)
2b Air electrode (cathode)
3 Engine 4 Off-gas heat exchanger 5 First exhaust gas heat exchanger 6 Second exhaust gas heat exchanger 7a, 7b Collection means 8a Fuel gas control valve 8b Air control valve 8c Fuel control valve 8d First exhaust path control valve 8e Second exhaust path control valve 9 Control unit 31 Intake port 32 Exhaust port 33 Cylinder 34 Piston rod 35 Motor / generator 71, 73 Drain 72 Common water tank

Claims (4)

A reformer for generating a reformed gas containing hydrogen by adding water vapor to a fuel gas containing a hydrocarbon compound;
A solid oxide fuel cell to which a reformed gas is supplied from the reformer;
An internal combustion engine that sucks off-gas discharged from the solid oxide fuel cell as part of the fuel;
One of the reformer and the solid oxide fuel cell is subjected to heat exchange between the exhaust gas discharged from the internal combustion engine and one or both of the reformer and the solid oxide fuel cell. Or an exhaust gas heat exchanger that heats both ,
First collecting means for collecting water from the exhaust gas cooled by the exhaust gas heat exchanger, and using the water collected by the first collecting means as water vapor in the reformer ,
The exhaust gas heat exchanger is provided in both the reformer and the solid oxide fuel cell,
A first passage for guiding exhaust gas heat-exchanged with the reformer;
A second passage for guiding the exhaust gas heat-exchanged with the solid oxide fuel cell;
With
The first collecting means is provided on the downstream side of a joining portion where the first passage and the second passage join.
A fuel cell system. An off-gas heat exchanger that heats the reformer by performing heat exchange between the off-gas discharged from the solid oxide fuel cell and the reformer;
A second collecting means for collecting water from the off-gas cooled by the off-gas heat exchanger, and using the water collected by the second collecting means as water vapor in the reformer,
The fuel cell system according to claim 1 . The first and second collecting means have a common water tank for collecting collected water.
The fuel cell system according to claim 2 . Supply the collected water to the reformer and heat it with the heat of the reformer to make steam.
The fuel cell system according to any one of claims 1 to 3 , wherein:

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