JP2003109634A - Fuel cell system and operation method of fuel cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stably perform reduction processing of a fuel cell while confirming the condition of an electrode and the like, and to automatically control hydrogen density in accordance with the situation in the fuel cell. SOLUTION: This fuel cell system comprises a fuel supply pipe 19/20 having a gas adjusting part 15 for adjusting a flow rate of a fuel gas 1 and supplying the fuel gas 1, a fuel cell pipe 12/3 having a double pipe structure of an inner pipe 12 having an opened end and an outer pipe 3 having a closed end, and provided with a cell of the fuel cell on an outer face of the outer pipe 3, and a control part 13 measuring the voltage of a cell 11 of the fuel cell mounted on a terminal end of a flow passage of the fuel gas 1 supplied from the fuel supply pipe 19/20, passed through the inner pipe 12, turned at the closed end, and flowing between the inner pipe 12 and the outer pipe 3, and controlling the gas adjusting part 15 on the basis of a result of the measurement of the voltage.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a fuel cell system and a method for operating a fuel cell.

[0002]

2. Description of the Related Art FIG. 10 shows an example of a schematic configuration of a conventional fuel cell power generation system. However, in FIG. 10, a gas supply source, a part related to preheating and heat exchange of gas, a part related to collection of generated electric power, and the like are omitted.

Referring to FIG. 10, a fuel cell includes a header 110 which is a gas supply section and a cell tube 1 which is a power generation section.
And 11. The header 110 includes a partition plate 110a,
It has a bottom plate 110b, a supply chamber 110c, and a discharge chamber 110d. The cell tube also has a guide tube 112.

The inside of the header 110 is vertically divided by a partition plate 110a, and the upper part is a supply chamber 110c and the lower part is a discharge chamber 110d. Header 11
An upper end portion (one end portion) of the cell tube 111 is connected to and supported by the bottom plate 110b of No. 0 and the discharge chamber 110d so that gas can flow in and out. The lower end (the other end) of the cell tube 111 is closed. Cell tube 1
A guide tube 112 is coaxially inserted into the inside of the shaft 11. The guide tube 112 has one end (upper end)
The partition plate 110a is connected and supported so that gas can flow in and out of the supply chamber 110c. There are a plurality of such cell tubes 111 and guide tubes 112, which are connected to and supported by the header 110. Here, the cell tube 111 is a cylindrical cell tube that constitutes a combustion battery in which fuel cells are formed on the outer peripheral surface of a porous substrate tube.

A fuel cell (not shown) formed on the cell tube 111 has a base tube formed on the outer peripheral surface of the base tube of the cell tube 111 with the fuel electrode-electrolyte-air electrode (laminated) as one unit. A plurality of them are continuously formed with a constant width in the longitudinal direction. Then, the electrolyte and the air electrode of the adjacent fuel cell and the fuel electrode are joined by the membrane of the interconnector. A protective film for protecting the interconnector may be formed on the interconnector.

In the steady operation of the fuel cell having such a structure, the fuel gas 1 such as hydrogen or methane is supplied into the supply chamber 110c, and oxygen or air is supplied along the outer peripheral surface of the cell tube 111. Such an oxidizing gas 2 is supplied. Then, the fuel gas 1 flows into each guide tube 112 at a uniform flow rate and reaches the tip of the guide tube 112. After that, the fuel gas 1 becomes the cell tube 11
It folds back from the closed lower end (other end) in 1 and flows from the lower end (other end) of the cell tube 111 toward the upper end (one end). Then, the side surface (wall surface) of the base tube diffuses outward and reaches the fuel electrode. on the other hand,
The oxidant gas 2 enters from the outside and enters the cell tube 111.
Reach the air electrode on the outer periphery of the. The fuel gas 1 and the oxidant gas 2 are the fuel cell 2 of the cell tube 111.
To generate electric power by reacting electrochemically.

However, in the case of the first operation after manufacturing, when the apparatus is started up, first, the oxidized electrode (fuel electrode) and the
It is necessary to reduce the lead film having the function of the lead wire. That is, since the cell tube 111 is manufactured by firing all the electrodes and the like in an oxidizing atmosphere, all the electrodes and the like are oxidized. For example, when nickel is used as the fuel electrode, it is nickel oxide. When used as a fuel cell, it is necessary to reduce them so that they can perform their original functions (reduce nickel oxide to nickel).

In this case, in the reduction operation, the hydrogen flow rate is increased while monitoring the overall voltage of the fuel cell.
This will be described with reference to FIG. On the vertical axis, the left side is the open circuit voltage per fuel cell, and the right side is the hydrogen concentration at the fuel outlet of the fuel cell (outlet hydrogen concentration). The horizontal axis is
The temperature in the fuel cell system. The reduction process proceeds while gradually raising the temperature inside the furnace. Further, at a low temperature stage, the hydrogen concentration in the supplied fuel gas is lowered for safety.

The reduction of the fuel electrode progresses as the temperature rises. Along with that, hydrogen is consumed, and open circuit voltage (OCV)
And the outlet hydrogen concentration decreases. When the hydrogen is exhausted, the current collecting part of the metal is oxidized and it becomes impossible to generate electricity. In order to avoid this, immediately before the outlet hydrogen concentration becomes 0%, the hydrogen concentration in the supplied fuel gas is increased so that the outlet hydrogen concentration becomes about 5%. The reason for raising only 5% is for safety (considering the lower limit of explosion of hydrogen) and for eliminating waste of fuel. The temperature in the fuel cell system is 700 to 1000 ° C.
And the open circuit voltage per fuel cell becomes approximately 1.2V.

The adjustment of the hydrogen concentration is carried out by adjusting the hydrogen concentration of the entire fuel cell while monitoring the voltage of the entire fuel cell. Therefore, the response of the outlet hydrogen concentration to the change of the supplied hydrogen concentration. However, it is difficult to predict the above, and it is difficult to automate because there are difficulties such as the fact that it is not possible to consider the variation in hydrogen concentration in the fuel gas supplied to each fuel cell.

Further, the reduction of the fuel electrode and the lead film was confirmed by passing a weak current and by the voltage drop thereof. Doing so under conditions of low hydrogen concentration can lead to overcurrent and damage to the cell. Therefore, it was difficult to automate the adjustment of the weak current.

[0012]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a fuel cell system and a fuel cell operating method capable of stably reducing the electrodes and the like of the fuel cell.

Another object of the present invention is to provide a fuel cell system and a fuel cell operating method capable of stably confirming the state of reduction of the electrodes and the like of the fuel cell.

Still another object is to provide a fuel cell system and a fuel cell operating method capable of confirming the distribution status of the fuel gas in the fuel cell.

Another object of the present invention is to provide a fuel cell system and a fuel cell operating method capable of automatically controlling the hydrogen concentration according to the state of the fuel cell.

[0016]

Means for Solving the Problem In the section of the means for solving the problem, the reference numerals and symbols are given to show the correspondence between the claims and the embodiments of the invention. It should not be used to interpret the claims.

In order to solve the above problems, the fuel cell system of the present invention has a fuel gas (FIG. 1, 1) having a gas adjusting section (FIG. 1, 15) for adjusting the flow rate of the fuel gas (FIG. 1, 1). Fuel supply pipe for supplying 1) (Fig. 1, 19 and 20)
And a double tube structure of an inner pipe (FIGS. 1 and 12) having an open end and an outer pipe (FIGS. 1 and 3) having a closed end.
3) a fuel cell tube having fuel cells formed on the outer surface (FIG. 1, 12/3) and a fuel supply tube (FIG. 1, 19.2)
0) Fuel gas (Fig. 1, 1) is the inner pipe (Fig. 1, 12)
The inner tube (Fig. 1, 12) folded back through its closed end
And the outer tube (Figs. 1, 3), and the fuel gas (Fig. 1,
1) The fuel cell (FIG. 1,
11) is provided, and the control unit (FIGS. 1 and 13) that controls the gas adjusting unit (FIGS. 1 and 15) based on the measurement result of the voltage is provided.

Further, the fuel cell system of the present invention has a gas adjusting section (FIG. 7, 1) for adjusting the flow rate of the fuel gas (FIG. 7, 1).
15), a fuel supply pipe (FIGS. 7, 19 and 20) for supplying a fuel gas (FIGS. 7 and 1), and a fuel cell pipe in which fuel cells are formed on the surface of a base pipe (FIGS. 7 and 3) And fuel gas from the fuel supply pipe (Fig. 7, 19 and 20) (Fig. 7,
1) flows through the fuel cell tube (FIGS. 7 and 3), and the voltage of the fuel cell (FIGS. 7 and 11) provided at the final end of the flow path of the fuel gas (FIGS. 7 and 1) is measured. And a control unit (FIGS. 7 and 13) for controlling the gas adjustment unit (FIGS. 7 and 15) based on the voltage measurement result.

Further, in the fuel cell system of the present invention, the gas adjusting portion (FIG. 3, 1) for adjusting the flow rate of the fuel gas (FIG. 3, 1).
15), a fuel supply pipe (FIGS. 3, 19 and 20) for supplying a fuel gas (FIGS. 3, 1), an inner pipe having an open end (FIGS. 3, 12) and an outer pipe having a closed end (FIGS. 3, 3) having a double-tube structure, in which a fuel cell and a lead film for taking out the generated power are formed on the outer surface of the outer tube (FIGS. 3, 3) (FIGS. 3, 12). 3) and the fuel gas from the fuel supply pipe (FIGS. 3, 19 and 20) (FIGS. 3, 1) are passed through the inner pipe (FIGS. 3, 12) and folded back at their closed ends, so that the inner pipe (FIG. , 12) and the outer tube (FIGS. 3, 3), and measuring the resistance of the lead film (FIGS. 3, 11) provided at the final end of the flow path of the fuel gas (FIGS. 3, 1). And a control unit (FIG. 3, 13) for controlling the gas control unit (FIG. 3, 15) based on the measurement result of the resistance.

Further, in the fuel cell system of the present invention, the gas adjusting section (FIG. 8, 1) for adjusting the flow rate of the fuel gas (FIG. 8, 1).
15), a fuel supply pipe (FIGS. 8, 1 and 20) for supplying a fuel gas (FIGS. 8 and 1), a fuel cell and a lead film for extracting generated electric power on the surface of the base pipe. And the fuel supply pipe (Fig. 8, 3)
The fuel gas (Figs. 8 and 1) from (19, 20) flows through the fuel cell tube (Figs. 8 and 3), and the lead film (Fig. The control unit (FIGS. 8 and 13) controls the gas adjusting unit (FIGS. 8 and 15) based on the resistance measurement result.

Further, the fuel cell system of the present invention includes a gas sensor (Fig. 1/3/7/8, 14) for measuring the hydrogen concentration at the time of discharging the fuel gas (Fig. 1/3/7/8, 1). And a fuel discharge pipe (FIG. 1/3/7/8, 23.25) for discharging the fuel gas (FIG. 1/3/7/8, 1), and a control unit (FIG. 1/3 / 7/8, 13) controls the gas regulator (Fig. 1/3/7/8, 15) based on the voltage measurement result and the hydrogen concentration measurement result.

Further, in the fuel cell system of the present invention, the fuel cell tube (Fig. 1/3, 12.3, Fig. 7/8, 3) is
Fuel gas than other fuel cell tubes (Fig. 1/3/7 /
The supply of 8 and 1) is small.

In order to solve the above-mentioned problems, the fuel cell operating method of the present invention comprises a step of supplying a fuel gas (Fig. 1/7, 1) to the fuel cell formed on the surface of the base tube,
Based on the step of measuring the voltage of the last fuel cell (Fig. 1/7, 11) in the flow path of the fuel gas (Fig. 1/7, 1) among the fuel cells, and the measurement result of the voltage , Controlling the supply amount of the fuel gas (Fig. 1/7, 1).

Further, the fuel cell operating method of the present invention comprises the step of supplying the fuel gas (FIG. 3/8, 1) to the lead film for taking out the electric power generated by the fuel cell formed on the surface of the base tube. Of the lead film, fuel gas (Fig. 3/8,
The last lead film in the channel of 1) (Fig. 3/8, 10)
And measuring the resistance of the lead gas, and controlling the supply amount of the fuel gas (Fig. 3/8, 1) based on the measurement result of the lead resistance.

Furthermore, the fuel cell operating method of the present invention further comprises the step of measuring the hydrogen concentration at the time of discharging the fuel gas (Fig. 1/3/7/8, 1). 3 /
The step of controlling the supply amount of 7/8, 1) is performed based on the result of the voltage or resistance measurement and the result of the hydrogen concentration measurement.

[0026]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a fuel cell system and a method for operating a fuel cell according to the present invention will be described below with reference to the accompanying drawings. In this embodiment, a fuel cell system having a cylindrical fuel cell cell tube and a method of operating the same will be described by way of example, but the invention can be applied to other fuel cells. Note that the same or corresponding portions in the respective embodiments will be described with the same reference numerals.

(Embodiment 1) The configuration of a first embodiment of a fuel cell system and a method of operating a fuel cell according to the present invention will be described with reference to the drawings. FIG. 1 is a diagram (cross-sectional view) showing a configuration of a first embodiment of a fuel cell system according to the present invention. The fuel cell system includes a cell tube 3 as an outer tube of a fuel cell tube, an oxidant. A supply chamber 4, a header 5 having a tube plate A6, a tube plate B7, a supply chamber 8 and an exhaust chamber 9, a lead film 10, a fuel cell 11, a guide tube 12 as an inner tube of the fuel cell tube, and a controller 13. , Gas sensor 14, gas adjusting valve 15 as a gas adjusting unit, adjusting valve control line 16, measuring line A17, measuring line B18, fuel gas supplying pipe 19 and fuel gas introducing pipe 20 as a fuel supplying pipe, oxidant gas supplying pipe 21, oxidant gas discharge pipe 2
2. A fuel gas outlet pipe 23 as a fuel discharge pipe, a fuel gas discharge pipe 25, and a gas sensor line 24. In addition,
The configuration of FIG. 1 is installed in a container that takes into consideration heat insulation and gas leak safety (not shown). In addition, in the present drawing, a configuration relating to current collection is omitted.

In the present invention, while automatically monitoring the voltage of the portion (FIG. 1, fuel cell 11) where the fuel (hydrogen) supply amount is the smallest (FIG. 1, control unit 13), the fuel flow rate ( Concentration) is controlled (FIG. 1, control unit 13) to satisfactorily reduce the electrodes and the lead film, which is different from the conventional technique. Since the focus is on the voltage in the part where the fuel (hydrogen) supply amount is the smallest, if the necessary fuel is supplied in that part, no problem will occur in other parts. Therefore, the stability and reliability of the fuel cell system as a whole can be secured. Further, since the voltage is acquired and the control is automatically performed based on the voltage, it is a stable method that does not depend on the ability of each individual, and is an efficient method that does not require human intervention. Therefore, the reliability in power generation is increased, the probability of failure is reduced, and the cost can be reduced.

Each configuration will be described in detail below. The fuel cell system will be described with reference to FIG.

The cell tube 3 as an outer tube of the fuel cell cell tube is a cylindrical tube constituting a combustion cell in which a fuel cell is formed on the outer peripheral surface of a porous ceramic substrate tube. The cell tube 3 has a discharge chamber 9 at one end.
It is opened and joined to and supported by a tube sheet B7 (described later) (described later). The other end side is closed and extends to the oxidant supply chamber 4. A guide tube 12 is provided inside the cell tube 3. The material of the cell tube 3 is zirconia. In FIG. 1, only one cell is shown as a representative, but a plurality of cells exist, and the number is determined according to the scale of the fuel cell system. A fuel electrode, an electrolyte, and an air electrode are sequentially stacked on the outer peripheral surface at regular intervals in the longitudinal direction of the base tube to form a fuel cell (not shown). Each cell is joined by an interconnector (not shown). The fuel gas 1 is supplied to the fuel cell of the cell tube 3 from the lower end (the other end) of the cell tube 3 via a guide tube 12 (described later). Then, it diffuses in the holes in the thickness direction of the base tube, reaches the fuel electrode, and contributes to power generation together with the oxidant gas 2 flowing outside the cell tube 3.

The fuel battery cell 11 is a fuel battery cell in which a fuel electrode, an electrolyte and an air electrode are laminated in this order. In the present embodiment, in particular, in the cell tube 3 that supplies the least amount of fuel (hydrogen), the fuel cell that is located at the most end on the upper end (one end) side of the cell tube 3 that supplies the least amount of fuel (hydrogen). Refers to a cell. Fuel electrode (The anode is a catalyst for producing water or carbon dioxide by combining oxygen ions transported in the electrolyte with hydrogen or carbon monoxide in the fuel gas 1 when the electrolyte is an oxygen ion conductor. In this embodiment, nickel / zirconia is used, and the electrolyte is used for the fuel cell to generate electricity.
It is an oxygen ion conductor that transports oxygen ions. In this example, it is stabilized zirconia. Air electrode (cathode)
When the electrolyte is an oxygen ion conductor, is a catalyst for ionizing oxygen in the oxidant gas 2 and supplying it to the electrolyte, and is also an electrode. In this example, it is lantern manganites.

A plurality of fuel cells are present in a plurality of cell tubes 3 present in the fuel cell system, are continuously formed along the circumference of the cell tube 3 in one round, and the cell tubes 3 are provided. Are formed with a constant width in the longitudinal direction. Adjacent fuel cells are connected in series by an interconnector (not shown, ceramic or metal film). The fuel battery cell 11 is a fuel battery cell that supplies the least amount of fuel (hydrogen) among them.

The lead film 10 comprises a plurality of fuel cells 11
It is a film that plays a role of a lead wire for drawing out one pole of the DC power generated in 1. to a current collector (electrode terminal (not shown) connected to the upper end (one end) of the cell tube 3). A dense protective film (an insulating layer of a metal oxide film) is laminated so that the film is not oxidized during the operation of the fuel cell system. The cell tube 3 is connected to the air electrode (or fuel electrode) of the fuel cell 11 that is located at the uppermost end (one end) of the cell tube 3. The lead film 10 extends from the air electrode along the outer peripheral portion of the cell tube 3 to the upper end portion (one end portion) thereof. The width in the circumferential direction may be the entire surface of the power generation substrate tube or a specific width so that the resistance is sufficiently low depending on the magnitude of the generated power and the thickness of the lead film 22.

Guide tube 12 as inner tube of fuel cell cell tube
Is connected at its upper end (one end) to the tube plate A6 so that the fuel gas 1 having entered the supply chamber 8 is supplied to the cell tube 3, and is opened and joined. The lower end (the other end) is open in the vicinity of the lower end (the other end is closed) inside the cell tube 3 without contacting it. The fuel gas 1 that has entered the supply chamber reaches the lower end portion of the guide tube 12 (the other end portion = the lower end (the other end) of the cell tube 3), exits there, and is inside the cell tube 3 and inside the guide tube 12 The outside of the cell tube is moved toward the upper end (one end) of the cell tube 3. During the movement, the gas diffuses toward the outside of the side surface of the cell tube 3 and reaches the fuel cell provided outside the tube. And, it contributes to the power generation performed there.

The fuel cell tube is a guide tube 1 as an inner tube.
2 and the cell tube 3 as an outer tube form a double tube structure, and the fuel cell and the lead film are formed on the outer surface thereof.

The control unit 13 controls the regulating valve control line 16 based on the voltage output from the fuel cell 11 through the measurement line A17 (described later) and the measurement line B18 (described later).
It is a control device that controls a supply amount of the fuel gas 1 by adjusting a gas adjusting valve 15 (described later) via (described later). that time,
Data on the relationship between the preset output voltage of the fuel cell unit 11 and the flow rate of the supplied fuel gas 1 is stored in a storage unit (not shown) in the control unit 13. Further, based on the hydrogen concentration of the spent fuel gas 1 from the gas sensor 14 (described later) via the gas sensor line 24, the gas regulating valve 15 (described later) is regulated via the regulating valve control line 16 (discussed below), and the fuel is adjusted. It is also possible to control the supply amount of the gas 1.
At that time, the hydrogen concentration on the supply side is adjusted so as to reach the preset hydrogen concentration. Further, it is possible to determine the supply amount of the fuel gas 1 to be supplied by referring to both of them at the same time. At that time, data of the relationship between the preset output voltage of the fuel cell 11, the hydrogen concentration of the spent fuel gas 1 and the flow rate of the supplied fuel gas 1 is stored in a storage unit (not shown) in the control unit 13. ) Have.

The control unit 13 may be integrated with or separate from a control device for controlling not only the fuel gas 1 but also the entire fuel cell system.

The measuring line A17 is a voltage terminal for measuring the voltage of the fuel cell 11 and its lead wire. One electrode of the fuel cell 11 (for example, fuel electrode)
And the measurement terminal of the control unit 13 are connected. Similarly,
The measurement line B18 is a voltage terminal for measuring the voltage of the fuel cell 11 and its lead wire. The other electrode (for example, an air electrode) of the fuel cell 11 is connected to the measurement terminal of the control unit 13.

The gas sensor 14 is a sensor for hydrogen gas which is installed between the fuel gas outlet pipe 23 and the end of the fuel gas outlet pipe 23 on the side opposite to the header 5 and the fuel gas discharge pipe 25. It is composed of a sensor and piping for circulating gas. The concentration of hydrogen gas contained in the spent fuel gas 1 passing through the inside is measured. One end of the gas sensor line 24 is the gas sensor 1
4, the other end is connected to the control unit 13. It is a line that sends the output of the data measured by the gas sensor 14 to the control unit 13.

The gas adjusting valve 15 as a gas adjusting section is connected in the middle of the fuel gas supply pipe 19. It is an adjusting valve that adjusts the supply amount of the fuel gas 1 to the header 5 (cell tube 3) based on the signal output from the control unit 13. The regulating valve control line 16 has one end connected to the controller 13 and the other end connected to the gas regulating valve 15. It is a line that sends a signal related to the gas supply amount set by the control unit 13 to the gas regulating valve 15.

The oxidant supply chamber 4 is adjacent to the lower side (one side) of the header 5 (described later), and is isolated so that the fuel gas of the header 5 and the oxidant gas of the oxidant supply chamber 4 are not mixed. There is. And, including most of the cell tube 3,
This is a chamber for supplying an oxidant gas to the cell tube 3.

Next, the supply chamber 8, the discharge chamber 9 and the tube sheet A6
And the header 5 having the tube sheet B7 will be described. The supply chamber 8 is a gas distribution chamber located above the upper end (one end) of the guide tube 12 and having a hollow rectangular parallelepiped shape or a cylindrical shape. In this embodiment, it is a rectangular parallelepiped. The fuel gas 1 is supplied from a fuel gas introduction pipe 20 (described later). There may be a case in which a mechanism (not shown) such as a straightening plate that regulates the flow of gas is attached inside. A fuel gas introduction pipe 20 is connected to the top plate on the upper side and is opened and connected. Further, the bottom surface is a tube plate A6 (described later), and the guide tube 12 is attached thereto. The guide tube 12 is connected to the tube plate A6 so that the fuel gas 1 entering the supply chamber 8 is supplied to the cell tube 3, and is opened and joined. The supply chamber 8 uniformly supplies the fuel gas 1 to each of the plurality of cell tubes 3 that are present. At the same time, it is a metal chamber that also supports the cell tubes 3.

The discharge chamber 9 is a gas distribution chamber located above the upper end (one end) of the cell tube 3 and having a hollow rectangular parallelepiped shape or a cylindrical shape. In this embodiment, it is a rectangular parallelepiped. The used fuel gas 1 is discharged from the fuel gas outlet pipe 23 (described later). There may be a case in which a mechanism (not shown) such as a straightening plate that regulates the flow of gas is attached inside. The upper top plate is a tube plate A6 (described later), and the fuel gas outlet tube 23
Are connected and open to connect. Further, the bottom surface is a tube plate B7 (described later), and the cell tube 3 is attached thereto. The cell tube 3 is connected to the tube sheet B7 so that the spent fuel gas 1 discharged from the cell tube 3 can be collected, and is opened and joined. At the same time, it is a metal chamber that also supports the cell.

The tube plate A6 is a plate on the bottom surface of the supply chamber 8,
The holes for connecting the guide tubes 12 are opened (as many as the guide tubes 12). The guide pipe 12 and the upper end portion (one end portion) of the guide pipe 12 are connected so that the fuel gas 1 can enter and leave the supply chamber 8, and are connected to the supply chamber 8 side so as to be open. And it is a metal plate that firmly supports the guide tube 12. Further, the fuel gas outlet pipe 23 and the fuel gas 1 are connected so that the fuel gas 1 can flow in and out of the discharge chamber 9 and are open and joined to the discharge chamber 9 side.

The tube plate B7 is the bottom plate of the discharge chamber 9,
The hole for connecting the cell tube 3 is (cell tube 3
It's open). Further, the cell tube 3 and the upper end portion (one end portion) of the cell tube 3 are connected to each other so that the fuel gas 1 can flow in and out, and the fuel gas 1 is opened and joined to the discharge chamber 9 side. And it is a metal plate which supports the cell tube 3.

Next, the fuel gas supply pipe 19 and the fuel gas introduction pipe 20 as fuel supply pipes will be described. The fuel gas supply pipe 19 is one of the pipes for supplying the fuel gas 1 to the header 5. A gas adjusting valve 15 for adjusting the flow rate of the fuel gas 1 is provided on the way. Then, one end is connected to the fuel gas introduction pipe 20, and the fuel gas 1 is connected to the fuel gas introduction pipe 20.
It is flowing to.

The fuel gas introduction pipe 20 is one of the pipes for supplying the fuel gas 1 to the header 5. One end thereof is connected to the fuel gas supply pipe 19, and the other end is connected to the top plate of the supply chamber 8 of the header 5 and is open and joined to the supply chamber 8 side.
Further, it has a double pipe structure coaxial with the fuel gas outlet pipe 23. However, the fuel gas introduction pipe 20 is an outer pipe, and the fuel gas outlet pipe 23 is an inner pipe. The fuel gas 1 coming from the fuel gas supply pipe 19 is supplied to the supply chamber 8.

Next, the fuel gas outlet pipe 23 and the fuel gas exhaust pipe 25 as the fuel exhaust pipe will be described. The fuel gas outlet pipe 23 is one of the pipes for discharging the used fuel gas 1 from the header. One end thereof is connected to a tube plate A6 which is a top plate of the discharge chamber 9 of the header 5 and is opened and joined to the discharge chamber 9 side. The other end extends in a direction away from the header 5, and the middle part thereof is the fuel gas introduction pipe 2
It has a double tube structure coaxial with 0. However, the fuel gas introduction pipe 20 is an outer pipe, and the fuel gas outlet pipe 23 is an inner pipe.
The gas sensor 14 is provided at the other end of the double pipe structure.
have.

The fuel gas discharge pipe 25 is the fuel gas outlet pipe 2
3 is a pipe for discharging the used fuel gas 1 that has passed through the gas sensor 3 and the gas sensor 14.

The oxidant gas supply pipe 21 is a pipe for supplying the oxidant gas 2 to the oxidant supply chamber 4. The supplied oxidant gas 2 reaches the air electrode on the outer peripheral portion of the cell tube 3,
Contribute to its power generation. The oxidant gas discharge pipe 22 is a pipe for discharging the used oxidant gas 4 used in the oxidant supply chamber 4.

The fuel gas 1 is a mixed gas of the fuel gas 1 such as hydrogen, methane, propane and city gas and water vapor. However, when starting up the fuel cell system, it is a mixed gas of nitrogen-balanced hydrogen gas and water vapor. Also,
The oxidant gas is oxygen, air, or a mixed gas containing them.

The operation of the first embodiment of the fuel cell system and the method of operating the fuel cell according to the present invention will be described with reference to the drawings. Referring to FIG. 1, in the fuel cell system having such a configuration, the fuel cell is started up. First, the oxidant gas 2 is supplied to the oxidant supply chamber 4 through the oxidant gas supply pipe 21. At the time of supply, by preheating the oxidant gas 2 at a certain rate of temperature increase, the power generation unit (the cell tube 3 in the oxidant supply chamber 4 and its peripheral portion) is also heated at a rate of temperature increase. .

On the other hand, as for the fuel gas 1, when the temperature of the power generation section is low and power is not being generated, first, the fuel gas 1 having a low hydrogen concentration (about several%) is supplied. The fuel gas 1 is supplied with the fuel gas while the flow rate of the fuel gas is adjusted by a gas adjusting valve 15 that adjusts the flow rate of the fuel gas.
It is supplied to the header 5 via 9 and the fuel gas introduction pipe 20. Then, the fuel gas 1 is guided to the guide tube 12, which is an inner tube having open ends of the fuel cell tubes, so that all the fuel electrodes and the lead films in all the cell tubes 3 in the fuel cell system are reduced. Distributed and supplied. And
The cell tube 3 is folded back through the guide tube 12 at the lower end portion (the other end portion) which is the closed end of the cell tube 3, and between the guide tube 12 and the cell tube 3, that is, between the inner tube and the outer tube. Flows toward the upper end (one end) of the. At this time, the fuel gas 1 diffuses in the outer peripheral direction at the wall surface (side surface) of the cell tube 3. And the hydrogen in the fuel gas 1
It reaches the fuel electrode and the lead film of the fuel cell (including the fuel cell 11) and reduces them. At that time, control is performed so that hydrogen in the fuel gas 1 supplied to the fuel electrode and the lead film is not consumed and hydrogen is exhausted. Therefore, the following control is performed.

With reference to FIG. 1, the control unit 13 measures the voltage of the fuel cell 11 provided at the final end of the flow path of the fuel gas 1. That is, the voltage of the fuel cell 11 having the smallest supply amount (closest to the discharge chamber 8) of the cell tube 3 having the smallest supply amount of the fuel gas 1 in the fuel cell system is measured and monitored. Then, the voltage change is monitored, and the gas regulating valve 15 is controlled based on the voltage measurement result so that the value does not become abnormal.
The supply amount is adjusted. If so, the hydrogen concentration in the supplied fuel gas 1 will not be insufficient. Since the other fuel cells have a higher hydrogen concentration in the fuel gas 1 than the fuel cells 11, no problem occurs if the fuel cells 11 have no problem.

Furthermore, as described above, the following control is performed on the premise that a sufficient amount of the fuel gas 1 is also supplied to the fuel cell unit 11. The control unit 13
The gas sensor 14 measures the hydrogen concentration at the time of discharging the fuel gas 1 at the outlet of the fuel cell system (hereinafter, “outlet hydrogen concentration”). The value here is 5 from the viewpoint of safety.
The gas regulating valve 15 is controlled so as to be kept to be not more than%, and to maintain a constant value other than zero. Keeping below 5%
The reason for maintaining safety at the lower explosive limit and the efficiency of reducing hydrogen utilization, and keeping it at a non-zero constant value (= excess hydrogen) is in the cell tube 3
This is because a sufficient amount of hydrogen can be stably supplied for the reduction treatment in step 1.

Further description will be given with reference to FIG. The vertical axis is
The left side is the open circuit voltage (OCV) of the fuel cell 11,
The right side shows the hydrogen concentration at the fuel outlet of the fuel cell (outlet hydrogen concentration). The horizontal axis is the temperature in the fuel cell system. The reduction process proceeds while gradually raising the temperature inside the furnace. For safety, the hydrogen concentration in the supplied fuel gas is lowered until the temperature is sufficiently high and the power generation is ready after the reduction is completed. The outlet gas concentration of the spent fuel gas 1 discharged by reducing the fuel electrode and the lead film of the cell tube 3 is 5%, which is kept at a low constant value. However, since the hydrogen gas concentration is still 5% in the used state, it can be said that the fuel gas 1 supplied had a necessary amount.

Further, in FIG. 2, the open circuit voltage (OCV) of the fuel cell unit 11 gradually rises with temperature, and the reduction is satisfactorily progressing. That is, it can be seen that there is a sufficient amount of hydrogen gas and the reduction proceeds at a temperature-controlled rate. As the actual control, first, the control unit 13 sets the outlet hydrogen concentration to a preset value (here, 5%),
The fuel gas is allowed to flow while adjusting the gas adjusting valve 15 to maintain the outlet hydrogen concentration of 5%. On the other hand, the control unit 13 has data (in a storage unit (not shown)) on the relationship between the temperature and the open circuit voltage, and the open circuit voltage predicted from the temperature of the power generation unit and the data,
The actual open circuit voltage (fuel cell 11) is compared. Then, the control unit 13 controls the open circuit voltage (V
OC) is a certain level (for example, ± 10% of the predicted value)
If it is within the range, it is determined that there is no abnormality and control continues as it is. However, when the actual open circuit voltage falls below a certain level, the gas regulating valve 15 is adjusted to increase the fuel (hydrogen) so that the open circuit voltage becomes an appropriate value.

Subsequently, when the measured open circuit voltage (fuel cell 11) is equal to or higher than a preset value (for example, 1.2 V) when the temperature has risen sufficiently, the control unit 13 causes sufficient reduction. Judge that it is progressing, apply a weak initial current,
It is examined whether the fuel cell and the lead film of each cell tube 3 have sufficient performance. Referring to FIG. 4, the horizontal axis represents the current flowing through the fuel cell of the cell tube 3. The vertical axis represents the voltage for each cell tube (or each group of cell tubes). If the reduction of the fuel cell is successful, the current-voltage characteristic as shown by the curve a is exhibited. The control unit 13 compares the relationship between the weak current and the voltage, the reference data of the relationship between the current and the voltage (in a storage unit (not shown)) that is stored in advance, and the actual relationship between the weak current and the voltage, and maintains a certain value. If it is within the level of (for example, ± 2% of the standard data), there is no abnormality. However, when the actual reduction of the relation between the weak current and the voltage is below a certain level, it is determined that the reduction is insufficient, the current is cut off, and the reduction process is performed again. For example, in the current-voltage characteristics shown by the curve b, the internal resistance is very large and the reduction is insufficient.

In the state shown by the curve b, the fuel gas 1 is further supplied than the fuel cell 11 in which the supply amount of the fuel gas 1 is the smallest.
There is a possibility that the reduction in the lead film 10 in which the supply of oxygen is small is insufficient and the resistance of the lead film 10 is high. Therefore, in order to prevent this, the resistance of the lead film 10 may be monitored instead of the fuel cell 11 as shown in FIG. Figure 3
Is similar to that of FIG. 1, except that the measurement line A1
7 and the measurement line B18 are connected to the lead film 10, which is different from FIG. 1 and 3 are combined, a measurement line is connected to the fuel cell 11 that supplies the least amount of the fuel gas 1 and the lead film 10 that supplies the least amount of the fuel gas 1 and is used for control by the controller 13. If so, it is possible to perform the reduction treatment more reliably.

If a weak initial current is passed and the current-voltage characteristic as shown by the curve a in FIG. 4 is obtained, the fuel cell is in a good state and normal power generation is started.

The fuel gas 1 is supplied into the supply chamber 8 through the fuel gas supply pipe 19 and the gas regulating valve 15 and the fuel gas introduction pipe 20.
Supplied from The fuel gas 1 flows into each guide tube 12 at a uniform flow rate. The fuel gas 1 travels through the guide tube 12, and when it comes out from the lower end (the other end) of the guide tube 12, the lower end (the other end) of the cell tube 3 moves outside the guide tube 12 inside the cell tube 3. It flows toward the upper end (one end) of the cell tube 3. At this time, the fuel gas 1 diffuses on the wall surface (side surface) of the cell tube 3 and reaches the anode side of the fuel cell 11. On the other hand, the oxidant gas 2 such as oxygen or air is supplied along the outer peripheral surface of the cell tube 3 in the oxidant supply chamber 4. They reach the cathode side of the fuel cell. Then, the electrochemical reaction between the fuel gas 1 and the oxidant gas 2 in the fuel battery cell causes electric power generation and generation of electric power.

The used fuel gas 1 is the cell tube 3
From the upper end portion (one end portion) to the discharge chamber 9. And
It is discharged from the fuel gas discharge pipe 25 via the fuel gas outlet pipe 23 and the gas sensor 14. On the other hand, the used oxidant gas 2 is discharged from the oxidant supply chamber 4 through the oxidant gas discharge pipe 22.

By the above process, it becomes possible to automatically carry out the initial reduction treatment at the lead film 10 in the cell tube 3 and the fuel electrode of the fuel cell unit, thereby reducing the human burden and cost. Becomes

(Embodiment 2) The configuration of the second embodiment of the fuel cell system and the method of operating the fuel cell according to the present invention will be described with reference to the drawings. FIG. 1 is a diagram (cross-sectional view) showing a configuration of a second embodiment of a fuel cell system according to the present invention. The fuel cell system includes a cell tube 3 as an outer tube of a fuel cell tube, an oxidant. A supply chamber 4, a header 5 having a tube plate A6, a tube plate B7, a supply chamber 8 and an exhaust chamber 9, a lead film 10, a fuel cell 11, a guide tube 12 as an inner tube of the fuel cell tube, and a controller 13. , Gas sensor 14, gas adjusting valve 15 as a gas adjusting unit, adjusting valve control line 16, measuring line A17, measuring line B18, fuel gas supplying pipe 19 and fuel gas introducing pipe 20 as a fuel supplying pipe, oxidant gas supplying pipe 21, oxidant gas discharge pipe 2
2. A fuel gas outlet pipe 23 as a fuel discharge pipe, a fuel gas discharge pipe 25, and a gas sensor line 24. In addition,
The configuration of FIG. 1 is installed in a container that takes into consideration heat insulation and gas leak safety (not shown). In addition, in the present drawing, a configuration relating to current collection is omitted.

In the present invention, when the fuel cell system is operating in a steady state, the voltage of the portion (fuel cell 11 in FIG. 1) where the fuel (hydrogen) supply amount is the smallest is automatically monitored (FIG. 1, control unit 13). ) By automatically controlling the fuel flow rate (concentration) appropriately (FIG. 1, control unit 13) based on the voltage change of the fuel cell or the lead film when the fuel gas 1 in the fuel cell system is abnormal. Unlike the prior art, the situation is handled safely without causing a sudden shutdown due to an interlock or the like. Since the focus is on the voltage at the part where the fuel (hydrogen) supply amount is the smallest, if the necessary fuel is supplied at that part and appropriate measures are taken, no problems will occur for other parts. Therefore, the stability and reliability of the fuel cell system as a whole can be secured. Further, since the voltage is acquired and the control is automatically performed based on the voltage, it is a stable method that does not depend on the ability of each individual, and is an efficient method that does not require human intervention. Therefore, the reliability in power generation is increased, the probability of failure is reduced, and the cost can be reduced.

Each configuration will be described in detail below. The fuel cell system will be described with reference to FIG.

The control unit 13 controls the gas adjusting valve 15 via the adjusting valve control line 16 based on the voltage output from the fuel cell 11 via the measuring line A17 (described later) and the measurement line B18 (described later). It is a control device that adjusts and controls the supply amount of the fuel gas 1. For example, when the output voltage of the fuel cell 11 becomes equal to or lower than the preset reference voltage Vs, the supply amount of the fuel gas 1 is automatically and gradually increased,
The output voltage is maintained at the reference voltage Vs or higher. Data of the reference voltage Vs is stored in a storage unit (not shown) in the control unit 13. Further, based on the hydrogen concentration of the spent fuel gas 1 from the gas sensor 14 (described later) via the gas sensor line 24, the gas regulating valve 15 (described later) is regulated via the regulating valve control line 16 (discussed below), and the fuel is adjusted. It is also possible to control the supply amount of the gas 1. At that time, the hydrogen concentration on the supply side is adjusted so that the preset reference hydrogen concentration C _H2 is _reached . Data of the reference hydrogen concentration C _H2 is stored in a storage unit (not shown) in the control unit 13. Further, it is possible to determine the supply amount of the fuel gas 1 to be supplied by referring to both of them at the same time. At that time, the storage unit (not shown) in the control unit 13 has data on the relationship between the reference voltage Vs, the reference hydrogen concentration C _H2, and the flow rate of the supplied fuel gas 1.

The control unit 13 may be integrated with or separate from a control device for controlling not only the fuel gas 1 but also the entire fuel cell system.

The functions of the control unit 13 other than the above and the functions of other configurations are the same as those in the first embodiment, and therefore the description thereof is omitted.

The fuel gas 1 is a mixed gas of the fuel gas 1 such as hydrogen, methane, propane and city gas, and water vapor. However, when starting up the fuel cell system, it is a mixed gas of nitrogen-balanced hydrogen gas and water vapor. Also,
The oxidant gas is oxygen, air, or a mixed gas containing them.

The operation of the second embodiment of the fuel cell system and fuel cell operating method according to the present invention will be described with reference to the drawings. Referring to FIG. 1, in the fuel cell system having such a configuration, during steady operation, fuel gas 1 such as hydrogen, methane, and steam is supplied to fuel gas supply pipe 19 in supply chamber 8. And
The gas adjustment valve 15 controlled by the controller 13 adjusts the flow rate and reaches the fuel gas introduction pipe 20. After that, the fuel gas 1 is supplied to the supply chamber 8, and from there, the fuel gas 1 flows into the guide pipe 12, which is an inner pipe having open ends of the fuel cell pipes, at a uniform flow rate.

Fuel gas supply pipe 19 and fuel gas introduction pipe 2
Fuel gas 1 from 0 travels through the guide tube 12 and
When it comes out from the lower end (the other end) of the cell tube 3, it hits the lower end (the other end) which is the closed end of the cell tube 3. Then, the fuel gas 1 is folded back from there and flows inside the cell tube 3 outside the guide tube 12, that is, between the inner tube and the outer tube, toward the upper end portion (one end portion) of the cell tube 3. At this time, the fuel gas 1 diffuses on the wall surface (side surface) of the cell tube 3 and reaches the anode side of the fuel cell (including the fuel cell 11). On the other hand, the oxidant gas 2 such as oxygen or air is supplied along the outer peripheral surface of the cell tube 3 in the oxidant supply chamber 4. They reach the cathode side of the fuel cells (including the fuel cell 11). Then, the fuel cell (fuel cell 11
(Including), electric power is generated and electric power is generated.

At this time, the control unit 13 measures the voltage of the fuel cell 11 provided at the final end of the flow path of the fuel gas 1. That is, the voltage of the fuel cell 11 having the smallest supply amount (closest to the discharge chamber 8) of the cell tube 3 having the smallest supply amount of the fuel gas 1 in the fuel cell system is measured and monitored. Then, based on the measurement result of the voltage, the control unit 13 controls the gas regulating valve 15 to regulate the flow rate of the fuel gas 1.

In the fuel cell 11 as described above,
It is also possible to perform the following control on the assumption that a sufficient amount of fuel gas 1 is supplied and normal operation is performed. The control unit 13 uses the gas sensor 14 to measure the hydrogen concentration at the outlet of the fuel cell system when the fuel gas 1 is discharged (hereinafter, “outlet hydrogen concentration”).
The value here is kept below a preset value. Keeping the value below the set value is for keeping the fuel utilization rate above the preset value.

Referring to FIG. 5, the vertical axis represents the cell tube 3
(Or a plurality of groups of cell tube 3) is the output voltage of the horizontal axis is the operation elapsed time (around time t _A). When the output voltage falls below a preset reference voltage Vs at a certain point in time (immediately before t _A ) during operation, after a lapse of a certain time, at a time t _A , the control unit 13 turns on the gas control valve 15. Adjust to gradually increase the fuel gas 1 flow rate. Then, as a result, the supply of the fuel gas 1 to each fuel cell increases, and the control unit 13 controls the gas control valve 15 so that the output voltage of the fuel cell 11 can be restored to the reference voltage Vs or higher. Control.

At this time, it is important not to increase the flow rate of the fuel gas 1 significantly but to increase it slightly to the extent that the reference voltage Vs is satisfied (see the voltage change at the time t _A of the curve c). As a result, a large pressure difference is not generated between the fuel side and the air side.

A conventional example is shown in FIG. Referring to FIG. 6, the vertical axis represents the cell tube 3 (or a plurality of cell tubes 3
The output voltage of the (group consisting of) and the horizontal axis are the elapsed operation time (near time t _A ). Conventionally, when the output voltage is lower than a preset reference voltage Vs, an interlock is generated, a load is cut off, and a fuel cell is protected. However, due to the rapid gas flow rate change due to the current stoppage, a large pressure difference was generated between the fuel side and the air side, possibly damaging the cell. However, in the present embodiment, as described above, the current is not stopped (the load is not cut off) and the change in the flow rate of the fuel gas 1 is suppressed as much as possible, so that there is no possibility of damaging the cell and the safety is ensured. It is a reliable method.

The used fuel gas 1 is the cell tube 3
From the upper end portion (one end portion) to the discharge chamber 9. And
It is discharged from the fuel gas discharge pipe 25 via the fuel gas outlet pipe 23 and the gas sensor 14. On the other hand, the used oxidant gas 2 is discharged from the oxidant supply chamber 4 through the oxidant gas discharge pipe 22.

By the above process, by monitoring the voltage value of the fuel cell in the cell tube 3, it becomes possible to automatically cope with the output abnormality of the fuel cell, thereby reducing the human burden and the cost. .

(Embodiment 3) The configuration of a third embodiment of the fuel cell system and the method of operating the fuel cell according to the present invention will be described with reference to the drawings. FIG. 7 is a diagram (cross-sectional view) showing the configuration of the third embodiment of the fuel cell system according to the present invention. The fuel cell system includes a cell tube 3 as a fuel cell cell tube and an oxidant supply chamber 4. , Tube sheet C2
6, tube sheet D27, supply chamber 8, discharge chamber 9, lead film 10,
Fuel cell 11, control unit 13, gas sensor 14, gas adjusting valve 15 as a gas adjusting unit, adjusting valve control line 1
6, measurement line A17, measurement line B18, fuel gas supply pipe 19 as a fuel supply pipe and fuel gas introduction pipe 20,
Oxidant gas supply pipe 21, oxidant gas exhaust pipe 22, fuel gas outlet pipe 23 as fuel exhaust pipe, and fuel gas exhaust pipe 2
5, gas sensor line 24, support A28, support B2
It consists of 9. In addition, the configuration of FIG. 7 is installed in a container in consideration of heat insulation and gas leak safety not shown. In addition, in the present drawing, a configuration relating to current collection is omitted.

In this embodiment, the cell tube 3 is supported at both ends (both vertically and horizontally). That is, it is supported at two points by the support A28 and the support B29. Gas sealing is performed at two points of the tube plate C26 on the supply chamber 8 side and the tube plate D27 on the discharge chamber 9 side. That is,
While supporting the cell tube at two points, a member dedicated to sealing is introduced in addition to the heat insulating material that is supported and entered. Fuel gas 1
Is a one-way (one-through) gas flow that enters the cell tube 3 from the supply chamber 8 and is discharged to the discharge chamber 9. Therefore, the guide tube is unnecessary. The above points are different from the first embodiment.

Each configuration will be described in detail below. The fuel cell system will be described with reference to FIG. 7.

Cell tube 3 as fuel cell cell tube
Is a cylindrical tube forming a combustion battery, in which fuel cells are formed on the outer peripheral surface of a porous ceramic base tube. The cell tube 3 has one end side in a supply chamber 8 (described later),
The other end is fitted and supported in the discharge chamber 9 (described later). The one end side is open to the supply chamber 8 (described later) and the other end side is opened to the discharge chamber 9 (described later) so that gas can flow in and out. Inside, the guide tube in Example 1 to Example 2,
Does not include. The material is, for example, zirconia.
In FIG. 7, only three cells are shown as a representative, but there are a plurality of cells and the number is determined according to the scale of the fuel cell system. A fuel cell, in which a fuel electrode, an electrolyte, and an air electrode are sequentially stacked on the outer peripheral surface at regular intervals in the longitudinal direction of the base tube. Are formed (not shown). Each cell is joined by an interconnector (not shown).
The fuel gas 1 is supplied to the fuel cell of the cell tube 3 from one end of the cell tube 3 via a supply chamber 8 (described later). Then, it diffuses in the holes in the thickness direction of the base tube, reaches the fuel electrode, and contributes to power generation together with the oxidant gas 2 flowing outside the cell tube 3.

The fuel cell 11 is a fuel cell in which a fuel electrode, an electrolyte and an air electrode are laminated in this order. In the present embodiment, in particular, in the cell tube 3 that supplies the least amount of fuel (hydrogen), it is located at the end of the other end (on the side of the discharge chamber 9) of the cell tube 3 that supplies the least amount of fuel (hydrogen). Refers to fuel cells. That is, it is the most difficult place for the fuel gas 1 to reach. When the electrolyte is an oxygen ion conductor, the fuel electrode (anode) combines oxygen ions transported in the electrolyte with hydrogen or carbon monoxide in the fuel gas 1 to generate water or carbon dioxide. It is both a catalyst and an electrode. In this embodiment, it is nickel / zirconia. The electrolyte is for the fuel cell to generate electricity,
It is an oxygen ion conductor that transports oxygen ions. In this example, it is stabilized zirconia. Air electrode (cathode)
When the electrolyte is an oxygen ion conductor, is a catalyst for ionizing oxygen in the oxidant gas 2 and supplying it to the electrolyte, and is also an electrode. In this example, it is lantern manganites.

A plurality of fuel cells are present in the cell tubes 3 which are present in the fuel cell system, and are continuously formed along the circumference of the cell tube 3 in one round. Are formed with a constant width in the longitudinal direction. Adjacent fuel cells are connected in series by an interconnector (not shown, metal film). The fuel battery cell 11 is a fuel battery cell that supplies the least amount of fuel (hydrogen) among them.

The lead film 10 is composed of a plurality of fuel cells 11
Membrane serving as a lead wire for drawing out one pole of the DC power generated in step 1 to a current collector (electrode terminal (not shown) connected to the other end of the cell tube 3 (on the discharge chamber 9 side)) Is. A dense protective film (an insulating layer of a metal oxide film) is laminated so that the film is not oxidized during the operation of the fuel cell system. The cell tube 3 is connected to the air electrode (or fuel electrode) of the fuel cell 11 that is located at the uppermost end (one end) of the cell tube 3. Then, the lead film 10 extends from the air electrode to the outer peripheral portion of the cell tube 3 to the other end portion. The width in the circumferential direction is set so that the resistance is sufficiently low depending on the magnitude of generated power and the thickness of the lead film 10.

The oxidant supply chamber 4 is a tube plate C2 (of the supply chamber 8).
6) and (the tube plate D27 of) the discharge chamber 9 and isolated from them, including the cell tube 3. This is a chamber for supplying an oxidant gas to the cell tube 3. Then, the support A is provided in the vicinity of each of the inner tube sheet C26 and the tube sheet D27.
28 and the support B29 are each fixed. The room is made of metal such as stainless steel or heat-resistant alloy.

The supply chamber 8 is a gas distribution chamber located at one end of the cell tube 3 and having a hollow rectangular parallelepiped shape or a cylindrical shape. In this embodiment, it is a rectangular parallelepiped. It has a gas supply port 8-1 for receiving the supply of the fuel gas 1. There may be a case in which a mechanism (not shown) such as a straightening plate that regulates the flow of gas is attached inside. One surface is a tube plate C26 (described later)
And the cell tube 3 is attached. The cell tube 3 is connected and joined to the tube plate C26 so that the fuel gas 1 having entered the supply chamber 8 is supplied to the cell tube 3. It is a chamber made of metal such as stainless steel or a heat-resistant alloy that uniformly supplies the fuel gas 1 to each of the cell tubes 3 existing in plural.

The discharge chamber 9 is located at the other end of the cell tube 3 and is a gas distribution chamber having a hollow rectangular parallelepiped shape or a cylindrical shape. In this embodiment, it is a rectangular parallelepiped. It has a gas outlet 9-1 for discharging the used fuel gas 1. There may be a case in which a mechanism (not shown) such as a straightening plate that regulates the flow of gas is attached inside. One side is tube sheet D
27 (described later), to which the cell tube 3 is attached. The cell tube 3 is connected and joined to the tube plate D27 so that the spent fuel gas 1 discharged from the cell tube 3 can be collected. The room is made of metal such as stainless steel or heat-resistant alloy.

The tube plate C26 is a plate on one surface of the supply chamber 8, and has holes (as many as the cell tubes 3) for connecting the cell tubes 3 open. The cell tube 3 and one end of the cell tube 3 are connected so that gas can flow in and out, and are connected by being opened. The joint is a tube sheet C2
6 does not leak gas from the gap between the cell tube 3 and the cell tube 3, so that it is possible to absorb displacement such as stress, vibration, and shock, such as a thin metal plate such as stainless steel or heat resistant alloy. Use a flexible material. If necessary, in order to ensure gas tightness, a filler is used to completely suppress the leak.

The tube plate D27 is a plate on one surface of the discharge chamber 9, and has holes (as many as the number of cell tubes 3) for connecting the cell tubes 3 open. The cell tube 3 and the other end of the cell tube 3 are connected so that gas can flow in and out, and are opened and joined. The joint is a tube sheet D2
7 does not leak gas from the gap between the cell tube 3 and the cell tube 3, so that it is possible to absorb positional displacement due to stress, vibration, and shock, such as a thin metal plate such as stainless steel or heat-resistant alloy. Use a flexible material. If necessary, in order to ensure gas tightness, a filler is used to completely suppress the leak.

Next, the fuel gas supply pipe 19 and the fuel gas introduction pipe 20 as fuel supply pipes will be described. The fuel gas supply pipe 19 is one of the pipes for supplying the fuel gas 1 to the supply chamber 8. Then, one end is connected to a gas adjusting valve 15 for adjusting the flow rate of the fuel gas 1, and the fuel gas 1 is flown into the fuel gas introducing pipe 20.

The fuel gas introduction pipe 20 is one of the pipes for supplying the fuel gas 1 to the supply chamber 8. One end thereof is connected to a gas adjusting valve 15 that adjusts the flow rate of the fuel gas 1, and the other end is connected to a gas supply port 8-1 of the supply chamber 8 and is open and joined to the supply chamber 8 side. . The fuel gas 1 coming from the fuel gas supply pipe 19 is supplied to the supply chamber 8.

Next, the fuel gas outlet pipe 23 and the fuel gas exhaust pipe 25 as the fuel exhaust pipe will be described. The fuel gas outlet pipe 23 is one of the pipes for discharging the used fuel gas 1 from the discharge chamber 9. One end thereof is connected to the gas exhaust port 9-1 of the exhaust chamber 9 and is open and joined to the exhaust chamber 9 side. The other end is connected to the gas sensor 14.

The fuel gas discharge pipe 25 has one end connected to the gas sensor 14 (described later). Used fuel gas 1 that has passed through the fuel gas outlet pipe 23 and the gas sensor 14.
It is a pipe for discharging.

The support A28 and the support B29 are the tube sheet C.
26 and the tube sheet D27, and is fixed in the oxidant supply chamber 4 outside the supply chamber 8 and the discharge chamber 9. The cell tube 3 is supported at the portions on both ends of the cell tube 3 where there are no fuel cells. Further, the heat of the cell tube 3 on the power generation side is shut off, and the tube sheet C26 and the tube sheet D27, or the gas seal portion which is the joint portion between the cell tube 3 and the tube sheet C26 or the tube sheet D27,
Thermal protection. Examples of the material include porous silica, porous alumina, silica, alumina, and a porous body containing magnesia as a main component.

The fuel gas 1 as the first gas is a mixed gas of the fuel gas 1 such as hydrogen, methane, propane and city gas and water vapor. However, when starting up the fuel cell system, it is a mixed gas of nitrogen-balanced hydrogen gas and water vapor. The oxidant gas as the second gas is oxygen, air, or a mixed gas containing them.

The other structure in FIG. 7 is the same as that of the embodiment 1 having the same number, and the description thereof will be omitted.

The operation of the third embodiment of the fuel cell system and fuel cell operating method according to the present invention will be described with reference to the drawings. Referring to FIG. 7, in the fuel cell system having such a configuration, the fuel cell is started up. First, the oxidant gas 2 is supplied to the oxidant supply chamber 4 through the oxidant gas supply pipe 21. At the time of supply, by preheating the oxidant gas 2 at a certain rate of temperature increase, the power generation unit (the cell tube 3 in the oxidant supply chamber 4 and its peripheral portion) is also heated at a rate of temperature increase. .

On the other hand, as for the fuel gas 1, when the temperature of the power generation section is low and power is not being generated, first, the fuel gas 1 having a low hydrogen concentration (about several%) is supplied. The fuel gas 1 is supplied with the fuel gas while the flow rate of the fuel gas is adjusted by a gas adjusting valve 15 that adjusts the flow rate of the fuel gas.
It is supplied to the supply chamber 8 via 9 and the fuel gas introduction pipe 20. Then, the fuel gas 1 flows from one end of the cell tube 3 to each cell tube 3 which is each fuel cell cell tube so that all the fuel electrodes and the lead films in all the cell tubes 3 in the fuel cell system are reduced. Distributed and supplied. Then, it flows toward the other end of the cell tube 3.
At this time, the fuel gas 1 diffuses in the outer peripheral direction at the wall surface (side surface) of the cell tube 3. Then, the hydrogen in the fuel gas 1 reaches the fuel electrode and the lead film of the fuel cell (including the fuel cell 11) and reduces them.
At that time, control is performed so that hydrogen in the fuel gas 1 supplied to the fuel electrode and the lead film is not consumed and hydrogen is exhausted. Therefore, the following control is performed.

Referring to FIG. 7, control unit 13 measures the voltage of fuel cell 11 provided at the final end of the flow path of fuel gas 1. That is, the voltage of the fuel cell 11 having the smallest supply amount (closest to the discharge chamber 8) of the cell tube 3 having the smallest supply amount of the fuel gas 1 in the fuel cell system is measured and monitored. Then, the voltage change is monitored, and the gas regulating valve 15 is controlled based on the voltage measurement result so that the value does not become abnormal.
Is adjusting the supply amount of. If so, the hydrogen concentration in the supplied fuel gas 1 will not be insufficient. Since the other fuel cells have a higher hydrogen concentration in the fuel gas 1 than the fuel cells 11, no problem occurs if the fuel cells 11 have no problem.

Further, as described above, the following control is performed on the premise that a sufficient amount of the fuel gas 1 is supplied also to the fuel cell 11. The control unit 13
The gas sensor 14 measures the hydrogen concentration at the time of discharging the fuel gas 1 at the outlet of the fuel cell system (hereinafter, “outlet hydrogen concentration”). The value here is 5 from the viewpoint of safety.
The gas regulating valve 15 is controlled so as to be kept to be not more than%, and to maintain a constant value other than zero. Keeping below 5%
The reason for maintaining safety at the lower explosive limit and the efficiency of reducing hydrogen utilization, and keeping it at a non-zero constant value (= excess hydrogen) is in the cell tube 3
This is because a sufficient amount of hydrogen can be stably supplied for the reduction treatment in step 1.

Further description will be given with reference to FIG. The vertical axis is
The left side is the open circuit voltage (OCV) of the fuel cell 11,
The right side shows the hydrogen concentration at the fuel outlet of the fuel cell (outlet hydrogen concentration). The horizontal axis is the temperature in the fuel cell system. The reduction process proceeds while gradually raising the temperature inside the furnace. For safety, the hydrogen concentration in the supplied fuel gas is lowered until the temperature is sufficiently high and the power generation is ready after the reduction is completed. The outlet gas concentration of the spent fuel gas 1 discharged by reducing the fuel electrode and the lead film of the cell tube 3 is 5%, which is kept at a low constant value. However, since the hydrogen gas concentration is still 5% in the used state, it can be said that the fuel gas 1 supplied had a necessary amount.

Further, in FIG. 2, the open circuit voltage (OCV) of the fuel cell unit 11 gradually rises with temperature, and the reduction is satisfactorily progressing. That is, it can be seen that there is a sufficient amount of hydrogen gas and the reduction proceeds at a temperature-controlled rate. As the actual control, first, the control unit 13 sets the outlet hydrogen concentration to a preset value (here, 5%),
The fuel gas is allowed to flow while adjusting the gas adjusting valve 15 to maintain the outlet hydrogen concentration of 5%. On the other hand, the control unit 13 has data (in a storage unit (not shown)) on the relationship between the temperature and the open circuit voltage, and the open circuit voltage predicted from the temperature of the power generation unit and the data,
The actual open circuit voltage (fuel cell 11) is compared. Then, the control unit 13 controls the open circuit voltage (V
OC) is a certain level (for example, ± 10% of the predicted value)
If it is within the range, it is determined that there is no abnormality and control continues as it is. However, when the actual open circuit voltage falls below a certain level, the gas regulating valve 15 is adjusted to increase the fuel (hydrogen) so that the open circuit voltage becomes an appropriate value.

Subsequently, when the measured open-circuit voltage (fuel cell 11) is equal to or higher than a preset value (for example, 1.2 V) when the temperature has risen sufficiently, the control unit 13 causes the reduction to be sufficient. Judge that it is progressing, apply a weak initial current,
It is examined whether the fuel cell and the lead film of each cell tube 3 have sufficient performance. Referring to FIG. 4, the horizontal axis represents the current flowing through the fuel cell of the cell tube 3. The vertical axis represents the voltage for each cell tube (or each group of cell tubes). If the reduction of the fuel cell is successful, the current-voltage characteristic as shown by the curve a is exhibited. The control unit 13 compares the relationship between the weak current and the voltage, the reference data of the relationship between the current and the voltage (in a storage unit (not shown)) that is stored in advance, and the actual relationship between the weak current and the voltage, and maintains a certain value. If it is within the level of (for example, ± 2% of the standard data), there is no abnormality. However, when the actual reduction of the relation between the weak current and the voltage is below a certain level, it is determined that the reduction is insufficient, the current is cut off, and the reduction process is performed again. For example, in the current-voltage characteristics shown by the curve b, the internal resistance is very large and the reduction is insufficient.

In the state shown by the curve b, the fuel gas 1 is supplied more than the fuel cell 11 in which the supply amount of the fuel gas 1 is the smallest.
There is a possibility of insufficient reduction in the lead film 10 in which the supply of oxygen is small. Therefore, in order to prevent this, the resistance of the lead film 10 may be monitored instead of the fuel cell 11 as shown in FIG. The configuration of FIG. 8 is similar to that of FIG.
However, the point that the measurement line A17 and the measurement line B18 are connected to the lead film 10 is different from FIG. 7 and 8
When the measurement line is connected to the fuel cell 11 that supplies the least amount of the fuel gas 1 and the lead film 10 that supplies the least amount of the fuel gas 1 together and is used for control by the control unit 13, Can be reliably performed.

If a weak initial current is passed and the current-voltage characteristic as shown by the curve a in FIG. 4 is obtained, the fuel cell is in a good state and normal power generation is started.

The fuel gas 1 is supplied into the supply chamber 8 through the fuel gas supply pipe 19 and the gas control valve 15 and the fuel gas introduction pipe 20 is supplied.
Supplied from The fuel gas 1 flows into each cell tube 3 from one end thereof at a uniform flow rate,
It flows toward the other end of the cell tube 3. At this time, the fuel gas 1 diffuses on the wall surface (side surface) of the cell tube 3 and reaches the anode side of the fuel cell 11. On the other hand, the oxidant gas 2 such as oxygen or air is supplied along the outer peripheral surface of the cell tube 3 in the oxidant supply chamber 4. They reach the cathode side of the fuel cell. And fuel gas 1
The electrochemical reaction between the oxidant gas 2 and the oxidant gas 2 causes electric power to be generated and electric power to be generated.

The used fuel gas 1 is the cell tube 3
From the other end to the discharge chamber 9. Then, the fuel gas discharge pipe 2 is provided via the fuel gas outlet pipe 23 and the gas sensor 14.
Emitted from 5. On the other hand, the used oxidant gas 2 is
It is discharged from the oxidant supply chamber 4 through the oxidant gas discharge pipe 22.

By the process described above, it becomes possible to automatically carry out the initial reduction treatment at the lead film 10 in the cell tube 3 and the fuel electrode of the fuel cell unit, thereby reducing human burden and cost reduction. Becomes

(Embodiment 4) The construction of a fourth embodiment of the fuel cell system and the method of operating the fuel cell according to the present invention will be described with reference to the drawings. FIG. 7 is a diagram (cross-sectional view) showing the configuration of the fourth embodiment of the fuel cell system according to the present invention. The fuel cell system includes a cell tube 3 as a fuel cell cell tube and an oxidant supply chamber 4. , Tube sheet C2
6, tube sheet D27, supply chamber 8, discharge chamber 9, lead film 10,
Fuel cell 11, control unit 13, gas sensor 14, gas adjusting valve 15 as a gas adjusting unit, adjusting valve control line 1
6, measurement line A17, measurement line B18, fuel gas supply pipe 19 as a fuel supply pipe and fuel gas introduction pipe 20,
Oxidant gas supply pipe 21, oxidant gas exhaust pipe 22, fuel gas outlet pipe 23 as fuel exhaust pipe, and fuel gas exhaust pipe 2
5, gas sensor line 24, support A28, support B2
It consists of 9. In addition, the configuration of FIG. 7 is installed in a container in consideration of heat insulation and gas leak safety not shown. In addition, in the present drawing, a configuration relating to current collection is omitted.

In this embodiment, the cell tube 3 is supported at both ends (both vertically and horizontally). That is, it is supported at two points by the support A28 and the support B29. Gas sealing is performed at two points of the tube plate C26 on the supply chamber 8 side and the tube plate D27 on the discharge chamber 9 side. That is,
While supporting the cell tube at two points, a member dedicated to sealing is introduced in addition to the heat insulating material that is supported and entered. Fuel gas 1
Is a one-way (one-through) gas flow that enters the cell tube 3 from the supply chamber 8 and is discharged to the discharge chamber 9. Therefore, the guide tube is unnecessary. The above points are different from the second embodiment.

Each configuration will be described in detail below. The fuel cell system will be described with reference to FIG. 7.

The control unit 13 controls the gas adjusting valve 15 via the adjusting valve control line 16 based on the voltage output from the fuel cell 11 via the measuring line A17 (described later) and the measuring line B18 (described later). It is a control device that adjusts and controls the supply amount of the fuel gas 1. For example, when the output voltage of the fuel cell 11 becomes equal to or lower than the preset reference voltage Vs, the supply amount of the fuel gas 1 is automatically and gradually increased,
The output voltage is maintained at the reference voltage Vs or higher. Data of the reference voltage Vs is stored in a storage unit (not shown) in the control unit 13. Further, based on the hydrogen concentration of the spent fuel gas 1 from the gas sensor 14 (described later) via the gas sensor line 24, the gas regulating valve 15 (described later) is regulated via the regulating valve control line 16 (discussed below), and the fuel is adjusted. It is also possible to control the supply amount of the gas 1. At that time, the hydrogen concentration on the supply side is adjusted so that the preset reference hydrogen concentration C _H2 is _reached . Data of the reference hydrogen concentration C _H2 is stored in a storage unit (not shown) in the control unit 13. Further, it is possible to determine the supply amount of the fuel gas 1 to be supplied by referring to both of them at the same time. At that time, the storage unit (not shown) in the control unit 13 has data on the relationship between the reference voltage Vs, the reference hydrogen concentration C _H2 and the flow rate of the supplied fuel gas 1.

The control unit 13 may be integrated with or separate from a control device for controlling not only the fuel gas 1 but also the entire fuel cell system.

The functions of the control unit 13 other than the above and the functions of other configurations are the same as those in the third embodiment, and therefore the description thereof is omitted.

The fuel gas 1 is a mixed gas of the fuel gas 1 such as hydrogen, methane, propane and city gas and water vapor. However, when starting up the fuel cell system, it is a mixed gas of nitrogen-balanced hydrogen gas and water vapor. Also,
The oxidant gas is oxygen, air, or a mixed gas containing them.

The operation of the fourth embodiment of the fuel cell system and fuel cell operating method according to the present invention will now be described with reference to the drawings. Referring to FIG. 7, in the fuel cell system having such a configuration, during steady operation, fuel gas 1 such as hydrogen, methane, and steam is supplied to fuel gas supply pipe 19 in supply chamber 8. And
The gas adjustment valve 15 controlled by the controller 13 adjusts the flow rate and reaches the fuel gas introduction pipe 20. After that, the fuel gas 1 is supplied to the supply chamber 8, and from there, the fuel gas 1 flows into the cell tubes 3, which are the fuel cell cells, at a uniform flow rate.

Fuel gas supply pipe 19 and fuel gas introduction pipe 2
The fuel gas 1 from 0 is supplied from the supply chamber 8 to one end of the cell tube 3 and flows toward the other end. At this time,
The fuel gas 1 diffuses on the wall surface (side surface) portion of the cell tube 3 and reaches the anode side of the fuel cell (including the fuel cell 11). On the other hand, the oxidant gas 2 such as oxygen or air is supplied along the outer peripheral surface of the cell tube 3 in the oxidant supply chamber 4. They are fuel cells (fuel cell 11
(Including) is reached. Electric power is generated by an electrochemical reaction between the fuel gas 1 and the oxidant gas 2 in the fuel cell (including the fuel cell 11),
Electricity is generated.

At this time, the control unit 13 measures the voltage of the fuel cell 11 provided at the final end of the flow path of the fuel gas 1. That is, the voltage of the fuel cell 11 having the smallest supply amount (closest to the discharge chamber 8) of the cell tube 3 having the smallest supply amount of the fuel gas 1 in the fuel cell system is measured and monitored. Then, based on the measurement result of the voltage, the control unit 13 controls the gas regulating valve 15 to regulate the flow rate of the fuel gas 1.

In the fuel cell 11 as described above,
It is also possible to perform the following control on the assumption that a sufficient amount of fuel gas 1 is supplied and normal operation is performed. The control unit 13 uses the gas sensor 14 to measure the hydrogen concentration at the outlet of the fuel cell system when the fuel gas 1 is discharged (hereinafter, “outlet hydrogen concentration”).
The value here is kept below a preset value. Keeping the value below the set value is for keeping the fuel utilization rate above the preset value.

With reference to FIG. 5, the vertical axis represents the cell tube 3
(Or a plurality of groups of cell tube 3) is the output voltage of the horizontal axis is the operation elapsed time (around time t _A). When the output voltage falls below a preset reference voltage Vs at a certain point in time (immediately before t _A ) during operation, after a lapse of a certain time, at a time t _A , the control unit 13 turns on the gas control valve 15. Adjust to gradually increase the fuel gas 1 flow rate. Then, as a result, the supply of the fuel gas 1 to each fuel cell increases, and the control unit 13 controls the gas control valve 15 so that the output voltage of the fuel cell 11 can be restored to the reference voltage Vs or higher. To do.

At this time, it is important not to increase the flow rate of the fuel gas 1 to a large extent, but to slightly increase it to the extent that the reference voltage Vs is satisfied (see the voltage change at the time t _A of the curve c). As a result, a large pressure difference is not generated between the fuel side and the air side.

FIG. 6 shows a conventional example. Referring to FIG. 6, the vertical axis represents the cell tube 3 (or a plurality of cell tubes 3
The output voltage of the (group consisting of) and the horizontal axis are the elapsed operation time (near time t _A ). Conventionally, when the output voltage is lower than a preset reference voltage Vs, an interlock is generated, a load is cut off, and a fuel cell is protected. However, due to the rapid gas flow rate change due to the current stoppage, a large pressure difference was generated between the fuel side and the air side, possibly damaging the cell. However, in the present embodiment, as described above, the current is not stopped (the load is not cut off) and the change in the flow rate of the fuel gas 1 is suppressed as much as possible, so that there is no possibility of damaging the cell and the safety is ensured. It is a reliable method.

The used fuel gas 1 is the cell tube 3
From the upper end portion (one end portion) to the discharge chamber 9. And
It is discharged from the fuel gas discharge pipe 25 via the fuel gas outlet pipe 23 and the gas sensor 14. On the other hand, the used oxidant gas 2 is discharged from the oxidant supply chamber 4 through the oxidant gas discharge pipe 22.

By the above process, by monitoring the voltage value of the fuel cell in the cell tube 3, it becomes possible to automatically cope with the output abnormality of the fuel cell, thereby reducing the human burden and the cost. Become.

According to the present invention, the initial reduction process at the lead film in the cell tube 3 and the fuel electrode of the fuel cell can be automatically performed by monitoring the voltage of the fuel cell 11. Therefore, there is no need for a human burden as in the past, and labor can be reduced.

Since only the fuel cells with the least amount of fuel (hydrogen) gas supplied need to be monitored, the device is simple and can be easily executed. Therefore, it can be performed at low cost.

In addition, since it can be confirmed with certainty that the fuel cells and the lead film for which the reduction process has been insufficient have been lost, the start-up of the fuel cell system can be completed surely early. Therefore, it is possible to eliminate failures and unstable operating conditions, and improve reliability and stability.

In addition, even if the voltage of the fuel cell unit is abnormal, the load of the fuel gas is not suddenly cut off and the flow rate of the fuel gas 1 is gently controlled so that the fuel cell system is not overloaded. Is possible. Therefore, it becomes possible to have system reliability and long-term reliability.

[0131]

According to the present invention, by automatically controlling the hydrogen concentration according to the condition of the fuel cell, it is possible to perform stable reduction while confirming the voltage of the fuel cell and the like.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of first and second embodiments of a fuel cell system and a method of operating a fuel cell according to the present invention.

FIG. 2 is a diagram showing a relationship between an open circuit voltage, an outlet hydrogen concentration and an operating temperature in an embodiment of a fuel cell system and a fuel cell operating method according to the present invention.

FIG. 3 is a diagram showing another configuration of the first and second embodiments of the fuel cell system and the method of operating the fuel cell according to the present invention.

FIG. 4 is a diagram showing the relationship between the voltage and current of the fuel cell in the embodiment of the fuel cell system and the method of operating the fuel cell according to the present invention.

FIG. 5 is a diagram showing a relationship between a voltage of a fuel cell and an operating time in an embodiment of a fuel cell system and a fuel cell operating method according to the present invention.

FIG. 6 is a diagram showing a relationship between a voltage of a fuel cell unit and an operating time in a conventional example.

FIG. 7 is a diagram showing configurations of third and fourth embodiments of a fuel cell system and a fuel cell operating method according to the present invention.

FIG. 8 is a diagram showing another configuration of the third and fourth embodiments of the fuel cell system and the method of operating the fuel cell according to the present invention.

FIG. 9 is a diagram showing a relationship between an open circuit voltage, an outlet hydrogen concentration, and an operating temperature in an embodiment of a conventional technique.

FIG. 10 is a diagram showing a configuration of an embodiment of a conventional technique.

[Explanation of symbols]

1 fuel gas 2 Oxidizer gas 3 cell tube 4 Oxidant supply room 5 header 6 tube sheet A6 7 Tube plate B7 8 supply rooms 9 discharge chamber 10 Lead film 11 Fuel cells 12 guide tubes 13 Control unit 14 Gas sensor 15 Gas adjustment valve 16 Regulator valve control line 17 Measuring line A 18 Measuring line B 19 Fuel gas supply pipe 20 Fuel gas introduction pipe 21 Oxidant gas supply pipe 22 Oxidant gas discharge chamber 23 Fuel gas outlet pipe 24 Gas sensor line 25 Fuel gas exhaust pipe 26 Tube Sheet C 27 Tube Sheet D 28 Support A 29 Support B 110 header 110a partition plate 110b bottom plate 110c supply room 110d discharge chamber 111 cell tube 112 Guide tube

Continued front page    (72) Inventor Katsumi Nagata             1-1 Satinoura Town, Nagasaki City, Nagasaki Prefecture Mitsubishi Heavy Industries             Nagasaki Shipyard Co., Ltd. (72) Inventor Koji Ikeda             1-1 Satinoura Town, Nagasaki City, Nagasaki Prefecture Mitsubishi Heavy Industries             Nagasaki Shipyard Co., Ltd. F-term (reference) 5H026 AA06 CC06 CC10 CV02 CV06                       CX09 HH06                 5H027 AA06 KK25 KK31 KK51 KK54                       MM09

Claims (9)

[Claims] 1. A double-pipe structure having a fuel supply pipe for supplying the fuel gas, which has a gas adjusting portion for adjusting the flow rate of the fuel gas, an inner pipe having an open end and an outer pipe having a closed end. A fuel battery cell tube having fuel cells formed on the outer surface of the outer tube, and fuel gas from the fuel supply tube is folded back at the closed end through the inner tube, and the inner tube and the outer tube Flowing through, measuring the voltage of the fuel cell provided at the final end of the flow path of the fuel gas, based on the measurement result of the voltage,
A fuel cell system, comprising: a controller that controls the gas regulator. 2. A fuel supply pipe for supplying the fuel gas, the fuel supply pipe having a gas adjusting portion for adjusting the flow rate of the fuel gas, a fuel battery cell pipe having fuel battery cells formed on the surface of a base pipe, and the fuel supply pipe. From the fuel gas flowing through the fuel cell tube, the voltage of the fuel cell provided at the final end of the flow path of the fuel gas is measured, based on the measurement result of the voltage, the control of the gas adjustment unit A fuel cell system comprising: 3. A double pipe structure having a fuel supply pipe for supplying the fuel gas, having a gas adjusting portion for adjusting the flow rate of the fuel gas, an inner pipe having an open end and an outer pipe having a closed end. A fuel cell formed with a fuel cell on the outer surface of the outer tube and a lead film for taking out the generated electric power; Flow between the inner tube and the outer tube, to measure the resistance of the lead film provided at the final end of the flow path of the fuel gas, based on the measurement result of the resistance, A fuel cell system comprising: a control unit that performs control. 4. A fuel supply pipe for supplying the fuel gas, which has a gas adjusting portion for adjusting the flow rate of the fuel gas, a fuel cell on the surface of the base pipe, and a lead film for taking out the generated electric power. And the fuel cell from the fuel supply pipe, the fuel gas flows from the fuel cell pipe, the resistance of the lead film provided at the final end of the flow path of the fuel gas is measured, the measurement result of the resistance. And a control unit that controls the gas control unit based on the above. 5. A fuel discharge pipe for discharging the fuel gas, the fuel discharge pipe having a gas sensor for measuring a hydrogen concentration at the time of discharging the fuel gas, wherein the control unit has the voltage measurement result and the hydrogen. The fuel cell system according to any one of claims 1 to 4, wherein the gas regulator is controlled based on a result of concentration measurement. 6. The fuel cell system according to claim 1, wherein the fuel cell cell pipe supplies a smaller amount of fuel gas than other fuel cell cell pipes. 7. A step of supplying a fuel gas to a fuel cell formed on the surface of a substrate tube, and a step of measuring the voltage of the last fuel cell in the flow path of the fuel gas among the fuel cell. And a step of controlling the supply amount of the fuel gas based on the measurement result of the voltage, the fuel cell operating method. 8. A step of supplying a fuel gas to a lead film for taking out electric power generated by a fuel cell formed on a surface of a substrate tube, and a final lead film in the flow path of the fuel gas among the lead films. Measuring the resistance of the fuel cell, and controlling the supply amount of the fuel gas based on the measurement result of the resistance. 9. The method further comprising the step of measuring a hydrogen concentration when the fuel gas is discharged, wherein the step of controlling the supply amount of the fuel gas comprises the result of the voltage or resistance measurement and the hydrogen concentration measurement. The fuel cell operating method according to claim 7, which is performed based on the result.