JPH0644999A - Internally reformed type fuel cell - Google Patents

Abstract

PURPOSE:To enable reforming cetalyzer poisoned by sulfur, etc., to be regenerated easily and carbon separated out on the reforming catalyzer, etc., to be removed easily. CONSTITUTION:An indirect reforming section 21 having a reforming catalyzer 8 is provided in a position communicated to a fuel gas flow path 20a facing to a fuel gas electrode 2. In this internally reformed type fuel cell, an openable/ closable gas releasing hole 24 is provided between the fuel gas flow path 20a and the indirect reforming section 21. When the oxidation and combustion gas E2 for regeneration of the catalyzer is allowed to flow into the indirect reform section 21 so as to delete sulfur, carbon, etc., deposited to the reforming catalyzer 8 of the indirect reforming section 21, the oxidation and combustion gas E2 after regeneration is led into the gas releasing hole to prevent the gas E2 from flowing into the fuel gas flow path 20a.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an internal reforming type fuel cell in which a reforming catalyst for obtaining a reformed gas is built in a fuel cell using molten carbonate as an electrolyte.

[0002]

2. Description of the Related Art FIG. 7 shows, for example, Japanese Patent Laid-Open No. 62-237677.
FIG. 8 is a perspective view of a stack of a conventional internal reforming fuel cell shown in Japanese Patent Publication No. JP-A-2003-264, and FIG. 8 is an overall external view of this fuel cell.

In the figure, reference numeral 1 is an electrolyte matrix in which molten carbonate serving as an electrolyte is filled in porous ceramics, and 2 is made of, for example, porous nickel attached to one surface side of the electrolyte matrix 1. The fuel gas electrode 3 is attached to the other side of the electrolyte matrix 1, for example, an oxidant gas electrode made of porous nickel oxide, 4 is the electrolyte matrix 1, the fuel gas electrode 2 and the oxidant gas. The unit cell composed of the electrode 3 has a fuel gas flow path 5 on the fuel gas electrode 2 side.
a is a corrugated plate-like fuel gas flow channel plate, and 6 is a corrugated plate-shaped oxidant gas flow channel plate with the oxidant gas flow channel 6a facing the oxidant gas electrode 3 side. The fuel gas flow channel plate 5 and the oxidant gas flow channel plate 6 are made of a conductive material, and are provided with a plurality of punched holes (not shown).

Reference numeral 7 denotes a gas-tight conductive separator plate for partitioning the fuel gas flow channel plate 5 and the oxidant gas flow channel plate 6, and 8 is filled in the fuel gas flow channel 5a of the fuel gas flow channel plate 5. The reforming catalyst is a reforming catalyst, and the reforming gas reformed from the predetermined source gas by the reforming catalyst 8 is used as the fuel gas.
Supplied to the side. The fuel gas passage plate 5 having the reforming catalyst 8 constitutes an internal reforming section (direct reforming section) in the fuel cell.

Reference numeral 9 denotes a fuel gas seal frame in which the fuel gas electrode 2 and the fuel gas flow channel plate 5 are fitted, and 10 is an oxidant gas in which the oxidant gas electrode 3 and the oxidant gas flow channel plate 6 are fitted. A seal frame, 11 is a laminated body in which a plurality of unit cells 4, a fuel gas flow channel plate 5, an oxidant gas flow channel plate 6, a separator plate 7 and the like are vertically laminated, and 12 is a reforming gas that becomes a fuel gas in the laminated body 11. Inlet gas manifold for supplying the raw material gas of 1
3 is an outlet gas manifold for collecting the fuel exhaust gas that has passed through each fuel gas channel 5a of the laminated body 11, and 14 is the laminated body 11
An inlet gas manifold for supplying an oxidant gas to the.

Next, the operation of this fuel cell will be described. When the raw material gas composed of hydrocarbons (for example, methane) and water vapor is supplied to the fuel gas flow passage 5 a of the fuel gas flow passage plate 5 via the inlet gas manifold 12, the raw material gas causes the catalytic action of the reforming catalyst 8. Is converted into hydrogen (H ₂ ), carbon monoxide (CO) and carbon dioxide (CO ₂ ) by the reforming reaction represented by the formulas (1) and (2). CH ₄ + H ₂ O → CO + 3H ₂ (1) CO + H ₂ O → CO ₂ + H ₂ (2) In this case, the reaction heat required for the reforming reaction is the battery during power generation. The heat generated inside is used.

On the other hand, the oxidant gas in which air and carbon dioxide are mixed is supplied to the oxidant gas channel 6a of the oxidant gas channel plate 6 through the inlet gas manifold 14, and the oxidant gas in the oxidant gas Carbon dioxide and oxygen (O ₂ ) diffuse into the oxidant gas electrode 3 to cause a cathode reaction represented by the formula (3), and the carbonate ion (CO ₃ ²⁻ ) passes through the electrolyte matrix 1. Reaches the fuel gas electrode 2. _{CO 2 + 1 / 2O 2 +} 2e - → CO 3 2- ····· (3)

The hydrogen in the fuel gas generated by the reforming reaction diffuses into the fuel gas electrode 2 and is expressed by the formula (4) together with the carbonate ion that has moved from the oxidant gas electrode 3 through the electrolyte matrix 1. A anodic reaction occurs. ^{_{H 2 + CO 3 2- → H}} 2 O + CO 2 + 2e - ····· (4) Then, the electrochemical reaction consisting of the anode reaction and the cathode reaction, the fuel gas electrode 2 of the cell 4 containing gas A predetermined electromotive force is generated between the electrodes 3, and an electromotive force obtained by multiplying the electromotive force by the number of the unit cells 4 is generated in the stacked body 11 to which the unit cells 4 are connected in series. In addition,
The operating temperature of this fuel cell is about 650 ° C., and the above anode reaction and cathode reaction also proceed at this temperature.

Here, the anode reaction (4) occurs on the fuel gas electrode 2 side, hydrogen is consumed, and carbon dioxide and steam are produced. Therefore, the reforming reaction (1) is directed to reform methane. Move to. Therefore, in this internal reforming fuel cell having the reforming catalyst 8 in the fuel cell, about 6
As a reforming reactor having a temperature of 50 ° C., the raw material gas (methane) can be reformed by almost 100% although the temperature is relatively low.

[0010]

However, in the above-described conventional internal reforming fuel cell, the reforming catalyst 8 is poisoned by poisoning substances such as sulfur in the raw material gas, and the activity of the reforming catalyst 8 is reduced. There was a problem of lowering it. Particularly, when the reforming catalyst 8 is poisoned by sulfur, the adsorption of the raw material gas composed of methane or steam to the active sites of the reforming catalyst 8 is hindered because the sulfur adheres to the surface of the reforming catalyst 8, for example, nickel particles. It is caused by

Further, in the above conventional internal reforming type fuel cell, the hydrocarbon source gas is directly reformed in the fuel gas flow path 5a in the cell. Therefore, when trouble occurs in the steam supply system, reforming is performed. There is a problem that carbon is deposited on the catalyst 8 and the like, and the fuel gas flow path 5a is blocked by the carbon, so that the gas cannot be sufficiently flowed around the reforming catalyst 8.

The present invention has been made in order to solve the above problems, and it is possible to easily regenerate a reforming catalyst poisoned by sulfur and the like, and to deposit carbon deposited on the reforming catalyst. It is an object of the present invention to provide an internal reforming type fuel cell capable of easily removing hydrogen.

[0013]

According to a first aspect of the present invention, a fuel gas passage is provided facing a fuel gas electrode of a unit cell using molten carbonate as an electrolyte, and a fuel gas passage is provided facing an oxidant gas electrode. An internal reforming fuel in which an agent gas flow channel is provided and an indirect reforming section having a reforming catalyst for obtaining a reformed gas to be a fuel gas is provided at a position communicating with the fuel gas flow channel. In a cell, between the fuel gas flow path and the indirect reforming section, to prevent the oxidation / combustion gas for regenerating the reforming catalyst flowing in the indirect reforming section from flowing into the fuel gas flow path. That is, a gas discharge hole that can be opened and closed is provided.

In a second aspect of the present invention, a fuel gas passage is provided facing the fuel gas electrode of a unit cell using molten carbonate as an electrolyte, and an oxidant gas passage is provided facing the oxidant gas electrode 3. In the internal reforming fuel cell, which is provided with an indirect reforming section having a reforming catalyst for obtaining the reformed gas to be the fuel gas, the fuel gas Between the flow path and the indirect reforming section, an openable / closable gas release hole for preventing the oxidizing / combustion gas for regenerating the reforming catalyst flowing in the indirect reforming section from flowing into the fuel gas flow path. And a bypass passage for recycling the anode gas is provided between the gas discharge hole and the outlet of the fuel gas passage.

[0015]

In the first aspect of the present invention, the predetermined raw material gas supplied to the indirect reforming section is converted into the fuel gas by the reforming catalyst in the indirect reforming section and the heat generated from the unit cell due to power generation. The quality is improved, and this is moved to the fuel gas passage provided facing the fuel gas electrode to generate power. Then, when such a fuel cell is operated for a long period of time, the reforming catalyst in the indirect reforming section is poisoned by sulfur etc., its activity is lowered, and carbon is deposited around the reforming catalyst. This causes a decrease in the gas flow rate.

Therefore, in the indirect reforming section, oxidation / regeneration for catalyst regeneration is performed.
A regeneration process is performed in which a combustion gas (for example, air) is flown to oxidize and burn sulfur, carbon, and the like on the reforming catalyst to remove them.
In this case, the oxidizing / combusting gas, which has been subjected to the catalyst regeneration treatment, is discharged to the outside of the fuel cell from the gas discharge hole provided between the indirect reforming section and the fuel gas flow path facing the fuel gas electrode. To do. Therefore, the oxidizing / combusting gas does not enter the fuel gas passage and oxidize the fuel gas electrode or the like.

According to the second aspect of the present invention, the inlet side and the outlet side of the fuel gas passage are connected by a bypass passage, and the fuel gas (fuel exhaust gas) after power generation is again fed to the inlet side of the fuel gas passage. When recycling the anode gas that circulates to the inside, the bypass passage is formed by using the gas discharge hole for reforming the reforming catalyst in the indirect reforming section.

[0018]

Embodiments of the present invention will be described below with reference to the drawings. Example 1. The basic structure and operation of the internal reforming fuel cell according to the first aspect of the present invention will be described with reference to FIG. FIG. 1 is a diagram schematically showing a configuration around a fuel gas electrode of an internal reforming fuel cell. In the figure, the same or corresponding parts as those of the conventional internal reforming fuel cell shown in FIGS. 7 and 8 are designated by the same reference numerals, and the description thereof will be omitted.

In the figure, reference numeral 20 denotes a fuel gas flow path 20a facing the fuel gas electrode 2 side, and this fuel gas flow path 2
0a is a direct reformer that serves as a direct reforming section filled with the reforming catalyst 8 and has the same function as the fuel gas flow path plate 5 filled with the reforming catalyst 8 shown in FIG. Reference numeral 21 denotes an indirect reformer that serves as an indirect reformer in which the reforming catalyst 8 is filled in the gas flow passage 21a, and is a unit cell 4 including an electrolyte matrix 1, a fuel gas electrode 2 and an oxidant gas electrode 3. Alternatively, the gas flow passage 21a is arranged near the laminated portion and directly communicates with the fuel gas flow passage 20a of the reformer 20.

Reference numeral 22 is an inlet gas for distributing the partially reformed gas B partially reformed through the gas passage 21a of the indirect reformer 21 to the fuel gas passage 20a of the direct reformer 20. It is a manifold and has the same function as the inlet gas manifold 12 shown in FIG. An outlet gas manifold 23 collects the fuel exhaust gas D after the anode reaction (4) is generated in the finally reformed fuel gas C through the fuel gas passage 20a of the direct reformer 20,
It has the same function as the outlet gas manifold 13 shown in FIG. Reference numeral 24 is a gas release hole provided in the inlet gas manifold 22, 25 is an opening / closing valve of the gas release hole 24, and 26 is a gas capable of supplying the raw material gas A and the catalyst regeneration gas E to the gas flow passage 21a of the indirect reformer 21. It is a supply header.

Next, the operation of this internal reforming fuel cell and the procedure for regenerating the reforming catalyst 8 in the indirect reformer 21 will be described. For example, methane (C
The raw material gas A composed of H ₄ ) and steam is reformed while receiving heat from the neighboring unit cells 4 and this laminated portion in the process of passing through the gas flow passage 21a of the indirect reformer 21, and is partially reformed. It becomes the gas B and reaches the inlet gas manifold 22. The partial reformed gas B is supplied to the inlet gas manifold 22.
In the process of making a U-turn and directly passing through the fuel gas passage 20a of the reformer 20, the fuel gas C is reformed by almost 100%.

The hydrogen gas diffused in the fuel gas electrode 2 and the carbonate ions moving from the oxidant gas electrode 3 side to the fuel gas electrode 2 side in the electrolyte matrix 1 are electrically contained in the fuel gas C. Since it chemically reacts and changes into steam and carbon dioxide, it becomes a fuel exhaust gas D containing a large amount of this steam and carbon dioxide, and the outlet gas manifold 2
Reach 3. In this case, an electromotive force is generated between the fuel gas electrode 2 and the oxidant gas electrode 3.

Now, when this fuel cell is operated for a long time, the sulfur and the like contained in the raw material gas A, especially the indirect reformer 2
The reforming catalyst 8 in 1 adheres to the surface of nickel and deteriorates the reforming catalyst 8, leading to a reduction in the reforming rate in the indirect reformer 21. If a shortage of steam occurs in the raw material gas A due to a trouble in the steam supply system, the indirect reformer 21
Precipitation of carbon occurs on the reforming catalyst 8 and the like inside thereof, leading to deterioration of the function of the reforming catalyst 8 and increase of flow resistance in the gas flow passage 21a. Therefore, a procedure for regenerating the reforming catalyst 8 of the indirect reformer 21 will be described next. The regeneration operation of the reforming catalyst 8 is performed immediately after the operation of the fuel cell is stopped.

First, an inert gas E1 such as nitrogen is passed from the gas supply header 26 side into the indirect reformer 21, the direct reformer 20 or the like to purge the gas in the battery. Next, after opening the opening / closing valve 25 of the gas discharge hole 24, the air E2 as the oxidizing / combusting gas is flown from the gas supply header 26 into the indirect reformer 21. The air E2 receives the residual heat in the fuel cell to oxidize and burn the deteriorated reforming catalyst 8 in the indirect reformer 21,
The sulfur adhering to the nickel surface is changed to sulfur dioxide (SO ₂ ) to be removed, and at the same time, on the reforming catalyst 8 and the gas passage 21.
The carbon deposited in a is converted to carbon dioxide (CO ₂ ) and removed. In this case, the treated air E2 containing SO ₂ and CO ₂ does not flow directly to the reformer 20, but the gas release hole 2
4 is discharged to the outside of the fuel cell through the on-off valve 25. Therefore, the air E2 directly flows to the reformer 20 side, and the reforming catalyst 8 in the reformer 20 is directly oxidized by the oxygen in the air E2 or the fuel gas electrode 2 or the like is not oxidized. Absent.

Here, when the reforming catalyst 8 in the reformer 20 is directly oxidized, the electrolyte in the electrolyte matrix 1 is likely to adhere to the reforming catalyst 8, which causes inconvenience, and the fuel gas electrode 2 etc. Is not preferable from the viewpoint of corrosion of members. Since the air E2 does not flow directly into the reformer 20, it is not necessary to mix carbon dioxide for preventing decomposition of the carbonate in the electrolyte matrix 1 into the air E2.

Then, from the treated air E2, SO ₂ and C
When O ₂ is exhausted, the flow of the air E2 is stopped, and the inert gas E1 is again supplied from the gas supply header 26 side to the indirect reformer 21.
Flow to the side for gas purging. Next, hydrogen E3 is caused to flow from the gas supply header 26 side to reduce the reforming catalyst 8 in the indirect reformer 21, and then the inert gas E1 is again supplied from the gas supply header 26 side to the indirect reformer 21 side. The gas in the battery is purged by flowing it. And the on-off valve 2 of the gas outlet 24
5, the regeneration work of the reforming catalyst 8 in the indirect reformer 21 is completed.

If the catalyst regeneration operation using the air E2 is continued for a long time, oxygen in the air E2 diffuses directly into the reformer 20, the fuel gas electrode 2, etc., and oxidizes them. It is also possible to end up. In this case, the inert gas E is directed from the outlet gas manifold 23 directly into the reformer 20.
1 to prevent the oxygen in the air E2 from directly diffusing to the reformer 20 side. It should be noted that a small amount of hydrogen for reducing or carbon dioxide for preventing decomposition of the electrolyte in the electrolyte matrix 1 may be mixed in the inert gas E1. However,
The hydrogen concentration in the exhaust gas must be kept below the explosion limit.

In order to remove the sulfur adhering to the reforming catalyst 8, steam, instead of the air E2 for oxidation / combustion, is used.
Sulfur may be removed in the form of H ₂ S or the like using hydrogen or a gas containing a mixed gas of steam and hydrogen as a main component. In addition, in the case of hydrogen or the above mixed gas containing a certain proportion of hydrogen, the reforming catalyst 8 using hydrogen E3 after removal of sulfur is used.
There is no need to carry out the reduction work of.

Example 2. FIG. 2 shows an embodiment relating to a specific configuration of the internal reforming fuel cell according to the first aspect of the present invention.
And it demonstrates with reference to FIG. In the internal reforming fuel cell of this embodiment, an indirect reformer 21 is sandwiched every few cells in a laminated body similar to the laminated body 11 shown in FIG. Fuel gas flow path 5
It is of a type in which a is not filled with the reforming catalyst 8. That is, the reformer 20 is not directly incorporated in this internal reforming fuel cell.

FIG. 2 shows a fuel cell in which the gas flow direction in the indirect reformer 21 is opposed to the gas flow direction in the fuel gas flow passage 5a of the fuel gas flow passage plate 5. The raw material gas A supplied from the gas supply header 26 passes through the gas flow passages 21 a of each indirect reformer 21 and comes into contact with the reforming catalyst 8 to be converted into the fuel gas C, and then to the inlet gas manifold 22. Reach Then, the fuel gas C makes a U-turn at the inlet gas manifold 22 and passes through the inside of the fuel gas passage 5a of the fuel gas passage plate 5 while being converted into the fuel exhaust gas D and reaches the outlet gas manifold 23. Regeneration of the reforming catalyst 8 of the indirect reformer 21 is performed by using the gas release hole 24 provided in the inlet gas manifold 22. Therefore, the oxidizing / combusting air E2 does not flow into the fuel gas passage 5a of the fuel gas passage plate 5.

FIG. 3 shows a fuel cell in which the gas flow direction in the indirect reformer 21 is opposed to the gas flow direction in the oxidant gas flow path 6a of the oxidant gas flow path plate 6. There is.
The raw material gas A supplied from the gas supply header 26 is converted into the fuel gas C by the indirect reformer 21, and then reaches the inlet gas manifold 22 through the gas discharge header 27. Then, the fuel gas C is converted from the inlet gas manifold 22 into the fuel exhaust gas D while passing through the fuel gas flow passage 5 a of the fuel gas flow passage plate 5 and reaches the outlet gas manifold 23. Further, the regeneration of the reforming catalyst 8 in the indirect reformer 21 is performed by the gas release hole 2 provided in the inlet gas manifold 22.
4 is used.

Example 3. Another embodiment relating to the specific structure of the internal reforming fuel cell according to the first aspect of the present invention will be described with reference to FIG. The internal reforming fuel cell according to this embodiment includes a pair of indirect reformer 21 and direct reformer 20 in place of the fuel gas flow path plate 5 in a laminated body similar to the laminated body 11 shown in FIG. Is a built-in type. The stacking of the unit cells 4 is considered to be directly on the reformer 20 side.

The raw material gas A supplied from the gas supply header 26 passes through the gas flow passages 21a of each indirect reformer 21 and comes into contact with the reforming catalyst 8 to be converted into the partial reformed gas B,
Reach the inlet gas manifold 22. The reformed gas B is turned in the inlet gas manifold 22 and directly converted into the fuel gas C while passing through the fuel gas passage 20a of the reformer 20, and the fuel gas C is further converted into the fuel exhaust gas D. It is changed to reach the outlet gas manifold 23. Further, the regeneration of the reforming catalyst 8 in the indirect reformer 21 is performed by using the gas release hole 24 provided in the inlet gas manifold 22. Therefore, the oxidizing / combusting air E2 does not flow directly into the fuel gas passage 20a of the reformer 20. The indirect reformer 21 may be provided not only beside the direct reformer 20 but also beside the unit cell 4.

Example 4. Another embodiment relating to the specific configuration of the internal reforming fuel cell according to the first aspect of the present invention will be described with reference to FIG. The internal reforming fuel cell according to this embodiment has the same laminated body as the laminated body 11 shown in FIG. 7, but is of a type in which an indirect reformer 21 is installed in the inlet gas manifold 22. is there. The filling amount of the reforming catalyst 8 in the fuel gas passage 5a of the fuel gas passage plate 5 is reduced by the amount of the indirect reformer 21 attached.

The raw material gas A supplied to the inlet gas manifold 22 is converted into a partial reformed gas B by coming into contact with the reforming catalyst 8 while passing through the gas flow passage 21a of the indirect reformer 21, and then entering the inlet. It reaches the downstream portion 22 a of the gas manifold 22. Heat is transferred to the indirect reformer 21 by radiation from the wall surface of the battery stack and conduction from the wall surface of the inlet gas manifold 22 to accelerate the reforming reaction. Then, the reformed gas B reaching the downstream portion 22a flows into the fuel gas passage 5a of each fuel gas passage plate 5, is converted into the fuel gas C while passing through the fuel gas passage 5a, and thereafter. The fuel gas C is further converted into the fuel exhaust gas D and reaches the outlet gas manifold 23. Further, the reforming of the reforming catalyst 8 in the indirect reformer 21 is performed by using the gas release hole 24 provided in the downstream portion 22a of the inlet gas manifold 22. Therefore, the air E for oxidation and combustion
2 does not flow into the fuel gas channel 5a of the fuel gas channel plate 5.

Example 5. An embodiment of the internal reforming type fuel cell according to the second aspect of the present invention will be described with reference to FIG. The fuel cell according to this embodiment has the same structure as that of the fuel cell according to the third embodiment, such as the laminated body and the gas discharge holes 24.
It is different from the fuel cell of Example 3 in that the anode gas is recycled.

In the figure, 28 is a gas discharge pipe continuing from the gas discharge hole 24, 29 is a gas recycle pipe provided from the outlet gas manifold 23 to the gas discharge hole 24 including the gas discharge pipe 28, and 30 is a recycled fuel exhaust gas D. A blower 31 for supplying the gas, a gas supply pipe 31 for supplying a new raw material gas A at the time of gas recycling by using the gas discharge hole 24, and 32, 33, 34, 35 are opening / closing valves, respectively.

On-off valve 3 is used for gas recycling.
2 and 35 are opened, the blower 30 is driven, and the fuel exhaust gas D in the outlet gas manifold 23 is fed into the gas recycle pipe 2
9. Inlet gas manifold 2 via gas discharge hole 24
In addition to being circulated to 2, the on-off valve 33 is opened and new raw material gas A is supplied to the inlet gas manifold 22. As a result, the steam or the like in the circulated fuel exhaust gas D is fully utilized, and the raw material gas A is directly reformed by the reformer 20. Here, when the gas is recycled, the fuel exhaust gas D is generated by the evaporation of the electrolyte from the electrolyte matrix 1.
Although it has an electrolyte component therein, since the fuel exhaust gas D is directly circulated only to the reformer 20 side, the reforming catalyst 8 in the direct reformer 20 is protected from the electrolyte component and the catalyst can be regenerated. Becomes Even when the gas recycle operation is performed, the raw material gas A (quantitatively reduced from the case of the third embodiment) is supplied from the gas supply header 26 to the indirect reformer 21 side. The source gas A is also reformed by 21.

Regeneration of the reforming catalyst 8 in the indirect reformer 21 is performed by closing the opening / closing valve 33 and opening the opening / closing valves 32 and 34, and the air E2 for oxidation / combustion is discharged through the gas release hole 24.
And, it is discharged to the outside of the fuel cell through the gas discharge pipe 28.

When the anode gas is recycled as described above, the gas release hole 24 and the gas release pipe 28 for catalyst regeneration of the indirect reformer 21 attached to the inlet gas manifold 22 can be used, and the size of the apparatus can be reduced. Can be achieved.

[0041]

Since the present invention is constituted as described above, it has the following effects.

According to the first aspect of the present invention, the fuel gas passage is provided so as to face the fuel gas electrode of the unit cell using molten carbonate as an electrolyte, and the oxidant gas passage is provided so as to face the oxidant gas electrode. And an indirect reforming section having a reforming catalyst for obtaining a reformed gas to be the fuel gas is provided at a position communicating with the fuel gas flow path, Between the gas flow path and the indirect reformer,
Oxidation to regenerate the reforming catalyst flowed to the indirect reforming section
When the oxidizing / combusting gas is used to regenerate the reforming catalyst in the indirect reforming section, the open / close gas release holes are provided to prevent the burning gas from flowing into the fuel gas flow path. It is possible to regenerate the reforming catalyst by discharging the oxidizing / combusting gas into the gas discharge hole without flowing it into the fuel gas passage. Therefore, the reforming catalyst poisoned by sulfur or the like can be easily regenerated, and the carbon deposited on the reforming catalyst or the like can be easily removed.

According to the second aspect of the present invention, the fuel gas flow path is provided facing the fuel gas electrode of the unit cell using molten carbonate as the electrolyte, and the oxidant gas flow facing the oxidant gas electrode 3 is provided. In the internal reforming fuel cell in which the passage is provided, an indirect reforming unit having a reforming catalyst for obtaining the reformed gas to be the fuel gas is provided at a position communicating with the fuel gas flow path, Between the fuel gas flow path and the indirect reforming section, openable and closable to prevent the oxidizing / combustion gas for regenerating the reforming catalyst flowed to the indirect reforming section from flowing into the fuel gas flow path. Since the gas discharge hole is provided and the bypass passage for anode gas recycling is provided between the gas discharge hole and the outlet of the fuel gas passage, the same effect as that of the first invention can be obtained. When performing anode gas recycling , It is possible to reduce the size of the device can use the gas discharge hole as part of the bypass passage.

[Brief description of drawings]

FIG. 1 is a diagram illustrating the basic configuration and operation of an internal reforming fuel cell according to the first aspect of the present invention.

FIG. 2 is a diagram showing a first specific structure of the internal reforming fuel cell according to the first invention of the present invention.

FIG. 3 is a diagram showing a second specific structure of the internal reforming fuel cell according to the first invention of the present invention.

FIG. 4 is a diagram showing a third specific structure of the internal reforming fuel cell according to the first invention of the present invention.

FIG. 5 is a diagram showing a fourth specific configuration of the internal reforming fuel cell according to the first invention of the present invention.

FIG. 6 is a diagram showing a specific configuration of an internal reforming fuel cell according to a second invention of the present invention.

FIG. 7 is a perspective view of a stack of a conventional internal reforming fuel cell.

FIG. 8 is a perspective view of a conventional internal reforming fuel cell.

[Explanation of symbols]

 2 Fuel Gas Electrode 4 Single Cell 5a Fuel Gas Flow Path 8 Reforming Catalyst 20a Fuel Gas Flow Path 21 Indirect Reformer (Indirect Reforming Section) 24 Gas Release Hole 29 Gas Recycle Pipe (Gas Recycle Path) C Fuel Gas E2 Air (Oxidation / combustion gas)

[Procedure amendment]

[Submission date] November 2, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0038

[Correction method] Change

[Correction content]

On-off valve 3 is used for gas recycling.
2 and 35 are opened, the blower 30 is driven, and the fuel exhaust gas D in the outlet gas manifold 23 is fed into the gas recycle pipe 2
9. Inlet gas manifold 2 via gas discharge hole 24
And it is recycled to the 2 and monitor, on-off valve 33 is opened to supply a new raw material gas A to the inlet gas manifold 22. this
The new raw material gas A does not need to contain steam in advance. As a result, the steam or the like in the circulated fuel exhaust gas D is fully utilized, and the raw material gas A is directly reformed by the reformer 20. Here, when the gas is recycled, the fuel exhaust gas D is generated by the evaporation of the electrolyte from the electrolyte matrix 1.
Although it has an electrolyte component therein, since the fuel exhaust gas D is directly circulated only to the reformer 20 side, the reforming catalyst 8 in the indirect reformer 21 is protected from the electrolyte component and the catalyst can be regenerated. Becomes Even when the gas recycle operation is performed, the raw material gas A (quantitatively reduced from the case of the third embodiment) is supplied from the gas supply header 26 to the indirect reformer 21 side. The source gas A is also reformed by 21.

Claims (2)

[Claims] 1. A fuel gas flow path is provided facing a fuel gas electrode of a unit cell using molten carbonate as an electrolyte, an oxidant gas flow path is provided facing an oxidant gas electrode, and the fuel is In an internal reforming type fuel cell in which an indirect reforming unit having a reforming catalyst for obtaining a reformed gas to be a fuel gas is provided at a position communicating with the gas flow channel, An openable / closable gas discharge hole for preventing the oxidizing / combustion gas for regenerating the reforming catalyst flowed to the indirect reforming section from flowing into the fuel gas passage between the quality control section and the quality section. An internal reforming type fuel cell characterized by being provided with. 2. A fuel gas flow path is provided facing a fuel gas electrode of a unit cell using molten carbonate as an electrolyte, an oxidant gas flow path is provided facing an oxidant gas electrode 3, and the fuel gas flow path is provided. In an internal reforming fuel cell in which an indirect reforming section having a reforming catalyst for obtaining a reformed gas to be a fuel gas is provided at a position communicating with the fuel gas flow channel, Between the reforming sections, openable / closable gas release holes for preventing the oxidizing / combusting gas for regenerating the reforming catalyst flowed to the indirect reforming section from flowing into the fuel gas passage. An internal reforming fuel cell, wherein a bypass passage for anode gas recycling is provided between the gas discharge hole and the outlet of the fuel gas passage.