JPH05144459A - Fuel cell power generating system of molten carbonate type - Google Patents

Abstract

PURPOSE:To collect a gas including detrimental components with bad smell without releasing to the outside. CONSTITUTION:A fuel cell power generating system consists of a molten carbonate type fuel cell 10, in which a plurality of unitary cells each consisting of an anode, cathode and electrolyte plate installed between them are atacked with separators interposed, and gas component collecting devices 30, 31 which are coupled with the exhaust side of the fuel cell 10 and which cool and solidify the gas generated with decomposition of a molding aid agent included in the anode, cathode, and electrolyte plate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molten carbonate fuel cell power generation system, and more particularly, to a harmful component in a gas generated by decomposition of a forming aid contained in an anode, a cathode and an electrolyte plate constituting a unit cell. The present invention relates to a molten carbonate fuel cell power generation system having a cooling and solidifying mechanism.

[0002]

2. Description of the Related Art The basic structure of a molten carbonate fuel cell is shown in FIG.
Shown in. Between an anode (fuel electrode) 1 and a cathode (air electrode) 2 which are a pair of electrodes having conductivity, an electrolyte plate 3 holding an electrolyte composed of an alkali carbonate is sandwiched and arranged. .. Two housings 4a and 4b are brought into contact with the peripheral edges of both surfaces of the electrolyte plate 3,
The anode 1 and the cathode 2 are housed in a and b, respectively. Corrugated current collecting plates 5a and 5b are provided between the inner surface of the one housing 4a and the anode 1 and between the inner surface of the other housing 4b and the cathode 2, respectively.
Are arranged. A supply port 6 for supplying fuel gas (H ₂ , CO ₂ ) to the anode 1 and exhaust gas (CO ₂ , H ₂ O) are provided in the one housing 4 a in which the anode 1 is located. The exhaust ports 7 for exhausting the air are opened respectively. In the other housing 4b in which the cathode 2 is located, a supply port 8 for supplying an oxidant gas (air, CO ₂ ) to the cathode 2 and an exhaust gas (N ₂ ) are exhausted. The respective exhaust ports 9 are opened.

[0003] molten carbonate charge battery shown in FIG. 1 described above, to melt the mixed alkali carbonate electrolyte plate 3 at a high temperature, anode - fuel gas through the supply port 6 of the housing 4a to de 1 (H ₂ , CO ₂ ) and oxidant gas (air, CO ₂ ) are supplied to the cathode ₂ through the supply port 8 of the housing 4b, and the reaction of the formula (1) below is performed by the anode 1 to the cathode 2 The operation is performed by causing the reaction of the following equation (2). ^{_{H 2 + CO 3 2- → H}} 2 O + CO 2 + 2e - … (1) 1/2 O ₂ + CO ₂ + 2e ⁻ → CO ₃ ^2- … (2)

By the way, since the molding aid is included in the molding of the anode, cathode and electrolyte plate which are the cell constituent members of the molten carbonate fuel cell, the fuel cell was incorporated. In the power generation system, it is necessary to remove the molding aid at the time of startup before operation.

Conventionally, as a method of removing the molding aid, it has been practiced to heat each of the cell constituent members to gasify the molding aid, and then discharge the gas to the outside or burn it. However, the molding aid is generally composed of an organic binder and a plasticizer, and is added to each of the cell constituent members in an amount of 20 to 40.
Since it is blended by weight, a huge amount of gas is generated during the heat treatment. Since the gas contains harmful components, if exhausted as it is, there arises a problem of environmental pollution. Further, in the method of burning the gas, the system becomes large in size, the processing cost rises, and the gas processing itself is very difficult.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a molten carbonate fuel cell power generation system equipped with a device for collecting a gas containing a harmful component accompanied by an offensive odor without exhausting it to the outside. ..

[0007]

The present invention relates to a molten carbonate fuel cell in which a plurality of unit cells each consisting of an anode, a cathode and an electrolyte plate arranged between them are laminated with a separator interposed therebetween, and A molten carbonate fuel cell, comprising: a gas component recovery device connected to the exhaust side, the gas component recovery device for cooling and solidifying a gas generated by decomposition of the forming aid contained in the anode, the cathode and the electrolyte plate. It is a power generation system.

The gas component recovery device preferably has a structure in which a plurality of filters having physical adsorption, chemical adsorption, or both functions are arranged at a desired distance.

Examples of the filter material include granular filter material (anthrite, sand, granular activated carbon, magnetite), sintered metal, ceramics, natural fiber, synthetic fiber, metal fiber,
Alternatively, a carbon adsorbent, a zeolite adsorbent, a silica alumina adsorbent, or the like can be used.

It is desirable that the filter be used properly according to the molecular diameter of the gas. For example, a filter made of sintered metal, ceramics, natural fiber, synthetic fiber, or metal fiber is used to recover a gas with a large molecule, and a carbon adsorbent or a zeolite-based filter is used to recover a gas with a small molecule. A filter composed of an adsorbent and a silica-alumina adsorbent is used.

When arranging the plurality of filters, it is desirable that the filters having different pore diameters are arranged such that the filter having a larger pore diameter is located from the gas inlet side toward the gas outlet toward the inlet.

In the power generation system according to the present invention, it is possible to dispose the heating means for keeping the temperature of the pipe for connecting the fuel cell and the gas component recovery device with each other. As the heating means, for example, a heater arranged on the outer periphery of the pipe or a pipe through which a high temperature gas wound around the pipe flows can be adopted.

[0013]

According to the present invention, the gas component recovery device is provided on the exhaust side of the fuel cell, and the gas generated by the decomposition of the molding aid contained in the cell constituent member of the fuel cell is introduced into the recovery device. By solidifying by cooling with, it is possible to prevent a large amount of gas containing harmful components from being discharged to the outside. Moreover, large-scale equipment is not required as compared with the conventional method of burning gas, the system itself can be simplified, and the running cost can be remarkably reduced.

Further, if a heating means is provided in the pipe for connecting the fuel cell and the recovery device to each other, it becomes possible to keep the temperature of the pipe by the heating means. As a result, it can be introduced into the recovery device in a gas state,
It is possible to prevent the adhesion of slag, tar, etc., which causes the components in the gas to be deposited on the inner surface of the pipe and causes the pipe to be blocked.

[0015]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 2 is a schematic view showing a main part of the power generation system of this embodiment, FIG. 3 is a perspective view showing a molten carbonate fuel cell incorporated in the power generation system of FIG. 2, and FIG. FIG. 5 is an enlarged perspective view of a main part of the fuel cell, and FIG. 5 is a perspective view showing a recovery device.

The molten carbonate fuel cell 10 incorporated in the power generation system of FIG. 2 has an anode (fuel electrode) 11, a cathode (air electrode) 12 and these electrodes as shown in FIGS. 3 and 4. An electrolyte plate 13 that holds the electrolyte and is disposed between 11 and 12 is provided. These Anode 11, Casso
The battery 12 and the electrolyte plate 13 are used as a unit cell, and a plurality of unit cells are stacked with the separator 4 interposed therebetween. The pair of opposite edges of the anode 11 arranged on the upper surface of the electrolyte plate 13 are positioned inside the edge of the electrolyte plate 13 to a desired distance, and the anode 11 is not present. Edge seal plates 15 a are arranged between both edges of the electrolyte plate 13 and the separator 14. A pair of edge portions of the cathode 12 disposed on the lower surface of the electrolyte plate 13 orthogonal to the edge seal plate 15a are located inside the cathode plate 13 at a desired distance from the edge portion of the electrolyte plate 13. Between the both edges of the electrolyte plate 13 where the cathode 12 does not exist and the separator 14, an edge seal plate 15b is provided.
Are arranged. The node 11 and the separator 14
In the space defined by the edge seal plate 15a (fuel gas distribution space), a perforated plate 16a having conductivity as a current collector plate and a corrugated plate 17a are sequentially laminated from the anode 11 side. .. In the space (oxidant gas distribution space) defined by the cathode 12, the separator 14 and the edge seal plate 15b, a perforated plate 16b having conductivity and a corrugated plate 17b as a current collecting plate are provided. The layers are sequentially stacked from the side of the cathode 12.

A plurality of such unit cells are used in the separator 1.
Manifolds 19 each having a frame-shaped flange 18 are arranged on the four side surfaces of the stacked power generation elements that are stacked with four sandwiched therebetween. Further, frame-shaped manifold seal plates 20 are respectively interposed between the four side surfaces of the stack power generation element and the flange 18 of the manifold 19. A supply pipe 22 for supplying the fuel gas 21 is attached to a manifold (not shown) corresponding to the side surface of the power generation element where the fuel gas flow space is exposed. A gas exhaust pipe 23 is attached to the manifold 19 on the side opposite to the supply pipe 22. A supply pipe 25 for supplying the oxidant gas 24 is attached to a manifold (not shown) corresponding to the side surface of the power generating element where the oxidant gas flow space is exposed. In the manifold 19 on the opposite side of the supply pipe 25,
The gas exhaust pipe 26 is attached. An orthogonal transformation device 27 is connected to the fuel cell 10.

The gas discharge pipes 23 and 26 are provided with a valve 2
8 and 29 are respectively interposed. Each valve 2
Gas component recovery devices 30 and 31 are provided in the pipes 8 and 29, respectively.
2, 33, and exhaust pipes 34, 35 are connected to the recovery devices 30, 31, respectively.
The three-way valve 2 of the gas exhaust pipes 23 and 26
Air pipes (not shown) are respectively wound around the points 8 and 29 and the pipes 32 and 33, and high-temperature air is circulated in the air pipes.

The gas component recovery devices 30 and 31 are shown in FIG.
The box-shaped container 36 having an open bottom as shown in FIG.
A sheet heater 37 is provided around the periphery of the container 36 except the front surface and the back surface. On the front surface of the container 36,
The pipe 32 is connected and the exhaust pipe 34 is provided on the back side.
Are connected. Within the container 36, for example, four filter 38 _{1-38 4} equidistant, and the container 36
Are arranged parallel to the front surface of the. Each filter 38 _{1-38 4} is formed of sintered nickel. The filter 38 located on the side close to the pipe 32
₁ has a pore size of 5000 Å and a porosity of 72%. The filter 38 ₄ located on the side closer to the exhaust pipe 34 has a pore size of 1000 angstroms
It has a porosity of 0%. The filters 38 ₂ and 38 ₃ located between the filters 38 ₁ and 38 ₄ have a hole diameter of 30.
It has a porosity of 50% at 00 angstroms. A liquid storage member 39 that stores tar and the like is detachably provided below the container 36.

In the power generation system as described above, the fuel gas 21 consisting of a mixed gas of hydrogen (H ₂ ) and carbon dioxide (CO ₂ ) is supplied through the supply pipe 22 to the fuel cell 10
On the anode 11 side of, for example, air and carbon dioxide (C
Oxide gas 24 consisting of a mixed gas with O ₂ ) is supplied to the supply pipe 2
The forming aids supplied to the cathode 12 side of the fuel cell 10 through 5 and contained in the cell constituent members cathode 11, anode 12 and electrolyte plate 13 are vaporized and gasified. The gas is discharged through the gas discharge pipes 23, 26.
By operating the valves 28 and 29, respectively, which are installed in the gas component recovery devices 30 and 31, they are introduced through the gas discharge pipes 23 and 26 and the pipes 32 and 33, respectively. When introducing such a gas into the respective gas component recovery devices 30, 31, the gas discharge pipes 23, 26, the pipe 32,
Since 33 is wound with an air pipe (not shown) in which air heated to 300 ° C to 500 ° C is circulated, each of the pipes is kept warm and slag and the like are prevented from adhering to the inner surface thereof. To be prevented.

The gas introduced into each of the gas component recovery devices 30 and 31 is introduced into the gas while passing through, for example, four filters 38 _{1 to} 38 ₄ arranged in a container 36 as shown in FIG. The contained components are trapped and the clean gas is exhausted through the exhaust pipes 34, 35 of the recovery devices 30, 31. The gas components are added to the filters 38 _{1 to} 3
8 After trap _4, each filter 38 _{1-38 4} by the planar heater 37 arranged on the outer periphery of the container 36
By heating the whole, the slag and tar trapped in them are liquefied, collected in the liquid storage member 39 below the container 36, cooled and solidified to room temperature, and collected.

Therefore, according to the present embodiment, the forming aid contained in the cell constituent members of the fuel cell 10 is gasified, and the gas discharge pipes 23, 26 and valves corresponding to the cathode 11 and the anode gas 12 of the fuel cell 10 are gasified. 28, 29 and piping 3
By introducing the gas component recovery devices 30, 31 through 2, 33, it is possible to exhaust a clean gas containing no harmful component from the exhaust pipes 34, 35 which are the outlets of the gas component recovery devices 30, 31. the harmful components can be trapped by the filter 38 _{1-38 4,} liquefied by the heater 37, the harmful components by cooling and solidifying in the liquid reservoir member 38 sludge can be recovered as a tar. In fact, as a result of analyzing the components of the recovered substance, it was confirmed that the substance was the same as the molding aid added to the cell constituent member.

Further, the air heated to 300 ° C. to 500 ° C. is circulated through the gas discharge pipes 23, 26 and the pipes 32, 33 which are introduction paths from the fuel cell 10 to the gas component recovery devices 30, 31. By winding an air pipe (not shown), the gas exhaust pipes 23, 26, the pipes 32, 33 can be kept warm, preventing slag and the like from adhering to and blocking the inner surfaces of the pipes. can do.

Furthermore, the respective gas component recovery devices 30, 3
If the filter 38 ₁ having the largest pore size on the gas inlet side and the filters 38 ₂ , 38 ₃ , 38 ₄ having smaller pore sizes toward the outlet side are sequentially arranged in the container 36 of No. ₁ , the harmful gas It becomes possible to trap the components more efficiently.

In the above-mentioned embodiment, an air pipe (not shown) in which heated air is circulated is wound around a gas exhaust pipe or the like which is an introduction path from the fuel cell to each gas component recovery device.
Instead of the air tube, for example, a ribbon heater may be wound to keep each tube warm as in the embodiment.

[0027]

As described above in detail, according to the molten carbonate fuel cell power generation system of the present invention, a gas containing a harmful component having an offensive odor can be collected without being discharged to the outside, and environmental pollution can be prevented. As compared with the conventional method of burning gas, large-scale equipment is not required, the system itself can be simplified, and running costs can be remarkably reduced.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing the basic structure of a molten carbonate fuel cell.

FIG. 2 is a schematic diagram showing a main part of the power generation system of the present embodiment.

3 is a perspective view showing a molten carbonate fuel cell incorporated in the power generation system of FIG.

FIG. 4 is an enlarged perspective view of a main part of the fuel cell of FIG.

5 is a perspective view showing a gas component recovery device incorporated in the power generation system of FIG.

[Explanation of symbols]

10 ... Molten carbonate fuel cell, 11 ... Anode, 12 ...
Cathode, 13 ... Electrolyte plate, 14 ... Separator, 19 ...
Manifold, 21 ... Fuel gas, 22, 25 ... Supply pipe,
24 ... Oxidizing gas, 23, 26 ... Gas exhaust pipe, 28, 2
9 ... valve, 30 and 31 ... gas component recovery device, 37 ... plane heater, 38 _{1-38 4} ... filter, 39 ... liquid reservoir member.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kazuaki Nakagawa 1 Komukai Toshiba-cho, Kouki-ku, Kawasaki-shi, Kanagawa Incorporated Toshiba Research Laboratory

Claims (1)

[Claims] 1. A molten carbonate fuel cell in which a plurality of unit cells composed of an anode, a cathode and an electrolyte plate arranged between them are laminated with a separator interposed between the molten carbonate fuel cell and the exhaust side of the fuel cell. A molten carbonate fuel cell power generation system, comprising: a cathode, and a gas component recovery device for cooling and solidifying a gas generated by decomposition of a molding aid contained in the electrolyte plate.