JPH0620711A - Inside reform unit for indirectly inside-reforming fused carbonate type fuel cell - Google Patents

Abstract

PURPOSE:To provide an inside reform unit for an indirectly inside-reforming fused carbonate type fuel cell, which can get equal contact with an electrode by dispersing fastening pressure almost equally. CONSTITUTION:In an inside reform unit 1 for an indirect inside-reforming fused carbonate type fuel cell, which has an inside reform unit body where the frame body 10 is filled up with a reform catalyst 8 and a material gas partition plate 7 for controlling the direction of the flow of material gas is provided at the center of this frame body 10 and upper and lower seal plates 11a and 11b attached to this inside reform unit body, the material partition plate 7 is constituted of an elastic member capable of being elastically deformed up and down.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an internal reforming unit for an indirect internal reforming molten carbonate fuel cell, and more particularly to improving the structure of a raw material gas partition plate of the internal reforming unit.

[0002]

2. Description of the Related Art A molten carbonate fuel cell has an operating temperature of about 6
Since the temperature is as high as 50 ° C and is close to 800 ° C, which is the reforming temperature of natural gas (main component: methane) normally used as a fuel, an internal reforming method for reforming the fuel in the cell stack is possible. is there. This internal reforming system can be made compact because a fuel reforming device is unnecessary, and heat and water generated during the cell reaction can be used as heat and water necessary for the reforming reaction. Due to such excellent features, higher power generation efficiency can be expected compared to the external reforming method.

The internal reforming system is classified into a direct internal reforming system and an indirect internal reforming system depending on the method of arranging the reforming catalyst. The former is a cell in which a reforming catalyst is installed in the fuel gas passage on the back of the fuel electrode, and since the reforming catalyst is installed in a place where hydrogen is consumed, higher reforming efficiency and higher power generation efficiency can be expected. However, there is a problem that the reforming catalyst is easily contaminated by the molten carbonate in the electrolyte and the characteristics are largely deteriorated. On the other hand, the latter is a battery in which a reforming container filled with a reforming catalyst is installed in every few cells (usually 3 to 6 cells), and the reforming container (that is, the reforming catalyst) and the electrolyte (that is, molten carbonate). ) And are separated from each other, there is no problem of contamination of the reforming catalyst by the molten carbonate as in the former, and a long life can be expected.

By the way, as shown in FIGS. 5 and 6, the internal reforming unit used in the conventional indirect internal reforming molten carbonate fuel cell has a raw material gas introduction pipe for introducing the raw material gas into the reforming unit. 61, and a raw material gas partition plate 71 for controlling the flow of the raw material gas introduced from the raw material gas introduction pipe 61 so that the reforming reaction in the reforming unit becomes uniform.
Reforming catalyst section 8 arranged around this source gas partition plate 71
4 (that is, a laminated portion of the corrugated plate 82 and the gas separation plate 83) and a frame-shaped frame body 100 that surrounds the peripheral surface of the reforming catalyst portion 84, and the internal reforming unit main body. It is composed of sealing plates 110a and 110b attached to both upper and lower surfaces of the unit body. The source gas partition plate 71 is configured to have the same height dimension as that of the frame body 100, and the upper and lower surfaces of the control wall 71 are welded to the upper and lower sealing plates 110a and 110b, respectively.
One end of is welded to the inner surface of the frame 100.

[0005]

However, in the conventional internal reforming unit shown in FIGS. 5 and 6, the upper and lower sealing plates 110a.
When attaching 0b to form a stack, the following problems occur. That is, when the height dimension of the reforming catalyst portion 84 provided between the frame body 100 and the source gas partition plate 71 is lower than the height dimension of the frame body 100 and the source gas partition plate 71. , Upper and lower sealing plates 110a, 110
When attaching b, the tightening pressure is concentrated on the source gas partition plate 71. Therefore, the internal reforming unit and each electrode do not come into uniform contact with each other, and the current flows concentratedly in the region corresponding to the source gas partition plate 71 and the frame body 100, so that stable battery characteristics cannot be obtained. Has the problem. When the height dimension of the reforming catalyst portion 84 is higher than the height dimension of the frame body 100 and the source gas partition plate 71, the upper and lower sealing plates 110a.
When 110b is attached to form a stack, the elastic reforming catalyst portion 84 contracts until the height is substantially the same as the height of the frame 100 and the source gas partition plate 71. Therefore, the tightening pressure is substantially evenly distributed, and the above-mentioned problem does not occur.

In view of the above-mentioned problems, the present invention provides an internal reforming unit of an indirect internal reforming molten carbonate fuel cell, which can disperse tightening pressure substantially evenly and obtain uniform contact with an electrode. The purpose is to

[0007]

In order to solve the above-mentioned problems, the present invention is provided with a reforming catalyst in a frame body, and a raw material gas partition plate for controlling the flow direction of the raw material gas is provided in the central portion of the frame body. In the internal reforming unit of the indirect internal reforming molten carbonate fuel cell having the internal reforming unit main body and the upper and lower sealing plates attached to the internal reforming unit main body, the source gas partition plate is arranged in the vertical direction. It is characterized in that it is composed of an elastic member that is elastically deformable.

[0008]

According to the above structure, since the raw material gas partition plate is made of the elastic member, the height dimension of the reforming catalyst portion (that is, the laminated portion of the corrugated plate and the separation plate) is the raw material gas partition plate. The height of the reforming catalyst section (ie,
It is elastically deformed so that it has the same height as the laminated portion of the corrugated plate and the separation plate. Therefore, when the upper and lower sealing plates are attached to form a stack, the tightening pressure is not concentrated on the source gas partition plate as in the conventional case, but is substantially evenly distributed. As a result, the internal reforming unit comes into contact with each electrode substantially uniformly, so that stable battery characteristics can be obtained for a long period of time.

[0009]

【Example】

(First Embodiment) FIG. 1 is a schematic view of an indirect internal reforming molten carbonate fuel cell using an internal reforming unit according to the first embodiment of the present invention, and FIG. 2 is an exploded perspective view of the internal reforming unit. , Fig. 3
FIG. 3 is a sectional view of the internal reforming unit of FIG. 2 taken along the line AA. In this indirect internal reforming molten carbonate fuel cell, as shown in FIG. 1, a single cell (neither is shown) in which an anode and a cathode are arranged with an electrolyte sandwiched is provided via a separator (not shown). A stack 2 formed by stacking a plurality of internal reforming units 1 filled with a reforming catalyst every several cells (for example, 5 cells), and springs through upper and lower tightening plates 3a and 3b. 4a and 4b and nuts 5a and 5b. A stainless steel manifold (not shown) is attached to each side surface of the stack 2 via a ceramic insulating frame (not shown).

The above-mentioned single cell is an anode made of an alloy of nickel and aluminum with an electrolyte plate in which a eutectic salt of lithium carbonate and potassium carbonate is held in a porous ceramic material containing lithium aluminate as a main component. And a cathode mainly composed of a nickel oxide sintered body. The anode of each unit cell is electrically connected to the cathode of the adjacent unit cell by the separator, and thereby all the unit cells stacked are electrically connected in series.

As shown in FIG. 2, the internal reforming unit 1 and the raw material gas introducing pipe 6 for introducing the raw material gas into the reforming unit and the reforming reaction in the reforming unit are made uniform. A raw material gas partition plate 7 made of stainless steel for controlling the flow of the raw material gas introduced from the raw material gas introduction pipe 6, a reforming catalyst section 8 arranged around the raw material gas partition plate 7, and this reforming catalyst. An internal reforming unit main body including a frame-shaped frame body 10 surrounding the peripheral surface of the portion 8, and sealing plates 11a and 11b that are fastened to both upper and lower surfaces of the internal reforming unit main body.
It consists of and. In addition, on the side surface of the frame body 10,
A plurality of (four in the illustrated example) reformed gas discharge ports 10a for discharging the reformed gas containing hydrogen as a main component to an anode gas return manifold (not shown) are provided.

As shown in FIG. 3, the source gas partition plate 7 has upper and lower sealing plates 11a and 11b on both upper and lower sides of the control wall 7.
Are welded together, and one end is welded to the inner surface of the frame 10. Further, since the source gas partition plate 7 is formed by bending stainless steel into a Σ shape in a side view,
When the upper and lower sealing plates 11a and 11b are tightened to form a stack, the stack is deformed to have the same height as the reforming catalyst section 8. Therefore, even when the height dimension of the reforming catalyst portion is lower than the height dimension of the frame body 10 and the raw material gas partition plate 7, the tightening pressure can be concentrated on the raw material gas partition plate 7 as in the conventional case. Instead, it will be distributed almost evenly. As a result, the internal reforming unit comes into contact with each electrode substantially uniformly, so that stable battery characteristics can be obtained for a long period of time.

The reforming catalyst section 8 is, as shown in FIG.
It has a structure in which a corrugated plate 80 holding a reforming catalyst (for example, a nickel-based catalyst) and a gas separation plate 81 are laminated, and the height dimension of the reforming catalyst portion 8 is the frame body 10 and the raw material. Even when the height of the gas partition plate 7 is higher than the height of the gas partition plate 7, when the upper and lower sealing plates 11a and 11b are attached, the reforming catalyst portion 8 having elasticity has the height of the frame body 10 and the raw material gas partition plate 7. It contracts until the height is almost the same as the height.
Therefore, the tightening pressure is substantially evenly distributed, and the above-mentioned problem does not occur. [Other Matters] In the above embodiment, the source gas partition plate 7 was formed by bending in a Σ shape, but the present invention is not limited to this, and for example, a Z shape, a step shape, or the like. Of course, it is also possible.

(Second Embodiment) FIG. 4 is a schematic plan view of an indirect internal reforming molten carbonate fuel cell using an internal reforming unit according to a second embodiment of the present invention. The constituent parts having the same functions as those of the first embodiment are designated by the same reference numerals and the description thereof will be omitted. On each side surface of this indirect internal reforming molten carbonate fuel cell, an anode gas return manifold 14, an anode gas discharge manifold 15, and a cathode gas supply manifold 16 made of stainless steel are provided via an insulating frame (not shown) made of ceramics. , And a cathode gas exhaust manifold 17 is attached. An anode gas exhaust pipe 18 is connected to the anode gas exhaust manifold 15, a cathode gas supply pipe 19 is connected to the cathode gas supply manifold 16, and a cathode gas exhaust pipe 20 is connected to the cathode gas exhaust manifold 17.

In the internal reforming unit 1, the raw material gas partition plate 7 is divided into an L-shaped raw material gas partition plate 7a and a linear raw material gas partition plate 7b, and the reformed gas discharge port 12 is provided.
Is provided in the frame body 10 and is sufficiently smaller than the reformed gas discharge port 10a of the first embodiment, and the baffle is provided in the anode gas return manifold 14 near the reformed gas discharge port 12. Except that the plate 13 is attached, it has substantially the same configuration as the internal reforming unit 1 of the first embodiment.

According to the second embodiment described above, since the reformed gas discharge port 12 is configured to be sufficiently small, the reforming unit 1
The pressure loss inside is sufficiently large. Therefore, the pressure loss due to the manufacturing accuracy of the reforming unit 1 can be sufficiently ignored, and the raw material gas can be distributed substantially uniformly to each reforming unit 1 installed in the stack 2. Also,
Since the raw material gas flows through the high temperature portion near the cathode gas discharge side, the raw material gas reforming rate can be improved.

Further, since the baffle plate 13 is provided in the vicinity of the reformed gas discharge port 12, the reformed gas is evenly dispersed in the anode gas return manifold 14 to reform the cells in the stack 2. The gas can be distributed substantially evenly.

[0018]

As described above, according to the present invention, since the source gas partition plate is composed of the elastic member, the reforming catalyst portion (that is,
Even if the height dimension of the laminated portion of the corrugated plate and the separation plate is lower than the height dimension of the raw material gas partition plate, the same height as the reforming catalyst portion (that is, the laminated portion of the corrugated plate and the separation plate). Elastically deforms to the desired size. Therefore, when the stack is constructed by tightening the upper and lower sealing plates, the tightening pressure is not concentrated on the source gas partition plate as in the conventional case, but is distributed substantially evenly. As a result, the internal reforming unit comes into contact with each electrode substantially uniformly, which brings about an excellent effect that stable battery characteristics can be obtained for a long period of time.

[Brief description of drawings]

FIG. 1 is a schematic view of an indirect internal reforming molten carbonate fuel cell using an internal reforming unit according to a first embodiment of the present invention.

FIG. 2 is an exploded perspective view of an internal reforming unit according to the first embodiment of the present invention.

3 is a cross-sectional view of the internal reforming unit of FIG. 2 taken along the line AA.

FIG. 4 is a schematic plan view of an indirect internal reforming molten carbonate fuel cell using an internal reforming unit according to a second embodiment of the present invention.

FIG. 5 is an exploded perspective view of a conventional internal reforming unit.

6 is a cross-sectional view taken along line XX of the internal reforming unit of FIG.

[Explanation of symbols]

 1 Internal Reforming Unit 7 Raw Material Gas Partition Plate 8 Reforming Catalyst Section 10 Frame 11a / 11b Sealing Plate

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshihiko Saito 2-18 Keihan Hondori, Moriguchi-shi Sanyo Electric Co., Ltd.

Claims (1)

[Claims] 1. An internal reforming unit main body in which a reforming catalyst is filled in a frame body, and a raw material gas partition plate for controlling a flow direction of the raw material gas is provided in a central portion of the frame body, and the internal reforming unit main body. In an internal reforming unit of an indirect internal reforming molten carbonate fuel cell having upper and lower sealing plates attached to, the source gas partition plate is composed of an elastic member that is elastically deformable in the vertical direction. Indirect internal reforming Characteristic Internal reforming unit of molten carbonate fuel cell.