JP2761108B2 - Steam electrolysis cell - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steam electrolysis cell for electrolyzing steam into hydrogen and oxygen by a thin-film solid electrolyte ceramic plate.

[0002]

2. Description of the Related Art A conventional steam electrolysis cell will be described with reference to FIG. 8. Reference numeral 11 denotes a thin-film solid electrolyte ceramic plate such as yttria-stabilized zirconium, 12 denotes an anode such as lanthanum strontium manganese oxide or nickel,
Is a cathode made of a nickel YSZ cermet or a nickel, etc., and a thin film solid electrolyte ceramic plate 11 is fired into a cylindrical shape, and an anode 12 and a cathode 13 are fixed to the inner and outer surfaces thereof.
While constituting the unit cylindrical body, the unit constituent bodies are overlapped, and the anodes 12 and the cathodes 13 fixed to the inner and outer surfaces of the upper and lower unit cylindrical bodies are connected alternately (for example, from inside to outside).

[0003]

The capacity (electrolysis amount) of the steam electrolysis cell using the solid electrolyte ceramics is determined by the area of the thin film solid electrolyte ceramic plate 11 sandwiched between the anode 12 and the cathode 13 fixed to the inner and outer surfaces. Since it is proportional, it is necessary to increase the diameter or height of the unit cylinder in order to increase the capacity of the steam electrolysis cell.

In order to increase the electrolysis efficiency of the steam electrolysis cell, it is necessary to reduce the film thickness of the thin film solid electrolyte ceramic plate 11 to reduce the volume per volume of the steam electrolysis cell. Electrolyte ceramic plate 1
The film thickness of No. 1 cannot be reduced so much from the viewpoint of strength, and there is a problem that the volume per volume of the steam electrolysis cell cannot be reduced.

The present invention has been made in view of the above problems, and has as its object to provide a steam electrolysis cell capable of greatly reducing the volume per volume.

[0006]

In order to achieve the above object, a steam electrolysis cell according to the present invention has electrodes fixed to both surfaces of a plate-shaped thin-film solid electrolyte ceramic plate, and a plurality of the ceramic plates are provided. The ceramics box is placed at intervals and the outer periphery of each ceramics plate is airtightly attached to the inner peripheral surface of the ceramics box, and a plurality of voids are formed between the ceramics plates to form the same space. The electrodes in the gaps are connected by good conductors so as to have the same polarity, and the electrodes in the adjacent gaps are set to have different polarities.

[0007]

The steam electrolysis cell of the present invention is constructed as described above, and applies a voltage to both ends of the electrodes attached to both sides of a flat-plate thin-film solid electrolyte ceramics plate and connected in a series, High-temperature steam flows into the cathode-side gap, and carrier gas flows into the anode-side gap. The steam in the cathode-side gap is electrolyzed. Oxygen is transmitted through the flat-type thin-film solid electrolyte ceramic plate, and electrons are emitted from the anode surface. release and, as the O ₂ gas is taken out into the steam electrolysis cell outside the Kiyariyagasu.

[0008]

1 to 5 show a steam electrolysis cell according to the present invention.
1 is a flat-plate thin-film solid electrolyte ceramic plate. In FIG. 2 showing the details of the ceramic plate 1, reference numeral 1 denotes a thin film solid electrolyte ceramic plate made of yttria-stabilized zirconium or the like, 12 an anode made of lanthanum strontium manganese oxide or nickel, 13 a nickel YSZ cermet or nickel or the like. The anode 12 and the cathode 13 are fixed to both surfaces of a flat-plate thin-film solid electrolyte ceramic plate 1. The anode 12 and the cathode 13 cover the flat ceramic plate 1 from an end to a certain height and cover the flat ceramic plate 1.
The anode 12 and the cathode 13 supplement the strength of the flat ceramic plate 1 even if the flat ceramic plate 1 is considerably thin.

1 and FIGS. 3 to 5 show upper and lower side plates of a ceramic box, and the upper and lower side plates 2 are made of airtight insulating ceramics. And, on the inner surface of the upper and lower side plates 2, FIG.
As shown in FIG. 2, an airtight conductive ceramics interconnector 22 made of lanthanum chromium oxide or the like is attached, and the space between the upper and lower side plates 2 and the interconnector 22 is sealed.

A flat-plate thin-film solid electrolyte ceramic plate 1 and upper and lower side plates 2 of a ceramic box are assembled as shown in FIG. One end of each of the anode 12 and the cathode 13 of the flat ceramics plate 1 is connected to an interconnector 22.
Connected through. The space between the interconnector 22 and the anode 12 and the cathode 13 is sealed. Reference numerals 3 in FIGS. 1 and 5 denote left and right side plates of the above-mentioned ceramic box. The left and right side plates 3 are also made of airtight insulating ceramics, similarly to the side plate 2. The upper, lower, left and right side plates 2 and 3 of the ceramic box and the flat ceramic plates 1 form a plurality of voids in the ceramic box. As shown in FIG. 1, the anode-side gaps a surrounded by the anodes 12 and the cathode-side gaps b surrounded by the cathodes 13 are alternately arranged in the ceramic box.

FIGS. 4 and 5 show the end of a ceramic box for supplying and discharging water vapor, carrier gas (gas for carrying separated O ₂ , for example, air and nitrogen gas), separated hydrogen and residual water vapor. Side view. The ends of the upper and lower side plates 2 of the ceramic box are bulged in the vertical direction to form an airtight insulating ceramic small end plate 5, and the end of the small end plate 5 is fixed to the front and rear side plates 4 in a hermetically sealed state, and the header is fixed. Is formed. In this embodiment, all of the anode-side gaps a are open to the same end header, and all of the cathode-side gaps b are open to the opposite header.

Next, the operation of the steam electrolysis cell shown in FIGS. 1 to 5 will be specifically described. Attached to both sides of a flat-plate thin-film solid electrolyte ceramics plate, a voltage is applied to the electrodes at both ends of the steam electrolysis cell, while a steam is caused to flow through the cathode side gap b, and the whole is heated to a high temperature (for example, 700 ° C. to 1000 ° C.).
When heated and maintained in the above-mentioned condition, water vapor is separated by the flat-plate-type thin-film solid electrolyte ceramics plate 1 and oxygen is taken out from the anode side gap a. On the other hand, the hydrogen separated from oxygen remains in the cathode-side gap b and is extracted therefrom.

FIG. 6 shows an entire electrolytic cell unit having the above-mentioned header. 61 and 62 are power supply cables, each of which is connected to electrodes at both ends in the electrolytic cell. 63a is a steam inlet tube, 64a is a carrier gas inlet tube, 63b is a hydrogen and residual steam outlet tube, 64b
Is an outlet pipe for O ₂ and carrier gas. FIG. 7 shows a configuration example of a steam electrolysis cell incorporating three electrolysis cell units 71. Each unit is heated by a heater 72. 73 is a heat insulating material, and 74 is a casing.

[0014]

As described above, the steam electrolysis cell of the present invention applies a voltage to both ends of an electrode connected in a series in a state mounted on both sides of a flat-plate thin-film solid electrolyte ceramics plate as described above, and a cathode-side gap is formed. High-temperature steam flows through the space, and a carrier gas flows through the anode-side voids to electrolyze the steam in the cathode-side voids.
Oxygen is transmitted through a flat-plate thin-film solid electrolyte ceramic plate to release electrons on the anode surface, and is extracted as O ₂ gas out of the steam electrolysis cell using a carrier gas. , The volume per volume of the steam electrolysis cell can be greatly reduced.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional side view showing one embodiment of a steam electrolysis cell according to the present invention.

FIG. 2 is a perspective view showing a flat-plate thin-film solid electrolyte ceramic plate.

FIG. 3 is a perspective view showing a side plate and an interconnector of a ceramic box.

FIG. 4 is a longitudinal sectional side view showing a header portion at an end of a ceramic box.

FIG. 5 is a perspective view thereof.

FIG. 6 is a perspective view showing an electrolytic cell unit.

FIG. 7 is a longitudinal sectional side view showing an example of assembling a plurality of electrolytic cell units.

FIG. 8 is a vertical sectional side view showing a conventional steam electrolysis cell.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 Flat-plate thin-film solid electrolyte ceramic plate 2 Upper and lower plates of ceramic box 3 Left and right plates of ceramic box 4 Front and rear plates of ceramic box 5 Small end plate of ceramic box 12 Anode 13 Cathode 22 Good conductor a Anode-side gap b Cathode-side gap

Claims (1)

(57) [Claims] An electrode is fixed on both sides of a flat-plate thin-film solid electrolyte ceramic plate, a plurality of the ceramic plates are arranged in a ceramic box at intervals, and an outer peripheral portion of each ceramic plate is formed. A plurality of air gaps are formed between the ceramics plates so that the electrodes in the same air gap have the same polarity and the electrodes in the adjacent air gaps have different polarities. A steam electrolysis cell characterized by being connected by a good conductor so that