WO2012003969A1

WO2012003969A1 - Electrode for electrolysis cells

Info

Publication number: WO2012003969A1
Application number: PCT/EP2011/003344
Authority: WO
Inventors: Karl-Heinz Dulle; Dirk Hoormann; Frank Funck; Philipp Hofmann; Stefan Oelmann; Carsten Schmitt; Peter Woltering
Original assignee: Thyssenkrupp Uhde Gmbh.
Priority date: 2010-07-06
Filing date: 2011-07-06
Publication date: 2012-01-12
Also published as: DE102010026310A1

Abstract

The invention relates to an electrode of an electrolysis cell for electrochemical processes, comprising a main body having a three-dimensional shape, wherein the main body comprises electrically conductive spacer means, the spacer means having a spring-like design.

Description

Electrode for electrolysis cells

The invention relates to an electrode and a method for gas-generating electro-chemical processes in an electrolyzer, wherein the electrode in the

installed state of an ion exchange membrane is arranged in parallel opposite, comprising a main body, which is three-dimensionally shaped.

In processes for gas-generating electro-chemical processes, it is known from the prior art that the anode-cathode distance has a considerable influence on the electrolysis voltage. For this reason, it is attempted to keep the distance between the electrodes small.

For example, in chlor-alkali single element electrolysis cells, the electrolysis voltage is reduced by the closest possible arrangement of the components provided therein consisting of ion exchange membrane, anode and cathode. These are various electrolysis cells with flexible elements as

Devices for reducing the distance between the electrodes have been proposed. In addition, flexible elements of woven fabrics, nonwovens, mesh or mesh of thin metal wires which are laid on the electrodes have been developed. Such materials and embodiments that are suitable for this purpose, for example, in WO2009 / 007366 A2, EP1434294B1, the

DE3028970C3 and DE 69322527T2. With these current-conducting ribs, a plurality of uniformly distributed over the electrode surface contacts to be created. The disadvantage is that in industrial processes electrode surfaces in the order of at least 0.5 m ² must be used. The problem with this is that after assembly of the electrolytic cell, a uniform contact pressure across the electrode surface must be ensured, which is very difficult to achieve with this cell size. This happens

Current concentrations at points with greater contact pressure. this leads to

Polarization phenomena and the associated deactivation of the membrane and the catalytic electrodes.

In addition, such mattresses or ribbed structures have the disadvantage that they condense during assembly, which is the gas removal during the electrolysis

CONFIRMATION COPY negatively influenced. Another problem arises in case of operational incidents. If a reverse pressure arises, which can lead to a permanent deformation of the cathode, the anode to cathode distance increases and the

Element voltage increases. When shutdown, it is also common that, for example, in the chlor-alkali electrolysis, the anode-side generated chlorine diffused and the activated cathode attacks, causing it is damaged and turn the

ion exchange membrane can perforate.

A further development disclosed in JP-A-57-108278 by a plurality of flat strip-shaped leaf spring elements as electrical connection between a

Electrode chamber partition and an electrode are provided. such

Electrodes are better suited to deformation by force application than electrodes using thin wire elements or similar elements. However, all such flat strip-shaped leaf spring elements extend from a flexible support member at an angle in the same direction.

Upon application of a force from the side of an electrode surface, however, the flat strip-shaped leaf spring elements may be deformed and misaligned, which may result in damage to the ion exchange membrane.

In DE60302610T2 an electrolyzer is disclosed in which an electrode is in contact with a plurality of comb-like flat strip-shaped leaf spring elements extending at an angle from a flat leaf spring shape of a holding member disposed on an electrode chamber partition wall disposed in an electrode chamber, wherein each pair of comb-like arranged flat plate spring members is arranged such that adjacent flat strip-shaped leaf spring members extend in mutually opposite directions.

In DE 102006046807 A1 discloses an electrolytic cell is disclosed in which an electrode is curved in the direction of the opposite electrode. As a result, a flat pressing of the membrane between the two electrodes is achieved. The curvature is ideally achieved by a plurality of springs, which are stretched between the electrode and the rear wall of the electrolysis cell. The springs are not part of the electrode. A disadvantage of this technology is still that the electrode, which is in contact with the contact spring elements, slipping of the individual elements during assembly and thus a uniform contact surface or damage to the electrode can not be excluded. The object of the present invention is therefore an electrode for

To provide that no longer has the problems indicated.

In particular, the electrode should be easily replaceable and have high stability.

The object of the present invention is achieved by the use of an electrode of an electrolytic cell for electro-chemical processes, comprising a main body, which is three-dimensionally shaped, wherein the base body has electrically conductive, distance-holding means, wherein the distance-holding Means are designed spring-like.

In this case, the electrode according to the invention is arranged in the installed state in an electrolysis cell of an ion exchange membrane parallel opposite. The distance-holding means are at the

Ion exchange membrane opposite side of the base body arranged.

The spacing-holding means, which has the body, are in firm connection with this. Ie. they are part of the electrode itself. Advantageously, the distance-maintaining means are generated by, for example, in the production of the electrode, the distance-maintaining means are designed by bending the electrode at the appropriate points feathery. Alternatively, the spacer-holding means may be attached to the electrode by common methods such as screwing, welding or gluing so as to become a part of the electrode itself.

In this case, the spring rate can be adjusted so that even in the case of a caused by an operational incident reverse pressure in the

Electrolysis cell, the cathode is not deformed. The cross sections of the spring-like means are variably selectable. In addition, it is up to those skilled in the art to select a material for the spacing means which provides electrically conductive properties. Advantageously, a material is used which is the same or similar to that of the electrode body. In an advantageous embodiment of the invention are as distance-holding means helical, spiral, rod-shaped stretched and / or kinked

Designs provided.

In a further embodiment of the invention, the distance-maintaining means over arbitrarily shaped transition areas in solid connection with the

Body.

Preferably, the base body, in the manner of a flat C-profile, of a first flat flat part, which runs parallel to the membrane in the installed state and one or more flank parts, which in the installed state at an angle of at least 10 degrees of angle Membrane are inclined away, and one or more arbitrarily shaped transition regions are arranged between the flat belly part and the one or more other flank parts.

Advantageously, the main body of the electrode has continuous openings. In this case, the openings are preferably arranged on the flat belly part of the electrode base body.

Furthermore, the invention comprises an electrolysis process for the production of halogen gases from aqueous alkali halide solutions, wherein planar electrodes are used according to one of the preceding claims.

In a further embodiment of the method according to the invention electrolyzers are used in the single cell construction, wherein the Einzelzellelektrolysezellen, an anode half-shell with an anode, a

Cathode half-shell with a cathode and a arranged between the anode half-shell and cathode half-shell ion exchange membrane comprise.

The invention will be explained in more detail with reference to 2 figures. Show it:

An inventive electrode in an advantageous box-like design

Fig.2 Schematic arrangement of the electrode according to the invention in an electrolyzer, which is shown in cross section.

Fig. 1 shows an electrode 1 in the embodiment of a flat box profile. The bent down flanks 2 and 3 are kept very short in relation to the flat belly part 4, which is designed to be many times wider. Between Flanks 2 and 3 and the belly part 4 are the transition areas 5a and 5b. Advantageously, the electrode 1 has in the flat abdominal region 4 in rows arranged holes (not shown), wherein these rows of holes arranged parallel to each other and the holes are offset diagonally to each other. As a result, the available area of the abdominal part 4 can be used most effectively for the electrolysis. Advantageously, there is another row of holes in the transition regions 5a or 5b,

or are even more additional rows of holes in the flanks 2 and 3 itself provided. An essential advantage of this embodiment is that the

Belly part 4 is arranged in the installed state plane parallel to the membrane, in which the electrochemical reaction can proceed. The membrane is supplied via the holes with brine or brine.

Furthermore, the electrode 1 has two permanently connected to this spring elements 6a and 6b. In this case, the transition regions 7a and 7b between the flank parts 2 and 3 of the electrode and the spring elements 6a, 6b can be configured as desired.

FIG. 2 shows a schematic arrangement of the electrode 1 according to the invention, comprising the spring elements 6a and 6b in an electrolyzer. By way of example, the electrode according to the invention is used as the cathode. The electrode is placed in the cathode half-shell 8. In the assembled state, the spring elements 6a and 6b made of an electrically conductive material touch the

Cathode half shell, so that the electrical contact is ensured. The belly part 4 of the electrode 1 is arranged plane-parallel to the membrane 9. On the

opposite side of the membrane 9 is the anodic electrode 10, which is arranged on a web system and is located in an anode half shell 11. Such individual elements 12 are stacked in an electrolyzer stapeiförmig side by side. About contact elements (not shown) is made between the individual internals of the electrical contact. Separate holding elements, which press the electrode 1 against the membrane 9 and at the same time establish electrical contact with the cathode half-shell 8, are rendered superfluous by the design of the electrode 1 according to the invention.

Advantages resulting from the invention: no slippage of individual elements during assembly possible because the electrode is made of a single component.

simply by setting the electrode in the electrode half shell, the electrical contact is ensured. simply by setting the electrode according to the invention in the electrode half shell a simple maintenance and interchangeability is gewährleitstet.

By adjusting the spring hardness, permanent reshaping of the electrode can be avoided.

uniform contact pressure over the entire electrode surface is achieved the electrode design has a high stability

a minimized flow resistance can be ensured.

[0031] List of Reference Numerals

1 cathodic electrode

2 flank

3 flank

4 belly part

5a, b Transition areas between stream and flank parts

6a, b spring elements

7 transition areas between flank parts and spring elements

8 cathode half shell

9 membrane

10 Anodic electrode

11 anode half shell

12 single element

Claims

claims

1. Electrode of an electrolytic cell for electrochemical processes, comprising a main body, which is shaped in three dimensions,

characterized in that

the base body has electrically conductive, distance-holding means, wherein the distance-holding means are designed spring-like.

2. An electrode according to claim 1, characterized in that the distance-holding means consist of an electrically conductive material which is the same or similar to that of the base body.

3. Electrode according to one of claims 1 or 2, characterized in that as a spring-like configuration of the distance-holding means

helical, spiral, rod-shaped elongated and / or kinked designs are provided.

4. An electrode according to any one of claims 1 to 3, characterized in that the distance-holding means are about arbitrarily shaped transition regions in solid connection with the body.

5. Electrode according to one of claims 1 to 4, characterized in that the base body in the manner of a flat box profile consists of a first flat belly part and one or more flank parts, and between the flat belly part and the one or more flank parts or several arbitrarily shaped transition regions are arranged.

6. Electrode according to one of claims 1 to 5, characterized in that the main body of the electrode has continuous openings.

7. electrolysis process for the production of halogen gases from aqueous

Alkali halide solutions, characterized in that planar electrodes are used according to one of the preceding claims.

8. electrolysis process according to claim 7, characterized in that for the production of halogen gases electrolyzers are used in single-cell construction, wherein the Einzelzellelektrolysezellen, a

Anode half-shell with an anode, a cathode half-shell with a cathode and an ion exchange membrane arranged between anode half-shell and cathode half-shell.