LU86982A1 - ELECTRODE FOR ELECTROLYSIS CELL AND MONOPOLAR TYPE ELECTROLYSER - Google Patents

Description

1 f Ο 0 0 ~ El GRAND-DUCHÉ DE LUXEMBOURG. BL-4056 / ML

; f PatentN ° '«,,. . ...

—1 Mr. Minister of the 1st ..... September 1987 jriÉâiL · of the Economy and the Middle Classes ~,. KiS Intellectual Property Service

Book title .......... K & Cæ) r

_ BRQ LUXEMBOURG

/ *. S. 57 '^ • Application for Patent of invention? ./ ιύΛΛ ^ ί -------------------------------- ---------------------------------------------------------- ---------- (1) I. Request

The company known as: SOLVAY & CIE, Société Anonyme, 33, rue du Prince, 2) "31 ..... 1 .......... ~ 3. Albert," B - 1050 BRUXELLES, ___ 3 represented .e ..... by .....; ..... E .. ", I." ... FKEYLIKGER ..... & E. MEYERS, Xng. cons. in own. ind., ^) ____________________ ___________________46, rue du cimetière, LUXEMBOURG, agents, ___ removed) this —first ..... September nineteen — one hundred and eighty-seven ------ ”----- ------- (4) at ... 3.00 p.m., at the Ministry of the Economy and the Middle Classes, in Luxembourg: 1. this request for obtaining a patent for an invention concerning: ........................-......................... .........................-........................ ............................—--------------------- ------------------------------------------------- ( 5)

"ELECTRODE FOR ELECTROLYSIS CELL AND TYPE ELECTROLYSER

.......................................... MONOPOLAÏRE "...... .............. 3 ..... 13 _3 Γ I .........................

2. the description in French ........................... ______________ language of the invention in triplicate; 3 .............................! Q .................. ........ drawing boards, in triplicate; 4. the receipt of taxes paid to the Luxembourg Registration Office on the 1st. September. . 8.7 .________; 5. the delegation of power, dated _______— BRUXELLES_______ on J28 August 19 8 7___________________.

6. the successor document (authorization); declares (s) assuming responsibility for this declaration, that the inventor (s) is (are): (6) __________________________________________________________________________________________________________________________________________ claim (s) for the above patent application the priority of one (s) application (s) ) of (7) .......................................... / .. .................................................. ............................ filed in (8) _______________ L ______________________ 1 __............. ...._ ..

on (9) .............................................. .................................................. ..........................! .._______________________________________________________________________ under N ° (10) ............. ................. — ................................ .............................— „____________ L _______________________________________________________________________________________________ on behalf of (11) ........... .........._....................................... .................................................. .................................................. .....................__ ............................ ...........................

elect (elect) domicile for him / her and, if designated, for his / her representative, in Luxembourg _____________________________________________ 4.6, ...... rue ...... du cemetery, ...... LUXEMBOURG __________________________________________________________________________________ (12 ) request) the grant of a patent for the subject described and represented in the aforementioned appendices, with postponement of this grant to _________________________________________ eighteen ....___............. ................................ months. (13)

The representative Éépxsnlxi · ^ —jflL ........................................... .................................................. ................... (14) V Π. Deposit Minutes

The aforementioned patent application has been filed with the Ministry of the Economy and the Middle Classes, IntelleptBclte’ïrLuxembourg Property Service, dated: September 1, 1987

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/ 3 "'....... \ /" J' 3 \ ‘To Pr. The Minister of Finance and the Middle Classes,

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U -x / The head of the service 1 l <intellectual property, U \ A / f q r I) Amn__r _ L- J ïj. EXPLANATIONS RELATING TO THE FORMuîXl * Wï & J> £ f6i: ~ Μ \ e * il va Iîai "" Homanrli »H« »: certificate H'nHrttlinn an hrpvAî nrinrinal à la ΗρτηαηΗ * Ha hn» OAt nrmrinal Mo Hn "-OliniMn > m

BL-4056 / ML

Descriptive memorandum filed in support of a patent application for: ELECTRODE FOR ELECTROLYSIS CELL AND ELECTROLYSER OF THE MONOPOLAR TYPE.

SOLVAY & CIE Société Anonyme 33, rue du Prince Albert

B - 1050 BRUSSELS

- 1 -, D *

Electrode for electrolysis cell r and monopolar electrolyser

Case S 87/10 SOLVAY & Cie (Société Anonyme) The invention aims to improve the electrodes intended for electrolysis cells.

It relates more particularly to an electrode of the type comprising those of a pair of perforated metal plates, 5 placed opposite one another, on either side of several metal bars used for coupling the plates to a Power source.

Known electrodes of this type have been proposed for the production of gases (in particular of chlorine) in electrolysis cells where they are arranged vertically (German patent application DE-A-2821984 (HOOKER CHEMICALS & PLASTICS CORP .; patent European EP-B-0076386 (OLIN CORPORATION)). In these known electrolysis cells, the electrode bars are generally arranged horizontally and it is then necessary to arrange the connection of the bars to the perforated vertical plates of the electrodes, to allow an upward and downward circulation of the electrolyte between the plates.

For this purpose, in the electrolyser proposed in document DE-A-2821984, the thickness of the bars of the electrodes is less than the spacing between their plates and intermediate pieces are arranged at intervals between the bars and the plates. These intermediate pieces are metal profiles which extend vertically over the entire height of the electrode, or metal rings secured to the bars. In these known electrodes, the presence of vertical metal profiles has the disadvantage of vertically partitioning the chamber delimited between the plates of the electrode, which impedes the flow of gas and of the electrolyte between the plates and the uniformity of pressures and concentrations. Furthermore, the construction of metal bars having extra thicknesses, ‘i.

- 2 - local ring finger is expensive; the welding of these annular excess thicknesses to the electrode plates is difficult and punctual and, during the operation of the cell, these welding points are the seat of intense local concentrations of current.

In the electrolyser described in document EP-B-0076386, the thickness of the horizontal bars of the electrodes is also less than the spacing between the plates, and horizontal metal strips pierced with openings connect the bars to the 10 plates. These known electrodes also have the disadvantage of a difficult construction. They lack rigidity and the horizontal metal strips joining the bars to the plates impede the circulation of the gas and the electrolyte in the chamber delimited between the plates of the electrode.

The invention overcomes the disadvantages set out above of known electrodes, by providing a new electrode, which is simple and inexpensive in construction and which is designed to minimize the obstacle to the circulation of gases and electrolytes, when positioned vertically in an electrolysis cell.

Consequently, the invention relates to an electrode for an electrolysis cell, comprising a pair of perforated metal plates, placed opposite one another, on either side of several metal bars which are connected 25 to said plates and serve to couple the electrode to a source of electric current; according to the invention, each metal bar is connected to each plate by means of an individual corrugated metal strip, fixed alternately to the bar and to the plate, so as to form therewith tubular conduits.

In the electrode according to the invention, the perforated metal plates can be, for example, metal sheets pierced with openings, sheets of expanded metal or lattices. The choice of plate material depends on the destination of the elec-35 trode. For example, in the case where the electrode is intended for _ J λ.

- 3 - function as a cathode for the production of hydrogen in a cell for the electrolysis of water or aqueous solutions, the plates can be made of iron, steel, nickel or any other conductive material, active for production electrolytic of hydrogen, such as, for example, those described in patents EP-A-8476, FR-A-2460343, EP-A-113931, EP-A-131978 (SOLVAY & Cie). In the case where the electrode is intended to function as an anode for the generation of chlorine in an electrolysis cell of an aqueous solution of sodium chloride, the plates may advantageously be made of a film-forming conductive material selected from the titanium, tantalum, niobium, zirconium, tungsten and the alloys of these metals, carrying an active conductive coating of a material selected from platinum, ruthenium, rhodium, palladium, osmium, iridium and the alloys and compounds of these metals, in particular their oxides. Electrodes specially adapted for the production of chlorine by electrolysis of aqueous solutions of sodium chloride are those in which the material of the active coating comprises a mixture of ruthenium oxide and titanium dioxide or one of the compounds described in the patents BE-A-769677, ΒΞ-Α-769678, BE-A-769679, BE-A-776709, ΒΞ-Α-785605 (SOLVAY & Cie).

Metal bars have a dual function. On the one hand, they serve as support elements for the metal plates; on the other hand, they serve as electrical conductors to connect the plates of the electrode to a current source.

According to the invention, the metal bars have a thickness less than the spacing between the plates of the electrode and each bar is connected individually to each plate, by means of an intermediate piece which consists of a corrugated strip extending along the entire length of the ba'rreau, along the plate. The strip is oriented parallel to the plate, so as to come into contact alternately with the plate and with the bar and thereby form tubular conduits parallel to the plate and perpendicular to the bar. 35 Metal bars and corrugated strips must J i.

- 4 - be made of metal or alloy which resists the chemical environment for which the electrode is intended. For example, they can be made of iron, steel or nickel in the case of the cathodes defined above, and of titanium in the case of the anodes. Composite bars are advantageously used, comprising a core of a metal or alloy which is a good conductor of electricity (for example copper or aluminum) in an envelope of a resistant metal or alloy, for example made of titanium. These bars are generally obtained by the cofiling technique, well known in metallurgy.

In the electrode according to the invention, the profile of the corrugations of the strips is not critical, but it is nevertheless preferred to use strips profiled in polygonal wave, for example square, rectangular or trapezoidal and bars 15 whose cross section is also polygonal, preferably square or rectangular.

In the electrode according to the invention, the corrugated structure of the strips has the effect of reinforcing the rigidity of the assembly of the plates to the metal bars and it moreover ensures a homogeneous distribution of the electric current in the plates. The presence of tubular conduits formed between the corrugations of the strips facilitates the circulation of gases and electrolytes when the electrode is positioned so as to have its vertical plates and its horizontal bars. To this end, the width of the strips can in fact be limited to the width of the metal bars, which considerably reduces the pressure losses in the circulation of gases and electrolytes in the tubular conduits.

In a particular embodiment of the electrode 30 according to the invention, the plates are pierced with slots oriented transversely relative to the metal bars, and they are provided with lamellae which are oriented parallel to the slots diverging with respect to the · plate, so as to project in front of the slots. This embodiment of the electrode according to the invention ensures optimum distribution of the 1 * - 5 - 1 current on the plates of the electrode and it is well suited to the production of a gas in an electrolysis cell. where it is positioned so that its plates are vertical and its bars horizontal.

In a preferred embodiment of this embodiment of the invention, each plate of the electrode is a metal grid formed by parallel rows of lamellae which diverge from a median plane of the grid, the lamellae each row of lamellae alternating with the lamellae of the contiguous rows and delimiting with them the aforementioned slots. This embodiment of the invention is especially well suited to membrane electrolysis cells, in which the membrane is kept applied to the electrode by the hydrostatic pressure of the electrolyte. In fact, the arrangement of the strips in several alternating rows ensures a uniform distribution of the support zones of the membrane over the entire surface of the grid, which reduces the mechanical stresses on the membrane during electrolysis; all other things being equal, it allows higher current densities and lengthens the life of the membranes.

A specially advantageous configuration for the grid forming the electrode plates is that called "Grigliato Grigliofils” in the advertising brochure "Industrie Longhi - Divisione Fils - Camminamenti, Ponteggi, 25 vie di corsa, gradini, gradinate, piattaforme, paglioli navali, crane "- Stamperia Ed. Comm. - Bergamo (Italy). According to this configuration, each strip of the grid of the electrode has a rectangular profile and is extended, at each end, by a pair of divergent wings which connect it with two lamellae 30 belonging respectively to the two contiguous rows of lamellae; the openings thus have the profile of a flattened hexagon.

In this embodiment of the invention, the dimensions of the lamellae and the wings and the inclination of the lamellae 35 constitute important parameters for the performance of the electrolysis process and for the longevity of the membrane. To this end, it is preferred according to the invention, to use a grid in which the length of the lamellae, measured between two pairs of divergent wings, is between 2 and 4 times their width, and the width of the openings, projected on the median plane of the grid, is between 0.25 and 0.50 times the width of the slats. The angle of inclination of the slats relative to the median plane of the grid can generally be between 15 and 50 degrees, the angles between 25 and 40 10 degrees being particularly suitable. In this embodiment of the invention, it is desirable that the strips and their wings are all identical.

The electrode according to the invention is specially well suited to electrolysers of the monopolar type with vertical electrodes.

The invention therefore also relates to an electrolyser of the monopolar type comprising an alternation of anodes and vertical cathodes in an enclosure, in which the anodes and / or the cathodes are electrodes according to the invention, the bars of which are arranged horizontally and pass through a vertical wall of the enclosure.

The invention relates in particular to an electrolyser of the filter press type comprising a stack of vertical frames which delimit electrolysis chambers containing the electrodes in vertical position and which are crossed by the horizontal bars.

Alternatively, the electrolysis chambers are isolated by ionic separators. In this variant of the invention, the separators are sheets interposed between the successive frames of the stack and made of a material capable of being traversed by an ion current during the operation of the electrolyser. They can be either diaphragms permeable to aqueous electrolytes or membranes with selective permeability.

Examples of diaphragms usable in the electrolyser according to the invention are asbestos diaphragms, such as those described in patent US-A-1855497 (STUART) and in patents

•, i X

- 7 - FR-A-2400569, EP-A-1664 and EP-A-18034 (SOLVAY & Cie) and diaphragms in organic polymers, such as those described in patents FR-A ^ 2170247 (IMPERIAL CHEMICAL INDUSTRIES PLC) and in patents EP-A-7674 and EP-A-37140 (SOLVAY & Cie).

By membranes with selective permeability is meant thin, non-porous membranes comprising an ion-exchange material. The choice of the material constituting the membranes and of the ion-exchange material will depend on the nature of the electrolytes subjected to electrolysis and on the products which one seeks to obtain. As a general rule, the membrane material is chosen from those which are capable of withstanding the thermal and chemical conditions normally prevailing in the electrolyzer during electrolysis, the ion exchange material being chosen from anion exchange materials or cation-exchanging materials, depending on the electrolysis operations for which the electrolyser is intended.

For example, in the case of electrolysers for the electrolysis of aqueous sodium chloride solutions for the production of chlorine, hydrogen and aqueous sodium hydroxide solutions, membranes which are well suited are cationic membranes. of fluoropolymer, preferably perfluorinated, containing cationic functional groups derived from sulfonic acids, carboxylic acids or phosphonic acids or mixtures of such functional groups.

Examples of membranes of this type are those described in patents GB-A-1497748 and GB-A-1497749 (ASAHI KASEI KOGYO

K.K.), GB-A-1518387, GB-A-1522877 and US-A-4126588 (ASAHI GLASS COMPANY LTD) and GB-A-1402920 (DIAMOND SHAMROCK CORP.). Particularly suitable membranes for this application of the cell according to the invention are those known under the names "NAFION" (DD PONT DE NEMOURS & Co) and "FLEMI0N" (ASAHI GLASS COMPANY LTD).

The electrolyser according to the invention finds a particularly advantageous application for the production of chlorine and aqueous solutions of sodium hydroxide by electrolysis of aqueous * * - 8 - solutions of sodium chloride. In the case of electrolysers equipped with NAFION 954 membranes (DU PONT), it is recommended to maintain a weight content of sodium hydroxide of less than 30% in the aqueous solutions present in the cathode chambers, during the first hours following start of the electrolyser. In general, it is desirable that the content of sodium hydroxide is lower the higher the density of the electrolysis current. This operating procedure should preferably be maintained for an operating period of between 2 and 48 hours after starting the electrolyser.

Peculiarities and details of the invention will emerge from the following description of the accompanying drawings which schematize some embodiments of the invention.

FIG. 1 shows a general embodiment of the electrode according to the invention, in cross section with the plates and parallel to the bars;

Figure 2 is a cross section along the planes II-II of Figure 1; FIG. 3 is an axonometric perspective of a detail of an alternative embodiment of the electrode according to the invention;

Figure 4 is a plan view of a particular embodiment of the plates of the electrode according to the invention;

Figures 5 and 6 are cross sections respectively along the planes V-V and VI-VI of the plate shown in Figure 4;

Figures 7 and 8 are views similar to those of Figures 5 and 6, of another embodiment of the electrode plates; FIG. 9 shows in longitudinal vertical section, a particular embodiment of the electrolyzer according to the invention;

FIG. 10 is a vertical cross section along the plane X-X of FIG. 9.

In these figures, the same reference notations designate identical elements.

The electrode shown in FIGS. 1 and 2 comprises two horizontal metal bars 1 and a pair of vertical metal plates 2 arranged on either side of the bars, at an equal distance from them. The plates are pierced with openings 4. Each bar 1 is attached to the two plates 2 by a pair of metal strips 5 oriented parallel to the bars 1 and to the plates 2. The strips 5 are corrugated so as to form substantially trapezoidal undulations, which come into contact alternately with the bar 1 and with the plates 2, to which they are welded. The width of the strips 5 is approximately equal to the height of the horizontal bars 1 (Figure 2). The undulations of the strips 5 thus delimit with the bars 1 and the plates 2, vertical tubular conduits 6 of low height.

When the electrode of FIGS. 1 and 2 is used in the vertical position for the production of a gas in an electrolysis cell, it is positioned so that the bars 1 are horizontal, the plates 2 being oriented vertically. During the electrolysis, the two bars 1 are coupled to the same pole of a direct current source (for example the positive pole if the electrode is an anode), and the strips 5 then serve as an element for electrically coupling the plates 2 to bars 1.

The arrows 7 schematize the circulation of the gas generated on the external face of the plates 2: it passes through the openings 4 of the plates and rises vertically inside the electrode, crossing the tubular conduits 6.

In a variant, shown diagrammatically in FIG. 3, the corrugated strips 5 are pierced with openings 8 in their face 9 intended to be welded to the plate 2.

In the electrode shown in FIGS. 1 and 2, the bars 1, the plates 2 and the strips 5 can be of any metal or metal alloy compatible with the destination of the electrode. Electrodes which can be used as cathodes in cells for the electrolysis of aqueous solutions of sodium chloride are those in which the plates 2 and the strips 5 are made of nickel, the bars 1 being bars of nickel-plated copper. To manufacture these electrodes, the following operations are successively carried out: 5 - nickel deposits are applied to localized surface areas of copper bars 1, for example equidistant annular bands; - The strips 5 are welded to the nickel-plated zones of the bars 1; 10 - the entire assembly thus formed is nickel-plated; - the nickel plates 2 are welded to the strips 5.

An active conductive coating can optionally be applied thereafter to the nickel plates 1, for example of the type 15 of those described in patent application EP-A-131,978 (SOLVAY & Cie).

Figures 4, 5 and 6 show a preferred embodiment of the plates 2 of the electrode. According to this embodiment, the plate 2 is a titanium grid, formed of parallel rows 20 of inclined rectangular strips 16, 16 ', 16 ", ..., 17, 17', ..., 18, 18 ', 18 ", ... The slats are all inclined in the same direction relative to the median plane MM of the grid (Fig. 5 and 6), and the slats in a row (such as the slats 17, 17 ',. ..) alternate with the 25 slats in the contiguous rows (16, 16 ', 16 ", ... and 18, 18', 18" ...). Each slat (for example 17) is extended to its ends, by two pairs of divergent wings 19 which connect it respectively to four strips of the two rows which are contiguous to it (16 and 18; 16 'and 18'). The strips 16, 16 ', 30 16 ", ... , 17, 17 ', ..., 18, 18', 18 ", ... and their wings 19 define openings 20 having the profile of a flattened hexagon. Such a grid can generally be obtained by stamping a metal plate, for example titanium, nickel or iron.

35 The grid 2 of FIGS. 4 to 6 is preferably assembled "* Λ - 11 - to the bars 1, so that the major axis of the strips 16, 17, 18 ... and of the openings 20 is directed perpendicular to the bars 1. Thus, when the electrode is positioned in an electrolysis cell so that the bars 1 are horizontal-5 and the grids 2 vertical, the major axis of the strips 16, 17, 18 ... and of the openings 20 is directed vertically.

In an alternative embodiment, shown in Figures 7 and 8, the grid 2 is provided, around its periphery, with a metal wire 11 of circular cross section, the diameter of which is approximately equal to the thickness of the grid. The peripheral wire 11 eliminates the risk that roughness of the grid 2, such as those designated by the reference notation 12 in Figure 4, deteriorate a membrane which would come into contact with the grid.

The electrolyser according to the invention, shown in FIGS. 9 and 10, is of the type described in French patent application 86.10143 filed on July 9, 1986 (SOLVAY & Cie). It is formed by a stack of alternately anodic 21 and cathodic 22 vertical frames, between two rigid end flanges 20 and 23, on a base 25. Selectively permeable membranes 30 are interposed between the frames 21 and 22 to delimit alternately anode 26 and cathode 27 electrolysis chambers, containing anodes 28 and cathodes 29 respectively.

The anode 21 and cathode 22 frames are made of an elastomeric material, for example a copolymer derived from ethylene and propylene such as those designated ΞΡΜ and EPDM.

Each anode 28 is formed of a pair of perforated vertical plates 2 made of titanium, arranged opposite one another inside an anode frame 21.

Similarly, the cathodes are each formed of a pair of perforated vertical plates 31 made of nickel or iron, arranged opposite one another inside a cathode frame 22. The plates 31 pass tightly through a vertical upright of the frame 22, to be connected together to the negative terminal of a direct current source, not shown. It is advantageous to use nickel plates carrying an active conductive coating obtained by the process described in Example 4 of patent application EP-A-131 978 5 (SOLVAY & Cie), in which the water-soluble compound of molybdenum is the ammonium paramolybdate.

The anodes 28 are of the type described above with reference to FIGS. 1 and 2. For this purpose they comprise several horizontal bars such as that designated by the reference notation 1, interposed between the pair of perforated metal plates 2 to which they are fixed by a pair of corrugated strips 5. The plates 2 are made of titanium and have a coating formed of a mixture of ruthenium oxide and titanium oxide on their face oriented towards the membrane 30. The bars 15 1 are cofiles of a copper core in an annular titanium sleeve and the strips 5 are made of titanium and are welded alternately to the plates 2 and 3 and to the bars 1. The bars 1 pass tightly through a vertical upright 10 of the anode frame 21 , to be connected together to the positive terminal 20 of the current source.

The frames 21 and 22 and the membranes 30 are pierced with four marginal openings 36, 37, 38 and 39 which, aligned in the electrolyser, respectively form four separate horizontal collectors which open respectively in four corresponding openings made through the flange 23 These collectors serve to admit the electrolytes to be electrolyzed into the electrolysis chambers 26 and 27 and to evacuate the products of electrolysis. For this purpose, in the anode frames 21, the marginal openings 36 and 38 are in communication with the anode chambers 26, via conduits 34 and 35 · The cathode frames 22 have corresponding conduits for placing the marginal openings 37 and 39 in communication with the cathode chambers 27.

In the electrolyser shown in FIGS. 9 and 10, the anodes 28 are preferably shaped like that described above, I j - 13 - above, with reference to FIGS. 7 and 8. During the operation of the electrolyser, the pressure is adjusted hydrostatic in the electrolysis chambers 26 and 27 so that the membranes 30 are pushed back against the plates 2 of the anodes 28.

Claims (10)

1. Electrode for electrolysis cell, comprising a pair of perforated metal plates (2), arranged opposite one another, on either side of several metal bars (1) which are connected to said plates and used to couple the electrode to a source of electric current, characterized in that each metal bar (1) is connected to each plate (2) by means of an individual corrugated metal strip (5), alternately attached to the bar and to the plate so as to form tubular conduits (6) therewith. 2. Electrode according to claim 1, characterized in that the plates (2) are pierced with slots (20) oriented transversely relative to the metal bars and are provided with strips (16, 17, 18 ...) which are oriented parallel to the slots and which diverge from the plate, so as to protrude opposite the slots. 3. Electrode according to claim 2, characterized in that each plate (2) is a metal grid formed by 20 parallel rows of lamellae (16, 17, 18, ...) which diverge from a median plane (MM) of the grid, the slats of each row of slats (17, 17 '...) alternating with the slats of the contiguous rows (16, 16', 16 ”, ·., 18, 18 ', 18" , ...) and delimiting with them the aforementioned slots 25 (20). 4. Electrode according to claim 3, characterized in that each lamella of the grid has a rectangular profile and is extended at each end by a pair of divergent wings (19) which connect it to two lamellae belonging to 'respect 30 two contiguous rows of slats. 5. Electrode according to any one of claims 1 to 4, characterized in that the strip (5) is profiled in a rectangular wave and is pierced with openings (8) on its sections (9) which ,, are in contact with the plate (2). - 15 - 6. Electrode according to any one of claims 1 to 5, characterized in that the bars (1) have a rectangular transverse profile. 7. Monopolar type electrolyser comprising an alternation of vertical anodes (28) and cathodes (29) in an enclosure, characterized in that the anodes and / or the cathodes are electrodes according to any one of claims 1 to 6, whose bars (1) are arranged horizontally and pass through a vertical wall (10) of the enclosure. 8. Ele.ctrolyseur according to claim 7, characterized in that it is of the filter press type and comprises a stack of vertical frames (22, 23) which delimit electrolysis chambers (26, 27) containing the electrodes and which are crossed in a sealed manner by the bars (1). 9. An electrolyser according to claim 8, characterized in that the electrolysis chambers (26, 27) are isolated by ionic separators (30). 10. The electrolyser according to claim 8, for the electrolysis of aqueous solutions of sodium chloride. "