DE2245926A1 - HORIZONTAL, PLANAR, BIPOLAR DIAPHRAGM CELLS - Google Patents

Description

PATENT LAWYERS
DR. W. KINZEBACH - DIPL.-ING. O. HELLEBRAND 2 2 4 5926

8 Mündien80 Sept. 19, 1972 Walpurgisstrasse 6 Telephone: 0811/47050 34 Telegrams: Hekipat (Munich)

CASE: 267044

ORONZIO DE NORA IMPIANTI EiETTROCHIMICI S.p.Ä. Milan, Italy.

Horizontal, planar, bipolar, diaphragm cells

The invention "relates to horizontal diaphragm electrolytic cells, as used, for example, in the electrolysis of aqueous solutions of alkali metal halides. As a special embodiment, the invention is used for the application "to the electrolysis of sodium chloride for manufacture of chlorine, hydrogen and sodium hydroxide, but it is clear that the device described here and the procedure described here for many other electrolysis processes, like the electrolysis of aqueous solutions of other alkali metal halides, for the production of chlorates »and for the electrolysis of other solutions can be used to produce electrolysis products.

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The invention uses dimensionally stable anodes which have a so-called valve metal base, for example made of titanium or tantalum or alloys thereof, the opposite the cell conditions is stable and with an electrically conductive electrocatalytic coating of a or several oxides of metals of the platinum group with other protective oxides, such as titanium oxides, or with a coating of metals of the platinum group in metallic form, which does not passivate over long periods of time.

As will be described in more detail later, these are dimensionally stable Anodes take the shape of sieves, meshes, rods or have other open shapes that are about $ 30-60, preferably $ 50 up to 53 # / free spaces or gaps, based on the total free-standing Surface of the anode sieves, so that chlorine or other gas bubbles that are formed on the anodes »easily go through the horizontally attached anodes and escape at the top of the anode screens, so that gas shielding the anodes and the gas outflow from the horizontally mounted anodes are not a problem and the bubble effect is negligible will. These dimensionally stable metal anodes can be used for several years without being replaced, but where Graphite anodes, as used in the past, replaced about every 6 to 8 months due to graphite consumption must be (with complete dismantling of the cell) and which are subject to gas shielding in a horizontal arrangement, since the number of gaps (holes through the anode) in graphite anodes must be very small in order to weaken them too much to avoid the graphite anodes,

The object of the present invention is therefore to create a horizontal diaphragm electrolysis cell, the plane Electrodes used in a horizontal arrangement »with the anodes having more than 30-60 # gaps, causing leakage of the anode gases and a gas purification

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the anodes is avoided. This also includes creating bipolar Diaphragm electrolysis cells with horizontal, planar electrodes, used for open meshed metal anodes will. The aim is to create a diaphragm electrolytic cell consisting of a series of horizontal frame members that are stacked on top of one another, with essentially planar anodes, cathodes and diaphragms that are essentially are fastened in a horizontal arrangement in the horizontal frame members, thereby facilitating assembly and disassembly the cell is relieved. According to the invention, a stacked, bipolar diaphragm electrolysis cell is to be created, . which takes up little floor space in relation to its capacity. This includes creating a stacked, horizontal one Diaphragm cell in which the frame members forming the stack alternating from a conductive metal (such as steel or another ferrous metal) and a non-conductive, electrically insulating, chemically resistant material, such as glass fiber reinforced polyester, polyvinyl chloride or the like, exist. Finally, it is also part of the object of the invention to create a diaphragm electrolysis cell, consisting of a series of substantially horizontal units stacked one on top of the other with interposed electrical insulating gaskets, these units consist of a horizontal frame surrounding a flat sheet metal, which carries the cathode screen on its upper side and the anode structure on its lower side.

The novel horizontal bipolar diaphragm electrolytic cell of the present invention is composed of a cathode compartment at the bottom of the cell, a multitude of stacked bipolar units and an anode compartment at the top End of the cell with electrically insulating seals located between each of the stacked frames, , each such unit consisting of an anode compartment, the is set up so that there is an anolyte liquid in its

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lower part contains and a cathode compartment that is furnished is that it contains a catholyte liquid on its upper side, it is a cathode compartment, which is closed at the top by a metal sieve (e.g. a sieve made of iron mesh or iron rods, etc.), the represents the cathode on which the cathodic diaphragm is located is located. An anode compartment is arranged to have a horizontal, substantially planar, permanent vent metal anode ("valve metal anode"), which has 30 - 60% gaps and an electrically conductive electrocatalytic Carries coating on each anode and is in electrical communication with the cathode of the cell above; an anode compartment has means for introducing anolyte liquid into each of the anode compartments and anolyte gas from the compartments to remove, devices for removing catholyte liquid and catholyte gas from the cathode compartments and devices, to pass electrical current through each of the cell units to that fed into the anode compartments Electrolyze anolyte liquid.

Turning now to the drawings illustrating preferred embodiments of the present invention:

Figure 1 is a vertical section through a stacked, bipolar electrolytic cell, substantially on top of the Line 1-1 of Figure 2, which illustrates the construction and operation of the cells of the invention;

Figures 1a and 1b give details of another form of bipolar connection between the cathodes and Anodes of a bipolar cell again;

Figure 2 is a top plan view, partially in section, of the cell shown in Figure 1;

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Figure 3 is a section of the cathodic gas drainage system, substantially along line 3-3 of Figure 2;

Figure 4 is a section of the catholyte drainage system; essentially along the line 4-4 of Figure 2?

Figure 5 is a side view, partly in section, another embodiment of a stacked, bipolar, electrolytic cell according to the invention?

Figure 6 is a view, in partial section, taken generally along line 6-6 of Figure 5 "

Figure 7 is a plan view through one of the insulating polyester frame from one of the anode sections «., the embodiment of Figure 5, substantially along the Line 7-7 of Figure 5; ■

Figure 8 is a plan view through one of the steel frames of one of the cathode sections, essentially along the line 8-8 of Figure 5 »

Figure 9 illustrates in enlarged detail the right and left sides of several of the cell sections of the embodiment of Figure 5;

Figure 9a shows details, similar to Figure 9, which graphically depict the flow of gases and liquids in the cell FIG. 5 sseigen;

Figure 10 is a partial section through the electrolyzer of Figure 5ϊ

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Figures 11, 12, 13 and 14 are detailed representations of the brine charging and anodic gas discharge devices; FIG. 11 being a vertical section along line 11-11 of FIG. 13; at figure 12 is a horizontal plan view, partly in section, along line 12-12 of FIG. 11; Figure 13 Figure 5 shows an enlarged detail of the brine feed and anodic gas discharge end of each cell of Figures 5 and 7 14 is a sectional view taken along line 14-14 of FIG.

Figure 15 is a sectional view of an alternative form of electrical connection between the anodes and the titanium backplate;

Figure 16 is a sectional view taken along line 16-16 of Figure 15;

Figure 17 is a top plan view of the top plate of the stack of electrifying devices of Figure 5ϊ

Figure 18 is a bottom plan view (looking up) the bottom plate of a stack of the electrolyzer of Figure 5; and

Figures 19 and 20 are enlarged plan views of vcn two open mesh anode designs that fill the gaps show through which the anodic gases escape upwards into the anodic gas space.

Although the cell as a series of stacked bipolar cell units As illustrated and described, it will be understood that individual line units of the type illustrated can be built with only one anode and one cathode and operated as single unipolar cells.

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In the embodiment of the horizontal, planar, bipolar cell illustrated in FIGS. 1 to 4, the Cell consists of a plurality of stacked, bipolar elements in a cell stack A consisting of 50 or more individual cell units same construction, of which only four complete units are shown. Each unit will from a rectangular steel frame A1, A2, A3, A4, A5 etc., formed, the top and bottom flanges F1 and F2, each of which lower flange F2 on the upper flange F1 of the next lower unit, with insulating seals 3? 3 being provided between the units in order to to form a tight connection.

Each frame A1, A2, A3, etc. houses a cathode section in one part of the frame and an anode section in the other part so that when the frames are assembled, As Figure 1 shows, the an ο denäb cut a frame over the cathode section of the next lower frame lies. The construction of the top frame Al and the bottom frame A5 differs slightly from the intermediate frames, as Figure 1 shows. The bottom frame A5 has a right-angled flat steel sheet B, which is from the top of the frame approximately 1/3 away welded into the frame or otherwise in good electrical connection in the frame is attached and forms the bottom plate of the cell stack. The bottom plate B has reinforcing ribs B2, which see extend from side to side of the plate B and rest on insulating supports B3. the frame A5, the base plate B and the reinforcement ribs B2 are welded together to form a unitary structure and the negative busbars (not shown) are connected to the base plate B. Similar floor panels C1, C2 and C3 are for the upper ones Cell units of the cell stack A shown. Although the Cell stack A is described as being essentially horizontal, it will be clear that the cells are 1 or 2 ° from the horizontal

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are inclined to a "better drainage of the catholyte or other fluid from the cell units.

A plurality of angle irons, which serve as support rods B1 for the cathode screen, are welded or otherwise attached to the top of the plate B and onto the same bottom plates C1, C2 and C3 and the cathode screens D1, D2, D3 and D4 are with welded to the upper edges of the frames A2, A3, A4 and A5 and attached to the upper ends of the angle iron supports B1 by welding. The cathode screens D1, D2, D3 and D4 are covered with diaphragms made of asbestos fibers, paper or fabric (not shown). The spaces between the cathode screens D1, D2, etc. ^v and the floor panels B, C1, C2 and C3 and the surrounding walls of the rectangular spaces A2, A3, A4 and A5 form the cathode chambers of the cell stack A.

The anode chambers are located in the lower (approximately) 2/3 of the next higher frames A4, A3, A2 and A1 and are like inverted Box E1, E2, E3, E4 designed. The anode boxes E1, E2, E3 »E4 are lined with a material that is opposite is resistant to cell conditions. The lining G can consist of titanium, tantalum, hard rubber or plastic and protects the side walls and ceilings of the inverted anode boxes against the corrosive effects of brine and anodic gases. The lining G goes to below the floor flange F2 the frame A1, A2, A3 and A4, as shown at G1 and rests on the insulating seals F3, so that the anode chambers are completely isolated from the cathode chambers.

Anode suspensions or feeds H are connected to the base plates C1, C2, C3 and to the top plate A6 of the top frame member A1 in order to connect the anodes I in the anode boxes or chambers E1, E2, E3 and E4 via primary conductor bars 11 (Figure 2). connected to secondary conductor bars 12 which are at right angles to the primary conductor bars 11

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"The secondary conductor bars 12 are connected to the working" surfaces 13 'of the anodes, which may be in the form of screens, meshes, bars or other open shapes with about $ 30 to $ 60 gaps so that the The anode assembly I, 11, 12, 13 consists of a so-called valve metal, such as titanium or tantalum or alloys thereof, and the primary and secondary conductor bars and the work surfaces are preferably welded together The anode supports H can be made of titanium-plated copper or any other electrically conductive material which is suitably insulated or protected from the corrosive conditions of the anode chambers. The working surfaces 13 of the anodes are made of thin metal sheets (approx up to 1.5 mm) of a so-called valve metal, which is located at a spatial distance of about 4 - 10 mm above the cathode sieves Ne anode surfaces with approximately 50% gaps are illustrated in Figures 19 and 20, described below, and are coated with an electrically conductive electrocatalytic coating of one or more oxides of platinum group metals together with other protective oxides such as oxides of titanium or with a coating of Platinum group metals coated in metallic form.

If. Titanium or tantalum is used for the lining & of the anode boxes E1, E2, ~ E3 and E4, these linings can be welded to the preceding cathode base plates 01, C2> C3 and A6 or electrically connected in some other way, the linings & can then serve as back plates for the anode assemblies I through 13, and the anode structures can be electrically connected to the back plates as illustrated in Figures 10 and 15, which will be described in more detail later in connection with these figures.

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The cover plate A6 is welded into the uppermost frame At and equipped with Yer reinforcement ribs A7 and the positive ones Bus bars (not shown) are connected to the cover plate A6. The cells work as bipolar cells with through the Cover plate A6 and through all cells in the stack to the base plate B flowing stream.

Brine is introduced into each anode chamber E1, E2, E3 and E4 from feed lines J through branch lines J1 in the amount necessary to maintain the desired level of solubility and to maintain the flow through the diaphragms, the brine level is increased as the porosity of the diaphragms decreases » as described below. During the electrolysis of sodium chloride brine, chlorine gas flows from each anode chamber through the chlorine discharge lines K into the chlorine collecting pipes K1 in the chlorine recovery system. Any excess brine flowing through the drains K is recovered in trap K2 and returned to resaturation. From the upper end of the cathode chamber, hydrogen escapes through the outlets Ii into the hydrogen manifold L1 and sodium hydroxide flows from the bottom of the cathode chamber through the outlets M1, which are preferably located on the side of the cell opposite _{the Cl 2 and Hp outlets.} The cell is inclined about 1 - 2 ° in the direction of the sodium hydroxide drains M.

The cell stack of FIGS. 1 to 4 is secured by the seals F3 for each of the frames A1 to A5 and by the Weight of the frame and the electrolyte in it in liquid-tight Connection held. However, it can be hammering can be used between each frame member or tie rods similar to tie rods 15 shown in FIG To hold stacks of cells together.

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In the special form of an Mpolar connection between the Cathodes and anodes, as illustrated in Figure 1a, are the anode working surfaces 13 with secondary conductor rails. NEN 12 connected, which are connected to primary conductor rails 11. The primary titanium conductor rails 11 are with Copper brackets H connected, which are covered with an insulating coating H1 made of titanium, rubber or the like and Collars H2 at the upper end of the brackets H press against seals H3 and thus form a liquid-tight connection with the lower part of the cathode base plates 01, "02, 03 etc. The upper end of the anode holder H is screwed with nuts H4, they press against the cathode bottom plates 01, 02, 03 and A6 and create an electrical connection between them the cathode bottom plates and the anodes I.

Figure 1b illustrates a modified form of a bipolar connection between the cathode base plates 01, 02, 03 etc. and the anodes I, the primary titanium conductor rails 11 being connected to the copper brackets H by screws 14, which are covered with a titanium protector 15 and the upper part of the brackets H is beveled and sits tightly in accordingly beveled openings in the cathode bottom plates 01, 02, 03 etc. A threaded screw H5 is used to secure the pull the beveled part of the holder H into the bevel in the cathode base plates 01, 02, etc.

The embodiment of a horizontal, planar, bipolar cell A illustrated in FIGS. 5 to 18 is intended to show a stack of 50 or more individual cell units which are fastened to a steel base plate 1 which carries the negative connection of the electrical circuit and the stack is covered by a steel cover plate 2, to-di: e the positive busbar is connected, the bi- ;;., ^: . polar cell units are located between the base plate 1 and the cover plate 2. .

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Each cell unit consists of a rectangular steel frame 3 surrounding the cathode chamber and an insulating rectangular anode frame member 4 made of glass fiber reinforced polyester or other suitable insulating material, with which the anode chamber is formed. A steel cathode screen 3a is puridewelded at several locations to the upper inner corner of each cathode frame 3 and each cathode screen is arranged to support a diaphragm 10 (shown in dashed lines in Figures 10 and 15) which is a woven film made of asbestos fabric or another suitable diaphragm material or an asbestos fiber diaphragm which is applied to the cathode screens 3a by suction. Intake nozzles 3b (FIG. 10) are provided in the frame 3 for the initial deposition of diaphragm material on the cathode sieves 3a. The lower side of each cathode screen rests on steel ribs 3c welded to the StaKU bottom plate 3d of each cathode frame and tack welded to the cathode screens 3a to support the screens and make a good electrical connection between the cathode screens and the bottom plates of the cathode frame.

On top of each cathode frame 3 is a rubber seal 4a (Figures 10 and 13) and provides for a subdivision and a liquid-tight seal between the steel cathode frame 3 and the. insulating polyester anode frame 4th

The anodes 5 consist of thin sheets (about 0.5 to 1.5 mm) of a so-called valve metal, which under the cell conditions is resistant, like titanium or tantalum or alloys of titanium or tantalum, which is a conductive electrocatalytic Has coating which is a mixture of titanium or tantalum oxides, oxides of a metal of the platinum group or Contains oxides of other metals, or the anode surfaces can

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covered with a platinum group metal in metallized form be. The anodes 5 can be in the form of meshes, sieves,. Rods, or the like and may be on either or both of Sides, the front and the back, the anode with coated the electrically conductive electrocatalytic coating be. The active surfaces of the anodes 5 are located at a distance of about 4 - 10 mm above the cathode sieves 3a and diaphragms and protrude sufficiently "into the anolyte liquid, so that an effective electrolysis of the anolyte liquid is achieved in the electrode gap between the anode surfaces and the cathode sieves 3a.

The anodes 5 are suspended in the anode frame 4 on a titanium (or tantalum) back plate 6, which is on the cathode base plates 3d of the next higher cathode element rests and electrical contact with the back plates 3d by screwing, Welding or the like produces. The titanium back plates 6 · rest on smaller seals 4b ″ on the top of the seals 4d on the polyester frame 4 (Figure 10, right side). The seals 4b provide storage for the back plates 6. The anodes 5 are attached to the back plates 6 by Legs 5a attached to the back plates 6 by welding are, and by integral (or separate) inverses U-shaped legs 5b (Figure .10), which are also attached to the back Plates 6 are welded to make electrical contact with the back plates, so that the electrical current flows into the cell stack, from the. positive terminals 2a (Figure 5) through each cell unit in the stack to the negative Terminals 1a connected to the base plate 1.

Into the anode compartment in the anode frame 4, brine flows from a brine feed line 7 and a series of branches 7a and pours in a multitude of streams onto a balcony 8 _% located near the bottom of each. Anode frame 4 is located and on one side of each anode frame 4

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runs along (see. Figures 9, 9a and 12). Each balcony is 8 finished with a weir (a lip) 8 "b, the one with semicircular . Notches 8c is equipped. Clay the balcony 8 the brine flows through a series of charging holes 8a into the anode chamber 4c. There is enough brine in the cell stack fed to allow the liquid to percolate through the diaphragms 10 at the required flow rate, wherein a constant * static level in the anode chambers 4c above the active surfaces of the anodes 5 is maintained. This is achieved by feeding in a little more brine than the percolation flow rate so that the excess Current at the notches 8c at the upper edge of the weir (the lip) 8b overflows and down to the next lower projecting one Deflection surface 9a flows, which on the side where the brine feed is introduced, at the end of each cathode- frame occupies a space in the cell stack. Alternatively, brine can be installed on each balcony 8 with the help of separate branch lines 7a, from the brine feed line 7 to each of the Balconies 8 lead to be initiated. As in the fiery eight, 9 and 13, the StahTr cathode frames 3 are shorter as the anode frames 4 and the polyester inserts 9 occupy the space between those parts of the anode frames which protrude outwards over the cathode frame. Each insert has a projecting deflector surface 9a, which the downward flowing Brine flow to the next lower balcony 8 in the cell stack distracts. Each balcony will therefore solo at one flow rate charged that is sufficient to exceed a static pressure head to maintain the anodes in the appropriate anode compartment and provide an overflow current that feeds the lower anode compartments. As shown in Figures 5 and 9a, the one overflowing from the lowest balcony leaves via * Schüssige flow the stack through the brine flow line 7c and goes through a trap 7d into a return pipe. A safety glass 7e in the drain line 7c enables the operation »- personnel to monitor the brine flow from the cell stack and

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to control the brine feed rate so that the desired overflow is given.

When the cell is in operation, the brine is in each of the anode frames 4 formed anolyte chamber at the level of the upper level of the notched weirs (or lips) 8b and flows through the Diaphragms 10 and the cathode screens 3a in the catholyte chamber in the lower part of each cathode frame 3. -In the electrolysis of sodium chloride brine for the production of chlorine, sodium hydroxide and hydrogen, chlorine is released at the anodes 5 and goes up through the gaps of the anode meshes in the Chlorine space at the upper end of the anode chambers 4c and flows out the polyester anode frame 4 out through the chlorine outlets 8d (shown in solid lines in FIG. 11 and in dashed lines Lines shown in Figure 13) into the chlorine discharge chamber 11 extending from the top to the bottom of the cell stack A. extends and into the chlorine collection pipe 11a, from where it flows into the chlorine recovery system. ·

Sodium hydroxide and hydrogen are generated at the cathode screens 3a and flow through the holes 3e in the cathode frame 3 into the hydrogen and sodium hydroxide drainage slots 12, which extend from the top to the bottom of the cell stack A and are located on the side, which is opposite the supply line for the brine. In the interconnected slots 12 the hydrogen separates from the sodium hydroxide and flows upwards to the Hp outlet 12a and to the hydrogen recovery system, while the catholyte, consisting of sodium hydroxide (about 11 - ^ 2fo ± g) and exhausted brine through the Flow NaOH outlet 12b into the NaOH recovery system.

For the correct operation of a diaphragm electrolysis device a certain pressure is required in each anode chamber in order to push the anolyte through the diaphragms into the cathode chambers to drive.

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In a stacked, horizontal, planar, bipolar diaphragm cell, As described above, it is not appropriate to generate this pressure with the aid of the normally used single static liquid pressure head in each anolyte chamber, as is done in normal diaphragm cells, since in the cell stack A of FIGS. 1 to 4 or FIGS. 5 to 18 the Elements are at different levels and the number of elements is large. The desired pressure on the anode side however, any element in cell stack A can be maintained in one of two ways:

a) By controlling the outflow of the chlorine gas produced with the aid of a throttle valve (not shown) in the chlorine collection pipe K1 or 11a throttles, while the generated hydrogen leaves the cathode chambers without throttling, so that a pressure generated by chlorine gas, which acts equally on the anolyte of all elements; or

b) by taking the generated hydrogen gas a certain vacuum relative to the chlorine gas in the Sanmelrbhr L1 or 12a sucks in while the chlorine leaves the electrolyzer at about atmospheric pressure, so that the generated Pressure difference across the chlorine drainage holes K or 8d in the same Measures acts on the anolyte of all elements so that the desired pressure difference is maintained. With the help of a these methods can create a positive pressure differential between of each anolyte compartment and its corresponding catholyte compartment will.

Method (b) is preferred because there is a chlorine pressure in the anode chambers, as Tinter (a) described, would cause a slight increase in the chlorine solubility in the anolyte, which is a corresponding Chlorate increase in the caustic solution produced would result. The numerical value of the pressure difference generated according to methods (a) or (b) is dictated by the operating parameters, namely

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ft

by the achievable NaOH percentage and the assigned Chlorate content of the caustic solution produced. This pressure difference depends on the current density, the type of diaphragm and the age of the Diphragma, in other words, in the course of a lifetime of the diaphragms, the pressure difference generated from time to time by the methods (a) or (b) explained above be set as. with every other type of diaphragm chlorine cell, since the diaphragms become less permeable the longer you use them.

The caustic solution leaves the cathode chambers through the boreholes 3e into the rectangular steel frame 3 and leaves the electrolysis facing through the ground; the hydrogen formed flows through the same boreholes as each cathode chamber connect with the chamber 12 of the corresponding rectangular steel frame, and flows upwards through the chamber 1? all steel and polyester frames formed common space and leaves the electrolysis device through the outlet 12a at the top of cell A. All of the slots in the steel frames, along with the alternating slots in the polyester frames the whole of the bipolar electrolysis device that forms the chamber are vertically connected and form one common Channel that carries the hydrogen upwards and the caustic solution downwards into the common cathode outlet at the bottom of the electrolysis device leads, this drain is equipped with a gas lock 12c, which is kept full of catholyte is to prevent hydrogen from escaping at the foot end of the cell stack A to prevent and to ensure a separation of the hydrogen from the catholyte.

The titanium back plates β are with the dimensionally stable metal anodes 5 connected by vertical ribs 6a, which in right Angles to the inverted U-ribs 5b of the anodes 5 run and they cut through and welded to the titanium back plates 6 and to the inverted TJ sections 5 of the anodes. the

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Titanium ribs 6a and the inverted U-ribs are distributed so that the voltage drop between the back plates 6 and the anodes 5 is smallest.

The titanium back plates 6 can mechanically with the base plates 3d of the cathode frame 3 by screwing, welding or like that can be connected. To improve the electrical The contact surfaces of the base plates 3d and the titanium back plates 6 are partially made contact with a sandblast treated and coated with a sprayed-on thin layer of soft metal, such as copper, lead and the like.

In each cathode frame 3 suction ports 3b are provided to the deposition of diaphragm material, indicated by dashed lines 10 in FIGS. 9 and 10, on the cathode sieves 3a is indicated to facilitate. When the suction nozzles 3b are not in use for the diaphragm separation they closed by caps 3g. In the case of the horizontal »planar cathode screens 3a, however, woven asbestos diaphragm fabrics can also be used or any other suitable type of prefabricated diaphragm material in lieu of that by suction deposited diaphragms are used.

As illustrated in FIGS. 19 and 20, the active areas of the dimensionally stable, permanent metal anodes 13 and 5 are available in various forms on the basis of titanium or tantalum, equipped with electrical conductive electrocatalytic coatings of mixed oxides of titanium or tantalum and a metal oxide of the platinum group or with a coating of other metal oxides or metals of the platinum group. The base of titanium or tantalum on top of this Coatings applied and grounded can take various forms, e.g. B. the form of solid rolled solid titanium plates, from perforated plates, slotted, reticulated titanium plates, Titanium braid and rolled titanium braid, woven titanium wire

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or sieve, of titanium rods and rails or it can be Corresponding tantalum shapes and other metal plates and shapes are all about $ 50 Gaps. The preferred method of applying the coatings is that of chemical deposition in the form of solutions that are painted on, dipped or sprayed or as a Veils or electrostatic spray coatings can be applied, baked on the anode base or thrown through Electroplating can be applied when platinum group metal coatings are used.

FIG. 19 is an enlarged detail of a base made of titanium mesh for the anodes 13 and 5, as is indicated in the circle labeled 5H "in FIG. 16, the open parts or gap parts 5c of the meshes exceeding the solid parts 5d of the meshes The open area of the mesh should be 30-60 $ of the metal area of the anode area, preferably 50-53 $ _s Figure 20 shows an enlarged detail of a titanium anode base as indicated in the circle labeled 51 in Figure 12, with coated , spatially separated rods 5e form the active surface of the anode and the open parts between the rods are larger than the solid surfaces of the rods. Part of the cathode screen is shown at 3a and part of the diaphragm is shown at 10. This open or voided construction facilitates the smooth passage of electrolysis gases released at the anodes upwards through the anode surfaces into the electrolyte and gas space above the anodes and eliminates The problem of the gas envelope (shielding) that occurs when using graphite anodes.

Those illustrated in FIGS. 19 and 20 and with 13 in FIG Anode base, die.with an electrically conductive electrocatalytic Cover is almost as flexible as a sheet of cardboard and can be made into any shape you want

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be bent, for example into the curved legs 5a or into the inverted U-ribs 5b, and can for example welded to the titanium back plates 6 and ribs 6a or to the floor plates C1, C2, C3 etc. or in some other way attached to it without losing any of the coating on the base.

Figures 15 and 16 illustrate an "alternative construction in the separate anode areas 5f and 5g with help be fastened by screws and nuts 14a to the back plates 6 by screwing them to titanium brackets 14, the are welded to the back plates 6. It is only necessary to detach the anode surfaces 5f and 5g from the back plates 6 required to remove the nuts 14a, whereupon the anode surfaces 5f or 5g removed from the clamps 14 and new ones Installed anode surfaces or the old can be re-coated and re-installed. This construction allows the use of smaller facilities for anode activation (coating) and reactivation (recoating). However, the assembly and disassembly require a little more work and there is a voltage drop at the screw connections on. The base plate 1 (FIG. 18) and the cover plate 2 (FIG. 17) are each provided with reinforcing ribs 1b and 2b and the cell stack A is held together by a plurality of long threaded screws 15 which are inserted between the The bottom and top plates run. Insulating supports 1c are provided for the base plate 1.

The cathode screens of these cells are specially tailored to a load with a current density of 3000 A / m or more, so that the cells according to the invention can be operated at higher current densities and are therefore more efficient are considered prior art cells.

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Two embodiments according to the invention are described here has been, however, it is clear that the principles of the invention can also be embodied in various other embodiments and that the cell can be used for purposes other than those specifically described can be used and as a single unit in the form of a monopolar cell or as a Multiple unit in the form of a bipolar cell, as described here, can be used v / ground.

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300816/1153

Claims (1)

CASE: 267044 PATENT CLAIMS 1. Horizontal, bipolar diaphragm electrolysis cell, which has a plurality of horizontal cell units which are in bipolar connection with one another, each cell unit consisting of an anode chamber (E1, E2 ...), which is set up for receiving an anolyte liquid is, and a cathode chamber which is set up to receive a catholyte liquid, a frame (A1, A2 ..., 3 or 4) which surrounds each anode chamber and each cathode chamber, means for electrical insulation (G, 4, 4a, 4b _f 4d) the frame surrounding the chambers against a flow of electricity from the walls of the anode chambers and the walls of the cathode chambers, a horizontal, essentially planar anode (I b «w, 5) made of a valve metal, has' 60 $ gaps and carries an electrically conductive electrocatalytic coating, in each anode chamber _f einsn diaphragm (10) and a Metallkathodensieb (D1, D2 ... and 3a) in each cathode chamber, Mitt - approximately 30 eln (J, J1 ... or 7, 7a) to introduce Aaplyt liquid into each anode chamber and mean » {%, K1 etc. 8d, 11, 11a) for removing anolyte gas from the cathode compartment, means (M, M1 and 12, 3e, respectively) for removing catholyte liquid and catholyte gas from the catholyte chambers, and means for conveying electrical current through each cell unit. - 22 309816/1 153 ?., Cell according to claim 1, characterized in that the anode chambers are surrounded by a frame (4) made of insulating material and the cathode chambers are surrounded by a metal frame (3) are surrounded and these frames are stacked on top of each other, with each between the cathode frame (3) ″ and the one above Anode frame (4), a cathode screen (3a) and a diaphragm (10) are located. 3. Cell according to claim 1, characterized in that the anode chambers (E1, E2 ...) of metal frames (A1, A2 ...) are surrounded by an inert lining (G-), the cathodes - chambers are surrounded by metal frames (A1, A2 ... or 3), which The anode and cathode frames are isolated from each other and stacked on top of each other, each between the cathode frame and the overlying anode frame is a cathode screen (D1, D2 ... or 3a) and a diaphragm (10). 4 .. Cell according to claim 3, characterized in that the inert lining (G) in the anode frame (A1, A2 ...) is a valve metal. 5. Cell according to claim 1, characterized in that each frame (A1, A2 ...) surrounding an anode chamber and a cathode chamber is made of metal, the anode chambers 'and' Cathode chambers in each frame are separated by a horizontal metal plate (C1, C2 ...) that contains a cathode screen (D1, D2 .-. ·) And a diaphragm on its upper side and the anodes (i) on their lower side, and that the metal frames from each other are isolated and stacked on top of each other. 6. Cell according to claim 5, characterized in that the anode chamber in each frame with a corrosion-resistant Lining (G) is fitted under the cell conditions is constant. .-.- ,,;. - 23 3 0 9 8 16/1153 7. Cell according to claim 2, characterized in that the cathode frames are equipped with electrically conductive metal base plates (3d) and the valve metal anodes (5)
Have valve metal back plates (6) which are in electrically conductive contact with the cathode bottom plates. 8. Cell according to claim 7, characterized in that the valve metal anode plates by electrically conductive valve metal connections connected to the valve metal backplates. 9. Cell according to claim 1, characterized in that it has a metal path for conducting the electrical current from the conductive metal bottom plates to the valve metal anode surfaces, a metal path for conduction of the electrical Current from the metal cathode screens to the metal base plates and an anolyte liquid to conduct the electrical Current from the anode surfaces to the cathode sieves. 10. Cell according to claim 7, characterized in that the electrical contact surfaces between the cathode bottom plates (3d) and the anode back plates (6) with a layer are covered from soft metal. 11. Cell according to claim 3, characterized in that the electrically conductive metal base plates to the metal cathode frame are welded. 12. Cell according to claim 7, characterized in that the valve metal anodes are removable with the valve metal back plates are connected. 13. Cell according to claim 1, characterized in that the frames with anolyte feed lines (J, J2 or 7, 7a, 8) - 24 309816/1 153 «Γ and anolyte gas outlets (K, K1 or, 8d, 11) in each anode chamber and with catholyte gas outlets (L, L1 or 12) and Catholyte liquid outlets (M, M1 or 12, 12b) in each Cathodic chambers are equipped. 14. Cell according to claim 2, characterized in that the anode frame have balcony-like projections which the Feed the anolyte liquid into the anode chambers and allow anode gas to escape from the anode chambers and isolating spacers on one side of the cathode frames (9) with guide surfaces (9a), which from an upper balcony to the balcony-like projection of the next lower anode frame deflect overflowing anolyte liquid. 15. Cell according to claim 2, characterized in that the metal cathode frames (3) have electrically conductive metal base plates (3d), the cathode screens (3a) on the metal cathode frames are welded on and the sieves are supported by iron metal ribs (3c) which extend from the base plates extend upwards and are welded to the screens. 16. A cell according to claim 14, characterized in that a single anolyte liquid inlet feeds the entire Absorbs anolyte liquid and enters it at the bottom of the cell stack Drain (7b) is provided for excess anolyte liquid. 17. Cell according to claim 1, characterized by means for generating a positive pressure gradient from each anolyte chamber to each catholyte chamber, which draws the anolyte liquid in the anode chambers through the diaphragms and sieves into the cathode chambers drives. 18. Cell according to claim 17, characterized in that the. Means for generating the positive pressure gradient of each - 25 ~
309816/1153 Include anolyte chambers in each catholyte chamber which attach to the catholyte gas removal device (L1 or 12a) are connected. 19. Cell according to claim 17, characterized in that it has means for generating a pressure gradient from the anode chamber has to the cathode chamber. 20. Cell according to claim.1, characterized in »that the means for removing catholyte liquid and catholyte gas from the cathode chambers with a standard sanitary line (11, M1 or * 12, 12a) extending from the top to the The lower end of the bipolar cell extends, see in connection, the upper end of the manifold with a catholyte gas outlet and the lower end of the collecting line is connected to a drain line for catholyte fluid * 21. Cell according to claim !, characterized in that the cathode frames have devices for sucking on each frame to remove diaphragm material to deposit the cathode sieves. 22. Cell according to claim 1, characterized in that the planar valve metal anodes have the shape of a Haeohenwerkes to have. 23. Cell according to claim 1, characterized in »that the planar valve metal anodes consist of rods that lie in the same horizontal plane. 24. Electrolytic cell unit, characterized by an anode chamber and a cathode chamber, one the anode chamber and the frame surrounding the cathode chamber (A1, A2. ·. or 3, 4), an anolyte liquid in the anode chamber, a catholyte liquid in the cathode chamber, a horizontal essentially - 26 - 3098 16/115 3 2670 « union planar valve metal anode (I "or 5), the gaps and has an electrically conductive electrocatalytic coating, in the anode chamber, a diaphragm (10) and a metal cathode screen (D1, D2 ... "or 3a) between the anode and cathode chamber, means (J, J1 ... "or 7, 7a) for feeding of anolyte liquid in the anode chamber and means (K, K1 "or 8d, 11, 11a) for removing anolyte gas from the anode chamber, means (M, M1 or 12, 3e) for removing KathoDyte liquid and catholyte gas from the catholyte chamber and Means for conveying electrical power through the cell unit. 25. Horizontal, bipolar diaphragm electrolysis cell, which has a plurality of cell units ir, bipolar connection with one another, wherein each cell unit consists of an anode chamber, which is set up for the reception of an anolyte liquid, and a cathode chamber for the reception a catholyte liquid is set up, an anode frame surrounding each anode chamber, a metal cathode frame, surrounding each cathode compartment, means for isolating the frame surrounding the anode compartments and that of the cathode compartments surrounding frame so that no electricity flows through the walls of the chambers, a horizontal, essentially planar valve metal anode (I or 5), which has gaps and an electrically conductive electrocatalytic coating, in each anode chamber, a diaphragm (10) and a metal cathode screen (D1, D2 ... or 3a) between each anode and cathode chamber, Means for feeding anolyte liquid into each anode compartment and removing anolyte gas therefrom Chambers, means for removing catholyte liquid and catholyte gas from the catholyte chambers and means of conveyance of electrical current through each of the cell units. 26. Method for the electrolysis of a saline solution in a bipolar diaphragm electrolytic cell, the horizontal im - 27 309816/1153 ie has substantially planar valve metal anodes with through openings therein, in which the gaps are substantially the same size as the solid metal surfaces of the anode, the cell having diaphragms and cathode screens below the anodes, characterized in that the gases released at the anodes upwards are passed through the openings of the anodes into an anode gas space above the anodes and discharged from the cell, the saline solution is passed downwards through the diaphragms and cathode sieves into a cathode chamber, the gases and liquids formed in the cathode chamber are separated and discharged separately from the cell. - 28 3 0 9 8 16/1153 Lee r side