CA1106312A - Electrolytic cell with membrane - Google Patents
Electrolytic cell with membraneInfo
- Publication number
- CA1106312A CA1106312A CA306,441A CA306441A CA1106312A CA 1106312 A CA1106312 A CA 1106312A CA 306441 A CA306441 A CA 306441A CA 1106312 A CA1106312 A CA 1106312A
- Authority
- CA
- Canada
- Prior art keywords
- container
- anode
- anodes
- cathodic
- cell
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
- C25B1/00—Electrolytic production of inorganic compounds or non-metals
- C25B1/01—Products
- C25B1/34—Simultaneous production of alkali metal hydroxides and chlorine, oxyacids or salts of chlorine, e.g. by chlor-alkali electrolysis
- C25B1/46—Simultaneous production of alkali metal hydroxides and chlorine, oxyacids or salts of chlorine, e.g. by chlor-alkali electrolysis in diaphragm cells
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
- C25B9/00—Cells or assemblies of cells; Constructional parts of cells; Assemblies of constructional parts, e.g. electrode-diaphragm assemblies; Process-related cell features
- C25B9/40—Cells or assemblies of cells comprising electrodes made of particles; Assemblies of constructional parts thereof
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
- C25B9/00—Cells or assemblies of cells; Constructional parts of cells; Assemblies of constructional parts, e.g. electrode-diaphragm assemblies; Process-related cell features
- C25B9/70—Assemblies comprising two or more cells
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/006—Water distributors either inside a treatment tank or directing the water to several treatment tanks; Water treatment plants incorporating these distributors, with or without chemical or biological tanks
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/008—Control or steering systems not provided for elsewhere in subclass C02F
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Inorganic Chemistry (AREA)
- Electrolytic Production Of Non-Metals, Compounds, Apparatuses Therefor (AREA)
- Electrodes For Compound Or Non-Metal Manufacture (AREA)
Abstract
267.078 CAM:cb ELECTROLYTIC CELL WITH MEMBRANE
AND METHOD OF OPERATION
ABSTRACT OF THE DISCLOSURE
Describes electrolytic cell with dimensionally stable anodes, non-porous ion-selective membranes separating said anodes from the cathode compartment, and a porous, static bed of loose, conducting cathodic material in the cathode compartment, extending between the conductive walls of the cathode compartment and the membrane and contacting the conductive walls of the cathode and said membranes to carry current between the walls of the cathode compartment and said membranes. This construction reduces the electrodic gap to substantially the thickness of the membranes and presses the membranes against the anodes. It produces greater uniformity of current density over the entire electrodic area, substantially free from localized differences of cur-rent density which tend to cause deterioration of membranes by the creation of localized mechanical and electrical stresses in other types of cells, and provides a method for carrying current from the effective cathodic surface to the walls of the cathode compartment.
AND METHOD OF OPERATION
ABSTRACT OF THE DISCLOSURE
Describes electrolytic cell with dimensionally stable anodes, non-porous ion-selective membranes separating said anodes from the cathode compartment, and a porous, static bed of loose, conducting cathodic material in the cathode compartment, extending between the conductive walls of the cathode compartment and the membrane and contacting the conductive walls of the cathode and said membranes to carry current between the walls of the cathode compartment and said membranes. This construction reduces the electrodic gap to substantially the thickness of the membranes and presses the membranes against the anodes. It produces greater uniformity of current density over the entire electrodic area, substantially free from localized differences of cur-rent density which tend to cause deterioration of membranes by the creation of localized mechanical and electrical stresses in other types of cells, and provides a method for carrying current from the effective cathodic surface to the walls of the cathode compartment.
Description
This invention concerns, generally, an electrolyti I cell with anocles cover-ed by an ion-selective membrane whercin the cathode is formed by a static, porous bed of small con- I
' ducting particles, extending between the walls of the cathodej compartment and the walls Or the membranes and pressing said ¦
membranes against the anodes. In particular, the invention relates to a cell for the electrolysis Or aqueous solutions Or;
alkali metal halides, although it may be used for carrying out other electrolysis reactions, such as the electrolysis of other salts which undergo decomposition under electrolysis conditions, ror the electrolysis of IICl solutions, the ; electrolysis of water, organic and inorganic oxidations and reductions, etc.
~ecent]y, electrolytic cells have been developed which use ion exchange mernbranes instead of the more ; traditional asbestos diaphragms)especially for brine electro-~ lysis. Although they are electrolytically conductive under `i Iloperating conditions, such rnembranes are substantially ~- liMpermeable to the hydrodynamic flow of liquids and gases.
, In operation, the alkali metal halide brine is introduced - into the anodic compartmentl where gaseous halogen develops on the surfaces of the anode. The alkali metal ions are select~ively transported across the cationic membrane into ~the cathodic compartment, where the a]kali metal ions combine 1 25 i with the hydroxyls generated on the cathode by electrolysis of the water to form alkali metal hydroxide.
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,' Cells wlth cationic membranes offer numerous ~advantages over the conventional diaphragm cells. They perrni ;
' the production of relatively pure solutions of alkali metal ' hydroxide, not diluted with brine as in the case of the porous diaphragms, where subsequent separation and purifica-tion of the hydroxide is required, and also permit a more efficient and simplified operation of the electrolysis process.
, To fully utili%e the ch~iracteristics of the non-porous membranes, it is desirable to reduce to a minimum ' the distance between electrodes (i.e., the interelectrodic gap), which reduction has a remarkable effect on the opera~
ting voltage and hence on the energy efficiency of the electrolytic process.
, Commercial membranes are sensitive to current I -density, which must be maintained within certain optimal ~ limits for efficient operation of the membrane. The current ¦
i density should be ncarly constant over the entire surface, ,,so as to avoid the occurence of mechanical and electrical ' stresscs, which would irreversibly damage the membrane.
In the known membrane cells~ the optimation Or these parameters depends to a large extent on the structural tolerance limits and, in view of the size of the electrode surfaces in the commercial cells, relative to the ever 25 l smallcr electrode spacings (of the order of some millimeters) the inevitable deviations from the most exact parallelism between the anodic and cathodic surfaces cause more or less marked var~atiol-s of the urrent density ove~ tho surlaoe o ,,,, I ~ , , , ,, . . . .
" . : ' , of the membr~ne. As a re!,ult., past ~forts to assure a correct curren~ denslt~
locally, on various areas o~ the membrane, have not been successful.
In one partlcular aspect the present invention provides an electrolysis cell comprising an anode compartment containing an elec-troly-te per-meable anode and a cathode compartment containing a cathode separated by an ion exchange membrane supported on the electrolyte permeable anode, means to impress an electrolysis current on the cell, means for introducing catholyte to the cathode compartment, means for introducing catholyte to the cathode compartment, means for removing spen-t anolyte and electrolysis products from the anode compartment and means for removing spent catholyte and electro~ysis products from the cathode compartment, the cathode being a porous static bed of electrically conductive catholyte-resistant particulate filling material which presses the membrane against the anode.
In another particular aspect the present invention provides an electrolytic cell comprising a container of cathodically resistant metal, a valve metal top on said container electrically insulated from said container, at least one tubular valve metal anode connected to and extending from said top sub-stantially to the bottom of said container, perforations through a portion of the walls - of said anode inside said container and an imperforate portion of said anode extending from just below the top of said container to said valve metal top, said anode being open at both ends, an ion permeable membrane on the perforated walls of said anode, a porous, static bed of electrically conductive particulate cathodic filling material between said membrane and the walls of said container, openings into the tubular anode through the bottom of said container, means to feed electrolyte into the bottom of said tubular anode, means to elec~rically insulate said anode at the top and bottom from said container, means to convey positive electric current to said anode, means to convey negative electric current from said container, means to conduct gaseous products produced on said anode and electrolyte out of said container, means to conduct gaseous cathodic products produced in said container out of said container, means to lntroduce liquid into the cathodic compartment of ~r~ - 4 -cm/
3~
said container between said mcmbrane and the w~l.ls of s~id con-tainer and rneans to convey liquid cathoclic products out oE said container.
In yet another particular aspect the present invention provides an electrolysis cell comprising a cathodic container, a valve metal cover for said container, a plurality of tubular valve metal anodes with walls permeable to liquids inside said container and secured to ~he cover of said container, tubular ion exchange membranes on the outer surfaces of said tubular anodes delimiting and hydraulically separating the cathodic compartment inside said container from the anodic compartment inside said tubular anodes, a bottom~closure for said container means in said closure forming hydraulic connection between the interior of said tubular anodes and an electrolyte, distributor external to the cathodic container, a static, porous bed of conductive particulate filling material resistant to the cathodic conditions in said cathodic container to a height just below the cover of the container, pressing said membranes against said anodes, said static, porous hed being in electrical contact with the inner walls of the cathodic container and functioning as the cathodic at the surface adjacent to said membranes, a tank for receiving impoverished electrolyte and anodic gas connected with the upper ends of said tubular anodes, means for passing electrolysis current between said anodes and the cathodic of the cell and means for recovering gaseous and liquid products from the cathodic compartment.
In yet another particular aspect the present invention provides the method of reducing the interelectrode g~p in an electrolysis cell having an anode compartment, a cathode compartment, a porous and permeable anode in the anode j compartment and a cathode in the cathode compartment, an ion exchange membrane i between the anode and the cathode compartment and means to pass an electrolysis current through said cell, which comprises pressing said membrane against said porous anode surface by a porous, static bed of conducting particulate filling material between the walls of sald cathode compartment and said membrane and con-ducting electric current through said anode, said membrane and said particulate ~ ~illing material between said membrane and the walls of said cathode compartment.
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In a further particular aspect th~ present lnvention E~rovldes an electrolysis cell havincl an anode compartment and a cathode compartment, electrodes comprising an anode and a ca-thode, means to pass an electrolysis current between said anode and said cathode and an ion exchanye membrane between said electrodes, the method of reducing the interelectrodic gas to approximately - the thickness of said membrane, which comprises placing said membrane against one of said electrodes, pressing said membrane against said electrode by a porous, static bed of conduc-ting particulate filling material between said membrane and the other electrode, and passing the electrolysis current bctween said electrodes through said static bed.
In still a further particular aspect the present invention provides an electrolytic cell having electrocatalytically coa-ted valve metal anodes, a cathode and ion selective cationic membranes substantially impermeable to the flow of liquids and gases therethrough, between the anodes and cathodes, the method of maintaining ; the current density substantially constant and of reducing mechanical and electrical stresses on said membranes which comprises applying said membranes on said anodes, substantially filling the space between the membranes and the electrically conducting walls of the cathodes with, porous cathodic filling material in the form of chips, balls, beads, cylinders, Raschig rings, metallic wool or other particles or strands pressing said mbranes against said anodes, passing an electrolysis current from said anodes through said membranes and said filling material to the electrically conducting walls of said cathodes and collecting the anodic gases and liquids separate from the cathodic gases and liquids.
Various other advantages of the invention will become apparent from the description which follows.
The preferred embodiment of the cell of this invention comprises a cathodic container of steel or other conductive material resistant to corrosion in the catholyte environment which is closed at the upper end by a plate or cover ' of titanium or other valve metal, which is passivatable under conditions of anodic polarization and which has at least one but preferably a serles of tubular ~ cm~ - 4b -. .
anodes welded into holes i.n the tltanlum cover plate which extend almost the entlre depth of the contalner, with the walls of the tubular anodes (except the upper part of the anode walls near the welds to the titanium plate) perforated so as to be permeable to liqui.ds and gases.
The anodes are dimensionally stable and, -typlcal].y, are of titanium or other valve metal, coated on at .Least part of the active surface with an electroconducting, electrocatalytlc deposit of material resistant to the anodic conditions and not passivatable, preferably a deposit of noble metals such as platinum, palladium, rhodium, ruthenium and , J' cm/ 5 . -. , .
.,`, , . l iridium, or oxides or mixed oxides thereof. The lower ends fof the tubular anodes are closed by plugs Or inert, pre- f ferably plastic, material provided with coaxial threaded . ,.
holes. The permeable walls of the tubular anodes are com-: pletely covered externally by the membranes so as to delimit the anodic compartment inside the tubular anodes.
The lower end of the cathode container is closed . li . by a plate, prcferably of inert plast:ic material, and is ;~ provided with means for feeding brine or ot}ier anolyte into . 10 the interior of the various tubular anodes, typically by - means of inlets Or plastic material whose flanges form a . seal against the bottom plate of the container. The anolytel is fed through tubular connectors screwed into the th:readed holcs Or the closing plugs of the tubular anodes.
fl The container in the preferred embodi.rnent is !i provided with an outlet in the upper part for the emergence , of the cathodic gas, with a discharge opening in the lower Il part for discharge of the catholyte and with an inlet pipe ¦~l for recycling the dilute catholyte or ~rater into the I., cathodic c.ompartment. The anodes welded to the cover of the fi . container comrnunicate through the holes in the cover with a ¦
. c`namber above the container where the anodic gas separates . from the electrolyte, escapes from an outlet and flows to a ¦
il gas recovery system and the electrolyte is recycled to a I' resaturation systenn before reintroduced into the cell. . .
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The cathode of the cell consists of a porous, static bed of loose, conducting cathodic materlal in the form of chips, beads, balls, cylinders, Raschig rings, metallic wool or other particles with which the container is¦
completely filled to a height corresponding at least to the ¦
height of the perrneable walls of the tubular anodes covered by the membranes. The filling of cathodic material is in contact with the inner walls of the container and with the outer surfaces of the membranes on the various tubular anodes and presses against the membranes. The conductive cathoclic fil]ing material may be graphite, lead, iron, nickel, cobalt, vanadiurn, molybdenurn, zinc, or alloys thereof, intermetallic compounds, compounds of hydridization, carbid-ization and nitridization of metals, or other materials i having good conductivity and resistance to the cathodic conditions.
l Materia]s exhibiting lo~ hydrogen overpotential - l, such as iron, nickel and alloys thereof are particularly 1 suitable for brine electrolysis. On the contrary, for ' instances, for the reduction of FeIII to FeII in an acidic sulfate catholyte solutlon using an anionic rnembrane and evolving oxygen on the anode, particulate materials having al -high hydrogen overpotential such as lead and lead alloys i are preferable. The cathodic filling material may also com-l ;
~i prise p]astic, ceramic, or other inert, non conductive, material coated with a layer of the electrically conductive and cathodically resistant materials mentioned.
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The titanium plate or cover to which the tubular ' anodes are welded is ~Lnsulated from the cathod:Lc compartment ' by an insulating gasket. It is connected to the positive terminal Or the current distribution network, and the ,; cathoclic compartment is connected to the negative terminal ¦
of the distribution network.
' The mass of the cathode filling is cathodically polarized and functions as cathode and the porosity of the static bed of cathodic material permits rapid evacuation of ' ,' the cathodic gas and contributes to protect cathodically the, ,; inner walls of the cathode container. ! ~r The electrode spacing is reduced to little more than the thickness of the membranes by the local def'lection ~ of the electrolytic current flux lines on the geometrically ,, undefinecl surfaces of the cathode material, rcpresented by , the particles of the bed directly adjacent to the surfaces of the membrarles, and on the geometrically undefined sur-' faces of the meshes of the permeable walls of the tubular ¦ anodes on which the membranes are applied.
I The spacing betueen the cathodic filling material ; ' and the anodes remains substantially constant throughout I
the electrolysis process. ¦
This conriguration of the cell produces excellent ' uniformity of the current density on the entire electrodic ', area, without s~ldden localized differences which would tend .`
¦ll to deteriorate the membranes by the creation of mechanical ,, and electrical stresses.
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Another advantage of the preferred embodiment of the cell of this inventiorl, which comprises a plurality of tubular anodes, is its compactness, as the ratio between ` the extent of the electrode surfaces and the volume occupied by the cell is much greater than in prior cornmercial membrane cells~ ¦
~he drawings of the preferred embodiment illustrate the anodes as circular tubes in a rectangular container, which is preferred because of the greater uniformity of the ~ current density and lower cost. It will be understood, ho~ever, that anodes tubes of other shapes, such asoval, rectangular, hexagonal and other polygonal shapes, may be ' -used and are within the scope of the word "tubes" as used herein and that the cel.l container can be rectangular, cylindrical or other shapes. A less prererred embodiment of the invention is a cyli.ndrical container housing a single, concentric cylindrical anode; however, according to this ernbodlment a number of cells are necessary to attain the " desired capacity. It wi]l also be understood that while ,' the cell of this :invention is described in connection with the production of chlorine, it may be used for electrolytic processes producing other products.
i In the accompanylng drawings, which illustrate the preferred ermbodiment of this invention, Fig. 1 ls a 25 !~ sectional view and Fig. 2 is a sectional plan view along line 1-1 of Fig. 1, with parts above the section line illu erate~ n hlsl~ e~.
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As illustrated in Fig. 1, the cell comprises a rectangular cathodic container 1 of steel or nickel, or alloys thereof, or of other conductive and cathodicallY
resistant metal. A cover 2 of titanium or other anodically passivatable valve metal, bolted to the container 1, closes the container at the top. An insulating gaslcet 3 is provided between the cathodic container 1 and the titanlum cover 2. Tubular anodes 4 of titanium are welded in holes ; in the cover 2 and extend above the cover as illustrated.
The walls of tubular anodes 4 are provided with holes or .
; other perforations, which begin at a short ~istance below the cover 2 and extend to the bottom of the anodes ll. The perforated portions 6 of the anodes may be formed of reticulated or expanded titanium sheet welded to the imperforate top section 5, or formed integrally therewith.
The surface of the perforated portions 6 o~ the tubular anodes 4 is suitably coated with an electrocatalytic deposlt, which is non-passivatable and resistant to anodic condltions typically containing noble metals or oxides of noble metals.l The tubular anodes are closed at the lower end by a plug or ¦
closure 7 of tltanium welded to the lower end of each anode 4, or, preferably, as indicated in Fig. 1, Or chemically resistant plastic material, such as PVC or the liXe~ provided uith a coax:ial, threaded hole 7a. -¦ ;
The cationic membrane 8, preferably tubular, is slipped over the anodes 4 and fastened to the imperforate top of the anodes and to the outer cylindrical surface of the plug 7 by means of bands of plastic material 9. This .
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Stelling i5 particlllarly easy and forms a perfect hydraulif seal between the membranes and the perrorated sections of the anodes 4 which is dirficult to obtain in conventional filter press cells.
i The cationic membrane 8 is preferably permeable to cations and impermeable to the hydrodynamic flow of the liquid and gas. Suitable materials for themembraneS are fluoridized polymers or copolymers containing sulfonic groups. Such materials are sufficiently flexible and are produced in tubular form by extrusion or hot gluing of flat sheets. The thickness of such membranes is in the order Or one-tenth of a m:illimeter.
The container 1 is turne(l 180 to facilitate fill-ing and is filled with the cathodic material 10. The I container is then closed with a rectangular plate 11 per~
forated at the base of each of the anodes 4 and, preferably,¦
Il of inert plast~c material. A rectangular brine distribution, -¦~ box 12, also Or inert plastic material, is welded to the : !i plate 11 and is closed by a closure plate 13 equipped with l a brine inlet opening 14. A ~asket may be provided between !j the plate 11 and the flanged bottom of the rectangular container 1. The flanges Or the plate 11 may be bolted to the bottom flange on container 1 and the closure plate 13 ~I may be bolted to the bottom of the distribution box 12. The I brine distribution box is connccted to the interior of the ~ i~ anodes 4 by means Or tubular connectors 15, which are 1 1l¦ flanged at one end and threaded into the threaded holes 7a ~ o~ the closure plu~s 7 e~ls or kasketk 16 aro pro~1ded ~ I , ,, , , ' !
ll between the rlanges on the connectors 15 and the brine ; distribution bo~ 12.
The cathodic compartment is filled with particulat~
material to about the top of the permeable sections 6 of the ' tubular anodes 4~
The cathodic container is provided, near the upper part, at a level higher than that Or the particulate bed 10, !
with one or more outlets 17 for hydrog~en and, in its lower part, with at least one adjustable gooseneck outlet 18 for ' i . 10 discharging the ca-tholyte.
A distribution or spray tube 24, above the level of theparticulate material 10, extends hori~ontally over sub-stantially the entire length of the container 1 and is I equippcd ~lith a series of holes so as to permit the addition l Or water or catholyte to the cathodic compartment for dilut-I ing and regulating the conccntration of the alkali metal ; I hydroxide produced in the cathode compartment.
Preferably, water is continuously added into the I cathodic compartment through the distribution tube 24, in , order to dilute the hydroxide formed at the cathode and maintain the hydroxide concentration Or the catholyte erfluer t , rrom the cell within 25% and 43% by weight.
' Each Or the tubular anodes ~1 is connected at the I top to a rectangular tank 19 extending over the entire top li f the cell container 1. The electrolyte level in the tank 19 is maintained constant by a gooseneck discharge tube 20 for the electrolyte. The electrolyte discharged rrom tube 20 , is sent to the resaturation system before being recycled !l . .
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into the cell through the elect~olyte inlet 14.
The halogen produced on the anodes separates from the electrolyte in tank 19 and escapes through outlet 21.
, The plate or cover 2 to which the tubular anodes 4 1 are welded is directly connected to the positive terminal Or the electric power supply by means o~ the connection 22 and the cathodic container 1 is connected to the negative terminal by means of connection 23.
Fig. 2 is a sectional view along the line 1-1 o~
Fig. 1, with the elements Or the cell described with refer-ence to Fig. 1 indicated by the same numerals. The locatlon o~ the distribution tube 24 is indicated by bro'~en lines ¦
above the level of the particles Or cathodic material 10 in the cathode container 1.
~i ~ The cell shown comprises six tubu]ar anodes in a rcctangular casing, but it wi]l be understood that the nunber o~ anodes may be varied in the transversè direction, j, that more rows o~ anodes may be used, that the shape of the ¦
Il cell and the anodes may be di~rerent from that illustrated 1 and that other modifications and changes May be made within ¦
the spirit and scope o~ our invention.
The extent of the cylindrical sur~aces of the tubular anodes 4 is very large relative to the volume of ;~ the container 1, which permits high production rates in !l a compact cell, at substantially equal current density ; Il' throughout the cell when compared to the cells commonly used ¦, commercially. In operation, concentrated brine (120-310 - ¦, g/ltr) o~ NaCl, ror example, is fed through the inlet 14 int I distribution b~x 12 tDd rises throu~h each ~r the tubular , .
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anodes 4, on the electrocatalytically coated surfaces of which chlorine forms. The sodium ions traverse the catlonic¦
membrane and combine with the hydroxyls released at the cathode by electrolysis of the water, forming sodlum hydr- ¦
', oxide. The chlorine rises through the electrolyte contained . j inside the tubular anodes 4 and into tank 19, where it ' separates from the liquid and escapes through the outlet 21.
The rising chlorine bubbles provide a rapid upward flow of the electrolyte in the tubes 4.
The impoverished brine flows through the constant level outlet 20 and is recycled to the resaturation system , ~r before being reintroduced into the cell through the inlet 14.' The.hydrogen released on the surfaces of the porous ,; cathode bed adjacent the rnembrane 8 rises through the 1~ paJticle bed 10 and collects in the upper space of the cathodic container, whence it escapes through the outlet 17.
The sodiurn hydroxide solution is discharged through the adjustable gooseneck 18. The adjustable gooseneck 18 .
' maintains the level.of the catholyte at substantially the n same level as the top of the cathodic bed 10.
The catholyte may be cycled through a recovery system for the sodium hydroxide located outside the cell and t4e effluent~ dilute sodium hydroxide solution,rein-troduced into the cathodic compartment through the distribu-1 tion tube 24.
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Il The operat:i.ng temperature may vary between 30 and . 1000C and is pre~erably maintained at about 85C. The pH
of the anolyte may vary between 1 and 6 and the current l density may be between 1000 and 5000 ~/m2.
' While the cell and method of this invention have been described with reference to the illustrative drawings~
it is understood that numerous changes and alternati.ves may be used within the scope of this invention, that other . electrolysis processes may be carried out in the a,oparatus . described, that instead of titanium, other valve metals ; such as tantalum, ~irconium, molybdenum, niobium, tungsten and yttrium may be used in the construction ofthecell and that~
the static, conductive, particulate material may be used in other forrns of electrolysis cells.
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' ducting particles, extending between the walls of the cathodej compartment and the walls Or the membranes and pressing said ¦
membranes against the anodes. In particular, the invention relates to a cell for the electrolysis Or aqueous solutions Or;
alkali metal halides, although it may be used for carrying out other electrolysis reactions, such as the electrolysis of other salts which undergo decomposition under electrolysis conditions, ror the electrolysis of IICl solutions, the ; electrolysis of water, organic and inorganic oxidations and reductions, etc.
~ecent]y, electrolytic cells have been developed which use ion exchange mernbranes instead of the more ; traditional asbestos diaphragms)especially for brine electro-~ lysis. Although they are electrolytically conductive under `i Iloperating conditions, such rnembranes are substantially ~- liMpermeable to the hydrodynamic flow of liquids and gases.
, In operation, the alkali metal halide brine is introduced - into the anodic compartmentl where gaseous halogen develops on the surfaces of the anode. The alkali metal ions are select~ively transported across the cationic membrane into ~the cathodic compartment, where the a]kali metal ions combine 1 25 i with the hydroxyls generated on the cathode by electrolysis of the water to form alkali metal hydroxide.
~ 1 .
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.' 1, . .
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. . .
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.' I
,' Cells wlth cationic membranes offer numerous ~advantages over the conventional diaphragm cells. They perrni ;
' the production of relatively pure solutions of alkali metal ' hydroxide, not diluted with brine as in the case of the porous diaphragms, where subsequent separation and purifica-tion of the hydroxide is required, and also permit a more efficient and simplified operation of the electrolysis process.
, To fully utili%e the ch~iracteristics of the non-porous membranes, it is desirable to reduce to a minimum ' the distance between electrodes (i.e., the interelectrodic gap), which reduction has a remarkable effect on the opera~
ting voltage and hence on the energy efficiency of the electrolytic process.
, Commercial membranes are sensitive to current I -density, which must be maintained within certain optimal ~ limits for efficient operation of the membrane. The current ¦
i density should be ncarly constant over the entire surface, ,,so as to avoid the occurence of mechanical and electrical ' stresscs, which would irreversibly damage the membrane.
In the known membrane cells~ the optimation Or these parameters depends to a large extent on the structural tolerance limits and, in view of the size of the electrode surfaces in the commercial cells, relative to the ever 25 l smallcr electrode spacings (of the order of some millimeters) the inevitable deviations from the most exact parallelism between the anodic and cathodic surfaces cause more or less marked var~atiol-s of the urrent density ove~ tho surlaoe o ,,,, I ~ , , , ,, . . . .
" . : ' , of the membr~ne. As a re!,ult., past ~forts to assure a correct curren~ denslt~
locally, on various areas o~ the membrane, have not been successful.
In one partlcular aspect the present invention provides an electrolysis cell comprising an anode compartment containing an elec-troly-te per-meable anode and a cathode compartment containing a cathode separated by an ion exchange membrane supported on the electrolyte permeable anode, means to impress an electrolysis current on the cell, means for introducing catholyte to the cathode compartment, means for introducing catholyte to the cathode compartment, means for removing spen-t anolyte and electrolysis products from the anode compartment and means for removing spent catholyte and electro~ysis products from the cathode compartment, the cathode being a porous static bed of electrically conductive catholyte-resistant particulate filling material which presses the membrane against the anode.
In another particular aspect the present invention provides an electrolytic cell comprising a container of cathodically resistant metal, a valve metal top on said container electrically insulated from said container, at least one tubular valve metal anode connected to and extending from said top sub-stantially to the bottom of said container, perforations through a portion of the walls - of said anode inside said container and an imperforate portion of said anode extending from just below the top of said container to said valve metal top, said anode being open at both ends, an ion permeable membrane on the perforated walls of said anode, a porous, static bed of electrically conductive particulate cathodic filling material between said membrane and the walls of said container, openings into the tubular anode through the bottom of said container, means to feed electrolyte into the bottom of said tubular anode, means to elec~rically insulate said anode at the top and bottom from said container, means to convey positive electric current to said anode, means to convey negative electric current from said container, means to conduct gaseous products produced on said anode and electrolyte out of said container, means to conduct gaseous cathodic products produced in said container out of said container, means to lntroduce liquid into the cathodic compartment of ~r~ - 4 -cm/
3~
said container between said mcmbrane and the w~l.ls of s~id con-tainer and rneans to convey liquid cathoclic products out oE said container.
In yet another particular aspect the present invention provides an electrolysis cell comprising a cathodic container, a valve metal cover for said container, a plurality of tubular valve metal anodes with walls permeable to liquids inside said container and secured to ~he cover of said container, tubular ion exchange membranes on the outer surfaces of said tubular anodes delimiting and hydraulically separating the cathodic compartment inside said container from the anodic compartment inside said tubular anodes, a bottom~closure for said container means in said closure forming hydraulic connection between the interior of said tubular anodes and an electrolyte, distributor external to the cathodic container, a static, porous bed of conductive particulate filling material resistant to the cathodic conditions in said cathodic container to a height just below the cover of the container, pressing said membranes against said anodes, said static, porous hed being in electrical contact with the inner walls of the cathodic container and functioning as the cathodic at the surface adjacent to said membranes, a tank for receiving impoverished electrolyte and anodic gas connected with the upper ends of said tubular anodes, means for passing electrolysis current between said anodes and the cathodic of the cell and means for recovering gaseous and liquid products from the cathodic compartment.
In yet another particular aspect the present invention provides the method of reducing the interelectrode g~p in an electrolysis cell having an anode compartment, a cathode compartment, a porous and permeable anode in the anode j compartment and a cathode in the cathode compartment, an ion exchange membrane i between the anode and the cathode compartment and means to pass an electrolysis current through said cell, which comprises pressing said membrane against said porous anode surface by a porous, static bed of conducting particulate filling material between the walls of sald cathode compartment and said membrane and con-ducting electric current through said anode, said membrane and said particulate ~ ~illing material between said membrane and the walls of said cathode compartment.
!
4a -- - - ' '., , , ' ~ 6~Z
In a further particular aspect th~ present lnvention E~rovldes an electrolysis cell havincl an anode compartment and a cathode compartment, electrodes comprising an anode and a ca-thode, means to pass an electrolysis current between said anode and said cathode and an ion exchanye membrane between said electrodes, the method of reducing the interelectrodic gas to approximately - the thickness of said membrane, which comprises placing said membrane against one of said electrodes, pressing said membrane against said electrode by a porous, static bed of conduc-ting particulate filling material between said membrane and the other electrode, and passing the electrolysis current bctween said electrodes through said static bed.
In still a further particular aspect the present invention provides an electrolytic cell having electrocatalytically coa-ted valve metal anodes, a cathode and ion selective cationic membranes substantially impermeable to the flow of liquids and gases therethrough, between the anodes and cathodes, the method of maintaining ; the current density substantially constant and of reducing mechanical and electrical stresses on said membranes which comprises applying said membranes on said anodes, substantially filling the space between the membranes and the electrically conducting walls of the cathodes with, porous cathodic filling material in the form of chips, balls, beads, cylinders, Raschig rings, metallic wool or other particles or strands pressing said mbranes against said anodes, passing an electrolysis current from said anodes through said membranes and said filling material to the electrically conducting walls of said cathodes and collecting the anodic gases and liquids separate from the cathodic gases and liquids.
Various other advantages of the invention will become apparent from the description which follows.
The preferred embodiment of the cell of this invention comprises a cathodic container of steel or other conductive material resistant to corrosion in the catholyte environment which is closed at the upper end by a plate or cover ' of titanium or other valve metal, which is passivatable under conditions of anodic polarization and which has at least one but preferably a serles of tubular ~ cm~ - 4b -. .
anodes welded into holes i.n the tltanlum cover plate which extend almost the entlre depth of the contalner, with the walls of the tubular anodes (except the upper part of the anode walls near the welds to the titanium plate) perforated so as to be permeable to liqui.ds and gases.
The anodes are dimensionally stable and, -typlcal].y, are of titanium or other valve metal, coated on at .Least part of the active surface with an electroconducting, electrocatalytlc deposit of material resistant to the anodic conditions and not passivatable, preferably a deposit of noble metals such as platinum, palladium, rhodium, ruthenium and , J' cm/ 5 . -. , .
.,`, , . l iridium, or oxides or mixed oxides thereof. The lower ends fof the tubular anodes are closed by plugs Or inert, pre- f ferably plastic, material provided with coaxial threaded . ,.
holes. The permeable walls of the tubular anodes are com-: pletely covered externally by the membranes so as to delimit the anodic compartment inside the tubular anodes.
The lower end of the cathode container is closed . li . by a plate, prcferably of inert plast:ic material, and is ;~ provided with means for feeding brine or ot}ier anolyte into . 10 the interior of the various tubular anodes, typically by - means of inlets Or plastic material whose flanges form a . seal against the bottom plate of the container. The anolytel is fed through tubular connectors screwed into the th:readed holcs Or the closing plugs of the tubular anodes.
fl The container in the preferred embodi.rnent is !i provided with an outlet in the upper part for the emergence , of the cathodic gas, with a discharge opening in the lower Il part for discharge of the catholyte and with an inlet pipe ¦~l for recycling the dilute catholyte or ~rater into the I., cathodic c.ompartment. The anodes welded to the cover of the fi . container comrnunicate through the holes in the cover with a ¦
. c`namber above the container where the anodic gas separates . from the electrolyte, escapes from an outlet and flows to a ¦
il gas recovery system and the electrolyte is recycled to a I' resaturation systenn before reintroduced into the cell. . .
,'~ 11 ' , . ~ . ,.
:
~ 6~
The cathode of the cell consists of a porous, static bed of loose, conducting cathodic materlal in the form of chips, beads, balls, cylinders, Raschig rings, metallic wool or other particles with which the container is¦
completely filled to a height corresponding at least to the ¦
height of the perrneable walls of the tubular anodes covered by the membranes. The filling of cathodic material is in contact with the inner walls of the container and with the outer surfaces of the membranes on the various tubular anodes and presses against the membranes. The conductive cathoclic fil]ing material may be graphite, lead, iron, nickel, cobalt, vanadiurn, molybdenurn, zinc, or alloys thereof, intermetallic compounds, compounds of hydridization, carbid-ization and nitridization of metals, or other materials i having good conductivity and resistance to the cathodic conditions.
l Materia]s exhibiting lo~ hydrogen overpotential - l, such as iron, nickel and alloys thereof are particularly 1 suitable for brine electrolysis. On the contrary, for ' instances, for the reduction of FeIII to FeII in an acidic sulfate catholyte solutlon using an anionic rnembrane and evolving oxygen on the anode, particulate materials having al -high hydrogen overpotential such as lead and lead alloys i are preferable. The cathodic filling material may also com-l ;
~i prise p]astic, ceramic, or other inert, non conductive, material coated with a layer of the electrically conductive and cathodically resistant materials mentioned.
~ "'`' ' , . . , . ~ .
r 6~
, !
The titanium plate or cover to which the tubular ' anodes are welded is ~Lnsulated from the cathod:Lc compartment ' by an insulating gasket. It is connected to the positive terminal Or the current distribution network, and the ,; cathoclic compartment is connected to the negative terminal ¦
of the distribution network.
' The mass of the cathode filling is cathodically polarized and functions as cathode and the porosity of the static bed of cathodic material permits rapid evacuation of ' ,' the cathodic gas and contributes to protect cathodically the, ,; inner walls of the cathode container. ! ~r The electrode spacing is reduced to little more than the thickness of the membranes by the local def'lection ~ of the electrolytic current flux lines on the geometrically ,, undefinecl surfaces of the cathode material, rcpresented by , the particles of the bed directly adjacent to the surfaces of the membrarles, and on the geometrically undefined sur-' faces of the meshes of the permeable walls of the tubular ¦ anodes on which the membranes are applied.
I The spacing betueen the cathodic filling material ; ' and the anodes remains substantially constant throughout I
the electrolysis process. ¦
This conriguration of the cell produces excellent ' uniformity of the current density on the entire electrodic ', area, without s~ldden localized differences which would tend .`
¦ll to deteriorate the membranes by the creation of mechanical ,, and electrical stresses.
` ' ' -8-I , .
. I
Another advantage of the preferred embodiment of the cell of this inventiorl, which comprises a plurality of tubular anodes, is its compactness, as the ratio between ` the extent of the electrode surfaces and the volume occupied by the cell is much greater than in prior cornmercial membrane cells~ ¦
~he drawings of the preferred embodiment illustrate the anodes as circular tubes in a rectangular container, which is preferred because of the greater uniformity of the ~ current density and lower cost. It will be understood, ho~ever, that anodes tubes of other shapes, such asoval, rectangular, hexagonal and other polygonal shapes, may be ' -used and are within the scope of the word "tubes" as used herein and that the cel.l container can be rectangular, cylindrical or other shapes. A less prererred embodiment of the invention is a cyli.ndrical container housing a single, concentric cylindrical anode; however, according to this ernbodlment a number of cells are necessary to attain the " desired capacity. It wi]l also be understood that while ,' the cell of this :invention is described in connection with the production of chlorine, it may be used for electrolytic processes producing other products.
i In the accompanylng drawings, which illustrate the preferred ermbodiment of this invention, Fig. 1 ls a 25 !~ sectional view and Fig. 2 is a sectional plan view along line 1-1 of Fig. 1, with parts above the section line illu erate~ n hlsl~ e~.
'' , ' ' .
;3~Z
As illustrated in Fig. 1, the cell comprises a rectangular cathodic container 1 of steel or nickel, or alloys thereof, or of other conductive and cathodicallY
resistant metal. A cover 2 of titanium or other anodically passivatable valve metal, bolted to the container 1, closes the container at the top. An insulating gaslcet 3 is provided between the cathodic container 1 and the titanlum cover 2. Tubular anodes 4 of titanium are welded in holes ; in the cover 2 and extend above the cover as illustrated.
The walls of tubular anodes 4 are provided with holes or .
; other perforations, which begin at a short ~istance below the cover 2 and extend to the bottom of the anodes ll. The perforated portions 6 of the anodes may be formed of reticulated or expanded titanium sheet welded to the imperforate top section 5, or formed integrally therewith.
The surface of the perforated portions 6 o~ the tubular anodes 4 is suitably coated with an electrocatalytic deposlt, which is non-passivatable and resistant to anodic condltions typically containing noble metals or oxides of noble metals.l The tubular anodes are closed at the lower end by a plug or ¦
closure 7 of tltanium welded to the lower end of each anode 4, or, preferably, as indicated in Fig. 1, Or chemically resistant plastic material, such as PVC or the liXe~ provided uith a coax:ial, threaded hole 7a. -¦ ;
The cationic membrane 8, preferably tubular, is slipped over the anodes 4 and fastened to the imperforate top of the anodes and to the outer cylindrical surface of the plug 7 by means of bands of plastic material 9. This .
~ 63~
.' .' I
Stelling i5 particlllarly easy and forms a perfect hydraulif seal between the membranes and the perrorated sections of the anodes 4 which is dirficult to obtain in conventional filter press cells.
i The cationic membrane 8 is preferably permeable to cations and impermeable to the hydrodynamic flow of the liquid and gas. Suitable materials for themembraneS are fluoridized polymers or copolymers containing sulfonic groups. Such materials are sufficiently flexible and are produced in tubular form by extrusion or hot gluing of flat sheets. The thickness of such membranes is in the order Or one-tenth of a m:illimeter.
The container 1 is turne(l 180 to facilitate fill-ing and is filled with the cathodic material 10. The I container is then closed with a rectangular plate 11 per~
forated at the base of each of the anodes 4 and, preferably,¦
Il of inert plast~c material. A rectangular brine distribution, -¦~ box 12, also Or inert plastic material, is welded to the : !i plate 11 and is closed by a closure plate 13 equipped with l a brine inlet opening 14. A ~asket may be provided between !j the plate 11 and the flanged bottom of the rectangular container 1. The flanges Or the plate 11 may be bolted to the bottom flange on container 1 and the closure plate 13 ~I may be bolted to the bottom of the distribution box 12. The I brine distribution box is connccted to the interior of the ~ i~ anodes 4 by means Or tubular connectors 15, which are 1 1l¦ flanged at one end and threaded into the threaded holes 7a ~ o~ the closure plu~s 7 e~ls or kasketk 16 aro pro~1ded ~ I , ,, , , ' !
ll between the rlanges on the connectors 15 and the brine ; distribution bo~ 12.
The cathodic compartment is filled with particulat~
material to about the top of the permeable sections 6 of the ' tubular anodes 4~
The cathodic container is provided, near the upper part, at a level higher than that Or the particulate bed 10, !
with one or more outlets 17 for hydrog~en and, in its lower part, with at least one adjustable gooseneck outlet 18 for ' i . 10 discharging the ca-tholyte.
A distribution or spray tube 24, above the level of theparticulate material 10, extends hori~ontally over sub-stantially the entire length of the container 1 and is I equippcd ~lith a series of holes so as to permit the addition l Or water or catholyte to the cathodic compartment for dilut-I ing and regulating the conccntration of the alkali metal ; I hydroxide produced in the cathode compartment.
Preferably, water is continuously added into the I cathodic compartment through the distribution tube 24, in , order to dilute the hydroxide formed at the cathode and maintain the hydroxide concentration Or the catholyte erfluer t , rrom the cell within 25% and 43% by weight.
' Each Or the tubular anodes ~1 is connected at the I top to a rectangular tank 19 extending over the entire top li f the cell container 1. The electrolyte level in the tank 19 is maintained constant by a gooseneck discharge tube 20 for the electrolyte. The electrolyte discharged rrom tube 20 , is sent to the resaturation system before being recycled !l . .
,,,,,,.. ,.,.: 11 . , ...
`` 1 3.. 3l~;~;3:~.2 . . .
!
into the cell through the elect~olyte inlet 14.
The halogen produced on the anodes separates from the electrolyte in tank 19 and escapes through outlet 21.
, The plate or cover 2 to which the tubular anodes 4 1 are welded is directly connected to the positive terminal Or the electric power supply by means o~ the connection 22 and the cathodic container 1 is connected to the negative terminal by means of connection 23.
Fig. 2 is a sectional view along the line 1-1 o~
Fig. 1, with the elements Or the cell described with refer-ence to Fig. 1 indicated by the same numerals. The locatlon o~ the distribution tube 24 is indicated by bro'~en lines ¦
above the level of the particles Or cathodic material 10 in the cathode container 1.
~i ~ The cell shown comprises six tubu]ar anodes in a rcctangular casing, but it wi]l be understood that the nunber o~ anodes may be varied in the transversè direction, j, that more rows o~ anodes may be used, that the shape of the ¦
Il cell and the anodes may be di~rerent from that illustrated 1 and that other modifications and changes May be made within ¦
the spirit and scope o~ our invention.
The extent of the cylindrical sur~aces of the tubular anodes 4 is very large relative to the volume of ;~ the container 1, which permits high production rates in !l a compact cell, at substantially equal current density ; Il' throughout the cell when compared to the cells commonly used ¦, commercially. In operation, concentrated brine (120-310 - ¦, g/ltr) o~ NaCl, ror example, is fed through the inlet 14 int I distribution b~x 12 tDd rises throu~h each ~r the tubular , .
. . , ., .
!
anodes 4, on the electrocatalytically coated surfaces of which chlorine forms. The sodium ions traverse the catlonic¦
membrane and combine with the hydroxyls released at the cathode by electrolysis of the water, forming sodlum hydr- ¦
', oxide. The chlorine rises through the electrolyte contained . j inside the tubular anodes 4 and into tank 19, where it ' separates from the liquid and escapes through the outlet 21.
The rising chlorine bubbles provide a rapid upward flow of the electrolyte in the tubes 4.
The impoverished brine flows through the constant level outlet 20 and is recycled to the resaturation system , ~r before being reintroduced into the cell through the inlet 14.' The.hydrogen released on the surfaces of the porous ,; cathode bed adjacent the rnembrane 8 rises through the 1~ paJticle bed 10 and collects in the upper space of the cathodic container, whence it escapes through the outlet 17.
The sodiurn hydroxide solution is discharged through the adjustable gooseneck 18. The adjustable gooseneck 18 .
' maintains the level.of the catholyte at substantially the n same level as the top of the cathodic bed 10.
The catholyte may be cycled through a recovery system for the sodium hydroxide located outside the cell and t4e effluent~ dilute sodium hydroxide solution,rein-troduced into the cathodic compartment through the distribu-1 tion tube 24.
11 ` . ~
Il The operat:i.ng temperature may vary between 30 and . 1000C and is pre~erably maintained at about 85C. The pH
of the anolyte may vary between 1 and 6 and the current l density may be between 1000 and 5000 ~/m2.
' While the cell and method of this invention have been described with reference to the illustrative drawings~
it is understood that numerous changes and alternati.ves may be used within the scope of this invention, that other . electrolysis processes may be carried out in the a,oparatus . described, that instead of titanium, other valve metals ; such as tantalum, ~irconium, molybdenum, niobium, tungsten and yttrium may be used in the construction ofthecell and that~
the static, conductive, particulate material may be used in other forrns of electrolysis cells.
,'' ' ~ ' .
,:
Claims (17)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. An electrolysis cell comprising an anode compartment containing an electrolyte permeable anode and a cathode compartment containing a cathode separated by an ion exchange membrane supported on the electrolyte permeable anode, means to impress an electrolysis current on the cell, means for introducing anolyte to the anode compartment, means for introducing catholyte to the cathode compartment, means for removing spent anolyte and electrolysis products from the anode compartment and means for removing spent catholyte and electrolysis products from the cathode compartment, the cathode being a porous static bed of electrically conductive catholyte-resistant particulate filling material which presses the membrane against the anode.
2. An electrolytic cell comprising a container of cathodically resistant metal, a valve metal top on said container electrically insulated from said container, at least one tubular valve metal anode connected to and extending from said top substantially to the bottom of said container, perforations through a portion of the walls of said anode inside said container and an imperforate portion of said anode extending from just below the top of said container to said valve metal top, said anode being open at both ends, an ion permeable membrane on the perforated walls of said anode, a porous, static bed of electrically conductive particulate cathodic filling material between said membrane and the walls of said container, openings into the tubular anode through the bottom of said container, means to feed electrolyte into the bottom of said tubular anode, means to electrically insulate said anode at the top and bottom from said container, means to convey positive electric current to said anode, means to convey negative electric current from said container, means to conduct gaseous products produced on said anode and electrolyte out of said container, means to conduct gaseous cathodic products produced in said container out of said container, means to introduce liquid into the cathodic compartment of said container between said membrane and the walls of said container and means to convey liquid cathodic products out of said container.
3. The cell of Claim 2 in which a plurality of anodes are connected to said valve metal top and extend substantially to the bottom of said container
4. The cell of Claim 2 in which an electrolyte tank, above said container, receives gaseous anodic products and electrolyte from said anodes, means to discharge the gaseous products from said tank and means to maintain the electrolyte level in said tank and to discharge electrolyte above said level from said tank.
5. The cell of Claim 2 in which said membranes are fastened to the tops and bottoms of said anodes by bands of plastic material.
6. The cell of Claim 3 in which the porous, static bed of particulate filling material in said container is from the group consisting of graphite, lead, iron, nickel, cobalt, vanadium, molybdenum, zinc, and alloys thereof, inter-metallic compounds and compounds of hydridization, carbidization and nitroidization of metals.
7. An electrolysis cell comprising a cathodic container, a valve metal cover for said container, a plurality of tubular valve metal anodes with walls permeable to liquids inside said container and secured to the cover of said container, tubular ion exchange membranes on the outer surfaces of said tubular anodes delimiting and hydraulically separating the cathodic compartment inside said container from the anodic compartment inside said tubular anodes, a bottom closure for said container means in said closure forming hydraulic connection between the interior of said tubular anodes and an electrolyte, distributor external to the cathodic container, a static, porous bed of conductive particulate filling material resistant to the cathodic conditions in said cathodic container to a height just below the cover of the container, pressing said membranes against said anodes, said static, porous bed being in electrical contact with the inner walls of the cathodic container and functioning as the cathodic at the surface adjacent to said membranes, a tank for receiving impoverished electrolyte and anodic gas connected with the upper ends of said tubular anodes, means for passing electrolysis current between said anodes and the cathodic of the cell and means for recovering gaseous and liquid products from the cathodic compartment.
8. The cell of Claim 7 in which the tubular membranes are permeable to the cations and impermeable to the hydraulic flow of gases and liquids.
9. The cell of Claim 8 in which the membrane comprises a fluoridized polymer or copolymer having sulfonic groups.
10. The cell of Claim 7 in which the tubular anodes are formed of valve metal coated with an electrocatalytic deposit.
11. The cell of Claim 7 in which the inner walls of the cathodic container consist of a material from the group containing iron, nickel and alloys thereof.
12. The cell of Claim 7 in which said static, porous bed of particulate filling material from the group of graphite, lead, iron, nickel, cobalt, vanadium, molybdenum, zinc and alloys thereof, and compounds of hydridization, carbidization and nitridization of said materials, extends between the walls of said cathodic container and the membranes on the outer surfaces of said anodes.
13. The cell of Claim 12 in which the static, porous bed comprises fragments in the form of balls, beads, saddles, Raschig rings, cylinders, chips and metal wool.
14. The method of reducing the interelectrode gap in an electrolysis cell having an anode compartment, a cathode compartment, a porous and permeable anode in the anode compartment and a cathode in the cathode compartment, an ion exchange membrane between the anode and the cathode compartment and means to pass an electrolysis current through said cell, which comprises pressing said membrane against said porous anode surface by a porous, static bed of conducting particulate filling material between the walls of said cathode compartment and said membrane and conducting electric current through said anode, said membrane and said particulate filling material between said membrane and the walls of said cathode compartment.
15. In an electrolysis cell having an anode compartment and a cathode compartment, electrodes comprising an anode and a cathode, means to pass an electrolysis current between said anode and said cathode and an ion exchange membrane between said electrodes, the method of reducing the interelectrodic gap to approximately the thickness of said membrane, which comprises placing said membrane against one of said electrodes, pressing said membrane against said electrode by a porous, static bed of conducting particulate filling material between said membrane and the other electrode, and passing the electrolysis current between said electrodes through said static bed.
16. In an electrolytic cell having electrocatalytically coated valve metal anodes, a cathode and ion selective cationic membranes substantially impermeable to the flow of liquids and gases therethrough, between the anodes and cathodes, the method of maintaining the current density substantially constant and of reducing mechanical and electrical stresses on said membranes which comprises applying said membranes on said anodes, substantially filling the space between the membranes and the electrically conducting walls of the cathodes with, porous cathodic filling material in the form of chips, balls, beads, cylinders, Raschig rings, metallic wool or other particles or strands pressing said membranes against said anodes, passing an electrolysis current from said anodes through said membranes and said filling material to the electrically conducting walls of said cathodes and collecting the anodic gases and liquids separate from the cathodic gases and liquids.
17. The method of Claim 16 in which the cathodic filling material is from the group consisting of graphite, lead, iron, nickel, cobalt, vanadium, molybdenum, zinc, and alloys thereof, intermetallic compounds, and compounds of hydridization, carbidization and nitridization of metals.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| IT25,251A/77 | 1977-06-30 | ||
| IT25251/77A IT1114820B (en) | 1977-06-30 | 1977-06-30 | ELECTROLYTIC MONOPOLAR MEMBRANE CELL |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1106312A true CA1106312A (en) | 1981-08-04 |
Family
ID=11216133
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA306,441A Expired CA1106312A (en) | 1977-06-30 | 1978-06-28 | Electrolytic cell with membrane |
Country Status (9)
| Country | Link |
|---|---|
| JP (4) | JPS58756B2 (en) |
| CA (1) | CA1106312A (en) |
| DE (1) | DE2828621A1 (en) |
| GB (1) | GB2002032B (en) |
| IT (1) | IT1114820B (en) |
| NL (1) | NL179926C (en) |
| SE (3) | SE446104B (en) |
| SU (1) | SU1286109A3 (en) |
| UA (1) | UA6325A1 (en) |
Families Citing this family (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| IT1114820B (en) * | 1977-06-30 | 1986-01-27 | Oronzio De Nora Impianti | ELECTROLYTIC MONOPOLAR MEMBRANE CELL |
| US4298447A (en) * | 1980-03-07 | 1981-11-03 | E. I. Du Pont De Nemours And Company | Cathode and cell for lowering hydrogen overvoltage in a chlor-akali cell |
| US4337127A (en) * | 1980-03-07 | 1982-06-29 | E. I. Du Pont De Nemours And Company | Method for making a cathode, and method for lowering hydrogen overvoltage in a chlor-alkali cell |
| JPS5941484A (en) * | 1982-08-30 | 1984-03-07 | Toagosei Chem Ind Co Ltd | Electrolytic tank for electrolysis of aqueous alkali chloride solution |
| JPS59164976A (en) * | 1983-03-10 | 1984-09-18 | Fuji Electric Corp Res & Dev Ltd | Tritium concentration measurement method |
| JPS6241530U (en) * | 1985-08-29 | 1987-03-12 | ||
| JPS62284095A (en) * | 1986-06-02 | 1987-12-09 | Permelec Electrode Ltd | Durable electrolytic electrode and its production |
| JPH01201225A (en) * | 1988-02-04 | 1989-08-14 | Nippon Patent Electric Kk | Floor surface grinder |
| JPH0611227U (en) * | 1992-07-15 | 1994-02-10 | 東海ゴム工業株式会社 | Metal laminated sheath cable |
| US9962404B2 (en) | 2012-09-21 | 2018-05-08 | Reoxcyn Innovation Group, Llc | Cell for electrolyzing a liquid |
Family Cites Families (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1194181A (en) * | 1966-05-24 | 1970-06-10 | Nat Res Dev | Improvements relating to Electrode Arrangements for Electrochemical Cells. |
| US3674676A (en) * | 1970-02-26 | 1972-07-04 | Diamond Shamrock Corp | Expandable electrodes |
| DE2244244C3 (en) * | 1972-09-15 | 1981-07-02 | Dart Industries Inc., 90048 Los Angeles, Calif. | Electrolytic process for removing a contaminant dissolved in an aqueous spent solution and regenerative electrolytic cell which can be used for this purpose |
| GB1423369A (en) * | 1973-09-24 | 1976-02-04 | Electricity Council | Electrolytic cells |
| DE2503652A1 (en) * | 1974-02-04 | 1975-08-07 | Diamond Shamrock Corp | CELL FOR CHLORAL CALCIUM ELECTROLYSIS |
| GB1497542A (en) * | 1974-05-30 | 1978-01-12 | Parel Sa | Electrochemical apparatus |
| US3969201A (en) * | 1975-01-13 | 1976-07-13 | Canadian Patents And Development Limited | Electrolytic production of alkaline peroxide solutions |
| US3984303A (en) * | 1975-07-02 | 1976-10-05 | Diamond Shamrock Corporation | Membrane electrolytic cell with concentric electrodes |
| IT1114820B (en) * | 1977-06-30 | 1986-01-27 | Oronzio De Nora Impianti | ELECTROLYTIC MONOPOLAR MEMBRANE CELL |
-
1977
- 1977-06-30 IT IT25251/77A patent/IT1114820B/en active
-
1978
- 1978-05-24 SE SE7805927A patent/SE446104B/en not_active IP Right Cessation
- 1978-06-19 JP JP53073311A patent/JPS58756B2/en not_active Expired
- 1978-06-27 GB GB7827988A patent/GB2002032B/en not_active Expired
- 1978-06-28 CA CA306,441A patent/CA1106312A/en not_active Expired
- 1978-06-29 NL NLAANVRAGE7807036,A patent/NL179926C/en not_active IP Right Cessation
- 1978-06-29 SU SU782633304A patent/SU1286109A3/en active
- 1978-06-29 DE DE19782828621 patent/DE2828621A1/en active Granted
- 1978-06-29 UA UA2633304A patent/UA6325A1/en unknown
-
1981
- 1981-12-18 JP JP56203825A patent/JPS57126984A/en active Granted
-
1982
- 1982-09-20 SE SE8205353A patent/SE445471B/en not_active IP Right Cessation
- 1982-12-14 SE SE8207131A patent/SE445562B/en not_active IP Right Cessation
-
1984
- 1984-03-29 JP JP59062083A patent/JPS6053115B2/en not_active Expired
- 1984-03-29 JP JP59062084A patent/JPS6036683A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| SE8207131D0 (en) | 1982-12-14 |
| NL7807036A (en) | 1979-01-03 |
| JPS5417375A (en) | 1979-02-08 |
| NL179926B (en) | 1986-07-01 |
| IT1114820B (en) | 1986-01-27 |
| GB2002032A (en) | 1979-02-14 |
| DE2828621A1 (en) | 1979-01-11 |
| JPH0153355B2 (en) | 1989-11-14 |
| SE445562B (en) | 1986-06-30 |
| SE8205353D0 (en) | 1982-09-20 |
| JPH0124867B2 (en) | 1989-05-15 |
| GB2002032B (en) | 1982-07-14 |
| SE446104B (en) | 1986-08-11 |
| NL179926C (en) | 1986-12-01 |
| SE8205353L (en) | 1982-09-20 |
| UA6325A1 (en) | 1994-12-29 |
| SE445471B (en) | 1986-06-23 |
| SE8207131L (en) | 1982-12-14 |
| JPS58756B2 (en) | 1983-01-07 |
| JPS59182984A (en) | 1984-10-17 |
| DE2828621C2 (en) | 1989-11-09 |
| JPS57126984A (en) | 1982-08-06 |
| JPS6053115B2 (en) | 1985-11-22 |
| SU1286109A3 (en) | 1987-01-23 |
| SE7805927L (en) | 1978-12-31 |
| JPS6036683A (en) | 1985-02-25 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |