This application claims priority to European application No. 13162063.5 filed on April 3, 2013, the whole content of this application being incorporated herein by reference for all purposes.

The present invention relates to a plant for chlor-alkali electrolysis.

Plants for chlor-alkali electrolysis are well known. They are constructed from equipment parts that are assembled on the production site. Those plants are dedicated to the manufacture of high volumes of specific products. They are designed for operation with specific raw materials. Such plants exhibit low if not nil flexibility in process conditions, part arrangements and/or raw materials selection.

The object of the present invention is to provide a chlor-alkali electrolysis plant which does not present these drawbacks.

The invention therefore relates in a first embodiment to a mobile/movable chlor-alkali electrolysis plant comprising at least one chlor-alkali electrolysis module, said chlor-alkali electrolysis module comprising at least one

electrolyzer, wherein the electrolyzer contains at least two different separator- electrodes assemblies.

In the following part of the description and for the sake of conciseness, a separator-electrodes assembly will be abbreviated as a SEA.

One of the important features of the chlor-alkali electrolysis plant according to the invention is that the chlor-alkali electrolysis module contains at least two different SEAs. This has the advantages of:

■ allowing the simultaneous evaluation of the performances of several SEAs and of their constituting parts with respect to raw materials, and/or electrolysis process conditions,

■ allowing a rapid determination of the compatibility of the SEAs with the electrolyte, used in the electrolysis process,

■ permitting a rapid identification of the best SEA for manufacturing the electrolysis product and,

■ leading to a concomitant gain in time evaluation. The movable chlor-alkali electrolysis plant according to the invention is named indifferently movable chlor-alkali electrolysis plant or chlor-alkali electrolysis plant or electrolysis plant in the text of the present application.

The electrolysis plant according to the invention is preferably a plant for the production of chlorine, more preferably a plant for the production of chlorine by electrolysis of brine and most preferably a chlor-alkali membrane electrolysis plant for the production of chlorine.

In the electrolysis plant according to the invention, the electrolyzer can be of any type. The electrolyser can be mono-polar or bi-polar. It is preferably bi- polar.

In the electrolysis plant according to the invention, the separator of the two different separator-electrodes assemblies can be of any type. The separator is preferably a diaphragm or a membrane and more preferably a membrane.

In the electrolysis plant according to the invention, the two separators of the two different separator-electrodes assemblies can be both a diaphragm or a membrane or are one diaphragm and one membrane.

In the electrolysis plant according to the invention, the two separator- electrode assemblies can differ from each other by at least one of the following features:

■ They contain a different separator;

■ They contain a different membrane;

■ They contain a different diaphragm;

■ They contain a different anode;

■ They contain a different cathode.

In the electrolysis plant according to the invention, the electrolyser contains at least two different separator-electrode assemblies and preferably the two separators of the two different separator-electrode assemblies are both a diaphragm or a membrane or are one diaphragm and one membrane, and the two separator-electrode assemblies differ from each other by at least one of the following features:

■ They contain a different separator

■ They contain a different membrane,

■ They contain a different diaphragm,

■ They contain a different anode,

■ They contain a different cathode. In a first preferred aspect of the first embodiment, the electrolyser is a bipolar electrolyser which comprises at least two stacked membrane-electrodes assemblies with two different membranes, two identical anodes and two identical cathodes.

In a second preferred aspect of the first embodiment, the electrolyser is a bipolar electrolyser which comprises at least two stacked membrane-electrodes assemblies with two identical membranes, two different anodes and two identical cathodes.

In a third preferred aspect of the first embodiment, the electrolyser is a bipolar electrolyser which comprises at least two stacked membrane-electrodes assemblies with two identical membranes, two identical anodes and two different cathodes.

In a fourth preferred aspect of the first embodiment, the electrolyser is a bipolar electrolyser which comprises three stacked membrane-electrodes assemblies with three different membranes, three identical anodes and three identical cathodes.

In the electrolysis plant according to the invention, the anodes of the SEAs usually comprise at least one metallic support and at least one electroactive coating applied on that metallic support and differ from each other by at least one of the following features:

■ They contain a different metal for the metallic support;

■ The metallic supports have a different form;

■ They have a different electroactive coating;

■ They have a different design.

In the electrolysis plant according to the invention, the anodes of the SEAs preferably exhibit the above features.

The metal of the metallic support can be of any type. The person of ordinary skill in the art can select that metal depending on the raw materials to be electrolysed and/or the type of separator in the SEA. The metal of the metallic support exhibits usually a good electrical conductivity.

When the raw material to be electrolysed is a brine, the metal of the metallic support is preferably titanium. In that case, the metallic support can be provided in any form, such as a sheet, a plate or a mesh.

The electroactive coating can be of any type. The person of ordinary skill in the art can select the electroactive coating depending on the raw materials to be electrolysed. The electroactive coating usually allows the conversion of the raw materials into the desired product with a low overpotential.

When the raw material to be electrolysed is a brine, the electroactive coating is usually selected from ruthenium oxide coatings, more preferably containing ruthenium oxide as basic component along with an oxide of a non- platinum metal (e.g. Ti, Sn or Zr), and optionally a second precious metal oxide selected from the group of Pt and Ir.

The design of the anode can be of any type. The person of ordinary skill in the art can select the anode design depending on the raw materials to be electrolysed and/or the type of separator in the SEA.

When the raw material to be electrolysed is a brine, the anode design is usually selected from anode mesh designs.

Examples of anodes are described in T.F O'Brien, T. Bommaraju and F. Hine, Handbook of Chlor-Alkali Technology, Springer, 2005, pages 211-237.

In the electrolysis plant according to the invention, the cathodes of the

SEAs usually comprise at least one metallic support and at least one electroactive coating applied on that metallic support and differ from each other by at least one of the following features:

■ They contain a different metal for the metallic support;

■ The metallic supports have a different form;

■ They have a different electroactive coating;

■ They have a different design.

In the electrolysis plant according to the invention, the cathodes of the SEAs preferably exhibit the above features.

The metal of the metallic support can be of any type. The person of ordinary skill in the art can select the metal of the metallic support depending on the raw materials to be electrolysed and/or the type of separator in the SEA. The metal of the metallic support exhibits usually a good electrical conductivity. When the raw material to be electrolysed is a brine or a caustic soda solution, that metal is preferably nickel. In that case, the metal of the metallic support can be provided in any form, such as a sheet, a plate or a mesh.

The electroactive coating can be of any type. The person of ordinary skill in the art can select the electroactive coating depending on the raw materials to be electrolysed. The electroactive coating usually allows the conversion of the raw materials into the desired product with a low overpotential. When the raw materials to be electrolysed is a brine or a caustic soda solution , the electroactive coating is usually selected from ruthenium oxide coatings, containing more preferably ruthenium oxide and optionally a second precious metal selected from the group of Pt and Pd.

The design of the cathode can be of any type. The person of ordinary skill in the art can select the cathode design depending on the raw materials to be electrolysed and/or the type of separator in the SEA.

When the raw material to be electrolysed is a brine, the cathode design is usually selected from mesh cathode designs.

Examples of cathodes are described in Handbook of Chlor-alkali

Technology, Springer, 2005, pages 241-265.

In the electrolysis plant according to the invention, when the separator of the SEA is a diaphragm, the diaphragm can be of any type. The diaphragm is preferably selected from a polymer- inorganic compounds based diaphragm or an asbestos based diaphragm. The diaphragms are preferably as described in

Handbook of Chlor-Alkali Technology, Springer, 2005, pages 272-273 and 292- 294. An example of polymer-based diaphragms are Polyramix™ (PMX) diaphragms. An example of asbestos-based diaphragms are chrysotile based diaphragms.

In the electrolysis plant according to the invention, when the separator or the SEA is a diaphragm, at least one of the two different diaphragms is preferably selected from an asbestos base diaphragm and a polymer based diaphragm.

In the electrolysis plant according to the invention, when the separator of the SEA is a membrane, the membrane can be of any type. The membrane is preferably an ion-exchange membrane, preferably a cation-exchange membrane. The cation exchange membrane is preferably based on a perfluoropolymer containing sulfonic and/or carboxylic groups, more preferably sulfonic and carboxylic groups. The membranes are preferably as described in Handbook of Chlor-Alkali Technology, Springer, 2005, pages 306-307. Examples of membranes are N2030 and N2040 from DuPont, F6805 from Asahi Chemicals, F 8020SP and F 8080, F8081, F8080HD and F8081HD from Asahi Glass.

Membranes N2040 from DuPont, F6805 from Asahi Chemicals and F 8080 from Asahi Glass are particularly convenient. In the electrolysis plant according to the invention, when the separator of the SEA is a membrane, at least one of the two different membranes is preferably selected from a F8080 membrane, a N2040 and a F6805 membrane.

In the electrolysis plant according to the invention, the electrolyser has usually a width higher than or equal to 0.1 m, preferably higher than or equal to 0.2 m and most preferably higher than or equal to 0.3 m. This width is usually lower than or equal to 1 m, preferably lower than or equal to 0.8 m and most preferably lower than or equal to 0.5 m. The electrolyser has usually a height higher than or equal to 0.8 m, preferably higher than or equal to 1 m and most preferably higher than or equal to 1.25 m. This height is usually lower than or equal to 2 m, preferably lower than or equal to 1.8 m and most preferably lower than or equal to 1.7 m. The electrolyser has usually a thickness higher than or equal to 0.1 m, preferably higher than or equal to 0.25 m and most preferably higher than or equal to 0.3 m. This thickness is usually lower than or equal to 0.8 m, preferably lower than or equal to 0.7 m and most preferably lower than or equal to 0.6 m.

In the electrolysis plant according to the invention, when the separator in the electrolyser is a membrane, the membrane has usually a geometric area higher than or equal to 0.01 m ² , preferably higher than or equal to 0.05 m ² and most preferably higher than or equal to 0.1 m ² . This area is usually lower than or equal to 1 m ² , preferably lower than or equal to 0.50 m ² and most preferably lower than or equal to 0.20 m ² . A membrane with a geometric area of about 0.15 m ² is particularly convenient. The membrane can be of any geometric form. A rectangular membrane is preferred.

In the electrolysis plant according to the invention, the electrolyser is preferably a bipolar chlor-alkali electrolyser containing three different membranes with an individual active surface of about 0.15 m ² , composed by two bipolar elements and two half-cell extremity elements. By active surface, one intends to mean the surface of the membrane which is contact with the electrolyte. The anodic compartment of the electrolyser is preferably fed with a brine. This configuration permits to test three different membranes with the same feeding brine. In this case, the electrolysis plant is well suited for chlorine production.

In the electrolysis plant according to the invention, the electrolyser is preferably equipped with one or more sensors for monitoring independently one or more parameters such as temperature, pressure, voltage, electrolyte composition or current of each separator-electrodes assembly.

The sensors are preferably being interconnected with one or more first computers. The first computers are preferably being linked to one or more second computers in a control room via a communication network. The control room can be close or remote from the electrolysis plant. It is preferably close to the electrolysis plant.

Said first computer(s) is/are (a) computer(s) which take(s) care of the control and safeguarding of the electrolysis plant. Preferably, said first computer(s) is/are placed in close proximity of the electrolysis plant, i.e. in the same location as the plant. Said second computer(s), via which the plant parameters can be analyzed and monitored and the plant according to the present invention controlled, preferably by one or more qualified operators, preferably chlorine operators, is/are placed in a control room which is remote from the plant. The control room can be remote from the electrolysis plant, but still on the same production site as the plant. The control room can also be at a different site which can be located in the same country, but also in another country or even on another continent. The communication network through which the first and second computer(s) are linked can for instance be the Internet. Alternatively, the communication network can be an extranet or an intranet.

Said sensors on said electrolysers are part of a monitoring system conventionally used in the art for monitoring the performance of an electrolysis plant. A suitable monitoring system has, for instance, been described in US 6,591,199.

In the electrolysis plant according to the invention, the electrolysis module preferably contains at least one electrical current rectifier, and/or at least one tank for an electrolyte, preferably at least one tank for storing an anolyte and/or at least one tank for storing a catholyte.

One important feature of the electrolysis plant according to the invention is that it is mobile or expressed in a better way movable. By mobile/movable, one intends to denote that the plant can be transported from one site to another one with minimal handling, i.e. minimal amount of dismantling/assembling operations.

In a second embodiment, the invention relates to a mobile/movable chlor- alkali electrolysis plant comprising at least one chlor-alkali electrolysis module, said electrolysis module comprising at least one electrolyzer, wherein the electrolyzer contains at least two different separator-electrodes assemblies, wherein the electrolyser contains one electrolyte, and wherein the electrolysis module is preferably mounted on a first support which can be moved as a whole. The electrolysis plant preferably comprises in addition at least one module for a treatment of the electrolyte mounted on a second support which can be moved as a whole.

By as a whole, it is intended to mean that a minimal dismantling of the electrolysis module or of the treatment module is needed, before moving the electrolysis plant. By minimal dismantling, it is intended to mean that at most 10 % by weight, preferably at most 5 % by weight, more preferably at most 1 % by weight of the electrolysis module mounted on the support or of the module for the treatment of the electrolyte mounted on the support, is dismantled before moving the plant.

In the movable electrolysis plant according to the invention, the first support and the second support can be distinct or can be the same. It is preferred that the first support and the second support are distinct.

In the movable electrolysis plant according to the invention, the support can be of any type. This support must be resistant enough to accommodate the weight of the module. It must be rigid enough to be moved when moved with the module. The support is preferably a metallic support. The support is more preferably a container or a platform. First and second supports are therefore more preferably a container or a platform. Examples of platforms are platforms constituted by a basis only or those comprising further a vertical axis on each of the four corner.

In case the first support and the second support are distinct, one of them can be a container and the other a platform, both of them can be a container or both of them can be a platform.

The support mounted module is more preferably assembled in a container, preferably a standardized-size container, or on a platform, preferably a standard- size platform. The support mounted module is most preferably assembled in a container, preferably a standardized-size container.

The module is therefore advantageously easily transported by transporting the container with its content or the platform with its content.

Transportation can be by road, by rail, by air, by sea, or by any

combination thereof. Transportation is preferably by road since industrial sites are more easily accessible by road than by any other transportation means. The other means like by air, by sea or by rail, can however be envisioned at least for part of the transportation itinerary which is intermediate between the sites.

The movable electrolysis plant according to the invention can therefore be transported with a truck and discharged from the truck with usual mechanical means. An example of usual mechanical means is a fork-lift truck. Another example is a crane.

In the movable electrolysis plant according to the invention, the support has advantageously dimensions adapted to transportation.

Standard-size containers can be of any type. Standard-size platforms can be of any type. Such types are for example as disclosed in International Standard ISO 6346 managed by the International Container Bureau.

Standard-size containers are preferably selected from Standard 20', upgraded 20', Standard 40', High Cube 40', Open Top 20', Open Top 40', Reefer 20', Reefer 40', Reefer High Cube 40', Flat Rack 20', Flat Rack 40', Flat Rack Collapsible 20' or Flat rack Collapsible 40', which characteristics are disclosed in http://www.foreign-trade.com/reference/ocean.cfm.

Standard-size platforms are preferably selected from Platform 20', Platform 40', Chassis 23'6", Chassis 33' Tri-axle or Chassis 40' Gooseneck, which characteristics are disclosed at http ://www. foreign- trade . com/reference/ocean . cfm.

The movable electrolysis plant according to the invention is therefore advantageously not a plant deposited in a metallic frame or in a container or on a platform for transportation and separated from it for being used.

In the movable electrolysis plant according to the invention, the support mounted electrolysis module usually exhibits an external envelope having a length lower than or equal to 12.50 m, a width lower than or equal to 2.50 m and a height lower than or equal to 3.50 m. The the support mounted electrolysis module has usually a weight lower than or equal to 40000 kg.

In the movable electrolysis plant according to the invention, the support mounted module for a treatment of the electrolyte, usually exhibits an external envelope having a length lower than or equal to 12.50 m, a width lower than or equal to 2.50 m and a height lower than or equal to 3.50 m. The support mounted module for a treatment of the electrolyte has usually a weight lower than or equal to 40000 kg. By external envelope, one intends to mean the minimal parallelepiped volume which can contain the support mounted electrolysis module or the support mounted module for a treatment of the electrolyte.

In the movable electrolysis plant according to the invention, both the support mounted electrolysis module and the support mounted module for a treatment of the electrolyte when present, exhibit an external envelope as mentioned here above.

The support mounted electrolysis module and/or the support mounted module for a treatment of the electrolyte preferably exhibits at least one of the fo llo wing features :

■ an external envelope having a length lower than or equal to 5.89 m, a width lower than or equal to 2.33 m, a height lower than or equal to 2.38 m, preferably lower than or equal to 2.28 m and a weight lower than or equal to 21727 kg;

- an external envelope having a length lower than or equal to 5.89 m, a width lower than or equal to 2.31 m, preferably lower than or equal to 2.28 m, a height lower than or equal to 2.38 m, preferably lower than or equal to 2.28 m and a weight lower than or equal to 28120 kg.

■ an external envelope having a length lower than or equal to 12.01 m, a width lower than or equal to 2.33 m, preferably lower than or equal to 2.28 m, a height lower than or equal to 2.38 m, preferably lower than or equal to 2.28 m and a weight lower than or equal to 26780 kg.

■ an external envelope having a length lower than or equal to 12.01 m, a width lower than or equal to 2.33 m, a height lower than or equal to 2.69 m, preferably lower than or equal to 2.56 m and a weight lower than or equal to 26512 kg;

■ an external envelope having a length lower than or equal to 5.89 m, a width lower than or equal to 2.31 m, preferably lower than or equal to 2.28 m, a height lower than or equal to 2.33 m, preferably lower than or equal to 2.18 m and a weight lower than or equal to 21600 kg;

■ an external envelope having a length lower than or equal to 12.01 m, a width lower than or equal to 2.33 m, a height lower than or equal to 2.33 m, preferably lower than or equal to 2.26 m and a weight lower than or equal to 26630 kg;

■ an external envelope having a length lower than or equal to 5.38 m, a width lower than or equal to 2.26 m, a height lower than or equal to 2.26 m, preferably lower than or equal to 2.20 m and a weight lower than or equal to 20756 kg;

■ an external envelope having a length lower than or equal to 11.48 m, a width lower than or equal to 2.2.26 , a height lower than or equal to 2.18 m, preferably lower than or equal to 2.13 m and a weight lower than or equal to 25526 kg;

■ an external envelope having a length lower than or equal to 11.35 m, a width lower than or equal to 2.28 m, a height lower than or equal to 2.48 m, preferably lower than or equal to 2.43 m and a weight lower than or equal to 28120 kg;

■ an external envelope having a length lower than or equal to 5.61 m, a width lower than or equal to 2.20 m, a height lower than or equal to 2.23 m and a weight lower than or equal to 27722 kg;

■ an external envelope having a length lower than or equal to 12.06 m, a width lower than or equal to 2.08 m, a height lower than or equal to 1.95 m and a weight lower than or equal to 38918 kg;

■ an external envelope having a length lower than or equal to 5.63 m, a width lower than or equal to 2.20 m, a height lower than or equal to 2.23 m and a weight lower than or equal to 27722 kg;

■ an external envelope having a length lower than or equal to 12.06 m, a width lower than or equal to 2.08 m, a height lower than or equal to 1.95 m and a weight lower than or equal to38918 kg;

■ an external envelope having a length lower than or equal to 6.07 m, a width lower than or equal to 2.43 m, a height lower than or equal to 2.23 m and a weight lower than or equal to 23993 kg;

■ an external envelope having a length lower than or equal to 12.19 m, a width lower than or equal to 2.43 m, a height lower than or equal to 1.95 m and a weight lower than or equal to 30117 kg;

■ an external envelope having a length lower than or equal to 8.25 m and a weight lower than or equal to 17955 kg;

■ an external envelope having a length lower than or equal to 12.7 m and a weight lower than or equal to 20227 kg;

■ an external envelope having a length lower than or equal to 9.97 m and a weight lower than or equal to 17955 kg;

- an external envelope having a length lower than or equal to 12 m and a weight lower than or equal to 20227 kg. The movable electrolysis plant according to the invention is

advantageously built as follows: the support mounted electrolysis module and the support mounted module for a treatment of the electrolyte are advantageouly assembled in the same container or in separate containers on a first site, and transported, preferably by road, to a second site.

The movable electrolysis plant according to the invention is preferably built as follows: the support mounted electrolysis module and the support mounted module for a treatment of the electrolyte are preferably assembled in separate containers on a first site and transported, preferably by road, to a second site.

In the electrolysis plant according to the invention, when the electrolyte is a brine, and when the electrolysis plant comprises a module for a treatment of the electrolyte, the module for a treatment of the brine preferably comprises at least one unit selected from a unit for adjusting the salt concentration of the brine at least by salt addition to the brine, a unit for removing fine solid particles from the brine at least by filtration, a unit for removing carbonate ions from the brine at least by acidification and venting, a unit for removing iron and aluminium from the brine at least by filtration, a unit for removing calcium and magnesium from the brine at least by ion-exchange, a unit for removing chlorine from the brine at least by acidification, stripping and adsorption, a unit for removing iodine from the brine at least by oxidation and ion exchange, a unit for removing bromine from the brine at least by oxidation, a unit for removing silicon from the brine at least by precipitation and filtration, a unit for removing chlorate from the brine at least by acidification or catalytic hydrogenation, a unit for removing sulphate from the brine at least by precipitation and filtration or by nano filtration with membranes, a unit for removing organic compounds from the brine at least by oxidation, a unit for removing mercury from the brine at least by precipitation, ion-exchange reduction or adsorption, and a unit for removing ammonia from the brine at least by oxidation and venting.

Those units are such as described in patent application filed the same day as the present application in the name of SOLVAY S.A., entitled "Plant for chlor-alkali electrolysis and a process for using it", the entire content of which is herein incorporated by reference.

In the electrolysis plant according to the invention, when the electrolyte is a brine, and when the electrolysis plant comprises a module for a treatment of the electrolyte, the electrolysis module and the module for a treatment of the brine are preferably equipped with one or more sensors for monitoring one or more parameters such as temperature, pressure, voltage, current, flow rate, electrolyte composition or fluid level. Said sensors are preferably interconnected with one or more first computers. Said first computers are preferably linked to one or more second computers in a control room via a communication network. Said control room is preferably remote from the movable electrolysis unit.

In a third embodiment, the invention relates to an electrolysis plant comprising at least one electrolysis module, said electrolysis module comprising at least one electrolyzer, wherein the electrolyzer contains at least two different separator-electrodes assemblies and wherein the electrolysis plant is preferably for electrolysis of a brine into a depleted brine. More preferably, it contains at least two different modules for the treatment of the brine and/or of the depleted brine. Still more preferably, the electrolysis module and the treatment modules are connected to each other allowing that the operation of the plant can be started with only one treatment module or with any combination of two or more treatment modules, and that at any time one of the treatments can be switched off and/or an additional treatment can be added, and/or the order of the treatments can be modified.

In a fourth embodiment, the invention is related to the use of an electrolysis plant comprising at least one electrolysis module, said electrolysis module comprising at least one electrolyzer, wherein the electrolyzer contains at least two different separator-electrodes assemblies electrolysis, for chlorine

production.

In a fifth embodiment, the invention is related to a process for chlorine production comprising electrolyzing a brine in the electrolysis module of an electrolysis plant comprising at least one electrolysis module, said electrolysis module comprising at least one electrolyzer, wherein the electrolyzer contains at least two different separator-electrodes assemblies, wherein the brine is selected from a depleted brine from an industrial process for manufacturing gaseous chlorine, a brine from an epoxide manufacturing process, preferably ethylene oxide, propylene oxide, butylene oxide or epichlorohydrin, and more preferably epichlorohydrin, a brine from an epoxide derivative manufacturing process, preferably epoxy resin, a brine from a process for manufacturing a chlorinated organic product, preferably 1 ,2-dichloroethane or 1 ,2-dichloroethylene, and more preferably 1 ,2-dichloroethane, a brine from a process for manufacturing a monoisocyanate or a polyisocyanate, preferably 4,4'-methylenediphenyl diisocyanate (MDI), toluene diisocyanate (TDI) or hexamethylene-1,6- diisocyanate (HDI), a brine from a process for manufacturing a polycarbonate, preferably 2,2-bis(4-hydroxyphenyl)propane polycarbonate (bisphenol A polycarbonate), and any mixture thereof.

In a sixth embodiment, the invention is related to a process for chlorine production comprising electrolyzing a brine into a depleted brine in the electrolysis module of an electrolysis plant comprising at least one electrolysis module, said electrolysis module comprising at least one electrolyzer, wherein the electrolyzer contains at least two different separator-electrodes assemblies, the process comprising subjecting the brine to at least one first treatment in order to obtain a treated brine, feeding at least one first vessel intermittently with the treated brine, feeding the at least one electrolyser continuously with the treated brine from said first vessel in order to obtain the depleted brine, and withdrawing continuously the depleted brine from said electrolyser.

Should the disclosure of any patents, patent applications, and publications which are incorporated herein by reference conflict with the description of the present application to the extent that it may render a term unclear, the present description shall take precedence.