EP1442158A2 - Electrochemical half cell - Google Patents

Electrochemical half cell

Info

Publication number
EP1442158A2
EP1442158A2 EP02785267A EP02785267A EP1442158A2 EP 1442158 A2 EP1442158 A2 EP 1442158A2 EP 02785267 A EP02785267 A EP 02785267A EP 02785267 A EP02785267 A EP 02785267A EP 1442158 A2 EP1442158 A2 EP 1442158A2
Authority
EP
European Patent Office
Prior art keywords
gas
electrolyte
connecting channel
retaining element
pocket
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.)
Withdrawn
Application number
EP02785267A
Other languages
German (de)
French (fr)
Inventor
Hans-Dieter Pinter
Andreas Bulan
Walter Klesper
Fritz Gestermann
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Covestro Deutschland AG
Original Assignee
Bayer MaterialScience AG
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Bayer MaterialScience AG filed Critical Bayer MaterialScience AG
Publication of EP1442158A2 publication Critical patent/EP1442158A2/en
Withdrawn legal-status Critical Current

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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
    • C25B15/00—Operating or servicing cells
    • C25B15/08—Supplying or removing reactants or electrolytes; Regeneration of electrolytes
    • 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
    • C25B1/24—Halogens or compounds thereof
    • C25B1/26—Chlorine; Compounds 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
    • 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
    • C25B11/00—Electrodes; Manufacture thereof not otherwise provided for
    • C25B11/02—Electrodes; Manufacture thereof not otherwise provided for characterised by shape or form
    • C25B11/03—Electrodes; Manufacture thereof not otherwise provided for characterised by shape or form perforated or foraminous
    • C25B11/031—Porous electrodes
    • 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
    • C25B9/17—Cells comprising dimensionally-stable non-movable electrodes; Assemblies of constructional parts thereof
    • C25B9/19—Cells comprising dimensionally-stable non-movable electrodes; Assemblies of constructional parts thereof with diaphragms

Definitions

  • the invention relates to an electrochemical half cell which is particularly suitable for the electrochemical production of chlorine from aqueous solutions of an alkali metal chloride by means of a gas diffusion electrode.
  • DE 196 22 744 describes an electrolysis cell for the production of chlorine and sodium hydroxide solution by electrolysis using gas diffusion electrodes when using pressure compensation between the height-dependent pressure of the sodium hydroxide solution before
  • Gas diffusion electrode and the constant pressure of the oxygen behind the gas diffusion electrode and the passage of oxygen through gas pockets known.
  • the gas diffusion electrode is operated as an oxygen consumption cathode.
  • the gas diffusion electrode is an open-pore membrane. This is between electrolyte and
  • the . Gas diffusion electrode can e.g. be prepared by the method described in DE-A-37 10 168. However, the tightness of the gas diffusion electrode is only present up to a finite pressure drop between the gas side and the liquid side. Is the
  • DE 196 22 744 proposes dividing the gas space into several gas pockets.
  • the electrochemical half-cell (Fig. 1 and 2) comprises an electrode chamber 10 is supplied into the 'on a filler neck 12 or the like. Electrolyte. The electrolyte also reaches a liquid space 14 via corresponding connections. The half cell is separated from another half cell via an ion exchange membrane 16. Furthermore, a plurality of gas pockets 18, 20, 22, 24 arranged one above the other are provided. The gas pockets 18, 20, 22, 24 are separated from the electrode space 10 by a gas diffusion electrode 36, which serves as a cathode in DE 196 22 744. The individual gas pockets 18, 20, 22, 24 are via connecting channels
  • the gas present in the gas pockets 18, 20, 22, 24 flows through outlet openings 28 into the connecting channels 26 and out of these through inlet openings 30 into the gas pocket lying above.
  • the direction of flow of the oxygen, for example, in the gas pockets is shown in FIG. 1 by the dashed arrows 32.
  • the lowermost gas pocket 18 is connected to a gas supply device, for example, via a feed connector 34.
  • the gas also exits from the upper gas pocket 24 through outlet openings 28 into the rear space 14 of the half cell and is discharged from there together with the electrolyte via a nozzle 11.
  • Another disadvantage is that larger amounts of electrolyte get into the gas pocket and have to be removed accordingly. It was found that this. Electrolyte cannot always be completely removed from the gas pocket and therefore accumulates in this gas pocket.
  • the electrolyte enrichment in the Gas pocket is favored by the fact that the gas / liquid outlet of the gas pocket is located opposite the gas inlet point. The increased fluid supply is noticeable, for example, by an increase in the electrolysis voltage.
  • the object of the invention is to provide an electrochemical half cell with gas pockets in which the risk of electrolyte entering the gas pockets is reduced.
  • a retaining element is arranged within the connecting channel through which at least two gas pockets are connected to one another.
  • the retention element serves to retain electrolyte located in the connection channel.
  • the retaining element can be a retaining element designed like a labyrinth.
  • droplets entrained by the gas flow are retained by the retaining element, since they cannot pass through the particularly labyrinthine structure of the retaining element.
  • At least the retention element ensures that a large part of the electrolyte does not pass through the retention element.
  • a mesh, fabric, braid, fleece or foam is preferably used as the retaining element.
  • this is an irregular one
  • Fabrics such as a felt-like material, preferably made of metal, plastic or ceramic. In a cost-effective embodiment, this can be a ball of metal wire.
  • Another essential element of the invention is the preferred arrangement of the
  • Retaining element in the connecting channel An arrangement is preferred here of the retaining element in the area of the inlet opening. This has the advantage that no or at most extremely small amounts of electrolyte can pass through the retaining element.
  • the retaining element is preferably arranged in the part of the connecting channel which is filled with gas, the retaining element being arranged closer to the inlet opening than to the electrolyte surface.
  • the arrangement of the retaining element in the upper third is particularly preferred.
  • the connecting channel or the gas bell particularly advantageously extends over two gas pocket heights. At the lower edge of the lower gas pocket, the gas comes out of the gas pocket and is collected directly through the connecting channel acting as a gas collection device and to the gas inlet opening of the one above it
  • the gas inlet opening is preferably located at the upper edge of the gas pocket.
  • a corresponding liquid level is established in the connecting channel.
  • the retaining element is arranged above this liquid level.
  • FIG. 1 shows a schematic cross section through the half cell according to the invention parallel to the gas diffusion electrode according to the prior art.
  • Fig. 2 shows a section of a schematic sectional view along the
  • FIG. 1 shows a schematic sectional view of a preferred embodiment of the invention, corresponding in principle to the sectional view shown in FIG. 2.
  • the structure of the electrochemical half-cell according to the invention corresponds fundamentally to that shown in FIGS. 1 and 2 described structure.
  • the same or similar components are therefore designated with the same reference numerals in FIG. 3.
  • a retaining element 40 is arranged in the connecting channel 26, which connects the two gas pockets 20, 22 as shown in FIG. 3 as an example.
  • the retaining element 40 is, for example, glued into the connecting channel 26 or held in it due to friction. Gas emerges from the lower gas pocket 20 in FIG. 3 through the outlet opening 28 arranged in the lower region of the gas pocket 20. The gas is collected by the connecting channel 26, which is open at the bottom, and rises in this.
  • Connection channel 26 is located depending on the pressure of electrolyte 42.
  • the height of an electrolyte surface 44 depends on the pressure conditions.
  • the gas emerging from the outlet opening 28 flows upward in the direction of the arrow 46 and, at the electrolyte surface 44, enters an area 48 of the connecting channel 26 filled with gas.
  • Electrolyte 42 is entrained by the gas bubbles 50 into the area 48 filled with gas.
  • the entrained electrolyte is then retained or separated by the retaining element 40, so that no or only small amounts of electrolyte reach the area 52 above the retaining element 40.
  • the gas After passing through the retaining element 40, the gas then passes into the gas pocket 22 lying above it through the in the upper region of the
  • Corresponding connecting channels 26 described with reference to FIG. 3 with retaining elements 40 provided and arranged according to the invention are also arranged in the connecting channels 26 connecting the other gas pockets 18, 20, 22, 24 (FIG. 1).

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)
  • Water Treatment By Electricity Or Magnetism (AREA)
  • Hybrid Cells (AREA)

Abstract

An electrochemical half cell, particularly suitable for the production of chlorine from an aqueous solution of an alkaline chloride, comprises an electrode chamber (10) for electrolyte. Several gas pockets (20, 22) for gas are also provided. A gas diffusion electrode (36) separates the gas pockets (20, 22) from the electrode chamber (10). A connecting channel (26) is also provided, by means of which the two gas pockets (20, 22) are connected to each other. Gas in the lower gas pocket (20) can flow into the connecting channel (26) through an outlet opening (28). Said gas climbs therein in the direction of the arrow (46) and arrives in a second gas pocket (22), lying thereabove, through an inlet opening (30). According to the invention, a non-return element (40) is arranged in the connecting channel (26) to avoid ingress of electrolyte (42) into the gas pocket (22).

Description

Elektrochemische Halbzelle Electrochemical half cell
Die Erfindung betrifft eine elektrochemische Halbzelle, die insbesondere zur elektrochemischen Herstellung von Chlor aus wässrigen Lösungen eines Alkalichlorids mittels Gasdiffüsionselektrode geeignet ist.The invention relates to an electrochemical half cell which is particularly suitable for the electrochemical production of chlorine from aqueous solutions of an alkali metal chloride by means of a gas diffusion electrode.
Aus DE 196 22 744 ist eine Elektrolysezelle zur Herstellung von Chlor und Natronlauge durch Elektrolyse mittels Gasdiffusionselektroden bei Einsatz einer Druckkompensation zwischen dem höhenabhängigen Druck der Natronlauge vor derDE 196 22 744 describes an electrolysis cell for the production of chlorine and sodium hydroxide solution by electrolysis using gas diffusion electrodes when using pressure compensation between the height-dependent pressure of the sodium hydroxide solution before
Gasdiffusionselektrode und dem konstanten Druck des Sauerstoffs hinter der Gasdiffüsionselektrode und der Führung des Sauerstoffs durch Gastaschen bekannt.Gas diffusion electrode and the constant pressure of the oxygen behind the gas diffusion electrode and the passage of oxygen through gas pockets known.
Im Falle der Alkalihalogenid-Elektrolyse wird die Gasdiffüsionselektrode als Sauerstoffverzehrkathode betrieben. Bei der Gasdiffüsionselektrode handelt es sich in diesem Fall um eine offenporige Membran. Diese ist zwischen Elektrolyt undIn the case of alkali halide electrolysis, the gas diffusion electrode is operated as an oxygen consumption cathode. In this case, the gas diffusion electrode is an open-pore membrane. This is between electrolyte and
Gasraum angeordnet und ermöglicht an der Dreiphasengrenze zwischen Elektrolyt,Gas space arranged and enables on the three-phase boundary between electrolyte,
Katalysator und Sauerstoff eine Sauerstoffreduktion. Die . Gasdiffüsionselektrode kann z.B. nach dem in der DE-A-37 10 168 beschriebenen Verfahren hergestellt werden. Die Dichtigkeit der Gasdiffüsionselektrode ist jedoch nur bis zu einem endlichen Druckgefälle zwischen Gasseite und Flüssigkeitsseite vorhanden. Ist derCatalyst and oxygen an oxygen reduction. The . Gas diffusion electrode can e.g. be prepared by the method described in DE-A-37 10 168. However, the tightness of the gas diffusion electrode is only present up to a finite pressure drop between the gas side and the liquid side. Is the
Gasdruck zu hoch, bricht Gas durch die Elektrode und die Funktion der Elektrode ist gestört. Ist hingegen der Flüssigkeitsdruck zu hoch, wird zunächst dieGas pressure too high, gas breaks through the electrode and the function of the electrode is disturbed. If, on the other hand, the liquid pressure is too high the
Dreiphasengrenze in Richtung Gasseite verlagert oder aber es kommt zu einem Flüssigkeitsdurchbruch von Elektrolyt in den Gasraum.Three-phase boundary shifted towards the gas side or there is a liquid breakthrough of electrolyte into the gas space.
Zur Druckkompensation des höhenäbhängigen Drucks in dem Elektrolyt ist in DE 196 22 744 das Unterteilen des Gasraums in mehrere Gastaschen vorgeschlagen. Die elektrochemische Halbzelle (Fig. 1 und 2) weist einen Elektrodenraum 10 auf, in den ' über einen Einfüllstutzen 12 oder dgl. Elektrolyt zugeführt wird. Über entsprechende Verbindungen gelangt der Elektrolyt auch in einen Flüssigkeitsraum 14. Die darge- stellte Halbzelle ist über eine Ionenaustauschermembran 16 von einer weiteren Halbzelle getrennt. Des Weiteren sind mehrere übereinander angeordnete Gastaschen 18,20,22,24 vorgesehen. Die Gastaschen 18,20,22,24 werden von dem Elektrodenraum 10 durch eine Gasdiffüsionselektrode 36 getrennt, die in DE 196 22 744 als Kathode dient. Die einzelnen Gastaschen 18,20,22,24 sind über NerbindungskanäleTo compensate for the height-dependent pressure in the electrolyte, DE 196 22 744 proposes dividing the gas space into several gas pockets. The electrochemical half-cell (Fig. 1 and 2) comprises an electrode chamber 10 is supplied into the 'on a filler neck 12 or the like. Electrolyte. The electrolyte also reaches a liquid space 14 via corresponding connections. The half cell is separated from another half cell via an ion exchange membrane 16. Furthermore, a plurality of gas pockets 18, 20, 22, 24 arranged one above the other are provided. The gas pockets 18, 20, 22, 24 are separated from the electrode space 10 by a gas diffusion electrode 36, which serves as a cathode in DE 196 22 744. The individual gas pockets 18, 20, 22, 24 are via connecting channels
26, bei denen es sich beispielsweise um Gasglocken handelt, miteinander verbunden. Das in den Gastaschen 18,20,22,24 vorhandene Gas strömt in Abhängigkeit des Drucks innerhalb der einzelnen Gastaschen durch Auslassöffnungen 28 in die Nerbindungskanäle 26 und aus diesen durch Einlassöffhungen 30 in die darüber liegende Gastasche. Die Flussrichtung des beispielsweise in den Gastaschen befindlichen Sauerstoffs ist in Fig. 1 durch die gestrichelten Pfeile 32 dargestellt. Die unterste Gastasche 18 ist beispielsweise über einen Zuführstutzen 34 mit einer Gaszuführeinrichtung verbunden. Aus der oberen Gastasche 24 tritt das Gas ebenfalls über Auslassöffnungen 28 in den Rückraum 14 der Halbzelle und wird von dort zusammen mit dem Elektrolyten über einen Stutzen 11 abgeführt. Durch das26, which are, for example, gas bells, connected to one another. Depending on the pressure within the individual gas pockets, the gas present in the gas pockets 18, 20, 22, 24 flows through outlet openings 28 into the connecting channels 26 and out of these through inlet openings 30 into the gas pocket lying above. The direction of flow of the oxygen, for example, in the gas pockets is shown in FIG. 1 by the dashed arrows 32. The lowermost gas pocket 18 is connected to a gas supply device, for example, via a feed connector 34. The gas also exits from the upper gas pocket 24 through outlet openings 28 into the rear space 14 of the half cell and is discharged from there together with the electrolyte via a nozzle 11. By the
Vorsehen mehrerer, mindestens zweier übereinander angeordneter Gastaschen findet eine Druckkompensation statt, so dass höhere Elektrolysezellen realisierbar sind. Über die Gasauslässe 28 der Gastaschen 18,20,22,24 gelangt auch sich in den Gastaschen bildendes Kondensat in den Flüssigkeitsraum 14.Providing several, at least two gas pockets arranged one above the other, pressure compensation takes place, so that higher electrolysis cells can be realized. Condensate forming in the gas pockets also enters the liquid space 14 via the gas outlets 28 of the gas pockets 18, 20, 22, 24.
Da das gesamte Gas, das über die Gaszuführung 34 in die unterste Gastasche 18 eingebracht wird, in dem Verbindungskanal 26 bzw. durch die Gasglocke gesammelt wird, entsteht innerhalb der Gasglocke eine hohe Strömungsgeschwindigkeit. Somit können Elektrolyttropfen mit in die darüber liegende, nächste Gastasche 20 gerissen werden, wodurch die Funktion der Gasdiffüsionselektrode verschlechtert wird, da dieSince all of the gas which is introduced into the lowermost gas pocket 18 via the gas supply 34 is collected in the connecting channel 26 or through the gas bell, a high flow velocity occurs within the gas bell. Electrolyte drops can thus be torn into the overlying next gas pocket 20, whereby the function of the gas diffusion electrode is impaired since the
Gasdiffüsionselektrode im Gaseintrittsbereich der Gastasche mit Elektrolyttröpfchen kontaktiert, d.h. aktive Elektrodenoberfläche teilweise verloren geht. Ebenso nachteilig wirkt sich aus, dass größere Mengen Elektrolyt in die Gastasche gelangen und dementsprechend wieder entfernt werden müssen. Es wurde festgestellt, dass dieser. Elektrolyt nicht immer vollständig aus der Gastasche entfernt werden kann und sich daher in dieser Gastasche anreichert. Die Elektrolytanreicherung in der Gastasche wird dadurch begünstigt, dass sich der Gas-/Flüssigkeitsauslass der Gastasche gegenüber der Gaseinlassstelle befindet. Bemerkbar wird die vermehrte Flüssigkeitszuführ z.B. durch eine Erhöhung der Elektrolysespannung.Gas diffusion electrode in the gas inlet area of the gas pocket contacted with electrolyte droplets, ie active electrode surface is partially lost. Another disadvantage is that larger amounts of electrolyte get into the gas pocket and have to be removed accordingly. It was found that this. Electrolyte cannot always be completely removed from the gas pocket and therefore accumulates in this gas pocket. The electrolyte enrichment in the Gas pocket is favored by the fact that the gas / liquid outlet of the gas pocket is located opposite the gas inlet point. The increased fluid supply is noticeable, for example, by an increase in the electrolysis voltage.
Aufgabe der Erfindung ist es, eine elektrochemische Halbzelle mit Gastaschen zu schaffen, bei der die Gefahr des Eintretens von Elektrolyt in die Gastaschen verringert ist.The object of the invention is to provide an electrochemical half cell with gas pockets in which the risk of electrolyte entering the gas pockets is reduced.
Die Lösung der Aufgabe erfolgt erfindungsgemäß durch die Merkmale des An- spruchs 1.According to the invention, the object is achieved by the features of claim 1.
Erfindungsgemäß ist innerhalb des Verbindungskanals, durch den mindestens zwei Gastaschen miteinander verbunden werden, ein Rückhalteelement angeordnet. Das Rückhalteelement dient dazu, in dem Verbindungskanal befindlichen Elektrolyt zurückzuhalten. Beispielsweise kann es sich bei dem Rückhalteelement um ein labyrinthartig ausgestaltetes Rückhalteelement handeln. Dies führt dazu, dass von dem Gasstrom mitgerissene Tröpfchen von dem Rückhalteelement zurückgehalten werden, da sie nicht durch die insbesondere labyrinthartige Struktur des Rückhalteelements hindurchgelangen können. Zumindest ist durch das Rückhalteelement sichergestellt, dass ein Großteil des Elektrolyts das Rückhalteelement nicht passiert.According to the invention, a retaining element is arranged within the connecting channel through which at least two gas pockets are connected to one another. The retention element serves to retain electrolyte located in the connection channel. For example, the retaining element can be a retaining element designed like a labyrinth. As a result, droplets entrained by the gas flow are retained by the retaining element, since they cannot pass through the particularly labyrinthine structure of the retaining element. At least the retention element ensures that a large part of the electrolyte does not pass through the retention element.
Hierdurch ist ein Beeinträchtigen der Funktion der Elektrode durch in die Gastaschen gelangenden Elektrolyt vermieden.This prevents the electrode from being impaired by the electrolyte entering the gas pockets.
Als Rückhalteelement wird bevorzugt ein Netz, Gewebe, Geflecht, Vlies oder Schaum eingesetzt. Insbesondere handelt es sich hierbei um ein unregelmäßigesA mesh, fabric, braid, fleece or foam is preferably used as the retaining element. In particular, this is an irregular one
Gewebe, wie ein filzartiges Material aus vorzugsweise Metall, Kunststoff oder Keramik. In einer kostengünstigen Ausgestaltung kann es sich hierbei um ein Knäuel aus Metalldraht handeln.Fabrics, such as a felt-like material, preferably made of metal, plastic or ceramic. In a cost-effective embodiment, this can be a ball of metal wire.
Ein weiteres wesentliches Element der Erfindung ist die bevorzugte Anordnung desAnother essential element of the invention is the preferred arrangement of the
Rückhalteelements in dem Verbindungskanal. Bevorzugt ist hierbei eine Anordnung des Rückhalteelements im Bereich der- Einlassöffnung. Dies hat den Vorteil, dass keine oder allenfalls äußerst geringe Mengen an Elektrolyt das Rückhalteelement passieren können. Vorzugsweise ist das Rückhalteelement in dem Teil des Verbindungskanals angeordnet, der mit Gas gefüllt ist, wobei das Rückhalteelement näher an der Einlassöffnung als an der Elektrolytoberfläche angeordnet ist.Retaining element in the connecting channel. An arrangement is preferred here of the retaining element in the area of the inlet opening. This has the advantage that no or at most extremely small amounts of electrolyte can pass through the retaining element. The retaining element is preferably arranged in the part of the connecting channel which is filled with gas, the retaining element being arranged closer to the inlet opening than to the electrolyte surface.
Besonders bevorzugt ist die Anordnung des Rückhalteelements in diesem Bereich des Verbindungskanals in der mit der Einlassöffnung verbundenen Hälfte, d.h. bei vertikal angeordneten Verbindungskanälen in der oberen Hälfte des mit Gas gefüllten Teils der Verbindungskanäle. Besonders bevorzugt ist die Anordnung des Rückhalte- elements im oberen Drittel.The arrangement of the retaining element in this area of the connecting channel in the half connected to the inlet opening, i.e. with vertically arranged connecting channels in the upper half of the gas-filled part of the connecting channels. The arrangement of the retaining element in the upper third is particularly preferred.
Besonders vorteilhaft reicht der Verbindungskanal bzw. die Gasglocke über zwei Gastaschenhöhen. Am unteren Rand der unteren Gastasche gelangt das Gas aus der Gastasche heraus und wird direkt durch den als Gassammeivorrichtung wirkenden Verbindungskanal gesammelt und zur Gaseinlassöffnung der darüber liegendenThe connecting channel or the gas bell particularly advantageously extends over two gas pocket heights. At the lower edge of the lower gas pocket, the gas comes out of the gas pocket and is collected directly through the connecting channel acting as a gas collection device and to the gas inlet opening of the one above it
Gastasche geleitet. Die Gaseinlassöffiiung befindet sich vorzugsweise am oberen Rand der Gastasche. Je nach Druckverhältnissen stellt sich ein entsprechender Flüssigkeitsstand in dem Verbindungskanal ein. Oberhalb dieses Flüssigkeitsstandes ist das Rückhalteelement angeordnet.Gas pocket headed. The gas inlet opening is preferably located at the upper edge of the gas pocket. Depending on the pressure conditions, a corresponding liquid level is established in the connecting channel. The retaining element is arranged above this liquid level.
Nachfolgend wird die Erfindung unter Bezugnahme auf die anliegenden Zeichnungen näher erläutert. Es zeigen:The invention is explained in more detail below with reference to the accompanying drawings. Show it:
Fig. 1 einen schematischen Querschnitt durch die erfindungsgemäße Halb- zelle parallel zur Gasdiffüsionselektrode nach dem Stand der Technik.1 shows a schematic cross section through the half cell according to the invention parallel to the gas diffusion electrode according to the prior art.
Fig. 2 einen Ausschnitt aus einer schematischen Schnittansicht entlang derFig. 2 shows a section of a schematic sectional view along the
Linie A-A' in Fig. 1 und Fig. 3 eine, prinzipiell der in Fig. 2 dargestellten Schnittansicht entsprechende, schematische Schnittansicht einer bevorzugten Aus- fiihrungsform der Erfindung.Line AA 'in Fig. 1 and 3 shows a schematic sectional view of a preferred embodiment of the invention, corresponding in principle to the sectional view shown in FIG. 2.
Der Aufbau der elektrochemischen Halbzelle gemäß der Erfindung entspricht grundlegend dem anhand der Fign. 1 und 2 beschriebenen Aufbau. Gleiche oder ähnliche Bestandteile sind daher in Fig. 3 mit den selben Bezugszeichen bezeichnet.The structure of the electrochemical half-cell according to the invention corresponds fundamentally to that shown in FIGS. 1 and 2 described structure. The same or similar components are therefore designated with the same reference numerals in FIG. 3.
Erfindungsgemäß ist in dem Verbindungskanal 26, der wie in Fig. 3 als Beispiel dargestellt, die beiden Gastaschen 20,22 verbindet, ein Rückhalteelement 40 angeordnet. Das Rückhalteelement 40 ist beispielsweise in den Verbindungskanal 26 eingeklebt oder auf Grund von Reibung in diesem gehalten. Aus der in Fig. 3 unteren Gastasche 20 tritt Gas durch die im unteren Bereich der Gastasche 20 angeordnete Auslassöffnung 28 aus. Das Gas wird durch den Verbindungskanal 26, der nach unten offen ist, aufgefangen und steigt in diesem nach oben. Innerhalb desAccording to the invention, a retaining element 40 is arranged in the connecting channel 26, which connects the two gas pockets 20, 22 as shown in FIG. 3 as an example. The retaining element 40 is, for example, glued into the connecting channel 26 or held in it due to friction. Gas emerges from the lower gas pocket 20 in FIG. 3 through the outlet opening 28 arranged in the lower region of the gas pocket 20. The gas is collected by the connecting channel 26, which is open at the bottom, and rises in this. Within the
Verbindungskanals 26 befindet sich in Abhängigkeit des Drucks Elektrolyt 42. Die Höhenlage einer Elektrolytoberfläche 44 hängt von den Druckverhältnissen ab. Das aus der Austrittsöffhung 28 austretende Gas strömt in Richtung des Pfeils 46 nach oben und tritt an der Elektrolytoberfläche 44 in einen mit Gas gefüllten Bereich 48 des Verbindungskanals 26. Hierbei wird von den Gasbläschen 50 Elektrolyt 42 in den mit Gas gefüllten Bereich 48 mitgerissen. Der mitgerissene Elektrolyt wird sodann von dem Rückhalteelement 40 zurückgehalten bzw. abgeschieden, so dass in dem Bereich 52 oberhalb des Rückhalteelements 40 kein oder nur geringe Mengen an Elektrolyt gelangen. Nach dem Passieren des Rückhalteelements 40 gelangt das Gas sodann in die darüber liegende Gastasche 22 durch die im oberen Bereich derConnection channel 26 is located depending on the pressure of electrolyte 42. The height of an electrolyte surface 44 depends on the pressure conditions. The gas emerging from the outlet opening 28 flows upward in the direction of the arrow 46 and, at the electrolyte surface 44, enters an area 48 of the connecting channel 26 filled with gas. Electrolyte 42 is entrained by the gas bubbles 50 into the area 48 filled with gas. The entrained electrolyte is then retained or separated by the retaining element 40, so that no or only small amounts of electrolyte reach the area 52 above the retaining element 40. After passing through the retaining element 40, the gas then passes into the gas pocket 22 lying above it through the in the upper region of the
Gastasche angeordnete Einlassöffhung 30.Gas pocket arranged inlet opening 30.
Entsprechende anhand Fig. 3 beschriebene Verbindungskanäle 26 mit erfindungsgemäß vorgesehenen und angeordneten Rückhalteelementen 40 sind auch in den die übrigen Gastaschen 18,20,22,24 (Fig. 1) verbindenden Verbindungskanälen 26 angeordnet. Corresponding connecting channels 26 described with reference to FIG. 3 with retaining elements 40 provided and arranged according to the invention are also arranged in the connecting channels 26 connecting the other gas pockets 18, 20, 22, 24 (FIG. 1).

Claims

Patentansprüche claims
1. Elektrochemische Halbzelle, insbesondere zur elektrochemischen Herstellung von Chlor aus wässrigen Lösungen eines Alkalichlorids, umfassend wenigstens1. Electrochemical half cell, in particular for the electrochemical production of chlorine from aqueous solutions of an alkali metal chloride, comprising at least
einen Elektrodenraum (10) zur Aufnahme von Elektrolyt, wobei der Elektrodenraum eine Elektrolytzuführung (12) und Elektrolytabführung (11) aufweist,an electrode space (10) for receiving electrolyte, the electrode space having an electrolyte feed (12) and electrolyte discharge (11),
mehrere Gastaschen (18,20,22,24) zur Aufnahme von Gas, wobei die unterste Gastasche (18) eine Gaszuführung (34) aufweist,a plurality of gas pockets (18, 20, 22, 24) for receiving gas, the bottom gas pocket (18) having a gas supply (34),
einen zwei Gastaschen (20,22) miteinander verbindenden Verbindungskanal (26), wobei das Gas durch eine Auslassöff ung (28) einer ersten Gastaschea connecting channel (26) connecting two gas pockets (20, 22) to one another, the gas passing through an outlet opening (28) of a first gas pocket
(20) in den Verbindungskanal (26) und von diesem durch eine Einlassöffnung (30) in eine zweite Gastasche (22) strömt,(20) flows into the connecting channel (26) and flows from it through an inlet opening (30) into a second gas pocket (22),
eine den Elektrodenraum (10) von den Gastaschen (18,20,22,24) trennende Gasdiffüsionselektrode (36) unda gas diffusion electrode (36) separating the electrode space (10) from the gas pockets (18, 20, 22, 24) and
gekennzeichnet durchmarked by
ein in dem Verbindungskanal (26) angeordnetes Rückhalteelement (40) zum Zurückhalten von in dem Verbindungskanal (26) befindlichen Elektrolyten.a retaining element (40) arranged in the connecting channel (26) for retaining electrolytes located in the connecting channel (26).
2. Elektrochemische Halbzelle nach Anspruch 1, dadurch gekennzeichnet, dass das Rückhalteelement (40) auf einem Netz, Gewebe, Geflecht, Vlies oder Schaum aus Kunststoff, Metall oder Keramik basiert. 2. Electrochemical half-cell according to claim 1, characterized in that the retaining element (40) is based on a mesh, fabric, braid, fleece or foam made of plastic, metal or ceramic.
3. Elektrochemische Halbzelle nach einem der Ansprüche 1 bis 2, dadurch gekennzeichnet, dass das Rückhalteelement (40) im Bereich der Einlassöffnung (30) angeordnet ist.3. Electrochemical half cell according to one of claims 1 to 2, characterized in that the retaining element (40) is arranged in the region of the inlet opening (30).
4. Elektrochemische Halbzelle nach einem der Ansprüche 1 bis 3, dadurch gekennzeichnet, dass der Verbindungskanal (26) teilweise mit Elektrolyt und teilweise mit Gas gefüllt ist und das Rückhalteelement (40) näher an der Einlassöffiiung (30) als an der Elektrolytoberfläche (44) angeordnet ist.4. Electrochemical half-cell according to one of claims 1 to 3, characterized in that the connecting channel (26) is partly filled with electrolyte and partly with gas and the retaining element (40) closer to the inlet opening (30) than to the electrolyte surface (44) is arranged.
5. Elektrochemische Halbzelle nach Anspruch 4, dadurch gekennzeichnet, dass das Rückhalteelement in der mit der Einlassöffiiung (30) verbundenen Hälfte des mit Gas gefüllten Teils (48) des Verbindungskanals (26) angeordnet ist.5. Electrochemical half cell according to claim 4, characterized in that the retaining element is arranged in the half of the gas-filled part (48) of the connecting channel (26) connected to the inlet opening (30).
6. Elektrochemische Halbzelle nach einem der Ansprüche 1 bis 5, dadurch ge- kennzeichnet, dass die Auslassöffnung (28) im unteren Bereich einer Gastasche (20) und die Einlassöffnung (30) im oberen Bereich einer Gastasche (22) angeordnet ist. 6. Electrochemical half cell according to one of claims 1 to 5, characterized in that the outlet opening (28) is arranged in the lower region of a gas pocket (20) and the inlet opening (30) in the upper region of a gas pocket (22).
EP02785267A 2001-10-25 2002-10-22 Electrochemical half cell Withdrawn EP1442158A2 (en)

Applications Claiming Priority (3)

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DE10152791 2001-10-25
DE10152791A DE10152791A1 (en) 2001-10-25 2001-10-25 Process for the production of chlorine and caustic soda by electrolysis using a gas diffusion electrode demister
PCT/EP2002/011787 WO2003035939A2 (en) 2001-10-25 2002-10-22 Electrochemical half cell

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TWI568888B (en) 2011-09-15 2017-02-01 第諾拉工業公司 Gas-diffusion electrode
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EP3028324A4 (en) 2013-07-31 2017-01-11 Aquahydrex Pty Ltd Method and electrochemical cell for managing electrochemical reactions
AU2020216203A1 (en) 2019-02-01 2021-08-05 Aquahydrex, Inc. Electrochemical system with confined electrolyte
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DE4444114C2 (en) * 1994-12-12 1997-01-23 Bayer Ag Electrochemical half cell with pressure compensation
DE19622744C1 (en) * 1996-06-07 1997-07-31 Bayer Ag Pressure-compensated electrochemical half-cell
US6093853A (en) * 1997-07-04 2000-07-25 Nok Corporation Phenylenediamine derivative, production method thereof and antioxidant for rubber using it as effective constituent
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JP2005506455A (en) 2005-03-03
CA2464638A1 (en) 2003-05-01
US20040262153A1 (en) 2004-12-30
HUP0401580A3 (en) 2005-07-28
KR20040062953A (en) 2004-07-09
DE10152791A1 (en) 2003-05-08
AU2002350591A1 (en) 2003-05-06
WO2003035939A3 (en) 2004-01-08
HUP0401580A2 (en) 2004-11-29
CN1575354A (en) 2005-02-02

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