DK171509B1

DK171509B1 - Process, and an electrolysis vessel, for electrolytic water treatment

Info

Publication number: DK171509B1
Application number: DK117793A
Authority: DK
Inventors: Claus Fabricius
Original assignee: Guldager As
Priority date: 1993-10-19
Filing date: 1993-10-19
Publication date: 1996-12-09
Also published as: DK117793A; DK117793D0

Description

DK 171509 B1 5 10 15DK 171509 B1 5 10 15

Fremgangsmåde og elektrolysebeholder til elektrolytisk vandbehandling.Process and electrolytic container for electrolytic water treatment.

20 Opfindelsen vedrører en fremgangsmåde som angivet i krav 1's indledning til behandling af vand i en elektrolysebeholder, fortrinsvis beregnet for korrosionsbeskyttelse af brugs-og procesvandssystemer, hvor der ved ilægning af en perforeret skillevæg mellem anoden og katoden og en styret strømning af vandet kan sikres, at vandet får en påvirkning af det katodiske miljø.The invention relates to a method as set forth in the preamble of claim 1 for treating water in an electrolytic vessel, preferably intended for corrosion protection of utility and process water systems, whereby by inserting a perforated partition between the anode and the cathode and a controlled flow of the water, that the water has an impact on the cathodic environment.

25 Med elektrolytisk vandbehandling er det kendt at behandle vandet i større beholdere, hvor anoderne, fortrinsvis aluminium, er placeret i den øverste tredjedel med en • konstruktion, der sikrer en god strømfordeling mellem anoden og beholderen, der fungerer som katode.With electrolytic water treatment, it is known to treat the water in larger vessels, where the anodes, preferably aluminum, are located in the upper third with a structure which ensures a good distribution of current between the anode and the cathode acting.

Med den kendte teknik kan man konstatere et meget stort spild af aluminium, som først 30 og fremmest viser sig som slam, typisk hvor den positive ion i det isoelektriske punkt -der i praksis ligger få centimeter fra anoden i gængs vand med en pH-værdi højere end 7 - ændres til en negativ. Denne ændring i ion-ladningen som beskrevet i dansk patentskrift nr. 167870, har vist sig nødvendig for at aluminium kan fungere som korrosionsinhibitor i et efterfølgende rørsystem.With the prior art, a very large waste of aluminum can be found, which first turns out to be sludge, typically where the positive ion in the isoelectric point - in practice is located a few centimeters from the anode in normal water with a pH value. higher than 7 - changes to a negative. This change in the ion charge as described in Danish Patent No. 167870 has proved necessary for aluminum to act as a corrosion inhibitor in a subsequent pipe system.

35 Med denne erkendelse er den kendte teknik uhensigtsmæssig, dels ved at kræve en vis behandlingstid for at aluminium kan få den nødvendige kontakt med katoden, dels ved det meget store spild af anodemateriale, som vil forbinde sig med vandets anioner.35 With this recognition, the prior art is inappropriate, partly by requiring some treatment time for aluminum to make the necessary contact with the cathode, and partly by the very large waste of anode material which will associate with the anions of the water.

Med anvendelse af små beholdere har man haft væsentlige problemer med belægninger på katodefladen, fordi relativ større strømtætheder giver uforholdsmæssig større 40 kalkudfældning og ved de turbulente forhold i en lille beholder vil der være et meget 2 DK 171509 B1 større spild af eksempelvis aktivt aluminationer, som nedbrydes til en energifattig inaktiv aluminiumhydroxidforbindelse ved kontakt med positive aluminium-ioner.With the use of small containers there have been significant problems with coatings on the cathode surface, because relatively larger current densities give a disproportionately larger 40 lime precipitation and in the turbulent conditions in a small container there will be a much larger waste of, for example, active aluminations, which decomposes to an energy-low inactive aluminum hydroxide compound upon contact with positive aluminum ions.

5 Opfindelsen angiver en fremgangsmåde og en elektrolysebeholder, hvor det er muligt at undgå de gener, der er med den kendte elektrolyse. Dette opnås med en fremgangsmåde som angivet i krav 1's indledning, og ejendommelig ved det i den kendetegnende del af krav 1 angivne. Elektrolysebeholderen er af den i krav 3's henholdsvis krav 4’s indledning angivne art, og ejendommelig ved det i den 10 kendetegnende del af krav 3's henholdsvis krav 4 angivne. Opfindelsen skal i det følgende nærmere forklares under henvisning til tegningen, hvor fig. 1 viser en udførelsesform for en elektrolysebeholder ifølge opfindelsen, og fig. 2 viser en yderligere udførelsesform for en elektrolysebeholder ifølge opfindelsen: På figur 1 er vist en beholder (1) i hvilken der er monteret en anode (2), en katode (3), 15 som kan være separat indlagt eller at beholderen af metal fungerer som sådan, med en tilgang af vand ved (4) og afgang af behandlet vand ved (5). Tilgang (4) fungerer samtidig som udslamning, hvor dette kan tilvejebringes ved at anbringe en trevejsventil (7). Mellem anoden og katoden er anbragt en perforeret skilleplade af elektrisk ikke-ledende materiale (6). I beholderen tilvejebringes en styret strømning, således at vandet 20 først passerer anoden, der er af aluminium og/ eller zink, hvor vandet beriges med en positiv metal-ion og derefter gennem skillepladen umiddelbart kommer i kontakt med katoden, som kan være en rustfri stålplade og derved bliver ændret til en negativ ion.The invention provides a method and an electrolysis container where it is possible to avoid the genes associated with the known electrolysis. This is achieved by a method as set forth in the preamble of claim 1 and peculiar to that of the characterizing part of claim 1. The electrolytic receptacle is of the kind specified in the preamble of claim 3 and claim 4, respectively, and peculiar to the characterizing part of claim 3 and claim 4, respectively. The invention will now be explained in more detail with reference to the drawing, in which 1 shows an embodiment of an electrolysis container according to the invention, and fig. 2 shows a further embodiment of an electrolysis container according to the invention: Fig. 1 shows a container (1) in which is mounted an anode (2), a cathode (3), which can be separately inserted or that the metal container works as such, with an inflow of water at (4) and exit of treated water at (5). Inlet (4) simultaneously acts as slurry where this can be provided by applying a three-way valve (7). Between the anode and cathode is a perforated separating plate of electrically non-conductive material (6). In the vessel, a controlled flow is provided so that the water 20 first passes through the anode which is of aluminum and / or zinc, where the water is enriched with a positive metal ion and then immediately contacts the cathode, which may be a stainless steel plate. thereby changing to a negative ion.

Der tilstræbes her den kortest muligt praktiske afstand, således at den positive aluminium-ion spontant passerer det isoelektriske punkt ved at komme direkte i det 25 katodiske miljø, hvor katodens hydroxyl-ioner vil sikre dannelsen af aluminat- og/eller zinkat-ionen. Vandet kommer ikke mere i kontakt med anodezonen, hvor den negative ion ellers uønsket vil ændres til en positiv. Der sker ingen slamdannelse på grund af den korte vandring i tid og rum, som ellers er et væsentligt problem med den kendte elektrolyse.The shortest practical distance is sought here so that the positive aluminum ion spontaneously passes the isoelectric point by entering directly into the cathodic environment where the hydroxyl ions of the cathode will ensure the formation of the aluminate and / or zinc cation ion. The water no longer contacts the anode zone where the negative ion will otherwise undesirably change to a positive one. No sludge formation occurs due to the short migration of time and space, which is otherwise a significant problem with the known electrolysis.

3030

Ved valg af skillepladen har det vist sig hensigtsmæssig at lade den udføre i et fleksibelt materiale, således, at der ved udslamning fra beholderen sker en vibration af pladen, som kan forplante sig til både anoden og katoden og dermed foretage en mekanisk rensning af disse for aflejringer. Det kan være hensigtsmæssigt at forsyne pladen med 35 piglignende udvækster, som forbedrer rensning. Det er ønskeligt, at det samlede areal af 3 DK 171509 B1 hullerne i skillepladen er beregnet således, at der ved udslamning sker et trykfald i det indre rum (10), hvorved pladen presses mod anoden, efterfølgende at det overtryk, som opstår ved genetablering af trykket bevæger den membranlignende skillevæg mod katoden. Det kan i den forbindelse være hensigtsmæssigt at anbringe en kontraventil 5 (11) for at forstærke under- og overtrykket.In selecting the separating plate, it has been found appropriate to allow it to be made in a flexible material, so that when slurry from the container, a vibration of the plate can occur which can propagate to both the anode and the cathode and thus perform a mechanical cleaning thereof. deposits. It may be convenient to provide the plate with 35 spike-like outgrowths that enhance purification. It is desirable that the total area of the holes in the separator plate is calculated so that, when slurry, a pressure drop occurs in the inner space (10), thereby pressing the plate against the anode, followed by the overpressure resulting from re-establishment. of the pressure, the membrane-like partition moves toward the cathode. In this connection, it may be appropriate to provide a check valve 5 (11) to enhance the underpressure and overpressure.

På fig. 2 er der i beholderen (1) monteret en aluminium-og/eller zinkkatode (3), en anode, der eksempelvis kan være inert tråd, som vist ved (2) med en tilgang af vand ved (4) og en afgang (5). Også her er anbragt en skilleplade (6), som sikrer, at vandet i 10 væsentlig grad kun påvirkes af det katodiske miljø, således at den dannede aluminat - og eller zinkat-ion ikke kommer i fysisk kontakt med anodemiljøet.In FIG. 2, there is mounted in the container (1) an aluminum and / or zinc cathode (3), an anode which may be, for example, inert wire, as shown by (2) with an inlet of water at (4) and an outlet (5). ). Also here, a separator plate (6) is provided which ensures that the water is substantially affected only by the cathodic environment, so that the aluminate and or zinc cation formed do not come into physical contact with the anode environment.

Også i dette eksempel er det særdeles fordelagtigt at udføre skillepladen i et fleksibelt materiale, således at der ved trykfald ved en udslamning sker en sammenpresning 15 omkring katoden med deraf rensende effekt.In this example, too, it is particularly advantageous to design the separating plate in a flexible material, so that in case of pressure drop in a slurry, a compression 15 occurs around the cathode with its purifying effect.

Det har yderligere vist sig gunstigt særligt ved den anviste udførelsesform på figur 2, med en kort afstand mellem skilleplade og katoden at vandet tilføres ozon ved (7), hvor skillevæggens placering sikrer, at ozon kun kommer i forbindelse med katoden og derved reduceres til OH-radikaler, som ikke blot i almindelig bakteriebekæmpelse er ekstremt 20 effektivt, men yderligere har det vist sig, at aluminat- og zinkat-ionen i kraft af oxydationspotentialet udfældes meget hurtigere på metalflader i et efterfølgende rørsystem.It has further proved particularly advantageous in the embodiment shown in Figure 2, with a short distance between the partition plate and the cathode, that the water is fed to ozone at (7), where the location of the partition ensures that ozone only contacts the cathode and is thereby reduced to OH. radicals which, not only in ordinary bacterial control, are extremely effective, but further, it has been found that, by virtue of the oxidation potential, the aluminate and zinc cation are precipitated much more rapidly on metal surfaces in a subsequent pipe system.

Tilsvarende kan ozon også tilsættes i det først viste eksempel, hvor dosering kan ske ved (12) figur 1.Similarly, ozone can also be added in the first example shown, where dosing can be done in (12) Figure 1.

25 30 3525 30 35

Claims

A method of electrolytic water treatment in an electrolytic vessel having an electrode of aluminum, zinc or alloys thereof, and of the kind in which the water in full or partial flow flows through the vessel of a utility or process water system to form aluminate and / or zinc cat. ions for a subsequent corrosion protection of the pipe system 10, characterized in that an electrically insulating perforated separating plate between the anode and the cathode is placed in the electrolyte, which plate is arranged to ensure that the water is only substantially affected by the cathodic environment and that the flow in the container is controlled. in such a way that the exit from the cathodic environment is that the anode is of aluminum and / or zinc when the water supply is in the anode zone and that the cathode is of aluminum and / or zinc when the water supply is in the cathode zone.

Process according to claim 1, characterized in that ozone is added to the cathodic volume.

An electrolytic container (1) for use in a method according to claims 1 and 2 and with built-in anode (2) of aluminum and / or zinc and a cathode (3), which may be separately inserted or the container functions as known suitably. in that there is an electrically insulating perforated separating plate (6) between anode and cathode and that the inlet (4) of water is in the anode zone and the outlet (5) in the cathode zone.

Electrolysis container (1) for using the method according to claims 1 and 2 characterized in that there is an electrically insulating perforated separator plate (6) between the cathode (3) consisting of aluminum and / or zinc, and the anode (2). ) and that both (4) water and outlet (5) accesses occur in the cathodic zone.

4 DK 171509 B1 5

Electrolysis container according to claims 3 and 4, characterized in that the perforated separating plate is made of flexible material and that the total area of holes in the plate is calculated so that, when changes in the pressure, for example by a slurry with a 30 pressure drop, a movement of the plate towards the anode or cathode, which is thereby mechanically influenced, so that coatings can be cleaned and, when the pressure is restored, an opposite directed movement affecting the cathode and the anode, respectively, is effected.