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WO1998017587A1 - Procede et dispositif de traitement electrophysique de l'eau - Google Patents

Procede et dispositif de traitement electrophysique de l'eau Download PDF

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Publication number
WO1998017587A1
WO1998017587A1 PCT/AT1997/000222 AT9700222W WO9817587A1 WO 1998017587 A1 WO1998017587 A1 WO 1998017587A1 AT 9700222 W AT9700222 W AT 9700222W WO 9817587 A1 WO9817587 A1 WO 9817587A1
Authority
WO
WIPO (PCT)
Prior art keywords
water
cathode
anode
space
compartment
Prior art date
Application number
PCT/AT1997/000222
Other languages
German (de)
English (en)
Inventor
Klaus Leiter
Gerhard Walder
Klaus Neidhardt
Original Assignee
Maitron Chemiefreie Wasserbehandlung Gmbh
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 Maitron Chemiefreie Wasserbehandlung Gmbh filed Critical Maitron Chemiefreie Wasserbehandlung Gmbh
Priority to EP97943657A priority Critical patent/EP0951448A1/fr
Publication of WO1998017587A1 publication Critical patent/WO1998017587A1/fr

Links

Classifications

    • 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
    • C02F1/46—Treatment of water, waste water, or sewage by electrochemical methods
    • C02F1/4602—Treatment of water, waste water, or sewage by electrochemical methods for prevention or elimination of deposits
    • 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
    • C02F1/001—Processes for the treatment of water whereby the filtration technique is of importance
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2201/00—Apparatus for treatment of water, waste water or sewage
    • C02F2201/46—Apparatus for electrochemical processes
    • C02F2201/461—Electrolysis apparatus
    • C02F2201/46105—Details relating to the electrolytic devices
    • C02F2201/46115—Electrolytic cell with membranes or diaphragms

Definitions

  • the invention relates to a method and a device for electrolytic water treatment. More specifically, the invention relates to a method for decarbonizing industrial and drinking water, in which the water is filled into a container in which a cathode and an anode are arranged. to which an electrical voltage is applied, carbonate precipitating, whereupon decarbonized water is taken from the container as process or drinking water. Furthermore, the invention relates to a device for performing this method
  • Decarbonization in water treatment refers to the reduction of carbonate hardness.
  • the carbonate hardness corresponds to the proportion of alkaline earth ions, in particular Ca 2+ and Mg 2+ ions, which are present in the water as hydrogen carbonates and can therefore be precipitated as carbonates (for example, lime)
  • alkaline earth ions are bound to the resin in exchange for H + ions, the released H + ions react with the HC0 3 ions present in the water to form water and C0 2 , the C0 2 can be blown out of the water
  • saturation index Sl It is common to determine the saturation state of a water with a logarithmic size, the so-called saturation index Sl. to describe:
  • a method for decarbonizing metastable water is therefore to add suitable crystallization centers (lime or marble powder, certain aluminum silicates, etc.) to the water - seeding technique.
  • decarbonization is achieved by raising the pH value for drinking and industrial water by adding lime milk (Ca (OH) 2 ) and / or sodium hydroxide solution (NaOH) and / or soda (Na 2 C0 3 ) to the water.
  • lime milk Ca (OH) 2
  • NaOH sodium hydroxide solution
  • soda Na 2 C0 3
  • a further problem is the pH value of the water, which is too high after the lime precipitation (the pH value is only slightly reduced due to the carbon dioxide released in the event of lime precipitation). Consequently, further measures have to be taken, such as Add acid or C0 2 to reduce the pH value to between 7 and 8 5 after the lime precipitation
  • Electrochemistry offers alternative methods for producing the alkali (OH ' ions) required for raising the pH.
  • a method is known, for example, from EP 0 548 242, where the OH ions on a cathode are obtained directly from the water Dissolved oxygen formed In this process, however, it is important to carry out the electrode reactions below the water decomposition voltage of 1 23 volts, since otherwise H + ions are formed on the anode, which would lower the pH again. This results in the success of the process in the water existing oxygen and its electrochemical conversion at the cathode are limited
  • the necessary OH ions are now formed by electrolytic decomposition of water on the cathode.
  • a diaphragm prevents the OH ions from recombining with H + ions formed on the anode.
  • Preferred methods and devices are also used specified how the H + ions formed can be used to lower the pH of the decarbonized water. This enables a decarbonization process to be carried out which works without chemical additives and has a high decarbonization efficiency
  • Figure 1 shows a schematic representation of an electrolytic cell.
  • Figure 2 shows a schematic representation of a first exemplary embodiment of a device according to the invention for performing the method according to the invention
  • Figure 3 shows schematically the alternative structure of a diaphragm
  • Figure 4 shows schematically a further alternative structure of the diaphragm with a water withdrawal along the diaphragm
  • Figure 4a shows schematically a structure of the diaphragm with a water withdrawal across the diaphragm
  • FIG. 5 shows an exemplary embodiment suitable for continuous operation
  • FIG. 6 shows details of a further exemplary embodiment in a schematic representation
  • An electrolytic cell (see FIG. 1) is understood to mean a system in which two electrodes AK are conductively connected via an electrolyte (here water). By applying an external voltage source 1 to the electrodes, electrochemical reactions at the electrodes are made possible or a Current flow through the electrolyte causes
  • D h is generated at the cathode in addition to hydrogen OH or H + is reduced to H 2 , at the anode in addition to oxygen H + is generated or OH is oxidized to 0 2
  • a convection bar is sufficient - a diaphragm 2
  • Two spaces are created by inserting the diaphragm between the anode and cathode - a cathode space 4 and an anode space 3
  • the diaphragm must prevent the convective transport of the ions but must be such that a current flow between the anode and cathode in the electrolyte is possible when the voltage is applied. If an OH ion is generated on the cathode, for reasons of charge neutrality, either from the Anode space can be used to transport a cation as a counter ion into the cathode space through the diaphragm or an anion from the cathode space into the anode space.
  • the charge balance in the anode space can be achieved D h but also that for an effective lye - or acid production other cations than H + or other anions other than OH must be present in the electrolyte (conductive salt)
  • the molantate of the conductive salt ultimately determines the achievable alkali or acid concentration.
  • concentration of the OH - and H + ions are low in relation to the ions of the conductive salt, the ions of the conductive salt dominate the current transport via the diaphragm.
  • concentrations of OH ions and H + ions in the order of magnitude of the ion concentrations of the conductive salt, they begin to dominate the current transport through the diaphragm.
  • the concentration of OH in the cathode space or H + ions in the anode space can no longer be increased if this limit is reached, since recombination processes cancel the educational processes
  • their maximum concentrations limit the maximum alkali or acid concentration that can be produced with electrolysis.
  • Drinking water typically has ionic contents less than 10 2 mol / I, so that with the same large volumes of anode , in the anode compartment, at best, achieve a Kathodenrau and H + -Konzentrat ⁇ on corresponding to a pH-value of 2, in the cathode compartment an OH ⁇ tion concentration corresponding to a pH value of 12
  • FIG. 2 shows the diagram of an electrolytic cell for the decarbonization of water according to the invention, anode A, cathode K and diaphragm 2 having a cylindrical shape and being located in a closed container 5
  • the diaphragm 2 can be made of clay, ceramic or plastic, but also membranes, in particular ion-selective membranes, can be used.
  • membranes in particular ion-selective membranes
  • multi-layer diaphragms are suitable, for example a diaphragm consisting of a bed of fine-grain cation exchange resin between membranes
  • the raw water to be decarbonized is let in via the inlet 7 and the container 5 is filled up.
  • the valve 8 in the inlet 7 is closed and the direct voltage over 1 23 volts (for example 24 V) is applied to the electrodes A, K.
  • the water is broken down into H + and 0 2 , at the cathode K OH " and H 2 are formed.
  • the OH 'formed should be distributed as evenly as possible in the cathode space, a stirrer 6 built into the container 5 supports the homogenization Oxygen formed in the anode compartment 3 must be removed via an automatic venting valve 9.
  • the hydrogen formed in the cathode compartment 4 must also be removed via an automatic venting vent 9a
  • the pH increase causes lime to precipitate; iron or manganese ions present in larger concentrations (more than 10 mg / l) are also precipitated in the form of the corresponding carbonates.
  • the precipitated lime accumulates as lime sludge sloping floor 10 of the container
  • the lime sludge must be removed regularly by draining (by opening the drain valve 11 in line 12 and flushing out the container) - otherwise anaerobic bacteria can multiply in the lime sludge, which for example can reduce sulfates in the water to H 2 S - Even the smallest amounts of H 2 S can be smelled
  • the duration of the electrolysis and the length of time necessary for the sedimentation of the lime depend on the water composition, the electrolysis current (determines the OH production) and the water volume in the cathode compartment and can be set once for the respective water Duration of the electrolysis and the electrolysis voltage depending on suitable process-determining parameters.
  • a control device 13 can be provided, which receives the electrolysis voltage via a voltmeter 14 and the electrolysis current via an ammeter 15 as input variables.
  • a sensor 16 can be provided be, which detects the pH value, the turbidity and / or the conductivity in the cathode compartment 4 and feeds it to the control device 13 the line 17 an output signal are generated, which the voltage of the
  • Voltage source 1 changed or switched on and off
  • the water is removed from the container 5 by opening the inlet valve 8. If the inlet is close to the bottom of the container and the outlet on the cover, water is treated by stratification of the pipe water until layer% is removed to ensure that only treated, decarbonised water
  • This disadvantage can be countered by integrating a device in the arrangement which stores the H + ions generated during the electrolysis and which ensures that these are not lost again during a rinsing.
  • weakly acidic cation exchange resins or cation exchange nerves act as such a memory
  • the diaphragm 2 is an approximately 1 to 3 cm thick fill of fine-grained weakly acidic cation exchange resins 22, for example realized by filling the resins in filter socks 23 Cation exchange fibers or the nonwoven must first be converted at least partially from the so-called H-form into a Ca-form (also Mg-form is suitable), ie be loaded with calcium ions.
  • the anode compartment 3 is rinsed several times in order to prevent the formation of undesired chlorine gas concentrations.
  • the water is withdrawn directly from the anode compartment 3, the water from the cathode compartment 4 being carried out through the resin bed 22 against H + ions on the resin ask (2004)t, the thus becoming free-H + ions lower the pH value of the water
  • the pH value of the water removed can be adjusted within a wide range
  • FIG. 4 An improved construction of a diaphragm 2, which is suitable for use in chlorine-containing water and at the same time allows a pH reduction, looks as follows (FIG. 4) First of all, it is mentioned that similar to FIG. 3, where the container 5 and the lines are not shown, this container 5 is also not shown in FIG. 4. The naturally present cathode is also not shown
  • the resin bed 22 ' is delimited on the left and right by membranes 23', the resin bed is thus separated from both the anode space 3 and the cathode space 4.
  • the anode-side membrane 23 ' is preferably a cation exchange membrane in order to suppress the migration of chlorine ions into the anode space H + -Ions that are formed in the anode compartment can pass through the anode-side membrane and are bound to the resin 22 ′ via ion exchange.
  • the water is removed via a separate line 18, so that the water removed from the cathode compartment 4 runs through the resin bed.
  • the bottom 24 is perforated Anode compartment can be spooled via its own line 20
  • a water collection channel 18a is required between the resin bed and the anode-side membrane.
  • a cation exchanger can also be used with this diaphragm structure
  • the diaphragms described last are also suitable for use in low-chloride waters.
  • lime precipitation does not occur instantaneously, i.e. you have to plan a certain process time (typically 30 to 60 minutes).
  • a decarbonization system is combined as described in FIG. 2 with a downstream filter 25, which accelerates the lime precipitation from the solution (through existing lime powder or special pellets) and filters the precipitated lime from the solution.
  • a downstream filter 25 which accelerates the lime precipitation from the solution (through existing lime powder or special pellets) and filters the precipitated lime from the solution.
  • the structure, operation and maintenance of such a filter can be found, for example, in DIN 19605.
  • the process duration of 30 to 60 minutes with a treatment rate of 400 liters per hour defines a volume of decarbonization system and filter of 200 to 400 liters.
  • water is not continuously drawn from a household; if one can refer to the usual withdrawal quantities and withdrawal frequencies, much smaller systems can also be dimensioned (for a single-family house with 4 people approx. 50 liters); if necessary, the use of a filter 25 can be dispensed with.
  • a diaphragm 2 from a chess acidic cation exchange resin bed can be used again (see FIG. 4), through which filtered water is passed during removal. If the volume of the cathode chamber 4 and the average flow or withdrawal quantity are matched to one another, then there is no need for filtration.
  • the efficiency of the decarbonization can be increased, since some of the non-precipitated Ca 2+ ions are continuously returned to the cathode compartment.
  • the efficiency and the pH that can be set can be determined by means of the height of the rubble and the thickness of the resin bed and by means of the electrolysis current Taxes
  • the described invention and device is also suitable for producing seed crystals using the seeding technique.
  • Lime crystals smaller than 5 ⁇ m are particularly suitable for seeding technology, since the setting speed of these crystals is slow enough to carry these crystals from the point of origin to the entire installation system to be protected. Wherever the water is oversaturated, the growth of these crystals is particularly high in hot water generators Competitive process for quay separation on the wall
  • the invention is of course not limited to the exemplary embodiments shown.
  • multiple arrangements and / or cathodes can also be present.

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  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Hydrology & Water Resources (AREA)
  • Engineering & Computer Science (AREA)
  • Environmental & Geological Engineering (AREA)
  • Water Supply & Treatment (AREA)
  • Organic Chemistry (AREA)
  • Water Treatment By Electricity Or Magnetism (AREA)

Abstract

L'invention concerne un procédé et un dispositif de décarbonatation de l'eau sanitaire ou de l'eau potable. L'eau est introduite dans un récipient dans lequel sont placées une cathode et une anode, auxquelles est appliquée une tension électrique continue, le carbonate est alors précipité et l'eau décarbonatée est prélevée du récipient sous forme d'eau sanitaire ou d'eau potable. Ce procédé se caractérise en ce qu'il est prévu dans le récipient une membrane qui sépare la chambre contenant la cathode de la chambre contenant l'anode. L'eau à décarbonater est introduite dans la chambre contenant la cathode et en est prélevée. Entre la cathode et l'anode, une tension de plus de 1,22 volt est appliquée de manière que des molécules d'eau se décomposent par voie électrolytique au niveau de la cathode et forment des ions OH-. Il est produit dans la chambre contenant la cathode un milieu basique dans lequel est précipité du carbonate, notamment sous forme de carbonate de calcium (calcaire) et/ou de carbonate de magnésium.
PCT/AT1997/000222 1996-10-17 1997-10-17 Procede et dispositif de traitement electrophysique de l'eau WO1998017587A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP97943657A EP0951448A1 (fr) 1996-10-17 1997-10-17 Procede et dispositif de traitement electrophysique de l'eau

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
ATA1821/96 1996-10-17
AT182196 1996-10-17

Publications (1)

Publication Number Publication Date
WO1998017587A1 true WO1998017587A1 (fr) 1998-04-30

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Application Number Title Priority Date Filing Date
PCT/AT1997/000222 WO1998017587A1 (fr) 1996-10-17 1997-10-17 Procede et dispositif de traitement electrophysique de l'eau

Country Status (2)

Country Link
EP (1) EP0951448A1 (fr)
WO (1) WO1998017587A1 (fr)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19832822A1 (de) * 1998-07-21 2000-03-09 Sterff Beteiligungsgesellschaf Verfahren und Vorrichtung zur kapazitiven Demineralisierung von Ionen enthaltenden Flüssigkeiten
EP1056685A4 (fr) * 1998-02-17 2001-04-18 Potable Water Systems Ldt Cellule electrolytique avec membranes poreuses permettant de concentrer les anions
DE10002733A1 (de) * 2000-01-22 2001-07-26 Bwt Privatstiftung Hintersee Elektrolysezelle und Elektrolyseverfahren
WO2003042112A1 (fr) * 2001-11-13 2003-05-22 Radical Waters (Ip) (Pty) Limited Carbone active electrochimiquement et solutions de sel de bicarbonate
DE102012101031B4 (de) 2012-02-08 2019-02-14 Perma-Trade Wassertechnik Gmbh Verfahren zur Vermeidung von Kalkansatz

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4119518A (en) * 1975-07-16 1978-10-10 Jorge Miller Electrolytic cell for treatment of water
FR2510613A1 (fr) * 1981-07-31 1983-02-04 Orset Christian Procede electrolytique pour prevenir l'entartrage de canalisations et dispositif pour sa mise en oeuvre
CH659999A5 (en) * 1983-05-20 1987-03-13 Christ Ag Process for electrolytic decationisation and/or decarbonation of aqueous liquid streams which are in contact with alkaline earth metal carbonate precipitates
JPH0252090A (ja) * 1988-08-12 1990-02-21 Shimizu Corp 電気分解とイオン交換による健康飲用水の製造方法及びその製造装置
EP0408984A1 (fr) * 1989-07-12 1991-01-23 Joh.A. Benckiser Wassertechnik GmbH Procédé et dispositif pour le traitement physique de courants d'eau dure
WO1992006041A1 (fr) * 1990-09-28 1992-04-16 Gemeau Nouveau procede electrochimique d'adoucissement des eaux dures et appareil pour la mise en ×uvre dudit procede
EP0680932A2 (fr) * 1994-05-06 1995-11-08 United Kingdom Atomic Energy Authority Désionisation électrolytique

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4119518A (en) * 1975-07-16 1978-10-10 Jorge Miller Electrolytic cell for treatment of water
FR2510613A1 (fr) * 1981-07-31 1983-02-04 Orset Christian Procede electrolytique pour prevenir l'entartrage de canalisations et dispositif pour sa mise en oeuvre
CH659999A5 (en) * 1983-05-20 1987-03-13 Christ Ag Process for electrolytic decationisation and/or decarbonation of aqueous liquid streams which are in contact with alkaline earth metal carbonate precipitates
JPH0252090A (ja) * 1988-08-12 1990-02-21 Shimizu Corp 電気分解とイオン交換による健康飲用水の製造方法及びその製造装置
EP0408984A1 (fr) * 1989-07-12 1991-01-23 Joh.A. Benckiser Wassertechnik GmbH Procédé et dispositif pour le traitement physique de courants d'eau dure
WO1992006041A1 (fr) * 1990-09-28 1992-04-16 Gemeau Nouveau procede electrochimique d'adoucissement des eaux dures et appareil pour la mise en ×uvre dudit procede
EP0680932A2 (fr) * 1994-05-06 1995-11-08 United Kingdom Atomic Energy Authority Désionisation électrolytique

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN vol. 014, no. 220 (C - 0717) 10 May 1990 (1990-05-10) *

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1056685A4 (fr) * 1998-02-17 2001-04-18 Potable Water Systems Ldt Cellule electrolytique avec membranes poreuses permettant de concentrer les anions
DE19832822A1 (de) * 1998-07-21 2000-03-09 Sterff Beteiligungsgesellschaf Verfahren und Vorrichtung zur kapazitiven Demineralisierung von Ionen enthaltenden Flüssigkeiten
DE10002733A1 (de) * 2000-01-22 2001-07-26 Bwt Privatstiftung Hintersee Elektrolysezelle und Elektrolyseverfahren
WO2003042112A1 (fr) * 2001-11-13 2003-05-22 Radical Waters (Ip) (Pty) Limited Carbone active electrochimiquement et solutions de sel de bicarbonate
DE102012101031B4 (de) 2012-02-08 2019-02-14 Perma-Trade Wassertechnik Gmbh Verfahren zur Vermeidung von Kalkansatz

Also Published As

Publication number Publication date
EP0951448A1 (fr) 1999-10-27

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