WO2023208731A1 - Wastewater treatment by way of electrocoagulation - Google Patents

Wastewater treatment by way of electrocoagulation Download PDF

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Publication number
WO2023208731A1
WO2023208731A1 PCT/EP2023/060323 EP2023060323W WO2023208731A1 WO 2023208731 A1 WO2023208731 A1 WO 2023208731A1 EP 2023060323 W EP2023060323 W EP 2023060323W WO 2023208731 A1 WO2023208731 A1 WO 2023208731A1
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WIPO (PCT)
Prior art keywords
central space
electrocoagulation
cylindrical central
agitator
electrodes
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PCT/EP2023/060323
Other languages
German (de)
French (fr)
Inventor
Thomas Weimer
Ehsan JAFARI
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Spiraltec Gmbh
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Publication of WO2023208731A1 publication Critical patent/WO2023208731A1/en

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    • 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
    • C02F1/461—Treatment of water, waste water, or sewage by electrochemical methods by electrolysis
    • C02F1/463—Treatment of water, waste water, or sewage by electrochemical methods by electrolysis by electrocoagulation
    • 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
    • C02F2001/007—Processes including a sedimentation step
    • 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
    • C02F1/461—Treatment of water, waste water, or sewage by electrochemical methods by electrolysis
    • C02F1/46104—Devices therefor; Their operating or servicing
    • C02F1/46109—Electrodes
    • C02F2001/46152—Electrodes characterised by the shape or form
    • C02F2001/46171—Cylindrical or tubular shaped
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2101/00—Nature of the contaminant
    • C02F2101/10—Inorganic compounds
    • C02F2101/101—Sulfur compounds
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2101/00—Nature of the contaminant
    • C02F2101/10—Inorganic compounds
    • C02F2101/20—Heavy metals or heavy metal compounds
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2101/00—Nature of the contaminant
    • C02F2101/10—Inorganic compounds
    • C02F2101/20—Heavy metals or heavy metal compounds
    • C02F2101/22—Chromium or chromium compounds, e.g. chromates
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2101/00—Nature of the contaminant
    • C02F2101/30—Organic compounds
    • C02F2101/308—Dyes; Colorants; Fluorescent agents
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2101/00—Nature of the contaminant
    • C02F2101/30—Organic compounds
    • C02F2101/32—Hydrocarbons, e.g. oil
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2101/00—Nature of the contaminant
    • C02F2101/30—Organic compounds
    • C02F2101/32—Hydrocarbons, e.g. oil
    • C02F2101/325—Emulsions
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2101/00—Nature of the contaminant
    • C02F2101/30—Organic compounds
    • C02F2101/34—Organic compounds containing oxygen
    • C02F2101/345—Phenols
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2103/00—Nature of the water, waste water, sewage or sludge to be treated
    • C02F2103/16—Nature of the water, waste water, sewage or sludge to be treated from metallurgical processes, i.e. from the production, refining or treatment of metals, e.g. galvanic wastes
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2103/00—Nature of the water, waste water, sewage or sludge to be treated
    • C02F2103/30—Nature of the water, waste water, sewage or sludge to be treated from the textile industry
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2103/00—Nature of the water, waste water, sewage or sludge to be treated
    • C02F2103/32—Nature of the water, waste water, sewage or sludge to be treated from the food or foodstuff industry, e.g. brewery waste waters
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2103/00—Nature of the water, waste water, sewage or sludge to be treated
    • C02F2103/34—Nature of the water, waste water, sewage or sludge to be treated from industrial activities not provided for in groups C02F2103/12 - C02F2103/32
    • C02F2103/36—Nature of the water, waste water, sewage or sludge to be treated from industrial activities not provided for in groups C02F2103/12 - C02F2103/32 from the manufacture of organic compounds
    • C02F2103/365—Nature of the water, waste water, sewage or sludge to be treated from industrial activities not provided for in groups C02F2103/12 - C02F2103/32 from the manufacture of organic compounds from petrochemical industry (e.g. refineries)
    • 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
    • C02F2201/002—Construction details of the apparatus
    • C02F2201/003—Coaxial constructions, e.g. a cartridge located coaxially within another
    • 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
    • C02F2201/4611—Fluid flow
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2301/00—General aspects of water treatment
    • C02F2301/02—Fluid flow conditions
    • C02F2301/026—Spiral, helicoidal, radial
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2303/00—Specific treatment goals
    • C02F2303/12—Prevention of foaming

Definitions

  • the present invention relates to devices and methods for wastewater treatment by electrocoagulation.
  • Electrocoagulation is an electrochemical technology for the treatment of water and wastewater through the in-situ generation of metal coagulants through electrolytic dissolution of anode materials, triggered by the electric current applied across the electrodes.
  • the metal ions formed from the anode preferably Fe or Al ions, form insoluble compounds in the electrolyte with the OH ions formed at the cathode in aqueous solutions, which then act as coagulants.
  • electrocoagulation does not result in wastewater with an increased salt content.
  • EC is successfully used to remove impurities from aqueous solutions.
  • Typical contaminants are organic substances, sulfur and phenols, dyes, other suspended solids, emulsified oil and heavy metals.
  • a conventional apparatus for electrocoagulation is described in US 8,133,382 B2.
  • the apparatus includes a plurality of spaced apart rectangular reaction plates disposed within a reaction chamber. A voltage is applied to selected reaction plates to create an electric field within the electrocoagulation chamber. The plates are arranged vertically, thereby inducing a vertical flow of liquid through a device.
  • WO 2009/009 465 A1 discloses an electrocoagulation reactor and water purification systems and methods using the reactor.
  • the electrocoagulation reactor has a spiral wound arrangement in which the electrocoagulation treatment takes place.
  • the spirally wound assembly includes electrode sheets that are spaced apart and spirally wound with an area for fluid flow in the space between the electrode sheets.
  • the WO 2021/034 580 A2 relates to iron electrocoagulation reactors (Fe-EC) for removing impurities from water, consisting of an arrangement of folded or spirally wound iron-containing anode and cathode plates, which are separated by perforated insulating spacers.
  • An oxidizing agent can be added to the contaminated water to accelerate the oxidation of Fe(II) ions released from the anode and/or to oxidize the contaminant.
  • both reactors the fluid to be treated flows through the spirals formed by the electrodes in the axial direction, which makes it difficult to ensure a uniform flow through the channels.
  • Both reactors are only suitable for the treatment of slightly contaminated fluids that do not tend to form foam and have very low solids precipitation.
  • an electrocoagulation reactor in which two essentially parallel plates are arranged spirally coaxially, so that fluid entering the innermost cylindrical region follows a spiral path outwards and then upon reaching an outermost cylindrical one Area is directed along a spiral path between the two plates back to the innermost cylindrical area.
  • the spiral-shaped flow channels are connected at the bottom and top by the electrodes. sealed, so that this reactor is also not suitable for the treatment of heavily contaminated wastewater, which tends to foam and form large amounts of solids.
  • the invention has set itself the task of providing a device and a method for electrocoagulation even for heavily contaminated fluids/wastewater, which have a high degree of separation and a low energy requirement and a good and rapid mixing of the coagulants produced with the impurities cause.
  • Figure 1 shows two perspective views of an embodiment of the device according to the invention
  • Figure 2 shows the voltage curve over time in a device according to the invention and an electrocoagulation reactor of the prior art
  • Figure 3 shows a comparison of the foam development in a device according to the invention and an electrocoagulation reactor of the prior art
  • Figure 4 shows the voltage curve over time in a device according to the invention at different stirring speeds
  • Figure 5 shows a comparison of the sedimentation of flakes produced in a device according to the invention and in a prior art electrocoagulation reactor after a standing time of 15 minutes;
  • Figure 6 shows a top view of a further embodiment of the device according to the invention.
  • Figure 7 shows a side view of the device from Figure 6;
  • Figure 8 shows a top view of another embodiment of the device according to the invention
  • Figure 9 shows a top view of an embodiment of the device according to the invention with multiple electrodes.
  • a device for electrocoagulation is provided with spirally wound electrodes which are arranged in a preferably cylindrical central space, the longitudinal axis of the central space forming the central axis of the spirals.
  • the electrodes include spirally wound cathode and anode electrode sheets spaced apart from each other.
  • the fluid to be treated flows radially through the spiral channels, which ensures a uniform flow even with several electrodes, and the channels are open in the axial direction in order to ensure that the channels are blocked by foam and solid flakes, even with heavily loaded fluids impede.
  • a method for electrocoagulation using the device according to the invention is provided.
  • the spaces between the electrode sheets are filled with the liquid to be treated.
  • coagulants are generated electrochemically while the liquid flows radially in the channels of the device according to the invention.
  • the coagulants produced cause the impurities contained in the liquid to flocculate, which can then be easily separated off.
  • the subject of the invention is a device for electrocoagulation, which comprises spirally wound electrode sheets for cathode(s) and anode(s), which are arranged at a distance from one another in a preferably cylindrical central space, the longitudinal axis of the central space forming the central axis of the spirals.
  • the channels formed between the electrode sheets are opened in the axial direction to ensure safe operation also with wastewater. This reliably prevents the channels from becoming blocked by foam and solid flakes, even with heavily loaded fluids, since the differences in density mean that they emerge upwards or downwards from the spiral channels.
  • the fluid to be treated flows radially through the spiral channels, which ensures a uniform flow even with several electrodes.
  • the cylindrical central space is bounded at the bottom by a floor which is spaced apart from the spirals in order to ensure that solids formed are transported downwards from the spiral channels.
  • the cylindrical central space has at least one liquid inlet.
  • the liquid inlet is arranged near the lower end of the cylinder.
  • the cylindrical central space has at least one liquid outlet.
  • the liquid outlet is arranged near the upper end of the cylinder.
  • the upper end of the cylindrical central space is open so that liquid can exit over the upper edge of the cylindrical central space.
  • the cylindrical central space is bounded at the top by a cover, which is then also spaced from the spirals in order to ensure that foams formed are removed from the spiral channels.
  • the wall of the cylindrical central space is made of plastic. Since there are usually corrosive chemicals and gases in the liquid to be treated, the material of the container should be corrosion-resistant.
  • suitable plastics are polypropylene (PP), polyethylene (PE), or polyvinyl chloride (PVC).
  • the plastic is polycarbonate or polymethyl methacrylate (“Plexiglass").
  • the device according to the invention there are at least two electrodes, alternating anode and cathode, in the form of at least two combined ned Archimedean spirals are wound in such a way that spiral-shaped flow channels are formed between the anodes and cathodes, through which liquid flows radially during operation.
  • the radial flow is generated by at least one agitator arranged in the cylindrical central space.
  • an agitator is arranged above the electrodes.
  • an agitator is arranged below the electrodes.
  • a cylindrical area is kept free in the core of the spirals, in which there is at least one agitator.
  • a combination of agitators is also possible. When the agitator is arranged under the electrodes, the flakes formed are not damaged by the agitator. A particularly good flow through the spiral channels and good separation performance are achieved with a central agitator below the spiral body.
  • the at least one agitator has a significant influence on the effectiveness of the removal of contaminants and the energy consumption in the device.
  • the increase in stress during operation is significantly lower than in a device without an agitator, the flakes formed are much larger and can be separated more easily, and a significantly higher proportion of the impurities are removed.
  • the device according to the invention is operated in batch operation. In a further development of the device according to the invention, it is intended for continuous operation and has at least one liquid inlet and at least one liquid outlet, which are arranged at a distance from one another, for example opposite one another on the jacket of the cylindrical central space or near the upper and lower ends of the cylindrical central room.
  • an agitator is optional.
  • the anode contains metallic iron, aluminum, or titanium. In a further embodiment, the anode consists of metallic iron, steel, aluminum, or titanium. In a further embodiment, the anode and cathode are made of the same material. In another embodiment, the anode and cathode are made of different materials. In a further embodiment, the cathode contains graphite or metallic copper.
  • the anode is a consumable part that needs to be replaced from time to time, iron and aluminum are the most important materials due to their availability.
  • the material of the sacrificial anode also depends on the pH and the type of impurities. For example, if the pH is above 9, an iron electrode is preferred. If the pH value is between 5 and 8, an Al electrode is suitable.
  • the device has a cylindrical outer space arranged coaxially to the cylindrical central space, which has a larger diameter than the cylindrical central space and which is designed to receive liquid emerging from the head of the cylindrical central space.
  • the cylindrical outer space forms a collar around the cylindrical central space. This collar serves to collect the foams that may be formed.
  • the length of the cylindrical outer space is smaller than the length of the cylindrical central space.
  • the cylindrical outer space is arranged around the cylindrical central space such that the upper edge of the cylindrical outer space is at the same height as the upper edge of the cylindrical central space.
  • the wall of the cylindrical outer space is made of corrosion-resistant plastic, which enables the treatment of acidic or basic solutions.
  • the plastic is polypropylene or PVC.
  • the invention also relates to a method for treating water (feed) containing impurities by electrocoagulation.
  • the water containing impurities is filled into a device according to the invention.
  • the water containing impurities is continuously circulated in the device by the at least one agitator.
  • a direct voltage is applied to the electrodes and an electrical current is passed through the device, electrochemically producing metal hydroxides that cause the contaminants to flocculate.
  • the flocculated impurities are then separated off.
  • the contaminants are sent to a settling tank after treatment with EC. Since flakes settle due to their high density, they can be disposed of without filtration. The settling time depends on the concentration of impurities in the feed, but is usually between 10 and 30 minutes. The rest goes to a filtration process.
  • Some parameters of the method according to the invention depend on the quality of the feed and are set according to the concentration of impurities in the feed.
  • the pH value of the feed is from pH 3 to pH 12.
  • the ratio (S/V) of the electrode surface (S) to the volume of the feed (V) is 0.5 to 0, 7.
  • the electrode surface (S) is 700 to 900 cm 2 .
  • the speed is the at least one agitator from 100 to 800 rpm, for example from 200 to 600 rpm, in particular from 400 to 500 rpm.
  • the impurities contained in the water include organic substances.
  • the contaminants contained in the water include phenols.
  • the contaminants contained in the water include sulfur.
  • the contaminants contained in the water include dye particles.
  • the contaminants contained in the water include suspended solids.
  • the impurities contained in the water include emulsified oil.
  • the impurities contained in the water include (heavy) metals or metalloids, for example copper, zinc, chromium, cadmium or silicon.
  • the device according to the invention and the method according to the invention are particularly suitable for use in oil refineries and the petrochemical industry, in the food industry, the metal industry and the textile industry.
  • Electrolysis takes place at the cathode electrode, which leads to the formation of gas bubbles, which can adhere to the electrode surface if the flow is poor and cause considerable additional resistance and voltage. cause an increase in voltage. Due to the round cross section of the cylindrical central space, the at least one agitator works very effectively and achieves a uniform flow over the electrode surfaces in the spiral channels, which leads to an improvement in the electrolysis efficiency. Due to the shape of the electrodes, the flow velocity on the surface of the electrodes is high and the liquid is thoroughly mixed, which leads to less foam formation. A removal efficiency of more than 90 percent is achieved for solids, emulsified oil and (semi-)metals, such as copper, chromium, lead, mercury or silicon.
  • the solution according to the invention offers numerous advantages compared to conventional EC systems with plate electrodes: lower energy requirements due to the removal of passivation by the flow pattern; a smaller space requirement by integrating three processes (electrocoagulation, electroflotation and sedimentation) into one system; a shorter treatment time due to the good mixing of coagulants and impurities; a lower filtration effort due to the large flocs formed and less foam formation due to the higher speed of the flow surface.
  • Figure 1 shows two perspective views of an embodiment of the device 10 according to the invention.
  • the left figure shows a side view
  • the right figure shows a view obliquely from above.
  • a cylindrical central space 11 of the device 10 is made of a transparent plastic and is open at the upper end.
  • a cylindrical outer space 12 is arranged around the cylindrical central space 11, which forms a collar of the cylindrical central space 11 and is also made of transparent plastic.
  • the cylindrical central space 11 has a liquid supply 13 near its lower end, the cylindrical outer space 12 has a liquid discharge 14 near its upper edge.
  • spirally curved electrode sheets 15 are arranged in the form of two combined Archimedean spirals in such a way that spiral-shaped flow channels are formed between the anode and cathode. The spirals 15 are arranged at a distance from the bottom 17 of the cylindrical central space 11.
  • test conditions are summarized in Tables 1 -3.
  • a halogen-free processing emulsion with an oil content of 8% by weight and a solids content of ⁇ 5% by weight, pH 9.0, containing 136 mg/l ammonium, ⁇ 2 mg/l cadmium, 2 mg/l was used as feed Lead, 7 mg/l copper, 13 mg/l zinc, 6 mq/l chromium, 0.076 wt.% sulfur, 921 mq/l phosphorus, 2,182 mq/l aluminum and 1,800 mq/l silicon.
  • Figure 2 shows the voltage curve over time in the device according to the invention (solid line) and the prior art electrocoagulation reactor (dashed line).
  • the respective operating times were selected according to the impurity concentration in the feed. Higher concentrations require longer operating time. The different output voltages are also due to the concentration differences.
  • Table 3 The two electrocoagulation devices, whose electrodes each consisted of aluminum sheets with an area of 836 cm 2 , were each filled with 1300 ml of liquid in all experiments and a current of 5 A was passed through the device for the respective period of time.
  • the feed concentration was adjusted by mixing appropriate volumes of water with the feed.
  • the agitator was operated at a stirrer speed of 400 rpm in order to allow the liquid to circulate continuously in the device.
  • the conductivity of the liquid, its pH value, the liquid temperature and the applied voltage were measured at the beginning of the experiment (Start) and after the end of the experiment (End).
  • the device according to the invention has a significantly lower voltage requirement and thus a reduced energy requirement for the same current strength than the device of the prior art.
  • Figure 3 shows the foam development in the device according to the invention (left row) and the electrocoagulation reactor of the prior art (right row) in comparison after 5, 10, 15 and 20 minutes of operation.
  • the prior art device in the prior art device a large volume of foam was generated on the liquid surface. This indicates that the plate electrodes act as a barrier for good mixing of Al ions and OH ions for the production of coagulants as well as for the mixing of the produced coagulants with the impurities, which leads to lower separation efficiency and thus foam formation during stirring .
  • the speed on the surface is high due to the spiral configuration, which leads to good mixing and negligible foam formation and thus higher efficiency.
  • Figure 4 shows the voltage curve over time in the device according to the invention at the different stirring speeds.
  • the results of the experiments show that stirring during electrocoagulation (EC) has an important influence on the removal of impurities and energy consumption.
  • the experiments show that the increase in voltage during EC without stirring is approximately three times greater than with stirring.
  • the impurity removal efficiency (measured by the turbidity of the liquid) at EC with stirring speeds of 400 to 500 rpm is 82-90%, while only 56% is achieved without stirring.
  • FIG. 5 shows a comparison of the sedimentation of the flocs formed by EC 15 min after the end of the EC treatment, on the left (a) liquid treated by EC with stirring and on the right (b) liquid treated by EC without stirring.
  • Figure 6 shows a top view of a further embodiment of a device 20 according to the invention;
  • Figure 7 shows a side view of the device 20.
  • the batch reactor 20 is mounted on a frame 29 and 20 has an inlet 21 with an inlet valve 22 for supplying liquid to be treated into the batch reactor 20.
  • An agitator 24 is attached to a stirrer holder 23 and is driven by an electric motor 25 powered.
  • Inside the batch reactor 20 there are spiral-shaped aluminum electrodes 26.
  • At the lowest point of the batch reactor 20 there is a drain 28 with an outlet valve 27, via which the batch reactor 20 can be emptied.
  • FIG. 9 shows a top view of an embodiment of the device 40 according to the invention with several electrodes 41, 42.
  • several cathodes 41 and anodes 42 are arranged alternately so that they do not touch each other.
  • the individual sheets of the cathodes 41 and anodes 42 are each bent in such a way that all electrodes 41, 42 together form a vortex.
  • the axis of an agitator 43 runs along the central axis of the device 40, the blades of which are arranged below the electrodes 41, 42.

Abstract

The present invention relates to devices (10) and methods for wastewater treatment by way of electrocoagulation. The devices (10) comprise spirally wound electrode sheets (15) for the cathode and the anode and at least one stirrer (16) below the electrodes (15).

Description

Abwasserreinigung durch Elektrokoagulation Wastewater treatment by electrocoagulation
Technisches Gebiet Technical area
Die vorliegende Erfindung betrifft Vorrichtungen und Verfahren zur Abwasserreinigung durch Elektrokoagulation. The present invention relates to devices and methods for wastewater treatment by electrocoagulation.
Beschreibung des Standes der Technik Description of the prior art
Die Elektrokoagulation (EC = Electrocoagulation) ist eine elektrochemische Technologie zur Behandlung von Wasser und Abwasser durch die in-situ- Erzeugung von Metallkoagulantien durch elektrolytische Auflösung von Anodenmaterialien, ausgelöst durch den über die Elektroden angelegten elektrischen Strom. Die aus der Anode gebildeten Metallionen, vorzugsweise Fe- oder Al-Ionen, bilden im Elektrolyten mit den an der Kathode gebildeten OH- Ionen in wässrigen Lösungen unlösliche Verbindungen, die dann als Koagulantien wirken. Im Gegensatz zur chemischen Koagulation durch Zugabe von löslichen Fe- oder Al-Salzen resultiert bei der Elektrokoagulation kein Abwasser mit erhöhtem Salzgehalt. Electrocoagulation (EC = Electrocoagulation) is an electrochemical technology for the treatment of water and wastewater through the in-situ generation of metal coagulants through electrolytic dissolution of anode materials, triggered by the electric current applied across the electrodes. The metal ions formed from the anode, preferably Fe or Al ions, form insoluble compounds in the electrolyte with the OH ions formed at the cathode in aqueous solutions, which then act as coagulants. In contrast to chemical coagulation by adding soluble Fe or Al salts, electrocoagulation does not result in wastewater with an increased salt content.
EC wird erfolgreich zur Entfernung von Verunreinigungen aus wässrigen Lösungen eingesetzt. Typische Verunreinigungen sind organische Stoffe, Schwefel und Phenole, Farbstoffe, sonstige Schwebstoffe, emulgiertes Öl und Schwermetalle. EC is successfully used to remove impurities from aqueous solutions. Typical contaminants are organic substances, sulfur and phenols, dyes, other suspended solids, emulsified oil and heavy metals.
Ein konventioneller Apparat zur Elektrokoagulation ist in US 8 133 382 B2 beschrieben. Die Vorrichtung umfasst eine Vielzahl von beabstandeten rechteckigen Reaktionsplatten, die innerhalb einer Reaktionskammer angeordnet sind. An ausgewählte Reaktionsplatten wird eine Spannung angelegt, um ein elektrisches Feld innerhalb der Elektrokoagulationskammer zu erzeugen. Die Platten sind vertikal angeordnet, wodurch ein vertikaler Flüssigkeitsstrom durch eine Vorrichtung induziert wird. A conventional apparatus for electrocoagulation is described in US 8,133,382 B2. The apparatus includes a plurality of spaced apart rectangular reaction plates disposed within a reaction chamber. A voltage is applied to selected reaction plates to create an electric field within the electrocoagulation chamber. The plates are arranged vertically, thereby inducing a vertical flow of liquid through a device.
Die WO 2009 / 009 465 A1 offenbart einen Elektrokoagulationsreaktor und Wasserreinigungssysteme und -verfahren, die den Reaktor verwenden. Der Elektrokoagulationsreaktor hat eine spiralförmig gewickelte Anordnung, in der die Elektrokoagulationsbehandlung stattfindet. Die spiralförmig gewickelte Anordnung umfasst Elektrodenblätter, die mit Abstand voneinander spiralförmig gewickelt sind, mit einem Bereich für Fluidströmung in dem Raum zwischen den Elektrodenblättern. WO 2009/009 465 A1 discloses an electrocoagulation reactor and water purification systems and methods using the reactor. The electrocoagulation reactor has a spiral wound arrangement in which the electrocoagulation treatment takes place. The spirally wound assembly includes electrode sheets that are spaced apart and spirally wound with an area for fluid flow in the space between the electrode sheets.
Die WO 2021 / 034 580 A2 betrifft Eisen-Elektrokoagulationsreaktoren (Fe-EC) zum Entfernen von Verunreinigungen aus Wasser, bestehend aus einer Anordnung von gefalteten oder spiralförmig gewickelten eisenhaltigen Anoden- und Kathodenplatten, die durch perforierte isolierende Abstandshalter getrennt sind. Dem verunreinigten Wasser kann ein Oxidationsmittel zugesetzt werden, um die Oxidation von aus der Anode freigesetzten Fe(ll)-Ionen zu beschleunigen und/oder die Verunreinigung zu oxidieren. The WO 2021/034 580 A2 relates to iron electrocoagulation reactors (Fe-EC) for removing impurities from water, consisting of an arrangement of folded or spirally wound iron-containing anode and cathode plates, which are separated by perforated insulating spacers. An oxidizing agent can be added to the contaminated water to accelerate the oxidation of Fe(II) ions released from the anode and/or to oxidize the contaminant.
Das zu behandelnde Fluid durchströmt bei beiden Reaktoren die durch die Elektroden gebildeten Spiralen in axialer Richtung, wodurch eine gleichmäßige Durchströmung der Kanäle schwierig zu gewährleisten ist. Beide Reaktoren sind nur für die Behandlung von schwach belasteten Fluiden geeignet, die nicht zur Schaumbildung neigen und nur einen sehr geringen Feststoff ausfall aufweisen. In both reactors, the fluid to be treated flows through the spirals formed by the electrodes in the axial direction, which makes it difficult to ensure a uniform flow through the channels. Both reactors are only suitable for the treatment of slightly contaminated fluids that do not tend to form foam and have very low solids precipitation.
Aus der WO 2004 / 089 832 A1 ist ein Elektrokoagulationsreaktor bekannt, in dem zwei im Wesentlichen parallele Platten spiralförmig koaxial angeordnet sind, so dass Fluid, das in den innersten zylindrischen Bereich eintritt, einem spiralförmigen Weg nach außen folgt und dann beim Erreichen eines äußersten zylindrischen Bereichs entlang einem spiralförmigen Weg zwischen den zwei Platten geleitet wird zurück zum innersten zylindrischen Bereich. Hierbei sind die spiralförmigen Strömungskanäle unten und oben durch die Elektroden ab- gedichtet, so dass auch dieser Reaktor nicht geeignet für die Behandlung von stark belasteten Abwässern ist, die zur Schaumbildung neigen und große Mengen an Feststofflocken bilden. From WO 2004/089 832 A1 an electrocoagulation reactor is known in which two essentially parallel plates are arranged spirally coaxially, so that fluid entering the innermost cylindrical region follows a spiral path outwards and then upon reaching an outermost cylindrical one Area is directed along a spiral path between the two plates back to the innermost cylindrical area. The spiral-shaped flow channels are connected at the bottom and top by the electrodes. sealed, so that this reactor is also not suitable for the treatment of heavily contaminated wastewater, which tends to foam and form large amounts of solids.
Aufgabe der Erfindung Task of the invention
Vor diesem Hintergrund hat sich die Erfindung die Aufgabe gestellt, eine Vorrichtung und ein Verfahren zur Elektrokoagulation auch für stark belastete Flui- de/Abwässer bereitzustellen, die einen hohen Abscheidegrad und einen geringen Energiebedarf aufweisen und eine gute und schnelle Vermischung der produzierten Koagulantien mit den Verunreinigungen bewirken. Against this background, the invention has set itself the task of providing a device and a method for electrocoagulation even for heavily contaminated fluids/wastewater, which have a high degree of separation and a low energy requirement and a good and rapid mixing of the coagulants produced with the impurities cause.
Kurzbeschreibung der Abbildungen Short description of the images
Figur 1 zeigt zwei perspektivische Ansichten einer Ausführungsform der erfindungsgemäßen Vorrichtung; Figure 1 shows two perspective views of an embodiment of the device according to the invention;
Figur 2 zeigt den Spannungsverlauf über die Zeit in einer erfindungsgemäßen Vorrichtung und einem Elektrokoagulationsreaktor des Standes der Technik; Figure 2 shows the voltage curve over time in a device according to the invention and an electrocoagulation reactor of the prior art;
Figur 3 zeigt einen Vergleich der Schaumentwicklung in einer erfindungsgemäßen Vorrichtung und einem Elektrokoagulationsreaktor des Standes der Technik; Figure 3 shows a comparison of the foam development in a device according to the invention and an electrocoagulation reactor of the prior art;
Figur 4 zeigt den Spannungsverlauf über die Zeit in einer erfindungsgemäßen Vorrichtung bei verschiedenen Rührgeschwindigkeiten; Figure 4 shows the voltage curve over time in a device according to the invention at different stirring speeds;
Figur 5 zeigt einen Vergleich der Sedimentation von in einer erfindungsgemäßen Vorrichtung und in einem Elektrokoagulationsreaktor des Standes der Technik produzierten Flocken nach 15 min Standzeit;Figure 5 shows a comparison of the sedimentation of flakes produced in a device according to the invention and in a prior art electrocoagulation reactor after a standing time of 15 minutes;
Figur 6 zeigt eine Aufsicht einer weiteren Ausführungsform der erfindungsgemäßen Vorrichtung; Figure 6 shows a top view of a further embodiment of the device according to the invention;
Figur 7 zeigt eine Seitenansicht der Vorrichtung aus Figur 6; Figure 7 shows a side view of the device from Figure 6;
Figur 8 zeigt eine Aufsicht einer anderen Ausführungsform der erfindungsgemäßen Vorrichtung; Figur 9 zeigt eine Aufsicht einer Ausführungsform der erfindungsgemäßen Vorrichtung mit mehreren Elektroden. Figure 8 shows a top view of another embodiment of the device according to the invention; Figure 9 shows a top view of an embodiment of the device according to the invention with multiple electrodes.
Zusammenfassung Summary
Es wird eine Vorrichtung zur Elektrokoagulation mit spiralförmig gewickelten Elektroden bereitgestellt, die in einem vorzugsweise zylinderförmigen Zentralraum angeordnet sind, wobei die Längsachse des Zentralraums die Mittelachse der Spiralen bildet. Die Elektroden umfassen spiralförmig gewickelte Elektrodenblätter für Kathode und Anode, die mit Abstand voneinander angeordnet sind. Das zu behandelnde Fluid strömt radial durch die spiralförmigen Kanäle, wodurch auch bei mehreren Elektroden eine gleichmäßige Durchströmung gewährleistet ist, und die Kanäle sind in axialer Richtung offen, um auch bei stark belasteten Fluiden eine Verblockung der Kanäle durch Schaum und gebildete Feststoff-Flocken sicher zu verhindern. A device for electrocoagulation is provided with spirally wound electrodes which are arranged in a preferably cylindrical central space, the longitudinal axis of the central space forming the central axis of the spirals. The electrodes include spirally wound cathode and anode electrode sheets spaced apart from each other. The fluid to be treated flows radially through the spiral channels, which ensures a uniform flow even with several electrodes, and the channels are open in the axial direction in order to ensure that the channels are blocked by foam and solid flakes, even with heavily loaded fluids impede.
Außerdem wird ein Verfahren zur Elektrokoagulation mit der erfindungsgemäßen Vorrichtung zur Verfügung gestellt. Die Zwischenräume zwischen den Elektrodenblättern sind mit der zu behandelnden Flüssigkeit gefüllt. Durch Anlegen einer Gleichspannung an die Elektroden werden elektrochemisch Koagu- lantien erzeugt, während die Flüssigkeit radial in den Kanälen der erfindungsgemäßen Vorrichtung strömt. Die erzeugten Koagulantien bewirken ein Ausflocken der in der Flüssigkeit enthaltenen Verunreinigungen, die anschließend leicht abgetrennt werden können. In addition, a method for electrocoagulation using the device according to the invention is provided. The spaces between the electrode sheets are filled with the liquid to be treated. By applying a direct voltage to the electrodes, coagulants are generated electrochemically while the liquid flows radially in the channels of the device according to the invention. The coagulants produced cause the impurities contained in the liquid to flocculate, which can then be easily separated off.
Detaillierte Beschreibung Detailed description
Gegenstand der Erfindung ist eine Vorrichtung zur Elektrokoagulation, welche spiralförmig gewickelte Elektrodenblätter für Kathode(n) und Anode(n) umfasst, die beabstandet voneinander in einem vorzugsweise zylinderförmigen Zentralraum angeordnet sind, wobei die Längsachse des Zentralraums die Mittelachse der Spiralen bildet. Erfindungsgemäß sind die zwischen den Elektrodenblättern ausgebildeten Kanäle in axialer Richtung geöffnet, um einen sicheren Betrieb auch mit Abwässern zu gewährleisten. Eine Verblockung der Kanäle durch Schaum und gebildete Feststoff-Flocken wird dadurch auch bei stark belasteten Fluiden sicher verhindert, da aufgrund der Dichteunterschiede diese nach oben bzw. unten aus den Spiralkanälen austreten. Das zu behandelnde Fluid strömt radial durch die spiralförmigen Kanäle, wodurch auch bei mehreren Elektroden eine gleichmäßige Durchströmung gewährleistet ist. The subject of the invention is a device for electrocoagulation, which comprises spirally wound electrode sheets for cathode(s) and anode(s), which are arranged at a distance from one another in a preferably cylindrical central space, the longitudinal axis of the central space forming the central axis of the spirals. According to the invention, the channels formed between the electrode sheets are opened in the axial direction to ensure safe operation also with wastewater. This reliably prevents the channels from becoming blocked by foam and solid flakes, even with heavily loaded fluids, since the differences in density mean that they emerge upwards or downwards from the spiral channels. The fluid to be treated flows radially through the spiral channels, which ensures a uniform flow even with several electrodes.
Der zylinderförmige Zentralraum ist nach unten durch einen Boden begrenzt, der von den Spiralen beabstandet ist, um einen Abtransport von gebildeten Feststoffen aus den Spiralkanälen nach unten zu gewährleisten. In einer Ausführungsform der Vorrichtung weist der zylinderförmige Zentralraum mindestens einen Flüssigkeitseinlass auf. In einer weiteren Ausführungsform ist der Flüssigkeitseinlass nahe des unteren Endes des Zylinders angeordnet. In einer Ausführungsform weist der zylinderförmige Zentralraum mindestens einen Flüssigkeitsauslass auf. In einer weiteren Ausführungsform ist der Flüssigkeitsauslass nahe des oberen Endes des Zylinders angeordnet. The cylindrical central space is bounded at the bottom by a floor which is spaced apart from the spirals in order to ensure that solids formed are transported downwards from the spiral channels. In one embodiment of the device, the cylindrical central space has at least one liquid inlet. In a further embodiment, the liquid inlet is arranged near the lower end of the cylinder. In one embodiment, the cylindrical central space has at least one liquid outlet. In a further embodiment, the liquid outlet is arranged near the upper end of the cylinder.
In einer Ausführungsform ist das obere Ende des zylinderförmigen Zentralraums offen, so dass Flüssigkeit über den oberen Rand des zylinderförmigen Zentralraums austreten kann. In einer anderen Ausführungsform ist der zylinderförmige Zentralraum nach oben durch einen Deckel begrenzt, der dann ebenfalls von den Spiralen beabstandet ist, um einen Abtransport von gebildeten Schäumen aus den Spiralkanälen zu gewährleisten. In one embodiment, the upper end of the cylindrical central space is open so that liquid can exit over the upper edge of the cylindrical central space. In another embodiment, the cylindrical central space is bounded at the top by a cover, which is then also spaced from the spirals in order to ensure that foams formed are removed from the spiral channels.
In einer Ausführungsform besteht die Wand des zylinderförmigen Zentralraums aus Kunststoff. Da sich in der Regel korrosive Chemikalien und Gase in der zu behandelnden Flüssigkeit befinden, sollte das Material des Behälters korrosionsbeständig sein. Beispiele geeigneter Kunststoffe sind Polypropylen (PP), Polyethylen (PE), oder Polyvinylchlorid (PVC). In einer weiteren Ausführungsform ist der Kunststoff Polycarbonat oder Polymethylmethacrylat ("Plexiglas"). In one embodiment, the wall of the cylindrical central space is made of plastic. Since there are usually corrosive chemicals and gases in the liquid to be treated, the material of the container should be corrosion-resistant. Examples of suitable plastics are polypropylene (PP), polyethylene (PE), or polyvinyl chloride (PVC). In a further embodiment, the plastic is polycarbonate or polymethyl methacrylate ("Plexiglass").
In der erfindungsgemäßen Vorrichtung sind mindestens zwei Elektroden, abwechselnd jeweils Anode und Kathode, in Form von mindestens zwei kombi- nierten archimedischen Spiralen derart gewickelt, dass zwischen Anoden und Kathoden spiralförmige Strömungskanäle ausgebildet sind, die im Betrieb radial mit Flüssigkeit durchströmt werden. In the device according to the invention there are at least two electrodes, alternating anode and cathode, in the form of at least two combined ned Archimedean spirals are wound in such a way that spiral-shaped flow channels are formed between the anodes and cathodes, through which liquid flows radially during operation.
In einer Ausführungsform der Vorrichtung wird die radiale Strömung durch mindestens ein im zylinderförmigen Zentralraum angeordnetes Rührwerk erzeugt. In einer Ausführungsform der Vorrichtung ist ein Rührwerk oberhalb der Elektroden angeordnet. In einer anderen Ausführungsform der Vorrichtung ist ein Rührwerk unterhalb der Elektroden angeordnet. In wieder einer anderen Ausführungsform der Vorrichtung ist im Kern der Spiralen ein zylindrischer Bereich freigehalten, in dem sich mindestens ein Rührwerk befindet. Auch eine Kombination von Rührwerken ist möglich. Bei Anordnung des Rührwerks unter den Elektroden werden die gebildeten Flocken durch das Rührwerk nicht beschädigt. Eine besonders gute Durchströmung der Spiralkanäle und eine gute Abscheideleistung werden mit einem zentralen Rührwerk unterhalb des Spiralkörpers erreicht. In one embodiment of the device, the radial flow is generated by at least one agitator arranged in the cylindrical central space. In one embodiment of the device, an agitator is arranged above the electrodes. In another embodiment of the device, an agitator is arranged below the electrodes. In yet another embodiment of the device, a cylindrical area is kept free in the core of the spirals, in which there is at least one agitator. A combination of agitators is also possible. When the agitator is arranged under the electrodes, the flakes formed are not damaged by the agitator. A particularly good flow through the spiral channels and good separation performance are achieved with a central agitator below the spiral body.
Das mindestens eine Rührwerk hat einen signifikanten Einfluss auf die Effektivität der Entfernung von Verunreinigungen und den Energieverbrauch in der Vorrichtung. In einer erfindungsgemäßen Vorrichtung mit aktivem Rührwerk ist die Spannungszunahme während des Betriebs erheblich geringer als in einer Vorrichtung ohne Rührwerk, die gebildeten Flocken sind viel größer und können leichter abgetrennt werden, und es wird ein signifikant höherer Anteil der Verunreinigungen entfernt. The at least one agitator has a significant influence on the effectiveness of the removal of contaminants and the energy consumption in the device. In a device according to the invention with an active agitator, the increase in stress during operation is significantly lower than in a device without an agitator, the flakes formed are much larger and can be separated more easily, and a significantly higher proportion of the impurities are removed.
Die erfindungsgemäße Vorrichtung wird im Batchbetrieb betrieben. In einer Weiterbildung der erfindungsgemäßen Vorrichtung ist diese für den kontinuierlichen Betrieb vorgesehen und weist mindestens einen Flüssigkeitseinlass und mindestens einen Flüssigkeitsauslass auf, die beabstandet voneinander angeordnet sind, beispielsweise einander gegenüberliegend auf dem Mantel des zylinderförmigen Zentralraums oder in der Nähe des oberen und unteren Endes des zylinderförmigen Zentralraums. In dieser Ausführungsform ist ein Rührwerk optional. In einer Ausführungsform der Vorrichtung enthält die Anode metallisches Eisen, Aluminium, oder Titan. In einer weiteren Ausführungsform besteht die Anode aus metallischem Eisen, Stahl, Aluminium, oder Titan. In einer weiteren Ausführungsform bestehen Anode und Kathode aus demselben Material. In einer anderen Ausführungsform bestehen Anode und Kathode aus unterschiedlichen Materialien. In einer weiteren Ausführungsform enthält die Kathode Graphit o- der metallisches Kupfer. The device according to the invention is operated in batch operation. In a further development of the device according to the invention, it is intended for continuous operation and has at least one liquid inlet and at least one liquid outlet, which are arranged at a distance from one another, for example opposite one another on the jacket of the cylindrical central space or near the upper and lower ends of the cylindrical central room. In this embodiment, an agitator is optional. In one embodiment of the device, the anode contains metallic iron, aluminum, or titanium. In a further embodiment, the anode consists of metallic iron, steel, aluminum, or titanium. In a further embodiment, the anode and cathode are made of the same material. In another embodiment, the anode and cathode are made of different materials. In a further embodiment, the cathode contains graphite or metallic copper.
Bei der Auswahl der Elektrodenmaterialien sollten zwei Faktoren berücksichtigt werden: erstens die Verfügbarkeit der Metalle und zweitens der pH-Wert des Feeds. Da es sich bei der Anode um ein Verbrauchsteil handelt, das von Zeit zu Zeit ersetzt werden muss, sind Eisen und Aluminium aufgrund ihrer Verfügbarkeit die wichtigsten Materialien. Das Material der Opferanode hängt auch vom pH-Wert und der Art der Verunreinigungen ab. Liegt der pH-Wert beispielsweise über 9, wird eine Eisenelektrode bevorzugt. Liegt der pH-Wert zwischen 5 und 8, ist eine Al-Elektrode geeignet. When selecting electrode materials, two factors should be taken into account: first, the availability of the metals and second, the pH of the feed. Since the anode is a consumable part that needs to be replaced from time to time, iron and aluminum are the most important materials due to their availability. The material of the sacrificial anode also depends on the pH and the type of impurities. For example, if the pH is above 9, an iron electrode is preferred. If the pH value is between 5 and 8, an Al electrode is suitable.
In einer Ausführungsform weist die Vorrichtung einen koaxial zum zylinderförmigen Zentralraum angeordneten zylinderförmigen Außenraum auf, der einen größeren Durchmesser aufweist als der zylinderförmige Zentralraum und der dafür eingerichtet ist, am Kopf des zylinderförmigen Zentralraums austretende Flüssigkeit aufzunehmen. In einer weiteren Ausführungsform bildet der zylinderförmige Außenraum einen Kragen um den zylinderförmigen Zentralraum. Dieser Kragen dient dazu, die möglicherweise gebildeten Schäume zu sammeln. In einer weiteren Ausführungsform ist die Länge des zylinderförmigen Außenraums kleiner als die Länge des zylinderförmigen Zentralraums. In einer weiteren Ausführungsform ist der zylinderförmige Außenraum so um den zylinderförmigen Zentralraum angeordnet, dass sich der obere Rand des zylinderförmigen Außenraums auf gleicher Höhe wie der obere Rand des zylinderförmigen Zentralraums befindet. In einer Ausführungsform besteht die Wand des zylinderförmigen Außenraums aus korrosionsbeständigem Kunststoff, was die Behandlung von sauren oder basischen Lösungen ermöglicht. In einer weiteren Ausführungsform ist der Kunststoff Polypropylen oder PVC. In one embodiment, the device has a cylindrical outer space arranged coaxially to the cylindrical central space, which has a larger diameter than the cylindrical central space and which is designed to receive liquid emerging from the head of the cylindrical central space. In a further embodiment, the cylindrical outer space forms a collar around the cylindrical central space. This collar serves to collect the foams that may be formed. In a further embodiment, the length of the cylindrical outer space is smaller than the length of the cylindrical central space. In a further embodiment, the cylindrical outer space is arranged around the cylindrical central space such that the upper edge of the cylindrical outer space is at the same height as the upper edge of the cylindrical central space. In one embodiment, the wall of the cylindrical outer space is made of corrosion-resistant plastic, which enables the treatment of acidic or basic solutions. In a further embodiment, the plastic is polypropylene or PVC.
Gegenstand der Erfindung ist auch ein Verfahren zur Behandlung von Verunreinigungen enthaltendem Wasser (Feed) durch Elektrokoagulation. Im erfindungsgemäßen Verfahren wird das Verunreinigungen enthaltende Wasser in eine erfindungsgemäße Vorrichtung gefüllt. Das Verunreinigungen enthaltende Wasser wird in der Vorrichtung durch das mindestens eine Rührwerk kontinuierlich umgewälzt. Es wird eine Gleichspannung an die Elektroden angelegt und ein elektrischer Strom durch die Vorrichtung geleitet, wodurch elektrochemisch Metallhydroxide erzeugt werden, die eine Ausflockung der Verunreinigungen bewirken. Die ausgeflockten Verunreinigungen werden anschließend abgetrennt. The invention also relates to a method for treating water (feed) containing impurities by electrocoagulation. In the method according to the invention, the water containing impurities is filled into a device according to the invention. The water containing impurities is continuously circulated in the device by the at least one agitator. A direct voltage is applied to the electrodes and an electrical current is passed through the device, electrochemically producing metal hydroxides that cause the contaminants to flocculate. The flocculated impurities are then separated off.
In einer Ausführungsform des Verfahrens werden die Verunreinigungen nach der Behandlung mit EC in ein Absetzbecken geleitet. Da sich Flocken aufgrund ihrer hohen Dichte absetzen, können sie ohne Filtration entsorgt werden. Die Absetzzeit ist abhängig von der Konzentration der Verunreinigungen im Feed, liegt aber in der Regel zwischen 10 und 30 Minuten. Der Rest fließt einem Filtrationsprozess zu. In one embodiment of the process, the contaminants are sent to a settling tank after treatment with EC. Since flakes settle due to their high density, they can be disposed of without filtration. The settling time depends on the concentration of impurities in the feed, but is usually between 10 and 30 minutes. The rest goes to a filtration process.
Einige Parameter des erfindungsgemäßen Verfahrens (z.B. Betriebszeit oder Stromdichte) hängen von der Qualität des Feeds ab und werden entsprechend der Konzentration an Verunreinigungen im Feed eingestellt. Some parameters of the method according to the invention (e.g. operating time or current density) depend on the quality of the feed and are set according to the concentration of impurities in the feed.
In einer Ausführungsform des Verfahrens beträgt der pH-Wert des Feeds von pH 3 bis pH 12. In einer Ausführungsform des Verfahrens beträgt das Verhältnis (S/V) der Elektrodenoberfläche (S) zum Volumen des Feeds (V) 0,5 bis 0,7. In einer Ausführungsform des Verfahrens beträgt die Elektrodenoberfläche (S) 700 bis 900 cm2. In einer Ausführungsform des Verfahrens beträgt die Drehzahl des mindestens einen Rührwerks von 100 bis 800 U/min, beispielsweise von 200 bis 600 U/min, insbesondere von 400 bis 500 U/min. In one embodiment of the method, the pH value of the feed is from pH 3 to pH 12. In one embodiment of the method, the ratio (S/V) of the electrode surface (S) to the volume of the feed (V) is 0.5 to 0, 7. In one embodiment of the method, the electrode surface (S) is 700 to 900 cm 2 . In one embodiment of the method, the speed is the at least one agitator from 100 to 800 rpm, for example from 200 to 600 rpm, in particular from 400 to 500 rpm.
In einer Ausführungsform des Verfahrens umfassen die im Wasser enthaltenen Verunreinigungen organische Stoffe. In einer weiteren Ausführungsform umfassen die im Wasser enthaltenen Verunreinigungen Phenole. In einer anderen Ausführungsform umfassen die im Wasser enthaltenen Verunreinigungen Schwefel. In einer anderen Ausführungsform umfassen die im Wasser enthaltenen Verunreinigungen Farbstoffpartikel. In einer Ausführungsform des Verfahrens umfassen die im Wasser enthaltenen Verunreinigungen Schwebstoffe. In einer anderen Ausführungsform des Verfahrens umfassen die im Wasser enthaltenen Verunreinigungen emulgiertes Öl. In einer anderen Ausführungsform des Verfahrens umfassen die im Wasser enthaltenen Verunreinigungen (Schwer-)metalle oder Halbmetalle, beispielsweise Kupfer, Zink, Chrom, Cadmium oder Silizium. In one embodiment of the method, the impurities contained in the water include organic substances. In a further embodiment, the contaminants contained in the water include phenols. In another embodiment, the contaminants contained in the water include sulfur. In another embodiment, the contaminants contained in the water include dye particles. In one embodiment of the method, the contaminants contained in the water include suspended solids. In another embodiment of the process, the impurities contained in the water include emulsified oil. In another embodiment of the method, the impurities contained in the water include (heavy) metals or metalloids, for example copper, zinc, chromium, cadmium or silicon.
Die erfindungsgemäße Vorrichtung und das erfindungsgemäße Verfahren eignen sich besonders für den Einsatz in Ölraffinerien und der petrochemischen Industrie, in der Lebensmittelindustrie, der Metallindustrie und der Textilindustrie. The device according to the invention and the method according to the invention are particularly suitable for use in oil refineries and the petrochemical industry, in the food industry, the metal industry and the textile industry.
Bei der Bewertung des Einsatzes von EC ist der Energieverbrauch der entscheidende Betriebskostenfaktor. Aus energetischen Gründen sind sowohl die Effizienz der Elektrolyse und die benötigte Leistung des Rührwerks sehr wichtig. Diese Variablen werden maßgeblich durch die Geometrie des Reaktors beeinflusst. Bei der erfindungsgemäßen Vorrichtung sind die Konfigurationen der Elektroden und des Reaktors so gestaltet, dass sich die elektrochemisch erzeugten Koagulantien sehr gut und sehr schnell mit den Verunreinigungen vermischen, damit sich Flocken bilden können. When evaluating the use of EC, energy consumption is the key operating cost factor. For energy reasons, both the efficiency of the electrolysis and the required power of the agitator are very important. These variables are significantly influenced by the geometry of the reactor. In the device according to the invention, the configurations of the electrodes and the reactor are designed such that the electrochemically produced coagulants mix very well and very quickly with the impurities so that flocs can form.
An der Kathodenelektrode findet eine Elektrolyse statt, die zur Bildung von Gasblasen führt, die bei schlechter Anströmung an der Elektrodenoberfläche anhaften können und einen erheblichen zusätzlichen Widerstand und Span- nungsanstieg verursachen. Durch den runden Querschnitt des zylinderförmigen Zentralraums arbeitet das mindestens eine Rührwerk sehr effektiv und erzielt in den spiralförmigen Kanälen eine gleichmäßige Überströmung der Elektrodenoberflächen, was zu einer Verbesserung der Elektrolyseeffizienz führt. Aufgrund der Form der Elektroden ist die Strömungsgeschwindigkeit an der Oberfläche der Elektroden hoch, und es erfolgt eine gründliche Durchmischung der Flüssigkeit, was zu geringerer Schaumbildung führt. Für Feststoffe, emulgiertes Öl und (Halb-)Metalle, beispielsweise Kupfer, Chrom, Blei, Quecksilber oder Silizium, wird eine Entfernungseffizienz von mehr als 90 Prozent erreicht. Electrolysis takes place at the cathode electrode, which leads to the formation of gas bubbles, which can adhere to the electrode surface if the flow is poor and cause considerable additional resistance and voltage. cause an increase in voltage. Due to the round cross section of the cylindrical central space, the at least one agitator works very effectively and achieves a uniform flow over the electrode surfaces in the spiral channels, which leads to an improvement in the electrolysis efficiency. Due to the shape of the electrodes, the flow velocity on the surface of the electrodes is high and the liquid is thoroughly mixed, which leads to less foam formation. A removal efficiency of more than 90 percent is achieved for solids, emulsified oil and (semi-)metals, such as copper, chromium, lead, mercury or silicon.
Die erfindungsgemäße Lösung bietet im Vergleich zu konventionellen EC- Systemen mit Plattenelektroden zahlreiche Vorteile: einen geringeren Energiebedarf aufgrund der Entfernung der Passivierung durch das Strömungsmuster; einen geringeren Platzbedarf durch Integration dreier Prozesse (Elektrokoagulation, Elektroflotation und Sedimentation) in ein System; eine geringere Behandlungszeit aufgrund der guten Vermischung von Koagulantien und Verunreinigungen; einen geringeren Filtrationsaufwand aufgrund der gebildeten großen Flocken und eine geringere Schaumbildung aufgrund der höheren Geschwindigkeit der Fließoberfläche. Weitere Vorteile und Ausgestaltungen der Erfindung ergeben sich aus der Beschreibung und den beiliegenden Abbildungen. The solution according to the invention offers numerous advantages compared to conventional EC systems with plate electrodes: lower energy requirements due to the removal of passivation by the flow pattern; a smaller space requirement by integrating three processes (electrocoagulation, electroflotation and sedimentation) into one system; a shorter treatment time due to the good mixing of coagulants and impurities; a lower filtration effort due to the large flocs formed and less foam formation due to the higher speed of the flow surface. Further advantages and refinements of the invention result from the description and the accompanying illustrations.
Beispiele Examples
Figur 1 zeigt zwei perspektivische Ansichten einer Ausführungsform der erfindungsgemäßen Vorrichtung 10. Die linke Abbildung zeigt eine Seitenansicht, die rechte Abbildung eine Ansicht von schräg oben. Figure 1 shows two perspective views of an embodiment of the device 10 according to the invention. The left figure shows a side view, the right figure shows a view obliquely from above.
Ein zylinderförmiger Zentralraum 11 der Vorrichtung 10 ist aus einem durchsichtigen Kunststoff hergestellt und ist am oberen Ende offen. Um den zylinderförmigen Zentralraum 11 ist ein zylinderförmiger Außenraum 12 angeordnet, der einen Kragen des zylinderförmigen Zentralraums 11 bildet und ebenfalls aus durchsichtigem Kunststoff gefertigt ist. Der zylinderförmige Zentralraum 1 1 weist nahe seinem unteren Ende eine Flüssigkeitszufuhr 13 auf, der zylinderförmige Außenraum 12 weist nahe seines oberen Randes eine Flüssigkeitsabfuhr 14 auf. Im inneren des zylinderförmigen Zentralraums 11 sind spiralförmig gebogene Elektrodenblätter 15 in Form von zwei kombinierten archimedischen Spiralen so angeordnet, dass zwischen Anode und Kathode spiralförmige Strömungskanäle ausgebildet sind. Die Spiralen 15 sind beabstandet vom Boden 17 des zylinderförmigen Zentralraums 11 angeordnet. A cylindrical central space 11 of the device 10 is made of a transparent plastic and is open at the upper end. A cylindrical outer space 12 is arranged around the cylindrical central space 11, which forms a collar of the cylindrical central space 11 and is also made of transparent plastic. The cylindrical central space 11 has a liquid supply 13 near its lower end, the cylindrical outer space 12 has a liquid discharge 14 near its upper edge. In the interior of the cylindrical central space 11, spirally curved electrode sheets 15 are arranged in the form of two combined Archimedean spirals in such a way that spiral-shaped flow channels are formed between the anode and cathode. The spirals 15 are arranged at a distance from the bottom 17 of the cylindrical central space 11.
Mit der erfindungsgemäßen Vorrichtung und einer Elektrokoagulationsvorrichtung des Standes der Technik mit in einem rechteckigen Gehäuse parallel angeordneten rechteckigen planen Plattenelektroden, unter denen ein Rührwerk angeordnet ist, wurden jeweils mehrere Betriebsversuche unterschiedlicher Dauer durchgeführt und es wurden jeweils der Verlauf der Spannung über die Zeit gemessen und die Schaumbildung beobachtet. With the device according to the invention and an electrocoagulation device of the prior art with rectangular flat plate electrodes arranged in parallel in a rectangular housing, under which an agitator is arranged, several operating tests of different durations were carried out and the course of the voltage over time was measured and the Foam formation observed.
Die Versuchsbedingungen sind in den Tabellen 1 -3 zusammengefasst. Als Feed wurde eine halogenfreie Bearbeitungsemulsion mit einem Ölgehalt von 8 Gew.-% und einem Feststoffgehalt von <5 Gew.-%, pH 9,0 eingesetzt, die 136 mg/l Ammonium, <2 mg/l Cadmium, 2 mg/l Blei, 7 mg/l Kupfer, 13 mg/l Zink, 6 mq/l Chrom, 0,076 Gew.-% Schwefel, 921 mq/l Phosphor, 2.182 mq/l Aluminium und 1 1.800 mq/l Silizium enthielt. Figur 2 zeigt den Spannungsverlauf über die Zeit in der erfindungsgemäßen Vorrichtung (durchgezogen) und dem Elektrokoagulationsreaktor des Standes der Technik (gestrichelt). Für die drei durchgeführten Versuche wurden die jeweiligen Betriebszeiten entsprechend der Verunreinigungskonzentration im Feed gewählt. Höhere Konzentrationen erfordern eine längere Betriebszeit. Die unterschiedlichen Ausgangsspan- nungen sind ebenfalls auf die Konzentrationsunterschiede zurückzuführen. The test conditions are summarized in Tables 1 -3. A halogen-free processing emulsion with an oil content of 8% by weight and a solids content of <5% by weight, pH 9.0, containing 136 mg/l ammonium, <2 mg/l cadmium, 2 mg/l was used as feed Lead, 7 mg/l copper, 13 mg/l zinc, 6 mq/l chromium, 0.076 wt.% sulfur, 921 mq/l phosphorus, 2,182 mq/l aluminum and 1,800 mq/l silicon. Figure 2 shows the voltage curve over time in the device according to the invention (solid line) and the prior art electrocoagulation reactor (dashed line). For the three experiments carried out, the respective operating times were selected according to the impurity concentration in the feed. Higher concentrations require longer operating time. The different output voltages are also due to the concentration differences.
Tabelle 1
Figure imgf000014_0001
Table 1
Figure imgf000014_0001
Tabelle 2
Figure imgf000014_0002
Table 2
Figure imgf000014_0002
Tabelle 3
Figure imgf000014_0003
Die beiden Elektrokoagulationsvorrichtungen, deren Elektroden jeweils aus Aluminiumblechen mit einer Fläche von 836 cm2 bestanden, wurden in allen Versuchen jeweils mit 1300 ml Flüssigkeit befüllt und es wurde für die jeweilige Zeitdauer ein Strom von 5 A durch die Vorrichtung geleitet. Die Feedkonzentration wurde durch Mischung entsprechender Volumina Wasser mit dem Feed eingestellt. Das Rührwerk wurde jeweils mit einer Rührerdrehzahl von 400 U/min betrieben, um die Flüssigkeit kontinuierlich in der Vorrichtung zirkulieren zu lassen. Die Leitfähigkeit der Flüssigkeit, ihr pH-Wert, die Flüssigkeitstemperatur und die anliegende Spannung wurden jeweils zu Beginn des Versuchs (Start) und nach Beendigung des Versuchs (Ende) gemessen. Table 3
Figure imgf000014_0003
The two electrocoagulation devices, whose electrodes each consisted of aluminum sheets with an area of 836 cm 2 , were each filled with 1300 ml of liquid in all experiments and a current of 5 A was passed through the device for the respective period of time. The feed concentration was adjusted by mixing appropriate volumes of water with the feed. The agitator was operated at a stirrer speed of 400 rpm in order to allow the liquid to circulate continuously in the device. The conductivity of the liquid, its pH value, the liquid temperature and the applied voltage were measured at the beginning of the experiment (Start) and after the end of the experiment (End).
Wie aus Figur 2 ersichtlich, zeigt die erfindungsgemäße Vorrichtung einen deutlich geringeren Spannungsbedarf und somit einen reduzierten Energiebedarf bei gleicher Stromstärke als die Vorrichtung des Standes der Technik. As can be seen from Figure 2, the device according to the invention has a significantly lower voltage requirement and thus a reduced energy requirement for the same current strength than the device of the prior art.
Figur 3 zeigt die Schaumentwicklung in der erfindungsgemäßen Vorrichtung (linke Reihe) und dem Elektrokoagulationsreaktor des Standes der Technik (rechte Reihe) im Vergleich nach 5, 10, 15 und 20 Minuten Betriebsdauer. Wie auf den Bildern der Figur 3 zu sehen ist, wurde in der Vorrichtung des Standes der Technik auf der Flüssigkeitsoberfläche ein großes Volumen an Schaum erzeugt. Das deutet darauf hin, dass die Plattenelektroden als Barriere für eine gute Vermischung von Al-Ionen und OH-Ionen für die Produktion von Koagulantien sowie für die Vermischung der produzierten Koagulantien mit den Verunreinigungen wirken, was zu einer geringeren Abscheideeffizienz und somit Schaumbildung beim Rühren führt. Bei der erfindungsgemäßen Vorrichtung jedoch ist die Geschwindigkeit an der Oberfläche aufgrund der spiralförmigen Konfiguration hoch, was zu einer guten Durchmischung und vernachlässigbarer Schaumbildung und somit auch höherer Effizienz führt. Figure 3 shows the foam development in the device according to the invention (left row) and the electrocoagulation reactor of the prior art (right row) in comparison after 5, 10, 15 and 20 minutes of operation. As can be seen in the images of Figure 3, in the prior art device a large volume of foam was generated on the liquid surface. This indicates that the plate electrodes act as a barrier for good mixing of Al ions and OH ions for the production of coagulants as well as for the mixing of the produced coagulants with the impurities, which leads to lower separation efficiency and thus foam formation during stirring . In the device according to the invention, however, the speed on the surface is high due to the spiral configuration, which leads to good mixing and negligible foam formation and thus higher efficiency.
Es wurden Versuche durchgeführt, um den Effekt des Rührens auf die Elektrokoagulation in einer erfindungsgemäßen Vorrichtung zu ermitteln. Die erfindungsgemäße Elektrokoagulationsvorrichtung, deren Elektroden jeweils aus Aluminiumblechen mit einer Fläche von 836 cm2 bestanden, wurde in allen Ver- suchen jeweils mit 1300 ml Flüssigkeit befüllt und es wurde für 10 min ein Strom von 5 A durch die Vorrichtung geleitet. Die Leitfähigkeit der Flüssigkeit, ihr pH-Wert, die Flüssigkeitstemperatur und die anliegende Spannung wurden jeweils zu Beginn des Versuchs (Start) und nach Beendigung des Versuchs (Ende) gemessen. Die Ergebnisse sind in Tabelle 4 zusammengefasst. Experiments were carried out to determine the effect of stirring on electrocoagulation in a device according to the invention. The electrocoagulation device according to the invention, whose electrodes each consisted of aluminum sheets with an area of 836 cm 2 , was used in all applications. each was filled with 1300 ml of liquid and a current of 5 A was passed through the device for 10 minutes. The conductivity of the liquid, its pH value, the liquid temperature and the applied voltage were measured at the beginning of the experiment (Start) and after the end of the experiment (End). The results are summarized in Table 4.
Tabelle 4
Figure imgf000016_0001
Table 4
Figure imgf000016_0001
Figur 4 zeigt den Spannungsverlauf über die Zeit in der erfindungsgemäßen Vorrichtung bei den verschiedenen Rührgeschwindigkeiten. Figure 4 shows the voltage curve over time in the device according to the invention at the different stirring speeds.
Die Ergebnisse der Versuche zeigen, dass Rühren bei der Elektrokoagulation (EC) einen wichtigen Einfluss auf die Entfernung von Verunreinigungen und den Energieverbrauch hat. Aus den Versuchen ergibt sich, dass die Spannungszunahme während der EC ohne Rühren etwa dreimal größer ist als mit Rühren. Die Effizienz der Entfernung der Verunreinigungen (gemessen anhand der Trübung der Flüssigkeit) bei EC mit Rührgeschwindigkeiten von 400 bis 500 U/min beträgt 82-90%, während ohne Rühren nur 56% erreicht werden. The results of the experiments show that stirring during electrocoagulation (EC) has an important influence on the removal of impurities and energy consumption. The experiments show that the increase in voltage during EC without stirring is approximately three times greater than with stirring. The impurity removal efficiency (measured by the turbidity of the liquid) at EC with stirring speeds of 400 to 500 rpm is 82-90%, while only 56% is achieved without stirring.
Die im Betrieb mit Rühren gebildeten Flocken sind sehr groß und können leicht abgetrennt werden. Ohne Rühren sind die gebildeten Flocken sehr klein und müssen mit hohem Filtrationsaufwand abgetrennt werden. Figur 5 zeigt einen Vergleich der Sedimentation der durch EC gebildeten Flocken 15 min nach Ende der EC-Behandlung, links (a) durch EC mit Rühren behandelte Flüssigkeit und rechts (b) durch EC ohne Rühren behandelte Flüssigkeit. Ficjur 6 zeigt eine Aufsicht einer weiteren Ausführungsform einer erfindungsgemäßen Vorrichtung 20; Figur 7 zeigt eine Seitenansicht der Vorrichtung 20. The flakes formed during stirring operation are very large and can be easily separated. Without stirring, the flakes formed are very small and require a lot of filtration to be separated. Figure 5 shows a comparison of the sedimentation of the flocs formed by EC 15 min after the end of the EC treatment, on the left (a) liquid treated by EC with stirring and on the right (b) liquid treated by EC without stirring. Figure 6 shows a top view of a further embodiment of a device 20 according to the invention; Figure 7 shows a side view of the device 20.
Der Batch-Reaktor 20 ist auf einem Gestell 29 montiert und 20 verfügt über einen Zulauf 21 mit einem Einlassventil 22 für die Zufuhr von zu behandelnder Flüssigkeit in den Batch-Reaktor 20. Ein Rührwerk 24 ist an einem Rührerhalter 23 befestigt und wird über einen Elektromotor 25 angetrieben. Im Inneren des Batch- Reaktors 20 befinden sich spiralförmig ausgestaltete Aluminiumelektroden 26. An der tiefsten Stelle des Batch-Reaktors 20 ist ein Ablauf 28 mit einem Auslassventil 27 angeordnet, über den sich der Batch-Reaktor 20 entleeren lässt. zeigt eine Aufsicht einer anderen Ausführungsform der erfindungsgemäßen Vorrichtung 30. Im Inneren eines zylindrischen Behälters sind eine Kathode 31 und eine Anode 32 aus spiralförmig aufgerollten Blechen so angeordnet, dass sie sich nicht berühren. Im Zentrum der Elektroden 31 , 32 verläuft dieThe batch reactor 20 is mounted on a frame 29 and 20 has an inlet 21 with an inlet valve 22 for supplying liquid to be treated into the batch reactor 20. An agitator 24 is attached to a stirrer holder 23 and is driven by an electric motor 25 powered. Inside the batch reactor 20 there are spiral-shaped aluminum electrodes 26. At the lowest point of the batch reactor 20 there is a drain 28 with an outlet valve 27, via which the batch reactor 20 can be emptied. shows a top view of another embodiment of the device 30 according to the invention. Inside a cylindrical container, a cathode 31 and an anode 32 made of spirally rolled sheets are arranged so that they do not touch each other. The runs in the center of the electrodes 31, 32
Achse eines Rührwerks 33, dessen Flügel unterhalb der Elektroden 31 , 32 angeordnet sind. Axis of an agitator 33, the blades of which are arranged below the electrodes 31, 32.
Figur 9 zeigt eine Aufsicht einer Ausführungsform der erfindungsgemäßen Vorrichtung 40 mit mehreren Elektroden 41 , 42. Im Inneren eines zylindrischen Behälters sind mehrere Kathoden 41 und Anoden 42 jeweils abwechselnd so angeordnet, dass sie sich nicht berühren. Die einzelnen Bleche der Kathoden 41 und Anoden 42 sind jeweils so gebogen, dass alle Elektroden 41 , 42 gemeinsam einen Wirbel bilden. Entlang der Mittelachse der Vorrichtung 40 verläuft die Achse eines Rührwerks 43, dessen Flügel unterhalb der Elektroden 41 , 42 angeordnet sind. Bezugszeichenliste 9 shows a top view of an embodiment of the device 40 according to the invention with several electrodes 41, 42. Inside a cylindrical container, several cathodes 41 and anodes 42 are arranged alternately so that they do not touch each other. The individual sheets of the cathodes 41 and anodes 42 are each bent in such a way that all electrodes 41, 42 together form a vortex. The axis of an agitator 43 runs along the central axis of the device 40, the blades of which are arranged below the electrodes 41, 42. Reference symbol list
10 Elektrokoagulationsvorrichtung 10 electrocoagulation device
11 zylindrischer Reaktorraum 11 cylindrical reactor room
12 zylindrischer Außenraum / Überlauf12 cylindrical outer space / overflow
13 Flüssigkeitszufuhr 13 Hydration
14 Flüssigkeitsabfuhr 14 fluid drainage
15 Spiralelektroden 15 spiral electrodes
16 Rührwerk 16 agitator
17 Boden 17 floor
20 Batch-Reaktor 20 batch reactor
21 Zulauf 21 inflow
22 Einlassventil 22 inlet valve
23 Rührerhalter 23 stirrer holders
24 Rührwerk 24 agitator
25 Elektromotor 25 electric motor
26 Aluminiumelektrode 26 aluminum electrode
27 Auslassventil 27 exhaust valve
28 Ablauf 28 Process
29 Gestell 29 frame
30 Elektrokoagulationsvorrichtung30 electrocoagulation device
31 Kathode 31 cathode
32 Anode 32 anode
33 Rührwerk 33 agitator
40 Elektrokoagulationsvorrichtung40 electrocoagulation device
41 Kathode 41 cathode
42 Anode 42 anode
43 Rührwerk 43 agitator

Claims

Patentansprüche Patent claims
1. Vorrichtung (10) zur Elektrokoagulation, welche spiralförmig gewickelte Elektrodenblätter (15) für Kathode und Anode umfasst, die beabstandet voneinander in einem zylinderförmigen Zentralraum (11 ) angeordnet sind, wobei die Längsachse des Zentralraums (11 ) die Mittelachse der Spiralen (15) bildet, dadurch gekennzeichnet, dass der zylinderförmige Zentralraum nach unten durch einen Boden (17) begrenzt ist, der von den Spiralen (15) beabstandet ist, 1. Device (10) for electrocoagulation, which comprises spirally wound electrode sheets (15) for cathode and anode, which are arranged at a distance from one another in a cylindrical central space (11), the longitudinal axis of the central space (11) being the central axis of the spirals (15). forms, characterized in that the cylindrical central space is bounded at the bottom by a base (17) which is spaced from the spirals (15),
2. Vorrichtung nach Anspruch 1 , worin in dem zylinderförmigen Zentralraum (11 ) mindestens ein Rührwerk (16) angeordnet ist. 2. Device according to claim 1, wherein at least one agitator (16) is arranged in the cylindrical central space (11).
3. Vorrichtung (10) nach Anspruch 2, worin mindestens ein Rührwerk (16) unterhalb der Elektroden (15) angeordnet ist. 3. Device (10) according to claim 2, wherein at least one agitator (16) is arranged below the electrodes (15).
4. Vorrichtung (10) nach Anspruch 2 oder 3, worin mindestens ein Rührwerk (16) oberhalb der Elektroden (15) angeordnet ist. 4. Device (10) according to claim 2 or 3, wherein at least one agitator (16) is arranged above the electrodes (15).
5. Vorrichtung (10) nach einem der Ansprüche 2 bis 4, worin im Kern der Spiralen (15) ein zylindrischer Bereich freigehalten ist, in dem mindestens ein Rührwerk (16) angeordnet ist. 5. Device (10) according to one of claims 2 to 4, wherein a cylindrical area is kept free in the core of the spirals (15), in which at least one agitator (16) is arranged.
6. Vorrichtung (10) nach einem der Ansprüche 1 bis 4, worin der zylinderförmige Zentralraum (11 ) mindestens einen nahe des unteren Endes des Zylinders angeordneten Flüssigkeitseinlass (13) aufweist. 6. Device (10) according to one of claims 1 to 4, wherein the cylindrical central space (11) has at least one liquid inlet (13) arranged near the lower end of the cylinder.
7. Vorrichtung (10) nach einem der Ansprüche 1 bis 6, welche einen koaxial zum zylinderförmigen Zentralraum (11 ) angeordneten zylinderförmigen Außen- raum (12) aufweist, der einen größeren Durchmesser aufweist als der zylinderförmige Zentralraum (11 ) und der dafür eingerichtet ist, am Kopf des zylinderförmigen Zentralraums (11 ) austretende Flüssigkeit aufzunehmen. 7. Device (10) according to one of claims 1 to 6, which has a cylindrical outer space arranged coaxially to the cylindrical central space (11). space (12) which has a larger diameter than the cylindrical central space (11) and which is designed to receive liquid emerging from the head of the cylindrical central space (11).
8. Vorrichtung nach einem der Ansprüche 1 bis 7, worin die Anode metallisches Eisen, Aluminium, oder Titan enthält. 8. Device according to one of claims 1 to 7, wherein the anode contains metallic iron, aluminum, or titanium.
9. Verfahren zur Behandlung von Verunreinigungen enthaltendem Wasser durch Elektrokoagulation, bei dem das Verunreinigungen enthaltende Wasser in eine Vorrichtung (10) nach einem der voranstehenden Ansprüche gefüllt wird, das Verunreinigungen enthaltende Wasser in der Vorrichtung (10) kontinuierlich radial durch die zwischen den spiralförmig gewickelten Elektrodenblättern (15) ausgebildeten spiralförmigen Kanäle geführt wird, Gleichspannung an die Elektroden (15) angelegt wird, wodurch elektrochemisch Metallhydroxide er- zeugt werden, die eine Ausflockung der Verunreinigungen bewirken, und die ausgeflockten Verunreinigungen anschließend abgetrennt werden. 9. A method for treating water containing impurities by electrocoagulation, in which the water containing impurities is filled into a device (10) according to one of the preceding claims, the water containing impurities in the device (10) continuously radially through the spirally wound between the Electrode sheets (15) formed spiral channels, DC voltage is applied to the electrodes (15), whereby metal hydroxides are electrochemically generated, which cause flocculation of the impurities, and the flocculated impurities are then separated.
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