JP2008043891A - Closed cylindrical electrolyzer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a closed cylindrical electrolyzer which reduces power consumption by inhibiting reverse reaction, has an easily disassembled structure to improve maintainability, and can be suitably used to decompose ammonia nitrogen or nitrate nitrogen. <P>SOLUTION: In the closed cylindrical electrolyzer 1, an inner cylinder 6 is concentrically installed in an outer cylinder 2 having flanges 5 on both ends, and having a liquid inlet 3 and a liquid outlet 4 on both respective ends, a cylindrical anode and a cylindrical cathode are alternatively, concentrically arranged so as to leave a narrow space between them, a space between the inner cylinder and the innermost electrode, and a space between the outer cylinder and the outermost electrode are made narrow, and flanged power supply plates 12, 14, 16 formed on both electrode ends and the flanges on both ends of the outer cylinder are combined by inserting bolts into through holes 20 and fastening them with nuts. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

The present invention relates to a cylindrical electrolyzer with low power consumption and excellent maintainability.
More specifically, the decomposition of ammonia-type nitrogen or nitrate-type nitrogen that reduces power consumption by suppressing the progress of the reverse reaction and has a structure that can be easily decomposed to improve maintainability. The present invention relates to a hermetic cylindrical electrolyzer that can be suitably used.

Wastewater containing ammonia nitrogen components is difficult to treat by the coagulation sedimentation method and other chemical additions, and the biological treatment with anaerobic bacteria is carried out exclusively.
Since the biological treatment method is performed by two steps, a nitrification step for converting ammonia nitrogen to nitrate nitrogen and a denitrification step for converting nitrate nitrogen to nitrogen gas, two different reaction tanks are required. However, since a very long processing time is required, there is a problem that the processing efficiency is extremely poor.

In addition, in this biological treatment method, a large-capacity anaerobic tank is required in order to retain denitrifying bacteria, and there is a problem that the equipment construction cost increases and the installation area of the apparatus increases.
Furthermore, the activity of the denitrifying bacteria is significantly affected by the ambient temperature environment, components contained in the water to be treated, and the like.
Therefore, especially in the winter when the temperature is low, the activity is reduced, and as a result, the denitrification action is lowered and the treatment efficiency becomes unstable.

In addition to this, in recent years, the development of effective and simple treatment methods has increased along with stricter wastewater treatment standards such as the total amount of nitrogen in wastewater being regulated in recent years. Therefore, there is a need for a treatment method that can meet the needs of small-scale wastewater treatment.
In recent years, a method for treating nitrate nitrogen-containing wastewater using electrolysis has been proposed as a method for dealing with this (Patent Documents 1 to 4 and Non-Patent Document 1).
The method reduces nitrate ions (NO ₃ ⁻ ) at the cathode of the electrolytic cell to produce nitrite ions (NO ₂ ⁻ ), then further reduces the NO ₂ ⁻ to produce ammonia, and at the other anode Is to denitrify waste water by producing chlorine or active oxygen and reacting the produced ammonia with chlorine or active oxygen to turn ammonia into nitrogen.

[Prior art documents]
Japanese Patent No. 3524894 Japanese Patent No. 3530511 JP2003-88871 JP 2003-230883 A Electrochemistry, 70, No. 2 (2002), N HIRO, T KOIZUMI, T RAKUMA, D TAKAOKA, K TAKIZAWA “Latest Emulsion Application Technology” Chemical Advanced Technology Series 3, pages 9-21, Chunichisha Co., Ltd. June 25, 1991

In the proposed method of treating wastewater containing nitrate nitrogen using electrolysis, in addition to the production of chlorine or active oxygen on the anode side, the nitrite ions produced on the cathode side diffuse to the anode side, where A reverse reaction that oxidizes to generate nitrate ions also occurs as a side effect, causing a problem of reducing nitrogen removal efficiency.
Furthermore, on the cathode side, chlorine generated at the anode diffuses to the cathode side, and a reverse reaction that is reduced there to generate chlorine ions also occurs as a side effect, resulting in a problem of reducing nitrogen removal efficiency. Yes.

As described above, in this method for treating nitrate-nitrogen-containing wastewater, electric energy is also consumed in side reactions and is inefficient.
A technique for solving this problem has already been proposed in Patent Document 2, which uses an electrolytic cell partitioned into a cathode chamber and an anode chamber with an ion exchange membrane as a diaphragm, and drains containing nitrate nitrogen. After supplying ammonia to the cathode chamber and performing electrolysis to produce ammonia, the wastewater in which the ammonia is dissolved is moved to the anode chamber, and nitrogen is produced by reacting ammonia with hypochlorous acid or oxygen produced in the anode chamber. This is a method of denitrification.

By the way, in the denitrification method by electrolysis using the ion exchange membrane proposed in Patent Document 2, electrolysis and nitrogen production reaction from ammonia are alternately performed, and the treatment of the nitrate nitrogen-containing waste water is performed. Are intermittent and discontinuous.
In this method, the diaphragm is present as described above, and a pump for transferring the processing liquid from the cathode chamber to the anode chamber is installed between the cathode chamber and the anode chamber.
As described above, in the case where denitrification is performed by electrolysis using a diaphragm, it is inevitable that the structure of the apparatus and the processing operation become complicated, which is not satisfactory.

Therefore, the present inventors have advantages of the simple structure and simple operation of the method for denitrifying wastewater containing nitrate nitrogen by using electrolysis with a diaphragm without taking advantage of the above-described wastewater treatment by electrolysis. An efficient method for treating nitrate-nitrogen-containing wastewater that can reduce waste of electric energy as much as possible has been developed and patent applications have already been filed (Japanese Patent Application Nos. 2005-247964 and 2005-300531).
In this method, the cathode uses aluminum in the former patent application and iron in the latter patent application.

As described above, in this method, aluminum or iron is used for the cathode, which dissolves and emits electrons, and at the same time, reduces the nitrate nitrogen component, thereby generating a reverse ion reaction. Alternatively, the amount of electricity wasted due to the reverse reaction that generates chlorine ions can be apparently compensated, and the waste of electric energy is reduced.
At that time, it is considered to further reduce the cost by using scrap.

The denitrification treatment by electrolysis of nitrate nitrogen-containing wastewater as described above relates to a technique for denitrifying nitrate nitrogen-containing wastewater, although ammonia formed in the middle is decomposed by electrolysis.
Under such circumstances, the present inventor recently found out that there is wastewater containing ammonia at a high concentration, and tried to reduce ammonia by electrolysis of this wastewater.
That is, fresh latex collected from a rubber tree is added with ammonia as an anticoagulant in the plantation to avoid alteration (called plantation latex).

The farm latex is then concentrated at a local factory to produce a concentrated latex, which is then transported to an overseas product manufacturing factory close to the place of consumption and then commercialized.
Therefore, it is calculated | required that it does not change in a conveyance process, The preservative is used for the stable preservation | save, and ammonia is also used for the preservative (nonpatent literature 2).
Therefore, in the product manufacturing process and the concentrated latex manufacturing process, the coagulation inhibitor and the preservative are separated from the latex component, respectively, and the waste water containing ammonia and the COD component is discharged.

The inventor has developed a treatment technique for removing ammonia and COD components from the ammonia and COD component-containing wastewater, and has already filed a patent application (Japanese Patent Application No. 2006-131552).
In the treatment technique, ammonia is decomposed by electrolysis, and at the time of decomposition, sodium chloride is added to the electrolytic solution and reacted with the generated hypochlorite to be oxidized to nitrogen.
In this case, as in the case of nitrate nitrogen, the chlorine produced at the anode diffuses toward the cathode, and the reverse reaction occurs where it is reduced to produce chlorine ions.
Furthermore, ammonia moves to the cathode side by an electric attractive force, and therefore, reaction with hypochlorite formed at the anode is suppressed.

As described above, in the method of treating nitrate nitrogen-containing wastewater utilizing electrolysis, the occurrence of a reverse reaction due to diffusion of nitrite ions generated on the cathode side to the anode side, and the cathode of chlorine generated on the anode Electric energy is wasted due to the generation of chlorine ions, which is a reverse reaction caused by diffusion to the side, and is not used effectively.
The patent filed by the present invention for solving this problem apparently contributes to the effective use of electric energy, but does not provide an essential solution.

In addition, in the method of treating ammonia-containing wastewater using electrolysis, as described above, electrical energy is wasted due to the generation of chlorine ions, which is a reverse reaction caused by the diffusion of chlorine produced at the anode to the cathode side. It has not been.
Furthermore, ammonia moves to the cathode side due to the electric attractive force, and the opportunity to cause a reaction with hypochlorite generated at the anode is reduced. This is also a disadvantage in terms of effective use of electric energy. It has become.

Accordingly, the present inventor has sought to intensively research and develop in order to fundamentally solve the above problems, and as a result, has succeeded in the development.
That is, the present invention is based on the occurrence of a reverse reaction due to diffusion of nitrite ions to the anode side and diffusion of chlorine produced at the anode to the cathode side in the above-described method for treating nitrate nitrogen-containing wastewater using electrolysis. Inhibiting the occurrence of the reverse reaction that occurs, the reverse reaction that occurs due to the diffusion of chlorine produced at the anode to the cathode side, and the movement of ammonia to the cathode side in the method of treating ammonia-containing wastewater using electrolysis As a result, the present invention has succeeded in the research and development of an electrolyzer that can be developed, and as a result, has been successfully developed.

In that case, the present invention was successful in the research and development of an electrolysis apparatus capable of solving these problems fundamentally and structurally. As a result, the present invention was successfully developed. Since it was aimed to be used for wastewater treatment, it was also important to have a structure with excellent maintainability.
Therefore, the present invention is a problem to be solved to provide an electrolysis apparatus that can fundamentally and structurally solve the above problems, that is, an object of the present invention, and is an electrolysis having a structure excellent in maintainability. The object is to provide an apparatus.

  The present invention provides a sealed cylindrical electrolyzer for achieving the above object, which includes flanges at both ends, an outer cylinder having a liquid inlet at one end and a liquid outlet at the other end, Inner cylinders arranged concentrically in the cylinder, cylindrical anodes and cylindrical cathodes arranged concentrically alternately with a narrow gap, a flange-shaped power supply plate formed at one end of the anode, A flange-shaped power feeding plate formed at the end of the cylindrical cathode opposite to the end, and a gap between the inner cylinder and the innermost electrode and a gap between the outer cylinder and the outermost electrode, and The anode flange-shaped power supply plate and the cathode flange-shaped power supply plate are combined with corresponding flanges at both ends of the outer cylinder and assembled.

And the sealed cylindrical electrolyzer forms through-holes at the same positions of the flange-shaped power supply plate of the cylindrical anode and the flange-shaped power supply plate of the cylindrical cathode and the corresponding flanges at both ends of the outer cylinder. It is preferable that the flange-shaped power supply plate of the cylindrical anode and the flange-shaped power supply plate of the cylindrical cathode and the corresponding flanges at both ends of the outer tube are coupled with each other through bolts and nuts.
Further, it is preferable that the liquid inlet and the liquid outlet are coupled in the tangential direction of the outer cylinder. Further, it is preferable to dispose an insulating net between the cylindrical anode and the cylindrical cathode.

In the sealed cylindrical electrolysis apparatus of the present invention, the inner cylinder is arranged in the outer cylinder, thereby reducing the cross section through which the liquid to be treated passes compared to the case where the inner cylinder is not present, and the distance between the electrodes. Therefore, the electrolytic treatment liquid can pass between the electrodes at high speed.
As a result, in the case of treatment of nitrate nitrogen-containing wastewater, diffusion of nitrite ions produced on the cathode side to the anode side and diffusion of chlorine produced on the anode to the cathode side can be suppressed.
Furthermore, in the case of treatment of ammonia-containing wastewater using electrolysis, diffusion of chlorine produced at the anode to the cathode side and movement of ammonium ions to the cathode side can also be suppressed.

  Therefore, as in the case of electrolytic treatment of nitrate nitrogen-containing wastewater using a conventional electrolyzer, the occurrence of a reverse reaction due to diffusion of nitrite ions to the anode side, the chlorine produced at the anode to the cathode side Generation of reverse reaction due to diffusion, occurrence of reverse reaction due to diffusion of chlorine produced at the anode to the cathode side, and reduction of ammonia decomposition due to movement of ammonium ions to the cathode side, as in the case of electrolytic treatment of ammonia-containing wastewater Can be suppressed.

And the sealed cylindrical electrolyzer of the present invention does not have a diaphragm, and therefore, when using this to electrolyze waste water containing nitrate nitrogen, in the case of electrolytic treatment using the diaphragm described above, In comparison, the apparatus structure is simple and the processing operation is simple.
Furthermore, in the present invention, when the nitrate nitrogen component is reduced as the aluminum is dissolved, the amount of electricity wasted due to the reverse reaction that generates nitrate ions or the reverse reaction that generates chlorine ions is apparently compensated. In comparison, the current efficiency can be essentially improved.
In addition, since the sealed tubular electrolysis apparatus of the present invention has the structure as described above, it is easy to assemble and disassemble and is suitable for use in wastewater treatment.

Hereinafter, embodiments including the best mode for carrying out the invention will be described in detail with reference to FIGS. 1 to 3, but the present invention is not limited to these embodiments. Needless to say, it is specified by the scope of claims.
FIG. 1 shows an overall view of a preferred sealed tubular electrolysis apparatus of the present invention, and FIG. 2 shows a preferred tubular anode (anode) and tubular cathode (cathode) used in the apparatus.
FIG. 3 illustrates all components such as an inner cylinder, an outer cylinder, an insulating net, a cylindrical anode, and a cylindrical cathode used when assembling the sealed cylindrical electrolyzer of the present invention.

The illustrated sealed tubular electrolysis apparatus 1 has a cylindrical inner cylinder 6 concentrically disposed at the center of a cylindrical outer cylinder 2, and a cylindrical outer cathode 13 from the outside between the two cylinders. A cylindrical anode 11 and a cylindrical inner cathode 15 are disposed concentrically in order in the outer cylinder 2.
Further, an outer insulating net 18 and an inner insulating net 19 are arranged between the outer cathode 13 and the anode 11 and between the inner cathode 15 and the anode 11, respectively, and the anode and the cathode are short-circuited by these. It has a structure to prevent.

The outer tube 2 is provided with flanges 5 at both ends. The outer cathode 13 and the inner cathode 15 are respectively provided with flange-like outer power supply plates 14 and flange-like inner power supply plates 16 at the upper ends thereof. A flange-shaped power supply plate 12 is attached to the lower end.
A through hole 20 is formed at the same position in the flange 5 at the upper end of the outer cylinder 2, the flange-shaped outer power supply plate 14 for the outer cathode, and the flange-shaped inner power supply plate 16 for the inner cathode. The through-hole 20 is formed in the same position also in the flange 5 of a part and the flange-shaped electric power feeding plate 12 of an anode.

In the illustrated sealed cylindrical electrolysis apparatus 1, the inner cylinder, the insulating net, the cylindrical anode, the cylindrical cathode, and the like are fixed to the outer cylinder by passing bolts through the through holes 20 and tightening them with nuts. It will be.
The fixing is performed by a combination of a bolt and a nut in the illustrated sealed tubular electrolysis apparatus 1, and this is preferable in the electrolysis apparatus of the present invention.

Although it is as described above, the fixing means is not particularly limited to those described above, and various types can be used as long as the inner cylinder can be detachably attached to the outer cylinder. Can do.
For example, a clamp, screwing, or a center bolt can be exemplified.
Since it is as above-mentioned, in the sealed cylindrical electrolysis apparatus 1, each part can be attached or detached easily, As a result, a maintenance can be performed easily.

In the fixing, in order to fix these components stably, the packing 7, the end plate 8, the O-ring 9, the pressing plate 10, the joining ring 17 and the like are used in addition to the above.
Specifically, between the flange 5 and the flange-shaped outer power feeding plate 14, between the flange-shaped outer power feeding plate 14 and the flange-shaped inner power feeding plate 16, and between the flange 5 and the anode flange-shaped power feeding plate 12. Each has a packing 7 inserted therein.
Further, end plates 8 are attached to the outside of the flange-shaped inner power supply plate 16 and the anode flange-shaped power supply plate 12, and the packing 7 is inserted between the power supply plate and the end plate 8. .

Further, a pressing plate 10 is attached to the outside of the end plate 8 so that the inner cylinder 6 is stably fixed to the outer cylinder 2. Specifically, the inner cylinder 6 and the pressing plate 10 are disposed between the inner cylinder 6 and the pressing plate 10. The O-ring 9 is inserted, whereby the inner cylinder 6 is stably fixed in the outer cylinder.
A screw penetration hole is formed in the pressing plate 10, and the screw is passed through the hole and then screwed into the hole formed in the end plate 8, thereby fixing the pressing plate 10 to the end plate 8. Then, the inner cylinder is stably fixed to the outer cylinder.
At that time, the O-ring 9 is inserted between the inner cylinder and the end plate 8, and thereby the inner cylinder is stably fixed.

In the illustrated sealed tubular electrolysis apparatus 1, the inlet 3 and outlet 4 of the liquid to be processed are attached to the outside of the outer cylinder 2 in the tangential direction of the outer cylinder. After flowing into the cylinder 2, it is high-speed between the anode and cathode disposed between the outer cylinder 2 and the inner cylinder 6, between the inner cylinder and the inner cathode, and between the outer cylinder and the outer cathode. And flows out of the sealed tubular electrolysis apparatus 1 from the outlet 4.
In addition, a power cable terminal mounting hole 21 is formed in the flange-shaped power supply plate, and electricity is supplied to both electrodes by mounting the power cable here, and the liquid to be treated rises between the anode and cathode electrodes. It will be electrolyzed.

For example, when an ammonia-containing wastewater to which salt is added is subjected to electrolytic treatment, the hypochlorite produced at the anode reacts with the ammonia contained in the wastewater to oxidize the ammonia to nitrogen.
In that case, since the liquid to be treated moves at high speed in the electrolytic cell, it is possible to suppress the diffusion of chlorine generated at the anode to the cathode side, and the movement of the ammonium ions contained to the cathode side. Generation | occurrence | production of the reverse reaction by the said diffusion and reduction of ammonia decomposition | disassembly by the movement of the said ammonium ion can be suppressed.

In the present invention, the outer cylinder is preferably a cylinder, but the shape is not particularly limited as long as it is a cylinder, and the cross-sectional shape may be an ellipse or a polygon. In the case of a polygon, it is a pentagon or more. Is good.
The inner cylinder, the insulating net, the cylindrical anode, and the cylindrical cathode arranged in the outer cylinder should be cylindrical like the outer cylinder, and should be concentrically arranged in the outer cylinder. .
If the cross section of the outer cylinder is other than a circle, the inner cylinder, the insulating net, the cylindrical anode and the cylindrical cathode should have a cross section similar to that of the outer cylinder. It must be arranged concentrically.

In the present invention, it is necessary for the liquid to be processed to pass between the cylindrical anode and the cylindrical cathode at a high speed. Therefore, in order to reduce the cross-sectional area of the liquid to be processed, the inner cylinder is placed in the outer cylinder. Therefore, the diameter of the cross section of the inner cylinder is preferably about 4/5 to 1/5 of the diameter of the cross section of the outer cylinder, and is preferably increased as the diameter of the cross section of the outer cylinder is increased.
Specifically, the outer cylinder has a cross-sectional diameter of 0.1 to 1 m, the inner cylinder has a cross-sectional diameter of 0.05 to 0.8 m, and the outer cylinder has a cross-sectional diameter of 0.2 to 0.00 m. The diameter of the cross section of the inner cylinder is preferably 0.1 to 0.2 m.

The material of the outer cylinder and the inner cylinder is not particularly limited, but a commercially available metal pipe or plastic pipe can be used as long as the cross-sectional diameter is within the above range. In the case of a metal pipe, a valve such as titanium is used. Examples of the metal or stainless steel whose inner wall is lined with a synthetic resin can be given. In the case of a plastic pipe, a vinyl chloride resin, an acrylic resin, or the like can be given.
Among these pipes, it is not necessary to consider the prevention of a short circuit with an electrode, so that a plastic pipe is preferable, and a vinyl chloride pipe is particularly preferable because it is inexpensive.

In the case of the plastic pipe, although it is expensive, a special effect can be obtained by using a transparent pipe.
That is, in that case, by arranging a lighting fixture in the inner cylinder, since both pipes are transparent, the inner and outer cylinders can be illuminated by the illumination in the inner cylinder, and the electrolytic state can be observed. There is an advantage.
Further, the interval between the cylindrical anode and the cylindrical cathode is preferably as narrow as possible so long as the electrodes are not short-circuited and the liquid to be treated moves smoothly, and is specifically about 3 to 6 mm.

An insulating net is preferably disposed between the cylindrical anode and the cylindrical cathode in order to prevent a short circuit therebetween, and the insulating net is preferably a synthetic resin net.
The net-like body is preferably one in which a large number of synthetic resin lines extending in parallel and a large number of synthetic resin lines extending in different directions are crossed and joined.
At the time of the coupling, the synthetic resin lines extending in two different directions are preferably coupled so that both lines have a step, instead of coupling so as to form the same plane.
The reason for this is that it is possible to secure a space through which the liquid to be treated can easily pass between the synthetic resin wire and the electrode.

The structure and installation position of the inlet and outlet formed in the outer cylinder are not particularly limited as long as the liquid to be processed can smoothly pass between both electrodes, and various modes can be adopted. By installing in the tangential direction of the outer cylinder, the liquid to be treated can smoothly flow into the electrolytic apparatus, pass smoothly, and then flow out smoothly.
In addition, about a structure other than the above, a distributor using a slit or a perforated plate can be exemplified.

Further, the installation positions of the cylindrical anode and the cylindrical cathode are not particularly limited. In the illustrated sealed cylindrical electrolysis apparatus 1, the cathode faces both the outer cylinder and the inner cylinder. The reverse may be possible.
Furthermore, the number of cylindrical anodes and cylindrical cathodes disposed in the outer cylinder is not particularly limited, but the liquid to be processed is within a range where the liquid to be processed can pass between both electrodes smoothly and at high speed. It is good, and the range of 3-7 is good for it.
In the illustrated sealed tubular electrolysis apparatus 1, the number of cathodes is one, but the number may be the same as long as the two electrodes are alternately arranged.

The whole outline in the state where the sealed cylindrical electrolysis device of the present invention was assembled is shown. The cylindrical anode and cylindrical cathode used for the sealed cylindrical electrolyzer of the present invention are shown. All the parts used for the sealed cylindrical electrolysis apparatus of the present invention are shown, and the outer cylinder and the inner cylinder are shown in a state where both cylinders are inserted, and the outer cathode, the inner cathode and the anode are inserted. The state is illustrated.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Sealed cylindrical electrolysis apparatus 2 Cylindrical outer cylinder 3 Inlet 4 Outlet 5 Flange 6 Cylindrical inner cylinder 7 Packing 8 End plate 9 O-ring 10 Holding plate 11 Cylindrical anode 12 Flange-shaped power supply plate 13 Outer cathode 14 Flange Inner power supply plate 15 inner cathode 16 flange-shaped inner power supply plate 17 joining ring 18 outer insulating net 19 inner insulating net 20 through hole 21 power cable mounting hole

Claims (4)

An outer cylinder having flanges at both ends, a liquid inlet at one end and a liquid outlet at the other end, an inner cylinder arranged concentrically in the outer cylinder, and a cylinder arranged concentrically alternately with a narrow gap A cylindrical anode and a cylindrical cathode, a flange-shaped power supply plate formed at one end of the anode, a flange-shaped power supply plate formed at the end of the cylindrical cathode opposite to the one end, and an inner Narrow the gap between the cylinder and the innermost electrode and the gap between the outer cylinder and the outermost electrode, and connect the flange-shaped power feeding plate of the anode and the flange-shaped power feeding plate of the cathode to the corresponding flanges at both ends of the outer cylinder. A sealed cylindrical electrolyzer characterized by being assembled and assembled. Through holes are formed in the same positions of the flange-shaped power supply plate of the cylindrical anode and the flange-shaped power supply plate of the cylindrical cathode and the corresponding flanges at both ends of the outer cylinder, and the flanges of the cylindrical anode are formed by bolts through the holes and nuts. The sealed tubular electrolytic apparatus according to claim 1, wherein the flange-shaped power supply plate of the cylindrical power supply plate and the cylindrical cathode and the corresponding flanges at both ends of the outer cylinder are combined. The sealed cylindrical electrolyzer according to claim 1 or 2, wherein the liquid inlet and the liquid outlet are coupled in a tangential direction of the outer cylinder. The hermetic cylindrical electrolyzer according to claim 1, 2, or 3, wherein an insulating net is disposed between the cylindrical anode and the cylindrical cathode.

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