JP2006225694A - Electrolysis cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a current efficiency from being lowered due to a short circuit or a non-moving portion of an electrolyte when a liquid is passed in an electrolytic cell incorporating a circular electrode.
SOLUTION: Circular electrodes 15, 15 are arranged to face each other with a gap between them, an electrode chamber 18 is formed by surrounding the gap periphery with a peripheral wall 6a, and an electrolyte inlet 16 is opened in a part of the peripheral wall. In addition, an electrolytic solution discharge port 17 is opened in the other part, and the electrolytic solution is passed from the electrolytic solution introduction port 16 through the electrolytic solution discharge port 17 to the electrode chamber 18. The electrolyte solution is diverted into the flow path 16a in the vicinity of the electrolyte solution introduction port 16 so that the electrolyte solution introduced into the electrode chamber 18 through the electrolyte solution introduction port 16 spreads in the entire width direction of the electrode, and is radially directed toward the downstream side. Introductory side guide members 25 and 26 are provided for guiding the above. The electrolytic solution flows smoothly and evenly in the electrode chamber 18 to prevent the short circuit of the liquid flow and the generation of the immobile portion, thereby efficiently performing the electrolytic reaction.
[Selection] Figure 2

Description

  The present invention relates to an electrolysis cell which is used for an organic matter decomposition treatment of an organic substance-containing aqueous solution, an oxidative substance accompanying water decomposition, and particularly suitable for an electrochemical treatment such as industrial wastewater.

Conventionally, metal has been used as an electrode material used for the electrolysis of wastewater, but in recent years, electrolysis using a polycrystalline diamond doped with boron as an electrode has attracted attention (for example, Patent Document 1, (See Patent Document 2 etc.).
The polycrystalline diamond electrode is very chemically and electrically stable due to the nature of diamond and can generate various oxidants by its wide potential window, making it suitable for organic decomposition and sterilization. . For this reason, application to water treatment, such as the treatment of persistent organic wastewater and sterilization treatment, is expected.

  The conductive diamond electrode is often manufactured by crystal growth using CVD, and it is difficult to take a complicated electrode shape like the metal electrode that has been used for the electrolytic treatment of waste water until now. In addition, since the conductive diamond electrode is generally more expensive than the metal electrode, in order to obtain a larger electrode area, it is desirable to have an electrolytic cell structure applied to the maximum shape that can be manufactured by CVD, As a result, circular electrodes are often used.

Incidentally, it is known that the electrolysis reaction has a higher electrolytic treatment effect as the linear velocity of the treatment liquid on the electrode surface increases (Non-Patent Document 1). This is because the reaction rate of the electrolysis reaction is controlled by mass transfer to the electrode surface, and by increasing the linear velocity of the treatment liquid, there is little inhibition of the electrode reaction due to the gas generated during the electrolytic treatment remaining on the electrode surface. It is to become. For this reason, the circular electrodes are placed opposite to each other with a gap, an electrode chamber is formed around the periphery of the gap, and a treatment solution is passed through the electrode chamber to improve electrolysis efficiency. Yes.
Japanese Patent Laid-Open No. 7-299467 JP 2000-226682 A Nobuaki Ishihara, Muneo Tanaka, Isao Kamiko, Toshiji Nakahara, “Thermal Power Plant”, Vol. 51 (2000) 1711-1717

  However, in an electrolytic cell incorporating a circular electrode, if the linear velocity of the treatment liquid is too high, the electrolytic treatment effect may be reduced. As the linear velocity increases, a short circuit of the liquid flow occurs inside the cell. On the other hand, hydrogen and oxygen gas generated by electrolysis stays in the fixed part, resulting in blinding of the electrode surface. This is probably because the effective electrode area has decreased. In addition, when such a phenomenon occurs, there is a problem in that the current density varies in the electrode, which may cause partial deterioration on the electrode surface.

  In the present invention, when an electrode made of conductive diamond or the like manufactured by CVD has a circular shape, an electrolytic cell structure for effectively utilizing the electrode area and performing electrolytic treatment efficiently is provided. With the goal.

  That is, in the electrolysis cell of the present invention, the invention according to claim 1 is configured such that the circular electrodes are opposed to each other with a gap, and the circumferential edge of the gap is surrounded by a peripheral wall to form an electrode chamber. The electrolyte inlet is opened in a part of the peripheral wall, the electrolyte outlet is opened in the other part of the peripheral wall, and the electrolyte is introduced into the electrode chamber from the electrolyte inlet through the electrolyte outlet. The electrolyte solution is configured to pass through, and the electrolyte solution introduced into the electrode chamber through the electrolyte solution introduction port spreads in the flow channel near the electrolyte solution introduction port so as to spread in the entire width direction of the electrode. An introduction-side guide member is provided, which diverts the electrolyte and guides it radially toward the downstream side.

  According to a second aspect of the present invention, there is provided an electrolysis cell according to the first aspect, wherein the electrolysis cell flows in the flow path near the electrolyte outlet from the entire width direction of the electrode toward the electrolyte outlet. A discharge-side guide member is provided that guides the liquid toward the downstream side by converging the liquid toward the downstream side.

  According to a third aspect of the present invention, there is provided the electrolysis cell according to the first or second aspect, wherein the introduction side guide member comprises a plurality of guide members, and the guide deflection angle of the guide member on the central side in the flow path width direction is reduced. The guide deflection angle of the guide member on the side in the width direction is increased.

  According to a fourth aspect of the present invention, there is provided the electrolysis cell according to any one of the first to third aspects, wherein the electrode is a conductive diamond electrode.

  According to the present invention, the electrolytic solution introduced into the electrolyte from the electrolytic solution introduction port is diverted by the introduction-side guide member, is surely spread in the entire width direction of the electrode, and is guided to flow downstream. Generation of a short circuit and a stationary part is effectively prevented. As a result, hydrogen, oxygen, and the like generated by electrolysis on the electrode surface can be efficiently discharged from the electrode surface to cause an even and efficient electrolytic reaction.

  Further, in addition to the guide member on the introduction side, the electrolyte solution outlet is converged toward the downstream side by converging the electrolyte flowing from the entire width direction of the electrode toward the electrolyte solution outlet side toward the electrolyte solution outlet side. If provided, the flow of the electrolytic solution can be made smoother and discharged to the outside of the electrolyte, and the occurrence of a short-circuit portion and a non-moving portion due to the disturbance of the flow of the electrolytic solution can be further reliably prevented.

  In the present invention, the electrolysis chamber is configured by placing at least two electrodes facing each other with a gap, but the number of electrodes placed facing each other with a gap is not particularly limited, An electrode chamber is formed between the electrodes, and the guide member can be arranged in each electrode chamber. Further, the electrolyte solution inlet and the electrolyte outlet that are opened in the peripheral wall of the electrolysis chamber do not particularly define the positional relationship with each other, but are preferably positions facing each other in the radial direction.

  Further, the guide member can be constituted by, for example, a plurality of guide plates arranged along the flow path, and controls the flow of the electrolyte by deflecting the electrolyte flowing through the flow path according to the arrangement angle of the guide plate. be able to. When there are a plurality of guide members, the guide deflection angle of the guide member on the center side in the flow path width direction is reduced, and the guide deflection angle of the guide member on the end portion in the width direction is increased, so that the width direction of the electrode The electrolyte can be spread and flowed throughout.

  In the present invention, it can be applied as suitable for an electrolysis cell using diamond electrodes, but the present invention is not limited to those using diamond electrodes, and other types of electrodes can be used. The same applies to the electrolysis cell used. The electrode shape may be circular, and is not limited to a perfect circle, but includes a circular shape such as an ellipse. Moreover, when using a diamond electrode, although normally manufactured by CVD, in this invention, it does not specifically limit about the manufacturing method.

  As described above, according to the electrolysis cell of the present invention, the circular electrodes are arranged to face each other with a gap therebetween, and the circumferential edge of the gap is surrounded by a peripheral wall to form an electrode chamber. The electrolyte solution inlet is opened in a part of the electrode, the electrolyte solution outlet is opened in the other part of the peripheral wall, and the electrolyte solution is passed from the electrolyte solution inlet to the electrode chamber through the electrolyte solution outlet. And the electrolyte solution is introduced into the flow path in the vicinity of the electrolyte solution introduction port so that the electrolyte solution introduced into the electrode chamber through the electrolyte solution introduction port spreads in the entire width direction of the electrode. Since an introduction side guide member is provided that diverts and guides radially toward the downstream side, the electrolyte smoothly flows over the entire electrode surface in the electrode chamber, causing short circuit of the liquid flow and generation of immobile parts. It is effectively prevented and an efficient electrolytic reaction is performed. In addition, current density on the electrode surface is less likely to occur, and partial wear of the electrode is prevented. Furthermore, since gas stagnation and the like are effectively prevented, the electrolytic treatment effect can be further enhanced by increasing the linear velocity of the treatment liquid.

Below, one Embodiment of this invention is described based on FIGS. 1-3.
The electrode housing is configured by arranging the divided electrode housings 1a and 1b so as to face each other with eight gaskets 5 ... 5 and seven insulating spacers 6 ... 6 alternately interposed therebetween. 1b is clamped by end plates 7a and 7b from both sides and fixed by a tie rod 8 and a nut 9. In addition, on both end sides (upper and lower end portions in FIG. 1) of the divided electrode housings 1a and 1b, through-holes that respectively constitute the water passages 2a, 2b, 3a, and 3b are formed. In this embodiment, a sealing screw is screwed into one of the water passages 2a, 2b, and a sealing screw is screwed into one of the water passages 3a, 3b, and one of the water passages 2a, 2b. The water passages 3a and 3b are configured to pass water.

  In addition, circular grooves are formed in the concave portions of the facing portions of the divided electrode housings 1a and 1b, respectively, and a power feeding plate 10 made of a conductive metal such as a disk is formed so as to fit into the circular grooves. 11 are installed. O-rings 32 and 33 made of fluororesin or the like are arranged so as to be slightly larger than the power supply plates 10 and 11 and surround the periphery. The inner surfaces of the power supply plates 10 and 11 and the inner surfaces of the other divided electrode housings 1a and 1b are substantially flush with each other and are in contact with the gaskets 5 located on the outermost sides.

Each of the gaskets 5 ... 5 has a thin plate shape as shown in FIG. 3, and a circular hole 5a having a size slightly larger than the size of a circular electrode to be described later is formed at the center thereof. A bulging hole 5b is formed which bulges up and down in the vertical direction from the upper and lower ends of the hole 5a and surrounds the periphery of the water passages 2a ... 3b.
Further, the spacer 6 has a flat plate shape as shown in FIG. 3, and has a thickness for setting a gap between electrodes described later. The spacer 6 is formed with a circular hole 6a having a size slightly smaller than the size of a circular electrode, which will be described later, at the center thereof, and swells in a mountain shape in the vertical direction from the upper and lower ends of the circular hole 6a. A bulging hole 6b that surrounds the periphery of the water passages 2a ... 3b is formed, and the bulging hole 6b has a slightly smaller shape than the bulging hole 5b. Each spacer 6 is formed with a positioning through hole at a common position. When the spacers 6 are laminated between the divided electrode housings 1a and 1b, positioning is performed by passing the positioning pins 12 through the through holes. ing.

  Inside the power feeding plates 10 and 11, circular anodes 13 and cathodes 14 having a diameter slightly smaller than the circular hole 5a of the gasket 5 and slightly larger than the O-rings 32 and 33 are electrodes. It is bonded with a conductive resin or the like. Shaft-shaped power feeding portions 20a and 20b connected to the centers of the conductive plates 10 and 11 pass through the electrode divided housings 1a and 1b and the end plates 7a and 7b. It is covered with cylindrical insulating pipes 21a and 21b. The exposed portions of the power feeding units 20a and 20b outside the end plates 7a and 7b are covered with the terminal boxes 22a and 22b, and a DC power source (not shown) is connected thereto.

  The spacer 6 is located inside the anode 13 and the cathode 14, and the circular hole 6 a is located slightly inside the anode 13 and the cathode 14. Another gasket 5 is located inside the spacer 6, and a circular bipolar electrode 15 is disposed as an electrode on the inner peripheral side of the circular hole 5 a of the gasket 5. The bipolar electrodes 15 are arranged with a gap corresponding to the thickness of the spacer 6. By repeating the above arrangement, six bipolar electrodes 15 are arranged inside the anode 13 and the cathode 14 with a gap corresponding to the thickness of the spacer 6. The anode 13, the cathode 14, and the bipolar electrodes 15... 15 can be composed of diamond electrodes doped with a predetermined amount of boron or nitrogen during the synthesis of diamond to impart conductivity. In particular, the anode is preferably a diamond electrode. If the doping amount is too small, technical significance does not occur. If the doping amount is too large, the doping effect is saturated. Therefore, a doping amount in the range of 50 to 20,000 ppm with respect to the carbon amount of diamond is suitable. The present invention is not limited to diamond electrodes, but may be made of other materials such as Pt and Pb, and the anode, cathode and bipolar electrodes may be made of different materials. May be. Moreover, in this invention, a bipolar electrode may not be provided but all the electrodes may be connected to a power supply.

  The gap between each electrode is surrounded by the inner peripheral wall of the circular hole 6a of the spacer 6 to form the electrode chamber 18, and the connecting portion between the circular hole 6a and the bulging hole 6b is the electrolyte introduction. A mouth 16 and an electrolyte outlet 17 are formed. The spaces surrounded by the inner peripheral wall of the bulging hole 6b and continuing to the water passages 2a... 3b constitute an electrolytic solution introduction channel 16a and an electrolytic solution discharge channel 17a, respectively. The electrolytic solution introduction channel 16a, the electrolytic solution discharge port 17, and the electrolytic solution discharge channel 17a face each other in the radial direction.

  In the electrolytic solution introduction channel 16 a, two wall-plate-like introduction-side guide members 25, 25 are provided in the vicinity of the electrolytic solution introduction port 16 and in the center in the width direction of the flow channel. They are arranged with gaps facing each other in a straight direction. That is, the guidance change angle is set to 0 degrees. Further, on the outside of the introduction side guide members 25, 25, wall side plate-like introduction side guide members 26, 26 are arranged with a gap from the introduction side guide member 25. The inside 26 of the introduction side guide part has an inner side surface that is straight along the direction of the electrolyte discharge port 17, and the inner front end face has a guide deflection angle that faces obliquely outward (end part in the electrode width direction). Further, the outer side surface of the introduction side guide member 26 has a large guide deflection angle directed toward the end in the width direction of the electrode. The arrangement and shape of the introduction side guide members 25 and 26 are configured such that the electrolyte introduced into the electrode chamber through the electrolyte introduction port 16 is guided radially so as to spread in the entire width direction of the electrode.

On the other hand, in the electrolyte solution discharge channel 17a, two wall-plate-shaped discharge side guide members 27, 27 are provided in the vicinity of the electrolyte solution discharge port 17 and in the center in the width direction of the channel. They are arranged in a straight line in 16 directions with a gap therebetween. Further, discharge-side guide members 28 and 28 are disposed outside the discharge-side guide member 27 with a gap from the discharge-side guide member 27. The inside 28 of the guide part has an inner side faced straight in the direction of the electrolyte introduction port 16, and an inner front end face has a guide deflection angle directed toward the end part in the width direction of the electrode.
Further, the outer side surface of the discharge side guide member 28 has a guide deflection angle directed toward the end in the width direction of the electrode. The arrangement and shape of the discharge-side guide members 27 and 28 are such that the electrolyte discharged from the electrode chamber through the electrolyte discharge port 16 flows from all over the width direction of the electrode, converges, and is guided to the electrolyte discharge port 16. Configured as follows.
The guide members 25 ... 28 have substantially the same thickness as the gap between the electrodes, and the entire amount of the electrolyte flowing through the electrolyte solution introduction channel 16a and the electrolyte solution discharge channel 17a is to be guided. Yes.

Each guide member 25 ... 28 is disposed between each electrode, and is positioned and fixed by positioning pins 30 and 30 penetrating in the axial direction. O-rings 31 ... 31 are arranged.
The electrolysis cell of one embodiment of the present invention is constituted by the above.

Next, the operation of the electrolysis cell will be described.
The electrolytic solution flowing into the water passage 2a or 2b (for example, the water passage 2a) flows into the electrolytic solution introduction flow channel 16a and flows into the electrolytic solution introduction port 16 between the electrodes. At that time, the electrolytic solution is diverted by the introduction-side guide members 25 and 26, the central-side electrolyte solution is straightly guided by the introduction-side guide member 25, and the outer-side electrolyte solution is introduced by the introduction-side guide member. After being guided straight between 25 and the introduction side guide member 26, it is guided so as to spread outward. In addition, the electrolyte divided into the outside of the introduction side guide member 26 is guided so as to spread outward by the guide deflection angle of the outside surface of the introduction side guide member 26. By the action of the introduction guide members 25 and 26, the electrolytic solution is guided radially so as to spread in the entire width direction of the electrode, and the electrolytic solution smoothly flows over the entire surface of the electrode. In the downstream area of the electrode chamber 18, the electrolyte flows toward the electrolyte outlet 16 while being regulated by the inner peripheral wall of the spacer 6. In the electrolytic solution discharge port 17, the electrolytic solution flowing outside the electrode is guided toward the electrolytic solution discharge port 17 by the discharge side guide member 28, and on the inner side of the electrolyte solution discharge port 17 by the discharge side guide members 27 and 28. The electrolyte that is guided toward 17 and flows through the center of the electrode flows between the discharge-side guide members 27 and 27 toward the electrolyte outlet 17. Due to the action of the discharge side guide members 27, 28, the electrolytic solution flowing in the entire width direction of the electrode is quickly discharged from the electrolytic solution discharge port 17 so as to converge toward the electrolytic solution discharge port 17. The The electrolytic solution discharged from the electrolytic solution discharge port 17 is sent to the outside through the water passage 3a or 3b (for example, the water passage 3b) through the electrolytic solution discharge passage 17a. As described above, the electrolytic solution is smoothly passed through the electrode chamber 18. In this case, the liquid flow rate is preferably 1 to 10,000 m / hr.

When the electrolyte solution is passed, current is passed between the anode 13 and the cathode 14 from a DC power source (not shown) through the power feeding units 20a and 20b. Then, the bipolar electrodes 15 ... 15 are polarized, and anodes and cathodes appear at predetermined intervals. In each electrode chamber 18, an electrolysis reaction with respect to the electrolytic solution occurs due to this energization. When the electrolytic solution is an organic substance-containing aqueous solution, the organic substance decomposition treatment is effectively performed by electrolysis.
In addition, when the electrolytic solution is passed, since the gas smoothly flows over the entire surface of the electrode, the gas generated by the electrolysis reaction does not stay and the reaction is efficiently performed. Further, since the current density is less likely to occur, partial wear of the electrode can be prevented.
As mentioned above, although this invention was demonstrated based on the said embodiment, this invention is not limited to description of the said embodiment, A change is possible within the scope of the present invention.

Next, an embodiment of the present invention will be described in comparison with a comparative example.
An electrolysis cell constituted by changing the number of electrodes of the electrolysis cell described in the above embodiment to 3 was prepared, and the water treatment apparatus shown in FIG. 4 was constructed. Each electrode was constituted by a circular diamond electrode having a diameter of 100 mm and a thickness of 0.5 mm, and had a distance of 5 mm from each other.
The water treatment apparatus includes a water storage tank 41 for storing treated water 40, a liquid feed pipe 42 and a liquid feed pump 43 for supplying treated water from the water storage tank 41 to the water passage 2a or 2b of the electrolysis cell, A return pipe 44 for returning treated water drained from the water passage 3a or 3b of the electrolysis cell to the water storage tank 41 is provided, and the treated water can be circulated and reacted by the electrolytic reaction cell by the above configuration.
Moreover, as a comparative example, an electrolysis cell having the same configuration as in the above example was prepared except that the guide members 25 to 28 were not provided, and a water treatment apparatus was configured in the same manner as described above.

The treated water contains sodium sulfate which is a supporting electrolyte and 1000 mg / l as TOC of polyethylene glycol. 5 l of this was used for batch processing.
The amount of current input from the DC power source was 14 A, the flow rate of the treatment liquid to the electrolysis cell was 2000 l / hr, and the effects of electrolytic treatment with and without the guide member were compared. The test results are shown in FIG.
As is apparent from FIG. 5, it was found that the use of an electrolysis cell having a guide member increases the electrolytic treatment effect as compared to the case of using an electrolysis cell not provided with a guide member.

It is front sectional drawing of one Embodiment of this invention. It is the side view and side sectional drawing similarly. It is an exploded perspective view similarly. It is the schematic of the water treatment apparatus in the Example of this invention. It is a figure which similarly shows the test result in an Example.

Explanation of symbols

1a, 1b Divided electrode housing 2a, 2b Water passage 3a, 3b Water passage 5 Gasket 6 Spacer 6a Circular hole 6b Swelling hole 13 Anode 14 Cathode 15 Bipolar electrode 16 Electrolyte introduction port 16a Electrolyte introduction passage 17 Electrolyte discharge Exit 17a Electrolyte discharge flow path 18 Electrode chamber 25 Introduction side guide member 26 Introduction side guide member 27 Discharge side guide member 28 Discharge side guide member

Claims (4)

  Circular electrodes are arranged to face each other with a gap between them, an electrode chamber is formed by surrounding the circumferential edge of the gap with a peripheral wall, and an electrolyte inlet is opened in a part of the peripheral wall. An electrolyte outlet is opened in a part of the electrolyte, and the electrolyte is passed from the electrolyte inlet to the electrode chamber through the electrolyte outlet, and in the vicinity of the electrolyte inlet. An introduction side guide that guides radially toward the downstream side by diverting the electrolyte solution so that the electrolyte solution introduced into the electrode chamber through the electrolyte solution introduction port spreads in the entire width direction of the electrode. An electrolysis cell comprising a member.   Discharge that guides the electrolyte solution to the electrolyte solution outlet by converging the electrolyte flowing from the entire width direction of the electrode toward the electrolyte solution outlet toward the downstream side in the flow path near the electrolyte outlet. The electrolysis cell according to claim 1, wherein a side guide member is provided.   The introduction side guide member is composed of a plurality, wherein the guide deflection angle of the guide member on the central side in the flow path width direction is reduced, and the guide deflection angle of the guide member on the width direction end side is increased. Item 3. The electrolysis cell according to Item 1 or 2.   The electrolysis cell according to claim 1, wherein the electrode is a conductive diamond electrode.

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