JP2997267B1 - Non-diaphragm electrolyzer - Google Patents

Abstract

Abstract: PROBLEM TO BE SOLVED: To drastically reduce the frequency of maintenance for electrode scale adhesion in a diaphragmless electrolytic device without hastening the aging of the electrode. Try not to happen. SOLUTION: The electrode plate widths 11 of a cathode plate 9 and an anode plate 10 are both 50 mm or more and 200 mm or less. A plurality of the cathode plates 9 and the anode plates 10 are arranged in parallel and alternately, and the interval 12 between the arranged cathode plates 9 and the anode plates 10 is set to be three times or more and five times or less the electrode thickness 13. The gap between the electrode plates of the anode 9 and the cathode 10 is sandwiched and sealed with a rubber gasket having a reinforcing member therein.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a diaphragmless electrolysis apparatus having a parallel plate type electrolytic cell for electrolyzing water with a diaphragm, and more particularly to a parallel plate type electrolytic cell for electrolyzing seawater or salt water with a diaphragm. The present invention relates to a diaphragmless electrolysis apparatus having the same and a rubber gasket used for the same.

[0002]

2. Description of the Related Art Conventionally, a non-diaphragm type electrolysis apparatus having a plurality of electrode plates arranged in parallel and in which an electrolytic solution is directly flowed between the electrodes of the electrode plates has been widely used. Such non-diaphragm electrolyzers produce sodium hypochlorite by electrolyzing water, seawater, etc., and use it for sterilization of tap water and sewage, or that sodium hypochlorite paralyzes marine life. Utilizing its action, it is injected into the seawater utilization system to prevent marine organisms from adhering.

The above diaphragmless electrolyzers are roughly classified into a feeder type electrolyzer and a gasket seal type electrolyzer. In any of the electrolyzers, in the case of a large electrolyzer having a wide electrode width, the current flowing through the electrode surface is large. However, since the electrodes tend to generate heat, the thickness of the electrode plate must be increased.

However, when an electrolytic solution containing a hard component such as seawater is generally electrolyzed with a diaphragm, the pH of the cathode surface increases due to the alkali generated at the cathode, and calcium ions and magnesium ions in seawater are removed at the cathode surface. Ca
Hydroxides such as (OH) ₂ and Mg (OH) ₂ adhere and adhere and grow as time elapses to form scales, which hinder electrolysis, reduce the electrolytic performance between the electrodes, and reduce the electrode life. Will be shortened,
This tendency is further promoted by increasing the thickness of the electrode plate.

That is, when seawater flows in from the inlet,
This seawater hits the tip of the electrode and divides the flow between the front and back surfaces of the electrode, flows between the poles and heads for the outlet, but if the electrode plate is thick, a vortex occurs at the tip of the electrode, and in the vortex part Since the flow of the seawater temporarily stops and the flow velocity decreases, the PH of the seawater tends to increase. When the pH rises, the scale further grows to cover the electrodes, and the current density and the cell voltage of the electrolyzer increase, and the power consumption for electrolysis increases. Also, if the scale grows to cover the entire electrode, the seawater becomes difficult to flow, generating heat and
Problems such as electrode damage occur.

Therefore, it is necessary to remove this scale, but generally, the phase of the voltage applied to the anode and the cathode is intermittently inverted to electrically elute the scale attached to the cathode, or Dissolving the scale with an acid such as hydrochloric acid or oxalic acid (acid washing) is performed. The former can reduce the maintenance and maintain the initial performance, but has the problem of accelerating the aging of the electrode. The latter requires acid cleaning once a month to maintain the initial performance. There is a problem in that it needs to be performed at a frequent frequency, and maintenance requires considerable labor and cost.

On the other hand, in the conventional gasket seal type electrolytic cell (FIGS. 8 to 10), when the electrode width 81 is set to 50 mm or more, the current flowing through the electrode increases, and the electrode generates heat as the scale grows. As shown in FIG. 9, when the bolt hole 83a is located at the center of the rubber gasket 82, heat is trapped in the seal portion 84 of the rubber gasket 82 because the electrodes 80 and 89 are not cooled. There is a possibility that. Further, if a rubber gasket 82 is arranged inside a bolt 83 as in a gasket-seal type electrolytic cell (FIGS. 11 to 13) as shown in FIG.
3, the rubber gasket 82 cannot be evenly tightened, and as shown in FIG. 13, the rubber gasket 82a may bend in a bow shape and a sealing failure may occur.

[0008]

SUMMARY OF THE INVENTION The present invention relates to a diaphragmless electrolysis apparatus capable of greatly reducing the frequency of maintenance without accelerating the aging of the electrode, and furthermore, an electrode which generates heat in a gasket-sealed electrolytic cell. The present invention provides a gasket that does not cause gasket sealing failure.

[0009]

According to the present invention, a plurality of anode and cathode electrode plates are arranged in parallel and alternately, and the voltages applied to the anode and cathode electrode plates are always in phase. In a diaphragm-free electrolysis apparatus in which seawater flows between electrodes of a certain electrolytic cell, the width of the electrode plate is 50 mm or more and 200 mm or less, and the electrode plate interval is 3 times or more and 5 times or less of the electrode plate thickness. It is characterized by the following.

"Plurality" of "plurality of anode and cathode electrode plates"
Is not particularly limited as long as it is the number of electrode plates usually used in a diaphragm-free electrolytic device, but each is 5 to 50.
Sheets are preferred. The anode is preferably an insoluble anode plated with platinum or the like.

The phrase "voltages applied to the anode and cathode electrode plates are always in phase" means that the phase of the voltage applied to the anode and the cathode is not intermittently inverted.

The term "sea water" does not mean only sea water, but also includes salt water containing a wide range of hard components at a high concentration.

"The width of the electrode plate is 50 mm or more and 200 m or more.
m or less ”means“ − feeder +
The width of the electrode plate held by the power supply from the negative power supply to the positive power supply (reference numeral 11 in FIG. 2), and in the case of a gasket-sealed electrolytic device, one insulating spacer of the electrode portion facing the other insulating spacer. Width (reference numeral 41 in FIG. 4) is 5
It means 0 mm or more and 200 mm or less.

"Electrode plate spacing is at least three times the electrode plate thickness and 5 or more.
The term “less than or equal to twice” refers to the distance between the parallel and alternately arranged anode and cathode electrode plates (reference numeral 12 in FIG. 2 and reference numeral 4 in FIG. 4).
2) is not less than 3 times and not more than 5 times the thickness of the anode or cathode electrode (reference numeral 13 shown in FIG. 2 and reference numeral 43 shown in FIG. 4). This interval is more preferably 3 times or more and 5 times or less. For example, if the electrode plate thickness is 1 mm, the electrode plate interval is 3 mm to 5 mm, if the electrode plate thickness is 1.5 mm, the electrode plate interval is 4 mm to 7.5 mm, and if the electrode plate thickness is 2 mm, the electrode plate interval is 6 mm to 10 mm. is there.

In a diaphragmless electrolysis apparatus having a structure in which a plurality of anode and cathode electrode plates are arranged in parallel and alternately and a gasket is sandwiched between the two electrode plates and sealed, a rubber gasket between the anode and cathode electrode plates is formed. It may have a reinforcement inside. The “reinforcing body” is not particularly limited as long as it appropriately reinforces the rubber without breaking the rubber and gives strength to the gasket. For example, FRP (fi
ber reinforced plastics), FRTP (fiber reinfor
ced thermoplastics), stainless steel 304, and metals such as iron and aluminum. The “reinforcement” may be exposed on the surface of the rubber gasket on the non-wetted side, or may be completely embedded in the rubber gasket.

Further, the rubber gasket may have a structure in which the bolt holes are disposed at the center or a structure in which the rubber gaskets are disposed inside the bolt holes. It is more preferable to dispose a rubber gasket inside the bolt hole, because it is possible to further reduce heat buildup in a sealing portion between the rubber gasket and the electrode. When the reinforcing member is exposed on the surface of the rubber gasket, it is preferable to turn the side where the reinforcing member is exposed to the bolt side in order to effectively exert the strength.

[0017]

According to the diaphragm-free electrolysis apparatus of the present invention, since the width of the electrode plates is 50 mm or more and 200 mm or less and the interval between the electrode plates is 3 times or more and 5 times or less of the electrode plate thickness, the scale adheres. The area can be limited only to the part along the insulating spacer and the corner of the electrode on the seawater inlet side.It also prevents scale growth on the electrode surface and dramatically reduces the frequency of maintenance such as acid cleaning. Can be reduced.

That is, since the interval between the electrode plates is set to be not less than 3 times and not more than 5 times the thickness of the electrode plate, seawater does not vortex at the tip of the electrode on the inlet side of the seawater. Since it can flow constantly without stagnation, there is no increase in PH which causes scale growth. In addition, on the electrode surface, alkali is generated at the same time as alkali by the cathodic reaction, hydrogen is generated at the same time, and seawater with a fast flowing flow velocity and calcium generated on the electrode surface due to the film breaking force when the generated hydrogen bubbles leave the electrode surface, There is no scale growth because the magnesium coating is removed. On the other hand, no hydrogen is generated along the insulating spacer,
In addition, since the flow rate of seawater is low, PH rises and scale grows. However, when the scale along the insulating spacer grows by about 5 mm, it is affected by the generation of hydrogen and does not grow any further. Further, if no scale is generated, the heat generation of the electrodes can be suppressed to the minimum necessary, so that it is not necessary to make the electrode plate thicker than necessary, so that an economic effect can be obtained.

In particular, the present invention can reduce the conventional maintenance once a month to once every six months in seawater containing a hard component at a high concentration to which the scale is very likely to adhere. This has an extremely excellent effect that the performance in the initial stage of use can be maintained even twice.

The width of the electrode plate should be 50 mm or more and 200 m or more.
m or less, when the electrode width is 50 mm or less,
The ratio of the scale attached to the insulating spacer portion to the electrode width is large. For example, when the electrode width is 30 mm, the scale of 5 mm adheres to one of the insulating spacers, and the actual electrode width becomes 20 mm, which is practical. This is not the case, and if it is 200 mm or more,
This is because the electrode plate thickness must be larger than 1 mm to 2 mm which is usually used, and this case is not practical.

In a non-diaphragm electrolytic device having a structure in which a plurality of anode and cathode electrode plates are arranged in parallel and alternately, and a rubber gasket is sandwiched between the two electrode plates to seal the electrodes, when the scale grows, the electrodes generate heat. However, if the rubber gasket has a reinforcing body inside the anode and cathode electrode plates, the rubber gasket does not become bow-shaped, so that a sealing failure does not occur.

[0022]

Embodiments of the present invention will be described below in detail with reference to the drawings.

First, a feeder type seawater electrolysis apparatus will be described as a first embodiment of a diaphragmless electrolysis apparatus of the present invention. FIG. 1 is a plan view of a feeder type seawater electrolysis apparatus according to a first embodiment, and FIG. 2 is a cross-sectional view taken along line AA of FIG. (The hatching in the drawings is omitted.) The feeder-type seawater electrolyzer shown in the first embodiment has an electrolytic cell 1 and a lower tank having a seawater inlet 6 at one end below the electrolytic cell 1. 4 and an upper tank 5 having an outlet 7 for seawater electrolyzed at the upper part of the electrolytic cell 1 at one end. The electrolytic cell 1 has a cathode plate 9 and an anode plate 10 parallel to each other. The cathode plate 9 and the anode plate 10 are connected to the -feeder 2 and the + feeder 3, respectively, between the cathode plate 9 and the + feeder 3, and between the anode plate 10 and the -feeder. 2
Is filled with an insulating spacer 8.

Next, the operation of the feeder type seawater electrolysis apparatus will be described. The seawater flowing in the direction of the arrow from the inflow port 6 is rectified in the lower tank 4 and flows upward between the electrode plates 9 and 10 of the electrolytic cell 1. A direct current is supplied from the -feeder 2 and the + feeder 3 to each of the cathode plate 9 and the anode plate 10 housed in parallel with the electrolytic cell 1 so that the seawater is electrolyzed and the sodium hypochlorite Is generated. Therefore, the seawater discharged from the seawater outlet 7 contains sodium hypochlorite, and this seawater is sent into, for example, tap water or sewage and used for sterilization, or injected into a seawater utilization system. It can be used to prevent marine organisms from sticking.

Since seawater contains calcium ions, magnesium ions, and the like, Ca (OH) ₂ , Mg (O)
H) _{2 and the} like are generated, and simultaneously generated hydrogen bubbles grow on the electrode surface and are generated on the electrode surface by the film breaking force generated when leaving the electrode surface and the flow of seawater flowing between the electrodes 9 and 10. Since the coating of Ca (OH) ₂ or Mg (OH) ₂ is removed, no scale is generated. Further, no hydrogen is generated at the electrode portion along the insulating spacer 8, and the PH rises due to the low flow velocity of the seawater on the wall surface, as shown in FIG. 7 (arrows in FIG. 7 indicate the direction in which the seawater flows). The scale 70 is generated at the portion along the insulating spacer 8 and at the corner of the electrode on the seawater inlet side. When the scale 70 grows about 5 mm from the insulating spacer 8 toward the center of the electrode, it is affected by the generation of hydrogen on the electrode surface. , No further growth.

Next, a gasket seal type seawater electrolysis apparatus will be described as a second embodiment of the diaphragmless electrolysis apparatus of the present invention. FIG. 3 is a plan view of a gasket-sealed seawater electrolysis apparatus according to a second embodiment, and FIG. 4 is a cross-sectional view taken along line BB.

A gasket-sealed seawater electrolyzer according to the second embodiment has an electrolytic cell 31, a lower tank 34 having a seawater inlet 36 at one end below the electrolytic cell 31, and an upper part of the electrolytic cell 31. This is a substantially rectangular parallelepiped electrolysis apparatus including an upper tank 35 having an outlet 37 at one end of an electrolyzed seawater. The electrolysis tank 31 includes a cathode plate 39 and an anode plate 40 arranged in parallel and accommodated. 39 and the anode plate 40 are sandwiched and sealed by a rubber gasket 32, and an insulating spacer 38 is filled inside the rubber gasket 32. A bolt hole 33 a through which the bolt 33 passes is provided outside the rubber gasket 32. The rubber gasket 32 may be sandwiched and sealed between the cathode plate 39 and the anode plate 40 as shown in FIG. 5, or may be sealed as shown in FIG.
0 (or the cathode plate 39) may be located rearward from the bolt 33, and the gap may be sandwiched between the cathode plate 39a and the cathode plate 39b for sealing. The rubber gasket 32 has a reinforcing member 4 inside.
5, the reinforcing member 45 may be exposed on the bolt 33 side of the rubber gasket 32 as shown in FIG. 5, or may be completely embedded in the rubber gasket 32 as shown in FIG. good. Reinforcing member 45 is rubber gasket 32
If the rubber gasket 32 is arranged so that the bolt 33 comes into contact with the portion where the reinforcing member 45 is exposed as shown in FIG. Can be raised more.

The operation of the gasket-sealed seawater electrolyzer shown in the second embodiment is the same as that of the first embodiment except that a current is directly applied to each of the cathode plate 39 and the anode plate 40. The operation is the same as the operation of the feeder type seawater electrolysis apparatus shown.

An example using the feeder type seawater electrolysis apparatus according to the first embodiment will be described below.

(Embodiment 1) In a feeder type seawater electrolysis apparatus having an electrode width 11 of 100 mm and an electrode height 14 of 480 mm, the flow rate between seawater electrodes was 1 m / s, and the electrode plate thickness of the cathode plate 9 and the anode plate 10 was When the thickness of each of the electrodes 13 was 1 mm, the amount of the scale adhered was examined by changing the distance 12 between the electrode plates. FIG. 14 is a graph showing the change over time in the amount of scale attached when the electrode plate thickness is 1 mm. Electrode plate interval 12 is 2mm
In the case of (two times the electrode plate thickness), the amount of scale attached increased with time, and as much as 300 g of scale adhered in about eight weeks, but the electrode plate interval 12 was 3 mm (three times the electrode plate thickness). ,
4 mm (4 times the electrode thickness), 5 mm (5 times the electrode thickness)
In the case of, the amount of scale adhered became constant after about 4 weeks, and did not grow any more. The amount of scale adhered was about 100 g even after 8 weeks, and compared with the case where the electrode plate thickness was doubled. As a result, the amount of adhered scale was only about one third.

(Embodiment 2) Electrode width 11, electrode height 14,
The seawater flow rate between the electrodes was the same as in Example 1, the electrode plate thickness 13 of each of the cathode plate 9 and the anode plate 10 was 1.5 mm, and the distance between the electrode plates 12 was changed to examine the amount of scale adhesion. FIG. 15 is a graph showing the change with time of the amount of adhered scale when the electrode plate thickness is 1.5 mm. Electrode plate interval 12 is 2m
m (approximately 1.3 times the electrode plate thickness) and 3 mm (2 times the electrode plate thickness), the amount of scale attached increases with time. 300g, 2mm
In the case of, as much as 450 g of scale adhered, but 4.5 g
mm (three times the electrode plate thickness), the amount of the scale adhered was constant in about 4 weeks, did not grow any more, and the amount of scale adhered was about 100 g even after 8 weeks. The amount of scale attached is only about 1/5 to 1/4 as compared with the case where the plate thickness is 1.3 times, and only about 1/3 as compared with the case where the electrode plate thickness is 2 times. Did not.

(Embodiment 3) Electrode width 11, electrode height 14,
The seawater flow rate between the electrodes was the same as in Example 1, the electrode plate thickness 13 of the cathode plate 9 and the anode plate 10 was set to 2 mm, and the electrode plate interval 12 was changed to examine the amount of scale adhesion. FIG. 16 is a graph showing the change over time in the amount of scale attached when the electrode plate thickness is 2 mm. The electrode plate interval 12 is 4 mm (approximately 2
Times) and 5 mm (2.5 times the electrode plate thickness), the amount of scale attached increases with time, and 300 g for 5 mm and 450 g for 4 mm in about 8 weeks.
6mm (three times the electrode plate thickness)
In the case of, the amount of scale adhered was constant in about 4 weeks, did not grow any more, the amount of scale adhered was less than 150 g even after 8 weeks, and compared to the case where the electrode plate thickness was doubled. As a result, the amount of adhered scale was about one third, and was only about one half as compared with the case where the electrode plate thickness was 2.5 times.

(Embodiment 4) The electrode width 11 was set to 50 mm,
The other conditions were the same as in Examples 1 to 3 to examine the amount of scale attached. The experimental results showed the same tendency as in Examples 1 to 3, and the absolute amount of the scale was almost the same.

(Example 5) The flow rate between sea electrodes was set to 2.5 m / s, which is the upper limit of the economic flow rate, and the other conditions were the same as in Examples 1 to 3 to determine the amount of scale adhesion. Was. The experimental results showed the same tendency as in Examples 1 to 3, and the absolute values of the amounts of the attached scales were all reduced to about half.

Although the above-described embodiment has been described with respect to the feeder type seawater electrolyzer, the present invention is not limited to the feeder type seawater electrolyzer, and all the non-diaphragm type electrolyzers including the gasket seal type seawater electrolyzer can be used. It can be applied to

[Brief description of the drawings]

FIG. 1 is a plan view of a feeder type seawater electrolysis apparatus according to a first embodiment.

FIG. 2 is a sectional view taken along line AA of the feeder type seawater electrolysis apparatus according to the first embodiment.

FIG. 3 is a plan view of a gasket-sealed seawater electrolysis apparatus according to a second embodiment.

FIG. 4 is a sectional view taken along line BB of a gasket-sealed seawater electrolysis apparatus according to a second embodiment.

FIG. 5 is an enlarged view showing a gasket and a bolt of the apparatus of FIG. 4;

FIG. 6 shows still another modification of the second embodiment in FIG.
Fig.

FIG. 7 is a side cross-sectional view showing a scale attached to a feed-type seawater electrolysis apparatus.

FIG. 8 is a cross-sectional view of a conventional gasket-sealed seawater electrolysis apparatus.

FIG. 9 is an enlarged configuration diagram showing a gasket and a bolt of the apparatus of FIG. 8;

FIG. 10 is a plan view of the apparatus of FIG. 8;

FIG. 11 is a cross-sectional view of another conventional gasket-sealed seawater electrolysis apparatus.

FIG. 12 is a configuration diagram showing a gasket and a bolt of the apparatus of FIG. 11 in an enlarged manner.

FIG. 13 is a plan view of the apparatus of FIG. 11;

FIG. 14 is a graph showing the change over time in the amount of scale attached when the electrode plate thickness is 1 mm.

FIG. 15 is a graph showing the change over time in the amount of scale attached when the electrode plate thickness is 1.5 mm.

FIG. 16 is a graph showing the change over time in the amount of scale attached when the electrode plate thickness is 2 mm.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electrolyzer 9 Cathode plate 10 Anode plate 11 Electrode plate width 12 Electrode plate interval 13 Electrode plate thickness 32 Rubber gasket 45 Reinforcement

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-10-87381 (JP, A) JP-A-4-173991 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C25B 1/00-15/08

Claims (3)

(57) [Claims] 1. A diaphragm in which a plurality of anode and cathode electrode plates are arranged in parallel and alternately, and seawater flows between electrodes of an electrolytic cell in which voltages applied to the anode and cathode electrode plates are always in phase. In the electrolysis apparatus, the width of the electrode plate is 50 mm or more and 2
A diaphragmless electrolysis apparatus, wherein the electrode plate interval is not more than 00 mm and the electrode plate interval is not less than 3 times and not more than 5 times the electrode plate thickness. 2. A rubber gasket according to claim 1, wherein a rubber gasket is sandwiched between the anode and cathode electrode plates, and the rubber gasket has a reinforcing member inside. Diaphragm electrolyzer. 3. A rubber gasket for use in a diaphragm-free electrolytic device according to claim 1, further comprising a reinforcing member inside.