JP2971511B2 - Electrochemical treatment method for water to be treated - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention is intended to electrochemically remove metal ions such as calcium, magnesium or silicon dissolved in water to be treated such as cooling water for a heat exchanger. More specifically, by supplying the water to be treated to a three-dimensional electrode type electrolytic cell and electrochemically treating the same, the metal ions such as calcium are converted into hydroxides or oxides of the three-dimensional electrode. The present invention relates to a method for electrochemically treating water to be precipitated and removed therefrom.

(Prior Art) In recent years, as the number of buildings formed by a large number of companies, such as condominiums and other apartments or buildings, has increased in recent years, the number of various types of cooling and heating equipment installed in the buildings and the like has increased dramatically. Has increased. In an apartment or the like in which such a large number of cooling and heating facilities are installed, equipment for heat exchangers for cooling water of the cooling and heating equipment, for example, a tank for a heat exchanger is usually installed on the roof. If this cooling water is used for a long period of time, bacteria and fungi will proliferate, and the calcium and magnesium ion concentrations of the heat exchange water will gradually increase due to the operation of replenishing the reduced amount of water due to evaporation.

When the concentration of calcium and / or magnesium ions in the cooling water for the heat exchanger increases, the ions are deposited on the heat exchange surface of the heat exchanger to greatly reduce the heat exchange efficiency, or to reduce the cooling water circulation pipe. In the worst case, the metal hydroxide precipitates on the inner wall surface, and the pipe is closed, so that the cooling water cannot be circulated.

In addition, natural water often contains hard water in which a large amount of calcium and magnesium salts are dissolved. When drinking water is prepared from this hard water, calcium and magnesium are also dissolved in drinking water. Adverse effects such as worsening the image quality.

In order to remove these calcium salts and magnesium salts from cooling water and drinking water, treatments such as boiling treatment and ion exchange treatment are conventionally performed, but these treatments are particularly necessary when a large amount of treatment is required. It is costly and not commercially available. Therefore, conventionally, the inside of the pipe is washed before the pipe is closed, or the drinking water having a reduced taste is drunk as it is.

(Problems to be Solved by the Invention) As described above, various ions or salts such as calcium and magnesium contained in various kinds of water to be treated including cooling water for a heat exchanger and drinking water can be relatively easily and in large quantities. Conventionally, there is no means that can be removed from the water to be treated, and the disadvantage caused by the presence of the ions and the like is directly accepted.

(Object of the Invention) The present invention makes it possible to easily remove the ions from the water to be treated containing ions or salts such as calcium and magnesium, such as cooling water for a heat exchanger, without using a chemical or requiring a complicated operation. It is an object of the present invention to provide a method that can be removed.

(Means for Solving the Problems) The present invention has a three-dimensional electrode in which water to be treated containing ions of one or more metals selected from calcium, magnesium and silicon is polarized by applying a voltage. 1 or 2 selected from the calcium, magnesium and silicon in the water to be treated, supplied to a three-dimensional electrode type electrolytic cell
This is an electrochemical treatment method for the water to be treated, in which the metal ions are converted into their hydroxides or oxides, deposited on the three-dimensional electrode, and removed from the water to be treated. In the present invention, a tank used in the present invention should be called an electrochemical treatment tank because a substantial electrochemical reaction may not occur on the surface of an electrode or the like, but is called an electrolytic tank according to a general name.

 Hereinafter, the present invention will be described in detail.

The present invention supplies water to be treated containing ions such as calcium and magnesium such as cooling water for a heat exchanger to a three-dimensional electrode type electrolytic cell, and applies a DC or AC voltage to the electrolytic cell to accompany a gas by electrolysis. Alternatively, the water to be treated is treated without the treatment to remove the calcium and magnesium from the water to be treated.

Tap water contains calcium ions and magnesium ions, and the clogging of the pipe due to the precipitation of these ions on the inner wall of the pipe of the tap water is a major problem.However, in many cases, heat exchange using tap water as a water source Calcium ion and magnesium ion are also contained in dexterous cooling water,
If the ions easily adhere to the heat exchange surface of the heat exchanger, they lower the heat exchange efficiency between the cooling water and the water to be cooled. Calcium ions and magnesium ions in the heat exchanger cooling water that degrade the performance of the heat exchanger as described above, when the cooling water is subjected to electrochemical treatment, is formed on the cathode or the three-dimensional electrode of the three-dimensional electrode type electrolytic cell. It is reduced to precipitate on the cathode surface as calcium hydroxide or magnesium hydroxide and is removed from the cooling water, and does not precipitate on the heat exchange surface to lower the heat exchange efficiency. In addition, silicon ions and salts other than calcium and magnesium may be dissolved in tap water,
Although the presence of the silicon ions is not preferred, when the water to be treated in which the silicon ions are dissolved is subjected to the electrochemical treatment according to the present invention, the silicon ions are converted into silicon oxide and deposited on the cathode, and the water to be treated is removed. Removed from

The electrolytic cell used in the method of the present invention is a bipolar fixed-bed type three-dimensional electrode electrolytic cell. In the treatment of the water to be treated such as cooling water for a heat exchanger according to the present invention, the treatment efficiency increases as the treatment water to be treated has more chances to come into contact with electrodes or dielectrics or particles described later, and the efficiency is increased. Calcium ions and the like are removed. Therefore, using a bipolar fixed-bed three-dimensional electrode electrolytic cell having a large surface area such as an electrode can increase the processing efficiency as compared with the case of using other electrolytic cells, thereby achieving the same processing efficiency. This is advantageous in that the required device size can be made smaller than other electrolytic cells.

The three-dimensional electrode in the three-dimensional electrode electrolytic cell of the present invention has a porous material through which the water to be treated can be permeable, for example, granular, spherical, felt, woven, porous block, and a large number of through holes. Activated carbon having a shape such as solid, graphite, carbon-based materials such as carbon fibers, or metal materials such as nickel, copper, stainless steel, iron, titanium, etc. having the same shape, and a precious metal coating applied to these metal materials It is preferable that the three-dimensional electrode is made of a plurality of dielectrics formed of a material, and the three-dimensional electrode is placed in a DC electric field, and is made of a perforated plate such as a flat plate, an expanded mesh, or a perforated plate disposed at both ends. A DC voltage is applied between the power supply positive and negative electrodes to polarize the dielectric, and positive and negative charges are formed at one end and the other end of the dielectric, respectively, so that the dielectric is polarized. In addition to this, a three-dimensional material functioning independently as an anode or a cathode is installed separately from the power supply anode and cathode so as not to be alternately short-circuited and electrically connected to form a bipolar fixed-bed electrolytic cell. can do. When the solid body having a large number of through holes described above is used as a three-dimensional electrode, the opening ratio is set to 10% or more and 95% or less, preferably 20% so as not to hinder the movement of the flowing cooling water.
It is preferable that the opening diameter of the through-holes is not less than 80%, and the opening diameter of the through-holes is a fine hole having such a diameter that the liquid to be treated can pass through.

When a carbon-based material such as activated carbon, graphite, or carbon fiber is used as the dielectric and water to be treated is treated while generating oxygen gas from the anode, the dielectric is oxidized by oxygen gas and dissolved as carbon dioxide. Easier to do. In order to prevent this, a porous material which is usually used as an insoluble metal electrode by coating a platinum group metal oxide such as iridium oxide or ruthenium oxide on a base material such as titanium on the side where the dielectric material is positively polarized is used. What is necessary is just to install in a contact state, and to generate | occur | produce oxygen mainly on this porous material.

When an anode and a cathode other than the dielectric or power supply positive and negative electrodes are brought close to each other to lower the voltage, for example, a mesh spacer made of an organic polymer material or the like is inserted as an electrically insulating spacer to prevent a short circuit. Is preferred.

Since the liquid to be treated has a relatively large gap in the electrolytic cell through which the liquid to be treated flows without contacting the dielectric or the anode or the cathode, the treatment efficiency of the liquid to be treated decreases, It is desirable that the dielectric and the like be arranged so that the flow of the liquid to be treated in the electrolytic cell does not short-path.

When the water to be treated supplied to the three-dimensional electrode type electrolytic cell is laminar, the liquid movement in the lateral direction is small and the water to be treated passes through the electrolytic cell without sufficiently contacting the surface of the dielectric or the like. Sometimes. In particular, calcium ions and the like contained in the water to be treated are converted into hydroxides and oxides and do not deposit on the electrodes unless they come into contact with the electrode surface. Therefore, the water to be treated is a turbulent flow having a Reynolds number of 500 or more so that calcium ions and the like in the liquid to be treated sufficiently contact the electrode surface, and the electrolytic cell is moved while sufficiently moving in the lateral direction. It is desirable to let it pass. The Reynolds number is
(Fluid velocity) × (inner diameter of flow path) の (kinetic viscosity coefficient of fluid), and the larger this value, the greater the degree of turbulence of the fluid.

In the present invention, the value of the DC voltage applied between the positive and negative electrodes is not particularly limited as long as a sufficient amount of current is supplied to convert the calcium ions and the like to the corresponding hydroxides and oxides. If the amount of converted calcium ions or the like is small and a slight potential is generated on the electrode surface, the treatment is performed. Accordingly, the method of the present invention may be either an electrolytic treatment in which a current flows and gas is generated on the electrode surface, or a process in which no current flows and no gas is generated on the electrode surface. In order to confirm that the treatment is being performed efficiently, it is desirable to apply an electric current and perform the electrolytic treatment while generating a small amount of gas. The preferred anode potential is +0.2 to +1.4 V (vs. SHE) and the preferred cathode potential is nobler than -1.2 V (vs. SHE). Chemical treatment can be performed.

The gas generated by water electrolysis, that is, oxygen gas and hydrogen gas, is usually generated at a mixing ratio within the explosion limit, so if a relatively large DC voltage is applied to generate gas, use air or other gas to avoid the danger of explosion. For example, means for separating the electrolytic gas generated at the outlet of the electrolytic cell and means for diluting the electrolytic gas after separation with air so that the electrolytic gas concentration becomes 4% by volume or less. However, since the capacity of the electrolytic cell for treating the cooling water for the heat exchanger and the like is relatively small and the amount of generated gas is small, the gas separation means may not be provided.

The three-dimensional electrode electrolytic cell having such a configuration is installed close to a place where the treatment of the water to be treated is required in accordance with the type of the liquid to be treated, particularly in the case of cooling water for a heat exchanger. Is installed in the vicinity of a heat exchanger installed on the roof of a building or condominium, and after circulating part of the cooling water in the heat exchanger to remove calcium ions and the like in the electrolytic cell, It can be used by returning it to the heat exchanger.

Further, in the electrolytic cell of the present invention, a leakage current is generated in the electrolytic cell, and the leakage current flows from the electrolytic cell through the water to be treated into another metal member, for example, a heat exchanger, and is electrolyzed into the member by elution or the like. Corrosion may occur. For this reason, the power supply positive and negative electrodes in the electrolytic cell are not opposed to each other, and
Alternatively, a member having higher conductivity than the water to be treated can be installed in the inlet / outlet pipe of the electrolytic cell so that one end thereof can be grounded, and the leakage current can be cut off.

In addition, solid impurities may be mixed into the cooling water for the heat exchanger while flowing through the piping, and before and after, preferably before, the heat exchanger to remove the impurities in addition to the above-described electrochemical treatment. It is desirable to install a filter.

The cooling water for the heat exchanger has an appropriate temperature and is in an environment where microorganisms such as molds and bacteria can easily propagate, and other water to be treated may also contain microorganisms.

When a DC voltage is applied to water to be treated such as cooling water for a heat exchanger according to the present invention, not only calcium ions and the like in the water to be treated are removed, but also the water to be treated in the water to be treated is It is considered that the liquid flows contact the three-dimensional electrodes of the three-dimensional electrode type electrolysis tank and undergo a strong oxidation-reduction reaction on their surface to weaken their sliding or die themselves. Therefore, according to the method of the present invention, not only the removal of calcium ions and the like, but also the sterilization or fungicide of the water to be treated can be performed simultaneously.

Next, preferred examples of the electrolytic cell that can be used in the present invention will be described with reference to the accompanying drawings. However, the electrolytic cell used in the method of the present invention is not limited to this electrolytic cell.

FIG. 1 is a schematic longitudinal sectional view showing an example of a bipolar fixed-bed type electrolytic cell that can be used as the electrolytic cell of the present invention, and FIG. 2 is a diagram in which the electrolytic cell of FIG. 1 is installed in front of a heat exchanger. It is the schematic which shows the state which performed.

A mesh-like power supply electrode 3 and a power supply cathode 4 are provided near the upper end and the lower end of a cylindrical electrolytic cell main body 2 having a flange 1 at the top and bottom, respectively. The electrolytic cell main body 2 is preferably formed of an electric insulating material that can withstand long-term use or re-use. In particular, synthetic resins such as polyepichlorohydrin, polyvinyl methacrylate,
Polyethylene, polypropylene, polyvinyl chloride, polyvinyl chloride, phenol-formaldehyde resin and the like can be preferably used. The power supply anode 3 for applying a positive DC voltage includes, for example, a carbon material (eg, activated carbon, charcoal, coke, coal, etc.), a graphite material (eg, carbon fiber, carbon cloth, graphite, etc.), a carbon composite material (eg, carbon to metal Activated carbon fiber non-woven fabric (for example, KE-1000 felt, Toyobo Co., Ltd.),
Alternatively, it is formed of a material having platinum, platinum, palladium or nickel supported thereon, a dimensionally stable electrode (a platinum group oxide-coated titanium material), a platinum-coated titanium material, a nickel material, a stainless steel material, an iron material, or the like. The power supply cathode 4 which faces the power supply anode 3 and applies a negative DC voltage is made of, for example, platinum, stainless steel, titanium, nickel, Hastelloy, graphite, carbon material, mild steel, or a metal material coated with a platinum group metal. ing.

A plurality of, in the example shown, three fixed beds 5 are laminated between the two power feeding electrodes 3 and 4, and between the fixed floor 5 and between the fixed floor 5 and the two power feeding electrodes 3 and 4. Are sandwiched between four porous diaphragms or spacers 6. Each fixed floor 5
Are arranged so as to be in close contact with the inner wall of the electrolytic cell main body 2, do not pass through the inside of the fixed bed 5, and minimize the leakage flow of the cooling liquid flowing between the fixed bed 5 and the side wall of the electrolytic cell main body 2. . When a diaphragm is used, a woven fabric, a calcined plate, a particle sintered plastic, a perforated plate, an ion exchange membrane, or the like is used as the diaphragm, and a woven fabric, a perforated plate, a net, made of an electrically insulating material as a spacer. A rod-shaped material or the like is used.

As shown in FIG. 2, the electrolytic cell 2 having such a configuration is used as a heat exchanger 12 on the roof of a building 11 such as a building or an apartment.
It is installed together with the filter 13 in close proximity to. The building
A predetermined cooling and heating device is installed on each floor of 11, and the cooling water for the heat exchanger cooled by contacting the fins 14 of the heat exchanger 12 is supplied to the cooling and heating equipment through a cooling water supply pipe 15 and is supplied to the equipment. After cooling the circulating water to be used, the water is circulated on the roof through a cooling water recovery pipe 17 by a pump 16 and solid impurities are removed through a filter 13 and then supplied to the electrolytic cell 2.

When energization is performed while supplying the cooling water supplied to the electrolytic cell from below as shown by the arrow in FIG. 1, each fixed bed 5 is fixed with the lower surface polarized positively and the upper surface negatively polarized as shown in the figure. Floor 5
A potential is generated between the inside and the fixed bed 5, and the cooling water flowing in the electrolytic cell causes the fixed bed 5 polarized positively or negatively by this potential.
And then subjected to a modification treatment such as disinfection of mold and bacteria in the cooling water and precipitation removal of calcium and magnesium ions as hydroxides, taken out from the upper part of the electrolytic cell 2, and shown in FIG. As shown, the heat is circulated through the heat exchanger, and the treatment of the heat exchanger cooling water is similarly continued.

FIG. 3 shows another example of a bipolar-type fixed-bed electrolytic cell which can be used in the present invention. The electrolytic cell is a side of the fixed bed 5 of the electrolytic cell shown in FIG. The mesh-shaped insoluble metal material 7 is installed in a state of close contact on the side to be positively polarized, and the other members are the same as those in FIG.

When gas generation accompanies the fixed bed 5 to which a DC or AC voltage is applied, the positively polarized side of the fixed bed 5 where oxygen gas is generated is worn and deteriorated. As shown, the insoluble metal material 7
Is installed, since the overvoltage of the insoluble metal material 7 is lower than the overvoltage of the carbon-based material forming the fixed bed 5, most of the oxygen gas is generated from the insoluble metal material 7, and the fixed bed 5 is almost free of oxygen gas. Since there is no contact, the dissolution of the fixed bed 5 is effectively suppressed. The cooling water for the heat exchanger supplied to the electrolytic cell 2 is treated in the same manner as in FIGS. 1 and 2, and a treatment such as calcium removal is performed.

FIG. 4 shows another example of a bipolar-type fixed-bed electrolytic cell that can be used in the present invention.

A mesh-shaped power supply anode 23 and a power supply cathode 24 are provided near the upper end and the lower end of a cylindrical electrolytic cell main body 22 having upper and lower flanges 21, respectively. Electrolyzer body
22 is preferably formed of an electrical insulating material that can withstand long-term use or re-use, especially a synthetic resin.

Between the power supply electrodes 23 and 24, a large number of fixed bed forming particles 25 formed of a conductive material such as a carbon-based material, and a smaller number of the fixed bed forming particles 25, such as synthetic resin insulating particles 28, are used. Are almost uniformly mixed. The insulating particles 28 have a function of preventing the power supply anode 23 and the power supply cathode 24 from being completely short-circuited.

When electricity is supplied to the electrolytic cell having such a configuration while supplying cooling water for a heat exchanger as indicated by an arrow from below,
Each of the fixed bed forming particles 25 functions as a three-dimensional electrode having an enormous surface area by polarizing the power supply anode 23 side negatively and the power supply cathode 24 side positively, similar to the electrolytic cell of FIG. 1 and FIG. Then, the cooling water is subjected to a reforming treatment such as sterilization of microorganisms and removal of calcium ions and magnesium ions, and is taken out from above the electrolytic cell.

(Example) Hereinafter, an example of a cooling water reforming treatment for a heat exchanger according to the method of the present invention will be described, but the example does not limit the present invention.

Example 1 Transparent rigid polyvinyl chloride resin, height 400 mm, inner diameter 6
The electrolytic cell shown in FIG. 1 having a 00 mm cylindrical shape with a flange was installed between the cooling tower filter equipment as shown in FIG. The diameter of the electrolytic cell is made of carbon fiber.
15 fixed floors with a thickness of 600mm and a thickness of 10mm are created with an aperture ratio of 80% and a diameter of 600
A mesh-shaped power supply anode and a power supply cathode with a diameter of 580 mm and a thickness of 1.0 mm, which are made of titanium in which platinum is plated on the surfaces of upper and lower ends, respectively, sandwiched between 16 polyethylene resin membranes having a thickness of 1.2 mm and a thickness of 1.2 mm. It was installed in contact.

The cooling water for the heat exchanger was supplied to the electrolytic cell at a speed of 10 tons /, and the electrolytic voltage shown in Table 1 was applied between the power supplying electrodes to perform the treatment of the cooling water. Table 1 summarizes the presence or absence of generated gas by visual observation, the concentrations of calcium and magnesium ions in the cooling water before and after passing through the electrolytic cell, the number of bacteria, and the amount of power consumption in the treatment operation.

From Table 1, it can be seen that the calcium and magnesium ion concentration and the number of bacteria are significantly reduced by treating the cooling water for the heat exchanger in the electrolytic cell.

After 30 days, the power supply was stopped, the electrolytic cell was disassembled, and the state of the fixed bed was observed. No change was observed.

Example 2 Using the electrolytic cell body of Example 1 and a positive electrode for power supply, graphite particles having a particle size of 5 to 10 mm and insulating particles made of hard polyvinyl chloride resin and having a particle size of 5 to 10 mm were provided between the power supply electrodes. Was mixed at a weight ratio of 4: 1 to form an electrolytic cell shown in FIG.

This electrolytic cell was placed close to the cooling tower in the same manner as in Example 1, the cooling water for the heat exchanger cooling tower was treated under the same conditions, the presence or absence of generated gas by visual observation in the treatment operation, before and after passing through the electrolytic cell. Table 2 summarizes the results of the calcium and magnesium ion concentrations, the number of bacteria, and the power consumption of the cooling water.

Table 2 shows that the concentrations of calcium and magnesium ions and the number of bacteria in the cooling water for the heat exchanger are significantly reduced by the treatment in the electrolytic cell.

Example 3 Using the electrolytic cell of Example 1, the effect of the supplied cooling water for the heat exchanger on the sterilization rate and the removal rate of calcium and magnesium ions was examined by changing the Reynolds number. The results are shown in Table 3. The number of bacteria at the inlet of the cooling water electrolytic cell was 413,000 / calcium, and the total amount of calcium and magnesium ions was 33 ppm.

From Table 3, if the Reynolds number is less than 500 The sterilization rate “[(number of bacteria in the inlet) − (number of bacteria in the outlet)] ÷ (number of bacteria in the inlet) × 100” is insufficient, and considerable bacteria remain in the treated water discharged from the outlet of the electrolytic cell. It can be seen that when the Reynolds number becomes 500 or more, almost completely sterilized water to be treated is taken out of the electrolytic cell. Calcium and magnesium ion concentration of the water to be treated is 33ppm to 10p
It can be seen that it decreases to less than pm.

(Effect of the Invention) In the method of the present invention, water to be treated containing ions such as calcium, magnesium and silicon is supplied to a three-dimensional electrode type electrolytic cell, and is selected from the calcium, magnesium and silicon in the water to be treated. This is a method for electrochemically treating water to be treated, wherein one or more ions are converted to a hydroxide or oxide thereof, deposited on the three-dimensional electrode, and removed from the water to be treated (claim 1).

Blockage of the pipe due to precipitation of hydroxide or the like on the inner wall of the pipe such as calcium ions or magnesium ions contained in tap water is a major problem, but according to the method of the present invention, the treatment containing the calcium ion When water is supplied to a polarized three-dimensional electrode type electrolytic cell having an enormous surface area, the ions are reduced on the polarized three-dimensional electrode and deposited on the cathode surface as calcium hydroxide or magnesium hydroxide to be treated. It is removed from the water cooling water, and at the same time, the microorganisms contained in the water to be treated are sterilized.

As described above, the method of the present invention uses a three-dimensional electrode having an enormous surface area to achieve excellent ion removal efficiency, and a large amount of water to be treated by a relatively simple operation of supplying the water to the electrolytic cell. Can be processed.

The method of the present invention is particularly effective when the water to be treated is cooling water for a heat exchanger (Claim 2), and calcium ions, magnesium ions or silicon ions precipitate as hydroxides or oxides on the heat exchange surface. The heat exchange efficiency is not reduced, and the pipes of the heat exchanger are not blocked.

The water to be treated is placed in a three-dimensional electrode type electrolytic cell with a Reynolds number of 50.
When the water to be treated is supplied so as to be 0 or more (claim 3), the water to be treated moves sufficiently in the lateral direction and sufficiently contacts the three-dimensional electrode to efficiently perform the electrochemical treatment of the water to be treated. You can do it.

Furthermore, the electrolytic gas generated by the method of the present invention becomes a mixed gas of oxygen gas and hydrogen gas within the explosion limit, and there is a danger of explosion if the treatment is performed in a closed system. Therefore, by providing a means for separating gas generated by electrolysis and a means for diluting the separated gas near the outlet of the electrolytic cell, the danger of explosion can be avoided (claim 4).

Furthermore, in the electrolytic cell of the present invention, a leakage current occurs in the electrolytic cell, and the leakage current flows into another metal member such as a heat exchanger,
Electrochemical corrosion such as elution may occur on the member. In order to prevent this, it is preferable to cut off the leakage current by installing a member having higher conductivity than the water to be treated so that one end thereof can be grounded at an appropriate place where the positive cathode for power supply does not face ( Claim 4).

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing an example of a bipolar fixed-bed type electrolytic cell usable as an electrolytic cell in the method of the present invention, and FIG.
FIG. 3 is a schematic view showing the installation state of the electrolytic cell in the figure, FIG. 3 is a longitudinal sectional view showing an example of another bipolar-type fixed-bed electrolytic cell, and FIG.
It is a longitudinal cross-sectional view which shows an example of another bipolar type fixed bed type electrolytic cell. 1, 21 flange, 2, 22 electrolytic cell body 3, 23 anode for power supply, 4, 24 cathode for power supply 5, fixed floor, 6 spacer 7, insoluble metal material 11 … Buildings, 12… Heat exchangers 13… Filters, 14… Fins 15… Cooling water supply pipes, 16… Pumps 17… Cooling water recovery pipes 25 …… Fixed bed forming particles, 28 …… insulating particles

Claims (5)

(57) [Claims] 1. A treatment water containing ions of one or more metals selected from calcium, magnesium and silicon is supplied to a three-dimensional electrode type electrolytic cell having a three-dimensional electrode polarized by application of a voltage. 1 or 2 selected from the calcium, magnesium and silicon in the water to be treated
An electrochemical treatment method for the water to be treated, wherein the metal ions are converted into their hydroxides or oxides, deposited on the three-dimensional electrode, and removed from the water to be treated. 2. The method according to claim 1, wherein the water to be treated is cooling water for a heat exchanger. 3. The method according to claim 1, wherein the water to be treated is treated while flowing the water to be treated through a three-dimensional electrode type electrolytic cell at a Reynolds number of 500 or more. 4. The method according to claim 1, wherein an electrolytic cell provided with a means for separating gas generated by electrolysis and a means for diluting the separated gas is provided near the outlet. 5. A member having higher conductivity than water to be treated is provided on the back surface of the power supply electrode and / or in the inlet / outlet pipe of the electrolytic cell where the positive electrode for power supply in the three-dimensional electrode type electrolytic cell is not opposed. The method according to any one of claims 1 to 4, wherein the processing is performed by being installed so as to be grounded.