JP2003285063A - Water treatment equipment for cooling water system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To supply an electrolytically treated water containing a chlorine-based oxidizing agent generated by electrolytically treating a cooling water to a cooling water system, thereby preventing generation of slime in the system. In the water treatment method and apparatus, deterioration and damage of piping and equipment due to abnormal heat generation of the electrode unit are prevented, and operation is continued safely for a long period of time. SOLUTION: A current is supplied to electrodes 4A and 4B immersed in cooling water, and a water treatment method of a cooling water system in which electrolytically treated water in which a chlorine-based oxidizing agent is generated from chloride ions contained in the water is contained in the cooling water system. In the apparatus, the cylindrical casing 4 is disposed in the cooling tower 1 and the lower end of the casing 4 is disposed in the cooling water. Water level W in the cooling tower 1 in the casing 4
The electrodes 4A and 4B are arranged above L. Pump P ₂
The cooling water is injected into the casing 4, it is applied only electrodes 4A during operation of the pump P _2, the voltage to 4B.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooling water-based water treatment method, and more specifically, to electrolytically process cooling water to produce a chlorine-based oxidizer such as hypochlorous acid from chloride ions in the cooling water. The present invention relates to a cooling water system water treatment method for preventing a slime problem of a cooling water system by this chlorine-based oxidizing agent.

[0002]

2. Description of the Related Art In a cooling water system, slimes are easily generated by microorganisms. In particular, in highly concentrated operation of the circulating cooling water system, the water quality of the cooling water is deteriorated, and slime, which is formed by mixing earth and sand and dust with microbial groups such as bacteria, mold, algae, etc., easily occurs, and the heat exchanger Cause deterioration of heat efficiency and deterioration of water flow. It also induces local corrosion of equipment and piping at the slime adhesion part.

In order to prevent such damage caused by slime, a chlorine-based agent or a non-chlorine-based microbial repellent is added to the circulating cooling water as a slime control agent. Also, as a method for preventing slime without adding such chemicals, chloride ions contained in cooling water are converted to chlorine-based oxidizers such as hypochlorous acid by electrolytic oxidation, and this chlorine-based oxidation is performed. The method of making an agent exist in cooling water is also performed.

[0004] That is, the tap water or industrial water used as make-up water for the cooling water system, usually several ^mg-Cl - / ^L~10
Since chloride ions of about mg-Cl ⁻ / L are contained, the chloride water in the makeup water is concentrated in the cooling water of the circulating cooling water system by the highly concentrated operation of 6 to 8 times. . Therefore, by electrolytically treating this cooling water,
Residual chlorine (free chlorine) having a slime preventing effect can be generated from chloride ions in cooling water. By returning the electrolytically treated water containing this residual chlorine to the cooling water system,
Slime disorders can be prevented.

In the electrolytic treatment apparatus for generating the chlorine-based oxidizing agent, a DC voltage is applied between the anode and the cathode by using an external power source, and cooling water is passed between both electrodes.
As a result, chloride ions in the cooling water are oxidized on the surface of the anode, and residual chlorine having a strong oxidizing power such as hypochlorous acid is generated. The generated residual chlorine sterilizes the microorganisms that cause slime or suppresses the growth thereof, so that the generation of slime in the circulating cooling water system can be effectively prevented.

[0006]

When electrolytically treating cooling water, a failure of a pump for supplying the cooling water to the electrolytic treatment device,
Alternatively, if the cooling water stops flowing to the electrolytic treatment device for some reason, such as the blockage of this supply pipe, the cooling water accumulated between the electrodes will generate heat, and the pipes around the electrodes and other equipment will be overheated. It may deteriorate or be damaged. In particular, a member made of a material having low heat resistance is greatly damaged.

According to the present invention, there is provided a cooling water system water treatment apparatus for electrolytically treating cooling water to supply electrolytically treated water containing a chlorine-based oxidizer to the cooling water system to prevent slime in the system. The purpose of the present invention is to prevent the deterioration and damage of the piping and equipment due to the abnormal heat generation of the electrode part and to continue the safe operation for a long time.

[0008]

The cooling water-based water treatment apparatus of the present invention is an electrolytic treatment in which an electrode in contact with cooling water is energized to generate a chlorine-based oxidizer from chloride ions contained in the water. In a water treatment device of a cooling water system in which water is contained in cooling water of a cooling water system, the electrode is arranged above the water surface level in the cooling tower, surrounds the electrode, and below the lower end of the electrode. It is characterized in that a casing having a water outflow portion and a pump for supplying water in the cooling tower are provided in the casing.

In the present invention, the water in the cooling tower is introduced into the casing by the pump, and the electrodes come into contact with the cooling water.
By applying a voltage between the electrodes, an electric current flows between the electrodes when the cooling water comes into contact with the cooling water to generate a chlorine-based oxidant.

In this case, it is preferable to provide control means for energizing the electrodes only when the pump is operating. This allows
The electrodes are prevented from being energized when the pump is not operating.

Even if this control means is provided, the electrodes are energized when the pump fails or the piping is clogged. However, in the present invention, if water is not supplied into the casing, the electrodes do not come into contact with water, so that even if a voltage is applied to the electrodes, no current flows between the electrodes and no overheating occurs.

In the present invention, the electrode and the casing are arranged in the cooling tower, and the casing is a cylindrical body having a cylinder axis direction as a vertical direction, and the lower end of the cylindrical body is inside the cooling tower. It is preferably arranged below the water surface. This structure has a simple structure and is excellent in durability. This tubular body is preferably made of a synthetic resin that is not deteriorated by a chlorine-based oxidizing agent.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a cooling water system water treatment method of the present invention will be described in detail below with reference to the drawings.

FIG. 1 (a) is a system diagram showing an embodiment of a cooling water system water treatment apparatus of the present invention, and FIG.

A sprinkler plate 1A is provided above the cooling tower 1,
There is a water storage pit at the bottom. The cooling water in the pit of the cooling tower 1 is sent to the heat exchanger 2 via the pipe 11 by the pump P ₁ , and the return water is returned to the cooling tower 1 via the pipe 12 and sprayed from the water spray plate 1A. It

An electrolytic treatment device 3 is provided in the cooling tower 1. This electrolytic treatment device 3 includes a casing 4 made of a tubular body and an electrode 4 provided in the casing 4.
A, 4B, a power supply (not shown) for applying a voltage to the electrodes 4A, 4B, and a pump (in this embodiment, a submersible pump) for injecting water in the cooling tower 1 into the casing P ₂
It has and.

The casing 4 made of a tubular body has a cylindrical shape or a rectangular tube shape made of a synthetic resin such as vinyl chloride, and the top and bottom surfaces thereof are open. The casing 4 is supported by the support member 14 in a suspended state on the cooling tower 1. The lower end of the casing 4 is located below the water level WL of the cooling water in the cooling tower 1 and above the bottom surface of the cooling tower 1. This casing 4
The opening at the bottom of the is the water outlet.

One end of the pipe 13 is connected to the discharge port of the pump P ₂ , and the other end faces the inside of the casing 4 downward from above the casing 4.

The pump P ₂ is also operated when the electrodes 4A and 4B are energized, and is stopped at the same time when the electrodes 4A and 4B are deenergized.

When the cooling water system operates, the pumps P ₁ and P ₂ operate and a voltage is applied between the electrodes 4A and 4B.

As the pump P ₂ is started, the water in the cooling tower 1 is injected into the casing 4, the casing 4 is filled with water or almost filled with water, the electrodes 4A and 4B are submerged, and the space between the electrodes 4A and 4B is increased. An electric current flows. Thereby, water is electrolyzed and a chlorine-based oxidant is generated. The water containing the chlorine-based oxidant flows out from the bottom of the casing 4 and returns into the cooling tower 1. The water in the cooling tower 1 is, as described above, pump P
It is circulated and supplied to the heat exchanger 2 by ₁ . The amount of water discharged from the pump P ₂ is such that the inside of the casing 4 is full or almost full. Preferably, when the pump P ₂ operates, the inside of the casing 4 is filled with water, and excess water overflows from the casing 4.

When the pump P ₂ is stopped, the electrodes 4A, 4B
The voltage application between the two is also stopped.

According to this embodiment, since the voltage is applied between the electrodes 4A and 4B only when the pump P ₂ is operating, water does not stay between the electrodes and generate heat. Moreover, since water is not supplied into the casing 4 when the pump P ₂ fails or the pipe 13 is clogged,
No current flows between the electrodes 4A and 4B, and overheating is reliably prevented.

1 (a) and 1 (b), since the casing 4 is arranged in the cooling tower, the cooling tower is not bulky, the structure is simple, and the cooling tower and its peripheral equipment can be easily installed.

However, in the present invention, the casing 40 may be installed outside the cooling tower 1 as shown in FIG. 1 (c). In FIG. 1C, the casing 40 is composed of a tank, and the lower portion and the upper portion of the casing 40 are connected to the cooling tower 1 by a discharge pipe 41 and an overflow pipe 42, respectively. The water in the cooling tower 1 is poured into the casing 40 by the pump P ₂ and the pipe 13.

The electrodes 4A and 4B in the casing 40 are installed so that their lower ends are higher than the water level WL in the cooling tower 1. Also in this embodiment, the voltage is applied between the electrodes 4A and 4B only when the pump P ₂ operates.

Also in this embodiment, even if the pump P ₂ fails or the pipe 13 is clogged, overheating is reliably prevented.

[0028]

As described above in detail, according to the present invention, electrolytically treated water containing a chlorine-based oxidizer produced by electrolytically treating cooling water is supplied to the cooling water system, whereby slime in the system is provided. In a water treatment method and water treatment device for a cooling water system that prevents the occurrence of
It is possible to reliably prevent deterioration or damage of piping and equipment due to overheating. Therefore, the safe operation of the electrolytic treatment apparatus can be continuously performed, and the slime trouble of the cooling water system can be prevented for a long period of time by stably supplying the chlorine-based oxidant to the cooling water system.

[Brief description of drawings]

FIG. 1 (a) is a system diagram showing an embodiment of a cooling water system water treatment device of the present invention, FIG. 1 (b) is a sectional view showing an enlarged main part of FIG. 1 (a), and FIG. FIG. 3 is a cross-sectional view of main parts of the embodiment of FIG.

[Explanation of symbols]

1 cooling tower 1A water spray plate 2 heat exchanger 3 Electrolytic treatment equipment 4,40 casing 4A, 4B electrodes

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Claims (4)

[Claims] 1. A water treatment of a cooling water system in which cooling water of a cooling water system contains electrolytically treated water in which a chlorine-based oxidizing agent is generated from chloride ions contained in the water by energizing an electrode in contact with the cooling water. In the apparatus, the electrode is arranged above the water level in the cooling tower, and the casing surrounds the electrode and has a water outlet portion below the lower end of the electrode, and a cooling inside the casing. A cooling water system water treatment device, which is provided with a pump for supplying water in the tower. 2. The electrode and the casing are arranged in the cooling tower according to claim 1, wherein the casing is a tubular body whose cylinder axis direction is a vertical direction, and a lower end of the tubular body is A water treatment device for a cooling water system, which is arranged below the water level in the cooling tower. 3. The cooling water system water treatment device according to claim 2, wherein the cylindrical body is made of synthetic resin. 4. The water treatment apparatus for a cooling water system according to claim 1, further comprising control means for energizing the electrodes only when the pump is in operation.