JP4618538B2 - Water scale adhesion prevention method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for preventing the adhesion of water scale to improve the satisfaction of users for improving the supply stability and utilization efficiency of tap water, groundwater, industrial water and the like.

Conventionally, when water is used, great efforts have been made to improve its supply stability and utilization efficiency. In particular, periodic inspection and maintenance is an important point for ensuring stable water quality and water volume.
For example, confirmation of well water pumping power source, raw water tank sensor operation confirmation, raw water pump operation confirmation, filtration device confirmation and maintenance, monitoring of residual chlorine, etc., mainly attention to human sea tactics It was.
Furthermore, many attempts have been made to pursue the water quality extremely like an ultrapure water device in semiconductor manufacturing, and as a result, advanced technology has been formed and put into practical use.

On the other hand, although many proposals such as red rust and red water, which are often found in the fields of domestic and industrial water, scales generated in water supply pipes, prevention of algae generation, removal of malodors and slime, etc. have been reported, they are still practically decisive. It is no exaggeration to say that there is nothing.
That is, as a method for protecting the water distribution pipe from red rust, scale, bacteria generation and slime, there are known methods such as physically replacing the water by blowing, and cleaning the pipe by blowing silica sand, etc. It has the disadvantage that it requires water and needs to be shut off during treatment.

Also, there is a method of forming a protective film in the pipe by chemical injection chemical treatment, and it has a proven track record and high reliability, but it is close to emergency treatment and is not a permanent stabilization measure. Processing is required.
In addition, it is positioned as a specialized construction method in that management is severe, and the running cost is high. Epoxy resin lining has been proposed as a method for improving these defects, but is limited in terms of application in terms of cost.

In view of such a situation, there has been proposed a technique that activates water itself and expects an effective effect for preventing deposition, preventing rust, and removing rust.
For example, a method has been proposed in which water is magnetically treated in a pipe flow path in which a magnet structure is present. (See Patent Documents 1 and 2) Further, combinations with ultrasonic waves, high frequencies, and the like, and multi-stage processing thereof have been proposed. (See Patent Documents 3 and 4)
Also, water activation has been proposed by combining a permanent magnet with a water passage pipe coated with a far-infrared radiation material, but this process requires a large number of permanent magnets. (See Patent Document 5)
However, all of these means are required to be improved in a direction in which the inside of the pipe is complicated and the flow path resistance is increased due to the structure.

In addition, there are a combination of excitation of electrons and atoms by α-ray irradiation and magnetism, a treatment with magnetic ceramics to impart a rust-preventive effect, and a treatment with magnetic ceramics with a composite material. However, the treatment cost is expensive and impractical.
As described above, at present, sufficient measures have not been taken with any of the methods, and more effective solutions are being sought.

        Japanese Utility Model Publication No. 4-29917         JP-A-10-85757         Japanese Patent Application Laid-Open No. 7-241666         JP-A-9-66285         Japanese Patent No. 2622911

  In view of the various situations as described above, the present invention uses materials normally used for water treatment, activates the water in the water distribution pipe, which is inexpensive and obtains a permanent effect, and is a particularly wide problem. It is to provide water treatment technology that can prevent the adhesion of scales without using chemicals.

As a result of earnest research to achieve the above-mentioned object from such a viewpoint, the present inventors have selected the treatment conditions during water filtration, and thus the effects caused by the electrochemical action that occurs during the movement of the water to be treated. Based on this method, the water itself is transformed and the dissolved scale substance is made inactive in water and floated.
As a factor causing an electrochemical change in water, the rubbing force of the filter due to the water to be treated, that is, the filtration flux is greatly affected. As a result of careful examination using filters having different pore structures, which are filter structures of filters made of various materials, the present inventors have found the following conditions.

The electrochemical change of water due to rubbing with the material was considered to be the dominant factor due to the electrical properties (volume resistivity, surface resistivity, dielectric constant, charge decay rate, zeta potential, etc.) of the material in contact with the treated water .
Focusing on the electrical properties of these substances, we examined the composition of the filter material, blocking pore size, etc., and the filtration treatment conditions, and also explored the water activation effect using the scale generation prevention effect as an evaluation index. We predicted that metamorphosis would appear.
By sending the transformed water treated under these conditions into the water distribution pipe, it is surprisingly confirmed that not only the scale does not adhere to the water distribution pipe, but also the scale that has already adhered has the effect of peeling off. The present invention has been reached.

That is, the gist of the present invention is that the main part of the constituent material is a synthetic polymer substance, the blocking pore diameter is at least 0.2 μm or less, or the fractional molecular weight is 1 million or less, and the path during filtration is almost bent. In the method for preventing water scale adhesion , the filter is made of a filtration medium configured to be formed and treated with a filtration flux of 50 L / m 2 / hour or more.

Here, although various materials can be used as the constituent material of the filter material forming the filtration media, the synthetic polymer material employed as the main constituent part has been determined through the following examination.
The filtration media that affect the activation of water, which is a feature of the present invention, is generated by an electrochemical action by rubbing with the filter material constituting the filtration media. For this reason, the influence of the electrical properties (volume specific resistance, surface specific resistance, dielectric constant, charge decay rate, zeta potential, etc.) of the material in contact with the water to be treated is extremely important.

The material constituting the filter is polyethylene, polypropylene, polybutylene terephthalate, polyvinylidene fluoride, polyvinyl chloride, polyfluorinated ethylene, (styrene, divinylbenzenesulfonic acid, phenol, benzyl alcohol, resorcin, carbamide, pyrocatechol, melamine, It is intended for synthetic resin materials such as ion exchange resin type synthetic polymers mainly composed of special monomers such as resorcinic acid and hydroquinone.
For these, hollow fiber membrane filters and synthetic resin fine particle sintered cartridge filters with different porosity, blocking pore diameter or fractional molecular weight (hereinafter collectively referred to as blocking pore diameter), etc., are manufactured. We investigated and confirmed the occurrence of scale when the bundle and filtered water were passed through the water distribution pipe.

It was confirmed that if the material constituting the filter is a synthetic polymer substance, the activation of water with the scale prevention effect as an evaluation index is caused. Next, the filter thickness, the blocking hole diameter and the filtration flux affect each other, but the scale preventing effect is recognized even when the blocking hole diameter is 0.2 μm or less, while the scaling preventing effect is recognized when the blocking hole diameter is 0.3 μm or more. There wasn't.
With respect to the filtration flux, the scale preventing effect was not observed unless the flux was at least 10 L / m 2 / hour, preferably 30 L / m 2 / hour or more at a blocking pore diameter of 0.01 μm.
The upper limit of the flux was confirmed up to 2,000 L / m2 / h, but the filter is likely to clog when the flux is high, so it is determined in relation to water quality data such as turbidity required as treated water It is.

  The form of the filter was basically studied as a hollow fiber membrane filter module and a synthetic resin fine particle sintered cartridge filter. A hollow fiber membrane filter made of thermoplastic crystalline polymer such as polyethylene or polypropylene was produced by a melt drawing method. Polyamide-based, polysulfone-based, polyvinyl chloride-based, acrylic-based, fluorocarbon-based polymers, etc., are based on the wet spinning method in which they are dissolved in each solvent and extruded into a non-solvent as a synthetic resin solution. Produced.

In the case of a hollow fiber membrane, the thickness of the membrane wall is preferably 50 μm to 100 μm for the convenience of production and consideration of physical strength at the time of practical use. 0.05, 0.1, 0.2, 0.3, and 0.5 μm. In addition, the hole area ratio of the hollow fiber membrane was 60 to 75%.
To make a hollow fiber membrane filter module, put the hollow fiber membrane in a cylindrical outer cylinder, impregnate both ends with a two-component urethane resin, cure it, provide raw water inlet and treated water outlet, Modular shape as a mold or an internal pressure mold.
In the case of the hollow fiber membrane filter module, the total outer peripheral membrane area of the hollow fiber membrane was used as a reference in the case of external pressure filtration, and the total inner peripheral area of the hollow fiber membrane was used in the case of internal pressure filtration. In the case of a cartridge filter, since it is an external pressure filtration, the entire outer peripheral area was used as a reference.

  As for the blocking pore diameter of the filter, the “blocking pore diameter” is used at the microfiltration level, and is displayed as “fraction molecular weight” in the ultrafiltration region of 0.01 μm or less. In the present invention, the expression “blocking pore diameter” is unified and described. However, since “blocking pore diameter” of 0.1 μm corresponds to about 1 million daltons in the molecular weight cut-off, both are used together.

In addition, synthetic resin from styrene, divinylbenzene sulfonic acid, or special monomers makes bead-shaped pellets with a diameter of 0.1 mm to 1.0 mm, and is heat-molded with a small amount of solvent in a mold for cartridge filter molding. A synthetic resin fine particle sintered cartridge filter having an outer diameter of 64 mm and a length of 10 inches was manufactured.
The blocking hole diameter of this type of cartridge filter is mainly about 0.03 μm, 0.05 μm, and 1.0 μm, and the wall thickness of the filter is 10 mm.

In the various filters used in the water filtration of the present invention, it is extremely desirable that the water passage water channel connected in the thickness direction of the filtration path, that is, the filter structure is a curved path instead of a straight path.
That is, in water filtration, the thickness of the filter becomes the filtration resistance, and the filtration speed per unit area, that is, has a great influence on the flux. It becomes a necessary condition.

However, in order to cause an electrochemical change in water, the contact time between the water to be treated and the filter must be long. In order to realize the trade-off between the flux and the contact time without increasing the thickness of the filter, the flow path in the filter must be bent. The path length of the bent channel is preferably at least four times that of the channel due to the linear gap .

With the advent of the present invention, inexpensive and permanent scale prevention means can be realized by a simple facility without using chemicals that have not been solved for many years. The present invention originates from the electrochemical water activation effect, and can be applied to various boilers, heat exchangers and their constricted parts, water washing dryers, and the like, and is useful as an innovative scale prevention technology. It is.
That is, at the time of receiving water, the water filtration device specified in the present invention is arranged immediately before landing in the water receiving tank, or a boiler, a heat exchanger, a dishwasher, etc., which are problematic due to the occurrence of scale, etc. This can be achieved by providing a water filtration device specified in the present invention in the water introduction portion to the terminal equipment.

As a result, the water is transformed and activated due to the electrochemical action of water, and the effects such as scale prevention are reliably and continuously realized.
Furthermore, it is effective in preventing slimming and red rust prevention by sterilization, and it is believed that the effect of the present invention is industrially significant.

  Hereinafter, the present invention will be specifically described based on examples.

Using a synthetic resin composed of styrene and divinylbenzene sulfonic acid, a bead-shaped pellet of 0.1 mm to 1.0 mm in diameter is produced. Using this, a small amount of solvent is put into a mold for molding a cartridge filter and heat molded. Several types of synthetic resin fine particle sintered cartridge filters having a diameter of 64 mm and a length of 10 inches were manufactured.
Each cartridge filter has a blocking hole diameter of 0.03 μm. Tests were performed with 0.05 μm, 1.0 μm, 3.0 μm, and 5.0 μm, with the filter wall thickness adjusted to 10 mm.

These were each put into a 10 inch filter cartridge holder and subjected to filtration. These filters were installed in a replenishment water line of a cooling tower using groundwater (amount of replenishment water of 1 m3 / hour), and a test line in which filter treated water was directly fed into the cooling tower was created and tested under various conditions.
The total hardness of the makeup water was 800 mg / L, and a large amount of scale adhered to the fins around 30 days before the installation of the filter of the present invention, but 60 days except for 3.0 μm and 5.0 μm filters. Even after the eyes passed, no problem occurred and the effect of the present invention was confirmed.

Dissolve synthetic resin mainly composed of polyvinyl chloride resin in solvent, extrude the solution into non-solvent using concentric nozzle, adjust solution concentration and non-solvent constituent requirements, solvent / non-solvent system A hollow fiber membrane filter having an outer diameter of 800 μm, an inner diameter of 600 μm, and pore sizes of 0.01 μm (A) and 0.3 μm (B) was obtained by a phase separation reaction composed of
Using these hollow fiber membranes, an internal pressure total amount filtration type hollow fiber membrane filter module having a membrane area of 20 m 2 was produced.
This hollow fiber membrane module was installed at the cooling tower entrance of the replenishing water line of the cooling tower using groundwater (replenishing water amount 1 m3 / hour).

For (A), the flux was 50 L / m2 / hour (A-1), 10 L / m2 / hour (A-2) for two levels, and (B) for 50 L / m2 / hour (B-1). .
The total hardness of the makeup water was 800 mg / L, and a large amount of scale adhered to the fins around 30 days before installation.
When observed after 30 days (A-1), no scale adherence to the fins was observed, and a precipitate was observed at the bottom of the drain pan. When analyzed, the main component was calcium carbonate. As a result, the effect of the present invention was confirmed.
On the other hand, in (A-2) and (B-1), the scale adherence to the fin was almost the same as before the installation, and the effect of the present invention was not recognized.

A sintered compact cartridge with an outer diameter of 64 mm, an inner diameter of 44 mm, and a length of 10 inches is obtained by pressurizing and heat-treating an ion exchange resin mainly composed of resorcinol having a particle size of 0.2 mm together with a solvent in a concentric circular molder. A filter was obtained.
The cartridge filter had a blocking hole diameter of 0.06 μm.
This cartridge filter was installed and tested at the finish washing water entrance (washing water supply rate 1000 L / hr) of a hotel dishwasher using a mixture of groundwater and tap water.
The total hardness of the mixed water of this groundwater and tap water was 550 mg / L, and the drying line of the dishwasher had a scale attached. After this scale was physically peeled and washed, a cartridge filter was installed and treated at 360 L / m 2 / hour (C).
As a result, in C, no scale was generated in the drying line, and the effect of the present invention was confirmed.

A hollow fiber membrane filter module of 10 m2 composed of a hollow fiber membrane filter having a blocking hole diameter of 0.01 μm (D) made of polyvinylidene fluoride and a blocking hole diameter of 0.25 μm (E) made of a polyethylene hollow fiber membrane is used for a mold water tube boiler. Installed at the makeup water entrance.
D was treated with a flux of 50 L / m2 / hour (D-1), 10 L / m2 / hour (D-2) and E was treated with a flux of 300 L / m2 / hour (E). The total hardness of water supplied to this water tube boiler was 600 mg / L, and the components were mainly calcium and silica.

When the water pipe was inspected two months after the installation, a large amount of scale adhered to the water pipe without the filter module (blank). However, no adhesion of scale was observed in D, and precipitates of calcium and silica were detected in the discharge water from the makeup water discharge port. D-2 was less than the blank, but scale removal was required. E was almost the same as the blank.
Thus, the effect of the present invention was clearly confirmed.

As is clear from the above experimental examples, the water activation effect by the method of the present invention is proved.
The present invention is a cheap and permanent scale prevention means by a simple facility without using chemicals, and utilizes an electrochemical water activation effect and can be used in various fields.
For example, the present invention can be applied to various boilers, heat exchangers and their flow reduction units, water washing dryers, and the like, and is useful as a revolutionary scale prevention technology.
That is, at the time of receiving water, a water filtration device specified by the present invention is arranged immediately before landing in the water receiving tank, or a boiler, a heat exchanger, a dishwasher, etc. that are problematic due to the occurrence of scale, etc. Then, it can achieve by providing the water filtration apparatus specified by this invention in the water introduction part to a terminal device.

Such a breakthrough effect is that water is transformed due to the electrochemical action of water, which is a feature of the present invention, and an activated state appears, and effects such as scale prevention can be reliably obtained. And it is in the point of operating continuously.
Furthermore, this effect is effective in preventing slimming and red rust prevention by sterilization, and it is believed that the effect of the present invention is industrially significant.

Claims (2)

The main part of the constituent material is a synthetic polymer substance, the blocking pore diameter is at least 0.2 μm or less, or the molecular weight cut off is 1 million or less, the path during filtration is almost bent, and the path length of the bent channel is a straight line Using a filter made of filtration media that is configured to form at least four times the flow path due to static voids, water to be treated having a total hardness of 550 to 800 mg / L is treated with a filtration flux of 50 L / m 2 / hour or more. A method for preventing the scale from adhering to water . The method for preventing adhesion of water scale according to claim 1, wherein the main part of the constituent material is composed of only a synthetic polymer substance.