JPS6014610B2 - Pre-coating method for powdered ion exchange resin - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides primary reactor cooling water, condensate water for reactor feed water,
For pre-coat agent holding bodies in transitors or desalters used for purifying water or wastewater such as nuclear fuel pool water, low conductivity waste liquids from industrial waste treatment equipment, and other industrial waste liquids, such as thermal power generation condensate. This invention relates to a method for precoating powdered ion exchange resin.

The term "powdered ion exchange resin" as used herein refers to a granular ion exchange resin having a particle diameter of about 5 to 250 grains, or an ion exchange resin pulverized into this range. Conventionally, in order to pre-coat the holder using a powdered ion exchange resin as a pre-coating agent, pre-coating is carried out by introducing an aqueous slurry in which an ion exchange resin and an anion exchange resin are thoroughly mixed into a transfer vessel or a desalter. It has been done.

However, when positive and negative ion exchange resins are mixed in clean water, the resins aggregate together and form nodules, making pre-coating difficult. As a method for controlling such excessive agglomeration of the resin and enabling pre-coating of the resin, Japanese Patent Publication No. 16325/1987 discloses adding a water-dropable resinous polyelectrolyte such as polymethyl acrylate to the resin mixture. A method including this is described.

However, this method has drawbacks such as the addition of the electrolyte and the necessity of operations to confirm that the agglomeration of the powdered resin after addition is within the required range. In other words, this method seems reasonable at first glance as it neutralizes the amount of static electricity and weakens the cohesive force by adding a full base of electrolyte, but it is necessary to manage and adjust unstable electrolytes that are prone to deterioration, and confirm the extent of the effect after addition. Therefore, it is necessary to sample the slurry each time adjustment is made, which has the disadvantage of being extremely troublesome in terms of operation management and operation.

In addition, in terms of performance, the added base adds a harmful electrolyte, which increases unfavorable factors in terms of ion exchange performance and adsorption and removal of suspended matter in water. The present invention eliminates the above-mentioned deficiencies regarding pre-coating of pre-coated sieves or demineralizers and eliminates excessive agglomeration of powdered cation-anion exchange resins in a simple manner without adding water-soluble resinous polyelectrolytes. The purpose of this method is to provide a method for forming a good precoat layer on a holder by preventing the progress of the precoat layer, and the method involves keeping the concentration of the resin aqueous slurry forming the precoat layer fed to the filter or desalter at a constant concentration. This is done by controlling the range.

In other words, by supplying the resin slurry at a specific low concentration to the transfer vessel, the number of collisions of resin particles is reduced, the cohesive force due to electrostatic action is weakened, and the conventionally used water-soluble resin polyelectrolyte is added. This is to suppress the excessive baby-booming effect.

When it is diluted less than 0.01% by weight, the agglomeration effect is reduced, so that agglomeration is excessively suppressed, and the precoat layer becomes too dense, resulting in high water flow resistance, which is not preferable.

It also has the disadvantage that the time required for precoating is long. On the other hand, if the resin slurry concentration exceeds 0.0% by weight, the aggregation effect will increase, agglomeration will be promoted, and the uniformity of the precoat layer will be lost.

The precoating concentration used in conventional methods is usually 1% by weight.
That's about it.

According to the present invention, the concentration of the resin aqueous slurry supplied to the precoat filter or desalter is 0.01 to 0.06% by weight.
controlled by.

In one embodiment of the present invention, resin is mixed with water in a resin feed tank to form an aqueous slurry, the slurry is suction diluted by an ejector, and then mixed and diluted with circulating water to obtain a resin in a predetermined concentration range. Form an aqueous slurry. In this case, a slurry of about 8% by weight is formed in a resin feed tank, diluted to about 4% in an ejector, and then diluted with circulating water to make a slurry of 0.01 to 0.0% by weight. is preferred. In order to form a uniform and good pre-coat layer, usually put a specified amount of pure water into a resin feed tank, add healthy ion exchange resin, and boil for about 10 minutes, then add intestinal ion exchange resin and reduce the amount of water. After adjusting, I bowed for about 20 minutes.

It is preferable to leave the rope or pods for 5 to 4 hours because the longer the time for leaving the chicks or the pods, the slower the agglomeration of the resin will be. However, there is no difference in effectiveness even if it is left in place for a longer period of time. Pre-coating is 3-7.3
It is preferable to carry out the process at a linear flow rate of 200 m/h/300 m area, and it is preferable to carry out the precoating for a time of 2 to 1' field time.

Examples will be described below with reference to the drawings. In FIG. 1, an appropriate amount of pure water is poured into the resin feed tank 8 and the rope punch machine 9 is started. The Takaazusa machine 9 has a rotation speed of 0 to 25 pm.
Use a device that can be adjusted arbitrarily between the two and has sufficient strength. After adding the anion exchange resin and allowing sufficient lighting, the intestine ion exchange resin was added, pure water was added to adjust the resin concentration, and the intestine was further heated for approximately 20 minutes. The mixing ratio of both negative and positive ion exchange resins is intestinal ion exchange resin/anion exchange resin = 1 to 3/1, and the total weight is about lk 9. dry resin/〆. The mixing ratio of the ion exchange resin is not limited to the above ratio, but is determined depending on the water quality conditions at the location where the purification system of the present invention is installed.

The concentration of the resin slurry in the resin feed tank 8 is approximately 8
%.

It is preferable to make this concentration as high as possible because the container can be made smaller;
This problem occurs when the concentration is high, and uniform dispersion is not good, making quantitative extraction and transfer of the slurry difficult, so it is determined by the properties of the slurry and consideration in the process. The turret 1 shown in FIG. 1 is used as a pre-coat type sieve or decoat device. Tank 1
The device is a rigid device having a raw water inlet at the bottom, a filtration water outlet at the top, a precoat agent holder 3 in the middle, and a dispersion plate 2 below it, and is equipped with a resin drain mechanism (not shown in the drawings). Pre-fill the required amount of pure water in the tank 1 and the pre-coat tank 4, start the pre-coat pump 5, gradually open the valve 17, and while watching the flow meter 7, set the source overflow velocity to about 37'h and the overflow area. After the circulation, the valve 16 is opened, the driving water 12 of the ejector 11 is adjusted by the flow meter 13, and the slurry valve 15 is opened. The resin slurry concentration 14 to the inlet of the precoat pump 5 is controlled by the ejector driving water 12 and the slurry valve 15.
It can be adjusted as desired.

In this example, the resin slurry concentration was kept at about 4% or less, and the resin slurry was diluted with circulating water to the following concentration and supplied to the transit tower. Pre-coat progress can be checked using the bell gauge 10.

As shown in FIG.
1 consists of a wire mesh 18 that is supported in the tank by 1
The resin in the thinned resin slurry supplied to the V is held on the wire mesh 18 to form a resin precoat layer 19. After a predetermined precoat layer is formed, the ejector driving water 12 is stopped and the slurry valve 15 is closed. In addition, when purifying raw water using a pre-coated filtration device, the pre-coat is then maintained, and the water intake valve is opened while maintaining a circulation flow rate of at least 1 k/h/saru area and the untreated water is passed through to retain the pre-coat agent. This is done by stopping the pump and draining the water at an appropriate depth and overspeed.

The precoating conditions were as follows when the concentration of the precoating resin slurry was changed as described above.

Observation is based on visual appearance (the cassette is made of transparent acrylic) Flow rate is 3.7'h, area of filtration is ○: Good precoat: The surface of the precoat layer is flat and uniform ×: Poor precoat: The surface of the precoat layer is noticeably uneven. It will not be uniform.

Δ: Precoat somewhat good: Irregularities may occur on the surface of the precoat layer.

Therefore, the precoat slurry concentration is normally 0.04% and a maximum of 0.06% is allowed.

According to the method of the present invention, a precoating conditioner such as a water-repellent resinous polyelectrolyte is not required in the precoating of the precoat type sieve, so that the related operations are not necessary and the operation becomes simple.

Furthermore, in the method of the present invention, since the precoat agent slurry is supplied to the sieving tank at a constant concentration, the amount of precoat can be adjusted as desired.

In the conventional method, the necessary brecoat agent is put into a precoat tank to prepare a slurry, and the entire amount is precoated using a circulation line from the precoat tank to the filter to the precoat tank. Since the resin slurry concentration in the tank changes, it cannot be stopped midway, but according to the method of the present invention, the necessary amount of resin is added to the resin feed tank any number of times to form a slurry, and the required amount of precoat for each time is determined. It can be checked with a level gauge, and the necessary pre-coating agent for multiple filter tanks can be added to the resin feed tank.
Continuous precoating can be performed by checking the precoating tank corresponding to each transition tank using the level gauge of the resin feed tank.

[Brief explanation of drawings]

FIG. 1 is a flow sheet of an embodiment of the present invention, and FIG. 2 is an explanatory diagram of a precoat agent support portion. 1...Cast, 3...Precoat agent holder, 4
...Pre-coat tank, 8...Resin feed tank, 10...Level gauge, 11...Ejector. Figure 1 Figure 2

Claims (1)

[Claims] 1. A method for precoating a powdered ion exchange resin on a precoating agent holder of a precoating type filter or a precoating type demineralizer, using water and a powdered ion exchange resin having a particle size of about 5 to 250 μm, 0.01 powdered ion exchange resin
A method for precoating a powdered ion exchange resin, which comprises preparing an aqueous slurry containing 0.06% by weight, and supplying the aqueous slurry to the precoating type filter or precoating type demineralizer for precoating. 2. In a method of precoating a powdered ion exchange resin on a precoat agent holder of a precoat type filter or a precoat type demineralizer, water and a powdered ion exchange resin with a particle size of about 5 to 250 μm are mixed in a resin feed tank. A highly concentrated slurry of powdered ion exchange resin is prepared, and the highly concentrated slurry of powdered ion exchange resin is sucked from the resin feed tank by a water ejector and mixed with the precoat circulating water, and the powdered ion exchange resin in the mixed aqueous slurry is Concentration from 0.01 to 0
．． A method for pre-coating a powdered ion exchange resin, characterized in that pre-coating is performed by supplying the resin to the pre-coating type filter or pre-coating type demineralizer as 0.6% by weight. 3. In a method of precoating a powder ion exchange resin on a precoat agent holding body of a precoat type filter or a precoat type demineralizer, the powder ion exchange resin is coated with water and a powder ion exchange resin having a particle size of about 5 to 250 μm. 01～
The aqueous slurry was adjusted to contain 0.06% by weight, and
A method for pre-coating a powdered ion exchange resin, characterized in that the aqueous slurry is supplied and pre-coated at a linear flow rate of ~7.3 m/h.