JPS61254293A - Method for preventing contamination of permeable membrane - Google Patents

Abstract

PURPOSE:To reduce the washing frequency of a permeable membrane, by forming a polisher apparatus from a mixed bed consisting of an anion exchange resin bed, a strong basic anion exchange resin bed and a strong acidic cation exchange bed. CONSTITUTION:Pure water with high purity sterilized by ultraviolet rays is introduced into a polisher apparatus 3 which comprises a mixed bed consisting of a perfectly regenerated anion exchange resin bed, an almost perfectly regenerated strong basic anion exchange resin bed and an almost perfectly regenerated strong acidic cation exchange bed. The pure water with high purity flowed out from the polisher apparatus 3 is further supplied to a membrane separation apparatus 4 having a permeable membrane based on polyacrylonitrile or polyaminde to remove a fine nonionic substance and the flowed-out pure water with ultra-high purity, purified to a high degree is supplied to a use point and utilized.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a membrane separation device included in a secondary ultrapure water production system around the point of use of ultrapure water production equipment for semiconductor manufacturing, medical manufacturing, etc. The present invention relates to a method for preventing contamination of a permeable membrane.

[Prior art]

Semiconductor manufacturing and pharmaceutical manufacturing require highly purified ultrapure water, so-called ultrapure water, which contains very few solutes, particulates, viable bacteria, and the like.

In recent years, with the consolidation of these industries, even more careful
Ultrapure water with a purity close to Ritsugu's value is amended. Ultrapure water is usually produced by a combination of systems as shown below, and the functions of each system are: the pretreatment system removes colloids, and the next system removes colloids from most 1iL screens. , removal of fine particles, chemical compound 1, etc., the secondary thread system is aimed at precision finishing of the high purity pure water obtained with the primary thread system.

The ultrapure water produced by combining the above systems is supplied to each use point through piping, but in order to prevent contamination within the supply piping, the secondary system is used differently from the primary thread system. Often installed in Kinteki Point 0 The secondary system is usually a sterilizer such as ultraviolet rays or ozone, a polisher device with a built-in ion exchange resin layer, and a membrane component with a built-in reverse osmosis membrane or ultrafiltration group * In particular, the Membrane #l device is configured to prevent water from permeating through the ultrapure water production secondary thread system in order to prevent fine nonionic substances from entering the ultrapure water. It is said that the device is essential for membranes that have a built-in permeable membrane that has the ability to allow microscopic nonionic substances to pass through, but not to pass through fine nonionic substances.

However, the membrane separator of this secondary ultrapure water production system collects fine particles on the surface of the permeable membrane that were not treated in the primary system.
When trace amounts of non-ionic substances such as organic substances eluted from the piping material supplying high-purity water are captured, these substances form ice on the membrane surface, increasing pressure loss and reducing the production of ultra-pure water. Please decrease.

Therefore, when the pressure loss of the membrane separator reaches a predetermined value, the permeation group is fc-purified to recover the permeation membrane. The permeable membrane is normally cleaned every 20 to 30 days, but this cleaning process requires very high levels of salt content to keep the entire secondary system sterile. It requires a large amount of money.

C'A Ming's Purpose] Therefore, the present invention aims to reduce the frequency of cleaning a permeable membrane of a membrane separation device in an ultrapure water production system, particularly in a secondary thread system.

[Structure of the invention]

In order to achieve the above object, the present invention processes high-purity pure water from a primary ultrapure water production system in the order of a sterilizer, a polisher, and a membrane separation device with a built-in permeable membrane to produce ultrapure water. In the secondary ultrapure water production system, which is supplied with ultrapure water, as a polisher, an anion exchange resin layer and a mixed layer of a strong basic ion exchange resin and a strong acid cation exchange resin are used. The purpose of the present invention is to achieve the above object by using a polisher device.

In the ultrapure water production process, which is the primary field of the present invention, tap water, well water, river water, etc. are used as raw water, and pretreatment is performed depending on the quality of the raw water. As a pre-processing system, there is a samurai process,
It is carried out by combining filtration treatment, activated carbon treatment, etc.

The raw water that has passed through the pre-treatment system is then supplied to the primary system where it is made into high-purity pure water. This is carried out by combining a water purification device and a reverse osmosis membrane device for removing colloidal silica. This-
Most electrolytes, particulates, living bacteria, etc. are removed in the secondary system, and the quality of the high-purity water flowing out from the secondary system is usually resistivity / θ ~ / 1 MΩ - mouth, particulates / Q θ
~O001@/'d, the number of viable bacteria/Q pieces/- or less is the goal.

- The high-purity pure water produced in the secondary system is then passed through the secondary thread system to remove 11L solutes, particulates, raw materials, etc. that could not be captured by the primary system, and sheath it into ultrapure water. Ru. The figure is a 70-diagram of a secondary ultrapure water production system to which the present invention is applied.

In the figure, 7 is a pure water tank, which stores high-purity pure water produced by the primary thread system.

The pure water is first introduced into the ultraviolet clarification device λ.

The ultraviolet sterilizer λ uses the sterilizing effect of ultraviolet light to
Ultraviolet rays are irradiated to sterilize living germs such as bacteria in 6-firA degree pure water, and the wavelength is around 2 t Onm and the irradiation amount is around 10,000 μW/sec.

The ultraviolet sterilized high-purity water is then introduced into a polisher t3 to which the present invention is applied.

The polisher device 3 consists of an almost completely regenerated anion exchange resin layer and an almost completely regenerated mixed layer of a strongly basic ion exchange resin and a strongly acidic cation exchange resin.
Ru.

Highly purified water is purified by contacting the anion exchange resin layer with a mixed layer of a strong basic ion exchange resin and a strong acidic cation resin in this order. This is a polisher device in which it is essential to provide a completely neutralized anion exchange resin layer before a mixed layer of a strongly basic porous ion exchange resin and a strongly acidic cation exchange resin.

For this purpose, a new ion exchange tower filled with an anion exchange resin is installed in front of an ion exchange tower consisting of a mixed layer of a strongly basic anion exchange resin and a strongly acidic cation exchange resin. Any method may be employed in which a basic anion exchange resin and a strong acid cation exchange resin are regenerated outside the system and mixed to form a cartridge, which holds an ion exchange resin layer.

The high-purity water flowing out from the polisher device described above is further supplied to a membrane separation device having a built-in permeable membrane mainly made of polyacrylonitrile, polyamide, polysulfone, or the like.

Here, particularly fine non-ionic substances that could not be removed by conventional treatments are removed, and the highly purified ultra-high purity water that flows out is supplied to the point of use as ultra-pure water for use. be done.

The quality of this ultra-pure water is exclusively for electricity transmission /g~//MΩ-mouth, the number of fine particles-〇~! The number is θ pieces/- or less, and the raw number/pieces/- or less.

At that time, Toru i! Fine non-ionic substances remain on the surface of the membrane, increasing pressure loss, but since the structure of the present invention passes through the polisher device 3, the membrane separation device Pressure losses are significantly reduced.

In the secondary system of the ultrapure water production process, is it possible to reduce pressure loss in the membrane separator by supplying high-purity pure water that has passed through the polisher device configured according to the present invention to the membrane separator? Although it is not clearly understood, when fine nonionic substances pass through the anion exchange resin layer, their properties change to make them difficult to adhere to the permeable membrane surface, and as a result, they exit the system together with the concentrated water. This is thought to be due to the decrease in permeable membrane contamination due to outflow, and this phenomenon of decreasing permeable membrane contamination is due to certain:
! It does not cause hail on the membrane.

The gap ion exchange resin employed in the ion exchange resin layer of the polisher 1tiIK in the present invention may be either strongly basic, weakly basic, porous, or gel, but since the basicity is moderate, the strong base The bow 2 shape is preferable from the viewpoint of durability and stain resistance. And the liquid passing speed is SVj″Q
~10θhr−1 vicinity is adopted.

The mixing ratio of strongly basic anion exchange resin and strongly acidic cation exchange resin in the mixed layer is strong base anion exchange resin two strongly acidic cation exchange resins = /2/~λ2/ in terms of volume ratio. Ru.

Furthermore, a gel type ion exchange resin is employed as the mixed layer.

〔Example〕

Next, the present invention will be explained with reference to Examples, but the present invention is not limited to the following Examples.

Example / Cation exchange tower filled with tap water and strongly acidic cationic fecal fat SX/B (manufactured by Sankyen Kasei Korai Co., Ltd., hereinafter simply referred to as SK/B), strongly basic anion Replacement resin SA/θ
After water was sequentially passed through an ion exchange tower filled with A (manufactured by San-ai Kasei Kogyo Co., Ltd., hereinafter referred to as single KBA10A), water was passed through a reverse osmosis device equipped with a reverse osmosis membrane 80-3100 (manufactured by Toshi Co., Ltd.). Processing was carried out at an operating pressure of jkg/d and a recovery rate of rj%, and the water was passed through a minx bed volisher consisting of a mixed side force upper layer with a ratio of EIK/B and 8A/Qk/nico (volume ratio). Row - The effluent water was made into high purity pure water.

The regeneration level of the mixed bed polisher is /θ0jl-HO1/ for SK/B and io for SA #7A.

1-NaOH/l-resin.

The average quality of the high purity water was as shown in Table 1.

Ultrapure water was produced using the ultrapure water production process secondary system of the flow diagram shown in FIG.

The high-purity pure water was once stored in a high-purity pure water tank made of FRP and then supplied.

GWO-/124tP (Tokyo Shibaura Electric Co., Ltd.) was used as the ultraviolet sterilizer, and the wavelength CO! The irradiation time was set to be nm and the irradiation time to be aO seconds.

The polisher device of the present invention, which follows the ultraviolet sterilization device, mixes regeneration level 30 (#-Mol/) at a ratio of Kazuki/:2 (volume ratio) and fills it into a cartridge-type column. A strong basic anion exchange resin ph:zi2 (manufactured by Mitsubishi Chemical Industries, Ltd., hereinafter referred to as PA3/2) in the same amount as the mixed resin was light-filled on top of the resin.

What is the playback level of PA3/2? θOJ, l -NaOH/
It was made into t-resin. Also, SV is jOhr-',
For the membrane sheath plate, use ultra-v5 membrane AOL-1010 (manufactured by Asahi Kasei Corporation) and apply pressure to the input chamber! ~/d
, it was possible to operate with a recovery rate of 0.

Ultrapure water was produced by passing day-purity pure water through the secondary thread system as described above, and the pressure change in the membrane separator at that time was as shown in Figure 2.

The average quality of the ultrapure water was as shown in Table 1.

Table 2 Comparative Example/The polisher was regenerated using the secondary system used in Example/ under the same conditions as Example/. The mixture was mixed at a volume ratio of 1 to 2, and filled into a cartridge 2 column to form a polisher device.Other experimental conditions were the same as in Example 1, and changes in pressure during membrane separation were investigated.

The results were as shown in Figure 2.

EXAMPLE: P is laminated on top of the mixed resin of SK/B and 8A#7A of the polisher device using the secondary system used in Example/.
The filling amount of A3/co was changed, and the other conditions were the same as those in Example/1, and the pressure changes in the membrane dividing device 3θ days after the start of operation were compared.

The results were disappointing, as shown in Figure 3.

〔Effect of the invention〕

According to the method of the present invention, the frequency of cleaning the permeable membrane of the membrane separation device in the secondary thread system of the ultrapure water production system can be reduced.

[Brief explanation of drawings]

FIG. 7 is a diagram showing a flow diagram of the secondary system of the ultrapure water production system. In the figure, 7 is a high-purity pure water tank, = is an onion killing device, 3 is a polisher device, and Z is a membrane separation device. is an ultrapure water supply conduit,
B shows the ultrapure water supply conduit. Figure 2 shows the change in pressure in the exchange pit and direct in the example/comparative example/, and the vertical axis is the pressure (kfl/cx
i), the horizontal axis indicates the number of days of water flow (days). Figure 3 shows the membrane separation device 30 days after the start of operation when the amount of strongly basic anion exchange resin layered on top of the mixed layer of strongly basic anion exchange resin and strongly acidic cation exchange resin was varied. shows the change in pressure. The vertical axis is pressure (#/-) and the horizontal axis is PA3/eV (/
/Hr). Patent Hosodai Nippon Rensui Co., Ltd. Agent Patent Attorney For Acceptance - 7 others No. 1 Mi No. 2 Zutsutsu 7th & (Sun)

Claims (1)

[Claims] (1) Highly purified water from the primary ultrapure water production system,
In an ultrapure water production secondary system configured to pass through a sterilizer, a polisher, and a membrane separator with a built-in permeable membrane in order and supply it as ultrapure water, an anion exchange resin is used as the polisher. A method for preventing contamination of a permeable membrane, characterized by using a polisher device comprising a layer and a mixed layer of a strongly basic anion exchange resin and a strongly acidic cation exchange resin.