JPH07195072A - Ultra-pure water producing apparatus - Google Patents

Abstract

PURPOSE:To efficiently remove TOC eluting from a non-regeneration type mixed bed system ion exchanger of a secondary treatment system by basically installing an anion exchange resin single bed exchanger of a non-regeneration type in the rear stage of the mixed bed system ion exchanger. CONSTITUTION:This ultra-pure water producing apparatus treats the water treated in a primary treatment system further with the secondary treatment system having the mixed bed ion exchanger of the non-regeneration system. In such a case, the anion exchange resin single bed exchanger of the nonregeneration type is installed in the rear stage of the mixed bed ion exchanger. For example, the primary treatment system is composed of a regeneration type cation exchange column K, a decarbonation column D, a regeneration type anion exchange column A, a reverse osmosis treatment RO and the regeneration type mixed bed ion exchange column MB. The secondary treatment system is composed of a UV sterilization device UVST, the non-regeneration type ion exchange device, the non-regeneration type anion exchange resin single bed ion exchange device, an ultrafilter membrane device UF and a storage tank TK.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrapure water production system for producing ultrapure water used in semiconductor device manufacturing processes, and more particularly to an ultrapure water production system having a reduced TOC concentration.

[0002]

2. Description of the Related Art A conventional ultrapure water production system comprises a pretreatment system for performing coagulation and filtration as shown in FIG. 3 and a regenerative cation exchange column K for primary treatment of pretreated water. ,
Decarbonation tower D, regenerative anion exchange tower A, reverse osmosis membrane device R
O, a primary treatment system consisting of a regenerative mixed bed type ion exchange column MB, etc., and an ultraviolet sterilizer UV _ST for further secondary treatment of primary pure water obtained from this primary treatment system, H in the column
A secondary type consisting of a non-regenerative mixed bed type ion exchange device, an ultrafiltration membrane device UF, and a storage tank TK filled with a mixed resin of a strong acidic cation exchange resin and an OH strong basic anion exchange resin It is usually composed of a processing system.

Although ultrapure water produced by using these devices contains almost no impurities, higher water quality is required with the recent increase in the integration density of semiconductor devices. However, a trace amount of organic matter (T
At present, it is difficult to reduce OC) more easily.
One of the reasons for this is the elution of TOC from the non-regeneration type mixed bed type ion exchange device which is a constituent unit of the secondary treatment system. The strongly acidic cation exchange resin and the strongly basic anion exchange resin packed in the ion exchange device are made of a polymer compound that is an organic substance, and since the contact surface area with water is large, these ion exchange resins The elution of TOC from water is unavoidable. In the conventional non-regeneration type mixed bed type ion exchange device, since the strongly acidic cation exchange resin and the strongly basic anion exchange resin are mixed, the TO
Although the elution of C is considerably small, in recent years, it has been proposed to further suppress the elution of TOC by setting the mixing ratio of them so that the ratio of the strongly acidic cation exchange resin is high. (Japanese Patent Laid-Open No. 1-224090
issue). However, as described above, further reduction of TOC in ultrapure water is desired, and such conventional non-regeneration type mixed bed ion exchange apparatus is insufficient to suppress TOC elution. .

[0004]

As a result of various studies to solve the above problems, the present inventors have found that an anion exchange resin is provided in the subsequent stage of the conventional non-regenerative type mixed bed ion exchange apparatus. By installing a single bed type ion exchange device or as a non-regeneration type mixed bed type ion exchange device, a mixed resin prepared by mixing a strongly acidic cation exchange resin and a strongly basic anion exchange resin, and an anion. By stacking and packing the exchange resin in the same tower, by using a mixed bed type ion exchange device configured to pass the water to be treated from the layer of the mixed resin in the order of the layer of the anion exchange resin, The present inventors have completed the present invention by knowing that TOC eluted from a non-regeneration type mixed-bed ion exchange device of a secondary treatment system, particularly a strongly acidic cation exchange resin used in the device can be efficiently removed. That Where the target is to provide a very TOC concentration low ultrapure water production system.

[0005]

In order to achieve the above object, the present invention is a super treatment in which water treated in a primary treatment system is further treated in a secondary treatment system equipped with a non-regeneration type mixed bed ion exchange device. In a pure water production system, a non-regeneration type anion exchange resin single-bed ion exchange device is installed after the mixed bed type ion exchange device. The water flow SV of the apparatus is set to be larger than the water flow SV of the non-regeneration type mixed bed type ion exchange apparatus.

Further, the present invention is an ultra-violet oxidation device installed in the flow path between the non-regeneration type mixed bed type ion exchange device and the non-regeneration type anion exchange resin single bed type ion exchange device. This is a pure water production system.

Further, the present invention provides an ultrapure water producing system for treating water treated in a primary treatment system in a secondary treatment system further provided with a non-regeneration type mixed bed type ion exchange system, wherein the mixed bed type ion exchange system is used. As a device, a mixed resin obtained by mixing a strongly acidic cation exchange resin and a strongly basic anion exchange resin, and an anion exchange resin are stacked in the same column and packed, and the water to be treated is the mixed resin. The invention provides an ultrapure water production system using a mixed bed type ion exchange system configured to pass water in the order of the layer 1 to the anion exchange resin layer.

According to the apparatus of the present invention having the above-mentioned structure, the layer of the mixed resin of the H-type strongly acidic cation exchange resin and the OH-type strongly basic anion exchange resin, especially the TOC eluted from the cation exchange resin is used. Further, it can be effectively adsorbed and removed by the subsequent layer of the OH type anion exchange resin alone.

Further, an ultraviolet oxidizer is installed in a flow path between the non-regeneration type mixed bed type ion exchange apparatus and the non-regeneration type anion exchange resin single bed type ion exchange apparatus, whereby the mixed bed Both the TOC component eluted from the cation exchange resin of the ion exchange system and the TOC component eluted from the anion exchange resin can be decomposed into low-molecular organic acid and CO ₂ and these organic acids can be decomposed. And CO ₂
Can be easily removed by the anion exchange resin single bed type ion exchange apparatus in the subsequent stage, so that it becomes possible to obtain ultrapure water having a lower TOC concentration.

The present invention will be described in detail below.

FIG. 1 is a block diagram showing an embodiment of the present invention. In this embodiment, the ultrapure water production system includes a pretreatment system, a regenerative cation exchange tower K, a decarbonation tower D, a regenerative anion exchange tower A, a reverse osmosis membrane device RO, and a regenerative mixed bed type ion. Primary treatment system consisting of exchange tower MB, UV sterilizer UV _ST , H-type strong acid cation exchange resin and OH in the tower.
-Regeneration type mixed-bed type ion exchange device filled with a mixed resin with a strong base anion-exchange resin, non-regeneration type anion-exchange resin single-bed type ion exchange device, ultrafiltration membrane device UF,
It is composed of a secondary treatment system including a storage tank TK.

In this construction, the pretreatment apparatus is constructed by an appropriate combination of techniques such as coagulation / precipitation and filtration according to the purity of raw water, and these are constructions known to those skilled in the art.

As for the primary processing system, known ones can be used as they are.

In the secondary treatment system, the primary treated water in the storage tank TK is an ultraviolet sterilizer UV _ST , a non-regeneration type mixed bed type ion exchange device, a non-regeneration type anion exchange resin single bed type ion exchange device, and UF. After each processing, it is repeatedly taken out at the course point and used, and the rest is returned to the storage tank TK. That is, the secondary treated water is constantly circulated in the secondary treatment system through the flow path.

Here, the storage tank TK and the ultraviolet sterilizer U
As V _ST , non-regeneration type mixed bed type ion exchange device, and UF, all known ones can be used.

The UV sterilizer UV _ST is preferably one which mainly contains UV irradiation wavelengths near 254 nm.

The non-regeneration type mixed bed type ion exchange apparatus contains H type strongly acidic cation exchange resin and OH type strongly basic anion exchange resin in a volume ratio of 2: 1 to 1: 2. It is preferable that the mixture is mixed so that the mixture is filled.

The non-regeneration type anion exchange resin single bed type ion exchange apparatus is one in which an OH type strong basic anion exchange resin and / or an OH type weakly basic anion exchange resin is filled. The anion exchange resin used is preferably a strongly basic one because it has a large TOC removing ability.

Further, it is preferable to set the water flow SV of the non-regeneration type anion exchange resin single bed type ion exchange device to be larger than the water flow SV of the non-regeneration type mixed bed type ion exchange device. Water flow SV of the ion exchange device of type: Water flow SV of the ion exchange device of mixed bed is preferably 3: 1 to 30: 1.

The reason is that the concentration of TOC eluted from the resin layer is almost inversely proportional to the water flow SV, and therefore the water flow SV of the single bed ion exchange device is the same as the water flow SV of the mixed bed ion exchange device.
This is because, if the ratio of to TO is smaller than 3, the increase in the amount of TOC eluted from the single bed ion exchange device cannot be ignored. The upper limit of the ratio is limited to about 30: 1 in terms of the water passing SV ratio because of the restriction that the speed should not hinder the actual water passing operation.

The non-regeneration type mixed bed type ion exchange apparatus and the non-regeneration type anion exchange resin single bed type ion exchange apparatus are
Normally, the same water flow rate is used for operation, and in such a case, the ratio of the water flow SV is inversely proportional to the volume ratio of the ion exchange resin filled in each ion exchange device. Therefore, as described above, the water flow SV of the single-bed ion exchange device: the water flow SV of the mixed-bed ion exchange device =
In order to control 3: 1 to 30: 1, the ratio of the volume of the anion exchange resin packed in the single-bed ion exchange device to the volume of the mixed resin packed in the mixed-bed ion exchange device is 1 /.
It may be 3: 1 to 1/30: 1.

FIG. 2 is a block diagram showing another embodiment of the present invention.

In this example, an ultraviolet oxidizer UV _OX is provided in the flow path between the non-regeneration type mixed bed ion exchange device and the non-regeneration type anion exchange resin single bed type ion exchange device. Has the same configuration as that of the above embodiment.

As UV _OX , a known UV oxidizer can be used. This one is for irradiating ultraviolet rays containing many wavelengths around 185 nm, and the irradiation amount is 100-500.
W · h / m ³ is preferable.

Although the primary processing system and the secondary processing system are configured as described above in each of the above embodiments, the present invention is not limited to this, and can be applied to all known primary processing systems and known secondary processing systems. The configuration can be changed appropriately according to the purpose of the present invention.

Further, in the above embodiment, a conventionally known mixed bed type ion exchange apparatus, in which a mixed resin of a strongly acidic cation exchange resin and a strongly basic anion exchange resin is filled in the column, and the column A single bed type ion exchange device filled only with anion exchange resin was configured separately, but the configuration is not limited to this.
For example, the mixed resin and the anion exchange resin are laminated and packed in two layers in one resin tower to be integrated, and the water to be treated is passed from the mixed resin layer to the anion exchange resin alone layer in this order. The configuration may be good, and various changes may be made without departing from the scope of the invention.

[0027]

【Example】

Example 1 Industrial water was treated with a pretreatment device consisting of a coagulation-sedimentation device and a sand filter, and then a regenerated cation exchange filled with a strongly acidic cation exchange resin Amberlite (registered trademark, the same applies hereinafter) IR-124. Tower, decarbonation tower, and regenerated anion exchange tower filled with strong basic anion exchange resin Amberlite IRA-402BL for sequential treatment, and then attached with reverse osmosis membrane SU-710 manufactured by Toray Industries, Inc. Treated with the reverse osmosis membrane device, and further treated by passing water through a regenerative mixed bed type ion exchange device filled with Amberlite IR-124 and Amberlite IRA-402BL in a volume ratio of 1: 1. Specific resistance 18.2 MΩ · cm, TOC concentration 2.4p
Primary pure water of pb was obtained. The above is the primary processing system.

The primary pure water was sterilized by using an ultraviolet sterilizer SX-1 / 2 type manufactured by Chiyoda Kousou Co., Ltd. using a high pressure mercury lamp, and then special conditioning and regeneration were performed in advance. The H-type strongly acidic cation exchange resin Amberlite IR-124 and the OH-type strongly basic anion exchange resin IRA-402BL were mixed at a volume ratio of 1: 1 and filled with a mixed resin. Amberlite I, an OH-type strongly basic anion exchange resin, which has been treated by passing water through a non-regeneration type mixed bed type ion exchange device at a water flow rate of SV50, and then subjected to special conditioning and regeneration in advance.
The non-regeneration type anion exchange resin single bed type ion exchange device filled with RA-402BL was treated by passing water at SV = 150.

At this time, the TOC concentration of the treated water at each point of the outlet of the ultraviolet sterilizer (UV _ST ), the outlet of the non-regeneration type mixed bed type ion exchange device, and the outlet of the non-regeneration type anion exchange resin single bed type ion exchange device The measurement results of are summarized in Table 1.

The TOC is measured by T manufactured by Organo Corporation.
The measurement was performed using an OC meter and an Olga Tok. Examples 2 and 3 The water flow SV of the non-regeneration type anion exchange resin single bed type ion exchange apparatus in Example 1 was 300 (Example 2) or 1
The treatment was performed under the same conditions as in Example 1 except that the value was set to 500 (Example 3).

Treated water TOC at each point at this time
The concentration measurement results are summarized in Table 1.

[0032]

[Table 1] Example 4 Between the non-regeneration type mixed bed type ion exchange apparatus and the non-regeneration type anion exchange resin single bed type ion exchange apparatus in Example 1,
TFL-4 manufactured by Chiyoda Kousaku Co., Ltd. using a low pressure mercury lamp
Type UV oxidizer (which can irradiate UV light with wavelength around 185 nm) is installed, and treated water of non-regeneration type mixed bed type ion exchange device is UV oxidizer (UV _OX ), non-regeneration type anion exchange resin single bed type Water was treated in the order of the ion exchange device.

At this time, the water flow rate of the non-regeneration type mixed bed type ion exchange device was SV50, and the water flow SV of the non-regeneration type anion exchange resin single bed type ion exchange resin was 150. Also,
The irradiation dose of the ultraviolet oxidation device was 300 W · h / m ³ .

The other conditions are the same as those in the first embodiment.

Table 1 shows the measurement results of the TOC concentration of the treated water at each point.

From each of the above examples, by installing the non-regeneration type anion exchange resin single bed type ion exchange device in the subsequent stage of the non-regeneration type mixed bed type ion exchange device, ultrapure water having a further lower TOC concentration can be obtained. It is clear that this is possible.

Further, when an ultraviolet oxidizer is installed between the non-regeneration type mixed bed type ion exchange apparatus and the non-regeneration type anion exchange resin single bed type ion exchange apparatus, further TOC reduction can be achieved. .

In the above-mentioned Examples 1 to 3, the conventional non-regeneration type mixed bed type, in which only the mixed resin prepared by mixing the strongly acidic cation exchange resin and the strongly basic anion exchange resin is filled An example of installing a non-regeneration type anion exchange resin single bed type ion exchange device in the latter stage of the ion exchange device was shown, but both ion exchange devices were integrated, that is, strong acid cation exchange resin and strong base. A mixed resin formed by mixing a cationic anion exchange resin and an anion exchange resin are stacked and packed in the same tower, and the water to be treated is formed in this order from the layer of the mixed resin to the layer of the anion exchange resin alone. The same effect was obtained by using a non-regenerative mixed bed ion exchange device configured to pass water.

[0039]

As for the ultrapure water production system of the present invention, the non-regeneration type anion exchange resin single-bed type ion exchange is provided after the conventional non-regeneration type mixed bed type ion exchange device in the secondary treatment system. Since a new non-regeneration type mixed bed type ion exchange device of a type in which these devices are installed or both of these devices are integrated is used, the TOC concentration in the obtained ultrapure water can be greatly reduced. Further, when the ultraviolet oxidation device is provided in the flow path between the conventional mixed bed type ion exchange device and the anion exchange resin single bed type ion exchange device, the TOC can be further reduced.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of the present invention.

FIG. 2 is a configuration diagram showing another embodiment of the present invention.

FIG. 3 is a configuration diagram showing an example of a conventional ultrapure water production apparatus.

[Explanation of symbols]

K Regeneration type cation exchange tower D Decarbonation tower A Regeneration type anion exchange tower RO Reverse osmosis membrane device MB Regeneration type mixed bed type ion exchange device UV _ST UV disinfection device UF Ultrafiltration membrane device TK Storage tank UV _OX UV oxidation device

Claims (5)

[Claims] 1. An ultrapure water production system in which water treated in a primary treatment system is further treated in a secondary treatment system equipped with a non-regeneration type mixed bed type ion exchange device, in the latter stage of the mixed bed type ion exchange device. An ultrapure water production system characterized in that a non-regeneration type anion exchange resin single-bed type ion exchange system is installed. 2. The water flow SV of the non-regeneration type anion exchange resin single bed type ion exchange device is set to be larger than the water flow SV of the non-regeneration type mixed bed type ion exchange device. The ultrapure water production system according to claim 1. 3. An ultraviolet oxidation device is installed in a flow path between the non-regeneration type mixed-bed ion exchange device and the non-regeneration type anion-exchange resin single-bed ion exchange device. The ultrapure water production system according to claim 1. 4. An ultrapure water production system in which water treated in a primary treatment system is further treated in a secondary treatment system equipped with a non-regeneration type mixed bed type ion exchange device, wherein the mixed bed type ion exchange device comprises: A mixed resin obtained by mixing a strongly acidic cation exchange resin and a strongly basic anion exchange resin, and an anion exchange resin are stacked and packed in the same tower, and water to be treated is added from the layer of the mixed resin. An ultrapure water production system using a mixed bed type ion exchange system configured to pass water in the order of anion exchange resin layers. 5. The mixed resin and anion exchange resin according to claim 4, wherein the strongly acidic cation exchange resin and the strongly basic anion exchange resin are mixed, and the volume of the anion exchange resin is the mixed resin. An ultrapure water production system, which is filled so as to be smaller than the volume.