TW201404455A - Ultrapure water production apparatus - Google Patents

Abstract

The topic of the invention is to provide an ultrapure water production apparatus with small quantity of reverse osmosis membrane separation apparatus. To solve the problem, an ultrapure water production apparatus is provided, which comprises a primary pure water system (2) and an auxiliary system (3) utilized to process the treated water from the primary pure water system (2) The primary pure water system (2) is at least provided with the reverse osmosis membrane separation apparatus. The ultrapure water production apparatus of the invention is characterized in that the reverse osmosis membrane separation apparatus disposed on the primary pure water system (2) of the ultrapure water production apparatus is a high pressure type reverse osmosis membrane separation apparatus, and is configured with a single-stage mode. The high pressure type reverse osmosis membrane separation apparatus is characterized in that standard operating pressure is 5.52MPa, pure water flux is over 0.5m<SP>3</SP>/m<SP>2</SP>.D, and the removal rate of NaCl is over 99.5% (NaCl 32000mg/L).

Description

Ultrapure water manufacturing device

The present invention relates to an ultrapure water production apparatus, and more particularly to an ultrapure water production apparatus including a primary pure water system having a reverse osmosis membrane separation apparatus (RO apparatus).

In the past, the ultrapure water used as the semiconductor washing water was composed of the pretreatment system 1', the primary pure water system 2', and the auxiliary system (secondary pure water system) 3' as shown in FIG. The ultrapure water production facility is produced by processing raw water (industrial water, tap water, well water, used ultrapure water discharged from a semiconductor factory (hereinafter referred to as "recycled water"), and the like. In Figure 2, the function of each system is as follows.

The pretreatment system 1' is constituted by a coagulation, a pressurized floating (precipitation), a filtration (membrane filtration) device or the like to remove suspended substances, colloidal substances, and the like in the raw water. In this process, a polymer organic substance, a hydrophobic organic substance, or the like can also be removed.

The primary pure water system 2' having a reverse osmosis membrane separation (RO) apparatus, a deaeration apparatus, and an ion exchange apparatus (mixed bed type, or a 4-bed 5-tower type) removes ions, organic components, and the like in the raw water. Further, in the reverse osmosis membrane separation device, salts are removed, and ionic and colloidal TOC are removed. In the ion exchange apparatus, salts are removed, and the TOC component adsorbed or ion-exchanged by the ion exchange resin is removed. In the deaerator, inorganic carbon (IC) and dissolved oxygen (DO) are removed.

In the auxiliary system 3' having a low-pressure ultraviolet ray oxidizing device, an ion exchange pure water device, and an ultrafiltration membrane separation device, the purity of the pure water obtained in the primary pure water system 2' is further improved to become ultrapure water. In a low-pressure ultraviolet ray oxidizing apparatus, TOC is decomposed into an organic acid and decomposed into CO ₂ by ultraviolet rays having a wavelength of 185 nm emitted from a low-pressure ultraviolet lamp. The organic matter and CO ₂ produced by decomposition are removed, and the ion exchange resin in the subsequent stage is removed. In the ultrafiltration membrane separation device, the fine particles are removed, and the effluent particles of the ion exchange resin are removed.

In Fig. 2, the reverse osmosis membrane separation device of the primary pure water system is disposed on the front side and the last section, but is also arranged in two stages in series. In Fig. 2, the pretreatment system has only one system, but there is also a thin exhaust wastewater recovery system that is arranged in parallel to treat tap water, industrial water pretreatment system, and waste water discharged from the semiconductor manufacturing process. The situation.

Patent Document 1: Japanese Patent No. 3468784

In the past, in the primary pure water or waste water recovery system of the ultrapure water production system, according to the purpose of reducing the concentration of organic matter, the RO method in which the RO separation device is connected in two stages in two stages is used. The standard operating pressure is 0.75 MPa and the pure water flux is 25 m ³ /m ² ‧D/branch, because it is the raw water for industrial water treatment, tap water, well water or low-grade wastewater with low salt load.英吋) The above-mentioned ultra-low pressure RO membrane, or a low pressure RO membrane with a standard operating pressure of 1.47 MPa and a pure water flux of 25 m ³ /m ² ‧D/branch (8 inches).

However, when the reverse osmosis membrane separation device is set to two stages as described above, the installation space is increased, and the operation management of the apparatus is also complicated. That is, in the ultrapure water manufacturing equipment of a semiconductor manufacturing plant, depending on the scale, there will be a reverse osmosis membrane separation device of the first stage of the primary pure water system, for example, 4 to 40, and in the second stage, The reverse osmosis membrane separation device is disposed in parallel with the same extent as the first stage, and the reverse osmosis membrane separation device is provided in an extremely large number, and the equipment cost and management cost of the reverse osmosis membrane separation device are increased, and the installation area is also large.

The present invention has been developed in order to solve the above conventional problems, and an object of the invention is to provide an ultrapure water production apparatus having a small number of reverse osmosis membrane separation apparatuses.

The ultrapure water production apparatus of the present invention is provided with a primary pure water system and an auxiliary system for treating the treated water of the primary pure water system, and at least the primary pure water system is provided with a reverse osmosis membrane separation device. The reverse osmosis membrane separation device provided in the primary pure water system is a high pressure type reverse osmosis membrane separation device and is disposed in a single stage.

The high-pressure reverse osmosis membrane separation device has a characteristic of a normal operating pressure of 5.52 MPa or more, a pure water flux of a standard operating pressure of 0.5 m ³ /m ² ‧D or more, and a NaCl removal rate of 99.5% (NaCl 3 2000 mg/L) or more. good.

The apparatus of the present invention may further have a processing system for treating the raw water, and the treated water of the pretreatment system is sequentially processed by the primary pure water system and the auxiliary system. The TDS (total dissolved solids) of the feed water to the high pressure type reverse osmosis membrane separation device may be 1500 mg/L or less.

The film surface effective pressure of the high pressure type reverse osmosis membrane separation device is preferably 1.5 to 3 MPa.

The high-pressure type reverse osmosis membrane separation device has been conventionally used in seawater desalination equipment, and the membrane surface effective pressure (the difference between the primary side pressure and the secondary side pressure) is performed by reverse osmosis membrane treatment of seawater having a high salt content. It is used as a high pressure of about 5.52 MPa.

In the present invention, the high pressure type reverse osmosis membrane separation apparatus is disposed in a single stage (1 stage) in a primary pure water system of an ultrapure water production apparatus. In general, a seawater desalination reverse osmosis membrane contributes to a compact molecular structure of a skin layer such as desalination and organic matter removal, and therefore has a high organic matter removal rate. In the case of the desalination of the seawater, since the concentration of the salt of the raw water is high, the osmotic pressure is high. Therefore, in order to secure the amount of permeated water, the effective pressure of the membrane surface is 5.5 MPa or more. In addition, in the field of the electronics industry, the concentration of the salt used in the raw water of the general RO membrane is low, and the TDS (total dissolved solids) is 1,500 mg/L or less. In such raw water, the osmotic pressure is low, and a sufficient permeate amount can be obtained with a membrane pressure of only about 2 to 3 MPa, and as described above, the water quality of the permeated water is higher than that of the conventional reverse osmosis membrane (ultra-low pressure RO membrane, low pressure RO membrane) ), a substantial increase.

Thus, by providing the high-pressure type reverse osmosis membrane separation device in a single pair in a single pure water system, the number of reverse osmosis membrane separation devices is half the number of the conventional two-stage arrangement, thereby making reverse osmosis The installation space of the membrane separation device is halved, and the equipment cost and operation management cost are also roughly halved.

Hereinafter, embodiments of the ultrapure water producing apparatus of the present invention will be described in detail.

In the present invention, as shown in FIG. 1, when it is desirable that the prior treatment system 1, the primary pure water system 2, and the auxiliary system 3 sequentially process the raw water to produce ultrapure water, the primary pure water system 2 is set in a single stage as a single stage. A high pressure type reverse osmosis membrane separation device of a reverse osmosis membrane separation device (RO device).

In the past, the high-pressure reverse osmosis membrane separation device is a reverse osmosis membrane separation device used for seawater desalination, and has a standard operating pressure of 5.52 MPa or more, and a pure water flux of 0.5 m ³ /m ² ‧D or more at a standard operating pressure. The NaCl removal rate was 99.5% (NaCl 32000 mg/L) or more. This NaCl removal rate was a removal rate at 25 ° C for a NaCl aqueous solution having a NaCl concentration of 32000 mg/L. The catalogue of reverse osmosis membranes (including technical data) is displayed by the membrane manufacturer and can be judged as high pressure type, low pressure type or ultra low pressure type by catalog value.

This high-pressure type reverse osmosis membrane has a firmer surface layer on the surface of the membrane than a low-pressure or ultra-low pressure reverse osmosis membrane used in a pure water system of an ultrapure water manufacturing apparatus. Therefore, the high pressure type reverse osmosis membrane is lower than the low pressure type or ultra low pressure type. In the permeable membrane, although the membrane permeation amount per unit operating pressure is low, the organic matter removal rate is extremely high. When the feed water having a salt concentration of 1500 mg/L or less of TDS (total dissolved solids) is subjected to reverse osmosis membrane treatment, the osmotic pressure applied to the reverse osmosis membrane at a recovery condition of 90% is at most about 1.0 MPa. Therefore, in the case of using a high-pressure type reverse osmosis membrane separation apparatus for the treatment of the feed water of TDM 1500 mg/L or less, it is desirable to have a membrane surface effective pressure of about 1.5 to 3 MPa, more preferably about 2 to 3 MPa (1 side pressure and 2 The difference in secondary pressure) ensures the same amount of water as the low pressure or ultra low pressure reverse osmosis membrane. As a result, it is possible to obtain the same treated water quality and treated water amount as the conventional two-stage RO by the one-stage RO membrane treatment, thereby reducing the number of membranes, the container, and the piping, and achieving low cost and space saving.

The film shape of the reverse osmosis membrane is not particularly limited, and may be, for example, any of a 4-inch RO membrane such as a spiral type or a hollow type, an 8-inch RO membrane, and a 16-inch RO membrane.

In Fig. 1, the prior processing system 1 processes the raw water and supplies it to the primary pure water system 2, but a thin exhaust wastewater treatment system (not shown) may be provided in parallel with the pretreatment system 1, and the thin row The treated water of the wastewater treatment system is also supplied to the primary pure water system. In this case, in the flow of Fig. 1, a water tank is provided in the front stage of the primary pure water system 2, and the treated water from the pretreatment system 1 and the treated water of the lean waste water treatment system are flowed into the water tank.

[Examples] <Experimental Example 1>

The wastewater discharged from the electronic device factory (electrical conductivity 100 mS/m, TDS 600 mg/L, TOC 10 mg/L) was passed through a high-pressure type reverse osmosis membrane separation device (RO membrane was set at a recovery rate of 73%). SWC4+: Nitto Denko (share) system; the operating rate of 5.52 MPa is 24.6 m ³ /m ² ‧D, and the NaCl removal rate is 99.8% (NaCl 32000 mg/L)). As a result, the TOC of the permeated water was 0.85 mg/L. The effective pressure of the membrane surface was 2.0 MPa.

<Experimental Example 2>

In the previous stage, the recovery rate of RO was 75%, the recovery rate of RO in the latter stage was 90%, and the overall recovery rate was 73% (the latter stage RO concentrated water and the previous stage RO water supply), and the same electronic device factory waste water as in Experimental Example 1 was filled with super-filled water. Two-stage RO unit of low-pressure RO membrane (ES-20; manufactured by Nitto Denko Corporation). As a result, the TOC concentration of the first stage RO permeate water was 1.35 mg/L, and the TOC concentration of the second stage RO permeate water was 0.9 mg/L. The effective pressure of the membrane surface is 0.5 MPa in the first stage and 0.75 MPa in the second stage.

From the above Experimental Examples 1 and 2, it was confirmed that the water in the single stage of the high pressure type reverse osmosis membrane separation apparatus and the ultra low pressure type reverse osmosis membrane separation apparatus were passed through the water to obtain the same water permeation water. Further, it was confirmed that in Experimental Example 2, the TOC concentration of the RO permeated water in the first stage was extremely high at 1.35 mg/L, and in the single stage of the ultra-low pressure type reverse osmosis membrane separation device, the removal of TOC and TDS was higher. The type of reverse osmosis membrane separation device is low.

Therefore, when using the above high pressure type reverse osmosis membrane separation device, The primary pure water system of the ultrapure water manufacturing apparatus of the existing process shown in Fig. 2 is separately provided as the high pressure type reverse osmosis membrane separation apparatus shown in Fig. 1, and the membrane surface effective pressure is operated as 2.0 MPa. It was confirmed that the ultra-pure water of the same water quality can be produced by the same amount of production water as the conventional (two-stage RO membrane, the membrane surface effective pressure of the first stage of 0.5 MPa, and the membrane surface effective pressure of the second stage of 0.75 MPa).

The present invention has been described in detail above using specific embodiments, but it is not necessary to be able to carry out various modifications without departing from the scope of the invention.

In addition, the content of the present application is based on the application of the entire contents of the Japanese application filed on May 25, 2011 (Japanese Patent Application No. 2011-117142).

1‧‧‧Pre-treatment system

2‧‧‧A pure water system

3‧‧‧Auxiliary system

Fig. 1 is a system diagram showing an example of an embodiment of an ultrapure water producing apparatus of the present invention.

Fig. 2 is a system diagram showing a conventional ultrapure water production apparatus.

1‧‧‧Pre-treatment system

2‧‧‧A pure water system

3‧‧‧Auxiliary system

Claims (4)

An ultrapure water manufacturing device is provided with a primary pure water system and an auxiliary system for treating the treated water of the primary pure water system, and at least the ultrapure water manufacturing device of the reverse osmosis membrane separating device is provided in the primary pure water system. The reverse osmosis membrane separation device disposed in the primary pure water system is a high pressure reverse osmosis membrane separation device, and is disposed in a single stage manner. The ultrapure water manufacturing apparatus according to the first aspect of the patent application, wherein the high pressure type reverse osmosis membrane separating apparatus has a pure water flux of 0.5 m ³ /m ² ‧D with a standard operating pressure of 5.52 MPa or more and a standard operating pressure The above and the characteristics of NaCl removal rate of 99.5% (NaCl 32000 mg/L) or more. The ultrapure water manufacturing apparatus according to claim 1 or 2, wherein the ultrapure water manufacturing apparatus further has a processing system for processing raw water, and the treated water of the pretreatment system is sequentially processed by the first pure water system and the auxiliary system. The TDS of the feed water to the high pressure type reverse osmosis membrane separation device is 1500 mg/L or less. The ultrapure water producing apparatus according to any one of claims 1 to 3, wherein the high pressure type reverse osmosis membrane separating apparatus has a membrane surface effective pressure of 1.5 to 3 MPa.