JPH08173961A - Warm ultra pure water producing apparatus - Google Patents

Abstract

PURPOSE: To provide pure water with high purity and at the same time extend the life of a filtration membrane by producing a high precision filtration membrane and an ultrafilter membrane from metal films which are produced by forming a metal powder layer on a wire net, respectively. CONSTITUTION: A heating means 1 is installed in a container 2 to make raw water be warm water. The raw water made to be warm is filtered by a separating apparatus 3 with high precision filtration membrane and an ultrafilter membrane separating apparatus 4. Also, after the raw water is introduced into a reverse osmosis separating apparatus RO5 and an ion-exchange apparatus 6, the raw water is further introduced into a ultraviolet-ray sterilizing apparatus 7 and an ion-exchange apparatus 8 installed in series. In this case a metal membrane in which a porous layer is formed by applying a metal powder to the surface of a pressed wire net made of a stainless steel and sintering the resulting metal net is used as a filtration membrane of the separating apparatus 3 and the ultrafilter membrane separating apparatus 4. Consequently, pure water with high purity can be obtained and at the same time the life of the filtration membrance is extended.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for producing hot ultrapure water used in semiconductor manufacturing factories and the like.

[0002]

2. Description of the Related Art In a factory for manufacturing precision parts such as semiconductors, ultrapure water is used for cleaning products. An apparatus for producing this ultrapure water is, for example, a pretreatment apparatus including a microfiltration membrane separation apparatus and an ultrafiltration membrane separation apparatus, a primary pure water production apparatus including a reverse osmosis membrane separation apparatus and an ion exchange apparatus, It is composed of a secondary pure water production system including an ultraviolet sterilization system and an ion exchange system. According to the above ultrapure water device,
Raw water such as city water, groundwater or industrial water is filtered by a pretreatment device to separate agglomerates, and then the permeated water is passed through a primary pure water production device to remove TOC (total organic carbon) components. Then, ultrapure water can be obtained by decomposing the TOC component by the secondary pure water device. In recent years, a higher cleaning effect has been required as the degree of integration of semiconductors has improved, and in order to satisfy this requirement, the use of ultrapure water (warm ultrapure water) heated to about 70 ° C. has been studied.

[0003]

However, when hot ultrapure water is produced by the conventional ultrapure water producing apparatus, there are the following problems. In a conventional ultrapure water production system, a resin membrane formed of an organic polymer such as cellulose, vinyl polymer or aromatic polymer is used as a filtration membrane in a microfiltration membrane separation device and an ultrafiltration membrane separation device. Therefore, when the raw water heated to the above-mentioned temperature is passed through, there arises a problem that a part of the resin film is eluted and the purity of the pure water is lowered, and the resin film is deteriorated by heat and its life is shortened. . Therefore, an object of the present invention is to solve the above-mentioned problems of the prior art, and to provide a hot ultrapure water production system capable of obtaining high-purity pure water and extending the life of the filtration membrane.

[0004]

In order to achieve the above object, in the present invention, a heating means for heating raw water is provided, and
A pretreatment device including a microfiltration membrane separation device and an ultrafiltration membrane separation device for filtering warmed raw water, a primary pure water production device including a reverse osmosis membrane separation device and an ion exchange device, and an ultraviolet sterilizer A secondary pure water producing apparatus including an ion exchange apparatus, wherein the microfiltration membrane separation apparatus and the ultrafiltration membrane separation apparatus apply metal powder to the surface of a pressed stainless steel wire mesh and sinter it. The technical means of having the obtained metal film in which the porous layer was formed was adopted.

[0005]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a system diagram showing an example of a hot ultrapure water producing apparatus suitable for carrying out the present invention. As shown in FIG. 1, a heating means 1 such as a heater is installed in a container 2 to heat the raw water. Introduce raw water at a temperature of 23 to 25 ° C into the container 7
The raw water which has been heated to about 0 ° C. and warmed is filtered by the microfiltration membrane separation device (MF) 3 and the ultrafiltration membrane separation device (UF) 4. Subsequently, the raw water is reverse osmosis membrane separation device (RO)
5 and the ion exchange device 6, and then the ultraviolet sterilization device 7 and the ion exchange device 8 are placed in series. Here, up to the ultrafiltration membrane separation device 4 is referred to as a pretreatment device 9, up to the ion exchange device 6 is referred to as a primary pure water production device 10, and up to the ion exchange device 8 is referred to as a secondary pure water production device 11. , 12 are the pipes for introducing raw water.

That is, city water, industrial water, ground water, etc. are first introduced into the pretreatment device 9 and heat-treated in the container 2 to enhance the cleaning efficiency, and precision water is removed to remove aggregates and impurities of the treated water. It is introduced into the filtration membrane separation device 3 and the ultrafiltration membrane separation device 4 and subjected to membrane separation.

The pretreated water treated by such a pretreatment device 9 is then subjected to RO membrane separation treatment by the reverse osmosis membrane separation device 5 in the primary pure water producing device 10 and further ionized by the ion exchange device 6. Will be exchanged.

Further, the treated water of the primary pure water producing apparatus 10 is introduced into the ultraviolet sterilizing apparatus 7 in the secondary pure water producing apparatus 11, the TOC contained therein is ionized or decomposed, and of these, it is ionized. The organic substance is removed by the ion exchange device 8 later, and hot ultrapure water is obtained.

By the way, in order to improve the cleaning performance of ultrapure water, when heat treatment is performed at the above-mentioned temperature and hot ultrapure water is passed through each device, in the microfiltration membrane separation device and the ultrafiltration membrane separation device. Since a resin membrane formed of an organic polymer such as cellulose, vinyl polymer or aromatic polymer is usually used as the filtration membrane, a part of the resin membrane is eluted and the purity of the hot ultrapure water is reduced. In addition, there is a problem that the resin film is deteriorated by heat and its life is shortened.

On the other hand, in the present invention, a metal membrane having a porous layer obtained by coating and sintering metal powder on the surface of a pressed stainless steel wire mesh is used as a microfiltration membrane separation device and Used for filtration membranes in ultrafiltration membrane separators.

Specific examples of the metal film include a sintered product of stainless steel fibers, a stainless steel wire net, or a metal powder layer formed on a substrate obtained by pressing down a metal net. Among these, it is preferable in terms of mechanical strength and filtration performance. The above metal film may be formed, for example, as follows. First tatami or rather weave wire mesh (stainless steel or Ti etc.)
Is rolled (reduction rate 10 to 50%) and a slurry (solid content concentration 50 to 75 wt%) in which a binder (polyvinyl alcohol) is dispersed in a solution (water) is applied, dried and sintered, and Rolling (reduction ratio 2 to 10%) if necessary. Example of making metal film Base plate: Rolling a flat mesh weave wire mesh (SUS316) of 1.4 mm in thickness and 200 mesh (reduction ratio 40%) → thickness of 0.
Created a board with 24mm and 42μm mesh size. Powder layer: 70 parts of SUS317L powder having an average particle size of 9.5 μm, 1 part of polyvinyl alcohol and 29 parts of water are mixed → Coated on a substrate (thickness 60 μm) → Drying → 105 in a hydrogen atmosphere
0 ° C., 1 hr sintering → pore diameter 0.1-0.3 μm.

[0012]

As described above in detail, according to the present invention, the metal powder is applied to the surface of the stainless steel wire mesh which is pressed down by the filtration membrane in the microfiltration membrane separation device and the ultrafiltration membrane separation device and sintered. By using the metal film having the porous layer thus obtained, the following effects can be obtained. (1) Since the metal membrane has heat resistance, even if hot ultrapure water is passed through the microfiltration membrane separation device and the ultrafiltration membrane separation device, impurities do not elute from the metal film due to heat, and It is possible to prevent a decrease in purity. (2) By using the metal membrane in the microfiltration membrane separation device and the ultrafiltration membrane separation device, the life of the filtration membrane for hot ultrapure water can be extended.

[Brief description of drawings]

FIG. 1 is a system diagram showing an embodiment of an apparatus for producing hot ultrapure water suitable for producing hot ultrapure water according to the present invention.

[Explanation of symbols]

1 ... Heating means, 2 ... Container, 3 ... Microfiltration membrane separation device, 4
... ultrafiltration membrane separation device 5 ... reverse osmosis membrane separation device, 6 ... ion exchange device, 7 ... ultraviolet sterilization device, 8 ... ion exchange device, 9 ... pretreatment device, 1
0 ... Primary pure water producing apparatus, 11 ... Secondary pure water producing apparatus, 12
… Introduction piping

Claims (1)

[Claims] 1. A heating means for warming raw water, a microfiltration means for purifying the warmed raw water, an ultrafiltration means for purifying the permeated water, and a reverse osmosis membrane means for purifying the permeated water. In the apparatus for producing hot ultrapure water having a sterilizing means for sterilizing the permeated water, the microfiltration membrane and the ultrafiltration membrane are characterized by comprising a metal membrane having a metal powder layer formed on a wire mesh. Water production equipment.