TW201942067A - Ultrapure water production system and ultrapure water production method - Google Patents

Abstract

The purpose of the present invention is to provide an ultrapure water production system and an ultrapure water production method, which make it possible to produce high-purity pure water stably over a long period of time. Provided is an ultrapure water production system 1 that includes an ultrafiltration membrane device 2 and a filtration membrane device 3 which are connected in series, and that produces ultrapure water by treating treatment-water with the ultrafiltration membrane device 2 and the filtration membrane device 3, in that order, wherein: the ultrafiltration membrane device 2 has a removal rate of 99.99% or more of fine particles having a particle diameter of 20 nm or more; and the filtration membrane device 3 is oxidizing agent resistant, and is equipped with a filtration membrane having a pore size of 2-40 nm. Also provided is an ultrapure water production method.

Description

Ultrapure water manufacturing system and method

The invention relates to an ultrapure water production system and an ultrapure water production method.

Conventionally, ultrapure water used in semiconductor manufacturing processes has been manufactured using an ultrapure water manufacturing system. The ultrapure water production system is, for example, removing the suspended matter in the raw water to obtain the aforementioned treated water processing unit, and using a reverse osmosis membrane device or an ion exchange device to convert the total organic carbon (TOC) component or ionic component of the treated water. The primary pure water production department that removes and produces primary pure water, and the secondary pure water production department that removes a very small amount of impurities in primary pure water and produces ultrapure water. As the raw water system, in addition to municipal water, well water, groundwater, and industrial water, ultra-pure water (hereinafter, referred to as "" Recycled water ").

In the secondary pure water manufacturing department, primary pure water is highly processed through an ultraviolet oxidation device, an ultrafiltration membrane (UF) device of an ion exchange pure water device, and the like, to generate ultrapure water. The ultrafiltration membrane device is disposed near the last stage of the secondary pure water production unit, and removes particles generated from ion exchange resin and the like.

However, the requirements for high purity of ultrapure water systems are increasing year by year. For example, the concentration of microparticles requires the number of microparticles with a particle diameter of 50 nm or more and 1000 pcs./L or less. In addition, the water quality system is required to become more stringent, and the particle diameter is required to be less than 50 nm, for example, the reduction of fine particles of about 10 nm. Therefore, a method of highly removing fine particles having a smaller particle diameter has been proposed (for example, refer to Patent Documents 1 and 2).

In addition, for the purpose of improving the water quality of ultrapure water, there is also a method for removing contaminated parts or granular shape components generated in the upstream of ultrapure water equipment by using an ultrafiltration membrane device arranged at the extreme end (for example, refer to Example Document 3).
[Prior technical literature]
[Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2016-64342
[Patent Document 2] International Publication No. 2015/050125
[Patent Document 3] Japanese Patent Application Laid-Open No. 10-99855

[Questions to be Solved by the Invention]

However, the conventional ultrafiltration membrane device used for the removal of fine particles has insufficient resistance to oxidants, and gradually deteriorates through hydrogen peroxide in water. It is also known that the ultrafiltration membrane device itself generates waste materials. . Therefore, there is a problem that it is difficult to obtain ultrapure water with reduced particles for a long period of time.

An object of the present invention is to provide an ultrapure water production system and an ultrapure water production method that can obtain ultrapure water with reduced particles over a long period of time.

[Means for solving problems]

The ultrapure water manufacturing system of the present invention includes an ultrafiltration membrane device and a filtration membrane device connected to the ultrafiltration membrane in series, and the treated water is sequentially processed in the ultrafiltration membrane device and the filtration membrane device. The ultrapure water production system for producing ultrapure water is characterized in that the removal rate of the fine particles having a particle diameter of 20 nm or more in the ultrafiltration membrane device is 99.8% or more, and the filter membrane device is provided with: oxidant resistance and a pore size of 2 Filter film of ~ 40 nm.

In the ultrapure water production system of the present invention, it is preferable that the ultrafiltration membrane device has an ultrafiltration membrane with a molecular weight cut-off of 3000 to 10,000. The ultrafiltration membrane device is preferably an ultrafiltration membrane using polyfluorene, polyvinylidene fluoride, or polytetrafluoroethylene as a material.

In the ultrapure water production system of the present invention, it is preferable that the filter membrane device has a filter membrane using polyvinylidene fluoride or polytetrafluoroethylene as a material.

The ultrapure water manufacturing system of the present invention is provided on the above-mentioned ultrafiltration membrane device, and further has a hydrogen peroxide removal device. The treated water of the hydrogen peroxide removal device is used as the to-be-processed water, and can be used in the ultrafiltration membrane device and It is preferable that the above-mentioned filter membrane device sequentially processes.

The ultrapure water production system of the present invention is provided on the above-mentioned ultrafiltration membrane device, and according to this, an ultraviolet oxidation device, a hydrogen peroxide removal device, a degassing membrane device, and a non-renewable mixed-bed ion exchange resin device are sequentially provided. It is preferable that the treated water of the non-regenerating type mixed-bed ion exchange resin device be treated as the treated water in the aforementioned ultrafiltration membrane device and the aforementioned filtration membrane device in order.

The ultrapure water manufacturing method of the present invention is characterized in that water to be treated is passed through an ultrafiltration membrane device, and the removal rate of 99.8% or more is used to process particles with a particle diameter of 20nm or more, and the treated water of the aforementioned ultrafiltration membrane device is processed. Water-passing is performed by a filter membrane device having an oxidation resistance and a filter membrane having a pore diameter of 2 to 40 nm.

In the method for producing ultrapure water of the present invention, it is preferable that the water to be treated in the ultrafiltration membrane device contains hydrogen peroxide in an amount of 0.1 to 3 μg / L.

[Inventive effect]

According to the ultrapure water production system and the ultrapure water production method according to the present invention, ultrapure water with reduced particles can be obtained for a long time.

Ultrafiltration membranes are generally more resistant to oxidants such as hydrogen peroxide. Accordingly, when the supply water of the ultrafiltration membrane contains a hydrogen peroxide concentration, for example, if the concentration is about 0.1 to 3 μg / L, it is understood that the degradation of the membrane through the hydrogen peroxide is not caused. However, in the case of long-term water passing through the ultrafiltration membrane, the material quality of the treated water after long-term water passing through the ultrafiltration membrane, especially the concentration of fine particles in the water, will be different. For the low concentration of hydrogen peroxide as described above, it is understood that there are also some influencers for the membrane. In addition, in the case where water is passed for a long period of time by using an ultrafiltration membrane having stronger oxidant resistance, it is found that the deterioration of water quality is relatively mild, and the present invention has been completed.

Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings. As shown in FIG. 1, the ultrapure water production system 1 related to this embodiment includes a pre-treatment section 10, a primary pure water production section 11, a liquid tank 12, and a secondary pure water production section 13, and the secondary pure water The manufacturing section 13 includes an ultrafiltration device 2 and a filtration membrane device 3 for removing fine particles in water in this order. The pre-treatment section 10 and the primary pure water production section 11 are both provided as necessary.

In the ultrapure water production system 1 according to this embodiment, as the ultrafiltration membrane device 2, an ultrafiltration membrane device having a particle diameter of less than 50 nm or more and having a fine particle removal rate of about 20 nm is used as the filtration membrane. As the device 3, a filtration device using an ultrafiltration membrane having an oxidant resistance is used. According to this, through the ultrafiltration membrane device 2, while the fine particles as described above are highly removed, and those waste materials at the time of deterioration are captured by the filter membrane device 3, ultrapure particles with high degree of long-term removal can be obtained. Waterman.

Hereinafter, other devices included in the ultrafiltration water production system 1 of the present embodiment, the filtration membrane device 3 and the ultrapure water production system 1 as necessary, will be described.

The pre-processing section 10 removes suspended matter from the raw water, generates pre-processed water, and supplies the pre-processed water to the primary pure water manufacturing section 11. The pre-processing unit 10 is, for example, a sand filter, a precision filter, or the like, which is suitably selected to remove suspended matter in the raw water, and is provided with a heat exchanger for adjusting the temperature of the water to be treated as necessary. Make up. However, the quality of the raw water may be omitted by omitting the pre-treatment section 10.

Raw water is, for example, water used in municipal water, well water, groundwater, industrial water, semiconductor manufacturing plants, etc., and is recovered and treated (reclaimed water).

The primary pure water production department 11 is equipped with reverse osmosis membrane equipment, degassing equipment (decarbonation tower, vacuum degassing equipment, degassing membrane equipment, etc.), ion exchange equipment (cation exchange equipment, anion exchange equipment, mixed bed ion exchange). Equipment, etc.), and an ultraviolet oxidizing device, it is suitable to combine and construct one. The primary pure water production unit 11 removes ionic components and non-ionic components in the pre-treated water, dissolves a gas to produce primary pure water, and supplies the primary pure water to the liquid tank 12. The primary pure water system has, for example, a total organic carbon (TOC) concentration of 5 μg C / L or less, a resistivity of 17 MΩ ･ cm or more, and a particle number of 100,000 psc./L or less.

The liquid tank 12 stores primary pure water, and supplies the required amount to the secondary pure water production section 13.

The secondary pure water production unit 13 removes a trace amount of impurities in the primary pure water to produce ultrapure water. As shown in FIG. 2, the secondary pure water production unit 13 is, for example, on the upstream side of the ultrafiltration membrane device 2 and includes: a heat exchanger (HEX) 4, an ultraviolet oxidation device (TOC-UV) 5, and hydrogen peroxide removal. A device (H ₂ O ₂ removal device) 6, a degassing membrane device (MDG) 7, and a non-regenerating mixed-bed ion exchange resin device (Polisher) 8 are configured. However, the secondary pure water production section 13 does not necessarily include the above-mentioned device, and may be adopted as long as it is configured as necessary.

The heat exchanger (HEX) 4 adjusts the temperature of the primary pure water supplied from the liquid tank 12 as necessary. The temperature of the primary pure water whose temperature is adjusted in the heat exchanger 4 is preferably 25 ± 3 ° C.

The ultraviolet oxidizing device (TOC-UV) 5 irradiates ultraviolet rays to the primary pure water whose temperature is adjusted in the heat exchanger 4 to decompose and remove trace organic matters in the water. The ultraviolet oxidizing device 5 includes, for example, an ultraviolet lamp, and generates ultraviolet rays in the vicinity of a wavelength of 185 nm. The ultraviolet oxidizing device 5 may further generate ultraviolet rays in the vicinity of a wavelength of 254 nm. When ultraviolet rays are irradiated to water in the ultraviolet oxidizing device 5, ultraviolet rays decompose water to generate OH radicals, and the OH radicals oxidize and decompose organic substances in water. In an ultraviolet oxidation device, when excessive ultraviolet irradiation is performed, OH radicals that do not contribute to the oxidative decomposition of organic substances react with each other to generate hydrogen peroxide. The generated hydrogen peroxide may deteriorate the ultrafiltration membrane included in the downstream ultrafiltration membrane device 2.

Therefore, in order to reduce the hydrogen peroxide flowing out from the ultraviolet oxidation device 5, in order to suppress the degradation of the ultrafiltration membrane of the downstream ultrafiltration membrane device 2, the ultraviolet irradiation amount in the ultraviolet oxidation device 5 is 0.05 ~ 0.2kWh / m ³ is preferred.

Hydrogen peroxide removal device (H ₂ O ₂ removal device) 6 is a device for decomposing and removing hydrogen peroxide in water, and examples thereof include a palladium-supported resin that decomposes and removes hydrogen peroxide by supporting a palladium (Pd) resin Device, or a reducing resin device filled with a reducing resin having a sulfite group and / or a hydrogen sulfite group on the surface. By providing the hydrogen peroxide removing device 6, since the concentration of hydrogen peroxide in water can be reduced, it is possible to suppress deterioration of the ultrafiltration membrane included in the ultrafiltration membrane device 2.

The degassing membrane device (MDG) 7 is a device that removes the secondary side of the reduced-pressure gas-permeable membrane by allowing only the dissolved gas flowing through the water flowing through the primary side to pass through the secondary side. As the degassing membrane device 7, specifically, commercially available products such as X-50, X40 manufactured by 3M Corporation, Separel manufactured by DIC Corporation, and the like can be used. The degassing membrane device 7 removes dissolved oxygen in the treated water obtained from the hydrogen peroxide removing device 6, and generates, for example, treated water having a dissolved oxygen concentration (DO) of 1 μg / L or less.

Non-regenerating mixed bed ion exchange resin device (Polisher) 8 is a mixed bed ion exchange resin with mixed cation exchange resin and anion exchange resin, which adsorbs and removes trace amounts of cation components and anion components in the treated water of the degassing membrane device 7. .

The non-regenerating mixed bed type ion exchange resin device 8 is a device which is accommodated by mixing a cation exchange resin and an anion exchange resin therein. Examples of the cation exchange resin used herein include strongly acidic cation exchange resins or weakly acidic cation exchange resins. Strongly acidic cation exchange resins are preferred. Examples of anion exchange resin systems include strong basic anion exchange resins. Resin, or weakly basic anion exchange resin, and strongly basic anion exchange resin are preferred. A mixed bed type ion exchange resin is preferably composed of a mixture of a strongly acidic cation exchange resin and a strongly basic anion exchange resin. As its commercially available product line, for example, N-Lite MBSP, MBGP manufactured by Nomura Micro Science, Japan can be used. Wait.

The ultrafiltration membrane device 2 processes the treated water of a non-regenerating mixed-bed ion exchange resin device 8 to generate permeate water and concentrated water. The removal rate of fine particles having a particle diameter of 20 nm or more in the ultrafiltration membrane device 2 is 99.8% or more, more preferably 99.95% or more, and more preferably 99.99% or more. According to this, through the ultrafiltration membrane device 2, fine particles that cause deterioration of the water quality of ultrapure water are almost removed. For example, the number of fine particles having a particle diameter of 20 nm or more can be 200 pcs./L or less, and 50 pcs./L or less. Through water. The ultrafiltration membrane device 2 is more capable of removing fine particles with a particle diameter of 10 nm or more by the above removal rate. Through this, the water quality of ultrapure water is further improved, and the number of fine particles with a particle diameter of 10 nm or more can be 200pcs./L Permeable water below and more than 50pcs./L. The permeated water generated in the ultrafiltration membrane device 2 is supplied to the subsequent filtration membrane device 3. The concentrated water system is discharged out of the system, or recycled to the front of the ultrapure water production system for reprocessing.

However, the ultrafiltration membrane device 2 is, as described above, the treated water of the non-regenerating mixed-bed ion exchange resin device 8 of FIG. 2, but is not limited to this. For example, water for removing coarse particles is, for example, In the ultrapure water production device, the treated water after the pre-treatment section is sufficient, and the pre-treated water, the primary treated water, the secondary treated water (including the case of circulating it), and the like can be used as the treated water. The ultrafiltration membrane device 2 has such a structure that the removal rate of the fine particles is as described above for the water to be treated. As this to-be-processed water, it is more preferable to use the treated water provided with the suspended substance removal device in the pre-processing part 10, or the treated water provided with the reverse osmosis membrane device in the primary pure water production part 11. The ultrafiltration membrane device 2 is preferably provided in the secondary pure water production section 13.

However, the removal rate of fine particles is, for example, the number of fine particles having a specific particle diameter or more permeating through the water when measuring the membrane to be measured, the water recovery rate is 95% or more, and the fine particles having a pressure of 0.1 MPa are passed through the water. The number of particles with a specific particle diameter in the feed water can be calculated as {1- (the number of particles with a specific particle diameter in the permeate water / the number of particles with a particle diameter greater than or equal to the particle diameter in the feed water)} × 100 (%). The removal rate was confirmed by mixing polystyrene latex (manufactured by Thermo Fisher, model 3020A with a nominal diameter of 20 nm) in ultrapure water and supplying water to a membrane device to be measured at a load of 500,000 pieces / ml.

As such an ultrafiltration membrane device 2 is easy to obtain a high particulate removal rate, an apparatus having an ultrafiltration membrane having a cutoff molecular weight of preferably 3000 to 10,000, and more preferably 4000 to 8000 is most preferable. However, the cut-off molecular weight of an ultrafiltration membrane can be measured as follows, for example. The removal rate of the labeled molecules was measured by passing a sample water containing a plurality of labeled molecules having known molecular weights and passing them through an ultrafiltration membrane to be measured. The measurement result of the obtained removal rate was plotted with respect to molecular weight, and the retention curve was made. From the cutoff curve, the removal rate is, for example, a molecular weight of 90% as the cutoff molecular weight of the film. As the labeling molecular system, dextran, polyethylene glycol (PEG), protein, and the like are used.

The ultrafiltration membranes included in the ultrafiltration membrane device 2 are, for example, an asymmetric membrane or a composite membrane. Polyurethane, polyolefin, polyester, polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), polyether Rhenium or polyamide is preferably used as the material. The shape of the film is a thin flat film, a spiral film, a tubular film, a hollow film, etc., but it is not limited to these. In order to obtain a high removal rate of fine particles, the structure made of polyfluorene is more preferable. However, the ultrafiltration membrane included in the ultrafiltration membrane device 2 may not have the acid-oxidizing agent resistance of the ultrafiltration membrane included in the filtration membrane device 3 described later.

The effective membrane area in the ultrafiltration membrane device 2 is preferably 5m ² to 60m ² , and more preferably 10m ² to 50m ² . 15m ² to 40m ² is more preferable. When the effective film area is in the above range, it is easy to suppress the deterioration of the film.

The water recovery rate in the ultrafiltration membrane device 2 is preferably 95% or more, and more preferably 99% or more. As a result, ultrapure water with highly-removed fine particles can be obtained, and the production efficiency of ultrapure water can be improved.

The treated water of the ultrafiltration membrane device 2, that is, the treated water of the non-renewable mixed-bed ion exchange resin device 8 is as described above. In the case where hydrogen peroxide is contained, the hydrogen peroxide concentration in the treated water is 0.1 to 3 μg / L. It is better, and 0.2 ~ 1μg / L is more preferable. When the concentration of hydrogen peroxide in the water to be treated of the ultrafiltration membrane device 2 is in the above range, it is easy to suppress the deterioration of the ultrafiltration membrane, and ultrapure water with highly fine particles removed for a longer period of time can be obtained.

The filtration membrane device 3 processes permeate water of the ultrafiltration membrane device 2 to generate permeate water and concentrated water. The filter membrane device 3 is provided with a filter membrane having oxidant resistance and a pore diameter of 2 to 40 nm. Examples of such a filtration membrane system include an ultrafiltration membrane (UF) or a precision filtration membrane (MF) configured using PVDF, PTFE, or the like as a material. Examples of the film shape system include a thin flat film, a spiral film, a tubular film, a hollow film, and the like, but are not limited thereto. However, the oxidation resistance of the filter membrane is, for example, after immersing it in 5% by mass of hydrogen peroxide water for 10 days, the change in the permeated water amount can be less than 5% before the test, or the change in its tensile strength is If the strength before the test is less than 5%, it is judged that an antioxidant is present. In addition, the film is not limited to a film judged to have oxidant resistance by the above-mentioned method, but a film labeled with hydrogen peroxide resistance or oxidation resistance may be used.

As described above, the particles in almost water are removed by the ultrafiltration membrane device 2, and the filtration membrane device 3 does not matter even if the particle removal rate as high as that of the ultrafiltration membrane device 2 is not achieved. Therefore, the removal rate of the fine particles having a particle diameter of 20 nm or more in the filtration membrane device 3 is preferably 40 to 95%, and more preferably 60 to 90%.

In the long-term production of ultrapure water through the ultrapure water production system 1, for example, the ultrafiltration membrane included in the ultrafiltration membrane device 2 is deteriorated by hydrogen peroxide flowing out from the ultraviolet oxidation device 5. In the case of waste materials. The waste material is, for example, about 20 to 100 nm. Therefore, the pore size of the filter membrane in the filter membrane device 3 is preferably 5 to 40 nm, and more preferably 10 to 30 nm. The pore size of the filter membrane can be judged by the nominal pore size. In addition, in the same method as the above-mentioned ultrafiltration membrane, the particle diameter can be measured using a known substance.

Since the above-mentioned fine particle removal rate is easily obtained, it is preferable that the pore diameter of the ultrafiltration membrane system in the filtration membrane device 3 is preferably 5 to 40 nm, and more preferably 10 to 30 nm.

The water recovery rate in the filtration membrane device 3 is preferably 80% or more, and more preferably 99% or more. As a result, ultrapure water with highly-removed fine particles can be obtained, and the production efficiency of ultrapure water can be improved.

As the permeated water of the filtration membrane device 3, ultrapure water having a particle diameter of 20 nm or more is preferably 500 pcs./L or less, and more preferably 200 pcs./L or less. Still more desirably, as the permeated water of the filtration membrane device 3, ultrapure water having a higher purity and a particle number of 20 nm or more and a particle size of 50 pcs./L or less can be obtained. In addition, the water quality of ultrapure water is, for example, a total organic carbon (TOC) concentration of 1 μg C / L or less and an impedance of 18 MΩ 以上 cm or more. The ultrapure water generated in the filtration membrane device 3 is supplied to a place of use (POU) for ultrapure water.

In the ultrapure water production system 1 of this embodiment, in the case where the ultrafiltration membrane of the ultrafiltration membrane device 2 does not have oxidant resistance, the ultrafiltration membrane is also provided through hydrogen peroxide flowing out of the ultraviolet oxidation device 5 described above. Deterioration occurs gradually, and waste material may be generated. However, the waste material from this ultrafiltration membrane is removed by the filtration membrane device 3 at the subsequent stage. Therefore, according to the ultrapure water production system 1 according to the present embodiment, even if the ultrafiltration membrane in the preceding stage is deteriorated, ultrapure water with highly removed particles can be obtained.

According to the ultrapure water production system and the ultrapure water production method according to the embodiments described above, it is possible to obtain highly purified ultrapure water with long-term removal of fine particles.

[Example]

Hereinafter, the present invention will be described in detail using examples. The present invention is not limited to the following examples.

(Example)
An ultrapure water production system having a secondary pure water production section similar to that shown in FIG. 2 was used. This secondary pure water production department is located downstream of the liquid tank that stores the primary pure water, and includes: a heat exchanger, an ultraviolet oxidizing device (manufactured by Japan Photo Science Corporation, JPW-2), and a Pd-carrying resin device (manufactured by LANXESS company) , Lewatit K7333), degassing membrane device (manufactured by 3M, X40 G451H), non-regenerating mixed bed type ion exchange device (N-Lite manufactured by Nomura Micro Science, Japan, MBSP filling 200L), ultrafiltration membrane device (Japan Asahi Kasei Corporation Production, OAT-6036HA (cut-off molecular weight (nominal): 4000, effective membrane area: 34m ² ) and filter membrane device (manufactured by Japan Entegris, Trinzik nominal pore size 15nm).

When primary pure water was supplied to the above-mentioned secondary pure water production department, and ultra-pure water was produced for 8 years, the change with time of the number of fine particles having a particle diameter of 0.4 μm or more of the permeated water of the filter membrane device is shown in Table 1. For the measurement of the number of particles, a direct microscopy method was used. For the measurement system, a Hitachi electron microscope was used.

In addition, when the number of years of water flow was 8 years, the number of fine particles was 500 pcs./L or less when the fine particles of UltraDI-20 manufactured by Particle Measuring Systems were used to measure the fine particles of 20 nm or more. In addition, Example 1 was retested, and the number of fine particles was measured with UDI-20 for one year, and the number of fine particles was 500 pcs./L or less.

(Comparative example)
In the ultrapure water production system used in the examples, for systems that differ only in the point of the filtration membrane device that does not have the latter of the ultrafiltration membrane device, the measurement was performed in the same manner as in the example, and primary pure water was supplied to produce ultrapure water for 8 years. In the case of water, the number of fine particles having a particle diameter of 0.4 μm or more permeated in the ultrafiltration membrane device changes over time. The results are shown in Table 2.

In addition, when the number of years of water flow was 8 years, the number of particles was measured at 1000 pcs./L when UltraDI-20, a particle meter manufactured by Particle Measuring Systems, was used to measure particles above 20 nm.

As shown in Tables 1 and 2, in the ultrapure water manufacturing system of the embodiment in which the filter membrane device is installed in the latter stage of the ultrafiltration membrane device, after 8 years, the number of particles having a particle diameter of 0.4 μm or more is 0.5 pcs./ L or less, and from the same situation as in the initial stage when the number of fine particles of 20 nm or more passed through UltraDI-20 is compared to the configuration of a comparative example without a filter membrane device, it is understood that ultrapure water with long-term reduced fine particles can be obtained.

1‧‧‧ Ultra-pure water manufacturing system

2‧‧‧ ultrafiltration membrane device

3‧‧‧filtration membrane device

4‧‧‧Heat exchanger (HEX)

5‧‧‧ultraviolet oxidation device (TOC-UV)

6‧‧‧ Hydrogen peroxide removal device

7‧‧‧ Degassing membrane device (MDG)

8‧‧‧ Non-regenerating mixed bed ion exchange resin device (Polisher)

10‧‧‧Pre-treatment Department

11‧‧‧Primary Pure Water Manufacturing Department

12‧‧‧ liquid tank

13‧‧‧Second Pure Water Manufacturing Department

FIG. 1 is a block diagram showing an ultrapure water production system according to the embodiment.

Fig. 2 is a block diagram showing a secondary pure water production department according to the embodiment.

Claims (8)

An ultrapure water manufacturing system includes an ultrafiltration membrane device and a filtration membrane device connected to the ultrafiltration membrane in series. The treated water is sequentially processed in the ultrafiltration membrane device and the filtration membrane device to produce an ultrafiltration water. Ultra-pure water manufacturing system for pure water, characterized by The removal rate of the fine particles having a particle diameter of 20 nm or more in the ultrafiltration membrane device is 99.8% or more. The filter membrane device includes a filter membrane having a pore diameter of 2 to 40 nm, which is resistant to oxidants. For example, the ultrapure water production system described in the first item of the patent application range, wherein the ultrafiltration membrane device has an ultrafiltration membrane with a molecular weight cut-off of 3000 to 10,000. For example, the ultrapure water production system described in the first or second item of the patent application scope, wherein the ultrafiltration membrane device has an ultrafiltration membrane using polyfluorene, polyvinylidene fluoride, or polytetrafluoroethylene as a material. For example, the ultrapure water production system described in any one of the scope of the patent application, and the third, wherein the aforementioned filter membrane device has a filter membrane using polyvinylidene fluoride or polytetrafluoroethylene as a material. For example, the ultrapure water production system described in any one of the scope of the application for the item 1 to 4, wherein the ultrafiltration membrane device has a hydrogen peroxide removal device and flows over the ultrafiltration membrane device to process the hydrogen peroxide removal device. As the water to be treated, water can be sequentially processed in the ultrafiltration membrane device and the filtration membrane device. For example, the ultrapure water production system described in any one of the scope of the patent application, which is described in any one of items 1 to 5, wherein the ultrafiltration membrane device flows above the ultrafiltration membrane device, and according to this, an ultraviolet oxidation device, a hydrogen peroxide removal device, a deaeration membrane device, Non-regenerating mixed-bed ion exchange resin devices are sequentially provided, Those who use the treated water of the aforementioned non-regenerating mixed-bed ion exchange resin device as the treated water can be sequentially processed in the ultrafiltration membrane device and the filtration membrane device. A method for producing ultrapure water, characterized in that water to be treated is passed through an ultrafiltration membrane device, and particles with a particle diameter of 20nm or more are processed with a removal rate of 99.8% or more, The treated water of the aforementioned ultrafiltration membrane device is passed through a filter membrane device having a filtration membrane having a pore diameter of 2 to 40 nm, which is resistant to oxidants, and is treated. For example, the method for producing ultrapure water described in item 7 of the scope of the patent application, wherein the water to be treated of the ultrafiltration membrane device contains hydrogen peroxide in an amount of 0.1 to 3 μg / L.