TWI802696B - Ultrafiltration membrane module and method for producing ultrapure water using the ultrafiltration membrane module - Google Patents

Abstract

The object of the present invention is to provide an ultra-filtration membrane module and a method for producing ultra-pure water that can significantly reduce the concentration of trace ion components in ultra-pure water, especially warm ultra-pure water. The solution of the present invention is an ultrafiltration membrane module, which is composed of: a plurality of hollow fiber membranes (1) made of ultrafiltration membranes, and a cylindrical box ( 2) The formed ultrafiltration membrane module (10) is characterized in that the cylindrical box (2) has the first nozzle (2a) and the second nozzle (2b), and the third nozzle (6a) and the fourth nozzle ( 6b), and a pair of fixing parts (3a, 3b), the first nozzle (2a) and the second nozzle (2b) are arranged on the outer peripheral surface of the tubular box (2) at a distance from each other in the axial direction, Introduce the water to be treated and let the concentrated water flow out. The third nozzle (6a) and the fourth nozzle (6b) are arranged at both ends of the cylindrical box to respectively let the permeate and discharge water through the hollow fiber membrane (1) The water flows out, and the pair of fixing parts (3a, 3b) fix the plurality of hollow fiber membranes (1) in a predetermined arrangement, and seal the cylindrical case (2).

Description

Ultrafiltration membrane module and method for producing ultrapure water using the ultrafiltration membrane module

The invention relates to an ultrafiltration membrane module and an ultrapure water manufacturing method using the ultrafiltration membrane module.

Conventionally, ultrapure water used in the manufacture of electronic and electrical components such as semiconductors and display elements was manufactured using an ultrapure water manufacturing system. Ultra-pure water manufacturing system, for example, to remove suspended substances in raw water, to obtain pre-treated water pre-treatment section, and to use reverse osmosis membrane device or ion exchange device to remove total organic carbon (TOC) components or ion components in pre-treated water The primary pure water production department removes and produces primary pure water, and the secondary pure water production department removes extremely small amounts of impurities in the primary pure water to produce ultrapure water. As raw water, city water, well water, ground water, industrial water, etc. are used. In addition, used ultrapure water (hereinafter referred to as "recycled water") recovered at the point of use (Use point: POU) of ultrapure water may also be used as raw water.

In the secondary pure water manufacturing department, the primary pure water is highly treated to produce ultrapure water by means of ultraviolet oxidation devices, ion exchange pure water devices, and ultrafiltration membrane (UF) devices. The ultrafiltration membrane device is arranged near the last stage of the secondary pure water production department to remove fine particles produced by ion exchange resins and the like.

This ultra-filtration membrane device is an ultra-filtration membrane module that accommodates yarn bundles of hollow fiber-shaped ultra-filtration membranes in a cylindrical box, and is composed of multiple units in response to the amount of water to be collected. As an ultrafiltration membrane module, it is common to supply raw water on the outside of the hollow fiber membrane with external pressure. There are ultrafiltration membrane modules that collect water from both ends and collect water from both ends, or from one end. A piece-end water collection type ultrafiltration membrane module that supplies treated water and collects filtered water from the other end (for example, refer to Patent Documents 1 and 2).

In the ultrafiltration membrane module, there are components of the medicine used in the manufacture of the ultrafiltration membrane, or the components of the adhesive or potting agent used when the ultrafiltration membrane is assembled into the module, which dissolve and contaminate during use Permeation of water. Therefore, a method of manufacturing an ultrafiltration membrane module that is generally suitable for cleaning the ultrafiltration membrane module before the production of ultrapure water is proposed for the purpose of easily cleaning the above-mentioned pollutants (for example, refer to Patent Document 3) . Also, as a potting agent for subsequent sealing of an ultrafiltration membrane, a material with less elution of organic substances has been proposed (for example, refer to Patent Document 4). [Prior Art Literature] [Patent Document]

[Patent Document 1] Japanese Patent Application Laid-Open No. 7-96152 [Patent Document 2] International Publication No. 2012/043679 [Patent Document 3] Japanese Patent Laid-Open No. 2001-129366 [Patent Document 4] Japanese Patent Laid-Open No. 2017-136548

[Problem to be solved by the invention]

However, in recent years, along with miniaturization of semiconductor integrated circuits, etc., objects to be cleaned with ultrapure water (substances to be removed by cleaning) have also been diversified, and objects to be cleaned that are difficult to clean have also increased. Therefore, in the cleaning of semiconductors, in order to improve the detergency, warm ultrapure water, which is heated to ultrapure water, etc. are also used. In addition, with the demand for high-definition purification of the washed objects, the requirements for the water quality of ultra-pure water are gradually becoming stricter. In this way, the present inventors found that very trace amounts of ion components (chloride ions (Cl ⁻ ), etc.) remained in the ultrapure water supplied from the secondary pure water production unit of the ultrapure water production apparatus. In particular, it is known that the trace ion components in the warm ultrapure water flowing through the secondary pure water manufacturing department prevent the improvement of the ultrapure water quality. Furthermore, it was found that this trace ion component is a component that elutes the pharmaceutical used in the manufacture of the ultrafiltration membrane, or a component of the adhesive or potting agent used when the ultrafiltration membrane is assembled into a module. However, near the manufacturing conditions of warm ultrapure water (for example, 80° C.), ultrafiltration membrane modules that do not produce leached substances or hardly produce leached substances have not yet been distributed in the market. Therefore, the development of an ultrafiltration membrane module that reduces the generation of dissolved substances is sought.

The present invention is completed based on the above findings, and aims to provide an ultra-filtration membrane module that can significantly reduce the concentration of trace ionic components in ultra-pure water, especially warm ultra-pure water, and an ultra-pure water manufacturing method using the same. [Means to solve the problem]

The ultrafiltration membrane module of the present invention is composed of: a plurality of hollow fiber membranes composed of ultrafiltration membranes, and an ultrafiltration membrane module composed of a cylindrical box for accommodating the aforementioned plurality of hollow fiber membranes. It is characterized in that the above-mentioned cylindrical box has a first nozzle and a second nozzle, a third nozzle and a fourth nozzle, and a pair of fixing parts, and the first nozzle and the second nozzle are attached to the outer peripheral surface of the aforementioned cylindrical box. The axial direction is spaced apart from each other, the third nozzle and the fourth nozzle are arranged at both ends of the aforementioned cylindrical box, and the pair of fixing parts is to connect the aforementioned plurality of hollow fiber membranes to the aforementioned plurality of hollow fibers. The opening ends of the film are respectively directed to the two ends of the aforementioned cylindrical case, fixed along the axial direction of the aforementioned cylindrical case, and between the end of one side of the aforementioned cylindrical case and the aforementioned first nozzle and the aforementioned cylindrical case Each position between the end of the other side of the box and the second nozzle seals the aforementioned cylindrical box. The aforementioned first nozzle is a treated water inlet pipe that introduces the treated water. The concentrated water outflow pipe through which the concentrated water from the hollow fiber membrane flows out, the third nozzle is the permeate water outflow pipe through which the permeate water passing through the hollow fiber membrane flows out, and the fourth nozzle is the outflow pipe through which the discharge water through the hollow fiber membrane flows out Drain the water out of the tube.

In the ultrafiltration membrane module of the present invention, preferably, the permeated water outflow pipe is arranged closer to the concentrated water outflow pipe than the treated water inlet pipe.

In the ultrafiltration membrane module of the present invention, preferably, the aforementioned fixing part is made of epoxy resin.

In the ultrafiltration membrane module of the present invention, it is preferably the value of the ratio of the outflow from the aforementioned permeate water outflow pipe to the outflow from the aforementioned discharge water outflow pipe (from the outflow of the permeate water outflow pipe/from the discharge water The outflow of the outflow pipe) is 90/10 or more and 99/1 or less.

The ultrapure water production method of the present invention is composed of: a plurality of hollow fiber membranes composed of ultrafiltration membranes, and an ultrafiltration membrane module composed of a cylindrical box for accommodating the plurality of hollow fiber membranes. It is characterized in that the above-mentioned cylindrical box is provided with a first nozzle and a second nozzle, a third nozzle and a fourth nozzle, and an ultrafiltration module with a pair of fixing parts, the first nozzle and the second nozzle are attached to the outer peripheral surface thereof, The axial direction of the aforementioned cylindrical box is arranged at a distance from each other, the third nozzle and the fourth nozzle are arranged at both ends of the aforementioned cylindrical box, and the pair of fixing parts are used to hold the plurality of hollow fiber membranes in The opening ends of the plurality of hollow fiber membranes are fixed along the axial direction of the cylindrical case in such a way that the opening ends of the plurality of hollow fiber membranes point to the two ends of the aforementioned cylindrical case respectively, and the end of one side of the aforementioned cylindrical case is connected to the first Each position between the nozzles and between the end of the other side of the aforementioned cylindrical box and the aforementioned second nozzle seals the aforementioned cylindrical box, and the water to be treated is introduced into the aforementioned ultrafiltration membrane module from the aforementioned first nozzle. The second nozzle discharges the concentrated water that does not pass through the hollow fiber membrane, the third nozzle of the cylindrical case discharges the permeated water that has passed through the hollow fiber membrane, and the fourth nozzle discharges the permeated water that has passed through the hollow fiber membrane. Water flows out, and the aforementioned permeated water can be used as ultrapure water.

In the ultrapure water production method of the present invention, it is preferable that the concentration of chloride ions (Cl ^- ) in the water to be treated is not less than 0.01 μg/L and not more than 2 μg/L (as Cl).

In the ultrapure water production method of the present invention, it is preferable that the chloride ion (Cl ^- ) concentration in the water to be treated is 1 ng/L or less (as Cl).

In the ultrapure water production method of the present invention, it is preferable that the chloride ion (Cl ⁻ ) concentration in the permeated water of the aforementioned ultrafiltration membrane module is 5 ng/L or less (as Cl).

The symbol "~" in this specification represents the numerical range which includes the numerical value of both sides. [Invention effect]

According to the ultrafiltration membrane module of the present invention, the concentration of trace ion components can be significantly reduced in the case of treating the treated water to produce ultrapure water, especially warm ultrapure water. According to the ultrapure water production method of the present invention, ultrapure water with significantly reduced trace ion components can be obtained, especially ultrapure water suitable for warm ultrapure water.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. (first embodiment) The ultrafiltration membrane module 10 of the present embodiment shown in Fig. 1 is equipped with: a plurality of hollow fiber membranes 1, a cylindrical box 2 for accommodating the hollow fiber membranes 1, and fixing both ends of the hollow fiber membranes 1 A pair of fixing parts 3a, 3b inside the cylindrical case. The ultrafiltration membrane module 10 has pipe connection caps 60a, 60b with nozzles 6a, 6b at both ends of the cylindrical box 2, respectively. Grooves are respectively formed in the contact portions 61a and 61b of the ends of the tubular case 2 with the pipe connection cap, and the pipe connection cap is fixed to a part of the covered pipe connection cap by an О ring (not shown) arranged in the groove. A nut (not shown) at the end of the cylindrical case 2 is mounted on the cylindrical case 2 .

The cylindrical case 2 is equipped with nozzle 2a, 2b on the outer peripheral surface. The nozzles 2a and 2b are arranged at a distance from each other in the axial direction of the cylindrical case 2 on the outer peripheral surface of the cylindrical case 2 . Also, in FIG. 1, the nozzle 6a and the nozzle 6b may be arranged in opposite positions, but as shown in FIG. 1, it is preferable that the nozzle 6b is arranged closer to the nozzle 2b than the nozzle 2a.

The hollow fiber membrane 1 is, for example, a yarn bundle in which a plurality of hollow fiber membranes are collected into one bundle. Alternatively, the hollow fiber membrane 1 is a part of the plurality of hollow fiber membranes accommodated in the cylindrical case 2 divided into concentrated small bundles, and the small bundles may be collected. The yarn bundles or small bundles of the hollow fiber membrane 1 may be entirely covered with a polypropylene net or non-woven fabric. By concentrating the hollow fiber membranes into yarn bundles and placing them in the cylindrical case 2, a portion not filled with the hollow fiber membranes 1 is formed between the hollow fiber membranes 1 in the cylindrical case 2 and the inner peripheral surface of the cylindrical case 2 (the part with low membrane filling density), thereby reducing the resistance of the water flowing outside the hollow fiber membrane 1, and achieving higher water permeability of the module.

As the hollow fiber membrane 1, an ultrafiltration membrane is used. The fractional molecular weight of the ultrafiltration membrane is preferably 4000-6000, the effective membrane area is preferably 10m ² -35m ² , and the design operation differential pressure is preferably 0.1MPa-0.4MPa. In addition, the microparticle removal performance of the ultrafiltration membrane is preferably such that the removal rate of microparticles with a particle size of 20 nm or more is above 65%. Furthermore, the design operating differential pressure is the range from the maximum value to the operating differential pressure (the difference between the pressure of the permeated water and the pressure of the supplied water) at which the impurity blocking rate of the ultrafiltration membrane reaches 90% of the maximum value. The design operating differential pressure is used as the standard operating pressure of the ultrafiltration membrane, etc., which can be the value published by the manufacturer.

The material of the hollow fiber membrane can be appropriately selected according to the application, for example, it can be selected from polyethylene, polypropylene, polypropylene, polyether fluoride, polyvinylidene fluoride, polyvinyl alcohol, cellulose acetate, and polyacrylonitrile.

The inner diameter of the hollow fiber membrane is preferably from 0.50 to 1.0 mm, particularly preferably from 0.70 to 0.85 mm.

The cylindrical case 2 is composed of a cylindrical member having openings at both ends. The cylindrical case 2 has the nozzles 2a, 2b provided in the vicinity of the interfaces Fa, Fb of the fixed parts 3a, 3b. The interface of the fixed portion means the surface of the fixed portion on the side where the hollow fiber membranes 1 are accommodated in the cylindrical case 2 . The material of the cylindrical box 2 can be appropriately selected from metal and plastic due to the application. From the viewpoint of ease of processing and light weight, it is preferable that the tubular case 2 is formed of plastics. The material of the cylindrical case 2 includes, for example, polyethylene, polypropylene, polypropylene, polyether fluoride, polyvinylidene fluoride, acrylonitrile-butadiene-styrene copolymer resin (ABS resin), vinyl chloride resin, etc. . Furthermore, the nozzles respectively provided near the interfaces Fa and Fb do not have to be one after the other, and a plurality of nozzles may be provided respectively near the interfaces Fa and Fb.

The size of the cylindrical box 2 can also be appropriately selected according to the amount of water to be treated. As an example, the outer diameter is preferably 140-200 mm, and the length is 700-1400 mm, and the outer diameter is 160-180 mm, and the length is 800 mm. ~1200mm. When the cylindrical box 2 of this size range is used, a high module water permeability and the highest module water permeability can be realized. Moreover, if it is the above-mentioned size, since the ultrafiltration membrane module 10 can be made into a weight that can be carried by one person, there is an advantage that the handling property is very good. Still, the so-called "outer diameter" of the cylindrical box 2 refers to the outer diameter of the cylinder in the filtration area at the center of the ultrafiltration membrane module 10. The so-called "length" of the tubular case 2 means the distance between the two ends of the hollow fiber membrane.

The fixing parts 3 a and 3 b are attached to both ends of the hollow fiber membrane 1 in the cylindrical case 2 , and seal the outer surfaces of the hollow fiber membranes 1 and the gap between the outer surface and the inner surface of the cylindrical case 2 . The fixing parts 3a, 3b fix the hollow fiber membranes 1 along the axial direction (longitudinal direction) of the cylindrical case 2, so that the opening ends of the hollow parts of the hollow fiber membranes 1 are exposed to both ends of the cylindrical case 2, respectively. side. During water treatment, permeated water flows out from the opening.

As a material of the fixing parts 3a and 3b, a thermosetting resin such as epoxy resin or urethane resin is used. As the material of the fixing parts 3a, 3b, epoxy resin is preferable because it is less eluted. Examples of epoxy resins include bisphenol A-type epoxy resins, bisphenol F-type epoxy resins, biphenyl-type epoxy resins, naphthalene-type epoxy resins, phenol novolak-type epoxy resins, bisphenol-type epoxy resins, Phenol A novolac type epoxy resin, parahydroxymethane type epoxy resin, tetraphenol ethane type epoxy resin, tetraglycidyl diaminodiphenylmethane type epoxy resin, aminophenol type epoxy resin Epoxy resin, aniline-type epoxy resin, benzylamine-type epoxy resin, xylenediamine-type epoxy resin, etc.

The material of the fixing parts 3 a and 3 b is selected according to the material of the hollow fiber membrane 1 , the adhesion to the hollow fiber membrane 1 , the strength of the hollow fiber membrane 1 , and the like. As the material of the fixing parts 3a and 3b, one with less eluted components is preferable. Specifically, as an example of this material, it is preferable to use a hollow fiber membrane module with an effective membrane area of ^about 34m2, an outer diameter of the module of 160-180mm, and a length of 800-1200mm. In the state of use, when in contact with warm pure water of about 70-80°C, the elution amount of chloride ions in the permeated water is 10 ng/L or less, preferably 6 ng/L or less. Furthermore, by using a material that suppresses elution of organic components as the material of the fixing portions 3a, 3b, the amount of elution of organic components can be suppressed.

The ultrafiltration membrane module 10 of this embodiment can have a pair of rectifying tubes respectively extending from the positions of the interfaces Fa and Fb of the fixing parts 3a and 3b toward the center of the module 10 . If the rectifying cylinders respectively surrounding the fixed parts 3a, 3b and both ends of the hollow fiber membrane 1 are provided, damage to the hollow fiber membrane near the interface Fa, Fb can be effectively prevented.

The nozzles 2a, 2b and the nozzles 6a, 6b of the ultrafiltration membrane module 10 of the present embodiment are connected to pipes to supply treated water, collect permeated water, and discharge concentrated water. In the ultrafiltration membrane module 10, for example, the nozzle 2a is defined as a water-to-be-treated inlet pipe (first nozzle), and the nozzle 2b is defined as a concentrated water outflow pipe (second nozzle). Also, the nozzle 6a is defined as a discharge water outflow pipe (fourth nozzle), and the nozzle 6b is defined as a permeated water outflow pipe (third nozzle). For example, the nozzle 2b (concentrated water outflow pipe) is connected to the concentrated water pipe 101 inserted into the variable opening valve V1, and the nozzle 6a (discharge water outflow pipe) is connected to the discharge water pipe 102 inserted into the variable opening valve V2. Further, the treated water pipe 103 is connected to the nozzle 2a (the water to be treated inlet pipe), and the permeated water pipe 104 is connected to the nozzle 6b (the permeated water outflow pipe).

The water to be treated is introduced into the ultrafiltration membrane module 10 from the nozzle 2a, and is filtered during the process of flowing from the outside of the hollow fiber membrane to the inside, the concentrated water flows out from the nozzle 2b, and the permeated water flows out from the permeated water outflow pipe, namely the nozzle 6b. Moreover, part of the permeated water flows out from the nozzle 6a which is a discharge water outflow pipe as discharge water.

As the water to be treated, water from which ionic components, non-ionic components, dissolved gases and fine particles have been removed from raw water by ion exchange treatment, degassing treatment, ultraviolet oxidation treatment, ultrafiltration, precision filtration, etc. can be used. Such water to be treated is generally called primary pure water or pure water, and water with a TOC (total organic carbon) concentration of 5 μgC/L or less and a specific resistivity of 17 MΩ･cm or more can be cited. In addition, the concentration of ion components in the water to be treated, such as chloride ion (Cl ^- ) concentration, is 0.01 μg/L to 2 μg/L (as Cl, the same below), preferably 0.01 μg/L to 0.1 μg/L.

The temperature of the water to be treated is preferably not less than 10°C and not more than 90°C, more preferably not less than 20°C and not more than 80°C. As the water to be treated, when warm water with high temperature is used, since there is a tendency to increase the leached matter from the fixed parts 3a and 3b, by setting the above temperature range, it is easy to obtain a great effect on the suppression of leached matter.

According to the ultrafiltration membrane module 10 of the above-mentioned embodiment, the permeated water with significantly reduced ion components is obtained from the nozzle 6b. This is considered to be for the following reasons. In the ultrafiltration membrane module with water collection at both ends, the permeated water generated in the ultrafiltration membrane module flows out from the nozzles 6a and 6b through contact with the fixing parts 3a and 3b arranged near both ends of the cylindrical box . It is presumed that when the permeated water comes into contact with the fixed parts 3a and 3b, the eluted components from the materials of the fixed parts 3a and 3b are mixed into the permeated water to cause contamination. Specifically, this eluted component is an ion component such as an organic component or a chloride ion (Cl ⁻ ). There is a tendency that the higher the water temperature, the larger the eluted components.

On the other hand, in the ultrafiltration membrane module 10 of this embodiment, a part of the permeated water generated in the ultrafiltration membrane module flows out from the nozzle 6b and is used as ultrapure water. At this time, the permeated water comes into contact with the fixing portion 3b provided near the end portion on one side of the cylindrical case 2 . The amount of the eluted component of the material from the fixed portion 3b is ideally half the amount of the eluted component of the material from the fixed portion 3a, 3b. The remainder of the permeated water generated in the ultrafiltration membrane module flows out from the nozzle 6a as discharge water not used as ultrapure water. Thereby, the incorporation of dissolved components into permeated water is reduced.

In fact, even if the outflows from the nozzle 6a and the nozzle 6b are equal, the amounts of eluted components in the discharged water and the permeated water flowing out from both are not necessarily equal. For example, in addition to the flow rate or water recovery rate of the treated water, in response to the size of the ultrafiltration membrane module 10, etc., by adjusting the opening of the valve V2 inserted into the discharge pipe 102, the outflow from the nozzle 6a and the nozzle 6b can be adjusted. The ratio can reduce the amount of migration of the eluted components from the materials of the fixed parts 3a, 3b in the permeated water. According to the ultrafiltration membrane module 10 of the above structure, for example, even if the water to be treated is passed through at a temperature of 70°C to 80°C, the concentration of chloride ions (Cl ^- ) from the nozzle 6b can be reduced to 5ng/L or less. It is better to obtain permeated water below 1ng as ultrapure water. Also, the concentration of chloride ions in permeated water is determined by the quantitative lower limit of the measuring equipment, but it is considered to be as low as about 0.1 ng.

For example, the outflow from the nozzle 6a (discharge water outflow pipe) and the nozzle 6b (permeated water outflow pipe), as the outflow from the nozzle 6b L _t (cm ³ /h) relative to the outflow from the nozzle 6a L _c ( The ratio L _t /L _c in cm ³ /h) is preferably 90/10-99/1, more preferably 95/5-98/2. The value of the outflow ratio L _t /L _c can be adjusted by adjusting the opening of the valve V2. Also, the ratio of the outflow amount L _t /L _c can be adjusted by reducing the inner diameter of the drain water outflow pipe to be smaller than the inner diameter of the permeated water outflow pipe. When _Lt / _Lc is within the above-mentioned range, it is easy to reduce the amount of eluted ion components in the permeated water.

In the ultrafiltration membrane module 10 of this embodiment, the water recovery rate is preferably above 90%, more preferably above 95%. The operating differential pressure of the ultrafiltration membrane module 10 is preferably 0.1 MPa-0.4 MPa. Thereby, since the stagnation of water in the ultrafiltration membrane module can be reduced, the amount of migration of dissolved components in the permeated water can be reduced.

Next, an ultrapure water production system 100 using the ultrafiltration membrane module of the above-mentioned embodiment will be described with reference to FIG. 2 .

The ultrapure water production system 100 shown in FIG. 2 has a pretreatment unit 11 , a primary pure water production unit 12 and a secondary pure water production unit 13 . A storage tank 14 is connected between the primary pure water production unit 12 and the secondary pure water production unit 13 .

The pretreatment unit 11 removes suspended substances in the raw water, generates pretreated water, and supplies the pretreated water to the primary pure water production unit 12 . The pretreatment unit 11 is constituted by appropriately selecting, for example, a sand filter device and a precision filter device for removing suspended substances in raw water, and may further include a heat exchanger for temperature adjustment of raw water if necessary. Still, the pretreatment unit 11 can be omitted depending on the water quality of the raw water.

Raw water is, for example, urban water, well water, ground water, industrial water, used in semiconductor manufacturing plants, etc., and is recycled as pre-treated water (recycled water).

Primary pure water production department 12 is a proper combination of reverse osmosis membrane device, degassing device (decarbonation, vacuum degassing device, degassing membrane device, etc.), ion exchange device (cation exchange resin device, anion exchange resin device, mixed bed type ion exchange resin device, etc., electrical deionization device, etc.), ultraviolet oxidizing device at least one. The primary pure water production unit 12 removes ionic components, non-ionic components, and dissolved gases from the pretreated water to produce primary pure water, and supplies the primary pure water to the storage tank 14 . Primary pure water such as total organic carbon (TOC) concentration below 5μgC/L, resistivity above 17MΩ･cm.

As the primary pure water production unit, for example, strong basic anion exchange resin equipment, 2B3T type equipment (strongly acidic cation exchange resin equipment, decarbonation tower, basic anion exchange equipment), reverse osmosis membrane equipment, ultraviolet oxidation equipment, A mixed-bed ion exchange resin device and a degassing membrane device are sequentially equipped.

The storage tank 14 stores primary pure water. The pump P supplies the necessary amount to the secondary pure water production unit 13 .

Secondary pure water manufacturing unit 13 removes trace impurities in primary pure water to produce ultrapure water. As shown in Figure 2, the secondary pure water production unit 13 is equipped with a heat exchanger (HEX) 34, an ultraviolet oxidizing device (TOC-UV) 35, a hydrogen peroxide removing device ( _H2 O ₂ removal device) 36, degassing membrane device (MDG) 37, non-regenerative mixed bed ion exchange resin device (Polisher) 38. Furthermore, the secondary pure water production unit 13 does not necessarily need to be equipped with the above-mentioned devices, and the above-mentioned devices may be used in combination if necessary.

The pump P pressurizes the primary pure water supplied from the storage tank 14 and supplies it to the heat exchanger (HEX) 34 . The heat exchanger 34 performs temperature adjustment of the primary pure water supplied from the storage tank 14 as necessary. The temperature of the primary pure water adjusted in the heat exchanger 34 is preferably not less than 20°C and not more than 30°C, more preferably not less than 22°C and not more than 25°C.

The ultraviolet oxidizing device (TOC-UV) 35 is used to irradiate ultraviolet rays on the temperature-regulated primary pure water in the heat exchanger 34 to decompose and remove trace organic matter in the water. The ultraviolet oxidizing device 35 has, for example, an ultraviolet lamp, and generates ultraviolet rays having a wavelength near 185 nm. The ultraviolet ray oxidizing device 35 can further generate ultraviolet rays with a wavelength near 254 nm. When water is irradiated with ultraviolet rays in the ultraviolet oxidizing device 35, the ultraviolet rays do not decompose water to generate OH radicals, and the OH radicals oxidize and decompose organic matter in the water. In order to suppress the deterioration of the ultrafiltration membrane of the downstream ultrafiltration membrane device 30, the amount of ultraviolet irradiation in the ultraviolet oxidation device 35 is preferably 0.05-0.2 kWh/m ³ .

The hydrogen peroxide removal device (H ₂ O ₂ removal device) 36 is a device for decomposing and removing hydrogen peroxide in water, for example, there is a palladium-carrying resin device for decomposing and removing hydrogen peroxide by palladium (Pd) carrying resin, or Reducing resin device filled with reducing resin having sulfite group and/or bisulfite group on the surface, etc. By providing the hydrogen peroxide removal device 36, since the hydrogen peroxide in water can be reduced, deterioration of the ultrafiltration membrane device 30 and the second ultrafiltration membrane device 40 described later can be suppressed.

The degassing membrane device (MDG) 37 is the secondary side of the decompression gas permeable membrane, and only the dissolved gas in the water flowing through the primary side is removed through the secondary side. As the degassing membrane device 37 , specifically, commercially available products such as X-50 and X40 manufactured by 3M Corporation and Separel manufactured by DIC Corporation can be used. The degassing membrane device 37 removes dissolved oxygen in the treated water of the hydrogen peroxide removing device 36, for example, generates treated water with a dissolved oxygen concentration (DO) of 1 μg/L or less.

Non-regenerative mixed bed ion exchange resin device (Polisher) 38 is a mixed bed ion exchange resin with mixed cation exchange resin and anion exchange resin, which absorbs and removes trace amounts of cationic components and anionic components in the treated water of degassing membrane device 37 .

As the cation exchange resin included in the non-regenerative mixed bed ion exchange resin device 38, strong acid cation exchange resin or weak acid cation exchange resin can be mentioned, and as anion exchange resin, strong base anion exchange resin or weak base can be mentioned. anion exchange resin. As commercially available mixed bed ion exchange resins, for example, N-Lite MBSP and MBGP manufactured by Nomura Micro Science can be used.

The ultrafiltration membrane device 30 is equipped with the ultrafiltration membrane module 10 of the above-mentioned embodiment. The ultrafiltration membrane device 30 treats the treated water of the non-regenerative mixed-bed ion exchange resin device 38 to generate permeated water, concentrated water and discharged water. The ultrafiltration membrane device 30 preferably has a removal rate of at least 99.8%, more preferably at least 99.95%, and even more preferably at least 99.99% of particles with a particle size of 20 nm or more. Thereby, by using the ultrafiltration membrane device 30, most of the microparticles that become the cause of the deterioration of the ultrapure water quality are removed, for example, the number of microparticles with a particle diameter of 50nm or more can be obtained to be 500pcs./L or less, and further 200pcs./L The following pass through water. In the ultrafiltration membrane device 30 , the generated permeated water is supplied to a use point (Use point: POU) 50 of ultrapure water. The concentrated water is discharged out of the system, or is circulated before the ultrapure water production system 100 for reprocessing.

In the ultrapure water production system of this embodiment, since chlorine is adsorbed and removed by the non-regenerative mixed-bed ion exchange resin device 38, the concentration of chloride ions in the water supplied to the ultrafiltration membrane device 30 can be, for example, 5 ng/L or less. .

According to the ultrapure water production system 100 described above, since the ultrafiltration membrane device 30 equipped with the ultrafiltration membrane module 10 of the present embodiment is arranged downstream of the secondary pure water production section 13, the ultrafiltration from the ultrafiltration is significantly suppressed. Dissolution of pollutants from membrane modules. Therefore, ultrapure water with significantly reduced ionic components such as chloride ions can be obtained.

Also, as shown in FIG. 3, the ultrafiltration membrane device 30 of the ultrapure water manufacturing system 100 shown in FIG. The second ultrafiltration membrane device (UF2) 40 of group 10 is arranged sequentially. In this case, for example, a branch pipe is connected to the permeated water outflow pipe of the ultrafiltration membrane device 30, and the second heat exchanger 41 and the second ultrafiltration membrane device 40 are arranged in the path of the branch pipe, so that the ultrafiltration membrane device 40 can be used for ultrafiltration. Part of the permeated water (ultrapure water) obtained by the membrane device 30 flows through the second heat exchanger 41 and the second ultrafiltration membrane device (UF2) 40 sequentially.

When using the second heat exchanger 41 and the second ultrafiltration membrane device 40, the second heat exchanger 41 preferably heats the treated water of the ultrafiltration membrane device 30 to 70-90°C and supplies it to the second ultrafiltration membrane device 40. As the second ultrafiltration membrane device 40, a device having the same specifications as the above-mentioned ultrafiltration membrane device 30 may be used, or a device having a different specification may be used. Thereby, for example, warm ultrapure water heated to 70-90°C can be obtained. In the second ultrafiltration membrane device 40 , the generated permeated water is supplied to a point of use (Use point: POU) 51 of warm ultrapure water. In this case, when the method of the present invention is not used, although the amount of dissolved components (pollutants) from the ultrafiltration membrane module is easily increased by warm ultrapure water, but due to the use of the ultrafiltration membrane module of the embodiment, it is possible to obtain The so-called great effect of ultrapure water with significantly reduced ionic components such as chloride ions. Still, when configuring the second ultrafiltration membrane device 40, if the ultrafiltration membrane module of the above-mentioned embodiment is used in the second ultrafiltration membrane device 40, the first ultrafiltration membrane device 30 can use the ultrafiltration membrane module of the above-mentioned embodiment , You can also use the conventional ultra-filtration membrane module with both ends of the water collection type.

The concentration of chloride ions in the permeated water (ultrapure water) of the ultrafiltration membrane device 40 can be maintained below 5 ng/L, more preferably below 1 ng, by suppressing the increase caused by the ultrafiltration membrane device 40 due to the temperature of the pure water. . In addition, the number of fine particles with a particle diameter of 50 nm or more in the permeated water of the ultrafiltration membrane device 40 is, for example, 200 pcs./L or less, preferably 50 pcs./L or less.

(Second Embodiment) Next, a second embodiment of the present invention will be described. Regarding the ultrafiltration membrane device and the ultrapure water manufacturing method of the second embodiment, basically at the point of using the ultrafiltration membrane module described in the first embodiment, although it has the same structure, it is used as the ultrafiltration membrane device 30 The ultrafiltration module differs only in the point that it consists of two sections connecting two ultrafiltration membrane modules. That is, as shown in Figure 4, can become the structure that connects the 1st ultrafiltration membrane module 30a and the 2nd ultrafiltration membrane module 10, or as shown in Figure 5, as the 1st ultrafiltration membrane module and the 2nd ultrafiltration membrane module Ultrafiltration membrane modules all use the ultrafiltration membrane module 10 of this embodiment, and these can be connected to each other.

The first ultrafiltration membrane module 30a shown in Fig. 4 is not particularly limited to the conventionally known ultrafiltration membrane module, but here, an example of the use of the conventional both ends water collection type ultrafiltration membrane module Case. The ultrafiltration membrane module 30a has nozzles 32a, 32b, and nozzles 36a, 36b, and accommodates hollow fiber membranes made of ultrafiltration membranes inside. From the nozzle 32a connected to the treated water inlet pipe 113 of the treated water supplied to the ultrafiltration membrane device 30, the treated water is introduced into the ultrafiltration membrane module 30a, and the concentrated water that has not passed through the ultrafiltration membrane and the The concentrated water outflow pipe 111 connected to the nozzle 32b flows out. On the other hand, the permeated water passing through the ultrafiltration membrane flows out from the permeated water outflow pipe 114 connected to the nozzles 36b arranged at both ends, and after making it all merge, it is used as the treated water of the second ultrafiltration membrane module 10, It is introduced into the second ultrafiltration membrane module 10 from the nozzle 2a connected to the treated water pipe 103 . The treatment in the second ultrafiltration membrane module is as described in the first embodiment. Still, in this second ultrafiltration membrane module, although the concentrated water can flow out, the valve V1 can also be closed to achieve full filtration.

In addition, FIG. 5 exemplifies the case where two ultrafiltration membrane modules of this embodiment are used. Here, the first ultrafiltration membrane module 10A or the second ultrafiltration membrane module 10B is the ultrafiltration membrane module 10 of the above-mentioned present embodiment, and the flow of the treated water is as described above. The water pipes 103A and 103B introduce the water to be treated, the concentrated water flows out from the concentrated water pipes 101A and 101B, the discharged water flows out from the discharge water pipes 102A and 102B, and the permeated water flows out from the permeated water pipes 104A and 104B. Still, in the present embodiment, the permeated water passing through the ultrafiltration membrane of the first ultrafiltration membrane module 10A flows out from the permeated water pipe 104A connected with the nozzle 6b, directly as the treated water of the second ultrafiltration membrane module 10B, From the nozzle 2a connected to the treated water pipe 103B, it is introduced into the second ultrafiltration membrane module. Moreover, as explained in FIG. 4 above, even with the configuration in FIG. 5 here, although the treatment in the second ultrafiltration membrane module can make the concentrated water flow out, the valve V1 can also be closed to achieve full filtration.

With the configuration shown in Fig. 4 and Fig. 5, since most of the microparticles are removed in the first ultrafiltration membrane module, the load of microparticles in the second ultrafiltration membrane module almost disappears, and the operation can be performed with full filtration. By performing full-volume filtration, the recovery rate can be improved, and furthermore, the breakage of the hollow fiber membrane housed in the ultrafiltration membrane module can be suppressed. Again, in this embodiment, since the ultrafiltration membrane module is defined as 2 sections as mentioned above, and the second ultrafiltration membrane module is the ultrafiltration membrane module described in the above-mentioned first embodiment, it can be obtained Great effect of ultrapure water that significantly reduces ionic components such as chloride ions.

Still, in FIG. 4 and FIG. 5, the ultrafiltration membrane module 10 of this embodiment used as the second ultrafiltration module can also be used with the nozzle 6a side vertically (downward). In this case, the water to be treated is introduced from the introduction pipe below the second outer limit module 10, that is, the nozzle 2a, and the permeated water passing through the hollow fiber membrane is obtained from the nozzle 6b in the vertical direction (upper), and passes through the hollow fiber membrane, so that The discharge water flows out from the nozzle 6a in the vertical direction (downward). The concentrated water that has not passed through the hollow fiber membrane can flow out from the nozzle 2b, but it can also be filtered in full if it does not flow out as described above.

The effect of performing full-volume filtration is the same as above, and although disconnection can be suppressed, the following effects are further exhibited. In the case of the configuration of the vertical second ultrafiltration module 10, if the hollow fiber membrane is disconnected, it is highly likely that the disconnection will occur at the interface Fa of the fixed part on the nozzle 2a side where the water to be treated is introduced. In this case, the disconnection occurs on the lower side, that is, on the outflow side of the drain water. Therefore, the water to be treated that becomes a problem flows out from the nozzle 6a in the vertical direction (below) of the second ultrafiltration membrane module, and there is no influence on the treated water flowing out from the nozzle 6b in the vertical direction (upper), which can be stable ensure the quality of treated water.

[Example] Next, examples will be described. The present invention is not limited to the following examples.

(Manufacture of warm pure water) Using an ultrafiltration membrane module (OLT-6036VA manufactured by Asahi Kasei Co., Ltd.) of the external pressure type water collection at both ends, water treatment was performed as follows. Still, the ultrafiltration membrane module used in this example is the same three-dimensional structure as that of Figure 1, although the water to be treated is introduced from the nozzle 2a, and the concentrated water flows out from the nozzle 2b, but the water is collected from the nozzle 2b. Both sides of 6a and nozzle 6b are designed in the way of collecting and permeating water.

In addition, the specifications of OLT-6036VA manufactured by Asahi Kasei Co., Ltd. are as follows. The inner diameter of the hollow fiber membrane is 0.6mm, the effective membrane area is ^34m2 , the inner diameter of the module (tubular box) is 172mm, the length of the module (tubular box) is 1177mm, the nominal fractional molecular weight of the ultrafiltration membrane is 6000, and the maximum differential pressure inside and outside the membrane is 300kPa 25℃)

An ultrapure water production system having the same secondary pure water production unit 13 as the ultrapure water production system shown in FIG. 3 was used. This secondary pure water production is downstream of the storage tank that stores the primary pure water, and is equipped with a first heat exchanger, an ultraviolet oxidation device (manufactured by Japan Photo Science Co., Ltd., JPW-2), and a palladium (Pd)-carrying resin in sequence. Device (manufactured by LANXESS, Lewatit K7333), degassing membrane device (manufactured by 3M Company, X40 G451H), non-regenerative mixed-bed ion exchange device (manufactured by Nomura Micro Science, filled with 200L N-Lite MBSP), the above-mentioned ultrafiltration Membrane device (manufactured by Asahi Kasei Co., Ltd., OLT-6036VA). Furthermore, a 2nd heat exchanger is provided. In the first heat exchanger, the temperature of the primary pure water is adjusted at 23±3°C, and in the second heat exchanger, the permeated water of the ultrafiltration membrane device is heated to 80°C. Still, in the ultrafiltration membrane module configured in the ultrafiltration membrane device used in the manufacture of warm pure water, water is collected and permeated in the way of collecting water at both ends. The water quality of the obtained warm pure water is that the specific resistivity is above 17MΩ･cm, the TOC concentration is below 5μgC/L, the number of particles above 50μm is about 200pcs./L, and the chloride ion concentration is 25ng/L.

(Embodiment 1) Although the ultrafiltration membrane module of the above-mentioned external pressure type water collection at both ends has basically the same structure, the permeate water flows out from the nozzle 6b, and the discharge water flows out from the nozzle 6a. The ultrafiltration membrane module for water, from the nozzle 2a arranged on the side of the cylindrical box, introduces the above-mentioned warm pure water (pure water heated to 80°C) into the ultrafiltration membrane module, and performs filtration treatment with external pressure . The opening of the valve V1 was set so that the outflow of concentrated water from the nozzle 2b would be 3% of the flow rate (m ³ /h) of the primary pure water supplied from the nozzle 2a. In addition, among the water passing through the ultrafiltration membrane, the flow rate flowing out from the nozzle 6a as discharge water is set to 2% relative to the total flow rate flowing out from the nozzle 6a and the nozzle 6b, so that the amount of permeated water collected from the nozzle 6b becomes 98%. The way to set the opening of the valve V2.

The ultrafiltration membrane module is used upright with the nozzle 6a side facing the vertical direction (downward). The concentration of chloride ions (as Cl) in permeated water was measured with respect to the time from the supply of warm pure water in the ultrafiltration membrane module. The results are shown in Table 1. Here, the chloride ion concentration was measured using ion chromatography (Dionex ICS-5000, manufactured by Thermo Fisher Scientific).

(comparative example) Using the above-mentioned ultrafiltration membrane module of the external pressure type water collection at both ends, the same as in embodiment 1, the above-mentioned warm pure water (pure water heated to 80° C.) is introduced into the ultrafiltration membrane module through the nozzle 2a. However, the concentrated water flows out from the nozzle 2b with the same flow rate as that of Example 1 (relative to the flow rate of the primary pure water supplied, which is 3% of the concentrated water outflow), and is configured from the nozzles 6a and the two ends of the ultrafiltration membrane module. 6b Both sides, catch water and permeate water. In the same manner as in Example 1, the change over time of the concentration of chloride ions (as Cl) in the permeated water was measured with respect to the number of days when the supply of warm pure water from the ultrafiltration membrane module started. The results are shown in Table 1. Moreover, the change with time of the chloride ion concentration of Example 1 and the comparative example is shown in the graph of FIG. 6.

(Example 2) In Example 1, by setting the opening degree of the valve V2, the flow rate that flows out from the nozzle 6a as discharge water is in the range of 0% to 10% as shown in Table 2 with respect to the total flow rate that flows out from the nozzle 6a and the nozzle 6b. In a change, the permeated water is collected from the nozzle 6b. Measure the concentration of chloride ions (as Cl) in the obtained permeated water from the beginning of passing the warm pure water to the ultrafiltration membrane module to 55 days later. The results are shown in Table 2. In addition, the relationship between the ratio of the flow rate of the permeated water and the concentration of chloride ions in the permeated water in Example 2 is shown in the graph of FIG. 7 .

1: Hollow fiber membrane 2: Cylindrical case 2a, 2b: Nozzle 3a, 3b: Fixing part 4: Heat exchanger (HEX) 6a, 6b: Nozzle 60a, 60b: Piping connection cap 61a, 61b: Contact part 101: Concentrated water pipe 102: Discharge water pipe 103: Treated water pipe 104: Permeated water pipe V1, V2: Valve 11: Pretreatment section 12: Primary pure water production section 13: Secondary pure water production section 14: Storage tank 34, 41: Heat exchange Device (HEX) 35: Ultraviolet oxidation device (TOC-UV) 36: Hydrogen peroxide removal device (H ₂ O ₂ removal device) 37: Degassing membrane device 38: Non-regenerative mixed bed ion exchange resin 30, 40: Ultrafiltration membrane device 50, 51: Use point (POU) 100: Ultrapure water manufacturing system P: Pump

[FIG. 1] A cross-sectional view schematically showing an ultrafiltration membrane module according to a first embodiment. [ Fig. 2 ] A block diagram schematically showing the ultrapure water production system according to the first embodiment. [ Fig. 3 ] A block diagram schematically showing a modified example of the ultrapure water production system according to the first embodiment. [ Fig. 4 ] A diagram showing a schematic configuration of an ultrafiltration membrane device in an ultrapure water production system according to a second embodiment. [ Fig. 5 ] A diagram showing a schematic configuration of another ultrafiltration membrane device in the ultrapure water production system according to the second embodiment. [ Fig. 6 ] A graph showing the change with time of the concentration of chloride ions in the permeated water of Example 1 and Comparative Example. [ Fig. 7 ] A graph showing the relationship between the discharge flow ratio of permeated water and the concentration of chloride ions in permeated water in Example 2.

1: Hollow fiber membrane

2: Tubular box

2a, 2b: nozzle

3a, 3b: fixed part

10:Ultrafiltration membrane module

6a, 6b: nozzle

60a, 60b: Piping connection caps

61a, 61b: contact part

101: concentrated water pipe

102: Discharge pipe

103: Treated water pipe

104:Through the water pipe

Fa, Fb: interface

V1, V2: valve

Claims (7)

An ultrafiltration membrane module, which is composed of: a plurality of hollow fiber membranes composed of ultrafiltration membranes, and an ultrafiltration membrane module composed of a cylindrical box for accommodating the plurality of hollow fiber membranes, characterized in that The aforementioned cylindrical box is equipped with a first nozzle and a second nozzle, a third nozzle and a fourth nozzle, and a pair of fixing parts, the first nozzle and the second nozzle are arranged on the outer peripheral surface of the cylindrical box, and The axial direction of each other is arranged at a distance from each other. The third nozzle and the fourth nozzle are arranged at both ends of the aforementioned cylindrical box. The opening ends of the fiber membrane are respectively directed to the two ends of the aforementioned cylindrical box, fixed along the axial direction of the aforementioned cylindrical box, and between the end of one side of the aforementioned cylindrical box and the aforementioned first nozzle and the aforementioned Each position between the end of the other side of the cylindrical box and the aforementioned second nozzle seals the aforementioned cylindrical box. The aforementioned first nozzle is a treated water inlet pipe that introduces the treated water. The concentrated water outflow pipe through which the concentrated water of the hollow fiber membrane flows out, the third nozzle is the permeate water outflow pipe through which the permeate water passing through the hollow fiber membrane flows out, and the fourth nozzle is for the discharge water through the hollow fiber membrane to flow out The value of the ratio of the outflow from the aforementioned permeated water outflow pipe to the outflow from the aforementioned drain water outflow pipe (the outflow from the aforementioned permeated water outflow pipe/the outflow from the aforementioned drain water outflow pipe ) is above 90/10 and below 99/1. The ultrafiltration membrane module according to claim 1, wherein the permeated water outflow pipe is arranged closer to the concentrated water outflow pipe than the treated water inlet pipe. The ultrafiltration membrane module according to claim 1 or 2, wherein the fixing part is made of epoxy resin. A method for producing ultrapure water, characterized in that it is composed of: a plurality of hollow fiber membranes composed of ultrafiltration membranes, and an ultrafiltration membrane module composed of a cylindrical box for accommodating the plurality of hollow fiber membranes, and The aforementioned cylindrical box is provided with a first nozzle and a second nozzle, an ultrafiltration module with a third nozzle and a fourth nozzle, and a pair of fixed parts, the first nozzle and the second nozzle are arranged on the outer peripheral surface of the cylindrical box, The axial direction of the aforementioned cylindrical case is arranged at a distance from each other. The third nozzle and the fourth nozzle are arranged at both ends of the aforementioned cylindrical case. The opening ends of the plurality of hollow fiber membranes are fixed along the axial direction of the cylindrical case in such a way that the opening ends of the plurality of hollow fiber membranes point to the two ends of the aforementioned cylindrical case respectively, and the end of one side of the aforementioned cylindrical case is connected to the first Each position between the nozzles and the other end of the aforementioned cylindrical box and the aforementioned second nozzle is sealed in the ultrafiltration membrane module of the aforementioned cylindrical box, and the water to be treated is introduced into the aforementioned ultrafiltration membrane module from the aforementioned first nozzle. In the filter membrane module, the concentrated water that does not pass through the hollow fiber membrane is flowed from the second nozzle From the third nozzle of the cylindrical box, the permeated water passing through the hollow fiber membrane flows out, and the discharged water passing through the hollow fiber membrane flows out from the fourth nozzle, and by passing the outflow from the third nozzle The ratio of the amount relative to the outflow from the fourth nozzle (the outflow from the third nozzle/the outflow from the fourth nozzle) is set at 90/10 or more and 99/1 or less, so that the above-mentioned permeation Water was used as ultrapure water. The method for producing ultrapure water according to claim 4, wherein the concentration of chloride ions (Cl ^- ) in the water to be treated is 0.01 μg/L to 2 μg/L (as Cl). The method for producing ultrapure water according to Claim 4, wherein the chloride ion (Cl ⁻ ) concentration in the water to be treated is 1 ng/L or less (as Cl). The method for producing ultrapure water according to any one of claims 4 to 6, wherein the chloride ion (Cl ⁻ ) concentration in the permeated water of the ultrafiltration membrane module is 5 ng/L or less (as Cl).

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