WO2019188965A1 - Ultrapure water production system and ultrapure water production method - Google Patents

Ultrapure water production system and ultrapure water production method Download PDF

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Publication number
WO2019188965A1
WO2019188965A1 PCT/JP2019/012462 JP2019012462W WO2019188965A1 WO 2019188965 A1 WO2019188965 A1 WO 2019188965A1 JP 2019012462 W JP2019012462 W JP 2019012462W WO 2019188965 A1 WO2019188965 A1 WO 2019188965A1
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Prior art keywords
membrane device
ultrafiltration membrane
ultrapure water
water
water production
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PCT/JP2019/012462
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French (fr)
Japanese (ja)
Inventor
輝 丹治
しおり 永田
野口　幸男
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野村マイクロ・サイエンス株式会社
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Priority to JP2020510065A priority Critical patent/JPWO2019188965A1/en
Priority to KR1020207024838A priority patent/KR20200138181A/en
Publication of WO2019188965A1 publication Critical patent/WO2019188965A1/en

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
    • B01D61/14—Ultrafiltration; Microfiltration
    • B01D61/145—Ultrafiltration
    • B01D61/146—Ultrafiltration comprising multiple ultrafiltration steps
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
    • B01D61/14—Ultrafiltration; Microfiltration
    • B01D61/18—Apparatus therefor
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
    • B01D61/58—Multistep processes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D69/00—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor
    • B01D69/02—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor characterised by their properties
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D71/00—Semi-permeable membranes for separation processes or apparatus characterised by the material; Manufacturing processes specially adapted therefor
    • B01D71/06—Organic material
    • B01D71/30—Polyalkenyl halides
    • B01D71/32—Polyalkenyl halides containing fluorine atoms
    • B01D71/34—Polyvinylidene fluoride
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D71/00—Semi-permeable membranes for separation processes or apparatus characterised by the material; Manufacturing processes specially adapted therefor
    • B01D71/06—Organic material
    • B01D71/30—Polyalkenyl halides
    • B01D71/32—Polyalkenyl halides containing fluorine atoms
    • B01D71/36—Polytetrafluoroethene
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D71/00—Semi-permeable membranes for separation processes or apparatus characterised by the material; Manufacturing processes specially adapted therefor
    • B01D71/06—Organic material
    • B01D71/66—Polymers having sulfur in the main chain, with or without nitrogen, oxygen or carbon only
    • B01D71/68—Polysulfones; Polyethersulfones
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/30—Treatment of water, waste water, or sewage by irradiation
    • C02F1/32—Treatment of water, waste water, or sewage by irradiation with ultraviolet light
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/42—Treatment of water, waste water, or sewage by ion-exchange
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/44—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/44—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis
    • C02F1/444—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis by ultrafiltration or microfiltration
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/58—Treatment of water, waste water, or sewage by removing specified dissolved compounds
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/70—Treatment of water, waste water, or sewage by reduction
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2317/00—Membrane module arrangements within a plant or an apparatus
    • B01D2317/02—Elements in series
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2325/00—Details relating to properties of membranes
    • B01D2325/02—Details relating to pores or porosity of the membranes
    • B01D2325/0283—Pore size
    • B01D2325/02832—1-10 nm
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2325/00—Details relating to properties of membranes
    • B01D2325/02—Details relating to pores or porosity of the membranes
    • B01D2325/0283—Pore size
    • B01D2325/02833—Pore size more than 10 and up to 100 nm
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2103/00—Nature of the water, waste water, sewage or sludge to be treated
    • C02F2103/02—Non-contaminated water, e.g. for industrial water supply
    • C02F2103/04—Non-contaminated water, e.g. for industrial water supply for obtaining ultra-pure water

Definitions

  • the present invention relates to an ultrapure water production system and an ultrapure water production method.
  • ultrapure water used in a semiconductor manufacturing process is manufactured using an ultrapure water manufacturing system.
  • the ultrapure water production system includes, for example, a pretreatment unit that removes suspended substances in raw water to obtain pretreatment water, total organic carbon (TOC) components and ion components in pretreatment water, reverse osmosis membrane devices and ions It consists of a primary pure water production section that produces primary pure water by removing using an exchange device, and a secondary pure water production section that produces ultrapure water by removing trace amounts of impurities in the primary pure water. .
  • TOC total organic carbon
  • secondary pure water production section that produces ultrapure water by removing trace amounts of impurities in the primary pure water.
  • primary pure water is highly processed by an ultraviolet oxidation device, an ion exchange pure water device, an ultrafiltration membrane (UF) device, or the like to generate ultrapure water.
  • the ultrafiltration membrane device is disposed in the vicinity of the last stage of the secondary pure water production unit, and removes fine particles generated from an ion exchange resin or the like.
  • JP 2016-64342 A International Publication No. 2015/050125 JP-A-10-99855
  • the ultrafiltration membranes conventionally used for removing fine particles are not sufficiently resistant to oxidants, so that they gradually deteriorate due to hydrogen peroxide in water, and the ultrafiltration membrane itself may generate dust. I understood. Therefore, there is a problem that it is difficult to obtain ultrapure water with reduced fine 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 capable of obtaining ultrapure water with reduced fine particles for a long period of time.
  • the ultrapure water production system of the present invention has an ultrafiltration membrane device and a filtration membrane device connected in series to the ultrafiltration membrane, and the ultrafiltration membrane device and the filtration membrane device are treated water.
  • the ultrafiltration membrane device has a removal rate of fine particles having a particle diameter of 20 nm or more of 99.8% or more, and the filtration membrane device Is resistant to oxidation and is characterized by comprising a filtration membrane having a pore size of 2 to 40 nm.
  • the ultrafiltration membrane device preferably has an ultrafiltration membrane with a molecular weight cut-off of 3000 to 10,000.
  • the ultrafiltration membrane device preferably has an ultrafiltration membrane made of polysulfone, polyvinylidene fluoride or polytetrafluoroethylene.
  • the filtration membrane device has a filtration membrane made of polyvinylidene fluoride or polytetrafluoroethylene.
  • the ultrapure water production system of the present invention further comprises a hydrogen peroxide removing device upstream of the ultrafiltration membrane device, and the ultrafiltration membrane is treated water of the hydrogen peroxide removing device as the treated water. It is preferable to be able to process in order with an apparatus and the said filtration membrane apparatus.
  • the ultrapure water production system of the present invention comprises, in this order, an ultraviolet oxidation device, a hydrogen peroxide removal device, a degassing membrane device, and a non-regenerative mixed bed ion exchange resin device upstream of the ultrafiltration membrane device, It is preferable that the treated water of the non-regenerative mixed bed ion exchange resin apparatus can be treated with the ultrafiltration membrane apparatus and the filtration membrane apparatus as treated water.
  • water to be treated is passed through an ultrafiltration membrane device, and fine particles having a particle diameter of 20 nm or more are treated with a removal rate of 99.8% or more.
  • the treated water is treated by passing water through a filtration membrane device having a filtration membrane having an oxidation resistance and a pore size of 2 to 40 nm.
  • the water to be treated of the ultrafiltration membrane device contains 0.1 to 3 ⁇ g / L of hydrogen peroxide.
  • ultrapure water with reduced fine particles can be obtained for a long period of time.
  • Ultrafiltration membranes are generally relatively resistant to oxidizing agents such as hydrogen peroxide. Therefore, even when hydrogen peroxide concentration is contained in the water supplied to the ultrafiltration membrane, it is understood that membrane deterioration due to hydrogen peroxide does not occur if the concentration is, for example, about 0.1 to 3 ⁇ g / L. It was. However, when ultrafiltration membranes are passed for a long period of time, depending on the material of the ultrafiltration membrane, there will be a difference in treated water quality after long-term passage, especially the concentration of fine particles in water. It has been found that even such a low concentration of hydrogen peroxide has some influence on the film. And when water was passed for a long time using an ultrafiltration membrane having stronger oxidation resistance, the deterioration of water quality was found to be relatively gradual, and the present invention was completed.
  • oxidizing agents such as hydrogen peroxide
  • the ultrapure water production system 1 includes a pretreatment unit 10, a primary pure water production unit 11, a tank 12, and a secondary pure water production unit 13.
  • An ultrafiltration membrane device 2 and a filtration membrane device 3 for removing fine particles in the water are provided in order in the water production unit 13. Both the pretreatment unit 10 and the primary pure water production unit 11 are provided as necessary.
  • an ultrafiltration membrane device having a high removal rate of fine particles having a particle diameter of less than 50 nm or about 20 nm is used as the ultrafiltration membrane device 2 and the filtration membrane device 3 is used.
  • a filter device having an oxidation resistant ultrafiltration membrane is used.
  • the ultrafiltration membrane device 2 highly removes the fine particles as described above, and the filtration membrane device 3 captures the dust generated when the fine particles have deteriorated. Can be obtained.
  • the ultrafiltration membrane device 2 the filtration membrane device 3, and other devices that the ultrapure water production system 1 have in the ultrapure water production system 1 according to the present embodiment will be described.
  • the pretreatment unit 10 removes suspended substances in the raw water to generate pretreatment water, and supplies the pretreatment water to the primary pure water production unit 11.
  • the pretreatment unit 10 is configured by appropriately selecting, for example, a sand filtration device, a microfiltration device or the like for removing suspended substances in the raw water, and further heat exchange for adjusting the temperature of the treated water as necessary. It is configured with a container.
  • the pretreatment unit 10 may be omitted depending on the quality of the raw water.
  • Raw water is, for example, city water, well water, ground water, industrial water, water used in semiconductor manufacturing factories, etc., collected and processed (recovered water).
  • the primary pure water production unit 11 includes a reverse osmosis membrane device, a degassing device (decarbonation tower, vacuum degassing device, degassing membrane device, etc.), ion exchange device (cation exchange device, anion exchange device, mixed bed type). An ion exchange device or the like) and an ultraviolet oxidation device are appropriately combined.
  • the primary pure water production unit 11 produces primary pure water by removing ionic and nonionic components and dissolved gas in the pretreatment water, and supplies this primary pure water to the tank 12.
  • the primary pure water has, for example, a total organic carbon (TOC) concentration of 5 ⁇ g C / L or less, a resistivity of 17 M ⁇ ⁇ cm or more, and a fine particle number of 20 nm or more of 100,000 psc. / L or less.
  • TOC total organic carbon
  • the tank 12 stores primary pure water and supplies the required amount to the secondary pure water production unit 13.
  • the secondary pure water production unit 13 removes trace impurities in the primary pure water to produce ultrapure water.
  • the secondary pure water production unit 13 includes, for example, a heat exchanger (HEX) 4, an ultraviolet oxidizer (TOC-UV) 5, hydrogen peroxide on the upstream side of the ultrafiltration membrane device 2. It comprises a removal device (H 2 O 2 removal device) 6, a degassing membrane device (MDG) 7, and a non-regenerative mixed bed ion exchange resin device (Polisher) 8.
  • the secondary pure water manufacturing part 13 does not necessarily need to be equipped with the said apparatus, What is necessary is just to employ
  • the heat exchanger (HEX) 4 adjusts the temperature of the primary pure water supplied from the tank 12 as necessary.
  • the temperature of the primary pure water whose temperature is adjusted by the heat exchanger 4 is preferably 25 ⁇ 3 ° C.
  • the ultraviolet oxidizer (TOC-UV) 5 irradiates the primary pure water whose temperature is adjusted by the heat exchanger 4 with ultraviolet rays to decompose and remove trace organic substances in the water.
  • the ultraviolet oxidation device 5 includes, for example, an ultraviolet lamp and generates ultraviolet rays having a wavelength of about 185 nm.
  • the ultraviolet oxidation device 5 may further generate ultraviolet rays having a wavelength of about 254 nm.
  • the ultraviolet irradiation amount in the ultraviolet oxidizer 5 is 0. It is preferably 0.05 to 0.2 kWh / m 3 .
  • the hydrogen peroxide removing device (H 2 O 2 removing device) 6 is a device that decomposes and removes hydrogen peroxide in water.
  • a palladium-carrying resin device that decomposes and removes hydrogen peroxide with a palladium (Pd) -carrying resin
  • examples thereof include a reducing resin device having a surface filled with a reducing resin having a sulfite group and / or a hydrogen sulfite group. Since the hydrogen peroxide concentration in the water can be reduced by providing the hydrogen peroxide removing device 6, deterioration of the ultrafiltration membrane of the ultrafiltration membrane device 2 can be suppressed.
  • the degassing membrane device (MDG) 7 is a device that depressurizes the secondary side of the gas-permeable membrane and allows only the dissolved gas in water flowing through the primary side to permeate to the secondary side and remove it.
  • MDG degassing membrane device
  • commercially available products such as X-50 and X40 manufactured by 3M, and Separel manufactured by DIC can be used as the deaeration membrane device 7.
  • the degassing membrane device 7 removes dissolved oxygen in the treated water obtained from the hydrogen peroxide removing device 6 to generate treated water having a dissolved oxygen concentration (DO) of 1 ⁇ g / L or less, for example.
  • DO dissolved oxygen concentration
  • the non-regenerative type mixed bed type ion exchange resin apparatus (Polisher) 8 has a mixed bed type ion exchange resin in which a cation exchange resin and an anion exchange resin are mixed. Adsorption and removal of cation and anion components.
  • the non-regenerative mixed bed type ion exchange resin device 8 is a device that mixes and accommodates a cation exchange resin and an anion exchange resin therein.
  • the cation exchange resin used here include strong acid cation exchange resins and weak acid cation exchange resins. Strong acid cation exchange resins are preferred, and anion exchange resins are strongly basic anion exchange resins. Examples thereof include resins and weakly basic anion exchange resins, and strong basic anion exchange resins are preferred.
  • As the mixed bed type ion exchange resin it is preferable to use a mixture of a strongly acidic cation exchange resin and a strongly basic anion exchange resin, and as a commercially available product, for example, N-Lite MBSP manufactured by Nomura Micro Science Co., Ltd. MBGP or the like can be used.
  • the ultrafiltration membrane device 2 processes the treated water of the non-regenerative mixed bed ion exchange resin device 8 to generate permeated water and concentrated water.
  • the removal rate of fine particles having a particle diameter of 20 nm or more is 99.8% or more, preferably 99.95% or more, and more preferably 99.99% or more.
  • the ultrafiltration membrane device 2 removes most of the fine particles that cause deterioration of the water quality of ultrapure water. / L or less, or even 50 pcs. / L or less permeated water can be obtained.
  • the ultrafiltration membrane device 2 can remove fine particles having a particle diameter of 10 nm or more with the above-described removal rate, thereby further improving the quality of ultrapure water so that the number of fine particles having a particle diameter of 10 nm or more is 200 pcs. / L or less, or even 50 pcs. / L or less permeated water can be obtained.
  • the permeated water generated in the ultrafiltration membrane device 2 is supplied to the subsequent filtration membrane device 3.
  • the concentrated water is discharged out of the system, or is circulated and reprocessed before the ultrapure water production system.
  • the ultrafiltration membrane device 2 treats the treated water of the non-regenerative mixed bed ion exchange resin device 8 in FIG. 2 above, but is not limited thereto, and water from which coarse particles have been removed.
  • it may be treated water after being treated in the pretreatment unit, and pretreated water, primary treated water, secondary treated water (including circulating water) and the like are treated water. And can.
  • the ultrafiltration membrane device 2 has such a particulate removal rate as described above for such water to be treated.
  • As the water to be treated it is more preferable to use the treated water of the suspended substance removing device provided to the pretreatment unit 10 or the treated water of the reverse osmosis membrane device provided to the primary pure water production unit 11.
  • the ultrafiltration membrane device 2 is preferably provided in the secondary pure water production unit 13.
  • the fine particle removal rate is, for example, the number of fine particles having a predetermined particle diameter or more in the permeated water when fine particle-containing water pressurized to 0.1 MPa is passed through the film to be measured at a water recovery rate of 95% or more. And the number of fine particles having a predetermined particle diameter in the feed water, and ⁇ 1- (number of fine particles having a predetermined particle diameter in permeated water / number of fine particles having a predetermined particle diameter in supply water) ⁇ ⁇ 100 (%) Can be calculated.
  • the removal rate can be confirmed by mixing polystyrene latex (manufactured by Thermo Fisher, model number 3020A, nominal diameter 20 nm) with ultrapure water and charging 500,000 / ml to the water supplied to the membrane device to be measured.
  • Such an ultrafiltration membrane device 2 is preferably a device having an ultrafiltration membrane having a fractional molecular weight of preferably 3000 to 10000, more preferably 4000 to 8000, because a high particulate removal rate can be easily obtained.
  • the fractional molecular weight of the ultrafiltration membrane can be measured, for example, as follows. Sample water containing a plurality of different types of marker molecules with known molecular weights is passed through the ultrafiltration membrane to be measured, and the removal rate of the marker molecules is measured. The measurement result of the removal rate obtained is plotted against the molecular weight to create a fraction curve. The molecular weight with a removal rate of 90%, for example, is determined from the fraction curve as the fraction molecular weight of the membrane.
  • the marker molecule dextran, polyethylene glycol (PEG), protein or the like is used.
  • the ultrafiltration membrane of the ultrafiltration membrane device 2 is, for example, an asymmetric membrane or a composite membrane, such as polysulfone, polyolefin, polyester, polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), polyethersulfone, or polyamide. Is preferably used as a material.
  • the membrane shape is a sheet flat membrane, a spiral membrane, a tubular membrane, a hollow fiber membrane or the like, but is not limited thereto. Since a high fine particle removal rate can be obtained, those made of polysulfone are more preferable.
  • the ultrafiltration membrane which the ultrafiltration membrane apparatus 2 has does not need to have oxidation resistance like the ultrafiltration membrane which the filtration membrane apparatus 3 mentioned later has.
  • Effective membrane area of the ultrafiltration membrane device 2 is preferably 5m 2 ⁇ 60m 2, 10m 2 ⁇ 50m 2 is more preferable. 15 m 2 to 40 m 2 is more preferable, and when the effective film area is in the above range, deterioration of the film is easily suppressed.
  • the water recovery rate in the ultrafiltration membrane device 2 is preferably 95% or more, and more preferably 99% or more. Thereby, the production efficiency of ultrapure water can be improved while obtaining ultrapure water from which fine particles are highly removed.
  • the hydrogen peroxide concentration in the treated water is 0. 1 to 3 ⁇ g / L is preferable, and 0.2 to 1 ⁇ g / L is more preferable.
  • the hydrogen peroxide concentration in the water to be treated of the ultrafiltration membrane device 2 is in the above-described range, it is easy to suppress the deterioration of the ultrafiltration membrane and obtain ultrapure water from which fine particles are highly removed over a longer period of time. Can do.
  • the filtration membrane device 3 processes the permeated water of the ultrafiltration membrane device 2 to generate permeated water and concentrated water.
  • the filtration membrane device 3 has an oxidation resistance and a filtration membrane having a pore diameter of 2 to 40 nm.
  • Examples of such a filtration membrane include an ultrafiltration membrane (UF) and a microfiltration membrane (MF) composed of PVDF or PTFE as a material.
  • Examples of the membrane shape include, but are not limited to, a sheet flat membrane, a spiral membrane, a tubular membrane, and a hollow fiber membrane.
  • the oxidation resistance of the filtration membrane is, for example, the one whose decrease in permeate amount is less than 5% before the test after being immersed in 5% by mass of hydrogen peroxide solution for 10 days, or its tensile strength. It can be judged that the amount of change is less than 5% with respect to the strength before the test as having oxidation resistance.
  • the film is not limited to a film that is determined to have oxidation resistance by the above method, and a film that is nominally considered to have hydrogen peroxide resistance or oxidation resistance may be used.
  • the filtration membrane device 3 since most of the fine particles in water are removed by the ultrafiltration membrane device 2, the filtration membrane device 3 does not have to realize the high particulate removal rate as that of the ultrafiltration membrane device 2. Therefore, the removal rate of fine particles having a particle diameter of 20 nm or more in the filtration membrane device 3 is preferably 40 to 95%, more preferably 60 to 90%.
  • the ultrafiltration membrane of the ultrafiltration membrane device 2 deteriorates due to, for example, hydrogen peroxide flowing out from the ultraviolet oxidizer 5, and dust is generated. There is. This dust generation is, for example, about 20 to 100 nm. Therefore, the pore size of the filtration membrane in the filtration membrane device 3 is preferably 5 to 40 nm, and more preferably 10 to 30 nm. The pore size of the filtration membrane can be determined by the nominal pore size. Alternatively, it can be measured using a substance having a known particle diameter by the same method as that for the ultrafiltration membrane.
  • the ultrafiltration membrane in the filtration membrane device 3 preferably has a pore size of 5 to 40 nm, 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. Thereby, the production efficiency of ultrapure water can be improved while obtaining ultrapure water from which fine particles are highly removed.
  • the number of fine particles having a particle diameter of 20 nm or more is preferably 500 pcs. / L or less, more preferably 200 pcs. / P or less ultrapure water can be obtained. More preferably, the number of fine particles having a particle diameter of 20 nm or more is preferably 50 pcs.
  • High purity ultrapure water of / L or less can be obtained.
  • the quality of ultrapure water is, for example, a total organic carbon (TOC) concentration of 1 ⁇ g C / L or less and a resistivity of 18 M ⁇ ⁇ cm or more.
  • the ultrapure water generated by the filtration membrane device 3 is supplied to a place (POU) where ultrapure water is used.
  • the ultrapure water production system 1 of the present embodiment when the ultrafiltration membrane of the ultrafiltration membrane device 2 does not have oxidation resistance, hydrogen peroxide flowing out from the ultraviolet oxidation device 5 The ultrafiltration membrane may gradually deteriorate and generate dust. However, dust generated from the ultrafiltration membrane is removed by the subsequent filtration membrane device 3. Therefore, according to the ultrapure water production system 1 of the present embodiment, ultrapure water from which fine particles are highly removed can be obtained even if the ultrafiltration membrane in the previous stage is deteriorated.
  • ultrapure water from which fine particles are highly removed can be obtained over a long period of time.
  • Example 2 An ultrapure water production system having a secondary pure water production unit similar to that shown in FIG. 2 was used.
  • This secondary pure water production department is equipped with a heat exchanger, an ultraviolet oxidation device (JPW-2, manufactured by Nippon Photo Science Co., Ltd.), a Pd-supporting resin device (LANXESS, Lewatit K7333) downstream of the tank for storing the primary pure water.
  • JPW-2 ultraviolet oxidation device
  • LANXESS Lewatit K7333
  • Degassing membrane device (3M, X40 G451H), non-regenerative mixed bed type ion exchanger (Nomura Micro Science N-Lite MBSP 200L filling), ultrafiltration membrane device (Asahi Kasei, OAT- 6036HA (fractionated molecular weight (nominal): 4000, effective membrane area: 34 m 2 ) and a filtration membrane device (manufactured by Nihon Entegris, Trinzik nominal pore size 15 nm) are provided in this order.
  • Table 1 shows changes over time in the number of fine particles having a particle diameter of 0.4 ⁇ m or more in the permeated water of the filtration membrane device when primary pure water is supplied to the secondary pure water production department and ultrapure water is produced for 8 years. Show. A direct microscopic method was used to measure the number of fine particles. A Hitachi electron microscope was used for the measurement.
  • the number of fine particles is 1000 pcs. / L.
  • the number of fine particles having a particle size of 0.4 ⁇ m or more was 0 even after 8 years. .5 pcs. Since the number of fine particles of 20 nm or more by UltraDI-20 was also the same as the initial value, the ultrafine particles were reduced over a long period of time compared to the configuration of the comparative example in which no filtration membrane device was provided. It can be seen that pure water was obtained.
  • SYMBOLS 1 Ultrapure water production system, 2 ... Ultrafiltration membrane apparatus, 3 ... Filtration membrane apparatus, 4 ... Heat exchanger (HEX), 5 ... Ultraviolet oxidation apparatus (TOC-UV), 6 ... Hydrogen peroxide removal apparatus, DESCRIPTION OF SYMBOLS 7 ... Degassing membrane apparatus (MDG), 8 ... Non-regenerative mixed bed type ion exchange resin apparatus (Polisher), 10 ... Pretreatment part, 11 ... Primary pure water production part, 12 ... Tank, 13 ... Secondary pure water Production department.
  • HEX Heat exchanger
  • TOC-UV Ultraviolet oxidation apparatus
  • MDG Degassing membrane apparatus
  • Polyisher Non-regenerative mixed bed type ion exchange resin apparatus

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

超純水製造システム及び超純水製造方法Ultrapure water production system and ultrapure water production method
　本発明は、超純水製造システム及び超純水製造方法に関する。 The present invention relates to an ultrapure water production system and an ultrapure water production method.
　従来、半導体製造工程で使用する超純水は、超純水製造システムを用いて製造されている。超純水製造システムは、例えば、原水中の懸濁物質を除去して前処理水を得る前処理部、前処理水中の全有機炭素（ＴＯＣ）成分やイオン成分を、逆浸透膜装置やイオン交換装置を用いて除去して一次純水を製造する一次純水製造部及び一次純水中の極微量の不純物を除去して超純水を製造する二次純水製造部で構成されている。原水としては、市水、井水、地下水、工業用水等が用いられる他、超純水の使用場所（ユースポイント：ＰＯＵ）で回収された使用済みの超純水（以下、「回収水」と称する。）が用いられる。 Conventionally, ultrapure water used in a semiconductor manufacturing process is manufactured using an ultrapure water manufacturing system. The ultrapure water production system includes, for example, a pretreatment unit that removes suspended substances in raw water to obtain pretreatment water, total organic carbon (TOC) components and ion components in pretreatment water, reverse osmosis membrane devices and ions It consists of a primary pure water production section that produces primary pure water by removing using an exchange device, and a secondary pure water production section that produces ultrapure water by removing trace amounts of impurities in the primary pure water. . As raw water, city water, well water, groundwater, industrial water, etc. are used, and used ultrapure water (hereinafter referred to as “recovered water”) collected at the place of use of ultrapure water (use point: POU). Is used).
　二次純水製造部では、紫外線酸化装置、イオン交換純水装置及び限外ろ過膜（ＵＦ）装置等により一次純水が高度に処理されて超純水が生成する。限外ろ過膜装置は、この二次純水製造部の最後段付近に配置され、イオン交換樹脂などから生じる微粒子を除去する。 In the secondary pure water production department, primary pure water is highly processed by an ultraviolet oxidation device, an ion exchange pure water device, an ultrafiltration membrane (UF) device, or the like to generate ultrapure water. The ultrafiltration membrane device is disposed in the vicinity of the last stage of the secondary pure water production unit, and removes fine particles generated from an ion exchange resin or the like.
　ところで、超純水については、高純度化に対する要求が年々高まってきており、例えば微粒子濃度は、粒子径が５０ｎｍ以上の微粒子数で、１０００ｐｃｓ．／Ｌ以下が求められている。さらに、要求水質はより厳しくなる傾向にあり、粒子径が５０ｎｍ未満、例えば１０ｎｍ程度の微粒子の低減も求められてきている。そのため、より粒子径の小さな微粒子を高度に除去する方法が提案されている（例えば、特許文献１、２参照。）。 By the way, with respect to ultrapure water, the demand for high purity is increasing year by year. For example, the fine particle concentration is 1000 pcs. / L or less is required. Furthermore, the required water quality tends to be severer, and the reduction of fine particles having a particle diameter of less than 50 nm, for example, about 10 nm has been demanded. Therefore, a method for highly removing fine particles having a smaller particle diameter has been proposed (see, for example, Patent Documents 1 and 2).
　また、超純水水質の向上を目的として、超純水プラントの上流で生じたコンタミネーション分や粒状形成分を最末端に配置した限外ろ過膜装置で除去する方法も提案されている（例えば、特許文献３参照。） In addition, for the purpose of improving the quality of ultrapure water, a method has been proposed in which contaminants and particulates formed upstream of the ultrapure water plant are removed with an ultrafiltration membrane device arranged at the end (for example, , See Patent Document 3.)
特開２０１６－６４３４２号公報JP 2016-64342 A 国際公開２０１５／０５０１２５号International Publication No. 2015/050125 特開平１０－９９８５５号公報JP-A-10-99855
　ところで、従来微細微粒子の除去に用いられる限外ろ過膜は、酸化剤への耐性が十分でないために水中の過酸化水素によって徐々に劣化して、限外ろ過膜自体が発塵を生じることも分かった。そのため、微粒子が低減された超純水を長期間得難いという課題があった。 By the way, the ultrafiltration membranes conventionally used for removing fine particles are not sufficiently resistant to oxidants, so that they gradually deteriorate due to hydrogen peroxide in water, and the ultrafiltration membrane itself may generate dust. I understood. Therefore, there is a problem that it is difficult to obtain ultrapure water with reduced fine particles for a long period of time.
　本発明は、微粒子が低減された超純水を長期間得ることのできる超純水製造システム及び超純水製造方法を提供することを目的とする。 An object of the present invention is to provide an ultrapure water production system and an ultrapure water production method capable of obtaining ultrapure water with reduced fine particles for a long period of time.
　本発明の超純水製造システムは、限外ろ過膜装置と該限外ろ過膜に直列に接続されたろ過膜装置とを有し、被処理水を前記限外ろ過膜装置と前記ろ過膜装置で順に処理して超純水を製造する超純水製造システムであって、前記限外ろ過膜装置は、粒子径２０ｎｍ以上の微粒子の除去率が９９．８％以上であり、前記ろ過膜装置は、耐酸化剤性であり、孔径が２～４０ｎｍのろ過膜を具備することを特徴とする。 The ultrapure water production system of the present invention has an ultrafiltration membrane device and a filtration membrane device connected in series to the ultrafiltration membrane, and the ultrafiltration membrane device and the filtration membrane device are treated water. In the ultrapure water production system for producing ultrapure water in order, the ultrafiltration membrane device has a removal rate of fine particles having a particle diameter of 20 nm or more of 99.8% or more, and the filtration membrane device Is resistant to oxidation and is characterized by comprising a filtration membrane having a pore size of 2 to 40 nm.
　本発明の超純水製造システムにおいて、前記限外ろ過膜装置は、分画分子量が３０００～１００００の限外ろ過膜を有することが好ましい。また、前記限外ろ過膜装置はポリスルホン、ポリフッ化ビニリデン又はポリテトラフルオロエチレンを材料とする限外ろ過膜を有することが好ましい。 In the ultrapure water production system of the present invention, the ultrafiltration membrane device preferably has an ultrafiltration membrane with a molecular weight cut-off of 3000 to 10,000. The ultrafiltration membrane device preferably has an ultrafiltration membrane made of polysulfone, polyvinylidene fluoride or polytetrafluoroethylene.
　本発明の超純水製造システムにおいて、前記ろ過膜装置は、ポリフッ化ビニリデン又はポリテトラフルオロエチレンを材料とするろ過膜を有することが好ましい。 In the ultrapure water production system of the present invention, it is preferable that the filtration membrane device has a filtration membrane made of polyvinylidene fluoride or polytetrafluoroethylene.
　本発明の超純水製造システムは、前記限外ろ過膜装置の上流に、さらに過酸化水素除去装置を有し、前記過酸化水素除去装置の処理水を前記被処理水として前記限外ろ過膜装置と前記ろ過膜装置とで順に処理可能とすることが好ましい。 The ultrapure water production system of the present invention further comprises a hydrogen peroxide removing device upstream of the ultrafiltration membrane device, and the ultrafiltration membrane is treated water of the hydrogen peroxide removing device as the treated water. It is preferable to be able to process in order with an apparatus and the said filtration membrane apparatus.
　本発明の超純水製造システムは、前記限外ろ過膜装置の上流に、紫外線酸化装置、過酸化水素除去装置、脱気膜装置及び非再生型混床式イオン交換樹脂装置をこの順に備え、前記非再生型混床式イオン交換樹脂装置の処理水を被処理水として前記限外ろ過膜装置及びろ過膜装置で処理可能とすることが好ましい。 The ultrapure water production system of the present invention comprises, in this order, an ultraviolet oxidation device, a hydrogen peroxide removal device, a degassing membrane device, and a non-regenerative mixed bed ion exchange resin device upstream of the ultrafiltration membrane device, It is preferable that the treated water of the non-regenerative mixed bed ion exchange resin apparatus can be treated with the ultrafiltration membrane apparatus and the filtration membrane apparatus as treated water.
　本発明の超純水製造方法は、被処理水を限外ろ過膜装置に通水して、粒子径２０ｎｍ以上の微粒子を９９．８％以上の除去率で処理し、前記限外ろ過膜装置の処理水を、耐酸化剤性であり、孔径が２～４０ｎｍのろ過膜を具備するろ過膜装置に通水して処理する、ことを特徴とする。 In the ultrapure water production method of the present invention, water to be treated is passed through an ultrafiltration membrane device, and fine particles having a particle diameter of 20 nm or more are treated with a removal rate of 99.8% or more. The treated water is treated by passing water through a filtration membrane device having a filtration membrane having an oxidation resistance and a pore size of 2 to 40 nm.
　本発明の超純水製造方法において、前記限外ろ過膜装置の被処理水は過酸化水素を０．１～３μｇ／Ｌ含むことが好ましい。 In the ultrapure water production method of the present invention, it is preferable that the water to be treated of the ultrafiltration membrane device contains 0.1 to 3 μg / L of hydrogen peroxide.
　本発明の超純水製造システム及び超純水製造方法によれば、微粒子が低減された超純水を長期間得ることができる。 According to the ultrapure water production system and the ultrapure water production method of the present invention, ultrapure water with reduced fine particles can be obtained for a long period of time.
実施形態に係る超純水製造システムを表すブロック図である。It is a block diagram showing the ultrapure water manufacturing system which concerns on embodiment. 実施形態に係る二次純水製造部を表すブロック図である。It is a block diagram showing the secondary pure water manufacturing part which concerns on embodiment.
　限外ろ過膜は、一般的に過酸化水素等の酸化剤に対して比較的耐性がある。したがって、限外ろ過膜への供給水に過酸化水素濃度が含有される場合でも、例えば、０．１～３μｇ／Ｌ程度の濃度であれば、過酸化水素による膜劣化は起きないと理解されていた。ところが、限外ろ過膜を長期通水した場合、限外ろ過膜の素材によって、長期通水後の処理水水質、特に水中の微粒子濃度に違いが生じること、つまり、長期通水すると、上記のような低濃度の過酸化水素であっても、膜に対して何らかの影響があることが分かってきた。そして、より耐酸化剤性の強い限外ろ過膜を用いて長期通水をした場合、水質の悪化が比較的緩やかであることを見出して、本発明の完成に至った。 Ultrafiltration membranes are generally relatively resistant to oxidizing agents such as hydrogen peroxide. Therefore, even when hydrogen peroxide concentration is contained in the water supplied to the ultrafiltration membrane, it is understood that membrane deterioration due to hydrogen peroxide does not occur if the concentration is, for example, about 0.1 to 3 μg / L. It was. However, when ultrafiltration membranes are passed for a long period of time, depending on the material of the ultrafiltration membrane, there will be a difference in treated water quality after long-term passage, especially the concentration of fine particles in water. It has been found that even such a low concentration of hydrogen peroxide has some influence on the film. And when water was passed for a long time using an ultrafiltration membrane having stronger oxidation resistance, the deterioration of water quality was found to be relatively gradual, and the present invention was completed.
　以下、図面を参照して、本発明の一実施形態を詳細に説明する。図１に示すように、本実施形態に係る超純水製造システム１は、前処理部１０、一次純水製造部１１、タンク１２及び二次純水製造部１３を備えており、二次純水製造部１３内に水中の微粒子を除去する限外ろ過膜装置２とろ過膜装置３を順に備えている。前処理部１０及び一次純水製造部１１はいずれも、必要に応じて備えられる。 Hereinafter, an 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 according to the present embodiment includes a pretreatment unit 10, a primary pure water production unit 11, a tank 12, and a secondary pure water production unit 13. An ultrafiltration membrane device 2 and a filtration membrane device 3 for removing fine particles in the water are provided in order in the water production unit 13. Both the pretreatment unit 10 and the primary pure water production unit 11 are provided as necessary.
　本実施形態の超純水製造システム１では、限外ろ過膜装置２として粒子径が５０ｎｍ未満やさらに２０ｎｍ程度の微細微粒子の除去率の高い限外ろ過膜装置を用いるとともに、ろ過膜装置３として耐酸化剤性の限外ろ過膜を有するフィルター装置を用いる。これにより、限外ろ過膜装置２によって、上記のような微細微粒子を高度に除去するとともに、これが劣化してきた際の発塵をろ過膜装置３で捕捉することで、長期にわたって微粒子が高度に除去された超純水を得ることができる。 In the ultrapure water production system 1 of the present embodiment, an ultrafiltration membrane device having a high removal rate of fine particles having a particle diameter of less than 50 nm or about 20 nm is used as the ultrafiltration membrane device 2 and the filtration membrane device 3 is used. A filter device having an oxidation resistant ultrafiltration membrane is used. As a result, the ultrafiltration membrane device 2 highly removes the fine particles as described above, and the filtration membrane device 3 captures the dust generated when the fine particles have deteriorated. Can be obtained.
　以下、本実施形態に係る超純水製造システム１が有する限外ろ過膜装置２、ろ過膜装置３及び超純水製造システム１が必要に応じて有するその他の装置について説明する。 Hereinafter, the ultrafiltration membrane device 2, the filtration membrane device 3, and other devices that the ultrapure water production system 1 have in the ultrapure water production system 1 according to the present embodiment will be described.
　前処理部１０は、原水中の懸濁物質を除去して、前処理水を生成し、この前処理水を一次純水製造部１１に供給する。前処理部１０は、例えば、原水中の懸濁物質を除去するための砂ろ過装置、精密ろ過装置等を適宜選択して構成され、さらに必要に応じて被処理水の温度調節を行う熱交換器等を備えて構成される。なお、原水の水質によっては、前処理部１０は省略してもよい。 The pretreatment unit 10 removes suspended substances in the raw water to generate pretreatment water, and supplies the pretreatment water to the primary pure water production unit 11. The pretreatment unit 10 is configured by appropriately selecting, for example, a sand filtration device, a microfiltration device or the like for removing suspended substances in the raw water, and further heat exchange for adjusting the temperature of the treated water as necessary. It is configured with a container. The pretreatment unit 10 may be omitted depending on the quality of the raw water.
　原水は、例えば、市水、井水、地下水、工業用水、半導体製造工場などで使用され、回収されて処理された水（回収水）である。 Raw water is, for example, city water, well water, ground water, industrial water, water used in semiconductor manufacturing factories, etc., collected and processed (recovered water).
　一次純水製造部１１は、逆浸透膜装置、脱気装置（脱炭酸塔、真空脱気装置、脱気膜装置等）、イオン交換装置（陽イオン交換装置、陰イオン交換装置、混床式イオン交換装置等）、紫外線酸化装置のうち１つ以上を適宜組み合わせて構成される。一次純水製造部１１は、前処理水中のイオン成分及び非イオン成分、溶存ガスを除去して一次純水を製造し、この一次純水をタンク１２に供給する。一次純水は、例えば、全有機炭素（ＴＯＣ）濃度が５μｇＣ／Ｌ以下、抵抗率が１７ＭΩ・ｃｍ以上、粒子径２０ｎｍ以上の微粒子数が１０００００ｐｓｃ．／Ｌ以下である。 The primary pure water production unit 11 includes a reverse osmosis membrane device, a degassing device (decarbonation tower, vacuum degassing device, degassing membrane device, etc.), ion exchange device (cation exchange device, anion exchange device, mixed bed type). An ion exchange device or the like) and an ultraviolet oxidation device are appropriately combined. The primary pure water production unit 11 produces primary pure water by removing ionic and nonionic components and dissolved gas in the pretreatment water, and supplies this primary pure water to the tank 12. The primary pure water 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 fine particle number of 20 nm or more of 100,000 psc. / L or less.
　タンク１２は、一次純水を貯留して、その必要量を二次純水製造部１３に供給する。 The tank 12 stores primary pure water and supplies the required amount to the secondary pure water production unit 13.
　二次純水製造部１３は、一次純水中の微量不純物を除去して超純水を製造する。図２に示すように、二次純水製造部１３は、例えば、限外ろ過膜装置２の上流側に、熱交換器（ＨＥＸ）４、紫外線酸化装置（ＴＯＣ－ＵＶ）５、過酸化水素除去装置（Ｈ２Ｏ２除去装置）６、脱気膜装置（ＭＤＧ）７及び非再生型混床式イオン交換樹脂装置（Ｐｏｌｉｓｈｅｒ）８を備えて構成される。なお、二次純水製造部１３は、上記装置を必ずしも備える必要はなく、上記装置を必要に応じて組み合わせて採用すればよい。 The secondary pure water production unit 13 removes trace impurities in the primary pure water to produce ultrapure water. As shown in FIG. 2, the secondary pure water production unit 13 includes, for example, a heat exchanger (HEX) 4, an ultraviolet oxidizer (TOC-UV) 5, hydrogen peroxide on the upstream side of the ultrafiltration membrane device 2. It comprises a removal device (H 2 O 2 removal device) 6, a degassing membrane device (MDG) 7, and a non-regenerative mixed bed ion exchange resin device (Polisher) 8. In addition, the secondary pure water manufacturing part 13 does not necessarily need to be equipped with the said apparatus, What is necessary is just to employ | adopt combining the said apparatus as needed.
　熱交換器（ＨＥＸ）４は、必要に応じてタンク１２から供給された一次純水の温度調節を行う。熱交換器４で温度調節された一次純水の温度は好ましくは２５±３℃である。 The heat exchanger (HEX) 4 adjusts the temperature of the primary pure water supplied from the tank 12 as necessary. The temperature of the primary pure water whose temperature is adjusted by the heat exchanger 4 is preferably 25 ± 3 ° C.
　紫外線酸化装置（ＴＯＣ－ＵＶ）５は、上記熱交換器４で温度調節された一次純水に紫外線を照射して、水中の微量有機物を分解除去する。紫外線酸化装置５は、例えば、紫外線ランプを有し、波長１８５ｎｍ付近の紫外線を発生する。紫外線酸化装置５は、さらに波長２５４ｎｍ付近の紫外線を発生してもよい。紫外線酸化装置５内で水に紫外線を照射すると紫外線が水を分解してＯＨラジカルを生成し、このＯＨラジカルが、水中の有機物を酸化分解する。紫外線酸化装置において過剰の紫外線照射が行われた場合、有機物の酸化分解に寄与しないＯＨラジカル同士が反応して過酸化水素が発生する。この発生した過酸化水素は、下流の限外ろ過膜装置２の有する限外ろ過膜を劣化させることがある。 The ultraviolet oxidizer (TOC-UV) 5 irradiates the primary pure water whose temperature is adjusted by the heat exchanger 4 with ultraviolet rays to decompose and remove trace organic substances in the water. The ultraviolet oxidation device 5 includes, for example, an ultraviolet lamp and generates ultraviolet rays having a wavelength of about 185 nm. The ultraviolet oxidation device 5 may further generate ultraviolet rays having a wavelength of about 254 nm. When water is irradiated with ultraviolet rays in the ultraviolet oxidizer 5, the ultraviolet rays decompose water to generate OH radicals, and the OH radicals oxidize and decompose organic substances in water. When excessive ultraviolet irradiation is performed in the ultraviolet oxidation apparatus, OH radicals that do not contribute to oxidative decomposition of organic matter react with each other to generate hydrogen peroxide. The generated hydrogen peroxide may deteriorate the ultrafiltration membrane of the downstream ultrafiltration membrane device 2.
　そのため、紫外線酸化装置５から流出する過酸化水素を低減して、下流の限外ろ過膜装置２の有する限外ろ過膜の劣化を抑制するために、紫外線酸化装置５における紫外線照射量は、０．０５～０．２ｋＷｈ／ｍ３であることが好ましい。 Therefore, in order to reduce the hydrogen peroxide flowing out from the ultraviolet oxidizer 5 and suppress the deterioration of the ultrafiltration membrane of the downstream ultrafiltration membrane device 2, the ultraviolet irradiation amount in the ultraviolet oxidizer 5 is 0. It is preferably 0.05 to 0.2 kWh / m 3 .
　過酸化水素除去装置（Ｈ２Ｏ２除去装置）６は、水中の過酸化水素を分解除去する装置であり、例えば、パラジウム（Ｐｄ）担持樹脂によって過酸化水素を分解除去するパラジウム担持樹脂装置や表面に亜硫酸基及び／又は亜硫酸水素基を有する還元性樹脂を充填した還元性樹脂装置等が挙げられる。過酸化水素除去装置６を設けることで、水中の過酸化水素濃度を低減することができるので、限外ろ過膜装置２の有する限外ろ過膜の劣化を抑制することができる。 The hydrogen peroxide removing device (H 2 O 2 removing device) 6 is a device that decomposes and removes hydrogen peroxide in water. For example, a palladium-carrying resin device that decomposes and removes hydrogen peroxide with a palladium (Pd) -carrying resin, Examples thereof include a reducing resin device having a surface filled with a reducing resin having a sulfite group and / or a hydrogen sulfite group. Since the hydrogen peroxide concentration in the water can be reduced by providing the hydrogen peroxide removing device 6, deterioration of the ultrafiltration membrane of the ultrafiltration membrane device 2 can be suppressed.
　脱気膜装置（ＭＤＧ）７は、気体透過性の膜の二次側を減圧して、一次側を通流する水中の溶存ガスのみを二次側に透過させて除去する装置である。脱気膜装置７として具体的には、３Ｍ社製のＸ－５０、Ｘ４０、ＤＩＣ社製のＳｅｐａｒｅｌなどの市販品を用いることができる。脱気膜装置７は、過酸化水素除去装置６から得られる処理水中の溶存酸素を除去して、例えば、溶存酸素濃度（ＤＯ）が１μｇ／Ｌ以下の処理水を生成する。 The degassing membrane device (MDG) 7 is a device that depressurizes the secondary side of the gas-permeable membrane and allows only the dissolved gas in water flowing through the primary side to permeate to the secondary side and remove it. Specifically, commercially available products such as X-50 and X40 manufactured by 3M, and Separel manufactured by DIC can be used as the deaeration membrane device 7. The degassing membrane device 7 removes dissolved oxygen in the treated water obtained from the hydrogen peroxide removing device 6 to generate treated water having a dissolved oxygen concentration (DO) of 1 μg / L or less, for example.
　非再生型混床式イオン交換樹脂装置（Ｐｏｌｉｓｈｅｒ）８は、陽イオン交換樹脂と陰イオン交換樹脂が混合された混床式イオン交換樹脂を有し、脱気膜装置７の処理水中の微量の陽イオン成分及び陰イオン成分を吸着除去する。 The non-regenerative type mixed bed type ion exchange resin apparatus (Polisher) 8 has a mixed bed type ion exchange resin in which a cation exchange resin and an anion exchange resin are mixed. Adsorption and removal of cation and anion components.
　非再生型混床式イオン交換樹脂装置８は、その内部に陽イオン交換樹脂と陰イオン交換樹脂とを混合して収容する装置である。ここで用いられる陽イオン交換樹脂としては、強酸性陽イオン交換樹脂や弱酸性陽イオン交換樹脂が挙げられ、強酸性陽イオン交換樹脂が好ましく、陰イオン交換樹脂としては、強塩基性陰イオン交換樹脂や弱塩基性陰イオン交換樹脂が挙げられ、強塩基性陰イオン交換樹脂が好ましい。混床式イオン交換樹脂としては、強酸性陽イオン交換樹脂と強塩基性陰イオン交換樹脂を混合したものを用いることが好ましく、その市販品としては、例えば、野村マイクロ・サイエンス製 Ｎ－Ｌｉｔｅ　ＭＢＳＰ、ＭＢＧＰなどを用いることができる。 The non-regenerative mixed bed type ion exchange resin device 8 is a device that mixes and accommodates a cation exchange resin and an anion exchange resin therein. Examples of the cation exchange resin used here include strong acid cation exchange resins and weak acid cation exchange resins. Strong acid cation exchange resins are preferred, and anion exchange resins are strongly basic anion exchange resins. Examples thereof include resins and weakly basic anion exchange resins, and strong basic anion exchange resins are preferred. As the mixed bed type ion exchange resin, it is preferable to use a mixture of a strongly acidic cation exchange resin and a strongly basic anion exchange resin, and as a commercially available product, for example, N-Lite MBSP manufactured by Nomura Micro Science Co., Ltd. MBGP or the like can be used.
　限外ろ過膜装置２は、非再生型混床式イオン交換樹脂装置８の処理水を処理して、透過水と濃縮水を生成する。限外ろ過膜装置２は、粒子径２０ｎｍ以上の微粒子の除去率が９９.８％以上であり、９９．９５％以上であることが好ましく、９９．９９％以上であることがさらに好ましい。これにより限外ろ過膜装置２によって、超純水の水質悪化の原因となる微粒子のほとんどが除去され、例えば、粒子径２０ｎｍ以上の微粒子数が２００ｐｃｓ．／Ｌ以下、さらには５０ｐｃｓ．／Ｌ以下の透過水を得ることができる。限外ろ過膜装置２は、粒子径１０ｎｍ以上の微粒子を上記の除去率で除去できることがさらに好ましく、これにより、超純水の水質をより向上させて、粒子径１０ｎｍ以上の微粒子数が２００ｐｃｓ．／Ｌ以下、さらには５０ｐｃｓ．／Ｌ以下の透過水を得ることができる。限外ろ過膜装置２において生成した透過水は後段のろ過膜装置３に供給される。濃縮水は系外に排出されるか、超純水製造システムの前段に循環されて再処理される。 The ultrafiltration membrane device 2 processes the treated water of the non-regenerative mixed bed ion exchange resin device 8 to generate permeated water and concentrated water. In the ultrafiltration membrane device 2, the removal rate of fine particles having a particle diameter of 20 nm or more is 99.8% or more, preferably 99.95% or more, and more preferably 99.99% or more. As a result, the ultrafiltration membrane device 2 removes most of the fine particles that cause deterioration of the water quality of ultrapure water. / L or less, or even 50 pcs. / L or less permeated water can be obtained. It is further preferable that the ultrafiltration membrane device 2 can remove fine particles having a particle diameter of 10 nm or more with the above-described removal rate, thereby further improving the quality of ultrapure water so that the number of fine particles having a particle diameter of 10 nm or more is 200 pcs. / L or less, or even 50 pcs. / L or less permeated water can be obtained. The permeated water generated in the ultrafiltration membrane device 2 is supplied to the subsequent filtration membrane device 3. The concentrated water is discharged out of the system, or is circulated and reprocessed before the ultrapure water production system.
　なお、限外ろ過膜装置２は、上記では図２の非再生型混床式イオン交換樹脂装置８の処理水を処理することとしているが、これに限られず、粗大な粒子が除去された水、例えば、超純水製造装置における、前処理部で処理された以降の処理水であればよく、前処理水、一次処理水、二次処理水（循環させる場合も含む）等を被処理水とできる。限外ろ過膜装置２は、このような被処理水に対して、上記のような微粒子の除去率を有するものである。この被処理水としては、前処理部１０に供えられた懸濁物質除去装置の処理水や、１次純水製造部１１に供えられた逆浸透膜装置の処理水を用いることがより好ましい。また、限外ろ過膜装置２は二次純水製造部１３内に供えられることが好ましい。 The ultrafiltration membrane device 2 treats the treated water of the non-regenerative mixed bed ion exchange resin device 8 in FIG. 2 above, but is not limited thereto, and water from which coarse particles have been removed. For example, in the ultrapure water production apparatus, it may be treated water after being treated in the pretreatment unit, and pretreated water, primary treated water, secondary treated water (including circulating water) and the like are treated water. And can. The ultrafiltration membrane device 2 has such a particulate removal rate as described above for such water to be treated. As the water to be treated, it is more preferable to use the treated water of the suspended substance removing device provided to the pretreatment unit 10 or the treated water of the reverse osmosis membrane device provided to the primary pure water production unit 11. The ultrafiltration membrane device 2 is preferably provided in the secondary pure water production unit 13.
　なお、微粒子除去率は、例えば、測定対象の膜に、０．１ＭＰａに加圧した微粒子含有水を水回収率９５％以上で通水した際の、透過水中の所定の粒子径以上の微粒子数と供給水中の所定の粒子径の微粒子数とを測定し、｛１－（透過水中の所定の粒子径の微粒子数／供給水中の所定の粒子径以上の微粒子数）｝×１００（％）で算出することができる。除去率は、ポリスチレンラテックス（Ｔｈｅｒｍｏ　Ｆｉｓｈｅｒ製、型番　３０２０Ａ　呼径２０ｎｍ）を超純水に混合し、測定対象の膜装置の供給水に５０００００個／ｍｌをチャージして確かめられる。 The fine particle removal rate is, for example, the number of fine particles having a predetermined particle diameter or more in the permeated water when fine particle-containing water pressurized to 0.1 MPa is passed through the film to be measured at a water recovery rate of 95% or more. And the number of fine particles having a predetermined particle diameter in the feed water, and {1- (number of fine particles having a predetermined particle diameter in permeated water / number of fine particles having a predetermined particle diameter in supply water)} × 100 (%) Can be calculated. The removal rate can be confirmed by mixing polystyrene latex (manufactured by Thermo Fisher, model number 3020A, nominal diameter 20 nm) with ultrapure water and charging 500,000 / ml to the water supplied to the membrane device to be measured.
　このような限外ろ過膜装置２としては、高い微粒子除去率が得やすいため、分画分子量が好ましくは３０００～１００００、より好ましくは４０００～８０００の限外ろ過膜を有する装置が好適である。なお、限外ろ過膜の分画分子量は、例えば、次のようにして測定することができる。分子量が既知でかつ異なる複数種のマーカー分子を含有する試料水を測定対象の限外ろ過膜に通水して当該マーカー分子の除去率を測定する。得られた除去率の測定結果を分子量に対してプロットして分画曲線を作成する。この分画曲線から除去率が例えば９０％の分子量をその膜の分画分子量とする。マーカー分子としては、デキストラン、ポリエチレングリコール（ＰＥＧ）、タンパク質等が用いられる。 Such an ultrafiltration membrane device 2 is preferably a device having an ultrafiltration membrane having a fractional molecular weight of preferably 3000 to 10000, more preferably 4000 to 8000, because a high particulate removal rate can be easily obtained. The fractional molecular weight of the ultrafiltration membrane can be measured, for example, as follows. Sample water containing a plurality of different types of marker molecules with known molecular weights is passed through the ultrafiltration membrane to be measured, and the removal rate of the marker molecules is measured. The measurement result of the removal rate obtained is plotted against the molecular weight to create a fraction curve. The molecular weight with a removal rate of 90%, for example, is determined from the fraction curve as the fraction molecular weight of the membrane. As the marker molecule, dextran, polyethylene glycol (PEG), protein or the like is used.
　限外ろ過膜装置２が有する限外ろ過膜は、例えば、非対称膜や複合膜であり、ポリスルホン、ポリオレフィン、ポリエステル、ポリテトラフルオロエチレン（ＰＴＦＥ）、ポリフッ化ビニリデン（ＰＶＤＦ）、ポリエーテルスルホン又はポリアミドを材料として構成されることが好ましい。膜形状は、シート平膜、スパイラル膜、管状膜、中空糸膜等であるが、これらに限定されない。高い微粒子除去率が得られるためポリスルホン製のものがより好ましい。なお、限外ろ過膜装置２の有する限外ろ過膜は後述するろ過膜装置３の有する限外ろ過膜のような耐酸化剤性を有しなくても構わない。 The ultrafiltration membrane of the ultrafiltration membrane device 2 is, for example, an asymmetric membrane or a composite membrane, such as polysulfone, polyolefin, polyester, polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), polyethersulfone, or polyamide. Is preferably used as a material. The membrane shape is a sheet flat membrane, a spiral membrane, a tubular membrane, a hollow fiber membrane or the like, but is not limited thereto. Since a high fine particle removal rate can be obtained, those made of polysulfone are more preferable. In addition, the ultrafiltration membrane which the ultrafiltration membrane apparatus 2 has does not need to have oxidation resistance like the ultrafiltration membrane which the filtration membrane apparatus 3 mentioned later has.
　限外ろ過膜装置２における有効膜面積は、５ｍ２～６０ｍ２が好ましく、１０ｍ２～５０ｍ２がより好ましい。１５ｍ２～４０ｍ２がさらに好ましく、有効膜面積が上記した範囲であると、膜の劣化を抑制し易い。 Effective membrane area of the ultrafiltration membrane device 2 is preferably 5m 2 ~ 60m 2, 10m 2 ~ 50m 2 is more preferable. 15 m 2 to 40 m 2 is more preferable, and when the effective film area is in the above range, deterioration of the film is easily suppressed.
　限外ろ過膜装置２における水回収率は９５％以上が好ましく、９９％以上がより好ましい。これにより、微粒子が高度に除去された超純水を得ながら、超純水の製造効率を向上させることができる。 The water recovery rate in the ultrafiltration membrane device 2 is preferably 95% or more, and more preferably 99% or more. Thereby, the production efficiency of ultrapure water can be improved while obtaining ultrapure water from which fine particles are highly removed.
　限外ろ過膜装置２の被処理水、すなわち非再生型混床式イオン交換樹脂装置８の処理水が上記したように過酸化水素を含む場合、被処理水中の過酸化水素濃度は、０．１～３μｇ／Ｌが好ましく、０．２～１μｇ／Ｌがより好ましい。限外ろ過膜装置２の被処理水中の過酸化水素濃度が上記した範囲であると、限外ろ過膜の劣化を抑制し易く、より長期にわたって微粒子が高度に除去された超純水を得ることができる。 When the treated water of the ultrafiltration membrane device 2, that is, the treated water of the non-regenerative mixed bed ion exchange resin device 8, contains hydrogen peroxide as described above, the hydrogen peroxide concentration in the treated water is 0. 1 to 3 μg / L is preferable, and 0.2 to 1 μg / L is more preferable. When the hydrogen peroxide concentration in the water to be treated of the ultrafiltration membrane device 2 is in the above-described range, it is easy to suppress the deterioration of the ultrafiltration membrane and obtain ultrapure water from which fine particles are highly removed over a longer period of time. Can do.
　ろ過膜装置３は、限外ろ過膜装置２の透過水を処理して透過水と濃縮水を生成する。ろ過膜装置３は耐酸化剤性を有し、孔径が２～４０ｎｍのろ過膜を具備する。このようなろ過膜としては、例えば、ＰＶＤＦ又はＰＴＦＥ等を材料として構成される限外ろ過膜（ＵＦ）や精密ろ過膜（ＭＦ）が挙げられる。膜形状としては、シート平膜、スパイラル膜、管状膜、中空糸膜等が挙げられるが、これらに限定されない。なお、ろ過膜の耐酸化剤性は、例えば、５質量％の過酸化水素水に１０日間浸漬した後、その透過水量の減少が、試験前の５％未満であるもの、又はその引っ張り強度の変化量が、試験前の強度に対して５％未満であるもの、を耐酸化剤性有りと判断することができる。また、上記の方法で耐酸化剤性を有すると判断される膜に限らず、耐過酸化水素性、あるいは耐酸化性を有すると公称される膜を用いてもよい。 The filtration membrane device 3 processes the permeated water of the ultrafiltration membrane device 2 to generate permeated water and concentrated water. The filtration membrane device 3 has an oxidation resistance and a filtration membrane having a pore diameter of 2 to 40 nm. Examples of such a filtration membrane include an ultrafiltration membrane (UF) and a microfiltration membrane (MF) composed of PVDF or PTFE as a material. Examples of the membrane shape include, but are not limited to, a sheet flat membrane, a spiral membrane, a tubular membrane, and a hollow fiber membrane. In addition, the oxidation resistance of the filtration membrane is, for example, the one whose decrease in permeate amount is less than 5% before the test after being immersed in 5% by mass of hydrogen peroxide solution for 10 days, or its tensile strength. It can be judged that the amount of change is less than 5% with respect to the strength before the test as having oxidation resistance. Further, the film is not limited to a film that is determined to have oxidation resistance by the above method, and a film that is nominally considered to have hydrogen peroxide resistance or oxidation resistance may be used.
　上述したように水中の微粒子のほとんどは、限外ろ過膜装置２で除去されるので、ろ過膜装置３は、限外ろ過膜装置２ほどの高い微粒子除去率を実現しなくても構わない。そのためろ過膜装置３における粒子径２０ｎｍ以上の微粒子の除去率は好ましくは４０～９５％、より好ましくは６０～９０％であればよい。 As described above, since most of the fine particles in water are removed by the ultrafiltration membrane device 2, the filtration membrane device 3 does not have to realize the high particulate removal rate as that of the ultrafiltration membrane device 2. Therefore, the removal rate of fine particles having a particle diameter of 20 nm or more in the filtration membrane device 3 is preferably 40 to 95%, more preferably 60 to 90%.
　また、超純水製造システム１による超純水の長期製造時には、例えば紫外線酸化装置５から流出する過酸化水素によって限外ろ過膜装置２の有する限外ろ過膜が劣化して発塵を生じることがある。この発塵は、例えば、２０～１００ｎｍ程度である。そのため、ろ過膜装置３におけるろ過膜の孔径は５～４０ｎｍであることが好ましく、１０～３０ｎｍであることがより好ましい。このろ過膜の孔径は、公称孔径で判断することができる。または上記限外ろ過膜と同様の方法で、粒子径が既知の物質を用いて測定することができる。 Further, during the long-term production of ultrapure water by the ultrapure water production system 1, the ultrafiltration membrane of the ultrafiltration membrane device 2 deteriorates due to, for example, hydrogen peroxide flowing out from the ultraviolet oxidizer 5, and dust is generated. There is. This dust generation is, for example, about 20 to 100 nm. Therefore, the pore size of the filtration membrane in the filtration membrane device 3 is preferably 5 to 40 nm, and more preferably 10 to 30 nm. The pore size of the filtration membrane can be determined by the nominal pore size. Alternatively, it can be measured using a substance having a known particle diameter by the same method as that for the ultrafiltration membrane.
　上記微粒子除去率が得やすいため、ろ過膜装置３における限外ろ過膜としては、孔径が好ましくは５～４０ｎｍ、より好ましくは１０～３０ｎｍであるのが好適である。 Since it is easy to obtain the fine particle removal rate, the ultrafiltration membrane in the filtration membrane device 3 preferably has a pore size of 5 to 40 nm, more preferably 10 to 30 nm.
　ろ過膜装置３における水回収率は８０％以上が好ましく、９９％以上がより好ましい。これにより、微粒子が高度に除去された超純水を得ながら、超純水の製造効率を向上させることができる。 The water recovery rate in the filtration membrane device 3 is preferably 80% or more, and more preferably 99% or more. Thereby, the production efficiency of ultrapure water can be improved while obtaining ultrapure water from which fine particles are highly removed.
　ろ過膜装置３の透過水として、粒子径２０ｎｍ以上の微粒子数が好ましくは５００ｐｃｓ．／Ｌ以下であり、より好ましくは２００ｐｃｓ．／Ｌ以下の超純水を得ることができる。さらに好ましくは、ろ過膜装置３の透過水として、粒子径２０ｎｍ以上の微粒子数が好ましくは５０ｐｃｓ．／Ｌ以下のさらに高純度の超純水を得ることができる。また、超純水の水質は、例えば、全有機炭素（ＴＯＣ）濃度が１μｇＣ／Ｌ以下、抵抗率が１８ＭΩ・ｃｍ以上である。ろ過膜装置３で生成した超純水は超純水の使用場所（ＰＯＵ）へ供給される。 As the permeated water of the filtration membrane device 3, the number of fine particles having a particle diameter of 20 nm or more is preferably 500 pcs. / L or less, more preferably 200 pcs. / P or less ultrapure water can be obtained. More preferably, the number of fine particles having a particle diameter of 20 nm or more is preferably 50 pcs. High purity ultrapure water of / L or less can be obtained. The quality of ultrapure water is, for example, a total organic carbon (TOC) concentration of 1 μg C / L or less and a resistivity of 18 MΩ · cm or more. The ultrapure water generated by the filtration membrane device 3 is supplied to a place (POU) where ultrapure water is used.
　本実施形態の超純水製造システム１では、限外ろ過膜装置２の限外ろ過膜が耐酸化剤性を有していない場合には、上記紫外線酸化装置５から流出した過酸化水素によって、当該限外ろ過膜が徐々に劣化して発塵が生じてくることもある。しかしながら、この限外ろ過膜からの発塵は、後段のろ過膜装置３で除去される。そのため、本実施形態の超純水製造システム１によれば、前段の限外ろ過膜が劣化しても微粒子が高度に除去された超純水を得ることができる。 In the ultrapure water production system 1 of the present embodiment, when the ultrafiltration membrane of the ultrafiltration membrane device 2 does not have oxidation resistance, hydrogen peroxide flowing out from the ultraviolet oxidation device 5 The ultrafiltration membrane may gradually deteriorate and generate dust. However, dust generated from the ultrafiltration membrane is removed by the subsequent filtration membrane device 3. Therefore, according to the ultrapure water production system 1 of the present embodiment, ultrapure water from which fine particles are highly removed can be obtained even if the ultrafiltration membrane in the previous stage is deteriorated.
　以上で説明した実施形態の超純水製造システム及び超純水製造方法によれば、微粒子が高度に除去された超純水を長期にわたって得ることができる。 According to the ultrapure water production system and the ultrapure water production method of the embodiment described above, ultrapure water from which fine particles are highly removed can be obtained over a long period of time.
　以下、実施例を用いて本発明を詳細に説明する。本発明は以下の実施例に限定されない。
（実施例）
　図２に示すのと同様の二次純水製造部を有する超純水製造システムを使用した。この二次純水製造部は一次純水を貯留するタンクの下流に、熱交換器、紫外線酸化装置（日本フォトサイエンス社製、ＪＰＷ－２）、Ｐｄ担持樹脂装置（ＬＡＮＸＥＳＳ社製、Ｌｅｗａｔｉｔ　Ｋ７３３３）、脱気膜装置（３Ｍ社製、Ｘ４０　Ｇ４５１Ｈ）、非再生型混床式イオン交換装置（野村マイクロ・サイエンス製　Ｎ－Ｌｉｔｅ　ＭＢＳＰを２００Ｌ充填）、限外ろ過膜装置（旭化成社製、ＯＡＴ－６０３６ＨＡ（分画分子量（公称）：４０００、有効膜面積：３４ｍ２）及びろ過膜装置（日本インテグリス社製、Ｔｒｉｎｚｉｋ　公称孔径１５ｎｍ）を順に備えている。 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 unit similar to that shown in FIG. 2 was used. This secondary pure water production department is equipped with a heat exchanger, an ultraviolet oxidation device (JPW-2, manufactured by Nippon Photo Science Co., Ltd.), a Pd-supporting resin device (LANXESS, Lewatit K7333) downstream of the tank for storing the primary pure water. Degassing membrane device (3M, X40 G451H), non-regenerative mixed bed type ion exchanger (Nomura Micro Science N-Lite MBSP 200L filling), ultrafiltration membrane device (Asahi Kasei, OAT- 6036HA (fractionated molecular weight (nominal): 4000, effective membrane area: 34 m 2 ) and a filtration membrane device (manufactured by Nihon Entegris, Trinzik nominal pore size 15 nm) are provided in this order.
　上記の二次純水製造部に一次純水を供給して超純水を８年間製造した際の、ろ過膜装置の透過水中の粒子径０．４μｍ以上の微粒子数の経時変化を表１に示す。微粒子数の測定には、直接検鏡法を用いた。計測には日立製電子顕微鏡を用いた。 Table 1 shows changes over time in the number of fine particles having a particle diameter of 0.4 μm or more in the permeated water of the filtration membrane device when primary pure water is supplied to the secondary pure water production department and ultrapure water is produced for 8 years. Show. A direct microscopic method was used to measure the number of fine particles. A Hitachi electron microscope was used for the measurement.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
　また、通水年数８年の時に、Ｐａｒｔｉｃｌｅ　Ｍｅａｓｕｒｉｎｇ　Ｓｙｓｔｅｍｓ社製の微粒子計ＵｌｔｒａＤＩ－２０にて、２０ｎｍ以上の微粒子を測定したところ、微粒子数は５００ｐｃｓ．／Ｌ以下であった。また、実施例１を再試験し、通水年数１年の微粒子数をＵＤＩ－２０で測定したところ、微粒子数は５００ｐｃｓ．／Ｌ以下であった。 In addition, when the water flow was 8 years, when measuring fine particles of 20 nm or more with a particle measuring device UltraDI-20 manufactured by Particle Measuring Systems, the number of fine particles was 500 pcs. / L or less. In addition, when Example 1 was retested and the number of fine particles in a water passage year was measured with UDI-20, the number of fine particles was 500 pcs. / L or less.
（比較例）
　実施例で使用した超純水製造システムにおいて、限外ろ過膜装置の後段のろ過膜装置を有しない点のみが異なるシステムに、実施例と同様に一次純水を供給して超純水を８年間製造した際の、限外ろ過膜装置の透過水中の粒子径０．４μｍ以上の微粒子数の経時変化を測定した。結果を表２に示す。 (Comparative example)
In the ultrapure water production system used in the example, primary pure water is supplied to the system which is different only in that it does not have a filtration membrane device subsequent to the ultrafiltration membrane device, and ultrapure water is supplied in the same manner as in the example. The change over time in the number of fine particles having a particle diameter of 0.4 μm or more in the permeated water of the ultrafiltration membrane device was measured over the course of the year. The results are shown in Table 2.
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
　また、通水年数８年の時に、Ｐａｒｔｉｃｌｅ　Ｍｅａｓｕｒｉｎｇ　Ｓｙｓｔｅｍｓ社製の微粒子計ＵｌｔｒａＤＩ－２０にて、２０ｎｍ以上の微粒子を測定したところ、微粒子数は１０００ｐｃｓ．／Ｌであった。 In addition, when the water flow is 8 years, when measuring fine particles of 20 nm or more with a particle measuring device UltraDI-20 manufactured by Particle Measuring Systems, the number of fine particles is 1000 pcs. / L.
　表１、２に示されるように、限外ろ過膜装置の後段にろ過膜装置を設けた実施例の超純水製造システムでは、８年経過後も粒子径０．４μｍ以上の微粒子数が０．５ｐｃｓ．／Ｌ以下であり、また、ＵｌｔｒａＤＩ－２０による２０ｎｍ以上の微粒子数も、初期と同様であったことから、ろ過膜装置を設けない比較例の構成に比べて、長期にわたって微粒子が低減された超純水が得られたことが分かる。 As shown in Tables 1 and 2, in the ultrapure water production system of the example in which the filtration membrane device was provided at the subsequent stage of the ultrafiltration membrane device, the number of fine particles having a particle size of 0.4 μm or more was 0 even after 8 years. .5 pcs. Since the number of fine particles of 20 nm or more by UltraDI-20 was also the same as the initial value, the ultrafine particles were reduced over a long period of time compared to the configuration of the comparative example in which no filtration membrane device was provided. It can be seen that pure water was obtained.
　１…超純水製造システム、２…限外ろ過膜装置、３…ろ過膜装置、４…熱交換器（ＨＥＸ）、５…紫外線酸化装置（ＴＯＣ－ＵＶ）、６…過酸化水素除去装置、７…脱気膜装置（ＭＤＧ）、８…非再生型混床式イオン交換樹脂装置（Ｐｏｌｉｓｈｅｒ）、１０…前処理部、１１…一次純水製造部、１２…タンク、１３…二次純水製造部。 DESCRIPTION OF SYMBOLS 1 ... Ultrapure water production system, 2 ... Ultrafiltration membrane apparatus, 3 ... Filtration membrane apparatus, 4 ... Heat exchanger (HEX), 5 ... Ultraviolet oxidation apparatus (TOC-UV), 6 ... Hydrogen peroxide removal apparatus, DESCRIPTION OF SYMBOLS 7 ... Degassing membrane apparatus (MDG), 8 ... Non-regenerative mixed bed type ion exchange resin apparatus (Polisher), 10 ... Pretreatment part, 11 ... Primary pure water production part, 12 ... Tank, 13 ... Secondary pure water Production department.

Claims (8)

  1. 　限外ろ過膜装置と該限外ろ過膜に直列に接続されたろ過膜装置とを有し、被処理水を前記限外ろ過膜装置と前記ろ過膜装置で順に処理して超純水を製造する超純水製造システムであって、
    　前記限外ろ過膜装置は、粒子径２０ｎｍ以上の微粒子の除去率が９９．８％以上であり、
    　前記ろ過膜装置は、耐酸化剤性であり、孔径が２～４０ｎｍのろ過膜を具備することを特徴とする超純水製造システム。     It has an ultrafiltration membrane device and a filtration membrane device connected in series to the ultrafiltration membrane, and produces ultrapure water by treating the water to be treated in order with the ultrafiltration membrane device and the filtration membrane device. An ultrapure water production system,
    The ultrafiltration membrane device has a removal rate of fine particles having a particle diameter of 20 nm or more of 99.8% or more,
    The ultrapure water production system, wherein the filtration membrane device is provided with a filtration membrane having an oxidation resistance and a pore diameter of 2 to 40 nm.
  2. 　前記限外ろ過膜装置は、分画分子量が３０００～１００００の限外ろ過膜を有することを特徴とする請求項１に記載の超純水製造システム。 2. The ultrapure water production system according to claim 1, wherein the ultrafiltration membrane device has an ultrafiltration membrane having a molecular weight cut-off of 3000 to 10,000.
  3. 　前記限外ろ過膜装置は、ポリスルホン、ポリフッ化ビニリデン又はポリテトラフルオロエチレンを材料とする限外ろ過膜を有することを特徴とする請求項１又は２に記載の超純水製造システム。 3. The ultrapure water production system according to claim 1 or 2, wherein the ultrafiltration membrane device has an ultrafiltration membrane made of polysulfone, polyvinylidene fluoride or polytetrafluoroethylene.
  4. 　前記ろ過膜装置は、ポリフッ化ビニリデン又はポリテトラフルオロエチレンを材料とするろ過膜を有することを特徴とする請求項１乃至３のいずれか１項に記載の超純水製造システム。 The ultrapure water production system according to any one of claims 1 to 3, wherein the filtration membrane device has a filtration membrane made of polyvinylidene fluoride or polytetrafluoroethylene.
  5. 　前記限外ろ過膜装置の上流に、さらに過酸化水素除去装置を有し、前記過酸化水素除去装置の処理水を前記被処理水として前記限外ろ過膜装置と前記ろ過膜装置とで順に処理可能とすることを特徴とする請求項１乃至４のいずれか１項に記載の超純水製造システム。 A hydrogen peroxide removal device is further provided upstream of the ultrafiltration membrane device, and the treated water of the hydrogen peroxide removal device is treated as the water to be treated in the order of the ultrafiltration membrane device and the filtration membrane device. The ultrapure water production system according to any one of claims 1 to 4, wherein the system is possible.
  6. 　前記限外ろ過膜装置の上流に、紫外線酸化装置、過酸化水素除去装置、脱気膜装置及び非再生型混床式イオン交換樹脂装置をこの順に備え、
    　前記非再生型混床式イオン交換樹脂装置の処理水を被処理水として前記限外ろ過膜装置及び前記ろ過膜装で処理可能とすることを特徴とする請求項１乃至５のいずれか１項に記載の超純水製造システム。     Upstream of the ultrafiltration membrane device, an ultraviolet oxidation device, a hydrogen peroxide removal device, a degassing membrane device and a non-regenerative mixed bed ion exchange resin device are provided in this order,
    The treated water of the non-regenerative type mixed bed type ion exchange resin apparatus can be treated as treated water by the ultrafiltration membrane device and the filtration membrane device. The ultrapure water production system described in 1.
  7. 　被処理水を限外ろ過膜装置に通水して、粒子径２０ｎｍ以上の微粒子を９９．８％以上の除去率で処理し、
    　前記限外ろ過膜装置の処理水を、耐酸化剤性であり、孔径が２～４０ｎｍのろ過膜を具備するろ過膜装置に通水して処理する、
    ことを特徴とする超純水製造方法。     Water to be treated is passed through an ultrafiltration membrane device to treat fine particles having a particle diameter of 20 nm or more with a removal rate of 99.8% or more,
    The treated water of the ultrafiltration membrane device is treated by passing it through a filtration membrane device having an oxidation resistance and a filtration membrane having a pore diameter of 2 to 40 nm.
    An ultrapure water production method characterized by the above.
  8. 　前記限外ろ過膜装置の被処理水は、過酸化水素を０．１～３μｇ／Ｌ含むことを特徴とする請求項７に記載の超純水製造方法。 The method for producing ultrapure water according to claim 7, wherein the water to be treated of the ultrafiltration membrane device contains 0.1 to 3 μg / L of hydrogen peroxide.
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