WO2017145419A1 - Cleaning method for ultrapure water production system - Google Patents

Cleaning method for ultrapure water production system Download PDF

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Publication number
WO2017145419A1
WO2017145419A1 PCT/JP2016/076556 JP2016076556W WO2017145419A1 WO 2017145419 A1 WO2017145419 A1 WO 2017145419A1 JP 2016076556 W JP2016076556 W JP 2016076556W WO 2017145419 A1 WO2017145419 A1 WO 2017145419A1
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WO
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Prior art keywords
ultrapure water
cleaning
pressure
production system
water production
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PCT/JP2016/076556
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French (fr)
Japanese (ja)
Inventor
秀章 飯野
森田　博志
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栗田工業株式会社
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Priority to KR1020187023020A priority Critical patent/KR20180115692A/en
Publication of WO2017145419A1 publication Critical patent/WO2017145419A1/en

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B08—CLEANING
    • B08B—CLEANING IN GENERAL; PREVENTION OF FOULING IN GENERAL
    • B08B3/00—Cleaning by methods involving the use or presence of liquid or steam
    • B08B3/04—Cleaning involving contact with liquid
    • B08B3/08—Cleaning involving contact with liquid the liquid having chemical or dissolving effect
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B08—CLEANING
    • B08B—CLEANING IN GENERAL; PREVENTION OF FOULING IN GENERAL
    • B08B9/00—Cleaning hollow articles by methods or apparatus specially adapted thereto 
    • B08B9/02—Cleaning pipes or tubes or systems of pipes or tubes
    • B08B9/027—Cleaning the internal surfaces; Removal of blockages
    • B08B9/032—Cleaning the internal surfaces; Removal of blockages by the mechanical action of a moving fluid, e.g. by flushing
    • 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
    • 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 a cleaning method for an ultrapure water production system, and more particularly, to a pipe for an ultrapure water production system when a new ultrapure water production system is started up or when it is restarted after a certain period of inactivity.
  • the present invention relates to a cleaning method.
  • ultrapure water containing a very small amount of impurities such as organic substances, fine particles, and ionic substances has been used to clean the system.
  • the ultrapure water to be used is required to have a very high purity as the semiconductor is miniaturized and the capacity is increased.
  • the required water quality for ultrapure water used in the latest semiconductor manufacturing is: resistivity: 18.2 M ⁇ ⁇ cm or more, fine particles: 1 / mL or less, viable bacteria: 1 / L or less, TOC (Total Organic Carbon: Total organic carbon): 1 ppb or less, silica: 1 ppb or less, metals: 1 ppt or less, ions: 10 ppt or less.
  • Ultrapure water used in such semiconductor manufacturing processes is mainly manufactured in an ultrapure water production apparatus equipped with a pretreatment system, a primary pure water system, and a secondary pure water system (subsystem).
  • the pretreatment system is for turbidizing raw water using a turbidity treatment device such as coagulation filtration, microfiltration membrane (MF membrane), ultrafiltration membrane (UF membrane), etc., or a dechlorination treatment device such as activated carbon. is there.
  • the primary pure water system is for removing impurities such as ion components and TOC components contained in pretreated water by a reverse osmosis membrane (RO membrane) device, a degassing membrane device, an ion exchange tower, and the like.
  • RO membrane reverse osmosis membrane
  • Sub-systems mainly include sub-tanks that temporarily store primary pure water, heat exchangers, UV oxidation devices (UV devices), catalytic oxidant decomposition devices, deaeration devices, mixed-bed ion exchange devices, and limit Equipped with a filtration membrane device (UF device) to remove ultra-fine particles and trace ions in primary pure water, especially impurities such as low-molecular trace organics, and to produce ultrapure water with higher purity It is.
  • An ultrapure water production system equipped with such an ultrapure water production system circulates ultrapure water that has not been used at a point of use and a water supply pipe that circulates ultrapure water from the subsystem to the point of use. And a return pipe for carrying out.
  • the present invention has been made based on the above circumstances, and an ultrapure water production system capable of efficiently removing fine particles caused by impurities mixed in or generated in the ultrapure water production system.
  • the purpose is to provide a cleaning method.
  • the present invention provides at least a part of an ultrapure water production system including an ultrapure water production apparatus, a use point, and a pipe connecting the ultrapure water production apparatus and the use point.
  • a method of cleaning an ultrapure water production system having a high-pressure cleaning step of cleaning by supplying ultrapure water at a high pressure is provided (Invention 1).
  • invention 1 by supplying ultrapure water at a high pressure, fine particles adhering to the inside of the ultrapure water production system, particularly the inner wall of the pipe can be efficiently peeled and removed.
  • the cleaning operation can be performed in a short time.
  • invention 1 supply of the ultrapure water in the said high pressure washing process is performed continuously or intermittently at a pressure higher than the pressure applied at the use point, or higher than the pressure applied at the use point. It is preferable to carry out by gradually increasing the pressure (Invention 2).
  • the ultrapure water is supplied continuously or intermittently at a pressure higher than the arrival pressure at the use point, or gradually rises to a pressure higher than the arrival pressure at the use point.
  • continuous means that the pressure is higher than the pressure at the point of use, the flow rate is 0.5 m / sec or more, the washing is carried out for 0.5 hours or more, and the total flow rate is 10 times or more of the water holding amount of the pipe.
  • “Intermittent” means that the pressure is higher than the pressure applied at the point of use, and is washed intermittently at a flow rate of 0.5 m / sec or more for a total of 0.5 hours or more. Being more than 10 times the amount of water, “gradually” means cleaning at a flow rate of 0.5 m / sec or more and gradually increasing the pressure so that the final pressure is higher than the pressure at the point of use. It means to increase at a speed of 0.5 ⁇ ⁇ required increasing pressure / h and a pressure increasing rate of 10% or more.
  • PVDF polyvinylidene fluoride
  • PVDF polyvinyl chloride
  • PVDF polyvinylidene fluoride
  • Invention 3 when cleaning the ultrapure water production system, such PVDF piping wrinkles can be stretched by high-pressure cleaning, so that fine particles and the like that have entered the wrinkles can be effectively removed. it can.
  • the ultrapure water in the high-pressure washing step contains alkali, hydrogen peroxide (H 2 O 2 ), ozone or gas, or hot water (Invention 4). ).
  • the physical cleaning effect of the high-pressure cleaning step includes a chemical cleaning effect with alkali, hydrogen peroxide (H 2 O 2 ) or ozone, a physical cleaning effect with gas, and hot water. Since a sterilizing effect and the like are further added, the cleaning effect can be further improved.
  • invention 5 since the ultrapure water staying in the system after the high pressure cleaning step is pushed out of the system, the fine particles dispersed in the ultrapure water after the high pressure cleaning step are removed from the pipe. It is possible to prevent reattachment to the inner wall or the like.
  • the ultrapure water production apparatus includes an ultrafiltration membrane device (UF device), and the ultrafiltration water device (UF device) is used for cleaning the ultrapure water production system. Instead, it is preferable to install a dummy pipe or a dummy UF device having no UF function to allow water to pass through (Invention 6).
  • the dummy tube or the dummy UF device is used instead of the UF device, so that the UF device is clogged at the cleaning stage due to fine particles peeled off from the piping. Therefore, the cost for the UF device can be reduced.
  • the fine particles adhering to the ultrapure water production system, in particular, the inner wall of the pipe can be efficiently peeled and removed, so that the cleaning operation is shortened. Can be done in time.
  • FIG. 1 is a block diagram showing an ultrapure water production system used in a cleaning method for an ultrapure water production system according to an embodiment of the present invention.
  • FIG. 2 is a graph showing the relationship between the number of fine particles and the elapsed time after cleaning when the piping pressure of Example 1 is changed from 0.4 MPa to 0.7 MPa.
  • FIG. 3 is a graph showing the relationship between the number of fine particles and the elapsed time after cleaning in Example 2.
  • FIG. 4 is a graph showing the relationship between the number of fine particles and the elapsed time after cleaning in the comparative example.
  • FIG. 1 is a block diagram showing an ultrapure water production system used in a cleaning method for an ultrapure water production system according to an embodiment of the present invention.
  • the ultrapure water production system 1 shown in FIG. 1 is ultrapure from an ultrapure water production apparatus having a pretreatment system 2, a primary pure water system 3, and a secondary pure water system (subsystem) 4 in this order to a use point 5. It supplies water.
  • the raw water supplied to the pretreatment system 2 passes through the water supply pipe L1 after turbidity treatment by coagulation filtration, MF membrane (microfiltration membrane), UF membrane (ultrafiltration membrane) or dechlorination treatment by activated carbon. , Supplied to the primary pure water system 3.
  • the treated water supplied to the primary pure water system 3 is subjected to removal of impurities such as ion components and TOC components by an RO membrane (reverse osmosis membrane), a degassing membrane, an ion exchange tower, etc., and then passes through a water supply pipe L2. , Supplied to the subsystem 4.
  • impurities such as trace amounts of fine particles and trace ions in the treated water, particularly low molecular weight trace organic substances, are removed, and ultrapure water with higher purity is produced.
  • the ultrapure water produced by the subsystem 4 is sent to the use point 5 through the water supply pipe L4.
  • the sub-system 4 includes a sub-tank 41, a heat exchanger 42, an ultraviolet oxidizer (UV device) 43, a catalytic oxidizer decomposition device 44, a deaerator 45, a mixed bed ion exchanger 46, an ultrafiltration membrane device (UF device) 47 in this order.
  • the sub tank 41 is for temporarily storing treated water supplied from the primary pure water system 3.
  • the heat exchanger 42 is for adjusting the temperature of the treated water.
  • the ultraviolet oxidation device (UV device) 43 is for oxidizing and decomposing organic matter (TOC component) in water by oxidation treatment by ultraviolet irradiation.
  • the catalytic oxidant decomposition apparatus 44 is formed of H 2 generated in the ultraviolet oxidation apparatus (UV apparatus) 43 by a palladium (Pd) compound such as metal palladium, palladium oxide, palladium hydroxide, or a noble metal catalyst such as platinum (Pt). This is for decomposing and removing O 2 and other oxidizing substances.
  • the deaeration device 45 is for reducing the amount of dissolved oxygen in the treated water.
  • the mixed bed type ion exchange device 46 is for removing cations and anions in the treated water and increasing the purity of the treated water.
  • the ultrafiltration membrane device (UF device) 47 is for removing fine particles and the like of the ion exchange resin flowing out from the mixed bed type ion exchange device 46.
  • the devices constituting these subsystems 4 are connected by pipes L31-36, respectively.
  • a pump P for changing the pressure of the supplied ultrapure water is provided in the water supply pipe L31 that connects the sub tank 41 and the heat exchanger 42.
  • the pump P is also provided in a water supply pipe L ⁇ b> 35 that connects the deaeration device 45 and the mixed bed ion exchange device 46.
  • the ultrapure water production system returns the ultrapure water that has not been used at the use point 5 to the subtank 41 of the subsystem 4 in addition to the water supply pipes L1, L2, L31-36, and L4.
  • a pipe R1 and a return pipe R2 for circulating ultrapure water after passing through a dummy pipe or a dummy UF device having no UF function at the time of cleaning directly from the water supply pipe L4 to the sub tank 41 are provided.
  • the material of the water supply pipe L4 and the return pipe R1 that connect the use point 5 is polyvinylidene fluoride (PVDF).
  • PVDF is excellent in chemical resistance against chemicals such as alkali, corrosion resistance against sterilization cleaning and ultraviolet light sterilization, heat resistance against sterilization cleaning with hot water, and the like, and thus has an effect of suppressing the elution of impurities into the treated water.
  • the piping material other than the above does not need to be PVDF.
  • the object of the cleaning method of the ultrapure water production system according to this embodiment is the devices 41-47 of the subsystem 4, the water supply pipe L31-36 connecting the devices of the subsystem 4, the subsystem 4 and the use point 5 Are water supply pipe L4 and return pipes R1 and R2.
  • the particle diameter of the fine particles to be cleaned is 10 to 200 nm
  • the ultrapure water used for cleaning refers to pure water having a specific resistance value of 15 M ⁇ cm or more.
  • the high-pressure cleaning process is a process of physically removing fine particles and organic substances adhering to the inside of the ultrapure water production system, particularly the inner wall of the pipe, etc., with ultrapure water supplied at high pressure.
  • the pressure of the supplied ultrapure water is adjusted by changing the inverter of the pump P arranged in the subsystem 4 or by opening / closing a valve (not shown) installed in the piping in the subsystem 4.
  • the supplied ultrapure water preferably has a temperature of 20 to 85 ° C., a flow rate of 0.5 to 4.0 m / sec, and a flow rate of 10 times the pipe volume.
  • the timing for ending the cleaning is measured by an on-line particle monitor (not shown) installed in the return pipe R1, so that the number of particles of 20 nm or more present in the treated water is 1 / mL or less (hereinafter referred to as “steady state”). It may be called “state”.).
  • the supply of ultrapure water in the high-pressure washing process may be continuously performed at a pressure higher than the landing pressure at the use point 5.
  • the term “continuous” as used herein refers to a pressure higher than the landing pressure at the use point 5, with a flow rate of 0.5 m / sec or more, and washing for 0.5 hours or more, so that the total flow rate is at least 10 times the amount of water retained in the pipe. It is to become.
  • the landing pressure at the use point 5 is preferably 0.7 MPa or less, and the pressure of the supplied ultrapure water is preferably in the range of 0.15 MPa to 0.8 MPa.
  • the supply of ultrapure water in the high-pressure washing process may be intermittently performed at a pressure higher than the landing pressure at the use point 5.
  • the term “intermittent” as used herein is a pressure higher than the pressure applied at the use point 5 and is washed intermittently at a flow rate of 0.5 m / sec or more for a total of 0.5 hours or more.
  • the amount of water is 10 times or more.
  • the pressure at the use point 5 is preferably 0.7 MPa or less, and the normal pressure of the supplied ultrapure water is preferably in the range of 0.15 MPa to 0.8 MPa.
  • the intermittent high-pressure cleaning is preferably performed after the passage of a predetermined time, after passing water at a predetermined flow rate, or after confirming that the number of measured fine particles is in a steady state.
  • the supply of ultrapure water in the high-pressure washing process may be gradually increased to a pressure higher than the landing pressure at the use point 5.
  • “gradual” means that the flow rate is 0.5 m / sec or more and the washing is performed for 0.5 hours or more, and the total flow rate is 10 times or more of the amount of water retained in the pipe.
  • the pressure at the use point 5 is preferably 0.7 MPa or less, and the normal pressure of the supplied ultrapure water is preferably in the range of 0.15 MPa to 0.8 MPa.
  • the above-mentioned gradual high-pressure washing is preferably performed by increasing the pressure continuously or stepwise.
  • the pressure is continuously increased, it is preferably performed at a predetermined rate of increase, and when the pressure is increased stepwise, after a predetermined time has elapsed, after a predetermined flow rate of water has passed, or the number of particles measured is in a steady state. It is preferable to carry out after confirming that it has become.
  • the piping of the subsystem 4 is susceptible to sudden pressure fluctuations, so that the removal efficiency of the fine particles adhering to the piping is increased.
  • the cleaning method of the ultrapure water production system according to the present invention is not limited to the above embodiment, and the ultrapure water in the high pressure cleaning step includes alkali, hydrogen peroxide (H 2 O 2 ), ozone or gas, or Hot water may be used.
  • the ultrapure water in the high pressure cleaning step includes alkali, hydrogen peroxide (H 2 O 2 ), ozone or gas, or Hot water may be used.
  • H 2 O 2 hydrogen peroxide
  • Hot water Hot water
  • the cleaning effect by the cleaning method of the ultrapure water production system according to the present invention can be further improved.
  • the cleaning effect when the high pressure cleaning process is performed using the alkali or the like will be described.
  • alkali By using alkali, fine particles adhering to the piping of the subsystem 4 can be chemically peeled and dispersed.
  • the ultrapure water containing alkali is preferably a tetramethylammonium hydroxide aqueous solution or a solution containing any of choline, caustic soda and ammonia, and preferably has a pH of 10 or more. Further, the washing time with ultrapure water containing alkali is preferably in the range of 0.5 to 2 hours.
  • the concentration of ultrapure water containing hydrogen peroxide (H 2 O 2 ) is preferably 0.1% or more.
  • the cleaning time with ultrapure water containing hydrogen peroxide (H 2 O 2 ) is preferably in the range of 0.5 to 2 hours.
  • ozone By using ozone, the fine particles adhering to the piping of the subsystem 4 can be chemically removed by the oxidative decomposition power of ozone.
  • concentration of ultrapure water containing ozone is preferably 0.1 mg / L or more.
  • the cleaning time with ultrapure water containing ozone is preferably in the range of 0.5 to 2 hours.
  • the piping of the subsystem 4 can be sterilized and washed.
  • the temperature of hot water is preferably 60 ° C. or higher.
  • the piping of the subsystem 4 is preferably made of PVDF having excellent heat resistance.
  • cleaning method of the ultrapure water manufacturing system which concerns on this invention has the discharge process which pushes out the ultrapure water which retains in a system after the said high pressure washing process out of the system.
  • the water passing time in the discharging step is preferably in the range of 0.5 to 24 hours.
  • the combination of the high-pressure cleaning step, the alkali and the like and the discharge step in the cleaning method of the ultrapure water production system according to the present embodiment includes a high-pressure cleaning step using ultrapure water containing alkali, hydrogen peroxide (H 2 O It is preferable to perform the washing and discharging steps with ultrapure water containing 2 ) in this order. By combining in this way, the effects of both chemical cleaning with alkali and hydrogen peroxide (H 2 O 2 ) and physical cleaning with high-pressure supply of ultrapure water can be expected.
  • the high-pressure cleaning step using ultrapure water containing alkali and the cleaning using ultrapure water containing hydrogen peroxide (H 2 O 2 ) may be repeated twice in this order. By repeating the cleaning with alkali and hydrogen peroxide (H 2 O 2 ) twice, the effect of chemical cleaning is further enhanced.
  • the high-pressure cleaning step using ultrapure water containing alkali may be performed separately in the cleaning using ultrapure water containing alkali and the high-pressure cleaning step using ultrapure water. In this case, it is preferable to perform the high-pressure washing process with ultrapure water after alkali washing.
  • “after alkali cleaning” refers to after the passage of a predetermined time in cleaning with alkali, after passing water at a predetermined flow rate, or after confirming that the number of fine particle measurement is in a steady state.
  • the high-pressure washing process may be further performed during the discharging process or after the discharging process.
  • “after the discharge process” refers to after the passage of a predetermined time in the discharge process, after passing water at a predetermined flow rate, or after confirming that the number of fine particle measurement has reached a steady state.
  • the time required for cleaning by the combination as described above is 2 to 7 days.
  • the timing for ending the cleaning is measured by an on-line particle monitor (not shown) installed in the return pipe R1, so that the number of particles of 20 nm or more present in the treated water is 1 / mL or less (steady state). It is judged by whether or not.
  • a polyvinyl chloride (PVC) dummy tube (not shown) or a dummy UF device having no UF function (not shown) Not) is installed.
  • PVC polyvinyl chloride
  • Example 1 Subsystem 4 was cleaned using the ultrapure water production system shown in FIG.
  • An on-line particulate monitor manufactured by Particle Measuring Systems, product name: UDI-20
  • UDI-20 on-line particulate monitor
  • FIG. 2 shows the relationship between the pressure and the number of fine particles and the elapsed time after cleaning. As can be seen from this result, when the pressure increases, fine particles are generated. Thus, it can be seen that there is a certain effect in performing the pipe cleaning of the subsystem 4 under a high pressure condition.
  • Example 2 Two PVDF pipes with a pipe diameter of 25A were used as the return pipe R2, and two pipes were installed with a pipe length of 50 m. One was subjected to continuous high-pressure washing using ultrapure water containing alkali, and as another comparative example, the other was washed only with ultrapure water containing alkali. In each case, the water flow rate was 0.5 m / sec, and the flow rate was 3 m 3 .
  • the pressure of the return pipe R2 was 0.4 MPa for alkali cleaning + continuous high pressure cleaning (Example 2), and 0.3 MPa for only alkali cleaning (Comparative Example). The normal pressure was 0.3 MPa.
  • the number of fine particles was measured using an online fine particle monitor (UDI-20: manufactured by Particle Measuring Systems) installed in the return pipe R2.
  • FIG. 3 shows the relationship between the number of fine particles and the elapsed time after cleaning when performing continuous high-pressure cleaning using ultrapure water containing alkali (Example 2), and cleaning only with ultrapure water containing alkali.
  • the relationship between the number of fine particles and the elapsed time after cleaning is shown in FIG.
  • the number of fine particles of 20 nm or more is stabilized after 30 hours. This shows that the cleaning time is shortened when alkaline cleaning is combined with continuous high-pressure cleaning.
  • the cleaning method of the ultrapure water production system of the present invention by supplying ultrapure water at a high pressure, fine particles adhering to the inside of the ultrapure water production system, in particular, the inner wall of the pipe are removed. Since it can peel and remove efficiently, a cleaning operation can be performed in a short time.
  • the high-pressure cleaning process is performed with ultrapure water containing alkali, the chemical cleaning effect due to alkali is added to the physical cleaning effect of supplying ultrapure water at a high pressure, so that ultrapure water is more effective. Cleaning in the water production system can be performed.
  • the present invention eliminates impurities mixed or generated in the system when the ultrapure water production system is newly started up or when it is restarted after a certain period of operation stoppage. It is useful as a method for cleaning the system until it meets the required water quality.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Mechanical Engineering (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Hydrology & Water Resources (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Environmental & Geological Engineering (AREA)
  • Water Supply & Treatment (AREA)
  • Organic Chemistry (AREA)
  • Cleaning In General (AREA)
  • Cleaning By Liquid Or Steam (AREA)
  • Separation Using Semi-Permeable Membranes (AREA)
  • Cleaning Or Drying Semiconductors (AREA)

Abstract

In the present invention, ultrapure water is supplied at high pressure to at least part of an ultrapure water production system (1), which is provided with an ultrapure water production device (4), a point of use (5), and pipes connecting the ultrapure water production device (4) and point of use (5), thereby breaking fine particles and organic matter adhering to the inside of the ultrapure water production system (1), in particular, the inside walls of the pipes and the like, so as to physically clean and remove the same. With this cleaning method for the ultrapure water production system (1), it is possible to efficiently eliminate impurities such as organic matter, fine particles, and ionic substances mixed in or generated in the ultrapure water production system (1).

Description

超純水製造システムの洗浄方法Cleaning method of ultrapure water production system
　本発明は、超純水製造システムの洗浄方法に関し、特に、超純水製造システムを新規に立ち上げた場合や一定期間稼働を休止した後に再立ち上げした場合の超純水製造システムの配管の洗浄方法に関する。 The present invention relates to a cleaning method for an ultrapure water production system, and more particularly, to a pipe for an ultrapure water production system when a new ultrapure water production system is started up or when it is restarted after a certain period of inactivity. The present invention relates to a cleaning method.
　従来、半導体や液晶パネル等の電子機器製造の分野では、システムを洗浄するために、有機物、微粒子、イオン性物質等の不純物の含有量が極めて小さい超純水が使用されている。中でも、半導体の製造工程においては、半導体の微細化・大容量化にともない、使用する超純水には非常に高い純度が求められる。例えば、最新の半導体製造に使用する超純水に対する要求水質は、抵抗率： １８．２ＭΩ・ｃｍ以上、微粒子：１個／ｍＬ以下、生菌：１個／Ｌ以下、ＴＯＣ（Ｔｏｔａｌ　Ｏｒｇａｎｉｃ　Ｃａｒｂｏｎ：全有機炭素）：１ｐｐｂ以下、シリカ：１ｐｐｂ以下、金属類：１ｐｐｔ以下、イオン類：１０ｐｐｔ以下である。 Conventionally, in the field of manufacturing electronic devices such as semiconductors and liquid crystal panels, ultrapure water containing a very small amount of impurities such as organic substances, fine particles, and ionic substances has been used to clean the system. In particular, in the semiconductor manufacturing process, the ultrapure water to be used is required to have a very high purity as the semiconductor is miniaturized and the capacity is increased. For example, the required water quality for ultrapure water used in the latest semiconductor manufacturing is: resistivity: 18.2 MΩ · cm or more, fine particles: 1 / mL or less, viable bacteria: 1 / L or less, TOC (Total Organic Carbon: Total organic carbon): 1 ppb or less, silica: 1 ppb or less, metals: 1 ppt or less, ions: 10 ppt or less.
　このような半導体の製造工程に使用される超純水は、主に、前処理システム、一次純水システム、二次純水システム（サブシステム）を備える超純水製造装置において製造され、ユースポイントに供給される。前処理システムは、凝集濾過、精密濾過膜（ＭＦ膜）、限外濾過膜（ＵＦ膜）等による除濁処理装置や活性炭等による脱塩素処理装置を用いて原水を除濁するためのものである。一次純水システムは、逆浸透膜（ＲＯ膜）装置、脱気膜装置、イオン交換塔等により、前処理水に含まれるイオン成分やＴＯＣ成分等の不純物を除去するためのものである。サブシステムは、主に一次純水を一時的に貯留するサブタンク、熱交換器、紫外線酸化装置（ＵＶ装置）、触媒式酸化性物質分解装置、脱気装置、混床式イオン交換装置、限外濾過膜装置（ＵＦ装置）を備え、一次純水中の極微量の微粒子や微量イオン、特に低分子の微量有機物のような不純物を除去し、より純度の高い超純水を製造するためのものである。このような超純水製造装置を備える超純水製造システムは、サブシステムからユースポイントへ超純水を流通する送水配管と、ユースポイントで使用されなかった超純水をサブシステムのサブタンクへ循環するための返送配管とを備える。 Ultrapure water used in such semiconductor manufacturing processes is mainly manufactured in an ultrapure water production apparatus equipped with a pretreatment system, a primary pure water system, and a secondary pure water system (subsystem). To be supplied. The pretreatment system is for turbidizing raw water using a turbidity treatment device such as coagulation filtration, microfiltration membrane (MF membrane), ultrafiltration membrane (UF membrane), etc., or a dechlorination treatment device such as activated carbon. is there. The primary pure water system is for removing impurities such as ion components and TOC components contained in pretreated water by a reverse osmosis membrane (RO membrane) device, a degassing membrane device, an ion exchange tower, and the like. Sub-systems mainly include sub-tanks that temporarily store primary pure water, heat exchangers, UV oxidation devices (UV devices), catalytic oxidant decomposition devices, deaeration devices, mixed-bed ion exchange devices, and limit Equipped with a filtration membrane device (UF device) to remove ultra-fine particles and trace ions in primary pure water, especially impurities such as low-molecular trace organics, and to produce ultrapure water with higher purity It is. An ultrapure water production system equipped with such an ultrapure water production system circulates ultrapure water that has not been used at a point of use and a water supply pipe that circulates ultrapure water from the subsystem to the point of use. And a return pipe for carrying out.
　通常、上記のような超純水製造システムを新規に立ち上げた場合や一定期間稼働を休止した後に再立ち上げした場合には、システム内に有機物、微粒子、イオン性物質等の不純物が混入又は発生するため、これらの不純物を除去してユースポイントにおける超純水が要求水質を満たすようになるまで、システムの洗浄を行う。中でも、工場の新設に伴い、超純水製造システムを新規に立ち上げる場合には、施行時に配管の内壁等に微粒子や有機物が付着するため、システムの洗浄に多くの時間を要し、工業の稼働効率が低下する。 In general, when a new ultrapure water production system such as the one described above is started up or when it is restarted after being suspended for a certain period of time, impurities such as organic substances, fine particles, and ionic substances are mixed in the system. Therefore, the system is cleaned until these impurities are removed and the ultrapure water at the use point satisfies the required water quality. In particular, when a new ultrapure water production system is started up due to the establishment of a new factory, fine particles and organic substances adhere to the inner wall of the pipe during the operation, so it takes a lot of time to clean the system. Operating efficiency is reduced.
　上述のようなシステム内に混入又は発生した不純物の洗浄方法としては、例えば、特許文献１に、超純水製造装置の立ち上げ時の洗浄方法として、圧縮ガスと超純水とを交互に供給することで配管の内壁を洗浄する方法が提案されている。 As a cleaning method for impurities mixed in or generated in the system as described above, for example, in Patent Document 1, compressed gas and ultrapure water are alternately supplied as a cleaning method when the ultrapure water production apparatus is started up. Thus, a method for cleaning the inner wall of the pipe has been proposed.
特開２００４－０５００４８号公報JP 2004-050048 A
　超純水製造装置の配管の内壁等に付着している微粒子は、突発的な圧力変動によって配管の内壁等から剥離することがわかっており、特許文献１では、このような微粒子の剥離を早めるために、圧縮ガスと超純水を併用して洗浄を行っている。しかしながら、配管が受ける圧力を変動させるためにガスを使用しているため、配管内のデッドスペースに溶存ガスが残ってしまうことにより、製造される超純水の純度の低下を招く可能性がある。よって、この溶存ガスの除去にさらに時間を要するため、超純水製造システムの洗浄を短時間で行うことが難しくなるといった問題がある。 It is known that the fine particles adhering to the inner wall of the pipe of the ultrapure water production apparatus are peeled off from the inner wall of the pipe due to a sudden pressure fluctuation. For this purpose, cleaning is performed using compressed gas and ultrapure water in combination. However, since gas is used to fluctuate the pressure received by the piping, the dissolved gas may remain in the dead space in the piping, which may lead to a decrease in the purity of the manufactured ultrapure water. . Therefore, since it takes more time to remove the dissolved gas, there is a problem that it is difficult to clean the ultrapure water production system in a short time.
　本発明は上述のような事情に基づいてなされたものであり、超純水製造システム内に混入又はシステム内で発生した不純物に起因する微粒子を効率的に除去することのできる超純水製造システムの洗浄方法の提供を目的とする。 The present invention has been made based on the above circumstances, and an ultrapure water production system capable of efficiently removing fine particles caused by impurities mixed in or generated in the ultrapure water production system. The purpose is to provide a cleaning method.
　上記課題を解決するために、第一に本発明は、超純水製造装置、ユースポイント及び前記超純水製造装置と前記ユースポイントとを接続する配管を備える超純水製造システムの少なくとも一部を洗浄する方法であって、超純水を高圧で供給することにより洗浄する高圧洗浄工程を有する超純水製造システムの洗浄方法を提供する（発明１）。 In order to solve the above problems, firstly, the present invention provides at least a part of an ultrapure water production system including an ultrapure water production apparatus, a use point, and a pipe connecting the ultrapure water production apparatus and the use point. A method of cleaning an ultrapure water production system having a high-pressure cleaning step of cleaning by supplying ultrapure water at a high pressure is provided (Invention 1).
　かかる発明（発明１）によれば、超純水を高圧供給することによって、超純水製造システム内、特に配管の内壁等に付着している微粒子を効率的に剥離、除去することができるので、洗浄作業を短時間で行うことができる。 According to this invention (Invention 1), by supplying ultrapure water at a high pressure, fine particles adhering to the inside of the ultrapure water production system, particularly the inner wall of the pipe can be efficiently peeled and removed. The cleaning operation can be performed in a short time.
　上記発明（発明１）においては、前記高圧洗浄工程における超純水の供給を、前記ユースポイントにおける着圧よりも高い圧力で連続的もしくは間欠的に行う、又は前記ユースポイントにおける着圧よりも高い圧力まで漸次的に上昇させて行うことが好ましい（発明２）。 In the said invention (invention 1), supply of the ultrapure water in the said high pressure washing process is performed continuously or intermittently at a pressure higher than the pressure applied at the use point, or higher than the pressure applied at the use point. It is preferable to carry out by gradually increasing the pressure (Invention 2).
　かかる発明（発明２）によれば、ユースポイントにおける着圧よりも高い圧力で連続的もしくは間欠的に超純水を供給することにより、又はユースポイントにおける着圧よりも高い圧力まで漸次的に上昇させて超純水の供給を行うことにより、発生する乱流等によって、効果的に超純水製造システムの配管の内壁等に付着している微粒子を除去することが可能となる。なお、本発明の「連続的」とは、ユースポイントにおける着圧よりも高い圧力で、流速０．５ｍ／ｓｅｃ以上で、０．５時間以上洗浄し、総合流量が配管保有水量の１０倍以上になること、「間欠的」とは、ユースポイントにおける着圧よりも高い圧力で、流速０．５ｍ／ｓｅｃ以上で間欠的に、総合して０．５時間以上洗浄し、総合流量が配管保有水量の１０倍以上になること、「漸次的」とは、流速０．５ｍ／ｓｅｃ以上で洗浄し、最終的にユースポイントにおける着圧よりも高い圧力になるよう漸次的に圧力を、圧力上昇速度０．５×△必要上昇圧力／ｈ、圧力上昇率１０％以上で、上昇させることをいう。 According to this invention (Invention 2), the ultrapure water is supplied continuously or intermittently at a pressure higher than the arrival pressure at the use point, or gradually rises to a pressure higher than the arrival pressure at the use point. By supplying ultrapure water in this way, it is possible to effectively remove the fine particles adhering to the inner wall of the pipe of the ultrapure water production system due to the generated turbulent flow or the like. In the present invention, “continuous” means that the pressure is higher than the pressure at the point of use, the flow rate is 0.5 m / sec or more, the washing is carried out for 0.5 hours or more, and the total flow rate is 10 times or more of the water holding amount of the pipe. “Intermittent” means that the pressure is higher than the pressure applied at the point of use, and is washed intermittently at a flow rate of 0.5 m / sec or more for a total of 0.5 hours or more. Being more than 10 times the amount of water, “gradually” means cleaning at a flow rate of 0.5 m / sec or more and gradually increasing the pressure so that the final pressure is higher than the pressure at the point of use. It means to increase at a speed of 0.5 × Δrequired increasing pressure / h and a pressure increasing rate of 10% or more.
　上記発明（発明１，２）においては、前記配管の少なくとも一部がポリフッ化ビニリデン（ＰＶＤＦ）からなることが好ましい（発明３）。 In the above inventions (Inventions 1 and 2), it is preferable that at least a part of the piping is made of polyvinylidene fluoride (PVDF) (Invention 3).
　超純水製造システムの配管材料としては、超純水への溶出物質や施工時の汚れ持ち込みが少ないことを考慮し、ポリ塩化ビニル（ＰＶＣ）やポリフッ化ビニリデン（ＰＶＤＦ）等が用いられる。中でも、ＰＶＤＦは、その優れた耐食性や耐熱性から配管材料として好適に用いられるが、加工過程における熱シワや施工過程における搬送シワ等の歪みが発生することがあり、このようなシワには、微粒子等の不純物が入り込み易い。かかる発明（発明３）によれば、超純水製造システムの洗浄時に、高圧洗浄によってこのようなＰＶＤＦ配管のシワを伸ばすことができるため、シワに入り込んだ微粒子等を効果的に除去することができる。 As the piping material of the ultrapure water production system, polyvinyl chloride (PVC), polyvinylidene fluoride (PVDF), or the like is used in consideration of the eluent in ultrapure water and the small amount of dirt brought in during construction. Among them, PVDF is suitably used as a piping material because of its excellent corrosion resistance and heat resistance, but distortion such as heat wrinkles in the processing process and conveyance wrinkles in the construction process may occur. Impurities such as fine particles easily enter. According to this invention (Invention 3), when cleaning the ultrapure water production system, such PVDF piping wrinkles can be stretched by high-pressure cleaning, so that fine particles and the like that have entered the wrinkles can be effectively removed. it can.
　上記発明（発明１－３）においては、前記高圧洗浄工程における超純水が、アルカリ、過酸化水素（Ｈ２Ｏ２）、オゾンもしくは気体を含む、又は熱水であることが好ましい（発明４）。 In the above invention (Invention 1-3), it is preferable that the ultrapure water in the high-pressure washing step contains alkali, hydrogen peroxide (H 2 O 2 ), ozone or gas, or hot water (Invention 4). ).
　かかる発明（発明４）によれば、上記高圧洗浄工程の物理的洗浄効果に、アルカリ、過酸化水素（Ｈ２Ｏ２）又はオゾンによる化学的洗浄効果、気体による物理的洗浄効果、熱水による殺菌効果等がさらに加えられるため、洗浄効果をより優れたものとすることができる。 According to this invention (Invention 4), the physical cleaning effect of the high-pressure cleaning step includes a chemical cleaning effect with alkali, hydrogen peroxide (H 2 O 2 ) or ozone, a physical cleaning effect with gas, and hot water. Since a sterilizing effect and the like are further added, the cleaning effect can be further improved.
　上記発明（発明１－４）においては、前記高圧洗浄工程後に系内に滞留している超純水を系外に押し出す排出工程を有することが好ましい（発明５）。 In the above invention (Invention 1-4), it is preferable to have a discharge step of pushing out ultrapure water remaining in the system after the high-pressure washing step (Invention 5).
　かかる発明（発明５）によれば、上記高圧洗浄工程後に系内に滞留している超純水が系外に押し出されるため、高圧洗浄工程後の超純水に分散している微粒子が配管の内壁等に再付着することを防ぐことができる。 According to this invention (invention 5), since the ultrapure water staying in the system after the high pressure cleaning step is pushed out of the system, the fine particles dispersed in the ultrapure water after the high pressure cleaning step are removed from the pipe. It is possible to prevent reattachment to the inner wall or the like.
　上記発明（発明１－５）においては、前記超純水製造装置が限外ろ過膜装置（ＵＦ装置）を備え、前記超純水製造システムの洗浄時には、前記限外ろ過膜装置（ＵＦ装置）に代えて、ダミー管又はＵＦ機能を有しないダミーＵＦ装置を設置して通水することが好ましい（発明６）。 In the above invention (Invention 1-5), the ultrapure water production apparatus includes an ultrafiltration membrane device (UF device), and the ultrafiltration water device (UF device) is used for cleaning the ultrapure water production system. Instead, it is preferable to install a dummy pipe or a dummy UF device having no UF function to allow water to pass through (Invention 6).
　かかる発明（発明６）によれば、超純水製造システムの洗浄時に、ＵＦ装置に代えてダミー管又はダミーＵＦ装置を用いることにより、配管等から剥離した微粒子により洗浄段階でＵＦ装置が目詰まりしてしまうことを防ぐことができるので、ＵＦ装置にかかるコストを削減することができる。 According to this invention (invention 6), when the ultrapure water production system is cleaned, the dummy tube or the dummy UF device is used instead of the UF device, so that the UF device is clogged at the cleaning stage due to fine particles peeled off from the piping. Therefore, the cost for the UF device can be reduced.
　本発明の超純水製造システムの洗浄方法によれば、超純水製造システム内、特に配管の内壁等に付着している微粒子を効率的に剥離、除去することができるので、洗浄作業を短時間で行うことができる。 According to the cleaning method of the ultrapure water production system of the present invention, the fine particles adhering to the ultrapure water production system, in particular, the inner wall of the pipe can be efficiently peeled and removed, so that the cleaning operation is shortened. Can be done in time.
図１は、本発明の一実施形態に係る超純水製造システムの洗浄方法に用いる超純水製造システムを示すブロック図である。FIG. 1 is a block diagram showing an ultrapure water production system used in a cleaning method for an ultrapure water production system according to an embodiment of the present invention. 図２は、実施例１の配管圧力を０．４ＭＰａから０．７ＭＰａへ変更した場合の微粒子数と洗浄後経過時間の関係を示す図である。FIG. 2 is a graph showing the relationship between the number of fine particles and the elapsed time after cleaning when the piping pressure of Example 1 is changed from 0.4 MPa to 0.7 MPa. 図３は、実施例２の微粒子数と洗浄後経過時間の関係を示す図である。FIG. 3 is a graph showing the relationship between the number of fine particles and the elapsed time after cleaning in Example 2. 図４は、比較例の微粒子数と洗浄後経過時間の関係を示す図である。FIG. 4 is a graph showing the relationship between the number of fine particles and the elapsed time after cleaning in the comparative example.
　以下、本発明の超純水製造システムの洗浄方法の実施の形態について、適宜図面を参照して説明する。以下に説明する実施形態は、本発明の理解を容易にするためのものであって、何ら本発明を限定するものではない。 Hereinafter, embodiments of the cleaning method of the ultrapure water production system of the present invention will be described with reference to the drawings as appropriate. The embodiment described below is for facilitating the understanding of the present invention, and does not limit the present invention.
　［超純水製造システム］
　図１は、本発明の一実施形態に係る超純水製造システムの洗浄方法に用いる超純水製造システムを示すブロック図である。図１に示す超純水製造システム１は、前処理システム２、一次純水システム３、二次純水システム（サブシステム）４をこの順に備える超純水製造装置から、ユースポイント５へ超純水を供給するものである。前処理システム２に供給された原水は、凝集濾過、ＭＦ膜（精密濾過膜）、ＵＦ膜（限外濾過膜）等による除濁処理や活性炭等による脱塩素処理の後、送水配管Ｌ１を経て、一次純水システム３へ供給される。一次純水システム３に供給された処理水は、ＲＯ膜（逆浸透膜）、脱気膜、イオン交換塔等により、イオン成分やＴＯＣ成分等の不純物を除去された後、送水配管Ｌ２を経て、サブシステム４へ供給される。サブシステム４では、処理水中の極微量の微粒子や微量イオン、特に低分子の微量有機物のような不純物が除去され、より純度の高い超純水が製造される。サブシステム４で製造された超純水は、送水配管Ｌ４を経て、ユースポイント５へ送られる。 [Ultrapure water production system]
FIG. 1 is a block diagram showing an ultrapure water production system used in a cleaning method for an ultrapure water production system according to an embodiment of the present invention. The ultrapure water production system 1 shown in FIG. 1 is ultrapure from an ultrapure water production apparatus having a pretreatment system 2, a primary pure water system 3, and a secondary pure water system (subsystem) 4 in this order to a use point 5. It supplies water. The raw water supplied to the pretreatment system 2 passes through the water supply pipe L1 after turbidity treatment by coagulation filtration, MF membrane (microfiltration membrane), UF membrane (ultrafiltration membrane) or dechlorination treatment by activated carbon. , Supplied to the primary pure water system 3. The treated water supplied to the primary pure water system 3 is subjected to removal of impurities such as ion components and TOC components by an RO membrane (reverse osmosis membrane), a degassing membrane, an ion exchange tower, etc., and then passes through a water supply pipe L2. , Supplied to the subsystem 4. In the subsystem 4, impurities such as trace amounts of fine particles and trace ions in the treated water, particularly low molecular weight trace organic substances, are removed, and ultrapure water with higher purity is produced. The ultrapure water produced by the subsystem 4 is sent to the use point 5 through the water supply pipe L4.
　サブシステム４は、サブタンク４１、熱交換器４２、紫外線酸化装置（ＵＶ装置）４３、触媒式酸化性物質分解装置４４、脱気装置４５、混床式イオン交換装置４６、限外ろ過膜装置（ＵＦ装置）４７をこの順に備えている。サブタンク４１は、一次純水システム３から供給される処理水を一時的に貯留するためのものである。熱交換器４２は、処理水の温度調節を行うためのものである。紫外線酸化装置（ＵＶ装置）４３は、紫外線照射による酸化処理により、水中の有機物（ＴＯＣ成分）を酸化分解するためのものである。触媒式酸化性物質分解装置４４は、金属パラジウム、酸化パラジウム、水酸化パラジウム等のパラジウム（Ｐｄ）化合物又は白金（Ｐｔ）などの貴金属触媒により、紫外線酸化装置（ＵＶ装置）４３で発生したＨ２Ｏ２、その他の酸化性物質を分解除去するためのものである。脱気装置４５は、処理水中の溶存酸素量を低減するためのものである。混床式イオン交換装置４６は、処理水中のカチオン及びアニオンを除去し、処理水の純度を高めるためのものである。限外ろ過膜装置（ＵＦ装置）４７は、混床式イオン交換装置４６から流出したイオン交換樹脂の微粒子等を除去するためのものである。これらサブシステム４を構成する装置は、配管Ｌ３１－３６によってそれぞれ接続されている。 The sub-system 4 includes a sub-tank 41, a heat exchanger 42, an ultraviolet oxidizer (UV device) 43, a catalytic oxidizer decomposition device 44, a deaerator 45, a mixed bed ion exchanger 46, an ultrafiltration membrane device ( UF device) 47 in this order. The sub tank 41 is for temporarily storing treated water supplied from the primary pure water system 3. The heat exchanger 42 is for adjusting the temperature of the treated water. The ultraviolet oxidation device (UV device) 43 is for oxidizing and decomposing organic matter (TOC component) in water by oxidation treatment by ultraviolet irradiation. The catalytic oxidant decomposition apparatus 44 is formed of H 2 generated in the ultraviolet oxidation apparatus (UV apparatus) 43 by a palladium (Pd) compound such as metal palladium, palladium oxide, palladium hydroxide, or a noble metal catalyst such as platinum (Pt). This is for decomposing and removing O 2 and other oxidizing substances. The deaeration device 45 is for reducing the amount of dissolved oxygen in the treated water. The mixed bed type ion exchange device 46 is for removing cations and anions in the treated water and increasing the purity of the treated water. The ultrafiltration membrane device (UF device) 47 is for removing fine particles and the like of the ion exchange resin flowing out from the mixed bed type ion exchange device 46. The devices constituting these subsystems 4 are connected by pipes L31-36, respectively.
　本実施形態において、サブタンク４１と熱交換器４２とを接続する送水配管Ｌ３１には、供給される超純水の圧力を変更するためのポンプＰが設けられている。ポンプＰは、脱気装置４５と混床式イオン交換装置４６とを接続する送水配管Ｌ３５にも設けられている。 In this embodiment, a pump P for changing the pressure of the supplied ultrapure water is provided in the water supply pipe L31 that connects the sub tank 41 and the heat exchanger 42. The pump P is also provided in a water supply pipe L <b> 35 that connects the deaeration device 45 and the mixed bed ion exchange device 46.
　本実施形態の超純水製造システムは、送水配管Ｌ１、Ｌ２、Ｌ３１－３６、Ｌ４に加えて、ユースポイント５で使用されなかった超純水をサブシステム４のサブタンク４１へ循環するための返送配管Ｒ１と、洗浄時にダミー管又はＵＦ機能を有しないダミーＵＦ装置を通過した後の超純水を送水配管Ｌ４から直接サブタンク４１へ循環するための返送配管Ｒ２とを備える。 The ultrapure water production system according to the present embodiment returns the ultrapure water that has not been used at the use point 5 to the subtank 41 of the subsystem 4 in addition to the water supply pipes L1, L2, L31-36, and L4. A pipe R1 and a return pipe R2 for circulating ultrapure water after passing through a dummy pipe or a dummy UF device having no UF function at the time of cleaning directly from the water supply pipe L4 to the sub tank 41 are provided.
　サブシステム４からユースポイント５へ送られる処理水には純度が求められるため、混床式イオン交換装置４６と限外ろ過膜装置（ＵＦ装置）４７とを接続する送水配管Ｌ３６、サブシステム４とユースポイント５とを接続する送水配管Ｌ４及び返送配管Ｒ１の材料は、ポリフッ化ビニリデン（ＰＶＤＦ）である。ＰＶＤＦは、アルカリ等の薬液に対する耐薬品性、殺菌洗浄や紫外線による殺菌に対する耐食性、熱水による殺菌洗浄に対する耐熱性等に優れるため、処理水中への不純物の溶出が抑えられるという効果がある。一方、混床式イオン交換装置４６より前段においては求められる処理水の純度がそれほど高くないことから、上記以外の配管の材料はＰＶＤＦである必要はない。 Since the purity of the treated water sent from the subsystem 4 to the use point 5 is required, the water supply pipe L36 connecting the mixed bed type ion exchange device 46 and the ultrafiltration membrane device (UF device) 47, the subsystem 4 and The material of the water supply pipe L4 and the return pipe R1 that connect the use point 5 is polyvinylidene fluoride (PVDF). PVDF is excellent in chemical resistance against chemicals such as alkali, corrosion resistance against sterilization cleaning and ultraviolet light sterilization, heat resistance against sterilization cleaning with hot water, and the like, and thus has an effect of suppressing the elution of impurities into the treated water. On the other hand, since the purity of the treated water required before the mixed bed type ion exchanger 46 is not so high, the piping material other than the above does not need to be PVDF.
　［超純水製造システムの洗浄方法］
　次に、上述したような実施形態の超純水製造システムを用いた洗浄方法について説明する。本実施形態に係る超純水製造システムの洗浄方法の対象は、サブシステム４の各装置４１－４７、サブシステム４の各装置を接続する送水配管Ｌ３１－３６、サブシステム４とユースポイント５とを接続する送水配管Ｌ４、返送配管Ｒ１及びＲ２である。本実施形態において、洗浄対象となる微粒子の粒子径は、１０～２００ｎｍであり、洗浄に用いる超純水とは、比抵抗値が１５ＭΩｃｍ以上の純水を指す。 [Cleaning method of ultrapure water production system]
Next, a cleaning method using the ultrapure water production system of the embodiment as described above will be described. The object of the cleaning method of the ultrapure water production system according to this embodiment is the devices 41-47 of the subsystem 4, the water supply pipe L31-36 connecting the devices of the subsystem 4, the subsystem 4 and the use point 5 Are water supply pipe L4 and return pipes R1 and R2. In the present embodiment, the particle diameter of the fine particles to be cleaned is 10 to 200 nm, and the ultrapure water used for cleaning refers to pure water having a specific resistance value of 15 MΩcm or more.
　＜高圧洗浄工程＞
　高圧洗浄工程は、高圧で供給される超純水により、超純水製造システム内、特に配管の内壁等に付着している微粒子や有機物を発塵させて、物理的に除去する工程である。供給される超純水の圧力は、サブシステム４内に配置されるポンプＰのインバータを変更することによって、又はサブシステム４内の配管に設置されるバルブ（図示しない）の開閉によって調節する。 <High pressure cleaning process>
The high-pressure cleaning process is a process of physically removing fine particles and organic substances adhering to the inside of the ultrapure water production system, particularly the inner wall of the pipe, etc., with ultrapure water supplied at high pressure. The pressure of the supplied ultrapure water is adjusted by changing the inverter of the pump P arranged in the subsystem 4 or by opening / closing a valve (not shown) installed in the piping in the subsystem 4.
　供給される超純水は、温度が２０～８５℃、流速が０．５～４．０ｍ／ｓｅｃ、流量が配管容積の１０倍であることが好ましい。上述の条件で、超純水を供給することにより、効率的に微粒子等を除去することができる。なお、洗浄を終了するタイミングは、返送配管Ｒ１に設置されるオンライン微粒子モニター（図示しない）で計測することにより、処理水に存在する２０ｎｍ以上の微粒子数が１個／ｍＬ以下（以下、「定常状態」と称す場合がある。）になっているかどうかで判断される。 The supplied ultrapure water preferably has a temperature of 20 to 85 ° C., a flow rate of 0.5 to 4.0 m / sec, and a flow rate of 10 times the pipe volume. By supplying ultrapure water under the above-described conditions, fine particles and the like can be efficiently removed. The timing for ending the cleaning is measured by an on-line particle monitor (not shown) installed in the return pipe R1, so that the number of particles of 20 nm or more present in the treated water is 1 / mL or less (hereinafter referred to as “steady state”). It may be called “state”.).
　高圧洗浄工程における超純水の供給は、ユースポイント５における着圧よりも高い圧力で連続的に行ってもよい。ここでいう「連続的」とは、ユースポイント５における着圧よりも高い圧力で、流速０．５ｍ／ｓｅｃ以上で、０．５時間以上洗浄し、総合流量が配管保有水量の１０倍以上になることである。この場合、ユースポイント５における着圧は０．７ＭＰａ以下であることが好ましく、供給される超純水の圧力は０．１５ＭＰａ～０．８ＭＰａの範囲であることが好ましい。上述の条件で、超純水を供給することにより、通常の通水では剥がれにくい超純水製造システムの配管の内壁等に付着している微粒子をも容易に剥離、除去することができる。 The supply of ultrapure water in the high-pressure washing process may be continuously performed at a pressure higher than the landing pressure at the use point 5. The term “continuous” as used herein refers to a pressure higher than the landing pressure at the use point 5, with a flow rate of 0.5 m / sec or more, and washing for 0.5 hours or more, so that the total flow rate is at least 10 times the amount of water retained in the pipe. It is to become. In this case, the landing pressure at the use point 5 is preferably 0.7 MPa or less, and the pressure of the supplied ultrapure water is preferably in the range of 0.15 MPa to 0.8 MPa. By supplying ultrapure water under the above-mentioned conditions, the fine particles adhering to the inner wall of the pipe of the ultrapure water production system that is difficult to be peeled off by normal water flow can be easily peeled and removed.
　高圧洗浄工程における超純水の供給は、ユースポイント５における着圧よりも高い圧力で間欠的に行ってもよい。ここでいう「間欠的」とは、ユースポイント５における着圧よりも高い圧力で、流速０．５ｍ／ｓｅｃ以上で間欠的に、総合して０．５時間以上洗浄し、総合流量が配管保有水量の１０倍以上になることである。この場合、ユースポイント５における着圧は０．７ＭＰａ以下であることが好ましく、供給される超純水の通常の圧力は０．１５ＭＰａ～０．８ＭＰａの範囲であることが好ましい。上述の条件で、超純水を供給することにより、発生する乱流等によって、効果的に超純水製造システムの配管の内壁等に付着している微粒子を除去することが可能となる。 The supply of ultrapure water in the high-pressure washing process may be intermittently performed at a pressure higher than the landing pressure at the use point 5. The term “intermittent” as used herein is a pressure higher than the pressure applied at the use point 5 and is washed intermittently at a flow rate of 0.5 m / sec or more for a total of 0.5 hours or more. The amount of water is 10 times or more. In this case, the pressure at the use point 5 is preferably 0.7 MPa or less, and the normal pressure of the supplied ultrapure water is preferably in the range of 0.15 MPa to 0.8 MPa. By supplying ultrapure water under the above-described conditions, it is possible to effectively remove fine particles adhering to the inner wall of the pipe of the ultrapure water production system due to the generated turbulent flow or the like.
　上記間欠的な高圧洗浄は、所定時間の経過後、所定流量の通水後又は微粒子計測数が定常状態になったことを確認後に行うのが好ましい。このように間欠的な高圧洗浄を行うことで、サブシステム４の配管等が、突発的な圧力変動を受け易くなるので、配管等に付着している微粒子の除去効率が高まる。 The intermittent high-pressure cleaning is preferably performed after the passage of a predetermined time, after passing water at a predetermined flow rate, or after confirming that the number of measured fine particles is in a steady state. By performing intermittent high-pressure cleaning in this manner, the piping of the subsystem 4 is susceptible to sudden pressure fluctuations, so that the removal efficiency of fine particles adhering to the piping and the like is increased.
　高圧洗浄工程における超純水の供給は、ユースポイント５における着圧よりも高い圧力まで漸次的に上昇させて行ってもよい。ここでいう「漸次的」とは、流速０．５ｍ／ｓｅｃ以上で、０．５時間以上洗浄し、総合流量が配管保有水量の１０倍以上になることである。この場合、ユースポイント５における着圧は０．７ＭＰａ以下であることが好ましく、供給される超純水の通常の圧力は０．１５ＭＰａ～０．８ＭＰａの範囲であることが好ましい。上述の条件で、超純水を供給することにより、発生する乱流等によって、効果的に超純水製造システムの配管の内壁等に付着している微粒子を除去することが可能となる。 The supply of ultrapure water in the high-pressure washing process may be gradually increased to a pressure higher than the landing pressure at the use point 5. Here, “gradual” means that the flow rate is 0.5 m / sec or more and the washing is performed for 0.5 hours or more, and the total flow rate is 10 times or more of the amount of water retained in the pipe. In this case, the pressure at the use point 5 is preferably 0.7 MPa or less, and the normal pressure of the supplied ultrapure water is preferably in the range of 0.15 MPa to 0.8 MPa. By supplying ultrapure water under the above-described conditions, it is possible to effectively remove fine particles adhering to the inner wall of the pipe of the ultrapure water production system due to the generated turbulent flow or the like.
　上記漸次的な高圧洗浄は、連続的又は段階的に圧力を上昇させて行うことが好ましい。連続的に圧力を上昇させる場合は、所定の上昇速度で行うことが好ましく、段階的に圧力を上昇させる場合は、所定時間の経過後、所定流量の通水後又は微粒子計測数が定常状態になったことを確認後に行うのが好ましい。このように漸次的な高圧洗浄を行うことで、サブシステム４の配管等が、突発的な圧力変動を受け易くなるので、配管等に付着している微粒子の除去効率が高まる。 The above-mentioned gradual high-pressure washing is preferably performed by increasing the pressure continuously or stepwise. When the pressure is continuously increased, it is preferably performed at a predetermined rate of increase, and when the pressure is increased stepwise, after a predetermined time has elapsed, after a predetermined flow rate of water has passed, or the number of particles measured is in a steady state. It is preferable to carry out after confirming that it has become. By performing the gradual high-pressure cleaning in this manner, the piping of the subsystem 4 is susceptible to sudden pressure fluctuations, so that the removal efficiency of the fine particles adhering to the piping is increased.
　本発明に係る超純水製造システムの洗浄方法は上記実施形態に限定されず、上記高圧洗浄工程における超純水が、アルカリ、過酸化水素（Ｈ２Ｏ２）、オゾンもしくは気体を含む、又は熱水であってもよい。このように超純水とアルカリ等を組み合わせて洗浄を行うことにより、超純水による高圧洗浄工程の物理的洗浄効果に、アルカリ等による化学的洗浄効果や気体による物理的洗浄効果がさらに加えられるため、本発明に係る超純水製造システムの洗浄方法による洗浄効果をより優れたものとすることができる。以下、上記アルカリ等を用いて高圧洗浄工程を行った際の洗浄効果等について、説明する。 The cleaning method of the ultrapure water production system according to the present invention is not limited to the above embodiment, and the ultrapure water in the high pressure cleaning step includes alkali, hydrogen peroxide (H 2 O 2 ), ozone or gas, or Hot water may be used. In this way, by performing cleaning by combining ultrapure water and alkali or the like, chemical cleaning effect by alkali or the like and physical cleaning effect by gas are further added to the physical cleaning effect of the high pressure cleaning process by ultrapure water. Therefore, the cleaning effect by the cleaning method of the ultrapure water production system according to the present invention can be further improved. Hereinafter, the cleaning effect when the high pressure cleaning process is performed using the alkali or the like will be described.
　［アルカリ］
　アルカリを用いることにより、サブシステム４の配管等に付着している微粒子を化学的に剥離、分散することができる。アルカリを含む超純水としては、テトラメチルアンモニウムヒドロキシド水溶液又はコリン、苛性ソーダ、アンモニアのいずれかを含む溶液が好ましく、ｐＨ１０以上であることが好ましい。また、アルカリを含む超純水による洗浄時間は、０．５～２時間の範囲であることが好ましい。 [alkali]
By using alkali, fine particles adhering to the piping of the subsystem 4 can be chemically peeled and dispersed. The ultrapure water containing alkali is preferably a tetramethylammonium hydroxide aqueous solution or a solution containing any of choline, caustic soda and ammonia, and preferably has a pH of 10 or more. Further, the washing time with ultrapure water containing alkali is preferably in the range of 0.5 to 2 hours.
　［過酸化水素］
　過酸化水素（Ｈ２Ｏ２）を用いることにより、過酸化水素（Ｈ２Ｏ２）の発泡力によって、サブシステム４の配管等に付着している微生物を化学的に除去することができる。過酸化水素（Ｈ２Ｏ２）を含む超純水の濃度は０．１％以上であることが好ましい。また、過酸化水素（Ｈ２Ｏ２）を含む超純水による洗浄時間は、０．５～２時間の範囲であることが好ましい。 [hydrogen peroxide]
The use of hydrogen peroxide (H 2 O 2), the foaming power of hydrogen peroxide (H 2 O 2), it is possible to chemically remove the microorganisms adhering to the piping of the subsystem 4. The concentration of ultrapure water containing hydrogen peroxide (H 2 O 2 ) is preferably 0.1% or more. The cleaning time with ultrapure water containing hydrogen peroxide (H 2 O 2 ) is preferably in the range of 0.5 to 2 hours.
　［オゾン］
　オゾンを用いることにより、オゾンの酸化分解力により、サブシステム４の配管等に付着している微粒子を化学的に除去することができる。オゾンを含む超純水の濃度は０．１ｍｇ／Ｌ以上であることが好ましい。また、オゾンを含む超純水による洗浄時間は、０．５～２時間の範囲であることが好ましい。 [ozone]
By using ozone, the fine particles adhering to the piping of the subsystem 4 can be chemically removed by the oxidative decomposition power of ozone. The concentration of ultrapure water containing ozone is preferably 0.1 mg / L or more. The cleaning time with ultrapure water containing ozone is preferably in the range of 0.5 to 2 hours.
　［気体］
　空気や窒素等の気体を連続的又は間欠的に超純水に導入することにより、空気や窒素等の気泡によって、洗浄水が強く撹拌されるので、サブシステム４の配管等に付着している微粒子を物理的に剥離、分散することができる。 [gas]
By introducing a gas such as air or nitrogen continuously or intermittently into the ultrapure water, the washing water is strongly stirred by bubbles such as air or nitrogen, so that it adheres to the piping of the subsystem 4 or the like. Fine particles can be physically peeled and dispersed.
　［熱水］
　高圧洗浄工程における超純水が熱水であることにより、サブシステム４の配管等を殺菌洗浄することができる。熱水の温度は６０℃以上であることが好ましい。熱水による殺菌洗浄を行う場合は、サブシステム４の配管は、耐熱性に優れたＰＶＤＦ製であることが好ましい。 [hot water]
Since the ultrapure water in the high-pressure washing process is hot water, the piping of the subsystem 4 can be sterilized and washed. The temperature of hot water is preferably 60 ° C. or higher. When performing sterilization washing with hot water, the piping of the subsystem 4 is preferably made of PVDF having excellent heat resistance.
　＜排出工程＞
　また、本実施形態において、本発明に係る超純水製造システムの洗浄方法は上記高圧洗浄工程後に系内に滞留している超純水を系外に押し出す排出工程を有する。排出工程の通水時間は、０．５～２４時間の範囲であることが好ましい。 <Discharge process>
Moreover, in this embodiment, the washing | cleaning method of the ultrapure water manufacturing system which concerns on this invention has the discharge process which pushes out the ultrapure water which retains in a system after the said high pressure washing process out of the system. The water passing time in the discharging step is preferably in the range of 0.5 to 24 hours.
　本実施形態に係る超純水製造システムの洗浄方法おける上記高圧洗浄工程、上記アルカリ等及び上記排出工程との組み合わせとしては、アルカリを含む超純水による高圧洗浄工程、過酸化水素（Ｈ２Ｏ２）を含む超純水による洗浄、排出工程をこの順に行うのが好ましい。このように組み合わせることで、アルカリ及び過酸化水素（Ｈ２Ｏ２）による化学的洗浄と超純水の高圧供給による物理的洗浄の双方の効果が期待できる。上記組み合わせにおいて、アルカリを含む超純水による高圧洗浄工程、過酸化水素（Ｈ２Ｏ２）を含む超純水による洗浄は、この順に２回繰り返されてもよい。アルカリ及び過酸化水素（Ｈ２Ｏ２）による洗浄を２回繰り返すことにより、化学的洗浄の効果が更に高まる。 The combination of the high-pressure cleaning step, the alkali and the like and the discharge step in the cleaning method of the ultrapure water production system according to the present embodiment includes a high-pressure cleaning step using ultrapure water containing alkali, hydrogen peroxide (H 2 O It is preferable to perform the washing and discharging steps with ultrapure water containing 2 ) in this order. By combining in this way, the effects of both chemical cleaning with alkali and hydrogen peroxide (H 2 O 2 ) and physical cleaning with high-pressure supply of ultrapure water can be expected. In the above combination, the high-pressure cleaning step using ultrapure water containing alkali and the cleaning using ultrapure water containing hydrogen peroxide (H 2 O 2 ) may be repeated twice in this order. By repeating the cleaning with alkali and hydrogen peroxide (H 2 O 2 ) twice, the effect of chemical cleaning is further enhanced.
　上記組み合わせにおいて、アルカリを含む超純水による高圧洗浄工程を、アルカリを含む超純水による洗浄と、超純水による高圧洗浄工程とに分けて行ってもよい。この場合、超純水による高圧洗浄工程は、アルカリ洗浄後に行うのが好ましい。ここで、アルカリ洗浄後とは、アルカリによる洗浄における所定時間の経過後、所定流量の通水後又は微粒子計測数が定常状態になったことを確認した後を指す。 In the above combination, the high-pressure cleaning step using ultrapure water containing alkali may be performed separately in the cleaning using ultrapure water containing alkali and the high-pressure cleaning step using ultrapure water. In this case, it is preferable to perform the high-pressure washing process with ultrapure water after alkali washing. Here, “after alkali cleaning” refers to after the passage of a predetermined time in cleaning with alkali, after passing water at a predetermined flow rate, or after confirming that the number of fine particle measurement is in a steady state.
　また、上記組み合わせにおいては、高圧洗浄工程をさらに、排出工程中に行ってもよいし、排出工程後に行ってもよい。ここで、排出工程後とは、排出工程における所定時間の経過後、所定流量の通水後又は微粒子計測数が定常状態になったことを確認した後を指す。排出工程中に又は排出工程後に高圧洗浄工程を実施することで、排出工程だけでは押し出しきれない又は押し出しきれなかった処理水が系外に押し出されるため、処理水に分散している微粒子が配管の内壁等に再付着することを防ぐという効果が期待できる。 In the above combination, the high-pressure washing process may be further performed during the discharging process or after the discharging process. Here, “after the discharge process” refers to after the passage of a predetermined time in the discharge process, after passing water at a predetermined flow rate, or after confirming that the number of fine particle measurement has reached a steady state. By carrying out the high-pressure washing process during or after the discharge process, the treated water that could not be pushed out or could not be pushed out by the discharge process alone was pushed out of the system. The effect of preventing reattachment to the inner wall can be expected.
　上述のような組み合わせによる洗浄に要する時間は、２時間～７日である。洗浄を終了するタイミングは、返送配管Ｒ１に設置されるオンライン微粒子モニター（図示しない）で計測することにより、処理水に存在する２０ｎｍ以上の微粒子数が１個／ｍＬ以下（定常状態）になっているかどうかで判断される。 The time required for cleaning by the combination as described above is 2 to 7 days. The timing for ending the cleaning is measured by an on-line particle monitor (not shown) installed in the return pipe R1, so that the number of particles of 20 nm or more present in the treated water is 1 / mL or less (steady state). It is judged by whether or not.
　なお、超純水製造システムの洗浄時には、限外ろ過膜装置（ＵＦ装置）４７に代えて、ポリ塩化ビニル（ＰＶＣ）製のダミー管（図示しない）又はＵＦ機能を有しないダミーＵＦ装置（図示しない）が設置される。ダミー管又はダミーＵＦ装置を用いることにより、洗浄段階でＵＦ装置が目詰まりしてしまうことを防ぐことができるので、ＵＦ装置にかかるコストを削減することができる。なお、ダミー管又はダミーＵＦ装置を使用する場合、洗浄に要する時間は、１２時間～７日である。 When cleaning the ultrapure water production system, instead of the ultrafiltration membrane device (UF device) 47, a polyvinyl chloride (PVC) dummy tube (not shown) or a dummy UF device having no UF function (not shown) Not) is installed. By using the dummy tube or the dummy UF device, it is possible to prevent the UF device from being clogged at the cleaning stage, so that the cost of the UF device can be reduced. When a dummy tube or a dummy UF device is used, the time required for cleaning is 12 hours to 7 days.
　以上、本発明について図面を参照にして説明してきたが、本発明は上記実施形態に限定されず、種々の変更実施が可能である。 As mentioned above, although this invention has been demonstrated with reference to drawings, this invention is not limited to the said embodiment, A various change implementation is possible.
　以下、実施例に基づき本発明をさらに詳細に説明するが、本発明は以下の実施例に限定されるものではない。 Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to the following examples.
　［実施例１］
　図１に示す超純水製造システムを用いてサブシステム４の洗浄を行った。返送配管Ｒ２に、オンライン微粒子モニタ（Ｐａｒｔｉｃｌｅ　Ｍｅａｓｕｒｉｎｇ　Ｓｙｓｔｅｍｓ社製，商品名：ＵＤＩ－２０）を設置し、返送配管Ｒ１の配管圧力を０．４ＭＰａから０．７ＭＰａへ変更した。 [Example 1]
Subsystem 4 was cleaned using the ultrapure water production system shown in FIG. An on-line particulate monitor (manufactured by Particle Measuring Systems, product name: UDI-20) was installed in the return pipe R2, and the pipe pressure of the return pipe R1 was changed from 0.4 MPa to 0.7 MPa.
　［結果］
　圧力及び微粒子数と洗浄後経過時間の関係を図２に示す。本結果からわかるように、圧力が高くなると、微粒子が発塵する。これにより、サブシステム４の配管洗浄を高圧条件で行うことに一定の効果があることがわかる。 [result]
FIG. 2 shows the relationship between the pressure and the number of fine particles and the elapsed time after cleaning. As can be seen from this result, when the pressure increases, fine particles are generated. Thus, it can be seen that there is a certain effect in performing the pipe cleaning of the subsystem 4 under a high pressure condition.
　［実施例２，比較例］
　返送配管Ｒ２として、配管径２５ＡのＰＶＤＦ製配管を用い、配管長５０ｍで２本設置した。１本はアルカリを含む超純水を用いて連続的高圧洗浄を行い、比較例として、もう１本はアルカリを含む超純水による洗浄のみを行った。通水速度はいずれも０．５ｍ／ｓｅｃとし、流量は３ｍ３とした。返送配管Ｒ２の圧力は、アルカリ洗浄＋連続的高圧洗浄（実施例２）については０．４ＭＰａ、アルカリ洗浄のみ（比較例）については０．３ＭＰａとした。通常時の圧力は０．３ＭＰａとした。返送配管Ｒ２に設置したオンライン微粒子モニタ（ＵＤＩ－２０：Ｐａｒｔｉｃｌｅ　Ｍｅａｓｕｒｉｎｇ　Ｓｙｓｔｅｍｓ社製）を用いて微粒子数を計測した。 [Example 2, comparative example]
Two PVDF pipes with a pipe diameter of 25A were used as the return pipe R2, and two pipes were installed with a pipe length of 50 m. One was subjected to continuous high-pressure washing using ultrapure water containing alkali, and as another comparative example, the other was washed only with ultrapure water containing alkali. In each case, the water flow rate was 0.5 m / sec, and the flow rate was 3 m 3 . The pressure of the return pipe R2 was 0.4 MPa for alkali cleaning + continuous high pressure cleaning (Example 2), and 0.3 MPa for only alkali cleaning (Comparative Example). The normal pressure was 0.3 MPa. The number of fine particles was measured using an online fine particle monitor (UDI-20: manufactured by Particle Measuring Systems) installed in the return pipe R2.
　［結果］
　アルカリを含む超純水を用いて連続的高圧洗浄を行った場合（実施例２）の微粒子数と洗浄後経過時間の関係を図３に、アルカリを含む超純水による洗浄のみを行った場合（比較例）の微粒子数と洗浄後経過時間の関係を図４に示す。本結果からわかるように、アルカリを含む超純水を用いて連続的高圧洗浄を行うと、２０ｎｍ以上の微粒子数が３０時間経過後から安定する。これにより、連続的高圧洗浄にアルカリ洗浄を組み合わせると、洗浄時間が短縮されることがわかる。 [result]
FIG. 3 shows the relationship between the number of fine particles and the elapsed time after cleaning when performing continuous high-pressure cleaning using ultrapure water containing alkali (Example 2), and cleaning only with ultrapure water containing alkali. The relationship between the number of fine particles and the elapsed time after cleaning is shown in FIG. As can be seen from this result, when continuous high-pressure cleaning is performed using ultrapure water containing alkali, the number of fine particles of 20 nm or more is stabilized after 30 hours. This shows that the cleaning time is shortened when alkaline cleaning is combined with continuous high-pressure cleaning.
　以上説明したように、本発明の超純水製造システムの洗浄方法によれば、超純水を高圧供給することによって、超純水製造システム内、特に配管の内壁等に付着している微粒子を効率的に剥離、除去することができるので、洗浄作業を短時間で行うことができる。また、アルカリを含む超純水によって高圧洗浄工程を行った場合には、超純水を高圧供給することによる物理的洗浄効果にアルカリによる化学的洗浄効果が加えられるため、より効果的に超純水製造システム内洗浄を行うことができる。 As described above, according to the cleaning method of the ultrapure water production system of the present invention, by supplying ultrapure water at a high pressure, fine particles adhering to the inside of the ultrapure water production system, in particular, the inner wall of the pipe are removed. Since it can peel and remove efficiently, a cleaning operation can be performed in a short time. In addition, when the high-pressure cleaning process is performed with ultrapure water containing alkali, the chemical cleaning effect due to alkali is added to the physical cleaning effect of supplying ultrapure water at a high pressure, so that ultrapure water is more effective. Cleaning in the water production system can be performed.
　本発明は、超純水製造システムを新規に立ち上げた場合や、一定期間稼働を休止した後に再立ち上げした場合に、システム内に混入又は発生した不純物を除去してユースポイントにおける超純水が要求水質を満たすようになるまでシステムを洗浄するための方法として有用である。 The present invention eliminates impurities mixed or generated in the system when the ultrapure water production system is newly started up or when it is restarted after a certain period of operation stoppage. It is useful as a method for cleaning the system until it meets the required water quality.
１…超純水製造システム
２…前処理システム
３…一次純水システム
４…超純水製造装置（サブシステム）
　４１…サブタンク
　４２…熱交換器
　４３…紫外線酸化装置（ＵＶ装置）
　４４…触媒式酸化性物質分解装置
　４５…脱気装置
　４６…混床式イオン交換装置
　４７…限外ろ過膜装置（ＵＦ装置）
５…ユースポイント
Ｌ１，Ｌ２，Ｌ３１～３６，Ｌ４…送水配管
Ｒ１，Ｒ２…返送配管
Ｐ…ポンプ
Ｗ…原水 DESCRIPTION OF SYMBOLS 1 ... Ultrapure water production system 2 ... Pretreatment system 3 ... Primary pure water system 4 ... Ultrapure water production apparatus (subsystem)
41 ... Sub tank 42 ... Heat exchanger 43 ... UV oxidation device (UV device)
44 ... Catalytic oxidizing substance decomposition device 45 ... Deaeration device 46 ... Mixed bed type ion exchange device 47 ... Ultrafiltration membrane device (UF device)
5 ... Use points L1, L2, L31 to 36, L4 ... Water supply piping R1, R2 ... Return piping P ... Pump W ... Raw water

Claims (6)

  1. 　超純水製造装置、ユースポイント及び前記超純水製造装置と前記ユースポイントとを接続する配管を備える超純水製造システムの少なくとも一部を洗浄する方法であって、
    　超純水を高圧で供給することにより洗浄する高圧洗浄工程を有する超純水製造システムの洗浄方法。     A method for cleaning at least a part of an ultrapure water production system, a use point, and an ultrapure water production system comprising a pipe connecting the ultrapure water production device and the use point,
    A cleaning method for an ultrapure water production system having a high pressure cleaning process for cleaning by supplying ultrapure water at a high pressure.
  2. 　前記高圧洗浄工程における超純水の供給を、前記ユースポイントにおける着圧よりも高い圧力で連続的もしくは間欠的に行う、又は前記ユースポイントにおける着圧よりも高い圧力まで漸次的に上昇させて行う請求項１に記載の超純水製造システムの洗浄方法。 Supplying ultrapure water in the high-pressure washing step is performed continuously or intermittently at a pressure higher than the arrival pressure at the use point, or gradually increased to a pressure higher than the arrival pressure at the use point. The cleaning method of the ultrapure water production system according to claim 1.
  3. 　前記配管の少なくとも一部がポリフッ化ビニリデン（ＰＶＤＦ）からなる請求項１又は請求項２に記載の超純水製造システムの洗浄方法。 The method for cleaning an ultrapure water production system according to claim 1 or 2, wherein at least a part of the piping is made of polyvinylidene fluoride (PVDF).
  4. 　前記高圧洗浄工程における超純水が、アルカリ、過酸化水素（Ｈ２Ｏ２）、オゾンもしくは気体を含む、又は熱水である請求項１から請求項３のいずれか１項に記載の超純水製造システムの洗浄方法。 The ultrapure water according to any one of claims 1 to 3, wherein the ultrapure water in the high-pressure washing step contains alkali, hydrogen peroxide (H 2 O 2 ), ozone or gas, or is hot water. Cleaning method for water production system.
  5. 　前記高圧洗浄工程後に系内に滞留している超純水を系外に押し出す排出工程を有する請求項１から請求項４のいずれか１項に記載の超純水製造システムの洗浄方法。 The method for cleaning an ultrapure water production system according to any one of claims 1 to 4, further comprising a discharge step of pushing out ultrapure water remaining in the system after the high-pressure cleaning step.
  6. 　前記超純水製造装置が限外ろ過膜装置（ＵＦ装置）を備え、
    　前記超純水製造システムの洗浄時には、前記限外ろ過膜装置（ＵＦ装置）に代えて、ダミー管又はＵＦ機能を有しないダミーＵＦ装置を設置して通水する請求項１から請求項５のいずれか１項に記載の超純水製造システムの洗浄方法。     The ultrapure water production apparatus comprises an ultrafiltration membrane device (UF device),
    6. In cleaning the ultrapure water production system, instead of the ultrafiltration membrane device (UF device), a dummy tube or a dummy UF device having no UF function is installed and water is passed. The method for cleaning an ultrapure water production system according to any one of the above.
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