JP2017200683A - Start-up method of ultra-pure water manufacturing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a start-up method of an ultra-pure water manufacturing apparatus capable of suppressing a hunting phenomenon of the number of particulates after the ultra-pure water manufacturing is started, and stably providing ultra-pure water with an extremely low particulate concentration.SOLUTION: There is provided a start-up method of an ultra-pure water manufacturing apparatus that cleans the inside of an ultra-pure water manufacturing apparatus system prior to supplying the ultra-pure water to a use place in the ultra-pure water manufacturing apparatus for processing primary pure water to manufacture ultra-pure water and supplying it to the use place. Pure water containing hydrogen peroxide or gaseous matter is caused to stagnate or flow in a flow channel of the ultra-pure water manufacturing apparatus, and vibration is applied to at least part of the flow channel from the outside so as to remove particulates adhering to the inner surface of the flow channel.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for starting up an ultrapure water production apparatus.

  Conventionally, in the manufacturing process of electronic parts such as semiconductor devices, liquid crystal displays, silicon wafers, printed boards, etc., ultrapure water with extremely low content of impurities such as ionic substances, fine particles, organic substances, dissolved gases and viable bacteria has been used. ing. In recent years, as the degree of integration of semiconductor devices has improved, the demand for the purity of ultrapure water has become increasingly severe. For example, the specifications of the state-of-the-art ultrapure water for semiconductor manufacturing are: resistivity 18.2 MΩ · cm or more, number of fine particles of 0.05 μm or more is 1 / mL or less, and total organic carbon (TOC) concentration is 1 μgC / L or less And the required water quality tends to become more severe.

  Such ultrapure water is generally an ultrapure water production system composed of a pretreatment device, a primary pure water system, and a secondary pure water system (subsystem), such as industrial water, city water, and well water. It is manufactured by processing raw water. The manufactured ultrapure water is supplied to a use point as a place of use.

  The pretreatment device is to obtain pretreatment water by turbidizing raw water using a coagulating sedimentation device, a sand filtration device or the like. For the primary pure water system, an activated carbon device, a reverse osmosis membrane device, a two-bed / three-column ion exchange resin device, a vacuum deaeration device, an ultraviolet oxidation device, a mixed bed ion exchange resin device, a precision filter, etc. are appropriately selected and used. The primary pure water is obtained by removing impurities in the pretreatment water. The secondary pure water system (subsystem) temporarily stores primary pure water (primary) on the downstream side of the pure water tank, for example, a heat exchanger, an ultraviolet oxidizer, a non-regenerative mixed bed type ion exchange It comprises a resin device (Polisher), a degassing membrane device, an ultrafiltration device and the like.

  When starting up after a new installation of ultrapure water production equipment or at the time of restarting after an outage due to periodic inspections, etc., the impurities described above that are mixed or generated in the system are removed to remove ultrapure water at the point of use. A start-up operation is performed to clean the ultrapure water production apparatus until the desired water quality is achieved. For this reason, a startup period is required from the start of the ultrapure water production system until the ultrapure water of the desired water quality can be used at the point of use, but in recent years, for the purpose of improving the operating efficiency of the factory, There is a strong demand for shortening the startup period.

  Cleaning methods during the startup operation of the ultrapure water production system include flushing and blowing with ultrapure water, circulation of ultrapure water, warm water cleaning, hydrogen peroxide cleaning, and alkaline cleaning (basic aqueous solution cleaning). It was broken. In addition, ultrapure water (functional water) in which functional gases such as ozone and hydrogen are dissolved, and a cleaning method using a surfactant have been proposed.

  For example, Patent Document 1 discloses a method of removing fine particles by changing the surface potential of fine particles adhering to a contact surface with ultra pure water in an ultra pure water production apparatus. Patent Document 2 includes a step of performing circulation cleaning with a basic cleaning solution, a step of performing extrusion and rinsing of the basic cleaning solution with pure water, a step of performing circulation and / or immersion cleaning with a hydrogen peroxide cleaning solution, and A method of cleaning an ultrapure water production and supply apparatus that sequentially performs a process of pushing and rinsing a hydrogen peroxide cleaning solution with pure water is disclosed.

JP 2002-52322 A JP 2006-297180 A

  However, in the conventional cleaning method described above, the number of fine particles of 0.05 μm or more is approximately 1 pc. / ML (1000 pcs./L) or less, but 1 pcs. / ML or less, the hunting phenomenon that the number of fine particles rises intermittently for a predetermined time has occurred, and it has been found that the number of fine particles in ultrapure water produced after start-up operation has not been stably reduced. It was. That is, when the number of fine particles was continuously measured after the start-up operation by the conventional cleaning method or the like, it was found that the hunting phenomenon in which the number of fine particles temporarily rises appears about once every several hours to several days. In this case, in order to eliminate the hunting phenomenon, pure water is passed through the ultrapure water production system, but it is understood that the disappearance of the hunting phenomenon takes about one month to several months. It was.

  Further, in recent years, the quality of ultrapure water is 1 pcs. / ML or less has been required. In order to obtain the above-mentioned water quality, several months to half a year at the earliest until the hunting phenomenon after the start-up operation of the ultrapure water production apparatus by the conventional cleaning method is completely eliminated, and in some cases half a year to one year. It has become clear that it takes about a long time. Therefore, a startup method that can further shorten the startup period has become necessary.

  The present invention has been made to solve the above-described problems, and it is possible to suppress the hunting phenomenon of the number of fine particles after the start of production of ultra pure water and to stably obtain ultra pure water having a very low concentration of fine particles. It aims at providing the starting method of a pure water manufacturing apparatus.

  The method for starting up the ultrapure water production apparatus of the present invention is to supply the ultrapure water to the place of use in the ultrapure water production apparatus that processes primary pure water to produce ultrapure water and supplies it to the place of use. Prior to the above, a method for starting up an ultrapure water production apparatus for cleaning the inside of the ultrapure water production apparatus system, wherein pure water containing hydrogen peroxide or gas is added to a flow path of the ultrapure water production apparatus. It is characterized in that the particles are retained or flowed, and at least a part of the flow path is vibrated from the outside to remove fine particles adhering to the inner surface of the flow path.

  In the start-up method of the ultrapure water production apparatus of the present invention, the vibration is preferably 600 gal or more.

  In the start-up method of the ultrapure water production apparatus of the present invention, the gas is preferably at least one selected from nitrogen, carbon dioxide and hydrogen. Further, the water pressure of the pure water flowing through the flow path is not less than the water pressure when producing the ultrapure water in the ultrapure water production apparatus and not more than twice the water pressure when producing the ultrapure water. Is preferred.

  In the start-up method of the ultrapure water production apparatus of the present invention, it is preferable that the temperature of the pure water containing hydrogen peroxide or gas passed through the flow path is 10 ° C to 45 ° C.

  In the start-up method of the ultrapure water production apparatus according to the present invention, it is preferable that the ultrapure water production apparatus includes a fine particle removing unit and applies the vibration to the flow path of the fine particle removing unit.

  In the start-up method of the ultrapure water production apparatus of the present invention, it is preferable that the vibration is applied to at least one selected from a joint, a valve, a curved pipe part, and a branch part constituting the flow path of the ultrapure water production apparatus. .

  In the start-up method of the ultrapure water production apparatus of the present invention, it is preferable that oxygen or the gas generated from the hydrogen peroxide is dissolved in the primary pure water with supersaturation.

  In the start-up method of the ultrapure water production apparatus of the present invention, it is preferable that bubbles are contained in the pure water containing hydrogen peroxide or gas.

  In the start-up method of the ultrapure water production apparatus of the present invention, after removing the fine particles, the pure water containing hydrogen peroxide or gas is passed through the flow path by passing pure water through the ultrapure water production apparatus. It is preferable to discharge out of the system.

  According to the start-up method of the ultrapure water production apparatus of the present invention, the hunting phenomenon of the number of fine particles after the start of production of ultrapure water can be suppressed, and ultrapure water having a very low concentration of fine particles can be obtained stably.

It is a block diagram which represents roughly an example of the ultrapure water manufacturing apparatus which is the starting cleaning object of this invention. FIG. 2 is a block diagram schematically showing an ultrapure water production system including the ultrapure water production apparatus 1 shown in FIG. 1 as a secondary pure water system. In an Example, it is a graph which shows the relationship between elapsed time and the number of microparticles | fine-particles when washing | cleaning is fully performed. In a comparative example, it is a graph which shows the relationship between elapsed time and the number of microparticles | fine-particles in case cleaning is not fully performed.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
(First embodiment)
As shown in FIG. 1, an ultrapure water production apparatus 1 that is an object to be started up and washed according to the present invention has a unit for water treatment downstream of a primary pure water tank (TK) 10 that temporarily stores primary pure water. As equipment, heat exchanger (HEX) 11 for water temperature control, ultraviolet oxidation device (TOC-UV) 12 for decomposing organic matter, membrane degassing device (MDG) 13, non-regenerative mixed bed ion exchange resin device (Polisher) 14, comprising an ultrafiltration device 15 as a fine particle removing means for removing fine particles. The ultrapure water production apparatus 1 is connected to a use point (POU) 16 as a place where ultrapure water is used, and supplies the produced ultrapure water to the use point 16. Further, the ultrapure water production apparatus 1 includes a circulation pipe 19 that circulates ultrapure water that is not used at the use point 16 to the single pure water tank 10.

  In addition, the ultrapure water production apparatus 1 is connected to the water treatment unit pipes 17 and the treated water pipes 17 for connecting the water treatment unit units, and the treated water pipes 17. A pump P1 for sending the primary pure water downstream, and a valve V1 that is inserted downstream of the pump P1 in the treated water piping 17 and switches between supply and stop of the primary pure water to the ultrapure water production apparatus 1. It has. A particulate meter 25 for measuring the number of fine particles in the water is connected to the treated water pipe 17 after the ultrafiltration device 15. Further, a drain pipe 18 for discharging water to the outside of the system is connected to the circulation pipe 19 via a three-way valve V2.

  Although the flow path in the ultrapure water production apparatus 1 is composed of pipes and tubes, in this embodiment, including those in which tanks, pumps, joints, valves, and other equipment are appropriately arranged in the middle of the flow path. This is referred to as a flow path. As a material constituting the flow path of such water to be treated, any material can be used as long as the components are not easily eluted into ultrapure water. For example, polyvinyl chloride (PVC), polyphenylene sulfide (PPS), polyfluoride Vinylidene (PVDF), fiber reinforced plastic (FRP), tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer (PFA), stainless steel, or the like can be used.

  Prior to the production of the ultrapure water, the method for starting up the ultrapure water production apparatus according to the present embodiment is as follows in order to remove fine particles adhering to the inner surface of the flow path of the ultrapure water production apparatus 1. In addition, it is performed through a washing step, a de-drug step, and a flushing step.

  First, the three-way valve V2 is switched from the drain pipe 18 side to the primary pure water tank 10 side, the valve V1 is opened, and the pump P1 is operated. Thereby, the primary pure water (pure water) stored in the primary pure water tank 10 is caused to flow into the ultrapure water production apparatus 1 and further circulated through the circulation pipe 19.

  Then, hydrogen peroxide or gas is dissolved in the primary pure water that is passed through the ultrapure water production apparatus 1. In addition, in the state where the primary pure water in which the hydrogen peroxide or gas is dissolved (hereinafter also referred to as “gas dissolved water”) is retained or circulated, at least a part of the flow path of the ultrapure water production apparatus 1 is provided. Apply vibration from outside (cleaning process).

  By applying the above vibration to the flow path of the ultrapure water production apparatus 1, vibration energy is given to the fine particles adhering to the inner surface of the flow path, thereby separating the fine particles from the inner surface of the flow path, It can be dispersed and removed. Further, the gas in the gas-dissolved water becomes bubbles, and the separation of fine particles from the inner surface of the flow path can be promoted.

  Moreover, the gas in primary pure water has an effect of improving the effect of removing fine particles by vibration. That is, as a result of various studies by the present inventors, if the gas in the primary pure water is in a supersaturated state or near supersaturated state, it is thought that the effect of removing fine particles is improved by adding vibration in that state. I understood that. Hydrogen peroxide decomposes in water to become oxygen, which is thought to create a similar situation.

  Examples of the gas dissolved in the primary pure water include nitrogen, hydrogen, and carbon dioxide. Of these, nitrogen is preferable.

  A method for dissolving hydrogen peroxide or gas in primary pure water is not particularly limited. For example, as a method for dissolving the gas, there is a method in which the membrane degassing device 13 is used as a gas dissolving device, and the gas is dissolved using the degassing membrane as a dissolving film. Further, since the upper part of the primary pure water tank 10 is usually hermetically sealed and purged with nitrogen, nitrogen is dissolved in the primary pure water in the primary pure water tank 10. If primary pure water is supplied from the primary pure water tank 10 with the membrane deaerator 13 stopped, nitrogen-dissolved water can be supplied.

  As a method for dissolving hydrogen oxide or gas, hydrogen peroxide or gas is dissolved in primary pure water supplied to the ultrapure water production apparatus 1 or primary pure water circulating in the ultrapure water production apparatus 1 system. The method may be used. In this case, for example, a method of injecting pure water in which hydrogen peroxide or gas is dissolved into the treated water pipe 17 immediately before the unit device or the group of unit devices to be cleaned by a chemical pump or the like may be adopted. it can. Alternatively, primary pure water in which hydrogen peroxide or gas is dissolved in advance may be supplied to the ultrapure water production apparatus 1 and circulated in the system.

  The concentration of hydrogen peroxide or gas is not particularly limited as long as it is an amount capable of generating bubbles, but a state in which 1 to 3 times the gas is dissolved with respect to the solubility of hydrogen peroxide or gas at the temperature. If it becomes. The concentration of hydrogen peroxide or gas is preferably 24 mg / L to 60 mg / L in the case of nitrogen with respect to the primary pure water to be passed. In the case of hydrogen, it is preferably 1.2 mg / L to 3 mg / L. In the case of hydrogen peroxide, it is preferably added at a concentration of 1% by mass to 5% by mass. As a result, oxygen generated by the decomposition of hydrogen peroxide is in a dissolved state of 8 mg / L to 25 mg / L. The bubble is a bubble of several microns to several hundred microns, and can be generated by applying vibration to primary pure water in which the oxygen or gas is dissolved with supersaturation.

  Although the pressure at the time of supply of the gas dissolved water by the pump P1 is not particularly limited, the pressure of primary pure water supplied to the ultrapure water production apparatus 1 at the time of ultrapure water production is twice or less from 30 to 40% smaller pressure. It is preferable that the pressure be approximately equal to Moreover, the pressure at the time of supply of gas dissolution water is twice the pressure in the permeation | transmission side of the ultrafiltration apparatus 15 in the circulation piping 19 from the pressure 30-40% smaller than the pressure of the same location at the time of ultrapure water manufacture. The pressure is preferably about the following pressure. If the supply pressure of the gas dissolved water is too small, the concentration of the dissolved water is not sufficient, and the effect of promoting separation of the fine particles from the flow path may be reduced. On the other hand, if it is too large, the amount of bubbles is too large when vibration is applied, so that huge bubbles are generated and the effect of promoting the peeling of fine particles may be reduced. Specifically, the supply pressure of the gas dissolved water by the pump P1 during the start-up operation is, for example, 0.2 MPa to 0.5 MPa.

  Moreover, in order to make the gas in the gas-dissolved water supersaturated or close to supersaturation, it is preferable to raise the temperature of the gas-dissolved water circulated in the ultrapure water production apparatus 1. When the water in the circulation system is cooled by the heat exchanger, the water temperature can be raised by stopping this. Further, the water temperature may be raised by supplying a heat source to the heat exchanger.

  The temperature of the gas dissolved water to be passed is preferably 10 ° C to 45 ° C, more preferably 10 ° C to 40 ° C, and further preferably 25 ° C to 40 ° C. Thereby, since the solubility of gas is reduced, generation | occurrence | production of the bubble from the said gas can be accelerated | stimulated and the peeling promotion effect of the microparticles | fine-particles from a flow path can be improved.

  Moreover, in order to make the gas in the gas dissolved water supersaturated or close to supersaturated, it was installed in the valve V1, the three-way valve V2 or the ultrapure water circulation system when giving the vibration or immediately before giving the vibration. It is preferable to reduce the pressure in the circulatory system by adjusting the opening of other valves or adjusting the output of the pump.

  The flow time of the gas-dissolved water may be, for example, 5 minutes to 60 minutes, although it depends on the length and the inner diameter of the flow path constituting the ultrapure water production apparatus 1. Moreover, it does not specifically limit about the flow rate of gas dissolution water, For example, Preferably it is 0.001 m / s-3.0 m / s, More preferably, it may be 0.5 m / s-2.0 m / s.

  In this way, when the hydrogen peroxide or gas reaches a supersaturated state at a predetermined concentration, the supply of hydrogen peroxide or nitrogen is stopped. Then, in a state where the gas-dissolved water is circulated in the ultrapure water production apparatus 1 system, vibration is applied from the outside to at least a part of the flow path of the ultrapure water production apparatus 1.

  When applying vibration, the discharge pressure of the pump P1 is operated at a pressure equal to or lower than the pressure at the time of supplying the gas dissolved water, for example, preferably 25 to 75% of the pressure at the time of supplying the gas dissolved water. May be circulated in the ultrapure water production apparatus 1 system. This is because if the supply pressure of the dissolved gas at the time of applying vibration is too high, bubbles are not sufficiently generated, and the effect of promoting the separation of the fine particles from the flow path may be reduced. Moreover, when giving a vibration, you may make gas dissolved water retain in the flow path of the ultrapure water manufacturing apparatus 1, and what is necessary is just to stop the pump P1 in this case.

  The vibration applied to the flow path is preferably 600 Gal or more, and more preferably 700 Gal or more. Moreover, it is preferable that the vibration given to a flow path is 100,000 Gal or less. This is because the greater the vibration applied to the flow path, the greater the effect of separating the fine particles from the inner surface of the flow path, but if the vibration is too large, the piping may be deteriorated or broken.

  The time for applying the vibration is approximately 1 to 5 minutes although it depends on the place where the vibration is applied and the magnitude of the vibration.

  The method of applying vibration is not particularly limited, and examples thereof include a method of hitting the flow path with a bare hand or a tool such as a wooden hammer or a hammer, a method of applying ultrasonic vibration, and the like. Here, for example, the vibration applied to the flow path when struck with a bare hand is 800 Gal or more, 1400 Gal or more for a wooden mallet, and 5000 Gal or more for an ultrasonic wave. The vibration given to the flow path can be measured by, for example, a vibration analyzer.

  Although it does not specifically limit as a place which gives a vibration, For example, the above-mentioned of the flow path through which to-be-processed water flows in the treated water piping 17, the circulation piping 16, and each unit apparatus from the entrance side of the pump P1 to the use point 16. A connecting portion such as a valve or a joint, a bent pipe portion or a branch portion is preferable. Fine particles are likely to stay and adhere to the connection portion and the inner surface of the flow path of the bent tube portion or the branch portion. According to the start-up method of the present embodiment, excellent peeling and removal effects can be obtained even for such fine particles.

  Further, the place where vibration is applied is preferably a particulate removing means provided in the ultrapure water production apparatus 1, for example, a flow path of the ultrafiltration device 15. In addition to the ultrafiltration device 15, a microfilter (MF) or a nanofilter (NF) may be provided as the particulate removing means. In this case, these microfilter (MF) or nanofilter ( NF) may be vibrated. The fine particles flowing from the upstream side of the ultrapure water production apparatus 1 may stay and adhere to the inner surface of the flow path of the ultrafiltration device 15 and the fine particle removing means such as the microfilter and nanofilter. It is. Furthermore, fine particles are particularly liable to stay in connection parts such as valves and joints constituting the flow path of the ultrafiltration device 15, and in the bent pipe part or the branch part. Since the retained fine particles are likely to cause a hunting phenomenon at the start of the production of ultrapure water, it is preferable to apply the vibration to such a connection portion or a curved pipe portion.

  Specifically, when vibration is applied to the flow path in the apparatus constituting the particulate removing means and the flow path within 1 m before and after (upstream side and downstream side) of the flow path in the apparatus, the vibration is applied. This is more effective for shortening the startup period of the ultrapure water production apparatus 1.

  During the start-up operation of the ultrapure water production apparatus 1, the non-regenerative mixed bed ion exchange resin apparatus 14 is connected by a bypass pipe (not shown) that bypasses the non-regenerative mixed bed ion exchange resin apparatus 14. It is preferable to bypass the gas dissolved water.

  Thus, after performing a washing | cleaning process, a vibration is stopped and the desorption process which discharges | emits the gas dissolved water in the ultrapure water manufacturing apparatus 1 is performed after that. For example, primary pure water containing neither hydrogen peroxide nor gas is supplied into the ultrapure water production apparatus 1, and the three-way valve V2 inserted in the circulation pipe 19 is connected to the drain pipe 18 from the primary pure water tank 10 side. Switching to the side, the gas-dissolved water is discharged out of the system via the drain pipe 18, and the de-pharmaceutical process is performed.

  Although it depends on the size of the ultrapure water production apparatus 1 and the flow rate of ultrapure water, the desorption process is performed for about 30 to 300 minutes. After the gas-dissolved water is sufficiently discharged from the system by the de-drug process, a flushing process is subsequently performed. In the flushing step, when the non-regenerative mixed bed ion exchange resin device 14 is bypassed, the flow path is switched from the bypass pipe to the non-regenerative mixed bed ion exchange resin device 14. The three-way valve V2 inserted in the circulation pipe 19 is switched from the drain pipe 18 side to the primary pure water tank 10 side to circulate ultrapure water. It is preferable that a part of the ultrapure water circulated in the system in the flushing process is discharged out of the ultrapure water production apparatus 1 system, for example, as concentrated water of the ultrafiltration device 15.

  During the flushing process, it is preferable to continuously measure the fine particles in the ultrapure water with the fine particle meter 25. When the inside of the ultrapure water production apparatus 1 is sufficiently cleaned, the measured value of the fine particles gradually decreases, and finally the fine particle count is 0 pcs. / L. In this case, the production of ultrapure water can be subsequently started. As the particle meter, one that can measure the number of particles online is preferable. For example, UDI-20 manufactured by Particle Measuring Systems can be used.

  On the other hand, when the fine particle cleaning in the cleaning process is not sufficiently performed, the number of fine particles is 0 pcs. In addition to not reaching / L, a phenomenon (hunting phenomenon) in which the number of fine particles temporarily increases intermittently occurs. This is presumed to be because there is an insufficiently cleaned portion in the flow path, and fine particles are discharged from this portion. In this case, since the quality of ultrapure water deteriorates, it may be necessary to continue flushing until the hunting phenomenon is reduced without starting production of ultrapure water.

  In this way, after the startup operation of the ultrapure water production apparatus 1 is performed, the production of ultrapure water is started.

  FIG. 2 is a block diagram schematically showing an ultrapure water production system 2 including the ultrapure water production apparatus 1 shown in FIG. 1 as a secondary pure water system. The ultrapure water production system 2 includes a pretreatment device 20 and a primary pure water system 30. A primary pure water tank 10 is connected to the subsequent stage of the primary pure water system 30, and an ultrapure water production apparatus (secondary pure water system) 1 is connected through the primary pure water tank 10.

  The production of ultrapure water by the ultrapure water production system 2 is performed as follows. For example, raw water such as city water, well water, and industrial water is sequentially processed by the pretreatment device 20 and the primary pure water system 30 to produce primary pure water.

  The pretreatment device 20 clarifies raw water to produce pretreatment water, and includes, for example, a coagulating sedimentation device and a sand filtration device. The primary pure water system 30 is for producing primary pure water by treating pretreated water, and includes an activated carbon device, a reverse osmosis membrane device, a cation exchange resin device, an anion exchange resin device, and a two-bed three-column ion. An exchange resin device, a vacuum deaeration device, an ultraviolet oxidation device, a mixed bed ion exchange resin device, a precision filter, and the like are appropriately selected. For example, the primary pure water has a specific resistance value of 17 MΩ · cm or more, a TOC concentration of 3 μg C / L or less, and the number of fine particles of 0.02 μm or more is 1 pcs. / ML or less.

  Next, the primary pure water is temporarily stored in the primary pure water tank 10 and then supplied to the secondary pure water system 1 (ultra pure water production apparatus 1 shown in FIG. 1) to produce ultra pure water. The produced ultrapure water is supplied to the use point 16.

  At this time, since the fine particles adhering to the inner surface of the flow path of the secondary pure water system 1 (ultra pure water production apparatus 1) are removed by the startup method of the above embodiment, even after the production of ultra pure water is started. The specific resistance value is 18.2 MΩ · cm or more, the TOC concentration is 1 μg C / L or less, and the number of fine particles is 1 pcs. Ultrapure water in which water quality of / mL or less is stably maintained can be supplied to the use point 16.

  In the above, a circulation piping system provided in a general ultrapure water production system, that is, a cleaning of a flow path of an ultrapure water production apparatus having a circulation piping for supplying ultrapure water to a POU (use place). Although the method has been described, the present invention is not limited to this. For example, usually, in an ultrapure water production system, a primary pure water production apparatus provided on the upstream side of the primary pure water tank 10 or a tertiary pure water provided on the downstream side of the ultrapure water production apparatus described above as necessary. The same can be applied to the start-up of the water production apparatus.

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

Example 1
A start-up operation was performed as follows using a secondary pure water system similar to the ultrapure water production apparatus shown in FIG.

The specifications of the apparatus used in the examples and comparative examples are as follows.
Heat exchanger (HEX)
Plate heat exchanger, made of titanium, manufactured by Nisaka Manufacturing Co., Ltd. Ultraviolet oxidation equipment (TOC-UV)
Product name: SUV-ST, manufactured by Nippon Photo Science Co., Ltd. Non-regenerative mixed-bed ion exchange resin device (Polisher)
A container with an inner diameter of 400 mm lined with polytetrafluoroethylene is mixed with a cation resin and an anion resin and filled with 210 L. Deaeration membrane device (MDG) manufactured by Nomura Micro Science Co., Ltd.
Product name: G284, polypore ultrafiltration device (UF)
Product name: OLT-6036HA, manufactured by Asahi Kasei Chemicals Co., Ltd. Online particle meter Product name: UDI-20, manufactured by Particle Measuring Systems

  First, a bypass pipe that bypasses the non-regenerative mixed bed ion exchange resin apparatus was provided to bypass the non-regenerative mixed bed ion exchange resin apparatus. Open the valve installed downstream of the primary pure water tank and operate the pump on the downstream side of the primary pure water tank to flow the primary pure water stored in the primary pure water tank into the secondary pure water system. It was. At this time, a circulation pipe for connecting the primary pure water tank from the use point was provided, and the primary pure water was circulated to the primary pure water tank. The discharge pressure of the pump was 0.3 MPa.

  In addition, a branch pipe is provided at the inlet side of the heat exchanger, and a chemical injection pump is connected to this, and the ultrapure water (hydrogen peroxide solution) in which hydrogen peroxide is dissolved by this chemical injection pump is used as the primary. It supplied to the primary pure water supplied from a pure water tank. Hydrogen peroxide concentration was supplied so that it might become 1 mass% with respect to the primary pure water made to flow through the ultrapure water production apparatus 1. The discharge pressure of the pump when supplying hydrogen peroxide was 0.3 MPa. Thereafter, the supply of hydrogen peroxide was stopped. Primary pure water circulation operation continued.

  At the same time, the supply water side, permeate side piping, valves, and branches of the flow path provided in the ultrafiltration device of the secondary pure water system were struck with a mallet to give vibration. The vibration was applied for 5 minutes, and the vibration by the wooden mallet was 1400 Gal as measured by a digital vibrometer OH-580A (manufactured by Testo Co., Ltd.). When applying the vibration, the discharge pressure of the pump was not changed and was set to 0.3 MPa.

  Next, after stopping the vibration, the three-way valve of the circulation pipe is switched from the primary pure water tank side to the drain pipe side, and ultrapure water containing hydrogen peroxide is drained out of the system. The primary pure water was supplied into the secondary pure water system, and the secondary pure water system was rinsed to carry out the de-drug process. Thereafter, the bypass pipe is switched to water flow to a non-regenerative mixed bed ion exchange resin apparatus, the three-way valve is switched from the drain pipe side to the primary pure water tank side, and the flushing process is performed for 60 hours. Started production of pure water. The pump discharge pressure during the production of ultrapure water was 0.3 MPa.

  The number of fine particles of 0.02 μm or more in the ultrapure water after the start of the flushing process was measured, and the number of occurrences of the hunting phenomenon on the second day, the fourth day, and the seventh day was measured. The results are shown in Table 1 together with the startup operation conditions. The number of fine particles of 0.02 μm or more increased compared to the previous and subsequent periods, and the number of times was counted as a hunting phenomenon. The number of fine particles during the hunting phenomenon is, for example, 10 pcs. / L or more.

(Example 2)
In this example, the start-up operation was performed in the same manner as in Example 1 except that the method of applying vibration to the flow path was changed from the method of hitting with a mallet to the method of hitting with a bare hand. The vibration was applied for 5 minutes, and the vibration when struck with a bare hand was 800 Gal as measured by the above-mentioned digital vibrometer.

(Example 3)
In this example, the method of applying vibration to the flow path was changed to a method of applying ultrasonic waves with an ultrasonic generator ET-30S-7 (manufactured by Shimada Rika Kogyo Co., Ltd.), and started up in the same manner as in Example 1. Drove. The vibration was applied for 5 minutes, and the ultrasonic vibration was 5000 Gal as measured by the digital vibration meter.

(Examples 4-11, Comparative Examples 1-8)
The startup operation was performed in the same manner as in Example 1 except that the startup operation conditions were changed as shown in Table 1. In these examples, the heat exchanger was operated as necessary to heat the primary pure water to the temperature shown in Table 1. In an example in which neither hydrogen peroxide nor gas was used, the startup operation was performed while operating the deaeration membrane device.
Moreover, in the example using nitrogen, while dissolving nitrogen using the nitrogen enclosed by the upper part of the primary pure water tank, and stopping the operation | movement of a membrane type deaerator, the primary which dissolved nitrogen Pure water was passed through the channel.

  After the start-up operation, production of ultrapure water was started in the same manner as in Example 1, and 0.02 μm or more in the produced ultrapure water on the second, fourth and seventh days after the start of the flushing process. Table 1 together with Example 1 shows the results of measuring the number of fine particles and measuring the number of occurrences of the hunting phenomenon.

  The relationship between the elapsed time and the number of fine particles from the cleaning process to the flushing process in Example 1 and Comparative Example 1 is shown in the graphs of FIGS.

  As shown in Table 1 and FIG. 3, in the method for starting the ultrapure water production apparatus of the embodiment of the present invention, the hunting phenomenon is suppressed and the number of fine particles is 1 pc. It can be seen that ultrapure water stably maintained at / mL or less was obtained. On the other hand, in Comparative Examples 1-8, it turns out that a hunting phenomenon is not suppressed.

  DESCRIPTION OF SYMBOLS 1 ... Ultrapure water production apparatus (secondary pure water system), 2 ... Ultrapure water production system, 10 ... Primary pure water tank (TK), 11 ... Heat exchanger (HEX), 12 ... Ultraviolet oxidation apparatus (TOC- UV), 13 ... Membrane type deaerator (MDG), 14 ... Non-regenerative mixed-bed ion exchange resin device (Polisher), 15 ... Ultrafiltration device (UF), 16 ... Use point (POU), 17 ... Treated water piping, 18 ... blow piping, 19 ... circulation piping, 20 ... pretreatment device, 30 ... primary pure water system, 25 ... particulate meter, P1 ... pump, V1 ... valve, V2 ... three-way valve.

Claims (10)

In the ultrapure water production apparatus that processes primary pure water to produce ultrapure water and supplies it to the place of use, the inside of the ultrapure water production apparatus system is cleaned prior to supplying the ultrapure water to the place of use. A method for starting up an ultrapure water production apparatus,
In the flow path of the ultrapure water production apparatus, pure water containing hydrogen peroxide or gas is retained or passed,
Apply vibration from outside to at least a part of the flow path,
A method for starting up an ultrapure water production apparatus, wherein fine particles adhering to the inner surface of the flow path are removed.   The method for starting up an ultrapure water production apparatus according to claim 1, wherein the vibration is 600 gal or more.   The method for starting up an ultrapure water production apparatus according to claim 1 or 2, wherein the gas is at least one selected from nitrogen, carbon dioxide and hydrogen.   The water pressure of the pure water containing hydrogen peroxide or gas flowing through the flow path is equal to or higher than the water pressure when producing ultrapure water in the ultrapure water production apparatus, and the water pressure when producing ultrapure water. The method for starting up the ultrapure water production apparatus according to any one of claims 1 to 3, characterized in that the ratio is 2 times or less.   5. The apparatus for producing ultrapure water according to claim 1, wherein the temperature of the pure water containing hydrogen peroxide or gas flowing through the flow path is 10 ° C. to 45 ° C. 5. How to start up. The ultrapure water production apparatus includes a fine particle removing unit,
6. The method for starting up an ultrapure water production apparatus according to any one of claims 1 to 5, wherein the vibration is applied to a flow path of the particulate removing means.   7. The vibration according to claim 1, wherein the vibration is applied to one or more types selected from a joint, a valve, a curved pipe portion, and a branch portion constituting a flow path of the ultrapure water production apparatus. How to start up ultrapure water production equipment.   The method for starting up an ultrapure water production apparatus according to any one of claims 1 to 7, wherein oxygen or the gas generated from the hydrogen peroxide is dissolved in the primary pure water with supersaturation.   The method for starting up the ultrapure water production apparatus according to any one of claims 1 to 8, wherein bubbles are contained in the pure water containing hydrogen peroxide or gas.   The pure water containing the hydrogen peroxide or gas is discharged outside the ultrapure water production system by passing pure water through the flow path after removing the fine particles. 10. A method for starting up an ultrapure water production apparatus according to any one of items 9 to 9.

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