CN112770825A

CN112770825A - Method for starting ultrapure water production apparatus and ultrapure water production apparatus

Info

Publication number: CN112770825A
Application number: CN201980063396.5A
Authority: CN
Inventors: 松井恭则
Original assignee: Nomura Micro Science Co Ltd
Current assignee: Nomura Micro Science Co Ltd
Priority date: 2018-11-22
Filing date: 2019-11-11
Publication date: 2021-05-07
Anticipated expiration: 2039-11-11
Also published as: CN112770825B; KR20210091115A; WO2020105494A1; JP7171386B2; TW202039065A; JP2020081957A

Abstract

The start-up period of the pure water production apparatus is shortened. A method for starting up an ultrapure water production system according to the present invention is a method for starting up an ultrapure water production system including a water treatment system including at least a flow path through which water to be treated flows and an ultrafiltration membrane device provided in the flow path and performing water treatment on the water to be treated at a stage preceding a point of use, the method including: a step of providing a filter device temporarily placed in a stage preceding the ultrafiltration membrane device in the flow path; a step of cleaning the water treatment system by starting water supply along the flow path after the temporary filter device is set; and separating the temporarily placed filter device from the ultrapure water production apparatus after a predetermined period of time has elapsed from the start of the cleaning by the water supply.

Description

Method for starting ultrapure water production apparatus and ultrapure water production apparatus

Technical Field

The present invention relates to a method for starting an ultrapure water production system, which is used when, for example, the ultrapure water production system is newly installed and started, and an ultrapure water production system to which the starting method can be applied.

Background

In an ultrapure water production apparatus used in a semiconductor production process or the like, ultrapure water is obtained by water treatment of water to be treated flowing through a flow path by a water treatment system including the flow path of water to be treated which is directed to a point of use (use point) and various treatment apparatuses. Such an ultrapure water production apparatus mainly includes a primary pure water production unit and a secondary pure water production unit. The primary pure water production unit produces primary pure water using, for example, a pretreatment unit that removes suspended substances in raw water, and a reverse osmosis membrane device or an ion exchange device that removes Total Organic Carbon (TOC) components or ionic components in the pretreatment water. On the other hand, the secondary pure water producing unit produces secondary pure water (ultrapure water) by removing particles, colloidal substances, organic substances, metals, anions, and the like remaining in the primary pure water.

Here, when, for example, an assembly work of the ultrapure water production apparatus is performed at an installation site thereof in order to newly install and start the ultrapure water production apparatus, there are problems such as contamination of particles, viable bacteria, and total organic carbon components into the water treatment system, and elution of metal components from pipes constituting a flow path of water to be treated. Therefore, as a countermeasure, the water treatment system in the ultrapure water production apparatus is cleaned in advance before the normal operation of the ultrapure water production apparatus (for example, see patent document 1).

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2004-122020

Disclosure of Invention

Problems to be solved by the invention

However, even after the above-described cleaning is continued for a long time, the ultrapure water produced by the ultrapure water production apparatus may not be within the expected production specifications. For example, when the connection points of piping and the like in the ultrapure water production system are connected in a complicated manner, or when there is a problem in the cleanliness of the environment in which the ultrapure water production system is installed, metal particles, sand, and the like having relatively large particle diameters may be trapped in the ultrafiltration membrane apparatus or the like disposed at the front stage of the point of use. At this time, the elution of components such as metal particles continues for a long period of time in the water treatment system, and as a result, the water quality of the produced ultrapure water is in a state of continuously deteriorating.

The present invention has been made to solve the above problems, and an object thereof is to provide a method for starting an ultrapure water production apparatus and an ultrapure water production apparatus, which can shorten the start-up period of the ultrapure water production apparatus.

Means for solving the problems

A method for starting up an ultrapure water production system according to the present invention is a method for starting up an ultrapure water production system including a water treatment system including at least a flow path through which water to be treated flows and an ultrafiltration membrane device provided in the flow path and performing water treatment on the water to be treated at a stage preceding a point of use, the method including: a step of providing a filter device temporarily placed in a stage preceding the ultrafiltration membrane device in the flow path; cleaning the water treatment system by starting water supply along the flow path after the temporary filter device is installed; and separating the temporarily placed filter device from the ultrapure water production apparatus after a predetermined period of time has elapsed from the start of the cleaning by the water supply.

Preferably said cleaning comprises a germicidal treatment. Further, it is preferable that the step of separating is followed by a step of starting water supply along the flow path and performing water treatment until ultrapure water within a desired production specification is obtained. Preferably, the ultrapure water production apparatus further comprises a tank on the flow path upstream of the temporarily placed filter device, and the flow path has a circulation line that returns to the tank after passing through the ultrafiltration membrane device, and the water to be supplied is circulated through the circulation line during the cleaning. Further, it is desirable that the predetermined period is a period in which the number of cycles calculated from the amount of water and the flow rate in the circulation line is, for example, 0.5 to 2200 times as the cleaning is started.

On the other hand, an ultrapure water production apparatus of the present invention comprises: a flow path through which water to be treated flows; an ultrafiltration membrane device provided in the flow path and configured to perform water treatment on the water to be treated at a stage preceding a point of use; and a filter mounting/demounting mechanism provided at a stage preceding the ultrafiltration membrane apparatus on the flow path and capable of mounting/demounting a temporarily placed filter apparatus to/from the flow path.

Preferably, the temporarily placed filter device is, for example, a microfiltration membrane device. Further, it is preferable that the flow path is constituted by a first pipe, and the filter attachment/detachment mechanism includes a plurality of joints detachably connecting a second pipe constituting a branch flow path that temporarily branches from the flow path and joins on a downstream side of the flow path via the temporarily placed filter device to the first pipe, and a first opening/closing valve disposed between a position where the second pipe branches and a position where the second pipe joins in the first pipe. Further, it is preferable that a pair of second on-off valves and the like are provided in the second pipe, for example, in front of and behind the temporarily placed filter device.

Effects of the invention

According to the present invention, it is possible to provide a method for starting an ultrapure water production apparatus and an ultrapure water production apparatus, which can shorten the start-up period of the ultrapure water production apparatus.

Drawings

Fig. 1 is a block diagram schematically showing the configuration of an ultrapure water production apparatus according to an embodiment of the present invention.

FIG. 2 is a block diagram showing the configuration of a secondary pure water production unit provided in the ultrapure water production apparatus of FIG. 1.

FIG. 3 is a view showing a state where the temporarily placed microfiltration membrane apparatus is separated from the secondary pure water production unit of FIG. 2.

FIG. 4 is a flowchart showing a method of starting up the ultrapure water production system according to the embodiment of the present invention.

Fig. 5 is a diagram showing a configuration example in which a part of a circulation line of the water to be treated is different from that of the secondary pure water production unit of fig. 2.

FIG. 6 is a view illustrating another separation state different from that of the microfiltration membrane apparatus of FIG. 3.

Detailed Description

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

As shown in fig. 1, an ultrapure water production apparatus 10 according to the present embodiment is an apparatus for obtaining ultrapure water by water treatment of water to be treated, and includes a water treatment system 15 including a pretreatment unit 12, a primary pure water production unit 14, a flow path 31 for water to be treated, a tank 16, and a secondary pure water production unit 18. The pretreatment unit 12 introduces tap water, well water, industrial water, and the like as raw water. The pretreatment unit 12 has an appropriate configuration according to the quality of raw water and the like, and removes suspended substances from the raw water to generate pretreatment water. The pretreatment unit 12 includes, for example, a sand filter, a microfiltration device, and the like, and also includes a heat exchanger and the like for adjusting the temperature of the water to be treated as necessary.

The primary pure water production unit 14 removes organic components, ionic components, dissolved gases, and the like in the pretreatment water to produce primary pure water, and supplies the primary pure water to a Tank (TK) 16. The primary pure water production unit 14 is configured by appropriately combining one or more of a reverse osmosis membrane device, an ion exchange device (a cation exchange device, an anion exchange device, a mixed bed ion exchange device, and the like), an ultraviolet oxidation device, and a degassing device (a vacuum degassing device, a degassing membrane device, and the like), for example. The primary pure water has a Total Organic Carbon (TOC) concentration of 5 [ mu ] gC/L or less and a specific resistance of 17M [ omega ] cm or more. The tank 16 stores primary pure water, and supplies a required amount thereof to the secondary pure water production unit 18.

On the other hand, the secondary pure water production unit 18 removes impurities from the primary pure water produced by the primary pure water production unit 14 to produce secondary pure water as ultrapure water, and supplies the ultrapure water to a Point Of Use (POU) 20, which is a Point Of Use. The flow path 31 is a flow path through which water to be treated flows, and conveys water to be treated, which has been treated by the pretreatment unit 12, the primary pure water production unit 14, and the secondary pure water production unit 18 constituting the water treatment system 15, to the point of use 20. As shown in fig. 1 and 2, the tank 16 is disposed on the upstream side of a microfiltration membrane device (temporary filter device) 27 described later on the flow path 31. The flow path 31 further includes a circulation line 31b that returns to the tank 16 after passing through the ultrafiltration membrane apparatus 28 described later. In the example of fig. 1 and 2, the circulation line 31b is a path returning from the position of the most downstream use point 20 to the position of the use point 20 via the tank 16 and the secondary pure water production unit 18. That is, the remaining ultrapure water having passed through the use point 20 is recovered by the tank 16 through the circulation line 31b of the flow path 31.

Specifically, as shown in fig. 2 and 3, the secondary pure water producing unit 18 includes a circulation pump (treated water supply pump) 22, a Heat Exchanger (HEX: Heat Exchanger)23, an ultraviolet oxidation device (TOC-UV)24, a Membrane degasifier (MDG: Membrane degasifier)25, an ion polisher (Polisher)26, a filter attachment/detachment mechanism 30, an Ultrafiltration Membrane (UF: Ultrafiltration Membrane) device 28, and a particle meter 29.

The circulation pump 22 is a treated water supply pump that supplies the treated water (primary pure water) contained in the tank 16 to the heat exchanger 23. The heat exchanger 23 adjusts the temperature of the water to be treated supplied from the circulation pump 22. At this time, the temperature of the water to be treated is preferably adjusted to, for example, 25. + -. 3 ℃ by the heat exchanger 23.

The ultraviolet oxidation apparatus 24 irradiates the water to be treated (primary pure water) whose temperature has been adjusted by the heat exchanger 23 with ultraviolet rays, and decomposes and removes a trace amount of organic substances in the water to be treated. The ultraviolet oxidation device 24 has, for example, an ultraviolet lamp and generates ultraviolet rays having a wavelength of about 185 nm. The ultraviolet oxidation device 24 may generate ultraviolet rays having a wavelength of about 254 nm. When the water to be treated is irradiated with ultraviolet rays in the ultraviolet oxidation apparatus 24, the ultraviolet rays decompose water molecules to generate hydroxyl groups, and the hydroxyl groups oxidize and decompose organic substances in the water to be treated.

The membrane degasifier 25 is a device that depressurizes the secondary side of the gas permeable membrane to remove only dissolved gas in the water to be treated flowing through the primary side by passing through the secondary side. The ion polisher 26 is a non-regenerative mixed bed ion exchanger having a mixed bed type ion exchange resin in which a cation exchange resin and an anion exchange resin are mixed, and configured to adsorb and remove a small amount of cation components and anion components in the water to be treated.

A filter attachment/detachment mechanism (filter attachment/detachment mechanism) 30, which will be described later, is provided in a flow path 31 of the water to be treated at a stage (immediately before) of the ultrafiltration membrane apparatus 28, and the microfiltration membrane apparatus 27 can be attached to and detached from the flow path 31. The ultrafiltration membrane apparatus 28 is provided upstream (immediately before) of the most downstream point of use 20 on the flow path 31.

The ultrafiltration membrane apparatus 28 has a plurality of hollow fiber modules each having a flow rate of 5m³More than h. Typically 10m³More than h. The ultrafiltration membrane apparatus 28 provided in the flow path 31 further treats the water to be treated from the ion polisher 26 (or the microfiltration membrane apparatus 27 when attached) at a stage before the point of use 20, thereby treating the water to have a particle diameter of, for example, 50nm or moreThe fine particles above were removed to obtain ultrapure water (secondary pure water).

Here, in the ultrapure water production apparatus 10 of the present embodiment, the number of particles having a particle diameter of 50nm or more is 200/L or less, the total organic carbon concentration is 1. mu. gC/L or less, and the specific resistance is 18 M.OMEGA.cm or more, in the ultrapure water (ultrapure water satisfying the expected water quality conditions) within the production specifications. The particle size meter 29 measures the particle size of particles in the secondary pure water (ultrapure water) after being treated with water by the ultrafiltration membrane apparatus 28.

Next, the filter attachment/detachment mechanism 30 and the temporary microfiltration membrane apparatus 27 will be described in detail. As shown in fig. 2 and 3, the filter attachment/detachment mechanism 30 includes a plurality of

joints

36, 37, 41, and 42, and an opening/closing valve (first opening/closing valve) 33. On the other hand, the Microfiltration Membrane (MF) apparatus 27 includes a Membrane having a pore size larger than that of the Membrane of the subsequent ultrafiltration Membrane apparatus 28. The pore size of the microfiltration membrane is not particularly limited, but the microfiltration membrane preferably has filtration accuracy for separating particles having a particle size of 0.2 μm or more. This is because the cause of the inhibition of the early start-up in the present invention is relatively large particles, and therefore a microfiltration membrane having a relatively large pore size is sufficient. Further, such a microfiltration membrane has a substantially reduced number of membranes and a reduced pressure loss, and therefore has a good water permeability.

The microfiltration membrane may be a surface filtration membrane or a depth filtration membrane. The latter depth filtration type microfiltration membrane is more preferable because it can secure a large flow rate of water and thus the number of membranes to be used is small and inexpensive.

In addition, the depth filtration type microfiltration membrane is generally used on the front stage side of the ultrapure water production apparatus, for example, in a protective filter of a reverse osmosis membrane provided in the primary pure water production unit or in a pretreatment unit, but when applied to the secondary pure water production unit as in the present embodiment, the pore diameter is too large in the depth filtration type microfiltration membrane, and therefore, it is considered that removal of fine particles cannot be expected, and the effect is unexpected in start-up.

As the microfiltration membrane of the surface filtration type, HDCII series, Polyfine II series (manufactured by Pall corporation) and the like can be suitably used, and as the microfiltration membrane of the depth filtration type, Betafine series (manufactured by 3M japan corporation), Profile II, Nexus series, Profile UP series (manufactured by Pall corporation) and the like can be suitably used.

That is, the microfiltration membrane apparatus 27 can capture metal particles (foreign substances) released from, for example, pipes in the ultrapure water production apparatus 10, sand mixed into the water treatment system 15 from the installation environment of the ultrapure water production apparatus 10, and the like.

The microfiltration membrane apparatus 27 is a Temporary placement (Temporary) protective Filter (Temporary Guard Filter) apparatus. The microfiltration membrane apparatus 27 is attached to the ultrapure water production apparatus 10 when the ultrapure water production apparatus 10 is newly installed and started up, for example, but is detached (removed) from the ultrapure water production apparatus 10 via the filter attachment/detachment mechanism 30 after the start-up of the ultrapure water production apparatus is completed.

Here, the flow path 31 of the water to be treated is constituted by a pipe 31 a. In addition, in order to temporarily place the microfiltration membrane apparatus 27, a pipe (second pipe) 32a is prepared for constituting a branch flow path 32 which temporarily branches from the flow path 31 and joins on the downstream side of the flow path 31 via the microfiltration membrane apparatus 27. That is, the microfiltration membrane apparatus 27 is inserted in the middle of the pipe 32 a.

As shown in fig. 2 and 3, the

joints

41 and 42 detachably connect the pipe 32a to the pipe 31 a. The

joints

36 and 37 also detachably connect the pipe 32a to the pipe 31 a. Specifically, the

joints

36 and 37 can detach the pipe 32a from the pipe 31a together with the opening/

closing valves

34 and 35. In the present embodiment, as shown in FIG. 3, a mode in which the pipe 32a and the temporarily placed microfiltration membrane apparatus 27 are removed from the pipe 31a via the

joints

41 and 42 is mainly exemplified.

The on-off valve 33 is provided between the branching position and the merging position in the pipe 31a, and switches between passing and blocking (non-passing) of water to the inside of the pipe 31 a. Further, a pair of opening/closing valves (second opening/closing valves) 34 and 35 are provided in the pipe 32a before and after the temporary microfiltration membrane apparatus 27. The opening/

closing valves

34, 35 switch between passing and blocking (non-passing) water to the inside of the pipe 32 a.

Accordingly, as shown in fig. 2, for example, when water is fed through a path that is branched from the flow path 31 and joins via the branch flow path 32 and the microfiltration membrane apparatus 27 on the downstream side of the flow path 31 in a state where the microfiltration membrane apparatus 27 is provided, the on-off valve 33 is closed, and the on-off

valves

34 and 35 are opened. Further, when water is not supplied to the flow path 31 through the branch flow path 32 and the microfiltration membrane apparatus 27, including a state in which the microfiltration membrane apparatus 27 is separated (removed) from the ultrapure water production apparatus 10 as shown in FIG. 3 or a state in which the microfiltration membrane apparatus 27 is provided as shown in FIG. 2, the on-off valve 33 is opened, and the on-off

valves

34 and 35 are closed.

In this case, the section from the joint 36 to the on-off valve 34 and the section from the on-off valve 35 to the joint 37 become dead spaces, and there is a concern that the water quality may deteriorate due to the water retention. Therefore, even when a thin pipe is attached instead of the separated pipe 32a after the temporarily placed microfiltration membrane apparatus 27 is removed together with the pipe 32a, a small flow rate flows from the joint 36 to the joint 37, and water retention can be prevented.

Next, a method for starting up the ultrapure water production apparatus 10 according to the present embodiment (a method for producing ultrapure water by the ultrapure water production apparatus 10) will be described based on the flowchart shown in fig. 4, in addition to fig. 1 to 3. When the ultrapure water production apparatus 10 is started up, first, the ion polisher 26, the ultrafiltration membrane apparatus 28, the flow path 31 (the pipe 31a), and the like are assembled, and the temporarily placed microfiltration membrane apparatus 27 is set (assembled) to the body of the ultrapure water production apparatus 10 via the filter mounting/demounting mechanism 30 as shown in fig. 2 and 4 (S1).

After the microfiltration membrane apparatus 27 is installed, the on-off valve 33 on the pipe 31a is closed, and the on-off

valves

34 and 35 on the pipe 32a (branch flow path 32) are opened. After the precise filtration membrane apparatus 27 is set in this manner, for example, by starting water supply from the front stage of the pretreatment unit 12 along the flow path 31 including the branch flow path 32 and the circulation line 31b, as shown in fig. 1, 2, and 4, the water treatment system 15 including the pretreatment unit 12, the devices in the primary pure water production unit 14, the flow path 31, the ion polisher 26, the ultrafiltration membrane device 28, and the like is cleaned (S2). At this time, for example, metal particles released from the pipes in the ultrapure water production apparatus 10, sand mixed into the water treatment system 15, and the like are captured by the microfiltration membrane apparatus 27.

In the above washing, the water for water supply (washing water) for washing the water treatment system 15 may be primary pure water. Such washing is performed for a predetermined period of time or longer, in which the water for washing (washing water) that has passed through the position of the use point 20 following the start of the washing is returned to the position of the use point 20 at least once around the circulation line 31 b.

The number of cycles calculated from the amount of water and the flow rate in the circulation line 31b following the start of the washing is preferably 0.5 to 2200, more preferably 1 to 1000, and still more preferably 40 to 500. The water passage time is preferably 0.25 to 1000 hours, more preferably 0.5 to 720 hours, and further preferably 24 to 170 hours. Further, since foreign matter is contained in a large amount in the front stage side of the circulation system, the effect is obtained even if the number of cycles is 0.5, but the effect becomes large if it exceeds 1.

When the number of cycles or the water passage time is small, foreign matters cannot be sufficiently captured by the microfiltration membrane, and therefore the effect of shortening the start-up time cannot be obtained. On the other hand, when the number of cycles or the water passage time is large, the foreign matter trapped in the microfiltration membrane is, for example, crushed and flows to the subsequent stage, and therefore the effect of shortening the start-up time is not obtained. Further, although the optimum conditions vary depending on the length, diameter, number of branches, and the like of the pipes to be installed, the cleaning is performed under the conditions selected from the above-described ranges.

Here, the predetermined period may be, for example, one week. In the cleaning, the respective devices in the pretreatment unit 12, the primary pure water production unit 14, and the secondary pure water production unit 18 are set to an operating state. By the cleaning as described above, for example, metal particles released from the pipes in the ultrapure water production system 10 are captured by the microfiltration membrane apparatus 27.

After a predetermined period of time has elapsed from the start of cleaning (YES in S3), the microfiltration membrane apparatus 27 in which the metal particles and the like have been trapped is removed (separated) from the ultrapure water production apparatus 10 (S4). Specifically, after the water supply is stopped, the opening/

closing valves

34 and 35 on the pipe 32a (branch flow path 32) are closed. Further, as shown in FIG. 3, the temporarily placed microfiltration membrane apparatus 27 is removed together with the pipe 32a via the

joints

41 and 42.

After the microfiltration membrane apparatus 27 is removed, the on-off valve 33 is opened, and the water supply (supply of raw water to the pretreatment unit 12) along the flow path 31 including the circulation line 31b is started while each of the pretreatment unit 12, the primary pure water production unit 14, and the secondary pure water production unit 18 is set in an operating state, and water treatment by the water treatment system 15 is performed (S5). Further, the cleaning can be performed without stopping the water supply between the operations of the step of removing (S4) and the step of performing the water treatment (S5). In this case, the opening/closing valve 33 is opened, and simultaneously or subsequently, the opening/

closing valves

34, 35 are closed. Then, the microfiltration membrane apparatus 27 may be detached. This water treatment is continued until ultrapure water (water quality of ultrapure water conforming to the specification (spec in)) which is obtained within the production specifications described above as an example and which is within the expected production specifications is obtained (S6). At this time, the particle size of the particles in the secondary pure water (ultrapure water) was measured by the fine particle meter 29 as to whether or not the particle size was within the production specification. Thereafter, when ultrapure water within the production specifications is obtained (YES in S6), the ultrapure water production apparatus 10 is started up (S7).

Here, in the method for starting up the ultrapure water production apparatus 10 of the present embodiment, the cleaning in the water treatment system 15 is started in a state where the microfiltration membrane apparatus 27 is provided at the preceding stage (immediately before) of the ultrafiltration membrane apparatus 28, and after a predetermined period of time has elapsed, the microfiltration membrane apparatus 27 in which, for example, metal particles, sand, or the like are captured is removed (separated) from the ultrapure water production apparatus 10, and then water treatment is performed, so that the above-described metal particles, sand, or the like can be removed from the water treatment system 15. Therefore, according to the method for starting up the ultrapure water production apparatus 10 of the present embodiment, it is possible to avoid a situation in which the elution of components such as sand and metal particles that may be present in the water treatment system 15 continues and the quality of the ultrapure water is lowered. That is, in the water treatment after the removal of the microfiltration membrane apparatus 27, ultrapure water which is within the desired production specification is quickly obtained, and thereby the start-up period of the ultrapure water production apparatus 10 can be shortened.

In addition, in one of the stages of this operation, the sterilization operation in the secondary pure water production unit 18 by hydrogen peroxide or the like can be performed. In this case, hydrogen peroxide is added to the system (water treatment system 15) except for the ion polisher 26 and/or the ultrafiltration membrane apparatus 28 by using a line (not shown) that bypasses the ion polisher 26 and/or the ultrafiltration membrane apparatus 28, and by using a branch valve provided on one of the components in the secondary pure water production unit 18, for example, on the suction side of the tank 16 or the pump 22. Thereafter, a predetermined time cycle is performed. After the sufficient sterilization treatment, the hydrogen peroxide water is discharged from one of the sites. After the hydrogen peroxide is absent from the system, the bypass of the ion polisher 26 and/or ultrafiltration membrane apparatus 28 is stopped.

In the starting method of the ultrapure water production system of the present invention, the cleaning of the water treatment system 15 including the ion polisher 26 is performed without filling the ion polisher 26 with the ion exchange resin, and the cleaning operation may be stopped in one of the stages to fill the ion polisher 26 with the ion exchange resin.

Further, although the above operation has been described using the circulation line 31b including the use point 20, as shown in fig. 5, a circulation line 31c bypassing the use point 20 may be used. In this case, in one of the stages, an operation is performed to include the use point 20 in the circulation line. In order to shorten the startup time, it is preferable to select a startup method in the circulation line 31b including the use point 20.

Further, in order to supplement the water supply by the circulation pump 22, as shown in fig. 5, a booster pump 43 may be provided between the ion polisher 26 and the joint 36. The booster pump 43 may be added to the secondary pure water producing unit illustrated in fig. 2 and 3 or the secondary pure water producing unit illustrated in fig. 6 described later.

On the other hand, it was verified that, when the ultrapure water production apparatus 10 was subjected to cleaning with cleaning water using an ultrapure water production apparatus not provided with the filter apparatus (microfiltration membrane apparatus 27) temporarily placed as described above, and water treatment was performed, ultrapure water that was within the production specifications could not be obtained even if such cleaning and water treatment were continued for 4 months, for example. In this case, the metal powder, sand, or the like is captured by the hollow fiber module in the ultrafiltration membrane apparatus 28, and the captured foreign matter is not collected in the production specification because the foreign matter is crushed over time and flows to the subsequent stage. Therefore, by exchanging all the hollow fiber modules in the ultrafiltration membrane apparatus 28 for new ones and performing water treatment again, ultrapure water which is collected in the production specifications is finally obtained.

It was also verified that, even when the ultrapure water production apparatus having the same apparatus configuration as the ultrapure water production apparatus 10 was used and the microfiltration membrane apparatus 27 was mounted, and cleaning with cleaning water and water treatment were carried out, ultrapure water that was within the production specifications could not be obtained even if such cleaning and water treatment were continued for 3 months, for example. In this case, for example, metal powder or sand having a size that can be visually observed is captured in the microfiltration membrane apparatus 27, and after the microfiltration membrane apparatus 27 is removed, the water treatment is performed again, and ultrapure water within the production specifications is finally obtained.

In contrast, according to the method for starting up the ultrapure water production apparatus 10 of the present embodiment, it was verified that ultrapure water within the production specifications was immediately obtained by removing the microfiltration membrane apparatus 27 capturing, for example, metal particles, sand, or the like from the ultrapure water production apparatus 10 after 1 week of cleaning using a cleaning liquid containing hydrogen peroxide in a state where the microfiltration membrane apparatus 27 was installed, and then performing water treatment.

As described above, according to the starting method of the ultrapure water production apparatus 10 of the present embodiment (and the ultrapure water production apparatus 10 to which the starting method can be applied), cleaning and water treatment are performed in which the temporarily placed filter apparatus (the microfiltration membrane apparatus 27) and the filter attachment/detachment mechanism 30 are effectively used, and thus the starting period of the ultrapure water production apparatus 10 can be shortened. In addition, instead of the filter attachment/detachment mechanism 30 shown in fig. 3, as shown in fig. 6, the filter attachment/detachment mechanism 40 can be applied to an ultrapure water production apparatus and a method for starting the same. In the case of this filter attachment/detachment mechanism 40, after the opening/

closing valves

34, 35 are closed, the pipe 32 (branch flow path 32a) and the microfiltration membrane device 27 are removed (separated) together with the opening/

closing valves

34, 35 via the

joints

36, 37. After the temporarily placed microfiltration membrane apparatus 27 is removed from the ultrapure water production apparatus 10 together with the opening/

closing valves

34, 35 and the pipe 32a, for example, closing plugs (stop valves) 38, 39 and the like are attached to the

joints

36, 37 at the positions where the pipe 32a is attached.

The present invention has been described above in more detail with reference to the embodiments, but the present invention is not limited to the embodiments as such, and various modifications can be made in the implementation stage without departing from the scope of the present invention. For example, some of the structural elements may be deleted from all the structural elements shown in the embodiments, and a plurality of the structural elements disclosed in the above embodiments may be combined as appropriate.

Description of the reference symbols

10 … … ultrapure water production apparatus, 12 … … pretreatment unit, 14 … … primary pure water production unit, 15 … … water treatment system, 16 … … Tank (TK), 18 … … secondary pure water production unit, 20 … … point of use (POU), 22 … … circulating pump, 23 … … Heat Exchanger (HEX), 24 … … ultraviolet oxidation unit (TOC-UV), 25 … … Membrane Degasser (MDG), 26 … … ion polisher, 27 … … microfiltration membrane unit (MF), 28 … … ultrafiltration membrane Unit (UF), 29 … … micrometerer, 30, 40 … … filter attachment/detachment mechanism, 31 … … flow path, 31a … … piping (first piping), 31b, 31c … … circulating line, 32 … … branch flow path, 32a … … piping (second piping), 33 … … on-off valve (first on-off valve), 34, 35 … … on-off valve (second on-off valve), 36, 37, 41, 42 … … tabs, 38, 39 … … block the stopper.

Claims

1. A method for starting an ultrapure water production system, which comprises a water treatment system including at least a flow path through which water to be treated flows and an ultrafiltration membrane device provided in the flow path and treating the water to be treated at a stage preceding a point of use,

the method for starting up the ultrapure water production apparatus comprises:

a step of providing a filter device temporarily placed in a stage preceding the ultrafiltration membrane device in the flow path;

a step of cleaning the water treatment system by starting water supply along the flow path after the temporary filter device is set; and

and a step of separating the temporarily placed filter device from the ultrapure water production apparatus after a predetermined period of time has elapsed from the start of the cleaning by the water supply.

2. The starting method for the apparatus for manufacturing ultrapure water according to claim 1, wherein,

the cleaning comprises a sterilization treatment.

3. The method for starting up the apparatus for manufacturing ultrapure water according to claim 1 or 2, further comprising:

and a step of starting water supply along the flow path after the separation step, and performing water treatment until ultrapure water within a desired production specification is obtained.

4. The starting-up method of the ultrapure water manufacturing apparatus according to any one of claims 1 to 3, wherein,

the ultrapure water production apparatus further comprises a tank on the upstream side of the temporarily placed filter device in the flow path,

the flow path having a recycle line returning to the tank after passing through the ultrafiltration membrane device,

in the washing, the water to be sent is circulated in the circulation line.

5. The starting method of the apparatus for producing ultrapure water according to claim 4, wherein,

the predetermined period is a period in which the number of cycles calculated from the amount of water and the flow rate in the circulation line is 0.5 to 2200 times as the cleaning is started.

6. The starting-up method of the ultrapure water manufacturing apparatus according to any one of claims 1 to 5, wherein,

the temporarily placed filter device has a filtration accuracy of separating particles of 0.2 μm or more.

7. The starting-up method of the ultrapure water manufacturing apparatus according to any one of claims 1 to 6, wherein,

the ultrafiltration membrane apparatus has a plurality of hollow fiber type modules,

the flow rate of water passing through each of the hollow fiber modules is 10m³More than h.

8. The starting-up method of the ultrapure water manufacturing apparatus according to any one of claims 1 to 7, wherein,

the number of particles having a particle diameter of 50nm or more, which are contained in ultrapure water within a desired production specification, is 200/L or less.

9. An ultrapure water production apparatus, comprising:

a flow path through which water to be treated flows;

an ultrafiltration membrane device provided in the flow path and configured to perform water treatment on the water to be treated at a stage preceding a point of use; and

and a filter mounting/demounting mechanism provided at a stage preceding the ultrafiltration membrane apparatus on the flow path, and capable of mounting/demounting a temporarily placed filter apparatus to/from the flow path.

10. The apparatus for manufacturing ultrapure water according to claim 9, wherein,

the temporarily placed filter device is a microfiltration membrane device.

11. The apparatus for producing ultrapure water according to claim 9 or 10, wherein,

the flow path is constituted by a first pipe,

the filter mounting/dismounting mechanism includes:

a plurality of joints that detachably connect a second pipe constituting a branch flow path to the first pipe, the branch flow path being temporarily branched from the flow path and merging on a downstream side of the flow path via the temporarily placed filter device; and

and a first on-off valve provided between the branching position and the merging position in the first pipe.

12. The apparatus for producing ultrapure water according to claim 11, wherein,

the second pipe is provided with a pair of second opening/closing valves respectively in front and rear of the temporarily placed filter device.

13. The ultrapure water production apparatus according to any one of claims 9 to 12, wherein,

a tank is further provided on the upstream side of the temporarily placed filter device in the flow path,

the flow path has a recycle line that returns to the tank after passing through the ultrafiltration membrane device.