TWI851623B - Start-up method of ultrapure water production device and ultrapure water production device - Google Patents

Abstract

In order to shorten the startup period of pure water production equipment. The startup method of the ultrapure water production device of the present invention is provided with a water treatment system, which at least includes: a flow path for allowing the treated water to flow through, and an ultrafiltration membrane device installed on the aforementioned flow path and treating the aforementioned treated water at the front end of the use point. The startup method has: a step of installing a temporary filter device at the front end of the aforementioned ultrafiltration membrane device on the aforementioned flow path, a step of cleaning the aforementioned water treatment system by starting to send water along the aforementioned flow path after installing the aforementioned temporary filter device, and a step of separating the aforementioned temporary filter device from the aforementioned ultrapure water production device after a predetermined period of time has passed since the start of the aforementioned water sending and cleaning.

Description

Start-up method of ultrapure water production device and ultrapure water production device

The present invention relates to a startup method of an ultrapure water production device used when starting up an ultrapure water production device, for example, a new ultrapure water production device, and an ultrapure water production device that can use the startup method.

The ultrapure water production device used in the semiconductor manufacturing process, etc., obtains ultrapure water by treating the treated water flowing in the flow path through a water treatment system including a flow path for the treated water to the use point (place of use) and various treatment devices. This ultrapure water production device mainly has a primary pure water production section and a secondary pure water production section. The primary pure water production section uses, for example, a reverse osmosis membrane device or an ion exchange device to remove the total organic carbon (TOC) component and ion component in the pre-treated water before removing the suspended matter in the raw water. On the other hand, the secondary pure water production department removes the microparticles, colloids, organic matter, metals, anions, etc. remaining in the primary pure water to produce secondary pure water (ultrapure water).

Here, in order to start up a new ultrapure water production device, for example, when the ultrapure water production device is assembled at its installation site, problems such as the mixing of microparticles, bacteria, and total organic carbon components in the water treatment system and the dissolution of metal components from the pipes constituting the flow path of the treated water may occur. Therefore, as a countermeasure, the water treatment system in the ultrapure water production device is cleaned in advance before the normal operation of the ultrapure water production device (for example, refer to Patent Document 1). [Prior Art Document] [Patent Document]

Patent document 1: Japanese Patent Application Publication No. 2004-122020

[The problem the invention is trying to solve]

However, even after the above-mentioned cleaning is continued for a long period of time, the ultrapure water produced by the ultrapure water production device may still not meet the desired manufacturing specifications. For example, when the piping connections in the ultrapure water production device are complicatedly connected, or when the cleanliness of the environment in which the ultrapure water production device is installed is problematic, for example, metal particles and sand with larger particle sizes may be captured by the ultrafiltration membrane device at the front end of the use point and exist in the water treatment system. In this case, the dissolution of components such as metal particles continues for a long time in the water treatment system, resulting in the continuous deterioration of the water quality of the produced ultrapure water.

The present invention is developed to solve the above-mentioned problem, and its purpose is to provide a method for starting up an ultrapure water production device and an ultrapure water production device that can shorten the start-up period of the ultrapure water production device. [Technical means for solving the problem]

The startup method of the ultrapure water production device of the present invention is a startup method of the ultrapure water production device having a water treatment system, the water treatment system at least comprising: a flow path for allowing the treated water to flow through, and an ultrafiltration membrane device arranged on the aforementioned flow path and treating the aforementioned treated water at the front end of the use point. The startup method of the ultrapure water production device comprises: a step of setting a temporary filter device at the front end of the aforementioned ultrafiltration membrane device on the aforementioned flow path, a step of cleaning the aforementioned water treatment system by starting to supply water along the aforementioned flow path after the aforementioned temporary filter device is set, and a step of separating the aforementioned temporary filter device from the aforementioned ultrapure water production device after a predetermined period of time has passed since the start of the aforementioned water supply and cleaning.

The aforementioned cleaning preferably includes a sterilization treatment. Furthermore, it is preferred that after the aforementioned separation process, a water treatment process is performed to start water delivery along the aforementioned flow path until ultrapure water that meets the desired manufacturing specifications is obtained. In addition, it is preferred that the aforementioned ultrapure water manufacturing device further has a storage tank on the upstream side of the aforementioned temporary filtration device on the aforementioned flow path, and the aforementioned flow path has: a circulation pipeline that returns to the aforementioned storage tank after passing through the aforementioned ultrafiltration membrane device, and in the aforementioned cleaning, the aforementioned water is circulated in the aforementioned circulation pipeline. Furthermore, it is preferred that the predetermined period is a period during which the number of cycles calculated based on the amount of water and flow in the circulation pipeline becomes 0.5 to 2200 times as the cleaning begins.

On the other hand, the ultrapure water production device of the present invention comprises: a flow path for allowing the treated water to flow through, an ultrafiltration membrane device arranged on the aforementioned flow path and performing water treatment on the aforementioned treated water at the upstream stage of the use point, and a filter loading and unloading mechanism arranged on the aforementioned flow path at the upstream stage of the aforementioned ultrafiltration membrane device, and the filter loading and unloading mechanism can load and unload the temporary filter device on the aforementioned flow path.

The temporary filter device is preferably, for example, a microfiltration membrane device. In addition, it is preferred that the flow path is constituted by a first pipe, the filter loading and unloading mechanism is provided with a plurality of joints and a first opening and closing valve, the plurality of joints are used to removably connect the second pipe to the first pipe, the second pipe is a branch flow path that branches once from the flow path and converges on the downstream side of the flow path through the temporary filter device, and the first opening and closing valve is arranged on the first pipe between the aforementioned branch position and the aforementioned converging position. It is further preferred that a pair of second opening and closing valves are respectively arranged on the second pipe, for example, before and after the temporary filter device. [Effect of the invention]

According to the present invention, a method for starting up an ultrapure water production device and an ultrapure water production device capable of shortening the start-up period of the ultrapure water production device can be provided.

Hereinafter, the embodiment of the present invention will be described with reference to the drawings. As shown in FIG1 , the ultrapure water production device 10 of the present embodiment is a device for obtaining ultrapure water by subjecting the treated water to water treatment, and the water treatment system 15 thereof comprises: a pre-treatment section 12, a primary pure water production section 14, a flow path 31 of the treated water, a storage tank 16, and a secondary pure water production section 18. The pre-treatment section 12 is for introducing tap water, well water, industrial water, etc. as raw water. The pre-treatment section 12 has an appropriate structure according to the water quality of the raw water, etc., and removes the suspended matter in the raw water to produce pre-treated water. The pre-treatment section 12 is equipped with, for example, a sand filter device, a micro-filter device, etc., and, as required, a heat exchanger for adjusting the temperature of the treated water.

The primary pure water production section 14 removes organic components, ion components, dissolved gases, etc. in the pre-treated water to produce primary pure water, and supplies the primary pure water to the storage tank (TK) 16. The primary pure water production section 14 is composed of, for example, a reverse osmosis membrane device, an ion exchange device (cation exchange device, anion exchange device, mixed bed ion exchange device, etc.), an ultraviolet oxidation device, and a degassing device (vacuum degassing device, membrane degassing device, etc.) in an appropriate combination. The primary pure water, for example, has a total organic carbon (TOC: Total Organic Carbon) concentration of 5μgC/L or less and a resistivity of 17MΩ･cm or more. The storage tank 16 stores the primary pure water and supplies a necessary amount of the primary pure water 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 that is ultrapure water, and supplies it to the ultrapure water use place, that is, the point of use (POU: Point Of Use) 20. The flow path 31 is a flow path for the treated water to flow through, and the treated water that has been treated by the treatment unit 12, the primary pure water production unit 14, and the secondary pure water production unit 18 that constitute the water treatment system 15 is sent to the point of use 20. In addition, as shown in Figures 1 and 2, the storage tank 16 is located on the upstream side of the microfiltration membrane device (temporary filtration device) 27 described later on the flow path 31. Furthermore, the flow path 31 has a circulation line 31b that returns to the storage tank 16 after passing through the ultrafiltration membrane device 28 described later. Here, in the example of FIG. 1 and FIG. 2, the circulation line 31b is configured as a route that returns from the position of the use point 20 located at the most downstream through the storage tank 16 and the secondary pure water production unit 18 to the position of the use point 20. In other words, the remaining ultrapure water after passing through the use point 20 is recovered by the storage tank 16 through the circulation line 31b of the flow path 31.

Specifically, as shown in FIG. 2 and FIG. 3 , the secondary pure water production unit 18 is equipped with: a circulation pump (processed 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, a purifier (polisher) 26, a filter loading and unloading mechanism 30, an ultrafiltration membrane (UF: Ultrafiltration Membrane) device 28, and a particle counter 29.

The circulation pump 22 is a water supply pump for supplying the water to be treated (primary pure water) stored in the storage 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°C by the heat exchanger 23.

The ultraviolet oxidizing device 24 irradiates the treated water (primary pure water) whose temperature is adjusted by the heat exchanger 23 with ultraviolet rays, thereby decomposing and removing trace organic matter in the treated water. The ultraviolet oxidizing device 24 has, for example, an ultraviolet lamp, and generates ultraviolet rays with a wavelength of approximately 185 nm. The ultraviolet oxidizing device 24 may also generate ultraviolet rays with a wavelength of approximately 254 nm. When the treated water is irradiated with ultraviolet rays in such an ultraviolet oxidizing device 24, the ultraviolet rays decompose water molecules to generate hydroxyl groups, which oxidize and decompose organic matter in the treated water.

The membrane degassing device 25 is a device that reduces the pressure on the secondary side of the permeable membrane, allowing only the dissolved gas in the treated water flowing through the primary side to pass through the secondary side and remove it. The purifier 26 is a non-regenerative mixed bed ion exchange device, which has a mixed bed ion exchange resin formed by mixing cation exchange resin and anion exchange resin, and is used to adsorb and remove trace cationic and anionic components in the treated water.

The filter installation and removal mechanism (filter installation and removal mechanism) 30, which will be described in detail later, is provided in front of (immediately in front of) the ultrafiltration membrane device 28 on the flow path 31 of the treated water, and can install and remove the microfiltration membrane device 27 on the aforementioned flow path 31. The ultrafiltration membrane device 28 is provided in front of (immediately in front of) the most downstream use point 20 on the flow path 31.

The ultrafiltration membrane device 28 has a plurality of hollow fiber modules, and the water flow rate of each hollow fiber module is ^5m3 /h or more, generally ^10m3 /h or more. The ultrafiltration membrane device 28 disposed on the flow path 31 further treats the treated water after being treated by the purifier 26 (or the microfiltration membrane device 27 when assembled) at the front stage of the use point 20, thereby removing microparticles with a particle size of 50nm or more to obtain ultrapure water (secondary pure water).

Here, the ultrapure water (ultrapure water satisfying the desired water quality conditions) produced by the ultrapure water production device 10 of this embodiment has a particle number of 200 particles/L or less with a particle size of 50nm or more, a total organic carbon concentration of 1μgC/L or less, and a resistivity of 18MΩ･cm or more. The particle counter 29 measures the particle size of the particles in the secondary pure water (ultrapure water) after the water treatment by the ultrafiltration membrane device 28.

Next, the filter installation and removal mechanism 30 and the temporarily placed microfiltration membrane device 27 are described in detail. As shown in FIG. 2 and FIG. 3, the filter installation and removal mechanism 30 has a plurality of joints 36, 37, 41, 42 and an on-off valve (first on-off valve) 33. On the other hand, the pore size of the membrane of the microfiltration membrane (MF: Microfiltration Membrane) device 27 is larger than the pore size of the membrane of the rear ultrafiltration membrane device 28. The pore size of the microfiltration membrane is not particularly limited, and preferably has a filtering accuracy that can separate particles larger than 0.2μm. This is because, in the present invention, the cause of the early start-up is relatively large particles, so a microfiltration membrane with a larger pore size is sufficient. Moreover, such a microfiltration membrane can substantially reduce the number of membranes and reduce the pressure loss, thereby obtaining good water permeability.

As microfiltration membranes, surface filtration type and depth filtration type can be used. The latter deep filtration type microfiltration membrane can ensure a large amount of water flow, thereby reducing the number of membranes used and becoming cheaper, so it is preferred.

Deep filtration type microfiltration membranes are generally used in the front section of ultrapure water production equipment, such as a guard filter or a pre-treatment section of a reverse osmosis membrane installed in a primary pure water production section. However, in the case of using it in a secondary pure water production section as in the present embodiment, because the pore size of the deep filtration type microfiltration membrane is too large, it was previously believed that the removal of fine particles could not be expected. However, the effect shown in the startup is unexpected.

As surface filtration type microfilter membranes, HDC II series, PolyFine II series (all manufactured by Pall Corporation) and the like can be used; as deep filtration type microfilter membranes, Betafine series (manufactured by 3M Japan Co., Ltd.), PROFILE II, NEXIS series, PROFILE UP series (all manufactured by Pall Corporation) and the like can be used.

That is, the microfiltration membrane device 27 can capture metal particles (foreign matter) separated from, for example, piping in the ultrapure water production device 10, and sand mixed into the water treatment system 15 from the installation environment of the ultrapure water production device 10.

The microfiltration membrane device 27 is a temporary guard filter device. The microfiltration membrane device 27 is installed in the ultrapure water production device 10 when the ultrapure water production device 10 is newly started, for example. However, after the startup of the ultrapure water production device is completed, the microfiltration membrane device 27 is removed from the ultrapure water production device 10 through the filter installation and removal mechanism 30.

Here, the flow path 31 of the treated water is constituted by the pipe 31a. In addition, in order to temporarily place the microfiltration membrane device 27, a pipe (second pipe) 32a is prepared to constitute a branch flow path 32, which is once branched from the flow path 31 and converges on the downstream side of the flow path 31 through the microfiltration membrane device 27. That is, the microfiltration membrane device 27 is interposed in the middle of the pipe 32a.

As shown in Fig. 2 and Fig. 3, the connectors 41 and 42 connect the pipe 32a to the pipe 31a in a detachable manner. In addition, the connectors 36 and 37 also connect the pipe 32a to the pipe 31a in a detachable manner. Specifically, the connectors 36 and 37 make the pipe 32a and the on-off valves 34 and 35 removable from the pipe 31a. In this embodiment, as shown in Fig. 3, the main example is to remove the pipe 32a and the temporary microfiltration membrane device 27 from the pipe 31a through the connectors 41 and 42.

The on-off valve 33 is provided between the aforementioned branch position and the aforementioned confluence position on the pipe 31a, and is used to switch the water flow and the blocking (non-water flow) in the pipe 31a. In addition, a pair of on-off valves (second on-off valves) 34 and 35 are provided on the pipe 32a before and after the temporary microfiltration membrane device 27. The on-off valves 34 and 35 are used to switch the water flow and the blocking (non-water flow) in the pipe 32a.

2 , for example, in a state where the microfiltration membrane device 27 is installed, water is fed via a route that branches once from the flow path 31 and converges on the downstream side of the flow path 31 through the branch flow path 32 and the microfiltration membrane device 27, the on-off valve 33 is closed and the on-off valves 34 and 35 are opened. In addition, in a state where the microfiltration membrane device 27 is separated (removed) from the ultrapure water production device 10 as shown in Figure 3, or in a state where the microfiltration membrane device 27 is provided as shown in Figure 2, but water is supplied to the flow path 31 via a route that does not pass through the branch flow path 32 and the microfiltration membrane device 27, the on-off valve 33 is opened and the on-off valves 34 and 35 are closed.

In this case, the area from the joint 36 to the on-off valve 34 and the area from the on-off valve 35 to the joint 37 become dead spaces, and there is a concern that water quality may deteriorate due to water stagnation. Therefore, after removing the temporary microfiltration membrane device 27 together with the pipe 32a, a thinner pipe is installed in place of the separated pipe 32a, so that water flows from the joint 36 to the joint 37 at a small flow rate, thereby preventing water stagnation.

Next, in addition to FIGS. 1 to 3, the method for starting the ultrapure water production device 10 of the present embodiment (ultrapure water production method using the ultrapure water production device 10) will be described with reference to the flow chart shown in FIG. 4. When the ultrapure water production device 10 is started, first, in addition to assembling the purifier 26, the ultrafiltration membrane device 28, the flow path 31 (pipe 31a), etc., a temporary microfiltration membrane device 27 is installed (assembled) on the main body of the ultrapure water production device 10 through the filter mounting and disassembly mechanism 30 as shown in FIGS. 2 and 4 (S1).

After the microfiltration membrane device 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 microfiltration membrane device 27 is installed in this way, water is supplied from, for example, the front section of the pre-treatment section 12 along the branch flow path 32 and the flow path 31 including the circulation pipe 31b, thereby cleaning the water treatment system 15 including the pre-treatment section 12, each device in the primary pure water production section 14, the above-mentioned flow path 31, the purifier 26, the ultrafiltration membrane device 28, etc. as shown in Figures 1, 2, and 4 (S2). At this time, metal particles separated from the pipes in the ultrapure water production device 10, sand mixed in the water treatment system 15, etc. are captured by the microfiltration membrane device 27.

In the above-mentioned cleaning, the water (cleaning water) used for water delivery to the cleaning water treatment system 15 is preferably pure water. In addition, in such cleaning, the cleaning water (cleaning water) passing through the location of the use point 20 at the start of the cleaning is carried out to go around the circulation pipe 31b for at least a predetermined period of time and then return to the location of the above-mentioned use point 20.

As the aforementioned cleaning begins, the number of cycles calculated based on the water volume and flow rate in the circulation pipe 31b is preferably 0.5 to 2200 times, more preferably 1 to 1000 times, and particularly preferably 40 to 500 times. In addition, the water flow time is preferably 0.25 hours to 1000 hours, more preferably 0.5 hours to 720 hours, and particularly preferably 24 hours to 170 hours. Because there are a lot of foreign matter in the front section of the circulation system, even if the number of cycles is 0.5 times, there is still an effect, but the effect becomes greater if it exceeds 1 time.

When the number of cycles and water flow time is small, the microfiltration membrane cannot fully capture foreign matter, and the startup time cannot be shortened. On the other hand, when the number of cycles and water flow time is large, the foreign matter captured by the microfiltration membrane is crushed and flows out to the back section, and the startup time cannot be shortened. The best conditions will vary according to the length, diameter, number of branches, etc. of the pipes to be laid, and appropriate conditions can be selected within the above range to implement cleaning.

Here, the predetermined period may be, for example, one week. In addition, during the cleaning, the devices in the pre-treatment unit 12, the primary pure water production unit 14, and the secondary pure water production unit 18 are in operation. By the above-mentioned cleaning, metal particles such as those separated from the piping in the ultrapure water production device 10 are captured by the microfiltration membrane device 27.

After a predetermined period of time has passed since the start of cleaning (Yes in S3), the microfiltration membrane device 27 that has captured metal particles, etc., is removed (separated) from the ultrapure water production device 10 (S4). Specifically, after the water supply is stopped, the on-off valves 34 and 35 on the pipe 32a (branch flow path 32) are closed. Then, as shown in FIG. 3, the pipe 32a and the temporarily placed microfiltration membrane device 27 are removed through the joints 41 and 42.

After the microfiltration membrane device 27 is removed, the on-off valve 33 is closed, and each device in the pre-treatment unit 12, the primary pure water production unit 14, and the secondary pure water production unit 18 is put into operation, and then water supply along the flow path 31 including the circulation pipeline 31b is started (raw water is supplied to the pre-treatment unit 12), and water treatment using the water treatment system 15 is implemented (S5). Between the removal step (S4) and the step of implementing the water treatment (S5), washing can also be performed without stopping the water supply. In this case, the on-off valve 33 is opened, and the on-off valves 34 and 35 are closed at the same time or afterwards. Then the microfiltration membrane device 27 can be removed. The water treatment is continued until ultrapure water that meets the desired manufacturing specifications as shown in the above example is obtained (the water quality of ultrapure water meets the specifications) (S6). At this time, whether the particle size of the particles in the secondary pure water (ultrapure water) meets the manufacturing specifications is measured by the particle counter 29. Then, when ultrapure water that meets the manufacturing specifications is obtained (Yes in S6), the startup of the ultrapure water manufacturing device 10 is completed (S7).

Here, the startup method of the ultrapure water production device 10 of the present embodiment is to start cleaning in the water treatment system 15 in a state where the microfiltration membrane device 27 is provided in the front section (immediately in front) of the ultrafiltration membrane device 28, and after a predetermined period of time, the microfiltration membrane device 27 that has captured, for example, metal particles, sand, etc., is removed (separated) from the ultrapure water production device 10, and then water treatment is performed, so that the above-mentioned metal particles, sand, etc. can be removed from the water treatment system 15. Therefore, according to the startup method of the ultrapure water production device 10 of the present embodiment, it is possible to avoid the situation that the components such as sand and metal particles that may exist in the water treatment system 15 continue to dissolve, resulting in a state where the water quality of the ultrapure water is reduced. That is, after removing the microfiltration membrane device 27, the water treatment can quickly obtain ultrapure water that meets the desired manufacturing specifications, thereby shortening the startup period of the ultrapure water production device 10.

In any stage of this operation, sterilization operation can be performed in the secondary pure water production section 18 using hydrogen peroxide or the like. In this case, a pipeline (not shown) that bypasses the purifier 26 and/or the ultrafiltration membrane device 28 is used to remove the purifier 26 and/or the ultrafiltration membrane device 28 from the system (water treatment system 15), and hydrogen peroxide is added to the system using a branch valve installed at any part of the secondary pure water production section 18, such as the storage tank 16 or the suction side of the pump 22. Then, a predetermined period of time is circulated. After sufficient sterilization treatment, the hydrogen peroxide solution is discharged from any place. When the hydrogen peroxide in the system disappears, the bypass of the purifier 26 and/or the ultrafiltration membrane device 28 is stopped.

Furthermore, in the startup method of the ultrapure water production device of the present invention, the water treatment system 15 including the purifier 26 can be cleaned without filling the ion exchange resin in the purifier 26 body, and the cleaning operation can be stopped at any stage and the ion exchange resin can be filled in the purifier 26 body.

Furthermore, although the above operation is explained using the circulation pipeline 31b including the use point 20, as shown in FIG5 , the circulation pipeline 31c bypassing the use point 20 can also be used. In this case, the operation is performed so that the use point 20 is included in the circulation pipeline at any stage. In order to further shorten the startup time, it is preferred to select the startup method of the circulation pipeline 31b including the use point 20.

In addition, in order to supplement the water supply of the circulation pump 22, as shown in Fig. 5, a booster pump 43 may be provided between the purifier 26 and the joint 36. Such a booster pump 43 may also be provided additionally in the secondary pure water production unit illustrated in Figs. 2 and 3, and in the secondary pure water production unit illustrated in Fig. 6 described later.

On the other hand, the verification result shows that, regarding the device structure of the ultrapure water production device 10, when the ultrapure water production device without the above-mentioned temporary filtering device (microfiltration membrane device 27) is used and water treatment is performed after washing with washing water, ultrapure water that meets the manufacturing specifications cannot be obtained even if such washing and water treatment are continued for, for example, 4 months. In this case, the hollow fiber type component in the ultrafiltration membrane device 28 captures metal powder, sand, etc., and the captured foreign matter is crushed over time and flows out to the later stage, which causes the water not meeting the manufacturing specifications. Therefore, after all the hollow fiber components in the ultrafiltration membrane device 28 were replaced with new ones, water treatment was performed again, and finally ultrapure water that met the manufacturing specifications was obtained.

Furthermore, it was verified that when an ultrapure water production device having the same device structure as the ultrapure water production device 10 was used and washing with washing water and water treatment were performed in a state where the microfiltration membrane device 27 was installed, ultrapure water that met the production specifications could not be obtained even if such washing and water treatment were continued for, for example, 3 months. In this case, metal powder, sand, etc. of a size that could be seen by the naked eye were captured in the microfiltration membrane device 27, and by removing the microfiltration membrane device 27 and performing water treatment again, ultrapure water that met the production specifications was finally obtained.

In contrast, it has been verified that according to the startup method of the ultrapure water production device 10 of this embodiment, after cleaning with a cleaning solution containing hydrogen peroxide is performed for one week in a state where the microfiltration membrane device 27 is installed, the microfiltration membrane device 27 that has captured metal particles, sand, etc., is removed from the ultrapure water production device 10, and then water treatment is performed, thereby immediately obtaining ultrapure water that meets the manufacturing specifications.

As described above, according to the startup method of the ultrapure water production device 10 of this embodiment (and the ultrapure water production device 10 to which the startup method can be applied), by effectively utilizing the temporary filter device (microfiltration membrane device 27) and the cleaning and water treatment of the filter attachment and removal mechanism 30, it is possible to shorten the startup period of the ultrapure water production device 10. In addition, it is also possible to use the filter attachment and removal mechanism 40 in the ultrapure water production device and the startup method thereof as shown in FIG. 6 instead of the filter attachment and removal mechanism 30 shown in FIG. When the filter attachment and detachment mechanism 40 is used, after closing the on-off valves 34 and 35, the pipe 32 (branch flow path 32a) and the microfiltration membrane device 27 are removed (separated) together with the on-off valves 34 and 35 through the joints 36 and 37. After the temporarily placed microfiltration membrane device 27 is removed from the ultrapure water production device 10 together with the on-off valves 34 and 35 and the pipe 32a, plugs (water stoppers) 38 and 39 are installed at the locations of the joints 36 and 37 where the pipe 32a was originally installed.

The present invention is specifically described above using the embodiments, but the present invention is not limited to the embodiments, and various modifications can be made in the implementation stage without departing from the gist of the invention. For example, a certain component can be deleted from all the components disclosed in the embodiments, and it is also possible to appropriately combine multiple components disclosed in the embodiments.

10: Ultrapure water production device 12: Pretreatment unit 14: Primary pure water production unit 15: Water treatment system 16: Storage tank (TK) 18: Secondary pure water production unit 20: Point of use (POU) 22: Circulation pump 23: Heat exchanger (HEX) 24: Ultraviolet oxidation device (TOC-UV) 25: Membrane degassing device (MDG) 26: Purifier 27: Microfiltration membrane device (MF) 28: Ultrafiltration membrane device (UF) 29: Particle counter 30,40: Filter loading and unloading mechanism 31: Flow path 31a: Piping (1st piping) 31b,31c: Circulation pipeline 32: Branch flow path 32a: Piping (2nd piping) 33: On-off valve (1st on-off valve) 34,35: On-off valve (2nd on-off valve) 36,37,41,42: Connector 38,39: Plug

[FIG. 1] is a block diagram schematically showing the structure of an ultrapure water production device of an embodiment of the present invention. [FIG. 2] is a block diagram showing the structure of a secondary pure water production unit of the ultrapure water production device of FIG. 1. [FIG. 3] is a diagram showing a state after the temporary microfiltration membrane device is separated from the secondary pure water production unit of FIG. 2. [FIG. 4] is a flow chart showing a method for starting the ultrapure water production device of an embodiment of the present invention. [FIG. 5] is a diagram showing an example of a configuration in which a part of the circulation pipeline of the treated water is different from the secondary pure water production unit of FIG. 2. [FIG. 6] is a diagram showing another separation state different from the separation state of the microfiltration membrane device of FIG. 3.

10: Ultrapure water production device

12: Pre-processing department

14: Primary pure water production department

15: Water treatment system

16: Storage tank (TK)

18: Secondary pure water production department

20: Point of Use (POU)

31: Flow path

31b: Circulation pipeline

Claims (11)

A method for starting an ultrapure water production device is a method for starting an ultrapure water production device having a water treatment system, wherein the water treatment system at least comprises: a flow path for allowing treated water to flow through, an ultrafiltration membrane device disposed on the flow path and treating the treated water at the front end of a use point, and a purifier disposed on the flow path and treating the treated water at the front end of the ultrafiltration membrane device. The method for starting an ultrapure water production device comprises: a purifier disposed on the flow path at the rear end of the purifier and at the front end of the ultrafiltration membrane device. A process of installing a temporary filter device as a microfiltration membrane device and a branch flow path, the branch flow path is once branched from the above-mentioned flow path and passes through the above-mentioned temporary filter device and converges at the upstream of the above-mentioned ultrafiltration membrane device and the downstream side of the above-mentioned flow path, a process of cleaning the above-mentioned water treatment system by starting to send pure water along the above-mentioned flow path after installing the above-mentioned temporary filter device, and a process of separating the above-mentioned temporary filter device and the above-mentioned branch flow path from the above-mentioned ultrapure water production device after a predetermined period of time has passed since the start of the above-mentioned pure water sending and cleaning. A method for starting up an ultrapure water production device as described in claim 1, wherein the aforementioned cleaning includes a sterilization treatment. The method for starting up the ultrapure water production device as described in claim 1 further comprises: after the aforementioned separation process, a water treatment process is performed by starting to deliver the aforementioned treated water along the aforementioned flow path until ultrapure water that meets the desired production specifications is obtained. A method for starting an ultrapure water production device as described in any one of claims 1 to 3, wherein the ultrapure water production device is further provided with a storage tank on the upstream side of the temporary filter device on the branch flow path, and the flow path has: a circulation pipeline that returns to the storage tank after passing through the ultrafiltration membrane device, and in the washing process, the pure water of the water supply is circulated in the circulation pipeline. The method for starting up the ultrapure water production device as described in claim 4, wherein the predetermined period is the period during which the number of circulations calculated based on the water volume and flow rate in the circulation pipeline becomes 0.5 to 2200 times as the cleaning begins. A method for starting an ultrapure water production device as described in any one of claims 1 to 3, wherein the temporary filtration device has a filtration accuracy of separating particles larger than 0.2 μm. The method for starting up an ultrapure water production device as described in any one of claims 1 to 3, wherein the ultrafiltration membrane device comprises a plurality of hollow fiber modules, and the water flow rate of each of the hollow fiber modules is greater than 10 m ³ /h. A method for starting up an ultrapure water production device as described in any one of claims 1 to 3, wherein the number of particles with a particle size of 50 nm or more in the ultrapure water meeting the desired production specifications is less than 200 particles/L. An ultrapure water production device comprises: a flow path for allowing treated water to flow through, an ultrafiltration membrane device disposed on the flow path and treating the treated water at the front end of a use point, a purifier disposed on the flow path and treating the treated water at the front end of the ultrafiltration membrane device, and a filter loading and unloading mechanism disposed on the flow path at the rear end of the purifier and at the front end of the ultrafiltration membrane device, the filter loading and unloading mechanism being capable of loading and unloading the flow path as a microfiltration membrane device. The installation and removal of the temporarily placed filter device, the aforementioned flow path is composed of the first pipe, the aforementioned filter installation and removal mechanism is equipped with a plurality of joints and a first opening and closing valve, the aforementioned plurality of joints are used to removably connect the second pipe to the aforementioned first pipe, the second pipe is a branch flow path that branches from the aforementioned flow path once and converges on the downstream side of the aforementioned flow path through the temporarily placed filter device, and the aforementioned first opening and closing valve is set on the aforementioned first pipe between the aforementioned branch position and the aforementioned converging position. The ultrapure water production device as described in claim 9, wherein a second on-off valve is provided on the second pipe before and after the temporary filter device. The ultrapure water production device as described in claim 9 or 10, wherein a storage tank is further provided on the upstream side of the aforementioned temporary filtration device on the aforementioned flow path, and the aforementioned flow path has: a circulation pipeline that returns to the aforementioned storage tank after passing through the aforementioned ultrafiltration membrane device.

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