WO2017130454A1

WO2017130454A1 - Ultrapure water production apparatus and method for operating ultrapure water production apparatus

Info

Publication number: WO2017130454A1
Application number: PCT/JP2016/076555
Authority: WO
Inventors: 佐藤　伸
Original assignee: 栗田工業株式会社
Priority date: 2016-01-28
Filing date: 2016-09-09
Publication date: 2017-08-03
Also published as: TWI710529B; JP2017131846A; KR102602540B1; CN108602705A; SG11201806360WA; JP6119886B1; KR20180103964A; TW201726557A

Abstract

An ultrapure water production apparatus 1 is provided with a primary pure water system 2 and a subsystem 3. The primary pure water system 2 comprises a reverse osmosis membrane (RO) device 4 and a regenerating mixed bed-type ion exchange device 5, and after said regenerating mixed bed-type ion exchange device 5, is provided with a boron monitor 6 as a boron concentration-measuring means and an electric deionization device 7. The subsystem 3 comprises a UV oxidation device 9, a non-regenerating mixed bed-type ion exchange device 10, and an ultrafiltration membrane 11. The boron concentration of primary pure water W1 is continuously monitored by the boron monitor 6, and assuming that the product of the boron concentration [B] of the primary pure water W1 and the boron removal rate of the electric deionization device 7 is the boron concentration [B1] of the treated water W2, the boron concentration of water supplied to the subsystem 3 is continuously monitored. With such an ultrapure water production apparatus 1, it is possible to efficiently remove boron and promptly prevent leaking thereof.

Description

Ultrapure water production apparatus and operation method of ultrapure water production apparatus

The present invention relates to an ultrapure water production apparatus for producing ultrapure water used in the electronics industry such as semiconductors and liquid crystals, and an operation method of the ultrapure water production apparatus. In particular, the present invention relates to an ultrapure water production apparatus capable of efficiently removing boron and preventing the leakage and an operation method thereof.

Conventionally, ultrapure water used in the field of electronic industries such as semiconductors is processed raw water with an ultrapure water production system composed of a pretreatment system, a primary pure water system, and a subsystem for processing primary pure water. It is manufactured by.

In this ultrapure water production apparatus, the pretreatment system is composed of agglomeration, pressurized flotation (precipitation), filtration (membrane filtration) apparatus, etc., and removes suspended substances and colloidal substances in raw water. In this process, high molecular organic substances, hydrophobic organic substances and the like can be removed. The primary pure water system basically includes a reverse osmosis (RO) membrane separation device and a regenerative ion exchange device (such as a mixed bed type or a four-bed five-column type), and the RO membrane separation device removes salts. At the same time, ionic and colloidal TOC are removed. In the regenerative ion exchange apparatus, the TOC component is removed by removing salts and adsorbing or exchanging ions with an ion exchange resin.

Furthermore, the subsystem basically includes a low-pressure ultraviolet (UV) oxidizer, a non-regenerative mixed bed ion exchanger and an ultrafiltration (UF) membrane separator, and further increases the purity of primary pure water. Use ultrapure water. In the low-pressure UV oxidizer, TOC is decomposed into an organic acid and further to CO ₂ by 185 nm ultraviolet rays emitted from a low-pressure ultraviolet lamp. The organics and CO ₂ produced by the decomposition are removed by the non-regenerative mixed bed ion exchanger of the subsequent stage. In the UF membrane separation apparatus, the fine particles are removed, and the outflow particles of the ion exchange resin are also removed.

In the subsystem of such a conventional ultrapure water production apparatus, if weak ion components, particularly boron ions, leak from the primary pure water system, they are removed by a non-regenerative mixed-bed ion exchange device. The mixed bed type ion exchange apparatus needs to be exchanged after adsorbing boron ions to some extent. In recent years, the concentration of boron required for ultrapure water has become lower and lower than 0.1ppt, and non-regenerative mixed bed ion exchangers have poor boron removal efficiency at low concentrations. In order to maintain this reliably, it is necessary to replace the non-regenerative mixed bed type ion exchange apparatus at an early stage, and there is a problem in that the replacement frequency is shortened. Therefore, it is conceivable to provide an electrodeionization device in the subsystem as described in Patent Document 1.

Japanese Patent Laid-Open No. 7-8948

However, when an electrodeionization device is provided in the subsystem as described in Patent Document 1, since the subsystem processes high-purity water close to ultrapure water, it is difficult for electricity to flow. Since the electrical resistance for ions increases, current efficiency is poor, and the load applied to the electrodeionization apparatus also increases. In addition, the electrodeionization device cannot increase the supply pressure of the treated water in consideration of its pressure resistance, and the discharge pressure of the treated water is further smaller than the supply pressure. Since the treatment becomes unstable, the water quality cannot be secured, and the water pressure is insufficient to supply ultrapure water to the point of use. Therefore, although a separate supply device such as a booster pump is provided after the electrodeionization device, it is necessary to consider the treatment of the effluent from the booster pump, and the problem is that the size of the subsystem tends to increase. There is a point.

Furthermore, it is necessary to quickly detect a boron leak to the ultrapure water supplied from the subsystem regardless of the configuration of the ultrapure water production apparatus. Since there is no means for measuring on-site, there is a problem that it is difficult to detect.

The present invention has been made in view of the above problems, and an object of the present invention is to provide an ultrapure water production apparatus capable of efficiently removing boron and quickly preventing the leakage. Moreover, an object of this invention is to provide the operating method of this ultrapure water manufacturing apparatus.

In view of the above object, the present invention firstly provides an ultrapure system having a primary pure water system, and a subsystem including an ion exchange device and a UF membrane device for treating primary pure water obtained from the primary pure water system. In the water production apparatus, there is provided an ultrapure water production apparatus comprising a boron concentration measuring means and an electrodeionization apparatus at a stage subsequent to the primary pure water system and before the subsystem (Invention 1).

According to this invention (Invention 1), the boron removal rate of the electrodeionization apparatus with respect to the primary pure water is measured in advance, and the boron concentration of the primary pure water is continuously monitored by the boron concentration measuring means. The boron detection level of a general-purpose boron monitor or the like is 10 ppb, and the reading is 1 ppb level. It can be simulated with the boron concentration of treated water in the deionizer. And since the boron concentration of the ultrapure water treated by the subsystem is smaller than at least the treated water of this electrodeionization device, the boron concentration of the ultrapure water treated by the subsystem is reduced to the treated water of the electrodeionization device. Judging from the boron concentration as a standard, if the boron concentration of primary pure water is stable, continuous operation is continued, and the boron concentration in the treated water (ultra pure water) of the subsystem is appropriately analyzed, and the rate of increase When the value of the ion exchange increases, it is judged that the breakthrough of the ion exchange device of the subsystem is near, and by replacing this, boron can be efficiently removed and boron leakage can be prevented quickly. it can.

In the above invention (Invention 1), the primary pure water system preferably includes a reverse osmosis membrane device and an ion exchange device (Invention 2).

According to this invention (Invention 2), boron can be efficiently removed in the primary pure water system.

In the above inventions (Inventions 1 and 2), the electrodeionization apparatus comprises a cathode and an anode, a cation exchange membrane and an anion exchange membrane disposed between the cathode and anode, and these cation exchange membrane and anion exchange membrane. A desalting chamber and a concentrating chamber that are partitioned by the above-mentioned method, wherein the desalting chamber and the concentrating chamber are filled with an ion exchanger, and the concentrated water passing means for passing the concentrated water through the concentrating chamber; It is preferable to have means for passing raw water through the desalting chamber and taking out deionized water (Invention 3).

According to this invention (Invention 3), the electrodeionization apparatus having such a configuration has a high boron removal rate and can maintain a substantially constant removal rate, so that it was detected by the boron concentration measuring means. The boron concentration multiplied by the boron removal rate of the electrodeionization apparatus can be accurately simulated as the boron concentration of the treated water of the electrodeionization apparatus.

In the above invention (Invention 3), it is preferable that the concentrated water passing means pass the deionized water that has passed through the desalting chamber as concentrated water (Invention 4).

According to this invention (invention 4), the deionized water that has passed through the desalting chamber is passed through the concentrating chamber, so that the ionic components in the concentrating chamber and the desalting chamber are small. Therefore, it is not necessary to replace the ion exchange device of the subsystem for a long period of time.

In the above invention (Invention 4), the concentrated water flow means introduces the concentrated water into the concentration chamber from the side near the deionized water outlet of the demineralization chamber, and at the raw water inlet of the demineralization chamber. It is preferable to flow out from the near side (Invention 5).

According to this invention (invention 5), the electrodeionization device decreases closer to the side closer to the deionized water outlet in the demineralization chamber, and conversely, closer to the deionized water outlet. By supplying deionized water to the concentrating chamber from the side, the ion concentration gap between the desalting chamber and the concentrating chamber can be reduced over the entire area of the desalting chamber and the concentrating chamber, and the boron ion removal rate can be improved. Since it is large, the removal rate of boron can be further increased, so that it is not necessary to replace the ion exchange device of the subsystem for a long period of time.

In addition, the present invention secondly includes a primary pure water system, and a subsystem including an ion exchange device and a UF membrane device for treating primary pure water obtained from the primary pure water system, and the primary pure water system. A method of operating an ultrapure water production apparatus comprising a boron concentration measuring means and an electrodeionization apparatus upstream of the subsystem after the water system, wherein the water to be treated is connected to the primary pure water system and subsystem. When the ultrapure water is produced by passing the water, whether or not the ion exchange device of the subsystem needs to be replaced based on the boron ion removal rate of the electrodeionization device and the boron concentration measured by the boron concentration measuring means. A method for operating an ultrapure water production apparatus is provided (invention 6).

According to this invention (Invention 6), the boron removal rate of the electrodeionization apparatus with respect to the primary pure water is measured in advance, and the boron concentration of the primary pure water is continuously monitored by the boron concentration measuring means. The boron detection level of a general-purpose boron monitor or the like is 10 ppb, and the reading is 1 ppb level. It is possible to determine whether or not the ion exchange device needs to be replaced based on the boron concentration of the treated water of the deionizer and the boron concentration and the boron concentration of the ultrapure water of the subsystem.

In the above invention (Invention 6), the primary pure water system preferably includes a reverse osmosis membrane device and an ion exchange device (Invention 7).

According to this invention (Invention 7), boron can be efficiently removed in the primary pure water system.

In the above inventions (Inventions 6 and 7), the electrodeionization device comprises a cathode and an anode, a cation exchange membrane and an anion exchange membrane disposed between the cathode and anode, and these cation exchange membrane and anion exchange membrane. A desalting chamber and a concentrating chamber that are partitioned by the above-mentioned method, wherein the desalting chamber and the concentrating chamber are filled with an ion exchanger, and the concentrated water passing means for passing the concentrated water through the concentrating chamber; It is preferable to have means for passing raw water through the desalting chamber and taking out deionized water (Invention 8).

According to this invention (invention 8), the deionized water that has passed through the desalting chamber is passed through the concentrating chamber, so that the ionic components in the concentrating chamber and the desalting chamber are small. Therefore, since the boron removal rate can be increased, it is not necessary to replace the ion exchange device of the subsystem for a long period of time.

In the above invention (Invention 8), it is preferable that the concentrated water flow means introduces a part of the treated water that has passed through the desalting chamber as the concentrated water (Invention 9).

According to this invention (invention 9), the deionized water that has passed through the desalting chamber is passed through the concentration chamber, so that the deionized water itself has a small amount of ionic components. Therefore, it is not necessary to replace the ion exchange device of the subsystem for a long period of time.

In the said invention (invention 9), while introducing the said concentrated water from the side near the deionized water taking-out port of the said demineralization chamber of the said concentration chamber, from the side near the raw | natural water inlet of the said demineralization chamber of the said concentration chamber It is preferable to let it flow out (Invention 10).

According to this invention (invention 10), in the electrodeionization apparatus, the ion concentration decreases toward the side closer to the deionized water outlet in the demineralization chamber, and conversely, it is closer to the deionized water outlet. By supplying deionized water to the concentrating chamber from the side, the ion concentration gap between the desalting chamber and the concentrating chamber can be reduced over the entire area of the desalting chamber and the concentrating chamber, and the boron ion removal rate can be improved. Since it is large, the boron removal rate can be further increased, so that it is not necessary to replace the ion exchange device of the subsystem for a long period of time.

According to the present invention, the boron concentration measuring means and the electrodeionization device are provided in the subsequent stage of the primary pure water system, and the boron concentration of the primary pure water is continuously monitored by the boron concentration measuring means. The measured boron concentration multiplied by the boron removal rate of the electrodeionization device is simulated as the boron concentration of the treatment water of the electrodeionization device, and the subsystem is based on the boron concentration of the electrodeionizer treatment water. Compared with the measured boron concentration of the treated secondary pure water (ultra pure water), if the measured value is larger than the predetermined value, replace the ion exchange device of the subsystem to replace the ion of the subsystem. The exchange device can be exchanged efficiently and without causing leakage of boron.

It is a flowchart which shows the ultrapure water manufacturing apparatus which concerns on 1st embodiment of this invention. It is typical sectional drawing which shows the structure of the electrodeionization apparatus used for the ultrapure water manufacturing apparatus which concerns on the same embodiment. It is a systematic diagram which shows the electrodeionization apparatus of FIG. It is a flowchart which shows the ultrapure water manufacturing apparatus which concerns on 2nd embodiment of this invention.

Hereinafter, the ultrapure water production apparatus according to the first embodiment of the present invention will be described with reference to the accompanying drawings.

FIG. 1 is a flow chart showing an ultrapure water production apparatus according to a first embodiment of the present invention. In FIG. 1, an ultrapure water production apparatus 1 includes a primary pure water system 2 and a subsystem 3, The pure water system 2 includes a reverse osmosis membrane (RO) device 4 and a regenerative mixed bed type ion exchange device 5, and a boron as a boron concentration measuring means is disposed at a subsequent stage of the regenerative mixed bed type ion exchange device 5. A monitor 6 and an electrodeionization device 7 are provided, and the electrodeionization device 7 is connected to the subsystem 3 through a nitrogen-sealed subtank 8. The sub-system 3 includes a sub-tank 8, a supply pump P, a UV oxidizer 9, a non-regenerative mixed bed ion exchanger 10, and an ultrafiltration membrane (UF membrane) 11. An ultrafiltration membrane (UF) The membrane) 11 is returned to the sub tank 8 via the use point UP.

In this ultrapure water production apparatus 1, as the boron monitor 6, a general-purpose boron monitor capable of measuring a boron concentration of 10 ppb level and a reading of 1 ppb level can be used, for example, sold by Central Science Co., Ltd., SIEVERS An ultrapure water measuring online boron analyzer can be used.

Further, as the electrodeionization apparatus 7, a device having a configuration as shown in FIGS. 2 and 3 can be suitably used.

In FIG. 2, the electrodeionization apparatus 7 has a plurality of anion exchange membranes 23 and cation exchange membranes 24 alternately arranged between electrodes (anode 21 and cathode 22), and alternates a concentration chamber 25 and a demineralization chamber 26. The desalting chamber 26 is mixed or filled with an ion exchanger (anion exchanger and cation exchanger) made of an ion exchange resin, an ion exchange fiber, a graft exchanger, or the like. . The concentration chamber 25, the anode chamber 27, and the cathode chamber 28 are also filled with an ion exchanger.

The electrodeionization device 7 includes a water passage means (not shown) for passing the primary pure water W1 into the demineralization chamber 26 and taking the treated water W2 through the regenerative mixed bed ion exchange device 5, and the concentration chamber 25. In the present embodiment, the concentrated water W3 is concentrated from the side close to the outlet of the treated water W2 in the desalination chamber 26. In addition to being introduced into the chamber 25, the concentrated water W3 flows into the concentrating chamber 25 from the side near the raw water inlet of the desalting chamber 26, that is, from the direction opposite to the flow direction of the primary pure water W1 in the desalting chamber 26. Concentrated waste water W4 is discharged.

Specifically, as shown in FIG. 3, the ion concentration was reduced by introducing a part of the treated water W2 obtained from the desalting chamber 26 into the concentration chamber 25 and using the treated water W2 as the concentrated water W3. It is preferable to use concentrated water W3.

Further, as the UV oxidizer 9 of the subsystem 3, a UV oxidizer that irradiates UV having a wavelength near 185 nm, which is usually used in an ultrapure water production apparatus, for example, a UV oxidizer using a low-pressure mercury lamp is used. it can.

The operation method of the ultrapure water production apparatus having the above-described configuration will be described. First, treated water W that has been pretreated by a pretreatment means (not shown) is supplied to the primary pure water system 2 as necessary, and the reverse osmosis membrane (RO) device 4 and the regenerative mixed bed ion exchange device 5 To process. The reverse osmosis membrane (RO) device 4 removes ionic and colloidal TOC in addition to removing salts. In the regenerative type mixed bed type ion exchange device 5, in addition to removing salts, the TOC component adsorbed or ion exchanged by the ion exchange resin is removed to produce the primary pure water W1.

In the present embodiment, the boron concentration [B] of the primary pure water W1 of the regenerative mixed bed ion exchanger 5 is continuously monitored by the boron monitor 6 having a boron detection level of 10 ppb and a reading value of 1 ppb. And after processing this primary pure water W1 with the electrodeionization apparatus 7, the obtained treated water W2 is supplied to the sub tank 8. FIG.

At this time, the boron removal rate is calculated in advance by measuring the boron concentration in the treated water W2 of the electrodeionization apparatus 7 when the predetermined primary pure water W1 having a known boron concentration is treated. The boron removal rate of the electrodeionization apparatus 7 is preferably 99% or more, particularly preferably 99.99% or more. In particular, the above-described electrodeionization apparatus as shown in FIGS. 2 and 3 is suitable for setting the boron removal rate to 99.99% or more. The product of the boron concentration of the primary pure water W1 and the boron removal rate of the electrodeionization apparatus 7 can be simulated with the boron concentration [B1] of the treated water W2 (for example, the boron concentration [B of the primary pure water W1 [B ] Is 1 ppb or less and the boron removal rate of the electrodeionization apparatus 7 is 99.99%, the boron concentration [B1] of the treated water W2 can be assumed to be 0.1 ppt or less). Thus, even if the boron concentration of the treated water W2 supplied to the subsystem 3 is 1 ppb or less, it can be continuously monitored.

Subsequently, the treated water W2 supplied to the sub tank 8 is supplied by the pump P and processed. In the subsystem 3, processing is performed by the UV oxidation device 9, the non-regenerative mixed bed ion exchange device 10, and the ultrafiltration membrane 11. In the UV oxidizer 9, TOC is decomposed to an organic acid or CO ₂ level by ultraviolet rays having a wavelength of 185 nm emitted from a UV lamp. Decomposed organic acids and CO ₂ is removed in non-regenerative mixed bed ion exchange device 10 in the subsequent stage. In the ultrafiltration membrane 11, fine particles are removed, and the outflow particles of the non-regenerative mixed bed ion exchanger 10 are also removed, and secondary pure water (ultra pure water) W5 is obtained. After this secondary pure water W5 is supplied to the use point UP, the unused portion is returned to the sub tank 8.

In such operation of the ultrapure water production apparatus 1, the boron concentration of the secondary pure water (ultra pure water) W5, which is the treated water of the subsystem 3, is usually much larger than the boron concentration [B1] of the treated water W2. Therefore, if the boron concentration [B1] of the treated water W2 of the electrodeionization apparatus 7 is at a level below the required water quality in consideration of the reduction in the subsystem 3, the water quality is “no problem”. As long as it is continuously operated. For example, if the required water quality of boron in the secondary pure water W5 is 0.1 ppt, the boron removal rate of the electrodeionization apparatus 7 is 99, 99%, and the subsystem 3 can reduce it to 1/10 or less, the primary If the boron concentration of the pure water W1 is 10 ppb or less, continuous operation can be performed.

Further, since the boron removal ability of the non-regenerative mixed bed ion exchange apparatus 10 is reduced by long-term use and boron easily leaks into the secondary pure water W5, the precise analysis of the secondary pure water W5 is periodically performed. To actually measure the actual boron concentration of the secondary pure water W5. Then, by comparing the actual measured value [B2] of the boron concentration with the boron concentration [B1] of the treated water W2, the measured value [B2] of the boron concentration is a decrease rate with respect to the boron concentration [B1] of the treated water W2. If it shows a tendency to decrease, it is preferable to replace the non-regenerative mixed bed ion exchange apparatus 10 even before the boron concentration [B2] exceeds 0.1 ppt. In this way, boron leakage to the secondary pure water W5 can be prevented in advance. In addition, since the performance of the non-regenerative mixed bed ion exchange device 10 actually shows a tendency to deteriorate, the non-regenerative mixed bed ion exchange device 10 is replaced, so that the replacement frequency can be reduced. So it is also economical.

In particular, in the present embodiment, as the electrodeionization apparatus 7, a part of the treated water W2 is concentrated water W3, and the counter flow is transiently passed through the concentration chamber 25 in the direction opposite to the water flow direction of the demineralization chamber 26. Since the concentrated drainage W4 is discharged from the concentration chamber 25 through the system, the concentration of ions in the concentrated water W3 in the concentration chamber 25 becomes lower on the extraction side of the desalination chamber 26, and desalination due to concentration diffusion. Since the influence on the chamber 26 is reduced, the boron removal rate is improved. Moreover, since the water supply of the electrodeionization apparatus 7 is the primary pure water W1, since there are few ions (for example, electrical resistance is as large as about 18 MΩ * cm), a large amount of current is required, but the desalination chamber 26 and the concentration are concentrated. By filling both chambers 25 with ion exchangers, the electrical resistance in the desalting chamber 26 and the concentrating chamber 25 can be reduced, so that the operating cost can be reduced.

Furthermore, in this embodiment, since the nitrogen tank sealed as the sub tank 8 is used, dissolution of carbon dioxide and oxygen in the air can be suppressed and a decrease in specific resistance of the secondary pure water W5 can be suppressed. It is like that.

Next, the ultrapure water production apparatus according to the second embodiment of the present invention will be described with reference to FIG.

The ultrapure water production apparatus of the second embodiment includes the primary pure water system 2 and the subsystem 3 in the first embodiment described above, and the subsystem 3 includes the UV oxidation apparatus 9 and the anion exchange resin apparatus 12. And a degassing membrane 13, a non-regenerative mixed bed ion exchange device 10, and an ultrafiltration membrane (UF membrane) 11.

By providing the anion exchange resin device 12 and the degassing membrane 13 in the subsystem in this manner, the electrodeionization device 7 itself does not have airtightness, so that a small amount of carbon dioxide or oxygen is mixed in the primary pure water W1. Although there is a risk, since the CO ₂ is removed by the anion exchange resin device 12 and the remaining gas component such as dissolved oxygen can be removed by the degassing membrane 13, the dissolved gas component can be reduced.

As mentioned above, although this invention has been demonstrated based on the said embodiment, this invention is not restricted to the said embodiment, A various deformation | transformation implementation is possible, and the primary pure water system 2 and the subsystem 3 are the structure of a present Example. Not limited to various configurations. For example, in the primary pure water system 2, the reverse osmosis membrane (RO) device 4 may be arranged in two stages. In the first embodiment, the UV oxidizer 9 is provided in the subsystem 3, but the UV oxidizer 9 may not be provided in some cases. Further, although the nitrogen-sealed one is used as the sub-tank 8, it may be a normal sub-tank, and the sub-tank 8 may not be used in some cases. Further, other water quality analysis means such as a specific resistance meter is provided for measuring the quality of the secondary pure water W5, and the water quality of the secondary pure water W5 is measured on-site, and the specific resistance is lower than a predetermined set value. If it falls, you may make it replace | exchange the non-regenerative type mixed bed type ion exchange apparatus 10. FIG.

Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples, but the present invention is not limited to the following examples.

[Example 1]
Municipal water (treated water) W in Yoshida-cho, Sugawara-gun, Shizuoka Prefecture was treated with a primary pure water system 2 comprising a reverse osmosis membrane (RO) device 4 and a regenerative mixed bed ion exchange device 5. While measuring the boron concentration of this primary pure water W1 with the boron monitor 6, it processed with the electrodeionization apparatus 7, and the treated water W2 was stored in the sub tank 8. FIG. The treated water W2 in the sub tank 8 is provided with a UV oxidation device 9, an anion exchange resin device 12, a degassing membrane 13, a non-regenerative mixed bed ion exchange device 10 and an ultrafiltration membrane (UF membrane) 11 in this order. The secondary pure water W5 was produced by passing water through the subsystem 3.

In addition, as the electrodeionization apparatus 7, the following were used.
Electrodeionization equipment: Kurita Kogyo Co., Ltd. KCDI-UPz, desalination chamber 26, concentration chamber 25 and

electrode chambers

27 and 28 are filled with ion exchange resin, and a part of treated water W2 is concentrated in a countercurrent manner. 25, water flow, boron removal rate 99.99% or more

In the operation of this ultrapure water production apparatus, the value of the boron monitor 6 was stable at 1 to 5 ppb, and the boron concentration of the treated water W2 was estimated to be 0.1 ppt or less, so that the continuous operation was performed. The boron concentration of the treated water W2 was analyzed finely once a month, but was stable at a boron concentration of 0.1 ppt or less, and the boron concentration of the secondary pure water W5 was also 0.1 ppt or less. The specific resistance value of the secondary pure water W5 is stable at an ultrapure water level of approximately 18.2 MΩ · cm even after 3 years, and the non-regenerative mixed bed ion exchange of the subsystem 3 for 3 years. Replacement of the device 10 was not necessary.

[Comparative Example 1]
In Example 1, without using the electrodeionization apparatus 7, the boron monitor 6 was provided in the subsequent stage of the non-regenerative mixed bed ion exchange apparatus 10 for monitoring.

In the operation of this ultrapure water production apparatus, since the value of the boron monitor 6 exceeded 1 ppb in 3 weeks, it was necessary to replace the non-regenerative mixed bed ion exchange apparatus 10.

[Comparative Example 2]
In Example 1, the boron monitor 6 was provided after the non-regenerative mixed bed ion exchange apparatus 10 of the subsystem 3 for monitoring, but the boron concentration could not be detected and the non-regenerative mixed bed type was not detected. It was difficult to determine the replacement time due to breakthrough of the ion exchanger 10.

[Comparative Example 3]
In Example 1, monitoring by the boron monitor 6 is performed in the same manner except that the electrodeionization device 7 is not used in the primary pure water device 2 but the electrodeionization device is arranged at the subsequent stage of the UV oxidation device 9 of the subsystem 3. went.

In the operation of the ultrapure water production apparatus as described above, the value of the boron monitor 6 was stable at 1 to 5 ppb. However, the boron concentration of the inflow water of the subsystem 3 is large and the boron monitor 6 is provided in the subsystem 3. Since the water pressure of the treated water in the electrodeionization device is low and unstable, the treatment in the anion exchange resin device 12 and the like provided in the subsequent stage is not stable, and therefore, a precise analysis of the secondary pure water W5 once a month is performed. The fluctuation of the boron concentration in the gas was large, and it was difficult to judge the replacement time due to breakthrough of the non-regenerative mixed bed ion exchanger 10. In addition, a decrease in the performance of the electrodeionization apparatus, which is considered to be an influence of the oxidizing substance generated in the UV oxidation apparatus 9, was also observed.

DESCRIPTION OF SYMBOLS 1 ... Ultrapure water production apparatus 2 ... Primary pure water system 3 ... Subsystem 4 ... Reverse osmosis membrane (RO) apparatus 5 ... Regenerative mixed bed type ion exchange apparatus 6 ... Boron monitor (boron concentration measuring means)
DESCRIPTION OF SYMBOLS 7 ... Electrodeionization apparatus 8 ... Sub tank 9 ... UV oxidation apparatus 10 ... Non-regenerative mixed bed type ion exchange apparatus 11 ... Ultrafiltration membrane (UF membrane)
DESCRIPTION OF SYMBOLS 12 ... Anion exchange resin apparatus 13 ... Deaeration membrane W ... To-be-processed water W1 Primary pure water W2 ... Treated water W3 ... Concentrated water W4 ... Concentrated waste water W5 ... Secondary pure water (ultra pure water)

Claims

In the ultrapure water production apparatus having a primary pure water system, and a sub-system provided with an ion exchange device and a UF membrane device for treating the primary pure water obtained from the primary pure water system, the latter stage of the primary pure water system An ultrapure water production apparatus comprising a boron concentration measuring means and an electrodeionization device in the preceding stage of the subsystem.
The ultrapure water production apparatus according to claim 1, wherein the primary pure water system includes a reverse osmosis membrane device and an ion exchange device.
The electrodeionization apparatus comprises a cathode and an anode, a cation exchange membrane and an anion exchange membrane disposed between the cathode and the anode, and a desalting chamber and a concentration chamber formed by the cation exchange membrane and the anion exchange membrane. The demineralization chamber and the concentration chamber are filled with an ion exchanger, and the concentrated water passage means for passing the concentrated water to the concentration chamber and the raw water to the demineralization chamber are dewatered. The ultrapure water production apparatus according to claim 1, further comprising means for taking out ionic water.
The ultrapure water production apparatus according to claim 3, wherein the concentrated water flow means passes deionized water that has passed through the demineralization chamber as concentrated water.
The concentrated water flow means introduces the concentrated water into the concentration chamber from the side near the deionized water outlet of the desalting chamber and flows out from the side near the raw water inlet of the desalting chamber. The ultrapure water production apparatus according to claim 4.
A primary pure water system; and a subsystem including an ion exchange device and a UF membrane device for treating the primary pure water obtained from the primary pure water system; A method for operating an ultrapure water production apparatus comprising a boron concentration measuring means and an electrodeionization device in the previous stage, wherein the treated water is continuously passed through a primary pure water system and a subsystem to obtain ultrapure water. In manufacturing, the necessity of replacement of the ion exchange device of the subsystem is judged from the boron ion removal rate of the electrodeionization device and the boron concentration measured by the boron concentration measuring means. Operation method of pure water production equipment.
The operation method of the ultrapure water production apparatus according to claim 6, wherein the primary pure water system has a reverse osmosis membrane device and an ion exchange device.
The electrodeionization apparatus comprises a cathode and an anode, a cation exchange membrane and an anion exchange membrane disposed between the cathode and the anode, and a desalting chamber and a concentration chamber formed by the cation exchange membrane and the anion exchange membrane. The demineralization chamber and the concentration chamber are filled with an ion exchanger, and the concentrated water passage means for passing the concentrated water to the concentration chamber and the raw water to the demineralization chamber are dewatered. The operation method of the ultrapure water production apparatus according to claim 6, further comprising means for taking out ionic water.
The operation method of the ultrapure water production apparatus according to claim 8, wherein the concentrated water flow means introduces a part of the treated water that has passed through the desalination chamber as the concentrated water.
The concentrated water is introduced from a side near the deionized water outlet of the demineralizing chamber of the concentrating chamber, and flows out from a side of the concentrating chamber near the raw water inlet. The operating method of the ultrapure water manufacturing apparatus of Claim 9.