Ultra-pure water production system

Abstract

To provide an ultrapure water production system that can produce ultrapure water with a high degree of removal of particles, and supply it to the point of use.SOLUTION: An ultrapure water production system for producing ultrapure water with at least an ultrafiltration membrane apparatus 16, wherein the system is provided with (i) a first organic porous ion exchanger 32 located downstream of the ultrafiltration membrane system 16 in an ultrapure water supply line that supplies ultrapure water to a use point, and (ii) a microfiltration membrane apparatus 35 located at a position downstream of the first organic porous ion exchanger 32 in the ultrapure water supply line.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to an ultrapure water production system that can produce ultrapure water with particularly high purity and supply it to the point of use.

Background Art

[0002] In the manufacturing processes of semiconductor devices and liquid crystal devices, ultrapure water is used for various applications such as cleaning. In a general method for producing ultrapure water, raw water such as river water, groundwater, or industrial water is first pretreated by a pretreatment system and then supplied to a primary pure water system to obtain pure water (also referred to as primary pure water). Then, the primary pure water is supplied to a secondary pure water system (also referred to as a subsystem) to further increase the purity, thereby obtaining ultrapure water. The ultrapure water obtained in the secondary pure water system is supplied to its point of use (also referred to as the place of use or POU (point of use)). When supplying ultrapure water to an ultrapure water-using facility such as semiconductor device manufacturing equipment, in particular, the position where the ultrapure water-using facility receives the ultrapure water is called the point of entry (POE). In the following description, when referring to the point of use of ultrapure water, it shall include the point of entry (POE) of ultrapure water.

[0003] The secondary pure water system is configured such that the ultrapure water that has not been supplied to the use point is returned to the inlet side of the secondary pure water system. That is, in the secondary pure water system, the ultrapure water is always circulating, and by circulating, the ultrapure water undergoes further purification treatment. As a specific configuration of the secondary pure water system, for example, an ultraviolet oxidation device (UV), a non-regenerative ion exchange device (CP) (also called a cartridge polisher), a membrane degassing device (MD), and an ultrafiltration membrane device (UF) are connected in this order to the outlet of the tank that receives the primary pure water. A circulation pipe is provided to return the ultrapure water from the outlet side of the ultrafiltration membrane device to the tank, and a supply pipe branched from the circulation pipe is provided to supply the ultrapure water to the use point. In the following description, the ultrapure water production system refers to a system including a secondary pure water system in which the ultrapure water that has not been supplied to the use point always circulates, the secondary pure water system includes at least an ultrafiltration membrane device, and the supply pipe for supplying the ultrapure water to the use point branches downstream of the ultrafiltration membrane device.

[0004] When ultrapure water is used in the manufacturing processes of semiconductor devices and liquid crystal devices, since the fine particles contained in the ultrapure water directly cause a decrease in the manufacturing yield of the devices, it is necessary to strictly control the size (particle diameter) of those fine particles and the number (or concentration) of fine particles contained in the ultrapure water per unit volume. Arranging the ultrafiltration membrane device at the final stage or a position close to it in the secondary pure water system as described above is also for reducing the amount of fine particles in the ultrapure water. However, in recent years, the quality requirements for ultrapure water have become increasingly strict, and it has become necessary to perform a process to further purify the ultrapure water obtained by the secondary pure water system. For example, it has become necessary to remove the components eluted from the ultrafiltration membrane device itself. In addition, as the semiconductor device manufacturing facilities have become larger in scale, etc., the ultrapure water production system has also become larger in scale, and therefore, it has become necessary to supply the ultrapure water in a large flow rate to a distant location, and in some cases, booster pumps (pressure boosting pumps) are provided in the secondary pure water system or in the pipes from the secondary pure water system to the semiconductor device manufacturing facilities. When a booster pump is provided, it is necessary to remove the fine particles generated in the pump from the ultrapure water.

[0005] As an attempt to further purify ultrapure water, Patent Document 1 discloses that when the raw water used for manufacturing ultrapure water contains metal impurities of any one or more elements among boron, arsenic, aluminum, titanium, chromium, iron, copper, zinc, tin, vanadium, gallium, and lead, at least a monolithic organic porous anion exchanger is filled in the treatment path in the secondary pure water system or in the transfer path from the secondary pure water system to the use point of ultrapure water. An ion exchanger filling module is installed.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] The technology described in Patent Document 1 is aimed at removing specific metal impurities contained in raw water, and Patent Document 1 does not describe highly removing fine particles. There is a need for a technology to produce and supply ultrapure water with highly removed fine particles, including fine particles eluted from ultrafiltration membranes and booster pumps.

[0008] An object of the present invention is to provide an ultrapure water production system that can produce ultrapure water with highly removed fine particles and supply it to the use point.

Means for Solving the Problems

[0009] According to one aspect of the present invention, an ultrapure water production system includes a first organic porous ion exchanger provided downstream of an ultrafiltration membrane device and a precision filtration membrane device provided downstream of the first organic porous ion exchanger in an ultrapure water supply line connected to a use point and supplying ultrapure water to the use point.Moreover, the first organic porous ion exchanger is inserted into the inside of the pipe while pressing against the inner wall of the pipe. .

[0010] In another aspect, the ultrapure water production system of the present invention is provided between an ultrafiltration membrane device and a pump provided upstream of the ultrafiltration membrane device in an ultrapure water supply line connected to a use point and supplying ultrapure water to the use point. It has a first organic porous ion exchanger provided at a position, and a microfiltration membrane device provided at a position downstream of the ultrafiltration membrane device in the ultrapure water supply line. Moreover, the first organic porous ion exchanger is inserted into the inside of the pipe while pressing against the inner wall of the pipe. .

Advantages of the Invention

[0011] According to the present invention, it is possible to obtain an ultrapure water production system that can produce ultrapure water with highly removed fine particles and supply it to a use point.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Mode for Carrying Out the Invention

[0013] Next, embodiments of the present invention will be described with reference to the drawings. Before describing the ultrapure water production system according to the present invention, a general ultrapure water production system for producing ultrapure water from primary pure water will be described. The ultrapure water production system shown in FIG. 1 is configured as a general secondary pure water system (subsystem) used for the production of ultrapure water, and includes a tank 11 for storing primary pure water supplied from a primary pure water system (not shown), a heat exchanger (HE) 12, an ultraviolet oxidation device (UV) 13, a non-regenerative ion exchange device (CP) 14, a membrane degassing device (MD) 15, and an ultrafiltration membrane device (UF) 16. The heat exchanger 12, the ultraviolet oxidation device 13, the non-regenerative ion exchange device 14, the membrane degassing device 15, and the ultrafiltration membrane device 16 are connected to the outlet of the tank 11 in this order. The non-regenerative ion exchange device 14 is filled with bead-shaped or granular ion exchange resin. The membrane degassing device 15 may not be provided. A circulation pipe 20 for returning the ultrapure water that has passed through the ultrafiltration membrane device 16 to the tank 11 is connected to the outlet of the ultrafiltration membrane device 16, and a supply pipe (also referred to as distribution) 21 for supplying ultrapure water to the use point of ultrapure water (or the inlet point of ultrapure water in the ultrapure water using facility) branches from the circulation pipe 20. Therefore, the supply pipe 21 branches from the downstream side of the ultrafiltration membrane device 16. In the illustrated example, a plurality of supply pipes 21 branch from the circulation pipe 20. In this ultrapure water production system, the ultrapure water that has not been supplied to the use point is always circulated to the tank 11 on the upstream side of the ultrafiltration membrane device 16.

[0014] The ultrapure water production system based on the present invention adds an ion exchanger composed of an organic porous body, that is, an organic porous ion exchanger, to a general ultrapure water production system as shown in FIG. 1, and further installs a microfiltration membrane device on at least one downstream side of the organic porous ion exchanger, so as to obtain ultrapure water with highly removed fine particles including the fine particles generated in the ultrafiltration membrane device and the booster pump. General ion exchange resins are in the form of beads or granules with a diameter of several millimeters or less, while the organic porous ion exchanger has a skeleton composed of an organic polymer and forms a continuous macroporous structure with continuous bubble-like macropores, and an ion exchange group is introduced into the organic polymer serving as the skeleton. The organic porous ion exchanger is also called a monolithic organic porous ion exchanger or a monolithic ion exchanger. In particular, the organic porous ion exchanger that is an anion exchanger is called a monolithic anion exchanger (AEM: Anion Exchange Monolith), and the organic porous ion exchanger that is a cation exchanger is called a monolithic cation exchanger (CEM: Cation Exchange Monolith). The organic porous ion exchanger can be formed into any shape and size. Since it is a continuous macroporous structure, the organic porous ion exchanger is formed in a sponge-like shape with elasticity, and the water to be treated can pass through its interior, and ion exchange with the water to be treated is performed during the water passing. An example of the manufacturing method of the organic porous ion exchanger, that is, the monolithic organic porous ion exchanger, is described in Patent Document 1.

[0015] Before explaining the ultrapure water production system according to the present invention, an ultrapure water production system configured by adding an organic porous ion exchanger will be described. FIG. 2 is a diagram showing the main part of such an ultrapure water production system. The ultrapure water production system shown here is the ultrapure water production system shown in FIG. 1, in which a monolithic cation exchanger (CEM) 31 and a monolithic anion exchanger (AEM) 32 are arranged in this order with respect to the outlet of the ultrafiltration membrane device 16. FIG. 2 shows the positions where the monolithic cation exchanger 31 and the monolithic anion exchanger 32 are arranged in the ultrapure water production system and the vicinity thereof. In FIGS. 2 to 7, the membrane degassing device 15 provided between the outlet of the non-regenerable ion exchange device 14 and the inlet of the ultrafiltration membrane device 16 in the ultrapure water production system is not drawn. The position where the supply pipe 21 branches from the circulation pipe 20 is downstream of the monolithic anion exchanger 32 which is the downstream ion exchanger. By arranging the monolithic cation exchanger 31 and the monolithic anion exchanger 32 in this way, it becomes possible to remove fine particles generated in the ultrafiltration membrane device 16, for example, fine particles generated from an adhesive or the like used at the joint in the ultrafiltration membrane device 16. When a bead-shaped or granular ion exchange resin is used instead of the monolithic ion exchanger, it is necessary to use a metal mesh or the like to prevent the outflow of the ion exchange resin, and there is a risk of generating fine particles from the mesh. However, when using the monolithic ion exchanger, no mesh or the like is required, so there is no risk of generating fine particles from the mesh. In addition, since the monolithic ion exchanger has a higher adsorption rate of ionic impurities and fine particles than bead-shaped or granular ion exchange resins, the effective volume can be reduced accordingly, and the equipment can be miniaturized.

[0016] In the ultrapure water production system shown in Fig. 2, the order of arrangement of the monolithic cation exchanger 31 and the monolithic anion exchanger 32 may be reversed, or only one of the monolithic ion exchangers may be provided, or a plurality of at least one of the monolithic cation exchanger 31 and the monolithic anion exchanger 32 may be provided. However, in order to efficiently remove fine particles and the like generated in the ultrafiltration membrane device 16, it is desirable to use the monolithic cation exchanger 31 on the upstream side and the monolithic anion exchanger 32 on the downstream side. Monolithic ion exchangers, that is, organic porous ion exchangers, are considered to be able to remove fine particles by electrostatic effects. In particular, the monolithic anion exchanger 32 has excellent fine particle removal performance. In addition, since fine pores are formed on the surface of the monolithic ion exchanger, there is also a possibility that fine particles are removed by being captured in the pores. The positions where the monolithic cation exchanger 31 and the monolithic anion exchanger 32 are provided may be either in the circulation pipe 20 or the supply pipe 21. That is, it is sufficient that a monolithic ion exchanger is installed in the ultrapure water path from the outlet of the ultrafiltration membrane device 16 to the use point of the ultrapure water. For example, in the configuration shown in Fig. 2, the installation position of the monolithic anion exchanger 32 may be the supply pipe 21 instead of the circulation pipe 20. When a booster pump for boosting pressure is provided inside the ultrapure water production system including the circulation pipe 20 or in the supply pipe 21, the installation position of the monolithic ion exchanger is preferably downstream of the booster pump. In the following description, the line that connects from the outlet of the non-regenerative ion exchange device 14 to the use point via the supply pipe 21 and supplies ultrapure water to the use point is called the ultrapure water supply line.

[0017] Figure 3 shows another example of an ultrapure water production system. The ultrapure water production system shown here is different from that shown in Figure 2 in that the monolithic cation exchanger 31 and the monolithic anion exchanger 32 are provided on the inlet side of the ultrafiltration membrane device 16. This configuration is suitable when a booster pump (P) 33 is provided in the upstream stage of the ultrafiltration membrane device 16. In the illustrated example, the monolithic cation exchanger 31 and the monolithic anion exchanger 32 are connected in this order to the outlet of the booster pump 33, and the water that has passed through the monolithic anion exchanger 32 is supplied to the ultrafiltration membrane device 16. In this ultrapure water production system, the ultrapure water circulated through the circulation pipe 20 is returned to the upstream side of the booster pump 33. Impurities such as metal components and fine particles are generated in the booster pump 33, which becomes a load on the ultrafiltration membrane device 16. However, by disposing the monolithic cation exchanger 31 and the monolithic anion exchanger 32 between the booster pump 33 and the ultrafiltration membrane device 16, the inflow of impurities into the ultrafiltration membrane device 16 can be reduced, and the load on the ultrafiltration membrane device 16 can be alleviated. Further, the monolithic ion exchanger has a smaller pressure loss during water flow than one filled with bead-like or granular ion exchange resin, and thus is advantageous when increasing the supply pressure of ultrapure water by the booster pump 35.

[0018] In the ultrapure water production system shown in Figure 3, the order of arrangement of the monolithic cation exchanger 31 and the monolithic anion exchanger 32 may be reversed, or only one of the monolithic ion exchangers may be provided. However, in order to efficiently remove fine particles and the like generated by the booster pump 33 and the like, it is desirable to use the monolithic cation exchanger 31 on the upstream side and the monolithic anion exchanger 32 on the downstream side.

[0019] Figure 4 shows another example of an ultrapure water production system. The ultrapure water production system shown here is different from that shown in Figure 3 in that the monolithic cation exchanger 31 is provided on the inlet side of the ultrafiltration membrane device 16 while the monolithic anion exchanger 32 is provided on the outlet side of the ultrafiltration membrane device 16. Downstream of the monolithic anion exchanger 32, the supply pipe 21 branches off from the circulation pipe 20. This configuration is suitable when a booster pump 33 is provided in the upstream stage of the ultrafiltration membrane device 16. In that case, the monolithic cation exchanger 31 is arranged between the booster pump 33 and the ultrafiltration membrane device 16. In this ultrapure water production system, the ultrapure water circulated through the circulation pipe 20 is returned to the upstream side of the booster pump 33. In the monolithic cation exchanger 31 provided in the upstream stage of the ultrafiltration membrane device 16, the metal impurities generated by the booster pump 33 are mainly removed, and in the monolithic anion exchanger 32 provided in the downstream stage of the ultrafiltration membrane device 16, the fine particles generated by the booster pump 33 and the ultrafiltration membrane device 16 are mainly removed. What is shown in Figure 4 is also advantageous when increasing the supply pressure of ultrapure water because the monolithic ion exchanger has a small pressure loss during water flow. In the ultrapure water production system shown in Figure 4, the monolithic anion exchanger 32 may be provided at any position in the path of the ultrapure water from the outlet of the ultrafiltration membrane device 16 to the use point of the ultrapure water. Also, in the ultrapure water production system shown in Figure 4, the installation positions of the monolithic cation exchanger 31 and the monolithic anion exchanger 32 may be reversed, with the monolithic anion exchanger 32 provided on the inlet side of the ultrafiltration membrane device 16 and the monolithic cation exchanger 31 provided on the outlet side of the ultrafiltration membrane device 16. However, from the viewpoint of fine particle removal, it is preferable that water flows in the order of the monolithic cation exchanger 31, the ultrafiltration membrane device 16, and the monolithic anion exchanger 32.

[0020] The ultrapure water production system according to the present invention is an ultrapure water production system shown in each of FIGS. 2 to 4, in which a microfiltration membrane device is provided on the downstream side of at least one monolithic ion exchanger, that is, an organic porous ion exchanger, so that fine particles that could not be completely removed by the monolithic ion exchanger can be removed, thereby further enhancing the fine particle removal performance. The ultrapure water production system according to an embodiment of the present invention shown in FIG. 5 is an ultrapure water production system shown in FIG. 2, in which a microfiltration membrane device 35 is provided at the outlet of the monolithic anion exchanger 32, and the supply pipe 21 branches off from the circulation pipe 20 on the downstream side of the microfiltration membrane device 35. The ultrapure water production system shown in FIG. 6 is an ultrapure water production system shown in FIG. 2, in which a microfiltration membrane device 35 is provided in the supply pipe 21. The pore size of the microfiltration membrane of the microfiltration membrane device 35 used in the present invention is, for example, 1 nm or more. In the ultrapure water production system according to the present invention, it is preferable that at least one microfiltration membrane device 35 is provided in the ultrapure water path from the outlet of the ultrafiltration membrane device 16 to the use point of ultrapure water on the downstream side of all the monolithic ion exchangers. Here, an example (FIG. 5) in which the microfiltration membrane device 35 is provided in the circulation pipe 20 and an example (FIG. 6) in which the microfiltration membrane device 35 is provided in the supply pipe 21 in the ultrapure water production system shown in FIG. 2 have been described. Similarly, in the ultrapure water production systems shown in FIGS. 3 and 4, the microfiltration membrane device 35 can be provided in the circulation pipe 20 or the supply pipe 21. When a booster pump for boosting pressure is provided in the ultrapure water production system shown in FIGS. 5 and 6, it is preferably provided between the outlet of the non-regenerative ion exchange device 14 and the inlet of the ultrafiltration membrane device 16.

[0021] In the ultrapure water production system shown in FIGS. 2 to 6, for example, when the pipe length of the supply pipe 21 becomes long, in addition to the monolithic ion exchanger provided on the secondary pure water system side including the circulation pipe 20, a monolithic ion exchanger may also be arranged in the supply pipe 21 to remove fine particles generated from each pipe and the like. Since the monolithic ion exchanger arranged in the supply pipe 21 focuses on removing fine particles rather than metal impurities, considering the electrostatic interaction with fine particles, it is preferably a monolithic anion exchanger rather than a monolithic cation exchanger. The ultrapure water production system shown in FIG. 7 is the ultrapure water production system shown in FIG. 5, in which a monolithic anion exchanger 32 is provided in the supply pipe 21. By providing the monolithic anion exchanger 32 in the supply pipe 21, the amount of fine particles in the ultrapure water supplied to the use point connected to the supply pipe 21 can be further reduced.

[0022] Next, a method for installing a monolithic ion exchanger, that is, an organic porous ion exchanger, in the ultrapure water production system will be described. Patent Document 1 discloses filling a monolithic ion exchanger in a cartridge. The cartridge filled with the monolithic ion exchanger is housed inside a housing (referred to as a cartridge housing, a filter housing, a housing column, etc.) connected to a pipe. However, the monolithic ion exchanger can be made of a sponge-like material having elasticity, and in that case, the monolithic ion exchanger can be directly arranged in the pipe by inserting it into the pipe. When the monolithic ion exchanger is directly arranged in the pipe, a cartridge filled with the monolithic ion exchanger and a housing for housing the cartridge are not required, so there is no risk of generation of impurities and fine particles from these, and it becomes possible to obtain ultrapure water with better water quality.

[0023] When directly placing a monolithic ion exchanger inside a pipe, the material of the pipe in which the monolithic ion exchanger is placed is not particularly limited, and those generally used as pipes for ultrapure water can be used, and metallic pipes or non-metallic pipes can be used. From the viewpoint of less elution of metal components, it is preferable to use a non-metallic pipe. Examples of non-metallic pipes include polypropylene (PP) pipes, polyvinyl chloride (PVC) pipes, chlorinated polyvinyl chloride (CPVC) pipes, high-density polyethylene (HDPE) pipes, low-density polyethylene (LDPE) pipes, polyvinylidene fluoride (PVDF) pipes, perfluoroalkoxy alkane (PFA) pipes, polytetrafluoroethylene (PTFE) pipes, and the like. Among them, it is preferable to use a pipe made of a fluororesin with less elution of metal components and high chemical resistance. Since it has excellent pressure resistance, it is particularly preferable to use a polyvinylidene fluoride (PVDF) pipe.

[0024] As a method of attaching a pipe in which a monolithic ion exchanger is arranged to an ultrapure water supply line, there are methods such as welding, adhesion, and flange fastening. From the viewpoint of ease of maintenance, it is preferable to use the method of flange fastening. Also, the material of the O-ring or gasket used for the pipe connection part is not particularly limited, but from the point of less elution of metal components, it is preferable to use an O-ring made of fluororesin or fluororubber. For maintenance, the pipes in which the monolithic ion exchangers are arranged are preferably provided in two or more in parallel as shown in FIGS. 9 and 10 described later.

[0025] The diameter of the pipe used for placing the monolithic ion exchanger inside is preferably set according to the water flow rate to the monolithic ion exchanger, and generally, it is preferably in the range of 15A to 200A in the nominal diameter defined by JIS (Japanese Industrial Standards). When the pipe diameter is smaller than 15A, when providing pipes in which monolithic ion exchangers are installed in parallel, the number of pipes provided in parallel becomes excessively large to obtain the required water flow rate, and the construction cost becomes high.

[0026] FIG. 8 shows an example in which a monolithic ion exchanger is disposed in a pipe. In FIG. 8, at both ends of a linear pipe member 41, flanges 42 for connection to other pipes 43 (or other pipe members 41) with flanges are provided. Inside the pipe member 41 on the left side in the figure, a monolithic cation exchanger 31 is inserted. In a non-pressed state, the monolithic cation exchanger 31 is processed into a cylindrical shape with a size slightly larger than the inner diameter of the pipe member 41, and is disposed inside the pipe member 41 in a state of pressing the inner wall of the pipe member 41 by being pushed into the pipe member 41 from one end of the pipe member 41. Since the monolithic cation exchanger 41 presses the inner wall of the pipe member 41 in the swelling direction, movement of the monolithic cation exchanger 41 due to water flow is suppressed. In order to surely prevent the monolithic cation exchanger 41 from moving due to water flow, a stepped portion may be provided on the inner wall of the pipe member 41 so that the monolithic cation exchanger 41 engages with the stepped portion. Similarly, a monolithic anion exchanger 42 is inserted inside the pipe member 41 on the right side shown in the figure. When replacing the monolithic ion exchanger, the pipe member 41 in which the monolithic ion exchanger is inserted is removed from the other pipe 43, and then the pipe member 41 in which the new monolithic ion exchanger is inserted is attached to the other pipe 43 using the flange 42. Further, in the example shown in FIG. 8, when it is not necessary to provide a monolithic ion exchanger, the space between the pipes 43 on both sides may be connected by a pipe with a flange in which the monolithic ion exchanger is not provided. In the example shown in FIG. 8, one monolithic ion exchanger is disposed for one pipe member 41, but a plurality of monolithic ion exchangers may also be disposed for one pipe member 41. In that case, a plurality of monolithic cation exchangers 31 may be disposed for one pipe member 41, a plurality of monolithic anion exchangers 32 may be disposed, or a combination of the monolithic cation exchanger 31 and the monolithic anion exchanger 32 may be disposed.

[0027] The monolithic ion exchanger can reduce the pressure loss during water flow compared to those filled with bead-like or granular ion exchange resins. However, when it is desired to increase the supply pressure of ultrapure water, for example, it may be necessary to further reduce the differential pressure of water flow in the monolithic ion exchanger. To reduce the differential pressure of water flow in the monolithic ion exchanger, the water path through which water should flow through the monolithic ion exchanger may be branched into a plurality of pipes provided in parallel, and a monolithic ion exchanger may be provided for each branched pipe. Similarly, when it is desired to reduce the differential pressure of water flow in the microfiltration membrane device 35, the water path through which water should flow through the microfiltration membrane device 35 may be branched into a plurality of pipes provided in parallel, and a microfiltration membrane device 35 may be provided for each branched pipe. FIG. 9 shows a microfiltration membrane device 35 provided at the outlet of the ultrafiltration membrane device 16 in the ultrapure water production system shown in FIG. 3. In this ultrapure water production system, two sets of a monolithic cation exchanger 31 and a monolithic anion exchanger 32 connected in series by pipes are provided in parallel, and the water to be supplied to the ultrafiltration membrane device 16 is branched for these, and the water from both monolithic anion exchangers 32 merges and is supplied to the ultrafiltration membrane device 16. Also, two microfiltration membrane devices 35 are provided in parallel, and the water that has passed through the ultrafiltration membrane device 16 is distributed and supplied to the two microfiltration membrane devices 35. The water that has passed through these microfiltration membrane devices 35 merges, and then is supplied to the supply pipe 21. Although not shown in FIG. 9, a pump such as a booster pump is provided upstream of the monolithic cation exchanger 31.

[0028] Figure 10 shows a system for manufacturing ultrapure water shown in Figure 4, in which a microfiltration membrane device 35 is provided on the downstream side of the monolithic anion exchanger 32. Upstream of the ultrafiltration membrane device 16, the pipe branches into two pipes provided in parallel, and a monolithic cation exchanger 31 is provided for each branched pipe so that the water from the upstream side is diverted. The water passing through these two monolithic cation exchangers 31 merges and is supplied to the ultrafiltration membrane device 16. The pipe at the outlet of the ultrafiltration membrane device 16 also branches into two pipes, and a monolithic anion exchanger 32 is provided for each branched pipe. The water passing through the monolithic anion exchanger 32 first merges and then is diverted again into two pipes. A microfiltration membrane device 35 is provided in each of these two pipes. The water passing through the two microfiltration membrane devices 35 merges. Then, a part of the water is supplied to the supply pipe 21, and the rest is returned to the upstream side of the monolithic cation exchanger 31 via the circulation pipe 20. Although not shown in the system shown in Figure 10, a pump such as a booster pump is provided on the upstream side of the monolithic cation exchanger 31. In the system shown in Figure 10, the outlet water of the two monolithic cation exchangers 32 provided in parallel is first merged and then distributed to the two microfiltration membrane devices 35. However, the outlet water of the monolithic cation exchanger 32 may be directly supplied to the subsequent microfiltration membrane device 35 without merging. In that case, two sets of connectors each connecting one microfiltration membrane device 35 to the outlet of one monolithic cation exchanger 32 are prepared and arranged in parallel for use.

[0029] In each of the above-described ultrapure water manufacturing systems, the water passing conditions through the monolithic ion exchanger are not particularly limited. However, the water passing rate expressed in terms of the space velocity (SV) is preferably 20000 h -1 or less, more preferably 10 - 4000 h -1 or less, and particularly preferably 600 - 4000 h -1 or less. Also, the water passing rate expressed in terms of the linear velocity (LV) is preferably 1000 m / h or less, and more preferably 500 m / h or less.

Example

[0030] Hereinafter, the present invention will be described in more detail based on examples.

[0031] (Example 1) The apparatus shown in Fig. 11 was assembled. The apparatus shown in Fig. 11 includes an ultrafiltration membrane device 16, and the outlet water of the ultrafiltration membrane device 16 is discharged as it is through a first path via a valve 51, and a second path passing through a flow meter (FI) 52, a monolithic cation exchanger 31, a monolithic anion exchanger 32, a microfiltration membrane device 35, and a valve 53 in this order and then discharged, and a third path passing through a flow meter 54, a microfiltration membrane device 36, and a valve 55 in this order and then discharged, and is configured to be distributed to three paths. Separately from these, a measurement pipe 60 connected to a particle counter (PC) 66 is provided. As the particle counter 66, UltraChem40 manufactured by Specttris was used. In order to supply the outlet water [A] of the ultrafiltration membrane device 16, the outlet water [B] of the monolithic cation exchanger 31, the outlet water [C] of the monolithic anion exchanger 32, the outlet water [D] of the microfiltration membrane device 35 provided in the second path, and the outlet water [E] of the microfiltration membrane device 36 provided in the third path to the measurement pipe 60 by switching them respectively, valves 61 to 65 are provided in the respective pipes for supplying the outlet waters [A] to [E] to the measurement pipe 61. As the monolithic cation exchanger 31 and the monolithic anion exchanger 32, the monolithic cation exchanger and the monolithic anion exchanger manufactured based on the method described in paragraphs

[0131] to

[0135] (Reference Example 1 of Patent Document 1) of Patent Document 1 were used. The monolithic cation exchanger and the monolithic anion exchanger were both used by fabricating an ion exchange resin cartridge filled with the monolithic ions with a length of 50 mm for a 150A PPG flange pipe and attaching it to the pipe. As the microfiltration membrane devices 35 and 36, those with a pore diameter of 20 nm for the microfiltration membrane were used.

[0032] Ultra-pure water was supplied to the ultrafiltration membrane device 16, and the outlet water [A] of the ultrafiltration membrane device 16 at that time was continuously distributed and flowed at 30 L / min through the first to third paths, respectively. At this time, the space velocity (SV) of water flow to each of the monolithic cation exchanger 31 and the monolithic anion exchanger 32 was 4000 h -1The linear velocity (LV) was 400 m / h. Then, by operating valves 61 to 65, the outlet water [A] of the ultrafiltration membrane device 16, the outlet water [B] of the monolithic cation exchanger 31, the outlet water [C] of the monolithic anion exchanger 32, the outlet water [D] of the microfiltration membrane device 35 provided in the second path, and the outlet water [E] of the microfiltration membrane device 36 provided in the third path were sequentially fed into the measurement pipe 60 in this order. The number of particles with a diameter of 40 nm or more contained in the outlet waters [A] to [E] was continuously measured by the particle counter 66. In the following description, the number of particles refers to the number of particles contained in the outlet water per unit volume. The measurement results of the number of particles are shown in Fig. 12(a). Also, Fig. 12(b) shows the result of obtaining the moving average for 60 minutes of the results shown in Fig. 12(a). As shown in Figs. 12(a) and (b), for the first approximately 6 days from the start of measurement, the number of particles contained in the outlet water [A] of the ultrafiltration membrane device 16 was determined, but events where the number of particles jumped up spike-like frequently occurred. For the next approximately 5 days, the number of particles in the outlet water [B] of the monolithic cation exchanger 31, that is, the water that passed through the ultrafiltration membrane device 16 and the monolithic cation exchanger 31 in this order, was determined. For the outlet water [B], a result that averaged the number of particles in the outlet water [A] was obtained. For the next approximately 7 days, the number of particles in the outlet water [C] of the monolithic anion exchanger 32, that is, the water that passed through the ultrafiltration membrane device 16, the monolithic cation exchanger 31, and the monolithic anion exchanger 32 in this order, was determined. The number of particles at this time was clearly lower than the number of particles in the outlet water [B]. For the next approximately 6 days, the number of particles in the outlet water [D] of the microfiltration membrane device 35 in the second path, that is, the water that passed through the ultrafiltration membrane device 16, the monolithic cation exchanger 31, the monolithic anion exchanger 32, and the microfiltration membrane device 35 in this order, was determined. The outlet water [D] contained almost no particles. For the last approximately 5 days, the number of particles in the outlet water [E] of the microfiltration membrane device 36 in the third path, that is, the water that passed through the ultrafiltration membrane device 16 and the microfiltration membrane device 36 in this order without passing through the organic porous ion exchanger, that is, the monolithic ion exchanger, was determined. The number of particles in the outlet water [E] was also less than that in the outlet water of each monolithic ion exchanger, but was slightly more than the number of particles in the outlet water [D] of the microfiltration membrane device 35 in the second path.

[0033] From the above results, it was found that by sequentially passing the outlet water of the ultrafiltration membrane device 16 through the monolithic cation exchanger 31 and the monolithic anion exchanger 32, the number of fine particles can be reduced, and by further passing water through the microfiltration membrane device 35, the detected fine particle concentration can be reduced to less than 1 particle / mL.

Explanation of Signs

[0034] 11 Primary pure water tank 12 Heat exchanger (HE) 13 Ultraviolet oxidation device (UV) 14 Non-regenerable ion exchange device (CP) 15 Membrane degassing device (MD) 16 Ultrafiltration membrane device (UF) 20 Circulation pipe 21 Supply pipe 31 Monolithic cation exchanger (CEM) 32 Monolithic anion exchanger (AEM) 33 Booster pump (P) 35, 36 Microfiltration membrane device (MF) 34 Pipe member 36 Flange 38 Pipe 40 Particle counter (PC) 42 Total organic carbon concentration meter (TOC)

Claims

1. In an ultrapure water supply line connected to a use point and supplying ultrapure water to the use point, a first organic porous ion exchanger provided at a position downstream of a microfiltration membrane device, and a precision filtration membrane device provided at a position downstream of the first organic porous ion exchanger in the ultrapure water supply line, comprising The first organic porous ion exchanger is inserted into the pipe in a state of pressing against the inner wall of the pipe. An ultrapure water production system.

2. Comprising a second organic porous ion exchanger provided at a position upstream of the first organic porous ion exchanger in the ultrapure water supply line and downstream of the microfiltration membrane device, The first organic porous ion exchanger is an anion exchanger, and the second organic porous ion exchanger is a cation exchanger. The ultrapure water production system according to claim 1.

3. Comprising a third organic porous ion exchanger provided at a position downstream of the precision filtration membrane device in the ultrapure water supply line. The ultrapure water production system according to claim 1 or 2.

4. A pump provided at a position upstream of the microfiltration membrane device in the ultrapure water supply line, and a fourth organic porous ion exchanger provided at a position downstream of the pump and upstream of the microfiltration membrane device in the ultrapure water supply line, comprising. The ultrapure water production system according to any one of claims 1 to 3.

5. In an ultrapure water supply line connected to a use point and supplying ultrapure water to the use point, a first organic porous ion exchanger provided at a position between a microfiltration membrane device and a pump provided at a position upstream of the microfiltration membrane device, and a precision filtration membrane device provided at a position downstream of the microfiltration membrane device in the ultrapure water supply line, comprising The first organic porous ion exchanger is inserted into the pipe in a state of pressing against the inner wall of the pipe. An ultrapure water production system.

6. Comprising a second organic porous ion exchanger provided at a position upstream of the microfiltration membrane device and downstream of the first organic porous ion exchanger in the ultrapure water supply line, The first organic porous ion exchanger is a cation exchanger, and the second organic porous ion exchanger is an anion exchanger. The ultrapure water production system according to claim 5.

7. The ultra-pure water production system according to claim 2 or 6, wherein the second organic porous ion exchanger is inserted into the pipe in a state of pressing against the inner wall of the pipe.

8. The ultra-pure water production system according to any one of claims 1 to 7, wherein the pore diameter of the microfiltration membrane provided in the microfiltration membrane device is 1 nm or more.

9. The ultra-pure water production system according to any one of claims 1 to 8, wherein at the installation position of the microfiltration membrane device, the path of the water to flow through the microfiltration membrane device branches into a plurality of pipes provided in parallel, and the microfiltration membrane device is provided for each of the branched pipes.

10. The ultra-pure water production system according to any one of claims 1 to 9, wherein at the installation position of at least one of the organic porous ion exchangers provided in the ultra-pure water production system, the path of the water to flow through the at least one organic porous ion exchanger branches into a plurality of pipes provided in parallel, and the at least one organic porous ion exchanger is provided for each of the branched pipes.

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