JP7257824B2 - Particle removal membrane device, ultrapure water production device, and ultrapure water production method - Google Patents

Description

The present invention relates to a particle removal membrane device that removes particles in a liquid by a particle removal membrane such as an ultrafiltration membrane used in the production of ultrapure water, and an ultrapure water production apparatus using the particle removal membrane device. and a manufacturing method.

The ultrapure water production equipment that produces ultrapure water to be supplied to the point of use, for example, is composed of a combination of devices such as an ultraviolet oxidation device, a non-regenerative ion exchange device, and a deaeration device. A fine particle removing membrane device having a membrane for removing fine particles in water is provided at the end on the point side. The membrane provided in the particle removal membrane apparatus for removing particles is an ultrafiltration membrane (UF membrane), a microfiltration membrane (MF membrane), or the like, and an ultrafiltration membrane is usually used. Ultrapure water production equipment is required to be able to supply high-quality ultrapure water to points of use in a short period of time.

By the way, in the ultrapure water production equipment, the inside of the equipment is cleaned in order to remove impurities that have adhered and accumulated inside the equipment for various reasons, and to suppress the growth of viable bacteria in the equipment. or sterilized. For example, Patent Document 1 discloses that two microparticle removal membrane devices are provided in parallel in an ultrapure water production system, and that when the entire ultrapure water production device is sterilized, the two microparticle removal membrane devices are flowed in series. Disclosed is the flow of the sterilizing liquid after switching the path, the flow of the sterilizing liquid to one of the microparticle removal membrane devices while exchanging the membrane inside the other microparticle removal membrane device, and the like. In Patent Document 2, after the inside of the ultrapure water production apparatus is washed with an alkaline solution, a cleaning and sterilization step of sterilizing with a sterilizing solution is performed twice or more, so that after the cleaning and sterilization process, the ultrapure water production apparatus It is disclosed to shorten the start-up period until the ultrapure water that satisfies the required water quality can be obtained. Patent Document 3 discloses that in an ultrapure water production apparatus in which a first particle removal membrane device and a second particle removal membrane device are provided in parallel, as the second particle removal membrane device, regardless of the operating state of the system, By using a device capable of cleaning and sterilizing and inserting, flushing, and removing membranes, the time from the end of cleaning and sterilization of the entire ultrapure water production equipment to the start of supplying high-quality ultrapure water disclosed to be shortened.

WO2015/012248 WO2008/123351 JP 2014-217830 A

The techniques disclosed in Patent Documents 1 to 3 relate to cleaning and sterilization of the entire ultrapure water production apparatus. During the subsequent period until the water quality rises, ultrapure water cannot be supplied to the point of use. In particular, in the technique disclosed in Patent Document 3, the second particle removal membrane device must be capable of processing at a large flow rate equivalent to that of the first particle removal membrane device. The overall size of the membrane device increases, which is disadvantageous in terms of installation space and increases cost.

On the other hand, the particle removal membrane device, which is installed at the end of the use point side and has the property of removing fine particles, is a device that requires reliable cleaning and sterilization among the devices that make up the ultrapure water production system. . Therefore, there is a demand to be able to clean and sterilize the particle removal membrane device without interrupting the supply of ultrapure water to the point of use.

An object of the present invention is to remove fine particles that can perform at least one of cleaning and sterilization of ultrapure water without interrupting the supply of ultrapure water to the point of use even when the amount of treated water in the ultrapure water production system is large. An object of the present invention is to provide a membrane device, and an ultrapure water production apparatus and an ultrapure water production method using such a particulate removal membrane device.

The particle removal membrane device of the present invention is a particle removal membrane device having a plurality of modules including at least a plurality of membrane modules provided with particle removal membranes, wherein at least a portion of the plurality of membrane modules are installed in parallel with each other. At least one of the membrane modules installed in parallel is defined as a first membrane module, and a membrane module different from the first membrane module is defined as a second membrane module. A flow path that allows water to flow separately from the second membrane module, a switching means for switching the flow path, and a first pipe and a second pipe that are provided in common to the membrane modules arranged in parallel. and a third pipe, wherein the switching means is installed in parallel with the first on-off valve provided between the inlet of each membrane module installed in parallel and the first pipe a second on-off valve provided between each outlet of the membrane module and the second pipe; At least one of replacement of the first membrane module and passage of the chemical solution to the first membrane module can be executed while water is being passed through the module to remove fine particles, and the particulate removal membrane device is configured to: For each membrane module, a first branch pipe connected to the pipe between the first on-off valve corresponding to the one membrane module and the inlet of the first membrane module; a second branch pipe connected to the pipe between the provided third on-off valve, the second on-off valve corresponding to the first membrane module, and the outlet of the first membrane module; and a fourth on-off valve provided in the branch pipe of the first membrane module, and the outlet of the first membrane module is the outlet of the water that has permeated the fine particle removal membrane provided in the first membrane module. wherein the first membrane module further comprises a concentrated water outlet which is an outlet for water that has not permeated the fine particle removal membrane provided in the first membrane module, and the switching means is the membranes installed in parallel A fifth on-off valve is provided for each module, and the fifth on-off valve is provided between the concentrated water outlet of each of the membrane modules installed in parallel and the third pipe. is, for each first membrane module, a third branch pipe connected to the pipe between the fifth on-off valve corresponding to the first membrane module and the concentrated water outlet of the first membrane module; a sixth on-off valve provided in the third branch pipe, and supplying water to at least one membrane module to remove fine particles contained in the water.

The ultrapure water production apparatus of the present invention is characterized in that the ultrapure water production apparatus for producing ultrapure water has the particle removal membrane device of the present invention at the position of the end from which the produced ultrapure water is discharged. .

The ultrapure water production method of the present invention is a method of producing pure water using the ultrapure water production apparatus of the present invention, wherein the switching means switches the first membrane module from the water flow line including the second membrane module. After disconnecting, a chemical solution is supplied to the first module to perform at least one of cleaning and sterilization of the first membrane module.

According to the present invention, even when the amount of treated water in the ultrapure water production system is large, the fine particle removal membrane device provided in the ultrapure water production system without interrupting the supply of ultrapure water to the point of use. at least one of cleaning and sterilization of

1 is a flow sheet showing an example of the configuration of an ultrapure water production apparatus; 1 is a flow sheet showing a fine particle removal membrane device according to an embodiment of the present invention; FIG. 2 illustrates sterilization, cleaning and rinsing in the apparatus shown in FIG. 1; FIG. 2 is a diagram illustrating replacement of a membrane module in the apparatus shown in FIG. 1; 4 is a flow sheet showing a fine particle removal membrane device according to another embodiment of the present invention. FIG. 6 is a diagram for explaining exchange and rinsing of a membrane module in the apparatus shown in FIG. 5;

Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows an example of the configuration of an ultrapure water production system incorporating a particulate removal membrane device according to the present invention.

This ultrapure water production apparatus is configured as a subsystem for supplying primary pure water to produce ultrapure water, and includes a tank 11 for temporarily storing the primary pure water. A pump 12 for feeding the pure water in the tank 11 is provided at the outlet of the tank 11, and the outlet of the pump 12 is provided with a heat exchanger (HE) 13, an ultraviolet oxidation device (UV) 14, a non-regenerative type An ion exchange device (CP; cartridge polisher) 15, a degassing device (MD) 16, and a particle removal membrane device (UF) 19 are connected in series in this order. The pure water in the tank 11 is purified while passing through the heat exchanger 13, the ultraviolet oxidation device, the non-regenerative ion exchange device 15, the degassing device 16, and the fine particle removal membrane device 19, and the fine particles are removed as ultrapure water. It is supplied to the point of use from the outlet of the removal membrane device 19 . Therefore, the fine particle removal membrane device 19 is provided at the end of the ultrapure water production apparatus where the produced ultrapure water is discharged. The ultrapure water that has flowed out of the particle removal membrane device 19 but has not been supplied to the point of use is returned to the tank 11 via the circulation pipe 50 . In this ultrapure water production apparatus, by circulating the pure water through the circulation pipe 50, the pure water is repeatedly purified, and the ultrapure water of better quality can be supplied to the point of use. can.

A membrane deaerator is preferably used as the deaerator 16 . A flow control valve 17 is provided in the pipe between the outlet of the pump 12 and the inlet of the heat exchanger 13 . A pressure gauge (PI) 18 is provided at the exit of the particle removal membrane device 19 to measure the pressure of the ultrapure water supplied to the point of use. The pump 12 is driven and controlled by a drive circuit (not shown), and the supply pressure to the point of use is controlled by at least one of control of the flow rate or discharge pressure of the pump 12 by the drive circuit and adjustment of the flow control valve 17. Alternatively, the amount of water supplied can be adjusted. Here, the flow control valve 17 is provided outside the particle removal membrane device 19, but if a valve having a flow control function is provided inside the particle removal membrane device 19, the flow control valve 17 is not provided. may

Next, the configuration of the particle removal membrane device 19 in the ultrapure water production system shown in FIG. 1 will be described. In FIGS. 2 to 6, which are referred to in the following description, valves in the open state are represented by white valve symbols, and valves in the closed state are represented by black valve symbols. Also, the circled letter B indicates that it is connected to a bypass line (not shown) used for recovering, discharging or blowing the unnecessary liquid, and the circled letter C indicates that it is connected to a sterilizing liquid or It shows that it is connected to a chemical solution injection line for introducing a cleaning solution. 2 to 4 show an example of the configuration of the particulate removal membrane device according to one embodiment of the present invention. FIG. 2 shows the particulate removal membrane device in a normal operating state, and FIG. 3 shows the configuration of the membrane module. FIG. 4 shows the time when sterilization, washing, and rinsing are performed, and the time when the membrane module is replaced.

The particle removal membrane device can have a plurality of membrane modules each having a membrane that removes particles, and can have pipes and valves for switching the flow of water to the plurality of membrane modules. It is. The membrane module is constructed so that it can be attached to or detached from the particulate removal membrane device as required. The particle removal membrane provided inside the membrane module to remove particles is, for example, an ultrafiltration membrane. Here, since water is supplied to the membrane based on the cross-flow method, each membrane module has an inlet to which the water to be treated is supplied and a concentration unit to discharge the water that has not passed through the fine particle removal membrane, that is, the concentrated water. It has a water outlet and a permeated water outlet for discharging the water that has permeated the fine particle removal membrane, that is, the permeated water. As used herein, the water that has passed through the membrane module means water that has passed through the fine particle removal membrane provided in the membrane module. As each membrane module has an inlet, a concentrate outlet, and a permeate outlet, the particulate removal membrane device also has an inlet, a concentrate outlet, and a permeate outlet. However, the membrane module is not limited to the cross-flow type, and may be of the dead end filtration type which does not have an outlet on the concentration side. The membrane module preferably used in the present embodiment is of a cross-flow type having an ultrafiltration membrane composed of hollow fibers in a housing. Although the illustrated particle removal membrane device can have up to four membrane modules installed simultaneously, the number of membrane modules that can be installed simultaneously in the particle removal membrane device is not limited to four.

In the particulate removal membrane device, a portion composed of piping and valves corresponding to individual membrane modules is called a water flow line. Since the fine particle removal membrane apparatus shown in FIG. 2 can be attached with a maximum of four membrane modules, four systems of water flow lines, that is, lines a to d are provided. In the state shown in FIG. 2, membrane modules 20a to 20c are attached to lines a to c, respectively, and a total of three membrane modules 20a to 20c are provided in parallel with each other. Line d is vacant, but dummy module 40d is detachably attached. The dummy module 40d has the same shape and dimensions as the membrane modules 20a to 20c, but differs from the membrane modules 20a to 20c in that it does not have a particle removal membrane or the like inside. Although it is possible not to install the dummy module 40d, the inside of the piping for installing the membrane module in the line d is exposed, and there is a risk that impurities and the like may enter therefrom. is preferably attached with a dummy module 40d. Of course, membrane modules similar to membrane modules 20a to 20c may be provided in line d.

The particulate removal membrane device comprises a supply pipe 31, a concentrated water pipe 32 and a permeate pipe 33 which are connected to its inlet, concentrated water outlet and permeated water outlet, respectively. Water to be treated, that is, supply water is supplied to the supply pipe 31 from, for example, the degassing device 16 in the preceding stage. A flow meter 34 and an on-off valve 35 are provided between the permeated water pipe 33 and the permeated water outlet of the particulate removal membrane device. Although the flowmeter 34 is provided before the on-off valve 35 in FIG. 2, the flowmeter 34 may be provided either before or after the on-off valve 35 . The flowmeter 34 is permeate water measuring means, and measures the flow rate of ultrapure water flowing out from the microparticle removal membrane device. The flow rate measured by the flow meter 34 is the total flow rate of the permeated water from the multiple membrane modules (here, the membrane modules 20a to 20c) arranged in parallel as water from which fine particles have been removed. It is used to control the operation of ultrapure water production equipment in order to maintain the production and supply of ultrapure water to meet the demand for water.

Corresponding to the line a, an inlet pipe 21a is connected to the supply pipe 31, and the inlet pipe 21a is provided with an on-off valve 24a. The inlet pipe 21a is for connecting the inlet of the membrane module 20a and the supply pipe 31 when the membrane module 20a is attached to the position of the line a. Similarly, an outlet pipe 22a is connected to the concentrated water pipe 32, an on-off valve 26a is provided in the outlet pipe 22a, an outlet pipe 23a is connected to the permeated water pipe 33, and an on-off valve is connected to the outlet pipe 23a. 28a is provided. The outlet pipes 22a and 23a are for connecting the concentrated water outlet and the permeated water outlet of the membrane module 20a attached to the line a to the concentrated water pipe 32 and the permeated water pipe 33, respectively.

Further, a branch pipe 41a communicating with a chemical injection line for introducing a sterilizing solution or a cleaning solution is connected to the inlet pipe 21a, and the branch pipe 41a is provided with an on-off valve 25a. The connection position of the inlet pipe 21a of the branch pipe 41a is closer to the attachment position of the membrane module than the on-off valve 24a. Similarly, branch pipes 42a and 43a communicating with bypass lines are connected to the outlet pipes 22a and 23a, respectively, and the branch pipes 42a and 43a are provided with on-off valves 27a and 29a, respectively. The connection positions of the branch pipes 42a and 43a to the outlet pipes 22a and 23a are respectively on the membrane module mounting position side of the on-off valves 26a and 28a. As will be described later, the branch pipe 43a located on the permeation side is preferably provided with a flow meter for measuring the permeation amount of the liquid used for sterilization, cleaning, and rinsing and the flow rate of the blown liquid. .

Similarly to line a, inlet pipe 21b, outlet pipes 22b, 23b, branch pipes 41b, 42b, 43b and on-off valves 24b, 25b, 26b, 27, 28b, 29b are provided corresponding to line b. Corresponding to line d, inlet pipe 21c, outlet pipes 22c, 23c, branch pipes 41c, 42d, 43c and on-off valves 24c, 25c, 26c, 27c, 28c, 29c are provided, and inlet pipe 21d , outlet pipes 22d, 23d, branch pipes 41d, 42d, 43d, and on-off valves 24d, 25d, 26d, 27d, 28d, 29d. As will be described later, in this embodiment, it is preferable to use the supply water supplied from the supply pipe 31 to the inlet pipes 21a to 21d as the pure water used for preparing the chemical solution and rinsing the membrane module. The direction is made to match the flow direction of the feed water when removing particulates in each membrane module.

First, with reference to FIG. 2, the operation of the fine particle removing membrane device during normal operation, that is, when fine particles are removed from the supply water and the permeated water is discharged as ultrapure water, will be described. Here, it is assumed that the permeated water is discharged at a flow rate of 30 t/h. At this time, since the three membrane modules 20a to 20c are operated in parallel, the amount of permeated water per membrane module is 10 t/h. As the membrane modules 20a to 20c, those having a processing capacity of 15 t/h or more in terms of the amount of permeated water are used. Examples of UF membranes having a throughput of 15 t/h or more used in particulate removal membrane devices include OLT-6036 HA (manufactured by Asahi Kasei Corporation) and NTU-3306-K6R UP (manufactured by Nitto Denko Corporation). Since the line d to which the dummy module 40d is attached is not used, the permeated water amount is 0t/h. In order to supply the feed water supplied to the inlet pipe 31 to the membrane modules 20a to 20c, to guide the concentrated water from the membrane modules 20a to 20c to the concentrated water pipe 32, and to guide the permeated water to the permeated water pipe 33, the The valves 24a-24c, 26a-26c, 28a-28c are opened. Since water does not flow through the dummy module 40d, the on-off valves 24d, 26d and 28d are closed. Further, since the branch pipes 41a-41d, 42a-42d, 43a-43d are not used, the on-off valves 25a-25d, 27a-27d, 29a-29d are also closed.

Next, with reference to FIG. 3, operations for sterilizing, cleaning, and rinsing another membrane module 20d while continuing the removal of fine particles by the membrane modules 20a to 20c will be described. Assuming that sterilization, washing and rinsing are performed in line d, membrane module 20d is attached to line d. During sterilization and cleaning, the on-off valves 24d, 26d, and 28d remain closed. Then, the on-off valves 25d, 27d, and 29d provided in the branch pipes 41d, 42d, and 43d are opened to supply the sterilizing liquid from the chemical injection line to the membrane module 20d through the branch pipe 41d. As a result, the membrane module 20d is sterilized, and the sterilized waste liquid is discharged to the bypass line through the branch pipes 42d and 43d. Subsequently, the cleaning liquid is supplied to the membrane module 20d through the branch pipe 41d to clean the membrane module 20d. The washing liquid is discharged to the bypass line through the branch pipes 42d and 43d. At least one of the branch pipes 42d and 43d on the outlet side of the membrane module 20d is provided with a A flow meter 36d is provided as branch pipe measuring means. Although it is conceivable to provide the flow meter 36 in the branch pipe 41d on the inlet side of the membrane module 20d, in order to reduce the possibility of contamination of the membrane module 20d as much as possible, the branch pipe on the outlet side of the membrane module 20d 42d and 43d are preferably provided with flowmeters, and more preferably, flowmeters are provided on the outlet sides of the on-off valves 27d and 29d in the branch pipes 42d and 43d. In particular, since pure water or ultrapure water may continue to flow through the membrane module 20d during a rinsing step or the like, the flowmeter 36d is connected to the branch pipe 43d connected to the outlet on the permeation side of the membrane module 20d, as shown in FIG. It is preferably provided. Also, the flow meter does not need to be permanently installed, and may be installed during sterilization, cleaning, and rinsing. For example, if an ultrasonic flowmeter is used, it can be attached and detached from the line at any time, and the possibility of contamination is low. A flow meter may also be provided in the bypass line. In the example shown in FIG. 3, the flow rate of the chemical solution on the permeation side of the membrane module 20d is at/h. Effective sterilization, cleaning and rinsing can be performed based on the values measured by the flow meter 36d.

In this embodiment, both the sterilizing liquid and the cleaning liquid can be diluted and prepared on the spot before being supplied to the membrane module 20d. The water supplied to the fine particle removal membrane device is, for example, the water supplied from the degassing device 16 in the ultrapure water production device shown in FIG. It can be used satisfactorily for diluting preparations of liquids and cleaning liquids. Therefore, the on-off valve 24d provided in the inlet pipe 21d to the membrane module 20d is opened to supply water to the microparticle removal membrane device to the membrane module 20d, and at the same time, the chemical solution can be injected from the branch pipe 41d. The chemical solution is diluted with supply water in the inlet pipe 21d and introduced into the membrane module 20d. By introducing the chemical solution into the membrane module while diluting the chemical solution with the supplied water, the flow rate of the concentrated chemical solution supplied to the branch pipe 41d can be reduced while increasing the flow velocity of the chemical solution within the membrane module 20d. In addition, a small amount of concentrated chemical solution can be injected using a small pump or nitrogen pressure from a canister tube. When using an aqueous ammonia solution for cleaning the membrane module 20d, for example, by injecting 1 m ³ /h of pure water, that is, 30% by weight of concentrated ammonia water with respect to the feed water, at a rate of 0.4 L/h, pH of 10 can be obtained. Alternatively, immersion sterilization or immersion cleaning may be performed in a state in which the chemical solution is enclosed in the membrane module 20d by operating the on-off valves 25d, 27d, and 29d. The chemical solution injection line connected to the branch pipe 41d need not always be installed, and the chemical solution injection line may be provided when necessary. In order to prevent foreign matter, fine particles, etc. from entering the membrane module 20d during sterilization or cleaning, it is preferable to provide a microfiltration membrane (MF) or the like at the entrance of the chemical solution to the branch pipe 41d.

After the sterilization and cleaning are completed, the chemical solution in the membrane module 20d is discharged. When discharging the chemical solution from the membrane module 20d, the injection of the chemical solution from the branch pipe 41d is stopped, and the on-off valve 25d is also closed. Then, the on-off valve 24d is opened to supply the supply water to the membrane module 20d and push out the chemical solution from the branch pipes 42d and 43d. Also, in order to discharge the chemical solution remaining in the branch pipe 41d, the branch pipe 41d is disconnected from the chemical solution injection line, and instead, the on-off valve 25d is opened so that the chemical solution flows in the opposite direction to that when the chemical solution is supplied. It is preferable to flow water into the branch pipe 41d and blow the chemical solution in the branch pipe 41d. The process of supplying pure supply water to the membrane module 20d, blowing the chemical solution, and draining the water is called a rinsing process. This rinsing process is an extremely important process and is performed until the effect of the chemical solution disappears. It is preferable to check the water quality of the permeated water from the membrane module 20d in order to determine whether the influence of the chemical solution has disappeared, that is, whether there is no problem with the water quality of the permeated water. Water quality can be confirmed by measuring, for example, TOC (Total Organic Carbon) concentration, specific resistance, number of fine particles per unit volume, hydrogen ion concentration (pH), or metal ion concentration. In the present embodiment, ultrapure water can be produced in the membrane modules 20a to 20c and supplied to the point of use in parallel with the sterilization, cleaning, and rinsing of the membrane module 20d. It does not matter if the time required for cleaning and rinsing and the time for checking the water quality of the water permeated through the membrane after rinsing are lengthened. After sterilizing, cleaning, and rinsing the membrane module 20d, and after confirming that there is no problem with the water permeating the membrane after rinsing, the on-off valves 25d, 27d, and 29d are closed.

The membrane module 20d provided in line d can contribute to the production of ultrapure water after sterilization, cleaning and rinsing as described above. When the membrane module 20d contributes to the production of ultrapure water, the on-off valves 24d, 26d, and 28d are opened so that the membrane module 20d is arranged in parallel with the membrane modules 20a to 20c and removes fine particles in the feed water. At this time, the flow rate of permeated water required for the fine particle removal membrane apparatus as a whole is still 30 t/h, so the permeated water rate per membrane module 20a to 20d is 7.5 t/h, and the pump 12 is driven. By controlling or adjusting the opening of the flow control valve 17, the supply pressure and supply flow rate to the point of use are adjusted. When one of the membrane modules is to be sterilized or cleaned while the four membrane modules 20a to 20d are operated in parallel, the supply of water to that membrane module is stopped and the other membrane modules are operated. is set so that the amount of permeated water is 10 t/h, and the membrane module is sterilized, washed, and rinsed by the same procedure as described above for the membrane module 20d, and then the membrane module is washed again with ultrapure water. Contribute to manufacturing.

Next, replacement of the membrane module in the particulate removal membrane apparatus shown in FIG. 2 will be described. Here, it is assumed that membrane modules 20a to 20c are attached to lines a to c, respectively, and that each of these membrane modules 20a to 20c removes fine particles in the treated water at a permeation rate of 10 t/h. Consider replacing one of the three membrane modules 20a to 20c, for example, the membrane module 20c provided in the line c. When replacing the membrane module 20c, first, the on-off valve 24c of the inlet pipe 21c connected to the membrane module 20c and the on-off valves 26, 28c of the outlet pipes 22c, 23c are closed. Since it is necessary to maintain the total permeation water flow rate of the microparticle removal membrane device at 30 t/h, the drive control or flow rate of the pump 12 is controlled so that the permeation water flow rate of each of the membrane modules 20a and 20b is 15 t/h. By adjusting the opening degree of the regulating valve 17, the supply pressure and supply flow rate to the point of use are adjusted. Then, as shown in FIG. 4, the membrane module 20c is removed from the particle removal membrane device.

By removing the membrane module 20c, the line c becomes an empty line. A dummy module may be attached to the line c, but another membrane module that has been sterilized, washed and rinsed is attached to the line c, and this newly attached membrane module and the existing membrane modules 20a and 20b are arranged in parallel. It may be operated to remove particulates in feed water to produce ultrapure water. When a new membrane module is attached to the line c, the permeate water amount of each membrane module is returned to the original 10 t/h. In the configuration shown in FIGS. 2 and 3, if sterilization and cleaning are performed only in line d, the membrane module that has been sterilized, cleaned, and rinsed in line d is attached to line c, which has become an empty line. be able to. The removed membrane module 20c may be attached to the line d for sterilization, cleaning and rinsing.

Next, the chemical solution used for sterilizing and cleaning the membrane module in this embodiment will be described in detail. First, the cleaning liquid will be explained. It is preferable to use an alkaline aqueous solution as the cleaning liquid. The alkaline aqueous solution has the effect of removing fine particles. As alkalis, organic alkalis such as tetramethylammonium hydroxide (TMAH) and trimethyl-2-hydroxyethylammonium hydroxide (also referred to as choline), and inorganic alkalis such as ammonia are used. Inorganic alkalis, which are metal hydroxides such as sodium hydroxide and potassium hydroxide, can also be used. Use is generally avoided.

A hydrogen peroxide solution is preferably used as the sterilizing solution. Hydrogen peroxide has a bactericidal effect. When hydrogen peroxide solution is used as the sterilizing liquid, the concentration of hydrogen peroxide is preferably 0.1% by weight or more and 10% by weight or less, more preferably 1% by weight or more and 5% by weight or less. When 1% by weight hydrogen peroxide solution is used as the sterilizing solution, 1% by weight hydrogen peroxide solution is prepared in advance by diluting commercially available 30% by weight hydrogen peroxide solution 30 times with pure water, The prepared hydrogen peroxide solution may be injected from a branch pipe. Alternatively, a 30% by weight hydrogen peroxide solution may be directly injected into the branch pipe and diluted 30 times by mixing with the supply water (pure water) flowing through the inlet pipe. In the case shown in FIG. 3, while supplying pure water at a flow rate of 29 L/min through the inlet pipe 21d, 30% by weight hydrogen peroxide solution is supplied at a flow rate of 1 L/min through the branch pipe 41d. As a result, 1% by weight hydrogen peroxide solution is supplied to the membrane module 20d at a flow rate of 30 L/min. As in the case of cleaning with ammonia water described above, a sufficient sterilization effect can also be obtained by an immersion treatment in which a hydrogen peroxide solution is enclosed in the membrane module instead of passing the liquid through. When the membrane module is sterilized by immersion, an immersion time of about several hours is sufficient.

If the membrane modules 20a to 20d and the dummy module 40d are collectively referred to as modules, the particle removal membrane apparatus of the present embodiment described above has a plurality of modules, and each of these modules has a particle removal module. A plurality of membrane modules 20a-20d comprising membranes will be included. The membrane module can be replaced with a dummy module. At least part of the plurality of membrane modules are installed in parallel with each other, and at least one of the membrane modules installed in parallel is defined as a first membrane module (for example, membrane modules 20c and 20d). A membrane module different from the membrane module of 1 is used as a second membrane module (for example, membrane modules 20a and 20b), and the particulate removal membrane device passes water through the first membrane module separately from the second membrane module. Inlet pipes 21a to 21d and outlet pipes 22a to 22d and 23a to 23d as flow paths, and supply pipe 31, which is the first pipe provided in common to the membrane modules arranged in parallel, It is provided with a concentrated water pipe 32 and a permeate water pipe 33, which are second pipes provided in common for the membrane modules arranged in parallel. Since the concentrated water pipe 32 is unnecessary in the dead end filtration membrane module, the second pipe is the permeated water pipe 33 .

In the microparticle removal membrane apparatus of the present embodiment, as switching means for switching the flow path, an on-off valve 24a is provided between the inlet of each of the membrane modules installed in parallel and the supply pipe 31, which is the first pipe. 24d, and on-off valves 26a to 26d provided between the outlets (concentration side and permeate side) of the membrane modules installed in parallel and the second piping, ie, the concentrated water piping 32 and the permeated water piping 33. , 28a-28d are provided. By the switching operation of these on-off valves, the first membrane module and the second membrane module are completely separated with respect to the path for discharging water, and the water is passed through the second membrane module to remove fine particles. At times, it is possible to replace the first membrane module and/or pass the chemical or rinse water through the first membrane module.

In the fine particle removal membrane apparatus of this embodiment described above, each of the lines a to d is provided with an on-off valve in the inlet pipe, and an on-off valve is provided on the outlet pipes on the concentration side and the permeate side. However, for lines in which the membrane module is not to be removed or cleaned, it is not necessary to provide these on-off valves, and there is no need to provide branch pipes connected to the inlet pipe and the outlet pipe, respectively. In addition, it is planned to replace or remove the membrane module, but it is not necessary to provide a branch pipe in a line in which the membrane module is not cleaned while it is still attached to the line.

Next, a fine particle removal membrane device according to another embodiment of the present invention will be described with reference to FIGS. 5 and 6. FIG. 2, 3, and 4, the four water flow lines provided in the embodiment shown in FIGS. It is configured so that it can be sterilized and cleaned. However, if the process of removing fine particles in the feed water to produce ultrapure water and the process of sterilizing and cleaning the membrane module itself are carried out in the same water flow line, malfunction may cause to the point of use. Therefore, in the microparticle removal membrane apparatus shown in FIG. 5, in the microparticle removal membrane apparatus shown in FIG. are independent. That is, the particle removal membrane device shown in FIG. 5 is obtained by removing the outlet pipes 22d and 23d and the on-off valves 26d and 28d provided in the outlet pipes 22d and 23d from the particle removal membrane device shown in FIG. . Assuming that the membrane module 20d is already attached to the line d, the branch pipe 42d is provided so as to be directly connected to the concentrate outlet of the membrane module 20d, and the branch pipe 43d is directly connected to the permeate outlet of the membrane module 20d. is provided as follows. Furthermore, the tip of the supply pipe 31 is connected to a bypass line via an on-off valve 37 so that the supply water in the supply pipe 31 can be blown.

In this fine particle removal membrane device, during normal operation, as shown in FIG. By being closed, a process of particulate removal from the feed water is performed in each of lines ac. At this time, the amount of water permeated through each of the membrane modules 20a to 20c is 10 t/h, and the amount of ultrapure water produced by the entire microparticle removal membrane apparatus is 30 t/h. In the line d, which is a water passage line exclusively for sterilization and cleaning, sterilization, cleaning and rinsing of the membrane module 20d are performed as necessary. In FIG. 5, sterilization, cleaning and rinsing of membrane module 20d attached to line d have already been completed, and on-off valves 24d, 25d, 27d and 29d associated with line d are all closed.

Assume that the membrane module 20c of the line c needs to be cleaned or replaced. In that case, the on-off valves 24c, 26c, and 28c are closed to disconnect the membrane module 20c from the supply pipe 31, the concentrated water pipe 32, and the permeated water pipe 33, and then the membrane module 20c is removed from the particulate removal membrane apparatus. At this time, the supply pressure and the supply flow rate to the point of use are adjusted so that the amount of permeated water in the membrane modules 20a and 20b is 15 t/h. Then, as shown in FIG. 6, a new membrane module that has already been sterilized and cleaned, for example, a membrane module 20d that has been sterilized, cleaned and rinsed in the line d, is placed in the line instead of the removed membrane module 20c. c. When a new membrane module is installed, there is a possibility that fine particles and the like may enter the membrane module during installation, so it is preferable to rinse the membrane module again. When performing this rinsing, after opening the on-off valves 27c and 29c of the branch pipes 42c and 43c, deionized water is supplied through the inlet pipe 21c and the on-off valve 24c of the inlet pipe 21c. Rinse the membrane module. A flow meter 36c is preferably provided in the branch pipe 43c in order to measure the amount of water permeated by rinsing. After the rinsing is completed, the on-off valves 25c, 27c, 29c are closed, the on-off valves 24c, 26c, 28c are opened, and the removal of fine particles by the membrane module provided on the line c is restarted. Since three membrane modules are arranged in parallel again to remove fine particles, the supply pressure and supply flow rate to the point of use are adjusted so that the permeate volume of each membrane module is 10t/h. do. If the amount of permeated water during sterilization and washing is at/h, and the amount of permeated water during rinsing is bt/h, the amount of permeated water during rinsing should be less than that during sterilization and washing. It is preferable to avoid That is, it is preferable to set the amount of permeated water so that b≧a.

As described above, the present invention provides a fine particle removal apparatus provided in an ultrapure water production apparatus without interrupting the supply of ultrapure water to a point of use even when the amount of treated water in the ultrapure water production apparatus is large. It is possible to perform at least one of cleaning and sterilization of a part of the membrane modules, and it is not necessary to provide a new cleaning and sterilization device, so space saving and low cost can be realized.

13 heat exchanger 14 ultraviolet oxidizer 15 non-regenerative ion exchanger 16 deaerator 17 flow control valve 19 fine particle removal membrane device 20a-20d membrane module 21a-21d inlet pipe 22a-22d, 23a-23d outlet pipe 24a-24d , 25a to 25d, 26a to 26d, 27a to 27d, 28a to 28d, 29a to 29d On-off valve 31 Supply pipe 32 Concentrated water pipe 33 Permeated water pipe 40d Dummy module 41a to 41d, 42a to 42d, 43a to 43d Branch pipe

Claims (7)

In a particle removal membrane device having a plurality of modules including at least a plurality of membrane modules provided with particle removal membranes,
At least part of the plurality of membrane modules are installed in parallel with each other,
At least one of the membrane modules installed in parallel is defined as a first membrane module, and a membrane module different from the first membrane module is defined as a second membrane module. a channel through which water can flow in a manner distinguishable from the second membrane module;
a switching means for switching the flow path;
a first pipe, a second pipe, and a third pipe provided in common for the membrane modules arranged in parallel;
has
The switching means includes a first on-off valve provided between the inlet of each of the membrane modules installed in parallel and the first pipe, and an outlet of each of the membrane modules installed in parallel. and a second on-off valve provided between the second pipe,
By switching the first on-off valve and the second on-off valve, when water is being passed through the second membrane module to remove fine particles, the first membrane module is replaced and the second membrane module is removed. enabling execution of at least one of passing the chemical liquid through the membrane module of 1;
The particulate removal membrane device includes, for each of the first membrane modules, a first valve connected to a pipe between the first on-off valve corresponding to the first membrane module and an inlet of the first membrane module. between the branch pipe, the third on-off valve provided in the first branch pipe, the second on-off valve corresponding to the first membrane module, and the outlet of the first membrane module A second branch pipe connected to the pipe, and a fourth on-off valve provided in the second branch pipe,
The outlet of the first membrane module is a permeated water outlet that is the outlet of water that has permeated the fine particle removal membrane provided in the first membrane module, and the first membrane module further comprising a concentrated water outlet, which is an outlet for water that has not permeated the fine particle removal membrane provided in the membrane module,
The switching means includes a fifth on-off valve for each of the membrane modules installed in parallel, and the fifth on-off valve is connected to the concentrated water outlet of each of the membrane modules installed in parallel and the third pipe. is provided between
The particulate removal membrane device is connected to a pipe between the fifth on-off valve corresponding to the first membrane module and the concentrated water outlet of the first membrane module for each of the first membrane modules. further comprising a third branch pipe and a sixth on-off valve provided in the third branch pipe;
A microparticle removal membrane device, wherein microparticles contained in the water are removed by supplying water to at least one of the membrane modules. 2. The particle removal membrane device according to claim 1, wherein said plurality of modules comprise said plurality of membrane modules and dummy modules not provided with said particle removal membrane. 3. The particle removal membrane device according to claim 1 , wherein said particle removal membrane is an ultrafiltration membrane. An ultrapure water production apparatus for producing ultrapure water, characterized by having the particle removal membrane device according to any one of claims 1 to 3 at a position of an end portion from which the produced ultrapure water is discharged. , ultrapure water production equipment. 5. A method for producing ultrapure water using the ultrapure water production apparatus according to claim 4, wherein the switching means disconnects the first membrane module from the water flow line including the second membrane module, and then A method for producing ultrapure water, comprising supplying a chemical solution to the first membrane module to perform at least one of sterilization and cleaning of the first membrane module. 6. The manufacturing method according to claim 5 , wherein the chemical solution is at least one of an alkaline aqueous solution and a hydrogen peroxide aqueous solution. 6. Control is performed to increase the water flow rate per membrane module for removing fine particles when the number of membrane modules for removing fine particles in the membrane modules installed in parallel is reduced. 6. The manufacturing method according to 6.

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