JPH06170178A - Hollow fiber membrane module filtration equipment - Google Patents

Abstract

(57) [Summary] [Purpose] A liquid containing fine particles and suspended substances is continuously filtered,
Moreover, a hollow fiber membrane module capable of removing clogging of the hollow fiber membrane by periodically performing backwashing is provided. [Structure] In the middle of a filtered water line for supplying filtered water filtered by a hollow fiber membrane module having a hollow fiber membrane housed in a container to the outside of the container, the filtered water is used for a certain period of time by utilizing gas pressure. A hollow fiber membrane module filtration device, characterized in that a filtered water backflow tank is provided for backflow into the hollow fiber membrane module.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a filtration device using a hollow fiber membrane module for performing a liquid filtration operation and a method of using the filtration device.

[0002]

2. Description of the Related Art General industrial water contains many SS components, fine particles, dust, bacteria, algae, etc. If used as it is, clogging of water pipes, bacterial growth, It is likely to cause problems such as scale accumulation in the line. Conventionally, various methods such as sand filtration, coagulation filtration, coagulation-precipitation treatment, and cartridge filter filtration have been used in order to remove these water-mixed components, depending on the application. As a new method replacing these general filtration methods, filtration using a porous hollow fiber membrane has recently been put into practical use. The water treatment and filtration using hollow fiber membranes have rapidly spread in recent years, and the fields of application thereof are also expanding year by year.

In filtration of hollow fiber membranes, the hollow fiber membranes are processed into a product form in which thousands to tens of thousands are bundled into a bundle and the ends are fixed with an adhesive. The products processed into these product forms are called hollow fiber membrane modules or modules. Many types of hollow fiber membrane modules capable of filtering liquid have been proposed in the past. Especially as the initial one, there are a filtration module used in combination with an appropriate pretreatment means, one for the purpose of reverse osmosis filtration, one for the purpose of dialysis, etc.
Many module forms have been proposed mainly for these applications, and the main ones thereof are Japanese Patent Publication No. Sho 48.
-28380, JP-A-49-69550,
There are those described in JP-A No. 53-100176. All of these were usually disposed of, or washed with clear water or chemical water or flushed at a stage where a certain amount or more of dirt adhered.

On the other hand, recently, a method has been tried in which the hollow fiber membrane module shape is devised so that the adhered substances on the surface of the hollow fiber membrane are regularly removed by air to recover the performance of the hollow fiber membrane. ing. Japanese Unexamined Patent Publication No. 61-263605 discloses that a hollow fiber membrane is incorporated in a U-shape and used by being housed in a container, and air is regularly introduced from an air introduction port provided at the bottom of the container. The hollow fiber membrane is vibrated by air bubbling to try to remove deposits on the membrane surface. Further, Japanese Patent Laid-Open No. 60-206415 discloses a module with both ends fixed in which hollow fiber membranes are arranged around a central pipe, which is incorporated into a container in the same manner as described above, and air bubbling removes deposits on the surface of the hollow fiber membranes. To do. The practical application of these technologies has already started.

Further, Japanese Unexamined Patent Publication (Kokai) No. 51-110482 discloses a device for backwashing a hollow fiber membrane in sequence with a filtrate, and in Japanese Unexamined Patent Publication (Kokai) No. 48-34763, fine particles adhering to the membrane are removed by compressed air. It is also shown that the solution is then washed back with a filtrate or other solution.

[0006]

In the water treatment by the hollow fiber membrane module, it is an excellent method to remove the deposits on the surface of the hollow fiber membrane by air bubbling or backwashing.
By removing (cleaning) the deposits on the membrane surface by such a method, the state before filtration can be almost restored, the filtration performance is also almost restored, the life of the hollow fiber membrane module is extended, and it is economical. In the past, a pump was used to supply backwash water, but for that reason a pump must be installed for backwashing, which is a simpler method from the standpoint of equipment burden and maintenance. A means for supplying backwash water was required.

[0007]

An object of the present invention is to provide a filtered water line, which supplies filtered water filtered by a hollow fiber membrane module having a hollow fiber membrane housed in a container, to the outside of the container,
This is basically achieved by a hollow fiber membrane module filtration device characterized in that a filtered water backflow tank is provided for backflowing filtered water to the module side for a certain period of time using gas pressure.

[0008]

An embodiment according to the present invention is shown in FIG.

The feed water to be filtered is guided by a raw water feed pump 3 to a porous hollow fiber filtration membrane module (hereinafter referred to as a hollow fiber membrane module) 1, where a filtration treatment is performed.

The hollow fiber membrane module contains a large number of porous hollow fiber membrane bundles in a container and has a raw water supply port 5, a filtered water outlet 10, and a module drain port 6 in a part of the container. . The feed water is filtered through innumerable fine pores open on the surface of the hollow fiber membrane, and only clear water from which SS components, fine particles, dust, and the like have been removed permeates inside the hollow fiber membrane, and from the filtered water outlet. It is taken out as filtered water.

The filtered water filtered by the hollow fiber module passes through the filtered water outlet 10 and the filtered water line 24, and enters the filtered water backflow tank 2 through the filtered water backflow tank 11 and the filtered water backflow tank 2. Then, it is obtained from the filtered water outlet 16 of the filtered water backflow tank. The filtered water backflow tank 2 is provided with a filtered water backflow air supply port 4 for press-fitting with air pressure of the backwash water of the present invention.

In the filtration of the hollow fiber membrane module, the larger the raw water pressure is, the larger the amount of filtered water is. However, as the filtration time elapses, the SS components, fine particles, etc. adhere to the membrane surface and the hollow fiber membrane is more or less clogged. It usually occurs and the amount of filtered water per the same pressure gradually decreases.
Therefore, at an appropriate time when the amount of filtered water decreased due to the progress of clogging of the hollow fiber membrane, a washing operation such as backwashing or air bubbling was performed, and the filtered water volume of the hollow fiber membrane was brought to a level close to that before clogging. Will need to be recovered.

The method of using the hollow fiber membrane module is not limited and can be set according to the user's wish. Examples of the operating method include an operating method in which the amount of filtered water is changed while keeping the pressure constant, a method in which the amount of filtered water is kept constant while automatically or manually controlling the pressure, and a module is connected to an appropriate supply water source to control the pressure. There is a method of operating without changing the temperature.

FIG. 2 shows a conventional hollow fiber membrane module filtration device, which performs backwashing or backwashing in combination with air bubbling when the amount of filtration of the feed water decreases and the supply pressure rises at an appropriate time. To do. At this time, first, the feed water inlet valve 4 and the filtered water valve 22 are closed, and the module overflow valve 9 is opened. The backwashing pump 21 is operated to feed backwashing water from the filtered water backflow tank 2 to start backwashing, and after washing for a certain period of time, the module drain valve 7 is opened to drain the washing liquid. After that, the module drain valve 7 is closed, the filtered water valve 22 and the feed water inlet valve 4 are opened, and feed water is fed. The module overflow valve 9 is closed when the inside of the module is filled with the supply water and the supply water overflows.

This operation is repeated many times every time the filtration amount of the feed water decreases and the feed pressure becomes a constant value.

The inventors of the present invention have conducted extensive studies on a method of supplying backwash water to the module without using a pump having a low operating rate for backwashing in washing the hollow fiber membrane module. I found it.

By adopting the method of supplying backwash water by air pressure according to the present invention, a backwash effect equivalent to the example using the conventional pump can be obtained without using a pump for supplying backwash water. I found that I could be. FIG. 1 is an explanatory view of an apparatus equipped with an air pressure backwash water supply apparatus of the present invention. The cleaning conditions are exactly the same as in Fig. 2, but the pump for supplying the backwash water is not required, so the cost of the device is reduced,
Also, problems such as pump maintenance can be solved at the same time. A compressed air line is often attached to the factory where the equipment is installed, and especially in the case of an apparatus that also performs air bubbling at the same time, compressed air will be used. It is much simpler and more economical than a device that uses a pump to perform.

FIG. 3 and FIG. 4 are schematic views of a filtered water backflow tank. The tank is provided with a filtered water backflow tank filtered water inlet 11, a filtered water backflow tank filtered water outlet 16, and a filtered water backflow air supply port 14. The filtered water backflow tank is provided with an opening inside the filtered water backflow tank 11 using the insert pipe 23 (FIG. 3) or directly (FIG. 4) near the bottom of the filtered water backflow tank 2. By supplying air from the filtered water backflow air supply port 14, the filtered water in the filtered water backflow tank 2 flows back. The inside of the filtered water backflow tank 11 of the filtered water backflow filtered water inlet 11 is not particularly specified by FIG. 3 or 4 as long as it is installed in a location where the filtered water can be backflowed by air pressure. The installation position of the filtered water backflow filtered water inlet 11 is preferably 1/2, more preferably 1/5 of the effective capacity of the filtered backflow tank 2. Further, it is preferable that the filtered backflow tank filtered water outlet 16 is provided near the upper portion of the filtered backflow tank 2.

The capacity of the tank for the reverse flow of filtered water can be freely selected according to the membrane area of the hollow fiber membrane module and the conditions of use, but in normal use, it is 0.1 to 1 liter per square meter of membrane area. The degree is appropriate. Further, the backwashing interval and the backwashing time are not particularly limited because they vary depending on the use conditions, but a backwashing time of about several tens of seconds to several minutes is usually suitable for 1 hour of filtration. Further, even if the filtered water in the filtered water backflow tank is exhausted during the backwashing, air does not normally pass through the membrane and no problem occurs. Further, when the pore size of the membrane is large, air may pass through the membrane, but this does not hinder the backwashing effect and is not a problem. Therefore, it is not necessary to take into account the fact that the water in the tank runs out. For example, a timer or the like can be used to set a sufficient time for all the water in the filtered water backflow tank to run out. When it is not preferable to send air into the module for convenience, the backflow rate may be used for control.

The filtered water backflow tank 2 is not particularly limited where it is provided along the filtered water line 24 as long as it does not hinder the reverse flow of the filtered water to the hollow fiber membrane module 1. For example, the filtered water backflow tank may be directly connected to the filtered water outlet 10, or may be provided at the end of the filtered water line, or the hollow fiber membrane module 1 and the filtered water backflow. Even if a valve or some auxiliary tank is interposed between the water tank 2 and the tank 2, it is not particularly limited as long as it does not hinder the reverse flow of the filtered water.

The hollow fiber membrane module of the present invention may be of any type as long as it is a filtration element using a bundle of porous hollow fiber membranes as a filtering material. The preferred shape of the hollow fiber membrane module is a structure in which a hollow fiber membrane is opened by cutting one end or both ends of this adhesive seal part after sealing both ends or mold ends of a bundle of a large number of hollow fiber membranes. And
It is usually housed inside the container as an integrated type or a built-in type.

The hollow fiber membrane module includes those that perform microfiltration and ultrafiltration, those that perform dialysis and reverse osmosis of substances through the hollow fiber membrane, and those that perform not only mass transfer between liquids but also liquids and gases. There are a wide variety of types and applications, including those that transfer substances and those that transfer substances between gases.

The hollow fiber membrane material constituting the hollow fiber membrane module used in the present invention is not particularly limited as long as it is a porous hollow fiber membrane, but polyethylene, polypropylene,
Polysulfone, polyether sulfone, polyvinyl alcohol, cellulose acetate, polyacrylonitrile, and other materials can be selected. Among these, a particularly preferable hollow fiber membrane material is a hollow fiber membrane made of a polymer containing at least one component of acrylonitrile. The most preferable acrylonitrile-based polymer is at least 50 mol% or more of acrylonitrile, preferably 60 mol% or more and 50% or less of one or more vinyl compounds having copolymerizability with the acrylonitrile. Is an acrylonitrile polymer composed of 0 to 40 mol%. Further, a mixture of two or more kinds of these acrylonitrile-based polymers and further another polymer may be used. The vinyl compound may be any known compound having copolymerizability with acrylonitrile and is not particularly limited, but preferable copolymer components include acrylic acid, itaconic acid, methyl acrylate, methyl methacrylate, Examples thereof include vinyl acetate, sodium allyl sulfonate, sodium p-styrene sulfonate, and the like.

The next preferable hollow fiber material is
It is composed of one or more olefin polymers such as ethylene propylene or 4-methylpentene, and has a hollow fiber membrane shape with a major axis of 0.1 to 1 μm and a minor axis of 0.05.
Those having a slit-shaped fine pore of ˜0.5 μm are suitable.

[0025]

【Example】

Example 1 A filtration device including a raw water supply pump 3, a hollow fiber membrane module 1, and a filtered water backflow tank 2 was manufactured. This filter uses air pressure when supplying the backwash permeate to the module. The hollow fiber membrane module has an outer diameter of 450 μm, an inner diameter of 320 μm, and an average pore size of 0.
01 μm polyacrylonitrile porous hollow fiber membrane 100
A hollow fiber membrane having a diameter of 12 c, which was obtained by fixing both ends of a hollow fiber membrane consisting of 00 fibers with an epoxy adhesive and then cutting one end of the adhesive fixing portion to open the hollow fiber membrane and store it inside the container.
A hollow fiber membrane module with a length of 100 cm is used. Using this apparatus, lake water was pumped up by the raw water supply pump 3 and supplied to the hollow fiber membrane module 1 for long-term continuous filtration treatment. In the filtration process, the flow rate is adjusted to 4 liters / minute by automatic adjustment of the pressure, and even if the module is clogged, the pressure increases according to the degree and the predetermined flow rate is maintained. There is. At the start of operation, the pressure at the module inlet is 0.3 kg / cm
^Although it was ² G, the pressure gradually started to increase from the start of the operation, and the pressure reached 1.0 kg / cm ² G in 30 hours. Therefore, the feed water inlet valve 4 and the filtered water backflow tank filtered water outlet valve 17 are closed, the module overflow valve 9 is opened, the filtered water backflow air valve 15 is opened, and the backwash water is sent from the filtered water backflow tank 2. Backwash was started. After a certain period of time, the module drain valve 7 was opened to drain the wash water, then the module drain valve 7 was closed, the filtered water backflow tank filtered water outlet valve 17 and the feed water inlet valve 4 were opened, and normal operation was started.

The effect of backwashing was exactly the same as that of the conventional filtration device for supplying backwash water with a pump.

[0027]

EFFECTS OF THE INVENTION According to the present invention, a hollow fiber membrane capable of removing clogging of the hollow fiber membrane by continuously filtering a liquid containing fine particles and suspended substances and periodically performing backwashing or the like. A modular filtration device and method of use thereof are provided.

[Brief description of drawings]

FIG. 1 is an example of a schematic configuration diagram of a filtration device in which a backwash water supply device using air pressure of the present invention is installed.

FIG. 2 is an example of a schematic view of a conventional filtration device.

FIG. 3 is an example of a schematic view of a filtered water backflow tank in which a filtered water inlet is provided via an insert pipe.

FIG. 4 is an example of a schematic view of a filtered water backflow tank in which a filtered water inlet is directly provided.

[Explanation of symbols]

 1: Hollow fiber membrane module 2: Tank for reverse flow of filtered water 3: Raw water supply pump 4: Supply water inlet valve 5: Raw water supply port 6: Module drainage port 7: Module drainage valve 8: Module overflow drainage port 9: Module overflow valve 10: Filtered water outlet 11: Filtered water backflow tank Filtered water inlet 12: Filtered water backflow tank drainage port 13: Filtered water backflow tank drainage valve 14: Filtered water backflow air supply port 15: Filtered water backflow air valve 16: Filtered water backflow tank filtered water outlet 17: Filtered water backflow tank filtered water outlet valve 18: Air bubbling air supply port 19: Air bubbling air valve 20: Backwashing filtered water intake 21: Backwashing Pump 22: Filtered water valve 23: Insert pipe 24: Filtered water line

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location C02F 1/44 H 8014-4D

Claims (5)

[Claims] 1. A filtered water line for supplying filtered water filtered by a hollow fiber membrane module in which a hollow fiber membrane is housed in a container to the outside of the container. A hollow fiber membrane module filtration device, characterized in that a filtered water backflow tank for backflowing to the module side is provided. 2. A filtered water inlet from the hollow fiber membrane module is provided directly or by an insert pipe in the vicinity of the bottom of a filtered water backflow tank, and a filtered water outlet is provided in the tank, and a part of the tank is provided. The hollow fiber membrane module filtration device according to claim 1, wherein an air supply port is provided. 3. A bubbling air supply port for applying air bubbling vibration to the hollow fiber membrane from the lower part of the container of the hollow fiber membrane module at the time of reverse flow operation of the filtered water. Hollow fiber membrane module filtration device. 4. The hollow fiber membrane module filtration device according to claim 1, wherein the membrane material of the porous hollow fiber membrane is a polymer having at least one component of acrylonitrile or an olefin polymer. 5. A filtered water line for supplying filtered water filtered by a hollow fiber membrane module in which a hollow fiber membrane is housed in a container to the outside of the container by utilizing gas pressure for a fixed time. A method for filtering a liquid using a hollow fiber membrane module filtration device, characterized in that a filtered water backflow tank for backflowing to the module side is provided.