JPH04265127A - Hollow fiber filter module - Google Patents

Abstract

PURPOSE:To clean the inside of each U-shaped hollow fiber as well as to make the entire fiber usable for filtration by allowing liq. to flow from one end of the fiber to the other end. CONSTITUTION:In a hollow fiber filter module 1, a liq. chamber 6 is formed at one open end 3 of a bundle 2 of U-shaped hollow fibers and a liq. chamber 7 is formed at the other open end 4. At the time of filtration, filtrate is drawn from a liq. path 13 through liq. paths 9, 10. When the bundle 2 is blocked, a changeover valve 11 is closed and liq. is allowed to flow from the chamber 6 to the chamber 7 through the bundle 2.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hollow fiber filtration module made by polymerizing a large number of hollow fibers used for filtering water, and more particularly to a hollow fiber filtration module whose interior can be easily cleaned.

0002

[Prior Art] A hollow fiber-like filtration membrane (usually called a "hollow fiber", hereinafter referred to as a "hollow fiber") that has a large number of very fine pores for the purpose of removing fine particles, which are impurities in water. ), and a large number of them are bundled together to make a hollow fiber module and used for filtration, etc.

[0003] In this hollow fiber module, a large number of fibers are bundled together, and the ends are fixed by a fixing member.The fixing member forms an open end of each hollow fiber, and a liquid chamber is formed therein. When using a hollow fiber module for filtration, there are two methods: passing the liquid to be filtered inside the hollow fiber and discharging the filtrate to the outside, and another method in which the liquid to be filtered is placed outside the hollow fiber and the liquid is filtered inside the hollow fiber by suction etc. There is a method of obtaining the material by permeating the liquid, but in the latter method, the bundle of hollow fibers is bent into a U-shape, one end and the other end of the bundle of hollow fibers are fixed together with a fixing member, and the fixing member A structure is used in which a liquid chamber is formed on the open end side of the hollow fiber and the filtrate is taken out from the liquid chamber. This hollow fiber filtration module uses, for example, 5,000 U-shaped hollow fibers to obtain a hollow fiber filtration module with an open end for 10,000 fibers, and is easy to manufacture, so it has been widely adopted. .

To explain this hollow fiber filtration module with a diagram, as shown in FIG. 3, one end 3 and the other end 4 of a U-shaped hollow fiber bundle 2 are fixed in a fixing member 5, A liquid chamber 23 is formed at the open end side of the hollow fiber of the fixing member 5, surrounded by the member 22, and the filtrate that has entered the inside of the hollow fiber exits to the liquid chamber 23, and from there to the liquid passage 24.
It is designed to be discharged by By using a large number of hollow fibers bundled together, a sufficiently large amount of water can be obtained. In addition, the length of the U-shaped hollow fiber is set within a range from the fixing member to the lower end of the hollow fiber (bottom of the U-shape) such that resistance due to water flow inside the hollow fiber does not increase, for example, about 60 to 70 cm. ing.

[0005] The hollow fibers used in this hollow fiber filtration module have an excellent water purification function, but it is necessary to filter a large amount of water that contains a relatively large amount of fine colloidal substances. When applied to the field, the hollow fibers tend to become clogged, and in order to recover from the clogging, in addition to the conventional method of flowing water from inside the hollow fibers to flow backwards, air bubbles are raised from below. A method of applying physical vibration to the hollow fiber by applying it to the hollow fiber was devised.

However, with this method, the air bubbles do not reach the inside of the hollow fiber filtration module made up of a large number of hollow fibers, so clogging is difficult to eliminate. Therefore, conventionally, a structure has been considered in which the bottom of the U-shaped portion, which is the end portion of the U-shaped hollow fibers, is hooked onto each piece of the support member to hold the hollow fibers together. (Reference Publication No. 2-13069).

[0007]

[Problems to be Solved by the Invention] However, when filtering is performed using this hollow fiber filtration module, especially when filtering water containing a relatively large amount of fine colloidal substances, etc.
Alternatively, when filtration is performed in a biological treatment tank, it has been found that not only the problem of clogging on the surface of the hollow fibers but also the problem of clogging inside the hollow fibers occurs.

[0008] This is because the liquid to be filtered contains a relatively large amount of fine colloidal substances, and when these fine colloidal substances enter the inside of the hollow fiber through the fine holes of the hollow fiber. The passages within the fibers are extremely narrow and the flow rate of the filtrate is low, especially at the ends of the hollow fibers, where the flow rate or velocity is low, so the filtrate does not flow out from inside the hollow fibers into the liquid chamber and stagnates.

Moreover, when backwashing water is periodically flowed into the inside of the hollow fiber to eliminate clogging on the surface of the hollow fiber, colloidal substances accumulated inside the hollow fiber are difficult to come out from the fine pores. I get stuck at the end of the line. and,
As the filtration work continues, the accumulated amount increases, and since effective filtration is not performed in the accumulated portion, the permeation flux decreases.

[0010] This accumulation inside the hollow fiber cannot be removed by backwashing from the inside of the hollow fiber or by bombarding the surface of the hollow fiber with air bubbles. Even if chemical cleaning is applied to eliminate clogging on the surface of hollow fibers, only strong chemicals are effective in dissolving and removing the internal buildup, and it takes time. Therefore, the damage to the hollow fibers caused by the drug will also increase.

[0011] The inventor considered that the accumulated material could be removed by passing a liquid flow inside the hollow fiber, but in the conventional hollow fiber filtration module shown in FIG. 3, the same liquid pressure is applied to the open end of the hollow fiber. It is similar to backwashing, and the liquid does not flow through it. SUMMARY OF THE INVENTION An object of the present invention is to provide a hollow fiber filtration module in which a filtrate can be extracted from both ends of each U-shaped hollow fiber, and a liquid flow can flow from one end of each hollow fiber to the other end. It is.

0012

[Means for Solving the Problems] The present invention separates the liquid chamber in which one end of the U-shaped hollow fiber is opened by a fixing member and the liquid chamber in which the other end is opened by a fixing member. The liquid flow can flow from one end of the hollow fiber to the other end or vice versa. That is, in the present invention, the hollow fiber bundle is formed into a U-shape, one end of the hollow fiber bundle is fixed with a fixing member, and the open end of the one end is defined to form a first liquid chamber. fixing the other end with a fixing member and partitioning the open end of the other end to form a second liquid chamber, and providing liquid passages connected to the first liquid chamber and the second liquid chamber, respectively; The above object has been achieved by a hollow fiber filtration module characterized in that a switching valve is provided between both liquid passages for communicating with and blocking the two liquid passages.

The hollow fiber filtration module of the present invention will be explained with reference to the drawings. FIGS. 1 and 2 schematically show a hollow fiber filtration module 1 that is an example of the present invention. One end 3 of the U-shaped hollow fiber bundle 2 (shown as one in the diagram for schematic purposes) is fixed with a fixing member 5, and the other end 4 is also fixed with a fixing member 5, One end 3 of the hollow fiber bundle 2
A liquid chamber 6 is formed by dividing the open end of the opening end 4, and the other end 4
A liquid chamber 7 is formed by dividing the open end of the liquid chamber 6 and the liquid chamber 7.
It is separated from the other by a compartment 8. Liquid passages 9 and 10 are provided in the liquid chamber 6 and the liquid chamber 7, respectively, and a liquid passage 12 having a switching valve 11 is provided between the two liquid passages.

[0014] The length of the hollow fiber is limited from the point where it can effectively permeate water, and the length of the hollow fiber is 60 to 70 mm up to the end of the U-shaped bottom.
It is normal to use cm. Hollow fiber diameter is 0.2mm~
Those in the 2 mm range are commonly used. Various materials can be used for the hollow fibers, such as cellulose-based, polyolefin-based, polysulfone-based, and polyvinyl alcohol-based materials. Among these, the ones with excellent durability and filtration performance are:
Examples include polyolefin-based porous hollow fibers, and for example, polyethylene-based porous hollow fibers are preferably used.

In forming the hollow fiber filtration module of the present invention, a large number of hollow fibers are bundled and bent into a U-shape.
One end is fixed with a fixing member using an adhesive or the like, and the other end is similarly fixed with a fixing member, and an opening at each end is partitioned to form a liquid chamber. In that case, both liquid chambers can be easily formed by separating them with a partition wall. Although each fixing member could be separate, it would not be easy to manufacture. When fixing the hollow fiber bundle in the fixing member, it is preferable to arrange the hollow fibers uniformly so that they do not come into close contact with each other, and also to keep the bottom ends of the U-shaped hollow fibers as far away from each other as possible. From the viewpoint of preventing clogging, it is preferable to maintain the temperature at

[0016]

[Operation] The case where the hollow fiber filtration module of the present invention is used for filtration will be explained. During the filtration operation shown in FIG. and 10 and taken out from the liquid passage 13. At this time, the switching valve 1 shown in FIG.
5 is closed and cut off from the liquid passage 14, but is not shown in FIG. 1 for the sake of simplicity.

As the filtration operation continues, if colloidal substances accumulate in the hollow fibers of the hollow fiber bundle 2 and cause clogging, the switching valve 11 is closed as shown in FIG.
When the opening is opened and the liquid is sent from the liquid passage 14 to the inside of the hollow fiber from the end 3 of the hollow fiber bundle 2 through the liquid passage 9 and the liquid chamber 6, the liquid flowing inside the hollow fiber to the end 4 is A flow arises,
Colloidal substances accumulated inside the hollow fibers can be removed by being swept away by the liquid flow and flowing out through the liquid chamber 7, liquid passage 10, and liquid passage 13 together with the liquid flow.

The backwashing operation for clogging on the surface of the hollow fibers is carried out in the same manner as in the prior art by feeding the cleaning liquid in the opposite direction from the liquid passage 13 in the state shown in FIG. When cleaning the inside of the hollow fiber in FIG. 2, a filtrate obtained by filtration may be used as the cleaning liquid, or a chemical solution used for chemical cleaning may be used, but it is better to use one with a dilute concentration.

[0019]

[Examples] The present invention will be specifically explained below with reference to Examples. However, the present invention is not limited to this example. Example: The cross-sectional area of one piece is 0.118 mm2, and the length is 1500 m.
5,000 polyethylene hollow fibers of m are bundled together and
Bend it into a letter shape, place a partition between one end and the other end, put them together and bond them with adhesive to make a fixing member with a diameter of 70 mm. One end and the other end of the hollow fiber bundle are trimmed to form each open end, each open end is surrounded by a polyvinyl chloride plate, and the partition is partitioned so that the partition plate serves as a partition wall to form each liquid chamber. A hollow pipe is formed by connecting a polyvinyl chloride pipe with a pipe diameter of 10 mm to each liquid chamber, and connecting both ends of a polyvinyl chloride pipe with a switching valve with the same pipe diameter to the intermediate position of these pipes. A thread filtration module was obtained. Experimental example

[0020] Using the hollow fiber filtration module of the example,
It was immersed in a biological treatment tank using an activated sludge method in which MLSS, which treats organic wastewater with a BOD of 500 ppm, was maintained at 5000 ppm, and filtered by suction from the inside of a hollow fiber to obtain permeated water. The permeation flux at this time is 0.3m3
/m2 ・days, and only backwashing was performed in a timely manner, but as time passed and the permeation flux decreased to 0.2m3 /m2 ・days, backwashing was performed, and after that, the switching valve 11 was closed. The cleaning liquid (filtrate) was passed from one liquid chamber to the other liquid chamber through the hollow fiber for 5 minutes. The permeation flux of this washed product immediately after filtration was 0.3 m3/m2.day.

On the other hand, the same method as above was carried out using a conventional hollow fiber filtration module that had the same length and number of hollow fibers as in the example, no partition wall, and only one liquid chamber. When the treatment was carried out, the permeation flux was 0 if only backwashing was performed.
．． It did not recover from 2m3/m2 ・days.

[0022]

Effects of the Invention In the hollow fiber filtration module of the present invention, one end and the other end of the U-shaped hollow fiber bundle are separated by separate liquid chambers. Since a liquid flow can be passed through the hollow fibers, if clogging or flow obstruction occurs due to the accumulation of colloidal substances inside the hollow fibers, it can be removed by passing a cleaning liquid through the hollow fibers. This makes it possible to maintain a large permeation flux during filtration. Furthermore, during the filtration operation, the filtrate can be sucked from both liquid chambers, so the filtration area of the hollow fibers can be effectively utilized.

[Brief explanation of the drawing]

FIG. 1 is a schematic illustration of an exemplary hollow fiber filtration module of the present invention under conditions used in a filtration operation.

FIG. 2 is a schematic diagram of a hollow fiber filtration module according to an example of the present invention while internal cleaning is being performed.

FIG. 3 is a schematic diagram of a conventional hollow fiber filtration module.

[Explanation of symbols]

1 Hollow fiber filtration module of the present invention 2 Hollow fiber bundle 3 One end of the hollow fiber bundle 4 Other end of hollow fiber bundle 5 Fixed member 6 Liquid chamber 7 Liquid chamber 9 Liquid passage 10 Liquid passage 11 Switching valve 12 Liquid passage 13 Liquid passage

Claims (1)

[Claims] Claim 1: A hollow fiber bundle is formed into a U-shape, one end of the hollow fiber bundle is fixed with a fixing member, an open end of the one end is defined to form a first liquid chamber, and a first liquid chamber is formed by forming a first liquid chamber. A second liquid chamber is formed by fixing the other end with a fixing member and partitioning the open end of the other end, and providing liquid passages connected to the first liquid chamber and the second liquid chamber, respectively. A hollow fiber filtration module characterized in that a switching valve is provided between the liquid passages for communicating with and blocking both liquid passages.