JPH0537328U - Hollow fiber membrane module - Google Patents

Abstract

(57) [Summary] (Correction) [Purpose] To provide a hollow module that can be effectively cleaned by backwashing with air, with almost no accumulation of dirt on the membrane surface and adhesion between membranes, for use in wastewater treatment and the like. A hollow fiber membrane module produced by uniformly dispersing and filling a hydrophilic porous hollow fiber membrane 1 and a hydrophobic porous hollow fiber membrane 2.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a novel hollow fiber membrane module suitable for use in filtering a liquid polluted with an organic substance while using backwashing together.

[0002]

[Prior Art]

 In various applications such as secondary treatment, tertiary treatment in sewage treatment plants and solid-liquid separation in septic tanks, the use of separation membranes has been studied in various ways. However, most of the modules used there are those that were used for filtering pure water or tap water in the past. In most cases, even if the improvements were made, the filling rate and filling form of the hollow fiber membranes were changed.

[0003]

[Problems to be solved by the device]

 When highly polluted water (eg SS ≧ 50ppm, TOC ≧ 100ppm) is filtered using the above module, organic substances, etc. will adhere to the film surface during long-term use with backwashing. It causes blockage of fine pores on the surface of the hollow fiber and adhesion phenomenon between the hollow fibers. Therefore, there was a problem that the permeation flow rate per module was significantly reduced. The present invention has been made to solve the above-mentioned conventional drawbacks.

[0004]

[Means for Solving the Problems]

 That is, the gist of the present invention is produced by uniformly dispersing and filling a hydrophilic porous hollow fiber membrane A and a hydrophobic porous hollow fiber membrane B in a weight ratio of A: B = 1: 0.2 to 2. Located in the hollow fiber membrane module.

Specifically, as shown in FIG. 1, a hydrophilic porous hollow fiber membrane knitted in a knitted form and a hydrophobic multi-porous hollow fiber membrane are layered in a sushi roll shape to form a module. When the hollow fiber membrane is used as the weft yarn, the warp yarn can be a yarn that is commonly used as a warp yarn for knitted fabrics, but a non-stiff yarn is used to prevent damage to the hollow fiber membrane during knitting and handling. I like to use it. In the present invention, it is sufficient if they are evenly distributed and almost evenly distributed. The module is a module in which hydrophilic porous hollow fiber membranes and hydrophobic porous hollow fiber membranes are alternately present toward the center.

Since the hydrophobic hollow fiber membrane is impermeable to water during filtration, almost no accumulation of dirt is observed on the surface. Therefore, the hydrophobic hollow fiber membrane acts as a spacer for preventing the adhesion between the hydrophilic hollow fiber membranes, and the reduction of the filtration area (= the reduction of the filtration flow rate) due to the adhesion between the hydrophilic hollow fiber membranes can be reduced. It does not matter whether the filtration method is full-scale filtration or cross-flow filtration.

When backwashing, air is aerated from the secondary side to release air from the surface of the hydrophobic hollow fiber membrane. Due to the bubbling effect of the released air, dirt accumulated on the surface of the hydrophilic hollow fiber membranes can be removed and the adhesion between the hollow fiber membranes can be peeled off. The air flow rate is not particularly limited, but 1000 Nl / m ² · min or more is desirable.

As the material forming the hollow fiber membrane used in the present invention, known materials such as polyethylene, polypropylene and polysulfone can be used. The pore diameter, porosity, film thickness, outer diameter, etc. are not particularly limited.

A surfactant or a hydrophilic polymer can be used as a hydrophilizing agent for hydrophilizing a hydrophobic hollow fiber membrane made of a hydrophobic material. A poorly water-soluble hydrophilic agent is especially desirable. Examples of the hydrophilizing agent include hydroxyethyl methacrylate, propylene glycol monostearate, polyvinylpyrrolidone, a copolymer of diacetone acrylamide and a crosslinking monomer, and a saponified product of ethylene-vinyl acetate copolymer (ethylene-vinyl alcohol system). Copolymers) and the like. Of course, a hollow fiber membrane made of a hydrophilic polymer can also be used.

For example, the following hollow fiber membrane is used as a hydrophobic hollow fiber membrane, and a saponification product of ethylene-vinyl acetate copolymer (ethylene-polyvinyl alcohol copolymer) or diacetone acrylamide and a crosslinking monomer are used. It is also possible to use a hydrophilic hollow fiber membrane in which the copolymer from (3) is retained on the membrane surface.

A porous hollow fiber made of polyethylene, wherein strip-shaped micropores formed by being surrounded by microfibrils arranged in the fiber length direction and a knot portion made of a stack lamella are formed in the hollow fiber. It has a laminated structure in which the wall surface communicates with the outer wall surface, the average pore diameter of the micropores measured by a mercury porosimeter is more than 2 μm and 10 μm or less, the porosity is 75% to 95%, and the air permeation amount is 8 × 10 ⁵ l / m ² · hr · 0.5 atm or more large-pore porous polyethylene hollow fiber membrane

A porous hollow fiber made of polypropylene, in which strip-shaped micropores formed by being surrounded by microfibrils arranged in the fiber length direction and a knotted part made of a stack lamella are formed on the inner wall surface of the hollow fiber. It has a layered structure that is more in communication with the outer wall surface, the average pore size of the micropores measured by mercury porosimeter is more than 1 μm and 10 μm or less, the porosity is 70% to 95%, and the air permeation amount is 4 × 10 ⁵ l / m ² · hr · 0.5 atm or more large-pore porous polypropylene hollow fiber membrane

As the potting agent used in the present invention, known materials such as urethane type and epoxy type can be used. As the material of the housing, known materials such as polycarbonate, acrylic, polysulfone and polypropylene can be used.

[0014]

【effect】

 The hollow fiber membrane module according to the present invention is particularly effective in preventing a decrease in flow rate due to adhesion between hollow fibers in filtering highly polluted water. Therefore, it is suitably used in the fields of wastewater treatment, river water filtration, industrial water filtration and the like.

[Brief description of drawings]

FIG. 1 is a diagram in which two kinds of hydrophilic and hydrophobic knitted hollow fiber membranes are stacked and a schematic view of a state in which the knitted hollow fiber membranes are sushi roll-shaped and potted.

FIG. 2 is a schematic sectional view showing an example of the module of the present invention.

[Explanation of symbols]

 1 Knitted hydrophilic hollow fiber membrane 2 Knitted hydrophobic hollow fiber membrane 3 Potting part 4 Mixture of hydrophilic hollow fiber membrane and hydrophobic hollow fiber membrane 5 Outer cylinder 6 Liquid introduction part 7 Liquid discharge part 8 Circulation during cross-flow filtration Liquid outlet 9 Air inlet during backwash

Claims (3)

[Scope of utility model registration request] 1. A hollow produced by uniformly dispersing and filling a hydrophilic porous hollow fiber membrane A and a hydrophobic porous hollow fiber membrane B in a weight ratio of A: B = 1: 0.2 to 2. Thread film module. 2. The hollow fiber membrane module according to claim 1, wherein the knitted hydrophilic porous hollow fiber membrane and the hydrophobic porous hollow fiber membrane are superposed and formed into a sushi roll shape. 3. The hollow fiber membrane module according to claim 1, wherein air is sent from the filtrate side during backwashing to generate bubbles from the surface of the hydrophobic hollow fiber for backwashing.