JPS61181507A - Method for washing hollow yarn filter module - Google Patents

Abstract

PURPOSE:To restore the function of a module while the module is arranged in a purifying apparatus by charging water into the water purifier housing a hollow yarn filter module, and oscillating an ultrasonic vibrator. CONSTITUTION:With respect to a water purifier 5 housing a hollow yarn filter module with reduced filtration capacity, an ultrasonic vibrator 6 is brought into contact with the wall surface of the water purifier, or the oscillating end of the ultrasonic vibrator is inserted into the water purifier. Then the ultrasonic vibrator 6 is oscillated to carry out washing. When the ultrasonic vibrator is oscillated, the inside of the water purifier must be filled with water. Treated water contg. fine colloidal materials and metallic ions or purified water for washing can be used as the water to be filled into the purifier.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for cleaning a hollow fiber filtration module for a water purifier, and more specifically, a method for cleaning a hollow fiber filtration module for a water purifier. The present invention relates to a method for cleaning a filtration module while it is placed inside a water purifier.

``Conventional technology'' Conventionally, ultrafiltration filters are typically used as water purifiers for removing iron rust and suspended matter in water, but the filters tend to become clogged. Ta. Furthermore, there is a limit to the size of fine particles that can be removed by such water purifiers, and metal ions cannot be removed.

For example, recovered water recovered from boiling water nuclear power generation turbines contains impurities such as approximately 15 PPb of iron ions and fine colloids, but this is recovered as is and recycled as condensate to the reactor. If this occurs, the impurities will coagulate and adhere in the furnace, leading to a decrease in power generation efficiency. Therefore, it is necessary to purify and condense the impurities so that the amount of these impurities is at least about 0.5 PPb or less.

As mentioned above, when it is necessary to remove extremely fine colloidal substances, metal ions, etc., which are impurities contained in recovered water, with high efficiency, reverse osmosis membranes are used in the general water treatment field. The water purification device used is being used suitably. However, in the case of reverse osmosis membrane equipment, the pressure required for filtration tends to be very high, so the equipment needs to be large, and systems that need to be closed systems, such as the treatment of water recovered from nuclear power generation, are required. It was unsuitable for filtration.

On the other hand, porous hollow fiber filtration membranes have an excellent water purification function, but they have been applied to fields where it is necessary to filter a large amount of water that contains relatively large amounts of fine colloidal substances and metal ions. In this case, the filtration membrane is easily clogged, and it is difficult to remove the clog and restore its function, so it has not been used much in the past.

Conventionally, a so-called backwash method, in which a water flow is run in the opposite direction to that used during filtration, has been considered as a method for restoring the function of a clogged hollow fiber filtration membrane. In addition, at the same time as this backwashing, air bubbles generated by blowing gas from below the module are applied to the hollow fiber filtration membrane, and physical vibration is applied to the hollow fiber filtration membrane, causing the bubbles to coagulate and adhere to the surface of the hollow fiber filtration membrane. Studies are also underway on methods for shaking off colloidal substances.

[Problems to be Solved by the Invention] However, even if the filtration function of the hollow fiber filtration module is regenerated by the above-mentioned backwashing method or bubble vibration method, there is a limit to the degree of functional recovery with the backwashing method. Ta. In addition, in the bubble vibration method, the bubbles often do not hit the entire surface of the hollow fiber filtration membrane well, and as a result, sufficient function recovery may not be possible, or the hollow fiber filtration membrane may not be able to fully recover due to the turbulence of the liquid caused by the bubbles. Odors can occur between the membranes, resulting in a decline in filtration function, and in extreme cases, entanglement between the hollow fibers can damage a portion of the hollow fiber filtration membrane, causing it to no longer function as a filtration membrane. Sometimes it happened.

On the other hand, a cleaning method using ultrasonic waves is conventionally known as a cleaning method for removing oil films and solid matter adhering to articles formed from various rigid bodies. However, cleaning flexible articles such as textiles using ultrasonic waves has not been considered efficient. However, the present inventors have investigated that hollow fiber filtration membranes, especially microporous hollow fiber filtration membranes, are not flexible enough to remove fine colloidal substances that block the micropores of the membranes. It has been found that these colloidal substances can be removed extremely efficiently despite the fact that they exhibit

An object of the present invention is to provide a method for cleaning a hollow fiber filtration module that can easily and efficiently perform a function recovery process on the hollow fiber filtration module to restore its initial performance.

Another object of the present invention is a method for cleaning a hollow fiber filtration module that can easily perform a cleaning operation to restore the function of a clogged filtration membrane while the filtration module remains installed in a purification device. Our goal is to provide the following.

[Means for Solving the Problems] That is, the method for cleaning a hollow fiber filtration module of the present invention is a method for cleaning a hollow fiber filtration module that includes a large number of hollow fiber filtration membranes that are bundled and fixed. The method includes the step of causing the ultrasonic oscillator to oscillate after the ultrasonic oscillator is brought into contact with a wall surface of the water purifier or inserted into the water purifier that is housed and filled with water. It is characterized by

[Preferred mode for carrying out the invention] The hollow fiber filtration module to which the first cleaning method of the present invention is applied basically requires support for the entire module when installing the module in a water purifier. an annular member that functions as a support member for the purpose of cleaning, and a ring member that functions as a partition member between the water to be purified and the purified water in order to fix the end of the hollow fiber filtration membrane and function as a filtration membrane; It is composed of a fixing member disposed on the inner surface of the annular member, and a hollow fiber filtration membrane that is focused and fixed by the fixing member while keeping each open end open. A member may be attached.

The hollow fiber filtration module cleaning method of the present invention applies an ultrasonic oscillator to the wall surface of a water purifier that houses a hollow fiber filtration module that has been subjected to filtration for a predetermined period and whose filtration processing capacity has decreased. This is carried out by touching the ultrasonic oscillator or inserting the oscillating end of the ultrasonic oscillator into the water purifier and causing the ultrasonic oscillator to oscillate. The inside of the water purifier is filled with water when the ultrasonic oscillator oscillates, but this filled water may be treated water containing fine colloids, metal ions, etc. Purified water may also be used.

The cleaning method of the present invention is carried out by oscillating an ultrasonic oscillator and applying the ultrasonic waves to the hollow fiber filtration membrane in the module using the water filled in the water purifier as a medium. Therefore, if ultrasonic waves can be applied to the water filled in the water purifier, the oscillation end of the ultrasonic oscillator will be.

It may be placed inside the water purifier or may be placed in contact with the outer surface of the water purifier container. Of course, such an ultrasonic oscillator may be placed in advance on the water purifier You can leave it there.

The cleaning method of the present invention is characterized by having a step of oscillating an ultrasonic oscillator with a hollow fiber filtration module installed in a water purifier and applying ultrasonic waves to the hollow fiber membrane in the module. Of course, the conventional backwashing method can also be performed at the same time as this ultrasonic oscillation, and the combination of these two cleaning methods can shorten the cleaning time and more effectively restore the original performance. This is a preferred embodiment in which it is possible.

The hollow fiber filtration module to be treated by the cleaning method of the present invention has the above-mentioned configuration, and the hollow fiber membranes constituting the hollow fiber filtration module include cellulose, polyolefin, polysulfone, Polyvinyl alcohol-based.

Hollow fiber filtration membranes made of various materials such as PMMA can be used. However, polyolefin-based porous hollow fiber membranes have excellent durability, excellent filtration performance, and can be effectively restored by the cleaning method of the present invention. Examples include polyethylene hollow fiber membranes (polyethylene hollow fiber EHF, trade name, manufactured by Mitsubishi Rayon ■).

In the cleaning method of the present invention. The ultrasonic output from the ultrasonic oscillator is 0.015 to 0.2 W /
About cm3 is appropriate. If the ultrasonic output is less than the above value, the cleaning effect of the hollow fiber filtration module will not be sufficiently demonstrated, and if the ultrasonic output exceeds the above value, 1
For example, an ultrasonic output of 0.05 to 0.00 is undesirable because it has an adverse effect on the adhesive force between the annular member and the fixing member of the hollow fiber filtration module, or on the installation and fixing part of the water purifier. I
It is more preferable that W/c is about 113.

[Effect of the Invention 1] According to the method for cleaning a hollow fiber filtration module of the present invention, cleaning can be performed to recover the function of a hollow fiber filtration membrane that has become clogged while the module is installed in a purification device. Easy to operate.

In addition, the function recovery process can be performed to a point close to the initial performance of the module.

[Embodiments of the invention]

Hereinafter, the method of the present invention will be explained in more detail based on examples.

Comparative Example 1 and Example 1.2 Polyethylene hollow fiber filtration Il! 111 (polyethylene hollow fiber, EHF-31100, product name Mitsubishi Rayon■
! ml is concentrated and fixed in a U-shape using a potting material 4 while keeping the open end of the hollow fiber filtration membrane open on a module housing material consisting of an annular member 2 with an inner diameter of a5-■φ and a hollow fiber support member 3. Hollow fiber filtration module (
Thread length of hollow fiber filtration membrane: 25c■, review surface m: 0.
3rn') was incorporated into a stainless steel water purification container 5 as shown in FIG. 1, and purification treatment was carried out. Water purification container 5
An ultrasonic oscillator 6 with a maximum output of 600 W is installed on the outer surface of the container at the center of the hollow fiber bundle in the longitudinal direction.
was brought into contact with the

A dispersion containing approximately 10 geg/j of suspended solids mainly composed of iron oxide and iron hydroxide was supplied as a filtration stock solution at a flow rate of 17/win, and was continuously purified using this water purifier.

When the filtration operation differential pressure reached 3.0 kg/cs2, the purification process was stopped, and the function regeneration process was carried out using the following three methods.

■Open the air release valve 7 and supply air from the lower filtration solution supply port 8 to 0.51. /sin for 10 minutes (Comparative Example 1).

■The ultrasonic oscillator 6 was oscillated for 10 minutes at an output of 100W (
Example 1) ②The above operations ① and ② were carried out simultaneously. (Example 2
) Next, once the water containing the concentrated suspended solids in the water purifier is drained out, and the same filtered stock solution is poured again for 14 minutes. Supplied with 77B,
The initial filtration operating pressure was measured. The results are shown in Table 1.

Table 1 Comparative Example 2 and Example 3.4 As a hollow fiber filtration module, the thread length of the hollow fiber filtration membrane is B.
oas, a large-scale structure similar to that of Example 1 with a film formation area of 10 rn' was used, the filtration stock solution was supplied at tm'har, and the ultrasonic oscillator 6 was used to supply the filtration stock solution instead of the outer surface of the container. Purification treatment was carried out in the same manner as in Example 1, except that it was fixed inside the container near the mouth, that is, below the module.

When the filtration operation differential pressure reached 3.0 kg/cs2, the purification treatment was stopped and the following functional regeneration treatments were carried out, and then the initial filtration operation differential pressure was measured in the same manner as in Example 1. .

(2) Air was supplied at 0.5 NA/win for 10 minutes (Comparative Example 2).

■The ultrasonic oscillator 6 was oscillated for 20 minutes at the output eoow (
Example 3) ② The above operations ① and ② were carried out simultaneously. (Example 4
) The results are shown in Table 2.

Table 2

[Brief explanation of drawings]

FIG. 1 is a schematic cross-sectional view showing an embodiment of the hollow fiber filtration module cleaning method of the present invention. 1: Hollow fiber filtration membrane 2: Annular member 3: Hollow fiber support member 4: Botting material 5: Water purification container 6: Ultrasonic oscillator 7: Air vent valve 8: i11 stock solution supply port Patent applicant Mitsubishi Rayon Co., Ltd. Company ↑ Figure 1

Claims (1)

[Claims] 1) In a method for cleaning a hollow fiber filtration module equipped with a large number of hollow fiber filtration membranes that are focused and fixed, an ultrasonic oscillator is applied to a water purifier that houses the module and is filled with water.
A method for cleaning a hollow fiber filtration module, comprising the step of causing the ultrasonic oscillator to oscillate after contacting a wall surface of the water purifier or inserting the ultrasonic oscillator into the water purifier.