JPH0667457B2 - Hollow fiber membrane filtration device - Google Patents

Description

The present invention relates to a hollow fiber membrane filtering device using a hollow fiber membrane module as a filtering material, and more particularly to a supporting member having a hollow lower end of a protective cylinder. The present invention relates to a hollow fiber membrane filtration device that can be fixed by means of the above to prevent the accumulation of clad and the like to reduce the exposure of workers and improve the backwash efficiency.

(Prior Art) Generally, in nuclear power plants, as a measure to reduce radioactivity, the generation of corrosion products is suppressed and its removal is carried out. For example, radioactive waste liquid or suspension water present in the condensate of the reactor condensate water supply system is used. A filter device is used to separate and remove the suspended matter.

As the filter device, a filter device using a precoat filter such as a powder ion exchange resin, a flat membrane filter such as a filter paper, a filter cloth, a membrane filter, or a hollow tube type filter such as a sintered metal or a ceramic is conventionally used. Although a filter or the like has been used, in recent years, a hollow fiber membrane filtering device using a hollow fiber membrane module as a filtering material has become widespread.

This hollow fiber membrane is a hollow fiber membrane with an outer diameter of about 0.3 to 3 mm and a large number of fine permeation holes. It is also capable of capturing suspensions with a particle size of 0.1 μm or less, and per unit volume. Because of its large filtration area and excellent pressure resistance, it is widely used as a filter material for ultrafiltration and reverse osmosis filtration in the fields of electronics industry, medicine, wastewater treatment and the like.

FIG. 5 is a sectional view showing an example of this hollow fiber membrane filtering device. In this hollow fiber membrane filtration device, a closed container 1 is divided into a filtration chamber 3 and a treatment liquid chamber 4 by a tube plate 2, and a plurality of hollow fiber membrane modules 5a are vertically installed in the filtration chamber 3 in multiple stages. ing. Each hollow fiber membrane 6 is attached to the module fixing portion 7
It is fixed to the tube sheet 2 through the tube sheet 2 which is a closed container 1.
Peripheral flange 8 attached to the edges of the body 1A and the lid 1B of
It is sandwiched and fixed by 9 and 9.

The hollow fiber membrane module 5a is generally a fibrous hollow fiber membrane 6
Has a module structure in which a large number of them are bundled in a linear or U-shape and the ends are fixed by a resin or the like, and the portion fixed by the resin or the like is the module fixing portion 7.

In the hollow fiber membrane filtration device shown in this example, the sixth
As shown in the figure, hollow fiber membranes 6 are bundled in a straight line and hollow fiber membrane modules 5a having fixed end portions are connected in series in three stages. The module fixing portions 7 are connected by a connecting tool 23, and the upper end portion is further connected. The grip 22 is attached to the base, and the closure 24 is connected to the lower end to form an integral hollow fiber membrane module structure 5, and the grip 22 is fitted into the mounting hole formed in the tube sheet 2. Then, the hollow fiber membrane module structure 5 is fixed. Here, the connecting tool 23 connects the hollow fiber membrane modules 5a to each other, and at the same time, the water collecting pipe 11 arranged at the center of the hollow fiber membrane modules 5a.
Has a function of communicating over the entire length of the structure 5.

As shown in FIG. 5, the hollow fiber membrane module structure 5 is housed in a cylindrical protective cylinder 15 that is fixed to the lower surface of the tube sheet 2 and hangs down inside the filtration chamber 3.

As shown in FIG. 7, the side wall of the protection cylinder 15 is recessed inward at a predetermined position in the axial direction of the protection cylinder 15, that is, at a portion facing the module fixing portion 7 of the housed hollow fiber membrane module structure 5. A plurality of protrusions 19 are formed in the circumferential direction. The protrusion 19 suppresses the vibration of the hollow fiber membrane module structure 5 during the filtration operation and the backwash operation by pressing and fixing the module fixing portion 7.

A rectifying tube bundle 20 is provided at the lowermost end of the protective cylinder 15. This rectifying tube 20 is a short rectifying tube as shown in FIG.
A large number of 21 are bundled with their central axes parallel to each other, and are attached to the lowermost end of the protective cylinder 15. The rectifying tube bundle 20 functions as a rectifying mechanism for causing the supply liquid introduced from the supply liquid inlet nozzle 10 provided at the bottom of the filtration chamber 3 to uniformly flow into each protection cylinder 15.

Then, the waste liquid generated from the nuclear power plant is introduced into the filtration chamber 3 from the supply liquid inlet nozzle 10, and when passing through the surface of each hollow fiber membrane 6, foreign matters such as clad are separated and removed, and filtered. After passing through the hollow portion of the hollow fiber membrane 6 into the water collecting pipe 11 provided at the center of the bundle of each hollow fiber membrane module 5, the treated liquid flows into the treatment liquid chamber 4 via the tube plate 2. Then, it is transferred to the outside of the system through the processing liquid outlet nozzle 12.

By the way, an air layer 13 is usually formed in the upper part of the filtration chamber 3 after a predetermined volume of the supply liquid is filtered. This air layer 13 is formed because minute air bubbles in water, air bubbles adhering to the inner surface of a pipe or the surface of equipment, etc. are gradually accumulated at the upper part due to long-term operation. Has
A valve (not shown) downstream of the nozzle of the vent 14 was opened to discharge the air together with the supply liquid to the waste treatment system. The vent 14 is also used in a backwash operation for removing the clad and the like adhering to the surface of the hollow fiber membrane 6 when the permeation pressure loss increases due to clogging of the hollow fiber membrane 6.

At the time of the backwashing operation, the backwashing air is introduced from the air inlet nozzle 16 arranged at the bottom of the filtration chamber 3, the air is blown out as air bubbles from the air blowing pipe 17, and the hollow fiber membrane module 5a is caused by the impact force of the rising air bubbles. The hollow fiber membrane 6 is vibrated, and the clad and the like adhering to the surface of the hollow fiber membrane is peeled off to regenerate the filtration function of the hollow fiber membrane. The backwash water used for the backwash is transferred from the backwash water outlet nozzle 18 provided at the bottom of the filtration chamber 3 to the wastewater treatment facility.

(Problems to be Solved by the Invention) However, in the conventional hollow fiber membrane filtration device, the protection tube 15 is not fixed, but only the protection tube 15 and the tube sheet 2 are hung vertically from the tube sheet 2. The mounting part of is solid, its workability is poor, and a large number of manufacturing steps are required. Also, when fixing the protective cylinder 15, make holes in the plate in the same number as the protective cylinder 15, and then pass the protective cylinder 15 through the holes to secure it.
A hooking mechanism such as a notch or a hook was previously attached to the lower end of the, and fixed by this.

However, these methods increase the number of parts, require a great deal of labor for manufacturing and assembling work, and increase the weight of the apparatus.

In addition, since the lower end of the protective cylinder 15 fixed by the fixing portion 26 and the like has a complicated shape, there is a problem that the clad or the like is easily deposited during backwashing and the radiation exposure dose is increased.

Further, at the time of backwashing, air is blown out as air bubbles from the air blowing pipe 17 provided at the lower part of the protection cylinder 15, and the hollow fiber membrane module 5a
Is vibrated to drop the clad or the like deposited on the surface of the hollow fiber membrane 6 by the impact of bubbles. However, at this time the protective cylinder 15
Since the lowermost end of the is not fixed, air bubbles from the air blowing pipe 17 do not evenly enter the protective cylinder 15, the vibration width of the surface of the hollow fiber membrane 6 is small, and the backwashing action does not proceed effectively. There was a problem.

The present invention has been made to solve the above-mentioned problems, in which the lower end of the protective cylinder is fixed by a hollow supporting member to reduce the manufacturing man-hour and improve the backwash backwash rate of the hollow fiber membrane at the time of backwashing. It is an object of the present invention to provide a hollow fiber membrane filtration device.

[Structure of Invention]

(Means for Solving the Problem) The present invention has a tube plate that divides the inside of a closed container into a lower filtration chamber and an upper processing liquid chamber, and a protective tube that is hung from the tube plate into the filtration chamber. In a hollow fiber membrane filtration device having a hollow fiber membrane module structure housed in the protective cylinder and suspended from the tube sheet, a swing prevention mechanism for preventing swing of the protective cylinder is provided at a lower end of the protective cylinder. The swing prevention mechanism is provided in the opening and is composed of a hollow cylindrical restraining support member that connects the protection cylinders to each other, and a plurality of hollow short rectifying tubes are arranged in parallel with their central axes in the lower part of the protection cylinder. It is characterized by having a rectifying mechanism that is bundled together.

(Operation) According to the hollow fiber membrane filtration device having the above-mentioned configuration, the protection cylinder and the tube sheet can be easily attached, and when the protection cylinder is fixed, the accumulation of the clad etc. at the lower end of the protection cylinder is prevented, and the radiation exposure of the worker The amount can be significantly reduced.

Also, since the lower end of the protective tube is fixed and does not move, backwash air bubbles during backwash enter each protective tube evenly, and all hollow fiber membrane modules evenly peel off the deposited clad on the membrane surface. Therefore, it is possible to carry out effective backwashing without unevenness in backwashing.

(Embodiment) An embodiment of the present invention will be described below with reference to FIGS. 1 and 2. FIG. 1 is a cross-sectional view showing an embodiment of the hollow fiber membrane filtration device according to the present invention, the same reference numerals are given to the same component parts as in the conventional example shown in FIG. 5, and the detailed description thereof will be omitted. .

In FIG. 1, the closed container 1 is divided by a tube plate 2 into a lower filtration chamber 3 and an upper processing liquid chamber 4. The upper end of a protective cylinder 15 is fixed to the lower surface of the tube plate 2, and the protective cylinder 15 is suspended in the filtration chamber 3. The hollow fiber membrane module structure 5 is housed in the protective cylinder 15, and the module fixing portion 7 at the upper end of the hollow fiber membrane module structure 5 is fitted and fixed in a mounting hole provided in the tube sheet 2.

The protection cylinder 15 is made of a straight pipe material having a projection on the side wall surface, and a swing prevention mechanism 25 for preventing the protection cylinder 15 from swinging is provided at the lowermost end thereof.

For details of the swing prevention mechanism 25, as shown in FIG.
A support member 25a for restraint is arranged around the protective cylinder 15 at the lower end of and is fixed to the adjacent protective cylinders 15 by welding, adhesion, crimping, or the like. The rectifying tube bundle 20 in the protective cylinder 15 is omitted for simplification of the drawing.

The restraint support member 25a is hollow and prevents the clad or the like from being deposited on the restraint support member 25a during backwashing.

As an example of the restraint support member 25a, a thin pipe material having a length of 10 to 70 mm and a thickness of 1.5 mm is used. The outer diameter of the pipe material varies depending on the outer diameter of the protection cylinder 15 and the arrangement pitch of the hollow fiber membrane module structures 5, that is, the arrangement pitch of the protection cylinders 15. Regardless of the outer diameter and the arrangement pitch, it is necessary to select the pipe outer diameter that fits the clearance between the protection cylinders 15.

Next, the operation of this will be described.

The liquid to be treated is introduced from the lower end of the protective cylinder 15 as shown by the thick arrow, reaches the hollow fiber membrane 6 through the flow regulating tube bundle 20, and reaches the hollow fiber membrane 6.
The treated water filtered on the surface of the hollow fiber flows downward in the hollow portion of the hollow fiber membrane 6 as indicated by a thin arrow, and the module fixing portion 7
After passing through the inside, it is collected in the central portion of the module 5 by a closing tool similar to the closing tool 24 shown in FIG. 6 above, and the water collecting pipe 11 rises and flows into the processing liquid chamber 4.

At the time of backwashing, bubbles for backwashing are introduced into the lower end opening of the protective cylinder 15, but since the protective cylinder 15 is fixed at the lower end,
Positional variation of the lower end in the radial direction is prevented. Therefore, at the time of backwashing, air bubbles for backwashing from the air blowing pipe 17 uniformly enter the protective cylinder 15, and only the hollow fiber membrane 6 vibrates greatly by the air bubbles for backwashing, and the clad and the like adhered and deposited on the membrane surface are removed. It can be effectively removed and the backwash efficiency can be improved.

Protective cylinder 15 with a porous fixing part such as a conventional disk
Since the shape is simplified compared to fixing the lower end, the number of manufacturing steps is significantly reduced, and the accumulation of clad etc. on the fixing plate is prevented, and the radiation exposure dose of the worker is greatly reduced. be able to.

Next, another embodiment of the present invention will be described with reference to FIG. Note that, for simplification of the drawing, the flow straightening tube bundle 20 in the protective cylinder 15 is omitted.

The rocking prevention mechanism of the protection cylinder used in the hollow fiber membrane filtration device according to the present embodiment has a hollow triangular prism 25 in the gap between the protection cylinders 15.
b is arranged and fixed to each protection cylinder 15.

Next, still another embodiment of the present invention will be described with reference to FIG.

The rocking prevention mechanism used in the hollow fiber membrane filtering apparatus according to this embodiment is not limited to the multi-stage hollow fiber membrane filtering apparatus as shown in FIG. 2 but also the bundled end of the hollow fiber membranes 6 as shown in FIG. It can also be used in a hollow fiber membrane filtration device of a type in which the part is only on the side of the tube sheet 2.

〔The invention's effect〕

As described above, according to the hollow fiber membrane filtration device of the present invention, the hollow supporting member is arranged at the end of the protective cylinder, and the plurality of positions on the outer periphery of the protective cylinder are fixed. The structure is simplified, the number of parts and the number of manufacturing steps are significantly reduced, and the accumulation of the clad on the protective cylinder fixing portion is prevented, so that the radiation dose of the worker can be significantly reduced.

Also, during backwashing, since the lower end of the protective cylinder is fixed, backwashing air bubbles enter the protective cylinder evenly, and only the hollow fiber membrane vibrates greatly due to the backwashing air, and the clad, etc. adhered to the membrane surface. Can be effectively removed, and the backwash efficiency can be significantly improved.

[Brief description of drawings]

FIG. 1 is an enlarged cross-sectional view showing an essential part of an embodiment of the present invention, which is viewed from the line II-II in FIG. 2, and FIG. 2 is a hollow fiber membrane filtration to which FIG. 1 is applied. FIG. 3 is a sectional view showing an example of an apparatus, FIG. 3 is an enlarged sectional view showing an essential part of another embodiment of the present invention, and FIG. 4 is another example of a hollow fiber membrane filtering apparatus to which FIG. 1 is applied. 5 is a sectional view showing a conventional hollow fiber membrane filtration device, FIG. 6 is a sectional view showing the hollow fiber membrane module structure shown in FIG. 5, and FIG. 7 is a sectional view taken along line VIII- of FIG. FIG. 8 is a sectional view taken along line VIII, and FIG. 8 is a sectional view taken along line IX-IX in FIG. 1 ... Airtight container, 2 ... Tube plate 3 ... Filtration chamber, 4 ... Treatment liquid chamber 5 ... Hollow fiber membrane module structure 15 ... Protective cylinder, 25 ... Rocking prevention mechanism 25a, 25b. Support member

Claims (1)

[Claims] 1. A tube plate for partitioning the inside of a closed container into a lower filtration chamber and an upper processing liquid chamber, a protective cylinder hung from the tubular plate into the filtration chamber, and a protective cylinder housed in the protective cylinder. In a hollow fiber membrane filtering device having a hollow fiber membrane module structure suspended from the tube sheet, a rocking prevention mechanism for preventing rocking of the protection cylinder is provided in a lower end opening of the protection cylinder, and rocks. The prevention mechanism is composed of a hollow cylindrical restraining support member that connects the protection cylinders to each other, and a protection mechanism is provided at the lower part of the protection cylinder with a rectification mechanism in which a plurality of hollow short rectification tubes are bundled with their central axes parallel to each other. A hollow fiber membrane filtration device characterized in that