JPH02191531A - Filter module by hollow-fiber membrane - Google Patents

Abstract

PURPOSE:To efficiently backwash the hollow-fiber membrane by stripping a clad from the membrane by the cleaning water permeating through the cylindrical wall of the membrane from the inner periphery to outer periphery and the ascending bubbles in contact with the surface of the wall. CONSTITUTION:An inner cylinder 12 with its lower part protruding downward from the lower end of a vertical protective cylinder 11 is installed in the vertical protective cylinder 11 in which raw water is flowed. The upper and lower parts of a cylindrical space 13 formed by the inner cylinder 12 of the protective cylinder 11 and the outer periphery of the inner cylinder 12 are closed by the upper wall 14 and the lower wall 15. Many hollow-fiber membranes 16 are vertically arranged in the cylindrical space 13, the upper end of each membrane 16 pieces the upper wall 14 and is opened on the upper wall 14, and the lower end is embedded in the lower wall 15 and closed. A chamber 17 for collecting treated water communicating with the inner cylinder 12 is provided on the upper wall 14, a vertical air-passage hole 18 is bored through the lower wall 15, and an air chamber 19 with the lower part opened is arranged under the lower wall 15.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a filtration module using a hollow fiber membrane for use in a precoat type filtration device.

<Conventional technology> A hollow fiber membrane type filtration device using a filtration module using a hollow fiber membrane supplies raw water in an upward flow into a filtration tower, passes through the cylindrical membrane wall of the hollow fiber membrane, and enters the hollow part. The treated water obtained is taken out from the top of the filtration tower. In contrast, in a precoat type filtration device using a hollow element having a precoat layer with fine particles of ion exchange resin attached to the surface, raw water is supplied into the filtration tower in an upward flow, passes through the precoat layer on the surface, and passes through the hollow part of the element. The treated water obtained is taken out from the bottom of the filtration tower, contrary to the hollow fiber membrane type.

In either filtration device, if the cylindrical membrane wall of the hollow fiber membrane or the precoat layer of the hollow element becomes clogged with captured crud and the pressure loss increases, backwashing is performed with air and washing water to remove the crud. However, in this case, only the trapped crud is removed from the hollow fiber membrane by backwashing, whereas in the hollow fiber membrane, along with the crud,
Since the ion exchange resin constituting the precoat layer is also removed, a much larger amount of waste is produced compared to hollow fiber membranes.

Moreover, before restarting filtration, it is necessary to newly provide a precoat layer on the surface of the hollow element.

For this reason, a filtration module has been proposed for use with conventional pre-coat type filtration equipment, which uses a hollow fiber membrane that generates less waste during backwashing and can restart filtration immediately after backwashing. .

<Problems to be Solved by the Invention> In the above-mentioned known example, raw water supplied in an upward flow into a filtration tower passes through a cylindrical membrane wall of a hollow fiber membrane, and the treated water obtained in the hollow part is collected. It only discloses the principle of how to extract the material from the bottom of the filtration tower, but does not provide any specific details such as how to backwash the hollow fiber membrane with air and washing water if the surface of the hollow fiber membrane becomes clogged. Therefore, it is impossible to put S into practical use as it is.

(Means for Solving the Problems) Therefore, the present invention has been developed for the purpose of providing a specific filtration module that can be put to practical use, and is a filtration module using a hollow fiber membrane according to claim 1. teeth,
An inner cylinder whose lower part protrudes downward from the lower end of the protection cylinder is disposed in the vertical direction inside the protection cylinder in the vertical direction through which the raw water flows,
A cylindrical space formed by the inner periphery of the protection cylinder and the outer periphery of the inner cylinder is closed at the top and bottom by an upper end wall, a lower end wall, and an end wall, and a large number of hollow fiber membranes are installed inside the cylindrical space. arranged vertically,
The upper end of each hollow fiber membrane penetrates the upper end wall and opens onto the upper end wall, and the lower end is buried and closed in the lower end wall. A liquid collecting chamber is provided, a ventilation hole penetrating the lower end wall in the vertical direction is provided, and an air chamber opened downward is provided below the lower end wall.

Further, the filtration module using hollow fiber membranes according to claim 2,
An inner cylinder whose upper part projects upward from the upper end of the protection cylinder is disposed in the vertical direction inside the protection cylinder in the vertical direction through which the raw water flows,
The upper and lower ends of the cylindrical space formed by the inner periphery of the protective cylinder and the outer periphery of the inner cylinder are closed by an upper end wall and a lower end wall, and the lower end of the inner cylinder is also closed by the lower end wall, and the cylindrical space is Inside, a large number of hollow fiber membranes are arranged in the vertical direction, and the upper end of each hollow fiber membrane is buried and closed in the upper end wall, and the lower end penetrates the lower end wall and is attached to the lower surface of the lower end wall. The inner cylinder is characterized by being open and provided with ventilation holes at the upper end, middle and lower part of the inner cylinder, and a treated water collecting chamber which is open to the bottom and is provided below the lower end wall.

Embodiment) Fig. 1 shows an embodiment of the filtration module according to claim 1, in which 11 is a vertical protection tube, 12 is arranged vertically inside the protection tube, and the lower part 12' is arranged vertically inside the protection tube. An inner cylinder protrudes downward from the lower end of the protection cylinder 11, 13 is a cylindrical space formed by the inner periphery of the protection cylinder and the outer periphery of the inner cylinder, and 14 is an upper end wall that closes the upper end of the cylindrical space. , 15 is a lower end wall that similarly closes the lower end of the cylindrical space, ]6... are arranged in the vertical direction inside the cylindrical space 13, and the upper end passes through the upper end wall 14 to face the upper surface of the wall. A large number of hollow fiber membranes are opened at the lower end and are closed by being buried in the lower end wall 15, 17 is a treated water collection chamber provided on the upper end wall 14, and 18 is a membrane that penetrates the lower end wall in the vertical direction. ventilation holes provided.

Reference numeral 19 indicates an air chamber provided under the lower end wall 15.

The housing cylinder 11 is made of hard plastic such as polyethylene, polypropylene, or acrylic, and in the part surrounding the cylindrical space 13, multiple holes 20 with a diameter of about 10 to 15 mm are opened in the vertical direction at equal intervals in the circumferential direction. It is. One inner cylinder 12 is arranged along the center of the protection cylinder, and is made of plastic or stainless steel. In this embodiment, the inner cylinder 12 has an upper portion that protrudes into a liquid collection chamber 17 on the upper end wall, and a water passage hole 2 that communicates with the inside of the liquid collection chamber 17 around the upper portion.
1 was opened.

The protection cylinder 11 also has an upper part that projects upward from the upper end wall 14 by the same amount as the inner cylinder 12, and the inner circumference of the annular upper wall 22 of the liquid collection chamber 17 and the upper end of the inner cylinder and the upper end of the protection cylinder are connected to each other. The outer periphery is fixed.

Then, on the upper wall 22, although the outer diameter is the same as that of the earthen wall,
An annular packing 23 having a larger inner diameter is fixed with adhesive or the like.

The upper end wall 14 and the lower end wall 15 are sheath parts made of hardened epoxy resin by botting, and an annular packing 24 is attached to the outer periphery of the lower surface of the lower end wall 15 by adhesive or the like, and surrounds the air chamber 19.

In Fig. 2, reference numeral 31 denotes a filter tower of a precoat type filtration device, which includes a cylinder body 32 having a bottom, a cover 33 having a flange on the lower side that overlaps the upper flange of the cylinder body, and an interior of the cylinder body. is divided into upper and lower parts by a partition plate 34, and the upper part is the filtration chamber 35.
．． The lower part is a take-out chamber 36 for treated water, and a raw water supply pipe 37 passes through the bottom of the barrel and the partition plate 34 to supply raw water in an upward flow into the filtration chamber 35, and then to the take-out chamber 36. The collected treated water is taken out of the tower through a take-out pipe 38.

The raw water supply pipe 37 is also used as a discharge port for cleaning waste water after membrane cleaning.

The upper flange of the cylinder body 32 and the lower flange of the cover 33 are used to hold bolts and nuts 4 with the upper side plate 39 sandwiched between them.
The upper side plate 39 is connected to the filtration chamber 35 and the cover 3.
Divide the inside of 3 into upper and lower parts. The cover 33 has an air vent 41, and the upper part of the processing chamber 35 is provided with an outlet 42 for discharging air during backwashing.

A plurality of hollow support stands 43 are arranged on the partition plate 34 to support the lower end of the filtration module. This support base 43 consists of a cylindrical part 44 whose lower end is fixed around a hole in the partition plate 34, and a saucer part 45 which is connected to the upper end of the cylindrical part 44 around a center hole in the bottom.

The outer diameter of the protective tube 11 of the aforementioned filtration module is matched to the inner diameter of the saucer portion 45, and the outer diameter of the inner tube 12 is matched to the inner diameter of the cylindrical portion 44, and this filtration module is used. In order to
are connected by an air supply pipe 47 that penetrates the upper side plate 39 watertightly, and air for backwashing is blown from the air vent 41, and the air diffuser pipe 46
In addition, the saucer part 4 of each support stand
A ventilation hole 48 is provided at the bottom of each support base, and a radial support 49 is installed in the cylindrical part 44 of each support base, and the upper end of the support 49 is located at the center of the support 49 so that the upper side plate 39 is lowered. The lower end of the support shaft 50 penetrating upward is attached by welding or the like, and is made to stand upright.

To set the above-mentioned filtration module, remove the cover 33 and the upper side plate 39, and attach the support shaft 5 that stands upright from each support stand 43.
0 into the inner cylinder 12, lower the module onto the support stand 43, fit the lower end of the inner cylinder into the inner periphery of the cylindrical part 44 of the support stand, and fit the lower end of the protection cylinder 11 into the saucer part 45. , the packing 24 surrounding the air chamber 19 is compressed to the bottom of the saucer portion 45. Then, the packing 23 of the module and the restraining plate 51 that comes into contact with the inner circumference of the upper wall 22 of the liquid collection chamber are fitted onto the support shaft 50, and tightened from above with a nut 52. For this purpose, the support shaft 50 has a stopper 5 at its upper end that receives the restraining plate 51 from below.
3, and a male screw 54 with a thin diameter is formed above the step 53.

Note that the height or level of the step 53 is the upper wall 2 of the module.
It is aligned with the top surface of 2.

After the modules are erected on all the support stands 43 in this way, the upper side plate 39 is placed on the flange around the cylinder body 32, and the male screw 54 at the upper end of each support shaft is made to protrude upward from the hole in the upper side plate. A nut 55 screwed into this male screw 54 is tightened against the upper and lower sides to prevent each module from swinging. Then, the cover 33 is placed on the upper side plate, and the flanges of the cylinder body 32 and the cover 33, and the peripheral edge of the upper side plate are joined together with bolts and nuts 40 in an overlapping state.

To perform filtration, raw water is pressurized and supplied into the filtration chamber 35 through the supply pipe 37. This allows the raw water to flow through the hole 20 of the protection tube 11.
The crud in the raw water enters the cylindrical space 13 of the module, and the crud in the raw water is captured by the cylindrical membrane wall of the hollow fiber membrane 16, and only the treated water passes through the membrane wall and flows into the hollow section. The treated water then rises through the hollow section and collects in the liquid collection chamber 17 on the upper end wall 14.
Water flows from the membrane chamber into the inner cylinder 12 through the water passage hole 21, descends through the inner cylinder, and flows from the cylindrical part 44 of the support stand to the extraction chamber 3 of the filtration device.
6 and is taken out through the take-out pipe 38.

When the head loss increases, backwashing is performed and the hollow fiber membrane 16...
・Remove the captured crud. To do this, after washing water is pressurized from the take-out pipe 38, air is blown into the air vent 41 and is ejected from the aeration pipe 46 into the processing chamber 35.

By water backwashing, the cleaning water rises from the take-out chamber 36 into the inner cylinder 12 of each module, flows downward from the liquid collecting chamber 17 into the hollow portion of the hollow fiber membrane 16, and flows downward into the hollow fiber membrane 16. It passes through the cylindrical membrane wall in reverse. After that, the air ejected from the diffuser pipe 46 becomes fine bubbles and enters the air chamber 19 through the ventilation hole 48 at the bottom of the saucer part 45 of the support base, and from there the lower end wall]5
While ascending through the cylindrical space 13 through the ventilation hole 18 located in the hollow fiber membrane 16, it comes into contact with the outer surface of the hollow fiber membrane 16, and promotes the peeling of the cladding captured by the hollow fiber membrane.

In this way, the cladding is peeled off from the hollow fiber membrane by the cleaning water that permeates the cylindrical membrane wall of the hollow fiber membrane from the inner periphery to the outer periphery and the air bubbles that rise while contacting the surface of the membrane wall, and the cladding is removed from the hole 20 of the protection tube 11. It comes out of the module along with cleaning water and air bubbles.
It is discharged from the apparatus through the discharge port 37, and the filtration process is restarted after washing is completed.

FIG. 3 shows an embodiment of the filtration module according to claim 2, in which 61 is a vertical protection tube, 62 is arranged inside the protection tube in the vertical direction, and an upper part 62' is an upper end of the protection tube. 63 is a cylindrical space formed by the inner periphery of the protection cylinder and the outer periphery of the inner cylinder; 64 is an upper end wall that closes the upper end of the cylindrical space; 65 is also the cylinder; Lower end walls 66 that close the lower end of the shaped space are arranged in the vertical direction inside the cylindrical space 63, their upper ends are buried and closed in the upper end wall 64, and their lower ends are closed in the lower end wall 65. A large number of hollow fiber membranes are penetrated and open on the lower surface of the membrane wall, 67 is a treated water collecting chamber provided under the lower end wall 65, and 68 is a ventilation hole provided around the upper end of the inner cylinder. As shown, the protective tube 61. The material of the inner cylinder 62 may be the same as that of the above-mentioned embodiment, and the protective cylinder 61 is similarly provided with a plurality of holes 69 in the vertical direction. Also, the inner cylinder 62
It has a lower end of a cylindrical space 63 and a ventilation hole 70 located in the middle.

The upper end wall 64 and the lower end wall 65 are sheath portions made of hardened epoxy resin by botting, and an annular packing 71 surrounding the liquid collection chamber 67 is fixed to the outer periphery of the lower surface of the lower end wall by adhesive or the like.

FIG. 4 shows a filter tower of the same precoat type filtration device as FIG. 2, and the same components are given the same reference numerals.

Modifications for using the filtration module shown in FIG. 3 in this filtration tower include making it possible to blow air into the air vent 41 in the cover 33, and installing a support in the cylindrical part 44 of the hollow support 43. 49 fixes the lower end of the support shaft 50 and when the support shaft 50 is made to stand upright, an inner cylinder 6 is attached to the upper side plate 39.
It is only necessary to open a hole 56 through which the upper end of the air diffuser 2 can pass upward, and there is no need to install the air diffuser pipe 46.

To set the module, remove the cover 33 and the upper side plate 39, fit the center hole 72 of the lower end wall 65 that closed the inside of the lower end of the inner tube 62 into the upper end of each support shaft 50, and lower the module onto the support stand 43. The lower end of the protection tube 61 is fitted into the inner periphery of the saucer section 45, and the annular packing 71 surrounding the liquid collection chamber 67 is compressed onto the bottom of the saucer section 45. In order to seal the center hole 72 of the lower end wall from below, a collar 50' is fixed to the lower end of the support shaft 50, and an O-ring 57 is placed on the upper surface.
The O-ring 57 is preferably compressed around the center hole in the lower surface of the lower end wall 65 when the module is lowered onto the tray.

After all the modules are erected on the support bases 43 in this way, the upper side plate 39 is placed on the upper flange of the cylinder body 32, and the upper end of the inner cylinder 62 of each module is made to protrude upward from the hole 56 in the side plate. Screw the nut 58 into the male thread on the outer periphery of the upper end of the inner cylinder and tighten it against the upper side plate.
External thread 54 at the upper end of the support shaft protruding upward from the upper end of 2
Screw in the nut 59 and tighten it against the upper end of the inner cylinder,
At the same time, a hole 56 in the upper side plate is closed with a nut 59 to close the upper end of the inner cylinder 62. Nuts 58,59 effectively prevent the module from shaking.

To perform filtration, raw water is pressurized and supplied into the filtration chamber 35 through the supply pipe 37. As a result, the raw water flows into the hole 69 of the protection tube 61.
The crud in the raw water enters the cylindrical space 63 of the module, and the crud in the raw water is captured by the cylindrical membrane wall of the hollow fiber membrane 66, and only the treated water passes through the membrane wall and flows into the hollow part. Then, the treated water descends through the hollow part and collects in the collection chamber 67 under the lower end wall 65, and passes through the tube 44 of the support stand and into the extraction chamber 36 of the filtration device.
and is taken out through the take-out pipe 38.

When the head loss increases, backwashing is performed and the hollow fiber membrane 66...
・Remove the captured crud. For this purpose, air is blown into the air vent 41 after washing water is pressurized from the take-out pipe 38. As a result, the washing water flows upward from the extraction chamber 36 through the cylindrical portion 44 of the support stand and the liquid collection chamber 67 into the hollow portion of the hollow fiber membrane 66, and reverses the cylindrical membrane wall of the hollow fiber membrane. To Penetrate. After that, the air blown into the cover 33 from the air vent 41 is transferred to the inner cylinder 62 from the ventilation hole 68 at the upper end of the inner cylinder 62.
The air enters the cylinder and descends inside the cylinder, and is ejected in the form of fine bubbles into the cylindrical space 63 from the ventilation holes 70 in the lower and middle parts of the inner cylinder.
While rising in the cylindrical space 63, it comes into contact with the outer surface of the hollow fiber membranes 66, and promotes peeling of the cladding captured by the hollow fiber membranes.

In this way, the cladding is peeled off from the hollow fiber membrane by the cleaning water that permeates the cylindrical membrane wall of the hollow fiber membrane from the inner circumference to the outer circumference and the air bubbles that rise while contacting the surface of the membrane wall, and the cladding is peeled off from the hollow fiber membrane through the hole 69 of the protection tube 61. It exits the module together with the washing water and is discharged from the apparatus through the outlet 37, and after the washing is completed, the filtration process is restarted.

<Effects of the Invention> According to the present invention, the internal structure of a pre-coat type filtration tower using an existing pre-coat type filtration module, for example, a condensate filter in a BWR type nuclear power plant, can be improved without large-scale remodeling. A hollow fiber membrane filtration module that can perform filtration and backwashing can be provided.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an embodiment of the filtration module according to claim 1, FIG. 2 is a sectional view of a filtration tower showing the usage state of the filtration module of FIG. 1, and FIG. FIG. 4 is a sectional view of a filtration tower showing a state in which the filtration module of FIG. 3 is used. In the figure, 11.61 is a protection cylinder, 12.62 is an inner cylinder, 13,
63 is a cylindrical space, 14.64 is an upper end wall, 15.65 is a lower end wall, 16.66 is a hollow fiber membrane, 17.67 is a liquid collection chamber, 1
8.68.70 indicates a ventilation hole, and 19 indicates an air chamber.

Claims (2)

[Claims] (1) Inside a vertical protection cylinder through which raw water flows, an inner cylinder whose lower part projects downward from the lower end of the protection cylinder is arranged in the vertical direction, and the inner circumference of the protection cylinder and the outer circumference of the inner cylinder are arranged in the vertical direction. The upper and lower ends of the cylindrical space formed by the cylindrical space are closed by an upper end wall and a lower end wall, and a large number of hollow fiber membranes are arranged in the vertical direction inside the cylindrical space, and the upper end of each hollow fiber membrane is connected to the upper end of the cylindrical space. It penetrates the wall and opens onto the upper end wall, and the lower end is buried and closed in the lower end wall, and a treated water collection chamber communicating with the inner cylinder is provided on the upper end wall, and the lower end wall A filtration module using a hollow fiber membrane, characterized in that a ventilation hole is provided that penetrates in the vertical direction, and an air chamber that is open to the bottom is provided below the lower end wall. (2) An inner cylinder whose upper part projects upward from the upper end of the protection cylinder is arranged in the vertical direction inside the protection cylinder in the vertical direction through which the raw water flows, and the inner periphery of the protection cylinder and the outer periphery of the inner cylinder are arranged in the vertical direction. The upper and lower ends of the cylindrical space formed by the inner cylinder are closed by an upper end wall and a lower end wall, and the lower end of the inner cylinder is also closed by the lower end wall, and inside the cylindrical space, a large number of hollow fiber membranes are installed in the vertical direction. and the upper end of each hollow fiber membrane is buried and closed in the upper end wall, and
The lower end penetrates the lower end wall and opens on the lower surface of the lower end wall, and ventilation holes are provided at the upper end, middle and lower part of the inner cylinder, and a treated water collection hole is opened below the lower end wall. A filtration module using a hollow fiber membrane characterized by having a chamber.