TWM520939U - Membrane module - Google Patents

Description

Membrane module

The present invention relates to a membrane module for treating a liquid such as a liquid in which impurities in a liquid are removed.

In the conventional water treatment for removing impurities in water, a membrane module having a hollow fiber membrane is used. In the filtration step of the water treatment, the raw water (water before filtration) is supplied into the membrane module through the raw water inlet provided in the membrane module, and the filtered water that has passed through the membrane passes through the filtered water outlet provided in the membrane module to the membrane mold. Excreted outside the group.

In the case of a membrane module, when a filtration step of water treatment is performed, substances (SS: Suspended Solids) which are removed from the water are accumulated on the surface of the membrane. Therefore, efficient removal of suspended matter deposited on the surface of the film is one of the important issues.

Generally, the removal of suspended solids is carried out by so-called backwashing (reverse pressure washing). In the backwashing step, the suspended matter adhering to the surface of the film is allowed to float from the film, and a fluid flowing in the opposite direction to the filtering step is formed in the film module. That is, the fluid (gas or liquid) is supplied to the membrane module through the filtered water outlet, and the fluid that has passed through the membrane is discharged to the outside of the membrane module via the raw water inlet.

Floating locally from the surface of the film as the backwashing step proceeds The suspended matter in the state is peeled off from the surface of the film in accordance with the subsequent foaming step. In this foaming step, air is supplied while the membrane module is filled with water, and the membrane is shaken depending on the foam of the supplied air. Therefore, the suspended matter on the surface of the film is peeled off. The membrane module is provided with a gas diffusion member that supplies air to a plurality of vent holes for the hollow fiber membrane in the foaming step (see, for example, Patent Documents 1 to 4 below).

In the hollow fiber membrane module of Patent Document 1, an air disperser for air dispersion induction from the air supply header is provided on the lower side of the hollow fiber membrane. The hollow fiber membrane module of Patent Document 2 has an air supply portion provided in a resin plate. In Patent Document 2, when the cross-sectional area of the air supply unit is S, a through hole is provided only in a region of 0.5 S in contact with the central portion of the air supply unit. In the hollow fiber membrane module of Patent Document 3, a gas diffusion mechanism that generates bubbles from the lower end side of the hollow fiber membrane is formed so as to be diffused to the hollow fiber membrane extending in the vertical direction. In the membrane separation apparatus for immersion of Patent Document 4, a gas diffusion device having a gas introduction hole is provided.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. Hei 11-033367

[Patent Document 2] Japanese Patent Laid-Open Publication No. 2006-239642

[Patent Document 3] Japanese Patent Laid-Open Publication No. 2009-285532

[Patent Document 4] Japanese Patent No. 4530245

However, in the air supply structure disclosed in any one of Patent Documents 1 to 4, there is a problem that the suspended matter adhering to the outer peripheral portion of the hollow fiber membrane cannot be efficiently removed.

The purpose of the present invention is to efficiently remove suspended matter adhering to the outer peripheral portion of the film member in a membrane module for performing liquid treatment for removing impurities in a liquid.

The membrane module of the present invention comprises: a casing; a membrane member disposed in the casing; and a diffusing member having a plurality of passages for supplying gas to the membrane member below the membrane member provided in the casing Stomata. The size of the above-described air diffusing member in the horizontal direction is larger than the size of the aforementioned film member in the aforementioned horizontal direction. A part of the plurality of vent holes is provided so as to be positioned outside the aforementioned film member in the horizontal direction.

1‧‧‧ membrane module

2‧‧‧ Shell

3‧‧‧membrane components

4‧‧‧ diffusing components

5‧‧‧ Hollow

6‧‧‧Support members

6A‧‧‧ pillar

6B‧‧‧Lower joint member

7‧‧‧Fixed components

10‧‧‧ original sink

11‧‧‧1st Pass

12‧‧‧2nd entrance

13‧‧‧ Ventilation

14‧‧‧ gas supply port

15‧‧‧ Guide tube

21‧‧‧Cylinder

22‧‧‧ Lower side cover

23‧‧‧Upper side cover

31‧‧‧The outer part

40‧‧‧ Body Department

41‧‧‧Air Department

41S‧‧‧ accommodating space

42‧‧‧Walls

43, 431, 432, 433, 434‧‧ vents

44‧‧‧Dispersed holes

45‧‧‧Auxiliary vents

100‧‧‧Water treatment unit

101‧‧‧ original sink

102‧‧‧ gas supply device

103‧‧‧Processing sink

110, 111, 112, 113, 114, 115‧‧‧ piping

120‧‧‧ pump

130, 131, 132, 133, 134, 135‧ ‧ valves

204‧‧‧Distribution plate

A, A1, A11‧‧ Center

C1~C4‧‧‧Circle

D1‧‧‧Diameter (the horizontal dimension in the diffuser 4)

D2‧‧‧ size

D3‧‧‧ Inner diameter (inner dimension in the horizontal direction of the outer casing 2)

G‧‧‧ gap

SS‧‧‧suspension

Fig. 1 is a schematic view showing an example of a water treatment apparatus including a membrane module of the embodiment of the present invention.

Fig. 2A is a cross-sectional view showing a film module of the embodiment, and Fig. 2B is a cross-sectional view taken along line II-II of Fig. 2A.

Fig. 3A is a plan view showing a gas diffusion member of the membrane module of the embodiment, and Fig. 3B is a sectional view taken along line III-III of Fig. 3A.

Fig. 4 is a schematic view showing a lower portion of the membrane module of the embodiment, in which the size and positional relationship of the outer casing, the diffusing member, and the membrane member are compared with each other and the positional relationship between the outer casing and the diffusing member in the comparative example.

5A is a cross-sectional view taken along line VA-VA of FIG. 2, and FIG. 5B is a cross-sectional view taken along line VB-VB of FIG. 5A.

6A and 6B are graphs showing the results of performance evaluation of the membrane module.

Fig. 7 is a schematic view showing a modified example of the air diffusion member in the membrane module of the embodiment.

Fig. 8 is a schematic view showing a modification of the membrane module of the embodiment, showing a membrane module of both ends fixed.

Hereinafter, the form for carrying out the present creation will be described in detail with reference to the drawings. The membrane module 1 of the embodiment of the present invention can be used, for example, in the water treatment apparatus 100 shown in Fig. 1 . The water treatment device 100 is a device that reduces the concentration of impurities contained in the water by separating the solid content contained in the raw water (water to be treated) in the membrane module 1. For the removal of impurities (removal of the target substance), for example, turbidity, iron ions, manganese ions, and the like in water such as river surface water, ground water, and lake water are used, but the substance to be removed is not limited to the above turbidity or metal. ion.

[Overall structure of water treatment device]

The water treatment device 100 includes a membrane module 1 , a raw water tank 101 , a gas supply device 102 , a treatment tank 103 , a plurality of pipes 110 to 115 connected thereto, a pump 120 provided in the pipe 110 , and a plurality of pipes provided in the pipe Valves 130~135.

In the case of the membrane module 1, a membrane-treated water having a solid content (suspended matter) separated from raw water and having a reduced solid content can be obtained. As for the membrane module 1, for example, a hollow fiber membrane module 1 having a hollow fiber membrane can be used. In the hollow fiber membrane module 1, a structure in which the hollow fiber membrane 3 as the membrane member 3 is provided in the elongated cylindrical outer casing 2 can be exemplified, but is not limited thereto. The membrane module 1 is only required to be separated from raw water into solid content and membrane treated water. The function of the separator may be a structure in which the separation membrane other than the hollow fiber membrane is provided in the outer casing 2.

In terms of the material of the hollow fiber membrane, various materials can be used, and it is not particularly limited. For example, it is preferable to contain at least one selected from the group consisting of polyethylene, polypropylene, polyacrylonitrile, and ethylene-tetrafluoroethylene. Copolymer, polychlorotrifluoroethylene, polytetrafluoroethylene, polyvinyl fluoride, tetrafluoroethylene-hexafluoropropylene copolymer, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, chlorotrifluoroethylene-ethylene copolymer Polyvinylidene fluoride, polyfluorene, cellulose acetate, polyvinyl alcohol and polyether oxime are more preferably polyvinylidene fluoride (PVDF) from the viewpoint of film strength and chemical resistance.

In the hollow fiber membrane module 1, the hollow fiber membrane is modularized. Specifically, the hollow fiber membrane module 1 includes, for example, a tens of hundreds to hundreds of thousands of hollow fiber membranes bundled and arranged in a U shape in the outer casing 2, and a hollow fiber bundle One end of the hollow fiber bundle is sealed by a suitable sealing material, a state in which one end of the hollow fiber bundle is not fixed by an appropriate sealing material (unconstrained state), and both ends of the hollow fiber bundle The shape of the opening, etc. The shape of the hollow fiber membrane module 1 is not particularly limited, and may be, for example, a cylindrical shape or a mesh shape. In particular, the single-ended fixed type (single-ended unconfined type) hollow fiber membrane module 1 that is sealed in an unconstrained state is capable of efficiently stripping and discharging the adhered substance by gas back pressure cleaning. Preferably.

In the filtration method of the hollow fiber membrane module 1, an external pressure filtration method such as external pressure total filtration or external pressure circulation filtration can be exemplified, and the conditions of the membrane separation treatment and the required performance can be appropriately selected. In terms of the life of the membrane, it is possible to simultaneously wash the surface of the membrane. The ring method (external pressure circulation filtration method) is preferable, and the total amount filtration method (external pressure total filtration method) is preferable in terms of equipment simplicity, installation cost, operation cost, and the like.

Further, in the membrane module 1 of the external pressure filtration type such as the external pressure total filtration or the external pressure circulation filtration, the suspended solids contained in the raw water are removed at a higher ratio on the outer side of the membrane member 3 which is efficiently filtered. . Therefore, the adhesion amount of the suspended matter adhering to the outer peripheral portion 31 of the film member 3 becomes larger than the amount of adhesion in the inside of the film member 3. Therefore, the diffuser disk 4 of the present embodiment is particularly suitable for the membrane module 1 of the external pressure filtration type. However, it is not limited to the membrane module 1 of the external pressure filtration method.

The raw water tank 101 is a container for storing raw water containing suspended matter. In the case where the target substance is, for example, a metal ion, an additive such as an oxidizing agent is added to the water storage tank (not shown) on the upstream side of the raw water tank 101 or the raw water tank 101, and the metal ions in the raw water are solid content. Ways to precipitate. In the case where the target substance is originally a solid content, the precipitation treatment system can be omitted. As for the gas supply device 102, for example, an air compressor or the like can be used.

[Structure of membrane module]

Next, the structure of the membrane module 1 of the present embodiment will be described in detail. As shown in FIGS. 2A and 2B, the membrane module 1 includes a casing 2, a membrane member 3, a diffuser 4 as a diffusing member, a supporting member 6, and a fixing member 7 (see FIG. 5). The membrane module 1 of the present embodiment is a single-end fixed type (single-ended unconfined type) membrane module in which the upper end portion of the membrane member 3 is fixed to the outer casing 2 and the lower end portion of the membrane member 3 is in an unconstrained state. .

As shown in FIG. 2A, the outer casing 2 has a slender shape in the up and down direction. Cylindrical. The outer casing 2 has a tubular portion 21 extending in the vertical direction, a lower opening lower side cover portion 22 that blocks the tubular portion 21, and an upper opening upper side cover portion 23 that blocks the tubular portion 21. The outer casing 2 is provided with a first port 11 (raw water inlet 11), a second port 12 (filtered water outlet 12), a vent 13 and a gas supply port 14.

The first port 11 is provided below the film member 3. In the present embodiment, the first port 11 is provided on the lower lid portion 22, but the present invention is not limited thereto, and may be provided in the tubular portion 21. The first port 11 functions as a raw water inlet for supplying raw water into the outer casing 2 in the filtration step, and is discharged as a drain water to be discharged from the outer casing 2 in a backwashing step, a foaming step, or the like. Exports function.

The second port 12 is provided above the film member 3. In the present embodiment, the second port 12 is provided in the upper cover portion 23, but may be provided in the tubular portion 21. The second port 12 functions as a filtered water outlet for discharging the membrane-treated water (membrane-filtered water) from which the suspended matter has been removed in the filtration step to the outside of the outer casing 2, and also serves as a fluid for supplying the fluid toward the outer casing 2 in the backwashing step. The supply port functions.

The air vent 13 is provided above the first port 11 and below the second port 12 . In the present embodiment, the air vent 13 is provided in the tubular portion 21. The vent 13 serves as a discharge port for discharging the air in the outer casing 2 to the outside of the outer casing 2 as needed in each step.

The gas supply port 14 is provided below the membrane member 3. In the present embodiment, the gas supply port 14 is provided in the lower cover portion 22, but the present invention is not limited thereto, and may be provided in the tubular portion 21. The gas supply port 14 serves as a bubble forming step in the outer casing 2 in a state in which the outer casing 2 is filled with water. The supply port for supplying air functions. As shown in FIG. 2A, the air supplied from the gas supply port 14 flows into the guide pipe 15 (guide portion 15) provided directly below the air receiving portion 41, which will be described later. Therefore, the air supplied from the gas supply port 14 is efficiently accommodated in the air receiving portion 41.

The film member 3 has an elongated shape extending in the vertical direction from the vicinity of the upper end of the tubular portion 21 to the vicinity of the lower end in the outer casing 2. As shown in FIG. 2B, the film member 3 has an annular shape in plan view so that the hollow portion 5 is formed inside. The film member 3 can be formed by a plurality of hollow fiber bundles arranged in a plurality in the circumferential direction to form an annular film member 3, or can be formed by forming a single hollow fiber bundle of a ring shape. Further, the hollow portion 5 may be omitted, and in this case, the film member 3 has a columnar shape.

As shown in FIG. 2A, the film member 3 is fixed to the outer casing 2 by the support member 6. In the present embodiment, the support member 6 has a support 6A and a lower connection member 6B. However, the support member 6 is not limited to the form shown in FIG. 2A as long as the film member 3 can be fixed to the outer casing 2.

The pillar 6A is disposed in the hollow portion 5 and extends in the vertical direction. The upper end portion of the film member 3 is fixed to the upper end portion of the stay 6A. A lower end portion connecting member 6B for fixing the stay 6A to the lower end portion of the outer casing 2 is connected to the lower end portion of the stay 6A.

The air diffusing disc 4 is used to disperse the air supplied from the gas supply port 14 into the outer casing 2 in the foaming step toward the region where the membrane member 3 is disposed. The diffuser tray 4 is disposed below the membrane member 3 in the outer casing 2. As shown in FIGS. 3A and 3B, the diffuser disk 4 includes a main body portion 40, an air receiving portion 41, and a peripheral wall portion 42, and these are integrally formed.

The body portion 40 has a disk shape (circular in plan view) The shape of the plate). A plurality of vent holes 43 are provided in the body portion 40. The plurality of vent holes 43 are provided for supplying the air supplied into the casing 2 from the gas supply port 14 located below the diffuser disk 4 to the film member 3 positioned above the diffuser disk 4, and are provided above and below. The direction passes through the hole of the diffuser disk 4.

The plurality of vent holes 43 are arranged in a wide range in which the air is dispersed in the film member 3, and are spaced apart from each other in the radial direction and the circumferential direction of the main body portion 40 of the diffuser disk 4. In the present embodiment, a plurality of vent holes 43 are provided in the main body portion 40, and are not provided in the peripheral wall portion 42. However, as in the modification shown in FIG. 7 to be described later, the diffuser disk 4 may have one or a plurality of auxiliary vent holes 45 provided in the peripheral wall portion 42 in an auxiliary manner. The details of the plurality of vents 43 are as follows.

The air receiving portion 41 is provided on the lower side of the main body portion 40 so as to temporarily accommodate the gas supplied into the casing 2 via the gas supply port 14 . Further, the air receiving portion 41 is provided directly above the guide tube 15 (the guide portion 15). In the present embodiment, the air receiving portion 41 has a cylindrical shape. The outer diameter of the air receiving portion 41 is smaller than the diameter of the main body portion 40. The upper end of the air receiving portion 41 is connected to the lower surface of the body portion 40. Thereby, the accommodating space 41S surrounded by the inner peripheral surface of the air receiving portion 41 and the lower surface of the main body portion 40 is formed. Further, the shape of the main body portion 40 is not limited to a cylindrical shape, and for example, the cross section may be a polygonal cylindrical shape.

The air receiving portion 41 has a plurality of dispersion holes 44. Each of the plurality of dispersion holes 44 is a through hole penetrating through the cylindrical wall constituting the air inlet portion 41. The plurality of dispersion holes 44 are for allowing the gas accommodated in the accommodating space 41S of the air receiving portion 41 to be distributed below the main body portion 40 to the radially outer side (horizontal outer side) of the air receiving portion 41. In the present embodiment, the plurality of dispersion holes 44 are arranged at equal intervals in the circumferential direction, but are not limited thereto, and adjacent to each other This interval may not be constant.

The peripheral wall portion 42 is for suppressing the air supplied to the radially outer side of the air receiving portion 41 via the plurality of dispersion holes 44 to move radially outward of the main body portion 40. The peripheral wall portion 42 has a tubular shape that extends downward from the peripheral edge of the body portion 40. The dimension of the upper and lower sides of the peripheral wall portion 42 is smaller than the dimension of the upper and lower sides of the air receiving portion 41. That is, the lower end of the peripheral wall portion 42 is located higher than the lower end of the air receiving portion 41.

The plurality of dispersion holes 44 provided in the air receiving portion 41 are provided at a position higher than the lower end of the peripheral wall portion 42 (a position close to the main body portion 40). As a result, it is possible to suppress the effect that the air supplied to the radially outer side of the air receiving portion 41 via the plurality of dispersion holes 44 is moved radially outward of the main body portion 40.

As shown in Fig. 3, in the present embodiment, all of the vent holes 43 are provided in the main body portion 40 in the radially outer side (horizontal outer side) of the air receiving portion 41, but are not limited thereto, and may be one portion. The vent hole 43 is provided in the main body portion 40 on the radially inner side of the air receiving portion 41.

As shown in FIG. 3A, a plurality of vent holes 43 are arranged on a plurality of circumferences C1 to C4 centering on the center A of the body portion 40 of the diffuser disk 4. The plurality of vent holes 43 have the first vent holes 431 arranged on the outer circumference C1, and the second vent holes 432 arranged on the circumference C2 having a smaller diameter than the circumference C1, and arranged in a smaller diameter than the circumference C2. The third vent hole 433 on the circumference C3 and the fourth vent hole 434 arranged on the circumference C4 having a smaller diameter than the circumference C3. The vent holes 43 on the respective circumferences are arranged at equal intervals, but are not limited thereto. Further, in the present embodiment, the vent holes 43 are arranged on the four circumferences C1 to C4, but the number of circles may be a complex number other than four. also, A part of the vent hole 43 may also be provided at a position other than the circumference.

As shown in Fig. 3A, in the present embodiment, the interval between the plurality of vent holes 431 arranged on the outermost circumference C1 is narrower than the plurality of vent holes arranged on the circumference C2 to C4 on the radially inner side thereof. The interval between 432, 433, and 434. That is, the arrangement density of the plurality of vent holes 431 arranged on the outermost circumference C1 is higher than the arrangement of the plurality of vent holes 432, 433, 434 arranged on the circumference C2 to C4 radially inward of the inner side. density. Further, in the present embodiment, the plurality of vent holes 434 arranged on the innermost circumference C4 are spaced apart from each other by a plurality of vent holes 431, 432, 433 arranged on the outer circumferences C1 to C3 radially outward. The interval is also wide. Further, in the present embodiment, the interval between the vent holes 43 becomes narrower as it approaches the radially outer side. However, regardless of the position in the radial direction, the interval between the vent holes 43 may be constant.

The inner diameter of the first vent hole 431 provided on the outermost circumference C1 is larger than the inner diameter of the vent holes 432, 433, and 434 provided on the radially inner side. Therefore, compared with the case where the inner diameter of the plurality of vent holes 43 is the same (the second embodiment to be described later), the gas which is guided to the gas above the diffuser disk 4 via the first outer vent hole 431 located in the radially outer side can be improved. proportion. Therefore, the suspended matter SS adhering to the outer peripheral portion 31 of the film member 3 can be removed more efficiently than in the second embodiment (see the graph of FIG. 6A to be described later).

In the present embodiment, the inner diameters of the vent holes 432, 433, and 434 are the same, but are not limited thereto. For example, the first vent hole 431, the second vent hole 432, the third vent hole 433, and the fourth vent hole 434 may be formed in the order of decreasing the inner diameter.

(A) of FIG. 4 shows the lower portion of the membrane module 1 of the embodiment. The outline shows the size and positional relationship of the outer casing 2, the diffuser disk 4, and the film member 3. Fig. 4(B) shows the positional relationship between the outer casing 2 and the diffuser disk 204 in the comparative example.

As shown in (A) of FIG. 4, the diameter D1 of the diffuser disk 4 (the dimension D1 in the horizontal direction in the diffuser disk 4) is larger than the dimension D2 from the side in the horizontal direction to the other side in the film member 3. . In the first embodiment, the first vent hole 431 provided on the outermost circumference C1 is such that the center A1 of the first vent hole 431 is located radially outward of the film member 3 (horizontal outward side). Settings.

In this manner, since the first vent hole 431 is disposed radially outward of the film member 3, a part of the gas supplied to the film module 1 is borrowed in the foaming step after the backwashing step. The first vent hole 431 located radially outward of the film member 3 is guided to the upper side of the diffuser disk 4. This gas system can reach the suspended matter SS attached to the outer peripheral portion 31 of the film member 3 by rising as in the liquid.

5A is a cross-sectional view taken along line VA-VA of FIG. 2, and FIG. 5B is a cross-sectional view taken along line VB-VB of FIG. 5A. 4(A) and FIG. 5A and FIG. 5B, the inner diameter D3 of the outer casing 2 (the inner dimension D3 in the horizontal direction in the outer casing 2) is larger than the diameter D1 of the air diffusing disk 4. Therefore, a gap G is formed between the inner side surface of the outer casing 2 and the air diffusing disk 4. This gap G functions as a passage for guiding the suspended matter SS which is peeled off from the surface of the film member 3 by the foaming step to the lower side of the diffuser disk 4. Thereby, the suspended matter SS removed from the surface of the film member 3 is efficiently discharged outside the outer casing 2 via the first port 11 (see FIG. 2). Further, the configuration is not limited to the case where the gap G is formed between the inner side surface of the outer casing 2 and the air diffusing disc 4, and the gap G may not be formed.

In contrast, in the diffuser disk 204 in the comparative example shown in FIG. 4(B), the diameter D11 of the diffuser disk 204 is smaller than the dimension D2 of the film member 3 from one side in the horizontal direction to the other side. Further, in the diffuser disk 204 of the comparative example, the vent hole 432 provided on the outermost circumference of the vent hole 432 is provided such that the center A11 of the vent hole 432 is located radially inward of the film member 3.

In the present embodiment, as shown in FIGS. 5A and 5B, the diffuser disk 4 is fixed to the outer casing 2 by a plurality of fixing members 7. In the present embodiment, each of the fixing members 7 is a member having a substantially L shape, but is not limited thereto. Further, the number of the fixing members 7 may be set to one without providing a plurality of them.

When the air diffusing disk 4 is fixed in the outer casing 2 by the fixing member 7, first, one end portion of each of the fixing members 7 is fixed by a fixing means such as welding to the air diffusing disk 4. Thereafter, the air diffusing disc 4 fixed by the plurality of fixing members 7 is fitted into a predetermined position in the outer casing 2, and fixed at a position thereof by fixing means such as welding the inner surface of the outer casing 2. Thereby, the air diffusing disk 4 is fixed to the outer casing 2 in a state of being disposed at the central portion in the outer casing 2.

[Operation of water treatment device]

A plurality of steps including a filtration step, a backwashing step, and a foaming step are performed in the water treatment apparatus 100.

First, before the filtration step, the preparation step is to fill the inside of the outer casing 2 with raw water (first water filling step). When the raw water is filled in the outer casing 2 in the first water filling step, the valve 132 is opened. Therefore, the air-containing fluid in the outer casing 2 flows out from the air discharge port 13 provided in the outer casing 2 to the pipe 112.

In the filtering step, the valves 130, 131 are set to the open state The pump 120 is operated. Therefore, the raw water in the raw water tank 101 is supplied into the membrane module 1 from the first port 11 (raw water inlet 11) via the pipe 110. The material to be removed contained in the raw water to be supplied is captured in the film member 3. The membrane-treated water (filtered water) whose concentration of the target substance is removed by the membrane member 3 flows out from the second port 12 (filtered water outlet 12) to the pipe 111 and is collected by the treatment tank 103.

When the membrane module 1 performs the filtration step, a solid content (suspended matter) containing the substance to be removed is adhered to the membrane member 3. After a predetermined period of time after the start of the filtration step in the membrane module 1, the filtration step is temporarily stopped, and a backwashing (reverse pressure washing) step for removing the solid content adhering to the membrane member 3 from the membrane member 3 is performed. Bubble step.

In the backwashing step, in order to float the solid content accumulated and adhered to the surface of the film member 3 from the film member 3, a fluid flow in a direction opposite to the filtering step is formed in the film module 1. That is, the valves 134 and 135 are in an open state, and air is supplied from the gas supply device 102 such as an air compressor to the outer casing 2 via the second port 12 (filtered water outlet 12). The air that has flowed into the outer casing 2 acts on the solid content of the surface attached to the membrane member 3. Thereby, the solid content becomes a state partially floating from the surface of the film member 3.

In the case where the fluid passes through the membrane member 3 in the outer casing 2, the fluid is discharged to the outside of the outer casing 2 via the first port 11 (raw water inlet 11). The waste water discharged outside the outer casing 2 is drained through the pipe 114.

The solid content in a state in which the surface of the film member 3 is partially floated by the backwashing step is peeled off from the surface of the film member 3 in the subsequent foaming step. Further, in terms of the fluid in the backwashing step, the air supplied from the gas supply device 102 as described above may not be used. Use a liquid such as water.

Before the foaming step, the preparation step is to fill the inside of the outer casing 2 with raw water (second water filling step). When the raw water is filled in the outer casing 2 in the second water filling step, the valve 132 is set to the open state. Therefore, the air-containing fluid in the outer casing 2 flows out from the air discharge port 13 provided in the outer casing 2 to the pipe 112.

In the foaming step, the valves 134, 135 are set to the closed state, and the valve 133 is set to the open state. Next, the compressed air is sent through the pipe 113 through the gas supply device 102, and is supplied from the gas supply port 14 into the casing 2. In this foaming step, the film member 3 is shaken by the foam of the air supplied into the film module 1, and therefore, the solid content of the surface of the film member 3 is peeled off.

When the foaming step is completed, the water in the outer casing 2 is drained through the piping 114 (draining step). After the drainage step, the filtration step is started again.

〔Evaluation results〕

6A and 6B are graphs showing the results of performance evaluation of the membrane module. In Fig. 6A and Fig. 6B, the first embodiment is a membrane module 1 in which the diffusing disk 4 shown in Figs. 3A and 3B is placed in the outer casing 2 in accordance with the arrangement shown in Fig. 4(A). In the diffuser disk 4 of the first embodiment, the inner diameter of the vent hole 431 positioned at the outermost periphery is set to 4 mm, and the inner diameter of the vent holes 432, 433, and 434 located radially inward of the first embodiment is set to 3.5. Mm.

In the second embodiment, the membrane module 1 having the same structure as that of the first embodiment is different except that the outermost peripheral vent 431 is smaller than that of the first embodiment. In the diffuser disk 4 of the second embodiment, the inner diameters of all the vent holes 431, 432, 433, and 434 were set to 3.5 mm.

In the comparative example, the air diffusion disk 204 shown in FIG. 4(B) is provided in the outer casing 2. In the diffuser disk 204 of this comparative example, the vent hole 431 of the outermost periphery of the diffuser disk 4 in the first embodiment is omitted, and only the vent holes 432, 433, and 434 which are located inside are provided. In the comparative example, the inner diameters of all the vent holes 432, 433, and 434 were set to 3.5 mm.

6A and FIG. 6B are the suspension member SS to the membrane member in the cycle of the backwashing step and the foaming step after the water treatment (filtration step) is performed for a predetermined period of time in each of the first embodiment, the second embodiment, and the comparative example. Comparison of the amount of adhesion of 3. One cycle for evaluation consists of a first water filling step, a filtration step, a back washing preparation step, a back washing step, a pressure releasing step, a second water filling step, a foaming step, and a draining step.

Specifically, the first water filling step is a step of preparing a water filling step of the filtering step and filling the inside of the outer casing 2 with raw water. The filtering step is a step of filtering the raw water supplied from the raw water inlet 11 into the outer casing 2 in the membrane module 1 and discharging it from the filtered water outlet 12. The backwash preparation step is a step of preparing a backwashing step. The backwashing step is a step of supplying air from the filtered water outlet 12 using the gas supply device 102. The pressure releasing step is a step of reducing the pressure in the filtered water outlet 12 which becomes a high pressure by performing the backwashing step. The second water filling step is a step of preparing a water filling step of the foaming step and filling the inside of the outer casing 2 with raw water. The foaming step is a step of supplying air from the gas supply port 14 into the outer casing 2 filled with the raw water using the gas supply device 102. The draining step is a step of draining the water in the outer casing 2 after the foaming step.

Regarding this evaluation, the time of each step in one cycle was set to be: first filling step 29 seconds, filtering step 600 seconds, back washing The preparation step is 2 seconds, the backwashing step is 10 seconds, the pressure relief step is 10 seconds, the second water filling step is 5 seconds, the foaming step is 60 seconds, and the drainage step is 20 seconds. Moreover, these conditions are used to facilitate the test, as opposed to the conditions used in the actual pipeline.

As shown in FIG. 6A and FIG. 6B, in the comparative example, the amount of adhesion of the suspended solids SS toward the film member 3 continued to increase with the elapsed time from the start of the evaluation to the end of the evaluation (about 7 days later). At the same time, the differential pressure in the membrane module 1 (the difference between the pressure on the side of the raw water inlet 11 and the pressure on the side of the filtered water outlet 12) also tends to increase.

In contrast, in Example 1 and Example 2, the amount of adhesion of the suspended matter SS to the film member 3 at the end of the evaluation was reduced to 1/4 of the comparative example as compared with the comparative example. In the first embodiment and the second embodiment, the amount of the suspended matter SS adhering to the film member 3 tends to increase at the initial stage of the evaluation, but the increase in the amount of adhesion after the intermediate stage of the evaluation is suppressed. In the first embodiment, the amount of the suspension SS adhered toward the film member 3 was further reduced as compared with the second embodiment. Further, in the first embodiment, the increase in the differential pressure was also suppressed as compared with the comparative example.

[Induction of Embodiments]

In the present embodiment, in the air diffusing disk 4 as the air diffusing member, a part of the plurality of vent holes 43 is disposed in such a manner as to be horizontally outward of the film member 3, and is backwashed. In the foaming step after the step, a part of the gas supplied into the membrane module 1 is guided to the upper side of the diffuser tray 4 by the vent hole 43 located on the outer side of the membrane member 3 in the horizontal direction. Further, this gas system can reach the suspended matter SS adhering to the outer peripheral portion 31 of the film member 3 by rising as in the liquid. Therefore, in the present embodiment, a part of the gas supplied into the membrane module 1 can be surely supplied to the membrane structure. The outer peripheral portion 31 of the member 3 allows the suspended matter SS adhering to the outer peripheral portion 31 of the film member 3 to be efficiently peeled off and removed from the surface of the film member 3.

In the present embodiment, the inner dimension in the horizontal direction of the outer casing 2 is larger than the horizontal dimension in the diffuser disk 4. Since the inner size of the outer casing 2 is larger than the size of the air diffusing disc 4, a gap is formed between the inner side surface of the outer casing 2 and the air diffusing disc 4. This gap functions as a passage for guiding the suspended matter SS peeled off from the film surface by the foaming step to the lower side of the diffuser disk 4. Thereby, the suspended matter SS removed from the surface of the film can be efficiently discharged outside the outer casing 2.

In the present embodiment, the inner diameter of the vent hole 43 provided on the outermost side in the horizontal direction among the plurality of vent holes 43 is larger than the inner diameter of the vent hole 43 provided on the inner side in the horizontal direction. Therefore, in the present embodiment, as compared with the case where the inner diameters of the plurality of vent holes 43 are the same, the ratio of the gas that is guided to the upper side of the diffuser disk 4 via the vent hole 43 at the outermost position in the horizontal direction can be increased. Thereby, the suspended matter SS adhering to the outer peripheral portion 31 of the film member 3 can be removed more efficiently.

In the present embodiment, the air diffusing disk 4 includes a disk-shaped main body portion 40, and a gas receiving portion 41 provided below the main body portion 40 for temporarily accommodating the gas supplied into the outer casing 2. The plurality of vent holes 43 are provided in the main body portion 40 in the horizontal direction outside the air receiving portion 41. The air receiving portion 41 has a plurality of dispersion holes 44 for dispersing the gas accommodated in the air receiving portion 41 in the horizontal direction outside the air receiving portion 41 below the main body portion 40. Therefore, the gas temporarily accommodated in the air receiving portion 41 is dispersed in the horizontal direction outside the air receiving portion 41 via the plurality of dispersion holes 44 provided in the air receiving portion 41. On the other hand, the body portion 40 is further than the air receiving portion 41 A plurality of vent holes 43 are provided on the outer side in the horizontal direction. Therefore, in the present embodiment, the ratio of the gas guided to the upper side of the diffuser disk 4 in the horizontal direction can be increased. In this configuration, since the gas is dispersed by the plurality of dispersion holes 44 provided in the air receiving portion 41, it is possible to suppress the gas from being deflected toward one of the plurality of vent holes 43 as compared with the case where the air receiving portion 41 is not provided. Share.

In the present embodiment, the hollow portion 5 extending in the vertical direction is formed on the inner side in the horizontal direction of the film member 3, and the air receiving portion 41 is provided below the main body portion 40 at a position corresponding to the hollow portion 5. In the present embodiment, the air receiving portion 41 is provided at a position corresponding to the hollow portion 5 where the supply gas is low. On the other hand, in order to supply the gas to the film member 3 which is horizontally outward of the hollow portion 5, the gas accommodated in the air receiving portion 41 is returned from the plurality of dispersion holes 44 to the air receiving portion 41. Dispersed laterally in the horizontal direction. Thereby, it is possible to efficiently supply the gas to the region where the supply gas is highly required, that is, to the outside of the horizontal direction of the air receiving portion 41. Further, in the hollow portion 5 formed inside the film member 3, for example, the support member 6 that supports the film member 3 can be disposed in the outer casing 2.

[Modification]

The embodiments of the present invention have been described above, but the present invention is not limited to the embodiments, and various modifications, improvements, and the like can be made without departing from the scope of the invention.

Fig. 7 is a schematic view showing a modification of the diffuser disk 4 in the membrane module 1 of the embodiment. The diffuser disk 4 of this modification has a plurality of auxiliary vent holes 45 provided in the peripheral wall portion 42 in an auxiliary manner. The plurality of auxiliary vent holes 45 are arranged at intervals in the circumferential direction of the peripheral wall portion 42. In this modification, the film module 1 is supplied to the film module 1 in the foaming step after the backwashing step. A portion of the gas inside is guided to the upper portion of the diffuser disk 4 by the auxiliary vent hole 45 located outside the film member 3 in the horizontal direction, and rises in the liquid to reach the outer peripheral portion attached to the film member 3. Suspension SS of 31.

In the above embodiment, the membrane module 1 is exemplified by a single-end fixed type (single-ended unconfined type) membrane module, and the membrane module 1 may also be the inner membrane member 3 of the outer casing 2 as shown in FIG. A membrane module with fixed ends at both ends. As shown in Fig. 8, the film module 1 of the both ends is provided with a casing 2, a film member 3, and a diffuser disk 4 as a diffusing member, and the diameter (horizontal dimension) in the diffuser disk 4 is larger than that of the film. The dimension of the member 3 from one side to the other side in the horizontal direction, a part of the plurality of vent holes 43 (the outermost peripheral vent hole 431) is positioned in a horizontal direction outside the film member 3 Settings. In addition, the characteristics of the size, positional relationship, and the like of the film member 3, the diffuser disk 4, the outer casing 2, and the like in the film module 1 of the both ends fixed type shown in FIG. 8 and the embodiment shown in FIGS. 1 to 5 Similarly, detailed descriptions are omitted.

In the above embodiment, the membrane module 1 is used for water treatment, but it is not limited thereto, and the membrane module 1 may be treated with a liquid that removes impurities in a liquid other than water.

In the above embodiment, the outer casing 2 has a cylindrical shape, but is not limited thereto, and may have other shapes.

In the above embodiment, the air diffusing member 4 is provided with the disk-shaped main body portion 40, the air receiving portion 41, and the peripheral wall portion 42, but is not limited thereto. In the air diffusing member 4, one or both of the air receiving portion 41 and the peripheral wall portion 42 may be omitted. Further, the main body portion 40 of the air diffusing member 4 is not limited to a disk shape, and may have other shapes such as a block shape.

In the above embodiment, the air diffusing member 4 is fixed to the outer casing 2 by the fixing member 7, but may be directly fixed to the outer casing 2 without using the fixing member 7. Further, the air diffusing member 4 may be fixed to the film member 3 without being fixed to the outer casing 2, for example.

In the above embodiment, the gas supplied into the outer casing 2 in the foaming step is air, but a gas other than air may be used in the foaming step.

Here, the above embodiment will be briefly described.

(1) In the above embodiment, a part of the plurality of vent holes in the air diffusing member is provided so as to be positioned outside the film member in the horizontal direction. Therefore, in the foaming step, a part of the gas supplied into the outer casing is guided to the upper side of the air diffusing member by the vent hole positioned outside the film member in the horizontal direction. This gas reaches the outer peripheral portion of the membrane member because it rises in the liquid. In this way, since a portion of the gas supplied into the membrane module can be surely supplied to the outer peripheral portion of the membrane member, the suspended matter adhering to the outer peripheral portion of the membrane member can be efficiently peeled off from the surface of the membrane member and Remove.

(2) Preferably, in the film module, a gap is formed between the outer casing and the air diffusing member.

In this configuration, a gap is formed between the outer casing and the air diffusion member by, for example, a configuration in which the inner size of the outer casing in the horizontal direction is larger than the size of the air diffusion member in the horizontal direction. This gap can be used as a function of guiding the suspension which is peeled off from the surface of the film by the foaming step to the passage below the diffusing member. Thereby, the suspended matter removed from the surface of the film can be efficiently discharged outside the casing.

(3) Preferably, in the film module, an inner diameter of the outermost vent hole among the plurality of vent holes is larger than an inner diameter of the vent hole provided on the inner side.

In this configuration, the vent hole positioned at the outermost side in the horizontal direction is provided so as to be positioned outside the film member in the horizontal direction. Further, in this configuration, the inner diameter of the vent hole positioned at the outermost side in the horizontal direction is set to be larger than the inner diameter of the vent hole provided on the inner side in the horizontal direction. Therefore, in this configuration, compared with the case where the inner diameters of the plurality of vent holes are the same, the ratio of the gas guided to the air diffusing member via the outermost vent holes is comparable to the vent holes passing through the inner side thereof. The proportion of gas is also increased. Therefore, with this configuration, the suspended matter adhering to the outer peripheral portion of the film member can be removed more efficiently than in the case where the inner diameters of the plurality of vent holes are the same.

(4) Preferably, in the film module, the air diffusion member includes a plate-shaped main body portion provided with the plurality of ventilation holes, and is provided below the main body portion for supply to the outer casing In the air receiving portion in which the gas is temporarily accommodated, the plurality of vent holes are provided on the main body portion in a horizontal direction outside the air receiving portion, and the air receiving portion has a gas that is stored in the air receiving portion in the body The lower portion of the portion is a plurality of dispersion holes dispersed in the horizontal direction from the air receiving portion.

In this configuration, the air receiving portion is provided below the main body portion of the air diffusing member, and the air system temporarily stored in the air receiving portion is further horizontally outward than the air receiving portion via the plurality of dispersing holes provided in the air receiving portion. dispersion. Then, the gas dispersed by the plurality of dispersed holes is guided to a plurality of vent holes provided on the outer side in the horizontal direction from the air receiving portion. Therefore, this constitutes In other words, it is possible to suppress the flow of the vent hole whose gas is directed to the inside as compared with the case where the air receiving portion is not provided.

(5) Preferably, in the film module, a hollow portion is formed in a horizontal direction inside the film member in a horizontal direction, and the air receiving portion is provided in the hollow portion by the body portion. Directly below.

In this configuration, the air receiving portion is disposed directly below the hollow portion by the main body portion, and the gas accommodated in the air receiving portion is dispersed from the plurality of dispersion holes to the outside of the air receiving portion in the horizontal direction. In other words, the air receiving portion is provided at a position (directly below the hollow portion) corresponding to the hollow portion where the supply of the gas is low. On the other hand, in order to preferentially supply the gas to the film member which is horizontally outward of the hollow portion, the gas contained in the air receiving portion is dispersed from the plurality of dispersion holes to the outside of the air receiving portion in the horizontal direction. Thereby, it is possible to efficiently supply the gas gas to the region where the supply gas is highly required, that is, to the outside of the horizontal direction from the gas receiving portion.

(6) The film module may be a single-end fixing type in which the upper end portion of the film member is fixed to the outer casing and the lower end portion of the film member is unconstrained. In the single-end type membrane module, the upper end portion of the membrane member is fixed to the upper portion of the support member, and the lower portion of the support member is fixed to the outer casing.

(7) The film module may be of a fixed end type, and the both end fixing type is such that both the upper end portion and the lower end portion of the film member are fixed to the outer casing.

(8) The film module may also have the film member The membrane module of the air filter membrane is externally filtered.

(9) Preferably, the first casing is provided with a first opening, and functions as a raw water inlet for supplying raw water in a filtering step, and functions as a discharge port in a foaming step of supplying a gas into the outer casing; The second opening functions as a filtered water outlet in the filtration step, and functions as a supply port for the cleaning fluid in the backwashing step. The first port is provided below the film member, and the second port may be provided above the film member.

(10) A gas supply port for supplying a gas into the outer casing may be provided in the outer casing. The gas supply port may be provided below the membrane member and the gas diffusion member.

(11) The air diffusing member may have a peripheral wall portion that extends downward from a peripheral edge of the main body portion. The plurality of dispersion holes may be provided at a position higher than the lower end of the peripheral wall portion.

(12) The interval between the outermost vent holes among the plurality of vent holes may be narrower than the interval between the vent holes disposed radially inward of the plurality of vent holes.

(13) The interval between the innermost vent holes among the plurality of vent holes may be wider than the interval between the vent holes disposed radially outward of the plurality of vent holes.

(14) A fixing member that fixes the air diffusing member to the outer casing may be provided.

According to the above embodiment, it is possible to efficiently remove the adhesion to the film module used for the liquid treatment for removing impurities in the liquid. A suspension of the peripheral portion of the membrane member.

2‧‧‧ Shell

204‧‧‧Distribution plate

3‧‧‧membrane components

31‧‧‧The outer part

4‧‧‧Distribution plate

40‧‧‧ Body Department

41‧‧‧Air Department

42‧‧‧Walls

43, 431, 432‧‧ vents

A, A1, A11‧‧ Center

D1‧‧‧Diameter (the horizontal dimension in the diffuser 4)

D11‧‧‧ diameter

D2‧‧‧ size

D3‧‧‧ Inner diameter (inner dimension in the horizontal direction of the outer casing 2)

G‧‧‧ gap

Claims (14)

A membrane module comprising: a casing; a membrane member disposed in the casing; and a diffusing member having a plurality of vent holes disposed under the membrane member in the casing for supplying gas to the membrane member, The size of the air diffusing member in the horizontal direction is larger than the size of the film member in the horizontal direction, and a part of the plurality of vent holes is disposed in such a manner as to be located outside the horizontal direction of the film member. . The membrane module of claim 1, wherein a gap is formed between the outer casing and the air diffusing member. The membrane module of claim 1, wherein an inner diameter of the outermost vent hole among the plurality of vent holes is larger than an inner diameter of the vent hole provided at an inner side thereof. The membrane module according to any one of claims 1 to 3, wherein the gas diffusion member comprises: a plate-shaped body portion provided with the plurality of vent holes; and an air receiving portion provided on a lower side of the body portion The plurality of vent holes are temporarily disposed outside the horizontal direction of the air receiving portion, and the air receiving portion has a plurality of discrete holes for the gas to be supplied into the outer casing. The gas accommodated in the air receiving portion is dispersed outside the main body portion in the horizontal direction from the air receiving portion. The membrane module according to claim 4, wherein a hollow portion extending in the vertical direction is provided inside the horizontal direction of the membrane member, and the gas receiving portion is provided directly below the hollow portion by the body portion. The membrane module according to any one of claims 1 to 3, wherein the upper end portion of the membrane member is fixed to the outer casing, and the lower end portion of the membrane member is a single-end fixed type in an unconstrained state. The membrane module according to any one of claims 1 to 3, wherein both the upper end portion and the lower end portion of the membrane member are fixed at both ends to the outer casing. The membrane module according to any one of claims 1 to 3, wherein the membrane member is a membrane module having an external pressure filtration method of a hollow fiber membrane. The membrane module according to any one of claims 1 to 3, wherein the outer casing is provided with a first opening, which functions as a raw water inlet for supplying raw water in the filtering step, and functions as a discharge port in the foaming step. The function and the second opening function as a filtered water outlet in the filtering step, and function as a supply port for the cleaning fluid in the backwashing step, and the first opening is provided on the membrane member. Below, the second port is provided above the film member. The membrane module according to any one of claims 1 to 3, wherein the outer casing is provided with a gas supply port for supplying a gas into the outer casing, The gas supply port is provided below the membrane member and the gas diffusion member. The membrane module according to claim 4, wherein the diffusing member has a peripheral wall portion extending downward from a peripheral edge of the main body portion, and the plurality of dispersing holes are provided at a position higher than a lower end of the peripheral wall portion. The membrane module according to any one of claims 1 to 3, wherein a space of the outermost vent holes among the plurality of vent holes is spaced apart from each other by a vent hole disposed radially inward of the plurality of vent holes Still narrow. The membrane module according to any one of claims 1 to 3, wherein a space of the innermost vent holes among the plurality of vent holes is spaced apart from each other by a vent hole disposed radially outward of the plurality of vent holes Still wide. The film module according to any one of claims 1 to 3, wherein a fixing member for fixing the air diffusing member to the outer casing is provided.