JP3941100B2 - Membrane separator - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a membrane separation apparatus, and more particularly to an immersion flat membrane type membrane separation apparatus used in the field of wastewater treatment.
[0002]
[Prior art]
An immersion flat membrane type membrane separation apparatus immerses a membrane element having a filtration membrane in a liquid to be treated, sucks the liquid to be treated into the membrane element, and allows the liquid to be treated to pass through the filtration membrane. It is an apparatus that performs liquid separation processing. The membrane element is usually configured by overlaying a filtration membrane on the surface of a plate-like support material having liquid permeability and adhering the filtration membrane to the outer peripheral portion of the support material. The membrane element configured as described above is immersed in the liquid to be processed in an upright state, and a plurality of membrane elements are arranged in parallel at a predetermined interval. Air diffuser is provided below the membrane element. By performing air diffuse from the air diffuser, the diffused air rises between the membrane elements and swings the filter membrane. Peel the cake attached to the. Thereby, obstruction | occlusion of a filtration membrane can be suppressed and high filtration efficiency can be maintained.
[0003]
[Problems to be solved by the invention]
However, the conventional membrane separation apparatus has a problem that when the membrane element is immersed in the liquid to be treated, the air in the membrane element moves upward to form an air pocket, and the upper part of the filtration membrane swells outward. . For this reason, the upper part of the filtration membrane may be peeled off from the support material, or may be rubbed with the adjacent filtration membrane to damage the filtration membrane. In addition, when adjacent filtration membranes come into contact with each other, there is a possibility that the gap between the filtration membranes disappears and aeration air cannot pass, and the filtration membranes are rapidly blocked.
[0004]
The present invention has been made in view of such circumstances, and an object of the present invention is to provide a membrane separation device that can prevent a membrane of a membrane element from greatly expanding outward.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, the present invention immerses a liquid to be processed in a state where a membrane element formed by adhering a filtration membrane to the surface of a plate-like support material having liquid permeability is provided, In the membrane separation apparatus that performs solid-liquid separation, the adhesive material that bonds the support material and the filtration membrane is applied in a straight line in the horizontal direction, and is arranged in a plurality of stages at predetermined intervals in the vertical direction. The gap between the adhesives is characterized in that the gap at the upper part of the membrane element is narrower than the gap at the lower part.
[0006]
According to the present invention, since the filtration membrane is bonded at a plurality of locations in the vertical direction, even if the membrane element is immersed in the liquid to be treated, the filtration membrane does not swell unevenly in a part in the vertical direction. Further, according to the present invention, since the gap between the adhesives is narrowed at the upper part of the filtration membrane where the filtration membrane tends to bulge, the bulge of the filtration membrane can be evenly dispersed. Therefore, it is possible to prevent the filtration membrane from being greatly expanded locally.
[0007]
In addition, according to the present invention, since the gap between the adhesives is widened at the lower part of the filtration membrane, a large amount of backwash liquid easily flows to the lower part of the filtration membrane during the backwashing. Therefore, the lower part of the filtration membrane to which a large water pressure is applied can be reliably backwashed.
[0008]
Furthermore, according to the present invention, since the adhesive is formed in a straight line, the effective membrane area of the filtration membrane can be sufficiently ensured.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of a membrane separation apparatus according to the present invention will be described in detail with reference to the accompanying drawings.
[0010]
As shown in FIG. 1, a membrane separation apparatus 1 according to the present invention is mainly composed of a tank 3 in which a liquid 2 to be treated is stored and a membrane module 10 immersed in the liquid 2 to be treated. The membrane module 10 is connected to the pump 4, and the inside of the membrane module 10 is decompressed by the pump 4. Further, around the membrane module 10, an aeration guide wall 5 having openings at the top and bottom is disposed so as to surround the membrane module 10.
[0011]
A diffuser tube 6 is disposed below the membrane module 10. The air diffuser 6 has innumerable air diffuser holes on the surface thereof, is connected to the blower 7, and air is supplied from the blower 7. Thereby, air is blown out into the liquid 2 to be processed from the air diffuser of the air diffuser 6. The blown-out air rises in the liquid 2 to be treated, swings the membrane surface of the membrane module 10 to peel the cake attached to the membrane surface, and stirs the inside of the tank 3.
[0012]
FIG. 2 is a perspective view showing the structure of the membrane module 10. As shown in the figure, the membrane module 10 is mainly composed of a plurality of sets of membrane elements 11 arranged in parallel, and membrane bonding fixing members 24 and 26 that support the left and right ends of the membrane element 11. The membrane bonding fixing materials 24 and 26 are made of a resin such as PVC, and water collecting pipes 24a and 26a are formed therein. The water collecting pipes 24 a and 26 a are communicated with the hollow portion 20 a (see FIG. 3) of the membrane end fixing material 20 and are connected to the pump 4 of FIG. 1 through the water collecting pipes 28 and 30. Therefore, the inside of each membrane element 11 can be decompressed by driving the pump 4.
[0013]
Each membrane element 11 is configured by attaching a filtration membrane 12 to the surface of a water-permeable material 16 via a spacer 14. The filtration membrane 12 is made of an organic flat membrane, and the spacer 14 is made of a breathable material such as a nonwoven fabric. Further, as shown in FIG. 3, the water-permeable material 16 is obtained by adding a porous plate 16b having holes 16c to both surfaces of a base material 16a having a corrugated cross section. By the base material 16a and the porous plate 16b, A plurality of independent water passages 18 extending in the height direction are defined. The water-permeable material 16 may be a porous body such as a plastic stage. Further, the water-permeable material 16 and the spacer 14 may be integrated. Hereinafter, the water-permeable material 16 and the spacer 14 are collectively referred to as the support material 13.
[0014]
As shown in FIG. 2, membrane end fixing materials 20 and 22 are attached to the upper and lower end portions of the membrane element 11, and the end portions of the membrane element 11 are reinforced. The upper membrane end fixing member 20 is formed in a hollow shape as shown in FIG. 3, and the hollow portion 20a of the membrane end fixing member 20 is communicated with the water collecting pipes 28 and 30 shown in FIG. The lower membrane end fixing member 22 may be formed in a hollow shape and communicated with the water collecting pipes 28 and 30.
[0015]
Comb-like intermembrane holding materials 32 and 34 are attached to the membrane edge fixing materials 20 and 22, and the membrane element 11 is held at a predetermined interval, for example, 5 to 10 mm.
[0016]
4 and 5 are a front view and a side sectional view showing the support member 13 and the filtration membrane 12 of the membrane element 11.
[0017]
As shown in these drawings, the support material 13 and the filtration membrane 12 are bonded together by an adhesive material 36. The adhesive 36 is applied in a straight line in the horizontal direction, and is arranged in a plurality of stages with a predetermined interval in the vertical direction. Further, the interval between the adhesives 36 and 36 is configured so as to be narrower toward the top. That is, when the interval between the adhesives 36 and 36 is set to L1 to L6 from the top, L1 <L2 <L3 <L4 <L5 <L6.
[0018]
Further, the distances L1 to L6 between the adhesive materials 36 and the width W of the adhesive material 36 are values that can sufficiently secure the adhesive strength and the effective film area. Below, the result of having examined the width W and the distances L1-L6 of the adhesive material 36 is demonstrated.
[0019]
FIG. 5 shows the result of study on the width W of the adhesive 36. As shown in the figure, as the width W of the adhesive 36 increases, the effective membrane area decreases and the processing capability of the filtration membrane 12 decreases. Therefore, the width W of the adhesive 36 is preferably 10 mm or less that satisfies the allowable effective membrane area.
[0020]
Further, as the width W of the adhesive 36 decreases, the adhesive strength decreases, and the filtration membrane 12 is easily peeled off from the support material 13. Therefore, the width W of the adhesive 36 is preferably 0.5 mm or more that satisfies the allowable adhesive strength.
[0021]
FIG. 6 is a result of studying the interval when the adhesive material 36 is provided at a constant interval. As shown in the figure, as the distance between the adhesives 36 increases, the adhesive strength decreases and the filtration membrane 12 is easily peeled off from the support material 13. Therefore, the interval between the adhesives 36 is preferably 500 mm or less that satisfies the allowable adhesive strength.
[0022]
Further, as the distance between the adhesives 36 is reduced, the effective membrane area is reduced, and the processing capability of the filtration membrane 12 is reduced. Therefore, it is preferable that the space | interval of the adhesive material 36 shall be 15 mm or more which satisfy | fills an allowable effective membrane area.
[0023]
As described above, the width W of the adhesive 36 is preferably set to 0.5 mm or more and 10 mm or less, and the intervals L1 to L6 of the adhesive 36 are preferably set to 15 mm or more and 500 mm or less. It can be seen that sufficient strength and effective membrane area can be secured. Note that the distances L1 to L6 between the adhesives may be L1 <L2 <L3 <L4 <L5 <L6 within a range of 15 mm to 500 mm.
[0024]
Next, the operation of the membrane separation apparatus 1 configured as described above will be described.
[0025]
When the pump 4 is driven, the inside of the membrane element 11 of the membrane module 10 becomes negative pressure, and the liquid 2 to be treated is sucked into the membrane element 11. At that time, the liquid to be treated 2 passes through the filtration membrane 12, so that solids such as SS contained in the liquid to be treated 2 are collected in the filtration membrane 12, and solid-liquid separation processing is performed. At that time, since the filtration membrane 12 is gradually blocked, regular backwash cleaning is required. The backwash cleaning is performed by stopping the pump 4 or supplying a chemical solution to the inside of the membrane element 11, and the cake adhered to the filtration membrane 12 is peeled off when the fluid flows in a direction opposite to that during filtration.
[0026]
By the way, when backwashing is performed or when the membrane element 11 is immersed in the liquid 2 to be treated, the filtration membrane 12 tends to swell outward. In particular, the upper part of the filtration membrane 12 tends to bulge outward because the water pressure is low and an air pocket is formed. However, in the present embodiment, since the adhesive 36 for bonding the support member 13 and the filtration membrane 12 is formed in a straight line in the horizontal direction and provided in a plurality of stages in the vertical direction, the filtration membrane 12 is provided in the vertical direction. Are bonded at a plurality of locations. Therefore, it is possible to prevent the filtration membrane 12 from being locally biased and swollen in a part in the vertical direction.
[0027]
Moreover, in this Embodiment, since the space | interval of the adhesive materials 36 was narrowed as it became upper part from the lower part, the swelling of the filtration membrane 12 can be disperse | distributed equally. That is, the filtration membrane 12 is more likely to swell as it becomes upper due to factors such as air accumulation and water pressure. However, the upper portion of the filtration membrane 12 is evenly swelled in the vertical direction by narrowing the interval between the adhesives 36 to prevent it from swelling. Can be distributed. Thereby, it can prevent that the upper part of the filter membrane 12 expands locally locally.
[0028]
Moreover, since the membrane separation apparatus 1 of this Embodiment expands, so that the space | interval of the adhesive materials 36 becomes lower, backwashing can be performed effectively. That is, when backwashing is performed, the lower part of the filtration membrane 12 has a high water pressure, so the backwash flow rate is reduced and the cleaning effect is reduced. However, in the present embodiment, the lower the filtration membrane 12, the wider the gap between the adhesives 36 and the easier the backwash liquid flows, so the lower portion of the filtration membrane 12 can also be backwashed effectively.
[0029]
Furthermore, according to the membrane separation apparatus 1 of the present embodiment, since the adhesive 36 is formed in a straight line, the effective membrane area of the filtration membrane 12 can be sufficiently ensured. In particular, since the gap between the adhesives 36 is widened at the lower part of the filtration membrane 12, the effective membrane area of the filtration membrane 12 can be sufficiently ensured. Therefore, it is possible to prevent the filtration membrane 12 from expanding outward while maintaining high filtration efficiency.
[0030]
In the above-described embodiment, a plurality of sets of membrane elements 11 are assembled to form the membrane module 10. However, each membrane element 11 may be provided with a water collection port and installed one by one.
[0031]
In the above-described embodiment, an organic flat membrane is used as the filtration membrane 12, but a metal membrane may be used and the filtration membrane 12 and the support material 13 may be welded. In that case, welding may be performed linearly in the horizontal direction and at a predetermined interval in the vertical direction. Also, the welding interval should be made narrower toward the top.
[0032]
Furthermore, although embodiment mentioned above formed the space | interval of the adhesive materials 36 narrower as the upper part, it is not limited to this. For example, even if the intervals between the adhesives 36 are equal, the filtration membrane 12 is bonded at a plurality of locations in the vertical direction, so that an effect of suppressing the filtration membrane 12 from locally expanding can be obtained.
[0033]
【The invention's effect】
As described above, according to the membrane separation apparatus according to the present invention, the adhesive for bonding the support material and the filtration membrane is formed in a straight line in the horizontal direction, and is provided in a plurality of stages at predetermined intervals in the vertical direction. Therefore, the filtration membrane is bonded at a plurality of locations in the vertical direction. Therefore, it is possible to prevent the filtration membrane from swelling partially in the vertical direction. Further, according to the present invention, since the gap between the adhesives is narrowed at the upper part of the filtration membrane where the filtration membrane tends to bulge, the bulge of the filtration membrane can be evenly dispersed. In addition, according to the present invention, since the gap between the adhesives is widened at the lower part of the filtration membrane, a large amount of backwash liquid easily flows to the lower part of the filtration membrane during backwashing, and the lower part of the filtration membrane is reliably backwashed. can do. Furthermore, according to the present invention, since the adhesive is formed in a straight line, the effective membrane area of the filtration membrane can be sufficiently ensured. Thereby, the swelling of the filtration membrane can be prevented while maintaining high filtration efficiency.
[Brief description of the drawings]
FIG. 1 is a schematic view showing the structure of a membrane separation apparatus according to the present invention. FIG. 2 is a perspective view showing the structure of a membrane module. FIG. 3 is a perspective view showing the structure of a membrane element. FIG. 5 is a side cross-sectional view of the membrane element filtration membrane and the support material. FIG. 6 is a diagram showing the results of the study on the width of the adhesive. FIG. 7 is a study result on the spacing between the adhesives. Figure showing symbols [Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Membrane separator, 2 ... Liquid to be treated, 3 ... Tank, 4 ... Pump, 5 ... Air diffusion guide wall, 6 ... Air diffuser, 7 ... Blower, 10 ... Membrane module, 11 ... Membrane element, 12 ... Filtration membrane DESCRIPTION OF SYMBOLS 13 ... Support material, 14 ... Spacer, 16 ... Water flow material, 16a ... Base material, 16b ... Perforated plate, 18 ... Water flow path, 20 ... Membrane edge fixing material, 22 ... Membrane edge fixing material, 24 ... Membrane bonding fixation 26 ... Membrane bonding fixing material, 28 ... Water collecting pipe, 30 ... Water collecting pipe, 32 ... Intermembrane holding material, 34 ... Intermembrane holding material, 36 ... Adhesive

Claims (3)

In a membrane separation apparatus that immerses in a liquid to be treated in a state where a membrane element formed by adhering a filtration membrane to the surface of a plate-like support material having liquid permeability is installed, and performs solid-liquid separation of the liquid to be treated.
The adhesive material that bonds the support material and the filtration membrane is applied in a straight line in the horizontal direction, and is arranged in a plurality of stages with a predetermined interval in the vertical direction. A membrane separation device characterized in that the gap at the upper part of the membrane element is narrower than the gap at the lower part. The membrane separator according to claim 1, wherein a width of the adhesive is 0.5 to 10 mm. The membrane separation apparatus according to claim 1 or 2, wherein a distance between the adhesives is 15 to 500 mm.

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