JPH09108546A - Rotary type membrane separator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase circulation flow in the direction of a rotary shaft and to obtain sufficient reduction effect of concentration polarization by providing a through-hole near the rotary shaft of a rotary flat membrane and providing flow paths on the side of an inner wall in the axial direction of a casing and in the end face of the inner wall to lead raw liquid to be treated in the casing to the through-hole part. SOLUTION: Amount of raw liquid to be treated which passes in the thickness direction through the rotary flat membranes 14 is increased by circulation flow. Raw liquid to be treated is filtered by passing it through the rotary flat membranes 14. Filtrate is discharged to a filtrate tank through flow paths of filtrate of respective rotary flat membranes 14, the flow path 16a of a supporter 16, a communicating path 15 between flanges 12, 13 and the flow path 6a of a rotary shaft 6. In such a way, since a baffle plate 9 is provided along the axial direction on the side of the inner wall of a casing 2 in a membrane separator 1 and the flow path is formed, circulation flow of raw liquid to be treated in the axial direction is made plenty and shearing force is strengthened and concentration polarization is reduced.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to microfiltration, ultrafiltration, nanofiltration (low pressure reverse osmosis method), membrane distillation, pervaporation (pervaporation method), etc.
The present invention relates to a separation apparatus that processes a stock solution to be treated, such as filtration and evaporation, and particularly relates to a rotary membrane separation apparatus that uses a rotary flat membrane.

[0002]

2. Description of the Related Art Conventionally, in order to treat a highly concentrated stock solution to be treated, a membrane separation apparatus for treating with low power has been used.
In this membrane separation device, a plurality of disc-shaped rotary flat membranes are arranged in the rotation axis direction, and by rotating the rotary flat membranes, the stock solution to be treated is filtered and processed. The stock solution to be treated circulates around the rotary flat membrane, the flow of the stock solution to be treated is weak, the concentration polarization cannot be reduced so much, and the filtration efficiency is lowered. Therefore, as disclosed in Japanese Patent Application Laid-Open No. 1-139114 and Japanese Patent Publication No. 7-41148, a through hole is provided in the central portion of the rotary flat film to promote the flow of the stock solution to be treated and reduce the concentration polarization. I am trying to let you.

[0003]

However, in the membrane separation device having the through hole in the central portion of the rotary flat membrane, the rotary flat membrane is simply provided with the through hole. There is a problem that the circulating flow (secondary flow) of the stock solution to be treated flowing in the through hole in the axial direction does not have sufficient strength, and the effect of reducing concentration polarization cannot be sufficiently obtained.

That is, due to the rotation of the rotary flat membrane, the undiluted solution to be treated in the casing is dominated by the flow flowing in the circumferential direction, flowing axially on the outer peripheral side of the rotary flat membrane and flowing into the through hole. The stock solution is very small. As a result, the flow rate of the undiluted solution to be treated passing through the rotary flat membrane becomes small, and the concentration polarization cannot be sufficiently reduced.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a rotary membrane separation device capable of increasing the circulation flow in the direction of the rotation axis and obtaining a sufficient concentration polarization reducing effect. To provide a device.

[0006]

In order to achieve the above object, the rotary membrane separator according to claim 1 is a rotary membrane separator in which a plurality of disk-shaped rotary flat membranes are arranged on a rotary shaft in a casing. In the device, a through hole is provided in the vicinity of the rotation axis of the rotary flat film, and a flow path for guiding the untreated liquid in the casing to the through hole portion is formed on at least one of the inner wall side surface and the inner wall end surface of the casing in the axial direction. It is characterized in that a flow path forming means is provided. Further, in the rotary membrane separation device according to claim 2, the flow path forming means is a ridge,
The rotary membrane separator according to claim 3 is characterized in that the flow path forming means is a groove.

According to these rotary membrane separators, for example, the circulation passages are formed by the protrusions or grooves provided on the side surface of the inner wall in the axial direction of the casing where the flow in the rotational direction is dominant and the pressure is high. From this circulation flow path, a circulation flow leading to a through-hole of the rotating flat membrane having a low pressure is generated, and this circulating flow is strengthened by suppressing the flow in the rotating direction by the protrusions, etc. The flow rate also increases. Due to the increase in the flow rate flowing through the rotary flat membrane, the angular momentum of the stock solution to be treated, which was circling between the rotary flat membranes, was decreased, and the relative speed between the rotary flat membrane and the stock solution to be treated between the rotary flat membranes was increased. The velocity gradient becomes large, the shearing force becomes strong, and the effect of sufficiently reducing the concentration polarization can be obtained.

The rotary membrane separator according to a fourth aspect of the present invention is a rotary membrane separator in which a plurality of disk-shaped rotary flat membranes are arranged on a rotary shaft in a casing, and the rotary flat membrane is provided in the vicinity of the rotary shaft of the rotary flat membrane. In addition to providing the through hole, a communication passage communicating from the outer peripheral wall of the casing to the through hole portion of the rotary flat membrane is provided outside the casing. According to this rotary membrane separator, the stock solution is reliably supplied to the central portion of the rotary flat membrane by the communication passage outside the casing, the circulating flow in the axial direction is strengthened, and the concentration polarization is sufficiently reduced. can get.

[0009]

Embodiments of the present invention will be described below in detail with reference to the drawings. 1 and 2 show a first embodiment of the rotary membrane separation device according to the present invention, FIG. 1 is a longitudinal sectional view thereof, and FIG. 2 is a view taken along the line AA of FIG. In the figure, a membrane separation device 1 has a casing 2 and a membrane separation means 3, the casing 2 is formed in a substantially cylindrical shape, and one end face 2a thereof is open, and a lid 4 is provided in this opening. It is attached. Also, the other end surface 2b of the casing 2
A shaft sealing hole 5 is formed at the center position of the shaft, and a shaft sealing member 7 through which the rotary shaft 6 is inserted is attached to the shaft sealing hole 5.

The side surface 2 which is the outer peripheral surface of the casing 2
c is provided with an inflow port 8 for allowing the stock solution to be treated to flow into the casing 2, and the inner surface of the side surface 2c (the inner wall side surface S
Is attached with a baffle plate 9 as a flow path forming means along the axial direction. Six baffle plates 9 are formed in a flat plate shape and are fixed at equal positions in the circumferential direction of the casing 2 so as to project toward the center of the casing 2. A circulation channel for generating a circulation flow described later is formed on the outer peripheral side of the.

The membrane separating means 3 has the rotary shaft 6 and a plurality of rotary flat membranes 14 arranged at the end of the rotary shaft 6 via a pair of flanges 12 and 13. Flange 1
2 and 13 are each formed in a disk shape, one flange 12 is fixed to an end portion of the rotary shaft 6 having a flow path 6a therein, and the other flange 13 is a communication passage between the flange 12 and the flange 12. It is fixed to the flange 12 with 15 formed. Then, four columns 16 are fixed to the outer peripheral edge of the flange 13, and a plurality of rotary flat membranes 1 are attached to the columns 16.
4 are attached at predetermined intervals.

That is, four mounting holes 17 are formed in the outer peripheral edge of the rotary flat film 14, and each mounting hole 17 is provided on four columns 16, an end sealing member 18, an intermediate spacer 19, The rotary flat membrane 14 is attached to the column 16 at predetermined intervals by inserting the end seal member 20 and screwing a nut 21 (for example, a double nut) into a screw 16b provided at the end of the column 16. ing.

The rotary flat membrane 14 is, for example, a disc-shaped support substrate (not shown), a filtration membrane 23 (see FIG. 2) covering both side surfaces of the support substrate, and a filtrate flow formed on the support substrate. There is a passage (not shown) and the like, and a hole 14a is formed in the central portion thereof. By arranging a plurality of the rotary flat membranes 14 at a predetermined interval, the holes 14a are located on a straight line, and the through holes 24 are formed to axially penetrate the central portion of the membrane separating means 3. .

The pillar 16 is hollow with one end side (flange 13 side) opened and has a flow channel 16a formed therein. The flow channel 16a is formed by the flange 12,
It communicates with the flow path 6 a of the rotary shaft 6 via a communication passage 15 between the shafts 13. Further, O-rings 25 are interposed at the contact portions between the end seal members 18, 20 and the intermediate spacer 19 and each rotary flat film 14.

The membrane separation device 1 operates as follows. That is, the untreated liquid is supplied from the inflow port 8 into the casing 2 by a pump (not shown) to substantially completely fill the casing 2, and a motor (not shown) connected to the rotating shaft 6 is operated to rotate the rotating shaft 6 Rotate. When the rotary shaft 6 rotates, the rotary flat membrane 14 rotates via the flanges 12 and 13 and the support 16 to stir the stock solution to be treated in the casing 2.

At the time of stirring the stock solution to be treated, the rotary flat film 14
The stock solution to be treated which is interposed between the rotating flat membranes 14 flows from the central side toward the outer peripheral side by the centrifugal force due to the rotation of
That is, a projecting flow that flows so as to project from between the rotary flat membranes 14 toward the inner wall side surface S of the casing 2 is generated, and the pressure on the center side of the rotary flat membranes 14 is low and the outer peripheral side is high. In addition, in the inner wall side surface S portion of the casing 2, a flow of the stock solution to be treated in the rotation direction (circumferential direction) is about to be generated,
This flow is regulated by the baffle plate 9 provided on the inner wall side surface S, and becomes a flow along the longitudinal direction of the baffle plate 9 after contacting the baffle plate 9.

This flow comes into contact with the inner surface (referred to as the inner wall end surface T) of the lid 4 of the casing 2 and flows into the through hole 24 on the central side of the rotary flat membrane 14 where the pressure is low, and the stock solution to be treated is treated. Flows in the casing 2 as shown by the arrow A in FIG. 1, and a circulating flow that circulates in the casing 2 in the axial direction (axial direction of the rotary shaft 6) is generated. This circulating flow becomes stronger because the baffle plate 9 reduces the amount of the liquid to be processed flowing in the inner wall side surface S of the casing 2 in the circumferential direction. As a result, a large amount of the stock solution to be treated having a small angular velocity flows between the rotary flat membranes 14, and the angular momentum of the liquid to be treated that has been circulated between the rotary flat membranes 14 is reduced, so that the rotary flat membranes 14 and the rotary flat membranes 14 are The relative velocity between the membrane 14 and the stock solution to be treated is increased, the velocity gradient is increased, and the shearing force is increased.

Then, by this circulating flow, the rotating flat film 14
The amount of the stock solution to be treated that passes through in the thickness direction increases, and the filtrate filtered by passing through the rotary flat membrane 14 is
The filtrate flow path of each rotary flat membrane 14, the flow path 16a of the column 16, the communication path 15 between the flanges 12 and 13, the flow path 6a of the rotary shaft 6.
Through a liquid tank to a filtrate tank (not shown).

As described above, according to the membrane separation apparatus 1 of the above-mentioned embodiment, the baffle plate 9 is arranged along the axial direction on the side surface S of the inner wall of the casing 2 to form the flow path. The circulating flow of the stock solution in the axial direction can be increased, the shearing force becomes stronger, and the concentration polarization can be reduced. Also, the baffle plate 9
For example, it is sufficient to fix the lid 4 to the inner wall side surface S of the casing 2 with the lid 4 removed from the opening of the casing 2,
The structure is simplified and, for example, the existing rotary flat film 14 is used.
It can be easily applied to a membrane separation device having a through hole near the rotation axis.

FIG. 3 is a graph obtained by an experiment regarding the relationship between the permeation flux and the perimeter velocity of the membrane in the first embodiment. The experiment was conducted under the following conditions, and in FIG. 3, the curve a indicates the first baffle plate 9 and the through hole 24 described above.
In the case of the embodiment, the curve b shows the case of the conventional example where there is no baffle plate 9 and the through hole 24, and the curve c shows the case where there is neither the baffle plate 9 nor the through hole 24.

Conditions: Casing inner diameter of about 355 mm, baffle height of 20 mm, 6 places installed on the circle in 6 equal parts, rotating flat membrane, membrane size: 300 mm, number of sheets, 6 sheets, membrane interval of 5 mm, material: polyethersulfone ultrafiltration membrane Permeation flux 84 l / m ² · h Permeable liquid to be permeated Polyethylene glycol aqueous solution Operating pressure 0.1 MPa

From this FIG. 3, it becomes clear that in the case of the first embodiment, the permeation flux of the stock solution to be treated which passes through the rotary flat film 14 is approximately doubled as compared with the conventional example, As a result, it has been confirmed that the concentration polarization can be sufficiently reduced.

4 and 5 show a modified example of the baffle plate shown in the first embodiment. In FIG. 4, the baffle plate is not a flat plate shape, but an inclined surface is provided on one side in the rotation direction. It is provided. The same parts as those in the first embodiment are designated by the same reference numerals, and detailed description thereof will be omitted (the same applies to the following embodiments). Baffle plate 2 shown in FIG.
7 makes the upstream side of the rotary flat film 14 in the rotational direction (b) substantially vertical to the inner wall side surface S of the casing 2, and forms a substantially arcuate inclined surface 27a on the downstream side in the rotational direction (b).
Due to the inclined surface 27a, the flow of the stock solution to be processed between the flow paths formed by the baffle plates 27 becomes smooth. In addition,
Although the baffle plate 27 is integrally molded with the casing 2, it may be formed as a separate body, and the inclined surface 27a may be formed not only in an arc shape but also in a linear shape.

The baffle plate 28 shown in FIG. 5 is fixed to the inner wall side surface S of the casing 2 by twisting the casing 2 in the axial direction. That is, the baffle plate 28 is fixed in a spiral shape that is twisted in the direction opposite to the rotation direction of the rotary flat film 14, and is positively moved in the axial direction of the through hole 24 of the rotary flat film 14 (direction of arrow C in FIG. 5). Generate a circulating flow. This baffle 2
The case of 8 is effective when the flow-through hole is not opened in the flange 13, which is the mounting shaft end side of the rotary flat film 14. It is apparent that the same effect as that of the first embodiment can be obtained by each of the baffles 27 and 28.

6 and 7 show a second embodiment of the rotary membrane separation device according to the present invention, FIG. 6 is a longitudinal sectional view thereof, and FIG. 7 is a view taken along the line BB of FIG. . The feature of this second embodiment is that a recessed groove 31 is formed on the inner wall side surface S of the casing 2 instead of the baffle plate 9 of the first embodiment.

That is, by projecting the side surface 2c of the casing 2 to the outside, a groove 31 is formed on the inner wall side surface S along the longitudinal direction of the side surface 2c. This groove 31 is the same as in the first embodiment. Six places are formed at equal intervals in the circumferential direction. Also in the second embodiment, the groove 31 restricts the flow of the stock solution to be treated in the rotating direction b of the rotary flat film 14, and the inside of the groove 31 and the space between the grooves 31 are indicated by the arrow D in FIG. A circulating flow of the stock solution to be treated is generated, and the same effects as those of the first embodiment can be obtained.

8 and 9 show a third embodiment of the rotary membrane separation device according to the present invention, FIG. 8 is a longitudinal sectional view thereof, and FIG. 9 is a view taken along the line CC of FIG. . The feature of the third embodiment is that baffle plates are provided on the inner wall side surface S and the inner wall end surface T of the casing, respectively. That is, the baffle plate 36 is fixed to the inner surface S of the side wall, and the baffle plate 37 is fixed to the inner surface of the lid 4 which is the inner wall end surface T while being continuous with the baffle plate 36. The length of the baffle plate 37 is set so that the inner end thereof is substantially the same as the outer edge of the hole 14a (through hole 24) of the rotary flat film 14, and the pair of baffle plates 36 and 37 are shown in FIG.
As shown in FIG.
A set is provided.

According to the third embodiment, the baffle plate 37 also forms a circulation channel on the inner surface of the lid 4, and the baffle plate 36,
The circulating flow path formed by 37 allows the stock solution to be processed to flow as shown by the arrow E in FIG. 8, and the amount of the stock solution to be processed flowing through the through holes 24 of the rotary flat film 14 can be further increased.
The same effect as that of each of the above embodiments can be obtained.

10 and 11 show a fourth embodiment of the rotary membrane separation device according to the present invention, FIG. 10 is a longitudinal sectional view thereof, and FIG. 11 is a view taken along the line DD of FIG. . This fourth
The feature of the embodiment is that the baffles 36 and 37 of the third embodiment are replaced with grooves 39 and 40. That is, the groove 39 is provided on the inner wall side surface S of the casing 2, and the inner surface (inner wall end surface T) of the lid 4 is substantially continuous with the groove 39.
A groove 40 is provided in the. With these two grooves 39, 40,
A circulation flow path for the stock solution to be treated is formed, and as in the third embodiment, the stock solution to be treated flows as shown by the arrow in FIG. 10, and the amount of the stock solution to be treated circulates in the through hole 24 of the rotary flat film 14. Can be a lot. Four sets of grooves 39 and 40 are provided at equal positions.

12 and 13 show a fifth embodiment of the rotary membrane separator according to the present invention, FIG. 12 is a schematic sectional view thereof, and FIG. 13 is a view taken along the line EE of FIG. . The feature of the fifth embodiment is that the casing 42 is integrated with the main body 42a and the lid portion 42b, and the baffle plate 41 is provided from the inner wall side surface S of the main body 42a to the inner surface (inner wall end surface T) of the lid portion 42b. is there.

That is, the casing 42 is composed of a substantially cylindrical main body 42a and a lid portion 42b closing one end side of the main body 42a, and the opening portion at the other end of the main body 42a has
A cover 44 that rotatably supports the rotating shaft 6 via the shaft sealing member 43 is provided. And this casing 4
On the inner wall side surface S and the inner wall end surface T of the main body 42a, a substantially L-shaped baffle plate 41 is provided integrally with the casing 42, or a separate baffle plate 41 is fixedly provided. Also in the fifth embodiment, the same operational effects as the above-mentioned respective embodiments can be obtained.

FIG. 14 is a vertical cross-sectional view showing a sixth embodiment of the rotary membrane separator according to the present invention. The feature of the sixth embodiment is that the side surface 2c of the casing 2 and the central portion of the lid 4 are perforated. The point is that a pipe 33 for a circulation flow path for circulating the stock solution to be treated is provided in the through hole 24 of the rotary flat film 14 between the provided hole 32. That is, a plurality of outlets 34 are provided on the side surface 2c of the casing 2, a hole 32 is provided in the central portion of the lid 4 that seals the opening of the casing 2, and the outlets 34 and the holes 32 are provided outside the casing 2. It connects by piping 33.

According to the sixth embodiment, a protruding flow or the like protruding from the space between the rotary flat films 14 to the outer peripheral side is returned from the discharge port 34 into the casing 2 through the pipe 33 and the hole 32 of the lid 4,
A circulating flow flowing from the inner wall side surface S of the casing 2 to the through hole 24 portion is generated. At this time, the inner wall side surface S of the casing
The stock solution to be treated is once discharged to the outside of the casing 2 and is reliably returned to the through hole 24 portion, so that the circulating flow flowing in the through hole 24 in the axial direction can be made stronger, and the same as in each of the above embodiments. The effect is obtained.

The present invention is not limited to each of the above embodiments. For example, a baffle plate is provided on the inner wall side surface or the inner wall end surface of the casing, and the inner wall end surface of the casing or the baffle plate is connected to the baffle plate. It is also possible to appropriately combine the embodiments, such as providing a groove on the side surface of the inner wall. Further, in each of the above embodiments, the case where the baffle plate, the groove or the like is necessarily provided on the side surface of the inner wall of the casing has been described, but the baffle plate or the groove may be provided only on the end surface of the inner wall of the casing.

Further, in the construction of the casing and the membrane separating means in each of the above-mentioned embodiments, for example, a plurality of support pipes are fixed to the end of the rotary shaft, and the support pipe has a through hole in the central portion. A structure may be used in which a plurality of rotary flat membranes arranged to face each other are supported and an end plate having a large number of through holes communicating with the through holes of the rotary flat membrane is fixed to the end of the support pipe, or the rotary flat membranes are fixed. The membrane may be supported by a hollow rotary shaft, and an opening for circulating flow may be provided near the outer peripheral side of the hollow flat shaft of the rotary flat membrane.

Further, in each of the above-mentioned embodiments, the structure of the rotary flat film, the number, shape and arrangement position of the baffle plates and grooves, the structure and shape of the casing, etc. are merely examples, and do not depart from the scope of the present invention. It goes without saying that various changes can be made in.

[0037]

As described in detail above, according to the rotary membrane separation apparatus of the present invention, since the baffle plate or the groove is provided on at least one of the inner wall side surface and the inner wall end surface of the casing, the inside of the casing is covered. It is possible to form a circulation flow path for the processing stock solution and increase the circulation flow in the axial direction.
There are effects such as a sufficient effect of reducing concentration polarization.

[Brief description of the drawings]

FIG. 1 is a vertical side view showing a first embodiment of a rotary membrane separation device according to the present invention.

FIG. 2 is a view taken along the line AA of FIG.

FIG. 3 is a graph showing the relationship between the membrane outer peripheral velocity and the permeation flux.

FIG. 4 is a view similar to FIG. 2 showing a modified example thereof in the direction of the arrow.

FIG. 5 is a perspective view showing another modification of the same.

FIG. 6 is a longitudinal sectional view showing a second embodiment of the rotary membrane separation device according to the present invention.

FIG. 7 is a view taken on line BB of FIG. 6;

FIG. 8 is a vertical cross-sectional view showing a third embodiment of the rotary membrane separation device according to the present invention.

9 is a view taken along the line CC of FIG.

FIG. 10 is a longitudinal sectional view showing a fourth embodiment of the rotary membrane separation device according to the present invention.

FIG. 11 is a view taken along the line DD of FIG.

FIG. 12 is a schematic sectional view showing a fifth embodiment of the rotary membrane separator according to the present invention.

13 is a view taken along the line EE of FIG.

FIG. 14 is a schematic vertical sectional view showing a sixth embodiment of the rotary membrane separator according to the present invention.

[Explanation of symbols]

 1 --- Membrane separation device 2 --- Casing 3 --- Membrane separation means 6 --- Rotation shaft 6a・ ・ ・ ・ ・ ・ ・ ・ Channel 9 ・ ・ ・ ・ ・ ・ Baffle plate 14 ・ ・ ・ ・ ・ ・ Rotating flat membrane 16 ・ ・ ・ ・ ・ ・ Post 16a ・ ・ ・ ・ ・..Channel 23 ..... Filtration membrane 24 ..... Through hole 21 .... Nut 27 ..... Baffle plate 27a ..・ ・ ・ Sloping surface 28 ・ ・ ・ ・ ・ ・ Baffle plate 31 ・ ・ ・ ・ ・ ・ Groove 32 ・ ・ ・ ・ ・ ・ Hole 33 ・ ・ ・ ・ ・ ・ Piping 36, 37 ... Baffle plate 39, 40 ... Groove 41 ... Baffle plate 42 ... Casing 42a ... Main body 42b ...・ ・ ・ Lid S ・ ・ ・ ・ ・ ・ ・ Inside wall side T ・..... inner wall end face

Claims (4)

[Claims] 1. A rotary membrane separation device in which a plurality of disk-shaped rotary flat membranes are arranged on a rotary shaft in a casing, wherein a through hole is provided near the rotary shaft of the rotary flat membrane, and an axial direction of the casing is provided. At least one of the inner wall side surface and the inner wall end surface is provided with a flow path forming means for forming a flow path for guiding the stock solution to be treated in the casing to the through hole portion. 2. The rotary membrane separation apparatus according to claim 1, wherein the flow path forming means is a ridge. 3. The rotary membrane separation device according to claim 1, wherein the flow path forming means is a groove. 4. A rotary membrane separation device in which a plurality of disk-shaped rotary flat membranes are arranged on a rotary shaft in a casing, wherein a through hole is provided near the rotary shaft of the rotary flat membrane, and the rotary flat membrane is provided outside the casing. A rotary membrane separation device, characterized in that a communication passage communicating from the outer peripheral wall of the casing to the through hole portion of the rotary flat membrane is provided.