JPH11137975A - Membrane separation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the clogging of a membrane module caused by the vibration of a membrane separation device. SOLUTION: A raw water in a raw water tank 60 is supplied to a membrane separation device main body 64 through a pump 61, a stop valve 70 and a flexible tube 71 and treated by membrane separation. A branch pipe 72 is branched from the upstream side of the stop valve 70 and a pressure control valve 73 is provided on the branch pipe 72. In the membrane separation device formed in this way, the vibration of water feed pressure generated in the pump 61 is remarkably reduced by making a part of the pump discharge water to flow out from the branch pipe 72 and absorbed by the flexible tube 71. Karman's voltex is hardly generated by fully opening the pressure control valve 73 usually.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a membrane separation device such as a microfiltration device, an ultrafiltration device, and a reverse osmosis membrane separation device, and more particularly to a membrane separation device suitable when a spiral type membrane module is used as a membrane module. Related to the device.

[0002]

2. Description of the Related Art As a membrane module used in a membrane separation apparatus, there is a spiral type membrane module in which a separation membrane is wound around a water collecting pipe.

FIG. 5 is a partially exploded perspective view showing the structure of a conventional spiral membrane module.

A plurality of bag-shaped separation membranes 2 are wound around the outer periphery of a water collecting pipe 1 via a mesh spacer 3.

[0005] The water collecting pipe 1 is provided with a slit-shaped opening communicating with the inside and outside of the pipe. The separation membrane 2 has a bag shape,
The central part surrounds the water collection pipe 1. A channel material 4 made of a mesh spacer or the like is inserted inside the bag-shaped separation membrane 2, and the inside of the bag-shaped separation membrane (bag-shaped membrane) 2 is a permeated water channel.

[0006] A top ring 6 and an end ring 7 are provided at both ends of a wound body 5 of the bag-shaped membrane 2, and a brine seal 8 is provided around the outer periphery thereof.

The raw water flows into the raw water flow path between the bag-like membranes 2 from the front end face of the wound body 5, flows in the longitudinal direction of the wound body 5 as it is, and concentrates from the rear end face of the wound body 5. Leaked as. While flowing through the raw water flow path, water permeates the bag-like membrane 2 and enters the inside thereof, flows into the water collecting pipe 1, and is taken out of the module from the rear end side of the water collecting pipe 1.

FIG. 6 is a diagram showing a water flow system of a conventional membrane separation apparatus.
It is supplied to the membrane separation device main body 64 via the pressure adjusting valve 63. The membrane separation device main body 64 has a membrane module inserted in a counter pressure vessel, and the permeated water is supplied through a permeated water extraction line 6.
5 and the concentrated water is taken out from the concentrated water discharge line 66.

[0009]

In the conventional membrane separation apparatus shown in FIG. 6, particularly when a spiral type membrane module is used as a membrane module, when the feed pressure of raw water introduced into the main body of the membrane separation apparatus vibrates finely. It has been found that clogging is likely to occur in the membrane module. This is considered to be because particles adhering to the film surface penetrate into the film surface due to vibration, and the attached matter is compacted.

A first object of the present invention is to prevent clogging of a membrane module due to such vibration.

[0011] The above-mentioned conventional spiral membrane module has the following problems to be solved.

In order to increase the flow rate of the permeated water in the water collecting pipe 1, it is necessary to increase the diameter of the water collecting pipe 1, but in such a case, the diameter of the spiral membrane module also becomes large. The permeated water that has permeated into the bag-shaped membrane 2 flows to the water collecting pipe 1 while spirally flowing through the bag-shaped membrane 2.
The flow resistance in the bag-like membrane 2 is large. Moreover, the flow resistance near the slit portion of the water collecting pipe flowing into the water collecting pipe 1 from the inside of the bag-shaped membrane 2 is large. The flow rate of the raw water flowing through the raw water flow path decreases toward the downstream side. (The flow rate of raw water decreases as much as the raw water is concentrated.)
For this reason, the raw water flow velocity is low in the downstream of the raw water flow path,
Dirt easily adheres.

A second object of the present invention is to solve such a problem and to provide a membrane separation device provided with a spiral type membrane module which does not require a collecting pipe and has low permeated water flow resistance.

[0014]

The membrane separation device of the present invention comprises:
A membrane separation device main body in which a membrane module is installed in a pressure-resistant container, and a pump for supplying a liquid to the membrane separation device main body,
In a membrane separation device having a pump and a liquid supply line connecting the membrane separation device main body, a branch pipe is branched from the liquid supply line, and a pressure regulating valve is provided in the branch tube, and the liquid supply line is provided. Of these, an on-off valve is provided downstream of the branch point of the branch pipe, and at least a part of the liquid supply pipe downstream of the on-off valve is a flexible tube.

By branching the branch pipe from the liquid supply line in this way, the vibration generated by the pump can escape through the branch pipe, and the vibration applied to the water supply of the main body of the membrane separation device is reduced. .

The vibration is absorbed by providing a flexible tube in the liquid supply line.

In the present invention, since the on-off valve is provided on the upstream side of the flexible tube, the vibration accompanying the Karman vortex generated from the on-off valve is absorbed by the flexible tube.

Since the vibration of the liquid supplied from the liquid supply line to the membrane separation device main body or the mechanical vibration transmitted through the liquid supply line is reduced, clogging of the membrane module is prevented. Will be done.

In the present invention, in the membrane module installed in the main body of the membrane separation device, the permeated water flow path material is disposed inside the bag-like membrane, and the raw water flow path material is disposed between the bag-like membranes. A spiral-type membrane module, wherein the bag-like membrane has a substantially rectangular shape having first, second, third, and fourth sides.
The first, second and third sides are sealed, the fourth side is partially open and the remainder is closed, and the first side is orthogonal to the fourth side. A side portion is applied to a shaft to wind a bag-like membrane to form a roll, and the fourth side faces a rear end surface of the roll and a second side facing the fourth side. The raw water flow path between the bag-shaped membranes is sealed with the entire third side, and the fourth side is sealed with the fourth side.
It is preferable that, in the side portion, the portion overlapping the open portion of the bag-like film is a closed portion and the portion overlapping the closed portion of the bag-like film is an open portion.

In such a spiral type membrane module, raw water flows into the raw water flow path from the front end face of the wound body. The raw water flows through the raw water flow path in a direction substantially parallel to the axis of the wound body, and then flows out as concentrated water from the raw water flow path opening at the rear end face of the wound body.

The water that has passed through the bag-like membrane flows in the bag-like membrane in a direction substantially parallel to the axis of the wound body, and flows out from the bag-shaped membrane opening at the rear end face of the wound body.

As described above, since the permeated water flows in the bag-shaped membrane in a direction parallel to the axis of the wound body, the water collecting pipe used in the conventional spiral membrane module becomes unnecessary. Then, there is no flow resistance when flowing into the water collecting pipe from inside the bag-shaped membrane, and the flow resistance of permeated water is reduced.

Since the water collecting pipe is eliminated, the length of the bag-shaped membrane in the winding direction can be increased accordingly.
The membrane area can be expanded. And even if the length in the winding direction of the bag-like membrane is increased, the flow resistance of the permeated water does not increase,
The amount of permeated water can be increased.

In this membrane module, since the raw water flow path is opened only at a part of the rear end face of the wound body, the flow rate of the raw water (concentrated water) downstream of the raw water flow path is increased as compared with the conventional case. It is possible to prevent the adhesion of dirt in the downstream area of the raw water flow path.

In this membrane module, the open portion of the bag-shaped membrane is disposed on the outer peripheral side or inner peripheral side of the rear end face of the wound body, and the raw water flow path is formed on the inner peripheral side or outer peripheral side of the rear end face of the wound body. An annular member for separating the permeated water flowing out from the open portion of the bag-shaped membrane and the concentrated water flowing out from the open portion of the raw water flow path is connected to the rear end surface of the wound body. Is preferred.
The annular member defines an outflow side of raw water and an outflow side of concentrated water.

[0026]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 7 is a system diagram of the membrane separation apparatus according to the embodiment.

In this membrane separation device, the feed line 62
An opening / closing valve 70 is provided at the downstream side of the opening / closing valve 70, and a flexible tube 71 made of synthetic resin is provided downstream of the opening / closing valve 70. A branch pipe 72 branches from the liquid supply pipe 62 upstream of the on-off valve 70, and a pressure adjusting valve 73 is provided in the branch pipe 72. This branch pipe 72 is a raw water tank 6
It is routed to return the raw water to zero.

Other structures are the same as those in FIG. 6, and the same reference numerals indicate the same parts.

In the membrane separation apparatus thus configured, the vibration of the feed water pressure generated by the pump 61 is significantly reduced by a part of the water discharged from the pump from the branch pipe 72 and absorbed by the flexible tube 71. Is done. In addition, by setting the pressure regulating valve 73 to the fully opened state in a normal case, almost no Karman vortex is generated,
Even if a Karman vortex is generated and a slight vibration is generated, the vibration is absorbed by the flexible tube 71. The water supply pressure to the membrane separation device main body 64 is adjusted by adjusting the opening of the pressure adjusting valve 73, so that the opening of the on-off valve 70 need not be adjusted.

The vibration transmitted through the pipe wall from the pump 61 and the on-off valve 70 is absorbed by the flexible tube 71,
It hardly propagates to the membrane separation device main body 64.

As described above, since the vibration transmitted to the main body of the membrane separation device is extremely small, clogging of the membrane module is prevented, and the membrane separation device can be operated stably.

Next, a spiral membrane module suitable for use in the present invention will be described.

FIG. 1A is a perspective view of one bag-like membrane used in the spiral membrane module and a shaft around which the bag-like membrane is wound. FIGS. 1B and 1C are cross-sectional views taken along lines BB and CC of FIG. 1A, respectively. FIG. 2 is a sectional view showing a method of winding a bag-like membrane around a shaft, FIG. 3 is a perspective view showing an engagement relationship between a wound body and a socket, and FIG. 4 is a side view of a spiral membrane module.

The bag-like film 10 has a square or rectangular shape, and has a first side 11, a second side 12, a third side 13, and a fourth side 14. I have. This bag-shaped membrane 10 is formed by folding one long separation membrane film into two at the second side portion 12 and separating the separation membrane films folded at the first side portion 11 and the third side portion 13 from each other. The fourth side portion 14 is formed in a bag shape with an open portion without being bonded by an adhesive or the like.

From the middle of the fourth side 14 to the third side 13
The separation membrane films of the bag-like membrane 10 are not adhered to each other, and the opening portion 30 for permeated water outflow is formed. Further, from the middle of the fourth side portion 14 to the first side portion 11, the separation membrane films of the bag-like membrane 10 are adhered to each other, forming a closing portion 31 for preventing outflow of permeated water. I have.

A channel material (for example, a mesh spacer) 15 is inserted and arranged in the bag-like membrane 10. In addition, the bag-shaped film 10 is not limited to a single long film folded in two at the second side 12,
The two separation membrane films are overlapped, and the first side portion 11,
The second side part 12, the third side part 13, and a part of the fourth side part 14 may be bonded.

On one surface of the bag-like film 10, an adhesive 1
6 is adhered and adhesives 17 and 18 are adhered to the other surface, and the bag-like film 10 is wound around the shaft 20. The adhesive 16 is applied along the first side 16, and the adhesive 17 is applied along the third side 13. The adhesive 18 is applied along the opening 30 for outflow of permeated water from the intermediate portion in the longitudinal direction of the fourth side portion 14 to the third side portion 13.

By winding a plurality of bag-shaped membranes 10 around the shaft 20, the overlapping bag-shaped membranes 10 are joined to each other at the adhesives 16, 17, and 18 in a water-tight manner. Thus, a raw water flow path through which raw water (and concentrated water) flows is formed between the bag-like membranes 10, 10,....
As the adhesive 18 cures, an open portion for flowing out the raw water (concentrated water) is formed on the rear end surface of the wound body on the inner peripheral side, and a closing portion for preventing raw water outflow is formed on the outer peripheral side. You.

Fins 19 extend from the boundary between the open portion 30 for permeate outflow and the closed portion 31 for permeate outflow prevention in the fourth side portion 14 toward the rear of the wound body. I have. The fins 19 are made of, for example, a synthetic resin film or sheet, and are preferably bonded to the bag-like film 10 by adhesion or the like.

.. Are wound around the shaft 20 via the mesh spacer 29 as shown in FIG. 2 to form a wound body 24 as shown in FIG. The fin 19 extends from the rear end face of the wound body 24. By providing the fins 19 at the same location on the fourth side portion 14 of each bag-like membrane 10, the fins 19 are located on the same radius from the axis of the wound body 24, and the fins 19 overlap. The fin 19 forms a ring-shaped protrusion. The rear end of the cylindrical socket 25 is inserted into the ring-shaped protrusion, and the socket 25 and the fin 19 are joined with an adhesive or the like. The socket 25
May be externally fitted to the fins 19. Further, a cutting groove may be formed on the rear end face of the wound body 24 along the fins 19 with a lathe, and the end of the socket 25 may be embedded in the groove.

By joining the socket 25 and the fin 19 in this manner, a permeated water outflow area on the outer peripheral side of the rear end face of the wound body 24 and a concentrated water outflow area on the inner peripheral side of the socket 25 are defined. .

When the bag-like film 10 is wound around the shaft 20, as shown in FIG.
A mesh spacer 29 is interposed between them. By interposing these mesh spacers 29,
A raw water flow path is configured.

As shown in FIG. 4, a top ring 26 and an end ring 27 are provided at the leading edge and the trailing edge of the wound body 24, respectively.
Is formed by a synthetic resin mold or the like, and the top ring 26 is formed.
A brine seal 28 is provided around the outer periphery of.

In the spiral type membrane module configured as described above, as shown in FIG. 4, raw water flows into the raw water flow path between the bag-shaped membranes 10, 10,. I do. This raw water flows through the raw water flow path in a direction substantially parallel to the axis of the wound body 24, and is taken out from the end face inside the socket 25 at the rear end of the wound body 24. Then, while the raw water flows through the raw water flow path, the water permeates into the bag-like membrane 10, and the permeated water flows through the socket 25 on the rear end face of the wound body 24.
Flows out from the outer periphery of the.

In this spiral membrane module, the permeated water flows in the bag-like membrane 10 in a direction parallel to the axis of the wound body 24 and is taken out from the rear end face. The used collecting pipe is unnecessary. For this reason, the flow resistance when flowing from the bag-like membrane into the water collecting pipe is eliminated, and the permeated water flow resistance is significantly reduced.

The water collecting pipe is omitted, and the length of the bag-like membrane 10 in the winding direction can be increased accordingly.
It is possible to increase the film area. Even if the length of the bag-like membrane in the winding direction is increased, the permeated water flow resistance does not increase,
The amount of permeated water can be increased.

In this embodiment, the outlet portion of the raw water flow passage is provided only inside the socket 25, and the outlet (the most downstream portion) of the raw water flow passage is narrowed. Also on the downstream side, the flow rate of the raw water (concentrated water) becomes sufficiently large, and it is possible to prevent the adhesion of dirt in the downstream area of the raw water flow path. The area inside and outside the socket 25 (the length of the adhesive 18 in the side portion 14 direction) is preferably determined according to the water recovery rate of the spiral-wound membrane module.

In this embodiment, the socket 25 is connected to the winding body 24 using the fins 19, and the connection strength between the socket 25 and the winding body 24 is high. Then, the inflow side of the raw water and the outflow side of the concentrated water are partitioned in a watertight manner by the socket 25.

In the above embodiment, the permeated water outflow portion is arranged on the outer peripheral side of the socket 25,
Although the concentrated water outflow portion is disposed inside the inside, the inside of the socket 25 may be configured as the permeated water outflow portion, and the outer peripheral side of the socket 25 may be configured as the concentrated water outflow portion.

[0051]

EXAMPLE 1 A membrane module having the structure shown in FIGS.
² ) was incorporated in the membrane separation device main body 64 of FIG.

Comparative Example 1 The same membrane module as in Example 1 was used,
4 incorporated.

Using tap water as raw water, water was passed in Example 1 and Comparative Example 1 under the following conditions,
4. Measure the pressure difference between the raw water inflow pressure and the permeate outlet pressure,
The result is shown in FIG.

Permeated water flux 100 m ³ / m ² / Day Recovery rate 50% Backwash frequency Once every 7.5 min (1 minute per time) The branch outflow to the branch pipe in the pump discharge amount in Example 1 The amount was 10%, and a pressure-resistant rubber tube having a length of 2 m and an inner diameter (diameter) of 40 mm was used as a flexible tube.

As is clear from FIG. 8, according to the first embodiment, it is clear that the operation can be performed for a long period of time with a low differential pressure and a high permeate flux.

[0056]

As described above, in the membrane separation device of the present invention, the vibration generated by the pump and the valve is hardly transmitted to the main body of the membrane separation device. High permeate water flux operation can be performed with pressure.

[Brief description of the drawings]

1A is a perspective view of a bag-shaped membrane of a spiral-type membrane module suitable for use in the present invention, FIG. 1B is a cross-sectional view taken along the line BB of FIG. c) is a sectional view taken along the line CC in FIG.

FIG. 2 is a cross-sectional view showing a method of winding a bag-like membrane of the spiral membrane module of FIG.

FIG. 3 is a perspective view showing an engagement relationship between a wound body and a socket.

FIG. 4 is a side view of the spiral membrane module of FIG. 1;

FIG. 5 is a partially exploded perspective view showing the structure of a conventional spiral membrane module.

FIG. 6 is a system diagram of a conventional membrane separation device.

FIG. 7 is a system diagram of the membrane separation device of the present invention.

FIG. 8 is a graph showing the results of Examples and Comparative Examples.

[Explanation of symbols]

 Reference Signs List 10 bag-like membrane 11 first side 12 second side 13 third side 14 fourth side 15 flow path material 16, 17, 18 adhesive 19 fin 20 shaft 24 wound body 25 socket 29 Mesh spacer 30 Open part for permeated water outflow 31 Closed part for permeated water outflow prevention 60 Raw water tank 61 Raw water pump 62 Liquid supply line 63, 73 Pressure regulating valve 64 Membrane separation device main body 70 Open / close valve 71 Flexible tube 72 Branch pipe

Claims (3)

[Claims] 1. A membrane separation device main body having a membrane module installed in a pressure-resistant container, a pump for supplying a liquid to the membrane separation device main body, and a liquid supply line connecting the pump and the membrane separation device main body. Wherein the branch pipe is branched from the liquid supply pipe, a pressure regulating valve is provided on the branch pipe, and an on-off valve is provided on the liquid supply pipe downstream of a branch point of the branch pipe. And a flexible tube at least a part of the liquid supply pipe downstream of the on-off valve. 2. The spiral membrane module according to claim 1, wherein the permeated water flow path material is disposed inside the bag-shaped membrane, and the raw water flow path material is disposed between the bag-shaped membranes. Wherein the bag-like membrane is substantially rectangular with first, second, third and fourth sides, wherein the first, second and third sides are sealed,
A part of the fourth side is an open part and the remaining part is a closed part, and a first side perpendicular to the fourth side is applied to a shaft to wind a bag-like membrane. A body having a fourth side facing the rear end face of the wound body, a second side facing the fourth side facing the front end face of the wound body, In the raw water flow path between the membranes, the entire third side portion is sealed, and in the fourth side portion, a portion overlapping with the open portion of the bag-shaped membrane is a closed portion, The membrane separation device is a spiral type membrane module in which a portion overlapping the closed portion of the bag-shaped membrane is an open portion. 3. The spiral wound membrane module according to claim 2, wherein the open portion of the bag-shaped membrane of the spiral membrane module is arranged on an outer peripheral side or an inner peripheral side of a rear end surface of the wound body, and the raw water flow path is formed by the wound body. An annular member is disposed on the inner peripheral side or the outer peripheral side of the rear end face, for separating the permeated water flowing out from the open portion of the bag-like membrane and the concentrated water flowing out from the open portion of the raw water flow path. A membrane separation device connected to a rear end surface of the wound body.