JPH0839061A - Immersion type membrane separator - Google Patents

Abstract

PURPOSE:To enhance the effect of chemical washing by distributing a chemical soln. over the entire surface of a membrane. CONSTITUTION:Four water passing ports are provided to the respective membrane elements 2 of an immersion type membrane separator and the upper and lower right water passing ports among them are connected to the first and second take-out pipes 26a, 26b on a suction pipe side through first and third water passages 21, 23 and the upper and lower left water passing ports among them are connected to first and second water or chemical soln. supply pipes 32a, 32b through second and fourth water passages 22, 24 and opening and closing valves 27a, 27b, 27c, 27e, 27f are provided to the take-out pipes and the supply pipes to select the water passing ports. The flow direction of water or a chemical soln. at the time of the introduction of water or the chemical soln. into the transmission chambers of the respective membrane elements can be changed over by valve changeover operation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a reverse osmosis membrane, an ultrafiltration membrane, a microfiltration membrane, a polymer membrane, an inorganic (alumina ceramic, etc.) membrane, and a permeation chamber in which water permeated through the membrane enters. The present invention relates to an immersion type membrane separation device that performs a membrane separation treatment by immersing a membrane element having the above in a plurality of liquids.

[0002]

2. Description of the Related Art Immersion type membrane separators are capable of obtaining permeated water by performing membrane separation with low energy due to the water head difference based on the water depth in the immersion tank in which the membrane element is immersed and the suction force of the suction pump. In such an immersion type membrane separation device, the permeation flux is maintained by peeling the cake and gel layer on the membrane surface by intermittent stoppage, bubbling, air lift upward flow, etc.
Adhesion becomes irreversible during long-term operation, requiring chemical cleaning. Therefore, the applicant of the present application filed Japanese Patent Application No. 5-291516.
The connection port is provided at the opposite corner of the membrane element, the extraction pipe of the suction pump is connected to one of the connection ports, and the supply pipe for supplying water or the chemical liquid is connected to the other connection port. We proposed an immersion type membrane separation device configured to be washed.

[0003]

However, in the above-mentioned immersion type membrane separation device, it is difficult to evenly distribute the chemical liquid over the entire surface of the membrane, and the connection port serving as the chemical liquid inlet and the connection port serving as the outlet are straight lines. Only the area connected with was washed with chemicals, and the unwashed area was wide. Therefore, there is a problem that the effect of chemical cleaning gradually decreases and the membrane performance cannot be maintained. Therefore, an object of the present invention is to provide a submerged membrane separation device in which a chemical solution is distributed over the entire surface of the membrane to improve the effect of chemical cleaning.

[0004]

DISCLOSURE OF THE INVENTION The present invention has been proposed in order to achieve the above object. According to a first aspect of the present invention, a plurality of membrane elements having permeation chambers for receiving permeated water are arranged in a liquid. In a submerged membrane separation device which is immersed in the inside to perform a membrane separation device, each membrane element is provided with three or more water passage ports, and at least one of these water passage ports is connected to a suction pipe on the suction pump side.
A water or chemical solution supply pipe is connected to the remaining water passage port, and a valve is provided on the pipe to select the water passage port that communicates with the pipe.By switching the valve, water or chemical liquid is introduced into the permeation chamber of each membrane element. The flow direction when switching is made switchable. According to the second aspect of the present invention, membranes are arranged on both sides of the spacer, water collecting pipes are provided at opposite edges, and a permeation flow path of the spacer is connected to the water collecting pipe to form a membrane element. In an immersion-type membrane separation device that performs membrane separation by arranging multiple elements side by side in the liquid, connect one water collection pipe of each membrane element to the extraction pipe on the water absorption pump side, and supply the other water collection pipe to water or chemical liquid. It is connected to a pipe.

[0005]

In the submerged membrane separation apparatus according to the first aspect, when the valve of the feed pipe and the valve of the take-out pipe are appropriately switched, the position of introduction into the permeation chamber of the membrane element and the position of discharge are changed, As a result, the flow region of the cleaning liquid in the permeation chamber is switched. Therefore, the cleaning liquid can be flowed over the entire surface of the membrane by switching the flow region of the cleaning liquid. Further, according to the second aspect, since one of the water collecting pipes linearly communicates with one side of the permeation passage between the membranes, when the cleaning liquid is supplied from the one of the water collecting pipes, the permeation between the membranes is performed. From the beginning, the cleaning liquid spreads in the flow channel with a spread, and since the other water collection pipe is in linear communication with the other side of the permeation flow channel,
The cleaning liquid in the permeation channel is discharged from the other water collecting pipe while spreading as it is. Therefore, the entire surface of the film can be cleaned.

[0006]

Embodiments of the present invention will be described below with reference to the drawings. The single membrane element 2 that constitutes the membrane unit 1 has flat and square flat membranes 4 and 4 on both sides of a flat, square, net-shaped flow path spacer 3 made of tricot knitted fabric.
The four peripheral edges are sealed by heat, adhesion, high-frequency welding or the like to be integrally formed, and a permeation chamber 6 surrounded by the seal 5 is formed between two flat membranes. The membrane element 2 may be one in which the spacers of the porous member are directly formed on both the front and back surfaces. A water passage 7 is provided at each corner in the permeation chamber 6 surrounded by the seal 5 in each membrane element 2. That is, in this embodiment, a total of four water passages 7a, 7b, 7c, 7d are provided at the corners of the membrane element 2.

Numeral 8 is an elastic gasket which is arranged at each corner having the water passage port 7 of the membrane element 2 and maintains a predetermined water passage distance between two adjacent membrane elements 2, and at the corner of the membrane element 2. It is a triangle or a quadrangle having two corresponding right-angled sides, and has an opening 9 of the same size that communicates with the water passage 7.

Numerals 10 and 11 are gaskets and a water passage interval 12
It is an end plate that sandwiches a row of a plurality of membrane elements 2 that are arranged side by side while maintaining the same, and has a size of the membrane elements 2.
Is the same size as. A through hole 13 that communicates with the water passage 7 of the membrane element 2 is formed in each of the end plates 10 and 11.

The through hole 13 of the end plate has a large diameter portion 14 having the same size as the water passage 7 of the membrane element 2 and the opening 9 of the gasket, and the remaining portion has a small diameter portion 16 through which the tightening bolt 15 passes. It has become. Then, a connection port 17 opened to the outer surface is provided at the back of the large diameter portion 14. Therefore, in the present embodiment, the connection port 1 communicating with each water passage port 7a of the membrane element 2 is connected.
7a, a connection port 17b communicating with each water communication port 7b, a connection port 17c communicating with each water communication port 7c, and a connection port 17d communicating with each water communication port 7d are independently opened.

In order to assemble the membrane unit 1, a predetermined number of membrane elements 2 are lined up in a row with the gasket 8 in between (the water passage 7 of the membrane element 2 and the opening 9 of the gasket are communicated) and are communicated with each other. All membrane elements 2
The bolts 15 are passed through the water passage 7 and the openings 9 of all the gaskets 8 in series, the through holes 13 are fitted to the respective ends of the bolts 15, and the membrane element 2 is sandwiched between the end plates 10 and 11, and the bolts 15 A nut 18 screwed to each end is provided with end plates 10 and 11
Then, the membrane element 2 and the gasket 8 are pressed together to be integrated.

The through hole 13 at each end of the bolt 15 is provided.
An O-ring 19 is fitted and sealed in a portion located inside the small diameter portion 16. Thereby, the through holes 13 of the end plates 10 and 11
The large diameter portion 14, the opening 8 of the gasket 8 and the water passage 7 of the membrane element 2 are connected in series, and the first and second water channels 21 and 22 for communicating the permeation chamber 6 of each membrane element 2 In addition, third and fourth water channels 23 and 24 are formed in parallel in the lower portion.

When the membrane unit 1 having the above-mentioned structure is immersed in the liquid in the dipping tank 25, the first outlet pipe 26a is connected to the connection port 17a of the end plate 10 of the first water channel 21 which is located above. 2nd to the connection port 17c in the end plate 10 of the third water channel 23
The extraction pipe 26b is connected, and the downstream side of the first extraction pipe 26a having the first opening / closing valve 27a in the middle and the downstream side of the second extraction pipe 26b having the second opening / closing valve 27b in the middle are joined to form the main extraction pipe. A suction pump 28 is provided on the way as 26c. The main extraction pipe 26c is branched into two downstream of the suction pump 28,
One of the branch pipes 29a having the opening / closing valve 27c in the middle is erected, and the water surface is the same as that of the immersion tank 25 or is opened from above to the storage tank 30 of the permeated water higher than it, and the fourth opening / closing valve 27d is inserted in the middle. The other one of the branch pipes 29 b that they have extends straight and opens into the drainage tank 31.

Further, the first supply pipe 32a is connected to the connection port 17b in the end plate 11 of the second water channel 22 which is soaked up, and the connection port 17d in the end plate 11 of the fourth water channel 24 is down. The second supply pipe 32b is connected to the upstream side of the first supply pipe 32a having the fifth opening / closing valve 27e in the middle and the upstream side of the second supply pipe 32b having the sixth opening / closing valve 27f in the middle. The main supply pipe 32c is used, and the upstream end of the main supply pipe 32c is projected into the liquid in the storage tank 30 from above and connected to the strainer. The connection ports 17 of the end plates 10 and 11 to which the take-out pipe 26 or the supply pipe 32 is not connected are closed with plugs.

Then, a chemical injection pipe 35 for injecting the chemical liquid in the chemical liquid tank 33 with a chemical liquid pump 34 is connected in the middle of the main supply pipe 32c. In addition, the dipping tank 25 has a raw water supply pipe 36 at the top.
And a sludge discharge pipe 37 is provided at the bottom.

To collect the permeated water, the first, second and third on-off valves 27a, 27b and 27c are opened and the fourth, fifth and sixth valves are opened.
The on-off valves 27d, 27e, 27f are closed, and the suction pump 2
Drive 8 As a result, of the liquid in the immersion tank 25,
The permeated water that has permeated the membrane due to the suction of the suction pump 28 and the head difference from the permeation chamber 6 of each membrane element 2 into the first and third water channels 21,
23, and enters the storage tank 30 through the first and second take-out pipes 26a and 26b, the main take-out pipe 26c and the branch pipe 29a.

When the cake of the permeate is collected on the outer surface of the membrane 4 to some extent, the third opening / closing valve 27c is closed, the fourth opening / closing valve 27d is opened, and the first, second, fifth and sixth parts are opened.
The on-off valves 27a, 27b, 27e, 27f are appropriately selected to be opened and closed, and the suction pump 28 and the chemical liquid pump 34 are operated to switch the flow directions of water and the chemical liquid flowing through the permeation chamber 6 of each membrane element 2. To wash.

For example, the first on-off valve 27a and the sixth on-off valve 2
When 7f is closed and the second opening / closing valve 27b and the fifth opening / closing valve 27e are opened (first step), the membrane unit 1 is washed.
The permeated water filling the permeation chamber 6 is drawn by the suction pump 28, flows through the third water passage 23 and the branch pipe 29b from the second extraction pipe 26b into the drainage tank 31, and at the same time the storage tank 30
The permeated water inside is the head difference from the immersion tank 25, and the suction pump 2
The main supply pipe 32c of the replacement water and the first supply pipe 32a by suction of 8
It flows through the inside toward the second water channel 22 of the membrane unit 1 and merges with the chemical liquid injected through the chemical injection pipe 35 to become a cleaning liquid having a predetermined concentration, and the second water channel 2 without applying excessive pressure to the membrane 4.
2 enters the permeation chamber 6 through the water passage 7b of each membrane element 2.

In this way, after the cleaning liquid is replaced with the permeated water in the permeation chamber 6, the suction pump 28 and the chemical liquid pump 3 are briefly held.
When the operation of No. 4 is continued, in the permeation chamber 6 of each membrane element 2, the cleaning liquid flowing from the upper water passage 7b is sucked and discharged from the diagonally lower water passage 7c.
Mainly within the range indicated by the alternate long and short dash line in FIG. In this case, the cleaning effect on the inner surface side of the film 4 is remarkable.

Then, the suction pump 28 and the chemical liquid pump 34
Operation of the fourth on-off valve 2 is stopped in addition to the third on-off valve 27c.
When 7d is also closed and the cleaning liquid is sent from the second water channel 22 to the permeation chamber 6 of each membrane element 2 due to the water head difference between the storage tank 30 and the immersion tank 25, the cleaning liquid in the permeation chamber 6 permeates from the inner surface to the outer surface of the membrane 4. As a result, the cake adhering to the outer surface can be peeled off. In this case, the cleaning liquid permeates in a wider range than the range shown by the one-dot chain line in FIG. Since the cleaning liquid permeates the membrane in the direction opposite to the permeated water, the cake is easily peeled off from the outer surface of the membrane. The removed cake is discharged from the dipping tank 25 by opening the valve of the mud discharge pipe 37.

In the next second step after the completion of the first step, the first on-off valve 27a is opened and the second on-off valve 27b is closed, and the fifth on-off valve 27e is closed to the sixth on-off valve 27f.
Open and wash again in this state by the same operation as above. In this way, in the permeation chamber 6 of each element, the cleaning liquid flowing in from the lower water passage 7d is sucked from the diagonally upper water passage 7a and discharged from the first water passage 21. (B) The area shown by the alternate long and short dash line is strongly washed by the water flow of the washing liquid.

Therefore, if the above first step cleaning and the second step cleaning are performed, it becomes possible to perform strong cleaning over almost the entire surface of the film, and prevent deterioration of the film performance due to residual cleaning. can do.

In the above-described embodiment, in the first step, the cleaning liquid is flowed from the upper left to the lower right of the permeation chamber 6 for cleaning (see FIG. 5).
(A)) In the subsequent second step, the cleaning liquid is flowed from the lower left to the upper right so as to intersect with the flow of the first step to strongly clean almost the entire area of the membrane. The present invention is not limited to this, and various cleaning modes can be adopted by appropriately selecting and opening / closing the open / close valve.

For example, in the first step, the first opening / closing valve 27
a, the fifth opening / closing valve 27e, and the sixth opening / closing valve 27f are opened to the second
When the on-off valve 27b is closed and washed, as shown in FIG. 6 (A), in the permeation chamber 6 of each membrane element 2, the washing liquid flowing from the water passages 7b and 7d opened on one side is located above the other side. The water is sucked from the water passage 7a and discharged from the first water passage 21, and the range indicated by the alternate long and short dash line in the figure is mainly washed intensively. Then, in the next second step, the second opening / closing valve 2
7b, the 5th on-off valve 27e, and the 6th on-off valve 27f are opened, and the 1st on-off valve 27a is closed and it wash | cleans. When the cleaning is performed in this manner, as shown in FIG. 6B, the cleaning liquid flowing in from the water passages 7b and 7d opened on one side in the permeation chamber 6 is sucked from the water passage 7c located below the other side. 3rd waterway 2
3 is discharged, and the range indicated by the alternate long and short dash line in FIG. Therefore, by switching the cleaning between the first step and the second step, almost the entire surface of the film can be strongly cleaned.

The above-mentioned cleaning of the first step and the second step may be carried out continuously. In the first cleaning, only the first step is carried out, and after a certain period of operation, the second cleaning is carried out as the second cleaning. You may make it wash.

Further, in the above-mentioned embodiment, the membrane element 2
Is provided with four water passages 7a, 7b, 7c, 7d, and the connection pipes 17a, 17c of the two water passages 7a, 7c are connected to the extraction pipes 26a, 26b on the suction pump 28 side and the remaining two water passages 7b, 7d. Supply pipes 32a, 3 to the connection ports 17b, 17d of
Open / close valves 27a, 27b, 2 provided on each pipe by connecting 2b
The connection port 17 communicating with each other by switching between 7e and 27f, that is, the water passage port is selectable so that the flow direction of the cleaning liquid introduced into the permeation chamber 6 is switched, but the number of the water passage ports 7 in the present invention is three or more. The valve mechanism for switching the flow of the cleaning liquid in the permeation chamber 6 is not limited to the above embodiment, and the design can be changed as appropriate.

In the first embodiment, the cleaning liquid is introduced from one of the water passages 7 located diagonally to each other, and is collected and washed by suction from the other water passage 7 on the side of the discharge pipe. In the embodiment, the cleaning liquid is introduced from the two water passages 7 and is collected and washed from one water passage 7 located diagonally to these, but the water passages 7 diagonally located to each other are sequentially introduced and collected. You may do it.

Further, as shown in FIG. 7, in the membrane element 2 ', flat membranes 4 and 4 of the same size are superposed on both surfaces of a flat and square spacer 38, and the left and right opposite edges are left open. , The other edge, that is, the upper edge and the lower edge in this embodiment are sealed by heat, adhesion, high-frequency welding, or the like to be integrally formed, and the permeation channel (permeation chamber) is formed between the two flat membranes 4 and 4. ) 39 is formed, and water collecting pipes 40a, 40b are provided at the opposite edges, that is, the left and right edges in this embodiment, and the permeation flow path 39 is communicated with the water collecting pipes 40a, 40b. If a plurality of membrane elements 2 having such a configuration are arranged and immersed as the membrane unit 1 in the liquid in the dipping tank 25, one water collecting pipe 40a
To the main supply pipe 32c and the other water collecting pipe 40b to the main take-out pipe 26c. In addition, each water collection pipe 40a, 40
Although b may be directly connected to the supply pipe or the take-out pipe, a fifth water channel communicating with one of the water collecting pipes 40a group is provided, and a sixth water channel communicating with the other water collecting pipe 40b group is also provided. May be connected to the supply pipe 32 and the sixth water channel may be connected to the extraction pipe 26.

To collect permeated water, the on-off valve between the membrane unit 1 and the suction pump 28, the on-off valve in the middle of the branch pipe to the storage tank 30 are opened, and the on-off valve in the middle of the main supply pipe 32c is closed. Then, the suction pump 28 is operated. As a result, the immersion tank 2
Of the liquid in 5, the permeated water that has permeated the membrane due to the suction of the suction pump 28 and the head difference collects from the permeation flow channel 39 of each membrane element 2 to the other water collection pipe 40b, and passes through the main extraction pipe 26c and the branch pipe. Enter the storage tank 30.

After the permeated water sampling step is performed and the cake has adhered to the outer surface of the membrane to some extent, the on / off valve of the branch pipe to the storage tank 30 is closed, the on / off valve of the main supply pipe 32c is opened, and the suction pump 28 and the chemical liquid pump are opened. 34 is operated, whereby a cleaning liquid such as water or a chemical liquid is introduced into the permeation flow path of each membrane element 2 from one water collecting pipe 40a, and this cleaning liquid is collected and cleaned from the other water collecting pipe 40b.

When the membrane element 2 in this embodiment is washed in this way, one side of the permeation chamber 6 is in communication with one of the water collection pipes 40a and the other side is in communication with the other water collection pipe 40b. The cleaning liquid introduced from the water collection pipe 40a into the permeation flow channel 39 uniformly flows over the entire area of the membrane surface and is collected in the other water collection tube 40b, whereby the entire area of the membrane surface can be reliably cleaned.

In each of the above-described embodiments, the chemical liquid tank 33
Although the permeated water of the storage tank 30 was used to replace the cleaning liquid having a predetermined concentration with the cleaning liquid having a predetermined concentration or to replace the cleaning liquid in the permeation chamber 6, a fresh water tank is provided above the immersion tank 25 in addition to the storage tank 30.
The supply pipe of the replacement water may be rushed into the fresh water of the fresh water tank from above to dilute or replace the chemical liquid with the fresh water.

[0032]

As described above, according to the present invention, the cleaning liquid can be uniformly distributed and cleaned over the entire area of the membrane surface without providing any special means in the permeate side flow passage of the membrane element. . Therefore, the effect of chemical cleaning can be expected every time, and the membrane performance can be maintained for a long time.

[Brief description of drawings]

FIG. 1 is a flow sheet of a first embodiment of the present invention.

FIG. 2 is a perspective view in which a part of a membrane element is peeled off.

FIG. 3 is a front view of a gasket overlaid on a membrane element.

FIG. 4 is an enlarged sectional view of a part of the assembled state of the membrane unit.

FIG. 5 is a front view of a membrane showing a cleaning range, (A) shows a main cleaning range in which a cleaning liquid is passed from an upper left water passage to a lower right water passage, and (B) is a lower left water passage. Shows the main cleaning range with the water passing through the upper right through to the water inlet.

FIG. 6 is a front view of a membrane showing a cleaning range, (A) shows a main cleaning range in which a cleaning liquid is passed from both left water passages to an upper right water passage, and (B) is a left both passages. The main cleaning range is shown from the water inlet to the lower right water inlet.

FIG. 7 is a front view of a membrane element provided with water collecting pipes on the left and right edges of the membrane.

8 is an enlarged sectional view of a water collecting pipe portion of the membrane element shown in FIG.

[Explanation of symbols]

 1 Membrane Unit 2 Membrane Element 3 Channel Spacer 4 Membrane 6 Permeate Chamber 7 Water Port 10, 11 End Plate 17 Connection Port 21 First Channel 22 Second Channel 23 Third Channel 24 Fourth Channel 25 Immersion Tank 26 Ejection Tube 27 Opening / Closing Valve 28 Suction pump 29 Branch pipe 30 Storage tank 31 Drainage tank 32 Supply pipe 33 Chemical liquid tank 34 Chemical liquid pump 35 Chemical liquid pipe 38 Spacer 39 Permeable flow passage 40 Water collection pipe

Claims (2)

[Claims] 1. A submerged membrane separation apparatus in which a plurality of membrane elements each having a permeation chamber for receiving permeated water are arranged and immersed in a liquid to perform a membrane separation apparatus. Each membrane element is provided with three or more water passage ports. , A suction pump side extraction pipe is connected to one or more of these water passages, and a water or chemical solution supply pipe is connected to the remaining water passages, and a valve is provided in the pipes so that the water passages communicating with each other can be selected. An immersion type membrane separation device characterized in that the flow direction when introducing water or a chemical solution into the permeation chamber of each membrane element can be switched by a switching operation. 2. Membranes are arranged on both sides of the spacer, water collecting pipes are provided at opposite edges, and a permeation channel of the spacer is connected to the water collecting pipe to form a membrane element. In a submerged membrane separation device that performs membrane separation by immersing in one of the membrane elements, one of the water collection pipes of each membrane element should be connected to the extraction pipe on the water absorption pump side, and the other water collection pipe should be connected to the water or chemical supply pipe. Characteristic immersion type membrane separation device.