JPH1076144A - Membrane separator by hollow tubular membranes - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a membrane separator by hollow tubular membranes in which an air lift circulating flow is generated while the bundle of hollow tubular membranes is filled into the whole inside of a module and which is effective and is of air lift circulating type having large membrane filling area. SOLUTION: This separator comprises a module outer cylinder 10 concentrically having a lower cylindrical part 11 of small diameter and a gas-liquid separation cylindrical part 12 of large diameter at the lower half part and the upper half part thereof and equipped with an annular water collecting seat 13 positioned above the lower cylindrical part and installed inside the gas-liquid separation cylindrical part, and a membrane element 20 having a potting part 21 fitted in the annular water collecting seat 13 and fixed, a partition 22 fixed to the potting part at the upper end thereof and hung down into the lower part of the inside of the lower cylindrical part and dividing the inside of the lower cylindrical part into two flow passages (a), (b), and a lot of external pressure type hollow tubular membranes 23 fixed to the potting part at the upper end thereof and opened to the upper surface of the potting part at the hollow upper end thereof and hung down into the two flow passages separated by the partition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention uses an external pressure type membrane element having a large number of hollow tubular membranes having a hollow portion such as a hollow fiber membrane or a tubular type tubular membrane, and suctions the hollow portion of each membrane. The present invention relates to a membrane separation device using a hollow tubular membrane that applies suction force of a pump and collects permeated water that has passed through the membrane and flowed into the hollow portion by the suction force.

[0002]

2. Description of the Related Art The inventor of the present patent application has filed Japanese Patent Application No.
In No. 2806, a little above the bottom of the vertical cylindrical case is closed with a potting part, and the upper part of the potting part is used as a separation chamber, and the lower end of the hollow tubular membrane is attached to this potting part, and the lower end of the hollow part of the membrane is attached. The bottom of the cylindrical case is closed with the bottom plate away from the potting part, and the permeated water that has passed through the hollow tubular membrane and flowed into the hollow part between the potting part and the bottom plate. Using a membrane element having a chamber formed therein, raw water mixed with air bubbles is supplied under pressure to a separation chamber on a potting portion containing the hollow tubular membrane in the cylindrical case, and the water is collected through the hollow tubular membrane. We proposed a membrane separation device using a hollow tubular membrane that draws water by suctioning the permeated water flowing down to a suction pump.

[0003]

The above-mentioned membrane separation device achieves a predetermined effect in terms of sampling of permeated water, but flows upward in the cylindrical case of the membrane element by the air lift effect of air bubbles. In order to overflow the concentrated water from the upper end of the cylindrical case into a downward flow, and to supply and circulate again from below the separation chamber, the membrane element having the cylindrical case is vertically longer than the cylindrical case, and the cylindrical case is formed. It is necessary to use a module outer cylinder with a large inner diameter to keep the space where the concentrated water faces downward, and to fix the membrane element concentrically in the module outer cylinder, which increases the installation space or hollow Since the tubular membrane is provided in the cylindrical case of the membrane element, there is a problem that the membrane filling area per module volume is small.

[0004]

SUMMARY OF THE INVENTION Accordingly, the present invention eliminates the above-mentioned problems of the prior proposal by eliminating the cylindrical case of the membrane element and accommodating a large number of hollow tubular membranes constituting the membrane element in a module outer cylinder. It has been resolved.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS For this reason, the membrane separation device using a hollow tubular membrane of the present invention has a small-diameter lower cylinder portion in the lower half and a large-diameter gas-liquid separation cylinder portion in the upper half concentrically. A module outer cylinder provided with an annular water collecting seat provided in the gas-liquid separation cylindrical part located above the lower cylindrical part, a potting portion fitted and fixed to the annular water collecting seat, The upper end is fixed and hangs down to the inside of the lower cylindrical part, the dividing wall dividing the inside of the lower cylindrical part into two flow paths, and the upper end is fixed to the potting part, and the hollow upper end is on the upper surface of the potting part. A membrane element having a large number of external pressure type hollow tubular membranes that are open and hang down inside each of the two flow paths partitioned by the partition, and a raw water supply port at the bottom of the lower cylindrical portion; Compressed air alternately passes through two flow paths separated by the partition of the element Two gas supply ports are provided for supply, and a water sampling pipe for sampling permeated water permeated through the hollow portion of the hollow tubular membrane with a suction pump is connected to the annular water collecting seat in the gas-liquid separation cylinder, and the gas-liquid The separation tube is provided with an outlet for concentrated water that has not passed through the hollow tubular membrane. in this case,
It is preferable that the water sampling pipe also serves as a washing water supply pipe, and the raw water supply port also serves as a drainage port for washing drainage.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIGS. 1 to 3, reference numeral 10 denotes a module outer cylinder molded of plastic. A lower cylinder 11 having a small diameter in the lower half and a gas-liquid separation cylinder 12 having a large diameter in the upper half are concentric. The gas-liquid separation cylinder 12 is connected to the lower cylinder 11 by a downward tapered portion 12 ′ at the lower end. Further, the gas-liquid separation tube portion includes an annular water collecting seat 13 which has the same diameter as the lower tube portion 11 and is located above the lower tube portion, for example, below the inside thereof.

[0007] Reference numeral 20 denotes a membrane element.
3, a potting portion 21 fitted and fixed via an O-ring via an O-ring, an upper end fixed to the potting portion in a diametrical direction, and hanging down to below the inside of the lower tubular portion, thereby forming two insides of the lower tubular portion. A partition wall 22 for partitioning the flow passages a and b, and a hollow upper end fixed to the potting portion and having a hollow upper end opening to the upper surface of the potting portion, and drooping into two flow passages a and b partitioned by the partition wall And a large number of hollow tubular membranes 23. Each hollow tubular membrane 23 is a partition 2 in the illustrated embodiment.
The upper half is turned upward below the lower part 2, and one half of the turned up rises in one flow path a partitioned by the partition wall, and the other half rises in the other flow path b, and each upper end thereof is used as a potting part. Although it has a fixed U-shape, the upper end is fixed to the potting part, and one of them is drooping in the flow path a and the flow path b,
The lower end of the hollow portion may be closed.

[0008] As shown in FIG.
A sliding engagement device 19 composed of a vertical groove is provided on one of the diametrically opposed portions of the inner surface of the lower cylindrical portion 11 on which both side portions of the above-mentioned dividing wall are in sliding contact, and a vertical ridge is provided on the other. The partition wall 22 is slidably supported in a vertical direction inside the lower cylindrical portion. Since the upper part of the dividing wall 22 is located below the large-diameter gas-liquid separation cylindrical part 12 as shown in FIG. 2, the two flow paths a and b in the lower cylindrical part partitioned by the dividing wall are:
Two spaces c and d are formed between the upper ends on both sides of the dividing wall and the inner periphery below the gas-liquid separation tube.

At the bottom of the lower cylindrical portion of the module outer cylinder, a supply port 14 for raw water, an air supply port 15a for supplying air to the flow path a from below, and an air supply port 15b for supplying air to the flow path b from below. Are provided. An outlet 16 for concentrated water is provided near the open upper end of the gas-liquid separation tube 12.

In the embodiment shown in FIGS. 1 to 4, in order to support the annular water collecting seat 13 concentrically inside the gas-liquid separation cylinder 12, a support 17 having the annular water collecting seat 13 attached below is provided with a gas-liquid support. A water collecting chamber 13 ′ having an upward taper is provided at an upper portion of an inner periphery of an annular water collecting seat in which a potting portion of a membrane element is fitted on an inner periphery, and a lower end is provided at a top of the water collecting chamber 13 ′. And an inverted L-shaped water sampling pipe 18 which penetrates through the support 17 in the radial direction and opens on the side surface of the gas-liquid separation cylinder below the outlet 16 for the concentrated water.

In order to perform a water sampling operation for sampling permeated water, the suction pump P2 of the suction pipe 31 connected to the water sampling pipe 18 is operated to apply a suction force to all the hollow portions of the hollow tubular membrane 23, and By operating the water supply pump P1 of the water supply pipe 32 connected to the raw water supply port 14, the raw water is supplied into the lower cylindrical portion 11 from below, and at the same time, the compressed air source 33 such as a blower and an air compressor is operated to supply air. One of the valves V1 and V2 of the branch supply pipes 34a and 34b connected to 15a and 15b, for example, the valve V1 of 34a is opened, and one of the flows separated from the supply pipe 34a by the partition wall 22 via the supply port 15a. Air is supplied into the passage a from below.

As a result, the water supplied from the raw water supply port 14 and entering the flow channel a flows upward in the flow channel a by the air lift effect of the air bubbles supplied from below into the flow channel. When reaching the upper end of the flow path, the upper end of the other flow path b is passed through two spaces c and d formed between the upper ends on both sides of the partition wall and the inner periphery below the gas-liquid separation cylinder 12. Inflowing channel b
After flowing downward in the inside, it flows under the partition wall and flows into the lower end of the flow path a, and thus a circulating flow is generated between the flow paths a and b formed by the partition wall in the lower cylinder portion, The bubble rising inside a floats on the liquid surface of the gas-liquid separation cylinder 12. In this way, a part of the raw water circulating between the flow channels a and b permeates the membrane from the outside to the inside by a suction force acting on the hollow portion of the hollow tubular membrane, flows into the hollow portion as permeated water, and becomes hollow. The water collecting pipe 13 and the suction pipe 3
1. Water is collected via the suction pump P2. On the other hand, air bubbles that float in the flow path a toward the liquid surface of the gas-liquid separation cylinder are
The gap between the bundles of the hollow tubular membranes 23 hanging down is raised, a shearing force is applied to the outer surface of the membrane, and the gel layer attached to the outer surface of the membrane is peeled off. A gel layer adheres to the outer surface of the hollow tubular membrane in the channel b flowing downward.

The supply of air from the compressed air source is supplied to the air supply port 15.
a for a predetermined time (for example, 30 minutes), the branch air supply pipe 3
The valves V1 and V2 of the valves 4a and 34b are opened and closed, and the valve V2 is opened to supply air to the air supply port 15b.

As a result, the water supplied from the raw water supply port 14 and entering the flow path b flows upward in the flow path b by the air lift effect of the air bubbles supplied from below into the flow path. When reaching the upper end of the flow path, the upper end of the other flow path a is passed through two spaces c and d formed between the upper ends on both sides of the partition wall and the inner periphery below the gas-liquid separation tube 12. Inflowing channel a
After flowing downward through the inside, it flows under the partition wall and flows into the lower end of the flow path b, and thus a circulating flow is generated between the flow paths b and a formed by the partition wall in the lower cylindrical portion, and the flow path The bubble rising inside b rises to the liquid surface of the gas-liquid separation tube 12. In this way, a part of the raw water circulating between the flow paths b and a is partially permeated through the membrane from outside to outside by the suction force acting on the hollow part of the hollow tubular membrane, and flows into the hollow part as permeated water and becomes hollow. The water collecting pipe 13 and the suction pipe 3
1. Water is collected via the suction pump P2. On the other hand, air bubbles that float in the flow channel b toward the liquid surface of the gas-liquid separation cylinder are
The gap between the bundles of the hollow tubular membranes 23 hanging down is raised, a shearing force is applied to the outer surface of the membrane, and the gel layer attached to the outer surface of the membrane is peeled off. Note that a gel layer adheres to the outer surface of the hollow tubular membrane in the flow path a through which the raw water flows downward.

In this way, the supply of air from the compressed air source is switched to the flow paths a and b every 30 minutes, and the gel layer adhering to the outer surface of the hollow tubular membrane in the flow path in which the raw water flows downward alternately. Even if the water collecting operation is performed while separating, it is impossible to completely separate the gel layer.Therefore, a small amount of the gel layer that cannot be separated adheres to the outer surfaces of the hollow tubular membranes in both flow paths, and the gel layer remains. The head loss gradually rises due to accumulation. When the head loss exceeds a predetermined value, the supply of raw water by the water supply pump P1, the operation of the suction pump P2, and the supply of air by the compressed air source are stopped, and the washing water is added by the pump P3 to the water sampling pipe 18 and the washing water supply pipe 35. Cleaning is performed by supplying under pressure. As this washing water, permeated water collected during the water sampling operation is used. As a result, the washing water is injected under pressure from the water collecting chamber 13 ′ into the hollow portion of the hollow tubular membrane 23, and the gel layer attached to the outer surface of the membrane is removed when the membrane permeates from the inside to the outside. . The washing wastewater containing the separated gel layer is drained from a drain pipe 36 connected to the raw water supply port 14. If no gel layer is found in the liquid discharged from the drain pipe 36, the operation of the pump P3 is stopped to end the washing step, and the above-described operation of collecting permeated water is resumed.

In this case, as shown in FIG.
8, a suction pipe 31 having an on-off valve V3 and a washing water supply pipe 35 having an on-off valve V4 are branched and connected, and a raw water supply pipe 14 having an on-off valve V5 is connected to the raw water supply port 14.
And the drainage pipe 36 of the cleaning drain having the on-off valve V6 is branched and connected, so that the on-off valve V4,
V6 may be closed, and the on-off valves V3 and V5 may be closed during the cleaning process. The suction pipe 31 and the cleaning water supply pipe 35 may be individually connected to the water sampling pipe 18 or the raw water supply pipe 32 and the cleaning water supply pipe 32 may be closed. The trouble of individually connecting the water drain pipes 36 to the raw water outlets 14 can be omitted.

Further, if the gas-liquid separation tube portion 12 can be vertically separated at the level near the lower surface of the annular water collecting seat 13 by the flange joint 12a as shown in the figure, the flange joint can be replaced when the membrane element 20 is replaced. Is removed, the upper side 12b of the membrane element and the upper end 12b are disengaged upward by sliding the both sides of the partition wall 22 upward in the slide engagement device 19 of the lower cylindrical part, and the lower ends of the membrane and the partition wall come out from the lower part. Potting part 2 of membrane element
1 can be withdrawn from the catchment 13 and a new membrane element can be easily replaced by reversing the above operation. This also facilitates the work of assembling the membrane element when the device is completed.

The second embodiment shown in FIGS.
A plurality of radial arms 37 protrude from the outer periphery of the cylinder, and an annular support shelf 38 for supporting the arm 37 from below is provided on the inner periphery of the gas-liquid separation tube portion 12. By supporting the 37, the annular water collecting seat having the membrane element 20 mounted on the inner periphery thereof is concentrically supported inside the gas-liquid separation tube portion 12, and the partition wall 22 and the hollow tubular film 23 of the lower tube portion 11 are supported. The water collecting chamber 13 ′ of the annular water collecting seat 13 hangs down to the inside.
A suction pipe P2 having a suction pump P2 at the upper end thereof is provided with a water collecting pipe 18 having an open lower end at the top of the annular water collecting seat, the upper end of which is positioned above the open upper surface of the gas-liquid separation tube 12. Although the configuration is different from that of the first embodiment shown in FIGS. 1 to 4 in that a pipe 31 and a washing water supply pipe 35 having a pump P3 are connected, the operation of collecting permeated water is the same as in the first embodiment. In addition, the hollow tubular membrane can be washed.

In the first embodiment, a support 17 is provided which crosses the inside of the gas-liquid separation tube 12 in the diameter direction, and a water sampling pipe 18 is provided in the support 17 in the radial direction. , Formed separately from the lower or lower cylindrical portion 11 and assembled with a flange joint 12a.
In the second embodiment, a plurality of radial arms 37 are received on an annular support shelf 38 on the inner periphery of the gas-liquid separation unit, and
3 is concentrically supported in the gas-liquid separation section 12, and the water sampling pipe 18 is provided upright at the center of the upper surface of the annular water collecting seat 13, so that the module outer cylinder 10 can be integrally formed of plastic.

Accordingly, in the case of the second embodiment, the annular water collecting seat 13 is pulled out from the upper end of the gas-liquid separation cylinder 12 for each membrane element 20, and the potting portion is pulled out of the annular water collecting seat to remove the old membrane. Remove the element, replace the potting part of the new membrane element with the inner circumference of the annular water collecting seat, and insert the annular water collecting seat with the new membrane element inside the gas-liquid separation tube from the upper end. Arm 37 protruding from the outer circumference
May be concentrically received on the annular support shelf 38 on the inner periphery of the gas-liquid separation cylinder. This facilitates replacement of a new membrane element and facilitates the work of installing the membrane element at the beginning of the device.

In the first and second embodiments, the hollow tubular membrane is described as a hollow fiber membrane. However, when the hollow tubular membrane is a tubular membrane, the upper end of the membrane is fixed to the potting portion 21. The upper end of the hollow part is opened on the upper surface of the potting part, a part of the tubular membrane is dripped down to the flow path a, and the remaining tubular membrane is drooped to the flow path b, and the lower end of each tubular membrane is closed or fixed by potting. And close it.

[0022]

As is apparent from the above description, the present invention has a structure in which the lower half of the module outer cylinder is a small-diameter lower cylinder and the upper half is a large-diameter gas-liquid separation cylinder. The potting at the upper end of the membrane element was fitted and fixed to the annular water collecting seat provided concentrically with the hollow collecting membrane, and a number of hollow tubular membranes with the upper end fixed to the potting portion were suspended in the lower cylindrical portion. Can be significantly larger than the case where the hollow annular membrane is provided in the cylindrical case of the membrane element.
A partition wall whose upper end is fixed to the potting portion and hangs down is formed into two passages a and b except for the bottom portion inside the lower tubular portion.
The half of the tubular hollow membrane is positioned in the flow path a, and the other half is positioned in the flow path b. By supplying air to the flow paths a and b alternately from below, the flow path a The upward flow, the circulating flow flowing downward in the flow path b, and the upward flow flowing in the flow path b.
A circulating flow that flows downward in the flow path a can be formed, and permeated water can be collected from raw water that performs either of the circulating flows, and a hollow tubular shape is formed by the shearing force of bubbles for causing the raw water to flow upward. The gel layer adhering to the outer surface of the membrane can be peeled off. Then, the bubbles having the raw water flowing upward in the flow path a or b are separated and float inside the gas-liquid separation cylinder above the membrane element, so that the bubbles are entrained in the water flowing down the flow path. Therefore, a circulating flow due to the air lift action of the bubbles can be efficiently generated.

[Brief description of the drawings]

FIG. 1 is a vertical sectional side view of one embodiment of a membrane separation device according to the present invention.

FIG. 2 is a sectional view taken along line II-II in FIG.

FIG. 3 is a sectional view taken along line III-III in FIG. 1;

FIG. 4 is a sectional view taken along line IV-IV in FIG.

FIG. 5 is a vertical sectional side view of another embodiment of the membrane separation device according to the present invention.

FIG. 6 is a sectional view taken along line VI-VI in FIG. 5;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Module outer cylinder 11 Lower cylinder part of module outer cylinder 12 Gas-liquid separation cylinder part of module outer cylinder 13 Annular water collecting seat of module outer cylinder 13 'Water collecting chamber of module outer cylinder 14 Raw water supply port 15a Air supply port 15b Supply port 16 Concentrated water outlet 18 Sampling tube 20 Membrane element 21 Potting portion of membrane element 22 Partition wall of membrane element 23 Hollow tubular membrane of membrane element 31 Suction pipe for permeated water 32 Raw water supply pipe 33 Compressed air source 35 Cleaning Water supply pipe 36 Cleaning drainage pipe 37 Arm 38 Support shelf a One flow path in the lower cylinder part partitioned by the partition wall b The other flow path in the lower cylinder part partitioned by the partition wall C Upper part of the partition wall A space connecting the flow paths a and b in the space D A space connecting the flow paths a and b in the upper part of the partition wall P1 Supply pump for raw water P2 Suction pump for permeated water P3 Supply pump for washing water

Claims (1)

[Claims] 1. A lower-diameter lower cylinder portion in a lower half portion and a large-diameter gas-liquid separation cylinder portion in a upper half portion concentrically, and located above the lower cylinder portion in the gas-liquid separation cylinder portion. A module outer cylinder provided with an annular water collecting seat provided in, a potting portion fitted and fixed to the annular water collecting seat, the upper end is fixed to the potting portion and hangs down to the lower inside of the lower cylindrical portion, A partition wall dividing the inside of the lower cylindrical portion into two flow paths, and an upper end fixed to the potting portion, a hollow upper end is opened on the upper surface of the potting portion, and the inside of each of the two flow paths partitioned by the partition wall A membrane element having a large number of external pressure type hollow tubular membranes hanging down to the bottom of the lower cylindrical portion, and a compressed air is alternately supplied to a raw water supply port and two flow paths separated by a partition of the membrane element. Two gas supply ports for supplying A water sampling pipe is connected to the water seat for sampling permeated water permeated through the hollow portion of the hollow tubular membrane with a suction pump, and an outlet for concentrated water that has not passed through the hollow tubular membrane is connected to the gas-liquid separation cylinder. A membrane separation device using a hollow tubular membrane, provided.