JP4230569B2 - Hollow fiber membrane module - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a hollow fiber membrane module that can be suitably used for high-contamination treatment after sand filtration, in addition to filtration of highly pollutant liquids such as river water and lake water filtration, industrial water filtration, and wastewater treatment.
[0002]
[Prior art]
Hollow fiber membrane modules are used in the fields of microfiltration such as the production of aseptic water, high-purity water, drinking water, and air purification, as well as secondary and tertiary treatment in sewage treatment plants, and solid-liquid separation in septic tanks, etc. It is also applied to the field of highly polluted water treatment.
[0003]
In highly polluted water treatment, clogging during filtration is often large. In this case, after filtration treatment is performed for a certain period of time, air is sent from the bottom of the module to vibrate the hollow fiber membrane and wash the membrane surface. A scrubbing operation to be performed and membrane cleaning such as reverse cleaning to pass water in a direction opposite to the filtration direction are repeatedly performed.
[0004]
However, when a hollow fiber membrane module in which hollow fiber membrane knitted fabrics are converged and arranged in a columnar shape or concentric shape used for conventional microfiltration is used for highly polluting water treatment, the membrane will increase with the passage of treatment time. The hollow fiber membranes adhere to each other due to deposits such as organic substances adhering to the surface, the effective area of the hollow fiber membrane in the module is reduced, the filtration flow rate is drastically reduced, and the membrane is periodically cleaned. However, the membrane function could not be easily recovered and the filtration efficiency could be significantly reduced.
[0005]
As a solution to the problem of the reduction of the effective area and the cleaning efficiency, the hollow fiber membrane knitted fabric is spread in a filter screen shape, and the hollow fiber membrane at one end or both ends is fixed to the frame while keeping the open state. A flat hollow fiber membrane module with a rectangular cross section has been proposed. By arranging a plurality of these hollow fiber membrane modules at appropriate intervals, the membrane surface can be easily cleaned and the reduction in filtration efficiency can be suppressed. It became.
[0006]
In this flat type hollow fiber membrane module, the secondary side of the filtration membrane is often sucked to perform a filtration operation, and in order to obtain higher filtration performance, the hollow fiber membrane module is stored in a pressure vessel such as a cylindrical container. Then, the primary side of the filtration membrane is further pressurized to perform filtration.
[0007]
However, when a flat hollow fiber membrane module is housed in a cylindrical container, the proportion occupied by parts other than the hollow fiber membrane increases, so the volumetric efficiency deteriorates. Container costs, such as the need for members, are expensive.
[0008]
[Problems to be solved by the invention]
As a structure for solving the above volume efficiency problem, a plurality of flat hollow fiber membrane knitted fabrics are arranged in parallel or zigzag to form a hollow fiber membrane module, which is supplied from an air header. A hollow fiber membrane module capable of maintaining a high filtration function over a long period of time by scrubbing with fresh air has been proposed in JP-A-9-14163.
[0009]
However, in the hollow fiber membrane module, the supplied air does not flow uniformly between the hollow fiber membrane knitted fabrics, and drift occurs, or a plurality of air bubbles rise together and rise as large bubbles. There was something to do. Due to this phenomenon, the entire surface of the hollow fiber membrane is not washed, so that a more uniform recovery of the filtration function cannot be sufficiently achieved, or it is necessary to supply more air than necessary.
[0010]
In order to solve such a problem, an aeration nozzle is disposed between the laminates near the upper surface of the lower fixing member of the hollow fiber membrane knitted fabric arranged in parallel in the vertical direction, and the hollow fiber membrane knitted fabric is interposed between the hollow fiber membrane knitted fabrics. Japanese Patent Application No. 9-158416 has been filed for a hollow fiber membrane module having improved detergency by reliably supplying air. By adopting the structure in which this air diffuser nozzle is disposed, it has become possible to maintain a high filtration function for a long period of time. However, when each component is mounted on the can body, it is necessary to connect the air pipe to the diffuser nozzle, and the can body needs an opening for the connection work and a lower treated water outlet pipe. Therefore, there has been a problem to be improved when the filtration cost is further reduced, such as a complicated can body structure.
[0011]
An object of the present invention is to reliably supply scrubbing air between filtration screens made of a hollow fiber membrane knitted fabric in a hollow fiber membrane module having a structure in which a filtration screen made of a hollow fiber membrane knitted fabric is provided in a can body container. To provide a hollow fiber membrane module that can perform more uniform and efficient cleaning, has a simple structure, can be easily attached and detached, and has good workability and work efficiency in maintenance management. is there.
[0012]
[Means for Solving the Problems]
The hollow fiber membrane module of the present invention is
A filtration screen comprising a hollow fiber membrane knitted fabric;
An upper fixing member for fixing the upper end of the filtration screen while maintaining the open state of the upper end of each hollow fiber membrane constituting the hollow fiber membrane knitted fabric;
A lower fixing member for fixing the lower end of the filtration screen while maintaining the open state of the lower end of each hollow fiber membrane constituting the hollow fiber membrane knitted fabric;
A water conduit that passes through the upper fixing member and the lower fixing member, and communicates the side of the upper fixing member where the upper ends of the hollow fiber membranes open and the side of the lower fixing member where the lower ends of the hollow fiber membranes open. ,
Air release means provided in the vicinity of the upper fixing member side surface of the lower fixing member;
A gas passage communicating with an air supply port provided on an edge side surface of the upper fixing member and having an opening on the lower fixing member side;
An opening for connecting the opening on the lower fixing member side of the gas passage to the air releasing means, and a lower end of each hollow fiber membrane of the lower fixing member for venting from the air supply port to the air releasing means A partition member for partitioning a region including the surface on the opening side, and forming a lower treatment water chamber;
By inserting and arranging a filtration element having a
The can body container includes a surface on the side where each hollow fiber membrane of the upper fixing member is opened, communicated with a treated water outlet, and communicated with the lower treated water chamber and the conduit pipe; A side surface of each hollow fiber membrane that is formed as a region separated from the upper treatment water chamber and the lower treatment water chamber, and that constitutes the hollow fiber membrane knitted fabric, is provided with a treated water supply port and an air outlet; A treated water chamber communicating with the
And the said upper fixing member has been arrange | positioned so that the said air supply port may be opened toward the exterior of this can body container, It is characterized by the above-mentioned.
[0013]
According to the present invention, it is possible to uniformly and surely supply the scrubbing air to the filtration screen of the hollow fiber membrane knitted fabric, and the configuration is simplified, and each component is also efficiently arranged. Therefore, good operability and workability can be obtained.
[0014]
The air release means in the hollow fiber membrane module of the present invention has a structure in which a slit member penetrating from the front surface to the back surface is provided in a disk-like member having an air discharge hole, and the filtration screen of the hollow fiber membrane knitted fabric is provided in the slit By incorporating it in the vicinity of the upper surface of the lower fixing member in a state where the is inserted, a more effective ventilation effect can be obtained.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic cross-sectional view showing an example of the hollow fiber membrane module of the present invention. This hollow fiber membrane module has a configuration in which a plurality of filtration screens 1 made of hollow fiber membrane knitted fabric are arranged in parallel at predetermined intervals in a can body container mainly composed of a can body 3 and a cap 4. Have. The upper end and the lower end of each hollow fiber membrane constituting the hollow fiber membrane knitted fabric are fixed to the upper fixing member 2b and the lower fixing member 2a, respectively, while maintaining an open state. These fixing members separate the treated water chambers 14 and 15 including the surface on the side where the open end of each hollow fiber membrane is opened, and the treated water chamber 16 including a space where the side surface of each hollow fiber membrane is located. Functions as part of the partition wall. The lower treated water chamber 15 is partitioned by a lower fixing member 2a and an element cap 11 as a partition member, and is configured as a region where the lower open end of each hollow fiber membrane opens.
[0016]
Between the two fixing members, there is provided a water conduit 12 that passes through these fixed members and communicates between the upper and lower treated water chambers 14, 15, and the lower treated water chamber 15 is provided by the water conduit 12. The treated water is guided to the upper treated water chamber 14 and finally taken out from the treated water outlet 6 to the outside of the module.
[0017]
The upper fixing member 2b has an edge portion having the same outer diameter as that of the can body 3 and the cap 4, and an air supply port 8 is opened on a side surface of the edge portion. The air supply port 8 communicates with a gas passage 17 having an opening on the lower fixing member side, and connects the gas passage 17 and an air discharge means 9 provided near the upper surface of the lower fixing member 2a ( The air discharge means 9 can be ventilated through an air pipe 13. The air discharge means 9 has a slit-like through hole having an air discharge hole, and each filtration screen 1 is inserted into the through hole.
[0018]
In the hollow fiber membrane module having the structure shown in FIG. 1, the assembly (element) comprising the filtration screen 1, the fixing members 2a and 2b, the air discharge means 9, the element cap 11, the water guide pipe 12, the air pipe 13 and the like is a can body. 3 is inserted from above and fixed so that the upper part is closed by a cap 4. In this way, by supplying an element that can be assembled in a completed state before it is stored in the can body container, the element after assembly is arranged in the can body 3 and fixed with the cap 4. The assembly of the hollow fiber membrane module can be completed with a simple operation, and work such as periodic replacement of elements can be performed with good workability. Such good handling and workability can be achieved by a compact element structure in which the air pipe 13, the water guide pipe 12, the air discharge means 9 and the like are efficiently arranged with respect to the two fixing members.
[0019]
On the other hand, the can body 3 is provided with a treated water supply port 5, a deposit outlet 7 and an air outlet 10, and the cap 4 is provided with a treated water outlet 6.
[0020]
FIG. 2 is a schematic plan view showing the structure of an example of the air discharge means, and FIG. 3 is a sectional view thereof. For the sake of explanation, the positional relationship between the slits and the air discharge holes in FIG. 3 is different from that in FIG.
[0021]
2 and 3, the air discharge means 9 has a disk-like shape with an outer diameter corresponding to the lower fixing member 2 a, and an inner space (cavity; provided in FIG. 2 by a broken line). ) 20 has a function as an air disperser. The base portion of the filtration screen 1 is inserted into each slit 21, and an air discharge hole 19 provided in the slit 21 opens toward this.
[0022]
The treatment of water to be treated in the hollow fiber membrane module having the structure shown in FIGS. 1 to 3 can be performed as follows, for example. First, the air outlet 10 and the deposit outlet 7 are closed by appropriate means, and the water to be treated is introduced into the water chamber 16 to be treated from the water supply port 5 to be treated. The treated water introduced into the treated water chamber 16 comes into contact with the side surface of the hollow fiber membrane in the hollow fiber membrane knitted fabric constituting the filtration screen 1 and passes through the hollow fiber membrane to filter the solid matter. The The treated water after filtration flows from the hollow portion of the hollow fiber membrane to the treated water chambers 14 and 15, and the treated water in the treated water chamber 15 is guided to the treated water chamber 14 via the water conduit 12. Finally, it is taken out from the treated water outlet 6 to the outside of the module. If necessary, suction from the treated water outlet 6 side and pressurization from the treated water supply port 5 side can be used in combination.
[0023]
Moreover, the washing operation of the filtration screen 1 can be performed as follows, for example. After the filtration treatment for a predetermined time, the supply of the treated water is stopped, the treated water chamber 16 is filled with the treated water, the air outlet 10 is released, and then the scrubbing from the air supply port 8 is performed. Supply air. The supplied air passes through the gas passage 15 and the air pipe 13 and is jetted toward the root portion of each filter screen 1 by the air discharge means 9. The sprayed scrubbing air forms bubbles, rises while washing the surface of the hollow fiber membrane knitted fabric constituting the filtration screen 1 between the filtration screens 1, and is discharged out of the system from the air outlet 10. The solid material peeled off from the surface of each hollow fiber membrane by this scrubbing operation settles at the bottom of the can 3 to form a deposit. This deposit can be discharged out of the system from the deposit outlet 7.
[0024]
As the hollow fiber membrane constituting the hollow fiber membrane knitted fabric used in the present invention, those made of various materials such as polyolefin-based, cellulose-based, polyvinyl alcohol-based, polysulfone-based, polymethyl methacrylate-based, and composites thereof are used. Olefin-based hollow fiber membranes such as polyethylene having a high strength and elongation are preferably used from the standpoint of knitting fabric properties to knitted fabrics and response to shaking by air for scrubbing. Moreover, if a hollow fiber membrane can be used as a filtration membrane, there will be no restriction | limiting in particular in a hole diameter, a porosity, a film thickness, an outer diameter, etc.
[0025]
The hollow fiber membrane knitted fabric may be based on any knitting method or weaving method as long as the hollow fiber membrane is disposed on one of the warp and the weft and the function as a filtration membrane is maintained. .
[0026]
The hollow fiber membrane knitted fabric is developed in a screen shape to form a filtration screen 1, and a plurality of them are arranged in parallel. 3-50 mm is preferable and, as for the pitch between each filtration screen, 5-20 mm is more preferable. When the pitch is 3 mm or less, there is a case where the solid matter peeled from the side surface of the hollow fiber membrane gets caught between the filtration screens when the deposit after scrubbing is discharged, and the probability of remaining there increases. Then, there may be a case where a sufficient membrane area can be taken in the hollow fiber membrane module.
[0027]
The upper fixing members 2a and 2b function as members that fix the hollow fiber membrane knitted fabric and partition the treated water and the treated water without leakage, and are formed of, for example, a urethane resin, an epoxy resin, an unsaturated polyester resin, or the like. can do. The hollow fiber membrane can be fixed to these fixing members by a conventional method.
[0028]
As described above, the upper fixing member 2 b has a function of fixing the element by sandwiching the outer peripheral portion (edge portion) between the can body 3 and the cap 4. These can be fixed by various fixing means such as a combination of a bolt and a nut using a flange structure as shown in the figure, for example.
[0029]
Further, as described above, the upper fixing member 2 b has the air supply port 8 for supplying the scrubbing air on the outer peripheral side wall, and the connection port with the air pipe 13 of the gas passage 15 communicating with the air supply port 8. Is provided toward the treated water chamber on the side surface side of the hollow fiber membrane. This scrubbing air supply structure eliminates the need to connect the air piping from the outside of the can to the air release means when installing the element in the can in the conventional structure, greatly simplifying the element installation work. In addition, the opening for connecting the can body can be omitted.
[0030]
The element cap 11 is fixed to the lower fixing member 2a without leakage from the outside, and a treated water chamber 15 is formed by these members. The portion collected in the treated water chamber 15 with the treated water filtered by the hollow fiber membrane is guided to the upper treated water chamber 14 by the water conduit 12.
[0031]
The thickness of each fixing member can be selected according to the strength of the material constituting the fixing member, the combined use of a reinforcing member, etc., and the fixing member diameter is preferably R, and is preferably 0.1R to 1R, 0.6R is more preferable. If it is less than 0.1R, it may be difficult to ensure pressure resistance, and if it exceeds 1R, an excessive amount of constituent material such as resin may be required.
[0032]
The element cap 11 can be made of a material such as resin or metal in consideration of pressure resistance, water resistance, corrosion resistance, elution resistance, and the like, and is well-known such as bonding to the fixing member 2a or an O-ring. It is fixed without leakage using a member.
[0033]
The water conduit 12 can be made of a material such as resin or metal in consideration of pressure resistance, water resistance, corrosion resistance, elution resistance, adhesion to a fixing member, and the like, depending on the amount of liquid to be processed. The hole diameter and the number of installation can be selected as appropriate.
[0034]
The air discharge means 9 can be made of a material such as resin or metal in consideration of pressure resistance, water resistance, corrosion resistance, workability, etc., and its fixing position can provide a good cleaning effect by scrubbing. For example, it can be in the vicinity of the upper surface of the lower fixing portion 2a. Various fixing means can be used to fix the position of the air discharge means 9, but as shown in the figure, the method of fixing the arrangement position via the fixing portion with the water conduit 12 is the structure of the element. It is preferable for simplifying.
[0035]
The shape and size of the slit provided in the air discharge means 9 can be set in consideration of the shape and arrangement pitch of the filtration screen 1 and the cleaning effect. Further, the position of the air discharge hole is not particularly limited as long as it can be satisfactorily cleaned by scrubbing. In consideration of the uniformity of the air supply to the filtration screen 1 and the treatment of the solid matter accumulated in the slit, it is preferable that the filter is provided on the inner wall of the slit as shown in FIGS. 2 and 3, the arrangement pitch of the air discharge holes 19 in the case of being provided on the inner wall of the slit is preferably 10 mm to 70 mm in consideration of the uniformity of bubble formation. If it is smaller than 10 mm, the supply of bubbles may be excessive, and if it is larger than 70 mm, uneven cleaning may occur in the washing of the hollow fiber knitted fabric due to the bubbles. For the air discharge holes 19, the number of holes, hole diameter, pitch, etc. can be set according to the turbidity, turbidity characteristics, cleaning conditions, etc. of the water to be treated. For example, the hole diameter is 0.5 to 5 mm. Preferably, it can be 1 to 3 mm. If it is less than 0.5 mm, clogging is likely to occur. If it exceeds 5 mm, it is difficult to balance the discharge amount between the holes, and excessive scrubbing air may be required.
[0036]
The container mainly composed of the can body 3 and the cap 4 preferably has a cylindrical portion in order to ensure pressure resistance. Resin in consideration of pressure resistance, water resistance, corrosion resistance, elution resistance, etc. It can consist of materials, such as a metal. Further, the can 3 may have a structure that can be separated at appropriate portions.
[0037]
【The invention's effect】
The hollow fiber membrane module of the present invention can perform uniform and efficient cleaning by supplying the scrubbing air between filtration screens made of hollow fiber membrane knitted fabric, and can maintain high filtration efficiency over a long period of time. In addition, it is easy to attach and detach an element having a filtration screen or the like into the can body container, and the structure of the can body container itself can be simplified.
[Brief description of the drawings]
FIG. 1 is a schematic cross-sectional view showing an example of an embodiment of the present invention.
FIG. 2 is a schematic plan view of an example of air release means that can be used in the present invention.
FIG. 3 is a schematic cross-sectional view of an example of air release means that can be used in the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Filtration screen 2a Lower fixing member 2b Upper fixing member 3 Can body 4 Cap 5 To-be-processed water supply port 6 Treated water outlet 7 Deposit outlet 8 Air supply port 9 Air discharge means 10 Air outlet 11 Element cap 12 Water guide pipe 13 Air pipe 14 Upper treated water chamber 15 Lower treated water chamber 16 Treated water chamber 17 Gas passage 18 Air pipe connection portion 19 Air discharge hole 20 Cavity portion 21 Slit

Claims (4)

A filtration screen comprising a hollow fiber membrane knitted fabric;
An upper fixing member for fixing the upper end of the filtration screen while maintaining the open state of the upper end of each hollow fiber membrane constituting the hollow fiber membrane knitted fabric;
A lower fixing member for fixing the lower end of the filtration screen while maintaining the open state of the lower end of each hollow fiber membrane constituting the hollow fiber membrane knitted fabric;
A water conduit that passes through the upper fixing member and the lower fixing member, and communicates the side of the upper fixing member where the upper ends of the hollow fiber membranes open and the side of the lower fixing member where the lower ends of the hollow fiber membranes open. ,
Air release means provided in the vicinity of the upper fixing member side surface of the lower fixing member;
A gas passage communicating with an air supply port provided on an edge side surface of the upper fixing member and having an opening on the lower fixing member side;
An opening for connecting the opening on the lower fixing member side of the gas passage to the air releasing means, and a lower end of each hollow fiber membrane of the lower fixing member for venting from the air supply port to the air releasing means A partition member for partitioning a region including the surface on the opening side, and forming a lower treatment water chamber;
By inserting and arranging a filtration element having a
The can body container includes a surface on the side where each hollow fiber membrane of the upper fixing member is opened, communicated with a treated water outlet, and communicated with the lower treated water chamber and the conduit pipe; A side surface of each hollow fiber membrane that is formed as a region separated from the upper treatment water chamber and the lower treatment water chamber, and that constitutes the hollow fiber membrane knitted fabric, is provided with a treated water supply port and an air outlet; A treated water chamber communicating with the
The hollow fiber membrane filtration module is characterized in that the upper fixing member is disposed so as to open the air supply port toward the outside of the can body container. The air discharge means has a structure in which a slit that passes through the disk-shaped member perpendicular to the radial direction of the disk-shaped member is provided in a disk-shaped member having an air discharge hole, and the filtration is provided in the slit. The hollow fiber membrane module according to claim 1, wherein the hollow fiber membrane module is disposed through a screen. The hollow fiber according to claim 1 or 2, wherein an edge side surface of the upper fixing member constitutes a part of an outer wall surface of the can container, and the air supply port is disposed on the edge side surface. Membrane module. The hollow fiber membrane module according to any one of claims 1 to 3 , wherein a plurality of the filtration screens are arranged in parallel at a predetermined interval.

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