JPH09103655A - Hollow fiber membrane filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a hollow fiber membrane module from being separated from both attachment parts during backwashing by a method in which the filtrate outlet side of the module is attached detachably to a partition plate through an O-ring from a filter cell side, the other end of the module is attached detachably to a fixing plate from the filter cell side, and both ends of the module are fixed. SOLUTION: A standard type filter module M, a hole 26 formed in a partition plate 14 separating a filter cell 11 and a filter cell 12, is attached through an O-ring. The partition plate 14 is equipped with a bubble discharge mechanism 24 and a bubble outlet 25. In the main pipe 16 of the filter cell 11, a flange joint 21 is connected with both ends of a rigid polyvinyl chloride pipe for city water, a fixing plate is arranged to attach the lower end of the module M. By fixing the upper and lower parts of the module M to the partition plate 14 and a fixing plate 15, backwashing can be done without falling from the partition plate 14. In this way, an economical apparatus is made which uses a standard type hollow fiber membrane module having a filtration capacity recovery mechanism suitable for middle scale filtration.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention uses a hollow fiber membrane module, which is a cartridge filter of a fixed design, and uses JIS standard tubes and joints compatible with these tubes as main components of the module housing. While
The present invention relates to an economical filtration device capable of backwashing and air bubbling.

[0002]

2. Description of the Related Art Conventionally, since the filtration area becomes advantageous,
When the hollow fiber membrane is used for the total filtration, an external pressure type filtration method of filtering from the outside to the inside of the hollow fiber membrane is often adopted. If filtration is continued, the substance removed will accumulate on the surface of the hollow fiber membrane, and the filtration rate will gradually decrease.

A method of backwashing by flowing a liquid such as a filtrate or a gas such as air from the inside to the outside of the hollow fiber membrane in order to remove the accumulated substances from the membrane surface and restore the filtration ability again (for example, JP 58-20206 A, JP 5
JP-A-8-183916), a method of stirring bubbles (air bubbling) in a hollow fiber membrane container by causing bubbles to flow outside the hollow fiber membrane (for example, JP-A-61-153104).
JP-A-61-222509, JP-A-61-221
No. 254207), a method in which backwashing and air bubbling are used in combination (JP-A-62-4408 and JP-A-62-62).
No. 262709) was devised. All of these are excellent methods that effectively restore filtration capacity,
Helps to significantly extend filtration life.

[0004] These filtration devices have an efficient structure in a special case where a large amount of filtration is required. In both cases, a hollow fiber membrane module is mounted in a suspension type on a partition plate that partitions the filtration chamber and the filtrate chamber. The structure is such that each one is detached from the upper filtration chamber side.

On the other hand, as a filtration module for performing a relatively small amount of filtration which cannot be backwashed, as is well known to those skilled in the art, a flat membrane has long been folded into a pleated shape, and the outer dimensions have been determined by the manufacturer. Regardless, many so-called economical fixed cartridge filters that have been housed in a structure of common design have been used. A module incorporating a hollow fiber membrane compatible with these fixed-type cartridge filters was also devised by the same person as the present inventor (JP-A-2-227125, JP-A-6-1821).
No. 61 publication).

[0006]

As described above, a filtering device using a large-sized module suitable for large-scale filtration having a recovery mechanism of filtration capacity and a fixed-type module for small-volume filtration having no recovery mechanism of filtration capacity are used. Although there is such a filtering device, an economical filtering device utilizing a fixed type module having a filtering capacity recovery mechanism suitable for medium-scale filtration has not yet been devised.

The conventional filtering device using a fixed type module does not have a filtration capacity recovery mechanism such as backwash as described above, but the fixed type module using a hollow fiber membrane originally has a filtering capacity recovery function. Therefore, if the housing for mounting them can be provided with such a mechanism, the above problems can be solved.

[0008]

Means for Solving the Problems That is, in order to solve the above-mentioned problems, the present invention provides an “external pressure type filtration device for filtering from the outside to the inside of a hollow fiber membrane, which has an inlet for a liquid to be treated, a bubble The partition plate that separates the lower filtration chamber having the supply mechanism and the air bubble discharge mechanism from the upper filtration liquid chamber having the filtrate outlet, and is detachably attached from the filtration chamber side via the O-ring. The hollow fiber membrane module whose design is a fixed-shape cartridge filter is equipped with a filtrate outlet side, and the other end of the module is fixed to a fixed plate having a hole communicating with an inlet of the liquid to be treated and a bubble supply mechanism. The hollow fiber membrane filtration device is characterized in that the hollow fiber membrane module is detachably mounted from the side and the hollow fiber membrane module is fixed at both ends so that the hollow fiber membrane module does not detach from both mounting parts even during backwashing. " To do.

The present invention utilizes JIS standard pipes and fittings compatible with these pipes, more preferably stainless steel, and more preferably rigid polyvinyl chloride pipes and fittings as main members of the hollow fiber membrane housing. By doing so, it becomes more economical.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an example of a fixed-type hollow fiber membrane module M that can be used in the present invention. The hollow fiber membrane module M has an outer shape of about 70 mm, and generally has three types of lengths of about 25, 50, and 75 cm. A brief description will be given of a conventional method of using a fixed-type filtration module, but a conventional housing for mounting the module is well known to those skilled in the art, and therefore the illustration thereof is omitted.

The hollow fiber membrane module M will be briefly described. A bundle of hollow fiber membranes 1 folded back in a loop at the central portion is heated at one end portion of a cylinder 2 with heat such as urethane resin or epoxy resin. Potting is carried out by the focusing and fixing part 3 made of a curable resin, and the end of the hollow fiber membrane 1 has the focusing and fixing part 3
The header 4 is fixed to the end portion of the cylinder 2 which is open at the end surface of the cylinder 2. The liquid to be treated supplied to the surface of the hollow fiber membrane 1 through the hole 5 and the hole 6 in the bottom of the cylinder 2 is filtered from the outer side to the inner side of the hollow fiber membrane 1, and the filtrate is collected in the focusing fixing part 3. It gathers from the tip to the outlet 7 of the header 4 and is taken out from the filtrate outlet of the housing. Here, the hollow fiber membrane module M is attached to a partitioning mechanism that divides a filtrate chamber and a filtrate chamber of the housing via an O-ring 8 provided in the header 4. This housing does not have a backwash function or an air bubbling function.

This module can be used in the present invention as it is, but can be modified such as using a part of the structure, for example, the bottom with the shape of the hole 6 changed or the cylinder 2 with the shape of the hole 5 changed. Is. Further, there is no limitation on the material, size, pore diameter, etc. of the hollow fiber membrane 1.

(Example 1) Description of a filtering device of the present invention according to a specific example

FIG. 2 is a schematic view showing an example of the filtration device 10 of the present invention in which one hollow fiber membrane module M is mounted. The constituent materials of the housing are all JIS standard hard polyvinyl chloride pipes and their joints.

That is, one fixed-type filtration module M shown in FIG. 1 having a total length of 75 cm is attached to a hole 26 provided in a partition plate 14 for partitioning the filtration chamber 11 and the filtrate chamber 12 through an O-ring. ing. The partition plate 14 is also provided with a bubble discharging mechanism 24 and a bubble outlet 25.

The main pipe 16 of the filtration chamber 11 is a rigid polyvinyl chloride pipe for water supply having a JIS standard nominal diameter of 100 A, to which flange joints 21 are connected, and a hole 27 for introducing the liquid to be treated is provided at the lower end thereof. The lower end of the module M is mounted by disposing the fixing plate 15 having the module. A plurality of introduction holes 28 for the liquid to be treated are also provided around the hole 27.

The fixed plate 15 also has a bubble supply mechanism 22 and a gas inlet 23. The bubble supply mechanism 22 is made of a metal pipe and has a diameter of 0.
Blow-out holes for air bubbles of 5 to 2 mm are opened.

The filtrate chamber 12 is composed of a partition plate 14 and an elbow having flange joints 17 and 19 at both ends. Similarly to the filtrate outlet passage (filtrate chamber 12), the liquid to be treated introduction passage 13 is also constituted by an elbow which is flange joints 18 and 20.

The module M is at least 300 KPa
Since it has the strength to withstand the backwashing pressure of the module M, by fixing the top and bottom with the partition plate 14 and the fixing plate 15,
The backwash can be performed without falling off from the hole 26 of the partition plate 14.

When the module M is taken out, first, the bolts for fixing the main pipe flange 21, the partition plate flange 14 and the filtrate chamber flange 17 are removed, and the fixing bolts for the outlet flange 19 are removed to remove the filtrate chamber 12 (elbow). Next, the module M mounted on the partition plate 14 is pulled out from the main pipe 16, and then the module M is removed from the partition plate 14.

On the contrary, when mounting the module M, first, the module M is inserted into the main pipe 16 having an open upper part, and the lower end thereof is placed in the mounting hole 27 of the fixing plate 15. Next, after aligning the filtrate outlet 7 of the module M with the mounting hole 26 of the partition plate 14, the partition plate 14 is pushed in. Again, the filtrate flange 17 is overlaid and bolted, and the outlet flange 19 is also bolted.

Example of use of the filtration device of the present invention

FIG. 3 is an explanatory view of a method of using the filtration device of FIG. The test liquid is a 100 ppm aqueous dispersion of colloidal silica having an average particle size of 0.19 μm. The hollow fiber membrane is made of polysulfone, has an inner diameter of 500 μm, an outer diameter of 800 μm, a pore size that does not allow the colloidal silica to pass through, and a bubble point of air when an aqueous 30% by volume ethanol solution is included. Is about 500 KP
a. Module M uses about 1
The effective membrane area filled with 600 pieces is about 5.5 m ² .

The aqueous dispersion of colloidal silica was contained in a tank 100 having a volume of about 200 L (liter) and was constantly stirred by a stirrer 101. When the test solution was low, the same test solution was added.

First, the valve 112 for supplying the liquid to be treated and the valve 113 for discharging the filtrate are opened, and the test liquid is pumped by adjusting the valve 111 so that the flow rate of the filtrate flow meter 106 becomes 20 L / min. At 102, it was sent to the filtration device 10. During this time, the pressurized air valves 114 and 115, the bubble outlet valve 116, and the cleaning liquid discharge valve 117 were closed.

Then, the inlet pressure of the liquid to be treated and the pressure of the filtrate were measured by pressure gauges 109 and 110, respectively, and the head pressure difference was corrected to represent the net filtration pressure. Filtration showed a typical scale filtration mechanism, and the filtration pressure increased linearly from about 10 KPa immediately after the start of filtration and reached 50 KPa after about 1100 L filtration. Pump 102 at this point
Was stopped and valves 112 and 113 were closed.

Then, the valve 116 is opened, the pressurized air of about 100 KPa stored in the cylinder 103 of the air compressor is opened in the valve 114, and the filtrate chamber 12 (see FIG. 2) is opened.
Approximately 1 L of the filtrate in (see (1)) was flowed from the direction opposite to the filtration direction, and the backwash liquid was received in the tank 104. Next, flow meter 1
The valve 115 so that the flow rate of 07 becomes 4 NL / min.
Was adjusted, air was flowed from the nozzle 22 (see FIG. 2) at the bottom of the module for 1 minute, and then the valves 115 and 114 were closed. The cleaning liquid was collected in the tank 105 by opening the valve 117, but the discharged liquid was opaque and cloudy.

The valves were returned to the state at the time of filtration, and filtration was performed again under the same conditions. The initial filtration pressure recovered only up to about 20 KPa as compared with the initial filtration pressure, but the subsequent filtration pressure showed almost the same rise process as the initial filtration pressure, about 69 KPa.
It reached 50 KPa after 0 L filtration. Then, backwashing and air bubbling similar to the above were repeated and then the third filtration was performed, but the same process as above was shown.

(Embodiment 2) Description of a filtration device of the present invention according to another embodiment.

FIG. 4 is a schematic view showing an example of another filtering device 200 of the present invention in which seven modules M are mounted.
Similarly to the above, the constituent materials of the housing are all JIS standard hard polyvinyl chloride pipes and their joints.

Seven fixed type filtration modules M each having a total length of 75 cm shown in FIG. 1 are mounted through holes 226 provided in a partition plate 214 partitioning the filtration chamber 211 and the filtrate chamber 212 via an O-ring. . The partition plate 214 is also provided with a bubble discharging mechanism 224 and a bubble outlet 225.

The main pipe 216 of the filtration chamber 211 is a hard polyvinyl chloride pipe for water supply having a JIS standard nominal diameter of 300 A, and flange joints 221 are connected to both ends of the main pipe 216. A hole 227 for introducing the liquid to be treated is provided at the lower end of the pipe. The lower end of the module M is mounted by disposing the fixing plate 215 having the same. A plurality of introduction holes 228 for the liquid to be treated are also provided between the holes 227.

The fixed plate 215 also has a bubble supply mechanism 222 and a gas inlet 223. The bubble supply mechanism 222 is made of a metal pipe, and each module M has a bubble discharge hole having a diameter of 0.5 to 2 mm substantially on the center line.

The filtrate chamber 212 is constituted by a space surrounded by a partition plate 214, a spacer flange 229, and a flange 217 formed by welding a 100 A pipe for forming the filtrate passage 212. The outlet of the filtrate passage 212 is a flange joint 219. The introduction passage 213 for the liquid to be treated also has a fixed plate 21 like the outlet passage for the filtrate.
5, spacer flange 230 and filtrate passage 213
21 welded 100A pipe for forming
It is composed of a space surrounded by 8. The inlet of the liquid to be treated is a flange joint 220.

The module M is at least 300 KPa
Since it has the strength to withstand the backwashing pressure, the upper and lower parts are fixed by the partition plate 214 and the fixing plate 215, so that the module M can be backwashed without dropping from the hole 226 of the partition plate 214.

When the module M is taken out, the bolts for fixing the main pipe flange 221, the partition plate flange 214, the spacer flange 229 and the flange 217 forming the filtrate passage are removed. Next, the fixing bolt of the outlet flange 219 is removed to remove the filtrate chamber and the filtration passage member.
The module M mounted on the partition plate 214 is pulled out from the main pipe 216, and the module is removed from the partition plate.

When mounting the modules M, first, the modules M are inserted into the main pipe 216 having an open upper part, and the lower ends of the modules M are housed in the predetermined holes 227 of the fixing plate 215 one by one. Next, after aligning the filtrate outlet 7 (see FIG. 1) of each module with each hole 226 of the partition plate 214,
Push in the partition plate 214. Again, the spacer flange 229 and the flange 217 are overlapped and fixed with bolts, and the outlet flange 219 is also fixed with bolts.

Example of use of the filtration device of the present invention according to another embodiment

A filtration system similar to that shown in FIG. 3 was prepared using seven of the same module M, and the n-hexane extract was 1 pp.
m or less, electric conductivity of about 400 μS / cm, turbidity of about 2, particles number of 0.45 μm or more about 50,000 / c
m ³ , COD, TOC are about 4 and 2 ppm, respectively, F
The activated sludge treated water having an I (fouling index: index of clogging) value of about 20 was filtered.

The air bubbling after the back washing with the filtrate was carried out for 30 minutes at a flow rate of 100 L / min for 30 NL / mi.
The activated sludge treated water was continuously filtered for 3 weeks while repeating the cycle of discharging the washing liquid for 5 minutes at n.

During this period, the initial filtration pressure was about 30 KPa, but gradually increased to 100 KPa after 3 weeks. The electrical conductivity of the filtrate, n-hexane extract,
COD and TOC were almost the same as the stock solution,
The number of fine particles in the filtrate was 200 particles / cm ³ or less, and the FI value was about 3. The lowered filtration performance was restored to almost the initial performance by washing the hollow fiber membrane with acid and alkali.

(Comparative Example 1) As shown in FIG. 5, instead of the perforated cylinder 2 of FIG.
A cylinder 302 having four holes 304 was used, and instead of the partition plate 14 of FIG. 2, the cylinder 302 was passed through the hole 326, a gasket 306 was overlaid, and the module 300 was fixed to the partition plate 314 with bolts.

The lower end of the module 300 is the fixing plate 1 of FIG.
It was set apart from 5. Others were the same as those in FIG. 2, and a filtration device was prepared. Example 1 using this filtration device
A filtration test was conducted in the same manner as in, but similar results were obtained, and there was no difference from the standard type.

[0044]

As described above, according to the present invention, it is possible to provide an economical hollow fiber membrane filtration device using a fixed-type hollow fiber membrane module having a filtration capacity recovery mechanism suitable for medium-scale filtration.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional view showing a regular type filtration module using a hollow fiber membrane.

FIG. 2 is a partially omitted cross-sectional view showing a specific example of the hollow fiber membrane filtration device of the present invention.

FIG. 3 is a simplified piping diagram showing a usage example of the hollow fiber membrane filtration device of the present invention.

FIG. 4 is a partially omitted cross-sectional view showing another specific example of the hollow fiber membrane filtration device of the present invention.

FIG. 5 is an abbreviated cross-sectional view showing a part of a filtering device that is prepared for comparison with the filtering device of the present invention and uses one suspension module similar to the conventional one.

[Explanation of symbols]

 M Hollow fiber membrane module 1 Hollow fiber membrane 2 Cylinder 3 Focusing / fixing part 4 Header 5 Hole 6 Hole 7 Outlet 8 O-ring 10 Filtration device 11 Filtration chamber 12 Filtration liquid chamber 13 Introducing passage for liquid to be treated 14 Partition plate 15 Fixed plate 16 Main pipe 17, 18, 19, 20 Flange joint 21 Main pipe flange 22 Bubble supply mechanism 23 Gas inlet 24 Bubble discharge mechanism 25 Bubble outlet 26, 27 hole 28 Introduction hole 100 Tank 101 Stirrer 102 Pump 103 Cylinder 104 Backwash liquid Tank 105 Cleaning fluid tank 106 Filtrate flow meter 107 Gas flow meter 109,110 Pressure gauge 111 Valve 112 Supply valve 113 Discharge valve 114,115 Pressurized air valve 116 Bubble outlet valve 117 Valve 200 Filtration device 211 Filtration Chamber 212 Filtrate chamber 213 Liquid to be treated Introduction passage 214 partition plate 215 fixed plate 216 main pipe 217, 218, 219, 220 flange joint 221 main pipe flange 222 bubble supply mechanism 223 gas inlet 224 bubble discharge mechanism 225 bubble outlet 226, 227 hole 228 introduction hole 229, 230 Spacer Flange 300 Module 302 Cylindrical 303 Focusing Fixing Part 304 Hole 306 Gasket 314 Partition Plate 326 Hole

Claims (5)

[Claims] 1. An external pressure type filtration device for filtering from the outside to the inside of a hollow fiber membrane, comprising a lower filtration chamber having an inlet for a liquid to be treated, a bubble supply mechanism and a bubble discharge mechanism, and a filtrate outlet. On the partition plate that separates the upper filtrate chamber from the filter chamber, the filtrate outlet side of the hollow fiber membrane module, which is a fixed type cartridge filter, is detachably attached from the filter chamber side through an O-ring. And attach the other end of the module to the fixing plate having a hole communicating with the inlet of the liquid to be treated and the air supply mechanism from the filtration chamber side in a detachable manner, and fix the hollow fiber membrane module at both ends. The hollow fiber membrane filtration device is characterized in that the hollow fiber membrane module is not detached from both mounting portions even when backwashing. 2. A main member other than the hollow fiber membrane module is J
The hollow fiber membrane filtration device according to claim 1, comprising IS standard pipes and joints compatible with these pipes. 3. The JIS standard pipe and the fittings compatible with these pipes are made of hard polyvinyl chloride.
The hollow fiber membrane filtration device described. 4. The hollow fiber membrane filtering device according to claim 1, wherein the partition plate is provided with a mechanism for discharging bubbles. 5. The hollow fiber membrane filtration device according to claim 1, 2 or 3, wherein a bubble supply mechanism is provided on the fixed plate.