JPS61181503A - Apparatus for filtering solution - Google Patents

Abstract

PURPOSE:To eliminate or reduce the concn. polarization on the surface of a membrane by covering both surfaces of a carrier wherein a soln. path is provided with a semipermeable membrane, and inserting a rotating shaft to be used as a liq. discharge port provided with many filter plates into the central part of a vessel. CONSTITUTION:A rotating shaft 22 furnished with many filter plates 23 is vertically provided in a vessel 21. The filter plate 23 is obtained by covering both surfaces of a porous membrane carrier with a semipermeable membrane to seal the carrier, a path through which a permeated liq. is passed is furnished at the inside, and the liq. is collected into the rotating shaft 22 from a hole at the central part. A permeated liq. outlet 24 for discharging a permeated liq. 4 is provided to the lower part of the rotating shaft 22. The rotating shaft 22 is rotated by a motor 29, and the number of revolutions is regulated in accordance with the quality of untreated liq. 3. Filtration is carried out under pressure or under reduced pressure through the rotating shaft 22.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a solution filtration device using a semipermeable membrane using pressure as a driving force, and particularly to a solution filtration device that efficiently performs microfiltration and ultrafiltration operations. be.

[Prior art]

In recent years, with the development of culture, the use of water and energy has increased year by year, and it has become necessary to produce fresh water from seawater, purify and reuse used wastewater, and remove valuable and harmful substances in solutions in various processes. Many efforts have been made to efficiently concentrate and separate substances using energy-saving processes as much as possible.

Various separation or removal methods such as evaporation, adsorption, and activated sludge methods are used for this process, and membrane separation is also an effective separation method.

The membrane module devices used in this membrane separation process are mainly hollow fiber tubular type, spiral type, and pressure plate type (
The outer shape of the hollow fiber type is as shown in Figure 5, and the inner diameter is 0.8 to 1.4.
A large number of hollow fibers at position fi are fixed with hollow fiber bundle fixed ends 1 at both ends, a hollow fiber membrane 2 is installed inside the drum, a stock solution 3 is introduced, a filtrate 4 is taken out from the upper part, and a concentrated solution 5 is formed. is taken out from the opposite side.

Therefore, if the concentration of the stock solution 3 is high or if large particles are mixed in, there will be a problem that the stock solution flow path will be easily blocked.On the other hand, since the stock solution 3 is supplied at a high flow rate through a narrow gap, there will be no pressure loss. big.

In addition, the tubular module structure shown in Fig. 6 usually has a semipermeable membrane 6 attached to the inside of a porous tubular support with an inner diameter of l to 2.5 am. The tubes are connected in series, and the stock solution 3 is introduced from one of the tubes, the concentrated solution 5 is taken out from the other, and the permeated water 7 that has passed through the semipermeable membrane 6 is taken out.

In this case, since the stock solution 3 is filtered through the inside of the tube as described above at a high flow rate, this module has the highest energy consumption per unit filtration amount and the lowest membrane packing density per unit volume.

Next, as shown in FIG. 7, in a pressure plate type (plate and frame type) module consisting of a plate 8, a stop disk 9, a neck ring 1o, a membrane 11, etc., the stock solution 3 flows through the gap between the membranes 11 at a high flow rate. The flow turns sharply at the end and is fed into the gap of the next membrane 11.

Therefore, there is a problem that the pressure difference between the inlet of the stock solution 3 and the outlet of the permeated water 7 of the module is very large, and the energy required for filtration is large, and it is impossible to physically clean the membrane 11.

Furthermore, in the 4-spiral type module shown in Fig. 8, the stock solution 3 flows through the gap between the supports of the mesh 12 sandwiched between the membranes, filtration occurs, and the filtrate 4 is taken out, and the support and the membrane are in contact with each other. This part does not function as a semipermeable membrane.

In addition, in such areas, solutes and suspended matter may deposit during filtration, grow, and block the flow path, and fluids with high viscosity, highly concentrated solutions, or solutions with suspended matter may Processing problems may occur.

In addition, when filtration is performed using a semipermeable membrane, the concentration of solutes on the membrane surface increases as the solvent is filtered, which creates a large filtration resistance and causes further deposits and adhesion on the membrane surface. This may cause deterioration of membrane performance.

To reduce this phenomenon, the stock solution is sent to the module at a high flow rate, stirred vigorously, and washed with a sponge ball.

However, when using the above module, the hold-up amount of the module is large relative to the membrane area, so filtration separation cannot be achieved just by passing the stock solution once. A predetermined purpose is achieved by arranging the liquid in several stages, and in such a method, there is a large loss of kinetic energy of the raw liquid due to bending of the connecting pipe, etc.

Therefore, the result is that several times to several tens of times more energy is required than the theoretical separation energy required for filtration.

Furthermore, in separation operations using membranes, energy costs account for a very large proportion of the total treatment cost; for example, when concentrating lignin in pulp bleaching waste 10 times by ultrafiltration, it costs 2,000 to 4,000 rrr/ There is a problem in that on a daily permeated water treatment scale, energy costs account for 70 to 80% of the total treatment cost using tubular and pressure plate type modules.

[Purpose of the invention]

Therefore, the present invention was made to solve the problems by considering the current state of the conventional filtration modules mentioned above. The purpose is to provide a solution filtration device that has no energy loss due to resistance and no pressure loss within the module, maintains high module performance, and also does not require high pressure resistance and has no pressure loss inside the filtration tank. The purpose of this invention is to provide a solution filtration device that can be easily equipped with a membrane set.

[Structure of the invention]

That is, in the solution filtration device of the present invention, both sides of a membrane support having a solution passage are covered with semipermeable membranes, and a plurality of filter plates each having a hole in the center are connected to a rotating shaft that serves as a filtrate outlet. It is constructed by installing a set of membranes stacked at regular intervals through the above-mentioned holes in the tank, and performing filtration under pressure or reduced pressure while rotating the membrane set.

〔Example〕

A solution filtration device according to an embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic vertical cross-sectional view of Embodiment 1, and a large number of filter plates 23 are installed in a tank 21 in the figure. A rotating shaft 22 is provided vertically.

These filter plates 23 are made by covering and sealing both sides of a porous membrane support with a semipermeable membrane, and have a passage through which the solution that has permeated the semipermeable membrane passes, and a hole provided in the center. The liquid is collected in the rotating shaft 22.

That is, a large number of filter plates 23 having holes in the center are used to filter the filtrate 4.
A set of membranes is formed by stacking the membranes at regular intervals on a rotary shaft 22 having a filtrate outlet 24 at the bottom, which discharges the filtrate, and is installed in the tank 21.

When performing membrane filtration under pressure using such a membrane set, the tank 21 must be kept airtight from the outside air, so the rotating shaft 22 must be airtight at the top and bottom using a mechanism such as a mechanical seal 25. On the other hand, the membrane retains its properties in tank 21.
When the tank 21 is installed in a deep lower part of the tank and filtration is performed using its hydrostatic pressure, or when the filtration is performed under reduced pressure via the rotating shaft 22, airtightness is not required between the tank 21 and the rotating shaft 22.

Here, 26 is a pulp into which gas is introduced or discharged to pressurize the inside of the tank 21, if necessary.

Further, 27 is a supply port for the stock solution 3, 28 is a discharge port for the concentrated solution 5, and 29 is a motor for rotating the filter plate 23, whose rotation speed depends on the properties of the stock solution 3, the purpose of filtration, etc. It will be adjusted accordingly.

The rotating shaft 22 can be installed vertically as shown in FIG. 1, horizontally as in the second embodiment shown in FIG. A large number of membrane sets may be installed in the tank 21 with the rotating shaft 22 as the center.

Furthermore, more effective filtration performance can be obtained by alternately rotating the filter in different directions as shown in FIG.

As shown in FIG. 4, the membrane set in which the above-mentioned filter plates 23 are laminated is made up of a membrane support 31 such as a metal or plastic porous body or a plate, and a material that serves as a passage for the heavy ring solution is superimposed on both sides of the membrane support 31. A plurality of donut-shaped disks with holes 30 into which the rotating shaft 22 with a large number of water permeable holes 34 can be inserted are inserted into the center of the transparent membrane, which is sealed with an adhesive or a seal. 32 and spacers 33 to stack them at regular intervals and tighten both ends to maintain airtightness, and this will be referred to as a membrane set here.

Since this membrane set is attached to the rotating shaft 22, the membrane set is used as a cassette, and the semipermeable membrane can be easily replaced and cleaned. The membrane support 31 is most commonly a disk, but is not limited to a rectangular, square, polygonal, or elliptical shape.

[Effects of the Invention] As mentioned above, in the conventional filtration of commercially available modules, normally the stock solution was passed vigorously over the fixed membrane surface to permeate the membrane, but in the solution filtration device of the present invention, only the processed stock solution is passed through the membrane. is supplied into the module tank, and the concentration polarization on the membrane surface that accompanies filtration can be eliminated or reduced by rotating the laminated membrane force set.

Therefore, in the device of the present invention, unlike conventional commercially available module systems, there is almost no energy loss due to flow paths due to intense flow of stock solution or resistance in the module wall, so not only energy costs are reduced, but also energy loss inside the module is reduced. Since the pressure loss at -IJ<ft is low, there is an effect that high module performance can be maintained with low pressure operation, and moreover, high pressure resistance is not required for the device.

In addition, the membrane packing density per unit volume ranges from 100 to 400 r.
It has a sufficiently large membrane area and processing capacity at rf/rrr,
A further advantage is that the membrane centrifuge can be easily installed in the filtration tank and maintenance is simple.

Note that the apparatus of the present invention is an extremely effective apparatus particularly for efficiently carrying out microfiltration and ultrafiltration operations.

[Brief explanation of drawings]

FIG. 1 is a schematic vertical sectional view of a solution filtration device in Example 1 of the present invention, FIG. 2 is a schematic side sectional view of the device in Example 2, and FIG. 3 is a schematic plan view of the device in Example 3. FIG. 4 is a schematic side sectional view of an enlarged main part of FIG. 1, and FIGS. 5, 6, 7, and 8 are sectional views of different conventional solution filtration apparatuses. 3... Stock solution, 4... Filtrate, 21... Tank, 22...
... Rotating shaft, 23... Filter plate 24... Filtrate outlet, 26... Pulp, 29... Motor, 30... Hole, 31... Membrane support. Patent applicant: Director of the Agency of Industrial Science and Technology Tatsu Todoroki Figure 3

Claims (1)

[Claims] Covering both sides of a membrane support having a solution passage with a semipermeable membrane,
A plurality of filter plates with holes in the center are inserted through the rotating shaft that serves as the filtrate outlet, and a set of membranes stacked at regular intervals is installed in the tank and rotated. A solution filtration device characterized by performing filtration under increased pressure or reduced pressure.