JPH0366929B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a cylindrical semipermeable membrane module with improved permeation performance.

For more details, see semi-permeable membranes with improved performance used in reverse osmosis and ultrafiltration methods using semi-permeable membranes, which are being put into practical use in the food and pharmaceutical industries as liquid concentration, separation and purification methods. Regarding membrane modules.

It goes without saying that the key factors that determine the performance of reverse osmosis and ultrafiltration devices that use semipermeable membranes are the performance of the semipermeable membrane and the performance of the module that is processed and molded to make it easy to handle. stomach.

There are various types of semipermeable membrane modules, but it is well known that the cylindrical semipermeable membrane module described above is suitable for treating liquids containing suspended substances and liquids with high viscosity. This is where I am.

(Prior art) By the way, this cylindrical semipermeable membrane module has a lower membrane packing density per unit volume than other types of modules, so in order to increase the processing capacity of equipment, the performance per module, especially Although it is essential to improve the transmission performance, the fact is that there is little room for improvement because the structure is relatively simple.

For example, it has been proposed to increase the number of small holes drilled in the pressure-resistant support tube, to increase the diameter of the holes, or to form a plurality of small grooves in a line inside the pressure-resistant support tube.

(Disadvantages of Prior Art) That is, the methods for increasing the amount of permeate as described above each have the following disadvantages.

First, the method of increasing the number of small holes drilled in the pressure-resistant support tube increases the processing cost considerably, but the amount of permeate increases only slightly, and in the case of the ultrafiltration method, plastic pipes are generally used. Since it is often used as a pressure-resistant support tube, there is a problem in terms of pressure-resistant strength.

The method of increasing the diameter of the small pores also results in a small increase in the amount of permeated liquid, and there is a problem in terms of pressure resistance of the semipermeable membrane with a support in the small pore area.

Additionally, creating multiple small grooves on the inner surface of the pipe is very effective in increasing the amount of permeate;
Similar to the method of increasing the number of small holes, there is a problem in terms of pressure resistance, particularly in the case of the ultra-pass method, which uses plastic pipes as pressure-resistant tubes.

(Configuration of the present invention) Next, the configuration of the present invention will be explained in detail using the drawings.

Figure 1 shows a cross-sectional view of an ordinary cylindrical semipermeable membrane module with no conventional modifications, and 1-1 is made of stainless steel with small holes perforated at regular intervals in the length direction. Alternatively, it is a pressure-resistant support tube made of plastic, usually 1 to 5 m in length and 10 to 50 mm in inner diameter. Reference numeral 2-2 denotes a support for a semipermeable membrane with a support having an outer diameter that is in close contact with the inner surface of the pressure-resistant support tube 1-1, and is usually made of woven fabric or non-woven fabric.

3-3 is a cylindrical semipermeable membrane that is cast onto the support 2-2 and is usually integrated therein, and 4-4' is perforated at regular intervals in the length direction of the pressure-resistant support tube 1-1. A small hole that serves as a passage for the permeate, usually with a pore diameter of 0.5 to 1 mm.
φ, and the perforation pitches are 50 to 100 mm apart.

On the other hand, FIG. 2 is a cross section of the cylindrical semipermeable membrane module of the present invention, where 5-5 is a pressure-resistant support tube, 6-6
is a semipermeable membrane support with a support, 7-7 is a support 6
- 6 is a cylindrical semipermeable membrane cast, 8-8' is a small hole drilled in the pressure-resistant support tube 5-5, and 9-9 is a cylindrical semi-permeable membrane support 6-6 and pressure-resistant support. A filament-like object, each of which is individually continuous and is generally parallel to the length of the pressure-resistant support tube that is slid between the tube 5-5 and is not interconnected, and is usually a yarn made of synthetic fiber. Alternatively, the thickness of spun yarn is 40μ to 200μ, the denier is about 20 to 400, and the count is about 250 to 15. In the case of a tube membrane with an inner diameter of 14 mm, the appropriate number of yarns or spun threads to be slipped is from several to more than ten.

Reference numeral 10-10 is a space formed by the filamentous material 9-9 between the cylindrical semipermeable membrane support 6-6 and the pressure-resistant support tube 5-5 and serving as a passage for the permeate. Third
The figure is an enlarged view of the vicinity of 9-9 in FIG.

(Effects of the Invention) In the cylindrical semipermeable membrane having a cross-sectional structure as shown in FIG. 1, the permeated liquid that has permeated the semipermeable membrane 3-3 is collected in the small holes 4-4' and taken out to the outside. At this time, the permeate near the small holes 4-4' flows with almost no flow resistance, but the permeate that permeates through the semipermeable membrane in the area far from the small holes 4-4' permeates inside the support. As a result, the flow resistance increases and sufficient permeation performance cannot be ensured.

On the other hand, in the case of the cylindrical membrane according to the present invention as shown in FIG.
Since 9 serves as a passage for the liquid that has permeated through the semi-permeable membrane, the permeated liquid can flow easily and the permeation performance is significantly improved.

Next, the effects of the present invention will be explained based on Examples and Comparative Examples.

Example Pressure-resistant support pipe: Nippon Bokan Co., Ltd. 17.5φ/14.5φ, 2250
Hard PVC semi-permeable membrane: Polysulfone ultra-permeable membrane manufactured by Daicel Chemical Co., Ltd. (see JP-A-57-94309) Small holes: 90 holes in total, 45 perforated on opposite sides of the pipe at 50 mm intervals Hole diameter: 1 mmφ and a half Yarn to be slipped between the membrane support and the pressure-resistant support tube: Made of polyester, 110 denier Number of yarns: 8 equally spaced in the circumferential direction Performance measurement conditions: Water flow rate: 1 m ³ /hour Water temperature: 25°C Operating pressure: 3 kg /cm ²・G Permeation performance water amount 22m ³ /m ²・day Comparative example Except for not using 110 denier polyester yarn, everything was carried out in the same manner as in the example, and a permeation water amount of 12m ³ /m ²・day was obtained. Ta.

Comparing the results obtained in this example with the results obtained in the comparative example, it can be seen that the transmission performance is increased by about 80%, indicating that the present invention is effective.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view of a conventional cylindrical semipermeable membrane without any modifications, Fig. 2 is a cross-sectional view of a cylindrical semipermeable membrane of the present invention, and Fig. 3 is a filamentous object shown in Fig. 2. It is an enlarged view of the vicinity.

Claims (1)

[Claims] 1 In a cylindrical semipermeable membrane module in which a cylindrical semipermeable membrane with a support is inserted into a pressure-resistant support tube and both ends are sealed, the longitudinal direction between the outer periphery of the cylindrical semipermeable membrane with a support and the pressure-resistant support tube roughly parallel to
A cylindrical semipermeable membrane module characterized in that it has a structure in which each of a plurality of unconnected threads is individually inserted with a continuous thread-like object.