JPS622841B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hollow fiber assembly using hollow fibers whose membrane walls are selectively permeable to fluids.

Operations in which membrane separation devices are used include gas separation, liquid permeation, ultrafiltration, and reverse osmosis.
Specific examples of applications include desalination of seawater, desalination of brine, purification of various wastewater, purification of proteins, concentration of fruit juice, and oil/water separation.

Conventionally, there have been many proposals for membrane separation devices using hollow fibers, but a typical example is a hollow fiber assembly in which a large number of hollow fibers are arranged in layers around the heart tube. In this case, the heart tube is known to be a cylindrical tube with many small holes in its wall, and representative examples are shown in Japanese Patent Publication No. 47-11696, Japanese Patent Publication No. 47-22387, etc. .

In this way, the heart tube placed in the center of the hollow fiber layer serves as a supply channel for the fluid to be treated that has been supplied to the membrane separation device, or as a discharge channel for the fluid to be treated that has already passed through the hollow fibers. In particular, care must be taken to ensure that the flow of the fluid to be treated is uniform in the hollow fiber layer. Conventionally, a hollow tube with many small holes has been proposed as the heart tube, but the hollow fiber layer near the unperforated part of the heart tube becomes a dead space, and there is insufficient contact with the fluid to be treated, so that permeation is difficult. The disadvantage is that the flow rate and separation efficiency are reduced. To reduce the dead space, increase the number of holes, but in order to obtain a uniformly distributed flow of the fluid to be treated, it is necessary to keep the pressure loss of the fluid passing through the holes above a certain limit, so the diameter should be increased. This method has the disadvantage that many small holes need to be made, making the heart tube extremely complicated to manufacture. Also, a porous tube made of sintered metal or the like is known as a core tube, but this method has the drawbacks of large pressure loss and clogging.

The present inventors have found that the above-mentioned drawbacks can be solved by using a pillar having substantially continuous protrusions in the length direction instead of the conventional heart tube as a support for the hollow fiber layer. This is the heading that led to the present invention.

That is, in the present invention, a fiber layer made of permselective hollow fibers spirally wound around a column having substantially continuous protrusions in the length direction is arranged in the outer cylinder,
A fluid passage is formed between the concave portion of the column and the fiber layer, and both ends of the fiber layer accommodate a hollow fiber assembly composed of resin walls, and the resin wall is connected to the fiber layer through an annular member. The membrane separator is supported by end plates, the end plate has a fluid outlet and is supported on the outer cylinder by a snap spring, and one end plate has a fluid inlet and outlet and is supported by the outer cylinder via the snap spring. be.

In the present invention, a column having projections that are substantially continuous in the length direction means that when hollow fibers are arranged around the column, there is a gap between the concave part of the column and the fiber layer over the length of the column. A continuous fluid passage is formed in the longitudinal direction. It is preferable that the protrusions of the column are continuous in the length direction, but the fibers may be arranged around the column and may be discontinuous to the extent that the fibers do not enter the recesses of the column. Further, the cross section of the column has at least three protrusions. In addition, the column itself may be hollow, and many small holes may be provided on the side of the column.
The hollow portion of the column may communicate with a fluid passage formed between the recess of the column and the fibrous layer through a small hole.

Such a column having a substantially continuous protrusion in the longitudinal direction generally has a cross-sectional diameter of 10 to 100 mm, the height of the protrusion in the cross section (radial length) is generally 4 to 40 mm, and the column has a diameter of 10 to 100 mm. length is
100-5000mm is suitable. The material of the column is generally synthetic resin, but it may also be made of metal or inorganic material. Examples of the synthetic resin include polyethylene, polypropylene, polyvinyl chloride, nylon 6, nylon 66, nylon 12, polyethylene terephthalate, and polycarbonate.

The hollow fibers used in the present invention have an outer diameter of 10 to 1000 microns and a hollow ratio of 3 to 80%, and are not particularly limited as long as their membrane walls have selective permeability to fluids. The membrane walls of these hollow fibers may be homogeneous, microporous, or anisotropic.

In the present invention, when forming a fiber layer by arranging hollow fibers around a column, the fiber layer is supported at the tips of the protrusions of the column, and the hollow fibers are arranged so as not to enter the recesses of the column. It is necessary to.
For example, when hollow fibers are repeatedly wound spirally around a column, a fiber layer supported by the tips of the protrusions is formed around the column, leaving a space free of hollow fibers in the recess. Further, in the hollow fiber assembly thus obtained, it is preferable to arrange the hollow fibers as densely as possible to reduce the gaps between the fibers. The closely packed fibrous layer creates a pressure differential with the fluid passageway to allow for even flow of the fluid to be treated throughout the length of the assembly. However, it is not preferable to arrange the hollow fibers too closely because it tends to cause concentration polarization in the fluid to be treated. It is desirable that the actual proportion of the constitution of the hollow fibers to the apparent volume of the hollow fiber layer is 65% or less.

In the present invention, the resin constituting the resin wall is preferably a fluid that is fluid before curing and becomes a hard solid upon curing. Typical examples thereof include epoxy resin, silicone resin, and polyurethane resin. be able to. In the hollow fiber assembly of the present invention, the resin wall is generally provided perpendicularly to the axis at one end or both ends of the hollow fiber assembly, but it may also be provided on the side surface of the cylindrical portion of the hollow fiber layer. Each hollow fiber passes through at least one of the resin walls and opens to the outside, and the space between the hollow fiber and the resin wall is sufficiently sealed against fluid.

Next, the present invention will be explained in more detail with reference to the drawings.

FIG. 1 shows a partially cutaway sectional view of a specific example of the hollow fiber assembly of the present invention, in which a fiber layer 2 is arranged around a column 1 having continuous protrusions in the length direction, A fluid passage 3 is formed between the recess of the column 1 and the fiber layer, and both ends of the fiber layer are hollow fiber assemblies composed of resin walls 4 and 5.

One end of the fluid flow path 3 communicates with a fluid inlet/outlet of the membrane separation device via a pipe 6, and the other end is closed by a resin wall 4. fiber layer 2
The hollow fibers constituting the resin wall 5 have a U-shape.
It is folded back inside and both ends thereof penetrate through the resin wall 4 and open to the outer opening surface 7.

FIG. 2 shows a sectional view taken along the - line in FIG. 1. In this case, the column 1 has six protrusions, and the hollow fibers are placed in contact with the tips of the protrusions and not in contact with the recesses, so that a continuous fluid exists in the length direction between the column and the fiber layer 2. A passage 3 is formed.

FIG. 3 is an enlarged perspective view of the column 1 in the hollow fiber assembly of FIG. 1.

FIGS. 4, 5, 6, 7, 8, 9, and 10 show cross-sectional views of other specific examples of the columnar body of the present invention. In either case, a fluid passage is formed between the recess of the column and the fiber layer. In particular, Fig. 9 has a fluid passage in the center, and the fluid passage in the center consists of a fluid passage formed between the concave part of the column and the fiber layer, and a large number of small holes provided on the side of the column. This figure shows columns with a communicating structure.

FIG. 11 shows a sectional view of a specific example of a membrane separation device in which the hollow fiber assembly shown in FIG. 1 is housed in a container.

The resin wall 4 is supported by an end plate 9 via an annular member 12, and the end plate 9 is provided with a fluid outlet 13 and supported by a cylinder 8 by a snap ring 14. One end plate 10
has a fluid inlet and outlet 11, 15 and a snap spring 1
It is supported by a cylinder 8 via 6.

Also, O-rings 17, 1 are used as a fluid sealing mechanism.
8 and 19 are provided. To explain the flow of fluid when performing a reverse osmosis operation using such a membrane separation device, first, the fluid to be treated that is supplied to the fluid inlet/outlet 11 enters the fluid passage 3 through the pipe 6 and flows into the fiber layer 2. . While the fluid to be treated passes through the fiber layer 2, a portion thereof permeates into the hollow fibers and is discharged from the fluid outlet 13 through the flow path within the hollow fibers.
On the other hand, the fluid to be treated that has passed through the fiber layer 2 without permeating into the hollow fibers is discharged from the fluid inlet/outlet 15 through the annular channel between the fiber layer 2 and the cylinder 8.

Since the fluid passages of the hollow fiber assembly of the present invention are formed in the fiber layer itself, there is no dead space near the contact area between the core tube and the hollow fibers, unlike when a porous core tube is used, and the liquid treatment fluid can flow throughout the fiber layer. It flows uniformly over the entire area, and no concentration polarization occurs. As a result, when the hollow fiber assembly of the present invention is used, it is possible to provide a membrane separation device with a larger permeation flow rate and higher separation efficiency than conventional ones. In addition, when the fiber density of the hollow fiber layer is increased, a fluid pressure difference occurs between the fluid passage formed jointly by the column and the fiber layer and the fiber layer, so that the fiber density is increased throughout the length of the hollow fiber assembly. The flow of fluid inside the hollow fiber layer can be made uniform, and the fluid to be treated can be uniformly brought into contact with the hollow fibers throughout the layer. In addition, by changing the design of the branching part of the column, the volume of the flow path made up of the branching part and the fiber layer can be adjusted, and the flow rate of the fluid to be treated in the flow path can be freely selected. There are advantages. Furthermore, the columnar body having a branched cross section according to the present invention can be mass-produced in a few steps using a drawing method or the like, and there is no need for long manufacturing steps such as those for perforated tubes or sintered metal tubes.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway sectional view of the hollow fiber assembly of the present invention, FIG. 2 is a sectional view taken along the - line in FIG. 1, FIG. 3 is a perspective view of the column shown in FIG. ~10
The figure is a cross-sectional view of the columnar body of the present invention, and FIG. 11 is a cross-sectional view of a membrane separation device containing the hollow fiber assembly of FIG. 1.

Claims (1)

[Claims] 1 A fibrous layer formed by winding permselective hollow fibers in a helical manner around a columnar body having substantially continuous protrusions in the length direction is disposed in the outer cylinder, and a concave portion of the columnar body and the fiber layer A fluid passage is formed between the fiber layer, and both ends of the fiber layer accommodate a hollow fiber assembly composed of resin walls, and the resin wall is supported by the end plate via an annular member, and the end plate A membrane separation device is provided with a fluid outlet and supported on the outer cylinder by a snap spring, and one end plate is provided with a fluid inlet and outlet and supported on the outer cylinder via the snap spring.