JPS6331243B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to the construction of an assembly using hollow fibers whose membrane walls are selectively permeable to fluids. The scope of application of membrane separation equipment includes gas separation, liquid permeation, dialysis, ultrafiltration, reverse osmosis, etc.
Specific examples of applications include desalination of seawater, desalination of brine, purification of various wastewater, purification of proteins, concentration of fruit juice, oil/water separation, and hemodialysis. There have been many proposals for membrane separation devices using permselective hollow fibers, but the usual ones are hollow fiber assemblies in which many hollow fibers are arranged in layers around a single core tube. A typical structure is one housed in a container. In this case, it is known that the core tube is a cylindrical tube with many holes drilled in the tube wall, and representative examples are shown in Japanese Patent Publication No. 11696/1982 and Japanese Patent Application Laid-open No. 22387/1983. There is. A continuous core tube with such a large number of small holes is said to have a structure suitable for uniformly dispersing the fluid to be processed supplied to the membrane separation device in the hollow fiber layer, but in reality, the following is true. There are drawbacks such as. That is, (1) a part of the hollow fiber layer in contact with the non-perforated part of the core tube becomes a dead space, and since the fluid to be treated stays in that part, there is insufficient contact with the new fluid to be treated; Permeate flow rate and separation efficiency decrease. Additionally, when fluid is supplied from the core tube to the hollow fiber layer, this dead space obstructs the uniform radial flow of the fluid, creating polarized flow and concentration polarization, which significantly reduces permeation performance and separation efficiency. . (2) In order to uniformly disperse and extrude the fluid to be treated through the small holes in the core tube into the hollow fiber layer, a considerable amount of pressure is required, and the pressure loss at this time is large. (3) Small pores in the core tube are likely to become clogged by small amounts of solid particles in the fluid to be treated, and once clogged, the dead space will further expand, further reducing separation efficiency. (4) When the fluid to be treated is forced out from the small holes in the core tube to the hollow fiber layer under high pressure, the hollow fiber layer expands due to the flow resistance of the fluid, and tension is generated in each hollow fiber. Such tension acts on the resin walls to which the fibers are fixed, reducing the distance between the resin walls of the assembly, and thus the effective length of the hollow fiber assembly. In this case, if the strength of the single core tube used is low, the assembly itself will undergo large shrinkage, ultimately resulting in a decrease in separation performance. For example, if the assembly shrinks, rough hollow fibers will occur locally in the hollow fiber layer, causing problems such as uneven flow of the fluid to be treated and concentration polarization, or to the core pipe of the assembly. The distance between the conduit that supplies the fluid to be treated and the assembly becomes large, and the connection between the conduit and the end plate comes off, causing operational inconveniences in which the fluid to be treated does not flow into the core pipe. However, the separation efficiency and permeation performance of the hollow fiber assembly are significantly reduced. (5) On the other hand, in order to prevent performance deterioration due to assembly shrinkage as described in (4) above, it is possible to use a strong core pipe to prevent shrinkage, but in this case, the total pressure during water flow All work on hollow fibers,
The hollow fibers are partially stretched due to the fluid flow resistance, and some permanent deformation remains, which significantly reduces the separation efficiency and permeation performance of the hollow fiber assembly. (6) When forming the end of a hollow fiber cylindrical aggregate by impregnating and curing a fluid adhesive, close off some of the small holes in the core tube wall that are provided to uniformly disperse the fluid to be treated. Therefore, as mentioned above, this is one of the causes of a decrease in separation ability and permeation flow rate. The present invention improves the drawbacks of the conventional hollow fiber assembly having a continuous core tube as described above, and provides a hollow fiber assembly which has a large permeation flow rate and separation efficiency, and has good durability. Specifically, the present invention is a hollow fiber assembly in which permselective hollow fibers are arranged in a cylindrical shape, and the hollow fiber cylindrical layer is formed by intersectingly arranging hollow fibers having an open end. a hollow portion existing inside the cylindrical assembly of hollow fibers; a plurality of fitting cylindrical members located within the hollow portion and spaced apart from each other; and an open end portion of the hollow fibers. The hollow fibers are arranged so as to open on the outer surface of the resin wall (A) without any gaps between the fibers and the resin wall (A), and are arranged apart from the fitting cylinder member. The resin wall (A), the resin wall (B) at the other end of the assembly and fixing the end of the cylindrical assembly, and the interval between the two resin walls are regulated. This is a flexible permselective hollow fiber assembly composed of an elastic support member and a fluid conduit. The configuration of the permselective hollow fiber assembly of the present invention shown in the drawings will be described below. FIG. 1 is a partially cutaway side view showing an example of the assembly of the present invention;
Figure 2 is the left side of Figure 1, a front view showing the opening section;
FIG. 3 is a central vertical sectional view of FIG. 1, FIG. 4 is a central vertical sectional view showing an example of a membrane separation device equipped with the assembly shown in FIG. 1, and FIGS. 6 and 8 are longitudinal sectional views of a membrane separation device using the assembly shown in FIGS. 5 and 7, and FIG. 9 is a partially cutaway side view showing an example of the configuration. FIG. 10 is a partially enlarged cross-sectional view, FIG. 10 is a cross-sectional view taken along the cutting line X-X in FIG. 11th
FIG. 13 is an enlarged view of the main part of the figure, FIG. 13 is a sketch diagram explaining a partial configuration of FIG. 12, and FIG. 14 is a partial diagram showing a cross-shaped arrangement of hollow fibers. In Fig. 1, 1 is a hollow fiber cylindrical layer, and its arrangement is as shown in Fig. 14, in which tape-shaped hollow fiber bundles in which hollow fibers are arranged substantially parallel to each other and flat are intersected and laminated. has been done. Reference numeral 2 indicates a cavity formed inside the hollow fiber cylindrical layers intersectingly arranged, and 3 indicates a plurality of fitting cylindrical members spaced apart from each other. It is preferable that the fitting members be arranged at a distance of 1 to 3 cm from each other. 4 is a resin wall (A) in which hollow fibers are arranged so as to open to the outside of the resin wall (A) without any gaps (see Fig. 2, 4a), and are different from the fitting cylinder member 3. is seperated. It is desirable that the distance be 1 to 5 cm. A resin wall (B) 5 fixes the end of the cylindrical assembly, and a fluid supply conduit 8 passes through the center thereof. 6 is an elastic support member that regulates the distance between the resin walls (A) and (B). Reference numeral 7 denotes a flow screen made of a net-like cloth or the like which is coated on the outside of hollow fibers and has low resistance to passage of fluid. FIG. 4 shows an example of a membrane separation apparatus equipped with the hollow fiber assembly shown in FIG. 1, and arrows indicate an example of the flow of the fluid to be treated. In this figure 9 is the case housing the assembly, with permeate output 13 at one end.
The end plate 10 has an end plate 10 having an inlet and an outlet for a fluid to be treated at the other end. end plate 10,
11 are supported by C-rings 17, respectively, and O-rings are installed on the hollow fiber assembly, the end plate, and the supply conduit,
The supply fluid (black and white arrow), permeate fluid (white arrow), and concentrated fluid (black arrow) are separated so that they do not mix, and leakage of fluids to the outside of the device is prevented. In the embodiment shown in FIG. 5, 1 is a hollow fiber cylindrical layer arranged as shown in FIG. 14, 2 is a cavity existing inside the hollow fiber cylindrical layer, and 3 is a plurality of fittings. A protective net 18 made of a net-like fabric is disposed on the joint tube member. 4 is a resin wall (A) in which hollow fibers are arranged so as to open to the outer surface without any gaps between the fibers and the resin wall (A), and there is a hollow part in the center. 2 and is separated from the fitting cylinder member 3. 5 is a resin wall
(B) fixes the end of the cylindrical assembly. Reference numeral 6 designates an elastic support member that regulates the distance between the resin walls (A) and (B), and 7 designates a flow screen made of a net-like cloth or the like that has little resistance to passage of fluid. FIG. 6 shows an example of a membrane separation apparatus equipped with the hollow fiber assembly shown in FIG. 5, and arrows indicate an example of the flow of the fluid to be treated. In this figure, 9 is a case that accommodates two of the above assemblies. The supply connector 19 is set in the center hole of the resin wall (A) 4, and the pressure receiving water collection plate 12 and the permeated water connector 20 are fixed in the case with the end plate 10. The left and right sides are assembled in the same way, and the fluid to be treated is supplied from one supply connector 19 (left side), and the concentrated fluid (black arrow) is taken out from the other supply connector. The permeated fluid is taken out from the left and right permeated water connectors 20 (white arrows). The fluid to be treated is passed through the left assembly from the cavity 2 side and from the outer peripheral side of the right assembly to permeate and separate them. In the embodiment shown in FIG. 7, 1 is a hollow fiber cylindrical layer, 2 is a cavity, 3 is a fitting cylindrical member, and 18 is a protective net covering the fitting cylindrical member. 4 is a resin wall (A)
In the center there is a hole 8 for inserting a supply conduit leading to the cavity.
The hollow fibers are arranged so as to open to the outside of the resin wall (A), and are separated from the fitting cylinder member 3. In terms of separation performance, it is preferable that the distance is 1 to 5 cm. 5 fixes the end of the assembly with a resin wall (B) and has a hole in the center. 6 is the resin wall (A)
The elastic support member 7 that regulates the distance from (B) is a flow screen. FIG. 8 shows an example of a membrane separation apparatus equipped with the hollow fiber assembly shown in FIG. 7, and arrows indicate an example of the flow of the fluid to be treated. Also, Figure 9 is an enlarged cross-sectional view of the left side part of Figure 8, and these figures show case 9.
accommodates three of the above-mentioned assemblies, and the permeate fluid coming out of the resin wall (A) 4 is collected in the permeate water collection block 21, flows into the permeate water conduit 22 from the center thereof, and is guided to the end plate 10. . The supply fluid enters the housing case 9 from the end 10 and passes through a hole in a perforated support plate 27 provided in the center of the resin wall (B) 5 of the assembly and a permeate conduit 22.
The permeated liquid is introduced into the cavity of the hollow fiber assembly through the hollow fiber layer 1 and the flow screen 7 to reach the inner wall of the storage case 9, and then between the permeate water collection block 21 and the storage case. through the second
The resin wall (B) 5 of the hollow fiber assembly is reached. It then passes through the second assembly and then through the third assembly to the right end plate, again following the same path as described above, and is removed as a concentrated fluid. FIG. 10 is a cross-sectional view taken along section line X-X in FIG. . FIG. 11 is an example of a membrane separation apparatus equipped with the hollow fiber assembly shown in FIG. 7, and an example of the flow of the fluid to be treated is shown by arrows. In this figure, 9 is a case that accommodates four of the above assemblies. In addition, Figures 12 and 13 are enlarged cross-sections and sketches of the water collection area,
The permeate fluid coming out of the hollow fiber openings of the resin wall (A) 4 of the first hollow fiber assembly passes through the water collection part 12a of the pressure receiving water collection plate 12, passes through the passage in the connecting pipe part 23, and then passes through the permeate water conduit. 22 and is guided to the end plate. The permeate fluid coming out of the second hollow fiber assembly is directed to the water collecting section 1 on one side of the pressure receiving water collecting plate 12 which is shared with the first assembly.
2a, the water flows into the permeated water conduit 22 through the continuous hole of the connecting pipe portion 23, and is guided to the end plate. The permeate fluid exiting the third and fourth assemblies is also directed to the end plate along a similar path as the permeate fluid exiting the first and second assemblies. Further, the supply fluid enters from the end plate 10, is guided to the outer periphery of the first assembly, passes through the flow screen 7, the hollow fiber layer 1, and reaches the cavity, and is connected to the connecting pipe section provided at the center of the resin wall (A). 23 into the cavity of the second assembly. The fluid that has passed through the hollow fiber layer 1 of the second assembly passes between the housing case 9 and the outer periphery of the resin walls (B) 5, 5 of the second assembly and reaches the third assembly. It passes through the third and fourth assemblies through the same path as in the first and second assemblies, reaches the end plate 11, and flows out as a concentrated liquid fluid. In Fig. 14, 26 is a flat bundle of permselective hollow fibers, the width of which is 15d to 50000d (d indicates the outer diameter of the hollow fibers), and the thickness /
It is a tape-like material with a width ratio of 1/20000 to 1/5,
The approximately parallel tapes are arranged so that there are no gaps between them (gaps are left in the figure to aid understanding). The layer made of almost parallel tape is 5°~
Intersect at an angle of 60°, and at the point where the tape intersects 2
The two layers intersect one above the other. The hollow fiber used in the present invention has an outer diameter of 10 to 1000μ.
There is no particular limitation as long as the hollow ratio is 3 to 80% and the membrane wall has permselectivity for fluids. The membrane wall of these hollow fibers may be homogeneous, microporous, anisotropic, or a composite of any of these. Usually, cellulose acetate, aromatic polyamide, etc. are used. It is preferable that the hollow fiber layer is rolled up with a packing density of 45% to 70%; if it is less than 45%, the fluid will flow too easily, and the fluid will be rolled up at the mouth of the cavity of the hollow fiber layer (the first Since the fluid flows into the hollow fiber layer (on the right side in the figure) and does not reach the depths of the cavity, the separation efficiency decreases due to the fluid not flowing uniformly within the hollow fiber layer, and the hollow fiber layer is likely to collapse. Become. Additionally, if it exceeds 70%, the flow of fluid within the hollow fiber layer will deteriorate, and if you want to force it to flow, you will need to increase the fluid supply pressure.
Pressure loss also increases. In addition, the packing density is 50% ~
Preferably it is 65%. In addition, the hollow fibers are
Preferably, they intersect with each other at a winding angle of 5° to 60°. If the winding angle is too small, the hollow fiber layer will easily collapse, and if the winding angle is too large, the length of the hollow fibers will increase, which will increase the pressure loss of permeated water and reduce the amount of permeation. do. Further, the diameter of the cavity formed in the center of the hollow fiber assembly is usually 1 cm to 10 cm, and the thickness of the hollow fiber layer is preferably 5 cm to 50 cm. If the diameter of the cavity is too small, it is necessary to increase the fluid supply pressure, and if it is too large, the hollow fiber layer tends to collapse, and the fluid cannot be supplied radially throughout the length of the hollow fiber layer. There is. Furthermore, if the thickness of the hollow fiber layer is too small, the permeation area of the hollow fibers becomes small and the fluid processing capacity is reduced, and if it is too thick, pressure loss becomes large and there is a drawback that it causes uneven flow. To manufacture the above-mentioned hollow fiber cylindrical layer, a fitting member is usually attached to the shaft of a winding machine, and if necessary, a protective net is covered on top of the fitting member, and the hollow fibers are rolled until the specified thickness is reached. It is sufficient to uniformly wind the thread while traversing it with an appropriate tension, and then pull out only the shaft to make the center hollow. Of course, in this case, the above-mentioned fitting member and protective net are present in the cavity. The fitting member used in the present invention is located in a hollow portion existing inside the hollow fiber cylindrical layer, partially supports the hollow fiber layer in the hollow portion, and uses a fitting member with low resistance due to fluid. It is necessary to use it. Examples include a mesh member, a ring member, and the like.
In addition, if there is a change in the distance between the resin walls (A) and (B), in order to prevent the displacement from being concentrated in one part of the cavity, the resin walls (A) and (B) should be disposed not in one part but in a plurality of parts, preferably three parts.
The two or more members are spaced apart from each other and collectively function as a cavity for allowing fluid to pass through the fiber layer. Furthermore, the fitting member 3 used in the present invention has the role of uniformly dispersing the contractile force due to the tension that acts on the hollow fiber layer 1 during water passage, and prevents the hollow fibers from expanding excessively due to fluid flow resistance. Have a purpose. Therefore, it is preferable that the interval between the fitting members 3, 3 be 1 cm to 3 cm. Furthermore, since the elastic support member 6 used in the present invention employs the fitting member 3, it serves to prevent excessive contraction of the hollow fiber assembly, and prevents the fluid to be treated from being suddenly supplied to the hollow fiber assembly. Its purpose is to absorb the shock that is applied to the hollow fibers when A material that satisfies the relationship E×S/Q≧40 between the elastic modulus E (Kg/cm ² ) of the support member, the total cross-sectional area S (cm ² ), and the flow rate (liters/min) of the supply fluid. , it is preferable to select the form. In other words, the material of the elastic support member is
It is made of ERP, stainless steel, etc., and the number of support members used depends on the type of material, the size of the assembly, etc., but is generally in the range of 2 to 60. Furthermore, in the present invention, the fitting member 3 and the resin wall (A)
It is also important to keep distance between 4 and 4. Also, the interval is 1
It is preferable to set it as cm - 5 cm. With this configuration, it is possible to mainly eliminate the above-described disadvantages caused by applying adhesive to the core tube, that is, the deterioration in separation performance due to retention of the fluid to be treated. The resin constituting the resin wall (A) 4 and the resin wall (B) 5 of the present invention is preferably a fluid liquid before curing and becomes a hard solid upon curing. Typical examples include epoxy, polyester, silicone, and polyurethane resins. The hollow fiber assembly of the present invention has the above-mentioned structure, so it is flexible, and there is almost no fluid dead space within the hollow fiber layer, and there is no obstruction like the conventional core tube, so there is no pressure. It has the advantages of very low loss, very uniform flow within the hollow fiber layer, and very high separation efficiency. Furthermore, the separation performance does not deteriorate even in repeated intermittent operation and operation in which the fluid to be treated flows at a high flow rate, and the durability is excellent. In addition, even if a plurality of assemblies are used in combination, each individual assembly has the same function and effect as when a single assembly is used. Next, an example will be described. Example 1 Three mesh-like fitting members with an outer diameter of 27 mm and a length of 300 mm were attached to a shaft with a diameter of 20 mm at a distance of 30 mm from each other, the surfaces of the fitting members were covered with a soft protective net, and then A hollow fiber for reverse osmosis made of cellulose acetate with an outer diameter of 230μ and an inner diameter of 100μ is wound while traversing from one end to the other with a packing density of 50%, a winding angle of 8° to 30°, and a constant number of winds. Forming a hollow fiber cylindrical layer with a length of 118 mm and a length of 1260 mm,
The surface was coated with a flow screen, and then only the shaft was removed to form a cavity in the center. Fitting member 3 applies epoxy resin to both ends of the formed hollow fiber layer.
Inject the resin to a position 20mm away from the wall, solidify and form the resin wall.
(A) and (B), and attach three elastic support members (FRP bars) with a width of 10 mm and a thickness of 2 mm between both resin walls (A) and (B), and one of the resin walls ( A hollow fiber assembly was prepared by cutting A) 4 at right angles to the axis of the hollow fiber layer so that the hollow fibers penetrated the resin wall and opened outward. Note that the end of the protective net is also covered with resin wall (A) 4.
and 20mm apart. Incorporating this into the membrane separation device shown in Figure 4,
25℃, 30Kg/cm ² using 1500ppm salt water as feed water
Reverse osmosis tests were conducted by circulating the feed water at a pressure of . The results are shown in Table 1. Comparative Example 1 Instead of the hollow fiber assembly of Example 1, a single core tube with numerous small holes bored in the center of the previous hollow fiber layer was used, and the tube was buried in the resin wall. A hollow fiber assembly having a similar structure was prepared and installed in the membrane separation apparatus shown in FIG. 4, and a reverse osmosis test was conducted under the same conditions as in Example 1. The results are shown in Table 1. The diameter of the core tube was 27 mm, the length was 1 m, the diameter of the small holes drilled in the core tube was 1.7 mm, and the number of holes was 70, and the winding density and winding angle of the hollow fiber layer were the same as in the examples.

【table】

[Table] Supply flow rate
〓 In permeate〓

Claims (1)

[Scope of Claims] 1. A hollow fiber assembly in which permselective hollow fibers are arranged in a cylindrical shape, and a hollow fiber cylindrical layer formed by cross-arranging hollow fibers having an open end surface;
A cavity existing inside the hollow fiber cylindrical layer;
A plurality of fitting cylindrical members spaced apart from each other in the hollow portion and the hollow fibers at the open ends of the hollow fibers are made of resin with no gap between the fibers and the resin wall (A). a resin wall (A) disposed so as to open on the outer surface of the wall (A) and disposed apart from the fitting member; and an end of the assembly at the other end of the assembly. A permselective hollow fiber assembly comprising a resin wall (B) that fixes the resin wall (B), an elastic support member that regulates the distance between the resin walls (A) and (B), and a fluid supply conduit. 2. The permselective hollow fiber assembly according to claim 1, wherein the plurality of mutually spaced fitting cylindrical members in the hollow portion are configured such that the cylindrical members are spaced from each other by 1 to 3 cm. 3 In claim 1 or 2, the fitting cylinder member located in the cavity and on the resin wall (A) side is
A permselective hollow fiber assembly configured 1 to 5 cm away from the resin wall (A). 4 In claim 1, 2 or 3,
A permselective hollow fiber assembly comprising a plurality of mutually spaced fitting cylinder members in a hollow portion, the outer periphery of which is covered with a net-like fabric. 5 In claims 1 to 3 or 4,
Between the elastic modulus E (Kg/cm ² ) of the elastic support member that regulates the distance between both resin walls (A) and (B), the total cross-sectional area S (cm ² ), and the flow rate of the supplied fluid (liters/min). A permselective hollow fiber assembly that satisfies the relationship E×S/Q≧40.