JP2878437B2 - External pressure type hollow fiber membrane module - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial application field) The present invention relates to an external pressure used for separating a solid substance, a specific liquid or a gas from a stock solution in a manufacturing process such as wastewater treatment, pure water, food, or culture. The present invention relates to a hollow fiber membrane module.

(Prior Art) In a manufacturing process such as wastewater treatment, pure water, food, or culture, when a solid substance, a specific liquid or a gas is separated from a stock solution, a membrane module may be used.

In a membrane module using a hollow fiber membrane, a large membrane area per unit volume can be obtained.
This is advantageous for downsizing the module. In particular, the vertical hollow fiber membrane module is advantageous for improving the processing capacity per unit installation space. For example, water treatment at a nuclear power plant (especially, condensate purification water treatment at a BWR type nuclear power plant) And ultra-pure water production (especially pretreatment for RO treatment in ultra-pure water production).

Modules using hollow fiber membranes include an internal pressure type and an external pressure type. In the external pressure type, the outside of the hollow fiber membrane is used as the raw water side, and the inside of the hollow fiber membrane is used as the permeated liquid side.

In order to treat raw water by the external pressure type hollow fiber membrane module, raw water is injected into the outer surface side of the hollow fiber membrane, and the raw water is entirely filtered to reach the inside of the hollow fiber membrane. Take out more. In this case, the permeate flow rate in the hollow fiber membrane increases due to the accumulation of the permeate volume per unit length of the membrane as it reaches the end of the hollow fiber membrane,
Since the area of the permeated liquid channel group in the hollow fiber membrane is constant, the flow rate of the permeated liquid increases toward the end of the hollow fiber membrane (for example, when the length is 2 m, there is a difference of about 4 times). Thus, when the pressure change in the longitudinal direction in the hollow fiber membrane becomes steep, for example, when one end of the hollow fiber membrane is closed and the permeate is taken out only from the other end, the internal pressure at the other end is smaller than the internal pressure at one end. Since the permeation flux becomes remarkably high and the permeation flux is proportional to the difference between the external pressure (raw water pressure) and the internal pressure, the load on the other end opening side of the hollow fiber membrane (load of solid substances contained in the raw water) is remarkably biased. However, there is a concern about early membrane contamination and the accompanying pressure rise and mechanical deterioration.

Conventionally, in order to eliminate such disadvantages of the external pressure type vertical hollow fiber membrane module, a double-end water collecting type as shown in FIG. 5 has been proposed.

In FIG. 5, reference numeral 6 'denotes a tube plate for partitioning the inside of a processing tower (not shown) into a permeate chamber 62' and a raw water chamber 61 '. A 'is a vertical hollow fiber membrane module, in which a hollow fiber membrane bundle 2',... And a communication pipe 12 'are accommodated in a cylindrical case 1' having a raw water inlet 5 '. Cast resin partition at lower end
31 'and 32' are provided respectively, a permeated liquid collecting chamber cap 4 'is attached to the lower end of the case, and the upper end of the case 1 is suspended from the tube sheet 6'. Thus, the whole of the pressurized raw water in the raw water chamber 61 'is filtered by the hollow fiber membranes 2',..., The permeate in each hollow fiber membrane is divided into both upper and lower directions, and the upward permeate flows from the upper end of the hollow fiber membrane. The permeated liquid flows directly into the permeated liquid chamber 62 ', and the downward permeated liquid flows from the lower end of the hollow fiber membrane through the water collecting chamber 4' and the communication pipe 12 '.
Flow into 62 '. In this case, by using a communication pipe 12 'having a sufficiently large inner diameter such that the fluid flow resistance can be neglected, the length L / 2 of the actual length L is half of the fluid circuit.
It can be equivalent to a module using a hollow fiber membrane with one end open and the other end closed, the permeate flow pressure loss in the hollow fiber membrane can be significantly reduced, and the permeate flow velocity distribution can be made sufficiently uniform.
The above irrationality can be solved.

(Problems to be Solved) However, in the above-mentioned water collecting type external pressure type hollow fiber membrane module, when an external force acts on the cylindrical case 1 ′ during transportation, assembling or installation or backwashing of the module,
The external force is transmitted to the communication pipe 12 'through the resin partition walls 31' and 32 ', and as a result, shear stress is generated at the bonding interface between the resin partition wall and the cylindrical case and the bonding interface between the resin partition wall and the communication pipe. If the external force is large or acts repeatedly, interfacial separation cannot be avoided.

For example, if the cross-sectional area of the cylindrical case is S ₁ , the Young's modulus is E ₁ , the cross-sectional area of the communicating pipe is S ₂ , and the Young's modulus is E ₂ , when a tensile external force F acts on the case 1 ′, the case becomes External force to bear F ₁
Is _{F 1 = E 1 S 1 /} E 1 S 1 + E 2 S 2, the external force F ₂ which communicating tube is _{borne, F 2 = E 2 S 2} / E 1 S 1 + E 2 S 2 , and the communicating pipe to from F ₂ along the resin partition walls is transmitted, the resin septum, F ₂ represented by the formula acts as a shearing force. Sectional area of the cross-sectional area S ₂ of the communicating tube而Ru the fluid flow resistance to the small, must be relatively large, therefore, the F ₂ becomes large, so that the adhesive interface of the resin partition walls Peeling is likely to occur. Under the occurrence of such interfacial separation, leakage of the raw water to the permeated liquid side is inevitable, and the water quality of the permeated liquid is inevitably reduced.

Further, in the external pressure type membrane module of the double-end collecting type shown in FIG. 5, the support of the communication pipe at the time of casting the resin partition is troublesome, and there is a disadvantage that the manufacturing cost is high.

An object of the present invention is to eliminate the occurrence of shear stress at the resin partition walls, stably maintain the adhesive interface of the resin partition walls, and facilitate casting of the resin partition walls even when an external force acts on the cylindrical case. It is an object of the present invention to provide an external pressure type hollow fiber membrane module of a water collecting type at both ends.

(Means for Solving the Problems) In the external pressure type hollow fiber membrane module of the present invention, the inner cross section of the cylindrical case is formed by a partition wall integrally formed on the inner surface of the cylindrical case.
Partitioning into a hollow fiber membrane bundle accommodating section and a permeate passage section, accommodating the hollow fiber membrane bundle in the hollow fiber membrane bundle accommodating section, and both ends of the hollow fiber membrane bundle accommodating section and both ends of the hollow fiber membrane bundle. The space between the hollow fiber membranes is sealed with a resin partition and each end opening of the hollow fiber membrane is opened to the outer surface of each resin partition, and a raw water inlet communicating with the hollow fiber membrane bundle accommodating section is provided in the cylindrical case. The permeated liquid collecting chamber is provided at one end.

(Explanation of Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 is an explanatory view showing an embodiment of the present invention, and FIG.
It is II-II sectional drawing in a figure.

1 and 2, reference numeral 1 denotes a vertical cylindrical case, and as shown in FIG. 2, the inner cross section of the case is formed by a partition wall 10 integrally formed on the inner surface of the cylindrical case.
11 and a permeate passage 12. The cross-sectional area of the hollow fiber membrane bundle housing section 11 is larger than the cross-sectional area of the permeated liquid passage section 12. Are hollow fiber membrane bundles, which are housed in the hollow fiber membrane bundle housing unit 11. Reference numerals 31 and 32 denote resin partition walls formed by casting at upper and lower ends of the hollow fiber membrane bundle accommodating portion 11, respectively.
1,32 open to the outside. Reference numeral 4 denotes a cap for a permeate collection chamber which is watertightly attached to the lower end of the cylindrical case 1 via an O-ring or the like. Reference numeral 5 denotes a raw water inlet provided in the cylindrical case 1 and communicates with the hollow fiber membrane bundle housing 11. Reference numeral 6 denotes a horizontal partition provided in a processing tower (not shown). The partition partitions the inside of the processing tower into a raw water chamber 61 and a permeate chamber 62. The upper end of the cylindrical case 1 is suspended from the partition 6 via a packing or the like.

In the external pressure type hollow fiber membrane module having the water collecting chamber at both ends, the pressurized raw water in the raw water chamber 61 is supplied from the raw water inlet 5 to the cylindrical case 1.
The raw water is pressed into the hollow fiber membrane
, The permeate in the hollow fiber membranes 2,... Is diverted up and down, and the upward flow permeate is directly into the permeate chamber 62, and the downward flow permeate is permeate collection chamber 40 and The liquid flows into the permeated liquid chamber 62 via the permeated liquid passage 12. In this case, the inner diameter of the passage portion 12 is sufficiently large so that the fluid flow resistance in the permeated liquid passage portion 12 can be ignored, and one end of a length L / 2 which is half the actual length L in terms of a fluid circuit. It can be equivalent to a module using a hollow fiber membrane with the other end closed, and the permeate flow pressure loss in the hollow fiber membrane can be significantly reduced.
The permeate flow velocity distribution can be made sufficiently uniform.

In the above-mentioned double-end collecting type external pressure type hollow fiber membrane module, since the hollow fiber membrane bundle accommodating portion 11 and the permeated liquid passage portion 12 are formed integrally with the cylindrical case 1, external force is applied to the cylindrical case 1. Even if it works, the permeated liquid communication pipe 12 'in the conventional module shown in FIG.
The generation of shear stress generated as a reaction force of the external force at 1 'and 32' can be eliminated. Further, the Young's modulus of the hollow fiber membranes 2,... Is significantly smaller than that of the cylindrical case 1 (made of plastic or metal).
Even if an external force acts on the cylindrical case 1, the tensile stress acting on the hollow fiber membrane 2 is very small, so that the external force can be substantially supported only by the cylindrical case 1. Therefore, in the above-mentioned double-ended water collecting type external pressure type hollow fiber membrane module, even when an external force acts on the cylindrical case 1, generation of shear stress at the resin partition walls 31 and 32 can be avoided, and The adhesive interface can be kept stable.

Further, since the permeate passage 12 is formed integrally with the cylindrical case, unlike the conventional example shown in FIG. 5, when the resin partition walls 31 and 32 are cast, the permeate passage 12 'is supported. Therefore, the casting is not troublesome, and the usual casting method can be applied.

In the above, the configuration of the permeated liquid passage portion 12 in the cylindrical case 1 may be such that the cylindrical case wall 1 and the permeated liquid passage portion wall 10 are mechanically integrated, as shown in FIG. 3A. In the configuration, the permeated liquid passage portion 12 is provided on the inner surface of the cylindrical case by two integral partition walls 101, 102, or the tubular portion 103 is integrated with the inner surface of the cylindrical case by the spacer portions 104, 104 to form the tubular portion 103.
A configuration in which the inside is a permeate passage may be used.

As shown in FIG. 4, the external pressure type hollow fiber membrane module can also be used in a mode in which a plurality of modules A,... Are vertically connected via a permeated liquid collecting chamber 40. As the permeate flow rate in the permeate passage 12 increases, the cross-sectional area of the permeate passage 12 is preferably increased toward the upper module.

(Effect of the Invention) The external pressure type hollow fiber membrane module of the present invention having the water collecting type at both ends is configured as described above, and the permeated liquid passage is provided integrally with the cylindrical case. There is no need to interpose a cast resin partition between the passage and, even if an external force acts on the cylindrical case, it is possible to eliminate the occurrence of shear stress at the resin partition and to stably maintain the adhesive interface of the resin partition. . Therefore, the reliability of the module can be improved.

Further, the cylindrical case and the permeated liquid passage member are integrated,
Unlike the case of the conventional example in which these are separate bodies, the resin partition can be cast as usual (similar to an external pressure type hollow fiber membrane module not using a permeate passage tube). Molding can be done easily.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing an embodiment of the present invention, and FIG.
3A and 3B are cross-sectional views each showing another example of the cylindrical case used in the present invention, and FIG. 4 is a vertical cross-sectional view showing another embodiment of the present invention. Figure,
FIG. 5 is a longitudinal sectional view showing a conventional example. DESCRIPTION OF SYMBOLS 1 ... Cylindrical case, 11 ... Hollow fiber membrane bundle accommodating part, 12 ... Permeate liquid passage part 2, ... Hollow fiber membrane, 31, 32 ... Resin partition, 40
...... Permeated liquid collecting chamber.

Claims (1)

(57) [Claims] An inner cross section of a cylindrical case is partitioned into a hollow fiber membrane bundle accommodating portion and a permeated liquid passage portion by a partition formed integrally with the inner surface of the cylindrical case. The membrane bundle is accommodated, and the space between both ends of the hollow fiber membrane bundle accommodating portion and each end of the hollow fiber membrane bundle is sealed with a resin partition and each end opening of the hollow fiber membrane is opened to the outer surface of each resin partition. An external pressure type hollow fiber membrane module, wherein a raw water inlet communicating with the hollow fiber bundle accommodating portion is provided in the cylindrical case, and a permeated liquid collecting chamber is provided at one end of the cylindrical case.