JPH04256424A - Hollow fiber membrane module - Google Patents

Abstract

PURPOSE:To obtain a hollow fiber membrane module capable of easily protecting bundle of hollow fiber membrane from swinging, etc., without substantially decreasing the effective area of the membrane by providing projectingly porous or many-opening cylindrical buffer body toward the passage hole of original liquid in the partition wall to the bundle of the hollow fiber membranes. CONSTITUTION:In the membrane modules which the bundle 2 of the hollow fiber membrane is housed in a casing 1, the and part of the bundle 2 is supported in the casing 1 by the partition wall 5 having a passage hole 6 of an original liquid and the end part of the each hollow fiber membrane is opened against the surface of the partition wall 5, and the other end part of the bundle 2 is made free and the other end of the each hollow fiber membrane is closed, the porous or many-opening cylindrical buffer body 7 is provided projectingly in the bundle 2 from the passage hole 6 of the partition wall 5. By this constitution, the part of the bundle 2 is supported in the vicinity of the partition all 5 by projecting cylindrical buffer body 7, and in the case of swinging the hollow fiber membrane, cylindrical buffered body 7 is became to be elastic deformation opposedly and swinging is suppressed and to prevent the breakage of the membrane.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a hollow fiber membrane module used for filtration, purification, and concentration of various stock solutions or recovery of valuable materials.

0002

[Prior art] Membrane modules are used for filtration, purification of various stock solutions,
It is used for concentration or recovery of valuable materials, and in particular, in membrane modules using hollow fiber membranes, the membrane area per unit volume can be increased, so its use is widespread. There are two types of membrane modules: external pressure type and internal pressure type. Generally, external pressure type is more advantageous in terms of pressure loss, cleaning, etc.

As an external pressure type hollow fiber membrane module, FIG.
As shown in Figure 2, a bundle 2' of hollow fiber membranes with one end 3' left open and the other end 4' closed is housed in a cylindrical case 1' with a uniform inner diameter, and is made of resin having a stock solution flow hole 6'. It has been proposed that a partition 5' is cast into one end of the case 1' and one end of the hollow fiber membrane bundle 2' is passed through the partition.

In this hollow fiber membrane module, compared to other external pressure type hollow fiber membrane modules, the stock solution is supplied from the length direction of the hollow fiber membrane bundle, so it is difficult to supply the stock solution from the side hole of the case. In contrast, the hollow fiber membrane does not undergo bending due to the lateral load of the raw solution flow. Further, since there is no partition wall on the downstream side, there are advantages such as the ability to effectively eliminate the accumulation of SS components.

[0005]

[Problem to be solved] However, in this hollow fiber membrane module, since the other end is in a free state,
When the filling rate of the hollow fiber membrane is low or when backwashing is performed by injecting gas from the other end of the case, the hollow fiber membrane vibrates sideways and stress is concentrated at the root of the hollow fiber membrane on the back side of the resin partition wall. hollow fiber membranes are easily damaged. This stress concentration is caused by a sudden change in the elastic modulus at the boundary between the back surface of the resin partition wall and the hollow fiber membrane. In order to alleviate such stress concentration, it is known to provide a reinforcing body having an intermediate elastic modulus at the base of the hollow fiber membrane. However, the spacing between the hollow fiber membranes is narrow, and it is not easy to provide effective reinforcement at the base of each hollow fiber membrane. Furthermore, since the surface of the hollow fiber membrane is covered with the reinforcing body, a decrease in the effective area of the membrane is unavoidable.

An object of the present invention is to provide a hollow fiber membrane module that can easily protect the hollow fiber membrane bundle from lateral vibration, etc., while leaving the effective area of the membrane essentially unchanged in the above-mentioned external pressure type hollow fiber membrane module. It's about doing.

[0007]

[Means for Solving the Problems] In the hollow fiber membrane module of the present invention, a hollow fiber membrane bundle is housed in a case, and one end of the hollow fiber membrane bundle is supported in the case by a partition wall having a stock solution passage hole. , one end of each hollow fiber membrane is opened to the partition wall surface,
In a membrane module in which the other end of the hollow fiber membrane bundle is left in a free state and the other end of each hollow fiber membrane is closed, a cylindrical shape with porous or multi-spaced holes is inserted into the hollow fiber membrane bundle from the stock solution passage hole of the partition wall. This configuration is characterized by a buffer provided protrudingly.

[0008]

[Function] The hollow fiber membrane bundle near the partition wall is supported by the cylindrical buffer protruding from the stock solution passage hole in the partition wall, so when the hollow fiber membranes try to sway laterally, the cylindrical buffer body responds to the lateral swing. The body elastically deforms and generates a reaction force that prevents the lateral vibration. Therefore, the lateral vibration of the hollow fiber membrane can be suppressed,
Membrane breakage can be prevented.

[0009]

[Embodiments] Hereinafter, embodiments of the present invention will be explained with reference to the drawings. FIG. 1 is an explanatory diagram showing an embodiment of the present invention, and FIG. 2 is a sectional view taken along line II-II in FIG. In FIGS. 1 and 2, 1 is a cylindrical case, for example, made of plastic. 2 is a hollow fiber membrane bundle, which is housed in the case 1. One end 3 of each hollow fiber membrane is left open, and the other end 4 is closed. Reference numeral 5 denotes a resin partition wall cast at one end of the case 1, and has a plurality of undiluted solution passage holes 6.

One end of the hollow fiber membrane bundle is supported through the partition wall 5, and the open end 3 of each hollow fiber membrane is open to the surface of the resin partition wall 5. Reference numeral 7 designates a cylindrical buffer having multiple gaps or holes that protrudes from the stock solution passage hole 6 of the resin partition wall 5 into the hollow fiber membrane bundle, and its tip portion is embedded and supported in the resin partition wall. For example, a cylindrical net can be used as the cylindrical buffer. 8 is a joint, which has a plurality of distribution pipes 9 corresponding to the concentrate passage hole 6, each distribution pipe 9 is inserted into the concentrate passage hole 6 through packing, and the case 1 and the joint 8 are packed together. They are also fastened together by a tightening ring 10. Reference numeral 11 indicates a permeate extraction hole provided in the joint 8. Reference numeral 12 denotes a joint connected to the other end of the case 1 by a packing and a tightening ring 13.

[0011] To close the other end 4 of the hollow fiber membrane, it is possible to use a method in which the sealing resin is infiltrated by utilizing capillary phenomenon, or by suctioning and depressurizing the hollow interior to infiltrate the sealing resin. The length is 2 to 50 mm, preferably 5 to 15 mm),
It is preferable to use a relatively soft sealing resin such as silicone type or urethane type, and JISA hardness is 10.
~60 is preferred.

[0012] The resin partition wall is made of epoxy type, urethane type,
It can be formed by a single layer or a stack of curable resins such as silicone. Since a high pressure corresponding to the pressure of the stock solution acts on this partition wall, it is necessary to provide pressure resistance that can withstand this high pressure. The larger the number of concentrate passage holes in the partition wall, the more disadvantageous it becomes in terms of pressure resistance, so the number of concentrate passage holes is 1.
It is appropriate to set the number to 10.

[0013] The above-mentioned hollow fiber membrane module is usually used in a vertical arrangement. To process the stock solution, the stock solution is supplied into the case 1 from the distribution pipe 9 of the joint 8 through the partition wall 5, and in the case 1, the stock solution is filtered by the hollow fiber membrane 2. The permeated filtrate is guided from one end 3 of the hollow fiber membrane to the permeate chamber 14 of the joint 8, and then through the permeate outlet 1.
1, and on the other hand, the stock solution concentrated by the above-mentioned filtration is discharged from the joint 12.

In the hollow fiber membrane bundle of the hollow fiber membrane module, one end of the hollow fiber membrane bundle is supported while the other end is free, so it oscillates laterally due to fluctuations in the flow pressure of the stock solution or during backwashing, and due to this lateral oscillation, the cylindrical buffer The body also transforms.

FIG. 3 is a mechanical explanatory diagram in this case, and 2
indicates the hollow fiber membrane, 5 indicates the resin partition wall, and 7 indicates the buffer body, where the second moment of area of the hollow fiber membrane bundle is EI, and the basic coefficient of the buffer body is k (reaction when deformed by a unit amount in the y direction). force), and the amount of lateral deflection at position x is y, then the following holds true, and the general solution is: However, β4=k/4EI. Therefore, by increasing the basic coefficient k of the shock absorber and increasing β, lateral vibration can be suppressed.

[0016] As the above-mentioned cylindrical buffer, it is desirable to use one having a basic coefficient k sufficiently larger than the second moment of area EI of the hollow fiber membrane bundle.
Polyolefin-based, vinyl chloride-based, polyacetal-based,
A cylindrical net made of plastic such as acrylic, polyester, or polycarbonate, or ceramic, or a porous plastic cylinder can be used. The size of the mesh of the cylindrical net or the pores of the porous plastic cylinder must be large enough to avoid clogging by the stock solution, and is determined depending on the type of stock solution and the filtration conditions.

In the above, the protrusion length of the cylindrical buffer, for example, the cylindrical net from the resin partition wall is 3 to 3 times the length (effective length) from the back surface of the resin partition wall to the other end of the hollow fiber membrane. It is desirable to set it to 30%. Below 3%,
The effect of suppressing lateral vibration on the hollow fiber membrane becomes relatively small, and when the ratio exceeds 30%, the concentrate from the concentrate passage hole in the resin partition wall flows preferentially within the cylindrical net and flows into the hollow fiber membrane bundle around the net. Supply of stock solution tends to be insufficient.

In the external pressure type hollow fiber membrane module of the present invention, even if the other end of the hollow fiber membrane bundle is in a free state, the cylindrical buffer body is able to withstand the lateral displacement of the hollow fiber membrane bundle due to the elastic base. Since it performs the same action as the elastic foundation when a load is applied to the beam placed above, its lateral displacement can be sufficiently suppressed, and breakage at the base of the hollow fiber membrane in the resin partition wall can be effectively prevented. This can also be confirmed by comparing the following examples and comparative examples.

Example 1 750 polysulfone hollow fiber membranes with an inner diameter of 1.20 mm and a thickness of 0.4 mm were housed in an acrylic resin case with an inner diameter of 126 mm and a thickness of 7 mm, and 7 pins for forming stock solution passage holes were placed.
Each pin of this cap has an inner diameter of φ30mm and a thickness of 2m.
Insert a cylindrical polyethylene net of size 1.5m in diameter, close one end of the case with this cap, and set the whole thing in a centrifugal casting machine.
Epoxy adhesive was injected into one end of the case, and a resin partition wall was formed by centrifugal molding. The protruding length of the cylindrical net was 8% of the effective length of the hollow fiber membrane. After completing this centrifugal casting,
The pressure inside the hollow fiber membrane was reduced by suction to infiltrate 20 mm of silicone resin into the other end of the hollow fiber membrane, thereby sealing the other end of the hollow fiber membrane.

Example 2 The protrusion length of the cylindrical net was 40% of that in Example 1, and the other aspects were the same as in Example 1.

Example 3 The protruding length of the cylindrical net was 1% of Example 1,
The rest was the same as in Example 1.

Comparative Example The cylindrical net was not used, and the other conditions were the same as in Example 1. For each of these example products and comparative example products,
25℃ while venting 25℃ air for 20 seconds every 90 seconds.
℃ water at a flow rate of 280 L/min for 25 hours, and then an air leak test was conducted to determine the number of hollow fiber membranes lost. In Examples 1 and 2,
No damage to the hollow fiber membrane was observed. In Example 3, only one hollow fiber membrane was damaged. On the other hand, in the comparative example, as many as five hollow fiber membranes were observed to be damaged.

[0023] Regarding each of the above examples and comparative examples,
Sewer system wastewater at 25℃ (SS concentration 320mg/L)
) at a flow rate of 200 L/min and a pressure of 1 kg/cm2 for 1 hour, the permeation flow rate of the hollow fiber membrane module (m3/d)
When measured, it was 3.2 for Example Product 1, and 3.2 for Example Product 2.
It was 2.9 for the product of Example 3, and 3.3 for the product of Example 3, which was fully comparable to 3.3 of the product of Comparative Example.

[0024]

Effects of the Invention The hollow fiber membrane module of the present invention has the above-described configuration, and even if the other end of the hollow fiber membrane bundle is in a free state, the stock solution passage of the resin partition that supports one end of the hollow fiber membrane bundle is By simply protruding a multi-gap cylindrical buffer such as a cylindrical net into the hollow fiber membrane from within the hole, the lateral vibration of the hollow fiber membrane bundle can be sufficiently suppressed and breakage of the hollow fiber membrane can be prevented. Therefore, membrane breakage due to lateral vibration of the hollow fiber membrane can be prevented with a simple configuration.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing an embodiment of the present invention.

FIG. 2 is a sectional view taken along line II-II in FIG. 1;

FIG. 3 is an explanatory diagram showing the mechanical action of the cylindrical buffer in the hollow fiber membrane module of the present invention.

FIG. 4 is an explanatory diagram showing a conventional example.

[Explanation of symbols]

1 Tubular case 2 Hollow fiber membrane bundle 3 One end of hollow fiber membrane 4 Hollow fiber membrane other end 5 Resin partition wall 6 Stock solution passage hole 7 Cylindrical buffer

Claims (3)

[Claims] Claim 1: A hollow fiber membrane bundle is housed in a case, one end of the hollow fiber membrane bundle is supported in the case by a partition wall having a stock solution passage hole, and one end of each hollow fiber membrane is opened on the surface of the partition wall. In a membrane module in which the other end of the hollow fiber membrane bundle is left free and the other end of each hollow fiber membrane is closed, porous or multi-gap holes are formed in the hollow fiber membrane bundle from the stock solution passage hole of the partition wall. A hollow fiber membrane module characterized by a protruding cylindrical buffer. 2. The hollow fiber membrane module according to claim 1, wherein the cylindrical buffer is made of a net. 3. The hollow fiber membrane module according to claim 2, wherein the protruding length of the net is 3 to 30% of the length of the hollow fiber membrane from the back surface of the partition wall to the other end of the hollow fiber membrane.