WO2014141967A1

WO2014141967A1 - Separating membrane element

Info

Publication number: WO2014141967A1
Application number: PCT/JP2014/055634
Authority: WO
Inventors: 正彬竹中; 智正片山; 朗片山
Original assignee: 東レ株式会社
Priority date: 2013-03-11
Filing date: 2014-03-05
Publication date: 2014-09-18
Also published as: JPWO2014141967A1

Abstract

Provided is a separating membrane element using anti-telescoping plates, which maintain the function of anti-telescoping plates while making it possible to increase the membrane area. The separation membrane element has an upstream anti-telescoping plate (10a) and a downstream anti-telescoping plate (10b). The upstream anti-telescoping plate (10a) is obtained from: a first ring-shaped section (14) on the outside of which a sheath (8) is fitted; a second ring-shaped section (15), the downstream and upstream endfaces of which can engage with the upstream end of the sheath (8) and the downstream end of a seal ring (12) respectively; a third ring-shaped section (16) on the outside of which the seal ring (12) is fitted; and a fourth ring-shaped section (17), the downstream endface of which can engage with the upstream endface of the seal ring (12). The downstream anti-telescoping plate (10b) is obtained from a fifth ring-shaped section (18) on the outside of which the sheath (8) is fitted, and a sixth ring-shaped section (19), the upstream endface of which can engage with the downstream end of the sheath (8).

Description

Separation membrane element

The present invention relates to a separation membrane element using a reverse osmosis membrane.

Separation membranes as water treatment means in seawater desalination and ultrapure water production applications in the semiconductor field, and in various water treatment applications including general brine desalination, organic matter separation, wastewater reuse, etc. The fluid separation process using the is used. A typical separation membrane includes a reverse osmosis membrane. In this separation process using a membrane, a separation membrane element using a reverse osmosis membrane is used, and its use is rapidly increasing.

The separation membrane element has a structure in which a separation membrane is spirally wound around a collecting pipe together with a permeate channel material and a raw solution channel material. As shown in FIG. 1, the separation membrane element 1 includes a permeate passage material 5 sandwiched between envelope-like membranes formed by adhering three sides of the separation membrane 4, and this is connected to the stock solution passage material 6. One or a plurality of membrane units 7 are prepared and wound around a liquid collecting tube 3 having a liquid collecting hole 2 in a spiral shape. The envelope-like membrane is open on the liquid collection tube 3 side. The stock solution 20 is supplied from one end face of the separation membrane element 1 and processed by the separation membrane 4. The permeate 21 that has permeated through the separation membrane 4 is taken out from the collecting tube 3, and the stock solution 20 that has not permeated through the separation membrane 4 is discharged from the other end face of the separation membrane element 1 as a concentrate.

Usually, the separation membrane element 1 is provided with telescope prevention plates 10 provided with a stock solution flow path 11 for supplying the stock solution 20 to the end surface of the separation membrane element at both ends in the longitudinal direction. It takes the form covered by.

When fluid separation is actually performed using a separation membrane element, a plurality of separation membrane elements are arranged in series in the longitudinal direction in a pressure vessel and used as a separation membrane module. It is necessary to flow the required amount of liquid over the separation membrane surface in order to effectively exhibit the separation performance by the separation membrane and prevent the separation membrane surface from being contaminated. For this reason, 4 to 8 separations are required. In many cases, the membrane elements are housed in series in a pressure vessel. Separation membrane elements arranged in series are closely connected to the telescope prevention plate at the end of the separation membrane element and the telescope prevention plate of the adjacent separation membrane element, and the collecting pipe is connected by a connector. Connected by.

The telescope prevention plate is provided at each end of the separation membrane element in order to prevent the phenomenon that the membrane unit inside the separation membrane element is deformed by the stock solution flowing into the separation membrane element at a high pressure. In general, as shown in FIG. 1, an inner peripheral annular portion that engages with a liquid collecting tube, an outer peripheral annular portion having a diameter substantially equal to the diameter of the separation membrane element, and these annular portions are arranged in a substantially radial direction, that is, A spoke-type telescope prevention plate having a spoke portion connected in the same direction as the radius of the ring (Patent Document 1), a plate punched with a round hole, or a combination of a spoke and a round hole punching plate A round hole punching type telescope prevention plate (Patent Document 2) is used.

In addition, as shown in FIG. 5, the telescope prevention plate generally has an extrapolated seal ring 12 made of rubber having a U-shaped or V-shaped cross section and locks both end faces thereof. It has a structure that can be done. The seal ring 12 expands to the outside due to the pressure at the time of fluid separation, and seals the gap with the inner surface of the pressure vessel 13 so that the entire amount of the stock solution supplied at the time of fluid separation flows into the separation membrane element.

Japanese Patent Laid-Open No. 11-267470 Japanese Laid-Open Patent Publication No. 2005-111473

Incidentally, an increase in membrane area is one of the issues required for the separation membrane element. However, since the inner diameter and length of the pressure vessel are standardized, the outer diameter and length of the separation membrane element are also limited.

On the other hand, the telescope prevention plate is generally provided with the same shape at both the upstream and downstream ends of the separation membrane element, as shown in FIG. It is only necessary to provide the upstream side in view of the required function. Since the seal ring is not extrapolated to the downstream telescope prevention plate, this portion is an extra space.

Accordingly, the present invention provides a telescope prevention plate capable of increasing the film area while maintaining the function of the telescope prevention plate by reducing the excess space of the conventional telescope prevention plate, and separation using the same An object is to provide a membrane element.

The separation membrane element of the present invention for achieving the above object has the following characteristics.

(1) An exterior body is provided on the outer periphery of a spiral wound body in which a separation membrane, a raw liquid flow path material, and a permeate flow path material are wound in a spiral shape, and at both ends of the spiral wound body and the exterior body, respectively. A separation membrane element having a structure in which an upstream telescope prevention plate and a downstream telescope prevention plate are arranged, and used by being loaded in series in a pressure vessel, wherein the upstream telescope prevention plate Are formed on the upstream side of the first annular portion and the first annular portion on which the exterior body is extrapolated, and on the downstream side and the upstream side of the upstream side of the exterior body and on the downstream side of the seal ring, respectively. A second annular portion that can lock the end surface; a third annular portion that is formed on the upstream side of the second annular portion; the seal ring is extrapolated; and an upstream side of the third annular portion; The seal The upstream end face of the groove includes a fourth annular portion that can be locked, and the downstream telescope prevention plate is provided on the downstream side of the fifth annular portion and the fifth annular portion on which the exterior body is extrapolated. A separation membrane element comprising a sixth annular portion formed and capable of locking the downstream end portion of the outer package to the upstream end surface.

(2) The width of the downstream telescope prevention plate in the separation membrane element axial direction is 15% to 60% of the width of the upstream telescope prevention plate in the separation membrane element axial direction, The separation membrane element according to (1).

(3) The separation membrane element according to (1) or (2) above, wherein outer diameters of the fourth annular portion and the sixth annular portion are constant in the axial direction of the separation membrane element.

(4) The separation membrane element according to any one of (1) to (3), wherein the outer diameter of the upstream end is larger than the outer diameter of the downstream end in the fifth annular portion. .

(5) The separation membrane element according to any one of (1) to (4), wherein the fifth annular portion has a groove or a protrusion on an outer periphery.

(6) The separation membrane element according to any one of (1) to (5), wherein the first annular portion has the same shape as the fifth annular portion.

According to the present invention, it is possible to provide a separation membrane element that can increase the membrane area while maintaining the function of the telescope prevention plate.

FIG. 1 is a partially exploded perspective view according to an embodiment of the separation membrane element of the present invention. FIG. 2 is a longitudinal sectional view of an embodiment in which the separation membrane element of the present invention is loaded in a pressure vessel. 3A and 3B are examples of the telescope prevention plate constituting the separation membrane element of the present invention. FIG. 3A is a longitudinal sectional view showing the upstream telescope prevention plate and FIG. 3B is the downstream telescope prevention plate. . 4A and 4B are longitudinal sectional views corresponding to FIGS. 3A and 3B showing another example of the telescope prevention plate. FIG. 5 is a longitudinal sectional view when a conventional separation membrane element is loaded in a pressure vessel.

Hereinafter, the present invention will be described with reference to the drawings schematically showing the best embodiment. However, the scope of the present invention is not limited to these.

FIG. 2 shows an embodiment according to the separation membrane element of the present invention. In this separation membrane element 1, a spiral wound body in which a membrane unit 7 including a separation membrane, a permeate flow path material, and a raw liquid flow path material is spirally wound around a liquid collection tube 3 having a liquid collection hole. Form. An exterior body 8 is formed outside the membrane unit 7 to form the separation membrane element 1. The end face of the separation membrane element 1 is exposed, and the upstream telescope prevention plate 10a and the downstream telescope prevention plate 10b are attached to both ends thereof. The upstream telescope prevention plate 10a and the downstream telescope prevention plate 10b serve to prevent the separation membrane element 1 from being deformed into a telescope shape. The stock solution 20 enters the membrane unit 7 through the stock solution flow path of the upstream telescope prevention plate 10 a, is subjected to membrane separation, and is collected in the liquid collection tube 3 as a permeate 21. The stock solution 20 that has not passed through the separation membrane is discharged from the stock solution flow path of the downstream telescope prevention plate 10b.

A plurality of separation membrane elements 1 configured as described above are accommodated in series in the pressure vessel 13. In each separation membrane element 1, a seal ring 12 is extrapolated to the upstream telescope prevention plate 10 a so that the stock solution 20 enters the membrane unit 7, and seals between the inner wall surface of the pressure vessel 13. . Further, the liquid collecting pipes 3 of the separation membrane elements 1 adjacent to each other are integrally connected via connecting pipes inserted into both the liquid collecting pipes 3.

3A and 3B show examples of the upstream telescope prevention plate and the downstream telescope prevention plate of the present invention, respectively. The upstream telescope prevention plate 10 a includes a first annular portion 14, a second annular portion 15, a third annular portion 16, and a fourth annular portion 17. The first annular portion 14 is connected to the upstream side of the spiral wound body of the membrane unit 7 with the exterior body 8 being extrapolated. The second annular portion 15 is formed on the upstream side of the first annular portion 14, and enables the upstream end portion of the outer package 8 and the downstream end surface of the seal ring to be locked to the downstream and upstream end surfaces, respectively. The third annular portion 16 is formed on the upstream side of the second annular portion 15, and the seal ring 12 is extrapolated. The fourth annular portion 17 is formed on the upstream side of the third annular portion 16 and enables the upstream end surface of the seal ring 12 to be locked to the downstream end surface. Further, the downstream telescope prevention plate 10 b includes a fifth annular portion 18 and a sixth annular portion 19. The fifth annular portion 18 is connected to the upstream side of the spiral wound body of the membrane unit 7 with the exterior body 8 being extrapolated. The sixth annular portion 19 is formed on the downstream side of the fifth annular portion 18 and enables the downstream end portion of the exterior body 8 to be locked to the upstream end surface.

Here, the width of the downstream telescope prevention plate 10b in the separation membrane element axial direction is 60% or less from the point of increase in the membrane area with respect to the width of the upstream telescope prevention plate 10a in the separation membrane element axial direction, and From the viewpoint of securing strength, it is preferably 15% or more. If the width of the downstream telescope prevention plate 10b in the axial direction of the separation membrane element is too small, the strength may be insufficient and the high pressure during operation may not be able to be endured.

Further, it is preferable that the outer diameters of the fourth annular portion 17 and the sixth annular portion 19 are constant in the axial direction of the separation membrane element. In particular, the fourth annular portion 17 and the sixth annular portion 19 have the same shape, that is, the same outer diameter and the same width in the axial direction of the separation membrane element. From the viewpoint of symmetry, it is more preferable.

Further, in the fourth annular portion 17 and the sixth annular portion 19, grooves or protrusions on the outer peripheral surface are provided in a direction parallel to the element axial direction, or in the third annular portion 16, the outer peripheral surface and the inner peripheral surface are formed. By providing the through-hole, it is possible to prevent damage due to a pressure difference generated between the outer peripheral surface and the inner peripheral surface of each annular portion of the telescope prevention plate.

Further, as shown in FIG. 3B, the fifth annular portion 18 has an upstream end having an outer diameter larger than that of the downstream end, or a groove or protrusion 23 on the outer periphery as shown in FIG. 4B. It is preferable from the viewpoint of firmly engaging the exterior body and preventing separation of the downstream telescope prevention plate 10b from the exterior body. Moreover, since it is the same also about the upstream telescope prevention plate 10a, it is more preferable that the 1st annular part 14 is the same shape as the 5th annular part 18 and plane symmetry. That is, the first annular portion 14 has the outer diameter of the downstream end portion larger than the outer diameter of the upstream end portion as shown in FIG. 3A, or has a groove or protrusion 23 on the outer periphery as shown in FIG. 4A. Is preferred.

The material for the upstream telescope prevention plate and the downstream telescope prevention plate is not particularly limited, but from the viewpoint of productivity, cost, and weight reduction, and also consider chemical resistance against various substances contained in the stock solution. And at least one selected from the group consisting of acrylonitrile butadiene styrene copolymer resin (ABS), vinyl chloride resin (PVC), modified polyphenylene oxide resin (PPO), modified polyphenylene ether resin (PPE), and polyoxymethylene resin (POM). It is preferable that Further, at least one selected from this group may be used as the glass fiber reinforced resin (GFRP).

For the exterior body, a fiber reinforced plastic (FRP) shell formed by impregnating a resin with a high modulus fiber and thermosetting it is preferable. Examples of the high modulus fiber include, but are not limited to, glass fiber, carbon fiber, aramid fiber, and metal fiber. The material of the resin is not particularly limited, and examples thereof include, but are not limited to, an epoxy resin, a polyester resin, a polyamide resin, a phenol resin, and a methyl methacrylate resin. When the high elastic modulus fiber and the resin swell, it becomes difficult to accommodate the separation membrane element in the pressure vessel by extending in the direction of the collecting tube axis. In order to suppress this, it is preferable that the high elastic modulus fiber and the resin forming the exterior body have a water absorption rate of 3% or less in terms of a weight change rate when immersed in 90 ° C. warm water for 24 hours. Further, the exterior body is preferably transparent so that a label attached to the outer peripheral surface of the membrane unit can be visually recognized in order to identify the product name, lot number, etc. of the separation membrane element.

For the molding of the exterior body, the high modulus fiber impregnated in the resin is removed from one end (the first annular portion 14 of the upstream telescope prevention plate 10a) of one telescope prevention plate on the membrane unit surrounding side. The outer periphery of the other telescope prevention plate is wound to one end (the fifth annular portion 18 of the downstream telescope prevention plate 10b) of the other telescope prevention plate on the side of the membrane unit surrounding body and thermally cured. In this case, in order to prevent the telescope prevention plate from being detached or damaged from the exterior body when using the separation membrane element, the fibers are arranged in the direction of the collecting tube axis between the end of the telescope prevention plate and the end of the membrane unit. The thickness of the exterior body in the portion that engages with one end of the telescope prevention plate on the side of the membrane unit enclosure is made thicker than the thickness of the exterior body in the axial center portion of the membrane unit enclosure. Is preferred. In addition, when the outer diameter of the membrane unit enclosure is smaller than the outer diameter of one end of the telescope prevention plate on the membrane unit enclosure side, the thickness of the exterior body is reduced to prevent stress concentration in the exterior body. It is preferable that the thickness of the protective plate is gradually reduced from the portion engaging the one end of the membrane unit envelope on the side of the membrane unit envelope to the central portion in the axial direction of the membrane unit envelope.

As for the seal ring, the U-shaped or V-shaped cross section is preferable because it expands outward due to the pressure during fluid separation and seals the gap with the inner surface of the pressure vessel. The material is not particularly limited, and for example, ethylene propylene rubber (EPM, EPDM), nitrile rubber (NBR), or silicon rubber is selected.

According to the separation membrane element of the present invention, it is possible to increase the membrane area while maintaining the function of the telescope prevention plate. That is, since the downstream telescope prevention plate is reduced by the axial width corresponding to the portion necessary for extrapolating the seal ring in the upstream telescope prevention plate, the membrane area can be increased.

<Comparative Example 1>
In the upstream telescope prevention plate, the width of each annular portion in the axial direction of the separation membrane element is defined as the first annular portion 7.2 mm, the second annular portion 4.0 mm, the third annular portion 8.8 mm, and the fourth annular portion 4. 5 mm, 24.5 mm in total, and the downstream telescope prevention plate is the same as the upstream telescope prevention plate, and the length in the element axial direction is 964 mm as shown in FIG. As a result of producing 29-inch 8-inch separation membrane elements, the effective membrane area of the separation membrane elements was about 440 square feet.

<Example 1>
In the upstream telescope prevention plate, the width of each annular portion in the axial direction of the separation membrane element is defined as the first annular portion 7.2 mm, the second annular portion 4.0 mm, the third annular portion 8.8 mm, and the fourth annular portion 4. 0.5 mm and 24.5 mm overall. In the downstream telescope prevention plate, the width of each annular portion in the separation membrane element axial direction was set to a fifth annular portion 7.2 mm, a sixth annular portion 4.0 mm, and a total of 11.2 mm. In this case, the width of the downstream telescope prevention plate in the element axial direction is 46% of that of the upstream telescope prevention plate. As a result of producing separation membrane elements composed of 29 membrane units each having a length of 964 mm in the element axial direction using these telescope prevention plates, the effective membrane of the separation membrane element was obtained. The area was about 446 square feet. That is, compared to the 8-inch separation membrane element produced in Comparative Example 1, the effective membrane area increased by about 1.4%.

Subsequently, a seal ring was extrapolated to the third annular portion of the upstream telescope prevention plate of the separation membrane element and loaded into a pressure vessel, and membrane separation of seawater was performed at an operating pressure of 5.5 MPa for one month. As a result, it was confirmed that the telescope prevention plate was not detached from the outer casing and the membrane unit was not deformed, and the function of the telescope prevention plate was maintained.

DESCRIPTION OF SYMBOLS 1 Separation membrane element 2 Liquid collection hole 3 Liquid collection pipe 4 Separation membrane 5 Permeate flow path material 6 Stock solution flow path material 7 Membrane unit 8 Exterior body 10 Telescope prevention plate 10a Upstream telescope prevention plate 10b Downstream telescope prevention Plate 11 Stock solution flow path 12 Seal ring 13 Pressure vessel 14 First annular portion 15 Second annular portion 16 Third annular portion 17 Fourth annular portion 18 Fifth annular portion 19 Sixth annular portion 20 Stock solution 21 Permeate

Claims

An exterior body is provided on the outer periphery of a spiral wound body in which a separation membrane, a raw liquid flow path material, and a permeate flow path material are wound in a spiral shape, and an upstream telescope is provided at each end of the spiral wound body and the exterior body. A separation membrane element that has a structure in which a scope prevention plate and a downstream telescope prevention plate are disposed, and is used by being loaded in series in a pressure vessel, wherein the upstream telescope prevention plate is A first annular portion on which the exterior body is extrapolated and an upstream end surface of the exterior body and a downstream end surface of the seal ring are respectively formed on the upstream side and the downstream end surface of the first annular portion. A second annular portion that can be stopped, a third annular portion that is formed on the upstream side of the second annular portion, and on which the seal ring is extrapolated; an upstream side of the third annular portion; Of the seal ring The downstream end surface of the downstream telescope prevention plate is formed on the downstream side of the fifth annular portion and the fifth annular portion on which the exterior body is extrapolated. A separation membrane element comprising a sixth annular portion capable of locking the downstream end portion of the outer package to the upstream end surface.
The width in the separation membrane element axial direction of the downstream telescope prevention plate is 15% or more and 60% or less of the width in the separation membrane element axial direction of the upstream telescope prevention plate. The separation membrane element described in 1.
The separation membrane element according to claim 1 or 2, wherein the outer diameters of the fourth annular portion and the sixth annular portion are constant in the axial direction of the separation membrane element.
4. The separation membrane element according to claim 1, wherein, in the fifth annular portion, the outer diameter of the upstream end is larger than the outer diameter of the downstream end.
The separation membrane element according to any one of claims 1 to 4, wherein the fifth annular portion has a groove or a protrusion on an outer periphery.
6. The separation membrane element according to claim 1, wherein the first annular portion has the same shape as the fifth annular portion.