JP2007111674A - Spiral separation membrane element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a spiral separation membrane element in which the pressure loss to be caused when permeated water flows in a water collection pipe can be decreased without changing the outside and inside diameters of the water collection pipe. <P>SOLUTION: The spiral separation membrane element is formed by spirally winding a separation membrane 1, a supply-side flow passage material 2 and a permeated water-side flow passage material 3 around the perforated water collection pipe 5 in a laminated state. A plurality of grooves 5a each extending along the axial direction of the water collection pipe 5 are arranged on the inner peripheral surface of the water collection pipe 5. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a spiral type separation membrane element that separates components present in a liquid, and more particularly, to reduce a pressure loss during permeate flow in a water collection pipe, a groove is formed on the inner peripheral surface of the water collection pipe. The present invention relates to a spiral separation membrane element.

  As a structure of a conventional spiral separation membrane element, one or a plurality of laminates of a separation membrane, a supply-side channel material, and a permeate-side channel material are wound around a perforated hollow water collecting pipe. Those are known (for example, see Patent Document 1). Usually, a plurality of elements are used by being loaded into a vessel which is a pressure vessel.

  In this membrane element, the stock solution is supplied from one end surface, filtered through the separation membrane while flowing along the supply-side channel material, and the concentrated solution is taken out from the other end surface. The permeate filtered through the separation membrane flows along the permeate-side channel material, flows in from the holes of the water collection pipe, and flows in the water collection pipe. Thus, since permeate flows through the water collection pipe, pressure loss (flow resistance) occurs. Since this pressure loss is an energy loss during operation, it is better to reduce the pressure loss.

  As a method for reducing the pressure loss of the water collecting pipe, a means for increasing the inner diameter of the water collecting pipe can be considered. However, since the outer diameter of the spiral separation membrane element is determined, there is a problem that when the inner diameter of the water collecting pipe is increased, the membrane area of the separation membrane used for the element is reduced and the permeation performance of the element is lowered. For this reason, there are limitations on measures to increase the diameter of the water collection pipe.

  In addition, a method of reducing the thickness of the water collecting pipe and increasing only the inner diameter is conceivable, but there are problems such as a decrease in strength of the water collecting pipe and a need to change the diameter of a joint or the like connecting the water collecting pipe. Therefore, it is not a preferable method.

JP 10-137558 A

  Therefore, an object of the present invention is to provide a spiral separation membrane element that can reduce pressure loss due to the permeate flow in the water collection pipe without changing the outer diameter and inner diameter of the water collection pipe.

  In order to achieve the above-mentioned object, the present inventors diligently studied the pressure loss of the water collecting pipe, and by providing a plurality of grooves extending along the axial direction on the inner peripheral surface of the water collecting pipe, The present inventors have found that loss can be reduced and have completed the present invention.

  That is, the spiral separation membrane element of the present invention includes a spiral separation membrane in which a separation membrane, a supply-side flow path material, and a permeate-side flow path material are spirally wound around a perforated water collecting pipe. In the element, the inner peripheral surface of the water collecting pipe has a plurality of grooves extending along the axial direction of the water collecting pipe.

  According to the present invention, since only the grooves are provided on the inner peripheral surface of the water collecting pipe, the outer diameter and inner diameter of the water collecting pipe do not change, so the membrane area of the separation membrane is not reduced, and the strength of the water collecting pipe is reduced. There is no problem. Moreover, since it has several groove | channels extended along the axial direction in the internal peripheral surface of a water collection pipe | tube, the pressure loss by a permeate flow can be reduced by reducing turbulent frictional resistance by the riblet effect.

  In the above, it is preferable that the plurality of grooves are grooves parallel to the axial direction of the water collecting pipe. Thus, when the groove is parallel to the axial direction, the pressure loss can be further reduced, and the workability is also improved.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a process diagram showing an example of a method for producing a spiral separation membrane element of the present invention. FIG. 2 is a partially broken perspective view showing an example of the spiral separation membrane element of the present invention.

  The spiral type separation membrane element of the present invention is different from the conventional one only in the shape of the inner peripheral surface of the water collecting pipe, and the structure of the conventional spiral type separation membrane element is applied to other structures and materials. can do.

  As shown in FIGS. 1 and 2, the spiral separation membrane element of the present invention includes a separation membrane 1, a supply-side flow channel material 2, and a permeation-side flow channel material 3 in a laminated state, and around a perforated water collecting pipe 5. It is wound in a spiral shape. The cylindrical wound body R is usually provided with a sealing portion for preventing mixing of the supply side fluid and the permeation side fluid. The sealing portion includes a both-end sealing portion 11 and an outer peripheral side sealing portion 12.

  As shown in FIG. 2, both ends of the separation membrane 1 facing each other through the permeate-side flow path member 3 are sealed by a both-end sealing portion 11 and between a plurality of both-end sealing portions 11 arranged in a spiral shape. The supply-side flow path material 2 is interposed between them. Moreover, the outer peripheral side edge part of the separation membrane 1 which opposes via the permeation | transmission side channel material 3 is sealed by the outer peripheral side sealing part 12 along the axial direction.

  The cylindrical wound body R is formed by spirally winding the separation membrane 1, the supply-side flow path member 2, and the permeate-side flow path member 3 around the perforated water collecting pipe 5. It can be manufactured by a process of forming R and a process of forming the sealing portions 11 and 12 for preventing mixing of the supply side fluid and the permeate side fluid.

  Specifically, for example, it can be manufactured by the embodiment shown in FIG. FIG. 1A is an assembled perspective view of a separation membrane unit, and FIG. 1B is a front view showing a state before the separation membrane units are stacked and wound.

  First, as shown in FIG. 1 (a), the supply-side fluid 3 and the permeation-side fluid 3 are stacked while the separation membrane 1 is folded in half. A unit is prepared in which adhesives 4 and 6 for forming a sealing portion that prevents the mixing of these are applied to both end portions in the axial direction and winding end portions of the permeate-side flow path member 3. At this time, a protective tape may be attached to the fold portion of the separation membrane 1.

  As the separation membrane 1, a reverse osmosis membrane, an ultrafiltration membrane, a microfiltration membrane, a gas separation membrane, a degassing membrane, or the like can be used. For the supply-side channel material 2, a net-like material, a mesh-like material, a grooved sheet, a corrugated sheet, or the like can be used. For the permeate-side channel material 3, a net-like material, a mesh-like material, a grooved sheet, a corrugated sheet or the like can be used.

  As the adhesives 4 and 6, any conventionally known adhesives such as urethane adhesives, epoxy adhesives, hot melt adhesives and the like can be used.

  Next, as shown in FIG. 1B, a plurality of the separation membrane units U are stacked, wound around the perforated water collecting pipe 5 in a spiral shape, and then the adhesive is cured by heat or the like. Thus, the cylindrical wound body R is obtained. At that time, sealing around the water collecting pipe 5 may be performed simultaneously. The cylindrical wound body R is trimmed at both ends as necessary in order to adjust the length in the axial direction.

  The number when the separation membrane unit U is stacked is determined according to the required permeation flow rate and may be one or more layers, but about 100 layers is the upper limit in consideration of operability. In addition, the winding number of each separation membrane unit U decreases as the number of stacked separation membrane units U increases.

  In the spiral separation membrane element as described above, the present invention is characterized in that the inner peripheral surface of the water collecting pipe 5 has a plurality of grooves 5 a extending along the axial direction of the water collecting pipe 5. The perforated water collecting pipe 5 has an opening around the pipe, and the material of the water collecting pipe 5 may be any of resin, metal, etc., but plastics such as noryl resin and ABS resin are usually used.

  The groove 5a extends along the axial direction of the water collecting pipe 5 so as to be along the permeate flow direction (the direction of the arrow in FIG. 3), and is preferably a groove parallel to the axial direction of the water collecting pipe. A slightly inclined groove (such as a spiral groove) may be used. Moreover, although the groove 5a may be provided in the full length of the water collection pipe 5, it is provided only in the downstream side where the flow velocity increases, or the groove 5a is provided only in the middle part excluding the end of the water collection pipe 5 involved in the mounting. May be. By providing the groove 5a only at the intermediate portion, an effect that the conventional end seal structure can be used as it is is produced.

The shape of the groove 5a may have any cross-sectional shape, and examples thereof include a V groove, a U groove, a square groove, and a semicircular groove as shown in FIGS. Such a shape of the groove 5a can be formed when the water collecting pipe 5 is formed by extrusion, or by forming a groove after forming. In addition, although the number of the groove | channel 5a is based also on the internal diameter of the water collecting pipe 5, 10-2000 are preferable.
The dimensions of each part of the groove 5a are preferably the following dimensions in consideration of the effect of reducing the pressure loss and the flow change in the vicinity of the wall surface. That is, the height h of the groove 5a is preferably 0.05 to 3 mm, and more preferably 0.1 to 1.5 mm. The width W is preferably 0.05 to 6 mm, and more preferably 0.1 to 3 mm. The interval i is preferably 0 to 5 mm.

  The spiral separation membrane element of the present invention is usually constrained by an exterior material and does not expand in diameter, but the exterior material is formed by winding one or more sheets on the surface of a cylindrical wound body. Can do. As the exterior material, polyester, polypropylene, polyethylene, polyvinyl chloride, glass fiber cloth, or the like can be used.

  The spiral separation membrane element of the present invention can be further provided with a perforated end member for preventing deformation (telescope or the like), a sealing material, a reinforcing material, and the like as necessary.

[Other Embodiments]
(1) In the above-described embodiment, when the separation membrane unit is manufactured, the separation membrane is folded in half and the supply-side channel material is sandwiched. However, the separation membrane unit is folded back alternately using a continuous separation membrane. It is also possible to sandwich the supply-side channel material and the permeation-side channel material. In that case, it suffices to provide a cut-out portion of the permeate-side channel material only for the both-end sealed portions.

  (2) In the above-mentioned embodiment, as shown in FIG. In the present invention, it is also possible to apply the adhesives 4 and 6 on the separation membrane 1 that is folded in two on the permeate-side channel material 3.

  (3) In the above-described embodiment, as shown in FIG. 1, an example in which a spiral membrane element including a plurality of membrane leaves is manufactured using a plurality of separation membrane units U has been described. A spiral membrane element having one membrane leaf may be manufactured using a set of separation membrane units U.

  Examples and the like specifically showing the configuration and effects of the present invention will be described below. In addition, the evaluation item in an Example etc. measured as follows.

(1) Pressure loss Pressure loss was obtained by installing pressure gauges at the inlet and outlet of the water collection pipe and calculating the differential pressure as pressure loss.

(2) Permeation performance 10 minutes after the start of operation, the value of the flow meter in the permeate pipe was converted to the flow rate per day (m ³ / d).

(3) Blocking rate The sample was taken 10 minutes after passing the permeate, and the blocking rate (%) was determined from the NaCl concentration based on the stock solution concentration.

Comparative Example 1
A spiral type reverse osmosis membrane element (inner diameter 28.65 mm) having a membrane area of 37 m ² was made using a water collecting tube made of Noryl resin having an inner diameter of 26.7 mm and an outer diameter of 38 mm. The performance of this element was evaluated with a 1500 ppm NaCl aqueous solution under a pressure of 1.55 MPa. As a result, the permeation performance was 41 m ³ / d, and the rejection was 99.77%. At this time, the pressure loss in the water collecting pipe was 242 Pa.

Example 1
Except for using a water collecting pipe made of Noryl resin having 69 V-grooves on the inner peripheral surface parallel to the axial direction of height (h) 1 mm, width (w) 1.3 mm, and interval (i) 0 mm, Made the same element. When the performance of this element was evaluated at 1500 ppm NaCl under the condition of 1.55 MPa, the permeation performance was 42 m ³ / d and the rejection rate was 99.70%. At this time, the pressure loss in the water collecting pipe was 223 Pa. Thus, the pressure loss could be reduced by 7.8% by installing the V groove inside the water collecting pipe.

Process drawing which shows an example of the manufacturing method of the spiral type separation membrane element of this invention The partially broken perspective view which shows an example of the spiral type separation membrane element of this invention The perspective view which shows an example of the principal part of the spiral-type separation membrane element of this invention Sectional drawing which shows the other example of the principal part of the spiral type separation membrane element of this invention Sectional drawing which shows the other example of the principal part of the spiral type separation membrane element of this invention Sectional drawing which shows the other example of the principal part of the spiral type separation membrane element of this invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Separation membrane 2 Supply side flow path material 3 Permeation side flow path material 4 Adhesive 5 Water collecting pipe 5a Groove 6 Adhesive

Claims (2)

In the spiral-type separation membrane element in which the separation membrane, the supply-side channel material and the permeate-side channel material are spirally wound around the perforated water collecting pipe in a laminated state,
A spiral separation membrane element having a plurality of grooves extending along an axial direction of the water collecting pipe on an inner peripheral surface of the water collecting pipe.   The spiral separation membrane element according to claim 1, wherein the plurality of grooves are grooves parallel to the axial direction of the water collecting pipe.

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