JP2017064598A - Spiral type separation membrane element and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to reduce pressure loss of a spiral type separation membrane element.SOLUTION: A spiral type separation membrane element comprising a permeation fluid collection pipe, plural separation membranes which are wound around the permeation fluid collection pipe, and an encapsulation material which blocks an end of the separation membrane is characterized in that a thickness of the encapsulation material at the end of the separation membrane in a longer direction of the permeation fluid collection pipe is smaller than a thickness of a permeation side flow passage material.SELECTED DRAWING: Figure 8A

Description

  The present invention relates to a spiral separation membrane element used for separating components contained in a fluid such as liquid or gas.

  There are various methods for separating components contained in fluids such as liquid and gas, such as spiral type, flat membrane type, and hollow fiber type elements. In particular, in water treatment applications that remove ionic substances contained in seawater, brine, etc., the use of spiral-type separation membrane elements that can secure a large membrane area in a certain volume and can be separated efficiently is expanded. doing.

In general, a spiral type separation membrane element (hereinafter simply referred to as “separation membrane element”) includes a plurality of separation membranes and a permeated fluid collection tube (hereinafter simply referred to as “collection tube”) that collects fluid that has passed through the separation membrane. ").). A plurality of separation membranes are stacked, and each separation membrane is arranged such that its supply-side surface faces one supply-side surface of adjacent separation membranes, and its permeation-side surface is These are arranged so as to face the other permeation side surface of the adjacent separation membranes.
The separation membrane element further includes a supply-side flow channel material and a permeation-side flow channel material as flow channel materials that form a flow channel by being disposed between the separation membranes. The supply-side channel material is inserted between the supply-side surfaces of the adjacent separation membranes, and the permeation-side channel material is inserted between the permeation-side surfaces of the adjacent separation membranes. The permeation side surface of the adjacent separation membrane is open to the collection tube at one side (the side parallel to and close to the longitudinal direction of the collection tube), and the remaining three sides are between the permeation side surfaces of the adjacent separation membranes. It is closed (sealed). On the other hand, the supply-side surface of the adjacent separation membrane is closed with respect to the collection tube at one side (side parallel to and close to the longitudinal direction of the collection tube), and the remaining three sides are open to the supply side.

The supply fluid flows in from one end face of the separation membrane element wound into a columnar shape (one of the end faces perpendicular to the longitudinal direction of the collection tube), and is supplied to the supply-side flow path formed by the supply-side flow path material. The fluid that has passed through and has not been filtered (not permeated through the separation membrane) becomes a concentrated fluid and flows out from the other end surface (the other end surface perpendicular to the longitudinal direction of the collection tube).
The higher the pressure applied to the supply fluid, the greater the separation membrane element can create a large pressure difference between the front and back surfaces of the separation membrane, the amount of fluid that permeates the separation membrane can be increased, and a larger amount of permeated fluid is taken out. be able to.

  The increase in resistance (that is, pressure loss) generated when the supply fluid passes through the supply-side flow path leads to a decrease in the pressure of the supply fluid, and the amount of water produced in the separation membrane element (permeation per day in one separation membrane element) In the past, various supply-side channel materials having a structure aimed at reducing pressure loss have been reported (for example, see Patent Documents 1 and 2).

  On the other hand, according to the knowledge of the present inventors, even when the supply fluid flows into (or flows out) into the separation membrane element at the end of the separation membrane element, the pressure loss is caused by the rapid contraction (or expansion) of the flow path. Although this will lead to a decrease in the amount of water produced by the element, there are few efforts aimed at reducing the pressure loss.

Patent Document 3 discloses a method for reducing the pressure loss by smoothing the flow of the supply fluid at the inflow portion by projecting the sealing portion of the element end face toward the outside in the honeycomb structure for ceramic filter. Has been.
However, according to the knowledge of the present inventors, in the field of spiral-type separation membrane elements, this method is difficult to produce protrusions due to the sealing part being spiral, or there is a protrusion. Because it is difficult to provide an end plate on the end face, it is difficult to put it to practical use. At present, no useful method has been shown for reducing the pressure loss at the inflow portion of the spiral separation membrane element.

JP 2000-000437 A Japanese Utility Model Publication No.59-44506 JP 2012-91097 A

  An object of the present invention is to reduce the pressure loss that occurs when the supply fluid flows into (or flows out) into the separation membrane element at the end of the separation membrane element.

In order to solve the above problems, the present invention has the following configuration. That is,
A permeating fluid collection tube;
A plurality of separation membranes having a supply side surface and a permeate side surface and wound around the permeate fluid collection tube;
A supply-side channel material that forms a supply-side channel along the supply-side surface of the separation membrane;
A permeate-side channel material forming a permeate-side channel along the permeate-side surface of the separation membrane;
A spiral type comprising: a permeation-side flow path; and a sealing material that closes the separation membrane at a longitudinal end portion of the permeation fluid collection tube and an end portion parallel to the longitudinal direction and far from the permeation fluid collection tube. A separation membrane element,
The thickness of the sealing material at the end of the separation membrane in the longitudinal direction of the permeated fluid collection tube is smaller than the thickness of the permeation side flow path material,
Spiral type separation membrane element.
The thickness of the edge part of the said sealing material in the longitudinal direction of the said permeated fluid collection pipe | tube is 10% or more and 30% or less of the thickness of the said permeation | transmission side flow path material. Spiral type separation membrane element.

  A method for producing a spiral separation membrane element comprising the permeation fluid collection tube and the separation membrane wound around the permeation fluid collection tube, comprising the following steps (a) to (d): For manufacturing a spiral separation membrane element.

(A) A supply-side flow path material is provided along the supply-side surface of the separation membrane to form a supply-side flow path, and a permeation-side flow path material is provided along the permeation-side surface of the separation membrane. Forming a side channel,
(B) Applying and adhering the sealing material to the permeation side surface of the adjacent separation membrane at the longitudinal end portion of the permeated fluid collection tube;
(C) The process of making the thickness of the said sealing material smaller than the thickness of the said permeation | transmission side channel material by pressing the line which apply | coated the said sealing material from the surface of the supply side of the adjoining said separation membrane. (D) A step of winding the separation membrane having undergone the step (c) around the permeated fluid collection tube.

  The separation membrane element of the present invention has a thickness of a sealing material that plays a role of blocking (sealing) the separation membranes at the end portion of the element and preventing the supply fluid (or concentrated fluid) from flowing into the permeate-side flow path. By making it smaller, the water loss performance of the element is improved by reducing pressure loss due to vortices generated when the supply fluid (or concentrated fluid) flows into (or flows out) the separation membrane element.

Schematic showing the structure of a spiral separation membrane element in one embodiment of the present invention Schematic showing the flow of fluid inside the separation membrane element Top view of dot-shaped irregularities used as supply-side channel material Cross-sectional view of dot-shaped irregularities used as supply-side channel material Top view of tricot used as permeate channel material Cross section of tricot used as permeate side channel material Top view of striped irregularities used as permeate channel material Cross-sectional view of striped irregularities used as permeate-side channel material Schematic showing the structure of a spiral separation membrane element in one embodiment of the present invention Schematic which shows the mode of the inflow and outflow of the fluid of the spiral separation membrane element in one Embodiment of this invention 1 is a schematic cross-sectional view of an upstream end portion of a spiral separation membrane element according to an embodiment of the present invention. Cross-sectional schematic diagram of the upstream end of a conventional spiral-type separation membrane element Sectional schematic diagram of the downstream end of the spiral-type separation membrane element in one embodiment of the present invention Cross-sectional schematic diagram of the downstream end of a conventional spiral separation membrane element

  An example of an embodiment of the spiral separation membrane element of the present invention (hereinafter simply referred to as “separation membrane element”) will be described with reference to the drawings.

  As shown in FIG. 1, the separation membrane element 100 is referred to as a separation membrane 1, a supply-side channel material 2, a permeation-side channel material 3, and a permeate fluid collection tube 4 (hereinafter simply referred to as “collection tube”). And a supply side end plate 7 and a transmission side end plate 8. The separation membrane element 100 can separate the supply fluid 101 supplied by means (not shown) into the permeated fluid 102 and the concentrated fluid 103.

  The collection tube 4 is a cylindrical member that is long in one direction (x-axis direction in the drawing). A plurality of collecting holes 5 for introducing permeated fluid into the collecting tube are provided on the side surface of the collecting tube 4.

The separation membrane 1 may be any membrane as long as it has a desired separation performance. As the separation membrane, an NF (Nanofiltration) membrane or an RO (Reverse Osmosis) membrane is preferably used. The separation membrane may include, for example, i) a base material, a separation functional layer, and a porous support layer disposed between the base material and the separation functional layer, or ii) a separation functional layer. And a base material, and a porous support layer may not be provided between the base material and the separation functional layer. Note that the separation membrane of ii) may include a layer having the same configuration as the porous support layer in the separation membrane of i) as a separation functional layer.
As shown in FIG. 2, the separation membrane 1 has a supply side surface 11 in contact with the supply fluid 101 and a permeation side surface 12 in contact with the permeate fluid 102. When the supply fluid is supplied to the supply-side flow path, the supply fluid is divided into a permeated fluid that has passed through the separation membrane from the supply-side surface 11 to the permeate-side surface 12 side, and a concentrated fluid 103 that remains in the supply-side flow path. To be separated. For example, in the case of the separation membrane of i) described above, the separation functional layer is often disposed as the supply side surface and the base material is disposed as the permeation side surface.

The supply-side channel material 2 is a spacer inserted to provide a channel (gap) through which the supply fluid flows between the supply-side surfaces 11 of the separation membrane 1. The supply-side channel material 2 may be any material as long as it has a spacer function, but a net having a mesh structure is preferable because it is inexpensive and sufficiently functions as a spacer.
If the thickness of the supply-side channel material is reduced, the membrane surface linear velocity of the supply fluid increases and the flow of the membrane surface is disturbed, so that the supply fluid permeates the separation membrane due to the difference in concentration of the supply fluid on the membrane surface. This is preferable because the concentration polarization that works to prevent the element from becoming small is reduced, and the performance of the element is improved. On the other hand, the supply-side flow path material should be made too thin from the viewpoint that the fouling substances such as impurities and microorganisms in the supply fluid block the supply-side flow path and the element performance deteriorates and the pressure loss of the element increases. In addition, the average thickness of the supply-side channel material is preferably 0.1 mm or more.
Thus, it has been clarified that the average thickness of the supply-side channel material is 0.1 mm or more and 0.7 mm or less, preferably 0.25 mm or more and 0.5 mm or less.
At this time, the supply-side channel material is cut out to be a sample having a size of 5 cm × 5 cm, the thickness is measured from 30 points from one sample, this is performed for three samples, and the average value obtained in each sample is measured. The value is preferably defined as the average thickness of the supply-side channel material.
However, the supply-side channel material 2 can be changed to other members as long as a gap through which the supply fluid flows is provided between the supply-side surfaces 11 of the separation membrane 1. Further, by using a separation membrane having irregularities formed as the separation membrane 1, the irregularities serve as a flow path, so that the supply-side flow path material 2 can be omitted. When using separation membranes with irregularities formed, the irregularities are dot-shaped as shown in FIG. 3A and FIG. 3B when considering reduction in flow resistance, concentration polarization, and fouling. It is preferable.
The permeate-side channel material 3 is a spacer inserted to provide a channel (gap) through which the permeated fluid flows between the permeate-side surfaces 12 of the separation membrane 1. Any material may be used as the permeation side channel material 3 as long as it has a spacer function, but a structure with low flow resistance and easy flow of the permeated fluid is preferable, and a tricot that forms an uneven structure on the surface is most commonly used. It is done. As shown in FIGS. 4A and 4B, in the tricot, in the cross section perpendicular to the direction of the stitch, the yarn becomes a convex portion to support the separation membrane, and the region between the yarn and the yarn becomes a concave portion, and the permeation that has passed through the separation membrane. A fluid flow path is formed.
If the thickness of the permeate-side channel material is increased, the flow resistance is reduced by increasing the size of the channel, and the permeated fluid can easily flow. On the other hand, from the viewpoint of the membrane area that can be secured in a certain volume, the average thickness of the permeate-side channel material is preferably 0.5 mm or less without making the permeate-side channel material too thick.
Therefore, it has been clarified that the average thickness of the permeate-side channel material is 0.1 mm or more and 0.5 mm or less, preferably 0.2 mm or more and 0.4 mm or less.
At this time, the permeation-side channel material was cut out to be a sample having a size of 5 cm × 5 cm, the thickness was measured from 30 points from one sample, this was performed for three samples, and the average value obtained for each sample The value is preferably defined as the average thickness of the supply-side channel material.
However, the permeation-side flow path member 3 can be changed to another member as long as a gap through which the permeated fluid flows is provided between the permeation-side surfaces of the separation membrane 1. Further, by using a separation membrane having irregularities formed as the separation membrane 1, the irregularity functions as a flow path, so that the permeation side flow path material 3 can be omitted. In the case of using a separation membrane with irregularities formed, it is preferable that the irregularities have a stripe shape as shown in FIGS. 5A and 5B in consideration of reduction of flow resistance.
As shown in FIG. 6, the permeate-side flow path member 3 is disposed between the two permeate-side surfaces 12 in the envelope-shaped membrane pair 6 composed of the separation membrane 1 and the sealant 9. At this time, the permeation-side flow path material 3 is disposed on the inner side of the sealing material application line on two opposite sides of the three sides of the separation membrane 1 to which the sealing material 9 is applied. That is, the permeation side surfaces of the separation membrane are closed by the sealing material 9.
The envelope-shaped membrane pair 6 is formed by two separation membranes that are overlapped with each other so that the permeation-side surface 12 is on the inside, or by one folded separation membrane 1. The planar shape of the envelope-shaped membrane pair 6 is rectangular, and the envelope-shaped membrane pair 6 is closed on three sides by the sealing material 9 and opened on one side. The envelope-shaped membrane pair 6 is disposed so that the opening portion faces the collection tube 4, and is further wound around the collection tube 4. Here, the three sides blocked by the sealing material 9 are the sides of the separation membrane 1 (at the end in the longitudinal direction of the collection tube 4 when the envelope-shaped membrane pair 6 is wound around the collection tube 4 ( 2 sides) and the side of the end of the separation membrane 1 that is parallel to the longitudinal direction of the collection tube 4 and far from the collection tube 4. In the separation membrane element, the plurality of envelope membrane pairs 6 are wound so as to overlap each other. The outer surface of the envelope-shaped membrane pair 6 is a supply-side surface 11, and the adjacent envelope-shaped membrane pairs 6 are arranged so that the supply-side surfaces 11 face each other, and the supply-side flow path member 2 is arranged therebetween. The That is, a supply-side flow path is formed between adjacent envelope-shaped membrane pairs 6, and a permeate-side flow path is formed inside the envelope-shaped film pairs 6.
The opposing separation membranes of the two overlapping envelope membrane pairs 6 are sealed with a sealing material 9 on the side parallel to and close to the longitudinal direction of the collection tube, whereby the supply fluid is blocked from the collection tube. Is done. At this time, the opposing separation membranes of the two overlapping envelope membrane pairs 6 may be a single separation membrane that is continuous and close to the longitudinal direction of the collection tube.
Here, the sealing material 9 refers to a material that can seal between the separation membranes by adhering between two adjacent separation membranes.

  The sealing material is not particularly limited as long as it can withstand cleaning with chemicals such as acid and alkali, and commercially available materials can be used. Moreover, as a form of a sealing material, an adhesive agent, an adhesive tape, a heat bonding film etc. are mentioned, for example.

Adhesives used as the sealing material include instant adhesives and known adhesives including two-component mixed type, hot melt type, thermoplastic resin type, thermosetting resin type, emulsion type and elastomer type adhesives. Agents.
In addition, the method for sealing between separation membranes is not limited to adhesion using a sealing material, and includes heating, welding by laser, ultrasonic waves, and the like. The term “welding” means that the separation membrane 1 is melted by heat, and bonded by being pressurized and cooled.

  The supply side end plate 7 and the transmission side end plate 8 are attached to the upstream end and the downstream end of the wound body, respectively.

  Note that the separation membrane element can include members other than those described above. For example, the periphery of the wound body of the separation membrane may be covered with another member such as a film.

  As shown in FIG. 1, the supply fluid 101 is supplied into a supply-side channel material between the supply-side surfaces 11 of the separation membrane 1 via the supply-side end plate 7. The permeated fluid 102 that has permeated the separation membrane 1 from within the supply-side flow path material passes through the flow path formed in the envelope-shaped membrane pair 6 by the permeation-side flow path material 3, passes through the collection hole 5, and enters the collection tube 4. And flow into. The permeated fluid that has flowed through the collection tube 4 passes through the downstream end plate 8 and is discharged as the permeated fluid 102 to the outside of the separation membrane element 100. The supply fluid that has not permeated the separation membrane becomes the concentrated fluid 103, passes between the supply-side surfaces 11, and is discharged to the outside from the downstream end plate 8. Thus, the supply fluid 101 is separated into the permeate fluid 102 and the concentrated fluid 103.

FIG. 7 shows a state in which the supply fluid 101 flows into the separation membrane element at the upstream end of the element and a state in which the concentrated fluid 103 flows out of the separation membrane element at the downstream end of the element. .
FIG. 8A is a schematic diagram of the DD ′ cross section shown in FIG. 7 at the upstream end of the separation membrane element of the present invention. FIG. 8B is a schematic diagram of the DD ′ cross section shown in FIG. 7 at the upstream end of the conventional separation membrane element. In both cases, the supply fluid flows between the envelope-shaped membrane pair 6 and flows into the supply-side flow path.
In the conventional inflow portion, as shown in FIG. 8B, the thickness H9 of the sealing material 9 at the end of the separation membrane 1 is equal to or greater than the thickness H3 of the permeate-side flow path material 3, and the supply fluid is an envelope-like membrane. When it flows in between the pair 6, it will collide with the sealing edge part of the said envelope-shaped film | membrane, and a flow will be disturb | confused. As a result, a large vortex 20 as shown in FIG. 8B is formed at the sealing end, resulting in a pressure loss.
At this time, the sealing material is cut out so as to be a sample having a size of 3 cm × 3 cm, and the thickness of the end portion of the sealing material is measured at 30 points from one sample, and this is performed for three samples. It is preferable to define the average of the values as the thickness H9 of the sealing material 9. On the other hand, in the inflow portion of the present invention, as shown in FIG. 8A, the end portion of the permeation side flow path member 3 is positioned inside the end portion of the sealing material 9 on the permeate side flow passage side, and is separated. The thickness H9 of the sealing material 9 at the end of the membrane 1 is smaller than the thickness H3 of the permeate-side flow path material 3, and the turbulence of the flow when the supply fluid flows in between the envelope-shaped membrane pair 6 is prevented. Get smaller. As a result, at the upstream end portion of the separation membrane element of the present invention, the vortex 20 formed at the sealed end portion becomes smaller than the conventional one, and the pressure loss is reduced.
FIG. 9A shows a schematic diagram of the EE ′ cross section shown in FIG. 7 at the downstream end of the separation membrane element of the present invention. FIG. 9B is a schematic diagram of the EE ′ cross section shown in FIG. 7 at the upstream end of the conventional separation membrane element. In both cases, the concentrated fluid flows out from between the envelope-shaped membrane pair 6 and out of the supply-side flow path.
In the conventional outflow part, like the inflow part, as shown in FIG. 9B, the thickness H9 of the sealing material 9 at the end of the separation membrane 1 is equal to or greater than the thickness H3 of the permeate-side flow path material 3. When the concentrated fluid flows out from between the pair of envelope-shaped membranes 6, the expanded flow is entangled with the sealed end portion of the envelope-shaped membrane, and a large vortex 30 is formed at the sealed end portion, resulting in a pressure loss.
On the other hand, in the outflow part of the present invention, as shown in FIG. 9A, the end of the permeate-side flow path member 3 is positioned on the inner side of the end of the sealant 9 on the permeate-side flow path side and separated. The thickness H9 of the sealing material 9 at the end of the membrane 1 is smaller than the thickness H3 of the permeate-side flow path material 3, and the entrainment of the flow when the supply fluid flows out from between the envelope-shaped membrane pair 6 occurs. Get smaller. As a result, at the downstream end portion of the separation membrane element of the present invention, the vortex 30 formed at the sealed end portion becomes smaller than the conventional one, and the pressure loss is reduced.
Further, regarding the pressure increase portion 40 that is generated when the supply fluid 101 flows into the supply side flow path member 2, in the conventional form, as shown in FIG. Occurs. On the other hand, in the embodiment of the present invention, as shown in FIG. 8A, it occurs in the region between the supply-side surface 11 of the separation membrane and the supply-side flow path member 2. The pressure increased in the vicinity of the surface on the supply side of the separation membrane is used for the supply fluid to permeate the separation membrane, and thus contributes to the improvement of the water production performance. In this respect, the embodiment of the present invention is excellent.
At this time, if the thickness H9 of the sealing material end of the envelope-shaped membrane pair 6 is reduced, the vortex formed by the inflow of supply fluid (or outflow of concentrated fluid) at the end of the element is reduced, The pressure loss is reduced, which is preferable. Further, when the thickness H9 of the end portion of the sealing material of the envelope-shaped membrane pair 6 is 10% or more than the thickness H3 of the permeation-side flow path material 3, the adhesiveness of the sealing material can be ensured, and the fluid It is preferable because it is possible to suppress a leakage defect that passes through the blocking portion due to the sealing material.
Therefore, the thickness H9 of the end portion of the sealing material of the pair of envelope films 6 is preferably smaller than the thickness H3 of the permeation side flow path material 3 and 10% or more, and 30% of the thickness H3 of the permeation side flow path material 3. More preferably, it is 10% or less. By setting it as such a range, the vortex formed by the inflow of the supply fluid (or the outflow of the concentrated fluid) at the end of the element can be reduced, and the pressure loss is reduced, which is preferable.
<Manufacturing method>
The manufacturing method of the separation membrane element 100 includes the following steps.
(A) Process of processing the envelope-shaped membrane pair 6 from the separation membrane 1 and the sealing material 9 so as to enclose the permeation-side channel material 3 (b) Envelope-shaped membrane pair 6 enclosing the permeation-side channel material; Laminating the supply-side channel material 2 and surrounding it around the collection tube 4;
The manufacturing method of the separation membrane element includes, in addition, a step of manufacturing the separation membrane 1, a step of manufacturing the supply-side flow channel material 2, a step of manufacturing the permeation-side flow channel material 3, an end plate after the step (b), etc. Additional steps such as a step of mounting other members may be included.

In the step (a), an adhesive is applied to three sides of the permeation side surface 12 of the separation membrane 1 (or another material that becomes the sealing material 9 is arranged), and the permeation side surface of the separation membrane 1 12 is arranged so that the permeation-side flow path material 3 is on the inner side of the adhesive application line on the two opposite sides of the three sides coated with the adhesive, and the separation membrane 1 is further disposed thereon. Is arranged so that the separation membrane to which the coating is applied and the permeation side surface 12 face each other. When the adhesive is solidified, an envelope-like membrane pair 6 formed by two separation membranes 1 including one permeation-side flow path material 3 is obtained. At this time, before the adhesive is solidified, the thickness H9 of the sealing material 9 is reduced to that of the permeate-side flow path material 3 by pressing a line to which the adhesive is applied from the surface on the supply side of the envelope film pair 6. The thickness can be smaller than H3. At this time, it is necessary to apply an amount of adhesive corresponding to a desired thickness H9.
If the coating amount is increased, an adhesive force sufficient to seal between the separation membranes can be easily obtained.
On the other hand, if the amount is reduced, it is possible to prevent the adhesive at the time of pressing from spreading more than necessary, and a large effective film area can be secured.

  In the step (b), the envelope film pair 6 is overlapped so that the sealed direction faces the same direction. Between the envelope membrane pair 6, that is, between the supply-side surface 11 of the separation membrane 1, the supply-side flow path member 2 is disposed. The envelope membrane pair 6 and the supply-side flow path material 2 stacked in this way are placed around the collection tube 4 so that one side that is not sealed in the step (a) of the envelope membrane pair 6 is on the inside. Wind.

  Then, a separation membrane element is manufactured by winding a filament around the wound body or attaching end plates to both ends of the collection tube 4 in the longitudinal direction.

The present invention is not limited in any way by the following examples.
(Preparation of separation membrane)
A nonwoven fabric (yield diameter: 1 dtex, thickness: 90 μm, air permeability: 0.9 cc / cm ² / sec) obtained from a papermaking method from polyethylene terephthalate fiber is used as a base material, and 16.0 weight of polysulfone is formed on the base material. %, Dimethylformamide (DMF) solution was cast at room temperature (25 ° C.) with a thickness of 180 μm. After casting, it was immediately immersed in pure water and left for 5 minutes. Thus, a porous support layer (thickness 135 μm) roll made of a fiber-reinforced polysulfone support membrane was produced.

  The porous support layer roll was unwound (unrolled), and an aqueous solution of 1.5% by weight of m-PDA and 5.0% by weight of ε-caprolactam was applied to the surface of the polysulfone support membrane. After removing excess aqueous solution from the surface of the support film by blowing nitrogen from an air nozzle, an n-hexane solution at 25 ° C. containing 0.06% by weight of trimesic acid chloride was applied so that the support film surface was completely wetted. . After that, the excess solution is removed from the membrane by air blow, washed with hot water at 50 ° C., immersed in a 2% glycerin aqueous solution for 1 minute, treated in a hot air oven at 100 ° C. for 3 minutes, and semi-dried. A separation membrane roll was obtained.

  In this way, a separation membrane was obtained in which the base material, the polysulfone support membrane, and the polyamide separation functional layer were sequentially laminated.

(End material thickness)
The sealing material from which the separation membrane was peeled off from the surface was cut out to become a sample having a size of 3 cm × 3 cm. Using the high-precision shape measurement system KS-1100 manufactured by Keyence, the thickness of the end portion of the sealing material is measured from 30 points from one sample, and this is performed for three samples. The average value of the values obtained in step 1 was obtained.
(Thickness of supply side channel material and permeate side channel material)
The channel material was cut out to be a sample having a size of 5 cm × 5 cm. Using the Keyence high precision shape measurement system KS-1100, the thickness of the channel material was measured at 30 locations from one sample, and this was performed on three samples, and the thickness of the channel material was obtained for each sample. Average values were obtained.

(Desalination rate (TDS removal rate))
Saline was used as a supply fluid, and element operation (recovery rate: 15%) was performed at a salt concentration of 500 mg / L, an operation pressure of 0.75 MPa, an operation temperature of 25 ° C., and pH 7. By measuring the salt concentration in the permeating fluid at this time, it was obtained from the following equation.
TDS removal rate (%) = 100 × {1− (TDS concentration in permeate fluid / TDS concentration in raw fluid)}.

(Water production)
The element was operated under the same conditions as the measurement of the desalting rate. At this time, the amount of permeated fluid (cubic meter) per day in one separation membrane element was expressed as the amount of water produced (m ³ / day).

Example 1
Using the above-described separation membrane, tricot as the permeate-side channel material, and urethane adhesive (isocyanate: polyol = 1: 3) as the sealing material, 26 envelope membrane pairs having a width of 930 mm were formed. Produced.
Thereafter, the separation membrane as shown in FIG. 1 is used by using an envelope membrane pair and a net having a thickness of 0.4 mm as the supply-side channel material so that the effective membrane area becomes 37.0 m ² . An element was produced.

  At this time, the thickness H3 of the permeation side channel material and the thickness H9 of the sealing material shown in FIGS. 8A and 9A are H3 = 0.3 mm and H9 = 0.03 mm. The thickness ratio of the material was H9 / H3 = 0.1.

When this element was put in a pressure vessel and operated under the above conditions, the salt rejection was 99.35% and the amount of water produced was 48.4 m ³ / day. Table 1 shows the evaluation results of the conditions and elements together with other examples.

(Example 2)
In Example 2, H3 = 0.3 mm, H9 = 0.09 mm, and the ratio of the thickness of the permeation side flow path material to the sealing material is H9 / H3 = 0.3. Elements were prepared and evaluated in the same manner. As a result, the salt rejection was 99.25% and the amount of water produced was 47.9 m ³ / day.

(Example 3)
In Example 3, H3 = 0.3 mm, H9 = 0.12 mm, and the ratio of the thickness of the permeation side flow path material to the sealing material is H9 / H3 = 0.4. Elements were prepared and evaluated in the same manner. As a result, the salt rejection was 99.28% and the amount of water produced was 46.2 m ³ / day.

Example 4
In Example 4, H3 = 0.3 mm, H9 = 0.18 mm, and the ratio of the thickness of the permeation side flow path material to the sealing material is H9 / H3 = 0.6. Elements were prepared and evaluated in the same manner. As a result, the salt rejection was 99.30% and the amount of water produced was 45.5 m ³ / day.

(Comparative Example 1)
In Comparative Example 1, H3 = 0.3 mm, H9 = 0.3 mm, and the ratio of the thickness of the permeation side flow path material to the sealing material is H9 / H3 = 1.0. Elements were prepared and evaluated in the same manner. As a result, the salt rejection was 99.25% and the amount of water produced was 43.6 m ³ / day.

  In particular, the spiral separation membrane element of the present invention can be suitably used for removing salt from brine or seawater.

DESCRIPTION OF SYMBOLS 1 Separation membrane 11 Supply fluid side surface of separation membrane 12 Permeation fluid side surface of separation membrane 2 Supply side flow path material 3 Permeation side flow path material 4 Permeate fluid collection tube 5 Collection hole 6 Envelope-shaped membrane pair 7 Upstream end Plate 8 Downstream end plate 9 Sealing material 100 Spiral separation membrane element 101 Supply fluid 102 Permeating fluid 103 Concentrated fluid 20 Vortex 30 generated at the inflow side sealing end 30 Vortex generated at the outflow side sealing end 40 Supply fluid Pressure increase part generated when water flows into the supply side channel material H3 Thickness of the permeation side channel material H9

Claims (3)

A permeating fluid collection tube;
A plurality of separation membranes having a supply side surface and a permeate side surface and wound around the permeate fluid collection tube;
A supply-side channel material that forms a supply-side channel along the supply-side surface of the separation membrane;
A permeate-side channel material forming a permeate-side channel along the permeate-side surface of the separation membrane;
A spiral type comprising: a permeation-side flow path; and a sealing material that closes the separation membrane at a longitudinal end portion of the permeation fluid collection tube and an end portion parallel to the longitudinal direction and far from the permeation fluid collection tube. A separation membrane element,
The thickness of the sealing material at the end of the separation membrane in the longitudinal direction of the permeated fluid collection tube is smaller than the thickness of the permeation side flow path material,
Spiral type separation membrane element. The thickness of the edge part of the said sealing material in the longitudinal direction of the said permeated fluid collection pipe | tube is 10% or more and 30% or less of the thickness of the said permeation | transmission side flow path material. Spiral type separation membrane element. A method for producing a spiral separation membrane element comprising the permeation fluid collection tube and the separation membrane wound around the permeation fluid collection tube, comprising the following steps (a) to (d): For manufacturing a spiral separation membrane element.
(A) A supply-side flow path material is provided along the supply-side surface of the separation membrane to form a supply-side flow path, and a permeation-side flow path material is provided along the permeation-side surface of the separation membrane. Forming a side channel,
(B) Applying and adhering the sealing material to the permeation side surface of the adjacent separation membrane at the longitudinal end portion of the permeated fluid collection tube;
(C) The process of making the thickness of the said sealing material smaller than the thickness of the said permeation | transmission side channel material by pressing the line which apply | coated the said sealing material from the surface of the supply side of the adjoining said separation membrane. (D) A step of winding the separation membrane having undergone the step (c) around the permeated fluid collection tube.

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