WO2014208602A1

WO2014208602A1 - Separation membrane element

Info

Publication number: WO2014208602A1
Application number: PCT/JP2014/066851
Authority: WO
Inventors: 岡本宜記; 山田博之; 高木健太朗; 広沢洋帆; 浜田剛志; 木村将弘
Original assignee: 東レ株式会社
Priority date: 2013-06-28
Filing date: 2014-06-25
Publication date: 2014-12-31
Also published as: JPWO2014208602A1

Abstract

The purpose of the present invention is to provide a separation membrane element capable of increasing the fresh water generation amount. The present invention is a separation membrane element comprising a water collecting pipe having a plurality of holes, and a membrane leaf wound around the outer peripheral surface of the water collecting pipe, wherein the membrane leaf comprises a supply-side flow path material, a separation membrane, a first permeation-side flow path material, and a second permeation-side flow path material, the supply-side flow path material, the separation membrane, and the first permeation-side flow path material are disposed in this order, the first permeation-side flow path material is not continuous in the longitudinal direction of the water collecting pipe, the second permeation-side flow path material is a sheet-shaped object, and is present at one end of the membrane leaf and wound around the outer peripheral surface of the water collecting tube while being closest thereto among members constituting the membrane leaf, and the second permeation-side flow path material is in contact with at least an end of the first permeation-side flow path material.

Description

Separation membrane element

The present invention relates to a 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 fluid such as liquid and gas. For example, taking a technique for removing ionic substances contained in seawater, brine, etc. as an example, in recent years, the use of a separation method using a separation membrane element has been expanded as a process for saving energy and resources. Separation membranes used in separation methods using separation membrane elements are classified into microfiltration membranes, ultrafiltration membranes, nanofiltration membranes, reverse osmosis membranes, forward osmosis membranes, and the like in terms of their pore diameter and separation function. These membranes are used, for example, in the production of drinking water from seawater, brine, or water containing harmful substances, in the production of industrial ultrapure water, wastewater treatment, recovery of valuable materials, and the like.

The separation membrane element is supplied with raw fluid on one side of the separation membrane and obtains permeate fluid from the other side. By bundling a large number of separation membranes into a separation membrane element, the membrane area per separation membrane element can be increased, and as a result, the production amount of permeated fluid per separation membrane element can be increased. Can do. Currently, various forms such as a spiral type, a hollow fiber type, a plate and frame type, a rotating flat membrane type, and a flat membrane integrated type have been proposed as separation membrane elements.

For example, a fluid separation membrane element used for reverse osmosis filtration includes a supply-side channel material that supplies raw fluid to the surface of the separation membrane, a separation membrane that separates components contained in the raw fluid, and a supply fluid that permeates the separation membrane. A permeate-side channel material for guiding the permeated fluid separated from the gas to the central tube is incorporated. As the supply-side channel material, a polymer net or the like is used. Further, as the permeate side channel material, a knitted member called a tricot having a smaller interval than the supply side channel material is used for the purpose of preventing the separation membrane from dropping and forming the permeate side channel. Two separation membranes are overlapped with each other via a permeate-side flow path material, and a flow path for permeate fluid is formed between the two separation membranes. A member composed of two separation membranes having a permeate-side flow path material therebetween and a supply-side flow path material are alternately stacked, and a predetermined portion on the opening side of the permeate-side fluid of the laminate is formed into a plurality of holes. It adheres to the outer peripheral surface of the water collection pipe | tube which has and is further wound by spiral shape.

In Patent Document 1 and Patent Document 2, in order to improve the amount of water produced by the separation membrane element, by arranging a permeate-side flow path material that is not continuous in the direction of the water collecting pipe on the back side of the membrane and that has an interval. It has been proposed to reduce the flow resistance on the permeate side and increase the amount of permeate in the separation membrane element. Further, in Patent Document 3, the effective perforated area calculated by multiplying the total area of the perforated portion of the water collection pipe by the aperture ratio of one permeate-side channel material around the water collection pipe is the center pipe. Of the inner cross-sectional area of There has been proposed a method for reducing the pressure loss in the vicinity of the water collecting pipe by setting it to 0 times or more. Further, Patent Document 4 proposes a method in which a porous sheet is wrapped around a water collecting pipe and a permeation side channel material different from the permeation side channel material in the membrane leaf is used.

International Publication No. 2011/152484 International Publication No. 2013/005826 JP 2004-305823 A JP 2003-275547 A

Although the permeation-side pressure loss in the membrane leaf of the spiral separation membrane element can be reduced by the methods of

Patent Documents

1 and 2, it cannot be said that the pressure loss reduction in the vicinity of the water collecting pipe is sufficient. Patent Document 3 describes that a net is used as the permeate-side flow path material, which can reduce the pressure loss in the vicinity of the water collecting pipe, but the permeate-side pressure loss in the membrane leaf is reduced. In other words, the pressure loss reduction effect as a whole of the separation membrane element is not large. Although Patent Document 4 describes that a porous sheet is wrapped around a water collection pipe and a permeation side channel material different from the permeation side channel material adjacent to the separation membrane is used, the permeation in the membrane leaf is described. The effect of reducing the side pressure loss is not sufficient.

An object of the present invention is to provide a separation membrane element that can increase the amount of water produced for the separation membrane element.

In order to achieve the above object, the separation membrane element of the present invention has the following configuration.
Having a water collection tube and a membrane leaf wound around the water collection tube;
The membrane leaf includes a supply-side channel material, a separation membrane, a first permeate-side channel material, and a second permeate-side channel material;
A supply-side channel material is provided on the supply surface side of the separation membrane;
Having the first permeate-side channel material on the permeate surface side of the separation membrane;
The first permeate channel material is not continuous in the longitudinal direction of the water collection pipe;
The second permeate-side channel material is a sheet-like material and is present at one end of the membrane leaf; the second permeate-side channel material is the most of the members constituting the membrane leaf A separation membrane element that is wound around the outer peripheral surface of the water collecting pipe nearby; and the second permeate side channel member is at least in contact with the end portion of the first permeate side channel member .

According to the separation membrane element of the present invention, the amount of water produced can be improved.

It is a top view which shows the state which provided the 1st permeation | transmission side flow path on the separation membrane. It is sectional drawing which shows the state which provided the 1st permeation | transmission side flow path on the separation membrane. It is an example of the separation membrane element of this invention, and is a perspective view which shows the state which expanded some membrane leaves. It is a perspective view which shows the form of a membrane leaf. It is an Example of this invention, Comprising: It is a schematic diagram which shows the form which wound a part of film | membrane leaf. It is an Example of this invention, Comprising: It is a schematic diagram which shows the form which wound a part of film | membrane leaf. It is an Example of this invention, Comprising: It is a schematic diagram which shows the form which wound a part of film | membrane leaf. It is an Example of this invention, Comprising: It is a schematic diagram which shows the form which wound a part of film | membrane leaf. It is a comparative example of this invention, Comprising: It is a schematic diagram which shows the form which wound a part of film | membrane leaf. It is a comparative example of this invention, Comprising: It is a schematic diagram which shows the form which wound a part of film | membrane leaf. It is a comparative example of this invention, Comprising: It is a schematic diagram which shows the form which wound a part of film | membrane leaf. It is a comparative example of this invention, Comprising: It is a schematic diagram which shows the form which wound a part of film | membrane leaf.

Hereinafter, an embodiment of the present invention will be described in detail.

In this document, if the term “X contains Y as a main component” is defined, the Y content in X is 50% by mass, 70% by mass, 80% by mass, 90% by mass. % Or more, or 95 mass% or more. In addition, when there are a plurality of components corresponding to Y, the total amount of these components only needs to satisfy the above range.

[1. Separation membrane)
(1-1) Outline The membrane leaf has a supply-side channel material, a separation membrane, and a permeation-side channel material.

The separation membrane is a membrane that separates components in the fluid supplied to the surface of the separation membrane and can obtain a permeated fluid that has permeated the separation membrane. A membrane leaf is formed by the separation membrane, the supply-side channel material on the supply side of the separation membrane, and the permeation-side channel material on the permeation side surface of the separation membrane.

As an example of such a separation membrane, as shown in FIGS. 1 and 2, a first permeate-side flow path material 3 exists near the separation membrane 1 of the present embodiment. The separation membrane 1 has a supply-side surface 11 and a permeation-side surface 22.

In this document, the “supply side surface” of the separation membrane means a surface on the side of the separation membrane where the raw fluid is supplied. The “transmission side surface” means the opposite side surface. As will be described later, when the separation membrane main body includes a base material and a separation functional layer, generally, the separation functional layer is in the direction of the surface on the supply side, and the surface on the base material side is the surface on the transmission side.

The first permeation side flow path material 3 is provided on the permeation side surface 12 so as to form a flow path. Details of each part of the separation membrane 1 will be described later.

In this specification, the 1st direction is the circumference direction of a membrane leaf, and it is length about a membrane leaf, a separation membrane, the 1st permeation side channel material, the 2nd permeation side channel material, and a supply side channel material. It is called a direction, and is the direction of the y-axis in the drawing. The second direction is the longitudinal direction of the water collecting pipe, and is called the width direction with respect to the membrane leaf, the separation membrane, the first permeate side channel material, the second permeate side channel material, and the supply side channel material. The direction of the sign x-axis. The z axis corresponds to the thickness direction of the separation membrane or separation membrane leaf.

(1-2) Separation membrane <Overview>
As the separation membrane, a membrane having separation performance according to the method of use, purpose and the like is used. The separation membrane may be a single layer or a composite membrane comprising a separation functional layer and a substrate. In the composite membrane, a porous support layer may be further provided between the separation functional layer and the substrate.

<Separation function layer>
The thickness of the separation functional layer is not limited to a specific value, but is preferably 5 to 3000 nm from the viewpoint of separation performance and permeation performance. In particular, a reverse osmosis membrane, a forward osmosis membrane, and a nanofiltration membrane preferably have a thickness of 5 to 300 nm.

The thickness of the separation functional layer can be applied to the separation film thickness measurement method so far. For example, the separation membrane is embedded with resin, and an ultrathin section is prepared by cutting the separation membrane, and the obtained section is subjected to processing such as staining. Thereafter, the thickness can be measured by observing with a transmission electron microscope. Further, when the separation functional layer has a pleat structure, measurement is made at intervals of, for example, 50 nm in the cross-sectional length direction of the pleat structure located above the porous support layer, and the number of pleats is measured to obtain 20 from the average. be able to.

The separation function layer may be a layer having both a separation function and a support function, or may have only a separation function. The “separation function layer” refers to a layer having at least a separation function.

When the separation functional layer has both a separation function and a support function, a layer containing a polymer selected from cellulose, polyvinylidene fluoride, polyethersulfone, and polysulfone as a main component is preferably applied as the separation functional layer.

On the other hand, as the separation functional layer, a crosslinked polymer is preferably used in terms of easy control of the pore diameter and excellent durability. In particular, a polyamide separation functional layer obtained by polycondensation of a polyfunctional amine and a polyfunctional acid halide, an organic-inorganic hybrid functional layer, or the like is preferably used in terms of excellent separation performance of components in the raw fluid. . These separation functional layers can be formed by polycondensation of monomers on the porous support layer.

For example, the separation functional layer can contain polyamide as a main component. Such a film can be formed by interfacial polycondensation of a polyfunctional amine and a polyfunctional acid halide by a known method. For example, a polyfunctional amine aqueous solution is applied on the porous support layer, an excess polyfunctional amine aqueous solution is removed with an air knife or the like, and then an organic solvent solution containing a polyfunctional acid halide is applied. Condensation occurs and a polyamide separation functional layer is obtained.

Further, the separation functional layer may have an organic-inorganic hybrid structure having a silicon atom or the like. The separation functional layer having an organic-inorganic hybrid structure includes, for example, the following compounds:
(A) a silicon compound in which a reactive group and a hydrolyzable group having an ethylenically unsaturated group are directly bonded to a silicon atom, and (B) a compound other than the compound (A), which has an ethylenically unsaturated group Compounds can be included. Specifically, the separation functional layer may contain a condensate of the hydrolyzable group of the compound (A) and a polymer of the ethylenically unsaturated group of the compounds (A) and / or (B). That is, the separation functional layer is
A polymer formed by condensation and / or polymerization of only the compound (A),
-The polymer formed by superposing | polymerizing only a compound (B),-At least 1 sort (s) of a polymer of the copolymer of a compound (A) and a compound (B) can be contained. The polymer includes a condensate. In the copolymer of the compound (A) and the compound (B), the compound (A) may be condensed through a hydrolyzable group.

The hybrid structure can be formed by a known method. An example of a method for forming a hybrid structure is as follows. A reaction solution containing the compound (A) and the compound (B) is applied on the porous support layer. In order to condense the hydrolyzable group after removing the excess reaction solution, heat treatment may be performed. As a method for polymerizing the ethylenically unsaturated groups of the compound (A) and the compound (B), a means selected from heat treatment, electromagnetic wave irradiation, electron beam irradiation, and plasma irradiation may be performed. For the purpose of increasing the polymerization rate, a polymerization initiator, a polymerization accelerator and the like can be added during the formation of the separation functional layer.

For any separation functional layer, the surface of the membrane may be hydrophilized with an alcohol-containing aqueous solution, an alkaline aqueous solution, or a solution containing polyvinyl alcohol or an acrylic acid polymer before use.

<Porous support layer>
The porous support layer is a layer that supports the separation functional layer, and can also be referred to as a porous resin layer when the resin is a material.

The material used for the porous support layer and its shape are not particularly limited, but may be formed on the substrate with a porous resin, for example. As the porous support layer, polysulfone, cellulose acetate, polyvinyl chloride, epoxy resin or a mixture of those can be used, and the chemical, mechanical and thermal stability is high, and the pore size is controlled. It is preferable to use easy polysulfone.

The porous support layer gives mechanical strength to the separation membrane. However, it does not have a separation performance like a separation membrane by itself for a component having a small molecular size such as ions. The pore size and pore distribution of the porous support layer are not particularly limited. For example, the porous support layer may have uniform and fine pores, or the side on which the separation functional layer is formed. It may have a pore size distribution such that the diameter gradually increases from the surface to the other surface. In any case, the projected area equivalent circle diameter of the pores measured using an atomic force microscope or an electron microscope on the surface on the side where the separation functional layer is formed is 1 nm or more and 100 nm or less. preferable. In particular, from the viewpoint of interfacial polymerization reactivity and retention of the separation functional layer, the pores on the surface on the side where the separation functional layer is formed in the porous support layer preferably have a projected area circle equivalent diameter of 3 to 50 nm.

The thickness of the porous support layer is not particularly limited, but is preferably in the range of 20 μm or more and 500 μm or less, more preferably 30 μm or more and 300 μm or less in order to give strength to the separation membrane.

The morphology of the porous support layer can be observed with a scanning electron microscope, a transmission electron microscope, or an atomic microscope. For example, when observing with a scanning electron microscope, after peeling off the porous support layer from the substrate, it is cut by the freeze cleaving method to obtain a sample for cross-sectional observation. This sample is coated with platinum, platinum-palladium or ruthenium tetrachloride, preferably ruthenium tetrachloride, and is observed with a high resolution field emission scanning electron microscope (UHR-FE-SEM) at an acceleration voltage of 3 to 6 kV. To do. A Hitachi S-900 electron microscope can be used as the high-resolution field emission scanning electron microscope. Based on the obtained electron micrograph, the film thickness of the porous support layer and the projected area equivalent circle diameter of the surface can be measured.

The thickness and pore diameter of the porous support layer defined here are average values, respectively. The thickness of the porous support layer is an average value of 20 points measured by cross-sectional observation in a direction orthogonal to the thickness direction, for example, at intervals of 20 μm. Moreover, a hole diameter is an average value of each projected area circle equivalent diameter measured about 200 holes.

Next, a method for forming the porous support layer will be described. For example, an N, N-dimethylformamide (hereinafter referred to as DMF) solution of the above polysulfone is cast to a predetermined thickness on a substrate (for example, a densely woven polyester nonwoven fabric) described later. It can be produced by wet coagulation in water.

The porous support layer is “Office of Saleen Water Research and Development Progress Report” No. 359 (1968). In addition, in order to obtain a desired form, the polymer concentration, the temperature of the solvent, and the poor solvent can be adjusted.

For example, a predetermined amount of polysulfone is dissolved in DMF to prepare a polysulfone resin solution having a predetermined concentration. Next, the polysulfone resin solution can be obtained by applying the polysulfone resin solution on the polyester nonwoven fabric substrate to a substantially constant thickness, removing the surface solvent in the air for a certain time, and then coagulating the polysulfone in the coagulation liquid. .

<Base material>
From the viewpoint of the strength and dimensional stability of the separation membrane, the separation membrane may have a substrate. As the substrate, it is preferable to use a fibrous substrate in terms of strength and fluid permeability.

As the substrate, a long fiber nonwoven fabric and a short fiber nonwoven fabric can be preferably used. In particular, since the long fiber nonwoven fabric is excellent in the film forming property of the porous support layer, when the polymer solution is cast, the solution penetrates through the permeation and the porous support layer peels off. In addition, it is possible to prevent the film from becoming non-uniform due to the fluffing of the base material and the occurrence of defects such as pinholes. In addition, since the base material is made of a long-fiber non-woven fabric composed of thermoplastic continuous filaments, the thickness of the porous support layer becomes uneven and the membrane is caused by fluffing of fibers during casting of a polymer solution compared to a short-fiber non-woven fabric. The occurrence of surface defects can be suppressed. Further, when the separation membrane is continuously formed, tension is applied in the film forming direction, and therefore, it is preferable to use a long fiber nonwoven fabric having excellent dimensional stability as a base material.

In the long-fiber nonwoven fabric, the fibers in the surface layer on the opposite side to the porous support layer are more vertically oriented than the fibers in the surface layer on the porous support layer side in terms of the film forming property and strength of the porous support layer. preferable. According to such a structure, the high effect which prevents a film tear etc. is implement | achieved by maintaining intensity | strength.

More specifically, the fiber orientation degree in the surface layer on the side opposite to the porous support layer of the long-fiber nonwoven fabric is preferably 0 ° to 25 °, and the fiber orientation degree in the surface layer on the porous support layer side And the orientation degree difference is preferably 10 ° to 90 °. The fiber orientation degree is an index indicating the direction of the fibers of the nonwoven fabric substrate. Specifically, it is the average value of the angle between the direction in which the porous support layer and the separation functional layer are continuously formed, that is, the longitudinal direction of the nonwoven fabric substrate and the fibers constituting the nonwoven fabric substrate. is there. That is, if the longitudinal direction of the fiber is parallel to the film forming direction, the fiber orientation degree is 0 °. If the longitudinal direction of the fiber is perpendicular to the film forming direction, that is, if it is parallel to the width direction of the nonwoven fabric substrate, the degree of orientation of the fiber is 90 °. Accordingly, the closer to 0 ° the fiber orientation, the longer the orientation, and the closer to 90 °, the lateral orientation.

The separation membrane manufacturing process and the element manufacturing process include a heating process, but a phenomenon occurs in which the porous support layer or the separation functional layer contracts due to the heating. In particular, the shrinkage is remarkable in the width direction where no tension is applied in continuous film formation. Since shrinkage causes problems in dimensional stability and the like, a substrate having a small rate of thermal dimensional change is desired. If the difference between the fiber orientation degree in the layer opposite to the porous support layer and the fiber orientation degree in the surface layer on the porous support layer side of the nonwoven fabric substrate is 10 ° to 90 °, the change in the width direction due to heat is caused. It can also be suppressed, which is preferable.

Fiber orientation can be measured as follows. First, 10 small sample samples are randomly collected from the nonwoven fabric. Next, the surface of the sample is photographed at 100 to 1000 times with a scanning electron microscope. In the photographed image, 10 samples are selected for each sample, and the angle when the longitudinal direction (longitudinal direction, film forming direction) of the nonwoven fabric is 0 ° is measured. That is, the angle is measured for a total of 100 fibers per nonwoven fabric. An average value is calculated from the angles of 100 fibers thus measured. The value obtained by rounding off the first decimal place of the obtained average value is the fiber orientation degree.

The thickness of the base material is set so that the total thickness of the base material and the porous support layer is within the range of 0.03 to 0.3 mm, and more preferably within the range of 0.05 to 0.25 mm. Is preferred.

(1-3) First Permeation Side Channel Material The membrane leaf has a first permeation side channel material. As shown in FIGS. 1 and 2, the first permeation side flow path member is disposed on the permeation surface side of the separation membrane 1. That is, the first permeation side channel material exists on the permeation side of the separation membrane so as to form a permeation side flow channel. “Provided to form a flow path on the permeate side” means that when a membrane leaf including a separation membrane is incorporated in a separation membrane element described later, the permeated fluid that has permeated the separation membrane can reach the water collecting pipe. Thus, it means that a flow path is formed in the second permeation side flow path material described later. In addition, in FIG. 1 and FIG. 2, the component 3a of the 1st permeation | transmission side channel material is shown in figure.

It is preferable that the first permeate side channel material is formed of a material different from that of the separation membrane. A different material means a material having a composition different from the material used in the separation membrane. In particular, the composition of the first permeate-side channel material is preferably different from the composition of the surface of the separation membrane on which the first permeate-side channel material is formed. It is preferable that the composition is different.

Although it does not specifically limit as a component which comprises a 1st permeation | transmission side channel material, Resin is used preferably. Specifically, from the viewpoint of chemical resistance, polyolefins such as ethylene vinyl acetate copolymer resin, polyethylene, and polypropylene, and copolymerized polyolefins are preferable, and polymers such as urethane resins and epoxy resins can be selected. It can be used as a mixture comprising two or more types. In particular, since a thermoplastic resin is easy to mold, a channel material having a uniform shape can be formed.

The first permeate-side channel material is preferably not continuous in the longitudinal direction of the water collecting pipe for the purpose of securing a permeate-side channel. “Not continuous” means that a plurality of constituent elements of the first permeate-side channel material are present at intervals. On the other hand, members such as nets, tricots, and films have an integrated and continuous shape.

In the example shown in FIG. 1, the first permeate-side channel material composed of the plurality of components 3a of the first permeate-side channel material is not continuous in the x direction (that is, the width direction). However, even if the constituent elements of the first permeate-side channel material are connected at a location far away from the water collection pipe, the permeate channel can be secured, and such an aspect is also included in the present invention. On the other hand, in the y direction (that is, the length direction), the component 3a of the first permeation side flow path member is provided so as to be continuous from one end to the other end of the separation membrane body 2. That is, when the membrane leaf 80 is incorporated in the separation membrane element as shown in FIG. 3, the component 3a of each of the first permeate-side flow path members is inside the separation membrane 2 in the winding direction (on the left side in FIG. 3). ) To the outer end (right side in FIG. 3). The inner side in the winding direction is the side close to the water collecting pipe in the separation membrane, and the outer side in the winding direction is the side far from the water collecting pipe in the separation membrane.

The shape of the component 3a of the first permeation side flow path material is not particularly limited, but a shape that reduces the flow resistance of the flow path and stabilizes the flow path when permeated can be selected. In these respects, in the cross section (xz cross section) perpendicular to the surface direction of the separation membrane, the shape of the first permeation side channel material is preferably a rectangle, trapezoid, rounded rectangle, semi-ellipse, or a combination thereof.

For example, when the xz cross-sectional shape of the component 3a of the first permeate-side channel material is trapezoidal, if the difference between the lengths of the upper base and the lower base is too large, the separation membrane becomes the first permeate-side channel during pressure filtration. The ratio of the length of the upper base to the length of the lower base is preferably 0.6 or more and 1.4 or less, and more preferably 0.8 or more and 1.2 or less in order to easily fall into the gap between the constituent elements 3a of the material. .

Although the width of the xz cross section of the component 3a of the first permeate-side channel material is preferably formed to have the same width regardless of the height from the separation membrane surface, As long as the drop of the membrane due to the gap between the constituent elements of the material does not increase, it may be formed so that the width is smaller as the distance from the separation membrane surface is higher, and conversely the width is higher as the distance is higher. You may form so that it may become large.

If the first permeate-side channel material is a thermoplastic resin, the processing temperature and the type of thermoplastic resin to be selected are changed, and the deformation of the thermoplastic resin is induced, thereby requiring the required separation characteristics and permeation performance conditions. So that the shape of the flow path material can be freely adjusted.

Further, the shape of the constituent elements of the plurality of first permeation side flow path materials observed in the y direction from the xy cross section may be, for example, linear, curvilinear, or wavy.

Moreover, when the shape which observed the component of the some 1st permeation | transmission side channel material in the y direction from the xy cross section is linear, the component of the adjacent 1st permeation | transmission side channel material is mutually substantially parallel. It may be arranged. “To be arranged substantially in parallel” means that, for example, a plurality of constituent elements of the first permeation-side channel material do not intersect on the separation membrane. Preferably, the angle formed by two adjacent first permeation-side flow path members is 0 ° or more and 30 ° or less, more preferably the angle is 0 ° or more and 15 ° or less, and further preferably the angle is 0. It is not less than 5 ° and not more than 5 °.

In addition, the angle formed by the longitudinal direction of the constituent elements of the first permeate-side channel material and the longitudinal direction of the water collecting pipe is preferably 60 ° or more and 120 ° or less, and more preferably 75 ° or more and 105 ° or less. Preferably, it is 85 ° or more and 95 ° or less. When the angle formed by the longitudinal direction of the constituent elements of the first permeate-side channel material and the longitudinal direction of the water collecting pipe is within the above range, the permeated water is efficiently collected in the water collecting pipe.

In order to ensure a stable flow path, it is possible to suppress the separation membrane from falling into the gap of the first permeate-side flow path material when the separation membrane is pressurized from the supply side surface in the separation membrane element. preferable. For this purpose, it is preferable that the contact area between the separation membrane and the channel material is large, that is, the ratio of the area of the channel material to the area of the separation membrane is large. On the other hand, in order to reduce pressure loss, it is preferable that the ratio is small.

The method for forming the first permeate-side channel material is not particularly limited, but the material constituting the first permeate-side channel material is arranged directly on the permeate side of the separation membrane by printing, spraying, applicator application, hot melt processing, etc. Is used.

If the thickness of the first permeate-side channel material is large, the flow resistance of the permeate-side channel is reduced, but the membrane area that can be wound is reduced. If it is small, the area of the membrane leaf that can be wound increases, but the flow resistance in the permeate-side channel increases. The thickness of the first permeate side channel material is preferably 50 μm or more and 800 μm or less, more preferably 100 μm or more and 400 μm or less, and further preferably 200 μm or more and 350 μm or less. Within this range, a stable permeate flow path can be secured.

The thickness of the first permeate-side channel material indicates the difference in height between the surface of the separation membrane on the base material side and the highest part of the first permeate-side channel material, and the portion impregnated in the base material The thickness of is not included.

The thickness of the first transmission side channel material can be directly measured, for example, by using a commercially available thickness measuring device, and is measured by analyzing an image taken using a scanning electron microscope or a microscope. You can also.

As shown in FIG. 1, the interval b between the constituent elements 3 a of the first permeate-side channel material corresponds to the width of the permeate-side channel 4. When the interval is large, the flow path becomes wide, and there is an advantage that the pressure loss becomes small. On the other hand, if the interval is small, there is an advantage that film drop hardly occurs. From these balances, the interval is preferably 200 to 1500 μm, and if it is within this range, the film can be prevented from falling and the pressure loss can be reduced. More preferably, it is 300 to 1000 μm, and still more preferably 400 to 800 μm.

If the width d of the component 3a of the first permeate side channel material is large, the shape of the channel material can be maintained even when pressure is applied to the first permeate side channel material during operation of the separation membrane element. The permeate side flow path is stably formed. If it is small, the width of the flow path of the permeated fluid becomes relatively large, so that the flow velocity of the permeated fluid becomes small and the flow resistance can be reduced. The width d is preferably 10 μm or more and 1000 μm or less. When the width is 1000 μm or less, a sufficient flow path on the permeation side can be secured.

The interval b between the constituent elements 3a of the first permeate-side channel material is calculated by an average value of the maximum value and the minimum value of the channel width. As shown in FIG. When the component 3a of the first permeate-side channel material has a trapezoidal shape with a thin top and a thick bottom, first, the distance between the upper ends of the two adjacent first permeate-side channel members and the lower end The distance between them is measured and the average value is calculated. It is calculated for a given number of arbitrary cross-sections and expressed as their average value.

The width d of the component 3a of the first permeate-side channel material is calculated as an average value of the maximum width and the minimum width of the component of the first permeate-side channel material. As shown in FIG. 2, when the cross section of the component 3a of the first permeate-side channel material shows a trapezoidal shape with a narrow top and a thick bottom, the width of the lower end portion of the component 3a of the first permeate-side channel material And the width of the upper end is measured, and the average value is calculated. It is calculated for a given number of arbitrary cross-sections and expressed as their average value.

The interval b and the width d of the constituent elements 3a of the first transmission side transmission side channel material can be measured by analyzing an image taken using a scanning electron microscope or a microscope.

If the projected area ratio of the first permeate side channel material to the separation membrane surface is large, the shape of the channel material can be maintained even if pressure is applied to the first permeate side channel material during operation of the separation membrane element. Although it is possible, the flow path on the permeate side becomes narrow. If it is small, a wide flow path on the permeate side can be secured, but pressure is applied during operation of the separation membrane element, so that the shape of the flow path material cannot be maintained and is easily deformed. The projected area ratio of the first permeate-side channel material to the separation membrane surface is preferably 0.3 to 0.7, more preferably 0.4 to 0.6. If it is this range, the deformation | transformation of the 1st permeation | transmission side channel material can be suppressed, and the permeation | transmission side flow path can be ensured.

The projected area ratio of the first permeate-side channel material to the separation membrane surface can be calculated from the interval b and the width d of the component 3a of the first permeate-side channel material (see FIG. 1). That is, the projected area ratio of the upper end portion of the flow path material is calculated by (width d of the upper end portion of the flow path material) / ((width d of the upper end portion of the flow path material) + (interval b of the upper end portion of the flow path material)). , (The width d of the lower end portion of the channel material) / ((the width d of the lower end portion of the channel material) + (the interval b of the lower end portion of the channel material)), the projected area ratio of the lower end portion of the channel material is calculated, The projected area ratio of the first permeate-side channel material to the separation membrane surface is expressed by the average value thereof.

As described above, the components of the first permeate-side channel material are provided substantially parallel to the length direction. In the case where the constituent elements of the first permeate-side flow path material are provided substantially parallel to the length direction, the adjacent first permeation can be achieved if the width d of the constituent elements of the first permeate-side flow path material is increased. If the distance b between the components of the side channel material is reduced and the width d of the channel material 3 is reduced, the width d of the adjacent channel material 3 is increased. That is, if the width d of the flow path material 3 is reduced and the distance b between the adjacent flow path materials 3 is increased, the flow path is increased and the flow resistance is reduced, but the shape retention of the separation membrane against pressure is reduced. .

When the first permeate-side flow path material provided on the permeate side is incorporated into the separation membrane element, the permeate-side flow path is connected from one end of the separation membrane to obtain a good recovery rate of the permeate fluid. It may be provided so as to be continuous up to the end. As an example of such a configuration, the flow path 4 is continuously formed in the length direction as shown in FIG. Such a flow path is formed by a plurality of first transmission side flow path materials being discontinuously present in the width direction (x direction).

The first permeation side flow path material may be directly on the permeation side surface of the separation membrane main body, or the sheet provided with the first permeation side flow path material may be on the permeation side surface of the separation membrane. As the sheet, for example, a nonwoven fabric can be used.

If a knitted fabric such as a conventional tricot is used as a permeate-side channel material in the membrane leaf adjacent to the separation membrane, the entire thickness cannot be used as a groove. In the first permeation-side channel material of the present invention, all the height differences of the first permeation-side channel material 3 can be utilized as a channel groove. Therefore, the thickness of the tricot and the thickness of the first permeation-side channel material 3 are the same. Is the same, the flow path in the thickness direction becomes wider and the pressure loss becomes smaller, so the amount of water produced by the separation membrane element increases. Even when the first permeation side flow path material 3 is formed on a sheet-like material such as a non-woven fabric, the same effect can be obtained by reducing the thickness of the sheet as much as possible.

A part of the components of the first permeation side channel material may be impregnated in the separation membrane, more specifically in the base material in the separation membrane. When the separation membrane has a substrate, a porous support layer, and a separation functional layer, it is usual to provide the first permeation side flow path material on the substrate side. Then, the impregnation of a part of the material of the first permeate-side channel material proceeds from one surface of the separation membrane to the surface in the opposite direction. When the degree of impregnation is high, the adhesion between the first permeation side flow path material and the separation membrane becomes strong, and the first permeation side flow path material is difficult to peel off from the separation membrane even if pressure filtration is performed. When the first permeation side flow path material is peeled from the separation membrane, it becomes difficult to secure a desired permeation side flow path.

However, if the component of the first permeation side flow path material penetrates the separation membrane and is impregnated to the vicinity of the separation functional layer, the material of the first permeation side flow path material destroys the separation functional layer when pressurized. There are things to do. Therefore, when the separation membrane is impregnated with the component of the first permeation side channel material, the ratio of the thickness of the channel material to the thickness of the base material (that is, the impregnation rate) is in the range of 5 to 95%. Is preferably in the range of 10 to 80%, more preferably in the range of 20 to 60%. In addition, impregnation thickness means the maximum value of the thickness of the part impregnated with the material of one 1st permeation | transmission side channel material, when one cross section is observed.

The impregnation thickness of the material of the first permeation side channel material can be adjusted, for example, by changing the type of the material (more specifically, the type of resin) and / or the amount of the material.

In addition, by subjecting the base material impregnated with the material of the first permeation side flow path material to thermal analysis such as differential scanning calorimetry, a peak due to the component of the first permeation side flow path material is separated from the base material. If it is obtained, it can be confirmed that the first permeation-side channel material is impregnated in the base material.

The impregnation ratio of the first permeation side flow path material 3 is determined by observing the cross section of the separation membrane where the first permeation side flow path material 3 exists with a scanning electron microscope, a transmission electron microscope, or an atomic force microscope. The impregnation thickness of the material 3 and the substrate thickness can be calculated. For example, when observing with a scanning electron microscope, the separation membrane is cut in the depth direction together with the first permeation side channel material, and the cross section is observed with a scanning electron microscope to measure the impregnation thickness and the substrate thickness. And it can calculate from the ratio of the maximum impregnation thickness which the flow-path material has most impregnated with the base material, and the base material thickness. The “base material thickness” when calculating the impregnation depth is the thickness of the base material corresponding to the portion where the maximum impregnation thickness is measured. The first permeate side channel material may not reach the edge of the separation membrane. For example, at the outer end of the membrane leaf in the winding direction and the end of the permeate side membrane leaf in the longitudinal direction of the water collecting pipe, The material may not be provided.

(1-4) Supply Side Channel Material As shown in FIG. 4, the membrane leaf has a supply side channel material 6 on the supply side of the separation membrane 1 (a). The supply-side channel material 6 may be formed so as to form a channel for supplying the raw fluid to the separation membrane. Furthermore, in order to suppress the concentration polarization of the raw fluid, it is preferable to have a shape that disturbs the flow of the raw fluid.

The supply-side channel material may be a member having a continuous shape such as a film or a net, or a discontinuous shape showing a projected area ratio that is greater than 0 and less than 1 with respect to the separation membrane. You may have. Further, the supply-side channel material may be separable from the separation membrane or may be joined to the separation membrane.

The material of the supply side channel material is not particularly limited, and may be the same material as the separation membrane or a different material.

In the supply side flow path, it is important to form the flow path stably, but it is also important to reduce the pressure loss because the passing fluid is more than the permeate side flow path. Therefore, the projected area ratio of the supply-side channel material is preferably 0.03 to 0.5, more preferably 0.1 to 0.4, and still more preferably 0.15 to 0.35.

The projected area ratio of the supply-side channel material can be calculated by analyzing an image obtained by photographing the supply-side channel material with a microscope or the like from a direction perpendicular to the surface of the supply-side channel material.

When the thickness of the supply-side channel material is large, the pressure loss is reduced, but when the element is made into an element, the membrane area that can be filled in the vessel is reduced. If the thickness is small, the pressure loss of the flow path will increase, and the separation characteristics and water permeation performance will deteriorate. Therefore, the fresh water generation capacity of the element is reduced, and the operation cost for increasing the fresh water generation amount is increased. Therefore, in consideration of the balance between the above-mentioned performances and the operation cost, the thickness of the supply side channel material may be 80 to 2000 μm, preferably 200 to 1000 μm.

The thickness of the supply-side channel material can be directly measured by a commercially available thickness measuring instrument, or can be measured by analyzing an image taken using a microscope.

When the supply-side channel material has a discontinuous shape, the groove width is preferably 0.2 mm or more and 10 mm or less, more preferably 0.5 mm, for the same reason as in the case of the first permeation-side channel material described above. The pitch is preferably 3 mm or less, and the pitch is suitably designed between 1/10 times and 50 times or less of the groove width. The groove width is the part that sinks on the surface where the height difference exists, and the pitch is the horizontal from the highest point of the high part to the highest part of the adjacent high part on the surface where the height difference exists. It is distance [2. Separation membrane element)
(2-1) Overview As shown in FIG. 3, the separation membrane element 100 includes the water collecting pipe 9 and any of the above-described configurations, and includes a membrane leaf 80 wound around the water collecting pipe 9. In FIG. 3, a part of the membrane leaf is expanded. In addition, the separation membrane element can further include a member such as an end plate (not shown) if necessary.

(2-2) Membrane leaf The membrane leaf includes a separation membrane having a supply-side surface and a permeation-side surface, a supply-side channel material on the supply-side surface, and a permeation side on the permeation-side surface. Channel material.

Here, the structure of the membrane leaf will be described with reference to FIG. The second permeation side channel material is not shown in the membrane leaf of FIG. In FIG. 4, the separation membrane 1 (b), the plurality of first permeation-side channel material components 3 a, the separation membrane 1 (a), the supply-side channel material, and the separation membrane 1 (c) are arranged in order from the top. Yes. Here, the assembly of the constituent elements 3a of the first permeate-side flow path material becomes the first permeate-side flow path material. Reference numerals 11 (b), 11 (a), and 11 (c) denote surfaces on the supply side in each separation membrane. Reference numerals 12 (b), 12 (a), and 12 (c) are permeation side surfaces of the separation membranes.

The fluid coming from the supply side channel must flow out to the permeate side channel through the separation membrane. Therefore, the side on the side of the water collection pipe is not sealed between the separation membrane 1 (b) and the separation membrane 1 (a) so that the permeate flows into the second permeation side flow path and the water collection pipe. 3 sides are sealed. As a result, it becomes an envelope shape. On the other hand, in order to prevent the raw fluid from directly flowing out to the water collecting pipe side, the sides of the water collecting pipe side of the separation membrane 1 (a) and the separation membrane 1 (c) are sealed.
Examples of the sealing means include a form bonded by an adhesive, hot melt, etc., a form fused by heating or laser, and a form in which a rubber sheet is sandwiched. Sealing by adhesion is particularly preferable because it is the simplest and most effective.

The membrane leaf is wound around the water collecting pipe, and is arranged so that the width direction is along the longitudinal direction (x direction) of the water collecting pipe 9. As a result, the membrane leaf is arranged such that the length direction is along the winding direction.

Note that adjacent separation membranes may have the same configuration or different configurations. That is, if at least one of the two facing separation membranes is provided with the above-described first permeation-side flow path material, the permeation-side flow path can be secured, so the first permeation-side flow path material is bonded. The separation membranes that are provided and the separation membranes that are not provided may be alternately stacked.

(2-3) Water Collection Pipe In FIG. 3, the water collection pipe 9 may be configured so that permeated water flows therethrough, and the material, shape, size, and the like are not particularly limited. As the water collection pipe 9, for example, a cylindrical member having a side surface provided with a plurality of holes is used.

(2-4) Second Permeation Side Channel Material The second permeation side channel material of the present invention is present at the end of the membrane leaf. The permeate channel is formed by a first permeate channel material on the separation membrane and a second permeate channel material at the end of the membrane leaf. The second permeate side channel material is a sheet-like member. Due to the presence of the second permeate side channel material, a permeate channel is stably formed on the outer periphery of the water collecting pipe. In addition, the 2nd permeation | transmission side channel material is wound around the water collection pipe over 1 round.

The length of the second permeate-side channel material that is wound around the water collection pipe is only required to allow a permeate flow path to be formed around the water collection pipe, and is equivalent to two or more rounds. It is preferable that the length corresponds to three or more rounds, and it is more preferable that the length corresponds to four or more rounds. The second permeate channel material is at least in contact with the first permeate channel material at the end of the first permeate channel material to form a permeate channel. Furthermore, you may overlap in the edge part of the 1st permeation | transmission side channel material.

5 to 8 show configuration examples of the separation membrane element of the present invention. In the separation membrane element shown in these drawings, the separation membrane 1, the supply-side flow path material 6, and the first permeation-side flow path material 3 are not yet wound. The membrane leafs of FIGS. 5 to 8 are arranged so that the permeate-side flow path is directed toward the water collection pipe 9, that is, located inside the winding. Moreover, in the separation membrane element shown in these drawings, the first permeation side flow path member 1 is connected to the second permeation side flow path member 5 at the permeation side surface. As a result, the permeation side flow path formed by the first permeation side flow path material is connected to the flow path formed around the water collection pipe 9 by the flow path of the second permeation side flow path material 5. Furthermore, it is preferable that the 2nd permeation | transmission side channel material winds the outer peripheral surface of a water collection pipe over at least 1 round. Moreover, it is preferable that a part of 2nd permeation | transmission side flow path material has overlapped with a 1st permeation | transmission side flow path material and a part of 1st permeation | transmission side flow path material.

In the form shown in FIG. 5, the second permeation side flow path member 5 is in contact with each of the plurality of first permeation side flow path members 3 at the end portions.

In the form of FIG. 5, the number of the second permeation side flow path material is one, but a plurality of the second permeation side flow path materials may be provided instead. In order to maintain the contact between the second permeation side channel material and the first permeation side channel material, it is preferable to bond both. In view of its ease of manufacture, in all aspects of the present invention, the number of second permeation side flow path members is preferably 1 to 5, more preferably 1 to 3, and even more preferably 1. Further, in FIG. 5, the second flow path side permeation material is in contact with all of the plurality of first permeation side flow path materials at the end, but in the present invention, it is in contact with all the first permeation side flow path materials. There is no need.
In the form shown in FIG. 6, there are a plurality of second permeation-side flow path members 5 wound around the water collection pipe 9, each of which includes a separation membrane 1, a first permeation-side flow path member, and a supply-side flow path member 6. Located at the bottom of When the membrane leaf is further wound from the state of FIG. 6, among the plurality of first permeation side flow path materials, the second permeation side flow path material and the first permeation side flow path material 3 at the top in FIG. Will be in contact.

In the form shown in FIG. 7, the second permeation side flow path member 5 overlaps the plurality of first permeation side flow path members 3.

In the form shown in FIG. 8, the second permeation side flow path member 5 partially overlaps the plurality of first permeation side flow path members. *

As the second permeate-side channel material, a sheet-like material having a continuous shape such as a net, tricot, nonwoven fabric, film, or a sheet-like material in which discontinuous protrusions are formed on these sheet-like materials is used. . If these sheet-like materials are used, a bundle of membrane leaves can be easily wound around the water collecting pipe. In addition, the second permeation side flow path material overlaps at least the tip opening of the first permeation side flow path material, so that the first permeation side flow path material is peeled from the separation membrane main body at the opening of the permeation side membrane leaf. In addition, it is possible to suppress the membrane drop during the pressurizing operation of the separation membrane element.

Although the pressure loss can be reduced if the porosity of the second permeation side channel material is large, the separation membrane tends to fall into the permeation side channel material during pressurization. If the porosity is small, the pressure loss increases, but the drop of the separation membrane during pressurization can be suppressed, but the pressure loss increases. The porosity of the second permeation side channel material is preferably 30 to 80%, more preferably 40 to 80%, and further 50 to 65%. If it is these ranges, a pressure loss can be made small and the fall of a separation membrane can be suppressed.

The porosity of the second permeation side channel material can be calculated from the specific gravity of the resin used and the thickness of the second permeation side channel material by measuring the mass per unit area.

Although the pressure loss can be reduced if the thickness of the second permeate-side channel material is large, the membrane area that can be filled in the container of the separation membrane element is reduced. If it is thin, the membrane area that can be filled in the separation membrane element increases, but the pressure loss increases. The thickness of the second permeation side channel material is preferably 0.01 mm to 0.4 mm, more preferably 0.04 mm or more and 0.15 mm or less, and on the other hand 0.35 mm or less.

The thickness of the second permeate side channel material can be measured directly with a commercially available thickness measuring instrument, or otherwise observed from a direction perpendicular to the surface of the second permeate side channel material with a commercially available microscope. It can also be measured by analyzing the photographed image.

When the first permeate side channel material and the second permeate side channel material overlap as shown in FIGS. 6 to 8, if the sum of the thicknesses of the first permeate side channel material and the second permeate side channel material is large, Although the pressure loss can be reduced, the membrane area that can be filled in the separation membrane element is reduced. If it is small, the membrane area that can be filled in the separation membrane element increases, but the pressure loss increases. Therefore, it is preferable that the sum of the thicknesses of the first permeate side channel material and the second permeate side channel material is 0.1 mm or greater and 0.6 mm or less.

If the apparent density of the second permeate side channel material is large, the pressure loss increases, but the rigidity of the second permeate side channel material can be increased, so that it is easy to wind a plurality of separation membrane leaf bundles. Can be improved. If it is small, the pressure loss is small, but the rigidity of the second permeate-side channel material is small, so the effect of improving the ease of winding the separation membrane leaf bundle is small. The density of the second permeation side channel material is preferably 0.3 g / cm ³ or more and 1.2 g / cm ³ or less.

The apparent density of the second permeation side channel material can be calculated by measuring the mass per unit area of the second permeation side channel material and dividing by the thickness.

The material of the second permeate-side channel material may be any material that can be easily wound around the water collecting pipe, and is preferably different from the separation membrane. The compression modulus of the second permeation side channel material is preferably 0.1 GPa to 5 GPa. If the elastic modulus is within this range, the second permeate-side channel material can be easily wound around the water collection pipe, and the first permeate-side channel material can be effectively peeled off from the separation membrane body. Can be suppressed. Specifically, polyester, polyethylene, polypropylene, or the like is preferably used as the material for the second permeation side channel material.

The elastic modulus of the second permeation side channel material can be measured, for example, by performing a compression test using an autograph and creating a stress strain diagram.

[3. Method for manufacturing separation membrane element]
A conventional element manufacturing apparatus can be used for manufacturing the separation membrane element. Further, as a method for producing the element, a method described in a reference document (Japanese Patent Laid-Open No. 11-226366) can be used. Details are as follows.

(3-1) Production of Separation Membrane Body The method for producing the separation membrane body has been described above, but a brief summary is as follows.

Resin is dissolved in a good solvent, and the resulting resin solution is cast on a substrate and immersed in pure water to combine the porous support layer and the substrate. Thereafter, as described above, a separation functional layer is formed on the porous support layer. Furthermore, chemical treatment such as chlorine, acid, alkali, nitrous acid, etc. is performed to enhance separation performance and permeation performance as necessary, and the monomer is washed to produce a continuous sheet of the separation membrane body.

(3-2) Arrangement of supply-side channel material When the supply-side channel material is a member having a continuous shape such as a net, the supply side channel material is overlapped with the separation membrane and the supply-side channel material. A flow path can be formed.

In addition, by directly applying the resin to the separation membrane, a supply-side channel material having a discontinuous or continuous shape can be formed. Even when the supply-side channel material is fixed to the separation membrane, the arrangement of the supply-side channel material may be regarded as a part of the method of manufacturing the separation membrane.

Further, the flow path may be formed by processing the separation membrane with unevenness. Examples of the uneven processing method include methods such as embossing, hydraulic forming, and calendering. The embossing conditions, the embossed shape, and the like can be changed according to the required performance of the separation membrane element. This uneven processing may be regarded as a part of the method for manufacturing the separation membrane.

(3-3) Formation of Permeate-side Channel As described above, the permeate-side channel is composed of the first permeate-side channel material and the collector provided on the separation membrane main body or on a sheet-like material different from the separation membrane main body. It is formed by the 2nd permeation | transmission side channel material wound around the outer peripheral surface of a water pipe. The first permeate side channel material may be provided on a sheet-like material different from the separation membrane main body.

The method for disposing the first permeate-side channel material is not particularly limited, but a roll type coater, a nozzle type hot melt applicator, a spray type hot melt applicator, a flat nozzle type hot melt applicator, a gravure method, an extrusion type coater, Printing, spraying, etc. can be used.

The second permeate-side channel material is adhered to the water collecting pipe by tape or welding, and is further adhered to the membrane leaf by welding.

(3-4) Lamination and winding of separation membrane As described in the section “(2-2) Membrane leaf” above, the separation membrane so that the permeate flows to the second permeate side flow path and the water collecting pipe. Between 1 (b) and separation membrane 1 (a), the side on the water collecting pipe side is not sealed, and the remaining three sides are sealed to form an envelope.
Sealing can be performed by bonding with an adhesive or hot melt, or by fusion with heat or laser. The adhesive used for sealing preferably has a viscosity in the range of 40 ps to 150 ps, and more preferably 50 ps to 120 ps. When wrinkles occur in the separation membrane, the performance of the separation membrane element may deteriorate, but when the adhesive viscosity is 150 ps or less, wrinkles are less likely to occur when the separation membrane is wound around a water collection pipe. . Moreover, when the adhesive viscosity is 40 ps or more, the outflow of the adhesive from between the separation membranes is suppressed, and the risk that the adhesive adheres to unnecessary portions is reduced.

The amount of the adhesive applied is preferably such that the width of the portion to which the adhesive is applied after the separation membrane is wound around the water collecting pipe is 10 mm or more and 100 mm or less. As a result, the separation membrane is securely bonded, and the inflow of the raw fluid to the permeate side is suppressed. Also, a relatively large effective membrane area can be secured.

The adhesive is preferably a urethane-based adhesive, and in order to make the viscosity in the range of 40 ps to 150 ps, the main component isocyanate and the curing agent polyol are mixed in a ratio of isocyanate: polyol = 1: 1 to 1: 5. The ones made are preferred. The viscosity of the adhesive is measured with a B-type viscometer (JIS K 6833) based on the viscosity of a mixture in which the main agent, the curing agent alone, and the blending ratio are defined in advance.

In addition, the second permeation side channel material is substantially bonded to the first permeation side channel material and the second permeation by, for example, bonding the second permeation side channel material to the corner of the separation membrane by thermal fusion. A side channel material can be connected.

Thus, the membrane leaf is wound around the water collecting pipe after the adhesive is applied. Thus, the membrane leaf is wound in a spiral shape.

In the present invention, the permeate side channel material includes both the first permeate side channel material and the second permeate side channel material. The first permeate-side channel material can secure a wide permeate-side channel in the separation membrane leaf, and can reduce pressure loss. On the other hand, the second permeate-side flow path material can secure a flow path from the opening end on the permeate side of the separation membrane leaf to the hole on the surface of the water collection pipe, so that pressure loss near the water collection pipe can be reduced. . Therefore, the pressure loss of the entire permeation-side flow path can be reduced by connecting both the first permeation-side flow path material and the second permeation-side flow path material.
In addition, by overlapping the second permeate side channel material on the first permeate side channel material, the first permeate side channel material is separated from the separation membrane or pressurized to the permeation side channel by the separation membrane. Depression can be suppressed.

(3-5) Other steps The method of manufacturing a separation membrane element may include further winding a film, a filament, and the like around the wound body of the separation membrane formed as described above. Further steps such as edge cutting for aligning the end of the separation membrane in the longitudinal direction of the water collecting pipe, attachment of an end plate, and the like may be included.

4). Use of Separation Membrane Element The raw fluid supplied to the separation membrane element is supplied to the supply-side surface 21 of the separation membrane 1. When a part of the raw fluid permeates the separation membrane 1, the raw fluid is separated into a permeated fluid and a concentrated fluid. The permeated fluid flows inside the envelope membrane, that is, between the permeate side surfaces of the two facing separation membranes, and reaches the water collecting pipe. The permeated fluid that has flowed through the water collection pipe is discharged from the end of the water collection pipe 9 to the outside of the separation membrane element. The concentrated fluid flows between the two supply-side surfaces 21 facing each other and flows out from the end of the separation membrane element.

The separation membrane element can be used as a separation membrane module by being connected in series or in parallel and housed in a pressure vessel.

Also, the separation membrane element and module described above can be combined with a pump for supplying fluid to them, a device for pretreating the fluid, and the like to constitute a fluid separation device. By using this separation device, for example, raw water can be separated into permeated water such as drinking water and concentrated water that has not permeated through the membrane, and water suitable for the purpose can be obtained.

The higher the operating pressure of the fluid separator, the better the salt removal, but the energy required for operation also increases, and considering the durability of the composite semipermeable membrane, water to be treated is added to the composite semipermeable membrane. The operating pressure at the time of permeation is preferably 0.2 MPa or more and 10 MPa or less. The operating pressure is a so-called transmembrane pressure. As the feed water temperature increases, the salt removability decreases, but as it decreases, the membrane permeation flux also decreases. Therefore, it is preferably 5 ° C. or higher and 45 ° C. or lower. In addition, when the pH of the feed water becomes high, scales such as magnesium may be generated in the case of feed water with a high salt concentration such as seawater, and there is a concern about deterioration of the membrane due to high pH operation. Is preferred.

Examples of raw water treated by the composite semipermeable membrane include liquid mixtures containing 500 mg / L to 100 g / L TDS (Total Dissolved Solids) such as seawater, brine, and drainage. Generally, TDS refers to the total amount of dissolved solids and is expressed as “mass / volume”, or expressed as “mass ratio” by regarding 1 L as 1 kg. According to the definition, the solution filtered through a 0.45 micron filter can be calculated from the mass of the residue by evaporating at a temperature of 39.5 to 40.5 ° C., but more simply converted from practical salt content.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

(Thickness of the first permeate side channel material)
Using a scanning electron microscope (S-800) (manufactured by Hitachi, Ltd.), with respect to the cross section of any 20 first permeation-side flow path materials uniformly in the separation membrane width direction, the separation membrane length direction is evenly 20 An arbitrary cross section of the part was photographed at a magnification of 500 times. The thickness was measured by analyzing the photographed image and represented by the average value of the measurement points.

(Width and spacing of the first permeate side channel material)
Using a scanning electron microscope (S-800) (manufactured by Hitachi, Ltd.), with respect to the cross section of any 20 first permeation-side flow path materials uniformly in the separation membrane width direction, the separation membrane length direction is evenly 20 An arbitrary cross section of the part was photographed at a magnification of 500 times. By analyzing the photographed image, the width and interval of the upper end portion and the width and interval of the lower end portion of the first transmission side channel material were measured, and the average value of the measurement locations was calculated. By calculating the average value of the upper end portion and the lower end portion for both the width and the interval, the width and interval of the first permeation-side channel material were expressed.

(Projected area ratio of the first permeate side channel material)
Regarding the width and interval of the first permeation-side channel material measured as described above, the projection of the channel material upper end portion at (upper end width) / ((upper end width) + (upper end interval)). Calculate the area ratio, calculate the projected area ratio of the lower end of the channel material by (width of the lower end) / ((width of the lower end) + (interval of the lower end)), and the average value thereof, The projected area ratio of the first permeate-side channel material to the separation membrane surface is shown.

(Thickness of second permeate side channel material)
Using commercially available thickness measuring instruments, the thicknesses of 30 locations randomly selected from the second permeate side channel material were measured.

(Porosity of second permeate side channel material)
The weight of 10 samples of the second permeation-side channel material cut into a width of 20 cm and a length of 20 cm was measured, and a value obtained by converting the average value per 1 cm 2 was defined as a basis weight (g / cm 2). The porosity was calculated by the following formula. Porosity (%) = 100 × (1−weight per unit area / specific gravity / thickness)
(Density of second permeate side channel material)
The density (g / cm ³ ) of the second transmission side channel material was calculated by dividing the basis weight of the second transmission side channel material by the thickness of the second transmission side channel material.

(Number of strips at the tip of the first permeate side channel material)
The number of peeled ends of the first permeate-side channel material is the first permeate side per membrane leaf obtained by dismantling and collecting the separation membrane element after 3000 cycles of 1-minute operation and 1-minute stop cycle The number of strips at the tip of the channel material was counted.

(Membrane sagging ratio)
Membrane sacrificing ratio is determined by disassembling the separation membrane element after 3000 cycles of 1-minute operation and 1-minute stop, and the membrane bends into the permeate-side flow path, thereby blocking the permeate-side flow path. The maximum height of the portion was measured using a microscope at 10 points in the width direction and 5 points in the length direction, for a total of 50 points, and the average value was taken as the film sagging amount. The film sagging amount was shown as a ratio when the film sagging amount when only the first permeation side channel material was used as the permeation side channel material was 100. That is, the smaller the film sagging amount ratio, the smaller the film sagging, which is preferable.

(Water production)
One day obtained by one separation membrane element when operating under conditions of an operating pressure of 1.55 MPa and an operating temperature of 25 ° C. using saline with a concentration of 2000 mg / L and pH 6.5 as the feed water The permeated water amount was expressed as a water production amount (m ³ / day).

(Desalination rate (TDS removal rate))
The electric conductivity of the permeated water obtained by the same operation as that for measuring the amount of water produced was measured, and the TDS concentration was calculated. The TDS removal rate was calculated by applying the TDS concentration of the permeated water and the TDS concentration of the feed water to the following equation.
TDS removal rate (%) = 100 × {1− (TDS concentration in permeated water / TDS concentration in feed water)}
(Example 1)
A nonwoven fabric obtained from polyethylene terephthalate fiber by a papermaking method was prepared as a support film. This nonwoven fabric has a fiber diameter of about 1 dtex, a nonwoven fabric thickness of 90 μm, an air permeability (according to JISL 1096) of 1 cc / cm ² / sec, and a fiber orientation of 40 ° in the surface layer on the porous support layer side. The surface layer on the side opposite to the porous support layer is 20 °. A 15.5% by mass DMF solution of polysulfone was cast at room temperature (25 ° C.) with a thickness of 180 μm, and immediately immersed in pure water and left for 5 minutes to reinforce with a polyester fiber with a thickness of 135 μm. A roll made of the reinforced polysulfone support membrane was prepared.

Thereafter, the support membrane was unwound from the roll, a 4.2% by mass aqueous solution of m-phenylenediamine was applied to the polysulfone side surface of the support membrane, and nitrogen was blown from an air nozzle to remove excess aqueous solution from the surface of the support membrane. Thereafter, an n-decane solution at 25 ° C. containing 0.16% by mass of trimesic acid chloride was applied so that the surface was completely wetted. Thereafter, excess solution was removed from the membrane by air blowing, washed with hot water at 80 ° C., and drained by air blowing to obtain a separation membrane.

Next, application and non-application of the first permeate-side channel material were repeated on the permeation side surface of the separation membrane every 0.85 m in the length direction (y direction). In the case of application, a saponified ethylene vinyl acetate copolymer resin (trade name: “Mersen” (registered trademark) 6822X, manufactured by Tosoh Corporation) was loaded with comb-shaped shims each having a groove width and a line width of 0.38 mm. Using a hot melt applicator, it was applied to the permeation side surface of the separation membrane every 0.85 m in length at a resin temperature of 160 ° C. and a running speed of 3 m / min. A first permeate-side flow path material having a trapezoidal cross section of each component observed from the longitudinal direction of the water collecting pipe and a thickness of 0.26 mm was obtained.

Next, the separation membrane provided with the first permeate-side flow path material is cut into 26 sheets having a length of 1.7 m and a width of 0.93 m so that the effective membrane area of the spiral separation membrane element is 37 m ^2. processed. That is, the first permeation side flow path member is provided on the half of the permeation side surface of the cut separation membrane, and the first permeation side flow path material is absent on the other half.

Then, the separation membrane is folded so that the supply-side surfaces face each other, and further the separation membrane is folded using the net (thickness: 0.8 mm, pitch: 5 mm × 5 mm, fiber diameter: 0.38 mm) as the supply-side flow path material. Between them. Hereinafter, this structure is referred to as “separation membrane leaf”.

One sheet of second permeation side channel material (tricot. Thickness: 0.26 mm, groove width: 0.2 mm, ridge width: 0.3 mm, groove depth: 0.105 mm, porosity: 0.5) ABS It is fixed to a water collecting pipe (width: 1020 mm, diameter: 30 mm, number of holes 40 × 1 linear line) with double-sided tape, and 26 membrane leaves are made up of the first permeation side channel material as shown in FIG. The inner ends of the winding direction were bonded by heat fusion so as to be connected to the second permeation side flow path member, and they were wound around the water collecting pipe. Furthermore, after winding a film around the outer periphery and fixing it with tape, an edge cut, end plate attachment, and filament winding were performed to produce an 8-inch diameter element.

When this element was put in a pressure vessel and operated under the above-mentioned conditions, the amount of water produced and the desalting rate were as shown in Table 1. The recovery rate of the above operation ((fresh water production) / (raw fluid supply flow rate) × 100) was 15%.

Tables 1 and 2 below collectively show the element configurations and element performances of the examples and comparative examples.

(Example 2)
Except for using a tricot having a thickness of 0.4 mm, a groove width: 0.2 mm, a ridge width: 0.3 mm, a groove depth: 0.16 mm, and a porosity: 0.4 as the second permeation side channel material. In the same manner as in Example 1, the separation membrane element was produced and operated as shown in FIG. The amount of water produced and the desalting rate were as shown in Table 1.

(Example 3)
The separation membrane element as shown in FIG. 5 was used in the same manner as in Example 1 except that a net having a thickness of 0.4 mm, a pitch of 4 mm × 4 mm, and a porosity of 0.85 was used as the second permeation side channel material. Production and operation were performed. The amount of water produced and the desalting rate were as shown in Table 1.

Example 4
Except for using a tricot having a thickness of 0.42 mm, a groove width: 0.2 mm, a ridge width: 0.3 mm, a groove depth: 0.17 mm, and a void ratio: 0.4 as the second permeation side channel material. In the same manner as in Example 1, the separation membrane element was produced and operated as shown in FIG. The amount of water produced and the desalting rate were as shown in Table 1.

(Example 5)
A separation membrane leaf was prepared in the same manner as in Example 1, and a single tricot (thickness: 0.26 mm, groove width: 0.2 mm, ridge width: 0.3 mm, groove depth) was used as the second permeation-side channel material. : 0.105 mm, porosity: 0.5), and after winding around a water collecting pipe as shown in FIG. 6, the first permeate side channel material is used as the permeate side channel material of a bundle of membrane leaves. Piled up. For the other membrane leaves, only the first permeate side channel material is the permeate side channel material. A separation membrane element was thus produced and operated. The amount of water produced and the desalting rate were as shown in Table 1.

(Example 6)
A separation membrane was prepared in the same manner as in Example 1, and 26 separation membrane leaves were prepared in the same manner as in Example 1 except that the height of the first permeate-side channel material was changed to 0.22 mm. As the second permeate side channel material, a polyester long fiber nonwoven fabric having a porosity of 0.6, an apparent density of 0.6 g / cm ³ , and a thickness of 0.04 mm is used, and the second permeate side channel material is disposed around the water collecting pipe. Wound 10 times, and arrange the second permeate side channel material so as to overlap the entire first permeate side channel material in each separation membrane leaf as shown in FIG. Went. The amount of water produced and the desalting rate were as shown in Table 1.

(Example 7)
The height of the first permeate side channel material was changed to 0.18 mm, the porosity of the second permeate side channel material was changed to 0.13, the density was changed to 1.3 g / cm ³ , and the thickness was changed to 0.08 mm. Except for the above, a separation membrane element was produced as shown in FIG. The amount of water produced and the desalting rate were as shown in Table 1.

(Example 8)
The height of the first permeate side channel material was changed to 0.16 mm, the porosity of the second permeate side channel material was changed to 0.85, the density was changed to 0.2 g / cm ³ , and the thickness was changed to 0.1 mm. Except for the above, a separation membrane element was produced as shown in FIG. The amount of water produced and the desalting rate were as shown in Table 1.

Example 9
As in the case of Example 5, as in the case of Example 5, except that a polyester permeation nonwoven fabric having a porosity of 0.8, a density of 0.3 g / cm ³ , and a thickness of 0.1 mm was used as the second permeation side channel material. A separation membrane element was produced and operated. The amount of water produced and the desalting rate were as shown in Table 2.

(Example 10)
The height of the first permeation side flow path material is changed to 0.26 mm, and the second permeation side flow path material is provided only on the inner tip portion 5 cm of the first permeation side separation material in each separation membrane leaf as shown in FIG. A separation membrane element was produced and operated in the same manner as in Example 8 except that it was changed so as to overlap. The amount of water produced and the desalting rate were as shown in Table 2.

(Example 11)
A separation membrane leaf was prepared in the same manner as in Example 1, and a polyester long fiber nonwoven fabric having a porosity of 0.8, a density of 0.3 g / cm ³ , and a thickness of 0.1 mm was used as the second permeation side flow path material. Five second permeation side flow path members are bonded to one second permeation side flow path material to obtain a total of six second permeation side flow path materials, and one second permeation side flow path material is a collecting pipe. Then, the six second permeate side channel members are used as permeate side channel members in a total of six bundles of separation membrane leaves, and the first permeate side channel member Piled up. That is, among the 26 bundles of separation membrane leaves, there are 6 separation membrane leaves having both the first permeation side flow path material and the second permeation side flow path material, and the separation having only the first permeation side flow path material. There are 20 membrane leaves. A separation membrane element was thus produced and operated. The amount of water produced and the desalting rate were as shown in Table 2.

Example 12
A separation membrane leaf was prepared in the same manner as in Example 11, and the same second permeate side channel material as in Example 11 was used, and 13 second permeate side channel materials were added to one second permeate side channel material. Are bonded to form a total of 14 second permeate-side flow path members, and after winding one second permeate-side flow path member around the water collecting pipe for 10 turns, a total of 14 bundles of the permeate side in the membrane leaf As the channel material, the first permeate side channel material was overlaid. For the other 12 bundles of membrane leaves, only the first permeate channel material is the permeate channel material. A separation membrane element was thus produced and operated. The amount of water produced and the desalting rate were as shown in Table 2.

(Example 13)
A separation membrane element as shown in FIG. 8 was prepared in the same manner as in Example 10 except that a tricot having a thickness of 0.2 mm, a porosity of 50%, and a density of 0.4 g / cm ³ was used as the second permeation side channel material. , Drove. The amount of water produced and the desalting rate were as shown in Table 2.

(Comparative Example 1)
A tricot (thickness: 0.26 mm, groove width: 0.2 mm, ridge width: 0.3 mm, groove depth: 0.105 mm, porosity: 0.5) was used as the second permeation side flow path member 5. . As shown in FIG. 9, the separation membrane leaf was removed in the same manner as in Example 1 except that the first permeation side flow passage material was not used and the second permeation side flow passage material was extended between the separation membranes 1. Produced.
One tricot is fixed with double-sided tape to an ABS water collecting pipe (width: 1020 mm, diameter: 30 mm, number of holes 40 x 1 line), wound twice, and further connected with 25 tricots, A total of 26 tricots were used as permeate-side flow path materials for 26 bundles of membrane leaves, and were wound around the water collecting pipe as shown in FIG. Furthermore, after winding a film around the outer periphery and fixing it with tape, an edge cut, end plate attachment, and filament winding were performed to produce an 8-inch diameter element, which was then operated. The amount of water produced and the desalting rate were as shown in Table 2.

(Comparative Example 2)
A membrane leaf was produced in the same manner as in Example 1 except that the second permeation side channel material was not used. In the same manner as in Example 1, the bundle of membrane leaves was wound around a water collecting pipe as shown in FIG. 10 to produce a separation membrane element and operated. The amount of water produced and the desalting rate were as shown in Table 2.

(Comparative Example 3)
The supply-side channel material 6, the separation membrane 1, and the first permeation-side channel material 3 were produced in the same manner as in Example 1. The non-woven fabric 7 having a thickness of 0.40 mm, a porosity of 60%, and a density of 0.6 g / cm ³ was disposed so as to overlap each of the plurality of first permeation side flow path materials 3, and the second permeation side flow path A separation membrane leaf was produced in the same manner as in Example 1 except that no material was used, and the separation membrane leaf was directly wound around a water collecting pipe to produce a separation membrane element as shown in FIG. . The amount of water produced and the desalting rate were as shown in Table 2.

(Comparative Example 4)
A comparison was made except that a polyester non-woven fabric (porosity: 0.72, density: 0.40 g / cm ³ , thickness: 0.26 mm) was used as the permeation side flow path material without using the first permeation side flow path material. As in Example 1, a separation membrane element was prepared as shown in FIG. The amount of water produced and the desalting rate were as shown in Table 2.

(Comparative Example 5)
A separation membrane leaf was prepared in the same manner as in Example 1, and a tricot (thickness: 0.26 mm, groove width: 0.2 mm, ridge width: 0.3 mm, groove depth: 0. 105 mm and porosity: 0.5) were used. A tricot is wound around the water collecting pipe twice, and a plurality of bundles composed of the supply-side channel material 6, the separation membrane 1 and the first permeation-side channel material are wound to produce a separation membrane element as shown in FIG. Drove. At this time, the first permeate side channel material and the second permeate side channel material are not in contact. The amount of water produced and the desalting rate were as shown in Table 2.

As can be seen from Tables 1 and 2, the separation membrane element of the present invention can improve the amount of water produced by the separation membrane element.

DESCRIPTION OF SYMBOLS 1 Separation membrane 11 Supply side surface 12 Permeation side surface 3 First permeation side flow path material 3a Component of first permeation side flow path material 4 First permeation side flow path 5 Second permeation side flow path material 6 Supply side Channel material 7 Non-woven fabric 80 Membrane leaf 9 Water collecting pipe 100 Separation membrane element b Spacing between adjacent first permeate side channel material d Width of first permeate side channel material x Second direction (collection pipe In the longitudinal direction)
y First direction (around direction of membrane leaf)

Claims

Having a water collection tube and a membrane leaf wound around the water collection tube;
The membrane leaf includes a supply-side channel material, a separation membrane, a first permeate-side channel material, and a second permeate-side channel material;
A supply-side channel material is provided on the supply surface side of the separation membrane;
Having the first permeate-side channel material on the permeate surface side of the separation membrane;
The first permeate channel material is not continuous in the longitudinal direction of the water collection pipe;
The second permeate-side channel material is a sheet-like material and is present at one end of the membrane leaf; the second permeate-side channel material is the most of the members constituting the membrane leaf A separation membrane element that is wound around the outer peripheral surface of the water collecting pipe nearby; and the second permeate side channel member is at least in contact with the end portion of the first permeate side channel member .
The second permeate side channel material overlaps at least the end of the first permeate side channel material and the first permeate side channel material;
The separation membrane element according to claim 1.
The separation membrane element according to claim 1 or 2, wherein a porosity in a cross section in the thickness direction of the second permeation side channel material is 30 to 80%.
The separation membrane element according to any one of claims 1 to 3, wherein a thickness of the second permeation side channel material is 0.01 to 0.4 mm.
The apparent density of the second permeation side channel material is 0.3 to 1.2 g / cm 3 .
The separation membrane element according to any one of claims 1 to 4.
The thickness of the first permeate side channel material is 0.05 mm or more and 0.8 mm or less,
The separation membrane element according to any one of claims 1 to 5.
The first permeate side channel material is
Provided at intervals of 200 to 1500 μm in the longitudinal direction of the water collecting pipe,
The separation membrane element according to any one of claims 1 to 6.
The separation membrane element according to any one of claims 1 to 7, wherein a projected area ratio of the first permeate-side channel material to the separation membrane is 0.3 or more and 0.7 or less.